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A hierarchical quorum‐sensing system in Yersinia pseudotuberculosis is involved in the regulation of motility and clumping
Author(s) -
Atkinson Steve,
Throup John P.,
Stewart Gordon S.A.B.,
Williams Paul
Publication year - 1999
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1999.01578.x
Subject(s) - yersinia pseudotuberculosis , biology , quorum sensing , homoserine , mutant , motility , escherichia coli , microbiology and biotechnology , genetics , gene , virulence
In cell‐free Yersinia pseudotuberculosis culture supernatants, we have chemically characterized three N ‐acyl homoserine lactone (AHL) molecules, N ‐octanoyl homoserine lactone (C8‐HSL), N ‐(3‐oxohexanoyl)homoserine lactone (3‐oxo‐C6‐HSL) and N ‐hexanoyl homoserine lactone (C6‐HSL). We have identified, cloned and sequenced two pairs of LuxR/I homologues termed YpsR/I and YtbR/I. In Escherichia coli at 37°C, YpsI and YtbI both synthesize C6‐HSL, although YpsI is responsible for 3‐oxo‐C6‐HSL and YtbI for C8‐HSL synthesis respectively. However, in a Y. pseudotuberculosis ypsI ‐negative background, YtbI appears capable of adjusting the AHL profile from all three AHLs at 37°C and 22°C to the absence of 3‐oxo‐C6‐HSL at 28°C. Insertion deletion mutagenesis of ypsR leads to the loss of C8‐HSL at 22°C, which suggests that at this temperature the YpsR protein is involved in the hierarchical regulation of the ytbR/I locus. When compared with the parent strain, the ypsR and ypsI mutants exhibit a number of phenotypes, including clumping ( ypsR mutant), overexpression of a major flagellin subunit ( ypsR mutant) and increased motility (both ypsR and ypsI mutants). The clumping and motility phenotypes are both temperature dependent. These data are consistent with a hierarchical quorum‐sensing cascade in Y. pseudotuberculosis that is involved in the regulation of clumping and motility.