Damage Avoidance and Repair Mechanisms of Extreme Halophiles to Ionizing Radiation

2013 ◽  
Author(s):  
Jocelyne DiRuggiero
Keyword(s):  
Ionizing Radiation ◽  
Extreme Halophiles ◽  
Repair Mechanisms ◽  
Damage Avoidance

scholarly journals Roles of the Major, Small, Acid-Soluble Spore Proteins and Spore-Specific and Universal DNA Repair Mechanisms in Resistance of Bacillus subtilis Spores to Ionizing Radiation from X Rays and High-Energy Charged-Particle Bombardment

2007 ◽  
Vol 190 (3) ◽  
pp. 1134-1140 ◽  
Author(s):  
Ralf Moeller ◽  
Peter Setlow ◽  
Gerda Horneck ◽  
Thomas Berger ◽  
Günther Reitz ◽  
...  
Keyword(s):  
Dna Repair ◽  
Bacillus Subtilis ◽  
Ionizing Radiation ◽  
Particle Bombardment ◽  
Strand Break ◽  
High Energy ◽  
X Rays ◽  
Repair Mechanisms ◽  
Spore Proteins ◽  
Genome Protection

ABSTRACT The role of DNA repair by nonhomologous end joining (NHEJ), homologous recombination, spore photoproduct lyase, and DNA polymerase I and genome protection via α/β-type small, acid-soluble spore proteins (SASP) in Bacillus subtilis spore resistance to accelerated heavy ions (high-energy charged [HZE] particles) and X rays has been studied. Spores deficient in NHEJ and α/β-type SASP were significantly more sensitive to HZE particle bombardment and X-ray irradiation than were the recA, polA, and splB mutant and wild-type spores, indicating that NHEJ provides an efficient DNA double-strand break repair pathway during spore germination and that the loss of the α/β-type SASP leads to a significant radiosensitivity to ionizing radiation, suggesting the essential function of these spore proteins as protectants of spore DNA against ionizing radiation.

scholarly journals GENETIC CONTROL OF RADIATION SENSITIVITY IN SCHIZOSACCHAROMYCES POMBE

Genetics ◽  
1975 ◽  
Vol 79 (4) ◽  
pp. 573-582
Author(s):  
A Nasim ◽  
B P Smith
Keyword(s):  
Ionizing Radiation ◽  
Genetic Analysis ◽  
Schizosaccharomyces Pombe ◽  
Genetic Control ◽  
Single Gene ◽  
Radiation Sensitivity ◽  
Cellular Repair ◽  
Repair Mechanisms ◽  
Radiation Induced

ABSTRACT Genetic analysis of a large number of radiation-sensitive mutants of S. pombe, isolated in different laboratories, showed that these isolates represent 22 non-allelic loci. The mutants were shown to fall into three distinct classes concerning response to UV and ionizing radiation, including two mutants which are primarily sensitive to ionizing radiation but not to UV. Single-gene mutants were crossed to obtain supersensitive double mutants. Such double mutants showed a marked increase in sensitivity to a variety of inactivating agents as compared to the parental strains. The isolation of three classes of radiation-sensitive mutants and the construction of double mutants implies the presence of multiple pathways in S. pombe for repair of radiation-induced damage. The bearing of these data on cellular repair mechanisms in eukaryotes is discussed.

scholarly journals Super-Resolution Radiation Biology: From Bio-Dosimetry towards Nano-Studies of DNA Repair Mechanisms

2021 ◽  
Author(s):  
Jin-Ho Lee ◽  
Michael Hausmann
Keyword(s):  
Dna Repair ◽  
Ionizing Radiation ◽  
Fluorescence Microscopy ◽  
Spatial Organization ◽  
Super Resolution ◽  
Biological Materials ◽  
Repair Processes ◽  
Repair Protein ◽  
Repair Mechanisms ◽  
Dna Strand

Past efforts in radiobiology, radio-biophysics, epidemiology and clinical research strongly contributed to the current understanding of ionizing radiation effects on biological materials like cells and tissues. It is well accepted that the most dangerous, radiation induced damages of DNA in the cell nucleus are double strand breaks, as their false rearrangements cause dysfunction and tumor cell proliferation. Therefore, cells have developed highly efficient and adapted ways to repair lesions of the DNA double strand. To better understand the mechanisms behind DNA strand repair, a variety of fluorescence microscopy based approaches are routinely used to study radiation responses at the organ, tissue and cellular level. Meanwhile, novel super-resolution fluorescence microscopy techniques have rapidly evolved and become powerful tools to study biological structures and bio-molecular (re-)arrangements at the nano-scale. In fact, recent investigations have increasingly demonstrated how super-resolution microscopy can be applied to the analysis of radiation damage induced chromatin arrangements and DNA repair protein recruitment in order to elucidate how spatial organization of damage sites and repair proteins contribute to the control of repair processes. In this chapter, we would like to start with some fundamental aspects of ionizing radiation, their impact on biological materials, and some standard radiobiology assays. We conclude by introducing the concept behind super-resolution radiobiology using single molecule localization microscopy (SMLM) and present promising results from recent studies that show an organized architecture of damage sites and their environment. Persistent homologies of repair clusters indicate a correlation between repair cluster topology and repair pathway at a given damage locus. This overview over recent investigations may motivate radiobiologists to consider chromatin architecture and spatial repair protein organization for the understanding of DNA repair processes.

scholarly journals The maintenance of genetic stability of embryonic and induced pluripotent stem cells during anticancer therapies

2017 ◽  
Vol 71 (0) ◽  
pp. 0-0
Author(s):  
Ewelina Stelcer ◽  
Magdalena Łukjanow ◽  
Wiktoria Maria Suchorska
Keyword(s):  
Stem Cells ◽  
Dna Repair ◽  
Regenerative Medicine ◽  
Ionizing Radiation ◽  
Genetic Stability ◽  
Excision Repair ◽  
Dna Repair Mechanisms ◽  
Differentiated Cells ◽  
Undifferentiated Cells ◽  
Repair Mechanisms

Regenerative medicine is a very rapidly developing discipline. Its progress contributes to elongated life expectancy and improved quality of life of patients suffering from so far incurable diseases. Stem cells (SCs) are undifferentiated cells that are able to undergo unlimited number of cell divisions and differentiation into specialized cells. Therapies based on SCs constitute a relatively new and promising approach in regenerative medicine. Radiotherapy is the most often used method in the treatment of cancer. In the future, the usage of SCs will be connected with the inevitable exposure of SCs to ionizing radiation during both treatment and diagnosis. The issue of genetic stability of SCs and cells differentiated from them is crucial, particularly regarding the application of these cells in clinical practice. It is important to emphasize that differentiated and undifferentiated cells possess different cell cycle, metabolism, initial level of reactive oxygen species, DNA repair mechanisms, susceptibility to apoptosis and frequency of mutations. All these factors contribute to the distinct radiosensitivity of SCs and differentiated cells. The aim of this study was to present the latest literature data concerning DNA repair mechanisms in pluripotent SCs (Homologous Recombination, Non-homologous End Joining, Mismatch Repair, Base Excision Repair and Nucleotide Excision Repair) in response to the influence of cyto- and genotoxic agents, such as ionizing radiation and chemotherapeutics. Evaluation the efficacy of DNA repair mechanisms is relevant for pluripotent SCs, because ineffective DNA repair mechanisms may result in the accumulation of mutations and, consequently, to cancer.

Radiation-induced surface decomposition

1983 ◽  
Vol 41 ◽  
pp. 368-369
Author(s):  
M. L. Knotek
Keyword(s):  
Ionizing Radiation ◽  
Atomic Structure ◽  
Chemical Bonding ◽  
Neutral Species ◽  
Radiation Induced ◽  
Physical And Chemical ◽  
Surface Decomposition ◽  
The Relationship ◽  
Electron And Photon ◽  
Surface Bond

Modern surface analysis is based largely upon the use of ionizing radiation to probe the electronic and atomic structure of the surfaces physical and chemical makeup. In many of these studies the ionizing radiation used as the primary probe is found to induce changes in the structure and makeup of the surface, especially when electrons are employed. A number of techniques employ the phenomenon of radiation induced desorption as a means of probing the nature of the surface bond. These include Electron- and Photon-Stimulated Desorption (ESD and PSD) which measure desorbed ionic and neutral species as they leave the surface after the surface has been excited by some incident ionizing particle. There has recently been a great deal of activity in determining the relationship between the nature of chemical bonding and its susceptibility to radiation damage.

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