Plasmid variability in the istamycin producing strains of Streptomyces tenjimariensis.

Three strains of istamycin-producing Streptomyces tenjimariensis were isolated over a period of time from soils at the same location and were found to have three different types of plasmid profiles. Protoplast fusion between two of these strains provided a clone harboring a smaller plasmid not present in the parent strains. None of the plasmids had restriction sites for EcoR I and Hind III. Most of the plasmids had one or two restriction sites for BamH I, Bcl I, Bgl II, Kpn I, Pst I and Pvu II, and more than two restriction sites for Sal I and Sst II. Plasmid restriction maps and Southern hybridization experiments revealed that pST2, pST12 and pST22 were identical, as were pST10 and pST20. In addition, it was revealed that pST1, pST1, pST11 and pST21 were related to each other.