苦参碱对小菜蛾幼虫毒力测定及其对害虫体内2种酶活性的影响

采用生物测定和酶活力测定方法，研究苦参碱对小菜蛾Plutella xylostella L．的胃毒活性及其对幼虫体内谷胱甘肽-S-转移酶、乙酰胆碱酯酶活性的影响。试验结果表明：苦参碱对小菜蛾幼虫具有一定的胃毒作用。2mg／mL苦参碱处理叶片饲喂小菜蛾幼虫12h校正死亡率为37．93％，72h后小菜蛾幼虫的校正死亡率为95．83％。不同质量浓度苦参碱处理小菜蛾幼虫后，幼虫体内的谷胱甘肽-S-转移酶（GSTs）和乙酰胆碱酯酶（AchE）活力与对照相比均产生波动。经125×10 -3mg／mL苦参碱处理4h，小菜蛾体内GSTs活力最高，为1610．72U／（mg·min）。经125×10mg／mL苦参碱处理16h，小菜蛾体内的AChE酶活力最高，为10．63U／（mg·min）。各处理24h，小菜蛾体内GSTs活力和AChE酶活力均有明显降低。说明苦参碱对小菜蛾幼虫体内谷胱甘肽-S-转移酶活力和乙酰胆碱酯酶活力有一定的影响。     

植物次生物质对棉铃虫谷胱甘肽S-转移酶和乙酰胆碱酯酶的影响

分别用含０．０１％的芸香甙,槲皮素２－十三烷酮的人工饲料连续饲养棉铃虫Ｈｅｌｉ－ｃｏｖｅｒｐａａｒｍｉｇｅｒａＨｕｂｎｅｒ１～７代,测定不同处理的棉铃虫种各谷胱甘肽Ｓ－转移酶（ＧＳＴ）和乙酰胆碱酯酶（ＡＣｈＥ）的活性变化以及幼虫对杀虫剂的反应,以单独人工饲料养的各种作对照,芸香甙Ｆ１代对甲基硫磷的耐药性提高３倍,槲皮素Ｆ１,Ｆ２代和２－十三烷酮Ｆ１代对甲基对硫磷的耐药性有所提高,对灭多威和溴氰菊酯     

不同地理种群棉蚜三种关键性酶活差异及其与抗性相关性

【目的】研究新疆不同地理种群棉蚜3种酶的活性及抗药性的差异。【方法】测定新疆库尔勒、五家渠、石河子、奎屯、哈密地区棉蚜和实验室敏感种群羧酸酯酶、谷胱甘肽-S-转移酶、乙酰胆碱酯酶活性,并分析3种酶活性与吡虫啉抗性之间的关系。【结果】库尔勒、五家渠、石河子、奎屯和哈密地区乙酰胆碱酯酶和谷胱甘肽-S-转移酶的比活力比值分别为4.2、2.7、2.3、2.5、2.1倍和2.3、1.5、1.3、2.5、2.1倍,差异显著（P<0.05）;羧酸酯酶比活力比值为6.5、4.2、3.4、2.7、1.2倍,除哈密地区相对接近外,其余地区均明显高于1.0,差异显著（P<0.05）,2种棉蚜关键解毒酶和1种神经传导关键性酶与抗药性之间存在一定相关性。【结论】各地理种群棉蚜3种酶活性均显著高于敏感种群（P<0.05）,且彼此之间存在差异性,羧酸酯酶在棉蚜感受到吡虫啉杀虫剂胁迫时极有可能起到重要作用。     

蛇床子素对小菜蛾幼虫的胃毒作用及对虫体内两种酶活性的影响

采用生物测定和酶活力测定方法,研究了蛇床子素对敏感品系小菜蛾Plutella xylostellaL.的胃毒作用及其对小菜蛾幼虫体内谷胱甘肽-S-转移酶、乙酰胆碱酯酶活性的影响。结果表明：蛇床子素对小菜蛾幼虫具有一定的胃毒作用。2 mg/mL的蛇床子素处理萝卜苗叶片后饲喂小菜蛾幼虫12 h校正死亡率为37%,72 h时后小菜蛾幼虫的校正死亡率为93%。处理24 h时,LC50为1 521.25 mg/mL,处理48 h时,LC50为865.93 mg/mL。处理72 h时,LC50为515.5 mg/mL。不同浓度蛇床子素和不同时间处理小菜蛾幼虫后,幼虫体内的谷胱甘肽-S-转移酶和乙酰胆碱酯酶活力均产生了消长变化。经125×10-3mg/mL蛇床子素处理16 h时,小菜蛾体内的GSTs活力最高为209.15 U.mg-1prot.min-1。经125×10-3mg/mL蛇床子素处理4 h时,小菜蛾体内的AchE酶活力最高,为0.648 1 U.mg-1prot.min-1。各处理在24 h时,小菜蛾体内的GSTs活力和AchE酶活力均有明显的降低。说明蛇床子素对小菜蛾幼虫体内的谷胱甘肽-S-转移酶和乙酰胆碱酯酶活力重要的影响。     

Cry8E亚致死浓度对马铃薯甲虫解毒酶和保护酶的影响

苏云金芽胞杆菌Cry8E杀虫晶体蛋白对马铃薯甲虫具有中等毒性,用亚致死剂量9和7μg/m L的Cry8E分别饲喂2、3和4龄的马铃薯甲虫幼虫,然后测定羧酸酯酶(Car E)、乙酰胆碱酯酶(ACh E)、谷胱甘肽-S-转移酶(GST)和过氧化氢酶(CAT)的酶活性。β-羧酸酯酶的活性随Cry8E浓度的升高明显提高,随龄期增长活性降低,酶活性在浓度间和龄期间差异都极显著。谷胱甘肽-S-转移酶活性下降,2龄幼虫体内的乙酰胆碱酯酶的活性明显升高,并且随龄期变化差异显著(P0.01)。3龄幼虫体内的CAT酶活性随Cry8E浓度的增加而显著升高(P0.01)。本研究阐明了Cry8E对马铃薯甲虫解毒酶和保护酶活性的影响,为理论研究奠定基础。     

Phytotoxicity of solanapyrones A and B produced by the chickpea pathogen Ascochyta rabiei(Pass.) Labr. and the apparent metabolism of solanapyrone A by chickpea tissues

When chickpea shoots were placed in solanapyrone A, the compound could not be recovered from the plant and symptoms developed. These consisted of loss of turgor, shrivelling and breakage of stems and flame-shaped, chlorotic zones in leaflets. In similar experiments with solanapyrone B, only 9.4% (22 μ g) of the compound taken up was recovered and stems remained turgid but their leaflets became twisted and chlorotic and some abscized.Cells isolated from leaflets of 12 chickpea cultivars differed by up to five-fold in their sensitivity to solanapyrone A and this compound was 2.6–12.6 times more toxic than solanapyrone B, depending on cultivar.Glutathione reacted with solanapyrone A in vitro reducing its toxicity in a cell assay and forming a conjugate. Measurement of reduced glutathione concentration and glutathione-S-transferase (GST) activity among cultivars showed that the differences of their means were highly significant and both were negatively and significantly correlated with their sensitivity to solanapyrone A. Treatment of shoots with solanapyrone A enhanced total, reduced and oxidized glutathione content as well as GST activity 1.26-, 1.23-, 1.50- and 1.94-fold, respectively. Similarly, treatment of shoots with the safener, dichlormid, also raised total, oxidized and reduced glutathione levels and GST activity 1.42-, 1.07-, 1.43-, 1.42-fold, respectively. Cells isolated from shoots treated with dichlormid at 150 and 300 μ g per shoot were 2.45 and 2.66 times less sensitive to solanapyrone A, with LD₅₀values of 71.5 and 77.8 μ g ml⁻¹, respectively, as compared to 29.2 μ g ml⁻¹for controls.     

Developmental expression of glutathione-S-transferase in maize and its possible connection with herbicide tolerance

Summary Crop improvement for tolerance to specific herbicides is an important breeding target, since molecules performing well with regard to environmental safety are frequently not completely selective for crops. The glutathione (GSH)/glutathione-S-transferase (GST) system is a general mechanism of detoxification that in higher plants may confer tolerance to some herbicides. GSH level and GST activity were measured in different maize inbred lines, in the absence or in the presence of EPTC (a thiocarbamate) and of Alachlor (a chloroacetanilide); a wide genetic variability was observed for these parameters, which appear to be involved in plant tolerance to herbicides. Isozyme analysis was performed on roots, leaves, scutellum, pollen, coleoptile, mesocotyl of the same inbreds: it revealed the presence of many GST forms in maize, showing high polymorphism; they are controlled by at least five genes, the expression of which is developmentally regulated in the different tissues analyzed.     

紫杆柽柳谷胱甘肽硫转移酶基因的克隆及功能鉴定

根据GenBank已公布的植物谷胱甘肽硫转移酶基因EST序列，设计引物利用3’和5’RACE方法，获得紫杆柽柳GST基因(TaGST)全长cDNA序列，全长为1175 bp，开放读码区672 bp, 编码224个氨基酸。其所编码的蛋白与大豆的GST10同源性最高为48%。利用pET-28a（+）构建了紫杆柽柳GST基因的原核表达载体，转入BL21大肠杆菌进行了原核表达。诱导表达蛋白的SDS-PAGE检测表明, 所表达的蛋白分子量约为26 kD，与预测的分子量大小一致。初步的酶学活性的检测表明所克隆的基因编码的肽段具有催化GST蛋白通用底物CDNB和GSH反应的活性。     

玉米全基因组谷胱苷肽-S-转移酶基因家族的分析

谷胱苷肽转移酶(glutathione-S-transferase,GST)是植物生长发育过程中一类多功能酶,在植物的初级代谢和次级代谢以及调控植物的逆境胁迫和细胞信号转导等过程中具有重要作用。根据GST蛋白序列构建的隐马尔可夫模型(hidden markov model,HMM),鉴定玉米全基因组GST基因,并对GST基因数量、类型、染色体定位和进化关系进行分析。结果表明,玉米全基因组中共含有37个GST基因,在10条染色体上呈非随机分布,具有U型、F型和Z型3个亚族。与水稻比较,玉米未发现T亚族。该研究结果对深入了解GST基因家族的分子进化以及GST基因的克隆和功能验证提供了重要参考依据。     

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

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。