title: Unstable mutation of beta-lactamase production in Streptomyces lavendulae.
abstract: Streptomyces lavendulae S55-B1 gave two distinct variants at an unusual high frequency: one is a beta-lactamase-nonproducing variant and the other is an Arg- variant. All of the Arg- variants concomitantly had no, or only very low, beta-lactamase activity and were unable to form aerial mycelia or spores. There was no significant linkage between the beta-lactamase activity and the other nutritional requirement which was analyzed. Two of the Arg- variants spontaneously gave Arg+ revertants at a very low frequency. The revertants, however, did not recover the beta-lactamase activity. It is suggested that the beta-lactamase gene may be capable of transposition with inactivation of the arg gene occurring frequently by insertion of the transposed element. Covalently closed circular deoxyribonucleic acid from S55-B1 was not detected by either cesium chloride-ethidium bromide buoyant density centrifugation or agarose gel electrophoresis.
mesh_terms: D000167:Acriflavine / Q000494:pharmacology; D001120:Arginine / Q000378:metabolism; D004270:DNA, Circular / Q000096:biosynthesis; D004271:DNA, Fungal / Q000096:biosynthesis; D009154:Mutation; D010641:Phenotype; D013172:Spores, Fungal; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D013997:Time Factors; D001618:beta-Lactamases / Q000096:biosynthesis*
chemical_list: D004270:DNA, Circular; D004271:DNA, Fungal; D000167:Acriflavine; D001120:Arginine; D001618:beta-Lactamases