Ultraviolet Difference Spectral Studies in the Gamma Radiolysis of DNA and Model Compounds. I. Aqueous Solutions of DNA Bases

Trumbore, Conrad N.; Hyde, C.T.; Hudson, R. D.; Jurman, L.A.; Gehring, A.G.; Masselink, J K

doi:10.1080/09553008914552391

Cited by 7 publications

(2 citation statements)

References 30 publications

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“…Individual fractions containing each pure product were dried under vacuum and stored at −80 °C for the future use. The products were characterized by UV spectroscopy, mass spectral analysis (see Figure S1 in Supplementary Information) and HPLC retention relative to defined standards (14,(33)(34)(35).…”

Section: Preparation Of Uniformly 13 C 15 N-labeled Da Dg and Dcmentioning

confidence: 99%

Relatively Small Increases in the Steady-State Levels of Nucleobase Deamination Products in DNA from Human TK6 Cells Exposed to Toxic Levels of Nitric Oxide

Dong

Dedon

2005

Chem. Res. Toxicol.

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Nitric oxide (NO) is a physiologically important molecule that has been implicated in the pathophysiology of diseases associated with chronic inflammation, such as cancer. While the complicated chemistry of NO-mediated genotoxicity has been extensively study in vitro, neither the spectrum of DNA lesions nor their consequences in vivo have been rigorously defined. We have approached this problem by exposing human TK6 lymphoblastoid cells to controlled steady-state concentrations of 1.75 or 0.65 μM NO along with 186 μM O 2 in a recently developed reactor that avoids the anomalous gas-phase chemistry of NO and approximates the conditions at sites of inflammation in tissues. The resulting spectrum of nucleobase deamination products was defined using a recently developed liquid chromatography/mass spectrometry (LC/MS) method and the results were correlated with cytotoxicity and apoptosis. A series of control experiments revealed the necessity of using dC and dA deaminase inhibitors to avoid adventitious formation of 2′-deoxyuridine (dU) and 2′-deoxyinosine (dI), respectively, during DNA isolation and processing. Exposure of TK6 cells to 1.75 μM NO and 186 μM O 2 for 12 hr (1260 μM•min dose) resulted in 32% loss of cell viability measured immediately after exposure and 87% cytotoxicity after a 24 hr recovery period. The same exposure resulted in 3.5-, 3.8-, and 4.1-fold increases in dX, dI and dU, respectively, to reach the following levels: dX, 7 (±1) per 10 6 nt; dI, 25 (±2.1) per 10 6 nt; and dU, 40 (±3.8) per 10 6 per nt. dO was not detected above the limit of detection of 6 lesions per 10 7 nt in 50 μg of DNA. A 12 hr exposure to 0.65 μM NO and 190 μM O 2 (468 μM•min dose) caused 1.7-, 1.8-, and 2.0-fold increases in dX, dI, and dU, respectively, accompanied by a ∼15 (±3.6) % reduction in cell viability immediately after exposure. Again, dO was not detected. These results reveal modest increases in the steady-state levels of DNA deamination products in cells exposed to relatively cytotoxic levels of NO. This could result from limited nitrosative chemistry in nuclear DNA in cells exposed to NO or high levels of formation balanced by rapid repair of nucleobase deamination lesions in DNA.

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Section: Preparation Of Uniformly 13 C 15 N-labeled Da Dg and Dcmentioning

confidence: 99%

Relatively Small Increases in the Steady-State Levels of Nucleobase Deamination Products in DNA from Human TK6 Cells Exposed to Toxic Levels of Nitric Oxide

Dong

Dedon

2005

Chem. Res. Toxicol.

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“…Absorption spectra were recorded using a Varian Cary‐50 with a scan rate of 600 nm min −1 . Each difference spectrum is the absolute difference of the UVC‐irradiated DNA spectrum minus the nonirradiated control DNA spectrum, a procedure utilized in the literature (14).…”

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Effect of UVC-Induced Damage to DNA on the Intercalation of Thiazole Orange: A Convenient Reporter for DNA Damage†

Trevithick-Sutton

Mikelsons

Filippenko

et al. 2007

Photochemistry and Photobiology

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We report a novel method of identifying damage to DNA leading to the loss of intercalation sites. Thiazole orange (TO), an intercalating cyanine dye, fluoresces strongly when intercalated in DNA, but not free in solution. Upon UVC-induced damage to DNA, the change in TO fluorescence is greater than the change in any of the other spectral or biochemical indicators (absorbance, circular dichroism and agarose gel electrophoresis), thus providing a fast screening method to identify damage to DNA. The method is geared toward high levels of damage, such as those that may result during radiation treatment of food products.

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Absorption and fluorescence behavior of cytosine irradiated at different pH and in the presence of Cu(II) ions at neutral pH

Chabita

Mandal

Bhattacharyya

1994

Journal of Radioanalytical and Nuclear Chemistry Letters

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Ultraviolet Difference Spectral Studies in the Gamma Radiolysis of DNA and Model Compounds. I. Aqueous Solutions of DNA Bases

Cited by 7 publications

References 30 publications

Relatively Small Increases in the Steady-State Levels of Nucleobase Deamination Products in DNA from Human TK6 Cells Exposed to Toxic Levels of Nitric Oxide

Relatively Small Increases in the Steady-State Levels of Nucleobase Deamination Products in DNA from Human TK6 Cells Exposed to Toxic Levels of Nitric Oxide

Effect of UVC-Induced Damage to DNA on the Intercalation of Thiazole Orange: A Convenient Reporter for DNA Damage†

Absorption and fluorescence behavior of cytosine irradiated at different pH and in the presence of Cu(II) ions at neutral pH

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