FIG. 4.

Arginine rescues WT H. pylori 26695 but not the isogenic rocF::aphA3 mutant from acid exposure. H. pylori strains were treated with 0.1 M citrate-phosphate buffer at the pHs indicated in the presence or absence of 10 mM l-arginine, l-agmatine, or 20 mM urea. After 30 min, bacteria were washed, diluted, and plated to determine viable CFU. A representative experiment of three experiments, each conducted in duplicate, is shown. The log₁₀ CFU killed is as described in the legend to Fig. 3.