Download or read book Study of the Effects of Radiation of Nucleic Acids and Related Compounds Progress Report August 15 1975 August 14 1976 written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Ionizing radiation produces genetic effects in biological systems. Since genetic effects are usually the result of modifications of DNA or sometimes of RNA, interest is being centered on the chemical and physical nature of radiation-induced lesions to nucleic acids and their components. These investigations have revealed the enormous complexity of chemical events and the possible degradation of nucleic acids by strand breakage. Therefore, work in the ionization radiation of nucleic acids has proceeded along a dual course. On the one hand, molecular changes have been characterized for a number of primary radiation products. On the other hand, strand breakage has been investigated intensively as a direct primary event. Both of these aspects were emphasized in our research last year. We succeeded in improving the synthesis of 5-hydroxy-methyl thymine (.cap alpha.-TOOH). .cap alpha.-TOOH was found to be much more effective than cis-5,6-dihydro-6-hydroperoxy-5-hydroxy thymine (6-TOOH) in the inactivation of transforming DNA of H. influenzae cells although .cap alpha.-TOOH is much less reactive chemically than 6-TOOH. 6-TOOH causes inactivation and acts as an inhibitor of DNA synthesis in mammalian cells. In addition, evidence may indicate that 6-TOOH does not induce strand breaks directly in DNA although we showed that 6-TOOH is a clastogenic compound. (auth).
Download or read book Study of the Radiation Effects on Nucleic Acids and Related Compounds Progress Report August 15 1976 November 14 1977 written by and published by . This book was released on 1977 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The effects of ionizing radiation on nucleic acids and components were studied in vitro. Our approach involves four levels of operation and progress is being made at each stage. First, procedures were established to separate and purify three reactive radiation products from thymidine. Second, improved methods of synthesizing trans-glycols of pyrimidines were developed, and a new method for the stereospecific synthesis of cis-glycol of pyrimidines was realized. Thirdly, the Ames Salmonella test was used to determine the mutagenicity of the radiation products and the reactive ones from thymine and thymidine were found to be highly mutagenic. Therefore, all radiation products should be considered potential human health hazards and should be screened when they can be purified and synthesized. In the fourth stage, the reaction of each nucleic-acid base with Cu/sup + +/ and cis-5,6-dihydro-6-hydroperoxy-5-hydroxythymine (6-TOOH) was studied in order to further our understanding of the molecular mechanisms of radiation mutagenesis. The presence of Cu/sup + +/ was shown to be necessary for the effective mutagenic activity of 6-TOOH in the H. influenzae transformation assay. These findings provide fundamental information about the possible health hazards of ionizing radiation and will be useful in designing methods to protect against and repair radiation damage, which may be mutagenic and carcinogenic.
Download or read book Study of the Radiation Effects on Nucleic Acids and Related Compounds Annual Progress Report August 15 1974 August 14 1975 X Radiation Hamster Cells Haemophilus Influenzae written by and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest is being centered on the chemical and physical nature of radiation-induced lesions to nucleic acids and their components. These investigations have revealed the enormous complexity of chemical events in these systems and the possible degradation of nucleic acids by strand breakage. Therefore, work in the ionizing radiation of DNA and its components has proceeded along a dual course. For chemical studies, our prime concern is the stepwise isolation and identification of the radiation products of derivatives of pyrimidines and the study of the actual mechanisms of their formation. For biological studies, H. influenzae cells, the Chinese hamster V79B-1 cell line, and the Dunn osteosarcoma lung colony system were used. During the last year, the method of synthesis of 5-hydroperoxymethyluracil (T/sub .cap alpha./OOH) was greatly improved. Large-scale preparation of 5-hydroxy-6-hydroperoxy-5,6-dihydrothymine (T6OOH) were carried out in order to study the action of T6OOH on neighboring bases, glycosidic bond-breakage, cell mutagenesis, chromosomal aberrations, and possible synergistic effects on x radiation. These results allow one to relate radiobiological effects with radiation chemical changes in DNA.
Download or read book Study of the Effects of Radiation on Nucleic Acids and Related Compounds Progress Report August 15 1973 August 14 1974 written by and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Study of the Effects of Radiation on Nucleic Acids and Related Compounds Annual Progress Report August 1972 July 1973 written by and published by . This book was released on 1973 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Chemical Study of the Effects of Radiation on Nucleic Acids and Related Compounds Three Year Progress Report June 1969 May 1972 written by and published by . This book was released on 1972 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1976 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration and published by . This book was released on 1977 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ERDA Energy Research Abstracts written by United States. Energy Research and Development Administration. Technical Information Center and published by . This book was released on 1976 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low level Radiation written by United States. Department of Energy. Technical Information Center and published by . This book was released on 1978 with total page 740 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Annual Index written by and published by . This book was released on 1977 with total page 874 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book Government Reports Announcements Index written by and published by . This book was released on with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Accessions of Unlimited Distribution Reports written by and published by . This book was released on 1976-07-02 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1978 with total page 1190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book INIS Atomindex written by and published by . This book was released on 1977 with total page 868 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1975 with total page 764 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1978 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt: Semiannual, with semiannual and annual indexes. References to all scientific and technical literature coming from DOE, its laboratories, energy centers, and contractors. Includes all works deriving from DOE, other related government-sponsored information, and foreign nonnuclear information. Arranged under 39 categories, e.g., Biomedical sciences, basic studies; Biomedical sciences, applied studies; Health and safety; and Fusion energy. Entry gives bibliographical information and abstract. Corporate, author, subject, report number indexes.
