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Updated: Jan 18, 2026
A Mass Spectrometry-Based Approach to Identify Phosphoprotein Phosphatases and their Interactors
Published on: April 29, 2022
Electron microprobe X-ray analysis of polyphosphate granules in Plesiomonas shigelloides
Abstract:
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.
Insights
Electron-dense inclusion bodies were observed in Plesiomonas shigelloides. These bodies, containing phosphorus, potassium, and magnesium, resemble polyphosphate granules found in other bacteria.
Area of Science:
- Microbiology
- Bacteriology
- Cell Biology
Background:
- Plesiomonas shigelloides is a Gram-negative bacterium.
- Inclusion bodies are intracellular structures observed in various microorganisms.
- The composition and function of inclusion bodies in P. shigelloides were previously uncharacterized.
Purpose of the Study:
- To investigate the presence and characteristics of electron-dense inclusion bodies in Plesiomonas shigelloides.
- To determine the elemental composition of these inclusion bodies.
Main Methods:
- Transmission electron microscopy (TEM) for visualizing inclusion bodies.
- Electron microprobe X-ray analysis for elemental composition determination.
Main Results:
- Electron-dense inclusion bodies were consistently found in Plesiomonas shigelloides cells.
- Inclusion body size varied with incubation time, increasing to be visible under light microscopy during the logarithmic growth phase.
- Elemental analysis revealed the presence of phosphorus, potassium, and magnesium within the inclusion bodies.
Conclusions:
- The observed inclusion bodies in Plesiomonas shigelloides share elemental similarities with polyphosphate granules.
- These findings suggest that Plesiomonas shigelloides may store polyphosphate granules intracellularly.
- The study provides insights into the ultrastructure and elemental composition of Plesiomonas shigelloides.
