Jeremy Ellermeier, Ph.D.

Salmonella species cause a range of diseases, from self-limiting gastroenteritis to life-threatening systemic infections, in a variety of hosts. The CDC estimates that non-typhoid Salmonella species cause 1.2 million cases of foodborne illness and 450 deaths per year in the United States alone. Salmonella enterica serovar Typhimurium is a leading cause of gastroenteritis worldwide and is used as a model for human typhoid fever in mice. The twin arginine translocation system (Tat) is a protein secretion system that is conserved in bacteria, archaea, and plants. In gram-negative bacteria, it is required for the export of substrate proteins from the cytoplasm to the periplasm of the organism. Tat substrates must be properly folded prior to export to the periplasm. In Salmonella , there are 30 proteins that are substrates of Tat, among these are hydrogenases and cell wall amidases. We have demonstrated that increasing concentrations of bile salts induce expression of a tatABC-lacZ fusion. We also have found that deletions of tatABC are more sensitive than wild type to peptidoglycan targeting antibiotics. These findings lead to several questions: What is the mechanism of bile activation of tat expression? What promoter elements are important for expression of tatABC ? Why is the tatABC deletion more susceptible to ampicillin? Research in the Ellermeier lab uses bacterial genetics to study these and other questions in Salmonella Typhimurium.
Microbiology
Bacterial Genetics
Antibiotic Resistance