Comparison of biochemical characterizations of AChE in the larvae of three populations of Tribolium castaneum (Herbst): Implications of insecticide resistance
首发时间:2009-03-10
Abstract:The toxicological and biochemical characteristics of acetylcholinesterase (AChE) in two field and one laboratory populations of Tribolium castaneum larvae were investigated. The two field populations HSTC-R (higher level resistance) and HYTC-R (lower level resistance) were both resistant to phosphine as well as organophosphorus insecticides such as dichlorvos and malathion. Compared with the laboratory population (ABTC-S), the activities per insect and specific activities of AChE in HSTC-R and HYTC-R were significantly lower. The apparent Michaelis–Menten constant value (Km) for acetylthiocholine iodide (ATChI) was obviously lower in ABTC-S than that in HSTC-R, indicating a higher affinity to the substrate ATChI in the laboratory population. The affinity for the substrate ATChI in HYTC-R and ABTC-S were not significantly different. The Vmax value of the HSTC-R was significantly greater compared to the Vmax for the ABTC-S suggesting a possible over expression of AChE in this field population. The inhibition study of AChE to insecticide exposure in vitro revealed that all the inhibitors possessed excellent effect. For the efficiencies of the tested inhibitors, the rank order from the most sensitive to the least was eserine, followed by malaoxon, paraoxon-ethyl, carbaryl, and demeton-S-methyl. Based on the I50s, AChE of the ABTC-S were more sensitive to all the inhibitors than those of HSTC-R. The statistical analysis of the bimolecular rate constants (ki) was consistent with the above situation. It is concluded that the insensitive AChEs were probably involved in the resistance of T. castaneum against insecticides observed in the field populations.
keywords: Tribolium castaneum acetylcholinesterase biochemistry resistance
点击查看论文中文信息
赤拟谷盗3个种群幼虫乙酰胆碱酯酶生化特性比较研究
摘要:本文对赤拟谷盗1个室内种群和2个室外种群幼虫乙酰胆碱酯酶(AChE)的毒理学和生化特性进行了较为系统比较研究。室外种群HSTC-R和HYTC-R分别为高抗品系和低抗品系,对磷化氢和有机磷杀虫剂如敌敌畏、马拉硫磷均具有一定的抗性。研究结果表明,HSTC-R和HYTC-R幼虫AChE的活性和比活力显著低于室内种群ABTC-S。就米氏常数(Km)而言,ABTC-S明显低于HSTC-R,说明室内种群幼虫AChE对底物的亲和力显著高于HSTC-R种群,而HYTC-R 和 ABTC-S两个种群幼虫AChE对底物的亲和力则无显著性差异。与ABTC-S种群相比,HSTC-R种群幼虫AChE的Vmax显著更高,暗示该种群幼虫体内乙酰胆碱酯酶可能过量表达。此外,杀虫剂对AChE的离体作用研究表明测定的几种抑制剂对赤拟谷盗幼虫AChE均有抑制作用。以抑制中浓度I50为测定指标,5种抑制剂的抑制作用从高到低依次为:毒扁豆碱 > 马拉氧磷 > 对氧磷 > 西维因 > 甲基内吸磷。与HSTC-R种群相比,ABTC-S种群幼虫体内的AChE对上述5种抑制剂更为敏感。双分子速率常数(Ki)的统计分析结果与上述结果一致。由此可以推断,AChE敏感性下降可能与赤拟谷盗对杀虫剂的抗性形成有关。
论文图表:
引用
No.3007144803123667****
同行评议
共计0人参与
勘误表
赤拟谷盗3个种群幼虫乙酰胆碱酯酶生化特性比较研究
评论
全部评论0/1000