FIG 8.

PhoB protein levels reach similar levels independently of growth history. (A and B) Dynamics of PhoB expression. WT cells with or without prestarvation of Pi were shifted to MOPS medium (50 μM Pi) at time zero. Equal ODs of bacteria were lysed and analyzed by Western blotting (A), and data were quantified (B). Phosphate became limited after ∼30 min (area shaded in gray). Data are shown as means ± SD of results from four immunoblots. (C) PhoB expression levels for cells with different growth histories. Prestarvation of Pi and growth dilution in Pi-replete medium were performed as described in Materials and Methods.