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Theriogenology Jul 2022Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the mediators of redox activity and are known to perform concentration-specific bimodal roles. At... (Review)
Review
Reactive oxygen species (ROS) and reactive nitrogen species (RNS) are the mediators of redox activity and are known to perform concentration-specific bimodal roles. At lower concentrations, serves as a molecular messenger and signaling molecule while at higher concentrations induces stress which in turn alters the sperm's functional characteristics. Production of ROS and RNS cannot be prevented entirely and should not be followed as a pragmatic approach as they are involved in numerous sperm physiological functions. When the antioxidants defense armory is meager, excess generation of these species cross the physiological limits and inactivates essential metabolic enzymes and disrupts signal transduction altering normal sperm functions. As per the available literature, oxidants mostly arise as a result of pathological conditions or cryopreservation-induced injury. Dead and debilitated or abnormal spermatozoa and associated leukocytes release free radicals in an excess amount which elicits oxidative and nitrosative stressors that are potentially toxic to cryosurviving sperm. ROS plays a double edge sword effect on sperm function, as regulators of physiological mechanisms at low levels and as toxicants when produced at high concentrations. Recently nitric oxide (NO) has emerged as a potential regulator of sperm physiology, in addition, found to mediate homeostasis of the seminal plasma microenvironment when semen samples are incubated with optimal concentrations of NO compounds. The NO compounds can provide some resistance to future stresses which are not usually harnessed by using the defensive strategy of supplementing antioxidants. Therefore, through the optimized addition of NO donor and inhibitor in extender, the free radical-induced damage can be avoided without inhibiting their essential physiological effects on fertilization and subsequent embryo development. This article is intended to describe the role of reactive oxidants in the physiology and pathophysiology of spermatozoa and their relationship with various seminal attributes.
Topics: Animals; Antioxidants; Cattle; Male; Nitric Oxide; Nitrogen; Oxidants; Oxygen; Reactive Oxygen Species; Sperm Motility; Spermatozoa
PubMed: 35512515
DOI: 10.1016/j.theriogenology.2022.04.024 -
The Journal of Physiology Jun 2021LRRC8A-containing anion channels associate with NADPH oxidase 1 (Nox1) and regulate superoxide production and tumour necrosis factor-α (TNFα) signalling. Here we show...
KEY POINTS
LRRC8A-containing anion channels associate with NADPH oxidase 1 (Nox1) and regulate superoxide production and tumour necrosis factor-α (TNFα) signalling. Here we show that LRRC8C and 8D also co-immunoprecipitate with Nox1 in vascular smooth muscle cells. LRRC8C knockdown inhibited TNFα-induced O production, receptor endocytosis, nuclear factor-κB (NF-κB) activation and proliferation while LRRC8D knockdown enhanced NF-κB activation. Significant changes in LRRC8 isoform expression in human atherosclerosis and psoriasis suggest compensation for increased inflammation. The oxidant chloramine-T (ChlorT, 1 mM) weakly (∼25%) inhibited LRRC8C currents but potently (∼80%) inhibited LRRC8D currents. Substitution of the extracellular loop (EL1, EL2) domains of 8D into 8C conferred significantly stronger (69%) ChlorT-dependent inhibition. ChlorT exposure impaired subsequent current block by DCPIB, which occurs through interaction with EL1, further implicating external oxidation sites. LRRC8A/C channels most effectively sustain Nox1 activity at the plasma membrane. This may result from their ability to remain active in an oxidized microenvironment.
ABSTRACT
Tumour necrosis factor-α (TNFα) activates NADPH oxidase 1 (Nox1) in vascular smooth muscle cells (VSMCs), producing superoxide (O ) required for subsequent signalling. LRRC8 family proteins A-E comprise volume-regulated anion channels (VRACs). The required subunit LRRC8A physically associates with Nox1, and VRAC activity is required for Nox activity and the inflammatory response to TNFα. VRAC currents are modulated by oxidants, suggesting that channel oxidant sensitivity and proximity to Nox1 may play a physiologically relevant role. In VSMCs, LRRC8C knockdown (siRNA) recapitulated the effects of siLRRC8A, inhibiting TNFα-induced extracellular and endosomal O production, receptor endocytosis, nuclear factor-κB (NF-κB) activation and proliferation. In contrast, siLRRC8D potentiated NF-κB activation. Nox1 co-immunoprecipitated with 8C and 8D, and colocalized with 8D at the plasma membrane and in vesicles. We compared VRAC currents mediated by homomeric and heteromeric LRRC8C and LRRC8D channels expressed in HEK293 cells. The oxidant chloramine T (ChlorT, 1 mM) weakly inhibited 8C, but potently inhibited 8D currents. ChlorT exposure also impaired subsequent current block by the VRAC blocker DCPIB, implicating external sites of oxidation. Substitution of the 8D extracellular loop domains (EL1, EL2) into 8C conferred significantly stronger ChlorT-mediated inhibition of 8C currents. Our results suggest that LRRC8A/C channel activity can be effectively maintained in the oxidized microenvironment expected to result from Nox1 activation at the plasma membrane. Increased ratios of 8D:8C expression may potentially depress inflammatory responses to TNFα. LRRC8A/C channel downregulation represents a novel strategy to reduce TNFα-induced inflammation.
Topics: Anions; HEK293 Cells; Humans; Membrane Proteins; NADPH Oxidase 1; Oxidants; Superoxides
PubMed: 33932953
DOI: 10.1113/JP281577 -
Journal of Inorganic Biochemistry May 2021Oxidation of the anti-tumour agent [Pt{(p-BrCF)NCHCHNEt}Cl(py)], 1 (py = pyridine) with hydrogen peroxide under a variety of conditions yields a range of...
Oxidation of the anti-tumour agent [Pt{(p-BrCF)NCHCHNEt}Cl(py)], 1 (py = pyridine) with hydrogen peroxide under a variety of conditions yields a range of organoenamineamidoplatinum(II) compounds [Pt{(p-BrCF)NCH=C(X)NEt}Cl(py)] (X = H, Cl, Br) as well as species with shared occupancy involving H, Cl and Br. Thus, oxidation of the -CH-CH- backbone (dehydrogenation) occurs, often accompanied by substitution. Oxidation of 1 with HO in acetone yielded 1:1 co-crystallized [Pt{(p-BrCF)NCH=CHNEt}Cl(py)], 1H and [Pt{(p-BrCF)NCH=C(Cl)NEt}Cl(py)], 1Cl. The former was obtained pure in low yield from the oxidation of 1 with (NH)[Ce(NO)] in acetone, and the latter was obtained from 1 and HO in CHCl at near reflux. From the latter reaction under vigorous refluxing [Pt{(p-BrCF)NCH=C(Br)NEt}Cl(py)], 1Br was isolated. In refluxing acetonitrile, oxidation of 1 with HO yielded [Pt{(p-BrCF)NCH=C(H.Br)NEt}Cl(py)], 1HBr, in which the alkene is mainly substituted by Br in a dual occupancy. Treatment of 1 with HO and tetrabutylammonium hydroxide in acetone at room temperature formed [Pt{(p-HCF)NCHCHNEt}Cl(py)], 2. Oxidation of [Pt{(p-HCF)NCHCHNEt}Br(py)], 3 with HO in boiling acetonitrile gave the ligand oxidation product [Pt{(p-HCF)NCH=C(Br)NEt}Br(py)], 3Br. All major products were identified by X-ray crystallography as well as by H and F NMR spectra. In cases of mixed crystals or dual occupancy compounds, the F and H NMR spectra showed dissociation into the components in the solution in the same proportions as in isolated crystalline material.
Topics: Antineoplastic Agents; Crystallography, X-Ray; Hydrogen Peroxide; Models, Molecular; Molecular Structure; Organoplatinum Compounds; Oxidants; Oxidation-Reduction
PubMed: 33711633
DOI: 10.1016/j.jinorgbio.2021.111360 -
Journal of Esthetic and Restorative... Mar 2022This study evaluated the influence of over-the-counter agents on the maintenance of color and microhardness of the enamel after home bleaching protocol.
OBJECTIVE
This study evaluated the influence of over-the-counter agents on the maintenance of color and microhardness of the enamel after home bleaching protocol.
MATERIALS AND METHODS
Specimens of bovine teeth (6 × 6 × 2 mm) were prepared, and color (Easyshade, VITA) and microhardness (HMV-2, Shimadzu) readings were performed. All the specimens were bleached using 22% carbamide peroxide (22%CP), except for the control group, and then separated into seven groups (n = 10) according to the interaction of toothpaste (whitening, conventional, and whitening with peroxide) and mouth rinse (whitening and conventional). The study simulated 1 year of toothbrushing (Pepsodent, MAVTEC) and mouth rinse by immersion. After that, final color and microhardness measurements were performed. Data were analyzed by one-way ANOVA, Tukey's test (P < .05).
RESULTS
The group submitted to 22%CP + whitening toothpaste + whitening mouth rinse showed higher color maintenance (P < .05) than the control group. The perception of whitening of teeth (ΔWI ) was higher than the color change (ΔE ). There was a decrease in microhardness after treatment with 22%CP + conventional toothpaste + whitening mouth rinse.
CONCLUSIONS
Over-the-counter products can help with the maintenance of tooth whitening after bleaching with carbamide peroxide; however, special attention should be given since the association of products can also reduce the microhardness of the dental enamel.
CLINICAL SIGNIFICANCE
The association between whitening toothpastes and mouth rinses might be beneficial for maintaining color during 1 year after bleaching treatment.
Topics: Animals; Bleaching Agents; Carbamide Peroxide; Cattle; Color; Dental Enamel; Hydrogen Peroxide; Tooth Bleaching; Tooth Bleaching Agents
PubMed: 32627389
DOI: 10.1111/jerd.12617 -
Food Chemistry Dec 2022To compare the differences between direct protein oxidation (PO) and lipid-derived PO, the myofibrillar protein (MP) of obscure pufferfish was oxidatively modified by...
To compare the differences between direct protein oxidation (PO) and lipid-derived PO, the myofibrillar protein (MP) of obscure pufferfish was oxidatively modified by the hydroxyl radical oxidizing system (HOS) and the lipid-oxidizing system (LOS). The degree of oxidation, structural characteristics, and oxidation sites in MP were assessed. The results showed there was no significant thiol loss in LOS, compared with a 77.64% loss observed in case of the HOS. The secondary structure of MP was more vulnerable to HOS, but the tertiary structure was more susceptible to LOS. The cross-linking was largely attributed to the reversible disulfide links in HOS and the irreversible covalent linkages in LOS. Six amino acids and 10 specific oxidant products were identified in HOS. Only three amino acids and three specific oxidant products were identified in LOS. These findings may help deepen the understanding regarding the mechanism underlying PO in protein- and lipid-rich food materials.
Topics: Amino Acids; Hydroxyl Radical; Lipids; Myofibrils; Oxidants; Oxidation-Reduction
PubMed: 35872498
DOI: 10.1016/j.foodchem.2022.133710 -
Astrobiology Dec 2016In 1976, the Viking landers carried out the most comprehensive search for organics and microbial life in the martian regolith. Their results indicate that Mars' surface... (Review)
Review
In 1976, the Viking landers carried out the most comprehensive search for organics and microbial life in the martian regolith. Their results indicate that Mars' surface is lifeless and, surprisingly, depleted in organics at part-per-billion levels. Several biology experiments on the Viking landers gave controversial results that have since been explained by the presence of oxidizing agents on the surface of Mars. These oxidants may degrade abiotic or biological organics, resulting in their nondetection in the regolith. As several exploration missions currently focus on the detection of organics on Mars (or will do so in the near future), knowledge of the oxidative state of the surface is fundamental. It will allow for determination of the capability of organics to survive on a geological timescale, the most favorable places to seek them, and the best methods to process the samples collected at the surface. With this aim, we review the main oxidants assumed to be present on Mars, their possible formation pathways, and those laboratory studies in which their reactivity with organics under Mars-like conditions has been evaluated. Among the oxidants assumed to be present on Mars, only four have been detected so far: perchlorate ions (ClO) in salts, hydrogen peroxide (HO) in the atmosphere, and clays and metal oxides composing surface minerals. Clays have been suggested as catalysts for the oxidation of organics but are treated as oxidants in the following to keep the structure of this article straightforward. This work provides an insight into the oxidizing potential of the surface of Mars and an estimate of the stability of organic matter in an oxidizing environment. Key Words: Mars surface-Astrobiology-Oxidant-Chemical reactions. Astrobiology 16, 977-996.
Topics: Extraterrestrial Environment; Mars; Oxidants; Oxidation-Reduction; Soil; Space Flight
PubMed: 27925795
DOI: 10.1089/ast.2016.1502 -
Free Radical Research Jun 2015Selenium is an essential trace element in mammals, with the majority specifically encoded as seleno-L-cysteine into a range of selenoproteins. Many of these proteins... (Review)
Review
Selenium is an essential trace element in mammals, with the majority specifically encoded as seleno-L-cysteine into a range of selenoproteins. Many of these proteins play a key role in modulating oxidative stress, via either direct detoxification of biological oxidants, or repair of oxidised residues. Both selenium- and sulphur-containing residues react readily with the wide range of oxidants (including hydrogen peroxide, radicals, singlet oxygen and hypochlorous, hypobromous, hypothiocyanous and peroxynitrous acids) that are produced during inflammation and have been implicated in the development of a range of inflammatory diseases. Whilst selenium has similar properties to sulphur, it typically exhibits greater reactivity with most oxidants, and there are considerable differences in the subsequent reactivity and ease of repair of the oxidised species that are formed. This review discusses the chemistry of low-molecular-mass organoselenium compounds (e.g. selenoethers, diselenides and selenols) with inflammatory oxidants, with a particular focus on the reaction kinetics and product studies, with the differences in reactivity between selenium and sulphur analogues described in the selected examples. These data provide insight into the therapeutic potential of low-molecular-mass selenium-containing compounds to modulate the activity of both radical and molecular oxidants and provide protection against inflammation-induced damage. Progress in their therapeutic development (including modulation of potential selenium toxicity by strategic design) is demonstrated by a brief summary of some recent studies where novel organoselenium compounds have been used as wound healing or radioprotection agents and in the prevention of cardiovascular disease.
Topics: Animals; Humans; Inflammation; Kinetics; Organoselenium Compounds; Oxidants; Oxidative Stress
PubMed: 25854915
DOI: 10.3109/10715762.2015.1018247 -
Water Research Nov 2022Studies that promote chemical oxidation by permanganate (MnO; Mn(VII)) as a viable technology for water treatment and environmental purification have been quickly... (Review)
Review
Studies that promote chemical oxidation by permanganate (MnO; Mn(VII)) as a viable technology for water treatment and environmental purification have been quickly accumulating over the past decades. Various methods to activate Mn(VII) have been proposed and their efficacy in destructing a wide range of emerging organic contaminants has been demonstrated. This article aims to present a state-of-art review on the development of Mn(VII) activation methods, including photoactivation, electrical activation, the addition of redox mediators, carbonaceous materials, and other chemical agents, with a particular focus on the potential activation mechanism and critical influencing factors. Different reaction mechanisms are involved in activated Mn(VII) oxidation processes, including the generation of reactive intermediates derived from Mn(VII) (e.g., Mn(III), Mn(V), and Mn(VI)) or activators (e.g., intermediates of redox mediators and Ru catalysts), reactive oxygen species (ROS) (e.g., •OH, O, and O), as well as electron transfer from organics to Mn(VII) via catalysts as the electron mediator. Except •OH that is generated as one of co-oxidants in UV/Mn(VII) process, other reactive species are relatively mild oxidants, which are more selective toward organic substrates and highly tolerant toward various water matrices (e.g., inorganic ions and natural organic matter) compared to strongly oxidizing radical species. Therefore, activated Mn(VII) oxidation processes show a good prospect for efficient removal of target contaminants in natural and complex environmental matrices. However, there are some disputes about the dominant reactive species generated in these processes, and their identification methods may be not appropriate, causing serious confusion in the mechanistic understanding. So, further efforts are still needed to fill the knowledge gap and also to address the application challenges of these technologies.
Topics: Manganese Compounds; Oxides; Oxidation-Reduction; Water Purification; Oxidants; Catalysis
PubMed: 36279614
DOI: 10.1016/j.watres.2022.119265 -
Chemosphere Mar 2021Catalytic activation of different oxidants including peroxymonosulfate (PMS), peroxydisulfate (PDS), hydrogen peroxide (HO) and ozone (O) by MnO for degradation of...
Catalytic activation of different oxidants including peroxymonosulfate (PMS), peroxydisulfate (PDS), hydrogen peroxide (HO) and ozone (O) by MnO for degradation of sulfachloropyridazine (SCP) was investigated and the effects of different crystalline phases of MnO including nanowire α-MnO, nanorod β-MnO, nanofiber γ-MnO, and nanosphere δ-MnO on catalytic ozonation of SCP were also studied. The SCP degradation and total organic carbon removal indicated that the oxidation efficiency of the peroxide oxidants followed an order of O/MnO > PMS/MnO > PDS/MnO > HO/MnO. In catalytic ozonation, SCP degradation rate constants of different MnO phases followed an order of δ-MnO > α-MnO > γ-MnO> β-MnO. Electron paramagnetic resonance (EPR) suggested that hydroxyl radicals (·OH) and singlet oxygen (O) might be more significant for SCP degradation than sulfate (SO) and superoxide (·O) radicals. Radical competition experiments demonstrated that O and ·OH contributed to 63.16% and 28.07%, respectively, for the catalytic ozonation of SCP. It was also found that more oxygen vacancies, specific surface area and exposure of MnO edges could facilitate the activation of O for O and ·OH productions and SCP degradation. The degradation pathways of SCP could mainly follow the cleavage of S-C or S-N bond and dechlorination, accompanied by hydroxylation and oxidation.
Topics: Hydrogen Peroxide; Manganese Compounds; Oxidants; Oxidation-Reduction; Oxides; Ozone; Peroxides; Sulfachlorpyridazine; Water Pollutants, Chemical
PubMed: 33348268
DOI: 10.1016/j.chemosphere.2020.129287 -
Chemical Research in Toxicology Aug 2023Myeloperoxidase (MPO) is an important component of the human innate immune system and the main source of a strong oxidizing and chlorinating species, hypochlorous acid...
Myeloperoxidase (MPO) is an important component of the human innate immune system and the main source of a strong oxidizing and chlorinating species, hypochlorous acid (HOCl). Inadvertent, misplaced, or excessive generation of HOCl by MPO is associated with multiple human inflammatory diseases. Therefore, there is a considerable interest in the development of MPO inhibitors. Here, we report the synthesis and characterization of a boronobenzyl derivative of acetaminophen (AMBB), which can function as a proinhibitor of MPO and release acetaminophen, the inhibitor of chlorination cycle of MPO, in the presence of inflammatory oxidants, i.e., hydrogen peroxide, hypochlorous acid, or peroxynitrite. We demonstrate that the AMBB proinhibitor undergoes conversion to acetaminophen by all three oxidants, with the involvement of the primary phenolic product intermediate, with relatively long half-life at pH 7.4. The determined rate constants of the reaction of the AMBB proinhibitor with hydrogen peroxide, hypochlorous acid, or peroxynitrite are equal to 1.67, 1.6 × 10, and 1.0 × 10 M s, respectively. AMBB showed lower MPO inhibitory activity (IC > 0.3 mM) than acetaminophen (IC = 0.14 mM) toward MPO-dependent HOCl generation. Finally, based on the determined reaction kinetics and the observed inhibitory effects of two plasma components, uric acid and albumin, on the extent of AMBB oxidation by ONOO and HOCl, we conclude that ONOO is the most likely potential activator of AMBB in human plasma.
Topics: Humans; Oxidants; Acetaminophen; Hypochlorous Acid; Hydrogen Peroxide; Peroxidase; Peroxynitrous Acid; Oxidation-Reduction
PubMed: 37534491
DOI: 10.1021/acs.chemrestox.3c00140