title: Radiation-sensitive mutant of hypertoxinogenic strain 569B of Vibrio cholerae.
abstract: A radiation-sensitive mutant of the hypertoxinogenic strain 569B of Vibrio cholerae was isolated and characterized. The mutant, designated V. cholerae 569Bs, lacks both excision- and medium-dependent dark-repair mechanisms of UV-induced DNA damage while retaining the wild-type photoreactivating capability. Analysis of the UV-irradiated cell DNA by velocity sedimentation in alkaline sucrose gradient suggests that UV-induced pyrimidine dimers may not be incised in these cells. In contrast to the wild-type cells, the mutant cell DNA was degraded after treatment with nalidixic acid. The mutant cells failed to produce any detectable amount of cholera toxin as measured by ileal-loop assay.
mesh_terms: D001435:Bacteriophages / Q000528:radiation effects; D002772:Cholera Toxin / Q000096:biosynthesis; D004260:DNA Repair; D004279:DNA, Viral / Q000528:radiation effects; D009154:Mutation; D014466:Ultraviolet Rays; D014734:Vibrio cholerae / Q000235:genetics* / Q000528:radiation effects
chemical_list: D004279:DNA, Viral; D002772:Cholera Toxin