31] Detection of streptococcal glucan-binding proteins in biofilms

Abstract

Publisher Summary Extracellular and cell-bound glucosyltransferases (GTFs) produce α- 1,6 and/or α- 1,3 glucans from the sucrose. The glucans seem to be required for biofilm development because a-glucanases are able to suspend the adherent cells. Glucan-binding proteins contribute to the integrity of the biofilm matrix. The glucan-binding proteins (GBPs), including a glucan-binding lectin (GBL), appear to be both cell-associated and secreted. An enhanced chemiluminescence (ECL) method for GBPs developed by Galperin et al. is adapted to study sucrose-dependent biofilms of Streptococcus sobrinus. This chapter provides a schematic for the ECL method. Proteins were recovered from cells and supematants of planktonic cultures and biofilms, subjected to sodium dodecyl sulfate gel electrophoresis, and transferred onto polyvinylidene difluofide for ECL analysis. Biofilm cells contain numerous GBPs ranging in molecular weight from 40,000 to > 150,000. Supernatants of biofilm cultures had only one major protein, suggesting that most of the GBPs are involved in biofilm formation. The ECL technique allows for the detection of multiple GBPs and permits a rapid comparison between planktonic and biofilm conditions.