昆虫抗药性机理:行为和生理改变及解毒代谢增强(英文)

Behavioral change, physiological modification, and metabolic detoxification: mechanisms of insecticide resistance

杀虫剂抗性是指“生物的一个品系发展了对该生物正常种群中大多数个体具有致死作用剂量的杀虫药剂的能力”。行为改变、生理学上的变化或代谢解毒等抗性机制能够降低毒物到达靶标的有效剂量。行为抗性是指减少昆虫与毒物接触或使昆虫能够存活于对大多数对正常个体致死(或有害)的环境中的任何行为。生理学改变的机制包括杀虫剂对表皮的穿透性降低、增加对药剂阻隔(sequestration)或储存和加速杀虫剂的排泄。细胞色素P450、水解酶和谷胱甘肽S转移酶是杀虫药剂代谢解毒的主要3大酶系。细胞色素P450是一个超基因家族,是生物体内对外源性和内源性化合物解毒代谢或活化最重要的酶系。在许多害虫中发现P450介导的解毒代谢增加导致了对杀虫药剂抗性的增加。谷胱甘肽S转移酶是可溶性的二聚体蛋白,与代谢解毒、大量内源性和外源性化合物的排泄有关,许多昆虫中证明其抗药性与该酶活性增加有关。水解酶实际上是一组异源的酶类,其对抗药性的作用包括通过基因扩增增加酶量,作为结合蛋白隔离杀虫药剂或通过增加酶的活性加强对药剂的水解作用。

Insecticide resistance is ＂the development of an ability in a strain of some organisms to tolerate doses of a toxicant which would prove lethal to a majority of individuals in a normal population of the same species＂. Mechanisms of resistance, such as behavioral change, physiological modification or metabolic detoxification, decrease the effective dose available at the target site. Behavioral resistance is defined as any behavior that reduces an insect＇s exposure to toxic compounds or that allows an insect to survive in an environment that is harmful and/or fatal to the majority of insects. Physiological modification mechanisms permit insects to survive lethal doses of a toxicant through decreased penetration of insecticides, increased sequestration/storage of insecticides, and accelerated excretion of insecticides. Metabolic detoxification is conferred by cytochrome P450 monooxygenases （cytochrome P450s ）, hydrolases, and glutathione transferases （GSTs）. Cytochrome P450s constitute the largest gene superfamily and are critical for the detoxification and/or activation of xenobiotics and the metabolism of endogenous compounds. Increased P450-mediated detoxification has been found in many insect species, resulting in enhanced insecticide resistance. Glutathione transferases （GSTs） are soluble dimeric proteins involved in the metabolism, detoxification, and excretion of a large number of endogenous and exogenous compounds. Elevated GST activities have been implicated in resistance in many insect species. Hydrolases or esterases, a group of heterogeneous enzymes, have been identified as the active agents promoting hydrolase-mediated resistance that protect insects by either binding and sequestering insecticides through overproduction of proteins, or enhancing the metabolism of insecticides through increased enzyme activities.