5-氨基乙酰丙酸对中华稻蝗（Oxya chinensis）的杀虫活性及对3种酶活性的影响

 【目的】研究5-氨基乙酰丙酸（5-aminolevulinic acid，ALA）对中华稻蝗（Oxya chinensis）的杀虫活性及对3种酶活性的影响。【方法】以中华稻蝗4龄若虫为试验材料，用不同剂量的ALA（A1：250 mmol?L-1；A2：450 mmol?L-1；A3：750 mmol?L-1；A4：1 000 mmol?L-1）处理中华稻蝗，观察其对中华稻蝗的毒性效应和对其体内乙酰胆碱酯酶（AChE）、谷胱甘肽S-转移酶（GSTs）和谷胱甘肽过氧化物酶（GPx）活性的影响。【结果】不同剂量ALA处理组中华稻蝗死亡率依处理剂量呈现上升趋势，高浓度处理组A3、A4的死亡率分别达到66.19%和80.21%；LD50值为3.61（3.29～3.93）mg?g-1虫重（95%置信范围）。生化研究结果显示，最高浓度A4处理组雌、雄虫体内AChE活性分别较对照组下降了51.53%和42.65%，差异显著（P＜0.05）；GPx活性分别较对照组下降了42.82%和43.85%，差异显著（P＜0.05）。同时，中华稻蝗GSTs活性随ALA处理剂量升高而增高，A4处理组雌、雄虫体内GSTs活性分别较对照组升高了171.05%及97.42%，差异显著（P＜0.05）。【结论】ALA对雌、雄中华稻蝗均有明显的毒性效应；ALA可引起AChE和GPx光失活，从而导致中华稻蝗神经传导受阻同时抵御氧化损伤的能力下降；高剂量ALA激活GSTs，可引发昆虫对光毒性物质的自身反馈抵御反应。

Insecticidal Activities of 5-Aminolevulinic Acid on Oxya chinensis and Effect on Three Kinds of Enzymes

Fourth-instar nymphs of Oxya chinensis were treated (48h: 14h/3h/31h, dark/illumination/nature) with different dose 5-aminolevulinic acid (ALA) (A1:250mM; A2:450mM; A3:750Mm; A4: 1000mM)，the activities of Acetylcholinesterase (AChE), Glutathione S-transferase (GSTs) and Glutathione peroxidase (GPx) of Oxya chinensis were determinated. The results showed that the mortality of Oxya chinensis increased with increasing dose of ALA. The mortality of high-dose treatments A3, A4 reached 66.19%, 80.21%. Biochemical studies showed that ALA inhibited AChE and GPx activities of Oxya chinensis，the AChE activities of female and male Oxya chinensis in A4 treatment declined 51.53%, 42.65% significantly (P<0.05); the GPx activities of female and male Oxya chinensis in A4 treatments declined 42.82%; 43.85% compared to control respectively(P<0.05). Meanwhile, GSTs activities of Oxya chinensis increased with increasing dose of ALA，the GSTs activities of female and male Oxya chinensis in A4 treatment remarkably increased 171.05%, 97.42% compared to control(P<0.05). The results indicated that ALA had obviously toxic effect on Oxya chinensis. The reasons causing Oxya chinensis dead analyzed, ALA could inhibit AChE and GPx activities of Oxya chinensis which caused nerve transmission blocking and the capabilities to defend oxidation damage declining. Meanwhile high-dose ALA could activate GSTs which caused a feedback inhibition of insect to the phototoxic substance.