Effects of borax sublethal concentrations on the activity of antioxidant enzymes and lipid peroxidation changes in Microcerotermes diversus Silvestri (Isoptera: Termitidae)
عنوان دوره: دومین کنگره بین المللی حشره شناسی ایران
نویسندگان
چکیده
Microcerotermes diversus is an important pest of wooden and cellulosic products in diverse landscapes across Iran, including Khuzestan province. Borate toxicants affect insects by disrupting their physiology and metabolism. Boron is a key element for insect survival, but borate’s most important role is stimulating performance of enzymes. However, high boron concentrations lead to dysfunction of insect physiology. Borates are odorless, non-volatile, slow-acting, and non-repellent, and are used to control termites. In this study, we measured activities of antioxidant enzymes and lipid peroxidation as biomarkers to determine the level of added oxidative stress in M. diversus caused by exposure to sub-lethal borax concentrations. We used beech wood to trap workers. Then we measured the effect of termite exposure to five sublethal concentrations of borax, 0, 1.5, 2, 3 and 4%, on oxidative stress biomarkers such as Malondialdehyde (MDA) as a product of lipid peroxidation, and activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX). We exposed the termites to the 0, 1.5, 2, 3, and 4% (W/V) borax treatments, sprayed on cellulosic substrate surface, and then placed termites on filter paper surface. A completely random design with four replicates each of five treatments was used. Temperature and relative humidity were 28±2℃ and 85±5% in a dark incubator. The units of measurement of enzyme activity was U/mg of protein. Results showed that with increasing concentration of borax, the concentration of MDA significantly increased. The highest and lowest SOD activity compared with the control treatment occurred with the 2% and 3% borax treatments, respectively. The highest and lowest amount of CAT activity occurred in the 3% and 4%, and POX activity 4% and 3% borax treatments, respectively. Results showed that of termites’ sublethal concentrations of borax affects the stress biomarker Malondialdehyde, and POX, CAT, and SOD antioxidant enzyme levels. Therefore, borax can be used as a biomarker to determine the effect of insecticides in the termite body.
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