Effects Of Heavy Metals Cu～(2+) And Cd～(2+) Stress On Antioxidant Enzyme System Of Several Fly Species

The accumulation pattern of Cu2+ and Cd2+ and their effects on the antioxidant enzymes in Boettcherisca peregrina, changes of the SOD's isozyme after Cu2+ and Cd2+ exposure and SOD gene cloning were studied so as to define effects of heavy metals Cu2+ and Cd2+ stress on the antioxidant enzyme system of flies. The main results are summarized as follows:1. Accumulation of Cu2+ and Cd2+ and their effects on the antioxidant enzymes in Boettcherisca peregrina exposed to Cu2+ and Cd2+In Boettcherisca peregrina, changes in the activities of three species of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) were measured together with patterns of Cu2+ or Cd2+ accumulation as the newly hatched fly larvae were exposed to the diet containing Cu2+ or Cd2+. The results showed that the content of Cu2+ or Cd2+ in the fly increased markedly during larval stage depending on the time after exposure to Cu2+ or Cd2+, and decreased until pupation. Cu2+ (or Cd2+) exposure resulted in that the activities of SOD and CAT in the flies were significantly inhibited with an increase of Cu2+ or Cd2+ exposure concentration. In contrast, the activity of POD in the flies was inhibited as exposed to Cu2+ or Cd2+ at higher concentration, and elevated as exposed to Cu2+ or Cd2+ at lower concentration.2. Comparison of the isozyme profiles of superoxide dismutase among several fly speciesThe isozyme of superoxide dismutase was analysed using polyacrylamide gel...