Studying the dynamics of the gut microbiota using metabolically stable isotopic labeling and metaproteomics.

Background: The gut microbiome and its metabolic processes are dynamic systems. Surprisingly, our understanding of gut microbiome dynamics is limited. Here we report a metaproteomic workflow that involves protein stable isotope probing (protein-SIP) and identification and quantification of partially labeled peptides. We also developed a package, which we call MetaProfiler, that corrects for false identifications and performs phylogenetic and time series analysis for the study of gut microbiome functional dynamics. Results: From the stool sample of five mice that were fed with 15N hydrolysate from Ralstonia eutropha, we identified 15,297 non-redundant unlabeled peptides of which 10,839 of their heavy counterparts were quantified. These peptides revealed incorporation profiles over time that were different between and within taxa, as well as between and within clusters of orthologous groups (COGs). Conclusions: Our study helps unravel the complex dynamics of protein synthesis and bacterial dynamics in the mouse microbiome. Availability: MetaProfiler and the bioinformatic pipeline are available at https://github.com/psmyth94/MetaProfiler.git.