MOLECULAR-GENETIC STUDY OF STREPTOMYCES-V IRGINIAE, THE PRODUCER OF VIRGINIAMYCIN

The level and the character of the Streptomyces virginiae virginiamyci n-producing strain's resistance to self-produced antibiotic and a numb er of antibiotics from different groups were determined. S. virginiae was shown to display constitutive and inducible resistance to self-pro duced antibiotic. The phenomenon of cross-inducible resistance of the strain to virginiamycin and the antibiotics erythromycin, oleandomycin , and thiostrepton was demonstrated. The pTO1 and pVGTB24 plasmids wer e introduced into the strain by the method of intergeneric conjugation with Escherichia coli. Site-specific integration of the pTO1 vector i nto the S. virginiae chromosomal attB site without disturbance of grow th, differentiation, and productivity of the strain was shown, The mul ticopy autonomously replicating plasmids pIJ699, pIJ702, pWOR109, and the integrative pZAT22 plasmid were introduced into the strain via ele ctrotransformation of germinating spores. The efficiency of transforma tion was 1-5 x 10(3) transformants per 1 mu g DNA. The stable inherita nce of the plasmids in S. virginiae without structural rearrangements was shown. These results allow the use of these plasmids to clone gene s into S. virginiae.