Effects of intracellular Mn on the radiation resistance of the halophilic archaeon Halobacterium salinarum.
Extremophiles
; 17(3): 485-97, 2013 May.
Article
em En
| MEDLINE
| ID: mdl-23532412
ABSTRACT
Ionizing radiation (IR) is of particular interest in biology because its exposure results in severe oxidative stress to the cell's macromolecules. Our recent work with extremophiles supports the idea that IR resistance is most likely achieved by a metabolic route, effected by manganese (Mn) antioxidants. Biochemical analysis of "super-IR resistant" mutants of H. salinarum, evolved over multiple cycles of exposure to high doses of IR, confirmed the key role for Mn antioxidants in the IR resistance of this organism. Analysis of the proteome of H. salinarum "super-IR resistant" mutants revealed increased expression for proteins involved in energy metabolism, replenishing the cell with reducing equivalents depleted by the oxidative stress inflicted by IR. Maintenance of redox homeostasis was also activated by the over-expression of coenzyme biosynthesis pathways involved in redox reactions. We propose that in H. salinarum, increased tolerance to IR is a combination of metabolic regulatory adjustments and the accumulation of Mn-antioxidant complexes.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tolerância a Radiação
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Halobacterium salinarum
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Raios gama
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Manganês
Idioma:
En
Revista:
Extremophiles
Ano de publicação:
2013
Tipo de documento:
Article