Degree Name

MS (Master of Science)



Date of Award


Committee Chair or Co-Chairs

Erik Petersen

Committee Members

Thomas Jones, Sean Fox


Regulation of the bacterial second messenger cyclic-di-GMP in Salmonella Typhimurium allows it to delicately alter phenotypes to optimize invasion and survive intracellularly in epithelial cells and macrophages to become virulent and cause infection. Cyclic-di-GMP concentration is regulated by the presence of external stimuli, sensory diguanylate cyclases (DGCs) and phosphodiesterases (PDEs), and cyclic-di-GMP binding effectors. Previous studies established that maintenance of low cyclic-di-GMP concentrations is required for survival in macrophages, and that deletion of 3 active PDEs reduces this survival. Here I showed that these 3 PDEs also influenced the infection of epithelial cells. Further studies re-established the decreased survival in an immortalized macrophage cell line and determined that cyclic-di-GMP-binding cellulose synthase BcsA was responsible for the decreased survival in macrophages. Finally, I also identified an active DGC whose deletion within the 3xKO restores survival levels, suggesting that this enzyme is responsible for the synthesis of cyclic-di-GMP during macrophage infection.

Document Type

Thesis - embargo


Copyright by the authors.

Available for download on Saturday, June 15, 2024