苏云金芽孢杆菌对新秀丽小杆线虫的作用

新秀丽小杆线虫是一种模式生物，能够在室内培养。本研究采用大肠杆菌饲养，获得大量虫源，通过观察该线虫对不同Bt菌株产生毒力反应的情况，筛选含有毒力的Bt菌株。经筛选获得6个菌株的伴孢晶体对新秀丽小杆线虫进行毒性比较，野生菌株Bt-010杀虫快速而持久，毒力强，作用时间大约在36h左右，测得其理想的LC50为0.498µg/ ml。初步纯化其毒性蛋白，发现其主要作用成分是大小为25 – 35 kD的蛋白。DNA Ladder检测发现在这个毒性蛋白不象化学农药一样对线虫的DNA造成损伤。

Toxicity of Bacillus thuringiensis to Caenorhabditis elegans

Caenorhabditis elegance is one of the model organisms that could be raised with Escherichia coli in lab. Crystal proteins from B. thuringiensis are pore-forming toxins used as insecticides around the world . A collection of Bt strains were screened for toxic activity against the nematodes .Six strains were identified with significant toxicity to the adult nematodes in vitro. By assaying their toxicity on free-living nematodes ， within 36 hours ， the LC50 of the nematicidal toxins achieved 0.498 µg/ml . It’s concluded that Bt crystal proteins have potential in controlling nematodes . Toxic proteins were purified crudely by sulfate and the sizes were estimated by comparison with protein standards. DNA ladder survey showed that the toxic protein did not damage the DNA of nematodes as chemical pesticides.