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Volume regulation in Mycoplasma gallisepticum
Israel Journal of Medical Sciences
|September 1, 1984
Summary
Mycoplasma gallisepticum cells swell and lyse in high salt conditions due to osmotic and Donnan forces. Glucose addition reverses swelling, indicating a role for energy-dependent ion transport mechanisms.
Area of Science:
- Microbiology
- Cell Biology
- Biophysics
Background:
- Mycoplasma gallisepticum is a significant avian pathogen.
- Understanding cellular responses to osmotic stress is crucial for pathogen survival and control.
Purpose of the Study:
- To investigate the mechanisms of cell swelling and lysis in Mycoplasma gallisepticum under hyperosmotic conditions.
- To elucidate the role of ion transport in regulating cell volume.
Main Methods:
- Incubation of Mycoplasma gallisepticum cells in 250 mM NaCl.
- Addition of non-diffusible solutes (sucrose, MgSO4) and glucose to assess their effects on cell volume.
- Monitoring of Na+ and H+ movement.
Main Results:
- High salt (250 mM NaCl) induced significant cell swelling and subsequent lysis.
- Non-diffusible solutes prevented swelling, supporting the involvement of colloid osmotic and Donnan forces.
- Glucose addition during swelling caused cell shrinkage, restoring initial volume.
- Ion movement studies indicated an ATP-driven H+ pump and Na+/H+ exchange.
Conclusions:
- Mycoplasma gallisepticum cells are susceptible to osmotic lysis in hypertonic environments.
- Cell volume regulation involves active ion transport, including proton pumping and sodium-proton exchange.
- Glucose metabolism likely fuels these ion transport systems to counteract osmotic stress.