Journal ArticleDOI
Pseudomonas aeruginosa with lasI quorum-sensing deficiency during corneal infection.
Hua Zhu,Rani Bandara,Tim C.R. Conibear,Sophy J Thuruthyil,Scott A. Rice,Staffan Kjelleberg,Michael Givskov,Mark D. P. Willcox +7 more
TLDR
Results indicate that quorum-sensing deficiency may occur naturally in clinical isolates, and the possession of lasI and hence a functional Las quorum -sensing system may be important in development of corneal infection.Abstract:
Purpose To understand the importance of Pseudomonas aeruginosa quorum-sensing systems in the development of corneal infection, the genotypic characteristics and pathogenesis of seven ocular isolates with low-protease and acyl homoserine lactone (AHL) activity and quorum-sensing mutants of PAO1 deficient in lasI, lasR, or rhlR were investigated in the study. Methods The possession of the quorum-sensing genes lasI, lasR, rhlI, rhlR, and the quorum-sensing controlled genes lasB, aprA, and rhlAB in the clinical isolates were determined by polymerase chain reaction and Southern blot hybridization. Elastinolytic activity, controlled by the las system, was assayed using elastin Congo red and rhamnolipid production controlled by the rhl system was assessed using agar plates containing methylene blue/cetyltrimethyl ammonium bromide. Induction of keratitis was examined in a scarified inbred BALB/c mouse model. Results The clinical isolates Paer1 and -3 were lasI and lasR negative, and the isolates Paer2 and -4 were rhlR and rhlAB negative. The isolates Paer17, Paer26, 6294 and 6206 possessed all the genes examined. There was no rhamnolipid production in clinical isolates Paer2 and -4. The isolates Paer1 and -3 were virtually avirulent in the scarified mouse corneas. Using isogenic PAO1 mutants, strain lasI showed a markedly reduced virulence in the corneal infection model. The remainder of the clinical isolates and the lasR or rhlR mutant strains caused severe keratitis. Conclusions These results indicate that quorum-sensing deficiency may occur naturally in clinical isolates, and the possession of lasI and hence a functional Las quorum-sensing system may be important in development of corneal infection.read more
Citations
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Journal ArticleDOI
Acyl-Homoserine Lactone Quorum Sensing: From Evolution to Application
TL;DR: Quorum sensing is a widespread process in bacteria that employs autoinducing chemical signals to coordinate diverse, often cooperative activities such as bioluminescence, biofilm formation, and exoenzyme secretion and appreciating social dynamics is pertinent to understanding the efficacy of QS-inhibiting drugs and the evolution of resistance.
Journal ArticleDOI
Alternative Sigma Factors and Their Roles in Bacterial Virulence
TL;DR: This work presents several examples of alternative sigma factors that have been shown to contribute to virulence in at least one organism and describes how these proteins can contribute both directly and indirectly to bacterial virulence.
Journal ArticleDOI
Bacterial Quorum Sensing and Microbial Community Interactions.
TL;DR: A review of models and recent advances in understanding how microbes might interact with one another using quorum sensing discusses some of these models and the potential to guide studies of microbial sociality in natural settings and the design of new medicines and therapies to treat bacterial infections.
Journal ArticleDOI
Growth phenotypes of Pseudomonas aeruginosa lasR mutants adapted to the airways of cystic fibrosis patients.
David A. D'Argenio,Manhong Wu,Lucas R. Hoffman,Hemantha D. Kulasekara,Eric Déziel,Eric E. Smith,Hai Nguyen,Robert K. Ernst,Theodore J. Larson Freeman,David H. Spencer,Mitchell J. Brittnacher,Hillary S. Hayden,Sara E. Selgrade,Mikkel Klausen,David R. Goodlett,Jane L. Burns,Bonnie W. Ramsey,Samuel I. Miller +17 more
TL;DR: In this article, the authors identified Pseudomonas aeruginosa lasR mutants that emerged in the airway of a CF patient early during chronic infection, and during growth in the laboratory on a rich medium.
Journal ArticleDOI
Urinary tract infections caused by Pseudomonas aeruginosa: a minireview.
TL;DR: The aim of this review is to summarize some of the advances made in the field of P. aeruginosa induced UTIs and draws attention of the workers that more basic research at the level of pathogenesis is needed so that novel strategies can be designed.
References
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Book
Experiments in molecular genetics
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Journal ArticleDOI
Census and consensus in bacterial ecosystems: the LuxR-LuxI family of quorum-sensing transcriptional regulators.
TL;DR: Genetic analyses of particular bacterial genes, operons, or regulons that are expressed preferentially at high cell densities have revealed a high degree of functional conservation, while also uncovering features that are unique to each.
Journal ArticleDOI
Bacterial Quorum Sensing in Pathogenic Relationships
TL;DR: Examples of pathogenic relationships are given, focusing on organisms for which many of the facets of their quorum-sensing systems have been elucidated.
Journal ArticleDOI
Quinolone signaling in the cell-to-cell communication system of Pseudomonas aeruginosa
Everett C. Pesci,Jared B. J. Milbank,James P. Pearson,Susan L. McKnight,Andrew S. Kende,E. Peter Greenberg,Barbara H. Iglewski +6 more
TL;DR: The demonstration that 2-heptyl-3-hydroxy-4-quinolone can function as an intercellular signal sheds light on the role of secondary metabolites and shows that P. aeruginosa cell-to-cell signaling is not restricted to acyl-homoserine lactones.
Journal ArticleDOI
Roles of Pseudomonas aeruginosa las and rhl quorum-sensing systems in control of elastase and rhamnolipid biosynthesis genes.
TL;DR: The roles of the rhl and las quorum-sensing systems in virulence gene expression are characterized and RNA analysis of the wild-type strain revealed that rhlAB is organized as an operon.
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