RT Journal Article SR Electronic(1) A1 Volff, Jean-nicolas A1 Vandewiele, Dominique A1 Simonet, Jean-marc A1 Decaris, BernardYR 1993 T1 Stimulation of genetic instability in Streptomyces ambofaciens ATCC 23877 by antibiotics that interact with DNA gyrase JF Microbiology, VO 139 IS 11 SP 2551 OP 2558 DO https://doi.org/10.1099/00221287-139-11-2551 PB Microbiology Society, SN 1465-2080, AB In wild-type Streptomyces ambofaciens ATCC 23877, pigment-defective (Pig−) mutants arise at a frequency of about 0·5%; this genetic instability is related to genomic rearrangements such as deletions and/or amplifications of DNA sequences. On media containing oxolinic acid and novobiocin, which interact with the A and B subunits of DNA gyrase, respectively, the frequency of variants increased dramatically. The Pig− mutant frequency was increased to almost 100% on a medium containing oxolinic acid at a concentration allowing 55% survival. On solid medium containing either oxolinic acid or novobiocin at subinhibitory concentrations, most colonies exhibited a ‘patchwork’ phenotype, characterized by the presence of numerous Pig− sectors. Similar phenomena were not observed on media containing the transcriptional inhibitor rifampicin or the translational inhibitor streptomycin. Many of the Pig− mutants exhibited a pleiotropic phenotype and were affected in aerial mycelium formation, colony growth and/or prototrophy. Moreover, the same kinds of rearrangements (deletions and/or amplifications of DNA sequences) were found in both induced and spontaneous Pig− mutants. The results suggest either that DNA gyrase is directly involved in genetic instability or that an SOS-like system is implicated., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/00221287-139-11-2551