A nutritional study of eight strains of Gymnoascus reessii

Summary Eight strains ofGymnoascus reessii representing several morphological variants were grown in media which contained a variety of carbon and nitrogen sources in order to determine whether there was a correlation between morphological variation and physiological characteristics. Seven strains were similar in their assimilatory abilities, while one strain, 0-309 (NRRL 3612), was consistently dissimilar from the others. The defined medium which permitted the most growth of all eight isolates contained glycine as the nitrogen source and glucose as the carbon source. Other good, defined sources of carbon and nitrogen included soluble starch, maltose, KNO₃ and NaNO₃. Peptone and casamino acids were effective nitrogen sources also. Seven strains grew better with added growth factors although they did not have an absolute requirement for such factors. The other strain, 0-309, appeared to have a growth factor deficiency. Seven of the eight strains were basically similar in their nutritional characteristics. Only strain 0-309 (NRRL 3612) consistently demonstrated sufficient differences so that it could possibly be considered to be a variety ofG. reessii.