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08 Feb 2023 at 01:31
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Bibliography on: Holobiont


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RJR: Recommended Bibliography 08 Feb 2023 at 01:31 Created: 


Holobionts are assemblages of different species that form ecological units. Lynn Margulis proposed that any physical association between individuals of different species for significant portions of their life history is a symbiosis. All participants in the symbiosis are bionts, and therefore the resulting assemblage was first coined a holobiont by Lynn Margulis in 1991 in the book Symbiosis as a Source of Evolutionary Innovation. Holo is derived from the Ancient Greek word ὅλος (hólos) for “whole”. The entire assemblage of genomes in the holobiont is termed a hologenome.

Created with PubMed® Query: ( holobiont OR hologenome OR holospecies ) NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)


RevDate: 2023-02-07

Kazmi SA, EY Hsiao (2023)

Extending genetic risk for Alzheimer's disease from host to holobiont.

Cell pii:S0092-8674(23)00004-1 [Epub ahead of print].

The gut microbiota is implicated in risk for Alzheimer's disease (AD). A study in Science reports that depleting gut bacteria in mice with genetic risk for AD reduces neuropathology in a sex-dependent manner. This is reversed by administering short-chain fatty acids, suggesting that specific bacterial metabolites increase susceptibility to AD.

RevDate: 2023-02-07

Izraeli Y, Lepetit D, Atias S, et al (2022)

Genomic characterization of viruses associated with the parasitoid Anagyrus vladimiri (Hymenoptera: Encyrtidae).

The Journal of general virology, 103(12):.

Knowledge on symbiotic microorganisms of insects has increased dramatically in recent years, yet relatively little data are available regarding non-pathogenic viruses. Here we studied the virome of the parasitoid wasp Anagyrus vladimiri Triapitsyn (Hymenoptera: Encyrtidae), a biocontrol agent of mealybugs. By high-throughput sequencing of viral nucleic acids, we revealed three novel viruses, belonging to the families Reoviridae [provisionally termed AnvRV (Anagyrus vladimiri reovirus)], Iflaviridae (AnvIFV) and Dicistroviridae (AnvDV). Phylogenetic analysis further classified AnvRV in the genus Idnoreovirus, and AnvDV in the genus Triatovirus. The genome of AnvRV comprises 10 distinct genomic segments ranging in length from 1.5 to 4.2 kb, but only two out of the 10 ORFs have a known function. AnvIFV and AnvDV each have one polypeptide ORF, which is typical of iflaviruses but very un-common among dicistroviruses. Five conserved domains were found along both the ORFs of those two viruses. AnvRV was found to be fixed in an A. vladimiri population that was obtained from a mass rearing facility, whereas its prevalence in field-collected A. vladimiri was ~15 %. Similarly, the prevalence of AnvIFV and AnvDV was much higher in the mass rearing population than in the field population. The presence of AnvDV was positively correlated with the presence of Wolbachia in the same individuals. Transmission electron micrographs of females' ovaries revealed clusters and viroplasms of reovirus-like particles in follicle cells, suggesting that AnvRV is vertically transmitted from mother to offspring. AnvRV was not detected in the mealybugs, supporting the assumption that this virus is truly associated with the wasps. The possible effects of these viruses on A. vladimiri's biology, and on biocontrol agents in general, are discussed. Our findings identify RNA viruses as potentially involved in the multitrophic system of mealybugs, their parasitoids and other members of the holobiont.

RevDate: 2023-02-06

Germain RR, Feng S, Buffan L, et al (2023)

Changes in the functional diversity of modern bird species over the last million years.

Proceedings of the National Academy of Sciences of the United States of America, 120(7):e2201945119.

Despite evidence of declining biosphere integrity, we currently lack understanding of how the functional diversity associated with changes in abundance among ecological communities has varied over time and before widespread human disturbances. We combine morphological, ecological, and life-history trait data for >260 extant bird species with genomic-based estimates of changing effective population size (Ne) to quantify demographic-based shifts in avian functional diversity over the past million years and under pre-anthropogenic climate warming. We show that functional diversity was relatively stable over this period, but underwent significant changes in some key areas of trait space due to changing species abundances. Our results suggest that patterns of population decline over the Pleistocene have been concentrated in particular regions of trait space associated with extreme reproductive strategies and low dispersal ability, consistent with an overall erosion of functional diversity. Further, species most sensitive to climate warming occupied a relatively narrow region of functional space, indicating that the largest potential population increases and decreases under climate change will occur among species with relatively similar trait sets. Overall, our results identify fluctuations in functional space of extant species over evolutionary timescales and represent the demographic-based vulnerability of different regions of functional space among these taxa. The integration of paleodemographic dynamics with functional trait data enhances our ability to quantify losses of biosphere integrity before anthropogenic disturbances and attribute contemporary biodiversity loss to different drivers over time.

RevDate: 2023-02-03

Fujiyoshi S, Yarimizu K, Perera I, et al (2023)

Learning from mistakes: challenges in finding holobiont factors from environmental samples and the importance of methodological consistency.

Current opinion in biotechnology, 80:102897 pii:S0958-1669(23)00007-1 [Epub ahead of print].

The cause of harmful algal blooms has been a mystery, but research to elucidate its mechanism has progressed over the years thanks to genetic technologies. We have monitored toxic algae and its associated bacteria as a community, the so-called 'holobiont' in Chilean coastal waters for years from the perspective of bacteria as an algal bloom driver. This review describes the challenges of holobiont monitoring, specifically with respect to standardizing and compliance with the monitoring protocols to collect reliable and sustainable data. Further, we suggest adopting the high-throughput sequencing (HTS) standard operating procedure (SOP) by the International Human Microbiome to improve the quality and consistency of holobiont monitoring in the harmful algal world.

RevDate: 2023-02-02

Zhu W, Wang H, Li X, et al (2023)

Consistent responses of coral microbiome to acute and chronic heat stress exposures.

Marine environmental research, 185:105900 pii:S0141-1136(23)00028-4 [Epub ahead of print].

Frequent and intense heat waves lead to bleaching and even death of reef-building corals, and the thermal tolerance ultimately depends on the genetic composition of the holobiont. Here, we compared the effects of acute and chronic heat stress exposures on coral Porites cylindrica holobiont. Regardless of the temperature treatment, corals at 33 °C showed signs of bleaching and a significant decrease in photochemical efficiency (Fv/Fm). However, Symbiodiniaceae communities were relatively stable and all dominated by the same genus Cladocopium (C15). The relative abundanbce of core microbiome varied significantly, and they may provide several functions important to holobiont fitness. Both heat stress exposures induced the significant structural reorganization of coral-associated bacteria, with bacterial diversity and community heterogeneity significantly increasing with the temperature treatment. The modified stochasticity ratio (MST) revealed that stochastic processes dominated bacterial community assembly in thermally stressed corals. Certain core bacterial members that were hypothesized to fulfil functional niche decreased significantly, with the enrichment of potentially pathogenic and opportunistic bacteria in heat stress exposures. Thermally stressed corals had more positive correlation, higher network complexity and tighter associations among microbial taxa, relative to healthy corals. Overall, the coral microbiome exhibits similar responses to acute and chronic heat stress, and our study provides new insights about the deleterious impacts of complex warming oceans on coral holobiont.

RevDate: 2023-01-31

Lin Z, Zheng X, J Chen (2023)

Deciphering pH-dependent microbial taxa and functional gene co-occurrence in the coral Galaxea fascicularis.

Microbial ecology pii:10.1007/s00248-023-02183-0 [Epub ahead of print].

How the coral microbiome responds to oceanic pH changes due to anthropogenic climate change, including ocean acidification and deliberate artificial alkalization, remains an open question. Here, we applied a 16S profile and GeoChip approach to microbial taxonomic and gene functional landscapes in the coral Galaxea fascicularis under three pH levels (7.85, 8.15, and 8.45) and tested the influence of pH changes on the cell growth of several coral-associated strains and bacterial populations. Statistical analysis of GeoChip-based data suggested that both ocean acidification and alkalization destabilized functional cores related to aromatic degradation, carbon degradation, carbon fixation, stress response, and antibiotic biosynthesis in the microbiome, which are related to holobiont carbon cycling and health. The taxonomic analysis revealed that bacterial species richness was not significantly different among the three pH treatments, but the community compositions were significantly distinct. Acute seawater alkalization leads to an increase in pathogens as well as a stronger taxonomic shift than acidification, which is worth considering when using artificial ocean alkalization to protect coral ecosystems from ocean acidification. In addition, our co-occurrence network analysis reflected microbial community and functional shifts in response to pH change cues, which will further help to understand the functional ecological role of the microbiome in coral resilience.

RevDate: 2023-01-31

Bonthond G, Neu AK, Bayer T, et al (2023)

Non-native hosts of an invasive seaweed holobiont have more stable microbial communities compared to native hosts in response to thermal stress.

Ecology and evolution, 13(1):e9753.

Seaweeds are colonized by a microbial community, which can be directly linked to their performance. This community is shaped by an interplay of stochastic and deterministic processes, including mechanisms which the holobiont host deploys to manipulate its associated microbiota. The Anna Karenina principle predicts that when a holobiont is exposed to suboptimal or stressful conditions, these host mechanisms may be compromised. This leads to a relative increase of stochastic processes that may potentially result in the succession of a microbial community harmful to the host. Based on this principle, we used the variability in microbial communities (i.e., beta diversity) as a proxy for stability within the invasive holobiont Gracilaria vermiculophylla during a simulated invasion in a common garden experiment. Independent of host range, host performance declined at elevated temperature (22°C) and disease incidence and beta diversity increased. Under thermally stressful conditions, beta diversity increased more in epibiota from native populations, suggesting that epibiota from non-native holobionts are thermally more stable. This pattern reflects an increase in deterministic processes acting on epibiota associated with non-native hosts, which in the setting of a common garden can be assumed to originate from the host itself. Therefore, these experimental data suggest that the invasion process may have selected for hosts better able to maintain stable microbiota during stress. Future studies are needed to identify the underlying host mechanisms.

RevDate: 2023-01-26

Li JH, Muhammad Aslam M, Gao YY, et al (2023)

Microbiome-mediated signal transduction within the plant holobiont.

Trends in microbiology pii:S0966-842X(22)00340-7 [Epub ahead of print].

Microorganisms colonizing the plant rhizosphere and phyllosphere play crucial roles in plant growth and health. Recent studies provide new insights into long-distance communication from plant roots to shoots in association with their commensal microbiome. In brief, these recent advances suggest that specific plant-associated microbial taxa can contribute to systemic plant responses associated with the enhancement of plant health and performance in face of a variety of biotic and abiotic stresses. However, most of the mechanisms associated with microbiome-mediated signal transduction in plants remain poorly understood. In this review, we provide an overview of long-distance signaling mechanisms within plants mediated by the commensal plant-associated microbiomes. We advocate the view of plants and microbes as a holobiont and explore key molecules and mechanisms associated with plant-microbe interactions and changes in plant physiology activated by signal transduction.

RevDate: 2023-01-26

Bolt Botnen A, Bjørnsen MB, Alberdi A, et al (2023)

A simplified protocol for DNA extraction from FTA cards for faecal microbiome studies.

Heliyon, 9(1):e12861.

As metagenomic studies continue to increase in size and complexity, they are often required to incorporate data from geographically isolated locations or longitudinal time samples. This represents a technical challenge, given that many of the commonly used methods used for sample collection, storage, and DNA extraction are sensitive to differences related to the time, storage and chemistry involved. FTA cards have been previously proposed as a simple, reliable and cost-efficient method for the preservation of animal faecal microbiomes. In this study, we report a simplified extraction methodology for recovering microbiome DNA from faeces stored on FTA cards and compare its performance to a common alternative means of characterising such microbiomes; namely, immediate freezing of the faeces followed by DNA extraction using the Qiagen PowerSoil DNA isolation kit. Our results show that overall the application of our simplified DNA extraction methodology yields microbial community results that have higher diversity and an expanded core microbiome than that found using the PowerSoil methodology. This suggests that the FTA card extraction method presented here is a viable alternative for metagenomic studies using faecal material when traditional freeze-based storage methods are not feasible.

RevDate: 2023-01-23

Rosado PM, Cardoso PM, Rosado JG, et al (2023)

Exploring the Potential Molecular Mechanisms of Interactions between a Probiotic Consortium and Its Coral Host.

mSystems [Epub ahead of print].

Beneficial microorganisms for corals (BMCs) have been demonstrated to be effective probiotics to alleviate bleaching and mitigate coral mortality in vivo. The selection of putative BMCs is traditionally performed manually, using an array of biochemical and molecular tests for putative BMC traits. We present a comprehensive genetic survey of BMC traits using a genome-based framework for the identification of alternative mechanisms that can be used for future in silico selection of BMC strains. We identify exclusive BMC traits associated with specific strains and propose new BMC mechanisms, such as the synthesis of glycine betaine and ectoines. Our roadmap facilitates the selection of BMC strains while increasing the array of genetic targets that can be included in the selection of putative BMC strains to be tested as coral probiotics. IMPORTANCE Probiotics are currently the main hope as a potential medicine for corals, organisms that are considered the marine "canaries of the coal mine" and that are threatened with extinction. Our experiments have proved the concept that probiotics mitigate coral bleaching and can also prevent coral mortality. Here, we present a comprehensive genetic survey of probiotic traits using a genome-based framework. The main outcomes are a roadmap that facilitates the selection of coral probiotic strains while increasing the array of mechanisms that can be included in the selection of coral probiotics.

RevDate: 2023-01-23

Burgunter-Delamare B, Rousvoal S, Legeay E, et al (2022)

The Saccharina latissima microbiome: Effects of region, season, and physiology.

Frontiers in microbiology, 13:1050939.

INTRODUCTION: Saccharina latissima is a canopy-forming species of brown algae and, as such, is considered an ecosystem engineer. Several populations of this alga are exploited worldwide, and a decrease in the abundance of S. latissima at its southern distributional range limits has been observed. Despite its economic and ecological interest, only a few data are available on the composition of microbiota associated with S. latissima and its role in algal physiologyn.

METHODS: We studied the whole bacterial community composition associated with S. latissima samples from three locations (Brittany, Helgoland, and Skagerrak) by 16S metabarcoding analyses at different scales: algal blade part, regions, season (at one site), and algal physiologic state.

RESULTS AND DISCUSSION: We have shown that the difference in bacterial composition is driven by factors of decreasing importance: (i) the algal tissues (apex/meristem), (ii) the geographical area, (iii) the seasons (at the Roscoff site), and (iv) the algal host's condition (healthy vs. symptoms). Overall, Alphaproteobacteria, Gammaproteobacteria, and Bacteroidia dominated the general bacterial communities. Almost all individuals hosted bacteria of the genus Granulosicoccus, accounting for 12% of the total sequences, and eight additional core genera were identified. Our results also highlight a microbial signature characteristic for algae in poor health independent of the disease symptoms. Thus, our study provides a comprehensive overview of the S. latissima microbiome, forming a basis for understanding holobiont functioning.

RevDate: 2023-01-23

Tandon K, Ricci F, Costa J, et al (2022)

Genomic view of the diversity and functional role of archaea and bacteria in the skeleton of the reef-building corals Porites lutea and Isopora palifera.

GigaScience, 12:.

At present, our knowledge on the compartmentalization of coral holobiont microbiomes is highly skewed toward the millimeter-thin coral tissue, leaving the diverse coral skeleton microbiome underexplored. Here, we present a genome-centric view of the skeleton of the reef-building corals Porites lutea and Isopora palifera, through a compendium of ∼400 high-quality bacterial and archaeal metagenome-assembled genomes (MAGs), spanning 34 phyla and 57 classes. Skeletal microbiomes harbored a diverse array of stress response genes, including dimethylsulfoniopropionate synthesis (dsyB) and metabolism (DMSP lyase). Furthermore, skeletal MAGs encoded an average of 22 ± 15 genes in P. lutea and 28 ± 23 in I. palifera with eukaryotic-like motifs thought to be involved in maintaining host association. We provide comprehensive insights into the putative functional role of the skeletal microbiome on key metabolic processes such as nitrogen fixation, dissimilatory and assimilatory nitrate, and sulfate reduction. Our study provides critical genomic resources for a better understanding of the coral skeletal microbiome and its role in holobiont functioning.

RevDate: 2023-01-21

Hansen CCR, Láruson ÁJ, Rasmussen JA, et al (2023)

Genomic diversity and differentiation between island and mainland populations of White-tailed Eagles (Haliaeetus albicilla).

Molecular ecology [Epub ahead of print].

Divergence in the face of high dispersal capabilities is a documented but poorly understood phenomenon. The white-tailed eagle (Haliaeetus albicilla) has a large geographic dispersal capability and should theoretically be able to maintain genetic homogeneity across its dispersal range. However, following analysis of the genomic variation of white-tailed eagles, from both historical and contemporary samples, clear signatures of ancient biogeographic substructure across Europe and the North-East Atlantic is observed. The greatest genomic differentiation was observed between island (Greenland and Iceland) and mainland (Denmark, Norway and Estonia) populations. The two island populations share a common ancestry from a single mainland population, distinct from the other sampled mainland populations, and despite the potential for high connectivity between Iceland and Greenland they are well separated from each other and are characterized by inbreeding and little variation. Temporal differences also highlight a pattern of regional populations persisting despite the potential for admixture. All sampled populations generally showed a decline in effective population size over time, which may have been shaped by four historical events: I) isolation of refugia during the last glacial period 110-115,000 years ago, II) population divergence following the colonization of the deglaciated areas ~10,000 years ago, III) human population expansion, which led to the settlement in Iceland ~1,100 years ago, and IV) human persecution and exposure to toxic pollutants during the last two centuries.

RevDate: 2023-01-21

Conte C, Apostolaki ET, Vizzini S, et al (2023)

A Tight Interaction between the Native Seagrass Cymodocea nodosa and the Exotic Halophila stipulacea in the Aegean Sea Highlights Seagrass Holobiont Variations.

Plants (Basel, Switzerland), 12(2): pii:plants12020350.

Seagrasses harbour bacterial communities with which they constitute a functional unit called holobiont that responds as a whole to environmental changes. Epiphytic bacterial communities rapidly respond to both biotic and abiotic factors, potentially contributing to the host fitness. The Lessepsian migrant Halophila stipulacea has a high phenotypical plasticity and harbours a highly diverse epiphytic bacterial community, which could support its invasiveness in the Mediterranean Sea. The current study aimed to evaluate the Halophila/Cymodocea competition in the Aegean Sea by analysing each of the two seagrasses in a meadow zone where these intermingled, as well as in their monospecific zones, at two depths. Differences in holobionts were evaluated using seagrass descriptors (morphometric, biochemical, elemental, and isotopic composition) to assess host changes, and 16S rRNA gene to identify bacterial community structure and composition. An Indicator Species Index was used to identify bacteria significantly associated with each host. In mixed meadows, native C. nodosa was shown to be affected by the presence of exotic H. stipulacea, in terms of both plant descriptors and bacterial communities, while H. stipulacea responded only to environmental factors rather than C. nodosa proximity. This study provided evidence of the competitive advantage of H. stipulacea on C. nodosa in the Aegean Sea and suggests the possible use of associated bacterial communities as an ecological seagrass descriptor.

RevDate: 2023-01-21

Mathew SA, Helander M, Saikkonen K, et al (2023)

Epichloë Endophytes Shape the Foliar Endophytic Fungal Microbiome and Alter the Auxin and Salicylic Acid Phytohormone Levels in Two Meadow Fescue Cultivars.

Journal of fungi (Basel, Switzerland), 9(1): pii:jof9010090.

Plants harbor a large diversity of endophytic microbes. Meadow fescue (Festuca pratensis) is a cool-season grass known for its symbiotic relationship with the systemic and vertically-via seeds-transmitted fungal endophyte Epichloë uncinata, yet its effects on plant hormones and the microbial community is largely unexplored. Here, we sequenced the endophytic bacterial and fungal communities in the leaves and roots, analyzing phytohormone concentrations and plant performance parameters in Epichloë-symbiotic (E+) and Epichloë-free (E-) individuals of two meadow fescue cultivars. The endophytic microbial community differed between leaf and root tissues independent of Epichloë symbiosis, while the fungal community was different in the leaves of Epichloë-symbiotic and Epichloë-free plants in both cultivars. At the same time, Epichloë symbiosis decreased salicylic acid and increased auxin concentrations in leaves. Epichloë-symbiotic plants showed higher biomass and higher seed mass at the end of the season. Our results demonstrate that Epichloë symbiosis alters the leaf fungal microbiota, which coincides with changes in phytohormone concentrations, indicating that Epichloë endophytes affect both plant immune responses and other fungal endophytes. Whether the effect of Epichloë endophytes on other fungal endophytes is connected to changes in phytohormone concentrations remains to be elucidated.

RevDate: 2023-01-20

Deutsch JM, Green MO, Akavaram P, et al (2023)

Limited Metabolomic Overlap between Commensal Bacteria and Marine Sponge Holobionts Revealed by Large Scale Culturing and Mass Spectrometry-Based Metabolomics: An Undergraduate Laboratory Pedagogical Effort at Georgia Tech.

Marine drugs, 21(1): pii:md21010053.

Sponges are the richest source of bioactive organic small molecules, referred to as natural products, in the marine environment. It is well established that laboratory culturing-resistant symbiotic bacteria residing within the eukaryotic sponge host matrix often synthesize the natural products that are detected in the sponge tissue extracts. However, the contributions of the culturing-amenable commensal bacteria that are also associated with the sponge host to the overall metabolome of the sponge holobiont are not well defined. In this study, we cultured a large library of bacteria from three marine sponges commonly found in the Florida Keys. Metabolomes of isolated bacterial strains and that of the sponge holobiont were compared using mass spectrometry to reveal minimal metabolomic overlap between commensal bacteria and the sponge hosts. We also find that the phylogenetic overlap between cultured commensal bacteria and that of the sponge microbiome is minimal. Despite these observations, the commensal bacteria were found to be a rich resource for novel natural product discovery. Mass spectrometry-based metabolomics provided structural insights into these cryptic natural products. Pedagogic innovation in the form of laboratory curricula development is described which provided undergraduate students with hands-on instruction in microbiology and natural product discovery using metabolomic data mining strategies.

RevDate: 2023-01-20
CmpDate: 2023-01-20

Mayfield AB (2023)

Multi-macromolecular Extraction from Endosymbiotic Anthozoans.

Methods in molecular biology (Clifton, N.J.), 2625:17-56.

Obligately symbiotic associations between reef-building corals (anthozoan cnidarians) and photosynthetically active dinoflagellates of the family Symbiodiniaceae comprise the functional basis of all coral reef ecosystems. Given the existential threats of global climate change toward these thermo-sensitive entities, there is an urgent need to better understand the physiological implications of changes in the abiotic milieu of scleractinian corals and their mutualistic algal endosymbionts. Although initially slow to leverage the immense breakthroughs in molecular biotechnology that have benefited humankind, coral biologists are making up for lost time in exploiting an array of ever-advancing molecular tools for answering key questions pertaining to the survival of corals in an ever-changing world. In order to comprehensively characterize the multi-omic landscape of the coral holobiont-the cnidarian host, its intracellular dinoflagellates, and a plethora of other microbial constituents-I introduce a series of protocols herein that yield large quantities of high-quality RNA, DNA, protein, lipids, and polar metabolites from a diverse array of reef corals and endosymbiotic sea anemones. Although numerous published articles in the invertebrate zoology field feature protocols that lead to sufficiently high yield of intact host coral macromolecules, through using the approach outlined herein one may simultaneously acquire a rich, multi-compartmental biochemical pool that truly reflects the complex and dynamic nature of these animal-plant chimeras.

RevDate: 2023-01-18

Takagi T, Aoyama K, Motone K, et al (2023)

Mutualistic Interactions between Dinoflagellates and Pigmented Bacteria Mitigate Environmental Stress.

Microbiology spectrum [Epub ahead of print].

Scleractinian corals form symbiotic relationships with a variety of microorganisms, including endosymbiotic dinoflagellates of the family Symbiodiniaceae, and with bacteria, which are collectively termed coral holobionts. Interactions between hosts and their symbionts are critical to the physiological status of corals. Coral-microorganism interactions have been studied extensively, but dinoflagellate-bacterial interactions remain largely unexplored. Here, we developed a microbiome manipulation method employing KAS-antibiotic treatment (kanamycin, ampicillin, and streptomycin) to favor pigmented bacteria residing on cultured Cladocopium and Durusdinium, major endosymbionts of corals, and isolated several carotenoid-producing bacteria from cell surfaces of the microalgae. Following KAS-antibiotic treatment of Cladocopium sp. strain NIES-4077, pigmented bacteria increased 8-fold based on colony-forming assays from the parental strain, and 100% of bacterial sequences retrieved through 16S rRNA amplicon sequencing were affiliated with the genus Maribacter. Microbiome manipulation enabled host microalgae to maintain higher maximum quantum yield of photosystem II (variable fluorescence divided by maximum fluorescence [Fv/Fm]) under light-stress conditions, compared to the parental strain. Furthermore, by combining culture-dependent and -independent techniques, we demonstrated that species of the family Symbiodiniaceae and pigmented bacteria form strong interactions. Dinoflagellates protected bacteria from antibiotics, while pigmented bacteria protected microalgal cells from light stress via carotenoid production. Here, we describe for the first time a symbiotic relationship in which dinoflagellates and bacteria mutually reduce environmental stress. Investigations of microalgal-bacterial interactions further document bacterial contributions to coral holobionts and may facilitate development of novel techniques for microbiome-mediated coral reef conservation. IMPORTANCE Coral reefs cover less than 0.1% of the ocean floor, but about 25% of all marine species depend on coral reefs at some point in their life cycles. However, rising ocean temperatures associated with global climate change are a serious threat to coral reefs, causing dysfunction of the photosynthetic apparatus of endosymbiotic microalgae of corals, and overproducing reactive oxygen species harmful to corals. We manipulated the microbiome using an antibiotic treatment to favor pigmented bacteria, enabling their symbiotic microalgal partners to maintain higher photosynthetic function under insolation stress. Furthermore, we investigated mechanisms underlying microalgal-bacterial interactions, describing for the first time a symbiotic relationship in which the two symbionts mutually reduce environmental stress. Our findings extend current insights about microalgal-bacterial interactions, enabling better understanding of bacterial contributions to coral holobionts under stressful conditions and offering hope of reducing the adverse impacts of global warming on coral reefs.

RevDate: 2023-01-18

Pirolo M, Espinosa-Gongora C, Alberdi A, et al (2023)

Bacterial topography of the upper and lower respiratory tract in pigs.

Animal microbiome, 5(1):5.

BACKGROUND: Understanding the complex structures and interactions of the bacterial communities inhabiting the upper (URT) and lower (LRT) respiratory tract of pigs is at an early stage. The objective of this study was to characterize the bacterial topography of three URT (nostrils, choana, and tonsils) and LRT (proximal trachea, left caudal lobe and secondary bronchi) sites in pigs. Thirty-six post-mortem samples from six pigs were analysed by 16S rRNA gene quantification and sequencing, and the microbiota in nostrils and trachea was additionally profiled by shotgun sequencing.

RESULTS: The bacterial composition obtained by the two methods was congruent, although metagenomics recovered only a fraction of the diversity (32 metagenome-assembled genomes) due to the high proportion (85-98%) of host DNA. The highest abundance of 16S rRNA copies was observed in nostrils, followed by tonsils, trachea, bronchi, choana and lung. Bacterial richness and diversity were lower in the LRT compared to the URT. Overall, Firmicutes and Proteobacteria were identified as predominant taxa in all sample types. Glasserella (15.7%), Streptococcus (14.6%) and Clostridium (10.1%) were the most abundant genera but differences in microbiota composition were observed between the two tracts as well as between sampling sites within the same tract. Clear-cut differences were observed between nasal and tonsillar microbiomes (R-values 0.85-0.93), whereas bacterial communities inhabiting trachea and lung were similar (R-values 0.10-0.17). Moraxella and Streptococcus were more common in bronchial mucosal scraping than in lavage, probably because of mucosal adherence. The bacterial microbiota of the choana was less diverse than that of the nostrils and similar to the tracheal microbiota (R-value 0.24), suggesting that the posterior nasal cavity serves as the primary source of bacteria for the LRT.

CONCLUSION: We provide new knowledge on microbiota composition and species abundance in distinct ecological niches of the pig respiratory tract. Our results shed light on the distribution of opportunistic bacterial pathogens across the respiratory tract and support the hypothesis that bacteria present in the lungs originate from the posterior nasal cavity. Due to the high abundance of host DNA, high-resolution profiling of the pig respiratory microbiota by shotgun sequencing requires methods for host DNA depletion.

RevDate: 2023-01-13

Feldner-Busztin D, Firbas Nisantzis P, Jane Edmunds S, et al (2023)

Dealing with dimensionality: the application of machine learning to multi-omics data.

Bioinformatics (Oxford, England) pii:6986971 [Epub ahead of print].

MOTIVATION: Machine learning (ML) methods are motivated by the need to automate information extraction from large data sets in order to support human users in data-driven tasks. This is an attractive approach for integrative joint analysis of vast amounts of omics data produced in next generation sequencing and other -omics assays. A systematic assessment of the current literature can help to identify key trends and potential gaps in methodology and applications. We surveyed the literature on ML multi-omic data integration and quantitatively explored the goals, techniques and data involved in this field. We were particularly interested in examining how researchers use ML to deal with the volume and complexity of these datasets.

RESULTS: Our main finding is that the methods used are those that address the challenges of datasets with few samples and many features. Dimensionality reduction methods are used to reduce the feature count alongside models that can also appropriately handle relatively few samples. Popular techniques include autoencoders, random forests and support vector machines. We also found that the field is heavily influenced by the use of The Cancer Genome Atlas data set, which is accessible and contains many diverse experiments.

AVAILABILITY: All data and processing scripts are available at this GitLab repository: https://gitlab.com/polavieja_lab/ml_multi-omics_review/ or in Zenodo: https://doi.org/10.5281/zenodo.7361807.

SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

RevDate: 2023-01-11

Šigutová H, Šigut M, Pyszko P, et al (2023)

Seasonal Shifts in Bacterial and Fungal Microbiomes of Leaves and Associated Leaf-Mining Larvae Reveal Persistence of Core Taxa Regardless of Diet.

Microbiology spectrum [Epub ahead of print].

Microorganisms are key mediators of interactions between insect herbivores and their host plants. Despite a substantial interest in studying various aspects of these interactions, temporal variations in microbiomes of woody plants and their consumers remain understudied. In this study, we investigated shifts in the microbiomes of leaf-mining larvae (Insecta: Lepidoptera) and their host trees over one growing season in a deciduous temperate forest. We used 16S and ITS2 rRNA gene metabarcoding to profile the bacterial and fungal microbiomes of leaves and larvae. We found pronounced shifts in the leaf and larval microbiota composition and richness as the season progressed, and bacteria and fungi showed consistent patterns. The quantitative similarity between leaf and larval microbiota was very low for bacteria (~9%) and decreased throughout the season, whereas fungal similarity increased and was relatively high (~27%). In both leaves and larvae, seasonality, along with host taxonomy, was the most important factor shaping microbial communities. We identified frequently occurring microbial taxa with significant seasonal trends, including those more prevalent in larvae (Streptococcus, Candida sake, Debaryomyces prosopidis, and Neoascochyta europaea), more prevalent in leaves (Erwinia, Seimatosporium quercinum, Curvibasidium cygneicollum, Curtobacterium, Ceramothyrium carniolicum, and Mycosphaerelloides madeirae), and frequent in both leaves and larvae (bacterial strain P3OB-42, Methylobacterium/Methylorubrum, Bacillus, Acinetobacter, Cutibacterium, and Botrytis cinerea). Our results highlight the importance of considering seasonality when studying the interactions between plants, herbivorous insects, and their respective microbiomes, and illustrate a range of microbial taxa persistent in larvae, regardless of their occurrence in the diet. IMPORTANCE Leaf miners are endophagous insect herbivores that feed on plant tissues and develop and live enclosed between the epidermis layers of a single leaf for their entire life cycle. Such close association is a precondition for the evolution of more intimate host-microbe relationships than those found in free-feeding herbivores. Simultaneous comparison of bacterial and fungal microbiomes of leaves and their tightly linked consumers over time represents an interesting study system that could fundamentally contribute to the ongoing debate on the microbial residence of insect gut. Furthermore, leaf miners are ideal model organisms for interpreting the ecological and evolutionary roles of microbiota in host plant specialization. In this study, the larvae harbored specific microbial communities consisting of core microbiome members. Observed patterns suggest that microbes, especially bacteria, may play more important roles in the caterpillar holobiont than generally presumed.

RevDate: 2023-01-11

Chou PH, Hu MY, Guh YJ, et al (2023)

Cellular mechanisms underlying extraordinary sulfide tolerance in a crustacean holobiont from hydrothermal vents.

Proceedings. Biological sciences, 290(1990):20221973.

The shallow-water hydrothermal vent system of Kueishan Island has been described as one of the world's most acidic and sulfide-rich marine habitats. The only recorded metazoan species living in the direct vicinity of the vents is Xenograpsus testudinatus, a brachyuran crab endemic to marine sulfide-rich vent systems. Despite the toxicity of hydrogen sulfide, X. testudinatus occupies an ecological niche in a sulfide-rich habitat, with the underlying detoxification mechanism remaining unknown. Using laboratory and field-based experiments, we characterized the gills of X. testudinatus that are the major site of sulfide detoxification. Here sulfide is oxidized to thiosulfate or bound to hypotaurine to generate the less toxic thiotaurine. Biochemical and molecular analyses demonstrated that the accumulation of thiosulfate and hypotaurine is mediated by the sodium-independent sulfate anion transporter (SLC26A11) and taurine transporter (Taut), which are expressed in gill epithelia. Histological and metagenomic analyses of gill tissues demonstrated a distinct bacterial signature dominated by Epsilonproteobacteria. Our results suggest that thiotaurine synthesized in gills is used by sulfide-oxidizing endo-symbiotic bacteria, creating an effective sulfide-buffering system. This work identified physiological mechanisms involving host-microbe interactions that support life of a metazoan in one of the most extreme environments on our planet.

RevDate: 2023-01-11

Singh T, Sakai K, Ishida-Castañeda J, et al (2023)

Short-term improvement of heat tolerance in naturally growing Acropora corals in Okinawa.

PeerJ, 11:e14629.

Mass bleaching and subsequent mortality of reef corals by heat stress has increased globally since the late 20th century, due to global warming. Some experimental studies have reported that corals may increase heat tolerance for short periods, but only a few such studies have monitored naturally-growing colonies. Therefore, we monitored the survival, growth, and bleaching status of Acropora corals in fixed plots by distinguishing individual colonies on a heat-sensitive reef flat in Okinawa, Japan. The level of heat stress, assessed by the modified version of degree heating week duration in July and August, when the seawater temperature was the highest, was minimally but significantly higher in 2017 than in 2016; however, the same colonies exhibited less bleaching and mortality in 2017 than in 2016. Another study conducted at the same site showed that the dominant unicellular endosymbiotic algal species did not change before and after the 2016 bleaching, indicating that shifting and switching of the Symbiodiniaceae community did not contribute to improved heat tolerance. Colonies that suffered from partial mortality in 2016 were completely bleached at higher rates in 2017 than those without partial mortality in 2016. The present results suggest that either genetic or epigenetic changes in coral hosts and/or algal symbionts, or the shifting or switching of microbes other than endosymbionts, may have improved coral holobiont heat tolerance.

RevDate: 2023-01-09

Jiang M, Li S, Li H, et al (2023)

Reprogramming of microbial community in barley root endosphere and rhizosphere soil by polystyrene plastics with different particle sizes.

The Science of the total environment pii:S0048-9697(23)00035-9 [Epub ahead of print].

Polystyrene plastics is an emerging pollutant affecting plant performance and soil functioning. However, little information is available on the effects of microplastics and nanoplastics on plant root endophytic and rhizospheric soil microbial communities. Here, barley plants were grown in microplastics/nanoplastics -treated soil and the diversity, composition and function of bacteria and fungi in the root and rhizosphere soil were examined. At the seedling stage, greater changes of root endophytes were found compared with rhizosphere microorganisms under the plastic treatments. Nanoplastics decreased the richness and diversity of the fungal community, while microplastics increased the diversity of the root endophytic bacterial community. The network of the bacterial community under nanoplastics showed higher vulnerability while lower complexity than that under the control. However, the bacterial community under microplastics had a relatively higher resistance than the control. For the rhizosphere microbial community, no significant effect of plastics was found on the α-diversity index at the seedling stage. In addition, the nanoplastics resulted in higher sensitivity in the relative abundance and function of rhizosphere soil microbes than root endophytic microbes at the mature stage. Treatments of polystyrene plastics with different particle sizes reprogramed the rhizosphere and root endophytic microbial communities. Different effects of microplastics and nanoplastics were found on the diversity, composition, network structure and function of bacteria and fungi, which might be due to the variation in particle sizes. These results lay a foundation for learning the effects of polystyrene plastics with different particle sizes on the microorganisms in rhizosphere soil and plant roots, which may have important implications for the adaptation of plant-microbial holobiont in polystyrene plastics-polluted soils.

RevDate: 2023-01-09

Baldo L, Tavecchia G, Rotger A, et al (2023)

Insular holobionts: persistence and seasonal plasticity of the Balearic wall lizard (Podarcis lilfordi) gut microbiota.

PeerJ, 11:e14511.

BACKGROUND: Integrative studies of animals and associated microbial assemblages (i.e., the holobiont) are rapidly changing our perspectives on organismal ecology and evolution. Insular vertebrates provide ideal natural systems to understand patterns of host-gut microbiota coevolution, the resilience and plasticity these microbial communities over temporal and spatial scales, and ultimately their role in the host ecological adaptation.

METHODS: Here we used the endemic Balearic wall lizard Podarcis lilfordi to dissect the drivers of the microbial diversity within and across host allopatric populations/islets. By focusing on three extensively studied populations/islets of Mallorca (Spain) and fecal sampling from individually identified lizards along two years (both in spring and autumn), we sorted out the effect of islet, sex, life stage, year and season on the microbiota composition. We further related microbiota diversity to host genetics, trophic ecology and expected annual metabolic changes.

RESULTS: All the three populations showed a remarkable conservation of the major microbial taxonomic profile, while carrying their unique microbial signature at finer level of taxonomic resolution (Amplicon Sequence Variants (ASVs)). Microbiota distances across populations were compatible with both host genetics (based on microsatellites) and trophic niche distances (based on stable isotopes and fecal content). Within populations, a large proportion of ASVs (30-50%) were recurrently found along the four sampling dates. The microbial diversity was strongly marked by seasonality, with no sex effect and a marginal life stage and annual effect. The microbiota showed seasonal fluctuations along the two sampled years, primarily due to changes in the relative abundances of fermentative bacteria (mostly families Lachnospiraceae and Ruminococcaceae), without any major compositional turnover.

CONCLUSIONS: These results support a large resilience of the major compositional aspects of the P. lilfordi gut microbiota over the short-term evolutionary divergence of their host allopatric populations (<10,000 years), but also indicate an undergoing process of parallel diversification of the both host and associated gut microbes. Predictable seasonal dynamics in microbiota diversity suggests a role of microbiota plasticity in the lizards' metabolic adaptation to their resource-constrained insular environments. Overall, our study supports the need for longitudinal and integrative studies of host and associated microbes in natural systems.

RevDate: 2023-01-09

Marcos S, Parejo M, Estonba A, et al (2022)

Recovering High-Quality Host Genomes from Gut Metagenomic Data through Genotype Imputation.

Advanced genetics (Hoboken, N.J.), 3(3):2100065.

Metagenomic datasets of host-associated microbial communities often contain host DNA that is usually discarded because the amount of data is too low for accurate host genetic analyses. However, genotype imputation can be employed to reconstruct host genotypes if a reference panel is available. Here, the performance of a two-step strategy is tested to impute genotypes from four types of reference panels built using different strategies to low-depth host genome data (≈2× coverage) recovered from intestinal samples of two chicken genetic lines. First, imputation accuracy is evaluated in 12 samples for which both low- and high-depth sequencing data are available, obtaining high imputation accuracies for all tested panels (>0.90). Second, the impact of reference panel choice in population genetics statistics on 100 chickens is assessed, all four panels yielding comparable results. In light of the observations, the feasibility and application of the applied imputation strategy are discussed for different species with regard to the host DNA proportion, genomic diversity, and availability of a reference panel. This method enables leveraging insofar discarded host DNA to get insights into the genetic structure of host populations, and in doing so, facilitates the implementation of hologenomic approaches that jointly analyze host and microbial genomic data.

RevDate: 2023-01-09

Lyu D, DL Smith (2022)

The root signals in rhizospheric inter-organismal communications.

Frontiers in plant science, 13:1064058.

Root exudates play a key role in mediating plant-plant and plant-rhizomicrobiome interactions, including regulating biochemical/physiological aspects of plant-associated microorganisms, to enhance host plant growth and resilience. Root exudates can act as signals to reduce the competition from neighboring plants and recruiting/choreographing a wide range of diverse rhizomicrobiome members to make the host plant a good fit with its immediate environment. Root exudate production is a dynamic and key process, but there is a limited understanding of the metabolites or metabolic pathways involved in the inter-organismal communications facilitated by them. Given the well-known symbiotic relationships between plants and associated rhizomicrobiome members, adding root exudates to microbial isolation media may allow some of the large segments of rhizomicrobiome members that are not currently culturable to be grown in vitro. This will provide new insights into how root signals orchestrate associated microbes, will benefit agricultural production in the face of challenges posed by climate change, and will help to sustainably provide food for a growing global human population.

RevDate: 2023-01-09

Rodríguez-Varela R, Moore KHS, Ebenesersdóttir SS, et al (2023)

The genetic history of Scandinavia from the Roman Iron Age to the present.

Cell, 186(1):32-46.e19.

We investigate a 2,000-year genetic transect through Scandinavia spanning the Iron Age to the present, based on 48 new and 249 published ancient genomes and genotypes from 16,638 modern individuals. We find regional variation in the timing and magnitude of gene flow from three sources: the eastern Baltic, the British-Irish Isles, and southern Europe. British-Irish ancestry was widespread in Scandinavia from the Viking period, whereas eastern Baltic ancestry is more localized to Gotland and central Sweden. In some regions, a drop in current levels of external ancestry suggests that ancient immigrants contributed proportionately less to the modern Scandinavian gene pool than indicated by the ancestry of genomes from the Viking and Medieval periods. Finally, we show that a north-south genetic cline that characterizes modern Scandinavians is mainly due to the differential levels of Uralic ancestry and that this cline existed in the Viking Age and possibly earlier.

RevDate: 2023-01-09

Puetz LC, Delmont TO, Aizpurua O, et al (2021)

Gut Microbiota Linked with Reduced Fear of Humans in Red Junglefowl Has Implications for Early Domestication.

Advanced genetics (Hoboken, N.J.), 2(4):2100018.

Domestication of animals can lead to profound phenotypic modifications within short evolutionary time periods, and for many species behavioral selection is likely at the forefront of this process. Animal studies have strongly implicated that the gut microbiome plays a major role in host behavior and cognition through the microbiome-gut-brain axis. Consequently, herein, it is hypothesized that host gut microbiota may be one of the earliest phenotypes to change as wild animals were domesticated. Here, the gut microbiome community in two selected lines of red junglefowl that are selected for either high or low fear of humans up to eight generations is examined. Microbiota profiles reveal taxonomic differences in gut bacteria known to produce neuroactive compounds between the two selection lines. Gut-brain module analysis by means of genome-resolved metagenomics identifies enrichment in the microbial synthesis and degradation potential of metabolites associated with fear extinction and reduces anxiety-like behaviors in low fear fowls. In contrast, high fear fowls are enriched in gut-brain modules from the butyrate and glutamate pathways, metabolites associated with fear conditioning. Overall, the results identify differences in the composition and functional potential of the gut microbiota across selection lines that may provide insights into the mechanistic explanations of the domestication process.

RevDate: 2023-01-09

Margaryan A, Sinding MS, Carøe C, et al (2021)

The genomic origin of Zana of Abkhazia.

Advanced genetics (Hoboken, N.J.), 2(2):e10051.

Enigmatic phenomena have sparked the imagination of people around the globe into creating folkloric creatures. One prime example is Zana of Abkhazia (South Caucasus), a well-documented 19th century female who was captured living wild in the forest. Zana's appearance was sufficiently unusual, that she was referred to by locals as an Almasty-the analog of Bigfoot in the Caucasus. Although the exact location of Zana's burial site was unknown, the grave of her son, Khwit, was identified in 1971. The genomes of Khwit and the alleged Zana skeleton were sequenced to an average depth of ca. 3× using ancient DNA techniques. The identical mtDNA and parent-offspring relationship between the two indicated that the unknown woman was indeed Zana. Population genomic analyses demonstrated that Zana's immediate genetic ancestry can likely be traced to present-day East-African populations. We speculate that Zana might have had a genetic disorder such as congenital generalized hypertrichosis which could partially explain her strange behavior, lack of speech, and long body hair. Our findings elucidate Zana's unfortunate story and provide a clear example of how prejudices of the time led to notions of cryptic hominids that are still held and transmitted by some today.

RevDate: 2023-01-05
CmpDate: 2023-01-05

Wakimoto T (2023)

Biosynthesis of Bioactive Natural Products Derived from Theonellidae Family Marine Sponges.

Chemical & pharmaceutical bulletin, 71(1):1-8.

Marine sponges are among the most primitive animals and often contain unique, biologically active compounds. Several of these compounds have played an important roles as pharmaceutical leads for anti-cancer drugs, such as halichondrin B, which led to the development of an anti-breast cancer drug. Some compounds with remarkable biological activities are accumulated in significantly high concentrations in the sponge. How and why the marine sponges produce and accumulate bioactive natural products are long-standing questions with both biochemical and ecological implications, since in sponges, the animal-microbe symbioses are presumed to be responsible for the biosynthetic machinery, consisting of efficient enzymes and regulatory systems for the specific biological activities of medicinally relevant natural products. In this review, I focus on the chemically rich Theonellidae family sponges and discuss the biosynthesis of bioactive peptides and polyketides. In particular, the biosynthetic pathway of calyculin A suggests that crosstalk between the sponge host and bacterial symbiont confers a chemical defense system on the immobile animal-microbe holobiont.

RevDate: 2022-12-29

Cheng K, Tong M, Cai Z, et al (2022)

Prokaryotic and eukaryotic microbial communities associated with coral species have high host specificity in the South China Sea.

The Science of the total environment pii:S0048-9697(22)08289-4 [Epub ahead of print].

Reef-building corals are well known for their obligate association with Symbiodiniaceae, and an array of other microbes, including bacteria, fungi, and symbiotic algae (i.e., total microbiome), which together form the coral holobiont. The total microbiome plays an intricate part in maintaining the homeostasis of the coral holobiont and is closely associated with host health. However, the composition of the coral associated microbiome and interaction between its different members remains elusive because few analyses have bridged taxonomically disparate groups. This research gaps have prevented a holistic understanding of the total microbiome. Thus, to simultaneously characterize the bacterial, fungal and symbiotic algal communities associated with different coral species, and explore the relationship between these symbionts and coral health, healthy and bleached tissues from four coral species, Acropora muricata, Galaxea fascicularis, Platygyra daedalea, and Pavona explanulata, were collected from the Xisha Islands of the South China Sea. Using high throughput sequencing, a high degree of host-specificity was observed among bacterial, fungal, and algal groups across coral species. There were no obvious changes in the microbial community structure of apparently healthy and bleached corals, but host bleaching allowed colonization of the holobionts by diverse opportunistic microbes, resulting in a significant elevation in the α-diversity of microbial communities. In addition, co-occurrence analysis of the coral microbiota also identified more complex microbial interactions in bleached corals than in healthy ones. In summary, this study characterized the structure of coral-associated microbiomes across four coral species, and systematically studied microbiome differences between healthy and bleached corals. The findings improve our understanding of the heterogeneity of symbiotic microorganisms and the impact of coral's physiological status on its associated microbial communities composition.

RevDate: 2022-12-24

Liu Y, Morelli M, Koskimäki JJ, et al (2022)

Editorial: Role of endophytic bacteria in improving plant stress resistance.

Frontiers in plant science, 13:1106701.

RevDate: 2022-12-23

Nale JY, Thanki AM, Rashid SJ, et al (2022)

Diversity, Dynamics and Therapeutic Application of Clostridioides difficile Bacteriophages.

Viruses, 14(12):.

Clostridioides difficile causes antibiotic-induced diarrhoea and pseudomembranous colitis in humans and animals. Current conventional treatment relies solely on antibiotics, but C. difficile infection (CDI) cases remain persistently high with concomitant increased recurrence often due to the emergence of antibiotic-resistant strains. Antibiotics used in treatment also induce gut microbial imbalance; therefore, novel therapeutics with improved target specificity are being investigated. Bacteriophages (phages) kill bacteria with precision, hence are alternative therapeutics for the targeted eradication of the pathogen. Here, we review current progress in C. difficile phage research. We discuss tested strategies of isolating C. difficile phages directly, and via enrichment methods from various sample types and through antibiotic induction to mediate prophage release. We also summarise phenotypic phage data that reveal their morphological, genetic diversity, and various ways they impact their host physiology and pathogenicity during infection and lysogeny. Furthermore, we describe the therapeutic development of phages through efficacy testing in different in vitro, ex vivo and in vivo infection models. We also discuss genetic modification of phages to prevent horizontal gene transfer and improve lysis efficacy and formulation to enhance stability and delivery of the phages. The goal of this review is to provide a more in-depth understanding of C. difficile phages and theoretical and practical knowledge on pre-clinical, therapeutic evaluation of the safety and effectiveness of phage therapy for CDI.

RevDate: 2022-12-23

Ramos Meyers G, Samouda H, T Bohn (2022)

Short Chain Fatty Acid Metabolism in Relation to Gut Microbiota and Genetic Variability.

Nutrients, 14(24):.

It is widely accepted that the gut microbiota plays a significant role in modulating inflammatory and immune responses of their host. In recent years, the host-microbiota interface has gained relevance in understanding the development of many non-communicable chronic conditions, including cardiovascular disease, cancer, autoimmunity and neurodegeneration. Importantly, dietary fibre (DF) and associated compounds digested by the microbiota and their resulting metabolites, especially short-chain fatty acids (SCFA), were significantly associated with health beneficial effects, such as via proposed anti-inflammatory mechanisms. However, SCFA metabolic pathways are not fully understood. Major steps include production of SCFA by microbiota, uptake in the colonic epithelium, first-pass effects at the liver, followed by biodistribution and metabolism at the host's cellular level. As dietary patterns do not affect all individuals equally, the host genetic makeup may play a role in the metabolic fate of these metabolites, in addition to other factors that might influence the microbiota, such as age, birth through caesarean, medication intake, alcohol and tobacco consumption, pathogen exposure and physical activity. In this article, we review the metabolic pathways of DF, from intake to the intracellular metabolism of fibre-derived products, and identify possible sources of inter-individual variability related to genetic variation. Such variability may be indicative of the phenotypic flexibility in response to diet, and may be predictive of long-term adaptations to dietary factors, including maladaptation and tissue damage, which may develop into disease in individuals with specific predispositions, thus allowing for a better prediction of potential health effects following personalized intervention with DF.

RevDate: 2022-12-23

Rhimi S, Kriaa A, Mariaule V, et al (2022)

The Nexus of Diet, Gut Microbiota and Inflammatory Bowel Diseases in Dogs.

Metabolites, 12(12):.

Canine inflammatory bowel diseases (IBD) are of increasing interest in veterinary medicine. They refer to complex and debilitating conditions of dogs' gastrointestinal tract. Although little evidence for causal inferences is currently available, it is believed that IBD pathophysiology entails intricate interactions between environmental factors, the intestinal immune system, and the microbial communities that colonize the gut. To better understand the mechanisms underlying these disorders, leveraging factors associated with the development of these diseases is imperative. Of these factors, emerging evidence supports the role of dietary patterns as key players influencing the composition and function of gut microbes, with subsequent effects on health and disease. In this review, we particularly focus on addressing IBD in dogs and discuss how specific nutrients may elicit or relieve gut inflammation. Gaining mechanistic insights into such interplay and the underpinning mechanisms is key to inferring dietary recommendations, and setting up new and promising therapeutics.

RevDate: 2022-12-23

Schulz M, Schmitt I, Weber D, et al (2022)

Fungal Host Affects Photosynthesis in a Lichen Holobiont.

Journal of fungi (Basel, Switzerland), 8(12):.

Corals and lichens are iconic examples of photosynthetic holobionts, i.e., ecological and evolutionary units resulting from the tightly integrated association of algae and prokaryotic microbiota with animal or fungal hosts, respectively. While the role of the coral host in modulating photosynthesis has been clarified to a large extent in coral holobionts, the role of the fungal host in this regard is far less understood. Here, we address this question by taking advantage of the recent discovery of highly specific fungal-algal pairings corresponding to climatically adapted ecotypes of the lichen-forming genus Umbilicaria. Specifically, we compared chlorophyll a fluorescence kinetics among lichen thalli consisting of different fungal-algal combinations. We show that photosynthetic performance in these lichens is not only driven by algal genotype, but also by fungal host species identity and intra-host genotype. These findings shed new light on the closely intertwined physiological processes of fungal and algal partners in the lichen symbiosis. Indeed, the specific combinations of fungal and algal genotypes within a lichen individual-and the resulting combined functional phenotype-can be regarded as a response to the environment. Our findings suggest that characterizing the genetic composition of both eukaryotic partners is an important complimentary step to understand and predict the lichen holobiont's responses to environmental change.

RevDate: 2022-12-22

Fontaine SS, KD Kohl (2022)

The microbiome buffers tadpole hosts from heat stress: a hologenomic approach to understand host-microbe interactions under warming.

The Journal of experimental biology pii:286161 [Epub ahead of print].

Phenotypic plasticity is an important strategy that animals employ to respond and adjust to changes in their environment. Plasticity may occur via changes in host gene expression or through functional changes in their microbiomes, which contribute substantially to host physiology. Specifically, the presence and function of host-associated microbes can impact how animals respond to heat stress. We previously demonstrated that "depleted" tadpoles, with artificially disrupted microbiomes, are less tolerant to heat than "colonized" tadpoles, with more natural microbiomes. However, the mechanisms behind these effects are unclear. Here, we compare gene expression profiles of the tadpole gut transcriptome, and tadpole gut microbial metagenome, between colonized and depleted tadpoles under cool or warm conditions. Our goal was to identify differences in host and microbial responses to heat between colonized and depleted tadpoles that might explain their observed differences in heat tolerance. We found that depleted tadpoles exhibited a much stronger degree of host gene expression plasticity in response to heat, while the microbiome of colonized tadpoles was significantly more heat sensitive. These patterns indicate that functional changes in the microbiome in response to heat may allow for a dampened host response, ultimately buffering hosts from the deleterious effects of heat stress. We also identified several specific host and microbial pathways that could be contributing to increased thermal tolerance in colonized tadpoles including amino acid metabolism, vitamin biosynthesis, and ROS scavenging pathways. Our results demonstrate that the microbiome influences host plasticity and the response of hosts to environmental stressors.

RevDate: 2022-12-22

Chen L, Li Z, Wu B, et al (2022)

Progressive evolution of secondary aquatic adaptation in hippos and cetaceans.

Cell discovery, 8(1):134.

RevDate: 2022-12-20

Espino-Vázquez AN, Córdova-López G, Cabrera-Rangel JF, et al (2023)

The Rhizopus Holobiont: A Model to Decipher Fungal-Bacterial-Viral Symbioses.

Methods in molecular biology (Clifton, N.J.), 2610:137-147.

Rhizopus microsporus is an early-diverging fungal species that inhabits the soil, is used for the fermentation of diverse Asian and African foods, and can be a pathogen of plants, animals, and humans.Toxin-producing strains of R. microsporus live in symbiosis with Gram-negative betaproteobacteria from the genus Mycetohabitans (Burkholderia sensu lato). These bacterial endosymbionts increase the metabolic plasticity of the fungal holobiont by producing the "mycotoxins," control their asexual reproduction, and influence their sexual success. Recently, we identified two viruses of the genus Narnavirus in some R. microsporus strains that harbor Mycetohabitans. By eliminating bacteria and/or viruses from host R. microsporus strains, we have been able to study the role of these symbionts in fungal biology. Remarkably, the absence of these bacterial and viral symbionts decreases sexual reproduction. In this chapter, the method developed to eliminate and genotype the Narnavirus RmNV-20S and RmNV-23S in R. microsporus is described in detail.

RevDate: 2022-12-15
CmpDate: 2022-12-15

Sangiorgio D, Cellini A, Donati I, et al (2022)

Taxonomical and functional composition of strawberry microbiome is genotype-dependent.

Journal of advanced research, 42:189-204.

INTRODUCTION: Specific microbial communities are associated to host plants, influencing their phenotype and fitness.Despite the rising interest in plant microbiome, the role of microbial communities associated with perennial fruit plants remains overlooked.

OBJECTIVES: This work provides the first comprehensive descriptionof the taxonomical and functional bacterial and fungal microbiota of below- and above-ground organsof three commercially important strawberry genotypes under cultural conditions.

METHODS: Strawberry-associatedfungal and bacterial microbiomes were characterised by Next-Generation Sequencing and the potential functions expressed by the bacterial microbiome were analysed by both in silico and in vitro characterisation of plant growth-promoting abilities of native bacteria. Additionally, the association between the strawberry microbiome, plant disease tolerance, plant mineral nutrient content, and fruit quality was investigated.

RESULTS: Results showed that thestrawberry core microbiome included 24 bacteria and 15 fungal operational taxonomicunits (OTUs).However, plant organ and genotype had a significant role in determining the taxonomical and functional composition of microbial communities. Interestingly, the cultivar with the highesttolerance against powdery mildew and leaf spot and the highest fruit productivity was the only one able to ubiquitously recruit the beneficial bacterium, Pseudomonasfluorescens, and to establish a mutualistic symbiosis with the arbuscular mycorrhizaRhizophagus irregularis.

CONCLUSION: This work sheds light on the interaction of cultivated strawberry genotypes with a variety of microbes and highlights the importance of their applications to increase the sustainability of fruit crop production.

RevDate: 2022-12-13

Biggs E, Taylor MW, DMRL Middleton (2022)

Beyond the theory: from holobiont concept to microbiome engineering.

Environmental microbiology [Epub ahead of print].

Holobiont research has increasingly moved from descriptive studies to sophisticated field- and laboratory-based manipulations, however the extent to which changes in the holobiont persist remains largely unknown. In this Burning Question, we ask whether the underlying principles of the holobiont concept, whereby an externally applied evolutionary pressure can lead to a beneficial change in host-associated microbial community composition, could be used to facilitate microbiome engineering and thereby addition of a new ecosystem service that persists across generations. The answer to this question has potential implications for diverse fields including symbiosis, conservation and biotechnology.

RevDate: 2022-12-12

Liberman R, Benayahu Y, D Huchon (2022)

Octocorals in the Gulf of Aqaba exhibit high photosymbiont fidelity.

Frontiers in microbiology, 13:1005471.

Symbiotic associations, widespread in terrestrial and marine ecosystems, are of considerable ecological importance. Many tropical coral species are holobionts, formed by the obligate association between a cnidarian host and endosymbiotic dinoflagellates of the family Symbiodiniaceae. The latter are abundant on coral reefs from very shallow water down to the upper mesophotic zone (30-70 m). The research on scleractinians has revealed that the photosymbiont lineages present in the cnidarian host play an important role in the coral's ability to thrive under different environmental conditions, such as light regime and temperature. However, little is known regarding octocoral photosymbionts, and in particular regarding those found deeper than 30 m. Here, we used ribosomal (ITS2) and chloroplast (23S) markers to uncover, for the first time, the dominant Symbiodiniaceae taxa present in 19 mesophotic octocoral species (30-70 m depth) from the Gulf of Aqaba/Eilat (northern Red Sea). In addition, using high-throughput sequencing of the ITS2 region we characterized both the dominant and the rare Symbiodiniaceae lineages found in several species across depth. The phylogenetic analyses of both markers were in agreement and revealed that most of the studied mesophotic octocorals host the genus Cladocopium. Litophyton spp. and Klyxum utinomii were exceptions, as they harbored Symbiodinium and Durusdinium photosymbionts, respectively. While the dominant algal lineage of each coral species did not vary across depth, the endosymbiont community structure significantly differed between host species, as well as between different depths for some host species. The findings from this study contribute to the growing global-catalogue of Cnidaria-Symbiodiniaceae associations. Unravelling the Symbiodiniaceae composition in octocoral holobionts across environmental gradients, depth in particular, may enable a better understanding of how specialized those associations are, and to what extent coral holobionts are able to modify their photosymbionts.

RevDate: 2022-12-12

Hodžić A, Dheilly NM, Cabezas-Cruz A, et al (2022)

The helminth holobiont: a multidimensional host-parasite-microbiota interaction.

Trends in parasitology pii:S1471-4922(22)00285-9 [Epub ahead of print].

Gastrointestinal helminths have developed multiple mechanisms by which they manipulate the host microbiome to make a favorable environment for their long-term survival. While the impact of helminth infections on vertebrate host immunity and its gut microbiota is relatively well studied, little is known about the structure and functioning of microbial populations supported by metazoan parasites. Here we argue that an integrated understanding of the helminth-associated microbiome and its role in the host disease pathogenesis may facilitate the discovery of specific microbial and/or genetic patterns critical for parasite biology and subsequently pave the way for the development of alternative control strategies against parasites and parasitic disease.

RevDate: 2022-12-10

Zhu Z, Liu Y, Hu H, et al (2022)

Nasonia-microbiome associations: a model for evolutionary hologenomics research.

Trends in parasitology pii:S1471-4922(22)00278-1 [Epub ahead of print].

In recent years, with the development of microbial research technologies, microbiota research has received widespread attention. The parasitoid wasp genus Nasonia is a good model organism for studying insect behavior, development, evolutionary genetics, speciation, and symbiosis. This review describes key advances and progress in the field of the Nasonia microbiome interactions. We provide an overview of the advantages of Nasonia as a model organism for microbiome studies, list research methods to study the Nasonia microbiome, and discuss recent discoveries in Nasonia microbiome research. This summary of the complexities of Nasonia-microbiome relationships will help to contribute to a better understanding of the interactions between animals and their microbiomes and establish a clear research direction for Nasonia-microbiome interactions in the future.

RevDate: 2022-12-10

Gruet C, Abrouk D, Börner A, et al (2022)

Wheat genome architecture influences interactions with phytobeneficial microbial functional groups in the rhizosphere.

Plant, cell & environment [Epub ahead of print].

Wheat has undergone a complex evolutionary history, which led to allopolyploidization and the hexaploid bread wheat Triticum aestivum. However, the significance of wheat genomic architecture for beneficial plant-microbe interactions is poorly understood, especially from a functional standpoint. In this study, we tested the hypothesis that wheat genomic architecture was an overriding factor determining root recruitment of microorganisms with particular plant-beneficial traits. We chose five wheat species representing genomic profiles AA (Triticum urartu), BB {SS} (Aegilops speltoides), DD (Aegilops tauschii), AABB (Triticum dicoccon) and AABBDD (Triticum aestivum) and assessed by qPCR their ability to interact with free-nitrogen fixers, 1-aminocyclopropane-1-carboxylate deaminase producers, 2,4-diacetylphloroglucinol producers and auxin producers via the phenylpyruvate decarboxylase pathway, in combination with Illumina MiSeq metabarcoding analysis of N fixers (and of the total bacterial community). We found that the abundance of the microbial functional groups could fluctuate according to wheat genomic profile, as did the total bacterial abundance. N fixer diversity and total bacterial diversity were also influenced significantly by wheat genomic profile. Often, rather similar results were obtained for genomes DD (Ae. tauschii) and AABBDD (T. aestivum), pointing for the first time that the D genome could be particularly important for wheat-bacteria interactions. This article is protected by copyright. All rights reserved.

RevDate: 2022-12-09

Zhang X, Ma YN, Wang X, et al (2022)

Dynamics of rice microbiomes reveal core vertically transmitted seed endophytes.

Microbiome, 10(1):216.

BACKGROUND: Plants and their associated microbiota constitute an assemblage of species known as holobionts. The plant seed microbiome plays an important role in nutrient uptake and stress attenuation. However, the core vertically transmitted endophytes remain largely unexplored.

RESULTS: To gain valuable insights into the vertical transmission of rice seed core endophytes, we conducted a large-scale analysis of the microbiomes of two generations of six different rice varieties from five microhabitats (bulk soil, rhizosphere, root, stem, and seed) from four geographic locations. We showed that the microhabitat rather than the geographic location and rice variety was the primary driver of the rice microbiome assemblage. The diversity and network complexity of the rice-associated microbiome decreased steadily from far to near the roots, rice exterior to interior, and from belowground to aboveground niches. Remarkably, the microbiomes of the roots, stems, and seeds of the rice interior compartments were not greatly influenced by the external environment. The core bacterial endophytes of rice were primarily comprised of 14 amplicon sequence variants (ASVs), 10 of which, especially ASV_2 (Pantoea) and ASV_48 (Xanthomonas), were identified as potentially vertically transmitted taxa because they existed across generations, were rarely present in exterior rice microhabitats, and were frequently isolated from rice seeds. The genome sequences of Pantoea and Xanthomonas isolated from the parental and offspring seeds showed a high degree of average nucleotide and core protein identity, indicating vertical transmission of seed endophytes across generations. In silico prediction indicated that the seed endophytes Pantoea and Xanthomonas possessed streamlined genomes with short lengths, low-complexity metabolism, and various plant growth-promoting traits. We also found that all strains of Pantoea and Xanthomonas exhibited cellulase activity and produced indole-3-acetic acid. However, most strains exhibited insignificant antagonism to the major pathogens of rice, such as Magnaporthe oryzae and X. oryzae pv. oryzae.

CONCLUSION: Overall, our study revealed that microhabitats, rather than site-specific environmental factors or host varieties, shape the rice microbiome. We discovered the vertically transmitted profiles and keystone taxa of the rice microbiome, which led to the isolation of culturable seed endophytes and investigation of their potential roles in plant-microbiome interactions. Our results provide insights on vertically transmitted microbiota and suggest new avenues for improving plant fitness via the manipulation of seed-associated microbiomes.  Video Abstract.

RevDate: 2022-12-09

Nguyen BT, Dumack K, Trivedi P, et al (2022)

Plant associated protists - untapped promising candidates for agrifood tools.

Environmental microbiology [Epub ahead of print].

The importance of host-associated microorganisms and their biotic interactions for plant health and performance has been increasingly acknowledged. Protists, main predators and regulators of bacteria and fungi, are abundant and ubiquitous eukaryotes in terrestrial ecosystems. Protists are considered to benefit plant health and performance, but the community structure and functions of plant-associated protists remain surprisingly underexplored. Harnessing plant-associated protists and other microbes can potentially enhance plant health and productivity and sustain healthy food and agriculture systems. In this review, we summarize the knowledge of multifunctionality of protists and their interactions with other microbes in plant hosts, and propose a future framework to study plant-associated protists and utilize protists as agrifood tools for benefiting agricultural production. This article is protected by copyright. All rights reserved.

RevDate: 2022-12-08

Jochum M, Lee MD, Curry K, et al (2022)

Analysis of bronchoalveolar lavage fluid metatranscriptomes among patients with COVID-19 disease.

Scientific reports, 12(1):21125.

To better understand the potential relationship between COVID-19 disease and hologenome microbial community dynamics and functional profiles, we conducted a multivariate taxonomic and functional microbiome comparison of publicly available human bronchoalveolar lavage fluid (BALF) metatranscriptome samples amongst COVID-19 (n = 32), community acquired pneumonia (CAP) (n = 25), and uninfected samples (n = 29). We then performed a stratified analysis based on mortality amongst the COVID-19 cohort with known outcomes of deceased (n = 10) versus survived (n = 15). Our overarching hypothesis was that there are detectable and functionally significant relationships between BALF microbial metatranscriptomes and the severity of COVID-19 disease onset and progression. We observed 34 functionally discriminant gene ontology (GO) terms in COVID-19 disease compared to the CAP and uninfected cohorts, and 21 GO terms functionally discriminant to COVID-19 mortality (q < 0.05). GO terms enriched in the COVID-19 disease cohort included hydrolase activity, and significant GO terms under the parental terms of biological regulation, viral process, and interspecies interaction between organisms. Notable GO terms associated with COVID-19 mortality included nucleobase-containing compound biosynthetic process, organonitrogen compound catabolic process, pyrimidine-containing compound biosynthetic process, and DNA recombination, RNA binding, magnesium and zinc ion binding, oxidoreductase activity, and endopeptidase activity. A Dirichlet multinomial mixtures clustering analysis resulted in a best model fit using three distinct clusters that were significantly associated with COVID-19 disease and mortality. We additionally observed discriminant taxonomic differences associated with COVID-19 disease and mortality in the genus Sphingomonas, belonging to the Sphingomonadacae family, Variovorax, belonging to the Comamonadaceae family, and in the class Bacteroidia, belonging to the order Bacteroidales. To our knowledge, this is the first study to evaluate significant differences in taxonomic and functional signatures between BALF metatranscriptomes from COVID-19, CAP, and uninfected cohorts, as well as associating these taxa and microbial gene functions with COVID-19 mortality. Collectively, while this data does not speak to causality nor directionality of the association, it does demonstrate a significant relationship between the human microbiome and COVID-19. The results from this study have rendered testable hypotheses that warrant further investigation to better understand the causality and directionality of host-microbiome-pathogen interactions.

RevDate: 2022-12-07
CmpDate: 2022-12-07

Wang HY, Kang CZ, Wang YF, et al (2022)

[Medicinal plant microbiome: advances and prospects].

Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica, 47(20):5397-5405.

Medicinal plants are the main source of clinical medication in traditional Chinese medicine(TCM). China has achieved large-scale cultivation and production of medicinal plants. As an important resource for the sustainable development of agriculture in the future, microorganisms can also promote the green, ecological and high-quality development of Chinese medicine agriculture. However, research on the medicinal plant microbiome is still limited. Therefore, based on the development timeline of microbiome research, the present study reviewed the origin, technology, and hotspots of microbiome research and proposed some suggestions for future research according to the advances in medicinal plant microbiome.(1)Systematic investigation of medicinal plant microbiome on the species, genus, and family levels should be carried out on the medicinal plants of different chemotypes in order to reveal the coevolution of the microorganisms and their host plants.(2)Spatial and temporal research on medicinal plant microbiome should be performed to reveal the effects of microorganisms on the growth, development, and secondary metabolite accumulation of medicinal plants, as well as the underlying mechanisms.(3)Model medicinal plant species should be selected and microorganism-plant interaction research models should be established.(4)Core microbiome of medicinal plants should be explored for the future application of crucial microbes in the sustaina-ble agriculture of Chinese medicine.(5)Breeding of medicinal plant-associated microbes should be carried out to lay the foundation for novel medicinal plant breeding strategies.(6)High-throughput sequencing, traditional incubation, and isolation of microbes should be combined to study medicinal plant microbiome, thereby promoting the exploitation and application of uncultured microbial strains.(7)Platforms for the preservation of medicinal plant-associated microbe strains and data of their metabolites should be established and the exchange of information and cooperation between these platforms should be subsequently enhanced. With these suggestions, the efficient and rapid development of medicinal plant microbiome research is expected to be promoted.

RevDate: 2022-12-04

Kalra R, Conlan XA, M Goel (2022)

Recent advances in research for potential utilization of unexplored lichen metabolites.

Biotechnology advances pii:S0734-9750(22)00168-9 [Epub ahead of print].

Several research studies have shown that lichens are productive organisms for the synthesis of a broad range of secondary metabolites. Lichens are a self-sustainable stable microbial ecosystem comprising an exhabitant fungal partner (mycobiont) and at least one or more photosynthetic partners (photobiont). The successful symbiosis is responsible for their persistence throughout time and allows all the partners (holobionts) to thrive in many extreme habitats, where without the synergistic relationship they would be rare or non-existent. The ability to survive in harsh conditions can be directly correlated with the production of some unique metabolites. Despite the potential applications, these unique metabolites have been underutilised by pharmaceutical and agrochemical industries due to their slow growth, low biomass availability and technical challenges involved in their artificial cultivation. However, recent development of biotechnological tools such as molecular phylogenetics, modern tissue culture techniques, metabolomics and molecular engineering are opening up a new opportunity to exploit these compounds within the lichen holobiome for industrial applications. This review also highlights the recent advances in culturing the symbionts and the computational and molecular genetics approaches of lichen gene regulation recognized for the enhanced production of target metabolites. The recent development of multi-omics novel biodiscovery strategies aided by synthetic biology in order to study the heterologous expressed lichen-derived biosynthetic gene clusters in a cultivatable host offers a promising means for a sustainable supply of specialized metabolites.

RevDate: 2022-11-29

Sylvain FÉ, Leroux N, Normandeau É, et al (2022)

Genomic and Environmental Factors Shape the Active Gill Bacterial Community of an Amazonian Teleost Holobiont.

Microbiology spectrum [Epub ahead of print].

Fish bacterial communities provide functions critical for their host's survival in contrasting environments. These communities are sensitive to environmental-specific factors (i.e., physicochemical parameters, bacterioplankton), and host-specific factors (i.e., host genetic background). The relative contribution of these factors shaping Amazonian fish bacterial communities is largely unknown. Here, we investigated this topic by analyzing the gill bacterial communities of 240 wild flag cichlids (Mesonauta festivus) from 4 different populations (genetic clusters) distributed across 12 sites in 2 contrasting water types (ion-poor/acidic black water and ion-rich/circumneutral white water). Transcriptionally active gill bacterial communities were characterized by a 16S rRNA metabarcoding approach carried on RNA extractions. They were analyzed using comprehensive data sets from the hosts genetic background (Genotyping-By-Sequencing), the bacterioplankton (16S rRNA) and a set of 34 environmental parameters. Results show that the taxonomic structure of 16S rRNA gene transcripts libraries were significantly different between the 4 genetic clusters and also between the 2 water types. However, results suggest that the contribution of the host's genetic background was relatively weak in comparison to the environment-related factors in structuring the relative abundance of different active gill bacteria species. This finding was also confirmed by a mixed-effects modeling analysis, which indicated that the dissimilarity between the taxonomic structure of bacterioplanktonic communities possessed the best explicative power regarding the dissimilarity between gill bacterial communities' structure, while pairwise fixation indexes (FST) from the hosts' genetic data only had a weak explicative power. We discuss these results in terms of bacterial community assembly processes and flag cichlid fish ecology. IMPORTANCE Host-associated microbial communities respond to factors specific to the host physiology, genetic backgrounds, and life history. However, these communities also show different degrees of sensitivity to environment-dependent factors, such as abiotic physico-chemical parameters and ecological interactions. The relative importance of host- versus environment-associated factors in shaping teleost bacterial communities is still understudied and is paramount for their conservation and aquaculture. Here, we studied the relative importance of host- and environment-associated factors structuring teleost bacterial communities using gill samples from a wild Amazonian teleost model (Mesonauta festivus) sampled in contrasting habitats along a 1500 km section of the Amazonian basin, thus ensuring high genetic diversity. Results showed that the contribution of the host's genetic background was weak compared to environment-related bacterioplanktonic communities in shaping gill bacterial assemblages, thereby suggesting that our understanding of teleost microbiome assembly could benefit from further studies focused on the ecological interplay between host-associated and free-living communities.

RevDate: 2022-11-26

Travesso M, Missionário M, Cruz S, et al (2022)

Combined effect of marine heatwaves and light intensity on the cellular stress response and photophysiology of the leather coral Sarcophyton cf. glaucum.

The Science of the total environment pii:S0048-9697(22)07562-3 [Epub ahead of print].

Marine heatwaves (MHW) are threatening tropical coral reef ecosystems, leading to mass bleaching events worldwide. The combination of heat stress with high irradiance is known to shape the health and redox status of corals, but research is biased toward scleractinian corals, while much less is known on tropical symbiotic soft corals. Here, we evaluated the cellular stress response and the photophysiological performance of the soft coral Sarcophyton cf. glaucum, popularly termed as leather coral, under different global change scenarios. Corals were exposed to different light intensities (high light, low light, ∼662 and 253 μmol photons m[-2] s[-1]) for 30 days (time-point 1) and a subsequent MHW simulation was carried out for 10 days (control 26 vs 32 °C) (time-point 2). Subsequently, corals were returned to control temperature and allowed to recover for 30 days (time-point 3). Photophysiological performance (maximum quantum yield of photosystem II (Fv/Fm), a measure of photosynthetic activity; dark-level fluorescence (F0), as a proxy of chlorophyll a content (Chl a); and zooxanthellae density) and stress biomarkers (total protein, antioxidants, lipid peroxidation, ubiquitin, and heat shock protein 70) were assessed in corals at these three time-points. Corals were especially sensitive to the combination of heat and high light stress, experiencing a decrease in their photosynthetic efficiency under these conditions. Heat stress resulted in bleaching via zooxanthellae loss while high light stress led to pigment (Chl a) loss. This species' antioxidant defenses, and protein degradation were particularly enhanced under heat stress. A recovery was clear for molecular parameters after 30 days of recovery, whereby photophysiological performance required more time to return to basal levels. We conclude that soft corals distributed along intertidal areas, where the light intensity is high, could be especially vulnerable to marine heatwave events, highlighting the need to direct conservation efforts toward these organisms.

RevDate: 2022-11-29
CmpDate: 2022-11-29

Schaack B, Hindré T, Quansah N, et al (2022)

Microbiota-Derived Extracellular Vesicles Detected in Human Blood from Healthy Donors.

International journal of molecular sciences, 23(22): pii:ijms232213787.

The microbiota constitutes an important part of the holobiont in which extracellular vesicles (EVs) are key players in health, especially regarding inter- and intra-kingdom communications. Analysis of EVs from the red blood cell concentrates of healthy donors revealed variable amounts of OmpA and LPS in 12 of the 14 analyzed samples, providing indirect experimental evidence of the presence of microbiota EVs in human circulating blood in the absence of barrier disruption. To investigate the role of these microbiota EVs, we tracked the fusion of fluorescent Escherichia coli EVs with blood mononuclear cells and showed that, in the circulating blood, these EVs interacted almost exclusively with monocytes. This study demonstrates that bacterial EVs constitute critical elements of the host-microbiota cellular communication. The analysis of bacterial EVs should thus be systematically included in any characterization of human EVs.

RevDate: 2022-11-29
CmpDate: 2022-11-29

Sampson TR (2022)

Introduction: Unraveling the complex contributions of indigenous microbes to neurological health and disease.

International review of neurobiology, 167:xi-xvi.

The complex interactions between the human body and its indigenous microbes have come into focus as key mediators of neurological health. With both established and emerging association studies, alterations to the gut microbiome are observed to co-occur with many neurological diseases. Whether these associations are due to microbiome-mediated contributions to human health or an effect of the neurological disease itself is largely unknown across conditions. Here, we have collected contributions from a broad group of experts that highlight gut microbiome impacts across numerous neurological conditions. Ranging from neurodevelopmental disorders, to Parkinson's disease, Alzheimer's disease, epilepsy, traumatic injury, and amyotrophic lateral sclerosis, among others, we hope to provide a clearer picture of how our indigenous microbes impact neurological health. The study of these indigenous microbes will continue to reveal critical mechanisms that may 1 day be exploited for therapeutic benefits against these recalcitrant diseases.

RevDate: 2022-11-29
CmpDate: 2022-11-29

Payami H (2022)

The many genomes of Parkinson's disease.

International review of neurobiology, 167:59-80.

Genetic component of Parkinson's disease, once firmly believed non-existent, involves the human genome, mitochondrial genome, and the microbiome. Understanding the genomics of PD requires identification of PD-relevant genes and learning how they interact within the hologenome and with their environment. This chapter is an evidence-based perspective of a geneticist on how far we have come in this endeavor. The contemporary scientific society started with a naive and simplistic view of PD, evolved to accept that Parkinson's disease is probably the most complex disease there is, the progress we have made in discovering the genes and elucidating their functions, and now assembling the parts to create the whole.

RevDate: 2022-11-28
CmpDate: 2022-11-28

Thuesen NH, Klausen MS, Gopalakrishnan S, et al (2022)

Benchmarking freely available HLA typing algorithms across varying genes, coverages and typing resolutions.

Frontiers in immunology, 13:987655.

Identifying the specific human leukocyte antigen (HLA) allele combination of an individual is crucial in organ donation, risk assessment of autoimmune and infectious diseases and cancer immunotherapy. However, due to the high genetic polymorphism in this region, HLA typing requires specialized methods. We investigated the performance of five next-generation sequencing (NGS) based HLA typing tools with a non-restricted license namely HLA*LA, Optitype, HISAT-genotype, Kourami and STC-Seq. This evaluation was done for the five HLA loci, HLA-A, -B, -C, -DRB1 and -DQB1 using whole-exome sequencing (WES) samples from 829 individuals. The robustness of the tools to lower depth of coverage (DOC) was evaluated by subsampling and HLA typing 230 WES samples at DOC ranging from 1X to 100X. The HLA typing accuracy was measured across four typing resolutions. Among these, we present two clinically-relevant typing resolutions (P group and pseudo-sequence), which specifically focus on the peptide binding region. On average, across the five HLA loci examined, HLA*LA was found to have the highest typing accuracy. For the individual loci, HLA-A, -B and -C, Optitype's typing accuracy was the highest and HLA*LA had the highest typing accuracy for HLA-DRB1 and -DQB1. The tools' robustness to lower DOC data varied widely and further depended on the specific HLA locus. For all Class I loci, Optitype had a typing accuracy above 95% (according to the modification of the amino acids in the functionally relevant portion of the HLA molecule) at 50X, but increasing the DOC beyond even 100X could still improve the typing accuracy of HISAT-genotype, Kourami, and STC-seq across all five HLA loci as well as HLA*LA's typing accuracy for HLA-DQB1. HLA typing is also used in studies of ancient DNA (aDNA), which is often based on sequencing data with lower quality and DOC. Interestingly, we found that Optitype's typing accuracy is not notably impaired by short read length or by DNA damage, which is typical of aDNA, as long as the DOC is sufficiently high.

RevDate: 2022-11-26

Zhu W, Zhu M, Liu X, et al (2022)

Adaptive changes of coral Galaxea fascicularis holobiont in response to nearshore stress.

Frontiers in microbiology, 13:1052776.

Global change and local stressors are simultaneously affecting the nearshore corals, and microbiome flexibility may assist corals in thriving under such multiple stressors. Here, we investigated the effects of various environmental variables on Galaxea fascicularis holobiont from nearshore and offshore reefs. These nearshore reefs were more turbid, eutrophic, and warm than offshore reefs. However, coral physiological parameters did not differ significantly. Corals under stressful nearshore environments had low symbiont diversity and selected more tolerant Symbiodiniaceae. The bacterial diversity of offshore corals was significantly higher, and their community composition varied obviously. Diffusion limitations and environmental heterogeneity were essential in structuring microbial communities. Functional annotation analysis demonstrated significant differences between nearshore and offshore corals in bacterial functional groups. Environmental stress significantly reduced the complexity and connectivity of bacterial networks, and the abundances of keystone taxa altered considerably. These results indicated that corals could thrive nearshore through holobiont plasticity to cope with multiple environmental stresses.

RevDate: 2022-11-29

Duval C, Marie B, Foucault P, et al (2022)

Establishment of the Bacterial Microbiota in a Lab-Reared Model Teleost Fish, the Medaka Oryzias latipes.

Microorganisms, 10(11):.

Oryzias latipes is an important model organism for physiology, genetics, and developmental studies, and has also emerged as a relevant vertebrate model for aquatic ecotoxicology. Knowledge regarding its associated microbiota on the other hand is still scarce and limited to adults, despite the relevance of the associated microbiome to the host's biology. This study provides the first insights into the establishment of bacterial microbiota during early developmental stages of laboratory-reared medaka using a 16S-rRNA-sequencing-based approach. Major shifts in community compositions are observed, from a Proteobacteria-dominated community in larvae and juveniles to a more phylum-diverse community towards adulthood, with no obvious difference between female and male specimens. Major bacterial taxa found in adults, including genera Cetobacterium and ZOR0006, establish progressively and are rare during early stages. Dominance shifts are comparable to those documented in another major model teleost, the zebrafish. Results from this study provide a basis for future work investigating the influence of medaka-associated bacteria during host development.

RevDate: 2022-11-23

Fujiwara F, Miyazawa K, Nihei N, et al (2022)

Agroecosystem Engineering Extended from Plant-Microbe Interactions Revealed by Multi-Omics Data.

Bioscience, biotechnology, and biochemistry pii:6843571 [Epub ahead of print].

In an agroecosystem, plants and microbes coexist and interact with environmental factors such as climate, soil, and pests. However, agricultural practices that depend on chemical fertilizers, pesticides, and frequent tillage often disrupt the beneficial interactions in the agroecosystem. To reconcile the improvement of crop performance and reduction in environmental impacts in agriculture, we need to understand the functions of the complex interactions and develop an agricultural system that can maximize the potential benefits of the agroecosystem. Therefore, we are developing a system called the agroecosystem engineering system, which aims to optimize the interactions between crops, microbes, and environmental factors, using multi-omics analysis. This review first summarizes the progress and examples of omics approaches, including multi-omics analysis, to reveal complex interactions in the agroecosystem. The latter half of this review discusses the prospects of data analysis approaches in the agroecosystem engineering system, including causal network analysis and predictive modeling.

RevDate: 2022-11-22
CmpDate: 2022-11-22

Scorrano G, Nielsen SH, Vetro DL, et al (2022)

Genomic ancestry, diet and microbiomes of Upper Palaeolithic hunter-gatherers from San Teodoro cave.

Communications biology, 5(1):1262.

Recent improvements in the analysis of ancient biomolecules from human remains and associated dental calculus have provided new insights into the prehistoric diet and genetic diversity of our species. Here we present a multi-omics study, integrating metagenomic and proteomic analyses of dental calculus, and human ancient DNA analysis of the petrous bones of two post-Last Glacial Maximum (LGM) individuals from San Teodoro cave (Italy), to reconstruct their lifestyle and the post-LGM resettlement of Europe. Our analyses show genetic homogeneity in Sicily during the Palaeolithic, representing a hitherto unknown Italian genetic lineage within the previously identified Villabruna cluster. We argue that this lineage took refuge in Italy during the LGM, followed by a subsequent spread to central-western Europe. Analysis of dental calculus showed a diet rich in animal proteins which is also reflected on the oral microbiome composition. Our results demonstrate the power of this approach in the study of prehistoric humans and will enable future research to reach a more holistic understanding of the population dynamics and ecology.

RevDate: 2022-12-07
CmpDate: 2022-12-07

Pei Y, Chen S, Diao X, et al (2023)

Deciphering the disturbance mechanism of BaP on the symbiosis of Montipora digitata via 4D-Proteomics approach.

Chemosphere, 312(Pt 1):137223.

The coral holobiont is mainly composed of coral polyps, zooxanthellae, and coral symbiotic microorganisms, which form the basis of coral reef ecosystems. In recent years, the severe degradation of coral reefs caused by climate warming and environmental pollution has aroused widespread concern. Benzo(a)pyrene (BaP) is a widely distributed pollutant in the environment. However, the underlying mechanisms of coral symbiosis destruction due to the stress of BaP are not well understood. In this study, diaPASEF proteomics and 16S rRNA amplicon pyrosequencing technology were used to reveal the effects of 50 μg/L BaP on Montipora digitate. Data analysis was performed from the perspective of the main symbionts of M. digitata (coral polyps, zooxanthellae, and coral symbiotic microorganisms). The results showed that BaP impaired cellular antioxidant capacity by disrupting the GSH/GSSG cycle, and sustained stress causes severe impairment of energy metabolism and protein degradation in coral polyps. In zooxanthellae, BaP downregulated the protein expression of SOD2 and mtHSP70, which then resulted in oxidative free radical accumulation and apoptosis. For coral symbiotic microorganisms, BaP altered the community structure of microorganisms and decreased immunity. Coral symbiotic microorganisms adapted to the stress of BaP by adjusting energy metabolism and enhancing extracellular electron transfer. BaP adversely affected the three main symbionts of M. digitata via different mechanisms. Decreased antioxidant capacity is a common cause of damages to coral polyps and zooxanthellae, whereas coral symbiotic microorganisms are able to appropriately adapt to oxidative stress. This study assessed the effects of BaP on corals from a symbiotic perspective, which is more comprehensive and reliable. At the same time, data from the study supports new directions for coral research and coral reef protection.

RevDate: 2022-11-12

Paulino GVB, Félix CR, da Silva Oliveira FA, et al (2022)

Microbiota of healthy and bleached corals of the species Siderastrea stellata in response to river influx and seasonality in Brazilian northeast.

Environmental science and pollution research international [Epub ahead of print].

Although coral bleaching is increasing worldwide due to warming oceans exacerbated by climate change, there has been a growing recognition that local stressors may play an additional role. Important stressors include the physicochemical and microbiological influences that are related to river runoff. Here, we investigated the microbiota associated to mucus and tissue of endemic coral Siderastrea stellata, collected from Brazilian northeast coral reefs of Barra de Santo Antônio (subject to river runoff) and Maragogi (minimal river runoff) during both the rainy and dry seasons. We sequenced the V4 region of 16S rDNA and used multiple R packages to process raw data and performed statistical analysis to reveal the microbial community structure composition and functional predictions. Major dissimilarities between microbial communities were related to seasonality, while healthy and bleached specimens were mainly associated with the enrichment of several less abundant taxa involved in specific metabolic functions, mainly related to the nitrogen cycle. We were not able to observe the dominance of groups that has been previously associated with bleachings, such as Vibrionaceae or Burkholderiaceae. The influx of freshwater appears to increase the homogeneity between individuals in Barra de Santo Antonio, especially during the rainy season. By contrast, we observed an increased homogeneity between samples in Maragogi during the dry season. Understanding the dynamics of the coral microbiota and how bleaching appears in response to specific environmental variables, in addition to determining the conditions that lead to a more robust coral microbiota, is essential for choosing the most appropriate area and conservation methods, for example.

RevDate: 2022-11-17

Bunyoo C, Roongsattham P, Khumwan S, et al (2022)

Dynamic Alteration of Microbial Communities of Duckweeds from Nature to Nutrient-Deficient Condition.

Plants (Basel, Switzerland), 11(21):.

Duckweeds live with complex assemblages of microbes as holobionts that play an important role in duckweed growth and phytoremediation ability. In this study, the structure and diversity of duckweed-associated bacteria (DAB) among four duckweed subtypes under natural and nutrient-deficient conditions were investigated using V3-V4 16S rRNA amplicon sequencing. High throughput sequencing analysis indicated that phylum Proteobacteria was predominant in across duckweed samples. A total of 24 microbial genera were identified as a core microbiome that presented in high abundance with consistent proportions across all duckweed subtypes. The most abundant microbes belonged to the genus Rhodobacter, followed by other common DAB, including Acinetobacter, Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, and Pseudomonas. After nutrient-deficient stress, diversity of microbial communities was significantly deceased. However, the relative abundance of Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium, Pelomonas, Roseateles and Novosphingobium were significantly enhanced in stressed duckweeds. Functional prediction of the metagenome data displayed the relative abundance of essential pathways involved in DAB colonization, such as bacterial motility and biofilm formation, as well as biodegradable ability, such as benzoate degradation and nitrogen metabolism, were significantly enriched under stress condition. The findings improve the understanding of the complexity of duckweed microbiomes and facilitate the establishment of a stable microbiome used for co-cultivation with duckweeds for enhancement of biomass and phytoremediation under environmental stress.

RevDate: 2022-11-29

Wang R, Zhang Q, Ju M, et al (2022)

The Endophytic Fungi Diversity, Community Structure, and Ecological Function Prediction of Sophora alopecuroides in Ningxia, China.

Microorganisms, 10(11):.

Sophora alopecuroides L. has great medicinal and ecological value in northwestern China. The host and its microbiota are mutually symbiotic, collectively forming a holobiont, conferring beneficial effects to the plant. However, the analysis of diversity, mycobiota composition, and the ecological function of endophytic fungi in the holobiont of S. alopecuroides is relatively lacking. In this article, the fungal community profiling of roots, stems, leaves, and seeds of S. alopecuroides (at the fruit maturity stage) from Huamachi and Baofeng in Ningxia, China were investigated based on the ITS1 region, using high-throughput sequencing technology. As a result, a total of 751 operational taxonomic units (OTUs) were obtained and further classified into 9 phyla, 27 classes, 66 orders, 141 families, 245 genera, and 340 species. The roots had the highest fungal richness and diversity, while the stems had the highest evenness and pedigree diversity. There also was a significant difference in the richness of the endophytic fungal community between root and seed (p < 0.05). The organ was the main factor affecting the community structure of endophytic fungi in S. alopecuroides. The genera of unclassified Ascomycota, Tricholoma, Apiotrichum, Alternaria, and Aspergillus made up the vast majority of relative abundance, which were common in all four organs as well. The dominant and endemic genera and biomarkers of endophytic fungi in four organs of S. alopecuroides were different and exhibited organ specificity or tissue preference. The endophytic fungi of S. alopecuroides were mainly divided into 15 ecological function groups, among which saprotroph was absolutely dominant, followed by mixotrophic and pathotroph, and the symbiotroph was the least. With this study, we revealed the diversity and community structure and predicted the ecological function of the endophytic fungi of S. alopecuroides, which provided a theoretical reference for the further development and utilization of the endophytic fungi resources of S. alopecuroides.

RevDate: 2022-11-17
CmpDate: 2022-11-14

Kiruba N JM, A Saeid (2022)

An Insight into Microbial Inoculants for Bioconversion of Waste Biomass into Sustainable "Bio-Organic" Fertilizers: A Bibliometric Analysis and Systematic Literature Review.

International journal of molecular sciences, 23(21):.

The plant-microbe holobiont has garnered considerable attention in recent years, highlighting its importance as an ecological unit. Similarly, manipulation of the microbial entities involved in the rhizospheric microbiome for sustainable agriculture has also been in the limelight, generating several commercial bioformulations to enhance crop yield and pest resistance. These bioformulations were termed biofertilizers, with the consistent existence and evolution of different types. However, an emerging area of interest has recently focused on the application of these microorganisms for waste valorization and the production of "bio-organic" fertilizers as a result. In this study, we performed a bibliometric analysis and systematic review of the literature retrieved from Scopus and Web of Science to determine the type of microbial inoculants used for the bioconversion of waste into "bio-organic" fertilizers. The Bacillus, Acidothiobacillus species, cyanobacterial biomass species, Aspergillus sp. and Trichoderma sp. were identified to be consistently used for the recovery of nutrients and bioconversion of wastes used for the promotion of plant growth. Cyanobacterial strains were used predominantly for wastewater treatment, while Bacillus, Acidothiobacillus, and Aspergillus were used on a wide variety of wastes such as sawdust, agricultural waste, poultry bone meal, crustacean shell waste, food waste, and wastewater treatment plant (WWTP) sewage sludge ash. Several bioconversion strategies were observed such as submerged fermentation, solid-state fermentation, aerobic composting, granulation with microbiological activation, and biodegradation. Diverse groups of microorganisms (bacteria and fungi) with different enzymatic functionalities such as chitinolysis, lignocellulolytic, and proteolysis, in addition to their plant growth promoting properties being explored as a consortium for application as an inoculum waste bioconversion to fertilizers. Combining the efficiency of such functional and compatible microbial species for efficient bioconversion as well as higher plant growth and crop yield is an enticing opportunity for "bio-organic" fertilizer research.

RevDate: 2022-11-17
CmpDate: 2022-11-14

Graindorge S, Villette C, Koechler S, et al (2022)

The Arabidopsis thaliana-Streptomyces Interaction Is Controlled by the Metabolic Status of the Holobiont.

International journal of molecular sciences, 23(21):.

How specific interactions between plant and pathogenic, commensal, or mutualistic microorganisms are mediated and how bacteria are selected by a plant are important questions to address. Here, an Arabidopsis thaliana mutant called chs5 partially deficient in the biogenesis of isoprenoid precursors was shown to extend its metabolic remodeling to phenylpropanoids and lipids in addition to carotenoids, chlorophylls, and terpenoids. Such a metabolic profile was concomitant to increased colonization of the phyllosphere by the pathogenic strain Pseudomonas syringae pv. tomato DC3000. A thorough microbiome analysis by 16S sequencing revealed that Streptomyces had a reduced colonization potential in chs5. This study revealed that the bacteria-Arabidopsis interaction implies molecular processes impaired in the chs5 mutant. Interestingly, our results revealed that the metabolic status of A. thaliana was crucial for the specific recruitment of Streptomyces into the microbiota. More generally, this study highlights specific as well as complex molecular interactions that shape the plant microbiota.

RevDate: 2022-11-17
CmpDate: 2022-11-14

Friedman Y (2022)

Who is the biological patient? A new gradational and dynamic model for one health medicine.

History and philosophy of the life sciences, 44(4):61.

One Health medicine aims to improve health by focusing on the relations between the health of humans, animals, and the environment. However, One Health does not provide a clear idea of these relations, which are still represented as conceptually separated and not as one health, as the name implies. Inspired by holobiont research, I suggest a new model and conceptual framework for One Health that expands the notion of the biological patient by providing a gradational and dynamic understanding of environments, patients, and their relations. This new model conceptualizes humans and non-humans, individual organisms, and collectives, as belonging to one system that allows for more or less inclusive understandings of patients. As such, it resolves the conceptual tensions of different One Health approaches and supports the implementation of One Health as an interdisciplinary research field.

RevDate: 2022-11-29
CmpDate: 2022-11-14

Castaldi A, Teta R, Esposito G, et al (2022)

Computational Metabolomics Tools Reveal Subarmigerides, Unprecedented Linear Peptides from the Marine Sponge Holobiont Callyspongia subarmigera.

Marine drugs, 20(11):.

A detailed examination of a unique molecular family, restricted to the Callyspongia genus, in a molecular network obtained from an in-house Haplosclerida marine sponge collection (including Haliclona, Callyspongia, Xestospongia, and Petrosia species) led to the discovery of subarmigerides, a series of rare linear peptides from Callyspongia subarmigera, a genus mainly known for polyacetylenes and lipids. The structure of the sole isolated peptide, subarmigeride A (1) was elucidated through extensive 1D and 2D NMR spectroscopy, HRMS/MS, and Marfey's method to assign its absolute configuration. The putative structures of seven additional linear peptides were proposed by an analysis of their respective MS/MS spectra and a comparison of their fragmentation patterns with the heptapeptide 1. Surprisingly, several structurally related analogues of subarmigeride A (1) occurred in one distinct cluster from the molecular network of the cyanobacteria strains of the Guadeloupe mangroves, suggesting that the true producer of this peptide family might be the microbial sponge-associated community, i.e., the sponge-associated cyanobacteria.

RevDate: 2022-11-19
CmpDate: 2022-11-18

Rasmussen N (2022)

René Dubos, the Autochthonous Flora, and the Discovery of the Microbiome.

Journal of the history of biology, 55(3):537-558.

Now characterised by high-throughput sequencing methods that enable the study of microbes without lab culture, the human "microbiome" (the microbial flora of the body) is said to have revolutionary implications for biology and medicine. According to many experts, we must now understand ourselves as "holobionts" like lichen or coral, multispecies superorganisms that consist of animal and symbiotic microbes in combination, because normal physiological function depends on them. Here I explore the 1960s research of biologist René Dubos, a forerunner figure mentioned in some historical accounts of the microbiome, and argue that he arrived at the superorganism concept 40 years before the Human Microbiome Project. This raises the question of why his contribution was not hailed as revolutionary at the time and why Dubos is not remembered for it.

RevDate: 2022-11-07

Cegarra L, Aguirre P, Nuñez MT, et al (2022)

Calcium is a non-competitive inhibitor of DMT1 on the intestinal iron absorption process: empirical evidence and mathematical modeling analysis.

American journal of physiology. Cell physiology [Epub ahead of print].

Iron absorption is a complex and highly controlled process where DMT1 transports nonheme iron through the brush border membrane of enterocytes to the cytoplasm but does not transport alkaline-earth metals such as calcium. However, it has been proposed that high concentrations of calcium from the diet could reduce iron bioavailability. In this work we investigate the effect of intracellular and extracellular calcium on iron uptake by Caco-2 cells, as determined by calcein fluorescence quenching. We found that extracellular calcium inhibits iron uptake by Caco-2 cells in a concentration-dependent manner. Chelation of intracellular calcium with BAPTA did not affect iron uptake, which indicates that the inhibitory effect of calcium is not exerted through intracellular calcium signaling. Kinetic studies performed, provided evidence that calcium acts as a reversible non-competitive inhibitor of the iron transport activity of DMT1. Based on these experimental results, a mathematical model was developed that considers the dynamics of non-competitive inhibition using a four-state mechanism to describe the inhibitory effect of calcium on the DMT1 iron transport process in intestinal cells. The model accurately predicts the calcein fluorescence quenching dynamics observed experimentally after an iron challenge. Therefore, the proposed model structure is capable of representing the inhibitory effect of extracellular calcium on DMT1-mediated iron entry into the cLIP of Caco-2 cells. Considering the range of calcium concentrations that can inhibit iron uptake, the possible inhibition of dietary calcium on intestinal iron uptake is discussed.

RevDate: 2022-11-08
CmpDate: 2022-11-08

Aubé J, Cambon-Bonavita MA, Velo-Suárez L, et al (2022)

A novel and dual digestive symbiosis scales up the nutrition and immune system of the holobiont Rimicaris exoculata.

Microbiome, 10(1):189.

BACKGROUND: In deep-sea hydrothermal vent areas, deprived of light, most animals rely on chemosynthetic symbionts for their nutrition. These symbionts may be located on their cuticle, inside modified organs, or in specialized cells. Nonetheless, many of these animals have an open and functional digestive tract. The vent shrimp Rimicaris exoculata is fueled mainly by its gill chamber symbionts, but also has a complete digestive system with symbionts. These are found in the shrimp foregut and midgut, but their roles remain unknown. We used genome-resolved metagenomics on separate foregut and midgut samples, taken from specimens living at three contrasted sites along the Mid-Atlantic Ridge (TAG, Rainbow, and Snake Pit) to reveal their genetic potential.

RESULTS: We reconstructed and studied 20 Metagenome-Assembled Genomes (MAGs), including novel lineages of Hepatoplasmataceae and Deferribacteres, abundant in the shrimp foregut and midgut, respectively. Although the former showed streamlined reduced genomes capable of using mostly broken-down complex molecules, Deferribacteres showed the ability to degrade complex polymers, synthesize vitamins, and encode numerous flagellar and chemotaxis genes for host-symbiont sensing. Both symbionts harbor a diverse set of immune system genes favoring holobiont defense. In addition, Deferribacteres were observed to particularly colonize the bacteria-free ectoperitrophic space, in direct contact with the host, elongating but not dividing despite possessing the complete genetic machinery necessary for this.

CONCLUSION: Overall, these data suggest that these digestive symbionts have key communication and defense roles, which contribute to the overall fitness of the Rimicaris holobiont. Video Abstract.

RevDate: 2022-11-07
CmpDate: 2022-11-07

Shao Q, Dong C, Hu H, et al (2022)

Effects of Medicinal Plants on Fungal Community Structure and Function in Hospital Grassplot Soil.

Current microbiology, 79(12):377.

Hospital grassplot soil is an important repository of pathogenic fungi exposed to the hospital environment, and the diffusion of these fungi-containing soil particles in the air increases the risk of nosocomial fungal infections. In this study, from the perspective of soil microbes-plant holobiont, four medicinal plants Mirabilis jalapa, Artemisia argyi, Viola philippica, and Plantago depressa were used as materials, based on ITS high-throughput amplicon sequencing and simulated pot experiments to explore the effect of medicinal plants on the fungal community in hospital grassplot soil, in order to provide a new exploration for hospital grassplot soil remediation. The results showed that the fungal community ecological guilds in primary test soil was mainly pathogen, and the abundance of animal pathogen with potential threats to human reached 61.36%. After planting medicinal plants, the composition and function of soil fungal community changed significantly. Although this change varied with plant species and growth stages, all samples collected in the pot experiment showed that the pathogen abundance decreased and the saprotroph abundance increased. In addition, 45 of the 46 core fungal genera defined in all potted samples were present in primary test soil, and many of them were human potential pathogens. These findings imply that the idea of enhancing soil quality in hospital grassplot soil by planting specific plants is feasible. However, the initial fungal community of the hospital grassplot soil has a certain stability, and it is difficult to completely eliminate the threat of pathogenic fungi by planting medicinal plants.

RevDate: 2022-11-23

KleinJan H, Frioux C, Califano G, et al (2022)

Insights into the potential for mutualistic and harmful host-microbe interactions affecting brown alga freshwater acclimation.

Molecular ecology [Epub ahead of print].

Microbes can modify their hosts' stress tolerance, thus potentially enhancing their ecological range. An example of such interactions is Ectocarpus subulatus, one of the few freshwater-tolerant brown algae. This tolerance is partially due to its (un)cultivated microbiome. We investigated this phenomenon by modifying the microbiome of laboratory-grown E. subulatus using mild antibiotic treatments, which affected its ability to grow in low salinity. Low salinity acclimation of these algal-bacterial associations was then compared. Salinity significantly impacted bacterial and viral gene expression, albeit in different ways across algal-bacterial communities. In contrast, gene expression of the host and metabolite profiles were affected almost exclusively in the freshwater-intolerant algal-bacterial communities. We found no evidence of bacterial protein production that would directly improve algal stress tolerance. However, vitamin K synthesis is one possible bacterial service missing specifically in freshwater-intolerant cultures in low salinity. In this condition, we also observed a relative increase in bacterial transcriptomic activity and the induction of microbial genes involved in the biosynthesis of the autoinducer AI-1, a quorum-sensing regulator. This could have resulted in dysbiosis by causing a shift in bacterial behaviour in the intolerant algal-bacterial community. Together, these results provide two promising hypotheses to be examined by future targeted experiments. Although they apply only to the specific study system, they offer an example of how bacteria may impact their host's stress response.

RevDate: 2022-11-02

Hempel E, Bibi F, Faith JT, et al (2022)

Blue turns to grey - Palaeogenomic insights into the evolutionary history and extinction of the blue antelope (Hippotragus leucophaeus).

Molecular biology and evolution pii:6794086 [Epub ahead of print].

The blue antelope (Hippotragus leucophaeus) is the only large African mammal species to have become extinct in historical times, yet no nuclear genomic information is available for this species. A recent study showed that many alleged blue antelope museum specimens are either roan (H. equinus) or sable (H. niger) antelopes, further reducing the possibilities for obtaining genomic information for this extinct species. While the blue antelope has a rich fossil record from South Africa, climatic conditions in the region are generally unfavourable to the preservation of ancient DNA. Nevertheless, we recovered two blue antelope draft genomes, one at 3.4x mean coverage from a historical specimen (∼200 years old) and one at 2.1x mean coverage from a fossil specimen dating to 9,800-9,300 cal years BP, making it currently the oldest palaeogenome from Africa. Phylogenomic analyses show that blue and sable antelope are sister species, confirming previous mitogenomic results, and demonstrate ancient gene flow from roan into blue antelope. We show that blue antelope genomic diversity was much lower than in roan and sable antelopes, indicative of a low population size since at least the early Holocene. This supports observations from the fossil record documenting major decreases in the abundance of blue antelope after the Pleistocene-Holocene transition. Finally, the persistence of this species throughout the Holocene despite low population size suggests that colonial-era human impact was likely a decisive factor in the blue antelope's extinction.

RevDate: 2022-11-05
CmpDate: 2022-11-03

Moffat JJ, Coffroth MA, Wallingford PD, et al (2022)

Symbiont genotype influences holobiont response to increased temperature.

Scientific reports, 12(1):18394.

As coral reefs face warming oceans and increased coral bleaching, a whitening of the coral due to loss of microalgal endosymbionts, the possibility of evolutionary rescue offers some hope for reef persistence. In tightly linked mutualisms, evolutionary rescue may occur through evolution of the host and/or endosymbionts. Many obligate mutualisms are composed of relatively small, fast-growing symbionts with greater potential to evolve on ecologically relevant time scales than their relatively large, slower growing hosts. Numerous jellyfish species harbor closely related endosymbiont taxa to other cnidarian species such as coral, and are commonly used as a model system for investigating cnidarian mutualisms. We examined the potential for adaptation of the upside-down jellyfish Cassiopea xamachana to increased temperature via evolution of its microalgal endosymbiont, Symbiodinium microadriaticum. We quantified trait variation among five algal genotypes in response to three temperatures (26 °C, 30 °C, and 32 °C) and fitness of hosts infected with each genotype. All genotypes showed positive growth rates at each temperature, but rates of respiration and photosynthesis decreased with increased temperature. Responses varied among genotypes but were unrelated to genetic similarity. The effect of temperature on asexual reproduction and the timing of development in the host also depended on the genotype of the symbiont. Natural selection could favor different algal genotypes at different temperatures, affecting host fitness. This eco-evolutionary interaction may be a critical component of understanding species resilience in increasingly stressful environments.

RevDate: 2022-10-31

Shantz AA, Ladd MC, Ezzat L, et al (2022)

Positive interactions between corals and damselfish increase coral resistance to temperature stress.

Global change biology [Epub ahead of print].

By the century's end, many tropical seas will reach temperatures exceeding most coral species' thermal tolerance on an annual basis. The persistence of corals in these regions will, therefore, depend on their abilities to tolerate recurrent thermal stress. Although ecologists have long recognized that positive interspecific interactions can ameliorate environmental stress to expand the realized niche of plants and animals, coral bleaching studies have largely overlooked how interactions with community members outside of the coral holobiont shape the bleaching response. Here, we subjected a common coral, Pocillopora grandis, to 10 days of thermal stress in aquaria with and without the damselfish Dascyllus flavicaudus (yellowtail dascyllus), which commonly shelter within these corals, to examine how interactions with damselfish impacted coral thermal tolerance. Corals often benefit from nutrients excreted by animals they interact with and prior to thermal stress, corals grown with damselfish showed improved photophysiology (Fv /Fm) and developed larger endosymbiont populations. When exposed to thermal stress, corals with fish performed as well as control corals maintained at ambient temperatures without fish. In contrast, corals exposed to thermal stress without fish experienced photophysiological impairment, a more than 50% decline in endosymbiont density, and a 36% decrease in tissue protein content. At the end of the experiment, thermal stress caused average calcification rates to decrease by over 80% when damselfish were absent but increase nearly 25% when damselfish were present. Our study indicates that damselfish-derived nutrients can increase coral thermal tolerance and are consistent with the Stress Gradient Hypothesis, which predicts that positive interactions become increasingly important for structuring communities as environmental stress increases. Because warming of just a few degrees can exceed corals' temperature tolerance to trigger bleaching and mortality, positive interactions could play a critical role in maintaining some coral species in warming regions until climate change is aggressively addressed.

RevDate: 2022-11-04
CmpDate: 2022-11-01

Koziol A, Odriozola I, Nyholm L, et al (2022)

Enriching captivity conditions with natural elements does not prevent the loss of wild-like gut microbiota but shapes its compositional variation in two small mammals.

MicrobiologyOpen, 11(5):e1318.

As continued growth in gut microbiota studies in captive and model animals elucidates the importance of their role in host biology, further pursuit of how to retain a wild-like microbial community is becoming increasingly important to obtain representative results from captive animals. In this study, we assessed how the gut microbiota of two wild-caught small mammals, namely Crocidura russula (Eulipotyphla, insectivore) and Apodemus sylvaticus (Rodentia, omnivore), changed when bringing them into captivity. We analyzed fecal samples of 15 A. sylvaticus and 21 C. russula, immediately after bringing them into captivity and 5 weeks later, spread over two housing treatments: a "natural" setup enriched with elements freshly collected from nature and a "laboratory" setup with sterile artificial elements. Through sequencing of the V3-V4 region of the 16S recombinant RNA gene, we found that the initial microbial diversity dropped during captivity in both species, regardless of treatment. Community composition underwent a change of similar magnitude in both species and under both treatments. However, we did observe that the temporal development of the gut microbiome took different trajectories (i.e., changed in different directions) under different treatments, particularly in C. russula, suggesting that C. russula may be more susceptible to environmental change. The results of this experiment do not support the use of microbially enriched environments to retain wild-like microbial diversities and compositions, yet show that specific housing conditions can significantly affect the drift of microbial communities under captivity.

RevDate: 2022-11-29

Snelders NC, Boshoven JC, Song Y, et al (2022)

A highly polymorphic effector protein promotes fungal virulence through suppression of plant-associated Actinobacteria.

The New phytologist [Epub ahead of print].

Plant pathogens secrete effector proteins to support host colonization through a wide range of molecular mechanisms, while plant immune systems evolved receptors to recognize effectors or their activities to mount immune responses to halt pathogens. Importantly, plants do not act as single organisms, but rather as holobionts that actively shape their microbiota as a determinant of health. The soil-borne fungal pathogen Verticillium dahliae was recently demonstrated to exploit the VdAve1 effector to manipulate the host microbiota to promote vascular wilt disease in the absence of the corresponding immune receptor Ve1. We identify a multiallelic V. dahliae gene displaying c. 65% sequence similarity to VdAve1, named VdAve1-like (VdAve1L), which shows extreme sequence variation, including alleles that encode dysfunctional proteins, indicative of selection pressure to overcome host recognition. We show that the orphan cell surface receptor Ve2, encoded at the Ve locus, does not recognize VdAve1L. Additionally, we demonstrate that the full-length variant VdAve1L2 possesses antimicrobial activity, like VdAve1, yet with a divergent activity spectrum, that is exploited by V. dahliae to mediate tomato colonization through the direct suppression of antagonistic Actinobacteria in the host microbiota. Our findings open up strategies for more targeted biocontrol against microbial plant pathogens.

RevDate: 2022-11-04
CmpDate: 2022-10-28

Olesen AS, Kodama M, Skovgaard K, et al (2022)

Influence of African Swine Fever Virus on Host Gene Transcription within Peripheral Blood Mononuclear Cells from Infected Pigs.

Viruses, 14(10):.

African swine fever virus (ASFV) has become a global threat to the pig production industry and has caused enormous economic losses in many countries in recent years. Peripheral blood mononuclear cells (PBMCs) from pigs infected with ASFV not only express ASFV genes (almost 200 in number) but have altered patterns of host gene expression as well. Both up- and down-regulation of host cell gene expression can be followed using RNAseq on poly(A)+ mRNAs harvested from the PBMCs of pigs collected at different times post-infection. Consistent with the time course of changes in viral gene expression, only few and limited changes in host gene expression were detected at 3 days post-infection (dpi), but by 6 dpi, marked changes in the expression of over 1300 host genes were apparent. This was co-incident with the major increase in viral gene expression. The majority of the changes in host gene expression were up-regulation, but many down-regulated genes were also identified. The patterns of changes in gene expression within the PBMCs detected by RNAseq were similar in each of the four infected pigs. Furthermore, changes in the expression of about twenty selected host genes, known to be important in host defence and inflammatory responses, were confirmed using high-throughput microfluidic qPCR assays.

RevDate: 2022-10-30

Carper DL, Appidi MR, Mudbhari S, et al (2022)

The Promises, Challenges, and Opportunities of Omics for Studying the Plant Holobiont.

Microorganisms, 10(10):.

Microorganisms are critical drivers of biological processes that contribute significantly to plant sustainability and productivity. In recent years, emerging research on plant holobiont theory and microbial invasion ecology has radically transformed how we study plant-microbe interactions. Over the last few years, we have witnessed an accelerating pace of advancements and breadth of questions answered using omic technologies. Herein, we discuss how current state-of-the-art genomics, transcriptomics, proteomics, and metabolomics techniques reliably transcend the task of studying plant-microbe interactions while acknowledging existing limitations impeding our understanding of plant holobionts.

RevDate: 2022-10-30
CmpDate: 2022-10-28

Lim DW, JH Wang (2022)

Gut Microbiome: The Interplay of an "Invisible Organ" with Herbal Medicine and Its Derived Compounds in Chronic Metabolic Disorders.

International journal of environmental research and public health, 19(20):.

Resembling a concealed "organ" in a holobiont, trillions of gut microbes play complex roles in the maintenance of homeostasis, including participating in drug metabolism. The conventional opinion is that most of any drug is metabolized by the host and that individual differences are principally due to host genetic factors. However, current evidence indicates that only about 60% of the individual differences in drug metabolism are attributable to host genetics. Although most common chemical drugs regulate the gut microbiota, the gut microbiota is also known to be involved in drug metabolism, like the host. Interestingly, many traditional herbal medicines and derived compounds are biotransformed by gut microbiota, manipulating the compounds' effects. Accordingly, the gut microbiota and its specified metabolic pathways can be deemed a promising target for promoting drug efficacy and safety. However, the evidence regarding causality and the corresponding mechanisms concerning gut microbiota and drug metabolism remains insufficient, especially regarding drugs used to treat metabolic disorders. Therefore, the present review aims to comprehensively summarize the bidirectional roles of gut microbiota in the effects of herbal medicine in metabolic diseases to provide vital clues for guiding the clinical application of precision medicine and personalized drug development.

RevDate: 2022-10-26

Puntin G, Sweet M, Fraune S, et al (2022)

Harnessing the Power of Model Organisms To Unravel Microbial Functions in the Coral Holobiont.

Microbiology and molecular biology reviews : MMBR [Epub ahead of print].

Stony corals build the framework of coral reefs, ecosystems of immense ecological and economic importance. The existence of these ecosystems is threatened by climate change and other anthropogenic stressors that manifest in microbial dysbiosis such as coral bleaching and disease, often leading to coral mortality. Despite a significant amount of research, the mechanisms ultimately underlying these destructive phenomena, and what could prevent or mitigate them, remain to be resolved. This is mostly due to practical challenges in experimentation on corals and the highly complex nature of the coral holobiont that also includes bacteria, archaea, protists, and viruses. While the overall importance of these partners is well recognized, their specific contributions to holobiont functioning and their interspecific dynamics remain largely unexplored. Here, we review the potential of adopting model organisms as more tractable systems to address these knowledge gaps. We draw on parallels from the broader biological and biomedical fields to guide the establishment, implementation, and integration of new and emerging model organisms with the aim of addressing the specific needs of coral research. We evaluate the cnidarian models Hydra, Aiptasia, Cassiopea, and Astrangia poculata; review the fast-evolving field of coral tissue and cell cultures; and propose a framework for the establishment of "true" tropical reef-building coral models. Based on this assessment, we also suggest future research to address key aspects limiting our ability to understand and hence improve the response of reef-building corals to future ocean conditions.

RevDate: 2022-11-25
CmpDate: 2022-11-25

Foucault P, Gallet A, Duval C, et al (2022)

Gut microbiota and holobiont metabolome composition of the medaka fish (Oryzias latipes) are affected by a short exposure to the cyanobacterium Microcystis aeruginosa.

Aquatic toxicology (Amsterdam, Netherlands), 253:106329.

Blooms of toxic cyanobacteria are a common stress encountered by aquatic fauna. Evidence indicates that long-lasting blooms affect fauna-associated microbiota. Because of their multiple roles, host-associated microbes are nowadays considered relevant to ecotoxicology, yet the respective timing of microbiota versus functional changes in holobionts response needs to be clarified. The response of gut microbiota and holobiont's metabolome to exposure to a dense culture of Microcystis aeruginosa was investigated as a microcosm-simulated bloom in the model fish species Oryzias latipes (medaka). Both gut microbiota and gut metabolome displayed significant composition changes after only 2 days of exposure. A dominant symbiont, member of the Firmicutes, plummeted whereas various genera of Proteobacteria and Actinobacteriota increased in relative abundance. Changes in microbiota composition occurred earlier and faster compared to metabolome composition. Liver and muscle metabolome were much less affected than guts, supporting that the gut and associated microbiota are in the front row upon exposure. This study highlights that even short cyanobacterial blooms, that are increasingly frequent, trigger changes in microbiota composition and holobiont metabolome. It emphasizes the relevance of multi-omics approaches to explore organism's response to an ecotoxicological stress.

RevDate: 2022-10-22
CmpDate: 2022-10-21

Siddique S, Radakovic ZS, Hiltl C, et al (2022)

The genome and lifestage-specific transcriptomes of a plant-parasitic nematode and its host reveal susceptibility genes involved in trans-kingdom synthesis of vitamin B5.

Nature communications, 13(1):6190.

Plant-parasitic nematodes are a major threat to crop production in all agricultural systems. The scarcity of classical resistance genes highlights a pressing need to find new ways to develop nematode-resistant germplasm. Here, we sequence and assemble a high-quality phased genome of the model cyst nematode Heterodera schachtii to provide a platform for the first system-wide dual analysis of host and parasite gene expression over time, covering all major parasitism stages. Analysis of the hologenome of the plant-nematode infection site identified metabolic pathways that were incomplete in the parasite but complemented by the host. Using a combination of bioinformatic, genetic, and biochemical approaches, we show that a highly atypical completion of vitamin B5 biosynthesis by the parasitic animal, putatively enabled by a horizontal gene transfer from a bacterium, is required for full pathogenicity. Knockout of either plant-encoded or now nematode-encoded steps in the pathway significantly reduces parasitic success. Our experiments establish a reference for cyst nematodes, further our understanding of the evolution of plant-parasitism by nematodes, and show that congruent differential expression of metabolic pathways in the infection hologenome represents a new way to find nematode susceptibility genes. The approach identifies genome-editing-amenable targets for future development of nematode-resistant crops.

RevDate: 2022-10-31

Jonas L, R Hill (2022)

Uptake of inorganic and organic phosphorus compounds by two marine sponges and their associated bacterial communities in aquaria.

Environmental microbiology [Epub ahead of print].

Marine sponges are abundant filter-feeders in benthic ecosystems and many host copious microorganisms. Sponges and their symbionts have emerged as major players within marine biogeochemical cycles, facilitating uptake and release of carbon, nitrogen, and sulfur. Sponge holobionts' role in transforming dissolved carbon and nitrogen is well established; however, the same depth of understanding has not yet been extended to phosphorus. In this aquaria-based study, [32] P-labelled orthophosphate and ATP were used to determine that two sponges, Lendenfeldia chondrodes and Hymeniacidon heliophila, both take up ambient dissolved inorganic phosphate (DIP) and dissolved organic phosphorus (DOP). Subsequent genetic analyses and chemical extraction showed that sponge symbionts have the potential to synthesise polyphosphate (poly-P) and that this energy-rich form of stored phosphorus is present in both sponges. L. chondrodes, an oligotrophic sponge with a microbiome dominated by cyanobacteria, stores more phosphorus as poly-P (6%-8% of total phosphorus) than H. heliophila (0.55%), a eutrophic sponge with low cyanobacterial abundance. DIP/DOP uptake, as well as poly-P storage, may be driven by two factors: cyanobacterial abundance and nutrient availability. Considering their prevalence in phosphorus-limited ecosystems and their ability to pump large amounts of seawater, sponge holobionts are likely to be key players within benthic phosphorus cycles.

RevDate: 2022-11-08

Schmittmann L, Rahn T, Busch K, et al (2022)

Stability of a dominant sponge-symbiont in spite of antibiotic-induced microbiome disturbance.

Environmental microbiology [Epub ahead of print].

Marine sponges are known for their complex and stable microbiomes. However, the lack of a gnotobiotic sponge-model and experimental methods to manipulate both the host and the microbial symbionts currently limit our mechanistic understanding of sponge-microbial symbioses. We have used the North Atlantic sponge species Halichondria panicea to evaluate the use of antibiotics to generate gnotobiotic sponges. We further asked whether the microbiome can be reestablished via recolonization with the natural microbiome. Experiments were performed in marine gnotobiotic facilities equipped with a custom-made, sterile, flow-through aquarium system. Bacterial abundance dynamics were monitored qualitatively and quantitatively by 16 S rRNA gene amplicon sequencing and qPCR, respectively. Antibiotics induced dysbiosis by favouring an increase of opportunistic, antibiotic-resistant bacteria, resulting in more complex, but less specific bacteria-bacteria interactions than in untreated sponges. The abundance of the dominant symbiont, Candidatus Halichondribacter symbioticus, remained overall unchanged, reflecting its obligately symbiotic nature. Recolonization with the natural microbiome could not reverse antibiotic-induced dysbiosis. However, single bacterial taxa that were transferred, successfully recolonized the sponge and affected bacteria-bacteria interactions. By experimentally manipulating microbiome composition, we could show the stability of a sponge-symbiont clade despite microbiome dysbiosis. This study contributes to understanding both host-bacteria and bacteria-bacteria interactions in the sponge holobiont.

RevDate: 2022-10-19

Iglesias-Carrasco M, Tobias JA, DA Duchêne (2022)

Bird lineages colonizing urban habitats have diversified at high rates across deep time.

Global ecology and biogeography : a journal of macroecology, 31(9):1784-1793.

AIM: Urbanization exposes species to novel ecological conditions. Some species thrive in urban areas, whereas many others are excluded from these human-made environments. Previous analyses suggest that the ability to cope with rapid environmental change is associated with long-term patterns of diversification, but whether the suite of traits associated with the ability to colonize urban environments is linked to this process remains poorly understood.



MAJOR TAXA STUDIED: Passerine birds.

METHODS: We applied macroevolutionary models to a large dataset of passerine birds to compare the evolutionary history of urban-tolerant species with that of urban-avoidant species. Specifically, we examined models of state-dependent speciation and extinction to assess the macroevolution of urban tolerance as a binary trait, in addition to models of quantitative trait-dependent diversification based on relative urban abundance. We also ran simulation-based model assessments to explore potential sources of bias.

RESULTS: We provide evidence that historically, species with traits promoting urban colonization have undergone faster diversification than urban-avoidant species, indicating that urbanization favours clades with a historical tendency towards rapid speciation or reduced extinction. In addition, we find that past transitions towards states that currently impede urban colonization by passerines have been more frequent than in the opposite direction. Furthermore, we find a portion of urban-avoidant passerines to be recent and to undergo fast diversification. All highly supported models give this result consistently.

MAIN CONCLUSIONS: Urbanization is mainly associated with the loss of lineages that are inherently more vulnerable to extinction over deep time, whereas cities tend to be colonized by less vulnerable lineages, for which urbanization might be neutral or positive in terms of longer-term diversification. Urban avoidance is associated with high rates of recent diversification for some clades occurring in regions with relatively intact natural ecosystems and low current levels of urbanization.

RevDate: 2022-10-19
CmpDate: 2022-10-17

Han T, Liao X, Zhu Y, et al (2022)

Full-Length Transcriptome Maps of Reef-Building Coral Illuminate the Molecular Basis of Calcification, Symbiosis, and Circadian Genes.

International journal of molecular sciences, 23(19):.

Coral transcriptomic data largely rely on short-read sequencing, which severely limits the understanding of coral molecular mechanisms and leaves many important biological questions unresolved. Here, we sequence the full-length transcriptomes of four common and frequently dominant reef-building corals using the PacBio Sequel II platform. We obtain information on reported gene functions, structures, and expression profiles. Among them, a comparative analysis of biomineralization-related genes provides insights into the molecular basis of coral skeletal density. The gene expression profiles of the symbiont Symbiodiniaceae are also isolated and annotated from the holobiont sequence data. Finally, a phylogenetic analysis of key circadian clock genes among 40 evolutionarily representative species indicates that there are four key members in early metazoans, including cry genes; Clock or Npas2; cyc or Arntl; and tim, while per, as the fifth member, occurs in Bilateria. In summary, this work provides a foundation for further work on the manipulation of skeleton production or symbiosis to promote the survival of these important organisms.

RevDate: 2022-12-04
CmpDate: 2022-10-17

Ali H, Pei M, Li H, et al (2022)

The Wheat Head Blight Pathogen Fusarium graminearum Can Recruit Collaborating Bacteria from Soil.

Cells, 11(19):.

In nature, fungal endophytes often have facultative endohyphal bacteria (FEB). Can a model plant pathogenic fungus have them, and does it affect their phenotype? We constructed a growth system/microcosm to allow an F. graminearum isolate to grow through natural soil and then re-isolated it on a gentamicin-containing medium, allowing endohyphal growth of bacteria while killing other bacteria. F. graminearum PH-1 labelled with a His1mCherry gene staining the fungal nuclei fluorescent red was used to confirm the re-isolation of the fungus. Most new re-isolates contained about 10 16SrRNA genes per fungal mCherry gene determined by qPCR. The F. graminearum + FEB holobiont isolates containing the bacteria were sub-cultured several times, and their bacterial contents were stable. Sequencing the bacterial 16SrRNA gene from several Fg-FEB holobiont isolates revealed endophytic bacteria known to be capable of nitrogen fixation. We tested the pathogenicity of one common Fg-FEB holobiont association, F. graminearum + Stenatrophomonas maltophilia, and found increased pathogenicity. The 16SrRNA gene load per fungal His1mCherry gene inside the wheat stayed the same as previously found in vitro. Finally, strong evidence was found for Fg-S. maltophilia symbiotic nitrogen fixation benefitting the fungus.

RevDate: 2022-10-18

Armengaud J (2022)

Metaproteomics to understand how microbiota function: The crystal ball predicts a promising future.

Environmental microbiology [Epub ahead of print].

In the medical, environmental, and biotechnological fields, microbial communities have attracted much attention due to their roles and numerous possible applications. The study of these communities is challenging due to their diversity and complexity. Innovative methods are needed to identify the taxonomic components of individual microbiota, their changes over time, and to determine how microoorganisms interact and function. Metaproteomics is based on the identification and quantification of proteins, and can potentially provide this full picture. Due to the wide molecular panorama and functional insights it provides, metaproteomics is gaining momentum in microbiome and holobiont research. Its full potential should be unleashed in the coming years with progress in speed and cost of analyses. In this exploratory crystal ball exercise, I discuss the technical and conceptual advances in metaproteomics that I expect to drive innovative research over the next few years in microbiology. I also debate the concepts of 'microbial dark matter' and 'Metaproteomics-Assembled Proteomes (MAPs)' and present some long-term prospects for metaproteomics in clinical diagnostics and personalized medicine, environmental monitoring, agriculture, and biotechnology.

RevDate: 2022-11-21

van Oppen MJH, JB Raina (2022)

Coral holobiont research needs spatial analyses at the microbial scale.

Environmental microbiology [Epub ahead of print].

RevDate: 2022-10-11

Marco S, Loredana M, Riccardo V, et al (2022)

Microbe-assisted crop improvement: a sustainable weapon to restore holobiont functionality and resilience.

Horticulture research, 9:uhac160.

In the past years, breeding programs have been mainly addressed on pushing the commercial features, forgetting important traits, such as those related to environmental stress resilience, that are instead present in wild relatives. Among the traits neglected by breeding processes, the ability to recruit beneficial microorganisms that recently is receiving a growing attention due to its potentiality. In this context, this review will provide a spotlight on critical issues of the anthropocentric point of view that, until now, has characterized the selection of elite plant genotypes. Its effects on the plant-microbiome interactions, and the possibility to develop novel strategies mediated by the exploitation of beneficial root-microbe interactions, will be discussed. More sustainable microbial-assisted strategies might in fact foster the green revolution and the achievement of a more sustainable agriculture in a climatic change scenario.

RevDate: 2022-12-01
CmpDate: 2022-12-01

Connor KL, Bloise E, DeSantis TZ, et al (2023)

Adaptation of the gut holobiont to malnutrition during mouse pregnancy depends on the type of nutritional adversity.

The Journal of nutritional biochemistry, 111:109172.

Malnutrition can influence maternal physiology and programme offspring development. Yet, in pregnancy, little is known about how dietary challenges that influence maternal phenotype affect gut structure and function. Emerging evidence suggests that interactions between the environment, multidrug resistance (MDR) transporters and microbes may influence maternal adaptation to pregnancy and regulate fetoplacental development. We hypothesized that the gut holobiont (host and microbes) during pregnancy adapts differently to suboptimal maternal diets, evidenced by changes in the gut microenvironment, morphology, and expression of key protective MDR transporters during pregnancy. Mice were fed a control diet (CON) during pregnancy, or undernourished (UN) by 30% of control intake from gestational day (GD) 5.5-18.5, or fed 60% high fat diet (HF) for 8 weeks before and during pregnancy. At GD18.5, maternal small intestinal (SI) architecture (H&E), proliferation (Ki67), P-glycoprotein (P-gp - encoded by Abcb1a/b) and breast cancer resistance protein (BCRP/Abcg2) MDR transporter expression and levels of pro-inflammatory biomarkers were assessed. Circulating inflammatory biomarkers and maternal caecal microbiome composition (G3 PhyloChip[TM]) were measured. MDR transporter expression was also assessed in fetal gut. HF diet increased maternal SI crypt depth and proinflammatory load, and decreased SI expression of Abcb1a mRNA, whilst UN increased SI villi proliferation and Abcb1a, but decreased Abcg2, mRNA expression. There were significant associations between Abcb1a and Abcg2 mRNA levels with relative abundance of specific microbial taxa. Using a systems physiology approach we report that common nutritional adversities provoke adaptations in the pregnancy holobiont in mice, and reveal new mechanisms that could influence reproductive outcomes and fetal development.

RevDate: 2022-11-23
CmpDate: 2022-11-23

Nalley EM, Tuttle LJ, Conklin EE, et al (2023)

A systematic review and meta-analysis of the direct effects of nutrients on corals.

The Science of the total environment, 856(Pt 1):159093.

Chronic exposure of coral reefs to elevated nutrient conditions can modify the performance of the coral holobiont and shift the competitive interactions of reef organisms. Many studies have now quantified the links between nutrients and coral performance, but few have translated these studies to directly address coastal water quality standards. To address this management need, we conducted a systematic review of peer-reviewed studies, public reports, and gray literature that examined the impacts of dissolved inorganic nitrogen (DIN: nitrate, nitrite, and ammonium) and dissolved inorganic phosphorus (DIP: phosphate) on scleractinian corals. The systematic review resulted in 47 studies with comparable data on coral holobiont responses to nutrients: symbiont density, chlorophyll a (chl-a) concentration, photosynthesis, photosynthetic efficiency, growth, calcification, adult survival, juvenile survival, and fertilization. Mixed-effects meta-regression meta-analyses were used to determine the magnitude of the positive or negative effects of DIN and DIP on coral responses. Zooxanthellae density (DIN & DIP), chl-a concentration (DIN), photosynthetic rate (DIN), and growth (DIP) all exhibited positive responses to nutrient addition; maximum quantum yield (DIP), growth (DIN), larval survival (DIN), and fertilization (DIN) exhibited negative responses. In lieu of developing specific thresholds for the management of nutrients as a stressor on coral reefs, we highlight important inflection points in the magnitude and direction of the effects of inorganic nutrients and identify trends among coral responses. The responses of corals to nutrients are complex, warranting conservative guidelines for elevated nutrient concentrations on coral reefs.

RevDate: 2022-10-03
CmpDate: 2022-10-03

Campana S, Riesgo A, Jongepier E, et al (2022)

Meta-transcriptomic comparison of two sponge holobionts feeding on coral- and macroalgal-dissolved organic matter.

BMC genomics, 23(1):674.

BACKGROUND: Sponge holobionts (i.e., the host and its associated microbiota) play a key role in the cycling of dissolved organic matter (DOM) in marine ecosystems. On coral reefs, an ecological shift from coral-dominated to algal-dominated ecosystems is currently occurring. Given that benthic corals and macroalgae release different types of DOM, in different abundances and with different bioavailability to sponge holobionts, it is important to understand how the metabolic activity of the host and associated microbiota change in response to the exposure to both DOM sources. Here, we look at the differential gene expression of two sponge holobionts 6 hours after feeding on naturally sourced coral- and macroalgal-DOM using RNA sequencing and meta-transcriptomic analysis.

RESULTS: We found a slight, but significant differential gene expression in the comparison between the coral- and macroalgal-DOM treatments in both the high microbial abundance sponge Plakortis angulospiculatus and the low microbial abundance sponge Haliclona vansoesti. In the hosts, processes that regulate immune response, signal transduction, and metabolic pathways related to cell proliferation were elicited. In the associated microbiota carbohydrate metabolism was upregulated in both treatments, but coral-DOM induced further lipid and amino acids biosynthesis, while macroalgal-DOM caused a stress response. These differences could be driven by the presence of distinct organic macronutrients in the two DOM sources and of small pathogens or bacterial virulence factors in the macroalgal-DOM.

CONCLUSIONS: This work provides two new sponge meta-transcriptomes and a database of putative genes and genetic pathways that are involved in the differential processing of coral- versus macroalgal-DOM as food source to sponges with high and low abundances of associated microbes. These pathways include carbohydrate metabolism, signaling pathways, and immune responses. However, the differences in the meta-transcriptomic responses of the sponge holobionts after 6 hours of feeding on the two DOM sources were small. Longer-term responses to both DOM sources should be assessed to evaluate how the metabolism and the ecological function of sponges will be affected when reefs shift from coral towards algal dominance.

RevDate: 2022-09-30

Wu D, Yang L, Gu J, et al (2022)

A Functional Genomics View of Gibberellin Metabolism in the Cnidarian Symbiont Breviolum minutum.

Frontiers in plant science, 13:927200.

Dinoflagellate inhabitants of the reef-building corals exchange nutrients and signals with host cells, which often benefit the growth of both partners. Phytohormones serve as central hubs for signal integration between symbiotic microbes and their hosts, allowing appropriate modulation of plant growth and defense in response to various stresses. However, the presence and function of phytohormones in photosynthetic dinoflagellates and their function in the holobionts remain elusive. We hypothesized that endosymbiotic dinoflagellates may produce and employ phytohormones for stress responses. Using the endosymbiont of reef corals Breviolum minutum as model, this study aims to exam whether the alga employ analogous signaling systems by an integrated multiomics approach. We show that key gibberellin (GA) biosynthetic genes are widely present in the genomes of the selected dinoflagellate algae. The non-13-hydroxylation pathway is the predominant route for GA biosynthesis and the multifunctional GA dioxygenase in B. minutum has distinct substrate preference from high plants. GA biosynthesis is modulated by the investigated bleaching-stimulating stresses at both transcriptional and metabolic levels and the exogenously applied GAs improve the thermal tolerance of the dinoflagellate. Our results demonstrate the innate ability of a selected Symbiodiniaceae to produce the important phytohormone and the active involvement of GAs in the coordination and the integration of the stress response.

RevDate: 2022-11-28
CmpDate: 2022-09-30

Sardar P, Šustr V, Chroňáková A, et al (2022)

De novo metatranscriptomic exploration of gene function in the millipede holobiont.

Scientific reports, 12(1):16173.

Invertebrate-microbial associations are widespread in the biosphere and are often related to the function of novel genes, fitness advantages, and even speciation events. Despite ~ 13,000 species of millipedes identified across the world, millipedes and their gut microbiota are markedly understudied compared to other arthropods. Exploring the contribution of individual host-associated microbes is often challenging as many are uncultivable. In this study, we conducted metatranscriptomic profiling of different body segments of a millipede at the holobiont level. This is the first reported transcriptome assembly of a tropical millipede Telodeinopus aoutii (Demange, 1971), as well as the first study on any Myriapoda holobiont. High-throughput RNA sequencing revealed that Telodeinopus aoutii contained > 90% of the core Arthropoda genes. Proteobacteria, Bacteroidetes, Firmicutes, and Euryarchaeota represented dominant and functionally active phyla in the millipede gut, among which 97% of Bacteroidetes and 98% of Firmicutes were present exclusively in the hindgut. A total of 37,831 predicted protein-coding genes of millipede holobiont belonged to six enzyme classes. Around 35% of these proteins were produced by microbiota in the hindgut and 21% by the host in the midgut. Our results indicated that although major metabolic pathways operate at the holobiont level, the involvement of some host and microbial genes are mutually exclusive and microbes predominantly contribute to essential amino acid biosynthesis, short-chain fatty acid metabolism, and fermentation.

RevDate: 2022-09-28

Verma NK, Tan SJ, Chen J, et al (2022)

inPhocus: Current State and Challenges of Phage Research in Singapore.

PHAGE (New Rochelle, N.Y.), 3(1):6-11.

Bacteriophages and phage-derived proteins are a promising class of antibacterial agents that experience a growing worldwide interest. To map ongoing phage research in Singapore and neighboring countries, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore (NTU) and Yong Loo Lin School of Medicine, National University of Singapore (NUS) recently co-organized a virtual symposium on Bacteriophage and Bacteriophage-Derived Technologies, which was attended by more than 80 participants. Topics were discussed relating to phage life cycles, diversity, the roles of phages in biofilms and the human gut microbiome, engineered phage lysins to combat polymicrobial infections in wounds, and the challenges and prospects of clinical phage therapy. This perspective summarizes major points discussed during the symposium and new perceptions that emerged after the panel discussion.

RevDate: 2022-09-28

Nie Y, Lau SYL, Tan X, et al (2022)

Sphagnum capillifolium holobiont from a subarctic palsa bog aggravates the potential of nitrous oxide emissions.

Frontiers in plant science, 13:974251.

Melting permafrost mounds in subarctic palsa mires are thawing under climate warming and have become a substantial source of N2O emissions. However, mechanistic insights into the permafrost thaw-induced N2O emissions in these unique habitats remain elusive. We demonstrated that N2O emission potential in palsa bogs was driven by the bacterial residents of two dominant Sphagnum mosses especially of Sphagnum capillifolium (SC) in the subarctic palsa bog, which responded to endogenous and exogenous Sphagnum factors such as secondary metabolites, nitrogen and carbon sources, temperature, and pH. SC's high N2O emission activity was linked with two classes of distinctive hyperactive N2O emitters, including Pseudomonas sp. and Enterobacteriaceae bacteria, whose hyperactive N2O emitting capability was characterized to be dominantly pH-responsive. As the nosZ gene-harboring emitter, Pseudomonas sp. SC-H2 reached a high level of N2O emissions that increased significantly with increasing pH. For emitters lacking the nosZ gene, an Enterobacteriaceae bacterium SC-L1 was more adaptive to natural acidic conditions, and N2O emissions also increased with pH. Our study revealed previously unknown hyperactive N2O emitters in Sphagnum capillifolium found in melting palsa mound environments, and provided novel insights into SC-associated N2O emissions.


RJR Experience and Expertise


Robbins holds BS, MS, and PhD degrees in the life sciences. He served as a tenured faculty member in the Zoology and Biological Science departments at Michigan State University. He is currently exploring the intersection between genomics, microbial ecology, and biodiversity — an area that promises to transform our understanding of the biosphere.


Robbins has extensive experience in college-level education: At MSU he taught introductory biology, genetics, and population genetics. At JHU, he was an instructor for a special course on biological database design. At FHCRC, he team-taught a graduate-level course on the history of genetics. At Bellevue College he taught medical informatics.


Robbins has been involved in science administration at both the federal and the institutional levels. At NSF he was a program officer for database activities in the life sciences, at DOE he was a program officer for information infrastructure in the human genome project. At the Fred Hutchinson Cancer Research Center, he served as a vice president for fifteen years.


Robbins has been involved with information technology since writing his first Fortran program as a college student. At NSF he was the first program officer for database activities in the life sciences. At JHU he held an appointment in the CS department and served as director of the informatics core for the Genome Data Base. At the FHCRC he was VP for Information Technology.


While still at Michigan State, Robbins started his first publishing venture, founding a small company that addressed the short-run publishing needs of instructors in very large undergraduate classes. For more than 20 years, Robbins has been operating The Electronic Scholarly Publishing Project, a web site dedicated to the digital publishing of critical works in science, especially classical genetics.


Robbins is well-known for his speaking abilities and is often called upon to provide keynote or plenary addresses at international meetings. For example, in July, 2012, he gave a well-received keynote address at the Global Biodiversity Informatics Congress, sponsored by GBIF and held in Copenhagen. The slides from that talk can be seen HERE.


Robbins is a skilled meeting facilitator. He prefers a participatory approach, with part of the meeting involving dynamic breakout groups, created by the participants in real time: (1) individuals propose breakout groups; (2) everyone signs up for one (or more) groups; (3) the groups with the most interested parties then meet, with reports from each group presented and discussed in a subsequent plenary session.


Robbins has been engaged with photography and design since the 1960s, when he worked for a professional photography laboratory. He now prefers digital photography and tools for their precision and reproducibility. He designed his first web site more than 20 years ago and he personally designed and implemented this web site. He engages in graphic design as a hobby.


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This book examines how the growing knowledge of the huge range of animal-bacterial interactions, whether in shared ecosystems or intimate symbioses, is fundamentally altering our understanding of animal biology. Individuals from simple invertebrates to human are not solitary, homogenous entities but consist of complex communities of many species that likely evolved during a billion years of coexistence. 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. The hologenome theory of evolution considers the holobiont with its hologenome as a unit of selection in evolution. This new view may have profound impact on understanding a strictly microbe/symbiont-dependent life style and its evolutionary consequences. It may also affect the way how we approach complex environmental diseases from corals (coral bleaching) to human (inflammatory bowel disease etc). The book is written for scientists as well as medically interested persons in the field of immunobiology, microbiology, evolutionary biology, evolutionary medicine and corals. R. Robbins

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Collection of publications by R J Robbins

Reprints and preprints of publications, slide presentations, instructional materials, and data compilations written or prepared by Robert Robbins. Most papers deal with computational biology, genome informatics, using information technology to support biomedical research, and related matters.

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Curriculum Vitae for R J Robbins

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Curriculum Vitae for R J Robbins

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