可口革囊星虫Phasolosma esculenta体腔液的抗菌活性研究

可口革囊星虫Phasolosma esculenta为我国特有的一种可食用海洋经济动物。本文以可口革囊星虫为研究对象,利用琼脂径向扩散、涂板计数等方法研究其体腔液中物质的抗菌活性以及理化特性。研究结果表明,可口革囊星虫体腔液中存在抗菌活性物质,并且该物质对金黄色葡萄球菌Staphylococcus aureus等3种革兰氏阳性细菌具有明显的抗菌效果,但对大肠杆菌Escherichia coli等3种革兰氏阴性细菌以及葡萄牙假丝酵母Candida lusitaniae抗菌效果不明显。结果还发现:(1)不同提取方式出现明显不同的抗菌效果,与体腔液上清液和2%乙酸提取体腔液所得提取物的抗菌效果相比,超声破碎处理提取物的抗菌效果最为明显。(2)理化特性研究发现该抗菌物质抗菌效力持久,抗冻融,并且在5~30 ℃范围内最适抗菌温度约为25 ℃;该物质不耐高温,60 ℃处理10 min后该物质的抗菌作用完全消失;此外,该物质的抗菌作用不依赖金属离子的存在。(3)超滤管过滤截留琼脂扩散结果表明该抗菌物质的分子量在100 kDa以上。

Antibacterial activity of the coelomic fluid from a marine worm,Phasolosma esculenta

Phasolosma esculenta is a peculiar edible marine economic species in China. In this study, the antimicrobial effect and physical and chemical characteristics of coelomic fluid extracted from Phasolosma esculenta was examined with agar diffusion and plate counting method. The result shows that this fluid is found to have an antibacterial activity against three G⁺ bacteria (Staphylococcus aureus, etc), but has no obvious antibacterial activity against three G^- bacteria (Escherichia coli, etc) and the yeast Candida lusitaniae. Results also show that: (1) Different extraction procedure shows different antibacterial activity. Three extraction procedures are compared: (a) the coelomic fluid without any treatment; (b) with ultra sonication and (c) mixed with 2% acetic acid. Pretreated with an ultra-sonication step, the extract has the best antibacterial effect. (2) The antibacterial activity of this component is effective up to 90 minutes and freezing-resistant. With its optimal temperature of 25 ℃, it shows an antibacterial effect within temperature ranging from 5 to 30 ℃. The fluid is inactivated with water bath treatment at 60 ℃ for 10 minutes. In addition, the antibacterial activity is independent from the metal ions. (3) Moreover, by separating fluid components based on molecular weights, it shows that the effective component is larger than 100 kDa.