变形链球菌和远缘链球菌耐氟菌株超微结构观察

目的：探讨变形链球菌和远缘链球菌耐氟突变后，其超微结构变化及氟化物对细菌结构的影响。方法：将变形链球菌和远缘链球菌分为3组：A为正常对照组；B为加氟孵育组；C为耐氟菌株组。透射电镜观察3组细菌的超微结构。结果：与正常亲代菌株相比，加氟孵育后的菌株及耐氟菌株菌体出现不同程度超微结构改变，包括胞浆电子密度减低，细胞肿胀，内容物外溢，远缘链球菌链状结构消失等。结论：变形链球菌和远缘链球菌与氟共同孵育及耐氟突变后，其超微结构发生了改变，表现为自溶活动及解链活动增强。

Ultrastructural changes in Streptococcus mutans and Streptococcus sobrinus after their fluoride-resistant mutation

AIM:To observe the ultrastructure changes of Streptococcus mutans and Streptococcus sobrinus after their fluoride-resistant mutation and to find out the effect of fluoride on the structure of Streptococci. METHODS:The Mutans Streptococci were divided into three groups: Group A, control group which contained 4 strains of parent wild-type Streptococci; Group B, fluoride-treated group which contained Streptococcus mutans Ingbritt and Streptococcus sobrinus 6715; Group C, fluoride-resistant group which contained 4 strains of fluoride-resistant Streptococci. The bacteria of three groups were observed under transmission electron microscope. RESULTS:Compared with the bacteria of control group, the F-treated specimen and the fluoride-resistant mutants appeared alterations in ultrastructure,such as less electron-dense areas in cytoplasm, cell swelling, leakage of intracellular materials, de-chaining in Streptococcus sobrinus, etc. CONCLUSION: F-resistant and F-treated S.mutans and S.sobrinus showed altered ultrastructure compared with the control group. Their de-chaining and autolysis activity had enhanced.