FIG. 2.

Neutral and base shift growth curves. B. subtilis strain AG174 overnight cultures in unbuffered LBK were diluted 500-fold into LBK buffered at pH 6.0 (•) and at pH 7.4 (○) and cultured until an OD₆₀₀ of 0.3. The culture at pH 6.0 was then diluted 10-fold into medium at pH 7.4 (▾) and pH 6.0 (•). The culture at pH 7.4 was diluted 10-fold into medium at pH 8.8 (▿) and pH 7.4 (○). Diluted cultures were incubated for 2.5 h. The average of three biological replicates is shown; error bars represent the SEM.