Induction of radioresistance in Escherichia coli

Pollard, Ernest C.; Achey, Phillip M.

doi:10.1016/s0006-3495(75)85890-5

Cited by 35 publications

(3 citation statements)

References 21 publications

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“…This is radioresistance and its induction has also been noted for microorganisms which were previously irradiated (e.g., Pollard andAchey 1975, Smith 1973, as quoted by Luckey 1982).…”

Section: Positive Effects Of Radiationmentioning

confidence: 71%

Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

Meike¹,

Stroes-Gascoyne²

2000

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“…This is radioresistance and its induction has also been noted for microorganisms which were previously irradiated (e.g., Pollard andAchey 1975, Smith 1973, as quoted by Luckey 1982).…”

Section: Positive Effects Of Radiationmentioning

confidence: 71%

Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

Meike¹,

Stroes-Gascoyne²

2000

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“…In this paper, we show that such repair is not carried out by enzymes present in normal cells but requires the synthesis of proteins induced by damage to intracellular DNA. Our experiments were suggested by those of Pollard and his associates (4,5). They found that the colony-forming ability of E. coli cells was sensitized to x-rays by treatment with rifampicin just before irradiation; however, cells exposed to UV light and incubated for 45 min before addition of rifampicin had regained their resistance to x-rays.…”

mentioning

confidence: 88%

Repair of DNA double-strand breaks in Escherichia coli cells requires synthesis of proteins that can be induced by UV light.

Krasin¹,

Hutchinson²

1981

Proc. Natl. Acad. Sci. U.S.A.

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The repair of DNA double-strand breaks in Escherichia coli cells irradiated with y rays occurs only after new proteins are synthesized in response to damage introduced in the genome DNA. One protein whose synthesis is thus induced is the recA protein, and previous work has shown that recA-cells do not repair double-strand breaks. However, inducing recA protein by treating cells with nalidixic acid does not induce repair of doublestrand breaks, so this repair requires more than the presence of the recA protein. In Escherichia coli cells, repair of DNA double-strand breaks requires an active recA gene and the presence of another DNA duplex that has the same base sequence as the broken double helix (3); normally growing K-12 strains can repair doublestrand breaks because they have four or five genomes per cell.In this paper, we show that such repair is not carried out by enzymes present in normal cells but requires the synthesis of proteins induced by damage to intracellular DNA.Our experiments were suggested by those of Pollard and his associates (4, 5). They found that the colony-forming ability of E. coli cells was sensitized to x-rays by treatment with rifampicin just before irradiation; however, cells exposed to UV light and incubated for 45 min before addition of rifampicin had regained their resistance to x-rays. Similar results have been reported by Smith and Martignoni (6). This suggests that the repair of some lesion, such as a DNA double-strand break, could be one ofthose processes that Radman (7) and Witkin (8) have classified as coordinate responses to DNA damage in E. coli recA+ lexA+ cells: mutagenesis, Weigle mutagenesis and Weigle reactivation (the increase in mutagenesis and plaque-forming ability of UV-irradiated A phage when the host c~ells are also irradiated), filamentation, induction ofprophage, synthesis of recA protein, and others.Kenyon and Walker (9) have evidence that damage to the DNA in E. coli cells induces increased transcription at several specific loci on the chromosome; one site is known to be close to the uvrA locus coding for one component of an endonuclease that incises DNA next to a pyrimidine cyclobutane dimer. The increased transcription occurs only in cells that have recA and lexA functions.Little et al. (10) have isolated the lexA protein and shown that it both represses the synthesis of recA protein and is specifically cleaved by the recA protease. Presumably, damage to intracellular DNA activates the recA protease and causes it to cleave the lexA protein in the same way that recA protease cleaves the A repressor (11)(12)(13)(14). A reduced concentration of lexA protein leads in turn to increased synthesis of recA protein. It is not known whether the lexA protein is also a repressor for any of the other sites of transcription activated by DNA damage. Kenyon and Walker (9) state that the various loci differ widely in their basal levels, lag times for expression, and final induced levels, which suggests they are not all controlled in the same way.The other loci are...

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“…Cells of E. coli that are neither recAor lex-show an induced radioresistance (IRR) when pretreated by ultraviolet light (UV), ionizing radiation, or nalidixic acid as inducing agents (1,2).…”

Section: Introductionmentioning

confidence: 99%

Induced radioresistance in four strains of Escherichia coli, two with lambda lysogens

Pollard¹

1978

Biophysical Journal

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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.

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Induction of radioresistance in Escherichia coli

Cited by 35 publications

References 21 publications

Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

Review of Microbial Responses to Abiotic Environmental Factors in the Context of the Proposed Yucca Mountain Repository

Repair of DNA double-strand breaks in Escherichia coli cells requires synthesis of proteins that can be induced by UV light.

Induced radioresistance in four strains of Escherichia coli, two with lambda lysogens

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