Abstract
Plasmid profiles were used to screen streptomycetes for production of new antibiotics. Among about 100 strains isolated from sea muds, an isolate designated SS-939 was revealed to harbor several plasmids of different sizes and to produce istamycins, new aminoglycoside antibiotics. Based on the characteristics of the strain, a new Streptomyces species is proposed: S. tenjimariensis.