Abstract

Periodontal disease has been associated with poor dental care, which promotes the accumulation of bacteria and the development of diseases of the mouth. Porphyromonas gingivalis are anaerobic Gram-negative bacteria found in the subgingival plaque. They are largely responsible for chronic periodontal disease.Streptococcus intermedius is a Gram positive coccus found in the supragingival plaque. The objective of the present work was to evaluate the expression of several virulence genes of P. gingivalis in a mixed culture with S. intermedius using qPCR and heterologous microarrays. P. gingivalis ATCC 33277 and W83 and S. intermedius ATCC 27335 strains were cultured and total RNA was extracted using the High Pure RNA isolation kit. Oligodeoxynucleotides were designed to make multiple comparisons with organisms. Microarray was performed to identify gene expression.To quantify gene expression, cDNA samples from three different P. gingivalis:S. intermedius ratios were diluted 10^-1, 10^-2 and 10^-3. The microarray experiment indicated that in P. gingivalis, 29 genes were upregulated. The putative function of upregulated genes was the biosynthesis of different metabolic pathways.Heterologous microarrays are a new approach that are useful for investigating gene expression.

 Key words: Porphyromonas gingivalis, Streptococcus intermedius, periodontal disease, virulence genes, cross gene regulation.