1986 Fiscal Year Final Research Report Summary
Roles of active oxyradicals in radiation biology-- basic aspects
| Project/Area Number |
60580164
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
放射線5生物学
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| Research Institution | University of Tokyo |
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Principal Investigator |
ITO Takashi University of Tokyo, College of Arts and Sciences, 教養部, 教授 (00012245)
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| Project Period (FY) |
1985 – 1986
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| Keywords | OH radical / Photolysis of water / Degradation of Oligonucleotide / Inactivation of yeast / 糖の分解 |
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| Research Abstract |
The purpose of this project is to collect information on the basic aspects of radiation action on the DNA, related compounds and living cells (yeast) with special emphasis on the role of OH radicals and other agents supposed to cause a similar intermediary state. For a clean source of OH radicals the photolysis of water by vacuum-UV radiation was used. For a direct means of presumed radical production, vacuum-UV irradiation in solid was employed. Treatment with <H_2O_2> was also examined in view of the OH radical production through the Fenton-type reaction. The plan for <O_2^-> effect was not able to carry out.
The notable results are as follows:
1. Nucleotide and nucleoside release base residue upon direct photon absorption. 2. Upon direct irradiation pBR322 DNA stimulates poly(ADP-ribose) synthetase with very high efficiency in in vitro system. 3. Spin-trap experiments show the production of OH adducts both for base and sugar in nucleoside. 4. Oligonucleotide, dApdA, releases adenine and 5'-dAMP at the same rate by direct photon absorption but in the indirect action mode (OH radical) the base moiety also decomposes in the presence of <O_2> . 5. <H_2O_2> treatment causes the production of thymine glycol in the cellular DNA of yeast. It seems that OH radicals react with DNA and related compounds by H abstraction and formation of adducts and that sugar moiety may be the most vulnerable target regardless of direct or indirect action modes.
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