Methods: S. mutans KCTC3065 was maintained in 0.5% glucose and 1% xylitol (Sigma Chemical, MO, USA) containing TYE (BD Difco, MD, USA) media during 30d at 37°C 10% CO2 to form X-R. The same procedures without xylitol were repeated for the formation of X-S. Both were cultured in 0.5% glucose with or without 1% xylitol containing TYE media overnight and total RNA was extracted by TriReagent (Molecular Research Center, OH, USA). Probes which prepared with RNA from X-S as control was labeled with Cy3 dye (Arersham Pharmacia, Up-psala, Sweden) and X-R as references were labeled with Cy5. DNA chip (Mycroarray.com, MI, USA) was hybridized for 18-20h at 42°C. To identify of the results for DNA chip, RT-PCR was performed.
Results: A total of 277 genes of DNA chip data were significant increased or decreased in X-R. There is a total of 174 X-R up-regulated genes and a total of 103 down-regulated genes. The most abundant increased genes in X-R were related to cell envelope, cellular processes, DNA metabolism, transcription, and protein folding and stabilization. The decreased genes in X-R were related to amino acid biosynthesis, toxin production and resistance, energy metabolism, ribosomal proteins synthesis, and signal transduction.
Conclusion: These results indicate that the difference of gene expression profile of X-S and X-R may be in existence. In particular, results of this study for X-R up-regulated genes have a lot of similarities with the published xylitol-related researches and other functional studies.