Two small linear plasmids of Streptomyces jumonjinensis

Abstract

In a survey of plasmids in a variety of β-lactam antibiotic producing Streptomyces spp., two small linear plasmids (pSJL1 and pSJL2) of approximately 12 and 17.5 kb were detected within Streptomyces jumonjinensis NRRL 5741, in addition to the previously reported giant linear plasmids pSJL3 and pSJL4. Characterization of these plasmids by Southern hybridization indicated that no significant homology exists between the S. jumonjinensis plasmids and plasmids detected in other β-lactam antibiotic producing Streptomyces spp. Single and double restriction endonuclease digestions were performed to generate maps of the two plasmids. The plasmids pSJL1 and pSJL2 have copy numbers of 21–27 and 15–20, respectively.Key words: Streptomyces, linear plasmid, DNA hybridization, DNA homology.