Cell volume regulation in Claviceps fusiformis. An animal‐type Na,K‐ATPase operating in a fungus?

Claviceps fusiformis, an ergot pathogen of pearl millet, was equilibrated in media without and with 0.1 mM ouabain (g‐strophantin). Highly significant effects of ouabain on the contents of sodium ions and water were found, suggesting that an active transport of sodium ions, similar to that in animal cells, regulates the cell volume of the fungus. The basic role of the sodium pump appears to be to decrease larger cell volumes and to increase the small ones; for this purpose it can even reverse its direction.