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Identification of genes differentialy expressed in the biofilm formation of Porphyromonas gingivalis strains isolated from distinct clinical conditions, by using Differential Display PCR

Grant number: 05/04064-7
Support type:Regular Research Grants
Duration: May 01, 2006 - April 30, 2009
Field of knowledge:Health Sciences - Dentistry - Periodontology
Principal Investigator:Maria Regina Lorenzetti Simionato
Grantee:Maria Regina Lorenzetti Simionato
Home Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Porphyromonas gingivalis is a Gram negative anaerobe rod. Although a close association of P. gingivalis with periodontal diseases has been demonstrated in numerous studies, several aspects are not completely undestood yet. The presence of P. gingivalis at subcultivable levels at health gingival sites in adults or children, as well the presence of this pathogen at almost similar proportions in periodontal pockets undergoing destruction and pockets with unaltered depth, could be indicative of a heterogeneous species with subpopulations of low and high pathogenicity. P. gingivalis is a late or secundary colonizer of the dental biofilm, and S. gordonii is among the major early colonizers that P. gingivalis can adhere. Thus, bacteria in a biofilm environment can be phenotipically distinct from their planktonic counterparts. The developmental pathway involves localization at a surface, attachment to the surface, accretion at the surface, growth and division, and differentiation into a mature biofilm. Each one of these steps represents unique challenges to the bacterial cells to which they respond by the organized expression of a discrete set of genes. The objectives of this study are to analyze the ability of biofilm formation by the P. gingivalis strains isolated from different periodontal conditions as well the verification of the gene expression profile of these isolates cells, in planktonic or established in the biofilm, using Differential Display Reverse Transcription-PCR. After that it is also proposed to construct mutants by knocking out the genes differentialy expressed, for a further investigation of a possible role of these P. gingivalis genes in the structure or formation of the biofilm. (AU)