Environmental regulation of Pseudomonas aeruginosa PAO1 Las and Rhl quorum-sensing systems.
The lasI-lasR and the rhlI-rhlR quorum-sensing systems in Pseudomonas aeruginosa regulate the expression of numerous cellular and secreted virulence factor genes and play important roles in the development of biofilms. The las and rhl systems themselves are known to be directly or indirectly regulated by a number of transcriptional regulators, and consequently, their expression is sensitive to environmental conditions. In this report, the activities of these two quorum-sensing systems have been examined systematically under 46 growth conditions, and the regulation by environmental conditions has been investigated. The relative timing and strength of expression of these two systems varied significantly under different conditions, which contrasts with the notion of a preset hierarchy with these two systems in P. aeruginosa. Depending on the growth conditions, the correlation between each synthase and its cognate transcriptional regulator also varied, suggesting that the transcription of these genes independently allows for further fine tuning of each system. Finally, we observe that the activities of both the lasI-lasR and the rhlI-rhlR quorum-sensing systems were dramatically enhanced in the presence of extracts of sputum samples from cystic fibrosis patients.
Duan
Kangmin
K
Faculty of Medicine, Department of Microbiology and Infectious Diseases, Biochemistry and Molecular Biology, University of Calgary, 3330 Hospital Drive NW, Calgary, Canada.
Surette
Michael G
MG
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D016000:Cluster Analysis; D015169:Colony Count, Microbial; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D006801:Humans; D007501:Iron / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D053038:Quorum Sensing / Q000235:genetics*; D012965:Sodium Chloride / Q000494:pharmacology; D013183:Sputum / Q000737:chemistry; D013997:Time Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C081237:LasI protein, Pseudomonas aeruginosa; C080365:LasR protein, Pseudomonas aeruginosa; C086515:RhlR protein, Pseudomonas aeruginosa; D015534:Trans-Activators; C088386:homoserine lactone; D012965:Sodium Chloride; D007501:Iron; D015107:4-Butyrolactone