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Do bromine atoms incorporated into DNA obscure the photon-induced Auger effect on damage induction?
https://repo.qst.go.jp/records/76767
https://repo.qst.go.jp/records/76767aac35d10-484d-4fdb-a95e-0563696485f5
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2019-08-09 | |||||
| タイトル | ||||||
| タイトル | Do bromine atoms incorporated into DNA obscure the photon-induced Auger effect on damage induction? | |||||
| 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 |
Yokoya, Akinari
× Yokoya, Akinari× Yokoya, Akinari |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Despite the efforts by many groups, photon-induced Auger effects of halogenated DNA have not shown us a noticeable biological enhancement. Using monochromatized synchrotron X-rays above and below K-edges of bromine or iodine atom, the Auger enhancement ratios by these halogens have been revealed to be mostly less than 1.5, which were considerably lower than initially expected values [1]. On the other hand, conventional X-ray irradiation are well know to induce pronouced radiobiological rensitizations regardless of the halogenous Auger effect. The scarce Auger ehnancements could be interpreted as an obscuring effect of the strong halogeneous radiosensitization. Monte Calro simulation study suggested that an increase of DNA strand break yields due to Br/IdU incorporation could be explained by radical formation by interaction with hydrated electrons (eaq-) and direct energy deposition along radiation tracks, and also energy transfer in the DNA, resulting damage clustering [2]. To understand the radiosensitizaion mechanism of halogens, apart from their Ager effects, we studies electronic properties of BrU or BrdUMP using soft X-ray absorption or photoelectron spectroscopy, and specific heat measurement for estimating the microscopic state number. Evidences accumulated are as follows. 1)The core (1s) levels of the molecules are not affected by exsistence of the bromine atom. 2)Resonance from the core to LUMO states are also not affected by exsistence of the bromine atom. 3)Bromine atom may not significantly contribute to the electronic states, but the state related to the excitation of lattice vibration (oscillation and rotation in the molecule). It could be shown that valence electrons or much lower energy phonon excitation might play an important role for DNA damage enhancement rather than core level electronic states. [1] Yokoya, A. and Ito, T., Int. J. Radiat. Biol. 93, 743-756 (2017). [2] Watanabe, R. and Nikjoo, H., Int. J. Radiat. Biol. 78, 953-966 (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 9th International Symposium on Physical, Molecular, Cellular, and Medical Aspects of Auger Processes | |||||
| 発表年月日 | ||||||
| 日付 | 2019-08-23 | |||||
| 日付タイプ | Issued | |||||
