Osmotic adjustment in the mycelial ascomycete Neocosmospora vasinfecta (E. F. Smith)

Osmotic adjustment in the ascomycete Neocosmospora vasinfecta was investigated by determining intramycelial water, mycelial solutes, and total mycelial osmolality. Major organic and inorganic solutes as well as proline and glycine betaine were determined under conditions of osmotic stress and shock, imposed by 0.5 M KCl. Comparison to glucose as a nonelectrolytic osmoticum was also made. Results quantitatively implicated the polyhydric alcohols as the osmotic adjusters. Changes in amino acids were due to growth and were not osmoregulatory in nature. The osmoticum was not utilized for osmotic adjustment. The growth of N. vasinfecta in the presence of KCl indicated that this organism is moderately sensitive to osmotic stress.