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Philip Kaseska ACF Abstract FY12

"Analysis of a Cyclic Peptide Library to Identify Proteins That Effect hiA Expression and Invasion in Salmonella enterica serovar Typhimurium"

Conference Name: Midwest Microbial Pathogenesis Conference

Salmonella enterica serovar Typhimurium is a gram-negative bacterium that produces a self-limiting, localized gastroenteritidis in humans upon ingestion of contaminated food or water. Pathogenesis demands Salmonella recognition of multiple environmental conditions which activate a 40 kb region of DNA known as Salmonella Pathogenicity Island 1 (SPI-1). The expressed SPI-1 proteins manipulate normal host cell function and direct the uptake of the bacteria into targeted cells. The expression of the SPI-1 genes is controlled via the sensing of various environmental conditions through multiple pathways. When conditions are optimal for invasion, these various inducing signals are directed toward the SPI-1 transcriptional activator hilA. In collaboration with Brad Jones at the University of Iowa, we have acquired a plasmid library that produces small random cyclic peptides. Currently we have identified some plasmids which reduce expression of a hilA::lacZY reporter in E. coli and in Salmonella Typhimurium. The effects of these plasmids have also been quantified through in vivo invasion assays.