苏云金芽孢杆菌的概况及其研究进展

苏云金芽孢杆菌(Bacillus thuringiensis,Bt)杀虫剂是对人和环境友好的安全型细菌杀虫剂。目前Bt杀虫剂已被广泛应用,但因使用剂量较大,导致防治害虫时费用过高。若在生物防治中使用超高效的细菌杀虫剂,就可降低其使用剂量。Bt 00-50-5菌株是从美国引进的高效杀虫菌株,其晶体蛋白的特征分析尚未完成,其毒素的作用机理研究也未进行。本项目即将开展如下研究:(1)先用具有特异性杀虫功能的Bt 00-50-5菌株进行发酵,继续完成对防治中国害虫防治效果的评价;再分析细菌的编码杀虫毒素基因和毒素的生化特征;然后混合荧光标记毒素和中肠细胞,加入昆虫中肠蛋白酶(或单独加入氨肽酶、碱性磷酸酶、ATP酶、枯草杆菌蛋白酶、钠或钾离子代之)反应,用荧光显微镜观察细胞变化;最后阐明杀虫毒素对靶标细胞作用机制。(2)通过研究毒素分子与受体分子的作用关系,拟在分子水平上阐明毒素的作用机制。

A Profile of Bacillus thuringiensis and Research Progress on It

The Bacillus thuringiensis(Bt) pesticide is a friendly safety bacterial insecticide to human and environment.Update,the Bt pesticide has been widely used in the world,but its dosage used in the pest control is relatively high,resulting in comparatively high cost in the application.It could reduce the dosage used and the cost in the application if a bacterial insecticide with extremely high activity is used in the pest control.Bt 00-50-5 strain with a high insecticidal activity was imported from the United States of America,but the analysis of the characterization relating its crystal protein has uncompleted,and the mechanism of mode of action about its toxin has not been studied yet.The present research plan is as follows:(1) At the first doing the fermentation using a Bt 00-50-5 strain with a special insecticidal function and continuing the evaluation its efficacies against Chinese important pests;then carrying out the analysis of the gene encoding the insecticidal toxin and the biochemical characterization of the toxin;afterwards observing the cell variations with fluorescence microscope after mixing the fluorescence labeling toxin and the target middgut cells(receptor),adding insect midgut protease(or individual adding aminopeptidase,alkaline phosphotase,ATPase or subtilisin,Na+ or K+ ions instead of it) for reaction;and finally estimating the toxin amount in the cells by the Western Blot.The mechanism of action about the insecticidal toxin against the target cell will be validated.(2) The mechanism of action about the insecticidal toxin will be validated at the molecular level by study the relationship of the toxin molecule and its receptor molecules.