Fig. 4.
Effects of gradient changes on the distribution of H. pylori and H. felis in the juxtamucosal mucus of gerbils and mice, respectively. Each animal is represented by one dot, which indicates the mean density of bacteria in the animal under control conditions plotted against the mean density of bacteria in the same animal under test conditions. The dotted line is the ideal curve showing where the density of bacteria under control conditions is identical to that under the test conditions. (A) Bacterial densities remained unaffected after changes in the urea/ammonium gradient (blue line), luminal pH (green line), arterial pH (red line), and arterial bicarbonate concentration (pink line). For these gradients, only the mean regression line of all values for one test series is shown. (B) The density of H. felis and H. pylori in the juxtamucosal mucus decreased significantly after the combined reduction of the arterial bicarbonate and pH, which eliminated the mucus pH gradient.