Action of streptomycin on the growth of Streptomyces griseus.

Abstract

A streptomycin-producing culture of Streptomyces griseus was sensitive to streptomycin, but inhibition was temporary, and cultures supplemented with the antibiotic up to 100 μg/ml grew after a lag. Streptomycin tolerance developed, not by inactivation of the antibiotic but by selection of resistant variants in the natural population. Addition of streptomycin to growing cultures caused a drastic reduction in protein synthesis and an accumulation of "stuck" (70 S) ribosomes within the mycelium. Although the effect on protein synthesis could not be confirmed in vitro because cell extracts from S. griseus contained an inhibitor of polyuridylic-acid-directed polymerization of L-phenylalanine, it is concluded that streptomycin prevents the growth of this organism by a mechanism similar to that observed with other bacteria and that the tolerance of producing cultures cannot be attributed to the presence of streptomycin-resistant ribosomes.