Basic studies on the insect cytochrome P450 for the development of new insecticides and synergistic agents.

为了寻找新的杀虫剂或增效剂的作用靶点，本文对媒介蚊虫的抗药性机制进行了研究，特别是对媒介蚊虫细胞色素P450单加氧酶的功能进行了分析。首先，在实验室中用氯菊酯（拟除虫菊酯类杀虫剂）选择成蚊。经过8代的选择，蚊子（SPS 8株）的抗性水平达到1000倍以上的杀虫剂敏感株相比。由于氯菊酯的敏感性大大增加与胡椒基丁醚预处理的蚊子，有人建议，细胞色素P450单加氧酶的抗性中发挥主要作用。体外代谢研究表明，抗性蚊的微粒体蛋白<14>比敏感蚊的微粒体蛋白更快地催化α-C-二氯苯醚菊酯代谢为4 'HO-二氯苯醚菊酯。此外，氯菊酯羟化活性是NADPH依赖性的，并强烈抑制胡椒基丁醚强烈表明，细胞色素P450单加氧酶参与氯菊酯抗性的SPS 8菌株。与氯菊酯抗性相关的P450异构体是作为杀虫剂或增效剂的新靶点的有希望的候选者。对2009年从新加坡采集的26只白纹伊蚊成虫进行钠通道基因分型。令人惊讶的是，超过70%的蚊子拥有敲除抗性（kdr）基因。这是白纹伊蚊kdr基因存在的第一个证据，并建议需要研究这个等位基因在这个重要的媒介昆虫的全球分布。

In order to seek novel target sites of insecticides or synergists, I studied on the mechanisms of insecticide resistance in vector mosquitoes, especially on the functional analysis of their cytochrome P450 monooxygenases. First of all, adult mosquitoes were selected in the laboratory with permethrin which is a class of pyrethroid insecticides. After the selections for 8 generations, the resistance level of mosquitoes (SPS8 strain) reached more than 1000-fold compared to an insecticide susceptible strain. Since permethrin susceptibility largely increased with pre-treatment of mosquitoes with piperonyl butoxide, it was suggested that cytochrome P450 monooxygenases have the major role in the resistance. In vitro metabolism study revealed that microsomal protein prepared from resistant mosquitoes catalyzed metabolism of ^<14>C-permethrin more rapidly to 4'HO-permethrin than that of a susceptible strain. Furthremore, permethrin hydroxylation activity was NADPH dependent and was strongly inhibited by piperonyl butoxide strongly suggested that cytochrome P450 monooxygenases are involved in permethrin resistance in SPS8 strain. The P450 isofoms which are associated with permethrin resistance are promising candidates as novel target sites of insecticides or synergists. Sodium channel gene was genotyped for 26 adult Aedes albopictus collected from Singapre in 2009. Surprisingly, more than 70% of mosquitoes possessed the knockdown resistance (kdr) gene. This is the first evidence for the presence of the kdr gene in Aedes albopictus and suggests the need to study the global distribution of this allele in this important vector insect.