[Effect of mutagenic factors on the variability of cultures of Actinomyces griseus--preducer of the antibiotic grisin].

The study of the lethal and mutagenic effect of ethylenimine, nitrozoguanidine, nitrozomethylurea and nitrozoethylurea on Act. griseus Krainsky 15, producing grisin, an antibiotic widely used in agriculture as a stimulator of domestic animal growth showed that induction of mutants with increased antibiotic production levels was most favourable under the effect of ethylenimine. The above mutagens were highly active with respect to induction of morphological mutants. No clear correlation between the colony morphology and antibiotic production property was observed. However, it was noted that the dwarf colonies had a significantly decreased antibiotic activity.