Growth-phase-dependent expression of comC, comD, comE, and comX genes in cDNAs derived from SmuvicK, Smuvic+, and UA159 strains. S. mutans strains were grown to early-lag (OD of ∼0.2)-, mid-log (OD of ∼0.4)-, and late-stationary (OD of ∼0.8)-growth phases in THYE. Relative expression at the early-lag phase was set at a user-defined value of 1.0. The results are averages of triplicate samples from three independent experiments ± the standard error.