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 Resistance of Bacillus subtilis Spore DNA to Lethal Ionizing Radiation Damage Relies Primarily on Spore Core Components and DNA Repair, with Minor Effects of Oxygen Radical Detoxification

2013 ◽  
Vol 80 (1) ◽  
pp. 104-109 ◽  
Author(s):  
Ralf Moeller ◽  
Marina Raguse ◽  
Günther Reitz ◽  
Ryuichi Okayasu ◽  
Zuofeng Li ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Repair ◽  
Bacillus Subtilis ◽  
Ionizing Radiation ◽  
High Energy ◽  
Oxygen Radical ◽  
Oxidative Stress Response ◽  
Iron Ions ◽  
Spore Resistance ◽  
Core Components

ABSTRACTThe roles of various core components, including α/β/γ-type small acid-soluble spore proteins (SASP), dipicolinic acid (DPA), core water content, and DNA repair by apurinic/apyrimidinic (AP) endonucleases or nonhomologous end joining (NHEJ), inBacillus subtilisspore resistance to different types of ionizing radiation including X rays, protons, and high-energy charged iron ions have been studied. Spores deficient in DNA repair by NHEJ or AP endonucleases, the oxidative stress response, or protection by major α/β-type SASP, DPA, and decreased core water content were significantly more sensitive to ionizing radiation than wild-type spores, with highest sensitivity to high-energy-charged iron ions. DNA repair via NHEJ and AP endonucleases appears to be the most important mechanism for spore resistance to ionizing radiation, whereas oxygen radical detoxification via the MrgA-mediated oxidative stress response or KatX catalase activity plays only a very minor role. Synergistic radioprotective effects of α/β-type but not γ-type SASP were also identified, indicating that α/β-type SASP's binding to spore DNA is important in preventing DNA damage due to reactive oxygen species generated by ionizing radiation.

scholarly journals Role of DNA Repair by Nonhomologous-End Joining in Bacillus subtilis Spore Resistance to Extreme Dryness, Mono- and Polychromatic UV, and Ionizing Radiation

2007 ◽  
Vol 189 (8) ◽  
pp. 3306-3311 ◽  
Author(s):  
Ralf Moeller ◽  
Erko Stackebrandt ◽  
Günther Reitz ◽  
Thomas Berger ◽  
Petra Rettberg ◽  
...  
Keyword(s):  
Dna Repair ◽  
Bacillus Subtilis ◽  
Ionizing Radiation ◽  
Ultrahigh Vacuum ◽  
Nonhomologous End Joining ◽  
Wild Type ◽  
Dna Double Strand Breaks ◽  
End Joining ◽  
Spore Resistance

ABSTRACT The role of DNA repair by nonhomologous-end joining (NHEJ) in spore resistance to UV, ionizing radiation, and ultrahigh vacuum was studied in wild-type and DNA repair mutants (recA, splB, ykoU, ykoV, and ykoU ykoV mutants) of Bacillus subtilis. NHEJ-defective spores with mutations in ykoU, ykoV, and ykoU ykoV were significantly more sensitive to UV, ionizing radiation, and ultrahigh vacuum than wild-type spores, indicating that NHEJ provides an important pathway during spore germination for repair of DNA double-strand breaks.

scholarly journals Take a Break to Repair: A Dip in the World of Double-Strand Break Repair Mechanisms Pointing the Gaze on Archaea

2021 ◽  
Vol 22 (24) ◽  
pp. 13296
Author(s):  
Mariarosaria De Falco ◽  
Mariarita De Felice
Keyword(s):  
Cell Cycle ◽  
Dna Repair ◽  
Genome Stability ◽  
Developmental Disorders ◽  
Strand Break ◽  
Human Diseases ◽  
Dna Damages ◽  
Dna Repair Mechanisms ◽  
Repair Mechanisms ◽  
Repair Pathways

All organisms have evolved many DNA repair pathways to counteract the different types of DNA damages. The detection of DNA damage leads to distinct cellular responses that bring about cell cycle arrest and the induction of DNA repair mechanisms. In particular, DNA double-strand breaks (DSBs) are extremely toxic for cell survival, that is why cells use specific mechanisms of DNA repair in order to maintain genome stability. The choice among the repair pathways is mainly linked to the cell cycle phases. Indeed, if it occurs in an inappropriate cellular context, it may cause genome rearrangements, giving rise to many types of human diseases, from developmental disorders to cancer. Here, we analyze the most recent remarks about the main pathways of DSB repair with the focus on homologous recombination. A thorough knowledge in DNA repair mechanisms is pivotal for identifying the most accurate treatments in human diseases.

scholarly journals The roles of RNA in DNA double-strand break repair

2020 ◽  
Vol 122 (5) ◽  
pp. 613-623 ◽  
Author(s):  
Aldo S. Bader ◽  
Ben R. Hawley ◽  
Ania Wilczynska ◽  
Martin Bushell
Keyword(s):  
Dna Repair ◽  
Cancer Progression ◽  
Genome Stability ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Critical Role ◽  
Strand Break ◽  
Rna Molecules ◽  
Repair Mechanisms ◽  
Recent Developments

AbstractEffective DNA repair is essential for cell survival: a failure to correctly repair damage leads to the accumulation of mutations and is the driving force for carcinogenesis. Multiple pathways have evolved to protect against both intrinsic and extrinsic genotoxic events, and recent developments have highlighted an unforeseen critical role for RNA in ensuring genome stability. It is currently unclear exactly how RNA molecules participate in the repair pathways, although many models have been proposed and it is possible that RNA acts in diverse ways to facilitate DNA repair. A number of well-documented DNA repair factors have been described to have RNA-binding capacities and, moreover, screens investigating DNA-damage repair mechanisms have identified RNA-binding proteins as a major group of novel factors involved in DNA repair. In this review, we integrate some of these datasets to identify commonalities that might highlight novel and interesting factors for future investigations. This emerging role for RNA opens up a new dimension in the field of DNA repair; we discuss its impact on our current understanding of DNA repair processes and consider how it might influence cancer progression.

Effect of intercalation in graphite epoxy composites on the shielding of high energy radiation

1998 ◽  
Vol 13 (8) ◽  
pp. 2297-2301 ◽  
Author(s):  
James R. Gaier ◽  
Wendie C. Hardebeck ◽  
Jennifer R. Terry Bunch ◽  
Michelle L. Davidson ◽  
Dwight B. Beery
Keyword(s):  
Ionizing Radiation ◽  
Absorption Coefficient ◽  
Inelastic Scattering ◽  
High Energy ◽  
Mass Absorption Coefficient ◽  
Epoxy Composites ◽  
X Rays ◽  
Mass Absorption ◽  
Iodine Monobromide ◽  
Half Thickness

The half-thickness and mass absorption coefficient of 13.0 keV x-rays, 46.5 keV γ-rays, and 1.16 MeV βƟ particles have been measured for pristine, bromine intercalated, and iodine monobromide intercalated pitch-based graphite fiber composites. Since these materials have been proposed to replace aluminum structures in spacecraft, the results were compared to aluminum. Pristine graphite epoxy composites were found to have about 4.0 times the half-thickness, and 40% of the mass absorption of aluminum for ionizing radiation. Bromine intercalation improved performance to 90% of the half-thickness, and 1.7 times the mass absorption coefficient of aluminum. Iodine monobromide extended the performance to 70% of the half-thickness and 3.0 times the mass absorption of aluminum. Thus, intercalation not only makes up the deficiency conventional composites have in shielding components from ionizing radiation, but actually confers advantages in mass and thickness over aluminum. The βƟ particle shielding of all the materials tested was found to be very effective. The shielding of all of the materials was found to have nearly the same mass absorption coefficient of 17.8 ± 0.9 cm2/g. Inelastic scattering processes were found to be important in βƟ particle shielding; however, the extent of inelastic scattering and thus the distribution of energies of the transmitted electrons did not vary with material.

scholarly journals A hyperactive variant of theEscherichia colianaerobic transcription factor FNR enhances ionizing radiation resistance

2018 ◽  
Author(s):  
Steven T. Bruckbauer ◽  
Joseph D. Trimarco ◽  
Elizabeth A. Wood ◽  
John R. Battista ◽  
Michael M. Cox
Keyword(s):  
Dna Repair ◽  
Transcription Factor ◽  
Ionizing Radiation ◽  
Anaerobic Metabolism ◽  
Strand Break ◽  
Cell Wall Metabolism ◽  
Dna Double Strand Break ◽  
Replication Restart ◽  
Dna Repair Proteins ◽  
Ionizing Radiation Resistance

AbstractWe have previously generated four replicate populations of ionizing radiation (IR)- resistantEscherichia colithough directed evolution. Sequencing of isolates from these populations revealed that mutations affecting DNA repair (through DNA double-strand break repair and replication restart), ROS amelioration, and cell wall metabolism were prominent. Three mutations involved in DNA repair explained the IR resistance phenotype in one population, and similar DNA repair mutations were prominent in two others. The remaining population, IR-3-20, had no mutations in the key DNA repair proteins, suggesting that it had taken a different evolutionary path to IR resistance. Here, we present evidence that a variant of the anaerobic metabolism transcription factor FNR isolated from population IR-3-20 can play a role in IR resistance. An FNR variant is unique to IR-3-20 and suggests a role for altered global metabolism through the FNR regulon as a means for experimentally-evolved IR resistance.

scholarly journals Recombineering in C. elegans: genome editing using in vivo assembly of linear DNAs

2016 ◽  
Author(s):  
Alexandre Paix ◽  
Helen Schmidt ◽  
Geraldine Seydoux
Keyword(s):  
Dna Repair ◽  
Homologous Recombination ◽  
Genome Editing ◽  
Strand Break ◽  
Double Strand Break ◽  
Template Switching ◽  
C Elegans ◽  
Repair Mechanisms

ABSTRACTRecombineering, the use of endogenous homologous recombination systems to recombine DNA in vivo, is a commonly used technique for genome editing in microbes. Recombineering has not yet been developed for animals, where non-homology-based mechanisms have been thought to dominate DNA repair. Here, we demonstrate that homology-dependent repair (HDR) is robust in C. elegans using linear templates with short homologies (~35 bases). Templates with homology to only one side of a double-strand break initiate repair efficiently, and short overlaps between templates support template switching. We demonstrate the use of single-stranded, bridging oligonucleotides (ssODNs) to target PCR fragments precisely to DSBs induced by CRISPR/Cas9 on chromosomes. Based on these findings, we develop recombineering strategies for genome editing that expand the utility of ssODNs and eliminate in vitro cloning steps for template construction. We apply these methods to the generation of GFP knock-in alleles and gene replacements without co-integrated markers. We conclude that, like microbes, metazoans possess robust homology-dependent repair mechanisms that can be harnessed for recombineering and genome editing.

scholarly journals Comparison of Responses to Double-Strand Breaks between Escherichia coli and Bacillus subtilis Reveals Different Requirements for SOS Induction

2008 ◽  
Vol 191 (4) ◽  
pp. 1152-1161 ◽  
Author(s):  
Lyle A. Simmons ◽  
Alexi I. Goranov ◽  
Hajime Kobayashi ◽  
Bryan W. Davies ◽  
Daniel S. Yuan ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Bacillus Subtilis ◽  
Ionizing Radiation ◽  
Strand Break ◽  
Double Strand Break ◽  
Double Strand Breaks ◽  
Double Strand Break Repair ◽  
Strand Breaks ◽  
E Coli ◽  
Sos Induction

ABSTRACT DNA double-strand breaks are particularly deleterious lesions that can lead to genomic instability and cell death. We investigated the SOS response to double-strand breaks in both Escherichia coli and Bacillus subtilis. In E. coli, double-strand breaks induced by ionizing radiation resulted in SOS induction in virtually every cell. E. coli strains incapable of SOS induction were sensitive to ionizing radiation. In striking contrast, we found that in B. subtilis both ionizing radiation and a site-specific double-strand break causes induction of prophage PBSX and SOS gene expression in only a small subpopulation of cells. These results show that double-strand breaks provoke global SOS induction in E. coli but not in B. subtilis. Remarkably, RecA-GFP focus formation was nearly identical following ionizing radiation challenge in both E. coli and B. subtilis, demonstrating that formation of RecA-GFP foci occurs in response to double-strand breaks but does not require or result in SOS induction in B. subtilis. Furthermore, we found that B. subtilis cells incapable of inducing SOS had near wild-type levels of survival in response to ionizing radiation. Moreover, B. subtilis RecN contributes to maintaining low levels of SOS induction during double-strand break repair. Thus, we found that the contribution of SOS induction to double-strand break repair differs substantially between E. coli and B. subtilis.

Burns by Ionizing and Non-Ionizing Radiation

2020 ◽  
Author(s):  
Giovanni Alcocer ◽  
Priscilla Alcocer ◽  
Carlos Marquez
Keyword(s):  
Ionizing Radiation ◽  
Visible Light ◽  
Gamma Rays ◽  
Biological Effects ◽  
High Energy ◽  
Low Energy ◽  
X Rays ◽  
Nuclear Accidents ◽  
Diagnostic Equipment ◽  
Nonionizing Radiation

Abstract This article consists of the study and investigative analysis of the effects of burns by radiation in humans. Cases of nuclear accidents, such as Chernobyl (ionizing radiation) and the effects of non-ionizing radiation such as infrared and microwave radiation are detailed. It is examined cases of injuries and burns by ionizing radiation due to irradiation (diagnostic equipment and medical treatment: X-rays, radiotherapy) or contamination (nuclear accidents, wars). Injuries and burns are also caused by nonionizing radiation, such as visible light (laser), ultraviolet, radiofrequency. There are numerous biological issues in the case of tissues, the ionizing radiation (ionizing particles and electromagnetic radiation: X-rays, gamma rays and high energy ultraviolet) can cause damage mainly in the DNA. This can cause mutations in its genetic code and cancer 5. In addition, damage to other tissues and organs can occur, as well as burns, erythema and lesions. The biological effects of nonionizing radiation are currently under investigation. Burns, erythema and lesions can also occur due to the following types of radiation: low energy ultraviolet, visible light, infrared, microwave, radiofrequency, electromagnetic fields. The purpose of this article is to provide an exhaustive analysis of all types of both ionizing and non-ionizing radiation and their effects on living beings. Finally, it is important to follow all safety and radiation protections against both ionizing and non-ionizing radiation.

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.

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