变形链球菌表面蛋白A区遗传多态性的研究

目的:探讨变形链球菌表面蛋白A区遗传多态性与其粘附性能的关系。方法:分别选取本实验室前期工作所获得的粘附能力较强和较弱的血清c型变形链球菌临床分离株，提取全菌DNA，经PCR扩增表面蛋白A区编码基因spaP-a后，用限制性内切酶Hae班进行限制性片段长度多态性分析。结果:经Hae ]II酶切后，两组血清c型变形链球菌均出现了4种基因型，且4种基因型在两组菌株的构成情况不同。结论:血清c型变形链球菌临床分离的 spaP-a具有遗传多态性，粘附能力较强的菌株比粘附能力较弱的菌株具有更明显的异质性。

A Study on the Genetic Diversity within A-region of Surface Protein of Streptococcus mutans

Objective:The purpose of this study was to investigate the relationship between genetic diversity within A-region of surface protein of Streptococcus mutans (serotype c) and their binding abilities. Methods: The clinical isolates of 5. mutans (serotype c) included two groups with different binding abilities (cpm > 2000, cpm < 1000) , which were derived from former work in our experimental lab. The bacterial DNA was extracted, and the spaP-a (473 - 1571 bp) was amplified using polymerase chain reaction (PCR). Genetic diversity of spaP-a was assessed by using restriction fragment-length polymorphism (RFLP) with restriction endo-nuclease Hae. Results: Four different patterns of the spaP-a PCR-RFLP among strains were revealed when digested with Hae M . The proportions of four genotypes of strains with different binding abilities were different ( P < 0.05) . Conclusion: The genetic diversity exists within the spaP-a (473 - 1571 bp) of the clinical isolates of S. mutans (serotype C) . The diversity of strains with higher binding ability was more apparent than those with lower one.