Electron microprobe X-ray analysis of polyphosphate granules in Plesiomonas shigelloides.

Electron-dense inclusion bodies were found in most Plesiomonas shigelloides cells, regardless of the incubation time. At the 4-hr incubation period, the size of inclusion bodies was distributed in the range of 50 to 150 nm in diameter, and at the logarithmic phase of growth it increased up to a size visible by light microscope. By an electron microprobe X-ray analysis, phosphorus, potassium, and magnesium were detected in the inclusion bodies which confirms the assumption of Pastian and Bromel (Appl. Environ. Microbiol. 47: 216 (1984] that the inclusion bodies have a very similar elemental composition to the polyphosphate granules of C. diphtheriae.