FIG. 2.

Promoter activity of tagA under phosphate starvation and phosphate-replete conditions. Strains containing the tagA-lacZ fusion in the parent strain or the phoP or phoR mutant strain were grown in LPDM (0.42 mM) or HPDM (5 mM) as described previously (10). A 12-h growth was monitored with respect to optical density at 540 nm, (OD540), APase activity, and β-galactosidase, which represents promoter activity. (A and B) APase and β-galactosidase activities, respectively, in LPDM; (C and D) APase and β-galactosidase activities, respectively, in HPDM. Open symbols, growth; filled symbols, APase or β-galactosidase activity. Strains included MH5630 (squares [parent]), MH5632 (diamonds [phoR]), and MH5634 (circles [phoP]).