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John Gunn, PhD


Professor, Molecular Virology, Immunology, and Medical Genetics
Department of Internal Medicine
Center for Microbial Interface Biology

1006 BRT
460 W. 12th Avenue
Columbus, Ohio 43210
Phone: (614) 292-6036
Gunn.43@osu.edu

Dr. Gunn joined the faculty in July 2003.

Special Interests

Dr. Gunn's laboratory is primarily interested in the molecular mechanisms used by Salmonella spp. to survive harsh conditions it encounters within the human host. Salmonellae encounter numerous anatomic sites during infection, including the inhospitable environment of the macrophage phagosome, where they are able to survive and replicate. Present within host phagocytes (and at mucosal surfaces) are a potent group of cytotoxic agents, antimicrobial peptides (AP). The PmrA-PmrB two-component regulatory system is activated when Salmonella are within host macrophages, and is necessary for resistance to AP, which involves modifications of the LPS that decrease peptide binding. He is focused on studies of the PmrA-PmrB regulon, including: (1) identification and characterization of PmrA-PmrB regulated genes necessary for AP resistance and LPS modification; (2) defintion of the biochemical pathway of LPS modification, and (3) determination of the role of PmrA-PmrB mediated LPS modifications in Salmonella virulence.

Bile salts are detergents made by the liver that are stored in the gallbladder and released into the intestine to aid digestion. Salmonella spp. come in contact with bile salts in the intestine, and in the chronic carrier state, within the gallbladder. Salmonella is able to resist the action of bile and respond to escalating bile concentrations by increasing mechanisms of resistance. He is currently trying to understand: (1) how Salmonella is able to sense bile, (2) what mechanisms of bile resistance exist in Salmonella, and (3) how biofilm formation on gallstones may aid in development of the carrier state.

Finally, Dr. Gunn's laboratory is interested in pathogenesis and intramacrophage survival of the Category A biodefense agent, Francisella tularensis. This work involves the identification of genes required for survival against both oxygen dependent and oxygen independent killing within phagocytes, as well as genes induced in this intracellular environment.

Links

Curriculum Vitae

Center for Microbial Interface Biology