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Virulence

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Role Of Branched-Chain Amino Acid Transporters In Staphylococcus Aureus Virulence, Sameha Omer Aug 2013

Role Of Branched-Chain Amino Acid Transporters In Staphylococcus Aureus Virulence, Sameha Omer

Electronic Thesis and Dissertation Repository

Branched-chain amino acids (BCAAs) act as effector molecules that signal a global transcriptional regulator, CodY, to regulate virulence factors in nutrient depleted environments. Staphylococcus aureus contains three putative BCAA transporters (BrnQ1, BrnQ2, BrnQ3) whose role in BCAA uptake is unknown. We hypothesize that BrnQ transporters are involved in BCAA uptake and contribute to virulence in S. aureus by modulating CodY activity. Results from radioactive uptake assays indicate that BrnQ1 is the predominant BrnQ transporter of isoleucine, valine and leucine. Meanwhile, BrnQ2 is more specific for isoleucine. Furthermore, only the lack of BrnQ1 hinders growth of S. aureus in chemically-defined media …


Staphylococcus Aureus Response To Long Chain Antimicrobial Fatty Acids, Benjamin Arsic Sep 2012

Staphylococcus Aureus Response To Long Chain Antimicrobial Fatty Acids, Benjamin Arsic

Electronic Thesis and Dissertation Repository

Staphylococcus aureus is a common pathogen that has the ability to infect virtually every tissue and organ system of the body. Despite its propensity to cause invasive infection, S. aureus is also a commensal organism, asymptomatically colonizing ~25% of the population. Much research has gone into resolving this paradox, focusing on both human and bacterial factors that may contribute to colonization. Antimicrobial fatty acids present on the skin and in the nasal mucosa are important components of the innate immune system, and thus we undertook to further understand how S. aureus responds to these fatty acids, and how this response …