title: The effect of R plasmids and antibiotics on the UV recovery of Escherichia coli strain B.
abstract: A R-plasmid-containing fil mutant of Escherichia coli strain B, when exposed to chloramphenical (CMP) plus streptomycin (Sm) after irradiation, achieved 100% ultraviolet (UV) recovery from doses that otherwise kill over 90% of the cells. UV-induced filament cells with R plasmids are very UV sensitive regardless of the treatment after the filament-inducing irradiation. The exposure to CMP and Sm can be delayed after irradiation and still rescue filament cells from UV death even when grown on antibiotic-free agar. Development of UV-induced filament cells in CMP-Sm liquid medium increases the number of irradiated cells that will recover the ability to divide even when transferred to antibiotic-free agar soon after irradiation. The results suggest that the recovery of cell division by UV-induced filaments with R plasmids can be accomplished by contact with antibiotics even after extensive "unbalanced growth" or by growing in liquid medium throughout a critical period following irradiation.
mesh_terms: D002455:Cell Division / Q000187:drug effects; D002701:Chloramphenicol / Q000494:pharmacology*; D003470:Culture Media; D004260:DNA Repair; D004926:Escherichia coli / Q000528:radiation effects*; D011815:R Factors; D013307:Streptomycin / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D003470:Culture Media; D002701:Chloramphenicol; D013307:Streptomycin