PROJECT SUMMARY Infection with the bacterial pathogen Salmonella enterica serovar Typhimurium (S. Tm) is a common cause of inflammatory diarrhea. Intriguingly, intestinal inflammation drives an expansion of the S. Tm population in the gut lumen. The molecular mechanisms that support S. Tm colonization of the intestinal tract remain incompletely understood. Our central hypothesis is that the inflamed gut constitutes a peculiar nutritional environment that enables S. Tm to outgrow obligate anaerobic commensal bacteria. In this application, we will investigate how inflammatory reactive oxygen and nitrogen species are generating a diverse array of inflammation-associated small metabolites. We hypothesize that reactive oxygen and nitrogen species oxidize sugars to smaller mono- and dicarboxylic acids such as glutarate, which serve as nutrients for S. Tm to support gut colonization. We will test key aspects of our hypothesis in mouse models of infection and in vitro. We will pursue the following specific aims: 1.) Determine whether glutarate and other carboxylic acids are generated as byproducts of RNS metabolism, and 2. Investigate S. Tm glutarate metabolism in the context of infection. This work will advance our understanding of how intestinal pathogens, such as S. Tm, adapt their carbon and energy metabolism to colonize the mammalian intestinal tract. These studies are also expected to advance our understanding of how reactive oxygen and nitrogen species participate in diversity-generating reactions that shape the metabolite landscape during gut inflammation.