FIG 2 .

Effect of Ni on urease synthesis in WT or Δmua mutant bacteria. Shown is SDS-12.5% PAGE of 5 µg of cell-free extracts of WT strain 26695 or the 26695 Δmua mutant (A) or WT strain 43504 and the 43504 Δmua mutant (B). Cells were grown on medium without supplemental Ni (BA) or on medium with 50 µM supplemental Ni (BA 50). UreA and UreB are indicated by arrows, and the positions of molecular mass standards are indicated on the right. (C) Five micrograms of cell-free extracts of the WT strain (26695) or the 26695 Δmua mutant strain grown on medium without supplemental Ni (BA) or medium with 50 µM supplemental Ni (BA 50) was subjected to SDS-PAGE, transferred to nitrocellulose, and blotted with two antisera directed to subunits UreA and UreB. (D) Cell-free extracts (1 μ each) of the ΔnikR or Δmua ΔnikR mutant strain grown on medium without supplemented Ni (BA, left) or on medium with 50 µM supplemental Ni (BA 50, right) were separated on SDS-PAGE, transferred to nitrocellulose, and blotted with antiserum directed to the urease large subunit, UreB.