Download or read book The Use of UV Resonance Raman Spectroscopy in the Analysis of Ionizing Radiation induced Damage in DNA written by and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Raman spectroscopy is a form of vibrational spectroscopy that is capable of probing biological samples at a molecular level. In this work it was used in the analysis of ionizing radiation-induced damage in DNA. Spectra of both simple, short-stranded DNA oligomers (SS-DNA) and the more complicated calf-thymus DNA (CT-DNA) were acquired before and after irradiation to a variety of doses from 0 to ~2000 Gy. In a technique known as ultraviolet resonance Raman spectroscopy (UVRRS), three UV wavelengths of 248, 257 and 264 nm were utilized in order to selectively enhance contributions from different molecular groups within the samples. Assignment of the spectral peaks was aided by the literature, as well as through analysis of UVRR spectra of short strands of the individual DNA bases obtained at each of the three incident UV wavelengths. Difference spectra between the irradiated and unirradiated samples were calculated and the samples exposed to ~2000 Gy showed significant radiation-induced features. Intensity increases of spectral peaks, observed primarily in the CT-DNA, indicated unstacking of the DNA bases and disruption of Watson-Crick hydrogen bonds, while intensity decreases of spectral peaks, observed only in the SS-DNA, indicated both base damage and the loss of structural integrity of the DNA molecule. The high molecular specificity of UVRRS allowed for precise identification of the specific bonds affected by the radiation, and the use of the varying incident wavelengths allowed for the observation of damage to moieties that would otherwise have been excluded. The use of UVRRS shows promise in the study of radiation-induced damage to DNA and would be well suited for extension to the study of more complicated biological systems.

Download or read book Applied Spectroscopy written by and published by . This book was released on 2009 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ionizing Radiation Damage to DNA written by Radiation Research Society (U.S.) and published by . This book was released on 1990-09-13 with total page 358 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprised of a series of short papers, dedicated exclusively to the molecular aspects of ionizing radiation-induced damage and its subsequent biological processing. Representing a scientific cross-section, with contributions by major researchers in the field, it examines new and innovative methodologies for detecting and quantifying the broad spectrum of DNA damage, spotlights the use of recombinant DNA technologies for introducing unique model lesions into DNA, and assesses their mutagenic potential.

Download or read book Effects of Ionizing Radiation on DNA written by G. Ahnström and published by Springer. This book was released on 1978 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book DNA and Chromatin Damage Caused by Radiation written by John T. Lett and published by Academic Press. This book was released on 2013-10-22 with total page 520 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Radiation Biology, Volume 17: DNA and Chromatin Damage Caused by Radiation outlines the different biological reactions to radiation. This book discusses the linear energy transfer and energy loss; DNA breaks and track structure; DNA radicals from water radicals; and radiation-induced strand breaks in isolated DNA. The radiation damage to DNA and its nearby environment; thiol radioprotectors and mechanism of action; radiolysis of water and track reactions; and computer simulation of higher order structure of DNA are also elaborated. This publication likewise covers the concept of chromatin structure; DNA supercoiling studied by sedimentation; measurement of radiation-induced DNA breakage; and analysis of damage in interphase cells. This volume is a useful reference to biologists and students concerned with DNA and chromatin damage caused by radiation.

Download or read book Free Radical Induced DNA Damage and Its Repair written by Clemens Sonntag and published by Springer Science & Business Media. This book was released on 2006-03-20 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: The free-radical chemistry of DNA had been discussed in some detail in 1987 in my book The Chemical Basis of Radiation Biology. Obviously, the more recent developments and the concomitant higher level of understanding of mechanistic details are missing. Moreover, in the living cell, free-radical DNA damage is not only induced by ionizing radiation, but free-radical-induced DNA damage is a much more general phenomenon. It was, therefore, felt that it is now timely to review our present knowledge of free-radical-induced DNA damage induced by all conceivable free-radical-generating sources. Originally, it had been thought to include also a very important aspect, the repair of DNA damage by the cell’s various repair enzymes. Kevin Prise (Cancer Campaign, Gray Laboratory, L- don) was so kind to agree to write this part. However, an adequate description of this strongly expanding area would have exceeded the allocated space by much, and this section had to be omitted. The directors of the Max-Planck-Institut für Strahlenchemie (now MPI für Bioanorganische Chemie), Karl Wieghardt and Wolfgang Lubitz, kindly allowed me to continue to use its facilities after my retirement in 2001. Notably, our - brarian, Mrs. Jutta Theurich, and her right-hand help, Mrs. Rosemarie Schr- er, were most helpful in getting hold of the literature. I thank them very much. Without their constant help, this would have been very difficult indeed.

Download or read book Mechanisms of DNA Damage and Repair written by Michael G. Simic and published by Springer Science & Business Media. This book was released on 2013-11-21 with total page 567 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on the papers presented at the conference on "Mecha nisms of DNA Damage and Repair: Implications for Carcinogenesis and Risk Assessment," held at the National Bureau of Standards on June 2-7, 1985, This volume deals with mechanisms of DNA damage and repair at the molecular level; consequences of unrepaired or misrepaired damage, with major emphasis on carcinogenesis; drugs which bind selectively to altered and potentially damaging DNA sequences; and potential utilization of DNA damage as an endpoint for assessing risks of UV light, ionizing radiations, chemicals, drugs, and hazardous agents in foods. Because the induction of mutations by radiation and genotoxic chemicals has been observed to follow one-hit kinetics in some instances, it is generally assumed that any level of exposure to a DNA-damaging agent may increase the risk of genetic disease or cancer in an exposed population. At the same time, however, there is evidence that although the DNA of living cells is continually damaged by natural background radiation, free radicals, and other naturally occurring processes, most of the damage is normally repaired.

Download or read book Ionizing Radiation Induced DNA Damage and Its Repair in Human Cells written by and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: DNA damage in mammalian chromatin in vitro and in cultured mammalian cells including human cells was studied. In the first phase of these studies, a cell culture laboratory was established. Necessary equipment including an incubator, a sterile laminar flow hood and several centrifuges was purchased. We have successfully grown several cell lines such as murine hybridoma cells, V79 cells and human K562 leukemia cells. This was followed by the establishment of a methodology for the isolation of chromatin from cells. This was a very important step, because a routine and successful isolation of chromatin was a prerequisite for the success of the further studies in this project, the aim of which was the measurement of DNA darnage in mammalian chromatin in vitro and in cultured cells. Chromatin isolation was accomplished using a slightly modified procedure of the one described by Mee & Adelstein (1981). For identification and quantitation of DNA damage in cells, analysis of chromatin was preferred over the analysis of"naked DNA" for the following reasons: i. DNA may not be extracted efficiently from nucleoprotein in exposed cells, due to formation of DNA-protein cross-links, ii. the extractability of DNA is well known to decrease with increasing doses of radiation, iii. portions of DNA may not be extracted due to fragmentation, iv. unextracted DNA may contain a significant portion of damaged DNA bases and DNA-protein cross-links. The technique of gas chromatography/mass spectrometry (GC/MS), which was used in the present project, permits the identification and quantitation of modified DNA bases in chromatin in the presence of proteins without the necessity of first isolating DNA from chromatin. This has been demonstrated previously by the results from our laboratory and by the results obtained during the course of the present project. The quality of isolated chromatin was tested by measurement of its content of DNA, proteins, and RNA, by analysis of its protein components using gel electrophoresis, and by absorption spectral analysis. GeneraUy, the RNA content was

Download or read book Ionizing Radiation induced DNA Damage and Repair in Relation to Biological Function written by Boris Kysela and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Radiation induced and oxidative DNA damages written by Antonio Monari and published by Frontiers Media SA. This book was released on 2015-10-02 with total page 95 pages. Available in PDF, EPUB and Kindle. Book excerpt: DNA stores and passes the genetic information of almost all living organisms. Its molecular structure and their intramolecular interactions are particularly suitable to maximize stability against oxidative stress and UV-light absorption. Yet the protection and repair strategies are still error-prone: DNA lesions are produced, including the most complex and highly mutagenic ones. An important threat to DNA stability comes from photosensitization, i.e. from the dramatic multiplication of radiation-induced defects mediated by the presence of organic or organometallic dyes compared to the direct exposure to UVA radiation. Moreover, the photo-induced production of singlet oxygen generates an extremely high oxidative stress on DNA that, in vivo, normally results in extended cellular apoptosis. Elucidating the processes leading to DNA damages, from the production of a simple radical entity to deleterious lesions, as well as the opportunities of repair by devoted enzymes, is a cornerstone towards the development of more efficient protection strategies. Sensitization and selective production of DNA lesions can also be exploited to induce the selective apoptosis of cancer cells upon exposition to radiation or to oxidative stress, for instance in the field of photodynamic therapy. The importance and relevance of the field is witnessed by the impressive amount of high-level papers dealing with this complex subject, and notably tackling the structural elucidation of DNA and DNA-drug adducts, the mechanisms of formation of DNA lesions (including the precise detection of the final lesion products), as well as the influence of the lesions on the DNA stability and dynamics and the consequences on the ease of repair. Due to the complexity of the field lying at the frontiers between chemistry, physics and biology, multidisciplinary strategies allying modeling and experience are needed. This topic aims at giving an extended overview of the current research in the domain, with fundamental contribution from the leading groups in the field of DNA reactivity, structural characterization, photo-chemistry and photo-physics, as well as repair mechanism. It will therefore be a fundamental guide for scientists wanting to address the field of DNA lesion and repair, but also more generally for researchers working in rational drug design or in the development of biomarkers and medical imaging techniques

Download or read book The Early Effects of Radiation on DNA written by E.M. Fielden and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 437 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in the biological effects of ionising radiation closely followed the identification of such radiation. The realisation that DNA is the site of genetic infonnation in cells subsequently focussed attention on DNA as an important target in the lethal and mutagenic effects of ionising radiation. Thus radiation effects upon DNA became an important area for fundamental scientific studies by radiation biologists, chemists and physicists. To a first approximation, the concerns of the three disciplines can be divided by time scales: the physical process of energy deposition from photon or charged 16 12 particle and subsequent relaxation (-10- to 10- secs), followed by chemical 12 2 reactions (- 10- to 10 secs), and fmally, the expression of biological effect (minutes to years). Thus, the concept of 'early processes' conveys different ideas to different scientists, although they are all interrelated. To attempt to describe in any detail all these processes is a mammoth task which is not made easier by the different conventions and experimental approaches of the three disciplines. However, the recent advances in all these scientific areas seemed, to the organisers at least, to offer the opportunity to stimulate more active interaction between physicists, chemists and biologists. With this in mind, a multi-disciplinary workshop was organised, which brought together some fifty scientists to present their own specialist interests and, through extensive discussion, explore which problems are of high priority and require input from the different disciplines to resolve them.

Download or read book Cumulated Index Medicus written by and published by . This book was released on 1981 with total page 976 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Radiation Damage in DNA written by Alfred F. Fuciarelli and published by . This book was released on 1995 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Free Radical and Radiation Induced Damage to DNA written by D. Schulte-Frohlinde and published by CRC Press. This book was released on 1989 with total page 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatiotemporal Characterization of Ionizing Radiation Induced DNA Damage Foci and Their Relation to Chromatin Organization written by and published by . This book was released on 2009 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: DNA damage sensing proteins have been shown to localize to the sites of DSB within seconds to minutes following ionizing radiation (IR) exposure, resulting in the formation of microscopically visible nuclear domains referred to as radiation-induced foci (RIF). This review characterizes the spatio-temporal properties of RIF at physiological doses, minutes to hours following exposure to ionizing radiation, and it proposes a model describing RIF formation and resolution as a function of radiation quality and nuclear densities. Discussion is limited to RIF formed by three interrelated proteins ATM (Ataxia telangiectasia mutated), 53BP1 (p53 binding protein 1) and?H2AX (phosphorylated variant histone H2AX). Early post-IR, we propose that RIF mark chromatin reorganization, leading to a local nuclear scaffold rigid enough to keep broken DNA from diffusing away, but open enough to allow the repair machinery. We review data indicating clear kinetic and physical differences between RIF emerging from dense and uncondensed regions of the nucleus. At later time post-IR, we propose that persistent RIF observed days following exposure to ionizing radiation are nuclear?scars? marking permanent disruption of the chromatin architecture. When DNA damage is resolved, such chromatin modifications should not necessarily lead to growth arrest and it has been shown that persistent RIF can replicate during mitosis. Thus, heritable persistent RIF spanning over tens of Mbp may affect the transcriptome of a large progeny of cells. This opens the door for a non DNA mutation-based mechanism of radiation-induced phenotypes.

Download or read book Characterization of Ionizing Radiation Damage in DNA Progress Report May 1 1975 April 30 1976 written by and published by . This book was released on 1976 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research is the characterization and quantitative assay of ionizing radiation-induced damage in DNA and nucleoprotein. Two lines of investigation have been pursued. The first is aimed at detection and assay of DNA to protein covalent cross linkage in coliphage T7. Protein and DNA are labeled with $sup 14$C and $sup 32$P, respectively. Cross linkage is assessed from the amount of labeled protein distributing like DNA and labeled DNA distributing like protein on a phenol-water countercurrent distribution system. It has been found that damage involving cross linkage occurs by two modes of radiation action in phage irradiated with $sup 60$Co $gamma$ rays in .001M histidine medium. Indirect effects play a large role in one mode and direct effects play a large role in the other. In the second line of investigation, the hydrodynamic and viscoelastic properties of DNA from irradiated phage and cells will be examined to determine the extent to which DNA to DNA cross linkage and points of altered flexibility are introduced by radiation. An instrument for viscoelastic measurements has been constructed in preparation for these studies. (auth).

Download or read book Analysis of X ray Induced DNA Double strand Breaks Using Pulsed Field Gel Electrophoresis written by Björn Cedervall and published by . This book was released on 1995 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: