关键词: 白纹伊蚊, 重金属, 镉胁迫, 海藻糖, 海藻糖代谢

Abstract: 【Aim】 This study aims to understand the toxic effects of cadmium on Aedes albopictus and its adaptation to the extreme environment, and to reveal the possible effects of heavy metal stress on the occurrence of mosquitoes and disease transmission, so as to provide reference for the control of hygienic pests. 【Methods】 The late 3rd instar to early 4th instar larvae of A. albopictus with the same growth status in 320 mL disposable cups were acutely exposed to 200 mL prepared 50, 100, 200, 300, and 400 mg/L Cd²⁺ solution, respectively, for 12 h, and the larvae cultured in double distilled water were used as the control. The contents of trehalose, sucrose and total glycogen, and the activities of soluble trehalase (TRE1) and membrane-bound trehalase (TRE2) in the larvae at 12 h post treatment were determined by biochemical methods, and the relative expression levels of trehalose-6-phosphate synthase gene (TPS), TRE1 and TRE2 in these larvae were detected by qRT-PCR. 【Results】 The results showed that the trehalose content in A. albopictus larvae exposed to 200 and 300 mg/L Cd²⁺ solution for 12 h increased significantly, while the glucose content in larvae exposed to high concentrations of Cd²⁺ solution (300 and 400 mg/L) decreased significantly, as compared with the control. The acute treatment of different Cd²⁺ concentrations had no effect on the total glycogen content. The activities of TRE1 and TRE2 in larvae exposed to high concentrations of Cd²⁺ (300 and 400 mg/L) decreased significantly as compared with those in the control group. The relative expression level of TPS was the highest in the 300 mg/L Cd²⁺ treated group. The relative expression levels of TRE1 and TRE2 in larvae exposed to high concentrations of Cd²⁺ solution (300 and 400 mg/L) decreased significantly as compared with those in the control group. 【Conclusion】 The acute stress of Cd²⁺ up-regulates the expression of TPS gene in A. albopictus larvae when the Cd²⁺ concentration is lower than the LC₅₀ value (217 mg/L), while the relative expression level of TRE gene and the TRE activity decrease,  thereby promoting the conversion of glucose to trehalose and resisting the Cd²⁺ stress by the production of trehalose. These results indicate that trehalose may play a role in heavy metal stress in A. albopictus larvae, which can improve the resistance to Cd²⁺ stress by trehalose synthesis.

Key words: Aedes albopictus, heavy metal, cadmium stress, trehalose, trehalose metabolism