Methods: NDM was dialyzed from cranberry juice and then lyophilized. For examining the continues effect of NDM on gene expression- S. mutans were grown overnight with various NDM concentrations and then diluted 1:30 with fresh inoculum and further incubated untill reaching a Log phase. For testing the immediate activity of NDM - 1:30 diluted inoculum of stationary phase grown bacteria was incubated with 1:30 diluted NDM untill reaching Log phase. Total RNA isolation, cDNA synthesis and Real Time RT PCR were performed for both experiments on gtfB, gtfC and ftf.
Results: NDM down-regulates ftf and gtf expression in both time conditions. It's continues effect with maximum concentration of 1 mg/ml was statistically significant : more than 90% reduction for all gene expression compare to control-without NDM. The immediate effect of the same concentration diluted 1:30 was less pronounced: ftf and gtfB mRNAs decreased about 50%, while gtfC expression was downregulated on 25% compare to control.
Conclusion: The data support that antiadhesion effect of NDM is performed at least by two mechanisms; In addition to inhibition of FTF and GTF activity, NDM alteres also gene expression of these enzymes in time dependent manner.