Identification of structures containing polyphosphate in Helicobacter pylori

For the first time polyphosphate (poly P) granules have been detected in Helicobacter pylori organisms colonizing the gastric antrum as well as in organisms isolated from the same tissue. Poly P granules showed typical sublimation characteristics during exposure to the electron beam and chipped out of ultrathin sectioning. A prominent phosphorus signal was identified using elemental specific electron microscopy such as electron energy loss spectroscopy (EELS) and was localized to at least three different locations: the cytoplasm, the flagellar pole and in association with the cell membrane. Intracytoplasmatic structures had a diameter of 0.05-0.2 micron, whereas the structures near the flagellar pole were much smaller (0.02 micron). The membrane-associated phosphate aggregates were visible only after staining with Pb(NO3)2 or with electron spectroscopic imaging (ESI). Poly P granules seem to be important energy and phosphorus stores and it is thought that they participate in the regulation of various and distinct metabolic processes of H. pylori.