棉蚜抗吡虫啉品系和敏感品系主要解毒酶活性比较

Comparison of activities of detoxic enzymes in the imidacloprid-resistant and susceptible strains of the cotton aphid, Aphis gossypii

通过生物测定和生物化学方法比较了棉蚜Aphisgossypii对吡虫啉抗性 (约为 7倍 )和敏感品系几种主要解毒酶的活性。结果表明 :氧化胡椒基丁醚对两个品系均无明显增效作用。抗性品系中羧酸酯酶和谷胱甘肽S 转移酶的比活力均明显高于敏感品系 ,抗性品系中羧酸酯酶的Km 值也显著高于敏感品系 ,说明抗性品系羧酸酯酶与底物的亲和力明显高于敏感品系。上述结果证明羧酸酯酶和谷胱甘肽S 转移酶活力增强在棉蚜对吡虫啉的抗性中起重要作用。

The activities of two metabolic enzymes in the imidacloprid resistant (about 7 fold) and susceptible strains of the cotton aphid, Aphis gossypii were compared by biochemical methods. Piperonyl butoxide (Pb) had no synergism to imidacloprid in both of the strains. Activities of carboxylesterases (CarE) and gluathione S transferases (GSTs) in the resistant strain were significantly higher than that in the susceptible one. The K m of CarE in the resistant strain were also significantly higher than in the susceptible strain, which means that the resistant strain had higher affinity of CarE with the substrate. The results showed that the enhancement of activities of CarE and GSTs would be the main metabolic mechanism in the resistance of A. gossypii to imidacloprid.