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Variability of the two components system FimSR and expression of fimA in Porphyromonas gingivalis.

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Author(s):
Sílvia Regina Loureiro Teixeira
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
Defense date:
Examining board members:
Marcia Pinto Alves Mayer; Magda Feres; Marilis do Valle Marques; Roxane Maria Fontes Piazza; Denise Madalena Palomari Spolidorio
Advisor: Marcia Pinto Alves Mayer
Abstract

The aim of this study was to test the hypothesis that polymorphism in genes encoding the two-component system FimSR and their transcription levels would influence the expression of fimbriae and adhesion of Porphyromonas gingivalis. We evaluated 21 clinical strains and reference strains 33277 (fimbriate) and W83 (non fimbriated). The presence of a capsule was determined in 13/21 strains and the presence of fimbriae in 15/21. All strains were able to adhere to the cells (efficiency from 1.2 to 6.1%). There was no correlation between genotypes fimA, presence of fimbriae / capsule and macrorestriction profiles by PFGE. Differences in transcription of fimA could not be attributed to differences in the promoter region of fimS. fimA was upregulated after interaction with epithelial cells in most strains. The data indicate that regulation of fimA is strain specific. Non-fimbriated strains may have other strategies to adhere to epithelial cells, suggesting that in addition to fimbriae, other structures could play a role in the interaction of that specie with cells. (AU)