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Effects of additives on radiation-induced DNA damage: from the viewpoints of free radical scavenging and chemical repair
https://repo.qst.go.jp/records/77099
https://repo.qst.go.jp/records/770995bda8b1c-33d9-4731-bc8e-6d410eae998e
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2019-10-07 | |||||
| タイトル | ||||||
| タイトル | Effects of additives on radiation-induced DNA damage: from the viewpoints of free radical scavenging and chemical repair | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
YU, Hao
× YU, Hao× Fujii, Kentaro× Yokoya, Akinari× Shinichi, Yamashita(The University of Tokyo)× YU, Hao× Kentaro, Fujii× Akinari, Yokoya |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | 1. INTRODUCTION Radiation-induced DNA damage can be reduced by small amount of additives like antioxidants. Such additives can repair unstable oxidative damage intermediately produced in DNA by reductive reaction (chemical repair) as well as remove oxidizing radicals such as •OH produced as a result of water radiolysis (radical scavenging). Low concentration of additives cannot remove all of the oxidizing radicals, therefore, the chemical repair process must be more important. We investigated the effect of additives against radiation damage to DNA. For this purpose, pulse radiolysis experiments were conducted to observe the additive’s reactions not only with radicals produced by water radiolysis but also with a tentatively oxidized DNA model compound. In this study, dGMP (deoxyguanosine monophosphate, purchased from Thermo Fisher Scientific) was used as model compound of DNA moiety. In addition, a gel electrophoresis was conducted to evaluate the yield of stable DNA damage. 2. EXPERIMENT Pulse radiolysis was conducted at the LINAC facility of the University of Tokyo. Details of the apparatus are described in elsewhere[1]. Plasmid DNA, pUC18, was extracted from cultured Escherichia coli (JM109) and purified by dialysis to remove organic impurities. Dilute aqueous solutions and films of the plasmid DNA were irradiated with X-rays and stable DNA damage were detected and quantified by an agarose gel electrophoresis method[2]. As additives, we used Tris-EDTA (TE), which are the solutes of pH buffer often used for DNA storage, and typical antioxidants such as ascorbic acid (purchased from Fujifilm Wako) and flavonoid rutin (received from Toyo Sugar or purchased from Fujifilm Wako). 3. RESULTS & DISCUSSION Transient absorption spectra of the scavenging reaction of rutin toward •OH had at least three peaks, which were attributed to the products of OH adduct, hydrogen atom subtraction, and electron subtraction. The ratio of the peak intensities was not constant, indicating an intramolecular transformaton following the scavenging reaction. On the other hand, the reacion of rutin toward tentatively oxidized dGMP radical showed a clear peak in the spectra, which was the same as the peak corresponding to hydrogen abstraction observed for the scavenging reaction as described above. Purification by dialysis resulted in higher yields of stable DNA damage induction, indicating that non-negligible impurities could protect the DNA from radiation damage. The damage yields in dilute aqueous solutions were much higher than those in hydrated plasmid DNA films. This suggests that additional damage is produced due to the indireact actions of radicals produced by watar radiolysis. References [1] K. Hata, et al., J. Radiat. Res., 52, 15 (2011). [2] A. Yokoya et. Al., J. Am. Chem. Soc. 124, 8859 (2002). |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | The 31st Miller Conference on Radiation Chemistry | |||||
| 発表年月日 | ||||||
| 日付 | 2019-09-09 | |||||
| 日付タイプ | Issued | |||||
