运用α-氰代酯荧光底物检测抗性棉蚜羧酸酯酶代谢活性

为了研究抗性和敏感棉蚜Aphis gossypii品系对菊酯类药剂代谢的差异, 本实验合成了溴氰菊酯和高效氯氰菊酯报告荧光底物, 应用这两种底物水解后生成具有荧光化合物的特性，测定了不同品系棉蚜羧酸酯酶的代谢活性。结果表明: 氧化乐果棉蚜抗性和敏感品系羧酸酯酶对溴氰菊酯报告荧光底物的代谢活性分别为10.0和3.4 pmol/min·mg; 对高效氯氰菊酯报告荧光底物的代谢活性分别为4.0和2.4 pmol/min·mg, 抗性品系羧酸酯酶对溴氰菊酯和高效氯氰菊酯报告荧光底物的代谢活性分别为敏感品系的2.9和1.7倍; 溴氰菊酯棉蚜抗性和敏感品系羧酸酯酶对溴氰菊酯报告荧光底物的代谢活性分别为7.6和6.2 pmol/min·mg; 对高效氯氰菊酯报告荧光底物的代谢活性分别为9.3和5.2 pmol/min·mg, 抗性品系羧酸酯酶对溴氰菊酯和高效氯氰菊酯报告荧光底物的代谢活性分别为敏感品系的1.2和1.8倍。这种衍生的报告荧光底物能够用来检测抗性棉蚜羧酸酯酶的水解活性, 表明羧酸酯酶可能参与棉蚜对溴氰菊酯和氧化乐果抗性的形成。

Application of α-cyanoesters as fluorescent substrates for examining metabolic activity of carboxylesterases in cotton aphid, Aphis gossypii (Homoptera: Aphididae)resistant to pesticides

In order to clarify the difference of pyrethroid metabolosim between resistant and susceptible strains, deltamethrin and cypermethrin reporter fluorescent substrates with fluorescent characteristics after hydrolysis were synthesized and used to assay carboxylesterase metabolic activities in different strains of cotton aphid, Aphis gossypii. The results showed that the specific carboxylesterase activities to deltamethrin reporter fluorescent substrate were 10.0 and 3.4 pmol/min·mg in the omethoate-selected resistant and susceptible strains of cotton aphid, respectively, while those to cypermethrin reporter fluorescent substrate were 4.0 and 2.4 pmol/min·mg, respectively. The carboxylesterase activity in the omethoate-selected resistant strain was 2.94- and 1.67- fold compared with that in the susceptible strain when using deltamethrin and cypermethrin reporter fluorescent substrates, respectively. However, the specific carboxylesterase activities to deltamethrin reporter fluorescent substrate were 7.6 and 6.2 pmol/min·mg in the deltamethrin-selected resistant and susceptible strains of cotton aphid, respectively, while those to cypermethrin reporter fluorescent substrate were 9.3 and 5.2 pmol/min·mg, respectively. The carboxylesterase activity in the deltamethrin-selected resistant strain was 1.23- and 1.79-fold compared with that in the susceptible strain when using deltamethrin and cypermethrin reporter fluorescent substrates, respectively. The surrogates for pyrethroids can be used to monitor carboxylesterase hdyrolytic activity of resistant cotton aphids, suggesting that carboxylesterases may be involved in deltamethrin and omethoate resistance in cotton aphids.