Objective: Dental caries is closely associated with biofilm formed on the tooth surface. Mutans streptococci play an important role in dental biofilm formation. Glucosyltransferases (GTFs), fructosyltransferase (FTF), and the exopolysaccharides they produce, facilitate bacterial adherence, biofilm formation, and enhance the virulence properties of the biofilm. Studies have shown that non-dialyzable material (NDM) derived from cranberry juice, inhibits enzymatic action of GTF and FTF. In this study we examined the effect of NDM on gene expression of these enzymes. Methods: NDM was obtained by dialysis of cranberry juice followed by lyophilization.
S. mutans were preincubated without or with 0.2 and 1 mg/ml of NDM and then grown in solution and in biofilm formed in a constant-depth film fermenter (CDFF). Total RNA isolation, cDNA synthesis and Real Time RT PCR were performed for planktonic and biofilm growth conditions. Results: A significant downregulation (2500 fold) of
ftf expression in planktonic condition. In contrast, the downregulation effect of NDM on
ftf expression in biofilm was not significant. Reduction of
gtfB mRNA synthesis was susceptible in planktonic (500 fold) and biofilm bacterial growth conditions (6700 fold). The effect of NDM on
gtfC transcription was less pronounced but also signigicant;downregulation 20 fold in solution and 70 fold in biofilm. Conclusions: The data support the notion that the anti-biofilm activity of NDM is by at least two mechanisms: (i) cell surface antiadhesion and (ii) specificaly downregulation of
gtf and
ftf mRNA synthesis.
This study was supported in part by Cabakoff Research Grant.