El-Garj F M A, Avicor S W, Wajidi M F F
Molecular Entomology Research Group, School of Distance Education, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
Trop Biomed. 2016 Sep 1;33(3):409-419.
Synthetic insecticides and other xenobiotic compounds are usually used to abate the effects of insect pests/vectors of agricultural and medical importance by adversely affecting the insects. The xenobiotics are also capable of inducing the expression of detoxification genes such as the cytochrome P450 (CYP) gene in targeted insects like mosquitoes (Feyereisen, 2012). The high expression levels of CYPs in insecticide-resistant and exposed mosquitoes have been linked with a potential role in xenobiotic resistance. This study investigated the induction potential of leaf litter infusions and insecticides on the expressions of CYP4H28v2 and CYP4H31v2 in the dengue mosquito Aedes aegypti using Reverse Transcription-quantitative Polymerase Chain Reaction. Exposure of Ae. aegypti larvae to leaf litter infusions demonstrated that CYP4H28v2 and CYP4H31v2 were significantly induced by Lagerstroemia speciosa but not Ficus benjamina, Plumeria obtusa, Millettia pinnata and Pithecellobium dulce. None of the genes was significantly highly expressed in adult females exposed to d-allethrin and d-trans allethrin products. CYP4H28v2 was significantly induced in Ae. aegypti exposed to DDT, malathion and permethrin for both 5 and 10 min. DDT, malathion and permethrin significantly induced CYP4H31v2 only in Ae. aegypti exposed to the insecticides for 10 min. Exposure to the insecticides for 5 min displayed different levels of CYP4H31v2 expression with significantly higher (DDT-exposed) and lower (permethrin-exposed) levels in the mosquito. The results show that natural and synthetic xenobiotics can induce significant expression of CYP4H28v2 and CYP4H31v2 in the mosquito, indicating the potential role of the genes in mediating xenobiotic resistance. This may enhance the survival capabilities of the mosquito when in contact with phytotoxins of leaf litter in their natural ecosystem and synthetic insecticides in adulticide spray regimens.
合成杀虫剂和其他外源化合物通常通过对昆虫产生不利影响来减轻农业和医学上重要的害虫/病媒的影响。这些外源化合物还能够诱导目标昆虫（如蚊子）中解毒基因的表达，如细胞色素P450（CYP）基因（费耶雷森，2012年）。抗杀虫剂和接触过杀虫剂的蚊子中CYP的高表达水平与对外源化合物的抗性潜在作用有关。本研究使用逆转录定量聚合酶链反应研究了落叶浸出液和杀虫剂对登革热媒介埃及伊蚊中CYP4H28v2和CYP4H31v2表达的诱导潜力。埃及伊蚊幼虫接触落叶浸出液表明，紫薇叶浸出液可显著诱导CYP4H28v2和CYP4H31v2的表达，但小叶榕、钝叶鸡蛋花、羽叶金合欢和猴耳环叶浸出液则不能。在接触右旋烯丙菊酯和反式右旋烯丙菊酯产品的成年雌性蚊子中，这些基因均未显著高表达。在接触滴滴涕、马拉硫磷和氯菊酯5分钟和10分钟的埃及伊蚊中，CYP4H28v2均显著诱导。滴滴涕、马拉硫磷和氯菊酯仅在接触杀虫剂10分钟的埃及伊蚊中显著诱导CYP4H31v2。接触杀虫剂5分钟时，蚊子中CYP4H31v2表达水平不同，接触滴滴涕的蚊子中表达水平显著较高，接触氯菊酯的蚊子中表达水平显著较低。结果表明，天然和合成的外源化合物可诱导蚊子中CYP4H28v2和CYP4H31v2的显著表达，表明这些基因在介导对外源化合物的抗性中具有潜在作用。这可能会增强蚊子在自然生态系统中接触落叶植物毒素和在杀虫剂喷洒方案中接触合成杀虫剂时的生存能力。
