Oxygen dependency of life-span in the nematode.

1. The mean and maximum life-spans of both wild type Caenorhabditis elegans and the mev-1(kn1) mutant, whose cytoplasmic superoxide dismutase activity level is about half of the wild type, were increased and decreased under low and high concentrations of oxygen, respectively. 2. The Gompertz component, a parameter of ageing rate, of the wild type was smaller under 1% oxygen than under 2% or more oxygen. Further, the Gompertz component of the mutant increased with an increase in oxygen concentration. 3. The oxygen-dependent modulation of life-span and ageing rate seems to be enhanced by a genetic defect of the mutant in antioxidant defence.