Our laboratory is interested in bacterial metabolism and physiology. Much of the work we do is performed in Salmonella enterica because we can do sophisticated genetic analyses of strains. We are currently focused on three areas of research. First, we study metabolic pathway integration. We identified the cobB gene of Salmonella enterica as a new member of the SIR2 family regulatory proteins in eukaryotes whose activities are needed for gene silencing and cell aging. Our report was an important contribution to this field of research and led to the identification of two enzymatic activities associated with these proteins. We also established a link between sirtuins and central metabolism, and have established a role for the sirtuin-dependent acylation/deacylation system is in maintaining coenzyme A homeostasis. A second focus of our work centers on the catabolism of poor carbon sources such as propionate and acetate, two short-chain fatty acids that are very abundant in soil and the gut. We are interested in identifying and dissecting the function of processes used by the cell to avoid the toxic effects of propionate and acetate. The third area of research is to study complex metabolic pathway analysis. We are studying multiple aspects of adenosylcobalamin (AdoCbl, coenzyme B12) biosynthesis. In Salmonella enterica, de novo synthesis of AdoCbl occurs only under anoxic growth conditions. We have discovered new enzymes and pathways in archaea for the assimilation of incomplete corrinoids from the environment.

• Microbiology 303: Biology of Microorganisms

• Trainer, Biotechnology Graduate Training Program
• Chemistry Biology Interface Training Program
• Molecular Biosciences Training Program
• Microbiology Doctoral Training Program