frtR基因对变异链球菌产酸及脱矿能力影响的研究  

frtR Gene Affects Acid Production and Demineralization Ability of Streptococcus mutans

作　　者：敬美玲 卢淼 郑婷 龚涛[1] 李雨庆[1] 周学东[1] JING Mei-ling;LU Miao;ZHENG Ting;GONG Tao;LI Yu-qing;ZHOU Xue-dong(State Key Laboratory of Oral Diseases,National Clinical Research Center for Oral Diseases,West China Hospital of Stomatology,Sichuan University,Chengdu 610041,China)

机构地区：[1]口腔疾病研究国家重点实验室,国家口腔疾病临床医学研究中心,四川大学华西口腔医院,成都610041

出　　处：《四川大学学报（医学版）》2022年第2期263-267,共5页Journal of Sichuan University(Medical Sciences)

基　　金：国家自然科学基金面上项目(No.31870065、No.32170046)资助。

摘　　要：目的研究TetR家族frtR基因对变异链球菌产酸能力和诱导牙体脱矿能力的影响。方法检测frtR基因框内缺失株(ΔfrtR)及回复株(ΔfrtR/pDL278-frtR)的生长情况;通过共聚焦激光扫描显微镜观察菌株的生物膜结构,并用蒽酮-硫酸法定量检测生物膜中的水不溶性胞外多糖(extracellular polysaccharide,EPS);通过糖酵解pH drop实验检测菌株的产酸能力;通过横断显微放射技术(transverse micro radiography,TMR)检测菌株诱导牛牙脱矿的能力。结果菌株生长曲线结果表明frtR基因对变异链球菌的生长无明显影响;共聚焦激光扫描显微镜观察结果显示frtR基因对变异链球菌生物膜形成无明显影响,硫酸-蒽酮法检测发现frtR基因对变异链球菌EPS合成亦无明显影响;糖酵解pH drop实验结果表明,当蔗糖为唯一碳源时,敲除frtR基因延缓了变异链球菌的产酸速率;TMR实验结果表明,敲除frtR基因降低了变异链球菌在牛牙表面诱导形成的脱矿深度和脱矿量。结论frtR基因缺失会减弱变异链球菌的产酸能力及诱导牙体组织脱矿能力。Objective To study the effect of the frtR gene of TetR family on the acid production ability of Streptococcus mutans(S.mutans)and the bacteria’s ability to induce tooth demineralization.Methods The growth of two strains of S.mutans UA159,ΔfrtR,the frtR gene in-frame deletion strain,andΔfrtR/pDL278-frtR,the complement strain,was examined.The structure of biofilm was observed by laser scanning confocal microscopy(LSCM).The quantitative determination of water-insoluble extracellular polysaccharide(EPS)in the bacterial biofilms was done by anthrone-sulfuric acid method.The acid production capacity of S.mutans was measured by glycolytic pH drop.The demineralization-inducing ability of the strains on bovine teeth was determined by transverse microradiography(TMR).Results The growth curves of the strains showed that frtR did not affect the growth of S.mutans.According to the findings of LSCM observation,frtR did not affect the biofilm formation.According to the findings of the anthrone-sulfuric acid method,frtR did not have any significant impact on the EPS synthesis of S.mutans.The results of the glycolytic pH drop assay showed that the deletion of frtR delayed the rate of acid production by S.mutans when sucrose was the only carbon source.In addition,according to the TMR results,knocking out frtR reduced the depth and amount of demineralization induced by S.mutans on the surface of bovine teeth.Conclusion The deletion of frtR can weaken the acid production ability and the demineralization ability of S.mutans.

关 键 词：变异链球菌 TetR家族 产酸 磷酸转移酶系统 

分 类 号：R781.1[医药卫生—口腔医学]