Project description:The increased prevalence of Salmonella spp. resistance in swine spurs the search for alternatives to antibiotics. Microcin J25 (MccJ25), a bacteriocin produced by Escherichia coli, is a potent inhibitor of several pathogenic bacteria including Salmonella enterica. In this study, we aimed to evaluate in vitro the impact of MccJ25 on the metabolic activity of the swine colonic microbiota. The PolyFermS in vitro continuous fermentation model was used with modified Macfarlane medium to simulate the porcine proximal colon. During 35 days of fermentation, a first-stage reactor containing immobilized swine fecal microbiota fed two second-stage control and test reactors operated in parallel and used to test the effectsof MccJ25 on the composition and the metabolic activity of the microbiota. Reuterin, a broad spectrum antimicrobial produced by Limosilactobacillus reuteri and the antibiotic rifampicin were tested for comparison. LC-MS analysis of the cell extracts was used to assess the bacteriocin/antibiotic degradation products and monitor changes in the swine colonic microbiota metabolome.
Project description:Age-dependent changes of the gut-associated microbiome have been linked to increased frailty and systemic inflammation. This study found that age-associated changes of the gut microbiome of BALB/c and C57BL/6 mice could be reverted by co-housing of aged (22 months old) and adult (3 months old) mice for 30-40 days or faecal microbiota transplantation (FMT) from adult into aged mice. This was demonstrated using high-throughput sequencing of the V3-V4 hypervariable region of bacterial 16S rRNA gene isolated from faecal pellets collected from 3-4 months old adult and 22-23 months old aged mice before and after co-housing or FMT.
Project description:A phylogenetic microarray targeting 66 families described in the human gut microbiota has been developped aud used to monitor the gut microbiota's structure and diversity. The microarray format provided by Agilent and used in this study is 8x15K. A study with a total of 4 chips was realized. Arrays 1 and 2: Hybridization with 100ng of labelled 16S rRNA gene amplicons from a mock community sample and 250ng of labelled 16S rRNA gene amplicons from 1 faecal sample. Each Agilent-030618 array probe (4441) was synthetized in three replicates. Arrays 3 and 4: Hybridization with 250ng of labelled 16S rRNA gene amplicons from 2 faecal samples. Each Agilent-40558 array probe (4441) was synthetized in three replicates.
Project description:The intestinal microbiota plays a key role in shaping host homeostasis by regulating metabolism, immune responses and behaviour. Its dysregulation has been associated with metabolic, immune and neuropsychiatric disorders and is accompanied by changes in bacterial metabolic regulation. Although proteomic is well suited for analysis of individual microbes, metaproteomic of faecal samples is challenging due to the physical structure of the sample, presence of contaminating host proteins and coexistence of hundreds of species. Furthermore, there is a lack of consensus regarding preparation of faecal samples, as well as downstream bioinformatic analyses following metaproteomic data acquisition. Here we assess sample preparation and data analysis strategies applied to mouse faeces in a typical LC-MS/MS metaproteomic experiment. We show that low speed centrifugation (LSC) of faecal samples leads to high protein identification rates but possibly enriched for a subset of taxa. During database search, two-step search strategies led to dramatic and underestimated accumulation of false positive protein identifications. Regarding taxonomic annotation, the MS-identified peptides of unknown origin were annotated with highest sensitivity and specificity using the Unipept software. Comparison of matching metaproteome and metagenome data revealed a positive correlation between protein and gene abundances. Notably, nearly all functional categories of detected protein groups were differentially abundant in the metaproteome compared to what would be expected from the metagenome, highlighting the need to perform metaproteomic when studying complex microbiome samples.
Project description:We compared the microbiota of paired mouse caecal contents and faeces by applying a multi-omic approach, including 16S rDNA sequencing, shotgun metagenomics, and shotgun metaproteomics. The aim of the study was to verify whether faecal samples are a reliable proxy for the mouse colonic luminal microbiota, as well as to identify changes in taxonomy and functional activity between caecal and faecal microbial communities, which have to be carefully considered when using stool as sample for mouse gut microbiota investigations.
