Acid acclimation by Helicobacter pylori

Helicobacter pylori is a Gram-negative neutralophile associated with peptic ulcers and gastric cancer. It has a unique ability to colonize the human stomach by acid acclimation. It uses the pH-gated urea channel, Urel, to enhance urea access to intrabacterial urease and a membrane-anchored periplasmic carbonic anhydrase to regulate periplasmic pH to similar to 6.1 in acidic media, whereas other neutralophiles cannot regulate periplasmic pH and thus only transit the stomach.