Project description:This study aimed to characterise the transcriptomic response of the lactate-utilizing bacteria, Coprococcus catus and Anaerobutyricum soehngenii, grown on varying carbon sources. This work has allowed for identification of divergent gene clusters in each species contributing to the lactate utilisation pathway.
Project description:Sodium oligomannate (GV-971), an oligosaccharide drug approved in China for treating mild-to-moderate Alzheimer's disease (AD), was previously found to recondition the gut microbiota and limit altered peripheral Th1 immunity in AD transgenic mice. As a follow-up study, we here provide advances by pinpointing a Lactobacillus murinus strain that highly expressed a gene encoding a putative adhesin containing Rib repeats (Ribhigh-L.m.) that was particularly enriched in 5XFAD transgenic mice. Mechanistically, Ribhigh-L.m. adherence to the gut epithelia upregulated fecal metabolites, among which lactate ranked as the top candidate. Lactate stimulated the epithelial production of serum amyloid A (SAA) in gut via GPR81-NFκB axis, contributing to peripheral Th1 activation. Moreover, GV-971 disrupted the adherence of Ribhigh-L.m. to gut epithelia via directly binding to Rib, leading to the reduced SAA and alleviated Th1-skewed inflammation. These findings were replicated in early-staged AD patients. Together, we gained further insights between gut bacteria and AD progression and the mechanism of GV-971 in treating AD.
Project description:Human milk oligosaccharides (HMOs) function as prebiotics for beneficial bacteria in the developing gut, often dominated by Bifidobacterium spp. To understand the relationship between Bifidobacterium utilizing HMOs and how the metabolites that are produced could affect the host, we analyzed the metabolism of HMO 2’-fucosyllactose (2’-FL) in Bifidobacterium longum ssp. infantis Bi-26. RNA-seq and metabolite analysis (NMR/GCMS) was performed on samples at early (A600=0.25), mid-log (0.5-0.7) and late-log phases (1.0-2.0) of growth. Transcriptomic analysis revealed many gene clusters including three novel ABC-type sugar transport clusters to be upregulated in Bi-26 involved in processing of 2’-FL along with metabolism of its monomers glucose, fucose and galactose. Metabolite data confirmed the production of formate, acetate, 1,2-propanediol, lactate and cleaving of fucose from 2’-FL. The formation of acetate, formate, and lactate showed how the cell uses metabolites during fermentation to produce higher levels of ATP (mid-log compared to other stages) or generate cofactors to balance redox. We concluded 2’-FL metabolism is a complex process involving gene clusters throughout the genome producing more metabolites compared to lactose. These results provide valuable insight on the mode-of-action of 2’-FL utilization by Bifidobacterium longum ssp. infantis Bi-26.
Project description:Approximately 15% of US adults have circulating levels of uric acid above its solubility limit, which is causally linked to the inflammatory disease gout. In most mammals, uric acid elimination is facilitated by the enzyme uricase. However, human uricase is a pseudogene, having been inactivated early in hominid evolution. Though it has long been known that a substantial amount of uric acid is eliminated in the gut, the role of the gut microbiota in hyperuricemia has not been studied. Here we identify a gene cluster, widely distributed in the gut microbiome, that encodes a pathway for uric acid degradation. Stable isotope tracing demonstrates that gut bacteria metabolize uric acid to xanthine or short chain fatty acids such as acetate, lactate and butyrate. Ablation of the microbiota in uricase-deficient mice causes profound hyperuricemia, and anaerobe-targeted antibiotics increase the risk of gout in humans. These data reveal a role for the gut microbiota in uric acid excretion and highlight the potential for microbiome-targeted therapeutics in hyperuricemia.
Project description:This clinical trial hypothesize that Gut Microbiota (bacteria, viruses, fungi)play a major role in the occurrence and progression of many chronic gastrointestinal diseases like Irritable Bowel Syndrome, Inflammatory Bowel Diseases and Colo-Rectal Cancer.
Hence, aims to study the spectrum of such microbiota in these patients as compared to normal subjects, by utilizing metagenomic techniques rather than cultural methods.
Project description:Background: Probiotic-like bacteria treatment has been described to be associated with gut microbiota modifications. Goal: To decipher if the effects of the tested probiotic-like bacteria are due to the bacteria itself or due to the effects of the bacteria on the gut microbiota. Methodology: In this study, gut microbiota has been analyzed from feces samples of subjects with metabolic syndrome and treated with one of the 2 tested probiotic-like bacteria or with the placebo during 3months.
Project description:This SuperSeries is composed of the following subset Series: GSE25572: Depolymerization of plant cell wall glycans by symbiotic human gut bacteria (Bacteroides thetaiotaomicron) GSE25575: Depolymerization of plant cell wall glycans by symbiotic human gut bacteria (Bacteroides ovatus) Refer to individual Series
