菲律宾蛤仔凝集素抑菌机制的研究

Antibacterial mechanism of short-neck clam Ruditapes philippinarum lectin(MCL-T)

通过分析菲律宾蛤仔Ruditapes philippinarum凝集素(MCL-T)对细菌的呼吸代谢及细菌中总DNA、总RNA和可溶性蛋白合成的影响,以及MCL-T与金黄色葡萄球菌膜蛋白(OMP)的相互作用及其核酸酶(RNase)活性,研究了MCL-T的抑菌机制。结果表明:MCL-T具有抑制金黄色葡萄球菌Staphylococcus aureus和枯草芽孢杆菌Bacillus subtilis代谢过程中的磷酸戊糖途径(HMP);MCL-T与金黄色葡萄球菌或枯草芽孢杆菌共同培养时,随着MCL-T质量浓度的增加,金黄色葡萄球菌或枯草芽孢杆菌中的总DNA、总RNA和可溶性蛋白含量均呈下降趋势;固相吸附测试表明,MCL-T可与金黄色葡萄球菌膜蛋白结合,两者的结合具有浓度依赖关系,该结合位点受N-乙酰-D-半乳糖酰胺(N-acetyl-D-galactosamine,GalNAc)及猪胃黏蛋白(Mucin from porcine stomach,PSM)的抑制,MCL-T具有RNase活性。研究表明,MCL-T通过抑制细菌的呼吸代谢及细菌中总DNA、总RNA和可溶性蛋白来发挥抑菌作用,同时其抑菌活性还与凝集素的OMP结合结构域和RNase活性结构域相关。

The effects of short-neck clam Ruditapes philippinarum lectin（ MCL-T） on respiration, and synthesis of total DNA, total RNA and soluble proteins in bacteria Staphylococcus aureus and Bacillus subtilis, and reaction of MCL-T with out membrane proteins （ OMP） of S. aureus and RNase activity of S. aureus were studied by solid phase assay to elucidate antibacterial mechanism of MCL-T. The MCL-T was shown to inhibit pentose phosphate pathway （ HMP） in respiratory metabolism of the bacteria. The contents of total DNA, total RNA and soluble pro-teins were decreased in both bacteria incubated with MCL-T with increase in concentrations of MCL-T. The solid phase assay revealed that MCL-T binding to out membrane proteins （ OMP） was concentration-dependent and in-hibited by PSM or GalNAc with RNase activity. The findings indicated that MCL-T inhibited the growth of the two bacteria by respiration inhibition, and the antibacterial activities of MCL-T were related to its domains of binding to OMP and to RNase activity.