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Fertility and Sterility Sep 2016
Topics: Body Fluids; Humans; Oxidation-Reduction; Semen; Sperm Motility
PubMed: 27327392
DOI: 10.1016/j.fertnstert.2016.06.014 -
Environmental Health Perspectives Feb 1995Several metal or metalloid ions exist in multiple oxidation states and can undergo electron transfer reactions that are important in biological and environmental...
Several metal or metalloid ions exist in multiple oxidation states and can undergo electron transfer reactions that are important in biological and environmental systems. There are endogenous metal ions such as iron, copper, and cobalt that participate in oxidation-reduction reactions with species of oxygen like molecular dioxygen, superoxide, and hydrogen peroxide. These reactions may be modulated by endogenous reducing agents such as glutathione, ascorbate, and tocopherol. The reactions can be described in terms of thermodynamics through the use of standard electrode potentials. A favorable reaction will depend on the concentrations of the reactants and may depend on the pH and/or on the presence of organic ligands that form complexes with the metal or metalloid. Arsenate (As(V)) can react with glutathione in buffered aqueous solutions to produce arsenite (As(III)) and oxidized glutathione. This reaction may be important in the methylation reactions of arsenic. Arsenic species can decrease the red blood cell levels of reduced glutathione, but the products of oxidation and the mechanism of oxidation are more complex than those found in water alone. Chromium (VI) is thought to interact with DNA after first reacting with a reducing agent such as glutathione to form lower oxidation states of chromium. These examples illustrate the importance of oxidation-reduction reactions for toxic metals and metalloids.
Topics: Carcinogens, Environmental; Electron Transport; Humans; Hydrogen-Ion Concentration; Ions; Metals; Oxidation-Reduction; Potentiometry; Reference Standards
PubMed: 7621791
DOI: 10.1289/ehp.95103s117 -
Molecules (Basel, Switzerland) Nov 2014All forms of life maintain a reducing environment (homeostasis) within their cells. Perturbations in the normal redox state can lead to an oxidative environment which... (Review)
Review
All forms of life maintain a reducing environment (homeostasis) within their cells. Perturbations in the normal redox state can lead to an oxidative environment which has deleterious effects, especially in health. In biological systems, metabolic activities are dependent mainly on mitochondrial oxidative phosphorylation, a metabolic pathway that uses energy released by the oxidation of nutrients to produce ATP. In the process of oxidative phosphorylation, electrons are transferred from electron donors to electron acceptors such as oxygen in redox reactions and often results to the generation of reactive species. Reactive oxygen species consist of a class of radical and non-radical oxygen derivatives. The imbalance between the reactive oxygen species and antioxidant defence systems leads to oxidative burden and hence, damage biological molecules. Antioxidants help to prevent or fix the deleterious effects of reactive species. Sulfur is an important element in biological systems. This atom is usually integrated into proteins as the redox-active cysteine residue and in molecules such as glutathione, thioredoxin and glutaredoxin which are vital antioxidant molecules and are therefore essential for life. This review covers the role of sulfur containing antioxidant systems in oxidative environments.
Topics: Antioxidants; Oxidation-Reduction; Sulfur; Sulfur Compounds
PubMed: 25429562
DOI: 10.3390/molecules191219376 -
Journal of Biomedicine & Biotechnology 2012During the past decades, it became obvious that reactive oxygen species (ROS) exert a multitude of biological effects covering a wide spectrum that ranges from... (Review)
Review
During the past decades, it became obvious that reactive oxygen species (ROS) exert a multitude of biological effects covering a wide spectrum that ranges from physiological regulatory functions to damaging alterations participating in the pathogenesis of increasing number of diseases. This review summarizes the key roles played by the ROS in both health and disease. ROS are metabolic products arising from various cells; two cellular organelles are intimately involved in their production and metabolism, namely, the endoplasmic reticulum and the mitochondria. Updates on research that tremendously aided in confirming the fundamental roles of both organelles in redox regulation will be discussed as well. Although not comprehensive, this review will provide brief perspective on some of the current research conducted in this area for better understanding of the ROS actions in various conditions of health and disease.
Topics: Animals; Antioxidants; Disease; Health; Humans; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species
PubMed: 22927725
DOI: 10.1155/2012/936486 -
Free Radical Biology & Medicine 1990Published experimental data pertaining to the participation of coenzyme Q as a site of free radical formation in the mitochondrial electron transfer chain and the... (Review)
Review
Published experimental data pertaining to the participation of coenzyme Q as a site of free radical formation in the mitochondrial electron transfer chain and the conditions required for free radical production have been reviewed critically. The evidence suggests that a component from each of the mitochondrial NADH-coenzyme Q, succinate-coenzyme Q, and coenzyme QH2-cytochrome c reductases (complexes I, II, and III), most likely a nonheme iron-sulfur protein of each complex, is involved in free radical formation. Although the semiquinone form of coenzyme Q may be formed during electron transport, its unpaired electron most likely serves to aid in the dismutation of superoxide radicals instead of participating in free radical formation. Results of studies with electron transfer chain inhibitors make the conclusion dubious that coenzyme Q is a major free radical generator under normal physiological conditions but may be involved in superoxide radical formation during ischemia and subsequent reperfusion. Experiments at various levels of organization including subcellular systems, intact animals, and human subjects in the clinical setting, support the view that coenzyme Q, mainly in its reduced state, may act as an antioxidant protecting a number of cellular membranes from free radical damage.
Topics: Animals; Antioxidants; Electron Transport; Free Radicals; Humans; Mitochondria; Oxidation-Reduction; Ubiquinone
PubMed: 2193854
DOI: 10.1016/0891-5849(90)90154-b -
International Journal of Molecular... Sep 2019From their discovery in biological systems, reactive oxygen species (ROS) have been considered key players in tissue injury for their capacity to oxidize biological...
From their discovery in biological systems, reactive oxygen species (ROS) have been considered key players in tissue injury for their capacity to oxidize biological macromolecules [...].
Topics: Animals; Antioxidants; Humans; Oxidation-Reduction; Oxidative Stress; Reactive Oxygen Species
PubMed: 31569717
DOI: 10.3390/ijms20194810 -
Arhiv Za Higijenu Rada I Toksikologiju Jun 2018Pesticides are a highly diverse group of compounds and the most important chemical stressors in the environment. Mechanisms that could explain pesticide toxicity are... (Review)
Review
Pesticides are a highly diverse group of compounds and the most important chemical stressors in the environment. Mechanisms that could explain pesticide toxicity are constantly being studied and their interactions at the cellular level are often observed in well-controlled in vitro studies. Several pesticide groups have been found to impair the redox balance in the cell, but the mechanisms leading to oxidative stress for certain pesticides are only partly understood. As our scientific project "Organic pollutants in environment - markers and biomarkers of toxicity (OPENTOX)" is dedicated to studying toxic effects of selected insecticides and herbicides, this review is focused on reporting the knowledge regarding oxidative stress-related phenomena at the cellular level. We wanted to single out the most important facts relevant to the evaluation of our own findings from studies conducted on in vitro cell models.
Topics: Animals; Biomarkers; Cell Enlargement; Cell Proliferation; In Vitro Techniques; Oxidation-Reduction; Oxidative Stress; Pesticides
PubMed: 29990294
DOI: 10.2478/aiht-2018-69-3105 -
Oxidative Medicine and Cellular... 2017
Topics: Animals; Antioxidants; Brain Diseases; Dietary Supplements; Humans; Oxidation-Reduction
PubMed: 28529676
DOI: 10.1155/2017/5048432 -
Oxidative Medicine and Cellular... 2014
Topics: Aging; Humans; Lipid Peroxidation; Neurodegenerative Diseases; Neuroprotective Agents; Oxidation-Reduction; Oxidative Stress
PubMed: 24778767
DOI: 10.1155/2014/270291 -
Scientific Reports Jan 2017This systematic experimental investigation reveals that high-frequency ultrasound irradiation (550 kHz) induced oxidation of D-glucose to glucuronic acid in excellent...
This systematic experimental investigation reveals that high-frequency ultrasound irradiation (550 kHz) induced oxidation of D-glucose to glucuronic acid in excellent yield without assistance of any (bio)catalyst. Oxidation is induced thanks to the in situ production of radical species in water. Experiments show that the dissolved gases play an important role in governing the nature of generated radical species and thus the selectivity for glucuronic acid. Importantly, this process yields glucuronic acid instead of glucuronate salt typically obtained via conventional (bio)catalyst routes, which is of huge interest in respect of downstream processing. Investigations using disaccharides revealed that radicals generated by high frequency ultrasound were also capable of promoting tandem hydrolysis/oxidation reactions.
Topics: Carbohydrates; Catalysis; Chromatography, High Pressure Liquid; Gas Chromatography-Mass Spectrometry; Glucose; Glucuronic Acid; Oxidation-Reduction; Solutions; Ultrasonic Waves
PubMed: 28084448
DOI: 10.1038/srep40650