Comparison of the effects of high-power U.V.-laser pulses and ionizing radiation on nucleic acids and related compounds

Angelov, Dimitar; Berger, M.; Cadet, Jean; Getoff, N.; Keskinova, E.; Solar, Sonja

doi:10.1016/1359-0197(91)90171-w

Cited by 12 publications

(15 citation statements)

References 72 publications

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“…Kadical cations can also be produced photolytically by the action of vacuum-UV, e.g. with monochromatic synchrotron radiation (40)(41)(42)(43) or by a two-quanta-induced method with high-intensity far-UV irradiation, the wavelength is typically 248 or 266 nm (52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64)(65). The energy of the photons with hi,, = 193 nm (6.4 eV) corresponds to the transition to the second excited singlet state, So + S,, which is above the ionization limit.…”

Section: Introductionmentioning

confidence: 99%

Depopulation of Highly Excited Singlet States of DNA Model Compounds: Quantum Yields of 193 and 245 nm Photoproducts of Pyrimidine Monomers and Dinucleoside Monophosphates

Gurzadyan¹,

Görner²

1996

Photochem & Photobiology

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Formation of uracil and orotic acid photodimers, uridine and 5'-UMP photohydrates, TpT photodimers and (6-4)photoproducts, dCpT photohydrates and (6-4)photoproducts and UpU, CpC and CpU photohydrates were studied in neutral deoxygenated aqueous solution at room temperature upon irradiation at either 193 or 254 nm. The photoproducts were identified and quantified and the contribution from photoionization to substrate decomposition, using lambda irr = 193 nm, was separated. The ratio of the quantum yields of respective stable products, eta = phi 193/phi 254, is indicative of the yield of internal conversion from the second to the first excited singlet state, S2-->S1. For the observed photodimers eta decreases from 0.94 for uracil to 0.7 for TpT and further to 0.55 for orotic acid. For the (6-4)photoproducts of TpT and dCpT eta = 0.5-0.8 and for the photohydrates in the cases of UpU, CpC, CpU and dCpT eta ranges from 0.55 to 1.

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Section: Introductionmentioning

confidence: 99%

Depopulation of Highly Excited Singlet States of DNA Model Compounds: Quantum Yields of 193 and 245 nm Photoproducts of Pyrimidine Monomers and Dinucleoside Monophosphates

Gurzadyan¹,

Görner²

1996

Photochem & Photobiology

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“…The track model of energy deposition of ionizing radiation in an aqueous medium provides the concept of free radical formation in track entities such as spurs and blobs, which may be formed in the vicinity of DNA bases (reviewed in Chatterjee 1987). The direct effect of radiation on DNA may also account in part for the formation of modified bases through ionization of DNA bases (reviewed in Steenken 1989 andAngelov et al 1991). Of the modified bases measured in chromatin of irradiated cells, the yields of guanine-derived bases were the highest (e.g., = 45 % of the net total yield of modified bases, when calculated from the yields at 116 Gy after subtraction of background values).…”

Section: Basementioning

confidence: 99%

Ionizing Radiation-Induced DNA Damage and Its Repair in Human Cells

Dizdaroğlu¹

1999

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“…Concerning mechanistic aspects, it seems to us that the far-UV photochemistry of DNA (cf. Gurzadyan et al, 1982;Rahn and Patrick, 1976;H6l&ne, 1987;Cadet and Vigny, 1990;Angelov et al, 1991) is not as advanced as the radiation chemistry (cf. von Sonntag, 1987).…”

Section: (-H+)mentioning

confidence: 99%

STRAND BREAKAGE IN POLY(C), POLY(A), SINGLE‐AND DOUBLE‐STRANDED DNA INDUCED BY NANOSECOND LASER EXCITATION AT 193 nm*

Görner

Wala

Schulte‐Frohlinde

1992

Photochem & Photobiology

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Single- and double-stranded calf thymus DNA and two polynucleotides (0.4 mM) were studied in aqueous solution at pH approximately 7 using pulsed, 20 ns laser excitation at 193 nm. Monophotonic ionization of the nucleic acids is suggested from the linear dependences of the concentration of ejected electrons and the number of single- and double-strand breaks (ssb, dsb, respectively) on laser intensity (IL) in the range (0.2-3) x 10(6) W cm-2. The quantum yields of formation of hydrated electrons (phi e-) and ssb and dsb (phi ssb and phi dsb) are therefore independent of IL. In contrast, under 248 nm excitation these quantum yields increase linearly with IL under otherwise comparable conditions. Nevertheless, several effects and mechanistic implications are analogous using lambda exc = 193 and 248 nm. For polycytidylic acid, poly(C), in Ar-saturated solution for example, the efficiency of ssb per radical cation (eta RC = phi ssb/phi e-) is similar to the efficiency of ssb per OH radical (eta OH). For polyadenylic acid, poly(A), and single- and double-stranded DNA eta RC (lambda exc = 193 nm) is significantly smaller than eta OH. The ratio phi ssb (N2O)/phi ssb (Ar) is approximately 2 for poly(C), approximately 4 for poly(A) approximately 10 for DNA; the conversion of hydrated electrons into OH radicals in N2O-saturated solution and smaller eta RC than eta OH values in the case of DNA account for these results. For double-stranded DNA phi dsb does not depend on IL but increases linearly with the dose, indicating an accumulative effect of two ssb to generate one dsb. The critical distance for this event is 60-85 phosphoric acid diester bonds.

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Comparison of the effects of high-power U.V.-laser pulses and ionizing radiation on nucleic acids and related compounds

Cited by 12 publications

References 72 publications

Depopulation of Highly Excited Singlet States of DNA Model Compounds: Quantum Yields of 193 and 245 nm Photoproducts of Pyrimidine Monomers and Dinucleoside Monophosphates

Depopulation of Highly Excited Singlet States of DNA Model Compounds: Quantum Yields of 193 and 245 nm Photoproducts of Pyrimidine Monomers and Dinucleoside Monophosphates

Ionizing Radiation-Induced DNA Damage and Its Repair in Human Cells

STRAND BREAKAGE IN POLY(C), POLY(A), SINGLE‐AND DOUBLE‐STRANDED DNA INDUCED BY NANOSECOND LASER EXCITATION AT 193 nm*

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