Skip to main content
NCBI home page
Proceedings of the National Academy of Sciences of the United States of America logoLink to Proceedings of the National Academy of Sciences of the United States of America
. 1975 Jan;72(1):167–171. doi: 10.1073/pnas.72.1.167

DNA strand breaks measured within 100 milliseconds of irradiation of Escherichia coli by 4 MeV electrons.

I Johansen, T Brustad, W D Rupp
PMCID: PMC432263  PMID: 1090932

Abstract

A method was developed in which E. coli cells were irradiated with four MeV electrons and transferred to alkaline detergent within a fraction of a second. This technique minimizes the amount of repair of radiation damage before analysis without the necessity of using physical or chemical treatments to inhibit repair and alter the physiological condition of the cells. The yield of DNA strans breaks formed in covalent circular superhelical lambda DNA molecules superinfecting E. coli lysogens was about 4-fold greater when the cells were irradiated in oxygen than when they were irradiated under nitrogen anoxia. The same yields were obtained in phosphate buffer at 3 degrees and 22 degrees as well as in growth medium at 37 degrees, and the yields were not altered by the polA1 mutation. When E. coli lysogenic cells superinfected with lambda were irradiated with doses sufficient to introduce at least seven breaks in the phage DNA, the chromosomal DNA and the superinfecting phage DNA sedimented similarly in alkaline sucrose gradients, indicating that both DNAs were broken to a similar extent during irradiation. However, the yield of breaks calculated for chromosomal DNA in similar experiments was greater than the yield calculated from the first break introduced into covalent circular lambda DNA molecules. These apparently contradictory results are explicable either if the initial break in a superhelical molecule occurs with an efficiency different from that for subsequent breaks, or if the pulsed electron radiation produces a high proportion of double-strand breaks.

Full text

PDF
167

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Beerman T. A., Lebowitz J. Further analysis of the altered secondary structure of superhelical DNA. Sensitivity to methylmercuric hydroxide a chemical probe for unpaired bases. J Mol Biol. 1973 Sep 25;79(3):451–470. doi: 10.1016/0022-2836(73)90398-7. [DOI] [PubMed] [Google Scholar]
  2. De Lucia P., Cairns J. Isolation of an E. coli strain with a mutation affecting DNA polymerase. Nature. 1969 Dec 20;224(5225):1164–1166. doi: 10.1038/2241164a0. [DOI] [PubMed] [Google Scholar]
  3. Dean C. J., Ormerod M. G., Serianni R. W., Alexander P. DNA strand breakage in cells irradiated with x-rays. Nature. 1969 Jun 14;222(5198):1042–1044. doi: 10.1038/2221042a0. [DOI] [PubMed] [Google Scholar]
  4. Freifelder D. Molecular weights of coliphages and coliphage DNA. IV. Molecular weights of DNA from bacteriophages T4, T5 and T7 and the general problem of determination of M. J Mol Biol. 1970 Dec 28;54(3):567–577. doi: 10.1016/0022-2836(70)90127-0. [DOI] [PubMed] [Google Scholar]
  5. Gross J., Gross M. Genetic analysis of an E. coli strain with a mutation affecting DNA polymerase. Nature. 1969 Dec 20;224(5225):1166–1168. doi: 10.1038/2241166a0. [DOI] [PubMed] [Google Scholar]
  6. 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. 1966 Jun;53(6):1119–1136. doi: 10.1093/genetics/53.6.1119. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Johansen I., Gulbrandsen R., Pettersen R. Effectiveness of oxygen in promoting x-ray-induced single-strand breaks in circular phage lambda DNA and killing of radiation-sensitive mutants of Escherichia coli. Radiat Res. 1974 Jun;58(3):384–397. [PubMed] [Google Scholar]
  8. Johansen I., Gurvin I., Rupp W. D. The formation of single-strand breaks in intracellular DNA by x-rays. Radiat Res. 1971 Dec;48(3):599–612. [PubMed] [Google Scholar]
  9. Modorich P., Lehman I. R. Deoxyribonucleic acid ligase. A steady state kinetic analysis of the reaction catalyzed by the enzyme from Escherichia coli. J Biol Chem. 1973 Nov 10;248(21):7502–7511. [PubMed] [Google Scholar]
  10. Olivera B. M., Lehman I. R. Enzymic joining of polynucleotides. 3. The polydeoxyadenylate-polydeoxythymidylate homopolymer pair. J Mol Biol. 1968 Sep 14;36(2):261–274. doi: 10.1016/0022-2836(68)90380-x. [DOI] [PubMed] [Google Scholar]
  11. Paterson M. C., Roozen K. J., Setlow R. B. -Ray-induced chain breaks and alkali-labile bonds in lambda d upsilon DNA of Escherichia coli minicells irradiated under aerobic and anoxic conditions. Int J Radiat Biol Relat Stud Phys Chem Med. 1973 May;23(5):495–508. doi: 10.1080/09553007314550571. [DOI] [PubMed] [Google Scholar]
  12. Rupp W. D., Howard-Flanders P. Discontinuities in the DNA synthesized in an excision-defective strain of Escherichia coli following ultraviolet irradiation. J Mol Biol. 1968 Jan 28;31(2):291–304. doi: 10.1016/0022-2836(68)90445-2. [DOI] [PubMed] [Google Scholar]
  13. Setlow R. B., Setlow J. K. Effects of radiation on polynucleotides. Annu Rev Biophys Bioeng. 1972;1:293–346. doi: 10.1146/annurev.bb.01.060172.001453. [DOI] [PubMed] [Google Scholar]
  14. Town C. D., Smith K. C., Kaplan H. S. DNA polymerase required for rapid repair of x-ray--induced DNA strand breaks in vivo. Science. 1971 May 21;172(3985):851–854. doi: 10.1126/science.172.3985.851. [DOI] [PubMed] [Google Scholar]
  15. Town C. D., Smith K. C., Kaplan H. S. Influence of ultrafast repair processes (independent of DNA polymerase I) on the yield of DNA single-strand breaks in Escherichia coli K-12 x-irradiated in the presence of or absence of oxygen. Radiat Res. 1972 Oct;52(1):99–114. [PubMed] [Google Scholar]
  16. Town C. D., Smith K. C., Kaplan H. S. The rapair of DNA single-strand breaks in E. coli K-12 x-irradiated in the presence or absence of oxygen; the influence of repair on cell survival. Radiat Res. 1973 Aug;55(2):334–345. [PubMed] [Google Scholar]

Articles from Proceedings of the National Academy of Sciences of the United States of America are provided here courtesy of National Academy of Sciences

RESOURCES