title: [Search for A factor-dependent variants in actinomycete population].
abstract: A study of 28 nocardia-like, asporogenous, and oligosporous spontaneous morphological variants belonging to 23 species of streptomycetes revealed five strains producing regulators of the A-factor group. Streptomyces griseus 1439, which forms aerial mycelium and spores only in the presence of exogenous A-factor was used as the test strain. Among the 28 spontaneous variants, three new A-factor-dependent strains were revealed, which represented the species Streptomyces griseus, S. citreofluorescens, and S. viridovulgaris subsp. albomarinus. These weakly differentiated variants id not produce A-factor and behaved as its recipients, responding by changes in their morphological characteristics at a concentration of this regulator in the medium of 0.01 microgram/ml and higher. The original collection strains in whose populations the variants were selected produced substances of the A-factor group. The A-factor-dependent variants differed in the level of the regulator required for maximal expression of the morphological characteristics were shown: it was necessary to introduce the A-factor at a concentration of 1 microgram/ml for S. citreofluorescens and S. viridovulgaris subsp. albomarinus and at 10 micrograms/ml for S. griseus.
authors.affiliation: Gauze Institute of New Antibiotics, Russian Academy of Medical Sciences, ul. Bol'shaya Pirogovskaya 11, Moscow, Russia. instna@online.ru
authors.forename: O V
authors.initials: OV
authors.lastname: Efremenkova
authors.forename: V D
authors.initials: VD
authors.lastname: Gruzina
authors.forename: I G
authors.initials: IG
authors.lastname: Sumarukova
authors.forename: V D
authors.initials: VD
authors.lastname: Kuznetsov
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006133:Growth Substances / Q000378:metabolism / Q000494:pharmacology*; D013045:Species Specificity; D013306:Streptomycetaceae / Q000187:drug effects* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D006133:Growth Substances; C025035:A-factor (Streptomyces); D015107:4-Butyrolactone