Superoxide dismutase, thermal respiratory acclimation, and growth in an earthworm, Eisenia foetida.

The superoxide dismutase activity units/mg protein were determined for earthworms (Eisenia foetida) acclimated at 15°, 22.5° and 30°C. Worms acclimated at 15° gave a value of SOD units significantly lower than those acclimated at 30°. Those at 22.5° gave an intermediate value. SOD activity units of the anterior, mid and posterior regions showed no indication of the classical U-shaped axial gradient of respiration. SOD levels increased as O₂uptake increased, though to a lesser extent, indicating that SOD levels are somehow tied to metabolic rate even if not in a one to one relationship. The increased ratio of SOD/specific metabolic rate of 15° compared to 30° acclimates implies that at 15° worms have more protection against the superoxide radical and thus would be expected to survive longer.