Mechanisms of pyrethroid resistance in the dengue mosquito vector, Aedes aegypti: target site insensitivity, penetration, and metabolism.
Mechanisms of pyrethroid resistance in the dengue mosquito vector, Aedes aegypti: target site insensitivity, penetration, and metabolism.
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DOI：
10.1371/journal.pntd.0002948
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发表时间：
2014-06
影响因子：
3.8
通讯作者：
Tomita T
中科院分区：
文献类型：
--
作者：
Kasai S;Komagata O;Itokawa K;Shono T;Ng LC;Kobayashi M;Tomita T
埃及伊蚊是黄热病和登革热的主要传播媒介。经过 10 代成虫选择后，埃及伊蚊菌株 (SP) 对氯菊酯产生了 1650 倍的抗性，氯菊酯是用于蚊子控制的最广泛使用的拟除虫菊酯杀虫剂之一。 SP幼虫在选择成虫后也产生了8790倍的抗性。选择之前，电压敏感钠通道（Vssc，拟除虫菊酯杀虫剂的靶位点）II域和III域中V1016G和F1534C突变的频率分别为0.44和0.56。相反，在两次氯菊酯选择后仅存在 G1016 等位基因，表明 G1016 比 C1534 更能导致 Vssc 不敏感。体内代谢研究表明，SP 菌株比易受影响的 SMK 菌株更快地排泄氯菊酯代谢物。用胡椒基丁醚预处理可强烈抑制氯菊酯代谢物的排泄，表明细胞色素 P450 单加氧酶 (P450s) 在抗性发展中发挥重要作用。体外代谢研究还表明 P450 与耐药性相关。微阵列分析表明，SP菌株的幼虫和成虫阶段有多个P450基因过度表达。在定量实时 PCR 之后，我们重点关注两种 P450 同工型：CYP9M6 和 CYP6BB2。这些 P450 的转录水平与氯菊酯的排泄率密切相关，并且它们确实能够将氯菊酯解毒为 4'-HO-氯菊酯。 CYP9M6 的过度表达部分是由于基因扩增。 SP和SMK菌株之间角质层氯菊酯减少率没有显着差异。 埃及伊蚊栖息在世界各地的热带和亚热带地区，是登革热和黄热病的主要媒介，也是基孔肯雅热的次要媒介。登革热在 110 多个国家流行，每年造成多达 1 亿人感染。由于目前没有有效的疫苗或药物，病媒控制仍然是减少这种疾病病例数量的主要解决方案，并且在很大程度上依赖于杀虫剂的使用。杀虫剂的大量和长期使用导致世界范围内出现了对这些化学物质具有抗药性的蚊子。在这里，我们新鉴定了两种 P450，它们具有对拟除虫菊酯杀虫剂解毒的能力，并且在抗性埃及伊蚊菌株中过量产生。我们的研究表明至少有四种 P450 同工酶与耐药性和靶位点不敏感性相关。这些发现可能会导致在该领域开发更准确的监测系统，并有助于确定有效对抗抗性昆虫的杀虫剂的新目标位点。
Aedes aegypti is the major vector of yellow and dengue fevers. After 10 generations of adult selection, an A. aegypti strain (SP) developed 1650-fold resistance to permethrin, which is one of the most widely used pyrethroid insecticides for mosquito control. SP larvae also developed 8790-fold resistance following selection of the adults. Prior to the selections, the frequencies of V1016G and F1534C mutations in domains II and III, respectively, of voltage-sensitive sodium channel (Vssc, the target site of pyrethroid insecticide) were 0.44 and 0.56, respectively. In contrast, only G1016 alleles were present after two permethrin selections, indicating that G1016 can more contribute to the insensitivity of Vssc than C1534. In vivo metabolism studies showed that the SP strain excreted permethrin metabolites more rapidly than a susceptible SMK strain. Pretreatment with piperonyl butoxide caused strong inhibition of excretion of permethrin metabolites, suggesting that cytochrome P450 monooxygenases (P450s) play an important role in resistance development. In vitro metabolism studies also indicated an association of P450s with resistance. Microarray analysis showed that multiple P450 genes were over expressed during the larval and adult stages in the SP strain. Following quantitative real time PCR, we focused on two P450 isoforms, CYP9M6 and CYP6BB2. Transcription levels of these P450s were well correlated with the rate of permethrin excretion and they were certainly capable of detoxifying permethrin to 4′-HO-permethrin. Over expression of CYP9M6 was partially due to gene amplification. There was no significant difference in the rate of permethrin reduction from cuticle between SP and SMK strains. Aedes aegypti inhabits tropical and subtropical regions worldwide and is the major vector of dengue and yellow fevers, and a secondary vector of chikungunya fever. Dengue fever is epidemic in more than 110 countries and causes up to 100 million infections annually. As there is no efficient vaccine or medicine currently available, vector control remains the primary solution for reducing the number of cases of this disease and relies heavily on the use of insecticides. Intensive and long-term use of insecticides has resulted in the worldwide emergence of mosquitoes with resistance to these chemicals. Here we newly identified two P450s, which have the ability to detoxify pyrethroid insecticide and are over produced in the resistant A. aegypti strain. Our study showed there were at least four P450 isozymes associated with resistance and target site insensitivity. These findings may lead to the development of more accurate monitoring systems in the field and also assist to identify new target sites for insecticides that are effective against resistant insects.
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影响因子：
3.8
作者：
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通讯作者：
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作者：
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通讯作者：
Bromilow, Richard H.
影响因子：
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作者：
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通讯作者：
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