Molecular Analysis of Oral Streptococcal Biofilm

Dental plaque, the most complex biofilm found in human body, is closely associated with chronic diseases such as caries and periodontal disease. Occasionally, plaque microbes can cause life-threatening endocarditis in individuals with prosthetic heart valves or predisposing heart valve damages. A link between chronic periodontal diseases and several systemic infections has also been observed in recent decades, indicating that oral infection is a significant risk-factor for systemic diseases. The development of dental plaque is initiated by the adhesion of oral streptococci to the pellicle coated tooth surface. The binding of pioneer species such as Streptococcus parasanguinis provides substrates for the subsequent attachment of other oral bacteria. Thus, the attachment of primary colonizers to the tooth surface is critical for the development of dental microbial communities. To better understand the mechanism governs the interactions between plaque microbes, and to search for potential therapeutic agents for controlling oral biofilm, this proposal aims to isolate and characterize genetic components required for biofilm formation in one of the pioneer colonizers, S. parasanguinis FW213. The specific aims are, first, to identify and characterize the gene products of S. parasanguinis that are essential for biofilm formation or for genetic control of biofilm growth using a transposon mutagenesis strategy. Second, to determine the ecological impact of each specific mutation defined in Aim 1 in biofilm formation by using a defined, multi-species biofilm system. Third, to determine the inhibitory functions of various natural and synthetic compounds on oral biofilm formation. The results of this proposal will uncover signaling pathways required for biofilm programming. Such information will provide practical knowledge for the development of novel therapeutic strategies to promote healthy composition of dental biofilm flora.

Project ID:PC9808-0559
External Project ID:NSC98-2320-B182-031-MY3