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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。
Pesticide resistance refers to “the ability of a strain of organisms to develop a pesticidal dose that is lethal to the most individuals in the normal population of the organism.” Resistance mechanisms such as behavioral changes, physiologic changes, or metabolic detoxification can reduce the effective dose of a poison to a target. Behavioral resistance refers to any action that reduces the contact of an insect with a poison or enables the insect to survive in an environment that is lethal (or detrimental) to most normal individuals. Mechanisms of physiological change include the reduced penetration of pesticides into the epidermis, increased sequestration of drug agents or storage and accelerated excretion of pesticides. Cytochrome P450, hydrolase and glutathione S-transferase are the three major enzymes that metabolize and detoxify pesticides. Cytochrome P450 is a super-gene family and is the most important enzyme in the organism that detoxifies or activates exogenous and endogenous compounds. P450-mediated increase in detoxification metabolism was found in many pests resulting in increased resistance to insecticides. Glutathione S-transferase, a soluble dimeric protein, is involved in metabolic detoxification and the excretion of a large number of endogenous and exogenous compounds. Many insects have demonstrated that their resistance is associated with increased enzyme activity. Hydrolases are actually a group of heterologous enzymes whose resistance to action includes increasing the amount of enzyme by gene amplification, isolating the insecticide as a binding protein, or enhancing the hydrolysis of the agent by increasing the activity of the enzyme.