title: Implication of (Mn)superoxide dismutase of Enterococcus faecalis in oxidative stress responses and survival inside macrophages.
abstract: The gene encoding the manganese-containing superoxide dismutase (MnSOD) of Enterococcus faecalis was characterized. It is transcribed monocistronically from an upstream promoter identified by rapid amplification of cDNA ends (RACE)-PCR. A sodA mutant was constructed and characterized. Growth of the mutant strain was not significantly different from that of its wild-type counterpart in standing and aerated cultures. However, the mutant was more sensitive towards menadione and hydroperoxide stresses. The response to H(2)O(2) stress was analysed in more detail, and the mode of killing of this oxidant was different under anaerobic and aerobic conditions. Cultures grown and challenged under anaerobic conditions were highly sensitive to treatment with 35 mM H(2)O(2). They were largely protected by the iron chelator deferoxamine, which suggested that killing was mainly due to an enhanced Fenton reaction. In contrast, neither strain was protected by the iron chelators deferoxamine and diethylenetriaminepentaacteic acid when grown and challenged under aerobic conditions, which suggested that inactivation of the cells by H(2)O(2) was due to another killing mode. The sodA mutant was more sensitive under these conditions, showing that MnSOD is also important for protecting the cells from damage under aerobic conditions. Finally, the MnSOD of Ent. faecalis may be considered to be a virulence factor, since survival of the corresponding mutant strain was highly affected inside mouse peritoneal macrophages.
authors.affiliation: Laboratoire de Microbiologie de l'Université de Caen, EA956 USC INRA 2017, 14032 CAEN Cedex, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Verneuil
authors.affiliation: Laboratoire de Microbiologie de l'Université de Caen, EA956 USC INRA 2017, 14032 CAEN Cedex, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Mazé
authors.affiliation: Institute of Microbiology, Catholic University of Sacred Heart, L. go F. Vito 1, 00168, Rome, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Sanguinetti
authors.affiliation: Laboratoire de Microbiologie de l'Université de Caen, EA956 USC INRA 2017, 14032 CAEN Cedex, France.
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Laplace
authors.affiliation: Laboratoire de Microbiologie de l'Université de Caen, EA956 USC INRA 2017, 14032 CAEN Cedex, France.
authors.forename: Abdellah
authors.initials: A
authors.lastname: Benachour
authors.affiliation: Laboratoire de Microbiologie de l'Université de Caen, EA956 USC INRA 2017, 14032 CAEN Cedex, France.
authors.forename: Yanick
authors.initials: Y
authors.lastname: Auffray
authors.affiliation: Laboratoire de Microbiologie de l'Université de Caen, EA956 USC INRA 2017, 14032 CAEN Cedex, France.
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Giard
authors.affiliation: Laboratoire de Microbiologie de l'Université de Caen, EA956 USC INRA 2017, 14032 CAEN Cedex, France.
authors.forename: Axel
authors.initials: A
authors.lastname: Hartke
mesh_terms: D000818:Animals; D013293:Enterococcus faecalis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D005816:Genetic Complementation Test; D007700:Kinetics; D017737:Macrophages, Peritoneal / Q000201:enzymology* / Q000382:microbiology*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D018384:Oxidative Stress; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism*
chemical_list: D013482:Superoxide Dismutase