About | BLOGS | Portfolio | Misc | Recommended | What's New | What's Hot

About | BLOGS | Portfolio | Misc | Recommended | What's New | What's Hot


Bibliography Options Menu

16 Dec 2018 at 01:41
Hide Abstracts   |   Hide Additional Links
Long bibliographies are displayed in blocks of 100 citations at a time. At the end of each block there is an option to load the next block.

Bibliography on: Symbiosis


Robert J. Robbins is a biologist, an educator, a science administrator, a publisher, an information technologist, and an IT leader and manager who specializes in advancing biomedical knowledge and supporting education through the application of information technology. More About:  RJR | OUR TEAM | OUR SERVICES | THIS WEBSITE

RJR: Recommended Bibliography 16 Dec 2018 at 01:41 Created: 


Symbiosis refers to an interaction between two or more different organisms living in close physical association, typically to the advantage of both. Symbiotic relationships were once thought to be exceptional situations. Recent studies, however, have shown that every multicellular eukaryote exists in a tight symbiotic relationship with billions of microbes. The associated microbial ecosystems are referred to as microbiome and the combination of a multicellular organism and its microbiota has been described as a holobiont. It seems "we are all lichens now."

Created with PubMed® Query: symbiosis NOT pmcbook NOT ispreviousversion

Citations The Papers (from PubMed®)

RevDate: 2018-12-15

Sudová R, Kohout P, Kolaříková Z, et al (2018)

Sympatric diploid and tetraploid cytotypes of Centaurea stoebe s.l. do not differ in arbuscular mycorrhizal communities and mycorrhizal growth response.

American journal of botany [Epub ahead of print].

PREMISE OF THE STUDY: Genome duplication is associated with multiple changes at different levels, including interactions with pollinators and herbivores. Yet little is known whether polyploidy may also shape belowground interactions.

METHODS: To elucidate potential ploidy-specific interactions with arbuscular mycorrhizal fungi (AMF), we compared mycorrhizal colonization and assembly of AMF communities in roots of diploid and tetraploid Centaurea stoebe s.l. (Asteraceae) co-occurring in a Central European population. In a follow-up greenhouse experiment, we tested inter-cytotype differences in mycorrhizal growth response by combining ploidy, substrate, and inoculation with native AMF in a full-factorial design.

KEY RESULTS: All sampled plants were highly colonized by AMF, with the Glomeraceae predominating. AMF-community composition revealed by 454-pyrosequencing reflected the spatial distribution of the hosts, but not their ploidy level or soil characteristics. In the greenhouse experiment, the tetraploids produced more shoot biomass than the diploids did when grown in a more fertile substrate, while no inter-cytotype differences were found in a less fertile substrate. AMF inoculation significantly reduced plant growth and improved P uptake, but its effects did not differ between the cytotypes.

CONCLUSIONS: The results do not support our hypotheses that the cytotype structure in a mixed-ploidy population of C. stoebe is mirrored in AMF-community composition and that ploidy-specific fungal communities contribute to cytotype co-existence. Causes and implications of the observed negative growth response to AMF are discussed.

RevDate: 2018-12-15

Shah A, Prasad S, Rastogi B, et al (2018)

Altered structural connectivity of the motor subnetwork in multiple system atrophy with cerebellar features.

European radiology pii:10.1007/s00330-018-5874-4 [Epub ahead of print].

OBJECTIVES: To investigate the structural connectivity of the motor subnetwork in multiple system atrophy with cerebellar features (MSA-C), a distinct subtype of MSA, characterized by predominant cerebellar symptoms.

METHODS: Twenty-three patients with MSA-C and 25 age- and gender-matched healthy controls were recruited for the study. Disease severity was quantified using the Unified Multiple System Atrophy Rating Scale (UMSARS). Diffusion MRI images were acquired and used to compute the structural connectomes (SCs) using probabilistic fiber tracking. The motor network with 12 brain regions and 26 cerebellar regions was extracted and was compared between the groups using analysis of variance at a global (network-wide), nodal (at each node), and edge (at each connection) levels, and was corrected for multiple comparisons. In addition, the acquired connectivity measures were correlated with duration of illness, total Unified MSA Rating Scale (UMSARS), and the motor component score.

RESULTS: Significantly lower global network metrics-global density, transitivity, clustering coefficient, and characteristic path length-were observed in MSA-C (corrected p < 0.05). Reduced nodal strength was observed in the bilateral ventral diencephalon, the left thalamus, and several cerebellar regions. Network-based statistics revealed significant abnormal edge-wise connectivity in 40 connections (corrected p < 0.01), with majority of deficits observed in the cerebellum. Finally, significant negative correlations were observed between UMSARS scores and thalamic and cerebellar connectivity (p < 0.05) as well as between duration of illness and cerebellar connectivity.

CONCLUSIONS: Abnormal connectivity of the basal ganglia and cerebellar network may be causally implicated for the motor features observed in MSA-C.

KEY POINTS: • Structural connectivity of the motor subnetwork was explored in patients with multiple system atrophy with cerebellar features (MSA-C) using probabilistic tractography. • The motor subnetwork in MSA-C has significant alterations in both basal ganglia and cerebellar connectivity, with a higher extent of abnormality in the cerebellum. • These findings may be causally implicated for the motor features of cerebellar dysfunction and parkinsonism observed in MSA-C.

RevDate: 2018-12-14

McClave SA, RG Martindale (2018)

Why do current strategies for optimal nutritional therapy neglect the microbiome?.

Nutrition (Burbank, Los Angeles County, Calif.), 60:100-105 pii:S0899-9007(18)30511-2 [Epub ahead of print].

Strategies for providing optimal nutritional therapy have evolved over time, with the emphasis on specific directives (such as route, use of immunonutrition, high protein, organ-specific formulas, etc.), achieving variable degrees of success for improving outcomes in the intensive care unit. As the largest immune organ in the body comprising the largest interface between the host and the external environment, the gut can have an amplifying effect on a pattern of dysbiosis, immune dysregulation, and multiple organ failure seen in the critically ill patient. Conversely, maintenance of gut integrity can serve to restore a pattern of homeostasis, appropriate immune responses, symbiosis, and clinical recovery. Simply providing refined polymeric formulas as enteral nutrition may not take full advantage of the potential for optimal outcome that could be derived by giving therapy designed to directly stimulate gut defenses and support the intestinal microbiota. This article describes a series of strategies (such as use of intact whole food formulas, soluble fiber, fecal microbial transplantation, serum bovine immunoglobulin, or agents to promote commensal behavior) that should modulate the gut microbiome and shift the critically ill patient toward a pattern of health and recovery.

RevDate: 2018-12-14

Sinnesael A, Eeckhout S, Janssens SB, et al (2018)

Detection of Burkholderia in the seeds of Psychotria punctata (Rubiaceae) - Microscopic evidence for vertical transmission in the leaf nodule symbiosis.

PloS one, 13(12):e0209091 pii:PONE-D-18-20790.

BACKGROUND AND AIMS: The bacterial leaf nodule symbiosis is a close interaction between endophytes and their plant hosts, mainly within the coffee family. The interaction between Rubiaceae species and Burkholderia bacteria is unique due to its obligate nature, high specificity, and predominantly vertical transmission of the endophytes to the next generation of host plants. This vertical transmission is intriguing since it is the basis for the uniqueness of the symbiosis. However, unequivocal evidence of the location of the endophytes in the seeds is lacking. The aim of this paper is therefore to demonstrate the presence of the host specific endophyte in the seeds of Psychotria punctata and confirm its precise location. In addition, the suggested location of the endophyte in other parts of the host plant is investigated.

METHODS: To identify and locate the endophyte in Psychotria punctata, a two-level approach was adopted using both a molecular screening method and fluorescent in situ hybridisation microscopy.

KEY RESULTS: The endophytes, molecularly identified as Candidatus Burkholderia kirkii, were detected in the leaves, vegetative and flower buds, anthers, gynoecium, embryos, and young twigs. In addition, they were in situ localised in leaves, flowers and shoot apical meristems, and, for the first time, in between the cotyledons of the embryos.

CONCLUSIONS: Both independent techniques detected the host specific endophyte in close proximity to the shoot apical meristem of the embryo, which confirms for the first time the exact location of the endophytes in the seeds. This study provides reliable proof that the endophytes are maintained throughout the growth and development of the host plant and are transmitted vertically to the offspring.

RevDate: 2018-12-14

Brodl E, Winkler A, P Macheroux (2018)

Molecular Mechanisms of Bacterial Bioluminescence.

Computational and structural biotechnology journal, 16:551-564 pii:S2001-0370(18)30154-5.

Bioluminescence refers to the production of light by living organisms. Bioluminescent bacteria with a variety of bioluminescence emission characteristics have been identified in Vibrionaceae, Shewanellaceae and Enterobacteriaceae. Bioluminescent bacteria are mainly found in marine habitats and they are either free-floating, sessile or have specialized to live in symbiosis with other marine organisms. On the molecular level, bioluminescence is enabled by a cascade of chemical reactions catalyzed by enzymes encoded by the lux operon with the gene order luxCDABEG. The luxA and luxB genes encode the α- and β- subunits, respectively, of the enzyme luciferase producing the light emitting species. LuxC, luxD and luxE constitute the fatty acid reductase complex, responsible for the synthesis of the long-chain aldehyde substrate and luxG encodes a flavin reductase. In bacteria, the heterodimeric luciferase catalyzes the monooxygenation of long-chain aliphatic aldehydes to the corresponding acids utilizing reduced FMN and molecular oxygen. The energy released as a photon results from an excited state flavin-4a-hydroxide, emitting light centered around 490 nm. Advances in the mechanistic understanding of bacterial bioluminescence have been spurred by the structural characterization of protein encoded by the lux operon. However, the number of available crystal structures is limited to LuxAB (Vibrio harveyi), LuxD (Vibrio harveyi) and LuxF (Photobacterium leiognathi). Based on the crystal structure of LuxD and homology models of LuxC and LuxE, we provide a hypothetical model of the overall structure of the LuxCDE fatty acid reductase complex that is in line with biochemical observations.

RevDate: 2018-12-14

Nagel R, Bieber JE, Schmidt-Dannert MG, et al (2018)

A Third Class: Functional Gibberellin Biosynthetic Operon in Beta-Proteobacteria.

Frontiers in microbiology, 9:2916.

The ability of plant-associated microbes to produce gibberellin A (GA) phytohormones was first described for the fungal rice pathogen Gibberella fujikuroi in the 1930s. Recently the capacity to produce GAs was shown for several bacteria, including symbiotic alpha-proteobacteria (α-rhizobia) and gamma-proteobacteria phytopathogens. All necessary enzymes for GA production are encoded by a conserved operon, which appears to have undergone horizontal transfer between and within these two phylogenetic classes of bacteria. Here the operon was shown to be present and functional in a third class, the beta-proteobacteria, where it is found in several symbionts (β-rhizobia). Conservation of function was examined by biochemical characterization of the enzymes encoded by the operon from Paraburkholderia mimosarum LMG 23256T. Despite the in-frame gene fusion between the short-chain alcohol dehydrogenase/reductase and ferredoxin, the encoded enzymes exhibited the expected activity. Intriguingly, together these can only produce GA9, the immediate precursor to the bioactive GA4, as the cytochrome P450 (CYP115) that catalyzes the final hydroxylation reaction is missing, similar to most α-rhizobia. However, phylogenetic analysis indicates that the operon from β-rhizobia is more closely related to examples from gamma-proteobacteria, which almost invariably have CYP115 and, hence, can produce bioactive GA4. This indicates not only that β-rhizobia acquired the operon by horizontal gene transfer from gamma-proteobacteria, rather than α-rhizobia, but also that they independently lost CYP115 in parallel to the α-rhizobia, further hinting at the possibility of detrimental effects for the production of bioactive GA4 by these symbionts.

RevDate: 2018-12-14

Franck S, Strodtman KN, Qiu J, et al (2018)

Transcriptomic Characterization of Bradyrhizobium diazoefficiens Bacteroids Reveals a Post-Symbiotic, Hemibiotrophic-Like Lifestyle of the Bacteria within Senescing Soybean Nodules.

International journal of molecular sciences, 19(12): pii:ijms19123918.

The transcriptional activity of Bradyrhizobium diazoefficens isolated from soybean nodules was monitored over the period from symbiosis to late plant nodule senescence. The bacteria retained a near constant level of RNA throughout this period, and the variation in genes demonstrating increased, decreased, and/or patterned transcriptional activity indicates that the bacteria are responding to the changing environment within the nodule as the plant cells progress from an organized cellular structure to an unorganized state of internal decay. The transcriptional variation and persistence of the bacteria suggest that the bacteria are adapting to their environment and acting similar to hemibiotrophs, which survive both as saprophytes on live plant tissues and then as necrophytes on decaying plant tissues. The host plant restrictions of symbiosis make B. diazoefficiens a highly specialized, restricted hemibiotroph.

RevDate: 2018-12-13

Saito R, Kabeya M, Nemoto Y, et al (2018)

Monitoring 137Cs concentrations in bird species occupying different ecological niches; game birds and raptors in Fukushima Prefecture.

Journal of environmental radioactivity, 197:67-73 pii:S0265-931X(17)31025-1 [Epub ahead of print].

This study was conducted to assess radiocesium accumulation in birds after the accident at Tokyo Electric Power Company's Fukushima Daiichi Nuclear Power Station in 2011, with a particular focus on 137Cs, which has a long physical half-life. Results of 137Cs monitoring in four game bird species including two pheasant species and two duck species (copper pheasant, green pheasant, spot-billed duck and mallard) were assessed in Fukushima Prefecture. We also obtained samples from rescued raptors that died during treatment or rehabilitation at the Wildlife Symbiosis Centre in Fukushima Prefecture because of severe injury. We measured the muscle concentrations of 137Cs in four of these raptor species (black kite, northern goshawk, peregrine falcon and ural owl). Comparison of the two pheasant species showed that the copper pheasants inhabiting forested areas had higher 137Cs concentrations in muscle (Bq/kg, fresh mass) than the green pheasants inhabiting mountainous areas near human habitation (i.e., Satoyama). No clear tendencies were observed in 137Cs concentration in muscle of copper pheasants over time, but a tendency to decrease was observed in green pheasants over time. The difference in tendencies between species may be attributable to differences in their food habits and its 137Cs concentration, and also differences in the situation of 137Cs accumulation in their habitat. No significant differences were observed in 137Cs concentration in muscle between the resident spot-billed duck and migratory mallard because of the comparatively short biological of effective half-life of radiocesium. Analysis of 137Cs concentration in muscle of raptor revealed that the concentration was similar to, or lower than, those of pheasants and ducks.

RevDate: 2018-12-13

Campos C, Carvalho M, Brígido C, et al (2018)

Symbiosis Specificity of the Preceding Host Plant Can Dominate but Not Obliterate the Association Between Wheat and Its Arbuscular Mycorrhizal Fungal Partners.

Frontiers in microbiology, 9:2920.

The symbiosis established between arbuscular mycorrhizal fungi (AMF) and roots of most land plants plays a key role in plant nutrient acquisition and alleviation of environmental stresses. Despite the ubiquity of the symbiosis, AMF and host species display significant specificity in their interactions. To clarify preferential associations between wheat (Triticum aestivum) and AMF, we characterized root AMF communities in the transition from two first host species, ryegrass (Lolium rigidum) and yellow-serradella (Ornithopus compressus), grown separately or together, to a second host (wheat), by sequencing the large subunit ribosomal DNA (LSU rDNA) gene. The response of AMF communities in wheat to prior soil disturbance - and consequently of the mycelial network [intact extraradical mycelium (ERM) vs. disrupted mycelium] established with either of the first hosts - was also investigated. Since the outcome of a specific host-symbiont interaction depends on the molecular responses of the host plant upon microbial colonization, we studied the expression of six key symbiosis-related genes in wheat roots. AMF communities on L. rigidum and O. compressus roots were clearly distinct. Within an undisturbed ERM, wheat AMF communities were similar to that of previous host, and O. compressus-wheat-AMF interactions supported a greater growth of wheat than L. rigidum-wheat-AMF interactions. This effect declined when ERM was disrupted, but generated a greater activation of symbiotic genes in wheat, indicating that plant symbiotic program depends on some extent on the colonizing symbiont propagule type. When a mixture of L. rigidum and O. compressus was planted, the wheat colonization pattern resembled that of O. compressus, although this was not reflected in a greater growth. These results show a lasting effect of previous hosts in shaping wheat AMF communities through an efficient use of the established ERM, although not completely obliterating host-symbiont specificity.

RevDate: 2018-12-14
CmpDate: 2018-12-14

Sánchez-Rangel D, Hernández-Domínguez EE, Pérez-Torres CA, et al (2018)

Environmental pH modulates transcriptomic responses in the fungus Fusarium sp. associated with KSHB Euwallacea sp. near fornicatus.

BMC genomics, 19(1):721.

BACKGROUND: The Ambrosia Fusarium Clade phytopathogenic Fusarium fungi species have a symbiotic relationship with ambrosia beetles in the genus Euwallacea (Coleoptera: Curculionidae). Related beetle species referred to as Euwallacea sp. near fornicatus have been spread in California, USA and are recognized as the causal agents of Fusarium dieback, a disease that causes mortality of many plant species. Despite the importance of this fungi, no transcriptomic resources have been generated. The datasets described here represent the first ever transcripts available for these species. We focused our study on the isolated species of Fusarium that is associated with one of the cryptic species referred to as Kuroshio Shot Hole Borer (KSHB) Euwallacea sp. near fornicatus.

RESULTS: Hydrogen concentration is a critical signal in fungi for growth and host colonization, the aim of this study was to evaluate the effect of different pH conditions on growth and gene expression of the fungus Fusarium sp. associated with KSHB. An RNA-seq approach was used to compare the gene expression of the fungus grown for 2 weeks in liquid medium at three different pH levels (5.0, 6.0, and 7.0). An unbuffered treatment was included to evaluate the capability of the fungus to change the pH of its environment and the impact in gene expression. The results showed that the fungus can grow and modulate its genetic expression at different pH conditions; however, growth was stunted in acidic pH in comparison with neutral pH. The results showed a differential expression pattern in each pH condition even when acidic conditions prevailed at the end of the experiment. After comparing transcriptomics data from the three treatments, we found a total of 4,943 unique transcripts that were differentially expressed.

CONCLUSIONS: We identified transcripts related to pH signaling such as the conserved PAL/RIM pathway, some transcripts related to secondary metabolism and other transcripts that were differentially expressed. Our analysis suggests possible mechanisms involved in pathogenicity in this novel Fusarium species. This is the first report that shows transcriptomic data of this pathogen as well as the first report of genes and proteins involved in their metabolism identifying potential virulence factors.

RevDate: 2018-12-14
CmpDate: 2018-12-14

Bok E, Mazurek J, Myc A, et al (2018)

Comparison of Commensal Escherichia coli Isolates from Adults and Young Children in Lubuskie Province, Poland: Virulence Potential, Phylogeny and Antimicrobial Resistance.

International journal of environmental research and public health, 15(4):.

Commensal Escherichia coli population is a dynamic structure which may be important in the pathogenesis of extraintestinal infections. The aim of this study was the comparison of genetic diversity of commensal E. coli isolates from two age group-adults and young children. E. coli strains were isolated on MacConkey agar and identified by biochemical tests. Determination of four major phylogenetic groups, identification of virulence genes and antimicrobial resistance determinants were performed by using multiplex or simplex PCR. Phenotypic analysis of resistance was based on disc-diffusion method. The prevalence of virulence genes was significantly higher among isolates from adults than from young children. Phylogroup B2 predominated among E. coli from adults, whereas phylogroup A was the most common in isolates from young children. The analyses of antimicrobial resistance revealed that resistance to at least one antimicrobial agent and multidrug-resistance were detected significantly more frequent in the isolates from adults than from young children. This study documented that the commensal E. coli isolates from adults showed greater genetic diversity than from young children and constitutes a substantial reservoir of the virulence genes typical for extraintestinal pathogenic E. coli.

RevDate: 2018-12-14
CmpDate: 2018-12-14

Moog D, UG Maier (2018)

Explaining the Origin of Three-Membrane-Bound Plastids in Dinoflagellates and Euglenophytes: Kleptoplastidy via Myzocytosis?.

BioEssays : news and reviews in molecular, cellular and developmental biology, 40(2):.

RevDate: 2018-12-14
CmpDate: 2018-12-14

Steinert G, Rohde S, Janussen D, et al (2017)

Host-specific assembly of sponge-associated prokaryotes at high taxonomic ranks.

Scientific reports, 7(1):2542.

Sponges (Porifera) are abundant and diverse members of benthic filter feeding communities in most marine ecosystems, from the deep sea to tropical reefs. A characteristic feature is the associated dense and diverse prokaryotic community present within the sponge mesohyl. Previous molecular genetic studies revealed the importance of host identity for the community composition of the sponge-associated microbiota. However, little is known whether sponge host-specific prokaryotic community patterns observed at 97% 16S rRNA gene sequence similarity are consistent at high taxonomic ranks (from genus to phylum level). In the present study, we investigated the prokaryotic community structure and variation of 24 sponge specimens (seven taxa) and three seawater samples from Sweden. Results show that the resemblance of prokaryotic communities at different taxonomic ranks is consistent with patterns present at 97% operational taxonomic unit level.

RevDate: 2018-12-12

George F, Daniel C, Thomas M, et al (2018)

Occurrence and Dynamism of Lactic Acid Bacteria in Distinct Ecological Niches: A Multifaceted Functional Health Perspective.

Frontiers in microbiology, 9:2899.

Lactic acid bacteria (LAB) are representative members of multiple ecosystems on earth, displaying dynamic interactions within animal and plant kingdoms in respect with other microbes. This highly heterogeneous phylogenetic group has coevolved with plants, invertebrates, and vertebrates, establishing either mutualism, symbiosis, commensalism, or even parasitism-like behavior with their hosts. Depending on their location and environment conditions, LAB can be dominant or sometimes in minority within ecosystems. Whatever their origins and relative abundance in specific anatomic sites, LAB exhibit multifaceted ecological and functional properties. While some resident LAB permanently inhabit distinct animal mucosal cavities, others are provided by food and may transiently occupy the gastrointestinal tract. It is admitted that the overall gut microbiome has a deep impact on health and diseases. Here, we examined the presence and the physiological role of LAB in the healthy human and several animal microbiome. Moreover, we also highlighted some dysbiotic states and related consequences for health, considering both the resident and the so-called "transionts" microorganisms. Whether LAB-related health effects act collectively or follow a strain-specificity dogma is also addressed. Besides the highly suggested contribution of LAB to interplay with immune, metabolic, and even brain-axis regulation, the possible involvement of LAB in xenobiotic detoxification processes and metal equilibrium is also tackled. Recent technological developments such as functional metagenomics, metabolomics, high-content screening and design in vitro and in vivo experimental models now open new horizons for LAB as markers applied for disease diagnosis, susceptibility, and follow-up. Moreover, identification of general and more specific molecular mechanisms based on antioxidant, antimicrobial, anti-inflammatory, and detoxifying properties of LAB currently extends their selection and promising use, either as probiotics, in traditional and functional foods, for dedicated treatments and mostly for maintenance of normobiosis and homeostasis.

RevDate: 2018-12-12

Paymaneh Z, Gryndler M, Konvalinková T, et al (2018)

Soil Matrix Determines the Outcome of Interaction Between Mycorrhizal Symbiosis and Biochar for Andropogon gerardii Growth and Nutrition.

Frontiers in microbiology, 9:2862.

Biochar has been heralded as a multipurpose soil amendment to sustainably increase soil fertility and crop yields, affect soil hydraulic properties, reduce nutrient losses, and sequester carbon. Some of the most spectacular results of biochar (and organic nutrient) inputs are the terra preta soils in the Amazon, dark anthropogenic soils with extremely high fertility sustained over centuries. Such soil improvements have been particularly difficult to achieve on a short run, leading to speculations that biochar may need to age (weather) in soil to show its best. Further, interaction of biochar with arbuscular mycorrhizal fungi (AMF), important root symbionts of a great majority of terrestrial plants including most agricultural crops, remains little explored. To study the effect of aged biochar on highly mycotrophic Andropogon gerardii plants and their associated AMF, we made use of softwood biochar, collected from a historic charcoal burning site. This biochar (either untreated or chemically activated, the latter serving as a proxy for freshly prepared biochar) was added into two agricultural soils (acid or alkaline), and compared to soils without biochar. These treatments were further crossed with inoculation with a synthetic AMF community to address possible interactions between biochar and the AMF. Biochar application was generally detrimental for growth and mineral nutrition of our experimental plants, but had no effect on the extent of their root colonized by the AMF, nor did it affect composition of their root-borne AMF communities. In contrast, biochar affected development of two out of five AMF (Claroideoglomus and Funneliformis) in the soil. Establishment of symbiosis with AMF largely mitigated biochar-induced suppression of plant growth and mineral nutrition, mainly by improving plant acquisition of phosphorus. Both mycorrhizal and non-mycorrhizal plants grew well in the acid soil without biochar application, whereas non-mycorrhizal plants remained stunted in the alkaline soils under all situations (with or without biochar). These different and strong effects indicate that response of plants to biochar application are largely dependent on soil matrix and also on microbes such as AMF, and call for further research to enable qualified predictions of the effects of different biochar applications on field-grown crops and soil processes.

RevDate: 2018-12-12

Nicolás C, Martin-Bertelsen T, Floudas D, et al (2018)

The soil organic matter decomposition mechanisms in ectomycorrhizal fungi are tuned for liberating soil organic nitrogen.

The ISME journal pii:10.1038/s41396-018-0331-6 [Epub ahead of print].

Many trees form ectomycorrhizal symbiosis with fungi. During symbiosis, the tree roots supply sugar to the fungi in exchange for nitrogen, and this process is critical for the nitrogen and carbon cycles in forest ecosystems. However, the extents to which ectomycorrhizal fungi can liberate nitrogen and modify the soil organic matter and the mechanisms by which they do so remain unclear since they have lost many enzymes for litter decomposition that were present in their free-living, saprotrophic ancestors. Using time-series spectroscopy and transcriptomics, we examined the ability of two ectomycorrhizal fungi from two independently evolved ectomycorrhizal lineages to mobilize soil organic nitrogen. Both species oxidized the organic matter and accessed the organic nitrogen. The expression of those events was controlled by the availability of glucose and inorganic nitrogen. Despite those similarities, the decomposition mechanisms, including the type of genes involved as well as the patterns of their expression, differed markedly between the two species. Our results suggest that in agreement with their diverse evolutionary origins, ectomycorrhizal fungi use different decomposition mechanisms to access organic nitrogen entrapped in soil organic matter. The timing and magnitude of the expression of the decomposition activity can be controlled by the below-ground nitrogen quality and the above-ground carbon supply.

RevDate: 2018-12-12

Harding K, Turk-Kubo KA, Sipler RE, et al (2018)

Symbiotic unicellular cyanobacteria fix nitrogen in the Arctic Ocean.

Proceedings of the National Academy of Sciences of the United States of America pii:1813658115 [Epub ahead of print].

Biological dinitrogen (N2) fixation is an important source of nitrogen (N) in low-latitude open oceans. The unusual N2-fixing unicellular cyanobacteria (UCYN-A)/haptophyte symbiosis has been found in an increasing number of unexpected environments, including northern waters of the Danish Straight and Bering and Chukchi Seas. We used nanoscale secondary ion mass spectrometry (nanoSIMS) to measure 15N2 uptake into UCYN-A/haptophyte symbiosis and found that UCYN-A strains identical to low-latitude strains are fixing N2 in the Bering and Chukchi Seas, at rates comparable to subtropical waters. These results show definitively that cyanobacterial N2 fixation is not constrained to subtropical waters, challenging paradigms and models of global N2 fixation. The Arctic is particularly sensitive to climate change, and N2 fixation may increase in Arctic waters under future climate scenarios.

RevDate: 2018-12-12
CmpDate: 2018-12-12

Fan M, Liu Z, Nan L, et al (2018)

Isolation, characterization, and selection of heavy metal-resistant and plant growth-promoting endophytic bacteria from root nodules of Robinia pseudoacacia in a Pb/Zn mining area.

Microbiological research, 217:51-59.

Multiple heavy metals (HMs) commonly coexist in mining areas, which highlights the necessity to select multiple HM-resistant plant growth-promoting bacteria for improving phytoremediation efficiency. In this study, we isolated and characterized 82 endophytic bacteria from the root nodules of black locust (Robinia pseudoacacia) grown in a Pb-Zn mining area. There were 80 isolates showing resistance to four HMs, 0.01-18.0 mM/L for Cd, 0.2-40.0 mM/L for Zn, 0.3-2.2 mM/L for Pb, and 0.2-1.4 mM/L for Cu. Indole-3-acetic acid production, siderophore production, and 1-aminocyclopropane-1-carboxylate deaminase activity were detected in 43, 50, and 17 isolates, respectively. Two symbiotic isolates selected with the highest potential for HM resistance and PGP traits, designated Mesorhizobium loti HZ76 and Agrobacterium radiobacter HZ6, were evaluated for promotion of plant growth and metal uptake by R. pseudoacacia seedlings grown in pots containing different levels of Cd, Zn, Pb, or Cu. HZ76 significantly increased plant shoot biomass, while HZ6 did not, compared with non-inoculated controls. The results indicate that inoculation with HZ76 or HZ6 relieved HM stress in the plants, depending on the type and concentration of HM in the treatment. Mesorhizobium loti HZ76 may be a better candidate for application in phytoremediation than A. radiobacter HZ6. The microsymbiosis between HM-resistant rhizobia and R. pseudoacacia is an interesting mutualistic system for phytoremediation in mining areas contaminated with multiple HMs.

RevDate: 2018-12-12
CmpDate: 2018-12-12

Huang X, Zhu J, Cai Z, et al (2018)

Profiles of quorum sensing (QS)-related sequences in phycospheric microorganisms during a marine dinoflagellate bloom, as determined by a metagenomic approach.

Microbiological research, 217:1-13.

The complicated relationships among environmental microorganisms are regulated by quorum sensing (QS). Understanding QS-based signals could shed light on the interactions between microbial communities in certain environments. Although QS characteristics have been widely discussed, few studies have been conducted on the role of QS in phycospheric microorganisms. Here, we used metagenomics to examine the profile of AI-1 (AinS, HdtS, LuxI) and AI-2 (LuxS) autoinducers from a deeply sequenced microbial database, obtained from a complete dinoflagellate bloom. A total of 3001 putative AI-1 homologs and 130 AI-2 homologs were identified. The predominant member among the AI groups was HdtS. The abundance of HdtS, AinS, and LuxS increased as the bloom developed, whereas the abundance of LuxI showed the opposite trend. Phylogenetic analysis suggested that HdtS and LuxI synthase originated mainly from alpha-, beta-, and gamma-Proteobacteria, whereas AinS synthase originated solely from Vibrionales. In comparison to AI-1, the sequences related to AI-2 (LuxS) demonstrated a much wider taxonomic coverage. Some significant correlations were found between dominant species and QS signals. In addition to the QS, we also performed parallel analysis of the quorum quenching (QQ) sequences. In comparison to QS, the relative abundance of QQ signals was lower; however, an obvious frequency correlation was observed. These results suggested that QS and QQ signals co-participate in regulating microbial communities during an algal bloom. These data helped to reveal the characteristic behavior of algal symbiotic bacteria, and facilitated a better understanding of microbial dynamics during an algal bloom event from a chemical ecological perspective.

RevDate: 2018-12-12
CmpDate: 2018-12-12

Gerardo N, G Hurst (2017)

Q&A: Friends (but sometimes foes) within: the complex evolutionary ecology of symbioses between host and microbes.

BMC biology, 15(1):126.

Over the past decade, there has been a pronounced shift in the study of host-microbe associations, with recognition that many of these associations are beneficial, and often critical, for a diverse array of hosts. There may also be pronounced benefits for the microbes, though this is less well empirically understood. Significant progress has been made in understanding how ecology and evolution shape simple associations between hosts and one or a few microbial species, and this work can serve as a foundation to study the ecology and evolution of host associations with their often complex microbial communities (microbiomes).

RevDate: 2018-12-12
CmpDate: 2018-12-12

Martino ME, F Leulier (2017)

Guest editorial: Microbiota: Microbiota and animal ecology, evolution and physiology: back to the future.

Current opinion in microbiology, 38:viii-x.

RevDate: 2018-12-11

Brown A, E Akçay (2018)

Evolution of transmission mode in conditional mutualisms with spatial variation in symbiont quality.

Evolution; international journal of organic evolution [Epub ahead of print].

Many symbioses have costs and benefits to their hosts that vary with the environmental context, which itself may vary in space. The same symbiont may be a mutualist in one location and a parasite in another. Such spatially conditional mutualisms pose a dilemma for hosts, who might evolve (higher or lower) horizontal or vertical transmission to increase their chances of being infected only where the symbiont is beneficial. To determine how transmission in hosts might evolve, we modeled transmission evolution where the symbiont had a spatially conditional effect on either host lifespan or fecundity. We found that over ecological time, symbionts that affected lifespan but not fecundity led to high frequencies of infected hosts in areas where the symbiont was beneficial and low frequencies elsewhere. In response, hosts evolved increased horizontal transmission only when the symbiont affected lifespan. We also modeled transmission evolution in symbionts, which evolved high horizontal and vertical transmission, indicating a possible host-symbiont conflict over transmission mode. Our results suggest an eco-evolutionary feedback where the component of host fitness affected by a conditionally mutualistic symbiont in turn determines its distribution in the population, and, through this, the transmission mode that evolves. This article is protected by copyright. All rights reserved.

RevDate: 2018-12-11

Tullio LD, Nakatani AS, Gomes DF, et al (2018)

Revealing the roles of y4wF and tidC genes in Rhizobium tropici CIAT 899: biosynthesis of indolic compounds and impact on symbiotic properties.

Archives of microbiology pii:10.1007/s00203-018-1607-y [Epub ahead of print].

Rhizobium tropici CIAT 899 is a strain known by its ability to nodulate a broad range of legume species, to synthesize a variety of Nod factors, its tolerance of abiotic stresses, and its high capacity to fix atmospheric N2, especially in symbiosis with common bean (Phaseolus vulgaris L.). Genes putatively related to the synthesis of indole acetic acid (IAA) have been found in the symbiotic plasmid of CIAT 899, in the vicinity of the regulatory nodulation gene nodD5, and, in this study, we obtained mutants for two of these genes, y4wF and tidC (R. tropici indole-3-pyruvic acid decarboxylase), and investigated their expression in the absence and presence of tryptophan (TRP) and apigenin (API). In general, mutations of both genes increased exopolysaccharide (EPS) synthesis and did not affect swimming or surface motility; mutations also delayed nodule formation, but increased competitiveness. We found that the indole-3-acetamide (IAM) pathway was active in CIAT 899 and not affected by the mutations, and-noteworthy-that API was required to activate the tryptamine (TAM) and the indol-3-pyruvic acid (IPyA) pathways in all strains, particularly in the mutants. High up-regulation of y4wF and tidC genes was observed in both the wild-type and the mutant strains in the presence of API. The results obtained revealed an intriguing relationship between IAA metabolism and nod-gene-inducing activity in R. tropici CIAT 899. We discuss the IAA pathways, and, based on our results, we attribute functions to the y4wF and tidC genes of R. tropici.

RevDate: 2018-12-11

Chang Y, Liu H, Liu M, et al (2018)

The draft genomes of five agriculturally important African orphan crops.

GigaScience pii:5232229 [Epub ahead of print].

Background: Continuous growth of the world population is expected to double the worldwide demand for food by 2050. Eighty-eight percent of countries current face a serious burden of malnutrition, especially in Africa and South and South-East Asia. About 95% of the food energy needs of humans are fulfilled by just 30 species, of which wheat, maize and rice provide the majority of calories. Therefore, to diversify and stabilize global food supply, enhance agricultural productivity and tackle malnutrition, greater use of neglected or underutilized local plants (so-called "orphan crops," but also including a few plants of special significance to agriculture, agroforestry and nutrition) could be a partial solution.

Results: Here, we present draft genome information from five agriculturally, biologically, medicinally and economically important underutilized plants native to Africa; Vigna subterranea, Lablab purpureus, Faidherbia albida, Sclerocarya birrea, and Moringa oleifera. Assembled genomes range in size from 217 to 654 Mb. In V. subterranea, L. purpureus, F. albida, S. birrea and M. oleifera we have predicted 31707, 20946, 28979, 18937, 18451 protein-coding genes, respectively. By further analysing the expansion and contraction of selected gene families, we have characterized root nodule symbiosis genes, transcription factors and starch biosynthesis-related genes in these genomes.

Conclusions: These genome data will be useful to identify and characterize agronomically important genes and understand their modes of action, enabling genomics-based, evolutionary studies, and breeding strategies to design faster, more focused and predictable crop improvement programs.

RevDate: 2018-12-11

Gutiérrez-García K, Bustos-Díaz ED, Corona-Gómez JA, et al (2018)

Cycad coralloid roots contain bacterial communities including cyanobacteria and Caulobacter spp that encode niche-specific biosynthetic gene clusters.

Genome biology and evolution pii:5238076 [Epub ahead of print].

Cycads are the only early seed plants that have evolved a specialized root to host endophytic bacteria that fix nitrogen. To provide evolutionary and functional insights into this million-year old symbiosis, we investigate endophytic bacterial sub-communities isolated from coralloid roots of species from Dioon (Zamiaceae) sampled from their natural habitats. We employed a sub-community co-culture experimental strategy to reveal both predominant and rare bacteria, which were characterized using phylogenomics and detailed metabolic annotation. Diazotrophic plant endophytes, including Bradyrhizobium, Burkholderia, Mesorhizobium, Rhizobium and Nostoc species, dominated the epiphyte-free sub-communities. Draft genomes of six cyanobacteria species were obtained after shotgun metagenomics of selected sub-communities. This data was used for whole-genome inferences that suggest two Dioon-specific monophyletic groups, and a level of specialization characteristic of co-evolved symbiotic relationships. Furthermore, the genomes of these cyanobacteria were found to encode unique biosynthetic gene clusters, predicted to direct the synthesis of specialized metabolites, mainly involving peptides. After combining genome mining with detection of pigment emissions using multiphoton excitation fluorescence microscopy, we also show that Caulobacter species co-exist with cyanobacteria, and may interact with them by means of a novel indigoidine-like specialized metabolite. We provide an unprecedented view of the composition of the cycad coralloid root, including phylogenetic and functional patterns mediated by specialized metabolites that may be important for the evolution of ancient symbiotic adaptations.

RevDate: 2018-12-11

Liang J, Hoffrichter A, Brachmann A, et al (2018)

Complete genome of Rhizobium leguminosarum Norway, an ineffective Lotus micro-symbiont.

Standards in genomic sciences, 13:36 pii:336.

Rhizobia bacteria engage in nitrogen-fixing root nodule symbiosis, a mutualistic interaction with legume plants in which a bidirectional nutrient exchange takes place. Occasionally, this interaction is suboptimal resulting in the formation of ineffective nodules in which little or no atmospheric nitrogen fixation occurs. Rhizobium leguminosarum Norway induces ineffective nodules in a wide range of Lotus hosts. To investigate the basis of this phenotype, we sequenced the complete genome of Rl Norway and compared it to the genome of the closely related strain R. leguminosarum bv. viciae 3841. The genome comprises 7,788,085 bp, distributed on a circular chromosome containing 63% of the genomic information and five large circular plasmids. The functionally classified bacterial gene set is distributed evenly among all replicons. All symbiotic genes (nod, fix, nif) are located on the pRLN3 plasmid. Whole genome comparisons revealed differences in the metabolic repertoire and in protein secretion systems, but not in classical symbiotic genes.

RevDate: 2018-12-11

Montecillo AD, Raymundo AK, Papa IA, et al (2018)

Complete Genome Sequence of Rhizobium sp. Strain 11515TR, Isolated from Tomato Rhizosphere in the Philippines.

Microbiology resource announcements, 7(7): pii:MRA00903-18.

Rhizobium sp. strain 11515TR was isolated from the rhizosphere of tomato in Laguna, Philippines. The 7.07-Mb complete genome comprises three replicons, one chromosome, and two plasmids, with a G+C content of 59.4% and 6,720 protein-coding genes. The genome encodes gene clusters supporting rhizosphere processes, plant symbiosis, and secondary bioactive metabolites.

RevDate: 2018-12-11

Nguyen HDT, Cloutier S, ESP Bromfield (2018)

Complete Genome Sequence of Bradyrhizobium ottawaense OO99T, an Efficient Nitrogen-Fixing Symbiont of Soybean.

Microbiology resource announcements, 7(21): pii:MRA01477-18.

We present the complete genome sequence of Bradyrhizobium ottawaense strain OO99T, a nitrogen-fixing bacterium from root nodules of soybean. The genome consists of a single 8.6-Mb chromosome and includes a symbiosis island. Genes involved in symbiotic nitrogen fixation, stress response, resistance to antibiotics, and toxic compounds were detected.

RevDate: 2018-12-11

Andryuschenko SV, Ivanova EV, Perunova NB, et al (2018)

Draft Genome Sequence of Bifidobacterium bifidum Strain ICIS-310, Isolated from the Feces of a Healthy 5-Year-Old Child from Orenburg, Russia.

Microbiology resource announcements, 7(18): pii:MRA01271-18.

This report describes the draft genome sequence of Bifidobacterium bifidum strain ICIS-310, isolated from the feces of a healthy 5-year-old child from Orenburg, Russia. The size of the genome was 2,219,632 bp (62.4% G+C content). Annotation revealed 1,886 coding sequences, including 1,718 proteins, 6 rRNA genes, and 52 tRNA genes.

RevDate: 2018-12-11

Brock DA, Haselkorn TS, Garcia JR, et al (2018)

Diversity of Free-Living Environmental Bacteria and Their Interactions With a Bactivorous Amoeba.

Frontiers in cellular and infection microbiology, 8:411.

A small subset of bacteria in soil interact directly with eukaryotes. Which ones do so can reveal what is important to a eukaryote and how eukaryote defenses might be breached. Soil amoebae are simple eukaryotic organisms and as such could be particularly good for understanding how eukaryote microbiomes originate and are maintained. One such amoeba, Dictyostelium discoideum, has both permanent and temporary associations with bacteria. Here we focus on culturable bacterial associates in order to interrogate their relationship with D. discoideum. To do this, we isolated over 250 D. discoideum fruiting body samples from soil and deer feces at Mountain Lake Biological Station. In one-third of the wild D. discoideum we tested, one to six bacterial species were found per fruiting body sorus (spore mass) for a total of 174 bacterial isolates. The remaining two-thirds of D. discoideum fruiting body samples did not contain culturable bacteria, as is thought to be the norm. A majority (71.4%) of the unique bacterial haplotypes are in Proteobacteria. The rest are in either Actinobacteria, Bacteriodetes, or Firmicutes. The highest bacterial diversity was found in D. discoideum fruiting bodies originating from deer feces (27 OTUs), greater than either of those originating in shallow (11 OTUs) or in deep soil (4 OTUs). Rarefaction curves and the Chao1 estimator for species richness indicated the diversity in any substrate was not fully sampled, but for soil it came close. A majority of the D. discoideum-associated bacteria were edible by D. discoideum and supported its growth (75.2% for feces and 81.8% for soil habitats). However, we found several bacteria genera were able to evade phagocytosis and persist in D. discoideum cells through one or more social cycles. This study focuses not on the entire D. discoideum microbiome, but on the culturable subset of bacteria that have important eukaryote interactions as prey, symbionts, or pathogens. These eukaryote and bacteria interactions may provide fertile ground for investigations of bacteria using amoebas to gain an initial foothold in eukaryotes and of the origins of symbiosis and simple microbiomes.

RevDate: 2018-12-11

Kenkel CD, LK Bay (2018)

Exploring mechanisms that affect coral cooperation: symbiont transmission mode, cell density and community composition.

PeerJ, 6:e6047 pii:6047.

The coral symbiosis is the linchpin of the reef ecosystem, yet the mechanisms that promote and maintain cooperation between hosts and symbionts have not been fully resolved. We used a phylogenetically controlled design to investigate the role of vertical symbiont transmission, an evolutionary mechanism in which symbionts are inherited directly from parents, predicted to enhance cooperation and holobiont fitness. Six species of coral, three vertical transmitters and their closest horizontally transmitting relatives, which exhibit environmental acquisition of symbionts, were fragmented and subjected to a 2-week thermal stress experiment. Symbiont cell density, photosynthetic function and translocation of photosynthetically fixed carbon between symbionts and hosts were quantified to assess changes in physiological performance and cooperation. All species exhibited similar decreases in symbiont cell density and net photosynthesis in response to elevated temperature, consistent with the onset of bleaching. Yet baseline cooperation, or translocation of photosynthate, in ambient conditions and the reduction in cooperation in response to elevated temperature differed among species. Although Porites lobata and Galaxea acrhelia did exhibit the highest levels of baseline cooperation, we did not observe universally higher levels of cooperation in vertically transmitting species. Post hoc sequencing of the Symbiodinium ITS-2 locus was used to investigate the potential role of differences in symbiont community composition. Interestingly, reductions in cooperation at the onset of bleaching tended to be associated with increased symbiont community diversity among coral species. The theoretical benefits of evolving vertical transmission are based on the underlying assumption that the host-symbiont relationship becomes genetically uniform, thereby reducing competition among symbionts. Taken together, our results suggest that it may not be vertical transmission per se that influences host-symbiont cooperation, but genetic uniformity of the symbiont community, although additional work is needed to test this hypothesis.

RevDate: 2018-12-11

Kariman K, Barker SJ, M Tibbett (2018)

Structural plasticity in root-fungal symbioses: diverse interactions lead to improved plant fitness.

PeerJ, 6:e6030 pii:6030.

Root-fungal symbioses such as mycorrhizas and endophytes are key components of terrestrial ecosystems. Diverse in trophy habits (obligate, facultative or hemi-biotrophs) and symbiotic relations (from mutualism to parasitism), these associations also show great variability in their root colonization and nutritional strategies. Specialized interface structures such as arbuscules and Hartig nets are formed by certain associations while others are restricted to non-specialized intercellular or intracellular hyphae in roots. In either case, there are documented examples of active nutrient exchange, reinforcing the fact that specialized structures used to define specific mycorrhizal associations are not essential for reciprocal exchange of nutrients and plant growth promotion. In feremycorrhiza (with Austroboletus occidentalis and eucalypts), the fungal partner markedly enhances plant growth and nutrient acquisition without colonizing roots, emphasizing that a conventional focus on structural form of associations may have resulted in important functional components of rhizospheres being overlooked. In support of this viewpoint, mycobiome studies using the state-of-the-art DNA sequencing technologies have unearthed much more complexity in root-fungal relationships than those discovered using the traditional morphology-based approaches. In this review, we explore the existing literature and most recent findings surrounding structure, functioning, and ecology of root-fungal symbiosis, which highlight the fact that plant fitness can be altered by taxonomically/ecologically diverse fungal symbionts regardless of root colonization and interface specialization. Furthermore, transition from saprotrophy to biotrophy seems to be a common event that occurs in diverse fungal lineages (consisting of root endophytes, soil saprotrophs, wood decayers etc.), and which may be accompanied by development of specialized interface structures and/or mycorrhiza-like effects on plant growth and nutrition.

RevDate: 2018-12-11

Koné NA, Soro B, Vanié-Léabo LPL, et al (2018)

Diversity, phenology and distribution of Termitomyces species in Côte d'Ivoire.

Mycology, 9(4):307-315 pii:1500498.

The mutualistic symbiosis between termites of the Macrotermitinae subfamily (Isoptera: Termitidae) and fungi of the genus Termitomyces (Basidiomycota: Lyophyllaceae) is of great ecological and socio-economic importance. Seasonal fruit bodies of the symbiotic fungi are regularly collected and sold in Côte d'Ivoire. However, there are very few studies on their diversity, phenology, distribution and especially the socio-economic scope of the fruit bodies of these fungi at a national scale. This study aims at (i) assessing the diversity of Termitomyces fruit bodies in Côte d'Ivoire and (ii) mapping their fructification areas through a determination of their spatiotemporal distribution according to a climatic and phytogeographic gradients. Using ethnomycological surveys all over the Ivorian territory, information was collected from rural populations on the fructification of Termitomyces and their socio-economic importance. Based on these surveys, sampling efforts of these fungi were properly structured and oriented. The results revealed a diversity of 16 species of Termitomyces, including 9 species new to Côte d'Ivoire and 2 probably new to science. Five species were found in the forest zone, nine in theGuinean savannah zone and four in the Sudano-Guinean zone. Termitomyces's fructifications were observed throughout the year, with specific period for each species. All listed species are regularly consumed by populations. However, only Termitomyces letestui (Pat.) R. Heim and Termitomyces schimperi (Pat.) R. Heim are marketed on a relatively large scale.

RevDate: 2018-12-11

Newman-Griffis AH, Del Cerro P, Charpentier M, et al (2018)

Medicago LINC complexes function in nuclear morphology, nuclear movement, and root nodule symbiosis.

Plant physiology pii:pp.18.01111 [Epub ahead of print].

Nuclear movement is involved in cellular and developmental processes across eukaryotic life, often driven by Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes, which bridge the nuclear envelope (NE) via the interaction of Klarsicht/ANC-1/Syne-1 Homology (KASH) and Sad1/UNC-84 (SUN) proteins. Arabidopsis (Arabidopsis thaliana) LINC complexes are involved in nuclear movement and positioning in several cell types. Observations since the 1950s have described targeted nuclear movement and positioning during symbiosis initiation between legumes and rhizobia, but it has never been established whether these movements are functional or incidental. Here, we identify and characterize LINC complexes in the model legume Medicago truncatula. We show that LINC complex characteristics such as NE localization, dependence of KASH proteins on SUN protein binding for NE enrichment, and direct SUN-KASH binding are conserved between plant species. Using a SUN dominant-negative strategy, we demonstrate that LINC complexes are necessary for proper nuclear shaping and movement in Medicago root hairs, and are important for infection thread initiation and nodulation.

RevDate: 2018-12-11

Hu D, Baskin JM, Baskin CC, et al (2018)

Arbuscular mycorrhizal symbiosis and achene mucilage have independent functions in seedling growth of a desert shrub.

Journal of plant physiology, 232:1-11 pii:S0176-1617(18)30556-X [Epub ahead of print].

Arbuscular mycorrhizal (AM) symbiosis can play a role in improving seedling establishment in deserts, and it has been suggested that achene mucilage facilitates seedling establishment in sandy deserts and that mucilage biodegradation products may improve seedling growth. We aimed to determine if AM symbiosis interacts with achene mucilage in regulating seedling growth in sand dunes. Up to 20 A M fungal taxa colonized Artemisia sphaerocephala roots in the field, and mycorrhizal frequency and colonization intensity exhibited seasonal dynamics. In the greenhouse, total biomass of AM fungal-colonized plants decreased, whereas the root/shoot ratio increased. AM symbiosis resulted in increased concentrations of nutrients and chlorophyll and decreased concentrations of salicylic acid (SA) and abscisic acid (ABA). Achene mucilage had a weaker effect on biomass and on nutrient, chlorophyll, and phytohormone concentration than did AM symbiosis. We suggest that AM symbiosis and achene mucilage act independently in enhancing seedling establishment in sandy deserts.

RevDate: 2018-12-11

Hanachi M, Manichanh C, Schoenenberger A, et al (2018)

Altered host-gut microbes symbiosis in severely malnourished anorexia nervosa (AN) patients undergoing enteral nutrition: An explicative factor of functional intestinal disorders?.

Clinical nutrition (Edinburgh, Scotland) pii:S0261-5614(18)32474-9 [Epub ahead of print].

BACKGROUND: Functional intestinal disorders (FIDs) are frequently observed in patients with anorexia nervosa (AN). Relationship between FIDs and a potential gut microbiota dysbiosis has been poorly explored.

OBJECTIVE: We aimed to determine an association between FIDs severity and dysbiosis of the intestinal microbiota in a severely malnourished patient population with AN undergoing enteral nutrition.

DESIGN: Faecal microbiota of AN (DSM IVr criteria) female inpatients were collected and compared to healthy controls based on 16S rRNA profiling. The severity of FIDs was evaluated in patients and healthy controls using Francis Score.

RESULTS: Thirty-three patients (BMI: 11,7 ± 1,5; Age: 32 ± 12) and 22 healthy controls (BMI: 21 ± 2; age: 36 ± 12) were included. A marked dysbiosis was identified in AN patients compared to healthy controls (p = 0.03). Some potentially pathogenic bacterial genera (Klebsiella, Salmonella) were more abundant in AN patients whereas, other bacterial symbionts (Eubacterium and Roseburia) involved in immune balance were significantly less abundant in patients than controls. Severity of FIDs was strongly correlated with several microbial genera (r = -0.581 for an unknown genus belonging to Peptostreptococcaceae family; r = 0.392 for Dialister, r = 0.444 for Robinsoniella and r = 0.488 for Enterococcus). Other associations between dysbiosis, clinical and biological characteristics were identified including severity of undernutrition (BMI).

CONCLUSION: Observed gut microbiota dysbiosis in malnourished patients with anorexia nervosa is correlated with the severity of FIDs and other metabolic disturbances, which strongly suggests an altered host-microbe symbiosis.

RevDate: 2018-12-04

Barelli L, Moreira CC, MJ Bidochka (2018)

Initial stages of endophytic colonization by Metarhizium involves rhizoplane colonization.

Microbiology (Reading, England), 164(12):1531-1540.

Here we assessed the time course of rhizoplane colonization by the endophytic insect pathogenic fungus Metarhizium robertsii. We describe a method of quantifying root colonization of bean plants by M. robertsii using quantitative polymerase chain reaction (qPCR). Results of this method were compared to the standard plate count method using colony-forming units (c.f.u.). Both the c.f.u. and qPCR methods were used to monitor the time-course of haricot bean (Phaseolus vulgaris) colonization by a strain of M. robertsii that expresses the green fluorescent protein (ARSEF 2575-GFP) for colony verification. There was a strong correlation between the results of the c.f.u. and qPCR methods, indicating that both methods are well suited for the determination of colonization of P. vulgaris roots by M. robertsii. Primers for a catalase gene (cat) amplified DNA from M. robertsii, M. brunneum and M. guizhouense. Primers for a nitrogen response-regulator (nrr) additionally detected M. acridum and M. flavoviride, whereas Metarhizium perilipin-like protein (mpl) primers were specific to M. robertsii alone. However, cat was the only target that specifically amplified Metarhizium in experiments utilizing non-sterile soil. Endophytic colonization of P. vulgaris at 60 days post-inoculation with M. robertsii was detected from surface-sterilized roots with more sensitivity using our qPCR technique over the c.f.u. method. Our results suggest that there is a prolonged period of rhizoplane colonization by Metarhizium with transient, low-level endophytic colonization of the root system of P. vulgaris that persists for the entirety of the plant life cycle.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Inagaki T, K Matsuura (2018)

Extended mutualism between termites and gut microbes: nutritional symbionts contribute to nest hygiene.

Die Naturwissenschaften, 105(9-10):52.

All higher eukaryotes have established symbiotic relationships with diverse microorganisms. One of the most well-characterized symbiotic systems is that of termites and their intestinal microorganisms, which digest cellulose. Recently, diverse types of symbioses between gut microbes and host organisms including humans have received growing attention for various features of their complex interactions beyond nutrition. In termites, researchers are beginning to explore such function of gut symbionts, but only the contribution to internal immunity against entomopathogen is known in a few species. Here, we report that gut symbionts of the dampwood termite Zootermopsis nevadensis protect nests from the spread of the commensal bacterium Serratia marcescens, which has pathogenic potential. Defaunated termites dispersed S. marcescens in the surrounding environment by feeding on the bacteria, which then survived passage through their alimentary tracts, while non-defaunated termites did not. Loss of gut symbionts caused a significant reduction in intestinal acetate, which is an important carbon source for termites. Culture experiments showed that acetate had significant inhibitory effects on S. marcescens at a concentration as low as 12 mM, which indicated that the intestinal acetate of non-defaunated termites (40-130 mM) was capable of suppressing this bacterium. These results suggest that digestive derivatives produced by intestinal symbionts play an essential role in nest hygiene in addition to their nutritional function for termites. Our study provides a better understanding of the multifunctionality of symbiotic relationships in diverse organisms beyond nutrition.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Lei YJ, Tian Y, Zhang J, et al (2018)

Microalgae cultivation and nutrients removal from sewage sludge after ozonizing in algal-bacteria system.

Ecotoxicology and environmental safety, 165:107-114.

The feasibility of growing algae in concentrated wastewater generated from sludge ozonation for simultaneous nutrients removal and biomass production was studied. The effects of bacteria addition into microalgae on nutrients removal, biomass yield and settleability, the growth rate of algae and concentrations of extracellular polymeric substances (EPS) and soluble microbial products (SMP) were investigated. The results showed that the growth rate of algae in algal-bacteria system (0.2182) was improved than in algae-only system (0.1852), while both of them are comparable with others reported previously. And the addition of bacteria enhanced COD, NH4+-N, TN and TP removal rate by 23.9 ± 3.3%, 27.7 ± 3.6%, 16.6 ± 1.8% and 14.9 ± 2.2%, respectively. And 32.8 ± 0.7% of the TN and 50.3 ± 1.8% of the TP were recycled from ozonated sludge-supernatant (OSS) being absorbed into algal-bacterial biomass. The algal-bacteria system also demonstrated advantages on biomass settleability and heavy metals removal. Finally, the mechanism involving matter exchange and algal-bacteria system on OSS treatment in this study were discussed through evaluation of nutrients, SMP and EPS contents, nitrogen and phosphorus balance.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Kostaropoulos T, Papageorgiou L, Champeris Tsaniras S, et al (2018)

Carcinogenic Pesticide Control via Hijacking Endosymbiosis; The Paradigm of DSB-A from Wolbachia pipientis for the Management of Otiorhynchus singularis.

In vivo (Athens, Greece), 32(5):1051-1062.

BACKGROUND/AIM: Pesticides have little, if any specificity, to the pathogen they target in most cases. Wide spectrum toxic chemicals are being used to remove pestcides and salvage crops and economies linked to agriculture. The burden on the environment, public health and economy is huge. Traditional pestcide control is based on administering heavy loads of highly toxic compounds and elements that essentially strip all life from the field. Those chemicals are a leading cause of increased cancer related deaths in countryside. Herein, the Trojan horse of endosymbiosis was used, in an effort to control pests using high specificity compounds in reduced quantities.

MATERIALS AND METHODS: Our pipeline has been applied on the case of Otiorhynchus singularis, which is a very widespread pest, whose impact is devastating on a repertoire of crops. To date, there is no specific pesticide nor agent to control it. The deployed strategy involves the inhibition of the key DSB-A enzyme of its endosymbiotic Wolbachia pipientis bacterial strain.

RESULTS: Our methodology, provides the means to design, test and identify highly specific pestcide control substances that minimize the impact of toxic chemicals on health, economy and the environment.

CONCLUSION: All in all, in this study a radical computer-based pipeline is proposed that could be adopted under many other similar scenarios and pave the way for precision agriculture via optimized pest control.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Stabili L, Parisi MG, Parrinello D, et al (2018)

Cnidarian Interaction with Microbial Communities: From Aid to Animal's Health to Rejection Responses.

Marine drugs, 16(9):.

The phylum Cnidaria is an ancient branch in the tree of metazoans. Several species exert a remarkable longevity, suggesting the existence of a developed and consistent defense mechanism of the innate immunity capable to overcome the potential repeated exposure to microbial pathogenic agents. Increasing evidence indicates that the innate immune system in Cnidarians is not only involved in the disruption of harmful microorganisms, but also is crucial in structuring tissue-associated microbial communities that are essential components of the Cnidarian holobiont and useful to the animal's health for several functions, including metabolism, immune defense, development, and behavior. Sometimes, the shifts in the normal microbiota may be used as "early" bio-indicators of both environmental changes and/or animal disease. Here the Cnidarians relationships with microbial communities and the potential biotechnological applications are summarized and discussed.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Hinojosa-Vidal E, Marco F, Martínez-Alberola F, et al (2018)

Characterization of the responses to saline stress in the symbiotic green microalga Trebouxia sp. TR9.

Planta, 248(6):1473-1486.

MAIN CONCLUSION: For the first time we provide a study on the physiological, ultrastructural and molecular effects of salt stress on a terrestrial symbiotic green microalga, Trebouxia sp. TR9. Although tolerance to saline conditions has been thoroughly studied in plants and, to an extent, free-living microalgae, scientific data regarding salt stress on symbiotic lichen microalgae is scarce to non-existent. Since lichen phycobionts are capable of enduring harsh, restrictive and rapidly changing environments, it is interesting to study the metabolic machinery operating under these extreme conditions. We aim to determine the effects of prolonged exposure to high salt concentrations on the symbiotic phycobiont Trebouxia sp. TR9, isolated from the lichen Ramalina farinacea. Our results suggest that, when this alga is confronted with extreme saline conditions, the cellular structures are affected to an extent, with limited chlorophyll content loss and photosynthetic activity remaining after 72 h of exposure to 5 M NaCl. Furthermore, this organism displays a rather different molecular response compared to land plants and free-living halophile microalgae, with no noticeable increase in ABA levels and ABA-related gene expression until the external NaCl concentration is raised to 3 M NaCl. Despite this, the ABA transduction pathway seems functional, since the ABA-related genes tested are responsive to exogenous ABA. These observations could suggest that this symbiotic green alga may have developed alternative molecular pathways to cope with highly saline environments.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Kraberger S, Hofstetter RW, Potter KA, et al (2018)

Genomoviruses associated with mountain and western pine beetles.

Virus research, 256:17-20.

Genomoviruses are circular single-stranded DNA viruses (∼2 kb in size) classified into nine genera, they are highly diverse and have been identified in a variety of samples ranging from fungi to animal sera. Here we identify five genomoviruses belonging to the Gemycircularvirus genus and one to the Gemykibivirus genus from mountain pine beetle and western pine beetle sampled in Arizona. Collectively these six viral genomes share <77% genome-wide pairwise identity and hence represent six new species of genomoviruses. Four of the gemycircularviruses from the mountain pine beetles are recombinant, with one having a recombinant region that spans the entire capsid protein. Pine beetles have a symbiotic relationship with certain tree pathogenic fungi. Therefore given that Sclerotinia sclerotiorum hypovirulence-associated DNA virus 1, a gemycircularvirus, induces hypovirulence in the plant pathogenic fungus Sclerotinia sclerotiorum and infects the mycophagous insect Lycoriella ingenua, it is possible that the six genomoviruses identified here may be directly associated with the pine beetle fungal symbionts and/or with the insects themselves.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Kurečič M, Rijavec T, Hribernik S, et al (2018)

Novel electrospun fibers with incorporated commensal bacteria for potential preventive treatment of the diabetic foot.

Nanomedicine (London, England), 13(13):1583-1594.

AIM: A novel electrospun biocompatible nanofibrous material loaded with commensal bacteria for potential preventive treatment of the diabetic foot was developed.

MATERIALS & METHODS: Two biocompatible polymers (carboxymethylcellulose and polyethylene oxide) were combined with a bacterium isolate from the skin located between the toes of a healthy adult (identified using a matrix-assisted laser desorption/ionization mass spectrometry-based method as a strain of Staphylococcus epidermidis). Higher bacteria loads in the material were assured through their encapsulation in polyethylenimine. The nanofibrous material was characterized using scanning electron microscopy, zeta-potential measurements and through evaluation of cell growth and viability.

RESULTS & DISCUSSION: nanometer formation was confirmed using scanning electron microscopy, while the zeta-potential measurements revealed successful bacteria encapsulation. Viable and sufficiently growing cells were confirmed prior and after their incorporation.

CONCLUSION: The prepared materials were proven suitable to deliver viable commensal bacteria in a comparable share to the Staphylococcaceae in the foot microbiome making this approach promising for preventive diabetic foot treatment.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Xu L, Zhang Y, Zhang S, et al (2018)

Comparative analysis of the immune system of an invasive bark beetle, Dendroctonus valens, infected by an entomopathogenic fungus.

Developmental and comparative immunology, 88:65-69.

Dendroctonus valens LeConte is one of the most economically important forest pest in China. Leptographium procerum, a mutualistic fungus can assist the host beetle in overcoming the pine's chemical defenses, and Beauveria bassiana, an entomopathogenic fungus has shown high beetle killing efficiency. Considering that the D. valens immune system remains unknown at the genomic level, a mutualistic and antagonistic fungus associated with the beetle provides an ideal model for studying immune interactions between the insect and associated fungi. Here, B. bassiana killed most tested larvae more effectively than L. procerum and Tween. The entomopathogenic fungus provoked stronger responses than the symbiotic fungus at the transcriptome level. We identified 185 immunity-related genes, including pattern recognition receptors, signal modulators, members of immune pathways (Toll, IMD, and JAK/STAT), and immune effectors. Quantitative real-time PCR analysis confirmed that several recognition receptors and effector genes were activated at 1 or 2 days post infection, while the effector genes were suppressed at 4 days post infection by B. bassiana, respectively. In contrast, effector genes were upregulated in response to L. procerum. Together, this study provides a comprehensive sequence resource and insight into the D. valens immune system and lays a basis for understanding the molecular aspects of the interaction between the host and associated fungi.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Vet S, de Buyl S, Faust K, et al (2018)

Bistability in a system of two species interacting through mutualism as well as competition: Chemostat vs. Lotka-Volterra equations.

PloS one, 13(6):e0197462.

We theoretically study the dynamics of two interacting microbial species in the chemostat. These species are competitors for a common resource, as well as mutualists due to cross-feeding. In line with previous studies (Assaneo, et al., 2013; Holland, et al., 2010; Iwata, et al., 2011), we demonstrate that this system has a rich repertoire of dynamical behavior, including bistability. Standard Lotka-Volterra equations are not capable to describe this particular system, as these account for only one type of interaction (mutualistic or competitive). We show here that the different steady state solutions can be well captured by an extended Lotka-Volterra model, which better describe the density-dependent interaction (mutualism at low density and competition at high density). This two-variable model provides a more intuitive description of the dynamical behavior than the chemostat equations.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Houles A, Vincent B, David M, et al (2018)

Ectomycorrhizal Communities Associated with the Legume Acacia spirorbis Growing on Contrasted Edaphic Constraints in New Caledonia.

Microbial ecology, 76(4):964-975.

This study aims to characterize the ectomycorrhizal (ECM) communities associated with Acacia spirorbis, a legume tree widely spread in New Caledonia that spontaneously grows on contrasted edaphic constraints, i.e. calcareous, ferralitic and volcano-sedimentary soils. Soil geochemical parameters and diversity of ECM communities were assessed in 12 sites representative of the three mains categories of soils. The ectomycorrhizal status of Acacia spirorbis was confirmed in all studied soils, with a fungal community dominated at 92% by Basidiomycota, mostly represented by/tomentella-thelephora (27.6%), /boletus (15.8%), /sebacina (10.5%), /russula-lactarius (10.5%) and /pisolithus-scleroderma (7.9%) lineages. The diversity and the proportion of the ECM lineages were similar for the ferralitic and volcano-sedimentary soils but significantly different for the calcareous soils. These differences in the distribution of the ECM communities were statistically correlated with pH, Ca, P and Al in the calcareous soils and with Co in the ferralitic soils. Altogether, these data suggest a high capacity of A. spirorbis to form ECM symbioses with a large spectrum of fungi regardless the soil categories with contrasted edaphic parameters.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Saucedo-Carabez JR, Ploetz RC, Konkol JL, et al (2018)

Partnerships Between Ambrosia Beetles and Fungi: Lineage-Specific Promiscuity Among Vectors of the Laurel Wilt Pathogen, Raffaelea lauricola.

Microbial ecology, 76(4):925-940.

Nutritional mutualisms that ambrosia beetles have with fungi are poorly understood. Although these interactions were initially thought to be specific associations with a primary symbiont, there is increasing evidence that some of these fungi are associated with, and move among, multiple beetle partners. We examined culturable fungi recovered from mycangia of ambrosia beetles associated with trees of Persea humilis (silk bay, one site) and P. americana (avocado, six commercial orchards) that were affected by laurel wilt, an invasive disease caused by a symbiont, Raffaelea lauricola, of an Asian ambrosia beetle, Xyleborus glabratus. Fungi were isolated from 20 adult females of X. glabratus from silk bay and 70 each of Xyleborus affinis, Xyleborus bispinatus, Xyleborus volvulus, Xyleborinus saxesenii, and Xylosandrus crassiusculus from avocado. With partial sequences of ribosomal (LSU and SSU) and nuclear (β-tubulin) genes, one to several operational taxonomic units (OTUs) of fungi were identified in assayed individuals. Distinct populations of fungi were recovered from each of the examined beetle species. Raffaelea lauricola was present in all beetles except X. saxesenii and X. crassiusculus, and Raffaelea spp. predominated in Xyleborus spp. Raffaelea arxii, R. subalba, and R. subfusca were present in more than a single species of Xyleborus, and R. arxii was the most abundant symbiont in both X. affinis and X. volvulus. Raffaelea aguacate was detected for the first time in an ambrosia beetle (X. bispinatus). Yeasts (Ascomycota, Saccharomycotina) were found consistently in the mycangia of the examined beetles, and distinct, putatively co-adapted populations of these fungi were associated with each beetle species. Greater understandings are needed for how mycangia in ambrosia beetles interact with fungi, including yeasts which play currently underresearched roles in these insects.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Birnbaum C, Bissett A, Teste FP, et al (2018)

Symbiotic N2-Fixer Community Composition, but Not Diversity, Shifts in Nodules of a Single Host Legume Across a 2-Million-Year Dune Chronosequence.

Microbial ecology, 76(4):1009-1020.

Long-term soil age gradients are useful model systems to study how changes in nutrient limitation shape communities of plant root mutualists because they represent strong natural gradients of nutrient availability, particularly of nitrogen (N) and phosphorus (P). Here, we investigated changes in the dinitrogen (N2)-fixing bacterial community composition and diversity in nodules of a single host legume (Acacia rostellifera) across the Jurien Bay chronosequence, a retrogressive 2 million-year-old sequence of coastal dunes representing an exceptionally strong natural soil fertility gradient. We collected nodules from plants grown in soils from five chronosequence stages ranging from very young (10s of years; associated with strong N limitation for plant growth) to very old (> 2,000,000 years; associated with strong P limitation), and sequenced the nifH gene in root nodules to determine the composition and diversity of N2-fixing bacterial symbionts. A total of 335 unique nifH gene operational taxonomic units (OTUs) were identified. Community composition of N2-fixing bacteria within nodules, but not diversity, changed with increasing soil age. These changes were attributed to pedogenesis-driven shifts in edaphic conditions, specifically pH, exchangeable manganese, resin-extractable phosphate, nitrate and nitrification rate. A large number of common N2-fixing bacteria genera (e.g. Bradyrhizobium, Ensifer, Mesorhizobium and Rhizobium) belonging to the Rhizobiaceae family (α-proteobacteria) comprised 70% of all raw sequences and were present in all nodules. However, the oldest soils, which show some of the lowest soil P availability ever recorded, harboured the largest proportion of unclassified OTUs, suggesting a unique set of N2-fixing bacteria adapted to extreme P limitation. Our results show that N2-fixing bacterial composition varies strongly during long-term ecosystem development, even within the same host, and therefore rhizobia show strong edaphic preferences.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Li L, Mohamad OAA, Ma J, et al (2018)

Synergistic plant-microbe interactions between endophytic bacterial communities and the medicinal plant Glycyrrhiza uralensis F.

Antonie van Leeuwenhoek, 111(10):1735-1748.

Little is known about the composition, diversity, and geographical distribution of bacterial communities associated with medicinal plants in arid lands. To address this, a collection of 116 endophytic bacteria were isolated from wild populations of the herb Glycyrrhiza uralensis Fisch (licorice) in Xinyuan, Gongliu, and Tekesi of Xinjiang Province, China, and identified based on their 16S rRNA gene sequences. The endophytes were highly diverse, including 20 genera and 35 species. The number of distinct bacterial genera obtained from root tissues was higher (n = 14) compared to stem (n = 9) and leaf (n = 6) tissue. Geographically, the diversity of culturable endophytic genera was higher at the Tekesi (n = 14) and Xinyuan (n = 12) sites than the Gongliu site (n = 4), reflecting the extremely low organic carbon content, high salinity, and low nutrient status of Gongliu soils. The endophytic bacteria exhibited a number of plant growth-promoting activities ex situ, including diazotrophy, phosphate and potassium solubilization, siderophore production, auxin synthesis, and production of hydrolytic enzymes. Twelve endophytes were selected based on their ex situ plant growth-promoting activities for growth chamber assays to test for their ability to promote growth of G. uralensis F. and Triticum aestivum (wheat) plants. Several strains belonging to the genera Bacillus (n = 6) and Achromobacter (n = 1) stimulated total biomass production in both G. uralensis and T. aestivum under low-nutrient conditions. This work is the first report on the isolation and characterization of endophytes associated with G. uralensis F. in arid lands. The results demonstrate the broad diversity of endophytes associated with wild licorice and suggest that some Bacillus strains may be promising candidates for biofertilizers to promote enhanced survival and growth of licorice and other valuable crops in arid environments.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Horká I, De Grave S, Fransen CHJM, et al (2018)

Multiple origins and strong phenotypic convergence in fish-cleaning palaemonid shrimp lineages.

Molecular phylogenetics and evolution, 124:71-81.

Several species of palaemonid shrimps are known to act as fish-cleaning symbionts, with cleaning interactions ranging from dedicated (obligate) to facultative. We confirmed five evolutionarily independent origins of fish cleaning symbioses within the family Palaemonidae based on a phylogenetic analysis and the ancestral state reconstruction of 68 species, including 13 fish-cleaners from the genera Ancylomenes, Brachycarpus, Palaemon, Periclimenes, and Urocaridella. We focus in particular on two distantly related lineages of fish cleaning shrimps with allopatric distributions, the Indo-West Pacific Ancylomenes and the western Atlantic monophyletic Ancylomenes/Periclimenes group, which exhibit striking similarities in morphology, colouration and complex behaviour. Specifically, representatives of both lineages are similar in: (1) the general body shape and colour pattern; (2) the utilization of sea anemones as conspicuous cleaning stations; and (3) the use of sideways body swaying to visually promote their bright colour spots in order to attract fish clients. Such morphological, ecological and ethological convergences are apparently due to adaptations to fish cleaning linked to the establishment of similar modes of communication with fish clients in these species.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Volland JM, Schintlmeister A, Zambalos H, et al (2018)

NanoSIMS and tissue autoradiography reveal symbiont carbon fixation and organic carbon transfer to giant ciliate host.

The ISME journal, 12(3):714-727.

The giant colonial ciliate Zoothamnium niveum harbors a monolayer of the gammaproteobacteria Cand. Thiobios zoothamnicoli on its outer surface. Cultivation experiments revealed maximal growth and survival under steady flow of high oxygen and low sulfide concentrations. We aimed at directly demonstrating the sulfur-oxidizing, chemoautotrophic nature of the symbionts and at investigating putative carbon transfer from the symbiont to the ciliate host. We performed pulse-chase incubations with 14C- and 13C-labeled bicarbonate under varying environmental conditions. A combination of tissue autoradiography and nanoscale secondary ion mass spectrometry coupled with transmission electron microscopy was used to follow the fate of the radioactive and stable isotopes of carbon, respectively. We show that symbiont cells fix substantial amounts of inorganic carbon in the presence of sulfide, but also (to a lesser degree) in the absence of sulfide by utilizing internally stored sulfur. Isotope labeling patterns point to translocation of organic carbon to the host through both release of these compounds and digestion of symbiont cells. The latter mechanism is also supported by ultracytochemical detection of acid phosphatase in lysosomes and in food vacuoles of ciliate cells. Fluorescence in situ hybridization of freshly collected ciliates revealed that the vast majority of ingested microbial cells were ectosymbionts.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Guidolin AS, Cataldi TR, Labate CA, et al (2018)

Spiroplasma affects host aphid proteomics feeding on two nutritional resources.

Scientific reports, 8(1):2466.

Bacterial symbionts are broadly distributed among insects, influencing their bioecology to different degrees. Aphids carry a number of secondary symbionts that can influence aphid physiology and fitness attributes. Spiroplasma is seldom reported as an aphid symbiont, but a high level of infection has been observed in one population of the tropical aphid Aphis citricidus. We used sister isolines of Spiroplasma-infected (Ac-BS) and Spiroplasma-free (Ac-B) aphids reared on sweet orange (optimum host) and orange jasmine (suboptimum host) to demonstrate the effects of Spiroplasma infection in the aphid proteome profile. A higher number of proteins were differently abundant in aphids feeding on orange jasmine, indicating an impact of host plant quality. In both host plants, the majority of proteins affected by Spiroplasma infection were heat shock proteins, proteins linked to cell function and structure, and energy metabolism. Spiroplasma also induced changes in proteins involved in antimicrobial activity, carbohydrate processing and metabolism, amino acid synthesis and metabolism in aphids feeding on orange jasmine. We discuss on how the aphid host proteome is differentially affected by Spiroplasma infection when the host is exploiting host plants with different nutritional values.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Massé A, Domart-Coulon I, Golubic S, et al (2018)

Early skeletal colonization of the coral holobiont by the microboring Ulvophyceae Ostreobium sp.

Scientific reports, 8(1):2293.

Ostreobium sp. (Bryopsidales, Ulvophyceae) is a major microboring alga involved in tropical reef dissolution, with a proposed symbiotic lifestyle in living corals. However, its diversity and colonization dynamics in host's early life stages remained unknown. Here, we mapped microborer distribution and abundance in skeletons of the branching coral Pocillopora damicornis from the onset of calcification in primary polyps (7 days) to budding juvenile colonies (1 and 3 months) growing on carbonate and non-carbonate substrates pre-colonized by natural biofilms, and compared them to adult colonies (in aquarium settings). Primary polyps were surprisingly already colonized by microboring filaments and their level of invasion depended on the nature of settlement substrate and the extent of its pre-colonization by microborers. Growth of early coral recruits was unaffected even when microborers were in close vicinity to the polyp tissue. In addition to morphotype observations, chloroplast-encoded rbcL gene sequence analyses revealed nine new Ostreobium clades (OTU99%) in Pocillopora coral. Recruits and adults shared one dominant rbcL clade, undetected in larvae, but also present in aquarium seawater, carbonate and non-carbonate settlement substrates, and in corals from reef settings. Our results show a substratum-dependent colonization by Ostreobium clades, and indicate horizontal transmission of Ostreobium-coral associations.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Watanabe S, Yoshimura J, E Hasegawa (2018)

Ants improve the reproduction of inferior morphs to maintain a polymorphism in symbiont aphids.

Scientific reports, 8(1):2313.

Identifying stable polymorphisms is essential for understanding biodiversity. Distinctive polymorphisms are rare in nature because a superior morph should dominate a population. In addition to the three known mechanisms for polymorphism persistence, we recently reported a fourth mechanism: protection of the polymorphism by symbionts. Attending ants preferentially protect polymorphic aphid colonies consisting of green and red morphs. Here, we show that attending ants manipulate the reproductive rate of their preferred green morphs to equal that of the red morphs, leading to the persistence of the polymorphism within the colonies. We could not, however, explain how the ants maintained the polymorphism in aphid colonies regardless of inter-morph competition. Manipulation by symbionts may be important for the maintenance of polymorphisms and the resulting biodiversity in certain symbiotic systems.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Wang B, Lu M, Cook JM, et al (2018)

Chemical camouflage: a key process in shaping an ant-treehopper and fig-fig wasp mutualistic network.

Scientific reports, 8(1):1833.

Different types of mutualisms may interact, co-evolve and form complex networks of interdependences, but how species interact in networks of a mutualistic community and maintain its stability remains unclear. In a mutualistic network between treehoppers-weaver ants and fig-pollinating wasps, we found that the cuticular hydrocarbons of the treehoppers are more similar to the surface chemical profiles of fig inflorescence branches (FIB) than the cuticular hydrocarbons of the fig wasps. Behavioral assays showed that the cuticular hydrocarbons from both treehoppers and FIBs reduce the propensity of weaver ants to attack treehoppers even in the absence of honeydew rewards, suggesting that chemical camouflage helps enforce the mutualism between weaver ants and treehoppers. High levels of weaver ant and treehopper abundances help maintain the dominance of pollinating fig wasps in the fig wasp community and also increase fig seed production, as a result of discriminative predation and disturbance by weaver ants of ovipositing non-pollinating fig wasps (NPFWs). Ants therefore help preserve this fig-pollinating wasp mutualism from over exploitation by NPFWs. Our results imply that in this mutualistic network chemical camouflage plays a decisive role in regulating the behavior of a key species and indirectly shaping the architecture of complex arthropod-plant interactions.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Mohamed AR, Cumbo VR, Harii S, et al (2018)

Deciphering the nature of the coral-Chromera association.

The ISME journal, 12(3):776-790.

Since the discovery of Chromera velia as a novel coral-associated microalga, this organism has attracted interest because of its unique evolutionary position between the photosynthetic dinoflagellates and the parasitic apicomplexans. The nature of the relationship between Chromera and its coral host is controversial. Is it a mutualism, from which both participants benefit, a parasitic relationship, or a chance association? To better understand the interaction, larvae of the common Indo-Pacific reef-building coral Acropora digitifera were experimentally infected with Chromera, and the impact on the host transcriptome was assessed at 4, 12, and 48 h post-infection using Illumina RNA-Seq technology. The transcriptomic response of the coral to Chromera was complex and implies that host immunity is strongly suppressed, and both phagosome maturation and the apoptotic machinery is modified. These responses differ markedly from those described for infection with a competent strain of the coral mutualist Symbiodinium, instead resembling those of vertebrate hosts to parasites and/or pathogens such as Mycobacterium tuberculosis. Consistent with ecological studies suggesting that the association may be accidental, the transcriptional response of A. digitifera larvae leads us to conclude that Chromera could be a coral parasite, commensal, or accidental bystander, but certainly not a beneficial mutualist.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Harris HMB, Bourin MJB, Claesson MJ, et al (2017)

Phylogenomics and comparative genomics of Lactobacillus salivarius, a mammalian gut commensal.

Microbial genomics, 3(8):e000115.

The genus Lactobacillus is a diverse group with a combined species count of over 200. They are the largest group within the lactic acid bacteria and one of the most important bacterial groups involved in food microbiology and human nutrition because of their fermentative and probiotic properties. Lactobacillus salivarius, a species commonly isolated from the gastrointestinal tract of humans and animals, has been described as having potential probiotic properties and results of previous studies have revealed considerable functional diversity existing on both the chromosomes and plasmids. Our study consists of comparative genomic analyses of the functional and phylogenomic diversity of 42 genomes of strains of L. salivarius using bioinformatic techniques. The main aim of the study was to describe intra-species diversity and to determine how this diversity is spread across the replicons. We found that multiple phylogenomic and non-phylogenomic methods used for reconstructing trees all converge on similar tree topologies, showing that different metrics largely agree on the evolutionary history of the species. The greatest genomic variation lies on the small plasmids, followed by the repA-type circular megaplasmid, with the chromosome varying least of all. Additionally, the presence of extra linear and circular megaplasmids is noted in several strains, while small plasmids are not always present. Glycosyl hydrolases, bacteriocins and proteases vary considerably on all replicons while two exopolysaccharide clusters and several clustered regularly interspaced short palindromic repeats-associated systems show a lot of variation on the chromosome. Overall, despite its reputation as a mammalian gastrointestinal tract specialist, the intra-specific variation of L. salivarius reveals potential strain-dependant effects on human health.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Kuhn KA, Schulz HM, Regner EH, et al (2018)

Bacteroidales recruit IL-6-producing intraepithelial lymphocytes in the colon to promote barrier integrity.

Mucosal immunology, 11(2):357-368.

Interactions between the microbiota and distal gut are important for the maintenance of a healthy intestinal barrier; dysbiosis of intestinal microbial communities has emerged as a likely contributor to diseases that arise at the level of the mucosa. Intraepithelial lymphocytes (IELs) are positioned within the epithelial barrier, and in the small intestine they function to maintain epithelial homeostasis. We hypothesized that colon IELs promote epithelial barrier function through the expression of cytokines in response to interactions with commensal bacteria. Profiling of bacterial 16S ribosomal RNA revealed that candidate bacteria in the order Bacteroidales are sufficient to promote IEL presence in the colon that in turn produce interleukin-6 (IL-6) in a MyD88 (myeloid differentiation primary response 88)-dependent manner. IEL-derived IL-6 is functionally important in the maintenance of the epithelial barrier as IL-6-/- mice were noted to have increased paracellular permeability, decreased claudin-1 expression, and a thinner mucus gel layer, all of which were reversed by transfer of IL-6+/+ IELs, leading to protection of mice in response to Citrobacter rodentium infection. Therefore, we conclude that microbiota provide a homeostatic role for epithelial barrier function through regulation of IEL-derived IL-6.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Lee KR, Wakeel A, Chakraborty P, et al (2018)

Cell Labeling with Magneto-Endosymbionts and the Dissection of the Subcellular Location, Fate, and Host Cell Interactions.

Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging, 20(1):55-64.

PURPOSE: The purposes of this study are to characterize magneto-endosymbiont (ME) labeling of mammalian cells and to discern the subcellular fate of these living contrast agents. MEs are novel magnetic resonance imaging (MRI) contrast agents that are being used for cell tracking studies. Understanding the fate of MEs in host cells is valuable for designing in vivo cell tracking experiments.

PROCEDURES: The ME's surface epitopes, contrast-producing paramagnetic magnetosomal iron, and genome were studied using immunocytochemistry (ICC), Fe and MRI contrast measurements, and quantitative polymerase chain reaction (qPCR), respectively. These assays, coupled with other common assays, enabled validation of ME cell labeling and dissection of ME subcellular processing.

RESULTS: The assays mentioned above provide qualitative and quantitative assessments of cell labeling, the subcellular localization and the fate of MEs. ICC results, with an ME-specific antibody, qualitatively shows homogenous labeling with MEs. The ferrozine assay shows that MEs have an average of 7 fg Fe/ME, ∼30 % of which contributes to MRI contrast and ME-labeled MDA-MB-231 (MDA-231) cells generally have 2.4 pg Fe/cell, implying ∼350 MEs/cell. Adjusting the concentration of Fe in the ME growth media reduces the concentration of non-MRI contrast-producing Fe. Results from the qPCR assay, which quantifies ME genomes in labeled cells, shows that processing of MEs begins within 24 h in MDA-231 cells. ICC results suggest this intracellular digestion of MEs occurs by the lysosomal degradation pathway. MEs coated with listeriolysin O (LLO) are able to escape the primary phagosome, but subsequently co-localize with LC3, an autophagy-associated molecule, and are processed for digestion. In embryos, where autophagy is transiently suppressed, MEs show an increased capacity for survival and even replication. Finally, transmission electron microscopy (TEM) of ME-labeled MDA-231 cells confirms that the magnetosomes (the MRI contrast-producing particles) remain intact and enable in vivo cell tracking.

CONCLUSIONS: MEs are used to label mammalian cells for the purpose of cell tracking in vivo, with MRI. Various assays described herein (ICC, ferrozine, and qPCR) allow qualitative and quantitative assessments of labeling efficiency and provide a detailed understanding of subcellular processing of MEs. In some cell types, MEs are digested, but the MRI-producing particles remain. Coating with LLO allows MEs to escape the primary phagosome, enhances retention slightly, and confirms that MEs are ultimately processed by autophagy. Numerous intracellular bacteria and all endosymbiotically derived organelles have evolved molecular mechanisms to avoid intracellular clearance, and identification of the specific processes involved in ME clearance provides a framework on which to develop MEs with enhanced retention in mammalian cells.

RevDate: 2018-12-11
CmpDate: 2018-12-11

Brewer KD, Spitler R, Lee KR, et al (2018)

Characterization of Magneto-Endosymbionts as MRI Cell Labeling and Tracking Agents.

Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging, 20(1):65-73.

PURPOSE: Magneto-endosymbionts (MEs) show promise as living magnetic resonance imaging (MRI) contrast agents for in vivo cell tracking. Here we characterize the biomedical imaging properties of ME contrast agents, in vitro and in vivo.

PROCEDURES: By adapting and engineering magnetotactic bacteria to the intracellular niche, we are creating magneto-endosymbionts (MEs) that offer advantages relative to passive iron-based contrast agents (superparamagnetic iron oxides, SPIOs) for cell tracking. This work presents a biomedical imaging characterization of MEs including: MRI transverse relaxivity (r 2) for MEs and ME-labeled cells (compared to a commercially available iron oxide nanoparticle); microscopic validation of labeling efficiency and subcellular locations; and in vivo imaging of a MDA-MB-231BR (231BR) human breast cancer cells in a mouse brain.

RESULTS: At 7T, r 2 relaxivity of bare MEs was higher (250 s-1 mM-1) than that of conventional SPIO (178 s-1 mM-1). Optimized in vitro loading of MEs into 231BR cells yielded 1-4 pg iron/cell (compared to 5-10 pg iron/cell for conventional SPIO). r 2 relaxivity dropped by a factor of ~3 upon loading into cells, and was on the same order of magnitude for ME-loaded cells compared to SPIO-loaded cells. In vivo, ME-labeled cells exhibited strong MR contrast, allowing as few as 100 cells to be detected in mice using an optimized 3D SPGR gradient-echo sequence.

CONCLUSIONS: Our results demonstrate the potential of magneto-endosymbionts as living MR contrast agents. They have r 2 relaxivity values comparable to traditional iron oxide nanoparticle contrast agents, and provide strong MR contrast when loaded into cells and implanted in tissue.

RevDate: 2018-12-06

Vernocchi P, Del Chierico F, Russo A, et al (2018)

Gut microbiota signatures in cystic fibrosis: Loss of host CFTR function drives the microbiota enterophenotype.

PloS one, 13(12):e0208171 pii:PONE-D-17-43072.

BACKGROUND: Cystic fibrosis (CF) is a disorder affecting the respiratory, digestive, reproductive systems and sweat glands. This lethal hereditary disease has known or suspected links to the dysbiosis gut microbiota. High-throughput meta-omics-based approaches may assist in unveiling this complex network of symbiosis modifications.

OBJECTIVES: The aim of this study was to provide a predictive and functional model of the gut microbiota enterophenotype of pediatric patients affected by CF under clinical stability.

METHODS: Thirty-one fecal samples were collected from CF patients and healthy children (HC) (age range, 1-6 years) and analysed using targeted-metagenomics and metabolomics to characterize the ecology and metabolism of CF-linked gut microbiota. The multidimensional data were low fused and processed by chemometric classification analysis.

RESULTS: The fused metagenomics and metabolomics based gut microbiota profile was characterized by a high abundance of Propionibacterium, Staphylococcus and Clostridiaceae, including Clostridium difficile, and a low abundance of Eggerthella, Eubacterium, Ruminococcus, Dorea, Faecalibacterium prausnitzii, and Lachnospiraceae, associated with overexpression of 4-aminobutyrate (GABA), choline, ethanol, propylbutyrate, and pyridine and low levels of sarcosine, 4-methylphenol, uracil, glucose, acetate, phenol, benzaldehyde, and methylacetate. The CF gut microbiota pattern revealed an enterophenotype intrinsically linked to disease, regardless of age, and with dysbiosis uninduced by reduced pancreatic function and only partially related to oral antibiotic administration or lung colonization/infection.

CONCLUSIONS: All together, the results obtained suggest that the gut microbiota enterophenotypes of CF, together with endogenous and bacterial CF biomarkers, are direct expression of functional alterations at the intestinal level. Hence, it's possible to infer that CFTR impairment causes the gut ecosystem imbalance.This new understanding of CF host-gut microbiota interactions may be helpful to rationalize novel clinical interventions to improve the affected children's nutritional status and intestinal function.

RevDate: 2018-12-06

Yoshikawa A, Goto R, A Asakura (2018)

Morphology and Habitats of the Hermit-Crab-Associated Calyptraeid Gastropod Ergaea walshi.

Zoological science, 35(6):494-504.

Ergaea walshi, a gastropod with a markedly flat shell, often lives inside empty snail shells occupied by hermit crabs. We investigated its lifestyle, shell growth pattern, and habitat preference for host hermit crabs and host snail shells. Four hundred sixteen snail shells, including 363 shells with hermit crabs and 53 empty shells, were collected from intertidal zones of sandy and muddy flats around Kii Peninsula, Japan. The specimens comprised seven hermit crab species occupying 24 shell species; E. walshi was harbored in 13.2% of snail shells with hermit crabs and 17.0% of those without hermit crabs. Although no preference was detected for particular species of hermit crab or snail shell, E. walshi preferred to live inside of snail shells with wider apertures used by comparatively bigger hermit crabs. This suggests that the occurrence of E. walshi was influenced by host size rather than host species. When looking at growth patterns, we found that the attached shell portion of E. walshi continued to be enlarged horizontally, while growth in shell height slowed at approximately 5.0 mm. The conspicuously flattened shell of E. walshi is considered as a growth pattern for adapting to the narrow space within the snail shell occupied by hermit crabs. Consistent with this idea, our comparison of shell growth patterns in 23 calyptraeid species showed that shell of E. walshi is the flattest in this family.

RevDate: 2018-12-06

Kountche BA, Novero M, Jamil M, et al (2018)

Effect of the strigolactone analogs methyl phenlactonoates on spore germination and root colonization of arbuscular mycorrhizal fungi.

Heliyon, 4(11):e00936 pii:e00936.

Strigolactones (SLs), a novel class of plant hormones, are key regulator of plant architecture and mediator of biotic interactions in the rhizosphere. Root-released SLs initiate the establishment of arbuscular mycorrhizal (AM) symbiosis by inducing spore germination and hyphal branching in AM fungi (AMF). However, these compounds also trigger the germination of root parasitic weeds, paving the way for deleterious infestation. Availability of SLs is required for investigating of their functions and also for application in agriculture. However, natural SLs are difficult to synthesize due to their complex structure and cannot be isolated at large scale, as they are released at very low concentrations. Therefore, there is a need for synthetic SL analogs. Recently, we reported on the development of simple SL analogs, methyl phenlactonoates (MPs), which show high SL activity in plants. Here, we investigate the effect of MP1, MP3 and the widely used SL-analog GR24 on AMF spore germination and host root colonization. Our results show that MP1 and MP3 inhibit AMF spore germination, but promote the intra-radical root colonization, both more efficiently than GR24. These results indicate that field application of MP1 and MP3 does not have negative impact on mycorrhizal fungi. In conclusion, our data together with the previously reported simple synthesis, high activity in regulating plant architecture and inducing Striga seed germination, demonstrate the utility of MP1 and MP3 as for field application in combating root parasitic weeds by inducing germination in host's absence.

RevDate: 2018-12-06

Bertoloni Meli S, F Bashey (2018)

Trade-off between reproductive and anti-competitor abilities in an insect-parasitic nematode-bacteria symbiosis.

Ecology and evolution, 8(22):10847-10856 pii:ECE34538.

Mutualistic symbionts can provide diverse benefits to their hosts and often supply key trait variation for host adaptation. The bacterial symbionts of entomopathogenic nematodes play a crucial role in successful colonization of and reproduction in the insect host. Additionally, these symbionts can produce a diverse array of antimicrobial compounds to deter within-host competitors. Natural isolates of the symbiont, Xenorhabdus bovienii, show considerable variation in their ability to target sympatric competitors via bacteriocins, which can inhibit the growth of sensitive Xenorhabdus strains. Both the bacteria and its nematode partner have been shown to benefit from bacteriocin production when within-host competition with a sensitive competitor occurs. Despite this benefit, several isolates of Xenorhabdus do not inhibit sympatric strains. To understand how this variation in allelopathy could be maintained, we tested the hypothesis that inhibiting isolates face a reproductive cost in the absence of competition. We tested this hypothesis by examining the reproductive success of inhibiting and non-inhibiting isolates coupled with their natural nematode host in a non-competitive context. We found that nematodes carrying non-inhibitors killed the insect host more rapidly and were more likely to successfully reproduce than nematodes carrying inhibitors. Lower reproductive success of inhibiting isolates was repeatable across nematode generations and across insect host species. However, no difference in insect mortality was observed between inhibiting and non-inhibiting isolates when bacteria were injected into insects without their nematode partners. Our results indicate a trade-off between the competitive and reproductive roles of symbionts, such that inhibiting isolates, which are better in the face of within-host competition, pay a reproductive cost in the absence of competition. Furthermore, our results support the hypothesis that symbiont variation within populations can be maintained through context-dependent fitness benefits conferred to their hosts. As such, our study offers novel insights into the selective forces maintaining variation within a single host-symbiont population and highlights the role of competition in mutualism evolution.

RevDate: 2018-12-06

Burmester EM, Breef-Pilz A, Lawrence NF, et al (2018)

The impact of autotrophic versus heterotrophic nutritional pathways on colony health and wound recovery in corals.

Ecology and evolution, 8(22):10805-10816 pii:ECE34531.

For animals that harbor photosynthetic symbionts within their tissues, such as corals, the different relative contributions of autotrophy versus heterotrophy to organismal energetic requirements have direct impacts on fitness. This is especially true for facultatively symbiotic corals, where the balance between host-caught and symbiont-produced energy can be altered substantially to meet the variable demands of a shifting environment. In this study, we utilized a temperate coral-algal system (the northern star coral, Astrangia poculata, and its photosynthetic endosymbiont, Symbiodinium psygmophilum) to explore the impacts of nutritional sourcing on the host's health and ability to regenerate experimentally excised polyps. For fed and starved colonies, wound healing and total colony tissue cover were differentially impacted by heterotrophy versus autotrophy. There was an additive impact of positive nutritional and symbiotic states on a coral's ability to initiate healing, but a greater influence of symbiont state on the recovery of lost tissue at the lesion site and complete polyp regeneration. On the other hand, regardless of symbiont state, fed corals maintained a higher overall colony tissue cover, which also enabled more active host behavior (polyp extension) and endosymbiont behavior (photosynthetic ability of Symbiondinium). Overall, we determined that the impact of nutritional state and symbiotic state varied between biological functions, suggesting a diversity in energetic sourcing for each of these processes.

RevDate: 2018-12-06

Bolin LG, Benning JW, DA Moeller (2018)

Mycorrhizal interactions do not influence plant-herbivore interactions in populations of Clarkia xantiana ssp. xantiana spanning from center to margin of the geographic range.

Ecology and evolution, 8(22):10743-10753 pii:ECE34523.

Multispecies interactions can be important to the expression of phenotypes and in determining patterns of individual fitness in nature. Many plants engage in symbiosis with arbuscular mycorrhizal fungi (AMF), but the extent to which AMF modulate other species interactions remains poorly understood. We examined multispecies interactions among plants, AMF, and insect herbivores under drought stress using a greenhouse experiment and herbivore choice assays. The experiment included six populations of Clarkia xantiana (Onagraceae), which span a complex environmental gradient in the Southern Sierra Nevada of California. Clarkia xantiana's developing fruits are commonly attacked by grasshoppers at the end of the growing season, and the frequency of attack is more common in populations from the range center than range margin. We found that AMF negatively influenced all metrics of plant growth and reproduction across all populations, presumably because plants supplied carbon to AMF but did not benefit substantially from resources potentially supplied by the AMF. The fruits of plants infected with AMF did not differ from those without AMF in their resistance to grasshoppers. There was significant variation among populations in damage from herbivores but did not reflect the center-to-margin pattern of herbivory observed in the field. In sum, our results do not support the view that AMF interactions modulate plant-herbivore interactions in this system.

RevDate: 2018-12-06

Temprano-Vera F, Rodríguez-Navarro DN, Acosta-Jurado S, et al (2018)

Sinorhizobium fredii Strains HH103 and NGR234 Form Nitrogen Fixing Nodules With Diverse Wild Soybeans (Glycine soja) From Central China but Are Ineffective on Northern China Accessions.

Frontiers in microbiology, 9:2843.

Sinorhizobium fredii indigenous populations are prevalent in provinces of Central China whereas Bradyrhizobium species (Bradyrhizobium japonicum, B. diazoefficiens, B. elkanii, and others) are more abundant in northern and southern provinces. The symbiotic properties of different soybean rhizobia have been investigated with 40 different wild soybean (Glycine soja) accessions from China, Japan, Russia, and South Korea. Bradyrhizobial strains nodulated all the wild soybeans tested, albeit efficiency of nitrogen fixation varied considerably among accessions. The symbiotic capacity of S. fredii HH103 with wild soybeans from Central China was clearly better than with the accessions found elsewhere. S. fredii NGR234, the rhizobial strain showing the broadest host range ever described, also formed nitrogen-fixing nodules with different G. soja accessions from Central China. To our knowledge, this is the first report describing an effective symbiosis between S. fredii NGR234 and G. soja. Mobilization of the S. fredii HH103 symbiotic plasmid to a NGR234 pSym-cured derivative (strain NGR234C) yielded transconjugants that formed ineffective nodules with G. max cv. Williams 82 and G. soja accession CH4. By contrast, transfer of the symbiotic plasmid pNGR234a to a pSym-cured derivative of S. fredii USDA193 generated transconjugants that effectively nodulated G. soja accession CH4 but failed to nodulate with G. max cv. Williams 82. These results indicate that intra-specific transference of the S. fredii symbiotic plasmids generates new strains with unpredictable symbiotic properties, probably due to the occurrence of new combinations of symbiotic signals.

RevDate: 2018-12-06

Tena G (2018)

Symbiosis gatekeeper.

Nature plants, 4(12):982.

RevDate: 2018-12-06

Brottier L, Chaintreuil C, Simion P, et al (2018)

A phylogenetic framework of the legume genus Aeschynomene for comparative genetic analysis of the Nod-dependent and Nod-independent symbioses.

BMC plant biology, 18(1):333 pii:10.1186/s12870-018-1567-z.

BACKGROUND: Among semi-aquatic species of the legume genus Aeschynomene, some have the property of being nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the synthesis of Nod factors. Knowledge of the specificities underlying this Nod-independent symbiosis has been gained from the model legume Aeschynomene evenia but our understanding remains limited due to the lack of comparative genetics with related taxa using a Nod factor-dependent process. To fill this gap, we combined different approaches to perform a thorough comparative analysis in the genus Aeschynomene.

RESULTS: This study significantly broadened previous taxon sampling, including in allied genera, in order to construct a comprehensive phylogeny. In the phylogenetic tree, five main lineages were delineated, including a novel lineage, the Nod-independent clade and another one containing a polytomy that comprised several Aeschynomene groups and all the allied genera. This phylogeny was matched with data on chromosome number, genome size and low-copy nuclear gene sequences to reveal the diploid species and a polytomy containing mostly polyploid taxa. For these taxa, a single allopolyploid origin was inferred and the putative parental lineages were identified. Finally, nodulation tests with different Bradyrhizobium strains revealed new nodulation behaviours and the diploid species outside of the Nod-independent clade were compared for their experimental tractability and genetic diversity.

CONCLUSIONS: The extended knowledge of the genetics and biology of the different lineages sheds new light of the evolutionary history of the genus Aeschynomene and they provide a solid framework to exploit efficiently the diversity encountered in Aeschynomene legumes. Notably, our backbone tree contains all the species that are diploid and it clarifies the genetic relationships between the Nod-independent clade and the Nod-dependent lineages. This study enabled the identification of A. americana and A. patula as the most suitable species to undertake a comparative genetic study of the Nod-independent and Nod-dependent symbioses.

RevDate: 2018-12-03

Hsiao CC, Sieber S, Georgiou A, et al (2018)

Synthesis and Biological Evaluation of the Novel Growth Inhibitor Streptol Glucoside, Isolated from an Obligate Plant Symbiont.

Chemistry (Weinheim an der Bergstrasse, Germany) [Epub ahead of print].

The plant Psychotria kirkii hosts an obligatory bacterial symbiont, Candidatus Burkholderia kirkii, in nodules on their leaves. Recently, a glucosylated derivative of (+)-streptol, (+)-streptol glucoside, was isolated from the nodulated leaves and was found to possess a plant growth inhibitory activity. To establish a structure activity relationship study, a convergent strategy was developed to obtain several pseudosugars from a single synthetic precursor. Furthermore, the glucosylation of streptol was investigated in detail and conditions affording specifically the alpha or beta glucosidic anomer were identified. Although (+)-streptol was the most active compound, its concentration in P. kirkii plant leaves extract was approximately 10 fold lower than that of (+)-streptol glucoside. These results provide compelling evidence that the glucosylation of (+)-streptol protects the plant host against the growth inhibitory effect of the compound, which might constitute a molecular cornerstone for this successful plant-bacteria symbiosis.

RevDate: 2018-12-03

Wasilko NP, Larios-Valencia J, Steingard CH, et al (2018)

Sulfur availability for Vibrio fischeri growth during symbiosis establishment depends on biogeography within the squid light organ.

Molecular microbiology [Epub ahead of print].

The fitness of host-associated microbes depends on their ability to access nutrients in vivo. Identifying these mechanisms is significant for understanding how microbes have evolved to fill specific ecological niches within a host. Vibrio fischeri is a bioluminescent bacterium that colonizes and proliferates within the light organ of the Hawaiian bobtail squid, which provides an opportunity to study how bacteria grow in vivo. Here, the transcription factor CysB is shown to be necessary for V. fischeri both to grow on several sulfur sources in vitro and to establish symbiosis with juvenile squid. CysB is also found to regulate several genes involved in sulfate assimilation and to contribute to the growth of V. fischeri on cystine, which is the oxidized form of cysteine. A mutant that grows on cystine but not sulfate could establish symbiosis, suggesting that V. fischeri acquires nutrients related to this compound within the host. Finally, CysB-regulated genes are shown to be differentially expressed among the V. fischeri populations occupying the various colonization sites found within the light organ. Together, these results suggest the biogeography of V. fischeri populations within the squid light organ impacts the physiology of this symbiotic bacterium in vivo through CysB-dependent gene regulation. This article is protected by copyright. All rights reserved.

RevDate: 2018-12-03

Pardo-De la Hoz CJ, Magain N, Lutzoni F, et al (2018)

Contrasting Symbiotic Patterns in Two Closely Related Lineages of Trimembered Lichens of the Genus Peltigera.

Frontiers in microbiology, 9:2770.

Species circumscription is key to the characterization of patterns of specificity in symbiotic systems at a macroevolutionary scale. Here, a worldwide phylogenetic framework was used to assess the biodiversity and symbiotic patterns of association among partners in trimembered lichens from the genus Peltigera, section Chloropeltigera. We sequenced six loci of the main fungal partner and performed species discovery and validation analyses to establish putative species boundaries. Single locus phylogenies were used to establish the identity of both photobionts, Nostoc (cyanobacterium) and Coccomyxa (green alga). Distribution and specificity patterns were compared to the closely related clade, section Peltidea, which includes mainly Peltigera species with trimembered thalli. For section Chloropeltigera, eight fungal species (including five newly delimited putative species) were found in association with nine Nostoc phylogroups and two Coccomyxa species. In contrast, eight fungal species (including three newly delimited putative species) in section Peltidea were found in association with only four Nostoc phylogroups and the same two Coccomyxa species as for section Chloropeltigera. This difference in cyanobiont biodiversity between these two sections can potentially be explained by a significantly higher frequency of sexual reproductive structures in species from section Chloropeltigera compared to section Peltidea. Therefore, horizontal transmission of the cyanobiont might be more prevalent in Chloropeltigera species, while vertical transmission might be more common in Peltidea species. All Peltigera species in section Chloropeltigera are generalists in their association with Nostoc compared to more specialized Peltigera species in section Peltidea. Constrained distributions of Peltigera species that associate strictly with one species of green algae (Coccomyxa subellipsoidea) indicate that the availability of the green alga and the specificity of the interaction might be important factors limiting geographic ranges of trimembered Peltigera, in addition to constraints imposed by their interaction with Nostoc partners and by climatic factors.

RevDate: 2018-12-03

Nazha A (2018)

The MDS genomics-prognosis symbiosis.

Hematology. American Society of Hematology. Education Program, 2018(1):270-276.

Myelodysplastic syndromes (MDS) are clonal disorders characterized by the accumulation of complex genomic abnormalities that define disease phenotype, prognosis, and the risk of transformation to acute myeloid leukemia. The clinical manifestations and overall outcomes of MDS are very heterogeneous with an overall survival that can be measured in years for some patients to a few months for others. Prognostic scoring systems are important staging tools that aid physicians in their treatment recommendations and decision-making and can help patients understand their disease trajectory and expectations. Several scoring systems have been developed in MDS with the International Prognostic Scoring System and its revised version, the most widely used systems in clinical practice and trial eligibility. These models and others use mainly clinical variables that are obtained from bone marrow biopsy and peripheral blood measurements. Adding molecular data to current models may improve its predictive power but the ultimate method to incorporate this information remains a work in progress. Novel methods to develop a personalized prediction model that provides outcomes that are specific for a patient are currently under way and may change how we think about risk stratification in MDS patients in the future.

RevDate: 2018-12-03

Tokuda G, Mikaelyan A, Fukui C, et al (2018)

Fiber-associated spirochetes are major agents of hemicellulose degradation in the hindgut of wood-feeding higher termites.

Proceedings of the National Academy of Sciences of the United States of America pii:1810550115 [Epub ahead of print].

Symbiotic digestion of lignocellulose in wood-feeding higher termites (family Termitidae) is a two-step process that involves endogenous host cellulases secreted in the midgut and a dense bacterial community in the hindgut compartment. The genomes of the bacterial gut microbiota encode diverse cellulolytic and hemicellulolytic enzymes, but the contributions of host and bacterial symbionts to lignocellulose degradation remain ambiguous. Our previous studies of Nasutitermes spp. documented that the wood fibers in the hindgut paunch are consistently colonized not only by uncultured members of Fibrobacteres, which have been implicated in cellulose degradation, but also by unique lineages of Spirochaetes. Here, we demonstrate that the degradation of xylan, the major component of hemicellulose, is restricted to the hindgut compartment, where it is preferentially hydrolyzed over cellulose. Metatranscriptomic analysis documented that the majority of glycoside hydrolase (GH) transcripts expressed by the fiber-associated bacterial community belong to family GH11, which consists exclusively of xylanases. The substrate specificity was further confirmed by heterologous expression of the gene encoding the predominant homolog. Although the most abundant transcripts of GH11 in Nasutitermes takasagoensis were phylogenetically placed among their homologs of Firmicutes, immunofluorescence microscopy, compositional binning of metagenomics contigs, and the genomic context of the homologs indicated that they are encoded by Spirochaetes and were most likely obtained by horizontal gene transfer among the intestinal microbiota. The major role of spirochetes in xylan degradation is unprecedented and assigns the fiber-associated Treponema clades in the hindgut of wood-feeding higher termites a prominent part in the breakdown of hemicelluloses.

RevDate: 2018-12-03

Shaaban M, Elgaml A, EE Habib (2018)

Biotechnological applications of quorum sensing inhibition as novel therapeutic strategies for multidrug resistant pathogens.

Microbial pathogenesis pii:S0882-4010(18)30585-0 [Epub ahead of print].

High incidence of antibiotic resistance among bacterial clinical isolates necessitates the discovery of new targets for inhibition of microbial pathogenicity without stimulation of microbial resistance. This could be achieved by targeting virulence determinants which cause host damage and disease. Many pathogenic bacteria elaborate signaling molecules for cellular communication. This signaling system is named quorum sensing system (QS), and it is contingent on the bacterial population density and mediated by signal molecules called pheromones or autoinducers (AIs). Bacteria utilize QS to regulate activities and behaviors including competence, conjugation, symbiosis, virulence, motility, sporulation, antibiotic production, and biofilm formation. Hence, targeting bacterial communicating signals and suppression of QS exhibit a fundamental approach for competing microbial communication. In this review, we illustrate the common up to date approaches to utilize QS circuits in pathogenic bacteria, including Vibrio fischeri, Pseudomonas aeruginosa, Escherichia coli and Acinetobacter baumannii, as novel therapeutic targets.

RevDate: 2018-12-03

Dargahi N, Johnson J, Donkor O, et al (2019)

Immunomodulatory effects of probiotics: Can they be used to treat allergies and autoimmune diseases?.

Maturitas, 119:25-38.

As a person ages, physiological, immunological and gut microbiome changes collectively result in an array of chronic conditions. According to the 'hygiene hypothesis' the increasing prevalence of immune-mediated disorders may be related to intestinal dysbiosis, leading to immune dysfunction and associated conditions such as eczema, asthma, allergies and autoimmune diseases. Beneficial probiotic bacteria can be utilized by increasing their abundance within the gastrointestinal lumen, which in turn will modulate immune cells, such as, T helper (Th)-1, Th2, Th17, regulatory T (Treg) cells and B cells, which have direct relevance to human health and the pathogenesis of immune disorders. Here, we describe the cross-talk between probiotics and the gastrointestinal immune system, and their effects in relation to inflammatory bowel disease, multiple sclerosis, allergies and atopic dermatitis.

RevDate: 2018-12-03

Wang H, Tang W, Zhang R, et al (2018)

Analysis of enzyme activity, antibacterial activity, antiparasitic activity and physico-chemical stability of skin mucus derived from Amphiprion clarkii.

Fish & shellfish immunology pii:S1050-4648(18)30785-X [Epub ahead of print].

Recently, mucosal surfaces, especially fish skin and its secreted mucus, have attracted significant interest from immunologists. Amphiprion clarkii, a member of the family Pomacentridae, lives symbiosis with sea anemones and has a good resistance to common seawater bacterial diseases and parasites owing to the protection from its abundant skin mucus. In the present work, the activity of immune-related enzymes (lysozyme, protease, antiprotease, cathepsin B, alkaline phosphatase and peroxidase), the antibacterial activity against two Gram-positive bacteria and five Gram-negative bacteria, the antiparasitic activity against the pathogen of marine white spot disease (Cryptocaryon irritans theronts) and the physico-chemical stability (to pH and heat) of the skin mucus of A. clarkii were analysed. The results showed that the levels of lysozyme and peroxidase were very similar (from 2 to 4 U mg-1 protein). However, cathepsin B was detected of 63.32 U mg-1 protein and alkaline phosphatase was only 0.12 U mg-1 protein. Moreover, protease showed a higher percentage of activity than antiprotease. A. clarkii skin mucus showed a strong antibacterial activity against Gram-negative bacteria, particularly against Aeromonas hydrophila and Vibrio parahaemolyticus but showed no effect on Gram-positive bacteria at the tested concentrations. The bactericidal activity functioned within a short time in a distinct time- and dose-dependent manner. SEM showed that after treated with A. clarkii skin mucus, the V. parahaemolyticus cells distorted and piled together, and the filaments appeared and became into cotton-shaped or quasi-honeycomb texture to adhere cells. Meanwhile, A. clarkii skin mucus showed an apparent antiparasitic activity against C. irritans theronts with a distinct dose- and time-dependent relationship. LM and SEM observation showed that after treated with skin mucus, the theronts quickly stopped their swimming and cilia movement, cells beacme rounded, cilia shed, small bubbles formed on the surface, cell nucleolus enlarged, cytoskeleton deformed, cell membranes ruptured and cell content leaked out. Antibacterial activity was not affected by 30-90 °C heat treatment but was slightly suppressed by 100 °C. In the pH treatment groups, antibacterial activity was not affected by the moderate pH treatment of 5.0-8.0, and slightly suppressed by weak acid and weak base. Therefore, we speculated that the skin mucus of A. clarkii might be a potential source of novel antibacterial and antiparasitic components for fish or human health-related applications. This study broadened our understanding of the role of skin mucus in the innate immune system and provided a basis for the further isolation and purification of active substances.

RevDate: 2018-12-05

Fuente AL, Urcuyo RJ, GH Vega (2018)

Protists and other organisms on a minute snail periostracum.

Brazilian journal of biology = Revista brasleira de biologia pii:S1519-69842018005033101 [Epub ahead of print].

Since the foundation of the Malacological Center in 1980, Universidad Centro Americana (UCA), Managua-Nicaragua, has been monitoring and collecting the marine, terrestrial, fluvial and lake mollusk population of the country. Many specimens have been photographed by Scanning Electronic Microscope (SEM), and in one of these, observation of the hairy periostracum reveals a seemingly thriving population of minute protists in possible symbiosis with their host. Adequate magnification and comparison with previous studies allowed the determination of these hosts as diatoms, testaceous amoebae, yeast, phacus, spores and other undetermined organisms which occur in tropical forests on rocks, trees and leaves. Here illustrated are diatoms and other organisms detected for the first time on the periostracum of a tropical rainforest mollusk.

RevDate: 2018-12-05

Gil-Martínez M, López-García Á, Domínguez MT, et al (2018)

Ectomycorrhizal Fungal Communities and Their Functional Traits Mediate Plant-Soil Interactions in Trace Element Contaminated Soils.

Frontiers in plant science, 9:1682.

There is an increasing consensus that microbial communities have an important role in mediating ecosystem processes. Trait-based ecology predicts that the impact of the microbial communities on ecosystem functions will be mediated by the expression of their traits at community level. The link between the response of microbial community traits to environmental conditions and its effect on plant functioning is a gap in most current microbial ecology studies. In this study, we analyzed functional traits of ectomycorrhizal fungal species in order to understand the importance of their community assembly for the soil-plant relationships in holm oak trees (Quercus ilex subsp. ballota) growing in a gradient of exposure to anthropogenic trace element (TE) contamination after a metalliferous tailings spill. Particularly, we addressed how the ectomycorrhizal composition and morphological traits at community level mediate plant response to TE contamination and its capacity for phytoremediation. Ectomycorrhizal fungal taxonomy and functional diversity explained a high proportion of variance of tree functional traits, both in roots and leaves. Trees where ectomycorrhizal fungal communities were dominated by the abundant taxa Hebeloma cavipes and Thelephora terrestris showed a conservative root economics spectrum, while trees colonized by rare taxa presented a resource acquisition strategy. Conservative roots presented ectomycorrhizal functional traits characterized by high rhizomorphs formation and low melanization which may be driven by resource limitation. Soil-to-root transfer of TEs was explained substantially by the ectomycorrhizal fungal species composition, with the highest transfer found in trees whose roots were colonized by Hebeloma cavipes. Leaf phosphorus was related to ectomycorrhizal species composition, specifically higher leaf phosphorus was related to the root colonization by Thelephora terrestris. These findings support that ectomycorrhizal fungal community composition and their functional traits mediate plant performance in metal-contaminated soils, and have a high influence on plant capacity for phytoremediation of contaminants. The study also corroborates the overall effects of ectomycorrhizal fungi on ecosystem functioning through their mediation over the plant economics spectrum.

RevDate: 2018-12-05

Nath A, Molnár MA, Csighy A, et al (2018)

Biological Activities of Lactose-Based Prebiotics and Symbiosis with Probiotics on Controlling Osteoporosis, Blood-Lipid and Glucose Levels.

Medicina (Kaunas, Lithuania), 54(6): pii:medicina54060098.

Lactose-based prebiotics are synthesized by enzymatic- or microbial- biotransformation of lactose and have unique functional values. In this comprehensive review article, the biochemical mechanisms of controlling osteoporosis, blood-lipid, and glucose levels by lactose-based prebiotics and symbiosis with probiotics are reported along with the results of clinical investigations. Interaction between lactose-based prebiotics and probiotics reduces osteoporosis by (a) transforming insoluble inorganic salts to soluble and increasing their absorption to gut wall; (b) maintaining and protecting mineral absorption surface in the intestine; (c) increasing the expression of calcium-binding proteins in the gut wall; (d) remodeling osteoclasts and osteoblasts formation; (e) releasing bone modulating factors; and (f) degrading mineral complexing phytic acid. Lactose-based prebiotics with probiotics control lipid level in the bloodstream and tissue by (a) suppressing the expressions of lipogenic- genes and enzymes; (b) oxidizing fatty acids in muscle, liver, and adipose tissue; (c) binding cholesterol with cell membrane of probiotics and subsequent assimilation by probiotics; (d) enzymatic-transformations of bile acids; and (e) converting cholesterol to coprostanol and its defecation. Symbiosis of lactose-based prebiotics with probiotics affect plasma glucose level by (a) increasing the synthesis of gut hormones plasma peptide-YY, glucagon-like peptide-1 and glucagon-like peptide-2 from entero-endocrine L-cells; (b) altering glucose assimilation and metabolism; (c) suppressing systematic inflammation; (d) reducing oxidative stress; and (e) producing amino acids. Clinical investigations show that lactose-based prebiotic galacto-oligosaccharide improves mineral absorption and reduces hyperlipidemia. Another lactose-based prebiotic, lactulose, improves mineral absorption, and reduces hyperlipidemia and hyperglycemia. It is expected that this review article will be of benefit to food technologists and medical practitioners.

RevDate: 2018-12-04

Chen S, Shao G, Shao F, et al (2018)

[Diffusion-weighted imaging texture features in differentiation of malignant from benign nonpalpable breast lesions for patients with microcalcifications-only in mammography].

Zhejiang da xue xue bao. Yi xue ban = Journal of Zhejiang University. Medical sciences, 47(4):400-404.

OBJECTIVE: To evaluate the application of MR diffusion-weighted imaging(DWI) texture features in differentiation of malignant from benign nonpalpable breast lesion for patients with microcalcifications-only in mammography.

METHODS: The clinical and MR-DWI data of 61 patients with microcalcifications, who underwent three-dimensional positioning of breast X-ray wire from October 2012 to December 2015 in Zhejiang Cancer Hospital, were retrospectively analyzed, including 38 patients with malignant lesions and 23 patients with benign lesions. Two radiologists independently drew the regions of interest (ROI) on DWI for image segmentation, and 6 histogram features and 16 grayscale symbiosis matrix (GLCM) texture features were extracted on each ROI. The random forest algorithm was applied to select the features and built the classification model. The leave-one-out cross-validation (LOOCV) was used to validate the classifier, and the performance of the classifier was evaluated by ROC curve.

RESULTS: Six features were selected, including histogram features of mean, variance, skewness, entropy, as well as contrast (0°) and correlation (45°) in GLCM. The histogram features of mean, variance, skewness and entropy were significantly different between the benign and malignant breast lesions (all P<0.05). The AUC of the model was 0.76, and the diagnostic accuracy, sensitivity and specificity were 77.05%, 84.21% and 65.21%, respectively.

CONCLUSIONS: The texture feature analysis of DWI can improve the diagnostic accuracy of differentiating benign and malignant breast nonpalpable lesions with microcalcifications-only in mammography. Histogram features of mean, variance, skewness, entropy of DWI may be used as important imaging markers.

RevDate: 2018-12-04

Hernandez AE, Claussenius-Kalman HL, Ronderos J, et al (2018)

Symbiosis, Parasitism and Bilingual Cognitive Control: A Neuroemergentist Perspective.

Frontiers in psychology, 9:2171.

Interest in the intersection between bilingualism and cognitive control and accessibility to neuroimaging methods has resulted in numerous studies with a variety of interpretations of the bilingual cognitive advantage. Neurocomputational Emergentism (or Neuroemergentism for short) is a new framework for understanding this relationship between bilingualism and cognitive control. This framework considers Emergence, in which two small elements are recombined in an interactive manner, yielding a non-linear effect. Added to this is the notion that Emergence can be captured in neural systems using computationally inspired models. This review poses that bilingualism and cognitive control, as examined through the Neuroemergentist framework, are interwoven through development and involve the non-linear growth of cognitive processing encompassing brain areas that combine and recombine, in symbiotic and parasitic ways, in order to handle more complex types of processing. The models that have sought to explain the neural substrates of bilingual cognitive differences will be discussed with a reinterpretation of the entire bilingual cognitive advantage within a Neuroemergentist framework incorporating its neural bases. It will conclude by discussing how this new Neuroemergentist approach alters our view of the effects of language experience on cognitive control. Avenues to move beyond the simple notion of a bilingual advantage or lack thereof will be proposed.

RevDate: 2018-11-30

Lopes LE, Waldis SJ, Terrell SM, et al (2018)

Vibrant symbiosis: Achieving reciprocal science outreach through biological art.

PLoS biology, 16(11):e3000061 pii:PBIOLOGY-D-18-00411 [Epub ahead of print].

Scientific outreach efforts traditionally involve formally trained scientists teaching the general public about the methods, significance, and excitement of science. We recently experimented with an alternative "symbiotic outreach" model that prioritizes building a reciprocal relationship between formally trained and "outsider" scientists to facilitate active two-way communication. Herein, we present the results of our outreach effort involving college students and adults with intellectual and developmental disabilities working together to make biological and multimedia art. By discussing the steps others can take to cultivate reciprocal outreach within their local communities, we hope to lower the barrier for widespread adoption of similar approaches and ultimately to decrease the gap between formally trained scientists and the general public.

RevDate: 2018-11-30

Tsaftaris SA, H Scharr (2018)

Sharing the Right Data Right: A Symbiosis with Machine Learning.

Trends in plant science pii:S1360-1385(18)30249-8 [Epub ahead of print].

In 2014 plant phenotyping research was not benefiting from the machine learning (ML) revolution because appropriate data were lacking. We report the success of the first open-access dataset suitable for ML in image-based plant phenotyping suitable for machine learning, fuelling a true interdisciplinary symbiosis, increased awareness, and steep performance improvements on key phenotyping tasks.

RevDate: 2018-11-29

Khasa R, Vaidya A, Vrati S, et al (2018)

Membrane trafficking RNA interference screen identifies a crucial role of the clathrin endocytic pathway and ARP2/3 complex for Japanese encephalitis virus infection in HeLa cells.

The Journal of general virology [Epub ahead of print].

Japanese encephalitis virus (JEV), a mosquito-borne flavivirus, is one of the leading global causes of virus-induced encephalitis. The infectious life-cycle of viruses is heavily dependent on the host membrane trafficking network. Here, we have performed a RNA-interference-based screen using a siRNA panel targeting 136 membrane trafficking proteins to identify the key regulators of JEV infection in HeLa cells. We identified 35 proteins whose siRNA depletion restricts JEV replication by over twofold. We observe that JEV infection in HeLa cells is largely dependent on components of the clathrin-mediated endocytic (CME) pathway. Proteins involved in actin-filament-based processes, specifically CDC42 and members of the ARP2/3 complex are crucial for establishment of infection. Pharmacological pertubations of actin polymerization, a small molecule inhibitor of actin nucleation by the ARP2/3 complex - CK-548 - and the inhibitor of neural Wiskott-Aldrich syndrome proteins- Wiskostatin- inhibited JEV replication, highlighting the important role of the dynamic actin network. Other proteins involved in cargo-recognition for CME and endomembrane system organization were also validated as essential host factors for virus replication.

RevDate: 2018-11-29

Paulitsch F, Klepa MS, da Silva AR, et al (2018)

Phylogenetic diversity of rhizobia nodulating native Mimosa gymnas grown in a South Brazilian ecotone.

Molecular biology reports pii:10.1007/s11033-018-4506-z [Epub ahead of print].

Floristic surveys performed in "Campos Gerais" (Paraná, Brazil), an ecotone of Mata Atlântica and Cerrado biomes, highlights the richness and relative abundance of the family Fabaceae and point out the diversity and endemism of Mimosa spp. Our study reports the genetic diversity of rhizobia isolated from root nodules of native/endemic Mimosa gymnas Barneby in three areas of Guartelá State Park, an important conservation unit of "Campos Gerais". Soils of the sample areas were characterized as sandy, acid, poor in nutrients and organic matter. The genetic variability among the isolates was revealed by BOX-PCR genomic fingerprinting. Phylogeny based on 16S rRNA gene grouped the strains in a large cluster including Paraburkholderia nodosa and P. bannensis, while recA-gyrB phylogeny separated the strains in two groups: one including P. nodosa and the other without any described Paraburkholderia species. MLSA confirmed the separate position of this second group of strains within the genus Paraburkholderia and the nucleotide identity of the five concatened housekeeping genes was 95.9% in relation to P. nodosa BR 3437T. Phylogram based on symbiosis-essential nodC gene was in agreement with 16S rRNA analysis. Our molecular phylogenetic analysis support that Paraburkholderia are the main symbionts of native Mimosa in specific edaphic conditions found in South America and reveal the importance of endemic/native leguminous plants as reservoirs of novel rhizobial species.

RevDate: 2018-11-29

Matthews JL, Oakley CA, Lutz A, et al (2018)

Partner switching and metabolic flux in a model cnidarian-dinoflagellate symbiosis.

Proceedings. Biological sciences, 285(1892): pii:rspb.2018.2336.

Metabolite exchange is fundamental to the viability of the cnidarian-Symbiodiniaceae symbiosis and survival of coral reefs. Coral holobiont tolerance to environmental change might be achieved through changes in Symbiodiniaceae species composition, but differences in the metabolites supplied by different Symbiodiniaceae species could influence holobiont fitness. Using 13C stable-isotope labelling coupled to gas chromatography-mass spectrometry, we characterized newly fixed carbon fate in the model cnidarian Exaiptasia pallida (Aiptasia) when experimentally colonized with either native Breviolum minutum or non-native Durusdinium trenchii Relative to anemones containing B. minutum, D. trenchii-colonized hosts exhibited a 4.5-fold reduction in 13C-labelled glucose and reduced abundance and diversity of 13C-labelled carbohydrates and lipogenesis precursors, indicating symbiont species-specific modifications to carbohydrate availability and lipid storage. Mapping carbon fate also revealed significant alterations to host molecular signalling pathways. In particular, D. trenchii-colonized hosts exhibited a 40-fold reduction in 13C-labelled scyllo-inositol, a potential interpartner signalling molecule in symbiosis specificity. 13C-labelling also highlighted differential antioxidant- and ammonium-producing pathway activities, suggesting physiological responses to different symbiont species. Such differences in symbiont metabolite contribution and host utilization may limit the proliferation of stress-driven symbioses; this contributes valuable information towards future scenarios that select in favour of less-competent symbionts in response to environmental change.

RevDate: 2018-11-28

Chan CK, Rosic N, Lorenc MT, et al (2018)

A differential k-mer analysis pipeline for comparing RNA-Seq transcriptome and meta-transcriptome datasets without a reference.

Functional & integrative genomics pii:10.1007/s10142-018-0647-3 [Epub ahead of print].

Next-generation DNA sequencing technologies, such as RNA-Seq, currently dominate genome-wide gene expression studies. A standard approach to analyse this data requires mapping sequence reads to a reference and counting the number of reads which map to each gene. However, for many transcriptome studies, a suitable reference genome is unavailable, especially for meta-transcriptome studies which assay gene expression from mixed populations of organisms. Where a reference is unavailable, it is possible to generate a reference by the de novo assembly of the sequence reads. However, the high cost of generating high-coverage data for de novo assembly hinders this approach and more importantly the accurate assembly of such data is challenging, especially for meta-transcriptome data, and resulting assemblies frequently suffer from collapsed regions or chimeric sequences. As an alternative to the standard reference mapping approach, we have developed a k-mer-based analysis pipeline (DiffKAP) to identify differentially expressed reads between RNA-Seq datasets without the requirement for a reference. We compared the DiffKAP approach with the traditional Tophat/Cuffdiff method using RNA-Seq data from soybean, which has a suitable reference genome. We subsequently examined differential gene expression for a coral meta-transcriptome where no reference is available, and validated the results using qRT-PCR. We conclude that DiffKAP is an accurate method to study differential gene expression in complex meta-transcriptomes without the requirement of a reference genome.

RevDate: 2018-11-28

Gagic M, Faville MJ, Zhang W, et al (2018)

Seed Transmission of Epichloë Endophytes in Lolium perenne Is Heavily Influenced by Host Genetics.

Frontiers in plant science, 9:1580.

Vertical transmission of symbiotic Epichloë endophytes from host grasses into progeny seed is the primary mechanism by which the next generation of plants is colonized. This process is often imperfect, resulting in endophyte-free seedlings which may have poor ecological fitness if the endophyte confers protective benefits to its host. In this study, we investigated the influence of host genetics and environment on the vertical transmission of Epichloë festucae var. lolii strain AR37 in the temperate forage grass Lolium perenne. The efficiency of AR37 transmission into the seed of over 500 plant genotypes from five genetically diverse breeding populations was determined. In Populations I-III, which had undergone previous selection for high seed infection by AR37, mean transmission was 88, 93, and 92%, respectively. However, in Populations IV and V, which had not undergone previous selection, mean transmission was 69 and 70%, respectively. The transmission values, together with single-nucleotide polymorphism data obtained using genotyping-by-sequencing for each host, was used to develop a genomic prediction model for AR37 seed transmission. The predictive ability of the model was estimated at r = 0.54. While host genotype contributed greatly to differences in AR37 seed transmission, undefined environmental variables also contributed significantly to seed transmission across different years and geographic locations. There was evidence for a small host genotype-by-environment effect; however this was less pronounced than genotype or environment alone. Analysis of endophyte infection levels in parent plants within Populations I and IV revealed a loss of endophyte infection over time in Population IV only. This population also had lower average tiller infection frequencies than Population I, suggesting that AR37 failed to colonize all the daughter tillers and therefore seeds. However, we also observed that infection of seed by AR37 may fail during or after initiation of floral development from plants where all tillers remained endophyte-infected over time. While the effects of environment and host genotype on fungal endophyte transmission have been evaluated previously, this is the first study that quantifies the relative impacts of host genetics and environment on endophyte vertical transmission.

RevDate: 2018-11-28

Mohammadi-Dehcheshmeh M, Niazi A, Ebrahimi M, et al (2018)

Unified Transcriptomic Signature of Arbuscular Mycorrhiza Colonization in Roots of Medicago truncatula by Integration of Machine Learning, Promoter Analysis, and Direct Merging Meta-Analysis.

Frontiers in plant science, 9:1550.

Plant root symbiosis with Arbuscular mycorrhizal (AM) fungi improves uptake of water and mineral nutrients, improving plant development under stressful conditions. Unraveling the unified transcriptomic signature of a successful colonization provides a better understanding of symbiosis. We developed a framework for finding the transcriptomic signature of Arbuscular mycorrhiza colonization and its regulating transcription factors in roots of Medicago truncatula. Expression profiles of roots in response to AM species were collected from four separate studies and were combined by direct merging meta-analysis. Batch effect, the major concern in expression meta-analysis, was reduced by three normalization steps: Robust Multi-array Average algorithm, Z-standardization, and quartiling normalization. Then, expression profile of 33685 genes in 18 root samples of Medicago as numerical features, as well as study ID and Arbuscular mycorrhiza type as categorical features, were mined by seven models: RELIEF, UNCERTAINTY, GINI INDEX, Chi Squared, RULE, INFO GAIN, and INFO GAIN RATIO. In total, 73 genes selected by machine learning models were up-regulated in response to AM (Z-value difference > 0.5). Feature weighting models also documented that this signature is independent from study (batch) effect. The AM inoculation signature obtained was able to differentiate efficiently between AM inoculated and non-inoculated samples. The AP2 domain class transcription factor, GRAS family transcription factors, and cyclin-dependent kinase were among the highly expressed meta-genes identified in the signature. We found high correspondence between the AM colonization signature obtained in this study and independent RNA-seq experiments on AM colonization, validating the repeatability of the colonization signature. Promoter analysis of upregulated genes in the transcriptomic signature led to the key regulators of AM colonization, including the essential transcription factors for endosymbiosis establishment and development such as NF-YA factors. The approach developed in this study offers three distinct novel features: (I) it improves direct merging meta-analysis by integrating supervised machine learning models and normalization steps to reduce study-specific batch effects; (II) seven attribute weighting models assessed the suitability of each gene for the transcriptomic signature which contributes to robustness of the signature (III) the approach is justifiable, easy to apply, and useful in practice. Our integrative framework of meta-analysis, promoter analysis, and machine learning provides a foundation to reveal the transcriptomic signature and regulatory circuits governing Arbuscular mycorrhizal symbiosis and is transferable to the other biological settings.

RevDate: 2018-11-29

Bauça JM (2018)

Reflections on the Mentor-Mentee Relationship: A Symbiosis.

EJIFCC, 29(3):230-233.

RevDate: 2018-11-27

Seró R, Núñez N, Núñez O, et al (2018)

Modified distribution in the polyphenolic profile of rosemary leaves induced by plant inoculation with an arbuscular mycorrhizal fungus.

Journal of the science of food and agriculture [Epub ahead of print].

BACKGROUND: Rosemary forms an arbuscular mycorrhizal (AM) symbiosis with a group of soilborne fungi belonging to the phylum Glomeromycota, which can modify the plant metabolome responsible for the antioxidant capacity and other health beneficial properties of Rosemary.

RESULTS: The effect of inoculating rosemary plants with an AM fungus on their growth via their polyphenolic fingerprinting was evaluated after analyzing leaf extracts from non-inoculated and inoculated rosemary plants by ultra-high performance liquid chromatography-high resolution mass spectrometry. . Plant growth parameters indicated that mycorrhizal inoculation significantly increased plant height and biomass. Chemical modifications in the plant polyphenolic profile distribution were found after a principal components analysis (PCA) loading plots study. Four compounds hosting strong antioxidant properties: ferulic acid, asiatic acid, carnosol, and vanillin were related to mycorrhizal rosemary plants while caffeic and chlorogenic acids had a higher influence in non-mycorrhizal plants.

CONCLUSION: Mycorrhization was found to stimulate growth in order to obtain a higher biomass of plant leaves in short time and avoiding chemical fertilization, while analytical results demonstrate that there is an alteration in the distribution of polyphenols in plants colonized by the symbiotic fungus, which can be related to an improvement in nutritional properties with future industrial significance. This article is protected by copyright. All rights reserved.

RevDate: 2018-11-27

Anheyer D, Kern C, Dobos G, et al (2018)

"I think you can achieve quite a lot if all of the staff stands behind it"-A qualitative study about the experience, knowledge and application of complementary therapies and integrative medicine in pediatrics.

Complementary therapies in medicine, 41:186-191.

BACKGROUND: In the United States there is an increasing use of complementary and alternative medicine (CAM) as well as integrative medicine (IM) in pediatrics. This study investigates the extent of knowledge and practical application of and attitudes towards the use and integration of CAM/IM therapies in two German pediatric clinics.

METHODS: A semi-standardized qualitative interview study was conducted in a rural children's hospital in Bavaria and in a children's clinic in the metropolitan area of Ruhr. Sixteen employees (7 nurses, 9 medical doctors, 68.8% female), who had volunteered through a local contact, were questioned during their shift on CAM/IM therapies. The data collected were analyzed with MAXQDA 12 using a qualitative technique for content analysis (by Mayring).

RESULTS: On average all respondents had little to superficial knowledge about the possibilities or evidence base of the therapies concerned, but did believe that CAM/IM could be an enhancement. In addition, many took interest in learning more about CAM/IM medical options. Nurses desired more practical and theoretical knowledge; while medical doctors focused on standardization and evidence base. All of them agreed that self-care strategies could enhance parental independence when treating symptoms of minor illnesses. They further agreed, that a symbiosis of conventional medicine and CAM/IM has great potential for patients and employees. It was stated that training of staff would be indispensable in order to implement standardized procedures.

CONCLUSIONS: There is great potential and interest in CAM/IM among pediatric care employees. Regardless of the challenges, this investigation did find that implementing CAM/IM might be a promising extension to the daily care routine.

RevDate: 2018-11-27

Almendras K, García J, Carú M, et al (2018)

Nitrogen-Fixing Bacteria Associated with Peltigera Cyanolichens and Cladonia Chlorolichens.

Molecules (Basel, Switzerland), 23(12): pii:molecules23123077.

Lichens have been extensively studied and described; however, recent evidence suggests that members of the bacterial community associated with them could contribute new functions to the symbiotic interaction. In this work, we compare the nitrogen-fixing guild associated with bipartite terricolous lichens with different types of photobiont: Peltigera cyanolichens and Cladonia chlorolichens. Since cyanobacteria contribute nitrogen to the symbiosis, we propose that chlorolichens have more diverse bacteria with the ability to fix nitrogen compared to cyanolichens. In addition, since part of these bacteria could be recruited from the substrate where lichens grow, we propose that thalli and substrates share some bacteria in common. The structure of the nitrogen-fixing guild in the lichen and substrate bacterial communities of both lichens was determined by terminal restriction fragment length polymorphism (TRFLP) of the nifH gene. Multivariate analyses showed that the nitrogen-fixing bacteria associated with both types of lichen were distinguishable from those present in their substrates. Likewise, the structure of the nitrogen-fixing bacteria present in the cyanolichens was different from that of chlorolichens. Finally, the diversity of this bacterial guild calculated using the Shannon index confirms the hypothesis that chlorolichens have a higher diversity of nitrogen-fixing bacteria than cyanolichens.

RevDate: 2018-11-26

Valdés-López O, Jayaraman D, Maeda J, et al (2018)

A Novel Positive Regulator of the Early Stages of the Root Nodule Symbiosis Identified by Phosphoproteomics.

Plant & cell physiology pii:5201344 [Epub ahead of print].

Signals and signaling pathways underlying the symbiosis between legumes and rhizobia have been studied extensively over the past decades. In a previous phosphoproteomic study on the Medicago truncatula - Sinorhizobium meliloti symbiosis, we identified plant proteins that are differentially phosphorylated upon the perception of rhizobial signals, called Nod factors. In this study, we provide experimental evidence that one of these proteins, Early Phosphorylated Protein 1 (EPP1), is required for the initiation of this symbiosis. Upon inoculation with rhizobia, MtEPP1 expression was induced in curled root hairs. Down-regulation of MtEPP1 in M. truncatula roots almost abolished calcium spiking, reduced the expression of essential symbiosis-related genes (MtNIN, MtNF-YB1, MtERN1, and MtENOD40), and strongly decreased nodule development. Phylogenetic analyses revealed that orthologs of MtEPP1 are present in legumes and specifically in plant species able to host arbuscular mycorrhizal fungi, suggesting a possible role in this association too. Short chitin oligomers induced the phosphorylation of MtEPP1 like Nod factors. However, the down-regulation of MtEPP1 affected the colonization of M. truncatula roots by arbuscular mycorrhizal fungi only moderately. Altogether, these findings indicate that MtEPP1 is essential for the establishment of the legume-rhizobia symbiosis but might plays a limited role in the arbuscular mycorrhizal symbiosis.

RevDate: 2018-11-26

Alonso D, Mancini MV, Damiani C, et al (2018)

Genome reduction in the mosquito symbiont Asaia.

Genome biology and evolution pii:5201038 [Epub ahead of print].

Symbiosis is now recognized as a driving force in evolution, a role that finds its ultimate expression in the variety of associations bonding insects with microbial symbionts. These associations have contributed to the evolutionary success of insects, with the hosts acquiring the capacity to exploit novel ecological niches, and the symbionts passing from facultative associations to obligate, mutualistic symbioses. In bacterial symbiont of insects, the transition from the free-living life style to mutualistic symbiosis often resulted in a reduction in the genome size, with the generation of the smallest bacterial genomes thus far described. Here we show that the process of genome reduction is still occurring in Asaia, a group of bacterial symbionts associated with a variety of insects. Indeed, comparative genomics of Asaia isolated from different mosquito species revealed a substantial genome size and gene content reduction in Asaia from Anopheles darlingi, a South-American malaria vector. We thus propose Asaia as a novel model to study genome reduction dynamics, within a single bacterial taxon, evolving in a common biological niche.

RevDate: 2018-11-30

Yang T, Cheng H, Wang H, et al (2018)

Comparative study of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) in corals, surrounding sediments and surface water at the Dazhou Island, China.

Chemosphere, 218:157-168 pii:S0045-6535(18)32170-2 [Epub ahead of print].

This study investigated polycyclic aromatic hydrocarbons (PAHs) content in corals (Acropora sp.), surficial sediments, and surface seawater, and heavy metals (HMs) contents in corals and sediments from Dazhou Island, Hainan, China. Concentrations of PAHs in seawater and sediment seasonally ranged from 191.5 ng L-1 to 587.7 ng L-1, and from 37.9 ng g-1 to 233 ng g-1, while levels in corals were higher (185.2-545.0 ng g-1) compared to those found in sediments, demonstrating bioaccumulation of PAHs by corals. A similar seasonally variation of PAHs was observed in water/sediments and corals, and the proportions of low molecular weight PAHs (LPAHs) in seawater and corals were higher. Pyrolytic and petrogenic contaminations were identified to be the main sources of PAHs. Lower HMs concentrations were detected in corals (9.8-39.4 μg g-1) than in sediments (65.0-83.3 μg g-1), but HMs bioaccumulation still occurs in corals. Higher concentrations of HMs in sediment and corals were detected in March and December, especially Mn and Zn. Application of an enrichment factor showed that Cu in corals was delivered from non-crustal materials, and anthropogenic inputs were possibly the main sources. According to Biota Sediment Accumulation Factor, corals could strongly bioaccumulate LPAHs and Cd, and PAHs at a higher (p < 0.05) rate than HMs. There was a lack of correlation between the accumulation of PAHs and HMs in corals based on the cluster analysis. Dual hierarchical clustering analysis result revealed that feeding, instead of symbiosis, might be the main process responsible for the bioaccumulation of PAHs and HMs.

RevDate: 2018-11-27

Doudoumis V, Augustinos A, Saridaki A, et al (2018)

Different laboratory populations similar bacterial profile? The case of Glossina palpalis gambiensis.

BMC microbiology, 18(Suppl 1):148 pii:10.1186/s12866-018-1290-9.

BACKGROUND: Microbiota plays an important role in the biology, ecology and evolution of insects including tsetse flies. The bacterial profile of 3 Glossina palpalis gambiensis laboratory colonies was examined using 16S rRNA gene amplicon sequencing to evaluate the dynamics of the bacterial diversity within and between each G. p. gambiensis colony.

RESULTS: The three G. p. gambiensis laboratory colonies displayed similar bacterial diversity indices and OTU distribution. Larval guts displayed a higher diversity when compared with the gastrointestinal tract of adults while no statistically significant differences were observed between testes and ovaries. Wigglesworthia and Sodalis were the most dominant taxa. In more detail, the gastrointestinal tract of adults was more enriched by Wigglesworthia while Sodalis were prominent in gonads. Interestingly, in larval guts a balanced co-existence between Wigglesworthia and Sodalis was observed. Sequences assigned to Wolbachia, Propionibacterium, and Providencia were also detected but to a much lesser degree. Clustering analysis indicated that the bacterial profile in G. p. gambiensis exhibits tissue tropism, hence distinguishing the gut bacterial profile from that present in reproductive organs.

CONCLUSIONS: Our results indicated that age, gender and the origin of the laboratory colonies did not significantly influence the formation of the bacterial profile, once these populations were kept under the same rearing conditions. Within the laboratory populations a tissue tropism was observed between the gut and gonadal bacterial profile.

RevDate: 2018-11-27

Augustinos AA, Meki IK, Demirbas-Uzel G, et al (2018)

Nuclear and Wolbachia-based multimarker approach for the rapid and accurate identification of tsetse species.

BMC microbiology, 18(Suppl 1):147 pii:10.1186/s12866-018-1295-4.

BACKGROUND: Tsetse flies (Diptera: Glossinidae) are solely responsible for the transmission of African trypanosomes, causative agents of sleeping sickness in humans and nagana in livestock. Due to the lack of efficient vaccines and the emergence of drug resistance, vector control approaches such as the sterile insect technique (SIT), remain the most effective way to control disease. SIT is a species-specific approach and therefore requires accurate identification of natural pest populations at the species level. However, the presence of morphologically similar species (species complexes and sub-species) in tsetse flies challenges the successful implementation of SIT-based population control.

RESULTS: In this study, we evaluate different molecular tools that can be applied for the delimitation of different Glossina species using tsetse samples derived from laboratory colonies, natural populations and museum specimens. The use of mitochondrial markers, nuclear markers (including internal transcribed spacer 1 (ITS1) and different microsatellites), and bacterial symbiotic markers (Wolbachia infection status) in combination with relatively inexpensive techniques such as PCR, agarose gel electrophoresis, and to some extent sequencing provided a rapid, cost effective, and accurate identification of several tsetse species.

CONCLUSIONS: The effectiveness of SIT benefits from the fine resolution of species limits in nature. The present study supports the quick identification of large samples using simple and cost effective universalized protocols, which can be easily applied by countries/laboratories with limited resources and expertise.


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.

21454 NE 143rd Street
Woodinville, WA 98077


E-mail: RJR8222@gmail.com

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.

Research Gate page for R J Robbins

ResearchGate is a social networking site for scientists and researchers to share papers, ask and answer questions, and find collaborators. According to a study by Nature and an article in Times Higher Education , it is the largest academic social network in terms of active users.

Curriculum Vitae for R J Robbins

short personal version

Curriculum Vitae for R J Robbins

long standard version

RJR Picks from Around the Web (updated 11 MAY 2018 )