家蝇变形期抗菌蛋白的提取

目的:分离纯化家蝇变形期体内抗菌蛋白并分析其抑菌作用。方法:对家蝇（Ｍusca domestica）5日龄幼虫进行针刺诱导，并于24h后挑取变形后的蛹，通过研磨、调酸、加热提取蛹体内的耐热水溶总蛋白，经过两步CM sepharose F.F.离子交换层析分离，以金黄色葡萄球菌作指示菌，检测其抑菌活性，并用SDS PAGE不连续电泳检测蛋白质的分子量。结果:经两步离子交换分离后，得到一种对金黄色葡萄球菌具有较强抑菌活性的蛋白，经SDS PAGE检测为单一条带，其分子量为43kDa。结论:家蝇处于变形期时，经过诱导后体内能产生一种抑菌活力较强的蛋白质。

Activity Study on Antibacterial proteins Isolated

Objective: To research the activity of antibacterial proteins isolated from Musca domestica during larvae-pupae metamorphosis. Methods: The 5-day-old larvae of Musca domestica were injured with a needle. 24h later, the larvae which had changed into pupae were selected. The antibacterial protein was isolated by a four-step protocol including grinding, heating, CM-sepharose F.F. cation-exchange chromatography and another CM-sepharose F.F. chromatography. Antibacterial activities of samples were tested by an ultrasensitive radial diffusion assay using Staphylococcus aureus as the indicator organism. The molecular weight of the isolated protein was determined by SDS-PAGE. Results: The molecular weight of this isolated protein was 43kDa, and its antibacterial activity was strong. Conclusions: A kind of protein with strong antibacterial activity can be produced in the Musca domestica during larvae-pupae metamorphosis.