UREASE PLAYS AN IMPORTANT ROLE IN THE CHEMOTACTIC MOTILITY OF HELICOBACTER-PYLORI IN A VISCOUS ENVIRONMENT

Helicobacter pylori exhibits chemotactic responses to urea, flurofamid e, acetohydroxamic acid, and sodium bicarbonate, In buffer, the chemot actic activities of a urease-positive strain were higher than those of the isogenic urease-negative strain, Moreover, the chemotactic activi ties of the urease-positive strain mere increased in a viscous solutio n containing 3% polyvinylpyrrolidone, whereas those of the urease-nega tive mutant were not. These results are in accordance with the fact th at the mutant strain did not show swarming in motility agar regardless of having flagella, Incubation of the wild-type strain with flurofami de resulted in partial inhibition of the chemotactic activities in the viscous solution, In addition, incubation with acetohydroxamic acid, a low-molecular-weight, diffusible urease inhibitor, resulted in compl ete loss of chemotactic activity in the viscous solution. The inhibiti on of the chemotactic activity bg urease inhibitors paralleled the inh ibition of urease, The chemotactic activity of H. pylori was also inhi bited by the proton carrier carbonyl cyanide m-chlorophenylhydrazone, showing that H. pylori utilizes proton motive force for motility, Thes e results indicate that cytoplasmic urease plays an important role in the chemotactic motility of H, pylori under a condition that mimics th e ecological niche of the bacterium, the gastric mucous layer.