title: Salmonella detoxifying enzymes are sufficient to cope with the host oxidative burst.
abstract: The oxidative burst produced by the NADPH oxidase (Phox) is an essential weapon used by host cells to eradicate engulfed pathogens. In Salmonella typhimurium, oxidative stress resistance has been previously proposed to be mediated by the pathogenicity island 2 type III secretion system (T3SS-2), periplasmic superoxide dismutases and cytoplasmic catalases/peroxidases. Here, we fused an OxyR-dependent promoter to the gfp to build the ahpC-gfp transcriptional fusion. This reporter was used to monitor hydrogen peroxide levels as sensed by Salmonella during the course of an infection. We showed that the expression of this fusion was under the exclusive control of reactive oxygen species produced by the host. The ahpC-gfp expression was noticeably modified in the absence of bacterial periplasmic superoxide dismutases or cytoplasmic catalases/peroxidases. Surprisingly, inactivation of the T3SS-2 had no effect on the ahpC-gfp expression. All together, these results led to a model in which Salmonella resistance relies on its arsenal of detoxifying enzymes to cope with Phox-mediated oxidative stress.
authors.affiliation: Laboratoire de Chimie Bactérienne - Institut de Microbiologie de la Méditerranée - IFR 88, UPR 9043 du CNRS, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 20, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Aussel
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhao
authors.forename: Magali
authors.initials: M
authors.lastname: Hébrard
authors.forename: Aude-Agnès
authors.initials: AA
authors.lastname: Guilhon
authors.forename: Julie P M
authors.initials: JP
authors.lastname: Viala
authors.forename: Sandrine
authors.initials: S
authors.lastname: Henri
authors.forename: Lionel
authors.initials: L
authors.lastname: Chasson
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Gorvel
authors.forename: Frédéric
authors.initials: F
authors.lastname: Barras
authors.forename: Stéphane
authors.initials: S
authors.lastname: Méresse
mesh_terms: D000818:Animals; D019677:Artificial Gene Fusion; D002478:Cells, Cultured; D004195:Disease Models, Animal; D020869:Gene Expression Profiling; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism*; D008658:Inactivation, Metabolic; D008264:Macrophages / Q000382:microbiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D050296:Microbial Viability / Q000187:drug effects; D010588:Phagosomes / Q000378:metabolism / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D016897:Respiratory Burst; D012481:Salmonella Infections, Animal / Q000276:immunology / Q000382:microbiology; D012486:Salmonella typhimurium / Q000187:drug effects* / Q000502:physiology; D013154:Spleen / Q000382:microbiology; D013481:Superoxides / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D013481:Superoxides; D049452:Green Fluorescent Proteins; D006861:Hydrogen Peroxide