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Comparative study of the physiological roles of three peroxidases (NADH peroxidase, Alkyl hydroperoxide reductase and Thiol peroxidase) in oxidative stress response, survival inside macrophages and virulence of Enterococcus faecalis.
- Source :
-
Molecular microbiology [Mol Microbiol] 2007 Dec; Vol. 66 (5), pp. 1148-63. Date of Electronic Publication: 2007 Oct 28. - Publication Year :
- 2007
-
Abstract
- The opportunistic pathogen Enterococcus faecalis is well equipped with peroxidatic activities. It harbours three loci encoding a NADH peroxidase, an alkyl hydroperoxide reductase and a protein (EF2932) belonging to the AhpC/TSA family. We present results demonstrating that ef2932 does encode a thiol peroxidase (Tpx) and show that it is part of the regulon of the hydrogen peroxide regulator HypR. Characterization of unmarked deletion mutants showed that all three peroxidases are important for the defence against externally provided H(2)O(2). Exposure to internal generated H(2)O(2) by aerobic growth on glycerol, lactose, galactose or ribose showed that Npr was absolutely required for aerobic growth on glycerol and optimal growth on the other substrates. Growth on glycerol was also dependent on Ahp. Addition of catalase restored growth of the mutants, and therefore, extracellular H(2)O(2) concentrations have been determined. This showed that the time point of growth arrest of the Deltanpr mutant correlated with the highest H(2)O(2) concentration measured. Analysis of the survival of the different strains inside peritoneal macrophages revealed that Tpx was the most important antioxidant activity for protecting the cells against the hostile phagocyte environment. Finally, the Deltatpx and the triple mutant showed attenuated virulence in a mouse peritonitis model.
- Subjects :
- Aerobiosis
Animals
Anti-Bacterial Agents pharmacology
Cells, Cultured
Colony Count, Microbial
Enterococcus faecalis drug effects
Enterococcus faecalis genetics
Gene Deletion
Hydrogen Peroxide pharmacology
Macrophages, Peritoneal microbiology
Mice
Microbial Viability
Oxidants pharmacology
Peritonitis microbiology
Peroxidases genetics
Peroxiredoxins genetics
Regulon genetics
Regulon physiology
Survival Analysis
Virulence
Enterococcus faecalis enzymology
Enterococcus faecalis physiology
Oxidative Stress
Peroxidases physiology
Peroxiredoxins physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0950-382X
- Volume :
- 66
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Molecular microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 17971082
- Full Text :
- https://doi.org/10.1111/j.1365-2958.2007.05987.x