Sodium efflux from perfused giant algal cells
1Botany Department, University of Cambridge, Downing Street, CB2 3EA, Cambridge, UK.
Planta
|November 15, 2013
Summary
Sodium efflux in perfused Chara cells is ATP-dependent and linked to proton gradients. This suggests a secondary antiporter mechanism, crucial for understanding ion transport in plant cells.
Area of Science:
- Plant Physiology
- Ion Transport Mechanisms
- Cell Biology
Background:
- The giant alga Chara corallina is a model organism for studying cellular transport.
- Understanding sodium efflux is vital for plant cell homeostasis and function.
Purpose of the Study:
- To investigate the mechanisms of sodium efflux in internally perfused Chara corallina cells.
- To elucidate the role of ATP and proton gradients in regulating sodium transport.
Main Methods:
- Internal perfusion of Chara corallina internodal cells with artificial cytoplasm.
- Measurement of sodium-22 efflux under varying internal and external conditions.
- Assessment of ATP-dependence and inhibition by amiloride and N,N'-dicyclohexylcarbodiimide.
Main Results:
- Sodium efflux increased with internal sodium concentration and decreased external pH.
- Efflux was significantly inhibited by amiloride and was highly ATP-dependent.
- N,N'-dicyclohexylcarbodiimide reduced ATP-dependent efflux, and membrane potential remained stable.
Conclusions:
- Sodium efflux in perfused Chara cells likely occurs via a secondary antiporter with protons.
- ATP acts catalytically, and proton motive force provides energy for this transport system.
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