OXIDATIVE STRESS AND ANTIOXIDANTS IN STRESS AND RECOVERY OF COLD-HARDY INSECTS

Antioxidants, pro-oxidants, and oxidative stress and damage were studi ed in larvae of cold-hardy goldenrod gall insects during freezing (-14 degrees C, 24 h), anoxia (under N-2 gas, 24 h), and upon recovery fro m these stresses. Although oxidized glutathione levels increased durin g freezing, no oxidative damage was seen upon recovery from freezing a nd anoxia in freezing tolerant Eurosta solidaginis. Antioxidant enzyme activities were unchanged except for catalase activity which increase d gradually during freezing to peak at 147% of control values after 30 min of recovery at 3.5 degrees C. Xanthine oxidase activity was undet ected in E. solidaginis. Anoxia and recovery in freeze avoiding Epible ma scudderiana also failed to result in oxidative damage, although a s light increase in the pro-oxidant xanthine oxidase (from 12.5 to 18% o f total xanthine dehydrogenase + xanthine oxidase) was observed, No ch anges in antioxidant enzyme activities were observed in this species e ither during anoxia or upon aerobic recovery, The ability of these lar vae to limit oxidative damage arising during oxygen reperfusion during freezing-or anoxia-exposures is suggested to play an important role i n their capacity to survive these stresses. (C) 1998 Elsevier Science Ltd. All rights reserved.