Plasmid variability in the istamycin producing strains of Streptomyces tenjimariensis.

Abstract
Three strains of istamycin-producing S. tenjimariensis were isolated over a period of time from soils at the same location and have 3 different types of plasmid profiles. Protoplast fusion between 2 of these strains provided a clone harboring a smaller plasmid not present in the parent strains. None of the plasmids had restriction sites of EcoR I and Hind III. Most of the plasmids had 1 or 2 restriction sites for BamHI, BclI, BglII, KpnI, PstI and PvuII and > 2 restriction sites for SalI and Sst. Plasmid restriction maps and southern hybridization experiments revealed that pST2, pST12 and pST22 were identical, as were pST10 and pST20; pSTl*, PST1, pST11 and pST21 were related to each other.