Involvement of CO2 generated by urease in multiplication of Helicobacter pylori

Helicobacter pylori (H. pylori) urease generates both ammonia (NH₃) and carbon dioxide (CO₂) from urea. NH₃ helps H. pylori to survive in the stomach in part by neutralizing gastric acid. However, the relationship between CO2 and H. pylori is not completed cleared. We examined the effect of CO₂ generated by urease on multiplication of H. pylori by using isogenic ureB mutant and ureB complemented strain from H. pylori strain JP26. Wild-type strain survived in the medium supplement with 1mM urea in room air, however, the urease negative strain did not. To discern whether CO₂ was incorporated into H. pylori, ¹⁴C in bacillus was counted after 6 hours incubation with ¹⁴C urea in both acidic and neutral medium. Significant more ¹⁴C uptake was detected in wild-type strain compared to ureB mutant strain and this uptake in the wild-type strain was more under acidic condition compared to under neutral condition, but no difference was identified in the mutant strain. These results suggest that CO₂ generated by urease plays a role in multiplication of H. pylori.