苏云金杆菌营养期杀虫蛋白的研究

营养期杀虫蛋白 (vegetativeinsecticidalproteins ,VIPs)是苏云金杆菌 (Bacillusthuringiensis,Bt)在对数生长中期分泌的一类新型杀虫毒蛋白。VIPs主要分为VIP1、VIP2和VIP3三种。VIP1和VIP2构成二元毒素 ,对鞘翅目叶甲科的昆虫具有杀虫特异性 ;而VIP3对鳞翅目昆虫具有较广谱的杀虫活性。VIP1和VIP2的杀虫作用机理还不清楚 ;VIP3通过诱发细胞凋亡 ,最终导致昆虫死亡 ,这种作用机理与Bt杀虫晶体蛋白的作用机理完全不同 ,这为筛选新的杀虫活性物质提供了新的思路。vip基因现已被应用于转基因杀虫植物的构建 ,得到高效抗虫的多价转基因玉米。此外 ,VIPs嵌合蛋白的构建、vip及其融合基因导入其它许多宿主微生物等方面的研究也具有诱人的潜在应用前景。

Research on Vegetative Insecticidal Proteins of Bacillus thuringiensis

Novel vegetative insecticidal proteins (VIPs) are secreted outside the cell during Bacillus thuringiensis(Bt) mid-logarithmic growth. Bt harbors a variety of VIPs, including VIP1,VIP2 and VIP3. VIP1 and VIP2 are components of a binary toxin which is specifically active against diabrotica insect larvae. However, the mechanism of this specific activity isn't known. VIP3 shows activity against many lepidopteran insect larvae. It exerts insecticidal properties on susceptible insect cells by triggering an apoptotic-type of programmed cell death(PCD). This mechanism is different from that of insecticidal crystal proteins(ICPs), and can be used to screen for novel chemical ligands. Recently vip genes have been applied in the construcion of transgenic plants which are resistant to insects, and maize plants active against insects were obtained. The potential prospect on chimeric toxins derived from VIPs and host microorganisms transformed with vip or its hybrid genes was discussed.