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The type and level of resistance of Bac. licheniformis 1001 to the antibiotic produced by it, i. e. bacitracin and the effect of bacitracin and some other drugs on the culture variation with respect to the feature of the antibiotic production were studied. It was found that strain 1001 possessed an inducible resistance to its own antibiotic. In addition, a cross inducible resistance to bacitracin and penicillin was observed. The mutations of the resistance to bacitracin, as well as streptomycin, rifampicin and sulfaethidole had no effect on bacitracin production by strain 1001.

Production of bacitracin by Bac. licheniformis 1001 and its spontaneous autolysin resistant variants was studied. It was found that the antibiotic activity of some variants was 1.5--2 times higher than that of the initial strain. No differences in the activity of serine exoprotease in the initial strain and resistant variants were observed. The latter variants lost their resistance to autolysis in 2--3 subcultures on solid and liquid nutrient media. their antibiotic activity in these cases decreased to the control level. The study indicates that there is a phenomenologic relation between the autolytic and antibiotic activities of Bac. licheniformis. The nature of the relation is not known yet. Possibly, it is due to changes in the specific metabolic steps connected with regulation of bacitracin synthesis.

The bacitracin production levels in some auxotrophic mutants of a highly active strain 1001 and strain ATCC 10716 were studied. It was shown that auxotrophic mutations in the genomes of the above strains resulted in decreasing of bacitracin production. In double auxotrophic mutants the synthesis of bacitracin was sometimes at the level of the initial strain. It was found that various amino acids and bases added to the cultivation medium in concentrations of 1 to 10 mg/ml either increased or decreased the production of bacitracin. It is suggested that some amino acids may play the decisive role in the control of the bacitracin synthesis.