Expression of selected genes analyzed by RT-PCR. Comparison of RT-PCR expression values for selected genes of S. mutans, grown on different surfaces. SMU.81, SMU.82 (dnaK) and SMU.1954 (groEL) are stress-related genes; SMU.574c, SMU.609, and SMU.987 are associated with cell wall proteins. SMU.744 codes for FtsY, while SMU.618 codes for a hypothetical protein. The data are expressed as the means of at least two biologically independent experiments.