Cytochrome P450 associated with insecticide resistance catalyzes cuticular hydrocarbon production in Anopheles gambiae
Cytochrome P450 associated with insecticide resistance catalyzes cuticular hydrocarbon production in Anopheles gambiae
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DOI：
10.1073/pnas.1608295113
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发表时间：
2016-08-16
影响因子：
11.1
通讯作者：
Vontas, John
中科院分区：
文献类型：
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作者：
Balabanidou, Vasileia;Kampouraki, Anastasia;Vontas, John
评估了主要疟疾媒介冈比亚按蚊表皮变化在杀虫剂抗性中的作用。抗性品系中C-14溴氰菊酯的内化速率显著低于敏感品系。局部应用丙酮杀虫剂配方，以规避脂质为基础的吸收障碍，降低了电阻率约50%。通过电子显微镜和脂质提取物表征的表皮分析表明，抗性蚊子具有较厚的表皮层和表皮碳氢化合物（CHC）含量的显着增加（类似于29%）。然而，CHC在抗性和敏感昆虫中的谱和相对分布相似。对两种P450酶CYP 4G 16和CYP 4G 17的细胞定位和体外活性进行了分析，CYP 4G 16和CYP 4G 17的基因在抗性按蚊中经常过表达。这些酶是分别催化果蝇和家蝇中CHC生物合成的最后步骤的CYP 4G 1/2酶的潜在直系同源物。免疫染色表明，CYP 4G 16和CYP 4G 17在被认为分泌烃类的昆虫细胞类型的卵母细胞中高度丰富。然而，显示了一个有趣的差异; CYP 4G 17在整个细胞中出现，与微粒体P450的预期一致，但CYP 4G 16定位于细胞的外周，位于细胞膜的细胞质侧，这是P450酶的独特位置。CYP 4G 16和CYP 4G 17在昆虫细胞中功能性表达。CYP 4G 16从C18醛底物产生烃，因此具有与dmCYP 4G 1/2相似的真正的脱羰基酶活性。这些数据支持以下假设：在对拟除虫菊酯高度耐药的按蚊中，发生了包括表皮屏障在内的多种机制的协同进化。冈比亚。
The role of cuticle changes in insecticide resistance in the major malaria vector Anopheles gambiae was assessed. The rate of internalization of C-14 deltamethrin was significantly slower in a resistant strain than in a susceptible strain. Topical application of an acetone insecticide formulation to circumvent lipid-based uptake barriers decreased the resistance ratio by similar to 50%. Cuticle analysis by electron microscopy and characterization of lipid extracts indicated that resistant mosquitoes had a thicker epicuticular layer and a significant increase in cuticular hydrocarbon (CHC) content (similar to 29%). However, the CHC profile and relative distribution were similar in resistant and susceptible insects. The cellular localization and in vitro activity of two P450 enzymes, CYP4G16 and CYP4G17, whose genes are frequently overexpressed in resistant Anopheles mosquitoes, were analyzed. These enzymes are potential orthologs of the CYP4G1/2 enzymes that catalyze the final step of CHC biosynthesis in Drosophila and Musca domestica, respectively. Immunostaining indicated that both CYP4G16 and CYP4G17 are highly abundant in oenocytes, the insect cell type thought to secrete hydrocarbons. However, an intriguing difference was indicated; CYP4G17 occurs throughout the cell, as expected for a microsomal P450, but CYP4G16 localizes to the periphery of the cell and lies on the cytoplasmic side of the cell membrane, a unique position for a P450 enzyme. CYP4G16 and CYP4G17 were functionally expressed in insect cells. CYP4G16 produced hydrocarbons from a C18 aldehyde substrate and thus has bona fide decarbonylase activity similar to that of dmCYP4G1/2. The data support the hypothesis that the coevolution of multiple mechanisms, including cuticular barriers, has occurred in highly pyrethroid-resistant An. gambiae.