title: Induction of streptomycin-inactivating enzyme by A-factor in Streptomyces griseus.
abstract: The effect of A-factor on streptomycin resistance and productivity in Streptomyces griseus and S. bikiniensis was studied using A-factor-negative mutants. Resistance of several of these mutants was markedly increased by adding A-factor to the growing medium, as also was their streptomycin productivity. The A-factor induced resistance was due to inactivation by streptomycin-6-phosphotransferase, and enzyme synthesis in these mutants was completely dependent on the presence of A-factor. In the case of S. griseus 2247 where streptomycin productivity was independent of A-factor, resistance and synthesis of the inactivating enzyme were also independent of A-factor. A-Factor-negative mutants of S. griseus showed a decreased level of NADP-glycohydrolase and an increased level of several NADP-linked dehydrogenases, but these enzymes did not return to parental levels in cultures supplemented with A-factor. A-Factor seems to regulate streptomycin biosynthesis, not through an indirect metabolic sequence involving these enzymes but, more likely, by directly stimulating synthesis of enzyme(s) in the biosynthetic pathway.
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives; D004352:Drug Resistance, Microbial; D004790:Enzyme Induction / Q000187:drug effects; D006133:Growth Substances / Q000494:pharmacology*; D009249:NADP / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000096:biosynthesis*; D017853:Phosphotransferases (Alcohol Group Acceptor); D013302:Streptomyces / Q000201:enzymology; D013305:Streptomyces griseus / Q000201:enzymology*; D013307:Streptomycin / Q000378:metabolism*; D013997:Time Factors
chemical_list: D006133:Growth Substances; C025035:A-factor (Streptomyces); D009249:NADP; D010770:Phosphotransferases; D017853:Phosphotransferases (Alcohol Group Acceptor); C022680:streptomycin 6-kinase; D015107:4-Butyrolactone; D013307:Streptomycin