FIG 7.

Phenotypic characterization of the kdpA mutant. (A) Growth of the wild-type strain and kdpA mutant in different potassium concentrations. Cells from ON cultures were washed with M2-K and inoculated into M2 medium or M2-K with increasing concentrations of KCl added as indicated. The growth was determined by measuring the OD₆₀₀ of the cultures after 24 h at 30°C with agitation. [K⁺] is indicated in mM; M2, standard M2 minimal medium. (B) Growth of the wild-type strain and kdpA mutant in M2-K with either 100 μM or 1 mM KCl, incubated at 30°C or 10°C with agitation. (C) Cultures of the wild-type strain and kdpA mutant were grown in M2 medium at 10°C for 24 h and then transferred to 30°C at the time indicated (arrow). The lines indicate the averages and the vertical bars the standard deviation for each time point. The growth at 30°C was measured every 15 min and at 10°C every 4 h at the indicated time points.