[Variability in Penicillium janthinellum Biourge, a producer of the antibiotic janthinellin, under the action of nitrosomethylurea].

Variation of the janthinellin-producing organism P. janthinellum was induced by nitrozomethylurea (NMU). The following concentrations of NMU were tested: 0.5; 0.25, 0.125 per cent at the exposure time of 15 minutes, 1 and 10 hours. The conidia survival had back dependence on the concentration and exposure time. The morphological variation was evident from the presence of forms with changed colour of the colony surface mycelium, light green, brown, light yellow, yellow-pink and white conidia and forms differing in the rate of the mycelium development and sporulation. The reverse surface of the colonies of both cultures was light brown to brown because of pigmentation. The feature of pigmentation was stable and no apigmented froms were obtained under the effect of NMU. Formation of variants producing higher yields of janthinellin (400, 2000 units) as compared to the activity of the control variant was noted. Plus variants were detected among the morphologically unchanged cultures.