Abstract
Cells of E. coli that are recA+ and lex+ show a phenomenon of induced radioresistance. A preexposure to ultraviolet light, or ionizing radiation followed by incubation to allow protein synthesis, followed by treatment with rifampin to prevent further induction, renders the cells resistant to further doses of radiation. When this is attempted with lambda lysogens of the same strains, no radioresistance is seen, even though the preexposure is too small to induce lambda itself. If the lysogens are ind-, namely lambda C1857, about the normal radioresistance can be developed by pretreatment. These findings suggest that the lambda repressors can bind to single-strand breaks caused by the inducing agent and can modify the course of induction.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- JAGGER J. A small and inexpensive ultraviolet dose-rate meter useful in biological experiements. Radiat Res. 1961 Apr;14:394–403. [PubMed] [Google Scholar]
- Little J. W., Kleid D. G. Escherichia coli protein X is the recA gene product. J Biol Chem. 1977 Sep 25;252(18):6251–6252. [PubMed] [Google Scholar]
- Monk M., Peacey M., Gross J. D. Repair of damage induced by ultraviolet light in DNA polymerase-defective Escherichia coli cells. J Mol Biol. 1971 Jun 14;58(2):623–630. doi: 10.1016/0022-2836(71)90376-7. [DOI] [PubMed] [Google Scholar]
- Pollard E. C., Achey P. M. Induction of radioresistance in Escherichia coli. Biophys J. 1975 Nov;15(11):1141–1154. doi: 10.1016/S0006-3495(75)85890-5. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith K. C., Martignoni K. D. Protection of Escherichia coli cells against the lethal effects of ultraviolet and x irradiation by prior x irradiation: a genetic and physiological study. Photochem Photobiol. 1976 Dec;24(6):515–523. doi: 10.1111/j.1751-1097.1976.tb06868.x. [DOI] [PubMed] [Google Scholar]
- Sussman R., Zeev H. B. Proposed mechanism of bacteriophage lambda induction: acquisition of binding sites for lambda repressor by DNA of the host. Proc Natl Acad Sci U S A. 1975 May;72(5):1973–1976. doi: 10.1073/pnas.72.5.1973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Witkin E. M. Ultraviolet mutagenesis and inducible DNA repair in Escherichia coli. Bacteriol Rev. 1976 Dec;40(4):869–907. doi: 10.1128/br.40.4.869-907.1976. [DOI] [PMC free article] [PubMed] [Google Scholar]