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Full-Text Articles in Genetics and Genomics
Characterization Of Staphylococcus Aureus Lipase, Vithooshan Vijayakumaran
Characterization Of Staphylococcus Aureus Lipase, Vithooshan Vijayakumaran
Electronic Thesis and Dissertation Repository
USA300, a strain of community-associated methicillin resistant Staphylococcus aureus (CA-MRSA), has become prevalent in the community. Colonization of human skin requires mechanisms that allow this bacterium to overcome the innate immune defenses on the skin, including secretion of antimicrobial lipids. Antimicrobial lipids inhibit S. aureus growth and induce the staphylococcal proteolytic cascade, producing aureolysin (Aur) which processes the lipase glycerol ester hydrolase (Geh). Nearly all S. aureus strains secrete Geh, yet little information exists concerning its function. Using purified Aur and Geh we confirm that aureolysin processes proGeh to Geh. We then confirmed that geh was required for lipase activity …
Role Of Branched-Chain Amino Acid Transporters In Staphylococcus Aureus Virulence, Sameha Omer
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 …
Cellular Adaptation Of Macrophages To Anthrax Lethal Toxin-Induced Pyroptosis Via Epigenetic Mechanisms, Chae Young Han
Cellular Adaptation Of Macrophages To Anthrax Lethal Toxin-Induced Pyroptosis Via Epigenetic Mechanisms, Chae Young Han
Electronic Thesis and Dissertation Repository
Cellular adaptation to microbial stresses has been demonstrated in several cell types. Macrophages (MФ) are sentinel immune cells fending off invading microbes. Anthrax lethal toxin (LeTx) is a key virulence factor released by Bacillus anthracis that causes rapid cell death, pyroptosis. A small number of RAW246.7 macrophages (~4%) exposed to a non-lethal dose of LeTx become resistant to LeTx-induced pyroptosis for ~ 4 weeks, termed “toxin-induced resistance (TIR)”. Here, I showed that high levels of DNA methyl transferase1 (DNMT1) expression were maintained although global genomic methylation levels were not high in TIR. TIR cells treated with the DNMT inhibitor 5-azacitidine …