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The cytotoxic action of leucocidan from Pseudomonas aeruginosa on human polymorphonuclear leucocytes
Abstract:
Human polymorphonuclear leucocytes treated in vitro with leucocidin from Pseudomonas aeruginosa underwent characteristic morphological alterations as shown by phase-contrast and scanning electron microscopy. Within a few minutes of exposure to leucocidin the granulocytes became round, and protoplasmic extrusions appeared on the cell membrane, were withdrawn again and put out at another point of the cell. The final stage of the leucocidin-treated leucocyte was an enlarged, rounded vesicle with apparently intact plasma membrane. Omission of calcium ions from the diluting buffer caused certain differences in the morphologic appearance of the damaged leucocytes.
Insights
Pseudomonas aeruginosa leucocidin causes significant cell shape changes in human polymorphonuclear leucocytes. These changes include cell rounding and membrane alterations, with calcium ions influencing the damage.
Area of Science:
- Microbiology
- Cell Biology
- Immunology
Background:
- Pseudomonas aeruginosa is an opportunistic pathogen.
- Leucocidins are toxins produced by bacteria.
- Polymorphonuclear leucocytes are key immune cells.
Purpose of the Study:
- To investigate the morphological effects of Pseudomonas aeruginosa leucocidin on human polymorphonuclear leucocytes.
- To observe the dynamic changes in leucocyte structure upon toxin exposure.
Main Methods:
- In vitro treatment of human polymorphonuclear leucocytes with Pseudomonas aeruginosa leucocidin.
- Phase-contrast microscopy.
- Scanning electron microscopy.
Main Results:
- Leucocidin induced rapid cell rounding and protoplasmic extrusions on the leucocyte membrane.
- Observed dynamic membrane activity with extrusion and retraction of protrusions.
- The final cell morphology was an enlarged, rounded vesicle with an intact plasma membrane.
- Calcium ion omission altered the appearance of damaged leucocytes.
Conclusions:
- Pseudomonas aeruginosa leucocidin induces distinct and rapid morphological changes in human polymorphonuclear leucocytes.
- The observed cellular alterations suggest a significant impact on leucocyte function.
- Calcium ions play a role in modulating the cytotoxic effects of leucocidin on leucocytes.