Yang De-qin, Liu Tian-jia, Zhuang Heng, Qi Qing-guo, Li Song, Liu Jian-guo
Department of Operative Dentistry and Endodontics, Affiliated Hospital for Stomatology of Zunyi Medical College, Zunyi Guizhou 563003, China.
Zhonghua Kou Qiang Yi Xue Za Zhi. 2006 Jan;41(1):29-32.
To study the genetic diversity of F-ATPase alpha subunit gene uncA derived from Streptococcus mutans (S. mutans) clinical isolates and to investigate the relationship between the genetic diversity of acidurance factor and S. mutans aciduric ability, also and the cariogenicity.
Sixty-four S. mutans strains derived from 34 caries-active individuals and 30 caries-free individuals, including 18 strains displaying high acid tolerance and 20 strains displaying low acid tolerance. Gene uncA was amplified with specific primers from S. mutans genomic DNA, then the PCR products were analyzed by RFLP and sequenced.
Two genotypes A and B of PCR-RFLP were revealed when digested with Hph I. Mbo II also produced two different pattern C and D. The distributions of A and B genotype strains with different caries-sensitivity groups were different (P < 0.05), and the proportion of A genotype strains from caries-activity group was higher than that from caries-free one. The distributions of C and D genotype strains with different acidurance strains were different (P < 0.05), and the proportion of C genotype strains from high acid tolerance group was higher than that from low acid tolerance group. These amplified uncA genes from different group were sequenced and there existed variation of Hph I and Mbo II recognized sites.
This study indicates that uncA gene of S. mutans F-ATPase obviously displayed genetic diversity. The different Hph I-RFLP and Mbo II-RFLP genotypes could be related to the cariogenicity and acid tolerance of S. mutans strains.
研究变形链球菌临床分离株F-ATP酶α亚基基因uncA的遗传多样性，探讨耐酸因子遗传多样性与变形链球菌耐酸能力及致龋性之间的关系。
从34名龋活跃个体和30名无龋个体中分离出64株变形链球菌，其中包括18株高耐酸菌株和20株低耐酸菌株。用特异性引物从变形链球菌基因组DNA中扩增uncA基因，然后对PCR产物进行RFLP分析和测序。
用Hph I酶切时，PCR-RFLP显示出两种基因型A和B。Mbo II酶切也产生两种不同的模式C和D。不同龋敏感性组的A和B基因型菌株分布不同（P<0.05），龋活跃组的A基因型菌株比例高于无龋组。不同耐酸菌株的C和D基因型菌株分布不同（P<0.05），高耐酸组的C基因型菌株比例高于低耐酸组。对不同组扩增的uncA基因进行测序，发现存在Hph I和Mbo II识别位点的变异。
本研究表明变形链球菌F-ATP酶的uncA基因明显表现出遗传多样性。不同的Hph I-RFLP和Mbo II-RFLP基因型可能与变形链球菌菌株的致龋性和耐酸性有关。
