【摘要】 测定了斜纹夜蛾酯酶的动力学参数,酯酶同工酶电泳和杀虫剂(溴氰菊酯和丙溴磷)对酯酶的抑制效应。结果表明,抗性品系与敏感品系酯酶的Km值之间均没有显著差异,但抗性品系酯酶的Vmax值比敏感品系的高且差异显著。在酯酶的非变性聚丙烯酰胺凝胶电泳图谱中,抗性品系中所含的酯酶同工酶条带数比敏感品系的多;溴氰菊酯浓度在12.5μmol/L时,对敏感品系酯酶的抑制率最大,约为30%,而对抗性品系酯酶的抑制率则随着溴氰菊酯浓度的升高而升高,溴氰菊酯浓度在50μmol/L时抑制率最大,约为75%;但是丙溴磷对抗、感品系的酯酶的抑制效应较为一致。上述结果说明在抗性品系中出现了与敏感品系不同的酯酶同工酶,但这些同工酶并没有显著改变抗性品系全酯酶的Km值,仅是增强了其酯酶活性,提高了对溴氰菊酯的代谢能力。更多还原

【Abstract】 The biochemical characteristics of esterase from the Deltamethrin-susceptible and Deltamethrin-resistant strains of Spodoptera litura,including kinetics,isozyme electrophoresis,inhibitory effects of Deltamethrin and Profenofos on esterase activity,were investigated.The results showed that the Km-values of general esterases in the Deltamethrin-resistant larvae were not statistically different from those in the Deltamethrin-susceptible larvae,but the Vmax values of general esterases hydrolyzing α-NA and β-NA in the resistant strain were significantly higher than those in the susceptible strain.Native PAGE showed that there were important differences in esterase bands between Deltamethrin-resistant and-susceptible strains,the susceptible S.litura intensely lacked some staining bands found in the resistant S.litura.Deltamethrin had differently inhibitory effects on esterase activity in susceptible and resistant strains.Approximately 70% esterase activity of the susceptible strain was not inhibited by Deltamethrin at a concentration of 12.5 μmol/L or more.However,at a concentration of 50 μmol/L and greater,approximately 75% of enzyme activity was inhibited.Profenofos bound strongly to both the resistant and susceptible enzymes.The above results showed that some isozymes of esterase were only found in the resistant strain other than in the susceptible strain,which had not changed the Km values of resistant esterases and just enhanced the enzyme activity to metabolize Deltamethrin.更多还原