Abstract

EXCEED THE SPACE PROVIDED. The long term goal of this research is to determine the role of autoinduction (quorum sensing (QS)) in the pathogenesis of Pseudomonas aeruginosa. In P. aeruginosa, two QS systems, las and rhl, plus a third signal (Pseudomonas quinolone signal) (PQS) control the expression of many virulence factors and group behavior such as biofilm development, swarming and twitching. Recent studies, including transcriptome analysis, indicates that the P. aeruginosa QS regulon is much more complex than previously thought. Our hypothesis is that the QS regulon is composed of a complex regulatory cascade with the principal regulator LasR-3O- C12 HSL regulating expression of the genes qscR, vqsR and rhlR. These later genes are also transcriptional regulators (TRs) and we refer to them and lasR as the master regulators. As a group these four master TRs control expression of 33 known or putative TRs and over 550 other genes.
The specific aims of the current R37 extension propos'al are: 1. Determine which genes are regulated by RhlR-C4 HSL and VqsR. (Others are working on qscR). 2. Determine which of the TRs are involved in P. aeruginosa virulence and biofilm development. 3. Further characterize TR genes identified in aim 2. Use unmarked, null mutants in traditional biofilm models as well as a novel biofilm model employing airway surface liquid (ASL) and in two models of P. aeruginosa infection (nematodes and leaf lettuce). Do transcriptome analysis on selected TR null mutants and their complemented versions. 4. Initiate studies on the role of QS in mixed cultures of P. aeruginosa and Staphylococcus aureus or Burkholderia cenocepacia. When wild type strains of these organisms are mixed together in planktonic cultures, the P aeruginosa takes over. We will determine if that requires QS regulated genes and if this dominance is also seen in biofilms. The results of these studies will further our understanding of regulation of virulence in P. aeruginosa. They will provide new insights into quorum sensing systems in general and determine the feasibility of a new approach to therapy for gram negative infections.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
4R37AI033713-14
Application #
6935475
Study Section
Special Emphasis Panel (NSS)
Program Officer
Taylor, Christopher E,
Project Start
1993-01-01
Project End
2010-12-31
Budget Start
2006-01-15
Budget End
2006-12-31
Support Year
14
Fiscal Year
2006
Total Cost
$390,000
Indirect Cost

  Institution

Name
University of Rochester
Department
Microbiology/Immun/Virology
Type
Schools of Dentistry
DUNS #
041294109
City
Rochester
State
NY
Country
United States
Zip Code
14627

  Publications

Filiatrault, Melanie J; Tombline, Gregory; Wagner, Victoria E et al. (2013) Pseudomonas aeruginosa PA1006, which plays a role in molybdenum homeostasis, is required for nitrate utilization, biofilm formation, and virulence. PLoS One 8:e55594
Tombline, Gregory; Schwingel, Johanna M; Lapek Jr, John D et al. (2013) Pseudomonas aeruginosa PA1006 is a persulfide-modified protein that is critical for molybdenum homeostasis. PLoS One 8:e55593
Van Alst, Nadine E; Wellington, Melanie; Clark, Virginia L et al. (2009) Nitrite reductase NirS is required for type III secretion system expression and virulence in the human monocyte cell line THP-1 by Pseudomonas aeruginosa. Infect Immun 77:4446-54
Van Alst, Nadine E; Sherrill, Lani A; Iglewski, Barbara H et al. (2009) Compensatory periplasmic nitrate reductase activity supports anaerobic growth of Pseudomonas aeruginosa PAO1 in the absence of membrane nitrate reductase. Can J Microbiol 55:1133-44
Li, Luen-Luen; Malone, Jane E; Iglewski, Barbara H (2007) Regulation of the Pseudomonas aeruginosa quorum-sensing regulator VqsR. J Bacteriol 189:4367-74
Van Alst, Nadine E; Picardo, Kristin F; Iglewski, Barbara H et al. (2007) Nitrate sensing and metabolism modulate motility, biofilm formation, and virulence in Pseudomonas aeruginosa. Infect Immun 75:3780-90
Filiatrault, Melanie J; Picardo, Kristin F; Ngai, Helen et al. (2006) Identification of Pseudomonas aeruginosa genes involved in virulence and anaerobic growth. Infect Immun 74:4237-45
Filiatrault, M J; Wagner, V E; Bushnell, D et al. (2005) Effect of anaerobiosis and nitrate on gene expression in Pseudomonas aeruginosa. Infect Immun 73:3764-72
Gillis, Richard J; Iglewski, Barbara H (2004) Azithromycin retards Pseudomonas aeruginosa biofilm formation. J Clin Microbiol 42:5842-5
Lamb, Janet R; Patel, Hetal; Montminy, Timothy et al. (2003) Functional domains of the RhlR transcriptional regulator of Pseudomonas aeruginosa. J Bacteriol 185:7129-39

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