Evaluation of planktonic cells and biofilm characteristics from different genotypes of Streptococcus mutans prevalent in in situ cariogenic biofilm

• Grant number: 05/03089-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: March 01, 2006
• End date: February 28, 2010
• Field of knowledge: Health Sciences - Dentistry
• Principal Investigator: Cinthia Pereira Machado Tabchoury
• Grantee: Rodrigo Alex Arthur
• Host Institution: Faculdade de Odontologia de Piracicaba (FOP). Universidade Estadual de Campinas (UNICAMP). Piracicaba , SP, Brazil

Abstract

Previous results (Arthur et al., 2005) show selection of Streptococcus mutans genotypes on dental biofilm formed in situ at a high cariogenic challenge. In this acid environment, S. mutans develops protection mechanisms, like an increase in a proton-translocating ATPase and changes in the lipid composition of cellular membrane. Then, the aim of this study is to evaluate the bacterial viability, F-ATPase activity and lipidic composition of cellular membrane of S. mutans genotypes (Arthur et al., 2005) through a planctonic cell assay and on in vitro biofilm, in which the glycolytic pH drop, intra and extra cellular polysaccharides and atpD gene expression will be determined. For this, the S. mutans genotypes more prevalent on dental biofilm formed in situ and in vivo under a high and low cariogenic challenge (Arthur et al., 2005) will be grown in pH 7.0. The cultures will be harvested and suspended in a pH 5.0 or 2.8 buffer and after 30, 60 and 90 minutes, the bacterial viability will be determined. In this occasion, aliquots will be collected to determine the lipidic composition of membrane and ATPase activity. For the in vitro biofilm assay, the same genotypes of the planctonic assay will be used, grown in a medium with sucrose 1%, with glass slides, for 5 days. Glucose 1% will be added to this biofilm and, after this, the pH drop will be determined. Part of the biofilm will be collected and submitted to the same analyses described for the planctonic assay, and the other part of this biofilm will be used to determine the soluble and insoluble extra cellular polysaccharides, the intracellular polysaccharides and the atpD gene expression.

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

ARTHUR, Rodrigo Alex. Evaluation of phenotypic traits of cariogenicity of Strptococcus Mutans genotypes isolated from dental biofilm. 2010. Doctoral Thesis - Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba Piracicaba, SP.