Date of Award


Degree Type


Degree Name

Master of Science (MS)


Microbiology and Immunology


The pathogenic bacterium Staphylococcus aureus encounters a variety of immune cells that restrict bacterial growth and dissemination during infection. However, S. aureus counters these immune cell functions by producing myriad virulence factors that facilitate evasion of host defenses. Therefore, it is important to understand S. aureus-immune cell interactions and the virulence factors that perturb normal immune function to promote pathogenesis. In a genetic screen designed to identify S. aureus secreted factors that modulate macrophage activity our lab identified a transposon insertion mutant in the gene SAUSA300_1984, encoding a putative membrane spanning peptidase. To investigate the role of 1984 in pathogenesis, I generated a Δ1984 mutant and found it behaves like a quorum sensing system mutant, Δagr. The Agr system requires proper processing of a signaling peptide, AgrD, including cleavage of its N-terminus by an unknown peptidase. Given this information, I hypothesized that 1984 is a peptidase involved in processing AgrD.

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Available for download on Tuesday, June 14, 2022