title: [The need for protein synthesis in UV-irradiated Escherichia coli cells for fixation of induced Str mutations].
abstract: The kinetics of accumulation of fixed Str mutations was determined during incubation in nutritional medium of Escherichia coli WP2 irradiated with 6.8 J/m2 either at log growth phase or after completion of DNA replication. Those Str mutations which lost ability for photoreactivation (fixation I) or susceptibility to antimutagenic activity of mfd-type (fixation II) were considered as fixed mutations. It was shown that both fixations occurred synchronously, starting in about 10 min after irradiation and being over in 40-50 min. In cells irradiated after completion of replication, fixation depended on protein synthesis de novo: chloramphenicol added to irradiated culture blocked fixation. An attempt to study the effect of chloramphenicol on fixation in a culture irradiated at the log phase failed, because of high lethal action of the antibiotic on such cells. Fixation could proceed in the presence of acriflavine. Possible mechanisms for fixation of Str mutations are discussed in connection with the fact of its dependence on protein synthesis.
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis*; D002701:Chloramphenicol / Q000494:pharmacology; D004260:DNA Repair / Q000528:radiation effects; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D009154:Mutation; D013489:Suppression, Genetic; D014466:Ultraviolet Rays
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D002701:Chloramphenicol
vernacular_title: Neobkhodimost' sinteza belka v UF-obluchennykh kletkakh Escherichia coli dlia fiksatsii indutsirovannykh mutatsiĭ Str.