Insecticidal activities and effects on three enzymic activities caused by 5-aminolevulinic acid （ALA） on Oxya chinensis were studied. Fourth-instar nymphs of O. chinensis were treated with different doses ofALA （A1...Insecticidal activities and effects on three enzymic activities caused by 5-aminolevulinic acid （ALA） on Oxya chinensis were studied. Fourth-instar nymphs of O. chinensis were treated with different doses ofALA （A1,250 mM; A2, 450 mM; A3,750 mM; A4, 1 000 mM）. Mortality and the activities of acetylcholinesterase （ACHE）, glutathione S-transferase （GSTs）, and glutathione peroxidase （GPx） were determinated. The mortality of O. chinensis rose with an increasing dose of ALA. The mortality of high-dose treatments A3 and A4 reached 66.19 and 80.21%, respectively. The value of LD50 was 3.61 （3.29-3.93） mg·g^-1 body weight （95% confidence interval）. Biochemical studies showed that the activities of AChE and GPx in the A4 treatment declined by 51.53 and 42.82% in the female, and 42.65 and 43.85% in the male compared to the control, respectively, and the degree of decline reached a significant level at P 〈 0.05. Meanwhile, the GSTs activities of O. chinensis enhanced with increasing dose of ALA. The GSTs activities of female and male O. chinensis in the A4 treatment remarkably increased by 171.05 and 97.42% compared to the control （P〈 0.05）. ALA had an obviously toxic effect on O. chinensis. Moreover, ALA caused the photoinactivation of AChE and GPx, which induced nerve transmission blocking and the capability to defend oxidation damage declining. Meanwhile, a high dose of ALA could activate GSTs, which caused a feedback inhibition of the insect to the phototoxic substance.展开更多
文摘东亚飞蝗Locusta migratoria manilensis(Meyen)是我国主要的农业害虫之一,已发现东亚飞蝗对某些农药产生了抗性,其抗性机制可能与谷胱甘肽硫转移酶(GST)代谢解毒相关。本研究利用特异性引物合成东亚飞蝗GST4个不同家族基因的双链RNA(dsRNA),将dsRNA注射到东亚飞蝗幼虫体内,采用Real time RT-PCR技术测定了干扰不同时间后目的基因mRNA的表达水平。结果表明,4个不同家族GST的沉默效应具有时间差异。来自delta家族的LmGSTd1和sigma家族的LmGSTs5基因在注射dsRNA后12h时mRNA量就已显著下降;而来自theta家族的LmGSTt1和unknown家族的LmGSTu1基因在注射24h后mRNA水平才呈现显著下降。本研究对后续东亚飞蝗GST功能及抗性机制研究提供了基础资料和依据,同时对其它昆虫RNA干扰研究具有一定的借鉴作用。
基金the National Natural Science Foundation of China(30570247)Study Abroad Foundation of Shanxi Province,Natural Science Foundation of Shanxi Province(2006011075)Youth Foundation of Shanxi Province,China(2007021030).
文摘Insecticidal activities and effects on three enzymic activities caused by 5-aminolevulinic acid （ALA） on Oxya chinensis were studied. Fourth-instar nymphs of O. chinensis were treated with different doses ofALA （A1,250 mM; A2, 450 mM; A3,750 mM; A4, 1 000 mM）. Mortality and the activities of acetylcholinesterase （ACHE）, glutathione S-transferase （GSTs）, and glutathione peroxidase （GPx） were determinated. The mortality of O. chinensis rose with an increasing dose of ALA. The mortality of high-dose treatments A3 and A4 reached 66.19 and 80.21%, respectively. The value of LD50 was 3.61 （3.29-3.93） mg·g^-1 body weight （95% confidence interval）. Biochemical studies showed that the activities of AChE and GPx in the A4 treatment declined by 51.53 and 42.82% in the female, and 42.65 and 43.85% in the male compared to the control, respectively, and the degree of decline reached a significant level at P 〈 0.05. Meanwhile, the GSTs activities of O. chinensis enhanced with increasing dose of ALA. The GSTs activities of female and male O. chinensis in the A4 treatment remarkably increased by 171.05 and 97.42% compared to the control （P〈 0.05）. ALA had an obviously toxic effect on O. chinensis. Moreover, ALA caused the photoinactivation of AChE and GPx, which induced nerve transmission blocking and the capability to defend oxidation damage declining. Meanwhile, a high dose of ALA could activate GSTs, which caused a feedback inhibition of the insect to the phototoxic substance.
