Premium
Regulation of alkaline metalloprotease promoter by N ‐acyl homoserine lactone quorum sensing in Pseudomonas fluorescens
Author(s) -
Liu M.,
Wang H.,
Griffiths M.W.
Publication year - 2007
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2007.03488.x
Subject(s) - pseudomonas fluorescens , quorum sensing , homoserine , biochemistry , microbiology and biotechnology , biology , bacteria , chemistry , gene , virulence , genetics
Aims: To examine the involvement of N ‐acyl homoserine lactone (AHL) quorum sensing in alkaline metalloprotease ( aprX ) promoter regulation in a Pseudomonas fluorescens milk isolate. Methods and Results: N ‐acyl homoserine lactone signals from P. fluorescens strain 395 were separated and detected by thin layer chromatography (TLC). Further analysis of the AHL signals using liquid chromatography–electrospray ionization‐mass spectrometry (LC‐ESI‐MS) indicated the presence of C4‐HSL and 3OC8‐HSL. The expression of aprX in P. fluorescens 395 was investigated, using a transcriptional fusion between the aprX promoter and a mutated gfp variant gene ( gfp [mut3]). The results demonstrated that the activity of the aprX promoter increased dramatically in the late exponential phase of growth, indicating growth phase‐dependent regulation. The activity was repressed in an AHL‐deficient environment, in which the signal molecules were hydrolysed by the enzyme AHL lactonase. Conclusions: N ‐acyl homoserine lactones produced by P. fluorescens 395 were identified to be C4‐HSL and 3OC8‐HSL. The protease gene in P. fluorescens is regulated by the AHL‐based quorum sensing system at a transcriptional level during the late exponential growth phase. Significance and Impact of the Study: This study contributes to our understanding of the genetic regulation and ecology of P. fluorescens in the economically important system of food spoilage.