SUMMARY CORE B: Genetics Core for Mucin Degrading Bacteria The intestinal microbiota comprises diverse bacteria, a subset of which are capable of degrading the host-derived mucins that are a primary component of the intestinal mucus layer. Excessive erosion of the mucus layer is linked to poor health outcomes in many contexts, including patients undergoing hematopoietic stem cell transplant, where it is associated with the development of neutropenic fever. As an essential component of the P01, we will develop a Genetics Core for Mucin Degrading Bacteria. The Core will support the three related projects in investigating the mechanisms and regulation of mucin degradation by the prevalent mucin degraders Akkermansia and Bacteroides spp. Our lab has specialized expertise in the genetic manipulation of these strictly anaerobic bacteria and contributed to developing the first set of genetic tools for Akkermansia. The primary functions of the Core will be to: (1) generate mutants in bacterial isolates and apply high-throughput genetic screens, (2) provide mutants in specific genes of interest and engineer strains for recombinant protein expression, (3) provide analysis of mucin degradation using fluorescently labelled glycans as well as human colonic mucin reagent, and (4) support bioinformatic analysis of metagenomic sequencing data, including strain identification and comparative genomics, as well as provide access to external glycan expertise. We will combine the results from the individual projects to develop a database of mucin degrading enzymes that will serve as a resource to the research community. By providing strains and reagents to gain a mechanistic understanding of bacterial mucin degradation, the proposed Core will be integral to the three proposed projects