一个致倦库蚊杀虫剂敏感品系的筛选

化学防治是控制蚊虫传播疾病的主要方法, 抗性监测表明我国蚊虫已对有机磷、 有机氯、 氨基甲酸酯和拟除虫菊酯类杀虫剂产生了不同程度的抗性。蚊虫抗药性的分子机制主要包括靶标抗性和三大解毒酶家族带来的代谢抗性。筛选对杀虫剂敏感的品系是抗性监测和抗性机理研究必不可少的材料。本研究通过从一个致倦库蚊Culex pipiens quinquefasciatus野生种群筛选无乙酰胆碱酯酶G119S突变且具有低活性羧酸酯酶、 P450单加氧酶和谷胱甘肽-S-转移酶的单雌系, 建立了一个对杀虫剂敏感的致倦库蚊品系。该品系的羧酸酯酶活性是敏感品系S-lab的2.5倍, P450单加氧酶和谷胱甘肽-S-转移酶的活性与S-lab相当。生物测定表明, 与S-lab相比, 该品系对有机磷杀虫剂有低于2倍的抗性, 对氨基甲酸酯和拟除虫菊酯类杀虫剂没有抗性, 可以作为相对敏感品系用于抗性监测。

Screening of an insecticide-susceptible strain of Culex pipiens quinquefasciatus (Diptera: Culicidae)

Chemical control is the main method to control mosquitoes that are the primary vectors of human diseases. Previous resistance investigations showed that mosquitoes in China had become resistant to organophosphates, organochlorines, carbamates and pyrethroids. There are two main resistance mechanisms, i.e., the target resistance and the metabolism resistance that three detoxification enzyme families are involved in. An insecticide-susceptible strain is indispensable for resistance monitoring and studies of resistance mechanisms. In this study, we established an insecticide-susceptible strain of Culex pipiens quinquefasciatus from a field population by screening the isofemale lines without the G119S mutation in the acetylcholinesterase and with the low activity of carboxylesterases, P450 monooxygenases, and glutathione-S-transferases. Compared to another susceptible strain, S-lab, the strain screened here had 1.5-old higher carboxylesterase activity and equivalent P450 and glutathione-S-transferase activities. Insecticide bioassay showed that this strain had a less than 2-fold resistance to organophosphates and no resistance to carbamates and pyrethroids compared to the S-lab. Therefore this strain can be applied as an insecticide-susceptible strain in resistance monitoring.