Survival, mutation and capacity to repair single-strand DNA breaks after gamma irradiation in different Exr− strains of Escherichia coli
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Strains of Escherichia coli K-12 and B/r made by transduction of the exrA allele from a Bs-2 derivative have been compared with Exr(W)− strains derived from Bs-1 and Bs-2 by mutation (E.M. Witkin, 1967). Both transduced exrA and Exr(W)− strains were almost unmutable by gamma radiation, but the former class were as sensitive to gamma radiation as recA strains and, like them, were unable to repair single-strand DNA breaks as detected by the McGrath-Williams technique. In contrast the Exr(W)−strains were as resistant to gammaradiation as Exr(W)+ strains derived from them and were equally efficient in repairing single-strand breaks. The existence of Exr(W)−strains suggests that the mutagenicity of single-strand breaks may depend entirely on the way in which they are repaired. The properties of the (Exr(W)−strains cannot be ascribed solely to the transducable exrA allele.
A large effect of diffuse daylight in lowering the molecular weight of DNA on alkaline sucrose gradients is described which, unless prevented, may lead to erroneous results in such experiments.
- Boyle, J. M., Symonds, N.: Radiation sensitive mutants of T4D.1. T4y: A new radiation sensitive mutant; effect of the mutation on radiation survival, growth and recombination. Mutation Res. 8, 431–439 (1969).
- Bridges, B. A.: Simple bacterial systems for detecting mutagenic agents. Lab. Pract. 21, 413–419 (1972).
- Bridges, B. A., Ashwood-Smith, M. J., Munson, R. J.: Correlation of bacterial sensitivities to ionizing radiation and mild heating. J. gen. Microbiol. 58, 115–124 (1969).
- Bridges, B. A., Law, J., Munson, R. J.: Mutagenesis in Escherichia coli. II Evidence for a common pathway for mutagenesis by ultraviolet light, ionizing radiation and thymine deprivation. Molec. gen. Genet. 103, 266–273 (1968).
- Bridges, B. A., Mottershead, R. P.: Gamma ray mutagenesis in a strain of Escherichia coli deficient in DNA polymerase I. Heredity, in the press (1972).
- Bridges, B. A., Mottershead, R. P., Rothwell, M. A., Green, M. H. L.: Repair-deficient bacterial strains suitable for mutagenicity screening: tests with the fungicide captan. Chem. Biol. Interactions 5, 77–84 (1972).
- Carrier, W. L., Setlow, R. B.: Paper strip method for assaying gradient fractions containing radioactive macromolecules. Analyt. Biochem. 43, 427–432 (1971).
- Davis, B. D., Mingioli, E. S.: Mutants of Escherichia coli requiring methionine or vitamin B12. J. Bact. 60, 17–28 (1950).
- Donch, J., Chung, Y. S., Greenberg, J.: Locus for radiation resistance in Escherichia coli strain B/r. Genetics 61, 363–370 (1969).
- Donch, J., Greenberg, J.: Loci of radiation sensitivity in Bs strains of Escherichia coli. Genet. Res. (Camb.) 11, 183–191 (1968).
- Elkind, M. M.: Sedimentation of DNA released from Chinese hamster cells. Biophys. J. 11, 502–520 (1971).
- Green, M. H. L., Rothwell, M. A., Bridges, B. A.: Mutation to prototrophy in Escherichia coli K-12: effect of broth on UV-induced mutation in strain AB1157 and four excisiondeficient mutants. Mutation Res. 16, 225–234 (1972).
- Greenberg, J.: A locus for radiation sensitivity in Escherichia coli Bs-2. Genetics 50, 639–648 (1964).
- Greenberg, J.: Loci for radiation sensitivity in Escherichia coli strain Bs-1. Genetics 55, 193–201 (1967).
- Hill, R. F., Simson, E.: A study of radiosensitive and radioresistant mutants of Escherichia coli strain B. J. gen. Microbiol. 35, 105–114 (1961).
- Howard-Flanders, P., Boyce, R. P., Theriot, L.: Three loci in Escherichia coli K-12 that control the excision of pyrimidine dimers and certain other mutagen products from DNA. Genetics 53, 1119–1136 (1966).
- Howard-Flanders, P., Theriot, L.: Mutants of Escherichia coli K-12 defective in DNA repair and in genetic recombination. Genetics 53, 1137–1150 (1966).
- Kapp, D. S., Smith, K. C.: Repair of radiation-induced damage in Escherichia coli. II Effect of rec and uvr mutations on radiosensitivity, and repair of X-ray induced single-strand breaks in deoxyribonucleic acid. J. Bact. 103, 49–54 (1970).
- Kondo, S.: Mutagenicity versus radiosensitivity in Escherichia coli. Proc. 12th Intern. Congr. Genetics 2, 126–127 (1968).
- Mattern, I. E., Zwenk, H., Rörsch, A.: The genetic constitution of the radiation sensitive mutant Escherichia coli Bs-1 Mutation Res. 3, 374–380 (1966).
- McGrath, R. A., Williams, R. W.: Reconstruction in vivo of irradiated Escherichia coli deoxyribonucleic acid; the rejoining of broken pieces. Nature (Lond.) 212, 534–535 (1966).
- Miura, A., Tomizawa, J.: Studies on radiation-sensitive mutants of E. coli, III. Participation of the Rec system in induction of mutation by ultra-violet irradiation. Molec. gen. Genet. 103, 1–10 (1968).
- Town, C. D., Smith, K. C., Kaplan, H. C.: DNA polymerase required for the rapid rejoining of X-ray induced DNA strand breaks in vivo. Science 172, 851–853 (1971).
- Witkin, E. M.: Mutation-proof and mutation prone modes of survival in derivatives of Escherichia coli B differing in sensitivity to ultraviolet light. Brookhaven Symp. Biol. 20, 17–55 (1967).
- Survival, mutation and capacity to repair single-strand DNA breaks after gamma irradiation in different Exr− strains of Escherichia coli
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