Project description:Here we have shown that diet-mediated alterations of the gut microbiota composition cause an erosion of the colonic mucus barrier. A compensatory increase in cellular mucus production by the host is not sufficient to re-establish the barrier, possibly due to a lacking increase in mucus secretion. While microbial transplant from mice fed a fiber-rich diet can prevent the mucus defects, the mechanism seems to be independent of general fiber fermentation and rather depend on distinct bacterial species and/or their metabolites.
2017-12-22 | PXD006129 | Pride
Project description:Single Batch Fermentation System Simulating Human Colonic Microbiota_Ulcerative colitis
| PRJEB28848 | ENA
Project description:The Colonic fermentation and bacterial community in weaned lambs
Project description:Degradation of complex dietary fibers by gut microbes is essential for colonic fermentation, short-chain fatty acid production, and microbiome function. Ruminococcus bromii is the primary resistant starch (RS) degrader in humans, which relies on the amylosome, a specialized cell-bound enzymatic complex. To unravel its structure-function relationship and the interplay among its components, we applied an holistic multilayered approach and found that amylosome combinatorics, resistant starch degradation and enzymatic synergy are regulated at two levels: structural constraints enforcing enzyme proximity and expression-driven shifts in enzyme proportions. Cryo-electron tomography revealed that the amylosome comprises a constitutive extracellular layer extending toward the RS. However, proteomics demonstrated its remodeling across different growth conditions, with Amy4 and Amy16 comprising 60% of the amylosome in response to RS. Structural and biochemical analyses revealed complementarity and synergistic RS degradation by these enzymes, which allow R. bromii to fine-tune its adaptation to dietary fiber and shape colonic metabolism
2025-11-02 | PXD060149 | Pride
Project description:16S rRNA sequencing of FOS-treated colonic microbiota fermentation products
Project description:Butyrate is a four-carbon short-chain fatty acid produced from microbial fermentation of dietary fibers present at high millimolar concentrations in the colonic lumen.However, in an intact epithelium, macrophages residing in the lamina propria areexposed to only sub-millimolar butyrate concentrations. Current studies show antiinflammatoryproperties of butyrate and suggest that it might have therapeuticapplications in inflammatory bowel disease and colonic cancer. We now show that theeffect of butyrate on human macrophages is strongly concentration dependent. At lowconcentrations (0.1–1 mM), butyrate suppresses LPS-induced production ofproinflammatory cytokines potentially through a combination PPAR-γ signaling andincreased histone acetylation. At high concentrations (10 mM), butyrate promotesproduction of inflammatory cytokines in a mechanism that involves G protein-coupledreceptor GPR109A, the lipid transporter CD36, and the kinase SRC. We propose thatbutyrate is a crucial signaling molecule for intestinal integrity, since intestinaldisruption exposes macrophages to high butyrate concentrations.