Repair of X-ray damage to the DNA in Micrococcus radiodurans: the effect of 5-bromodeoxyuridine

Lett, J. T.; Caldwell, Ian C.; Little, Joseph W.

doi:10.1016/0022-2836(70)90053-7

Cited by 65 publications

(19 citation statements)

References 12 publications

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“…In the nonlethal-dose range the delay in DNA synthesis increases linearly with the dose and is longer than the time necessary for maximum DNA degradation to occur (351). In the lethal-dose range the delay in DNA synthesis rapidly reaches its maximum, while the time required for maximum DNA degradation continues to increase linearly (350) (Fig. 5).…”

Section: Dna Degradation In Irradiated D Radioduransmentioning

confidence: 96%

“…The direct repair of SSBs is further corroborated by the partial repair upon incubation in a nonnutrient buffer (160). The repair of SSBs in D. radiodurans can be monitored by using alkaline sucrose gradients (79,154,157,350). The repair of DSBs is more difficult than the damage that affects a single strand (SSB or base damage) and relies upon interchromosomal recombination (125,445,572,676).…”

Section: Radioduransmentioning

confidence: 96%

“…Sensitization by iodoacetamide may include the repression of DNA degradation through the inhibition of an enzyme that excises DNA from a DNA-membrane complex (643) (see "DNA Degradation in Irradiated D. radiodurans") and the inhibition of the DNA reassociation with the membranes (129). The incorporation of 5-bromouracil into DNA also sensitizes the cells to the effects of X-ray radiation (147) by inhibiting DNA degradation and removing the shoulder of the survival curve (350). Furthermore, the addition of 100 M manganese to the growth medium during early stationary phase perturbs Mn-redox cycling and increases the susceptibility of the cells to the lethal and mutagenic effects of UV and ionizing radiation, MMC, and MNNG due to glucose oxidation and an increase in oxidative stress (96,122,362).…”

Section: Ionizing Radiation Resistance Of D Radioduransmentioning

confidence: 99%

“…These parameters include the rate and the extent of DNA degradation (161, 350, 351) (Fig. 5, top), a delay in DNA synthesis (135,350,351,440) (Fig. 5, bottom), and the rate of DNA synthesis (350).…”

Section: Radioduransmentioning

confidence: 99%

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Oxidative Stress Resistance inDeinococcus radiodurans

Slade

Radman

2011

Microbiol Mol Biol Rev

660

639

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SUMMARY Deinococcus radiodurans is a robust bacterium best known for its capacity to repair massive DNA damage efficiently and accurately. It is extremely resistant to many DNA-damaging agents, including ionizing radiation and UV radiation (100 to 295 nm), desiccation, and mitomycin C, which induce oxidative damage not only to DNA but also to all cellular macromolecules via the production of reactive oxygen species. The extreme resilience of D. radiodurans to oxidative stress is imparted synergistically by an efficient protection of proteins against oxidative stress and an efficient DNA repair mechanism, enhanced by functional redundancies in both systems. D. radiodurans assets for the prevention of and recovery from oxidative stress are extensively reviewed here. Radiation- and desiccation-resistant bacteria such as D. radiodurans have substantially lower protein oxidation levels than do sensitive bacteria but have similar yields of DNA double-strand breaks. These findings challenge the concept of DNA as the primary target of radiation toxicity while advancing protein damage, and the protection of proteins against oxidative damage, as a new paradigm of radiation toxicity and survival. The protection of DNA repair and other proteins against oxidative damage is imparted by enzymatic and nonenzymatic antioxidant defense systems dominated by divalent manganese complexes. Given that oxidative stress caused by the accumulation of reactive oxygen species is associated with aging and cancer, a comprehensive outlook on D. radiodurans strategies of combating oxidative stress may open new avenues for antiaging and anticancer treatments. The study of the antioxidation protection in D. radiodurans is therefore of considerable potential interest for medicine and public health.

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Section: Dna Degradation In Irradiated D Radioduransmentioning

confidence: 96%

Section: Radioduransmentioning

confidence: 96%

Section: Ionizing Radiation Resistance Of D Radioduransmentioning

confidence: 99%

Section: Radioduransmentioning

confidence: 99%

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Oxidative Stress Resistance inDeinococcus radiodurans

Slade

Radman

2011

Microbiol Mol Biol Rev

660

639

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“…Degradation of DNA occurs (Stuy, 1960) and the immediate reduction in single-strand DNA molecular weight is followed by a recovery of the original high molecular weight (McGrath and Williams, 1966). In Micrococcus radiodurans, where survival values are very high, it has been proposed that at least two post X-ray DNA repair systems are operative, one involving DNA degradation and another involving repair of strand breaks (Lett, Caldwell, and Little, 1970). The fact that some UV-sensitive mutants are sensitive X-rays and some are not suggests that there is a partial sharing of repair machinery.…”

Section: Introductionmentioning

confidence: 99%

X-Irradiation sensitivity in Escherichia coli defective in DNA replication

Fangman

Russel

1971

Molec. Gen. Genet.

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A mutant of Escherichia coli with a temperature sensitive defect in DNA replication is sensitive to X-irradiation but not to UV-irradiation. After UV-irradiation, dark-repair processes--dimer excision, DNA breakdown, repair synthesis and DNA strand joining--appear normal at the restrictive temperature. After X-irradiation, DNA degradation exceeds that in the wild type, and irradiation-dependent DNA synthesis does not occur. Single-strand breaks introduced into the DNA by the irradiation are nor repaired. The data indicate that the mutation results in a defect in repair of X-ray induced single-strand breaks as well as a defect in DNA replication. They provide evidence for the existence of a repair pathway for X-irradiated DNA similar to, but at least partially independent from, that postulated for the dark-repair of UV-irradiated DNA, viz., degradation at the site of the lesion, resynthesis of the degraded DNA complement and ligation of the DNA strand.

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The organization and repair of DNA in the mammalian chromosome. I. Calibration procedures and errors in the determination of the molecular weight of a native DNA

et al. 1977

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SynopsisThe semiautomated sucrose gradient system of Lange and Liberman (1974) (Anal. Biochem. 59,129-145) has been used to determine an accurate value of the exponent K of the Burgi and Hershey equation (1963) (Biophys. J. 3,309-321) under conditions of 1M salt. A complete analysis of the variance of k was done for data from both systems. The results lead to the conclusion that the value k = 0.401 (f0.012 for reproducibility; f0.019 for total error) obtained here is considerably more accurate than that of Burgi and Hershey (even when corrected for DNA concentration effects and the improved size estimates of T4 DNA size). The use of the Burgi and Hershey relationship and a T4 DNA metric to determine molecular weights of mammalian DNA requires the utmost precision in the exponent if useful estimates are to be obtained. This also has implications for double-strand breakage and repair estimates.

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Repair of X-ray damage to the DNA in Micrococcus radiodurans: the effect of 5-bromodeoxyuridine

Cited by 65 publications

References 12 publications

Oxidative Stress Resistance inDeinococcus radiodurans

Oxidative Stress Resistance inDeinococcus radiodurans

X-Irradiation sensitivity in Escherichia coli defective in DNA replication

The organization and repair of DNA in the mammalian chromosome. I. Calibration procedures and errors in the determination of the molecular weight of a native DNA

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