Role of Pseudomonas aeruginosa PA4157in Quorum Sensing and Iron Transport Regulation

Pseudomonas aeruginosa, a Gram-negative opportunistic pathogen, is a pnmary contributing factor responsible for the morbidity and mortality in patients with cystic fibrosis. One of the trademarks of P. aeruginosa is its ability to resist antibiotics. P. aeruginosa does so in part through the LysR-type transcription factor, AmpR. To identify additional members of the AmpR regulon, a new algorithm called iterative enhancement of motifs was used to identify putative AmpR binding sites upstream of open reading frames in the P. aeruginosa genome. The surprising primary hit of this analysis was the promoter of an uncharacterized open reading frame, P A 415 7. P A 415 7 is located upstream ofthefep operon, which is known to be involved in iron acquisition. PA4157 shares high homology to the IclR family of transcriptional regulators which are known to regulate quorum sensing (QS), an elaborate cell-cell communication signaling system that uses quoromones. We postulated two hypotheses: 1) AmpR regulation of QS genes is mediated by PA4157, and 2) PA4157 may be involved in iron acquisition. To address the role of P A 415 7 we generated an in-frame chromosomal deletion of P A 415 7 in P. aeruginosa PA01 (PA0 PA4157). We compared PA0 PA4157 with its parent strain P A0 1 for its ability to produce quoromones using Chromobacterium violaceum as an indicator strain and LasA proteases using Staphylococcus aureus. We also tested its role in virulence using a Caenorhabditis elegans killing assay. Growth in iron-deficient media was also examined to determine if P A4157 has a potential role in iron uptake regulation. Our preliminary results suggest that P A 415 7 is not involved in quorum sensing regulation but does seem to exert a negative regulatory effect on iron uptake in P. aeruginosa P A0 1.

Alienated Selfhood and Heroism: A Poststructuralist Reading of John le Carré’s Spy Fiction Novels

John le Carré’s novels “The Spy Who Came in From the Cold” (1963), “Tinker, Tailor, Soldier, Spy” (1974), and “The Tailor of Panama” (1997), focus on how the main characters reflect the somber reality of working in the British intelligence service. Through a broad post-structuralist analysis, I will identify the dichotomies - good/evil in “The Spy Who Came in From the Cold,” past/future in “Tinker, Tailor, Soldier, Spy,” and institution/individual in “The Tailor of Panama” - that frame the role of the protagonists. Each character is defined by his ambiguity and swinging moral compass, transforming him into a hybrid creation of morality and adaptability during transitional time periods in history, mainly during the Cold War. Le Carré’s novels reject the notion of spies standing above a group being celebrated. Instead, he portrays spies as characters who trade off individualism and social belonging for a false sense of heroism, loneliness, and even death.