Immediate and transient inhibition of the respiration of Escherichia coli under hyperosmotic shock.

The respiration of Escherichia coli is severely inhibited, during hyperosmotic stress period, as a consequence of plasmolysis; deplasmolysis allows the cell to recover respiration. A mutant lacking all K+ transport systems can neither deplasmolyze nor recover respiration unless betaine is present in the medium. Betaine, in these conditions, increases both cytoplasmic volume and respiration; this suggests a control of respiration by cytoplasmic volume.