title: [Role of gramicidin S in the sporulation of the R+ and R- variants of Bacillus brevis var. G.-B].
abstract: The effect of gramicidin S added to the cultivation medium on sporulation of the gramicidin S-producing P+ variant and gramicidin S-nonproducing P- variant of Bacillus brevis var. G.-B. was studied. Gramicidin S added to the synthetic medium with glucose in an amount of 30 and 100 microgram/ml 4 and 7 hours after inoculation with the vegetative cells of R- variant had no effect on the growth of the culture but retarded its sporulation. When gramicidin S was added in an amount of 100 microgram/ml 4 hours after inoculation, the sporulation rate of R- variant strongly decreased, rohile sporulation was not suppressed as it was noted before with respect to R+ variant. Active stimulation of Bacillus brevis var. G.-B. sporulation was observed after addition of gramicidin S 13 hours after development of R+ and R- variants without the antibiotic biosynthesis. Synthesis of gramicidin S by R+ strain was suppressed by the specific inhibitor beta-phenyl-beta-alanine. The amount of gramicidin S added to the medium during the sporulation process of R+ and R- variants decreased. On addition of 30 microgram/ml of the antibiotic it was practically not detectable when the culture showed the greatest number of the spores. Therefore, gramicidin S added to the medium is probably adsorbed by the cells of Bac. brevis var. G.-B. and affects sporulation of R- and R+ variants thus accelerating or retarding this process depending on the cultivation conditions.
mesh_terms: D001407:Bacillus / Q000187:drug effects* / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D014644:Genetic Variation / Q000187:drug effects*; D006096:Gramicidin / Q000494:pharmacology*; D013171:Spores, Bacterial / Q000187:drug effects / Q000502:physiology; D013997:Time Factors
chemical_list: D006096:Gramicidin
vernacular_title: Rol' gramitsidina S v sporoobrazovanii R+ i R- variantov Bacillus brevis var. G.-B.