本研究將埃及斑蚊對殺蟲劑敏感對照品系幼蟲(Bora-Bora品系)及對百滅寧抗性品系(苓雅抗性品系)幼蟲暴露於不同百滅寧稀釋藥液，以半定量PCR測定於不同暴露時間誘導之CYP9J27 、 CYP6AL1 、 CYP9M9 、 GSTe4 、 CCEae3o 及 Tpx2等七個基因的表現量。經百滅寧藥液誘導後 CYP6AL1 及 Tpx2 可以大量表現，苓雅抗性品系在暴露後第 4 小時大量表現，Bora-Bora 品系在暴露後第 16小時大量表現。CYP9M9 、 GSTe4 及 CCEae3o在不同品系間具有不同程度的表現，CYP9J27在兩個品系的基因表現量都是最低的。
以0.5µg/l 和 20µg/l 百滅寧藥液分別暴露誘導Bora-Bora 品系及苓雅抗性品系幼蟲，單氧酶的活性於暴露藥劑後第2及第6小時有較明顯的誘導效果，在苓雅抗性品系的誘導效果較明顯。穀胱苷肽硫基轉移酶活性於暴露藥劑後第0、第2及第6小時有較明顯的誘導效果，在苓雅抗性品系的誘導效果較明顯。暴露低濃度百滅寧藥液後6-10小時，可測得最高解毒酵素活性。
以 0.5µg/l 和 20µg/l 百滅寧藥液處理Bora-Bora品系及苓雅抗藥性品系，誘導組供試幼蟲明顯較未誘導對照組對百滅寧有較高的耐受性，當供試藥液含有8 mg/l的PBO藥液時，原先該被誘導對百滅寧的耐受性消失，死亡率比誘導組及未誘導對照組高。
本結果證實暴露於百滅寧藥液，確實會誘導解毒相關基因的表現，也會誘導增加解毒酵素活性，試驗結果顯示 P450 單氧酶酵素活性的誘導效果明顯高於穀胱苷肽硫基轉移酶的誘導效果。經誘導供試埃及斑蚊幼蟲會降低對百滅寧的感受性，當供試藥液中添加PBO可恢復斑蚊幼蟲對藥劑的感受性。 The effect of exposure of Aedes aegypti larvae to various concentration of the permethrin on their expression of detoxification gene was investigated. In the present study we used the semi-quantitative reverse-transcription polymerase chain reaction (RT-PCR) to determine several detoxification genes including CYP9J27, CYP6AL1, CYP9M9, GSTe4, CCEae3o and Tpx2. Band intensities of detoxification genes were normalized using the RPL17 housekeeping gene. We show that the CYP6AL1 and Tpx2 in Ae. aegypti were over expressed after permethrin exposed. The CYP6AL1 and Tpx2 were differentially transcribed in resistant LYPR strain and susceptible Bora-Bora strain at 4 h and 16 h after exposure to 0.5µg/l and 20µg/l of permethrin, respectively. The CYP9M9, GSTe4 and CCEae3o were showed various elevated mRNA levels after permethrin exposure. Within all tested genes, the expression level of CYP9J27 were lowest both in resistant and susceptible strains.
The monooxygenase and glutathione S-transferase activity were induced in Ae. aegypti larvae after 6-10 h exposure to 0.5µg/l and 20µg/l of permethrin.
Larvae tolerance to permethrin was moderately improved after exposure to sub-lethal dosage of permethrin. The PBO is an effective synergist with permethrin to weaken the detoxification enzyme elevated expression.
