Molecular analysis of the developmental mechanism of periodontal and oral diseases by the genome analysis of oral biofilm.

牙菌斑具有生物膜的特性，类似于身体和环境中发现的其他生物膜。现代分子生物学技术已经在牙科生物膜中鉴定出大约1000种不同的细菌，是所能培养的细菌数量的两倍。口腔生物膜在结构上具有很强的异质性。然而，基因组信息与口腔和牙周疾病的发展之间的关系仍然是模糊的。本研究主要围绕两个主题展开：(1)口腔链球菌基因组变异分析(2)牙龈卟啉单胞菌对口腔上皮细胞的致病机制研究(1)口腔链球菌基因组变异分析。变形杆菌菌株分为四个血清型(c、e、f和k)。然而，关于变形链球菌的种群，包括菌株之间的克隆关系，人们知之甚少。我们开发了一种针对变形链球菌的多位点序列分型(MLST)方案。对8个看家基因片段进行了…测序从102个变形链球菌中各分离出更多。我们在这102株菌株中确定了92种序列类型，表明变形链球菌包含一个多样化的群体。没有发现地理特异性。然而，胶原结合蛋白基因(CNM)的分布和母婴传播的直接证据是明显的。我们还对变形链球菌NN2025菌株进行了全基因组测序，其基因组在复制子上具有广泛的基因组排列。(2)牙龈卟啉单胞菌对口腔上皮细胞的致病机制。牙龈卟啉单胞菌是一种牙周病原体，其菌毛根据编码每个菌毛亚单位的FIMA基因的多样性被分为六种基因类型。提示具有II型菌毛的牙龈假单胞菌比I型菌株毒力更强。用II型FIMA替换I型FIMA可增强细菌对上皮细胞的黏附/侵袭，而替换I型FIMA则导致效率降低。这些结果表明，II型菌毛是牙龈假单胞菌毒力的关键决定因素。较少

Dental plaque has the properties of a biofilm, similar to other biofilms found in the body and the environment. Modern molecular biological techniques have identified about 1000 different bacterial species in the dental biofilm, twice as many as can be cultured. Oral biofilms are very heterogeneous in structure. However, the relationship between the genomic information and the development of oral and periodontal diseases are still ambiguous. In this study, we focused on two theme, (1) Analysis of genomic variation of oral streptococci (2) Pathogenic mechanism of Porphyromonas gingivalis against oral epithelial cells.(1) Analysis of genomic variation of oral streptococciS. mutans strains have been classified into four serotypes (c, e, f, and k). However, little is known about the S. mutans population, including the clonal relationships among strains of S. mutans. We have developed a multilocus sequence typing (MLST) scheme for S. mutans. Eight housekeeping gene fragments were sequenced … More from each of 102 S. mutans isolates. We identified 92 sequence types in these 102 isolates, indicating that S. mutans contains a diverse population. No geographic specificity was identified. However, the distribution of the collagen-binding protein gene (cnm) and direct evidence of mother-to-child transmission were clearly evident. We also performed the whole genome sequencing of the S. mutans NN2025 strain, and its genome had an extensive genomic arrangement across the replicore.(2) Pathogenic mechanism of Porphyromonas gingivalis against oral epithelial cells.Porphyromonas gingivalis is a periodontal pathogen whose fimbriae are classified into six genotypes based on the diversity of the fimA genes encoding each fimbria subunit. It was suggested that P. gingivalis strains with type II fimbriae were more virulent than type I strains. The substitution of type I fimA with type II enhanced bacterial adhesion/invasion to epithelial cells, whereas substitution with type I fimA resulted in diminished efficiency. These results suggest that type II fimbriae are a critical determinant of P. gingivalis virulence. Less