-
Journal of Assisted Reproduction and... Jun 2017Oxidative stress is a well-established cause of male infertility, with reactive oxygen species (ROS) impairing sperm production, motility, membrane, and DNA integrity.... (Review)
Review
Oxidative stress is a well-established cause of male infertility, with reactive oxygen species (ROS) impairing sperm production, motility, membrane, and DNA integrity. Currently, most clinics do not test infertile patients for the imbalance between ROS generation and the ability of the antioxidants to scavenge them, although there is a clear need for andrology laboratories to be able to identify and/or quantify seminal oxidative stress. As such there is a clinical urgency for an inexpensive and easy-to-perform assay able to identify oxidative stress in semen. The aim of this review is to provide information on the currently available methods to assess and quantify ROS and particularly superoxide in male reproductive cells, tissues, and fluids which may have a significant clinical utility in identifying men with impaired fertility associated with oxidative stress. Through a deeper understanding of oxidative stress and its assessment options, clinical andrology labs may better assist patients to achieve increased rates of fertility and pregnancy.
Topics: Female; Free Radicals; Humans; Infertility, Male; Male; Oxidative Stress; Pregnancy; Reactive Oxygen Species; Semen; Semen Analysis; Superoxides
PubMed: 28341974
DOI: 10.1007/s10815-017-0912-8 -
Chemical Reviews Apr 2014
Review
Topics: Biocatalysis; Catalytic Domain; Hydrogen-Ion Concentration; Kinetics; Oxidoreductases; Superoxide Dismutase; Superoxides
PubMed: 24684599
DOI: 10.1021/cr4005296 -
Biochimica Et Biophysica Acta.... Oct 2022The superoxide anion - molecular oxygen reduced by a single electron - is produced in large amounts by enzymatic and adventitious reactions. It can perform a range of...
The superoxide anion - molecular oxygen reduced by a single electron - is produced in large amounts by enzymatic and adventitious reactions. It can perform a range of cellular functions, including bacterial warfare and iron uptake, signalling and host immune response in eukaryotes. However, it also serves as precursor for more deleterious species such as the hydroxyl anion or peroxynitrite and defense mechanisms to neutralize superoxide are important for cellular health. In addition to the soluble proteins superoxide dismutase and superoxide reductase, recently the membrane embedded diheme cytochrome b (CybB) from E. coli has been proposed to act as a superoxide:quinone oxidoreductase. Here, we confirm superoxide and cellular ubiquinones or menaquinones as natural substrates and show that quinone binding to the enzyme accelerates the reaction with superoxide. The reactivity of the substrates is in accordance with the here determined midpoint potentials of the two b hemes (+48 and -23 mV / NHE). Our data suggest that the enzyme can work near the diffusion limit in the forward direction and can also catalyse the reverse reaction efficiently under physiological conditions. The data is discussed in the context of described cytochrome b proteins and potential physiological roles of CybB.
Topics: Bacteria; Cytochromes b; Escherichia coli; Oxidoreductases; Superoxides
PubMed: 35671795
DOI: 10.1016/j.bbabio.2022.148583 -
Frontiers in Bioscience (Landmark... Jan 2009In this review some aspects of free radical theory of aging are discussed. Many new and interesting findings concerning the role of physiological free radicals... (Review)
Review
In this review some aspects of free radical theory of aging are discussed. Many new and interesting findings concerning the role of physiological free radicals superoxide and nitric oxide in senescence and aging development are considered and the mechanisms of processes mediated by these radicals are discussed. It has been known for a long time that being themselves mostly harmless species, superoxide and NO are precursors of really reactive species hydroxyl radicals and peroxynitrite, the initiators of aging and various pathologies. However, contemporary studies demonstrate the other maybe more important ways of damaging activity of physiological free radicals. Numerous studies show that lessening of NO production and its bioavailability could be a starting point of aging development. It results in a decrease in NO inhibition of mitochondrial cytochrome c oxidase and an increase in dioxygen consumption. That in its turn leads to an increase in the production of superoxide and the other reactive oxygen and nitrogen species and initiation of apoptosis, In conclusion the possibilities of pharmacological intervention with antioxidants and other antiradical procedures to suppress aging and senescence or even to expand the life span of animals are considered.
Topics: Aging; Antioxidants; Catalysis; Free Radicals; Humans; Nitric Oxide; Prostaglandin-Endoperoxide Synthases; Superoxides
PubMed: 19273321
DOI: 10.2741/3499 -
Chemical Reviews Mar 2016Superoxide ion (O2(•-)) is of great significance as a radical species implicated in diverse chemical and biological systems. However, the chemistry knowledge of... (Review)
Review
Superoxide ion (O2(•-)) is of great significance as a radical species implicated in diverse chemical and biological systems. However, the chemistry knowledge of O2(•-) is rather scarce. In addition, numerous studies on O2(•-) were conducted within the latter half of the 20th century. Therefore, the current advancement in technology and instrumentation will certainly provide better insights into mechanisms and products of O2(•-) reactions and thus will result in new findings. This review emphasizes the state-of-the-art research on O2(•-) so as to enable researchers to venture into future research. It comprises the main characteristics of O2(•-) followed by generation methods. The reaction types of O2(•-) are reviewed, and its potential applications including the destruction of hazardous chemicals, synthesis of organic compounds, and many other applications are highlighted. The O2(•-) environmental chemistry is also discussed. The detection methods of O2(•-) are categorized and elaborated. Special attention is given to the feasibility of using ionic liquids as media for O2(•-), addressing the latest progress of generation and applications. The effect of electrodes on the O2(•-) electrochemical generation is reviewed. Finally, some remarks and future perspectives are concluded.
Topics: Chemistry Techniques, Synthetic; Electrodes; Environmental Restoration and Remediation; Hazardous Substances; Ionic Liquids; Refuse Disposal; Superoxides
PubMed: 26875845
DOI: 10.1021/acs.chemrev.5b00407 -
Magnetic Resonance in Medicine Aug 2021QuEnch-assiSTed (QUEST) MRI provides a unique biomarker of excessive production of paramagnetic free radicals (oxidative stress) in vivo. The contribution from...
PURPOSE
QuEnch-assiSTed (QUEST) MRI provides a unique biomarker of excessive production of paramagnetic free radicals (oxidative stress) in vivo. The contribution from superoxide, a common upstream species found in oxidative stress-based disease, to the QUEST metric is unclear. Here, we begin to address this question by measuring superoxide spin-lattice relaxivity (r1) in phantoms.
METHODS
Stable superoxide free radicals were generated in water phantoms of potassium superoxide ( . To measure r1, 1/T of different concentration solutions of KO in the presence and absence of the antioxidant superoxide dismutase were measured. The 1/T confounding factors including acquisition sequence, pH, and water source were also evaluated.
RESULTS
The T -weighted signal intensity increased with KO concentration. No contribution from pH, or reaction products other than superoxide, noted on 1/T . Superoxide r1 was measured to be 0.29 mM s , in agreement with that reported for paramagnetic molecular oxygen and nitroxide free radicals.
CONCLUSION
Our first-in-kind measurement of superoxide free radical r1 suggests a detection sensitivity of QUEST MRI on the order of tens of μM, within the reported level of free radical production during oxidative stress in vivo. Similar studies for other common free radicals are needed.
Topics: Electron Spin Resonance Spectroscopy; Free Radicals; Magnetic Resonance Imaging; Oxidative Stress; Phantoms, Imaging; Superoxides
PubMed: 33755248
DOI: 10.1002/mrm.28722 -
The Journal of Biological Chemistry Sep 2013Peroxynitrite is the product of the diffusion-controlled reaction of nitric oxide and superoxide radicals. Peroxynitrite, a reactive short-lived peroxide with a pKa of... (Review)
Review
Peroxynitrite is the product of the diffusion-controlled reaction of nitric oxide and superoxide radicals. Peroxynitrite, a reactive short-lived peroxide with a pKa of 6.8, is a good oxidant and nucleophile. It also yields secondary free radical intermediates such as nitrogen dioxide and carbonate radicals. Much of nitric oxide- and superoxide-dependent cytotoxicity resides on peroxynitrite, which affects mitochondrial function and triggers cell death via oxidation and nitration reactions. Peroxynitrite is an endogenous toxicant but is also a cytotoxic effector against invading pathogens. The biological chemistry of peroxynitrite is modulated by endogenous antioxidant mechanisms and neutralized by synthetic compounds with peroxynitrite-scavenging capacity.
Topics: Animals; Humans; Hydrogen-Ion Concentration; Mitochondria; Nitric Oxide; Nitrogen; Oxidants; Oxidation-Reduction; Peroxynitrous Acid; Superoxide Dismutase; Superoxides; Tyrosine
PubMed: 23861390
DOI: 10.1074/jbc.R113.472936 -
Free Radical Biology & Medicine Oct 2009(6R)-5,6,7,8-Tetrahydrobiopterin (BH(4)) is an endogenously produced pterin that is found widely distributed in mammalian tissues. BH(4) works as a cofactor of aromatic... (Review)
Review
(6R)-5,6,7,8-Tetrahydrobiopterin (BH(4)) is an endogenously produced pterin that is found widely distributed in mammalian tissues. BH(4) works as a cofactor of aromatic amino acid hydroxylases and nitric oxide synthases. In the vasculature a deficit of BH(4) is implicated in the mechanisms of several diseases including atherosclerosis, hypertension, diabetic vascular disease, and vascular complications from cigarette smoking and environmental pollution. These ill-effects are connected to the ability of BH(4) to regulate reactive oxygen species levels in the endothelium. The possibility of using BH(4) as a therapeutical agent in cardiovascular medicine is becoming more compelling and many biochemical and physiological aspects involved in this application are currently under investigation. This review summarizes our current understanding of BH(4) reactivity and some aspects of cellular production and regulation.
Topics: Biopterins; Cardiovascular Diseases; Humans; Superoxides; Vasodilation
PubMed: 19628033
DOI: 10.1016/j.freeradbiomed.2009.07.024 -
Anti-cancer Agents in Medicinal... May 2011Superoxide dismutases (SOD) are considered to be antioxidant enzymes. This view came about because its substrate, superoxide, is a free radical; in the era of their... (Review)
Review
Superoxide dismutases (SOD) are considered to be antioxidant enzymes. This view came about because its substrate, superoxide, is a free radical; in the era of their discovery, 1960's - 1970's, the general mindset was that free radicals in biology must be damaging. Indeed SOD blunts the cascade of oxidations initiated by superoxide. However in the late 1970's it was observed that cancer cells that have low activity of the mitochondrial form of SOD, MnSOD, grow faster than those with higher activities of MnSOD. These observations indicated that SOD, superoxide, and hydrogen peroxide affected the basic biology of cells and tissues, not just via damaging oxidation reactions. It is now realized that superoxide and hydrogen peroxide are essential for normal cellular and organism function. MnSOD appears to be a central player in the redox biology of cells and tissues.
Topics: Antioxidants; Free Radicals; Humans; Hydrogen Peroxide; Mitochondria; Oxidation-Reduction; Superoxide Dismutase; Superoxides
PubMed: 21453242
DOI: 10.2174/187152011795677544 -
Journal of Physiology and Pharmacology... Dec 2003Nitric oxide (NO) and reactive oxygen species exert multiple modulating effects on inflammation and play a key role in the regulation of immune responses. They affect... (Review)
Review
Nitric oxide (NO) and reactive oxygen species exert multiple modulating effects on inflammation and play a key role in the regulation of immune responses. They affect virtually every step of the development of inflammation. Low concentrations of nitric oxide produced by constitutive and neuronal nitric oxide synthases inhibit adhesion molecule expression, cytokine and chemokine synthesis and leukocyte adhesion and transmigration. Large amounts of NO, generated primarily by iNOS can be toxic and pro-inflammatory. Actions of nitric oxide are however not dependent primarily on the enzymatic source, but rather on the cellular context, NO concentration (dependent on the distance from NO source) and initial priming of immune cells. These observations may explain difficulties in determining the exact role of NO in Th1 and Th2 lymphocyte balance in normal immune responses and in allergic disease. Similarly superoxide anion produced by NAD(P)H oxidases present in all cell types participating in inflammation (leukocytes, endothelial and other vascular cells etc) may lead to toxic effects, when produced at high levels during oxidative burst, but may also modulate inflammation in a far more discrete way, when continuously produced at low levels by NOXs (non-phagocytic oxidases). The effects of both nitric oxide and superoxide in immune regulation are exerted through multiple mechanisms, which include interaction with cell signalling systems like cGMP, cAMP, G-protein, JAK/STAT or MAPK dependent signal transduction pathways. They may also lead to modification of transcription factors activity and in this way modulate the expression of multiple other mediators of inflammation. Moreover genetic polymorphisms exist within genes encoding enzymes producing both NO and superoxide. The potential role of these polymorphisms in inflammation and susceptibility to infection is discussed. Along with studies showing increasing role of NO and free radicals in mediating inflammatory responses drugs which interfere with these systems are being introduced in the treatment of inflammation. These include statins, angiotensin receptor blockers, NAD(P)H oxidase inhibitors, NO-aspirin and others. In conclusion in this mini-review we discuss the mechanisms of nitric oxide and superoxide dependent modulation of inflammatory reactions in experimental animals and humans. We also discuss potential roles of nitric oxide as a mediator of allergic inflammation.
Topics: Animals; Humans; Inflammation; Inflammation Mediators; Models, Biological; Nitric Oxide; Signal Transduction; Superoxides
PubMed: 14726604
DOI: No ID Found