Heterogeneity in bacterial quorum sensing during infection

PROJECT SUMMARY All animals depend on bacterial symbionts for specific traits that promote their fitness. The mechanisms by which hosts acquire and select for those symbionts remains unclear but important to develop new strategies and therapeutics based on bacteria to improve host health. The symbiosis established between the Hawaiian bobtail squid and the bioluminescent bacterium Vibrio fischeri is a powerful model to examine the molecular mechanisms that promote symbiont assembly and colonization in a host. This supplement seeks support to collect and maintain a cohort of squid to complete studies associated with the main project that were adversely affected by a critical life event involving the project PI. The proposed activities will 1) determine the extent of expression of a small regulatory RNA within host-associated bacteria, and 2) determine how the import of a host-derived sulfur source impacts V. fischeri physiology in vivo. Squid colonization assays with defined bacterial mutants will address each research question, thereby completing two studies. Together, these experiments will provide knowledge of how V. fischeri cells are acquired and acclimate to the squid host environment, which is insight that will increase understanding of how bacterial symbionts successfully establish symbiosis with a host.