Project description:The link between the gut microbiota and the human physiological state has been demonstrated in recent years. High gut microbiota diversity has been linked to many beneficial functions necessary or human health, while dysbiosis has been correlated to different pathological states. In this context, the study of the gut microbiota results of high relevance been necessary the development of different techniques capable of characterizing this complex ecosystem. Metaproteomics has been proved useful in the characterization of complex protein samples becoming a suitable tool for the study of these microbial communities. However, due to the complexity of these samples, protein extraction protocols may affect metaproteomics results. In this context, we evaluated stool sample processing (SSP) and microbial cell disruption, assessing the impact of different protocol modifications in the number of peptides and proteins identified. We compared different stool processing conditions and microbial cell disruption methods in terms of protein and peptide identifications and taxonomic profiles.
Project description:The link between the gut microbiota of a human being (a complex group of microorganism including not only bacteria but also fungi, viruses, etc.,) that form an ecosystem in his gastrointestinal tract and his physiological state is nowadays unquestionable. Metaproteomics has emerged as a useful technique to characterize this microbial community, not just taxonomically, but also focusing on specific biological processes carried out by gut microbiota that may have an effect in the host health or pathological state. In order to characterize this host-microbiota inter-relation, we carried out the metaproteomic study of 6 stool samples from 6 healthy adults. A total of 37 080 peptide sequences and 10 686 protein groups were identified in this study. Regarding taxonomic information, we found a total of 247 taxa among 105 were species. Interesting contributions of microbiota metabolism to human host physiology has also been described.
Project description:Stool metaproteomics of COVID-19 patients and healthy subjects to discover host and microbial protein alterations of gut ecosystem.
Project description:The adult human gut microbial community is typically dominated by two bacterial phyla (divisions), the Firmicutes and the Bacteroidetes. Little is known about the factors that govern the interactions between their members. Here we examine the niches of representatives of both phyla in vivo. Finished genome sequences were generated from E. rectale and E. eligens, which belong to Clostridium Cluster XIVa, one of the most common gut Firmicute clades. Comparison of these and 25 other gut Firmicutes and Bacteroidetes indicated that the former possess smaller genomes and a disproportionately smaller number of glycan-degrading enzymes. Germ-free mice were then colonized with E. rectale and/or a prominent human gut Bacteroidetes, Bacteroides thetaiotaomicron, followed by whole genome transcriptional profiling of both organisms in their distal gut (cecal) habitat as well as host responses, high resolution proteomic analysis of cecal contents, and biochemical assays of carbohydrate metabolism. B. thetaiotaomicron adapts to E. rectale by upregulating expression of a variety of polysaccharide utilization loci (PULs) encoding numerous glycoside hydrolase gene families, and by signaling the host to produce mucosal glycans that it, but not E. rectale, can access. E. rectale adapts to B. thetaiotaomicron by decreasing production of its glycan-degrading enzymes, increasing expression of selected amino acid and sugar transporters, and facilitating glycolysis by reducing levels of NADH, in part via generation of butyrate from acetate, which in turn is utilized by the gut epithelium. This simplified model of the human gut microbiota illustrates niche specialization and functional redundancy within members of major gut bacterial phyla, and the importance of host glycans as a nutrient foundation that ensures ecosystem stability. The interactions between E. rectale and B. thetaiotaomicron were characterized by performing whole genome transcriptional profiling of each species after colonization of gnotobiotic mice with each organism alone, or in combination. E. rectale was also profiled during in vitro growth.
Project description:Gut microbiota has profound effects on obesity and associated metabolic disorders. Targeting and shaping the gut microbiota via dietary intervention using probiotics, prebiotics and synbiotics can be effective in obesity management. Despite the well-known association between gut microbiota and obesity, the microbial alternations by synbiotics intervention, especially at the functional level, are still not characterized. In this study, we investigated the effects of synbiotics on high fat diet (HFD)-induced metabolic disorders, and systematically profiled the microbial profile at both the phylogenetic and functional levels. Synbiotics significantly reversed the HFD-induced change of microbial populations at the levels of richness, taxa and OTUs. Potentially important species Faecalibaculum rodentium and Alistipes putredinis that might mediate the beneficial effects of synbiotics were identified. At the functional level, short chain fatty acid and bile acid profiles revealed that interventions significantly restored cecal levels of acetate, propionate, and butyrate, and synbiotics reduced the elevated total bile acid level. Metaproteomics revealed the effect of synbiotics might be mediated through pathways involved in carbohydrate, amino acid, and energy metabolisms, replication and repair, etc. These results suggested that dietary intervention using our novel synbiotics alleviated HFD-induced weight gain and restored microbial ecosystem homeostasis phylogenetically and functionally.
Project description:The evolutional trajectory of gut microbial colonization from birth has been shown to prime for health later in life. Here, we combined cultivation-independent 16S rRNA gene sequencing and metaproteomics to investigate the functional maturation of gut microbiota in faecal samples from full-term healthy infants collected at 6 and 18 months of age. Phylogenetic analysis of the metaproteomes showed that Bifidobacterium provided the highest number of distinct protein groups. Considerable divergences between taxa abundance and protein phylogeny were observed at all taxonomic ranks. Age had a profound effect on early microbiota where compositional and functional complexity of less dissimilar communities increased with time. Comparisons of the relative abundances of proteins revealed the transition of taxon-associated saccharolytic and carbon metabolism strategies from catabolic pathways of milk and mucin-derived monosaccharides feeding acetate/propanoate synthesis to complex food sugars fuelling butyrate production. Furthermore, co-occurrence network analysis uncovered two anti-correlated modules of functional taxa. A low-connected Bifidobacteriaceae-centred guild of facultative anaerobes was succeeded by a rich club of obligate anaerobes densely interconnected around Lachnospiraceae, underpinning their pivotal roles in microbial ecosystem assemblies. Our findings establish a framework to visualize whole microbial community metabolism and ecosystem succession dynamics, proposing opportunities for microbiota-targeted health-promoting strategies early in life.
Project description:We have developed a microfluidics-based in vitro model of the human gut allowing co-culture of human and microbial cells and subsequent multi-omic assessment of the effect of the co-culture on the host transcriptome. We compare the transcriptional changes induced in the human epithelial cell line, Caco-2 after co-culture with Lactobacillus rhamnosus GG or a consortium of Lactobacillus rhamnosus GG and Bacteroides caccae.
Project description:The human gut microbiota impacts host metabolism and has been implicated in the pathophysiology of obesity and metabolic syndromes. However, defining the roles of specific microbial activities and metabolites on host phenotypes has proven challenging due to the complexity of the microbiome-host ecosystem. Here, we identify strains from the abundant gut bacterial phylum Bacteroidetes that display selective bile salt hydrolase (BSH) activity. Using isogenic strains of wild-type and BSH-deleted Bacteroides thetaiotaomicron, we selectively modulated the levels of the bile acid tauro-b-muricholic acid in monocolonized gnotobiotic mice. B. thetaiotaomicron BSH mutant-colonized mice displayed altered metabolism, including reduced weight gain and respiratory exchange ratios, as well as transcriptional changes in metabolic, circadian rhythm, and immune pathways in the gut and liver. Our results demonstrate that metabolites generated by a single microbial gene and enzymatic activity can profoundly alter host metabolism and gene expression at local and organism-level scales.
Project description:Morphine and its pharmacological derivatives are the most prescribed analgesics for moderate to severe pain management. However, chronic use of morphine reduces pathogen clearance and induces bacterial translocation across the gut barrier. The enteric microbiome has been shown to play a critical role in the preservation of the mucosal barrier function and metabolic homeostasis. Here, we show for the first time, using bacterial 16s rDNA sequencing, that chronic morphine treatment significantly alters the gut microbial composition and induces preferential expansion of the gram-positive pathogenic and reduction of bile-deconjugating bacterial strains. A significant reduction in both primary and secondary bile acid levels was seen in the gut, but not in the liver with morphine treatment. Morphine induced microbial dysbiosis and gut barrier disruption was rescued by transplanting placebo-treated microbiota into morphine-treated animals, indicating that microbiome modulation could be exploited as a therapeutic strategy for patients using morphine for pain management. In this study, we establish a link between the two phenomena, namely gut barrier compromise and dysregulated bile acid metabolism. We show for the first time that morphine fosters significant gut microbial dysbiosis and disrupts cholesterol/bile acid metabolism. Changes in the gut microbial composition is strongly correlated to disruption in host inflammatory homeostasis13,14 and in many diseases (e.g. cancer/HIV infection), persistent inflammation is known to aid and promote the progression of the primary morbidity. We show here that chronic morphine, gut microbial dysbiosis, disruption of cholesterol/bile acid metabolism and gut inflammation; have a linear correlation. This opens up the prospect of devising minimally invasive adjunct treatment strategies involving microbiome and bile acid modulation and thus bringing down morphine-mediated inflammation in the host.