Quorum sensing regulates dpsA and the oxidative stress response in Burkholderia pseudomallei
- 1 December 2006
- journal article
- Published by Microbiology Society in Microbiology
- Vol. 152 (12) , 3651-3659
Abstract
Burkholderia pseudomallei is the causative agent of melioidosis, a fatal human tropical disease. The non-specific DNA-binding protein DpsA plays a key role in protecting B. pseudomallei from oxidative stress mediated, for example, by organic hydroperoxides. The regulation of dpsA expression is poorly understood but one possibility is that it is regulated in a cell population density-dependent manner via N-acylhomoserine lactone (AHL)-dependent quorum sensing (QS) since a lux-box motif has been located within the dpsA promoter region. Using liquid chromatography and tandem mass spectrometry, it was first established that B. pseudomallei strain PP844 synthesizes AHLs. These were identified as N-octanoylhomoserine lactone (C8-HSL), N-(3-oxooctanoyl)homoserine lactone (3-oxo-C8-HSL), N-(3-hydroxyoctanoyl)-homoserine lactone (3-hydroxy-C8-HSL), N-decanoylhomoserine lactone (C10-HSL), N-(3-hydroxydecanoyl) homoserine lactone (3-hydroxy-C10-HSL) and N-(3-hydroxydodecanoyl)homoserine lactone (3-hydroxy-C12-HSL). Mutation of the genes encoding the LuxI homologue BpsI or the LuxR homologue BpsR resulted in the loss of C8-HSL and 3-oxo-C8-HSL synthesis, demonstrating that BpsI was responsible for directing the synthesis of these AHLs only and that bpsI expression and hence C8-HSL and 3-oxo-C8-HSL production depends on BpsR. In bpsI, bpsR and bpsIR mutants, dpsA expression was substantially down-regulated. Furthermore, dpsA expression in Escherichia coli required both BpsR and C8-HSL. bpsIR-deficient mutants exhibited hypersensitivity to the organic hydroperoxide tert-butyl hydroperoxide by displaying a reduction in cell viability which was restored by provision of exogenous C8-HSL (bpsI mutant only), by complementation with the bpsIR genes or by overexpression of dpsA. These data indicate that in B. pseudomallei, QS regulates the response to oxidative stress at least in part via the BpsR/C8-HSL-dependent regulation of DpsA.Keywords
This publication has 37 references indexed in Scilit:
- Melioidosis: Epidemiology, Pathophysiology, and ManagementClinical Microbiology Reviews, 2005
- Identification of Quorum-Sensing-Regulated Genes of Burkholderia cepaciaJournal of Bacteriology, 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 LasRMolecular Microbiology, 2003
- Synthetic Analogues of the Bacterial Signal (Quorum Sensing) Molecule N-(3-Oxododecanoyl)-l-homoserine Lactone as Immune ModulatorsJournal of Medicinal Chemistry, 2002
- Controlling infection by tuning in and turning down the volume of bacterial small-talkThe Lancet Infectious Diseases, 2002
- Advancing the Quorum in Pseudomonas aeruginosa : MvaT and the Regulation of N -Acylhomoserine Lactone Production and Virulence Gene ExpressionJournal of Bacteriology, 2002
- The pKNOCK Series of Broad-Host-Range Mobilizable Suicide Vectors for Gene Knockout and Targeted DNA Insertion into the Chromosome of Gram-Negative BacteriaBioTechniques, 1999
- tert.-Butyl hydroperoxide-mediated DNA base damage in cultured mammalian cellsMutation Research - Fundamental and Molecular Mechanisms of Mutagenesis, 1994
- A novel DNA-binding protein with regulatory and protective roles in starved Escherichia coli.Genes & Development, 1992
- Mini-Tn5 transposon derivatives for insertion mutagenesis, promoter probing, and chromosomal insertion of cloned DNA in gram-negative eubacteriaJournal of Bacteriology, 1990