Superoxide dismutase protects against aerobic heat shock in Escherichia coli.
Exposure of a superoxide dismutase-null (sodA sodB) strain of Escherichia coli to aerobic heat stress (45 to 48 degrees C) caused a profound loss of viability, whereas the same heat stress applied anaerobically had a negligible effect. A superoxide dismutase-competent parental strain was resistant to the lethal effect of the aerobic heating. It follows that aerobic heating imposes an oxidative burden of which O2- must be a major component. This effect is not seen at 53 degrees C, presumably because, at this higher temperature, direct thermolability of vital cell components overrides the effect of superoxide radicals.
Benov
L
L
Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.
Fridovich
I
I
D000332:Aerobiosis; D004926:Escherichia coli / Q000201:enzymology*; D006358:Hot Temperature; D013482:Superoxide Dismutase / Q000502:physiology*
D013482:Superoxide Dismutase