3种杀虫剂对杨树羧酸酯酶的抑制效果

Inhibition effect of three insecticides on carboxylesterase from poplar

研究了酶浓度、底物浓度、反应体系pH、反应温度、反应时间5个因素对美洲黑杨羧酸酯酶(CarE)活性测定的影响,得出测定杨树CarE的最适反应条件为:酶稀释10倍,底物浓度为3×10-4mol/L,pH为7.0,温度30℃,时间15 min。利用试验得到的反应最适条件分析了氧化乐果、吡虫啉和氟虫腈3种内吸性药剂对杨树CarE活性的影响。结果表明:400、1 600、3 200和6 400mg/L氧化乐果能明显抑制杨树CarE活性,其中6 400 mg/L氧化乐果抑制作用最强。50、100、200、400和800 mg/L吡虫啉处理杨树48 h,对杨树CarE均没有显著影响;当处理96 h时,400和800 mg/L吡虫啉能显著抑制CarE活性。而400 mg/L氟虫腈处理杨树48 h,800 mg/L氟虫腈处理杨树96 h,都能显著抑制杨树CarE活性。

The optimum reaction condition of carboxylesterase in poplar was studied using the biochemistry methods.The results indicated that the optimum enzyme dilution factor of carboxylesterase was 10,and the optimum substrate concentration was 3×10-4 mol/L,the optimum pH value was 7.0,and the optimum reaction time was 15 min,and the optimum temperature 30 ℃,for carboxylesterase in poplar.Furthermore,the effect on carboxylesterase from poplar by omethoate,imidacloprid and fipronil was determined.The results showed that carboxylesterase activity of poplar was inhibited by 400,1 600,3 200 and 6 400 mg/mL omethoate,and the inhibition effect of 6 400 mg/mL omethoate was strongest.The carboxylesterase activity of poplar didn＇t change,after being treated by 50,100,200,400 and 800 mg/mL imidacloprid for 48 h,and the activity decreased by 400 and 800 mg/mL imidacloprid for 96 h.The carboxylesterase activity of poplar decreased after being treated by 400 mg/mL fipronil for 48 h,and by 800 mg/mL fipronil for 96 h.