Starvation and Cadmium Affect Glutathione and Detoxifying Enzymes in Larvae of Spodoptera Exigua from Control and Cadmium Strain

Abstract

Extended Abstract Related to industrial and urban pollution, high load of cadmium in soil has been commonly noticed. That may cause an increase of metal amounts in herbivore food, host plant, among the others, in the hyperaccumulators of cadmium. Various environmental factors such as short period of starvation and metal exposure may affect differently detoxification processes in insects. The one of the indicative of metal toxicity may be oxidative stress, and enhanced cost of antioxidant defence. Glutathione is the main thiol in living cells. It plays an important role in antioxidant defense. About 90% is present in reduced form. Excessive oxidation can result in the formation of more disulfide, oxidized glutathione [1]. In a study carried out on Spodoptera exigua , the activity of the detoxifying enzyme glutathione S-transferase was checked in larvae from the first and second generation of these insects treated with zinc and cadmium added to the medium. Increase in the activity of the GST enzyme in the fat body and Malpighi tubules caused by zinc and its reduction under the influence of cadmium have been observed [2]. The presence of cadmium in the diet of the last instar S. exigua larvae resulted in lower larval survival rate and longer larval stages duration. Cadmium also contributed to an increase of total antioxidant capacity in the larval hemolymph