Implication of (Mn)superoxide dismutase of Enterococcus faecalis in oxidative stress responses and survival inside macrophages

Nicolas Verneuil; Alain Mazé; Maurizio Sanguinetti; Jean-Marie Laplace; Abdellah Benachour; Yanick Auffray; Jean-Christophe Giard; Axel Hartke

Implication of (Mn)superoxide dismutase of Enterococcus faecalis in oxidative stress responses and survival inside macrophages

Nicolas Verneuil ¹ Alain Mazé ¹ Maurizio Sanguinetti ² Jean-Marie Laplace ¹ Abdellah Benachour ¹ Yanick Auffray ¹ Jean-Christophe Giard ¹ Axel Hartke ¹

1 LME - Laboratoire de Microbiologie de l’Environnement

2 Istituto di Microbiologia - Institute of Microbiology [Rome]

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 H2O2 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 H2O2. 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 H2O2 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.

Keywords : Reactive oxygen species SOD Superoxide dismutase tBOOH Cm Chloramphenicol DAPE Diaminopimelate epimerase Em Erythromycin MnSOD Manganese-containing superoxide dismutase RACE-PCR Rapid amplification of cDNA ends PCR ROS Tert-butylhydroperoxide

Type de document :

Article dans une revue

Domaine :

Sciences du Vivant [q-bio]

Sciences du Vivant [q-bio] / Biochimie, Biologie Moléculaire

Liste complète des métadonnées

https://hal-normandie-univ.archives-ouvertes.fr/hal-02181936
Contributeur : Axel Hartke <>
Soumis le : vendredi 12 juillet 2019 - 14:51:56
Dernière modification le : mercredi 18 septembre 2019 - 13:36:02

Implication of (Mn)superoxide dismutase of Enterococcus faecalis in oxidative stress responses and survival inside macrophages

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Implication of (Mn)superoxide dismutase of Enterococcus faecalis in oxidative stress responses and survival inside macrophages

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