首页|期刊导航|中国农业科学（英文版）|Comparative Study of Malathion Toxicity and General Esterases in Larvae and Adults from a Field Population of Oxya chinensis (Thunberg)(Orthoptera:Acridoidea)
中国农业科学（英文版）2004，Vol.3Issue(11)：812-821,10.
Comparative Study of Malathion Toxicity and General Esterases in Larvae and Adults from a Field Population of Oxya chinensis (Thunberg)(Orthoptera:Acridoidea)
Comparative Study of Malathion Toxicity and General Esterases in Larvae and Adults from a Field Population of Oxya chinensis (Thunberg)(Orthoptera:Acridoidea)
摘要
Abstract
The susceptibility of Oxya chinensis to malathion was compared in larvae and adults from a field population, collected from Jinyuan outskirt, Shanxi Province. The results showed that Oxya chinensis was more susceptible to malathion in the adult stage than in the larval stage. The LD50 values for malathion susceptibility of Oxya chinensis were 4.94 and 2.44 mg g-1 body weight in the larvae and adults respectively. The results indicated that the larvae were 2.02-fold less susceptible to malathion than the adults. The general esterases and the kinetics were characterized and compared between the two life stages and between females and males. Larval preparations of Oxya chinensis were more active than adult preparations in females and males. The larvae showed 1.18-, 1.49-, and 1.17-fold higher specific activities than the adults in females with α -NA, α -NB and β -NA respectively. In males, the ratios were 1.34-, 1.70-, and 1.06-fold. Female preparations were more active than those of males in the adults. The reverse results were observed in the larvae where male preparations were more active than female preparations. Kinetic studies showed that Km values of general esterases hydrolyzing α -NA, α -NB, and β -NA in the adult stage were 1.36-, 1.32- and 1.39-fold respectively, higher than those in the larval stage in females. In males, the ratios were 1.24-, 2.14-, and 1.20-fold. The esterase from male insects had a higher affinity (lower Km value) to the substrate than those from females. The results also showed that the Vmax values of general esterase hydrolyzing α -NA, α -NB, and β -NA in the two stages were similar. From the results of bioassays and biochemical analyses, it has been inferred that a higher level of resistance to malathion in larvae than in adults would appear to result from differences in the expression of resistance mechanisms in these two life stages. Enhanced esterase activities appeared to play a major role in resistance to malathion in both larvae and adults. From the analysis of inhibition in vitro, the esterases in the two life stages were B-type,and carboxylesterases were predominant enzymes in the composition of the esterases in the two stages.关键词
Oxya chinensis/Larvae and adults/Malathion toxicity/General esterase/Enzyme kinetics/Enzyme inhibitionKey words
Oxya chinensis/Larvae and adults/Malathion toxicity/General esterase/Enzyme kinetics/Enzyme inhibition引用本文复制引用
WU Hai-hua,YANG Mei-ling,GUO Ya-ping,MA En-bo..Comparative Study of Malathion Toxicity and General Esterases in Larvae and Adults from a Field Population of Oxya chinensis (Thunberg)(Orthoptera:Acridoidea)[J].中国农业科学（英文版）,2004,3(11):812-821,10.基金项目
This work was supported by the National Natural Science Foundation of China (30170612), and the Science and Technology Commission of Shanxi Province (041005) to MA Enbo. （30170612）
