Project description:The rate, timing, and mode of species dispersal is recognized as a key driver of the structure and function of communities of macroorganisms, and may be one ecological process that determines the diversity of microbiomes. Many previous studies have quantified the modes and mechanisms of bacterial motility using monocultures of a few model bacterial species. But most microbes live in multispecies microbial communities, where direct interactions between microbes may inhibit or facilitate dispersal through a number of physical (e.g., hydrodynamic) and biological (e.g., chemotaxis) mechanisms, which remain largely unexplored. Using cheese rinds as a model microbiome, we demonstrate that physical networks created by filamentous fungi can impact the extent of small-scale bacterial dispersal and can shape the composition of microbiomes. From the cheese rind of Saint Nectaire, we serendipitously observed the bacterium Serratia proteamaculans actively spreads on networks formed by the fungus Mucor. By experimentally recreating these pairwise interactions in the lab, we show that Serratia spreads on actively growing and previously established fungal networks. The extent of symbiotic dispersal is dependent on the fungal network: diffuse and fast-growing Mucor networks provide the greatest dispersal facilitation of the Serratia species, while dense and slow-growing Penicillium networks provide limited dispersal facilitation. Fungal-mediated dispersal occurs in closely related Serratia species isolated from other environments, suggesting that this bacterial-fungal interaction is widespread in nature. Both RNA-seq and transposon mutagenesis point to specific molecular mechanisms that play key roles in this bacterial-fungal interaction, including chitin utilization and flagellin biosynthesis. By manipulating the presence and type of fungal networks in multispecies communities, we provide the first evidence that fungal networks shape the composition of bacterial communities, with Mucor networks shifting experimental bacterial communities to complete dominance by motile Proteobacteria. Collectively, our work demonstrates that these strong biophysical interactions between bacterial and fungi can have community-level consequences and may be operating in many other microbiomes.
2017-08-02 | GSE85095 | GEO
Project description:Taxonomic studies of bacterial strains isolated on Beach Getbul (tidal flats)
Project description:Investigation of mRNA expression (using HiSeq 2500) in response to treatment of Daphnia magna to pyriproxyfen, wetland water, or stormwater samples.
Project description:In this study we have analysed the regulation of miRNA in bone marrow derived macrophages in response to the fungal pathogen heat killed Candida albicans and bacterial cell wall component, LPS. The aim of the study was to identify and validate miRNAs involved in the innate immune system in response to fungal and bacterial stimuli and investigate potential mechanisms for their transcription.
Project description:Background: Idiopathic Chronic Diarrhea (ICD) is a common cause of morbidity and mortality among juvenile rhesus macaques. Characterized by chronic inflammation of the colon and repeated bouts of diarrhea, ICD is largely unresponsive to medical interventions including corticosteroid, antiparasitic and antibiotic treatments. Although ICD is accompanied by large disruptions in the composition of the commensal gut microbiome, no single pathogen has been concretely identified as responsible for the onset and continuation of the disease. Results: Fecal samples were collected from twelve ICD-diagnosed macaques and twelve age and sex-matched controls. RNA was extracted for metatranscriptomic analysis of species and activity within the gut microbiome. Using SAMSA2, these samples were contrasted to identify shifts both in overall organism activity and functional activity. Bacterial, fungal, archaeal, protozoan, and macaque (host) transcripts were simultaneously assessed. ICD-afflicted animals were characterized by increased activity of known bacterial pathogens and by decreased activity of archaeal methanogens. Interestingly, known fungal opportunists were not increased in ICD, nor were the usual enteric protozoans, although Trichomonas activity is up-regualted. Known mucin degrading organisms and mucin-degrading enzymes were up-regulated in the fecal microbiomes of ICD-afflicted animals. Assessment of colon sections using immunohistochemistry confirmed differential mucin composition between healthy control and ICD animals. Finally, assessment of host-derived transcripts confirms colonic inflammation and suggests that the lumen is infiltrated by granulocytes. Conclusions: The simultaneous profiling of bacterial, fungal, archaeal, protozoan, and macaque transcripts from stool samples suggests that ICD of rhesus macaques is associated with increased pathogen activity and altered mucin degradation.
2019-03-09 | GSE108572 | GEO
Project description:investigate tidal flow constructed wetland microbial community diversity