增效磷对昆虫体内还原型谷胱甘肽及谷胱甘肽转移酶的影响

THE EFFECT OF SV_1(O,O-DIETHYL-O-PHENYL-THIOPHOSPHATE ON THE GLUTATHIONE CONTENT AND GLUTATHIONE-STRANSFERASE ACTIVITY IN LARVAE OF HELIOTHIS AND CHILO SPECIES

增效磷(SV_1)对敌百虫在棉铃虫、粘虫、二化螟及小白鼠4种测试动物上均表现增效作用,增效比值为2～3.本试验用增效磷进行昆虫体壁或小白鼠口投处理,体内谷胱甘肽(GSH)含量在5小时后明显下降。离体状态下,二化螟6龄幼虫中肠谷胱甘肽转移酶(GST)被增效磷抑制,当增效磷浓度为5.1×10^(-8)molL^(-1)时,抑制率可达68.3%。体内抑制试验表明,用 SV_1预处理5小时后,GST活性首先增大,以后慢慢降低,24小时后,又被抑制43.0%。初步认为,SV_1影响参与降解敌百虫的 GSH—GST 体系的作用,也是对敌百虫产生增效作用的一个机制。

An evaluation of the synergism of SV1（O,O-diethyl-O-phenyl-thiophosphate）totrichlorfon on the cotton bollworm（Heliothis armigera H（?）b）,the striped rice borer[Chilosuppressalis（Walker）],the oriental armyworm[Mythimna separata（Walker）]and the micewas made in the laboratory by means of bioassaies and biochemical analyses.The results ofbioassaies revealed that SV1 could effectively increase the contact toxicity of trichlorfon tothe larvae of these test insects and also the stomach toxicity to mice.Biochemical analyses alsoshowed that the glutathione level was reduced and the glutathione-S-transferase activity wasdecreased by the SV1 treatment.The GSH contents were reduced after treatment withSV1 topically at the dosage of 150μg/larvae,31.2/μg/larvae and 2.5μg/larvae on cot-ton bollworms,oriental armyworms and striped rice borers.The decreasing rates were31.9%,26.5%,and 35.7%,respectively,after 5 hours,and 38.8% in mice liver by oraltreatment at the rate of 1.4mg/g body wt.of mice.In vitro test,the inhibition rate forSV1(at the concentration or 5.1x10-8mol L-1)to GST in the midgut of the striped rice borerswas 68.3%,but in vivo test,it was found that within 10 hours after topical treatment withSV1（2.5μg/larvae）,the GST activity was higher than that of the control,and then de-clined gradually.After 24 hours,only 57.0% of original activity was remained,the inhibi-tion rate being 43.0%.