@article {pmid30891218, year = {2019}, author = {Bayliss, SLJ and Scott, ZR and Coffroth, MA and terHorst, CP}, title = {Genetic variation in Breviolum antillogorgium, a coral reef symbiont, in response to temperature and nutrients.}, journal = {Ecology and evolution}, volume = {9}, number = {5}, pages = {2803-2813}, doi = {10.1002/ece3.4959}, pmid = {30891218}, issn = {2045-7758}, abstract = {Symbionts within the family Symbiodiniaceae are important on coral reefs because they provide significant amounts of carbon to many different reef species. The breakdown of this mutualism that occurs as a result of increasingly warmer ocean temperatures is a major threat to coral reef ecosystems globally. Recombination during sexual reproduction and high rates of somatic mutation can lead to increased genetic variation within symbiont species, which may provide the fuel for natural selection and adaptation. However, few studies have asked whether such variation in functional traits exists within these symbionts. We used several genotypes of two closely related species, Breviolum antillogorgium and B. minutum, to examine variation of traits related to symbiosis in response to increases in temperature or nitrogen availability in laboratory cultures. We found significant genetic variation within and among symbiont species in chlorophyll content, photosynthetic efficiency, and growth rate. Two genotypes showed decreases in traits in response to increased temperatures predicted by climate change, but one genotype responded positively. Similarly, some genotypes within a species responded positively to high-nitrogen environments, such as those expected within hosts or eutrophication associated with global change, while other genotypes in the same species responded negatively, suggesting context-dependency in the strength of mutualism. Such variation in traits implies that there is potential for natural selection on symbionts in response to temperature and nutrients, which could confer an adaptive advantage to the holobiont.}, }
@article {pmid30883643, year = {2019}, author = {Tarquinio, F and Hyndes, GA and Laverock, B and Koenders, A and Säwström, C}, title = {The seagrass holobiont: understanding seagrass-bacteria interactions and their role in seagrass ecosystem functioning.}, journal = {FEMS microbiology letters}, volume = {}, number = {}, pages = {}, doi = {10.1093/femsle/fnz057}, pmid = {30883643}, issn = {1574-6968}, abstract = {This review shows that the presence of seagrass microbial community is critical for the development of seagrasses; from seed germination, through to phytohormone production and enhanced nutrient availability, and defence against pathogens and saprophytes. The tight seagrass-bacterial relationship highlighted in this review supports the existence of a seagrass holobiont and adds to the growing evidence for the importance of marine eukaryotic microorganisms in sustaining vital ecosystems. Incorporating a micro-scale view on seagrass ecosystems substantially expands our understanding of ecosystem functioning and may have significant implications for future seagrass management and mitigation against human disturbance.}, }
@article {pmid30868729, year = {2019}, author = {Thomashow, LS and Quak, YS and Weller, DM}, title = {ROOT-ASSOCIATED MICROBES IN SUSTAINABLE AGRICULTURE: MODELS, METABOLITES AND MECHANISMS.}, journal = {Pest management science}, volume = {}, number = {}, pages = {}, doi = {10.1002/ps.5406}, pmid = {30868729}, issn = {1526-4998}, abstract = {Since the discovery of penicillin in 1928 and throughout the "age of antibiotics" from the 1940s until the 1980s, the detection of novel antibiotics was restricted by lack of knowledge about the distribution and ecology of antibiotic producers in nature. The discovery that a phenazine compound produced by Pseudomonas bacteria could suppress soilborne plant pathogens, and its recovery from rhizosphere soil in 1990, provided the first incontrovertible evidence that natural metabolites could control plant pathogens in the environment and opened a new era in biological control by root-associated rhizobacteria. More recently, the advent of genomics, the availability of highly sensitive bioanalytical instrumentation, and the discovery of protective endophytes have accelerated progress toward overcoming many of the impediments that until now have limited the exploitation of beneficial plant-associated microbes to enhance agricultural sustainability. Here, we present key developments that have established the importance of these microbes in the control of pathogens, discuss concepts resulting from the exploration of classical model systems, and highlight advances emerging from ongoing investigations. This article is protected by copyright. All rights reserved.}, }
@article {pmid30863387, year = {2019}, author = {Weigel, BL and Pfister, CA}, title = {Successional Dynamics and Seascape-Level Patterns of Microbial Communities on the Canopy-Forming Kelps Nereocystis luetkeana and Macrocystis pyrifera.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {346}, doi = {10.3389/fmicb.2019.00346}, pmid = {30863387}, issn = {1664-302X}, abstract = {Canopy-forming kelps create underwater forests that are among the most productive marine ecosystems. On the Pacific coast of North America, two canopy-forming kelps with contrasting life histories co-occur; Macrocystis pyrifera, a perennial species, and Nereocystis luetkeana, an annual species. Kelp blade-associated microbes were sampled from 12 locations across a spatial gradient in Washington, United States, from the outer Pacific Coast to Puget Sound. Microbial communities were characterized using next-generation Illumina sequencing of 16S rRNA genes. At higher taxonomic levels (bacterial phylum and class), canopy-forming kelps hosted remarkably similar microbial communities, but at the amplicon sequence variant level, microbial communities on M. pyrifera and N. luetkeana were host-specific and distinct from free-living bacteria in the surrounding seawater. Microbial communities associated with blades of each kelp species displayed significant geographic variation. The microbiome of N. luetkeana changed along the spatial gradient and was significantly correlated to salinity, with outer Pacific coast sites enriched in Bacteroidetes (family Saprospiraceae) and Gammaproteobacteria (Granulosicoccus sp.), and southern Puget Sound sites enriched in Alphaproteobacteria (family Hyphomonadaceae). We also examined microbial community development and succession on meristematic and apical N. luetkeana blade tissues throughout the summer growing season on Tatoosh Island, WA. Across all dates, microbial communities were less diverse on younger, meristematic blade tissue compared to the older, apical tissues. In addition, phylogenetic relatedness among microbial taxa increased from meristematic to apical blade tissues, suggesting that the addition of microbial taxa to the community was a non-random process that selected for certain phylogenetic groups of microbes. Microbial communities on older, apical tissues displayed significant temporal variation throughout the summer and microbial taxa that were differentially abundant over time displayed clear patterns of community succession. Overall, we report that host species identity, geographic location, and blade tissue age shape the microbial communities on canopy-forming kelps.}, }
@article {pmid30830434, year = {2018}, author = {Reverter, M and Tribalat, MA and Pérez, T and Thomas, OP}, title = {Metabolome variability for two Mediterranean sponge species of the genus Haliclona: specificity, time, and space.}, journal = {Metabolomics : Official journal of the Metabolomic Society}, volume = {14}, number = {9}, pages = {114}, doi = {10.1007/s11306-018-1401-5}, pmid = {30830434}, issn = {1573-3890}, support = {PBA/MB/16/01//Marine Institute/ ; }, abstract = {INTRODUCTION: The study of natural variation of metabolites brings valuable information on the physiological state of the organisms as well as their phenotypic traits. In marine organisms, metabolome variability has mostly been addressed through targeted studies on metabolites of ecological or pharmaceutical interest. However, comparative metabolomics has demonstrated its potential to address the overall and complex metabolic variability of organisms.<br><br>OBJECTIVES: In this study, the intraspecific (temporal and spatial) variability of two Mediterranean Haliclona sponges (H. fulva and H. mucosa) was investigated through an untargeted and then targeted metabolomics approach and further compared to their interspecific variability.<br><br>METHODS: Samples of both species were collected monthly during 1 year in the coralligenous habitat of the Northwestern Mediterranean sae at Marseille and Nice. Their metabolomic profiles were obtained by UHPLC-QqToF analyses.<br><br>RESULTS: Marked variations were noticed in April and May for both species including a decrease in Shannon's diversity and concentration in specialized metabolites together with an increase in fatty acids and lyso-PAF like molecules. Spatial variations across different sampling sites could also be observed for both species, however in a lesser extent.<br><br>CONCLUSIONS: Synchronous metabolic changes possibly triggered by physiological factors like reproduction and/or environmental factors like an increase in the water temperature were highlighted for both Mediterranean Haliclona species inhabiting close habitats but displaying different biosynthetic pathways. Despite significative intraspecific variations, metabolomic variability remains minor when compared to interspecific variations for these congenerous species, therefore suggesting the predominance of genetic information of the holobiont in the observed metabolome.}, }
@article {pmid30811993, year = {2019}, author = {Kong, HG and Kim, HH and Chung, JH and Jun, J and Lee, S and Kim, HM and Jeon, S and Park, SG and Bhak, J and Ryu, CM}, title = {The Galleria mellonella Hologenome Supports Microbiota-Independent Metabolism of Long-Chain Hydrocarbon Beeswax.}, journal = {Cell reports}, volume = {26}, number = {9}, pages = {2451-2464.e5}, doi = {10.1016/j.celrep.2019.02.018}, pmid = {30811993}, issn = {2211-1247}, abstract = {The greater wax moth, Galleria mellonella, degrades wax and plastic molecules. Despite much interest, the genetic basis of these hallmark traits remains poorly understood. Herein, we assembled high-quality genome and transcriptome data from G. mellonella to investigate long-chain hydrocarbon wax metabolism strategies. Specific carboxylesterase and lipase and fatty-acid-metabolism-related enzymes in the G. mellonella genome are transcriptionally regulated during feeding on beeswax. Strikingly, G. mellonella lacking intestinal microbiota successfully decomposes long-chain fatty acids following wax metabolism, although the intestinal microbiome performs a supplementary role in short-chain fatty acid degradation. Notably, final wax derivatives were detected by gas chromatography even in the absence of gut microbiota. Our findings provide insight into wax moth adaptation and may assist in the development of unique wax-degradation strategies with a similar metabolic approach for a plastic molecule polyethylene biodegradation using organisms without intestinal microbiota.}, }
@article {pmid30811665, year = {2019}, author = {Fuentes, A}, title = {Holobionts, Multispecies Ecologies, and the Biopolitics of Care: Emerging Landscapes of Praxis in a Medical Anthropology of the Anthropocene.}, journal = {Medical anthropology quarterly}, volume = {}, number = {}, pages = {}, doi = {10.1111/maq.12492}, pmid = {30811665}, issn = {0745-5194}, abstract = {Medical anthropology, given its diversity of practical and historical entanglements with (and outside of) numerous threads of anthropology, is a key site for productive theoretical and methodological confluences in the Anthropocene. Multispecies approaches, ethnographically, theoretically and methodologically, are developing as central locations for the hybridization and mingling of diverse and innovative research questions, particularly those engaging the processes, patterns, and constructs of health.}, }
@article {pmid30809207, year = {2019}, author = {Chakravarti, LJ and Negri, AP and van Oppen, MJH}, title = {Thermal and Herbicide Tolerances of Chromerid Algae and Their Ability to Form a Symbiosis With Corals.}, journal = {Frontiers in microbiology}, volume = {10}, number = {}, pages = {173}, doi = {10.3389/fmicb.2019.00173}, pmid = {30809207}, issn = {1664-302X}, abstract = {Reef-building corals form an obligate symbiosis with photosynthetic microalgae in the family Symbiodiniaceae that meet most of their energy requirements. This symbiosis is under threat from the unprecedented rate of ocean warming as well as the simultaneous pressure of local stressors such as poor water quality. Only 1°C above mean summer sea surface temperatures (SSTs) on the Great Barrier Reef (GBR) can trigger the loss of Symbiodiniaceae from the host, and very low concentrations of the most common herbicide, diuron, can disrupt the photosynthetic activity of microalgae. In an era of rapid environmental change, investigation into the assisted evolution of the coral holobiont is underway in an effort to enhance the resilience of corals. Apicomplexan-like microalgae were discovered in 2008 and the Phylum Chromerida (chromerids) was created. Chromerids have been isolated from corals and contain a functional photosynthetic plastid. Their discovery therefore opens a new avenue of research into the use of alternative/additional photosymbionts of corals. However, only two studies to-date have investigated the symbiotic nature of Chromera velia with corals and thus little is known about the coral-chromerid relationship. Furthermore, the response of chromerids to environmental stressors has not been examined. Here we tested the performance of four chromerid strains and the common dinoflagellate symbiont Cladocopium goreaui (formerly Symbiodinium goreaui, ITS2 type C1) in response to elevated temperature, diuron and their combined exposure. Three of the four chromerid strains exhibited high thermal tolerances and two strains showed exceptional herbicide tolerances, greater than observed for any photosynthetic microalgae, including C. goreaui. We also investigated the onset of symbiosis between the chromerids and larvae of two common GBR coral species under ambient and stress conditions. Levels of colonization of coral larvae with the chromerid strains were low compared to colonization with C. goreaui. We did not observe any overall negative or positive larval fitness effects of the inoculation with chromerid algae vs. C. goreaui. However, we cannot exclude the possibility that chromerid algae may have more important roles in later coral life stages and recommend this be the focus of future studies.}, }
@article {pmid30773714, year = {2019}, author = {Estellé, J}, title = {Benefits from the joint analysis of host genomes and metagenomes: Select the holobiont.}, journal = {Journal of animal breeding and genetics = Zeitschrift fur Tierzuchtung und Zuchtungsbiologie}, volume = {136}, number = {2}, pages = {75-76}, doi = {10.1111/jbg.12383}, pmid = {30773714}, issn = {1439-0388}, }
@article {pmid30740275, year = {2019}, author = {Glasl, B and Smith, CE and Bourne, DG and Webster, NS}, title = {Disentangling the effect of host-genotype and environment on the microbiome of the coral Acropora tenuis.}, journal = {PeerJ}, volume = {7}, number = {}, pages = {e6377}, doi = {10.7717/peerj.6377}, pmid = {30740275}, issn = {2167-8359}, abstract = {Genotype-specific contributions to the environmental tolerance and disease susceptibility of corals are widely accepted. Yet our understanding of how host genotype influences the composition and stability of the coral microbiome subjected to environmental fluctuations is limited. To gain insight into the community dynamics and environmental stability of microbiomes associated with distinct coral genotypes, we assessed the microbial community associated with Acropora tenuis under single and cumulative pressure experiments. Experimental treatments comprised either a single pulse of reduced salinity (minimum of 28 psu) or exposure to the cumulative pressures of reduced salinity (minimum of 28 psu), elevated seawater temperature (+2 °C), elevated pCO2 (900 ppm), and the presence of macroalgae. Analysis of 16S rRNA gene amplicon sequence data revealed that A. tenuis microbiomes were highly host-genotype specific and maintained high compositional stability irrespective of experimental treatment. On average, 48% of the A. tenuis microbiome was dominated by Endozoicomonas. Amplicon sequence variants (ASVs) belonging to this genus were significantly different between host individuals. Although no signs of stress were evident in the coral holobiont and the vast majority of ASVs remained stable across treatments, a microbial indicator approach identified 26 ASVs belonging to Vibrionaceae, Rhodobacteraceae, Hahellaceae, Planctomycetes, Phylobacteriaceae, Flavobacteriaceae, and Cryomorphaceae that were significantly enriched in corals exposed to single and cumulative stressors. While several recent studies have highlighted the efficacy of microbial indicators as sensitive markers for environmental disturbance, the high host-genotype specificity of coral microbiomes may limit their utility and we therefore recommend meticulous control of host-genotype effects in coral microbiome research.}, }
@article {pmid30738790, year = {2019}, author = {Liu, H and Brettell, LE}, title = {Plant Defense by VOC-Induced Microbial Priming.}, journal = {Trends in plant science}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.tplants.2019.01.008}, pmid = {30738790}, issn = {1878-4372}, abstract = {The plant holobiont extends the plant's capacity for nutrient acquisition and stress protection. Recent studies show that under biotic stress plants can promote the acquisition of certain beneficial bacteria to their rhizosphere. Active emission of volatile organic compounds (VOCs) is a newly identified mechanism utilized by plants for this process.}, }
@article {pmid30727955, year = {2019}, author = {Détrée, C and Haddad, I and Demey-Thomas, E and Vinh, J and Lallier, FH and Tanguy, A and Mary, J}, title = {Global host molecular perturbations upon in situ loss of bacterial endosymbionts in the deep-sea mussel Bathymodiolus azoricus assessed using proteomics and transcriptomics.}, journal = {BMC genomics}, volume = {20}, number = {1}, pages = {109}, doi = {10.1186/s12864-019-5456-0}, pmid = {30727955}, issn = {1471-2164}, abstract = {BACKGROUND: Colonization of deep-sea hydrothermal vents by most invertebrates was made efficient through their adaptation to a symbiotic lifestyle with chemosynthetic bacteria, the primary producers in these ecosystems. Anatomical adaptations such as the establishment of specialized cells or organs have been evidenced in numerous deep-sea invertebrates. However, very few studies detailed global inter-dependencies between host and symbionts in these ecosystems. In this study, we proposed to describe, using a proteo-transcriptomic approach, the effects of symbionts loss on the deep-sea mussel Bathymodiolus azoricus' molecular biology. We induced an in situ depletion of symbionts and compared the proteo-transcriptome of the gills of mussels in three conditions: symbiotic mussels (natural population), symbiont-depleted mussels and aposymbiotic mussels.<br><br>RESULTS: Global proteomic and transcriptomic results evidenced a global disruption of host machinery in aposymbiotic organisms. We observed that the total number of proteins identified decreased from 1118 in symbiotic mussels to 790 in partially depleted mussels and 761 in aposymbiotic mussels. Using microarrays we identified 4300 transcripts differentially expressed between symbiont-depleted and symbiotic mussels. Among these transcripts, 799 were found differentially expressed in aposymbiotic mussels and almost twice as many in symbiont-depleted mussels as compared to symbiotic mussels. Regarding apoptotic and immune system processes - known to be largely involved in symbiotic interactions - an overall up-regulation of associated proteins and transcripts was observed in symbiont-depleted mussels.<br><br>CONCLUSION: Overall, our study showed a global impairment of host machinery and an activation of both the immune and apoptotic system following symbiont-depletion. One of the main assumptions is the involvement of symbiotic bacteria in the inhibition and regulation of immune and apoptotic systems. As such, symbiotic bacteria may increase their lifespan in gill cells while managing the defense of the holobiont against putative pathogens.}, }
@article {pmid30720424, year = {2019}, author = {Rosenberg, E and Zilber-Rosenberg, I}, title = {The Hologenome Concept of Evolution: Medical Implications.}, journal = {Rambam Maimonides medical journal}, volume = {10}, number = {1}, pages = {}, doi = {10.5041/RMMJ.10359}, pmid = {30720424}, issn = {2076-9172}, abstract = {All natural animals and plants are holobionts, consisting of the host and microbiome, which is composed of abundant and diverse microorganisms. Health and disease of holobionts depend as much on interactions between host and microbiome and within the microbiome, as on interactions between organs and body parts of the host. Recent evidence indicates that a significant fraction of the microbiome is transferred by a variety of mechanisms from parent to offspring for many generations. Genetic variation in holobionts can occur in the microbiome as well as in the host genome, and it occurs more rapidly and by more mechanisms in genomes of microbiomes than in host genomes (e.g. via acquisition of novel microbes and horizontal gene transfer of microbial genes into host chromosomes). Evidence discussed in this review supports the concept that holobionts with their hologenomes can be considered levels of selection in evolution. Though changes in the microbiome can lead to evolution of the holobiont, it can also lead to dysbiosis and diseases (e.g. obesity, diarrhea, inflammatory bowel disease, and autism). In practice, the possibility of manipulating microbiomes offers the potential to prevent and cure diseases.}, }
@article {pmid30718608, year = {2019}, author = {Longford, SR and Campbell, AH and Nielsen, S and Case, RJ and Kjelleberg, S and Steinberg, PD}, title = {Interactions within the microbiome alter microbial interactions with host chemical defences and affect disease in a marine holobiont.}, journal = {Scientific reports}, volume = {9}, number = {1}, pages = {1363}, doi = {10.1038/s41598-018-37062-z}, pmid = {30718608}, issn = {2045-2322}, abstract = {Our understanding of diseases has been transformed by the realisation that people are holobionts, comprised of a host and its associated microbiome(s). Disease can also have devastating effects on populations of marine organisms, including dominant habitat formers such as seaweed holobionts. However, we know very little about how interactions between microorganisms within microbiomes - of humans or marine organisms - affect host health and there is no underpinning theoretical framework for exploring this. We applied ecological models of succession to bacterial communities to understand how interactions within a seaweed microbiome affect the host. We observed succession of surface microbiomes on the red seaweed Delisea pulchra in situ, following a disturbance, with communities 'recovering' to resemble undisturbed states after only 12 days. Further, if this recovery was perturbed, a bleaching disease previously described for this seaweed developed. Early successional strains of bacteria protected the host from colonisation by a pathogenic, later successional strain. Host chemical defences also prevented disease, such that within-microbiome interactions were most important when the host's chemical defences were inhibited. This is the first experimental evidence that interactions within microbiomes have important implications for host health and disease in a dominant marine habitat-forming organism.}, }
@article {pmid30691243, year = {2019}, author = {Wemheuer, B and Thomas, T and Wemheuer, F}, title = {Fungal Endophyte Communities of Three Agricultural Important Grass Species Differ in Their Response Towards Management Regimes.}, journal = {Microorganisms}, volume = {7}, number = {2}, pages = {}, doi = {10.3390/microorganisms7020037}, pmid = {30691243}, issn = {2076-2607}, support = {Functional Biodiversity Research//Niedersächsisches Ministerium für Wissenschaft und Kultur/ ; Starting Grant//Georg-August-Universität Göttingen/ ; }, abstract = {Despite the importance of endophytic fungi for plant health, it remains unclear how these fungi are influenced by grassland management practices. Here, we investigated the effect of fertilizer application and mowing frequency on fungal endophyte communities and their life strategies in aerial tissues of three agriculturally important grass species (Dactylisglomerata L., Festucarubra L. and Loliumperenne L.) over two consecutive years. Our results showed that the management practices influenced fungal communities in the plant holobiont, but observed effects differed between grass species and sampling year. Phylogenetic diversity of fungal endophytes in D. glomerata was significantly affected by mowing frequency in 2010, whereas fertilizer application and the interaction of fertilization with mowing frequency had a significant impact on community composition of L. perenne in 2010 and 2011, respectively. Taken together, our research provides a basis for future studies on responses of fungal endophytes towards management practices. To the best of our knowledge, this is the first study simultaneously assessing fungal endophyte communities in aerial parts of three agriculturally important grass species over two consecutive years.}, }
@article {pmid30680121, year = {2019}, author = {Helmkampf, M and Bellinger, MR and Frazier, M and Takabayashi, M}, title = {Symbiont type and environmental factors affect transcriptome-wide gene expression in the coral Montipora capitata.}, journal = {Ecology and evolution}, volume = {9}, number = {1}, pages = {378-392}, doi = {10.1002/ece3.4756}, pmid = {30680121}, issn = {2045-7758}, abstract = {Reef-building corals may harbor genetically distinct lineages of endosymbiotic dinoflagellates in the genus Symbiodinium, which have been shown to affect important colony properties, including growth rates and resilience against environmental stress. However, the molecular processes underlying these differences are not well understood. In this study, we used whole transcriptome sequencing (RNA-seq) to assess gene expression differences between 27 samples of the coral Montipora capitata predominantly hosting two different Symbiodinium types in clades C and D. The samples were further characterized by their origin from two field sites on Hawai'i Island with contrasting environmental conditions. We found that transcriptome-wide gene expression profiles clearly separated by field site first, and symbiont clade second. With 273 differentially expressed genes (DEGs, 1.3% of all host transcripts), symbiont clade had a measurable effect on host gene expression, but the effect of field site proved almost an order of magnitude higher (1,957 DEGs, 9.6%). According to SNP analysis, we found moderate evidence for host genetic differentiation between field sites (FST = 0.046) and among corals harboring alternative symbiont clades (FST = 0.036), suggesting that site-related gene expression differences are likely due to a combination of local adaptation and acclimatization to environmental factors. The correlation between host gene expression and symbiont clade may be due to several factors, including host genotype or microhabitat selecting for alternative clades, host physiology responding to different symbionts, or direct modulation of host gene expression by Symbiodinium. However, the magnitude of these effects at the level of transcription was unexpectedly small considering the contribution of symbiont type to holobiont phenotype.}, }
@article {pmid30662570, year = {2019}, author = {Töpel, M and Pinder, MIM and Johansson, ON and Kourtchenko, O and Clarke, AK and Godhe, A}, title = {Complete Genome Sequence of Novel Sulfitobacter pseudonitzschiae Strain SMR1, Isolated from a Culture of the Marine Diatom Skeletonema marinoi.}, journal = {Journal of genomics}, volume = {7}, number = {}, pages = {7-10}, doi = {10.7150/jgen.30559}, pmid = {30662570}, issn = {1839-9940}, abstract = {When studying diatoms, an important consideration is the role of associated bacteria in the diatom-microbiome holobiont. To that end, bacteria isolated from a culture of Skeletonema marinoi strain R05AC were sequenced, one of which being bacterial strain SMR1, presented here. The genome consists of a circular chromosome and seven circular plasmids, totalling 5,121,602 bp. After phylotaxonomic analysis and 16S rRNA sequence comparison, we place this strain in the taxon Sulfitobacter pseudonitzschiae on account of similarity to the type strain. The annotated genome suggests similar interactions between strain SMR1 and its host diatom as have been shown previously in diatom-associated Sulfitobacter, for example bacterial production of growth hormone for its host, and breakdown of diatom-derived DMSP by Sulfitobacter for use as a sulfur source.}, }
@article {pmid30635058, year = {2019}, author = {Simon, JC and Marchesi, JR and Mougel, C and Selosse, MA}, title = {Host-microbiota interactions: from holobiont theory to analysis.}, journal = {Microbiome}, volume = {7}, number = {1}, pages = {5}, doi = {10.1186/s40168-019-0619-4}, pmid = {30635058}, issn = {2049-2618}, abstract = {In the recent years, the holobiont concept has emerged as a theoretical and experimental framework to study the interactions between hosts and their associated microbial communities in all types of ecosystems. The spread of this concept in many branches of biology results from the fairly recent realization of the ubiquitous nature of host-associated microbes and their central role in host biology, ecology, and evolution. Through this special series &quot;Host-microbiota interactions: from holobiont theory to analysis,&quot; we wanted to promote this field of research which has considerable implications for human health, food production, and ecosystem protection. In this preface, we highlight a collection of articles selected for this special issue that show, use, or debate the concept of holobiont to approach taxonomically and ecologically diverse organisms, from humans and plants to sponges and insects. We also identify some theoretical and methodological challenges and propose directions for future research on holobionts.}, }
@article {pmid30621755, year = {2018}, author = {Osmanovic, D and Kessler, DA and Rabin, Y and Soen, Y}, title = {Darwinian selection of host and bacteria supports emergence of Lamarckian-like adaptation of the system as a whole.}, journal = {Biology direct}, volume = {13}, number = {1}, pages = {24}, doi = {10.1186/s13062-018-0224-7}, pmid = {30621755}, issn = {1745-6150}, support = {1902/12//Israel Science Foundation/ ; 2015619//United States - Israel Binational Science Foundation/ ; 40663//John Templeton Foundation/ ; }, abstract = {BACKGROUND: The relatively fast selection of symbiotic bacteria within hosts and the potential transmission of these bacteria across generations of hosts raise the question of whether interactions between host and bacteria support emergent adaptive capabilities beyond those of germ-free hosts.<br><br>RESULTS: To investigate possibilities for emergent adaptations that may distinguish composite host-microbiome systems from germ-free hosts, we introduce a population genetics model of a host-microbiome system with vertical transmission of bacteria. The host and its bacteria are jointly exposed to a toxic agent, creating a toxic stress that can be alleviated by selection of resistant individuals and by secretion of a detoxification agent (&quot;detox&quot;). We show that toxic exposure in one generation of hosts leads to selection of resistant bacteria, which in turn, increases the toxic tolerance of the host's offspring. Prolonged exposure to toxin over many host generations promotes anadditional form of emergent adaptation due to selection of hosts based on detox produced by their bacterial community as a whole (as opposed to properties of individual bacteria).<br><br>CONCLUSIONS: These findings show that interactions between pure Darwinian selections of host and its bacteria can give rise to emergent adaptive capabilities, including Lamarckian-like adaptation of the host-microbiome system.<br><br>REVIEWERS: This article was reviewed by Eugene Koonin, Yuri Wolf and Philippe Huneman.}, }
@article {pmid30618841, year = {2018}, author = {Huitzil, S and Sandoval-Motta, S and Frank, A and Aldana, M}, title = {Modeling the Role of the Microbiome in Evolution.}, journal = {Frontiers in physiology}, volume = {9}, number = {}, pages = {1836}, doi = {10.3389/fphys.2018.01836}, pmid = {30618841}, issn = {1664-042X}, abstract = {There is undeniable evidence showing that bacteria have strongly influenced the evolution and biological functions of multicellular organisms. It has been hypothesized that many host-microbial interactions have emerged so as to increase the adaptive fitness of the holobiont (the host plus its microbiota). Although this association has been corroborated for many specific cases, general mechanisms explaining the role of the microbiota in the evolution of the host are yet to be understood. Here we present an evolutionary model in which a network representing the host adapts in order to perform a predefined function. During its adaptation, the host network (HN) can interact with other networks representing its microbiota. We show that this interaction greatly accelerates and improves the adaptability of the HN without decreasing the adaptation of the microbial networks. Furthermore, the adaptation of the HN to perform several functions is possible only when it interacts with many different bacterial networks in a specialized way (each bacterial network participating in the adaptation of one function). Disrupting these interactions often leads to non-adaptive states, reminiscent of dysbiosis, where none of the networks the holobiont consists of can perform their respective functions. By considering the holobiont as a unit of selection and focusing on the adaptation of the host to predefined but arbitrary functions, our model predicts the need for specialized diversity in the microbiota. This structural and dynamical complexity in the holobiont facilitates its adaptation, whereas a homogeneous (non-specialized) microbiota is inconsequential or even detrimental to the holobiont's evolution. To our knowledge, this is the first model in which symbiotic interactions, diversity, specialization and dysbiosis in an ecosystem emerge as a result of coevolution. It also helps us understand the emergence of complex organisms, as they adapt more easily to perform multiple tasks than non-complex ones.}, }
@article {pmid30613848, year = {2019}, author = {Ye, S and Bhattacharjee, M and Siemann, E}, title = {Thermal Tolerance in Green Hydra: Identifying the Roles of Algal Endosymbionts and Hosts in a Freshwater Holobiont Under Stress.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-01315-1}, pmid = {30613848}, issn = {1432-184X}, abstract = {It has been proposed that holobionts (host-symbiont units) could swap endosymbionts, rapidly alter the hologenome (host plus symbiont genome), and increase their stress tolerance. However, experimental tests of individual and combined contributions of hosts and endosymbionts to holobiont stress tolerance are needed to test this hypothesis. Here, we used six green hydra (Hydra viridissima) strains to tease apart host (hydra) and symbiont (algae) contributions to thermal tolerance. Heat shock experiments with (1) hydra with their original symbionts, (2) aposymbiotic hydra (algae removed), (3) novel associations (a single hydra strain hosting different algae individually), and (4) control hydra (aposymbiotic hydra re-associated with their original algae) showed high variation in thermal tolerance in each group. Relative tolerances of strains were the same within original, aposymbiotic, and control treatments, but reversed in the novel associations group. Aposymbiotic hydra had similar or higher thermal tolerance than hydra with algal symbionts. Selection on the holobiont appears to be stronger than on either partner alone, suggesting endosymbiosis could become an evolutionary trap under climate change. Our results suggest that green hydra thermal tolerance is strongly determined by the host, with a smaller, non-positive role for the algal symbiont. Once temperatures exceed host tolerance limits, swapping symbionts is unlikely to allow these holobionts to persist. Rather, increases in host tolerance through in situ adaptation or migration of pre-adapted host strains appear more likely to increase local thermal tolerance. Overall, our results indicate green hydra is a valuable system for studying aquatic endosymbiosis under changing environmental conditions, and demonstrate how the host and the endosymbiont contribute to holobiont stress tolerance.}, }
@article {pmid30611207, year = {2019}, author = {Kamm, K and Schierwater, B and DeSalle, R}, title = {Innate immunity in the simplest animals - placozoans.}, journal = {BMC genomics}, volume = {20}, number = {1}, pages = {5}, doi = {10.1186/s12864-018-5377-3}, pmid = {30611207}, issn = {1471-2164}, support = {Schi-277/26//Deutsche Forschungsgemeinschaft/ ; Schi-277/27//Deutsche Forschungsgemeinschaft/ ; Schi-277/29//Deutsche Forschungsgemeinschaft/ ; }, abstract = {BACKGROUND: Innate immunity provides the core recognition system in animals for preventing infection, but also plays an important role in managing the relationship between an animal host and its symbiont. Most of our knowledge about innate immunity stems from a few animal model systems, but substantial variation between metazoan phyla has been revealed by comparative genomic studies. The exploration of more taxa is still needed to better understand the evolution of immunity related mechanisms. Placozoans are morphologically the simplest organized metazoans and the association between these enigmatic animals and their rickettsial endosymbionts has recently been elucidated. Our analyses of the novel placozoan nuclear genome of Trichoplax sp. H2 and its associated rickettsial endosymbiont genome clearly pointed to a mutualistic and co-evolutionary relationship. This discovery raises the question of how the placozoan holobiont manages symbiosis and, conversely, how it defends against harmful microorganisms. In this study, we examined the annotated genome of Trichoplax sp. H2 for the presence of genes involved in innate immune recognition and downstream signaling.<br><br>RESULTS: A rich repertoire of genes belonging to the Toll-like and NOD-like receptor pathways, to scavenger receptors and to secreted fibrinogen-related domain genes was identified in the genome of Trichoplax sp. H2. Nevertheless, the innate immunity related pathways in placozoans deviate in several instances from well investigated vertebrates and invertebrates. While true Toll- and NOD-like receptors are absent, the presence of many genes of the downstream signaling cascade suggests at least primordial Toll-like receptor signaling in Placozoa. An abundance of scavenger receptors, fibrinogen-related domain genes and Apaf-1 genes clearly constitutes an expansion of the immunity related gene repertoire specific to Placozoa.<br><br>CONCLUSIONS: The found wealth of immunity related genes present in Placozoa is surprising and quite striking in light of the extremely simple placozoan body plan and their sparse cell type makeup. Research is warranted to reveal how Placozoa utilize this immune repertoire to manage and maintain their associated microbiota as well as to fend-off pathogens.}, }
@article {pmid30598811, year = {2018}, author = {Rodriguez-Casariego, JA and Ladd, MC and Shantz, AA and Lopes, C and Cheema, MS and Kim, B and Roberts, SB and Fourqurean, JW and Ausio, J and Burkepile, DE and Eirin-Lopez, JM}, title = {Coral epigenetic responses to nutrient stress: Histone H2A.X phosphorylation dynamics and DNA methylation in the staghorn coral Acropora cervicornis.}, journal = {Ecology and evolution}, volume = {8}, number = {23}, pages = {12193-12207}, doi = {10.1002/ece3.4678}, pmid = {30598811}, issn = {2045-7758}, abstract = {Nutrient pollution and thermal stress constitute two of the main drivers of global change in the coastal oceans. While different studies have addressed the physiological effects and ecological consequences of these stressors in corals, the role of acquired modifications in the coral epigenome during acclimatory and adaptive responses remains unknown. The present work aims to address that gap by monitoring two types of epigenetic mechanisms, namely histone modifications and DNA methylation, during a 7-week-long experiment in which staghorn coral fragments (Acropora cervicornis) were exposed to nutrient stress (nitrogen, nitrogen + phosphorus) in the presence of thermal stress. The major conclusion of this experiment can be summarized by two main results: First, coral holobiont responses to the combined effects of nutrient enrichment and thermal stress involve the post-translational phosphorylation of the histone variant H2A.X (involved in responses to DNA damage), as well as nonsignificant modifications in DNA methylation trends. Second, the reduction in H2A.X phosphorylation (and the subsequent potential impairment of DNA repair mechanisms) observed after prolonged coral exposure to nitrogen enrichment and thermal stress is consistent with the symbiont-driven phosphorus limitation previously observed in corals subject to nitrogen enrichment. The alteration of this epigenetic mechanism could help to explain the synergistic effects of nutrient imbalance and thermal stress on coral fitness (i.e., increased bleaching and mortality) while supporting the positive effect of phosphorus addition to improving coral resilience to thermal stress. Overall, this work provides new insights into the role of epigenetic mechanisms during coral responses to global change, discussing future research directions and the potential benefits for improving restoration, management and conservation of coral reef ecosystems worldwide.}, }
@article {pmid30566939, year = {2018}, author = {Esser, D and Lange, J and Marinos, G and Sieber, M and Best, L and Prasse, D and Bathia, J and Rühlemann, MC and Boersch, K and Jaspers, C and Sommer, F}, title = {Functions of the Microbiota for the Physiology of Animal Metaorganisms.}, journal = {Journal of innate immunity}, volume = {}, number = {}, pages = {1-12}, doi = {10.1159/000495115}, pmid = {30566939}, issn = {1662-8128}, abstract = {Animals are usually regarded as independent entities within their respective environments. However, within an organism, eukaryotes and prokaryotes interact dynamically to form the so-called metaorganism or holobiont, where each partner fulfils its versatile and crucial role. This review focuses on the interplay between microorganisms and multicellular eukaryotes in the context of host physiology, in particular aging and mucus-associated crosstalk. In addition to the interactions between bacteria and the host, we highlight the importance of viruses and nonmodel organisms. Moreover, we discuss current culturing and computational methodologies that allow a deeper understanding of underlying mechanisms controlling the physiology of metaorganisms.}, }
@article {pmid30564562, year = {2018}, author = {Proal, A and Marshall, T}, title = {Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in the Era of the Human Microbiome: Persistent Pathogens Drive Chronic Symptoms by Interfering With Host Metabolism, Gene Expression, and Immunity.}, journal = {Frontiers in pediatrics}, volume = {6}, number = {}, pages = {373}, doi = {10.3389/fped.2018.00373}, pmid = {30564562}, issn = {2296-2360}, abstract = {The illness ME/CFS has been repeatedly tied to infectious agents such as Epstein Barr Virus. Expanding research on the human microbiome now allows ME/CFS-associated pathogens to be studied as interacting members of human microbiome communities. Humans harbor these vast ecosystems of bacteria, viruses and fungi in nearly all tissue and blood. Most well-studied inflammatory conditions are tied to dysbiosis or imbalance of the human microbiome. While gut microbiome dysbiosis has been identified in ME/CFS, microbes and viruses outside the gut can also contribute to the illness. Pathobionts, and their associated proteins/metabolites, often control human metabolism and gene expression in a manner that pushes the body toward a state of illness. Intracellular pathogens, including many associated with ME/CFS, drive microbiome dysbiosis by directly interfering with human transcription, translation, and DNA repair processes. Molecular mimicry between host and pathogen proteins/metabolites further complicates this interference. Other human pathogens disable mitochondria or dysregulate host nervous system signaling. Antibodies and/or clonal T cells identified in patients with ME/CFS are likely activated in response to these persistent microbiome pathogens. Different human pathogens have evolved similar survival mechanisms to disable the host immune response and host metabolic pathways. The metabolic dysfunction driven by these organisms can result in similar clusters of inflammatory symptoms. ME/CFS may be driven by this pathogen-induced dysfunction, with the nature of dysbiosis and symptom presentation varying based on a patient's unique infectious and environmental history. Under such conditions, patients would benefit from treatments that support the human immune system in an effort to reverse the infectious disease process.}, }
@article {pmid30555453, year = {2018}, author = {Cernava, T and Vasfiu, Q and Erlacher, A and Aschenbrenner, IA and Francesconi, K and Grube, M and Berg, G}, title = {Adaptions of Lichen Microbiota Functioning Under Persistent Exposure to Arsenic Contamination.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2959}, doi = {10.3389/fmicb.2018.02959}, pmid = {30555453}, issn = {1664-302X}, abstract = {Host-associated microbiota play an important role in the health and persistence of more complex organisms. In this study, metagenomic analyses were used to reveal microbial community adaptations in three lichen samples as a response to different arsenic concentrations at the sampling sites. Elevated arsenic concentrations at a former mining site expanded the spectrum and number of relevant functions in the lichen-associated microorganisms. Apparent changes affected the abundance of numerous detoxification-related genes, they were substantially enhanced in arsenic-polluted samples. Complementary quantifications of the arsenite S-adenosylmethionine methyltransferase (arsM) gene showed that its abundance is not strictly responding to the environmental arsenic concentrations. The analyzed samples contained rather low numbers of the arsM gene with a maximum of 202 gene copies μl-1 in total community DNA extracts. In addition, bacterial isolates were screened for the presence of arsM. Positive isolates were exposed to different As(III) and As(V) concentrations and tolerated up to 30 mM inorganic arsenic in fluid media, while no substantial biotransformations were observed. Obtained data deepens our understanding related to adaptions of whole microbial communities to adverse environmental conditions. Moreover, this study provides the first evidence that the integrity of bacteria in the lichen holobiont is maintained by acquisition of specific resistances.}, }
@article {pmid30542077, year = {2018}, author = {Gibbin, E and Gavish, A and Krueger, T and Kramarsky-Winter, E and Shapiro, O and Guiet, R and Jensen, L and Vardi, A and Meibom, A}, title = {Vibrio coralliilyticus infection triggers a behavioural response and perturbs nutritional exchange and tissue integrity in a symbiotic coral.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-018-0327-2}, pmid = {30542077}, issn = {1751-7370}, abstract = {Under homoeostatic conditions, the relationship between the coral Pocillopora damicornis and Vibrio coralliilyticus is commensal. An increase in temperature, or in the abundance of V. coralliilyticus, can turn this association pathogenic, causing tissue lysis, expulsion of the corals' symbiotic algae (genus Symbiodinium), and eventually coral death. Using a combination of microfluidics, fluorescence microscopy, stable isotopes, electron microscopy and NanoSIMS isotopic imaging, we provide insights into the onset and progression of V. coralliilyticus infection in the daytime and at night, at the tissue and (sub-)cellular level. The objective of our study was to connect the macro-scale behavioural response of the coral to the micro-scale nutritional interactions that occur between the host and its symbiont. In the daytime, polyps enhanced their mucus production, and actively spewed pathogens. Vibrio infection primarily resulted in the formation of tissue lesions in the coenosarc. NanoSIMS analysis revealed infection reduced 13C-assimilation in Symbiodinium, but increased 13C-assimilation in the host. In the night incubations, no mucus spewing was observed, and a mucus film was formed on the coral surface. Vibrio inoculation and infection at night showed reduced 13C-turnover in Symbiodinium, but did not impact host 13C-turnover. Our results show that both the nutritional interactions that occur between the two symbiotic partners and the behavioural response of the host organism play key roles in determining the progression and severity of host-pathogen interactions. More generally, our approach provides a new means of studying interactions (ranging from behavioural to metabolic scales) between partners involved in complex holobiont systems, under both homoeostatic and pathogenic conditions.}, }
@article {pmid30524390, year = {2018}, author = {Gobet, A and Barbeyron, T and Matard-Mann, M and Magdelenat, G and Vallenet, D and Duchaud, E and Michel, G}, title = {Evolutionary Evidence of Algal Polysaccharide Degradation Acquisition by Pseudoalteromonas carrageenovora 9T to Adapt to Macroalgal Niches.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2740}, doi = {10.3389/fmicb.2018.02740}, pmid = {30524390}, issn = {1664-302X}, abstract = {About half of seaweed biomass is composed of polysaccharides. Most of these complex polymers have a marked polyanionic character. For instance, the red algal cell wall is mainly composed of sulfated galactans, agars and carrageenans, while brown algae contain alginate and fucose-containing sulfated polysaccharides (FCSP) as cell wall polysaccharides. Some marine heterotrophic bacteria have developed abilities to grow on such macroalgal polysaccharides. This is the case of Pseudoalteromonas carrageenovora 9T (ATCC 43555T), a marine gammaproteobacterium isolated in 1955 and which was an early model organism for studying carrageenan catabolism. We present here the genomic analysis of P. carrageenovora. Its genome is composed of two chromosomes and of a large plasmid encompassing 109 protein-coding genes. P. carrageenovora possesses a diverse repertoire of carbohydrate-active enzymes (CAZymes), notably specific for the degradation of macroalgal polysaccharides (laminarin, alginate, FCSP, carrageenans). We confirm these predicted capacities by screening the growth of P. carrageenovora with a large collection of carbohydrates. Most of these CAZyme genes constitute clusters located either in the large chromosome or in the small one. Unexpectedly, all the carrageenan catabolism-related genes are found in the plasmid, suggesting that P. carrageenovora acquired its hallmark capacity for carrageenan degradation by horizontal gene transfer (HGT). Whereas P. carrageenovora is able to use lambda-carrageenan as a sole carbon source, genomic and physiological analyses demonstrate that its catabolic pathway for kappa- and iota-carrageenan is incomplete. This is due to the absence of the recently discovered 3,6-anhydro-D-galactosidase genes (GH127 and GH129 families). A genomic comparison with 52 Pseudoalteromonas strains confirms that carrageenan catabolism has been recently acquired only in a few species. Even though the loci for cellulose biosynthesis and alginate utilization are located on the chromosomes, they were also horizontally acquired. However, these HGTs occurred earlier in the evolution of the Pseudoalteromonas genus, the cellulose- and alginate-related loci being essentially present in one large, late-diverging clade (LDC). Altogether, the capacities to degrade cell wall polysaccharides from macroalgae are not ancestral in the Pseudoalteromonas genus. Such catabolism in P. carrageenovora resulted from a succession of HGTs, likely allowing an adaptation to the life on the macroalgal surface.}, }
@article {pmid30533318, year = {2018}, author = {Kenkel, CD and Bay, LK}, title = {Exploring mechanisms that affect coral cooperation: symbiont transmission mode, cell density and community composition.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e6047}, doi = {10.7717/peerj.6047}, pmid = {30533318}, issn = {2167-8359}, abstract = {The coral symbiosis is the linchpin of the reef ecosystem, yet the mechanisms that promote and maintain cooperation between hosts and symbionts have not been fully resolved. We used a phylogenetically controlled design to investigate the role of vertical symbiont transmission, an evolutionary mechanism in which symbionts are inherited directly from parents, predicted to enhance cooperation and holobiont fitness. Six species of coral, three vertical transmitters and their closest horizontally transmitting relatives, which exhibit environmental acquisition of symbionts, were fragmented and subjected to a 2-week thermal stress experiment. Symbiont cell density, photosynthetic function and translocation of photosynthetically fixed carbon between symbionts and hosts were quantified to assess changes in physiological performance and cooperation. All species exhibited similar decreases in symbiont cell density and net photosynthesis in response to elevated temperature, consistent with the onset of bleaching. Yet baseline cooperation, or translocation of photosynthate, in ambient conditions and the reduction in cooperation in response to elevated temperature differed among species. Although Porites lobata and Galaxea acrhelia did exhibit the highest levels of baseline cooperation, we did not observe universally higher levels of cooperation in vertically transmitting species. Post hoc sequencing of the Symbiodinium ITS-2 locus was used to investigate the potential role of differences in symbiont community composition. Interestingly, reductions in cooperation at the onset of bleaching tended to be associated with increased symbiont community diversity among coral species. The theoretical benefits of evolving vertical transmission are based on the underlying assumption that the host-symbiont relationship becomes genetically uniform, thereby reducing competition among symbionts. Taken together, our results suggest that it may not be vertical transmission per se that influences host-symbiont cooperation, but genetic uniformity of the symbiont community, although additional work is needed to test this hypothesis.}, }
@article {pmid30514367, year = {2018}, author = {Marasco, R and Mosqueira, MJ and Fusi, M and Ramond, JB and Merlino, G and Booth, JM and Maggs-Kölling, G and Cowan, DA and Daffonchio, D}, title = {Rhizosheath microbial community assembly of sympatric desert speargrasses is independent of the plant host.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {215}, doi = {10.1186/s40168-018-0597-y}, pmid = {30514367}, issn = {2049-2618}, support = {95565//South African National Research Foundation/ ; }, abstract = {BACKGROUND: The rhizosheath-root system is an adaptive trait of sandy-desert speargrasses in response to unfavourable moisture and nutritional conditions. Under the deserts' polyextreme conditions, plants interact with edaphic microorganisms that positively affect their fitness and resistance. However, the trophic simplicity and environmental harshness of desert ecosystems have previously been shown to strongly influence soil microbial community assembly. We hypothesize that sand-driven ecological filtering constrains the microbial recruitment processes in the speargrass rhizosheath-root niche, prevailing over the plant-induced selection.<br><br>METHODS: Bacterial and fungal communities from the rhizosheath-root compartments (endosphere root tissues, rhizosheath and rhizosphere) of three Namib Desert speargrass species (Stipagrostis sabulicola, S. seelyae and Cladoraphis spinosa) along with bulk sand have been studied to test our hypothesis. To minimize the variability determined by edaphic and climatic factors, plants living in a single dune were studied. We assessed the role of plant species vs the sandy substrate on the recruitment and selection, phylogenetic diversity and co-occurrence microbial networks of the rhizosheath-root system microbial communities.<br><br>RESULTS: Microorganisms associated with the speargrass rhizosheath-root system were recruited from the surrounding bulk sand population and were significantly enriched in the rhizosheath compartments (105 and 104 of bacterial 16S rRNA and fungal ITS copies per gram of sand to up to 108 and 107 copies per gram, respectively). Furthermore, each rhizosheath-root system compartment hosted a specific microbial community demonstrating strong niche-partitioning. The rhizosheath-root systems of the three speargrass species studied were dominated by desert-adapted Actinobacteria and Alphaproteobacteria (e.g. Lechevalieria, Streptomyces and Microvirga) as well as saprophytic Ascomycota fungi (e.g. Curvularia, Aspergillus and Thielavia). Our results clearly showed a random phylogenetic turnover of rhizosheath-root system associated microbial communities, independent of the plant species, where stochastic factors drive neutral assembly. Co-occurrence network analyses also indicated that the bacterial and fungal community members of the rhizosheath-root systems established a higher number of interactions than those in the barren bulk sand, suggesting that the former are more stable and functional than the latter.<br><br>CONCLUSION: Our study demonstrates that the rhizosheath-root system microbial communities of desert dune speargrasses are stochastically assembled and host-independent. This finding supports the concept that the selection determined by the desert sand prevails over that imposed by the genotype of the different plant species.}, }
@article {pmid30509793, year = {2018}, author = {Baquiran, JIP and Conaco, C}, title = {Sponge-microbe partnerships are stable under eutrophication pressure from mariculture.}, journal = {Marine pollution bulletin}, volume = {136}, number = {}, pages = {125-134}, doi = {10.1016/j.marpolbul.2018.09.011}, pmid = {30509793}, issn = {1879-3363}, abstract = {Sponges harbor a great diversity of symbiotic microorganisms. However, environmental stresses can affect this partnership and influence the health and abundance of the host sponges. In Bolinao, Pangasinan, Philippines, chronic input of organic materials from mariculture activities contributes to a eutrophic coastal environment. To understand how these conditions might affect sponge-microbial partnerships, transplantation experiments were conducted with the marine sponge Gelliodes obtusa. High-throughput sequencing of 16S rRNA revealed that the associated microbial community of the sponges did not exhibit significant shifts after six weeks of transplantation at a eutrophic fish farm site compared to sponges grown at a coral reef or a seagrass area. However, sponges at the fish farm revealed higher abundance of the amoA gene, suggesting that microbiome members are responsive to increased ammonium levels at the site. The stable association between G. obtusa and its microbiome indicates that the sponge holobiont can withstand eutrophication pressure from mariculture.}, }
@article {pmid30487315, year = {2018}, author = {Matthews, JL and Oakley, CA and Lutz, A and Hillyer, KE and Roessner, U and Grossman, AR and Weis, VM and Davy, SK}, title = {Partner switching and metabolic flux in a model cnidarian-dinoflagellate symbiosis.}, journal = {Proceedings. Biological sciences}, volume = {285}, number = {1892}, pages = {}, doi = {10.1098/rspb.2018.2336}, pmid = {30487315}, issn = {1471-2954}, abstract = {Metabolite exchange is fundamental to the viability of the cnidarian-Symbiodiniaceae symbiosis and survival of coral reefs. Coral holobiont tolerance to environmental change might be achieved through changes in Symbiodiniaceae species composition, but differences in the metabolites supplied by different Symbiodiniaceae species could influence holobiont fitness. Using 13C stable-isotope labelling coupled to gas chromatography-mass spectrometry, we characterized newly fixed carbon fate in the model cnidarian Exaiptasia pallida (Aiptasia) when experimentally colonized with either native Breviolum minutum or non-native Durusdinium trenchii Relative to anemones containing B. minutum, D. trenchii-colonized hosts exhibited a 4.5-fold reduction in 13C-labelled glucose and reduced abundance and diversity of 13C-labelled carbohydrates and lipogenesis precursors, indicating symbiont species-specific modifications to carbohydrate availability and lipid storage. Mapping carbon fate also revealed significant alterations to host molecular signalling pathways. In particular, D. trenchii-colonized hosts exhibited a 40-fold reduction in 13C-labelled scyllo-inositol, a potential interpartner signalling molecule in symbiosis specificity. 13C-labelling also highlighted differential antioxidant- and ammonium-producing pathway activities, suggesting physiological responses to different symbiont species. Such differences in symbiont metabolite contribution and host utilization may limit the proliferation of stress-driven symbioses; this contributes valuable information towards future scenarios that select in favour of less-competent symbionts in response to environmental change.}, }
@article {pmid30472481, year = {2018}, author = {Marangoni, LFB and Pinto, MMAN and Marques, JA and Bianchini, A}, title = {Copper exposure and seawater acidification interaction: Antagonistic effects on biomarkers in the zooxanthellate scleractinian coral Mussismilia harttii.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {206}, number = {}, pages = {123-133}, doi = {10.1016/j.aquatox.2018.11.005}, pmid = {30472481}, issn = {1879-1514}, abstract = {Coral reefs are threatened by global and local impacts, such as ocean acidification (OA) and metal contamination. Toxicity of metals, such as copper (Cu), is expected to be enhanced with OA. However, the interaction between these environmental stressors is still poorly evaluated. In the present study, the interactive effects of seawater acidification and increasing Cu concentrations were evaluated in a zooxanthellate scleractinian coral (Mussismilia harttii), using biochemical biomarkers involved in the coral calcification process and the photosynthetic metabolism of endosymbionts. Corals were kept under control conditions (no seawater acidification and no Cu addition in seawater) or exposed to combined treatments of reduced seawater pH (8.1, 7.8, 7.5 and 7.2) and environmentally relevant concentrations of dissolved Cu (measured: 1.0, 1.6, 2.3 and 3.2 μg/L) in a mesocosm system. After 15- and 35-days exposure, corals were analyzed for photochemical efficiency (Fv/Fm), chlorophyll a content, Ca-ATPase and carbonic anhydrase (CA) activity. Results showed that 76% of the interactions between reduced seawater pH and increasing Cu concentrations were antagonistic. Only 24% of these interactions were additive or synergistic. In general, the combination of stressors had no significant deleterious effects in the photosynthetic metabolism of endosymbionts or Ca-ATPase activity. In fact, the lowest dissolved Cu concentration tested had a consistent positive effect on Ca-ATPase activity in corals facing any of the reduced seawater pH conditions tested. In turn, potentially deleterious effects on acid-base balance in M. harttii, associated with changes in CA activity, were intensified by the combination of stressors. Findings reported here indicate that Cu toxicity in future OA scenarios can be less severe than previously suggested in this coral holobiont.}, }
@article {pmid30454554, year = {2018}, author = {Kokou, F and Sasson, G and Nitzan, T and Doron-Faigenboim, A and Harpaz, S and Cnaani, A and Mizrahi, I}, title = {Host genetic selection for cold tolerance shapes microbiome composition and modulates its response to temperature.}, journal = {eLife}, volume = {7}, number = {}, pages = {}, doi = {10.7554/eLife.36398}, pmid = {30454554}, issn = {2050-084X}, support = {Grant 640384//European Research Council/International ; Grant number 1313/13//Israel Science Foundation/ ; Grant number 863-0045//Ministry of Agriculture and Rural Development/ ; }, abstract = {The hologenome concept proposes that microbes together with their hosting organism are an independent unit of selection. Motivated by this concept, we hypothesized that thermal acclimation in poikilothermic organisms is connected to their microbiome composition due to their inability to maintain their body temperature. To test this hypothesis, we used a unique experimental setup with a transgenerational selective breeding scheme for cold tolerance in tropical tilapias. We tested the effects of the selection on the gut microbiome and host transcriptomic response. Interestingly, we found that host genetic selection for thermal tolerance shapes microbiome composition and its response to cold. The microbiomes of cold-resistant fish showed higher resilience to temperature changes, indicating that the microbiome is shaped by its host's selection. These findings are consistent with the hologenome concept and highlight the connection between the host and its microbiome's response to the environment.}, }
@article {pmid30443242, year = {2018}, author = {O'Brien, PA and Smith, HA and Fallon, S and Fabricius, K and Willis, BL and Morrow, KM and Bourne, DG}, title = {Elevated CO2 Has Little Influence on the Bacterial Communities Associated With the pH-Tolerant Coral, Massive Porites spp.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2621}, doi = {10.3389/fmicb.2018.02621}, pmid = {30443242}, issn = {1664-302X}, abstract = {Ocean acidification (OA) as a result of increased anthropogenic CO2 input into the atmosphere carries consequences for all ocean life. Low pH can cause a shift in coral-associated microbial communities of pCO2-sensitive corals, however, it remains unknown whether the microbial community is also influenced in corals known to be more tolerant to high pCO2/low pH. This study profiles the bacterial communities associated with the tissues of the pCO2-tolerant coral, massive Porites spp., from two natural CO2 seep sites in Papua New Guinea. Amplicon sequencing of the hypervariable V3-V4 regions of the 16S rRNA gene revealed that microbial communities remained stable across CO2 seep sites (pH = 7.44-7.85) and adjacent control sites (ambient pH = 8.0-8.1). Microbial communities were more significantly influenced by reef location than pH, with the relative abundance of dominant microbial taxa differing between reefs. These results directly contrast with previous findings that increased CO2 has a strong effect on structuring microbial communities. The stable structure of microbial communities associated with the tissues of massive Porites spp. under high pCO2/low pH conditions confirms a high degree of tolerance by the whole Porites holobiont to OA, and suggest that pH tolerant corals such as Porites may dominate reef assemblages in an increasingly acidic ocean.}, }
@article {pmid30427096, year = {2018}, author = {Goüy de Bellocq, J and Uddin, W and Ribas, A and Bryja, J and Piálek, J and Baird, SJE}, title = {Holobiont suture zones: Parasite evidence across the European house mouse hybrid zone.}, journal = {Molecular ecology}, volume = {}, number = {}, pages = {}, doi = {10.1111/mec.14938}, pmid = {30427096}, issn = {1365-294X}, abstract = {Parasite hybrid zones resulting from host secondary contact have never been described in nature although parasite hybridization is well known and secondary contact should affect them similarly to free-living organisms. When host populations are isolated, diverge, and re-contact, intimate parasites (host specific, direct life cycle) carried during isolation will also meet and so may form parasite hybrid zones. If so, we hypothesize these should be narrower than the host's hybrid zone as shorter parasite generation time allows potentially higher divergence. We investigate multilocus genetics of two parasites across the European house mouse hybrid zone. We find each host taxon harbours its own parasite taxa. These also hybridize: parasite hybrid zones are significantly narrower than the host's. Here we show a host hybrid zone is a suture zone for a subset of its parasite community and highlight the potential of such systems as windows on the evolutionary processes of host-parasite interactions and recombinant pathogen emergence. This article is protected by copyright. All rights reserved.}, }
@article {pmid30424933, year = {2018}, author = {Castillo-Álvarez, F and Marzo-Sola, ME}, title = {Disease of the holobiont, the example of multiple sclerosis.}, journal = {Medicina clinica}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.medcli.2018.08.019}, pmid = {30424933}, issn = {1578-8989}, abstract = {In recent years there has been a revolution regarding the role of the microbiota in different diseases, most of them within the spectrum of inflammatory and autoimmune diseases, associated with the development of metagenomics and the concept of holobiont, a large organism together with its microbiota. Specifically, in Multiple Sclerosis, multiple evidence points to the role of the microbiota in experimental autoimmune encephalomyelitis, animal model of the disease, and several articles have been published in recent years about differences in intestinal microbiota among patients with multiple sclerosis and control subjects. We review in this article the concept of holobiont and the gut microbiota functions, as well as the evidence accumulated about the role of the microbiota in experimental autoimmune encephalomyelitis and multiple sclerosis. Nowadays, there is a lot of evidence showing the role of the microbiota in the genesis, prevention and treatment of experimental autoimmune encephalomyelitis based mainly on three immunological pillars, the Th1-Th17 / Th2 balance, the Treg cells and the humoral immunity. It is also well documented that there are differences in the microbiota of patients with MS that are associated with a different expression of genes related to inflammation.}, }
@article {pmid30420844, year = {2018}, author = {Galand, PE and Chapron, L and Meistertzheim, AL and Peru, E and Lartaud, F}, title = {The Effect of Captivity on the Dynamics of Active Bacterial Communities Differs Between Two Deep-Sea Coral Species.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2565}, doi = {10.3389/fmicb.2018.02565}, pmid = {30420844}, issn = {1664-302X}, abstract = {Microbes play a crucial role in sustaining the coral holobiont's functions and in particular under the pressure of environmental stressors. The effect of a changing environment on coral health is now a major branch of research that relies heavily on aquarium experiments. However, the effect of captivity on the coral microbiome remains poorly known. Here we show that different cold-water corals species have different microbiome responses to captivity. For both the DNA and the RNA fraction, Madrepora oculata bacterial communities were maintained for at least 6 months of aquarium rearing, while Lophelia pertusa bacteria changed within a day. Interestingly, bacteria from the genus Endozoicomonas, a ubiquitous symbiont of numerous marine hosts, were resilient and remained active in M. oculata for several months. Our results demonstrate that a good knowledge of the coral microbiome and an understanding of the ecological strategy of the holobiont is needed before designing aquarium experiments.}, }
@article {pmid30417121, year = {2018}, author = {Ochsenkühn, MA and Schmitt-Kopplin, P and Harir, M and Amin, SA}, title = {Coral metabolite gradients affect microbial community structures and act as a disease cue.}, journal = {Communications biology}, volume = {1}, number = {}, pages = {184}, doi = {10.1038/s42003-018-0189-1}, pmid = {30417121}, issn = {2399-3642}, abstract = {Corals are threatened worldwide due to prevalence of disease and bleaching. Recent studies suggest the ability of corals to resist disease is dependent on maintaining healthy microbiomes that span coral tissues and surfaces, the holobiont. Although our understanding of the role endosymbiotic microbes play in coral health has advanced, the role surface-associated microbes and their chemical signatures play in coral health is limited. Using minimally invasive water sampling, we show that the corals Acropora and Platygyra harbor unique bacteria and metabolites at their surface, distinctly different from surrounding seawater. The surface metabolites released by the holobiont create concentration gradients at 0-5 cm away from the coral surface. These molecules are identified as chemo-attractants, antibacterials, and infochemicals, suggesting they may structure coral surface-associated microbes. Further, we detect surface-associated metabolites characteristic of healthy or white syndrome disease infected corals, a finding which may aid in describing effects of diseases.}, }
@article {pmid30417109, year = {2018}, author = {Mazel, F and Davis, KM and Loudon, A and Kwong, WK and Groussin, M and Parfrey, LW}, title = {Is Host Filtering the Main Driver of Phylosymbiosis across the Tree of Life?.}, journal = {mSystems}, volume = {3}, number = {5}, pages = {}, doi = {10.1128/mSystems.00097-18}, pmid = {30417109}, issn = {2379-5077}, abstract = {Host-associated microbiota composition can be conserved over evolutionary time scales. Indeed, closely related species often host similar microbiota; i.e., the composition of their microbiota harbors a phylogenetic signal, a pattern sometimes referred to as &quot;phylosymbiosis.&quot; Elucidating the origins of this pattern is important to better understand microbiota ecology and evolution. However, this is hampered by our lack of theoretical expectations and a comprehensive overview of phylosymbiosis prevalence in nature. Here, we use simulations to provide a simple expectation for when we should expect this pattern to occur and then review the literature to document the prevalence and strength of phylosymbiosis across the host tree of life. We demonstrate that phylosymbiosis can readily emerge from a simple ecological filtering process, whereby a given host trait (e.g., gut pH) that varies with host phylogeny (i.e., harbors a phylogenetic signal) filters preadapted microbes. We found marked differences between methods used to detect phylosymbiosis, so we proposed a series of practical recommendations based on using multiple best-performing approaches. Importantly, we found that, while the prevalence of phylosymbiosis is mixed in nature, it appears to be stronger for microbiotas living in internal host compartments (e.g., the gut) than those living in external compartments (e.g., the rhizosphere). We show that phylosymbiosis can theoretically emerge without any intimate, long-term coevolutionary mechanisms and that most phylosymbiosis patterns observed in nature are compatible with a simple ecological process. Deviations from baseline ecological expectations might be used to further explore more complex hypotheses, such as codiversification. IMPORTANCE Phylosymbiosis is a pattern defined as the tendency of closely related species to host microbiota whose compositions resemble each other more than host species drawn at random from the same tree. Understanding the mechanisms behind phylosymbiosis is important because it can shed light on rules governing the assembly of host-associated microbiotas and, potentially, their coevolutionary dynamics with hosts. For example, is phylosymbiosis a result of coevolution, or can it be generated by simple ecological filtering processes? Beyond qualitative theoretical models, quantitative theoretical expectations can provide new insights. For example, deviations from a simple baseline of ecological filtering may be used to test more-complex hypotheses (e.g., coevolution). Here, we use simulations to provide evidence that simple host-related ecological filtering can readily generate phylosymbiosis, and we contrast these predictions with real-world data. We find that while phylosymbiosis is widespread in nature, phylosymbiosis patterns are compatible with a simple ecological model in the majority of taxa. Internal compartments of hosts, such as the animal gut, often display stronger phylosymbiosis than expected from a purely ecological filtering process, suggesting that other mechanisms are also involved.}, }
@article {pmid30413836, year = {2018}, author = {Villegas-Plazas, M and Wos-Oxley, ML and Sanchez, JA and Pieper, DH and Thomas, OP and Junca, H}, title = {Variations in Microbial Diversity and Metabolite Profiles of the Tropical Marine Sponge Xestospongia muta with Season and Depth.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1285-y}, pmid = {30413836}, issn = {1432-184X}, support = {KBBE-2009-245226//MAGICPAH/ ; 652-2014//EcosNord-Colciencias/ ; JI-2012//Jóven Investigador - Colciencias/ ; MSc scholarship//Universidad de los Andes/ ; }, abstract = {Xestospongia muta is among the most emblematic sponge species inhabiting coral reefs of the Caribbean Sea. Besides being the largest sponge species growing in the Caribbean, it is also known to produce secondary metabolites. This study aimed to assess the effect of depth and season on the symbiotic bacterial dynamics and major metabolite profiles of specimens of X. muta thriving in a tropical marine biome (Portobelo Bay, Panamá), which allow us to determine whether variability patterns are similar to those reported for subtropical latitudes. The bacterial assemblages were characterized using Illumina deep-sequencing and metabolomic profiles using UHPLC-DAD-ELSD from five depths (ranging 9-28 m) across two seasons (spring and autumn). Diverse symbiotic communities, representing 24 phyla with a predominance of Proteobacteria and Chloroflexi, were found. Although several thousands of OTUs were determined, most of them belong to the rare biosphere and only 23 to a core community. There was a significant difference between the structure of the microbial communities in respect to season (autumn to spring), with a further significant difference between depths only in autumn. This was partially mirrored in the metabolome profile, where the overall metabolite composition did not differ between seasons, but a significant depth gradient was observed in autumn. At the phyla level, Cyanobacteria, Firmicutes, Actinobacteria, and Spirochaete showed a mild-moderate correlation with the metabolome profile. The metabolomic profiles were mainly characterized by known brominated polyunsaturated fatty acids. This work presents findings about the composition and dynamics of the microbial assemblages of X. muta expanding and confirming current knowledge about its remarkable diversity and geographic variability as observed in this tropical marine biome.}, }
@article {pmid30410727, year = {2018}, author = {Morris, JJ}, title = {What is the hologenome concept of evolution?.}, journal = {F1000Research}, volume = {7}, number = {}, pages = {}, doi = {10.12688/f1000research.14385.1}, pmid = {30410727}, issn = {2046-1402}, abstract = {All multicellular organisms are colonized by microbes, but a gestalt study of the composition of microbiome communities and their influence on the ecology and evolution of their macroscopic hosts has only recently become possible. One approach to thinking about the topic is to view the host-microbiome ecosystem as a &quot;holobiont&quot;. Because natural selection acts on an organism's realized phenotype, and the phenotype of a holobiont is the result of the integrated activities of both the host and all of its microbiome inhabitants, it is reasonable to think that evolution can act at the level of the holobiont and cause changes in the &quot;hologenome&quot;, or the collective genomic content of all the individual bionts within the holobiont. This relatively simple assertion has nevertheless been controversial within the microbiome community. Here, I provide a review of recent work on the hologenome concept of evolution. I attempt to provide a clear definition of the concept and its implications and to clarify common points of disagreement.}, }
@article {pmid30405652, year = {2018}, author = {Backer, R and Rokem, JS and Ilangumaran, G and Lamont, J and Praslickova, D and Ricci, E and Subramanian, S and Smith, DL}, title = {Plant Growth-Promoting Rhizobacteria: Context, Mechanisms of Action, and Roadmap to Commercialization of Biostimulants for Sustainable Agriculture.}, journal = {Frontiers in plant science}, volume = {9}, number = {}, pages = {1473}, doi = {10.3389/fpls.2018.01473}, pmid = {30405652}, issn = {1664-462X}, abstract = {Microbes of the phytomicrobiome are associated with every plant tissue and, in combination with the plant form the holobiont. Plants regulate the composition and activity of their associated bacterial community carefully. These microbes provide a wide range of services and benefits to the plant; in return, the plant provides the microbial community with reduced carbon and other metabolites. Soils are generally a moist environment, rich in reduced carbon which supports extensive soil microbial communities. The rhizomicrobiome is of great importance to agriculture owing to the rich diversity of root exudates and plant cell debris that attract diverse and unique patterns of microbial colonization. Microbes of the rhizomicrobiome play key roles in nutrient acquisition and assimilation, improved soil texture, secreting, and modulating extracellular molecules such as hormones, secondary metabolites, antibiotics, and various signal compounds, all leading to enhancement of plant growth. The microbes and compounds they secrete constitute valuable biostimulants and play pivotal roles in modulating plant stress responses. Research has demonstrated that inoculating plants with plant-growth promoting rhizobacteria (PGPR) or treating plants with microbe-to-plant signal compounds can be an effective strategy to stimulate crop growth. Furthermore, these strategies can improve crop tolerance for the abiotic stresses (e.g., drought, heat, and salinity) likely to become more frequent as climate change conditions continue to develop. This discovery has resulted in multifunctional PGPR-based formulations for commercial agriculture, to minimize the use of synthetic fertilizers and agrochemicals. This review is an update about the role of PGPR in agriculture, from their collection to commercialization as low-cost commercial agricultural inputs. First, we introduce the concept and role of the phytomicrobiome and the agricultural context underlying food security in the 21st century. Next, mechanisms of plant growth promotion by PGPR are discussed, including signal exchange between plant roots and PGPR and how these relationships modulate plant abiotic stress responses via induced systemic resistance. On the application side, strategies are discussed to improve rhizosphere colonization by PGPR inoculants. The final sections of the paper describe the applications of PGPR in 21st century agriculture and the roadmap to commercialization of a PGPR-based technology.}, }
@article {pmid30404178, year = {2018}, author = {Pasquaretta, C and Gómez-Moracho, T and Heeb, P and Lihoreau, M}, title = {Exploring Interactions between the Gut Microbiota and Social Behavior through Nutrition.}, journal = {Genes}, volume = {9}, number = {11}, pages = {}, doi = {10.3390/genes9110534}, pmid = {30404178}, issn = {2073-4425}, support = {ANR-16-CE02-0002-01//Agence Nationale de la Recherche/ ; ANR-10-LABX-41//Laboratoire d'Excellence (LABEX)' TULIP/ ; }, abstract = {Microbes influence a wide range of host social behaviors and vice versa. So far, however, the mechanisms underpinning these complex interactions remain poorly understood. In social animals, where individuals share microbes and interact around foods, the gut microbiota may have considerable consequences on host social interactions by acting upon the nutritional behavior of individual animals. Here we illustrate how conceptual advances in nutritional ecology can help the study of these processes and allow the formulation of new empirically testable predictions. First, we review key evidence showing that gut microbes influence the nutrition of individual animals, through modifications of their nutritional state and feeding decisions. Next, we describe how these microbial influences and their social consequences can be studied by modelling populations of hosts and their gut microbiota into a single conceptual framework derived from nutritional geometry. Our approach raises new perspectives for the study of holobiont nutrition and will facilitate theoretical and experimental research on the role of the gut microbiota in the mechanisms and evolution of social behavior.}, }
@article {pmid30386791, year = {2018}, author = {Sewell, AK and Han, M and Qi, B}, title = {An unexpected benefit from E. coli: how enterobactin benefits host health.}, journal = {Microbial cell (Graz, Austria)}, volume = {5}, number = {10}, pages = {469-471}, doi = {10.15698/mic2018.10.653}, pmid = {30386791}, issn = {2311-2638}, abstract = {Iron plays many critical roles in human biology, such as aiding the transport of oxygen and mediating redox reactions. Iron is essential for life, yet little is known about how iron is taken up into mitochondria to impact the labile iron pool. Iron deficiency is one of the most prevalent human nutrient-deficiency diseases in the world and is a major cause of anemia that affects >25% of the world's population, but unfortunately the current treatment (oral iron supplementation) is inefficient and has many side effects. A greater understanding of iron uptake, and discovery of molecules that aid in this process, may lead to more effective treatments for iron deficiency. In this study, we uncovered a unique and surprising role for an Escherichia coli-produced siderophore enterobactin (Ent) that facilitates iron uptake by the host, observed in both C. elegans and mammalian cells. Although siderophores are well-known Fe+3 scavengers, this activity has previously been described to only benefit iron acquisition by bacteria, not the host. This unexpected function is dependent on the binding of Ent to the host's ATP synthase α-subunit but is independent of other subunits of the ATP synthase. This finding marks a major shift regarding the role of this siderophore in the &quot;iron tug-of-war&quot; paradigm, which is often used to describe the fight between the bacteria and the host for this essential micronutrient. Instead, this study presents E. coli as a commensal &quot;friend&quot; that provides a molecule that supports the host's iron homeostasis. This work reveals a novel, beneficial role of a bacteria-generated molecule in aiding the host's iron homeostasis, and points to surprising new benefits from commensal bacteria.}, }
@article {pmid30336184, year = {2018}, author = {Miller, WB and Torday, JS and Baluška, F}, title = {Biological Evolution as Defense of 'Self'.}, journal = {Progress in biophysics and molecular biology}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.pbiomolbio.2018.10.002}, pmid = {30336184}, issn = {1873-1732}, abstract = {Although the origin of self-referential consciousness is unknown, it can be argued that the instantiation of self-reference was the commencement the living state as phenomenal experientiality. As self-referential cognition is demonstrated by all living organisms, life can be equated with the sustenance of cellular homeostasis in the continuous defense of 'self'. It is proposed that the epicenter of 'self' is perpetually embodied within the basic cellular form in which it was instantiated. Cognition-Based Evolution argues that all of biological and evolutionary development represents the perpetual autopoietic defense of self-referential basal cellular states of homeostatic preference. The means by which these states are attained and maintained is through self-referential measurement of information and its communication. The multicellular forms, either as biofilms or holobionts, represent the cellular attempt to achieve maximum states of informational distinction and energy efficiency through individual and collective means. In this frame, consciousness, self-consciousness and intelligence can be identified as forms of collective cellular phenotype directed towards the defense of fundamental cellular self-reference.}, }
@article {pmid30328280, year = {2018}, author = {Thomashow, LS and LeTourneau, MK and Kwak, YS and Weller, DM}, title = {The soil-borne legacy in the age of the holobiont.}, journal = {Microbial biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1751-7915.13325}, pmid = {30328280}, issn = {1751-7915}, abstract = {Future efforts to increase agricultural productivity will focus on crops as functional units comprised of plants and their associated microflora in the context of the various environments in which they are grown. It is suggested that future efforts to increase agricultural productivity will focus on crops as functional units comprised of plants and their associated beneficial microorganisms in the context in which they are grown. Scientists, industry, and farmers must work closely together to develop, adapt, and apply new technologies to a wide range of cropping systems. Consumer education is needed help grow public awareness that 'plant probiotics' offer a safe and environmentally friendly alternative to dependence on the use of chemical pesticides.}, }
@article {pmid30311675, year = {2018}, author = {Leftwich, PT and Hutchings, MI and Chapman, T}, title = {Diet, Gut Microbes and Host Mate Choice: Understanding the significance of microbiome effects on host mate choice requires a case by case evaluation.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {}, number = {}, pages = {}, doi = {10.1002/bies.201800053}, pmid = {30311675}, issn = {1521-1878}, support = {BB/K000489/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, abstract = {All organisms live in close association with microbes. However, not all such associations are meaningful in an evolutionary context. Current debate concerns whether hosts and microbes are best described as communities of individuals or as holobionts (selective units of hosts plus their microbes). Recent reports that assortative mating of hosts by diet can be mediated by commensal gut microbes have attracted interest as a potential route to host reproductive isolation (RI). Here, the authors discuss logical problems with this line of argument. The authors briefly review how microbes can affect host mating preferences and evaluate recent findings from fruitflies. Endosymbionts can potentially influence host RI given stable and recurrent co-association of hosts and microbes over evolutionary time. However, observations of co-occurrence of microbes and hosts are ripe for misinterpretation and such associations will rarely represent a meaningful holobiont. A framework in which hosts and their microbes are independent evolutionary units provides the only satisfactory explanation for the observed range of effects and associations.}, }
@article {pmid30310167, year = {2018}, author = {Cernava, T and Aschenbrenner, IA and Soh, J and Sensen, CW and Grube, M and Berg, G}, title = {Plasticity of a holobiont: desiccation induces fasting-like metabolism within the lichen microbiota.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-018-0286-7}, pmid = {30310167}, issn = {1751-7370}, support = {I882//Austrian Science Fund (FWF Der Wissenschaftsfonds)/ ; I882//Austrian Science Fund (FWF Der Wissenschaftsfonds)/ ; }, abstract = {The role of host-associated microbiota in enduring dehydration and drought is largely unknown. We have used lichens to study this increasingly important problem because they are the organisms that are optimally adapted to reoccurring hydration/dehydration cycles, and they host a defined and persistent bacterial community. The analysis of metatranscriptomic datasets from bacterial communities of the lung lichen (Lobaria pulmonaria (L.) Hoffm.), sampled under representative hydration stages, revealed significant structural shifts and functional specialization to host conditions. The hydrated samples showed upregulated transcription of transport systems, tRNA modification and various porins (Omp2b by Rhizobiales), whereas the desiccated samples showed different functions related to stress adaption prominently. Carbohydrate metabolism was activated under both conditions. Under dry conditions, upregulation of a specialized ketone metabolism indicated a switch to lipid-based nutrition. Several bacterial lineages were involved in a functional transition that was reminiscent of a 'fasting metaorganism'. Similar functional adaptions were assigned to taxonomically unrelated groups, indicating hydration-related specialization of the microbiota. We were able to show that host-associated bacterial communities are well adapted to dehydration by stress protection and changes of the metabolism. Moreover, our results indicate an intense interplay in holobiont functioning under drought stress.}, }
@article {pmid30309375, year = {2018}, author = {Zepeda Mendoza, ML and Roggenbuck, M and Manzano Vargas, K and Hansen, LH and Brunak, S and Gilbert, MTP and Sicheritz-Pontén, T}, title = {Protective role of the vulture facial skin and gut microbiomes aid adaptation to scavenging.}, journal = {Acta veterinaria Scandinavica}, volume = {60}, number = {1}, pages = {61}, doi = {10.1186/s13028-018-0415-3}, pmid = {30309375}, issn = {1751-0147}, support = {R52-A5062//Lundbeckfonden/ ; }, abstract = {BACKGROUND: Vultures have adapted the remarkable ability to feed on carcasses that may contain microorganisms that would be pathogenic to most other animals. The holobiont concept suggests that the genetic basis of such adaptation may not only lie within their genomes, but additionally in their associated microbes. To explore this, we generated shotgun DNA sequencing datasets of the facial skin and large intestine microbiomes of the black vulture (Coragyps atratus) and the turkey vulture (Cathartes aura). We characterized the functional potential and taxonomic diversity of their microbiomes, the potential pathogenic challenges confronted by vultures, and the microbial taxa and genes that could play a protective role on the facial skin and in the gut.<br><br>RESULTS: We found microbial taxa and genes involved in diseases, such as dermatitis and pneumonia (more abundant on the facial skin), and gas gangrene and food poisoning (more abundant in the gut). Interestingly, we found taxa and functions with potential for playing beneficial roles, such as antilisterial bacteria in the gut, and genes for the production of antiparasitics and insecticides on the facial skin. Based on the identified phages, we suggest that phages aid in the control and possibly elimination, as in phage therapy, of microbes reported as pathogenic to a variety of species. Interestingly, we identified Adineta vaga in the gut, an invertebrate that feeds on dead bacteria and protozoans, suggesting a defensive predatory mechanism. Finally, we suggest a colonization resistance role through biofilm formation played by Fusobacteria and Clostridia in the gut.<br><br>CONCLUSIONS: Our results highlight the importance of complementing genomic analyses with metagenomics in order to obtain a clearer understanding of the host-microbial alliance and show the importance of microbiome-mediated health protection for adaptation to extreme diets, such as scavenging.}, }
@article {pmid30305166, year = {2018}, author = {Guyomar, C and Legeai, F and Jousselin, E and Mougel, C and Lemaitre, C and Simon, JC}, title = {Multi-scale characterization of symbiont diversity in the pea aphid complex through metagenomic approaches.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {181}, doi = {10.1186/s40168-018-0562-9}, pmid = {30305166}, issn = {2049-2618}, abstract = {BACKGROUND: Most metazoans are involved in durable relationships with microbes which can take several forms, from mutualism to parasitism. The advances of NGS technologies and bioinformatics tools have opened opportunities to shed light on the diversity of microbial communities and to give some insights into the functions they perform in a broad array of hosts. The pea aphid is a model system for the study of insect-bacteria symbiosis. It is organized in a complex of biotypes, each adapted to specific host plants. It harbors both an obligatory symbiont supplying key nutrients and several facultative symbionts bringing additional functions to the host, such as protection against biotic and abiotic stresses. However, little is known on how the symbiont genomic diversity is structured at different scales: across host biotypes, among individuals of the same biotype, or within individual aphids, which limits our understanding on how these multi-partner symbioses evolve and interact.<br><br>RESULTS: We present a framework well adapted to the study of genomic diversity and evolutionary dynamics of the pea aphid holobiont from metagenomic read sets, based on mapping to reference genomes and whole genome variant calling. Our results revealed that the pea aphid microbiota is dominated by a few heritable bacterial symbionts reported in earlier works, with no discovery of new microbial associates. However, we detected a large and heterogeneous genotypic diversity associated with the different symbionts of the pea aphid. Partitioning analysis showed that this fine resolution diversity is distributed across the three considered scales. Phylogenetic analyses highlighted frequent horizontal transfers of facultative symbionts between host lineages, indicative of flexible associations between the pea aphid and its microbiota. However, the evolutionary dynamics of symbiotic associations strongly varied depending on the symbiont, reflecting different histories and possible constraints. In addition, at the intra-host scale, we showed that different symbiont strains may coexist inside the same aphid host.<br><br>CONCLUSIONS: We present a methodological framework for the detailed analysis of NGS data from microbial communities of moderate complexity and gave major insights into the extent of diversity in pea aphid-symbiont associations and the range of evolutionary trajectories they could take.}, }
@article {pmid30301849, year = {2018}, author = {Hernandez-Agreda, A and Leggat, W and Bongaerts, P and Herrera, C and Ainsworth, TD}, title = {Rethinking the Coral Microbiome: Simplicity Exists within a Diverse Microbial Biosphere.}, journal = {mBio}, volume = {9}, number = {5}, pages = {}, doi = {10.1128/mBio.00812-18}, pmid = {30301849}, issn = {2150-7511}, abstract = {Studies of the coral microbiome predominantly characterize the microbial community of the host species as a collective, rather than that of the individual. This ecological perspective on the coral microbiome has led to the conclusion that the coral holobiont is the most diverse microbial biosphere studied thus far. However, investigating the microbiome of the individual, rather than that of the species, highlights common and conserved community attributes which can provide insights into the significance of microbial associations to the host. Here, we show there are consistent characteristics between individuals in the proposed three components of the coral microbiome (i.e., &quot;environmentally responsive community,&quot; &quot;resident or individual microbiome,&quot; and &quot;core microbiome&quot;). We found that the resident microbiome of a photoendosymbiotic coral harbored <3% (∼605 phylotypes) of the 16S rRNA phylotypes associated with all investigated individuals of that species (&quot;species-specific microbiome&quot;) (∼21,654 phylotypes; individuals from Pachyseris speciosa [n = 123], Mycedium elephantotus [n = 95], and Acropora aculeus [n = 91] from 10 reef locations). The remaining bacterial phylotypes (>96%) (environmentally responsive community) of the species-specific microbiome were in fact not found in association with the majority of individuals of the species. Only 0.1% (∼21 phylotypes) of the species-specific microbiome of each species was shared among all individuals of the species (core microbiome), equating to ∼3.4% of the resident microbiome. We found taxonomic redundancy and consistent patterns of composition, structure, and taxonomic breadth across individual microbiomes from the three coral species. Our results demonstrate that the coral microbiome is structured at the individual level.IMPORTANCE We propose that the coral holobiont should be conceptualized as a diverse transient microbial community that is responsive to the surrounding environment and encompasses a simple, redundant, resident microbiome and a small conserved core microbiome. Most importantly, we show that the coral microbiome is comparable to the microbiomes of other organisms studied thus far. Accurately characterizing the coral-microbe interactions provides an important baseline from which the functional roles and the functional niches within which microbes reside can be deciphered.}, }
@article {pmid30286722, year = {2018}, author = {Mancini, MV and Damiani, C and Accoti, A and Tallarita, M and Nunzi, E and Cappelli, A and Bozic, J and Catanzani, R and Rossi, P and Valzano, M and Serrao, A and Ricci, I and Spaccapelo, R and Favia, G}, title = {Estimating bacteria diversity in different organs of nine species of mosquito by next generation sequencing.}, journal = {BMC microbiology}, volume = {18}, number = {1}, pages = {126}, doi = {10.1186/s12866-018-1266-9}, pmid = {30286722}, issn = {1471-2180}, support = {Prin 2012-2012T85B3R//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; PRIN 2015-JXC3JF//Ministero dell'Istruzione, dell'Università e della Ricerca/ ; FAR2015//Università di Camerino/ ; }, abstract = {BACKGROUND: Symbiosis in insects is accumulating significant amount of studies: the description of a wide array of mutualistic associations across the evolutionary history of insects suggests that resident microbiota acts as a driving force by affecting several aspects of hosts biology. Among arthropods, mosquito midgut microbiota has been largely investigated, providing crucial insights on the role and implications of host-symbiont relationships. However, limited amount of studies addressed their efforts on the investigation of microbiota colonizing salivary glands and reproductive tracts, crucial organs for pathogen invasion and vertical transmission of symbiotic microorganisms. Using 16S rRNA gene sequencing-based approach, we analysed the microbiota of gut, salivary glands and reproductive tracts of several mosquito species, representing some of the main vectors of diseases, aiming at describing the dynamics of bacterial communities within the individual.<br><br>RESULTS: We identified a shared core microbiota between different mosquito species, although interesting inter- and intra-species differences were detected. Additionally, our results showed deep divergences between genera, underlining microbiota specificity and adaptation to their host.<br><br>CONCLUSIONS: The comprehensive landscape of the bacterial microbiota components may ultimately provide crucial insights and novel targets for possible application of symbionts in innovative strategies for the control of vector borne diseases, globally named Symbiotic Control (SC), and suggesting that the holobiont of different mosquito species may significantly vary. Moreover, mosquito species are characterized by distinctive microbiota in different organs, likely reflecting different functions and/or adaptation processes.}, }
@article {pmid30271972, year = {2018}, author = {Palmer, CV}, title = {Immunity and the coral crisis.}, journal = {Communications biology}, volume = {1}, number = {}, pages = {91}, doi = {10.1038/s42003-018-0097-4}, pmid = {30271972}, issn = {2399-3642}, abstract = {Climate change is killing coral at an unprecedented rate. As immune systems promote homeostasis and survival of adverse conditions I propose we explore coral health in the context of holobiont immunity.}, }
@article {pmid30255826, year = {2018}, author = {Løvendahl, P and Difford, GF and Li, B and Chagunda, MGG and Huhtanen, P and Lidauer, MH and Lassen, J and Lund, P}, title = {Review: Selecting for improved feed efficiency and reduced methane emissions in dairy cattle.}, journal = {Animal : an international journal of animal bioscience}, volume = {}, number = {}, pages = {1-14}, doi = {10.1017/S1751731118002276}, pmid = {30255826}, issn = {1751-732X}, abstract = {It may be possible for dairy farms to improve profitability and reduce environmental impacts by selecting for higher feed efficiency and lower methane (CH4) emission traits. It remains to be clarified how CH4 emission and feed efficiency traits are related to each other, which will require direct and accurate measurements of both of these traits in large numbers of animals under the conditions in which they are expected to perform. The ranking of animals for feed efficiency and CH4 emission traits can differ depending upon the type and duration of measurement used, the trait definitions and calculations used, the period in lactation examined and the production system, as well as interactions among these factors. Because the correlation values obtained between feed efficiency and CH4 emission data are likely to be biased when either or both are expressed as ratios, therefore researchers would be well advised to maintain weighted components of the ratios in the selection index. Nutrition studies indicate that selecting low emitting animals may result in reduced efficiency of cell wall digestion, that is NDF, a key ruminant characteristic in human food production. Moreover, many interacting biological factors that are not measured directly, including digestion rate, passage rate, the rumen microbiome and rumen fermentation, may influence feed efficiency and CH4 emission. Elucidating these mechanisms may improve dairy farmers ability to select for feed efficiency and reduced CH4 emission.}, }
@article {pmid30249182, year = {2018}, author = {Cavalcanti, GS and Shukla, P and Morris, M and Ribeiro, B and Foley, M and Doane, MP and Thompson, CC and Edwards, MS and Dinsdale, EA and Thompson, FL}, title = {Rhodoliths holobionts in a changing ocean: host-microbes interactions mediate coralline algae resilience under ocean acidification.}, journal = {BMC genomics}, volume = {19}, number = {1}, pages = {701}, doi = {10.1186/s12864-018-5064-4}, pmid = {30249182}, issn = {1471-2164}, abstract = {BACKGROUND: Life in the ocean will increasingly have to contend with a complex matrix of concurrent shifts in environmental properties that impact their physiology and control their life histories. Rhodoliths are coralline red algae (Corallinales, Rhodophyta) that are photosynthesizers, calcifiers, and ecosystem engineers and therefore represent important targets for ocean acidification (OA) research. Here, we exposed live rhodoliths to near-future OA conditions to investigate responses in their photosynthetic capacity, calcium carbonate production, and associated microbiome using carbon uptake, decalcification assays, and whole genome shotgun sequencing metagenomic analysis, respectively. The results from our live rhodolith assays were compared to similar manipulations on dead rhodolith (calcareous skeleton) biofilms and water column microbial communities, thereby enabling the assessment of host-microbiome interaction under climate-driven environmental perturbations.<br><br>RESULTS: Under high pCO2 conditions, live rhodoliths exhibited positive physiological responses, i.e. increased photosynthetic activity, and no calcium carbonate biomass loss over time. Further, whereas the microbiome associated with live rhodoliths remained stable and resembled a healthy holobiont, the microbial community associated with the water column changed after exposure to elevated pCO2.<br><br>CONCLUSIONS: Our results suggest that a tightly regulated microbial-host interaction, as evidenced by the stability of the rhodolith microbiome recorded here under OA-like conditions, is important for host resilience to environmental stress. This study extends the scarce comprehension of microbes associated with rhodolith beds and their reaction to increased pCO2, providing a more comprehensive approach to OA studies by assessing the host holobiont.}, }
@article {pmid30238406, year = {2018}, author = {Stencel, A and Wloch-Salamon, DM}, title = {Correction to: Some theoretical insights into the hologenome theory of evolution and the role of microbes in speciation.}, journal = {Theory in biosciences = Theorie in den Biowissenschaften}, volume = {}, number = {}, pages = {}, doi = {10.1007/s12064-018-0270-9}, pmid = {30238406}, issn = {1611-7530}, abstract = {The original version of this article unfortunately contained a mistake.}, }
@article {pmid30233528, year = {2018}, author = {Clerissi, C and Brunet, S and Vidal-Dupiol, J and Adjeroud, M and Lepage, P and Guillou, L and Escoubas, JM and Toulza, E}, title = {Protists Within Corals: The Hidden Diversity.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {2043}, doi = {10.3389/fmicb.2018.02043}, pmid = {30233528}, issn = {1664-302X}, abstract = {Previous observations suggested that microbial communities contribute to coral health and the ecological resilience of coral reefs. However, most studies of coral microbiology focused on prokaryotes and the endosymbiotic algae Symbiodinium. In contrast, knowledge concerning diversity of other protists is still lacking, possibly due to methodological constraints. As most eukaryotic DNA in coral samples was derived from hosts, protist diversity was missed in metagenome analyses. To tackle this issue, we designed blocking primers for Scleractinia sequences amplified with two primer sets that targeted variable loops of the 18S rRNA gene (18SV1V2 and 18SV4). These blocking primers were used on environmental colonies of Pocillopora damicornis sensu lato from two regions with contrasting thermal regimes (Djibouti and New Caledonia). In addition to Symbiodinium clades A/C/D, Licnophora and unidentified coccidia genera were found in many samples. In particular, coccidian sequences formed a robust monophyletic clade with other protists identified in Agaricia, Favia, Montastraea, Mycetophyllia, Porites, and Siderastrea coral colonies. Moreover, Licnophora and coccidians had different distributions between the two geographic regions. A similar pattern was observed between Symbiodinium clades C and A/D. Although we were unable to identify factors responsible for this pattern, nor were we able to confirm that these taxa were closely associated with corals, we believe that these primer sets and the associated blocking primers offer new possibilities to describe the hidden diversity of protists within different coral species.}, }
@article {pmid30224089, year = {2018}, author = {Carthey, AJR and Gillings, MR and Blumstein, DT}, title = {The Extended Genotype: Microbially Mediated Olfactory Communication.}, journal = {Trends in ecology &amp; evolution}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.tree.2018.08.010}, pmid = {30224089}, issn = {1872-8383}, abstract = {Microbes are now known to influence inter- and intraspecific olfactory signaling systems. They do so by producing metabolites that function as odorants. A unique attribute of such odorants is that they arise as a product of microbial-host interactions. These interactions need not be mutualistic, and indeed can be antagonistic. We develop an integrated ecoevolutionary model to explore microbially mediated olfactory communication and a process model that illustrates the various ways that microbial products might contribute to odorants. This novel approach generates testable predictions, including that selection to incorporate microbial products should be a common feature of infochemicals that communicate identity but not those that communicate fitness or quality. Microbes extend an individual's genotype, but also enhance vulnerability to environmental change.}, }
@article {pmid30223906, year = {2018}, author = {Bredon, M and Dittmer, J and Noël, C and Moumen, B and Bouchon, D}, title = {Lignocellulose degradation at the holobiont level: teamwork in a keystone soil invertebrate.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {162}, doi = {10.1186/s40168-018-0536-y}, pmid = {30223906}, issn = {2049-2618}, abstract = {BACKGROUND: Woodlice are recognized as keystone species in terrestrial ecosystems due to their role in the decomposition of organic matter. Thus, they contribute to lignocellulose degradation and nutrient cycling in the environment together with other macroarthropods. Lignocellulose is the main component of plants and is composed of cellulose, lignin and hemicellulose. Its digestion requires the action of multiple Carbohydrate-Active enZymes (called CAZymes), typically acting together as a cocktail with complementary, synergistic activities and modes of action. Some invertebrates express a few endogenous lignocellulose-degrading enzymes but in most species, an efficient degradation and digestion of lignocellulose can only be achieved through mutualistic associations with endosymbionts. Similar to termites, it has been suspected that several bacterial symbionts may be involved in lignocellulose degradation in terrestrial isopods, by completing the CAZyme repertoire of their hosts.<br><br>RESULTS: To test this hypothesis, host transcriptomic and microbiome shotgun metagenomic datasets were obtained and investigated from the pill bug Armadillidium vulgare. Many genes of bacterial and archaeal origin coding for CAZymes were identified in the metagenomes of several host tissues and the gut content of specimens from both laboratory lineages and a natural population of A. vulgare. Some of them may be involved in the degradation of cellulose, hemicellulose, and lignin. Reconstructing a lignocellulose-degrading microbial community based on the prokaryotic taxa contributing relevant CAZymes revealed two taxonomically distinct but functionally redundant microbial communities depending on host origin. In parallel, endogenous CAZymes were identified from the transcriptome of the host and their expression in digestive tissues was demonstrated by RT-qPCR, demonstrating a complementary enzyme repertoire for lignocellulose degradation from both the host and the microbiome in A. vulgare.<br><br>CONCLUSIONS: Our results provide new insights into the role of the microbiome in the evolution of terrestrial isopods and their adaptive radiation in terrestrial habitats.}, }
@article {pmid30223892, year = {2018}, author = {Sitaraman, R}, title = {Prokaryotic horizontal gene transfer within the human holobiont: ecological-evolutionary inferences, implications and possibilities.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {163}, doi = {10.1186/s40168-018-0551-z}, pmid = {30223892}, issn = {2049-2618}, abstract = {The ubiquity of horizontal gene transfer in the living world, especially among prokaryotes, raises interesting and important scientific questions regarding its effects on the human holobiont i.e., the human and its resident bacterial communities considered together as a unit of selection. Specifically, it would be interesting to determine how particular gene transfer events have influenced holobiont phenotypes in particular ecological niches and, conversely, how specific holobiont phenotypes have influenced gene transfer events. In this synthetic review, we list some notable and recent discoveries of horizontal gene transfer among the prokaryotic component of the human microbiota, and analyze their potential impact on the holobiont from an ecological-evolutionary viewpoint. Finally, the human-Helicobacter pylori association is presented as an illustration of these considerations, followed by a delineation of unresolved questions and avenues for future research.}, }
@article {pmid30218130, year = {2018}, author = {Bernasconi, R and Stat, M and Koenders, A and Huggett, MJ}, title = {Global Networks of Symbiodinium-Bacteria Within the Coral Holobiont.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1255-4}, pmid = {30218130}, issn = {1432-184X}, abstract = {Scleractinian corals form the framework of coral reefs and host abundant and diverse microbial communities that are fundamental to their success. A very limited number of studies have examined the co-occurrence of multiple partners within the coral 'holobiont' and their pattern of specificity over different geographical scales. In this study, we explored two molecular sequence datasets representing associations between corals and dinoflagellates in the genus Symbiodinium and between corals and bacteria, across the globe. Through a network theory approach, we characterised patterns of co-occurrences between bacteria and Symbiodinium with 13 coral genera across six water basins. The majority of the bacteria-Symbiodinium co-occurrences were specific to either a coral genus or water basin, emphasising both coral host and environment as important factors driving the diversity of coral assemblages. Yet, results also identified bacteria and Symbiodinium that were shared by multiple coral genera across several water basins. The analyses indicate that shared co-occurrences are independent of the phylogenetic and biogeographic relationship of coral hosts.}, }
@article {pmid30157257, year = {2018}, author = {Wenzel, MA and Douglas, A and Piertney, SB}, title = {Microbiome composition within a sympatric species complex of intertidal isopods (Jaera albifrons).}, journal = {PloS one}, volume = {13}, number = {8}, pages = {e0202212}, doi = {10.1371/journal.pone.0202212}, pmid = {30157257}, issn = {1932-6203}, abstract = {The increasingly recognised effects of microbiomes on the eco-evolutionary dynamics of their hosts are promoting a view of the &quot;hologenome&quot; as an integral host-symbiont evolutionary entity. For example, sex-ratio distorting reproductive parasites such as Wolbachia are well-studied pivotal drivers of invertebrate reproductive processes, and more recent work is highlighting novel effects of microbiome assemblages on host mating behaviour and developmental incompatibilities that underpin or reinforce reproductive isolation processes. However, examining the hologenome and its eco-evolutionary effects in natural populations is challenging because microbiome composition is considerably influenced by environmental factors. Here we illustrate these challenges in a sympatric species complex of intertidal isopods (Jaera albifrons spp.) with pervasive sex-ratio distortion and ecological and behavioural reproductive isolation mechanisms. We deep-sequence the bacterial 16S rRNA gene among males and females collected in spring and summer from two coasts in north-east Scotland, and examine microbiome composition with a particular focus on reproductive parasites. Microbiomes of all species were diverse (overall 3,317 unique sequences among 3.8 million reads) and comprised mainly Proteobacteria and Bacteroidetes taxa typical of the marine intertidal zone, in particular Vibrio spp. However, we found little evidence of the reproductive parasites Wolbachia, Rickettsia, Spiroplasma and Cardinium, suggesting alternative causes of sex-ratio distortion. Notwithstanding, a significant proportion of the variance in microbiome composition among samples was explained by sex (14.1 %), nested within geographic (26.9 %) and seasonal (39.6 %) variance components. The functional relevance of this sex signal was difficult to ascertain given the absence of reproductive parasites, the ephemeral nature of the species assemblages and substantial environmental variability. These results establish the Jaera albifrons species complex as an intriguing system for examining the effects of microbiomes on reproductive processes and speciation, and highlight the difficulties associated with snapshot assays of microbiome composition in dynamic and complex environments.}, }
@article {pmid30156020, year = {2018}, author = {Basso, V and De Freitas Pereira, M and Maillard, F and Mallerman, J and Mangeot-Peter, L and Zhang, F and Bonnot, C}, title = {Facing global change: the millennium challenge for plant scientists: 41st New Phytologist Symposium 'Plant sciences for the future', Nancy, France, April 2018.}, journal = {The New phytologist}, volume = {220}, number = {1}, pages = {25-29}, doi = {10.1111/nph.15376}, pmid = {30156020}, issn = {1469-8137}, }
@article {pmid30146755, year = {2018}, author = {Allard, SM and Ottesen, AR and Brown, EW and Micallef, SA}, title = {Insect exclusion limits variation in bacterial microbiomes of tomato flowers and fruit.}, journal = {Journal of applied microbiology}, volume = {}, number = {}, pages = {}, doi = {10.1111/jam.14087}, pmid = {30146755}, issn = {1365-2672}, abstract = {AIMS: The effect of insect exclusion via netting on bacterial microbiota associated with field-grown tomato fruit and flowers was evaluated.<br><br>METHODS AND RESULTS: Amplicon-based bacterial community profiling from insect-exposed plants and plants wrapped in nylon mosquito netting was conducted on total DNA extracted from tomato flower and mature unripe fruit washes. The V1-V3 region of the 16S rRNA gene was sequenced using Illumina MiSeq and analyzed using QIIME v1.8. The carposphere supported significantly more phylogenetic diversity compared to the anthosphere, as measured by Operational Taxonomic Unit (OTU) richness (p=0.001) and Faith's Phylogenetic Diversity (p=0.004). Flowers and fruit hosted distinct bacterial community structures (R2 =0.27, p=0.001), with specific taxonomic differences in taxa that included the Xanthomonadaceae (higher in flowers), and the Pseudomonadaceae, Methylobacteriaceae and Rhizobiales (higher in fruit) (FDR-p<0.05). Bacterial community profiles of netted plants were overall statistically similar to non-netted plants for both flowers and fruit (p>0.10). However, less variation between samples was observed among flowers (~50% less, p=0.004) and green fruit (~10% less, p=0.038) collected from netted than non-netted plants.<br><br>CONCLUSION: Insects may introduce or augment variability in bacterial diversity associated with tomato flowers and potentially green fruit surfaces.<br><br>This work contributes to knowledge on microbiome dynamics of the tomato holobiont. Deciphering drivers of bacterial diversity and community structure of fruit crops could reveal processes important to agricultural management, such as competitive exclusion of pathogens and priming of plant defense mechanisms. This article is protected by copyright. All rights reserved.}, }
@article {pmid30142922, year = {2018}, author = {Stabili, L and Parisi, MG and Parrinello, D and Cammarata, M}, title = {Cnidarian Interaction with Microbial Communities: From Aid to Animal's Health to Rejection Responses.}, journal = {Marine drugs}, volume = {16}, number = {9}, pages = {}, doi = {10.3390/md16090296}, pmid = {30142922}, issn = {1660-3397}, abstract = {The phylum Cnidaria is an ancient branch in the tree of metazoans. Several species exert a remarkable longevity, suggesting the existence of a developed and consistent defense mechanism of the innate immunity capable to overcome the potential repeated exposure to microbial pathogenic agents. Increasing evidence indicates that the innate immune system in Cnidarians is not only involved in the disruption of harmful microorganisms, but also is crucial in structuring tissue-associated microbial communities that are essential components of the Cnidarian holobiont and useful to the animal's health for several functions, including metabolism, immune defense, development, and behavior. Sometimes, the shifts in the normal microbiota may be used as &quot;early&quot; bio-indicators of both environmental changes and/or animal disease. Here the Cnidarians relationships with microbial communities and the potential biotechnological applications are summarized and discussed.}, }
@article {pmid30128208, year = {2018}, author = {Van Duyl, FC and Mueller, B and Meesters, EH}, title = {Spatio-temporal variation in stable isotope signatures (δ13C and δ15N) of sponges on the Saba Bank.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e5460}, doi = {10.7717/peerj.5460}, pmid = {30128208}, issn = {2167-8359}, abstract = {Sponges are ubiquitous on coral reefs, mostly long lived and therefore adaptive to changing environmental conditions. They feed on organic matter withdrawn from the passing water and they may harbor microorganisms (endosymbionts), which contribute to their nutrition. Their diets and stable isotope (SI) fractionation determine the SI signature of the sponge holobiont. Little is known of spatio-temporal variations in SI signatures of δ13C and δ15N in tropical sponges and whether they reflect variations in the environment. We investigated the SI signatures of seven common sponge species with different functional traits and their potential food sources between 15 and 32 m depth along the S-SE and E-NE side of the Saba Bank, Eastern Caribbean, in October 2011 and October 2013. SI signatures differed significantly between most sponge species, both in mean values and in variation, indicating different food preferences and/or fractionation, inferring sponge species-specific isotopic niche spaces. In 2011, all sponge species at the S-SE side were enriched in d13C compared to the E-NE side. In 2013, SI signatures of sponges did not differ between the two sides and were overall lighter in δ13C and δ15N than in 2011. Observed spatio-temporal changes in SI in sponges could not be attributed to changes in the SI signatures of their potential food sources, which remained stable with different SI signatures of pelagic (particulate organic matter (POM): δ13C -24.9‰, δ15N +4.3‰) and benthic-derived food (macroalgae: δ13C -15.4‰, δ15N +0.8‰). Enriched δ13C signatures in sponges at the S-SE side in 2011 are proposed to be attributed to predominantly feeding on benthic-derived C. This interpretation was supported by significant differences in water mass constituents between sides in October 2011. Elevated NO3 and dissolved organic matter concentrations point toward a stronger reef signal in reef overlying water at the S-SE than N-NE side of the Bank in 2011. The depletions of δ13C and δ15N in sponges in October 2013 compared to October 2011 concurred with significantly elevated POM concentrations. The contemporaneous decrease in δ15N suggests that sponges obtain their N mostly from benthic-derived food with a lower δ15N than pelagic food. Average proportional feeding on available sources varied between sponge species and ranged from 20% to 50% for benthic and 50% to 80% for pelagic-derived food, assuming trophic enrichment factors of 0.5‰ ± sd 0.5 for δ13C and 3‰ ± sd 0.5 for δ15N for sponges. We suggest that observed variation of SI in sponges between sides and years were the result of shifts in the proportion of ingested benthic- and pelagic-derived organic matter driven by environmental changes. We show that sponge SI signatures reflect environmental variability in space and time on the Saba Bank and that SI of sponges irrespective of their species-specific traits move in a similar direction in response to these environmental changes.}, }
@article {pmid30084239, year = {2018}, author = {Kranabetter, JM and Harman-Denhoed, R and Hawkins, BJ}, title = {Saprotrophic and ectomycorrhizal fungal sporocarp stoichiometry (C : N : P) across temperate rainforests as evidence of shared nutrient constraints among symbionts.}, journal = {The New phytologist}, volume = {}, number = {}, pages = {}, doi = {10.1111/nph.15380}, pmid = {30084239}, issn = {1469-8137}, abstract = {Quantifying nutritional dynamics of free-living saprotrophs and symbiotic ectomycorrhizal fungi in the field is challenging, but the stoichiometry of fruiting bodies (sporocarps) may be an effective methodology for this purpose. Carbon (C), nitrogen (N) and phosphorus (P) concentrations of soils, foliage and 146 sporocarp collections were analyzed from 14 Pseudotsuga menziesii var. menziesii stands across a podzolization gradient on Vancouver Island (Canada). N and P concentrations were considerably higher in saprotrophic fungi. Fungal N% increased with soil N content at a greater rate for saprotrophs than ectomycorrhizal fungi, while fungal P% of saprotrophs was more constrained. Fungal N : P was more responsive to soil N : P for ectomycorrhizal fungi (homeostatic regulation coefficient 'H' = 2.9) than saprotrophs (H = 5.9), while N : P of ectomycorrhizal fungi and host tree foliage scaled almost identically. Results underscore the role of ectomycorrhizal fungi as nutrient conduits, supporting host trees, whereas saprotrophs maintain a greater degree of nutritional homeostasis. Site nutrient constraints were shared in equal measure between ectomycorrhizal fungi and host trees, particularly for P, suggesting neither partner benefits from enhanced nutrition at the expense of the other. Sporocarp stoichiometry provides new insights into mycorrhizal relationships and illustrates pervasive P deficiencies across temperate rainforests of the Pacific Northwest.}, }
@article {pmid30083934, year = {2018}, author = {Godoy-Vitorino, F and Toledo-Hernandez, C}, title = {Reef-Building Corals as a Tool for Climate Change Research in the Genomics Era.}, journal = {Results and problems in cell differentiation}, volume = {65}, number = {}, pages = {529-546}, doi = {10.1007/978-3-319-92486-1_23}, pmid = {30083934}, issn = {0080-1844}, abstract = {Coral reef ecosystems are among the most biodiverse habitats in the marine realm. They not only contribute with a plethora of ecosystem services, but they also are beneficial to humankind via nurturing marine fisheries and sustaining recreational activities. We will discuss the biology of coral reefs and their ecophysiology including the complex bacterial microbiota associated with them.}, }
@article {pmid30066215, year = {2018}, author = {Stencel, A and Wloch-Salamon, DM}, title = {Some theoretical insights into the hologenome theory of evolution and the role of microbes in speciation.}, journal = {Theory in biosciences = Theorie in den Biowissenschaften}, volume = {}, number = {}, pages = {}, doi = {10.1007/s12064-018-0268-3}, pmid = {30066215}, issn = {1611-7530}, support = {2018/28/T/HS1/00201//Narodowe Centrum Nauki/ ; Opus 2017/25/B/NZ8/01035//Narodowe Centrum Nauki/ ; DS/762 - K/ZDS/007338//Uniwersytet Jagielloński w Krakowie/ ; }, abstract = {Research on symbiotic communities (microbiomes) of multicellular organisms seems to be changing our understanding of how species of plants and animals have evolved over millions of years. The quintessence of these discoveries is the emergence of the hologenome theory of evolution, founded on the concept that a holobiont (a host along with all of its associated symbiotic microorganisms) acts a single unit of selection in the process of evolution. Although the hologenome theory has become very popular among certain scientific circles, its principles are still being debated. In this paper, we argue, firstly, that only a very small number of symbiotic microorganisms are sufficiently integrated into multicellular organisms to act in concert with them as units of selection, thus rendering claims that holobionts are units of selection invalid. Secondly, even though holobionts are not units of selection, they can still constitute genuine units from an evolutionary perspective, provided we accept certain constraints: mainly, they should be considered units of co-operation. Thirdly, we propose a reconciliation of the role of symbiotic microorganisms with the theory of speciation through the use of a developed framework. Mainly, we will argue that, in order to understand the role of microorganisms in the speciation of multicellular organisms, it is not necessary to consider holobionts units of selection; it is sufficient to consider them units of co-operation.}, }
@article {pmid30065035, year = {2018}, author = {Armstrong, EJ and Roa, JN and Stillman, JH and Tresguerres, M}, title = {Symbiont photosynthesis in giant clams is promoted by V-type H+-ATPase from host cells.}, journal = {The Journal of experimental biology}, volume = {}, number = {}, pages = {}, doi = {10.1242/jeb.177220}, pmid = {30065035}, issn = {1477-9145}, abstract = {Giant clams (genus Tridacna) are the largest living bivalves and, like reef-building corals, host symbiotic dinoflagellate algae (Symbiodinium) that significantly contribute to their energy budget. In turn, Symbiodinium rely on the host to supply inorganic carbon (Ci) for photosynthesis. In corals, host &quot;proton pump&quot; vacuolar-type H+-ATPase (VHA) is part of a carbon concentrating mechanism (CCM) that promotes Symbiodinium photosynthesis. Here, we report that VHA in the small giant clam (Tridacna maxima) similarly promotes Symbiodinium photosynthesis. VHA was abundantly expressed in the apical membrane of epithelial cells of T. maxima's siphonal mantle tubule system which harbors Symbiodinium Furthermore, application of the highly specific pharmacological VHA inhibitors bafilomycin A1 and concanamycin A significantly reduced photosynthetic O2 production by ∼40%. Together with our observation that exposure to light increased holobiont aerobic metabolism ∼five-fold, and earlier estimates that translocated fixed carbon exceeds metabolic demand, we conclude that VHA activity in the siphonal mantle confers strong energetic benefits to the host clam through increased supply of Ci to algal symbionts and subsequent photosynthetic activity. The convergent role of VHA in promoting Symbiodinium photosynthesis in the giant clam siphonal mantle tubule system and coral symbiosome suggests VHA-driven CCM is a common exaptation in marine photosymbioses that deserves further investigation in other taxa.}, }
@article {pmid29941067, year = {2018}, author = {Marchesi, JR}, title = {Advancing microbiome research.}, journal = {Microbiology (Reading, England)}, volume = {164}, number = {8}, pages = {1005-1006}, doi = {10.1099/mic.0.000688}, pmid = {29941067}, issn = {1465-2080}, }
@article {pmid30057302, year = {2018}, author = {Berg, M and Koskella, B}, title = {Nutrient- and Dose-Dependent Microbiome-Mediated Protection against a Plant Pathogen.}, journal = {Current biology : CB}, volume = {}, number = {}, pages = {}, doi = {10.1016/j.cub.2018.05.085}, pmid = {30057302}, issn = {1879-0445}, abstract = {Plant-associated microbial communities can promote plant nutrient uptake, growth, and resistance to pathogens [1-3]. Host resistance to infection can increase directly through commensal-pathogen interactions or indirectly through modulation of host defenses [4-6], the mechanisms of which are best described for rhizosphere-associated bacteria. For example, Arabidopsis plants infected with the foliar pathogen, Pseudomonas syringae pathovar tomato (Pst), increase their root secretion of malate, which attracts Bacillus subtillis to the roots and leads to a stronger host response against Pst [7]. Although there are numerous examples of individual defensive symbionts (e.g., [8]), it is less clear whether this type of protection is an emergent property of whole microbial communities. In particular, relatively little is known about whether and how the presence of phyllosphere (above-ground) microbial communities can increase host resistance against pathogens. In this study, we examined the ability of augmented tomato phyllosphere microbiomes to confer resistance against the causal agent of bacterial speck, Pst. Across five independent experiments, the augmented phyllosphere microbiome was found to decrease pathogen colonization. Furthermore, the dose of commensal bacteria applied affected the degree of protection conferred, and although the effect is dependent on microbial composition, it is not clearly related to overall bacterial diversity. Finally, our results suggest that resources available to the phyllosphere microbial community may play an important role in protection, as the addition of fertilizer abolished the observed microbiome-mediated protection. Together, these results have clear relevance to microbiome-mediated protection within agricultural settings and the use of plant probiotics to increase disease resistance.}, }
@article {pmid30050510, year = {2018}, author = {Garcia, J and Kao-Kniffin, J}, title = {Microbial Group Dynamics in Plant Rhizospheres and Their Implications on Nutrient Cycling.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1516}, doi = {10.3389/fmicb.2018.01516}, pmid = {30050510}, issn = {1664-302X}, abstract = {Plant rhizospheres encompass a dynamic zone of interactions between microorganisms and their respective plant hosts. For decades, researchers have worked to understand how these complex interactions influence different aspects of plant growth, development, and evolution. Studies of plant-microbial interactions in the root zone have typically focused on the effect of single microbial species or strains on a plant host. These studies, however, provide only a snapshot of the complex interactions that occur in the rhizosphere, leaving researchers with a limited understanding of how the complex microbiome influences the biology of the plant host. To better understand how rhizosphere interactions influence plant growth and development, novel frameworks and research methodologies could be implemented. In this perspective, we propose applying concepts in evolutionary biology to microbiome experiments for improved understanding of group-to-group and community-level microbial interactions influencing soil nutrient cycling. We also put forth simple experimental designs utilizing -omics techniques that can reveal important changes in the rhizosphere impacting the plant host. A greater focus on the components of complexity of the microbiome and how these impact plant host biology could yield more insight into previously unexplored aspects of host-microbe biology relevant to crop production and protection.}, }
@article {pmid30046174, year = {2018}, author = {Klassen, JL}, title = {Defining microbiome function.}, journal = {Nature microbiology}, volume = {3}, number = {8}, pages = {864-869}, doi = {10.1038/s41564-018-0189-4}, pmid = {30046174}, issn = {2058-5276}, abstract = {Why does a microorganism associate with a host? What function does it perform? Such questions are difficult to unequivocally address and remain hotly debated. This is partially because scientists often use different philosophical definitions of 'function' ambiguously and interchangeably, as exemplified by the controversy surrounding the Encyclopedia of DNA Elements (ENCODE) project. Here, I argue that research studying host-associated microbial communities and their genomes (that is, microbiomes) faces similar pitfalls and that unclear or misapplied conceptions of function underpin many controversies in this field. In particular, experiments that support phenomenological models of function can inappropriately be used to support functional models that instead require specific measurements of evolutionary selection. Microbiome research also requires uniquely clear definitions of 'who the function is for', in contrast to most single-organism systems where this is implicit. I illustrate how obscuring either of these issues can lead to substantial confusion and misinterpretation of microbiome function, using the varied conceptions of the holobiont as a current and cogent example. Using clear functional definitions and appropriate types of evidence are essential to effectively communicate microbiome research and foster host health.}, }
@article {pmid30038485, year = {2018}, author = {Karimi, K and Wuitchik, DM and Oldach, MJ and Vize, PD}, title = {Distinguishing Species Using GC Contents in Mixed DNA or RNA Sequences.}, journal = {Evolutionary bioinformatics online}, volume = {14}, number = {}, pages = {1176934318788866}, doi = {10.1177/1176934318788866}, pmid = {30038485}, issn = {1176-9343}, abstract = {With the advent of whole transcriptome and genome analysis methods, classifying samples containing multiple origins has become a significant task. Nucleotide sequences can be allocated to a genome or transcriptome by aligning sequences to multiple target sequence sets, but this approach requires extensive computational resources and also depends on target sequence sets lacking contaminants, which is often not the case. Here, we demonstrate that raw sequences can be rapidly sorted into groups, in practice corresponding to genera, by exploiting differences in nucleotide GC content. To do so, we introduce GCSpeciesSorter, which uses classification, specifically Support Vector Machines (SVM) and the C4.5 decision tree generator, to differentiate sequences. It also implements a secondary BLAST feature to identify known outliers. In the test case presented, a hermatypic coral holobiont, the cnidarian host includes various endosymbionts. The best characterized and most common of these symbionts are zooxanthellae of the genus Symbiodinium. GCSpeciesSorter separates cnidarian from Symbiodinium sequences with a high degree of accuracy. We show that if the GC contents of the species differ enough, this method can be used to accurately distinguish the sequences of different species when using high-throughput sequencing technologies.}, }
@article {pmid30022157, year = {2018}, author = {Li, Y and Liles, MR and Halanych, KM}, title = {Endosymbiont genomes yield clues of tubeworm success.}, journal = {The ISME journal}, volume = {}, number = {}, pages = {}, doi = {10.1038/s41396-018-0220-z}, pmid = {30022157}, issn = {1751-7370}, support = {IOS-0843473//National Science Foundation (NSF)/ ; DEB-1036537//National Science Foundation (NSF)/ ; IOS-0843473//National Science Foundation (NSF)/ ; }, abstract = {Forty years after discovery of chemosynthetic symbiosis in the tubeworm Riftia pachyptila, how organisms maintain their unique host-symbiont associations at the cellular level is still largely unknown. Previous studies primarily focus on symbionts associated with host lineages living in hydrothermal vents. To understand physiological adaptations and evolution in these holobiont systems in markedly different habitats, we characterized four novel siboglinid-symbiont genomes spanning deep-sea seep and sedimented environments. Our comparative analyses suggest that all sampled siboglinid chemoautotrophic symbionts, except for frenulate symbionts, can use both rTCA and Calvin cycle for carbon fixation. We hypothesize that over evolutionary time siboglinids have been able to utilize different bacterial lineages allowing greater metabolic flexibility of carbon fixation (e.g., rTCA) enabling tubeworms to thrive in more reducing habitats, such as vents and seeps. Moreover, we show that sulfur metabolism and molecular mechanisms related to initial infection are remarkably conserved across chemoautotrophic symbionts in different habitats. Unexpectedly, we find that the ability to use hydrogen, as an additional energy source, is potentially more widespread than previously recognized. Our comparative genomic results help elucidate potential mechanisms used to allow chemosynthetically dependent holobionts adapt to, and evolve in, different environments.}, }
@article {pmid30003599, year = {2018}, author = {Lorimer, J}, title = {Hookworms Make Us Human: The Microbiome, Eco-immunology, and a Probiotic Turn in Western Health Care.}, journal = {Medical anthropology quarterly}, volume = {}, number = {}, pages = {}, doi = {10.1111/maq.12466}, pmid = {30003599}, issn = {0745-5194}, abstract = {Historians of science have identified an ecological turn underway in immunology, driven by the mapping of the human microbiome and wider environmentalist anxieties. A figure is emerging of the human as a holobiont, composed of microbes and threatened by both microbial excess and microbial absence. Antimicrobial approaches to germ warfare are being supplemented by probiotic approaches to restoring microbial life. This article examines the political ecology of this probiotic turn in Western health care. It focuses on Necator americanus-a species of human hookworm-and its relations with immunologists. The analysis moves from a history of human disentanglement from hookworm, to contemporary anxieties about their absence. It examines the reintroduction of worms for helminthic therapy and explores emerging trajectories for probiotic health care involving the synthesis, modification, and/or restoration of worms and their salutary ecologies. The conclusion differentiates these trajectories and identifies an emerging model of &quot;post-paleo&quot; microbiopolitics. This article is protected by copyright. All rights reserved.}, }
@article {pmid29989180, year = {2018}, author = {Klimovich, AV and Bosch, TCG}, title = {Rethinking the Role of the Nervous System: Lessons From the Hydra Holobiont.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {}, number = {}, pages = {e1800060}, doi = {10.1002/bies.201800060}, pmid = {29989180}, issn = {1521-1878}, abstract = {Here we evaluate our current understanding of the function of the nervous system in Hydra, a non-bilaterian animal which is among the first metazoans that contain neurons. We highlight growing evidence that the nervous system, with its rich repertoire of neuropeptides, is involved in controlling resident beneficial microbes. We also review observations that indicate that microbes affect the animal's behavior by directly interfering with neuronal receptors. These findings provide new insight into the original role of the nervous system, and suggest that it emerged to orchestrate multiple functions including host-microbiome interactions. The excitement of future research in the Hydra model now relies on uncovering the common rules and principles that govern the interaction between neurons and microbes and the extent to which such laws might apply to other and more complex organisms.}, }
@article {pmid29978601, year = {2018}, author = {Lian, J and Wijffels, RH and Smidt, H and Sipkema, D}, title = {The effect of the algal microbiome on industrial production of microalgae.}, journal = {Microbial biotechnology}, volume = {}, number = {}, pages = {}, doi = {10.1111/1751-7915.13296}, pmid = {29978601}, issn = {1751-7915}, abstract = {Microbes are ubiquitously distributed, and they are also present in algae production systems. The algal microbiome is a pivotal part of the alga holobiont and has a key role in modulating algal populations in nature. However, there is a lack of knowledge on the role of bacteria in artificial systems ranging from laboratory flasks to industrial ponds. Coexisting microorganisms, and predominantly bacteria, are often regarded as contaminants in algal research, but recent studies manifested that many algal symbionts not only promote algal growth but also offer advantages in downstream processing. Because of the high expectations for microalgae in a bio-based economy, better understanding of benefits and risks of algal-microbial associations is important for the algae industry. Reducing production cost may be through applying specific bacteria to enhance algae growth at large scale as well as through preventing the growth of a broad spectrum of algal pathogens. In this review, we highlight the latest studies of algae-microbial interactions and their underlying mechanisms, discuss advantages of large-scale algal-bacterial cocultivation and extend such knowledge to a broad range of biotechnological applications.}, }
@article {pmid29948922, year = {2018}, author = {Kutschera, U}, title = {Systems biology of eukaryotic superorganisms and the holobiont concept.}, journal = {Theory in biosciences = Theorie in den Biowissenschaften}, volume = {}, number = {}, pages = {}, doi = {10.1007/s12064-018-0265-6}, pmid = {29948922}, issn = {1611-7530}, support = {Stanford U. Kut. 2013/14//Alexander von Humboldt-Stiftung/ ; }, abstract = {The founders of modern biology (Jean Lamarck, Charles Darwin, August Weismann etc.) were organismic life scientists who attempted to understand the morphology and evolution of living beings as a whole (i.e., the phenotype). However, with the emergence of the study of animal and plant physiology in the nineteenth century, this &quot;holistic view&quot; of the living world changed and was ultimately replaced by a reductionistic perspective. Here, I summarize the history of systems biology, i.e., the modern approach to understand living beings as integrative organisms, from genotype to phenotype. It is documented that the physiologists Claude Bernard and Julius Sachs, who studied humans and plants, respectively, were early pioneers of this discipline, which was formally founded 50 years ago. In 1968, two influential monographs, authored by Ludwig von Bertalanffy and Mihajlo D. Mesarović, were published, wherein a &quot;systems theory of biology&quot; was outlined. Definitions of systems biology are presented with reference to metabolic or cell signaling networks, analyzed via genomics, proteomics, and other methods, combined with computer simulations/mathematical modeling. Then, key insights of this discipline with respect to epiphytic microbes (Methylobacterium sp.) and simple bacteria (Mycoplasma sp.) are described. The principles of homeostasis, molecular systems energetics, gnotobiology, and holobionts (i.e., complexities of host-microbiota interactions) are outlined, and the significance of systems biology for evolutionary theories is addressed. Based on the microbe-Homo sapiens-symbiosis, it is concluded that human biology and health should be interpreted in light of a view of the biomedical sciences that is based on the holobiont concept.}, }
@article {pmid29946243, year = {2018}, author = {Münger, E and Montiel-Castro, AJ and Langhans, W and Pacheco-López, G}, title = {Reciprocal Interactions Between Gut Microbiota and Host Social Behavior.}, journal = {Frontiers in integrative neuroscience}, volume = {12}, number = {}, pages = {21}, doi = {10.3389/fnint.2018.00021}, pmid = {29946243}, issn = {1662-5145}, abstract = {Animals harbor an extensive, dynamic microbial ecosystem in their gut. Gut microbiota (GM) supposedly modulate various host functions including fecundity, metabolism, immunity, cognition and behavior. Starting by analyzing the concept of the holobiont as a unit of selection, we highlight recent findings suggesting an intimate link between GM and animal social behavior. We consider two reciprocal emerging themes: (i) that GM influence host social behavior; and (ii) that social behavior and social structure shape the composition of the GM across individuals. We propose that, throughout a long history of coevolution, GM may have become involved in the modulation of their host's sociality to foster their own transmission, while in turn social organization may have fine-tuned the transmission of beneficial endosymbionts and prevented pathogen infection. We suggest that investigating these reciprocal interactions can advance our understanding of sociality, from healthy and impaired social cognition to the evolution of specific social behaviors and societal structure.}, }
@article {pmid29943448, year = {2018}, author = {Marchesi, JR}, title = {Advancing microbiome research.}, journal = {Immunology}, volume = {}, number = {}, pages = {}, doi = {10.1111/imm.12973}, pmid = {29943448}, issn = {1365-2567}, }
@article {pmid29922264, year = {2018}, author = {Yurgel, SN and Douglas, GM and Dusault, A and Percival, D and Langille, MGI}, title = {Dissecting Community Structure in Wild Blueberry Root and Soil Microbiome.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {1187}, doi = {10.3389/fmicb.2018.01187}, pmid = {29922264}, issn = {1664-302X}, abstract = {A complex network of functions and symbiotic interactions between a eukaryotic host and its microbiome is a the foundation of the ecological unit holobiont. However, little is known about how the non-fungal eukaryotic microorganisms fit in this complex network of host-microbiome interactions. In this study, we employed a unique wild blueberry ecosystem to evaluate plant-associated microbiota, encompassing both eukaryotic and bacterial communities. We found that, while soil microbiome serves as a foundation for root microbiome, plant-influenced species sorting had stronger effect on eukaryotes than on bacteria. Our study identified several fungal and protist taxa, which are correlated with decreased fruit production in wild blueberry agricultural ecosystems. The specific effect of species sorting in root microbiome resulted in an increase in relative abundance of fungi adapted to plant-associated life-style, while the relative abundance of non-fungal eukaryotes was decreased along the soil-endosphere continuum in the root, probably because of low adaptation of these microorganisms to host-plant defense responses. Analysis of community correlation networks indicated that bacterial and eukaryotic interactions became more complex along the soil-endosphere continuum and, in addition to extensive mutualistic interactions, co-exclusion also played an important role in shaping wild blueberry associated microbiome. Our study identified several potential hub taxa with important roles in soil fertility and/or plant-microbe interaction, suggesting the key role of these taxa in the interconnection between soils and plant health and overall microbial community structure. This study also provides a comprehensive view of the role of non-fungal eukaryotes in soil ecosystem.}, }
@article {pmid29917104, year = {2018}, author = {Celis, JS and Wibberg, D and Ramírez-Portilla, C and Rupp, O and Sczyrba, A and Winkler, A and Kalinowski, J and Wilke, T}, title = {Binning enables efficient host genome reconstruction in cnidarian holobionts.}, journal = {GigaScience}, volume = {7}, number = {7}, pages = {}, doi = {10.1093/gigascience/giy075}, pmid = {29917104}, issn = {2047-217X}, abstract = {Background: Many cnidarians, including stony corals, engage in complex symbiotic associations, comprising the eukaryotic host, photosynthetic algae, and highly diverse microbial communities-together referred to as holobiont. This taxonomic complexity makes sequencing and assembling coral host genomes extremely challenging. Therefore, previous cnidarian genomic projects were based on symbiont-free tissue samples. However, this approach may not be applicable to the majority of cnidarian species for ecological reasons. We therefore evaluated the performance of an alternative method based on sequence binning for reconstructing the genome of the stony coral Porites rus from a hologenomic sample and compared it to traditional approaches.<br><br>Results: Our results demonstrate that binning performs well for hologenomic data, producing sufficient reads for assembling the draft genome of P. rus. An assembly evaluation based on operational criteria showed results that were comparable to symbiont-free approaches in terms of completeness and usefulness, despite a high degree of fragmentation in our assembly. In addition, we found that binning provides sufficient data for exploratory k-mer estimation of genomic features, such as genome size and heterozygosity.<br><br>Conclusions: Binning constitutes a powerful approach for disentangling taxonomically complex coral hologenomes. Considering the recent decline of coral reefs on the one hand and previous limitations to coral genome sequencing on the other hand, binning may facilitate rapid and reliable genome assembly. This study also provides an important milestone in advancing binning from the metagenomic to the hologenomic and from the prokaryotic to the eukaryotic level.}, }
@article {pmid29900626, year = {2018}, author = {van Oppen, MJH and Bongaerts, P and Frade, P and Peplow, LM and Boyd, SE and Nim, HT and Bay, LK}, title = {Adaptation to reef habitats through selection on the coral animal and its associated microbiome.}, journal = {Molecular ecology}, volume = {27}, number = {14}, pages = {2956-2971}, doi = {10.1111/mec.14763}, pmid = {29900626}, issn = {1365-294X}, abstract = {Spatially adjacent habitats on coral reefs can represent highly distinct environments, often harbouring different coral communities. Yet, certain coral species thrive across divergent environments. It is unknown whether the forces of selection are sufficiently strong to overcome the counteracting effects of the typically high gene flow over short distances, and for local adaptation to occur. We screened the coral genome (using restriction site-associated sequencing) and characterized both the dinoflagellate photosymbiont- and tissue-associated prokaryote microbiomes (using metabarcoding) of a reef flat and slope population of the reef-building coral, Pocillopora damicornis, at two locations on Heron Island in the southern Great Barrier Reef. Reef flat and slope populations were separated by <100 m horizontally and ~5 m vertically, and the two study locations were separated by ~1 km. For the coral host, genetic divergence between habitats was much greater than between locations, suggesting limited gene flow between the flat and slope populations. Consistent with environmental selection, outlier loci primarily belonged to the conserved, minimal cellular stress response, likely reflecting adaptation to the different temperature and irradiance regimes on the reef flat and slope. The prokaryote community differed across both habitat and, to a lesser extent, location, whereas the dinoflagellate photosymbionts differed by habitat but not location. The observed intraspecific diversity associated with divergent habitats supports that environmental adaptation involves multiple members of the coral holobiont. Adaptive alleles or microbial associations present in coral populations from the environmentally variable reef flat may provide a source of adaptive variation for assisted evolution approaches, through assisted gene flow, artificial cross-breeding or probiotic inoculations, with the aim to increase climate resilience in the slope populations.}, }
@article {pmid29900606, year = {2018}, author = {Vančurová, L and Muggia, L and Peksa, O and Řídká, T and Škaloud, P}, title = {The complexity of symbiotic interactions influences the ecological amplitude of the host: A case study in Stereocaulon (lichenized Ascomycota).}, journal = {Molecular ecology}, volume = {27}, number = {14}, pages = {3016-3033}, doi = {10.1111/mec.14764}, pmid = {29900606}, issn = {1365-294X}, abstract = {Symbiosis plays a fundamental role in nature. Lichens are among the best known, globally distributed symbiotic systems whose ecology is shaped by the requirements of all symbionts forming the holobiont. The widespread lichen-forming fungal genus Stereocaulon provides a suitable model to study the ecology of microscopic green algal symbionts (i.e., phycobionts) within the lichen symbiosis. We analysed 282 Stereocaulon specimens, collected in diverse habitats worldwide, using the algal ITS rDNA and actin gene sequences and fungal ITS rDNA sequences. Phylogenetic analyses revealed a great diversity among the predominant phycobionts. The algal genus Asterochloris (Trebouxiophyceae) was recovered in most sampled thalli, but two additional genera, Vulcanochloris and Chloroidium, were also found. We used variation-partitioning analyses to investigate the effects of climatic conditions, substrate/habitat characteristic, spatial distribution and mycobionts on phycobiont distribution. Based on an analogy, we examined the effects of climate, substrate/habitat, spatial distribution and phycobionts on mycobiont distribution. According to our analyses, the distribution of phycobionts is primarily driven by mycobionts and vice versa. Specificity and selectivity of both partners, as well as their ecological requirements and the width of their niches, vary significantly among the species-level lineages. We demonstrated that species-level lineages, which accept more symbiotic partners, have wider climatic niches, overlapping with the niches of their partners. Furthermore, the survival of lichens on substrates with high concentrations of heavy metals appears to be supported by their association with toxicity-tolerant phycobionts. In general, low specificity towards phycobionts allows the host to associate with ecologically diversified algae, thereby broadening its ecological amplitude.}, }
@article {pmid29899267, year = {2018}, author = {R L Morlighem, JÉ and Huang, C and Liao, Q and Braga Gomes, P and Daniel Pérez, C and de Brandão Prieto-da-Silva, ÁR and Ming-Yuen Lee, S and Rádis-Baptista, G}, title = {The Holo-Transcriptome of the Zoantharian Protopalythoa variabilis (Cnidaria: Anthozoa): A Plentiful Source of Enzymes for Potential Application in Green Chemistry, Industrial and Pharmaceutical Biotechnology.}, journal = {Marine drugs}, volume = {16}, number = {6}, pages = {}, doi = {10.3390/md16060207}, pmid = {29899267}, issn = {1660-3397}, abstract = {Marine invertebrates, such as sponges, tunicates and cnidarians (zoantharians and scleractinian corals), form functional assemblages, known as holobionts, with numerous microbes. This type of species-specific symbiotic association can be a repository of myriad valuable low molecular weight organic compounds, bioactive peptides and enzymes. The zoantharian Protopalythoa variabilis (Cnidaria: Anthozoa) is one such example of a marine holobiont that inhabits the coastal reefs of the tropical Atlantic coast and is an interesting source of secondary metabolites and biologically active polypeptides. In the present study, we analyzed the entire holo-transcriptome of P. variabilis, looking for enzyme precursors expressed in the zoantharian-microbiota assemblage that are potentially useful as industrial biocatalysts and biopharmaceuticals. In addition to hundreds of predicted enzymes that fit into the classes of hydrolases, oxidoreductases and transferases that were found, novel enzyme precursors with multiple activities in single structures and enzymes with incomplete Enzyme Commission numbers were revealed. Our results indicated the predictive expression of thirteen multifunctional enzymes and 694 enzyme sequences with partially characterized activities, distributed in 23 sub-subclasses. These predicted enzyme structures and activities can prospectively be harnessed for applications in diverse areas of industrial and pharmaceutical biotechnology.}, }
@article {pmid29888140, year = {2018}, author = {Nguyen, MTHD and Thomas, T}, title = {Diversity, host-specificity and stability of sponge-associated fungal communities of co-occurring sponges.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e4965}, doi = {10.7717/peerj.4965}, pmid = {29888140}, issn = {2167-8359}, abstract = {Fungi play a critical role in a range of ecosystems; however, their interactions and functions in marine hosts, and particular sponges, is poorly understood. Here we assess the fungal community composition of three co-occurring sponges (Cymbastela concentrica, Scopalina sp., Tedania anhelans) and the surrounding seawater over two time points to help elucidate host-specificity, stability and potential core members, which may shed light into the ecological function of fungi in sponges. The results showed that ITS-amplicon-based community profiling likely provides a more realistic assessment of fungal diversity in sponges than cultivation-dependent approaches. The sponges studied here were found to contain phylogenetically diverse fungi (eight fungal classes were observed), including members of the family Togniniaceae and the genus Acrostalagmus, that have so far not been reported to be cultured from sponges. Fungal communities within any given sponge species were found to be highly variable compared to bacterial communities, and influenced in structure by the community of the surrounding seawater, especially considering temporal variation. Nevertheless, the sponge species studied here contained a few &quot;variable/core&quot; fungi that appeared in multiple biological replicates and were enriched in their relative abundance compared to seawater communities. These fungi were the same or highly similar to fungal species detected in sponges around the world, which suggests a prevalence of horizontal transmission where selectivity and enrichment of some fungi occur for those that can survive and/or exploit the sponge environment. Our current sparse knowledge about sponge-associated fungi thus indicate that fungal communities may perhaps not play as an important ecological role in the sponge holobiont compared to bacterial or archaeal symbionts.}, }
@article {pmid29886997, year = {2018}, author = {Hall, ER and Muller, EM and Goulet, T and Bellworthy, J and Ritchie, KB and Fine, M}, title = {Eutrophication may compromise the resilience of the Red Sea coral Stylophora pistillata to global change.}, journal = {Marine pollution bulletin}, volume = {131}, number = {Pt A}, pages = {701-711}, doi = {10.1016/j.marpolbul.2018.04.067}, pmid = {29886997}, issn = {1879-3363}, abstract = {Environmental stressors are adversely affecting coral reef ecosystems. There is ample evidence that scleractinian coral growth and physiology may be compromised by reduced pH, and elevated temperature, and that this is exacerbated by local environmental stressors. The Gulf of Aqaba is considered a coral reef refuge from acidification and warming but coastal development and nutrient effluent may pose a local threat. This study examined the effects of select forecasted environmental changes (acidification, warming, and increased nutrients) individually and in combination on the coral holobiont Stylophora pistillata from the Gulf of Aqaba to understand how corals in a potential global climate change refugia may fare in the face of local eutrophication. The results indicate interactions between all stressors, with elevated nutrient concentrations having the broadest individual and additive impacts upon the performance of S. pistillata. These findings highlight the importance of maintaining oligotrophic conditions to secure these reefs as potential refugia.}, }
@article {pmid29885666, year = {2018}, author = {Meng, A and Marchet, C and Corre, E and Peterlongo, P and Alberti, A and Da Silva, C and Wincker, P and Pelletier, E and Probert, I and Decelle, J and Le Crom, S and Not, F and Bittner, L}, title = {A de novo approach to disentangle partner identity and function in holobiont systems.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {105}, doi = {10.1186/s40168-018-0481-9}, pmid = {29885666}, issn = {2049-2618}, support = {ANR-15-CE02-0011//Agence Nationale de la Recherche (FR)/ ; }, abstract = {BACKGROUND: Study of meta-transcriptomic datasets involving non-model organisms represents bioinformatic challenges. The production of chimeric sequences and our inability to distinguish the taxonomic origins of the sequences produced are inherent and recurrent difficulties in de novo assembly analyses. As the study of holobiont meta-transcriptomes is affected by challenges invoked above, we propose an innovative bioinformatic approach to tackle such difficulties and tested it on marine models as a proof of concept.<br><br>RESULTS: We considered three holobiont models, of which two transcriptomes were previously published and a yet unpublished transcriptome, to analyze and sort their raw reads using Short Read Connector, a k-mer based similarity method. Before assembly, we thus defined four distinct categories for each holobiont meta-transcriptome: host reads, symbiont reads, shared reads, and unassigned reads. Afterwards, we observed that independent de novo assemblies for each category led to a diminution of the number of chimeras compared to classical assembly methods. Moreover, the separation of each partner's transcriptome offered the independent and comparative exploration of their functional diversity in the holobiont. Finally, our strategy allowed to propose new functional annotations for two well-studied holobionts (a Cnidaria-Dinophyta, a Porifera-Bacteria) and a first meta-transcriptome from a planktonic Radiolaria-Dinophyta system forming widespread symbiotic association for which our knowledge is considerably limited.<br><br>CONCLUSIONS: In contrast to classical assembly approaches, our bioinformatic strategy generates less de novo assembled chimera and allows biologists to study separately host and symbiont data from a holobiont mixture. The pre-assembly separation of reads using an efficient tool as Short Read Connector is an effective way to tackle meta-transcriptomic challenges and offers bright perpectives to study holobiont systems composed of either well-studied or poorly characterized symbiotic lineages and ultimately expand our knowledge about these associations.}, }
@article {pmid29795808, year = {2018}, author = {Rädecker, N and Raina, JB and Pernice, M and Perna, G and Guagliardo, P and Kilburn, MR and Aranda, M and Voolstra, CR}, title = {Corrigendum: Using Aiptasia as a Model to Study Metabolic Interactions in Cnidarian-Symbiodinium Symbioses.}, journal = {Frontiers in physiology}, volume = {9}, number = {}, pages = {449}, doi = {10.3389/fphys.2018.00449}, pmid = {29795808}, issn = {1664-042X}, abstract = {[This corrects the article on p. 214 in vol. 9, PMID: 29615919.].}, }
@article {pmid29766224, year = {2018}, author = {García-Bonilla, E and Brandão, PFB and Pérez, T and Junca, H}, title = {Stable and Enriched Cenarchaeum symbiosum and Uncultured Betaproteobacteria HF1 in the Microbiome of the Mediterranean Sponge Haliclona fulva (Demospongiae: Haplosclerida).}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1201-5}, pmid = {29766224}, issn = {1432-184X}, support = {Doctoral Grant (Convocatoria 528-2011)//Colciencias-Colfuturo/ ; Projects (2012-2014 and 2015-2017//EcosNord-Colciencias/ ; }, abstract = {Sponges harbor characteristic microbiomes derived from symbiotic relationships shaping their lifestyle and survival. Haliclona fulva is encrusting marine sponge species dwelling in coralligenous accretions or semidark caves of the Mediterranean Sea and the near Atlantic Ocean. In this work, we characterized the abundance and core microbial community composition found in specimens of H. fulva by means of electron microscopy and 16S amplicon Illumina sequencing. We provide evidence of its low microbial abundance (LMA) nature. We found that the H. fulva core microbiome is dominated by sequences belonging to the orders Nitrosomonadales and Cenarchaeales. Seventy percent of the reads assigned to these phylotypes grouped in a very small number of high-frequency operational taxonomic units, representing niche-specific species Cenarchaeum symbiosum and uncultured Betaproteobacteria HF1, a new eubacterial ribotype variant found in H. fulva. The microbial composition of H. fulva is quite distinct from those reported in sponge species of the same Haliclona genus. We also detected evidence of an excretion/capturing loop between these abundant microorganisms and planktonic microbes by analyzing shifts in seawater planktonic microbial content exposed to healthy sponge specimens maintained in aquaria. Our results suggest that horizontal transmission is very likely the main mechanism for symbionts' acquisition by H. fulva. So far, this is the first shallow water sponge species harboring such a specific and predominant assemblage composed of these eubacterial and archaeal ribotypes. Our data suggests that this symbiotic relationship is very stable over time, indicating that the identified core microbial symbionts may play key roles in the holobiont functioning.}, }
@article {pmid29765310, year = {2018}, author = {Houdek, P}, title = {Economic Holobiont: Influence of Parasites, Microbiota and Chemosignals on Economic Behavior.}, journal = {Frontiers in behavioral neuroscience}, volume = {12}, number = {}, pages = {77}, doi = {10.3389/fnbeh.2018.00077}, pmid = {29765310}, issn = {1662-5153}, abstract = {The article is a perspective on utilization of microorganisms and chemosignals in studying human economic behavior. Research in biological roots of economic development has already confirmed that parasitic pressure influenced the creation and development of cultural norms and institutions. However, other effects of microorganisms on human groups and individual decision-making and behavior are heavily understudied. The perspective discusses how parasitic infections, sexually transmitted organisms and microbiota (i.e., &quot;human holobiont&quot;) could causally influence risk-seeking behavior, impulsivity, social dominance, empathy, political views and gender differences. As a case study, the parasite Toxoplasma gondii and its influence on economic preferences, personal characteristics and human appearance are examined. I also briefly review how chemosignals influence decision-making, particularly in the social preferences domain. I mention some predictions that arise from the paradigm of economic holobiont for the economic science. The conclusion summarizes limitations of the discussed findings and the stated speculations.}, }
@article {pmid29761370, year = {2018}, author = {Bourrat, P and Griffiths, PE}, title = {Multispecies individuals.}, journal = {History and philosophy of the life sciences}, volume = {40}, number = {2}, pages = {33}, doi = {10.1007/s40656-018-0194-1}, pmid = {29761370}, issn = {0391-9714}, support = {DP0878650//Australian Research Council (AU)/ ; }, abstract = {We assess the arguments for recognising functionally integrated multispecies consortia as genuine biological individuals, including cases of so-called 'holobionts'. We provide two examples in which the same core biochemical processes that sustain life are distributed across a consortium of individuals of different species. Although the same chemistry features in both examples, proponents of the holobiont as unit of evolution would recognize one of the two cases as a multispecies individual whilst they would consider the other as a compelling case of ecological dependence between separate individuals. Some widely used arguments in support of the 'holobiont' concept apply equally to both cases, suggesting that those arguments have misidentified what is at stake when seeking to identify a new level of biological individuality. One important aspect of biological individuality is evolutionary individuality. In line with other work on the evolution of individuality, we show that our cases can be distinguished by focusing on the fitness alignment between the partners of the consortia. We conclude that much of the evidence currently presented for the ubiquity and importance of multi-species individuals is simply not to the point, at least unless the issue of biological individuality is firmly divorced from the question of evolutionary individuality.}, }
@article {pmid29742123, year = {2018}, author = {León-Palmero, E and Joglar, V and Álvarez, PA and Martín-Platero, A and Llamas, I and Reche, I}, title = {Diversity and antimicrobial potential in sea anemone and holothurian microbiomes.}, journal = {PloS one}, volume = {13}, number = {5}, pages = {e0196178}, doi = {10.1371/journal.pone.0196178}, pmid = {29742123}, issn = {1932-6203}, abstract = {Marine invertebrates, as holobionts, contain symbiotic bacteria that coevolve and develop antimicrobial substances. These symbiotic bacteria are an underexplored source of new bioactive molecules to face the emerging antibiotic resistance in pathogens. Here, we explored the antimicrobial activity of bacteria retrieved from the microbiota of two sea anemones (Anemonia sulcata, Actinia equina) and two holothurians (Holothuria tubulosa, Holothuria forskali). We tested the antimicrobial activity of the isolated bacteria against pathogens with interest for human health, agriculture and aquaculture. We isolated 27 strains with antibacterial activity and 12 of these isolates also showed antifungal activity. We taxonomically identified these strains being Bacillus and Vibrio species the most representative producers of antimicrobial substances. Microbiome species composition of the two sea anemones was similar between them but differed substantially of seawater bacteria. In contrast, microbiome species composition of the two holothurian species was different between them and in comparison with the bacteria in holothurian feces and seawater. In all the holobiont microbiomes Bacteroidetes was the predominant phylum. For each microbiome, we determined diversity and the rank-abundance dominance using five fitted models (null, pre-emption, log-Normal, Zipf and Zipf-Mandelbrot). The models with less evenness (i.e. Zipf and Zipf-Mandelblot) showed the best fits in all the microbiomes. Finally, we tracked (using the V4 hypervariable region of 16S rRNA gene) the relative abundance of these 27 isolates with antibacterial activity in the total pool of sequences obtained for the microbiome of each holobiont. Coincidences, although with extremely low frequencies, were detected only in the microbiome of H. forskali. This fact suggests that these isolated bacteria belong to the long tail of rare symbiotic bacteria. Therefore, more and more sophisticated culture techniques are necessary to explore this apparently vast pool of rare symbiontic bacteria and to determine their biotechnological potentiality.}, }
@article {pmid29740401, year = {2018}, author = {Domin, H and Zurita-Gutiérrez, YH and Scotti, M and Buttlar, J and Hentschel Humeida, U and Fraune, S}, title = {Predicted Bacterial Interactions Affect in Vivo Microbial Colonization Dynamics in Nematostella.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {728}, doi = {10.3389/fmicb.2018.00728}, pmid = {29740401}, issn = {1664-302X}, abstract = {The maintenance and resilience of host-associated microbiota during development is a fundamental process influencing the fitness of many organisms. Several host properties were identified as influencing factors on bacterial colonization, including the innate immune system, mucus composition, and diet. In contrast, the importance of bacteria-bacteria interactions on host colonization is less understood. Here, we use bacterial abundance data of the marine model organism Nematostella vectensis to reconstruct potential bacteria-bacteria interactions through co-occurrence networks. The analysis indicates that bacteria-bacteria interactions are dynamic during host colonization and change according to the host's developmental stage. To assess the predictive power of inferred interactions, we tested bacterial isolates with predicted cooperative or competitive behavior for their ability to influence bacterial recolonization dynamics. Within 3 days of recolonization, all tested bacterial isolates affected bacterial community structure, while only competitive bacteria increased bacterial diversity. Only 1 week after recolonization, almost no differences in bacterial community structure could be observed between control and treatments. These results show that predicted competitive bacteria can influence community structure for a short period of time, verifying the in silico predictions. However, within 1 week, the effects of the bacterial isolates are neutralized, indicating a high degree of resilience of the bacterial community.}, }
@article {pmid29739445, year = {2018}, author = {Sorek, M and Schnytzer, Y and Ben-Asher, HW and Caspi, VC and Chen, CS and Miller, DJ and Levy, O}, title = {Setting the pace: host rhythmic behaviour and gene expression patterns in the facultatively symbiotic cnidarian Aiptasia are determined largely by Symbiodinium.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {83}, doi = {10.1186/s40168-018-0465-9}, pmid = {29739445}, issn = {2049-2618}, support = {1294//Taiwan-Israel cooperative program/ ; }, abstract = {BACKGROUND: All organisms employ biological clocks to anticipate physical changes in the environment; however, the integration of biological clocks in symbiotic systems has received limited attention. In corals, the interpretation of rhythmic behaviours is complicated by the daily oscillations in tissue oxygen tension resulting from the photosynthetic and respiratory activities of the associated algal endosymbiont Symbiodinium. In order to better understand the integration of biological clocks in cnidarian hosts of Symbiodinium, daily rhythms of behaviour and gene expression were studied in symbiotic and aposymbiotic morphs of the sea-anemone Aiptasia diaphana.<br><br>RESULTS: The results showed that whereas circatidal (approx. 12-h) cycles of activity and gene expression predominated in aposymbiotic morphs, circadian (approx. 24-h) patterns were the more common in symbiotic morphs, where the expression of a significant number of genes shifted from a 12- to 24-h rhythm. The behavioural experiments on symbiotic A. diaphana displayed diel (24-h) rhythmicity in body and tentacle contraction under the light/dark cycles, whereas aposymbiotic morphs showed approximately 12-h (circatidal) rhythmicity. Reinfection experiments represent an important step in understanding the hierarchy of endogenous clocks in symbiotic associations, where the aposymbiotic Aiptasia morphs returned to a 24-h behavioural rhythm after repopulation with algae.<br><br>CONCLUSION: Whilst some modification of host metabolism is to be expected, the extent to which the presence of the algae modified host endogenous behavioural and transcriptional rhythms implies that it is the symbionts that influence the pace. Our results clearly demonstrate the importance of the endosymbiotic algae in determining the timing and the duration of the extension and contraction of the body and tentacles and temporal gene expression.}, }
@article {pmid29738088, year = {2018}, author = {Faure, D and Simon, JC and Heulin, T}, title = {Holobiont: a conceptual framework to explore the eco-evolutionary and functional implications of host-microbiota interactions in all ecosystems.}, journal = {The New phytologist}, volume = {218}, number = {4}, pages = {1321-1324}, doi = {10.1111/nph.15199}, pmid = {29738088}, issn = {1469-8137}, }
@article {pmid29714033, year = {2018}, author = {Nobori, T and Mine, A and Tsuda, K}, title = {Molecular networks in plant-pathogen holobiont.}, journal = {FEBS letters}, volume = {592}, number = {12}, pages = {1937-1953}, doi = {10.1002/1873-3468.13071}, pmid = {29714033}, issn = {1873-3468}, abstract = {Plant immune receptors enable detection of a multitude of microbes including pathogens. The recognition of microbes activates various plant signaling pathways, such as those mediated by phytohormones. Over the course of coevolution with microbes, plants have expanded their repertoire of immune receptors and signaling components, resulting in highly interconnected plant immune networks. These immune networks enable plants to appropriately respond to different types of microbes and to coordinate immune responses with developmental programs and environmental stress responses. However, the interconnectivity in plant immune networks is exploited by microbial pathogens to promote pathogen fitness in plants. Analogous to plant immune networks, virulence-related pathways in bacterial pathogens are also interconnected. Accumulating evidence implies that some plant-derived compounds target bacterial virulence networks. Thus, the plant immune and bacterial virulence networks intimately interact with each other. Here, we highlight recent insights into the structures of the plant immune and bacterial virulence networks and the interactions between them. We propose that small molecules derived from plants and/or bacterial pathogens connect the two molecular networks, forming supernetworks in the plant-bacterial pathogen holobiont.}, }
@article {pmid29701776, year = {2018}, author = {Karimi, E and Slaby, BM and Soares, AR and Blom, J and Hentschel, U and Costa, R}, title = {Metagenomic binning reveals versatile nutrient cycling and distinct adaptive features in alphaproteobacterial symbionts of marine sponges.}, journal = {FEMS microbiology ecology}, volume = {94}, number = {6}, pages = {}, doi = {10.1093/femsec/fiy074}, pmid = {29701776}, issn = {1574-6941}, abstract = {Marine sponges are early-branched metazoans known to harbor dense and diverse microbial communities. Yet the role of the so far uncultivable alphaproteobacterial lineages that populate these sessile invertebrates remains unclear. We applied a sequence composition-dependent binning approach to assemble one Rhodospirillaceae genome from the Spongia officinalis microbial metagenome and contrast its functional features with those of closely related sponge-associated and free-living genomes. Both symbiotic and free-living Rhodospirillaceae shared a suite of common features, possessing versatile carbon, nitrogen, sulfur and phosphorus metabolisms. Symbiotic genomes could be distinguished from their free-living counterparts by the lack of chemotaxis and motility traits, enrichment of genes required for the uptake and utilization of organic sulfur compounds-particularly taurine-, higher diversity and abundance of ABC transporters, and a distinct repertoire of genes involved in natural product biosynthesis, plasmid stability, cell detoxification and oxidative stress remediation. These sessile symbionts may more effectively contribute to host fitness via nutrient exchange, and also host detoxification and chemical defense. Considering the worldwide occurrence and high diversity of sponge-associated Rhodospirillaceae verified here using a tailored in silico approach, we suggest that these organisms are not only relevant to holobiont homeostasis but also to nutrient cycling in benthic ecosystems.}, }
@article {pmid29695294, year = {2018}, author = {Rosenberg, E and Zilber-Rosenberg, I}, title = {The hologenome concept of evolution after 10 years.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {78}, doi = {10.1186/s40168-018-0457-9}, pmid = {29695294}, issn = {2049-2618}, abstract = {The holobiont (host with its endocellular and extracellular microbiome) can function as a distinct biological entity, an additional organismal level to the ones previously considered, on which natural selection operates. The holobiont can function as a whole: anatomically, metabolically, immunologically, developmentally, and during evolution. Consideration of the holobiont with its hologenome as an independent level of selection in evolution has led to a better understanding of underappreciated modes of genetic variation and evolution. The hologenome is comprised of two complimentary parts: host and microbiome genomes. Changes in either genome can result in variations that can be selected for or against. The host genome is highly conserved, and genetic changes within it occur slowly, whereas the microbiome genome is dynamic and can change rapidly in response to the environment by increasing or reducing particular microbes, by acquisition of novel microbes, by horizontal gene transfer, and by mutation. Recent experiments showing that microbiota can play an initial role in speciation have been suggested as an additional mode of enhancing evolution. Some of the genetic variations can be transferred to offspring by a variety of mechanisms. Strain-specific DNA analysis has shown that at least some of the microbiota can be maintained across hundreds of thousands of host generations, implying the existence of a microbial core. We argue that rapid changes in the microbiome genome could allow holobionts to adapt and survive under changing environmental conditions thus providing the time necessary for the host genome to adapt and evolve. As Darwin wrote, &quot;It is not the strongest of the species that survives but the most adaptable&quot;.}, }
@article {pmid29695286, year = {2018}, author = {Vannier, N and Mony, C and Bittebiere, AK and Michon-Coudouel, S and Biget, M and Vandenkoornhuyse, P}, title = {A microorganisms' journey between plant generations.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {79}, doi = {10.1186/s40168-018-0459-7}, pmid = {29695286}, issn = {2049-2618}, support = {EC2CO program (MIME project)//Centre National de la Recherche Scientifique/ ; PEPS program (MYCOLAND project)//Centre National de la Recherche Scientifique/ ; }, abstract = {BACKGROUND: Plants are colonized by a great diversity of microorganisms which form a microbiota and perform additional functions for their host. This microbiota can thus be considered a toolbox enabling plants to buffer local environmental changes, with a positive influence on plant fitness. In this context, the transmission of the microbiota to the progeny represent a way to ensure the presence of beneficial symbionts within the habitat. Examples of such transmission have been mainly described for seed transmission and concern a few pathogenic microorganisms. We investigated the transmission of symbiotic partners to plant progeny within clonal plant network.<br><br>METHODS: We used the clonal plant Glechoma hederacea as plant model and forced newly emitted clonal progeny to root in separated pots while controlling the presence of microorganisms. We used an amplicon sequencing approach of 16S and 18S rRNA targeting bacteria/archaea and fungi respectively to describe the root microbiota of mother and clonal-plant offspring.<br><br>RESULTS: We demonstrated the vertical transmission of a significant proportion of the mother plants' symbiotic bacteria and fungi to the daughters. Interestingly, archaea were not transmitted to the daughter plants. Transmitted communities had lower richness, suggesting a filtration during transmission. We found that the transmitted pool of microorganisms was similar among daughters, constituting the heritability of a specific cohort of microorganisms, opening a new understanding of the plant holobiont. We also found significant effects of distance to the mother plant and of growth time on the richness of the microbiota transmitted.<br><br>CONCLUSIONS: In this clonal plant, microorganisms are transmitted between individuals through connections, thereby ensuring the availability of microbe partners for the newborn plants as well as the dispersion between hosts for the microorganisms. This previously undescribed ecological process allows the dispersal of microorganisms in space and across plant generations. As the vast majority of plants are clonal, this process might be therefore a strong driver of ecosystem functioning and assembly of plant and microorganism communities in a wide range of ecosystems.}, }
@article {pmid29666616, year = {2018}, author = {Mortzfeld, BM and Taubenheim, J and Fraune, S and Klimovich, AV and Bosch, TCG}, title = {Stem Cell Transcription Factor FoxO Controls Microbiome Resilience in Hydra.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {629}, doi = {10.3389/fmicb.2018.00629}, pmid = {29666616}, issn = {1664-302X}, abstract = {The aging process is considered to be the result of accumulating cellular deterioration in an individual organism over time. It can be affected by the combined influence of genetic, epigenetic, and environmental factors including life-style-associated events. In the non-senescent freshwater polyp Hydra, one of the classical model systems for evolutionary developmental biology and regeneration, transcription factor FoxO modulates both stem cell proliferation and innate immunity. This provides strong support for the role of FoxO as a critical rate-of-aging regulator. However, how environmental factors interact with FoxO remains unknown. Here, we find that deficiency in FoxO signaling in Hydra leads to dysregulation of antimicrobial peptide expression and that FoxO loss-of-function polyps are impaired in selection for bacteria resembling the native microbiome and more susceptible to colonization of foreign bacteria. These findings reveal a key role of FoxO signaling in the communication between host and microbiota and embed the evolutionary conserved longevity factor FoxO into the holobiont concept.}, }
@article {pmid29657963, year = {2018}, author = {Theis, KR}, title = {Hologenomics: Systems-Level Host Biology.}, journal = {mSystems}, volume = {3}, number = {2}, pages = {}, doi = {10.1128/mSystems.00164-17}, pmid = {29657963}, issn = {2379-5077}, abstract = {The hologenome concept of evolution is a hypothesis explaining host evolution in the context of the host microbiomes. As a hypothesis, it needs to be evaluated, especially with respect to the extent of fidelity of transgenerational coassociation of host and microbial lineages and the relative fitness consequences of repeated associations within natural holobiont populations. Behavioral ecologists are in a prime position to test these predictions because they typically focus on animal phenotypes that are quantifiable, conduct studies over multiple generations within natural animal populations, and collect metadata on genetic relatedness and relative reproductive success within these populations. Regardless of the conclusion on the hologenome concept as an evolutionary hypothesis, a hologenomic perspective has applied value as a systems-level framework for host biology, including in medicine. Specifically, it emphasizes investigating the multivarious and dynamic interactions between patient genomes and the genomes of their diverse microbiota when attempting to elucidate etiologies of complex, noninfectious diseases.}, }
@article {pmid29651978, year = {2018}, author = {Vigliotti, C and Bicep, C and Bapteste, E and Lopez, P and Corel, E}, title = {Tracking the Rules of Transmission and Introgression with Networks.}, journal = {Microbiology spectrum}, volume = {6}, number = {2}, pages = {}, doi = {10.1128/microbiolspec.MTBP-0008-2016}, pmid = {29651978}, issn = {2165-0497}, abstract = {Understanding how an animal organism and its gut microbes form an integrated biological organization, known as a holobiont, is becoming a central issue in biological studies. Such an organization inevitably involves a complex web of transmission processes that occur on different scales in time and space, across microbes and hosts. Network-based models are introduced in this chapter to tackle aspects of this complexity and to better take into account vertical and horizontal dimensions of transmission. Two types of network-based models are presented, sequence similarity networks and bipartite graphs. One interest of these networks is that they can consider a rich diversity of important players in microbial evolution that are usually excluded from evolutionary studies, like plasmids and viruses. These methods bring forward the notion of &quot;gene externalization,&quot; which is defined as the presence of redundant copies of prokaryotic genes on mobile genetic elements (MGEs), and therefore emphasizes a related although distinct process from lateral gene transfer between microbial cells. This chapter introduces guidelines to the construction of these networks, reviews their analysis, and illustrates their possible biological interpretations and uses. The application to human gut microbiomes shows that sequences present in a higher diversity of MGEs have both biased functions and a broader microbial and human host range. These results suggest that an &quot;externalized gut metagenome&quot; is partly common to humans and benefits the gut microbial community. We conclude that testing relationships between microbial genes, microbes, and their animal hosts, using network-based methods, could help to unravel additional mechanisms of transmission in holobionts.}, }
@article {pmid29650460, year = {2018}, author = {Allemand, D and Furla, P}, title = {How does an animal behave like a plant? Physiological and molecular adaptations of zooxanthellae and their hosts to symbiosis.}, journal = {Comptes rendus biologies}, volume = {341}, number = {5}, pages = {276-280}, doi = {10.1016/j.crvi.2018.03.007}, pmid = {29650460}, issn = {1768-3238}, abstract = {Cnidarians (corals and sea anemones) harbouring photosynthetic microalgae derive several benefits from their association. To allow this association, numerous symbiotic-dependent adaptations in both partners, resulting from evolutionary pressures, have been selected. The dinoflagellate symbionts (zooxanthellae) are located inside a vesicle in the cnidarian host cell and are therefore exposed to a very different environment compared to the free-living state of these microalgae in terms of ion concentration and carbon content and speciation. In addition, this intracellular localization imposes that they rely completely upon the host for their nutrient supply (nitrogen, CO2). Symbiotic-dependent adaptations imposed to the animal host by phototrophic symbiosis are more relevant to photosynthetic organisms than to metazoans: indeed, the cnidarian host often harbours diurnal changes of morphology to adapt itself to the amount of light and possesses carbon-concentrating mechanisms, antioxidative defences and UV sunscreens similar to that present in phototrophs. These adaptations and the contrasting fragility of the association are discussed from both ecological and evolutionary points of view.}, }
@article {pmid29645277, year = {2018}, author = {Wille, L and Messmer, MM and Studer, B and Hohmann, P}, title = {Insights to plant-microbe interactions provide opportunities to improve resistance breeding against root diseases in grain legumes.}, journal = {Plant, cell &amp; environment}, volume = {}, number = {}, pages = {}, doi = {10.1111/pce.13214}, pmid = {29645277}, issn = {1365-3040}, abstract = {Root and foot diseases severely impede grain legume cultivation worldwide. Breeding lines with resistance against individual pathogens exist, but these resistances are often overcome by the interaction of multiple pathogens in field situations. Novel tools allow to decipher plant-microbiome interactions in unprecedented detail and provide insights into resistance mechanisms that consider both simultaneous attacks of various pathogens and the interplay with beneficial microbes. Although it has become clear that plant-associated microbes play a key role in plant health, a systematic picture of how and to what extent plants can shape their own detrimental or beneficial microbiome remains to be drawn. There is increasing evidence for the existence of genetic variation in the regulation of plant-microbe interactions that can be exploited by plant breeders. We propose to consider the entire plant holobiont in resistance breeding strategies in order to unravel hidden parts of complex defence mechanisms. This review summarizes (a) the current knowledge of resistance against soil-borne pathogens in grain legumes, (b) evidence for genetic variation for rhizosphere-related traits, (c) the role of root exudation in microbe-mediated disease resistance and elaborates (d) how these traits can be incorporated in resistance breeding programmes.}, }
@article {pmid29615919, year = {2018}, author = {Rädecker, N and Raina, JB and Pernice, M and Perna, G and Guagliardo, P and Kilburn, MR and Aranda, M and Voolstra, CR}, title = {Using Aiptasia as a Model to Study Metabolic Interactions in Cnidarian-Symbiodinium Symbioses.}, journal = {Frontiers in physiology}, volume = {9}, number = {}, pages = {214}, doi = {10.3389/fphys.2018.00214}, pmid = {29615919}, issn = {1664-042X}, abstract = {The symbiosis between cnidarian hosts and microalgae of the genus Symbiodinium provides the foundation of coral reefs in oligotrophic waters. Understanding the nutrient-exchange between these partners is key to identifying the fundamental mechanisms behind this symbiosis, yet has proven difficult given the endosymbiotic nature of this relationship. In this study, we investigated the respective contribution of host and symbiont to carbon and nitrogen assimilation in the coral model anemone Aiptaisa. For this, we combined traditional measurements with nanoscale secondary ion mass spectrometry (NanoSIMS) and stable isotope labeling to investigate patterns of nutrient uptake and translocation both at the organismal scale and at the cellular scale. Our results show that the rate of carbon and nitrogen assimilation in Aiptasia depends on the identity of the host and the symbiont. NanoSIMS analysis confirmed that both host and symbiont incorporated carbon and nitrogen into their cells, implying a rapid uptake and cycling of nutrients in this symbiotic relationship. Gross carbon fixation was highest in Aiptasia associated with their native Symbiodinium communities. However, differences in fixation rates were only reflected in the δ13C enrichment of the cnidarian host, whereas the algal symbiont showed stable enrichment levels regardless of host identity. Thereby, our results point toward a &quot;selfish&quot; character of the cnidarian-Symbiodinium association in which both partners directly compete for available resources. Consequently, this symbiosis may be inherently instable and highly susceptible to environmental change. While questions remain regarding the underlying cellular controls of nutrient exchange and the nature of metabolites involved, the approach outlined in this study constitutes a powerful toolset to address these questions.}, }
@article {pmid29611114, year = {2018}, author = {Wang, J and Chen, L and Zhao, N and Xu, X and Xu, Y and Zhu, B}, title = {Of genes and microbes: solving the intricacies in host genomes.}, journal = {Protein &amp; cell}, volume = {9}, number = {5}, pages = {446-461}, doi = {10.1007/s13238-018-0532-9}, pmid = {29611114}, issn = {1674-8018}, abstract = {Microbiome research is a quickly developing field in biomedical research, and we have witnessed its potential in understanding the physiology, metabolism and immunology, its critical role in understanding the health and disease of the host, and its vast capacity in disease prediction, intervention and treatment. However, many of the fundamental questions still need to be addressed, including the shaping forces of microbial diversity between individuals and across time. Microbiome research falls into the classical nature vs. nurture scenario, such that host genetics shape part of the microbiome, while environmental influences change the original course of microbiome development. In this review, we focus on the nature, i.e., the genetic part of the equation, and summarize the recent efforts in understanding which parts of the genome, especially the human and mouse genome, play important roles in determining the composition and functions of microbial communities, primarily in the gut but also on the skin. We aim to present an overview of different approaches in studying the intricate relationships between host genetic variations and microbes, its underlying philosophy and methodology, and we aim to highlight a few key discoveries along this exploration, as well as current pitfalls. More evidence and results will surely appear in upcoming studies, and the accumulating knowledge will lead to a deeper understanding of what we could finally term a &quot;hologenome&quot;, that is, the organized, closely interacting genome of the host and the microbiome.}, }
@article {pmid29609655, year = {2018}, author = {van de Water, JAJM and Allemand, D and Ferrier-Pagès, C}, title = {Host-microbe interactions in octocoral holobionts - recent advances and perspectives.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {64}, doi = {10.1186/s40168-018-0431-6}, pmid = {29609655}, issn = {2049-2618}, abstract = {Octocorals are one of the most ubiquitous benthic organisms in marine ecosystems from the shallow tropics to the Antarctic deep sea, providing habitat for numerous organisms as well as ecosystem services for humans. In contrast to the holobionts of reef-building scleractinian corals, the holobionts of octocorals have received relatively little attention, despite the devastating effects of disease outbreaks on many populations. Recent advances have shown that octocorals possess remarkably stable bacterial communities on geographical and temporal scales as well as under environmental stress. This may be the result of their high capacity to regulate their microbiome through the production of antimicrobial and quorum-sensing interfering compounds. Despite decades of research relating to octocoral-microbe interactions, a synthesis of this expanding field has not been conducted to date. We therefore provide an urgently needed review on our current knowledge about octocoral holobionts. Specifically, we briefly introduce the ecological role of octocorals and the concept of holobiont before providing detailed overviews of (I) the symbiosis between octocorals and the algal symbiont Symbiodinium; (II) the main fungal, viral, and bacterial taxa associated with octocorals; (III) the dominance of the microbial assemblages by a few microbial species, the stability of these associations, and their evolutionary history with the host organism; (IV) octocoral diseases; (V) how octocorals use their immune system to fight pathogens; (VI) microbiome regulation by the octocoral and its associated microbes; and (VII) the discovery of natural products with microbiome regulatory activities. Finally, we present our perspectives on how the field of octocoral research should move forward, and the recognition that these organisms may be suitable model organisms to study coral-microbe symbioses.}, }
@article {pmid29599012, year = {2018}, author = {Bang, C and Dagan, T and Deines, P and Dubilier, N and Duschl, WJ and Fraune, S and Hentschel, U and Hirt, H and Hülter, N and Lachnit, T and Picazo, D and Pita, L and Pogoreutz, C and Rädecker, N and Saad, MM and Schmitz, RA and Schulenburg, H and Voolstra, CR and Weiland-Bräuer, N and Ziegler, M and Bosch, TCG}, title = {Metaorganisms in extreme environments: do microbes play a role in organismal adaptation?.}, journal = {Zoology (Jena, Germany)}, volume = {127}, number = {}, pages = {1-19}, doi = {10.1016/j.zool.2018.02.004}, pmid = {29599012}, issn = {1873-2720}, mesh = {*Adaptation, Physiological/physiology ; Animals ; Ecosystem ; *Extreme Environments ; Microbiota/genetics/*physiology ; Phylogeny ; Symbiosis/physiology ; }, abstract = {From protists to humans, all animals and plants are inhabited by microbial organisms. There is an increasing appreciation that these resident microbes influence the fitness of their plant and animal hosts, ultimately forming a metaorganism consisting of a uni- or multicellular host and a community of associated microorganisms. Research on host-microbe interactions has become an emerging cross-disciplinary field. In both vertebrates and invertebrates a complex microbiome confers immunological, metabolic and behavioural benefits; conversely, its disturbance can contribute to the development of disease states. However, the molecular and cellular mechanisms controlling the interactions within a metaorganism are poorly understood and many key interactions between the associated organisms remain unknown. In this perspective article, we outline some of the issues in interspecies interactions and in particular address the question of how metaorganisms react and adapt to inputs from extreme environments such as deserts, the intertidal zone, oligothrophic seas, and hydrothermal vents.}, }
@article {pmid29587885, year = {2018}, author = {Hassani, MA and Durán, P and Hacquard, S}, title = {Microbial interactions within the plant holobiont.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {58}, doi = {10.1186/s40168-018-0445-0}, pmid = {29587885}, issn = {2049-2618}, support = {758003//European Research Council/International ; }, abstract = {Since the colonization of land by ancestral plant lineages 450 million years ago, plants and their associated microbes have been interacting with each other, forming an assemblage of species that is often referred to as a &quot;holobiont.&quot; Selective pressure acting on holobiont components has likely shaped plant-associated microbial communities and selected for host-adapted microorganisms that impact plant fitness. However, the high microbial densities detected on plant tissues, together with the fast generation time of microbes and their more ancient origin compared to their host, suggest that microbe-microbe interactions are also important selective forces sculpting complex microbial assemblages in the phyllosphere, rhizosphere, and plant endosphere compartments. Reductionist approaches conducted under laboratory conditions have been critical to decipher the strategies used by specific microbes to cooperate and compete within or outside plant tissues. Nonetheless, our understanding of these microbial interactions in shaping more complex plant-associated microbial communities, along with their relevance for host health in a more natural context, remains sparse. Using examples obtained from reductionist and community-level approaches, we discuss the fundamental role of microbe-microbe interactions (prokaryotes and micro-eukaryotes) for microbial community structure and plant health. We provide a conceptual framework illustrating that interactions among microbiota members are critical for the establishment and the maintenance of host-microbial homeostasis.}, }
@article {pmid29587830, year = {2018}, author = {Gobet, A and Mest, L and Perennou, M and Dittami, SM and Caralp, C and Coulombet, C and Huchette, S and Roussel, S and Michel, G and Leblanc, C}, title = {Seasonal and algal diet-driven patterns of the digestive microbiota of the European abalone Haliotis tuberculata, a generalist marine herbivore.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {60}, doi = {10.1186/s40168-018-0430-7}, pmid = {29587830}, issn = {2049-2618}, support = {ANR-10-BTBR-02-04-11//Agence Nationale de la Recherche/ ; }, abstract = {BACKGROUND: Holobionts have a digestive microbiota with catabolic abilities allowing the degradation of complex dietary compounds for the host. In terrestrial herbivores, the digestive microbiota is known to degrade complex polysaccharides from land plants while in marine herbivores, the digestive microbiota is poorly characterized. Most of the latter are generalists and consume red, green, and brown macroalgae, three distinct lineages characterized by a specific composition in complex polysaccharides, which represent half of their biomass. Subsequently, each macroalga features a specific epiphytic microbiota, and the digestive microbiota of marine herbivores is expected to vary with a monospecific algal diet. We investigated the effect of four monospecific diets (Palmaria palmata, Ulva lactuca, Saccharina latissima, Laminaria digitata) on the composition and specificity of the digestive microbiota of a generalist marine herbivore, the abalone, farmed in a temperate coastal area over a year. The microbiota from the abalone digestive gland was sampled every 2 months and explored using metabarcoding.<br><br>RESULTS: Diversity and multivariate analyses showed that patterns of the microbiota were significantly linked to seasonal variations of contextual parameters but not directly to a specific algal diet. Three core genera: Psychrilyobacter, Mycoplasma, and Vibrio constantly dominated the microbiota in the abalone digestive gland. Additionally, a less abundant and diet-specific core microbiota featured genera representing aerobic primary degraders of algal polysaccharides.<br><br>CONCLUSIONS: This study highlights the establishment of a persistent core microbiota in the digestive gland of the abalone since its juvenile state and the presence of a less abundant and diet-specific core community. While composed of different microbial taxa compared to terrestrial herbivores, the digestive gland constitutes a particular niche in the abalone holobiont, where bacteria (i) may cooperate to degrade algal polysaccharides to products assimilable by the host or (ii) may have acquired these functions through gene transfer from the aerobic algal microbiota.}, }
@article {pmid29573244, year = {2018}, author = {Pootakham, W and Mhuantong, W and Putchim, L and Yoocha, T and Sonthirod, C and Kongkachana, W and Sangsrakru, D and Naktang, C and Jomchai, N and Thongtham, N and Tangphatsornruang, S}, title = {Dynamics of coral-associated microbiomes during a thermal bleaching event.}, journal = {MicrobiologyOpen}, volume = {}, number = {}, pages = {e00604}, doi = {10.1002/mbo3.604}, pmid = {29573244}, issn = {2045-8827}, abstract = {Coral-associated microorganisms play an important role in their host fitness and survival. A number of studies have demonstrated connections between thermal tolerance in corals and the type/relative abundance of Symbiodinium they harbor. More recently, the shifts in coral-associated bacterial profiles were also shown to be linked to the patterns of coral heat tolerance. Here, we investigated the dynamics of Porites lutea-associated bacterial and algal communities throughout a natural bleaching event, using full-length 16S rRNA and internal transcribed spacer sequences (ITS) obtained from PacBio circular consensus sequencing. We provided evidence of significant changes in the structure and diversity of coral-associated microbiomes during thermal stress. The balance of the symbiosis shifted from a predominant association between corals and Gammaproteobacteria to a predominance of Alphaproteobacteria and to a lesser extent Betaproteobacteria following the bleaching event. On the contrary, the composition and diversity of Symbiodinium communities remained unaltered throughout the bleaching event. It appears that the switching and/or shuffling of Symbiodinium types may not be the primary mechanism used by P. lutea to cope with increasing seawater temperature. The shifts in the structure and diversity of associated bacterial communities may contribute more to the survival of the coral holobiont under heat stress.}, }
@article {pmid29567394, year = {2018}, author = {Rahman, MM and Flory, E and Koyro, HW and Abideen, Z and Schikora, A and Suarez, C and Schnell, S and Cardinale, M}, title = {Consistent associations with beneficial bacteria in the seed endosphere of barley (Hordeum vulgare L.).}, journal = {Systematic and applied microbiology}, volume = {41}, number = {4}, pages = {386-398}, doi = {10.1016/j.syapm.2018.02.003}, pmid = {29567394}, issn = {1618-0984}, abstract = {The importance of the plant microbiome for host fitness has led to the concept of the &quot;plant holobiont&quot;. Seeds are reservoirs and vectors for beneficial microbes, which are very intimate partners of higher plants with the potential to connect plant generations. In this study, the endophytic seed microbiota of numerous barley samples, representing different cultivars, geographical sites and harvest years, was investigated. Cultivation-dependent and -independent analyses, microscopy, functional plate assays, greenhouse assays and functional prediction were used, with the aim of assessing the composition, stability and function of the barley seed endophytic bacterial microbiota. Associations were consistently detected in the seed endosphere with Paenibacillus, Pantoea and Pseudomonas spp., which were able to colonize the root with a notable rhizocompetence after seed germination. In greenhouse assays, enrichment with these bacteria promoted barley growth, improved mineral nutrition and induced resistance against the fungal pathogen Blumeria graminis. We demonstrated here that barley, an important crop plant, was consistently associated with beneficial bacteria inside the seeds. The results have relevant implications for plant microbiome ecology and for the holobiont concept, as well as opening up new possibilities for research and application of seed endophytes as bioinoculants in sustainable agriculture.}, }
@article {pmid29566771, year = {2018}, author = {Callens, M and Watanabe, H and Kato, Y and Miura, J and Decaestecker, E}, title = {Microbiota inoculum composition affects holobiont assembly and host growth in Daphnia.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {56}, doi = {10.1186/s40168-018-0444-1}, pmid = {29566771}, issn = {2049-2618}, support = {FWO G060216N//FWO/ ; BOF C16/17/002//KU Leuven/ ; }, abstract = {BACKGROUND: Host-associated microbiota is often acquired by horizontal transmission of microbes present in the environment. It is hypothesized that differences in the environmental pool of colonizers can influence microbiota community assembly on the host and as such affect holobiont composition and host fitness. To investigate this hypothesis, the host-associated microbiota of the invertebrate eco(toxico)logical model Daphnia was experimentally disturbed using different concentrations of the antibiotic oxytetracycline. The community assembly and host-microbiota interactions when Daphnia were colonized by the disturbed microbiota were investigated by inoculating germ-free individuals with the microbiota.<br><br>RESULTS: Antibiotic-induced disturbance of the microbiota had a strong effect on the subsequent colonization of Daphnia by affecting ecological interactions between members of the microbiota. This resulted in differences in community assembly which, in turn, affected Daphnia growth.<br><br>CONCLUSIONS: These results show that the composition of the pool of colonizing microbiota can be an important structuring factor of the microbiota assembly on Daphnia, affecting holobiont composition and host growth. These findings contribute to a better understanding of how the microbial environment can shape the holobiont composition and affect host-microbiota interactions.}, }
@article {pmid29562933, year = {2018}, author = {Ravanbakhsh, M and Sasidharan, R and Voesenek, LACJ and Kowalchuk, GA and Jousset, A}, title = {Microbial modulation of plant ethylene signaling: ecological and evolutionary consequences.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {52}, doi = {10.1186/s40168-018-0436-1}, pmid = {29562933}, issn = {2049-2618}, abstract = {The plant hormone ethylene is one of the central regulators of plant development and stress resistance. Optimal ethylene signaling is essential for plant fitness and is under strong selection pressure. Plants upregulate ethylene production in response to stress, and this hormone triggers defense mechanisms. Due to the pleiotropic effects of ethylene, adjusting stress responses to maximize resistance, while minimizing costs, is a central determinant of plant fitness. Ethylene signaling is influenced by the plant-associated microbiome. We therefore argue that the regulation, physiology, and evolution of the ethylene signaling can best be viewed as the interactive result of plant genotype and associated microbiota. In this article, we summarize the current knowledge on ethylene signaling and recapitulate the multiple ways microorganisms interfere with it. We present ethylene signaling as a model system for holobiont-level evolution of plant phenotype: this cascade is tractable, extremely well studied from both a plant and a microbial perspective, and regulates fundamental components of plant life history. We finally discuss the potential impacts of ethylene modulation microorganisms on plant ecology and evolution. We assert that ethylene signaling cannot be fully appreciated without considering microbiota as integral regulatory actors, and we more generally suggest that plant ecophysiology and evolution can only be fully understood in the light of plant-microbiome interactions.}, }
@article {pmid29556542, year = {2018}, author = {Wegley Kelly, L and Haas, AF and Nelson, CE}, title = {Ecosystem Microbiology of Coral Reefs: Linking Genomic, Metabolomic, and Biogeochemical Dynamics from Animal Symbioses to Reefscape Processes.}, journal = {mSystems}, volume = {3}, number = {2}, pages = {}, doi = {10.1128/mSystems.00162-17}, pmid = {29556542}, issn = {2379-5077}, abstract = {Over the past 2 decades, molecular techniques have established the critical role of both free-living and host-associated microbial partnerships in the environment. Advancing research to link microbial community dynamics simultaneously to host physiology and ecosystem biogeochemistry is required to broaden our understanding of the ecological roles of environmental microbes. Studies on coral reefs are actively integrating these data streams at multiple levels, from the symbiotic habitat of the coral holobiont to microbially mediated interactions between corals and algae to the effects of these interactions on the microbial community structure, metabolism, and organic geochemistry of the reef ecosystem. Coral reefs endure multiple anthropogenic impacts, including pollution, overfishing, and global change. In this context, we must develop ecosystem microbiology with an eye to providing managers with microbial indicators of reef ecosystem processes, coral health, and resilience to both local and global stressors.}, }
@article {pmid29554951, year = {2018}, author = {Guégan, M and Zouache, K and Démichel, C and Minard, G and Tran Van, V and Potier, P and Mavingui, P and Valiente Moro, C}, title = {The mosquito holobiont: fresh insight into mosquito-microbiota interactions.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {49}, doi = {10.1186/s40168-018-0435-2}, pmid = {29554951}, issn = {2049-2618}, abstract = {The holobiont concept was first developed for coral ecosystems but has been extended to multiple organisms, including plants and other animals. Studies on insect-associated microbial communities have produced strong evidence that symbiotic bacteria play a major role in host biology. However, the understanding of these symbiotic relationships has mainly been limited to phytophagous insects, while the role of host-associated microbiota in haematophagous insect vectors remains largely unexplored. Mosquitoes are a major global public health concern, with a concomitant increase in people at risk of infection. The global emergence and re-emergence of mosquito-borne diseases has led many researchers to study both the mosquito host and its associated microbiota. Although most of these studies have been descriptive, they have led to a broad description of the bacterial communities hosted by mosquito populations. This review describes key advances and progress in the field of the mosquito microbiota research while also encompassing other microbes and the environmental factors driving their composition and diversity. The discussion includes recent findings on the microbiota functional roles and underlines their interactions with the host biology and pathogen transmission. Insight into the ecology of multipartite interactions, we consider that conferring the term holobiont to the mosquito and its microbiota is useful to get a comprehensive understanding of the vector pathosystem functioning so as to be able to develop innovative and efficient novel vector control strategies.}, }
@article {pmid29546438, year = {2018}, author = {Rua, CPJ and de Oliveira, LS and Froes, A and Tschoeke, DA and Soares, AC and Leomil, L and Gregoracci, GB and Coutinho, R and Hajdu, E and Thompson, CC and Berlinck, RGS and Thompson, FL}, title = {Microbial and Functional Biodiversity Patterns in Sponges that Accumulate Bromopyrrole Alkaloids Suggest Horizontal Gene Transfer of Halogenase Genes.}, journal = {Microbial ecology}, volume = {}, number = {}, pages = {}, doi = {10.1007/s00248-018-1172-6}, pmid = {29546438}, issn = {1432-184X}, support = {CNE E-26/110.735/2013//Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro/ ; CIMAR 1986/2014//Coordenação de Aperfeiçoamento de Pessoal de Nível Superior/ ; BIOTA/BIOprospecTA grant 2013/50228-8//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; 2014/17616- 7//Fundação de Amparo à Pesquisa do Estado de São Paulo/ ; }, abstract = {Marine sponge holobionts harbor complex microbial communities whose members may be the true producers of secondary metabolites accumulated by sponges. Bromopyrrole alkaloids constitute a typical class of secondary metabolites isolated from sponges that very often display biological activities. Bromine incorporation into secondary metabolites can be catalyzed by either halogenases or haloperoxidases. The diversity of the metagenomes of sponge holobiont species containing bromopyrrole alkaloids (Agelas spp. and Tedania brasiliensis) as well as holobionts devoid of bromopyrrole alkaloids spanning in a vast biogeographic region (approx. Seven thousand km) was studied. The origin and specificity of the detected halogenases was also investigated. The holobionts Agelas spp. and T. brasiliensis did not share microbial halogenases, suggesting a species-specific pattern. Bacteria of diverse phylogenetic origins encoding halogenase genes were found to be more abundant in bromopyrrole-containing sponges. The sponge holobionts (e.g., Agelas spp.) with the greatest number of sequences related to clustered, interspaced, short, palindromic repeats (CRISPRs) exhibited the fewest phage halogenases, suggesting a possible mechanism of protection from phage infection by the sponge host. This study highlights the potential of phages to transport halogenases horizontally across host sponges, particularly in more permissive holobiont hosts, such as Tedania spp.}, }
@article {pmid29540239, year = {2018}, author = {Sevellec, M and Derome, N and Bernatchez, L}, title = {Holobionts and ecological speciation: the intestinal microbiota of lake whitefish species pairs.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {47}, doi = {10.1186/s40168-018-0427-2}, pmid = {29540239}, issn = {2049-2618}, abstract = {BACKGROUND: It is well established that symbionts have considerable impact on their host, yet the investigation of the possible role of the holobiont in the host's speciation process is still in its infancy. In this study, we compared the intestinal microbiota among five sympatric pairs of dwarf (limnetic) and normal (benthic) lake whitefish Coregonus clupeaformis representing a continuum in the early stage of ecological speciation. We sequenced the 16s rRNA gene V3-V4 regions of the intestinal microbiota present in a total of 108 wild sympatric dwarf and normal whitefish as well as the water bacterial community from five lakes to (i) test for differences between the whitefish intestinal microbiota and the water bacterial community and (ii) test for parallelism in the intestinal microbiota of dwarf and normal whitefish.<br><br>RESULTS: The water bacterial community was distinct from the intestinal microbiota, indicating that intestinal microbiota did not reflect the environment, but rather the intrinsic properties of the host microbiota. Our results revealed a strong influence of the host (dwarf or normal) on the intestinal microbiota with pronounced conservation of the core intestinal microbiota (mean ~ 44% of shared genera). However, no clear evidence for parallelism was observed, whereby non-parallel differences between dwarf and normal whitefish were observed in three of the lakes while similar taxonomic composition was observed for the two other species pairs.<br><br>CONCLUSIONS: This absence of parallelism across dwarf vs. normal whitefish microbiota highlighted the complexity of the holobiont and suggests that the direction of selection could be different between the host and its microbiota.}, }
@article {pmid29523192, year = {2018}, author = {Pita, L and Rix, L and Slaby, BM and Franke, A and Hentschel, U}, title = {The sponge holobiont in a changing ocean: from microbes to ecosystems.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {46}, doi = {10.1186/s40168-018-0428-1}, pmid = {29523192}, issn = {2049-2618}, support = {679849//Horizon 2020/ ; 679849//Horizon 2020/ ; CRC1182-TPB1//Deutsche Forschungsgemeinschaft/ ; }, abstract = {The recognition that all macroorganisms live in symbiotic association with microbial communities has opened up a new field in biology. Animals, plants, and algae are now considered holobionts, complex ecosystems consisting of the host, the microbiota, and the interactions among them. Accordingly, ecological concepts can be applied to understand the host-derived and microbial processes that govern the dynamics of the interactive networks within the holobiont. In marine systems, holobionts are further integrated into larger and more complex communities and ecosystems, a concept referred to as &quot;nested ecosystems.&quot; In this review, we discuss the concept of holobionts as dynamic ecosystems that interact at multiple scales and respond to environmental change. We focus on the symbiosis of sponges with their microbial communities-a symbiosis that has resulted in one of the most diverse and complex holobionts in the marine environment. In recent years, the field of sponge microbiology has remarkably advanced in terms of curated databases, standardized protocols, and information on the functions of the microbiota. Like a Russian doll, these microbial processes are translated into sponge holobiont functions that impact the surrounding ecosystem. For example, the sponge-associated microbial metabolisms, fueled by the high filtering capacity of the sponge host, substantially affect the biogeochemical cycling of key nutrients like carbon, nitrogen, and phosphorous. Since sponge holobionts are increasingly threatened by anthropogenic stressors that jeopardize the stability of the holobiont ecosystem, we discuss the link between environmental perturbations, dysbiosis, and sponge diseases. Experimental studies suggest that the microbial community composition is tightly linked to holobiont health, but whether dysbiosis is a cause or a consequence of holobiont collapse remains unresolved. Moreover, the potential role of the microbiome in mediating the capacity for holobionts to acclimate and adapt to environmental change is unknown. Future studies should aim to identify the mechanisms underlying holobiont dynamics at multiple scales, from the microbiome to the ecosystem, and develop management strategies to preserve the key functions provided by the sponge holobiont in our present and future oceans.}, }
@article {pmid29507840, year = {2018}, author = {Brüwer, JD and Voolstra, CR}, title = {First insight into the viral community of the cnidarian model metaorganism Aiptasia using RNA-Seq data.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e4449}, doi = {10.7717/peerj.4449}, pmid = {29507840}, issn = {2167-8359}, abstract = {Current research posits that all multicellular organisms live in symbioses with associated microorganisms and form so-called metaorganisms or holobionts. Cnidarian metaorganisms are of specific interest given that stony corals provide the foundation of the globally threatened coral reef ecosystems. To gain first insight into viruses associated with the coral model system Aiptasia (sensu Exaiptasia pallida), we analyzed an existing RNA-Seq dataset of aposymbiotic, partially populated, and fully symbiotic Aiptasia CC7 anemones with Symbiodinium. Our approach included the selective removal of anemone host and algal endosymbiont sequences and subsequent microbial sequence annotation. Of a total of 297 million raw sequence reads, 8.6 million (∼3%) remained after host and endosymbiont sequence removal. Of these, 3,293 sequences could be assigned as of viral origin. Taxonomic annotation of these sequences suggests that Aiptasia is associated with a diverse viral community, comprising 116 viral taxa covering 40 families. The viral assemblage was dominated by viruses from the families Herpesviridae (12.00%), Partitiviridae (9.93%), and Picornaviridae (9.87%). Despite an overall stable viral assemblage, we found that some viral taxa exhibited significant changes in their relative abundance when Aiptasia engaged in a symbiotic relationship with Symbiodinium. Elucidation of viral taxa consistently present across all conditions revealed a core virome of 15 viral taxa from 11 viral families, encompassing many viruses previously reported as members of coral viromes. Despite the non-random selection of viral genetic material due to the nature of the sequencing data analyzed, our study provides a first insight into the viral community associated with Aiptasia. Similarities of the Aiptasia viral community with those of corals corroborate the application of Aiptasia as a model system to study coral holobionts. Further, the change in abundance of certain viral taxa across different symbiotic states suggests a role of viruses in the algal endosymbiosis, but the functional significance of this remains to be determined.}, }
@article {pmid29505062, year = {2018}, author = {Haag, KL}, title = {Holobionts and their hologenomes: Evolution with mixed modes of inheritance.}, journal = {Genetics and molecular biology}, volume = {41}, number = {1 suppl 1}, pages = {189-197}, doi = {10.1590/1678-4685-GMB-2017-0070}, pmid = {29505062}, issn = {1415-4757}, abstract = {Symbioses are ubiquitous and have played an influential role in the evolution of life on Earth. Genomic studies are now revealing a huge diversity of associations among hosts and their microbiotas, allowing us to characterize their complex ecological and evolutionary dynamics. The different transmission modes and the asynchronous cell proliferation of the numerous symbionts associated with one host generate a genomic conflict ought to be solved. Two disputing views have been used to model and predict the outcome of such conflicts. The traditional view is based on community ecology, and considers that selection at the level of individuals is sufficient to explain longstanding associations among species. A new perspective considers that the host and its associated microbiota constitute a biological entity called holobiont, and that regarding it as a higher-level unit of selection is unavoidable to understand phenotypic evolution. Novel extended phenotypes are often built through symbiotic interactions, allowing the holobiont to explore and survive in distinct environmental conditions, and may evolve in a Lamarckian fashion.}, }
@article {pmid29499735, year = {2018}, author = {Tetreau, G and Grizard, S and Patil, CD and Tran, FH and Tran Van, V and Stalinski, R and Laporte, F and Mavingui, P and Després, L and Valiente Moro, C}, title = {Bacterial microbiota of Aedes aegypti mosquito larvae is altered by intoxication with Bacillus thuringiensis israelensis.}, journal = {Parasites &amp; vectors}, volume = {11}, number = {1}, pages = {121}, doi = {10.1186/s13071-018-2741-8}, pmid = {29499735}, issn = {1756-3305}, support = {ANR-13-EBID-0007-01//Agence Nationale de la Recherche/International ; }, abstract = {BACKGROUND: Insect microbiota is a dynamic microbial community that can actively participate in defense against pathogens. Bacillus thuringiensis (Bt) is a natural entomopathogen widely used as a bioinsecticide for pest control. Although Bt's mode of action has been extensively studied, whether the presence of microbiota is mandatory for Bt to effectively kill the insect is still under debate. An association between a higher tolerance and a modified microbiota was already evidenced but a critical point remained to be solved: is the modified microbiota a cause or a consequence of a higher tolerance to Bt?<br><br>METHODS: In this study we focused on the mosquito species Aedes aegypti, as no work has been performed on Diptera on this topic to date, and on B. thuringiensis israelensis (Bti), which is used worldwide for mosquito control. To avoid using antibiotics to cure bacterial microbiota, mosquito larvae were exposed to an hourly increasing dose of Bti during 25 hours to separate the most susceptible larvae dying quickly from more tolerant individuals, with longer survival.<br><br>RESULTS: Denaturing gradient gel electrophoresis (DGGE) fingerprinting revealed that mosquito larval bacterial microbiota was strongly affected by Bti infection after only a few hours of exposure. Bacterial microbiota from the most tolerant larvae showed the lowest diversity but the highest inter-individual differences. The proportion of Bti in the host tissue was reduced in the most tolerant larvae as compared to the most susceptible ones, suggesting an active control of Bti infection by the host.<br><br>CONCLUSIONS: Here we show that a modified microbiota is associated with a higher tolerance of mosquitoes to Bti, but that it is rather a consequence of Bti infection than the cause of the higher tolerance. This study paves the way to future investigations aiming at unraveling the role of host immunity, inter-species bacterial competition and kinetics of host colonization by Bti that could be at the basis of the phenotype observed in this study.}, }
@article {pmid29492882, year = {2018}, author = {Grasis, JA}, title = {Host-Associated Bacteriophage Isolation and Preparation for Viral Metagenomics.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1746}, number = {}, pages = {1-25}, doi = {10.1007/978-1-4939-7683-6_1}, pmid = {29492882}, issn = {1940-6029}, abstract = {Prokaryotic viruses, or bacteriophages, are viruses that infect bacteria and archaea. These viruses have been known to associate with host systems for decades, yet only recently have their influence on the regulation of host-associated bacteria been appreciated. These studies have been conducted in many host systems, from the base of animal life in the Cnidarian phylum to mammals. These prokaryotic viruses are useful for regulating the number of bacteria in a host ecosystem and for regulating the strains of bacteria useful for the microbiome. These viruses are likely selected by the host to maintain bacterial populations. Viral metagenomics allows researchers to profile the communities of viruses associating with animal hosts, and importantly helps to determine the functional role these viruses play. Further, viral metagenomics show the sphere of viral involvement in gene flow and gene shuffling in an ever-changing host environment. The influence of prokaryotic viruses could, therefore, have a clear impact on host health.}, }
@article {pmid29473977, year = {2018}, author = {Ramsby, BD and Hoogenboom, MO and Whalan, S and Webster, NS}, title = {Elevated seawater temperature disrupts the microbiome of an ecologically important bioeroding sponge.}, journal = {Molecular ecology}, volume = {27}, number = {8}, pages = {2124-2137}, doi = {10.1111/mec.14544}, pmid = {29473977}, issn = {1365-294X}, abstract = {Bioeroding sponges break down calcium carbonate substratum, including coral skeleton, and their capacity for reef erosion is expected to increase in warmer and more acidic oceans. However, elevated temperature can disrupt the functionally important microbial symbionts of some sponge species, often with adverse consequences for host health. Here, we provide the first detailed description of the microbial community of the bioeroding sponge Cliona orientalis and assess how the community responds to seawater temperatures incrementally increasing from 23°C to 32°C. The microbiome, identified using 16S rRNA gene sequencing, was dominated by Alphaproteobacteria, including a single operational taxonomic unit (OTU; Rhodothalassium sp.) that represented 21% of all sequences. The &quot;core&quot; microbial community (taxa present in >80% of samples) included putative nitrogen fixers and ammonia oxidizers, suggesting that symbiotic nitrogen metabolism may be a key function of the C. orientalis holobiont. The C. orientalis microbiome was generally stable at temperatures up to 27°C; however, a community shift occurred at 29°C, including changes in the relative abundance and turnover of microbial OTUs. Notably, this microbial shift occurred at a lower temperature than the 32°C threshold that induced sponge bleaching, indicating that changes in the microbiome may play a role in the destabilization of the C. orientalis holobiont. C. orientalis failed to regain Symbiodinium or restore its baseline microbial community following bleaching, suggesting that the sponge has limited ability to recover from extreme thermal exposure, at least under aquarium conditions.}, }
@article {pmid29468040, year = {2018}, author = {Pogoreutz, C and Rädecker, N and Cárdenas, A and Gärdes, A and Wild, C and Voolstra, CR}, title = {Dominance of Endozoicomonas bacteria throughout coral bleaching and mortality suggests structural inflexibility of the Pocillopora verrucosa microbiome.}, journal = {Ecology and evolution}, volume = {8}, number = {4}, pages = {2240-2252}, doi = {10.1002/ece3.3830}, pmid = {29468040}, issn = {2045-7758}, abstract = {The importance of Symbiodinium algal endosymbionts and a diverse suite of bacteria for coral holobiont health and functioning are widely acknowledged. Yet, we know surprisingly little about microbial community dynamics and the stability of host-microbe associations under adverse environmental conditions. To gain insight into the stability of coral host-microbe associations and holobiont structure, we assessed changes in the community structure of Symbiodinium and bacteria associated with the coral Pocillopora verrucosa under excess organic nutrient conditions. Pocillopora-associated microbial communities were monitored over 14 days in two independent experiments. We assessed the effect of excess dissolved organic nitrogen (DON) and excess dissolved organic carbon (DOC). Exposure to excess nutrients rapidly affected coral health, resulting in two distinct stress phenotypes: coral bleaching under excess DOC and severe tissue sloughing (>90% tissue loss resulting in host mortality) under excess DON. These phenotypes were accompanied by structural changes in the Symbiodinium community. In contrast, the associated bacterial community remained remarkably stable and was dominated by two Endozoicomonas phylotypes, comprising on average 90% of 16S rRNA gene sequences. This dominance of Endozoicomonas even under conditions of coral bleaching and mortality suggests the bacterial community of P. verrucosa may be rather inflexible and thereby unable to respond or acclimatize to rapid changes in the environment, contrary to what was previously observed in other corals. In this light, our results suggest that coral holobionts might occupy structural landscapes ranging from a highly flexible to a rather inflexible composition with consequences for their ability to respond to environmental change.}, }
@article {pmid29463295, year = {2018}, author = {Brener-Raffalli, K and Clerissi, C and Vidal-Dupiol, J and Adjeroud, M and Bonhomme, F and Pratlong, M and Aurelle, D and Mitta, G and Toulza, E}, title = {Thermal regime and host clade, rather than geography, drive Symbiodinium and bacterial assemblages in the scleractinian coral Pocillopora damicornis sensu lato.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {39}, doi = {10.1186/s40168-018-0423-6}, pmid = {29463295}, issn = {2049-2618}, support = {ANR-12-ADAP-0016//Agence Nationale de la Recherche/ ; }, abstract = {BACKGROUND: Although the term holobiont has been popularized in corals with the advent of the hologenome theory of evolution, the underlying concepts are still a matter of debate. Indeed, the relative contribution of host and environment and especially thermal regime in shaping the microbial communities should be examined carefully to evaluate the potential role of symbionts for holobiont adaptation in the context of global changes. We used the sessile, long-lived, symbiotic and environmentally sensitive reef-building coral Pocillopora damicornis to address these issues.<br><br>RESULTS: We sampled Pocillopora damicornis colonies corresponding to two different mitochondrial lineages in different geographic areas displaying different thermal regimes: Djibouti, French Polynesia, New Caledonia, and Taiwan. The community composition of bacteria and the algal endosymbiont Symbiodinium were characterized using high-throughput sequencing of 16S rRNA gene and internal transcribed spacer, ITS2, respectively. Bacterial microbiota was very diverse with high prevalence of Endozoicomonas, Arcobacter, and Acinetobacter in all samples. While Symbiodinium sub-clade C1 was dominant in Taiwan and New Caledonia, D1 was dominant in Djibouti and French Polynesia. Moreover, we also identified a high background diversity (i.e., with proportions < 1%) of A1, C3, C15, and G Symbiodinum sub-clades. Using redundancy analyses, we found that the effect of geography was very low for both communities and that host genotypes and temperatures differently influenced Symbiodinium and bacterial microbiota. Indeed, while the constraint of host haplotype was higher than temperatures on bacterial composition, we showed for the first time a strong relationship between the composition of Symbiodinium communities and minimal sea surface temperatures.<br><br>CONCLUSION: Because Symbiodinium assemblages are more constrained by the thermal regime than bacterial communities, we propose that their contribution to adaptive capacities of the holobiont to temperature changes might be higher than the influence of bacterial microbiota. Moreover, the link between Symbiodinium community composition and minimal temperatures suggests low relative fitness of clade D at lower temperatures. This observation is particularly relevant in the context of climate change, since corals will face increasing temperatures as well as much frequent abnormal cold episodes in some areas of the world.}, }
@article {pmid29453252, year = {2018}, author = {Romano, S}, title = {Ecology and Biotechnological Potential of Bacteria Belonging to the Genus Pseudovibrio.}, journal = {Applied and environmental microbiology}, volume = {84}, number = {8}, pages = {}, doi = {10.1128/AEM.02516-17}, pmid = {29453252}, issn = {1098-5336}, abstract = {Members of the genus Pseudovibrio have been isolated worldwide from a great variety of marine sources as both free-living and host-associated bacteria. So far, the available data depict a group of alphaproteobacteria characterized by a versatile metabolism, which allows them to use a variety of substrates to meet their carbon, nitrogen, sulfur, and phosphorous requirements. Additionally, Pseudovibrio-related bacteria have been shown to proliferate under extreme oligotrophic conditions, tolerate high heavy-metal concentrations, and metabolize potentially toxic compounds. Considering this versatility, it is not surprising that they have been detected from temperate to tropical regions and are often the most abundant isolates obtained from marine invertebrates. Such an association is particularly recurrent with marine sponges and corals, animals that play a key role in benthic marine systems. The data so far available indicate that these bacteria are mainly beneficial to the host, and besides being involved in major nutrient cycles, they could provide the host with both vitamins/cofactors and protection from potential pathogens via the synthesis of antimicrobial secondary metabolites. In fact, the biosynthetic abilities of Pseudovibrio spp. have been emerging in recent years, and both genomic and analytic studies have underlined how these organisms promise novel natural products of biotechnological value.}, }
@article {pmid29441234, year = {2018}, author = {Bonthond, G and Merselis, DG and Dougan, KE and Graff, T and Todd, W and Fourqurean, JW and Rodriguez-Lanetty, M}, title = {Inter-domain microbial diversity within the coral holobiont Siderastrea siderea from two depth habitats.}, journal = {PeerJ}, volume = {6}, number = {}, pages = {e4323}, doi = {10.7717/peerj.4323}, pmid = {29441234}, issn = {2167-8359}, abstract = {Corals host diverse microbial communities that are involved in acclimatization, pathogen defense, and nutrient cycling. Surveys of coral-associated microbes have been particularly directed toward Symbiodinium and bacteria. However, a holistic understanding of the total microbiome has been hindered by a lack of analyses bridging taxonomically disparate groups. Using high-throughput amplicon sequencing, we simultaneously characterized the Symbiodinium, bacterial, and fungal communities associated with the Caribbean coral Siderastrea siderea collected from two depths (17 and 27 m) on Conch reef in the Florida Keys. S. siderea hosted an exceptionally diverse Symbiodinium community, structured differently between sampled depth habitats. While dominated at 27 m by a Symbiodinium belonging to clade C, at 17 m S. siderea primarily hosted a mixture of clade B types. Most fungal operational taxonomic units were distantly related to available reference sequences, indicating the presence of a high degree of fungal novelty within the S. siderea holobiont and a lack of knowledge on the diversity of fungi on coral reefs. Network analysis showed that co-occurrence patterns in the S. siderea holobiont were prevalent among bacteria, however, also detected between fungi and bacteria. Overall, our data show a drastic shift in the associated Symbiodinium community between depths on Conch Reef, which might indicate that alteration in this community is an important mechanism facilitating local physiological adaptation of the S. siderea holobiont. In contrast, bacterial and fungal communities were not structured differently between depth habitats.}, }
@article {pmid29435256, year = {2018}, author = {Leite, DCA and Salles, JF and Calderon, EN and van Elsas, JD and Peixoto, RS}, title = {Specific plasmid patterns and high rates of bacterial co-occurrence within the coral holobiont.}, journal = {Ecology and evolution}, volume = {8}, number = {3}, pages = {1818-1832}, doi = {10.1002/ece3.3717}, pmid = {29435256}, issn = {2045-7758}, abstract = {Despite the importance of coral microbiomes for holobiont persistence, the interactions among these are not well understood. In particular, knowledge of the co-occurrence and taxonomic importance of specific members of the microbial core, as well as patterns of specific mobile genetic elements (MGEs), is lacking. We used seawater and mucus samples collected from Mussismilia hispida colonies on two reefs located in Bahia, Brazil, to disentangle their associated bacterial communities, intertaxa correlations, and plasmid patterns. Proxies for two broad-host-range (BHR) plasmid groups, IncP-1β and PromA, were screened. Both groups were significantly (up to 252 and 100%, respectively) more abundant in coral mucus than in seawater. Notably, the PromA plasmid group was detected only in coral mucus samples. The core bacteriome of M. hispida mucus was composed primarily of members of the Proteobacteria, followed by those of Firmicutes. Significant host specificity and co-occurrences among different groups of the dominant phyla (e.g., Bacillaceae and Pseudoalteromonadaceae and the genera Pseudomonas, Bacillus, and Vibrio) were detected. These relationships were observed for both the most abundant phyla and the bacteriome core, in which most of the operational taxonomic units showed intertaxa correlations. The observed evidence of host-specific bacteriome and co-occurrence (and potential symbioses or niche space co-dominance) among the most dominant members indicates a taxonomic selection of members of the stable bacterial community. In parallel, host-specific plasmid patterns could also be, independently, related to the assembly of members of the coral microbiome.}, }
@article {pmid29433554, year = {2018}, author = {Cregger, MA and Veach, AM and Yang, ZK and Crouch, MJ and Vilgalys, R and Tuskan, GA and Schadt, CW}, title = {The Populus holobiont: dissecting the effects of plant niches and genotype on the microbiome.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {31}, doi = {10.1186/s40168-018-0413-8}, pmid = {29433554}, issn = {2049-2618}, abstract = {BACKGROUND: Microorganisms serve important functions within numerous eukaryotic host organisms. An understanding of the variation in the plant niche-level microbiome, from rhizosphere soils to plant canopies, is imperative to gain a better understanding of how both the structural and functional processes of microbiomes impact the health of the overall plant holobiome. Using Populus trees as a model ecosystem, we characterized the archaeal/bacterial and fungal microbiome across 30 different tissue-level niches within replicated Populus deltoides and hybrid Populus trichocarpa × deltoides individuals using 16S and ITS2 rRNA gene analyses.<br><br>RESULTS: Our analyses indicate that archaeal/bacterial and fungal microbiomes varied primarily across broader plant habitat classes (leaves, stems, roots, soils) regardless of plant genotype, except for fungal communities within leaf niches, which were greatly impacted by the host genotype. Differences between tree genotypes are evident in the elevated presence of two potential fungal pathogens, Marssonina brunnea and Septoria sp., on hybrid P. trichocarpa × deltoides trees which may in turn be contributing to divergence in overall microbiome composition. Archaeal/bacterial diversity increased from leaves, to stem, to root, and to soil habitats, whereas fungal diversity was the greatest in stems and soils.<br><br>CONCLUSIONS: This study provides a holistic understanding of microbiome structure within a bioenergy relevant plant host, one of the most complete niche-level analyses of any plant. As such, it constitutes a detailed atlas or map for further hypothesis testing on the significance of individual microbial taxa within specific niches and habitats of Populus and a baseline for comparisons to other plant species.}, }
@article {pmid29430857, year = {2018}, author = {Voss, JD and Goodson, MS and Leon, JC}, title = {Phenotype diffusion and one health: A proposed framework for investigating the plurality of obesity epidemics across many species.}, journal = {Zoonoses and public health}, volume = {65}, number = {3}, pages = {279-290}, doi = {10.1111/zph.12445}, pmid = {29430857}, issn = {1863-2378}, abstract = {We propose the idea of &quot;phenotype diffusion,&quot; which is a rapid convergence of an observed trait in some human and animal populations. The words phenotype and diffusion both imply observations independent of mechanism as phenotypes are observed traits with multiple possible genetic mechanisms and diffusion is an observed state of being widely distributed. Recognizing shared changes in phenotype in multiple species does not by itself reveal a particular mechanism such as a shared exposure, shared adaptive need, particular stochastic process or a transmission pathway. Instead, identifying phenotype diffusion suggests the mechanism should be explored to help illuminate the ways human and animal health are connected and new opportunities for optimizing these links. Using the plurality of obesity epidemics across multiple species as a prototype for shared changes in phenotype, the goal of this review was to explore eco-evolutionary theories that could inform further investigation. First, evolutionary changes described by hologenome evolution, pawnobe evolution, transposable element (TE) thrust and the drifty gene hypothesis will be discussed within the context of the selection asymmetries among human and animal populations. Secondly, the ecology of common source exposures (bovine milk, xenohormesis and &quot;obesogens&quot;), niche evolution and the hygiene hypothesis will be summarized. Finally, we synthesize these considerations. For example, many agricultural breeds have been aggressively selected for weight gain, microbiota (e.g., adenovirus 36, toxoplasmosis) associated with (or infecting) these breeds cause experimental weight gain in other animals, and these same microbes are associated with human obesity. We propose applications of phenotype diffusion could include zoonotic biosurveillance, biocontainment, antibiotic stewardship and environmental priorities. The One Health field is focused on the connections between the health of humans, animals and the environment, and so identification of phenotype diffusion is highly relevant for practitioners (public health officials, physicians and veterinarians) in this field.}, }
@article {pmid29423641, year = {2018}, author = {Feng, G and Sun, W and Zhang, F and Orlić, S and Li, Z}, title = {Functional Transcripts Indicate Phylogenetically Diverse Active Ammonia-Scavenging Microbiota in Sympatric Sponges.}, journal = {Marine biotechnology (New York, N.Y.)}, volume = {20}, number = {2}, pages = {131-143}, doi = {10.1007/s10126-018-9797-5}, pmid = {29423641}, issn = {1436-2236}, abstract = {Symbiotic ammonia scavengers contribute to effective removal of ammonia in sponges. However, the phylogenetic diversity and in situ activity of ammonia-scavenging microbiota between different sponge species are poorly addressed. Here, transcribed ammonia monooxygenase genes (amoA), hydrazine synthase genes (hzsA), and glutamine synthetase genes (glnA) were analyzed to reveal the active ammonia-scavenging microbiota in the sympatric sponges Theonella swinhoei, Plakortis simplex, and Phakellia fusca, and seawater. Archaeal amoA and bacterial glnA transcripts rather than bacterial amoA, hzsA, and archaeal glnA transcripts were detected in the investigated sponges and seawater. The transcribed amoA genes were ascribed to two Thaumarchaeota ecotypes, while the transcribed glnA genes were interspersed among the lineages of Cyanobacteria, Tectomicrobia, Poribacteria, Alpha-, Beta-, Gamma-, and Epsilonproteobacteria. In addition, transcribed abundances of archaeal amoA and bacterial glnA genes in these sponges have been quantified, showing significant variation among the investigated sponges and seawater. The transcriptome-based qualitative and quantitative analyses clarified the different phylogenetic diversity and transcription expression of functional genes related to microbially mediated ammonia scavenging in different sympatric sponges, contributing to the understanding of in situ active ecological functions of sponge microbial symbionts in holobiont nitrogen cycling.}, }
@article {pmid29410656, year = {2018}, author = {Rubio-Portillo, E and Kersting, DK and Linares, C and Ramos-Esplá, AA and Antón, J}, title = {Biogeographic Differences in the Microbiome and Pathobiome of the Coral Cladocora caespitosa in the Western Mediterranean Sea.}, journal = {Frontiers in microbiology}, volume = {9}, number = {}, pages = {22}, doi = {10.3389/fmicb.2018.00022}, pmid = {29410656}, issn = {1664-302X}, abstract = {The endemic Mediterranean zooxanthellate scleractinian reef-builder Cladocora caespitosa is among the organisms most affected by warming-related mass mortality events in the Mediterranean Sea. Corals are known to contain a diverse microbiota that plays a key role in their physiology and health. Here we report the first study that examines the microbiome and pathobiome associated with C. caespitosa in three different Mediterranean locations (i.e., Genova, Columbretes Islands, and Tabarca Island). The microbial communities associated with this species showed biogeographical differences, but shared a common core microbiome that probably plays a key role in the coral holobiont. The putatively pathogenic microbial assemblage (i.e., pathobiome) of C. caespitosa also seemed to depend on geographic location and the human footprint. In locations near the coast and with higher human influence, the pathobiome was entirely constituted by Vibrio species, including the well-known coral pathogens Vibrio coralliilyticus and V. mediterranei. However, in the Columbretes Islands, located off the coast and the most pristine of the analyzed locations, no changes among microbial communities associated to healthy and necrosed samples were detected. Hence, our results provide new insights into the microbiome of the temperate corals and its role in coral health status, highlighting its dependence on the local environmental conditions and the human footprint.}, }
@article {pmid29403516, year = {2018}, author = {Saminathan, T and García, M and Ghimire, B and Lopez, C and Bodunrin, A and Nimmakayala, P and Abburi, VL and Levi, A and Balagurusamy, N and Reddy, UK}, title = {Metagenomic and Metatranscriptomic Analyses of Diverse Watermelon Cultivars Reveal the Role of Fruit Associated Microbiome in Carbohydrate Metabolism and Ripening of Mature Fruits.}, journal = {Frontiers in plant science}, volume = {9}, number = {}, pages = {4}, doi = {10.3389/fpls.2018.00004}, pmid = {29403516}, issn = {1664-462X}, abstract = {The plant microbiome is a key determinant of plant health and productivity, and changes in the plant microbiome can alter the tolerance to biotic and abiotic stresses and the quality of end produce. Little is known about the microbial diversity and its effect on carbohydrate metabolism in ripe fruits. In this study, we aimed to understand the diversity and function of microorganisms in relation to carbohydrate metabolism of ripe watermelon fruits. We used 16S metagenomics and RNAseq metatranscriptomics for analysis of red (PI459074, Congo, and SDRose) and yellow fruit-flesh cultivars (PI227202, PI435990, and JBush) of geographically and metabolically diverse watermelon cultivars. Metagenomics data showed that Proteobacteria were abundant in SDRose and PI227202, whereas Cyanobacteria were most abundant in Congo and PI4559074. In the case of metatranscriptome data, Proteobacteria was the most abundant in all cultivars. High expression of genes linked to infectious diseases and the expression of peptidoglycan hydrolases associated to pathogenicity of eukaryotic hosts was observed in SDRose, which could have resulted in low microbial diversity in this cultivar. The presence of GH28, associated with polygalacturonase activity in JBush and SDRose could be related to cell wall modifications including de-esterification and depolymerization, and consequent loss of galacturonic acid and neutral sugars. Moreover, based on the KEGG annotation of the expressed genes, nine α-galactosidase genes involved in key processes of galactosyl oligosaccharide metabolism, such as raffinose family were identified and galactose metabolism pathway was reconstructed. Results of this study underline the links between the host and fruit-associated microbiome in carbohydrate metabolism of the ripe fruits. The cultivar difference in watermelon reflects the quantum and diversity of the microbiome, which would benefit watermelon and other plant breeders aiming at the holobiont concept to incorporate associated microbiomes in breeding programs.}, }
@article {pmid29396559, year = {2018}, author = {Massé, A and Domart-Coulon, I and Golubic, S and Duché, D and Tribollet, A}, title = {Early skeletal colonization of the coral holobiont by the microboring Ulvophyceae Ostreobium sp.}, journal = {Scientific reports}, volume = {8}, number = {1}, pages = {2293}, doi = {10.1038/s41598-018-20196-5}, pmid = {29396559}, issn = {2045-2322}, abstract = {Ostreobium sp. (Bryopsidales, Ulvophyceae) is a major microboring alga involved in tropical reef dissolution, with a proposed symbiotic lifestyle in living corals. However, its diversity and colonization dynamics in host's early life stages remained unknown. Here, we mapped microborer distribution and abundance in skeletons of the branching coral Pocillopora damicornis from the onset of calcification in primary polyps (7 days) to budding juvenile colonies (1 and 3 months) growing on carbonate and non-carbonate substrates pre-colonized by natural biofilms, and compared them to adult colonies (in aquarium settings). Primary polyps were surprisingly already colonized by microboring filaments and their level of invasion depended on the nature of settlement substrate and the extent of its pre-colonization by microborers. Growth of early coral recruits was unaffected even when microborers were in close vicinity to the polyp tissue. In addition to morphotype observations, chloroplast-encoded rbcL gene sequence analyses revealed nine new Ostreobium clades (OTU99%) in Pocillopora coral. Recruits and adults shared one dominant rbcL clade, undetected in larvae, but also present in aquarium seawater, carbonate and non-carbonate settlement substrates, and in corals from reef settings. Our results show a substratum-dependent colonization by Ostreobium clades, and indicate horizontal transmission of Ostreobium-coral associations.}, }
@article {pmid29395346, year = {2018}, author = {Limborg, MT and Alberdi, A and Kodama, M and Roggenbuck, M and Kristiansen, K and Gilbert, MTP}, title = {Applied Hologenomics: Feasibility and Potential in Aquaculture.}, journal = {Trends in biotechnology}, volume = {36}, number = {3}, pages = {252-264}, doi = {10.1016/j.tibtech.2017.12.006}, pmid = {29395346}, issn = {1879-3096}, abstract = {Aquaculture will play an essential role in feeding a growing human population, but several biological challenges impede sustainable growth of production. Emerging evidence across all areas of life has revealed the importance of the intimate biological interactions between animals and their associated gut microbiota. Based on challenges in aquaculture, we leverage current knowledge in molecular biology and host microbiota interactions to propose an applied holo-omic framework that integrates molecular data including genomes, transcriptomes, epigenomes, proteomes, and metabolomes for analyzing fish and their gut microbiota as interconnected and coregulated systems. With an eye towards aquaculture, we discuss the feasibility and potential of our holo-omic framework to improve growth, health, and sustainability in any area of food production, including livestock and agriculture.}, }
@article {pmid29386628, year = {2018}, author = {Achlatis, M and Pernice, M and Green, K and Guagliardo, P and Kilburn, MR and Hoegh-Guldberg, O and Dove, S}, title = {Single-cell measurement of ammonium and bicarbonate uptake within a photosymbiotic bioeroding sponge.}, journal = {The ISME journal}, volume = {12}, number = {5}, pages = {1308-1318}, doi = {10.1038/s41396-017-0044-2}, pmid = {29386628}, issn = {1751-7370}, abstract = {Some of the most aggressive coral-excavating sponges host intracellular dinoflagellates from the genus Symbiodinium, which are hypothesized to provide the sponges with autotrophic energy that powers bioerosion. Investigations of the contribution of Symbiodinium to host metabolism and particularly inorganic nutrient recycling are complicated, however, by the presence of alternative prokaryotic candidates for this role. Here, novel methods are used to study nutrient assimilation and transfer within and between the outer-layer cells of the Indopacific bioeroding sponge Cliona orientalis. Combining stable isotope labelling, transmission electron microscopy (TEM) and nanoscale secondary ion mass spectrometry (NanoSIMS), we visualize and measure metabolic activity at the individual cell level, tracking the fate of 15N-ammonium and 13C-bicarbonate within the intact holobiont. We found strong uptake of both inorganic sources (especially 13C-bicarbonate) by Symbiodinium cells. Labelled organic nutrients were translocated from Symbiodinium to the Symbiodinium-hosting sponge cells within 6 h, and occasionally to other sponge cells within 3 days. By contrast, prokaryotic symbionts were not observed to participate in inorganic nutrient assimilation in the outer layers of the sponge. Our findings strongly support the metabolic interaction between the sponge and dinoflagellates, shedding light on the ecological advantages and adaptive capacity of photosymbiotic bioeroding sponges in oligotrophic marine habitats.}, }
@article {pmid29382945, year = {2018}, author = {Frischkorn, KR and Haley, ST and Dyhrman, ST}, title = {Coordinated gene expression between Trichodesmium and its microbiome over day-night cycles in the North Pacific Subtropical Gyre.}, journal = {The ISME journal}, volume = {12}, number = {4}, pages = {997-1007}, doi = {10.1038/s41396-017-0041-5}, pmid = {29382945}, issn = {1751-7370}, abstract = {Trichodesmium is a widespread, N2 fixing marine cyanobacterium that drives inputs of newly fixed nitrogen and carbon into the oligotrophic ecosystems where it occurs. Colonies of Trichodesmium ubiquitously occur with heterotrophic bacteria that make up a diverse microbiome, and interactions within this Trichodesmium holobiont could influence the fate of fixed carbon and nitrogen. Metatranscriptome sequencing was performed on Trichodesmium colonies collected during high-frequency Lagrangian sampling in the North Pacific Subtropical Gyre (NPSG) to identify possible interactions between the Trichodesmium host and microbiome over day-night cycles. Here we show significantly coordinated patterns of gene expression between host and microbiome, many of which had significant day-night periodicity. The functions of the co-expressed genes suggested a suite of interactions within the holobiont linked to key resources including nitrogen, carbon, and iron. Evidence of microbiome reliance on Trichodesmium-derived vitamin B12 was also detected in co-expression patterns, highlighting a dependency that could shape holobiont community structure. Collectively, these patterns of expression suggest that biotic interactions could influence colony cycling of resources like nitrogen and vitamin B12, and decouple activities, like N2 fixation, from typical abiotic drivers of Trichodesmium physiological ecology.}, }
@article {pmid29379177, year = {2018}, author = {Baker, DM and Freeman, CJ and Wong, JCY and Fogel, ML and Knowlton, N}, title = {Climate change promotes parasitism in a coral symbiosis.}, journal = {The ISME journal}, volume = {12}, number = {3}, pages = {921-930}, doi = {10.1038/s41396-018-0046-8}, pmid = {29379177}, issn = {1751-7370}, abstract = {Coastal oceans are increasingly eutrophic, warm and acidic through the addition of anthropogenic nitrogen and carbon, respectively. Among the most sensitive taxa to these changes are scleractinian corals, which engineer the most biodiverse ecosystems on Earth. Corals' sensitivity is a consequence of their evolutionary investment in symbiosis with the dinoflagellate alga, Symbiodinium. Together, the coral holobiont has dominated oligotrophic tropical marine habitats. However, warming destabilizes this association and reduces coral fitness. It has been theorized that, when reefs become warm and eutrophic, mutualistic Symbiodinium sequester more resources for their own growth, thus parasitizing their hosts of nutrition. Here, we tested the hypothesis that sub-bleaching temperature and excess nitrogen promotes symbiont parasitism by measuring respiration (costs) and the assimilation and translocation of both carbon (energy) and nitrogen (growth; both benefits) within Orbicella faveolata hosting one of two Symbiodinium phylotypes using a dual stable isotope tracer incubation at ambient (26 °C) and sub-bleaching (31 °C) temperatures under elevated nitrate. Warming to 31 °C reduced holobiont net primary productivity (NPP) by 60% due to increased respiration which decreased host %carbon by 15% with no apparent cost to the symbiont. Concurrently, Symbiodinium carbon and nitrogen assimilation increased by 14 and 32%, respectively while increasing their mitotic index by 15%, whereas hosts did not gain a proportional increase in translocated photosynthates. We conclude that the disparity in benefits and costs to both partners is evidence of symbiont parasitism in the coral symbiosis and has major implications for the resilience of coral reefs under threat of global change.}, }
@article {pmid29378627, year = {2018}, author = {Broberg, M and Doonan, J and Mundt, F and Denman, S and McDonald, JE}, title = {Integrated multi-omic analysis of host-microbiota interactions in acute oak decline.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {21}, doi = {10.1186/s40168-018-0408-5}, pmid = {29378627}, issn = {2049-2618}, support = {TH0108//Department for Environment, Food and Rural Affairs/ ; }, abstract = {BACKGROUND: Britain's native oak species are currently under threat from acute oak decline (AOD), a decline-disease where stem bleeds overlying necrotic lesions in the inner bark and larval galleries of the bark-boring beetle, Agrilus biguttatus, represent the primary symptoms. It is known that complex interactions between the plant host and its microbiome, i.e. the holobiont, significantly influence the health status of the plant. In AOD, necrotic lesions are caused by a microbiome shift to a pathobiome consisting predominantly of Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana and potentially other bacteria. However, the specific mechanistic processes of the microbiota causing tissue necrosis, and the host response, have not been established and represent a barrier to understanding and managing this decline.<br><br>RESULTS: We profiled the metagenome, metatranscriptome and metaproteome of inner bark tissue from AOD symptomatic and non-symptomatic trees to characterise microbiota-host interactions. Active bacterial virulence factors such as plant cell wall-degrading enzymes, reactive oxygen species defence and flagella in AOD lesions, along with host defence responses including reactive oxygen species, cell wall modification and defence regulators were identified. B. goodwinii dominated the lesion microbiome, with significant expression of virulence factors such as the phytopathogen effector avrE. A smaller proportion of microbiome activity was attributed to G. quercinecans and R. victoriana. In addition, we describe for the first time the potential role of two previously uncharacterised Gram-positive bacteria predicted from metagenomic binning and identified as active in the AOD lesion metatranscriptome and metaproteome, implicating them in lesion formation.<br><br>CONCLUSIONS: This multi-omic study provides novel functional insights into microbiota-host interactions in AOD, a complex arboreal decline disease where polymicrobial-host interactions result in lesion formation on tree stems. We present the first descriptions of holobiont function in oak health and disease, specifically, the relative lesion activity of B. goodwinii, G. quercinecans, Rahnella victoriana and other bacteria. Thus, the research presented here provides evidence of some of the mechanisms used by members of the lesion microbiome and a template for future multi-omic research into holobiont characterisation, plant polymicrobial diseases and pathogen defence in trees.}, }
@article {pmid29374490, year = {2018}, author = {Liu, J and Abdelfattah, A and Norelli, J and Burchard, E and Schena, L and Droby, S and Wisniewski, M}, title = {Apple endophytic microbiota of different rootstock/scion combinations suggests a genotype-specific influence.}, journal = {Microbiome}, volume = {6}, number = {1}, pages = {18}, doi = {10.1186/s40168-018-0403-x}, pmid = {29374490}, issn = {2049-2618}, support = {2017YFD0201100//National Key Research and Development Program of China/ ; IS 2513-16//U.S. - Israel Binational Agricultural Research and Development Fund/ ; R2016LX01//Foundation for High-level Talents of Chongqing University of Arts and Sciences/ ; }, abstract = {BACKGROUND: High-throughput amplicon sequencing spanning conserved portions of microbial genomes (16s rRNA and ITS) was used in the present study to describe the endophytic microbiota associated with three apple varieties, &quot;Royal Gala,&quot; &quot;Golden Delicious,&quot; and &quot;Honey Crisp,&quot; and two rootstocks, M.9 and M.M.111. The objectives were to (1) determine if the microbiota differs in different rootstocks and apple varieties and (2) determine if specific rootstock-scion combinations influence the microbiota composition of either component.<br><br>RESULTS: Results indicated that Ascomycota (47.8%), Zygomycota (31.1%), and Basidiomycota (11.6%) were the dominant fungal phyla across all samples. The majority of bacterial sequences were assigned to Proteobacteria (58.4%), Firmicutes (23.8%), Actinobacteria (7.7%), Bacteroidetes (2%), and Fusobacteria (0.4%). Rootstocks appeared to influence the microbiota of associated grafted scion, but the effect was not statistically significant. Pedigree also had an impact on the composition of the endophytic microbiota, where closely-related cultivars had a microbial community that was more similar to each other than it was to a scion cultivar that was more distantly-related by pedigree. The more vigorous rootstock (M.M.111) was observed to possess a greater number of growth-promoting bacterial taxa, relative to the dwarfing rootstock (M.9).<br><br>CONCLUSIONS: The mechanism by which an apple genotype, either rootstock or scion, has a determinant effect on the composition of a microbial community is not known. The similarity of the microbiota in samples with a similar pedigree suggests the possibility of some level of co-evolution or selection as proposed by the &quot;holobiont&quot; concept in which metaorganisms have co-evolved. Clearly, however, the present information is only suggestive, and a more comprehensive analysis is needed.}, }
@article {pmid29367878, year = {2018}, author = {Marzinelli, EM and Qiu, Z and Dafforn, KA and Johnston, EL and Steinberg, PD and Mayer-Pinto, M}, title = {Coastal urbanisation affects microbial communities on a dominant marine holobiont.}, journal = {NPJ biofilms and microbiomes}, volume = {4}, number = {}, pages = {1}, doi = {10.1038/s41522-017-0044-z}, pmid = {29367878}, issn = {2055-5008}, abstract = {Host-associated microbial communities play a fundamental role in the life of eukaryotic hosts. It is increasingly argued that hosts and their microbiota must be studied together as 'holobionts' to better understand the effects of environmental stressors on host functioning. Disruptions of host-microbiota interactions by environmental stressors can negatively affect host performance and survival. Substantial ecological impacts are likely when the affected hosts are habitat-forming species (e.g., trees, kelps) that underpin local biodiversity. In marine systems, coastal urbanisation via the addition of artificial structures is a major source of stress to habitat formers, but its effect on their associated microbial communities is unknown. We characterised kelp-associated microbial communities in two of the most common and abundant artificial structures in Sydney Harbour-pier-pilings and seawalls-and in neighbouring natural rocky reefs. The kelp Ecklonia radiata is the dominant habitat-forming species along 8000 km of the temperate Australian coast. Kelp-associated microbial communities on pilings differed significantly from those on seawalls and natural rocky reefs, possibly due to differences in abiotic (e.g., shade) and biotic (e.g., grazing) factors between habitats. Many bacteria that were more abundant on kelp on pilings belonged to taxa often associated with macroalgal diseases, including tissue bleaching in Ecklonia. There were, however, no differences in kelp photosynthetic capacity between habitats. The observed differences in microbial communities may have negative effects on the host by promoting fouling by macroorganisms or by causing and spreading disease over time. This study demonstrates that urbanisation can alter the microbiota of key habitat-forming species with potential ecological consequences.}, }
@article {pmid29366516, year = {2017}, author = {Sandoval-Motta, S and Aldana, M and Frank, A}, title = {Evolving Ecosystems: Inheritance and Selection in the Light of the Microbiome.}, journal = {Archives of medical research}, volume = {48}, number = {8}, pages = {780-789}, doi = {10.1016/j.arcmed.2018.01.002}, pmid = {29366516}, issn = {1873-5487}, abstract = {The importance of microorganisms in human biology is undeniable. The amount of research that supports that microbes have a fundamental role in animal and plant physiology is substantial and increasing every year. Even though we are only beginning to comprehend the broadness and complexity of microbial communities, evolutionary theories need to be recast in the light of such discoveries to fully understand and incorporate the role of microbes in our evolution. Fundamental evolutionary concepts such as diversity, heredity, selection, speciation, etc., which constitute the modern synthesis, are now being challenged, or at least expanded, by the emerging notion of the holobiont, which defines the genetic and metabolic networks of the host and its microbes as a single evolutionary unit. Several concepts originally developed to study ecosystems, can be used to understand the physiology and evolution of such complex systems that constitute &quot;individuals.&quot; In this review, we discuss these ecological concepts and also provide examples that range from squids, insects and koalas to other mammals and humans, suggesting that microorganisms have a fundamental role not only in physiology but also in evolution. Current evolutionary theories need to take into account the dynamics and interconnectedness of the host-microbiome network, as animals and plants not only owe their symbiogenetic origin to microbes, but also share a long evolutionary history together.}, }
@article {pmid29334418, year = {2018}, author = {van de Water, JAJM and Chaib De Mares, M and Dixon, GB and Raina, JB and Willis, BL and Bourne, DG and van Oppen, MJH}, title = {Antimicrobial and stress responses to increased temperature and bacterial pathogen challenge in the holobiont of a reef-building coral.}, journal = {Molecular ecology}, volume = {27}, number = {4}, pages = {1065-1080}, doi = {10.1111/mec.14489}, pmid = {29334418}, issn = {1365-294X}, abstract = {Global increases in coral disease prevalence have been linked to ocean warming through changes in coral-associated bacterial communities, pathogen virulence and immune system function. However, the interactive effects of temperature and pathogens on the coral holobiont are poorly understood. Here, we assessed three compartments of the holobiont (host, Symbiodinium and bacterial community) of the coral Montipora aequituberculata challenged with the pathogen Vibrio coralliilyticus and the commensal bacterium Oceanospirillales sp. under ambient (27°C) and elevated (29.5 and 32°C) seawater temperatures. Few visual signs of bleaching and disease development were apparent in any of the treatments, but responses were detected in the holobiont compartments. V. coralliilyticus acted synergistically and negatively impacted the photochemical efficiency of Symbiodinium at 32°C, while Oceanospirillales had no significant effect on photosynthetic efficiency. The coral, however, exhibited a minor response to the bacterial challenges, with the response towards V. coralliilyticus being significantly more pronounced, and involving the prophenoloxidase-activating system and multiple immune system-related genes. Elevated seawater temperatures did not induce shifts in the coral-associated bacterial community, but caused significant gene expression modulation in both Symbiodinium and the coral host. While Symbiodinium exhibited an antiviral response and upregulated stress response genes, M. aequituberculata showed regulation of genes involved in stress and innate immune response processes, including immune and cytokine receptor signalling, the complement system, immune cell activation and phagocytosis, as well as molecular chaperones. These observations show that M. aequituberculata is capable of maintaining a stable bacterial community under elevated seawater temperatures and thereby contributes to preventing disease development.}, }
@article {pmid29324042, year = {2018}, author = {Bartholomay, LC and Michel, K}, title = {Mosquito Immunobiology: The Intersection of Vector Health and Vector Competence.}, journal = {Annual review of entomology}, volume = {63}, number = {}, pages = {145-167}, doi = {10.1146/annurev-ento-010715-023530}, pmid = {29324042}, issn = {1545-4487}, abstract = {As holometabolous insects that occupy distinct aquatic and terrestrial environments in larval and adult stages and utilize hematophagy for nutrient acquisition, mosquitoes are subjected to a wide variety of symbiotic interactions. Indeed, mosquitoes play host to endosymbiotic, entomopathogenic, and mosquito-borne organisms, including protozoa, viruses, bacteria, fungi, fungal-like organisms, and metazoans, all of which trigger and shape innate infection-response capacity. Depending on the infection or interaction, the mosquito may employ, for example, cellular and humoral immune effectors for septic infections in the hemocoel, humoral infection responses in the midgut lumen, and RNA interference and programmed cell death for intracellular pathogens. These responses often function in concert, regardless of the infection type, and provide a robust front to combat infection. Mosquito-borne pathogens and entomopathogens overcome these immune responses, employing avoidance or suppression strategies. Burgeoning methodologies are capitalizing on this concerted deployment of immune responses to control mosquito-borne disease.}, }
@article {pmid29312241, year = {2017}, author = {Florez, JZ and Camus, C and Hengst, MB and Buschmann, AH}, title = {A Functional Perspective Analysis of Macroalgae and Epiphytic Bacterial Community Interaction.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2561}, doi = {10.3389/fmicb.2017.02561}, pmid = {29312241}, issn = {1664-302X}, abstract = {Macroalgae are photosynthetic, multicellular, sessile eukaryotic organisms that offer diverse habitats for the colonization of epiphytic bacteria, therefore establishing biological interactions of diverse complexity. This review focusses on the interactions between macroalgae and their Epiphytic Bacterial Community (EBC); the main aims are to ascertain whether (1) the epiphytic bacterial groups differ at the phylum and genus levels of the macroalgae; (2) the methodologies used so far to study these microorganisms are related in any way to eventual variations of the EBCs on macroalgae; and (3) the EBC of macroalgae has a functional means rather a simple taxonomic grouping. Results showed firstly the taxonomic grouping of macroalgae does not explain the composition and structure of the EBCs. Secondly, the methodology used is important for describing EBCs; and thirdly, multiple bacteria can have the same function and thus to describe the functionality of EBCs it is important to recognize host-specific and generalist bacteria. We recommend the incorporation of a complementary approach between the taxonomic composition and the functional composition analyzes of EBCs, as well as the use of methodological tools that allow analysis of interactions between the EBCs and their hosts, based on the &quot;holobiont&quot; concept.}, }
@article {pmid29312170, year = {2017}, author = {KleinJan, H and Jeanthon, C and Boyen, C and Dittami, SM}, title = {Exploring the Cultivable Ectocarpus Microbiome.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {2456}, doi = {10.3389/fmicb.2017.02456}, pmid = {29312170}, issn = {1664-302X}, abstract = {Coastal areas form the major habitat of brown macroalgae, photosynthetic multicellular eukaryotes that have great ecological value and industrial potential. Macroalgal growth, development, and physiology are influenced by the microbial community they accommodate. Studying the algal microbiome should thus increase our fundamental understanding of algal biology and may help to improve culturing efforts. Currently, a freshwater strain of the brown macroalga Ectocarpus subulatus is being developed as a model organism for brown macroalgal physiology and algal microbiome studies. It can grow in high and low salinities depending on which microbes it hosts. However, the molecular mechanisms involved in this process are still unclear. Cultivation of Ectocarpus-associated bacteria is the first step toward the development of a model system for in vitro functional studies of brown macroalgal-bacterial interactions during abiotic stress. The main aim of the present study is thus to provide an extensive collection of cultivable E. subulatus-associated bacteria. To meet the variety of metabolic demands of Ectocarpus-associated bacteria, several isolation techniques were applied, i.e., direct plating and dilution-to-extinction cultivation techniques, each with chemically defined and undefined bacterial growth media. Algal tissue and algal growth media were directly used as inoculum, or they were pretreated with antibiotics, by filtration, or by digestion of algal cell walls. In total, 388 isolates were identified falling into 33 genera (46 distinct strains), of which Halomonas (Gammaproteobacteria), Bosea (Alphaproteobacteria), and Limnobacter (Betaproteobacteria) were the most abundant. Comparisons with 16S rRNA gene metabarcoding data showed that culturability in this study was remarkably high (∼50%), although several cultivable strains were not detected or only present in extremely low abundance in the libraries. These undetected bacteria could be considered as part of the rare biosphere and they may form the basis for the temporal changes in the Ectocarpus microbiome.}, }
@article {pmid29308251, year = {2017}, author = {Sangsawang, L and Casareto, BE and Ohba, H and Vu, HM and Meekaew, A and Suzuki, T and Yeemin, T and Suzuki, Y}, title = {13C and 15N assimilation and organic matter translocation by the endolithic community in the massive coral Porites lutea.}, journal = {Royal Society open science}, volume = {4}, number = {12}, pages = {171201}, doi = {10.1098/rsos.171201}, pmid = {29308251}, issn = {2054-5703}, abstract = {Corals evolved by establishing symbiotic relationships with various microorganisms (the zooxanthellae, filamentous algae, cyanobacteria, bacteria, archaea, fungi and viruses), forming the 'coral holobiont'. Among them, the endolithic community is the least studied. Its main function was considered to be translocation of photo-assimilates to the coral host, particularly during bleaching. Here, we hypothesize that (i) endolithic algae may show similar primary production rates in healthy or bleached corals by changing their pigment ratios, and therefore that similar production and translocation of organic matter may occur at both conditions and (ii) diazotrophs are components of the endolithic community; therefore, N2 fixation and translocation of organic nitrogen may occur. We tested these hypotheses in incubation of Porites lutea with 13C and 15N tracers to measure primary production and N2 fixation in coral tissues and endoliths. Assimilation of the 13C atom (%) was observed in healthy and bleached corals when the tracer was injected in the endolithic band, showing translocation in both conditions. N2 fixation was found in coral tissues and endolithic communities with translocation of organic nitrogen. Thus, the endolithic community plays an important role in supporting the C and N metabolism of the holobiont, which may be crucial under changing environmental conditions.}, }
@article {pmid29271225, year = {2018}, author = {Sebastián Domingo, JJ and Sánchez Sánchez, C}, title = {From the intestinal flora to the microbiome.}, journal = {Revista espanola de enfermedades digestivas : organo oficial de la Sociedad Espanola de Patologia Digestiva}, volume = {110}, number = {1}, pages = {51-56}, doi = {10.17235/reed.2017.4947/2017}, pmid = {29271225}, issn = {1130-0108}, abstract = {In this article, the history of the microbiota is reviewed and the related concepts of the microbiota, microbiome, metagenome, pathobiont, dysbiosis, holobiont, phylotype and enterotype are defined. The most precise and current knowledge about the microbiota is presented and the metabolic, nutritional and immunomodulatory functions are reviewed. Some gastrointestinal diseases whose pathogenesis is associated with the intestinal microbiota, including inflammatory bowel disease, irritable bowel syndrome and celiac disease, among others, are briefly discussed. Finally, some prominent and promising data with regard to the fecal microbiota transplantation in certain digestive illness are discussed.}, }
@article {pmid29266341, year = {2018}, author = {Elgart, M and Soen, Y}, title = {Microbiome-Germline Interactions and Their Transgenerational Implications.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {40}, number = {4}, pages = {e1700018}, doi = {10.1002/bies.201700018}, pmid = {29266341}, issn = {1521-1878}, abstract = {It is becoming increasingly clear that most, if not all, animals and plants are associated with a diverse array of resident gut microbiota. This symbiosis is regulated by host-microbiome interactions which influence the development, homeostasis, adaptation and evolution of the host. Recent evidence indicated that these interactions can also affect the host germline and have a potential of supporting transgenerational effects, including inheritance of acquired characteristics. Taken together, the influence of gut bacteria on the host soma and germline could potentially give rise to emergent phenotypes, which may be partially inherited by three distinguishable modes of transgenerational influence of gut bacteria: 1) &quot;soma-to-soma&quot; 2) &quot;soma-to-germline&quot; and 3) &quot;soma-germline-soma&quot;. Here, we discuss these possibilities in light of evidence supporting bacterial-mediated modes of transgenerational inheritance.}, }
@article {pmid29245010, year = {2017}, author = {Kundu, P and Blacher, E and Elinav, E and Pettersson, S}, title = {Our Gut Microbiome: The Evolving Inner Self.}, journal = {Cell}, volume = {171}, number = {7}, pages = {1481-1493}, doi = {10.1016/j.cell.2017.11.024}, pmid = {29245010}, issn = {1097-4172}, mesh = {Aging ; Animals ; Bacteria/classification/*growth &amp; development/metabolism ; Biological Evolution ; *Gastrointestinal Microbiome ; Humans ; Infant, Newborn ; Organ Specificity ; Puberty ; Symbiosis ; }, abstract = {The &quot;holobiont&quot; concept, defined as the collective contribution of the eukaryotic and prokaryotic counterparts to the multicellular organism, introduces a complex definition of individuality enabling a new comprehensive view of human evolution and personalized characteristics. Here, we provide snapshots of the evolving microbial-host associations and relations during distinct milestones across the lifespan of a human being. We discuss the current knowledge of biological symbiosis between the microbiome and its host and portray the challenges in understanding these interactions and their potential effects on human physiology, including microbiome-nervous system inter-relationship and its relevance to human variation and individuality.}, }
@article {pmid29244764, year = {2017}, author = {Ugarelli, K and Chakrabarti, S and Laas, P and Stingl, U}, title = {The Seagrass Holobiont and Its Microbiome.}, journal = {Microorganisms}, volume = {5}, number = {4}, pages = {}, doi = {10.3390/microorganisms5040081}, pmid = {29244764}, issn = {2076-2607}, abstract = {Seagrass meadows are ecologically and economically important components of many coastal areas worldwide. Ecosystem services provided by seagrasses include reducing the number of microbial pathogens in the water, providing food, shelter and nurseries for many species, and decreasing the impact of waves on the shorelines. A global assessment reported that 29% of the known areal extent of seagrasses has disappeared since seagrass areas were initially recorded in 1879. Several factors such as direct and indirect human activity contribute to the demise of seagrasses. One of the main reasons for seagrass die-offs all over the world is increased sulfide concentrations in the sediment that result from the activity of sulfate-reducing prokaryotes, which perform the last step of the anaerobic food chain in marine sediments and reduce sulfate to H₂S. Recent seagrass die-offs, e.g., in the Florida and Biscayne Bays, were caused by an increase in pore-water sulfide concentrations in the sediment, which were the combined result of unfavorable environmental conditions and the activities of various groups of heterotrophic bacteria in the sulfate-rich water-column and sediment that are stimulated through increased nutrient concentrations. Under normal circumstances, seagrasses are able to withstand low levels of sulfide, probably partly due to microbial symbionts, which detoxify sulfide by oxidizing it to sulfur or sulfate. Novel studies are beginning to give greater insights into the interactions of microbes and seagrasses, not only in the sulfur cycle. Here, we review the literature on the basic ecology and biology of seagrasses and focus on studies describing their microbiome.}, }
@article {pmid29222444, year = {2018}, author = {Lesser, MP and Morrow, KM and Pankey, SM and Noonan, SHC}, title = {Diazotroph diversity and nitrogen fixation in the coral Stylophora pistillata from the Great Barrier Reef.}, journal = {The ISME journal}, volume = {12}, number = {3}, pages = {813-824}, doi = {10.1038/s41396-017-0008-6}, pmid = {29222444}, issn = {1751-7370}, abstract = {Diazotrophs, both Bacteria and Archaea, capable of fixing nitrogen (N2), are present in the tissues and mucous, of corals and can supplement the coral holobiont nitrogen budget with fixed nitrogen (N) in the form of ammonia (NH3). Stylophora pistillata from Heron Island on the Great Barrier Reef collected at 5 and 15 m, and experimentally manipulated in the laboratory, showed that the rates of net photosynthesis, steady state quantum yields of photosystem II (PSII) fluorescence (∆Fv/Fm') and calcification varied based on irradiance as expected. Rates of N2 fixation were, however, invariant across treatments while the amount of fixed N contributing to Symbiodinium spp. N demand is irradiance dependent. Additionally, both the Symbiodinium and diazotrophic communities are significantly different based on depth, and novel Cluster V nifH gene phylotypes, which are not known to fix nitrogen, were recovered. A functional analysis using PICRUSt also showed that shallow corals were enriched in genes involved in nitrogen metabolism, and N2 fixation specifically. Corals have evolved a number of strategies to derive nitrogen from organic (e.g., heterotrophic feeding) and inorganic sources (e.g., N2 fixation) to maintain critical pathways such as protein synthesis to succeed ecologically in nitrogen-limited habitats.}, }
@article {pmid29211049, year = {2017}, author = {Shapiro, JA}, title = {Living Organisms Author Their Read-Write Genomes in Evolution.}, journal = {Biology}, volume = {6}, number = {4}, pages = {}, doi = {10.3390/biology6040042}, pmid = {29211049}, issn = {2079-7737}, abstract = {Evolutionary variations generating phenotypic adaptations and novel taxa resulted from complex cellular activities altering genome content and expression: (i) Symbiogenetic cell mergers producing the mitochondrion-bearing ancestor of eukaryotes and chloroplast-bearing ancestors of photosynthetic eukaryotes; (ii) interspecific hybridizations and genome doublings generating new species and adaptive radiations of higher plants and animals; and, (iii) interspecific horizontal DNA transfer encoding virtually all of the cellular functions between organisms and their viruses in all domains of life. Consequently, assuming that evolutionary processes occur in isolated genomes of individual species has become an unrealistic abstraction. Adaptive variations also involved natural genetic engineering of mobile DNA elements to rewire regulatory networks. In the most highly evolved organisms, biological complexity scales with &quot;non-coding&quot; DNA content more closely than with protein-coding capacity. Coincidentally, we have learned how so-called &quot;non-coding&quot; RNAs that are rich in repetitive mobile DNA sequences are key regulators of complex phenotypes. Both biotic and abiotic ecological challenges serve as triggers for episodes of elevated genome change. The intersections of cell activities, biosphere interactions, horizontal DNA transfers, and non-random Read-Write genome modifications by natural genetic engineering provide a rich molecular and biological foundation for understanding how ecological disruptions can stimulate productive, often abrupt, evolutionary transformations.}, }
@article {pmid29194919, year = {2018}, author = {Lavy, A and Keren, R and Yu, K and Thomas, BC and Alvarez-Cohen, L and Banfield, JF and Ilan, M}, title = {A novel Chromatiales bacterium is a potential sulfide oxidizer in multiple orders of marine sponges.}, journal = {Environmental microbiology}, volume = {20}, number = {2}, pages = {800-814}, doi = {10.1111/1462-2920.14013}, pmid = {29194919}, issn = {1462-2920}, support = {P42 ES004705/ES/NIEHS NIH HHS/United States ; }, abstract = {Sponges are benthic filter feeders that play pivotal roles in coupling benthic-pelagic processes in the oceans that involve transformation of dissolved and particulate organic carbon and nitrogen into biomass. While the contribution of sponge holobionts to the nitrogen cycle has been recognized in past years, their importance in the sulfur cycle, both oceanic and physiological, has only recently gained attention. Sponges in general, and Theonella swinhoei in particular, harbour a multitude of associated microorganisms that could affect sulfur cycling within the holobiont. We reconstructed the genome of a Chromatiales (class Gammaproteobacteria) bacterium from a metagenomic sequence dataset of a T. swinhoei-associated microbial community. This relatively abundant bacterium has the metabolic capability to oxidize sulfide yet displays reduced metabolic potential suggestive of its lifestyle as an obligatory symbiont. This bacterium was detected in multiple sponge orders, according to similarities in key genes such as 16S rRNA and polyketide synthase genes. Due to its sulfide oxidation metabolism and occurrence in many members of the Porifera phylum, we suggest naming the newly described taxon Candidatus Porisulfidus.}, }
@article {pmid29192903, year = {2018}, author = {Ziegler, M and Eguíluz, VM and Duarte, CM and Voolstra, CR}, title = {Rare symbionts may contribute to the resilience of coral-algal assemblages.}, journal = {The ISME journal}, volume = {12}, number = {1}, pages = {161-172}, doi = {10.1038/ismej.2017.151}, pmid = {29192903}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*physiology ; Coral Reefs ; Dinoflagellida/genetics/*physiology ; High-Throughput Nucleotide Sequencing ; *Symbiosis ; }, abstract = {The association between corals and photosynthetic dinoflagellates (Symbiodinium spp.) is the key to the success of reef ecosystems in highly oligotrophic environments, but it is also their Achilles' heel due to its vulnerability to local stressors and the effects of climate change. Research during the last two decades has shaped a view that coral host-Symbiodinium pairings are diverse, but largely exclusive. Deep sequencing has now revealed the existence of a rare diversity of cryptic Symbiodinium assemblages within the coral holobiont, in addition to one or a few abundant algal members. While the contribution of the most abundant resident Symbiodinium species to coral physiology is widely recognized, the significance of the rare and low abundant background Symbiodinium remains a matter of debate. In this study, we assessed how coral-Symbiodinium communities assemble and how rare and abundant components together constitute the Symbiodinium community by analyzing 892 coral samples comprising >110 000 unique Symbiodinium ITS2 marker gene sequences. Using network modeling, we show that host-Symbiodinium communities assemble in non-random 'clusters' of abundant and rare symbionts. Symbiodinium community structure follows the same principles as bacterial communities, for which the functional significance of rare members (the 'rare bacterial biosphere') has long been recognized. Importantly, the inclusion of rare Symbiodinium taxa in robustness analyses revealed a significant contribution to the stability of the host-symbiont community overall. As such, it highlights the potential functions rare symbionts may provide to environmental resilience of the coral holobiont.}, }
@article {pmid29175233, year = {2018}, author = {Miller, WB}, title = {Biological information systems: Evolution as cognition-based information management.}, journal = {Progress in biophysics and molecular biology}, volume = {134}, number = {}, pages = {1-26}, doi = {10.1016/j.pbiomolbio.2017.11.005}, pmid = {29175233}, issn = {1873-1732}, abstract = {An alternative biological synthesis is presented that conceptualizes evolutionary biology as an epiphenomenon of integrated self-referential information management. Since all biological information has inherent ambiguity, the systematic assessment of information is required by living organisms to maintain self-identity and homeostatic equipoise in confrontation with environmental challenges. Through their self-referential attachment to information space, cells are the cornerstone of biological action. That individualized assessment of information space permits self-referential, self-organizing niche construction. That deployment of information and its subsequent selection enacted the dominant stable unicellular informational architectures whose biological expressions are the prokaryotic, archaeal, and eukaryotic unicellular forms. Multicellularity represents the collective appraisal of equivocal environmental information through a shared information space. This concerted action can be viewed as systematized information management to improve information quality for the maintenance of preferred homeostatic boundaries among the varied participants. When reiterated in successive scales, this same collaborative exchange of information yields macroscopic organisms as obligatory multicellular holobionts. Cognition-Based Evolution (CBE) upholds that assessment of information precedes biological action, and the deployment of information through integrative self-referential niche construction and natural cellular engineering antecedes selection. Therefore, evolutionary biology can be framed as a complex reciprocating interactome that consists of the assessment, communication, deployment and management of information by self-referential organisms at multiple scales in continuous confrontation with environmental stresses.}, }
@article {pmid29170664, year = {2017}, author = {Grasis, JA}, title = {The Intra-Dependence of Viruses and the Holobiont.}, journal = {Frontiers in immunology}, volume = {8}, number = {}, pages = {1501}, doi = {10.3389/fimmu.2017.01501}, pmid = {29170664}, issn = {1664-3224}, support = {F32 AI098418/AI/NIAID NIH HHS/United States ; }, abstract = {Animals live in symbiosis with the microorganisms surrounding them. This symbiosis is necessary for animal health, as a symbiotic breakdown can lead to a disease state. The functional symbiosis between the host, and associated prokaryotes, eukaryotes, and viruses in the context of an environment is the holobiont. Deciphering these holobiont associations has proven to be both difficult and controversial. In particular, holobiont association with viruses has been of debate even though these interactions have been occurring since cellular life began. The controversy stems from the idea that all viruses are parasitic, yet their associations can also be beneficial. To determine viral involvement within the holobiont, it is necessary to identify and elucidate the function of viral populations in symbiosis with the host. Viral metagenome analyses identify the communities of eukaryotic and prokaryotic viruses that functionally associate within a holobiont. Similarly, analyses of the host in response to viral presence determine how these interactions are maintained. Combined analyses reveal how viruses interact within the holobiont and how viral symbiotic cooperation occurs. To understand how the holobiont serves as a functional unit, one must consider viruses as an integral part of disease, development, and evolution.}, }
@article {pmid29167578, year = {2017}, author = {Jarett, JK and MacManes, MD and Morrow, KM and Pankey, MS and Lesser, MP}, title = {Comparative Genomics of Color Morphs In the Coral Montastraea cavernosa.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {16039}, doi = {10.1038/s41598-017-16371-9}, pmid = {29167578}, issn = {2045-2322}, abstract = {Montastraea cavernosa is a common coral in the Caribbean basin found in several color morphs. To investigate the causes for brown and orange morphs we undertook a genomics approach on corals collected at the same time and depth in the Bahamas. The coral holobiont includes the host, symbiotic dinoflagellates (Symbiodinium spp.), and a diverse microbiome. While the coral host showed significant genetic differentiation between color morphs both the composition of the Symbiodinium spp. communities and the prokaryotic communities did not. Both targeted and global gene expression differences in the transcriptome of the host show no difference in fluorescent proteins while the metatranscriptome of the microbiome shows that pigments such as phycoerythrin and orange carotenoid protein of cyanobacterial origin are significantly greater in orange morphs, which is also consistent with the significantly greater number of cyanobacteria quantified by 16S rRNA reads and flow cytometry. The microbiome of orange color morphs expressed significantly more nitrogenase (nifH) transcripts consistent with their known ability to fix nitrogen. Both coral and Symbiodinium spp. transcriptomes from orange morphs had significantly increased expression of genes related to immune response and apoptosis, which may potentially be involved in maintaining and regulating the unique symbiont population in orange morphs.}, }
@article {pmid29158985, year = {2017}, author = {Weynberg, KD and Laffy, PW and Wood-Charlson, EM and Turaev, D and Rattei, T and Webster, NS and van Oppen, MJH}, title = {Coral-associated viral communities show high levels of diversity and host auxiliary functions.}, journal = {PeerJ}, volume = {5}, number = {}, pages = {e4054}, doi = {10.7717/peerj.4054}, pmid = {29158985}, issn = {2167-8359}, abstract = {Stony corals (Scleractinia) are marine invertebrates that form the foundation and framework upon which tropical reefs are built. The coral animal associates with a diverse microbiome comprised of dinoflagellate algae and other protists, bacteria, archaea, fungi and viruses. Using a metagenomics approach, we analysed the DNA and RNA viral assemblages of seven coral species from the central Great Barrier Reef (GBR), demonstrating that tailed bacteriophages of the Caudovirales dominate across all species examined, and ssDNA viruses, notably the Microviridae, are also prevalent. Most sequences with matches to eukaryotic viruses were assigned to six viral families, including four Nucleocytoplasmic Large DNA Viruses (NCLDVs) families: Iridoviridae, Phycodnaviridae, Mimiviridae, and Poxviridae, as well as Retroviridae and Polydnaviridae. Contrary to previous findings, Herpesvirales were rare in these GBR corals. Sequences of a ssRNA virus with similarities to the dinornavirus, Heterocapsa circularisquama ssRNA virus of the Alvernaviridae that infects free-living dinoflagellates, were observed in three coral species. We also detected viruses previously undescribed from the coral holobiont, including a virus that targets fungi associated with the coral species Acropora tenuis. Functional analysis of the assembled contigs indicated a high prevalence of latency-associated genes in the coral-associated viral assemblages, several host-derived auxiliary metabolic genes (AMGs) for photosynthesis (psbA, psbD genes encoding the photosystem II D1 and D2 proteins respectively), as well as potential nematocyst toxins and antioxidants (genes encoding green fluorescent-like chromoprotein). This study expands the currently limited knowledge on coral-associated viruses by characterising viral composition and function across seven GBR coral species.}, }
@article {pmid29108677, year = {2017}, author = {Ellison, MA and Ferrier, MD and Carney, SL}, title = {Salinity stress results in differential Hsp70 expression in the Exaiptasia pallida and Symbiodinium symbiosis.}, journal = {Marine environmental research}, volume = {132}, number = {}, pages = {63-67}, doi = {10.1016/j.marenvres.2017.10.006}, pmid = {29108677}, issn = {1879-0291}, mesh = {Animals ; Dinoflagellida/*physiology ; HSP70 Heat-Shock Proteins/*metabolism ; Salinity ; Sea Anemones/*physiology ; Stress, Physiological/*physiology ; Symbiosis ; }, abstract = {Abiotic factors affect cnidarian-algal symbiosis and, if severe enough, can result in bleaching. Increased temperature and light are well characterized causes of bleaching, but other factors like salinity can also stress the holobiont. In cnidarian-dinoflagellate systems, the expression of host genes, including heat shock protein 70 (Hsp70), changes due to thermal and light stress. In this experiment, we characterized to what extent salinity stress affects Hsp70 expression in the holobiont by simultaneously measuring host and symbiont Hsp70 expression in response to up to 8 h of hypo- and hypersaline conditions in the sea anemone Exaiptasia pallida and its intracellular symbiont Symbiodinium minutum. We show that E. pallida Hsp70 expression increases (6-11-fold) at high salinities whereas Symbiodinium Hsp70 expression shows little change (1.4-2.6-fold). These data suggest that cnidarian Hsp70 response is similar across multiple abiotic stressors further validating the Hsp70 gene as a biomarker for abiotic stress.}, }
@article {pmid29098358, year = {2018}, author = {Baumann, JH and Davies, SW and Aichelman, HE and Castillo, KD}, title = {Coral Symbiodinium Community Composition Across the Belize Mesoamerican Barrier Reef System is Influenced by Host Species and Thermal Variability.}, journal = {Microbial ecology}, volume = {75}, number = {4}, pages = {903-915}, doi = {10.1007/s00248-017-1096-6}, pmid = {29098358}, issn = {1432-184X}, support = {15802-1//Rufford Foundation/ ; OCE 1459522//Division of Ocean Sciences/ ; }, abstract = {Reef-building corals maintain a symbiotic relationship with dinoflagellate algae of the genus Symbiodinium, and this symbiosis is vital for the survival of the coral holobiont. Symbiodinium community composition within the coral host has been shown to influence a coral's ability to resist and recover from stress. A multitude of stressors including ocean warming, ocean acidification, and eutrophication have been linked to global scale decline in coral health and cover in recent decades. Three distinct thermal regimes (highTP, modTP, and lowTP) following an inshore-offshore gradient of declining average temperatures and thermal variation were identified on the Belize Mesoamerican Barrier Reef System (MBRS). Quantitative metabarcoding of the ITS-2 locus was employed to investigate differences and similarities in Symbiodinium genetic diversity of the Caribbean corals Siderastrea siderea, S. radians, and Pseudodiploria strigosa between the three thermal regimes. A total of ten Symbiodinium lineages were identified across the three coral host species. S. siderea was associated with distinct Symbiodinium communities; however, Symbiodinium communities of its congener, S. radians and P. strigosa, were more similar to one another. Thermal regime played a role in defining Symbiodinium communities in S. siderea but not S. radians or P. strigosa. Against expectations, Symbiodinium trenchii, a symbiont known to confer thermal tolerance, was dominant only in S. siderea at one sampled offshore site and was rare inshore, suggesting that coral thermal tolerance in more thermally variable inshore habitats is achieved through alternative mechanisms. Overall, thermal parameters alone were likely not the only primary drivers of Symbiodinium community composition, suggesting that environmental variables unrelated to temperature (i.e., light availability or nutrients) may play key roles in structuring coral-algal communities in Belize and that the relative importance of these environmental variables may vary by coral host species.}, }
@article {pmid29078340, year = {2017}, author = {Hartmann, AC and Petras, D and Quinn, RA and Protsyuk, I and Archer, FI and Ransome, E and Williams, GJ and Bailey, BA and Vermeij, MJA and Alexandrov, T and Dorrestein, PC and Rohwer, FL}, title = {Meta-mass shift chemical profiling of metabolomes from coral reefs.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {114}, number = {44}, pages = {11685-11690}, doi = {10.1073/pnas.1710248114}, pmid = {29078340}, issn = {1091-6490}, support = {P41 GM103484/GM/NIGMS NIH HHS/United States ; R03 CA211211/CA/NCI NIH HHS/United States ; }, mesh = {Animals ; Anthozoa/*metabolism ; Coral Reefs ; Metabolome ; Metabolomics/*methods ; Transcriptome ; }, abstract = {Untargeted metabolomics of environmental samples routinely detects thousands of small molecules, the vast majority of which cannot be identified. Meta-mass shift chemical (MeMSChem) profiling was developed to identify mass differences between related molecules using molecular networks. This approach illuminates metabolome-wide relationships between molecules and the putative chemical groups that differentiate them (e.g., H2, CH2, COCH2). MeMSChem profiling was used to analyze a publicly available metabolomic dataset of coral, algal, and fungal mat holobionts (i.e., the host and its associated microbes and viruses) sampled from some of Earth's most remote and pristine coral reefs. Each type of holobiont had distinct mass shift profiles, even when the analysis was restricted to molecules found in all samples. This result suggests that holobionts modify the same molecules in different ways and offers insights into the generation of molecular diversity. Three genera of stony corals had distinct patterns of molecular relatedness despite their high degree of taxonomic relatedness. MeMSChem profiles also partially differentiated between individuals, suggesting that every coral reef holobiont is a potential source of novel chemical diversity.}, }
@article {pmid29038057, year = {2017}, author = {Ahila, NK and Prakash, S and Manikandan, B and Ravindran, J and Prabhu, NM and Kannapiran, E}, title = {Bio-prospecting of coral (Porites lutea) mucus associated bacteria, Palk Bay reefs, Southeast coast of India.}, journal = {Microbial pathogenesis}, volume = {113}, number = {}, pages = {113-123}, doi = {10.1016/j.micpath.2017.09.056}, pmid = {29038057}, issn = {1096-1208}, mesh = {Animals ; Anthozoa/metabolism/*microbiology ; Bacillus/genetics/isolation &amp; purification/*metabolism ; Coral Reefs ; Enterobacter cloacae/genetics/isolation &amp; purification ; India ; Microbiota ; Mucus/*microbiology ; RNA, Ribosomal, 16S/genetics ; Vibrio/genetics/isolation &amp; purification/*metabolism ; }, abstract = {Coral mucus is one of the key localization in the coral holobiont, as this serves as an energy rich substrate for a wide range of abundant, diverse and multifunctional microbiota. However, very little is known about the functional role of bacterial communities in their associations with corals. In the present study, a total of 48 isolates were obtained from Porites lutea wherein the genus of Bacillus sp. and Vibrio sp. were predominant. Bio-prospecting the coral mucus revealed the existence of (10.42%) antagonistic bacteria against the tested bacterial pathogens. Molecular taxonomy (16S rRNA) proved the identity of these antagonistic bacteria belong to Enterobacter cloacae (CM1), Bacillus subtilis (CM2), Bacillus sp. (CM11) and Bacillus marisflavi (CM12). The secondary screening emphasized that the ethyl acetate extract of B. subtilis showed strong antagonistic effect, followed by the chloroform extract of E. cloacae and ethyl acetate extract of B. marisflavi. The antagonistic activity was statistically confirmed by Principal Component Analysis and Hierarchical Cluster Analysis. The privileged coral mucus associated bacterial (CMAB) solvent extracts inhibited the bacterial pathogens at 100 μg/ml (MIC) and ceased the growth at 200 μg/ml (MBC). The hemolytic and brine shrimp lethality assays disclosed the non-toxic nature of solvent extracts of CMAB. Altogether, the present investigation brought out the diversity of bacteria associated with the mucus of P. lutea. In addition, bio-prospecting corroborated the CMAB as the potential source of pharmacologically important bioactive compounds against a wide range of bacterial pathogens.}, }
@article {pmid29027742, year = {2018}, author = {Mera, H and Bourne, DG}, title = {Disentangling causation: complex roles of coral-associated microorganisms in disease.}, journal = {Environmental microbiology}, volume = {20}, number = {2}, pages = {431-449}, doi = {10.1111/1462-2920.13958}, pmid = {29027742}, issn = {1462-2920}, abstract = {Rapidly changing climate regimes combined with other anthropogenic pressures are implicated in increased disease epizootics among reef building corals, resulting in changing habitat structure. These accumulated stressors directly contribute to disease outbreaks by compromising the coral host immune system, modulating virulence of microbial pathogens and/or disrupting the balance within the microbiome of the holobiont. Disentangling coral disease causation has been challenging, and while progress has been made for certain diseases in terms of the roles the associated microorganisms play, it is evident that like in other marine or terrestrial systems, compromised host health cannot always be attributed to a single causative agent. Here, we summarize the current state in knowledge of microbial induced coral diseases, and discuss challenges and strategies to further disentangle disease causation. With the major environmental pressures coral reefs face over the next century, understanding interactions between host, environmental and microbial causative agent(s) that lead to disease, is still a priority to enable development of effective strategies for building resilience into coral populations.}, }
@article {pmid28967236, year = {2018}, author = {Sapp, M and Ploch, S and Fiore-Donno, AM and Bonkowski, M and Rose, LE}, title = {Protists are an integral part of the Arabidopsis thaliana microbiome.}, journal = {Environmental microbiology}, volume = {20}, number = {1}, pages = {30-43}, doi = {10.1111/1462-2920.13941}, pmid = {28967236}, issn = {1462-2920}, abstract = {Although protists occupy a vast range of habitats and are known to interact with plants among other things via disease suppression, competition or growth stimulation, their contributions to the 'phytobiome' are not well described. To contribute to a more comprehensive picture of the plant holobiont, we examined cercozoan and oomycete taxa living in association with the model plant Arabidopsis thaliana grown in two different soils. Soil, roots, leaves and wooden toothpicks were analysed before and after surface sterilization. Cercozoa were identified using 18S rRNA gene metabarcoding, whereas the Internal Transcribed Spacer 1 was used to determine oomycetes. Subsequent analyses revealed strong spatial structuring of protist communities between compartments, although oomycetes appeared more specialized than Cercozoa. With regards to oomycetes, only members of the Peronosporales and taxa belonging to the genus Globisporangium were identified as shared members of the A. thaliana microbiome. This also applied to cercozoan taxa belonging to the Glissomonadida and Cercomonadida. We identified a strong influence by edaphic factors on the rhizosphere, but not for the phyllosphere. Distinct differences of Cercozoa found preferably in wood or fresh plant material imply specific niche adaptations. Our results highlight the importance of micro-eukaryotes for the plant holobiont.}, }
@article {pmid28915923, year = {2017}, author = {Sharp, KH and Pratte, ZA and Kerwin, AH and Rotjan, RD and Stewart, FJ}, title = {Season, but not symbiont state, drives microbiome structure in the temperate coral Astrangia poculata.}, journal = {Microbiome}, volume = {5}, number = {1}, pages = {120}, doi = {10.1186/s40168-017-0329-8}, pmid = {28915923}, issn = {2049-2618}, mesh = {Animals ; Anthozoa/*microbiology ; Dinoflagellida/*physiology ; *Microbiota ; Seasons ; *Symbiosis ; }, abstract = {BACKGROUND: Understanding the associations among corals, their photosynthetic zooxanthella symbionts (Symbiodinium), and coral-associated prokaryotic microbiomes is critical for predicting the fidelity and strength of coral symbioses in the face of growing environmental threats. Most coral-microbiome associations are beneficial, yet the mechanisms that determine the composition of the coral microbiome remain largely unknown. Here, we characterized microbiome diversity in the temperate, facultatively symbiotic coral Astrangia poculata at four seasonal time points near the northernmost limit of the species range. The facultative nature of this system allowed us to test seasonal influence and symbiotic state (Symbiodinium density in the coral) on microbiome community composition.<br><br>RESULTS: Change in season had a strong effect on A. poculata microbiome composition. The seasonal shift was greatest upon the winter to spring transition, during which time A. poculata microbiome composition became more similar among host individuals. Within each of the four seasons, microbiome composition differed significantly from that of surrounding seawater but was surprisingly uniform between symbiotic and aposymbiotic corals, even in summer, when differences in Symbiodinium density between brown and white colonies are the highest, indicating that the observed seasonal shifts are not likely due to fluctuations in Symbiodinium density.<br><br>CONCLUSIONS: Our results suggest that symbiotic state may not be a primary driver of coral microbial community organization in A. poculata, which is a surprise given the long-held assumption that excess photosynthate is of importance to coral-associated microbes. Rather, other environmental or host factors, in this case, seasonal changes in host physiology associated with winter quiescence, may drive microbiome diversity. Additional studies of A. poculata and other facultatively symbiotic corals will provide important comparisons to studies of reef-building tropical corals and therefore help to identify basic principles of coral microbiome assembly, as well as functional relationships among holobiont members.}, }
@article {pmid28894639, year = {2017}, author = {Naim, MA and Smidt, H and Sipkema, D}, title = {Fungi found in Mediterranean and North Sea sponges: how specific are they?.}, journal = {PeerJ}, volume = {5}, number = {}, pages = {e3722}, doi = {10.7717/peerj.3722}, pmid = {28894639}, issn = {2167-8359}, abstract = {Fungi and other eukaryotes represent one of the last frontiers of microbial diversity in the sponge holobiont. In this study we employed pyrosequencing of 18S ribosomal RNA gene amplicons containing the V7 and V8 hypervariable regions to explore the fungal diversity of seven sponge species from the North Sea and the Mediterranean Sea. For most sponges, fungi were present at a low relative abundance averaging 0.75% of the 18S rRNA gene reads. In total, 44 fungal OTUs (operational taxonomic units) were detected in sponges, and 28 of these OTUs were also found in seawater. Twenty-two of the sponge-associated OTUs were identified as yeasts (mainly Malasseziales), representing 84% of the fungal reads. Several OTUs were related to fungal sequences previously retrieved from other sponges, but all OTUs were also related to fungi from other biological sources, such as seawater, sediments, lakes and anaerobic digesters. Therefore our data, supported by currently available data, point in the direction of mostly accidental presence of fungi in sponges and do not support the existence of a sponge-specific fungal community.}, }
@article {pmid28893194, year = {2017}, author = {Frazier, M and Helmkampf, M and Bellinger, MR and Geib, SM and Takabayashi, M}, title = {De novo metatranscriptome assembly and coral gene expression profile of Montipora capitata with growth anomaly.}, journal = {BMC genomics}, volume = {18}, number = {1}, pages = {710}, doi = {10.1186/s12864-017-4090-y}, pmid = {28893194}, issn = {1471-2164}, mesh = {Animals ; Anthozoa/*genetics/*growth &amp; development ; *Gene Expression Profiling ; Morphogenesis/genetics ; }, abstract = {BACKGROUND: Scleractinian corals are a vital component of coral reef ecosystems, and of significant cultural and economic value worldwide. As anthropogenic and natural stressors are contributing to a global decline of coral reefs, understanding coral health is critical to help preserve these ecosystems. Growth anomaly (GA) is a coral disease that has significant negative impacts on coral biology, yet our understanding of its etiology and pathology is lacking. In this study we used RNA-seq along with de novo metatranscriptome assembly and homology assignment to identify coral genes that are expressed in three distinct coral tissue types: tissue from healthy corals (&quot;healthy&quot;), GA lesion tissue from diseased corals (&quot;GA-affected&quot;) and apparently healthy tissue from diseased corals (&quot;GA-unaffected&quot;). We conducted pairwise comparisons of gene expression among these three tissue types to identify genes and pathways that help us to unravel the molecular pathology of this coral disease.<br><br>RESULTS: The quality-filtered de novo-assembled metatranscriptome contained 76,063 genes, of which 13,643 were identified as putative coral genes. Overall gene expression profiles of coral genes revealed high similarity between healthy tissue samples, in contrast to high variance among diseased samples. This indicates GA has a variety of genetic effects at the colony level, including on seemingly healthy (GA-unaffected) tissue. A total of 105 unique coral genes were found differentially expressed among tissue types. Pairwise comparisons revealed the greatest number of differentially expressed genes between healthy and GA-affected tissue (93 genes), followed by healthy and GA-unaffected tissue (33 genes), and GA-affected and -unaffected tissue (7 genes). The putative function of these genes suggests GA is associated with changes in the activity of genes involved in developmental processes and activation of the immune system.<br><br>CONCLUSION: This is one of the first transcriptome-level studies to investigate coral GA, and the first metatranscriptome assembly for the M. capitata holobiont. The gene expression data, metatranscriptome assembly and methodology developed through this study represent a significant addition to the molecular information available to further our understanding of this coral disease.}, }
@article {pmid28892512, year = {2017}, author = {Mezzasalma, V and Sandionigi, A and Bruni, I and Bruno, A and Lovicu, G and Casiraghi, M and Labra, M}, title = {Grape microbiome as a reliable and persistent signature of field origin and environmental conditions in Cannonau wine production.}, journal = {PloS one}, volume = {12}, number = {9}, pages = {e0184615}, doi = {10.1371/journal.pone.0184615}, pmid = {28892512}, issn = {1932-6203}, mesh = {Agriculture ; Bacteria/classification/genetics ; Biodiversity ; Cluster Analysis ; DNA Barcoding, Taxonomic ; *Environment ; Fungi/classification/genetics ; Geography ; Metagenome ; Metagenomics/methods ; *Microbiota ; Vitis/*microbiology ; *Wine ; }, abstract = {Grape berries harbor a wide range of microbes originating from the vineyard environment, many of which are recognized for their role in the must fermentation process shaping wine quality. To better clarify the contribution of the microbiome of grape fruits during wine fermentation, we used high-throughput sequencing to identify bacterial and fungi communities associated with berries and musts of Cannonau. This is the most important cultivar-wine of Sardinia (Italy) where most vineyards are cultivated without phytochemical treatments. Results suggested that microbiomes of berries collected at four different localities share a core composition characterized by Enterobacteriales, Pseudomonadales, Bacillales, and Rhodospirillales. However, any area seems to enrich berries microbiome with peculiar microbial traits. For example, berries belonging to the biodynamic vineyards of Mamoiada were rich in Bacillales typical of manure (i.e. Lysinibacillus, Bacillus, and Sporosarcina), whereas in the Santadi locality, berries showed soil bacteria such as Pasteurellales and Bacteroidales as well as Rhodospirillales and Lactobacillales which are commonly involved in wine fermentation. In the case of fungi, the most abundant taxa were Dothioraceae, Pleosporaceae, and Saccharomycodaceae, and although the proportion of these families varied among localities, they occurred ubiquitously in all vineyards. During vinification processes performed at the same wine cellar under controlled conditions and without using any yeast starter, more than 50% of bacteria groups of berries reached musts, and each locality had its own private bacteria signature, even if Saccharomyces cerevisiae represented the most abundant fungal species. This work suggests that natural berries microbiome could be influenced by pedoclimatic and anthropologic conditions (e.g., farming management), and the fruits' microorganisms persist during the fermentation process. For these reasons, a reliable wine genotyping should include the entire holobiont (plant and all its symbionts), and bioprospecting activities on grape microbiota could lead to improved viticulture yields and wine quality.}, }
@article {pmid28887506, year = {2017}, author = {Evans, JS and Erwin, PM and Shenkar, N and López-Legentil, S}, title = {Introduced ascidians harbor highly diverse and host-specific symbiotic microbial assemblages.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {11033}, doi = {10.1038/s41598-017-11441-4}, pmid = {28887506}, issn = {2045-2322}, abstract = {Many ascidian species have experienced worldwide introductions, exhibiting remarkable success in crossing geographic borders and adapting to local environmental conditions. To investigate the potential role of microbial symbionts in these introductions, we examined the microbial communities of three ascidian species common in North Carolina harbors. Replicate samples of the globally introduced species Distaplia bermudensis, Polyandrocarpa anguinea, and P. zorritensis (n = 5), and ambient seawater (n = 4), were collected in Wrightsville Beach, NC. Microbial communities were characterized by next-generation (Illumina) sequencing of partial (V4) 16S rRNA gene sequences. Ascidians hosted diverse symbiont communities, consisting of 5,696 unique microbial OTUs (at 97% sequenced identity) from 47 bacterial and three archaeal phyla. Permutational multivariate analyses of variance revealed clear differentiation of ascidian symbionts compared to seawater bacterioplankton, and distinct microbial communities inhabiting each ascidian species. 103 universal core OTUs (present in all ascidian replicates) were identified, including taxa previously described in marine invertebrate microbiomes with possible links to ammonia-oxidization, denitrification, pathogenesis, and heavy-metal processing. These results suggest ascidian microbial symbionts exhibit a high degree of host-specificity, forming intimate associations that may contribute to host adaptation to new environments via expanded tolerance thresholds and enhanced holobiont function.}, }
@article {pmid28861262, year = {2017}, author = {Rädecker, N and Pogoreutz, C and Ziegler, M and Ashok, A and Barreto, MM and Chaidez, V and Grupstra, CGB and Ng, YM and Perna, G and Aranda, M and Voolstra, CR}, title = {Assessing the effects of iron enrichment across holobiont compartments reveals reduced microbial nitrogen fixation in the Red Sea coral Pocillopora verrucosa.}, journal = {Ecology and evolution}, volume = {7}, number = {16}, pages = {6614-6621}, doi = {10.1002/ece3.3293}, pmid = {28861262}, issn = {2045-7758}, abstract = {The productivity of coral reefs in oligotrophic tropical waters is sustained by an efficient uptake and recycling of nutrients. In reef-building corals, the engineers of these ecosystems, this nutrient recycling is facilitated by a constant exchange of nutrients between the animal host and endosymbiotic photosynthetic dinoflagellates (zooxanthellae), bacteria, and other microbes. Due to the complex interactions in this so-called coral holobiont, it has proven difficult to understand the environmental limitations of productivity in corals. Among others, the micronutrient iron has been proposed to limit primary productivity due to its essential role in photosynthesis and bacterial processes. Here, we tested the effect of iron enrichment on the physiology of the coral Pocillopora verrucosa from the central Red Sea during a 12-day experiment. Contrary to previous reports, we did not see an increase in zooxanthellae population density or gross photosynthesis. Conversely, respiration rates were significantly increased, and microbial nitrogen fixation was significantly decreased. Taken together, our data suggest that iron is not a limiting factor of primary productivity in Red Sea corals. Rather, increased metabolic demands in response to iron enrichment, as evidenced by increased respiration rates, may reduce carbon (i.e., energy) availability in the coral holobiont, resulting in reduced microbial nitrogen fixation. This decrease in nitrogen supply in turn may exacerbate the limitation of other nutrients, creating a negative feedback loop. Thereby, our results highlight that the effects of iron enrichment appear to be strongly dependent on local environmental conditions and ultimately may depend on the availability of other nutrients.}, }
@article {pmid28857164, year = {2017}, author = {Brodie, J and Ball, SG and Bouget, FY and Chan, CX and De Clerck, O and Cock, JM and Gachon, C and Grossman, AR and Mock, T and Raven, JA and Saha, M and Smith, AG and Vardi, A and Yoon, HS and Bhattacharya, D}, title = {Biotic interactions as drivers of algal origin and evolution.}, journal = {The New phytologist}, volume = {216}, number = {3}, pages = {670-681}, doi = {10.1111/nph.14760}, pmid = {28857164}, issn = {1469-8137}, support = {BB/I013164/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Anthozoa/*physiology ; *Biological Evolution ; Chromatophores ; Dinoflagellida/physiology ; Eutrophication ; Host-Pathogen Interactions ; Phaeophyta/*physiology ; Photosynthesis ; Phycodnaviridae/pathogenicity ; Phylogeny ; Plastids ; Symbiosis ; }, abstract = {Contents 670 I. 671 II. 671 III. 676 IV. 678 678 References 678 SUMMARY: Biotic interactions underlie life's diversity and are the lynchpin to understanding its complexity and resilience within an ecological niche. Algal biologists have embraced this paradigm, and studies building on the explosive growth in omics and cell biology methods have facilitated the in-depth analysis of nonmodel organisms and communities from a variety of ecosystems. In turn, these advances have enabled a major revision of our understanding of the origin and evolution of photosynthesis in eukaryotes, bacterial-algal interactions, control of massive algal blooms in the ocean, and the maintenance and degradation of coral reefs. Here, we review some of the most exciting developments in the field of algal biotic interactions and identify challenges for scientists in the coming years. We foresee the development of an algal knowledgebase that integrates ecosystem-wide omics data and the development of molecular tools/resources to perform functional analyses of individuals in isolation and in populations. These assets will allow us to move beyond mechanistic studies of a single species towards understanding the interactions amongst algae and other organisms in both the laboratory and the field.}, }
@article {pmid28839925, year = {2017}, author = {Hurst, GDD}, title = {Extended genomes: symbiosis and evolution.}, journal = {Interface focus}, volume = {7}, number = {5}, pages = {20170001}, doi = {10.1098/rsfs.2017.0001}, pmid = {28839925}, issn = {2042-8898}, abstract = {Many aspects of an individual's biology derive from its interaction with symbiotic microbes, which further define many aspects of the ecology and evolution of the host species. The centrality of microbes in the function of individual organisms has given rise to the concept of the holobiont-that an individual's biology is best understood as a composite of the 'host organism' and symbionts within. This concept has been further elaborated to posit the holobiont as a unit of selection. In this review, I critically examine whether it is useful to consider holobionts as a unit of selection. I argue that microbial heredity-the direct passage of microbes from parent to offspring-is a key factor determining the degree to which the holobiont can usefully be considered a level of selection. Where direct vertical transmission (VT) is common, microbes form part of extended genomes whose dynamics can be modelled with simple population genetics, but that nevertheless have subtle quantitative distinctions from the classic mutation/selection model for nuclear genes. Without direct VT, the correlation between microbial fitness and host individual fitness erodes, and microbe fitness becomes associated with host survival only (rather than reproduction). Furthermore, turnover of microbes within a host may lessen associations between microbial fitness with host survival, and in polymicrobial communities, microbial fitness may derive largely from the ability to outcompete other microbes, to avoid host immune clearance and to minimize mortality through phage infection. These competing selection pressures make holobiont fitness a very minor consideration in determining symbiont evolution. Nevertheless, the importance of non-heritable microbes in organismal function is undoubted-and as such the evolutionary and ecological processes giving rise to variation and evolution of the microbes within and between host individuals represent a key research area in biology.}, }
@article {pmid28835914, year = {2017}, author = {Ochsenkühn, MA and Röthig, T and D'Angelo, C and Wiedenmann, J and Voolstra, CR}, title = {The role of floridoside in osmoadaptation of coral-associated algal endosymbionts to high-salinity conditions.}, journal = {Science advances}, volume = {3}, number = {8}, pages = {e1602047}, doi = {10.1126/sciadv.1602047}, pmid = {28835914}, issn = {2375-2548}, abstract = {The endosymbiosis between Symbiodinium dinoflagellates and stony corals provides the foundation of coral reef ecosystems. The survival of these ecosystems is under threat at a global scale, and better knowledge is needed to conceive strategies for mitigating future reef loss. Environmental disturbance imposing temperature, salinity, and nutrient stress can lead to the loss of the Symbiodinium partner, causing so-called coral bleaching. Some of the most thermotolerant coral-Symbiodinium associations occur in the Persian/Arabian Gulf and the Red Sea, which also represent the most saline coral habitats. We studied whether Symbiodinium alter their metabolite content in response to high-salinity environments. We found that Symbiodinium cells exposed to high salinity produced high levels of the osmolyte 2-O-glycerol-α-d-galactopyranoside (floridoside), both in vitro and in their coral host animals, thereby increasing their capacity and, putatively, the capacity of the holobiont to cope with the effects of osmotic stress in extreme environments. Given that floridoside has been previously shown to also act as an antioxidant, this osmolyte may serve a dual function: first, to serve as a compatible organic osmolyte accumulated by Symbiodinium in response to elevated salinities and, second, to counter reactive oxygen species produced as a consequence of potential salinity and heat stress.}, }
@article {pmid28826642, year = {2018}, author = {Moissl-Eichinger, C and Pausan, M and Taffner, J and Berg, G and Bang, C and Schmitz, RA}, title = {Archaea Are Interactive Components of Complex Microbiomes.}, journal = {Trends in microbiology}, volume = {26}, number = {1}, pages = {70-85}, doi = {10.1016/j.tim.2017.07.004}, pmid = {28826642}, issn = {1878-4380}, abstract = {Recent findings have shaken our picture of the biology of the archaea and revealed novel traits beyond archaeal extremophily and supposed 'primitiveness'. The archaea constitute a considerable fraction of the Earth's ecosystems, and their potential to shape their surroundings by a profound interaction with their biotic and abiotic environment has been recognized. Moreover, archaea have been identified as a substantial component, or even as keystone species, in complex microbiomes - in the environment or accompanying a holobiont. Species of the Euryarchaeota (methanogens, halophiles) and Thaumarchaeota, in particular, have the capacity to coexist in plant, animal, and human microbiomes, where syntrophy allows them to thrive under energy-deficiency stress. Due to methodological limitations, the archaeome remains mysterious, and many questions with respect to potential pathogenicity, function, and structural interactions with their host and other microorganisms remain.}, }
@article {pmid28824625, year = {2017}, author = {Rader, BA}, title = {Alkaline Phosphatase, an Unconventional Immune Protein.}, journal = {Frontiers in immunology}, volume = {8}, number = {}, pages = {897}, doi = {10.3389/fimmu.2017.00897}, pmid = {28824625}, issn = {1664-3224}, support = {R15 GM119100/GM/NIGMS NIH HHS/United States ; }, abstract = {Recent years have seen an increase in the number of studies focusing on alkaline phosphatases (APs), revealing an expanding complexity of function of these enzymes. Of the four human AP (hAP) proteins, most is known about tissue non-specific AP (TNAP) and intestinal AP (IAP). This review highlights current understanding of TNAP and IAP in relation to human health and disease. TNAP plays a role in multiple processes, including bone mineralization, vitamin B6 metabolism, and neurogenesis, is the genetic cause of hypophosphatasia, influences inflammation through regulation of purinergic signaling, and has been implicated in Alzheimer's disease. IAP regulates fatty acid absorption and has been implicated in the regulation of diet-induced obesity and metabolic syndrome. IAP and TNAP can dephosphorylate bacterial-derived lipopolysaccharide, and IAP has been identified as a potential regulator of the composition of the intestinal microbiome, an evolutionarily conserved function. Endogenous and recombinant bovine APs and recombinant hAPs are currently being explored for their potential as pharmacological agents to treat AP-associated diseases and mitigate multiple sources of inflammation. Continued research on these versatile proteins will undoubtedly provide insight into human pathophysiology, biochemistry, and the human holobiont.}, }
@article {pmid28818037, year = {2017}, author = {Brüwer, JD and Agrawal, S and Liew, YJ and Aranda, M and Voolstra, CR}, title = {Association of coral algal symbionts with a diverse viral community responsive to heat shock.}, journal = {BMC microbiology}, volume = {17}, number = {1}, pages = {174}, doi = {10.1186/s12866-017-1084-5}, pmid = {28818037}, issn = {1471-2180}, mesh = {Animals ; Anthozoa/*physiology/*virology ; Climate Change ; Cold Temperature ; Coral Reefs ; Darkness ; Dinoflagellida/physiology/virology ; Ecosystem ; Gene Expression Regulation, Viral ; Genes, Viral ; Hot Temperature ; Phylogeny ; Sequence Analysis, RNA ; *Symbiosis ; Viral Proteins/genetics/metabolism ; *Virus Physiological Phenomena ; Viruses/*classification/genetics ; }, abstract = {BACKGROUND: Stony corals provide the structural foundation of coral reef ecosystems and are termed holobionts given they engage in symbioses, in particular with photosynthetic dinoflagellates of the genus Symbiodinium. Besides Symbiodinium, corals also engage with bacteria affecting metabolism, immunity, and resilience of the coral holobiont, but the role of associated viruses is largely unknown. In this regard, the increase of studies using RNA sequencing (RNA-Seq) to assess gene expression provides an opportunity to elucidate viral signatures encompassed within the data via careful delineation of sequence reads and their source of origin.<br><br>RESULTS: Here, we re-analyzed an RNA-Seq dataset from a cultured coral symbiont (Symbiodinium microadriaticum, Clade A1) across four experimental treatments (control, cold shock, heat shock, dark shock) to characterize associated viral diversity, abundance, and gene expression. Our approach comprised the filtering and removal of host sequence reads, subsequent phylogenetic assignment of sequence reads of putative viral origin, and the assembly and analysis of differentially expressed viral genes. About 15.46% (123 million) of all sequence reads were non-host-related, of which <1% could be classified as archaea, bacteria, or virus. Of these, 18.78% were annotated as virus and comprised a diverse community consistent across experimental treatments. Further, non-host related sequence reads assembled into 56,064 contigs, including 4856 contigs of putative viral origin that featured 43 differentially expressed genes during heat shock. The differentially expressed genes included viral kinases, ubiquitin, and ankyrin repeat proteins (amongst others), which are suggested to help the virus proliferate and inhibit the algal host's antiviral response.<br><br>CONCLUSION: Our results suggest that a diverse viral community is associated with coral algal endosymbionts of the genus Symbiodinium, which prompts further research on their ecological role in coral health and resilience.}, }
@article {pmid28799900, year = {2017}, author = {Vorholt, JA and Vogel, C and Carlström, CI and Müller, DB}, title = {Establishing Causality: Opportunities of Synthetic Communities for Plant Microbiome Research.}, journal = {Cell host &amp; microbe}, volume = {22}, number = {2}, pages = {142-155}, doi = {10.1016/j.chom.2017.07.004}, pmid = {28799900}, issn = {1934-6069}, mesh = {Bacteria/genetics ; Bacterial Physiological Phenomena ; Ecosystem ; Host-Pathogen Interactions ; Metagenome ; Microbial Consortia/physiology ; Microbial Interactions ; *Microbiota/genetics/physiology ; Plant Roots/microbiology ; Plants/*microbiology ; Soil Microbiology ; }, abstract = {Plant microbiome research highlights the importance of indigenous microbial communities for host phenotypes such as growth and health. It aims to discover the molecular basis by which host-microbe and microbe-microbe interactions shape and maintain microbial communities and to understand the role of individual microorganisms, as well as their collective ecosystem function. Here, we discuss reductionist approaches to disentangle the inherent complexity of interactions in situ. Experimentally tractable, synthetic communities enable testing of hypotheses by targeted manipulation in gnotobiotic systems. Modifications of microbial, host, and environmental parameters allow for the quantitative assessment of host and microbe characteristics with dynamic and spatial resolution. We summarize first insights from this emerging field and discuss current challenges and limitations. Using multifaceted approaches to detect interactions and functions will provide new insights into the fundamental biology of plant-microbe interactions and help to harness the power of the microbiome.}, }
@article {pmid28787582, year = {2017}, author = {Roossinck, MJ and Bazán, ER}, title = {Symbiosis: Viruses as Intimate Partners.}, journal = {Annual review of virology}, volume = {4}, number = {1}, pages = {123-139}, doi = {10.1146/annurev-virology-110615-042323}, pmid = {28787582}, issn = {2327-0578}, mesh = {Animals ; Bacteria/genetics ; DNA, Viral/*genetics ; Evolution, Molecular ; Genome ; *Host-Pathogen Interactions ; Humans ; Phylogeny ; *Symbiosis ; *Virus Physiological Phenomena ; }, abstract = {Viruses must establish an intimate relationship with their hosts and vectors in order to infect, replicate, and disseminate; hence, viruses can be considered as symbionts with their hosts. Symbiotic relationships encompass different lifestyles, including antagonistic (or pathogenic, the most well-studied lifestyle for viruses), commensal (probably the most common lifestyle), and mutualistic (important beneficial partners). Symbiotic relationships can shape the evolution of the partners in a holobiont, and placing viruses in this context provides an important framework for understanding virus-host relationships and virus ecology. Although antagonistic relationships are thought to lead to coevolution, this is not always clear in virus-host interactions, and impacts on evolution may be complex. Commensalism implies a hitchhiking role for viruses-selfish elements just along for the ride. Mutualistic relationships have been described in detail in the past decade, and they reveal how important viruses are in considering host ecology. Ultimately, symbiosis can lead to symbiogenesis, or speciation through fusion, and the presence of large amounts of viral sequence in the genomes of everything from bacteria to humans, including some important functional genes, illustrates the significance of viral symbiogenesis in the evolution of all life on Earth.}, }
@article {pmid28785524, year = {2017}, author = {Conlan, JA and Rocker, MM and Francis, DS}, title = {A comparison of two common sample preparation techniques for lipid and fatty acid analysis in three different coral morphotypes reveals quantitative and qualitative differences.}, journal = {PeerJ}, volume = {5}, number = {}, pages = {e3645}, doi = {10.7717/peerj.3645}, pmid = {28785524}, issn = {2167-8359}, abstract = {Lipids are involved in a host of biochemical and physiological processes in corals. Therefore, changes in lipid composition reflect changes in the ecology, nutrition, and health of corals. As such, accurate lipid extraction, quantification, and identification is critical to obtain comprehensive insight into a coral's condition. However, discrepancies exist in sample preparation methodology globally, and it is currently unknown whether these techniques generate analogous results. This study compared the two most common sample preparation techniques for lipid analysis in corals: (1) tissue isolation by air-spraying and (2) crushing the coral in toto. Samples derived from each preparation technique were subsequently analysed to quantify lipids and their constituent classes and fatty acids in four common, scleractinian coral species representing three distinct morphotypes (Acropora millepora, Montipora crassotuberculata, Porites cylindrica, and Pocillopora damicornis). Results revealed substantial amounts of organic material, including lipids, retained in the skeletons of all species following air-spraying, causing a marked underestimation of total lipid concentration using this method. Moreover, lipid class and fatty acid compositions between the denuded skeleton and sprayed tissue were substantially different. In particular, the majority of the total triacylglycerol and total fatty acid concentrations were retained in the skeleton (55-69% and 56-64%, respectively). As such, the isolated, sprayed tissue cannot serve as a reliable proxy for lipid quantification or identification in the coral holobiont. The in toto crushing method is therefore recommended for coral sample preparation prior to lipid analysis to capture the lipid profile of the entire holobiont, permitting accurate diagnoses of coral condition.}, }
@article {pmid28766142, year = {2017}, author = {Leite, L and Jude-Lemeilleur, F and Raymond, N and Henriques, I and Garabetian, F and Alves, A}, title = {Phylogenetic diversity and functional characterization of the Manila clam microbiota: a culture-based approach.}, journal = {Environmental science and pollution research international}, volume = {24}, number = {27}, pages = {21721-21732}, doi = {10.1007/s11356-017-9838-z}, pmid = {28766142}, issn = {1614-7499}, support = {UID/AMB/50017/2013//Fundação para a Ciência e a Tecnologia/ ; IF/00835/2013//Fundação para a Ciência e a Tecnologia/ ; IF/00492/2013//Fundação para a Ciência e a Tecnologia/ ; SFRH/BD/86879/2012//Fundação para a Ciência e a Tecnologia/ ; TC-08_12//Programa de Ações Universitárias Integradas 
Luso-Francesas (PAULIF)/ ; }, abstract = {According to the hologenome theory, the microbiota contributes to the fitness of the holobiont having an important role in its adaptation, survival, development, health, and evolution. Environmental stress also affects the microbiota and its capability to assist the holobiont in coping with stress factors. Here, we analyzed the diversity of cultivable bacteria associated with Manila clam tissues (mantle, gills, hemolymph) in two non-contaminated sites (Portugal and France) and one metal-contaminated site (Portugal). A total of 240 isolates were obtained. Representative isolates (n = 198) of the overall diversity were identified by 16S rDNA sequencing and subjected to functional characterization. Isolates affiliated with Proteobacteria, Actinobacteria, Firmicutes, and Bacteroidetes. Proteobacteria (mostly Pseudoalteromonadaceae and Vibrionaceae) were dominant in non-contaminated sites while Actinobacteria (mostly Microbacteriaceae) dominated in the metal-contaminated site. The main factor affecting the microbiota composition was contamination. No significant differences were observed between clam tissues and geographic regions. Several isolates tested positive for antibacterial activity, biofilm formation, protease, and siderophore production. The results show that the Manila clam harbors a diverse microbiota that may contribute to clam protection and overall fitness, as well as to its adaptation to stressful environments. In addition, the Manila clam microbiota is revealed as a promising source of novel probiotics with potential application in aquaculture.}, }
@article {pmid28732267, year = {2017}, author = {Sánchez-Cañizares, C and Jorrín, B and Poole, PS and Tkacz, A}, title = {Understanding the holobiont: the interdependence of plants and their microbiome.}, journal = {Current opinion in microbiology}, volume = {38}, number = {}, pages = {188-196}, doi = {10.1016/j.mib.2017.07.001}, pmid = {28732267}, issn = {1879-0364}, mesh = {*Ecosystem ; *Microbiota ; Plants/*microbiology ; }, abstract = {The holobiont is composed by the plant and its microbiome. In a similar way to ecological systems of higher organisms, the holobiont shows interdependent and complex dynamics [1,2]. While plants originate from seeds, the microbiome has a multitude of sources. The assemblage of these communities depends on the interaction between the emerging seedling and its surrounding environment, with soil being the main source. These microbial communities are controlled by the plant through different strategies, such as the specific profile of root exudates and its immune system. Despite this control, the microbiome is still able to adapt and thrive. The molecular knowledge behind these interactions and microbial '-omic' technologies are developing to the point of enabling holobiont engineering. For a long time microorganisms were in the background of plant biology but new multidisciplinary approaches have led to an appreciation of the importance of the holobiont, where plants and microbes are interdependent.}, }
@article {pmid28729652, year = {2017}, author = {Johnston, EC and Forsman, ZH and Flot, JF and Schmidt-Roach, S and Pinzón, JH and Knapp, ISS and Toonen, RJ}, title = {A genomic glance through the fog of plasticity and diversification in Pocillopora.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {5991}, doi = {10.1038/s41598-017-06085-3}, pmid = {28729652}, issn = {2045-2322}, abstract = {Scleractinian corals of the genus Pocillopora (Lamarck, 1816) are notoriously difficult to identify morphologically with considerable debate on the degree to which phenotypic plasticity, introgressive hybridization and incomplete lineage sorting obscure well-defined taxonomic lineages. Here, we used RAD-seq to resolve the phylogenetic relationships among seven species of Pocillopora represented by 15 coral holobiont metagenomic libraries. We found strong concordance between the coral holobiont datasets, reads that mapped to the Pocillopora damicornis (Linnaeus, 1758) transcriptome, nearly complete mitochondrial genomes, 430 unlinked high-quality SNPs shared across all Pocillopora taxa, and a conspecificity matrix of the holobiont dataset. These datasets also show strong concordance with previously published clustering of the mitochondrial clades based on the mtDNA open reading frame (ORF). We resolve seven clear monophyletic groups, with no evidence for introgressive hybridization among any but the most recently derived sister species. In contrast, ribosomal and histone datasets, which are most commonly used in coral phylogenies to date, were less informative and contradictory to these other datasets. These data indicate that extant Pocillopora species diversified from a common ancestral lineage within the last ~3 million years. Key to this evolutionary success story may be the high phenotypic plasticity exhibited by Pocillopora species.}, }
@article {pmid28724687, year = {2017}, author = {Morimoto, J and Simpson, SJ and Ponton, F}, title = {Direct and trans-generational effects of male and female gut microbiota in Drosophila melanogaster.}, journal = {Biology letters}, volume = {13}, number = {7}, pages = {}, doi = {10.1098/rsbl.2016.0966}, pmid = {28724687}, issn = {1744-957X}, mesh = {Acetobacter ; Animals ; Drosophila melanogaster ; Female ; *Gastrointestinal Microbiome ; Male ; Reproduction ; Sexual Behavior, Animal ; }, abstract = {There is increasing evidence of the far-reaching effects of gut bacteria on physiological and behavioural traits, yet the fitness-related consequences of changes in the gut bacteria composition of sexually interacting individuals remain unknown. To address this question, we manipulated the gut microbiota of fruit flies, Drosophila melanogaster, by monoinfecting flies with either Acetobacter pomorum (AP) or Lactobacillus plantarum (LP). Re-inoculated individuals were paired in all treatment combinations. LP-infected males had longer mating duration and induced higher short-term offspring production in females compared with AP-infected males. Furthermore, females of either re-inoculation state mated with AP-infected males were more likely to have zero offspring after mating, suggesting a negative effect of AP on male fertility. Finally, we found that the effects of male and female gut bacteria interacted to modulate their daughters', but not sons' body mass, revealing a new trans-generational effect of parental gut microbiota. In conclusion, this study shows direct and trans-generational effects of the gut microbiota on mating and reproduction.}, }
@article {pmid28717593, year = {2017}, author = {Gerth, M and Hurst, GDD}, title = {Short reads from honey bee (Apis sp.) sequencing projects reflect microbial associate diversity.}, journal = {PeerJ}, volume = {5}, number = {}, pages = {e3529}, doi = {10.7717/peerj.3529}, pmid = {28717593}, issn = {2167-8359}, abstract = {High throughput (or 'next generation') sequencing has transformed most areas of biological research and is now a standard method that underpins empirical study of organismal biology, and (through comparison of genomes), reveals patterns of evolution. For projects focused on animals, these sequencing methods do not discriminate between the primary target of sequencing (the animal genome) and 'contaminating' material, such as associated microbes. A common first step is to filter out these contaminants to allow better assembly of the animal genome or transcriptome. Here, we aimed to assess if these 'contaminations' provide information with regard to biologically important microorganisms associated with the individual. To achieve this, we examined whether the short read data from Apis retrieved elements of its well established microbiome. To this end, we screened almost 1,000 short read libraries of honey bee (Apis sp.) DNA sequencing project for the presence of microbial sequences, and find sequences from known honey bee microbial associates in at least 11% of them. Further to this, we screened ∼500 Apis RNA sequencing libraries for evidence of viral infections, which were found to be present in about half of them. We then used the data to reconstruct draft genomes of three Apis associated bacteria, as well as several viral strains de novo. We conclude that 'contamination' in short read sequencing libraries can provide useful genomic information on microbial taxa known to be associated with the target organisms, and may even lead to the discovery of novel associations. Finally, we demonstrate that RNAseq samples from experiments commonly carry uneven viral loads across libraries. We note variation in viral presence and load may be a confounding feature of differential gene expression analyses, and as such it should be incorporated as a random factor in analyses.}, }
@article {pmid28710460, year = {2017}, author = {Pineda, MC and Strehlow, B and Sternel, M and Duckworth, A and Haan, JD and Jones, R and Webster, NS}, title = {Effects of sediment smothering on the sponge holobiont with implications for dredging management.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {5156}, doi = {10.1038/s41598-017-05243-x}, pmid = {28710460}, issn = {2045-2322}, abstract = {One of the ways dredging can affect benthic habitats is through high levels of sediment deposition, which has the potential to smother sessile organisms such as sponges. In order to provide pressure-response values to sedimentation and tease apart the different cause-effect pathways of high turbidity, 5 sponge species, including heterotrophic and phototrophic nutritional modes, were exposed for up to 30 d to multiple sediment deposition events, each of which resulted in an initial covering of 80-100% of the surface of the sponges in a layer ~0.5 mm thick. The response of the sponges was examined using a suite of different response variables including growth, respiration, lipid content, community composition of the microbial symbionts, and maximum quantum yield and chlorophyll content of the phototrophic symbionts. Different species showed different mechanisms of sediment rejection and different patterns of sediment clearance. All species survived the treatments, were able to tolerate high levels of partial covering of their surfaces, and for most species the treatment did not alter the health of the sponge holobiont. Results from this study will guide interpretation of experiments examining the combined effects of all three dredging-related pressures, and aid the development of water quality thresholds for impact prediction purposes.}, }
@article {pmid28694508, year = {2017}, author = {Pineda, MC and Strehlow, B and Sternel, M and Duckworth, A and Jones, R and Webster, NS}, title = {Effects of suspended sediments on the sponge holobiont with implications for dredging management.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {4925}, doi = {10.1038/s41598-017-05241-z}, pmid = {28694508}, issn = {2045-2322}, abstract = {Dredging can cause high suspended sediment concentrations (SSC) in the water column, posing a hazard to filter feeding organisms like sponges as sediment may clog their aquiferous systems and reduce feeding. In order to provide pressure-response values for sponges to SSC and tease apart the cause:effect pathways of dredging pressures, five heterotrophic and phototrophic species were experimentally exposed to a range of dredging-relevant SSC of up to 100 mg L-1, with light compensation across treatments to ensure that SSC was the primary physical parameter. This study shows that some sponge species exposed to high SSC (≥23 mg L-1) for extended periods (28 d) have lower survival, increased necrosis and depletion of energy reserves. In contrast, SSC of ≤10 mg L-1 caused few, if any, negative effects and is thus suggested as a prudent sub-lethal threshold for sponges. Microbial communities did not change significantly among SSC treatments, although a nutritional shift from mixotrophy towards increased phototrophy was detected for some sponge species exposed to high SSC. Importantly however, it is expected that the combined effect of SSC with low light availability and sediment smothering as occurs during dredging operations will increase the negative effects on sponges.}, }
@article {pmid28682223, year = {2017}, author = {Burcelin, R}, title = {[Gut microbiota and immune crosstalk in metabolic disease].}, journal = {Biologie aujourd'hui}, volume = {211}, number = {1}, pages = {1-18}, doi = {10.1051/jbio/2017008}, pmid = {28682223}, issn = {2105-0686}, mesh = {Animals ; Dysbiosis/complications/immunology/microbiology/prevention &amp; control ; Gastrointestinal Microbiome/immunology/*physiology ; Gastrointestinal Tract/immunology/metabolism ; Humans ; Immune System/*physiology ; Inflammation/etiology/microbiology ; Metabolic Diseases/*immunology/metabolism/*microbiology ; Signal Transduction/immunology ; }, abstract = {The aim of the review is to discuss about the role played by the defence crosstalk between the gut microbiota and the intestinal immune system, in the development of metabolic disease focusing on obesity and diabetes. Starting from physiological and pathological stand points and based on the latest published data, this review is addressing how the concept of the hologenome theory of evolution can drive the fate of metabolic disease. The notion of &quot;metabolic infection&quot; to explain the &quot;metabolic inflammation&quot; is discussed. This imply comments about the process of bacterial translocation and impaired intestinal immune defense against commensals. Eventually this review sets the soil for personalized medicine. The monthly increase in the number of publications on the gut microbiota to intestinal immune defense and the control of metabolism demonstrate the importance of this field of investigation. The notion of commensal as &quot;self or non-self&quot; has to be reevaluated in the light of the current data. Furthermore, data demonstrate the major role played by short chain fatty acids, secondary bile acids, LPS, peptidoglycans, indole derivatives, and other bacteria-related molecules on the shaping of cells involved in the intestinal protection against commensals is now becoming a central player in the incidence of metabolic diseases. The literature demonstrates that the onset of metabolic diseases and some specific co-morbidities can be explained by a gut microbiota to intestinal immune system crosstalk. Therefore, one should now consider this avenue of investigation as a putative source of biomarkers and therapeutic targets to personalize the treatment of metabolic disease and its co-morbidities. Gut microbiota is considered as a major regulator of metabolic disease. This reconciles the notion of metabolic inflammation and the epidemic development of the disease. In addition to evidence showing that a specific gut microbiota characterizes patients with obesity, type 2 diabetes, and hepatic steatosis, the mechanisms causal to the disease could be related to the translocation of microbiota from the gut to the tissues, which induces inflammation. The mechanisms regulating such a process are based on the crosstalk between the gut microbiota and the host immune system. The hologenome theory of evolution supports this concept and implies that therapeutic strategies aiming to control glycemia should take into account both the gut microbiota and the host immune system. This review discusses the latest evidence regarding the bidirectional impact of the gut microbiota on host immune system crosstalk for the control of metabolic disease, hyperglycemia, and obesity. To avoid redundancies with the literature, we will focus our attention on the intestinal immune system, identifying evidence for the generation of novel therapeutic strategies, which could be based on the control of the translocation of gut bacteria to tissues. Such novel strategies should hamper the role played by gut microbiota dysbiosis on the development of metabolic inflammation. Recent evidence in rodents allows us to conclude that an impaired intestinal immune system characterizes and could be causal in the development of metabolic disease. The fine understanding of the molecular mechanisms should allow for the development of a first line of treatment for metabolic disease and its co-morbidities.}, }
@article {pmid28681143, year = {2018}, author = {van de Water, JAJM and Voolstra, CR and Rottier, C and Cocito, S and Peirano, A and Allemand, D and Ferrier-Pagès, C}, title = {Seasonal Stability in the Microbiomes of Temperate Gorgonians and the Red Coral Corallium rubrum Across the Mediterranean Sea.}, journal = {Microbial ecology}, volume = {75}, number = {1}, pages = {274-288}, doi = {10.1007/s00248-017-1006-y}, pmid = {28681143}, issn = {1432-184X}, abstract = {Populations of key benthic habitat-forming octocoral species have declined significantly in the Mediterranean Sea due to mass mortality events caused by microbial disease outbreaks linked to high summer seawater temperatures. Recently, we showed that the microbial communities of these octocorals are relatively structured; however, our knowledge on the seasonal dynamics of these microbiomes is still limited. To investigate their seasonal stability, we collected four soft gorgonian species (Eunicella singularis, Eunicella cavolini, Eunicella verrucosa and Leptogorgia sarmentosa) and the precious red coral (Corallium rubrum) from two coastal locations with different terrestrial impact levels in the Mediterranean Sea, and used next-generation amplicon sequencing of the 16S rRNA gene. The microbiomes of all soft gorgonian species were dominated by the same 'core microbiome' bacteria belonging to the Endozoicomonas and the Cellvibrionales clade BD1-7, whereas the red coral microbiome was primarily composed of 'core' Spirochaetes, Oceanospirillales ME2 and Parcubacteria. The associations with these bacterial taxa were relatively consistent over time at each location for each octocoral species. However, differences in microbiome composition and seasonal dynamics were observed between locations and could primarily be attributed to locally variant bacteria. Overall, our data provide further evidence of the intricate symbiotic relationships that exist between Mediterranean octocorals and their associated microbes, which are ancient and highly conserved over both space and time, and suggest regulation of the microbiome composition by the host, depending on local conditions.}, }
@article {pmid28679724, year = {2017}, author = {Smith, EG and D'Angelo, C and Sharon, Y and Tchernov, D and Wiedenmann, J}, title = {Acclimatization of symbiotic corals to mesophotic light environments through wavelength transformation by fluorescent protein pigments.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1858}, pages = {}, doi = {10.1098/rspb.2017.0320}, pmid = {28679724}, issn = {1471-2954}, support = {311179//European Research Council/International ; }, mesh = {*Acclimatization ; Animals ; Anthozoa/physiology/*radiation effects ; Coral Reefs ; Dinoflagellida/physiology/*radiation effects ; Fluorescence ; *Light ; *Pigmentation ; Symbiosis ; }, abstract = {The depth distribution of reef-building corals exposes their photosynthetic symbionts of the genus Symbiodinium to extreme gradients in the intensity and spectral quality of the ambient light environment. Characterizing the mechanisms used by the coral holobiont to respond to the low intensity and reduced spectral composition of the light environment in deeper reefs (greater than 20 m) is fundamental to our understanding of the functioning and structure of reefs across depth gradients. Here, we demonstrate that host pigments, specifically photoconvertible red fluorescent proteins (pcRFPs), can promote coral adaptation/acclimatization to deeper-water light environments by transforming the prevalent blue light into orange-red light, which can penetrate deeper within zooxanthellae-containing tissues; this facilitates a more homogeneous distribution of photons across symbiont communities. The ecological importance of pcRFPs in deeper reefs is supported by the increasing proportion of red fluorescent corals with depth (measured down to 45 m) and increased survival of colour morphs with strong expression of pcRFPs in long-term light manipulation experiments. In addition to screening by host pigments from high light intensities in shallow water, the spectral transformation observed in deeper-water corals highlights the importance of GFP-like protein expression as an ecological mechanism to support the functioning of the coral-Symbiodinium association across steep environmental gradients.}, }
@article {pmid28659968, year = {2017}, author = {Sandoval-Motta, S and Aldana, M and Martínez-Romero, E and Frank, A}, title = {The Human Microbiome and the Missing Heritability Problem.}, journal = {Frontiers in genetics}, volume = {8}, number = {}, pages = {80}, doi = {10.3389/fgene.2017.00080}, pmid = {28659968}, issn = {1664-8021}, abstract = {The &quot;missing heritability&quot; problem states that genetic variants in Genome-Wide Association Studies (GWAS) cannot completely explain the heritability of complex traits. Traditionally, the heritability of a phenotype is measured through familial studies using twins, siblings and other close relatives, making assumptions on the genetic similarities between them. When this heritability is compared to the one obtained through GWAS for the same traits, a substantial gap between both measurements arise with genome wide studies reporting significantly smaller values. Several mechanisms for this &quot;missing heritability&quot; have been proposed, such as epigenetics, epistasis, and sequencing depth. However, none of them are able to fully account for this gap in heritability. In this paper we provide evidence that suggests that in order for the phenotypic heritability of human traits to be broadly understood and accounted for, the compositional and functional diversity of the human microbiome must be taken into account. This hypothesis is based on several observations: (A) The composition of the human microbiome is associated with many important traits, including obesity, cancer, and neurological disorders. (B) Our microbiome encodes a second genome with nearly a 100 times more genes than the human genome, and this second genome may act as a rich source of genetic variation and phenotypic plasticity. (C) Human genotypes interact with the composition and structure of our microbiome, but cannot by themselves explain microbial variation. (D) Microbial genetic composition can be strongly influenced by the host's behavior, its environment or by vertical and horizontal transmissions from other hosts. Therefore, genetic similarities assumed in familial studies may cause overestimations of heritability values. We also propose a method that allows the compositional and functional diversity of our microbiome to be incorporated to genome wide association studies.}, }
@article {pmid28659905, year = {2017}, author = {Yang, SH and Tseng, CH and Huang, CR and Chen, CP and Tandon, K and Lee, STM and Chiang, PW and Shiu, JH and Chen, CA and Tang, SL}, title = {Long-Term Survey Is Necessary to Reveal Various Shifts of Microbial Composition in Corals.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {1094}, doi = {10.3389/fmicb.2017.01094}, pmid = {28659905}, issn = {1664-302X}, abstract = {The coral holobiont is the assemblage of coral host and its microbial symbionts, which functions as a unit and is responsive to host species and environmental factors. Although monitoring surveys have been done to determine bacteria associated with coral, none have persisted for >1 year. Therefore, potential variations in minor or dominant community members that occur over extended intervals have not been characterized. In this study, 16S rRNA gene amplicon pyrosequencing was used to investigate the relationship between bacterial communities in healthy Stylophora pistillata in tropical and subtropical Taiwan over 2 years, apparently one of the longest surveys of coral-associated microbes. Dominant bacterial genera in S. pistillata had disparate changes in different geographical setups, whereas the constitution of minor bacteria fluctuated in abundance over time. We concluded that dominant bacteria (Acinetobacter, Propionibacterium, and Pseudomonas) were stable in composition, regardless of seasonal and geographical variations, whereas Endozoicomonas had a geographical preference. In addition, by combining current data with previous studies, we concluded that a minor bacteria symbiont, Ralstonia, was a keystone species in coral. Finally, we concluded that long-term surveys for coral microbial communities were necessary to detect compositional shifts, especially for minor bacterial members in corals.}, }
@article {pmid28654220, year = {2017}, author = {Campisano, A and Albanese, D and Yousaf, S and Pancher, M and Donati, C and Pertot, I}, title = {Temperature drives the assembly of endophytic communities' seasonal succession.}, journal = {Environmental microbiology}, volume = {19}, number = {8}, pages = {3353-3364}, doi = {10.1111/1462-2920.13843}, pmid = {28654220}, issn = {1462-2920}, mesh = {Bradyrhizobium/classification/growth &amp; development/isolation &amp; purification ; Burkholderia/classification/growth &amp; development/isolation &amp; purification ; Endophytes/*classification/*growth &amp; development/isolation &amp; purification ; Mesorhizobium/classification/growth &amp; development/isolation &amp; purification ; *Microbiota ; Plant Roots/*microbiology ; Propionibacterium/classification/growth &amp; development/isolation &amp; purification ; Ralstonia/classification/growth &amp; development/isolation &amp; purification ; Seasons ; Temperature ; Vitis/*microbiology ; }, abstract = {Endophytic microorganisms asymptomatically colonise plant tissues. Exploring the assembly dynamics of bacterial endophytic communities is essential to understand the functioning of the plant holobiont and to optimise their possible use as biopesticides or plant biostimulants. The variation in endophytic communities in above and below-ground organs in Vitis vinifera in the field were studied. To understand the specific effect of temperature on endophytic communities, a separate experiment was set up where grapevine cuttings were grown under controlled conditions at three different temperatures. The findings revealed the succession of endophytic communities over the year. Endophytic communities of roots and stems differ in terms of composition and dynamic response to temperature. Noticeably, compositional differences during the seasons affected bacterial taxa more in stems than in roots, suggesting that roots offer a more stable and less easily perturbed environment. Correlation abundance networks showed that the presence of several taxa (including Bradyrhizobium, Burkholderia, Dyella, Mesorhizobium, Propionibacterium and Ralstonia) is linked in both the field and the greenhouse.}, }
@article {pmid28646902, year = {2017}, author = {Pitlik, SD and Koren, O}, title = {How holobionts get sick-toward a unifying scheme of disease.}, journal = {Microbiome}, volume = {5}, number = {1}, pages = {64}, doi = {10.1186/s40168-017-0281-7}, pmid = {28646902}, issn = {2049-2618}, support = {//CIHR/Canada ; }, mesh = {Animals ; Bacteria/pathogenicity ; Biological Evolution ; *Disease ; Genome ; Host-Pathogen Interactions ; Humans ; *Microbiota ; Plants ; Symbiosis ; }, abstract = {All humans, animals, and plants are holobionts. Holobionts comprise the host and a myriad of interacting microorganisms-the microbiota. The hologenome encompasses the genome of the host plus the composite of all microbial genomes (the microbiome). In health, there is a fine-tuned and resilient equilibrium within the members of the microbiota and between them and the host. This relative stability is maintained by a high level of microbial diversity, a delicate bio-geographic distribution of microorganisms, and a sophisticated and intricate molecular crosstalk among the multiple components of the holobiont. Pathobionts are temporarily benign microbes with the potential, under modified ecosystem conditions, to become key players in disease. Pathobionts may be endogenous, living for prolonged periods of time inside or on the host, or exogenous, invading the host during opportunistic situations. In both cases, the end result is the transformation of the beneficial microbiome into a health-perturbing pathobiome. We hypothesize that probably all diseases of holobionts, acute or chronic, infectious or non-infectious, and regional or systemic, are characterized by a perturbation of the healthy microbiome into a diseased pathobiome.}, }
@article {pmid28625867, year = {2017}, author = {Postler, TS and Ghosh, S}, title = {Understanding the Holobiont: How Microbial Metabolites Affect Human Health and Shape the Immune System.}, journal = {Cell metabolism}, volume = {26}, number = {1}, pages = {110-130}, doi = {10.1016/j.cmet.2017.05.008}, pmid = {28625867}, issn = {1932-7420}, support = {R01 DK102180/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; Bacteria/*metabolism ; *Gastrointestinal Microbiome ; Humans ; Immune System/*metabolism/microbiology ; Inflammation/*metabolism/microbiology ; Inflammatory Bowel Diseases/metabolism/microbiology ; Metabolic Diseases/*metabolism/microbiology ; *Metabolome ; }, abstract = {The human gastrointestinal tract is populated by a diverse, highly mutualistic microbial flora, which is known as the microbiome. Disruptions to the microbiome have been shown to be associated with severe pathologies of the host, including metabolic disease, cancer, and inflammatory bowel disease. Mood and behavior are also susceptible to alterations in the gut microbiota. A particularly striking example of the symbiotic effects of the microbiome is the immune system, whose cells depend critically on a diverse array of microbial metabolites for normal development and behavior. This includes metabolites that are produced by bacteria from dietary components, metabolites that are produced by the host and biochemically modified by gut bacteria, and metabolites that are synthesized de novo by gut microbes. In this review, we highlight the role of the intestinal microbiome in human metabolic and inflammatory diseases and focus in particular on the molecular mechanisms that govern the gut-immune axis.}, }
@article {pmid28624904, year = {2017}, author = {Coelho-Souza, SA and Jenkins, SR and Casarin, A and Baeta-Neves, MH and Salgado, LT and Guimaraes, JRD and Coutinho, R}, title = {The Effect of Light on Bacterial Activity in a Seaweed Holobiont.}, journal = {Microbial ecology}, volume = {74}, number = {4}, pages = {868-876}, doi = {10.1007/s00248-017-0995-x}, pmid = {28624904}, issn = {1432-184X}, mesh = {Anti-Bacterial Agents/*pharmacology ; *Autotrophic Processes ; *Bacterial Physiological Phenomena/drug effects ; *Biofilms/drug effects/growth &amp; development/radiation effects ; Brazil ; Circadian Rhythm ; *Light ; Sargassum/microbiology ; Seasons ; }, abstract = {Holobionts are characterized by the relationship between host and their associated organisms such as the biofilm associated with macroalgae. Considering that light is essential to macroalgae survival, the aim of this study was to verify the effect of light on the heterotrophic activity in biofilms of the brown macroalgae Sargassum furcatum during its growth cycle. Measurements of heterotrophic activity were done under natural light levels at different times during a daily cycle and under an artificial extinction of natural light during the afternoon. We also measured Sargassum primary production under these light levels in the afternoon. Both measurements were done with and without photosynthesis inhibitor and antibiotics. Biofilm composition was mainly represented by bacteria but diatoms, cyanobacteria, and other organisms were also common. When a peak of diatom genera was recorded, the heterotrophic activity of the biofilm was higher. Heterotrophic activity was usually highest during the afternoon and the presence of a photosynthesis inhibitor caused an average reduction of 17% but there was no relationship with Sargassum primary production. These results indicate that autotrophic production in the biofilm was reduced by the inhibitor with consequences on bacterial activity. Heterotrophic activity was mainly bacterial and the antibiotics chloramphenicol and penicillin were more effective than streptomycin. We suggest primary producers in the biofilm are more important to increase bacterial activity than the macroalgae itself because of coherence of the peaks of heterotrophic and autotrophic activity in biofilm during the afternoon and the effects of autotrophic inhibitors on heterotrophic activity.}, }
@article {pmid28601483, year = {2017}, author = {Tripp, EA and Zhang, N and Schneider, H and Huang, Y and Mueller, GM and Hu, Z and Häggblom, M and Bhattacharya, D}, title = {Reshaping Darwin's Tree: Impact of the Symbiome.}, journal = {Trends in ecology &amp; evolution}, volume = {32}, number = {8}, pages = {552-555}, doi = {10.1016/j.tree.2017.05.002}, pmid = {28601483}, issn = {1872-8383}, mesh = {*Biodiversity ; Humans ; *Phylogeny ; }, abstract = {Much of the undescribed biodiversity on Earth is microbial, often in mutualistic or pathogenic associations. Physically associated and coevolving life forms comprise a symbiome. We propose that systematics research can accelerate progress in science by introducing a new framework for phylogenetic analysis of symbiomes, here termed SYMPHY (symbiome phylogenetics).}, }
@article {pmid28572677, year = {2017}, author = {Wright, RM and Kenkel, CD and Dunn, CE and Shilling, EN and Bay, LK and Matz, MV}, title = {Intraspecific differences in molecular stress responses and coral pathobiome contribute to mortality under bacterial challenge in Acropora millepora.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {2609}, doi = {10.1038/s41598-017-02685-1}, pmid = {28572677}, issn = {2045-2322}, abstract = {Disease causes significant coral mortality worldwide; however, factors responsible for intraspecific variation in disease resistance remain unclear. We exposed fragments of eight Acropora millepora colonies (genotypes) to putatively pathogenic bacteria (Vibrio spp.). Genotypes varied from zero to >90% mortality, with bacterial challenge increasing average mortality rates 4-6 fold and shifting the microbiome in favor of stress-associated taxa. Constitutive immunity and subsequent immune and transcriptomic responses to the challenge were more prominent in high-mortality individuals, whereas low-mortality corals remained largely unaffected and maintained expression signatures of a healthier condition (i.e., did not launch a large stress response). Our results suggest that lesions appeared due to changes in the coral pathobiome (multiple bacterial species associated with disease) and general health deterioration after the biotic disturbance, rather than the direct activity of any specific pathogen. If diseases in nature arise because of weaknesses in holobiont physiology, instead of the virulence of any single etiological agent, environmental stressors compromising coral condition might play a larger role in disease outbreaks than is currently thought. To facilitate the diagnosis of compromised individuals, we developed and independently cross-validated a biomarker assay to predict mortality based on genes whose expression in asymptomatic individuals coincides with mortality rates.}, }
@article {pmid28553264, year = {2017}, author = {Carrier, TJ and Reitzel, AM}, title = {The Hologenome Across Environments and the Implications of a Host-Associated Microbial Repertoire.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {802}, doi = {10.3389/fmicb.2017.00802}, pmid = {28553264}, issn = {1664-302X}, abstract = {Our understanding of the diverse interactions between hosts and microbes has grown profoundly over the past two decades and, as a product, has revolutionized our knowledge of the life sciences. Through primarily laboratory experiments, the current framework for holobionts and their respective hologenomes aims to decipher the underpinnings and implications of symbioses between host and microbiome. However, the laboratory setting restricts the full spectrum of host-associated symbionts as compared to those found in nature; thus, limiting the potential for a holistic interpretation of the functional roles the microbiome plays in host biology. When holobionts are studied in nature, associated microbial communities vary considerably between conditions, resulting in more microbial associates as part of the &quot;hologenome&quot; across environments than in either environment alone. We review and synthesize empirical evidence suggesting that hosts may associate with a larger microbial network that, in part, corresponds to experiencing diverse environmental conditions. To conceptualize the interactions between host and microbiome in an ecological context, we suggest the &quot;host-associated microbial repertoire,&quot; which is the sum of microbial species a host may associate with over the course of its life-history under all encountered environmental circumstances. Furthermore, using examples from both terrestrial and marine ecosystems, we discuss how this concept may be used as a framework to compare the ability of the holobiont to acclimate and adapt to environmental variation, and propose three &quot;signatures&quot; of the concept.}, }
@article {pmid28549621, year = {2017}, author = {Lemanceau, P and Blouin, M and Muller, D and Moënne-Loccoz, Y}, title = {Let the Core Microbiota Be Functional.}, journal = {Trends in plant science}, volume = {22}, number = {7}, pages = {583-595}, doi = {10.1016/j.tplants.2017.04.008}, pmid = {28549621}, issn = {1878-4372}, mesh = {Plants/*microbiology ; *Rhizosphere ; Soil Microbiology ; }, abstract = {The microbial community that is systematically associated with a given host plant is called the core microbiota. The definition of the core microbiota was so far based on its taxonomic composition, but we argue that it should also be based on its functions. This so-called functional core microbiota encompasses microbial vehicles carrying replicators (genes) with essential functions for holobiont (i.e., plant plus microbiota) fitness. It builds up from enhanced horizontal transfers of replicators as well as from ecological enrichment of their vehicles. The transmission pathways of this functional core microbiota vary over plant generations according to environmental constraints and its added value for holobiont fitness.}, }
@article {pmid28546553, year = {2017}, author = {Smith, EG and Vaughan, GO and Ketchum, RN and McParland, D and Burt, JA}, title = {Symbiont community stability through severe coral bleaching in a thermally extreme lagoon.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {2428}, doi = {10.1038/s41598-017-01569-8}, pmid = {28546553}, issn = {2045-2322}, abstract = {Coral reefs are threatened by climate change as coral-algal symbioses are currently living close to their upper thermal limits. The resilience of the algal partner plays a key role in determining the thermal tolerance of the coral holobiont and therefore, understanding the acclimatory limits of present day coral-algal symbioses is fundamental to forecasting corals' responses to climate change. This study characterised the symbiont community in a highly variable and thermally extreme (Max = 37.5 °C, Min = 16.8 °C) lagoon located in the southern Persian/Arabian Gulf using next generation sequencing of ITS2 amplicons. Despite experiencing extreme temperatures, severe bleaching and many factors that would be expected to promote the presence of, or transition to clade D dominance, the symbiont communities of the lagoon remain dominated by the C3 variant, Symbiodinium thermophilum. The stability of this symbiosis across multiple genera with different means of symbiont transmission highlights the importance of Symbiodinium thermophilum for corals living at the acclimatory limits of modern day corals. Corals in this extreme environment did not undergo adaptive bleaching, suggesting they are living at the edge of their acclimatory potential and that this valuable source of thermally tolerant genotypes may be lost in the near future under climate change.}, }
@article {pmid28534879, year = {2017}, author = {Frischkorn, KR and Rouco, M and Van Mooy, BAS and Dyhrman, ST}, title = {Epibionts dominate metabolic functional potential of Trichodesmium colonies from the oligotrophic ocean.}, journal = {The ISME journal}, volume = {11}, number = {9}, pages = {2090-2101}, doi = {10.1038/ismej.2017.74}, pmid = {28534879}, issn = {1751-7370}, mesh = {Nitrogen/metabolism ; Nitrogen Fixation ; Oceans and Seas ; Phylogeny ; Seawater/*microbiology ; Trichodesmium/classification/genetics/*isolation &amp; purification/metabolism ; }, abstract = {Trichodesmium is a genus of marine diazotrophic colonial cyanobacteria that exerts a profound influence on global biogeochemistry, by injecting 'new' nitrogen into the low nutrient systems where it occurs. Colonies of Trichodesmium ubiquitously contain a diverse assemblage of epibiotic microorganisms, constituting a microbiome on the Trichodesmium host. Metagenome sequences from Trichodesmium colonies were analyzed along a resource gradient in the western North Atlantic to examine microbiome community structure, functional diversity and metabolic contributions to the holobiont. Here we demonstrate the presence of a core Trichodesmium microbiome that is modulated to suit different ocean regions, and contributes over 10 times the metabolic potential of Trichodesmium to the holobiont. Given the ubiquitous nature of epibionts on colonies, the substantial functional diversity within the microbiome is likely an integral facet of Trichodesmium physiological ecology across the oligotrophic oceans where this biogeochemically significant diazotroph thrives.}, }
@article {pmid28533520, year = {2017}, author = {Strand, R and Whalan, S and Webster, NS and Kutti, T and Fang, JKH and Luter, HM and Bannister, RJ}, title = {The response of a boreal deep-sea sponge holobiont to acute thermal stress.}, journal = {Scientific reports}, volume = {7}, number = {1}, pages = {1660}, doi = {10.1038/s41598-017-01091-x}, pmid = {28533520}, issn = {2045-2322}, abstract = {Effects of elevated seawater temperatures on deep-water benthos has been poorly studied, despite reports of increased seawater temperature (up to 4 °C over 24 hrs) coinciding with mass mortality events of the sponge Geodia barretti at Tisler Reef, Norway. While the mechanisms driving these mortality events are unclear, manipulative laboratory experiments were conducted to quantify the effects of elevated temperature (up to 5 °C, above ambient levels) on the ecophysiology (respiration rate, nutrient uptake, cellular integrity and sponge microbiome) of G. barretti. No visible signs of stress (tissue necrosis or discolouration) were evident across experimental treatments; however, significant interactive effects of time and treatment on respiration, nutrient production and cellular stress were detected. Respiration rates and nitrogen effluxes doubled in responses to elevated temperatures (11 °C &amp; 12 °C) compared to control temperatures (7 °C). Cellular stress, as measured through lysosomal destabilisation, was 2-5 times higher at elevated temperatures than for control temperatures. However, the microbiome of G. barretti remained stable throughout the experiment, irrespective of temperature treatment. Mortality was not evident and respiration rates returned to pre-experimental levels during recovery. These results suggest other environmental processes, either alone or in combination with elevated temperature, contributed to the mortality of G. barretti at Tisler reef.}, }
@article {pmid28509908, year = {2017}, author = {Webster, NS and Reusch, TBH}, title = {Microbial contributions to the persistence of coral reefs.}, journal = {The ISME journal}, volume = {11}, number = {10}, pages = {2167-2174}, doi = {10.1038/ismej.2017.66}, pmid = {28509908}, issn = {1751-7370}, mesh = {Acclimatization ; Animals ; Anthozoa/*microbiology/physiology ; *Coral Reefs ; Evolution, Molecular ; Gene Transfer, Horizontal ; *Microbiota/genetics ; }, abstract = {On contemplating the adaptive capacity of reef organisms to a rapidly changing environment, the microbiome offers significant and greatly unrecognised potential. Microbial symbionts contribute to the physiology, development, immunity and behaviour of their hosts, and can respond very rapidly to changing environmental conditions, providing a powerful mechanism for acclimatisation and also possibly rapid evolution of coral reef holobionts. Environmentally acquired fluctuations in the microbiome can have significant functional consequences for the holobiont phenotype upon which selection can act. Environmentally induced changes in microbial abundance may be analogous to host gene duplication, symbiont switching / shuffling as a result of environmental change can either remove or introduce raw genetic material into the holobiont; and horizontal gene transfer can facilitate rapid evolution within microbial strains. Vertical transmission of symbionts is a key feature of many reef holobionts and this would enable environmentally acquired microbial traits to be faithfully passed to future generations, ultimately facilitating microbiome-mediated transgenerational acclimatisation (MMTA) and potentially even adaptation of reef species in a rapidly changing climate. In this commentary, we highlight the capacity and mechanisms for MMTA in reef species, propose a modified Price equation as a framework for assessing MMTA and recommend future areas of research to better understand how microorganisms contribute to the transgenerational acclimatisation of reef organisms, which is essential if we are to reliably predict the consequences of global change for reef ecosystems.}, }
@article {pmid28491055, year = {2017}, author = {Xia, X and Gurr, GM and Vasseur, L and Zheng, D and Zhong, H and Qin, B and Lin, J and Wang, Y and Song, F and Li, Y and Lin, H and You, M}, title = {Metagenomic Sequencing of Diamondback Moth Gut Microbiome Unveils Key Holobiont Adaptations for Herbivory.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {663}, doi = {10.3389/fmicb.2017.00663}, pmid = {28491055}, issn = {1664-302X}, abstract = {Herbivore specialists adapt to feed on a specific group of host plants by evolving various mechanisms to respond to plant defenses. Insects also possess complex gut microbiotas but their potential role in adaptation is poorly understood. Our previous study of the genome of diamondback moth, Plutella xylostella, revealed an intrinsic capacity to detoxify plant defense compounds, which is an important factor in its success as a pest. Here we expand on that work with a complete taxonomic and functional profile of the P. xylostella gut microbiota obtained by metagenomic sequencing. Gene enrichment in the metagenome, accompanied by functional identification, revealed an important role of specific gut bacteria in the breakdown of plant cell walls, detoxification of plant phenolics, and synthesis of amino acids. Microbes participating in these pathways mainly belonged to three highly abundant bacteria: Enterobacter cloacae, Enterobacter asburiae, and Carnobacterium maltaromaticum. Results show that while the gut microbial community may be complex, a small number of functionally active species can be disproportionally important. The presence of specific enzymes in the microbiota community, such as supporting amino acid synthesis, digestion and detoxification functions, demonstrates the beneficial interactions between P. xylostella and its gut microbiota. These interactions can be potential targets for manipulation to provide novel pest management approaches.}, }
@article {pmid28486655, year = {2017}, author = {Silveira, CB and Cavalcanti, GS and Walter, JM and Silva-Lima, AW and Dinsdale, EA and Bourne, DG and Thompson, CC and Thompson, FL}, title = {Microbial processes driving coral reef organic carbon flow.}, journal = {FEMS microbiology reviews}, volume = {41}, number = {4}, pages = {575-595}, doi = {10.1093/femsre/fux018}, pmid = {28486655}, issn = {1574-6976}, mesh = {Biodiversity ; Carbon/*metabolism ; *Coral Reefs ; Ecosystem ; Microbiota/*physiology ; Mucus/microbiology ; *Water Microbiology ; }, abstract = {Coral reefs are one of the most productive ecosystems on the planet, with primary production rates compared to that of rain forests. Benthic organisms release 10-50% of their gross organic production as mucus that stimulates heterotrophic microbial metabolism in the water column. As a result, coral reef microbes grow up to 50 times faster than open ocean communities. Anthropogenic disturbances cause once coral-dominated reefs to become dominated by fleshy organisms, with several outcomes for trophic relationships. Here we review microbial processes implicated in organic carbon flux in coral reefs displaying species phase shifts. The first section presents microbial players and interactions within the coral holobiont that contribute to reef carbon flow. In the second section, we identify four ecosystem-level microbial features that directly respond to benthic species phase shifts: community composition, biomass, metabolism and viral predation. The third section discusses the significance of microbial consumption of benthic organic matter to reef trophic relationships. In the fourth section, we propose that the 'microbial phase shifts' discussed here are conducive to lower resilience, facilitating the transition to new degradation states in coral reefs.}, }
@article {pmid28484479, year = {2017}, author = {Smith, DL and Gravel, V and Yergeau, E}, title = {Editorial: Signaling in the Phytomicrobiome.}, journal = {Frontiers in plant science}, volume = {8}, number = {}, pages = {611}, doi = {10.3389/fpls.2017.00611}, pmid = {28484479}, issn = {1664-462X}, }
@article {pmid28473829, year = {2017}, author = {Romano, M}, title = {Gut Microbiota as a Trigger of Accelerated Directional Adaptive Evolution: Acquisition of Herbivory in the Context of Extracellular Vesicles, MicroRNAs and Inter-Kingdom Crosstalk.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {721}, doi = {10.3389/fmicb.2017.00721}, pmid = {28473829}, issn = {1664-302X}, abstract = {According to a traditional view, the specific diet in vertebrates is one of the key factors structuring the composition of the gut microbiota. In this interpretation, the microbiota assumes a subordinate position, where the larger host shapes, through evolution and its fitness, the taxonomical composition of the hosted microbiota. The present contribution shows how the evolution of herbivory, framed within the new concept of holobiont, the possibility of inter-kingdom crosstalk and its epigenetic effects, could pave the way to a completely reversed interpretation: instead of being passively shaped, the microbiota can mold and shape the general host body structure to increase its fitness. Central elements to consider in this context are the inter-kingdom crosstalk, the possibility of transporting RNAs through nanovesicles in feces from parents to offspring, and the activation of epigenetic processes passed on vertically from generation to generation. The new hypothesis is that the gut microbiota could play a great role in the macroevolutionary dynamics of herbivorous vertebrates, causing directly through host-microbiota dialog of epigenetic nature (i.e., methylation, histone acetylation, etc.), major changes in the organisms phenotype. The vertical exchange of the same microbial communities from parents to offspring, the interaction of these microbes with fairly uniform genotypes, and the socially restricted groups where these processes take place, could all explain the reasons why herbivory has appeared several time (and independently) during the evolution of vertebrates. The new interpretation could also represent a key factor in understanding the convergent evolution of analogous body structures in very distant lineages.}, }
@article {pmid28464532, year = {2017}, author = {Sogin, EM and Putnam, HM and Nelson, CE and Anderson, P and Gates, RD}, title = {Correspondence of coral holobiont metabolome with symbiotic bacteria, archaea and Symbiodinium communities.}, journal = {Environmental microbiology reports}, volume = {9}, number = {3}, pages = {310-315}, doi = {10.1111/1758-2229.12541}, pmid = {28464532}, issn = {1758-2229}, mesh = {Alveolata/*growth &amp; development/metabolism ; Animals ; Anthozoa/*microbiology/*parasitology ; Archaea/classification/*growth &amp; development/metabolism ; Biodiversity ; Coral Reefs ; Gammaproteobacteria/*growth &amp; development/metabolism ; Metabolome/physiology ; Symbiosis/*physiology ; Vibrionaceae/*growth &amp; development/metabolism ; }, abstract = {Microbial symbiotic partners, such as those associated with Scleractinian corals, mediate biochemical transformations that influence host performance and survival. While evidence suggests microbial community composition partly accounts for differences in coral physiology, how these symbionts affect metabolic pathways remains underexplored. We aimed to assess functional implications of variation among coral-associated microbial partners in hospite. To this end, we characterized and compared metabolomic profiles and microbial community composition from nine reef-building coral species. These data demonstrate metabolite profiles and microbial communities are species-specific and are correlated to one another. Using Porites spp. as a case study, we present evidence that the relative abundance of different sub-clades of Symbiodinium and bacterial/archaeal families are linked to positive and negative metabolomic signatures. Our data suggest that while some microbial partners benefit the union, others are more opportunistic with potential detriment to the host. Consequently, coral partner choice likely influences cellular metabolic activities and, therefore, holobiont nutrition.}, }
@article {pmid28447372, year = {2017}, author = {Chakravarti, LJ and Beltran, VH and van Oppen, MJH}, title = {Rapid thermal adaptation in photosymbionts of reef-building corals.}, journal = {Global change biology}, volume = {23}, number = {11}, pages = {4675-4688}, doi = {10.1111/gcb.13702}, pmid = {28447372}, issn = {1365-2486}, abstract = {Climate warming is occurring at a rate not experienced by life on Earth for 10 s of millions of years, and it is unknown whether the coral-dinoflagellate (Symbiodinium spp.) symbiosis can evolve fast enough to ensure coral reef persistence. Coral thermal tolerance is partly dependent on the Symbiodinium hosted. Therefore, directed laboratory evolution in Symbiodinium has been proposed as a strategy to enhance coral holobiont thermal tolerance. Using a reciprocal transplant design, we show that the upper temperature tolerance and temperature tolerance range of Symbiodinium C1 increased after ~80 asexual generations (2.5 years) of laboratory thermal selection. Relative to wild-type cells, selected cells showed superior photophysiological performance and growth rate at 31°C in vitro, and performed no worse at 27°C; they also had lower levels of extracellular reactive oxygen species (exROS). In contrast, wild-type cells were unable to photosynthesise or grow at 31°C and produced up to 17 times more exROS. In symbiosis, the increased thermal tolerance acquired ex hospite was less apparent. In recruits of two of three species tested, those harbouring selected cells showed no difference in growth between the 27 and 31°C treatments, and a trend of positive growth at both temperatures. Recruits that were inoculated with wild-type cells, however, showed a significant difference in growth rates between the 27 and 31°C treatments, with a negative growth trend at 31°C. There were no significant differences in the rate and severity of bleaching in coral recruits harbouring wild-type or selected cells. Our findings highlight the need for additional Symbiodinium genotypes to be tested with this assisted evolution approach. Deciphering the genetic basis of enhanced thermal tolerance in Symbiodinium and the cause behind its limited transference to the coral holobiont in this genotype of Symbiodinium C1 are important next steps for developing methods that aim to increase coral bleaching tolerance.}, }
@article {pmid28446691, year = {2017}, author = {Enríquez, S and Méndez, ER and Hoegh-Guldberg, O and Iglesias-Prieto, R}, title = {Key functional role of the optical properties of coral skeletons in coral ecology and evolution.}, journal = {Proceedings. Biological sciences}, volume = {284}, number = {1853}, pages = {}, doi = {10.1098/rspb.2016.1667}, pmid = {28446691}, issn = {1471-2954}, mesh = {Animals ; Anthozoa/*physiology ; *Coral Reefs ; Ecology ; *Light ; Optical Phenomena ; Symbiosis ; }, abstract = {Multiple scattering of light on coral skeleton enhances light absorption efficiency of coral symbionts and plays a key role in the regulation of their internal diffuse light field. To understand the dependence of this enhancement on skeleton meso- and macrostructure, we analysed the scattering abilities of naked coral skeletons for 74 Indo-Pacific species. Sensitive morphotypes to thermal and light stress, flat-extraplanate and branching corals, showed the most efficient structures, while massive-robust species were less efficient. The lowest light-enhancing scattering abilities were found for the most primitive colonial growth form: phaceloid. Accordingly, the development of highly efficient light-collecting structures versus the selection of less efficient but more robust holobionts to cope with light stress may constitute a trade-off in the evolution of modern symbiotic scleractinian corals, characterizing two successful adaptive solutions. The coincidence of the most important structural modifications with epitheca decline supports the importance of the enhancement of light transmission across coral skeleton in modern scleractinian diversification, and the central role of these symbioses in the design and optimization of coral skeleton. Furthermore, the same ability that lies at the heart of the success of symbiotic corals as coral-reef-builders can also explain the 'Achilles's heel' of these symbioses in a warming ocean.}, }
@article {pmid28437665, year = {2017}, author = {Carvalhais, LC and Schenk, PM and Dennis, PG}, title = {Jasmonic acid signalling and the plant holobiont.}, journal = {Current opinion in microbiology}, volume = {37}, number = {}, pages = {42-47}, doi = {10.1016/j.mib.2017.03.009}, pmid = {28437665}, issn = {1879-0364}, mesh = {Cyclopentanes/*metabolism ; *Microbiota ; Oxylipins/*metabolism ; Plant Growth Regulators/*metabolism ; Plants/*metabolism/*microbiology ; *Signal Transduction ; }, abstract = {The plant holobiont - which is the plant and its associated microbiome - is increasingly viewed as an evolving entity. Some interacting microbes that compose the microbiome assist plants in combating pathogens and herbivorous insects. However, knowledge of the factors that influence the microbiome in the context of defence signalling pathways is still in its infancy. Recent research reported that changes in jasmonic acid (JA) and salicylic acid signalling affects the root microbiome of Arabidopsis thaliana. This review aims to present the hypothesis that the JA pathway represents a novel mechanism for microbiome engineering for improved holobiont fitness in agricultural systems.}, }
@article {pmid28431245, year = {2017}, author = {Scott, TA and Quintaneiro, LM and Norvaisas, P and Lui, PP and Wilson, MP and Leung, KY and Herrera-Dominguez, L and Sudiwala, S and Pessia, A and Clayton, PT and Bryson, K and Velagapudi, V and Mills, PB and Typas, A and Greene, NDE and Cabreiro, F}, title = {Host-Microbe Co-metabolism Dictates Cancer Drug Efficacy in C. elegans.}, journal = {Cell}, volume = {169}, number = {3}, pages = {442-456.e18}, doi = {10.1016/j.cell.2017.03.040}, pmid = {28431245}, issn = {1097-4172}, mesh = {Animals ; Antineoplastic Agents/*metabolism ; Autophagy ; Caenorhabditis elegans ; Cell Death ; Colorectal Neoplasms/drug therapy ; Diet ; Escherichia coli/enzymology/genetics/*metabolism ; Fluorouracil/*metabolism ; *Gastrointestinal Microbiome ; Humans ; Models, Animal ; Pentosyltransferases/genetics ; }, abstract = {Fluoropyrimidines are the first-line treatment for colorectal cancer, but their efficacy is highly variable between patients. We queried whether gut microbes, a known source of inter-individual variability, impacted drug efficacy. Combining two tractable genetic models, the bacterium E. coli and the nematode C. elegans, we performed three-way high-throughput screens that unraveled the complexity underlying host-microbe-drug interactions. We report that microbes can bolster or suppress the effects of fluoropyrimidines through metabolic drug interconversion involving bacterial vitamin B6, B9, and ribonucleotide metabolism. Also, disturbances in bacterial deoxynucleotide pools amplify 5-FU-induced autophagy and cell death in host cells, an effect regulated by the nucleoside diphosphate kinase ndk-1. Our data suggest a two-way bacterial mediation of fluoropyrimidine effects on host metabolism, which contributes to drug efficacy. These findings highlight the potential therapeutic power of manipulating intestinal microbiota to ensure host metabolic health and treat disease.}, }
@article {pmid28430944, year = {2017}, author = {Berg, G and Köberl, M and Rybakova, D and Müller, H and Grosch, R and Smalla, K}, title = {Plant microbial diversity is suggested as the key to future biocontrol and health trends.}, journal = {FEMS microbiology ecology}, volume = {93}, number = {5}, pages = {}, doi = {10.1093/femsec/fix050}, pmid = {28430944}, issn = {1574-6941}, support = {J 3638//Austrian Science Fund FWF/Austria ; T 847//Austrian Science Fund FWF/Austria ; }, mesh = {Biodiversity ; Biological Control Agents ; Ecosystem ; Microbiota/*physiology ; Plant Development ; Plant Diseases/*microbiology ; Plants/*microbiology ; Symbiosis/*physiology ; Volatile Organic Compounds/metabolism ; }, abstract = {The microbiome of plants plays a crucial role in both plant and ecosystem health. Rapid advances in multi-omics tools are dramatically increasing access to the plant microbiome and consequently to the identification of its links with diseases and to the control of those diseases. Recent insights reveal a close, often symbiotic relationship between microorganisms and plants. Microorganisms can stimulate germination and plant growth, prevent diseases, and promote stress resistance and general fitness. Plants and their associated microorganisms form a holobiont and have to be considered as co-evolved species assemblages consisting of bacterial, archaeal and diverse eukaryotic species. The beneficial interplay of the host and its microbiome is responsible for maintaining the health of the holobiont, while diseases are often correlated with microbial dysbioses. Microbial diversity was identified as a key factor in preventing diseases and can be implemented as a biomarker in plant protection strategies. Targeted and predictive biocontrol approaches are possible by developing microbiome-based solutions. Moreover, combined breeding and biocontrol strategies maintaining diversity and ecosystem health are required. The analysis of plant microbiome data has brought about a paradigm shift in our understanding of its role in health and disease and has substantial consequences for biocontrol and health issues.}, }
@article {pmid28429531, year = {2017}, author = {Pogoreutz, C and Rädecker, N and Cárdenas, A and Gärdes, A and Voolstra, CR and Wild, C}, title = {Sugar enrichment provides evidence for a role of nitrogen fixation in coral bleaching.}, journal = {Global change biology}, volume = {23}, number = {9}, pages = {3838-3848}, doi = {10.1111/gcb.13695}, pmid = {28429531}, issn = {1365-2486}, mesh = {Animals ; *Anthozoa ; Coral Reefs ; Dinoflagellida ; *Nitrogen Fixation ; Symbiosis ; }, abstract = {The disruption of the coral-algae symbiosis (coral bleaching) due to rising sea surface temperatures has become an unprecedented global threat to coral reefs. Despite decades of research, our ability to manage mass bleaching events remains hampered by an incomplete mechanistic understanding of the processes involved. In this study, we induced a coral bleaching phenotype in the absence of heat and light stress by adding sugars. The sugar addition resulted in coral symbiotic breakdown accompanied by a fourfold increase of coral-associated microbial nitrogen fixation. Concomitantly, increased N:P ratios by the coral host and algal symbionts suggest excess availability of nitrogen and a disruption of the nitrogen limitation within the coral holobiont. As nitrogen fixation is similarly stimulated in ocean warming scenarios, here we propose a refined coral bleaching model integrating the cascading effects of stimulated microbial nitrogen fixation. This model highlights the putative role of nitrogen-fixing microbes in coral holobiont functioning and breakdown.}, }
@article {pmid28425179, year = {2017}, author = {Gajigan, AP and Diaz, LA and Conaco, C}, title = {Resilience of the prokaryotic microbial community of Acropora digitifera to elevated temperature.}, journal = {MicrobiologyOpen}, volume = {6}, number = {4}, pages = {}, doi = {10.1002/mbo3.478}, pmid = {28425179}, issn = {2045-8827}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/*classification/genetics/*radiation effects ; Biota/*radiation effects ; Cluster Analysis ; DNA, Archaeal/chemistry/genetics ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; Metagenome ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Temperature ; }, abstract = {The coral is a holobiont formed by the close interaction between the coral animal and a diverse community of microorganisms, including dinoflagellates, bacteria, archaea, fungi, and viruses. The prokaryotic symbionts of corals are important for host fitness but are also highly sensitive to changes in the environment. In this study, we used 16S ribosomal RNA (rRNA) sequencing to examine the response of the microbial community associated with the coral, Acropora digitifera, to elevated temperature. The A. digitifera microbial community is dominated by operational taxonomic unit (OTUs) affiliated with classes Alphaproteobacteria and Gammaproteobacteria. The prokaryotic community in the coral tissue is distinct from that of the mucus and the surrounding seawater. Remarkably, the overall microbial community structure of A. digitifera remained stable for 10 days of continuous exptosure at 32°C compared to corals maintained at 27°C. However, the elevated temperature regime resulted in a decrease in the abundance of OTUs affiliated with certain groups of bacteria, such as order Rhodobacterales. On the other hand, some OTUs affiliated with the orders Alteromonadales, Vibrionales, and Flavobacteriales, which are often associated with diseased and stressed corals, increased in abundance. Thus, while the A. digitifera bacterial community structure appears resilient to higher temperature, prolonged exposure and intensified stress results in changes in the abundance of specific microbial community members that may affect the overall metabolic state and health of the coral holobiont.}, }
@article {pmid28410570, year = {2017}, author = {Valadez-Cano, C and Olivares-Hernández, R and Resendis-Antonio, O and DeLuna, A and Delaye, L}, title = {Natural selection drove metabolic specialization of the chromatophore in Paulinella chromatophora.}, journal = {BMC evolutionary biology}, volume = {17}, number = {1}, pages = {99}, doi = {10.1186/s12862-017-0947-6}, pmid = {28410570}, issn = {1471-2148}, mesh = {Biological Evolution ; Cercozoa/*cytology/genetics/*physiology ; Computer Simulation ; Cyanobacteria/genetics/*physiology ; Hexoses/metabolism ; Selection, Genetic ; Symbiosis ; Synechococcus/cytology/metabolism ; }, abstract = {BACKGROUND: Genome degradation of host-restricted mutualistic endosymbionts has been attributed to inactivating mutations and genetic drift while genes coding for host-relevant functions are conserved by purifying selection. Unlike their free-living relatives, the metabolism of mutualistic endosymbionts and endosymbiont-originated organelles is specialized in the production of metabolites which are released to the host. This specialization suggests that natural selection crafted these metabolic adaptations. In this work, we analyzed the evolution of the metabolism of the chromatophore of Paulinella chromatophora by in silico modeling. We asked whether genome reduction is driven by metabolic engineering strategies resulted from the interaction with the host. As its widely known, the loss of enzyme coding genes leads to metabolic network restructuring sometimes improving the production rates. In this case, the production rate of reduced-carbon in the metabolism of the chromatophore.<br><br>RESULTS: We reconstructed the metabolic networks of the chromatophore of P. chromatophora CCAC 0185 and a close free-living relative, the cyanobacterium Synechococcus sp. WH 5701. We found that the evolution of free-living to host-restricted lifestyle rendered a fragile metabolic network where >80% of genes in the chromatophore are essential for metabolic functionality. Despite the lack of experimental information, the metabolic reconstruction of the chromatophore suggests that the host provides several metabolites to the endosymbiont. By using these metabolites as intracellular conditions, in silico simulations of genome evolution by gene lose recover with 77% accuracy the actual metabolic gene content of the chromatophore. Also, the metabolic model of the chromatophore allowed us to predict by flux balance analysis a maximum rate of reduced-carbon released by the endosymbiont to the host. By inspecting the central metabolism of the chromatophore and the free-living cyanobacteria we found that by improvements in the gluconeogenic pathway the metabolism of the endosymbiont uses more efficiently the carbon source for reduced-carbon production. In addition, our in silico simulations of the evolutionary process leading to the reduced metabolic network of the chromatophore showed that the predicted rate of released reduced-carbon is obtained in less than 5% of the times under a process guided by random gene deletion and genetic drift. We interpret previous findings as evidence that natural selection at holobiont level shaped the rate at which reduced-carbon is exported to the host. Finally, our model also predicts that the ABC phosphate transporter (pstSACB) which is conserved in the genome of the chromatophore of P. chromatophora strain CCAC 0185 is a necessary component to release reduced-carbon molecules to the host.<br><br>CONCLUSION: Our evolutionary analysis suggests that in the case of Paulinella chromatophora natural selection at the holobiont level played a prominent role in shaping the metabolic specialization of the chromatophore. We propose that natural selection acted as a &quot;metabolic engineer&quot; by favoring metabolic restructurings that led to an increased release of reduced-carbon to the host.}, }
@article {pmid28404738, year = {2017}, author = {Galla, S and Chakraborty, S and Mell, B and Vijay-Kumar, M and Joe, B}, title = {Microbiotal-Host Interactions and Hypertension.}, journal = {Physiology (Bethesda, Md.)}, volume = {32}, number = {3}, pages = {224-233}, doi = {10.1152/physiol.00003.2017}, pmid = {28404738}, issn = {1548-9221}, mesh = {Animals ; Humans ; Hypertension/*genetics/*microbiology ; *Metagenome ; Mice ; *Microbiota ; }, abstract = {Hypertension, or elevated blood pressure (BP), has been extensively researched over decades and clearly demonstrated to be caused due to a combination of host genetic and environmental factors. Although much research remains to be conducted to pin-point the precise genetic elements on the host genome that control BP, new lines of evidence are emerging to indicate that, besides the host genome, the genomes of all indigenous commensal micro-organisms, collectively referred to as the microbial metagenome or microbiome, are important, but largely understudied, determinants of BP. Unlike the rigid host genome, the microbiome or the &quot;second genome&quot; can be altered by diet or microbiotal transplantation in the host. This possibility is attractive from the perspective of exploiting the microbiotal composition for clinical management of inherited hypertension. Thus, focusing on the limited current literature supporting a role for the microbiome in BP regulation, this review highlights the need to further explore the role of the co-existence of host and the microbiota as an organized biological unit called the &quot;holobiont&quot; in the context of BP regulation.}, }
@article {pmid28366817, year = {2017}, author = {Forsman, ZH and Knapp, ISS and Tisthammer, K and Eaton, DAR and Belcaid, M and Toonen, RJ}, title = {Coral hybridization or phenotypic variation? Genomic data reveal gene flow between Porites lobata and P. Compressa.}, journal = {Molecular phylogenetics and evolution}, volume = {111}, number = {}, pages = {132-148}, doi = {10.1016/j.ympev.2017.03.023}, pmid = {28366817}, issn = {1095-9513}, mesh = {Animals ; Anthozoa/*genetics ; Gene Flow/*genetics ; Genome, Mitochondrial ; Genomics/*methods ; Geography ; Hawaii ; *Hybridization, Genetic ; Likelihood Functions ; Phenotype ; Phylogeny ; Polymorphism, Single Nucleotide/genetics ; Principal Component Analysis ; Sequence Alignment ; Species Specificity ; }, abstract = {Major gaps remain in our understanding of the ecology, evolution, biodiversity, biogeography, extinction risk, and adaptive potential of reef building corals. One of the central challenges remains that there are few informative genetic markers for studying boundaries between species, and variation within species. Reduced representation sequencing approaches, such as RADseq (Restriction site Associated DNA sequencing) have great potential for resolving such relationships. However, it is necessary to identify loci in order to make inferences for endosymbiotic organisms such as corals. Here, we examined twenty-one coral holobiont ezRAD libraries from Hawai'i, focusing on P. lobata and P. compressa, two species with contrasting morphology and habitat preference that previous studies have not resolved. We used a combination of de novo assembly and reference mapping approaches to identify and compare loci: we used reference mapping to extract and compare nearly complete mitochondrial genomes, ribosomal arrays, and histone genes. We used de novo clustering and phylogenomic methods to compare the complete holobiont data set with coral and symbiont subsets that map to transcriptomic data. In addition, we used reference assemblies to examine genetic structure from SNPs (Single Nucleotide Polymorphisms). All approaches resolved outgroup taxa but failed to resolve P. lobata and P. compressa as distinct, with mito-nuclear discordance and shared mitochondrial haplotypes within the species complex. The holobiont and 'coral transcriptomic' datasets were highly concordant, revealing stronger genetic structure between sites than between coral morphospecies. These results suggest that either branching morphology is a polymorphic trait, or that these species frequently hybridize. This study provides examples of several approaches to acquire, identify, and compare loci across metagenomic samples such as the coral holobiont while providing insights into the nature of coral variability.}, }
@article {pmid28326066, year = {2017}, author = {Peixoto, RS and Rosado, PM and Leite, DC and Rosado, AS and Bourne, DG}, title = {Beneficial Microorganisms for Corals (BMC): Proposed Mechanisms for Coral Health and Resilience.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {341}, doi = {10.3389/fmicb.2017.00341}, pmid = {28326066}, issn = {1664-302X}, abstract = {The symbiotic association between the coral animal and its endosymbiotic dinoflagellate partner Symbiodinium is central to the success of corals. However, an array of other microorganisms associated with coral (i.e., Bacteria, Archaea, Fungi, and viruses) have a complex and intricate role in maintaining homeostasis between corals and Symbiodinium. Corals are sensitive to shifts in the surrounding environmental conditions. One of the most widely reported responses of coral to stressful environmental conditions is bleaching. During this event, corals expel Symbiodinium cells from their gastrodermal tissues upon experiencing extended seawater temperatures above their thermal threshold. An array of other environmental stressors can also destabilize the coral microbiome, resulting in compromised health of the host, which may include disease and mortality in the worst scenario. However, the exact mechanisms by which the coral microbiome supports coral health and increases resilience are poorly understood. Earlier studies of coral microbiology proposed a coral probiotic hypothesis, wherein a dynamic relationship exists between corals and their symbiotic microorganisms, selecting for the coral holobiont that is best suited for the prevailing environmental conditions. Here, we discuss the microbial-host relationships within the coral holobiont, along with their potential roles in maintaining coral health. We propose the term BMC (Beneficial Microorganisms for Corals) to define (specific) symbionts that promote coral health. This term and concept are analogous to the term Plant Growth Promoting Rhizosphere (PGPR), which has been widely explored and manipulated in the agricultural industry for microorganisms that inhabit the rhizosphere and directly or indirectly promote plant growth and development through the production of regulatory signals, antibiotics and nutrients. Additionally, we propose and discuss the potential mechanisms of the effects of BMC on corals, suggesting strategies for the use of this knowledge to manipulate the microbiome, reversing dysbiosis to restore and protect coral reefs. This may include developing and using BMC consortia as environmental &quot;probiotics&quot; to improve coral resistance after bleaching events and/or the use of BMC with other strategies such as human-assisted acclimation/adaption to shifting environmental conditions.}, }
@article {pmid28302492, year = {2017}, author = {O'Malley, MA}, title = {From endosymbiosis to holobionts: Evaluating a conceptual legacy.}, journal = {Journal of theoretical biology}, volume = {434}, number = {}, pages = {34-41}, doi = {10.1016/j.jtbi.2017.03.008}, pmid = {28302492}, issn = {1095-8541}, mesh = {*Biological Evolution ; *Microbiota ; Research ; *Symbiosis ; Terminology as Topic ; }, abstract = {In her influential 1967 paper, Lynn Margulis synthesized a range of data to support the idea of endosymbiosis. Building on the success of this work, she applied the same methodology to promote the role of symbiosis more generally in evolution. As part of this broader project, she coined the term 'holobiont' to refer to a unified entity of symbiont and host. This concept is now applied with great gusto in microbiome research, and often implies not just a physiological unit but also various senses of an evolving system. My analysis will track how Margulis came to propose the term, its current use in microbiome research, and how those applications link back to Margulis. I then evaluate what contemporary use says about Margulis's legacy for microbiome research.}, }
@article {pmid28296889, year = {2017}, author = {Cowart, DA and Durand, L and Cambon-Bonavita, MA and Arnaud-Haond, S}, title = {Investigation of bacterial communities within the digestive organs of the hydrothermal vent shrimp Rimicaris exoculata provide insights into holobiont geographic clustering.}, journal = {PloS one}, volume = {12}, number = {3}, pages = {e0172543}, doi = {10.1371/journal.pone.0172543}, pmid = {28296889}, issn = {1932-6203}, mesh = {Animals ; Crustacea/*microbiology ; Gastrointestinal Tract/*microbiology ; *Geography ; }, abstract = {Prokaryotic communities forming symbiotic relationships with the vent shrimp, Rimicaris exoculata, are well studied components of hydrothermal ecosystems at the Mid-Atlantic Ridge (MAR). Despite the tight link between host and symbiont, the observed lack of spatial genetic structure seen in R. exoculata contrasts with the geographic differentiation detected in specific bacterial ectosymbionts. The geographic clustering of bacterial lineages within a seemingly panmictic host suggests either the presence of finer scale restriction to gene flow not yet detected in the host, horizontal transmission (environmental selection) of its endosymbionts as a consequence of unique vent geochemistry, or vertically transmitted endosymbionts that exhibit genetic differentiation. To identify which hypothesis best fits, we tested whether bacterial assemblages exhibit differentiation across sites or host populations by performing a 16S rRNA metabarcoding survey on R. exoculata digestive prokaryote samples (n = 31) taken from three geochemically distinct vents across MAR: Rainbow, Trans-Atlantic Geotraverse (TAG) and Logatchev. Analysis of communities across two organs (digestive tract, stomach), three molt colors (white, red, black) and three life stages (eggs, juveniles, adults) also provided insights into symbiont transmission mode. Examining both whole communities and operational taxonomic units (OTUs) confirmed the presence of three main epibionts: Epsilonproteobacteria, Mollicutes and Deferribacteres. With these findings, we identified a clear pattern of geographic segregation by vent in OTUs assigned to Epsilonproteobacteria. Additionally, we detected evidence for differentiation among all communities associated to vents and life stages. Overall, results suggest a combination of environmental selection and vertical inheritance of some of the symbiotic lineages.}, }
@article {pmid28295957, year = {2017}, author = {Partida-Martínez, LP}, title = {The fungal holobiont: Evidence from early diverging fungi.}, journal = {Environmental microbiology}, volume = {19}, number = {8}, pages = {2919-2923}, doi = {10.1111/1462-2920.13731}, pmid = {28295957}, issn = {1462-2920}, }
@article {pmid28290203, year = {2017}, author = {Eymann, C and Lassek, C and Wegner, U and Bernhardt, J and Fritsch, OA and Fuchs, S and Otto, A and Albrecht, D and Schiefelbein, U and Cernava, T and Aschenbrenner, I and Berg, G and Grube, M and Riedel, K}, title = {Symbiotic Interplay of Fungi, Algae, and Bacteria within the Lung Lichen Lobaria pulmonaria L. Hoffm. as Assessed by State-of-the-Art Metaproteomics.}, journal = {Journal of proteome research}, volume = {16}, number = {6}, pages = {2160-2173}, doi = {10.1021/acs.jproteome.6b00974}, pmid = {28290203}, issn = {1535-3907}, mesh = {*Ascomycota ; Biodiversity ; *Chlorophyta ; *Cyanobacteria ; *Lichens ; Metabolomics ; Microbial Interactions ; Proteomics ; Pulmonaria ; *Symbiosis ; }, abstract = {Lichens are recognized by macroscopic structures formed by a heterotrophic fungus, the mycobiont, which hosts internal autotrophic photosynthetic algal and/or cyanobacterial partners, referred to as the photobiont. We analyzed the structure and functionality of the entire lung lichen Lobaria pulmonaria L. Hoffm. collected from two different sites by state-of-the-art metaproteomics. In addition to the green algae and the ascomycetous fungus, a lichenicolous fungus as well as a complex prokaryotic community (different from the cyanobacteria) was found, the latter dominated by methanotrophic Rhizobiales. Various partner-specific proteins could be assigned to the different lichen symbionts, for example, fungal proteins involved in vesicle transport, algal proteins functioning in photosynthesis, cyanobacterial nitrogenase and GOGAT involved in nitrogen fixation, and bacterial enzymes responsible for methanol/C1-compound metabolism as well as CO-detoxification. Structural and functional information on proteins expressed by the lichen community complemented and extended our recent symbiosis model depicting the functional multiplayer network of single holobiont partners.1 Our new metaproteome analysis strongly supports the hypothesis (i) that interactions within the self-supporting association are multifaceted and (ii) that the strategy of functional diversification within the single lichen partners may support the longevity of L. pulmonaria under certain ecological conditions.}, }
@article {pmid28245221, year = {2017}, author = {Richardson, LA}, title = {Evolving as a holobiont.}, journal = {PLoS biology}, volume = {15}, number = {2}, pages = {e2002168}, doi = {10.1371/journal.pbio.2002168}, pmid = {28245221}, issn = {1545-7885}, }
@article {pmid28233813, year = {2017}, author = {Weigel, BL and Erwin, PM}, title = {Effects of reciprocal transplantation on the microbiome and putative nitrogen cycling functions of the intertidal sponge, Hymeniacidon heliophila.}, journal = {Scientific reports}, volume = {7}, number = {}, pages = {43247}, doi = {10.1038/srep43247}, pmid = {28233813}, issn = {2045-2322}, abstract = {Microbial symbionts in sponges are ubiquitous, forming complex and highly diverse host-specific communities. Conspecific sponges display remarkable stability in their symbiont communities, both spatially and temporally, yet extreme fluctuations in environmental factors can cause shifts in host-symbiont associations. We previously demonstrated that the marine sponge Hymeniacidon heliophila displayed significant community-level differences in microbial symbiont diversity, structure and composition when sampled from intertidal and subtidal environments. Here, we conducted a 70-day reciprocal transplant experiment to directly test the effect of tidal exposure on the microbiome of H. heliophila, using next-generation Illumina sequencing of 16S rRNA gene sequences to characterize symbiont communities. While sponges transplanted between habitats displayed shifts in microbial communities after 70 days, temporal variation was the dominant factor affecting microbial community composition. Further, we identified core symbionts that persisted across these spatio-temporal scales and used a metagenomic approach to show that these dominant members of the microbiome of H. heliophila represent nitrogen cycling taxa that have the potential to contribute to a diverse array of nitrogen transformations in the sponge holobiont. Together, these results indicate that despite moderate spatio-temporal shifts in symbiont composition, core symbiont functions (e.g. nitrogen cycling) can be maintained in sponge microbiomes through functional redundancy.}, }
@article {pmid28223979, year = {2017}, author = {Leite, DC and Leão, P and Garrido, AG and Lins, U and Santos, HF and Pires, DO and Castro, CB and van Elsas, JD and Zilberberg, C and Rosado, AS and Peixoto, RS}, title = {Broadcast Spawning Coral Mussismilia hispida Can Vertically Transfer its Associated Bacterial Core.}, journal = {Frontiers in microbiology}, volume = {8}, number = {}, pages = {176}, doi = {10.3389/fmicb.2017.00176}, pmid = {28223979}, issn = {1664-302X}, abstract = {The hologenome theory of evolution (HTE), which is under fierce debate, presupposes that parts of the microbiome are transmitted from one generation to the next [vertical transmission (VT)], which may also influence the evolution of the holobiont. Even though bacteria have previously been described in early life stages of corals, these early life stages (larvae) could have been inoculated in the water and not inside the parental colony (through gametes) carrying the parental microbiome. How Symbiodinium is transmitted to offspring is also not clear, as only one study has described this mechanism in spawners. All other studies refer to incubators. To explore the VT hypothesis and the key components being transferred, colonies of the broadcast spawner species Mussismilia hispida were kept in nurseries until spawning. Gamete bundles, larvae and adult corals were analyzed to identify their associated microbiota with respect to composition and location. Symbiodinium and bacteria were detected by sequencing in gametes and coral planula larvae. However, no cells were detected using microscopy at the gamete stage, which could be related to the absence of those cells inside the oocytes/dispersed in the mucus or to a low resolution of our approach. A preliminary survey of Symbiodinium diversity indicated that parental colonies harbored Symbiodinium clades B, C and G, whereas only clade B was found in oocytes and planula larvae [5 days after fertilization (a.f.)]. The core bacterial populations found in the bundles, planula larvae and parental colonies were identified as members of the genera Burkholderia, Pseudomonas, Acinetobacter, Ralstonia, Inquilinus and Bacillus, suggesting that these populations could be vertically transferred through the mucus. The collective data suggest that spawner corals, such as M. hispida, can transmit Symbiodinium cells and the bacterial core to their offspring by a coral gamete (and that this gamete, with its bacterial load, is released into the water), supporting the HTE. However, more data are required to indicate the stability of the transmitted populations to indicate whether the holobiont can be considered a unit of natural selection or a symbiotic assemblage of independently evolving organisms.}, }
@article {pmid28152002, year = {2017}, author = {Goulet, TL and Shirur, KP and Ramsby, BD and Iglesias-Prieto, R}, title = {The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.}, journal = {PloS one}, volume = {12}, number = {2}, pages = {e0171032}, doi = {10.1371/journal.pone.0171032}, pmid = {28152002}, issn = {1932-6203}, mesh = {Acclimatization/physiology ; Animals ; Anthozoa/chemistry/*physiology ; Caribbean Region ; Chlorophyll/analysis/metabolism ; Dinoflagellida/genetics/*physiology ; Enzymes/metabolism ; Genotype ; Mexico ; Seawater ; Symbiosis/physiology ; Temperature ; }, abstract = {Global climate change not only leads to elevated seawater temperatures but also to episodic anomalously high or low temperatures lasting for several hours to days. Scleractinian corals are detrimentally affected by thermal fluctuations, which often lead to an uncoupling of their mutualism with Symbiodinium spp. (coral bleaching) and potentially coral death. Consequently, on many Caribbean reefs scleractinian coral cover has plummeted. Conversely, gorgonian corals persist, with their abundance even increasing. How gorgonians react to thermal anomalies has been investigated utilizing limited parameters of either the gorgonian, Symbiodinium or the combined symbiosis (holobiont). We employed a holistic approach to examine the effect of an experimental five-day elevated temperature episode on parameters of the host, symbiont, and the holobiont in Eunicea tourneforti, E. flexuosa and Pseudoplexaura porosa. These gorgonian corals reacted and coped with 32°C seawater temperatures. Neither Symbiodinium genotypes nor densities differed between the ambient 29.5°C and 32°C. Chlorophyll a and c2 per Symbiodinium cell, however, were lower at 32°C leading to a reduction in chlorophyll content in the branches and an associated reduction in estimated absorbance and increase in the chlorophyll a specific absorption coefficient. The adjustments in the photochemical parameters led to changes in photochemical efficiencies, although these too showed that the gorgonians were coping. For example, the maximum excitation pressure, Qm, was significantly lower at 32°C than at 29.5°C. In addition, although per dry weight the amount of protein and lipids were lower at 32°C, the overall energy content in the tissues did not differ between the temperatures. Antioxidant activity either remained the same or increased following exposure to 32°C further reiterating a response that dealt with the stressor. Taken together, the capability of Caribbean gorgonian corals to modify symbiont, host and consequently holobiont parameters may partially explain their persistence on reefs faced with climate change.}, }
@article {pmid28133884, year = {2017}, author = {Arnaud-Haond, S and Aires, T and Candeias, R and Teixeira, SJL and Duarte, CM and Valero, M and Serrão, EA}, title = {Entangled fates of holobiont genomes during invasion: nested bacterial and host diversities in Caulerpa taxifolia.}, journal = {Molecular ecology}, volume = {26}, number = {8}, pages = {2379-2391}, doi = {10.1111/mec.14030}, pmid = {28133884}, issn = {1365-294X}, mesh = {Bacteria/classification ; Caulerpa/*genetics/*microbiology ; DNA, Bacterial/genetics ; *Genetic Variation ; Genetics, Population ; Genotype ; *Introduced Species ; Mediterranean Sea ; *Microbiota ; Microsatellite Repeats ; RNA, Ribosomal, 16S/genetics ; South Australia ; *Symbiosis ; }, abstract = {Successful prevention and mitigation of biological invasions requires retracing the initial steps of introduction, as well as understanding key elements enhancing the adaptability of invasive species. We studied the genetic diversity of the green alga Caulerpa taxifolia and its associated bacterial communities in several areas around the world. The striking congruence of α and β diversity of the algal genome and endophytic communities reveals a tight association, supporting the holobiont concept as best describing the unit of spreading and invasion. Both genomic compartments support the hypotheses of a unique accidental introduction in the Mediterranean and of multiple invasion events in southern Australia. In addition to helping with tracing the origin of invasion, bacterial communities exhibit metabolic functions that can potentially enhance adaptability and competitiveness of the consortium they form with their host. We thus hypothesize that low genetic diversities of both host and symbiont communities may contribute to the recent regression in the Mediterranean, in contrast with the persistence of highly diverse assemblages in southern Australia. This study supports the importance of scaling up from the host to the holobiont for a comprehensive understanding of invasions.}, }
@article {pmid28119709, year = {2016}, author = {Rotini, A and Mejia, AY and Costa, R and Migliore, L and Winters, G}, title = {Ecophysiological Plasticity and Bacteriome Shift in the Seagrass Halophila stipulacea along a Depth Gradient in the Northern Red Sea.}, journal = {Frontiers in plant science}, volume = {7}, number = {}, pages = {2015}, doi = {10.3389/fpls.2016.02015}, pmid = {28119709}, issn = {1664-462X}, abstract = {Halophila stipulacea is a small tropical seagrass species. It is the dominant seagrass species in the Gulf of Aqaba (GoA; northern Red Sea), where it grows in both shallow and deep environments (1-50 m depth). Native to the Red Sea, Persian Gulf, and Indian Ocean, this species has invaded the Mediterranean and has recently established itself in the Caribbean Sea. Due to its invasive nature, there is growing interest to understand this species' capacity to adapt to new conditions, which might be attributed to its ability to thrive in a broad range of ecological niches. In this study, a multidisciplinary approach was used to depict variations in morphology, biochemistry (pigment and phenol content) and epiphytic bacterial communities along a depth gradient (4-28 m) in the GoA. Along this gradient, H. stipulacea increased leaf area and pigment contents (Chlorophyll a and b, total Carotenoids), while total phenol contents were mostly uniform. H. stipulacea displayed a well conserved core bacteriome, as assessed by 454-pyrosequencing of 16S rRNA gene reads amplified from metagenomic DNA. The core bacteriome aboveground (leaves) and belowground (roots and rhizomes), was composed of more than 100 Operational Taxonomic Units (OTUs) representing 63 and 52% of the total community in each plant compartment, respectively, with a high incidence of the classes Alphaproteobacteria, Gammaproteobacteria, and Deltaproteobacteria across all depths. Above and belowground communities were different and showed higher within-depth variability at the intermediate depths (9 and 18 m) than at the edges. Plant parts showed a clear influence in shaping the communities while depth showed a greater influence on the belowground communities. Overall, results highlighted a different ecological status of H. stipulacea at the edges of the gradient (4-28 m), where plants showed not only marked differences in morphology and biochemistry, but also the most distinct associated bacterial consortium. We demonstrated the pivotal role of morphology, biochemistry (pigment and phenol content), and epiphytic bacterial communities in helping plants to cope with environmental and ecological variations. The plant/holobiont capability to persist and adapt to environmental changes probably has an important role in its ecological resilience and invasiveness.}, }
@article {pmid28115399, year = {2017}, author = {Esteves, AI and Cullen, A and Thomas, T}, title = {Competitive interactions between sponge-associated bacteria.}, journal = {FEMS microbiology ecology}, volume = {93}, number = {3}, pages = {}, doi = {10.1093/femsec/fix008}, pmid = {28115399}, issn = {1574-6941}, mesh = {Animals ; Bacillus/genetics ; Bacteria/genetics/*metabolism ; Biotechnology ; Microbiota ; Phylogeny ; Porifera/*microbiology ; RNA, Ribosomal, 16S/genetics ; Rhodobacteraceae/genetics/physiology ; }, abstract = {The diversity of the microbial communities associated with marine sponges has been extensively studied, but their functioning and interactions within the sponge holobiont are only recently being appreciated. Sponge-associated microorganisms are known for the production of a range of inhibitory metabolites with biotechnological application, but the ecological role that these compounds remains elusive. In this work, we explore the competitive interactions between cultivated sponge-associated bacteria to inspect whether bacteria that produce antimicrobial activities are able to inhibit potentially pathogenic bacteria. We isolated a Bacillus sp. bacterium with sponge-degrading activity, which likely has a negative impact on the host. This bacterium, along with other sponge isolates from the same genus, was found to be inhibited by a subpopulation of closely related sponge-derived Pseudovibrio spp. In some Pseudovibrio strains, these inhibitory activities were correlated with the genetic capacity to produce polyketides, such as erythronolide. Our observations suggest that antagonistic activities likely influence the composition of the sponge microbiome, including the abundance of bacteria that can be harmful to the host.}, }
@article {pmid28103686, year = {2017}, author = {Alcolombri, U and Lei, L and Meltzer, D and Vardi, A and Tawfik, DS}, title = {Assigning the Algal Source of Dimethylsulfide Using a Selective Lyase Inhibitor.}, journal = {ACS chemical biology}, volume = {12}, number = {1}, pages = {41-46}, doi = {10.1021/acschembio.6b00844}, pmid = {28103686}, issn = {1554-8937}, mesh = {Animals ; Anthozoa/drug effects/enzymology/*metabolism ; Bacteria/drug effects/enzymology/metabolism ; Carbon-Sulfur Lyases/antagonists &amp; inhibitors/metabolism ; Enzyme Inhibitors/metabolism ; Haptophyta/drug effects/enzymology/*metabolism ; Oceans and Seas ; Sulfides/*metabolism ; }, abstract = {Atmospheric dimethylsulfide (DMS) is massively produced in the oceans by bacteria, algae, and corals. To enable identification of DMS sources, we developed a potent mechanism-based inhibitor of the algal Alma dimethylsulfoniopropionate lyase family that does not inhibit known bacterial lyases. Its application to coral holobiont indicates that DMS originates from Alma lyase(s). This biochemical profiling may complement meta-genomics and transcriptomics to provide better understanding of the marine sulfur cycle.}, }
@article {pmid28097070, year = {2017}, author = {Fiore, CL and Freeman, CJ and Kujawinski, EB}, title = {Sponge exhalent seawater contains a unique chemical profile of dissolved organic matter.}, journal = {PeerJ}, volume = {5}, number = {}, pages = {e2870}, doi = {10.7717/peerj.2870}, pmid = {28097070}, issn = {2167-8359}, abstract = {Sponges are efficient filter feeders, removing significant portions of particulate and dissolved organic matter (POM, DOM) from the water column. While the assimilation and respiration of POM and DOM by sponges and their abundant microbial symbiont communities have received much attention, there is virtually no information on the impact of sponge holobiont metabolism on the composition of DOM at a molecular-level. We applied untargeted and targeted metabolomics techniques to characterize DOM in seawater samples prior to entering the sponge (inhalant reef water), in samples exiting the sponge (exhalent seawater), and in samples collected just outside the reef area (off reef seawater). Samples were collected from two sponge species, Ircinia campana and Spheciospongia vesparium, on a near-shore hard bottom reef in the Florida Keys. Metabolic profiles generated from untargeted metabolomics analysis indicated that many more compounds were enhanced in the exhalent samples than in the inhalant samples. Targeted metabolomics analysis revealed differences in diversity and concentration of metabolites between exhalent and off reef seawater. For example, most of the nucleosides were enriched in the exhalent seawater, while the aromatic amino acids, caffeine and the nucleoside xanthosine were elevated in the off reef water samples. Although the metabolic profile of the exhalent seawater was unique, the impact of sponge metabolism on the overall reef DOM profile was spatially limited in our study. There were also no significant differences in the metabolic profiles of exhalent water between the two sponge species, potentially indicating that there is a characteristic DOM profile in the exhalent seawater of Caribbean sponges. Additional work is needed to determine whether the impact of sponge DOM is greater in habitats with higher sponge cover and diversity. This work provides the first insight into the molecular-level impact of sponge holobiont metabolism on reef DOM and establishes a foundation for future experimental studies addressing the influence of sponge-derived DOM on chemical and ecological processes in coral reef ecosystems.}, }
@article {pmid28088765, year = {2017}, author = {Karlin, EF and Smouse, PE}, title = {Allo-allo-triploid Sphagnum × falcatulum: single individuals contain most of the Holantarctic diversity for ancestrally indicative markers.}, journal = {Annals of botany}, volume = {120}, number = {2}, pages = {221-231}, doi = {10.1093/aob/mcw269}, pmid = {28088765}, issn = {1095-8290}, mesh = {Alleles ; Argentina ; Australia ; *Biological Evolution ; Chile ; Genetic Variation ; Genome, Plant ; *Hybridization, Genetic ; Microsatellite Repeats ; New Zealand ; Sphagnopsida/*genetics ; Tasmania ; *Triploidy ; }, abstract = {Background and Aims: Allopolyploids exhibit both different levels and different patterns of genetic variation than are typical of diploids. However, scant attention has been given to the partitioning of allelic information and diversity in allopolyploids, particularly that among homeologous monoploid components of the hologenome. Sphagnum × falcatulum is a double allopolyploid peat moss that spans a considerable portion of the Holantarctic. With monoploid genomes from three ancestral species, this organism exhibits a complex evolutionary history involving serial inter-subgeneric allopolyploidizations.<br><br>Methods: Studying populations from three disjunct regions [South Island (New Zealand); Tierra de Fuego archipelago (Chile, Argentina); Tasmania (Australia)], allelic information for five highly stable microsatellite markers that differed among the three (ancestral) monoploid genomes was examined. Using Shannon information and diversity measures, the holoploid information, as well as the information within and among the three component monoploid genomes, was partitioned into separate components for individuals within and among populations and regions, and those information components were then converted into corresponding diversity measures.<br><br>Key Results: The majority (76 %) of alleles detected across these five markers are most likely to have been captured by hybridization, but the information within each of the three monoploid genomes varied, suggesting a history of recurrent allopolyploidization between ancestral species containing different levels of genetic diversity. Information within individuals, equivalent to the information among monoploid genomes (for this dataset), was relatively stable, and represented 83 % of the grand total information across the Holantarctic, with both inter-regional and inter-population diversification each accounting for about 5 % of the total information.<br><br>Conclusions: Sphagnum × falcatulum probably inherited the great majority of its genetic diversity at these markers by reticulation, rather than by subsequent evolutionary radiation. However, some post-hybridization genetic diversification has become fixed in at least one regional population. Methodology allowing statistical analysis of any ploidy level is presented.}, }
@article {pmid28066403, year = {2016}, author = {Pita, L and Fraune, S and Hentschel, U}, title = {Emerging Sponge Models of Animal-Microbe Symbioses.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {2102}, doi = {10.3389/fmicb.2016.02102}, pmid = {28066403}, issn = {1664-302X}, abstract = {Sponges have a significant impact on marine benthic communities, they are of biotechnological interest owing to their production of bioactive natural compounds, and they promise to provide insights into conserved mechanisms of host-microbe interactions in basal metazoans. The natural variability of sponge-microbe associations across species and environments provides a meaningful ecological and evolutionary framework to investigate animal-microbial symbiosis through experimentation in the field and also in aquaria. In addition, next-generation sequencing technologies have shed light on the genomic repertoire of the sponge host and revealed metabolic capacities and symbiotic lifestyle features of their microbiota. However, our understanding of symbiotic mechanisms is still in its infancy. Here, we discuss the potential and limitations of the sponge-microbe symbiosis as emerging models for animal-associated microbiota.}, }
@article {pmid28050778, year = {2017}, author = {Miller, WB and Torday, JS}, title = {A systematic approach to cancer: evolution beyond selection.}, journal = {Clinical and translational medicine}, volume = {6}, number = {1}, pages = {2}, doi = {10.1186/s40169-016-0131-4}, pmid = {28050778}, issn = {2001-1326}, abstract = {Cancer is typically scrutinized as a pathological process characterized by chromosomal aberrations and clonal expansion subject to stochastic Darwinian selection within adaptive cellular ecosystems. Cognition based evolution is suggested as an alternative approach to cancer development and progression in which neoplastic cells of differing karyotypes and cellular lineages are assessed as self-referential agencies with purposive participation within tissue microenvironments. As distinct self-aware entities, neoplastic cells occupy unique participant/observer status within tissue ecologies. In consequence, neoplastic proliferation by clonal lineages is enhanced by the advantaged utilization of ecological resources through flexible re-connection with progenitor evolutionary stages.}, }
@article {pmid28003808, year = {2016}, author = {Gopal, M and Gupta, A}, title = {Microbiome Selection Could Spur Next-Generation Plant Breeding Strategies.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1971}, doi = {10.3389/fmicb.2016.01971}, pmid = {28003808}, issn = {1664-302X}, abstract = {&quot;No plant is an island too…&quot; Plants, though sessile, have developed a unique strategy to counter biotic and abiotic stresses by symbiotically co-evolving with microorganisms and tapping into their genome for this purpose. Soil is the bank of microbial diversity from which a plant selectively sources its microbiome to suit its needs. Besides soil, seeds, which carry the genetic blueprint of plants during trans-generational propagation, are home to diverse microbiota that acts as the principal source of microbial inoculum in crop cultivation. Overall, a plant is ensconced both on the outside and inside with a diverse assemblage of microbiota. Together, the plant genome and the genes of the microbiota that the plant harbors in different plant tissues, i.e., the 'plant microbiome,' form the holobiome which is now considered as unit of selection: 'the holobiont.' The 'plant microbiome' not only helps plants to remain fit but also offers critical genetic variability, hitherto, not employed in the breeding strategy by plant breeders, who traditionally have exploited the genetic variability of the host for developing high yielding or disease tolerant or drought resistant varieties. This fresh knowledge of the microbiome, particularly of the rhizosphere, offering genetic variability to plants, opens up new horizons for breeding that could usher in cultivation of next-generation crops depending less on inorganic inputs, resistant to insect pest and diseases and resilient to climatic perturbations. We surmise, from ever increasing evidences, that plants and their microbial symbionts need to be co-propagated as life-long partners in future strategies for plant breeding. In this perspective, we propose bottom-up approach to co-propagate the co-evolved, the plant along with the target microbiome, through - (i) reciprocal soil transplantation method, or (ii) artificial ecosystem selection method of synthetic microbiome inocula, or (iii) by exploration of microRNA transfer method - for realizing this next-generation plant breeding approach. Our aim, thus, is to bring closer the information accrued through the advanced nucleotide sequencing and bioinformatics in conjunction with conventional culture-dependent isolation method for practical application in plant breeding and overall agriculture.}, }
@article {pmid27995440, year = {2017}, author = {Catania, F and Krohs, U and Chittò, M and Ferro, D and Ferro, K and Lepennetier, G and Görtz, HD and Schreiber, RS and Kurtz, J and Gadau, J}, title = {The hologenome concept: we need to incorporate function.}, journal = {Theory in biosciences = Theorie in den Biowissenschaften}, volume = {136}, number = {3-4}, pages = {89-98}, doi = {10.1007/s12064-016-0240-z}, pmid = {27995440}, issn = {1611-7530}, mesh = {*Adaptation, Biological ; Animals ; Anthozoa ; *Biological Evolution ; Biology/*methods ; Drosophila ; Ecology/*methods ; Fungi ; Humans ; Paramecium ; Phenotype ; Plants ; Rickettsia ; Symbiosis ; }, abstract = {Are we in the midst of a paradigm change in biology and have animals and plants lost their individuality, i.e., are even so-called 'typical' organisms no longer organisms in their own right? Is the study of the holobiont-host plus its symbiotic microorganisms-no longer optional, but rather an obligatory path that must be taken for a comprehensive understanding of the ecology and evolution of the individual components that make up a holobiont? Or are associated microbes merely a component of their host's environment, and the holobiont concept is just a beautiful idea that does not add much or anything to our understanding of evolution? This article explores different aspects of the concept of the holobiont. We focus on the aspect of functional integration, a central holobiont property, which is only rarely considered thoroughly. We conclude that the holobiont comes in degrees, i.e., we regard the property of being a holobiont as a continuous trait that we term holobiontness, and that holobiontness is differentiated in several dimensions. Although the holobiont represents yet another level of selection (different from classical individual or group selection because it acts on a system that is composed of multiple species), it depends on the grade of functional integration whether or not the holobiont concept helps to cast light on the various degrees of interactions between symbiotic partners.}, }
@article {pmid27980125, year = {2017}, author = {Hawkins, TD and Warner, ME}, title = {Warm preconditioning protects against acute heat-induced respiratory dysfunction and delays bleaching in a symbiotic sea anemone.}, journal = {The Journal of experimental biology}, volume = {220}, number = {Pt 6}, pages = {969-983}, doi = {10.1242/jeb.150391}, pmid = {27980125}, issn = {1477-9145}, mesh = {*Acclimatization ; Animals ; Dinoflagellida/enzymology/*physiology ; Heat-Shock Response ; Hot Temperature ; Mitochondria/enzymology/metabolism ; Oxygen Consumption ; Photosynthesis ; Sea Anemones/enzymology/*physiology ; *Symbiosis ; }, abstract = {Preconditioning to non-stressful warming can protect some symbiotic cnidarians against the high temperature-induced collapse of their mutualistic endosymbiosis with photosynthetic dinoflagellates (Symbiodinium spp.), a process known as bleaching. Here, we sought to determine whether such preconditioning is underpinned by differential regulation of aerobic respiration. We quantified in vivo metabolism and mitochondrial respiratory enzyme activity in the naturally symbiotic sea anemone Exaiptasia pallida preconditioned to 30°C for >7 weeks as well as anemones kept at 26°C. Preconditioning resulted in increased Symbiodinium photosynthetic activity and holobiont (host+symbiont) respiration rates. Biomass-normalised activities of host respiratory enzymes [citrate synthase and the mitochondrial electron transport chain (mETC) complexes I and IV] were higher in preconditioned animals, suggesting that increased holobiont respiration may have been due to host mitochondrial biogenesis and/or enlargement. Subsequent acute heating of preconditioned and 'thermally naive' animals to 33°C induced dramatic increases in host mETC complex I and Symbiodinium mETC complex II activities only in thermally naive E. pallida These changes were not reflected in the activities of other respiratory enzymes. Furthermore, bleaching in preconditioned E. pallida (defined as the significant loss of symbionts) was delayed by several days relative to the thermally naive group. These findings suggest that changes to mitochondrial biogenesis and/or function in symbiotic cnidarians during warm preconditioning might play a protective role during periods of exposure to stressful heating.}, }
@article {pmid27958345, year = {2016}, author = {Pineda, MC and Strehlow, B and Duckworth, A and Doyle, J and Jones, R and Webster, NS}, title = {Effects of light attenuation on the sponge holobiont- implications for dredging management.}, journal = {Scientific reports}, volume = {6}, number = {}, pages = {39038}, doi = {10.1038/srep39038}, pmid = {27958345}, issn = {2045-2322}, mesh = {Animals ; Biota/*physiology ; *Light ; Porifera/*physiology ; Symbiosis/*physiology ; }, abstract = {Dredging and natural sediment resuspension events can cause high levels of turbidity, reducing the amount of light available for photosynthetic benthic biota. To determine how marine sponges respond to light attenuation, five species were experimentally exposed to a range of light treatments. Tolerance thresholds and capacity for recovery varied markedly amongst species. Whilst light attenuation had no effect on the heterotrophic species Stylissa flabelliformis and Ianthella basta, the phototrophic species Cliona orientalis and Carteriospongia foliascens discoloured (bleached) over a 28 day exposure period to very low light (<0.8 mol photons m-2 d-1). In darkness, both species discoloured within a few days, concomitant with reduced fluorescence yields, chlorophyll concentrations and shifts in their associated microbiomes. The phototrophic species Cymbastela coralliophila was less impacted by light reduction. C. orientalis and C. coralliophila exhibited full recovery under normal light conditions, whilst C. foliascens did not recover and showed high levels of mortality. The light treatments used in the study are directly relevant to conditions that can occur in situ during dredging projects, indicating that light attenuation poses a risk to photosynthetic marine sponges. Examining benthic light levels over temporal scales would enable dredging proponents to be aware of conditions that could impact on sponge physiology.}, }
@article {pmid27924868, year = {2016}, author = {Diaz, JM and Hansel, CM and Apprill, A and Brighi, C and Zhang, T and Weber, L and McNally, S and Xun, L}, title = {Species-specific control of external superoxide levels by the coral holobiont during a natural bleaching event.}, journal = {Nature communications}, volume = {7}, number = {}, pages = {13801}, doi = {10.1038/ncomms13801}, pmid = {27924868}, issn = {2041-1723}, abstract = {The reactive oxygen species superoxide (O2·-) is both beneficial and detrimental to life. Within corals, superoxide may contribute to pathogen resistance but also bleaching, the loss of essential algal symbionts. Yet, the role of superoxide in coral health and physiology is not completely understood owing to a lack of direct in situ observations. By conducting field measurements of superoxide produced by corals during a bleaching event, we show substantial species-specific variation in external superoxide levels, which reflect the balance of production and degradation processes. Extracellular superoxide concentrations are independent of light, algal symbiont abundance and bleaching status, but depend on coral species and bacterial community composition. Furthermore, coral-derived superoxide concentrations ranged from levels below bulk seawater up to ∼120 nM, some of the highest superoxide concentrations observed in marine systems. Overall, these results unveil the ability of corals and/or their microbiomes to regulate superoxide in their immediate surroundings, which suggests species-specific roles of superoxide in coral health and physiology.}, }
@article {pmid27920768, year = {2016}, author = {Zhang, Y and Yang, Q and Ling, J and Van Nostrand, JD and Shi, Z and Zhou, J and Dong, J}, title = {The Shifts of Diazotrophic Communities in Spring and Summer Associated with Coral Galaxea astreata, Pavona decussata, and Porites lutea.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1870}, doi = {10.3389/fmicb.2016.01870}, pmid = {27920768}, issn = {1664-302X}, abstract = {The coral holobiont often resides in oligotrophic waters; both coral cells and their symbiotic dinoflagellates possess ammonium assimilation enzymes and potentially benefit from the nitrogen fixation of coral-associated diazotrophs. However, the seasonal dynamics of coral-associated diazotrophs are not well characterized. Here, the seasonal variations of diazotrophic communities associated with three corals, Galaxea astreata, Pavona decussata, and Porites lutea, were studied using nifH gene amplicon pyrosequencing techniques. Our results revealed a great diversity of coral-associated diazotrophs. nifH sequences related to Alphaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria were ubiquitous and dominant in all corals in two seasons. In contrast with the coral P. decussata, both G. astreata and P. lutea showed significant seasonal changes in the diazotrophic communities and nifH gene abundance. Variable diazotroph groups accounted for a range from 11 to 49% within individual coral samples. Most of the variable diazotrophic groups from P. decussata were species-specific, however, the majority of overlapping variable groups in G. astreata and P. lutea showed the same seasonal variation characteristics. Rhodopseudomonas palustris- and Gluconacetobacter diazotrophicus-affiliated sequences were relatively abundant in the summer, whereas a nifH sequence related to Halorhodospira halophila was relatively abundant in spring G. astreata and P. lutea. The seasonal variations of all diazotrophic communities were significantly correlated with the seasonal shifts of ammonium and nitrate, suggesting that diazotrophs play an important role in the nitrogen cycle of the coral holobiont.}, }
@article {pmid27919551, year = {2017}, author = {Hernandez-Agreda, A and Gates, RD and Ainsworth, TD}, title = {Defining the Core Microbiome in Corals' Microbial Soup.}, journal = {Trends in microbiology}, volume = {25}, number = {2}, pages = {125-140}, doi = {10.1016/j.tim.2016.11.003}, pmid = {27919551}, issn = {1878-4380}, mesh = {Animals ; Anthozoa/*microbiology/*parasitology ; Bacteria/*isolation &amp; purification ; *Coral Reefs ; Dinoflagellida/*isolation &amp; purification ; Dysbiosis/microbiology ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; Symbiosis/physiology ; }, abstract = {Corals are considered one of the most complex microbial biospheres studied to date, hosting thousands of bacterial phylotypes in species-specific associations. There are, however, substantial knowledge gaps and challenges in understanding the functional significance of bacterial communities and bacterial symbioses of corals. The ubiquitous nature of some bacterial interactions has only recently been investigated and an accurate differentiation between the healthy (symbiotic) and unhealthy (dysbiotic) microbial state has not yet been determined. Here we review the complexity of the coral holobiont, coral microbiome diversity, and recently proposed bacterial symbioses of corals. We provide insight into coupling the core microbiome framework with community ecology principals, and draw on the theoretical insights from other complex systems, to build a framework to aid in deciphering ecologically significant microbes within a corals' microbial soup.}, }
@article {pmid27908589, year = {2017}, author = {Shapira, M}, title = {Adaptation from Within or from Without: A Reply to Rodrigo et al.}, journal = {Trends in ecology &amp; evolution}, volume = {32}, number = {2}, pages = {85}, doi = {10.1016/j.tree.2016.11.003}, pmid = {27908589}, issn = {1872-8383}, mesh = {*Adaptation, Physiological ; Humans ; *Symbiosis ; }, }
@article {pmid27907979, year = {2017}, author = {Webster, NS}, title = {Conceptual and methodological advances for holobiont research.}, journal = {Environmental microbiology reports}, volume = {9}, number = {1}, pages = {30-32}, doi = {10.1111/1758-2229.12500}, pmid = {27907979}, issn = {1758-2229}, }
@article {pmid27877161, year = {2016}, author = {Horn, H and Slaby, BM and Jahn, MT and Bayer, K and Moitinho-Silva, L and Förster, F and Abdelmohsen, UR and Hentschel, U}, title = {An Enrichment of CRISPR and Other Defense-Related Features in Marine Sponge-Associated Microbial Metagenomes.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1751}, doi = {10.3389/fmicb.2016.01751}, pmid = {27877161}, issn = {1664-302X}, abstract = {Many marine sponges are populated by dense and taxonomically diverse microbial consortia. We employed a metagenomics approach to unravel the differences in the functional gene repertoire among three Mediterranean sponge species, Petrosia ficiformis, Sarcotragus foetidus, Aplysina aerophoba and seawater. Different signatures were observed between sponge and seawater metagenomes with regard to microbial community composition, GC content, and estimated bacterial genome size. Our analysis showed further a pronounced repertoire for defense systems in sponge metagenomes. Specifically, clustered regularly interspaced short palindromic repeats, restriction modification, DNA phosphorothioation and phage growth limitation systems were enriched in sponge metagenomes. These data suggest that defense is an important functional trait for an existence within sponges that requires mechanisms to defend against foreign DNA from microorganisms and viruses. This study contributes to an understanding of the evolutionary arms race between viruses/phages and bacterial genomes and it sheds light on the bacterial defenses that have evolved in the context of the sponge holobiont.}, }
@article {pmid27858116, year = {2017}, author = {Lee, HU and McPherson, ZE and Tan, B and Korecka, A and Pettersson, S}, title = {Host-microbiome interactions: the aryl hydrocarbon receptor and the central nervous system.}, journal = {Journal of molecular medicine (Berlin, Germany)}, volume = {95}, number = {1}, pages = {29-39}, doi = {10.1007/s00109-016-1486-0}, pmid = {27858116}, issn = {1432-1440}, mesh = {Animals ; Central Nervous System/*physiology ; Gastrointestinal Microbiome ; Gastrointestinal Tract ; *Host-Pathogen Interactions ; Humans ; Ligands ; *Microbiota ; Neurodegenerative Diseases/etiology/metabolism/pathology ; Neurogenesis ; Receptors, Aryl Hydrocarbon/*metabolism ; *Signal Transduction ; }, abstract = {The microbiome located within a given host and its organs forms a holobiont, an intimate functional entity with evolutionarily designed interactions to support nutritional intake and reproduction. Thus, all organs in a holobiont respond to changes within the microbiome. The development and function of the central nervous system and its homeostatic mechanisms are no exception and are also subject to regulation by the gut microbiome. In order for the holobiont to function effectively, the microbiome and host must communicate. The aryl hydrocarbon receptor is an evolutionarily conserved receptor recognizing environmental compounds, including a number of ligands produced directly and indirectly by the microbiome. This review focuses on the microbiome-gut-brain axis in regard to the aryl hydrocarbon receptor signaling pathway and its impact on underlying mechanisms in neurodegeneration.}, }
@article {pmid27857087, year = {2016}, author = {Kilian, M and Chapple, IL and Hannig, M and Marsh, PD and Meuric, V and Pedersen, AM and Tonetti, MS and Wade, WG and Zaura, E}, title = {The oral microbiome - an update for oral healthcare professionals.}, journal = {British dental journal}, volume = {221}, number = {10}, pages = {657-666}, doi = {10.1038/sj.bdj.2016.865}, pmid = {27857087}, issn = {1476-5373}, mesh = {*Dental Caries ; Humans ; *Microbiota ; Mouth/*microbiology ; *Oral Health ; Periodontitis ; }, abstract = {For millions of years, our resident microbes have coevolved and coexisted with us in a mostly harmonious symbiotic relationship. We are not distinct entities from our microbiome, but together we form a 'superorganism' or holobiont, with the microbiome playing a significant role in our physiology and health. The mouth houses the second most diverse microbial community in the body, harbouring over 700 species of bacteria that colonise the hard surfaces of teeth and the soft tissues of the oral mucosa. Through recent advances in technology, we have started to unravel the complexities of the oral microbiome and gained new insights into its role during both health and disease. Perturbations of the oral microbiome through modern-day lifestyles can have detrimental consequences for our general and oral health. In dysbiosis, the finely-tuned equilibrium of the oral ecosystem is disrupted, allowing disease-promoting bacteria to manifest and cause conditions such as caries, gingivitis and periodontitis. For practitioners and patients alike, promoting a balanced microbiome is therefore important to effectively maintain or restore oral health. This article aims to give an update on our current knowledge of the oral microbiome in health and disease and to discuss implications for modern-day oral healthcare.}, }
@article {pmid27833995, year = {2017}, author = {Thomas, P and Sekhar, AC}, title = {Cultivation Versus Molecular Analysis of Banana (Musa sp.) Shoot-Tip Tissue Reveals Enormous Diversity of Normally Uncultivable Endophytic Bacteria.}, journal = {Microbial ecology}, volume = {73}, number = {4}, pages = {885-899}, doi = {10.1007/s00248-016-0877-7}, pmid = {27833995}, issn = {1432-184X}, mesh = {Bacteria/*classification/*genetics/isolation &amp; purification ; Biodiversity ; Chloroplasts/genetics ; DNA, Bacterial/genetics/isolation &amp; purification ; DNA, Ribosomal/genetics ; Ecosystem ; Endophytes/*classification/*genetics/isolation &amp; purification ; India ; Metagenome ; Metagenomics/methods ; Microbiota ; Mitochondria/genetics ; Musa/*microbiology ; *Phylogeny ; Plant Shoots/*growth &amp; development/*microbiology ; Polymerase Chain Reaction ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Soil Microbiology ; }, abstract = {The interior of plants constitutes a unique environment for microorganisms with various organisms inhabiting as endophytes. Unlike subterranean plant parts, aboveground parts are relatively less explored for endophytic microbial diversity. We employed a combination of cultivation and molecular approaches to study the endophytic bacterial diversity in banana shoot-tips. Cultivable bacteria from 20 sucker shoot-tips of cv. Grand Naine included 37 strains under 16 genera and three phyla (Proteobacteria, Actinobacteria, Firmicutes). 16S rRNA gene-ribotyping approach on 799f and 1492r PCR-amplicons to avoid plant organelle sequences was ineffective showing limited bacterial diversity. 16S rRNA metagene profiling targeting the V3-V4 hypervariable region after filtering out the chloroplast (74.2 %), mitochondrial (22.9 %), and unknown sequences (1.1 %) revealed enormous bacterial diversity. Proteobacteria formed the predominant phylum (64 %) succeeded by Firmicutes (12.1 %), Actinobacteria (9.5 %), Bacteroidetes (6.4 %), Planctomycetes, Cyanobacteria, and minor shares (<1 %) of 14 phyla including several candidate phyla besides the domain Euryarchaeota (0.2 %). Microbiome analysis of single shoot-tips through 16S rRNA V3 region profiling showed similar taxonomic richness and diversity and was less affected by plant sequence interferences. DNA extraction kit ominously influenced the phylogenetic diversity. The study has revealed vast diversity of normally uncultivable endophytic bacteria prevailing in banana shoot-tips (20 phyla, 46 classes) with about 2.6 % of the deciphered 269 genera and 1.5 % of the 656 observed species from the same source of shoot-tips attained through cultivation. The predominant genera included several agriculturally important bacteria. The study reveals an immense ecosystem of endophytic bacteria in banana shoot tissues endorsing the earlier documentation of intracellular &quot;Cytobacts&quot; and &quot;Peribacts&quot; with possible roles in plant holobiome and hologenome.}, }
@article {pmid27822559, year = {2016}, author = {Apprill, A and Weber, LG and Santoro, AE}, title = {Distinguishing between Microbial Habitats Unravels Ecological Complexity in Coral Microbiomes.}, journal = {mSystems}, volume = {1}, number = {5}, pages = {}, doi = {10.1128/mSystems.00143-16}, pmid = {27822559}, issn = {2379-5077}, abstract = {The diverse prokaryotic communities associated with reef-building corals may provide important ecological advantages to their threatened hosts. The consistency of relationships between corals and specific prokaryotes, however, is debated, and the locations where microbially mediated processes occur in the host are not resolved. Here, we examined how the prokaryotic associates of five common Caribbean corals with different evolutionary and ecological traits differ across mucus and tissue habitats. We used physical and chemical separation of coral mucus and tissue and sequencing of partial small-subunit rRNA genes of bacteria and archaea from these samples to demonstrate that coral tissue and mucus harbor unique reservoirs of prokaryotes, with 23 to 49% and 31 to 56% of sequences exclusive to the tissue and mucus habitats, respectively. Across all coral species, we found that 46 tissue- and 22 mucus-specific microbial members consistently associated with the different habitats. Sequences classifying as &quot;Candidatus Amoebophilus,&quot; Bacteroidetes-affiliated intracellular symbionts of amoebae, emerged as previously unrecognized tissue associates of three coral species. This study demonstrates how coral habitat differentiation enables highly resolved examination of ecological interactions between corals and their associated microorganisms and identifies previously unrecognized tissue and mucus associates of Caribbean corals for future targeted study. IMPORTANCE This study demonstrates that coral tissue or mucus habitats structure the microbiome of corals and that separation of these habitats facilitates identification of consistent microbial associates. Using this approach, we demonstrated that sequences related to &quot;Candidatus Amoebophilus,&quot; recognized intracellular symbionts of amoebae, were highly associated with the tissues of Caribbean corals and possibly endosymbionts of a protistan host within corals, adding a further degree of intricacy to coral holobiont symbioses. Examining specific habitats within complex hosts such as corals is useful for targeting important microbial associations that may otherwise be masked by the sheer microbial diversity associated with all host habitats.}, }
@article {pmid27822520, year = {2016}, author = {Theis, KR and Dheilly, NM and Klassen, JL and Brucker, RM and Baines, JF and Bosch, TC and Cryan, JF and Gilbert, SF and Goodnight, CJ and Lloyd, EA and Sapp, J and Vandenkoornhuyse, P and Zilber-Rosenberg, I and Rosenberg, E and Bordenstein, SR}, title = {Getting the Hologenome Concept Right: an Eco-Evolutionary Framework for Hosts and Their Microbiomes.}, journal = {mSystems}, volume = {1}, number = {2}, pages = {}, doi = {10.1128/mSystems.00028-16}, pmid = {27822520}, issn = {2379-5077}, abstract = {Given the complexity of host-microbiota symbioses, scientists and philosophers are asking questions at new biological levels of hierarchical organization-what is a holobiont and hologenome? When should this vocabulary be applied? Are these concepts a null hypothesis for host-microbe systems or limited to a certain spectrum of symbiotic interactions such as host-microbial coevolution? Critical discourse is necessary in this nascent area, but productive discourse requires that skeptics and proponents use the same lexicon. For instance, critiquing the hologenome concept is not synonymous with critiquing coevolution, and arguing that an entity is not a primary unit of selection dismisses the fact that the hologenome concept has always embraced multilevel selection. Holobionts and hologenomes are incontrovertible, multipartite entities that result from ecological, evolutionary, and genetic processes at various levels. They are not restricted to one special process but constitute a wider vocabulary and framework for host biology in light of the microbiome.}, }
@article {pmid27819120, year = {2016}, author = {Li, Z and Wang, Y and Li, J and Liu, F and He, L and He, Y and Wang, S}, title = {Metagenomic Analysis of Genes Encoding Nutrient Cycling Pathways in the Microbiota of Deep-Sea and Shallow-Water Sponges.}, journal = {Marine biotechnology (New York, N.Y.)}, volume = {18}, number = {6}, pages = {659-671}, doi = {10.1007/s10126-016-9725-5}, pmid = {27819120}, issn = {1436-2236}, mesh = {Animals ; Archaea/classification/*genetics/metabolism ; Bacteria/classification/*genetics/metabolism ; Biological Evolution ; Carbon/metabolism ; Fungi/classification/*genetics/metabolism ; High-Throughput Nucleotide Sequencing ; Metabolic Networks and Pathways/genetics ; *Metagenome ; Microbiota/genetics ; Nitrogen/metabolism ; Phosphorus/metabolism ; Phylogeny ; Porifera/classification/genetics/*microbiology ; RNA, Ribosomal, 16S/genetics ; RNA, Ribosomal, 18S/genetics ; RNA, Ribosomal, 28S/genetics ; Stramenopiles/classification/*genetics/metabolism ; Sulfur/metabolism ; Symbiosis/physiology ; }, abstract = {Sponges host complex symbiotic communities, but to date, the whole picture of the metabolic potential of sponge microbiota remains unclear, particularly the difference between the shallow-water and deep-sea sponge holobionts. In this study, two completely different sponges, shallow-water sponge Theonella swinhoei from the South China Sea and deep-sea sponge Neamphius huxleyi from the Indian Ocean, were selected to compare their whole symbiotic communities and metabolic potential, particularly in element transformation. Phylogenetically diverse bacteria, archaea, fungi, and algae were detected in both shallow-water sponge T. swinhoei and deep-sea sponge N. huxleyi, and different microbial community structures were indicated between these two sponges. Metagenome-based gene abundance analysis indicated that, though the two sponge microbiota have similar core functions, they showed different potential strategies in detailed metabolic processes, e.g., in the transformation and utilization of carbon, nitrogen, phosphorus, and sulfur by corresponding microbial symbionts. This study provides insight into the putative metabolic potentials of the microbiota associated with the shallow-water and deep-sea sponges at the whole community level, extending our knowledge of the sponge microbiota's functions, the association of sponge- microbes, as well as the adaption of sponge microbiota to the marine environment.}, }
@article {pmid27818648, year = {2016}, author = {Kopac, SM and Klassen, JL}, title = {Can They Make It on Their Own? Hosts, Microbes, and the Holobiont Niche.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1647}, doi = {10.3389/fmicb.2016.01647}, pmid = {27818648}, issn = {1664-302X}, abstract = {Virtually all multicellular organisms host a community of symbionts composed of mutualistic, commensal, and pathogenic microbes, i.e., their microbiome. The mechanism of selection on host-microbe assemblages remains contentious, particularly regarding whether selection acts differently on hosts and their microbial symbionts. Here, we attempt to reconcile these viewpoints using a model that describes how hosts and their microbial symbionts alter each other's niche and thereby fitness. We describe how host-microbe interactions might change the shape of the host niche and/or reproductive rates within it, which are directly related to host fitness. A host may also alter the niche of a symbiotic microbe, although this depends on the extent to which that microbe is dependent on the host for reproduction. Finally, we provide a mathematical model to test whether interactions between hosts and microbes are necessary to describe the niche of either partner. Our synthesis highlights the phenotypic effects of host-microbe interactions while respecting the unique lifestyles of each partner, and thereby provides a unified framework to describe how selection might act on a host that is associated with its microbiome.}, }
@article {pmid27809267, year = {2016}, author = {Xu, L and Shi, Z and Wang, B and Lu, M and Sun, J}, title = {Pine Defensive Monoterpene α-Pinene Influences the Feeding Behavior of Dendroctonus valens and Its Gut Bacterial Community Structure.}, journal = {International journal of molecular sciences}, volume = {17}, number = {11}, pages = {}, doi = {10.3390/ijms17111734}, pmid = {27809267}, issn = {1422-0067}, mesh = {Animals ; Bacteria/classification/genetics ; Coleoptera/*drug effects/microbiology/physiology ; DNA, Bacterial/chemistry/genetics ; Dose-Response Relationship, Drug ; Feeding Behavior/*drug effects ; Gastrointestinal Microbiome/*drug effects/genetics/physiology ; Genetic Variation ; Host-Pathogen Interactions/drug effects ; Monoterpenes/*pharmacology ; Phloem/chemistry ; Pinus/*chemistry ; Polymerase Chain Reaction ; Principal Component Analysis ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Time Factors ; }, abstract = {The exposure to plant defense chemicals has negative effects on insect feeding activity and modifies insect gut microbial community composition. Dendroctonus valens is a very destructive forest pest in China, and harbors a large diversity and abundance of gut microorganisms. Host pine defensive chemicals can protect the pines from attack by the holobiont. In this study, boring length of D. valens feeding on 0 mg/g α-pinene and 9 mg/g α-pinene concentration in phloem media for 6 and 48 h were recorded, and their gut bacterial communities were analyzed in parallel. Nine milligram per gram α-pinene concentration significantly inhibited boring length of D. valens and altered its gut microbial community structure after 6 h. The inhibition of boring length from 9 mg/g α-pinene in diets ceased after 48 h. No significant differences of the bacterial communities were observed between the beetles in 0 and 9 mg/g α-pinene concentration in phloem media after 48 h. Our results showed that the inhibition of the feeding behavior of D. valens and the disturbance to its gut bacterial communities in 9 mg/g α-pinene concentration in phloem media after 6 h were eliminated after 48 h. The resilience of gut bacterial community of D. valens may help the beetle catabolize pine defense chemical.}, }
@article {pmid27803185, year = {2016}, author = {Schröder, K and Bosch, TC}, title = {The Origin of Mucosal Immunity: Lessons from the Holobiont Hydra.}, journal = {mBio}, volume = {7}, number = {6}, pages = {}, doi = {10.1128/mBio.01184-16}, pmid = {27803185}, issn = {2150-7511}, mesh = {Animals ; *Biological Evolution ; Hydra/*immunology ; *Immunity, Innate ; *Immunity, Mucosal ; Models, Animal ; Vertebrates/*immunology ; }, abstract = {Historically, mucosal immunity-i.e., the portion of the immune system that protects an organism's various mucous membranes from invasion by potentially pathogenic microbes-has been studied in single-cell epithelia in the gastrointestinal and upper respiratory tracts of vertebrates. Phylogenetically, mucosal surfaces appeared for the first time about 560 million years ago in members of the phylum Cnidaria. There are remarkable similarities and shared functions of mucosal immunity in vertebrates and innate immunity in cnidarians, such as Hydra species. Here, we propose a common origin for both systems and review observations that indicate that the ultimately simple holobiont Hydra provides both a new perspective on the relationship between bacteria and animal cells and a new prism for viewing the emergence and evolution of epithelial tissue-based innate immunity. In addition, recent breakthroughs in our understanding of immune responses in Hydra polyps reared under defined short-term gnotobiotic conditions open up the potential of Hydra as an animal research model for the study of common mucosal disorders.}, }
@article {pmid27799924, year = {2016}, author = {Berg, M and Zhou, XY and Shapira, M}, title = {Host-Specific Functional Significance of Caenorhabditis Gut Commensals.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1622}, doi = {10.3389/fmicb.2016.01622}, pmid = {27799924}, issn = {1664-302X}, support = {S10 RR027303/RR/NCRR NIH HHS/United States ; S10 RR029668/RR/NCRR NIH HHS/United States ; }, abstract = {The gut microbiota is an important contributor to host health and fitness. Given its importance, microbiota composition should not be left to chance. However, what determines this composition is far from clear, with results supporting contributions of both environmental factors and host genetics. To gauge the relative contributions of host genetics and environment, specifically the microbial diversity, we characterized the gut microbiotas of Caenorhabditis species spanning 200-300 million years of evolution, and raised on different composted soil environments. Comparisons were based on 16S rDNA deep sequencing data, as well as on functional evaluation of gut isolates. Worm microbiotas were distinct from those in their respective soil environment, and included bacteria previously identified as part of the C. elegans core microbiota. Microbiotas differed between experiments initiated with different soil communities, but within each experiment, worm microbiotas clustered according to host identity, demonstrating a dominant contribution of environmental diversity, but also a significant contribution of host genetics. The dominance of environmental contributions hindered identification of host-associated microbial taxa from 16S data. Characterization of gut isolates from C. elegans and C. briggsae, focusing on the core family Enterobacteriaceae, were also unable to expose phylogenetic distinctions between microbiotas of the two species. However, functional evaluation of the isolates revealed host-specific contributions, wherein gut commensals protected their own host from infection, but not a non-host. Identification of commensal host-specificity at the functional level, otherwise overlooked in standard sequence-based analyses, suggests that the contribution of host genetics to shaping of gut microbiotas may be greater than previously realized.}, }
@article {pmid27795310, year = {2017}, author = {Morrow, KM and Bromhall, K and Motti, CA and Munn, CB and Bourne, DG}, title = {Allelochemicals Produced by Brown Macroalgae of the Lobophora Genus Are Active against Coral Larvae and Associated Bacteria, Supporting Pathogenic Shifts to Vibrio Dominance.}, journal = {Applied and environmental microbiology}, volume = {83}, number = {1}, pages = {}, doi = {10.1128/AEM.02391-16}, pmid = {27795310}, issn = {1098-5336}, mesh = {Animals ; Anthozoa/drug effects/*microbiology ; Archaea/drug effects/genetics/growth &amp; development/isolation &amp; purification ; Bacteria/drug effects/genetics/growth &amp; development/pathogenicity ; Coral Reefs ; Ecosystem ; Larva/drug effects ; Metagenomics ; Microbial Consortia/drug effects/genetics ; Microbiota/*drug effects/genetics ; Phaeophyta/*chemistry/physiology ; Pheromones/biosynthesis/chemistry/*pharmacology ; Population Dynamics ; RNA, Ribosomal, 16S ; Seaweed/chemistry/growth &amp; development/*physiology ; Vibrio/*isolation &amp; purification/pathogenicity/physiology ; }, abstract = {Pervasive environmental stressors on coral reefs are attributed with shifting the competitive balance in favor of alternative dominants, such as macroalgae. Previous studies have demonstrated that macroalgae compete with corals via a number of mechanisms, including the production of potent primary and secondary metabolites that can influence coral-associated microbial communities. The present study investigates the effects of the Pacific brown macroalga Lobophora sp. (due to the shifting nature of the Lobophora species complex, it will be referred to here as Lobophora sp.) on coral bacterial isolates, coral larvae, and the microbiome associated with the coral Porites cylindrica. Crude aqueous and organic macroalgal extracts were found to inhibit the growth of coral-associated bacteria. Extracts and fractions were also shown to inhibit coral larval settlement and cause mortality at concentrations lower (<0.3 mg · ml-1) than calculated natural concentrations (4.4 mg · ml-1). Microbial communities associated with coral tissues exposed to aqueous (e.g., hydrophilic) crude extracts demonstrated a significant shift to Vibrio dominance and a loss of sequences related to the putative coral bacterial symbiont, Endozoicomonas sp., based on 16S rRNA amplicon sequencing. This study contributes to growing evidence that macroalgal allelochemicals, dissolved organic material, and native macroalgal microbial assemblages all play a role in shifting the microbial equilibrium of the coral holobiont away from a beneficial state, contributing to a decline in coral fitness and a shift in ecosystem structure.<br><br>IMPORTANCE: Diverse microbial communities associate with coral tissues and mucus, providing important protective and nutritional services, but once disturbed, the microbial equilibrium may shift from a beneficial state to one that is detrimental or pathogenic. Macroalgae (e.g., seaweeds) can physically and chemically interact with corals, causing abrasion, bleaching, and overall stress. This study contributes to a growing body of evidence suggesting that macroalgae play a critical role in shifting the coral holobiont equilibrium, which may promote the invasion of opportunistic pathogens and cause coral mortality, facilitating additional macroalgal growth and invasion in the reef. Thus, macroalgae not only contribute to a decline in coral fitness but also influence coral reef ecosystem structure.}, }
@article {pmid27594308, year = {2016}, author = {Root-Bernstein, R}, title = {Autoimmunity and the microbiome: T-cell receptor mimicry of &quot;self&quot; and microbial antigens mediates self tolerance in holobionts: The concepts of &quot;holoimmunity&quot; (TcR-mediated tolerance for the holobiont) and &quot;holoautoimmunity&quot; (loss of tolerance for the holobiont) are introduced.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {38}, number = {11}, pages = {1068-1083}, doi = {10.1002/bies.201600083}, pmid = {27594308}, issn = {1521-1878}, mesh = {*Autoimmunity ; Humans ; Immune Tolerance ; Microbiota/*immunology ; Receptors, Antigen, T-Cell/*immunology ; }, abstract = {I propose a T-cell receptor (TcR)-based mechanism by which immunity mediates both &quot;genetic self&quot; and &quot;microbial self&quot; thereby, connecting microbiome disease with autoimmunity. The hypothesis is based on simple principles. First, TcR are selected to avoid strong cross-reactivity with &quot;self,&quot; resulting in selection for a TcR repertoire mimicking &quot;genetic self.&quot; Second, evolution has selected for a &quot;microbial self&quot; that mimics &quot;genetic self&quot; so as to share tolerance. In consequence, our TcR repertoire also mimics microbiome antigenicity, providing a novel mechanism for modulating tolerance to it. Also, the microbiome mimics the TcR repertoire, acting as a secondary immune system. I call this TcR-microbiome mimicry &quot;holoimmunity&quot; to denote immune tolerance to the &quot;holobiont self.&quot; Logically, microbiome-host mimicry means that autoimmunity directed at host antigens will also attack components of the microbiome, and conversely, an immunological attack on the microbiome may cross-react with host antigens producing &quot;holoautoimmunity.&quot;}, }
@article {pmid27777745, year = {2016}, author = {Aichelman, HE and Townsend, JE and Courtney, TA and Baumann, JH and Davies, SW and Castillo, KD}, title = {Heterotrophy mitigates the response of the temperate coral Oculina arbuscula to temperature stress.}, journal = {Ecology and evolution}, volume = {6}, number = {18}, pages = {6758-6769}, doi = {10.1002/ece3.2399}, pmid = {27777745}, issn = {2045-7758}, abstract = {Anthropogenic increases in atmospheric carbon dioxide concentration have caused global average sea surface temperature (SST) to increase by approximately 0.11°C per decade between 1971 and 2010 - a trend that is projected to continue through the 21st century. A multitude of research studies have demonstrated that increased SSTs compromise the coral holobiont (cnidarian host and its symbiotic algae) by reducing both host calcification and symbiont density, among other variables. However, we still do not fully understand the role of heterotrophy in the response of the coral holobiont to elevated temperature, particularly for temperate corals. Here, we conducted a pair of independent experiments to investigate the influence of heterotrophy on the response of the temperate scleractinian coral Oculina arbuscula to thermal stress. Colonies of O. arbuscula from Radio Island, North Carolina, were exposed to four feeding treatments (zero, low, moderate, and high concentrations of newly hatched Artemia sp. nauplii) across two independent temperature experiments (average annual SST (20°C) and average summer temperature (28°C) for the interval 2005-2012) to quantify the effects of heterotrophy on coral skeletal growth and symbiont density. Results suggest that heterotrophy mitigated both reduced skeletal growth and decreased symbiont density observed for unfed corals reared at 28°C. This study highlights the importance of heterotrophy in maintaining coral holobiont fitness under thermal stress and has important implications for the interpretation of coral response to climate change.}, }
@article {pmid27726033, year = {2017}, author = {van de Water, JA and Melkonian, R and Voolstra, CR and Junca, H and Beraud, E and Allemand, D and Ferrier-Pagès, C}, title = {Comparative Assessment of Mediterranean Gorgonian-Associated Microbial Communities Reveals Conserved Core and Locally Variant Bacteria.}, journal = {Microbial ecology}, volume = {73}, number = {2}, pages = {466-478}, doi = {10.1007/s00248-016-0858-x}, pmid = {27726033}, issn = {1432-184X}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/*classification/genetics/isolation &amp; purification ; Base Sequence ; Biodiversity ; Classification ; Coral Reefs ; DNA, Bacterial/genetics ; Gene Library ; Mediterranean Sea ; *Microbiota/genetics ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Seasons ; Seawater/microbiology ; Species Specificity ; Temperature ; }, abstract = {Gorgonians are key habitat-forming species of Mediterranean benthic communities, but their populations have suffered from mass mortality events linked to high summer seawater temperatures and microbial disease. However, our knowledge on the diversity, dynamics and function of gorgonian-associated microbial communities is limited. Here, we analysed the spatial variability of the microbiomes of five sympatric gorgonian species (Eunicella singularis, Eunicella cavolini, Eunicella verrucosa, Leptogorgia sarmentosa and Paramuricea clavata), collected from the Mediterranean Sea over a scale of ∼1100 km, using next-generation amplicon sequencing of the 16S rRNA gene. The microbiomes of all gorgonian species were generally dominated by members of the genus Endozoicomonas, which were at very low abundance in the surrounding seawater. Although the composition of the core microbiome (operational taxonomic units consistently present in a species) was found to be unique for each host species, significant overlap was observed. These spatially consistent associations between gorgonians and their core bacteria suggest intricate symbiotic relationships and regulation of the microbiome composition by the host. At the same time, local variations in microbiome composition were observed. Functional predictive profiling indicated that these differences could be attributed to seawater pollution. Taken together, our data indicate that gorgonian-associated microbiomes are composed of spatially conserved bacteria (core microbiome members) and locally variant members, and that local pollution may influence these local associations, potentially impacting gorgonian health.}, }
@article {pmid27721807, year = {2016}, author = {Dittmer, J and van Opstal, EJ and Shropshire, JD and Bordenstein, SR and Hurst, GD and Brucker, RM}, title = {Disentangling a Holobiont - Recent Advances and Perspectives in Nasonia Wasps.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1478}, doi = {10.3389/fmicb.2016.01478}, pmid = {27721807}, issn = {1664-302X}, abstract = {The parasitoid wasp genus Nasonia (Hymenoptera: Chalcidoidea) is a well-established model organism for insect development, evolutionary genetics, speciation, and symbiosis. The host-microbiota assemblage which constitutes the Nasonia holobiont (a host together with all of its associated microbes) consists of viruses, two heritable bacterial symbionts and a bacterial community dominated in abundance by a few taxa in the gut. In the wild, all four Nasonia species are systematically infected with the obligate intracellular bacterium Wolbachia and can additionally be co-infected with Arsenophonus nasoniae. These two reproductive parasites have different transmission modes and host manipulations (cytoplasmic incompatibility vs. male-killing, respectively). Pioneering studies on Wolbachia in Nasonia demonstrated that closely related Nasonia species harbor multiple and mutually incompatible Wolbachia strains, resulting in strong symbiont-mediated reproductive barriers that evolved early in the speciation process. Moreover, research on host-symbiont interactions and speciation has recently broadened from its historical focus on heritable symbionts to the entire microbial community. In this context, each Nasonia species hosts a distinguishable community of gut bacteria that experiences a temporal succession during host development and members of this bacterial community cause strong hybrid lethality during larval development. In this review, we present the Nasonia species complex as a model system to experimentally investigate questions regarding: (i) the impact of different microbes, including (but not limited to) heritable endosymbionts, on the extended phenotype of the holobiont, (ii) the establishment and regulation of a species-specific microbiota, (iii) the role of the microbiota in speciation, and (iv) the resilience and adaptability of the microbiota in wild populations subjected to different environmental pressures. We discuss the potential for easy microbiota manipulations in Nasonia as a promising experimental approach to address these fundamental aspects.}, }
@article {pmid27716053, year = {2016}, author = {Peterson, BF and Scharf, ME}, title = {Metatranscriptome analysis reveals bacterial symbiont contributions to lower termite physiology and potential immune functions.}, journal = {BMC genomics}, volume = {17}, number = {1}, pages = {772}, doi = {10.1186/s12864-016-3126-z}, pmid = {27716053}, issn = {1471-2164}, mesh = {Amidohydrolases/genetics/metabolism ; Animals ; Antibiosis ; Bacteria/*genetics ; Computational Biology/methods ; Fungi/physiology ; Gene Expression Profiling ; Genes, rRNA ; Glutathione Transferase/metabolism ; Isoptera/*immunology/metabolism/*microbiology ; *Metagenome ; *Metagenomics/methods ; Oxidative Stress ; Reactive Oxygen Species/metabolism ; Reproducibility of Results ; *Symbiosis ; *Transcriptome ; }, abstract = {BACKGROUND: Symbioses throughout the animal kingdom are known to extend physiological and ecological capabilities to hosts. Insect-microbe associations are extremely common and are often related to novel niche exploitation, fitness advantages, and even speciation events. These phenomena include expansions in host diet, detoxification of insecticides and toxins, and increased defense against pathogens. However, dissecting the contributions of individual groups of symbionts at the molecular level is often underexplored due to methodological and analytical limitations. Termites are one of the best studied systems for physiological collaborations between host and symbiota; however, most work in lower termites (those with bacterial and protist symbionts) focuses on the eukaryotic members of this symbiotic consortium. Here we present a metatranscriptomic analysis which provides novel insights into bacterial contributions to the holobiont of the eastern subterranean termite, Reticulitermes flavipes, in the presence and absence of a fungal pathogen.<br><br>RESULTS: Using a customized ribodepletion strategy, a metatranscriptome assembly was obtained representing the host termite as well as bacterial and protist symbiota. Sequence data provide new insights into biosynthesis, catabolism, and transport of major organic molecules and ions by the gut consortium, and corroborate previous findings suggesting that bacteria play direct roles in nitrogen fixation, amino acid biosynthesis, and lignocellulose digestion. With regard to fungal pathogen challenge, a total of 563 differentially expressed candidate host and symbiont contigs were identified (162 up- and 401 downregulated; α/FDR = 0.05) including an upregulated bacterial amidohydrolase.<br><br>CONCLUSIONS: This study presents the most complete bacterial metatranscriptome from a lower termite and provides a framework on which to build a more complete model of termite-symbiont interactions including, but not limited to, digestion and pathogen defense.}, }
@article {pmid27708547, year = {2016}, author = {Torday, JS and Miller, WB}, title = {Life is determined by its environment.}, journal = {International journal of astrobiology}, volume = {15}, number = {4}, pages = {345-350}, doi = {10.1017/S1473550415000567}, pmid = {27708547}, issn = {1473-5504}, support = {R01 HL055268/HL/NHLBI NIH HHS/United States ; //United States NHLBI/ ; }, abstract = {A well-developed theory of evolutionary biology requires understanding of the origins of life on Earth. However, the initial conditions (ontology) and causal (epistemology) bases on which physiology proceeded have more recently been called into question, given the teleologic nature of Darwinian evolutionary thinking. When evolutionary development is focused on cellular communication, a distinctly different perspective unfolds. The cellular communicative-molecular approach affords a logical progression for the evolutionary narrative based on the basic physiologic properties of the cell. Critical to this appraisal is recognition of the cell as a fundamental reiterative unit of reciprocating communication that receives information from and reacts to epiphenomena to solve problems. Following the course of vertebrate physiology from its unicellular origins instead of its overt phenotypic appearances and functional associations provides a robust, predictive picture for the means by which complex physiology evolved from unicellular organisms. With this foreknowledge of physiologic principles, we can determine the fundamentals of Physiology based on cellular first principles using a logical, predictable method. Thus, evolutionary creativity on our planet can be viewed as a paradoxical product of boundary conditions that permit homeostatic moments of varying length and amplitude that can productively absorb a variety of epigenetic impacts to meet environmental challenges.}, }
@article {pmid27690269, year = {2016}, author = {McIlroy, SE and Gillette, P and Cunning, R and Klueter, A and Capo, T and Baker, AC and Coffroth, MA}, title = {The effects of Symbiodinium (Pyrrhophyta) identity on growth, survivorship, and thermal tolerance of newly settled coral recruits.}, journal = {Journal of phycology}, volume = {52}, number = {6}, pages = {1114-1124}, doi = {10.1111/jpy.12471}, pmid = {27690269}, issn = {1529-8817}, mesh = {Animals ; Anthozoa/growth &amp; development/*physiology ; Dinoflagellida/*physiology ; Florida ; Species Specificity ; *Symbiosis ; *Thermotolerance ; }, abstract = {For many coral species, the obligate association with phylogenetically diverse algal endosymbiont species is dynamic in time and space. Here, we used controlled laboratory inoculations of newly settled, aposymbiotic corals (Orbicella faveolata) with two cultured species of algal symbiont (Symbiodinium microadriaticum and S. minutum) to examine the role of symbiont identity on growth, survivorship, and thermal tolerance of the coral holobiont. We evaluated these data in the context of Symbiodinium photophysiology for 9 months post-settlement and also during a 5-d period of elevated temperatures Our data show that recruits that were inoculated with S. minutum grew significantly slower than those inoculated with S. microadriaticum (occasionally co-occurring with S. minutum), but that there was no difference in survivorship of O. faveolata polyps infected with Symbiodinium. However, photophysiological metrics (∆Fv/F'm, the efficiency with which available light is used to drive photosynthesis and α, the maximum light utilization coefficient) were higher in those slower growing recruits containing S. minutum. These findings suggest that light use (i.e., photophysiology) and carbon acquisition by the coral host (i.e., host growth) are decoupled, but did not distinguish the source of this difference. Neither Symbiodinium treatment demonstrated a significant negative effect of a 5-d exposure to temperatures as high as 32°C under low light conditions similar to those measured at settlement habitats.}, }
@article {pmid27690185, year = {2016}, author = {Rubio-Portillo, E and Santos, F and Martínez-García, M and de Los Ríos, A and Ascaso, C and Souza-Egipsy, V and Ramos-Esplá, AA and Anton, J}, title = {Structure and temporal dynamics of the bacterial communities associated to microhabitats of the coral Oculina patagonica.}, journal = {Environmental microbiology}, volume = {18}, number = {12}, pages = {4564-4578}, doi = {10.1111/1462-2920.13548}, pmid = {27690185}, issn = {1462-2920}, mesh = {Animals ; Anthozoa/*microbiology ; Denaturing Gradient Gel Electrophoresis ; Ecosystem ; Mediterranean Sea ; Vibrio/isolation &amp; purification/physiology ; }, abstract = {Corals are known to contain a diverse microbiota that plays a paramount role in the physiology and health of holobiont. However, few studies have addressed the variability of bacterial communities within the coral host. In this study, bacterial community composition from the mucus, tissue and skeleton of the scleractinian coral Oculina patagonica were investigated seasonally at two locations in the Western Mediterranean Sea, to further understand how environmental conditions and the coral microbiome structure are related. We used denaturing gradient gel electrophoresis in combination with next-generation sequencing and electron microscopy to characterize the bacterial community. The bacterial communities were significantly different among coral compartments, and coral tissue displayed the greatest changes related to environmental conditions and coral health status. Species belonging to the Rhodobacteraceae and Vibrionaceae families form part of O. patagonica tissues core microbiome and may play significant roles in the nitrogen cycle. Furthermore, sequences related to the coral pathogens, Vibrio mediterranei and Vibrio coralliilyticus, were detected not only in bleached corals but also in healthy ones, even during cold months. This fact opens a new view onto unveiling the role of pathogens in the development of coral diseases in the future.}, }
@article {pmid27688961, year = {2016}, author = {Wada, N and Pollock, FJ and Willis, BL and Ainsworth, T and Mano, N and Bourne, DG}, title = {In situ visualization of bacterial populations in coral tissues: pitfalls and solutions.}, journal = {PeerJ}, volume = {4}, number = {}, pages = {e2424}, doi = {10.7717/peerj.2424}, pmid = {27688961}, issn = {2167-8359}, abstract = {In situ visualization of microbial communities within their natural habitats provides a powerful approach to explore complex interactions between microorganisms and their macroscopic hosts. Specifically, the application of fluorescence in situ hybridization (FISH) to simultaneously identify and visualize diverse microbial taxa associated with coral hosts, including symbiotic algae (Symbiodinium), Bacteria, Archaea, Fungi and protists, could help untangle the structure and function of these diverse taxa within the coral holobiont. However, the application of FISH approaches to coral samples is constrained by non-specific binding of targeted rRNA probes to cellular structures within the coral animal tissues (including nematocysts, spirocysts, granular gland cells within the gastrodermis and cnidoglandular bands of mesenterial filaments). This issue, combined with high auto-fluorescence of both host tissues and endosymbiotic dinoflagellates (Symbiodinium), make FISH approaches for analyses of coral tissues challenging. Here we outline the major pitfalls associated with applying FISH to coral samples and describe approaches to overcome these challenges.}, }
@article {pmid27668211, year = {2016}, author = {Miller, WB}, title = {The Eukaryotic Microbiome: Origins and Implications for Fetal and Neonatal Life.}, journal = {Frontiers in pediatrics}, volume = {4}, number = {}, pages = {96}, doi = {10.3389/fped.2016.00096}, pmid = {27668211}, issn = {2296-2360}, abstract = {All eukaryotic organisms are holobionts representing complex collaborations between the entire microbiome of each eukaryote and its innate cells. These linked constituencies form complex localized and interlocking ecologies in which the specific microbial constituents and their relative abundance differ substantially according to age and environmental exposures. Rapid advances in microbiology and genetic research techniques have uncovered a significant previous underestimate of the extent of that microbial contribution and its metabolic and developmental impact on holobionts. Therefore, a re-calibration of the neonatal period is suggested as a transitional phase in development that includes the acquisition of consequential collaborative microbial life from extensive environmental influences. These co-dependent, symbiotic relationships formed in the fetal and neonatal stages extend into adulthood and even across generations.}, }
@article {pmid27643794, year = {2016}, author = {Ueda, Y and Frindte, K and Knief, C and Ashrafuzzaman, M and Frei, M}, title = {Effects of Elevated Tropospheric Ozone Concentration on the Bacterial Community in the Phyllosphere and Rhizoplane of Rice.}, journal = {PloS one}, volume = {11}, number = {9}, pages = {e0163178}, doi = {10.1371/journal.pone.0163178}, pmid = {27643794}, issn = {1932-6203}, mesh = {Bacteria/genetics/*metabolism ; Oryza/*metabolism/microbiology ; Ozone/*metabolism ; RNA, Ribosomal, 16S/genetics ; }, abstract = {Microbes constitute a vital part of the plant holobiont. They establish plant-microbe or microbe-microbe associations, forming a unique microbiota with each plant species and under different environmental conditions. These microbial communities have to adapt to diverse environmental conditions, such as geographical location, climate conditions and soil types, and are subjected to changes in their surrounding environment. Elevated ozone concentration is one of the most important aspects of global change, but its effect on microbial communities living on plant surfaces has barely been investigated. In the current study, we aimed at elucidating the potential effect of elevated ozone concentrations on the phyllosphere (aerial part of the plant) and rhizoplane (surface of the root) microbiota by adopting next-generation 16S rRNA amplicon sequencing. A standard japonica rice cultivar Nipponbare and an ozone-tolerant breeding line L81 (Nipponbare background) were pre-grown in a greenhouse for 10 weeks and then exposed to ozone at 85 ppb for 7 h daily for 30 days in open top chambers. Microbial cells were collected from the phyllosphere and rhizoplane separately. The treatment or different genotypes did not affect various diversity indices. On the other hand, the relative abundance of some bacterial taxa were significantly affected in the rhizoplane community of ozone-treated plants. A significant effect of ozone was detected by homogeneity of molecular variance analysis in the phyllosphere, meaning that the community from ozone-treated phyllosphere samples was more variable than those from control plants. In addition, a weak treatment effect was observed by clustering samples based on the Yue and Clayton and weighted UniFrac distance matrices among samples. We therefore conclude that the elevated ozone concentrations affected the bacterial community structure of the phyllosphere and the rhizosplane as a whole, even though this effect was rather weak and did not lead to changes of the function of the communities.}, }
@article {pmid27630618, year = {2016}, author = {Francino, MP and Medina, M}, title = {Editorial: Recent Advances in Symbiosis Research: Integrative Approaches.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1331}, doi = {10.3389/fmicb.2016.01331}, pmid = {27630618}, issn = {1664-302X}, }
@article {pmid27617200, year = {2016}, author = {Burcelin, R}, title = {Gut microbiota and immune crosstalk in metabolic disease.}, journal = {Molecular metabolism}, volume = {5}, number = {9}, pages = {771-781}, doi = {10.1016/j.molmet.2016.05.016}, pmid = {27617200}, issn = {2212-8778}, abstract = {BACKGROUND: Gut microbiota is considered as a major regulator of metabolic disease. This reconciles the notion of metabolic inflammation and the epidemic development of the disease. In addition to evidence showing that a specific gut microbiota characterizes patients with obesity, type 2 diabetes, and hepatic steatosis, the mechanisms causal to the disease could be related to the translocation of microbiota from the gut to the tissues, inducing inflammation. The mechanisms regulating such a process are based on the crosstalk between the gut microbiota and the host immune system. The hologenome theory of evolution supports this concept and implies that therapeutic strategies aiming to control glycemia should take into account both the gut microbiota and the host immune system.<br><br>SCOPE OF REVIEW: This review discusses the latest evidence regarding the bidirectional impact of the gut microbiota on host immune system crosstalk for the control of metabolic disease, hyperglycemia, and obesity. To avoid redundancies with the literature, we will focus our attention on the intestinal immune system, identifying evidence for the generation of novel therapeutic strategies, which could be based on the control of the translocation of gut bacteria to tissues. Such novel strategies should hamper the role played by gut microbiota dysbiosis on the development of metabolic inflammation.<br><br>MAJOR CONCLUSIONS: Recent evidence in rodents allows us to conclude that an impaired intestinal immune system characterizes and could be causal in the development of metabolic disease. The fine understanding of the molecular mechanisms should allow for the development of a first line of treatment for metabolic disease and its co-morbidities. This article is part of a special issue on microbiota.}, }
@article {pmid27602023, year = {2016}, author = {Hahn, MA and Dheilly, NM}, title = {Experimental Models to Study the Role of Microbes in Host-Parasite Interactions.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1300}, doi = {10.3389/fmicb.2016.01300}, pmid = {27602023}, issn = {1664-302X}, abstract = {Until recently, parasitic infections have been primarily studied as interactions between the parasite and the host, leaving out crucial players: microbes. The recent realization that microbes play key roles in the biology of all living organisms is not only challenging our understanding of host-parasite evolution, but it also provides new clues to develop new therapies and remediation strategies. In this paper we provide a review of promising and advanced experimental organismal systems to examine the dynamic of host-parasite-microbe interactions. We address the benefits of developing new experimental models appropriate to this new research area and identify systems that offer the best promises considering the nature of the interactions among hosts, parasites, and microbes. Based on these systems, we identify key criteria for selecting experimental models to elucidate the fundamental principles of these complex webs of interactions. It appears that no model is ideal and that complementary studies should be performed on different systems in order to understand the driving roles of microbes in host and parasite evolution.}, }
@article {pmid27581522, year = {2016}, author = {Rouco, M and Haley, ST and Dyhrman, ST}, title = {Microbial diversity within the Trichodesmium holobiont.}, journal = {Environmental microbiology}, volume = {18}, number = {12}, pages = {5151-5160}, doi = {10.1111/1462-2920.13513}, pmid = {27581522}, issn = {1462-2920}, mesh = {*Biodiversity ; Nitrogen/metabolism ; Nitrogen Fixation ; Oceans and Seas ; Phylogeny ; Seawater/*microbiology ; Trichodesmium/classification/genetics/*isolation &amp; purification/metabolism ; }, abstract = {Nitrogen-fixing cyanobacteria in the genus Trichodesmium play a critical role in the productivity of the tropical and subtropical oligotrophic oceans. The ecological success of these populations is likely associated with the diverse microbial interactions occurring within the Trichodesmium holobiont, especially between Trichodesmium and heterotrophic bacterial epibionts. Yet, the composition of the Trichodesmium holobiont and the processes governing microbial assemblage are not well documented. Here, we used high-resolution 16S rDNA amplicon sequencing to examine the diversity of Trichodesmium and associated epibionts across different ocean regions and colony morphologies (puffs and rafts). Trichodesmium Clade I (i.e., T. thiebautii-like) dominated the colonies in all ocean basins regardless of morphology, although the Trichodesmium community structure significantly varied between morphologies in some regions. On average, Alphaproteobacteria (i.e., Thalassobius), Gammaproteobacteria (i.e., Pseudoalteromonas), Sphingobacteria (i.e., Microscilla and Vibrio) and Flavobacteria dominated the epibiont communities, but community composition and structure significantly differed between regions. Epibionts from the two colony morphologies were taxonomically and functionally distinct in the North Atlantic and North Pacific. These findings suggest that the colony types might define two distinct niches and that epibiont assemblage might be driven in part by selective processes, where epibionts are selected according to their influence on colony metabolism.}, }
@article {pmid27507098, year = {2016}, author = {Schnorr, SL and Sankaranarayanan, K and Lewis, CM and Warinner, C}, title = {Insights into human evolution from ancient and contemporary microbiome studies.}, journal = {Current opinion in genetics &amp; development}, volume = {41}, number = {}, pages = {14-26}, doi = {10.1016/j.gde.2016.07.003}, pmid = {27507098}, issn = {1879-0380}, support = {R01 GM089886/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; *Ecology ; *Evolution, Molecular ; Humans ; Microbiota/*genetics ; Primates/genetics/*microbiology ; }, abstract = {Over the past decade, human microbiome research has energized the study of human evolution through a complete shift in our understanding of what it means to be human. The microbiome plays a pivotal role in human biology, performing key functions in digestion, mood and behavior, development and immunity, and a range of acute and chronic diseases. It is therefore critical to understand its evolution and changing ecology through time. Here we review recent findings on the microbiota of diverse human populations, non-human primates, and past human populations and discuss the implications of this research in formulating a deeper evolutionary understanding of the human holobiont.}, }
@article {pmid27492757, year = {2016}, author = {Garcia, GD and Santos, Ede O and Sousa, GV and Zingali, RB and Thompson, CC and Thompson, FL}, title = {Metaproteomics reveals metabolic transitions between healthy and diseased stony coral Mussismilia braziliensis.}, journal = {Molecular ecology}, volume = {25}, number = {18}, pages = {4632-4644}, doi = {10.1111/mec.13775}, pmid = {27492757}, issn = {1365-294X}, mesh = {Animals ; Anthozoa/*genetics/*microbiology ; Bacteria/*classification ; Brazil ; Proteomics ; Symbiosis ; Tandem Mass Spectrometry ; }, abstract = {Infectious diseases such as white plague syndrome (WPS) and black band disease (BBD) have caused massive coral loss worldwide. We performed a metaproteomic study on the Abrolhos coral Mussismilia braziliensis to define the types of proteins expressed in healthy corals compared to WPS- and BBD-affected corals. A total of 6363 MS/MS spectra were identified as 361 different proteins. Healthy corals had a set of proteins that may be considered markers of holobiont homoeostasis, including tubulin, histone, Rab family, ribosomal, peridinin-chlorophyll a-binding protein, F0F1-type ATP synthase, alpha-iG protein, calmodulin and ADP-ribosylation factor. Cnidaria proteins found in healthy M. braziliensis were associated with Cnidaria-Symbiodinium endosymbiosis and included chaperones (hsp70, hsp90 and calreticulin), structural and membrane modelling proteins (actin) and proteins with functions related to intracellular vesicular traffic (Rab7 and ADP-ribosylation factor 1) and signal transduction (14-3-3 protein and calmodulin). WPS resulted in a clear shift in the predominance of proteins, from those related to aerobic nitrogen-fixing bacteria (i.e. Rhizobiales, Sphingomonadales and Actinomycetales) in healthy corals to those produced by facultative/anaerobic sulphate-reducing bacteria (i.e. Enterobacteriales, Alteromonadales, Clostridiales and Bacteroidetes) in WPS corals. BBD corals developed a diverse community dominated by cyanobacteria and sulphur cycle bacteria. Hsp60, hsp90 and adenosylhomocysteinase proteins were produced mainly by cyanobacteria in BBD corals, which is consistent with elevated oxidative stress in hydrogen sulphide- and cyanotoxin-rich environments. This study demonstrates the usefulness of metaproteomics for gaining better comprehension of coral metabolic status in health and disease, especially in reef systems such as the Abrolhos that are suffering from the increase in global and local threatening events.}, }
@article {pmid27486438, year = {2016}, author = {Seston, SL and Beinart, RA and Sarode, N and Shockey, AC and Ranjan, P and Ganesh, S and Girguis, PR and Stewart, FJ}, title = {Metatranscriptional Response of Chemoautotrophic Ifremeria nautilei Endosymbionts to Differing Sulfur Regimes.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {1074}, doi = {10.3389/fmicb.2016.01074}, pmid = {27486438}, issn = {1664-302X}, abstract = {Endosymbioses between animals and chemoautotrophic bacteria are ubiquitous at hydrothermal vents. These environments are distinguished by high physico-chemical variability, yet we know little about how these symbioses respond to environmental fluctuations. We therefore examined how the γ-proteobacterial symbionts of the vent snail Ifremeria nautilei respond to changes in sulfur geochemistry. Via shipboard high-pressure incubations, we subjected snails to 105 μM hydrogen sulfide (LS), 350 μM hydrogen sulfide (HS), 300 μM thiosulfate (TS) and seawater without any added inorganic electron donor (ND). While transcript levels of sulfur oxidation genes were largely consistent across treatments, HS and TS treatments stimulated genes for denitrification, nitrogen assimilation, and CO2 fixation, coincident with previously reported enhanced rates of inorganic carbon incorporation and sulfur oxidation in these treatments. Transcripts for genes mediating oxidative damage were enriched in the ND and LS treatments, potentially due to a reduction in O2 scavenging when electron donors were scarce. Oxidative TCA cycle gene transcripts were also more abundant in ND and LS treatments, suggesting that I. nautilei symbionts may be mixotrophic when inorganic electron donors are limiting. These data reveal the extent to which I. nautilei symbionts respond to changes in sulfur concentration and species, and, interpreted alongside coupled biochemical metabolic rates, identify gene targets whose expression patterns may be predictive of holobiont physiology in environmental samples.}, }
@article {pmid27485233, year = {2016}, author = {Mansour, TA and Rosenthal, JJ and Brown, CT and Roberson, LM}, title = {Transcriptome of the Caribbean stony coral Porites astreoides from three developmental stages.}, journal = {GigaScience}, volume = {5}, number = {1}, pages = {33}, doi = {10.1186/s13742-016-0138-1}, pmid = {27485233}, issn = {2047-217X}, support = {P20 GM103475/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Anthozoa/genetics/*growth &amp; development/parasitology ; Caribbean Region ; Coral Reefs ; Dinoflagellida/*genetics/physiology ; Gene Expression Profiling/*methods ; Gene Expression Regulation, Developmental ; Gene Library ; Sequence Analysis, RNA/*methods ; Symbiosis ; }, abstract = {BACKGROUND: Porites astreoides is a ubiquitous species of coral on modern Caribbean reefs that is resistant to increasing temperatures, overfishing, and other anthropogenic impacts that have threatened most other coral species. We assembled and annotated a transcriptome from this coral using Illumina sequences from three different developmental stages collected over several years: free-swimming larvae, newly settled larvae, and adults (>10 cm in diameter). This resource will aid understanding of coral calcification, larval settlement, and host-symbiont interactions.<br><br>FINDINGS: A de novo transcriptome for the P. astreoides holobiont (coral plus algal symbiont) was assembled using 594 Mbp of raw Illumina sequencing data generated from five age-specific cDNA libraries. The new transcriptome consists of 867 255 transcript elements with an average length of 685 bases. The isolated P. astreoides assembly consists of 129 718 transcript elements with an average length of 811 bases, and the isolated Symbiodinium sp. assembly had 186 177 transcript elements with an average length of 1105 bases.<br><br>CONCLUSIONS: This contribution to coral transcriptome data provides a valuable resource for researchers studying the ontogeny of gene expression patterns within both the coral and its dinoflagellate symbiont.}, }
@article {pmid27482741, year = {2016}, author = {Bourne, DG and Morrow, KM and Webster, NS}, title = {Insights into the Coral Microbiome: Underpinning the Health and Resilience of Reef Ecosystems.}, journal = {Annual review of microbiology}, volume = {70}, number = {}, pages = {317-340}, doi = {10.1146/annurev-micro-102215-095440}, pmid = {27482741}, issn = {1545-3251}, mesh = {Animals ; Anthozoa/genetics/*microbiology/*physiology ; Bacteria/classification/genetics/growth &amp; development/*isolation &amp; purification ; Coral Reefs ; Ecosystem ; Fungi/classification/genetics/growth &amp; development/*isolation &amp; purification ; *Microbiota ; }, abstract = {Corals are fundamental ecosystem engineers, creating large, intricate reefs that support diverse and abundant marine life. At the core of a healthy coral animal is a dynamic relationship with microorganisms, including a mutually beneficial symbiosis with photosynthetic dinoflagellates (Symbiodinium spp.) and enduring partnerships with an array of bacterial, archaeal, fungal, protistan, and viral associates, collectively termed the coral holobiont. The combined genomes of this coral holobiont form a coral hologenome, and genomic interactions within the hologenome ultimately define the coral phenotype. Here we integrate contemporary scientific knowledge regarding the ecological, host-specific, and environmental forces shaping the diversity, specificity, and distribution of microbial symbionts within the coral holobiont, explore physiological pathways that contribute to holobiont fitness, and describe potential mechanisms for holobiont homeostasis. Understanding the role of the microbiome in coral resilience, acclimation, and environmental adaptation is a new frontier in reef science that will require large-scale collaborative research efforts.}, }
@article {pmid27468993, year = {2017}, author = {Bandyopadhyay, P and Bhuyan, SK and Yadava, PK and Varma, A and Tuteja, N}, title = {Emergence of plant and rhizospheric microbiota as stable interactomes.}, journal = {Protoplasma}, volume = {254}, number = {2}, pages = {617-626}, doi = {10.1007/s00709-016-1003-x}, pmid = {27468993}, issn = {1615-6102}, mesh = {Ecosystem ; *Microbial Interactions ; *Microbiota ; Models, Biological ; Plants/*microbiology ; *Rhizosphere ; }, abstract = {The growing human population and depletion of resources have necessitated development of sustainable agriculture. Beneficial plant-microbe associations have been known for quite some time now. To maintain sustainability, one could show better reliance upon beneficial attributes of the rhizosphere microbiome. To harness the best agronomic traits, understanding the entire process of recruitment, establishment, and maintenance of microbiota as stable interactome within the rhizosphere is important. In this article, we highlight the process of recruitment and establishment of microbiota within rhizosphere. Further, we have discussed the interlinkages and the ability of multiple (microbial and plant) partners to interact with one another forming a stable plant holobiont system. Lastly, we address the possibility of exploring the knowledge gained from the holobiont system to tailor the rhizosphere microbiome for better productivity and maintenance of agroecosystems. The article provide new insights into the broad principles of stable plant-microbe interactions which could be useful for sustaining agriculture and food security.}, }
@article {pmid27446031, year = {2016}, author = {Egan, S and Gardiner, M}, title = {Microbial Dysbiosis: Rethinking Disease in Marine Ecosystems.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {991}, doi = {10.3389/fmicb.2016.00991}, pmid = {27446031}, issn = {1664-302X}, abstract = {With growing environmental pressures placed on our marine habitats there is concern that the prevalence and severity of diseases affecting marine organisms will increase. Yet relative to terrestrial systems, we know little about the underlying causes of many of these diseases. Moreover, factors such as saprophytic colonizers and a lack of baseline data on healthy individuals make it difficult to accurately assess the role of specific microbial pathogens in disease states. Emerging evidence in the field of medicine suggests that a growing number of human diseases result from a microbiome imbalance (or dysbiosis), questioning the traditional view of a singular pathogenic agent. Here we discuss the possibility that many diseases seen in marine systems are, similarly, the result of microbial dysbiosis and the rise of opportunistic or polymicrobial infections. Thus, understanding and managing disease in the future will require us to also rethink definitions of disease and pathogenesis for marine systems. We suggest that a targeted, multidisciplinary approach that addresses the questions of microbial symbiosis in both healthy and diseased states, and at that the level of the holobiont, will be key to progress in this area.}, }
@article {pmid27418200, year = {2016}, author = {Mitter, B and Pfaffenbichler, N and Sessitsch, A}, title = {Plant-microbe partnerships in 2020.}, journal = {Microbial biotechnology}, volume = {9}, number = {5}, pages = {635-640}, doi = {10.1111/1751-7915.12382}, pmid = {27418200}, issn = {1751-7915}, mesh = {Agriculture/*methods/trends ; *Ecosystem ; Plants/*microbiology ; }, abstract = {The plant holobiont comprises the plant and its associated microbiota, which interact with each other and determine holobiont functioning and plant performance. We have started to understand the complexity of the involved microorganisms and their interactions, however, we need more research on plant-microbiome interactions to understand holobiont functioning. By 2020 we expect that our knowledge on these interactions will have considerably increased facilitating crop management practices based on the interactions of the plant holobiont.}, }
@article {pmid27392086, year = {2017}, author = {Neave, MJ and Rachmawati, R and Xun, L and Michell, CT and Bourne, DG and Apprill, A and Voolstra, CR}, title = {Differential specificity between closely related corals and abundant Endozoicomonas endosymbionts across global scales.}, journal = {The ISME journal}, volume = {11}, number = {1}, pages = {186-200}, doi = {10.1038/ismej.2016.95}, pmid = {27392086}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/classification/*microbiology ; Coral Reefs ; Gammaproteobacteria/classification/genetics/isolation &amp; purification/*physiology ; Genotype ; In Situ Hybridization, Fluorescence ; *Symbiosis ; }, abstract = {Reef-building corals are well regarded not only for their obligate association with endosymbiotic algae, but also with prokaryotic symbionts, the specificity of which remains elusive. To identify the central microbial symbionts of corals, their specificity across species and conservation over geographic regions, we sequenced partial SSU ribosomal RNA genes of Bacteria and Archaea from the common corals Stylophora pistillata and Pocillopora verrucosa across 28 reefs within seven major geographical regions. We demonstrate that both corals harbor Endozoicomonas bacteria as their prevalent symbiont. Importantly, catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH) with Endozoicomonas-specific probes confirmed their residence as large aggregations deep within coral tissues. Using fine-scale genotyping techniques and single-cell genomics, we demonstrate that P. verrucosa harbors the same Endozoicomonas, whereas S. pistillata associates with geographically distinct genotypes. This specificity may be shaped by the different reproductive strategies of the hosts, potentially uncovering a pattern of symbiont selection that is linked to life history. Spawning corals such as P. verrucosa acquire prokaryotes from the environment. In contrast, brooding corals such as S. pistillata release symbiont-packed planula larvae, which may explain a strong regional signature in their microbiome. Our work contributes to the factors underlying microbiome specificity and adds detail to coral holobiont functioning.}, }
@article {pmid27375564, year = {2016}, author = {Laffy, PW and Wood-Charlson, EM and Turaev, D and Weynberg, KD and Botté, ES and van Oppen, MJ and Webster, NS and Rattei, T}, title = {HoloVir: A Workflow for Investigating the Diversity and Function of Viruses in Invertebrate Holobionts.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {822}, doi = {10.3389/fmicb.2016.00822}, pmid = {27375564}, issn = {1664-302X}, abstract = {Abundant bioinformatics resources are available for the study of complex microbial metagenomes, however their utility in viral metagenomics is limited. HoloVir is a robust and flexible data analysis pipeline that provides an optimized and validated workflow for taxonomic and functional characterization of viral metagenomes derived from invertebrate holobionts. Simulated viral metagenomes comprising varying levels of viral diversity and abundance were used to determine the optimal assembly and gene prediction strategy, and multiple sequence assembly methods and gene prediction tools were tested in order to optimize our analysis workflow. HoloVir performs pairwise comparisons of single read and predicted gene datasets against the viral RefSeq database to assign taxonomy and additional comparison to phage-specific and cellular markers is undertaken to support the taxonomic assignments and identify potential cellular contamination. Broad functional classification of the predicted genes is provided by assignment of COG microbial functional category classifications using EggNOG and higher resolution functional analysis is achieved by searching for enrichment of specific Swiss-Prot keywords within the viral metagenome. Application of HoloVir to viral metagenomes from the coral Pocillopora damicornis and the sponge Rhopaloeides odorabile demonstrated that HoloVir provides a valuable tool to characterize holobiont viral communities across species, environments, or experiments.}, }
@article {pmid27264698, year = {2016}, author = {Ribes, M and Calvo, E and Movilla, J and Logares, R and Coma, R and Pelejero, C}, title = {Restructuring of the sponge microbiome favors tolerance to ocean acidification.}, journal = {Environmental microbiology reports}, volume = {8}, number = {4}, pages = {536-544}, doi = {10.1111/1758-2229.12430}, pmid = {27264698}, issn = {1758-2229}, mesh = {Adaptation, Physiological ; Animals ; Hydrogen-Ion Concentration ; *Microbiota ; Oceans and Seas ; Porifera/drug effects/*microbiology/*physiology ; Seawater/*chemistry ; Survival Analysis ; }, abstract = {Ocean acidification is increasing and affects many marine organisms. However, certain sponge species can withstand low-pH conditions. This may be related to their complex association with microbes. We hypothesized that species with greater microbial diversity may develop functional redundancy that could enable the holobiont to survive even if particular microbes are lost at low-pH conditions. We evaluated the effects of acidification on the growth and associated microbes of three ubiquitous Mediterranean sponges by exposing them to the present pH level and that predicted for the year 2100. We found marked differences among the species in the acquisition of new microbes, being high in Dysidea avara, moderate in Agelas oroides and null in Chondrosia reniformis; however, we did not observe variation in the overall microbiome abundance, richness or diversity. The relative abilities to alter the microbiomes contributes to survivorship in an OA scenario as demonstrated by lowered pH severely affecting the growth of C. reniformis, halving that of A. oroides, and unaffecting D. avara. Our results indicate that functional stability of the sponge holobiont to withstand future OA is species-specific and is linked to the species' ability to use horizontal transmission to modify the associated microbiome to adapt to environmental change.}, }
@article {pmid27234003, year = {2016}, author = {Cardini, U and van Hoytema, N and Bednarz, VN and Rix, L and Foster, RA and Al-Rshaidat, MM and Wild, C}, title = {Microbial dinitrogen fixation in coral holobionts exposed to thermal stress and bleaching.}, journal = {Environmental microbiology}, volume = {18}, number = {8}, pages = {2620-2633}, doi = {10.1111/1462-2920.13385}, pmid = {27234003}, issn = {1462-2920}, mesh = {Animals ; *Anthozoa/metabolism/microbiology/parasitology ; Bacteria/growth &amp; development/*metabolism ; Dinoflagellida/growth &amp; development/*metabolism ; Global Warming ; Heterotrophic Processes ; Hot Temperature ; Microbiota/physiology ; Nitrogen Fixation/*physiology ; Photosynthesis/physiology ; Stress, Physiological/physiology ; Symbiosis/physiology ; }, abstract = {Coral holobionts (i.e., coral-algal-prokaryote symbioses) exhibit dissimilar thermal sensitivities that may determine which coral species will adapt to global warming. Nonetheless, studies simultaneously investigating the effects of warming on all holobiont members are lacking. Here we show that exposure to increased temperature affects key physiological traits of all members (herein: animal host, zooxanthellae and diazotrophs) of both Stylophora pistillata and Acropora hemprichii during and after thermal stress. S. pistillata experienced severe loss of zooxanthellae (i.e., bleaching) with no net photosynthesis at the end of the experiment. Conversely, A. hemprichii was more resilient to thermal stress. Exposure to increased temperature (+ 6°C) resulted in a drastic increase in daylight dinitrogen (N2) fixation, particularly in A. hemprichii (threefold compared with controls). After the temperature was reduced again to in situ levels, diazotrophs exhibited a reversed diel pattern of activity, with increased N2 fixation rates recorded only in the dark, particularly in bleached S. pistillata (twofold compared to controls). Concurrently, both animal hosts, but particularly bleached S. pistillata, reduced both organic matter release and heterotrophic feeding on picoplankton. Our findings indicate that physiological plasticity by coral-associated diazotrophs may play an important role in determining the response of coral holobionts to ocean warming.}, }
@article {pmid27230747, year = {2016}, author = {Maistrenko, OM and Serga, SV and Vaiserman, AM and Kozeretska, IA}, title = {Longevity-modulating effects of symbiosis: insights from Drosophila-Wolbachia interaction.}, journal = {Biogerontology}, volume = {17}, number = {5-6}, pages = {785-803}, doi = {10.1007/s10522-016-9653-9}, pmid = {27230747}, issn = {1573-6768}, mesh = {Aging/*physiology ; Animals ; Bacterial Proteins/metabolism ; Drosophila/*microbiology/*physiology ; Drosophila Proteins/metabolism ; Longevity/*physiology ; Models, Biological ; Symbiosis/*physiology ; Wolbachia/*physiology ; }, abstract = {Microbial communities are known to significantly affect various fitness components and survival of their insect hosts, including Drosophila. The composition of symbiotic microbiota has been shown to change with the host's aging. It is unclear whether these changes are caused by the aging process or, vice versa, they affect the host's aging and longevity. Recent findings indicate that fitness and lifespan of Drosophila are affected by endosymbiotic bacteria Wolbachia. These effects, however, are inconsistent and have been reported both to extend and shorten longevity. The main molecular pathways underlying the lifespan-modulating effects of Wolbachia remain unclear, however insulin/insulin-like growth factor, immune deficiency, ecdysteroid synthesis and signaling and c-Jun N-terminal kinase pathways as well as heat shock protein synthesis and autophagy have been proposed to play a role. Here we revise the current evidence that elucidates the impact of Wolbachia endosymbionts on the aging processes in Drosophila.}, }
@article {pmid27213462, year = {2016}, author = {Miller, WB}, title = {Cognition, Information Fields and Hologenomic Entanglement: Evolution in Light and Shadow.}, journal = {Biology}, volume = {5}, number = {2}, pages = {}, doi = {10.3390/biology5020021}, pmid = {27213462}, issn = {2079-7737}, abstract = {As the prime unification of Darwinism and genetics, the Modern Synthesis continues to epitomize mainstay evolutionary theory. Many decades after its formulation, its anchor assumptions remain fixed: conflict between macro organic organisms and selection at that level represent the near totality of any evolutionary narrative. However, intervening research has revealed a less easily appraised cellular and microbial focus for eukaryotic existence. It is now established that all multicellular eukaryotic organisms are holobionts representing complex collaborations between the co-aligned microbiome of each eukaryote and its innate cells into extensive mixed cellular ecologies. Each of these ecological constituents has demonstrated faculties consistent with basal cognition. Consequently, an alternative hologenomic entanglement model is proposed with cognition at its center and conceptualized as Pervasive Information Fields within a quantum framework. Evolutionary development can then be reconsidered as being continuously based upon communication between self-referential constituencies reiterated at every scope and scale. Immunological reactions support and reinforce self-recognition juxtaposed against external environmental stresses.}, }
@article {pmid27160191, year = {2016}, author = {Dirksen, P and Marsh, SA and Braker, I and Heitland, N and Wagner, S and Nakad, R and Mader, S and Petersen, C and Kowallik, V and Rosenstiel, P and Félix, MA and Schulenburg, H}, title = {The native microbiome of the nematode Caenorhabditis elegans: gateway to a new host-microbiome model.}, journal = {BMC biology}, volume = {14}, number = {}, pages = {38}, doi = {10.1186/s12915-016-0258-1}, pmid = {27160191}, issn = {1741-7007}, mesh = {Animals ; Antifungal Agents/metabolism ; Caenorhabditis elegans/growth &amp; development/*microbiology ; Life Cycle Stages ; *Microbiota ; *Models, Biological ; Phenotype ; Proteobacteria/isolation &amp; purification/metabolism ; Species Specificity ; }, abstract = {BACKGROUND: Host-microbe associations underlie many key processes of host development, immunity, and life history. Yet, none of the current research on the central model species Caenorhabditis elegans considers the worm's natural microbiome. Instead, almost all laboratories exclusively use the canonical strain N2 and derived mutants, maintained through routine bleach sterilization in monoxenic cultures with an E. coli strain as food. Here, we characterize for the first time the native microbiome of C. elegans and assess its influence on nematode life history characteristics.<br><br>RESULTS: Nematodes sampled directly from their native habitats carry a species-rich bacterial community, dominated by Proteobacteria such as Enterobacteriaceae and members of the genera Pseudomonas, Stenotrophomonas, Ochrobactrum, and Sphingomonas. The C. elegans microbiome is distinct from that of the worm's natural environment and the congeneric species C. remanei. Exposure to a derived experimental microbiome revealed that bacterial composition is influenced by host developmental stage and genotype. These experiments also showed that the microbes enhance host fitness under standard and also stressful conditions (e.g., high temperature and either low or high osmolarity). Taking advantage of the nematode's transparency, we further demonstrate that several Proteobacteria are able to enter the C. elegans gut and that an Ochrobactrum isolate even seems to be able to persist in the intestines under stressful conditions. Moreover, three Pseudomonas isolates produce an anti-fungal effect in vitro which we show can contribute to the worm's defense against fungal pathogens in vivo.<br><br>CONCLUSION: This first systematic analysis of the nematode's native microbiome reveals a species-rich bacterial community to be associated with C. elegans, which is likely of central importance for our understanding of the worm's biology. The information acquired and the microbial isolates now available for experimental work establishes C. elegans as a tractable model for the in-depth dissection of host-microbiome interactions.}, }
@article {pmid27148918, year = {2016}, author = {Rosenberg, E and Zilber-Rosenberg, I}, title = {Do microbiotas warm their hosts?.}, journal = {Gut microbes}, volume = {7}, number = {4}, pages = {283-285}, doi = {10.1080/19490976.2016.1182294}, pmid = {27148918}, issn = {1949-0984}, mesh = {Animals ; Bacteria/genetics/isolation &amp; purification/*metabolism ; Energy Metabolism ; Gastrointestinal Tract/metabolism/*microbiology ; Hot Temperature ; Humans ; Insecta/microbiology ; *Microbiota ; Plants/microbiology ; }, abstract = {All natural animals and plants are holobionts, consisting of a host and abundant and diverse microbiota. During the last 20 years, numerous studies have shown that microbiotas participate in the ability of their hosts to survive and reproduce in a particular environment in many ways, including contributing to their morphology, development, behavior, physiology, resistance to disease and to their evolution. Here we posit another possible contribution of microbiotas to their hosts, which has been underexplored - the generation of heat. We estimate that microbial metabolism in the human gut, for example, produces 61 kcal/h, which corresponds to approximately 70% of the total heat production of an average person at rest.}, }
@article {pmid27148239, year = {2016}, author = {Aires, T and Serrão, EA and Engelen, AH}, title = {Host and Environmental Specificity in Bacterial Communities Associated to Two Highly Invasive Marine Species (Genus Asparagopsis).}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {559}, doi = {10.3389/fmicb.2016.00559}, pmid = {27148239}, issn = {1664-302X}, abstract = {As habitats change due to global and local pressures, population resilience, and adaptive processes depend not only on their gene pools but also on their associated bacteria communities. The hologenome can play a determinant role in adaptive evolution of higher organisms that rely on their bacterial associates for vital processes. In this study, we focus on the associated bacteria of the two most invasive seaweeds in southwest Iberia (coastal mainland) and nearby offshore Atlantic islands, Asparagopsis taxiformis and Asparagopsis armata. Bacterial communities were characterized using 16S rRNA barcoding through 454 next generation sequencing and exploratory shotgun metagenomics to provide functional insights and a backbone for future functional studies. The bacterial community composition was clearly different between the two species A. taxiformis and A. armata and between continental and island habitats. The latter was mainly due to higher abundances of Acidimicrobiales, Sphingomonadales, Xanthomonadales, Myxococcales, and Alteromonadales on the continent. Metabolic assignments for these groups contained a higher number of reads in functions related to oxidative stress and resistance to toxic compounds, more precisely heavy metals. These results are in agreement with their usual association with hydrocarbon degradation and heavy-metals detoxification. In contrast, A. taxiformis from islands contained more bacteria related to oligotrophic environments which might putatively play a role in mineralization of dissolved organic matter. The higher number of functional assignments found in the metagenomes of A. taxiformis collected from Cape Verde Islands suggest a higher contribution of bacteria to compensate nutrient limitation in oligotrophic environments. Our results show that Asparagopsis-associated bacterial communities have host-specificity and are modulated by environmental conditions. Whether this environmental effect reflects the host's selective requirements or the locally available bacteria remains to be addressed. However, the known functional capacities of these bacterial communities indicate their potential for eco-physiological functions that could be valuable for the host fitness.}, }
@article {pmid27148067, year = {2016}, author = {Hawkins, TD and Hagemeyer, JC and Hoadley, KD and Marsh, AG and Warner, ME}, title = {Partitioning of Respiration in an Animal-Algal Symbiosis: Implications for Different Aerobic Capacity between Symbiodinium spp.}, journal = {Frontiers in physiology}, volume = {7}, number = {}, pages = {128}, doi = {10.3389/fphys.2016.00128}, pmid = {27148067}, issn = {1664-042X}, abstract = {Cnidarian-dinoflagellate symbioses are ecologically important and the subject of much investigation. However, our understanding of critical aspects of symbiosis physiology, such as the partitioning of total respiration between the host and symbiont, remains incomplete. Specifically, we know little about how the relationship between host and symbiont respiration varies between different holobionts (host-symbiont combinations). We applied molecular and biochemical techniques to investigate aerobic respiratory capacity in naturally symbiotic Exaiptasia pallida sea anemones, alongside animals infected with either homologous ITS2-type A4 Symbiodinium or a heterologous isolate of Symbiodinium minutum (ITS2-type B1). In naturally symbiotic anemones, host, symbiont, and total holobiont mitochondrial citrate synthase (CS) enzyme activity, but not host mitochondrial copy number, were reliable predictors of holobiont respiration. There was a positive association between symbiont density and host CS specific activity (mg protein(-1)), and a negative correlation between host- and symbiont CS specific activities. Notably, partitioning of total CS activity between host and symbiont in this natural E. pallida population was significantly different to the host/symbiont biomass ratio. In re-infected anemones, we found significant between-holobiont differences in the CS specific activity of the algal symbionts. Furthermore, the relationship between the partitioning of total CS activity and the host/symbiont biomass ratio differed between holobionts. These data have broad implications for our understanding of cnidarian-algal symbiosis. Specifically, the long-held assumption of equivalency between symbiont/host biomass and respiration ratios can result in significant overestimation of symbiont respiration and potentially erroneous conclusions regarding the percentage of carbon translocated to the host. The interspecific variability in symbiont aerobic capacity provides further evidence for distinct physiological differences that should be accounted for when studying diverse host-symbiont combinations.}, }
@article {pmid27103626, year = {2016}, author = {Webster, NS and Thomas, T}, title = {The Sponge Hologenome.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e00135-16}, doi = {10.1128/mBio.00135-16}, pmid = {27103626}, issn = {2150-7511}, mesh = {Animals ; Bacteria/classification/*genetics/*isolation &amp; purification ; Bacterial Physiological Phenomena ; *Genome, Bacterial ; Microbial Consortia ; Porifera/*microbiology/physiology ; Symbiosis ; }, abstract = {A paradigm shift has recently transformed the field of biological science; molecular advances have revealed how fundamentally important microorganisms are to many aspects of a host's phenotype and evolution. In the process, an era of &quot;holobiont&quot; research has emerged to investigate the intricate network of interactions between a host and its symbiotic microbial consortia. Marine sponges are early-diverging metazoa known for hosting dense, specific, and often highly diverse microbial communities. Here we synthesize current thoughts about the environmental and evolutionary forces that influence the diversity, specificity, and distribution of microbial symbionts within the sponge holobiont, explore the physiological pathways that contribute to holobiont function, and describe the molecular mechanisms that underpin the establishment and maintenance of these symbiotic partnerships. The collective genomes of the sponge holobiont form the sponge hologenome, and we highlight how the forces that define a sponge's phenotype in fact act on the genomic interplay between the different components of the holobiont.}, }
@article {pmid27092120, year = {2016}, author = {Lawler, SN and Kellogg, CA and France, SC and Clostio, RW and Brooke, SD and Ross, SW}, title = {Coral-Associated Bacterial Diversity Is Conserved across Two Deep-Sea Anthothela Species.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {458}, doi = {10.3389/fmicb.2016.00458}, pmid = {27092120}, issn = {1664-302X}, abstract = {Cold-water corals, similar to tropical corals, contain diverse and complex microbial assemblages. These bacteria provide essential biological functions within coral holobionts, facilitating increased nutrient utilization and production of antimicrobial compounds. To date, few cold-water octocoral species have been analyzed to explore the diversity and abundance of their microbial associates. For this study, 23 samples of the family Anthothelidae were collected from Norfolk (n = 12) and Baltimore Canyons (n = 11) from the western Atlantic in August 2012 and May 2013. Genetic testing found that these samples comprised two Anthothela species (Anthothela grandiflora and Anthothela sp.) and Alcyonium grandiflorum. DNA was extracted and sequenced with primers targeting the V4-V5 variable region of the 16S rRNA gene using 454 pyrosequencing with GS FLX Titanium chemistry. Results demonstrated that the coral host was the primary driver of bacterial community composition. Al. grandiflorum, dominated by Alteromonadales and Pirellulales had much higher species richness, and a distinct bacterial community compared to Anthothela samples. Anthothela species (A. grandiflora and Anthothela sp.) had very similar bacterial communities, dominated by Oceanospirillales and Spirochaetes. Additional analysis of core-conserved bacteria at 90% sample coverage revealed genus level conservation across Anthothela samples. This core included unclassified Oceanospirillales, Kiloniellales, Campylobacterales, and genus Spirochaeta. Members of this core were previously recognized for their functional capabilities in nitrogen cycling and suggest the possibility of a nearly complete nitrogen cycle within Anthothela species. Overall, many of the bacterial associates identified in this study have the potential to contribute to the acquisition and cycling of nutrients within the coral holobiont.}, }
@article {pmid27084955, year = {2016}, author = {Collier, RJ and Casadevall, A}, title = {The Holobiont/Hologenome Concept Series.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e00605-16}, doi = {10.1128/mBio.00605-16}, pmid = {27084955}, issn = {2150-7511}, mesh = {Editorial Policies ; *Genome ; Humans ; *Symbiosis ; }, }
@article {pmid27047481, year = {2016}, author = {Lee, ST and Davy, SK and Tang, SL and Kench, PS}, title = {Mucus Sugar Content Shapes the Bacterial Community Structure in Thermally Stressed Acropora muricata.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {371}, doi = {10.3389/fmicb.2016.00371}, pmid = {27047481}, issn = {1664-302X}, abstract = {It has been proposed that the chemical composition of a coral's mucus can influence the associated bacterial community. However, information on this topic is rare, and non-existent for corals that are under thermal stress. This study therefore compared the carbohydrate composition of mucus in the coral Acropora muricata when subjected to increasing thermal stress from 26 to 31°C, and determined whether this composition correlated with any changes in the bacterial community. Results showed that, at lower temperatures, the main components of mucus were N-acetyl glucosamine and C6 sugars, but these constituted a significantly lower proportion of the mucus in thermally stressed corals. The change in the mucus composition coincided with a shift from a γ-Proteobacteria- to a Verrucomicrobiae- and α-Proteobacteria-dominated community in the coral mucus. Bacteria in the class Cyanobacteria also started to become prominent in the mucus when the coral was thermally stressed. The increase in the relative abundance of the Verrucomicrobiae at higher temperature was strongly associated with a change in the proportion of fucose, glucose, and mannose in the mucus. Increase in the relative abundance of α-Proteobacteria were associated with GalNAc and glucose, while the drop in relative abundance of γ-Proteobacteria at high temperature coincided with changes in fucose and mannose. Cyanobacteria were highly associated with arabinose and xylose. Changes in mucus composition and the bacterial community in the mucus layer occurred at 29°C, which were prior to visual signs of coral bleaching at 31°C. A compositional change in the coral mucus, induced by thermal stress could therefore be a key factor leading to a shift in the associated bacterial community. This, in turn, has the potential to impact the physiological function of the coral holobiont.}, }
@article {pmid27039196, year = {2016}, author = {Shapira, M}, title = {Gut Microbiotas and Host Evolution: Scaling Up Symbiosis.}, journal = {Trends in ecology &amp; evolution}, volume = {31}, number = {7}, pages = {539-549}, doi = {10.1016/j.tree.2016.03.006}, pmid = {27039196}, issn = {1872-8383}, mesh = {Animals ; *Biological Evolution ; *Gastrointestinal Microbiome ; Genome, Bacterial ; Microbiota ; *Symbiosis ; }, abstract = {Our understanding of species evolution is undergoing restructuring. It is well accepted that host-symbiont coevolution is responsible for fundamental aspects of biology. However, the emerging importance of plant- and animal-associated microbiotas to their hosts suggests a scale of coevolutionary interactions many-fold greater than previously considered. This review builds on current understanding of symbionts and their contributions to host evolution to evaluate recent data demonstrating similar contributions of gut microbiotas. It further considers a multilayered model for microbiota to account for emerging themes in host-microbiota interactions. Drawing on the structure of bacterial genomes, this model distinguishes between a host-adapted core microbiota, and a flexible, environmentally modulated microbial pool, differing in constraints on their maintenance and in their contributions to host adaptation.}, }
@article {pmid27036743, year = {2015}, author = {Berlanga, M}, title = {Functional symbiosis and communication in microbial ecosystems. The case of wood-eating termites and cockroaches.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {18}, number = {3}, pages = {159-169}, doi = {10.2436/20.1501.01.246}, pmid = {27036743}, issn = {1139-6709}, mesh = {Animals ; Bacteria/classification/genetics/isolation &amp; purification/*metabolism ; Biodiversity ; Cockroaches/metabolism/*microbiology ; Gastrointestinal Tract/microbiology ; Humans ; Isoptera/metabolism/*microbiology ; Phylogeny ; Symbiosis ; Wood/metabolism/microbiology ; }, abstract = {Animal hosts typically have strong specificity for microbial symbionts and their functions. The symbiotic relationships have enhanced the limited metabolic networks of most eukaryotes by contributing several prokaryotic metabolic capabilities, such as methanogenesis, chemolithoautotrophy, nitrogen assimilation, etc. This review will examine the characteristics that determine bacterial &quot;fidelity&quot; to certain groups of animals (e.g., xylophagous insects, such as termites and cockroaches) over generations and throughout evolution. The hindgut bacteria of wood-feeding termites and cockroaches belong to several phyla, including Proteobacteria, especially Deltaproteobacteria, Bacteroidetes, Firmicutes, Actinomycetes, Spirochetes, Verrucomicrobia, and Actinobacteria, as detected by 16S rRNA. Termites effectively feed on many types of lignocelluloses assisted by their gut microbial symbionts. Although the community structures differ between the hosts (termites and cockroaches), with changes in the relative abundances of particular bacterial taxa, the composition of the bacterial community could reflect at least in part the host evolution in that the microbiota may derive from the microbiota of a common ancestor. Therefore, factors other than host phylogeny, such as diet could have had strong influence in shaping the bacterial community structure.}, }
@article {pmid27034285, year = {2016}, author = {Douglas, AE and Werren, JH}, title = {Holes in the Hologenome: Why Host-Microbe Symbioses Are Not Holobionts.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e02099}, doi = {10.1128/mBio.02099-15}, pmid = {27034285}, issn = {2150-7511}, mesh = {Animals ; Biological Evolution ; *Biota ; Humans ; *Microbiota ; Plants ; *Symbiosis ; }, abstract = {The advent of relatively inexpensive tools for characterizing microbial communities has led to an explosion of research exploring the diversity, ecology, and evolution of microbe-host systems. Some now question whether existing conceptual frameworks are adequate to explain microbe-host systems. One popular paradigm is the &quot;holobiont-hologenome,&quot; which argues that a host and its microbiome evolve as a single cooperative unit of selection (i.e., a superorganism). We argue that the hologenome is based on overly restrictive assumptions which render it an approach of little research utility. A host plus its microbiome is more effectively viewed as an ecological community of organisms that encompasses a broad range of interactions (parasitic to mutualistic), patterns of transmission (horizontal to vertical), and levels of fidelity among partners. The hologenome requires high partner fidelity if it is to evolve as a unit. However, even when this is achieved by particular host-microbe pairs, it is unlikely to hold for the entire host microbiome, and therefore the community is unlikely to evolve as a hologenome. Both mutualistic and antagonistic (fitness conflict) evolution can occur among constituent members of the community, not just adaptations at the &quot;hologenome&quot; level, and there is abundant empirical evidence for such divergence of selective interests among members of host-microbiome communities. We believe that the concepts and methods of ecology, genetics, and evolutionary biology will continue to provide a well-grounded intellectual framework for researching host-microbiome communities, without recourse to the limiting assumption that selection acts predominantly at the holobiont level.}, }
@article {pmid27034284, year = {2016}, author = {Shropshire, JD and Bordenstein, SR}, title = {Speciation by Symbiosis: the Microbiome and Behavior.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e01785}, doi = {10.1128/mBio.01785-15}, pmid = {27034284}, issn = {2150-7511}, mesh = {Animals ; Behavior ; Behavior, Animal ; *Genetic Speciation ; Humans ; *Microbiota ; *Symbiosis ; }, abstract = {Species are fundamental units of comparison in biology. The newly discovered importance and ubiquity of host-associated microorganisms are now stimulating work on the roles that microbes can play in animal speciation. We previously synthesized the literature and advanced concepts of speciation by symbiosis with notable attention to hybrid sterility and lethality. Here, we review recent studies and relevant data on microbes as players in host behavior and behavioral isolation, emphasizing the patterns seen in these analyses and highlighting areas worthy of additional exploration. We conclude that the role of microbial symbionts in behavior and speciation is gaining exciting traction and that the holobiont and hologenome concepts afford an evolving intellectual framework to promote research and intellectual exchange between disciplines such as behavior, microbiology, genetics, symbiosis, and speciation. Given the increasing centrality of microbiology in macroscopic life, microbial symbiosis is arguably the most neglected aspect of animal and plant speciation, and studying it should yield a better understanding of the origin of species.}, }
@article {pmid27034283, year = {2016}, author = {Rosenberg, E and Zilber-Rosenberg, I}, title = {Microbes Drive Evolution of Animals and Plants: the Hologenome Concept.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e01395}, doi = {10.1128/mBio.01395-15}, pmid = {27034283}, issn = {2150-7511}, mesh = {Adaptation, Biological ; Animals ; *Biological Evolution ; *Biota ; Humans ; *Microbiota ; Plants ; Recombination, Genetic ; Selection, Genetic ; *Symbiosis ; }, abstract = {The hologenome concept of evolution postulates that the holobiont (host plus symbionts) with its hologenome (host genome plus microbiome) is a level of selection in evolution. Multicellular organisms can no longer be considered individuals by the classical definitions of the term. Every natural animal and plant is a holobiont consisting of the host and diverse symbiotic microbes and viruses. Microbial symbionts can be transmitted from parent to offspring by a variety of methods, including via cytoplasmic inheritance, coprophagy, direct contact during and after birth, and the environment. A large number of studies have demonstrated that these symbionts contribute to the anatomy, physiology, development, innate and adaptive immunity, and behavior and finally also to genetic variation and to the origin and evolution of species. Acquisition of microbes and microbial genes is a powerful mechanism for driving the evolution of complexity. Evolution proceeds both via cooperation and competition, working in parallel.}, }
@article {pmid27034282, year = {2016}, author = {McFall-Ngai, M}, title = {Introduction to the Hologenome Special Series.}, journal = {mBio}, volume = {7}, number = {2}, pages = {e00371}, doi = {10.1128/mBio.00371-16}, pmid = {27034282}, issn = {2150-7511}, mesh = {Adaptation, Biological ; Animals ; *Biological Evolution ; *Biota ; Humans ; *Microbiota ; Plants ; Selection, Genetic ; *Symbiosis ; }, }
@article {pmid27019410, year = {2016}, author = {Haichar, FEZ and Heulin, T and Guyonnet, JP and Achouak, W}, title = {Stable isotope probing of carbon flow in the plant holobiont.}, journal = {Current opinion in biotechnology}, volume = {41}, number = {}, pages = {9-13}, doi = {10.1016/j.copbio.2016.02.023}, pmid = {27019410}, issn = {1879-0429}, mesh = {Carbon Isotopes/*analysis ; Isotope Labeling/*methods ; Plant Roots/*metabolism/microbiology ; Plants/*metabolism/microbiology ; *Soil Microbiology ; }, abstract = {Microbial communities associated with a plant host, constituting a holobiont, affect the physiology and growth of the plant via metabolites that are mainly derived from their photosynthates. The structure and function of active microbial communities that assimilate root exudates can be tracked by using stable isotope probing (SIP) approaches. This article reviews results from ongoing SIP research in plant-microbe interactions, with a specific focus on investigating the fate of fresh and recalcitrant carbon in the rhizosphere with 13C enriched-root exudates, in addition to identifying key players in carbon cycling. Finally, we discuss new SIP applications that have the potential to identify novel enzymes implicated in rhizoremediation or plant genes dedicated to root exudation by combining SIP approaches and genome wide associations studies.}, }
@article {pmid27014194, year = {2016}, author = {Ding, JY and Shiu, JH and Chen, WM and Chiang, YR and Tang, SL}, title = {Genomic Insight into the Host-Endosymbiont Relationship of Endozoicomonas montiporae CL-33(T) with its Coral Host.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {251}, doi = {10.3389/fmicb.2016.00251}, pmid = {27014194}, issn = {1664-302X}, abstract = {The bacterial genus Endozoicomonas was commonly detected in healthy corals in many coral-associated bacteria studies in the past decade. Although, it is likely to be a core member of coral microbiota, little is known about its ecological roles. To decipher potential interactions between bacteria and their coral hosts, we sequenced and investigated the first culturable endozoicomonal bacterium from coral, the E. montiporae CL-33(T). Its genome had potential sign of ongoing genome erosion and gene exchange with its host. Testosterone degradation and type III secretion system are commonly present in Endozoicomonas and may have roles to recognize and deliver effectors to their hosts. Moreover, genes of eukaryotic ephrin ligand B2 are present in its genome; presumably, this bacterium could move into coral cells via endocytosis after binding to coral's Eph receptors. In addition, 7,8-dihydro-8-oxoguanine triphosphatase and isocitrate lyase are possible type III secretion effectors that might help coral to prevent mitochondrial dysfunction and promote gluconeogenesis, especially under stress conditions. Based on all these findings, we inferred that E. montiporae was a facultative endosymbiont that can recognize, translocate, communicate and modulate its coral host.}, }
@article {pmid26979110, year = {2016}, author = {Greer, R and Dong, X and Morgun, A and Shulzhenko, N}, title = {Investigating a holobiont: Microbiota perturbations and transkingdom networks.}, journal = {Gut microbes}, volume = {7}, number = {2}, pages = {126-135}, doi = {10.1080/19490976.2015.1128625}, pmid = {26979110}, issn = {1949-0984}, support = {R01 DK103761/DK/NIDDK NIH HHS/United States ; U01 AI109695/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/genetics/metabolism ; Bacterial Infections/*microbiology ; Computational Biology ; Host-Pathogen Interactions/*drug effects ; Humans ; Microbiota/*drug effects ; }, abstract = {The scientific community has recently come to appreciate that, rather than existing as independent organisms, multicellular hosts and their microbiota comprise a complex evolving superorganism or metaorganism, termed a holobiont. This point of view leads to a re-evaluation of our understanding of different physiological processes and diseases. In this paper we focus on experimental and computational approaches which, when combined in one study, allowed us to dissect mechanisms (traditionally named host-microbiota interactions) regulating holobiont physiology. Specifically, we discuss several approaches for microbiota perturbation, such as use of antibiotics and germ-free animals, including advantages and potential caveats of their usage. We briefly review computational approaches to characterize the microbiota and, more importantly, methods to infer specific components of microbiota (such as microbes or their genes) affecting host functions. One such approach called transkingdom network analysis has been recently developed and applied in our study. (1) Finally, we also discuss common methods used to validate the computational predictions of host-microbiota interactions using in vitro and in vivo experimental systems.}, }
@article {pmid26953605, year = {2016}, author = {Glasl, B and Herndl, GJ and Frade, PR}, title = {The microbiome of coral surface mucus has a key role in mediating holobiont health and survival upon disturbance.}, journal = {The ISME journal}, volume = {10}, number = {9}, pages = {2280-2292}, doi = {10.1038/ismej.2016.9}, pmid = {26953605}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*microbiology/physiology ; Bacteria/genetics/growth &amp; development/*isolation &amp; purification ; *Biodiversity ; Coral Reefs ; DNA, Ribosomal/chemistry/genetics ; *Microbiota ; Sequence Analysis, DNA ; }, abstract = {Microbes are well-recognized members of the coral holobiont. However, little is known about the short-term dynamics of mucus-associated microbial communities under natural conditions and after disturbances, and how these dynamics relate to the host's health. Here we examined the natural variability of prokaryotic communities (based on 16S ribosomal RNA gene amplicon sequencing) associating with the surface mucus layer (SML) of Porites astreoides, a species exhibiting cyclical mucus aging and shedding. Shifts in the prokaryotic community composition during mucus aging led to the prevalence of opportunistic and potentially pathogenic bacteria (Verrucomicrobiaceae and Vibrionaceae) in aged mucus and to a twofold increase in prokaryotic abundance. After the release of aged mucus sheets, the community reverted to its original state, dominated by Endozoicimonaceae and Oxalobacteraceae. Furthermore, we followed the fate of the coral holobiont upon depletion of its natural mucus microbiome through antibiotics treatment. After re-introduction to the reef, healthy-looking microbe-depleted corals started exhibiting clear signs of bleaching and necrosis. Recovery versus mortality of the P. astreoides holobiont was related to the degree of change in abundance distribution of the mucus microbiome. We conclude that the natural prokaryotic community inhabiting the coral SML contributes to coral health and that cyclical mucus shedding has a key role in coral microbiome dynamics.}, }
@article {pmid26926518, year = {2016}, author = {Ryu, T and Seridi, L and Moitinho-Silva, L and Oates, M and Liew, YJ and Mavromatis, C and Wang, X and Haywood, A and Lafi, FF and Kupresanin, M and Sougrat, R and Alzahrani, MA and Giles, E and Ghosheh, Y and Schunter, C and Baumgarten, S and Berumen, ML and Gao, X and Aranda, M and Foret, S and Gough, J and Voolstra, CR and Hentschel, U and Ravasi, T}, title = {Hologenome analysis of two marine sponges with different microbiomes.}, journal = {BMC genomics}, volume = {17}, number = {}, pages = {158}, doi = {10.1186/s12864-016-2501-0}, pmid = {26926518}, issn = {1471-2164}, support = {BB/G022771/1//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {Animals ; Genome ; High-Throughput Nucleotide Sequencing ; Microbiota/*genetics ; Models, Genetic ; Molecular Sequence Annotation ; Porifera/*genetics/*microbiology ; Receptors, Scavenger/genetics ; Sequence Analysis, DNA ; Symbiosis ; Transcriptome ; }, abstract = {BACKGROUND: Sponges (Porifera) harbor distinct microbial consortia within their mesohyl interior. We herein analysed the hologenomes of Stylissa carteri and Xestospongia testudinaria, which notably differ in their microbiome content.<br><br>RESULTS: Our analysis revealed that S. carteri has an expanded repertoire of immunological domains, specifically Scavenger Receptor Cysteine-Rich (SRCR)-like domains, compared to X. testudinaria. On the microbial side, metatranscriptome analyses revealed an overrepresentation of potential symbiosis-related domains in X. testudinaria.<br><br>CONCLUSIONS: Our findings provide genomic insights into the molecular mechanisms underlying host-symbiont coevolution and may serve as a roadmap for future hologenome analyses.}, }
@article {pmid26925036, year = {2016}, author = {Zozaya-Valdés, E and Roth-Schulze, AJ and Thomas, T}, title = {Effects of Temperature Stress and Aquarium Conditions on the Red Macroalga Delisea pulchra and its Associated Microbial Community.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {161}, doi = {10.3389/fmicb.2016.00161}, pmid = {26925036}, issn = {1664-302X}, abstract = {In recent years, there has been an increase in the rate and severity of diseases affecting habitat-forming marine organisms, such as corals, sponges, and macroalgae. Delisea pulchra is a temperate red macroalga that suffers from a bleaching disease that is more frequent during summer, when seawater temperatures are elevated and the alga's chemical defense is weakened. A bacterial cause for the disease is implied by previous studies showing that some isolated strains can cause bleaching in vitro and that host-associated microbial communities are distinct between diseased and healthy individuals. However, nothing is known about the successional events in the microbial community that occur during the development of the disease. To study this aspect in the future, we aimed here to develop an experimental setup to study the bleaching disease in a controllable aquarium environment. Application of a temperature stress (up to 27°C) did not cause a clear and consistent pattern of bleaching, suggesting that temperature alone might not be the only or main factor to cause the disease. The results also showed that the aquarium conditions alone are sufficient to produce bleaching symptoms. Microbial community analysis based on 16S rRNA gene fingerprinting and sequencing showed significant changes after 15 days in the aquarium, indicating that the native microbial associates of D. pulchra are not stably maintained. Microbial taxa that were enriched in the aquarium-held D. pulchra thalli, however, did not match on a taxonomic level those that have been found to be enriched in natural bleaching events. Together our observations indicate that environmental factors, other than the ones investigated here, might drive the bleaching disease in D. pulchra and that the aquarium conditions have substantial impact on the alga-associated microbiome.}, }
@article {pmid26904096, year = {2016}, author = {Negri, I and Jablonka, E}, title = {Editorial: Epigenetics as a Deep Intimate Dialogue between Host and Symbionts.}, journal = {Frontiers in genetics}, volume = {7}, number = {}, pages = {7}, doi = {10.3389/fgene.2016.00007}, pmid = {26904096}, issn = {1664-8021}, }
@article {pmid26904020, year = {2016}, author = {Fonseca-García, C and Coleman-Derr, D and Garrido, E and Visel, A and Tringe, SG and Partida-Martínez, LP}, title = {The Cacti Microbiome: Interplay between Habitat-Filtering and Host-Specificity.}, journal = {Frontiers in microbiology}, volume = {7}, number = {}, pages = {150}, doi = {10.3389/fmicb.2016.00150}, pmid = {26904020}, issn = {1664-302X}, abstract = {Cactaceae represents one of the most species-rich families of succulent plants native to arid and semi-arid ecosystems, yet the associations Cacti establish with microorganisms and the rules governing microbial community assembly remain poorly understood. We analyzed the composition, diversity, and factors influencing above- and below-ground bacterial, archaeal, and fungal communities associated with two native and sympatric Cacti species: Myrtillocactus geometrizans and Opuntia robusta. Phylogenetic profiling showed that the composition and assembly of microbial communities associated with Cacti were primarily influenced by the plant compartment; plant species, site, and season played only a minor role. Remarkably, bacterial, and archaeal diversity was higher in the phyllosphere than in the rhizosphere of Cacti, while the opposite was true for fungi. Semi-arid soils exhibited the highest levels of microbial diversity whereas the stem endosphere the lowest. Despite their taxonomic distance, M. geometrizans and O. robusta shared most microbial taxa in all analyzed compartments. Influence of the plant host did only play a larger role in the fungal communities of the stem endosphere. These results suggest that fungi establish specific interactions with their host plant inside the stem, whereas microbial communities in the other plant compartments may play similar functional roles in these two species. Biochemical and molecular characterization of seed-borne bacteria of Cacti supports the idea that these microbial symbionts may be vertically inherited and could promote plant growth and drought tolerance for the fitness of the Cacti holobiont. We envision this knowledge will help improve and sustain agriculture in arid and semi-arid regions of the world.}, }
@article {pmid26865302, year = {2016}, author = {Gardner, SG and Nielsen, DA and Laczka, O and Shimmon, R and Beltran, VH and Ralph, PJ and Petrou, K}, title = {Dimethylsulfoniopropionate, superoxide dismutase and glutathione as stress response indicators in three corals under short-term hyposalinity stress.}, journal = {Proceedings. Biological sciences}, volume = {283}, number = {1824}, pages = {}, doi = {10.1098/rspb.2015.2418}, pmid = {26865302}, issn = {1471-2954}, mesh = {Animals ; Anthozoa/*physiology ; Dinoflagellida/physiology ; Glutathione/*metabolism ; *Salinity ; Species Specificity ; Stress, Physiological ; Sulfonium Compounds/*metabolism ; Superoxide Dismutase/*metabolism ; Symbiosis ; }, abstract = {Corals are among the most active producers of dimethylsulfoniopropionate (DMSP), a key molecule in marine sulfur cycling, yet the specific physiological role of DMSP in corals remains elusive. Here, we examine the oxidative stress response of three coral species (Acropora millepora, Stylophora pistillata and Pocillopora damicornis) and explore the antioxidant role of DMSP and its breakdown products under short-term hyposalinity stress. Symbiont photosynthetic activity declined with hyposalinity exposure in all three reef-building corals. This corresponded with the upregulation of superoxide dismutase and glutathione in the animal host of all three species. For the symbiont component, there were differences in antioxidant regulation, demonstrating differential responses to oxidative stress between the Symbiodinium subclades. Of the three coral species investigated, only A. millepora provided any evidence of the role of DMSP in the oxidative stress response. Our study reveals variability in antioxidant regulation in corals and highlights the influence life-history traits, and the subcladal differences can have on coral physiology. Our data expand on the emerging understanding of the role of DMSP in coral stress regulation and emphasizes the importance of exploring both the host and symbiont responses for defining the threshold of the coral holobiont to hyposalinity stress.}, }
@article {pmid26843939, year = {2016}, author = {Rouzé, H and Lecellier, G and Saulnier, D and Berteaux-Lecellier, V}, title = {Symbiodinium clades A and D differentially predispose Acropora cytherea to disease and Vibrio spp. colonization.}, journal = {Ecology and evolution}, volume = {6}, number = {2}, pages = {560-572}, doi = {10.1002/ece3.1895}, pmid = {26843939}, issn = {2045-7758}, abstract = {Coral disease outbreaks have increased over the last three decades, but their causal agents remain mostly unclear (e.g., bacteria, viruses, fungi, protists). This study details a 14-month-long survey of coral colonies in which observations of the development of disease was observed in nearly half of the sampled colonies. A bimonthly qPCR method was used to quantitatively and qualitatively evaluate Symbiodinium assemblages of tagged colonies, and to detect the presence of Vibrio spp. Firstly, our data showed that predisposition to disease development in general, and, more specifically, infection by Vibrio spp. in Acropora cytherea depended on which clades of Symbiodinium were harbored. In both cases, harboring clade D rather than A was beneficial to the coral host. Secondly, the detection of Vibrio spp. in only colonies that developed disease strongly suggests opportunistic traits of the bacteria. Finally, even if sporadic cases of switching and probably shuffling were observed, this long-term survey does not suggest specific-clade recruitment in response to stressors. Altogether, our results demonstrate that the fitness of the coral holobiont depends on its initial consortium of Symbiodinium, which is distinct among colonies, rather than a temporary adaptation achieved through acquiring different Symbiodinium clades.}, }
@article {pmid26840035, year = {2016}, author = {Röthig, T and Ochsenkühn, MA and Roik, A and van der Merwe, R and Voolstra, CR}, title = {Long-term salinity tolerance is accompanied by major restructuring of the coral bacterial microbiome.}, journal = {Molecular ecology}, volume = {25}, number = {6}, pages = {1308-1323}, doi = {10.1111/mec.13567}, pmid = {26840035}, issn = {1365-294X}, mesh = {Acclimatization/physiology ; Animals ; Anthozoa/*microbiology/*physiology ; Bacteria/classification ; DNA, Bacterial/genetics ; *Microbiota ; Photosynthesis ; RNA, Ribosomal, 16S/genetics ; Salinity ; *Salt-Tolerance ; Symbiosis ; }, abstract = {Scleractinian corals are assumed to be stenohaline osmoconformers, although they are frequently subjected to variations in seawater salinity due to precipitation, freshwater run-off and other processes. Observed responses to altered salinity levels include differences in photosynthetic performance, respiration and increased bleaching and mortality of the coral host and its algal symbiont, but a study looking at bacterial community changes is lacking. Here, we exposed the coral Fungia granulosa to strongly increased salinity levels in short- and long-term experiments to disentangle temporal and compartment effects of the coral holobiont (i.e. coral host, symbiotic algae and associated bacteria). Our results show a significant reduction in calcification and photosynthesis, but a stable microbiome after short-term exposure to high-salinity levels. By comparison, long-term exposure yielded unchanged photosynthesis levels and visually healthy coral colonies indicating long-term acclimation to high-salinity levels that were accompanied by a major coral microbiome restructuring. Importantly, a bacterium in the family Rhodobacteraceae was succeeded by Pseudomonas veronii as the numerically most abundant taxon. Further, taxonomy-based functional profiling indicates a shift in the bacterial community towards increased osmolyte production, sulphur oxidation and nitrogen fixation. Our study highlights that bacterial community composition in corals can change within days to weeks under altered environmental conditions, where shifts in the microbiome may enable adjustment of the coral to a more advantageous holobiont composition.}, }
@article {pmid26818718, year = {2016}, author = {Dessaux, Y and Grandclément, C and Faure, D}, title = {Engineering the Rhizosphere.}, journal = {Trends in plant science}, volume = {21}, number = {3}, pages = {266-278}, doi = {10.1016/j.tplants.2016.01.002}, pmid = {26818718}, issn = {1878-4372}, mesh = {Botany/*methods ; Microbiota ; Plants/microbiology ; *Rhizosphere ; Soil ; Soil Microbiology ; }, abstract = {All components of the rhizosphere can be engineered to promote plant health and growth, two features that strongly depend upon the interactions of living organisms with their environment. This review describes the progress in plant and microbial molecular genetics and ecology that has led to a wealth of potential applications. Recent efforts especially deal with the plant defense machinery that is instrumental in engineering plant resistance to biotic stresses. Another approach involves microbial population engineering rather than single strain engineering. More generally, the plants (and the associated microbes) are no longer seen as 'individual' but rather as a holobiont, in other words a unit of selection in evolution, a concept that holds great promise for future plant breeding programs.}, }
@article {pmid26788878, year = {2016}, author = {Agler, MT and Ruhe, J and Kroll, S and Morhenn, C and Kim, ST and Weigel, D and Kemen, EM}, title = {Microbial Hub Taxa Link Host and Abiotic Factors to Plant Microbiome Variation.}, journal = {PLoS biology}, volume = {14}, number = {1}, pages = {e1002352}, doi = {10.1371/journal.pbio.1002352}, pmid = {26788878}, issn = {1545-7885}, mesh = {Arabidopsis/genetics/*microbiology ; Bacteria ; Basidiomycota/physiology ; Endophytes/physiology ; *Microbiota ; Oomycetes/physiology ; }, abstract = {Plant-associated microorganisms have been shown to critically affect host physiology and performance, suggesting that evolution and ecology of plants and animals can only be understood in a holobiont (host and its associated organisms) context. Host-associated microbial community structures are affected by abiotic and host factors, and increased attention is given to the role of the microbiome in interactions such as pathogen inhibition. However, little is known about how these factors act on the microbial community, and especially what role microbe-microbe interaction dynamics play. We have begun to address this knowledge gap for phyllosphere microbiomes of plants by simultaneously studying three major groups of Arabidopsis thaliana symbionts (bacteria, fungi and oomycetes) using a systems biology approach. We evaluated multiple potential factors of microbial community control: we sampled various wild A. thaliana populations at different times, performed field plantings with different host genotypes, and implemented successive host colonization experiments under lab conditions where abiotic factors, host genotype, and pathogen colonization was manipulated. Our results indicate that both abiotic factors and host genotype interact to affect plant colonization by all three groups of microbes. Considering microbe-microbe interactions, however, uncovered a network of interkingdom interactions with significant contributions to community structure. As in other scale-free networks, a small number of taxa, which we call microbial &quot;hubs,&quot; are strongly interconnected and have a severe effect on communities. By documenting these microbe-microbe interactions, we uncover an important mechanism explaining how abiotic factors and host genotypic signatures control microbial communities. In short, they act directly on &quot;hub&quot; microbes, which, via microbe-microbe interactions, transmit the effects to the microbial community. We analyzed two &quot;hub&quot; microbes (the obligate biotrophic oomycete pathogen Albugo and the basidiomycete yeast fungus Dioszegia) more closely. Albugo had strong effects on epiphytic and endophytic bacterial colonization. Specifically, alpha diversity decreased and beta diversity stabilized in the presence of Albugo infection, whereas they otherwise varied between plants. Dioszegia, on the other hand, provided evidence for direct hub interaction with phyllosphere bacteria. The identification of microbial &quot;hubs&quot; and their importance in phyllosphere microbiome structuring has crucial implications for plant-pathogen and microbe-microbe research and opens new entry points for ecosystem management and future targeted biocontrol. The revelation that effects can cascade through communities via &quot;hub&quot; microbes is important to understand community structure perturbations in parallel fields including human microbiomes and bioprocesses. In particular, parallels to human microbiome &quot;keystone&quot; pathogens and microbes open new avenues of interdisciplinary research that promise to better our understanding of functions of host-associated microbiomes.}, }
@article {pmid26779145, year = {2015}, author = {Lachnit, T and Thomas, T and Steinberg, P}, title = {Expanding our Understanding of the Seaweed Holobiont: RNA Viruses of the Red Alga Delisea pulchra.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1489}, doi = {10.3389/fmicb.2015.01489}, pmid = {26779145}, issn = {1664-302X}, abstract = {Marine seaweeds are holobionts comprised of the macroalgal hosts and their associated microbiota. While the composition of the bacterial component of seaweed microbiomes is increasingly studied, almost nothing is known about the presence, diversity and composition of viruses in macroalgae in situ. In this study, we characterize for the first time the viruses associated with a red macroalga, Delisea pulchra. Using transmission electron microscopy we identified diverse morphotypes of virus-like particles in D. pulchra ranging from icosahedral to bacilliform to coiled pleomorphic as well as bacteriophages. Virome sequencing revealed the presence of a diverse group of dsRNA viruses affiliated to the genus Totivirus, known to infect plant pathogenic fungi. We further identified a ssRNA virus belonging to the order Picornavirales with a close phylogenetic relationship to a pathogenic virus infecting marine diatoms. The results of this study shed light on a so far neglected part of the seaweed holobiont, and suggest that some of the identified viruses may be possible pathogens for a host that is already known to be significantly impacted by bacterial infections.}, }
@article {pmid26763678, year = {2016}, author = {Hacquard, S}, title = {Disentangling the factors shaping microbiota composition across the plant holobiont.}, journal = {The New phytologist}, volume = {209}, number = {2}, pages = {454-457}, doi = {10.1111/nph.13760}, pmid = {26763678}, issn = {1469-8137}, mesh = {Bacteria/genetics ; *Microbiota ; *Plants ; RNA, Ribosomal, 16S ; Rhizosphere ; Soil Microbiology ; }, }
@article {pmid26759710, year = {2016}, author = {Lu, HL and Price, DR and Wikramanayake, A and Chang, CC and Wilson, AC}, title = {Ontogenetic differences in localization of glutamine transporter ApGLNT1 in the pea aphid demonstrate that mechanisms of host/symbiont integration are not similar in the maternal versus embryonic bacteriome.}, journal = {EvoDevo}, volume = {7}, number = {}, pages = {1}, doi = {10.1186/s13227-015-0038-y}, pmid = {26759710}, issn = {2041-9139}, abstract = {BACKGROUND: Obligate intracellular symbionts of insects are metabolically and developmentally integrated with their hosts. Typically, reproduction fails in many insect nutritional endosymbioses when host insects are cured of their bacterial symbionts, and yet remarkably little is known about the processes that developmentally integrate host and symbiont. Here in the best studied insect obligate intracellular symbiosis, that of the pea aphid, Acyrthosiphon pisum, with the gammaproteobacterium Buchnera aphidicola, we tracked the expression and localization of amino acid transporter ApGLNT1 gene products during asexual embryogenesis. Recently being characterized as a glutamine transporter, ApGLNT1 has been proposed to be a key regulator of amino acid biosynthesis in A. pisum bacteriocytes. To determine when this important mediator of the symbiosis becomes expressed in aphid embryonic bacteriocytes, we applied whole-mount in situ hybridization and fluorescent immunostaining with a specific anti-ApGLNT1 antibody to detect the temporal and spatial expression of ApGLNT1 gene products during asexual embryogenesis.<br><br>RESULTS: During embryogenesis, ApGLNT1 mRNA and protein localize to the follicular epithelium that surrounds parthenogenetic viviparous embryos, where we speculate that it functions to supply developing embryos with glutamine from maternal hemolymph. Unexpectedly, in the embryonic bacteriome ApGLNT1 protein does not localize to the membrane of bacteriocytes, a pattern that leads us to conclude that the regulation of amino acid metabolism in the embryonic bacteriome mechanistically differs from that in the maternal bacteriome. Paralleling our earlier report of punctate cytoplasmic localization of ApGLNT1 in maternal bacteriocytes, we find ApGLNT1 protein localizing as cytoplasmic puncta throughout development in association with Buchnera.<br><br>CONCLUSIONS: Our work that documents ontogenetic shifts in the localization of ApGLNT1 protein in the host bacteriome demonstrates that maternal and embryonic bacteriomes are not equivalent. Significantly, the persistent punctate cytoplasmic localization of ApGLNT1 in association with Buchnera in embryos prior to bacteriocyte formation and later in both embryonic and maternal bacteriomes suggests that ApGLNT1 plays multiple roles in this symbiosis, roles that include amino acid transport and possibly nutrient sensing.}, }
@article {pmid26749251, year = {2016}, author = {Moore, A}, title = {Getting fat from an inflamed relationship? The revenge of the holobiont.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {38}, number = {2}, pages = {119}, doi = {10.1002/bies.201600001}, pmid = {26749251}, issn = {1521-1878}, mesh = {Anti-Bacterial Agents/adverse effects ; Food Additives/adverse effects ; Gastrointestinal Microbiome/*physiology ; Humans ; Inflammation/*etiology/*microbiology ; Intestines/microbiology ; Obesity/*etiology/*microbiology ; }, }
@article {pmid26739062, year = {2016}, author = {Poutahidis, T and Erdman, SE}, title = {Commensal bacteria modulate the tumor microenvironment.}, journal = {Cancer letters}, volume = {380}, number = {1}, pages = {356-358}, doi = {10.1016/j.canlet.2015.12.028}, pmid = {26739062}, issn = {1872-7980}, support = {R01 CA108854/CA/NCI NIH HHS/United States ; U01 CA164337/CA/NCI NIH HHS/United States ; }, mesh = {Animals ; Bacteria/immunology/metabolism/*pathogenicity ; *Cell Transformation, Neoplastic/immunology/metabolism/pathology ; *Gastrointestinal Microbiome ; Host-Pathogen Interactions ; Humans ; Neoplasms/immunology/metabolism/*microbiology/pathology ; Risk Factors ; Signal Transduction ; Symbiosis ; *Tumor Microenvironment ; }, abstract = {It has been recently shown that gut microbes modulate whole host immune and hormonal factors impacting the fate of distant preneoplastic lesions toward malignancy or regression. This raises the possibility that the tumor microenvironment interacts with broader systemic microbial-immune networks. These accumulated findings suggest novel therapeutic opportunities for holobiont engineering in emerging tumor microenvironments.}, }
@article {pmid26734000, year = {2015}, author = {Martin, M and Barbeyron, T and Martin, R and Portetelle, D and Michel, G and Vandenbol, M}, title = {The Cultivable Surface Microbiota of the Brown Alga Ascophyllum nodosum is Enriched in Macroalgal-Polysaccharide-Degrading Bacteria.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1487}, doi = {10.3389/fmicb.2015.01487}, pmid = {26734000}, issn = {1664-302X}, abstract = {Bacteria degrading algal polysaccharides are key players in the global carbon cycle and in algal biomass recycling. Yet the water column, which has been studied largely by metagenomic approaches, is poor in such bacteria and their algal-polysaccharide-degrading enzymes. Even more surprisingly, the few published studies on seaweed-associated microbiomes have revealed low abundances of such bacteria and their specific enzymes. However, as macroalgal cell-wall polysaccharides do not accumulate in nature, these bacteria and their unique polysaccharidases must not be that uncommon. We, therefore, looked at the polysaccharide-degrading activity of the cultivable bacterial subpopulation associated with Ascophyllum nodosum. From A. nodosum triplicates, 324 bacteria were isolated and taxonomically identified. Out of these isolates, 78 (~25%) were found to act on at least one tested algal polysaccharide (agar, ι- or κ-carrageenan, or alginate). The isolates &quot;active&quot; on algal-polysaccharides belong to 11 genera: Cellulophaga, Maribacter, Algibacter, and Zobellia in the class Flavobacteriia (41) and Pseudoalteromonas, Vibrio, Cobetia, Shewanella, Colwellia, Marinomonas, and Paraglaceciola in the class Gammaproteobacteria (37). A major part represents likely novel species. Different proportions of bacterial phyla and classes were observed between the isolated cultivable subpopulation and the total microbial community previously identified on other brown algae. Here, Bacteroidetes and Gammaproteobacteria were found to be the most abundant and some phyla (as Planctomycetes and Cyanobacteria) frequently encountered on brown algae weren't identified. At a lower taxonomic level, twelve genera, well-known to be associated with algae (with the exception for Colwellia), were consistently found on all three A. nosodum samples. Even more interesting, 9 of the 11 above mentioned genera containing polysaccharolytic isolates were predominant in this common core. The cultivable fraction of the bacterial community associated with A. nodosum is, thus, significantly enriched in macroalgal-polysaccharide-degrading bacteria and these bacteria seem important for the seaweed holobiont even though they are under-represented in alga-associated microbiome studies.}, }
@article {pmid26696324, year = {2016}, author = {Lema, KA and Clode, PL and Kilburn, MR and Thornton, R and Willis, BL and Bourne, DG}, title = {Imaging the uptake of nitrogen-fixing bacteria into larvae of the coral Acropora millepora.}, journal = {The ISME journal}, volume = {10}, number = {7}, pages = {1804-1808}, doi = {10.1038/ismej.2015.229}, pmid = {26696324}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*microbiology ; In Situ Hybridization, Fluorescence ; Larva ; Nitrogen/*metabolism ; Nitrogen Fixation ; Nitrogen-Fixing Bacteria/*metabolism ; }, abstract = {Diazotrophic bacteria are instrumental in generating biologically usable forms of nitrogen by converting abundant dinitrogen gas (N2) into available forms, such as ammonium. Although nitrogen is crucial for coral growth, direct observation of associations between diazotrophs and corals has previously been elusive. We applied fluorescence in situ hybridization (FISH) and nanoscale secondary ion mass spectrometry to observe the uptake of (15)N-enriched diazotrophic Vibrio sp. isolated from Acropora millepora into conspecific coral larvae. Incorporation of Vibrio sp. cells was observed in coral larvae after 4-h incubation with enriched bacteria. Uptake was restricted to the aboral epidermis of larvae, where Vibrio cells clustered in elongated aggregations. Other bacterial associates were also observed in epidermal areas in FISH analyses. Although the fate and role of these bacteria requires additional investigation, this study describes a powerful approach to further explore cell associations and nutritional pathways in the early life stages of the coral holobiont.}, }
@article {pmid26659364, year = {2015}, author = {Kemp, DW and Rivers, AR and Kemp, KM and Lipp, EK and Porter, JW and Wares, JP}, title = {Spatial Homogeneity of Bacterial Communities Associated with the Surface Mucus Layer of the Reef-Building Coral Acropora palmata.}, journal = {PloS one}, volume = {10}, number = {12}, pages = {e0143790}, doi = {10.1371/journal.pone.0143790}, pmid = {26659364}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*microbiology/physiology ; Bacteria/genetics/growth &amp; development/*isolation &amp; purification ; Biodiversity ; Coral Reefs ; Florida ; *Microbiota ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Seawater/microbiology ; Sequence Analysis, RNA ; }, abstract = {Coral surface mucus layer (SML) microbiota are critical components of the coral holobiont and play important roles in nutrient cycling and defense against pathogens. We sequenced 16S rRNA amplicons to examine the structure of the SML microbiome within and between colonies of the threatened Caribbean reef-building coral Acropora palmata in the Florida Keys. Samples were taken from three spatially distinct colony regions--uppermost (high irradiance), underside (low irradiance), and the colony base--representing microhabitats that vary in irradiance and water flow. Phylogenetic diversity (PD) values of coral SML bacteria communities were greater than surrounding seawater and lower than adjacent sediment. Bacterial diversity and community composition was consistent among the three microhabitats. Cyanobacteria, Bacteroidetes, Alphaproteobacteria, and Proteobacteria, respectively were the most abundant phyla represented in the samples. This is the first time spatial variability of the surface mucus layer of A. palmata has been studied. Homogeneity in the microbiome of A. palmata contrasts with SML heterogeneity found in other Caribbean corals. These findings suggest that, during non-stressful conditions, host regulation of SML microbiota may override diverse physiochemical influences induced by the topographical complexity of A. palmata. Documenting the spatial distribution of SML microbes is essential to understanding the functional roles these microorganisms play in coral health and adaptability to environmental perturbations.}, }
@article {pmid26658023, year = {2015}, author = {Fragoso Ados Santos, H and Duarte, GA and Rachid, CT and Chaloub, RM and Calderon, EN and Marangoni, LF and Bianchini, A and Nudi, AH and do Carmo, FL and van Elsas, JD and Rosado, AS and Castro, CB and Peixoto, RS}, title = {Impact of oil spills on coral reefs can be reduced by bioremediation using probiotic microbiota.}, journal = {Scientific reports}, volume = {5}, number = {}, pages = {18268}, doi = {10.1038/srep18268}, pmid = {26658023}, issn = {2045-2322}, mesh = {Bacteria/classification/genetics/metabolism ; *Biodegradation, Environmental ; *Biotransformation ; *Coral Reefs ; Hydrocarbons/metabolism ; *Microbiota ; *Petroleum Pollution ; Photochemical Processes ; *Probiotics ; Water Pollutants, Chemical ; }, abstract = {Several anthropogenic factors, including contamination by oil spills, constitute a threat to coral reef health. Current methodologies to remediate polluted marine environments are based on the use of chemical dispersants; however, these can be toxic to the coral holobiont. In this study, a probiotic bacterial consortium was produced from the coral Mussismilia harttii and was trained to degrade water-soluble oil fractions (WSFs). Additionally, we assessed the effect of WSFs on the health of M. harttii in tanks and evaluated the bacterial consortium as a bioremediation agent. The consortium was responsible for the highly efficient degradation of petroleum hydrocarbons, and it minimised the effects of WSFs on coral health, as indicated by raised photosynthetic efficiencies. Moreover, the impact of WSFs on the coral microbiome was diminished by the introduced bacterial consortium. Following introduction, the bacterial consortium thus had a dual function, i.e promoting oil WSF degradation and improving coral health with its probiotic features.}, }
@article {pmid26640464, year = {2015}, author = {Wong, AC and Holmes, A and Ponton, F and Lihoreau, M and Wilson, K and Raubenheimer, D and Simpson, SJ}, title = {Behavioral Microbiomics: A Multi-Dimensional Approach to Microbial Influence on Behavior.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1359}, doi = {10.3389/fmicb.2015.01359}, pmid = {26640464}, issn = {1664-302X}, abstract = {The role of microbes as a part of animal systems has historically been an under-appreciated aspect of animal life histories. Recently, evidence has emerged that microbes have wide-ranging influences on animal behavior. Elucidating the complex relationships between host-microbe interactions and behavior requires an expanded ecological perspective, involving the host, the microbiome and the environment; which, in combination, is termed the holobiont. We begin by seeking insights from the literature on host-parasite interactions, then expand to consider networks of interactions between members of the microbial community. A central aspect of the environment is host nutrition. We describe how interactions between the nutrient environment, the metabolic and behavioral responses of the host and the microbiome can be studied using an integrative framework called nutritional geometry, which integrates and maps multiple aspects of the host and microbial response in multidimensional nutrient intake spaces.}, }
@article {pmid26636661, year = {2015}, author = {Moran, NA and Sloan, DB}, title = {The Hologenome Concept: Helpful or Hollow?.}, journal = {PLoS biology}, volume = {13}, number = {12}, pages = {e1002311}, doi = {10.1371/journal.pbio.1002311}, pmid = {26636661}, issn = {1545-7885}, support = {GM108477/GM/NIGMS NIH HHS/United States ; }, mesh = {Animals ; Biological Evolution ; *Genome ; *Genome, Microbial ; Genomics/*methods/trends ; Humans ; *Microbiota ; *Models, Genetic ; Symbiosis ; Terminology as Topic ; }, abstract = {With the increasing appreciation for the crucial roles that microbial symbionts play in the development and fitness of plant and animal hosts, there has been a recent push to interpret evolution through the lens of the &quot;hologenome&quot;--the collective genomic content of a host and its microbiome. But how symbionts evolve and, particularly, whether they undergo natural selection to benefit hosts are complex issues that are associated with several misconceptions about evolutionary processes in host-associated microbial communities. Microorganisms can have intimate, ancient, and/or mutualistic associations with hosts without having undergone natural selection to benefit hosts. Likewise, observing host-specific microbial community composition or greater community similarity among more closely related hosts does not imply that symbionts have coevolved with hosts, let alone that they have evolved for the benefit of the host. Although selection at the level of the symbiotic community, or hologenome, occurs in some cases, it should not be accepted as the null hypothesis for explaining features of host-symbiont associations.}, }
@article {pmid26598731, year = {2016}, author = {Eisthen, HL and Theis, KR}, title = {Animal-microbe interactions and the evolution of nervous systems.}, journal = {Philosophical transactions of the Royal Society of London. Series B, Biological sciences}, volume = {371}, number = {1685}, pages = {20150052}, doi = {10.1098/rstb.2015.0052}, pmid = {26598731}, issn = {1471-2970}, mesh = {Animals ; *Bacteria ; Behavior, Animal ; *Biological Evolution ; Central Nervous System/*anatomy &amp; histology/*physiology ; Invertebrates/anatomy &amp; histology/*microbiology/physiology ; Vertebrates/anatomy &amp; histology/*microbiology/physiology ; }, abstract = {Animals ubiquitously interact with environmental and symbiotic microbes, and the effects of these interactions on animal physiology are currently the subject of intense interest. Nevertheless, the influence of microbes on nervous system evolution has been largely ignored. We illustrate here how taking microbes into account might enrich our ideas about the evolution of nervous systems. For example, microbes are involved in animals' communicative, defensive, predatory and dispersal behaviours, and have likely influenced the evolution of chemo- and photosensory systems. In addition, we speculate that the need to regulate interactions with microbes at the epithelial surface may have contributed to the evolutionary internalization of the nervous system.}, }
@article {pmid26568407, year = {2016}, author = {Mushegian, AA and Ebert, D}, title = {Rethinking &quot;mutualism&quot; in diverse host-symbiont communities.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {38}, number = {1}, pages = {100-108}, doi = {10.1002/bies.201500074}, pmid = {26568407}, issn = {1521-1878}, mesh = {Bacterial Physiological Phenomena/*genetics ; *Biological Evolution ; Ecosystem ; Eukaryota/genetics ; Microbiota/*genetics ; Symbiosis/*genetics ; }, abstract = {While examples of bacteria benefiting eukaryotes are increasingly documented, studies examining effects of eukaryote hosts on microbial fitness are rare. Beneficial bacteria are often called &quot;mutualistic&quot; even if mutual reciprocity of benefits has not been demonstrated and despite the plausibility of other explanations for these microbes' beneficial effects on host fitness. Furthermore, beneficial bacteria often occur in diverse communities, making mutualism both empirically and conceptually difficult to demonstrate. We suggest reserving the terms &quot;mutualism&quot; and &quot;parasitism&quot; for pairwise interactions where the relationship is largely independent of other species and can be verified by measuring the fitness effect experienced by both partners. In hosts with diverse microbial communities, we propose re-formulating some of the essential questions of symbiosis research - e.g. concerning specificity, transmission mode, and common evolutionary fates - as questions of community ecology and ecosystem function, allowing important biological interactions to be investigated without making assumptions about reciprocity. Understanding the fitness of host-associated bacteria is a crucial component of investigations into the role of microbes in eukaryote evolution.}, }
@article {pmid26556047, year = {2015}, author = {Shelburne, SA and Ajami, NJ and Chibucos, MC and Beird, HC and Tarrand, J and Galloway-Peña, J and Albert, N and Chemaly, RF and Ghantoji, SS and Marsh, L and Pemmaraju, N and Andreeff, M and Shpall, EJ and Wargo, JA and Rezvani, K and Alousi, A and Bruno, VM and Futreal, PA and Petrosino, JF and Kontoyiannis, DP}, title = {Implementation of a Pan-Genomic Approach to Investigate Holobiont-Infecting Microbe Interaction: A Case Report of a Leukemic Patient with Invasive Mucormycosis.}, journal = {PloS one}, volume = {10}, number = {11}, pages = {e0139851}, doi = {10.1371/journal.pone.0139851}, pmid = {26556047}, issn = {1932-6203}, support = {P30 CA016672/CA/NCI NIH HHS/United States ; R01AI089891/AI/NIAID NIH HHS/United States ; R01 CA061508/CA/NCI NIH HHS/United States ; U19 AI110820/AI/NIAID NIH HHS/United States ; U19AI110820/AI/NIAID NIH HHS/United States ; HHSN272200900009C//PHS HHS/United States ; HHSN272200900009C/AI/NIAID NIH HHS/United States ; R01 AI089891/AI/NIAID NIH HHS/United States ; }, mesh = {Antifungal Agents/therapeutic use ; Antineoplastic Combined Chemotherapy Protocols/adverse effects ; Chemotherapy-Induced Febrile Neutropenia ; Fungal Proteins/genetics ; Fungemia/microbiology ; Gastrointestinal Microbiome/*genetics ; *Genome, Fungal ; Host-Pathogen Interactions ; Humans ; Leukemia, Myeloid, Acute/*complications ; Male ; Middle Aged ; Mucor/*genetics/isolation &amp; purification ; Mucormycosis/drug therapy/*microbiology ; Neoplasm Proteins/genetics ; Onychomycosis/complications ; Opportunistic Infections/drug therapy/*microbiology ; }, abstract = {Disease can be conceptualized as the result of interactions between infecting microbe and holobiont, the combination of a host and its microbial communities. It is likely that genomic variation in the host, infecting microbe, and commensal microbiota are key determinants of infectious disease clinical outcomes. However, until recently, simultaneous, multiomic investigation of infecting microbe and holobiont components has rarely been explored. Herein, we characterized the infecting microbe, host, micro- and mycobiomes leading up to infection onset in a leukemia patient that developed invasive mucormycosis. We discovered that the patient was infected with a strain of the recently described Mucor velutinosus species which we determined was hypervirulent in a Drosophila challenge model and has a predisposition for skin dissemination. After completing the infecting M. velutinosus genome and genomes from four other Mucor species, comparative pathogenomics was performed and assisted in identifying 66 M. velutinosus-specific putatively secreted proteins, including multiple novel secreted aspartyl proteinases which may contribute to the unique clinical presentation of skin dissemination. Whole exome sequencing of the patient revealed multiple non-synonymous polymorphisms in genes critical to control of fungal proliferation, such as TLR6 and PTX3. Moreover, the patient had a non-synonymous polymorphism in the NOD2 gene and a missense mutation in FUT2, which have been linked to microbial dysbiosis and microbiome diversity maintenance during physiologic stress, respectively. In concert with host genetic polymorphism data, the micro- and mycobiome analyses revealed that the infection developed amid a dysbiotic microbiome with low α-diversity, dominated by staphylococci. Additionally, longitudinal mycobiome data showed that M. velutinosus DNA was detectable in oral samples preceding disease onset. Our genome-level study of the host-infecting microbe-commensal triad extends the concept of personalized genomic medicine to the holobiont-infecting microbe interface thereby offering novel opportunities for using synergistic genetic methods to increase understanding of infectious diseases pathogenesis and clinical outcomes.}, }
@article {pmid26555246, year = {2016}, author = {Hester, ER and Barott, KL and Nulton, J and Vermeij, MJ and Rohwer, FL}, title = {Stable and sporadic symbiotic communities of coral and algal holobionts.}, journal = {The ISME journal}, volume = {10}, number = {5}, pages = {1157-1169}, doi = {10.1038/ismej.2015.190}, pmid = {26555246}, issn = {1751-7370}, mesh = {Algorithms ; Animals ; Anthozoa/*microbiology ; Archaea/*classification ; Bacteria/classification ; DNA Barcoding, Taxonomic ; DNA, Ribosomal/analysis ; Environment ; Evolution, Molecular ; Fungi/classification ; *Microbiota ; Polymerase Chain Reaction ; Sequence Analysis, DNA ; Species Specificity ; *Symbiosis ; Viruses/classification ; }, abstract = {Coral and algal holobionts are assemblages of macroorganisms and microorganisms, including viruses, Bacteria, Archaea, protists and fungi. Despite a decade of research, it remains unclear whether these associations are spatial-temporally stable or species-specific. We hypothesized that conflicting interpretations of the data arise from high noise associated with sporadic microbial symbionts overwhelming signatures of stable holobiont members. To test this hypothesis, the bacterial communities associated with three coral species (Acropora rosaria, Acropora hyacinthus and Porites lutea) and two algal guilds (crustose coralline algae and turf algae) from 131 samples were analyzed using a novel statistical approach termed the Abundance-Ubiquity (AU) test. The AU test determines whether a given bacterial species would be present given additional sampling effort (that is, stable) versus those species that are sporadically associated with a sample. Using the AU test, we show that coral and algal holobionts have a high-diversity group of stable symbionts. Stable symbionts are not exclusive to one species of coral or algae. No single bacterial species was ubiquitously associated with one host, showing that there is not strict heredity of the microbiome. In addition to the stable symbionts, there was a low-diversity community of sporadic symbionts whose abundance varied widely across individual holobionts of the same species. Identification of these two symbiont communities supports the holobiont model and calls into question the hologenome theory of evolution.}, }
@article {pmid26547794, year = {2016}, author = {Berg, G and Rybakova, D and Grube, M and Köberl, M}, title = {The plant microbiome explored: implications for experimental botany.}, journal = {Journal of experimental botany}, volume = {67}, number = {4}, pages = {995-1002}, doi = {10.1093/jxb/erv466}, pmid = {26547794}, issn = {1460-2431}, support = {J 3638//Austrian Science Fund FWF/Austria ; }, mesh = {Botany/*trends ; *Microbiota ; Plants/*microbiology ; }, abstract = {The importance of microbial root inhabitants for plant growth and health was recognized as early as 100 years ago. Recent insights reveal a close symbiotic relationship between plants and their associated microorganisms, and high structural and functional diversity within plant microbiomes. Plants provide microbial communities with specific habitats, which can be broadly categorized as the rhizosphere, phyllosphere, and endosphere. Plant-associated microbes interact with their host in essential functional contexts. They can stimulate germination and growth, help plants fend off disease, promote stress resistance, and influence plant fitness. Therefore, plants have to be considered as metaorganisms within which the associated microbes usually outnumber the cells belonging to the plant host. The structure of the plant microbiome is determined by biotic and abiotic factors but follows ecological rules. Metaorganisms are co-evolved species assemblages. The metabolism and morphology of plants and their microbiota are intensively connected with each other, and the interplay of both maintains the functioning and fitness of the holobiont. Our study of the current literature shows that analysis of plant microbiome data has brought about a paradigm shift in our understanding of the diverse structure and functioning of the plant microbiome with respect to the following: (i) the high interplay of bacteria, archaea, fungi, and protists; (ii) the high specificity even at cultivar level; (iii) the vertical transmission of core microbiomes; (iv) the extraordinary function of endophytes; and (v) several unexpected functions and metabolic interactions. The plant microbiome should be recognized as an additional factor in experimental botany and breeding strategies.}, }
@article {pmid26539166, year = {2015}, author = {Kuang, W and Li, J and Zhang, S and Long, L}, title = {Diversity and distribution of Actinobacteria associated with reef coral Porites lutea.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1094}, doi = {10.3389/fmicb.2015.01094}, pmid = {26539166}, issn = {1664-302X}, abstract = {Actinobacteria is a ubiquitous major group in coral holobiont. The diversity and spatial and temporal distribution of actinobacteria have been rarely documented. In this study, diversity of actinobacteria associated with mucus, tissue and skeleton of Porites lutea and in the surrounding seawater were examined every 3 months for 1 year on Luhuitou fringing reef. The population structures of the P. lutea-associated actinobacteria were analyzed using phylogenetic analysis of 16S rRNA gene clone libraries, which demonstrated highly diverse actinobacteria profiles in P. lutea. A total of 25 described families and 10 unnamed families were determined in the populations, and 12 genera were firstly detected in corals. The Actinobacteria diversity was significantly different between the P. lutea and the surrounding seawater. Only 10 OTUs were shared by the seawater and coral samples. Redundancy and hierarchical cluster analyses were performed to analyze the correlation between the variations of actinobacteria population within the divergent compartments of P. lutea, seasonal changes, and environmental factors. The actinobacteria communities in the same coral compartment tended to cluster together. Even so, an extremely small fraction of OTUs was common in all three P. lutea compartments. Analysis of the relationship between actinobacteria assemblages and the environmental parameters showed that several genera were closely related to specific environmental factors. This study highlights that coral-associated actinobacteria populations are highly diverse, and spatially structured within P. lutea, and they are distinct from which in the ambient seawater.}, }
@article {pmid26536917, year = {2015}, author = {Zhang, Y and Ling, J and Yang, Q and Wen, C and Yan, Q and Sun, H and Van Nostrand, JD and Shi, Z and Zhou, J and Dong, J}, title = {The functional gene composition and metabolic potential of coral-associated microbial communities.}, journal = {Scientific reports}, volume = {5}, number = {}, pages = {16191}, doi = {10.1038/srep16191}, pmid = {26536917}, issn = {2045-2322}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/*genetics/*metabolism ; Carbon/metabolism ; Ecosystem ; Genetic Variation/genetics ; Homeostasis/genetics ; Nitrogen/metabolism ; Phosphorus/metabolism ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sulfur/metabolism ; }, abstract = {The phylogenetic diversity of coral-associated microbes has been extensively examined, but some contention remains regarding whether coral-associated microbial communities are species-specific or site-specific. It is suggested that corals may associate with microbes in terms of function, although little is known about the differences in coral-associated microbial functional gene composition and metabolic potential among coral species. Here, 16S rRNA Illumina sequencing and functional gene array (GeoChip 5.0) were used to assess coral-associated microbial communities. Our results indicate that both host species and environmental variables significantly correlate with shifts in the microbial community structure and functional potential. Functional genes related to key biogeochemical cycles including carbon, nitrogen, sulfur and phosphorus cycling, metal homeostasis, organic remediation, antibiotic resistance and secondary metabolism were shown to significantly vary between and among the four study corals (Galaxea astreata, Porites lutea, Porites andrewsi and Pavona decussata). Genes specific for anammox were also detected for the first time in the coral holobiont and positively correlated with ammonium. This study reveals that variability in the functional potential of coral-associated microbial communities is largely driven by changes in environmental factors and further demonstrates the importance of linking environmental parameters with genomic data in complex environmental systems.}, }
@article {pmid26510159, year = {2015}, author = {Kaniewska, P and Chan, CK and Kline, D and Ling, EY and Rosic, N and Edwards, D and Hoegh-Guldberg, O and Dove, S}, title = {Transcriptomic Changes in Coral Holobionts Provide Insights into Physiological Challenges of Future Climate and Ocean Change.}, journal = {PloS one}, volume = {10}, number = {10}, pages = {e0139223}, doi = {10.1371/journal.pone.0139223}, pmid = {26510159}, issn = {1932-6203}, mesh = {Analysis of Variance ; Animals ; Anthozoa/*genetics/*physiology ; Carbon Dioxide/analysis ; *Climate Change ; Gene Expression Profiling ; Gene Ontology ; *Oceans and Seas ; Protein Binding ; Protein Interaction Maps ; Seawater ; Temperature ; Transcriptome/*genetics ; }, abstract = {Tropical reef-building coral stress levels will intensify with the predicted rising atmospheric CO2 resulting in ocean temperature and acidification increase. Most studies to date have focused on the destabilization of coral-dinoflagellate symbioses due to warming oceans, or declining calcification due to ocean acidification. In our study, pH and temperature conditions consistent with the end-of-century scenarios of the Intergovernmental Panel on Climate Change (IPCC) caused major changes in photosynthesis and respiration, in addition to decreased calcification rates in the coral Acropora millepora. Population density of symbiotic dinoflagellates (Symbiodinium) under high levels of ocean acidification and temperature (Representative Concentration Pathway, RCP8.5) decreased to half of that found under present day conditions, with photosynthetic and respiratory rates also being reduced by 40%. These physiological changes were accompanied by evidence for gene regulation of calcium and bicarbonate transporters along with components of the organic matrix. Metatranscriptomic RNA-Seq data analyses showed an overall down regulation of metabolic transcripts, and an increased abundance of transcripts involved in circadian clock control, controlling the damage of oxidative stress, calcium signaling/homeostasis, cytoskeletal interactions, transcription regulation, DNA repair, Wnt signaling and apoptosis/immunity/ toxins. We suggest that increased maintenance costs under ocean acidification and warming, and diversion of cellular ATP to pH homeostasis, oxidative stress response, UPR and DNA repair, along with metabolic suppression, may underpin why Acroporid species tend not to thrive under future environmental stress. Our study highlights the potential increased energy demand when the coral holobiont is exposed to high levels of ocean warming and acidification.}, }
@article {pmid26483769, year = {2015}, author = {Moreira, AP and Meirelles, PM and Santos, Ede O and Amado-Filho, GM and Francini-Filho, RB and Thompson, CC and Thompson, FL}, title = {Turbulence-driven shifts in holobionts and planktonic microbial assemblages in St. Peter and St. Paul Archipelago, Mid-Atlantic Ridge, Brazil.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {1038}, doi = {10.3389/fmicb.2015.01038}, pmid = {26483769}, issn = {1664-302X}, abstract = {The aim of this study was to investigate the planktonic and the holobiont Madracis decactis (Scleractinia) microbial diversity along a turbulence-driven upwelling event, in the world's most isolated tropical island, St Peter and St Paul Archipelago (SPSPA, Brazil). Twenty one metagenomes were obtained for seawater (N = 12), healthy and bleached holobionts (N = 9) before, during and after the episode of high seawater turbulence and upwelling. Microbial assemblages differed between low turbulence-low nutrient (LLR) and high-turbulence-high nutrient (HHR) regimes in seawater. During LLR there was a balance between autotrophy and heterotrophy in the bacterioplankton and the ratio cyanobacteria:heterotrophs ~1 (C:H). Prochlorales, unclassified Alphaproteobacteria and Euryarchaeota were the dominant bacteria and archaea, respectively. Basic metabolisms and cyanobacterial phages characterized the LLR. During HHR C:H < < 0.05 and Gammaproteobacteria approximated 50% of the most abundant organisms in seawater. Alteromonadales, Oceanospirillales, and Thaumarchaeota were the dominant bacteria and archaea. Prevailing metabolisms were related to membrane transport, virulence, disease, and defense. Phages targeting heterotrophs and virulence factor genes characterized HHR. Shifts were also observed in coral microbiomes, according to both annotation-indepent and -dependent methods. HHR bleached corals metagenomes were the most dissimilar and could be distinguished by their di- and tetranucleotides frequencies, Iron Acquision metabolism and virulence genes, such as V. cholerae-related virulence factors. The healthy coral holobiont was shown to be less sensitive to transient seawater-related perturbations than the diseased animals. A conceptual model for the turbulence-induced shifts is put forward.}, }
@article {pmid26478771, year = {2015}, author = {Hunt, T}, title = {The Microcosm within: An interview with William B. Miller, Jr., on the Extended Hologenome theory of evolution.}, journal = {Communicative &amp; integrative biology}, volume = {8}, number = {3}, pages = {e1000711}, doi = {10.1080/19420889.2014.1000711}, pmid = {26478771}, issn = {1942-0889}, abstract = {There is a singular unifying reality underlying every biologic interaction on our planet. In immunology, that which does not kill you makes you different. -William B. Miller, Jr. We are experiencing a revolution in our understanding of inner space on a par with our exponentially increasing understanding of outer space. In biology, we are learning that the genetic and epigenetic complexity within organisms is far deeper than suspected. This is a key theme in William B. Miller Jr.'s book, The Microcosm Within: Evolution and Extinction in the Hologenome. We are learning also that a focus on the human genome alone is misleading when it comes to who we really are as biological entities, and in terms of how we and other creatures have evolved. Rather than being defined by the human genome alone, we are instead defined by the &quot;hologenome,&quot; the sum of the human genome and the far larger genetic endowment of the microbiome and symbiotic communities that reside within and around us. Miller is a medical doctor previously in private practice in Pennsylvania and Phoenix, Arizona. This book is his first foray into evolutionary theory. His book could have been titled &quot;The Origin of Variation&quot; because this is his primary focus. He accepts that natural selection plays a role in evolution, but he demotes this mechanism to a less important role than the Modern Synthesis suggests. His main gripe, however, concerns random variation. He argues that random variation is unable to explain the origin and evolution of biological forms that we see in the world around us and in the historical record. Miller suggests that, rather than random variation as the engine of novelty, there is a creative impulse at the heart of cellular life, and even at the level of the genetic aggregate, that generates novelty on a regular basis. I probe this assertion in the interview below. He also highlights the strong role of &quot;exogenous genetic assault&quot; in variation and in his immunological model of evolution.}, }
@article {pmid26451236, year = {2015}, author = {Meyer, JL and Dillard, BA and Rodgers, JM and Ritchie, KB and Paul, VJ and Teplitski, M}, title = {Draft genome sequence of Halomonas meridiana R1t3 isolated from the surface microbiota of the Caribbean Elkhorn coral Acropora palmata.}, journal = {Standards in genomic sciences}, volume = {10}, number = {}, pages = {75}, doi = {10.1186/s40793-015-0069-y}, pmid = {26451236}, issn = {1944-3277}, abstract = {Members of the gammaproteobacterial genus Halomonas are common in marine environments. Halomonas and other members of the Oceanospirillales have recently been identified as prominent members of the surface microbiota of reef-building corals. Halomonas meridiana strain R1t3 was isolated from the surface mucus layer of the scleractinian coral Acropora palmata in 2005 from the Florida Keys. This strain was chosen for genome sequencing to provide insight into the role of commensal heterotrophic bacteria in the coral holobiont. The draft genome consists of 290 scaffolds, totaling 3.5 Mbp in length and contains 3397 protein-coding genes.}, }
@article {pmid26442023, year = {2015}, author = {Smith, DL and Subramanian, S and Lamont, JR and Bywater-Ekegärd, M}, title = {Signaling in the phytomicrobiome: breadth and potential.}, journal = {Frontiers in plant science}, volume = {6}, number = {}, pages = {709}, doi = {10.3389/fpls.2015.00709}, pmid = {26442023}, issn = {1664-462X}, abstract = {Higher plants have evolved intimate, complex, subtle, and relatively constant relationships with a suite of microbes, the phytomicrobiome. Over the last few decades we have learned that plants and microbes can use molecular signals to communicate. This is well-established for the legume-rhizobia nitrogen-fixing symbiosis, and reasonably elucidated for mycorrhizal associations. Bacteria within the phytomircobiome communicate among themselves through quorum sensing and other mechanisms. Plants also detect materials produced by potential pathogens and activate pathogen-response systems. This intercommunication dictates aspects of plant development, architecture, and productivity. Understanding this signaling via biochemical, genomics, proteomics, and metabolomic studies has added valuable knowledge regarding development of effective, low-cost, eco-friendly crop inputs that reduce fossil fuel intense inputs. This knowledge underpins phytomicrobiome engineering: manipulating the beneficial consortia that manufacture signals/products that improve the ability of the plant-phytomicrobiome community to deal with various soil and climatic conditions, leading to enhanced overall crop plant productivity.}, }
@article {pmid26441903, year = {2015}, author = {Minard, G and Tran, FH and Van, VT and Goubert, C and Bellet, C and Lambert, G and Kim, KL and Thuy, TH and Mavingui, P and Valiente Moro, C}, title = {French invasive Asian tiger mosquito populations harbor reduced bacterial microbiota and genetic diversity compared to Vietnamese autochthonous relatives.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {970}, doi = {10.3389/fmicb.2015.00970}, pmid = {26441903}, issn = {1664-302X}, abstract = {The Asian tiger mosquito Aedes albopictus is one of the most significant pathogen vectors of the twenty-first century. Originating from Asia, it has invaded a wide range of eco-climatic regions worldwide. The insect-associated microbiota is now recognized to play a significant role in host biology. While genetic diversity bottlenecks are known to result from biological invasions, the resulting shifts in host-associated microbiota diversity has not been thoroughly investigated. To address this subject, we compared four autochthonous Ae. albopictus populations in Vietnam, the native area of Ae. albopictus, and three populations recently introduced to Metropolitan France, with the aim of documenting whether these populations display differences in host genotype and bacterial microbiota. Population-level genetic diversity (microsatellite markers and COI haplotype) and bacterial diversity (16S rDNA metabarcoding) were compared between field-caught mosquitoes. Bacterial microbiota from the whole insect bodies were largely dominated by Wolbachia pipientis. Targeted analysis of the gut microbiota revealed a greater bacterial diversity in which a fraction was common between French and Vietnamese populations. The genus Dysgonomonas was the most prevalent and abundant across all studied populations. Overall genetic diversities of both hosts and bacterial microbiota were significantly reduced in recently established populations of France compared to the autochthonous populations of Vietnam. These results open up many important avenues of investigation in order to link the process of geographical invasion to shifts in commensal and symbiotic microbiome communities, as such shifts may have dramatic impacts on the biology and/or vector competence of invading hematophagous insects.}, }
@article {pmid26414414, year = {2015}, author = {Blackall, LL and Wilson, B and van Oppen, MJ}, title = {Coral-the world's most diverse symbiotic ecosystem.}, journal = {Molecular ecology}, volume = {24}, number = {21}, pages = {5330-5347}, doi = {10.1111/mec.13400}, pmid = {26414414}, issn = {1365-294X}, mesh = {Animals ; Anthozoa/genetics/*microbiology ; Archaea/classification ; Bacteria/*classification ; Biodiversity ; *Coral Reefs ; DNA, Bacterial/genetics ; DNA, Ribosomal Spacer/genetics ; Dinoflagellida/*classification ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; *Symbiosis ; }, abstract = {Zooxanthellate corals (i.e. those harbouring Symbiodinium) are the main builders of the world's shallow-water marine coral reefs. They represent intimate diverse symbioses between coral animals, single-celled photosynthetic dinoflagellates (Symbiodinium spp.), other microscopic eukaryotes, prokaryotes and viruses. Crabs and other crustaceans, worms, sponges, bivalves and hydrozoans, fishes, sea urchins, octopuses and sea stars are itinerant members of these 'rainforests of the sea'. This review focuses on the biodiversity of scleractinian coral animals and their best studied microscopic epi- and endosymbionts. In relation to coral-associated species diversity, Symbiodinium internal transcribed spacer region sequence types tally 10(2) -10(3) or up to ~15 different operational taxonomic units (OTUs, or putative species at the 97% sequence identity level; this cut-off was chosen based on intragenomic sequence diversity observed in monoclonal cultures) and prokaryotes (mostly bacterial) total 10(2) -10(4) OTUs. We analysed all publically accessible 16S rRNA gene sequence data and found Gammaproteobacteria were extremely abundant, followed by Alphaproteobacteria. Notably, Archaea were poorly represented and 'unassigned OTUs' were abundant in data generated by high-throughput DNA sequencing studies of corals. We outline and compare model systems that could be used in future studies of the coral holobiont. In our future directions, we recommend a global coral sampling effort including substantial attention being paid to method of coral tissue acquisition, which compartments (mucus, tissue, skeleton) to explore, broadening the holobiont members considered and linking biodiversity with functional investigations.}, }
@article {pmid26388838, year = {2015}, author = {Har, JY and Helbig, T and Lim, JH and Fernando, SC and Reitzel, AM and Penn, K and Thompson, JR}, title = {Microbial diversity and activity in the Nematostella vectensis holobiont: insights from 16S rRNA gene sequencing, isolate genomes, and a pilot-scale survey of gene expression.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {818}, doi = {10.3389/fmicb.2015.00818}, pmid = {26388838}, issn = {1664-302X}, support = {P30 ES002109/ES/NIEHS NIH HHS/United States ; }, abstract = {We have characterized the molecular and genomic diversity of the microbiota of the starlet sea anemone Nematostella vectensis, a cnidarian model for comparative developmental and functional biology and a year-round inhabitant of temperate salt marshes. Molecular phylogenetic analysis of 16S rRNA gene clone libraries revealed four ribotypes associated with N. vectensis at multiple locations and times. These associates include two novel ribotypes within the ε-Proteobacterial order Campylobacterales and the Spirochetes, respectively, each sharing <85% identity with cultivated strains, and two γ-Proteobacterial ribotypes sharing >99% 16S rRNA identity with Endozoicomonas elysicola and Pseudomonas oleovorans, respectively. Species-specific PCR revealed that these populations persisted in N. vectensis asexually propagated under laboratory conditions. cDNA indicated expression of the Campylobacterales and Endozoicomonas 16S rRNA in anemones from Sippewissett Marsh, MA. A collection of bacteria from laboratory raised N. vectensis was dominated by isolates from P. oleovorans and Rhizobium radiobacter. Isolates from field-collected anemones revealed an association with Limnobacter and Stappia isolates. Genomic DNA sequencing was carried out on 10 cultured bacterial isolates representing field- and laboratory-associates, i.e., Limnobacter spp., Stappia spp., P. oleovorans and R. radiobacter. Genomes contained multiple genes identified as virulence (host-association) factors while S. stellulata and L. thiooxidans genomes revealed pathways for mixotrophic sulfur oxidation. A pilot metatranscriptome of laboratory-raised N. vectensis was compared to the isolate genomes and indicated expression of ORFs from L. thiooxidans with predicted functions of motility, nutrient scavenging (Fe and P), polyhydroxyalkanoate synthesis for carbon storage, and selective permeability (porins). We hypothesize that such activities may mediate acclimation and persistence of bacteria in a N. vectensis holobiont defined by both internal and external gradients of chemicals and nutrients in a dynamic coastal habitat.}, }
@article {pmid26311127, year = {2016}, author = {Meisterhans, G and Raymond, N and Girault, E and Lambert, C and Bourrasseau, L and de Montaudouin, X and Garabetian, F and Jude-Lemeilleur, F}, title = {Structure of Manila Clam (Ruditapes philippinarum) Microbiota at the Organ Scale in Contrasting Sets of Individuals.}, journal = {Microbial ecology}, volume = {71}, number = {1}, pages = {194-206}, doi = {10.1007/s00248-015-0662-z}, pmid = {26311127}, issn = {1432-184X}, mesh = {Animal Structures/*microbiology ; Animals ; Bacteria/classification/genetics/*isolation &amp; purification ; Bivalvia/*microbiology ; *Microbiota ; Shellfish/*microbiology ; }, abstract = {Marine invertebrate microbiota has a key function in host physiology and health. To date, knowledge about bivalve microbiota is poorly documented except public health concerns. This study used a molecular approach to characterize the microbiota associated with the bivalve Manila clam (Ruditapes philippinarum) by determining (1) the difference among organs either or not under the influence of host habitat, (2) small-scale variability of microbiota, and (3) the experimental response of the Manila clam microbiota submitted to different lateral transmissions. These questions were investigated by sampling two groups of individuals living in contrasting habitats and carrying out a transplant experiment. Manila clam microbiota (i.e., bacterial community structure) was determined at organ-scale (gills, gut, and a pool of remaining tissues) by capillary electrophoresis DNA fingerprinting (CE fingerprinting). The Manila clam microbiota structure differed among organs indicating a selection of Manila clam microbiota at organ scale. Habitat strongly influenced gill and gut microbiota. In contrast, microbiota associated with remaining tissues was similar between group individuals suggesting that these communities are mostly autochthonous, i.e., Manila clam specific. Transplant experiment showed that improving living condition did not induce any change in microbiota associated with remaining tissues. In contrast, the reduction in individual habitat quality led to individuals in declining health as strongly suggested by the increase in phagocytosis activity and decrease in condition index together with the change in internal organ microbiota. This study provides a first description of the Manila clam holobiont which can withstand disturbance and respond opportunistically to improved environmental conditions.}, }
@article {pmid26300848, year = {2015}, author = {Voss, JD and Leon, JC and Dhurandhar, NV and Robb, FT}, title = {Pawnobiome: manipulation of the hologenome within one host generation and beyond.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {697}, doi = {10.3389/fmicb.2015.00697}, pmid = {26300848}, issn = {1664-302X}, }
@article {pmid26293603, year = {2016}, author = {Nogales, A and Nobre, T and Valadas, V and Ragonezi, C and Döring, M and Polidoros, A and Arnholdt-Schmitt, B}, title = {Can functional hologenomics aid tackling current challenges in plant breeding?.}, journal = {Briefings in functional genomics}, volume = {15}, number = {4}, pages = {288-297}, doi = {10.1093/bfgp/elv030}, pmid = {26293603}, issn = {2041-2657}, mesh = {Genomics/*methods ; Phenotype ; *Plant Breeding ; Plants/*genetics ; *Quantitative Trait Loci ; }, abstract = {Molecular plant breeding usually overlooks the genetic variability that arises from the association of plants with endophytic microorganisms, when looking at agronomic interesting target traits. This source of variability can have crucial effects on the functionality of the organism considered as a whole (the holobiont), and therefore can be selectable in breeding programs. However, seeing the holobiont as a unit for selection and improvement in breeding programs requires novel approaches for genotyping and phenotyping. These should not focus just at the plant level, but also include the associated endophytes and their functional effects on the plant, to make effective desirable trait screenings. The present review intends to draw attention to a new research field on functional hologenomics that if associated with adequate phenotyping tools could greatly increase the efficiency of breeding programs.}, }
@article {pmid26291447, year = {2015}, author = {Krediet, CJ and DeNofrio, JC and Caruso, C and Burriesci, MS and Cella, K and Pringle, JR}, title = {Rapid, Precise, and Accurate Counts of Symbiodinium Cells Using the Guava Flow Cytometer, and a Comparison to Other Methods.}, journal = {PloS one}, volume = {10}, number = {8}, pages = {e0135725}, doi = {10.1371/journal.pone.0135725}, pmid = {26291447}, issn = {1932-6203}, mesh = {Animals ; Cnidaria/cytology ; Dinoflagellida/cytology ; Flow Cytometry/*methods ; Symbiosis/physiology ; }, abstract = {In studies of both the establishment and breakdown of cnidarian-dinoflagellate symbiosis, it is often necessary to determine the number of Symbiodinium cells relative to the quantity of host tissue. Ideally, the methods used should be rapid, precise, and accurate. In this study, we systematically evaluated methods for sample preparation and storage and the counting of algal cells using the hemocytometer, a custom image-analysis program for automated counting of the fluorescent algal cells, the Coulter Counter, or the Millipore Guava flow-cytometer. We found that although other methods may have value in particular applications, for most purposes, the Guava flow cytometer provided by far the best combination of precision, accuracy, and efficient use of investigator time (due to the instrument's automated sample handling), while also allowing counts of algal numbers over a wide range and in small volumes of tissue homogenate. We also found that either of two assays of total homogenate protein provided a precise and seemingly accurate basis for normalization of algal counts to the total amount of holobiont tissue.}, }
@article {pmid26284777, year = {2015}, author = {Bordenstein, SR and Theis, KR}, title = {Host Biology in Light of the Microbiome: Ten Principles of Holobionts and Hologenomes.}, journal = {PLoS biology}, volume = {13}, number = {8}, pages = {e1002226}, doi = {10.1371/journal.pbio.1002226}, pmid = {26284777}, issn = {1545-7885}, support = {P30 DK058404/DK/NIDDK NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; Humans ; *Metagenome ; Microbiota/*genetics ; Mutation ; Plants/genetics ; Selection, Genetic ; Symbiosis/*genetics ; }, abstract = {Groundbreaking research on the universality and diversity of microorganisms is now challenging the life sciences to upgrade fundamental theories that once seemed untouchable. To fully appreciate the change that the field is now undergoing, one has to place the epochs and foundational principles of Darwin, Mendel, and the modern synthesis in light of the current advances that are enabling a new vision for the central importance of microbiology. Animals and plants are no longer heralded as autonomous entities but rather as biomolecular networks composed of the host plus its associated microbes, i.e., &quot;holobionts.&quot; As such, their collective genomes forge a &quot;hologenome,&quot; and models of animal and plant biology that do not account for these intergenomic associations are incomplete. Here, we integrate these concepts into historical and contemporary visions of biology and summarize a predictive and refutable framework for their evaluation. Specifically, we present ten principles that clarify and append what these concepts are and are not, explain how they both support and extend existing theory in the life sciences, and discuss their potential ramifications for the multifaceted approaches of zoology and botany. We anticipate that the conceptual and evidence-based foundation provided in this essay will serve as a roadmap for hypothesis-driven, experimentally validated research on holobionts and their hologenomes, thereby catalyzing the continued fusion of biology's subdisciplines. At a time when symbiotic microbes are recognized as fundamental to all aspects of animal and plant biology, the holobiont and hologenome concepts afford a holistic view of biological complexity that is consistent with the generally reductionist approaches of biology.}, }
@article {pmid29587997, year = {2015}, author = {Schwarz, RS and Huang, Q and Evans, JD}, title = {Hologenome theory and the honey bee pathosphere.}, journal = {Current opinion in insect science}, volume = {10}, number = {}, pages = {1-7}, doi = {10.1016/j.cois.2015.04.006}, pmid = {29587997}, issn = {2214-5753}, abstract = {Recent research has provided improved genome-level views of diversity across global honey bee populations, the gut microbiota residing within them, and the expanding pathosphere challenging honey bees. Different combinations of bee/microbiota/pathosphere genome complexes may explain regional variation in apiculture productivity and mortality. To understand this, we must consider management and research approaches in light of a hologenome paradigm: that honey bee fitness is determined by the composite bee and microbiota genomes. Only by considering the hologenome can we truly interpret and address impacts from the pathosphere, pesticides, toxins, nutrition, climate and other stressors affecting bee health.}, }
@article {pmid26177948, year = {2015}, author = {Kramer, P and Bressan, P}, title = {Humans as Superorganisms: How Microbes, Viruses, Imprinted Genes, and Other Selfish Entities Shape Our Behavior.}, journal = {Perspectives on psychological science : a journal of the Association for Psychological Science}, volume = {10}, number = {4}, pages = {464-481}, doi = {10.1177/1745691615583131}, pmid = {26177948}, issn = {1745-6924}, mesh = {Animals ; Behavior/*physiology ; Brain/*microbiology/parasitology/*virology ; *Genomic Imprinting ; Humans ; *Microbiota ; *Viruses ; }, abstract = {Psychologists and psychiatrists tend to be little aware that (a) microbes in our brains and guts are capable of altering our behavior; (b) viral DNA that was incorporated into our DNA millions of years ago is implicated in mental disorders; (c) many of us carry the cells of another human in our brains; and (d) under the regulation of viruslike elements, the paternally inherited and maternally inherited copies of some genes compete for domination in the offspring, on whom they have opposite physical and behavioral effects. This article provides a broad overview, aimed at a wide readership, of the consequences of our coexistence with these selfish entities. The overarching message is that we are not unitary individuals but superorganisms, built out of both human and nonhuman elements; it is their interaction that determines who we are.}, }
@article {pmid26099965, year = {2015}, author = {Aires, T and Moalic, Y and Serrao, EA and Arnaud-Haond, S}, title = {Hologenome theory supported by cooccurrence networks of species-specific bacterial communities in siphonous algae (Caulerpa).}, journal = {FEMS microbiology ecology}, volume = {91}, number = {7}, pages = {}, doi = {10.1093/femsec/fiv067}, pmid = {26099965}, issn = {1574-6941}, mesh = {Animals ; Anthozoa ; Bacteria/*genetics ; Biodiversity ; Caulerpa/genetics/*microbiology ; Endophytes/*genetics ; Mediterranean Sea ; Microbial Consortia/*genetics ; Plants ; Porifera/microbiology ; RNA, Ribosomal, 16S/genetics ; Species Specificity ; }, abstract = {The siphonous algae of the Caulerpa genus harbor internal microbial communities hypothesized to play important roles in development, defense and metabolic activities of the host. Here, we characterize the endophytic bacterial community of four Caulerpa taxa in the Mediterranean Sea, through 16S rRNA amplicon sequencing. Results reveal a striking alpha diversity of the bacterial communities, similar to levels found in sponges and coral holobionts. These comprise (1) a very small core community shared across all hosts (< 1% of the total community), (2) a variable portion (ca. 25%) shared by some Caulerpa taxa but not by all, which might represent environmentally acquired bacteria and (3) a large (>70%) species-specific fraction of the community, forming very specific clusters revealed by modularity in networks of cooccurrence, even in areas where distinct Caulerpa taxa occurred in sympatry. Indirect inferences based on sequence homology suggest that these communities may play an important role in the metabolism of their host, in particular on their ability to grow on anoxic sediment. These findings support the hologenome theory and the need for a holistic framework in ecological and evolutionary studies of these holobionts that frequently become invasive.}, }
@article {pmid26097896, year = {2015}, author = {Zhao, Y and Lukiw, WJ}, title = {Microbiome-generated amyloid and potential impact on amyloidogenesis in Alzheimer's disease (AD).}, journal = {Journal of nature and science}, volume = {1}, number = {7}, pages = {}, pmid = {26097896}, issn = {2377-2700}, support = {R01 AG018031/AG/NIA NIH HHS/United States ; R01 AG038834/AG/NIA NIH HHS/United States ; R01 EY006311/EY/NEI NIH HHS/United States ; }, abstract = {According to the 'amyloid cascade hypothesis of Alzheimer's disease' first proposed about 16 years ago, the accumulation of Aβ peptides in the human central nervous system (CNS) is the primary influence driving Alzheimer's disease (AD) pathogenesis, and Aβ peptide accretion is the result of an imbalance between Aβ peptide production and clearance. In the last 18 months multiple laboratories have reported two particularly important observations: (i) that because the microbes of the human microbiome naturally secrete large amounts of amyloid, lipopolysaccharides (LPS) and other related pro-inflammatory pathogenic signals, these may contribute to both the systemic and CNS amyloid burden in aging humans; and (ii) that the clearance of Aβ peptides appears to be intrinsically impaired by deficits in the microglial plasma-membrane enriched triggering receptor expressed in microglial/myeloid-2 cells (TREM2). This brief general commentary-perspective paper: (i) will highlight some of these very recent findings on microbiome-secreted amyloids and LPS and the potential contribution of these microbial-derived pro-inflammatory and neurotoxic exudates to age-related inflammatory and AD-type neurodegeneration in the host; and (ii) will discuss the contribution of a defective microglial-based TREM2 transmembrane sensor-receptor system to amyloidogenesis in AD that is in contrast to the normal, homeostatic clearance of Aβ peptides from the human CNS.}, }
@article {pmid26064625, year = {2015}, author = {Pinzón, JH and Kamel, B and Burge, CA and Harvell, CD and Medina, M and Weil, E and Mydlarz, LD}, title = {Whole transcriptome analysis reveals changes in expression of immune-related genes during and after bleaching in a reef-building coral.}, journal = {Royal Society open science}, volume = {2}, number = {4}, pages = {140214}, doi = {10.1098/rsos.140214}, pmid = {26064625}, issn = {2054-5703}, abstract = {Climate change is negatively affecting the stability of natural ecosystems, especially coral reefs. The dissociation of the symbiosis between reef-building corals and their algal symbiont, or coral bleaching, has been linked to increased sea surface temperatures. Coral bleaching has significant impacts on corals, including an increase in disease outbreaks that can permanently change the entire reef ecosystem. Yet, little is known about the impacts of coral bleaching on the coral immune system. In this study, whole transcriptome analysis of the coral holobiont and each of the associate components (i.e. coral host, algal symbiont and other associated microorganisms) was used to determine changes in gene expression in corals affected by a natural bleaching event as well as during the recovery phase. The main findings include evidence that the coral holobiont and the coral host have different responses to bleaching, and the host immune system appears suppressed even a year after a bleaching event. These results support the hypothesis that coral bleaching changes the expression of innate immune genes of corals, and these effects can last even after recovery of symbiont populations. Research on the role of immunity on coral's resistance to stressors can help make informed predictions on the future of corals and coral reefs.}, }
@article {pmid26047662, year = {2016}, author = {Stilling, RM and Dinan, TG and Cryan, JF}, title = {The brain's Geppetto-microbes as puppeteers of neural function and behaviour?.}, journal = {Journal of neurovirology}, volume = {22}, number = {1}, pages = {14-21}, doi = {10.1007/s13365-015-0355-x}, pmid = {26047662}, issn = {1538-2443}, mesh = {Animals ; *Behavior ; Behavior, Animal ; Biological Evolution ; Brain/*microbiology/parasitology/physiopathology/virology ; Diet ; Feeding Behavior ; Gastrointestinal Microbiome/*physiology ; Gastrointestinal Tract/*microbiology/parasitology/physiopathology/virology ; *Host-Pathogen Interactions ; Humans ; Symbiosis/physiology ; }, abstract = {Research on the microbiome and its interaction with various host organs, including the brain, is increasingly gaining momentum. With more evidence establishing a comprehensive microbiota-gut-brain axis, questions have been raised as to the extent to which microbes influence brain physiology and behaviour. In parallel, there is a growing literature showing active behavioural manipulation in favour of the microbe for certain parasites. However, it seems unclear where the hidden majority of microbes are localised on the parasitism-mutualism spectrum. A long evolutionary history intimately connects host and microbiota, which complicates this classification. In this conceptual minireview, we discuss current hypotheses on host-microbe interaction and argue that novel experimental approaches and theoretical concepts, such as the hologenome theory, are necessary to incorporate transgenerational epigenetic inheritance of the microbiome into evolutionary theories.}, }
@article {pmid26039986, year = {2015}, author = {Wilson, AC and Duncan, RP}, title = {Signatures of host/symbiont genome coevolution in insect nutritional endosymbioses.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {112}, number = {33}, pages = {10255-10261}, doi = {10.1073/pnas.1423305112}, pmid = {26039986}, issn = {1091-6490}, mesh = {Amino Acids/chemistry ; Amino Acids, Branched-Chain/chemistry ; Animals ; Bacteria/genetics ; Buchnera/genetics ; Cell Lineage ; Cytoplasm/metabolism ; *Evolution, Molecular ; Gene Expression Profiling ; Gene Transfer, Horizontal ; Genome ; Genome, Bacterial ; Hemiptera/*genetics/*microbiology ; Pantothenic Acid/chemistry ; *Symbiosis ; }, abstract = {The role of symbiosis in bacterial symbiont genome evolution is well understood, yet the ways that symbiosis shapes host genomes or more particularly, host/symbiont genome coevolution in the holobiont is only now being revealed. Here, we identify three coevolutionary signatures that characterize holobiont genomes. The first signature, host/symbiont collaboration, arises when completion of essential pathways requires host/endosymbiont genome complementarity. Metabolic collaboration has evolved numerous times in the pathways of amino acid and vitamin biosynthesis. Here, we highlight collaboration in branched-chain amino acid and pantothenate (vitamin B5) biosynthesis. The second coevolutionary signature is acquisition, referring to the observation that holobiont genomes acquire novel genetic material through various means, including gene duplication, lateral gene transfer from bacteria that are not their current obligate symbionts, and full or partial endosymbiont replacement. The third signature, constraint, introduces the idea that holobiont genome evolution is constrained by the processes governing symbiont genome evolution. In addition, we propose that collaboration is constrained by the expression profile of the cell lineage from which endosymbiont-containing host cells, called bacteriocytes, are derived. In particular, we propose that such differences in bacteriocyte cell lineage may explain differences in patterns of host/endosymbiont metabolic collaboration between the sap-feeding suborders Sternorrhyncha and Auchenorrhynca. Finally, we review recent studies at the frontier of symbiosis research that are applying functional genomic approaches to characterization of the developmental and cellular mechanisms of host/endosymbiont integration, work that heralds a new era in symbiosis research.}, }
@article {pmid26028424, year = {2015}, author = {Price, DR and Wilson, AC and Luetje, CW}, title = {Proton-dependent glutamine uptake by aphid bacteriocyte amino acid transporter ApGLNT1.}, journal = {Biochimica et biophysica acta}, volume = {1848}, number = {10 Pt A}, pages = {2085-2091}, doi = {10.1016/j.bbamem.2015.05.019}, pmid = {26028424}, issn = {0006-3002}, support = {DC011091/DC/NIDCD NIH HHS/United States ; }, mesh = {Animals ; Aphids/*microbiology ; Buchnera/*metabolism ; Cells, Cultured ; Glutamine/*pharmacokinetics ; Ion Channel Gating/*physiology ; Membrane Potentials/*physiology ; Oocytes/*physiology ; Protons ; Xenopus laevis ; }, abstract = {Aphids house large populations of the gammaproteobacterial symbiont Buchnera aphidicola in specialized bacteriocyte cells. The combined biosynthetic capability of the holobiont (Acyrthosiphon pisum and Buchnera) is sufficient for biosynthesis of all twenty protein coding amino acids, including amino acids that animals alone cannot synthesize; and that are present at low concentrations in A. pisum's plant phloem sap diet. Collaborative holobiont amino acid biosynthesis depends on glutamine import into bacteriocytes, which serves as a nitrogen-rich amino donor for biosynthesis of other amino acids. Recently, we characterized A. pisum glutamine transporter 1 (ApGLNT1), a member of the amino acid/auxin permease family, as the dominant bacteriocyte plasma membrane glutamine transporter. Here we show ApGLNT1 to be structurally and functionally related to mammalian proton-dependent amino acid transporters (PATs 1-4). Using functional expression in Xenopus laevis oocytes, combined with two-electrode voltage clamp electrophysiology we demonstrate that ApGLNT1 is electrogenic and that glutamine induces large inward currents. ApGLNT1 glutamine induced currents are dependent on external glutamine concentration, proton (H+) gradient across the membrane, and membrane potential. Based on these transport properties, ApGLNT1-mediated glutamine uptake into A. pisum bacteriocytes can be regulated by changes in either proton gradients across the plasma membrane or membrane potential.}, }
@article {pmid26026593, year = {2015}, author = {Dheilly, NM and Poulin, R and Thomas, F}, title = {Biological warfare: Microorganisms as drivers of host-parasite interactions.}, journal = {Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases}, volume = {34}, number = {}, pages = {251-259}, doi = {10.1016/j.meegid.2015.05.027}, pmid = {26026593}, issn = {1567-7257}, mesh = {Animals ; *Biological Warfare ; *Host-Parasite Interactions ; Humans ; Microbiota ; Parasitic Diseases/*microbiology/parasitology ; Symbiosis ; }, abstract = {Understanding parasite strategies for evasion, manipulation or exploitation of hosts is crucial for many fields, from ecology to medical sciences. Generally, research has focused on either the host response to parasitic infection, or the parasite virulence mechanisms. More recently, integrated studies of host-parasite interactions have allowed significant advances in theoretical and applied biology. However, these studies still provide a simplistic view of these as mere two-player interactions. Host and parasite are associated with a myriad of microorganisms that could benefit from the improved fitness of their partner. Illustrations of such complex multi-player interactions have emerged recently from studies performed in various taxa. In this conceptual article, we propose how these associated microorganisms may participate in the phenotypic alterations induced by parasites and hence in host-parasite interactions, from an ecological and evolutionary perspective. Host- and parasite-associated microorganisms may participate in the host-parasite interaction by interacting directly or indirectly with the other partner. As a result, parasites may develop (i) the disruptive strategy in which the parasite alters the host microbiota to its advantage, and (ii) the biological weapon strategy where the parasite-associated microorganism contributes to or modulates the parasite's virulence. Some phenotypic alterations induced by parasite may also arise from conflicts of interests between the host or parasite and its associated microorganism. For each situation, we review the literature and propose new directions for future research. Specifically, investigating the role of host- and parasite-associated microorganisms in host-parasite interactions at the individual, local and regional level will lead to a holistic understanding of how the co-evolution of the different partners influences how the other ones respond, both ecologically and evolutionary. The conceptual framework we propose here is important and relevant to understand the proximate basis of parasite strategies, to predict their evolutionary dynamics and potentially to prevent therapeutic failures.}, }
@article {pmid26020776, year = {2015}, author = {Gudenkauf, BM and Hewson, I}, title = {Metatranscriptomic Analysis of Pycnopodia helianthoides (Asteroidea) Affected by Sea Star Wasting Disease.}, journal = {PloS one}, volume = {10}, number = {5}, pages = {e0128150}, doi = {10.1371/journal.pone.0128150}, pmid = {26020776}, issn = {1932-6203}, mesh = {Animals ; *Energy Metabolism ; *Gene Expression Regulation ; Starfish/genetics/*metabolism ; *Transcriptome ; Wasting Syndrome/genetics/*metabolism/pathology/*veterinary ; }, abstract = {Sea star wasting disease (SSWD) describes a suite of symptoms reported in asteroids of the North American Pacific Coast. We performed a metatranscriptomic survey of asymptomatic and symptomatic sunflower star (Pycnopodia helianthoides) body wall tissues to understand holobiont gene expression in tissues affected by SSWD. Metatranscriptomes were highly variable between replicate libraries, and most differentially expressed genes represented either transcripts of associated microorganisms (particularly Pseudomonas and Vibrio relatives) or low-level echinoderm transcripts of unknown function. However, the pattern of annotated host functional genes reflects enhanced apoptotic and tissue degradation processes and decreased energy metabolism, while signalling of death-related proteins was greater in asymptomatic and symptomatic tissues. Our results suggest that the body wall tissues of SSWD-affected asteroids may undergo structural changes during disease progression, and that they are stimulated to undergo autocatalytic cell death processes.}, }
@article {pmid26018191, year = {2015}, author = {Roder, C and Bayer, T and Aranda, M and Kruse, M and Voolstra, CR}, title = {Microbiome structure of the fungid coral Ctenactis echinata aligns with environmental differences.}, journal = {Molecular ecology}, volume = {24}, number = {13}, pages = {3501-3511}, doi = {10.1111/mec.13251}, pmid = {26018191}, issn = {1365-294X}, mesh = {Animals ; Anthozoa/*microbiology ; Biodiversity ; Coral Reefs ; *Environment ; Indian Ocean ; *Microbiota ; RNA, Ribosomal, 16S/genetics ; Seasons ; Sequence Analysis, DNA ; Spatio-Temporal Analysis ; }, abstract = {The significance of bacteria for eukaryotic functioning is increasingly recognized. Coral reef ecosystems critically rely on the relationship between coral hosts and their intracellular photosynthetic dinoflagellates, but the role of the associated bacteria remains largely theoretical. Here, we set out to relate coral-associated bacterial communities of the fungid host species Ctenactis echinata to environmental settings (geographic location, substrate cover, summer/winter, nutrient and suspended matter concentrations) and coral host abundance. We show that bacterial diversity of C. echinata aligns with ecological differences between sites and that coral colonies sampled at the species' preferred habitats are primarily structured by one bacterial taxon (genus Endozoicomonas) representing more than 60% of all bacteria. In contrast, host microbiomes from lower populated coral habitats are less structured and more diverse. Our study demonstrates that the content and structure of the coral microbiome aligns with environmental differences and denotes habitat adequacy. Availability of a range of coral host habitats might be important for the conservation of distinct microbiome structures and diversity.}, }
@article {pmid25989369, year = {2015}, author = {Baker, DM and Freeman, CJ and Knowlton, N and Thacker, RW and Kim, K and Fogel, ML}, title = {Productivity links morphology, symbiont specificity and bleaching in the evolution of Caribbean octocoral symbioses.}, journal = {The ISME journal}, volume = {9}, number = {12}, pages = {2620-2629}, doi = {10.1038/ismej.2015.71}, pmid = {25989369}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*physiology ; Biological Evolution ; Carbon Cycle ; Caribbean Region ; Dinoflagellida/classification/genetics/isolation &amp; purification/*physiology ; Photosynthesis ; Phylogeny ; *Symbiosis ; }, abstract = {Many cnidarians host endosymbiotic dinoflagellates from the genus Symbiodinium. It is generally assumed that the symbiosis is mutualistic, where the host benefits from symbiont photosynthesis while providing protection and photosynthetic substrates. Diverse assemblages of symbiotic gorgonian octocorals can be found in hard bottom communities throughout the Caribbean. While current research has focused on the phylo- and population genetics of gorgonian symbiont types and their photo-physiology, relatively less work has focused on biogeochemical benefits conferred to the host and how these benefits vary across host species. Here we examine this symbiosis among 11 gorgonian species collected in Bocas del Toro, Panama. By coupling light and dark bottle incubations (P/R) with (13)C-bicarbonate tracers, we quantified the link between holobiont oxygen metabolism with carbon assimilation and translocation from symbiont to host. Our data show that P/R varied among species, and was correlated with colony morphology and polyp size. Sea fans and sea plumes were net autotrophs (P/R>1.5), while nine species of sea rods were net heterotrophs with most below compensation (P/R<1.0). (13)C assimilation corroborated the P/R results, and maximum δ(13)Chost values were strongly correlated with polyp size, indicating higher productivity by colonies with high polyp SA:V. A survey of gorgonian-Symbiodinium associations revealed that productive species maintain specialized, obligate symbioses and are more resistant to coral bleaching, whereas generalist and facultative associations are common among sea rods that have higher bleaching sensitivities. Overall, productivity and polyp size had strong phylogenetic signals with carbon fixation and polyp size showing evidence of trait covariance.}, }
@article {pmid25977840, year = {2015}, author = {Zhao, Y and Dua, P and Lukiw, WJ}, title = {Microbial Sources of Amyloid and Relevance to Amyloidogenesis and Alzheimer's Disease (AD).}, journal = {Journal of Alzheimer's disease &amp; Parkinsonism}, volume = {5}, number = {1}, pages = {177}, doi = {10.4172/2161-0460.1000177}, pmid = {25977840}, issn = {2161-0460}, support = {R01 EY006311/EY/NEI NIH HHS/United States ; R01 AG018031/AG/NIA NIH HHS/United States ; P50 AG016573/AG/NIA NIH HHS/United States ; R01 AG038834/AG/NIA NIH HHS/United States ; P30 GM103340/GM/NIGMS NIH HHS/United States ; }, abstract = {Since the inception of the human microbiome project (HMP) by the US National Institutes of Health (NIH) in 2007 there has been a keen resurgence in our recognition of the human microbiome and its contribution to development, immunity, neurophysiology, metabolic and nutritive support to central nervous system (CNS) health and disease. What is not generally appreciated is that (i) the ~1014 microbial cells that comprise the human microbiome outnumber human host cells by approximately one hundred-to-one; (ii) together the microbial genes of the microbiome outnumber human host genes by about one hundred-and-fifty to one; (iii) collectively these microbes constitute the largest 'diffuse organ system' in the human body, more metabolically active than the liver; strongly influencing host nutritive-, innate-immune, neuroinflammatory-, neuromodulatory- and neurotransmission-functions; and (iv) that these microbes actively secrete highly complex, immunogenic mixtures of lipopolysaccharide (LPS) and amyloid from their outer membranes into their immediate environment. While secreted LPS and amyloids are generally quite soluble as monomers over time they form into highly insoluble fibrous protein aggregates that are implicated in the progressive degenerative neuropathology of several common, age-related disorders of the human CNS including Alzheimer's disease (AD). This general commentary-perspective paper will highlight some recent findings on microbial-derived secreted LPS and amyloids and the potential contribution of these neurotoxic and proinflammatory microbial exudates to age-related inflammatory amyloidogenesis and neurodegeneration, with specific reference to AD wherever possible.}, }
@article {pmid25972851, year = {2015}, author = {Fiore, CL and Labrie, M and Jarett, JK and Lesser, MP}, title = {Transcriptional activity of the giant barrel sponge, Xestospongia muta Holobiont: molecular evidence for metabolic interchange.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {364}, doi = {10.3389/fmicb.2015.00364}, pmid = {25972851}, issn = {1664-302X}, abstract = {Compared to our understanding of the taxonomic composition of the symbiotic microbes in marine sponges, the functional diversity of these symbionts is largely unknown. Furthermore, the application of genomic, transcriptomic, and proteomic techniques to functional questions on sponge host-symbiont interactions is in its infancy. In this study, we generated a transcriptome for the host and a metatranscriptome of its microbial symbionts for the giant barrel sponge, Xestospongia muta, from the Caribbean. In combination with a gene-specific approach, our goals were to (1) characterize genetic evidence for nitrogen cycling in X. muta, an important limiting nutrient on coral reefs (2) identify which prokaryotic symbiont lineages are metabolically active and, (3) characterize the metabolic potential of the prokaryotic community. Xestospongia muta expresses genes from multiple nitrogen transformation pathways that when combined with the abundance of this sponge, and previous data on dissolved inorganic nitrogen fluxes, shows that this sponge is an important contributor to nitrogen cycling biogeochemistry on coral reefs. Additionally, we observed significant differences in gene expression of the archaeal amoA gene, which is involved in ammonia oxidation, between coral reef locations consistent with differences in the fluxes of dissolved inorganic nitrogen previously reported. In regards to symbiont metabolic potential, the genes in the biosynthetic pathways of several amino acids were present in the prokaryotic metatranscriptome dataset but in the host-derived transcripts only the catabolic reactions for these amino acids were present. A similar pattern was observed for the B vitamins (riboflavin, biotin, thiamin, cobalamin). These results expand our understanding of biogeochemical cycling in sponges, and the metabolic interchange highlighted here advances the field of symbiont physiology by elucidating specific metabolic pathways where there is high potential for host-prokaryote interactions.}, }
@article {pmid28357290, year = {2015}, author = {Zarraonaindia, I and Gilbert, JA}, title = {Understanding grapevine-microbiome interactions: implications for viticulture industry.}, journal = {Microbial cell (Graz, Austria)}, volume = {2}, number = {5}, pages = {171-173}, doi = {10.15698/mic2015.05.204}, pmid = {28357290}, issn = {2311-2638}, abstract = {Until recently, the analysis of complex communities such as that of the grapevine-microbe holobiont has been limited by the fact that most microbes are not culturable under laboratory conditions (less than 1%). However, metagenomics, the study of the genetic material recovered directly from environmental samples without the need for enrichment or of culturing, has led to open an unprecedented era in the field of microbiology. Importantly, this technological advance has now become so pervasive that it is being regularly applied to explore soils and plants of agricultural interest. Interestingly, many large companies are taking notice, with significant financial investment being used to exploring ways to manipulate the productivity, disease resistance and stress tolerance for crops by influencing the microbiome. To understand which microbes one needs to manipulate to influence this valuable characteristics, we need to sequence the microbiome and capture the genetic and hence functional metabolic information contained therein. For viticulture and other agricultural fields where the crop is also associated to particular flavor properties that may also be manipulated, understanding how the bacteria, fungi and viruses influence the development and hence chemical makeup of the crop is essential.}, }
@article {pmid25903335, year = {2015}, author = {Roossinck, MJ}, title = {Move over, bacteria! Viruses make their mark as mutualistic microbial symbionts.}, journal = {Journal of virology}, volume = {89}, number = {13}, pages = {6532-6535}, doi = {10.1128/JVI.02974-14}, pmid = {25903335}, issn = {1098-5514}, mesh = {Animals ; Bacteria/*virology ; Insecta/*virology ; Mammals/*virology ; Plants/*virology ; *Symbiosis ; *Virus Physiological Phenomena ; Viruses/*growth &amp; development ; }, abstract = {Viruses are being redefined as more than just pathogens. They are also critical symbiotic partners in the health of their hosts. In some cases, viruses have fused with their hosts in symbiogenetic relationships. Mutualistic interactions are found in plant, insect, and mammalian viruses, as well as with eukaryotic and prokaryotic microbes, and some interactions involve multiple players of the holobiont. With increased virus discovery, more mutualistic interactions are being described and more will undoubtedly be discovered.}, }
@article {pmid25894127, year = {2015}, author = {Land, WG}, title = {How evolution tells us to induce allotolerance.}, journal = {Experimental and clinical transplantation : official journal of the Middle East Society for Organ Transplantation}, volume = {13 Suppl 1}, number = {}, pages = {46-54}, pmid = {25894127}, issn = {2146-8427}, mesh = {Animals ; Bacteria/immunology ; *Evolution, Molecular ; Female ; Graft Rejection/*immunology/metabolism/prevention &amp; control ; *Graft Survival ; Host-Pathogen Interactions ; Humans ; Immunity, Innate ; Immunity, Mucosal ; Intestines/immunology/microbiology ; Models, Immunological ; Organ Transplantation/*adverse effects ; Placenta/immunology ; Pregnancy ; Signal Transduction ; *Transplantation Tolerance ; Treatment Outcome ; }, abstract = {Modern immunology, in many ways, is based on 3 major paradigms: the clonal selection theory (Medawar, Burnet; 1953/1959), the pattern recognition theory (Janeway; 1989), and the danger/injury theory (Matzinger, Land; 1994). The last theory holds that any cell stress and tissue injury including allograft injury, via induction of damage-associated molecular patterns, induces immunity including alloimmunity leading to allograft rejection. On the other hand, the concept precludes that &quot;non-self &quot; per se induces immunity as proposed by the two former theories. Today, the danger/injury model has been largely accepted by immunologists, as documented by a steadily increasing number of publications. In particular, overwhelming evidence in support of the correctness of the model has come from recent studies on the gut microbiota representing a huge assemblage of &quot;non-self. &quot; Here, harmless noninjurious commensal microbes are protected by innate immunity-based immune tolerance whereas intestinal injury-causing pathogenic microbes are immunology attacked. The ability of the immune system to discriminate between harmless beneficial &quot;non-self &quot; to induce tolerance and harmful life-threatening &quot;non-self &quot; to induce immunity has apparently emerged during evolution: Protection of innate immunity-controlled beneficial &quot;non-self &quot; (eg, as reflected by microbiotas but also by the fetus of placental mammals) as well as immune defense responses to injuring/injured &quot;non-self &quot; (eg, as reflected by plant resistance to biotic and abiotic stress and allograft rejection in mammals) evolved under pressure across the tree of life, that is, in plants, lower and higher invertebrates as well as lower and higher vertebrates. And evolution tells us why the overall existence of protected microbiotas really makes sense: It is the formation of the &quot;holobiont, &quot; - a metaorganism - that is, the host plus all of its associated microorganisms that - in terms of a strong unit of selection in evolution - provides that kind of fitness to all species on earth to successfully live, survive and reproduce. In other words: &quot;We all evolve, develop, grow, and reproduce as multigenomic ecosystems! Regarding reproduction, another impressive example of active immunologic protection of &quot;nonself &quot; refers to pregnancy in placental mammals that emerged about 400 millions of years ago. Similar to &quot;non-self &quot; microbiotas, pregnancy in placental mammals reflects an evolution-driven phenomenon on the basis of innate immunity-controlled tolerance induction to semiallogeneic non-injuring/non-injured &quot;non-self &quot; aiming to ensure reproduction! Altogether, the lesson learned from evolution of how to avoid allograft rejection is clear: prevent allograft injury to induce allotolerance, in other words: create a &quot;transplant holobiont. &quot;.}, }
@article {pmid25868684, year = {2015}, author = {Rädecker, N and Pogoreutz, C and Voolstra, CR and Wiedenmann, J and Wild, C}, title = {Nitrogen cycling in corals: the key to understanding holobiont functioning?.}, journal = {Trends in microbiology}, volume = {23}, number = {8}, pages = {490-497}, doi = {10.1016/j.tim.2015.03.008}, pmid = {25868684}, issn = {1878-4380}, mesh = {Animals ; Anthozoa/*metabolism/*microbiology ; Archaea/growth &amp; development/metabolism ; Bacteria/growth &amp; development/metabolism ; Dinoflagellida/*metabolism/physiology ; Fungi/growth &amp; development/metabolism ; Nitrogen/*metabolism ; *Nitrogen Cycle ; *Symbiosis ; }, abstract = {Corals are animals that form close mutualistic associations with endosymbiotic photosynthetic algae of the genus Symbiodinium. Together they provide the calcium carbonate framework of coral reef ecosystems. The importance of the microbiome (i.e., bacteria, archaea, fungi, and viruses) to holobiont functioning has only recently been recognized. Given that growth and density of Symbiodinium within the coral host is highly dependent on nitrogen availability, nitrogen-cycling microbes may be of fundamental importance to the stability of the coral-algae symbiosis and holobiont functioning, in particular under nutrient-enriched and -depleted scenarios. We summarize what is known about nitrogen cycling in corals and conclude that disturbance of microbial nitrogen cycling may be tightly linked to coral bleaching and disease.}, }
@article {pmid25852650, year = {2015}, author = {Balzano, S and Corre, E and Decelle, J and Sierra, R and Wincker, P and Da Silva, C and Poulain, J and Pawlowski, J and Not, F}, title = {Transcriptome analyses to investigate symbiotic relationships between marine protists.}, journal = {Frontiers in microbiology}, volume = {6}, number = {}, pages = {98}, doi = {10.3389/fmicb.2015.00098}, pmid = {25852650}, issn = {1664-302X}, abstract = {Rhizaria are an important component of oceanic plankton communities worldwide. A number of species harbor eukaryotic microalgal symbionts, which are horizontally acquired in the environment at each generation. Although these photosymbioses are determinant for Rhizaria ability to thrive in oceanic ecosystems, the mechanisms for symbiotic interactions are unclear. Using high-throughput sequencing technology (i.e., 454), we generated large Expressed Sequence Tag (EST) datasets from four uncultured Rhizaria, an acantharian (Amphilonche elongata), two polycystines (Collozoum sp. and Spongosphaera streptacantha), and one phaeodarian (Aulacantha scolymantha). We assessed the main genetic features of the host/symbionts consortium (i.e., the holobiont) transcriptomes and found rRNA sequences affiliated to a wide range of bacteria and protists in all samples, suggesting that diverse microbial communities are associated with the holobionts. A particular focus was then carried out to search for genes potentially involved in symbiotic processes such as the presence of c-type lectins-coding genes, which are proteins that play a role in cell recognition among eukaryotes. Unigenes coding putative c-type lectin domains (CTLD) were found in the species bearing photosynthetic symbionts (A. elongata, Collozoum sp., and S. streptacantha) but not in the non-symbiotic one (A. scolymantha). More particularly, phylogenetic analyses group CTLDs from A. elongata and Collozoum sp. on a distinct branch from S. streptacantha CTLDs, which contained carbohydrate-binding motifs typically observed in other marine photosymbiosis. Our data suggest that similarly to other well-known marine photosymbiosis involving metazoans, the interactions of glycans with c-type lectins is likely involved in modulation of the host/symbiont specific recognition in Radiolaria.}, }
@article {pmid25786308, year = {2014}, author = {Provorov, NA and Tikhonovich, IA}, title = {[Super-species genetic systems].}, journal = {Zhurnal obshchei biologii}, volume = {75}, number = {4}, pages = {247-260}, pmid = {25786308}, issn = {0044-4596}, mesh = {Gene Transfer, Horizontal/*physiology ; Metagenome/*physiology ; Microbial Consortia/*physiology ; *Models, Biological ; Quorum Sensing/physiology ; Symbiosis/physiology ; }, abstract = {Genetic integration of diverse organisms results in generation of three types of the super-species systems of heredity: metagenome (set of genetic factors of the microbial community which occupies a certain ecological niche), symbiogenome (functionally integrated system of the partners' symbiotic genes) and hologenome (entire hereditary system of a symbiotically originated organism). The integrity of metagenome is based on the cross-regulation and horizontal transfer of genes in co-evolving organisms which in the soil microbial communities are accompanied by maintenance of the stable extracellular DNA pool. Formation of symbiogenome is related to the highly specific partners' signaling interactions which are responsible for development of the joint metabolic pathways based on the specialized cellular and tissue structures. Transitions of symbiogenome into hologenome are due to the endosymbiotic gene transfer from microsymbionts to their hosts. In symbiotic bacteria, these transitions are coupled with establishments of multi-component, reduced and rudimentary genomes revealed for the ecologically obligatory symbionts, genetically obligatory symbionts, and cellular organelles, respectively. Their evolution is related to the stringency of transmission of microsymbionts by hosts increased from pseudo-vertical (via environment) to the trans-embryonic (via embryos and the surrounding tissues) and trans-ovarian transmission (via germ cells) which are culminated in the cytoplasmic inheritance of cellular organelles. We suggest the hypothesis about generation of endophytic plant symbiogenome on the basis of soil metagenome subjected to the control of host by its involvement into the quorum sensing auto-regulation of microbial community.}, }
@article {pmid25773891, year = {2015}, author = {Metian, M and Hédouin, L and Ferrier-Pagès, C and Teyssié, JL and Oberhansli, F and Buschiazzo, E and Warnau, M}, title = {Metal bioconcentration in the scleractinian coral Stylophora pistillata: investigating the role of different components of the holobiont using radiotracers.}, journal = {Environmental monitoring and assessment}, volume = {187}, number = {4}, pages = {178}, doi = {10.1007/s10661-015-4383-z}, pmid = {25773891}, issn = {1573-2959}, mesh = {Animals ; Anthozoa/*chemistry/physiology ; Environment ; Environmental Monitoring/*methods ; Metals/*analysis ; Water Pollutants, Chemical/*analysis ; }, abstract = {Bioconcentration kinetics of five metals (Ag, Cd, Co, Mn, and Zn) were determined in the scleractinian coral Stylophora pistillata (entire symbiotic association vs. cultured symbionts), using radiotracer techniques. Among contrasting element behaviors observed in S. pistillata, the highest efficiency of concentration and retention was observed for Ag in the symbiotic association (CFss reaching 5000 and T b½>1 year). Predominant proportion of this metal was found associated with the skeleton whereas the other metals were mainly present in the coral tissues (including host tissues and symbionts). A 96-h exposure of cultured symbionts (isolated zooxantellae from S. pistillata) indicated that they displayed a very high potential for metal bioconcentration (higher by 1 to 3 orders of magnitude compared to the skeleton). In addition, among the five elements investigated, Ag had the highest concentration factor in the cultured symbionts. Contrasting kinetic characteristics of skeleton vs. tissues offer interesting implications for biomonitoring purposes. Indeed, the skeleton was shown to display stable metal concentrations after an exposure (long retention time) and thereby allows recording contamination event on the long term, whereas the concentrations within coral tissues rapidly increased during the exposure and dropped when non-contaminating conditions were restored, allowing information on the current (short term) contamination status. The present study confirms that the coral can be seen as a two-compartment box model for metal bioconcentration: the tissues sensus latto as a first box governing metal entrance (with a crucial role played by the symbionts) and the skeleton as a second box where metal detoxification (storage) is taking place; the first box also depurates toward the environment when non-contaminating conditions are restored.}, }
@article {pmid25756121, year = {2014}, author = {Nguyen-Kim, H and Bouvier, T and Bouvier, C and Doan-Nhu, H and Nguyen-Ngoc, L and Rochelle-Newall, E and Baudoux, AC and Desnues, C and Reynaud, S and Ferrier-Pages, C and Bettarel, Y}, title = {High occurrence of viruses in the mucus layer of scleractinian corals.}, journal = {Environmental microbiology reports}, volume = {6}, number = {6}, pages = {675-682}, pmid = {25756121}, issn = {1758-2229}, mesh = {Animals ; Anthozoa/*virology ; Bacteria/classification/genetics/isolation &amp; purification ; Biodiversity ; Molecular Sequence Data ; Phylogeny ; Viruses/classification/genetics/*isolation &amp; purification ; }, abstract = {Viruses attract increasing interest from environmental microbiologists seeking to understand their function and role in coral health. However, little is known about their main ecological traits within the coral holobiont. In this study, a quantitative and qualitative characterization of viral and bacterial communities was conducted on the mucus of seven different coral species of the Van Phong Bay (Vietnam). On average, the concentrations of viruses and bacteria were, respectively, 17- and twofold higher in the mucus than in the surrounding water. The examination of bacterial community composition also showed remarkable differences between mucus and water samples. The percentage of active respiring cells was nearly threefold higher in mucus (m = 24.8%) than in water (m = 8.6%). Interestingly, a positive and highly significant correlation was observed between the proportion of active cells and viral abundance in the mucus, suggesting that the metabolism of the bacterial associates is probably a strong determinant of the distribution of viruses within the coral holobiont. Overall, coral mucus, given its unique physicochemical characteristics and sticking properties, can be regarded as a highly selective biotope for abundant, diversified and specialized symbiotic microbial and viral organisms.}, }
@article {pmid25745427, year = {2015}, author = {Wichard, T and Charrier, B and Mineur, F and Bothwell, JH and Clerck, OD and Coates, JC}, title = {The green seaweed Ulva: a model system to study morphogenesis.}, journal = {Frontiers in plant science}, volume = {6}, number = {}, pages = {72}, doi = {10.3389/fpls.2015.00072}, pmid = {25745427}, issn = {1664-462X}, abstract = {Green macroalgae, mostly represented by the Ulvophyceae, the main multicellular branch of the Chlorophyceae, constitute important primary producers of marine and brackish coastal ecosystems. Ulva or sea lettuce species are some of the most abundant representatives, being ubiquitous in coastal benthic communities around the world. Nonetheless the genus also remains largely understudied. This review highlights Ulva as an exciting novel model organism for studies of algal growth, development and morphogenesis as well as mutualistic interactions. The key reasons that Ulva is potentially such a good model system are: (i) patterns of Ulva development can drive ecologically important events, such as the increasing number of green tides observed worldwide as a result of eutrophication of coastal waters, (ii) Ulva growth is symbiotic, with proper development requiring close association with bacterial epiphytes, (iii) Ulva is extremely developmentally plastic, which can shed light on the transition from simple to complex multicellularity and (iv) Ulva will provide additional information about the evolution of the green lineage.}, }
@article {pmid25737238, year = {2015}, author = {Wang, J and Kalyan, S and Steck, N and Turner, LM and Harr, B and Künzel, S and Vallier, M and Häsler, R and Franke, A and Oberg, HH and Ibrahim, SM and Grassl, GA and Kabelitz, D and Baines, JF}, title = {Analysis of intestinal microbiota in hybrid house mice reveals evolutionary divergence in a vertebrate hologenome.}, journal = {Nature communications}, volume = {6}, number = {}, pages = {6440}, doi = {10.1038/ncomms7440}, pmid = {25737238}, issn = {2041-1723}, mesh = {Animals ; Base Sequence ; *Biological Evolution ; Crosses, Genetic ; DNA Primers/genetics ; Flow Cytometry ; Gastrointestinal Microbiome/*genetics ; Genetics, Population ; Genome/*genetics ; Germany ; Hybridization, Genetic/*genetics ; Mice/*genetics/microbiology ; *Models, Genetic ; Molecular Sequence Data ; Quantitative Trait Loci ; Selection, Genetic ; Sequence Analysis, DNA ; Species Specificity ; }, abstract = {Recent evidence suggests that natural selection operating on hosts to maintain their microbiome contributes to the emergence of new species, that is, the 'hologenomic basis of speciation'. Here we analyse the gut microbiota of two house mice subspecies, Mus musculus musculus and M. m. domesticus, across their Central European hybrid zone, in addition to hybrids generated in the lab. Hybrid mice display widespread transgressive phenotypes (that is, exceed or fall short of parental values) in a variety of measures of bacterial community structure, which reveals the importance of stabilizing selection operating on the intestinal microbiome within species. Further genetic and immunological analyses reveal genetic incompatibilities, aberrant immune gene expression and increased intestinal pathology associated with altered community structure among hybrids. These results provide unique insight into the consequences of evolutionary divergence in a vertebrate 'hologenome', which may be an unrecognized contributing factor to reproductive isolation in this taxonomic group.}, }
@article {pmid25732740, year = {2015}, author = {Bosch, TC and Grasis, JA and Lachnit, T}, title = {Microbial ecology in Hydra: why viruses matter.}, journal = {Journal of microbiology (Seoul, Korea)}, volume = {53}, number = {3}, pages = {193-200}, doi = {10.1007/s12275-015-4695-2}, pmid = {25732740}, issn = {1976-3794}, support = {F32 AI098418/AI/NIAID NIH HHS/United States ; 5F32AI098418/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacteriophages/*physiology ; Biological Evolution ; Cnidaria/*virology ; Hydra/*virology ; Hydrobiology ; Microbiota/physiology ; Species Specificity ; *Symbiosis ; *Virus Physiological Phenomena ; }, abstract = {While largely studied because of their harmful effects on human health, there is growing appreciation that viruses are also important members of the animal holobiont. This review highlights recent findings on viruses associated with Hydra and related Cnidaria. These early evolutionary diverging animals not only select their bacterial communities but also select for viral communities in a species-specific manner. The majority of the viruses associating with these animals are bacteriophages. We demonstrate that the animal host and its virome have evolved into a homeostatic, symbiotic relationship and propose that viruses are an important part of the Hydra holobiont by controlling the species-specific microbiome. We conclude that beneficial virus-bacterial-host interactions should be considered as an integral part of animal development and evolution.}, }
@article {pmid25724277, year = {2015}, author = {Peterson, BF and Stewart, HL and Scharf, ME}, title = {Quantification of symbiotic contributions to lower termite lignocellulose digestion using antimicrobial treatments.}, journal = {Insect biochemistry and molecular biology}, volume = {59}, number = {}, pages = {80-88}, doi = {10.1016/j.ibmb.2015.02.009}, pmid = {25724277}, issn = {1879-0240}, mesh = {Animals ; Anti-Bacterial Agents/*pharmacology ; Bacteria/*drug effects/metabolism ; Gastrointestinal Tract/metabolism/microbiology ; Isoptera/*drug effects/metabolism/microbiology ; Lignin/*metabolism ; Symbiosis ; }, abstract = {Animal-microbe co-evolution and symbiosis are broadly distributed across the animal kingdom. Insects form a myriad of associations with microbes ranging from vectoring of pathogens to intracellular, mutualistic relationships. Lower termites are key models for insect-microbe symbiosis because of the diversity, complexity and functionality of their unique tripartite symbiosis. This collaboration allows termites to live on a diet of nitrogen-poor lignocellulose. Recent functional investigations of lignocellulose digestion in lower termites have primarily focused on the contributions of the eukaryotic members of the termite holobiont (termite and protist). Here, using multiple antimicrobial treatments, we induced differing degrees of dysbiosis in the termite gut, leading to variably altered symbiont abundance and diversity, and lignocellulolytic capacity. Although protists are clearly affected by antimicrobial treatments, our findings provide novel evidence that the removal of distinct groups of bacteria partially reduces, but does not abolish, the saccharolytic potential of the termite gut holobiont. This is specifically manifested by reductions of 23-47% and 30-52% in glucose and xylose yields respectively from complex lignocellulose. Thus, all members of the lower termite holobiont (termite, protist and prokaryotes) are involved in the process of efficient, sustained lignocellulase activity. This unprecedented quantification of the relative importance of prokaryotes in this system emphasizes the collaborative nature of the termite holobiont, and the relevance of lower termites as models for inter-domain symbioses.}, }
@article {pmid25673681, year = {2015}, author = {Dheilly, NM and Maure, F and Ravallec, M and Galinier, R and Doyon, J and Duval, D and Leger, L and Volkoff, AN and Missé, D and Nidelet, S and Demolombe, V and Brodeur, J and Gourbal, B and Thomas, F and Mitta, G}, title = {Who is the puppet master? Replication of a parasitic wasp-associated virus correlates with host behaviour manipulation.}, journal = {Proceedings. Biological sciences}, volume = {282}, number = {1803}, pages = {20142773}, doi = {10.1098/rspb.2014.2773}, pmid = {25673681}, issn = {1471-2954}, mesh = {Animals ; Coleoptera/*parasitology/physiology/*virology ; Female ; Host-Parasite Interactions ; Larva/parasitology/virology ; Molecular Sequence Data ; Oviducts/virology ; RNA Viruses/*physiology ; Wasps/physiology/*virology ; }, abstract = {Many parasites modify their host behaviour to improve their own transmission and survival, but the proximate mechanisms remain poorly understood. An original model consists of the parasitoid Dinocampus coccinellae and its coccinellid host, Coleomegilla maculata; during the behaviour manipulation, the parasitoid is not in contact with its host anymore. We report herein the discovery and characterization of a new RNA virus of the parasitoid (D. coccinellae paralysis virus, DcPV). Using a combination of RT-qPCR and transmission electron microscopy, we demonstrate that DcPV is stored in the oviduct of parasitoid females, replicates in parasitoid larvae and is transmitted to the host during larval development. Next, DcPV replication in the host's nervous tissue induces a severe neuropathy and antiviral immune response that correlate with the paralytic symptoms characterizing the behaviour manipulation. Remarkably, virus clearance correlates with recovery of normal coccinellid behaviour. These results provide evidence that changes in ladybeetle behaviour most likely result from DcPV replication in the cerebral ganglia rather than by manipulation by the parasitoid. This offers stimulating prospects for research on parasitic manipulation by suggesting for the first time that behaviour manipulation could be symbiont-mediated.}, }
@article {pmid25668159, year = {2015}, author = {Pantos, O and Bongaerts, P and Dennis, PG and Tyson, GW and Hoegh-Guldberg, O}, title = {Habitat-specific environmental conditions primarily control the microbiomes of the coral Seriatopora hystrix.}, journal = {The ISME journal}, volume = {9}, number = {9}, pages = {1916-1927}, doi = {10.1038/ismej.2015.3}, pmid = {25668159}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*microbiology ; Archaea/genetics ; Australia ; *Coral Reefs ; Gammaproteobacteria/genetics ; Genotype ; Microbiota/*genetics ; Porcupines ; RNA, Ribosomal, 16S/genetics ; Rhodobacteraceae/genetics ; }, abstract = {Reef-building corals form complex relationships with a range of microorganisms including bacteria, archaea, fungi and the unicellular microalgae of the genus Symbiodinium, which together form the coral holobiont. These symbionts are known to have both beneficial and deleterious effects on their coral host, but little is known about what the governing factors of these relationships are, or the interactions that exist between the different members of the holobiont and their environment. Here we used 16S ribosomal RNA gene amplicon sequencing to investigate how archaeal and bacterial communities associated with the widespread scleractinian coral Seriatopora hystrix are influenced by extrinsic (reef habitat and geographic location) and intrinsic (host genotype and Symbiodinium subclade) factors. Bacteria dominate the microbiome of S. hystrix, with members of the Alphaproteobacteria, Gammaproteobacteria and Bacteriodetes being the most predominant in all samples. The richness and evenness of these communities varied between reef habitats, but there was no significant difference between distinct coral host lineages or corals hosting distinct Symbiodinium subclades. The coral microbiomes correlated to reef habitat (depth) and geographic location, with a negative correlation between Alpha- and Gammaproteobacteria, driven by the key members of both groups (Rhodobacteraceae and Hahellaceae, respectively), which showed significant differences between location and depth. This study suggests that the control of microbial communities associated with the scleractinian coral S. hystrix is driven primarily by external environmental conditions rather than by those directly associated with the coral holobiont.}, }
@article {pmid25655016, year = {2015}, author = {Vandenkoornhuyse, P and Quaiser, A and Duhamel, M and Le Van, A and Dufresne, A}, title = {The importance of the microbiome of the plant holobiont.}, journal = {The New phytologist}, volume = {206}, number = {4}, pages = {1196-1206}, doi = {10.1111/nph.13312}, pmid = {25655016}, issn = {1469-8137}, mesh = {Biological Evolution ; *Microbiota ; Plants/*microbiology ; }, abstract = {Plants can no longer be considered as standalone entities and a more holistic perception is needed. Indeed, plants harbor a wide diversity of microorganisms both inside and outside their tissues, in the endosphere and ectosphere, respectively. These microorganisms, which mostly belong to Bacteria and Fungi, are involved in major functions such as plant nutrition and plant resistance to biotic and abiotic stresses. Hence, the microbiota impact plant growth and survival, two key components of fitness. Plant fitness is therefore a consequence of the plant per se and its microbiota, which collectively form a holobiont. Complementary to the reductionist perception of evolutionary pressures acting on plant or symbiotic compartments, the plant holobiont concept requires a novel perception of evolution. The interlinkages between the plant holobiont components are explored here in the light of current ecological and evolutionary theories. Microbiome complexity and the rules of microbiotic community assemblage are not yet fully understood. It is suggested that the plant can modulate its microbiota to dynamically adjust to its environment. To better understand the level of plant dependence on the microbiotic components, the core microbiota need to be determined at different hierarchical scales of ecology while pan-microbiome analyses would improve characterization of the functions displayed.}, }
@article {pmid25621279, year = {2014}, author = {Thompson, JR and Rivera, HE and Closek, CJ and Medina, M}, title = {Microbes in the coral holobiont: partners through evolution, development, and ecological interactions.}, journal = {Frontiers in cellular and infection microbiology}, volume = {4}, number = {}, pages = {176}, doi = {10.3389/fcimb.2014.00176}, pmid = {25621279}, issn = {2235-2988}, mesh = {Animals ; Anthozoa/genetics/*microbiology ; Bacteria/classification/genetics/isolation &amp; purification ; *Bacterial Physiological Phenomena ; *Biological Evolution ; *Ecosystem ; Symbiosis ; }, abstract = {In the last two decades, genetic and genomic studies have revealed the astonishing diversity and ubiquity of microorganisms. Emergence and expansion of the human microbiome project has reshaped our thinking about how microbes control host health-not only as pathogens, but also as symbionts. In coral reef environments, scientists have begun to examine the role that microorganisms play in coral life history. Herein, we review the current literature on coral-microbe interactions within the context of their role in evolution, development, and ecology. We ask the following questions, first posed by McFall-Ngai et al. (2013) in their review of animal evolution, with specific attention to how coral-microbial interactions may be affected under future environmental conditions: (1) How do corals and their microbiome affect each other's genomes? (2) How does coral development depend on microbial partners? (3) How is homeostasis maintained between corals and their microbial symbionts? (4) How can ecological approaches deepen our understanding of the multiple levels of coral-microbial interactions? Elucidating the role that microorganisms play in the structure and function of the holobiont is essential for understanding how corals maintain homeostasis and acclimate to changing environmental conditions.}, }
@article {pmid25615440, year = {2015}, author = {Tout, J and Jeffries, TC and Petrou, K and Tyson, GW and Webster, NS and Garren, M and Stocker, R and Ralph, PJ and Seymour, JR}, title = {Chemotaxis by natural populations of coral reef bacteria.}, journal = {The ISME journal}, volume = {9}, number = {8}, pages = {1764-1777}, doi = {10.1038/ismej.2014.261}, pmid = {25615440}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/*drug effects/genetics ; Chemotactic Factors/pharmacology ; Chemotaxis/*drug effects ; *Coral Reefs ; DNA, Bacterial/analysis ; Metagenome ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Seawater/microbiology ; Sulfonium Compounds/pharmacology ; Vibrio/genetics ; }, abstract = {Corals experience intimate associations with distinct populations of marine microorganisms, but the microbial behaviours underpinning these relationships are poorly understood. There is evidence that chemotaxis is pivotal to the infection process of corals by pathogenic bacteria, but this evidence is limited to experiments using cultured isolates under laboratory conditions. We measured the chemotactic capabilities of natural populations of coral-associated bacteria towards chemicals released by corals and their symbionts, including amino acids, carbohydrates, ammonium and dimethylsulfoniopropionate (DMSP). Laboratory experiments, using a modified capillary assay, and in situ measurements, using a novel microfabricated in situ chemotaxis assay, were employed to quantify the chemotactic responses of natural microbial assemblages on the Great Barrier Reef. Both approaches showed that bacteria associated with the surface of the coral species Pocillopora damicornis and Acropora aspera exhibited significant levels of chemotaxis, particularly towards DMSP and amino acids, and that these levels of chemotaxis were significantly higher than that of bacteria inhabiting nearby, non-coral-associated waters. This pattern was supported by a significantly higher abundance of chemotaxis and motility genes in metagenomes within coral-associated water types. The phylogenetic composition of the coral-associated chemotactic microorganisms, determined using 16S rRNA amplicon pyrosequencing, differed from the community in the seawater surrounding the coral and comprised known coral associates, including potentially pathogenic Vibrio species. These findings indicate that motility and chemotaxis are prevalent phenotypes among coral-associated bacteria, and we propose that chemotaxis has an important role in the establishment and maintenance of specific coral-microbe associations, which may ultimately influence the health and stability of the coral holobiont.}, }
@article {pmid25548731, year = {2014}, author = {Freeman, CJ and Easson, CG and Baker, DM}, title = {Metabolic diversity and niche structure in sponges from the Miskito Cays, Honduras.}, journal = {PeerJ}, volume = {2}, number = {}, pages = {e695}, doi = {10.7717/peerj.695}, pmid = {25548731}, issn = {2167-8359}, abstract = {Hosting symbionts provides many eukaryotes with access to the products of microbial metabolism that are crucial for host performance. On tropical coral reefs, many (High Microbial Abundance [HMA]) but not all (Low Microbial Abundance [LMA]) marine sponges host abundant symbiont communities. Although recent research has revealed substantial variation in these sponge-microbe associations (termed holobionts), little is known about the ecological implications of this diversity. We investigated the expansion of diverse sponge species across isotopic niche space by calculating niche size (as standard ellipse area [SEA c ]) and assessing the relative placement of common sponge species in bivariate (δ (13)C and δ (15)N) plots. Sponges for this study were collected from the relatively isolated reefs within the Miskito Cays of Honduras. These reefs support diverse communities of HMA and LMA species that together span a gradient of photosymbiont abundance, as revealed by chlorophyll a analysis. HMA sponges occupied unique niche space compared to LMA species, but the placement of some HMA sponges was driven by photosymbiont abundance. In addition, photosymbiont abundance explained a significant portion of the variation in isotope values, suggesting that access to autotrophic metabolism provided by photosymbionts is an important predictor in the location of species within isotopic space. Host identity accounted for over 70% of the variation in isotope values within the Miskito Cays and there was substantial variation in the placement of individual species within isotopic niche space, suggesting that holobiont metabolic diversity may allow taxonomically diverse sponge species to utilize unique sources of nutrients within a reef system. This study provides initial evidence that microbial symbionts allow sponges to expand into novel physiochemical niche space. This expansion may reduce competitive interactions within coral reefs and promote diversification of these communities.}, }
@article {pmid25477868, year = {2014}, author = {Hardoim, CC and Cardinale, M and Cúcio, AC and Esteves, AI and Berg, G and Xavier, JR and Cox, CJ and Costa, R}, title = {Effects of sample handling and cultivation bias on the specificity of bacterial communities in keratose marine sponges.}, journal = {Frontiers in microbiology}, volume = {5}, number = {}, pages = {611}, doi = {10.3389/fmicb.2014.00611}, pmid = {25477868}, issn = {1664-302X}, abstract = {Complex and distinct bacterial communities inhabit marine sponges and are believed to be essential to host survival, but our present-day inability to domesticate sponge symbionts in the laboratory hinders our access to the full metabolic breadth of these microbial consortia. We address bacterial cultivation bias in marine sponges using a procedure that enables direct comparison between cultivated and uncultivated symbiont community structures. Bacterial community profiling of the sympatric keratose species Sarcotragus spinosulus and Ircinia variabilis (Dictyoceratida, Irciniidae) was performed by polymerase chain reaction-denaturing gradient gel electrophoresis and 454-pyrosequecing of 16S rRNA gene fragments. Whereas cultivation-independent methods revealed species-specific bacterial community structures in these hosts, cultivation-dependent methods resulted in equivalent community assemblages from both species. Between 15 and 18 bacterial phyla were found in S. spinosulus and I. variabilis using cultivation-independent methods. However, Alphaproteobacteria and Gammaproteobacteria dominated the cultivation-dependent bacterial community. While cultivation-independent methods revealed about 200 and 220 operational taxonomic units (OTUs, 97% gene similarity) in S. spinosulus and I. variabilis, respectively, only 33 and 39 OTUs were found in these species via culturing. Nevertheless, around 50% of all cultured OTUs escaped detection by cultivation-independent methods, indicating that standard cultivation makes otherwise host-specific bacterial communities similar by selectively enriching for rarer and generalist symbionts. This study sheds new light on the diversity spectrum encompassed by cultivated and uncultivated sponge-associated bacteria. Moreover, it highlights the need to develop alternative culturing technologies to capture the dominant sponge symbiont fraction that currently remains recalcitrant to laboratory manipulation.}, }
@article {pmid25467196, year = {2014}, author = {Rosic, N and Kaniewska, P and Chan, CK and Ling, EY and Edwards, D and Dove, S and Hoegh-Guldberg, O}, title = {Early transcriptional changes in the reef-building coral Acropora aspera in response to thermal and nutrient stress.}, journal = {BMC genomics}, volume = {15}, number = {}, pages = {1052}, doi = {10.1186/1471-2164-15-1052}, pmid = {25467196}, issn = {1471-2164}, mesh = {Animals ; Anthozoa/*genetics/metabolism ; Computational Biology ; Coral Reefs ; Energy Metabolism ; Gene Expression Profiling ; *Gene Expression Regulation ; Molecular Sequence Annotation ; Oxidation-Reduction ; Photosynthesis ; Stress, Physiological/*genetics ; Temperature ; *Transcription, Genetic ; }, abstract = {BACKGROUND: Changes to the environment as a result of human activities can result in a range of impacts on reef building corals that include coral bleaching (reduced concentrations of algal symbionts), decreased coral growth and calcification, and increased incidence of diseases and mortality. Understanding how elevated temperatures and nutrient concentration affect early transcriptional changes in corals and their algal endosymbionts is critically important for evaluating the responses of coral reefs to global changes happening in the environment. Here, we investigated the expression of genes in colonies of the reef-building coral Acropora aspera exposed to short-term sub-lethal levels of thermal (+6°C) and nutrient stress (ammonium-enrichment: 20 μM).<br><br>RESULTS: The RNA-Seq data provided hundreds of differentially expressed genes (DEGs) corresponding to various stress regimes, with 115 up- and 78 down-regulated genes common to all stress regimes. A list of DEGs included up-regulated coral genes like cytochrome c oxidase and NADH-ubiquinone oxidoreductase and up-regulated photosynthetic genes of algal origin, whereas coral GFP-like fluorescent chromoprotein and sodium/potassium-transporting ATPase showed reduced transcript levels. Taxonomic analyses of the coral holobiont disclosed the dominant presence of transcripts from coral (~70%) and Symbiodinium (~10-12%), as well as ~15-20% of unknown sequences which lacked sequence identity to known genes. Gene ontology analyses revealed enriched pathways, which led to changes in the dynamics of protein networks affecting growth, cellular processes, and energy requirement.<br><br>CONCLUSIONS: In corals with preserved symbiont physiological performance (based on Fv/Fm, photo-pigment and symbiont density), transcriptomic changes and DEGs provided important insight into early stages of the stress response in the coral holobiont. Although there were no signs of coral bleaching after exposure to short-term thermal and nutrient stress conditions, we managed to detect oxidative stress and apoptotic changes on a molecular level and provide a list of prospective stress biomarkers for both partners in symbiosis. Consequently, our findings are important for understanding and anticipating impacts of anthropogenic global climate change on coral reefs.}, }
@article {pmid25467066, year = {2015}, author = {Iluz, D and Dubinsky, Z}, title = {Coral photobiology: new light on old views.}, journal = {Zoology (Jena, Germany)}, volume = {118}, number = {2}, pages = {71-78}, doi = {10.1016/j.zool.2014.08.003}, pmid = {25467066}, issn = {1873-2720}, mesh = {Acclimatization/physiology ; Animals ; Anthozoa/*physiology ; Calcification, Physiologic/physiology ; Chlorophyta/physiology ; Energy Metabolism ; *Light ; Photobiology ; Photosynthesis/physiology ; *Symbiosis ; }, abstract = {The relationship between reef-building corals and light-harvesting pigments of zooxanthellae (Symbiodinium sp.) has been acknowledged for decades. The photosynthetic activity of the algal endocellular symbionts may provide up to 90% of the energy needed for the coral holobiont. This relationship limits the bathymetric distribution of coral reefs to the upper 100 m of tropical shorelines. However, even corals growing under high light intensities have to supplement the photosynthates translocated from the algae by predation on nutrient-rich zooplankton. New information has revealed how the fate of carbon acquired through photosynthesis differs from that secured by predation, whose rates are controlled by light-induced tentacular extension. The Goreau paradigm of &quot;light-enhanced calcification&quot; is being reevaluated, based on evidence that blue light stimulates coral calcification independently from photosynthesis rates. Furthermore, under dim light, calcification rates were stoichiometrically uncoupled from photosynthesis. The rates of photosynthesis of the zooxanthellae exhibit a clear endogenous rhythmicity maintained by light patterns. This daily pattern is concomitant with a periodicity of all the antioxidant protective mechanisms that wax and wane to meet the concomitant fluctuation in oxygen evolution. The phases of the moon are involved in the triggering of coral reproduction and control the spectacular annual mass-spawning events taking place in several reefs. The intensity and directionality of the underwater light field affect the architecture of coral colonies, leading to an optimization of the exposure of the zooxanthellae to light. We present a summary of major gaps in our understanding of the relationship between light and corals as a roadmap for future research.}, }
@article {pmid25431341, year = {2015}, author = {Hoppers, A and Stoudenmire, J and Wu, S and Lopanik, NB}, title = {Antibiotic activity and microbial community of the temperate sponge, Haliclona sp.}, journal = {Journal of applied microbiology}, volume = {118}, number = {2}, pages = {419-430}, doi = {10.1111/jam.12709}, pmid = {25431341}, issn = {1365-2672}, mesh = {Animals ; Anti-Bacterial Agents/isolation &amp; purification/*pharmacology ; Bacteria/genetics/isolation &amp; purification ; Haliclona/chemistry/genetics/*microbiology ; Seawater/microbiology ; }, abstract = {AIMS: Sessile marine invertebrates engage in a diverse array of beneficial interactions with bacterial symbionts. One feature of some of these relationships is the presence of bioactive natural products that can defend the holobiont from predation, competition or disease. In this study, we investigated the antimicrobial activity and microbial community of a common temperate sponge from coastal North Carolina.<br><br>METHODS AND RESULTS: The sponge was identified as a member of the genus Haliclona, a prolific source of bioactive natural products, based on its 18S rRNA gene sequence. The crude chemical extract and methanol partition had broad activity against the assayed Gram-negative and Gram-positive pathogenic bacteria. Further fractionation resulted in two groups of compounds with differing antimicrobial activity, primarily against Gram-positive test organisms. There was, however, notable activity against the Gram-negative marine pathogen, Vibrio parahaemolyticus. Microbial community analysis of the sponge and surrounding sea water via denaturing gradient gel electrophoresis (DGGE) indicates that it harbours a distinct group of bacterial associates.<br><br>CONCLUSIONS: The common temperate sponge, Haliclona sp., is a source of multiple antimicrobial compounds and has some consistent microbial community members that may play a role in secondary metabolite production.<br><br>These data suggest that common temperate sponges can be a source of bioactive chemical and microbial diversity. Further studies may reveal the importance of the microbial associates to the sponge and natural product biosynthesis.}, }
@article {pmid25430522, year = {2016}, author = {Salvucci, E}, title = {Microbiome, holobiont and the net of life.}, journal = {Critical reviews in microbiology}, volume = {42}, number = {3}, pages = {485-494}, doi = {10.3109/1040841X.2014.962478}, pmid = {25430522}, issn = {1549-7828}, mesh = {Animals ; Bacteria/classification/genetics/isolation &amp; purification ; *Bacterial Physiological Phenomena ; Biological Evolution ; Humans ; *Microbiota ; *Symbiosis ; }, abstract = {Holistic emerging approaches allow us to understand that every organism is the result of integration mechanisms observed at every level of nature: integration of DNA from virus and bacteria in metazoans, endosymbiotic relationships and holobionts. Horizontal gene transfer events in Bacteria, Archaea and Eukaryotes have resulted in the chimeric nature of genomes. As a continuity of this genomic landscape, the human body contains more bacterial than human cells. Human microbiome has co-evolved with the human being as a unity called holobiont. The loss of part of our microbiome along evolution can explain the continuous increasing incidence of immune and inflammatory-related diseases. Life is a continuous process in which the organism experiences its environment and this interaction impacts in the epigenetic system and the genomic structure. The emerging perspectives restitute the great importance of Lamarck's theoretical contributions (the milieu) and Darwin's pangenesis theory.}, }
@article {pmid25401092, year = {2014}, author = {Stilling, RM and Bordenstein, SR and Dinan, TG and Cryan, JF}, title = {Friends with social benefits: host-microbe interactions as a driver of brain evolution and development?.}, journal = {Frontiers in cellular and infection microbiology}, volume = {4}, number = {}, pages = {147}, doi = {10.3389/fcimb.2014.00147}, pmid = {25401092}, issn = {2235-2988}, support = {R01 GM085163/GM/NIGMS NIH HHS/United States ; R01GM085163/GM/NIGMS NIH HHS/United States ; }, mesh = {Adaptation, Biological ; Animals ; Behavior ; *Biological Evolution ; Brain/*physiology ; Epigenesis, Genetic ; Gene-Environment Interaction ; Host-Pathogen Interactions/*physiology ; Humans ; Microbiota ; Symbiosis ; }, abstract = {The tight association of the human body with trillions of colonizing microbes that we observe today is the result of a long evolutionary history. Only very recently have we started to understand how this symbiosis also affects brain function and behavior. In this hypothesis and theory article, we propose how host-microbe associations potentially influenced mammalian brain evolution and development. In particular, we explore the integration of human brain development with evolution, symbiosis, and RNA biology, which together represent a &quot;social triangle&quot; that drives human social behavior and cognition. We argue that, in order to understand how inter-kingdom communication can affect brain adaptation and plasticity, it is inevitable to consider epigenetic mechanisms as important mediators of genome-microbiome interactions on an individual as well as a transgenerational time scale. Finally, we unite these interpretations with the hologenome theory of evolution. Taken together, we propose a tighter integration of neuroscience fields with host-associated microbiology by taking an evolutionary perspective.}, }
@article {pmid25387109, year = {2015}, author = {Denman, SE and McSweeney, CS}, title = {The early impact of genomics and metagenomics on ruminal microbiology.}, journal = {Annual review of animal biosciences}, volume = {3}, number = {}, pages = {447-465}, doi = {10.1146/annurev-animal-022114-110705}, pmid = {25387109}, issn = {2165-8110}, mesh = {Animals ; Dietary Fiber/metabolism ; Genomics ; Methane/biosynthesis ; Microbiota/*genetics ; Phylogeny ; Rumen/*microbiology ; Ruminants/*microbiology ; }, abstract = {Knowledge gained from early and recent studies that define the functions of microbial populations within the rumen microbiome is essential to allow for directed rumen manipulation strategies. A large number of omic studies have focused on carbohydrate active enzymes either for improved fiber digestion within the animal or for use in industries such as biofuels. Studies of the rumen microbiome with respect to methane production and abatement strategies have led to initiatives for defining the microbiome of low- and high-methane-emitting animals while ensuring optimal feed conversion. With advances in omic technologies, the ability to link host genetics and the rumen microbiome by studying all the biological components (holobiont) through the use of hologenomics has begun. However, a program to culture and isolate microbial species for the purpose of standard microbial characterization to aid in assigning function to genomic data remains critical, especially for genes of unknown function.}, }
@article {pmid25360746, year = {2014}, author = {Schrameyer, V and Wangpraseurt, D and Hill, R and Kühl, M and Larkum, AW and Ralph, PJ}, title = {Light respiratory processes and gross photosynthesis in two scleractinian corals.}, journal = {PloS one}, volume = {9}, number = {10}, pages = {e110814}, doi = {10.1371/journal.pone.0110814}, pmid = {25360746}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*metabolism/physiology/*radiation effects ; Biological Transport/radiation effects ; Carbon Dioxide/metabolism ; *Light ; Oxygen/metabolism ; Photosynthesis/*radiation effects ; Respiration/*radiation effects ; Symbiosis/radiation effects ; }, abstract = {The light dependency of respiratory activity of two scleractinian corals was examined using O2 microsensors and CO2 exchange measurements. Light respiration increased strongly but asymptotically with elevated irradiance in both species. Light respiration in Pocillopora damicornis was higher than in Pavona decussata under low irradiance, indicating species-specific differences in light-dependent metabolic processes. Overall, the coral P. decussata exhibited higher CO2 uptake rates than P. damicornis over the experimental irradiance range. P. decussata also harboured twice as many algal symbionts and higher total protein biomass compared to P. damicornis, possibly resulting in self-shading of the symbionts and/or changes in host tissue specific light distribution. Differences in light respiration and CO2 availability could be due to host-specific characteristics that modulate the symbiont microenvironment, its photosynthesis, and hence the overall performance of the coral holobiont.}, }
@article {pmid25343582, year = {2014}, author = {Grasis, JA and Lachnit, T and Anton-Erxleben, F and Lim, YW and Schmieder, R and Fraune, S and Franzenburg, S and Insua, S and Machado, G and Haynes, M and Little, M and Kimble, R and Rosenstiel, P and Rohwer, FL and Bosch, TC}, title = {Species-specific viromes in the ancestral holobiont Hydra.}, journal = {PloS one}, volume = {9}, number = {10}, pages = {e109952}, doi = {10.1371/journal.pone.0109952}, pmid = {25343582}, issn = {1932-6203}, support = {F32 AI098418/AI/NIAID NIH HHS/United States ; 1F32AI098518/AI/NIAID NIH HHS/United States ; 1R21AI094534/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Bacteria/isolation &amp; purification/virology ; Bacteriophages/genetics/isolation &amp; purification/metabolism ; Hydra/metabolism/microbiology/ultrastructure/*virology ; Reproducibility of Results ; Sequence Analysis, DNA ; Species Specificity ; *Symbiosis ; Viruses/genetics/isolation &amp; purification/*metabolism ; }, abstract = {Recent evidence showing host specificity of colonizing bacteria supports the view that multicellular organisms are holobionts comprised of the macroscopic host in synergistic interdependence with a heterogeneous and host-specific microbial community. Whereas host-bacteria interactions have been extensively investigated, comparatively little is known about host-virus interactions and viral contribution to the holobiont. We sought to determine the viral communities associating with different Hydra species, whether these viral communities were altered with environmental stress, and whether these viruses affect the Hydra-associated holobiont. Here we show that each species of Hydra harbors a diverse host-associated virome. Primary viral families associated with Hydra are Myoviridae, Siphoviridae, Inoviridae, and Herpesviridae. Most Hydra-associated viruses are bacteriophages, a reflection of their involvement in the holobiont. Changes in environmental conditions alter the associated virome, increase viral diversity, and affect the metabolism of the holobiont. The specificity and dynamics of the virome point to potential viral involvement in regulating microbial associations in the Hydra holobiont. While viruses are generally regarded as pathogenic agents, our study suggests an evolutionary conserved ability of viruses to function as holobiont regulators and, therefore, constitutes an emerging paradigm shift in host-microbe interactions.}, }
@article {pmid25309882, year = {2014}, author = {Apidianakis, Y and Ferrandon, D}, title = {Modeling hologenome imbalances in inflammation and cancer.}, journal = {Frontiers in cellular and infection microbiology}, volume = {4}, number = {}, pages = {134}, doi = {10.3389/fcimb.2014.00134}, pmid = {25309882}, issn = {2235-2988}, mesh = {Animals ; Humans ; Inflammation/*complications/*etiology ; Neoplasms/*complications/*etiology ; }, }
@article {pmid25278474, year = {2014}, author = {Grover, R and Ferrier-Pagès, C and Maguer, JF and Ezzat, L and Fine, M}, title = {Nitrogen fixation in the mucus of Red Sea corals.}, journal = {The Journal of experimental biology}, volume = {217}, number = {Pt 22}, pages = {3962-3963}, doi = {10.1242/jeb.111591}, pmid = {25278474}, issn = {1477-9145}, mesh = {Animals ; Anthozoa/*microbiology/physiology ; Dinoflagellida/*metabolism ; Indian Ocean ; Mucus ; Nitrogen/*analysis ; *Nitrogen Fixation ; Nitrogen Isotopes ; Seawater/*chemistry ; Symbiosis ; }, abstract = {Scleractinian corals are essential constituents of tropical reef ecological diversity. They live in close association with diazotrophs [dinitrogen (N2)-fixing microbes], which can fix high rates of N2. Whether corals benefit from this extrinsic nitrogen source is still under debate. Until now, N2 fixation rates have been indirectly estimated using the acetylene reduction assay, which does not permit assessment of the amount of nitrogen incorporated into the different compartments of the coral holobiont. In the present study, the (15)N2 technique was applied for the first time on three Red Sea coral species. Significant (15)N enrichment was measured in particles released by corals to the surrounding seawater. N2 fixation rates were species specific and as high as 1.6-2 ng N day(-1) l(-1). However, no significant enrichment was measured in the symbiotic dinoflagellates or the coral host tissues, suggesting that corals do not benefit from diazotrophic N2 fixation.}, }
@article {pmid25272328, year = {2014}, author = {Hardoim, CC and Costa, R}, title = {Microbial communities and bioactive compounds in marine sponges of the family irciniidae-a review.}, journal = {Marine drugs}, volume = {12}, number = {10}, pages = {5089-5122}, doi = {10.3390/md12105089}, pmid = {25272328}, issn = {1660-3397}, mesh = {Animals ; Archaea/physiology ; Bacteria/metabolism ; Fungi/physiology ; Humans ; Porifera/*microbiology ; Quorum Sensing/*physiology ; Symbiosis/*physiology ; }, abstract = {Marine sponges harbour complex microbial communities of ecological and biotechnological importance. Here, we propose the application of the widespread sponge family Irciniidae as an appropriate model in microbiology and biochemistry research. Half a gram of one Irciniidae specimen hosts hundreds of bacterial species-the vast majority of which are difficult to cultivate-and dozens of fungal and archaeal species. The structure of these symbiont assemblages is shaped by the sponge host and is highly stable over space and time. Two types of quorum-sensing molecules have been detected in these animals, hinting at microbe-microbe and host-microbe signalling being important processes governing the dynamics of the Irciniidae holobiont. Irciniids are vulnerable to disease outbreaks, and concerns have emerged about their conservation in a changing climate. They are nevertheless amenable to mariculture and laboratory maintenance, being attractive targets for metabolite harvesting and experimental biology endeavours. Several bioactive terpenoids and polyketides have been retrieved from Irciniidae sponges, but the actual producer (host or symbiont) of these compounds has rarely been clarified. To tackle this, and further pertinent questions concerning the functioning, resilience and physiology of these organisms, truly multi-layered approaches integrating cutting-edge microbiology, biochemistry, genetics and zoology research are needed.}, }
@article {pmid25213651, year = {2015}, author = {Fernando, SC and Wang, J and Sparling, K and Garcia, GD and Francini-Filho, RB and de Moura, RL and Paranhos, R and Thompson, FL and Thompson, JR}, title = {Microbiota of the major South Atlantic reef building coral Mussismilia.}, journal = {Microbial ecology}, volume = {69}, number = {2}, pages = {267-280}, doi = {10.1007/s00248-014-0474-6}, pmid = {25213651}, issn = {1432-184X}, support = {P30-ES002109/ES/NIEHS NIH HHS/United States ; }, mesh = {Animals ; Anthozoa/*microbiology ; Brazil ; Cloning, Molecular ; Coral Reefs ; DNA, Bacterial/genetics ; Gammaproteobacteria/classification/genetics/isolation &amp; purification ; Gene Library ; *Microbiota ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; }, abstract = {The Brazilian endemic scleractinian corals, genus Mussismilia, are among the main reef builders of the South Atlantic and are threatened by accelerating rates of disease. To better understand how holobiont microbial populations interact with corals during health and disease and to evaluate whether selective pressures in the holobiont or neutral assembly shape microbial composition, we have examined the microbiota structure of Mussismilia corals according to coral lineage, environment, and disease/health status. Microbiota of three Mussismilia species (Mussismilia harttii, Mussismilia hispida, and Mussismilia braziliensis) was compared using 16S rRNA pyrosequencing and clone library analysis of coral fragments. Analysis of biological triplicates per Mussismilia species and reef site allowed assessment of variability among Mussismilia species and between sites for M. braziliensis. From 173,487 V6 sequences, 6,733 coral- and 1,052 water-associated operational taxonomic units (OTUs) were observed. M. braziliensis microbiota was more similar across reefs than to other Mussismilia species microbiota from the same reef. Highly prevalent OTUs were more significantly structured by coral lineage and were enriched in Alpha- and Gammaproteobacteria. Bacterial OTUs from healthy corals were recovered from a M. braziliensis skeleton sample at twice the frequency of recovery from water or a diseased coral suggesting the skeleton is a significant habitat for microbial populations in the holobiont. Diseased corals were enriched with pathogens and opportunists (Vibrios, Bacteroidetes, Thalassomonas, and SRB). Our study examines for the first time intra- and inter-specific variability of microbiota across the genus Mussismilia. Changes in microbiota may be useful indicators of coral health and thus be a valuable tool for coral reef management and conservation.}, }
@article {pmid25205353, year = {2014}, author = {Bosch, TC and Adamska, M and Augustin, R and Domazet-Loso, T and Foret, S and Fraune, S and Funayama, N and Grasis, J and Hamada, M and Hatta, M and Hobmayer, B and Kawai, K and Klimovich, A and Manuel, M and Shinzato, C and Technau, U and Yum, S and Miller, DJ}, title = {How do environmental factors influence life cycles and development? An experimental framework for early-diverging metazoans.}, journal = {BioEssays : news and reviews in molecular, cellular and developmental biology}, volume = {36}, number = {12}, pages = {1185-1194}, doi = {10.1002/bies.201400065}, pmid = {25205353}, issn = {1521-1878}, support = {F32 AI098418/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; *Biological Evolution ; Cnidaria/classification/genetics/*growth &amp; development ; Ecosystem ; Extinction, Biological ; Gene Expression Regulation, Developmental ; *Gene-Environment Interaction ; Life Cycle Stages/*genetics ; Metamorphosis, Biological/genetics ; Phylogeny ; Porifera/classification/genetics/*growth &amp; development ; Signal Transduction ; }, abstract = {Ecological developmental biology (eco-devo) explores the mechanistic relationships between the processes of individual development and environmental factors. Recent studies imply that some of these relationships have deep evolutionary origins, and may even pre-date the divergences of the simplest extant animals, including cnidarians and sponges. Development of these early diverging metazoans is often sensitive to environmental factors, and these interactions occur in the context of conserved signaling pathways and mechanisms of tissue homeostasis whose detailed molecular logic remain elusive. Efficient methods for transgenesis in cnidarians together with the ease of experimental manipulation in cnidarians and sponges make them ideal models for understanding causal relationships between environmental factors and developmental mechanisms. Here, we identify major questions at the interface between animal evolution and development and outline a road map for research aimed at identifying the mechanisms that link environmental factors to developmental mechanisms in early diverging metazoans. Also watch the Video Abstract.}, }
@article {pmid25202306, year = {2014}, author = {Parkinson, JE and Baums, IB}, title = {The extended phenotypes of marine symbioses: ecological and evolutionary consequences of intraspecific genetic diversity in coral-algal associations.}, journal = {Frontiers in microbiology}, volume = {5}, number = {}, pages = {445}, doi = {10.3389/fmicb.2014.00445}, pmid = {25202306}, issn = {1664-302X}, abstract = {Reef-building corals owe much of their success to a symbiosis with dinoflagellate microalgae in the genus Symbiodinium. In this association, the performance of each organism is tied to that of its partner, and together the partners form a holobiont that can be subject to selection. Climate change affects coral reefs, which are declining globally as a result. Yet the extent to which coral holobionts will be able to acclimate or evolve to handle climate change and other stressors remains unclear. Selection acts on individuals and evidence from terrestrial systems demonstrates that intraspecific genetic diversity plays a significant role in symbiosis ecology and evolution. However, we have a limited understanding of the effects of such diversity in corals. As molecular methods have advanced, so too has our recognition of the taxonomic and functional diversity of holobiont partners. Resolving the major components of the holobiont to the level of the individual will help us assess the importance of intraspecific diversity and partner interactions in coral-algal symbioses. Here, we hypothesize that unique combinations of coral and algal individuals yield functional diversity that affects not only the ecology and evolution of the coral holobiont, but associated communities as well. Our synthesis is derived from reviewing existing evidence and presenting novel data. By incorporating the effects of holobiont extended phenotypes into predictive models, we may refine our understanding of the evolutionary trajectory of corals and reef communities responding to climate change.}, }
@article {pmid25202301, year = {2014}, author = {Roth, MS}, title = {The engine of the reef: photobiology of the coral-algal symbiosis.}, journal = {Frontiers in microbiology}, volume = {5}, number = {}, pages = {422}, doi = {10.3389/fmicb.2014.00422}, pmid = {25202301}, issn = {1664-302X}, abstract = {Coral reef ecosystems thrive in tropical oligotrophic oceans because of the relationship between corals and endosymbiotic dinoflagellate algae called Symbiodinium. Symbiodinium convert sunlight and carbon dioxide into organic carbon and oxygen to fuel coral growth and calcification, creating habitat for these diverse and productive ecosystems. Light is thus a key regulating factor shaping the productivity, physiology, and ecology of the coral holobiont. Similar to all oxygenic photoautotrophs, Symbiodinium must safely harvest sunlight for photosynthesis and dissipate excess energy to prevent oxidative stress. Oxidative stress is caused by environmental stressors such as those associated with global climate change, and ultimately leads to breakdown of the coral-algal symbiosis known as coral bleaching. Recently, large-scale coral bleaching events have become pervasive and frequent threatening and endangering coral reefs. Because the coral-algal symbiosis is the biological engine producing the reef, the future of coral reef ecosystems depends on the ecophysiology of the symbiosis. This review examines the photobiology of the coral-algal symbiosis with particular focus on the photophysiological responses and timescales of corals and Symbiodinium. Additionally, this review summarizes the light environment and its dynamics, the vulnerability of the symbiosis to oxidative stress, the abiotic and biotic factors influencing photosynthesis, the diversity of the coral-algal symbiosis, and recent advances in the field. Studies integrating physiology with the developing &quot;omics&quot; fields will provide new insights into the coral-algal symbiosis. Greater physiological and ecological understanding of the coral-algal symbiosis is needed for protection and conservation of coral reefs.}, }
@article {pmid25199498, year = {2014}, author = {Pillai, P and Gouhier, TC and Vollmer, SV}, title = {The cryptic role of biodiversity in the emergence of host-microbial mutualisms.}, journal = {Ecology letters}, volume = {17}, number = {11}, pages = {1437-1446}, doi = {10.1111/ele.12349}, pmid = {25199498}, issn = {1461-0248}, mesh = {*Biodiversity ; Ecosystem ; Genetic Fitness ; Microbiota ; *Models, Biological ; *Symbiosis ; }, abstract = {The persistence of mutualisms in host-microbial - or holobiont - systems is difficult to explain because microbial mutualists, who bear the costs of providing benefits to their host, are always prone to being competitively displaced by non-mutualist 'cheater' species. This disruptive effect of competition is expected to be particularly strong when the benefits provided by the mutualists entail costs such as reduced competitive ability. Using a metacommunity model, we show that competition between multiple cheaters within the host's microbiome, when combined with the spatial structure of host-microbial interactions, can have a constructive rather than a disruptive effect by allowing the emergence and maintenance of mutualistic microorganisms within the host. These results indicate that many of the microorganisms inhabiting a host's microbiome, including those that would otherwise be considered opportunistic or even potential pathogens, play a cryptic yet critical role in promoting the health and persistence of the holobiont across spatial scales.}, }
@article {pmid25191338, year = {2014}, author = {Gilbert, SF}, title = {A holobiont birth narrative: the epigenetic transmission of the human microbiome.}, journal = {Frontiers in genetics}, volume = {5}, number = {}, pages = {282}, doi = {10.3389/fgene.2014.00282}, pmid = {25191338}, issn = {1664-8021}, abstract = {This essay plans to explore, expand, and re-tell the human birth narrative. Usually, human birth narratives focus on the origins of a new individual, focusing on the mother and fetus. This essay discusses birth as the origin of a new community. For not only is the eukaryotic body being reproduced, but so also are the bodies of its symbiotic microbes and so is the set of relationships between these organic components. Several parts of the new narrative are surprising: (1) bacterial symbionts might cause some of the characteristics of pregnancy and prepare a symbiotic community for transfer; (2) the first bacterial colonizers of the mammalian organism my enter the fetus prior to the lysing of the amniotic membrane and birth; (3) the same signals that often cause immunological attack against a microbe may serve under these conditions to signal homeostatic stability between symbiont and host; and (4) the mother may actively provide substances that promote the growth and settlement of helpful bacteria. The birth of the holobiont exemplifies principles of co-evolution, co-development, niche construction, and scaffolding. Birth is nothing less than the passage from one set of symbiotic relationships to another.}, }
@article {pmid25178787, year = {2014}, author = {Watson, J and Degnan, B and Degnan, S and Krömer, JO}, title = {Determining the biomass composition of a sponge holobiont for flux analysis.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1191}, number = {}, pages = {107-125}, doi = {10.1007/978-1-4939-1170-7_7}, pmid = {25178787}, issn = {1940-6029}, mesh = {Animals ; Biomass ; Bisbenzimidazole ; DNA/*analysis ; Fluorometry/methods ; Metabolic Flux Analysis/*methods ; *Models, Biological ; Porifera/anatomy &amp; histology/growth &amp; development/*metabolism/*microbiology ; Proteins/analysis ; Species Specificity ; *Symbiosis ; }, abstract = {The first step on the path of flux analysis of a new organism with little available literature is the determination of the biomass composition. Once the content of the macromolecular components (protein, RNA, DNA, carbohydrates, lipids) and their composition is known, this composition can be converted into a biomass equation. The biomass equation is an important part of metabolic flux analysis. This equation provides the information about the precursor and energy needs for growth. In many experiments the determination of the growth rate is the simplest flux to be determined, yet this rate determines the net fluxes of a whole range of anabolic pathways in the system and often is used as the objective function in FBA analysis. The challenge for the scientist is to create a biomass equation that represents the organisms of choice under the conditions studied. This chapter outlines basic protocols that can be applied to the quantification of the macromolecular components, using the marine demosponge Amphimedon queenslandica as a case study. As is true for all other sponges and indeed marine animals, A. queenslandica is a holobiont, comprising an animal host plus symbiotic and other associated microbial cells. We show how this complexity can be overcome by developing a fast, yet robust, method for biomass quantification of sponges using the displacement volume. The analytical protocols we describe herein are widely applicable not only to other organisms sampled from complex environments but also to cell cultures. The second part of the chapter highlights the procedures needed to convert a macromolecular composition into a biomass equation.}, }
@article {pmid25171444, year = {2015}, author = {Bettarel, Y and Bouvier, T and Nguyen, HK and Thu, PT}, title = {The versatile nature of coral-associated viruses.}, journal = {Environmental microbiology}, volume = {17}, number = {10}, pages = {3433-3439}, doi = {10.1111/1462-2920.12579}, pmid = {25171444}, issn = {1462-2920}, mesh = {Animals ; Anthozoa/microbiology/*virology ; Bacteria/*virology ; Bacteriophages/growth &amp; development ; Coral Reefs ; Dinoflagellida/*virology ; Phycodnaviridae/*growth &amp; development ; }, abstract = {A recent hypothesis considers that many coral pathologies are the result of a sudden structural alteration of the epibiotic bacterial communities in response to environmental disturbances. However, the ecological mechanisms that lead to shifts in their composition are still unclear. In the ocean, viruses represent a major bactericidal agent but little is known on their occurrence within the coral holobiont. Recent reports have revealed that viruses are abundant and diversified within the coral mucus and therefore could be decisive for coral health. However, their mode of action is still unknown, and there is now an urgent need to shed light on the nature of the relationships they might have with the other prokaryotic and eukaryotic members of the holobiont. In this opinion letter, we are putting forward the hypothesis that coral-associated viruses (mostly bacterial and algal viruses), depending on the environmental conditions might either reinforce coral stability or conversely fasten their decline. We propose that these processes are presumably based on an environmentally driven shift in infection strategies allowing viruses to regulate, circumstantially, both coral symbionts (bacteria or Symbiodinium) and surrounding pathogens.}, }
@article {pmid25156176, year = {2014}, author = {Lema, KA and Bourne, DG and Willis, BL}, title = {Onset and establishment of diazotrophs and other bacterial associates in the early life history stages of the coral Acropora millepora.}, journal = {Molecular ecology}, volume = {23}, number = {19}, pages = {4682-4695}, doi = {10.1111/mec.12899}, pmid = {25156176}, issn = {1365-294X}, mesh = {Animals ; Anthozoa/growth &amp; development/*microbiology ; Bacteria/*classification/genetics ; Genes, Bacterial ; Life Cycle Stages ; Molecular Sequence Data ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; *Symbiosis ; }, abstract = {Early establishment of coral-microbial symbioses is fundamental to the fitness of corals, but comparatively little is known about the onset and succession of bacterial communities in their early life history stages. In this study, bacterial associates of the coral Acropora millepora were characterized throughout the first year of life, from larvae and 1-week-old juveniles reared in laboratory conditions in the absence of the dinoflagellate endosymbiont Symbiodinium to field-outplanted juveniles with established Symbiodinium symbioses, and sampled at 2 weeks and at 3, 6 and 12 months. Using an amplicon pyrosequencing approach, the diversity of both nitrogen-fixing bacteria and of bacterial communities overall was assessed through analysis of nifH and 16S rRNA genes, respectively. The consistent presence of sequences affiliated with diazotrophs of the order Rhizobiales (23-58% of retrieved nifH sequences; 2-12% of 16S rRNA sequences), across all samples from larvae to 12-month-old coral juveniles, highlights the likely functional importance of this nitrogen-fixing order to the coral holobiont. Dominance of Roseobacter-affiliated sequences (>55% of retrieved 16S rRNA sequences) in larvae and 1-week-old juveniles, and the consistent presence of sequences related to Oceanospirillales and Altermonadales throughout all early life history stages, signifies their potential importance as coral associates. Increased diversity of bacterial communities once juveniles were transferred to the field, particularly of Cyanobacteria and Deltaproteobacteria, demonstrates horizontal (environmental) uptake of coral-associated bacterial communities. Although overall bacterial communities were dynamic, bacteria with likely important functional roles remain stable throughout early life stages of Acropora millepora.}, }
@article {pmid25120558, year = {2014}, author = {Dittami, SM and Barbeyron, T and Boyen, C and Cambefort, J and Collet, G and Delage, L and Gobet, A and Groisillier, A and Leblanc, C and Michel, G and Scornet, D and Siegel, A and Tapia, JE and Tonon, T}, title = {Genome and metabolic network of &quot;Candidatus Phaeomarinobacter ectocarpi&quot; Ec32, a new candidate genus of Alphaproteobacteria frequently associated with brown algae.}, journal = {Frontiers in genetics}, volume = {5}, number = {}, pages = {241}, doi = {10.3389/fgene.2014.00241}, pmid = {25120558}, issn = {1664-8021}, abstract = {Rhizobiales and related orders of Alphaproteobacteria comprise several genera of nodule-inducing symbiotic bacteria associated with plant roots. Here we describe the genome and the metabolic network of &quot;Candidatus Phaeomarinobacter ectocarpi&quot; Ec32, a member of a new candidate genus closely related to Rhizobiales and found in association with cultures of the filamentous brown algal model Ectocarpus. The &quot;Ca. P. ectocarpi&quot; genome encodes numerous metabolic pathways that may be relevant for this bacterium to interact with algae. Notably, it possesses a large set of glycoside hydrolases and transporters, which may serve to process and assimilate algal metabolites. It also harbors several proteins likely to be involved in the synthesis of algal hormones such as auxins and cytokinins, as well as the vitamins pyridoxine, biotin, and thiamine. As of today, &quot;Ca. P. ectocarpi&quot; has not been successfully cultured, and identical 16S rDNA sequences have been found exclusively associated with Ectocarpus. However, related sequences (≥97% identity) have also been detected free-living and in a Fucus vesiculosus microbiome barcoding project, indicating that the candidate genus &quot;Phaeomarinobacter&quot; may comprise several species, which may colonize different niches.}, }
@article {pmid25117532, year = {2015}, author = {Davis, TS}, title = {The ecology of yeasts in the bark beetle holobiont: a century of research revisited.}, journal = {Microbial ecology}, volume = {69}, number = {4}, pages = {723-732}, doi = {10.1007/s00248-014-0479-1}, pmid = {25117532}, issn = {1432-184X}, mesh = {Animals ; Larva/growth &amp; development/microbiology ; Ovum/growth &amp; development/microbiology ; Pheromones/physiology ; Pupa/growth &amp; development/microbiology ; *Symbiosis ; Weevils/growth &amp; development/*microbiology ; Yeasts/*physiology ; }, abstract = {Yeasts are extremely common associates of scolytine bark beetles, yet the basic ecology of yeasts in the bark beetle holobiont remains poorly understood. Yeasts are present in all beetle life stages and consistently isolated from adult, larval, and pupal integuments and mycangial structures, but yeasts are also found in oviposition galleries, pupal chambers, larval and adult digestive tracts, as well as phloem and xylem tissues. Yeasts in the Saccharomycetaceae family are the most prevalent associates, and most individual beetles are associated with only one or several yeast species. Kuraishia capsulata and Ogataea pini are the most commonly encountered yeast species in surveys of Dendroctonus and Ips beetles; most beetles that have been surveyed are vectors for one or both yeasts. Yeasts have significant but often overlooked functional roles in bark beetle ecology. Infochemicals resulting from volatile production by yeast have wide-ranging bioactivity for arthropods: Yeast emissions attract beetles at low concentrations but repel beetles at high concentrations, and yeast emissions can also serve as cues to predators and parasites of bark beetles. In some cases, yeasts can modify tree chemistry over time or metabolize toxic terpenoids, though potential consequences for beetle performance or the growth of nutritional fungi remain to be demonstrated. Also, the presence of yeast species can restrict or promote the establishment and growth of filamentous fungi, including mutualists, entomopathogens, and opportunistic saprophytes. The role of yeasts as nutritional symbionts has received mixed support, though a nutritional hypothesis has not been extensively tested. Continued research on the functional ecology of bark beetle-yeast associations is needed to better understand the emergent properties of these complex symbiont assemblages.}, }
@article {pmid25071729, year = {2014}, author = {Zchori-Fein, E and Lahav, T and Freilich, S}, title = {Variations in the identity and complexity of endosymbiont combinations in whitefly hosts.}, journal = {Frontiers in microbiology}, volume = {5}, number = {}, pages = {310}, doi = {10.3389/fmicb.2014.00310}, pmid = {25071729}, issn = {1664-302X}, abstract = {The target of natural selection is suggested to be the holobiont - the organism together with its associated symbiotic microorganisms. The well-defined endosymbiotic communities of insects make them a useful model for exploring the role of symbiotic interactions in shaping the functional repertoire of plants and animals. Here, we studied the variations in the symbiotic communities of the sweet potato whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) by compiling a dataset of over 2000 individuals derived from several independent screenings. The secondary endosymbionts harbored by each individual were clustered into entities termed Facultative Endosymbiont Combinations (FECs), each representing a natural assemblage of co-occurring bacterial genera. The association of FECs with whitefly individuals stratified the otherwise homogeneous population into holobiont units. We both identified bacterial assemblages that are specific to whitefly groups sharing unique genetic backgrounds, and characterized the FEC variations within these groups. The analysis revealed that FEC complexity is positively correlated with both distance from the equator and specificity of the genetic clade of the host insect. These findings highlight the importance of symbiotic combinations in shaping the distribution patterns of B. tabaci and possibly other insect species.}, }
@article {pmid25070863, year = {2014}, author = {Doo, SS and Fujita, K and Byrne, M and Uthicke, S}, title = {Fate of calcifying tropical symbiont-bearing large benthic foraminifera: living sands in a changing ocean.}, journal = {The Biological bulletin}, volume = {226}, number = {3}, pages = {169-186}, doi = {10.1086/BBLv226n3p169}, pmid = {25070863}, issn = {1939-8697}, mesh = {Animals ; Calcification, Physiologic ; Climate Change ; Coral Reefs ; Foraminifera/*physiology ; Geologic Sediments ; Oceans and Seas ; *Symbiosis ; Tropical Climate ; }, abstract = {Concerns regarding the response of calcifiers in future warmer and more acidic oceans have been raised in many studies. Tropical large benthic foraminifera (LBF) are important carbonate producers that reside in coral reefs worldwide. Similar to corals, these organisms live in symbioses with microalgae, which promote high calcification rates. The contribution of LBFs to reef sediments is under threat due to climate change. In this review, we synthesize research conducted on the effects of increased temperature and acidification on these organisms, and assess the potential impacts on reef carbonate production. A meta-analysis of all available experimental data (18 publications, 84 individual experiments) on the effects of ocean warming and acidification on LBF holobiont health was performed using log-transformed response ratios (LnRR) comparing present-day ambient and projected future scenarios. For the latter, we used Representative Concentration Pathway 8.5 from the Intergovernmental Panel on Climate Change, which projects changes of +4 °C and -0.3 pH units by the year 2100. Overall, a general negative trend on holobiont growth was observed across most species of LBFs in response to both stressors. The only exception was the hyaline species (porous CaCO3 test composed of interlocking microcrystals) that have diatom symbionts. Species in this group appear resilient to future ocean acidification scenarios. Differences in the response of LBF species to warming and acidifying oceans may be due to (1) differences in the carbonate species' use in formation of the CaCO3 skeleton (CO2 vs. CO3(2-)), (2) varied responses of the symbiont types (diatom, dinoflagellate, rhodophyte) to stressors, or (3) the degree of nutritional dependence of the host to its symbiont. We also summarize current estimates of carbonate production by LBFs to provide a context of their contribution to reefs. Finally, we outline major gaps in knowledge in addressing the potential for LBF species persistence in a changing ocean.}, }
@article {pmid25058318, year = {2014}, author = {Moree, WJ and McConnell, OJ and Nguyen, DD and Sanchez, LM and Yang, YL and Zhao, X and Liu, WT and Boudreau, PD and Srinivasan, J and Atencio, L and Ballesteros, J and Gavilán, RG and Torres-Mendoza, D and Guzmán, HM and Gerwick, WH and Gutiérrez, M and Dorrestein, PC}, title = {Microbiota of healthy corals are active against fungi in a light-dependent manner.}, journal = {ACS chemical biology}, volume = {9}, number = {10}, pages = {2300-2308}, doi = {10.1021/cb500432j}, pmid = {25058318}, issn = {1554-8937}, support = {TW006634/TW/FIC NIH HHS/United States ; S10 RR029121/RR/NCRR NIH HHS/United States ; S10RR029121/RR/NCRR NIH HHS/United States ; K12 GM068524/GM/NIGMS NIH HHS/United States ; U01 TW006634/TW/FIC NIH HHS/United States ; AI095125/AI/NIAID NIH HHS/United States ; }, mesh = {Animals ; Anthozoa/*microbiology ; Antifungal Agents/isolation &amp; purification/*pharmacology ; Fungi/*drug effects ; *Light ; *Microbiota ; Molecular Sequence Data ; Pseudoalteromonas/growth &amp; development/*isolation &amp; purification ; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization ; Symbiosis/*physiology ; }, abstract = {Coral reefs are intricate ecosystems that harbor diverse organisms, including 25% of all marine fish. Healthy corals exhibit a complex symbiosis between coral polyps, endosymbiotic alga, and an array of microorganisms, called the coral holobiont. Secretion of specialized metabolites by coral microbiota is thought to contribute to the defense of this sessile organism against harmful biotic and abiotic factors. While few causative agents of coral diseases have been unequivocally identified, fungi have been implicated in the massive destruction of some soft corals worldwide. Because corals are nocturnal feeders, they may be more vulnerable to fungal infection at night, and we hypothesized that the coral microbiota would have the capability to enhance their defenses against fungi in the dark. A Pseudoalteromonas sp. isolated from a healthy octocoral displayed light-dependent antifungal properties when grown adjacent to Penicillium citrinum (P. citrinum) isolated from a diseased Gorgonian octocoral. Microbial MALDI-imaging mass spectrometry (IMS) coupled with molecular network analyses revealed that Pseudoalteromonas produced higher levels of antifungal polyketide alteramides in the dark than in the light. The alteramides were inactivated by light through a photoinduced intramolecular cyclization. Further NMR studies led to a revision of the stereochemical structure of the alteramides. Alteramide A exhibited antifungal properties and elicited changes in fungal metabolite distributions of mycotoxin citrinin and citrinadins. These data support the hypothesis that coral microbiota use abiotic factors such as light to regulate the production of metabolites with specialized functions to combat opportunistic pathogens at night.}, }
@article {pmid25050199, year = {2014}, author = {Erdman, SE and Poutahidis, T}, title = {The microbiome modulates the tumor macroenvironment.}, journal = {Oncoimmunology}, volume = {3}, number = {}, pages = {e28271}, doi = {10.4161/onci.28271}, pmid = {25050199}, issn = {2162-4011}, support = {P30 ES002109/ES/NIEHS NIH HHS/United States ; U01 CA164337/CA/NCI NIH HHS/United States ; }, abstract = {Earlier investigations of the tumor microenvironment unveiled systemic networks presenting novel therapeutic opportunities. It has been recently shown that gut microbes modulate whole host immune and neuroendocrine factors impacting the fate of distant preneoplastic lesions toward malignancy or regression. These findings establish a new paradigm of holobiont therapeutic engineering in emerging tumor macroenvironments.}, }
@article {pmid25044878, year = {2014}, author = {Grottoli, AG and Warner, ME and Levas, SJ and Aschaffenburg, MD and Schoepf, V and McGinley, M and Baumann, J and Matsui, Y}, title = {The cumulative impact of annual coral bleaching can turn some coral species winners into losers.}, journal = {Global change biology}, volume = {20}, number = {12}, pages = {3823-3833}, doi = {10.1111/gcb.12658}, pmid = {25044878}, issn = {1365-2486}, mesh = {Acclimatization/*physiology ; Analysis of Variance ; Animals ; Anthozoa/*microbiology/*physiology ; Caribbean Region ; Dinoflagellida/*physiology ; Photosynthesis/physiology ; Species Specificity ; Stress, Physiological/*physiology ; *Symbiosis ; *Temperature ; }, abstract = {Mass coral bleaching events caused by elevated seawater temperatures result in extensive coral loss throughout the tropics, and are projected to increase in frequency and severity. If bleaching becomes an annual event later in this century, more than 90% of coral reefs worldwide may be at risk of long-term degradation. While corals can recover from single isolated bleaching and can acclimate to recurring bleaching events that are separated by multiple years, it is currently unknown if and how they will survive and possibly acclimatize to annual coral bleaching. Here, we demonstrate for the first time that annual coral bleaching can dramatically alter thermal tolerance in Caribbean corals. We found that high coral energy reserves and changes in the dominant algal endosymbiont type (Symbiodinium spp.) facilitated rapid acclimation in Porites divaricata, whereas low energy reserves and a lack of algal phenotypic plasticity significantly increased susceptibility in Porites astreoides to bleaching the following year. Phenotypic plasticity in the dominant endosymbiont type of Orbicella faveolata did not prevent repeat bleaching, but may have facilitated rapid recovery. Thus, coral holobiont response to an isolated single bleaching event is not an accurate predictor of its response to bleaching the following year. Rather, the cumulative impact of annual coral bleaching can turn some coral species 'winners' into 'losers', and can also facilitate acclimation and turn some coral species 'losers' into 'winners'. Overall, these findings indicate that cumulative impact of annual coral bleaching could result in some species becoming increasingly susceptible to bleaching and face a long-term decline, while phenotypically plastic coral species will acclimatize and persist. Thus, annual coral bleaching and recovery could contribute to the selective loss of coral diversity as well as the overall decline of coral reefs in the Caribbean.}, }
@article {pmid25016412, year = {2014}, author = {Gust, KA and Najar, FZ and Habib, T and Lotufo, GR and Piggot, AM and Fouke, BW and Laird, JG and Wilbanks, MS and Rawat, A and Indest, KJ and Roe, BA and Perkins, EJ}, title = {Coral-zooxanthellae meta-transcriptomics reveals integrated response to pollutant stress.}, journal = {BMC genomics}, volume = {15}, number = {}, pages = {591}, doi = {10.1186/1471-2164-15-591}, pmid = {25016412}, issn = {1471-2164}, mesh = {Animals ; Anthozoa/drug effects/*genetics/metabolism ; Dinoflagellida/drug effects/*genetics/metabolism ; Molecular Sequence Annotation ; Oligonucleotide Array Sequence Analysis ; Stress, Physiological ; Symbiosis ; Transcriptome/*drug effects ; Triazines/*pharmacology ; Water Pollutants, Chemical/*pharmacology ; }, abstract = {BACKGROUND: Corals represent symbiotic meta-organisms that require harmonization among the coral animal, photosynthetic zooxanthellae and associated microbes to survive environmental stresses. We investigated integrated-responses among coral and zooxanthellae in the scleractinian coral Acropora formosa in response to an emerging marine pollutant, the munitions constituent, 1,3,5-trinitro-1,3,5 triazine (RDX; 5 day exposures to 0 (control), 0.5, 0.9, 1.8, 3.7, and 7.2 mg/L, measured in seawater).<br><br>RESULTS: RDX accumulated readily in coral soft tissues with bioconcentration factors ranging from 1.1 to 1.5. Next-generation sequencing of a normalized meta-transcriptomic library developed for the eukaryotic components of the A. formosa coral holobiont was leveraged to conduct microarray-based global transcript expression analysis of integrated coral/zooxanthellae responses to the RDX exposure. Total differentially expressed transcripts (DET) increased with increasing RDX exposure concentrations as did the proportion of zooxanthellae DET relative to the coral animal. Transcriptional responses in the coral demonstrated higher sensitivity to RDX compared to zooxanthellae where increased expression of gene transcripts coding xenobiotic detoxification mechanisms (i.e. cytochrome P450 and UDP glucuronosyltransferase 2 family) were initiated at the lowest exposure concentration. Increased expression of these detoxification mechanisms was sustained at higher RDX concentrations as well as production of a physical barrier to exposure through a 40% increase in mucocyte density at the maximum RDX exposure. At and above the 1.8 mg/L exposure concentration, DET coding for genes involved in central energy metabolism, including photosynthesis, glycolysis and electron-transport functions, were decreased in zooxanthellae although preliminary data indicated that zooxanthellae densities were not affected. In contrast, significantly increased transcript expression for genes involved in cellular energy production including glycolysis and electron-transport pathways was observed in the coral animal.<br><br>CONCLUSIONS: Transcriptional network analysis for central energy metabolism demonstrated highly correlated responses to RDX among the coral animal and zooxanthellae indicative of potential compensatory responses to lost photosynthetic potential within the holobiont. These observations underscore the potential for complex integrated responses to RDX exposure among species comprising the coral holobiont and highlight the need to understand holobiont-species interactions to accurately assess pollutant impacts.}, }
@article {pmid24995875, year = {2014}, author = {McFall-Ngai, MJ}, title = {The importance of microbes in animal development: lessons from the squid-vibrio symbiosis.}, journal = {Annual review of microbiology}, volume = {68}, number = {}, pages = {177-194}, doi = {10.1146/annurev-micro-091313-103654}, pmid = {24995875}, issn = {1545-3251}, mesh = {Animals ; Decapodiformes/*growth &amp; development/*microbiology/physiology ; *Symbiosis ; Vibrio/*physiology ; }, abstract = {Developmental biology is among the many subdisciplines of the life sciences being transformed by our increasing awareness of the role of coevolved microbial symbionts in health and disease. Most symbioses are horizontally acquired, i.e., they begin anew each generation. In such associations, the embryonic period prepares the animal to engage with the coevolved partner(s) with fidelity following birth or hatching. Once interactions are underway, the microbial partners drive maturation of tissues that are either directly associated with or distant from the symbiont populations. Animal alliances often involve complex microbial communities, such as those in the vertebrate gastrointestinal tract. A series of simpler-model systems is providing insight into the basic rules and principles that govern the establishment and maintenance of stable animal-microbe partnerships. This review focuses on what biologists have learned about the developmental trajectory of horizontally acquired symbioses through the study of the binary squid-vibrio model.}, }
@article {pmid24992663, year = {2014}, author = {Dheilly, NM}, title = {Holobiont-Holobiont interactions: redefining host-parasite interactions.}, journal = {PLoS pathogens}, volume = {10}, number = {7}, pages = {e1004093}, doi = {10.1371/journal.ppat.1004093}, pmid = {24992663}, issn = {1553-7374}, mesh = {Animals ; *Host-Pathogen Interactions ; Humans ; Plant Diseases ; Plants ; }, }
@article {pmid24982156, year = {2014}, author = {Kelly, LW and Williams, GJ and Barott, KL and Carlson, CA and Dinsdale, EA and Edwards, RA and Haas, AF and Haynes, M and Lim, YW and McDole, T and Nelson, CE and Sala, E and Sandin, SA and Smith, JE and Vermeij, MJ and Youle, M and Rohwer, F}, title = {Local genomic adaptation of coral reef-associated microbiomes to gradients of natural variability and anthropogenic stressors.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {111}, number = {28}, pages = {10227-10232}, doi = {10.1073/pnas.1403319111}, pmid = {24982156}, issn = {1091-6490}, mesh = {*Adaptation, Physiological ; *Bacteria/genetics/metabolism ; *Coral Reefs ; *Gene Transfer, Horizontal ; *Metagenome ; *Microbiota ; Pacific Ocean ; *Water Pollution ; }, abstract = {Holobionts are species-specific associations between macro- and microorganisms. On coral reefs, the benthic coverage of coral and algal holobionts varies due to natural and anthropogenic forcings. Different benthic macroorganisms are predicted to have specific microbiomes. In contrast, local environmental factors are predicted to select for specific metabolic pathways in microbes. To reconcile these two predictions, we hypothesized that adaptation of microbiomes to local conditions is facilitated by the horizontal transfer of genes responsible for specific metabolic capabilities. To test this hypothesis, microbial metagenomes were sequenced from 22 coral reefs at 11 Line Islands in the central Pacific that together span a wide range of biogeochemical and anthropogenic influences. Consistent with our hypothesis, the percent cover of major benthic functional groups significantly correlated with particular microbial taxa. Reefs with higher coral cover had a coral microbiome with higher abundances of Alphaproteobacteria (such as Rhodobacterales and Sphingomonadales), whereas microbiomes of algae-dominated reefs had higher abundances of Gammaproteobacteria (such as Alteromonadales, Pseudomonadales, and Vibrionales), Betaproteobacteria, and Bacteriodetes. In contrast to taxa, geography was the strongest predictor of microbial community metabolism. Microbial communities on reefs with higher nutrient availability (e.g., equatorial upwelling zones) were enriched in genes involved in nutrient-related metabolisms (e.g., nitrate and nitrite ammonification, Ton/Tol transport, etc.). On reefs further from the equator, microbes had more genes encoding chlorophyll biosynthesis and photosystems I/II. These results support the hypothesis that core microbiomes are determined by holobiont macroorganisms, and that those core taxa adapt to local conditions by selecting for advantageous metabolic genes.}, }
@article {pmid24960461, year = {2014}, author = {Watson, JR and Brennan, TC and Degnan, BM and Degnan, SM and Krömer, JO}, title = {Analysis of the biomass composition of the demosponge Amphimedon queenslandica on Heron Island Reef, Australia.}, journal = {Marine drugs}, volume = {12}, number = {6}, pages = {3733-3753}, doi = {10.3390/md12063733}, pmid = {24960461}, issn = {1660-3397}, mesh = {Amino Acids/chemistry/isolation &amp; purification ; Animals ; Australia ; *Biomass ; Fatty Acids/chemistry/isolation &amp; purification ; Genome ; Genomics/*methods ; Models, Genetic ; Porifera/genetics/*metabolism ; }, abstract = {Marine sponges are a potential source of important pharmaceutical drugs, the commercialisation of which is restricted by the difficulties of obtaining a sufficient and regular supply of biomass. One way to optimize commercial cell lines for production is the in-depth characterization and target identification through genome scale metabolic modeling and flux analysis. By applying these tools to a sponge, we hope to gain insights into how biomass is formed. We chose Amphimedon queenslandica as it has an assembled and annotated genome, a prerequisite for genome scale modeling. The first stepping stone on the way to metabolic flux analysis in a sponge holobiont, is the characterization of its biomass composition. In this study we quantified the macromolecular composition and investigated the variation between and within sponges of a single population. We found lipids and protein to be the most abundant macromolecules, while carbohydrates were the most variable. We also analysed the composition and abundance of the fatty acids and amino acids, the important building blocks required to synthesise the abundant macromolecule types, lipids, and protein. These data complement the extensive genomic information available for A. queenslandica and lay the basis for genome scale modelling and flux analysis.}, }
@article {pmid24950107, year = {2014}, author = {Closek, CJ and Sunagawa, S and DeSalvo, MK and Piceno, YM and DeSantis, TZ and Brodie, EL and Weber, MX and Voolstra, CR and Andersen, GL and Medina, M}, title = {Coral transcriptome and bacterial community profiles reveal distinct Yellow Band Disease states in Orbicella faveolata.}, journal = {The ISME journal}, volume = {8}, number = {12}, pages = {2411-2422}, doi = {10.1038/ismej.2014.85}, pmid = {24950107}, issn = {1751-7370}, mesh = {Alveolata/classification/isolation &amp; purification ; Animals ; Anthozoa/*genetics/metabolism/*microbiology ; Bacteria/*classification/isolation &amp; purification ; *Transcriptome ; }, abstract = {Coral diseases impact reefs globally. Although we continue to describe diseases, little is known about the etiology or progression of even the most common cases. To examine a spectrum of coral health and determine factors of disease progression we examined Orbicella faveolata exhibiting signs of Yellow Band Disease (YBD), a widespread condition in the Caribbean. We used a novel combined approach to assess three members of the coral holobiont: the coral-host, associated Symbiodinium algae, and bacteria. We profiled three conditions: (1) healthy-appearing colonies (HH), (2) healthy-appearing tissue on diseased colonies (HD), and (3) diseased lesion (DD). Restriction fragment length polymorphism analysis revealed health state-specific diversity in Symbiodinium clade associations. 16S ribosomal RNA gene microarrays (PhyloChips) and O. faveolata complimentary DNA microarrays revealed the bacterial community structure and host transcriptional response, respectively. A distinct bacterial community structure marked each health state. Diseased samples were associated with two to three times more bacterial diversity. HD samples had the highest bacterial richness, which included components associated with HH and DD, as well as additional unique families. The host transcriptome under YBD revealed a reduced cellular expression of defense- and metabolism-related processes, while the neighboring HD condition exhibited an intermediate expression profile. Although HD tissue appeared visibly healthy, the microbial communities and gene expression profiles were distinct. HD should be regarded as an additional (intermediate) state of disease, which is important for understanding the progression of YBD.}, }
@article {pmid24860563, year = {2014}, author = {Luter, HM and Gibb, K and Webster, NS}, title = {Eutrophication has no short-term effect on the Cymbastela stipitata holobiont.}, journal = {Frontiers in microbiology}, volume = {5}, number = {}, pages = {216}, doi = {10.3389/fmicb.2014.00216}, pmid = {24860563}, issn = {1664-302X}, abstract = {Levels of nitrogen in coastal areas have been rapidly increasing due to accumulative inputs of sewage and terrigenous sediments carrying fertilizers. Sponges have an immense filtering capacity and may be directly impacted (positively or negatively) by elevated concentrations of nitrogen. Sponges also host a wide diversity of microbes involved in nitrogen metabolism, yet little is known about the effects of nitrogen loading on these symbiotic partnerships. Manipulative experiments were undertaken to examine the potential effects of excess nitrogen (up to 240 μM) on microbial symbiosis in the abundant sponge species Cymbastela stipitata. Microbial composition and activity were examined using 454-pyrotag sequencing of DNA- and RNA-derived samples. Despite the high levels of nitrogen exposure (up to 124-fold above ambient), sponges appeared visibly unaffected at all treatment concentrations. At the phylum level, the microbial community was consistent between all sponge samples regardless of nitrogen treatment, with Cyanobacteria and Thaumarchaeota being the dominant taxa. Higher microbial diversity was observed at the operational taxonomic units (OTU) level (97% sequence similarity), with only 40% of OTUs shared between samples from all treatments. However, a single cyanobacterial OTU dominated the community of all individuals (average 73.5%) and this OTU did not vary with nitrogen treatment. The conserved microbial community in all sponges irrespective of nitrogen treatment highlights the stability of the sponge-microbe relationship and indicates that the holobiont is resistant to short pulses of nitrogen at levels mimicking sewage effluent.}, }
@article {pmid24847321, year = {2014}, author = {Weynberg, KD and Wood-Charlson, EM and Suttle, CA and van Oppen, MJ}, title = {Generating viral metagenomes from the coral holobiont.}, journal = {Frontiers in microbiology}, volume = {5}, number = {}, pages = {206}, doi = {10.3389/fmicb.2014.00206}, pmid = {24847321}, issn = {1664-302X}, abstract = {Reef-building corals comprise multipartite symbioses where the cnidarian animal is host to an array of eukaryotic and prokaryotic organisms, and the viruses that infect them. These viruses are critical elements of the coral holobiont, serving not only as agents of mortality, but also as potential vectors for lateral gene flow, and as elements encoding a variety of auxiliary metabolic functions. Consequently, understanding the functioning and health of the coral holobiont requires detailed knowledge of the associated viral assemblage and its function. Currently, the most tractable way of uncovering viral diversity and function is through metagenomic approaches, which is inherently difficult in corals because of the complex holobiont community, an extracellular mucus layer that all corals secrete, and the variety of sizes and structures of nucleic acids found in viruses. Here we present the first protocol for isolating, purifying and amplifying viral nucleic acids from corals based on mechanical disruption of cells. This method produces at least 50% higher yields of viral nucleic acids, has very low levels of cellular sequence contamination and captures wider viral diversity than previously used chemical-based extraction methods. We demonstrate that our mechanical-based method profiles a greater diversity of DNA and RNA genomes, including virus groups such as Retro-transcribing and ssRNA viruses, which are absent from metagenomes generated via chemical-based methods. In addition, we briefly present (and make publically available) the first paired DNA and RNA viral metagenomes from the coral Acropora tenuis.}, }
@article {pmid24814756, year = {2014}, author = {Hardoim, CC and Costa, R}, title = {Temporal dynamics of prokaryotic communities in the marine sponge Sarcotragus spinosulus.}, journal = {Molecular ecology}, volume = {23}, number = {12}, pages = {3097-3112}, doi = {10.1111/mec.12789}, pmid = {24814756}, issn = {1365-294X}, mesh = {Animals ; Archaea/*classification/genetics ; Bacteria/*classification/genetics ; DNA, Archaeal/genetics ; DNA, Bacterial/genetics ; *Microbiota ; Molecular Sequence Data ; Phylogeny ; Porifera/genetics/*microbiology ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Symbiosis ; }, abstract = {In spite of their putative relevance to host functioning, in-depth knowledge of sponge microbiome stability over time is scarce. This study tackles the temporal maintenance of bacterial and archaeal assemblages in the model host Sarcotragus spinosulus along three successive years. Prokaryotic communities were profiled by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and 454-pyrosequencing of S. spinosulus-derived 16S rRNA gene amplicons. Prevailing bacterial phyla were Actinobacteria, Acidobacteria, Proteobacteria, Poribacteria, PAUC34f, Chloroflexi and Bacteroidetes, with Bacteroidetes, Chloroflexi and Poribacteria showing different abundances over the years. At the approximate species level (operational taxonomic units, OTUs, defined at 97% sequence similarity), no major changes in bacterial richness and composition were found through time. Nearly 50% of all detected bacterial symbionts (96 in 205 OTUs) were recovered from all sampling years, whereas a taxonomically equivalent community of less dominant bacteria characterized the transient sponge microbiota. Despite the evidence for temporal symbiont maintenance, an intriguing cumulative degree of variation between individuals was unravelled, with all the surveyed sponge specimens sharing only 27 bacterial OTUs. Archaeal communities were dominated by one single symbiont of the candidate genus Nitrosopumilus (Thaumarchaeota), known for its ability to aerobically oxidize ammonia to nitrite. Only few bacterial ammonia oxidizers consistently occurred in S. spinosulus across the years as documented by PCR-DGGE fingerprinting. In conclusion, prokaryotic symbionts of S. spinosulus display a state of dynamic stability shaped by the interplay between the maintenance of dominant players and turnover of less prevalent community members, in time and across host individuals, with no apparent consequences to holobiont functioning.}, }
@article {pmid24782852, year = {2014}, author = {Webster, NS}, title = {Cooperation, communication, and co-evolution: grand challenges in microbial symbiosis research.}, journal = {Frontiers in microbiology}, volume = {5}, number = {}, pages = {164}, doi = {10.3389/fmicb.2014.00164}, pmid = {24782852}, issn = {1664-302X}, }
@article {pmid24778636, year = {2014}, author = {Poutahidis, T and Kleinewietfeld, M and Erdman, SE}, title = {Gut microbiota and the paradox of cancer immunotherapy.}, journal = {Frontiers in immunology}, volume = {5}, number = {}, pages = {157}, doi = {10.3389/fimmu.2014.00157}, pmid = {24778636}, issn = {1664-3224}, support = {P30 ES002109/ES/NIEHS NIH HHS/United States ; R01 CA108854/CA/NCI NIH HHS/United States ; U01 CA164337/CA/NCI NIH HHS/United States ; }, abstract = {It is recently shown that beneficial environmental microbes stimulate integrated immune and neuroendocrine factors throughout the body, consequently modulating regulatory T-lymphocyte phenotypes, maintaining systemic immune balance, and determining the fate of preneoplastic lesions toward regression while sustaining whole body good health. Stimulated by a gut microbiota-centric systemic homeostasis hypothesis, we set out to explore the influence of the gut microbiome to explain the paradoxical roles of regulatory T-lymphocytes in cancer development and growth. This paradigm shift places cancer prevention and treatment into a new broader context of holobiont engineering to cultivate a tumor-suppressive macroenvironment.}, }
@article {pmid24769774, year = {2014}, author = {Rivest, EB and Hofmann, GE}, title = {Responses of the metabolism of the larvae of Pocillopora damicornis to ocean acidification and warming.}, journal = {PloS one}, volume = {9}, number = {4}, pages = {e96172}, doi = {10.1371/journal.pone.0096172}, pmid = {24769774}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*metabolism ; Carbon Dioxide/chemistry ; Citrate (si)-Synthase/metabolism ; Global Warming ; Hydrogen-Ion Concentration ; Larva/metabolism ; Oxygen Consumption ; Pacific Ocean ; Temperature ; }, abstract = {Ocean acidification and warming are expected to threaten the persistence of tropical coral reef ecosystems. As coral reefs face multiple stressors, the distribution and abundance of corals will depend on the successful dispersal and settlement of coral larvae under changing environmental conditions. To explore this scenario, we used metabolic rate, at holobiont and molecular levels, as an index for assessing the physiological plasticity of Pocillopora damicornis larvae from this site to conditions of ocean acidity and warming. Larvae were incubated for 6 hours in seawater containing combinations of CO2 concentration (450 and 950 µatm) and temperature (28 and 30°C). Rates of larval oxygen consumption were higher at elevated temperatures. In contrast, high CO2 levels elicited depressed metabolic rates, especially for larvae released later in the spawning period. Rates of citrate synthase, a rate-limiting enzyme in aerobic metabolism, suggested a biochemical limit for increasing oxidative capacity in coral larvae in a warming, acidifying ocean. Biological responses were also compared between larvae released from adult colonies on the same day (cohorts). The metabolic physiology of Pocillopora damicornis larvae varied significantly by day of release. Additionally, we used environmental data collected on a reef in Moorea, French Polynesia to provide information about what adult corals and larvae may currently experience in the field. An autonomous pH sensor provided a continuous time series of pH on the natal fringing reef. In February/March, 2011, pH values averaged 8.075 ± 0.023. Our results suggest that without adaptation or acclimatization, only a portion of naïve Pocillopora damicornis larvae may have suitable metabolic phenotypes for maintaining function and fitness in an end-of-the century ocean.}, }
@article {pmid24736967, year = {2014}, author = {Stazi, MA and Toccaceli, V}, title = {[Genome and microbiome: hologenome. Is epigenetics their link?].}, journal = {Epidemiologia e prevenzione}, volume = {38}, number = {1}, pages = {67-68}, pmid = {24736967}, issn = {1120-9763}, mesh = {Animals ; *Epigenomics ; Gene Transfer, Horizontal ; *Genome ; Germ-Free Life ; Humans ; Intestines/microbiology ; Mice ; MicroRNAs/genetics ; *Microbiota ; }, }
@article {pmid24736154, year = {2014}, author = {Gilbert, SF}, title = {Symbiosis as the way of eukaryotic life: the dependent co-origination of the body.}, journal = {Journal of biosciences}, volume = {39}, number = {2}, pages = {201-209}, pmid = {24736154}, issn = {0973-7138}, mesh = {Animals ; Biological Evolution ; Genetic Variation ; Humans ; Microbiota/immunology ; Selection, Genetic ; *Symbiosis ; }, abstract = {Molecular analyses of symbiotic relationships are challenging our biological definitions of individuality and supplanting them with a new notion of normal part-whole relationships. This new notion is that of a 'holobiont', a consortium of organisms that becomes a functionally integrated 'whole'. This holobiont includes the zoological organism (the 'animal') as well as its persistent microbial symbionts. This new individuality is seen on anatomical and physiological levels, where a diversity of symbionts form a new 'organ system' within the zoological organism and become integrated into its metabolism and development. Moreover, as in normal development, there are reciprocal interactions between the 'host' organism and its symbionts that alter gene expression in both sets of cells. The immune system, instead of being seen as functioning solely to keep microbes out of the body, is also found to develop, in part, in dialogue with symbionts. Moreover, the immune system is actively involved in the colonization of the zoological organism, functioning as a mechanism for integrating microbes into the animal-cell community. Symbionts have also been found to constitute a second mode of genetic inheritance, providing selectable genetic variation for natural selection. We develop, grow and evolve as multi-genomic consortia/teams/ecosystems.}, }
@article {pmid26988195, year = {2014}, author = {Probert, I and Siano, R and Poirier, C and Decelle, J and Biard, T and Tuji, A and Suzuki, N and Not, F}, title = {Brandtodinium gen. nov. and B. nutricula comb. Nov. (Dinophyceae), a dinoflagellate commonly found in symbiosis with polycystine radiolarians.}, journal = {Journal of phycology}, volume = {50}, number = {2}, pages = {388-399}, doi = {10.1111/jpy.12174}, pmid = {26988195}, issn = {1529-8817}, abstract = {Symbiotic interactions between pelagic hosts and microalgae have received little attention, although they are widespread in the photic layer of the world ocean, where they play a fundamental role in the ecology of the planktonic ecosystem. Polycystine radiolarians (including the orders Spumellaria, Collodaria and Nassellaria) are planktonic heterotrophic protists that are widely distributed and often abundant in the ocean. Many polycystines host symbiotic microalgae within their cytoplasm, mostly thought to be the dinoflagellate Scrippsiella nutricula, a species originally described by Karl Brandt in the late nineteenth century as Zooxanthella nutricula. The free-living stage of this dinoflagellate has never been characterized in terms of morphology and thecal plate tabulation. We examined morphological characters and sequenced conservative ribosomal markers of clonal cultures of the free-living stage of symbiotic dinoflagellates isolated from radiolarian hosts from the three polycystine orders. In addition, we sequenced symbiont genes directly from several polycystine-symbiont holobiont specimens from different oceanic regions. Thecal plate arrangement of the free-living stage does not match that of Scrippsiella or related genera, and LSU and SSU rDNA-based molecular phylogenies place these symbionts in a distinct clade within the Peridiniales. Both phylogenetic analyses and the comparison of morphological features of culture strains with those reported for other closely related species support the erection of a new genus that we name Brandtodinium gen. nov. and the recombination of S. nutricula as B. nutricula comb. nov.}, }
@article {pmid24594773, year = {2014}, author = {Fujita, K and Okai, T and Hosono, T}, title = {Oxygen metabolic responses of three species of large benthic foraminifers with algal symbionts to temperature stress.}, journal = {PloS one}, volume = {9}, number = {3}, pages = {e90304}, doi = {10.1371/journal.pone.0090304}, pmid = {24594773}, issn = {1932-6203}, mesh = {Climate Change ; Foraminifera/*metabolism/physiology ; Microalgae/*metabolism/physiology ; Oxygen/*metabolism ; *Stress, Physiological ; *Symbiosis ; *Temperature ; }, abstract = {Water temperature affects the physiology of large benthic foraminifers (LBFs) with algal symbionts dwelling in coral reef environments. However, the detailed physiological responses of LBF holobionts to temperature ranges occurring in their habitats are not known. We report net oxygen (O2) production and respiration rates of three LBF holobionts (Baculogypsina sphaerulata and Calcarina gaudichaudii hosting diatom symbionts, and Amphisorus kudakajimensis hosting dinoflagellate symbionts) measured in the laboratory at water temperatures ranging from 5°C to 45°C in 2.5°C or 5°C intervals and with light saturation levels of ∼500 µmol m(-2) s(-1). In addition, the recovery of net O2 production and respiration rates after exposure to temperature stress was assessed. The net O2 production and respiration rates of the three LBF holobionts peaked at ∼30°C, indicating their optimal temperature for a short exposure period. At extreme high temperatures (≥40°C), the net O2 production rates of all three LBF holobionts declined to less than zero and the respiration rates slightly decreased, indicating that photosynthesis of algal symbionts was inactivated. At extreme low temperatures (≤10°C for two calcarinid species and ≤5°C for A. kudakajimensis), the net O2 production and respiration rates were near zero, indicating a weakening of holobiont activity. After exposure to extreme high or low temperature, the net O2 production rates did not recover until the following day, whereas the respiration rates recovered rapidly, suggesting that a longer time (days) is required for recovery from damage to the photosystem by temperature stress compared to the respiration system. These results indicate that the oxygen metabolism of LBF holobionts can generally cope well with conditions that fluctuate diurnally and seasonally in their habitats. However, temporal heat and cold stresses with high light levels may induce severe damage to algal symbionts and also damage to host foraminifers.}, }
@article {pmid24568029, year = {2013}, author = {Guerrero, R and Margulis, L and Berlanga, M}, title = {Symbiogenesis: the holobiont as a unit of evolution.}, journal = {International microbiology : the official journal of the Spanish Society for Microbiology}, volume = {16}, number = {3}, pages = {133-143}, doi = {10.2436/20.1501.01.188}, pmid = {24568029}, issn = {1139-6709}, mesh = {Animals ; Bacteria/*genetics ; *Biological Evolution ; Insecta/*genetics/*microbiology/physiology ; *Microbiota ; Selection, Genetic ; *Symbiosis ; }, abstract = {Symbiogenesis is the result of the permanent coexistence of various bionts to form the holobiont (namely, the host and its microbiota). The holobiome is the sum total of the component genomes in a eukaryotic organism; it comprises the genome of an individual member of a given taxon (the host genome) and the microbiome (the genomes of the symbiotic microbiota). The latter is made up of the genes of a variety of microbial communities that persist over time and are not eliminated by natural selection. Therefore, the holobiome can also be considered as the genomic reflection of the complex network of symbiotic interactions that link an individual member of a given taxon with its associated microbiome. Eukaryotic individuals can be analyzed as coevolved, tightly integrated, prokaryotic communities; in this view, natural selection acts on the holobiont as if it were an integrated unit. The best studied holobionts are those that emerged from symbioses involving insects. The presence of symbiotic associations throughout most of the evolutionary history of insects suggests that they were a driving force in the diversification of this group. Support for the evolutionary importance of symbiogenesis comes from the observation that the gradual passage from an ancestral to a descendant species by the accumulation of random mutations has not been demonstrated in the field, nor in the laboratory, nor in the fossil record. Instead, symbiogenesis expands the view of the point-mutation-only as the unique mechanisms of evolution and offers an explanation for the discontinuities in the fossil record (&quot;punctuated equilibrium&quot;). As such, it challenges conventional paradigms in biology. This review describes the relationships between xylophagous insects and their microbiota in an attempt to understand the characteristics that have determined bacterial fidelity over generations and throughout evolutionary history.}, }
@article {pmid24463735, year = {2014}, author = {Li, ZY and Wang, YZ and He, LM and Zheng, HJ}, title = {Metabolic profiles of prokaryotic and eukaryotic communities in deep-sea sponge Neamphius huxleyi [corrected]. indicated by metagenomics.}, journal = {Scientific reports}, volume = {4}, number = {}, pages = {3895}, doi = {10.1038/srep03895}, pmid = {24463735}, issn = {2045-2322}, mesh = {Animals ; Carbon Monoxide/metabolism ; *Metagenomics ; Nitrogen/metabolism ; Phylogeny ; Porifera/chemistry/*genetics/metabolism ; Symbiosis ; }, abstract = {The whole metabolism of a sponge holobiont and the respective contributions of prokaryotic and eukaryotic symbionts and their associations with the sponge host remain largely unclear. Meanwhile, compared with shallow water sponges, deep-sea sponges are rarely understood. Here we report the metagenomic exploration of deep-sea sponge Neamphius huxleyi [corrected] . at the whole community level. Metagenomic data showed phylogenetically diverse prokaryotes and eukaryotes in Neamphius huxleyi [corrected]. MEGAN and gene enrichment analyses indicated different metabolic potentials of prokaryotic symbionts from eukaryotic symbionts, especially in nitrogen and carbon metabolisms, and their molecular interactions with the sponge host. These results supported the hypothesis that prokaryotic and eukaryotic symbionts have different ecological roles and relationships with sponge host. Moreover, vigorous denitrification, and CO2 fixation by chemoautotrophic prokaryotes were suggested for this deep-sea sponge. The study provided novel insights into the respective potentials of prokaryotic and eukaryotic symbionts and their associations with deep-sea sponge Neamphius huxleyi [corrected].}, }
@article {pmid24454815, year = {2014}, author = {Shinzato, C and Inoue, M and Kusakabe, M}, title = {A snapshot of a coral &quot;holobiont&quot;: a transcriptome assembly of the scleractinian coral, porites, captures a wide variety of genes from both the host and symbiotic zooxanthellae.}, journal = {PloS one}, volume = {9}, number = {1}, pages = {e85182}, doi = {10.1371/journal.pone.0085182}, pmid = {24454815}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*genetics ; Polymorphism, Genetic ; *Symbiosis ; *Transcriptome ; }, abstract = {Massive scleractinian corals of the genus Porites are important reef builders in the Indo-Pacific, and they are more resistant to thermal stress than other stony corals, such as the genus Acropora. Because coral health and survival largely depend on the interaction between a coral host and its symbionts, it is important to understand the molecular interactions of an entire &quot;coral holobiont&quot;. We simultaneously sequenced transcriptomes of Porites australiensis and its symbionts using the Illumina Hiseq2000 platform. We obtained 14.3 Gbp of sequencing data and assembled it into 74,997 contigs (average: 1,263 bp, N50 size: 2,037 bp). We successfully distinguished contigs originating from the host (Porites) and the symbiont (Symbiodinium) by aligning nucleotide sequences with the decoded Acropora digitifera and Symbiodinium minutum genomes. In contrast to previous coral transcriptome studies, at least 35% of the sequences were found to have originated from the symbionts, indicating that it is possible to analyze both host and symbiont transcriptomes simultaneously. Conserved protein domain and KEGG analyses showed that the dataset contains broad gene repertoires of both Porites and Symbiodinium. Effective utilization of sequence reads revealed that the polymorphism rate in P. australiensis is 1.0% and identified the major symbiotic Symbiodinium as Type C15. Analyses of amino acid biosynthetic pathways suggested that this Porites holobiont is probably able to synthesize most of the common amino acids and that Symbiodinium is potentially able to provide essential amino acids to its host. We believe this to be the first molecular evidence of complementarity in amino acid metabolism between coral hosts and their symbionts. We successfully assembled genes originating from both the host coral and the symbiotic Symbiodinium to create a snapshot of the coral holobiont transcriptome. This dataset will facilitate a deeper understanding of molecular mechanisms of coral symbioses and stress responses.}, }
@article {pmid24454551, year = {2014}, author = {Reusch, TB}, title = {Climate change in the oceans: evolutionary versus phenotypically plastic responses of marine animals and plants.}, journal = {Evolutionary applications}, volume = {7}, number = {1}, pages = {104-122}, doi = {10.1111/eva.12109}, pmid = {24454551}, issn = {1752-4571}, abstract = {I summarize marine studies on plastic versus adaptive responses to global change. Due to the lack of time series, this review focuses largely on the potential for adaptive evolution in marine animals and plants. The approaches were mainly synchronic comparisons of phenotypically divergent populations, substituting spatial contrasts in temperature or CO2 environments for temporal changes, or in assessments of adaptive genetic diversity within populations for traits important under global change. The available literature is biased towards gastropods, crustaceans, cnidarians and macroalgae. Focal traits were mostly environmental tolerances, which correspond to phenotypic buffering, a plasticity type that maintains a functional phenotype despite external disturbance. Almost all studies address coastal species that are already today exposed to fluctuations in temperature, pH and oxygen levels. Recommendations for future research include (i) initiation and analyses of observational and experimental temporal studies encompassing diverse phenotypic traits (including diapausing cues, dispersal traits, reproductive timing, morphology) (ii) quantification of nongenetic trans-generational effects along with components of additive genetic variance (iii) adaptive changes in microbe-host associations under the holobiont model in response to global change (iv) evolution of plasticity patterns under increasingly fluctuating environments and extreme conditions and (v) joint consideration of demography and evolutionary adaptation in evolutionary rescue approaches.}, }
@article {pmid24452239, year = {2014}, author = {Sela, DA and Mills, DA}, title = {The marriage of nutrigenomics with the microbiome: the case of infant-associated bifidobacteria and milk.}, journal = {The American journal of clinical nutrition}, volume = {99}, number = {3}, pages = {697S-703S}, doi = {10.3945/ajcn.113.071795}, pmid = {24452239}, issn = {1938-3207}, support = {R01 AT007079/AT/NCCIH NIH HHS/United States ; }, mesh = {Animals ; Bifidobacterium/*growth &amp; development/metabolism ; Biomedical Research/trends ; *Child Development ; *Evidence-Based Medicine ; Humans ; Infant ; Infant Formula ; *Infant Nutritional Physiological Phenomena ; Infant, Newborn ; Intestines/growth &amp; development/*microbiology ; Milk ; *Milk, Human ; Nutrigenomics/methods/trends ; *Symbiosis ; }, abstract = {Broadly, nutrigenomics examines the association of exogenous nutrients and molecular responses to maintain homeostasis in an individual. Phenotypic expression profiling, often transcriptomics, has been applied to identify markers and metabolic consequences of suboptimal diet, lifestyle, or both. The decade after the Human Genome Project has been marked with advances in high-throughput analysis of biological polymers and metabolites, prompting a rapid increase in characterization of the profound nature by which our symbiotic microbiota influences human physiology. Although the technology is widely accessible to assess microbiome composition, genetic potential, and global function, nutrigenomics studies often exclude the microbial contribution to host responses to ingested nutritive molecules. Perhaps a hallmark of coevolution, milk provides a dramatic example of a diet that promotes a particular microbial community structure, because the lower infant gastrointestinal tract is often dominated by bifidobacteria that flourish on milk glycans. Systems-level approaches should continue to be applied to examine the microbial communities in the context of their host's dietary habits and metabolic status. In addition, studies of isolated microbiota species should be encouraged to inform clinical studies and interventions as well as community studies. Whereas nutrigenomics research is beginning to account for resident microbiota, the need remains to consistently consider our microscopic partners in the human holobiont.}, }
@article {pmid24447216, year = {2014}, author = {Dittami, SM and Eveillard, D and Tonon, T}, title = {A metabolic approach to study algal-bacterial interactions in changing environments.}, journal = {Molecular ecology}, volume = {23}, number = {7}, pages = {1656-1660}, doi = {10.1111/mec.12670}, pmid = {24447216}, issn = {1365-294X}, mesh = {Acclimatization ; Bacteria/*metabolism ; Biological Evolution ; Chlorophyta/*metabolism/*microbiology ; *Environment ; Models, Biological ; }, abstract = {Increasing evidence exists that bacterial communities interact with and shape the biology of algae and that their evolutionary histories are connected. Despite these findings, physiological studies were and still are generally carried out with axenic or at least antibiotic-treated cultures. Here, we argue that considering interactions between algae and associated bacteria is key to understanding their biology and evolution. To deal with the complexity of the resulting 'holobiont' system, a metabolism-centred approach that uses combined metabolic models for algae and associated bacteria is proposed. We believe that these models will be valuable tools both to study algal-bacterial interactions and to elucidate processes important for the acclimation of the holobiont to environmental changes.}, }
@article {pmid24373029, year = {2014}, author = {Lema, KA and Willis, BL and Bourne, DG}, title = {Amplicon pyrosequencing reveals spatial and temporal consistency in diazotroph assemblages of the Acropora millepora microbiome.}, journal = {Environmental microbiology}, volume = {16}, number = {10}, pages = {3345-3359}, doi = {10.1111/1462-2920.12366}, pmid = {24373029}, issn = {1462-2920}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/*classification/genetics/isolation &amp; purification ; *Microbiota/genetics ; *Nitrogen Fixation/genetics ; Oxidoreductases/genetics ; Proteobacteria/classification/genetics/isolation &amp; purification ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; }, abstract = {Diazotrophic bacteria potentially play an important functional role in supplying fixed nitrogen to the coral holobiont, but the value of such a partnership depends on the stability of the association. Here we evaluate the composition of diazotroph assemblages associated with the coral Acropora millepora throughout four seasons and at two reefs, an inshore and an offshore (mid-shelf) reef on the Great Barrier Reef, Australia. Amplicon pyrosequencing of the nifH gene revealed that diazotrophs are ubiquitous members of the bacterial community associated with A. millepora. Rhizobia (65% of the overall nifH sequences retrieved) and particularly Bradyrhizobia sp.-affiliated sequences (> 50% of rhizobia sequences) dominated diazotrophic assemblages across all coral samples from the two sites throughout the year. In contrast to this consistency in the spatial and temporal patterns of occurrence of diazotroph assemblages, the overall coral-associated bacterial community, assessed through amplicon sequencing of the general bacterial 16S ribosomal RNA gene, differed between inshore and mid-shelf reef locations. Sequences associated with the Oceanospirillales family, particularly with Endozoicomonas sp., dominated bacterial communities associated with inshore corals. Although rhizobia represented a variable and generally small fraction of the overall bacterial community associated with A. millepora, consistency in the structure of these diazotrophic assemblages suggests that they have a functional role in the coral holobiont.}, }
@article {pmid24372150, year = {2014}, author = {Foster, C and Portman, N and Chen, M and Šlapeta, J}, title = {Increased growth and pigment content of Chromera velia in mixotrophic culture.}, journal = {FEMS microbiology ecology}, volume = {88}, number = {1}, pages = {121-128}, doi = {10.1111/1574-6941.12275}, pmid = {24372150}, issn = {1574-6941}, mesh = {Alveolata/*growth &amp; development/isolation &amp; purification/physiology ; Animals ; Anthozoa/physiology ; Chlorophyll/metabolism ; *Coral Reefs ; Culture Media/chemistry ; Photosynthesis ; }, abstract = {The alveolate microalga Chromera velia is an evolutionarily significant organism, representing the closest photosynthetic relative of the parasitic Apicomplexa. Chromera velia has been detected in and isolated from several stony corals and can be readily cultured in vitro under strictly autotrophic conditions. However, little is known about the ecology of this organism in the coral holobiont, an environment in which it could potentially access abundant organic carbon sources. To understand the response of C. velia to ecologically relevant organic compounds in vitro, we tested a mixotrophic culture strategy by supplementing inorganic f-medium with sugars, sugar-alcohols, organic acids and amino acids. For 15 of the 18 tested growth media, culture growth rate was significantly higher than that of strictly autotrophic cultures, and in three of these, a significant increase in maximum culture density was observed. In cultures supplemented with glutamate or glycine, the chlorophyll content per cell was up to 11-fold higher than cultures grown in standard inorganic media. Together, the in vitro culture growth and pigment responses demonstrate an ability to respond to nutritional resources when available. We propose that C. velia is a facultative opportunist in environments similarly enriched in such organic compounds, such as the coral holobiont.}, }
@article {pmid24334358, year = {2013}, author = {Pratte, ZA}, title = {Microbial functional genes associated with coral health and disease.}, journal = {Diseases of aquatic organisms}, volume = {107}, number = {2}, pages = {161-171}, doi = {10.3354/dao02664}, pmid = {24334358}, issn = {0177-5103}, mesh = {Animals ; Anthozoa/*genetics ; Ecosystem ; Gene Expression Regulation/*physiology ; Genetic Variation ; Nitrogen/metabolism ; }, abstract = {Both the incidence and prevalence of coral disease are rapidly increasing, and as a consequence, many studies involving coral microbial associates have been conducted. However, very few of these have considered microbial functional genes. This is an underutilized approach for studying coral disease etiology which is capable of revealing the molecular processes of the coral microbial community. This review presents a summary of the known microbial functional genes that have been linked to coral health and disease. Overall functional gene diversity tended to be lower in healthy corals than diseased or bleached corals, and respiration and photosynthesis functional genes appeared to be crucial to coral health. Genes associated with the nitrogen cycle were the most studied, were highly represented within the coral holobiont, and their expression often shifted in diseased or stressed individuals. Carbon metabolism, such as fatty acid and amino acid catabolism, also tended to shift in unhealthy corals. Genes associated with sulfite respiration as well as dimethylsulfoniopropionate degradation have been detected, although they have yet to be directly associated with coral disease. In addition, genes associated with xenobiotic degradation, antibiotic resistance, virulence, and oxidative stress may all be involved in maintaining coral health. However, the links between these functional genes and their roles in interacting with the coral host are not clear. Continuing identification of coral-associated microbial functional genes within the coral holobiont should facilitate advances in the field of coral health and disease.}, }
@article {pmid24286558, year = {2014}, author = {Desriac, F and Le Chevalier, P and Brillet, B and Leguerinel, I and Thuillier, B and Paillard, C and Fleury, Y}, title = {Exploring the hologenome concept in marine bivalvia: haemolymph microbiota as a pertinent source of probiotics for aquaculture.}, journal = {FEMS microbiology letters}, volume = {350}, number = {1}, pages = {107-116}, doi = {10.1111/1574-6968.12308}, pmid = {24286558}, issn = {1574-6968}, mesh = {Animals ; Anti-Bacterial Agents/isolation &amp; purification/*pharmacology ; Aquaculture ; Bivalvia/*microbiology ; Cell Survival ; DNA, Bacterial/chemistry/genetics ; DNA, Ribosomal/chemistry/genetics ; Dose-Response Relationship, Drug ; France ; Gram-Negative Bacteria/drug effects ; Gram-Positive Bacteria/drug effects ; Hemocytes/drug effects ; Hemolymph/*microbiology ; Microbial Sensitivity Tests ; Microbiota ; Phylogeny ; Probiotics/*isolation &amp; purification ; Pseudoalteromonas/*chemistry/genetics/isolation &amp; purification ; RNA, Ribosomal, 16S/genetics ; }, abstract = {Haemolymph-associated microbiota of marine bivalves was explored for antibacterial activity against important aquaculture pathogens. A collection of 843 strains were cultured from the haemolymph of four bivalve species (Crassostrea gigas, Mytilus edulis, Pecten maximus and Tapes rhomboides) collected by deep-sea diving in the Glenan Archipelago (France). Cell-free culture supernatants were investigated for antibacterial activity using the well-diffusion assay. About 3% of haemolymph-associated cultivable bacteria displayed antibacterial activity toward Gram-negative pathogens. Among the active bacteria, Pseudoalteromonas strains exhibited the highest antibacterial activity. The cell-free culture supernatant of one of them, named hCg-51, was able to inhibit the growth of bacterial pathogens even after drastic dilution (1 : 1024). Hemocyte survival was not significantly altered in the presence of the haemolymph-associated strains assayed. Moreover, a dose-dependent beneficial effect on hemocyte survival rates was observed with the hCg-51 strain. These results suggest that haemolymph microbiota may participate in bivalve protection and therefore confer a health benefit on the host. As a result, the results highlight bivalve haemolymph microbiota as a promising novel source for aquaculture probiotics. This work also gives a first insight into the contribution of the haemolymph-associated microbiota as part of the bivalve 'hologenome'.}, }
@article {pmid24286462, year = {2014}, author = {Stilling, RM and Dinan, TG and Cryan, JF}, title = {Microbial genes, brain &amp; behaviour - epigenetic regulation of the gut-brain axis.}, journal = {Genes, brain, and behavior}, volume = {13}, number = {1}, pages = {69-86}, doi = {10.1111/gbb.12109}, pmid = {24286462}, issn = {1601-183X}, mesh = {Animals ; Brain/*metabolism/physiopathology ; *Chromatin Assembly and Disassembly ; *Epigenesis, Genetic ; Gene-Environment Interaction ; *Genes, Bacterial ; Host-Pathogen Interactions ; Humans ; Intestines/*microbiology ; *Microbiota ; Stress, Psychological/genetics/*microbiology ; }, abstract = {To date, there is rapidly increasing evidence for host-microbe interaction at virtually all levels of complexity, ranging from direct cell-to-cell communication to extensive systemic signalling, and involving various organs and organ systems, including the central nervous system. As such, the discovery that differential microbial composition is associated with alterations in behaviour and cognition has significantly contributed to establishing the microbiota-gut-brain axis as an extension of the well-accepted gut-brain axis concept. Many efforts have been focused on delineating a role for this axis in health and disease, ranging from stress-related disorders such as depression, anxiety and irritable bowel syndrome to neurodevelopmental disorders such as autism. There is also a growing appreciation of the role of epigenetic mechanisms in shaping brain and behaviour. However, the role of epigenetics in informing host-microbe interactions has received little attention to date. This is despite the fact that there are many plausible routes of interaction between epigenetic mechanisms and the host-microbiota dialogue. From this new perspective we put forward novel, yet testable, hypotheses. Firstly, we suggest that gut-microbial products can affect chromatin plasticity within their host's brain that in turn leads to changes in neuronal transcription and eventually alters host behaviour. Secondly, we argue that the microbiota is an important mediator of gene-environment interactions. Finally, we reason that the microbiota itself may be viewed as an epigenetic entity. In conclusion, the fields of (neuro)epigenetics and microbiology are converging at many levels and more interdisciplinary studies are necessary to unravel the full range of this interaction.}, }
@article {pmid24278392, year = {2013}, author = {Hughes, AD and Grottoli, AG}, title = {Heterotrophic compensation: a possible mechanism for resilience of coral reefs to global warming or a sign of prolonged stress?.}, journal = {PloS one}, volume = {8}, number = {11}, pages = {e81172}, doi = {10.1371/journal.pone.0081172}, pmid = {24278392}, issn = {1932-6203}, mesh = {Autotrophic Processes ; Carbon/metabolism ; *Coral Reefs ; Ecosystem ; *Global Warming ; *Heterotrophic Processes ; Phototrophic Processes ; Seasons ; Temperature ; }, abstract = {Thermally induced bleaching has caused a global decline in corals and the frequency of such bleaching events will increase. Thermal bleaching severely disrupts the trophic behaviour of the coral holobiont, reducing the photosynthetically derived energy available to the coral host. In the short term this reduction in energy transfer from endosymbiotic algae results in an energy deficit for the coral host. If the bleaching event is short-lived then the coral may survive this energy deficit by depleting its lipid reserves, or by increasing heterotrophic energy acquisition. We show for the first time that the coral animal is capable of increasing the amount of heterotrophic carbon incorporated into its tissues for almost a year following bleaching. This prolonged heterotrophic compensation could be a sign of resilience or prolonged stress. If the heterotrophic compensation is in fact an acclimatization response, then this physiological response could act as a buffer from future bleaching by providing sufficient heterotrophic energy to compensate for photoautotrophic energy losses during bleaching, and potentially minimizing the effect of subsequent elevated temperature stresses. However, if the elevated incorporation of zooplankton is a sign that the effects of bleaching continue to be stressful on the holobiont, even after 11 months of recovery, then this physiological response would indicate that complete coral recovery requires more than 11 months to achieve. If coral bleaching becomes an annual global phenomenon by mid-century, then present temporal refugia will not be sufficient to allow coral colonies to recover between bleaching events and coral reefs will become increasingly less resilient to future climate change. If, however, increasing their sequestration of zooplankton-derived nutrition into their tissues over prolonged periods of time is a compensating mechanism, the impacts of annual bleaching may be reduced. Thus, some coral species may be better equipped to face repeated bleaching stress than previously thought.}, }
@article {pmid24098768, year = {2013}, author = {Slapeta, J and Linares, MC}, title = {Combined amplicon pyrosequencing assays reveal presence of the apicomplexan &quot;type-N&quot; (cf. Gemmocystis cylindrus) and Chromera velia on the Great Barrier Reef, Australia.}, journal = {PloS one}, volume = {8}, number = {9}, pages = {e76095}, doi = {10.1371/journal.pone.0076095}, pmid = {24098768}, issn = {1932-6203}, mesh = {Alveolata/*genetics ; Animals ; Anthozoa/genetics/*parasitology ; Apicomplexa/*genetics/physiology ; Australia ; Base Sequence ; *Coral Reefs ; Likelihood Functions ; Models, Genetic ; Molecular Sequence Data ; Pacific Ocean ; *Phylogeny ; RNA, Ribosomal/genetics ; Sequence Alignment ; Sequence Analysis, RNA ; }, abstract = {BACKGROUND: The coral is predominantly composed of the metabolically dependent coral host and the photosynthetic dinoflagellate Symbiodinium sp. The system as a whole interacts with symbiotic eukaryotes, bacteria and viruses. Gemmocystiscylindrus (cf. &quot;type-N&quot; symbiont) belonging to the obligatory parasitic phylum Apicomplexa (Alveolata) is ubiquitous in the Caribbean coral, but its presence in the Great Barrier Reef coral has yet to be documented. Approaches allowing identification of the healthy community from the pathogenic or saprobic organisms are needed for sustainable coral reef monitoring.<br><br>We investigated the diversity of eukaryotes associated with a common reef-building corals from the southern Great Barrier Reef. We used three tag encoded 454 amplicon pyrosequencing assays targeting eukaryote small-subunit rRNA gene to demonstrate the presence of the apicomplexan type-N and a photosynthetic sister species to Apicomplexa-Chromeravelia. Amplicon pyrosequencing revealed presence of the small-subunit rRNA genes of known eukaryotic pathogens (Cryptosporidium and Cryptococcus). We therefore conducted bacterial tag encoded amplicon pyrosequencing assay for small-subunit rRNA gene to support effluent exposure of the coral. Bacteria of faecal origin (Enterobacteriales) formed 41% of total sequences in contrast to 0-2% of the coral-associated bacterial communities with and without C. velia, respectively.<br><br>SIGNIFICANCE: This is the first time apicomplexan type-N has been detected in the Great Barrier Reef. Eukaryote tag encoded amplicon pyrosequencing assays demonstrate presence of apicomplexan type-N and C. Velia in total coral DNA. The data highlight the need for combined approaches for eukaryotic diversity studies coupled with bacterial community assessment to achieve a more realistic goals of defining the holobiont community and assessing coral disease. With increasing evidence of Apicomplexa in coral reef environments, it is important not only to understand the evolution of these organisms but also identify their potential as pathogens.}, }
@article {pmid24039199, year = {2013}, author = {Tholey, A and Treitz, C and Kussmann, M and Bendixen, E and Schrimpf, SP and Hengartner, MO}, title = {Model organisms proteomics--from holobionts to human nutrition.}, journal = {Proteomics}, volume = {13}, number = {17}, pages = {2537-2541}, doi = {10.1002/pmic.201370144}, pmid = {24039199}, issn = {1615-9861}, mesh = {Animals ; Bacteria/genetics/immunology ; Humans ; Insecta/genetics/immunology ; Microbiota/genetics ; *Models, Animal ; *Models, Biological ; Nutritional Physiological Phenomena ; Plants/genetics ; Proteome/analysis/genetics/metabolism ; Proteomics/*methods ; }, abstract = {Model organisms are an important tool for the development and validation of analytical approaches for proteomics and for the study of basic mechanisms of biological processes. The Initiative on Model Organism Proteomics (iMOP) organized a session during the 11th HUPO World Congress in Boston in 2012, highlighting the potential of proteomics studies in model organism for the elucidation of important mechanisms regulating the interaction of humans with its environment. Major subjects were the use of model organisms for the study of molecular events triggering the interaction of host organisms with the surrounding microbiota and the elucidation of the complex influence of nutrition on the health of human beings.}, }
@article {pmid24035647, year = {2013}, author = {Brucker, RM and Bordenstein, SR}, title = {The capacious hologenome.}, journal = {Zoology (Jena, Germany)}, volume = {116}, number = {5}, pages = {260-261}, doi = {10.1016/j.zool.2013.08.003}, pmid = {24035647}, issn = {1873-2720}, mesh = {Animals ; *Genome ; *Microbiota ; *Symbiosis ; }, abstract = {Blending disciplines can be transformative in science, yet interdisciplinary mergers should not escape healthy skepticism. Indeed, the history of biology shows us that debates about the relative importance of nuclear genetics vs. microbial symbiosis in eukaryotic biology are among the most engaging. Today's technology may help resolve this century old debate as it illuminates the interwoven genomics and functions of symbionts with their host genome. Thus, we can now assert that all subdisciplines of zoology require microbiology. Although controversial to some, the evidence from studies of host-associated microbial communities indicates that metazoans are hologenomes - interconnected compositions of animal and microbes.}, }
@article {pmid24023627, year = {2013}, author = {Denis, V and Guillaume, MM and Goutx, M and de Palmas, S and Debreuil, J and Baker, AC and Boonstra, RK and Bruggemann, JH}, title = {Fast growth may impair regeneration capacity in the branching coral Acropora muricata.}, journal = {PloS one}, volume = {8}, number = {8}, pages = {e72618}, doi = {10.1371/journal.pone.0072618}, pmid = {24023627}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*growth &amp; development/*physiology ; Calcification, Physiologic ; *Coral Reefs ; Regeneration/*physiology ; Reunion ; }, abstract = {Regeneration of artificially induced lesions was monitored in nubbins of the branching coral Acropora muricata at two reef-flat sites representing contrasting environments at Réunion Island (21°07'S, 55°32'E). Growth of these injured nubbins was examined in parallel, and compared to controls. Biochemical compositions of the holobiont and the zooxanthellae density were determined at the onset of the experiment, and the photosynthetic efficiency (Fv/Fm) of zooxanthellae was monitored during the experiment. Acropora muricata rapidly regenerated small lesions, but regeneration rates significantly differed between sites. At the sheltered site characterized by high temperatures, temperature variations, and irradiance levels, regeneration took 192 days on average. At the exposed site, characterized by steadier temperatures and lower irradiation, nubbins demonstrated fast lesion repair (81 days), slower growth, lower zooxanthellae density, chlorophyll a concentration and lipid content than at the former site. A trade-off between growth and regeneration rates was evident here. High growth rates seem to impair regeneration capacity. We show that environmental conditions conducive to high zooxanthellae densities in corals are related to fast skeletal growth but also to reduced lesion regeneration rates. We hypothesize that a lowered regenerative capacity may be related to limited availability of energetic and cellular resources, consequences of coral holobionts operating at high levels of photosynthesis and associated growth.}, }
@article {pmid24003149, year = {2013}, author = {Franzenburg, S and Walter, J and Künzel, S and Wang, J and Baines, JF and Bosch, TC and Fraune, S}, title = {Distinct antimicrobial peptide expression determines host species-specific bacterial associations.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {110}, number = {39}, pages = {E3730-8}, doi = {10.1073/pnas.1304960110}, pmid = {24003149}, issn = {1091-6490}, mesh = {Animals ; Antimicrobial Cationic Peptides/*metabolism ; Bacteria/growth &amp; development/*immunology ; Coculture Techniques ; Colony Count, Microbial ; Gene Knockdown Techniques ; Gene Silencing ; *Host Specificity ; Hydra/growth &amp; development/*metabolism/*microbiology ; Microbiota ; Molecular Sequence Data ; Phylogeny ; }, abstract = {Animals are colonized by coevolved bacterial communities, which contribute to the host's health. This commensal microbiota is often highly specific to its host-species, inferring strong selective pressures on the associated microbes. Several factors, including diet, mucus composition, and the immune system have been proposed as putative determinants of host-associated bacterial communities. Here we report that species-specific antimicrobial peptides account for different bacterial communities associated with closely related species of the cnidarian Hydra. Gene family extensions for potent antimicrobial peptides, the arminins, were detected in four Hydra species, with each species possessing a unique composition and expression profile of arminins. For functional analysis, we inoculated arminin-deficient and control polyps with bacterial consortia characteristic for different Hydra species and compared their selective preferences by 454 pyrosequencing of the bacterial microbiota. In contrast to control polyps, arminin-deficient polyps displayed decreased potential to select for bacterial communities resembling their native microbiota. This finding indicates that species-specific antimicrobial peptides shape species-specific bacterial associations.}, }
@article {pmid23997654, year = {2012}, author = {Shearer, T and Rasher, D and Snell, T and Hay, M}, title = {Gene expression patterns of the coral Acropora millepora in response to contact with macroalgae.}, journal = {Coral reefs (Online)}, volume = {31}, number = {4}, pages = {1177-1192}, doi = {10.1007/s00338-012-0943-7}, pmid = {23997654}, issn = {1432-0975}, support = {G12 RR003034/RR/NCRR NIH HHS/United States ; S21 MD000101/MD/NIMHD NIH HHS/United States ; U01 TW007401/TW/FIC NIH HHS/United States ; U19 TW007401/TW/FIC NIH HHS/United States ; }, abstract = {Contact with macroalgae often causes coral mortality, but the roles of abrasion versus shading versus allelopathy in these interactions are rarely clear and effects on gene expression are unknown. Identification of gene expression changes within corals in response to contact with macroalgae can provide insight into the mode of action of allelochemicals, as well as reveal transcriptional strategies of the coral that mitigate damage from this competitive interaction, enabling the coral to survive. Gene expression responses of the coral Acropora millepora after long-term (20 d) direct contact with macroalgae (Chlorodesmis fastigiata, Dictyota bartayresiana, Galaxaura filamentosa and Turbinaria conoides) and short-term (1 h and 24 h) exposure to C. fastigiata thalli and their hydrophobic extract were assessed. After 20 d of exposure, T. conoides thalli elicited no significant change in visual bleaching or zooxanthellae PSII quantum yield within A. millepora nubbins, but stimulated the greatest alteration in gene expression of all treatments. Chlorodesmis fastigiata, D. bartayresiana and G. filamentosa caused significant visual bleaching of coral nubbins and reduced the PSII quantum yield of associated zooxanthellae after 20 d, but elicited fewer changes in gene expression relative to T. conoides at day 20. To evaluate initial molecular processes leading to reduction of zooxanthella PSII quantum yield, visual bleaching, and coral death, short-term exposures to C. fastigiata thalli and hydrophobic extracts were conducted; these interactions revealed protein degradation and significant changes in catalytic and metabolic activity within 24 h of contact. These molecular responses are consistent with the hypothesis that allelopathic interactions lead to alteration of signal transduction and an imbalance between reactive oxidant species production and antioxidant capabilities within the coral holobiont. This oxidative imbalance results in rapid protein degradation and eventually to apoptosis and/or necrosis when compensatory transcriptional action by the coral holobiont insufficiently mitigates damage by the allelochemicals of C. fastigiata.}, }
@article {pmid23985749, year = {2014}, author = {Cavalcanti, GS and Gregoracci, GB and dos Santos, EO and Silveira, CB and Meirelles, PM and Longo, L and Gotoh, K and Nakamura, S and Iida, T and Sawabe, T and Rezende, CE and Francini-Filho, RB and Moura, RL and Amado-Filho, GM and Thompson, FL}, title = {Physiologic and metagenomic attributes of the rhodoliths forming the largest CaCO3 bed in the South Atlantic Ocean.}, journal = {The ISME journal}, volume = {8}, number = {1}, pages = {52-62}, doi = {10.1038/ismej.2013.133}, pmid = {23985749}, issn = {1751-7370}, mesh = {Animals ; Archaea/classification/genetics/metabolism/*physiology ; Atlantic Ocean ; Bacteria/classification/genetics/metabolism ; *Bacterial Physiological Phenomena ; *Biodiversity ; Brazil ; Calcium Carbonate/*metabolism ; Carbon/metabolism ; *Ecosystem ; Invertebrates/physiology ; Metagenome/*genetics ; Photosynthesis/genetics ; Rhodophyta/*microbiology ; }, abstract = {Rhodoliths are free-living coralline algae (Rhodophyta, Corallinales) that are ecologically important for the functioning of marine environments. They form extensive beds distributed worldwide, providing a habitat and nursery for benthic organisms and space for fisheries, and are an important source of calcium carbonate. The Abrolhos Bank, off eastern Brazil, harbors the world's largest continuous rhodolith bed (of ∼21,000 km(2)) and has one of the largest marine CaCO3 deposits (producing 25 megatons of CaCO3 per year). Nevertheless, there is a lack of information about the microbial diversity, photosynthetic potential and ecological interactions within the rhodolith holobiont. Herein, we performed an ecophysiologic and metagenomic analysis of the Abrolhos rhodoliths to understand their microbial composition and functional components. Rhodoliths contained a specific microbiome that displayed a significant enrichment in aerobic ammonia-oxidizing betaproteobacteria and dissimilative sulfate-reducing deltaproteobacteria. We also observed a significant contribution of bacterial guilds (that is, photolithoautotrophs, anaerobic heterotrophs, sulfide oxidizers, anoxygenic phototrophs and methanogens) in the rhodolith metagenome, suggested to have important roles in biomineralization. The increased hits in aromatic compounds, fatty acid and secondary metabolism subsystems hint at an important chemically mediated interaction in which a functional job partition among eukaryal, archaeal and bacterial groups allows the rhodolith holobiont to thrive in the global ocean. High rates of photosynthesis were measured for Abrolhos rhodoliths (52.16 μmol carbon m(-2)s(-1)), allowing the entire Abrolhos rhodolith bed to produce 5.65 × 10(5) tons C per day. This estimate illustrates the great importance of the Abrolhos rhodolith beds for dissolved carbon production in the South Atlantic Ocean.}, }
@article {pmid23963908, year = {2013}, author = {Gordon, BR and Leggat, W and Motti, CA}, title = {Extraction protocol for nontargeted NMR and LC-MS metabolomics-based analysis of hard coral and their algal symbionts.}, journal = {Methods in molecular biology (Clifton, N.J.)}, volume = {1055}, number = {}, pages = {129-147}, doi = {10.1007/978-1-62703-577-4_10}, pmid = {23963908}, issn = {1940-6029}, mesh = {Animals ; Anthozoa/*chemistry/*metabolism ; Chlorophyta/chemistry/metabolism/physiology ; Chromatography, Liquid/*methods ; Magnetic Resonance Spectroscopy/*methods ; Mass Spectrometry/*methods ; Metabolomics/*methods ; Symbiosis ; }, abstract = {Metabolomics and in particular, nontargeted metabolomics, has become a popular technique for the study of biological samples as it provides considerable amounts of information on extractable metabolites and is ideal for studying the metabolic response of an organism to stressors in its environment. One such organism, the symbiotic hard coral, presents its own complexity when considering a metabolomics approach in that it forms intricate associations with an array of symbiotic macro- and microbiota. While not discounting the importance of these many associations to the function of the coral holobiont, the coral-Symbiodinium relationship has been the most studied to date and as such, is the primary focus of this extraction protocol. This protocol provides details for the sample collection, extraction, and measurement of hard coral holobiont metabolites using both (1)H nuclear magnetic resonance (NMR) spectroscopy and liquid chromatography coupled with mass spectrometry (LC-MS). Using this nontargeted metabolomics approach, the holobiont metabolism can be investigated for perturbations resulting from either (1) natural or anthropogenic environmental challenges, (2) the controlled application of stressors, and (3) differences between phenotypes or species. Consequently, this protocol will benefit both environmental and natural products based research of hard coral and their algal symbionts. Every effort has been made to provide the reader with all the details required to perform this protocol, including many of the costly and time consuming &quot;pitfalls&quot; or &quot;traps&quot; that were discovered during its development. As a result, this protocol can be confidently accomplished by those with less experience in the extraction and analysis of symbiotic hard coral, requiring minimal user input whilst ensuring reproducible and reliable results using readily available lab ware and reagents.}, }
@article {pmid23940737, year = {2013}, author = {Li, J and Chen, Q and Zhang, S and Huang, H and Yang, J and Tian, XP and Long, LJ}, title = {Highly heterogeneous bacterial communities associated with the South China Sea reef corals Porites lutea, Galaxea fascicularis and Acropora millepora.}, journal = {PloS one}, volume = {8}, number = {8}, pages = {e71301}, doi = {10.1371/journal.pone.0071301}, pmid = {23940737}, issn = {1932-6203}, mesh = {Alphaproteobacteria/genetics ; Animals ; Anthozoa/*microbiology ; Betaproteobacteria/genetics ; China ; *Coral Reefs ; Flavobacteriaceae/genetics ; Gammaproteobacteria/genetics ; High-Throughput Nucleotide Sequencing ; Microbiota/*genetics ; Molecular Typing ; Oceans and Seas ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; Rhodobacteraceae/genetics ; Sequence Analysis, DNA ; }, abstract = {Coral harbor diverse and specific bacteria play significant roles in coral holobiont function. Bacteria associated with three of the common and phylogenetically divergent reef-building corals in the South China Sea, Porites lutea, Galaxea fascicularis and Acropora millepora, were investigated using 454 barcoded-pyrosequencing. Three colonies of each species were sampled, and 16S rRNA gene libraries were constructed individually. Analysis of pyrosequencing libraries showed that bacterial communities associated with the three coral species were more diverse than previous estimates based on corals from the Caribbean Sea, Indo-Pacific reefs and the Red Sea. Three candidate phyla, including BRC1, OD1 and SR1, were found for the first time in corals. Bacterial communities were separated into three groups: P. lutea and G. fascicular, A. millepora and seawater. P. lutea and G. fascicular displayed more similar bacterial communities, and bacterial communities associated with A. millepora differed from the other two coral species. The three coral species shared only 22 OTUs, which were distributed in Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, Chloroflexi, Actinobacteria, Acidobacteria and an unclassified bacterial group. The composition of bacterial communities within each colony of each coral species also showed variation. The relatively small common and large specific bacterial communities in these corals implies that bacterial associations may be structured by multiple factors at different scales and that corals may associate with microbes in terms of similar function, rather than identical species.}, }
@article {pmid23906315, year = {2013}, author = {Kenkel, CD and Goodbody-Gringley, G and Caillaud, D and Davies, SW and Bartels, E and Matz, MV}, title = {Evidence for a host role in thermotolerance divergence between populations of the mustard hill coral (Porites astreoides) from different reef environments.}, journal = {Molecular ecology}, volume = {22}, number = {16}, pages = {4335-4348}, doi = {10.1111/mec.12391}, pmid = {23906315}, issn = {1365-294X}, mesh = {Acclimatization/genetics/physiology ; Animals ; Anthozoa/genetics/*physiology ; Climate Change ; Coral Reefs ; Dinoflagellida/genetics/*physiology ; Florida ; *Hot Temperature ; *Population Dynamics ; *Symbiosis ; }, abstract = {Studying the mechanisms that enable coral populations to inhabit spatially varying thermal environments can help evaluate how they will respond in time to the effects of global climate change and elucidate the evolutionary forces that enable or constrain adaptation. Inshore reefs in the Florida Keys experience higher temperatures than offshore reefs for prolonged periods during the summer. We conducted a common garden experiment with heat stress as our selective agent to test for local thermal adaptation in corals from inshore and offshore reefs. We show that inshore corals are more tolerant of a 6-week temperature stress than offshore corals. Compared with inshore corals, offshore corals in the 31 °C treatment showed significantly elevated bleaching levels concomitant with a tendency towards reduced growth. In addition, dinoflagellate symbionts (Symbiodinium sp.) of offshore corals exhibited reduced photosynthetic efficiency. We did not detect differences in the frequencies of major (>5%) haplotypes comprising Symbiodinium communities hosted by inshore and offshore corals, nor did we observe frequency shifts ('shuffling') in response to thermal stress. Instead, coral host populations showed significant genetic divergence between inshore and offshore reefs, suggesting that in Porites astreoides, the coral host might play a prominent role in holobiont thermotolerance. Our results demonstrate that coral populations inhabiting reefs <10-km apart can exhibit substantial differences in their physiological response to thermal stress, which could impact their population dynamics under climate change.}, }
@article {pmid23899402, year = {2013}, author = {Kenkel, CD and Meyer, E and Matz, MV}, title = {Gene expression under chronic heat stress in populations of the mustard hill coral (Porites astreoides) from different thermal environments.}, journal = {Molecular ecology}, volume = {22}, number = {16}, pages = {4322-4334}, doi = {10.1111/mec.12390}, pmid = {23899402}, issn = {1365-294X}, mesh = {Animals ; Anthozoa/genetics/*metabolism/physiology ; Climate Change ; Ecosystem ; *Gene Expression Profiling ; Gene Expression Regulation ; Heat-Shock Response/*genetics/physiology ; *Hot Temperature ; Transcriptome ; }, abstract = {Recent evidence suggests that corals can acclimatize or adapt to local stress factors through differential regulation of their gene expression. Profiling gene expression in corals from diverse environments can elucidate the physiological processes that may be responsible for maximizing coral fitness in their natural habitat and lead to a better understanding of the coral's capacity to survive the effects of global climate change. In an accompanying paper, we show that Porites astreoides from thermally different reef habitats exhibit distinct physiological responses when exposed to 6 weeks of chronic temperature stress in a common garden experiment. Here, we describe expression profiles obtained from the same corals for a panel of 9 previously reported and 10 novel candidate stress response genes identified in a pilot RNA-Seq experiment. The strongest expression change was observed in a novel candidate gene potentially involved in calcification, SLC26, a member of the solute carrier family 26 anion exchangers, which was down-regulated by 92-fold in bleached corals relative to controls. The most notable signature of divergence between coral populations was constitutive up-regulation of metabolic genes in corals from the warmer inshore location, including the gluconeogenesis enzymes pyruvate carboxylase and phosphoenolpyruvate carboxykinase and the lipid beta-oxidation enzyme acyl-CoA dehydrogenase. Our observations highlight several molecular pathways that were not previously implicated in the coral stress response and suggest that host management of energy budgets might play an adaptive role in holobiont thermotolerance.}, }
@article {pmid23889801, year = {2013}, author = {Dunlap, WC and Starcevic, A and Baranasic, D and Diminic, J and Zucko, J and Gacesa, R and van Oppen, MJ and Hranueli, D and Cullum, J and Long, PF}, title = {KEGG orthology-based annotation of the predicted proteome of Acropora digitifera: ZoophyteBase - an open access and searchable database of a coral genome.}, journal = {BMC genomics}, volume = {14}, number = {}, pages = {509}, doi = {10.1186/1471-2164-14-509}, pmid = {23889801}, issn = {1471-2164}, support = {BB/H010009/2//Biotechnology and Biological Sciences Research Council/United Kingdom ; }, mesh = {*Access to Information ; Animals ; Anthozoa/*genetics ; Conservation of Natural Resources ; Coral Reefs ; *Data Mining ; *Databases, Genetic ; Internet ; Molecular Sequence Annotation/*methods ; Proteomics/*methods ; *Sequence Homology, Nucleic Acid ; }, abstract = {BACKGROUND: Contemporary coral reef research has firmly established that a genomic approach is urgently needed to better understand the effects of anthropogenic environmental stress and global climate change on coral holobiont interactions. Here we present KEGG orthology-based annotation of the complete genome sequence of the scleractinian coral Acropora digitifera and provide the first comprehensive view of the genome of a reef-building coral by applying advanced bioinformatics.<br><br>DESCRIPTION: Sequences from the KEGG database of protein function were used to construct hidden Markov models. These models were used to search the predicted proteome of A. digitifera to establish complete genomic annotation. The annotated dataset is published in ZoophyteBase, an open access format with different options for searching the data. A particularly useful feature is the ability to use a Google-like search engine that links query words to protein attributes. We present features of the annotation that underpin the molecular structure of key processes of coral physiology that include (1) regulatory proteins of symbiosis, (2) planula and early developmental proteins, (3) neural messengers, receptors and sensory proteins, (4) calcification and Ca2+-signalling proteins, (5) plant-derived proteins, (6) proteins of nitrogen metabolism, (7) DNA repair proteins, (8) stress response proteins, (9) antioxidant and redox-protective proteins, (10) proteins of cellular apoptosis, (11) microbial symbioses and pathogenicity proteins, (12) proteins of viral pathogenicity, (13) toxins and venom, (14) proteins of the chemical defensome and (15) coral epigenetics.<br><br>CONCLUSIONS: We advocate that providing annotation in an open-access searchable database available to the public domain will give an unprecedented foundation to interrogate the fundamental molecular structure and interactions of coral symbiosis and allow critical questions to be addressed at the genomic level based on combined aspects of evolutionary, developmental, metabolic, and environmental perspectives.}, }
@article {pmid23868918, year = {2013}, author = {Brucker, RM and Bordenstein, SR}, title = {The hologenomic basis of speciation: gut bacteria cause hybrid lethality in the genus Nasonia.}, journal = {Science (New York, N.Y.)}, volume = {341}, number = {6146}, pages = {667-669}, doi = {10.1126/science.1240659}, pmid = {23868918}, issn = {1095-9203}, mesh = {Animals ; Bacteria/*classification/genetics ; Chimera/microbiology/physiology ; Gastrointestinal Tract/*microbiology ; Germ-Free Life/genetics/*physiology ; Hymenoptera/genetics/*microbiology/*physiology ; Metagenome ; Phylogeny ; Species Specificity ; *Symbiosis ; }, abstract = {Although the gut microbiome influences numerous aspects of organismal fitness, its role in animal evolution and the origin of new species is largely unknown. Here we present evidence that beneficial bacterial communities in the guts of closely related species of the genus Nasonia form species-specific phylosymbiotic assemblages that cause lethality in interspecific hybrids. Bacterial constituents and abundance are irregular in hybrids relative to parental controls, and antibiotic curing of the gut bacteria significantly rescues hybrid survival. Moreover, feeding bacteria to germ-free hybrids reinstates lethality and recapitulates the expression of innate immune genes observed in conventionally reared hybrids. We conclude that in this animal complex, the gut microbiome and host genome represent a coadapted &quot;hologenome&quot; that breaks down during hybridization, promoting hybrid lethality and assisting speciation.}, }
@article {pmid23865748, year = {2013}, author = {Rodriguez-Lanetty, M and Granados-Cifuentes, C and Barberan, A and Bellantuono, AJ and Bastidas, C}, title = {Ecological Inferences from a deep screening of the Complex Bacterial Consortia associated with the coral, Porites astreoides.}, journal = {Molecular ecology}, volume = {22}, number = {16}, pages = {4349-4362}, doi = {10.1111/mec.12392}, pmid = {23865748}, issn = {1365-294X}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/classification/genetics/isolation &amp; purification ; Caribbean Region ; Coral Reefs ; Gammaproteobacteria/classification/genetics/*isolation &amp; purification ; High-Throughput Nucleotide Sequencing ; *Microbiota ; Molecular Sequence Data ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; *Symbiosis ; }, abstract = {The functional role of the bacterial organisms in the reef ecosystem and their contribution to the coral well-being remain largely unclear. The first step in addressing this gap of knowledge relies on in-depth characterization of the coral microbial community and its changes in diversity across coral species, space and time. In this study, we focused on the exploration of microbial community assemblages associated with an ecologically important Caribbean scleractinian coral, Porites astreoides, using Illumina high-throughput sequencing of the V5 fragment of 16S rRNA gene. We collected data from a large set of biological replicates, allowing us to detect patterns of geographical structure and resolve co-occurrence patterns using network analyses. The taxonomic analysis of the resolved diversity showed consistent and dominant presence of two OTUs affiliated with the order Oceanospirillales, which corroborates a specific pattern of bacterial association emerging for this coral species and for many other corals within the genus Porites. We argue that this specific association might indicate a symbiotic association with the adult coral partner. Furthermore, we identified a highly diverse rare bacterial 'biosphere' (725 OTUs) also living along with the dominant bacterial symbionts, but the assemblage of this biosphere is significantly structured along the geographical scale. We further discuss that some of these rare bacterial members show significant association with other members of the community reflecting the complexity of the networked consortia within the coral holobiont.}, }
@article {pmid23858648, year = {2013}, author = {Howells, EJ and Berkelmans, R and van Oppen, MJ and Willis, BL and Bay, LK}, title = {Historical thermal regimes define limits to coral acclimatization.}, journal = {Ecology}, volume = {94}, number = {5}, pages = {1078-1088}, pmid = {23858648}, issn = {0012-9658}, mesh = {*Acclimatization ; Animals ; Anthozoa/*physiology ; *Coral Reefs ; *Hot Temperature ; Time Factors ; }, abstract = {Knowledge of the degree to which corals undergo physiological acclimatization or genetic adaptation in response to changes in their thermal environment is crucial to the success of coral reef conservation strategies. The potential of corals to acclimatize to temperatures exceeding historical thermal regimes was investigated by reciprocal transplantation of Acropora millepora colonies between the warm central and cool southern regions of the Great Barrier Reef (GBR) for a duration of 14 months. Colony fragments retained at native sites remained healthy, whereas transplanted fragments, although healthy over initial months when temperatures remained within native thermal regimes, subsequently bleached and suffered mortality during seasonal temperature extremes. Corals hosting Symbiodinium D transplanted to the southern GBR bleached in winter and the majority suffered whole (40%; n=20 colonies) or partial (50%) mortality at temperatures 1.1 degrees C below their 15-year native minimum. In contrast, corals hosting Symbiodinium C2 transplanted to the central GBR bleached in summer and suffered whole (50%; n=10 colonies) or partial (42%) mortality at temperatures 2.5 degrees C above their 15-year native maximum. During summer bleaching, the dominant Symbiodinium type changed from C2 to D within corals transplanted to the central GBR. Corals transplanted to the cooler, southern GBR grew 74-80% slower than corals at their native site, and only 50% of surviving colonies reproduced, at least partially because of cold water bleaching of transplants. Despite the absence of any visual signs of stress, corals transplanted to the warmer, central GBR grew 52-59% more slowly than corals at their native site before the summer bleaching (i.e., from autumn to spring). Allocation of energy to initial acclimatization or reproduction may explain this pattern, as the majority (65%) of transplants reproduced one month earlier than portions of the same colonies retained at the southern native site. All parameters investigated (bleaching, mortality, Symbiodinium type fidelity, reproductive timing) demonstrated strong interactions between genotype and environment, indicating that the acclimatization potential of A. millepora populations may be limited by adaptation of the holobiont to native thermal regimes.}, }
@article {pmid23846183, year = {2013}, author = {Six, DL}, title = {The bark beetle holobiont: why microbes matter.}, journal = {Journal of chemical ecology}, volume = {39}, number = {7}, pages = {989-1002}, doi = {10.1007/s10886-013-0318-8}, pmid = {23846183}, issn = {1573-1561}, mesh = {Animals ; Climate Change ; Coleoptera/*microbiology ; *Microbiota ; *Symbiosis ; }, abstract = {All higher organisms are involved in symbioses with microbes. The importance of these partnerships has led to the concept of the holobiont, defined as the animal or plant with all its associated microbes. Indeed, the interactions between insects and symbionts form much of the basis for the success and diversity of this group of arthropods. Insects rely on microbes to perform basic life functions and to exploit resources and habitats. By &quot;partnering&quot; with microbes, insects access new genomic variation instantaneously allowing the exploitation of new adaptive zones, influencing not only outcomes in ecological time, but the degree of innovation and change that occurs over evolutionary time. In this review, I present a brief overview of the importance of insect-microbe holobionts to illustrate how critical an understanding of the holobiont is to understanding the insect host and it interactions with its environment. I then review what is known about the most influential insect holobionts in many forest ecosystems-bark beetles and their microbes-and how new approaches and technologies are allowing us to illuminate how these symbioses function. Finally, I discuss why it will be critical to study bark beetles as a holobiont to understand the ramifications and extent of anthropogenic change in forest ecosystems.}, }
@article {pmid23844217, year = {2013}, author = {Tonk, L and Sampayo, EM and Weeks, S and Magno-Canto, M and Hoegh-Guldberg, O}, title = {Host-specific interactions with environmental factors shape the distribution of symbiodinium across the Great Barrier Reef.}, journal = {PloS one}, volume = {8}, number = {7}, pages = {e68533}, doi = {10.1371/journal.pone.0068533}, pmid = {23844217}, issn = {1932-6203}, mesh = {Animals ; Biodiversity ; *Coral Reefs ; Dinoflagellida/*physiology ; Ecosystem ; *Environment ; Host Specificity ; Oceanography ; *Symbiosis ; }, abstract = {BACKGROUND: The endosymbiotic dinoflagellates (genus Symbiodinium) within coral reef invertebrates are critical to the survival of the holobiont. The genetic variability of Symbiodinium may contribute to the tolerance of the symbiotic association to elevated sea surface temperatures (SST). To assess the importance of factors such as the local environment, host identity and biogeography in driving Symbiodinium distributions on reef-wide scales, data from studies on reef invertebrate-Symbiodinium associations from the Great Barrier Reef (GBR) were compiled.<br><br>The resulting database consisted of 3717 entries from 26 studies. It was used to explore ecological patterns such as host-specificity and environmental drivers structuring community complexity using a multi-scalar approach. The data was analyzed in several ways: (i) frequently sampled host species were analyzed independently to investigate the influence of the environment on symbiont distributions, thereby excluding the influence of host specificity, (ii) host species distributions across sites were added as an environmental variable to determine the contribution of host identity on symbiont distribution, and (iii) data were pooled based on clade (broad genetic groups dividing the genus Symbiodinium) to investigate factors driving Symbiodinium distributions using lower taxonomic resolution. The results indicated that host species identity plays a dominant role in determining the distribution of Symbiodinium and environmental variables shape distributions on a host species-specific level. SST derived variables (especially SSTstdev) most often contributed to the selection of the best model. Clade level comparisons decreased the power of the predictive model indicating that it fails to incorporate the main drivers behind Symbiodinium distributions.<br><br>CONCLUSIONS/SIGNIFICANCE: Including the influence of different host species on Symbiodinium distributional patterns improves our understanding of the drivers behind the complexity of Symbiodinium-invertebrate symbioses. This will increase our ability to generate realistic models estimating the risk reefs are exposed to and their resilience in response to a changing climate.}, }
@article {pmid23840768, year = {2013}, author = {Vezzulli, L and Pezzati, E and Huete-Stauffer, C and Pruzzo, C and Cerrano, C}, title = {16SrDNA Pyrosequencing of the Mediterranean Gorgonian Paramuricea clavata Reveals a Link among Alterations in Bacterial Holobiont Members, Anthropogenic Influence and Disease Outbreaks.}, journal = {PloS one}, volume = {8}, number = {6}, pages = {e67745}, doi = {10.1371/journal.pone.0067745}, pmid = {23840768}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/classification/*genetics/isolation &amp; purification ; Bacterial Infections/*epidemiology/genetics/microbiology ; DNA, Bacterial/*genetics ; DNA, Ribosomal/*genetics ; *Disease Outbreaks ; Mediterranean Sea ; Sequence Analysis, DNA ; Symbiosis ; }, abstract = {Mass mortality events of benthic invertebrates in the Mediterranean Sea are becoming an increasing concern with catastrophic effects on the coastal marine environment. Sea surface temperature anomalies leading to physiological stress, starvation and microbial infections were identified as major factors triggering animal mortality. However the highest occurrence of mortality episodes in particular geographic areas and occasionally in low temperature deep environments suggest that other factors play a role as well. We conducted a comparative analysis of bacterial communities associated with the purple gorgonian Paramuricea clavata, one of the most affected species, collected at different geographic locations and depth, showing contrasting levels of anthropogenic disturbance and health status. Using massive parallel 16SrDNA gene pyrosequencing we showed that the bacterial community associated with healthy P. clavata in pristine locations was dominated by a single genus Endozoicomonas within the order Oceanospirillales which represented ∼90% of the overall bacterial community. P. clavata samples collected in human impacted areas and during disease events had higher bacterial diversity and abundance of disease-related bacteria, such as vibrios, than samples collected in pristine locations whilst showed a reduced dominance of Endozoicomonas spp. In contrast, bacterial symbionts exhibited remarkable stability in P. clavata collected both at euphotic and mesophotic depths in pristine locations suggesting that fluctuations in environmental parameters such as temperature have limited effect in structuring the bacterial holobiont. Interestingly the coral pathogen Vibrio coralliilyticus was not found on diseased corals collected during a deep mortality episode suggesting that neither temperature anomalies nor recognized microbial pathogens are solely sufficient to explain for the events. Overall our data suggest that anthropogenic influence may play a significant role in determining the coral health status by affecting the composition of the associated microbial community. Environmental stressful events and microbial infections may thus be superimposed to compromise immunity and trigger mortality outbreaks.}, }
@article {pmid23836873, year = {2013}, author = {Snyder, AK and Rio, RV}, title = {Interwoven biology of the tsetse holobiont.}, journal = {Journal of bacteriology}, volume = {195}, number = {19}, pages = {4322-4330}, doi = {10.1128/JB.00487-13}, pmid = {23836873}, issn = {1098-5530}, mesh = {Animals ; Bacteria/*classification/genetics ; Biological Evolution ; Symbiosis ; Tsetse Flies/genetics/*microbiology ; }, abstract = {Microbial symbionts can be instrumental to the evolutionary success of their hosts. Here, we discuss medically significant tsetse flies (Diptera: Glossinidae), a group comprised of over 30 species, and their use as a valuable model system to study the evolution of the holobiont (i.e., the host and associated microbes). We first describe the tsetse microbiota, which, despite its simplicity, harbors a diverse range of associations. The maternally transmitted microbes consistently include two Gammaproteobacteria, the obligate mutualists Wigglesworthia spp. and the commensal Sodalis glossinidius, along with the parasitic Alphaproteobacteria Wolbachia. These associations differ in their establishment times, making them unique and distinct from previously characterized symbioses, where multiple microbial partners have associated with their host for a significant portion of its evolution. We then expand into discussing the functional roles and intracommunity dynamics within this holobiont, which enhances our understanding of tsetse biology to encompass the vital functions and interactions of the microbial community. Potential disturbances influencing the tsetse microbiome, including salivary gland hypertrophy virus and trypanosome infections, are highlighted. While previous studies have described evolutionary consequences of host association for symbionts, the initial steps facilitating their incorporation into a holobiont and integration of partner biology have only begun to be explored. Research on the tsetse holobiont will contribute to the understanding of how microbial metabolic integration and interdependency initially may develop within hosts, elucidating mechanisms driving adaptations leading to cooperation and coresidence within the microbial community. Lastly, increased knowledge of the tsetse holobiont may also contribute to generating novel African trypanosomiasis disease control strategies.}, }
@article {pmid23750924, year = {2013}, author = {Kimes, NE and Johnson, WR and Torralba, M and Nelson, KE and Weil, E and Morris, PJ}, title = {The Montastraea faveolata microbiome: ecological and temporal influences on a Caribbean reef-building coral in decline.}, journal = {Environmental microbiology}, volume = {15}, number = {7}, pages = {2082-2094}, doi = {10.1111/1462-2920.12130}, pmid = {23750924}, issn = {1462-2920}, mesh = {Animals ; Anthozoa/*microbiology ; Archaea/genetics ; Bacteria/genetics ; Biodiversity ; Caribbean Region ; *Coral Reefs ; *Ecosystem ; Eukaryota/genetics ; Genes, rRNA/genetics ; Microbiota/*physiology ; Molecular Sequence Data ; Seasons ; }, abstract = {Coral-associated microbial communities, including protists, bacteria, archaea and viruses, are important components of the coral holobiont that influence the health of corals and coral reef ecosystems. Evidence suggests that the composition of these microbial communities is affected by numerous parameters; however, little is known about the confluence of these ecological and temporal effects. In this study, we used ribosomal RNA gene sequencing to identify the zooxanthellae, bacteria and archaea associated with healthy and yellow band diseased (YBD) colonies in the Media Luna reef of La Parguera, Puerto Rico, in order to examine the influence of YBD on the Montastraea faveolata microbiome. In addition, we evaluated the influence of season on the differences between healthy and YBD M. faveolata microbiomes by sampling from the same tagged colonies in both March and September of 2007. To the best of our knowledge, this is the first coral microbiome study to examine sequences from the zooxanthellar, bacterial and archaeal communities simultaneously from individual coral samples. Our results confirm differences in the M. faveolata zooxanthellar, bacterial and archaeal communities between healthy and YBD colonies in March; however, the September communities do not exhibit the same differences. Moreover, we provide evidence that the differences in the M. faveolata microbiomes between March and September are more significant than those observed between healthy and YBD. This data suggest that the entire coral microbiome, not just the bacterial community, is a dynamic environment where both disease and season play important roles.}, }
@article {pmid23694677, year = {2013}, author = {Singh, Y and Ahmad, J and Musarrat, J and Ehtesham, NZ and Hasnain, SE}, title = {Emerging importance of holobionts in evolution and in probiotics.}, journal = {Gut pathogens}, volume = {5}, number = {1}, pages = {12}, doi = {10.1186/1757-4749-5-12}, pmid = {23694677}, issn = {1757-4749}, abstract = {The existence of microbe free animals or plants in nature is virtually impossible as they and plants have a certain degree of symbiotic association with microbes. This symbiotic association leads to the formation of holobiont (host and its symbionts). This mutual coexistence is not merely at the physical or chemical level but also at the genetic level leading to the emergence of the concept of hologenome (gene pool of host and its associated symbionts). The abundance of symbionts with the associated gene diversity contributes to the fitness of the holobiont under varying environmental conditions. The hologenome theory of evolution considers the dynamic holobiont as a single unit for natural selection and provides a more accommodating view of evolution blending Darwinism and Lamarkism. Additionally, holobionts are providing scientific basis to our understanding of the growing importance of probiotics in human health and in disease management.}, }
@article {pmid23688194, year = {2013}, author = {Minard, G and Mavingui, P and Moro, CV}, title = {Diversity and function of bacterial microbiota in the mosquito holobiont.}, journal = {Parasites &amp; vectors}, volume = {6}, number = {}, pages = {146}, doi = {10.1186/1756-3305-6-146}, pmid = {23688194}, issn = {1756-3305}, mesh = {Animals ; Bacteria/*classification/*genetics ; Bacterial Physiological Phenomena ; *Biodiversity ; Culicidae/*microbiology ; Female ; Male ; *Metagenome ; Mosquito Control/methods ; Symbiosis ; }, abstract = {Mosquitoes (Diptera: Culicidae) have been shown to host diverse bacterial communities that vary depending on the sex of the mosquito, the developmental stage, and ecological factors. Some studies have suggested a potential role of microbiota in the nutritional, developmental and reproductive biology of mosquitoes. Here, we present a review of the diversity and functions of mosquito-associated bacteria across multiple variation factors, emphasizing recent findings. Mosquito microbiota is considered in the context of possible extended phenotypes conferred on the insect hosts that allow niche diversification and rapid adaptive evolution in other insects. These kinds of observations have prompted the recent development of new mosquito control methods based on the use of symbiotically-modified mosquitoes to interfere with pathogen transmission or reduce the host life span and reproduction. New opportunities for exploiting bacterial function for vector control are highlighted.}, }
@article {pmid23658817, year = {2013}, author = {Levas, SJ and Grottoli, AG and Hughes, A and Osburn, CL and Matsui, Y}, title = {Physiological and biogeochemical traits of bleaching and recovery in the mounding species of coral Porites lobata: implications for resilience in mounding corals.}, journal = {PloS one}, volume = {8}, number = {5}, pages = {e63267}, doi = {10.1371/journal.pone.0063267}, pmid = {23658817}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/metabolism/*physiology ; Conservation of Natural Resources ; *Geology ; *Pigmentation ; }, abstract = {Mounding corals survive bleaching events in greater numbers than branching corals. However, no study to date has determined the underlying physiological and biogeochemical trait(s) that are responsible for mounding coral holobiont resilience to bleaching. Furthermore, the potential of dissolved organic carbon (DOC) as a source of fixed carbon to bleached corals has never been determined. Here, Porites lobata corals were experimentally bleached for 23 days and then allowed to recover for 0, 1, 5, and 11 months. At each recovery interval a suite of analyses were performed to assess their recovery (photosynthesis, respiration, chlorophyll a, energy reserves, tissue biomass, calcification, δ(13)C of the skeletal, δ(13)C, and δ(15)N of the animal host and endosymbiont fractions). Furthermore, at 0 months of recovery, the assimilation of photosynthetically acquired and zooplankton-feeding acquired carbon into the animal host, endosymbiont, skeleton, and coral-mediated DOC were measured via (13)C-pulse-chase labeling. During the first month of recovery, energy reserves and tissue biomass in bleached corals were maintained despite reductions in chlorophyll a, photosynthesis, and the assimilation of photosynthetically fixed carbon. At the same time, P. lobata corals catabolized carbon acquired from zooplankton and seemed to take up DOC as a source of fixed carbon. All variables that were negatively affected by bleaching recovered within 5 to 11 months. Thus, bleaching resilience in the mounding coral P. lobata is driven by its ability to actively catabolize zooplankton-acquired carbon and seemingly utilize DOC as a significant fixed carbon source, facilitating the maintenance of energy reserves and tissue biomass. With the frequency and intensity of bleaching events expected to increase over the next century, coral diversity on future reefs may favor not only mounding morphologies but species like P. lobata, which have the ability to utilize heterotrophic sources of fixed carbon that minimize the impact of bleaching and promote fast recovery.}, }
@article {pmid23649754, year = {2013}, author = {Domaschke, S and Vivas, M and Sancho, LG and Printzen, C}, title = {Ecophysiology and genetic structure of polar versus temperate populations of the lichen Cetraria aculeata.}, journal = {Oecologia}, volume = {173}, number = {3}, pages = {699-709}, doi = {10.1007/s00442-013-2670-3}, pmid = {23649754}, issn = {1432-1939}, mesh = {Adaptation, Biological/genetics/*physiology ; Analysis of Variance ; Antarctic Regions ; Base Sequence ; Carbon Dioxide/metabolism ; Chlorophyll/analysis ; *Climate ; Germany ; Lichens/*genetics/*physiology ; Light ; Molecular Sequence Data ; Photosynthesis/physiology ; Sequence Analysis, DNA ; Spain ; Svalbard ; Temperature ; }, abstract = {We studied polar and temperate samples of the lichen Cetraria aculeata to investigate whether genetical differences between photobionts are correlated with physiological properties of the lichen holobiont. Net photosynthesis and dark respiration (DR) at different temperatures (from 0 to 30 °C) and photon flux densities (from 0 to 1,200 μmol m(-2) s(-1)) were studied for four populations of Cetraria aculeata. Samples were collected from maritime Antarctica, Svalbard, Germany and Spain, representing different climatic situations. Sequencing of the photobiont showed that the investigated samples fall in the polar and temperate clade described in Fernández-Mendoza et al. (Mol Ecol 20:1208-1232, 2011). Lichens with photobionts from these clades differ in their temperature optimum for photosynthesis, maximal net photosynthesis, maximal DR and chlorophyll content. Maximal net photosynthesis was much lower in Antarctica and Svalbard than in Germany and Spain. The difference was smaller when rates were expressed by chlorophyll content. The same is true for the temperature optima of polar (11 °C) and temperate (15 and 17 °C) lichens. Our results indicate that lichen mycobionts may adapt or acclimate to local environmental conditions either by selecting algae from regional pools or by regulating algal cell numbers (chlorophyll content) within the thallus.}, }
@article {pmid23645316, year = {2013}, author = {Walter, J and Martínez, I and Rose, DJ}, title = {Holobiont nutrition: considering the role of the gastrointestinal microbiota in the health benefits of whole grains.}, journal = {Gut microbes}, volume = {4}, number = {4}, pages = {340-346}, doi = {10.4161/gmic.24707}, pmid = {23645316}, issn = {1949-0984}, mesh = {*Diet ; *Edible Grain ; Female ; Gastrointestinal Tract/*microbiology ; Humans ; Male ; *Metagenome ; }, abstract = {Intake of whole grains and other food products high in dietary fiber have long been linked to the prevention of chronic diseases associated with inflammation. A contribution of the gastrointestinal microbiota to these effects has been suggested, but little is known on how whole grains interact with gut bacteria. We have recently published the first human trial that made use of next-generation sequencing to determine the effect of whole grains (whole grain barley, brown rice or a mixture of the two) on fecal microbiota structure and tested for associations between the gut microbiota and blood markers of inflammation, glucose and lipid metabolism. Our study revealed that whole grains impacted gut microbial ecology by increasing microbial diversity and inducing compositional alterations, some of which are considered to have beneficial effects on the host. Interestingly, whole grains, and in particular the combination of whole grain barley and brown rice, caused a reduction in plasma interleukin-6 (IL-6), which was linked to compositional features of the gut microbiota. Therefore, the study provided evidence that a short-term increased intake of whole grains led to compositional alterations of the gut microbiota that coincided with improvements in systemic inflammation. In this addendum, we summarize the findings of the study and provide a perspective on the importance of regarding humans as holobionts when considering the health effects of dietary strategies.}, }
@article {pmid23630625, year = {2013}, author = {Jessen, C and Villa Lizcano, JF and Bayer, T and Roder, C and Aranda, M and Wild, C and Voolstra, CR}, title = {In-situ effects of eutrophication and overfishing on physiology and bacterial diversity of the red sea coral Acropora hemprichii.}, journal = {PloS one}, volume = {8}, number = {4}, pages = {e62091}, doi = {10.1371/journal.pone.0062091}, pmid = {23630625}, issn = {1932-6203}, mesh = {Analysis of Variance ; Animals ; Anthozoa/microbiology/*physiology ; Bacteria/genetics ; Biodiversity ; Conservation of Natural Resources ; *Eutrophication ; *Fisheries ; Gammaproteobacteria/classification/*genetics ; High-Throughput Nucleotide Sequencing ; Indian Ocean ; Molecular Typing ; Nitrogen Fixation ; Phylogeny ; Principal Component Analysis ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, RNA ; }, abstract = {Coral reefs of the Central Red Sea display a high degree of endemism, and are increasingly threatened by anthropogenic effects due to intense local coastal development measures. Overfishing and eutrophication are among the most significant local pressures on these reefs, but there is no information available about their potential effects on the associated microbial community. Therefore, we compared holobiont physiology and 16S-based bacterial communities of tissue and mucus of the hard coral Acropora hemprichii after 1 and 16 weeks of in-situ inorganic nutrient enrichment (via fertilizer diffusion) and/or herbivore exclusion (via caging) in an offshore reef of the Central Red Sea. Simulated eutrophication and/or overfishing treatments did not affect coral physiology with respect to coral respiration rates, chlorophyll a content, zooxanthellae abundance, or δ (15)N isotopic signatures. The bacterial community of A. hemprichii was rich and uneven, and diversity increased over time in all treatments. While distinct bacterial species were identified as a consequence of eutrophication, overfishing, or both, two bacterial species that could be classified to the genus Endozoicomonas were consistently abundant and constituted two thirds of bacteria in the coral. Several nitrogen-fixing and denitrifying bacteria were found in the coral specimens that were exposed to experimentally increased nutrients. However, no particular bacterial species was consistently associated with the coral under a given treatment and the single effects of manipulated eutrophication and overfishing could not predict the combined effect. Our data underlines the importance of conducting field studies in a holobiont framework, taking both, physiological and molecular measures into account.}, }
@article {pmid23564007, year = {2013}, author = {Yang, S and Sun, W and Zhang, F and Li, Z}, title = {Phylogenetically diverse denitrifying and ammonia-oxidizing bacteria in corals Alcyonium gracillimum and Tubastraea coccinea.}, journal = {Marine biotechnology (New York, N.Y.)}, volume = {15}, number = {5}, pages = {540-551}, doi = {10.1007/s10126-013-9503-6}, pmid = {23564007}, issn = {1436-2236}, mesh = {Ammonia/metabolism ; Animals ; Anthozoa/*microbiology ; Bacteria/*genetics/*metabolism ; Base Sequence ; China ; Cluster Analysis ; Computational Biology ; DNA Primers/genetics ; Denitrification/genetics/physiology ; Gene Library ; Genetic Markers/genetics ; Microbiota/*genetics ; Molecular Sequence Data ; Nitrite Reductases/genetics ; Oceans and Seas ; Oxidation-Reduction ; Oxidoreductases/genetics ; *Phylogeny ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; Species Specificity ; *Symbiosis ; }, abstract = {To date, the association of coral-bacteria and the ecological roles of bacterial symbionts in corals remain largely unknown. In particular, little is known about the community components of bacterial symbionts of corals involved in the process of denitrification and ammonia oxidation. In this study, the nitrite reductase (nirS and nirK) and ammonia monooxygenase subunit A (amoA) genes were used as functional markers. Diverse bacteria with the potential to be active as denitrifiers and ammonia-oxidizing bacteria (AOB) were found in two East China Sea corals: stony coral Alcyonium gracillimum and soft coral Tubastraea coccinea. The 16S rRNA gene library analysis demonstrated different communities of bacterial symbionts in these two corals of the same location. Nitrite reductase nirK gene was found only in T. coccinea, while both nirK and nirS genes were detected in A. gracillimum, which might be the result of the presence of different bacterial symbionts in these two corals. AOB rather than ammonia-oxidizing archaea were detected in both corals, suggesting that AOB might play an important role in the ammonia oxidation process of the corals. This study indicates that the coral bacterial symbionts with the potential for nitrite reduction and ammonia oxidation might have multiple ecological roles in the coral holobiont, which promotes our understanding of bacteria-mediated nitrogen cycling in corals. To our knowledge, this study is the first assessment of the community structure and phylogenetic diversity of denitrifying bacteria and AOB in corals based on nirK, nirS, and amoA gene library analysis.}, }
@article {pmid23553821, year = {2013}, author = {Bell, JJ and Davy, SK and Jones, T and Taylor, MW and Webster, NS}, title = {Could some coral reefs become sponge reefs as our climate changes?.}, journal = {Global change biology}, volume = {19}, number = {9}, pages = {2613-2624}, doi = {10.1111/gcb.12212}, pmid = {23553821}, issn = {1354-1013}, mesh = {Animals ; *Climate Change ; *Coral Reefs ; *Porifera ; }, abstract = {Coral reefs across the world have been seriously degraded and have a bleak future in response to predicted global warming and ocean acidification (OA). However, this is not the first time that biocalcifying organisms, including corals, have faced the threat of extinction. The end-Triassic mass extinction (200 million years ago) was the most severe biotic crisis experienced by modern marine invertebrates, which selected against biocalcifiers; this was followed by the proliferation of another invertebrate group, sponges. The duration of this sponge-dominated period far surpasses that of alternative stable-ecosystem or phase-shift states reported on modern day coral reefs and, as such, a shift to sponge-dominated reefs warrants serious consideration as one future trajectory of coral reefs. We hypothesise that some coral reefs of today may become sponge reefs in the future, as sponges and corals respond differently to changing ocean chemistry and environmental conditions. To support this hypothesis, we discuss: (i) the presence of sponge reefs in the geological record; (ii) reported shifts from coral- to sponge-dominated systems; and (iii) direct and indirect responses of the sponge holobiont and its constituent parts (host and symbionts) to changes in temperature and pH. Based on this evidence, we propose that sponges may be one group to benefit from projected climate change and ocean acidification scenarios, and that increased sponge abundance represents a possible future trajectory for some coral reefs, which would have important implications for overall reef functioning.}, }
@article {pmid23545857, year = {2013}, author = {Wanick, RC and de Sousa Barbosa, H and Frazão, LR and Santelli, RE and Arruda, MA and Coutinho, CC}, title = {Evaluation of differential protein expression in Haliclona aquarius and sponge-associated microorganisms under cadmium stress.}, journal = {Analytical and bioanalytical chemistry}, volume = {405}, number = {24}, pages = {7661-7670}, doi = {10.1007/s00216-013-6898-x}, pmid = {23545857}, issn = {1618-2650}, mesh = {Animals ; Cadmium/*toxicity ; Electrophoresis, Gel, Two-Dimensional ; Gene Expression Regulation/*drug effects ; Haliclona/*genetics/metabolism/*microbiology ; Proteins/chemistry/*genetics ; Proteomics ; Spectrometry, Mass, Electrospray Ionization ; Water Pollutants, Chemical/*toxicity ; }, abstract = {A comparative proteomic approach was used to assess differentially expressed proteins in marine sponges after 36 h of exposure to cadmium (Cd). After separation performed by 2-D polyacrylamide gel electrophoresis, 46 protein spots indicated differential expression, and 17 of these proteins were identified by electrospray ionization quadrupole time-of-flight mass spectrometry. From the proteins identified, 76% were attributed to sponge-associated microorganisms (fungi and bacteria), and 24% were attributed to Haliclona aquarius. Some of the proteins that were identified may be related to cell proliferation and differentiation or processes of oxidative stress repair and energy procurement. An integrated evaluation based on spot expression levels and the postulated functions of these proteins allowed a more accurate evaluation of the stress caused to the sponge holobiont system by cadmium exposure. This study could provide new insights into the use of a proteomic approach in the marine sponge to assess the effects of Cd pollution in a marine environment.}, }
@article {pmid23531826, year = {2013}, author = {Béraud, E and Gevaert, F and Rottier, C and Ferrier-Pagès, C}, title = {The response of the scleractinian coral Turbinaria reniformis to thermal stress depends on the nitrogen status of the coral holobiont.}, journal = {The Journal of experimental biology}, volume = {216}, number = {Pt 14}, pages = {2665-2674}, doi = {10.1242/jeb.085183}, pmid = {23531826}, issn = {1477-9145}, mesh = {Ammonium Compounds/pharmacology ; Analysis of Variance ; Animals ; Anthozoa/metabolism/*physiology ; Calcification, Physiologic/drug effects ; Carotenoids ; Chlorophyll/metabolism ; Dinoflagellida/*drug effects/metabolism ; Fluorescence ; *Hot Temperature ; Indian Ocean ; Nitrogen/*metabolism/pharmacology ; Photosynthesis/drug effects/physiology ; Stress, Physiological/*physiology ; *Symbiosis ; Xanthophylls/metabolism ; beta Carotene/metabolism ; }, abstract = {The physiological response of the scleractinian coral Turbinaria reniformis to ammonium enrichment (3 μmol l(-1)) was examined at 26°C as well as during a 7 day increase in temperature to 31°C (thermal stress). At 26°C, ammonium supplementation had little effect on the coral physiology. It induced a decrease in symbiont density, compensated by an increase in chlorophyll content per symbiont cell. Organic carbon release was reduced, likely because of a better utilization of the photosynthesized carbon (i.e. incorporation into proteins, kept in the coral tissue). The δ(15)N signatures of the ammonium-enriched symbionts and host tissue were also significantly decreased, by 4 and 2‰, respectively, compared with the non-enriched conditions, suggesting a significant uptake of inorganic nitrogen by the holobiont. Under thermal stress, coral colonies that were not nitrogen enriched experienced a drastic decrease in photosynthetic and photoprotective pigments (chlorophyll a, β-carotene, diadinoxanthin, diatoxanthin and peridinin), followed by a decrease in the rates of photosynthesis and calcification. Organic carbon release was not affected by this thermal stress. Conversely, nitrogen-enriched corals showed an increase in their pigment concentrations, and maintained rates of photosynthesis and calcification at ca. 60% and 100% of those measured under control conditions, respectively. However, these corals lost more organic carbon into the environment. Overall, these results indicate that inorganic nitrogen availability can be important to determining the resilience of some scleractinian coral species to thermal stress, and can have a function equivalent to that of heterotrophic feeding concerning the maintenance of coral metabolism under stress conditions.}, }
@article {pmid23437379, year = {2013}, author = {La Rivière, M and Roumagnac, M and Garrabou, J and Bally, M}, title = {Transient shifts in bacterial communities associated with the temperate gorgonian Paramuricea clavata in the Northwestern Mediterranean Sea.}, journal = {PloS one}, volume = {8}, number = {2}, pages = {e57385}, doi = {10.1371/journal.pone.0057385}, pmid = {23437379}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*microbiology/physiology ; Bacteria/classification/*genetics/isolation &amp; purification ; Biodiversity ; *Coral Reefs ; Denaturing Gradient Gel Electrophoresis ; Ecosystem ; Gene Library ; Mediterranean Sea ; Microbial Consortia/*genetics ; Phylogeny ; Polymorphism, Restriction Fragment Length ; RNA, Ribosomal, 16S/classification/*genetics/isolation &amp; purification ; Ribotyping ; Sequence Analysis, DNA ; Symbiosis/physiology ; }, abstract = {BACKGROUND: Bacterial communities that are associated with tropical reef-forming corals are being increasingly recognized for their role in host physiology and health. However, little is known about the microbial diversity of the communities associated with temperate gorgonian corals, even though these communities are key structural components of the ecosystem. In the Northwestern Mediterranean Sea, gorgonians undergo recurrent mass mortalities, but the potential relationship between these events and the structure of the associated bacterial communities remains unexplored. Because microbial assemblages may contribute to the overall health and disease resistance of their host, a detailed baseline of the associated bacterial diversity is required to better understand the functioning of the gorgonian holobiont.<br><br>The bacterial diversity associated with the gorgonian Paramuricea clavata was determined using denaturing gradient gel electrophoresis, terminal-restriction fragment length polymorphism and the construction of clone libraries of the bacterial 16S ribosomal DNA. Three study sites were monitored for 4 years to assess the variability of communities associated with healthy colonies. Bacterial assemblages were highly dominated by one Hahellaceae-related ribotype and exhibited low diversity. While this pattern was mostly conserved through space and time, in summer 2007, a deep shift in microbiota structure toward increased bacterial diversity and the transient disappearance of Hahellaceae was observed.<br><br>CONCLUSION/SIGNIFICANCE: This is the first spatiotemporal study to investigate the bacterial diversity associated with a temperate shallow gorgonian. Our data revealed an established relationship between P. clavata and a specific bacterial group within the Oceanospirillales. These results suggest a potential symbiotic role of Hahellaceae in the host-microbe association, as recently suggested for tropical corals. However, a transient imbalance in bacterial associations can be tolerated by the holobiont without apparent symptoms of disease. The subsequent restoration of the Hahellaceae-dominated community is indicative of the specificity and resilience of the bacteria associated with the gorgonian host.}, }
@article {pmid23405104, year = {2013}, author = {Sammarco, PW and Strychar, KB}, title = {Responses to high seawater temperatures in zooxanthellate octocorals.}, journal = {PloS one}, volume = {8}, number = {2}, pages = {e54989}, doi = {10.1371/journal.pone.0054989}, pmid = {23405104}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*physiology ; Apoptosis/physiology ; Australia ; Hot Temperature ; Necrosis/physiopathology ; Seawater ; Symbiosis/physiology ; Temperature ; }, abstract = {Increases in Sea Surface Temperatures (SSTs) as a result of global warming have caused reef-building scleractinian corals to bleach worldwide, a result of the loss of obligate endosymbiotic zooxanthellae. Since the 1980's, bleaching severity and frequency has increased, in some cases causing mass mortality of corals. Earlier experiments have demonstrated that zooxanthellae in scleractinian corals from three families from the Great Barrier Reef, Australia (Faviidae, Poritidae, and Acroporidae) are more sensitive to heat stress than their hosts, exhibiting differential symptoms of programmed cell death - apoptosis and necrosis. Most zooxanthellar phylotypes are dying during expulsion upon release from the host. The host corals appear to be adapted or exapted to the heat increases. We attempt to determine whether this adaptation/exaptation occurs in octocorals by examining the heat-sensitivities of zooxanthellae and their host octocoral alcyonacean soft corals - Sarcophyton ehrenbergi (Alcyoniidae), Sinularia lochmodes (Alcyoniidae), and Xenia elongata (Xeniidae), species from two different families. The soft coral holobionts were subjected to experimental seawater temperatures of 28, 30, 32, 34, and 36°C for 48 hrs. Host and zooxanthellar cells were examined for viability, apoptosis, and necrosis (in hospite and expelled) using transmission electron microscopy (TEM), fluorescent microscopy (FM), and flow cytometry (FC). As experimental temperatures increased, zooxanthellae generally exhibited apoptotic and necrotic symptoms at lower temperatures than host cells and were expelled. Responses varied species-specifically. Soft coral hosts were adapted/exapted to higher seawater temperatures than their zooxanthellae. As with the scleractinians, the zooxanthellae appear to be the limiting factor for survival of the holobiont in the groups tested, in this region. These limits have now been shown to operate in six species within five families and two orders of the Cnidaria in the western Pacific. We hypothesize that this relationship may have taxonomic implications for other obligate zooxanthellate cnidarians subject to bleaching.}, }
@article {pmid23397797, year = {2012}, author = {Gilbert, SF and Sapp, J and Tauber, AI}, title = {A symbiotic view of life: we have never been individuals.}, journal = {The Quarterly review of biology}, volume = {87}, number = {4}, pages = {325-341}, pmid = {23397797}, issn = {0033-5770}, mesh = {Animals ; Humans ; *Symbiosis ; }, abstract = {The notion of the &quot;biological individual&quot; is crucial to studies of genetics, immunology, evolution, development, anatomy, and physiology. Each of these biological subdisciplines has a specific conception of individuality, which has historically provided conceptual contexts for integrating newly acquired data. During the past decade, nucleic acid analysis, especially genomic sequencing and high-throughput RNA techniques, has challenged each of these disciplinary definitions by finding significant interactions of animals and plants with symbiotic microorganisms that disrupt the boundaries that heretofore had characterized the biological individual. Animals cannot be considered individuals by anatomical or physiological criteria because a diversity of symbionts are both present and functional in completing metabolic pathways and serving other physiological functions. Similarly, these new studies have shown that animal development is incomplete without symbionts. Symbionts also constitute a second mode of genetic inheritance, providing selectable genetic variation for natural selection. The immune system also develops, in part, in dialogue with symbionts and thereby functions as a mechanism for integrating microbes into the animal-cell community. Recognizing the &quot;holobiont&quot;--the multicellular eukaryote plus its colonies of persistent symbionts--as a critically important unit of anatomy, development, physiology, immunology, and evolution opens up new investigative avenues and conceptually challenges the ways in which the biological subdisciplines have heretofore characterized living entities.}, }
@article {pmid23303369, year = {2013}, author = {Nelson, CE and Goldberg, SJ and Wegley Kelly, L and Haas, AF and Smith, JE and Rohwer, F and Carlson, CA}, title = {Coral and macroalgal exudates vary in neutral sugar composition and differentially enrich reef bacterioplankton lineages.}, journal = {The ISME journal}, volume = {7}, number = {5}, pages = {962-979}, doi = {10.1038/ismej.2012.161}, pmid = {23303369}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/chemistry/metabolism/*microbiology ; Bacteria/*classification/growth &amp; development/isolation &amp; purification/metabolism ; Carbohydrate Metabolism ; Carbon/metabolism ; Chlorophyta/chemistry/microbiology ; Coral Reefs ; Hydrogen-Ion Concentration ; Plankton/classification/growth &amp; development/isolation &amp; purification/metabolism ; Polynesia ; RNA, Ribosomal, 16S ; Rhodophyta/chemistry/microbiology ; Seawater/*chemistry/*microbiology ; Seaweed/chemistry/*microbiology ; }, abstract = {Increasing algal cover on tropical reefs worldwide may be maintained through feedbacks whereby algae outcompete coral by altering microbial activity. We hypothesized that algae and coral release compositionally distinct exudates that differentially alter bacterioplankton growth and community structure. We collected exudates from the dominant hermatypic coral holobiont Porites spp. and three dominant macroalgae (one each Ochrophyta, Rhodophyta and Chlorophyta) from reefs of Mo'orea, French Polynesia. We characterized exudates by measuring dissolved organic carbon (DOC) and fractional dissolved combined neutral sugars (DCNSs) and subsequently tracked bacterioplankton responses to each exudate over 48 h, assessing cellular growth, DOC/DCNS utilization and changes in taxonomic composition (via 16S rRNA amplicon pyrosequencing). Fleshy macroalgal exudates were enriched in the DCNS components fucose (Ochrophyta) and galactose (Rhodophyta); coral and calcareous algal exudates were enriched in total DCNS but in the same component proportions as ambient seawater. Rates of bacterioplankton growth and DOC utilization were significantly higher in algal exudate treatments than in coral exudate and control incubations with each community selectively removing different DCNS components. Coral exudates engendered the smallest shift in overall bacterioplankton community structure, maintained high diversity and enriched taxa from Alphaproteobacteria lineages containing cultured representatives with relatively few virulence factors (VFs) (Hyphomonadaceae and Erythrobacteraceae). In contrast, macroalgal exudates selected for less diverse communities heavily enriched in copiotrophic Gammaproteobacteria lineages containing cultured pathogens with increased VFs (Vibrionaceae and Pseudoalteromonadaceae). Our results demonstrate that algal exudates are enriched in DCNS components, foster rapid growth of bacterioplankton and select for bacterial populations with more potential VFs than coral exudates.}, }
@article {pmid23291051, year = {2013}, author = {Edge, SE and Shearer, TL and Morgan, MB and Snell, TW}, title = {Sub-lethal coral stress: detecting molecular responses of coral populations to environmental conditions over space and time.}, journal = {Aquatic toxicology (Amsterdam, Netherlands)}, volume = {128-129}, number = {}, pages = {135-146}, doi = {10.1016/j.aquatox.2012.11.014}, pmid = {23291051}, issn = {1879-1514}, mesh = {Alveolata/physiology ; Analysis of Variance ; Animals ; Anthozoa/*genetics/*metabolism ; *Ecosystem ; Environmental Monitoring ; Gene Expression Profiling ; *Gene Expression Regulation ; *Stress, Physiological ; Time Factors ; }, abstract = {In order for sessile organisms to survive environmental fluctuations and exposures to pollutants, molecular mechanisms (i.e. stress responses) are elicited. Previously, detrimental effects of natural and anthropogenic stressors on coral health could not be ascertained until significant physiological responses resulted in visible signs of stress (e.g. tissue necrosis, bleaching). In this study, a focused anthozoan holobiont microarray was used to detect early and sub-lethal effects of spatial and temporal environmental changes on gene expression patterns in the scleractinian coral, Montastraea cavernosa, on south Florida reefs. Although all colonies appeared healthy (i.e. no visible tissue necrosis or bleaching), corals were differentially physiologically compensating for exposure to stressors that varied over time. Corals near the Port of Miami inlet experienced significant changes in expression of stress responsive and symbiont (zooxanthella)-specific genes after periods of heavy precipitation. In contrast, coral populations did not demonstrate stress responses during periods of increased water temperature (up to 29°C). Specific acute and long-term localized responses to other stressors were also evident. A correlation between stress response genes and symbiont-specific genes was also observed, possibly indicating early processes involved in the maintenance or disruption of the coral-zooxanthella symbiosis. This is the first study to reveal spatially- and temporally-related variation in gene expression in response to different stressors of in situ coral populations, and demonstrates that microarray technology can be used to detect specific sub-lethal physiological responses to specific environmental conditions that are not visually detectable.}, }
@article {pmid23283017, year = {2013}, author = {Fan, L and Liu, M and Simister, R and Webster, NS and Thomas, T}, title = {Marine microbial symbiosis heats up: the phylogenetic and functional response of a sponge holobiont to thermal stress.}, journal = {The ISME journal}, volume = {7}, number = {5}, pages = {991-1002}, doi = {10.1038/ismej.2012.165}, pmid = {23283017}, issn = {1751-7370}, mesh = {Animals ; Bacteria/classification/*growth &amp; development/*metabolism ; *Climate Change ; Coral Reefs ; Ecosystem ; *Microbiota ; Phylogeny ; Porifera/*microbiology/physiology ; Seawater ; Symbiosis ; }, abstract = {Large-scale mortality of marine invertebrates is a major global concern for ocean ecosystems and many sessile, reef-building animals, such as sponges and corals, are experiencing significant declines through temperature-induced disease and bleaching. The health and survival of marine invertebrates is often dependent on intimate symbiotic associations with complex microbial communities, yet we have a very limited understanding of the detailed biology and ecology of both the host and the symbiont community in response to environmental stressors, such as elevated seawater temperatures. Here, we use the ecologically important sponge Rhopaloeides odorabile as a model to explore the changes in symbiosis during the development of temperature-induced necrosis. Expression profiling of the sponge host was examined in conjunction with the phylogenetic and functional structure and the expression profile of the symbiont community. Elevated temperature causes an immediate stress response in both the host and symbiont community, including reduced expression of functions that mediate their partnership. Disruption to nutritional interdependence and molecular interactions during early heat stress further destabilizes the holobiont, ultimately leading to the loss of archetypal sponge symbionts and the introduction of new microorganisms that have functional and expression profiles consistent with a scavenging lifestyle, a lack virulence functions and a high growth rate. Previous models have postulated various mechanisms of mortality and disease in marine invertebrates. Our study suggests that interruption of symbiotic interactions is a major determinant for mortality in marine sessile invertebrates. High symbiont specialization and low functional redundancy, thus make these holobionts extremely vulnerable to environmental perturbations, including climate change.}, }
@article {pmid23264045, year = {2013}, author = {Seemann, J and Sawall, Y and Auel, H and Richter, C}, title = {The use of lipids and fatty acids to measure the trophic plasticity of the coral Stylophora subseriata.}, journal = {Lipids}, volume = {48}, number = {3}, pages = {275-286}, doi = {10.1007/s11745-012-3747-1}, pmid = {23264045}, issn = {1558-9307}, mesh = {Acclimatization ; Animals ; Anthozoa/*physiology ; Autotrophic Processes ; Chlorophyll/metabolism ; Fatty Acids/*metabolism ; Heterotrophic Processes ; *Lipid Metabolism ; Plankton/physiology ; Symbiosis ; }, abstract = {Following up on previous investigations on the stress resistance of corals, this study assessed the trophic plasticity of the coral Stylophora subseriata in the Spermonde Archipelago (Indonesia) along an eutrophication gradient. Trophic plasticity was assessed in terms of lipid content and fatty acid composition in the holobiont relative to its plankton (50-300 μm) food as well as the zooxanthellae density, lipid, FA and chlorophyll a content. A cross-transplantation experiment was carried out for 1.5 months in order to assess the trophic potential of corals. Corals, which live in the eutrophied nearshore area showed higher zooxanthellae and chlorophyll a values and higher amounts of the dinoflagellate biomarker FA 18:4n-3. Their lipid contents were maintained at similar to levels from specimens further away from the anthropogenic impact source going up to 14.9 ± 0.9 %. A similarity percentage analysis of the groups holobiont, zooxanthellae and plankton >55 μm found that differences between the FA composition of the holobiont and zooxanthellae symbionts were more distinct in the site closer to the shore, thus heterotrophic feeding became more important. Transplanted corals attained very similar zooxanthellae, chlorophyll a and lipid values at all sites as the specimens originating from those sites, which indicates a high potential for trophic plasticity in the case of a change in food sources, which makes this species competitive and resistant to eutrophication.}, }
@article {pmid23254513, year = {2013}, author = {Krediet, CJ and Ritchie, KB and Alagely, A and Teplitski, M}, title = {Members of native coral microbiota inhibit glycosidases and thwart colonization of coral mucus by an opportunistic pathogen.}, journal = {The ISME journal}, volume = {7}, number = {5}, pages = {980-990}, doi = {10.1038/ismej.2012.164}, pmid = {23254513}, issn = {1751-7370}, mesh = {Acetylglucosaminidase/metabolism ; Animals ; Anthozoa/*microbiology/physiology ; *Antibiosis ; Bacillales/growth &amp; development/*metabolism ; Glycoside Hydrolases/metabolism ; Sea Anemones/microbiology ; Serratia marcescens/genetics/*growth &amp; development/metabolism/pathogenicity ; Symbiosis ; Virulence ; }, abstract = {The outcome of the interactions between native commensal microorganisms and opportunistic pathogens is crucial to the health of the coral holobiont. During the establishment within the coral surface mucus layer, opportunistic pathogens, including a white pox pathogen Serratia marcescens PDL100, compete with native bacteria for available nutrients. Both commensals and pathogens employ glycosidases and N-acetyl-glucosaminidase to utilize components of coral mucus. This study tested the hypothesis that specific glycosidases were critical for the growth of S. marcescens on mucus and that their inhibition by native coral microbiota reduces fitness of the pathogen. Consistent with this hypothesis, a S. marcescens transposon mutant with reduced glycosidase and N-acetyl-glucosaminidase activities was unable to compete with the wild type on the mucus of the host coral Acropora palmata, although it was at least as competitive as the wild type on a minimal medium with glycerol and casamino acids. Virulence of the mutant was modestly reduced in the Aiptasia model. A survey revealed that ∼8% of culturable coral commensal bacteria have the ability to inhibit glycosidases in the pathogen. A small molecular weight, ethanol-soluble substance(s) produced by the coral commensal Exiguobacterium sp. was capable of the inhibition of the induction of catabolic enzymes in S. marcescens. This inhibition was in part responsible for the 10-100-fold reduction in the ability of the pathogen to grow on coral mucus. These results provide insight into potential mechanisms of commensal interference with early colonization and infection behaviors in opportunistic pathogens and highlight an important function for the native microbiota in coral health.}, }
@article {pmid23174086, year = {2013}, author = {Cima, F and Ferrari, G and Ferreira, NG and Rocha, RJ and Serôdio, J and Loureiro, S and Calado, R}, title = {Preliminary evaluation of the toxic effects of the antifouling biocide Sea-Nine 211™ in the soft coral Sarcophyton cf. glaucum (Octocorallia, Alcyonacea) based on PAM fluorometry and biomarkers.}, journal = {Marine environmental research}, volume = {83}, number = {}, pages = {16-22}, doi = {10.1016/j.marenvres.2012.10.004}, pmid = {23174086}, issn = {1879-0291}, mesh = {Animals ; Anthozoa/*drug effects/metabolism ; Biomarkers/*analysis ; Disinfectants/*toxicity ; Enzyme Activation/drug effects ; *Fluorometry ; Microalgae/drug effects ; Photosynthesis/drug effects ; Thiazoles/*toxicity ; Toxicity Tests/standards ; }, abstract = {Sea-Nine 211™ is a new biocide specifically formulated for antifouling paints and being considered to have a low environmental impact. Even with a short environmental half-life, this compound can cause toxic effects on marine organisms. This study used PAM fluorometry and biomarkers of oxidative stress (GST, CAT and LPO) to monitor potential toxic effects of Sea-Nine 211™ on fragments of the soft coral Sarcophyton cf. glaucum. After exposure to concentrations of 1-100 μg l(-1) for 72 h, CAT activity was inhibited under the two highest concentrations, being in accordance with the activity of GST. LPO activity (as TBARS) and photosynthetic efficiency of endosymbiotic zooxanthellae were not significantly affected. These results show that PAM fluorometry alone cannot detect the full effects of Sea-Nine 211™ on Sarcophyton cf. glaucum and should be used together with other biomarkers. This holobiont driven approach to evaluate chemical toxicity in photosynthetic corals is therefore recommended for biocides which are not photosystem II inhibitors.}, }
@article {pmid23170223, year = {2012}, author = {Oliver, KR and Greene, WK}, title = {Transposable elements and viruses as factors in adaptation and evolution: an expansion and strengthening of the TE-Thrust hypothesis.}, journal = {Ecology and evolution}, volume = {2}, number = {11}, pages = {2912-2933}, doi = {10.1002/ece3.400}, pmid = {23170223}, issn = {2045-7758}, abstract = {In addition to the strong divergent evolution and significant and episodic evolutionary transitions and speciation we previously attributed to TE-Thrust, we have expanded the hypothesis to more fully account for the contribution of viruses to TE-Thrust and evolution. The concept of symbiosis and holobiontic genomes is acknowledged, with particular emphasis placed on the creativity potential of the union of retroviral genomes with vertebrate genomes. Further expansions of the TE-Thrust hypothesis are proposed regarding a fuller account of horizontal transfer of TEs, the life cycle of TEs, and also, in the case of a mammalian innovation, the contributions of retroviruses to the functions of the placenta. The possibility of drift by TE families within isolated demes or disjunct populations, is acknowledged, and in addition, we suggest the possibility of horizontal transposon transfer into such subpopulations. &quot;Adaptive potential&quot; and &quot;evolutionary potential&quot; are proposed as the extremes of a continuum of &quot;intra-genomic potential&quot; due to TE-Thrust. Specific data is given, indicating &quot;adaptive potential&quot; being realized with regard to insecticide resistance, and other insect adaptations. In this regard, there is agreement between TE-Thrust and the concept of adaptation by a change in allele frequencies. Evidence on the realization of &quot;evolutionary potential&quot; is also presented, which is compatible with the known differential survivals, and radiations of lineages. Collectively, these data further suggest the possibility, or likelihood, of punctuated episodes of speciation events and evolutionary transitions, coinciding with, and heavily underpinned by, intermittent bursts of TE activity.}, }
@article {pmid23157386, year = {2013}, author = {Egan, S and Harder, T and Burke, C and Steinberg, P and Kjelleberg, S and Thomas, T}, title = {The seaweed holobiont: understanding seaweed-bacteria interactions.}, journal = {FEMS microbiology reviews}, volume = {37}, number = {3}, pages = {462-476}, doi = {10.1111/1574-6976.12011}, pmid = {23157386}, issn = {1574-6976}, mesh = {Bacteria/metabolism/pathogenicity ; *Bacterial Physiological Phenomena ; *Biodiversity ; *Host-Pathogen Interactions ; *Metagenome ; Seaweed/*microbiology ; *Symbiosis ; }, abstract = {Seaweeds (macroalgae) form a diverse and ubiquitous group of photosynthetic organisms that play an essential role in aquatic ecosystems. These ecosystem engineers contribute significantly to global primary production and are the major habitat formers on rocky shores in temperate waters, providing food and shelter for aquatic life. Like other eukaryotic organisms, macroalgae harbor a rich diversity of associated microorganisms with functions related to host health and defense. In particular, epiphytic bacterial communities have been reported as essential for normal morphological development of the algal host, and bacteria with antifouling properties are thought to protect chemically undefended macroalgae from detrimental, secondary colonization by other microscopic and macroscopic epibiota. This tight relationship suggests that macroalgae and epiphytic bacteria interact as a unified functional entity or holobiont, analogous to the previously suggested relationship in corals. Moreover, given that the impact of diseases in marine ecosystems is apparently increasing, understanding the role of bacteria as saprophytes and pathogens in seaweed communities may have important implications for marine management strategies. This review reports on the recent advances in the understanding of macroalgal-bacterial interactions with reference to the diversity and functional role of epiphytic bacteria in maintaining algal health, highlighting the holobiont concept.}, }
@article {pmid23145489, year = {2012}, author = {Ladner, JT and Barshis, DJ and Palumbi, SR}, title = {Protein evolution in two co-occurring types of Symbiodinium: an exploration into the genetic basis of thermal tolerance in Symbiodinium clade D.}, journal = {BMC evolutionary biology}, volume = {12}, number = {}, pages = {217}, doi = {10.1186/1471-2148-12-217}, pmid = {23145489}, issn = {1471-2148}, mesh = {Acclimatization/*genetics ; Animals ; Anthozoa/*microbiology ; Biological Evolution ; Climate Change ; Coral Reefs ; Dinoflagellida/*genetics ; *Hot Temperature ; *Symbiosis ; Transcriptome ; }, abstract = {BACKGROUND: The symbiosis between reef-building corals and photosynthetic dinoflagellates (Symbiodinium) is an integral part of the coral reef ecosystem, as corals are dependent on Symbiodinium for the majority of their energy needs. However, this partnership is increasingly at risk due to changing climatic conditions. It is thought that functional diversity within Symbiodinium may allow some corals to rapidly adapt to different environments by changing the type of Symbiodinium with which they partner; however, very little is known about the molecular basis of the functional differences among symbiont groups. One group of Symbiodinium that is hypothesized to be important for the future of reefs is clade D, which, in general, seems to provide the coral holobiont (i.e., coral host and associated symbiont community) with elevated thermal tolerance. Using high-throughput sequencing data from field-collected corals we assembled, de novo, draft transcriptomes for Symbiodinium clades C and D. We then explore the functional basis of thermal tolerance in clade D by comparing rates of coding sequence evolution among the four clades of Symbiodinium most commonly found in reef-building corals (A-D).<br><br>RESULTS: We are able to highlight a number of genes and functional categories as candidates for involvement in the increased thermal tolerance of clade D. These include a fatty acid desaturase, molecular chaperones and proteins involved in photosynthesis and the thylakoid membrane. We also demonstrate that clades C and D co-occur within most of the sampled colonies of Acropora hyacinthus, suggesting widespread potential for this coral species to acclimatize to changing thermal conditions via 'shuffling' the proportions of these two clades from within their current symbiont communities.<br><br>CONCLUSIONS: Transcriptome-wide analysis confirms that the four main Symbiodinium clades found within corals exhibit extensive evolutionary divergence (18.5-27.3% avg. pairwise nucleotide difference). Despite these evolutionary distinctions, many corals appear to host multiple clades simultaneously, which may allow for rapid acclimatization to changing environmental conditions. This study provides a first step toward understanding the molecular basis of functional differences between Symbiodinium clades by highlighting a number of genes with signatures consistent with positive selection along the thermally tolerant clade D lineage.}, }
@article {pmid23133637, year = {2012}, author = {Cardoso, AM and Cavalcante, JJ and Cantão, ME and Thompson, CE and Flatschart, RB and Glogauer, A and Scapin, SM and Sade, YB and Beltrão, PJ and Gerber, AL and Martins, OB and Garcia, ES and de Souza, W and Vasconcelos, AT}, title = {Metagenomic analysis of the microbiota from the crop of an invasive snail reveals a rich reservoir of novel genes.}, journal = {PloS one}, volume = {7}, number = {11}, pages = {e48505}, doi = {10.1371/journal.pone.0048505}, pmid = {23133637}, issn = {1932-6203}, mesh = {Animals ; Biofuels ; Biomass ; Biotechnology/methods ; Carbohydrates/chemistry ; Carbon Dioxide/chemistry ; Computational Biology/methods ; Ethanol/chemistry ; Glycoside Hydrolases/chemistry ; Lignin/chemistry ; Metagenome ; *Metagenomics ; Oligosaccharides/chemistry ; Petroleum/metabolism ; Phylogeny ; Protein Binding ; Sequence Analysis, DNA/methods ; Snails ; }, abstract = {The shortage of petroleum reserves and the increase in CO(2) emissions have raised global concerns and highlighted the importance of adopting sustainable energy sources. Second-generation ethanol made from lignocellulosic materials is considered to be one of the most promising fuels for vehicles. The giant snail Achatina fulica is an agricultural pest whose biotechnological potential has been largely untested. Here, the composition of the microbial population within the crop of this invasive land snail, as well as key genes involved in various biochemical pathways, have been explored for the first time. In a high-throughput approach, 318 Mbp of 454-Titanium shotgun metagenomic sequencing data were obtained. The predominant bacterial phylum found was Proteobacteria, followed by Bacteroidetes and Firmicutes. Viruses, Fungi, and Archaea were present to lesser extents. The functional analysis reveals a variety of microbial genes that could assist the host in the degradation of recalcitrant lignocellulose, detoxification of xenobiotics, and synthesis of essential amino acids and vitamins, contributing to the adaptability and wide-ranging diet of this snail. More than 2,700 genes encoding glycoside hydrolase (GH) domains and carbohydrate-binding modules were detected. When we compared GH profiles, we found an abundance of sequences coding for oligosaccharide-degrading enzymes (36%), very similar to those from wallabies and giant pandas, as well as many novel cellulase and hemicellulase coding sequences, which points to this model as a remarkable potential source of enzymes for the biofuel industry. Furthermore, this work is a major step toward the understanding of the unique genetic profile of the land snail holobiont.}, }
@article {pmid23014479, year = {2013}, author = {Al-Dahash, LM and Mahmoud, HM}, title = {Harboring oil-degrading bacteria: a potential mechanism of adaptation and survival in corals inhabiting oil-contaminated reefs.}, journal = {Marine pollution bulletin}, volume = {72}, number = {2}, pages = {364-374}, doi = {10.1016/j.marpolbul.2012.08.029}, pmid = {23014479}, issn = {1879-3363}, mesh = {*Adaptation, Physiological ; Animals ; Anthozoa/*physiology ; Bacteria/classification/genetics/*metabolism ; Biodegradation, Environmental ; Biodiversity ; *Coral Reefs ; Petroleum/*metabolism ; Petroleum Pollution/statistics &amp; numerical data ; Phylogeny ; Symbiosis ; Water Pollutants, Chemical/*metabolism ; }, abstract = {Certain coral reef systems north of the Arabian Gulf are characterized by corals with a unique ability to thrive and flourish despite the presence of crude oil continuously seeping from natural cracks in the seabed. Harboring oil-degrading bacteria as a part of the holobiont has been investigated as a potential mechanism of adaptation and survival for corals in such systems. The use of conventional and molecular techniques verified a predominance of bacteria affiliated with Gammaproteobacteria, Actinobacteria and Firmicutes in the mucus and tissues of Acropora clathrata and Porites compressa. These bacteria were capable of degrading a wide range of aliphatic (C9-C28) aromatic hydrocarbons (Phenanthrene, Biphenyl, Naphthalene) and crude oil. In addition, microcosms supplied with coral samples and various concentrations of crude oil shifted their bacterial population toward the more advantageous types of oil degraders as oil concentrations increased.}, }
@article {pmid23011286, year = {2013}, author = {Meron, D and Buia, MC and Fine, M and Banin, E}, title = {Changes in microbial communities associated with the sea anemone Anemonia viridis in a natural pH gradient.}, journal = {Microbial ecology}, volume = {65}, number = {2}, pages = {269-276}, doi = {10.1007/s00248-012-0127-6}, pmid = {23011286}, issn = {1432-184X}, mesh = {Animals ; Bacteria/genetics/*isolation &amp; purification ; *Biota ; Carbon Dioxide/analysis ; Chlorophyll/analysis ; DNA, Bacterial/genetics ; Dinoflagellida/isolation &amp; purification ; *Hydrogen-Ion Concentration ; Italy ; Mediterranean Sea ; Proton-Motive Force ; Sea Anemones/*microbiology ; Seawater/chemistry ; }, abstract = {Ocean acidification, resulting from rising atmospheric carbon dioxide concentrations, is a pervasive stressor that can affect many marine organisms and their symbionts. Studies which examine the host physiology and microbial communities have shown a variety of responses to the ocean acidification process. Recently, several studies were conducted based on field experiments, which take place in natural CO(2) vents, exposing the host to natural environmental conditions of varying pH. This study examines the sea anemone Anemonia viridis which is found naturally along the pH gradient in Ischia, Italy, with an aim to characterize whether exposure to pH impacts the holobiont. The physiological parameters of A. viridis (Symbiodinium density, protein, and chlorophyll a+c concentration) and its microbial community were monitored. Although reduction in pH was seen to have had an impact on composition and diversity of associated microbial communities, no significant changes were observed in A. viridis physiology, and no microbial stress indicators (i.e., pathogens, antibacterial activity, etc.) were detected. In light of these results, it appears that elevated CO(2) does not have a negative influence on A. viridis that live naturally in the site. This suggests that natural long-term exposure and dynamic diverse microbial communities may contribute to the acclimation process of the host in a changing pH environment.}, }
@article {pmid22985125, year = {2012}, author = {de Oliveira, LS and Gregoracci, GB and Silva, GG and Salgado, LT and Filho, GA and Alves-Ferreira, M and Pereira, RC and Thompson, FL}, title = {Transcriptomic analysis of the red seaweed Laurencia dendroidea (Florideophyceae, Rhodophyta) and its microbiome.}, journal = {BMC genomics}, volume = {13}, number = {}, pages = {487}, doi = {10.1186/1471-2164-13-487}, pmid = {22985125}, issn = {1471-2164}, mesh = {Cyanobacteria/*genetics/metabolism ; DNA, Complementary/biosynthesis ; Expressed Sequence Tags ; Laurencia/*genetics/metabolism/microbiology ; Metabolic Networks and Pathways/genetics ; *Metagenome ; Photosynthesis ; Proteobacteria/*genetics/metabolism ; Seaweed/*genetics/metabolism/microbiology ; Sequence Analysis, DNA ; Symbiosis ; Terpenes/metabolism ; *Transcriptome ; }, abstract = {BACKGROUND: Seaweeds of the Laurencia genus have a broad geographic distribution and are largely recognized as important sources of secondary metabolites, mainly halogenated compounds exhibiting diverse potential pharmacological activities and relevant ecological role as anti-epibiosis. Host-microbe interaction is a driving force for co-evolution in the marine environment, but molecular studies of seaweed-associated microbial communities are still rare. Despite the large amount of research describing the chemical compositions of Laurencia species, the genetic knowledge regarding this genus is currently restricted to taxonomic markers and general genome features. In this work we analyze the transcriptomic profile of L. dendroidea J. Agardh, unveil the genes involved on the biosynthesis of terpenoid compounds in this seaweed and explore the interactions between this host and its associated microbiome.<br><br>RESULTS: A total of 6 transcriptomes were obtained from specimens of L. dendroidea sampled in three different coastal locations of the Rio de Janeiro state. Functional annotations revealed predominantly basic cellular metabolic pathways. Bacteria was the dominant active group in the microbiome of L. dendroidea, standing out nitrogen fixing Cyanobacteria and aerobic heterotrophic Proteobacteria. The analysis of the relative contribution of each domain highlighted bacterial features related to glycolysis, lipid and polysaccharide breakdown, and also recognition of seaweed surface and establishment of biofilm. Eukaryotic transcripts, on the other hand, were associated with photosynthesis, synthesis of carbohydrate reserves, and defense mechanisms, including the biosynthesis of terpenoids through the mevalonate-independent pathway.<br><br>CONCLUSIONS: This work describes the first transcriptomic profile of the red seaweed L. dendroidea, increasing the knowledge about ESTs from the Florideophyceae algal class. Our data suggest an important role for L. dendroidea in the primary production of the holobiont and the role of Bacteria as consumers of organic matter and possibly also as nitrogen source. Furthermore, this seaweed expressed sequences related to terpene biosynthesis, including the complete mevalonate-independent pathway, which offers new possibilities for biotechnological applications using secondary metabolites from L. dendroidea.}, }
@article {pmid22983034, year = {2012}, author = {Bosch, TC}, title = {What hydra has to say about the role and origin of symbiotic interactions.}, journal = {The Biological bulletin}, volume = {223}, number = {1}, pages = {78-84}, doi = {10.1086/BBLv223n1p78}, pmid = {22983034}, issn = {1939-8697}, mesh = {Animals ; Bacteria/growth &amp; development ; *Bacterial Physiological Phenomena ; Chlorella/growth &amp; development/*physiology ; Genomics/methods ; Hydra/*microbiology/*physiology ; Metabolomics/methods ; Proteomics/methods ; *Symbiosis ; Toll-Like Receptors/metabolism ; }, abstract = {The Hydra holobiont involves at least three types of organisms that all share a long coevolutionary history and appear to depend on each other. Here I review how symbiotic algae and stably associated bacteria interact with the Hydra host and where in the tissue they are located. In particular I discuss the role of Toll-like receptor (TLR) signaling in maintaining Hydra's species-specific microbiota. I also discuss studies in Hydra viridis and its symbiotic Chlorella algae which indicate that the symbiotic algae are critically involved in the control of sexual differentiation in green Hydra. Finally, I review the state of &quot;omics&quot; in this tripartite association and the fact that the functioning of this holobiont is also a tale of several genomes.}, }
@article {pmid22944243, year = {2012}, author = {Barott, KL and Rohwer, FL}, title = {Unseen players shape benthic competition on coral reefs.}, journal = {Trends in microbiology}, volume = {20}, number = {12}, pages = {621-628}, doi = {10.1016/j.tim.2012.08.004}, pmid = {22944243}, issn = {1878-4380}, mesh = {Animals ; Anthozoa/*microbiology/virology ; Bacteria/growth &amp; development ; *Biota ; *Coral Reefs ; *Microbial Interactions ; Organic Chemicals/metabolism ; Population Dynamics ; Seawater/microbiology/virology ; Seaweed/growth &amp; development/metabolism ; Viruses/growth &amp; development ; }, abstract = {Recent work has shown that hydrophilic and hydrophobic organic matter (OM) from algae disrupts the function of the coral holobiont and promotes the invasion of opportunistic pathogens, leading to coral morbidity and mortality. Here we refer to these dynamics as the (3)DAM [dissolved organic matter (DOM), direct contact, disease, algae and microbes] model. There is considerable complexity in coral-algae interactions; turf algae and macroalgae promote heterotrophic microbial overgrowth of coral, macroalgae also directly harm the corals via hydrophobic OM, whereas crustose coralline algae generally encourage benign microbial communities. In addition, complex flow patterns transport OM and pathogens from algae to downstream corals, and direct algal contact enhances their delivery. These invisible players (microbes, viruses, and OM) are important drivers of coral reefs because they have non-linear responses to disturbances and are the first to change in response to perturbations, providing near real-time trajectories for a coral reef, a vital metric for conservation and restoration.}, }
@article {pmid22933373, year = {2012}, author = {Putnam, HM and Stat, M and Pochon, X and Gates, RD}, title = {Endosymbiotic flexibility associates with environmental sensitivity in scleractinian corals.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1746}, pages = {4352-4361}, doi = {10.1098/rspb.2012.1454}, pmid = {22933373}, issn = {1471-2954}, mesh = {Animals ; Anthozoa/*parasitology/*physiology ; Climate Change ; Dinoflagellida/classification/*genetics/physiology ; Ecosystem ; Environment ; Molecular Sequence Data ; Phylogeny ; Polynesia ; Sequence Analysis, DNA ; Species Specificity ; *Symbiosis ; }, abstract = {Flexibility in biological systems is seen as an important driver of macro-ecosystem function and stability. Spatially constrained endosymbiotic settings, however, are less studied, although environmental thresholds of symbiotic corals are linked to the function of their endosymbiotic dinoflagellate communities. Symbiotic flexibility is a hypothesized mechanism that corals may exploit to adapt to climate change. This study explores the flexibility of the coral-Symbiodinium symbiosis through quantification of Symbiodinium ITS2 sequence assemblages in a range of coral species and genera. Sequence assemblages are expressed as an index of flexibility incorporating phylogenetic divergence and relative abundance of Symbiodinium sequences recovered from the host. This comparative analysis reveals profound differences in the flexibility of corals for Symbiodinium, thereby classifying corals as generalists or specifists. Generalists such as Acropora and Pocillopora exhibit high intra- and inter-species flexibility in their Symbiodinium assemblages and are some of the most environmentally sensitive corals. Conversely, specifists such as massive Porites colonies exhibit low flexibility, harbour taxonomically narrow Symbiodinium assemblages, and are environmentally resistant corals. Collectively, these findings challenge the paradigm that symbiotic flexibility enhances holobiont resilience. This underscores the need for a deeper examination of the extent and duration of the functional benefits associated with endosymbiotic diversity and flexibility under environmental stress.}, }
@article {pmid22919645, year = {2012}, author = {Salvucci, E}, title = {Selfishness, warfare, and economics; or integration, cooperation, and biology.}, journal = {Frontiers in cellular and infection microbiology}, volume = {2}, number = {}, pages = {54}, doi = {10.3389/fcimb.2012.00054}, pmid = {22919645}, issn = {2235-2988}, mesh = {Biology/*trends ; *Evolution, Molecular ; Humans ; }, abstract = {The acceptance of Darwin's theory of evolution by natural selection is not complete and it has been pointed out its limitation to explain the complex processes that constitute the transformation of species. It is necessary to discuss the explaining power of the dominant paradigm. It is common that new discoveries bring about contradictions that are intended to be overcome by adjusting results to the dominant reductionist paradigm using all sorts of gradations and combinations that are admitted for each case. In addition to the discussion on the validity of natural selection, modern findings represent a challenge to the interpretation of the observations with the Darwinian view of competition and struggle for life as theoretical basis. New holistic interpretations are emerging related to the Net of Life, in which the interconnection of ecosystems constitutes a dynamic and self-regulating biosphere: viruses are recognized as a macroorganism with a huge collection of genes, most unknown that constitute the major planet's gene pool. They play a fundamental role in evolution since their sequences are capable of integrating into the genomes in an &quot;infective&quot; way and become an essential part of multicellular organisms. They have content with &quot;biological sense&quot; i.e., they appear as part of normal life processes and have a serious role as carrier elements of complex genetic information. Antibiotics are cell signals with main effects on general metabolism and transcription on bacterial cells and communities. The hologenome theory considers an organism and all of its associated symbiotic microbes (parasites, mutualists, synergists, amensalists) as a result of symbiopoiesis. Microbes, helmints, that are normally understood as parasites are cohabitants and they have cohabited with their host and drive the evolution and existence of the partners. Each organism is the result of integration of complex systems. The eukaryotic organism is the result of combination of bacterial, virus, and eukaryotic DNA and it is the result of the interaction of its own genome with the genome of its microbiota, and their metabolism are intertwined (as a &quot;superorganism&quot;) along evolution. The darwinian paradigm had its origin in the free market theories and concepts of Malthus and Spencer. Then, nature was explained on the basis of market theories moving away from an accurate explanation of natural phenomena. It is necessary to acknowledge the limitations of the dominant dogma. These new interpretations about biological processes, molecules, roles of viruses in nature, and microbial interactions are remarkable points to be considered in order to construct a solid theory adjusted to the facts and with less speculations and tortuous semantic traps.}, }
@article {pmid22906221, year = {2013}, author = {del Campo, EM and Catalá, S and Gimeno, J and del Hoyo, A and Martínez-Alberola, F and Casano, LM and Grube, M and Barreno, E}, title = {The genetic structure of the cosmopolitan three-partner lichen Ramalina farinacea evidences the concerted diversification of symbionts.}, journal = {FEMS microbiology ecology}, volume = {83}, number = {2}, pages = {310-323}, doi = {10.1111/j.1574-6941.2012.01474.x}, pmid = {22906221}, issn = {1574-6941}, mesh = {Ascomycota/classification/*genetics/isolation &amp; purification ; Chlorophyta/classification/*genetics ; Europe ; Genetic Variation ; Genotype ; Lichens/classification/*genetics/isolation &amp; purification ; Nucleic Acid Conformation ; Phylogeny ; RNA, Ribosomal/chemistry ; Spain ; Symbiosis/*genetics ; }, abstract = {The epiphytic lichen Ramalina farinacea is distributed throughout the northern hemisphere in which the same two algal Trebouxia species (provisionally named TR1 and TR9) coexist in every thallus. Ramalina farinacea symbionts were characterized based on the two fungal nuclear loci (nrITS and rpb2) along with the primary and secondary structures of nrITS from each Trebouxia species in the Iberian Peninsula and Canary Islands. The results indicated a noticeable genetic differentiation between mycobionts from these two geographic areas and also suggested concerted changes in the three partners of a lichen symbiosis toward two clearly distinguishable 'holobiont' lineages. Modeling of ITS2 RNA secondary structures suggested their temperature sensitivity in TR1 but not in TR9, which was consistent with the observed superior physiological performance of TR9 phycobionts under relatively high temperatures. Both TR1 and TR9 phycobionts have been also found in a variety of taxonomically distinct lichens with a preferably Mediterranean distribution, being TR1 much more widespread than TR9. Our observations support a model in which ecological diversification and speciation of lichen symbionts in different habitats could include a transient phase consisting of associations with more than one photobiont in individual thalli. Such diversification is likely to be promoted by different physiological backgrounds.}, }
@article {pmid22895828, year = {2013}, author = {Ceh, J and van Keulen, M and Bourne, DG}, title = {Intergenerational transfer of specific bacteria in corals and possible implications for offspring fitness.}, journal = {Microbial ecology}, volume = {65}, number = {1}, pages = {227-231}, doi = {10.1007/s00248-012-0105-z}, pmid = {22895828}, issn = {1432-184X}, mesh = {Animals ; Anthozoa/*microbiology/physiology ; Bacteria/*classification/genetics/isolation &amp; purification ; Biodiversity ; DNA, Bacterial/genetics ; Germ Cells/*microbiology ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Seawater/*microbiology ; Sequence Analysis, DNA ; }, abstract = {Diverse and abundant bacterial populations play important functional roles in the multi-partite association of the coral holobiont. The specificity of coral-associated assemblages remains unclear, and little is known about the inheritance of specific bacteria from the parent colony to their offspring. This study investigated if broadcast spawning and brooding corals release specific and potentially beneficial bacteria with their offspring to secure maintenance across generations. Two coral species, Acropora tenuis and Pocillopora damicornis, were maintained in 0.2 μm filtered seawater during the release of their gametes and planulae, respectively. Water samples, excluding gametes and planulae, were subsequently collected, and bacterial diversity was assessed through a pyrosequencing approach amplifying a 470-bp region of the 16S rRNA gene including the variable regions 1-3. Compared to the high bacterial diversity harboured by corals, only a few taxa of bacteria were released by adult corals. Both A. tenuis and P. damicornis released similar bacteria, and the genera Alteromonas and Roseobacter were abundant in large proportions in the seawater of both species after reproduction. This study suggests that adult corals may release bacteria with their offspring to benefit the fitness in early coral life stages.}, }
@article {pmid22877610, year = {2012}, author = {Stat, M and Baker, AC and Bourne, DG and Correa, AM and Forsman, Z and Huggett, MJ and Pochon, X and Skillings, D and Toonen, RJ and van Oppen, MJ and Gates, RD}, title = {Molecular delineation of species in the coral holobiont.}, journal = {Advances in marine biology}, volume = {63}, number = {}, pages = {1-65}, doi = {10.1016/B978-0-12-394282-1.00001-6}, pmid = {22877610}, issn = {0065-2881}, mesh = {Animals ; Anthozoa/*classification/genetics/*physiology ; *Biodiversity ; Climate Change ; *Coral Reefs ; *Genetic Speciation ; }, abstract = {The coral holobiont is a complex assemblage of organisms spanning a diverse taxonomic range including a cnidarian host, as well as various dinoflagellate, prokaryotic and acellular symbionts. With the accumulating information on the molecular diversity of these groups, binomial species classification and a reassessment of species boundaries for the partners in the coral holobiont is a logical extension of this work and will help enhance the capacity for comparative research among studies. To aid in this endeavour, we review the current literature on species diversity for the three best studied partners of the coral holobiont (coral, Symbiodinium, prokaryotes) and provide suggestions for future work on systematics within these taxa. We advocate for an integrative approach to the delineation of species using both molecular genetics in combination with phenetic characters. We also suggest that an a priori set of criteria be developed for each taxonomic group as no one species concept or accompanying set of guidelines is appropriate for delineating all members of the coral holobiont.}, }
@article {pmid22864853, year = {2013}, author = {Lins-de-Barros, MM and Cardoso, AM and Silveira, CB and Lima, JL and Clementino, MM and Martins, OB and Albano, RM and Vieira, RP}, title = {Microbial community compositional shifts in bleached colonies of the Brazilian reef-building coral Siderastrea stellata.}, journal = {Microbial ecology}, volume = {65}, number = {1}, pages = {205-213}, doi = {10.1007/s00248-012-0095-x}, pmid = {22864853}, issn = {1432-184X}, mesh = {Animals ; Anthozoa/*microbiology ; Archaea/*classification/genetics ; Bacteria/*classification/genetics ; Brazil ; Chlorophyta/classification/*genetics ; DNA Barcoding, Taxonomic ; DNA, Algal/genetics ; DNA, Archaeal/genetics ; DNA, Bacterial/genetics ; Diatoms/classification/genetics ; Ecosystem ; Gene Library ; Phylogeny ; Plastids/genetics ; RNA, Ribosomal, 16S/genetics ; Rhodophyta/*classification/genetics ; Symbiosis ; }, abstract = {The association of metazoan, protist, and microbial communities with Scleractinian corals forms the basis of the coral holobiont. Coral bleaching events have been occurring around the world, introducing changes in the delicate balance of the holobiont symbiotic interactions. In this study, Archaea, bacteria, and eukaryotic phototrophic plastids of bleached colonies of the Brazilian coral Siderastrea stellata were analyzed for the first time, using 16S rRNA gene libraries. Prokaryotic communities were slightly more diverse in healthy than in bleached corals. However, the eukaryotic phototrophic plastids community was more diverse in bleached corals. Archaea phylogenetic analyses revealed a high percentage of Crenarchaeota sequences, mainly related to Nitrosopumilus maritimus and Cenarchaeum symbiosum. Dramatic changes in bacterial community composition were observed in this bleaching episode. The dominant bacterial group was Alphaproteobacteria followed by Gammaproteobacteria in bleached and Betaproteobacteria in healthy samples. Plastid operational taxonomic units (OTUs) from both coral samples were mainly related to red algae chloroplasts (Florideophycea), but we also observed some OTUs related to green algae chloroplasts (Chlorophyta). There seems to be a strong relationship between the Bacillariophyta phylum and our bleached coral samples as clones related to members of the diatom genera Amphora and Nitzschia were detected. The present study reveals information from a poorly investigated coral species and improves the knowledge of coral microbial community shifts that could occur during bleaching episodes.}, }
@article {pmid22822369, year = {2012}, author = {Hunt, LR and Smith, SM and Downum, KR and Mydlarz, LD}, title = {Microbial regulation in gorgonian corals.}, journal = {Marine drugs}, volume = {10}, number = {6}, pages = {1225-1243}, doi = {10.3390/md10061225}, pmid = {22822369}, issn = {1660-3397}, mesh = {Animals ; Anthozoa/*chemistry/*microbiology ; Anti-Bacterial Agents/*chemistry/*pharmacology ; Bacteria/*drug effects ; Cell Communication/drug effects ; Florida ; Puerto Rico ; Quorum Sensing/*drug effects ; }, abstract = {Gorgonian corals possess many novel natural products that could potentially mediate coral-bacterial interactions. Since many bacteria use quorum sensing (QS) signals to facilitate colonization of host organisms, regulation of prokaryotic cell-to-cell communication may represent an important bacterial control mechanism. In the present study, we examined extracts of twelve species of Caribbean gorgonian corals, for mechanisms that regulate microbial colonization, such as antibacterial activity and QS regulatory activity. Ethanol extracts of gorgonians collected from Puerto Rico and the Florida Keys showed a range of both antibacterial and QS activities using a specific Pseudomonas aeruginosa QS reporter, sensitive to long chain AHLs and a short chain N-acylhomoserine lactones (AHL) biosensor, Chromobacterium violaceium. Overall, the gorgonian corals had higher antimicrobial activity against non-marine strains when compared to marine strains. Pseudopterogorgia americana, Pseusopterogorgia acerosa, and Pseudoplexuara flexuosa had the highest QS inhibitory effect. Interestingly, Pseudoplexuara porosa extracts stimulated QS activity with a striking 17-fold increase in signal. The stimulation of QS by P. porosa or other elements of the holobiont may encourage colonization or recruitment of specific microbial species. Overall, these results suggest the presence of novel stimulatory QS, inhibitory QS and bactericidal compounds in gorgonian corals. A better understanding of these compounds may reveal insight into coral-microbial ecology and whether a therapeutic potential exists.}, }
@article {pmid22773636, year = {2012}, author = {Morrow, KM and Moss, AG and Chadwick, NE and Liles, MR}, title = {Bacterial associates of two Caribbean coral species reveal species-specific distribution and geographic variability.}, journal = {Applied and environmental microbiology}, volume = {78}, number = {18}, pages = {6438-6449}, doi = {10.1128/AEM.01162-12}, pmid = {22773636}, issn = {1098-5336}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/*classification/*isolation &amp; purification ; *Biota ; Caribbean Region ; DNA Barcoding, Taxonomic ; DNA Fingerprinting ; Denaturing Gradient Gel Electrophoresis ; Host-Parasite Interactions ; *Phylogeography ; Ribotyping ; }, abstract = {Scleractinian corals harbor microorganisms that form dynamic associations with the coral host and exhibit substantial genetic and ecological diversity. Microbial associates may provide defense against pathogens and serve as bioindicators of changing environmental conditions. Here we describe the bacterial assemblages associated with two of the most common and phylogenetically divergent reef-building corals in the Caribbean, Montastraea faveolata and Porites astreoides. Contrasting life history strategies and disease susceptibilities indicate potential differences in their microbiota and immune function that may in part drive changes in the composition of coral reef communities. The ribotype structure and diversity of coral-associated bacteria within the surface mucosal layer (SML) of healthy corals were assessed using denaturing gradient gel electrophoresis (DGGE) fingerprinting and 454 bar-coded pyrosequencing. Corals were sampled at disparate Caribbean locations representing various levels of anthropogenic impact. We demonstrate here that M. faveolata and P. astreoides harbor distinct, host-specific bacteria but that specificity varies by species and site. P. astreoides generally hosts a bacterial assemblage of low diversity that is largely dominated by one bacterial genus, Endozoicomonas, within the order Oceanospirillales. The bacterial assemblages associated with M. faveolata are significantly more diverse and exhibit higher specificity at the family level than P. astreoides assemblages. Both corals have more bacterial diversity and higher abundances of disease-related bacteria at sites closer to the mainland than at those furthest away. The most diverse bacterial taxa and highest relative abundance of disease-associated bacteria were seen for corals near St. Thomas, U.S. Virgin Islands (USVI) (2.5 km from shore), and the least diverse taxa and lowest relative abundance were seen for corals near our most pristine site in Belize (20 km from shore). We conclude that the two coral species studied harbor distinct bacterial assemblages within the SML, but the degree to which each species maintains specific microbial associations varies both within each site and across large spatial scales. The taxonomic scale (i.e., phylum versus genus) at which scientists examine coral-microbe associations, in addition to host-elicited factors and environmental fluctuations, must be considered carefully in future studies of the coral holobiont.}, }
@article {pmid22767125, year = {2012}, author = {Shnit-Orland, M and Sivan, A and Kushmaro, A}, title = {Antibacterial activity of Pseudoalteromonas in the coral holobiont.}, journal = {Microbial ecology}, volume = {64}, number = {4}, pages = {851-859}, doi = {10.1007/s00248-012-0086-y}, pmid = {22767125}, issn = {1432-184X}, mesh = {Animals ; Anthozoa/*microbiology ; *Antibiosis ; DNA, Bacterial/analysis/genetics ; *Ecosystem ; Gram-Negative Bacteria/genetics/growth &amp; development/isolation &amp; purification ; Gram-Positive Bacteria/genetics/*growth &amp; development/isolation &amp; purification ; Indian Ocean ; Israel ; Microbial Sensitivity Tests/methods ; Microbial Viability ; Phylogeny ; Pseudoalteromonas/classification/genetics/growth &amp; development/*isolation &amp; purification ; Sequence Analysis, DNA ; Staphylococcus aureus/genetics/growth &amp; development ; Symbiosis ; }, abstract = {Corals harbor diverse and abundant prokaryotic populations. Bacterial communities residing in the coral mucus layer may be either pathogenic or symbiotic. Some species may produce antibiotics as a method of controlling populations of competing microbial species. The present study characterizes cultivable Pseudoalteromonas sp. isolated from the mucus layer of different coral species from the northern Gulf of Eilat, Red Sea, Israel. Six mucus-associated Pseudoalteromonas spp. obtained from different coral species were screened for antibacterial activity against 23 tester strains. Five of the six Pseudoalteromonas strains demonstrated extracellular antibacterial activity against Gram-positive-but not Gram-negative-tester strains. Active substances secreted into the cell-free supernatant are heat-tolerant and inhibit growth of Bacillus cereus, Staphylococcus aureus, and of ten endogenous Gram-positive marine bacteria isolated from corals. The Pseudoalteromonas spp. isolated from Red sea corals aligned in a phylogenetic tree with previously isolated Pseudoalteromonas spp. of marine origin that demonstrated antimicrobial activity. These results suggest that coral mucus-associated Pseudoalteromonas may play a protective role in the coral holobiont's defense against potential Gram-positive coral pathogens.}, }
@article {pmid22701613, year = {2012}, author = {White, JR and Patel, J and Ottesen, A and Arce, G and Blackwelder, P and Lopez, JV}, title = {Pyrosequencing of bacterial symbionts within Axinella corrugata sponges: diversity and seasonal variability.}, journal = {PloS one}, volume = {7}, number = {6}, pages = {e38204}, doi = {10.1371/journal.pone.0038204}, pmid = {22701613}, issn = {1932-6203}, mesh = {Animals ; Bacteria/*genetics ; Base Sequence ; *Biodiversity ; Cluster Analysis ; Computational Biology ; Florida ; Microscopy, Electron, Transmission ; Molecular Sequence Data ; Phylogeny ; Porifera/*microbiology/ultrastructure ; Principal Component Analysis ; RNA, Ribosomal, 16S/genetics ; *Seasons ; Sequence Analysis, DNA ; Species Specificity ; *Symbiosis ; }, abstract = {BACKGROUND: Marine sponge species are of significant interest to many scientific fields including marine ecology, conservation biology, genetics, host-microbe symbiosis and pharmacology. One of the most intriguing aspects of the sponge &quot;holobiont&quot; system is the unique physiology, interaction with microbes from the marine environment and the development of a complex commensal microbial community. However, intraspecific variability and temporal stability of sponge-associated bacterial symbionts remain relatively unknown.<br><br>We have characterized the bacterial symbiont community biodiversity of seven different individuals of the Caribbean reef sponge Axinella corrugata, from two different Florida reef locations during variable seasons using multiplex 454 pyrosequencing of 16 S rRNA amplicons. Over 265,512 high-quality 16 S rRNA sequences were generated and analyzed. Utilizing versatile bioinformatics methods and analytical software such as the QIIME and CloVR packages, we have identified 9,444 distinct bacterial operational taxonomic units (OTUs). Approximately 65,550 rRNA sequences (24%) could not be matched to bacteria at the class level, and may therefore represent novel taxa. Differentially abundant classes between seasonal Axinella communities included Gammaproteobacteria, Flavobacteria, Alphaproteobacteria, Cyanobacteria, Acidobacter and Nitrospira. Comparisons with a proximal outgroup sponge species (Amphimedon compressa), and the growing sponge symbiont literature, indicate that this study has identified approximately 330 A. corrugata-specific symbiotic OTUs, many of which are related to the sulfur-oxidizing Ectothiorhodospiraceae. This family appeared exclusively within A. corrugata, comprising >34.5% of all sequenced amplicons. Other A. corrugata symbionts such as Deltaproteobacteria, Bdellovibrio, and Thiocystis among many others are described.<br><br>CONCLUSIONS/SIGNIFICANCE: Slight shifts in several bacterial taxa were observed between communities sampled during spring and fall seasons. New 16 S rDNA sequences and concomitant identifications greatly expand the microbial community profile for this model reef sponge, and will likely be useful as a baseline for any future comparisons regarding sponge microbial community dynamics.}, }
@article {pmid22688725, year = {2012}, author = {Bosch, TC}, title = {Understanding complex host-microbe interactions in Hydra.}, journal = {Gut microbes}, volume = {3}, number = {4}, pages = {345-351}, doi = {10.4161/gmic.20660}, pmid = {22688725}, issn = {1949-0984}, mesh = {Animals ; Bacteria/*pathogenicity ; *Host-Pathogen Interactions ; Hydra/*microbiology ; Models, Animal ; }, abstract = {Any multicellular organism may be considered a metaorganism or holobiont-comprised of the macroscopic host and synergistic interdependence with bacteria, archaea, fungi, viruses, and numerous other microbial and eukaryotic species including algal symbionts. Defining the individual microbe-host conversations in these consortia is a challenging but necessary step on the path to understanding the function of the associations as a whole. Dissecting the fundamental principles that underlie all host-microbe interactions requires simple animal models with only a few specific bacterial species. Here I present Hydra as such a model with one of the simplest epithelia in the animal kingdom, with the availability of a fully sequenced genome and numerous genomic tools, and with few associated bacterial species.}, }
@article {pmid22552233, year = {2012}, author = {Seveso, D and Montano, S and Strona, G and Orlandi, I and Vai, M and Galli, P}, title = {Up-regulation of Hsp60 in response to skeleton eroding band disease but not by algal overgrowth in the scleractinian coral Acropora muricata.}, journal = {Marine environmental research}, volume = {78}, number = {}, pages = {34-39}, doi = {10.1016/j.marenvres.2012.03.008}, pmid = {22552233}, issn = {1879-0291}, mesh = {Animals ; Anthozoa/*metabolism ; Biomarkers/metabolism ; Chaperonin 60/*biosynthesis ; Plant Development ; Protozoan Infections, Animal/*metabolism ; Stress, Physiological/*physiology ; Up-Regulation ; }, abstract = {Heat shock proteins are biomarkers commonly used to determine the effects of abiotic stresses on the physiology of reef building corals. In this study the effectiveness of the Hsp60 as indicator of biotic stresses in the scleractinian coral Acropora muricata was analyzed, considering the whole holobiont. We focused on two biological interactions recognized to be important contributors to coral reef degradation such as a coral disease, the Skeleton eroding band (SEB) caused by the protozoan Halofolliculina corallasia and the algal overgrowth. In the lagoon of Magoodhoo Island (Maldives) fragments of living tissue of A. muricata exposed to these biotic factors were sampled and proteins subjected to Western analysis. The two different biological interactions trigger diverse responses on Hsp60 level. No detectable effect on Hsp60 modulation appeared in colonies subjected to algal overgrowth. On the contrary, corals displayed a robust up-regulation of Hsp60 in the fragments sampled just above the SEB dark band, where the level of Hsp60 was almost twice compared to the control colonies, indicating that the aggressive behavior of the protozoan causes cellular damage also in coral portions neighboring and along the advancing front of the infection. Portions of coral sampled distant to the SEB band showed a Hsp60 level comparable to that observed in healthy colonies. We propose Hsp60 expression as a promising tool to evaluate physiological stress caused by SEB disease in reef corals.}, }
@article {pmid22527059, year = {2012}, author = {Harder, T and Campbell, AH and Egan, S and Steinberg, PD}, title = {Chemical mediation of ternary interactions between marine holobionts and their environment as exemplified by the red alga Delisea pulchra.}, journal = {Journal of chemical ecology}, volume = {38}, number = {5}, pages = {442-450}, doi = {10.1007/s10886-012-0119-5}, pmid = {22527059}, issn = {1573-1561}, mesh = {Bacterial Physiological Phenomena ; *Ecosystem ; Furans/metabolism ; Herbivory ; Rhodophyta/metabolism/*physiology ; }, abstract = {The need for animals and plants to control microbial colonization is important in the marine environment with its high densities of microscopic propagules and seawater that provides an ideal medium for their dispersal. In contrast to the traditional emphasis on antagonistic interactions of marine organisms with microbes, emerging studies lend support to the notion that health and performance of many marine organisms are functionally regulated and assisted by associated microbes, an ecological concept defined as a holobiont. While antimicrobial activities of marine secondary metabolites have been studied in great depth ex-situ, we are beginning to understand how some of these compounds function in an ecological context to maintain the performance of marine holobionts. The present article reviews two decades of our research on the red seaweed Delisea pulchra by addressing: the defense chemistry of this seaweed; chemically-mediated interactions between the seaweed and its natural enemies; and the negative influence of elevated seawater temperature on these interactions. Our understanding of these defense compounds and the functional roles they play for D. pulchra extends from molecular interactions with bacterial cell signaling molecules, to ecosystem-scale consequences of chemically-controlled disease and herbivory. Delisea pulchra produces halogenated furanones that antagonize the same receptor as acylated homoserine lactones (AHL)-a group of widespread intercellular communication signals among bacteria. Halogenated furanones compete with and inhibit bacterial cell-to-cell communication, and thus interfere with important bacterial communication-regulated processes, such as biofilm formation. In a predictable pattern that occurs at the ecological level of entire populations, environmental stress interferes with the production of halogenated furanones, causing downstream processes that ultimately result in disease of the algal holobiont.}, }
@article {pmid22438932, year = {2012}, author = {Cardoso, AM and Cavalcante, JJ and Vieira, RP and Lima, JL and Grieco, MA and Clementino, MM and Vasconcelos, AT and Garcia, ES and de Souza, W and Albano, RM and Martins, OB}, title = {Gut bacterial communities in the giant land snail Achatina fulica and their modification by sugarcane-based diet.}, journal = {PloS one}, volume = {7}, number = {3}, pages = {e33440}, doi = {10.1371/journal.pone.0033440}, pmid = {22438932}, issn = {1932-6203}, mesh = {Animals ; Bacteria/classification/genetics/isolation &amp; purification ; Base Sequence ; DNA Primers/genetics ; DNA, Bacterial/genetics ; Diet ; Digestive System/microbiology ; Ecosystem ; Humans ; *Metagenome ; Phylogeny ; Saccharum ; Snails/*microbiology/pathogenicity ; }, abstract = {The invasive land snail Achatina fulica is one of the most damaging agricultural pests worldwide representing a potentially serious threat to natural ecosystems and human health. This species is known to carry parasites and harbors a dense and metabolically active microbial community; however, little is known about its diversity and composition. Here, we assessed for the first time the complexity of bacterial communities occurring in the digestive tracts of field-collected snails (FC) by using culture-independent molecular analysis. Crop and intestinal bacteria in FC were then compared to those from groups of snails that were reared in the laboratory (RL) on a sugarcane-based diet. Most of the sequences recovered were novel and related to those reported for herbivorous gut. Changes in the relative abundance of Bacteroidetes and Firmicutes were observed when the snails were fed a high-sugar diet, suggesting that the snail gut microbiota can influence the energy balance equation. Furthermore, this study represents a first step in gaining a better understanding of land snail gut microbiota and shows that this is a complex holobiont system containing diverse, abundant and active microbial communities.}, }
@article {pmid22437157, year = {2012}, author = {Meron, D and Rodolfo-Metalpa, R and Cunning, R and Baker, AC and Fine, M and Banin, E}, title = {Changes in coral microbial communities in response to a natural pH gradient.}, journal = {The ISME journal}, volume = {6}, number = {9}, pages = {1775-1785}, doi = {10.1038/ismej.2012.19}, pmid = {22437157}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/classification/genetics ; *Bacterial Physiological Phenomena ; *Biodiversity ; Hydrogen-Ion Concentration ; Metagenome/genetics/*physiology ; Phylogeny ; RNA, Ribosomal, 16S/genetics ; Seawater/*chemistry ; }, abstract = {Surface seawater pH is currently 0.1 units lower than pre-industrial values and is projected to decrease by up to 0.4 units by the end of the century. This acidification has the potential to cause significant perturbations to the physiology of ocean organisms, particularly those such as corals that build their skeletons/shells from calcium carbonate. Reduced ocean pH could also have an impact on the coral microbial community, and thus may affect coral physiology and health. Most of the studies to date have examined the impact of ocean acidification on corals and/or associated microbiota under controlled laboratory conditions. Here we report the first study that examines the changes in coral microbial communities in response to a natural pH gradient (mean pH(T) 7.3-8.1) caused by volcanic CO(2) vents off Ischia, Gulf of Naples, Italy. Two Mediterranean coral species, Balanophyllia europaea and Cladocora caespitosa, were examined. The microbial community diversity and the physiological parameters of the endosymbiotic dinoflagellates (Symbiodinium spp.) were monitored. We found that pH did not have a significant impact on the composition of associated microbial communities in both coral species. In contrast to some earlier studies, we found that corals present at the lower pH sites exhibited only minor physiological changes and no microbial pathogens were detected. Together, these results provide new insights into the impact of ocean acidification on the coral holobiont.}, }
@article {pmid22344646, year = {2012}, author = {Lema, KA and Willis, BL and Bourne, DG}, title = {Corals form characteristic associations with symbiotic nitrogen-fixing bacteria.}, journal = {Applied and environmental microbiology}, volume = {78}, number = {9}, pages = {3136-3144}, doi = {10.1128/AEM.07800-11}, pmid = {22344646}, issn = {1098-5336}, mesh = {Animals ; Anthozoa/*microbiology/physiology ; Australia ; Bacteria/*classification/genetics/*isolation &amp; purification/metabolism ; Bacterial Physiological Phenomena ; *Biodiversity ; Cluster Analysis ; DNA, Bacterial/chemistry/genetics ; Molecular Sequence Data ; *Nitrogen Fixation ; Oxidoreductases/genetics ; Phylogeny ; Sequence Analysis, DNA ; *Symbiosis ; }, abstract = {The complex symbiotic relationship between corals and their dinoflagellate partner Symbiodinium is believed to be sustained through close associations with mutualistic bacterial communities, though little is known about coral associations with bacterial groups able to fix nitrogen (diazotrophs). In this study, we investigated the diversity of diazotrophic bacterial communities associated with three common coral species (Acropora millepora, Acropora muricata, and Pocillopora damicormis) from three midshelf locations of the Great Barrier Reef (GBR) by profiling the conserved subunit of the nifH gene, which encodes the dinitrogenase iron protein. Comparisons of diazotrophic community diversity among coral tissue and mucus microenvironments and the surrounding seawater revealed that corals harbor diverse nifH phylotypes that differ between tissue and mucus microhabitats. Coral mucus nifH sequences displayed high heterogeneity, and many bacterial groups overlapped with those found in seawater. Moreover, coral mucus diazotrophs were specific neither to coral species nor to reef location, reflecting the ephemeral nature of coral mucus. In contrast, the dominant diazotrophic bacteria in tissue samples differed among coral species, with differences remaining consistent at all three reefs, indicating that coral-diazotroph associations are species specific. Notably, dominant diazotrophs for all coral species were closely related to the bacterial group rhizobia, which represented 71% of the total sequences retrieved from tissue samples. The species specificity of coral-diazotroph associations further supports the coral holobiont model that bacterial groups associated with corals are conserved. Our results suggest that, as in terrestrial plants, rhizobia have developed a mutualistic relationship with corals and may contribute fixed nitrogen to Symbiodinium.}, }
@article {pmid22335606, year = {2012}, author = {Ribes, M and Jiménez, E and Yahel, G and López-Sendino, P and Diez, B and Massana, R and Sharp, JH and Coma, R}, title = {Functional convergence of microbes associated with temperate marine sponges.}, journal = {Environmental microbiology}, volume = {14}, number = {5}, pages = {1224-1239}, doi = {10.1111/j.1462-2920.2012.02701.x}, pmid = {22335606}, issn = {1462-2920}, mesh = {Animals ; Bacteria/*classification/genetics/metabolism ; *Bacterial Physiological Phenomena ; Carbon/metabolism ; Mediterranean Sea ; Microbial Consortia/*physiology ; Molecular Sequence Data ; Nitrogen/metabolism ; *Phylogeny ; Porifera/*microbiology ; RNA, Ribosomal, 16S/genetics ; Symbiosis ; }, abstract = {Most marine sponges establish a persistent association with a wide array of phylogenetically and physiologically diverse microbes. To date, the role of these symbiotic microbial communities in the metabolism and nutrient cycles of the sponge-microbe consortium remains largely unknown. We identified and quantified the microbial communities associated with three common Mediterranean sponge species, Dysidea avara, Agelas oroides and Chondrosia reniformis (Demospongiae) that cohabitate coralligenous community. For each sponge we quantified the uptake and release of dissolved organic carbon (DOC) and nitrogen (DON), inorganic nitrogen and phosphate. Low microbial abundance and no evidence for DOC uptake or nitrification were found for D. avara. In contrast A. oroides and C. reniformis showed high microbial abundance (30% and 70% of their tissue occupied by microbes respectively) and both species exhibited high nitrification and high DOC and NH(4) (+) uptake. Surprisingly, these unique metabolic pathways were mediated in each sponge species by a different, and host specific, microbial community. The functional convergence of microbial consortia found in these two sympatric sponge species, suggest that these metabolic processes may be of special relevance to the success of the holobiont.}, }
@article {pmid22226071, year = {2012}, author = {Patowary, A and Chauhan, RK and Singh, M and Kv, S and Periwal, V and Kp, K and Sapkal, GN and Bondre, VP and Gore, MM and Sivasubbu, S and Scaria, V}, title = {De novo identification of viral pathogens from cell culture hologenomes.}, journal = {BMC research notes}, volume = {5}, number = {}, pages = {11}, doi = {10.1186/1756-0500-5-11}, pmid = {22226071}, issn = {1756-0500}, abstract = {BACKGROUND: Fast, specific identification and surveillance of pathogens is the cornerstone of any outbreak response system, especially in the case of emerging infectious diseases and viral epidemics. This process is generally tedious and time-consuming thus making it ineffective in traditional settings. The added complexity in these situations is the non-availability of pure isolates of pathogens as they are present as mixed genomes or hologenomes. Next-generation sequencing approaches offer an attractive solution in this scenario as it provides adequate depth of sequencing at fast and affordable costs, apart from making it possible to decipher complex interactions between genomes at a scale that was not possible before. The widespread application of next-generation sequencing in this field has been limited by the non-availability of an efficient computational pipeline to systematically analyze data to delineate pathogen genomes from mixed population of genomes or hologenomes.<br><br>FINDINGS: We applied next-generation sequencing on a sample containing mixed population of genomes from an epidemic with appropriate processing and enrichment. The data was analyzed using an extensive computational pipeline involving mapping to reference genome sets and de-novo assembly. In depth analysis of the data generated revealed the presence of sequences corresponding to Japanese encephalitis virus. The genome of the virus was also independently de-novo assembled. The presence of the virus was in addition, verified using standard molecular biology techniques.<br><br>CONCLUSIONS: Our approach can accurately identify causative pathogens from cell culture hologenome samples containing mixed population of genomes and in principle can be applied to patient hologenome samples without any background information. This methodology could be widely applied to identify and isolate pathogen genomes and understand their genomic variability during outbreaks.}, }
@article {pmid22127887, year = {2012}, author = {Augustin, R and Fraune, S and Franzenburg, S and Bosch, TC}, title = {Where simplicity meets complexity: hydra, a model for host-microbe interactions.}, journal = {Advances in experimental medicine and biology}, volume = {710}, number = {}, pages = {71-81}, doi = {10.1007/978-1-4419-5638-5_8}, pmid = {22127887}, issn = {0065-2598}, mesh = {Animals ; Antimicrobial Cationic Peptides/immunology ; *Biological Evolution ; Genome ; *Host-Pathogen Interactions ; Humans ; Hydra/classification/immunology/*microbiology/physiology ; Immunity, Innate/immunology ; Phylogeny ; }, abstract = {For a long time, the main purpose of microbiology and immunology was to study pathogenic bacteria and infectious disease; the potential benefit of commensal bacteria remained unrecognised. Discovering that individuals from Hydra to man are not solitary, homogenous entities but consist of complex communities of many species that likely evolved during a billion years of coexistence (Fraune and Bosch 2010) led to the hologenome theory of evolution (Zilber-Rosenberg and Rosenberg 2008) which considers the holobiont with its hologenome as the unit of selection in evolution. Defining the individual microbe-host conversations in these consortia is a challenging but necessary step on the path to understanding the function of the associations as a whole. Untangling the complex interactions requires simple animal models with only a few specific bacterial species. Such models can function as living test tubes and may be key to dissecting the fundamental principles that underlie all host-microbe interactions. Here we introduce Hydra (Bosch et al. 2009) as such a model with one of the simplest epithelia in the animal kingdom (only two cell layers), with few cell types derived from only three distinct stem cell lineages, and with the availability of a fully sequenced genome and numerous genomic tools including transgenesis. Recognizing the entire system with its inputs, outputs and the interconnections (Fraune and Bosch 2010; Bosch et al. 2009; Fraune and Bosch 2007; Fraune et al. 2009a) we here present observations which may have profound impact on understanding a strictly microbe-dependent life style and its evolutionary consequences.}, }
@article {pmid23761367, year = {2011}, author = {Webster, NS and Botté, ES and Soo, RM and Whalan, S}, title = {The larval sponge holobiont exhibits high thermal tolerance.}, journal = {Environmental microbiology reports}, volume = {3}, number = {6}, pages = {756-762}, doi = {10.1111/j.1758-2229.2011.00296.x}, pmid = {23761367}, issn = {1758-2229}, abstract = {Marine sponges are critical components of benthic environments; however, their sessile habit, requirement to filter large volumes of water and complex symbiotic partnerships make them particularly vulnerable to the effects of global climate change. We assessed the effect of elevated seawater temperature on bacterial communities in larvae of the Great Barrier Reef sponge, Rhopaloeides odorabile. In contrast to the strict thermal threshold of 32°C previously identified in adult R. odorabile, larvae exhibit a markedly higher thermal tolerance, with no adverse health effects detected at temperatures below 36°C. Similarly, larval microbial communities were conserved at temperatures up to 34°C with a highly significant shift occurring after 24 h at 36°C. This shift involved the loss of previously described symbionts (in particular the Nitrospira, Chloroflexi and a Roseobacter lineage) and the appearance of new Gammaproteobacteria not detected at lower temperatures. Here, we demonstrated that sponge larvae maintain highly stable symbioses at seawater temperatures exceeding those that are predicted under current climate change scenarios. In addition, by revealing that the shift in microbial composition occurs in conjunction with necrosis and mortality of larvae at 36°C we have provided additional evidence of the strong link between host health and the stability of symbiont communities.}, }
@article {pmid23761353, year = {2011}, author = {Littman, R and Willis, BL and Bourne, DG}, title = {Metagenomic analysis of the coral holobiont during a natural bleaching event on the Great Barrier Reef.}, journal = {Environmental microbiology reports}, volume = {3}, number = {6}, pages = {651-660}, doi = {10.1111/j.1758-2229.2010.00234.x}, pmid = {23761353}, issn = {1758-2229}, abstract = {Understanding the effects of elevated seawater temperatures on each member of the coral holobiont (the complex comprised of coral polyps and associated symbiotic microorganisms, including Bacteria, viruses, Fungi, Archaea and endolithic algae) is becoming increasingly important as evidence accumulates that microbial members contribute to overall coral health, particularly during thermal stress. Here we use a metagenomic approach to identify metabolic and taxonomic shifts in microbial communities associated with the hard coral Acropora millepora throughout a natural thermal bleaching event at Magnetic Island (Great Barrier Reef). A direct comparison of metagenomic data sets from healthy versus bleached corals indicated major shifts in microbial associates during heat stress, including Bacteria, Archaea, viruses, Fungi and micro-algae. Overall, metabolism of the microbial community shifted from autotrophy to heterotrophy, including increases in genes associated with the metabolism of fatty acids, proteins, simple carbohydrates, phosphorus and sulfur. In addition, the proportion of virulence genes was higher in the bleached library, indicating an increase in microorganisms capable of pathogenesis following bleaching. These results demonstrate that thermal stress results in shifts in coral-associated microbial communities that may lead to deteriorating coral health.}, }
@article {pmid22046302, year = {2011}, author = {Mayfield, AB and Wang, LH and Tang, PC and Fan, TY and Hsiao, YY and Tsai, CL and Chen, CS}, title = {Assessing the impacts of experimentally elevated temperature on the biological composition and molecular chaperone gene expression of a reef coral.}, journal = {PloS one}, volume = {6}, number = {10}, pages = {e26529}, doi = {10.1371/journal.pone.0026529}, pmid = {22046302}, issn = {1932-6203}, mesh = {Animals ; Anthozoa/*genetics/physiology ; DNA/isolation &amp; purification ; Gene Expression Regulation/*physiology ; HSP70 Heat-Shock Proteins/analysis/genetics ; *Hot Temperature ; Molecular Chaperones/analysis/*genetics ; Proteins/analysis ; RNA/isolation &amp; purification ; Temperature ; }, abstract = {Due to the potential for increasing ocean temperatures to detrimentally impact reef-building corals, there is an urgent need to better understand not only the coral thermal stress response, but also natural variation in their sub-cellular composition. To address this issue, while simultaneously developing a molecular platform for studying one of the most common Taiwanese reef corals, Seriatopora hystrix, 1,092 cDNA clones were sequenced and characterized. Subsequently, RNA, DNA and protein were extracted sequentially from colonies exposed to elevated (30°C) temperature for 48 hours. From the RNA phase, a heat shock protein-70 (hsp70)-like gene, deemed hsp/c, was identified in the coral host, and expression of this gene was measured with real-time quantitative PCR (qPCR) in both the host anthozoan and endosymbiotic dinoflagellates (genus Symbiodinium). While mRNA levels were not affected by temperature in either member, hsp/c expression was temporally variable in both and co-varied within biopsies. From the DNA phase, host and Symbiodinium hsp/c genome copy proportions (GCPs) were calculated to track changes in the biological composition of the holobiont during the experiment. While there was no temperature effect on either host or Symbiodinium GCP, both demonstrated significant temporal variation. Finally, total soluble protein was responsive to neither temperature nor exposure time, though the protein/DNA ratio varied significantly over time. Collectively, it appears that time, and not temperature, is a more important driver of the variation in these parameters, highlighting the need to consider natural variation in both gene expression and the molecular make-up of coral holobionts when conducting manipulative studies. This represents the first study to survey multiple macromolecules from both compartments of an endosymbiotic organism with methodologies that reflect their dual-compartmental nature, ideally generating a framework for assessing molecular-level changes within corals and other endosymbioses exposed to changes in their environment.}, }
@article {pmid21984347, year = {2012}, author = {Kvennefors, EC and Sampayo, E and Kerr, C and Vieira, G and Roff, G and Barnes, AC}, title = {Regulation of bacterial communities through antimicrobial activity by the coral holobiont.}, journal = {Microbial ecology}, volume = {63}, number = {3}, pages = {605-618}, doi = {10.1007/s00248-011-9946-0}, pmid = {21984347}, issn = {1432-184X}, mesh = {Animals ; Anthozoa/chemistry/*metabolism/*microbiology/physiology ; Anti-Bacterial Agents/*metabolism ; Bacteria/classification/genetics/growth &amp; development/*isolation &amp; purification ; Bacterial Physiological Phenomena ; *Biodiversity ; Mucus/chemistry/metabolism ; Phylogeny ; }, abstract = {Interactions between corals and associated bacteria and amongst these bacterial groups are likely to play a key role in coral health. However, the complexity of these interactions is poorly understood. We investigated the functional role of specific coral-associated bacteria in maintaining microbial communities on the coral Acropora millepora (Ehrenberg 1834) and the ability of coral mucus to support or inhibit bacterial growth. Culture-independent techniques were used to assess bacterial community structures whilst bacterial culture was employed to assess intra- and inter-specific antimicrobial activities of bacteria. Members of Pseudoalteromonas and ribotypes closely related to Vibrio coralliilyticus displayed potent antimicrobial activity against a range of other cultured isolates and grew readily on detached coral mucus. Although such bacterial ribotypes would be expected to have a competitive advantage, they were rare or absent on intact and healthy coral colonies growing in situ (analysed using denaturing gradient gel electrophoresis and 16S rRNA gene sequencing). The most abundant bacterial ribotypes found on healthy corals were Gammaproteobacteria, previously defined as type A coral associates. Our results indicate that this group of bacteria and specific members of the Alphaproteobacteria described here as 'type B associates' may be important functional groups for coral health. We suggest that bacterial communities on coral are kept in check by a combination of host-derived and microbial interactions and that the type A associates in particular may play a key role in maintaining stability of microbial communities on healthy coral colonies.}, }
@article {pmid21976690, year = {2012}, author = {Bellantuono, AJ and Hoegh-Guldberg, O and Rodriguez-Lanetty, M}, title = {Resistance to thermal stress in corals without changes in symbiont composition.}, journal = {Proceedings. Biological sciences}, volume = {279}, number = {1731}, pages = {1100-1107}, doi = {10.1098/rspb.2011.1780}, pmid = {21976690}, issn = {1471-2954}, mesh = {*Acclimatization ; Alveolata/genetics/physiology ; Animals ; Anthozoa/genetics/microbiology/*physiology ; Climate Change ; Coral Reefs ; Genotype ; Oceans and Seas ; *Stress, Physiological ; *Symbiosis ; *Temperature ; }, abstract = {Discovering how corals can adjust their thermal sensitivity in the context of global climate change is important in understanding the long-term persistence of coral reefs. In this study, we showed that short-term preconditioning to higher temperatures, 3°C below the experimentally determined bleaching threshold, for a period of 10 days provides thermal tolerance for the symbiosis stability between the scleractinian coral, Acropora millepora and Symbiodinium. Based on genotypic analysis, our results indicate that the acclimatization of this coral species to thermal stress does not come down to simple changes in Symbiodinium and/or the bacterial communities that associate with reef-building corals. This suggests that the physiological plasticity of the host and/or symbiotic components appears to play an important role in responding to ocean warming. The further study of host and symbiont physiology, both of Symbiodinium and prokaryotes, is of paramount importance in the context of global climate change, as mechanisms for rapid holobiont acclimatization will become increasingly important to the long-standing persistence of coral reefs.}, }
@article {pmid21955993, year = {2012}, author = {Cárdenas, A and Rodriguez-R, LM and Pizarro, V and Cadavid, LF and Arévalo-Ferro, C}, title = {Shifts in bacterial communities of two Caribbean reef-building coral species affected by white plague disease.}, journal = {The ISME journal}, volume = {6}, number = {3}, pages = {502-512}, doi = {10.1038/ismej.2011.123}, pmid = {21955993}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/*classification/genetics/isolation &amp; purification ; Colombia ; Coral Reefs ; DNA, Bacterial/genetics ; DNA, Ribosomal/chemistry ; *Metagenome ; RNA, Ribosomal, 16S/genetics ; Sequence Analysis, DNA ; }, abstract = {Coral reefs are deteriorating at an alarming rate mainly as a consequence of the emergence of coral diseases. The white plague disease (WPD) is the most prevalent coral disease in the southwestern Caribbean, affecting dozens of coral species. However, the identification of a single causal agent has proved problematic. This suggests more complex etiological scenarios involving alterations in the dynamic interaction between environmental factors, the coral immune system and the symbiotic microbial communities. Here we compare the microbiome of healthy and WPD-affected corals from the two reef-building species Diploria strigosa and Siderastrea siderea collected at the Tayrona National Park in the Caribbean of Colombia. Microbiomes were analyzed by combining culture-dependent methods and pyrosequencing of 16S ribosomal DNA (rDNA) V5-V6 hypervariable regions. A total of 20,410 classifiable 16S rDNA sequences reads were obtained including all samples. No significant differences in operational taxonomic unit diversity were found between healthy and affected tissues; however, a significant increase of Alphaproteobacteria and a concomitant decrease in the Beta- and Gammaproteobacteria was observed in WPD-affected corals of both species. Significant shifts were also observed in the orders Rhizobiales, Caulobacteriales, Burkholderiales, Rhodobacterales, Aleteromonadales and Xanthomonadales, although they were not consistent between the two coral species. These shifts in the microbiome structure of WPD-affected corals suggest a loss of community-mediated growth control mechanisms on bacterial populations specific for each holobiont system.}, }
@article {pmid21949755, year = {2011}, author = {Riegl, BM and Purkis, SJ and Al-Cibahy, AS and Abdel-Moati, MA and Hoegh-Guldberg, O}, title = {Present limits to heat-adaptability in corals and population-level responses to climate extremes.}, journal = {PloS one}, volume = {6}, number = {9}, pages = {e24802}, doi = {10.1371/journal.pone.0024802}, pmid = {21949755}, issn = {1932-6203}, mesh = {*Adaptation, Physiological ; Animal Migration ; Animals ; Anthozoa/*physiology ; *Climate Change ; Decision Making ; Environment ; *Hot Temperature ; Indian Ocean ; Models, Biological ; Population Dynamics ; Species Specificity ; Time Factors ; Tropical Climate ; Water ; }, abstract = {Climate change scenarios suggest an increase in tropical ocean temperature by 1-3°C by 2099, potentially killing many coral reefs. But Arabian/Persian Gulf corals already exist in this future thermal environment predicted for most tropical reefs and survived severe bleaching in 2010, one of the hottest years on record. Exposure to 33-35°C was on average twice as long as in non-bleaching years. Gulf corals bleached after exposure to temperatures above 34°C for a total of 8 weeks of which 3 weeks were above 35°C. This is more heat than any other corals can survive, providing an insight into the present limits of holobiont adaptation. We show that average temperatures as well as heat-waves in the Gulf have been increasing, that coral population levels will fluctuate strongly, and reef-building capability will be compromised. This, in combination with ocean acidification and significant local threats posed by rampant coastal development puts even these most heat-adapted corals at risk. WWF considers the Gulf ecoregion as &quot;critically endangered&quot;. We argue here that Gulf corals should be considered for assisted migration to the tropical Indo-Pacific. This would have the double benefit of avoiding local extinction of the world's most heat-adapted holobionts while at the same time introducing their genetic information to populations naïve to such extremes, potentially assisting their survival. Thus, the heat-adaptation acquired by Gulf corals over 6 k, could benefit tropical Indo-Pacific corals who have <100 y until they will experience a similarly harsh climate. Population models suggest that the heat-adapted corals could become dominant on tropical reefs within ∼20 years.}, }
@article {pmid21804354, year = {2011}, author = {Sharon, G and Segal, D and Zilber-Rosenberg, I and Rosenberg, E}, title = {Symbiotic bacteria are responsible for diet-induced mating preference in Drosophila melanogaster, providing support for the hologenome concept of evolution.}, journal = {Gut microbes}, volume = {2}, number = {3}, pages = {190-192}, pmid = {21804354}, issn = {1949-0984}, mesh = {Animals ; Bacteria/*genetics/isolation &amp; purification ; *Biological Evolution ; Drosophila melanogaster/genetics/microbiology/*physiology ; Feeding Behavior ; Female ; Gastrointestinal Tract/*microbiology ; Genome ; Humans ; Male ; *Mating Preference, Animal ; *Metagenome ; Models, Animal ; *Symbiosis ; }, abstract = {Diet-induced mating preference in Drosophila melanogaster results from amplification of the commensal bacterium Lactobacillus plantarum, providing a new role for gut microbiota and support for the hologenome concept of evolution. When the flies were treated with antibiotics prior to changing their diet, mating preference did not occur. These data also indicate that other potentially beneficial bacteria could be irreversibly lost by antibiotic treatment and that their replacement could provide a health benefit. We suggest that D. melanogaster can be a useful model organism to study the activities of gut microbiota and their interaction with the immune system.}, }
@article {pmid21553265, year = {2011}, author = {Edmunds, PJ and Putnam, HM and Nisbet, RM and Muller, EB}, title = {Benchmarks in organism performance and their use in comparative analyses.}, journal = {Oecologia}, volume = {167}, number = {2}, pages = {379-390}, doi = {10.1007/s00442-011-2004-2}, pmid = {21553265}, issn = {1432-1939}, mesh = {Animals ; Anthozoa/*physiology ; Coral Reefs ; *Energy Metabolism ; Environment ; Models, Biological ; Species Specificity ; Stress, Physiological ; }, abstract = {Evaluating the response of organisms to stress assumes that functional benchmarks are available against which the response can be gauged, but this expectation remains unfulfilled for many taxa. As a result, attempts to describe the organismic effects of environmental degradation and physiological stress can prove misleading. Functional benchmarks and the effects of stress are particularly germane to coral reefs that globally are exposed to significant environmental challenges, and in this study, we compiled data on scleractinian corals to describe a reference against which stress responses can be gauged. Based on this construct, we tested the veracity of well-established contrasts--involving differences in physiological function among depths and families--to evaluate the capacity of available data to support synthetic analyses. Our analysis used 126 papers describing 37 genera, and at least 73 species, and described 13 traits, first independent of depth, and second, by depth. Data appropriate for these analyses were so sparse that depth- and family-level effects were inconspicuous, although the depth contrast revealed a decline in dark respiration and an increase in calcification (both normalized to area) in deeper water. Our analyses of scleractinian literature revealed limitations of the data available for synthetic analyses, as well for describing functional benchmarks within this taxon. We attribute some of these effects to differences in the physical environment under which measurements were made, and suspect that such problems are commonplace for other taxa. Dynamic Energy Budget (DEB) models provide one means to overcome some of these problems, and they can be used for any taxon to quantitatively summarize data for comparative analyses of stressor responses. The suitability of these models is illustrated for scleractinian corals by predicting from first principles the ratio of Symbiodinium to holobiont carbon and the respiration.}, }
@article {pmid21523464, year = {2011}, author = {Golberg, K and Eltzov, E and Shnit-Orland, M and Marks, RS and Kushmaro, A}, title = {Characterization of quorum sensing signals in coral-associated bacteria.}, journal = {Microbial ecology}, volume = {61}, number = {4}, pages = {783-792}, doi = {10.1007/s00248-011-9848-1}, pmid = {21523464}, issn = {1432-184X}, mesh = {4-Butyrolactone/analogs &amp; derivatives/metabolism ; Animals ; Anthozoa/*microbiology ; Bacteria/classification/genetics/*isolation &amp; purification/*metabolism ; Molecular Sequence Data ; Phylogeny ; *Quorum Sensing ; Signal Transduction ; }, abstract = {Marine environment habitats, such as the coral mucus layer, are abundant in nutrients and rich with diverse populations of microorganisms. Since interactions among microorganisms found in coral mucus can be either mutualistic or competitive, understanding quorum sensing-based acyl homoserine lactone (AHL) language may shed light on the interaction between coral-associated microbial communities in the native host. More than 100 bacterial isolates obtained from different coral species were screened for their ability to produce AHL. When screening the isolated coral bacteria for AHL induction activity using the reporter strains Escherichia coli K802NR-pSB1075 and Agrobacterium tumefaciens KYC55, we found that approximately 30% of the isolates tested positive. Thin layer chromatography separation of supernatant extracts revealed different AHL profiles, with detection of at least one active compound in the supernatant of those bacterial extracts being able to induce AHL activity in the two different bioreporter strains. The active extract of bacterial isolate 3AT 1-10-4 was subjected to further analysis by preparative thin layer chromatography and liquid chromatography tandem mass spectrometry. One of the compounds was found to correspond with N-(3-hydroxydecanoyl)-L-homoserine lactone. 16S rRNA gene sequencing of the isolates with positive AHL activity affiliated them with the Vibrio genus. Understanding the ecological role of AHL in the coral environment and its regulatory circuits in the coral holobiont-associated microbial community will further expand our knowledge of such interactions.}, }
@article {pmid21509042, year = {2011}, author = {Alagely, A and Krediet, CJ and Ritchie, KB and Teplitski, M}, title = {Signaling-mediated cross-talk modulates swarming and biofilm formation in a coral pathogen Serratia marcescens.}, journal = {The ISME journal}, volume = {5}, number = {10}, pages = {1609-1620}, doi = {10.1038/ismej.2011.45}, pmid = {21509042}, issn = {1751-7370}, mesh = {Acyl-Butyrolactones/metabolism ; Animals ; Anthozoa/*microbiology/physiology ; Bacterial Physiological Phenomena ; *Biofilms ; Ecology ; *Quorum Sensing ; Serratia marcescens/*metabolism ; Symbiosis ; }, abstract = {Interactions within microbial communities associated with marine holobionts contribute importantly to the health of these symbiotic organisms formed by invertebrates, dinoflagellates and bacteria. However, mechanisms that control invertebrate-associated microbiota are not yet fully understood. Hydrophobic compounds that were isolated from surfaces of asymptomatic corals inhibited biofilm formation by the white pox pathogen Serratia marcescens PDL100, indicating that signals capable of affecting the associated microbiota are produced in situ. However, neither the origin nor structures of these signals are currently known. A functional survey of bacteria recovered from coral mucus and from cultures of the dinoflagellate Symbiodinium spp. revealed that they could alter swarming and biofilm formation in S. marcescens. As swarming and biofilm formation are inversely regulated, the ability of some native α-proteobacteria to affect both behaviors suggests that the α-proteobacterial signal(s) target a global regulatory switch controlling the behaviors in the pathogen. Isolates of Marinobacter sp. inhibited both biofilm formation and swarming in S. marcescens PDL100, without affecting growth of the coral pathogen, indicative of the production of multiple inhibitors, likely targeting lower level regulatory genes or functions. A multi-species cocktail containing these strains inhibited progression of a disease caused by S. marcescens in a model polyp Aiptasia pallida. An α-proteobacterial isolate 44B9 had a similar effect. Even though ∼4% of native holobiont-associated bacteria produced compounds capable of triggering responses in well-characterized N-acyl homoserine lactone (AHL) biosensors, there was no strong correlation between the production of AHL-like signals and disruption of biofilms or swarming in S. marcescens.}, }
@article {pmid21468227, year = {2010}, author = {Jones, BV}, title = {The human gut mobile metagenome: a metazoan perspective.}, journal = {Gut microbes}, volume = {1}, number = {6}, pages = {415-431}, doi = {10.4161/gmic.1.6.14087}, pmid = {21468227}, issn = {1949-0984}, support = {//Medical Research Council/United Kingdom ; }, mesh = {Bacteria/*genetics ; Gastrointestinal Tract/*microbiology ; Humans ; *Metagenome ; Plasmids/*analysis ; }, abstract = {Using the culture independent TRACA system in conjunction with a comparative metagenomic approach, we have recently explored the pool of plasmids associated with the human gut mobile metagenome. This revealed that some plasmids or plasmid families are present in the gut microbiomes of geographically isolated human hosts with a broad global distribution (America, Japan and Europe), and are potentially unique to the human gut microbiome. Functions encoded by the most widely distributed plasmid (pTRACA22) were found to be enriched in the human gut microbiome when compared to microbial communities from other environments, and of particular interest was the increased prevalence of a putative RelBE toxin-antitoxin (TA) addiction module. Subsequent analysis revealed that this was most closely related to putative TA modules from gut associated bacteria belonging to the Firmicutes, but homologues of the RelE toxin were associated with all major bacterial divisions comprising the human gut microbiota. In this addendum, functions of the gut mobile metagenome are considered from the perspective of the human host, and within the context of the hologenome theory of human evolution. In doing so, our original analysis is also extended to include the gut metagenomes of a further 124 individuals comprising the METAHIT dataset. Differences in the incidence and relative abundance of pTRACA22 and associated TA modules between healthy individuals and those with inflammatory bowel diseases are explored, and potential functions of pTRACA22 type RelBE modules in the human gut microbiome are discussed.}, }
@article {pmid21425442, year = {2011}, author = {Rosenberg, E and Zilber-Rosenberg, I}, title = {Symbiosis and development: the hologenome concept.}, journal = {Birth defects research. Part C, Embryo today : reviews}, volume = {93}, number = {1}, pages = {56-66}, doi = {10.1002/bdrc.20196}, pmid = {21425442}, issn = {1542-9768}, mesh = {Adaptation, Biological ; Animals ; Anthozoa/genetics/*microbiology ; Biological Evolution ; Developmental Biology ; Epigenomics ; Genetic Variation ; Humans ; Insecta/genetics/*microbiology ; *Metagenome ; Mice ; Nitrogen Fixation ; Plants/genetics/*microbiology ; *Symbiosis ; }, abstract = {All animals and plants establish symbiotic relationships with microorganisms; often the combined genetic information of the diverse microbiota exceeds that of the host. How the genetic wealth of the microbiota affects all aspects of the holobiont's (host plus all of its associated microorganisms) fitness (adaptation, survival, development, growth and reproduction) and evolution is reviewed, using selected coral, insect, squid, plant, and human/mouse published experimental results. The data are discussed within the framework of the hologenome theory of evolution, which demonstrates that changes in environmental parameters, for example, diet, can cause rapid changes in the diverse microbiota, which not only can benefit the holobiont in the short term but also can be transmitted to offspring and lead to long lasting cooperations. As acquired characteristics (microbes) are heritable, consideration of the holobiont as a unit of selection in evolution leads to neo-Lamarckian principles within a Darwinian framework. The potential application of these principles can be seen in the growing fields of prebiotics and probiotics.}, }
@article {pmid21272183, year = {2011}, author = {Barott, KL and Rodriguez-Brito, B and Janouškovec, J and Marhaver, KL and Smith, JE and Keeling, P and Rohwer, FL}, title = {Microbial diversity associated with four functional groups of benthic reef algae and the reef-building coral Montastraea annularis.}, journal = {Environmental microbiology}, volume = {13}, number = {5}, pages = {1192-1204}, doi = {10.1111/j.1462-2920.2010.02419.x}, pmid = {21272183}, issn = {1462-2920}, mesh = {Animals ; Anthozoa/*microbiology ; *Biodiversity ; Carbon/metabolism ; Caribbean Region ; *Coral Reefs ; Cyanobacteria/classification/*genetics/growth &amp; development ; Gene Library ; Microalgae/*microbiology ; Phylogeny ; RNA, Bacterial/genetics ; RNA, Ribosomal, 16S/genetics ; Seawater/microbiology ; Sequence Analysis, DNA ; }, abstract = {The coral reef benthos is primarily colonized by corals and algae, which are often in direct competition with one another for space. Numerous studies have shown that coral-associated Bacteria are different from the surrounding seawater and are at least partially species specific (i.e. the same bacterial species on the same coral species). Here we extend these microbial studies to four of the major ecological functional groups of algae found on coral reefs: upright and encrusting calcifying algae, fleshy algae, and turf algae, and compare the results to the communities found on the reef-building coral Montastraea annularis. It was found using 16S rDNA tag pyrosequencing that the different algal genera harbour characteristic bacterial communities, and these communities were generally more diverse than those found on corals. While the majority of coral-associated Bacteria were related to known heterotrophs, primarily consuming carbon-rich coral mucus, algal-associated communities harboured a high percentage of autotrophs. The majority of algal-associated autotrophic Bacteria were Cyanobacteria and may be important for nitrogen cycling on the algae. There was also a rich diversity of photosynthetic eukaryotes associated with the algae, including protists, diatoms, and other groups of microalgae. Together, these observations support the hypothesis that coral reefs are a vast landscape of distinctive microbial communities and extend the holobiont concept to benthic algae.}, }
@article {pmid21209889, year = {2010}, author = {Turque, AS and Batista, D and Silveira, CB and Cardoso, AM and Vieira, RP and Moraes, FC and Clementino, MM and Albano, RM and Paranhos, R and Martins, OB and Muricy, G}, title = {Environmental shaping of sponge associated archaeal communities.}, journal = {PloS one}, volume = {5}, number = {12}, pages = {e15774}, doi = {10.1371/journal.pone.0015774}, pmid = {21209889}, issn = {1932-6203}, mesh = {Ammonia/chemistry ; Animals ; Archaea/*metabolism ; Biodiversity ; Brazil ; Ecology ; Environment ; Models, Genetic ; Molecular Sequence Data ; Phylogeny ; Plankton ; Porifera/*metabolism ; Principal Component Analysis ; RNA, Ribosomal, 16S/metabolism ; Seawater ; }, abstract = {BACKGROUND: Archaea are ubiquitous symbionts of marine sponges but their ecological roles and the influence of environmental factors on these associations are still poorly understood.<br><br>We compared the diversity and composition of archaea associated with seawater and with the sponges Hymeniacidon heliophila, Paraleucilla magna and Petromica citrina in two distinct environments: Guanabara Bay, a highly impacted estuary in Rio de Janeiro, Brazil, and the nearby Cagarras Archipelago. For this we used metagenomic analyses of 16S rRNA and ammonia monooxygenase (amoA) gene libraries. Hymeniacidon heliophila was more abundant inside the bay, while P. magna was more abundant outside and P. citrina was only recorded at the Cagarras Archipelago. Principal Component Analysis plots (PCA) generated using pairwise unweighted UniFrac distances showed that the archaeal community structure of inner bay seawater and sponges was different from that of coastal Cagarras Archipelago. Rarefaction analyses showed that inner bay archaeaoplankton were more diverse than those from the Cagarras Archipelago. Only members of Crenarchaeota were found in sponge libraries, while in seawater both Crenarchaeota and Euryarchaeota were observed. Although most amoA archaeal genes detected in this study seem to be novel, some clones were affiliated to known ammonia oxidizers such as Nitrosopumilus maritimus and Cenarchaeum symbiosum.<br><br>CONCLUSION/SIGNIFICANCE: The composition and diversity of archaeal communities associated with pollution-tolerant sponge species can change in a range of few kilometers, probably influenced by eutrophication. The presence of archaeal amoA genes in Porifera suggests that Archaea are involved in the nitrogen cycle within the sponge holobiont, possibly increasing its resistance to anthropogenic impacts. The higher diversity of Crenarchaeota in the polluted area suggests that some marine sponges are able to change the composition of their associated archaeal communities, thereby improving their fitness in impacted environments.}, }
@article {pmid21105980, year = {2011}, author = {Mumby, PJ and Elliott, IA and Eakin, CM and Skirving, W and Paris, CB and Edwards, HJ and Enríquez, S and Iglesias-Prieto, R and Cherubin, LM and Stevens, JR}, title = {Reserve design for uncertain responses of coral reefs to climate change.}, journal = {Ecology letters}, volume = {14}, number = {2}, pages = {132-140}, doi = {10.1111/j.1461-0248.2010.01562.x}, pmid = {21105980}, issn = {1461-0248}, mesh = {Acclimatization ; Algorithms ; Animals ; Anthozoa/growth &amp; development/*physiology ; Aquatic Organisms ; Bahamas ; Climate Change ; *Conservation of Natural Resources ; *Coral Reefs ; Hot Temperature ; Larva/growth &amp; development/physiology ; }, abstract = {Rising sea temperatures cause mass coral bleaching and threaten reefs worldwide. We show how maps of variations in thermal stress can be used to help manage reefs for climate change. We map proxies of chronic and acute thermal stress and develop evidence-based hypotheses for the future response of corals to each stress regime. We then incorporate spatially realistic predictions of larval connectivity among reefs of the Bahamas and apply novel reserve design algorithms to create reserve networks for a changing climate. We show that scales of larval dispersal are large enough to connect reefs from desirable thermal stress regimes into a reserve network. Critically, we find that reserve designs differ according to the anticipated scope for phenotypic and genetic adaptation in corals, which remains uncertain. Attempts to provide a complete reserve design that hedged against different evolutionary outcomes achieved limited success, which emphasises the importance of considering the scope for adaptation explicitly. Nonetheless, 15% of reserve locations were selected under all evolutionary scenarios, making them a high priority for early designation. Our approach allows new insights into coral holobiont adaptation to be integrated directly into an adaptive approach to management.}, }
@article {pmid21041648, year = {2010}, author = {Sharon, G and Segal, D and Ringo, JM and Hefetz, A and Zilber-Rosenberg, I and Rosenberg, E}, title = {Commensal bacteria play a role in mating preference of Drosophila melanogaster.}, journal = {Proceedings of the National Academy of Sciences of the United States of America}, volume = {107}, number = {46}, pages = {20051-20056}, doi = {10.1073/pnas.1009906107}, pmid = {21041648}, issn = {1091-6490}, mesh = {Animals ; Bacteria/*metabolism ; Diet/veterinary ; Drosophila melanogaster/growth &amp; development/*microbiology/*physiology ; Female ; Hydrocarbons/metabolism ; Integumentary System/microbiology ; Male ; Mating Preference, Animal/*physiology ; }, abstract = {Development of mating preference is considered to be an early event in speciation. In this study, mating preference was achieved by dividing a population of Drosophila melanogaster and rearing one part on a molasses medium and the other on a starch medium. When the isolated populations were mixed, &quot;molasses flies&quot; preferred to mate with other molasses flies and &quot;starch flies&quot; preferred to mate with other starch flies. The mating preference appeared after only one generation and was maintained for at least 37 generations. Antibiotic treatment abolished mating preference, suggesting that the fly microbiota was responsible for the phenomenon. This was confirmed by infection experiments with microbiota obtained from the fly media (before antibiotic treatment) as well as with a mixed culture of Lactobacillus species and a pure culture of Lactobacillus plantarum isolated from starch flies. Analytical data suggest that symbiotic bacteria can influence mating preference by changing the levels of cuticular hydrocarbon sex pheromones. The results are discussed within the framework of the hologenome theory of evolution.}, }
@article {pmid20962876, year = {2011}, author = {Chen, CP and Tseng, CH and Chen, CA and Tang, SL}, title = {The dynamics of microbial partnerships in the coral Isopora palifera.}, journal = {The ISME journal}, volume = {5}, number = {4}, pages = {728-740}, doi = {10.1038/ismej.2010.151}, pmid = {20962876}, issn = {1751-7370}, mesh = {Animals ; Anthozoa/*microbiology ; Bacteria/*classification/genetics/isolation &amp; purification ; Biodiversity ; Dinoflagellida/*classification/genetics/isolation &amp; purification ; Host Specificity ; Seasons ; Symbiosis ; }, abstract = {Both bacteria and algal symbionts (genus Symbiodinium), the two major microbial partners in the coral holobiont, respond to fluctuations in the environment, according to current reports; however, little evidence yet indicates that both populations have any direct interaction with each other in seasonal fluctuation. In this study, we present field observations of a compositional change in bacteria and Symbiodinium in the coral Isopora palifera in three separate coral colonies following monthly sampling from February to November in 2008. Using massively parallel pyrosequencing, over 200,000 bacterial V6 sequences were classified to build the bacterial community profile; in addition, the relative composition and quantity of Symbiodinium clades C and D were determined by real-time PCR. The results showed that coral-associated bacterial and Symbiodinium communities were highly dynamic and dissimilar among the tagged coral colonies, suggesting that the effect of host specificity was insignificant. The coral-associated bacterial community was more diverse (Shannon index up to 6.71) than previous estimates in other corals and showed rapid seasonal changes. The population ratios between clade C and D groups of Symbiodinium varied in the tagged coral colonies through the different seasons; clade D dominated in most of the samples. Although significant association between bacteria and symbiont was not detected, this study presents a more detailed picture of changes in these two major microbial associates of the coral at the same time, using the latest molecular approaches.}, }
@article {pmid23766221, year = {2010}, author = {Rosenberg, E and Sharon, G and Atad, I and Zilber-Rosenberg, I}, title = {The evolution of animals and plants via symbiosis with microorganisms.}, journal = {Environmental microbiology reports}, volume = {2}, number = {4}, pages = {500-506}, doi = {10.1111/j.1758-2229.2010.00177.x}, pmid = {23766221}, issn = {1758-2229}, abstract = {Animals and plants evolved from prokaryotes and have remained in close association with them. We suggest that early eukaryotic cells, formed by the fusion of two or more prokaryotes, already contained prokaryotic genetic information for aggregation and the formation of multicellular structures. The hologenome theory of evolution posits that a unit of selection in evolution is the holobiont (host plus symbionts). The hologenome is defined as the genetic information of the host and its microbiota, which function in consortium.