The oxidative and nitrosative stress defence network of Wolinella succinogenes: cytochrome c nitrite reductase mediates the stress response to nitrite, nitric oxide, hydroxylamine and hydrogen peroxide.
Environ Microbiol
; 13(9): 2478-94, 2011 Sep.
Article
em En
| MEDLINE
| ID: mdl-21672122
ABSTRACT
Microorganisms employ diverse mechanisms to withstand physiological stress conditions exerted by reactive or toxic oxygen and nitrogen species such as hydrogen peroxide, organic hydroperoxides, superoxide anions, nitrite, hydroxylamine, nitric oxide or NO-generating compounds. This study identified components of the oxidative and nitrosative stress defence network of Wolinella succinogenes, an exceptional Epsilonproteobacterium that lacks both catalase and haemoglobins. Various gene deletion-insertion mutants were constructed, grown by either fumarate respiration or respiratory nitrate ammonification and subjected to disc diffusion, growth and viability assays under stress conditions. It was demonstrated that mainly two periplasmic multihaem c-type cytochromes, namely cytochrome c peroxidase and cytochrome c nitrite reductase (NrfA), mediated resistance to hydrogen peroxide. Two AhpC-type peroxiredoxin isoenzymes were shown to be involved in protection against different organic hydroperoxides. The phenotypes of two superoxide dismutase mutants lacking either SodB or SodB2 implied that both isoenzymes play important roles in oxygen and superoxide stress defence although they are predicted to reside in the cytoplasm and periplasm respectively. NrfA and a cytoplasmic flavodiiron protein (Fdp) were identified as key components of nitric oxide detoxification. In addition, NrfA (but not the hybrid cluster protein Hcp) was found to mediate resistance to hydroxylamine stress. The results indicate the presence of a robust oxidative and nitrosative stress defence network and identify NrfA as a multifunctional cytochrome c involved in both anaerobic respiration and stress protection.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Wolinella
/
Citocromos c1
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Hidroxilamina
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Citocromos a1
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Peróxido de Hidrogênio
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Nitrato Redutases
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Óxido Nítrico
/
Nitritos
Idioma:
En
Revista:
Environ Microbiol
Assunto da revista:
MICROBIOLOGIA
/
SAUDE AMBIENTAL
Ano de publicação:
2011
Tipo de documento:
Article
País de afiliação:
Alemanha