有机磷类杀虫剂代谢机制研究进展

文章对有机磷类杀虫剂代谢机制的研究进展以及昆虫对此类杀虫剂的相关代谢抗性机制进行了总结,阐述了有机磷杀虫剂的生物代谢途径及相关代谢酶系。在生物体中,有机磷类杀虫剂主要发生氧化代谢、水解代谢和轭合代谢等反应。其氧化代谢主要在细胞色素P450酶系(P450s)的催化作用下进行,其中,最重要的氧化反应是硫代有机磷酸酯类杀虫剂氧化脱硫形成生物毒性更高的有机磷氧化物的反应,以及氧化脱芳(烷)基化的反应;有机磷杀虫剂及其氧化产物在生物体内还可发生水解代谢反应,在对氧磷酶PON1等磷酸三酯酶的催化作用下,水解生成低毒性或者无毒的代谢物;有机磷杀虫剂的轭合代谢主要是在谷胱甘肽硫转移酶(GSTs)的催化下进行的。昆虫对有机磷类杀虫剂的代谢抗性与昆虫中参与此类杀虫剂代谢的解毒酶的改变密切相关,其中,与有机磷类杀虫剂代谢相关的P450s基因的过量表达和酶活性增强、丝氨酸水解酯酶的过量表达及基因突变、GSTs基因的过量表达等,均可导致铜绿蝇Lucilia cuprina、桃蚜Myzus persicae等昆虫对二嗪磷和马拉硫磷等有机磷类杀虫剂的代谢抗性。明确有机磷类杀虫剂的结构特点、代谢途径以及昆虫对此类杀虫剂的代谢抗性机制,对掌握有机磷类杀虫剂的毒理学机制,安全有效地使用此类杀虫剂,有效治理害虫对有机磷类杀虫剂的抗药性,以及开发生物选择性好的新型有机磷类杀虫剂,均具有重要意义。

Research progresses on the metabolic mechanisms of organophosphate insecticides

The research progresses related to metabolic mechanisms of organophosphates(OPs) and metabolic resistance mechanisms of insects to organophosphates were summarized. The metabolic pathways of OPs in organisms and the metabolic enzymes involved in were described. OPs mainly experienced oxidation, hydrolysis and conjugation in organisms. The oxidation of OPs mainly occurred under the catalysis of cytochrome P450s. The most important oxidation reactions of OPs are desulfuration of organophosphorothioates(OPTs) to form organophosphate oxons, which exhibit higher toxicity to organisms than native OPTs, and dealkylation or dearylation of OPs. The OPs and its oxons could be hydrolyzed in organisms under the catalysis of phosphotriesterase including paraoxonase(PON1), and low toxic or non-toxic metabolites were produced. The conjunction of OPs is mainly catalyzed by glutathione S-transferases(GSTs). Changes in the metabolic ability to OPs in insects resulted in metabolic resistance. Gene overexpression or higher activity of cytochrome P450s, overexpression or gene mutation of esterases, and overexpression of glutathione S-transferases gene were related to the improved metabolism of OPs and contributed to the metabolic resistance to OPs such as diazinon and malathion in insects including Lucilia cuprina, Myzus persicae. Clarifying the metabolic mechanisms of OPs on the basis of OPs structures, metabolic pathways, the corresponding detoxification enzymes involved in, and the metabolic resistance mechanisms of OP-resistant insects, are very important for understanding the metabolic toxicology of OPs, safe and efficient application of OPs, controlling the OP-resistant insects, exploring and developing novel OPs with better bio-selectivity.