Multiple effects induced by unstable mutation in Streptomyces lavendulae.

Arg mutants, isolated from Streptomyces lavendulae at unusually high frequencies, showed several phenotypic characteristics. The characteristics common to all arg mutants include: (1) repression of beta-lactamase production, (2) inhibition of aerial mycelium formation, (3) development of acid pH, (4) low saturation density of growth in liquid culture, (5) a decrease in antibiotic production, (6) an increase in sensitivity to benzylpenicillin and (7) a decrease in production of pigment. These results suggest that the arg mutation concomitantly caused the depression of secondary metabolism in S. lavendulae.