title: Spontaneous and induced variability in Streptomyces nogalater producing nogalamycin.
abstract: Variability in the production of nogalamycin by Streptomyces nogalater var. nogalater was followed in untreated and mutagenized populations of the standard strain NRRL 3035 and its spontaneous variant K-18 using the method of agar blocks with subsequent tests under submerged conditions. In both strains the most active variants were obtained by natural selection without mutagenic treatment; in this way productivity increased by 108% after two selection steps. Treatment with UV-radiation did not yield variants with a highly increased activity. Gamma-radiation extended the variability but, at the same, substantially increased the number of non-producing and low-producing isolates. Relatively high yields of (+)-variants were obtained after treatment with nitrous acid but their activity did not reach that observed in the most active spontaneous variants.
mesh_terms: D001431:Bacteriological Techniques; D003470:Culture Media; D007101:Immersion; D009279:Naphthacenes / Q000096:biosynthesis*; D009621:Nogalamycin / Q000096:biosynthesis* / Q000302:isolation & purification; D013302:Streptomyces / Q000378:metabolism*
chemical_list: D003470:Culture Media; D009279:Naphthacenes; D009621:Nogalamycin