FIG 1.
A strain producing PhoB with a C-terminal 3×FLAG epitope behaves like the wild type (WT) under phosphate-replete and phosphate-limited conditions. (A) Growth curves of the strains indicated, in minimal medium with 10 mM or 50 μM phosphate. (B) β-Galactosidase assays for a PpstC-lacZ (left) and PpstS-lacZ (right) reporter in minimal medium with 10 mM phosphate (top) or 50 μM phosphate (bottom). The strains indicated were grown in minimal medium with 10 mM extracellular phosphate, washed, resuspended in medium with 10 mM or 50 μM phosphate, and grown for 7 h to an OD600 between 0.3 and 0.4. For panels A and B, data points indicate the averages of results from three independent replicates, with error bars representing the standard deviations (SD). (C) Phase-contrast microscopy of the indicated strains expressing wild-type phoB. Bars, 2 μm.