Project description:Endogenous intestinal microbiota have wide-ranging and largely uncharacterized effects on host physiology. Here, we used reverse-phase liquid chromatography-coupled tandem mass spectrometry to define the mouse intestinal proteome in the stomach, jejunum, ileum, cecum, and proximal colon under three colonization states: germ-free, monocolonized with Bacteroides thetaiotaomicron, and conventionally raised. Our analysis revealed distinct proteomic abundance profiles along the gastrointestinal tract. Unsupervised clustering showed that host protein abundance primarily depended on gastrointestinal location rather than colonization state and specific proteins and functions that defined these locations were identified by random forest classifications. K-means clustering of protein abundance across locations revealed substantial differences in host protein production between conventionally raised mice relative to germ-free and monocolonized mice. Finally, comparison to fecal proteomic datasets suggested that the identities of stool proteins are not biased to any region of the gastrointestinal tract, but are substantially impacted by the microbiota in the distal colon.
Project description:To describe the protein profile in hippocampus, colon and ileum tissue’ changing after the old faeces transplants, we adopted a quantitative label free proteomics approach.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.
Project description:The gastrointestinal tract is covered by a single layer of epithelial cells that, together with the mucus layers, protect the underlying tissue from bacterial invasion. The epithelium has one of the highest turnover rates in the body, renewing every 4-5 days. Using stable isotope labelling, high-resolution mass spectrometry and computational analysis, we report here a comprehensive dataset of the turnover rate of 3041 and the expression of 5012 intestinal epithelial cell proteins, analyzed under conventional and germ-free conditions across five different segments in mouse intestine. The median protein half-life was shorter in small intestine compared to colon, ranging from 3.5 to 4.2 days. Differences in protein turnover rates along the intestinal tract can be explained by distinct physiological functions and site-specific immune responses between the small and large intestine. Absence of microflora resulted in increased protein half-life by approximately one day.