Mutational analysis of P. gingivalis genes up regulated during the biofilm formation with S. gordonii

• Grant number: 05/00529-5
• Support Opportunities: Regular Research Grants
• Start date: May 01, 2006
• End date: April 30, 2009
• Field of knowledge: Health Sciences - Dentistry - Periodontology
• Principal Investigator: Maria Regina Lorenzetti Simionato
• Grantee: Maria Regina Lorenzetti Simionato
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Porphyromonas gingivalis is a Gram negative anaerobe rod and when present or overrepresented within the oral biofilms may contribute to the initiation and progression of severe forms of periodontal diseases. P. gingivalis is a late or secondary colonizer of the oral biofilm, a process that is facilitated by other microbial species that provide attachment sites, as well as supply growth substrates, and reduce oxygen tension to optimal levels for growth of P. gingivalis. Among the early plaque organisms that P. gingivalis adheres to are the oral streptococci, especially Streptococcus gordonii. In a previous study using microarray technology, we detect 33 genes that were up-regulated when P. gingivalis was in contact with S. gordonii cells. Then, five of these up-regulated P. gingivalis genes were selected to investigate their possible role on P. gingivalis biofilm formation. Therein the main objective of this study is to construct 5 mutants of P. gingivalis 33277 by knocking out the folowing selected genes: PG0047 (Cell division protein-FtsH), PG0432 (NOL1/NOP2/sun family protein), PG0686 (Conserved hypothetical protein), PG0707 (TonB-dependent receptor), and PG1641 (Phosphotyrosine protein phosphatase). After that it is also proposed to verify if these genes are involved in the P. gingivalis abilities to participate in the biofilm formation by comparying the results from the mutants with that from the parental strain, using either a quantitation in a mixed-species biofilm model or analyzing the biofilm structure by confocal microscopy. (AU)