一种噬菌体裂解酶的抗龋作用研究  

Anti-caries Effect of A Bacteriophage Lysin

作　　者：徐晶晶 陶庭亮[2] 李宇红[1] XU Jing-jing;TAO Ting-liang;LI Yu-hong(The State Key Laboratory Breeding Base of Basic Science of Stomatology and Key Laboratory of Oral Biomedicine Ministry of Education,School and Hospital of Stomatology,Wuhan University,Wuhan 430079,China;Department of Prosthodontics,Hefei Stomatology Hospital,Hefei 230001,China)

机构地区：[1]武汉大学口腔医学院口腔基础医学省部共建国家重点实验室培训基地和口腔生物医学教育部重点实验室,湖北武汉430079 [2]合肥市口腔医院修复科,安徽合肥230001

出　　处：《口腔医学研究》2018年第10期1052-1056,共5页Journal of Oral Science Research

基　　金：国家自然科学基金(编号:81670981)

摘　　要：目的:探讨噬菌体裂解酶ClyR对变异链球菌(Streptococcus mutans,S.mutans)和远缘链球菌(Streptococcus sobrinus,S.sobrinus)临床株的杀菌作用。方法:收集重度低龄儿童龋(severe early childhood caries,SECC)患者牙菌斑标本进行厌氧培养,通过菌落形态、生化鉴定、16SrDNA序列分析等方法对获得的临床株进行鉴定。通过细菌浊度A600的降低和最低杀菌浓度(minimum bactericidal concentration,MBC)评价ClyR的杀菌效果。透射电镜(transmission electron microscopy,TEM)初步探究ClyR的杀菌作用机制。结果:从分离得到的菌株中随机挑选10株S.mutans和10株S.sobrinus进行杀菌活性测试,50mg/L ClyR对8株S.mutans有明显杀菌作用,其MBC范围为125mg/L至>1000mg/L不等;对3株S.sobrinus有杀菌作用,其MBC范围为125~500mg/L不等。TEM观察结果表明ClyR可在细菌细胞壁上打孔,从而使细菌发生渗透性死亡。结论:ClyR对S.mutans和S.sobrinus均有较强的杀菌作用,但对S.mutans杀菌作用较S.sobrinus强,或许可以作为一种防龋药物应用于临床。Objective:To evaluate the bactericidal activity of a bacteriophage lysin ClyR on the clinical strains of streptococcus mutans(S.mutans)and streptococcus sobrinus(S.sobrinus).Methods:Dental plaques of children with severe early childhood caries(SECC)were obtained and cultured for S.mutans and S.sobrinus isolation.Morphology observation,biochemistry identification,and a 16S rDNA sequencing analysis were used to identify all clinical isolates.The bactericidal activity of ClyR on S.mutans and S.sobrinus isolates were determined by turbidity decrease assay and minimum bactericidal concentration(MBC)assay.Transmission electron microscopy(TEM)was used to visualize the effects of ClyR on the bacterial cell wall.Results:10 S.mutans and 10 S.sobrinus were randomly selected from the isolates to test the susceptibility to ClyR.8 of 10 S.mutans isolates and 3 of 10 S.sobrinus isolates were susceptible to ClyR,with MBC ranging from 125 mg/L to>1000 mg/L and 125 mg/L to 500 mg/L,respectively.TEM showed that ClyR could degrade the bacteria cell wall,which resulted the osmotic death.Conclusion:ClyR exhibits strong lytic activity against both S.mutans and S.sobrinus isolates,but the S.mutans is better than S.sobrinus,which represents a preventative or therapeutic agents against dental caries.

关 键 词：变异链球菌 远缘链球菌 临床株 噬菌体裂解酶 龋病 

分 类 号：R781.1[医药卫生—口腔医学]