FIG. 2.

Induction of APase and β-galactosidase in phyC-lacZ fusion strains. (A) Expression of β-galactosidase by strain OM611, which contains an FZB45 phyC-lacZ fusion, under three different phosphate concentrations (filled symbols). Growth of the cultures is indicated by open symbols linked by dashed lines. The symbols are given as an average range of phosphate concentrations according to measurements performed during cultivation. (B) phyC promoter activity in strain OM611 (wild type) (diamonds) or strain OM621 (phoP) (circles). Both strains were grown in LPM (solid symbols) and HPM containing 10 mM phosphate (open symbols). (C) Growth and APase activity of OM611 (diamonds) or OM622 (phoP) (circles) in HPM (open symbols) and LPM (solid symbols). APase activity was measured as a control for the PhoP-negative phenotype. The experiments were repeated at least three times, with similar results.