Detection of Bacillus cereus heat-stable toxin

从引起食物中毒的食物中分离到的蜡样芽孢杆菌产生的热稳定毒素可引起HEp-2和肠407培养细胞的形态学改变。在含大米和牛奶的培养基中产毒量最高。虽然在含有硫酸铵和酵母提取物的半合成培养基中，tpoxin的产量很低，但通过向培养基中添加0.5%葡萄糖，产量增加。在含0.5%葡萄糖的培养基中，研究了通气量与产毒量的关系。通过剧烈振荡通气，在培养的第4小时观察到毒素产生，并且在培养的第8小时检测到最大产生。当时未检测到孢子。24小时即可检测到产孢，不振荡培养48小时产孢率很低，但产毒程度与振荡培养相同。采用硫酸铵盐析、正丁醇萃取和C_柱反相层析等方法对毒素进行纯化<18>。虽然毒素没有完全纯化，但毒素似乎含有蛋白质。

Bacillus cereus strain isolated from causative food of food poisoning produced heat stable toxin causing morphological changes in culture cells of HEp-2 and Intestine 407. The toxin production was optium in rice and milk containing media. Although the tpoxin production was low in a semi-synthetic medium containing ammonium sulfate and yeast extract, the production increased by the addition of 0.5% glucose to the medium. Relationship between toxin production and aeration was investigated in the medium containing 0.5%glucose. With aeration by vigorous shaking, the toxin production was observed at 4th hr of cultivation and a maximal production was detected at 8th hr of cultivation. The spore was not detected at that time. The spore was detected at 24 hr. Without shaking, the rate of sporulation was very low even at 48hr though the extent of the toxin production was the same as that of the shaking culture. For purification of the toxin, salt-out with ammonium sulfate, n-butanol extraction and reversed-phase chromatography with C_<18> column were effective. Although the toxin was not purified completely, the toxin seems to contain a protein.