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The Pseudomonas aeruginosa quinolone signal molecule overcomes the cell density-dependency of the quorum sensing hierarchy, regulates rhl-dependent genes at the onset of stationary phase and can be produced in the absence of LasR.

Diggle, Stephen P. and Winzer, Klaus and Chhabra, Siri Ram and Worrall, Kathryn E. and Cámara, Miguel and Williams, Paul (2003) The Pseudomonas aeruginosa quinolone signal molecule overcomes the cell density-dependency of the quorum sensing hierarchy, regulates rhl-dependent genes at the onset of stationary phase and can be produced in the absence of LasR. Molecular Microbiology, 50 (1). pp. 29-43. ISSN 0950-382X

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Abstract

In Pseudomonas aeruginosa, diverse exoproduct virulence determinants are regulated via N-acylhomoserine lactone-dependent quorum sensing. Here we show that 2-heptyl-3-hydroxy-4(1H)-quinolone (PQS) is also an integral component of the quorum sensing circuitry and is required for the production of rhl-dependent exoproducts at the onset of stationary phase. Analysis of spent P. aeruginosa culture supernatants revealed that PQS is produced at the end of exponential phase in the parent strain and in the late stationary phase of a lasR mutant. Mutants defective in both PQS production (pqsR-) and response (pqsE-) produced substantially reduced levels of exoproducts but retained wild-type N-butanoyl homoserine lactone (C4-HSL) levels. In the wild type, provision of exogenous PQS at the time of inoculation significantly increased PA-IL lectin, pyocyanin and elastase production during early stationary phase and promoted biofilm formation. Exogenous PQS but not PQS derivatives lacking the 3-hydroxy group overcame the cell density but not growth phase-dependent production of exoproducts. PQS also overcame the transcriptional and post-transcriptional repression of lecA (which codes for the PA-IL lectin) mediated via the negative regulators MvaT and RsmA respectively. Increased expression of lecA in the presence of exogenous PQS can be explained partially by increases in RhlR, RpoS and C4-HSL levels. A refined model for quorum sensing in P. aeruginosa is presented.

Item Type: Article
Journal or Publication Title: Molecular Microbiology
Subjects: Q Science > QH Natural history > QH301 Biology
Departments: Faculty of Health and Medicine > Biomedical & Life Sciences
ID Code: 9546
Deposited By: Dr Klaus Winzer
Deposited On: 13 Jun 2008 14:15
Refereed?: Yes
Published?: Published
Last Modified: 09 Apr 2014 22:17
Identification Number:
URI: http://eprints.lancs.ac.uk/id/eprint/9546

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