title: [Selection of strains of Streptomyces griseus Kr., the producer of a streptothricin antibiotic grisin, using the method of protoplast fusion].
abstract: The effect of protoplasting on antibiotic activity of the grisin-producing organism was shown. High frequency of Grn- mutants after strain VG307f protoplasting and no capacity in these mutants for reversion to the initial Grn+ phenotype were shown. The reversion frequency was less than 10(-8). Moreover, it was shown that all the Grn- mutants lost their stability (GrnR) to the effect of their own antibiotic. With respect to strain VG212 there was noted a significant increase in the number of both the minus and the plus variants after the protoplast formation and regeneration. Fusing of protoplasts of strains VG307f and VG212 belonging to the divergent lines in selection of S. griseus Kr. yielded the phage stable strain VG7849 with high levels of the antibiotic production and improved technological properties.
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis; D011523:Protoplasts; D011995:Recombination, Genetic; D012641:Selection, Genetic; D013305:Streptomyces griseus / Q000235:genetics* / Q000378:metabolism / Q000648:ultrastructure; D013309:Streptothricins
chemical_list: D000900:Anti-Bacterial Agents; C005960:grisein; D013309:Streptothricins
vernacular_title: Selektsiia shtammov Streptomyces griseus Kr., produtsenta streptotritsinovogo antibiotika grizina, s ispol'zovaniem metoda sliianiia protoplastov.