A Single Nuclease-Resistant Linkage in DNA as a Versatile Tool for the Characterization of DNA Lesions: Application to the Guanine Oxidative Lesion “G+34” Generated by Metalloporphyrin/KHSO5 Reagent

2012 ◽  
Vol 25 (11) ◽  
pp. 2505-2512 ◽  
Author(s):  
Agnieszka Tomaszewska ◽  
Sophie Mourgues ◽  
Piotr Guga ◽  
Barbara Nawrot ◽  
Geneviève Pratviel
Keyword(s):  
Dna Lesions ◽  
Versatile Tool ◽  
G 34

scholarly journals The memory effect of nanoscale memristors investigated by conducting scanning probe microscopy methods

2012 ◽  
Vol 3 ◽  
pp. 722-730 ◽  
Author(s):  
César Moreno ◽  
Carmen Munuera ◽  
Xavier Obradors ◽  
Carmen Ocal
Keyword(s):  
Memory Effect ◽  
Scanning Probe Microscopy ◽  
Electrical Characterization ◽  
Scanning Force Microscopy ◽  
Scanning Probe ◽  
Force Microscopy ◽  
Versatile Tool ◽  
Scanning Force ◽  
Memristor Device

We report on the use of scanning force microscopy as a versatile tool for the electrical characterization of nanoscale memristors fabricated on ultrathin La0.7Sr0.3MnO3 (LSMO) films. Combining conventional conductive imaging and nanoscale lithography, reversible switching between low-resistive (ON) and high-resistive (OFF) states was locally achieved by applying voltages within the range of a few volts. Retention times of several months were tested for both ON and OFF states. Spectroscopy modes were used to investigate the I–V characteristics of the different resistive states. This permitted the correlation of device rectification (reset) with the voltage employed to induce each particular state. Analytical simulations by using a nonlinear dopant drift within a memristor device explain the experimental I–V bipolar cycles.

scholarly journals Characterization of the interplay between DNA repair and CRISPR/Cas9-induced DNA lesions at an endogenous locus

2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Anne Bothmer ◽  
Tanushree Phadke ◽  
Luis A. Barrera ◽  
Carrie M Margulies ◽  
Christina S. Lee ◽  
...  
Keyword(s):  
Dna Repair ◽  
Dna Lesions ◽  
Endogenous Locus

Constraint Manifold Synthesis of Planar Linkages

1996 ◽  
Author(s):  
A. P. Murray ◽  
J. M. McCarthy
Keyword(s):  
Design Theory ◽  
Geometric Constraints ◽  
Design Parameters ◽  
Design Problems ◽  
Constraint Manifold ◽  
Linkage Design ◽  
Versatile Tool ◽  
Algebraic Constraints ◽  
Planar Linkages

Abstract This paper formulates the design theory of planar four-bar linkages using the planar form of dual quaternions known as planar quaternions. The set of positions reachable by the floating link of a dyad is a quadratic algebraic surface called a constraint manifold. Determining the coefficients of the quadratic form defining this manifold is equivalent to setting the design parameters of the linkage. If the task of the linkage is specified as geometric constraints on the location of the floating link, then algebraic constraints are obtained on the quaternion components. We seek the coefficients of the constraint manifold that satisfies these constraints. The result is an algebraic formulation that is symmetric in its characterization of the linkage and task, and provides a versatile tool for the formulation and solution of linkage design problems.

scholarly journals Formation of cytosine glycol and 5,6-dihydroxycytosine in deoxyribonucleic acid on treatment with osmium tetroxide

1986 ◽  
Vol 235 (2) ◽  
pp. 531-536 ◽  
Author(s):  
M Dizdaroglu ◽  
E Holwitt ◽  
M P Hagan ◽  
W F Blakely
Keyword(s):  
Dna Repair ◽  
Formic Acid ◽  
Excision Repair ◽  
Dna Lesions ◽  
Gas Chromatography Mass Spectrometry ◽  
Dna Glycosylases ◽  
Thymine Glycol ◽  
Repair Enzymes ◽  
Base Excision

OsO4 selectively forms thymine glycol lesions in DNA. In the past, OsO4-treated DNA has been used as a substrate in studies of DNA repair utilizing base-excision repair enzymes such as DNA glycosylases. There is, however, no information available on the chemical identity of other OsO4-induced base lesions in DNA. A complete knowledge of such DNA lesions may be of importance for repair studies. Using a methodology developed recently for characterization of oxidative base damage in DNA, we provide evidence for the formation of cytosine glycol and 5,6-dihydroxycytosine moieties, in addition to thymine glycol, in DNA on treatment with OsO4. For this purpose, samples of OsO4-treated DNA were hydrolysed with formic acid, then trimethylsilylated and analysed by capillary gas chromatography-mass spectrometry. In addition to thymine glycol, 5-hydroxyuracil (isobarbituric acid), 5-hydroxycytosine and 5,6-dihydroxyuracil (isodialuric acid or dialuric acid) were identified in OsO4-treated DNA. It is suggested that 5-hydroxyuracil was formed by formic acid-induced deamination and dehydration of cytosine glycol, which was the actual oxidation product of the cytosine moiety in DNA. 5-Hydroxycytosine obviously resulted from dehydration of cytosine glycol, and 5,6-dihydroxyuracil from deamination of 5,6-dihydroxycytosine. This scheme was supported by the presence of 5-hydroxyuracil, uracil glycol and 5,6-dihydroxyuracil in OsO4-treated cytosine. Treatment of OsO4-treated cytosine with formic acid caused the complete conversion of uracil glycol into 5-hydroxyuracil. The implications of these findings relative to studies of DNA repair are discussed.

PURE AND MOSAIC CLONES — A REFLECTION OF DIFFERENCES IN MECHANISMS OF MUTAGENESIS BY DIFFERENT AGENTS IN SACCHAROMYCES CEREVISIAE

1981 ◽  
Vol 23 (1) ◽  
pp. 73-79 ◽  
Author(s):  
A. Nasim ◽  
M. A. Hannan ◽  
Earle R. Nestmann
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ultraviolet Light ◽  
Nitrous Acid ◽  
Repair Process ◽  
Dna Lesions ◽  
Ethyl Methanesulfonate ◽  
Methyl Methanesulfonate ◽  
Mechanisms Of Mutagenesis ◽  
G1 Cells

The induction of pure and mosaic clones has been studied in haploid G1 cells of Saccharomyces cerevisiae. Following treatments with ultraviolet light, methyl methanesulfonate, ethyl methanesulfonate, nitrous acid, and N-methyl-N′-nitro-N-nitrosoguanidine, the relative proportions of pure mutant clones varied from 25 to 100% at comparable survival levels. Ultraviolet light and methyl methanesulfonate produced mainly pure mutant clones, whereas ethyl methanesulfonate and nitrous acid produced mainly mosaics at 59 to 100% survival levels. The ratio of pure to mosaic clones induced by nitrosoguanidine fell between these two classes. These results are consistent with a classification of mutagens on the basis of repair and replication-dependent mechanisms of mutagenesis in other organisms. Agents having actions similar to ultraviolet light may produce mainly pure clones through a pre-replicative process involving an error-prone DNA repair process. Others may produce mainly mosaic mutants due to the different nature of DNA lesions which may require a replication-dependent process for fixation of mutations. Preliminary data from combined treatments of mutagens belonging to two different classes (i.e. ultraviolet light and nitrous acid) suggest the possibility of an interaction between these agents, resulting in a higher proportion of pure clones, possibly due to an inducible process. Studies of induced frequencies of pure and mosaic clones may be useful in the characterization of mutagens with functional differences.

Electron Holography, a Versatile Tool for Characterization of Materials: Fluoroapatite-Gelatine-Composites, SiC and SiO2

2005 ◽  
Vol 631 (6-7) ◽  
pp. 983-992 ◽  
Author(s):  
Paul Simon ◽  
Hannes Lichte ◽  
Damian M�nter ◽  
Wladimir Reschetilowski ◽  
Anibal Valera ◽  
...  
Keyword(s):  
Electron Holography ◽  
Versatile Tool ◽  
Characterization Of Materials

scholarly journals A multiplex serological assay for the characterization of IgG immune response to SARS-CoV-2

2021 ◽  
Author(s):  
Etienne Brochot ◽  
Vianney Souplet ◽  
Pauline Follet ◽  
Pauline Ponthieu ◽  
Christophe Olivier ◽  
...  
Keyword(s):  
Immune Response ◽  
Neutralizing Antibody ◽  
Viral Epitope ◽  
Time Period ◽  
Versatile Tool ◽  
Comprehensive Picture ◽  
Long Time ◽  
Antibody Titers ◽  
Combined Detection

Background: In the fight against SARS-COV-2, the development of serological assays based on different antigenic domains represent a versatile tool to get a comprehensive picture of the immune response or differentiate infection from vaccination beyond simple diagnosis. Objectives: Here we use a combination of the Nucleoprotein (NP), the Spike 1 (S1) and Spike 2 (S2) subunits, and the receptor binding domain (RBD) and N-terminal domain (NTD) of the Spike antigens from the Syrius-CoViDiag multiplex IgG assay, to follow the immune response to SARS-CoV-2 infection over a long time period and depending on disease severity. Results: Using a panel of 209 sera collected from 61 patients up to eight months after infection, we observed that most patients develop an immune response against multiple viral epitope, but anti-S2 antibodies seemed to last longer. For all the tested IgGs, we have found higher titers for hospitalized patients than for non-hospitalized ones. Moreover the combination of the five different IgG titers increased the correlation to the neutralizing antibody titers than if considered individually. Conclusion: Multiplex immunoassays have the potential to improve diagnostic performances, especially for ancient infection or mild form of the disease presenting weaker antibody titers. Also the combined detection of anti-NP and anti-Spike-derived domains can be useful to differentiate vaccination from viral infection and accurately assess the antibody potential to neutralize the virus.

scholarly journals Histone dynamics during DNA replication stress

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Chia-Ling Hsu ◽  
Shin Yen Chong ◽  
Chia-Yeh Lin ◽  
Cheng-Fu Kao
Keyword(s):  
Stress Responses ◽  
Genome Stability ◽  
Genome Instability ◽  
Replication Stress ◽  
Dna Lesions ◽  
Protective Mechanisms ◽  
Replication Process ◽  
Dna Replication Stress ◽  
External Sources

AbstractAccurate and complete replication of the genome is essential not only for genome stability but also for cell viability. However, cells face constant threats to the replication process, such as spontaneous DNA modifications and DNA lesions from endogenous and external sources. Any obstacle that slows down replication forks or perturbs replication dynamics is generally considered to be a form of replication stress, and the past decade has seen numerous advances in our understanding of how cells respond to and resolve such challenges. Furthermore, recent studies have also uncovered links between defects in replication stress responses and genome instability or various diseases, such as cancer. Because replication stress takes place in the context of chromatin, histone dynamics play key roles in modulating fork progression and replication stress responses. Here, we summarize the current understanding of histone dynamics in replication stress, highlighting recent advances in the characterization of fork-protective mechanisms.

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