title: Self-resistance of the nourseothricin-producing strain Streptomyces noursei.
abstract: The nourseothricin producer Streptomyces noursei is resistant to its own antibiotic in submerged as well as in surface culture. The strain shows no cross-resistance to miscoding inducing aminoglycoside antibiotics. Cell free extracts of Streptomyces noursei inactivate nourseothricin by enzymatic acetylation. The pattern of cross-resistance of Streptomyces noursei correlates well with the substrate specificity of the nourseothricin acetyltransferase. Furthermore, the acetyltransferase activity parallels the resistance level in nourseothricin-producing strains and nonproducing mutants. The results suggest that the nourseothricin acetyltransferase is important in the self-defence strategy of the nourseothricin-producing strain.
mesh_terms: D000123:Acetyltransferases / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D013302:Streptomyces / Q000187:drug effects* / Q000201:enzymology; D013309:Streptothricins / Q000378:metabolism / Q000494:pharmacology*; D013379:Substrate Specificity
chemical_list: D000900:Anti-Bacterial Agents; D013309:Streptothricins; D000123:Acetyltransferases; C050473:nourseothricin acetyltransferase