变形链球菌牙面粘附唾液受体的筛选和纯化

Separation and Selection of Salivary Adhesion Receptors\;of Streptococcus mutans to Tooth Surface

目的:筛选和纯化变形链球菌血清型c(简称变链)的牙面粘附唾液受体。方法:用全唾液包被羟基磷灰石形成实验性获得性膜(SAP),后用1mol/LNaCl和0.5mol/L磷酸盐缓冲液分步洗脱,再用SephadexG75分子筛层析和DEAE-SephadexA25离子交换层析对SAP组分进行分离纯化,用细菌粘附实验和细菌粘附竞争抑制实验筛选受体,经聚丙烯酰胺凝胶电泳、等电聚焦电泳、淀粉酶活性测定等实验鉴定。结果:IgA降解片段、淀粉酶和分子量为13kD的蛋白是变链的牙面粘附唾液受体,其中IgA降解片段和分子量为13kD的蛋白为隐匿受体,淀粉酶组份在变链粘附中具双重作用。

Objective:To select and purify salivary receptors of Streptococcus mutans from experimental salivary acquired pellicle.Methods: Experimental salivary acquired pellicle (SAP) was performed by coating hydroxyapatite (HA) with whole saliva. Then SAP was washed from HA by 1 mol/L NaCl and 0 5 mol/L phosphate buffer sequentially. The proteins were further separated by chromatography of Sephadex G75 and DEAE Sephadex A25. Receptors of Streptococcus mutans were selected by bacterial adhesion test and competitive inhibition adhesion test. Identification was performed by PAGE, SDS PAGE,IP PAGE and detection of amylase activity and inmunodifusion test. Results: IgA degraded fragments, a protein of 13 kD and amylases were the receptors of S.mutans. The first two only promote the adhesion but the amylases can both promote and inhibit S.mutans adhesion.Conclusion: The adhesion of S.mutans to tooth surface is a result of interaction between adhesins of S.mutans and multiple salivary receptors.\;