The impairment of superoxide dismutase coordinates the derepression of the PerR regulon in the response of Staphylococcus aureus to HOCl stress.
The response of Staphylococcus aureus to hypochlorous acid (HOCl) exposure was investigated. HOCl challenges were performed on cultures interrupted in the exponential phase. Pretreatment with HOCl conferred resistance to hydrogen peroxide in a PerR-dependent manner. Derepression of the PerR regulon was observed at low HOCl concentration (survival >50 %), using several fusions of different stress promoters to lacZ reporter genes. At least four members of the PerR regulon (katA, mrgA, bcp and trxA) encoding proteins with antioxidant properties were strongly induced following exposure to various HOCl concentrations. A striking result was the link between the derepression of the PerR regulon and the decreased superoxide dismutase (SOD) activity following exposure to increased HOCl concentrations. The sodA mutant was more resistant than the wild-type and also had a higher level of 3-phosphoglycerate dehydrogenase (a measure of PerR regulon activity) without exposure to HOCl. Together, these results imply that derepression of PerR by HOCl is dependent on the level of SOD and protects exponentially arrested cells against HOCl stress.
Maalej
Sami
S
Laboratoire de chimie bactérienne IBSM, CNRS UPR 9043, 31, chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.|Laboratoire de Microbiologie, Faculté des Sciences de Sfax, 3018 Sfax, Tunisia.
Dammak
Ines
I
Laboratoire de Microbiologie, Faculté des Sciences de Sfax, 3018 Sfax, Tunisia.
Dukan
Sam
S
Laboratoire de chimie bactérienne IBSM, CNRS UPR 9043, 31, chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D024881:Drug Resistance, Bacterial; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006997:Hypochlorous Acid / Q000494:pharmacology*; D018085:Regulon; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
D001426:Bacterial Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; C122138:peroxide repressor proteins; D006997:Hypochlorous Acid; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase