Initial biofilm formation in caries-active and caries-inactive individuals

龋齿仍然是世界范围内流行率最高的传染病，具有相当大的经济意义。最初的生物粘附和牙膜的形成对于在牙齿表面形成致龋生物膜是必不可少的。然而，到目前为止，尚未对原位膜的功能和结构及其初始细菌定植进行龋活性和龋易感性的评估。在提交的项目中，首次对龋齿活跃和龋齿不活跃的成人受试者的膜膜进行结构，功能和初始细菌定植的表征。为此目的，将应用酶、电子显微镜和荧光显微镜技术；用生物分子技术（DGGE, T-RFLP）评估贴壁细菌。此外，还将利用分子质谱技术对附着的变形链球菌进行研究。重点是葡萄糖基转移酶（GTF），其产物（葡聚糖）及其与其他膜组分以及与粘附细菌的相互作用。GTFs是生物膜形成过程中相关的关键蛋白，但目前仅在体外研究了GTFs与其他膜组分的相互作用。它的目的是表征初始生物粘附过程相对于个别龋活性的细节。研究结果将有助于基础研究以及制定预防龋齿的新策略。

Caries still is the infectious disease with highest prevalence worldwide and it is of considerable economic relevance. Initial bioadhesion and pellicle formation are essential for the establishment of a caries-pathogenic biofilm on the tooth surface. However, until now function and structure of the in situ pellicle and its initial bacterial colonization have not been evaluated so far with respect to caries activity and caries susceptibility. For the first time the pellicles of caries-active and caries inactive adult subjects will be characterized with respect to structure, function and initial bacterial colonization in the submitted project. For this purpose, enzymatic, electron-microscopic and fluorescence-microscopic techniques will be applied; the adherent bacteria will be evaluated with biomolecular techniques (DGGE, T-RFLP). In addition, the adherent S. mutans species will be explored with molecular mass spectrometry. Strong emphasis is laid on glucosyltransferases (GTF), their products (glucans) and their interactions with other pellicle components as well as with the adherent bacteria. GTFs are relevant key proteins for the process of biofilm formation, but up to now, the interactions of GTFs with other pellicle components have only been investigated in vitro. It is aimed to characterize the process of initial bioadhesion with respect to the individual caries activity in detail. The results will contribute to basic research a as well as to development of new strategies in caries prevention.