Anthracycline metabolites from Streptomyces violaceus A262. I. Isolation of antibiotic-blocked mutants from Streptomyces violaceus A262.

Five mutant (or variant) strains producing new anthracycline antibiotics were derived from Streptomyces violaceus A262 by mutagenesis treatment. Strain SE1-625 showed a limited production of three known beta-rhodomycinone diglycosides while the parent strain produced numerous unidentified beta-rhodomycinone glycosides. Strain SU2-730 was an antibiotic-blocked mutant which produced only epsilon-rhodomycinone glycosides (named epelmycins). Strains SC-7 and SE2-2385 were variants which produced alpha-citromycinone glycosides (named yellamycins) and beta-isorhodomycinone glycosides (named obelmycins), respectively. Strain SE2-2385-A1 produced alpha 2-rhodomycinone glycosides (named alldimycins). Glycosidation-less mutants which accumulated only aglycone were also obtained. Isolation of these mutants or variants and preliminary identification of their anthracycline products are described.