FIG 2.

Growth rate of the ΔrgpF mutant is impaired. Cultures of S. mutans UA159 (A), ΔrgpF (B), and rgpF⁺ (C) strains were grown in BHI medium or BHI medium titrated to pH values between 5.4 and 7.4. Growth was assessed by measuring optical density at 600 nm in a Bioscreen C plate reader (as described in Materials and Methods). Data are represented as mean ± standard deviation (SD) (n = 10). The calculated doubling times from graphs are displayed in Table 1.