FIG. 4.
Urease activity of wild-type 26695 H. pylori strain (black bars) and its isogenic hspA-ΔC mutant (gray bars) grown in liquid Brucella broth at pH 7 or pH 5 in unsupplemented medium or medium with added NiCl2 (100 μM). Error bars represent the standard deviations for three to four independent cultures.