Watson–Crick Base Pair Radical Cation as a Model for Oxidative Damage in DNA

2017 ◽  
Vol 8 (13) ◽  
pp. 3159-3165 ◽  
Author(s):  
Linda Feketeová ◽  
Bun Chan ◽  
George N. Khairallah ◽  
Vincent Steinmetz ◽  
Philippe Maitre ◽  
...  
Keyword(s):  
Oxidative Damage ◽  
Radical Cation ◽  
Base Pair

External electric field promotes proton transfer in the radical cation of adenine–thymine

2016 ◽  
Vol 30 (21) ◽  
pp. 1650276 ◽  
Author(s):  
Guiqing Zhang ◽  
Shijie Xie
Keyword(s):  
Electric Field ◽  
Proton Transfer ◽  
External Electric Field ◽  
Radical Cation ◽  
Base Pair ◽  
Low Temperatures ◽  
Room Temperature ◽  
Theoretical Calculations ◽  
Base Pairs ◽  
Adenine Thymine

According to [Formula: see text] measurements, it has been predicted that proton transfer would not occur in the radical cation of adenine–thymine (A:T). However, recent theoretical calculations indicate that proton transfer takes place in the base pair in water below the room temperature. We have performed simulations of proton transfer in the cation of B-DNA stack composed of 10 A:T base pairs in water from 20 K to 300 K. Proton transfer occurs below the room temperature, meanwhile it could also be observed at the room temperature under the external electric field. Another case that interests us is that proton transfer bounces back after [Formula: see text][Formula: see text]300 fs from the appearance of proton transfer at low temperatures.

Mass spectrometry and computational study of collision-induced dissociation of 9-methylguanine–1-methylcytosine base-pair radical cation: intra-base-pair proton transfer and hydrogen transfer, non-statistical dissociation, and reaction with a water ligand

2020 ◽  
Vol 22 (26) ◽  
pp. 14875-14888 ◽  
Author(s):  
Yan Sun ◽  
May Myat Moe ◽  
Jianbo Liu
Keyword(s):  
Mass Spectrometry ◽  
Proton Transfer ◽  
Radical Cation ◽  
Base Pair ◽  
Hydrogen Transfer ◽  
Theoretical Study ◽  
Computational Study ◽  
Collision Induced Dissociation ◽  
Water Ligand

A combined experimental and theoretical study is presented on the collision-induced dissociation of 9-methylguanine–1-methylcytosine base-pair radical cation ([9MG·1MC]˙+) and its monohydrate ([9MG·1MC]˙+·H2O) with Xe and Ar gases.

scholarly journals Effects of Stability of Base Pairs Containing an Oxazolone on DNA Elongation

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Masayo Suzuki ◽  
Kazuya Ohtsuki ◽  
Katsuhito Kino ◽  
Teruhiko Kobayashi ◽  
Masayuki Morikawa ◽  
...  
Keyword(s):  
Dna Replication ◽  
Oxidative Damage ◽  
Ab Initio ◽  
Base Pair ◽  
Thermal Denaturation ◽  
Primer Extension ◽  
Base Pairs ◽  
Nucleotide Incorporation ◽  
The Stability

The nucleoside 2,2,4-triamino-5(2H)-oxazolone (Oz) can result from oxidative damage to guanine residues in DNA. Despite differences among the three polymerases (Polβ, KF exo−, and Polη) regarding nucleotide incorporation patterns opposite Oz, all three polymerases can incorporate guanine opposite Oz. Based onab initiocalculations, we proposed a structure for a stable Oz:G base pair. Here, to assess the stability of each Oz-containing base pair (Oz:G, Oz:A, Oz:C, and Oz:T) upon DNA replication, we determined the efficiency of Polβ-, KF exo−-, or Polη-catalyzed primer extension beyond each base pair. With each polymerase, extension beyond Oz:G was more efficient than that beyond Oz:A, Oz:C, or Oz:T. Moreover, thermal denaturation studies revealed that theTmvalue for the duplex containing Oz:G was significantly higher than those obtained for duplexes containing Oz:A, Oz:C, or Oz:T. Therefore, the results fromab initiocalculations along with those from DNA replication assays and thermal denaturation experiments supported the conclusion that Oz:G is the most stable of the Oz-containing base pairs.

Erythrophagocytosis in the Liver in Hemolytic Anemias

1968 ◽  
Vol 26 ◽  
pp. 184-185
Author(s):  
O. T. Minick ◽  
E. Orfei ◽  
F. Volini ◽  
G. Kent
Keyword(s):  
Acid Phosphatase ◽  
Oxidative Damage ◽  
Phosphatase Activity ◽  
Kupffer Cells ◽  
Acid Phosphatase Activity ◽  
Common Type ◽  
Red Cell ◽  
Cell Fragments ◽  
Reticulo Endothelial System ◽  
Important Site

Hemolytic anemias were produced in rats by administering phenylhydrazine or anti-erythrocytic (rooster) serum, the latter having agglutinin and hemolysin titers exceeding 1:1000.Following administration of phenylhydrazine, the erythrocytes undergo oxidative damage and are removed from the circulation by the cells of the reticulo-endothelial system, predominantly by the spleen. With increasing dosage or if animals are splenectomized, the Kupffer cells become an important site of sequestration and are greatly hypertrophied. Whole red cells are the most common type engulfed; they are broken down in digestive vacuoles, as shown by the presence of acid phosphatase activity (Fig. 1). Heinz body material and membranes persist longer than native hemoglobin. With larger doses of phenylhydrazine, erythrocytes undergo intravascular fragmentation, and the particles phagocytized are now mainly red cell fragments of varying sizes (Fig. 2).

Protective effect of chitooligosaccharides on hydrogen peroxide-induced PC-12 cells death by inhibition of oxidative damage

2010 ◽  
Vol 34 (8) ◽  
pp. S27-S27
Author(s):  
Xueling Dai ◽  
Ping Chang ◽  
Ke Xu ◽  
Changjun Lin ◽  
Hanchang Huang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Oxidative Damage ◽  
Protective Effect ◽  
Pc 12 Cells ◽  
Cells Death

Aging and Oxidative Damage: Are Telomeres the Target?

2002 ◽  
Vol 7 (5) ◽  
pp. 295-313 ◽  
Author(s):  
Patricia A. McChesney ◽  
Lynne W. Elmore ◽  
Shawn E. Holt
Keyword(s):  
Oxidative Damage

Melatonin reduces high levels of lipid peroxidation induced by potassium iodate in porcine thyroid

2019 ◽  
pp. 1-7 ◽  
Author(s):  
Paulina Iwan ◽  
Jan Stepniak ◽  
Malgorzata Karbownik-Lewinska
Keyword(s):  
Lipid Peroxidation ◽  
Oxidative Damage ◽  
Membrane Lipids ◽  
Chemical Properties ◽  
Iodine Concentration ◽  
Free Radical Scavenger ◽  
Radical Scavenger ◽  
Protective Effects ◽  
Potassium Iodate ◽  
Hormone Synthesis

Abstract. Iodine is essential for thyroid hormone synthesis. Under normal iodine supply, calculated physiological iodine concentration in the thyroid is approx. 9 mM. Either potassium iodide (KI) or potassium iodate (KIO3) are used in iodine prophylaxis. KI is confirmed as absolutely safe. KIO3 possesses chemical properties suggesting its potential toxicity. Melatonin (N-acetyl-5-methoxytryptamine) is an effective antioxidant and free radical scavenger. Study aims: to evaluate potential protective effects of melatonin against oxidative damage to membrane lipids (lipid peroxidation, LPO) induced by KI or KIO3 in porcine thyroid. Homogenates of twenty four (24) thyroids were incubated in presence of either KI or KIO3 without/with melatonin (5 mM). As melatonin was not effective against KI-induced LPO, in the next step only KIO3 was used. Homogenates were incubated in presence of KIO3 (200; 100; 50; 25; 20; 15; 10; 7.5; 5.0; 2.5; 1.25 mM) without/with melatonin or 17ß-estradiol. Five experiments were performed with different concentrations of melatonin (5.0; 2.5; 1.25; 1.0; 0.625 mM) and one with 17ß-estradiol (1.0 mM). Malondialdehyde + 4-hydroxyalkenals (MDA + 4-HDA) concentration (LPO index) was measured spectrophotometrically. KIO3 increased LPO with the strongest damaging effect (MDA + 4-HDA level: ≈1.28 nmol/mg protein, p < 0.05) revealed at concentrations of around 15 mM, thus corresponding to physiological iodine concentrations in the thyroid. Melatonin reduced LPO (MDA + 4-HDA levels: from ≈0.97 to ≈0,76 and from ≈0,64 to ≈0,49 nmol/mg protein, p < 0.05) induced by KIO3 at concentrations of 10 mM or 7.5 mM. Conclusion: Melatonin can reduce very strong oxidative damage to membrane lipids caused by KIO3 used in doses resulting in physiological iodine concentrations in the thyroid.

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