Superoxide-mediated decomposition of biological S-nitrosothiols.

PubMed

Aleryani, S; Milo, E; Rose, Y; Kostka, P

1998-03-13

Incubation of S-nitrosocysteine or S-nitrosoglutathione (5-100 M) in the presence of a generator of superoxide (xanthine/xanthine oxidase) resulted in a time-dependent decomposition of S-nitrosothiols and accumulation of nitrite/nitrate in reaction mixtures. Quantitatively, the amounts of nitrite/nitrate represented >90% of nitrosonium equivalent of S-nitrosothiols degraded during the incubation. The reaction rates were unaffected by the presence catalase (1 unit/ml). Kinetic analysis showed that the degradation of S-nitrosothiols in the presence of superoxide proceeded at second order rate constants of 76,900 M-1 s-1 (S-nitrosocysteine) and 12,800 M-1 s-1 (S-nitrosoglutathione), respectively, with a stoichiometric ratio of 1 mol of S-nitrosothiol per 2 mol of superoxide. The findings provide the evidence for the involvement of superoxide in the metabolism of S-nitrosothiols. Furthermore, substantially slower reaction rates of superoxide with S-nitrosothiols relative to the reaction rate with NO are consistent with the contention that the transient formation of S-nitrosothiols in biological systems may protect NO from its rapid destruction by superoxide, thus enabling these compounds to serve as carriers or buffers of NO.

Extremophilic Enzymatic Response for Protection against UV-Radiation Damage

DTIC Science & Technology

2012-09-17

superoxide dismutase from the thermophile E1 is a very active enzyme and extremely efficient in its function as antioxidant by capturing superoxide radicals...Ollivet-Besson, Papić, L., Blamey J.M. “Optimization of the antioxidant activity of the enzyme superoxide dismutase from the thermophile E1 induced by...antioxidant enzymes , superoxide dismutase and catalase, from selected microorganisms and the contribution of these enzymes to the resistance to extreme and

A flow-system comparison of the reactivities of calcium superoxide and potassium superoxide with carbon dioxide and water vapor

NASA Technical Reports Server (NTRS)

Wood, P. C.; Ballou, E. V.; Spitze, L. A.; Wydeven, T.

1982-01-01

A single pass flow system was used to test the reactivity of calcium superoxide with respiratory gases and the performance was compared to that of potassium superoxide. The KO2 system is used by coal miners as a self-contained unit in rescue operations. Particular attention was given to the reactivity with carbon dioxide and water vapor at different temperatures and partial pressures of oxygen, carbon dioxide, and water vapor. The calcium superoxide beds were found to absorb CO2 and H2O vapor, releasing O2. The KO2 bed, however, released O2 at twice the rate of CO2 absorption at 37 C. It is concluded that the calcium superoxide material is not a suitable replacement for the KO2 bed, although Ca(O2)2 may be added to the KO2 bed to enhance the CO2 absorption.

Kinetic investigation of catalytic disproportionation of superoxide ions in the non-aqueous electrolyte used in Li–air batteries

DOE PAGES

Wang, Qiang; Zheng, Dong; McKinnon, Meaghan E.; ...

2014-10-28

Superoxide reacts with carbonate solvents in Li–air batteries. Tris(pentafluorophenyl)borane is found to catalyze a more rapid superoxide (O 2 -) disproportionation reaction than the reaction between superoxide and propylene carbonate (PC). With this catalysis, the negative impact of the reaction between the electrolyte and O 2 -produced by the O 2 reduction can be minimized. A simple kinetic study using ESR spectroscopy was reported to determine reaction orders and rate constants for the reaction between PC and superoxide, and the disproportionation of superoxide catalyzed by Tris(pentafluorophenyl)borane and Li ions. As a result, the reactions are found to be first ordermore » and the rate constants are 0.033 s -1 M -1, 0.020 s -1 M -1and 0.67 s -1M -1 for reactions with PC, Li ion and Tris(pentafluorophenyl)borane, respectively.« less

Inhibitory effects of cardols and related compounds on superoxide anion generation by xanthine oxidase.

PubMed

Masuoka, Noriyoshi; Nihei, Ken-ichi; Maeta, Ayami; Yamagiwa, Yoshiro; Kubo, Isao

2015-01-01

5-Pentadecatrienylresorcinol, isolated from cashew nuts and commonly known as cardol (C₁₅:₃), prevented the generation of superoxide radicals catalysed by xanthine oxidase without the inhibition of uric acid formation. The inhibition kinetics did not follow the Michelis-Menten equation, but instead followed the Hill equation. Cardol (C₁₀:₀) also inhibited superoxide anion generation, but resorcinol and cardol (C₅:₀) did not inhibit superoxide anion generation. The related compounds 3,5-dihydroxyphenyl alkanoates and alkyl 2,4-dihydroxybenzoates, had more than a C9 chain, cooperatively inhibited but alkyl 3,5-dihydroxybenzoates, regardless of their alkyl chain length, did not inhibit the superoxide anion generation. These results suggested that specific inhibitors for superoxide anion generation catalysed by xanthine oxidase consisted of an electron-rich resorcinol group and an alkyl chain having longer than C9 chain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Superoxide anion production by human neutrophils activated by Trichomonas vaginalis.

PubMed

Song, Hyun-Ouk; Ryu, Jae-Sook

2013-08-01

Neutrophils are the predominant inflammatory cells found in vaginal discharges of patients infected with Trichomonas vaginalis. In this study, we examined superoxide anion (O2 (.-)) production by neutrophils activated by T. vaginalis. Human neutrophils produced superoxide anions when stimulated with either a lysate of T. vaginalis, its membrane component (MC), or excretory-secretory product (ESP). To assess the role of trichomonad protease in production of superoxide anions by neutrophils, T. vaginalis lysate, ESP, and MC were each pretreated with a protease inhibitor cocktail before incubation with neutrophils. Superoxide anion production was significantly decreased by this treatment. Trichomonad growth was inhibited by preincubation with supernatants of neutrophils incubated for 3 hr with T. vaginalis lysate. Furthermore, myeloperoxidase (MPO) production by neutrophils was stimulated by live trichomonads. These results indicate that the production of superoxide anions and MPO by neutrophils stimulated with T. vaginalis may be a part of defense mechanisms of neutrophils in trichomoniasis.

Zymographic Method for Distinguishing Different Classes of Superoxide Dismutases in Plants.

PubMed

Jamdhade, Ashwini R; Sunkar, Ramanjulu; Hivrale, Vandana K

2017-01-01

In plants, especially in chloroplasts, superoxide radical is generated when an electron is transferred to dimolecular O 2 due to decreased activity of Photosystem I. The superoxide (O 2 - ) radical accumulation is more rampant in plants exposed to abiotic stresses due to oxidation of photosystem components. Excessive superoxide radical accumulation will lead to oxidative damage to the cellular macromolecules. The ubiquitous superoxide dismutases (SODs) represent critical enzymatic antioxidant system present in cells, which can catalyze the disproportion of superoxide (O 2 - ) radical rapidly into hydrogen peroxide (H 2 O 2 ) and molecular oxygen. Depending on the metal cofactor present, the plant SODs are classified into Cu/ZnSOD, MnSOD, and FeSOD. The activity of SODs can be quantified zymographically. Additionally, using this method, different classes of SODs can be distinguished by using H 2 O 2 , KCN, and NaN 3.

Cryo-Trapping the Distorted Octahedral Reaction Intermediate of Manganese Superoxide Dismutase

NASA Technical Reports Server (NTRS)

Borgstahl, Gloria; Snell, Edward H.; Rose, M. Franklin (Technical Monitor)

2000-01-01

Superoxide dismutase protects organisms from potentially damaging oxygen radicals by catalyzing the disproportion of superoxide to oxygen and hydrogen peroxide. We report the use of cryogenic temperatures to kinetically trap the 6th ligand bound to the active site of manganese superoxide dismutase. Using cryocrystallography and synchrotron radiation, we describe at 1.55A resolution the six-coordinate, distorted octahedral geometry assumed by the active site during catalysis and compare it to the room temperature, five-coordinate trigonal-bipyramidal active site. Gateway residues Tyr34, His30 and a tightly bound water molecule are implicated in closing off the active site and blocking the escape route of superoxide during dismutation.

Inhibitory effect of nicergoline on superoxide generation by activated rat microglias measured using a simple chemiluminescence method.

PubMed

Yoshida, T; Tanaka, M; Okamoto, K

2001-01-05

We evaluated the effect of nicergoline on superoxide production by rat microglias using a 2-methyl-6-(p-methoxyphenyl)-3, 7-dihydroimidazo[1,2-a]pyrazin-3-one-dependent chemiluminescence assay. Nicergoline dose-dependently inhibited superoxide production by microglias stimulated with phorbol myristate acetate or opsonized zymosan, while it had no effect on superoxide production by a hypoxanthine-xanthine oxidase system. These results indicate that nicergoline does not have a scavenging effect, but has an inhibitory effect on superoxide generation by microglias. Although this drug is commonly used for treating chronic cerebral infarction, it may also have a protective effect on progression of Parkinson's disease or Alzheimer's disease.

Indirect detection of superoxide in RAW 264.7 macrophage cells using microchip electrophoresis coupled to laser-induced fluorescence.

PubMed

de Campos, Richard P S; Siegel, Joseph M; Fresta, Claudia G; Caruso, Giuseppe; da Silva, José A F; Lunte, Susan M

2015-09-01

Superoxide, a naturally produced reactive oxygen species (ROS) in the human body, is involved in many pathological and physiological signaling processes. However, if superoxide formation is left unregulated, overproduction can lead to oxidative damage to important biomolecules, such as DNA, lipids, and proteins. Superoxide can also lead to the formation of peroxynitrite, an extremely hazardous substance, through its reaction with endogenously produced nitric oxide. Despite its importance, quantitative information regarding superoxide production is difficult to obtain due to its high reactivity and low concentrations in vivo. MitoHE, a fluorescent probe that specifically reacts with superoxide, was used in conjunction with microchip electrophoresis (ME) and laser-induced fluorescence (LIF) detection to investigate changes in superoxide production by RAW 264.7 macrophage cells following stimulation with phorbol 12-myristate 13-acetate (PMA). Stimulation was performed in the presence and absence of the superoxide dismutase (SOD) inhibitors, diethyldithiocarbamate (DDC) and 2-metoxyestradiol (2-ME). The addition of these inhibitors resulted in an increase in the amount of superoxide specific product (2-OH-MitoE(+)) from 0.08 ± 0.01 fmol (0.17 ± 0.03 mM) in native cells to 1.26 ± 0.06 fmol (2.5 ± 0.1 mM) after PMA treatment. This corresponds to an approximately 15-fold increase in intracellular concentration per cell. Furthermore, the addition of 3-morpholino-sydnonimine (SIN-1) to the cells during incubation resulted in the production of 0.061 ± 0.006 fmol (0.12 ± 0.01 mM) of 2-OH-MitoE(+) per cell on average. These results demonstrate that indirect superoxide detection coupled with the use of SOD inhibitors and a separation method is a viable method to discriminate the 2-OH-MitoE(+) signal from possible interferences.

Design and reactivity of Ni-complexes using pentadentate neutral-polypyridyl ligands: Possible mimics of NiSOD.

PubMed

Snider, Victoria G; Farquhar, Erik R; Allen, Mark; Abu-Spetani, Ayah; Mukherjee, Anusree

2017-10-01

Superoxide plays a key role in cell signaling, but can be cytotoxic within cells unless well regulated by enzymes known as superoxide dismutases (SOD). Nickel superoxide dismutase (NiSOD) catalyzes the disproportion of the harmful superoxide radical into hydrogen peroxide and dioxygen. NiSOD has a unique active site structure that plays an important role in tuning the potential of the nickel center to function as an effective catalyst for superoxide dismutation with diffusion controlled rates. The synthesis of structural and functional analogues of NiSOD provides a route to better understand the role of the nickel active site in superoxide dismutation. In this work, the synthesis of a series of nickel complexes supported by nitrogen rich pentadentate ligands is reported. The complexes have been characterized through absorption spectroscopy, mass spectrometry, and elemental analysis. X-ray absorption spectroscopy was employed to establish the oxidation state and the coordination geometry around the metal center. The reactivity of these complexes toward KO 2 was evaluated to elucidate the role of the coordination sphere in controlling superoxide dismutation reactivity. Copyright © 2017 Elsevier Inc. All rights reserved.

Biological Superoxide In Manganese Oxide Formation

NASA Astrophysics Data System (ADS)

Hansel, C.; Learman, D.; Zeiner, C.; Santelli, C. M.

2011-12-01

Manganese (Mn) oxides are among the strongest sorbents and oxidants within the environment, controlling the fate and transport of numerous elements and the degradation of recalcitrant carbon. Both bacteria and fungi mediate the oxidation of Mn(II) to Mn(III/IV) oxides but the genetic and biochemical mechanisms responsible remain poorly understood. Furthermore, the physiological basis for microbial Mn(II) oxidation remains an enigma. We have recently reported that a common marine bacterium (Roseobacter sp. AzwK-3b) oxidizes Mn(II) via reaction with extracellular superoxide (O2-) produced during exponential growth. Here we expand this superoxide-mediated Mn(II) oxidation pathway to fungi, introducing a surprising homology between prokaryotic and eukaryotic metal redox processes. For instance, Stibella aciculosa, a common soil Ascomycete filamentous fungus, precipitates Mn oxides at the base of asexual reproductive structures (synnemata) used to support conidia (Figure 1). This distribution is a consequence of localized production of superoxide (and it's dismutation product hydrogen peroxide, H2O2), leading to abiotic oxidation of Mn(II) by superoxide. Disruption of NADPH oxidase activity using the oxidoreductase inhibitor DPI leads to diminished cell differentiation and subsequent Mn(II) oxidation inhibition. Addition of Cu(II) (an effective superoxide scavenger) leads to a concentration dependent decrease in Mn oxide formation. We predict that due to the widespread production of extracellular superoxide within the fungal and likely bacterial kingdoms, biological superoxide may be an important contributor to the cycling of Mn, as well as other metals (e.g., Hg, Fe). Current and future explorations of the genes and proteins involved in superoxide production and Mn(II) oxidation will ideally lend insight into the physiological and biochemical basis for these processes.

Hydroxynonenal and uncoupling proteins: a model for protection against oxidative damage.

PubMed

Echtay, Karim S; Pakay, Julian L; Esteves, Telma C; Brand, Martin D

2005-01-01

In this mini review we summarize recent studies from our laboratory that show the involvement of superoxide and the lipid peroxidation product 4-hydroxynonenal in the regulation of mitochondrial uncoupling. Superoxide produced during mitochondrial respiration is a major cause of the cellular oxidative damage that may underlie degenerative diseases and ageing. Superoxide production is very sensitive to the magnitude of the mitochondrial protonmotive force, so can be strongly decreased by mild uncoupling. Superoxide is able to give rise to other reactive oxygen species, which elicit deleterious effects primarily by oxidizing intracellular components, including lipids, DNA and proteins. Superoxide-induced lipid peroxidation leads to the production of reactive aldehydes, including 4-hydroxynonenal. These aldehydic lipid peroxidation products are in turn able to modify proteins such as mitochondrial uncoupling proteins and the adenine nucleotide translocase, converting them into active proton transporters. This activation induces mild uncoupling and so diminishes mitochondrial superoxide production, hence protecting against disease and oxidative damage at the expense of energy production.

Catalytic superoxide scavenging by metal complexes of the calcium chelator EGTA and contrast agent EHPG.

PubMed

Fisher, Anna E O; Hague, Theresa A; Clarke, Charlotte L; Naughton, Declan P

2004-10-08

Metal ion chelators widely used in experimental protocols and clinical diagnosis are generally assumed to be inert. We previously reported that the ubiquitous chelator EDTA has high levels of superoxide suppressing activity. Here, we report that the common chelators calcium chelator EGTA and contrast agent EHPG have significant activities in suppressing superoxide levels depending on the nature of metal ion chelated. The most active species is Mn(II)-EGTA which exhibited an IC50 value of 0.19 microM for superoxide destruction. In addition, IC50 values for Mn(II)-EHPG and 2Cu(II)-EGTA were 0.69 and 0.60 microM, respectively. In conclusion, Mn(II) and Cu(II) complexes of the common chelators EGTA and EHPG exhibit considerable superoxide scavenging activities. Caution should be employed in their use in biological systems where superoxide has a key role and they may be useful for the development of catalytic anti-oxidants. Copyright 2004 Elsevier Inc.

Protective activity of hamamelitannin on cell damage induced by superoxide anion radicals in murine dermal fibroblasts.

PubMed

Masaki, H; Atsumi, T; Sakurai, H

1995-01-01

Previously we demonstrated that hamamelitannin (2',5-di-O-galloyl hamamelose) in Hamamelis virginiana L. exhibits potent superoxide-anion scavenging activity. We then examined the physiological and pharmacological activities of hamamelitannin as well as its functional homologues, gallic acid and syringic acid. The following results were obtained: (1) Hamamelitannin has a higher protective activity against cell damages induced by superoxide anions than gallic acid which is the functional moiety of hamamelitannin. The protective activity of hamamelitannin on murine fibroblast-damage induced by superoxide anions was found at a minimum concentration of 50 microM, while the corresponding figure for gallic acid was 100 microM. (2) Pre-treatment of fibroblasts with hamamelitannin enhances cell survival. (3) The superoxide-anion scavenging activity of the compound in terms of its IC50 value (50% inhibition concentration of superoxide anion radicals generated) was evaluated by ESR spin-trapping. Both hamamelitannin (IC50 = 1.31 +/- 0.06 microM) and gallic acid (IC50 = 1.01 +/- 0.03 microM) exhibited high superoxide-anion scavenging activity followed by syringic acid (IC50 = 13.90 +/- 2.38 microM). (4) When hamamelitannin was treated with superoxide anions generated by a KO2-crown ether system, HPLC analysis showed the disappearance of hamamelitannin and the concomitant formation of hamamelitannin-derived radicals (g = 2.005, delta H1 = 2.16 G, delta H2 = 4.69 G) was detected by ESR spectrometry.(ABSTRACT TRUNCATED AT 250 WORDS)

ROLE OF COPPER,ZINC-SUPEROXIDE DISMUTASE IN CATALYZING NITROTYROSINE FORMATION IN MURINE LIVER

USDA-ARS?s Scientific Manuscript database

The solely known function of Cu,Zn-superoxide dismutase (SOD1) is to catalyze the dismutation of superoxide anion into hydrogen peroxide. Our objective was to determine if SOD1 catalyzed murine liver protein nitration induced by acetaminophen (APAP) and lipopolysaccharide (LPS). Liver and plasma ...

Superoxide Dismutase Protects Cells from DNA Damage Induced by Trivalent Methylated Arsenicals

EPA Science Inventory

Superoxide dismutase (SOD) catalyzes the conversion of superoxide to hydrogen peroxide. Heterozygous mice of strain B6; 129S7-Sod1(tm1Leb)/J were obtained from Jackson Laboratories and bred to produce offspring that were heterozygous (+/Sod1(tm1Leb)), homozygous wild-type (+/+), ...

Method for digesting a nitro-bearing explosive compound

DOEpatents

Shah, Manish M.

2000-01-01

The present invention is a process wherein superoxide radicals from superoxide salt are used to break down the explosive compounds. The process has an excellent reaction rate for degrading explosives, and operates at ambient temperature and atmospheric pressure in aqueous or non-aqueous conditions. Because the superoxide molecules are small, much smaller than an enzyme molecule for example, they can penetrate the microstructure of plastic explosives faster. The superoxide salt generates reactive hydroxyl radicals, which can destroy other organic contaminants, if necessary, along with digesting the explosive nitro-bearing compound.

Rapid generation of mitochondrial superoxide induces mitochondrion-dependent but caspase-independent cell death in hippocampal neuronal cells that morphologically resembles necroptosis☆

PubMed Central

Fukui, Masayuki; Choi, Hye Joung; Zhu, Bao Ting

2013-01-01

Studies in recent years have revealed that excess mitochondrial superoxide production is an important etiological factor in neurodegenerative diseases, resulting from oxidative modifications of cellular lipids, proteins, and nucleic acids. Hence, it is important to understand the mechanism by which mitochondrial oxidative stress causes neuronal death. In this study, the immortalized mouse hippocampal neuronal cells (HT22) in culture were used as a model and they were exposed to menadione (also known as vitamin K3) to increase intracellular superoxide production. We found that menadione causes preferential accumulation of superoxide in the mitochondria of these cells, along with the rapid development of mitochondrial dysfunction and cellular ATP depletion. Neuronal death induced by menadione is independent of the activation of the MAPK signaling pathways and caspases. The lack of caspase activation is due to the rapid depletion of cellular ATP. It was observed that two ATP-independent mitochondrial nucleases, namely, AIF and Endo G, are released following menadione exposure. Silencing of their expression using specific siRNAs results in transient suppression (for ~12 h) of mitochondrial superoxide-induced neuronal death. While suppression of the mitochondrial superoxide dismutase expression markedly sensitizes neuronal cells to mitochondrial superoxide-induced cytotoxicity, its over-expression confers strong protection. Collectively, these findings showed that many of the observed features associated with mitochondrial superoxide-induced cell death, including caspase independency, rapid depletion of ATP level, mitochondrial release of AIF and Endo G, and mitochondrial swelling, are distinctly different from those of apoptosis; instead they resemble some of the known features of necroptosis. PMID:22575170

Simultaneous evaluation of superoxide content and mitochondrial membrane potential in stallion semen samples provides additional information about sperm quality.

PubMed

Johannisson, A; Figueiredo, M I; Al-Kass, Z; Morrell, J M

2018-05-01

An improved fertility prediction for stallions is of importance for equine breeding. Here, we investigate the potential of a combined staining of stallion spermatozoa for superoxide and mitochondrial membrane potential (MMP) for this purpose. Semen samples were analysed immediately after arrival at the laboratory, as well as after 24 h. Superoxide was measured by MitoSOXRed, while MMP was measured with JC-1. Menadione was used to stimulate superoxide production. In addition, other parameters of sperm quality, namely motility, membrane integrity, chromatin integrity, sperm kinematics and Hoechst 33258 exclusion were measured and correlated to superoxide production and MMP. Both bivariate correlations between measured parameters as well as multivariate analysis were performed. Measured values in the superoxide/MMP assay did not correlate with other parameters. However, there was a strong negative correlation (r = 0.96 after 0 h, r = 0.95 after 24 h) between membrane integrity and chromatin integrity. Moderate positive correlations were found between motility parameters and membrane integrity, as well as moderate negative correlations between motility parameters and chromatin integrity. The multivariate analysis revealed that membrane integrity, chromatin integrity and motility contributed to the first principal component, while the second was influenced by superoxide/MMP parameters as well as sperm kinematics. Storage of samples for 24 h decreased motility, chromatin integrity and membrane integrity. In conclusion, combined measurement of superoxide and MMP provides additional information not obtained by other assays of sperm quality. Copyright © 2018 Elsevier B.V. All rights reserved.

Do Superoxide Dismutase (SOD) and Catalase (CAT) protect Cells from DNA Damage Induced by Active Arsenicals?

EPA Science Inventory

Superoxide dismutase (SOD) catalyzes the conversion of superoxide to hydrogen peroxide, which can be converted to water and oxygen through the action of catalase. Heterozygous mice of strain B6: 129S7-SodltmlLeb/J were obtained from Jackson Laboratories and bred to produce offspr...

Formation and Detoxification of Reactive Oxygen Species

ERIC Educational Resources Information Center

Kuciel, Radoslawa; Mazurkiewicz, Aleksandra

2004-01-01

A model of reactive oxygen species metabolism is proposed as a laboratory exercise for students. The superoxide ion in this model is generated during the reaction of oxidation of xanthine, catalyzed by xanthine oxidase. The effect of catalase, superoxide dismutase, and allopurinol on superoxide ion generation and removal in this system is also…

[Cell surface peroxidase--generator of superoxide anion in wheat root cells under wound stress].

PubMed

Chasov, A V; Gordon, L Kh; Kolesnikov, O P; Minibaeva, F V

2002-01-01

Development of wound stress in excised wheat roots is known to be accompanied with an increase in reactive oxygen species (ROS) production, fall of membrane potential, release of K+ from cells, alkalization of extracellular solution, changes in respiration and metabolism of structural lipids. Dynamics of superoxide release correlates with changes in other physiological parameters, indicating the cross-reaction of these processes. Activity of peroxidase in extracellular solution after a 1 h incubation and removal of roots was shown to be stimulated by the range of organic acids, detergents, metals, and to be inhibited by cyanide. Superoxide production was sensitive to the addition of Mn2+ and H2O2. Increase in superoxide production correlates with the enhancement of peroxidase activity at the application of organic acids and detergents. The results obtained indicate that cell surface peroxidase is one of the main generators of superoxide in wounded wheat root cells. Different ways of stimulation of the ROS producing activity in root cells is supposed. By controlling superoxide and hydrogen peroxide formation, the cell surface peroxidase can control the adaptation processes in stressed plant cells.

Neuron-specific regulation of superoxide dismutase amid pathogen-induced gut dysbiosis.

PubMed

Horspool, Alexander M; Chang, Howard C

2018-05-19

Superoxide dismutase, an enzyme that converts superoxide into less-toxic hydrogen peroxide and oxygen, has been shown to mediate behavioral response to pathogens. However, it remains largely unknown how superoxide dismutase is regulated in the nervous system amid pathogen-induced gut dysbiosis. Although there are five superoxide dismutases in C. elegans, our genetic analyses suggest that SOD-1 is the primary superoxide dismutase to mediate the pathogen avoidance response. When C. elegans are fed a P. aeruginosa diet, the lack of SOD-1 contributes to enhanced lethality. We found that guanylyl cyclases GCY-5 and GCY-22 and neuropeptide receptor NPR-1 act antagonistically to regulate SOD-1 expression in the gustatory neuron ASER. After C. elegans ingests a diet that contributes to high levels of oxidative stress, the temporal regulation of SOD-1 and the SOD-1-dependent response in the gustatory system demonstrates a sophisticated mechanism to fine-tune behavioral plasticity. Our results may provide the initial glimpse of a strategy by which a multicellular organism copes with oxidative stress amid gut dysbiosis. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Ab initio molecular dynamics of the reaction of quercetin with superoxide radical

NASA Astrophysics Data System (ADS)

Lespade, Laure

2016-08-01

Superoxide plays an important role in biology but in unregulated concentrations it is implicated in a lot of diseases such as cancer or atherosclerosis. Antioxidants like flavonoids are abundant in plant and are good scavengers of superoxide radical. The modeling of superoxide scavenging by flavonoids from the diet still remains a challenge. In this study, ab initio molecular dynamics of the reaction of the flavonoid quercetin toward superoxide radical has been carried out using Car-Parrinello density functional theory. The study has proven different reactant solvation by modifying the number of water molecules surrounding superoxide. The reaction consists in the gift of a hydrogen atom of one of the hydroxyl groups of quercetin to the radical. When it occurs, it is relatively fast, lower than 100 fs. Calculations show that it depends largely on the environment of the hydroxyl group giving its hydrogen atom, the geometry of the first water layer and the presence of a certain number of water molecules in the second layer, indicating a great influence of the solvent on the reactivity.

Enzymatic defenses against the toxicity of oxygen and of streptonigrin in Escherichia coli.

PubMed

Hassan, H M; Fridovich, I

1977-03-01

Anaerobically grown Escherichia coli K-12 contain only one superoxide dismutase and that is the iron-containing isozyme found in the periplasmic space. Exposure to oxygen caused the induction of a manganese-containing superoxide dismutase and of another, previously undescribed, superoxide dismutase, as well as of catalase and peroxidase. These inductions differed in their responsiveness towards oxygen. Thus the very low levels of oxygen present in deep, static, aerobic cultures were enough for nearly maximal induction of the manganese-superoxide dismutase. In contrast, induction of the new superoxide dismutase, catalase, and peroxidase required the much higher levels of oxygen achieved in vigorously agitated aerobic cultures. Anaerobically grown cells showed a much greater oxygen enhancement of the lethality of streptonigrin than did aerobically grown cells, in accord with the proposal that streptonigrin can serve as an intracellular source of superoxide. Anaerobically grown cells in which enzyme inductions were prevented by puromycin were damaged by exposure to air. This damage was evidenced both as a decline in viable cell count and as structural abnormalities evident under an electron microscope.

Rebamipide attenuates nonsteroidal anti-inflammatory drugs (NSAID) induced lipid peroxidation by the manganese superoxide dismutase (MnSOD) overexpression in gastrointestinal epithelial cells.

PubMed

Nagano, Y; Matsui, H; Shimokawa, O; Hirayama, A; Tamura, M; Nakamura, Y; Kaneko, T; Rai, K; Indo, H P; Majima, H J; Hyodo, I

2012-04-01

Nonsteroidal anti-inflammatory drugs (NSAIDs) often cause gastrointestinal complications such as gastric ulcers and erosions. Recent studies on the pathogenesis have revealed that NSAIDs induce lipid peroxidation in gastric epithelial cells by generating superoxide anion in mitochondria, independently with cyclooxygenase-inhibition and the subsequent prostaglandin deficiency. Although not clearly elucidated, the impairment of mitochondrial oxidative phosphorylation, or uncoupling, by NSAIDs is associated with the generation of superoxide anion. Physiologically, superoxide is immediately transformed into hydrogen peroxide and diatomic oxygen with manganese superoxide dismutase (MnSOD). Rebamipide is an antiulcer agent that showed protective effects against NSAID-induced lipid peroxidation in gastrointestinal tracts. We hypothesized that rebamipide may attenuate lipid peroxidation by increasing the expression of MnSOD protein in mitochondria and decreasing the leakage of superoxide anion in NSAID-treated gastric and small intestinal epithelial cells. Firstly, to examine rebamipide increases the expression of MnSOD proteins in mitochondria of gastrointestinal epithelial cells, we underwent Western blotting analysis against anti-MnSOD antibody in gastric RGM1 cells and small intestinal IEC6 cells. Secondly, to examine whether the pretreatment of rebamipide decreases NSAID-induced mitochondrial impairment and lipid peroxidation, we treated these cells with NSAIDs with or without rebamipide pretreatment, and examined with specific fluorescent indicators. Finally, to examine whether pretreatment of rebamipide attenuates NSAID-induced superoxide anion leakage from mitochondria, we examined the mitochondria from indomethacin-treated RGM1 cells with electron spin resonance (ESR) spectroscopy using a specific spin-trapping reagent, CYPMPO. Rebamipide increased the expression of MnSOD protein, and attenuated NSAID-induced mitochondrial impairment and lipid peroxidation in RGM1 and IEC6 cells. The pretreatment of rebamipide significantly decreased the signal intensity of superoxide anion from the mitochondria. We conclude that rebamipide attenuates lipid peroxidation by increasing the expression of MnSOD protein and decreasing superoxide anion leakage from mitochondria in both gastric and small intestinal epithelial cells.

Rapid generation of mitochondrial superoxide induces mitochondrion-dependent but caspase-independent cell death in hippocampal neuronal cells that morphologically resembles necroptosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fukui, Masayuki; Choi, Hye Joung; Zhu, Bao Ting, E-mail: BTZhu@kumc.edu

Studies in recent years have revealed that excess mitochondrial superoxide production is an important etiological factor in neurodegenerative diseases, resulting from oxidative modifications of cellular lipids, proteins, and nucleic acids. Hence, it is important to understand the mechanism by which mitochondrial oxidative stress causes neuronal death. In this study, the immortalized mouse hippocampal neuronal cells (HT22) in culture were used as a model and they were exposed to menadione (also known as vitamin K{sub 3}) to increase intracellular superoxide production. We found that menadione causes preferential accumulation of superoxide in the mitochondria of these cells, along with the rapid developmentmore » of mitochondrial dysfunction and cellular ATP depletion. Neuronal death induced by menadione is independent of the activation of the MAPK signaling pathways and caspases. The lack of caspase activation is due to the rapid depletion of cellular ATP. It was observed that two ATP-independent mitochondrial nucleases, namely, AIF and Endo G, are released following menadione exposure. Silencing of their expression using specific siRNAs results in transient suppression (for ∼ 12 h) of mitochondrial superoxide-induced neuronal death. While suppression of the mitochondrial superoxide dismutase expression markedly sensitizes neuronal cells to mitochondrial superoxide-induced cytotoxicity, its over-expression confers strong protection. Collectively, these findings showed that many of the observed features associated with mitochondrial superoxide-induced cell death, including caspase independency, rapid depletion of ATP level, mitochondrial release of AIF and Endo G, and mitochondrial swelling, are distinctly different from those of apoptosis; instead they resemble some of the known features of necroptosis. -- Highlights: ► Menadione causes mitochondrial superoxide accumulation and injury. ► Menadione-induced cell death is caspase-independent, due to rapid depletion of ATP. ► The release of AIF and Endo G contributes importantly to cell death. ► Alterations of SOD1 or SOD2 levels alter menadione-induced neuronal cytotoxicity.« less

[Cu,Zn]-Superoxide Dismutase Mutants of the Swine Pathogen Actinobacillus pleuropneumoniae Are Unattenuated in Infections of the Natural Host

PubMed Central

Sheehan, Brian J.; Langford, Paul R.; Rycroft, Andrew N.; Kroll, J. Simon

2000-01-01

Actinobacillus pleuropneumoniae, the causative agent of porcine pleuropneumonia, contains a periplasmic Cu- and Zn-cofactored superoxide dismutase ([Cu,Zn]-SOD, or SodC) which has the potential, realized in other pathogens, to promote bacterial survival during infection by dismutating host-defense-derived superoxide. Here we describe the construction of a site-specific, [Cu,Zn]-SOD-deficient A. pleuropneumoniae serotype 1 mutant and show that although the mutant is highly sensitive to the microbicidal action of superoxide in vitro, it remains fully virulent in experimental pulmonary infection in pigs. PMID:10899887

The French Paradox: Determining the Superoxide-Scavenging Capacity of Red Wine and Other Beverages

ERIC Educational Resources Information Center

Logan, Barry A.; Hammond, Matthew P.; Stormo, Benjamin M.

2008-01-01

Plant-derived phenolic compounds such as those found in red wine, tea, and certain fruit juices may protect against cardiovascular disease by detoxifying (scavenging) superoxide and other unstable reactive oxygen species. We present a laboratory exercise that can be used to assess the superoxide-scavenging capacity of beverages. Among the…

The 2-Oxoacid Dehydrogenase Complexes in Mitochondria Can Produce Superoxide/Hydrogen Peroxide at Much Higher Rates Than Complex I*

PubMed Central

Quinlan, Casey L.; Goncalves, Renata L. S.; Hey-Mogensen, Martin; Yadava, Nagendra; Bunik, Victoria I.; Brand, Martin D.

2014-01-01

Several flavin-dependent enzymes of the mitochondrial matrix utilize NAD+ or NADH at about the same operating redox potential as the NADH/NAD+ pool and comprise the NADH/NAD+ isopotential enzyme group. Complex I (specifically the flavin, site IF) is often regarded as the major source of matrix superoxide/H2O2 production at this redox potential. However, the 2-oxoglutarate dehydrogenase (OGDH), branched-chain 2-oxoacid dehydrogenase (BCKDH), and pyruvate dehydrogenase (PDH) complexes are also capable of considerable superoxide/H2O2 production. To differentiate the superoxide/H2O2-producing capacities of these different mitochondrial sites in situ, we compared the observed rates of H2O2 production over a range of different NAD(P)H reduction levels in isolated skeletal muscle mitochondria under conditions that favored superoxide/H2O2 production from complex I, the OGDH complex, the BCKDH complex, or the PDH complex. The rates from all four complexes increased at higher NAD(P)H/NAD(P)+ ratios, although the 2-oxoacid dehydrogenase complexes produced superoxide/H2O2 at high rates only when oxidizing their specific 2-oxoacid substrates and not in the reverse reaction from NADH. At optimal conditions for each system, superoxide/H2O2 was produced by the OGDH complex at about twice the rate from the PDH complex, four times the rate from the BCKDH complex, and eight times the rate from site IF of complex I. Depending on the substrates present, the dominant sites of superoxide/H2O2 production at the level of NADH may be the OGDH and PDH complexes, but these activities may often be misattributed to complex I. PMID:24515115

Direct Evidence of Solution-Mediated Superoxide Transport and Organic Radical Formation in Sodium-Oxygen Batteries.

PubMed

Xia, Chun; Fernandes, Russel; Cho, Franklin H; Sudhakar, Niranjan; Buonacorsi, Brandon; Walker, Sean; Xu, Meng; Baugh, Jonathan; Nazar, Linda F

2016-09-07

Advanced large-scale electrochemical energy storage requires cost-effective battery systems with high energy densities. Aprotic sodium-oxygen (Na-O2) batteries offer advantages, being comprised of low-cost elements and possessing much lower charge overpotential and higher reversibility compared to their lithium-oxygen battery cousins. Although such differences have been explained by solution-mediated superoxide transport, the underlying nature of this mechanism is not fully understood. Water has been suggested to solubilize superoxide via formation of hydroperoxyl (HO2), but direct evidence of these HO2 radical species in cells has proven elusive. Here, we use ESR spectroscopy at 210 K to identify and quantify soluble HO2 radicals in the electrolyte-cold-trapped in situ to prolong their lifetime-in a Na-O2 cell. These investigations are coupled to parallel SEM studies that image crystalline sodium superoxide (NaO2) on the carbon cathode. The superoxide radicals were spin-trapped via reaction with 5,5-dimethyl-pyrroline N-oxide at different electrochemical stages, allowing monitoring of their production and consumption during cycling. Our results conclusively demonstrate that transport of superoxide from cathode to electrolyte leads to the nucleation and growth of NaO2, which follows classical mechanisms based on the variation of superoxide content in the electrolyte and its correlation with the crystallization of cubic NaO2. The changes in superoxide content upon charge show that charge proceeds through the reverse solution process. Furthermore, we identify the carbon-centered/oxygen-centered alkyl radicals arising from attack of these solubilized HO2 species on the diglyme solvent. This is the first direct evidence of such species, which are likely responsible for electrolyte degradation.

Magnetic Resonance Imaging of Mitochondrial Dysfunction and Metabolic Activity, Accompanied by Overproduction of Superoxide.

PubMed

Bakalova, Rumiana; Georgieva, Ekaterina; Ivanova, Donika; Zhelev, Zhivko; Aoki, Ichio; Saga, Tsuneo

2015-12-16

This study shows that a mitochondria-penetrating nitroxide probe (mito-TEMPO) allows detection of superoxide and visualization of mitochondrial dysfunction in living cells due to the effect of T1 shortening in MRI. Mitochondrial dysfunction was induced by treatment of cells with rotenone and 2-methoxyestradiol (2-ME/Rot). The MRI measurements were performed on 7T MRI. The 2-ME/Rot-treated cells were characterized by overproduction of superoxide, which was confirmed by a conventional dihydroethidium test. In the presence of mito-TEMPO, the intensity of MRI signal in 2-ME/Rot-treated cells was ∼30-40% higher, in comparison with that in untreated cells or culture media. In model (cell-free) systems, we observed that superoxide, but not hydrogen peroxide, increased the intensity of T1-weighted MRI signal of mito-TEMPO. Moreover, the superoxide restores the T1-weighted MRI contrast of mito-TEMPOH, a noncontrast (diamagnetic) analogue of mito-TEMPO. This was also confirmed by using EPR spectroscopy. The results demonstrate that superoxide radical is involved in the enhancement of T1-weighted MRI contrast in living cells, in the absence and presence of mito-TEMPO. This report gives a direction for discovering new opportunities for functional MRI, for detection of metabolic activity, accompanied by overproduction of superoxide, as well as by disturbance of the balance between superoxide and hydrogen peroxide, a very important approach to clarify the fine molecular mechanisms in the regulation of many pathologies. The visualization of mitochondrial activity in real-time can be crucial to clarify the molecular mechanism of the functional MRI in its commonly accepted definition, as a method for detection of neurovascular coupling.

In vitro susceptibility of Mycobacterium leprae to oxygen-mediated damage.

PubMed

Dhople, A M

1996-01-01

In order to evaluate factors responsible for the failure of Mycobacterium leprae to multiply in cell-free cultures in vitro studies were undertaken to determine the possible poisoning of the organism by hydroxide and superoxide radicals produced in the growth medium. The superoxide dismutase activity was very low, 10% of the levels found in armadillo cells, while measured activity of catalase and glutathione peroxidase was negligible. Susceptibility of M. leprae to hydrogen peroxide was enhanced by potassium iodide but not by lactoperoxidase. The addition of high amounts of catalase completely prevented hydrogen peroxide-mediated killing of M. leprae. Superoxide generated by the action of xanthine oxidase on xanthine was lethal to M. leprae, but superoxide dismutase added to the reaction mixture gave significant protection. Thus superoxide radicals may be a major cause for the sudden termination of growth of M. leprae in primary cultures and also for failure of subcultures.

Superoxide dismutase and catalase protect cultured hepatocytes from the cytotoxicity of acetaminophen.

PubMed

Kyle, M E; Miccadei, S; Nakae, D; Farber, J L

1987-12-31

Superoxide dismutase, catalase and mannitol prevent the killing of cultured hepatocytes by acetaminophen in the presence of an inhibitor of glutathione reductase, BCNU. Under these conditions, the cytotoxicity of acetaminophen depends upon its metabolism, since beta-naphthoflavone, an inhibitor of mixed function oxidation, prevents the cell killing. In hepatocytes made resistant to acetaminophen by pretreatment with the ferric iron chelator, deferoxamine, addition of ferric or ferrous iron restores the sensitivity to acetaminophen. In such a situation, both superoxide dismutase and catalase prevent the killing by acetaminophen in the presence of ferric iron. By contrast, catalase, but not superoxide dismutase, prevents the cell killing dependent upon addition of ferrous iron. These results document the participation of both superoxide anion and hydrogen peroxide in the killing of cultured hepatocytes by acetaminophen and suggest that hydroxyl radicals generated by an iron catalyzed Haber-Weiss reaction mediate the cell injury.

Superoxide activates a GDP-sensitive proton conductance in skeletal muscle mitochondria from king penguin (Aptenodytes patagonicus).

PubMed

Talbot, Darren A; Hanuise, Nicolas; Rey, Benjamin; Rouanet, Jean-Louis; Duchamp, Claude; Brand, Martin D

2003-12-26

We present the partial nucleotide sequence of the avian uncoupling protein (avUCP) gene from king penguin (Aptenodytes patagonicus), showing that the protein is 88-92% identical to chicken (Gallus gallus), turkey (Meleagris gallopavo), and hummingbird (Eupetomena macroura). We show that superoxide activates the proton conductance of mitochondria isolated from king penguin skeletal muscle. GDP abolishes the superoxide-activated proton conductance, indicating that it is mediated via avUCP. In the absence of superoxide there is no GDP-sensitive component of the proton conductance from penguin muscle mitochondria demonstrating that avUCP plays no role in the basal proton leak.

The sites and topology of mitochondrial superoxide production

PubMed Central

Brand, Martin D.

2010-01-01

Mitochondrial superoxide production is an important source of reactive oxygen species in cells, and may cause or contribute to ageing and the diseases of ageing. Seven major sites of superoxide production in mammalian mitochondria are known and widely accepted. In descending order of maximum capacity they are the ubiquinone binding sites in complex I (site IQ) and complex III (site IIIQo), glycerol 3-phosphate dehydrogenase, the flavin in complex I (site IF), the electron transferring flavoprotein:Q oxidoreductase (ETFQOR) of fatty acid beta oxidation, and pyruvate and 2-oxoglutarate dehydrogenases. None of these sites is fully characterized and for some we only have sketchy information. The topology of the sites is important because it determines whether or not a site will produce superoxide in the mitochondrial matrix and be able to damage mitochondrial DNA. All sites produce superoxide in the matrix; site IIIQo and glycerol 3-phosphate dehydrogenase also produce superoxide to the intermembrane space. The relative contribution of each site to mitochondrial reactive oxygen species generation in the absence of electron transport inhibitors is unknown in isolated mitochondria, in cells or in vivo, and may vary considerably with species, tissue, substrate, energy demand and oxygen tension. PMID:20064600

Effect of UV radiation on a thermostable superoxide dismutase purified from a thermophilic bacterium isolated from a sterilization drying oven.

PubMed

Monsalves, María T; Amenábar, Maximiliano J; Ollivet-Besson, Gabriela P; Blamey, Jenny M

2013-07-01

A thermostable superoxide dismutase from a thermophilic bacterium, called Geobacillus wiegeli (GWE1), isolated from the interior of a sterilization drying oven, was purified by anion-exchange and molecular size-exclusion liquid chromatography. On the basis of SDS-PAGE, the purified enzyme was found to be homogeneous and showed an estimated subunit molecular mass of 23.9 kDa. The holoenzyme is a homotetramer of 97.3 kDa. Superoxide dismutase exhibited maximal activity at pH 8.5 and at temperature around 60 ºC. The enzyme was thermostable maintaining 50% of its activity even after 4.5 hours incubation at 60 ºC and more than 70% of its activity after 30 min at 80 ºC. When the microorganism was irradiated with UVA, an increase in the specific activity of superoxide dismutase was observed which was correlated with decreasing levels of anion superoxide, indicating the direct involvement of this enzyme in the capture of reactive oxygen species. This study reports the effects of UV radiation on a superoxide dismutase from a thermophilic bacterium isolated from an anthropogenic environment.

Competitive Deprotonation and Superoxide [O₂⁻•)] Radical-Anion Adduct Formation Reactions of Carboxamides under Negative-Ion Atmospheric-Pressure Helium-Plasma Ionization (HePI) Conditions.

PubMed

Hassan, Isra; Pinto, Spencer; Weisbecker, Carl; Attygalle, Athula B

2016-03-01

Carboxamides bearing an N-H functionality are known to undergo deprotonation under negative-ion-generating mass spectrometric conditions. Herein, we report that N-H bearing carboxamides with acidities lower than that of the hydroperoxyl radical (HO-O(•)) preferentially form superoxide radical-anion (O2(-•)) adducts, rather than deprotonate, when they are exposed to the glow discharge of a helium-plasma ionization source. For example, the spectra of N-alkylacetamides show peaks for superoxide radical-anion (O2(-•)) adducts. Conversely, more acidic amides, such as N-alkyltrifluoroacetamides, preferentially undergo deprotonation under similar experimental conditions. Upon collisional activation, the O2(-•) adducts of N-alkylacetamides either lose the neutral amide or the hydroperoxyl radical (HO-O(•)) to generate the superoxide radical-anion (m/z 32) or the deprotonated amide [m/z (M - H)(-)], respectively. For somewhat acidic carboxamides, the association between the two entities is weak. Thus, upon mildest collisional activation, the adduct dissociates to eject the superoxide anion. Superoxide-adduct formation results are useful for structure determination purposes because carboxamides devoid of a N-H functionality undergo neither deprotonation nor adduct formation under HePI conditions.

Fenoterol inhibits superoxide anion generation by human polymorphonuclear leukocytes via beta-adrenoceptor-dependent and -independent mechanisms.

PubMed

Mirza, Zafar Nazir; Kato, Masahiko; Kimura, Hirokazu; Tachibana, Atsushi; Fujiu, Toru; Suzuki, Masato; Mochizuki, Hiroyuki; Tokuyama, Kenichi; Morikawa, Akihiro

2002-05-01

Beta2-adrenoceptor agonists, used widely as bronchodilator in treating bronchial asthma, may have anti-inflammatory activity. We examined whether various widely prescribed beta2-adrenoceptor agonists differ in anti-inflammatory mechanisms. We investigated effects of these drugs on superoxide anion generation by stimulated human polymorphonuclear leukocytes in vitro using chemiluminescence. At high concentrations, fenoterol significantly inhibited both N-formylmethionyl-leucyl-phenylalanine- and phorbol myristate acetate-induced superoxide generation by neutrophils. In contrast, salbutamol or procaterol partially inhibited generation with the former stimulus but not the latter. Inhibition by salbutamol or procaterol was completely reversed by either propranolol, a nonselective beta-adrenoceptor antagonist, or ICI-118551, a beta2-adrenoceptor-selective antagonist. In contrast, the effect of fenoterol at concentrations exceeding 10(-6) M against superoxide generation with the former stimulus was only partially reversed by antagonists, and the effect of high concentrations of fenoterol against generation with the latter stimulus was not reversed. No drugs scavenged superoxide at the highest concentration used (10(-5) M). Fenoterol at high concentrations has an inhibitory effect on superoxide generation that includes a component not mediated via beta2-adrenoceptors. Direct inhibition at or downstream from protein kinase C may be involved.

Effect of uric acid on inflammatory COX-2 and ROS pathways in vascular smooth muscle cells.

PubMed

Oğuz, Nurgül; Kırça, Mustafa; Çetin, Arzu; Yeşilkaya, Akın

2017-10-01

Hyperuricemia is thought to play a role in cardiovascular diseases (CVD), including hypertension, coronary artery disease and atherosclerosis. However, exactly how uric acid contributes to these pathologies is unknown. An underlying mechanism of inflammatory diseases, such as atherosclerosis, includes enhanced production of cyclooxygenase-2 (COX-2) and superoxide anion. Here, we aimed to examine the effect of uric acid on inflammatory COX-2 and superoxide anion production and to determine the role of losartan. Primarily cultured vascular smooth muscle cells (VSMCs) were time and dose-dependently induced by uric acid and COX-2 and superoxide anion levels were measured. COX-2 levels were determined by ELISA, and superoxide anion was measured by the superoxide dismutase (SOD)-inhibitable reduction of ferricytochrome c method. Uric acid elevated COX-2 levels in a time-dependent manner. Angiotensin-II receptor blocker, losartan, diminished uric-acid-induced COX-2 elevation. Uric acid also increased superoxide anion level in VSMCs. Uric acid plays an important role in CVD pathogenesis by inducing inflammatory COX-2 and ROS pathways. This is the first study demonstrating losartan's ability to reduce uric-acid-induced COX-2 elevation.

Cytochrome b5 reductase is the component from neuronal synaptic plasma membrane vesicles that generates superoxide anion upon stimulation by cytochrome c.

PubMed

Samhan-Arias, Alejandro K; Fortalezas, Sofia; Cordas, Cristina M; Moura, Isabel; Moura, José J G; Gutierrez-Merino, Carlos

2018-05-01

In this work, we measured the effect of cytochrome c on the NADH-dependent superoxide anion production by synaptic plasma membrane vesicles from rat brain. In these membranes, the cytochrome c stimulated NADH-dependent superoxide anion production was inhibited by antibodies against cytochrome b 5 reductase linking the production to this enzyme. Measurement of the superoxide anion radical generated by purified recombinant soluble and membrane cytochrome b 5 reductase corroborates the production of the radical by different enzyme isoforms. In the presence of cytochrome c, a burst of superoxide anion as well as the reduction of cytochrome c by cytochrome b 5 reductase was measured. Complex formation between both proteins suggests that cytochrome b 5 reductase is one of the major partners of cytochrome c upon its release from mitochondria to the cytosol during apoptosis. Superoxide anion production and cytochrome c reduction are the consequences of the stimulated NADH consumption by cytochrome b 5 reductase upon complex formation with cytochrome c and suggest a major role of this enzyme as an anti-apoptotic protein during cell death. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Genetic modification of human mesenchymal stem cells helps to reduce adiposity and improve glucose tolerance in an obese diabetic mouse model.

PubMed

Sen, Sabyasachi; Domingues, Cleyton C; Rouphael, Carol; Chou, Cyril; Kim, Chul; Yadava, Nagendra

2015-12-09

Human mesenchymal stem cells (MSCs) are multipotent cells that can differentiate into fat, muscle, bone and cartilage cells. Exposure of subcutaneous abdominal adipose tissue derived AD-MSCs to high glucose (HG) leads to superoxide accumulation and up-regulation of inflammatory molecules. Our aim was to inquire how HG exposure affects MSCs differentiation and whether the mechanism is reversible. We exposed human adipose tissue derived MSCs to HG (25 mM) and compared it to normal glucose (NG, 5.5 mM) exposed cells at 7, 10 and 14 days. We examined mitochondrial superoxide accumulation (Mitosox-Red), cellular oxygen consumption rate (OCR, Seahorse) and gene expression. HG increased reactive superoxide (ROS) accumulation noted by day 7 both in cytosol and mitochondria. The OCR between the NG and HG exposed groups however did not change until 10 days at which point OCR of HG exposed cells were reduced significantly. We noted that HG exposure upregulated mRNA expression of adipogenic (PPARG, FABP-4, CREBP alpha and beta), inflammatory (IL-6 and TNF alpha) and antioxidant (SOD2 and Catalase) genes. Next, we used AdSOD2 to upregulate SOD2 prior to HG exposure and thereby noted reduction in superoxide generation. SOD2 upregulation helped reduce mRNA over-expression of PPARG, FABP-4, IL-6 and TNFα. In a series of separate experiments, we delivered the eGFP and SOD2 upregulated MSCs (5 days post ex-vivo transduction) and saline intra-peritoneally (IP) to obese diabetic (db/db) mice. We confirmed homing-in of eGFP labeled MSCs, delivered IP, to different inflamed fat pockets, particularly omental fat. Mice receiving SOD2-MSCs showed progressive reduction in body weight and improved glucose tolerance (GTT) at 4 weeks, post MSCs transplantation compared to the GFP-MSC group (control). High glucose evokes superoxide generation, OCR reduction and adipogenic differentiation. Mitochondrial superoxide dismutase upregulation quenches excess superoxide and reduces adipocyte inflammation. Delivery of superoxide dismutase (SOD2) using MSCs as a gene delivery vehicle reduces inflammation and improves glucose tolerance in vivo. Suppression of superoxide production and adipocyte inflammation using mitochondrial superoxide dismutase may be a novel and safe therapeutic tool to combat hyperglycemia mediated effects.

Iodide oxidation and iodine reduction mediated by horseradish peroxidase in the presence of ethylenediaminetetraacetic acid (EDTA): the superoxide effect.

PubMed

Chang, H C; Bumpus, J A

2001-04-01

Ethylenediaminetetraacetic acid (EDTA) is an inhibitor of iodide (I-) oxidation that is catalyzed by horseradish peroxidase (HRP). HRP-mediated iodine (I2) reduction and triiodide (I3+) disappearance occur in the presence of this inhibitor. It is interesting that in the presence of EDTA, HRP produces superoxide radical, a reactive oxygen species that is required for iodine reduction. Substitution of potassium superoxide (KO2) or a biochemical superoxide generating system (xanthine/xanthine oxidase) for HRP and H2O2 in the reaction mixture also can reduce iodine to iodide. Thus, iodine reduction mediated by HRP occurs because HRP is able to mediate the formation of superoxide in the presence of EDTA and H2O2. Although superoxide is able to mediate iodine reduction directly, other competing reactions appear to be more important. For example, high concentrations (mM range) of EDTA are required for efficient iodine reduction in this system. Under such conditions, the concentration (microM range) of contaminating EDTA-Fe(III) becomes catalytically important. In the presence of superoxide, EDTA-Fe(III) is reduced to EDTA-Fe(II), which is able to reduce iodine and form triiodide rapidly. Also of importance is the fact that EDTA-Fe(II) reacts with hydrogen peroxide to form hydroxyl radical. Hydroxyl radical involvement is supported by the fact that a wide variety of hydroxyl radical (OH) scavengers can inhibit HRP dependent iodine reduction in the presence of EDTA and hydrogen peroxide.

Enhancement of amphotericin B activity against Candida albicans by superoxide radical.

PubMed

Okamoto, Yuichi; Aoki, Shigeji; Mataga, Izumi

2004-07-01

This study aimed to examine the involvement of oxidative damage in amphotericin B (AmB) activity against Candida albicans using the superoxide (O2-) generator paraquat (PQ). The effects of PQ on AmB activities against growth, viability, membrane permeability and respiration were examined in a wild-type parent strain (K) and a respiration-deficient mutant (KRD-19) since PQ-induced superoxide generation depends on respiration. In the parent strain, the minimal inhibitory concentration (MIC) of AmB, 0.25 microg/ml, tested with a liquid culture was lowered to 0.025 microg/ml by 1 mM PQ. Such a PQ-induced decrease in the MIC value of AmB was minimal in the mutant. Similar PQ-induced enhancement of AmB activity toward the parent strain was also observed with growth on an agar medium. In viability tests, when candidal cells were exposed to AmB (0.1 microg/ml) for I h, the lethality of AmB was enhanced by 1 mM PQ only in the parent strain. Exogenous superoxide dismutase and catalase failed to diminish the enhancing effect of PQ on the growth inhibitory activity of AmB in the parent strain, suggesting an interaction between superoxide and AmB in candidal cells. The enhancement of AmB activity by PQ, observed preferentially in the wild-type strain, can be explained by extensive superoxide generation depending on respiration. These results suggest that oxidative damage induced by superoxide is involved in AmB activity against C. albicans.

Importance of Extracellular Processes in the Oxygen Enhancement of Radiation Lethality.

DTIC Science & Technology

1982-03-08

radical oxygen toxicity superoxide dismutases methyl viologen hydroxyl radical pyocyanine o. Lactobacillus plantarum manganese Streptococcus sanguis gene...Against Oxygen Toxicity in Lactobacillus plantarum . F. S. Archibald and I. Fridovich. Superoxide Dismutases: Detoxication of a Free Radical. H. M. Hassan...S. Archibald and I. Fridovich 7 Investigations of the State of the Manganese in Lactobacillus plantarum . F. S. Archibald and I. Fridovich Superoxide

Production of superoxide in chloroplast thylakoid membranes ESR study with cyclic hydroxylamines of different lipophilicity.

PubMed

Kozuleva, Marina; Klenina, Irina; Proskuryakov, Ivan; Kirilyuk, Igor; Ivanov, Boris

2011-04-06

Accumulation of nitroxide radicals, DCP· or TMT·, under illumination of a thylakoid suspension containing either hydrophilic, DCP-H, or lipophilic, TMT-H, cyclic hydroxylamines that have high rate constants of the reaction with superoxide radicals, was measured using ESR. A slower accumulation of TMT· in contrast with DCP· accumulation was explained by re-reduction of TMT· by the carriers of the photosynthetic electron transport chain within the membrane. Superoxide dismutase suppressed TMT· accumulation to a lesser extent than DCP· accumulation. The data are interpreted as evidencing the production of intramembrane superoxide in thylakoids. Copyright © 2011 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Fluoride Increases Superoxide Production and Impairs the Respiratory Chain in ROS 17/2.8 Osteoblastic Cells

PubMed Central

Fina, Brenda Lorena; Lombarte, Mercedes; Rigalli, Juan Pablo; Rigalli, Alfredo

2014-01-01

It is known that fluoride produces oxidative stress. Inflammation in bone tissue and an impairment of the respiratory chain of liver have been described in treatments with fluoride. Whether the impairment of the respiratory chain and oxidative stress are related is not known. The aim of this work was to study the effects of fluoride on the production of superoxide radical, the function of the respiratory chain and the increase in oxidative stress in ROS 17/2.8 osteoblastic cells. We measured the effect of fluoride (100 µM) on superoxide production, oxygen consumption, lipid peroxidation and antioxidant enzymes activities of cultured cells following the treatment with fluoride. Fluoride decreased oxygen consumption and increased superoxide production immediately after its addition. Furthermore, chronic treatment with fluoride increased oxidative stress status in osteoblastic cells. These results indicate that fluoride could damage bone tissue by inhibiting the respiratory chain, increasing the production of superoxide radicals and thus of the others reactive oxygen species. PMID:24964137

NADH induces the generation of superoxide radicals in leaf peroxisomes. [Pisum sativum L

DOE Office of Scientific and Technical Information (OSTI.GOV)

del Rio, L.A.; Sandalio, L.M.; Palma, J.M.

1989-03-01

In peroxisomes isolated from pea leaves (Pisum sativum L.) the production of superoxide free radicals (O{sub 2}{sup {minus}}) by xanthine and NADH was investigated. In peroxisomal membranes, 100 micromolar NADH induced the production of O{sub 2}{sup {minus}} radicals. In the soluble fractions of peroxisomes, no generation of O{sub 2}{sup {minus}} radicals was observed by incubation with either NADH or xanthine, although xanthine oxidase was found located predominantly in the matrix of peroxisomes. The failure of xanthine to induce superoxide generation was probably due to the inability to fully suppress the endogenous Mn-superoxide dismutase activity by inhibitors which were inactive againstmore » xanthine oxidase. The generation of superoxide radicals in leaf peroxisomes together with the recently described production of these oxygen radicals in glyoxysomes suggests that O{sub 2}{sup {minus}} generation could be a common metabolic property of peroxisomes and further supports the existence of active oxygen-related roles for peroxisomes in cellular metabolism.« less

Nitration and inactivation of manganese superoxide dismutase in chronic rejection of human renal allografts.

PubMed Central

MacMillan-Crow, L A; Crow, J P; Kerby, J D; Beckman, J S; Thompson, J A

1996-01-01

Inflammatory processes in chronic rejection remain a serious clinical problem in organ transplantation. Activated cellular infiltrate produces high levels of both superoxide and nitric oxide. These reactive oxygen species interact to form peroxynitrite, a potent oxidant that can modify proteins to form 3-nitrotyrosine. We identified enhanced immunostaining for nitrotyrosine localized to tubular epithelium of chronically rejected human renal allografts. Western blot analysis of rejected tissue demonstrated that tyrosine nitration was restricted to a few specific polypeptides. Immunoprecipitation and amino acid sequencing techniques identified manganese superoxide dismutase, the major antioxidant enzyme in mitochondria, as one of the targets of tyrosine nitration. Total manganese superoxide dismutase protein was increased in rejected kidney, particularly in the tubular epithelium; however, enzymatic activity was significantly decreased. Exposure of recombinant human manganese superoxide dismutase to peroxynitrite resulted in a dose-dependent (IC50 = 10 microM) decrease in enzymatic activity and concomitant increase in tyrosine nitration. Collectively, these observations suggest a role for peroxynitrite during development and progression of chronic rejection in human renal allografts. In addition, inactivation of manganese superoxide dismutase by peroxynitrite may represent a general mechanism that progressively increases the production of peroxynitrite, leading to irreversible oxidative injury to mitochondria. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:8876227

Hypoglycemic neuronal death is triggered by glucose reperfusion and activation of neuronal NADPH oxidase

PubMed Central

Suh, Sang Won; Gum, Elizabeth T.; Hamby, Aaron M.; Chan, Pak H.; Swanson, Raymond A.

2007-01-01

Hypoglycemic coma and brain injury are potential complications of insulin therapy. Certain neurons in the hippocampus and cerebral cortex are uniquely vulnerable to hypoglycemic cell death, and oxidative stress is a key event in this cell death process. Here we show that hypoglycemia-induced oxidative stress and neuronal death are attributable primarily to the activation of neuronal NADPH oxidase during glucose reperfusion. Superoxide production and neuronal death were blocked by the NADPH oxidase inhibitor apocynin in both cell culture and in vivo models of insulin-induced hypoglycemia. Superoxide production and neuronal death were also blocked in studies using mice or cultured neurons deficient in the p47phox subunit of NADPH oxidase. Chelation of zinc with calcium disodium EDTA blocked both the assembly of the neuronal NADPH oxidase complex and superoxide production. Inhibition of the hexose monophosphate shunt, which utilizes glucose to regenerate NADPH, also prevented superoxide formation and neuronal death, suggesting a mechanism linking glucose reperfusion to superoxide formation. Moreover, the degree of superoxide production and neuronal death increased with increasing glucose concentrations during the reperfusion period. These results suggest that high blood glucose concentrations following hypoglycemic coma can initiate neuronal death by a mechanism involving extracellular zinc release and activation of neuronal NADPH oxidase. PMID:17404617

Yeast and Mammalian Metallothioneins Functionally Substitute for Yeast Copper-Zinc Superoxide Dismutase

NASA Astrophysics Data System (ADS)

Tamai, Katherine T.; Gralla, Edith B.; Ellerby, Lisa M.; Valentine, Joan S.; Thiele, Dennis J.

1993-09-01

Copper-zinc superoxide dismutase catalyzes the disproportionation of superoxide anion to hydrogen peroxide and dioxygen and is thought to play an important role in protecting cells from oxygen toxicity. Saccharomyces cerevisiae strains lacking copper-zinc superoxide dismutase, which is encoded by the SOD1 gene, are sensitive to oxidative stress and exhibit a variety of growth defects including hypersensitivity to dioxygen and to superoxide-generating drugs such as paraquat. We have found that in addition to these known phenotypes, SOD1-deletion strains fail to grow on agar containing the respiratory carbon source lactate. We demonstrate here that expression of the yeast or monkey metallothionein proteins in the presence of copper suppresses the lactate growth defect and some other phenotypes associated with SOD1-deletion strains, indicating that copper metallothioneins substitute for copper-zinc superoxide dismutase in vivo to protect cells from oxygen toxicity. Consistent with these results, we show that yeast metallothionein mRNA levels are dramatically elevated under conditions of oxidative stress. Furthermore, in vitro assays demonstrate that yeast metallothionein, purified or from whole-cell extracts, exhibits copper-dependent antioxidant activity. Taken together, these data suggest that both yeast and mammalian metallothioneins may play a direct role in the cellular defense against oxidative stress by functioning as antioxidants.

Superoxide and nitric oxide production by Kupffer cells in rats with obstructive jaundice: effect of internal and external drainage.

PubMed

Li, Wen; Chan, Angus C W; Lau, James Y W; Lee, Danny W H; Ng, Enders K W; Sung, Joseph J Y; Chung, S C Sydney

2004-02-01

The role of Kupffer cells in obstructive jaundice (OJ) has not been fully understood. The aims of the present study were to measure superoxide and nitric oxide (NO) production by Kupffer cells in experimental OJ in rats and to investigate the response to internal and external biliary drainage. Eighty male Sprague-Dawley rats were assigned to four groups: sham operation, OJ, and internal and external biliary drainage. Kupffer cells were isolated on day 7 in the sham operation and OJ group, and on day 7 after drainage procedures. Cells were cultured with or without lipopolysaccharide (LPS). Superoxide production was quantified in cultured Kupffer cells at 2 h and 48 h, respectively, after cell isolation using the superoxide dismutase inhibitable ferricytochrome c reduction method. Nitrite production in cell culture supernatants was measured 48 h later using Greiss reagents. Without LPS stimulation, Kupffer cells produced comparable superoxide and nitrite in each group (P > 0.05). With LPS stimulation, Kupffer cells in the OJ group produced significantly higher superoxide anions than the other groups (P = 0.006). Nitrite production was significantly increased in the OJ group and external biliary drainage group compared to rats in the sham operation and internal drainage groups (P < 0.01). Kupffer cells from rats with OJ produce great amounts of endotoxin-mediated oxidants. Both internal and external biliary drainage can decrease the elevated superoxide production. Internal drainage is superior to external drainage for reversing the distortional capacity of NO production by Kupffer cells.

Macroporous mesh of nanoporous gold in electrochemical monitoring of superoxide release from skeletal muscle cells.

PubMed

Banan Sadeghian, Ramin; Han, Jiuhui; Ostrovidov, Serge; Salehi, Sahar; Bahraminejad, Behzad; Ahadian, Samad; Chen, Mingwei; Khademhosseini, Ali

2017-02-15

Real-time monitoring of metabolically relevant biochemicals released in minuscule amounts is of utmost diagnostic importance. Superoxide anion as a primary member of reactive oxygen species, has physiological and pathological effects that depend on its concentration and release rate. Here we present fabrication and successfully testing of a highly sensitive electrochemical biosensor featuring a three-dimensional macroporous mesh of nanoporous gold tailored to measure the dynamics of extracellular superoxide concentration. Wide and accessible surface of the mesh combined with high porosity of the thin nanoporous gold coating enables capturing the analyte in pico- to nano-molar ranges. The mesh is functionalized with cytochrome-c (cyt-c) and incorporated as a working electrode to measure the release rate of drug-induced superoxides from C2C12 cells through a porous membrane. The device displays a considerably improved superoxide sensitivity of 7.29nAnM - 1 cm - 2 and a low level of detection of 70pM. Such sensitivity is orders of magnitude higher than any similar enzyme-based electrochemical superoxide sensor and is attributed to the facile diffusion of the analyte through the well-spread nanofeatured gold skin. Superoxide generation rates captured from monolayer myoblast cultures containing about 4×10 4 cells, varied from 1.0 to 9.0nMmin - 1 in a quasi-linear fashion as a function of drug concentration. This work provides a platform for the development of highly sensitive molecular electrochemical biosensors. Copyright © 2016 Elsevier B.V. All rights reserved.

Downstream components of RhoA required for signal pathway of superoxide formation during phagocytosis of serum opsonized zymosans in macrophages.

PubMed

Kim, Jun Sub; Kim, Jae Gyu; Jeon, Chan Young; Won, Ha Young; Moon, Mi Young; Seo, Ji Yeon; Kim, Jong Il; Kim, Jaebong; Lee, Jae Yong; Choi, Soo Young; Park, Jinseu; Yoon Park, Jung Han; Ha, Kwon Soo; Kim, Pyeung Hyeun; Park, Jae Bong

2005-12-31

Rac1 and Rac2 are essential for the control of oxidative burst catalyzed by NADPH oxidase. It was also documented that Rho is associated with the superoxide burst reaction during phagocytosis of serum- (SOZ) and IgG-opsonized zymosan particles (IOZ). In this study, we attempted to reveal the signal pathway components in the superoxide formation regulated by Rho GTPase. Tat-C3 blocked superoxide production, suggesting that RhoA is essentially involved in superoxide formation during phagocytosis of SOZ. Conversely SOZ activated both RhoA and Rac1/2. Inhibition of RhoA-activated kinase (ROCK), an important downstream effector of RhoA, by Y27632 and myosin light chain kinase (MLCK) by ML-7 abrogated superoxide production by SOZ. Extracellular signaling-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase (MAPK) were activated during phagocytosis of SOZ, and Tat-C3 and SB203580 reduced ERK1/2 and p38 MAPK activation, suggesting that RhoA and p38 MAPK may be upstream regulators of ERK1/2. Inhibition of ERK1/2, p38 MAPK, phosphatidyl inositol 3-kinase did not block translocation of RhoA to membranes, suggesting that RhoA is upstream to these kinases. Inhibition of RhoA by Tat-C3 blocked phosphorylation of p47(PHOX). Taken together, RhoA, ROCK, p38MAPK, ERK1/2, and p47(PHOX) may be subsequently activated, leading to activation of NADPH oxidase to produce superoxide.

Acute retinal ischemia inhibits endothelium-dependent nitric oxide-mediated dilation of retinal arterioles via enhanced superoxide production.

PubMed

Hein, Travis W; Ren, Yi; Potts, Luke B; Yuan, Zhaoxu; Kuo, Enoch; Rosa, Robert H; Kuo, Lih

2012-01-03

Because retinal vascular disease is associated with ischemia and increased oxidative stress, the vasodilator function of retinal arterioles was examined after retinal ischemia induced by elevated intraocular pressure (IOP). The role of superoxide anions in the development of vascular dysfunction was assessed. IOP was increased and maintained at 80 to 90 mm Hg for 30, 60, or 90 minutes by infusing saline into the anterior chamber of a porcine eye. The fellow eye with normal IOP (10-20 mm Hg) served as control. In some pigs, superoxide dismutase mimetic TEMPOL (1 mM) or vehicle (saline) was injected intravitreally before IOP elevation. After enucleation, retinal arterioles were isolated and pressurized without flow for functional analysis by recording diameter changes using videomicroscopic techniques. Dihydroethidium (DHE) was used to detect superoxide production in isolated retinal arterioles. Isolated retinal arterioles developed stable basal tone and the vasodilations to endothelium-dependent nitric oxide (NO)-mediated agonists bradykinin and L-lactate were significantly reduced only by 90 minutes of ischemia. However, vasodilation to endothelium-independent NO donor sodium nitroprusside was unaffected after all time periods of ischemia. DHE staining showed that 90 minutes of ischemia significantly increased superoxide levels in retinal arterioles. Intravitreal injection of membrane-permeable radical scavenger but not vehicle before ischemia prevented elevation of vascular superoxide and preserved bradykinin-induced dilation. Endothelium-dependent NO-mediated dilation of retinal arterioles is impaired by 90 minutes of ischemia induced by elevated IOP. The inhibitory effect appears to be mediated by the alteration of NO signaling via vascular superoxide.

Anti-inflammatory activity of Chios mastic gum is associated with inhibition of TNF-alpha induced oxidative stress

PubMed Central

2011-01-01

Background Gum of Chios mastic (Pistacia lentiscus var. chia) is a natural antimicrobial agent that has found extensive use in pharmaceutical products and as a nutritional supplement. The molecular mechanisms of its anti-inflammatory activity, however, are not clear. In this work, the potential role of antioxidant activity of Chios mastic gum has been evaluated. Methods Scavenging of superoxide radical was investigated by electron spin resonance and spin trapping technique using EMPO spin trap in xanthine oxidase system. Superoxide production in endothelial and smooth muscle cells stimulated with TNF-α or angiotensin II and treated with vehicle (DMSO) or mastic gum (0.1-10 μg/ml) was measured by DHE and HPLC. Cellular H2O2 was measured by Amplex Red. Inhibition of protein kinase C (PKC) with mastic gum was determined by the decrease of purified PKC activity, by inhibition of PKC activity in cellular homogenate and by attenuation of superoxide production in cells treated with PKC activator phorbol 12-myristate 13-acetate (PMA). Results Spin trapping study did not show significant scavenging of superoxide by mastic gum itself. However, mastic gum inhibited cellular production of superoxide and H2O2 in dose dependent manner in TNF-α treated rat aortic smooth muscle cells but did not affect unstimulated cells. TNF-α significantly increased the cellular superoxide production by NADPH oxidase, while mastic gum completely abolished this stimulation. Mastic gum inhibited the activity of purified PKC, decreased PKC activity in cell homogenate, and attenuated superoxide production in cells stimulated with PKC activator PMA and PKC-dependent angiotensin II in endothelial cells. Conclusion We suggest that mastic gum inhibits PKC which attenuates production of superoxide and H2O2 by NADPH oxidases. This antioxidant property may have direct implication to the anti-inflammatory activity of the Chios mastic gum. PMID:21645369

Permeation of superoxide anion through the bilayer of vesicles of a synthetic amphiphile.

PubMed

Gomes, L F; Cuccovia, I M; Chaimovich, H; Barbieri, D H; Politi, M J

1993-10-10

Large unilamellar vesicles, prepared with dioctadecyldimethylammonium chloride, entrap nitroblue tetrazolium. Addition of solid KO2, or production of superoxide anion by riboflavin photolysis, to nitroblue tetrazolium-containing dioctadecyldimethylammonium vesicles results in the formation of monoformazan above the phase-transition temperature of the bilayer. Below the phase-transition temperature the yield of monoformazan is negligible. These results demonstrate that superoxide anion permeates vesicles above the phase-transition temperature of the bilayer.

The preparation of calcium superoxide from calcium peroxide diperoxyhydrate

NASA Technical Reports Server (NTRS)

Ballou, E. V.; Wood, P. C.; Spitze, L. A.; Wydeven, T.

1977-01-01

There is interest in solid materials containing a high percentage of stored oxygen for use in emergency breathing apparatus for miners and as auxiliary oxygen sources for astronauts. In theory, the amount of available oxygen in calcium superoxide, Ca(O2)2 is higher than in potassium superoxide, KO2, and its availability during use should be unhindered by the formation of a low melting and hydrous coating. The decomposition of solid calcium peroxide diperoxyhydrate, CaO2.2H2O2 has been studied, using an apparatus which allows good control of the critical reaction parameters. Samples have been prepared showing apparent superoxide contents in excess of those previously reported and higher than the theoretical 58.4% expected from a disproportionation reaction.

Superoxide (O2.-) accumulation contributes to symptomless (type I) nonhost resistance of plants to biotrophic pathogens.

PubMed

Künstler, András; Bacsó, Renáta; Albert, Réka; Barna, Balázs; Király, Zoltán; Hafez, Yaser Mohamed; Fodor, József; Schwarczinger, Ildikó; Király, Lóránt

2018-05-07

Nonhost resistance is the most common form of disease resistance exhibited by plants against most pathogenic microorganisms. Type I nonhost resistance is symptomless (i.e. no macroscopically visible cell/tissue death), implying an early halt of pathogen growth. The timing/speed of defences is much more rapid during type I nonhost resistance than during type II nonhost and host ("gene-for-gene") resistance associated with a hypersensitive response (localized necrosis, HR). However, the mechanism(s) underlying symptomless (type I) nonhost resistance is not entirely understood. Here we assessed accumulation dynamics of the reactive oxygen species superoxide (O 2 .- ) during interactions of plants with a range of biotrophic and hemibiotrophic pathogens resulting in susceptibility, symptomless nonhost resistance or host resistance with HR. Our results show that the timing of macroscopically detectable superoxide accumulation (1-4 days after inoculation, DAI) is always associated with the speed of the defense response (symptomless nonhost resistance vs. host resistance with HR) in inoculated leaves. The relatively early (1 DAI) superoxide accumulation during symptomless nonhost resistance of barley to wheat powdery mildew (Blumeria graminis f. sp. tritici) is localized to mesophyll chloroplasts of inoculated leaves and coupled to enhanced NADPH oxidase (EC 1.6.3.1) activity and transient increases in expression of genes regulating superoxide levels and cell death (superoxide dismutase, HvSOD1 and BAX inhibitor-1, HvBI-1). Importantly, the partial suppression of symptomless nonhost resistance of barley to wheat powdery mildew by heat shock (49 °C, 45 s) and antioxidant (SOD and catalase) treatments points to a functional role of superoxide in symptomless (type I) nonhost resistance. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

Involvement of the chloroplast plastoquinone pool in the Mehler reaction.

PubMed

Vetoshkina, Daria V; Ivanov, Boris N; Khorobrykh, Sergey A; Proskuryakov, Ivan I; Borisova-Mubarakshina, Maria M

2017-09-01

Light-dependent oxygen reduction in the photosynthetic electron transfer chain, i.e. the Mehler reaction, has been studied using isolated pea thylakoids. The role of the plastoquinone pool in the Mehler reaction was investigated in the presence of dinitrophenyl ether of 2-iodo-4-nitrothymol (DNP-INT), the inhibitor of plastohydroquinone oxidation by cytochrome b6/f complex. Oxygen reduction rate in the presence of DNP-INT was higher than in the absence of the inhibitor in low light at pH 6.5 and 7.6, showing that the capacity of the plastoquinone pool to reduce molecular oxygen in this case exceeded that of the entire electron transfer chain. In the presence of DNP-INT, appearance of superoxide anion radicals outside thylakoid membrane represented approximately 60% of the total superoxide anion radicals produced. The remaining 40% of the produced superoxide anion radicals was suggested to be trapped by plastohydroquinone molecules within thylakoid membrane, leading to the formation of hydrogen peroxide (H 2 O 2 ). To validate the reaction of superoxide anion radical with plastohydroquinone, xanthine/xanthine oxidase system was integrated with thylakoid membrane in order to generate superoxide anion radical in close vicinity of plastohydroquinone. Addition of xanthine/xanthine oxidase to the thylakoid suspension resulted in a decrease in the reduction level of the plastoquinone pool in the light. The obtained data provide additional clarification of the aspects that the plastoquinone pool is involved in both reduction of oxygen to superoxide anion radicals and reduction of superoxide anion radicals to H 2 O 2 . Significance of the plastoquinone pool involvement in the Mehler reaction for the acclimation of plants to light conditions is discussed. © 2017 Scandinavian Plant Physiology Society.

Effect of sildenafil citrate and a nitric oxide donating sildenafil derivative, NCX 911, on cavernosal relaxation and superoxide formation in hypercholesterolaemic rabbits.

PubMed

Shukla, Nilima; Jones, Robert; Persad, Raj; Angelini, Gianni D; Jeremy, Jamie Y

2005-07-11

Hypercholesterolaemia promotes erectile dysfunction through increased superoxide formation and negation of nitric oxide (NO) bioactivity in cavernosal tissue. The source of superoxide has not been clearly defined, however. Sildenafil (Viagra), the standard therapy for erectile dysfunction, may also be rendered more effective by the presence of an NO donor. One drug that intrinsically fulfils this criterion is sildenafil nitrate (NCX 911), an NO donating derivative of sildenafil. The objective of this study, therefore, was to determine the source of superoxide and its effect on erectile function in corpus cavernosum from hypercholesterolaemic rabbits and to determine whether NCX 911 confers an improvement over sildenafil citrate in this model. Hypercholesterolaemia elicited an increase in superoxide formation by rabbit cavernosal tissue and a reduction of carbachol-stimulated relaxation both of which were reversed by diphenylene iodonium chloride and apocynin (NADPH oxidase inhibitors). In response to sodium nitroprusside, hypercholesterolaemia also caused an attenuation of cavernosal relaxation which was not reversed with NADPH oxidase inhibitors. Both sildenafil citrate and NCX 911 significantly reversed impaired carbachol-stimulated relaxation and inhibited superoxide formation by cavernosal tissue from hypercholesterolaemic rabbits, NCX 911 being more potent. NCX 911 also augmented cavernosal cGMP levels, an effect blocked by the guanylyl cyclase inhibitor, 1H-{1,2,4}oxadiazolo {4,3-a}quinoxalin-1-one (ODQ). These data demonstrate that hypercholesterolaemia promotes erectile dysfunction through an augmentation of superoxide derived from NADPH oxidase in cavernosal tissue. It also indicates that NO donating sildenafil may be therapeutically more beneficial than conventional sildenafil in treating erectile dysfunction with an oxidative stress-related aetiology.

In vitro antimicrobial activity of Medilox® super-oxidized water.

PubMed

Gunaydin, Murat; Esen, Saban; Karadag, Adil; Unal, Nevzat; Yanik, Keramettin; Odabasi, Hakan; Birinci, Asuman

2014-07-14

Super-oxidized water is one of the broad spectrum disinfectants, which was introduced recently. There are many researches to find reliable chemicals which are effective, inexpensive, easy to obtain and use, and effective for disinfection of microorganisms leading hospital infections. Antimicrobial activity of super-oxidized water is promising. The aim of this study was to investigate the in-vitro antimicrobial activity of different concentrations of Medilox® super-oxidized water that is approved by the Food and Drug Administration (FDA) as high level disinfectant. In this study, super-oxidized water obtained from Medilox® [Soosan E & C, Korea] device, which had been already installed in our hospital, was used. Antimicrobial activities of different concentrations of super-oxidized water (1/1, 1/2, 1/5, 1/10, 1/20, 1/50, 1/100) at different exposure times (1, 2, 5, 10, 30 min) against six ATCC strains, eight antibiotic resistant bacteria, yeasts and molds were evaluated using qualitative suspension test. Dey-Engley Neutralizing Broth [Sigma-Aldrich, USA] was used as neutralizing agent. Medilox® was found to be effective against all standard strains (Acinetobacter baumannii 19606, Escherichia coli 25922, Enterococcus faecalis 29212, Klebsiella pneumoniae 254988, Pseudomonas aeruginosa 27853, Staphylococcus aureus 29213), all clinical isolates (Acinetobacter baumannii, Escherichia coli, vancomycin-resistant Enterococcus faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, Bacillus subtilis, Myroides spp.), and all yeastsat 1/1 dilution in ≥1 minute. It was found to be effective on Aspergillus flavus at 1/1 dilution in ≥2 minutes and on certain molds in ≥5 minutes. Medilox® super-oxidized water is a broad spectrum, on-site producible disinfectant, which is effective on bacteria and fungi and can be used for the control of nosocomial infection.

Ceruloplasmin reduces the adhesion and scavenges superoxide during the interaction of activated polymorphonuclear leukocytes with endothelial cells.

PubMed Central

Broadley, C.; Hoover, R. L.

1989-01-01

The plasma protein, ceruloplasmin, has been implicated as an anti-inflammatory agent, although this property has not been demonstrated unequivocally in vivo. The role of this protein in an in vitro system of cultured endothelial cells and polymorphonuclear leukocytes (PMNs) was investigated. One of the initial steps in an inflammatory response is increased adhesion between PMNs and the endothelial lining of the blood vessels. The results showed that ceruloplasmin interferes with this process and reduces the number of phorbol myristate acetate-activated leukocytes that adhere to endothelium. Preincubation of either the activated PMNs or the endothelium with ceruloplasmin did not produce the same results, suggesting that the continuous presence of ceruloplasmin is required. During attachment PMNs become activated and release a variety of substances, including toxic oxygen species such as superoxide and hydrogen peroxide. In the in vitro system used in this study no injury occurred to the endothelial cells, as measured by 51Cr release, when activated PMNs were added with ceruloplasmin. The data show that ceruloplasmin reduced, in a dose dependent manner, the levels of superoxide produced by the activated PMNs, further supporting ceruloplasmin's previously reported role as a scavenger of superoxide. Ceruloplasmin also reduced the levels of superoxide when activated PMNs were in contact with endothelial cells. Although ceruloplasmin interfered with the copper-dependent scavenger enzyme, superoxide dismutase (SOD), in a cell-free system, ceruloplasmin had no effect on SOD in intact endothelial cells. These results suggest that ceruloplasmin may act as an anti-inflammatory agent by reducing the number of PMNs attaching to endothelium and by acting as an extracellular scavenger of superoxide. PMID:2552811

Prolonged exposure of resveratrol induces reactive superoxide species-independent apoptosis in murine prostate cells.

PubMed

Kumar, Sanjay; Stokes, James; Singh, Udai P; Scissum-Gunn, Karyn; Singh, Rajesh; Manne, Upender; Mishra, Manoj K

2017-10-01

Nitric oxide, a signaling molecule, inhibits mitochondrial respiration by binding with cytochrome c oxidase, resulting in elevated production of reactive superoxide species (reactive oxygen and nitrogen) in the mitochondria and increased susceptibility to cell death. Generation of mitochondrial superoxide species can be suppressed by natural compounds such as resveratrol, a dietary polyphenol found in the skin of red fruits. In various cancer cells, resveratrol shows anti-oxidant and cancer preventive properties. Since, the effect of resveratrol on reactive superoxide species-independent apoptosis in prostate cancer cells is not well illustrated; therefore, we investigated this phenomenon in TRAMP murine prostate cancer cells. To accomplish this, TRAMP cells were incubated with resveratrol, resveratrol + DETA-NONOate, DETA-NONOate (nitric oxide donor), resveratrol + L-NMMA, or L-NMMA (nitric oxide inhibitor) for 48 h, and reactive superoxide species in the mitochondria and culture supernatant were measured. In addition, the mitochondrial membrane potential, cell viability, expression of apoptotic markers (Bax and Bcl2), γ-H2A.x, p53, and caspase-3 was determined. We found that resveratrol suppressed reactive superoxide species such as reactive oxygen species in the mitochondria and nitric oxide in culture supernatant when compared to the DETA-NONOate treatment and disrupted the mitochondrial membrane potential. Resveratrol also reduced cell viability, altered the expression of apoptotic markers (Bax and Bcl2), and increased expression of γ-H2A.x (indicative marker of DNA fragmentation) and p53 (a critical DNA damage response protein). However, there was no appreciable modulation of the caspase-3. Therefore, our data suggest that resveratrol induces superoxide species-independent apoptosis and may act as a therapeutic agent against prostate cancer.

Temperature and Light Effects on Extracellular Superoxide Production by Algal and Bacterial Symbionts in Corals: Implications for Coral Bleaching

NASA Astrophysics Data System (ADS)

Brighi, C.; Diaz, J. M.; Apprill, A.; Hansel, C. M.

2014-12-01

Increased surface seawater temperature due to global warming is one of the main causes of coral bleaching, a phenomenon in which corals lose their photosynthetic algae. Light and temperature induced production of superoxide and other reactive oxygen species (ROS) by these symbiotic algae has been implicated in the breakdown of their symbiotic association with the coral host and subsequent coral bleaching. Nevertheless, a direct link between Symbiodinium ROS production and coral bleaching has not been demonstrated. In fact, given the abundance and diversity of microorganisms within the coral holobiont, the concentration and fluxes of ROS within corals may involve several microbial sources and sinks. Here, we explore the role of increased light and temperature on superoxide production by coral-derived cultures of Symbiodinium algae and Oceanospirillales bacteria of the genus Endozoicomonas, which are globally common and abundant associates of corals. Using a high sensitivity chemiluminescent technique, we find that heat stress (exposure to 34°C vs. 23°C for 2hr or 24hr) has no significant effect on extracellular superoxide production by Symbiodinium isolates within clades B and C, regardless of the level of light exposure. Exposure to high light, however, increased superoxide production by these organisms at both 34°C and 23°C. On the other hand, extracellular superoxide production by Endozoicomonas bacteria tested under the same conditions was stimulated by the combined effects of thermal and light stress. The results of this research suggest that the sources and physical triggers for biological superoxide production within corals are more complex than currently assumed. Thus, further investigations into the biological processes controlling ROS dynamics within corals are required to improve our understanding of the mechanisms underpinning coral bleaching and to aid in the development of mitigation strategies.

Overproduction of Petunia Chloroplastic Copper/Zinc Superoxide Dismutase Does Not Confer Ozone Tolerance in Transgenic Tobacco 1

PubMed Central

Pitcher, Lynne H.; Brennan, Eileen; Hurley, Arthur; Dunsmuir, Pamela; Tepperman, James M.; Zilinskas, Barbara A.

1991-01-01

Transgenic tobacco (Nicotiana tabacum cultivar W38) plants that overproduce petunia chloroplastic Cu/Zn superoxide dismutase were exposed to ozone dosages that injure control tobacco plants. Based on foliar injury ratings, there was no consistent protection provided to the transgenic plants. These data indicate that an increase in the chloroplastic Cu/Zn superoxide dismutase alone is not sufficient to reduce ozone toxicity. ImagesFigure 1 PMID:16668407

Net superoxide levels: steeper increase with activity in cooler female and hotter male lizards.

PubMed

Ballen, Cissy; Healey, Mo; Wilson, Mark; Tobler, Michael; Wapstra, Erik; Olsson, Mats

2012-03-01

Ectotherms increase their body temperature in response to ambient heat, thereby elevating their metabolic rate. An often inferred consequence of this is an overall upregulation of gene expression and energetic expenditure, and a concomitant increased production of reactive oxygen species (e.g. superoxide) and, perhaps, a shortened lifespan. However, recent work shows that this may be a superficial interpretation. For example, sometimes a reduced temperature may in fact trigger up-regulation of gene expression. We studied temperature and associated activity effects in male and female Australian painted dragon lizards (Ctenophorus pictus) by allowing the lizards to bask for 4 h versus 12 h, and scoring their associated activity (inactive versus active basking and foraging). As predicted, long-basking lizards (hereafter 'hot') showed heightened activity in both sexes, with a more pronounced effect in females. We then tested for sex-specific effects of basking treatment and activity levels on the increase in net levels of superoxide. In males, short-baskers (hereafter 'cold') had significantly more rapidly decreasing levels of superoxide per unit increasing activity than hot males. In females, however, superoxide levels increased faster with increasing activity in the cold than in the hot basking treatment, and females earlier in the ovarian cycle had lower superoxide levels than females closer to ovulation. In short, males and females differ in how their levels of reactive oxygen species change with temperature-triggered activity.

Influence of cigarette smoking on blood and salivary super oxide dismutase levels among smokers and non-smokers.

PubMed

Reddy, Sudhakara; Swapna, Lingam Amara; Ramesh, Tatipudi; Singh, Takur Rajesh; Pradeep, Koppolu

2012-11-01

To determine the influence of smoking on the blood and salivary superoxide dismutase levels among smokers, and to demonstrate the significance in alterations in the levels of superoxide dismutase in association with patient age, periodontal disease status, and duration and smoking frequency. Sixty healthy male patients (aged 20-60 years) constituted the target population. Blood and saliva samples were collected, and the periodontal index was measured using a Community Periodontal Index probe. Blood and salivary superoxide dismutase levels were calculated with the reagents prepared, and values were measured in a UV spectrophotometer. There was a significant decrease in mean superoxide dismutase levels with an increase in age and smoking duration and frequency (0.23-0.05 U/mL). There was a range of 0.31-0.06 U/mL variation in the mean superoxide dismutase levels as the periodontal disease condition deteriorated. There was a significant reduction in the superoxide dismutase levels in the blood and saliva of smokers with increased duration and frequency of smoking, and as the periodontal disease condition worsened. Thus, this study emphasizes the importance of saliva as an easy, non-invasive procedure in the diagnosis of patients who are more prone to precancerous lesions and conditions, and its importance in patient education and motivation programs for smoking cessation. © 2011 Blackwell Publishing Asia Pty Ltd.

Superoxide Triggers an Acid Burst in Saccharomyces cerevisiae to Condition the Environment of Glucose-starved Cells*

PubMed Central

Baron, J. Allen; Laws, Kaitlin M.; Chen, Janice S.; Culotta, Valeria C.

2013-01-01

Although yeast cells grown in abundant glucose tend to acidify their extracellular environment, they raise the pH of the environment when starved for glucose or when grown strictly with non-fermentable carbon sources. Following prolonged periods in this alkaline phase, Saccharomyces cerevisiae cells will switch to producing acid. The mechanisms and rationale for this “acid burst” were unknown. Herein we provide strong evidence for the role of mitochondrial superoxide in initiating the acid burst. Yeast mutants lacking the mitochondrial matrix superoxide dismutase (SOD2) enzyme, but not the cytosolic Cu,Zn-SOD1 enzyme, exhibited marked acceleration in production of acid on non-fermentable carbon sources. Acid production is also dramatically enhanced by the superoxide-producing agent, paraquat. Conversely, the acid burst is eliminated by boosting cellular levels of Mn-antioxidant mimics of SOD. We demonstrate that the acid burst is dependent on the mitochondrial aldehyde dehydrogenase Ald4p. Our data are consistent with a model in which mitochondrial superoxide damage to Fe-S enzymes in the tricarboxylic acid (TCA) cycle leads to acetate buildup by Ald4p. The resultant expulsion of acetate into the extracellular environment can provide a new carbon source to glucose-starved cells and enhance growth of yeast. By triggering production of organic acids, mitochondrial superoxide has the potential to promote cell population growth under nutrient depravation stress. PMID:23281478

Superoxide reduction by a superoxide reductase lacking the highly conserved lysine residue

DOE PAGES

Teixeira, Miguel; Cabelli, Diane; Pinto, Ana F.; ...

2014-12-05

Superoxide reductases (SORs) are the most recently identified superoxide detoxification systems, being found in microorganisms from the three domains of life. These enzymes are characterized by a catalytic mononuclear iron site, with one cysteine and four histidine ligands of the ferrous active form. A lysine residue in the –EKHVP– motif, located close to the active site, has been considered to be essential for the enzyme function, by contributing to the positive surface patch that attracts the superoxide anion and by controlling the chemistry of the catalytic mechanism through a hydrogen bond network. However, we show here that this residue ismore » substituted by non-equivalent amino acids in several putative SORs from Archaea and unicellular Eukarya. In this work, we focus on mechanistic and spectroscopic studies of one of these less common enzymes, the SOR from the hyperthermophilic crenarchaeon Ignicoccus hospitalis. We employ pulse radiolysis fast kinetics and spectroscopic approaches to study the wild-type enzyme (₋E₂₃T₂₄HVP₋), and two mutants, T24K and E23A, the later mimicking enzymes lacking both the lysine and glutamate (a ferric ion ligand) of the motif. The efficiency of the wild type protein and mutants in reducing superoxide is comparable to other SORs, revealing the robustness of these enzymes to single mutations.« less

Caveolin-1 sensitizes cisplatin-induced lung cancer cell apoptosis via superoxide anion-dependent mechanism.

PubMed

Pongjit, Kanittha; Chanvorachote, Pithi

2011-12-01

Caveolin-1 (Cav-1) expression frequently found in lung cancer was linked with disease prognosis and progression. This study reveals for the first time that Cav-1 sensitizes cisplatin-induced lung carcinoma cell death by the mechanism involving oxidative stress modulation. We established stable Cav-1 overexpressed (H460/Cav-1) cells and investigated their cisplatin susceptibility in comparison with control-transfected cells and found that Cav-1 expression significantly enhanced cisplatin-mediated cell death. Results indicated that the different response to cisplatin between these cells was resulted from different level of superoxide anion induced by cisplatin. Inhibitory study revealed that superoxide anion inhibitor MnTBAP could inhibit cisplatin-mediated toxicity only in H460/Cav-1 cells while had no effect on H460 cells. Further, superoxide anion detected by DHE probe indicated that H460/Cav-1 cells generated significantly higher superoxide anion level in response to cisplatin than that of control cells. The role of Cav-1 in regulating cisplatin sensitivity was confirmed in shRNA-mediated Cav-1 down-regulated (H460/shCav-1) cells and the cells exhibited decreased cisplatin susceptibility and superoxide generation. In summary, these findings reveal novel aspects regarding role of Cav-1 in modulating oxidative stress induced by cisplatin, possibly providing new insights for cancer biology and cisplatin-based chemotherapy.

The ‘mitoflash’ probe cpYFP does not respond to superoxide

PubMed Central

Schwarzländer, Markus; Wagner, Stephan; Ermakova, Yulia G.; Belousov, Vsevolod V.; Radi, Rafael; Beckman, Joseph S.; Buettner, Garry R.; Demaurex, Nicolas; Duchen, Michael R.; Forman, Henry J.; Fricker, Mark D.; Gems, David; Halestrap, Andrew P.; Halliwell, Barry; Jakob, Ursula; Johnston, Iain G.; Jones, Nick S.; Logan, David C.; Morgan, Bruce; Müller, Florian L.; Nicholls, David G.; Remington, S. James; Schumacker, Paul T.; Winterbourn, Christine C.; Sweetlove, Lee J.; Meyer, Andreas J.; Dick, Tobias P.; Murphy, Michael P.

2015-01-01

Ageing and lifespan of organisms are determined by complicated interactions between their genetics and the environment, but the cellular mechanisms remain controversial. There have been a number of studies suggesting that cellular energy metabolism and free radical dynamics affect lifespan, implicating mitochondrial function. Recently, Shen et al.1 provided apparent mechanistic insight by reporting that mitochondrial oscillations of ‘free radical production’, called ‘mitoflashes’, in the pharynx of 3-day old Caenorhabditis elegans correlated inversely with lifespan. The interpretation of ‘mitoflashes’ as ‘bursts of superoxide’ radicals assumes that circularly permuted yellow fluorescent protein (cpYFP) is a reliable indicator of mitochondrial superoxide2. This interpretation has been criticised because experiments and theoretical considerations both show that changes in cpYFP fluorescence are due to alterations in pH, not superoxide3-7. We now provide direct evidence that purified cpYFP is completely unresponsive to superoxide. Therefore ‘mitoflashes’ do not reflect superoxide generation and are not evidence for a link between mitochondrial free radical dynamics and lifespan. PMID:25341790

Process for the preparation of calcium superoxide

NASA Technical Reports Server (NTRS)

Ballou, E. V.; Wood, P. C.; Wydeven, T. J.; Spitze, L. A. (Inventor)

1978-01-01

Calcium superoxide is prepared in high yields by spreading a quantity of calcium peroxide diperoxyhydrate on the surface of a container, positioning said container in a vacuum chamber on a support structure through which a coolant fluid can be circulated, partially evacuating said vacuum chamber, allowing the temperature of the diperoxyhydrate to reach the range of about 0 to about 40 C; maintaining the temperature selected for a period of time sufficient to complete the disproproriation of the diperoxyhydrate to calcium superoxide, calcium hydroxide, oxygen, and water; constantly and systematically removing the water as it is formed by sweeping the reacting material with a current of dry inert gas and/or by condensation of said water on a cold surface; backfilling the chamber with a dry inert gas; and finally, recovering the calcium superoxide produced.

Catalytic spectrofluorimetric determination of superoxide anion radical and superoxide dismutase activity using N, N-dimethylaniline as the substrate for horseradish peroxidase (HRP)

NASA Astrophysics Data System (ADS)

Tang, Bo; Wang, Yan; Chen, Zhen-zhen

2002-10-01

The coupled reaction of N, N-dimethylaniline (DMA) with 4-aminoantipyrine (4-AAP) using superoxide anion radical (O 2-) as oxidizing agent under the catalysis of horseradish peroxidase (HRP) was studied. Based on the reaction, O 2- produced by irradiating Vitamin B 2, (V B2) was spectrophotometricly determined at 554 nm. The linear range of this method was 1.8×10 -6-1.2×10 -4 mol l -1 with a detection limit of 5.3×10 -7 mol l -1. The effect of interferences on the determination of O 2- was investigated. The proposed method was successfully applied to the determination of superoxide dismutase (SOD) activity in human blood and mouse blood.

Concentration of extracellular superoxide radical as a function of time during lignin degradation by the fungus Coriolus versicolor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Amer, G.I.; Drew, S.W.

1981-01-01

During a 9 day fermentation of lignin by C. versicolor, the concentration of superoxide radical in the extracellular medium of the submerged culture rose and fell, reaching a maximum after 2 and 6 days of incubation, and a minimum at 3 and 8 days. The results indicate that the extracellular superoxide radical is involved in lignin degradation, but there was no evidence that it is an initial attacking agent. (Refs. 9).

Mitochondrial Complex IV Subunit 4 Isoform 2 Is Essential for Acute Pulmonary Oxygen Sensing.

PubMed

Sommer, Natascha; Hüttemann, Maik; Pak, Oleg; Scheibe, Susan; Knoepp, Fenja; Sinkler, Christopher; Malczyk, Monika; Gierhardt, Mareike; Esfandiary, Azadeh; Kraut, Simone; Jonas, Felix; Veith, Christine; Aras, Siddhesh; Sydykov, Akylbek; Alebrahimdehkordi, Nasim; Giehl, Klaudia; Hecker, Matthias; Brandes, Ralf P; Seeger, Werner; Grimminger, Friedrich; Ghofrani, Hossein A; Schermuly, Ralph T; Grossman, Lawrence I; Weissmann, Norbert

2017-08-04

Acute pulmonary oxygen sensing is essential to avoid life-threatening hypoxemia via hypoxic pulmonary vasoconstriction (HPV) which matches perfusion to ventilation. Hypoxia-induced mitochondrial superoxide release has been suggested as a critical step in the signaling pathway underlying HPV. However, the identity of the primary oxygen sensor and the mechanism of superoxide release in acute hypoxia, as well as its relevance for chronic pulmonary oxygen sensing, remain unresolved. To investigate the role of the pulmonary-specific isoform 2 of subunit 4 of the mitochondrial complex IV (Cox4i2) and the subsequent mediators superoxide and hydrogen peroxide for pulmonary oxygen sensing and signaling. Isolated ventilated and perfused lungs from Cox4i2 -/- mice lacked acute HPV. In parallel, pulmonary arterial smooth muscle cells (PASMCs) from Cox4i2 -/- mice showed no hypoxia-induced increase of intracellular calcium. Hypoxia-induced superoxide release which was detected by electron spin resonance spectroscopy in wild-type PASMCs was absent in Cox4i2 -/- PASMCs and was dependent on cysteine residues of Cox4i2. HPV could be inhibited by mitochondrial superoxide inhibitors proving the functional relevance of superoxide release for HPV. Mitochondrial hyperpolarization, which can promote mitochondrial superoxide release, was detected during acute hypoxia in wild-type but not Cox4i2 -/- PASMCs. Downstream signaling determined by patch-clamp measurements showed decreased hypoxia-induced cellular membrane depolarization in Cox4i2 -/- PASMCs compared with wild-type PASMCs, which could be normalized by the application of hydrogen peroxide. In contrast, chronic hypoxia-induced pulmonary hypertension and pulmonary vascular remodeling were not or only slightly affected by Cox4i2 deficiency, respectively. Cox4i2 is essential for acute but not chronic pulmonary oxygen sensing by triggering mitochondrial hyperpolarization and release of mitochondrial superoxide which, after conversion to hydrogen peroxide, contributes to cellular membrane depolarization and HPV. These findings provide a new model for oxygen-sensing processes in the lung and possibly also in other organs. © 2017 American Heart Association, Inc.

Optical studies of oxidative stress in pulmonary artery endothelial cells

NASA Astrophysics Data System (ADS)

Ghanian, Zahra; Sepehr, Reyhaneh; Eis, Annie; Kondouri, Ganesh; Ranji, Mahsa

2015-03-01

Reactive oxygen species (ROS) play an essential role in facilitating signal transduction processes within the cell and modulating the injuries. However, the generation of ROS is tightly controlled both spatially and temporally within the cell, making the study of ROS dynamics particularly difficult. This study present a novel protocol to quantify the dynamic of the mitochondrial superoxide as a precursor of reactive oxygen species. To regulate the mitochondrial superoxide level, metabolic perturbation was induced by administration of potassium cyanide (KCN). The presented method was able to monitor and measure the superoxide production rate over time. Our results demonstrated that the metabolic inhibitor, potassium cyanide (KCN) induced a significant increase in the rate of superoxide production in mitochondria of fetal pulmonary artery endothelial cells (FPAEC). Presented method sets the stage to study different ROS mediated injuries in vitro.

[Involvement of carbonate/bicarbonate ions in the superoxide-generating reaction of adrenaline autoxidation].

PubMed

Sirota, T V

2015-01-01

An important role of carbonate/bicarbonate ions has been recognized in the superoxide generating reaction of adrenaline autooxidation in an alkaline buffer (a model of quinoid adrenaline oxidation in the body). It is suggested that these ions are directly involved not only in formation of superoxide anion radical (О(2)(-)) but also other radicals derived from the carbonate/bicarbonate buffer. Using various buffers it was shown that the rate of accumulation of adrenochrome, the end product of adrenaline oxidation, and the rate of О(2)(-)· formation depend on concentration of carbonate/bicarbonate ions in the buffer and that these ions significantly accelerate adrenaline autooxidation thus demonstrating prooxidant properties. The detectable amount of diformazan, the product of nitro blue tetrazolium (NBT) reduction, was significantly higher than the amount of adrenochrome formed; taking into consideration the literature data on О(2)(-)· detection by NBT it is suggested that adrenaline autooxidation is accompanied by one-electron reduction not only of oxygen dissolved in the buffer and responsible for superoxide formation but possible carbon dioxide also dissolved in the buffer as well as carbonate/bicarbonate buffer components leading to formation of corresponding radicals. The plots of the dependence of the inhibition of adrenochrome and diformazan formation on the superoxide dismutase concentration have shown that not only superoxide radicals are formed during adrenaline autooxidation. Since carbonate/bicarbonate ions are known to be universally present in the living nature, their involvement in free radical processes proceeding in the organism is discussed.

Diosgenin inhibits superoxide generation in FMLP-activated mouse neutrophils via multiple pathways.

PubMed

Lin, Y; Jia, R; Liu, Y; Gao, Y; Zeng, X; Kou, J; Yu, B

2014-12-01

Diosgenin possesses anti-inflammatory and anticancer properties. Activated neutrophils produce high concentrations of the superoxide anion which is involved in the pathophysiology of inflammation-related diseases and cancer. In the present study, the inhibitory effect and possible mechanisms of diosgenin on superoxide generation were investigated in mouse bone marrow neutrophils. Diosgenin potently and concentration-dependently inhibited the extracellular and intracellular superoxide anion generation in Formyl-Met-Leu-Phe (FMLP)- activated neutrophils, with IC50 values of 0.50 ± 0.08 μM and 0.66 ± 0.13 μM, respectively. Such inhibition was not mediated by scavenging the superoxide anion or by a cytotoxic effect. Diosgenin inhibited the phosphorylation of p47phox and membrane translocation of p47phox and p67phox, and thus blocking the assembly of nicotinamide adenine dinucleotide phosphate oxidase. Moreover, cellular cyclic adenosine monophosphate (cAMP) levels and protein kinase A (PKA) expression were also effectively increased by diosgenin. It attenuated FMLP-induced increase of phosphorylation of cytosolic phospholipase A (cPLA2), p21-activated kinase (PAK), Akt, p38 mitogen-activated protein kinase (p38MAPK), extracellular signal-regulated kinase (ERK1/2), and c-Jun N-terminal kinase (JNK). Our data indicate that diosgenin exhibits inhibitory effects on superoxide anion production through the blockade of cAMP, PKA, cPLA2, PAK, Akt and MAPKs signaling pathways. The results may explain the clinical implications of diosgenin in the treatment of inflammation-related disorders.

Size and targeting to PECAM vs ICAM control endothelial delivery, internalization and protective effect of multimolecular SOD conjugates.

PubMed

Shuvaev, Vladimir V; Muro, Silvia; Arguiri, Evguenia; Khoshnejad, Makan; Tliba, Samira; Christofidou-Solomidou, Melpo; Muzykantov, Vladimir R

2016-07-28

Controlled endothelial delivery of SOD may alleviate abnormal local surplus of superoxide involved in ischemia-reperfusion, inflammation and other disease conditions. Targeting SOD to endothelial surface vs. intracellular compartments is desirable to prevent pathological effects of external vs. endogenous superoxide, respectively. Thus, SOD conjugated with antibodies to cell adhesion molecule PECAM (Ab/SOD) inhibits pro-inflammatory signaling mediated by endogenous superoxide produced in the endothelial endosomes in response to cytokines. Here we defined control of surface vs. endosomal delivery and effect of Ab/SOD, focusing on conjugate size and targeting to PECAM vs. ICAM. Ab/SOD enlargement from about 100 to 300nm enhanced amount of cell-bound SOD and protection against extracellular superoxide. In contrast, enlargement inhibited endocytosis of Ab/SOD and diminished mitigation of inflammatory signaling of endothelial superoxide. In addition to size, shape is important: endocytosis of antibody-coated spheres was more effective than that of polymorphous antibody conjugates. Further, targeting to ICAM provides higher endocytic efficacy than targeting to PECAM. ICAM-targeted Ab/SOD more effectively mitigated inflammatory signaling by intracellular superoxide in vitro and in animal models, although total uptake was inferior to that of PECAM-targeted Ab/SOD. Therefore, both geometry and targeting features of Ab/SOD conjugates control delivery to cell surface vs. endosomes for optimal protection against extracellular vs. endosomal oxidative stress, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

Antioxidant potential of selected Spirulina platensis preparations.

PubMed

Dartsch, Peter C

2008-05-01

Recent studies suggest that Spirulina, a unicellular blue-green alga, may have a variety of health benefits and therapeutic properties and is also capable of acting as an antioxidant and antiinflammatory agent. In this study, a cell-free and a cell-based test assay were used to examine the antioxidant and antiinflammatory properties of four selected Spirulina platensis preparations: (1) Biospirulina, (2) SpiruComplex, a preparation with naturally bound selenium, chromium and zinc, (3) SpiruZink, a preparation with naturally bound zinc, (4) Zinkspirulina + Acerola, a preparation with naturally bound zinc and acerola powder. The cell-free test assay used potassium superoxide as a donor for superoxide radicals, whereas the cell-based test assay used the formation of intracellular superoxide radicals of functional neutrophils upon stimulation by phorbol-12-myristate-13-acetate as a model to investigate the potential of Spirulina preparations to inactivate superoxide radicals. In accordance with the recommended daily dosage, test concentrations ranging from 50 to 1000 microg/mL were chosen. The results showed a dose-dependent inactivation of free superoxide radicals (antioxidant effect) as well as an antiinflammatory effect characterized by a dose-dependent reduction of the metabolic activity of functional neutrophils and a dose-dependent inactivation of superoxide radicals generated during an oxidative burst. The results demonstrate that the tested Spirulina preparations have a high antioxidant and antiinflammatory potential. Especially SpiruZink and Zinkspirulina + Acerola might be useful as a supportive therapeutic approach for reducing oxidative stress and/or the generation of oxygen radicals in the course of inflammatory processes.

Co(II) derivatives of Cu,Zn-superoxide dismutase with the cobalt bound in the place of copper. A new spectroscopic tool for the study of the active site.

PubMed

Desideri, A; Cocco, D; Calabrese, L; Rotilio, G

1984-03-29

Co(II) derivatives of Cu,Zn-superoxide dismutase having cobalt substituted for the copper (Co,Zn-superoxide dismutase and Co,Co-superoxide dismutase) were studied by optical and EPR spectroscopy. EPR and electronic absorption spectra of Co,Zn-superoxide dismutase are sensitive to solvent perturbation, and in particular to the presence of phosphate. This behaviour suggests that cobalt in Co,Zn-superoxide dismutase is open to solvent access, at variance with the Co(II) of the Cu,Co-superoxide dismutase, which is substituted for the Zn. Phosphate binding as monitored by optical titration is dependent on pH with an apparent pKa = 8.2. The absorption spectrum of Co,Zn-superoxide dismutase in water has three weak bands in the visible region (epsilon = 75 M-1 X cm-1 at 456 nm; epsilon = 90 M-1 X cm-1 at 520 nm; epsilon = 70 M-1 X cm-1 at 600 nm) and three bands in the near infrared region, at 790 nm (epsilon = 18 M-1 X cm-1), 916 nm (epsilon = 27 M-1 X cm-1) and 1045 nm (epsilon = 25 M-1 X cm-1). This spectrum is indicative of five-coordinate geometry. In the presence of phosphate, three bands are still present in the visible region but they have higher intensity (epsilon = 225 M-1 X cm-1 at 544 nm; epsilon = 315 M-1 X cm-1 at 575 nm; epsilon = 330 M-1 X cm-1 at 603 nm), whilst the lowest wavelength band in the near infrared region is at much lower energy, 1060 nm (epsilon = 44 M-1 X cm-1). The latter property suggests a tetrahedral coordination around the Co(II) centre. Addition of 1 equivalent of CN- gives rise to a stable Co(II) low-spin intermediate, which is characterized by an EPR spectrum with a highly rhombic line shape. Formation of this CN- complex was found to require more cyanide equivalents in the case of the phosphate adduct, suggesting that binding of phosphate may inhibit binding of other anions. Titration of the Co,Co-derivative with CN- provided evidence for magnetic interaction between the two metal centres. These results substantiate the contention that Co(II) can replace the copper of Cu,Zn-superoxide dismutase in a way that reproduces the properties of the native copper-binding site.

Suppressors of Superoxide-H2O2 Production at Site IQ of Mitochondrial Complex I Protect against Stem Cell Hyperplasia and Ischemia-Reperfusion Injury.

PubMed

Brand, Martin D; Goncalves, Renata L S; Orr, Adam L; Vargas, Leonardo; Gerencser, Akos A; Borch Jensen, Martin; Wang, Yves T; Melov, Simon; Turk, Carolina N; Matzen, Jason T; Dardov, Victoria J; Petrassi, H Michael; Meeusen, Shelly L; Perevoshchikova, Irina V; Jasper, Heinrich; Brookes, Paul S; Ainscow, Edward K

2016-10-11

Using high-throughput screening we identified small molecules that suppress superoxide and/or H 2 O 2 production during reverse electron transport through mitochondrial respiratory complex I (site I Q ) without affecting oxidative phosphorylation (suppressors of site I Q electron leak, "S1QELs"). S1QELs diminished endogenous oxidative damage in primary astrocytes cultured at ambient or low oxygen tension, showing that site I Q is a normal contributor to mitochondrial superoxide-H 2 O 2 production in cells. They diminished stem cell hyperplasia in Drosophila intestine in vivo and caspase activation in a cardiomyocyte cell model driven by endoplasmic reticulum stress, showing that superoxide-H 2 O 2 production by site I Q  is involved in cellular stress signaling. They protected against ischemia-reperfusion injury in perfused mouse heart, showing directly that superoxide-H 2 O 2 production by site I Q is a major contributor to this pathology. S1QELs are tools for assessing the contribution of site I Q to cell physiology and pathology and have great potential as therapeutic leads. Copyright © 2016 Elsevier Inc. All rights reserved.

Effects of five oleanolic acid triterpenoid saponins from the rhizome of Anemone raddeana on stimulus-induced superoxide generation, phosphorylation of proteins and translocation of cytosolic compounds to cell membrane in human neutrophils.

PubMed

Wei, Shihu; He, Wenfei; Lu, Jincai; Wang, Zhonghuan; Yamashita, Koichi; Yokoyama, Masanori; Kodama, Hiroyuki

2012-03-01

Five oleanolic acid triterpenoid saponins (OTS-1, 2, 3, 4 and 5) were isolated from the rhizome of Anemone raddeana. The effect of these triterpenoid saponins on stimulus-induced superoxide generation in human neutrophils was assayed by measuring the reduction of ferricytochrome c using a dual-beam spectrophotometer. The phosphorylation of neutrophil proteins, and translocation of p67(phox), p47(phox) and Rac to plasma membrane were investigated using specific monoclonal antibodies. The five oleanolic acid triterpenoid saponins used in this experiment suppressed N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced superoxide generation in a concentration-dependent manner. OTS-1, 2 and 4 suppressed phorbol 12-myristate 13-acetate (PMA)- and arachidonic acid (AA)-induced superoxide generation in a concentration-dependent manner, but OTS-3 and 5 showed no effect. fMLP- and PMA-induced tyrosyl or serine/threonine phosphorylation, and fMLP-, PMA- and AA-induced translocation of p67(phox), p47(phox) and Rac to plasma membrane were in parallel with the suppression of the stimulus-induced superoxide generation. Copyright © 2011 Elsevier B.V. All rights reserved.

Involvement of Superoxide Dismutases in the Response of Escherichia coli to Selenium Oxides

PubMed Central

Bébien, Magali; Lagniel, Gilles; Garin, Jérôme; Touati, Danièle; Verméglio, André; Labarre, Jean

2002-01-01

Selenium can provoke contrasting effects on living organisms. It is an essential trace element, and low concentrations have beneficial effects, such as the reduction of the incidence of cancer. However, higher concentrations of selenium salts can be toxic and mutagenic. The bases for both toxicity and protection are not clearly understood. To provide insights into these mechanisms, we analyzed the proteomic response of Escherichia coli cells to selenate and selenite treatment under aerobic conditions. We identified 23 proteins induced by both oxides and ca. 20 proteins specifically induced by each oxide. A striking result was the selenite induction of 8 enzymes with antioxidant properties, particularly the manganese and iron superoxide dismutases (SodA and SodB). The selenium inductions of sodA and sodB were controlled by the transcriptional regulators SoxRS and Fur, respectively. Strains with decreased superoxide dismutase activities were severely impaired in selenium oxide tolerance. Pretreatment with a sublethal selenite concentration triggered an adaptive response dependent upon SoxRS, conferring increased selenite tolerance. Altogether, our data indicate that superoxide dismutase activity is essential for the cellular defense against selenium salts, suggesting that superoxide production is a major mechanism of selenium toxicity under aerobic conditions. PMID:11872706

Mitochondrial flashes: From indicator characterization to in vivo imaging.

PubMed

Wang, Wang; Zhang, Huiliang; Cheng, Heping

2016-10-15

Mitochondrion is an organelle critically responsible for energy production and intracellular signaling in eukaryotic cells and its dysfunction often accompanies and contributes to human disease. Superoxide is the primary reactive oxygen species (ROS) produced in mitochondria. In vivo detection of superoxide has been a challenge in biomedical research. Here we describe the methods used to characterize a circularly permuted yellow fluorescent protein (cpYFP) as a biosensor for mitochondrial superoxide and pH dynamics. In vitro characterization reveals the high selectivity of cpYFP to superoxide over other ROS species and its dual sensitivity to pH. Confocal and two-photon imaging in conjunction with transgenic expression of the biosensor cpYFP targeted to the mitochondrial matrix detects mitochondrial flash events in living cells, perfused intact hearts, and live animals. The mitochondrial flashes are discrete and stochastic single mitochondrial events triggered by transient mitochondrial permeability transition (tMPT) and composed of a bursting superoxide signal and a transient alkalization signal. The real-time monitoring of single mitochondrial flashes provides a unique tool to study the integrated dynamism of mitochondrial respiration, ROS production, pH regulation and tMPT kinetics under diverse physiological and pathophysiological conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

Metal ions induced heat shock protein response by elevating superoxide anion level in HeLa cells transformed by HSE-SEAP reporter gene.

PubMed

Yu, Zhanjiang; Yang, Xiaoda; Wang, Kui

2006-06-01

The aim of this work is to define the relationship between heat shock protein (HSP) and reactive oxygen species (ROS) in the cells exposed to different concentrations of metal ions, and to evaluate a new method for tracing the dynamic levels of cellular reactive oxygen species using a HSE-SEAP reporter gene. The expression of heat shock protein was measured using a secreted alkaline phosphatase (SEAP) reporter gene transformed into HeLa cell strain, the levels of superoxide anion (O(2)(-)) and hydrogen peroxide (H(2)O(2)) were determined by NBT reduction assay and DCFH staining flow cytometry (FCM), respectively. The experimental results demonstrated that the expression of heat shock protein induced by metal ions was linearly related to the cellular superoxide anion level before cytotoxic effects were observed, but not related to the cellular hydrogen peroxide level. The experimental results suggested that metal ions might induce heat shock protein by elevating cellular superoxide anion level, and thus the expression of heat shock protein indicated by the HSE-SEAP reporter gene can be an effective model for monitoring the dynamic level of superoxide anion and early metal-induced oxidative stress/cytotoxicity.

Extraction of erythrocyte enzymes for the preparation of polyhemoglobin-catalase-superoxide dismutase.

PubMed

Gu, Jingsong; Chang, Thomas Ming Swi

2009-01-01

In sustained severe ischemia, reperfusion with oxygen carriers may result in ischemia-reperfusion injuries because of the release of damaging oxygen radicals. A nanobiotechnology-based polyhemogloin-calatase-superoxide dismutase can prevent this because the oxygen carrier, polyhemoglobin, is linked to antioxidant enzymes, catalase and superoxide dismutase. However, these antioxidant enzymes come from nonhuman sources and recombinant human enzymes are expensive. This paper describes our study on extracting these enzymes from red blood cells and analyzing the amount of enzymes needed for adequate protection from ischemia-reperfusion.

The Single Superoxide Dismutase of Rhodobacter capsulatus Is a Cambialistic, Manganese-Containing Enzyme

PubMed Central

Tabares, Leandro C.; Bittel, Cristian; Carrillo, Néstor; Bortolotti, Ana; Cortez, Néstor

2003-01-01

The phototrophic bacterium Rhodobacter capsulatus contains a single, oxygen-responsive superoxide dismutase (SODRc) homologous to iron-containing superoxide dismutase enzymes. Recombinant SODRc, however, displayed higher activity after refolding with Mn2+, especially when the pH of the assay mixture was raised. SODRc isolated from Rhodobacter cells also preferentially contains manganese, but metal discrimination depends on the culture conditions, with iron fractions increasing from 7% in aerobic cultures up to 40% in photosynthetic cultures. Therefore, SODRc behaves as a Mn-containing dismutase with cambialistic properties. PMID:12730184

Nitric oxide alterations following acute ductal constriction in the fetal lamb: a role for superoxide

PubMed Central

Hsu, Jong-Hau; Oishi, Peter; Wiseman, Dean A.; Hou, Yali; Chikovani, Omar; Datar, Sanjeev; Sajti, Eniko; Johengen, Michael J.; Harmon, Cynthia; Black, Stephen M.

2010-01-01

Acute partial compression of the fetal ductus arteriosus (DA) results in an initial abrupt increase in pulmonary blood flow (PBF), which is followed by a significant reduction in PBF to baseline values over the ensuing 2–4 h. We have previously demonstrated that this potent vasoconstricting response is due, in part, to an endothelin-1 (ET-1)-mediated decrease in nitric oxide synthase (NOS) activity. In addition, in vitro data demonstrate that ET-1 increases superoxide levels in pulmonary arterial smooth muscle cells and that oxidative stress alters NOS activity. Therefore, the objectives of this study were to determine the potential role of superoxide in the alterations of hemodynamics and NOS activity following acute ductal constriction in the late-gestation fetal lamb. Eighteen anesthetized near-term fetal lambs were instrumented, and a lung biopsy was performed. After a 48-h recovery, acute constriction of the DA was performed by inflating a vascular occluder. Polyethylene glycol-superoxide dismutase (PEG-SOD; 1,000–1,500 units/kg, n = 7) or PEG-alone (vehicle control group, n = 5) was injected into the pulmonary artery before ductal constriction. Six animals had a sham operation. In PEG-alone-treated lambs, acute ductal constriction rapidly decreased pulmonary vascular resistance (PVR) by 88%. However, by 4 h, PVR returned to preconstriction baseline. This vasoconstriction was associated with an increase in lung superoxide levels (82%), a decrease in total NOS activity (50%), and an increase in P-eNOS-Thr495 (52%) (P < 0.05). PEG-SOD prevented the increase of superoxide after ductal constriction, attenuated the vasoconstriction, preserved NOS activity, and increased P-eNOS Ser1177 (307%, P < 0.05). Sham procedure induced no changes. These data suggest that an acute decrease in NOS activity that is mediated, in part, by increased superoxide levels, and alterations in the phosphorylation status of the endothelial NOS isoform, underlie the pulmonary vascular response to acute ductal constriction. PMID:20363848

Role of superoxide–nitric oxide interactions in the accelerated age-related loss of muscle mass in mice lacking Cu,Zn superoxide dismutase

PubMed Central

Sakellariou, Giorgos K; Pye, Deborah; Vasilaki, Aphrodite; Zibrik, Lea; Palomero, Jesus; Kabayo, Tabitha; McArdle, Francis; Van Remmen, Holly; Richardson, Arlan; Tidball, James G; McArdle, Anne; Jackson, Malcolm J

2011-01-01

Summary Mice lacking Cu,Zn superoxide dismutase (SOD1) show accelerated, age-related loss of muscle mass. Lack of SOD1 may lead to increased superoxide, reduced nitric oxide (NO), and increased peroxynitrite, each of which could initiate muscle fiber loss. Single muscle fibers from flexor digitorum brevis of wild-type (WT) and Sod1−/− mice were loaded with NO-sensitive (4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate, DAF-FM) and superoxide-sensitive (dihydroethidium, DHE) probes. Gastrocnemius muscles were analyzed for SOD enzymes, nitric oxide synthases (NOS), and 3-nitrotyrosine (3-NT) content. A lack of SOD1 did not increase superoxide availability at rest because no increase in ethidium or 2-hydroxyethidium (2-HE) formation from DHE was seen in fibers from Sod1−/− mice compared with those from WT mice. Fibers from Sod1−/− mice had decreased NO availability (decreased DAF-FM fluorescence), increased 3-NT in muscle proteins indicating increased peroxynitrite formation and increased content of peroxiredoxin V (a peroxynitrite reductase), compared with WT mice. Muscle fibers from Sod1−/− mice showed substantially reduced generation of superoxide in response to contractions compared with fibers from WT mice. Inhibition of NOS did not affect DHE oxidation in fibers from WT or Sod1−/− mice at rest or during contractions, but transgenic mice overexpressing nNOS showed increased DAF-FM fluorescence and reduced DHE oxidation in resting muscle fibers. It is concluded that formation of peroxynitrite in muscle fibers is a major effect of lack of SOD1 in Sod1−/− mice and may contribute to fiber loss in this model, and that NO regulates superoxide availability and peroxynitrite formation in muscle. PMID:21443684

Ceramide does not mediate the effect of tumour necrosis factor alpha on superoxide generation in human neutrophils.

PubMed Central

Yanaga, F; Watson, S P

1994-01-01

The effect of tumour necrosis factor alpha (TNF alpha) on superoxide generation in human neutrophils was investigated using the Nitro Blue Tetrazolium reduction assay. TNF alpha stimulated superoxide generation in a time- and concentration-dependent fashion. The maximally effective concentration of TNF alpha for superoxide generation was 10 nM and maximal response was obtained after 15-20 min. The monoclonal antibody (mAb), utr-1, which was raised against the 75 kDa receptor and behaves as an antagonist, had no effect on superoxide generation, but partially inhibited the response to TNF alpha. mAb htr-9, which was raised against the 55 kDa receptor and behaves as an agonist, mimicked the effect of TNF alpha, but with a lower maximal response. As it has been reported that ceramide might act as a second messenger to mediate many of the effects of TNF alpha, the effects of exogenous sphingomyelinase and the cell-permeable ceramide analogue, C2- ceramide, on production of superoxide anions, induction of priming in response to formylmethionyl-leucyl-phenylalanine, and cell-shape change were examined. Neither sphingomyelinase nor C2-ceramide mimicked the effect of TNF alpha. Ceramide is converted into ceramide 1-phosphate by ceramide kinase and we have measured levels of this metabolite to clarify the effect of TNF alpha on sphingomyelinase activity in neutrophils. Although exogenous sphingomyelinase increased the amount of ceramide 1-phosphate in a time-dependent manner, and C2-ceramide was rapidly converted into C2-ceramide phosphate, TNF alpha had no effect on the level of ceramide 1-phosphate. These results suggest that TNF alpha stimulates superoxide generation through both the 55 kDa and 75 kDa receptors, but that ceramide does not act as an intracellular mediator for TNF alpha in human neutrophils. Images Figure 4 PMID:8141790

Constraints on superoxide mediated formation of manganese oxides

PubMed Central

Learman, Deric R.; Voelker, Bettina M.; Madden, Andrew S.; Hansel, Colleen M.

2013-01-01

Manganese (Mn) oxides are among the most reactive sorbents and oxidants within the environment, where they play a central role in the cycling of nutrients, metals, and carbon. Recent discoveries have identified superoxide (O2−) both of biogenic and abiogenic origin as an effective oxidant of Mn(II) leading to the formation of Mn oxides. Here we examined the conditions under which abiotically produced superoxide led to oxidative precipitation of Mn and the solid-phases produced. Oxidized Mn, as both aqueous Mn(III) and Mn(III/IV) oxides, was only observed in the presence of active catalase, indicating that hydrogen peroxide (H2O2), a product of the reaction of O2− with Mn(II), inhibits the oxidation process presumably through the reduction of Mn(III). Citrate and pyrophosphate increased the yield of oxidized Mn but decreased the amount of Mn oxide produced via formation of Mn(III)-ligand complexes. While complexing ligands played a role in stabilizing Mn(III), they did not eliminate the inhibition of net Mn(III) formation by H2O2. The Mn oxides precipitated were highly disordered colloidal hexagonal birnessite, similar to those produced by biotically generated superoxide. Yet, in contrast to the large particulate Mn oxides formed by biogenic superoxide, abiotic Mn oxides did not ripen to larger, more crystalline phases. This suggests that the deposition of crystalline Mn oxides within the environment requires a biological, or at least organic, influence. This work provides the first direct evidence that, under conditions relevant to natural waters, oxidation of Mn(II) by superoxide can occur and lead to formation of Mn oxides. For organisms that oxidize Mn(II) by producing superoxide, these findings may also point to other microbially mediated processes, in particular enzymatic hydrogen peroxide degradation and/or production of organic ligand metabolites, that allow for Mn oxide formation. PMID:24027565

HV1 acts as a sodium sensor and promotes superoxide production in medullary thick ascending limb of Dahl salt-sensitive rats.

PubMed

Jin, Chunhua; Sun, Jingping; Stilphen, Carly A; Smith, Susan M E; Ocasio, Hiram; Bermingham, Brent; Darji, Sandip; Guha, Avirup; Patel, Roshan; Geurts, Aron M; Jacob, Howard J; Lambert, Nevin A; O'Connor, Paul M

2014-09-01

We previously characterized a H(+) transport pathway in medullary thick ascending limb nephron segments that when activated stimulated the production of superoxide by nicotinamide adenine dinucleotide phosphate oxidase. Importantly, the activity of this pathway was greater in Dahl salt-sensitive rats than salt-resistant (SS.13(BN)) rats, and superoxide production was enhanced in low Na(+) media. The goal of this study was to determine the molecular identity of this pathway and its relationship to Na(+). We hypothesized that the voltage-gated proton channel, HV1, was the source of superoxide-stimulating H(+) currents. To test this hypothesis, we developed HV1(-/-) null mutant rats on the Dahl salt-sensitive rat genetic background using zinc-finger nuclease gene targeting. HV1 could be detected in medullary thick limb from wild-type rats. Intracellular acidification using an NH4Cl prepulse in 0 sodium/BaCl2 containing media resulted in superoxide production in thick limb from wild-type but not HV1(-/-) rats (P<0.05) and more rapid recovery of intracellular pH in wild-type rats (ΔpHI 0.005 versus 0.002 U/s, P=0.046, respectively). Superoxide production was enhanced by low intracellular sodium (<10 mmol/L) in both thick limb and peritoneal macrophages only when HV1 was present. When fed a high-salt diet, blood pressure, outer medullary renal injury (tubular casts), and oxidative stress (4-hydroxynonenal staining) were significantly reduced in HV1(-/-) rats compared with wild-type Dahl salt-sensitive rats. We conclude that HV1 is expressed in medullary thick ascending limb and promotes superoxide production in this segment when intracellular Na(+) is low. HV1 contributes to the development of hypertension and renal disease in Dahl salt-sensitive rats. © 2014 American Heart Association, Inc.

Mitochondrial generation of superoxide and hydrogen peroxide as the source of mitochondrial redox signaling.

PubMed

Brand, Martin D

2016-11-01

This review examines the generation of reactive oxygen species by mammalian mitochondria, and the status of different sites of production in redox signaling and pathology. Eleven distinct mitochondrial sites associated with substrate oxidation and oxidative phosphorylation leak electrons to oxygen to produce superoxide or hydrogen peroxide: oxoacid dehydrogenase complexes that feed electrons to NAD + ; respiratory complexes I and III, and dehydrogenases, including complex II, that use ubiquinone as acceptor. The topologies, capacities, and substrate dependences of each site have recently clarified. Complex III and mitochondrial glycerol 3-phosphate dehydrogenase generate superoxide to the external side of the mitochondrial inner membrane as well as the matrix, the other sites generate superoxide and/or hydrogen peroxide exclusively in the matrix. These different site-specific topologies are important for redox signaling. The net rate of superoxide or hydrogen peroxide generation depends on the substrates present and the antioxidant systems active in the matrix and cytosol. The rate at each site can now be measured in complex substrate mixtures. In skeletal muscle mitochondria in media mimicking muscle cytosol at rest, four sites dominate, two in complex I and one each in complexes II and III. Specific suppressors of two sites have been identified, the outer ubiquinone-binding site in complex III (site III Qo ) and the site in complex I active during reverse electron transport (site I Q ). These suppressors prevent superoxide/hydrogen peroxide production from a specific site without affecting oxidative phosphorylation, making them excellent tools to investigate the status of the sites in redox signaling, and to suppress the sites to prevent pathologies. They allow the cellular roles of mitochondrial superoxide/hydrogen peroxide production to be investigated without catastrophic confounding bioenergetic effects. They show that sites III Qo and I Q are active in cells and have important roles in redox signaling (e.g. hypoxic signaling and ER-stress) and in causing oxidative damage in a variety of biological contexts. Copyright © 2016 Elsevier Inc. All rights reserved.

Antiperoxidation activity of triterpenoids from rhizome of Anemone raddeana.

PubMed

Chen, Xin; Lu, Jincai; He, Wenfei; Chi, Haidong; Yamashita, Koichi; Manabe, Masanobu; Kodama, Hiroyuki

2009-03-01

Four triterpenoid compounds hederacolchiside E (1), hederasaponin B (2), raddeanoside 20 (3) and raddeanoside 21 (4) were isolated from ethanol extracts of rhizome of Anemone raddeana Regel. The effects of these triterpenoids on superoxide generation, tyrosyl phosphorylation of proteins and translocation of cytosolic compounds, such as p47(phox), p67(phox) and Rac to the cell membrane in human neutrophils was investigated. The superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine (fMLP) was slightly suppressed by hederasaponin B, raddeanoside 20 and raddeanoside 21 in a concentration dependent manner. The superoxide generation induced by arachidonic acid (AA) was suppressed by hederasaponin B and raddeanoside 21 significantly. fMLP- and AA-induced tyrosyl phosphorylation and translocation of the cytosolic proteins: p47(phox), p67(phox), and Rac to the cell membrane were suppressed in parallel with the suppression of stimulus-induced superoxide generation.

Copper, Zinc Superoxide Dismutase is Primarily a Cytosolic Protein in Human Cells

NASA Astrophysics Data System (ADS)

Crapo, James D.; Oury, Tim; Rabouille, Catherine; Slot, Jan W.; Chang, Ling-Yi

1992-11-01

The intracellular localization of human copper, zinc superoxide dismutase (Cu,Zn-SOD; superoxide:superoxide oxidoreductase, EC 1.15.1.1) was evaluated by using EM immunocytochemistry and both isolated human cell lines and human tissues. Eight monoclonal antibodies raised against either native or recombinant human Cu,Zn-SOD and two polyclonal antibodies raised against either native or recombinant human Cu,Zn-SOD were used. Fixation with 2% paraformaldehyde/0.2% glutaraldehyde was found necessary to preserve normal distribution of the protein. Monoclonal antibodies were less effective than polyclonal antibodies in recognizing the antigen after adequate fixation of tissue. Cu,Zn-SOD was found widely distributed in the cell cytosol and in the cell nucleus, consistent with it being a soluble cytosolic protein. Mitochondria and secretory compartments did not label for this protein. In human cells, peroxisomes showed a labeling density slightly less than that of cytoplasm.

Predictors of telomere content in dragon lizards

NASA Astrophysics Data System (ADS)

Ballen, Cissy; Healey, Mo; Wilson, Mark; Tobler, Michael; Olsson, Mats

2012-08-01

Telomeres shorten as a consequence of DNA replication, in particular in cells with low production of telomerase and perhaps in response to physiological stress from exposure to reactive oxygen species, such as superoxide. This process of telomere attrition is countered by innate antioxidation, such as via the production of superoxide dismutase. We studied the inheritance of telomere length in the Australian painted dragon lizard ( Ctenophorus pictus) and the extent to which telomere length covaries with mass-corrected maternal reproductive investment, which reflects the level of circulating yolk precursor and antioxidant, vitellogenin. Our predictors of offspring telomere length explained 72 % of telomere variation (including interstitial telomeres if such are present). Maternal telomere length and reproductive investment were positively influencing offspring telomere length in our analyses, whereas flow cytometry-estimated superoxide level was negatively impacting offspring telomere length. We suggest that the effects of superoxide on hatchling telomere shortening may be partly balanced by transgenerational effects of vitellogenin antioxidation.

Antioxidant properties of nicergoline; inhibition of brain auto-oxidation and superoxide production of neutrophils in rats.

PubMed

Tanaka, M; Yoshida, T; Okamoto, K; Hirai, S

1998-05-22

Oxidative stress has been suggested to adversely influence cerebrovascular disorders and some neurodegenerative disorders. We examined whether nicergoline, an agent widely used for treating cerebrovascular disorders and senile mental impairment, possesses antioxidant activities and some beneficial effect on neutrophils generating free radicals. Although nicergoline did not scavenge superoxide produced from a superoxide-generating system, it significantly inhibited superoxide secretion from stimulated neutrophils. Auto-oxidation of brain homogenate of rats, monitored by formation of thiobarbituric acid-reactive substances, was suppressed by nicergoline in a dose-dependent manner. The oxidation of the homogenate was accelerated by activated neutrophils and was significantly suppressed by nicergoline. These observations suggest that nicergoine is an antioxidant that inhibits not only lipid peroxidation but also free radical generation from neutrophils. These properties of nicergoline should be beneficial in some pathological conditions including cerebrovascular and neurodegenerative disorders in which oxidative stress may have a pathoetiological role.

SK-N-MC cell death occurs by distinct molecular mechanisms in response to hydrogen peroxide and superoxide anions: involvements of JAK2-STAT3, JNK, and p38 MAP kinases pathways.

PubMed

Moslehi, Maryam; Yazdanparast, Razieh

2013-07-01

Oxidative stress plays a vital role in the pathogenesis of neurodegenerative diseases. Nerve cells are incessantly exposed to environmental stresses leading to overproduction of some harmful species like reactive oxygen species (ROS). ROS including hydrogen peroxide and superoxide anion are potent inducers of various signaling pathways encompassing MAPKs and JAK-STAT pathways. In the current study, we scrutinized the effects of hydrogen peroxide and/or menadione (superoxide anion generator) on JNK/p38-MAPKs and JAK2-STAT3 pathways to elucidate the mechanism(s) by which each oxidant modulated the above-mentioned pathways leading to SK-N-MC cell death. Our results delineated that hydrogen peroxide and superoxide anion radical induced distinct responses as we showed that STAT3 and p38 were activated in response to hydrogen peroxide, but not superoxide anion radicals indicating the specificity in ROS-induced signaling pathways activations and behaviors. We also observed that menadione induced JNK-dependent p53 expression and apoptotic death in SK-N-MC cells while H2O2-induced JNK activation was p53 independent. Thus, we declare that ROS type has a key role in selective instigation of JNK/p38-MAPKs and JAK2-STAT3 pathways in SK-N-MC cells. Identifying these differential behaviors and mechanisms of hydrogen peroxide and superoxide anion functions illuminates the possible therapeutic targets in the prevention or treatment of ROS-induced neurodegenerative diseases such as Alzheimer's disease.

A germin-like protein with superoxide dismutase activity in pea nodules with high protein sequence identity to a putative rhicadhesin receptor.

PubMed

Gucciardo, Sébastian; Wisniewski, Jean-Pierre; Brewin, Nicholas J; Bornemann, Stephen

2007-01-01

The cDNAs encoding three germin-like proteins (PsGER1, PsGER2a, and PsGER2b) were isolated from Pisum sativum. The coding sequence of PsGER1 transiently expressed in tobacco leaves gave a protein with superoxide dismutase activity but no detectable oxalate oxidase activity according to in-gel activity stains. The transient expression of wheat germin gf-2.8 oxalate oxidase showed oxalate oxidase but no superoxide dismutase activity under the same conditions. The superoxide dismutase activity of PsGER1 was resistant to high temperature, denaturation by detergent, and high concentrations of hydrogen peroxide. In salt-stressed pea roots, a heat-resistant superoxide dismutase activity was observed with an electrophoretic mobility similar to that of the PsGER1 protein, but this activity was below the detection limit in non-stressed or H(2)O(2)-stressed pea roots. Oxalate oxidase activity was not detected in either pea roots or nodules. Following in situ hybridization in developing pea nodules, PsGER1 transcript was detected in expanding cells just proximal to the meristematic zone and also in the epidermis, but to a lesser extent. PsGER1 is the first known germin-like protein with superoxide dismutase activity to be associated with nodules. It shared protein sequence identity with the N-terminal sequence of a putative plant receptor for rhicadhesin, a bacterial attachment protein. However, its primary location in nodules suggests functional roles other than as a rhicadhesin receptor required for the first stage of bacterial attachment to root hairs.

Removal of H2O2 and generation of superoxide radical: Role of cytochrome c and NADH

PubMed Central

Velayutham, Murugesan; Hemann, Craig; Zweier, Jay L.

2011-01-01

In cells, mitochondria, endoplasmic reticulum, and peroxisomes are the major sources of reactive oxygen species (ROS) under physiological and pathophysiological conditions. Cytochrome c (cyt c) is known to participate in mitochondrial electron transport and has antioxidant and peroxidase activities. Under oxidative or nitrative stress, the peroxidase activity of Fe3+cyt c is increased. The level of NADH is also increased under pathophysiological conditions such as ischemia and diabetes and a concurrent increase in hydrogen peroxide (H2O2) production occurs. Studies were performed to understand the related mechanisms of radical generation and NADH oxidation by Fe3+cyt c in the presence of H2O2. Electron paramagnetic resonance (EPR) spin trapping studies using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) were performed with NADH, Fe3+cyt c, and H2O2 in the presence of methyl-β-cyclodextrin. An EPR spectrum corresponding to the superoxide radical adduct of DMPO encapsulated in methyl-β-cyclodextrin was obtained. This EPR signal was quenched by the addition of the superoxide scavenging enzyme Cu,Zn-superoxide dismutase (SOD1). The amount of superoxide radical adduct formed from the oxidation of NADH by the peroxidase activity of Fe3+cyt c increased with NADH and H2O2 concentration. From these results, we propose a mechanism in which the peroxidase activity of Fe3+cyt c oxidizes NADH to NAD•, which in turn donates an electron to O2 resulting in superoxide radical formation. A UV-visible spectroscopic study shows that Fe3+cyt c is reduced in the presence of both NADH and H2O2. Our results suggest that Fe3+cyt c could have a novel role in the deleterious effects of ischemia/reperfusion and diabetes due to increased production of superoxide radical. In addition, Fe3+cyt c may play a key role in the mitochondrial “ROS-induced ROS-release (RIRR)” signaling and in mitochondrial and cellular injury/death. The increased oxidation of NADH and generation of superoxide radical by this mechanism may have implications for the regulation of apoptotic cell death, endothelial dysfunction, and neurological diseases. We also propose an alternative electron transfer pathway, which may protect mitochondria and mitochondrial proteins from oxidative damage. PMID:21545835

CATALASE AND SUPEROXIDE DISMUTASE OF ROOT-COLONIZING SAPROPHYTIC FLUORESCENT PSEUDOMONADS

EPA Science Inventory

Root-colonizing, saprophytic fluorescent pseudomonads of the Pseudomonas putida-P. fluorescens group express similar levels of catalase and superoxide dismutase activities during growth on a sucrose- and amino acid-rich medium. ncreased specific activities of catalase but not sup...

Evidence that the reactivity of the martian soil is due to superoxide ions

NASA Technical Reports Server (NTRS)

Yen, A. S.; Kim, S. S.; Hecht, M. H.; Frant, M. S.; Murray, B.

2000-01-01

The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.

Monitoring the Effects of Acupoint Antioxidant Intervention by Measuring Electrical Potential Difference along the Meridian.

PubMed

Xu, Ming-Ming; Guo, Jing-Ke; Xu, Jin-Sen; Zhang, Chao-Xin; Liu, Shu-Tao; Liao, Ri-Tao; Lin, Chun-Tong; Guo, Jian-Hui; Rao, Ping-Fan

2015-01-01

Previous studies suggest that superoxide anions are possibly traveling along acupuncture meridians. The electrical potential difference (EPD) between acupoints may be related to the movement. To test the above hypothesis, we conducted a study investigating the effects of acupoint antioxidant interventions on the meridian EPD. Firstly, ST39 (L) and ST44 (L) were screened out for the EPD detection along the stomach meridian, and ST36 (L) was selected for interventions including acumassage with the control cream, as well as the TAT-SOD cream for 30 minutes, or injection with reduced glutathione sodium. The EPD between ST39 and ST44 was recorded for 80 minutes and measured again 48 h later. While the EPD increased during the acumassage, the acumassage with TAT-SOD cream and the glutathione injection generated waves of EPD increased, indicating the migration or removal from the visceral organ of a greater quantity of superoxide. Remarkably lower EPD readings 48 h later with both antioxidant acupoint interventions than the mere acumassage imply a more complete superoxide flushing out due to the restored superoxide pathway at the acupoint after interventions. The results confirm superoxide transportation along the meridians and demonstrate a possibility of acupoint EPD measurement as a tool to monitor changes in the meridians and acupoints.

Electrolyte Chemistry for Simultaneous Stabilization of Potassium Metal and Superoxide in K-O₂ Batteries.

PubMed

Xiao, Neng; Gourdin, Gerald; Wu, Yiying

2018-05-22

In the superoxide batteries based on O2/O2- redox chemistry, identifying an electrolyte to stabilize both alkali metal and superoxide remains challenging due to their reactivity towards electrolyte components. Bis(fluorosulfonyl)imide (FSI-) has been recognized as a "magical anion" for passivating alkali metals. Herein, we illustrate the chemical reactions between FSI- and superoxide, and the resultant dilemma when considering an anode-compatible electrolyte vs. a cathode-compatible one in K-O2 batteries. On one side, the KFSI-dimethoxyethane (DME) electrolyte passivates the potassium metal anode via the cleavage of S-F bond and formation of a KF-rich solid electrolyte interface (SEI). Nevertheless, the KFSI salt is chemically unstable due to the nucleophilic attack by superoxide and/or hydroxide species. On the other hand, potassium bis(trifluorosulfonyl)imide (KTFSI) is stable for KO2, but results in mossy deposition and irreversible plating and stripping. In order to circumvent this dilemma, we develop an artificial SEI for K metal anode to achieve long cycle-life K-O2 batteries. This work contributes to the understanding of electrolyte chemistry and guides the development of stable electrolytes and artificial SEI in metal-O2 batteries. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Superoxide and Peroxynitrite in Atherosclerosis

NASA Astrophysics Data System (ADS)

White, C. Roger; Brock, Tommy A.; Chang, Ling-Yi; Crapo, James; Briscoe, Page; Ku, David; Bradley, William A.; Gianturco, Sandra H.; Gore, Jeri; Freeman, Bruce A.; Tarpey, Margaret M.

1994-02-01

The role of reactive oxygen species in the vascular pathology associated with atherosclerosis was examined by testing the hypothesis that impaired vascular reactivity results from the reaction of nitric oxide (^.NO) with superoxide (O^-_2), yielding the oxidant peroxynitrite (ONOO^-). Contractility studies were performed on femoral arteries from rabbits fed a cholesterol-supplemented diet. Cholesterol feeding shifted the EC50 for acetylcholine (ACh)-induced relaxation and impaired the maximal response to ACh. We used pH-sensitive liposomes to deliver CuZn superoxide dismutase (SOD; superoxide:superoxide oxidoreductase, EC 1.15.1.1) to critical sites of ^.NO reaction with O^-_2. Intravenously injected liposomes (3000 units of SOD per ml) augmented ACh-induced relaxation in the cholesterol-fed group to a greater extent than in controls. Quantitative immunocytochemistry demonstrated enhanced distribution of SOD in both endothelial and vascular smooth muscle cells as well as in the extracellular matrix. SOD activity in vessel homogenates of liposome-treated rabbits was also increased. Incubation of β very low density lipoprotein with ONOO^- resulted in the rapid formation of conjugated dienes and thiobarbituric acid-reactive substances. Our results suggest that the reaction of O^-_2 with ^.NO is involved in the development of atherosclerotic disease by yielding a potent mediator of lipoprotein oxidation, as well as by limiting ^.NO stimulation of vascular smooth muscle guanylate cyclase activity.

Human Manganese Superoxide Dismutase Tyrosine 34 Contribution to Structure and Catalysis

PubMed Central

Perry, J. Jefferson P.; Hearn, Amy S.; Cabelli, Diane E.; Nick, Harry S.; Tainer, John A.; Silverman, David N.

2009-01-01

Superoxide dismutase (SOD) enzymes are critical in controlling levels of reactive oxygen species (ROS) that are linked to aging, cancer and neurodegenerative disease. Superoxide (O2 •−) produced during respiration is removed by the product of the SOD2 gene, the homotetrameric manganese superoxide dismutase (MnSOD). Here, we examine the structural and catalytic roles of the highly conserved active-site residue Tyr34, based upon structure-function studies of MnSOD enzymes with mutations at this site. Substitution of Tyr34 with five different amino acids retained the active site protein structure and assembly, but causes a substantial decrease in the catalytic rate constant for the reduction of superoxide. The rate constant for formation of product inhibition complex also decreases but to a much lesser extent, resulting in a net increase in the product inhibition form of the mutant enzymes. Comparisons of crystal structures and catalytic rates also suggest that one mutation, Y34V, interrupts the hydrogen-bonded network, which is associated with a rapid dissociation of the product-inhibited complex. Notably, with three of the Tyr34 mutants we also observe an intermediate in catalysis, which has not been reported previously. Thus, these mutants establish a means to trap a catalytic intermediate that promises to help elucidate the mechanism of catalysis. PMID:19265433

Propylthiouracil, Perchlorate, and Thyroid-Stimulating Hormone Modulate High Concentrations of Iodide Instigated Mitochondrial Superoxide Production in the Thyroids of Metallothionein I/II Knockout Mice

PubMed Central

Duan, Qi; Wang, Tingting; Zhang, Na; Perera, Vern; Liang, Xue; Abeysekera, Iruni Roshanie

2016-01-01

Background Increased oxidative stress has been suggested as one of the underlying mechanisms in iodide excess-induced thyroid disease. Metallothioneins (MTs) are regarded as scavengers of reactive oxygen species (ROS) in oxidative stress. Our aim is to investigate the effects of propylthiouracil (PTU), a thyroid peroxidase inhibitor, perchlorate (KClO4), a competitive inhibitor of iodide transport, and thyroid stimulating hormone (TSH) on mitochondrial superoxide production instigated by high concentrations of iodide in the thyroids of MT-I/II knockout (MT-I/II KO) mice. Methods Eight-week-old 129S7/SvEvBrd-Mt1tm1Bri Mt2tm1Bri/J (MT-I/II KO) mice and background-matched wild type (WT) mice were used. Results By using a mitochondrial superoxide indicator (MitoSOX Red), lactate dehydrogenase (LDH) release, and methyl thiazolyl tetrazolium (MTT) assay, we demonstrated that the decreased relative viability and increased LDH release and mitochondrial superoxide production induced by potassium iodide (100 µM) can be relieved by 300 µM PTU, 30 µM KClO4, or 10 U/L TSH in the thyroid cell suspensions of both MT-I/II KO and WT mice (P<0.05). Compared to the WT mice, a significant decrease in the relative viability along with a significant increase in LDH release and mitochondrial superoxide production were detected in MT-I/II KO mice(P<0.05). Conclusion We concluded that PTU, KClO4, or TSH relieved the mitochondrial oxidative stress induced by high concentrations of iodide in the thyroids of both MT-I/II KO and WT mice. MT-I/II showed antioxidant effects against high concentrations of iodide-induced mitochondrial superoxide production in the thyroid. PMID:26754589

Mitochondrial modulation-induced activation of vagal sensory neuronal subsets by antimycin A, but not CCCP or rotenone, correlates with mitochondrial superoxide production.

PubMed

Stanford, Katherine R; Taylor-Clark, Thomas E

2018-01-01

Inflammation causes nociceptive sensory neuron activation, evoking debilitating symptoms and reflexes. Inflammatory signaling pathways are capable of modulating mitochondrial function, resulting in reactive oxygen species (ROS) production, mitochondrial depolarization and calcium release. Previously we showed that mitochondrial modulation with antimycin A, a complex III inhibitor, selectively stimulated nociceptive bronchopulmonary C-fibers via the activation of transient receptor potential (TRP) ankyrin 1 (A1) and vanilloid 1 (V1) cation channels. TRPA1 is ROS-sensitive, but there is little evidence that TRPV1 is activated by ROS. Here, we used dual imaging of dissociated vagal neurons to investigate the correlation of mitochondrial superoxide production (mitoSOX) or mitochondrial depolarization (JC-1) with cytosolic calcium (Fura-2AM), following mitochondrial modulation by antimycin A, rotenone (complex I inhibitor) and carbonyl cyanide m-chlorophenyl hydrazone (CCCP, mitochondrial uncoupling agent). Mitochondrial modulation by all agents selectively increased cytosolic calcium in a subset of TRPA1/TRPV1-expressing (A1/V1+) neurons. There was a significant correlation between antimycin A-induced calcium responses and mitochondrial superoxide in wild-type 'responding' A1/V1+ neurons, which was eliminated in TRPA1-/- neurons, but not TRPV1-/- neurons. Nevertheless, antimycin A-induced superoxide production did not always increase calcium in A1/V1+ neurons, suggesting a critical role of an unknown factor. CCCP caused both superoxide production and mitochondrial depolarization but neither correlated with calcium fluxes in A1/V1+ neurons. Rotenone-induced calcium responses in 'responding' A1/V1+ neurons correlated with mitochondrial depolarization but not superoxide production. Our data are consistent with the hypothesis that mitochondrial dysfunction causes calcium fluxes in a subset of A1/V1+ neurons via ROS-dependent and ROS-independent mechanisms.

Superoxide anion stress attenuates the contractile response of the Guinea pig vas deferens to ATP and diadenosine tetraphosphate. Possible effect on calcium dysregulation.

PubMed

Al-Rawi, Mahmood B; Aleisa, Abdulaziz M; Khattab, Mahmoud M

2008-01-01

Induction of endogenous superoxide anion stress by the use of the superoxide dismutase inhibitor diethylthiocarbamate (DETCA; 10 mmol/l) produced a potent inhibition of the ATP (0.3-10 mmol/l) and diadenosine tetraphosphate (AP(4)A) contractile activity in the isolated vas deferens by 29-92 and 24-90%, respectively. Pyrogallol (0.1 mmol/l), the exogenous superoxide anion generator, produced a significant inhibition on the contractile activity of the vas deferens induced by ATP and AP(4)A by 33-89 and 25-82%, respectively. DETCA (10 mmol/l) and pyrogallol (0.1 mmol/l) attenuated the contractile response of isolated guinea pig vas deferens strips to the selective P2X agonist alpha,beta-methyleneATP (alpha,beta-meATP; 50 micromol/l) by 25 and 47%, respectively. In Ca(2+)-free high-K(+) (80 mmol/l) Krebs solution, pyrogallol and DETCA produced inhibition of the contractile response to alpha,beta-meATP (50 micromol/l) in similar way to that in normal Krebs solution. The further addition of CaCl(2) (1 mmol/l) abolished the inhibitory effects exerted by pyrogallol and DETCA. The control contractile response to alpha,beta-meATP (50 micromol/l) was not affected in Ca(2+)-free high-K(+) (80 mmol/l) Krebs solution. It may be concluded that superoxide anion stress produces a significant inhibitory effect on both mono- and di-nucleotide purinergic contraction of the vas deferens. Superoxide anion appears to interrupt the P2X(1)-mediated transduction cascade at some step(s) of intracellular calcium handling. Copyright 2008 S. Karger AG, Basel.

Simultaneous determination of superoxide and hydrogen peroxide in macrophage RAW 264.7 cell extracts by microchip electrophoresis with laser-induced fluorescence detection.

PubMed

Li, Hongmin; Li, Qingling; Wang, Xu; Xu, Kehua; Chen, Zhenzhen; Gong, Xiaocong; Liu, Xin; Tong, Lili; Tang, Bo

2009-03-15

A method for the first time to simultaneously determine superoxide and hydrogen peroxide in macrophage RAW 264.7 cell extracts by microchip electrophoresis with laser-induced fluorescence detection (MCE-LIF) was developed. 2-Chloro-1,3-dibenzothiazolinecyclohexene (DBZTC) and bis(p-methylbenzenesulfonyl) dichlorofluorescein (FS), two probes that can be specifically derivatized by superoxide and hydrogen peroxide, respectively, were synthesized and used. Parameters influencing the derivatization and on-chip separation were optimized. With the use of a HEPES (20 mM, pH 7.4) running buffer, a 50 mm long separation channel, and a separation voltage of 1800 V, baseline separation was achieved within 48 s for the two derivatization products, DBZTC-oxide (DBO) and 2,7-dichlorofluorescein (DCF). The linearity ranges of the method were 0.08-5.0 and 0.02-5.0 microM with detection limits (signal-to-noise ratio = 3) of 10 nM (1.36 amol) and 5.6 nM (0.76 amol) for superoxide and hydrogen peroxide, respectively. The relative standard deviations (RSDs) of migration time and peak area were less than 2.0% and 5.0%, respectively. The recoveries of the cell extract samples spiked with 1.0 microM standard solutions were 96.1% and 93.0% for superoxide and hydrogen peroxide, respectively. With the use of this method, superoxide and hydrogen peroxide in phorbol myristate acetate (PMA)-stimulated macrophage RAW 264.7 cell extracts were found to be 0.78 and 1.14 microM, respectively. The method has paved a way for simultaneously determining two or more reactive oxygen species (ROS) in a biological system with high resolution.

Effects of OPC-6535 on lipopolysaccharide-induced acute liver injury in the rat: involvement of superoxide and tumor necrosis factor-alpha from hepatic macrophages.

PubMed

Hasegawa, Tadashi; Sakurai, Kazushi; Kambayashi, Yasuhiro; Saniabadi, Abby R; Nagamoto, Hisashi; Tsukada, Katsuhiko; Takahashi, Atsushi; Kuwano, Hiroyuki; Nakano, Minoru

2003-11-01

The objective of this study was to investigate the effects of OPC-6535 on Propionibacterium acnes-primed and lipopolysaccharide-induced liver injury in the rat. P. acnes was administered intravenously to the rat at 16 mg/kg 7 days before the experiments. In liver perfusion experiments, lipopolysaccharide was mixed in perfusion buffer at 2.5 microg/mL. The chemiluminescence method and histochemical reduction of nitro blue tetrazolium were used for detecting superoxide. Release of cytokines into the perfusate was examined. In in vivo experiments, lipopolysaccharide was administered intravenously to the rat at 200 microg/kg. Concentrations of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and cytokines were determined in the plasma, and myeloperoxidase activity was measured in the liver tissue. OPC-6535 was given intravenously at 1 mg/kg 30 minutes before lipopolysaccharide challenge, and was then, in perfusion experiments, added to the buffer at 10 micromol/L. In perfusion experiments, P. acnes and lipopolysaccharide caused dramatic production of superoxide, tumor necrosis factor-alpha (TNF-alpha) and growth-related oncogene/cytokine-induced neutrophil chemoattractant-1 (GRO/CINC-1). Superoxide was mainly from hepatic macrophages. Treatment with OPC-6535 suppressed superoxide and TNF-alpha but did not affect GRO/CINC-1. In in vivo experiments, P. acnes and lipopolysaccharide increased the level of TNF-alpha, GRO/CINC-1, AST and ALT in the plasma, and myeloperoxidase activity in the liver. OPC-6535 reduced TNF-alpha, AST, and ALT, but did not affect GRO/CINC-1 or myeloperoxidase. Attenuation of liver injury by OPC-6535 is believed to be due to its inhibitory effects on superoxide and TNF-alpha production by hepatic macrophages in P. acnes- and lipopolysaccharide-treated rats.

SUPEROXIDE-DEPENDENT IRON UPTAKE: A NEW ROLE FOR ANION EXCHANGE PROTEIN 2

EPA Science Inventory

Lung cells import iron across the plasma membrane as ferrous (Fe2+) ion by incompletely understood mechanisms. We tested the hypothesis that human bronchial epithelial (HBE) cells import non-transferrin-bound iron (NTBI) using superoxide-dependent ferri-reductase activity involvi...

URBAN PARTICLE-INDUCED PULMONARY ARTERY CONSTRUCTION IS MEDIATED BY SUPEROXIDE PRODUCTION

EPA Science Inventory

URBAN PARTICLE-INDUCED PULMONARY ARTERY CONSTRICTION IS MEDIATED BY SUPEROXIDE PRODUCTION.Jacqueline D. Carter, Zhuowei Li, Lisa A. Dailey, Yuh-Chin T. Huang. CEMALB, University of North Carolina, and ORD, US EPA, Chapel Hill, North Carolina.

Exposure to particulate matter...

Novel synthesis approach for stable sodium superoxide (NaO2) nanoparticles for LPG sensing application

NASA Astrophysics Data System (ADS)

Nemade, Kailash; Waghuley, Sandeep

2017-05-01

The synthesis of stable superoxide is still great challenge for the researchers working in the field of materials science. Through this letter, we report the novel and simple synthesis approach for the preparation of stable sodium superoxide (NaO2) nanoparticles. NaO2 nanoparticles were prepared by a spray pyrolysis technique, under oxygen rich environment for gas sensing application. The texture characterizations show that as-obtained NaO2 nanoparticles have high structural purity. Most importantly, NaO2 nanoparticles exhibits higher sensing response, shorter response time and recovery time, low operating temperature and good stability during sensing of liquefied petroleum gas (LPG). The main accomplishment of present work is that as-fabricated sensor has low operating temperature (423 K), which is below auto-ignition temperature of LPG. The gas sensing mechanism of NaO2 nanoparticles was discussed without the conventional oxygen bridging mechanism. Through this short communication, LPG sensing application of stable sodium superoxide nanoparticle is explored.

Mitochondrial complex I deactivation is related to superoxide production in acute hypoxia.

PubMed

Hernansanz-Agustín, Pablo; Ramos, Elena; Navarro, Elisa; Parada, Esther; Sánchez-López, Nuria; Peláez-Aguado, Laura; Cabrera-García, J Daniel; Tello, Daniel; Buendia, Izaskun; Marina, Anabel; Egea, Javier; López, Manuela G; Bogdanova, Anna; Martínez-Ruiz, Antonio

2017-08-01

Mitochondria use oxygen as the final acceptor of the respiratory chain, but its incomplete reduction can also produce reactive oxygen species (ROS), especially superoxide. Acute hypoxia produces a superoxide burst in different cell types, but the triggering mechanism is still unknown. Herein, we show that complex I is involved in this superoxide burst under acute hypoxia in endothelial cells. We have also studied the possible mechanisms by which complex I could be involved in this burst, discarding reverse electron transport in complex I and the implication of PTEN-induced putative kinase 1 (PINK1). We show that complex I transition from the active to 'deactive' form is enhanced by acute hypoxia in endothelial cells and brain tissue, and we suggest that it can trigger ROS production through its Na + /H + antiporter activity. These results highlight the role of complex I as a key actor in redox signalling in acute hypoxia. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

THE WATER-WATER CYCLE IN CHLOROPLASTS: Scavenging of Active Oxygens and Dissipation of Excess Photons.

PubMed

Asada, Kozi

1999-06-01

Photoreduction of dioxygen in photosystem I (PSI) of chloroplasts generates superoxide radicals as the primary product. In intact chloroplasts, the superoxide and the hydrogen peroxide produced via the disproportionation of superoxide are so rapidly scavenged at the site of their generation that the active oxygens do not inactivate the PSI complex, the stromal enzymes, or the scavenging system itself. The overall reaction for scavenging of active oxygens is the photoreduction of dioxygen to water via superoxide and hydrogen peroxide in PSI by the electrons derived from water in PSII, and the water-water cycle is proposed for these sequences. An overview is given of the molecular mechanism of the water-water cycle and microcompartmentalization of the enzymes participating in it. Whenever the water-water cycle operates properly for scavenging of active oxygens in chloroplasts, it also effectively dissipates excess excitation energy under environmental stress. The dual functions of the water-water cycle for protection from photoinihibition are discussed.

Metabolic Regulation of Manganese Superoxide Dismutase Expression via Essential Amino Acid Deprivation*

PubMed Central

Aiken, Kimberly J.; Bickford, Justin S.; Kilberg, Michael S.; Nick, Harry S.

2008-01-01

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging. PMID:18187411

Metabolic regulation of manganese superoxide dismutase expression via essential amino acid deprivation.

PubMed

Aiken, Kimberly J; Bickford, Justin S; Kilberg, Michael S; Nick, Harry S

2008-04-18

Organisms respond to available nutrient levels by rapidly adjusting metabolic flux, in part through changes in gene expression. A consequence of adaptations in metabolic rate is the production of mitochondria-derived reactive oxygen species. Therefore, we hypothesized that nutrient sensing could regulate the synthesis of the primary defense of the cell against superoxide radicals, manganese superoxide dismutase. Our data establish a novel nutrient-sensing pathway for manganese superoxide dismutase expression mediated through essential amino acid depletion concurrent with an increase in cellular viability. Most relevantly, our results are divergent from current mechanisms governing amino acid-dependent gene regulation. This pathway requires the presence of glutamine, signaling via the tricarboxylic acid cycle/electron transport chain, an intact mitochondrial membrane potential, and the activity of both the MEK/ERK and mammalian target of rapamycin kinases. Our results provide evidence for convergence of metabolic cues with nutrient control of antioxidant gene regulation, revealing a potential signaling strategy that impacts free radical-mediated mutations with implications in cancer and aging.

The Na+-Translocating NADH:Quinone Oxidoreductase Enhances Oxidative Stress in the Cytoplasm of Vibrio cholerae

PubMed Central

Muras, Valentin; Dogaru-Kinn, Paul; Minato, Yusuke; Häse, Claudia C.

2016-01-01

ABSTRACT We searched for a source of reactive oxygen species (ROS) in the cytoplasm of the human pathogen Vibrio cholerae and addressed the mechanism of ROS formation using the dye 2′,7′-dichlorofluorescein diacetate (DCFH-DA) in respiring cells. By comparing V. cholerae strains with or without active Na+-translocating NADH:quinone oxidoreductase (Na+-NQR), this respiratory sodium ion redox pump was identified as a producer of ROS in vivo. The amount of cytoplasmic ROS detected in V. cholerae cells producing variants of Na+-NQR correlated well with rates of superoxide formation by the corresponding membrane fractions. Membranes from wild-type V. cholerae showed increased superoxide production activity (9.8 ± 0.6 μmol superoxide min−1 mg−1 membrane protein) compared to membranes from the mutant lacking Na+-NQR (0.18 ± 0.01 μmol min−1 mg−1). Overexpression of plasmid-encoded Na+-NQR in the nqr deletion strain resulted in a drastic increase in the formation of superoxide (42.6 ± 2.8 μmol min−1 mg−1). By analyzing a variant of Na+-NQR devoid of quinone reduction activity, we identified the reduced flavin adenine dinucleotide (FAD) cofactor of cytoplasmic NqrF subunit as the site for intracellular superoxide formation in V. cholerae. The impact of superoxide formation by the Na+-NQR on the virulence of V. cholerae is discussed. IMPORTANCE In several studies, it was demonstrated that the Na+-NQR in V. cholerae affects virulence in a yet unknown manner. We identified the reduced FAD cofactor in the NADH-oxidizing NqrF subunit of the Na+-NQR as the site of superoxide formation in the cytoplasm of V. cholerae. Our study provides the framework to understand how reactive oxygen species formed during respiration could participate in the regulated expression of virulence factors during the transition from aerobic to microaerophilic (intestinal) habitats. This hypothesis may turn out to be right for many other pathogens which, like V. cholerae, depend on the Na+-NQR as the sole electrogenic NADH dehydrogenase. PMID:27325677

Ursolic Acid Inhibits Superoxide Production in Activated Neutrophils and Attenuates Trauma-Hemorrhage Shock-Induced Organ Injury in Rats

PubMed Central

Hwang, Tsong-Long; Shen, Hsin-I; Liu, Fu-Chao; Tsai, Hsin-I; Wu, Yang-Chang; Chang, Fang-Rong; Yu, Huang-Ping

2014-01-01

Neutrophil activation is associated with the development of organ injury after trauma–hemorrhagic shock. In the present study, ursolic acid inhibited the superoxide anion generation and elastase release in human neutrophils. Administration of ursolic acid attenuated trauma–hemorrhagic shock-induced hepatic and lung injuries in rats. In addition, administration of ursolic acid attenuated the hepatic malondialdehyde levels and reduced the plasma aspartate aminotransferase and alanine aminotransferase levels after trauma–hemorrhagic shock. In conclusion, ursolic acid, a bioactive natural compound, inhibits superoxide anion generation and elastase release in human neutrophils and ameliorates trauma–hemorrhagic shock-induced organ injury in rats. PMID:25360589

Evolutionary conservativeness of electric field in the Cu,Zn superoxide dismutase active site. Evidence for co-ordinated mutation of charged amino acid residues.

PubMed

Desideri, A; Falconi, M; Polticelli, F; Bolognesi, M; Djinovic, K; Rotilio, G

1992-01-05

Equipotential lines were calculated, using the Poisson-Boltzmann equation, for six Cu,Zn superoxide dismutases with different protein electric charge and various degrees of sequence homology, namely those from ox, pig, sheep, yeast, and the isoenzymes A and B from the amphibian Xenopus laevis. The three-dimensional structures of the porcine and ovine superoxide dismutases were obtained by molecular modelling reconstruction using the structure of the highly homologous bovine enzyme as a template. The three-dimensional structure of the evolutionary distant yeast Cu,Zn superoxide dismutase was recently resolved by us, while computer-modelled structures are available for X. laevis isoenzymes. The six proteins display large differences in the net protein charge and distribution of electrically charged surface residues but the trend of the equipotential lines in the proximity of the active sites was found to be constant in all cases. These results are in line with the very similar catlytic rate constants experimentally measured for the corresponding enzyme activities. This analysis shows that electrostatic guidance for the enzyme-substrate interaction in Cu,Zn superoxide dismutases is related to a spatial distribution of charges, arranged so as to maintain, in the area surrounding the active sites, an identical electrostatic potential distribution, which is conserved in the evolution of this protein family.

Characterization of the Bacillus stearothermophilus manganese superoxide dismutase gene and its ability to complement copper/zinc superoxide dismutase deficiency in Saccharomyces cerevisiae

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bowler, C.; Inze, D.; Van Camp, W.

1990-03-01

Recombinant clones containing the manganese superoxide dismutase (MnSOD) gene of Bacillus stearothermophilus were isolated with an oligonucleotide probe designed to match a part of the previously determined amino acid sequence. Complementation analyses, performed by introducing each plasmid into a superoxide dismutase-deficient mutant of Escherichia coli, allowed us to define the region of DNA which encodes the MnSOD structural gene and to identify a promoter region immediately upstream from the gene. These data were subsequently confirmed by DNA sequencing. Since MnSOD is normally restricted to the mitochondria in eucaryotes, we were interested (i) in determining whether B. stearothermophilus MnSOD could functionmore » in eucaryotic cytosol and (ii) in determining whether MnSOD could replace the structurally unrelated copper/zinc superoxide dismutase (Cu/ZnSOD) which is normally found there. To test this, the sequence encoding bacterial MnSOD was cloned into a yeast expression vector and subsequently introduced into a Cu/ZnSOD-deficient mutant of the yeast Saccharomyces cerevisiae. Functional expression of the protein was demonstrated, and complementation tests revealed that the protein was able to provide tolerance at wild-type levels to conditions which are normally restrictive for this mutant. Thus, in spite of the evolutionary unrelatedness of these two enzymes, Cu/ZnSOD can be functionally replaced by MnSOD in yeast cytosol.« less

NOX5 in Human Spermatozoa

PubMed Central

Musset, Boris; Clark, Robert A.; DeCoursey, Thomas E.; Petheo, Gabor L.; Geiszt, Miklos; Chen, Yumin; Cornell, John E.; Eddy, Carlton A.; Brzyski, Robert G.; El Jamali, Amina

2012-01-01

Physiological and pathological processes in spermatozoa involve the production of reactive oxygen species (ROS), but the identity of the ROS-producing enzyme system(s) remains a matter of speculation. We provide the first evidence that NOX5 NADPH oxidase is expressed and functions in human spermatozoa. Immunofluorescence microscopy detected NOX5 protein in both the flagella/neck region and the acrosome. Functionally, spermatozoa exposed to calcium ionophore, phorbol ester, or H2O2 exhibited superoxide anion production, which was blocked by addition of superoxide dismutase, a Ca2+ chelator, or inhibitors of either flavoprotein oxidases (diphenylene iododonium) or NOX enzymes (GKT136901). Consistent with our previous overexpression studies, we found that H2O2-induced superoxide production by primary sperm cells was mediated by the non-receptor tyrosine kinase c-Abl. Moreover, the HV1 proton channel, which was recently implicated in spermatozoa motility, was required for optimal superoxide production by spermatozoa. Immunoprecipitation experiments suggested an interaction among NOX5, c-Abl, and HV1. H2O2 treatment increased the proportion of motile sperm in a NOX5-dependent manner. Statistical analyses showed a pH-dependent correlation between superoxide production and enhanced sperm motility. Collectively, our findings show that NOX5 is a major source of ROS in human spermatozoa and indicate a role for NOX5-dependent ROS generation in human spermatozoa motility. PMID:22291013

Intracellular implantation of enzymes in hollow silica nanospheres for protein therapy: cascade system of superoxide dismutase and catalase.

PubMed

Chang, Feng-Peng; Chen, Yi-Ping; Mou, Chung-Yuan

2014-11-01

An approach for enzyme therapeutics is elaborated with cell-implanted nanoreactors that are based on multiple enzymes encapsulated in hollow silica nanospheres (HSNs). The synthesis of HSNs is carried out by silica sol-gel templating of water-in-oil microemulsions so that polyethyleneimine (PEI) modified enzymes in aqueous phase are encapsulated inside the HSNs. PEI-grafted superoxide dismutase (PEI-SOD) and catalase (PEI-CAT) encapsulated in HSNs are prepared with quantitative control of the enzyme loadings. Excellent activities of superoxide dismutation by PEI-SOD@HSN are found and transformation of H2 O2 to water by PEI-CAT@HSN. When PEI-SOD and PEI-CAT are co-encapsulated, cascade transformation of superoxide through hydrogen peroxide to water was facile. Substantial fractions of HSNs exhibit endosome escape to cytosol after their delivery to cells. The production of downstream reactive oxygen species (ROS) and COX-2/p-p38 expression show that co-encapsulated SOD/CAT inside the HSNs renders the highest cell protection against the toxicant N,N'-dimethyl-4,4'-bipyridinium dichloride (paraquat). The rapid cell uptake and strong detoxification effect on superoxide radicals by the SOD/CAT-encapsulated hollow mesoporous silica nanoparticles demonstrate the general concept of implanting catalytic nanoreactors in biological cells with designed functions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Metabolic activity of neutrophilic granulocytes and possible ways of its correction in patients with acute coronary syndrome].

PubMed

Ryzhkova, N A; Havrylenko, T I; Parkhomenko, O M; Kozhukhov, S M

2011-01-01

The present study aimed to investigate the metabolic activity of neutrocytes and the action of corvitin on the level of superoxide anion and myeloperoxidases of cells in vitro with the calculation of index of consumption of myeloperoxidase in patients with ST-elevation acute coronary syndrome. Patient were divided into 2 groups according to the level of superoxide anion. Group 1 included the patients (68%) with the initially low level of superoxide anion, and adding of corvitin to the cells of such patients promoted normalization of this index. In this group we observed also neutrocytosis, low index of consumption of myeloperoxidase and a high level of this enzyme in general population of neutrocytes. Group 2 included patients (32%) with initially normal level of superoxide anion. In this group, corvitin did not influence substantially this factor. Such patients had a level ofmyeloperoxidase within control values and the index of consumption of this enzyme was also within control values. The analysis of hospital period showed that the patients of group 1 had a higher frequency of ventricular tachycardia/ventricular fibrillation, paroxysms of atrial fibrillation, bundle-branch blocks and worsening of the kidney function. We suppose that a low level of superoxide anion in neutrocytes play a major role in the development of complications in patients with acute coronary syndrome. An intravenous administration of corvitin was effective in restoring the metabolic activity of neutrocytes.

Contractile activity of ATP and diadenosine tetraphosphate on urinary bladder in the rats: role of superoxide anion and urothelium.

PubMed

Khattab, M M; Al-Hrasen, M N

2006-04-01

Both ATP and diadenosine tetraphosphate (AP(4)A) produced a dose-dependent contraction of rat isolated urinary bladder rings. The AP(4)A dose-response curve was to the left of that of ATP, and the maximum response was greater than that produced by ATP. Mechanical removal of the urothelium increased the contractile response to ATP by between 53% and 71%, and that to AP(4)A by 42% (at highest AP(4)A concentration) to 68% at lower concentration. Inhibition of Cu/Zn superoxide dismutase with diethylthiocarbamate (DETCA, 5 mm) significantly reduced the ATP-evoked contraction by 31% (at high ATP concentration) to 40% at low ATP concentration. Similarly, the AP(4)A-induced contractions were significantly decreased by 27% at low AP(4)A level to 38% at higher concentrations. Induction of exogenous superoxide anion stress by the use of the superoxide anion generator, pyrogallol (0.5 mm), significantly decreased both ATP- and AP(4)A-induced contractions of the rat urinary bladder over the whole dose range. Contractile responses to ATP decreased by 36-40%, and those to AP(4)A by 44-49%. In conclusion, the urinary bladder urothelium exerts an inhibitory control over the purinergic contractility produced by adenine mononucleotides and dinucleotides. Superoxide anion stress, whether endogenous or exogenous, attenuates the ATP-induced as well as AP(4)A-induced contractility.

Function of Oxygen Resistance Proteins in the Anaerobic, Sulfate-Reducing Bacterium Desulfovibrio vulgaris Hildenborough

PubMed Central

Fournier, Marjorie; Zhang, Yi; Wildschut, Janine D.; Dolla, Alain; Voordouw, Johanna K.; Schriemer, David C.; Voordouw, Gerrit

2003-01-01

Two mutant strains of Desulfovibrio vulgaris Hildenborough lacking either the sod gene for periplasmic superoxide dismutase or the rbr gene for rubrerythrin, a cytoplasmic hydrogen peroxide (H2O2) reductase, were constructed. Their resistance to oxidative stress was compared to that of the wild-type and of a sor mutant lacking the gene for the cytoplasmic superoxide reductase. The sor mutant was more sensitive to exposure to air or to internally or externally generated superoxide than was the sod mutant, which was in turn more sensitive than the wild-type strain. No obvious oxidative stress phenotype was found for the rbr mutant, indicating that H2O2 resistance may also be conferred by two other rbr genes in the D. vulgaris genome. Inhibition of Sod activity by azide and H2O2, but not by cyanide, indicated it to be an iron-containing Sod. The positions of Fe-Sod and Sor were mapped by two-dimensional gel electrophoresis (2DE). A strong decrease of Sor in continuously aerated cells, indicated by 2DE, may be a critical factor in causing cell death of D. vulgaris. Thus, Sor plays a key role in oxygen defense of D. vulgaris under fully aerobic conditions, when superoxide is generated mostly in the cytoplasm. Fe-Sod may be more important under microaerophilic conditions, when the periplasm contains oxygen-sensitive, superoxide-producing targets. PMID:12486042

Potentiating antibiotics in drug-resistant clinical isolates via stimuli-activated superoxide generation.

PubMed

Courtney, Colleen M; Goodman, Samuel M; Nagy, Toni A; Levy, Max; Bhusal, Pallavi; Madinger, Nancy E; Detweiler, Corrella S; Nagpal, Prashant; Chatterjee, Anushree

2017-10-01

The rise of multidrug-resistant (MDR) bacteria is a growing concern to global health and is exacerbated by the lack of new antibiotics. To treat already pervasive MDR infections, new classes of antibiotics or antibiotic adjuvants are needed. Reactive oxygen species (ROS) have been shown to play a role during antibacterial action; however, it is not yet understood whether ROS contribute directly to or are an outcome of bacterial lethality caused by antibiotics. We show that a light-activated nanoparticle, designed to produce tunable flux of specific ROS, superoxide, potentiates the activity of antibiotics in clinical MDR isolates of Escherichia coli , Salmonella enterica , and Klebsiella pneumoniae . Despite the high degree of antibiotic resistance in these isolates, we observed a synergistic interaction between both bactericidal and bacteriostatic antibiotics with varied mechanisms of action and our superoxide-producing nanoparticles in more than 75% of combinations. As a result of this potentiation, the effective antibiotic concentration of the clinical isolates was reduced up to 1000-fold below their respective sensitive/resistant breakpoint. Further, superoxide-generating nanoparticles in combination with ciprofloxacin reduced bacterial load in epithelial cells infected with S. enterica serovar Typhimurium and increased Caenorhabditis elegans survival upon infection with S. enterica serovar Enteriditis, compared to antibiotic alone. This demonstration highlights the ability to engineer superoxide generation to potentiate antibiotic activity and combat highly drug-resistant bacterial pathogens.

Increased oxidative stress in the mitochondria isolated from lymphocytes of bipolar disorder patients during depressive episodes.

PubMed

Valvassori, Samira S; Bavaresco, Daniela V; Feier, Gustavo; Cechinel-Recco, Kelen; Steckert, Amanda V; Varela, Roger B; Borges, Cenita; Carvalho-Silva, Milena; Gomes, Lara M; Streck, Emílio L; Quevedo, João

2018-06-01

The present study aims to investigate the oxidative stress parameters in isolated mitochondria, as well as looking at mitochondrial complex activity in patients with Bipolar Disorder (BD) during depressive or euthymic episodes. This study evaluated the levels of mitochondrial complex (I, II, II-III and IV) activity in lymphocytes from BD patients. We evaluated the following oxidative stress parameters: superoxide, thiobarbituric acid reactive species (TBARS) and carbonyl levels in submitochondrial particles of lymphocytes from bipolar patients. 51 bipolar patients were recruited into this study: 34 in the euthymic phase, and 17 in the depressive phase. Our results indicated that the depressive phase could increase the levels of mitochondrial superoxide, carbonyl and TBARS, and superoxide dismutase, and could decrease the levels of mitochondrial complex II activity in the lymphocytes of bipolar patients. It was also observed that there was a negative correlation between the Hamilton Depression Rating Scale (HDRS) and complex II activity in the lymphocytes of depressive bipolar patients. In addition, there was a positive correlation between HDRS and superoxide, superoxide dismutase, TBARS and carbonyl. Additionally, there was a negative correlation between complex II activity and oxidative stress parameters. In conclusion, our results suggest that mitochondrial oxidative stress and mitochondrial complex II dysfunction play important roles in the depressive phase of BD. Copyright © 2018. Published by Elsevier B.V.

Superoxide dismutase activity in mesocarp tissue from divergent Cucumis melo L. genotypes

USDA-ARS?s Scientific Manuscript database

Muskmelon (Cucumis melo L.) fruit matrix is unique among plant foods in being able to provide a protective medium in which the antioxidant activity of the enzyme superoxide dismutase (SOD) is preserved during the digestive process, and therefore, being able to elicit in vivo pharmacological effects ...

Exogenous superoxide dismutase may lose its antidotal ability on rice leaves

USDA-ARS?s Scientific Manuscript database

Leaf diffusates of the resistant rice cultivars suppressed spore germination of blast fungus (Magnaporthe grisea). Bovine Cu-Zn superoxide dismutase (SOD) added to the diffusate abolished its toxicity. However, the enzyme added to the inoculum did not affect the toxicity of the diffusate. Even the s...

Synthesis of calcium superoxide

NASA Technical Reports Server (NTRS)

Rewick, R. T.; Blucher, W. G.; Estacio, P. L.

1972-01-01

Efforts to prepare Ca(O2) sub 2 from reactions of calcium compounds with 100% O3 and with O(D-1) atoms generated by photolysis of O3 at 2537 A are described. Samples of Ca(OH) sub 2, CaO, CaO2, Ca metal, and mixtures containing suspected impurities to promote reaction have been treated with excess O3 under static and flow conditions in the presence and absence of UV irradiation. Studies with KO2 suggest that the superoxide anion is stable to radiation at 2537 A but reacts with oxygen atoms generated by the photolysis of O3 to form KO3. Calcium superoxide is expected to behave in an analogous.

Parasitization by Scleroderma guani influences expression of superoxide dismutase genes in Tenebrio molitor

USDA-ARS?s Scientific Manuscript database

Superoxide dismutase (SOD) is an antioxidant enzyme involved in detoxifying reactive oxygen species. In this study, we identified genes encoding the extracellular and intracellular copper-zinc SODs (ecCuZnSOD and icCuZnSOD) and a manganese SOD (MnSOD) in the yellow mealworm beetle, Tenebrio molitor....

Adaptation of Staphylococcus aureus to Airway Environments in Patients With Cystic Fibrosis by Upregulation of Superoxide Dismutase M and Iron-Scavenging Proteins.

PubMed

Treffon, Janina; Block, Desiree; Moche, Martin; Reiss, Swantje; Fuchs, Stephan; Engelmann, Susanne; Becher, Dörte; Langhanki, Lars; Mellmann, Alexander; Peters, Georg; Kahl, Barbara C

2018-04-11

Adaptation of S. aureus to the hostile environment of CF airways resulted in changed abundance of proteins involved in energy metabolism, cellular processes, transport and binding, but most importantly in an iron-scavenging phenotype and increased activity of superoxide dismutase M.

Molecular Cloning and Expression of Sequence Variants of Manganese Superoxide Dismutase Genes from Wheat

USDA-ARS?s Scientific Manuscript database

Reactive oxygen species (ROS) are very harmful to living organisms due to the potential oxidation of membrane lipids, DNA, proteins, and carbohydrates. Transformed E.coli strain QC 871, superoxide dismutase (SOD) double-mutant, with three sequence variant MnSOD1, MnSOD2, and MnSOD3 manganese supero...

Oxygen activation at the plasma membrane: relation between superoxide and hydroxyl radical production by isolated membranes.

PubMed

Heyno, Eiri; Mary, Véronique; Schopfer, Peter; Krieger-Liszkay, Anja

2011-07-01

Production of reactive oxygen species (hydroxyl radicals, superoxide radicals and hydrogen peroxide) was studied using EPR spin-trapping techniques and specific dyes in isolated plasma membranes from the growing and the non-growing zones of hypocotyls and roots of etiolated soybean seedlings as well as coleoptiles and roots of etiolated maize seedlings. NAD(P)H mediated the production of superoxide in all plasma membrane samples. Hydroxyl radicals were only produced by the membranes of the hypocotyl growing zone when a Fenton catalyst (FeEDTA) was present. By contrast, in membranes from other parts of the seedlings a low rate of spontaneous hydroxyl radical formation was observed due to the presence of small amounts of tightly bound peroxidase. It is concluded that apoplastic hydroxyl radical generation depends fully, or for the most part, on peroxidase localized in the cell wall. In soybean plasma membranes from the growing zone of the hypocotyl pharmacological tests showed that the superoxide production could potentially be attributed to the action of at least two enzymes, an NADPH oxidase and, in the presence of menadione, a quinone reductase.

Radical scavenging ability of some compounds isolated from Piper cubeba towards free radicals.

PubMed

Aboul-Enein, Hassan Y; Kładna, Aleksandra; Kruk, Irena

2011-01-01

The purpose of this study was to identify the antioxidant activity of 16 compounds isolated from Piper cubeba (CNCs) through the extent of their capacities to scavenge free radicals, hydroxyl radical (HO(•)), superoxide anion radical O•(2)(-) and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(•)), in different systems. Electron paramagnetic resonance (EPR) and 5,5-dimethyl-1-pyrroline-N-oxide, DMPO, as the spin trap, and chemiluminescence techniques were applied. Using the Fenton-like reaction [Fe(II) + H(2)O(2)], CNCs were found to inhibit DMPO-OH radical formation ranging from 5 to 57% at 1.25 mmol L(-1) concentration. The examined CNCs also showed a high DPPH antiradical activity (ranging from 15 to 99% at 5 mmol L(-1) concentration). Furthermore, the results indicated that seven of the 16 tested compounds may catalyse the conversion of superoxide radicals generated in the potassium superoxide/18-crown-6 ether system, thus showing superoxide dismutase-like activity. The data obtained suggest that radical scavenging properties of CNCs might have potential application in many plant medicines. Copyright © 2010 John Wiley & Sons, Ltd.

[Oxidative Stress Level of Vanadium-exposed Workers].

PubMed

Wei, Teng-da; Li, Shun-pin; Liu, Yun-xing; Tan, Chun-ping; Li, Juan; Zhang, Zu-hui; Lan, Ya-jia; Zhang, Qin

2015-11-01

To determine the oxidative stress level in peripheral blood of vanadium-exposed workers, as an indication of population health effect of vanadium on human neurobehavioral system. 86 vanadium-exposed workers and 65 non-exposed workers were recruited by cluster sampling. A questionnaire was administered to collect demographic and occupational exposure information. Serum activity of superoxide dismutase (SOD), inducible nitric oxide synthase (iNOS) and malonaldehyde (MDA) contents were detected by kit assay. The differences in oxidative stress level between vanadium-exposed and non-exposed workers were compared. Vanadium-exposed workers had higher levels of MDA contents than the controls. The total superoxide dismutase(T-SOD) activity in vanadium-exposed workers was significantly lower than that in the controls, which was associated with lowered levels of manganese superoxide dismutase (Mn-SOD) activity. No changes in serum levels of cupro-zinc superoxide dismutase (CuZn-SOD) was found in vanadium-exposed workers. No difference in iNOS activity was found between vanadium-exposed workers and controls. Vanadium exposure increases free radical production in serum and reduces antioxidant capacity. But the relationship between vanadium exposure and iNOS damage remains uncertain.

Exploiting algal NADPH oxidase for biophotovoltaic energy

DOE PAGES

Anderson, Alexander; Laohavisit, Anuphon; Blaby, Ian K.; ...

2015-01-29

Photosynthetic microbes exhibit light-dependent electron export across the cell membrane, which can generate electricity in biological photovoltaic (BPV) devices. How electrons are exported remains to be determined; the identification of mechanisms would help selection or generation of photosynthetic microbes capable of enhanced electrical output. We show that plasma membrane NADPH oxidase activity is a significant component of light-dependent generation of electricity by the unicellular green alga Chlamydomonas reinhardtii. NADPH oxidases export electrons across the plasma membrane to form superoxide anion from oxygen. The C. reinhardtii mutant lacking the NADPH oxidase encoded by RBO1 is impaired in both extracellular superoxide anionmore » production and current generation in a BPV device. Complementation with the wild-type gene restores both capacities, demonstrating the role of the enzyme in electron export. Monitoring light-dependent extracellular superoxide production with a colorimetric assay is shown to be an effective way of screening for electrogenic potential of candidate algal strains. Furthermore, the results show that algal NADPH oxidases are important for superoxide anion production and open avenues for optimizing the biological component of these devices.« less

Status of Serum and Salivary Levels of Superoxide Dismutase in Type 2 Diabetes Mellitus with Oral Manifestations: A Case Control Study.

PubMed

Madi, Medhini; Babu, Subhas; Kumari, Suchetha; Shetty, Shishir; Achalli, Sonika; Madiyal, Ananya; Bhat, Manohar

2016-11-01

Type 2 Diabetes Mellitus is a very well known metabolic disorder that has reached epidemic proportions worldwide. Evidence suggests that oxidative stress increases in Diabetes Mellitus because of the excessive production of reactive oxygen species and an impaired antioxidant defence mechanism. This study estimated, compared and correlated the serum and salivary Superoxide dismutase levels in healthy subjects and subjects with Type 2 Diabetes Mellitus having oral manifestations. In this study, serum and salivary Superoxide dismutase levels were estimated in 45 healthy subjects and 45 patients with Type 2 Diabetes Mellitus with oral manifestations. The mean serum and salivary Superoxide dismutase levels were significantly decreased in subjects with Type 2 Diabetes Mellitus with oral manifestations compared to the healthy subjects. Positive correlation in both healthy and diabetics was observed between serum and salivary samples. This study highlights that the abnormally high levels of oxidative stress in diabetics coupled with simultaneous decline in antioxidant defence mechanism results in complications in Diabetes mellitus. Thus exploring saliva for antioxidant markers that accurately reflect the redox status of the body is worthwhile.

Effects of traditional medical herbs "minor bupleurum decoction" on the non-specific immune responses of white shrimp (Litopenaeus vannamei).

PubMed

Wu, Yu-Sheng; Lee, Meng-Chou; Huang, Cheng-Ting; Kung, Tzu-Chi; Huang, Chih-Yang; Nan, Fan-Hua

2017-05-01

This study is investigating the effect of minor bupleurum decoction (Xiao-Chai-Hu decoction) on the non-specific immune response of white shrimp (Litopenaeus vannamei). To determine prophenoloxidase activity (proPO), reactive oxygen species production (ROS), superoxide anion production (O 2 - ), nitric oxide production (NO), phagocytic rate (PR), phagocytic index (PI), superoxide dismutase activity (SOD), total haemocyte count (THC) and differential haemocyte count (DHC). In this experiment, treating with different dosages (0, 0.25, 0.5 and, 1%) of minor bupleurum decoction to detect immune parameters on day 0, 1, 2, 4, 7, 14, 21 and 28. Result is shown that 0.25% treatment significantly enhanced the superoxide dismutase (SOD) activity and, 0.25 and 1% treatment significantly increased the ROS production, nitric oxide (NO) production and phagocytic rate (PR) moreover, 0.5 and 1% treatment induced the proPO activity and superoxide anion (O 2 - ) production. Evidence exactly indicated that minor bupleurum decoction is able to enhance the non-specific immunity responses of white shrimp via in vivo examination. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Lipid peroxidation and the system of antioxidant protection in rats following a 13-day space flight on the Kosmos-1887 biosatellite].

PubMed

Markin, A A; Delenian, N V

1992-01-01

After a 13-day space mission, in the rats flown on Cosmos-1887 biosatellite the parameters of lipid peroxidation and antioxidant defense system--the contents of diene conjugates, malonic dialdehyde, Schiff bases, tocopherol, total antioxidant activity (in blood plasma only), antioxidant enzyme activity (in tissues only)--superoxide dismutase, catalase, glutathio peroxidase, glutathio reductase have been measured in the blood plasma, myocardium, skeletal muscles and liver. The liver level of diene conjugates, Schiff bases and tocopherol decreased, and an activity of superoxide dismutase and catalase increased. In the skeletal muscles there was an elevation of diene conjugate contents followed by the decreases in malonic dialdehyde and superoxide dismutase activity. In rat myocardium, superoxide dismutase activity and tocopherol levels increased significantly. In the blood plasma the levels of tocopherol, malonic dialdehyde and total antioxidant activity were elevated. It is concluded that the observed changes in lipid peroxidation developed probably in response to an effect of the last dynamic stage of space flight and during re-adapting to the Earth environments.

Developmental and environmental regulation of the Nicotiana plumbaginifolia cytosolic Cu/Zn-superoxide dismutase promoter in transgenic tobacco.

PubMed Central

Hérouart, D; Van Montagu, M; Inzé, D

1994-01-01

Superoxide dismutases (SODs) play a key role in the cellular defense against reactive oxygen species. To study the transcriptional regulation at the cellular level, the promoter of the Nicotiana plumbaginifolia cytosolic gene encoding Cu/ZnSOD (SODCc) was fused to the beta-glucuronidase (GUS) reporter gene (gusA) and analyzed in transgenic tobacco plants. The promoter was highly active in vascular bundles of leaves and stems, where it is confined to phloem cells. In flowers, GUS activity was detected in ovules and pollen grains, in pigmented tissues of petals, and in vascular tissue of ovaries and anthers. In response to treatment with the superoxide-generating herbicide paraquat, very strong GUS staining was observed in photosynthetically active cells of leaves and in some epidermal root cells of seedlings. The expression of the SODCc-gusA was also induced in seedlings after heat shock and chilling and after treatment with sulfhydryl antioxidants such as reduced glutathione and cysteine. It is postulated that SODCc expression is directly linked to a cell-specific production of excess superoxide radicals in the cytosol. PMID:8165260

Developmental and environmental regulation of the Nicotiana plumbaginifolia cytosolic Cu/Zn-superoxide dismutase promoter in transgenic tobacco.

PubMed

Hérouart, D; Van Montagu, M; Inzé, D

1994-03-01

Superoxide dismutases (SODs) play a key role in the cellular defense against reactive oxygen species. To study the transcriptional regulation at the cellular level, the promoter of the Nicotiana plumbaginifolia cytosolic gene encoding Cu/ZnSOD (SODCc) was fused to the beta-glucuronidase (GUS) reporter gene (gusA) and analyzed in transgenic tobacco plants. The promoter was highly active in vascular bundles of leaves and stems, where it is confined to phloem cells. In flowers, GUS activity was detected in ovules and pollen grains, in pigmented tissues of petals, and in vascular tissue of ovaries and anthers. In response to treatment with the superoxide-generating herbicide paraquat, very strong GUS staining was observed in photosynthetically active cells of leaves and in some epidermal root cells of seedlings. The expression of the SODCc-gusA was also induced in seedlings after heat shock and chilling and after treatment with sulfhydryl antioxidants such as reduced glutathione and cysteine. It is postulated that SODCc expression is directly linked to a cell-specific production of excess superoxide radicals in the cytosol.

Changes in oxidative stress intensity in blood of tumor-bearing rats following different modes of administration of rhenium-platinum system.

PubMed

Shamelashvili, K L; Shtemenko, N I; Leus, L V; Babiy, S O; Shtemenko, O V

2016-01-01

Effects of the different modes of administration of dichlorotetra-μ-isobutyratodirhenium(ІІІ) – І – (in water solution, liposomes, nanoliposomes and together with cisplatin – in the rhenium-platinum system) on the intensity of lipid peroxidation (LP) in blood plasma and the activity of the erythrocyte antioxidant enzymes were investigated on the model of tumor growth. A decrease in the concentration of TBA-active substances caused by dirhenium compounds was shown to be independent of the administration mode and the extent of the tumor growth inhibition. I was four-times more effective in inhibition of the LP burst than any known antioxidant. I induced the increasing activity of erythrocyte superoxide dismutase and decreasing activity of catalase. In vitro experiments with native superoxide dismutase, the interaction of І with following activation of the active center of the enzyme was confirmed and the superoxide dismutase activity of І was shown, that may contribute to the enhancement of the enzyme activity in vivo. The cluster rhenium compounds may be promising nontoxic potent antioxidants capable of deactivating superoxide radicals.

Superoxide dismutating molecules rescue the toxic effects of PINK1 and parkin loss.

PubMed

Biosa, Alice; Sanchez-Martinez, Alvaro; Filograna, Roberta; Terriente-Felix, Ana; Alam, Sarah M; Beltramini, Mariano; Bubacco, Luigi; Bisaglia, Marco; Whitworth, Alexander J

2018-05-01

Reactive oxygen species exert important functions in regulating several cellular signalling pathways. However, an excessive accumulation of reactive oxygen species can perturb the redox homeostasis leading to oxidative stress, a condition which has been associated to many neurodegenerative disorders. Accordingly, alterations in the redox state of cells and mitochondrial homeostasis are established hallmarks in both familial and sporadic Parkinson's disease cases. PINK1 and Parkin are two genes which account for a large fraction of autosomal recessive early-onset forms of Parkinson's disease and are now firmly associated to both mitochondria and redox homeostasis. In this study we explored the hypothesis that superoxide anions participate in the generation of the Parkin and PINK1 associated phenotypic effect by testing the capacity of endogenous and exogenous superoxide dismutating molecules to rescue the toxic effects induced by loss of PINK1 or Parkin, in both cellular and fly models. Our results demonstrate the positive effect of an increased level of superoxide dismutase proteins on the pathological phenotypes, both in vitro and in vivo. A more pronounced effectiveness for mitochondrial SOD2 activity points to the superoxide radicals generated in the mitochondrial matrix as the prime suspect in the definition of the observed phenotypes. Moreover, we also demonstrate the efficacy of a SOD-mimetic compound, M40403, to partially ameliorate PINK1/Parkin phenotypes in vitro and in vivo. These results support the further exploration of SOD-mimetic compounds as a therapeutic strategy against Parkinson's disease.

Angiotensin II type 1 receptor blockers prevent tumor necrosis factor-alpha-mediated endothelial nitric oxide synthase reduction and superoxide production in human umbilical vein endothelial cells.

PubMed

Kataoka, Hiroki; Murakami, Ryuichiro; Numaguchi, Yasushi; Okumura, Kenji; Murohara, Toyoaki

2010-06-25

Decrease in endothelial nitric oxide synthase (eNOS) expression is one of the adverse outcomes of endothelial dysfunction. Tumor necrosis factor-alpha (TNF-alpha) is known to decrease eNOS expression and is an important mediator of endothelial dysfunction. We hypothesized that an angiotensin II type 1 (AT1) receptor blocker would improve endothelial function via not only inhibition of the angiotensin II signaling but also inhibition of the TNF-alpha-mediated signaling. Therefore we investigated whether an AT1 receptor blocker would restore the TNF-alpha-induced decrease in eNOS expression in cultured human umbilical vein endothelial cells (HUVEC). Pretreatment of HUVEC with an antioxidant (superoxide dismutase, alpha-tocopherol) or AT1 receptor blockers (olmesartan or candesartan) restored the TNF-alpha-dependent reduction of eNOS. The AT1 receptor blocker decreased the TNF-alpha-dependent increase of 8-isoprostane. The superoxide dismutase activities in HUVEC were stable during AT1 receptor blocker treatment, and the AT1 receptor blocker did not scavenge superoxide directly. The AT1 receptor blocker also decreased TNF-alpha-induced phosphorylation of I kappaB alpha and cell death. These results suggest that AT1 receptor blockers are able to ameliorate TNF-alpha-dependent eNOS reduction or cell injury by inhibiting superoxide production or nuclear factor-kappaB activation. (c) 2010 Elsevier B.V. All rights reserved.

Immunolocalization of antioxidant enzymes in high-pressure frozen root and stem nodules of Sesbania rostrata.

PubMed

Rubio, Maria C; Becana, Manuel; Kanematsu, Sumio; Ushimaru, Takashi; James, Euan K

2009-01-01

The activities and localizations of superoxide dismutases (SODs) were compared in root and stem nodules of the semi-aquatic legume Sesbania rostrata using gel-activity assays and immunogold labelling, respectively. Nodules were fixed by high-pressure freezing and dehydrated by freeze substitution. Stem nodules showed more total and specific SOD activities than root nodules because of the presence of chloroplastic CuZnSOD. Most of the total SOD activity of stem and root nodules resulted from 'cytosolic' CuZnSOD, localized in the cytoplasm and chromatin, and from MnSOD in the bacteroids and in the mitochondria of vascular tissue. FeSOD was present in nodule plastids and in leaf chloroplasts, and was found to be associated with chromatin. Superoxide production was detected histochemically in the vascular bundles and in the infected tissue of stem and root nodules, whereas peroxide accumulation was observed in the cortical cell walls and intercellular spaces, as well as within the infection threads of both nodule types. These data suggest a role of CuZnSOD and FeSOD in protecting nuclear DNA from reactive oxygen species and/or in modulating gene activity. The enhanced levels of CuZnSOD, MnSOD and superoxide production in vascular bundle cells are consistent with a role of CuZnSOD and superoxide in the lignification of xylem vessels, but also suggest additional functions in coping with superoxide production by the high respiratory activity of parenchyma cells.

Simple Biological Systems for Assessing the Activity of Superoxide Dismutase Mimics

PubMed Central

Tovmasyan, Artak; Reboucas, Julio S.

2014-01-01

Abstract Significance: Half a century of research provided unambiguous proof that superoxide and species derived from it—reactive oxygen species (ROS)—play a central role in many diseases and degenerative processes. This stimulated the search for pharmaceutical agents that are capable of preventing oxidative damage, and methods of assessing their therapeutic potential. Recent Advances: The limitations of superoxide dismutase (SOD) as a therapeutic tool directed attention to small molecules, SOD mimics, that are capable of catalytically scavenging superoxide. Several groups of compounds, based on either metal complexes, including metalloporphyrins, metallocorroles, Mn(II) cyclic polyamines, and Mn(III) salen derivatives, or non-metal based compounds, such as fullerenes, nitrones, and nitroxides, have been developed and studied in vitro and in vivo. Very few entered clinical trials. Critical Issues and Future Directions: Development of SOD mimics requires in-depth understanding of their mechanisms of biological action. Elucidation of both molecular features, essential for efficient ROS-scavenging in vivo, and factors limiting the potential side effects requires biologically relevant and, at the same time, relatively simple testing systems. This review discuses the advantages and limitations of genetically engineered SOD-deficient unicellular organisms, Escherichia coli and Saccharomyces cerevisiae as tools for investigating the efficacy and mechanisms of biological actions of SOD mimics. These simple systems allow the scrutiny of the minimal requirements for a functional SOD mimic: the association of a high catalytic activity for superoxide dismutation, low toxicity, and an efficient cellular uptake/biodistribution. Antioxid. Redox Signal. 20, 2416–2436. PMID:23964890

Superoxide constricts rat pulmonary arteries via Rho-kinase-mediated Ca2+ sensitization

PubMed Central

Shaifta, Yasin; Connolly, Michelle; Drndarski, Svetlana; Noah, Anthony; Pourmahram, Ghazaleh E.; Becker, Silke; Aaronson, Philip I.; Ward, Jeremy P.T.

2018-01-01

Reactive oxygen species play a key role in vascular disease, pulmonary hypertension, and hypoxic pulmonary vasoconstriction. We investigated contractile responses, intracellular Ca2+ ([Ca2+]i), Rho-kinase translocation, and phosphorylation of the regulatory subunit of myosin phosphatase (MYPT-1) and of myosin light chain (MLC20) in response to LY83583, a generator of superoxide anion, in small intrapulmonary arteries (IPA) of rat. LY83583 caused concentration-dependent constrictions in IPA and greatly enhanced submaximal PGF2α-mediated preconstriction. In small femoral or mesenteric arteries of rat, LY83583 alone was without effect, but it relaxed a PGF2α-mediated preconstriction. Constrictions in IPA were inhibited by superoxide dismutase and tempol, but not catalase, and were endothelium and guanylate cyclase independent. Constrictions were also inhibited by the Rho-kinase inhibitor Y27632 and the Src-family kinase inhibitor SU6656. LY83583 did not raise [Ca2+]i, but caused a Y27632-sensitive constriction in α-toxin-permeabilized IPA. LY83583 triggered translocation of Rho-kinase from the nucleus to the cytosol in pulmonary artery smooth muscle cells and enhanced phosphorylation of MYPT-1 at Thr-855 and of MLC20 at Ser-19 in IPA. This enhancement was inhibited by superoxide dismutase and abolished by Y27632. Hydrogen peroxide did not activate Rho-kinase. We conclude that in rat small pulmonary artery, superoxide triggers Rho-kinase-mediated Ca2+ sensitization and vasoconstriction independent of hydrogen peroxide. PMID:19103285

The effect of alpha-lipoic acid on mitochondrial superoxide and glucocorticoid-induced hypertension.

PubMed

Ong, Sharon L H; Vohra, Harpreet; Zhang, Yi; Sutton, Matthew; Whitworth, Judith A

2013-01-01

To examine the effect of alpha-lipoic acid, an antioxidant with mitochondrial superoxide inhibitory properties, on adrenocorticotrophic hormone- (ACTH-HT) and dexamethasone-induced hypertensions (DEX-HT) in rats and if any antihypertensive effect is mediated via mitochondrial superoxide inhibition. In a prevention study, rats received ground food or alpha-lipoic-acid-laced food (10 mg/rat/day) for 15 nights. Saline, adrenocorticotrophic hormone (ACTH, 0.2 mg/kg/day), or dexamethasone (DEX, 10  μ g/rat/day) was injected subcutaneously from day 5 to day 11. In a reversal study, rats received alpha-lipoic-acid-laced food 4 days after commencement of saline or DEX. Tail-cuff systolic blood pressure (SBP) was measured second daily. Kidney mitochondrial superoxide was examined using (MitoSOX) Red (MitoSOX) via flow cytometry. SBP was increased by ACTH (P < 0.0005) and DEX (P < 0.0005). Alpha-lipoic acid alone did not alter SBP. With alpha-lipoic acid pretreatment, SBP was increased by ACTH (P' < 0.005) but not by DEX. Alpha-lipoic partially prevented ACTH-HT (P' < 0.0005) and fully prevented DEX-HT (P' < 0.0005) but failed to reverse DEX-HT. ACTH and DEX did not increase MitoSOX signal. In ACTH-hypertensive rats, high-dose alpha-lipoic acid (100 mg/rat/day) did not decrease SBP further but raised MitoSOX signal (P < 0.001), suggesting prooxidant activity. Glucocorticoid-induced hypertension in rats is prevented by alpha-lipoic acid via mechanisms other than mitochondrial superoxide reduction.

Isolation and characterization of Cu/Zn-superoxide dismutase in Fasciola gigantica.

PubMed

Lalrinkima, H; Raina, O K; Chandra, Dinesh; Jacob, Siju Susan; Bauri, R K; Chandra, Subhash; Yadav, H S; Singh, M N; Rialch, A; Varghese, A; Banerjee, P S; Kaur, Navneet; Sharma, Arvind

2015-01-01

A full-length complementary DNA (cDNA) encoding Cu/Zn-superoxide dismutase was isolated from Fasciola gigantica that on nucleotide sequencing showed a close homology (98.9%) with Cu/Zn-superoxide dismutase (SOD) of the temperate liver fluke, F. hepatica. Expression of the gene was found in all the three developmental stages of the parasite viz. adult, newly excysted juvenile and metacercaria at transcriptional level by reverse transcription-polymerase chain reaction (RT-PCR) and at the protein level by Western blotting. F. gigantica Cu/Zn-SOD cDNA was cloned and expressed in Escherichia coli. Enzyme activity of the recombinant protein was determined by nitroblue tetrazolium (NBT)-polyacrylamide gel electrophoresis (PAGE) and this activity was inactivated by hydrogen peroxide but not by sodium azide, indicating that the recombinant protein is Cu/Zn-SOD. The enzyme activity was relatively stable at a broad pH range of pH 4.0-10.0. Native Cu/Zn-superoxide dismutase protein was detected in the somatic extract and excretory-secretory products of the adult F. gigantica by Western blotting. NBT-PAGE showed a single Cu/Zn-SOD present in the somatic extract while three SODs are released ex vivo by the adult parasite. The recombinant superoxide dismutase did not react with the serum from buffaloes infected with F. gigantica. The role of this enzyme in defense by the parasite against the host reactive oxygen species is discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Acute effect of sidestream cigarette smoke extract on vascular endothelial function.

PubMed

Argacha, J F; Fontaine, D; Adamopoulos, D; Ajose, A; van de Borne, P; Fontaine, J; Berkenboom, G

2008-09-01

Acute exposure to passive smoking adversely affects vascular function by promoting oxidative stress and endothelial dysfunction. However, it is not known whether tobacco sidestream (SS) smoke has a greater deleterious effect on the endothelium than non-tobacco SS smoke and whether these effects are related to nicotinic endothelial stimulation. To test these hypotheses, endothelial-dependent relaxation and superoxide anion production were assessed in isolated rat aortas incubated with tobacco SS smoke, non-tobacco SS smoke, or pure nicotine. Tobacco SS smoke decreased the maximal relaxation to acetylcholine (Ach) from 79 +/- 6% to 57 +/- 7.3% (% inhibition of phenylephrine-induced plateau, P < 0.001) and increased superoxide anion production from 31 +/- 9.7 to 116 +/- 24 count/10 sec/mg (P < 0.01, lucigenin-enhanced chemiluminescence technique). The non-tobacco SS smoke extract had no significant effect on the response to Ach but increased superoxide anion production in the aortic wall to 133 +/- 2 count/10 sec/mg (P < 0.001). Furthermore, concentration-response curves to Ach and superoxide production remained unaltered with nicotine (0.001, 0.01, or 0.1 mM). In conclusion, despite similar increases in vascular wall superoxide production with tobacco and non-tobacco SS smoke, only the tobacco SS smoke extracts affected endothelium-dependent vasorelaxation. Nicotine alone does not reproduce the effects seen with tobacco SS smoke, suggesting that the acute endothelial toxicity of passive smoking cannot simply be ascribed to a nicotine-dependent mechanism.

Reduction of paraquat-induced renal cytotoxicity by manganese and copper complexes of EGTA and EHPG.

PubMed

Samai, Mohamed; Hague, Theresa; Naughton, Declan P; Gard, Paul R; Chatterjee, Prabal K

2008-02-15

Superoxide anion generation plays an important role in the development of paraquat toxicity. Although superoxide dismutase mimetics (SODm) have provided protection against organ injury involving generation of superoxide anions, they often suffer problems, e.g., regarding their bioavailability or potential pro-oxidant activity. The aim here was to investigate and compare the therapeutic potential of two novel SODm, manganese(II) and copper(II) complexes of the calcium chelator ethylenebis(oxyethylenenitrilo)tetraacetic acid (EGTA) and of the contrast agent ethylenebis(hydroxyphenylglycine) (EHPG), against paraquat-induced renal toxicity in vitro. Incubation of renal NRK-52E cells with paraquat (1 mM) for 24 h produced submaximal, yet significant, reduction in cellular viability and cell death and produced significant increases in superoxide anion and hydroxyl radical generation. Manganese and copper complexes of EGTA (10-100 microM) and EHPG (30-100 microM) reduced paraquat-induced renal cell toxicity and reduced superoxide anion and hydroxyl radical generation significantly. Manganese complexes displayed greater efficacy than copper complexes and, at equivalent concentrations, manganese complexed with EHPG provided the greatest protection. Furthermore, these metal complexes did not interfere with the uptake of [methyl-(14)C]paraquat into NRK-52E cells, suggesting that they provided protection against paraquat cytotoxicity via intracellular mechanisms. These complexes did not display cytotoxicity at the concentrations examined. Together, these results suggest that manganese and copper complexes of EGTA and EHPG, and especially the manganese-EHPG complex, could provide benefit against paraquat nephrotoxicity.

NADPH oxidase activation contributes to native low-density lipoprotein-induced proliferation of human aortic smooth muscle cells.

PubMed

Park, Il Hwan; Hwang, Hye Mi; Jeon, Byeong Hwa; Kwon, Hyung-Joo; Hoe, Kwang Lae; Kim, Young Myeong; Ryoo, Sungwoo

2015-06-12

Elevated plasma concentration of native low-density lipoprotein (nLDL) is associated with vascular smooth muscle cell (VSMC) activation and cardiovascular disease. We investigated the mechanisms of superoxide generation and its contribution to pathophysiological cell proliferation in response to nLDL stimulation. Lucigenin-induced chemiluminescence was used to measure nLDL-induced superoxide production in human aortic smooth muscle cells (hAoSMCs). Superoxide production was increased by nicotinamide adenine dinucleotide phosphate (NADPH) and decreased by NADPH oxidase inhibitors in nLDL-stimulated hAoSMC and hAoSMC homogenates, as well as in prepared membrane fractions. Extracellular signal-regulated kinase 1/2 (Erk1/2), protein kinase C-θ (PKCθ) and protein kinase C-β (PKCβ) were phosphorylated and maximally activated within 3 min of nLDL stimulation. Phosphorylated Erk1/2 mitogen-activated protein kinase, PKCθ and PKCβ stimulated interactions between p47phox and p22phox; these interactions were prevented by MEK and PKC inhibitors (PD98059 and calphostin C, respectively). These inhibitors decreased nLDL-dependent superoxide production and blocked translocation of p47phox to the membrane, as shown by epifluorescence imaging and cellular fractionation experiments. Proliferation assays showed that a small interfering RNA against p47phox, as well as superoxide scavenger and NADPH oxidase inhibitors, blocked nLDL-induced hAoSMC proliferation. The nLDL stimulation in deendothelialized aortic rings from C57BL/6J mice increased dihydroethidine fluorescence and induced p47phox translocation that was blocked by PD98059 or calphostin C. Isolated aortic SMCs from p47phox(-/-) mice (mAoSMCs) did not respond to nLDL stimulation. Furthermore, NADPH oxidase 1 (Nox1) was responsible for superoxide generation and cell proliferation in nLDL-stimulated hAoSMCs. These data demonstrated that NADPH oxidase activation contributed to cell proliferation in nLDL-stimulated hAoSMCs.

Unraveling the role of animal heme peroxidases in superoxide mediated Mn oxide formation

NASA Astrophysics Data System (ADS)

Learman, D. R.; Hansel, C. M.

2013-12-01

Manganese(III,IV) oxides are important in the environment as they can impact the fate of a broad range of nutrients (e.g. carbon and phosphate) and contaminates (e.g. lead and chromium). Bacteria play a valuable role in the production of Mn oxides, yet the mechanisms and physiological reasons remain unclear. Roseobacter sp. AzwK-3b, an organism within the abundant and ubiquitous Roseobacter clade, has recently been shown to oxidize Mn(II) via a novel pathway that involves enzymatic extracellular superoxide production. However, in reactions with only Mn(II) and abiotically generated superoxide, we find superoxide alone is not enough to produce Mn(III,IV) oxides. Scavenging of the byproduct hydrogen peroxide (via the addition of catalase) is required to generate Mn oxides via abiotic reaction of Mn(II) with superoxide. Thus, R. AzwK-3b must produce superoxide and also scavenge hydrogen peroxide to form Mn oxides. Further, in-gel Mn(II) oxidation assay revealed a protein band that could generate Mn oxides in the presence of soluble Mn(II). This Mn(II)-oxidizing protein band was excised from the gel and the peptides identified via mass spectrometry. An animal heme peroxidase (AHP) was the predominant protein found in this band. This protein is homologous to the AHPs previously implicated as a Mn(II)-oxidizing enzyme within the Alphaproteobacteria, Erythrobacter SD-21 and Aurantimonas manganoxydans strain SI85-9A1. Currently, protein expression of the AHPs in R. AzwK-3b is being examined to determine if expression is correlated with Mn(II) concentration or oxidative stress. Our data suggests that AHPs do not directly oxidize Mn(II) but rather plays a role in scavenging hydrogen peroxide and/or producing an organic Mn(III) ligand that complexes Mn(III) and likely aids in Mn oxide precipitation.

Designing Superoxide-Generating Quantum Dots for Selective Light-Activated Nanotherapy

NASA Astrophysics Data System (ADS)

Goodman, Samuel M.; Levy, Max; Li, Fei-Fei; Ding, Yuchen; Courtney, Colleen M.; Chowdhury, Partha P.; Erbse, Annette; Chatterjee, Anushree; Nagpal, Prashant

2018-03-01

The rapid emergence of superbugs or multi-drug resistant (MDR) organisms has prompted a search for novel antibiotics, beyond traditional small-molecule therapies. Nanotherapeutics are being investigated as alternatives, and recently superoxide-generating quantum dots (QDs) have been shown as important candidates for selective light-activated therapy and potentiating existing antibiotics against MDR superbugs. Their therapeutic action is selective, can be tailored by simply changing their quantum-confined conduction-valence bands and their alignment with different redox half-reactions, and hence their ability to generate specific radical species in biological media. Here, we show the design of superoxide-generating QDs using optimal QD material and size well matched to superoxide redox potential, charged ligands to modulate their uptake in cells and selective redox interventions, and core/shell structures to improve their stability for therapeutic action. We show that cadmium telluride (CdTe) QDs with conduction band position at -0.5V with respect to Normal Hydrogen Electron (NHE) and visible 2.4 eV bandgap generate a large flux of selective superoxide radicals, thereby demonstrating the most effective light-activated therapy. Although the positively charged QDs demonstrate large cellular uptake, they bind indiscriminately to cell surfaces and cause non-selective cell death, while negatively charged and zwitterionic QD ligands reduce the uptake and allow selective therapeutic action via interaction with redox species. The stability of designed QDs in biologically-relevant media increases with the formation of core-shell QD structures, but an appropriate design of core-shell structures is needed to minimize any reduction in charge injection efficiency to adsorbed oxygen molecules (to form superoxide) and maintain similar quantitative generation of tailored redox species, as measured using electron paramagnetic resonance (EPR) spectroscopy and electrochemical impedance spectroscopy. Using these findings, we demonstrate the rational design of QDs as selective therapeutic kills more than 99% of priority class I pathogens, thus providing an effective therapy against MDR superbugs.

Multiconfigurational and DFT analyses of the electromeric formulation and UV-vis absorption spectra of the superoxide adduct of ferrous superoxide reductase.

PubMed

Attia, Amr A A; Cioloboc, Daniela; Lupan, Alexandru; Silaghi-Dumitrescu, Radu

2016-12-01

The putative initial adduct of ferrous superoxide reductase (SOR) with superoxide has been alternatively formulated as ferric-peroxo or ferrous-superoxo. The ~600-nm UV-vis absorption band proposed to be assigned to this adduct (either as sole intermediate in the SOR catalytic cycle, or as one of the two intermediates) has recently been interpreted as due to a ligand-to-metal charge transfer, involving thiolate and superoxide in a ferrous complex, contrary to an alternative assignment as a predominantly cysteine thiolate-to-ferric charge transfer in a ferric-peroxo electromer. In an attempt to clarify the electromeric formulation of this adduct, we report a computational study using a multiconfigurational complete active space self-consistent field (MC-CASSCF) wave function approach as well as modelling the UV-vis absorption spectra with time-dependent density functional theory (TD-DFT). The MC-CASSCF calculations disclose a weak interaction between iron and the dioxygenic ligand and a dominant configuration with an essentially ferrous-superoxo character. The computed UV-vis absorption spectra reveal a marked dependence on the choice of density functional - both in terms of location of bands and in terms of orbital contributors. For the main band in the visible region, besides the recently reported thiolate-to-superoxide charge transfer, a more salient, and less functional-dependent, feature is a thiolate-to-ferric iron charge transfer, consistent with a ferric-peroxo electromer. By contrast, the computed UV-vis spectra of a ferric-hydroperoxo SOR model match distinctly better (and with no qualitative dependence on the DFT methodology) the 600-nm band as due to a mainly thiolate-to-ferric character - supporting the assignment of the SOR "600-nm intermediate" as a S=5/2 ferric-hydroperoxo species. Copyright © 2016 Elsevier Inc. All rights reserved.

Rotenone-stimulated superoxide release from mitochondrial complex I acutely augments L-type Ca2+ current in A7r5 aortic smooth muscle cells

PubMed Central

Dhagia, Vidhi; Lakhkar, Anand; Patel, Dhara; Wolin, Michael S.; Gupte, Sachin A.

2016-01-01

Voltage-gated L-type Ca2+ current (ICa,L) induces contraction of arterial smooth muscle cells (ASMCs), and ICa,L is increased by H2O2 in ASMCs. Superoxide released from the mitochondrial respiratory chain (MRC) is dismutated to H2O2. We studied whether superoxide per se acutely modulates ICa,L in ASMCs using cultured A7r5 cells derived from rat aorta. Rotenone is a toxin that inhibits complex I of the MRC and increases mitochondrial superoxide release. The superoxide content of mitochondria was estimated using mitochondrial-specific MitoSOX and HPLC methods, and was shown to be increased by a brief exposure to 10 μM rotenone. ICa,L was recorded with 5 mM BAPTA in the pipette solution. Rotenone administration (10 nM to 10 μM) resulted in a greater ICa,L increase in a dose-dependent manner to a maximum of 22.1% at 10 μM for 1 min, which gradually decreased to 9% after 5 min. The rotenone-induced ICa,L increase was associated with a shift in the current-voltage relationship (I-V) to a hyperpolarizing direction. DTT administration resulted in a 17.9% increase in ICa,L without a negative shift in I–V, and rotenone produced an additional increase with a shift. H2O2 (0.3 mM) inhibited ICa,L by 13%, and additional rotenone induced an increase with a negative shift. Sustained treatment with Tempol (4-hydroxy tempo) led to a significant ICa,L increase but it inhibited the rotenone-induced increase. Staurosporine, a broad-spectrum protein kinase inhibitor, partially inhibited ICa,L and completely suppressed the rotenone-induced increase. Superoxide released from mitochondria affected protein kinases and resulted in stronger ICa,L preceding its dismutation to H2O2. The removal of nitric oxide is a likely mechanism for the increase in ICa,L. PMID:26873970

Designing Superoxide-Generating Quantum Dots for Selective Light-Activated Nanotherapy.

PubMed

Goodman, Samuel M; Levy, Max; Li, Fei-Fei; Ding, Yuchen; Courtney, Colleen M; Chowdhury, Partha P; Erbse, Annette; Chatterjee, Anushree; Nagpal, Prashant

2018-01-01

The rapid emergence of superbugs, or multi-drug resistant (MDR) organisms, has prompted a search for novel antibiotics, beyond traditional small-molecule therapies. Nanotherapeutics are being investigated as alternatives, and recently superoxide-generating quantum dots (QDs) have been shown as important candidates for selective light-activated therapy, while also potentiating existing antibiotics against MDR superbugs. Their therapeutic action is selective, can be tailored by simply changing their quantum-confined conduction-valence band (CB-VB) positions and alignment with different redox half-reactions-and hence their ability to generate specific radical species in biological media. Here, we show the design of superoxide-generating QDs using optimal QD material and size well-matched to superoxide redox potential, charged ligands to modulate their uptake in cells and selective redox interventions, and core/shell structures to improve their stability for therapeutic action. We show that cadmium telluride (CdTe) QDs with conduction band (CB) position at -0.5 V with respect to Normal Hydrogen Electron (NHE) and visible 2.4 eV bandgap generate a large flux of selective superoxide radicals, thereby demonstrating the effective light-activated therapy. Although the positively charged QDs demonstrate large cellular uptake, they bind indiscriminately to cell surfaces and cause non-selective cell death, while negatively charged and zwitterionic QD ligands reduce the uptake and allow selective therapeutic action via interaction with redox species. The stability of designed QDs in biologically-relevant media increases with the formation of core-shell QD structures, but an appropriate design of core-shell structures is needed to minimize any reduction in charge injection efficiency to adsorbed oxygen molecules (to form superoxide) and maintain similar quantitative generation of tailored redox species, as measured using electron paramagnetic resonance (EPR) spectroscopy and electrochemical impedance spectroscopy (EIS). Using these findings, we demonstrate the rational design of QDs as selective therapeutic to kill more than 99% of a priority class I pathogen, thus providing an effective therapy against MDR superbugs.

Production of Superoxide in Bacteria Is Stress- and Cell State-Dependent: A Gating-Optimized Flow Cytometry Method that Minimizes ROS Measurement Artifacts with Fluorescent Dyes.

PubMed

McBee, Megan E; Chionh, Yok H; Sharaf, Mariam L; Ho, Peiying; Cai, Maggie W L; Dedon, Peter C

2017-01-01

The role of reactive oxygen species (ROS) in microbial metabolism and stress response has emerged as a major theme in microbiology and infectious disease. Reactive fluorescent dyes have the potential to advance the study of ROS in the complex intracellular environment, especially for high-content and high-throughput analyses. However, current dye-based approaches to measuring intracellular ROS have the potential for significant artifacts. Here, we describe a robust platform for flow cytometric quantification of ROS in bacteria using fluorescent dyes, with ROS measurements in 10s-of-1000s of individual cells under a variety of conditions. False positives and variability among sample types (e.g., bacterial species, stress conditions) are reduced with a flexible four-step gating scheme that accounts for side- and forward-scattered light (morphological changes), background fluorescence, DNA content, and dye uptake to identify cells producing ROS. Using CellROX Green dye with Escherichia coli, Mycobacterium smegmatis , and Mycobacterium bovis BCG as diverse model bacteria, we show that (1) the generation of a quantifiable CellROX Green signal for superoxide, but not hydrogen peroxide-induced hydroxyl radicals, validates this dye as a superoxide detector; (2) the level of dye-detectable superoxide does not correlate with cytotoxicity or antibiotic sensitivity; (3) the non-replicating, antibiotic tolerant state of nutrient-deprived mycobacteria is associated with high levels of superoxide; and (4) antibiotic-induced production of superoxide is idiosyncratic with regard to both the species and the physiological state of the bacteria. We also show that the gating method is applicable to other fluorescent indicator dyes, such as the 5-carboxyfluorescein diacetate acetoxymethyl ester and 5-cyano-2,3-ditolyl tetrazolium chloride for cellular esterase and reductive respiratory activities, respectively. These results demonstrate that properly controlled flow cytometry coupled with fluorescent probes provides precise and accurate quantitative analysis of ROS generation and metabolic changes in stressed bacteria.

Antioxidant Effect of Melatonin on the Functional Activity of Colostral Phagocytes in Diabetic Women

PubMed Central

Fagundes, Danny L. G.; Calderon, Iracema M. P.; França, Eduardo L.

2013-01-01

Melatonin is involved in a number of physiological and oxidative processes, including functional regulation in human milk. The present study investigated the mechanisms of action of melatonin and its effects on the functional activity of colostral phagocytes in diabetic women. Colostrum samples were collected from normoglycemic (N = 38) and diabetic (N = 38) women. We determined melatonin concentration, superoxide release, bactericidal activity and intracellular Ca2+ release by colostral phagocytes treated or not with 8-(Diethylamino) octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8) and incubated with melatonin and its precursor (N-acetyl-serotonin-NAS), antagonist (luzindole) and agonist (chloromelatonin-CMLT). Melatonin concentration was higher in colostrum samples from hyperglycemic than normoglycemic mothers. Melatonin stimulated superoxide release by colostral phagocytes from normoglycemic but not hyperglycemic women. NAS increased superoxide, irrespective of glycemic status, whereas CMTL increased superoxide only in cells from the normoglycemic group. Phagocytic activity in colostrum increased significantly in the presence of melatonin, NAS and CMLT, irrespective of glycemic status. The bactericidal activity of colostral phagocytes against enterophatogenic Escherichia coli (EPEC) increased in the presence of melatonin or NAS in the normoglycemic group, but not in the hyperglycemic group. Luzindole blocked melatonin action on colostrum phagocytes. Phagocytes from the normoglycemic group treated with melatonin exhibited an increase in intracellular Ca2+ release. Phagocytes treated with TMB-8 (intracellular Ca2+ inhibitor) decreased superoxide, bactericidal activity and intracellular Ca2+ release in both groups. The results obtained suggest an interactive effect of glucose metabolism and melatonin on colostral phagocytes. In colostral phagocytes from normoglycemic mothers, melatonin likely increases the ability of colostrum to protect against EPEC and other infections. In diabetic mothers, because maternal hyperglycemia modifies the functional activity of colostrum phagocytes, melatonin effects are likely limited to anti-inflammatory processes, with low superoxide release and bactericidal activity. PMID:23437270

Atrial myocardial nox2 containing NADPH oxidase activity contribution to oxidative stress in mitral regurgitation: potential mechanism for atrial remodeling.

PubMed

Chang, Jen-Ping; Chen, Mien-Cheng; Liu, Wen-Hao; Yang, Cheng-Hsu; Chen, Chien-Jen; Chen, Yung-Lung; Pan, Kuo-Li; Tsai, Tzu-Hsien; Chang, Hsueh-Wen

2011-01-01

Oxidative stress is linked with several cardiovascular diseases. However, the NADPH oxidase activity in severe mitral regurgitation patients with and without atrial fibrillation has not yet been explored. This study involved 16 adult patients (eight patients with persistent atrial fibrillation and eight with sinus rhythm) with severe mitral and moderate-to-severe tricuspid regurgitation and five control patients without mitral and tricuspid disease. Atrial tissues of the right and left atrial appendages were obtained during surgery. Superoxide anion production was measured by lucigenin-enhanced chemiluminescence, and the expression of nox2 containing NADPH oxidase mRNA was measured by quantitative real-time RT-PCR. Additionally, immunohistochemical study was performed. NADPH-stimulated superoxide release was significantly higher than basal superoxide production from right [5671.9±3498.7 vs. 232.7±70.0 relative light units per second per milligram of protein (RLU s(-1) mg protein(-1)), P=.008) and left atrial homogenates (6475.1±1890.8 vs. 229.0±79.6 RLU s(-1) mg protein(-1), P=.008) in atrial fibrillation patients. The NADPH-stimulated superoxide release from right atrial homogenates was also significantly higher than basal superoxide production in sinus patients (6809.1±1327.1 vs. 244.2±65.5 RLU s(-1) mg protein(-1), P=.008). Additionally, there was a borderline significant correlation between NADPH-stimulated superoxide production from left atrial homogenates and left atrial sizes (r=0.683, P=.062) in atrial fibrillation patients. Membrane-bound nox2 containing NADPH oxidase mRNA expression was increased and was similar in both the atrial fibrillation patients and sinus patients. The NADPH-stimulated superoxide production in right atrial homogenates in control atrial samples was 1863.7±137.2 RLU s(-1) mg protein(-1). Immunohistochemical study demonstrated increased expression of nox2 in myocytes with moderate-to-severe myolysis and hypertrophy. Results of this study demonstrate that membrane-bound nox2 containing NADPH oxidase activity and expression in the atrial myocardium is increased in patients with severe mitral regurgitation, possibly contributing to atrial remodeling in this clinical setting. Copyright © 2011 Elsevier Inc. All rights reserved.

Phosphate, not superoxide dismutase, facilitates electron transfer from ferrous salts to cytochrome c.

PubMed

Beyer, W F; Fridovich, I

1991-02-15

Peterson and Eaton (1989, Biochem. Biophys. Res. Commun. 165, 164-167) reported that the copper- and zinc-containing, but not the manganese-containing, superoxide dismutase catalyzes the reduction of cytochrome c by ferrous salts. This activity, erroneously attributed to the enzyme, is now shown to have been due to inorganic phosphate.

Glucose-6-Phosphate-Dehydrogenase Is Also Increased in Erythrocytes from Adolescents with Down Syndrome

ERIC Educational Resources Information Center

Ordonez, Francisco J.; Rosety-Plaza, Manuel; Rosety-Rodriguez, Manuel

2006-01-01

For some time it has been claimed that trisomic cells are more sensitive to oxidative stress since there is an imbalance in hydrogen peroxide metabolism due to an increase in superoxide dismutase (SOD) catalytic activity. We designed the present study to assess activity levels of antioxidant enzymes [superoxide dismutase (SOD), glutathione…

Copper-Zinc Superoxide Dismutase: A Unique Biological "Ligand" for Bioinorganic Studies.

ERIC Educational Resources Information Center

Valentine, Joan Selverstone; de Freitas, Duarte Mota

1985-01-01

Discusses superoxide dismutase (SOD) research and the properties of copper, zinc (Cu, Zn)-SOD. Emphasizes the controversy concerning the role of Cu,Zn-SOD and other SOD enzymes as protective agents in reactions involving dioxygen metabolism, and the properties of Cu, Zn-SOD that make it an interesting biological ligand for physical studies of…

Preliminary neutron diffraction analysis of challenging human manganese superoxide dismutase crystals

DOE PAGES

Azadmanesh, Jahaun; Trickel, Scott R.; Weiss, Kevin L.; ...

2017-03-29

Superoxide dismutases (SODs) are enzymes that protect against oxidative stress by dismutation of superoxide into oxygen and hydrogen peroxide through cyclic reduction and oxidation of the active-site metal. The complete enzymatic mechanisms of SODs are unknown since data on the positions of hydrogen are limited. Here, we present, methods for large crystal growth and neutron data collection of human manganese SOD (MnSOD) using perdeuteration and the MaNDi beamline at Oak Ridge National Laboratory. Furthermore, The crystal from which the human MnSOD data set was obtained is the crystal with the largest unit-cell edge (240 Å) from which data have beenmore » collectedvianeutron diffraction to sufficient resolution (2.30 Å) where hydrogen positions can be observed.« less

Preliminary neutron diffraction analysis of challenging human manganese superoxide dismutase crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azadmanesh, Jahaun; Trickel, Scott R.; Weiss, Kevin L.

Superoxide dismutases (SODs) are enzymes that protect against oxidative stress by dismutation of superoxide into oxygen and hydrogen peroxide through cyclic reduction and oxidation of the active-site metal. The complete enzymatic mechanisms of SODs are unknown since data on the positions of hydrogen are limited. Here, we present, methods for large crystal growth and neutron data collection of human manganese SOD (MnSOD) using perdeuteration and the MaNDi beamline at Oak Ridge National Laboratory. Furthermore, The crystal from which the human MnSOD data set was obtained is the crystal with the largest unit-cell edge (240 Å) from which data have beenmore » collectedvianeutron diffraction to sufficient resolution (2.30 Å) where hydrogen positions can be observed.« less

Rotenone Activates Phagocyte NADPH Oxidase through Binding to Its Membrane Subunit gp91phox

PubMed Central

Zhou, Hui; Zhang, Feng; Chen, Shih-heng; Zhang, Dan; Wilson, Belinda; Hong, Jau-shyong; Gao, Hui-Ming

2011-01-01

Rotenone, a widely used pesticide, reproduces Parkinsonism in rodents and associates with increased risk for Parkinson’s disease. We previously reported rotenone increased superoxide production through stimulating microglial phagocyte NADPH oxidase (PHOX). The present study identified a novel mechanism by which rotenone activates PHOX. Ligand-binding assay revealed that rotenone directly bound to membrane gp91phox, the catalytic subunit of PHOX; such binding was inhibited by diphenyleneiodonium, a PHOX inhibitor with a binding site on gp91phox. Functional studies showed both membrane and cytosolic subunits were required for rotenone-induced superoxide production in cell-free systems, intact phagocytes, and COS7 cells transfected with membrane subunits (gp91phox/p22phox) and cytosolic subunits (p67phox and p47phox). Rotenone-elicited extracellular superoxide release in p47phox-deficient macrophages suggested rotenone enabled to activate PHOX through a p47phox-independent mechanism. Increased membrane translocation of p67phox, elevated binding of p67phox to rotenone-treated membrane fractions, and co-immunoprecipitation of p67phox and gp91phox in rotenone-treated wild-type and p47phox-deficient macrophages indicated p67phox played a critical role in rotenone-induced PHOX activation via its direct interaction with gp91phox. Rac1, a Rho-like small GTPase, enhanced p67phox-gp91phox interaction; Rac1 inhibition decreased rotenone-elicited superoxide release. In conclusion, rotenone directly interacted with gp91phox; such an interaction triggered membrane translocation of p67phox, leading to PHOX activation and superoxide production. PMID:22094225

Superoxide Production by a Manganese-Oxidizing Bacterium Facilitates Iodide Oxidation

PubMed Central

Li, Hsiu-Ping; Daniel, Benjamin; Creeley, Danielle; Grandbois, Russell; Zhang, Saijin; Xu, Chen; Ho, Yi-Fang; Schwehr, Kathy A.; Kaplan, Daniel I.; Santschi, Peter H.; Hansel, Colleen M.

2014-01-01

The release of radioactive iodine (i.e., iodine-129 and iodine-131) from nuclear reprocessing facilities is a potential threat to human health. The fate and transport of iodine are determined primarily by its redox status, but processes that affect iodine oxidation states in the environment are poorly characterized. Given the difficulty in removing electrons from iodide (I−), naturally occurring iodide oxidation processes require strong oxidants, such as Mn oxides or microbial enzymes. In this study, we examine iodide oxidation by a marine bacterium, Roseobacter sp. AzwK-3b, which promotes Mn(II) oxidation by catalyzing the production of extracellular superoxide (O2−). In the absence of Mn2+, Roseobacter sp. AzwK-3b cultures oxidized ∼90% of the provided iodide (10 μM) within 6 days, whereas in the presence of Mn(II), iodide oxidation occurred only after Mn(IV) formation ceased. Iodide oxidation was not observed during incubations in spent medium or with whole cells under anaerobic conditions or following heat treatment (boiling). Furthermore, iodide oxidation was significantly inhibited in the presence of superoxide dismutase and diphenylene iodonium (a general inhibitor of NADH oxidoreductases). In contrast, the addition of exogenous NADH enhanced iodide oxidation. Taken together, the results indicate that iodide oxidation was mediated primarily by extracellular superoxide generated by Roseobacter sp. AzwK-3b and not by the Mn oxides formed by this organism. Considering that extracellular superoxide formation is a widespread phenomenon among marine and terrestrial bacteria, this could represent an important pathway for iodide oxidation in some environments. PMID:24561582

Superoxide production by a manganese-oxidizing bacterium facilitates iodide oxidation.

PubMed

Li, Hsiu-Ping; Daniel, Benjamin; Creeley, Danielle; Grandbois, Russell; Zhang, Saijin; Xu, Chen; Ho, Yi-Fang; Schwehr, Kathy A; Kaplan, Daniel I; Santschi, Peter H; Hansel, Colleen M; Yeager, Chris M

2014-05-01

The release of radioactive iodine (i.e., iodine-129 and iodine-131) from nuclear reprocessing facilities is a potential threat to human health. The fate and transport of iodine are determined primarily by its redox status, but processes that affect iodine oxidation states in the environment are poorly characterized. Given the difficulty in removing electrons from iodide (I(-)), naturally occurring iodide oxidation processes require strong oxidants, such as Mn oxides or microbial enzymes. In this study, we examine iodide oxidation by a marine bacterium, Roseobacter sp. AzwK-3b, which promotes Mn(II) oxidation by catalyzing the production of extracellular superoxide (O2(-)). In the absence of Mn(2+), Roseobacter sp. AzwK-3b cultures oxidized ∼90% of the provided iodide (10 μM) within 6 days, whereas in the presence of Mn(II), iodide oxidation occurred only after Mn(IV) formation ceased. Iodide oxidation was not observed during incubations in spent medium or with whole cells under anaerobic conditions or following heat treatment (boiling). Furthermore, iodide oxidation was significantly inhibited in the presence of superoxide dismutase and diphenylene iodonium (a general inhibitor of NADH oxidoreductases). In contrast, the addition of exogenous NADH enhanced iodide oxidation. Taken together, the results indicate that iodide oxidation was mediated primarily by extracellular superoxide generated by Roseobacter sp. AzwK-3b and not by the Mn oxides formed by this organism. Considering that extracellular superoxide formation is a widespread phenomenon among marine and terrestrial bacteria, this could represent an important pathway for iodide oxidation in some environments.

FcγR-induced production of superoxide and inflammatory cytokines is differentially regulated by SHIP through its influence on PI3K and/or Ras/Erk pathways

PubMed Central

Ganesan, Latha P.; Joshi, Trupti; Fang, Huiqing; Kutala, Vijay Kumar; Roda, Julie; Trotta, Rossana; Lehman, Amy; Kuppusamy, Periannan; Byrd, John C.; Carson, William E.; Caligiuri, Michael A.; Tridandapani, Susheela

2006-01-01

Phagocytosis of IgG-coated particles via FcγR is accompanied by the generation of superoxide and inflammatory cytokines, which can cause collateral tissue damage in the absence of regulation. Molecular mechanisms regulating these phagocytosis-associated events are not known. SHIP is an inositol phosphatase that downregulates PI3K-mediated activation events. Here, we have examined the role of SHIP in FcγR-induced production of superoxide and inflammatory cytokines. We report that primary SHIP-deficient bone marrow macrophages produce elevated levels of superoxide upon FcγR clustering. Analysis of the molecular mechanism revealed that SHIP regulates upstream Rac-GTP binding, an obligatory event for superoxide production. Likewise, SHIP-deficient macrophages displayed enhanced IL-1β and IL-6 production in response to FcγR clustering. Interestingly, whereas IL-6 production required activation of both PI3K and Ras/Erk pathways, IL-1β production was dependent only on Ras/Erk activation, suggesting that SHIP may also regulate the Ras/Erk pathway in macrophages. Consistently, SHIP-deficient macrophages displayed enhanced activation of Erk upon FcγR clustering. Inhibition of Ras/Erk or PI3K suppressed the enhanced production of IL-6 in SHIP-deficient macrophages. In contrast, inhibition of Ras/Erk, but not PI3K, suppressed IL-1β production in these cells. Together, these data demonstrate that SHIP regulates phagocytosis-associated events through the inhibition of PI3K and Ras/Erk pathways. PMID:16543474

The Superoxide Reductase from the Early Diverging Eukaryote Giardia Intestinalis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cabelli, D.E.; Testa, F.; Mastronicola, D.

2011-10-15

Unlike superoxide dismutases (SODs), superoxidereductases (SORs) eliminate superoxide anion (O{sub 2}{sup {sm_bullet}-}) not through its dismutation, but via reduction to hydrogen peroxide (H{sub 2}O{sub 2}) in the presence of an electron donor. The microaerobic protist Giardia intestinalis, responsible for a common intestinal disease in humans, though lacking SOD and other canonical reactive oxygen species-detoxifying systems, is among the very few eukaryotes encoding a SOR yet identified. In this study, the recombinant SOR from Giardia (SOR{sub Gi}) was purified and characterized by pulse radiolysis and stopped-flow spectrophotometry. The protein, isolated in the reduced state, after oxidation by superoxide or hexachloroiridate(IV), yieldsmore » a resting species (T{sub final}) with Fe{sup 3+} ligated to glutamate or hydroxide depending on pH (apparent pK{sub a} = 8.7). Although showing negligible SOD activity, reduced SOR{sub Gi} reacts with O{sub 2}{sup {sm_bullet}-} with a pH-independent second-order rate constant k{sub 1} = 1.0 x 10{sup 9} M{sup -1} s{sup -1} and yields the ferric-(hydro)peroxo intermediate T{sub 1}; this in turn rapidly decays to the T{sub final} state with pH-dependent rates, without populating other detectable intermediates. Immunoblotting assays show that SOR{sub Gi} is expressed in the disease-causing trophozoite of Giardia. We propose that the superoxide-scavenging activity of SOR in Giardia may promote the survival of this air-sensitive parasite in the fairly aerobic proximal human small intestine during infection.« less

The Effect of Alpha-Lipoic Acid on Mitochondrial Superoxide and Glucocorticoid-Induced Hypertension

PubMed Central

Ong, Sharon L. H.; Vohra, Harpreet; Zhang, Yi; Sutton, Matthew; Whitworth, Judith A.

2013-01-01

Aims. To examine the effect of alpha-lipoic acid, an antioxidant with mitochondrial superoxide inhibitory properties, on adrenocorticotrophic hormone- (ACTH-HT) and dexamethasone-induced hypertensions (DEX-HT) in rats and if any antihypertensive effect is mediated via mitochondrial superoxide inhibition. Methods. In a prevention study, rats received ground food or alpha-lipoic-acid-laced food (10 mg/rat/day) for 15 nights. Saline, adrenocorticotrophic hormone (ACTH, 0.2 mg/kg/day), or dexamethasone (DEX, 10 μg/rat/day) was injected subcutaneously from day 5 to day 11. In a reversal study, rats received alpha-lipoic-acid-laced food 4 days after commencement of saline or DEX. Tail-cuff systolic blood pressure (SBP) was measured second daily. Kidney mitochondrial superoxide was examined using (MitoSOX) Red (MitoSOX) via flow cytometry. Results. SBP was increased by ACTH (P < 0.0005) and DEX (P < 0.0005). Alpha-lipoic acid alone did not alter SBP. With alpha-lipoic acid pretreatment, SBP was increased by ACTH (P′ < 0.005) but not by DEX. Alpha-lipoic partially prevented ACTH-HT (P′ < 0.0005) and fully prevented DEX-HT (P′ < 0.0005) but failed to reverse DEX-HT. ACTH and DEX did not increase MitoSOX signal. In ACTH-hypertensive rats, high-dose alpha-lipoic acid (100 mg/rat/day) did not decrease SBP further but raised MitoSOX signal (P < 0.001), suggesting prooxidant activity. Conclusion. Glucocorticoid-induced hypertension in rats is prevented by alpha-lipoic acid via mechanisms other than mitochondrial superoxide reduction. PMID:23533693

Superoxide reaction with tyrosyl radicals generates para-hydroperoxy and para-hydroxy derivatives of tyrosine.

PubMed

Möller, Matías N; Hatch, Duane M; Kim, Hye-Young H; Porter, Ned A

2012-10-10

Tyrosine-derived hydroperoxides are formed in peptides and proteins exposed to enzymatic or cellular sources of superoxide and oxidizing species as a result of the nearly diffusion-limited reaction between tyrosyl radical and superoxide. However, the structure of these products, which informs their reactivity in biology, has not been unequivocally established. We report here the complete characterization of the products formed in the addition of superoxide, generated from xanthine oxidase, to several peptide-derived tyrosyl radicals, formed from horseradish peroxidase. RP-HPLC, LC-MS, and NMR experiments indicate that the primary stable products of superoxide addition to tyrosyl radical are para-hydroperoxide derivatives (para relative to the position of the OH in tyrosine) that can be reduced to the corresponding para-alcohol. In the case of glycyl-tyrosine, a stable 3-(1-hydroperoxy-4-oxocyclohexa-2,5-dien-1-yl)-L-alanine was formed. In tyrosyl-glycine and Leu-enkephalin, which have N-terminal tyrosines, bicyclic indolic para-hydroperoxide derivatives were formed ((2S,3aR,7aR)-3a-hydroperoxy-6-oxo-2,3,3a,6,7,7a-hexahydro-1H-indole-2-carboxylic acid) by the conjugate addition of the free amine to the cyclohexadienone. It was also found that significant amounts of the para-OH derivative were generated from the hydroxyl radical, formed on exposure of tyrosine-containing peptides to Fenton conditions. The para-OOH and para-OH derivatives are much more reactive than other tyrosine oxidation products and may play important roles in physiology and disease.

AMELIORATION OF ETHANOL-INDUCED DYSMORPHOGENESIS IN RODENT EMBRYOS IN VITRO USING ADENOVIRAL-MEDIATED EXPRESSION OF CU,ZN-SUPEROXIDE DISMUTASE (SOD1) OR MN-SUPEROXIDE DISMUTASE (SOD2)

EPA Science Inventory

Ethanol produces dysmorphogenesis in offspring when pregnant animals are exposed in vivo (Chaudhuri 2000; Hannigan and Armant, 2000) and by direct exposure of neurulation staged embryos to ethanol in vitro (Kotch et al., 1995; Hunter et al., 1994 ; Thompson and Folb, 1982). The a...

Mononuclear nonheme iron(III) complexes that show superoxide dismutase-like activity and antioxidant effects against menadione-mediated oxidative stress.

PubMed

Hitomi, Yutaka; Iwamoto, Yuji; Kashida, Akihiro; Kodera, Masahito

2015-05-21

This communication describes the superoxide dismutase (SOD)-like activity of mononuclear iron(III) complexes with pentadentate monocarboxylamido ligands. The SOD activity can be controlled by the electronic nature of the substituent group on the ligand. The nitro-substituted complex showed clear cytoprotective activity against menadione-mediated oxidative stress in cultured cells.

Effect of quercitrin gallate on zymosan A-induced peroxynitrite production in macrophages.

PubMed

Kim, Byung Hak; Cho, Sung-Min; Chang, Yoon Sook; Han, Sang Bae; Kim, Youngsoo

2007-06-01

We previously isolated quercetin 3-O-beta-(2"-galloyl)-rhamnopyranoside (QGR), a quercitrin gallate, from aerial parts of Persicaria lapathifolia (Polygonaceae) to prevent superoxide produc tion in monocytes from venous blood of healthy human donors. In this study, effects of QGR and its building moieties (quercitrin, quercetin and gallic acid) on the production of peroxyni trite, a coupling oxidant between superoxide and nitric oxide (NO) radicals, were investigated in zymosan A-stimulated macrophages RAW 264.7. The QGR, quercitrin and quercetin inhib ited peroxynitrite production in dose-dependent manners with IC50 values of 2.1 microM, 24.5 microM and 5.1 microM, respectively, but gallic acid even at 100 microM was inactive. QGR also inhibited both zymosan A- and phorbol 12-myristate 13-acetate-induced superoxide productions with IC50 values of 3.2 microM and 4.7 microM, respectively. However, QGR affected neither zymosan A-induced NO production nor inducible NO synthase synthesis. Taken together, QGR could inhibit peroxynitrite production by blocking superoxide production without affecting NO production. Finally, this study could provide a pharmacological potential of QGR in the oxidative stress-implicated disorders.

Sustained contraction and endothelial dysfunction induced by reactive oxygen species in porcine coronary artery.

PubMed

Ishihara, Yasuhiro; Sekine, Masaya; Hatano, Ai; Shimamoto, Norio

2008-09-01

A combination of purine and xanthine oxidase (XOD) dose-dependently elicited sustained contraction of porcine coronary arterial rings and resulted in increased concentrations of superoxide anions and hydrogen peroxide. These contractile responses appeared, with a delay, after the application of purine and XOD, used as a reactive oxygen species (ROS)-generating system. Coronary arteries precontracted with prostaglandin F(2alpha) failed to relax in response to substance P after exposing the arterial preparation to this ROS-generating system. The contractile response of the coronary artery to the ROS-generating system was almost completely inhibited by catalase (130 U/ml), and was partially inhibited by superoxide dismutase (60 U/ml), or mannitol (30 mM). A voltage-dependent L-type Ca(2+) channel antagonist, nicardipine, had no effect on contraction. Dysfunction of endothelial cells was completely prevented by catalase, but not by superoxide dismutase or mannitol. These results suggest that superoxide anions, hydrogen peroxide and hydroxyl radicals might be involved in eliciting sustained, delayed-onset coronary artery contraction, which is not related to L-type Ca(2+) channels. They also suggest that hydrogen peroxide might play a major role in endothelial dysfunction of the porcine coronary artery.

Targeting the NO/superoxide ratio in adipose tissue: relevance to obesity and diabetes management.

PubMed

Jankovic, Aleksandra; Korac, Aleksandra; Buzadzic, Biljana; Stancic, Ana; Otasevic, Vesna; Ferdinandy, Péter; Daiber, Andreas; Korac, Bato

2017-06-01

Insulin sensitivity and metabolic homeostasis depend on the capacity of adipose tissue to take up and utilize excess glucose and fatty acids. The key aspects that determine the fuel-buffering capacity of adipose tissue depend on the physiological levels of the small redox molecule, nitric oxide (NO). In addition to impairment of NO synthesis, excessive formation of the superoxide anion (О 2 •- ) in adipose tissue may be an important interfering factor diverting the signalling of NO and other reactive oxygen and nitrogen species in obesity, resulting in metabolic dysfunction of adipose tissue over time. Besides its role in relief from superoxide burst, enhanced NO signalling may be responsible for the therapeutic benefits of different superoxide dismutase mimetics, in obesity and experimental diabetes models. This review summarizes the role of NO in adipose tissue and highlights the effects of NO/О 2 •- ratio 'teetering' as a promising pharmacological target in the metabolic syndrome. This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc. © 2016 The British Pharmacological Society.

Chronopharmacological effects of growth hormone on the executive function and oxidative stress response in rats.

PubMed

Ferrari, Carlos K B; França, Eduardo L; Monteiro, Luciane A; Santos, Bruno L; Pereira-Junior, Alfredo; Honorio-França, Adenilda C

2017-01-01

To investigate the chronopharmacological effects of growth hormone on executive function and the oxidative stress response in rats. Fifty male Wistar rats (36-40 weeks old) had ad libitum access to water and food and were separated into four groups: diurnal control, nocturnal control, diurnal GH-treated, and nocturnal GH-treated animals. Levels of Cu, Zn superoxide dismutase (Cu, Zn-SOD), and superoxide release by spleen macrophages were evaluated. For memory testing, adaptation and walking in an open field platform was used. GH-treated animals demonstrated better performance in exploratory and spatial open-field tests. The latency time in both GH-treated groups was significantly lower compared with the latency time of the control groups. The diurnal GH treatment did not stimulate superoxide release but increased the CuZn-SOD enzyme levels. The nocturnal GH treatment did not influence the superoxide release and CuZn-SOD concentration. GH treatment also resulted in heart atrophy and lung hypertrophy. Growth hormone treatment improved the performance of executive functions at the cost of oxidative stress triggering, and this effect was dependent on the circadian period of hormone administration. However, GH treatment caused damaging effects such as lung hypertrophy and heart atrophy.

Essential role of protein kinase C zeta in transducing a motility signal induced by superoxide and a chemotactic peptide, fMLP.

PubMed

Kuribayashi, Kageaki; Nakamura, Kiminori; Tanaka, Maki; Sato, Tsutomu; Kato, Junji; Sasaki, Katsunori; Takimoto, Rishu; Kogawa, Katsuhisa; Terui, Takeshi; Takayama, Tetsuji; Onuma, Takayuki; Matsunaga, Takuya; Niitsu, Yoshiro

2007-03-26

Under various pathological conditions, including infection, malignancy, and autoimmune diseases, tissues are incessantly exposed to reactive oxygen species produced by infiltrating inflammatory cells. We show augmentation of motility associated with morphological changes of human squamous carcinoma SASH1 cells, human peripheral monocytes (hPMs), and murine macrophage-like cell line J774.1 by superoxide stimulation. We also disclose that motility of hPMs and J774.1 induced by a chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine [fMLP]) was inhibited by superoxide dismutase or N-acetylcystein, indicating stimulation of motility by superoxide generated by fMLP stimulation. In these cells, protein kinase C (PKC) zeta was activated to phosphorylate RhoGDI-1, which liberated RhoGTPases, leading to their activation. These events were inhibited by dominant-negative PKCzeta in SASH1 cells, myristoylated PKCzeta peptides in hPMs and J774.1, or a specific inhibitor of RhoGTPase in SASH1, hPMs, and J774.1. These results suggest a new approach for manipulation of inflammation as well as tumor cell invasion by targeting this novel signaling pathway.

Essential role of protein kinase C ζ in transducing a motility signal induced by superoxide and a chemotactic peptide, fMLP

PubMed Central

Kuribayashi, Kageaki; Nakamura, Kiminori; Tanaka, Maki; Sato, Tsutomu; Kato, Junji; Sasaki, Katsunori; Takimoto, Rishu; Kogawa, Katsuhisa; Terui, Takeshi; Takayama, Tetsuji; Onuma, Takayuki; Matsunaga, Takuya; Niitsu, Yoshiro

2007-01-01

Under various pathological conditions, including infection, malignancy, and autoimmune diseases, tissues are incessantly exposed to reactive oxygen species produced by infiltrating inflammatory cells. We show augmentation of motility associated with morphological changes of human squamous carcinoma SASH1 cells, human peripheral monocytes (hPMs), and murine macrophage-like cell line J774.1 by superoxide stimulation. We also disclose that motility of hPMs and J774.1 induced by a chemotactic peptide (N-formyl-methionyl-leucyl-phenylalanine [fMLP]) was inhibited by superoxide dismutase or N-acetylcystein, indicating stimulation of motility by superoxide generated by fMLP stimulation. In these cells, protein kinase C (PKC) ζ was activated to phosphorylate RhoGDI-1, which liberated RhoGTPases, leading to their activation. These events were inhibited by dominant-negative PKCζ in SASH1 cells, myristoylated PKCζ peptides in hPMs and J774.1, or a specific inhibitor of RhoGTPase in SASH1, hPMs, and J774.1. These results suggest a new approach for manipulation of inflammation as well as tumor cell invasion by targeting this novel signaling pathway. PMID:17389234

Electron transport chain dysfunction by H(2)O (2) is linked to increased reactive oxygen species production and iron mobilization by lipoperoxidation: studies using Saccharomyces cerevisiae mitochondria.

PubMed

Cortés-Rojo, Christian; Estrada-Villagómez, Mirella; Calderón-Cortés, Elizabeth; Clemente-Guerrero, Mónica; Mejía-Zepeda, Ricardo; Boldogh, Istvan; Saavedra-Molina, Alfredo

2011-04-01

The mitochondrial electron transport chain (ETC) contains thiol groups (-SH) which are reversibly oxidized to modulate ETC function during H(2)O(2) overproduction. Since deleterious effects of H(2)O(2) are not limited to -SH oxidation, due to the formation of other H(2)O(2)-derived species, some processes like lipoperoxidation could enhance the effects of H(2)O(2) over ETC enzymes, disrupt their modulation by -SH oxidation and increase superoxide production. To verify this hypothesis, we tested the effects of H(2)O(2) on ETC activities, superoxide production and iron mobilization in mitochondria from lipoperoxidation-resistant native yeast and lipoperoxidation-sensitized yeast. Only complex III activity from lipoperoxidation-sensitive mitochondria exhibited a higher susceptibility to H(2)O(2) and increased superoxide production. The recovery of ETC activity by the thiol reductanct β-mercaptoethanol (BME) was also altered at complex III, and a role was attributed to lipoperoxidation, the latter being also responsible for iron release. A hypothetical model linking lipoperoxidation, increased complex III damage, superoxide production and iron release is given.

Extraction of superoxide dismutase, catalase, and carbonic anhydrase from stroma-free red blood cell hemolysate for the preparation of the nanobiotechnological complex of polyhemoglobin-superoxide dismutase-catalase-carbonic anhydrase.

PubMed

Guo, C; Gynn, M; Chang, T M S

2015-06-01

We report a novel method to simultaneously extract superoxide dismutase (SOD), catalase (CAT), and carbonic anhydrase (CA) from the same sample of red blood cells (RBCs). This avoids the need to use expensive commercial enzymes, thus enabling a cost-effective process for large-scale production of a nanobiotechnological polyHb-SOD-CAT-CA complex, with enhancement of all three red blood cell functions. An optimal concentration of phosphate buffer for ethanol-chloroform treatment results in good recovery of CAT, SOD, and CA after extraction. Different concentrations of the enzymes can be used to enhance the activity of polyHb-SOD-CAT-CA to 2, 4, or 6 times that of RBC.

Granulocyte Macrophage Colony-Stimulating Factor Alone Reduces Toxoplasma gondii Replication in Microglial Culture by Superoxide and Nitric Oxide, without IFN-γ production: A Preliminary Report.

PubMed

Pimenta, Tamirys Simão; Chaves, Natalie Ferreira; Drummond Rodrigues, Ana Paula; Picanço Diniz, Cristovam Wanderley; DaMatta, Renato Augusto; Picanço Diniz Junior, José Antônio

2018-06-07

In vitro studies have demonstrated that GM-CSF in combination with other stimulatory factors induces a microbicidal response that control T. gondii infection. We assessed whether GM-CSF alone can control T. gondiireplication in murine microglial cultures. Microglia were collected and cultured with or without GM-CSF and the half of each group was infected with T. gondii. We determined the T. gondii infectivity, cytokines levels, NO and superoxide detection.GM-CSF alone primes microglia, which after infection induces the production of TNF-α and IL-6, leading to NO and superoxide production, without any stimulus from IL-12p70 and IFN-γ. Copyright © 2018. Published by Elsevier Masson SAS.

Functional Activities and Immunohistochemical Distribution of Superoxide Dismutase in Normal, Dysplastic and Squamous Cell Carcinoma Oral Tissues

DTIC Science & Technology

2001-07-26

antioxidant enzymes: SOD, catalase ( CAT ), and glutathione peroxidase (GPO).2 ° SOD converts superoxide radical into hydrogen peroxide, while CAT and GPO convert...in endometriosis and adenomyosis. Fertility and Sterility 1999; 1:129-134. 45. Muse KE, Oberley TD, Sempf JM, Oberley LW. Immunolocalization of antioxidant enzymes in adult hamster kidney. Histochem J 1994;9:734-753. 43

Solution behavior of iron(III) and iron(II) porphyrins in DMSO and reaction with superoxide. Effect of neighboring positive charge on thermodynamics, kinetics and nature of iron-(su)peroxo product.

PubMed

Duerr, K; Troeppner, O; Olah, J; Li, J; Zahl, A; Drewello, T; Jux, N; Harvey, J N; Ivanović-Burmazović, I

2012-01-14

The solution behavior of iron(III) and iron(II) complexes of 5(4),10(4),15(4),20(4)-tetra-tert-butyl-5,10,15,20-tetraphenylporphyrin (H(2)tBuTPP) and the reaction with superoxide (KO(2)) in DMSO have been studied in detail. Applying temperature and pressure dependent NMR studies, the thermodynamics of the low-spin/high-spin equilibrium between bis- and mono-DMSO Fe(II) forms have been quantified (K(DMSO) = 0.082 ± 0.002 at 298.2 K, ΔH° = +36 ± 1 kJ mol(-1), ΔS° = +101 ± 4 J K(-1) mol(-1), ΔV° = +16 ± 2 cm(3) mol(-1)). This is a key activation step for substitution and inner-sphere electron transfer. The superoxide binding constant to the iron(II) form of the studied porphyrin complex was found to be (9 ± 0.5) × 10(3) M(-1), and does not change significantly in the presence of the externally added crown ether in DMSO (11 ± 4) × 10(3) M(-1). The rate constants for the superoxide binding (k(on) = (1.30 ± 0.01) × 10(5) M(-1) s(-1)) and release (k(off) = 11.6 ± 0.7 s(-1)) are not affected by the presence of the external crown ether in solution. The resulting iron(II)-superoxide adduct has been characterized (mass spectrometry, EPR, high-pressure UV/Vis spectroscopy) and upon controlled addition of a proton source it regenerates the starting iron(II) complex. Based on DFT calculations, the reaction product without neighboring positive charge has iron(II)-superoxo character in both high-spin side-on and low-spin end-on forms. The results are compared to those obtained for the analogous complex with covalently attached crown ether, and more general conclusions regarding the spin-state equilibrium of iron(II) porphyrins, their reaction with superoxide and the electronic structure of the product species are drawn.

Piper betle shows antioxidant activities, inhibits MCF-7 cell proliferation and increases activities of catalase and superoxide dismutase.

PubMed

Abrahim, Noor Nazirahanie; Kanthimathi, M S; Abdul-Aziz, Azlina

2012-11-15

Breast cancer is the most common form of cancer and the focus on finding chemotherapeutic agents have recently shifted to natural products. Piper betle is a medicinal plant with various biological activities. However, not much data is available on the anti-cancer effects of P. betle on breast cancer. Due to the current interest in the potential effects of antioxidants from natural products in breast cancer treatment, we investigated the antioxidant activities of the leaves of P. betle and its inhibitory effect on the proliferation of the breast cancer cell line, MCF-7. The leaves of P. betle were extracted with solvents of varying polarities (water, methanol, ethyl acetate and hexane) and their phenolic and flavonoid content were determined using colorimetric assays. Phenolic composition was characterized using HPLC. Antioxidant activities were measured using FRAP, DPPH, superoxide anion, nitric oxide and hyroxyl radical scavenging assays. Biological activities of the extracts were analysed using MTT assay and antioxidant enzyme (catalase, superoxide dismutase, glutathione peroxidase) assays in MCF-7 cells. Overall, the ethyl acetate extract showed the highest ferric reducing activity and radical scavenging activities against DPPH, superoxide anion and nitric oxide radicals. This extract also contained the highest phenolic content implying the potential contribution of phenolics towards the antioxidant activities. HPLC analyses revealed the presence of catechin, morin and quercetin in the leaves. The ethyl acetate extract also showed the highest inhibitory effect against the proliferation of MCF-7 cells (IC50=65 μg/ml). Treatment of MCF-7 cells with the plant extract increased activities of catalase and superoxide dismutase. Ethyl acetate is the optimal solvent for the extraction of compounds with antioxidant and anti-proliferative activities. The increased activities of catalase and superoxide dismutase in the treated cells could alter the antioxidant defense system, potentially contributing towards the anti-proliferative effect. There is great potential for the ethyl acetate extract of P. betle leaf as a source of natural antioxidants and to be developed as therapeutics in cancer treatment.

Piper betle shows antioxidant activities, inhibits MCF-7 cell proliferation and increases activities of catalase and superoxide dismutase

PubMed Central

2012-01-01

Background Breast cancer is the most common form of cancer and the focus on finding chemotherapeutic agents have recently shifted to natural products. Piper betle is a medicinal plant with various biological activities. However, not much data is available on the anti-cancer effects of P. betle on breast cancer. Due to the current interest in the potential effects of antioxidants from natural products in breast cancer treatment, we investigated the antioxidant activities of the leaves of P. betle and its inhibitory effect on the proliferation of the breast cancer cell line, MCF-7. Methods The leaves of P. betle were extracted with solvents of varying polarities (water, methanol, ethyl acetate and hexane) and their phenolic and flavonoid content were determined using colorimetric assays. Phenolic composition was characterized using HPLC. Antioxidant activities were measured using FRAP, DPPH, superoxide anion, nitric oxide and hyroxyl radical scavenging assays. Biological activities of the extracts were analysed using MTT assay and antioxidant enzyme (catalase, superoxide dismutase, glutathione peroxidase) assays in MCF-7 cells. Results Overall, the ethyl acetate extract showed the highest ferric reducing activity and radical scavenging activities against DPPH, superoxide anion and nitric oxide radicals. This extract also contained the highest phenolic content implying the potential contribution of phenolics towards the antioxidant activities. HPLC analyses revealed the presence of catechin, morin and quercetin in the leaves. The ethyl acetate extract also showed the highest inhibitory effect against the proliferation of MCF-7 cells (IC50=65 μg/ml). Treatment of MCF-7 cells with the plant extract increased activities of catalase and superoxide dismutase. Conclusions Ethyl acetate is the optimal solvent for the extraction of compounds with antioxidant and anti-proliferative activities. The increased activities of catalase and superoxide dismutase in the treated cells could alter the antioxidant defense system, potentially contributing towards the anti-proliferative effect. There is great potential for the ethyl acetate extract of P. betle leaf as a source of natural antioxidants and to be developed as therapeutics in cancer treatment. PMID:23153283

Chronic estradiol-17β exposure increases superoxide production in the rostral ventrolateral medulla and causes hypertension: reversal by resveratrol.

PubMed

Subramanian, Madhan; Balasubramanian, Priya; Garver, Hannah; Northcott, Carrie; Zhao, Huawei; Haywood, Joseph R; Fink, Gregory D; MohanKumar, Sheba M J; MohanKumar, P S

2011-06-01

Women are exposed to estrogen in several forms, such as oral contraceptive pills and hormone replacement therapy. Although estrogen was believed to be cardioprotective, lately, its beneficial effects are being questioned. Recent studies indicate that oxidative stress in the rostral ventrolateral medulla (RVLM) may play a role in the development of hypertension. Therefore, we hypothesized that chronic exposure to low levels of estradiol-17β (E(2)) leads to hypertension in adult-cycling female Sprague Dawley (SD) rats potentially through generation of superoxide in the RVLM. To test this hypothesis, young adult (3 or 4 mo old) female SD rats were either sham-implanted or implanted (subcutaneously) with slow-release E(2) pellets (20 ng/day) for 90 days. A group of control and E(2)-treated animals were fed lab chow or chow containing resveratrol (0.84 g/kg of chow), an antioxidant. Rats were implanted with telemeters to continuously monitor blood pressure (BP) and heart rate (HR). At the end of treatment, the RVLM was isolated for measurements of superoxide. E(2) treatment significantly increased mean arterial pressure (mmHg) and HR (beats/min) compared with sham rats (119.6 ± 0.8 vs. 105.1 ± 0.7 mmHg and 371.7 ± 1.5 vs. 354.4 ± 1.3 beats/min, respectively; P < 0.0001). Diastolic and systolic BP were significantly increased in E(2)-treated rats compared with control animals. Superoxide levels in the RVLM increased significantly in the E(2)-treated group (0.833 ± 0.11 nmol/min·mg) compared with control (0.532 ± 0.04 nmol/min·mg; P < 0.05). Treatment with resveratrol reversed the E(2)-induced increases in BP and superoxide levels in the RVLM. In conclusion, these findings support the hypothesis that chronic exposure to low levels of E(2) induces hypertension and increases superoxide levels in the RVLM and that this effect can be reversed by resveratrol treatment.

Real-time cytometric assay of nitric oxide and superoxide interaction in peripheral blood monocytes: A no-wash, no-lyse kinetic method.

PubMed

Balaguer, Susana; Diaz, Laura; Gomes, Angela; Herrera, Guadalupe; O'Connor, José-Enrique; Urios, Amparo; Felipo, Vicente; Montoliu, Carmina

2017-05-01

Nitric oxide (NO) and its related reactive nitrogen species (RNS) and reactive oxygen species (ROS) are crucial in monocyte responses against pathogens and also in inflammatory conditions. Central to both processes is the generation of the strong oxidant peroxynitrite (ONOO) by a fast reaction between NO and superoxide anion. ONOO is a biochemical junction for ROS- and RNS cytotoxicity and causes protein nitrosylation. Circulating by-products of protein nitrosylation are early biomarkers of inflammation-based conditions, including minimal hepatic encephalopathy in cirrhotic patients (Montoliu et al., Am J Gastroenterol 2011; 106:1629-1637). In this context, we have designed a novel no-wash, no-lyse real-time flow cytometry assay to detect and follow-up the NO- and superoxide-driven generation of ONOO in peripheral blood monocytes. Whole blood samples were stained with CD45 and CD14 antibodies plus one of a series of fluorescent probes sensitive to RNS, ROS, or glutathione, namely 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate, dihydrorhodamine 123, MitoSOX Red, dihydroethidium, and 5-chloromethylfluorescein diacetate. Samples were exposed sequentially to a NO donor and three different superoxide donors, and analyzed in real time by kinetic flow cytometry. Relevant kinetic descriptors, such as the rate of fluorescence change, were calculated from the kinetic plot. The generation of ONOO, which consumes both NO and superoxide, led to a decrease in the intensity of the cellular fluorescence of the probes sensitive to these molecules. This is a fast and simple assay that may be used to monitor the intracellular generation of ONOO in physiological, pathological, and pharmacological contexts. © 2015 International Clinical Cytometry Society. © 2015 International Clinical Cytometry Society.

Mitochondrial and Cytoplasmic ROS Have Opposing Effects on Lifespan

PubMed Central

Schaar, Claire E.; Dues, Dylan J.; Spielbauer, Katie K.; Machiela, Emily; Cooper, Jason F.; Senchuk, Megan; Hekimi, Siegfried; Van Raamsdonk, Jeremy M.

2015-01-01

Reactive oxygen species (ROS) are highly reactive, oxygen-containing molecules that can cause molecular damage within the cell. While the accumulation of ROS-mediated damage is widely believed to be one of the main causes of aging, ROS also act in signaling pathways. Recent work has demonstrated that increasing levels of superoxide, one form of ROS, through treatment with paraquat, results in increased lifespan. Interestingly, treatment with paraquat robustly increases the already long lifespan of the clk-1 mitochondrial mutant, but not other long-lived mitochondrial mutants such as isp-1 or nuo-6. To genetically dissect the subcellular compartment in which elevated ROS act to increase lifespan, we deleted individual superoxide dismutase (sod) genes in clk-1 mutants, which are sensitized to ROS. We find that only deletion of the primary mitochondrial sod gene, sod-2 results in increased lifespan in clk-1 worms. In contrast, deletion of either of the two cytoplasmic sod genes, sod-1 or sod-5, significantly decreases the lifespan of clk-1 worms. Further, we show that increasing mitochondrial superoxide levels through deletion of sod-2 or treatment with paraquat can still increase lifespan in clk-1;sod-1 double mutants, which live shorter than clk-1 worms. The fact that mitochondrial superoxide can increase lifespan in worms with a detrimental level of cytoplasmic superoxide demonstrates that ROS have a compartment specific effect on lifespan – elevated ROS in the mitochondria acts to increase lifespan, while elevated ROS in the cytoplasm decreases lifespan. This work also suggests that both ROS-dependent and ROS-independent mechanisms contribute to the longevity of clk-1 worms. PMID:25671321

Structural evidence for a copper-bound carbonate intermediate in the peroxidase and dismutase activities of superoxide dismutase.

PubMed

Strange, Richard W; Hough, Michael A; Antonyuk, Svetlana V; Hasnain, S Samar

2012-01-01

Copper-zinc superoxide dismutase (SOD) is of fundamental importance to our understanding of oxidative damage. Its primary function is catalysing the dismutation of superoxide to O(2) and H(2)O(2). SOD also reacts with H(2)O(2), leading to the formation of a strong copper-bound oxidant species that can either inactivate the enzyme or oxidise other substrates. In the presence of bicarbonate (or CO(2)) and H(2)O(2), this peroxidase activity is enhanced and produces the carbonate radical. This freely diffusible reactive oxygen species is proposed as the agent for oxidation of large substrates that are too bulky to enter the active site. Here, we provide direct structural evidence, from a 2.15 Å resolution crystal structure, of (bi)carbonate captured at the active site of reduced SOD, consistent with the view that a bound carbonate intermediate could be formed, producing a diffusible carbonate radical upon reoxidation of copper. The bound carbonate blocks direct access of substrates to Cu(I), suggesting that an adjunct to the accepted mechanism of SOD catalysed dismutation of superoxide operates, with Cu(I) oxidation by superoxide being driven via a proton-coupled electron transfer mechanism involving the bound carbonate rather than the solvent. Carbonate is captured in a different site when SOD is oxidised, being located in the active site channel adjacent to the catalytically important Arg143. This is the probable route of diffusion from the active site following reoxidation of the copper. In this position, the carbonate is poised for re-entry into the active site and binding to the reduced copper.

Structural Evidence for a Copper-Bound Carbonate Intermediate in the Peroxidase and Dismutase Activities of Superoxide Dismutase

PubMed Central

Strange, Richard W.; Hough, Michael A.; Antonyuk, Svetlana V.; Hasnain, S. Samar

2012-01-01

Copper-zinc superoxide dismutase (SOD) is of fundamental importance to our understanding of oxidative damage. Its primary function is catalysing the dismutation of superoxide to O2 and H2O2. SOD also reacts with H2O2, leading to the formation of a strong copper-bound oxidant species that can either inactivate the enzyme or oxidise other substrates. In the presence of bicarbonate (or CO2) and H2O2, this peroxidase activity is enhanced and produces the carbonate radical. This freely diffusible reactive oxygen species is proposed as the agent for oxidation of large substrates that are too bulky to enter the active site. Here, we provide direct structural evidence, from a 2.15 Å resolution crystal structure, of (bi)carbonate captured at the active site of reduced SOD, consistent with the view that a bound carbonate intermediate could be formed, producing a diffusible carbonate radical upon reoxidation of copper. The bound carbonate blocks direct access of substrates to Cu(I), suggesting that an adjunct to the accepted mechanism of SOD catalysed dismutation of superoxide operates, with Cu(I) oxidation by superoxide being driven via a proton-coupled electron transfer mechanism involving the bound carbonate rather than the solvent. Carbonate is captured in a different site when SOD is oxidised, being located in the active site channel adjacent to the catalytically important Arg143. This is the probable route of diffusion from the active site following reoxidation of the copper. In this position, the carbonate is poised for re-entry into the active site and binding to the reduced copper. PMID:22984565

Heme oxygenase attenuates angiotensin II-mediated superoxide production in cultured mouse thick ascending loop of Henle cells.

PubMed

Kelsen, Silvia; Patel, Bijal J; Parker, Lawson B; Vera, Trinity; Rimoldi, John M; Gadepalli, Rama S V; Drummond, Heather A; Stec, David E

2008-10-01

Heme oxygenase (HO)-1 induction can attenuate the development of angiotensin II (ANG II)-dependent hypertension. However, the mechanism by which HO-1 lowers blood pressure is not clear. The goal of this study was to test the hypothesis that induction of HO-1 can reduce the ANG II-mediated increase in superoxide production in cultured thick ascending loop of Henle (TALH) cells. Studies were performed on an immortalized cell line of mouse TALH (mTALH) cells. HO-1 was induced in cultured mTALH cells by treatment with cobalt protoporphyrin (CoPP, 10 microM) or hemin (50 microM) or by transfection with a plasmid containing the human HO-1 isoform. Treatment of mTALH cells with 10(-9) M ANG II increased dihydroethidium (DHE) fluorescence (an index of superoxide levels) from 35.5+/-5 to 136+/-18 relative fluorescence units (RFU)/microm2. Induction of HO-1 via CoPP, hemin, or overexpression of the human HO-1 isoform significantly reduced ANG II-induced DHE fluorescence to 64+/-5, 64+/-8, and 41+/-4 RFU/microm2, respectively. To determine which metabolite of HO-1 is responsible for reducing ANG II-mediated increases in superoxide production in mTALH cells, cells were preincubated with bilirubin or carbon monoxide (CO)-releasing molecule (CORM)-A1 (each at 100 microM) before exposure to ANG II. DHE fluorescence averaged 80+/-7 RFU/microm2 after incubation with ANG II and was significantly decreased to 55+/-7 and 53+/-4 RFU/microm2 after pretreatment with bilirubin and CORM-A1. These results demonstrate that induction of HO-1 in mTALH cells reduces the levels of ANG II-mediated superoxide production through the production of both bilirubin and CO.

Detection of Redox Imbalance in Normal Lymphocytes with Induced Mitochondrial Dysfunction - EPR Study.

PubMed

Georgieva, Ekaterina; Zhelev, Zhivko; Aoki, Ichio; Bakalova, Rumiana; Higashi, Tatsuya

2016-10-01

The present study describes a new approach for direct imaging of redox status in live cells using paramagnetic spin-probes, which allows evaluation of the level of oxidative stress due to overproduction of superoxide. The method is based on redox cycling of cell/mitochondria-penetrating nitroxide radicals (e.g. mito-TEMPO) and their electron-paramagnetic resonance (EPR) contrast, which makes them useful molecular sensors for analysis of redox status and oxidative stress in cells and tissues. Oxidative stress was induced in normal human lymphocytes by treatment with 2-methoxyestradiol and rotenone (ME/Rot) at different concentrations. This combination provokes mitochondrial dysfunction, which is accompanied by overproduction of superoxide. The EPR measurements were performed in dynamics on X-Band spectrometer after addition of mito-TEMPO to cell suspensions. The intensity of the EPR signal in untreated cells decreased significantly, which indicates a conversion of paramagnetic mito-TEMPO to its non-contrast diamagnetic form (hydroxylamine - mito-TEMPOH) due to reduction. In ME/Rot-treated cells, the signal decreased more slowly and to a lower level with increasing the concentration of ME/Rot. These data indicate an induction of oxidative stress in the cells in a concentration-dependent manner. A very good positive correlation between the intensity of EPR signal of mito-TEMPO and the intracellular level of superoxide was found, analyzed by conventional dihydroethidium test (R=0.9143, p<0.001). In conclusion, our study demonstrated that cell-penetrating paramagnetic spin-probes, such as mito-TEMPO, are valuable tools for EPR imaging of the superoxide level in live cells, as well as for EPR imaging of mitochondrial dysfunction and metabolic activity, accompanied by superoxide imbalance. Copyright© 2016 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

Activation of PPARδ prevents endothelial dysfunction induced by overexpression of amyloid-β precursor protein

PubMed Central

d'Uscio, Livius V.; Das, Pritam; Santhanam, Anantha V.R.; He, Tongrong; Younkin, Steven G.; Katusic, Zvonimir S.

2012-01-01

Aims Existing evidence suggests that amyloid-β precursor protein (APP) causes endothelial dysfunction and contributes to pathogenesis of atherosclerosis. In the present study, experiments were designed to: (1) determine the mechanisms underlying endothelial dysfunction and (2) define the effects of peroxisome proliferator-activated receptor delta (PPARδ) ligand on endothelial function in transgenic Tg2576 mice overexpressing mutated human APP. Methods and results Confocal microscopy and western blot analyses of wild-type mice aortas provided evidence that APP protein is mainly present in endothelial cells. Overexpression of APP significantly impaired endothelium-dependent relaxations to acetylcholine and phosphorylation of endothelial nitric oxide synthase at Ser1177 in aortas. HPLC analysis revealed that tetrahydrobiopterin (BH4) levels were reduced in Tg2576 mice aortas. This was caused by increased oxidation of BH4 and reduced expression and activity of GTP-cyclohydrolase I. Furthermore, gp91phox protein expression and superoxide anion production were increased in aortas of Tg2576 mice. This augmented superoxide formation was completely prevented by the NADPH oxidase inhibitor VAS2870. Expression of copper-/zinc-superoxide dismutase (Cu/ZnSOD) and extracellular SOD was downregulated. Treatment with PPARδ ligand GW501516 (2 mg/kg/day) for 14 days significantly increased BH4 bioavailability and improved endothelium-dependent relaxations in Tg2576 mice aortas. GW501516 also normalized protein expression of gp91phox and SODs, thereby reducing production of superoxide anion in the aortas. Conclusion Our results suggest that in APP transgenic mice loss of nitric oxide and increased oxidative stress are the major causes of endothelial dysfunction. The vascular protective effects of GW501516 in Tg2576 mice appear to be critically dependent on prevention of superoxide anion production. PMID:22886847

Activation of PPARδ prevents endothelial dysfunction induced by overexpression of amyloid-β precursor protein.

PubMed

d'Uscio, Livius V; Das, Pritam; Santhanam, Anantha V R; He, Tongrong; Younkin, Steven G; Katusic, Zvonimir S

2012-12-01

Existing evidence suggests that amyloid-β precursor protein (APP) causes endothelial dysfunction and contributes to pathogenesis of atherosclerosis. In the present study, experiments were designed to: (1) determine the mechanisms underlying endothelial dysfunction and (2) define the effects of peroxisome proliferator-activated receptor delta (PPARδ) ligand on endothelial function in transgenic Tg2576 mice overexpressing mutated human APP. Confocal microscopy and western blot analyses of wild-type mice aortas provided evidence that APP protein is mainly present in endothelial cells. Overexpression of APP significantly impaired endothelium-dependent relaxations to acetylcholine and phosphorylation of endothelial nitric oxide synthase at Ser(1177) in aortas. HPLC analysis revealed that tetrahydrobiopterin (BH(4)) levels were reduced in Tg2576 mice aortas. This was caused by increased oxidation of BH(4) and reduced expression and activity of GTP-cyclohydrolase I. Furthermore, gp91phox protein expression and superoxide anion production were increased in aortas of Tg2576 mice. This augmented superoxide formation was completely prevented by the NADPH oxidase inhibitor VAS2870. Expression of copper-/zinc-superoxide dismutase (Cu/ZnSOD) and extracellular SOD was downregulated. Treatment with PPARδ ligand GW501516 (2 mg/kg/day) for 14 days significantly increased BH(4) bioavailability and improved endothelium-dependent relaxations in Tg2576 mice aortas. GW501516 also normalized protein expression of gp91(phox) and SODs, thereby reducing production of superoxide anion in the aortas. Our results suggest that in APP transgenic mice loss of nitric oxide and increased oxidative stress are the major causes of endothelial dysfunction. The vascular protective effects of GW501516 in Tg2576 mice appear to be critically dependent on prevention of superoxide anion production.

Copper/zinc superoxide dismutase insufficiency impairs progesterone secretion and fertility in female mice.

PubMed

Noda, Yoshihiro; Ota, Kuniaki; Shirasawa, Takuji; Shimizu, Takahiko

2012-01-01

Copper/zinc superoxide dismutase (CuZn-SOD, SOD1) is one of the major antioxidant enzymes, and is localized in the cytoplasm to scavenge superoxide. To investigate the physiological role of SOD1 in the ovaries, we analyzed the fertility of Sod1-deficient female mice. To evaluate their hormonal metabolism, we measured pituitary and ovarian hormone levels in the plasma of the mutant mice. Plasma follicle-stimulating hormone, luteinizing hormone, and estradiol were not altered in the mutant compared to the wild-type females, while the plasma progesterone level was significantly reduced in the mutant females. Furthermore, the mutant mice showed decreased progesterone secretion under the condition of superovulation. In a histochemical analysis, we observed a remarkable reduction in the corpus luteum area in the mutant ovaries without atrophic changes. The mutant mice also displayed enhanced superoxide generation in the region surrounding the corpora lutea, which was associated with increased apoptotic cells and suppressed vasculature. These results suggested that SOD1 deficiency dysregulated luteal formation because of increased superoxide generation in the ovary. In vitro fertilization experiments showed no abnormal fertilization of Sod1-deficient oocytes. In addition, when Sod1-deficient embryos were transferred into the oviducts of wild-type females, mutant embryos developed at a normal rate, indicating that SOD1 deficiency in embryos did not cause miscarriage in the uterus of wild-type females. These results indicated that increased intracellular ROS impaired luteal formation and progesterone production in the mutant females, thus suggesting that SOD1 plays a crucial role in both the luteal function and the maintenance of fertility in female mice.

Effects of the peroxisome proliferator clofibric acid on superoxide dismutase expression in the human HepG2 hepatoma cell line.

PubMed

Bécuwe, P; Bianchi, A; Keller, J M; Dauça, M

1999-09-15

We examined the effects of clofibric acid, a peroxisome proliferator, on the production of superoxide radicals, on the levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE), and on the expression of superoxide dismutases (SODs) in the human HepG2 hepatoma cell line. To this end, HepG2 cells were treated for 1 or 5 days with 0.25, 0.50, or 0.75 mM clofibric acid. The production of superoxide radicals was only enhanced in HepG2 cells exposed for 5 days to the different clofibric acid concentrations. However, this overproduction of superoxide radicals was not accompanied by increased rates of lipid peroxidation, as the MDA and 4-HNE levels did not change significantly. Manganese (Mn) SOD activity was increased when HepG2 cells were treated for 1 day with 0.50 or 0.75 mM clofibric acid. For this duration of treatment, no change was observed in total SOD and copper/zinc (Cu/Zn) SOD activities. For a 5-day treatment, total SOD and MnSOD activities as well as the enzyme apoprotein and MnSOD mRNA levels increased whatever the clofibric acid concentration used. This transcriptional induction of the MnSOD gene was correlated with an activation of the activator protein-1 transcription factor for 1 and 5 days of treatment, but was independent of nuclear factor-kappa B and of peroxisome proliferator-activated receptor. On the other hand, the PP exerted very little effect if any on Cu,ZnSOD expression. In contrast to rodent data, PP treatment of human hepatoma cells induces MnSOD expression.

Martian Superoxide and Peroxide O2 Release (OR) Assay: A New Technology for Terrestrial and Planetary Applications

NASA Technical Reports Server (NTRS)

Georgiou, Christos D.; Zisimopoulos, Dimitrios; Panagiotidis, Konstantinos; Grintzalis, Kontantinos; Papapostolou, Ioannis; Quinn, Richard C.; McKay, Christopher P.; Sun, Henry J.

2015-01-01

This study presents an assay for the detection and quantification of soil metal superoxides and peroxides in regolith and soil. The O2 release (OR) assay is based on the enzymatic conversion of the hydrolysis products of metal oxides to O2, and their quantification by an O2 electrode based on the stoichiometry of the involved reactions: The intermediate product O2 from the hydrolysis of metal superoxides is converted by cytochrome c to O2, and also by superoxide dismutase (SOD) to 1/2 mol O2 and 1/2 mol H2O2, which is then converted by catalase (CAT) to 1/2 mol O2. The product H2O2 from the hydrolysis of metal peroxides and hydroperoxides is converted to 1/2 mol O2 by CAT. The assay-method was validated in a sealed sample chamber using a liquid-phase Clark-type O2 electrode with known concentrations of O2 and H2O2, and with commercial metal superoxide and peroxide mixed with Mars analogue Mojave and Atacama Desert soils. Carbonates and perchlorates, both present on Mars, do not interfere with the assay. The assay lower limit of detection, using luminescence quenching/optical sensing O2-electrodes, is 1 nmol O2 cm(exp. -3) or better. The activity of the assay enzymes SOD and cytochrome c was unaffected up to 6 Gy exposure by gamma-radiation, while CAT retained 100% and 40% of its activity at 3 and 6 Gy, respectively, demonstrating the suitability of these enzymes for planetary missions, e.g., in Mars or Europa.

Antibacterial Efficacy of Super-Oxidized Water on Enterococcus faecalis Biofilms in Root Canal

PubMed Central

Zan, Recai; Alacam, Tayfun; Hubbezoglu, Ihsan; Tunc, Tutku; Sumer, Zeynep; Alici, Oguzhan

2016-01-01

Background The success of endodontic treatment depends on a few crucial factors. One of these factors is the complete chemomechanic preparation of root canal against various bacteria. In particular, the effect of resistant bacteria may cause intense pain with flare-up and formation of periapical lesions. Therefore, the strong effect of irrigants plays an important role in terms of the complete elimination of these bacteria to achieve long-term successful treatment. Objectives The aim of this study was to investigate the antibacterial effects of super-oxidized water (SPO) in root canals infected with Enterococcus faecalis biofilms. Methods One hundred twenty single-root, premolar teeth were selected. Initially, the teeth were prepared and then disinfected. E. faecalis were inoculated and kept at 37°C for 24 hours in the root canals. The re-inoculation procedure was repeated on the first, fourth, seventh, and tenth days. The infected root canals were divided into one negative (saline) and one positive (sodium hypochlorite) control group and four experimental groups (super-oxidized water: 1, 2, 3, or 5 minutes) (n = 20). Paper points were placed in the root canals to control and evaluate the biofilm formation. Biofilms were counted on blood agar plates, and data was evaluated and statistically analyzed using one-way ANOVA and Tukey’s test. Results Although sodium hypochlorite (NaOCl) showed no statistically significant difference when compared with three and five minutes of SPO irrigation (P > 0.05), NaOCl showed statistically significant differences among all other groups (P < 0.05). Conclusions Super-oxidized water indicated a remarkable and similar bactericidal effect to that of traditional NaOCl against E. faecalis biofilms. In terms of successful endodontic treatment approaches, super-oxidized water may be used as an effective irrigation solution in clinics. PMID:27800142

Insights on germinability and desiccation tolerance in developing neem seeds (Azadirachta indica): Role of AOS, antioxidative enzymes and dehydrin-like protein.

PubMed

Sahu, Balram; Sahu, Alok Kumar; Chennareddy, Srinivasa Rao; Soni, Avinash; Naithani, Subhash Chandra

2017-03-01

The germinability and desiccation tolerance (DT) in developing seed are regulated by cellular metabolism involving active oxygen species (AOS) and protective proteins during maturation drying. The aim of the present investigation was to unravel the functions of AOS (superoxide, H 2 O 2 and OH-radical), antioxidative enzymes (SOD, CAT and APX) and dehydrin-like proteins in regulating the germinability and DT in undried and artificially desiccated developing neem seeds. Germination was first observed in seeds of 8 weeks after anthesis (waa) whereas DT was noticed from 9 waa. High levels of superoxide in undried and artificially desiccated seeds of 9 waa were rapidly declined up to 15 waa with simultaneous increase in levels of SOD (quantitative and isoenzymes) that dismutates superoxide with corresponding formation and accumulation of H 2 O 2 . Activities and isoenzymes of APX and CAT were promoted in seeds from 9 to 12 waa. Intensity of dehydrin-like proteins increased as development progressed in seeds with higher intensities in slow dried (SD) seeds. Desiccation modulated the metabolism for the acquisition of germinability and DT in the developing neem seeds from 8 to 15 waa by altering the levels of superoxide, H 2 O 2 and OH-radical those possibly act as signalling molecules for reprogramming protective proteins. Desiccation mediated the expression of new bands of SOD and APX in undried as well as SD seeds during 9-12 waa but the bands were more intense in SD seeds. The superoxide and H 2 O 2 -regulated intensity of dehydrin-like protein in SD seeds further validated our conclusion. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Green tea extract (epigallocatechin-3-gallate) reduces efficacy of radiotherapy on prostate cancer cells.

PubMed

Thomas, Francis; Holly, Jeff M P; Persad, Rajendra; Bahl, Amit; Perks, Claire M

2011-08-01

To assess the influence of epigallocatechin-3-gallate (EGCG) on the efficacy of ionizing radiation on prostate cancer cells because of the increased use of dietary interventions, especially by patients with prostate cancer. Radiotherapy is used to treat localized prostate cancer. Some people consume green tea (EGCG) as a chemopreventive agent against prostate cancer. Green tea can act as an antioxidant and induce superoxide dismutase enzymes, which could scavenge the free oxygen radicals generated by radiotherapy. Prostate cancer cell line DU145 cells were treated with EGCG or radiotherapy, or both. Cell death was assessed using trypan blue cell counting, and apoptosis was confirmed by assessing poly (adenosine phosphate ribose) polymerase cleavage. The antioxidant potential was assessed using Western immunoblotting for manganese superoxide dismutase and copper zinc superoxide dismutase enzymes. Radiotherapy was delivered using a linear accelerator. Cell cycle analysis was performed using flow cytometry. Radiotherapy at 3.5 Gy induced a 5.9-fold increase in apoptosis of DU145 cells. Subapoptotic doses of EGCG (1.5-7.5 μM) significantly reduced ionizing radiation-induced apoptosis (P < .001), with the inhibitory effect of EGCG on ionizing radiation being most effective when added 30 minutes before radiotherapy (P < .001). In addition, when radiotherapy and EGCG were used together, an approximate 1.5-fold increase in manganese superoxide dismutase levels was seen compared with the control and a 2-fold increase compared with radiotherapy alone. Radiotherapy is effective in inducing apoptosis in DU145 cells, but its effect was significantly reduced in the presence of EGCG, and this was associated with an increase in the induction of manganese superoxide dismutase. Copyright © 2011 Elsevier Inc. All rights reserved.

Deletion of angiotensin II type 1 receptor gene or scavenge of superoxide prevents chronic alcohol-induced aortic damage and remodelling.

PubMed

Bai, Yang; Tan, Yi; Wang, Bo; Miao, Xiao; Chen, Qiang; Zheng, Yang; Cai, Lu

2012-10-01

To investigate whether chronic alcohol consumption induces vascular injury via angiotensin II (Ang II) type 1 (AT1) receptor-dependent superoxide generation, male transgenic mice with knockout of AT1 gene (AT1-KO) and age-matched wild-type (WT) C57BL/6 mice were pair-fed a modified Lieber-DeCarli alcohol or isocaloric maltose dextrin control liquid diet for 2 months. Ethanol content (%, W/V) in the diet was 4.8 (34% of total calories) at initiation, and gradually increased up to 5.4 (38% of total calories). For some WT mice with and without alcohol treatment, superoxide dismutase mimetic (MnTMPyP) was given simultaneously by intraperitoneal injection at 5 mg/kg body weight daily for 2 months. At the end of studies, aortas were harvested for histopathological and immunohistochemical examination. Significant increases in the wall thickness and structural disarrangement of aorta were found in alcohol group, along with significant increases in aortic oxidative and/or nitrosative damage, expressions of NADPH oxidases (NOXs), inflammatory response, cell death and proliferation, and remodelling (fibrosis). However, these pathological changes were completely attenuated in alcohol-treated AT1-KO mice or in alcohol-treated WT mice that were also simultaneously treated with MnTMPyP for 2 months. These results suggest that chronic alcohol consumption may activate NOX via Ang II/AT1 receptor, to generate superoxide and associated peroxynitrite that in turn causes aortic nitrosative damage, inflammation, cell death and proliferation, and remodelling. Therefore, blocking Ang II/AT1 system or scavenging superoxide may become a potential preventive and/therapeutic approach to alcoholic vascular damage. © 2012 The Authors Journal of Cellular and Molecular Medicine © 2012 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Embedding the Ni-SOD mimetic Ni-NCC within a polypeptide sequence alters the specificity of the reaction pathway.

PubMed

Krause, Mary E; Glass, Amanda M; Jackson, Timothy A; Laurence, Jennifer S

2013-01-07

The unique metal abstracting peptide asparagine-cysteine-cysteine (NCC) binds nickel in a square planar 2N:2S geometry and acts as a mimic of the enzyme nickel superoxide dismutase (Ni-SOD). The Ni-NCC tripeptide complex undergoes rapid, site-specific chiral inversion to dld-NCC in the presence of oxygen. Superoxide scavenging activity increases proportionally with the degree of chiral inversion. Characterization of the NCC sequence within longer peptides with absorption, circular dichroism (CD), and magnetic CD (MCD) spectroscopies and mass spectrometry (MS) shows that the geometry of metal coordination is maintained, though the electronic properties of the complex are varied to a small extent because of bis-amide, rather than amine/amide, coordination. In addition, both Ni-tripeptide and Ni-pentapeptide complexes have charges of -2. This study demonstrates that the chiral inversion chemistry does not occur when NCC is embedded in a longer polypeptide sequence. Nonetheless, the superoxide scavenging reactivity of the embedded Ni-NCC module is similar to that of the chirally inverted tripeptide complex, which is consistent with a minor change in the reduction potential for the Ni-pentapeptide complex. Together, this suggests that the charge of the complex could affect the SOD activity as much as a change in the primary coordination sphere. In Ni-NCC and other Ni-SOD mimics, changes in chirality, superoxide scavenging activity, and oxidation of the peptide itself all depend on the presence of dioxygen or its reduced derivatives (e.g., superoxide), and the extent to which each of these distinct reactions occurs is ruled by electronic and steric effects that emenate from the organization of ligands around the metal center.

Superoxide differentially controls pulmonary and systemic vascular tone through multiple signalling pathways

PubMed Central

Snetkov, Vladimir A.; Smirnov, Sergey V.; Kua, Justin; Aaronson, Philip I.; Ward, Jeremy P.T.; Knock, Greg A.

2011-01-01

Aims The aim of this study was to determine the relative importance of Ca2+ sensitization, ion channels, and intracellular Ca2+ ([Ca2+]i) in the mixed constrictor/relaxation actions of superoxide anion on systemic and pulmonary arteries. Methods and results Pulmonary and mesenteric arteries were obtained from rat. Superoxide was generated in arteries and cells with 6-anilino-5,8-quinolinequinone (LY83583). Following pre-constriction with U46619, 10 μmol/L LY83583 caused constriction in pulmonary and relaxation in mesenteric arteries. Both constrictor and relaxant actions of LY83583 were inhibited by superoxide dismutase and catalase. LY83583 caused Rho-kinase-dependent constriction in α-toxin-permeabilized pulmonary but not mesenteric arteries. Phosphorylation of myosin phosphatase-targeting subunit-1 (MYPT-1; as determined by western blot), was enhanced by LY83583 in pulmonary artery only. However, in both artery types, changes in tension were closely correlated with changes in phosphorylation of the 20 kDa myosin light chain as well as changes in [Ca2+]i (as measured with Fura PE-3), with LY83583 causing increases in pulmonary and decreases in mesenteric arteries. When U46619 was replaced by 30 mmol/L K+, all changes in [Ca2+]i were abolished and LY83583 constricted both artery types. The KV channel inhibitor 4-aminopyridine abolished the LY83583-induced relaxation in mesenteric artery without affecting constriction in pulmonary artery. However, LY83583 caused a similar hyperpolarizing shift in the steady-state activation of KV current in isolated smooth muscle cells of both artery types. Conclusions Superoxide only causes Rho-kinase-dependent Ca2+ sensitization in pulmonary artery, resulting in constriction, and whilst it opens KV channels in both artery types, this only results in relaxation in mesenteric. PMID:20805095

The In Vitro Influence of a Genetic Superoxide-Hydrogen Peroxide Imbalance on Immunosenescence.

PubMed

Barbisan, Fernanda; Azzolin, Verônica Farina; Ribeiro, Euler Esteves; Duarte, Marta Maria Medeiros Frescura; da Cruz, Ivana Beatrice Mânica

2017-08-01

As superoxide is a key molecule of inflammatory activation, superoxide-hydrogen peroxide (S-HP) imbalance genetically caused could alter immunosenescence patterns. To test this hypothesis, we collected and cultured peripheral blood mononuclear cells (PBMCs) carrier's different genotypes of a genetic polymorphism located in the superoxide dismutase manganese-dependent gene (Val16Ala-SOD2). We used an in vitro genetic model based on previous studies, which suggested an association between homozygous genotypes (AA and VV) and alterations in oxidative-inflammatory mediators. PBMCs collected from young healthy volunteers were cultured in the presence of phytohemagglutinin, as well as the following cell culture passages obtained from the 72-hour initial culture. Each follow passage started with the same cell concentration (1 × 10 5 cells). The general immunosenescence pattern was observed independent of SOD2 genotypes: cellular proliferation until the 15th passage, when cellular arrestment occurred in the G0/G1 phase. From the 10th passage, a higher proliferative state was observed, indicating inflammatory hyperactivation, with an increase in the levels of inflammatory cytokines (IL-1, IL-6, and TNFα), nitric oxide, superoxide, lipoperoxidation, protein carbonylation, reactive oxygen species, and DNA damage. The S-HP imbalance affected the intensity of some immunosenescence parameters. AA cells, which present basal high HP levels, were associated with higher DNA damage and lipoperoxidation levels, whereas VV, which present basal high S levels, was associated with higher proinflammatory cytokine levels. In summary, the results suggested that a basal S-HP imbalance could affect the intensity of some immunosenescence markers, and this influence could explain the potential association between an imbalance of genotypes (AA and VV) and the risk of developing some chronic diseases.

Superoxide and its metabolism during germination and axis growth of Vigna radiata (L.) Wilczek seeds

PubMed Central

Singh, Khangembam Lenin; Chaudhuri, Abira; Kar, Rup Kumar

2014-01-01

Involvement of reactive oxygen species in regulation of plant growth and development is recently being demonstrated with various results depending on the experimental system and plant species. Role of superoxide and its metabolism in germination and axis growth was investigated in case of Vigna radiata seeds, a non-endospermous leguminous species having epigeal germination, by studying the effect of different reactive oxygen species (ROS) inhibitors, distribution of O2•ˉ and H2O2 and ROS enzyme profile in axes. Germination percentage and axis growth were determined under treatment with ROS inhibitors and scavengers. Localization of O2•ˉ and H2O2 was done using nitroblue tetrazolium (NBT) and 3,3′,5,5′-tetramethyl benzidine dihydrochloride hydrate (TMB), respectively. Apoplastic level of O2•ˉ was monitored by spectrophotometric analysis of bathing medium of axes. Profiles of NADPH oxidase and superoxide dismutase (SOD) were studied by in-gel assay. Germination was retarded by treatments affecting ROS level except H2O2 scavengers, while axis growth was retarded by all. Superoxide synthesis inhibitor and scavenger prevented H2O2 accumulation in axes in later phase as revealed from TMB staining. Activity of Cu/Zn SOD1 was initially high and declined thereafter. Superoxide being produced in apoplast possibly by NADPH oxidase activity is further metabolized to •OH via H2O2. Germination process depends possibly on •OH production in the axes. Post-germinative axis growth requires O2•ˉ while the differentiating zone of axis (radicle) requires H2O2 for cell wall stiffening. PMID:25763616

Peroxide generation by p47phox-Src activation of Nox2 has a key role in protein kinase C-induced arterial smooth muscle contraction.

PubMed

Gupte, Sachin A; Kaminski, Pawel M; George, Shimran; Kouznestova, Lioubov; Olson, Susan C; Mathew, Rajamma; Hintze, Thomas H; Wolin, Michael S

2009-04-01

Protein kinase C (PKC) stimulation of NAD(P)H oxidases (Nox) is an important component of multiple vascular disease processes; however, the relationship between oxidase activation and the regulation of vascular smooth muscle contraction by PKC remains poorly understood. Therefore, we examined the signaling cascade of PKC-elicited Nox activation and the role of superoxide and hydrogen peroxide in mediating PKC-induced vascular contraction. Endothelium-denuded bovine coronary arteries showed a PKC-dependent basal production of lucigenin (5 muM)-detected Nox oxidase-derived superoxide, which was stimulated fourfold by PKC activation with 10 muM phorbol 12,13-dibutyrate (PDBu). PDBu appeared to increase superoxide generation by Nox2 through both p47(phox) and peroxide-dependent Src activation mechanisms based on the actions of inhibitors, properties of Src phosphorylation, and the loss of responses in aorta from mice deficient in Nox2 and p47(phox). The actions of inhibitors of contractile regulating mechanisms, scavengers of superoxide and peroxide, and responses in knockout mouse aortas suggest that a major component of the contraction elicited by PDBu appeared to be mediated through peroxide derived from Nox2 activation stimulating force generation through Rho kinase and calmodulin kinase-II mechanisms. Superoxide generated by PDBu also attenuated relaxation to nitroglycerin. Peroxide-derived from Nox2 activation by PKC appeared to be a major contributor to the thromboxane A(2) receptor agonist U46619 (100 nM)-elicited contraction of coronary arteries. Thus a p47(phox) and Src kinase activation of peroxide production by Nox2 appears to be an important contributor to vascular contractile mechanisms mediated through activation of PKC.

Martian Superoxide and Peroxide O2 Release (OR) Assay: A New Technology for Terrestrial and Planetary Applications.

PubMed

Georgiou, Christos D; Zisimopoulos, Dimitrios; Panagiotidis, Konstantinos; Grintzalis, Konstantinos; Papapostolou, Ioannis; Quinn, Richard C; McKay, Christopher P; Sun, Henry J

2016-02-01

This study presents an assay for the detection and quantification of soil metal superoxides and peroxides in regolith and soil. The O2 release (OR) assay is based on the enzymatic conversion of the hydrolysis products of metal oxides to O2 and their quantification by an O2 electrode based on the stoichiometry of the involved reactions. The intermediate product O₂˙⁻ from the hydrolysis of metal superoxides is converted by cytochrome c to O2 and by superoxide dismutase (SOD) to ½ mol O2 and ½ mol H2O2, which is then converted by catalase (CAT) to ½ mol O2. The product H2O2 from the hydrolysis of metal peroxides and hydroperoxides is converted to ½ mol O2 by CAT. The assay method was validated in a sealed sample chamber by using a liquid-phase Clark-type O2 electrode with known concentrations of O₂˙⁻ and H2O2, and commercial metal superoxide and peroxide mixed with Mars analog Mojave and Atacama Desert soils. Carbonates and perchlorates, both present on Mars, do not interfere with the assay. The assay lower limit of detection, when using luminescence quenching/optical sensing O2-electrodes, is 1 nmol O2 cm(-3) or better. The activity of the assay enzymes SOD and cytochrome c was unaffected up to 6 Gy exposure by γ radiation, while CAT retained 100% and 40% of its activity at 3 and 6 Gy, respectively, which demonstrates the suitability of these enzymes for planetary missions, for example, on Mars or Europa.

Can ferric-superoxide act as a potential oxidant in P450(cam)? QM/MM investigation of hydroxylation, epoxidation, and sulfoxidation.

PubMed

Lai, Wenzhen; Shaik, Sason

2011-04-13

In view of recent reports of high reactivity of ferric-superoxide species in heme and nonheme systems (Morokuma et al. J. Am. Chem. Soc. 2010, 132, 11993-12005; Que et al. Inorg. Chem. 2010, 49, 3618-3628; Nam et al. J. Am. Chem. Soc. 2010, 132, 5958-5959; J. Am. Chem. Soc. 2010, 132, 10668-10670), we use herein combined quantum mechanics/molecular mechanics (QM/MM) methods to explore the potential reactivity of P450(cam) ferric-superoxide toward hydroxylation, epoxidation, and sulfoxidation. The calculations demonstrate that P450 ferric-superoxide is a sluggish oxidant compared with the high-valent oxoiron porphyrin cation-radical species. As such, unlike heme enzymes with a histidine axial ligand, the P450 superoxo species does not function as an oxidant in P450(cam). The origin of this different behavior of the superoxo species of P450 vis-à-vis other heme enzymes like tryptophan 2, 3-dioxygenase (TDO) is traced to the ability of the latter superoxo species to make a stronger FeOO-X (X = H,C) bond and to stabilize the corresponding bond-activation transition states by resonance with charge-transfer configurations. By contrast, the negatively charged thiolate ligand in the P450 superoxo species minimizes the mixing of charge transfer configurations in the transition state and raises the reaction barrier. However, as we demonstrate, an external electric field oriented along the Fe-O axis with a direction pointing from Fe toward O will quench Cpd I formation by slowing the reduction of ferric-superoxide and will simultaneously lower the barriers for oxidation by the latter species, thereby enabling observation of superoxo chemistry in P450. Other options for nascent superoxo reactivity in P450 are discussed. © 2011 American Chemical Society

Immobilization of Superoxide Dismutase on Polyelectrolyte-Functionalized Titania Nanosheets.

PubMed

Rouster, Paul; Pavlovic, Marko; Szilagyi, Istvan

2018-02-16

The superoxide dismutase (SOD) enzyme was successfully immobilized on titania nanosheets (TNS) functionalized with the poly(diallyldimethylammonium chloride) (PDADMAC) polyelectrolyte. The TNS-PDADMAC solid support was prepared by hydrothermal synthesis followed by self-assembled polyelectrolyte layer formation. It was found that SOD strongly adsorbed onto oppositely charged TNS-PDADMAC through electrostatic and hydrophobic interactions. The TNS-PDADMAC-SOD material was characterized by light scattering and microscopy techniques. Colloidal stability studies revealed that the obtained nanocomposites possessed good resistance against salt-induced aggregation in aqueous suspensions. The enzyme kept its functional integrity upon immobilization; therefore, TNS-PDADMAC-SOD showed excellent superoxide radical anion scavenging activity. The developed system is a promising candidate for applications in which suspensions of antioxidant activity are required in the manufacturing processes. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the use of L-012, a luminol-based chemiluminescent probe, for detecting superoxide and identifying inhibitors of NADPH oxidase: A re-evaluation

PubMed Central

Zielonka, Jacek; Lambeth, J. David; Kalyanaraman, Balaraman

2014-01-01

L-012, a luminol-based chemiluminescent (CL) probe, is widely used in vitro and in vivo to detect NADPH oxidase (Nox)-derived superoxide (O2·−) and identify Nox inhibitors. Yet understanding of the free radical chemistry of L-012 probe is still lacking. We report that peroxidase and H2O2 induce superoxide dismutase (SOD)-sensitive, L-012-derived CL in the presence of oxygen. O2·− alone does not react with L-012 to emit luminescence. Self-generated O2·− during oxidation of L-012 and luminol-analogs artifactually induce CL inhibitable by SOD. These aspects make assays based on luminol analogs less than ideal for specific detection and identification of O2·− and NOX inhibitors. PMID:24080119

Shedding Light on the Oxygen Reduction Reaction Mechanism in Ether-Based Electrolyte Solutions: A Study Using Operando UV-Vis Spectroscopy.

PubMed

Hirshberg, Daniel; Sharon, Daniel; Afri, Michal; Lavi, Ronit; Frimer, Aryeh A; Metoki, Noa; Eliaz, Noam; Kwak, Won-Jin; Sun, Yang-Kook; Aurbach, Doron

2018-04-04

Using UV-vis spectroscopy in conjunction with various electrochemical techniques, we have developed a new effective operando methodology for investigating the oxygen reduction reactions (ORRs) and their mechanisms in nonaqueous solutions. We can follow the in situ formation and presence of superoxide moieties during ORR as a function of solvent, cations, anions, and additives in the solution. Thus, using operando UV-vis spectroscopy, we found evidence for the formation of superoxide radical anions during oxygen reduction in LiTFSI/diglyme electrolyte solutions. Nitro blue tetrazolium (NBT) was used to indicate the presence of superoxide moieties based on its unique spectral response. Indeed, the spectral response of NBT containing solutions undergoing ORR could provide a direct indication for the level of association of the Li cations with the electrolyte anions.

Antiferromagnetic S=1/2 spin chain driven by p-orbital ordering in CsO2.

PubMed

Riyadi, Syarif; Zhang, Baomin; de Groot, Robert A; Caretta, Antonio; van Loosdrecht, Paul H M; Palstra, Thomas T M; Blake, Graeme R

2012-05-25

We demonstrate, using a combination of experiment and density functional theory, that orbital ordering drives the formation of a one-dimensional (1D) S=1/2 antiferromagnetic spin chain in the 3D rocksalt structure of cesium superoxide (CsO2). The magnetic superoxide anion (O2(-)) exhibits degeneracy of its 2p-derived molecular orbitals, which is lifted by a structural distortion on cooling. A spin chain is then formed by zigzag ordering of the half-filled superoxide orbitals, promoting a superexchange pathway mediated by the p(z) orbitals of Cs(+) along only one crystal direction. This scenario is analogous to the 3d-orbital-driven spin chain found in the perovskite KCuF3 and is the first example of an inorganic quantum spin system with unpaired p electrons.

Superoxide radical anion scavenging and dismutation by some Cu2+ and Mn2+ complexes: A pulse radiolysis study

NASA Astrophysics Data System (ADS)

Joshi, Ravi

2017-10-01

Copper (Cu) and manganese (Mn) ions are catalytic centers, in complexed form, in scavenging and dismutation process of superoxide radicals anion (O2.-) by superoxide dismutase enzyme. In the present work, fast reaction kinetics and mechanism of scavenging and dismutation of O2.- by Cu2+, Mn2+ and their complexes formed with some natural ligands have been studied using pulse radiolysis technique. Catechol, gentisic acid, tetrahydroxyquinone, tyrosine, tryptophan, embelin and bilirubin have been used as low molecular weight natural ligands for Cu2+ and Mn2+ to understand superoxide radical scavenging and dismutation reactions. These complexes have been found to be efficient scavengers of O2.- (k 107-109 M-1 s-1). The effects of nature of metal ion and ligand, and stoichiometry of complex on scavenging reaction rate constants are reported. Higher scavenging rate constants have been observed with complexes of: (1) Cu2+ as compared to Mn2+, and (2) at [ligand]/[metal] ratio of one as compared to two. A clear evidence of O2.- dismutation by free metal ions and some of the complexes has been observed. The study suggests that complexes of Cu2+ and Mn2+ with small natural ligands can also act as SOD mimics.

Use of rapid-scan EPR to improve detection sensitivity for spin-trapped radicals.

PubMed

Mitchell, Deborah G; Rosen, Gerald M; Tseitlin, Mark; Symmes, Breanna; Eaton, Sandra S; Eaton, Gareth R

2013-07-16

The short lifetime of superoxide and the low rates of formation expected in vivo make detection by standard continuous wave (CW) electron paramagnetic resonance (EPR) challenging. The new rapid-scan EPR method offers improved sensitivity for these types of samples. In rapid-scan EPR, the magnetic field is scanned through resonance in a time that is short relative to electron spin relaxation times, and data are processed to obtain the absorption spectrum. To validate the application of rapid-scan EPR to spin trapping, superoxide was generated by the reaction of xanthine oxidase and hypoxanthine with rates of 0.1-6.0 μM/min and trapped with 5-tert-butoxycarbonyl-5-methyl-1-pyrroline-N-oxide (BMPO). Spin trapping with BMPO to form the BMPO-OOH adduct converts the very short-lived superoxide radical into a more stable spin adduct. There is good agreement between the hyperfine splitting parameters obtained for BMPO-OOH by CW and rapid-scan EPR. For the same signal acquisition time, the signal/noise ratio is >40 times higher for rapid-scan than for CW EPR. Rapid-scan EPR can detect superoxide produced by Enterococcus faecalis at rates that are too low for detection by CW EPR. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Effects of season on boar semen parameters and antioxidant enzymes in the south subtropical region in Brazil.

PubMed

Argenti, L E; Parmeggiani, B S; Leipnitz, G; Weber, A; Pereira, G R; Bustamante-Filho, I C

2018-02-01

Although boar semen productivity is affected by seasonality, its effects are not equal among different regions which raise concerns regarding the profitability of boar stud farms. Therefore, the goals of this study were (i) to evaluate the seasonal effect on semen production in a commercial boar stud farm located in a subtropical climate region and (ii) to verify whether the activities of superoxide dismutase and glutathione peroxidase in spermatozoa and seminal plasma were associated with seminal traits of fresh and cooled semen. Nine boars were collected twice per season, and routine seminal parameter analyses were performed together with superoxide dismutase and glutathione peroxidase activities in seminal plasma and spermatozoa. Despite a reduction in sperm concentration in spring and summer, most seminal parameters were constant year-round. Temperature-humidity index was higher in the summer compared to spring, autumn and winter (p < .05). Superoxide dismutase activity in spermatozoa was increased in summer compared to autumn and winter (p < .05). The activities of both enzymes in seminal plasma and spermatozoa glutathione peroxidase remained unaltered throughout the seasons. In conclusion, seasonality showed little influence in overall boar seminal parameters despite microclimatic differences among seasons, and spermatozoa collected during summer increased superoxide dismutase activity. © 2018 Blackwell Verlag GmbH.

A novel multi-hyphenated analytical method to simultaneously determine xanthine oxidase inhibitors and superoxide anion scavengers in natural products.

PubMed

Qi, Jin; Sun, Li-Qiong; Qian, Steven Y; Yu, Bo-Yang

2017-09-01

Natural products, such as rosmarinic acid and apigenin, can act as xanthine oxidase inhibitors (XOIs) as well as superoxide anion scavengers, and have potential for treatment of diseases associated with high uric acid levels and oxidative stress. However, efficient simultaneous screening of these two bioactivities in natural products has been challenging. We have developed a novel method by assembling a multi-hyphenated high performance liquid chromatography (HPLC) system that combines a photo-diode array, chemiluminescence detector and a HPLC system with a variable wavelength detector, to simultaneously detect components that act as both XOIs and superoxide anion scavengers in natural products. Superoxide anion scavenging activity in the analyte was measured by on-line chemiluminescence chromatography based on pyrogallol-luminol oxidation, while xanthine oxidase inhibitory activity was determined by semi-on-line HPLC analysis. After optimizing multiple elements, including chromatographic conditions (e.g., organic solvent concentration and mobile phase pH), concentrations of xanthine/xanthine oxidase and reaction temperature, our validated analytical method was capable of mixed sample analysis. The final results from our method are presented in an easily understood visual format including comprehensive bioactivity data of natural products. Copyright © 2017. Published by Elsevier B.V.

CTT1 overexpression increases life span of calorie-restricted Saccharomyces cerevisiae deficient in Sod1.

PubMed

Rona, Germana; Herdeiro, Ricardo; Mathias, Cristiane Juliano; Torres, Fernando Araripe; Pereira, Marcos Dias; Eleutherio, Elis

2015-06-01

Studies using different organisms revealed that reducing calorie intake, without malnutrition, known as calorie restriction (CR), increases life span, but its mechanism is still unkown. Using the yeast Saccharomyces cerevisiae as eukaryotic model, we observed that Cu, Zn-superoxide dismutase (Sod1p) is required to increase longevity, as well as to confer protection against lipid and protein oxidation under CR. Old cells of sod1 strain also presented a premature induction of apoptosis. However, when CTT1 (which codes for cytosolic catalase) was overexpressed, sod1 and WT strains showed similar survival rates. Furthermore, CTT1 overexpression decreased lipid peroxidation and delayed the induction of apoptotic process. Superoxide is rapidly converted to hydrogen peroxide by superoxide dismutase, but it also undergoes spontaneous dismutation albeit at a slower rate. However, the quantity of peroxide produced from superoxide in this way is two-fold higher. Peroxide degradation, catalyzed by catalase, is of vital importance, because in the presence of a reducer transition metal peroxide is reduced to the highly reactive hydroxyl radical, which reacts indiscriminately with most cellular constituents. These findings might explain why overexpression of catalase was able to overcome the deficiency of Sod1p, increasing life span in response to CR.

Nitroxidative chemistry interferes with fluorescent probe chemistry: implications for nitric oxide detection using 2,3-diaminonaphthalene.

PubMed

Hu, Teh-Min; Chiu, Shih-Jiuan; Hsu, Yu-Ming

2014-08-22

Simultaneous production of nitric oxide (NO) and superoxide generates peroxynitrite and causes nitroxidative stress. The fluorometric method for NO detection is based on the formation of a fluorescent product from the reaction of a nonfluorescent probe molecule with NO-derived nitrosating species. Here, we present an example of how nitroxidative chemistry could interact with fluorescent probe chemistry. 2,3-Naphthotriazole (NAT) is the NO-derived fluorescent product of 2,3-diaminonaphthalene (DAN), a commonly used NO-detecting molecule. We show that NO/superoxide cogeneration, and particularly peroxynitrite, mediates the chemical decomposition of NAT. Moreover, the extent of NAT decomposition depends on the relative fluxes of NO and superoxide; the maximum effect being reached at almost equivalent generation rates for both radicals. The rate constant for the reaction of NAT with peroxynitrite was determined to be 2.2×10(3)M(-1)s(-1). Further, various peroxynitrite scavengers were shown to effectively inhibit NO/superoxide- and peroxynitrite-mediated decomposition of NAT. Taken together, the present study suggests that the interference of a fluorometric NO assay can be originated from the interaction between the final fluorescent product and the formed reactive nitrogen and oxygen species. Copyright © 2014 Elsevier Inc. All rights reserved.

Reaction of ferrate (VI)/ferrate (V) with hydrogen peroxide and superoxide anion--a stopped-flow and premix pulse radiolysis study.

PubMed

Rush, J D; Zhao, Z; Bielski, B H

1996-03-01

The reduction of ferrate(VI) to ferrate(V) by superoxide ions was studied over the pH range 2.6-13.0 using the premix pulse radiolysis technique. The pH dependence indicates that only the unstable protonated forms of ferrate, H2FeO4 (pKa3.5) and HFeO4- (pKa7.3) are reactive, k(HFeO4(-) + O2) = (1.7 +/- 0.2) x 10(7) M-1 s-1. The stable ferrate ion, FeO4(2-), showed no significant reactivity towards either hydrogen peroxide or superoxide anion. The rate constants for the spontaneous dimerization and decomposition of the protonated ferrates, e.g. k(HFeO4(-) + HFe04) approximately 250 M-1s-1, are orders of magnitude slower than their corresponding reduction reduction by superoxide indicating an outer-sphere mode of electron transfer for the latter process. In contrast the ferrate(VI) species H3FeO4+ (pKa = 1.6 +/- 0.2), H2FeO4, and HFeO4- oxidize hydrogen peroxide, e.g. k(HFeO4(-) + H2O2) = 170 M-1 s-1), at rates which correspond closely to their dimerization rates suggesting an inner-sphere controlled mechanism.

[Antimutagenic action of superoxide dismutase on sodium azide- and nitrosoguanidine-induced mutagenesis in Salmonella typhimurium TA 1535].

PubMed

Vorob'eva, L I; Cherdyntseva, T A; Aver'ianov, A A; Abilev, S K

1993-05-01

It was shown that superoxide dismutase (SOD) decreased the mutagenic action of sodium azide (NaN3) and N-methyl-N'-nitro-N-nitrosoguanidine in Salmonella typhimurium TA1535. Catalase and quenchers of hydroxyl radicals showed, unlike SOD no effect on the mutagenicity of NaN3. Cell extract from propionic acid bacteria also possessed the antimutagenic activity, only partially depending on the SOD activity.

Glutathione protects Candida albicans against horseradish volatile oil.

PubMed

Bertóti, Regina; Vasas, Gábor; Gonda, Sándor; Nguyen, Nhat Minh; Szőke, Éva; Jakab, Ágnes; Pócsi, István; Emri, Tamás

2016-10-01

Horseradish essential oil (HREO; a natural mixture of different isothiocyanates) had strong fungicide effect against Candida albicans both in volatile and liquid phase. In liquid phase this antifungal effect was more significant than those of its main components allyl, and 2-phenylethyl isothiocyanate. HREO, at sublethal concentration, induced oxidative stress which was characterized with elevated superoxide content and up-regulated specific glutathione reductase, glutathione peroxidase, catalase and superoxide dismutase activities. Induction of specific glutathione S-transferase activities as marker of glutathione (GSH) dependent detoxification was also observed. At higher concentration, HREO depleted the GSH pool, increased heavily the superoxide production and killed the cells rapidly. HREO and the GSH pool depleting agent, 1-chlore-2,4-dinitrobenzene showed strong synergism when they were applied together to kill C. albicans cells. Based on all these, we assume that GSH metabolism protects fungi against isothiocyanates. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ultrasound promoted N-alkylation of pyrrole using potassium superoxide as base in crown ether.

PubMed

Yim, E S; Park, M K; Han, B H

1997-04-01

Ultrasound accelerates the N-alkylation of pyrrole by alkylating reagents using potassium superoxide as base in the presence of 18-crown-6. A much lower yield of N-alkylated pyrrole was realized in the absence of ultrasound. N-alkylating reagents employed for pyrrole are methyl iodide, ethyl bromide, benzyl bromide, as well as acrylonitrile allyl cyanide and methyl acrylate. In an extension of this work, we have found that ultrasound was not necessary for the N-alkylation of indole and alkyl amine, such as diphenyl amine and piperidine with alkyl halides using our reagents. In all cases we observed that the 18-crown-6 catalyzed N-alkylation reaction gives higher yields of N-alkylated products than that without crown ether, when potassium superoxide was used as base. These observations are probably due to the potassium-crown complex which can be released when the reaction goes to completion.

Superoxide dismutase from Trichuris ovis--inhibition by benzimidazoles and pyrimidine derivatives.

PubMed

Sanchez-Moreno, M; Garcia-Rejon, L; Salas, I; Osuna, A; Monteoliva, M

1992-01-01

Three superoxide dismutase isoenzymes of different cellular location were detected in an homogenate of Trichuris ovis. Each of these molecular forms was purified by differential centrifugation and precipitation with ammonium sulphate, followed by chromatography on DEAE-cellulose and Sephadex G-75 columns. The activity levels of the two molecular forms detected in the mitochondrial (one cyanide sensitive Cu-Zn-SOD and the other cyanide insensitive Mn-SOD) were higher than that of the superoxide dismutase detected in the cytoplasmic fraction (cyanide sensitive Cu-Zn-SOD). All molecular forms present evident differences to the SODs contained in the host liver. Molecular mass and some of the physical and chemical properties of the enzyme was determined for all three molecular forms. An inhibitory effect on the SOD of the parasite an the host was detected with a series of compounds, some of which markedly inhibited parasite enzyme but not host enzyme.

Hepatoprotective effects of Poly-[hemoglobin-superoxide dismutase-catalase-carbonic anhydrase] on alcohol-damaged primary rat hepatocyte culture in vitro.

PubMed

Jiang, Wenhua; Bian, Yuzhu; Wang, Zhenghui; Chang, Thomas Ming Swi

2017-02-01

We have prepared a novel nanobiotherapeutic, Poly-[hemoglobin-superoxide dismutase-catalase-carbonic anhydrase], which not only transports both oxygen and carbon dioxide but also a therapeutic antioxidant. Our previous study in a severe sustained 90 min hemorrhagic shock rat model shows that it has a hepatoprotective effect. We investigate its hepatoprotective effect further in this present report using an alcohol-damaged primary hepatocyte culture model. Results show that it significantly reduced ethanol-induced AST release, lipid peroxidation, and ROS production in rat primary hepatocytes culture. It also significantly enhanced the viability of ethanol-treated hepatocytes. Thus, the result shows that Poly-[hemoglobin-superoxide dismutase-catalase-carbonic anhydrase] also has some hepatoprotective effects against alcohol-induced injury in in vitro rat primary hepatocytes cell culture. This collaborate our previous observation of its hepatoprotective effect in a severe sustained 90-min hemorrhagic shock rat model.

The synthesis of higher oxides of alkali and alkaline earth metals in an electric discharge: Theoretical and experimental studies

NASA Technical Reports Server (NTRS)

Bell, A. T.; Sadhukhan, P.

1974-01-01

Potassium hydroxide was subjected to the products of an electrical discharge sustained in oxygen and produced both potassium peroxide and superoxide. The conversion to higher oxides was shown to strongly depend upon the particle size of KOH, the position of KOH in the discharge zone, and the operating conditions of the discharge. Similar experiments were performed with hydroxides of lithium and calcium which do not form superoxides, but are converted to peroxides. The yields of peroxides were shown to strongly depend upon the operating conditions of the discharge. The absence of superoxides and the presence of peroxides of lithium and calcium was explained from the consideration of relative thermodynamic stability of the oxides of lithium and calcium. Thermogravimetric analysis was shown to provide a more accurate means for determining the amount of KO2 than previous methods.

[Generation of Superoxide Radicals by Complex III in Heart Mitochondria and Antioxidant Effect of Dinitrosyl Iron Complexes at Different Partial Pressure of Oxygen].

PubMed

Dudylina, A L; Ivanova, M V; Shumaev, K B; Ruuge, E K

2016-01-01

The EPR spin-trapping technique and EPR-oximetry were used to study generation of superoxide radicals in heart mitochondria isolated from Wistar rats under conditions of variable oxygen concentration. Lithium phthalocyanine and TEMPONE-15N-D16 were chosen to determine oxygen content in a gas-permeable capillary tube containing mitochondria. TIRON was used as a spin trap. We investigated the influence of different oxygen concentrations in incubation mixture and demonstrated that heart mitochondria can generate superoxide in complex III at different partial pressure of oxygen as well as under the conditions of deep hypoxia (< 5% O2). Dinitrosyl iron complexes with glutathione (the pharmaceutical drug "Oxacom") exerted an antioxidant effect, regardless of the value of the partial pressure of oxygen, but the magnitude and kinetic characteristics of the effect depended on the concentration of the drug.

Theoretical study of the alkaline-earth metal superoxides BeO2 through SrO2

NASA Technical Reports Server (NTRS)

Bauschlicher, Charles W., Jr.; Partridge, Harry; Sodupe, Mariona; Langhoff, Stephen R.

1992-01-01

Three competing bonding mechanisms have been identified for the alkaline-earth metal superoxides: these result in a change in the optimal structure and ground state as the alkaline-earth metal becomes heavier. For example, BeO2 has a linear 3Sigma(-)g ground-state structure, whereas both CaO2 and SrO2 have C(2v)1A1 structures. For MgO2, the theoretical calculations are less definitive, as the 3A2 C(2v) structure is computed to lie only about 3 kcal/mol above the 3Sigma(-)g linear structure. The bond dissociation energies for the alkaline-earth metal superoxides have been computed using extensive Gaussian basis sets and treating electron correlation at the modified coupled-pair functional or coupled-cluster singles and doubles level with a perturbational estimate of the triple excitations.

Antiestrogenic and Anti-Inflammatory Potential of n-Hexane Fraction of Vitex negundo Linn Leaf Extract: A Probable Mechanism for Blastocyst Implantation Failure in Mus musculus.

PubMed

Jivrajani, Mehul; Ravat, Nirav; Anandjiwala, Sheetal; Nivsarkar, Manish

2014-01-01

The anti-implantation potential of different fractions of Vitex negundo Linn leaf extract was evaluated in female Swiss Albino mice. Animals from different groups were dosed orally either with 0.2% agar (vehicle) or with fractions of V. negundo leaf extract (n-hexane, chloroform, n-butanol, and remnant fractions) at 10:00 a.m., from day 1 to day 6 of pregnancy. The pregnant females from each group were sacrificed on different days of pregnancy (n = 6), and uterus was excised and used for estimation of lipid peroxidation and assay of superoxide dismutase activity as a marker for blastocyst implantation. Animals treated with n-hexane fraction showed altered level of superoxide anion radical and superoxide dismutase activity as compared to control animals. The probable mechanism by which this extract exhibits inhibition of blastocyst implantation is through the anti-inflammatory and antiestrogenic potential.

The preparation of calcium superoxide in a flowing gas stream and fluidized bed

NASA Technical Reports Server (NTRS)

Wood, P. C.; Ballou, E. V.; Spitze, L. A.; Wydeven, T.

1980-01-01

Superoxides can be used as sources of chemically stored oxygen in emergency breathing apparatus. The work reported here describes the use of a low-pressure nitrogen gas sweep through the reactant bed, for temperature control and water vapor removal. For a given set of gas temperature, bed thickness, and reaction time values, the highest purity calcium superoxide, Ca(O2)2, was obtained at the highest space velocity of the nitrogen gas sweep. The purity of the product was further increased by flow conditions that resulted in the fluidization of the reactant bed. However, scale-up of the low-pressure fluidized bed process was limited to the formation of agglomerates of reactant particles, which hindered thermal control by the flowing gas stream. A radiofrequency flow discharge inside the reaction chamber prevented agglomeration, presumably by dissipation of the static charges on the fluidized particles.

A Mitochondrial Superoxide Signal Triggers Increased Longevity in Caenorhabditis elegans

PubMed Central

Yang, Wen; Hekimi, Siegfried

2010-01-01

The nuo-6 and isp-1 genes of C. elegans encode, respectively, subunits of complex I and III of the mitochondrial respiratory chain. Partial loss-of-function mutations in these genes decrease electron transport and greatly increase the longevity of C. elegans by a mechanism that is distinct from that induced by reducing their level of expression by RNAi. Electron transport is a major source of the superoxide anion (O⋅ –), which in turn generates several types of toxic reactive oxygen species (ROS), and aging is accompanied by increased oxidative stress, which is an imbalance between the generation and detoxification of ROS. These observations have suggested that the longevity of such mitochondrial mutants might result from a reduction in ROS generation, which would be consistent with the mitochondrial oxidative stress theory of aging. It is difficult to measure ROS directly in living animals, and this has held back progress in determining their function in aging. Here we have adapted a technique of flow cytometry to directly measure ROS levels in isolated mitochondria to show that the generation of superoxide is elevated in the nuo-6 and isp-1 mitochondrial mutants, although overall ROS levels are not, and oxidative stress is low. Furthermore, we show that this elevation is necessary and sufficient to increase longevity, as it is abolished by the antioxidants NAC and vitamin C, and phenocopied by mild treatment with the prooxidant paraquat. Furthermore, the absence of effect of NAC and the additivity of the effect of paraquat on a variety of long- and short-lived mutants suggest that the pathway triggered by mitochondrial superoxide is distinct from previously studied mechanisms, including insulin signaling, dietary restriction, ubiquinone deficiency, the hypoxic response, and hormesis. These findings are not consistent with the mitochondrial oxidative stress theory of aging. Instead they show that increased superoxide generation acts as a signal in young mutant animals to trigger changes of gene expression that prevent or attenuate the effects of subsequent aging. We propose that superoxide is generated as a protective signal in response to molecular damage sustained during wild-type aging as well. This model provides a new explanation for the well-documented correlation between ROS and the aged phenotype as a gradual increase of molecular damage during aging would trigger a gradually stronger ROS response. PMID:21151885

Testing of the KRIA Ionizing Water Treatment System for Waters Contaminated with Diesel, PCBs, and Nutrients (Nitrogen Forms)

DTIC Science & Technology

2016-02-01

superoxide treatment, presumably because the radioisotopes were solubilized and rinsed off the soil. The study hypothesized that the superoxide enhanced...reservoir, Blantyre Malawi. Physics and Chemistry of the Earth 28:1161-1164. Clean Water Team (CWT). 2004. Electrical Conductivity/Salinity Fact...number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) February 2016 2. REPORT TYPE Final report 3. DATES COVERED

Fructose induced neurogenic hypertension mediated by overactivation of p38 MAPK to impair insulin signaling transduction caused central insulin resistance.

PubMed

Cheng, Pei-Wen; Lin, Yu-Te; Ho, Wen-Yu; Lu, Pei-Jung; Chen, Hsin-Hung; Lai, Chi-Cheng; Sun, Gwo-Ching; Yeh, Tung-Chen; Hsiao, Michael; Tseng, Ching-Jiunn; Liu, Chun-Peng

2017-11-01

Type 2 diabetes are at a high risk of complications related to hypertension, and reports have indicated that insulin levels may be associated with blood pressure (BP). Fructose intake has recently been reported to promote insulin resistance and superoxide formation. The aim of this study is to investigate whether fructose intake can enhance superoxide generation and impair insulin signaling in the NTS and subsequently elevate BP in rats with fructose-induced hypertension. Treatment with fructose for 4 weeks increased the BP, serum fasting insulin, glucose, homeostatic model assessment-insulin resistance, and triglyceride levels and reduced the serum direct high-density lipoprotein level in the fructose group. The Tempol treatment recovered the fructose-induced decrease in nitric oxide production in the NTS. Immunoblotting and immunofluorescence analyses further showed that fructose increased the p38- and fructose-induced phosphorylation of insulin receptor substrate 1 (IRS1 S307 ) and suppressed Akt S473 and neuronal nitric oxide synthase phosphorylation. Similarly, fructose was able to impair insulin sensitivity and increase insulin levels in the NTS. Fructose intake also increased the production of superoxide in the NTS. The results of this study suggest that fructose might induce central insulin resistance and elevate BP by enhancing superoxide production and activating p38 phosphorylation in the NTS. Copyright © 2017 Elsevier Inc. All rights reserved.

Ultraviolet-B- and ozone-induced biochemical changes in antioxidant enzymes of Arabidopsis thaliana.

PubMed Central

Rao, M V; Paliyath, G; Ormrod, D P

1996-01-01

Earlier studies with Arabidopsis thaliana exposed to ultraviolet B (UV-B) and ozone (O3) have indicated the differential responses of superoxide dismutase and glutathione reductase. In this study, we have investigated whether A. thaliana genotype Landsberg erecta and its flavonoid-deficient mutant transparent testa (tt5) is capable of metabolizing UV-B- and O3-induced activated oxygen species by invoking similar antioxidant enzymes. UV-B exposure preferentially enhanced guaiacol-peroxidases, ascorbate peroxidase, and peroxidases specific to coniferyl alcohol and modified the substrate affinity of ascorbate peroxidase. O3 exposure enhanced superoxide dismutase, peroxidases, glutathione reductase, and ascorbate peroxidase to a similar degree and modified the substrate affinity of both glutathione reductase and ascorbate peroxidase. Both UV-B and O3 exposure enhanced similar Cu,Zn-superoxide dismutase isoforms. New isoforms of peroxidases and ascorbate peroxidase were synthesized in tt5 plants irradiated with UV-B. UV-B radiation, in contrast to O3, enhanced the activated oxygen species by increasing membrane-localized NADPH-oxidase activity and decreasing catalase activities. These results collectively suggest that (a) UV-B exposure preferentially induces peroxidase-related enzymes, whereas O3 exposure invokes the enzymes of superoxide dismutase/ascorbate-glutathione cycle, and (b) in contrast to O3, UV-B exposure generated activated oxygen species by increasing NADPH-oxidase activity. PMID:8587977

Oxidative stress and maternal obesity: feto-placental unit interaction.

PubMed

Malti, N; Merzouk, H; Merzouk, S A; Loukidi, B; Karaouzene, N; Malti, A; Narce, M

2014-06-01

To determine oxidative stress markers in maternal obesity during pregnancy and to evaluate feto-placental unit interaction, especially predictors of fetal metabolic alterations. 40 obese pregnant women (prepregnancy BMI > 30 kg/m²) were compared to 50 control pregnant women. Maternal, cord blood and placenta samples were collected at delivery. Biochemical parameters (total cholesterol and triglycerides) and oxidative stress markers (malondialdehyde, carbonyl proteins, superoxide anion expressed as reduced Nitroblue Tetrazolium, nitric oxide expressed as nitrite, reduced glutathione, catalase, superoxide dismutase) were assayed by biochemical methods. Maternal, fetal and placental triglyceride levels were increased in obese group compared to control. Maternal malondialdehyde, carbonyl proteins, nitric oxide and superoxide anion levels were high while reduced glutathione concentrations and superoxide dismutase activity were low in obesity. In the placenta and in newborns of these obese mothers, variations of redox balance were also observed indicating high oxidative stress. Maternal and placental interaction constituted a strong predictor of fetal redox variations in obese pregnancies. Maternal obesity compromised placental metabolism and antioxidant status which strongly impacted fetal redox balance. Oxidative stress may be one of the key downstream mediators that initiate programming of the offspring. Maternal obesity is associated with metabolic alterations and dysregulation of redox balance in the mother-placenta - fetus unit. These perturbations could lead to maternal and fetal complications and should be carefully considered. Copyright © 2014 Elsevier Ltd. All rights reserved.

Urate as a Physiological Substrate for Myeloperoxidase

PubMed Central

Meotti, Flavia C.; Jameson, Guy N. L.; Turner, Rufus; Harwood, D. Tim; Stockwell, Samantha; Rees, Martin D.; Thomas, Shane R.; Kettle, Anthony J.

2011-01-01

Urate and myeloperoxidase (MPO) are associated with adverse outcomes in cardiovascular disease. In this study, we assessed whether urate is a likely physiological substrate for MPO and if the products of their interaction have the potential to exacerbate inflammation. Urate was readily oxidized by MPO and hydrogen peroxide to 5-hydroxyisourate, which decayed to predominantly allantoin. The redox intermediates of MPO were reduced by urate with rate constants of 4.6 × 105 m−1 s−1 for compound I and 1.7 × 104 m−1 s−1 for compound II. Urate competed with chloride for oxidation by MPO and at hyperuricemic levels is expected to be a substantive substrate for the enzyme. Oxidation of urate promoted super-stoichiometric consumption of glutathione, which indicates that it is converted to a free radical intermediate. In combination with superoxide and hydrogen peroxide, MPO oxidized urate to a reactive hydroperoxide. This would form by addition of superoxide to the urate radical. Urate also enhanced MPO-dependent consumption of nitric oxide. In human plasma, stimulated neutrophils produced allantoin in a reaction dependent on the NADPH oxidase, MPO and superoxide. We propose that urate is a physiological substrate for MPO that is oxidized to the urate radical. The reactions of this radical with superoxide and nitric oxide provide a plausible link between urate and MPO in cardiovascular disease. PMID:21266577

Mechanism of triclosan toxicity: Mitochondrial dysfunction including complex II inhibition, superoxide release and uncoupling of oxidative phosphorylation.

PubMed

Teplova, Vera V; Belosludtsev, Konstantin N; Kruglov, Alexey G

2017-06-05

Triclosan (5-chloro-2'-(2,4-dichlorophenoxy)phenol), a widely used antibacterial agent, exerts adverse effects on the organism of mammals. Recent research reviled that triclosan at low micromolar concentrations causes mitochondrial dysfunction in many cell types, but the mechanisms of its effect are not fully understood. Here we show that exposure to triclosan disrupted membrane potential, prevented the calcium uptake-driven high-amplitude mitochondrial swelling, stimulated the respiration in the presence of complex I substrates, and suppressed the ADP-stimulated respiration in the presence of complex II substrate, succinate. Triclosan directly inhibited complex II activity. Similar to the complex II inhibitor thenoyltrifluoroacetone, triclosan induced the oxidation of the cytochromes b566 and b562 and caused the release of mitochondrial superoxide. Opposite to thenoyltrifluoroacetone, triclosan increased superoxide release synergistically with myxothiazol but not with antimycin A, indicating different topology of superoxide-producing sites. We concluded that triclosan is unique by its capability of acting as both a protonophore and an unusual complex II inhibitor, which interferes with the mitochondrial respiration by blocking the electron transfer between ubiquinone at the Q d -binding site and heme b. Our data can provide an insight into the mechanisms of the carcinogenic effect of triclosan in the liver and other tissues. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular Cloning and Biochemical Characterization of the Iron Superoxide Dismutase from the Cyanobacterium Nostoc punctiforme ATCC 29133 and Its Response to Methyl Viologen-Induced Oxidative Stress.

PubMed

Moirangthem, Lakshmipyari Devi; Ibrahim, Kalibulla Syed; Vanlalsangi, Rebecca; Stensjö, Karin; Lindblad, Peter; Bhattacharya, Jyotirmoy

2015-12-01

Superoxide dismutase (SOD) detoxifies cell-toxic superoxide radicals and constitutes an important component of antioxidant machinery in aerobic organisms, including cyanobacteria. The iron-containing SOD (SodB) is one of the most abundant soluble proteins in the cytosol of the nitrogen-fixing cyanobacterium Nostoc punctiforme ATCC 29133, and therefore, we investigated its biochemical properties and response to oxidative stress. The putative SodB-encoding open reading frame Npun_R6491 was cloned and overexpressed in Escherichia coli as a C-terminally hexahistidine-tagged protein. The purified recombinant protein had a SodB specific activity of 2560 ± 48 U/mg protein at pH 7.8 and was highly thermostable. The presence of a characteristic iron absorption peak at 350 nm, and its sensitivity to H2O2 and azide, confirmed that the SodB is an iron-containing SOD. Transcript level of SodB in nitrogen-fixing cultures of N. punctiforme decreased considerably (threefold) after exposure to an oxidative stress-generating herbicide methyl viologen for 4 h. Furthermore, in-gel SOD activity analysis of such cultures grown at increasing concentrations of methyl viologen also showed a loss of SodB activity. These results suggest that SodB is not the primary scavenger of superoxide radicals induced by methyl viologen in N. punctiforme.

Study on the Protective Effect of a New Manganese Superoxide Dismutase on the Microvilli of Rabbit Eyes Exposed to UV Radiation.

PubMed

Grumetto, Lucia; Del Prete, Antonio; Ortosecco, Giovanni; Barbato, Francesco; Del Prete, Salvatore; Borrelli, Antonella; Schiattarella, Antonella; Mancini, Roberto; Mancini, Aldo

2015-01-01

We present a study on the protective effects against UV radiation of a gel formulation containing a new recombinant form of manganese superoxide dismutase on the conjunctiva and corneal epithelia of rabbit eyes. The integrity of the microvilli of both ocular tissues has been considered as an indicator of the health of the tissues. Samples, collected by impression cytology technique, were added of 80 µL of a gel formulation containing superoxide dismutase (2.0 µg/mL) and irradiated with UV rays for 30 minutes and were evaluated with scanning electron microscopy. Wilcoxon test was used to verify the possible occurrence of statistically significant differences between damage for treated and nontreated tissues. Application of gel produces a significant reduction of damage by UV irradiation of ocular epithelia; both epithelia present a significant reduction of damaged microvilli number if treated with the superoxide dismutase gel formulation: the p values (differences between damage found for treated and nontreated both ocular tissues) for conjunctiva and cornea samples were p ≪ 0.01 and p ≪ 0.0001, respectively, at confidence level of 95%. The administration of this gel formulation before UV exposure plays a considerable protective role in ocular tissues of rabbit eye with a significant reduction of the damage.

Mitochondrial Respiratory Chain Inhibitors Involved in ROS Production Induced by Acute High Concentrations of Iodide and the Effects of SOD as a Protective Factor

PubMed Central

Wang, Lingyan; Duan, Qi; Wang, Tingting; Ahmed, Mohamed; Zhang, Na; Li, Yongmei; Li, Lanying; Yao, Xiaomei

2015-01-01

A major source of reactive oxygen species (ROS) generation is the mitochondria. By using flow cytometry of the mitochondrial fluorescent probe, MitoSOX Red, western blot of mitochondrial ROS scavenger Peroxiredoxin (Prx) 3 and fluorescence immunostaining, ELISA of cleaved caspases 3 and 9, and TUNEL staining, we demonstrated that exposure to 100 μM KI for 2 hours significantly increased mitochondrial superoxide production and Prx 3 protein expression with increased expressions of cleaved caspases 3 and 9. Besides, we indicated that superoxide dismutase (SOD) at 1000 unit/mL attenuated the increase in mitochondrial superoxide production, Prx 3 protein expression, and lactate dehydrogenase (LDH) release and improved the relative cell viability at 100 μM KI exposure. However, SOD inhibitor diethyldithiocarbamic acid (DETC) (2 mM), Rotenone (0.5 μM), a mitochondrial complex I inhibitor, and Antimycin A (10 μM), a complex III inhibitor, caused an increase in mitochondrial superoxide production, Prx 3 protein expression, and LDH release and decreased the relative cell viability. We conclude that the inhibitors of mitochondrial respiratory chain complex I or III may be involved in oxidative stress caused by elevated concentrations of iodide, and SOD demonstrates its protective effect on the Fischer rat thyroid cell line (FRTL) cells. PMID:26294939

Metallothionein-I/II Knockout Mice Aggravate Mitochondrial Superoxide Production and Peroxiredoxin 3 Expression in Thyroid after Excessive Iodide Exposure

PubMed Central

Zhang, Na; Wang, Lingyan; Duan, Qi; Lin, Laixiang; Ahmed, Mohamed; Wang, Tingting; Yao, Xiaomei

2015-01-01

Purpose. We aim to figure out the effect of metallothioneins on iodide excess induced oxidative stress in the thyroid. Methods. Eight-week-old MT-I/II knockout (MT-I/II KO) mice and background-matched wild-type (WT) mice were used. Mitochondrial superoxide production and peroxiredoxin (Prx) 3 expression were measured. Results. In in vitro study, more significant increases in mitochondrial superoxide production and Prx 3 expression were detected in the MT-I/II KO groups. In in vivo study, significantly higher concentrations of urinary iodine level were detected in MT-I/II KO mice in 100 HI group. Compared to the NI group, there was no significant difference existing in serum thyroid hormones level in either groups (P > 0.05), while the mitochondrial superoxide production was significantly increased in 100 HI groups with significantly increased LDH activity and decreased relative cell viability. Compared to WT mice, more significant changes were detected in MT-I/II KO mice in 100 HI groups. No significant differences were detected between the NI group and 10 HI group in both the MT-I/II KO and WT mice groups (P > 0.05). Conclusions. Iodide excess in a thyroid without MT I/II protection may result in strong mitochondrial oxidative stress, which further leads to the damage of thyrocytes. PMID:26101557

Dietary copper supplements modulate aortic superoxide dismutase, nitric oxide and atherosclerosis.

PubMed

Lamb, David J; Tickner, Michelle L; Hourani, Susanna M O; Ferns, Gordon A A

2005-08-01

The objective was to test the hypothesis that dietary copper inhibits atherosclerosis by inducing superoxide dismutase (SOD) and potentiating nitric oxide (NO). New Zealand White rabbits were fed either a cholesterol diet (n = 8) or a cholesterol diet containing 0.02% copper acetate (n = 8) for 13 weeks. We found that the intimal area was significantly smaller in the animals supplemented with copper (P < 0.005), although integrated plasma cholesterol levels were not significantly different. This was associated with a significant increase in aortic copper content (P < 0.05), SOD activity (P < 0.05) and Cu/Zn SOD mRNA (P < 0.05) and a significant decrease in nitrotyrosine content (P < 0.05). Furthermore, there was a positive correlation between aortic copper content and SOD activity (P < 0.005, R(2) = 0.83) and a negative correlation between aortic superoxide dimutase activity and nitrotyrosine content (P < 0.005, R(2) = 0.93). In organ bath experiments, the relaxation of precontracted carotid artery rings to calcium ionophore was greater in animals supplemented with copper. No difference in response to sodium nitroprusside was observed. These data suggest that in the cholesterol-fed rabbit, copper supplements inhibit the progression of atherosclerosis by increasing SOD expression, thereby reducing the interaction of NO with superoxide, and hence potentiating NO-mediated pathways that may protect against atherosclerosis.

Soy isoflavone supplementation elevates erythrocyte superoxide dismutase, but not plasma ceruloplasmin in postmenopausal breast cancer survivors.

PubMed

DiSilvestro, Robert A; Goodman, Jaime; Dy, Emily; Lavalle, Gregory

2005-02-01

Soy isoflavone antioxidant effects may help prevent breast cancer re-occurrence, but isoflavone estrogen-like actions may increase breast cancer risk. These isoflavone actions can be reflected by effects on two copper enzymes activities, superoxide dismutase 1 (SOD 1), which has antioxidant function relevant to breast cancer prevention, and ceruloplasmin, which has its synthesis up-regulated by estrogen, and for which high values are associated with high breast cancer risk. A soy isoflavone-rich concentrate supplement was examined for effects on these two copper enzyme activities in post-menopausal breast cancer survivors (n = 7) in a crossover design with a placebo (24 days on supplement or placebo; 14 day wash out). The soy concentrate, but not the placebo, increased erythrocyte SOD 1 activities, but not ceruloplasmin activities or protein. The effect on superoxide dismutase activities was not likely due to increased copper intake since analysis of the soy extract showed little copper. The effect on superoxide dismutase was not accompanied by a change in urinary contents of 8-deoxyhydroxyguanosine, a DNA oxidant product, though perhaps this would change with a longer intervention. In summary, in regard to two copper enzyme activities, an isoflavone-rich soy concentrate showed an antioxidant effect considered relevant to breast cancer, but not an effect associated with estrogenic activity and increased breast cancer risk.

Losartan Improves Impaired Nitric Oxide Synthase-Dependent Dilatation of Cerebral Arterioles in Type 1 Diabetic Rats

PubMed Central

Arrick, Denise M.; Sharpe, Glenda M.; Sun, Hong; Mayhan, William G.

2009-01-01

We examined whether activation of angiotensin-1 receptors (AT1R) could account for impaired responses of cerebral arterioles during Type 1 diabetes (T1D). First, we measured responses of cerebral arterioles in nondiabetic rats to eNOS-dependent (acetylcholine and adenosine diphosphate (ADP)) and -independent (nitroglycerin) agonists before and during application of angiotensin II. Next, we examined whether losartan could improve impaired responses of cerebral arterioles during T1D. In addition, we harvested cerebral microvessels for Western blot analysis of AT1R protein and measured production of superoxide anion by brain tissue under basal conditions and in response to angiotensin II in the absence or presence of losartan. We found that angiotensin II specifically impaired eNOS-dependent reactivity of cerebral arterioles. In addition, while losartan did not alter responses in nondiabetics, losartan restored impaired eNOS-dependent vasodilatation in diabetics. Further, AT1R protein was higher in diabetics compared to nondiabetics. Finally, superoxide production was higher in brain tissue from diabetics compared to nondiabetics under basal conditions, angiotensin II increased superoxide production in nondiabetics and diabetics, and losartan decreased basal (diabetics) and angiotensin II-induced production of superoxide (nondiabetics and diabetics). We suggest that activation of AT1R during T1D plays a critical role in impaired eNOS-dependent dilatation of cerebral arterioles. PMID:18400212

Dietary copper supplements modulate aortic superoxide dismutase, nitric oxide and atherosclerosis

PubMed Central

Lamb, David J; Tickner, Michelle L; Hourani, Susanna M O; Ferns, Gordon A A

2005-01-01

The objective was to test the hypothesis that dietary copper inhibits atherosclerosis by inducing superoxide dismutase (SOD) and potentiating nitric oxide (NO). New Zealand White rabbits were fed either a cholesterol diet (n = 8) or a cholesterol diet containing 0.02% copper acetate (n = 8) for 13 weeks. We found that the intimal area was significantly smaller in the animals supplemented with copper (P < 0.005), although integrated plasma cholesterol levels were not significantly different. This was associated with a significant increase in aortic copper content (P < 0.05), SOD activity (P < 0.05) and Cu/Zn SOD mRNA (P < 0.05) and a significant decrease in nitrotyrosine content (P < 0.05). Furthermore, there was a positive correlation between aortic copper content and SOD activity (P < 0.005, R2 = 0.83) and a negative correlation between aortic superoxide dimutase activity and nitrotyrosine content (P < 0.005, R2 = 0.93). In organ bath experiments, the relaxation of precontracted carotid artery rings to calcium ionophore was greater in animals supplemented with copper. No difference in response to sodium nitroprusside was observed. These data suggest that in the cholesterol-fed rabbit, copper supplements inhibit the progression of atherosclerosis by increasing SOD expression, thereby reducing the interaction of NO with superoxide, and hence potentiating NO-mediated pathways that may protect against atherosclerosis. PMID:16045547

Tocotrienol Rich Palm Oil Extract Is More Effective Than Pure Tocotrienols at Improving Endothelium-Dependent Relaxation in the Presence of Oxidative Stress

PubMed Central

Ali, Saher F.; Woodman, Owen L.

2015-01-01

Oxidative endothelial dysfunction is a critical initiator of vascular disease. Vitamin E is an effective antioxidant but attempts to use it to treat vascular disorders have been disappointing. This study investigated whether tocotrienols, the less abundant components of vitamin E compared to tocopherols, might be more effective at preserving endothelial function. Superoxide generated by hypoxanthine/xanthine oxidase or rat aorta was measured using lucigenin-enhanced chemiluminescence. The effect of α-tocopherol, α-, δ-, and γ-tocotrienols and a tocotrienol rich palm oil extract (tocomin) on levels of superoxide was assessed. Endothelial function in rat aorta was assessed in the presence of the auto-oxidant pyrogallol. Whilst all of the compounds displayed antioxidant activity, the tocotrienols were more effective when superoxide was produced by hypoxanthine/xanthine oxidase whereas tocomin and α-tocopherol were more effective in the isolated aorta. Tocomin and α-tocopherol restored endothelial function in the presence of oxidant stress but α-, δ-, and γ-tocotrienols were ineffective. The protective effect of tocomin was replicated when the tocotrienols were present with, but not without, α-tocopherol. Tocotrienol rich tocomin is more effective than α-tocopherol at reducing oxidative stress and restoring endothelium-dependent relaxation in rat aortae and although α-, δ-, and γ-tocotrienols effectively scavenged superoxide, they did not improve endothelial function. PMID:26075031

Extracellular superoxide dismutase is necessary to maintain renal blood flow during sepsis development.

PubMed

Constantino, Larissa; Galant, Letícia Selinger; Vuolo, Francieli; Guarido, Karla Lorena; Kist, Luiza Wilges; de Oliveira, Giovanna Medeiros Tavares; Pasquali, Matheus Augusto de Bittencourt; de Souza, Cláudio Teodoro; da Silva-Santos, José Eduardo; Bogo, Maurício Reis; Moreira, José Cláudio Fonseca; Ritter, Cristiane; Dal-Pizzol, Felipe

2017-12-01

Extracellular superoxide dismutase (ECSOD) protects nitric oxide (NO) bioavailability by decreasing superoxide levels and preventing peroxynitrite generation, which is important in maintaining renal blood flow and in preventing acute kidney injury. However, the profile of ECSOD expression after sepsis is not fully understood. Therefore, we intended to evaluate the content and gene expression of superoxide dismutase (SOD) isoforms in the renal artery and their relation to renal blood flow. Sepsis was induced in Wistar rats by caecal ligation and perforation. Several times after sepsis induction, renal blood flow (12, 24 and 48 h); the renal arterial content of SOD isoforms, nitrotyrosine, endothelial and inducible nitric oxide synthase (e-NOS and i-NOS), and phosphorylated vasodilator-stimulated phosphoprotein (pVASP); and SOD activity (3, 6 and 12 h) were measured. The influence of a SOD inhibitor was also evaluated. An increase in ECSOD content was associated with decreased 3-nitrotyrosine levels. These events were associated with an increase in pVASP content and maintenance of renal blood flow. Moreover, previous treatment with a SOD inhibitor increased nitrotyrosine content and reduced renal blood flow. ECSOD appears to have a major role in decreasing peroxynitrite formation in the renal artery during the early stages of sepsis development, and its application can be important in renal blood flow control and maintenance during septic insult.

Effect of hypoxia mimetic cobalt chloride on the expression of extracellular-superoxide dismutase in retinal pericytes.

PubMed

Adachi, Tetsuo; Aida, Kazunari; Nishihara, Hiroko; Kamiya, Tetsuro; Hara, Hirokazu

2011-01-01

The initial clinical stage of diabetic retinopathy (DR) is characterized by the development of intraretinal microvascular abnormalities. The increased formation of reactive oxygen species (ROS) is thought to be a key event in the pathogenesis of DR. Extracellular-superoxide dismutase (EC-SOD) is an anti-inflammatory enzyme that is distributed mainly in vascular cells and protects cells from ROS by scavenging superoxide anion. Treatment with cobalt chloride (CoCl(2)) decreased the expression of EC-SOD but not other SOD isozymes in pericytes accompanied with an increase of intracellular ROS production. Pre-treatment with N-acetylcysteine (NAC) significantly suppressed the ROS production and down-regulation of EC-SOD. We observed the activation of caspase-3 and DNA fragmentation as signs of apoptotic process by CoCl(2) treatment. In addition, these phenomena were significantly inhibited by pre-treatment with NAC. EC-SOD enhancer 4-phenyl butyric acid also suppressed the caspase-3 activation. It is known that the presence of a high level of EC-SOD throughout the vessel walls might have an important protective role against superoxide in the vascular system. The decrease in EC-SOD expression accompanied with elevation of ROS level in pericytes under hypoxia might induce and/or promote the ROS-triggered apoptosis of pericytes and the development of pathogenesis in DR.

The effects of caffeic, coumaric and ferulic acids on proliferation, superoxide production, adhesion and migration of human tumor cells in vitro.

PubMed

Nasr Bouzaiene, Nouha; Kilani Jaziri, Soumaya; Kovacic, Hervé; Chekir-Ghedira, Leila; Ghedira, Kamel; Luis, José

2015-11-05

Reactive oxygen species are well-known mediators of various biological responses. In this study, we examined the effect of three phenolic acids, caffeic, coumaric and ferulic acids, on superoxide anion production, adhesion and migration of human lung (A549) and colon adenocarcinoma (HT29-D4) cancer cell lines. Proliferation of both tumor cells was inhibited by phenolic acids. Caffeic, coumaric and ferulic acids also significantly inhibited superoxide production in A549 and HT29-D4 cells. Superoxide anion production decreased by 92% and 77% at the highest tested concentration (200 µM) of caffeic acid in A549 and HT29-D4 cell lines respectively. Furthermore, A549 and HT29-D4 cell adhesion was reduced by 77.9% and 79.8% respectively at the higher tested concentration of ferulic acid (200 µM). Migration assay performed towards A549 cell line, revealed that tested compounds reduced significantly cell migration. At the highest concentration tested (200 µM), the covered surface was 7.7%, 9.5% and 35% for caffeic, coumaric or ferulic acids, respectively. These results demonstrate that caffeic, coumaric and ferulic acids may participate as active ingredients in anticancer agents against lung and colon cancer development, at adhesion and migration steps of tumor progression. Copyright © 2015 Elsevier B.V. All rights reserved.

Microchip electrophoresis with laser-induced fluorescence detection for the determination of the ratio of nitric oxide to superoxide production in macrophages during inflammation.

PubMed

Caruso, Giuseppe; Fresta, Claudia G; Siegel, Joseph M; Wijesinghe, Manjula B; Lunte, Susan M

2017-07-01

It is well known that excessive production of reactive oxygen and nitrogen species is linked to the development of oxidative stress-driven disorders. In particular, nitric oxide (NO) and superoxide (O 2 •- ) play critical roles in many physiological and pathological processes. This article reports the use of 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate and MitoSOX Red in conjunction with microchip electrophoresis and laser-induced fluorescence detection for the simultaneous detection of NO and O 2 •- in RAW 264.7 macrophage cell lysates following different stimulation procedures. Cell stimulations were performed in the presence and absence of cytosolic (diethyldithiocarbamate) and mitochondrial (2-methoxyestradiol) superoxide dismutase (SOD) inhibitors. The NO/O 2 •- ratios in macrophage cell lysates under physiological and proinflammatory conditions were determined. The NO/O 2 •- ratios were 0.60 ± 0.07 for unstimulated cells pretreated with SOD inhibitors, 1.08 ± 0.06 for unstimulated cells in the absence of SOD inhibitors, and 3.14 ± 0.13 for stimulated cells. The effect of carnosine (antioxidant) or Ca 2+ (intracellular messenger) on the NO/O 2 •- ratio was also investigated. Graphical Abstract Simultaneous detection of nitric oxide and superoxide in macrophage cell lysates.

Tocotrienol Rich Palm Oil Extract Is More Effective Than Pure Tocotrienols at Improving Endothelium-Dependent Relaxation in the Presence of Oxidative Stress.

PubMed

Ali, Saher F; Woodman, Owen L

2015-01-01

Oxidative endothelial dysfunction is a critical initiator of vascular disease. Vitamin E is an effective antioxidant but attempts to use it to treat vascular disorders have been disappointing. This study investigated whether tocotrienols, the less abundant components of vitamin E compared to tocopherols, might be more effective at preserving endothelial function. Superoxide generated by hypoxanthine/xanthine oxidase or rat aorta was measured using lucigenin-enhanced chemiluminescence. The effect of α-tocopherol, α-, δ-, and γ-tocotrienols and a tocotrienol rich palm oil extract (tocomin) on levels of superoxide was assessed. Endothelial function in rat aorta was assessed in the presence of the auto-oxidant pyrogallol. Whilst all of the compounds displayed antioxidant activity, the tocotrienols were more effective when superoxide was produced by hypoxanthine/xanthine oxidase whereas tocomin and α-tocopherol were more effective in the isolated aorta. Tocomin and α-tocopherol restored endothelial function in the presence of oxidant stress but α-, δ-, and γ-tocotrienols were ineffective. The protective effect of tocomin was replicated when the tocotrienols were present with, but not without, α-tocopherol. Tocotrienol rich tocomin is more effective than α-tocopherol at reducing oxidative stress and restoring endothelium-dependent relaxation in rat aortae and although α-, δ-, and γ-tocotrienols effectively scavenged superoxide, they did not improve endothelial function.

Redox Regulation of the Superoxide Dismutases SOD3 and SOD2 in the Pulmonary Circulation.

PubMed

Hernandez-Saavedra, Daniel; Swain, Kalin; Tuder, Rubin; Petersen, Steen V; Nozik-Grayck, Eva

2017-01-01

When evaluating the role of redox-regulating signaling in pulmonary vascular diseases, it is intriguing to consider the modulation of key antioxidant enzymes like superoxide dismutase (SOD) because SOD isoforms are regulated by redox reactions, and, in turn, modulate downstream redox sensitive processes. The emerging field of redox biology is built upon understanding the regulation and consequences of tightly controlled and specific reduction-oxidation reactions that are critical for diverse cellular processes including cell signaling. Of relevance, both the site of production of specific reactive oxygen and nitrogen species and the site of the antioxidant defenses are highly compartmentalized within the cell. For example, superoxide is generated during oxidative phosphorylation in the mitochondria as well as by a number of enzymatic sources within the cytosol and at the cell membrane. In the pulmonary circulation, these sources include the mitochondrial electron transport chain, NADPH oxidases (NOX1-4, Duox1,2), nitric oxide synthases, and xanthine oxidase; this important topic has been thoroughly reviewed recently [1]. In parallel with these different cellular sites of superoxide production, the three SOD isoforms are also specifically localized to the cytosol (SOD1), mitochondria (SOD2) or extracellular compartment (SOD3). This chapter focuses on the role of redox mechanisms regulating SOD2 and SOD3, with an emphasis on these processes in the setting of pulmonary hypertension.

Synthetic nickel-containing superoxide dismutase attenuates para-phenylenediamine-induced bladder dysfunction in rats

PubMed Central

Chiang, Bing-Juin; Chen, Tien-Wen; Chung, Shiu-Dong; Lee, Way-Zen; Chien, Chiang-Ting

2017-01-01

Para (p)-phenylenediamine and its toxic metabolites induce excess reactive oxygen species formation that results in bladder voiding dysfunction. We determined the effects of synthetic Ni-containing superoxide dismutase mimics and the role of oxidative stress in p-phenylenediamine-induced urinary bladder dysfunction. P-phenylenediamine (60 μg/kg/day) was intraperitoneally administered for 4 weeks to induce bladder injury in female Wistar rats. Synthetic Ni-containing superoxide dismutase mimics, WCT003 (1.5 mg/kg) and WCT006 (1.5 mg/kg), were then intraperitoneally administered for 2 weeks. Transcystometrograms were performed in urethane-anesthetized rats. The in vitro and in vivo reactive oxygen species levels and pathological changes in formalin-fixed bladder sections were evaluated. Western blotting and immunohistochemistry elucidated the pathophysiological mechanisms of oxidative stress-induced apoptosis, autophagy, and pyroptosis. P-phenylenediamine increased voiding frequency, blood and urinary bladder levels of reactive oxygen species, and neutrophil and mast cell infiltration. It also upregulated biomarkers of autophagy (LC3 II), apoptosis (poly (ADP-ribose) polymerase), and pyroptosis (Caspase 1). WCT003 and WCT006 ameliorated reactive oxygen species production, inflammation, apoptosis, autophagy, pyroptosis, and bladder hyperactivity. P-phenylenediamine increased oxidative stress, inflammatory leukocytosis, autophagy, apoptosis, and pyroptosis formation within the urinary bladder. Novel synthetic nickel-containing superoxide dismutase mimics relieved p-phenylenediamine-induced bladder inflammation and voiding dysfunction. PMID:29285288

Synergistic effect of co-exposure to cadmium (II) and 4-n-nonylphenol on growth inhibition and oxidative stress of Chlorella sorokiniana.

PubMed

Wang, Lu; Kang, Yuan; Liang, Siyun; Chen, Danying; Zhang, Qiuyun; Zeng, Lixuan; Luo, Jiwen; Jiang, Feng

2018-06-15

Toxicological effect of freshwater algae co-exposure to Cd and 4-n-nonylphenol (4-n-NP) was seldom reported. In the present study, Chlorella sorokiniana was selected for testing the single and combined effect of Cd and 4-n-NP by detecting the growth inhibition and oxidative stress after exposure for 48 h, 72 h, and 96 h. The combined effects were evaluated by using toxic units (TU) method and concentration addition（CA）model. The synergistic effect of mixture on algal growth inhibition was both observed at 48 h and 72 h, and the additive effect was observed at 96 h. In addition, the significant alterations of superoxide, thiobarbituric acid reactive substances and antioxidant defenses (superoxide dismutase, catalase, glutathione) have been detected. It could be observed that the mixture predominantly lead to synergistic effects in superoxide induction, and the antagonistic effects in the GSH induction. A similar trend between the superoxide induction and growth inhibition were observed, which may indicate that the oxidative effects of Chlorella sorokiniana contributed to the growth inhibition after exposure to Cd and 4-n-NP. These findings may have important implications in the risk assessments of heavy metals and endocrine disruptors in the aquatic environment. Copyright © 2018 Elsevier Inc. All rights reserved.

General method for site-directed mutagenesis in Escherichia coli O18ac:K1:H7: deletion of the inducible superoxide dismutase gene, sodA, does not diminish bacteremia in neonatal rats.

PubMed

Bloch, C A; Thorne, G M; Ausubel, F M

1989-07-01

A defined deletion in the Escherichia coli K-12 sodA gene (encoding manganese-superoxide dismutase) linked to a nontransposable selectable marker was generated by transposon Tn5 insertion in combination with in vitro mutagenesis. This mutant allele was used to replace the wild-type sodA gene in an E. coli clinical isolate of serotype O18ac:K1:H7 by bacteriophage P1 transduction. The O18ac:K1:H7 sodA mutant contained no manganese-superoxide dismutase and no hybrid manganese-iron-superoxide dismutase. The sodA mutant was more sensitive to paraquat toxicity than were the parental strain and an isogenic mutant bearing an analogously constructed sodA+ Tn5 insertion allele. In a suckling rat model for bacteremia following oral inoculation of E. coli K1, the sodA mutant was undiminished in its capabilities both to colonize the gastrointestinal tract and, surprisingly, to cause bacteremia. In conjunction with the rat model for E. coli K1 pathogenesis, the method for site-directed mutagenesis described in this paper permits determination of the role played in colonization and bacteremia by any K1 gene which either has a homolog in E. coli K-12 or can be cloned and manipulated therein.

Lucigenin-dependent chemiluminescence in articular chondrocytes.

PubMed

Rathakrishnan, C; Tiku, M L

1993-08-01

We were recently able to measure intracellular levels of hydrogen peroxide within normal articular chondrocytes using the trapped indicator 2',7'-dichlorofluorescein diacetate. Further studies have shown that stimulated chondrocytes produce luminol-dependent chemiluminescence, suggesting that these cells produce hydrogen peroxide and singlet oxygen. In the present study, we have investigated the lucigenin-dependent chemiluminescence response in normal articular chondrocytes. Chondrocytes either in suspension or adhered to cover slips showed lucigenin-dependent chemiluminescence. There was a dose-dependent increase in chemiluminescence response when chondrocytes were incubated with soluble stimuli like phorbol-myristate-acetate, concanavalin A, and f-met-leu-phe. Catalase and the metabolic inhibitor, sodium azide, which inhibits the enzyme myeloperoxidase, had no inhibitory effect on lucigenin-dependent chemiluminescence production. Only the antioxidant, superoxide dismutase, prevented lucigenin-dependent chemiluminescence, indicating that this assay measures the production of superoxide anions by chondrocytes. We confirmed that chondrocytes release superoxide radicals using the biochemical assay of ferricytochrome c reduction. Since cartilage tissue is semi-transparent, we were able to measure chemiluminescence response in live cartilage tissue, showing that chondrocytes which are embedded within the matrix can also generate superoxide anion radicals. Reactive oxygen intermediates have been shown to play a significant role in the degradation of matrix in arthritis. Our previous and present studies suggest that oxygen radicals produced by chondrocytes may be an important mechanism by which chondrocytes induce cartilage matrix degradation.

Oxidized Low-Density Lipoprotein-Activated c-Jun NH2-Terminal Kinase Regulates Manganese Superoxide Dismutase Ubiquitination

PubMed Central

Takabe, Wakako; Li, Rongsong; Ai, Lisong; Yu, Fei; Berliner, Judith A.; Hsiai, Tzung K.

2012-01-01

Objective Oxidized low-density lipoprotein (oxLDL) modulates intracellular redox status and induces apoptosis in endothelial cells. However, the signal pathways and molecular mechanism remain unknown. In this study, we investigated the role of manganese superoxide dismutase (Mn-SOD) on oxLDL-induced apoptosis via c-Jun NH2-terminal kinase (JNK)-mediated ubiquitin/proteasome pathway. Methods and Results OxLDL induced JNK phosphorylation that peaked at 30 minutes in human aortic endothelial cells. Fluorescence-activated cell sorting analysis revealed that oxLDL increased mitochondrial superoxide production by 1.88±0.19-fold and mitochondrial membrane potential by 18%. JNK small interference RNA (siJNK) reduced oxLDL-induced mitochondrial superoxide production by 88.4% and mitochondrial membrane potential by 61.7%. OxLDL did not affect Mn-SOD mRNA expression, but it significantly reduced Mn-SOD protein level, which was restored by siJNK. Immunoprecipitation by ubiquitin antibody revealed that oxLDL increased ubiquitination of Mn-SOD, which was inhibited by siJNK. OxLDL-induced caspase-3 activities were also attenuated by siJNK but were enhanced by Mn-SOD small interfering RNA. Furthermore, overexpression of Mn-SOD abrogated oxLDL-induced caspase-3 activities. Conclusion OxLDL-induced JNK activation regulates mitochondrial redox status and Mn-SOD protein degradation via JNK-dependent ubiquitination, leading to endothelial cell apoptosis. PMID:20139358

Superoxide reductase from the syphilis spirochete Treponema pallidum: crystallization and structure determination using soft X-rays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Santos-Silva, Teresa; Trincão, José; Carvalho, Ana L.

2005-11-01

Superoxide reductase is a non-haem iron-containing protein involved in resistance to oxidative stress. The oxidized form of the protein has been crystallized and its three-dimensional structure solved. A highly redundant X-ray diffraction data set was collected on a rotating-anode generator using Cu Kα X-ray radiation. Four Fe atoms were located in the asymmetric unit corresponding to four protein molecules arranged as a dimer of homodimers. Superoxide reductase is a 14 kDa metalloprotein containing a catalytic non-haem iron centre [Fe(His){sub 4}Cys]. It is involved in defence mechanisms against oxygen toxicity, scavenging superoxide radicals from the cell. The oxidized form of Treponemamore » pallidum superoxide reductase was crystallized in the presence of polyethylene glycol and magnesium chloride. Two crystal forms were obtained depending on the oxidizing agents used after purification: crystals grown in the presence of K{sub 3}Fe(CN){sub 6} belonged to space group P2{sub 1} (unit-cell parameters a = 60.3, b = 59.9, c = 64.8 Å, β = 106.9°) and diffracted beyond 1.60 Å resolution, while crystals grown in the presence of Na{sub 2}IrCl{sub 6} belonged to space group C2 (a = 119.4, b = 60.1, c = 65.6 Å, β = 104.9°) and diffracted beyond 1.55 Å. A highly redundant X-ray diffraction data set from the C2 crystal form collected on a copper rotating-anode generator (λ = 1.542 Å) clearly defined the positions of the four Fe atoms present in the asymmetric unit by SAD methods. A MAD experiment at the iron absorption edge confirmed the positions of the previously determined iron sites and provided better phases for model building and refinement. Molecular replacement using the P2{sub 1} data set was successful using a preliminary trace as a search model. A similar arrangement of the four protein molecules could be observed.« less

Mitochondrial superoxide and coenzyme Q in insulin-deficient rats: increased electron leak

PubMed Central

Herlein, Judith A.; Fink, Brian D.; Henry, Dorlyne M.; Yorek, Mark A.; Teesch, Lynn M.

2011-01-01

Mitochondrial superoxide is important in the pathogeneses of diabetes and its complications. However, there is uncertainty regarding the intrinsic propensity of mitochondria to generate this radical. Studies to date suggest that superoxide production by mitochondria of insulin-sensitive target tissues of insulin-deficient rodents is reduced or unchanged. Moreover, little is known of the role of the Coenzyme Q (CoQ), whose semiquinone form reacts with molecular oxygen to generate superoxide. We measured reactive oxygen species (ROS) production, respiratory parameters, and CoQ content in mitochondria from gastrocnemius muscle of control and streptozotocin (STZ)-diabetic rats. CoQ content did not differ between mitochondria isolated from vehicle- or STZ-treated animals. CoQ also was unaffected by weight loss in the absence of diabetes (induced by caloric restriction). Under state 4 or state 3 conditions, both respiration and ROS release were reduced in diabetic mitochondria fueled with succinate, glutamate plus malate, or with all three substrates (continuous TCA cycle). However, H2O2 and directly measured superoxide production were substantially increased in gastrocnemius mitochondria of diabetic rats when expressed per unit oxygen consumed. On the basis of substrate and inhibitor effects, the mechanism involved multiple electron transport sites. More limited results using heart mitochondria were similar. ROS per unit respiration was greater in muscle mitochondria from diabetic compared with control rats during state 3, as well as state 4, while the reduction in ROS per unit respiration on transition to state 3 was less for diabetic mitochondria. In summary, ROS production is, in fact, increased in mitochondria from insulin-deficient muscle when considered relative to electron transport. This is evident on multiple energy substrates and in different respiratory states. CoQ is not reduced in diabetic mitochondria or with weight loss due to food restriction. The implications of these findings are discussed. PMID:21940403

Higher macrophage superoxide anion production in coronary artery disease (CAD) patients with Type D personality.

PubMed

Zuccarella-Hackl, Claudia; von Känel, Roland; Thomas, Livia; Kuebler, Peggy; Schmid, Jean-Paul; Mattle, Heinrich P; Mono, Marie-Louise; Rieben, Robert; Wiest, Roland; Wirtz, Petra H

2016-06-01

Type D personality (Type D) is an independent psychosocial risk factor for poor cardiac prognosis and increased mortality in patients with cardiovascular disease (CVD), but the involved mechanisms are poorly understood. Macrophages play a pivotal role in atherosclerosis, the process underlying coronary artery disease (CAD). We investigated macrophage superoxide anion production in production in CAD patients with and without Type D. We studied 20 male CAD patients with Type D (M:66.7±9.9years) and 20 age-matched male CAD patients without Type D (M:67.7±8.5years). Type D was measured using the DS14 questionnaire with the two subscales 'negative affectivity' and 'social inhibition'. We assessed macrophage superoxide anion production using the WST-1 assay. All analyses were controlled for potential confounders. CAD patients with Type D showed higher superoxide anion production compared to CAD patients without Type D (F(1,38)=15.57, p<0.001). Complementary analyses using the Type D subscales 'negative affectivity' and 'social inhibition', and their interaction as continuous measures, showed that both Type D subscales (negative affectivity: (ß=0.48, p=0.002, R(2)=0.227); social inhibition: (ß=0.46, p=0.003, R(2)=0.208)) and their interaction (ß=0.36, p=0.022, R(2)=0.130) were associated with higher WST-1 reduction scores. Results remained significant when controlling for classical CVD risk factors (i.e. body mass index, mean arterial blood pressure), atherosclerosis severity (i.e. intima media thickness, presence of carotid plaques), and psychological factors (depressive symptom severity, chronic stress). Our results indicate higher macrophage superoxide anion production in CAD patients with Type D compared to those without Type D. This may suggest a mechanism contributing to increased morbidity and mortality in CAD patients with Type D. Copyright © 2016 Elsevier Ltd. All rights reserved.

Contrasting Sensitivities of Escherichia coli Aconitases A and B to Oxidation and Iron Depletion

PubMed Central

Varghese, Shery; Tang, Yue; Imlay, James A.

2003-01-01

Superoxide damages dehydratases that contain catalytic [4Fe-4S]2+ clusters. Aconitases are members of that enzyme family, and previous work showed that most aconitase activity is lost when Escherichia coli is exposed to superoxide stress. More recently it was determined that E. coli synthesizes at least two isozymes of aconitase, AcnA and AcnB. Synthesis of AcnA, the less-abundant enzyme, is positively controlled by SoxS, a protein that is activated in the presence of superoxide-generating chemicals. We have determined that this arrangement exists because AcnA is resistant to superoxide in vivo. Surprisingly, purified AcnA is extremely sensitive to superoxide and other chemical oxidants unless it is combined with an uncharacterized factor that is present in cell extracts. In contrast, AcnB is highly sensitive to a variety of chemical oxidants in vivo, in extracts, and in its purified form. Thus, the induction of AcnA during oxidative stress provides a mechanism to circumvent a block in the tricarboxylic acid cycle. AcnA appears to be as catalytically competent as AcnB, so the retention of the latter as the primary housekeeping enzyme must provide some other advantage. We observed that the [4Fe-4S] cluster of AcnB is in dynamic equilibrium with the surrounding iron pool, so that AcnB is rapidly demetallated when intracellular iron pools drop. AcnA and other dehydratases do not show this trait. Demetallated AcnB is known to bind its cognate mRNA. The absence of AcnB activity also causes the accumulation and excretion of citrate, an iron chelator for which E. coli synthesizes a transport system. Thus, AcnB may be retained as the primary aconitase because the lability of its exposed cluster allows E. coli to sense and respond to iron depletion. PMID:12486059

Mitochondrial Physiology in the Major Arbovirus Vector Aedes aegypti: Substrate Preferences and Sexual Differences Define Respiratory Capacity and Superoxide Production

PubMed Central

Soares, Juliana B. R. Correa; Gaviraghi, Alessandro; Oliveira, Marcus F.

2015-01-01

Adult females of Aedes aegypti are facultative blood sucking insects and vectors of Dengue and yellow fever viruses. Insect dispersal plays a central role in disease transmission and the extremely high energy demand posed by flight is accomplished by a very efficient oxidative phosphorylation process, which take place within flight muscle mitochondria. These organelles play a central role in energy metabolism, interconnecting nutrient oxidation to ATP synthesis, but also represent an important site of cellular superoxide production. Given the importance of mitochondria to cell physiology, and the potential contributions of this organelle for A. aegypti biology and vectorial capacity, here, we conducted a systematic assessment of mitochondrial physiology in flight muscle of young adult A. aegypti fed exclusively with sugar. This was carried out by determining the activities of mitochondrial enzymes, the substrate preferences to sustain respiration, the mitochondrial bioenergetic efficiency and capacity, in both mitochondria-enriched preparations and mechanically permeabilized flight muscle in both sexes. We also determined the substrates preferences to promote mitochondrial superoxide generation and the main sites where it is produced within this organelle. We observed that respiration in A. aegypti mitochondria was essentially driven by complex I and glycerol 3 phosphate dehydrogenase substrates, which promoted distinct mitochondrial bioenergetic capacities, but with preserved efficiencies. Respiration mediated by proline oxidation in female mitochondria was strikingly higher than in males. Mitochondrial superoxide production was essentially mediated through proline and glycerol 3 phosphate oxidation, which took place at sites other than complex I. Finally, differences in mitochondrial superoxide production among sexes were only observed in male oxidizing glycerol 3 phosphate, exhibiting higher rates than in female. Together, these data represent a significant step towards the understanding of fundamental mitochondrial processes in A. aegypti, with potential implications for its physiology and vectorial capacity. PMID:25803027

Superoxide produced by Kupffer cells is an essential effector in concanavalin A-induced hepatitis in mice.

PubMed

Nakashima, Hiroyuki; Kinoshita, Manabu; Nakashima, Masahiro; Habu, Yoshiko; Shono, Satoshi; Uchida, Takefumi; Shinomiya, Nariyoshi; Seki, Shuhji

2008-12-01

Although concanavalin A (Con-A)-induced experimental hepatitis is thought to be induced by activated T cells, natural killer T (NKT) cells, and cytokines, precise mechanisms are still unknown. In the current study, we investigated the roles of Kupffer cells, NKT cells, FasL, tumor necrosis factor (TNF), and superoxide in Con-A hepatitis in C57BL/6 mice. Removal of Kupffer cells using gadolinium chloride (GdCl(3)) from the liver completely inhibited Con-A hepatitis, whereas increased serum TNF and IFN-gamma levels were not inhibited at all. Unexpectedly, anti-FasL antibody pretreatment did not inhibit Con-A hepatitis, whereas it inhibited hepatic injury induced by a synthetic ligand of NKT cells, alpha-galactosylceramide. Furthermore, GdCl(3) pretreatment changed neither the activation-induced down-regulation of NK1.1 antigens as well as T cell receptors of NKT cells nor the increased expression of the CD69 activation antigen of hepatic T cells. CD68(+) Kupffer cells greatly increased in proportion in the early phase after Con-A injection; this increase was abrogated by GdCl(3) pretreatment. Anti-TNF antibody (Ab) pretreatment did not inhibit the increase of Kupffer cells, but it effectively suppressed superoxide/reactive oxygen production from Kupffer cells and the resulting hepatic injury. Conversely, depletion of NKT cells in mice by NK1.1 Ab pretreatment did suppress both the increase of CD68(+) Kupffer cells and Con-A hepatitis. Consistently, the diminution of oxygen radicals produced by Kupffer cells by use of free radical scavengers greatly inhibited Con-A hepatitis without suppressing cytokine production. However, adoptive transfer experiments also indicate that a close interaction/cooperation of Kupffer cells with NKT cells is essential for Con-A hepatitis. Superoxide produced by Kupffer cells may be the essential effector in Con-A hepatitis, and TNF and NKT cells support their activation and superoxide production.

The use of superoxide mixtures as air-revitalization chemicals in hyperbaric, self-contained, closed-circuit breathing apparatus

NASA Technical Reports Server (NTRS)

Wood, P. C.; Wydeven, T.

1985-01-01

In portable breathing apparatus applications at 1 atm, potassium superoxide (KO2) has exhibited low-utilization efficiency of the available oxygen (O2) and diminished carbon dioxide-(CO2) scrubbing capacity caused by the formation of a fused, hydrated-hydroxide/carbonate product coating on the superoxide granules. In earlier work, it was discovered that granules fabricated from an intimate mixture of KO2 and calcium superoxide, Ca(O2)2, did not exhibit formation of a fused product coating and the utilization efficiency with respect to both O2 release and CO2 absorption was superior to KO2 granules when both types of granules were reacted with humidified CO2 under identified conditions. In the work described here, single pellets of KO2, KO2/Ca(O2), mixtures and commercially available KO2 tables and granules were reacted with a flow of humidified CO2 in helium at 1- and 10-atm total pressure and at an initial temperature of 40 C. In the 1-atm flow tests, the reaction rates and utilization efficiency of the KO2/Ca(O2)2 pellets were markedly superior to the KO2 pellets, tablets, and granules when the samples were reacted under identical conditions. However, at 10 atm, the rates of O2 release and CO2 absorption, as well as the utilization efficiencies of all the superoxide samples, were one-third to one-eighth of the values observed at 1 atm. The decrease in reaction performance at 10 atm compared to that at 1 atm has been attributed principally to the lower bulk diffusivity of the CO2 and H2O reactants in helium at the higher pressure and secondarily to the moderation of the reaction temperature caused by the higher heat capacity of the 10-atm helium.

Neelaredoxin, an iron-binding protein from the syphilis spirochete, Treponema pallidum, is a superoxide reductase.

PubMed

Jovanović, T; Ascenso, C; Hazlett, K R; Sikkink, R; Krebs, C; Litwiller, R; Benson, L M; Moura, I; Moura, J J; Radolf, J D; Huynh, B H; Naylor, S; Rusnak, F

2000-09-15

Treponema pallidum, the causative agent of venereal syphilis, is a microaerophilic obligate pathogen of humans. As it disseminates hematogenously and invades a wide range of tissues, T. pallidum presumably must tolerate substantial oxidative stress. Analysis of the T. pallidum genome indicates that the syphilis spirochete lacks most of the iron-binding proteins present in many other bacterial pathogens, including the oxidative defense enzymes superoxide dismutase, catalase, and peroxidase, but does possess an orthologue (TP0823) for neelaredoxin, an enzyme of hyperthermophilic and sulfate-reducing anaerobes shown to possess superoxide reductase activity. To analyze the potential role of neelaredoxin in treponemal oxidative defense, we examined the biochemical, spectroscopic, and antioxidant properties of recombinant T. pallidum neelaredoxin. Neelaredoxin was shown to be expressed in T. pallidum by reverse transcriptase-polymerase chain reaction and Western blot analysis. Recombinant neelaredoxin is a 26-kDa alpha(2) homodimer containing, on average, 0.7 iron atoms/subunit. Mössbauer and EPR analysis of the purified protein indicates that the iron atom exists as a mononuclear center in a mixture of high spin ferrous and ferric oxidation states. The fully oxidized form, obtained by the addition of K(3)(Fe(CN)(6)), exhibits an optical spectrum with absorbances at 280, 320, and 656 nm; the last feature is responsible for the protein's blue color, which disappears upon ascorbate reduction. The fully oxidized protein has a A(280)/A(656) ratio of 10.3. Enzymatic studies revealed that T. pallidum neelaredoxin is able to catalyze a redox equilibrium between superoxide and hydrogen peroxide, a result consistent with it being a superoxide reductase. This finding, the first description of a T. pallidum iron-binding protein, indicates that the syphilis spirochete copes with oxidative stress via a primitive mechanism, which, thus far, has not been described in pathogenic bacteria.

Scoparone attenuates RANKL-induced osteoclastic differentiation through controlling reactive oxygen species production and scavenging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sang-Hyun; Jang, Hae-Dong, E-mail: haedong@hnu.kr

Scoparone, one of the bioactive components of Artemisia capillaris Thunb, has various biological properties including immunosuppressive, hepatoprotective, anti-allergic, anti-inflammatory, and antioxidant effects. This study aims at evaluating the anti-osteoporotic effect of scoparone and its underlying mechanism in vitro. Scoparone demonstrated potent cellular antioxidant capacity. It was also found that scoparone inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and suppressed cathepsin K and tartrate-resistant acid phosphatase (TRAP) expression via c-jun N-terminal kinase (JNK)/extracellular signal-regulated kinase (ERK)/p38-mediated c-Fos–nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling pathway. During osteoclast differentiation, the production of general reactive oxygen speciesmore » (ROS) and superoxide anions was dose-dependently attenuated by scoparone. In addition, scoparone diminished NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 1 (Nox1) expression and activation via the tumor necrosis factor receptor-associated factor 6 (TRAF6)–cSrc–phosphatidylinositol 3-kinase (PI3k) signaling pathway and prevented the disruption of mitochondrial electron transport chain system. Furthermore, scoparone augmented the expression of superoxide dismutase 1 (SOD1) and catalase (CAT). The overall results indicate that the inhibitory effect of scoparone on RANKL-induced osteoclast differentiation is attributed to the suppressive effect on ROS and superoxide anion production by inhibiting Nox1 expression and activation and protecting the mitochondrial electron transport chain system and the scavenging effect of ROS resulting from elevated SOD1 and CAT expression. - Highlights: • Scoparone dose-dependently inhibited RANKL-induced osteoclast differentiation. • Scoparone diminished general ROS and superoxide anions in a dose-dependent manner. • Scoparone inhibited Nox1 expression and activation. • Scoparone prevented the disruption of mitochondrial electron transport chain system. • Scoparone augmented superoxide dismutase and catalase expression.« less

Impressive Suppression of Colon Cancer Growth by Triple Combination SN38/EF24/Melatonin: "Oncogenic" Versus "Onco-Suppressive" Reactive Oxygen Species.

PubMed

Bakalova, Rumiana; Zhelev, Zhivko; Shibata, Sayaka; Nikolova, Biliana; Aoki, Ichio; Higashi, Tatsuya

2017-10-01

The study aimed to investigate the effect of multi-targeted combinations (SN38/EF24; SN38/EF24/melatonin) on the growth of colon cancer in experimental animals and their impact on the ratio "oncogenic"/"onco-suppressive" reactive oxygen species (ROS) - a crucial factor for triggering carcinogenesis, as well as for development of effective therapeutic strategies. The experiments were conducted on colon cancer-grafted mice - non-treated, SN38/EF24-treated and SN38/EF24/melatonin-treated within 22 days. The balance between different types of ROS was measured in vivo by nitroxide-enhanced magnetic resonance imaging (MRI), as well as on isolated tissue specimens by conventional analytical tests. Both combinations significantly suppressed the tumor growth. Impressive anticancer effect was observed in SN38/EF24/melatonin-treated mice - almost complete destruction of the tumor. Both types of ROS (superoxide and hydroperoxides) were elevated in cancer, but the MRI data suggest that the ratio between them tends towards superoxide. SN38/EF24 decreased the level of superoxide, but did not affect the level of hydroperoxides in the cancerous tissue, while SN38/EF24/melatonin decreased the level of superoxide below the control and increased significantly the level of hydroperoxides. The most important observations are that: (i) colon cancer was characterized by a vicious cycle, that ensures a permanent domination of "oncogenic" ROS (as superoxide) over "onco-suppressive" ROS (as hydrogen peroxide); (ii) the anticancer effect of the triple combination EF24/SN38/melatonin was accompanied by decreasing "oncogenic" and increasing "onco-suppressive" ROS; (iii) the ratio between both types of ROS could be a new onco-target for combined therapy; and (iv) nitroxide-enhanced MRI is a valuable tool for analyzing of this ratio. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Determination of an Effective Perfluorinated Compounds (PFCs) Oxidation Method

NASA Astrophysics Data System (ADS)

Siriwardena, D. P.; Crimi, M.; Holsen, T.; Bellona, C.

2014-12-01

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are a stable synthetic class of chemicals ubiquitously spread in environmental media (i.e. air, soil, biota, surface water and groundwater). The substances' strong polar carbon-fluorine bonds and their high thermal and chemical stability make them resistant to biological, chemical, and physical degradation. The purpose of this research is to identify the most effective oxidation method to treat perfluorinated compounds (PFCs) and their by-products that is suitable for in situ application. The laboratory oxidation study focuses on the more commonly detected and studied long-chain (C-8) PFAS; perfluorooctanoic acids (PFOA) and perfluorooctane sulfonic acid (PFOS). Existing research evaluating oxidizing treatment effectiveness on perfluoroalkyl sulfoinoic acids (PFSAs) is limited. A review of the literature and results from preliminary studies indicate that activated persulfate and catalyzed hydrogen peroxide propagation (CHP) reactions appear to be promising oxidants for PFOA. It has been demonstrated that the reactivity of superoxide in water increases in the presence of hydrogen peroxide (H2O2) and solids. Superoxide generated in CHP reactions degrades PFOA seemingly similar to superoxide-mediated destruction of the perhalogenated compounds.The goal of this study is to look at conditions that promote generation of superoxide and look at PFASs treatment effectiveness and byproduct generation. CHP reactions are conducted with varying amount of H2O2 and Fe(III) to determine the optimum conditions for PFC degradation. Results will be compared to those of another experiment using manganese dioxide as a CHP catalyst with varied H2O2 concentration to generate superoxide to degrade PFASs. Activated persulfate conditions to be compared include alkaline pH activation, heat activation, and dual oxidation (combined H2O2 and persulfate ). This presentation will focus on a comparison of oxidation effectiveness under the varied reaction conditions as well as on the oxidation intermediates and byproducts generated toward improved understanding of the potential for and limitations of in situ chemical oxidation (ISCO) for treatment of PFCs.

Loss of Melanin by Eye Retinal Pigment Epithelium Cells Is Associated with Its Oxidative Destruction in Melanolipofuscin Granules.

PubMed

Dontsov, A E; Sakina, N L; Ostrovsky, M A

2017-08-01

The effect of superoxide radicals on melanin destruction and degradation of melanosomes isolated from cells of retinal pigment epithelium (RPE) of the human eye was studied. We found that potassium superoxide causes destruction of melanin in melanosomes of human and bovine RPE, as well as destruction of melanin from the ink bag of squid, with the formation of fluorescent decay products having an emission maximum at 520-525 nm. The initial kinetics of the accumulation of the fluorescent decay products is linear. Superoxide radicals lead simultaneously to a decrease in the number of melanosomes and to a decrease in concentration of paramagnetic centers in them. Complete degradation of melanosomes leads to the formation of a transparent solution containing dissolved proteins and melanin degradation products that do not exhibit paramagnetic properties. To completely degrade one melanosome of human RPE, 650 ± 100 fmol of superoxide are sufficient. The concentration of paramagnetic centers in a melanolipofuscin granule of human RPE is on average 32.5 ± 10.4% (p < 0.05, 150 eyes) lower than in a melanosome, which indicates melanin undergoing a destruction process in these granules. RPE cells also contain intermediate granules that have an EPR signal with a lower intensity than that of melanolipofuscin granules, but higher than that of lipofuscin granules. This signal is due to the presence of residual melanin in these granules. Irradiation of a mixture of melanosomes with lipofuscin granules with blue light (450 nm), in contrast to irradiation of only melanosomes, results in the appearance of fluorescent melanin degradation products. We suggest that one of the main mechanisms of age-related decrease in melanin concentration in human RPE cells is its destruction in melanolipofuscin granules under the action of superoxide radicals formed during photoinduced oxygen reduction by lipofuscin fluorophores.

Effects of pyrogallol, hydroquinone and duroquinone on responses to nitrergic nerve stimulation and NO in the rat anococcygeus muscle

PubMed Central

La, Mylinh; Rand, Michael J

1999-01-01

The hypothesis that endogenous superoxide dismutase (SOD) protects the nitrergic transmitter from inactivation by superoxide and that this explains the lack of sensitivity of the transmitter to superoxide generators was tested in the rat isolated anococcygeus muscle.Responses to nitrergic nerve stimulation or to NO were not significantly affected by exogenous SOD or by the Cu/Zn SOD inhibitor diethyldithiocarbamic acid (DETCA).Hydroquinone produced a concentration-dependent reduction of responses to NO with an IC50 of 27 μM, and higher concentrations reduced relaxant responses to nitrergic nerve stimulation with an IC50 of 612 μM. The effects of hydroquinone were only slightly reversed by SOD, so it does not appear to be acting as a superoxide generator.Pyrogallol produced a concentration-dependent reduction in responses to NO with an IC50 value of 39 μM and this effect was reversed by SOD (100–1000 u ml−1). Pyrogallol did not affect responses to nitrergic nerve stimulation. Treatment with DETCA did not alter the differentiating action of pyrogallol.Duroquinone produced a concentration-dependent reduction of relaxations to NO with an IC50 value of 240 μM and 100 μM slightly decreased nitrergic relaxations. After treatment with DETCA, duroquinone produced greater reductions of relaxant responses to NO and to nitrergic stimulation, the IC50 values being 8.5 μM for NO and 40 μM for nitrergic nerve stimulation: these reductions were reversed by SOD.The findings do not support the hypothesis that the presence of Cu/Zn SOD explains the greater susceptibility of NO than the nitrergic transmitter to the superoxide generator pyrogallol, but suggest that it may play a role in the effects of duroquinone. PMID:10051154

Ghrelin-Related Peptides Exert Protective Effects in the Cerebral Circulation of Male Mice Through a Nonclassical Ghrelin Receptor(s)

PubMed Central

Ku, Jacqueline M.; Andrews, Zane B.; Barsby, Tom; Reichenbach, Alex; Lemus, Moyra B.; Drummond, Grant R.; Sleeman, Mark W.; Spencer, Sarah J.; Sobey, Christopher G.

2015-01-01

The ghrelin-related peptides, acylated ghrelin, des-acylated ghrelin, and obestatin, are novel gastrointestinal hormones. We firstly investigated whether the ghrelin gene, ghrelin O-acyltransferase, and the ghrelin receptor (GH secretagogue receptor 1a [GHSR1a]) are expressed in mouse cerebral arteries. Secondly, we assessed the cerebrovascular actions of ghrelin-related peptides by examining their effects on vasodilator nitric oxide (NO) and superoxide production. Using RT-PCR, we found the ghrelin gene and ghrelin O-acyltransferase to be expressed at negligible levels in cerebral arteries from male wild-type mice. mRNA expression of GHSR1a was also found to be low in cerebral arteries, and GHSR protein was undetectable in GHSR-enhanced green fluorescent protein mice. We next found that exogenous acylated ghrelin had no effect on the tone of perfused cerebral arteries or superoxide production. By contrast, exogenous des-acylated ghrelin or obestatin elicited powerful vasodilator responses (EC50 < 10 pmol/L) that were abolished by the NO synthase inhibitor Nω-nitro-L-arginine methyl ester. Furthermore, exogenous des-acylated ghrelin suppressed superoxide production in cerebral arteries. Consistent with our GHSR expression data, vasodilator effects of des-acylated ghrelin or obestatin were sustained in the presence of YIL-781 (GHSR1a antagonist) and in arteries from Ghsr-deficient mice. Using ghrelin-deficient (Ghrl−/−) mice, we also found that endogenous production of ghrelin-related peptides regulates NO bioactivity and superoxide levels in the cerebral circulation. Specifically, we show that NO bioactivity was markedly reduced in Ghrl−/− vs wild-type mice, and superoxide levels were elevated. These findings reveal protective actions of exogenous and endogenous ghrelin-related peptides in the cerebral circulation and show the existence of a novel ghrelin receptor(s) in the cerebral endothelium. PMID:25322462

Mitochondrial Based Treatments that Prevent Post-Traumatic Osteoarthritis in a Translational Large Animal Intraarticular Fracture Survival Model

DTIC Science & Technology

2013-09-01

included an oxidant scavenger, (N- Acetylcysteine ), a drug that reduces mitochondrial superoxide production by blocking electron flow through complex I...selection of compounds included an oxidant scavenger, (N- Acetylcysteine ), a drug that reduces mitochondrial superoxide production by blocking...2mM N- acetylcysteine 5 3. 5mM NAC 5 4. 20mM NAC 5 5. 20µM Cytochalasin B 5 6. 10µM Nocodazole 4 7. 2.5mM Amobarbital 5 Table. Dose

Hypolipidemic and antioxidant activity of mountain celery (Cryptotaenia japonica Hassk) seed essential oils.

PubMed

Cheng, Ming-Ching; Lin, Li-Yun; Yu, Tung-Hsi; Peng, Robert Y

2008-06-11

Mountain celery seed essential oils (MC-E) contained 109 compounds, including mainly nine kinds of monoterpenoids, 31 kinds of of sesquiterpenoids, and 22 kinds of alcohols. A successive gel column adsorption with solvent fractionation yielded four fractionates. The pentane fractionate revealed potent hypolipidemic but poor antioxidant activities. The ether fractionate exhibited strong hypolipidemic activity in addition to excellent 1,1-diphenyl-2-picrylhydrazyl free radical- and superoxide anion-scavenging capabilities. The third acetone fractionate only showed moderate superoxide anion-scavenging activity. Finally, the fourth methanol fractionate having a rather high content of gamma-selinene, 2-methylpropanal, and Z-9-octadecenamide uniquely revealed very strong superoxide anion-scavenging capability. All MC diets except the MC-E-added diet simultaneously exhibited both significant hypolipidemic and high-density lipoprotein-cholesterol (HDL-C)-elevating capabilities. However, all diets totally failed to affect the hepatic phospholipid levels. Conclusively, the MC-E can be fractionated by such a separation technology to produce products uniquely possessing hypolipidemic and HDL-C-elevating activities.

Group IIA secretory phospholipase A2 (GIIA) mediates apoptotic death during NMDA receptor activation in rat primary cortical neurons.

PubMed

Chiricozzi, Elena; Fernandez-Fernandez, Seila; Nardicchi, Vincenza; Almeida, Angeles; Bolaños, Juan Pedro; Goracci, Gianfrancesco

2010-03-01

Phospholipases A(2) (PLA(2)) participate in neuronal death signalling pathways because of their ability to release lipid mediators, although the contribution of each isoform and mechanism of neurotoxicity are still elusive. Using a novel fluorogenic method to assess changes in a PLA(2) activity by flow cytometry, here we show that the group IIA secretory phospholipase A(2) isoform (GIIA) was specifically activated in cortical neurons following stimulation of N-methyl-d-aspartate glutamate receptor subtype (NMDAR). For activation, GIIA required Ca(2+) and reactive oxygen/nitrogen species, and inhibition of its activity fully prevented NMDAR-mediated neuronal apoptotic death. Superoxide, nitric oxide or peroxynitrite donors stimulated GIIA activity, which mediated neuronal death. Intriguingly, we also found that GIIA activity induced mitochondrial superoxide production after NMDAR stimulation. These results reveal a novel role for GIIA in excitotoxicity both as target and producer of superoxide in a positive-loop of activation that may contribute to the propagation of neurodegeneration.

Evaluation of the Destruction of the Harmful Cyanobacteria, Microcystis aeruginosa, with a Cavitation and Superoxide Generating Water Treatment Reactor.

PubMed

Medina, Victor F; Griggs, Chris S; Thomas, Catherine

2016-06-01

Cyanobacterial/Harmful Algal Blooms are a major issue for lakes and reservoirs throughout the U.S.A. An effective destructive technology could be useful to protect sensitive areas, such as areas near water intakes. The study presented in this article explored the use of a reactor called the KRIA Water Treatment System. The reactor focuses on the injection of superoxide (O2 (-)), which is generated electrochemically from the atmosphere, into the water body. In addition, the injection process generates a significant amount of cavitation. The treatment process was tested in 190-L reactors spiked with water from cyanobacterial contaminated lakes. The treatment was very effective at destroying the predominant species of cyanobacteria, Microcystis aeruginosa, organic matter, and decreasing chlorophyll concentration. Microcystin toxin concentrations were also reduced. Data suggest that cavitation alone was an effective treatment, but the addition of superoxide improved performance, particularly regarding removal of cyanobacteria and reduction of microcystin concentration.

Detection of different Leishmania spp. and Trypanosoma cruzi antibodies in cats from the Yucatan Peninsula (Mexico) using an iron superoxide dismutase excreted as antigen.

PubMed

Longoni, Silvia S; López-Cespedes, Angeles; Sánchez-Moreno, Manuel; Bolio-Gonzalez, Manuel E; Sauri-Arceo, Carlos H; Rodríguez-Vivas, Roger I; Marín, Clotilde

2012-09-01

Although human leishmaniasis has been reported in 20 states in Mexico, no case of leishmaniasis has been reported in cats to date. In the Yucatan Peninsula, it has been found that dogs may act as reservoirs for at least three Leishmania species (Leishmania mexicana, Leishmania braziliensis, and Leishmania panamensis). In this study we identified specific antibodies against these three Leishmania spp. and Trypanosoma cruzi in the sera from 95 cats from two States on the Yucatan Peninsula, namely Quintana Roo and Yucatan, by ELISA and Western blot techniques using whole extract and an iron superoxide dismutase excreted by the parasites as antigens. As well as demonstrating the presence of trypanosomatid antibodies in the feline population on the Yucatan Peninsula, we were also able to confirm the high sensitivity and specificity of the iron superoxide dismutase antigen secreted by them, which may prove to be very useful in epidemiological studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhancing and inhibiting effects of aromatic compounds on luminol-dimethylsulfoxide-OH(-) chemiluminescence and determination of intermediates in oxidative hair dyes by HPLC with chemiluminescence detection.

PubMed

Zhou, Jian; Xu, Hong; Wan, Guo-Hui; Duan, Chun-Feng; Cui, Hua

2004-10-08

The effect of 36 aromatic compounds on the luminol-dimethylsulfoxide-OH(-) chemiluminescence (CL) was systematically studied. It was found that dihydroxybenzenes, and ortho- and para-substituted aminophenols and phenylenediamines inhibited the CL and phenols with three or more than three hydroxyls except phloroglucin tended to enhance the CL. The CL inhibition and enhancement was proposed to be dependent on whether superoxide anion radical (O(2)(-)) was competitively consumed by compounds in the CL system. Trihydroxybenzenes were capable of generating superoxide anion radical, leading to the CL enhancement, whereas dihydroxybenzenes were superoxide anion radical scavenger, causing the CL inhibition. Based on the inhibited CL, a novel method for the simultaneous determination of p-phenylenediamine, o-phenylenediamine, p-aminophenol, o-aminophenol, resorcinol and hydroquinone by high-performance liquid chromatography coupled with chemiluminescence detection was developed. The method has been successfully applied to determine intermediates in oxidative hair dyes and wastewater of shampooing after hair dyed.

Use of spin traps to detect superoxide production in living cells by electron paramagnetic resonance (EPR) spectroscopy.

PubMed

Abbas, Kahina; Babić, Nikola; Peyrot, Fabienne

2016-10-15

Detection of superoxide produced by living cells has been an on-going challenge in biology for over forty years. Various methods have been proposed to address this issue, among which spin trapping with cyclic nitrones coupled to EPR spectroscopy, the gold standard for detection of radicals. This technique is based on the nucleophilic addition of superoxide to a diamagnetic cyclic nitrone, referred to as the spin trap, and the formation of a spin adduct, i.e. a persistent radical with a characteristic EPR spectrum. The first application of spin trapping to living cells dates back 1979. Since then, considerable improvements of the method have been achieved both in the structures of the spin traps, the EPR methodology, and the design of the experiments including appropriate controls. Here, we will concentrate on technical aspects of the spin trapping/EPR technique, delineating recent breakthroughs, inherent limitations, and potential artifacts. Copyright © 2016 Elsevier Inc. All rights reserved.

DNA damage during glycation of lysine by methylglyoxal: assessment of vitamins in preventing damage.

PubMed

Suji, G; Sivakami, S

2007-11-01

Amino acids react with methylglyoxal to form advanced glycation end products. This reaction is known to produce free radicals. In this study, cleavage to plasmid DNA was induced by the glycation of lysine with methylglyoxal in the presence of iron(III). This system was found to produce superoxide as well as hydroxyl radicals. The abilities of various vitamins to prevent damage to plasmid DNA were evaluated. Pyridoxal-5-phosphate showed maximum protection, while pyridoxamine showed no protection. The protective abilities could be directly correlated to inhibition of production of hydroxyl and superoxide radicals. Pyridoxal-5-phosphate exhibited low radical scavenging ability as evaluated by its TEAC, but showed maximum protection probably by interfering in free radical production. Pyridoxamine did not inhibit free radical production. Thiamine and thiamine pyrophosphate, both showed protective effects albeit to different extents. Tetrahydrofolic acid showed better antioxidant activity than folic acid but was found to damage DNA by itself probably by superoxide generation.

Recent trends in electrochemical biosensors of superoxide dismutases.

PubMed

Balamurugan, Murugesan; Santharaman, Paulraj; Madasamy, Thangamuthu; Rajesh, Seenivasan; Sethy, Niroj Kumar; Bhargava, Kalpana; Kotamraju, Srigiridhar; Karunakaran, Chandran

2018-09-30

Superoxide dismutases (SODs), a family of ubiquitous enzymes, provide essential protection to biological systems against uncontrolled reactions with oxygen- and nitrogen- based radical species. We review first the role of SODs in oxidative stress and the other biological functions such as peroxidase, nitrite oxidase, thiol oxidase activities etc., implicating its role in neurodegenerative, cardiovascular diseases, and ageing. Also, this review focuses on the development of electrochemical label-free immunosensor for SOD1 and the recent advances in biosensing assay methods based on their catalytic and biological functions with various substrates including reactive oxygen species (superoxide anion radical, hydrogen peroxide), nitric oxide metabolites (nitrite, nitrate) and thiols using thiol oxidase activity. Furthermore, we emphasize the progress made in improving the detection performance through incorporation of the SOD into conducting polymers and nanocomposite matrices. In addition, we address the potential opportunities, challenges, advances in electrochemical-sensing platforms and development of portable analyzer for point-of-care applications. Copyright © 2018 Elsevier B.V. All rights reserved.

Dissolution and ionization of sodium superoxide in sodium–oxygen batteries

PubMed Central

Kim, Jinsoo; Park, Hyeokjun; Lee, Byungju; Seong, Won Mo; Lim, Hee-Dae; Bae, Youngjoon; Kim, Haegyeom; Kim, Won Keun; Ryu, Kyoung Han; Kang, Kisuk

2016-01-01

With the demand for high-energy-storage devices, the rechargeable metal–oxygen battery has attracted attention recently. Sodium–oxygen batteries have been regarded as the most promising candidates because of their lower-charge overpotential compared with that of lithium–oxygen system. However, conflicting observations with different discharge products have inhibited the understanding of precise reactions in the battery. Here we demonstrate that the competition between the electrochemical and chemical reactions in sodium–oxygen batteries leads to the dissolution and ionization of sodium superoxide, liberating superoxide anion and triggering the formation of sodium peroxide dihydrate (Na2O2·2H2O). On the formation of Na2O2·2H2O, the charge overpotential of sodium–oxygen cells significantly increases. This verification addresses the origin of conflicting discharge products and overpotentials observed in sodium–oxygen systems. Our proposed model provides guidelines to help direct the reactions in sodium–oxygen batteries to achieve high efficiency and rechargeability. PMID:26892931

Oxidant and enzymatic antioxidant status (gene expression and activity) in the brain of chickens with cold-induced pulmonary hypertension

NASA Astrophysics Data System (ADS)

Hassanpour, Hossein; Khalaji-Pirbalouty, Valiallah; Nasiri, Leila; Mohebbi, Abdonnaser; Bahadoran, Shahab

2015-11-01

To evaluate oxidant and antioxidant status of the brain (hindbrain, midbrain, and forebrain) in chickens with cold-induced pulmonary hypertension, the measurements of lipid peroxidation, protein oxidation, antioxidant capacity, enzymatic activity, and gene expression (for catalase, glutathione peroxidase, and superoxide dismutases) were done. There were high lipid peroxidation/protein oxidation and low antioxidant capacity in the hindbrain of cold-induced pulmonary hypertensive chickens compared to control ( P < 0.05). In the hypertensive chickens, superoxide dismutase activity was decreased (forebrain, midbrain, and hindbrain), while catalase activity was increased (forebrain and midbrain) ( P < 0.05). Glutathione peroxidase activity did not change. Relative gene expression of catalase and superoxide dismutases (1 and 2) was downregulated, while glutathione peroxidase was upregulated in the brain of the cold-induced pulmonary hypertensive chickens. Probably, these situations in the oxidant and antioxidant status of the brain especially hindbrain may change its function at cardiovascular center and sympathetic nervous system to exacerbate pulmonary hypertension.

siRNA-based Analysis of the Abrogation of the Protective Function of Membrane-associated Catalase of Tumor Cells.

PubMed

Bauer, Georg

2017-02-01

Tumor cells, in contrast to non-malignant cells, show sustained expression of membrane-associated NADPH oxidase-1 and therefore generate extracellular superoxide anions and their dismutation product H 2 O 2 In order to prevent intercellular reactive oxygen species/reactive nitrogen species (ROS/RNS)-dependent apoptosis-inducing signaling, tumor cells need to express membrane-associated catalase that interferes with HOCl and nitric oxide/peroxynitrite signaling. Catalase is attached to tumor cells through the activity of transglutaminase-2 and is prevented from superoxide anion-dependent inhibition through coexpression of membrane-associated superoxide dismutase. Therefore, specific inhibition of membrane-associated catalase should reactivate intercellular ROS/RNS-dependent apoptosis-inducing signaling. These processes are analyzed here through small interfering RNA-mediated knockdown of essential signaling compounds. This allows to establish a rather comprehensive picture of intercellular ROS/RNS signaling that may be instrumental for future therapeutic approaches. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Superoxide Anion Radical Production in the Tardigrade Paramacrobiotus richtersi, the First Electron Paramagnetic Resonance Spin-Trapping Study.

PubMed

Savic, Aleksandar G; Guidetti, Roberto; Turi, Ana; Pavicevic, Aleksandra; Giovannini, Ilaria; Rebecchi, Lorena; Mojovic, Milos

2015-01-01

Anhydrobiosis is an adaptive strategy that allows withstanding almost complete body water loss. It has been developed independently by many organisms belonging to different evolutionary lines, including tardigrades. The loss of water during anhydrobiotic processes leads to oxidative stress. To date, the metabolism of free radicals in tardigrades remained unclear. We present a method for in vivo monitoring of free radical production in tardigrades, based on electron paramagnetic resonance and spin-trap DEPMPO, which provides simultaneous identification of various spin adducts (i.e., different types of free radicals). The spin trap can be easily absorbed in animals, and tardigrades stay alive during the measurements and during 24-h monitoring after the treatment. The results show that hydrated specimens of the tardigrade Paramacrobiotus richtersi produce the pure superoxide anion radical ((•)O2(-)). This is an unexpected result, as all previously examined animals and plants produce both superoxide anion radical and hydroxyl radical ((•)OH) or exclusively hydroxyl radical.

Regulation of NADH/CoQ oxidoreductase: do phosphorylation events affect activity?

PubMed

Maj, Mary C; Raha, Sandeep; Myint, Tomoko; Robinson, Brian H

2004-01-01

We had previously suggested that phosphorylation of proteins by mitochondrial kinases regulate the activity of NADH/CoQ oxidoreductase. Initial data showed that pyruvate dehydrogenase kinase (PDK) and cAMP-dependent protein kinase A (PKA) phosphorylate mitochondrial membrane proteins. Upon phosphorylation with crude PDK, mitochondria appeared to be deficient in NADH/cytochrome c reductase activity associated with increased superoxide production. Conversely, phosphorylation by PKA resulted in increased NADH/cytochrome c reductase activity and decreased superoxide formation. Current data confirms PKA involvement in regulating Complex I activity through phosphorylation of an 18 kDa subunit. Beef heart NADH/ cytochrome c reductase activity increases to 150% of control upon incubation with PKA and ATP-gamma-S. We have cloned the four human isoforms of PDK and purified beef heart Complex I. Incubation of mitochondria with PDK isoforms and ATP did not alter Complex I activity or superoxide production. Radiolabeling of mitochondria and purified Complex I with PDK failed to reveal phosphorylated proteins.

Dissolution and ionization of sodium superoxide in sodium-oxygen batteries.

PubMed

Kim, Jinsoo; Park, Hyeokjun; Lee, Byungju; Seong, Won Mo; Lim, Hee-Dae; Bae, Youngjoon; Kim, Haegyeom; Kim, Won Keun; Ryu, Kyoung Han; Kang, Kisuk

2016-02-19

With the demand for high-energy-storage devices, the rechargeable metal-oxygen battery has attracted attention recently. Sodium-oxygen batteries have been regarded as the most promising candidates because of their lower-charge overpotential compared with that of lithium-oxygen system. However, conflicting observations with different discharge products have inhibited the understanding of precise reactions in the battery. Here we demonstrate that the competition between the electrochemical and chemical reactions in sodium-oxygen batteries leads to the dissolution and ionization of sodium superoxide, liberating superoxide anion and triggering the formation of sodium peroxide dihydrate (Na2O2·2H2O). On the formation of Na2O2·2H2O, the charge overpotential of sodium-oxygen cells significantly increases. This verification addresses the origin of conflicting discharge products and overpotentials observed in sodium-oxygen systems. Our proposed model provides guidelines to help direct the reactions in sodium-oxygen batteries to achieve high efficiency and rechargeability.

Antioxidants and biomarkers of oxidative damage in the saliva of patients with Down's syndrome.

PubMed

de Sousa, Michelle Cardoso; Vieira, Rafael Brizola; Dos Santos, Danielle Sá; Carvalho, Claudio Antonio Talge; Camargo, Samira Esteves Afonso; Mancini, Maria Nadir Gasparoto; de Oliveira, Luciane Dias

2015-04-01

The aim of this study was to investigate enzymatic and non-enzymatic antioxidant systems and levels of biomarker levels of oxidative damage in the saliva of patients with Down's syndrome (DS). Saliva samples were collected from 30 patients with DS and control group (age: 14-24 years). Subsequently, the concentrations of superoxide dismutase, concentration of malondialdehyde, carbonylated proteins, uric acid, vitamin C and total protein, peroxidase activity and total antioxidant capacity were analyzed. Patients with DS presented significantly higher concentrations of superoxide dismutase, higher levels of malondialdehyde and salivary total protein content than controls (p<0.05). Conversely, no difference in carbonylated proteins or antioxidants (uric acid, vitamin C, peroxidase, and total antioxidant capacity) was observed between DS patients and controls (p>0.05). Patients with DS are more vulnerable to oxidative stress in saliva as indicated by the significant increase in malondialdehyde and superoxide dismutase concentrations found in this study. Copyright © 2014 Elsevier Ltd. All rights reserved.

Characterization of fish Cu/Zn-superoxide dismutase and its protection from oxidative stress.

PubMed

Ken, Chuian-Fu; Lin, Chi-Tsai; Shaw, Jei-Fu; Wu, Jen-Leih

2003-01-01

Copper/zinc superoxide dismutase was cloned from the zebrafish ( Danio rerio). The full coding region of the zebrafish superoxide dismutase (ZSOD) complementary DNA was ligated with pET-20b(+) and successfully expressed in Escherichia coli strain AD494(DE3)pLysS. The active enzyme was purified by His tagging. The ZSOD yield was 6 mg from 0.2 L of E. coli culture, and the specific activity was 2000 U/mg as assayed using a RANSOD kit. The enzyme stability was characterized by reaction to temperature, pH, and detergent treatment. The results showed enzyme activity was still active after heat treatment at 70 degrees C for 10 minutes, resistant to pH treatment from 2.3 to 12, and resistant to treatment with sodium dodecyl sulfate (SDS) under 4%. In addition, the recombinant ZSOD was used to protect fish from 100 ppm of paraquat-induced oxidative injury by soaking fish larva in 55 micro g/ml SOD enzyme. The results were significant.

Copper-zinc superoxide dismutase is activated through a sulfenic acid intermediate at a copper ion entry site.

PubMed

Fetherolf, Morgan M; Boyd, Stefanie D; Taylor, Alexander B; Kim, Hee Jong; Wohlschlegel, James A; Blackburn, Ninian J; Hart, P John; Winge, Dennis R; Winkler, Duane D

2017-07-21

Metallochaperones are a diverse family of trafficking molecules that provide metal ions to protein targets for use as cofactors. The copper chaperone for superoxide dismutase (Ccs1) activates immature copper-zinc superoxide dismutase (Sod1) by delivering copper and facilitating the oxidation of the Sod1 intramolecular disulfide bond. Here, we present structural, spectroscopic, and cell-based data supporting a novel copper-induced mechanism for Sod1 activation. Ccs1 binding exposes an electropositive cavity and proposed "entry site" for copper ion delivery on immature Sod1. Copper-mediated sulfenylation leads to a sulfenic acid intermediate that eventually resolves to form the Sod1 disulfide bond with concomitant release of copper into the Sod1 active site. Sod1 is the predominant disulfide bond-requiring enzyme in the cytoplasm, and this copper-induced mechanism of disulfide bond formation obviates the need for a thiol/disulfide oxidoreductase in that compartment. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Endothelinergic Contractile Hyperreactivity in Rat Contralateral Carotid to Balloon Injury: Integrated Role for ETB Receptors and Superoxide Anion

PubMed Central

Gimenes, Lilian R.; Gomes, Mayara S.; do Vale, Bruno N.; Cardoso, Cristina R. B.; de Oliveira, Ana M.; Moreira, Josimar D.

2017-01-01

Temporal consequences of neurocompensation to balloon injury on endothelinergic functionality in rat contralateral carotid were evaluated. Rats underwent balloon injury in left carotid and were treated with CP-96345 (NK1 antagonist). Concentration-response curves for endothelin-1 were obtained in contralateral (right) carotid at 2, 8, 16, 30, or 45 days after surgery in the absence or presence of BQ-123 (ETA antagonist), BQ-788 (ETB antagonist), or Tempol (superoxide-dismutase mimic). Endothelin-1-induced calcium mobilization was evaluated in functional assays carried out with BQ-123, BQ-788, or Tempol. Endothelin-1-induced NADPH oxidase-driven superoxide generation was measured by lucigenin chemiluminescence assays performed with BQ-123 or BQ-788. Endothelin-1-induced contraction was increased in contralateral carotid from the sixteenth day after surgery. This response was restored in CP-96345-treated rats. Endothelium removal or BQ-123 did not change endothelin-1-induced contraction in contralateral carotid. This response was restored by BQ-788 or Tempol. Contralateral carotid exhibited an increased endothelin-1-induced calcium mobilization, which was restored by BQ-788 or Tempol. Contralateral carotid exhibited an increased endothelin-1-induced lucigenin chemiluminescence, which was restored by BQ-788. We conclude that the NK1-mediated neurocompensatory response to balloon injury elicits a contractile hyperreactivity to endothelin-1 in rat contralateral carotid by enhancing the muscular ETB-mediated NADPH oxidase-driven generation of superoxide, which activates calcium channels. PMID:29062837

Eukaryotic copper-only superoxide dismutases (SODs): A new class of SOD enzymes and SOD-like protein domains.

PubMed

Robinett, Natalie G; Peterson, Ryan L; Culotta, Valeria C

2018-03-30

The copper-containing superoxide dismutases (SODs) represent a large family of enzymes that participate in the metabolism of reactive oxygen species by disproportionating superoxide anion radical to oxygen and hydrogen peroxide. Catalysis is driven by the redox-active copper ion, and in most cases, SODs also harbor a zinc at the active site that enhances copper catalysis and stabilizes the protein. Such bimetallic Cu,Zn-SODs are widespread, from the periplasm of bacteria to virtually every organelle in the human cell. However, a new class of copper-containing SODs has recently emerged that function without zinc. These copper-only enzymes serve as extracellular SODs in specific bacteria ( i.e. Mycobacteria), throughout the fungal kingdom, and in the fungus-like oomycetes. The eukaryotic copper-only SODs are particularly unique in that they lack an electrostatic loop for substrate guidance and have an unusual open-access copper site, yet they can still react with superoxide at rates limited only by diffusion. Copper-only SOD sequences similar to those seen in fungi and oomycetes are also found in the animal kingdom, but rather than single-domain enzymes, they appear as tandem repeats in large polypeptides we refer to as CSRPs (copper-only SOD-repeat proteins). Here, we compare and contrast the Cu,Zn versus copper-only SODs and discuss the evolution of copper-only SOD protein domains in animals and fungi. © 2018 by The American Society for Biochemistry and Molecular Biology, Inc.

Differential expression of copper-zinc superoxide dismutase gene of Polygonum sibiricum leaves, stems and underground stems, subjected to high-salt stress.

PubMed

Qu, Chun-Pu; Xu, Zhi-Ru; Liu, Guan-Jun; Liu, Chun; Li, Yang; Wei, Zhi-Gang; Liu, Gui-Feng

2010-01-01

In aerobic organisms, protection against oxidative damage involves the combined action of highly specialized antioxidant enzymes, such as copper-zinc superoxide dismutase. In this work, a cDNA clone which encodes a copper-zinc superoxide dismutase gene, named PS-CuZnSOD, has been identified from P. sibiricum Laxm. by the rapid amplification of cDNA ends method (RACE). Analysis of the nucleotide sequence reveals that the PS-CuZnSOD gene cDNA clone consists of 669 bp, containing 87 bp in the 5' untranslated region; 459 bp in the open reading frame (ORF) encoding 152 amino acids; and 123 bp in 3' untranslated region. The gene accession nucleotide sequence number in GenBank is GQ472846. Sequence analysis indicates that the protein, like most plant superoxide dismutases (SOD), includes two conserved ecCuZnSOD signatures that are from the amino acids 43 to 51, and from the amino acids 137 to 148, and it has a signal peptide extension in the front of the N-terminus (1-16 aa). Expression analysis by real-time quantitative PCR reveals that the PS-CuZnSOD gene is expressed in leaves, stems and underground stems. PS-CuZnSOD gene expression can be induced by 3% NaHCO(3). The different mRNA levels' expression of PS-CuZnSOD show the gene's different expression modes in leaves, stems and underground stems under the salinity-alkalinity stress.

Mitogen-activated protein kinase kinase 5 (MKK5)-mediated signalling cascade regulates expression of iron superoxide dismutase gene in Arabidopsis under salinity stress

PubMed Central

Xing, Yu; Chen, Wei-hua; Jia, Wensuo; Zhang, Jianhua

2015-01-01

Superoxide dismutases (SODs) are involved in plant adaptive responses to biotic and abiotic stresses but the upstream signalling process that modulates their expression is not clear. Expression of two iron SODs, FSD2 and FSD3, was significantly increased in Arabidopsis in response to NaCl treatment but blocked in transgenic MKK5-RNAi plant, mkk5. Using an assay system for transient expression in protoplasts, it was found that mitogen-activated protein kinase kinase 5 (MKK5) was also activated in response to salt stress. Overexpression of MKK5 in wild-type plants enhanced their tolerance to salt treatments, while mkk5 mutant exhibited hypersensitivity to salt stress in germination on salt-containing media. Moreover, another kinase, MPK6, was also involved in the MKK5-mediated iron superoxide dismutase (FSD) signalling pathway in salt stress. The kinase activity of MPK6 was totally turned off in mkk5, whereas the activity of MPK3 was only partially blocked. MKK5 interacted with the MEKK1 protein that was also involved in the salt-induced FSD signalling pathway. These data suggest that salt-induced FSD2 and FSD3 expressions are influenced by MEKK1 via MKK5–MPK6-coupled signalling. This MAP kinase cascade (MEKK1, MKK5, and MPK6) mediates the salt-induced expression of iron superoxide dismutases. PMID:26136265

Superoxide and Singlet Oxygen Produced within the Thylakoid Membranes Both Cause Photosystem I Photoinhibition.

PubMed

Takagi, Daisuke; Takumi, Shigeo; Hashiguchi, Masaki; Sejima, Takehiro; Miyake, Chikahiro

2016-07-01

Photosystem I (PSI) photoinhibition suppresses plant photosynthesis and growth. However, the mechanism underlying PSI photoinhibition has not been fully clarified. In this study, in order to investigate the mechanism of PSI photoinhibition in higher plants, we applied repetitive short-pulse (rSP) illumination, which causes PSI-specific photoinhibition in chloroplasts isolated from spinach leaves. We found that rSP treatment caused PSI photoinhibition, but not PSII photoinhibition in isolated chloroplasts in the presence of O2 However, chloroplastic superoxide dismutase and ascorbate peroxidase activities failed to protect PSI from its photoinhibition. Importantly, PSI photoinhibition was largely alleviated in the presence of methyl viologen, which stimulates the production of reactive oxygen species (ROS) at the stromal region by accepting electrons from PSI, even under the conditions where CuZn-superoxide dismutase and ascorbate peroxidase activities were inactivated by KCN. These results suggest that the ROS production site, but not the ROS production rate, is critical for PSI photoinhibition. Furthermore, we found that not only superoxide (O2 (-)) but also singlet oxygen ((1)O2) is involved in PSI photoinhibition induced by rSP treatment. From these results, we suggest that PSI photoinhibition is caused by both O2 (-) and (1)O2 produced within the thylakoid membranes when electron carriers in PSI become highly reduced. Here, we show, to our knowledge, new insight into the PSI photoinhibition in higher plants. © 2016 American Society of Plant Biologists. All Rights Reserved.

Electrode Reactions Coupled with Chemical Reactions of Oxygen, Water and Acetaldehyde in an Ionic Liquid: New Approaches for Sensing Volatile Organic Compounds.

PubMed

Chi, Xiaowei; Tang, Yongan; Zeng, Xiangqun

2016-10-20

Water and oxygen are ubiquitous present in ambient conditions. This work studies the unique oxygen, trace water and a volatile organic compound (VOC) acetaldehyde redox chemistry in a hydrophobic and aprotic ionic liquid (IL), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Bmpy] [NTf 2 ]) by cyclic voltammetry and potential step methods. One electron oxygen reduction leads to superoxide radical formation in the IL. Trace water in the IL acts as a protic species that reacts with the superoxide radical. Acetaldehyde is a stronger protic species than water for reacting with the superoxide radical. The presence of trace water in the IL was also demonstrated to facilitate the electro-oxidation of acetaldehyde, with similar mechanism to that in the aqueous solutions. A multiple-step coupling reaction mechanism between water, superoxide radical and acetaldehyde has been described. The unique characteristics of redox chemistry of acetaldehyde in [Bmpy][NTf 2 ] in the presence of oxygen and trace water can be controlled by electrochemical potentials. By controlling the electrode potential windows, several methods including cyclic voltammetry, potential step methods (single-potential, double-potential and triple-potential step methods) were established for the quantification of acetaldehyde. Instead of treating water and oxygen as frustrating interferents to ILs, we found that oxygen and trace water chemistry in [Bmpy][NTf 2 ] can be utilized to develop innovative electrochemical methods for electroanalysis of acetaldehyde.

Susceptibility of Trichophyton quinckeanum and Trichophyton rubrum to products of oxidative metabolism.

PubMed

Calderon, R A; Shennan, G I

1987-07-01

Two dermatophyte strains, Trichophyton quinckeanum and Trichophyton rubrum, were highly susceptible to in vitro killing by components of the H2O2-peroxidase-halide system. Both strains were, however, resistant to relatively high concentrations of reagent H2O2 or H2O2 enzymatically generated by glucose and glucose oxidase, KI, or lactoperoxidase (LPO) alone. Resistance to hydrogen peroxidase killing was found to be in part due to the presence of endogenous catalase in the fungi; susceptibility was increased by pretreatment of the fungi with a catalase inhibitor. Kinetic studies using small quantities of reagent or enzymatically generated H2O2 and LPO-KI showed that the system was lethal for both fungal strains within 1 min. Furthermore, using the glucose-glucose oxidase-LPO-KI system, it was shown that catalase, superoxide dismutase and histidine scavengers of H2O2, superoxide anion and singlet oxygen, respectively, prevented the killing of fungus, whereas scavengers of hydroxyl radicals such as benzoate and mannitol had no effect. T. quinckeanum was found to contain large quantities of superoxide anion, as judged by the nitroblue-tetrazolium test. Consequently, the xanthine (or hypoxanthine) and xanthine oxidase system in which the main product is superoxide anion had no toxic effect on the fungus. The high sensitivity of dermatophytes to killing by the H2O2-peroxidase-halide system active in polymorphonuclear neutrophils and macrophages may account in part for fungal toxicity in vivo.

Anti-inflammatory effects of secondary metabolites of marine Pseudomonas sp. in human neutrophils are through inhibiting P38 MAPK, JNK, and calcium pathways.

PubMed

Yang, Shun-Chin; Sung, Ping-Jyun; Lin, Chwan-Fwu; Kuo, Jimmy; Chen, Chun-Yu; Hwang, Tsong-Long

2014-01-01

Activated neutrophils play a significant role in the pathogenesis of many inflammatory diseases. The metabolites of marine microorganisms are increasingly employed as sources for developing new drugs; however, very few marine drugs have been studied in human neutrophils. Herein, we showed that secondary metabolites of marine Pseudomonas sp. (N11) significantly inhibited superoxide anion generation and elastase release in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-activated human neutrophils, with IC50 values of 0.67±0.38 µg/ml and 0.84±0.12 µg/ml, respectively. In cell-free systems, neither superoxide anion-scavenging effect nor inhibition of elastase activity was associated with the suppressive effects of N11. N11 inhibited the phosphorylation of p38 MAP kinase and JNK, but not Erk and Akt, in FMLP-induced human neutrophils. Also, N11 dose-dependently attenuated the transient elevation of intracellular calcium concentration in activated neutrophils. In contrast, N11 failed to alter phorbol myristate acetate-induced superoxide anion generation, and the inhibitory effects of N11 were not reversed by protein kinase A inhibitor. In conclusion, the anti-inflammatory effects of N11 on superoxide anion generation and elastase release in activated human neutrophils are through inhibiting p38 MAP kinase, JNK, and calcium pathways. Our results suggest that N11 has the potential to be developed to treat neutrophil-mediated inflammatory diseases.

Salicylate Treatment Improves Age-Associated Vascular Endothelial Dysfunction: Potential Role of Nuclear Factor κB and Forkhead Box O Phosphorylation

PubMed Central

Durrant, Jessica R.; Connell, Melanie L.; Folian, Brian J.; Donato, Anthony J.; Seals, Douglas R.

2011-01-01

We hypothesized that I kappa B kinase (IKK)-mediated nuclear factor kappa B and forkhead BoxO3a phosphorylation will be associated with age-related endothelial dysfunction. Endothelium-dependent dilation and aortic protein expression/phosphorylation were determined in young and old male B6D2F1 mice and old mice treated with the IKK inhibitor, salicylate. IKK activation was greater in old mice and was associated with greater nitrotyrosine and cytokines. Endothelium-dependent dilation, nitric oxide (NO), and endothelial NO synthase phosphorylation were lower in old mice. Endothelium-dependent dilation and NO bioavailability were restored by a superoxide dismutase mimetic. Nuclear factor kappa B and forkhead BoxO3a phosphorylation were greater in old and were associated with increased expression/activity of nicotinamide adenine dinucleotide phosphate oxidase and lower manganese superoxide dismutase expression. Salicylate lowered IKK phosphorylation and reversed age-associated changes in nitrotyrosine, endothelium-dependent dilation, NO bioavailability, endothelial NO synthase, nuclear factor kappa B and forkhead BoxO3a phosphorylation, nicotinamide adenine dinucleotide phosphate oxidase, and manganese superoxide dismutase. Increased activation of IKK with advancing age stimulates nuclear factor kappa B and inactivates forkhead BoxO3a. This altered transcription factor activation contributes to a pro-inflammatory/pro-oxidative arterial phenotype that is characterized by increased cytokines and nicotinamide adenine dinucleotide phosphate oxidase and decreased manganese superoxide dismutase leading to oxidative stress-mediated endothelial dysfunction. PMID:21303813

Dysregulation of mitochondrial calcium signaling and superoxide flashes cause mitochondrial genomic DNA damage in Huntington disease.

PubMed

Wang, Jiu-Qiang; Chen, Qian; Wang, Xianhua; Wang, Qiao-Chu; Wang, Yun; Cheng, He-Ping; Guo, Caixia; Sun, Qinmiao; Chen, Quan; Tang, Tie-Shan

2013-02-01

Huntington disease (HD) is an inherited, fatal neurodegenerative disorder characterized by the progressive loss of striatal medium spiny neurons. Indications of oxidative stress are apparent in brain tissues from both HD patients and HD mouse models; however, the origin of this oxidant stress remains a mystery. Here, we used a yeast artificial chromosome transgenic mouse model of HD (YAC128) to investigate the potential connections between dysregulation of cytosolic Ca(2+) signaling and mitochondrial oxidative damage in HD cells. We found that YAC128 mouse embryonic fibroblasts exhibit a strikingly higher level of mitochondrial matrix Ca(2+) loading and elevated superoxide generation compared with WT cells, indicating that both mitochondrial Ca(2+) signaling and superoxide generation are dysregulated in HD cells. The excessive mitochondrial oxidant stress is critically dependent on mitochondrial Ca(2+) loading in HD cells, because blocking mitochondrial Ca(2+) uptake abolished elevated superoxide generation. Similar results were obtained using neurons from HD model mice and fibroblast cells from HD patients. More importantly, mitochondrial Ca(2+) loading in HD cells caused a 2-fold higher level of mitochondrial genomic DNA (mtDNA) damage due to the excessive oxidant generation. This study provides strong evidence to support a new causal link between dysregulated mitochondrial Ca(2+) signaling, elevated mitochondrial oxidant stress, and mtDNA damage in HD. Our results also indicate that reducing mitochondrial Ca(2+) uptake could be a therapeutic strategy for HD.

Electrode Reactions Coupled with Chemical Reactions of Oxygen, Water and Acetaldehyde in an Ionic Liquid: New Approaches for Sensing Volatile Organic Compounds

PubMed Central

Chi, Xiaowei; Tang, Yongan; Zeng, Xiangqun

2017-01-01

Water and oxygen are ubiquitous present in ambient conditions. This work studies the unique oxygen, trace water and a volatile organic compound (VOC) acetaldehyde redox chemistry in a hydrophobic and aprotic ionic liquid (IL), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([Bmpy] [NTf2]) by cyclic voltammetry and potential step methods. One electron oxygen reduction leads to superoxide radical formation in the IL. Trace water in the IL acts as a protic species that reacts with the superoxide radical. Acetaldehyde is a stronger protic species than water for reacting with the superoxide radical. The presence of trace water in the IL was also demonstrated to facilitate the electro-oxidation of acetaldehyde, with similar mechanism to that in the aqueous solutions. A multiple-step coupling reaction mechanism between water, superoxide radical and acetaldehyde has been described. The unique characteristics of redox chemistry of acetaldehyde in [Bmpy][NTf2] in the presence of oxygen and trace water can be controlled by electrochemical potentials. By controlling the electrode potential windows, several methods including cyclic voltammetry, potential step methods (single-potential, double-potential and triple-potential step methods) were established for the quantification of acetaldehyde. Instead of treating water and oxygen as frustrating interferents to ILs, we found that oxygen and trace water chemistry in [Bmpy][NTf2] can be utilized to develop innovative electrochemical methods for electroanalysis of acetaldehyde. PMID:29142331

Cu,Zn superoxide dismutase structure from a microbial pathogen establishes a class with a conserved dimer interface.

PubMed

Forest, K T; Langford, P R; Kroll, J S; Getzoff, E D

2000-02-11

Macrophages and neutrophils protect animals from microbial infection in part by issuing a burst of toxic superoxide radicals when challenged. To counteract this onslaught, many Gram-negative bacterial pathogens possess periplasmic Cu,Zn superoxide dismutases (SODs), which act on superoxide to yield molecular oxygen and hydrogen peroxide. We have solved the X-ray crystal structure of the Cu,Zn SOD from Actinobacillus pleuropneumoniae, a major porcine pathogen, by molecular replacement at 1.9 A resolution. The structure reveals that the dimeric bacterial enzymes form a structurally homologous class defined by a water-mediated dimer interface, and share with all Cu,Zn SODs the Greek-key beta-barrel subunit fold with copper and zinc ions located at the base of a deep loop-enclosed active-site channel. Our structure-based sequence alignment of the bacterial enzymes explains the monomeric nature of at least two of these, and suggests that there may be at least one additional structural class for the bacterial SODs. Two metal-mediated crystal contacts yielded our C222(1) crystals, and the geometry of these sites could be engineered into proteins recalcitrant to crystallization in their native form. This work highlights structural differences between eukaryotic and prokaryotic Cu,Zn SODs, as well as similarities and differences among prokaryotic SODs, and lays the groundwork for development of antimicrobial drugs that specifically target periplasmic Cu,Zn SODs of bacterial pathogens. Copyright 12000 Academic Press.

Superoxide (Electro)Chemistry on Well-Defined Surfaces in Organic Environments

DOE PAGES

Genorio, Bostjan; Staszak-Jirkovský, Jakub; Assary, Rajeev S.; ...

2016-02-09

Efficient chemical transformations in energy conversion and storage systems depend on understanding superoxide anion (O 2 –) electrochemistry at atomic and molecular levels. Here, in this work, a combination of experimental and theoretical techniques are used for rationalizing, and ultimately understanding, the complexity of superoxide anion (electro)chemistry in organic environments. By exploring the O 2 + e – ↔ O 2 – reaction on well-characterized metal single crystals (Au, Pt, Ir), Pt single crystal modified with a single layer of graphene (Graphene@Pt(111)), and glassy carbon (GC) in 1,2 dimethoxyethane (DME) electrolytes, we demonstrate that (i) the reaction is an outer-spheremore » process; (ii) the reaction product O 2 – can “attack” any part of the DME molecule, i.e., the C–O bond via nucleophilic reaction and the C–H bond via radical hydrogen abstraction; (iii) the adsorption of carbon-based decomposition products and the extent of formation of a “solid electrolyte interface” (“SEI”) increases in the same order as the reactivity of the substrate, i.e., Pt(hkl)/Ir(hkl) » Au(hkl)/GC > Gaphene@Pt(111); and (iv) the formation of the “SEI” layer leads to irreversible superoxide electrochemistry on Pt(hkl) and Ir(hkl) surfaces. In conclusion, we believe this fundamental insight provides a pathway for the rational design of stable organic solvents that are urgently needed for the development of a new generation of reliable and affordable battery systems.« less

Endotoxin treatment protects rats against ozone-induced lung edema: with evidence for the role of manganese superoxide dismutase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rahman, I.; Massaro, D.

Ozone is a strong oxidizing agent that can cause lung damage and edema. There is evidence that it does so by causing peroxidation of membrane lipids. However, the elevation in lung activity of copper, zinc superoxide dismutase (Cu, ZnSOD), and manganese superoxide dismutase (MnSOD) during exposure to ozone suggests that increased production of superoxide could contribute to lung edema caused by ozone. This latter observation, and preliminary evidence that treatment of rats with endotoxin elevates lung activity of MnSOD without elevation of the activity of Cu, ZnSOD, catalase (CAT), or glutathione peroxidase (GP), led to the present study. We treatedmore » rats with endotoxin, exposed them to different concentrations of ozone, measured lung wet weight to dry weight ratio, thiobarbituric acid-reactive material (TBAR), and assayed lung tissue for Cu, ZnSOD, MnSOD, CAT, and GP activity. Our major findings are, (1) a strongly edemogenic concentration of ozone-lowered MnSOD activity; (2) endotoxin treatment of air-breathing rats did not decrease lipid peroxidation as indicated by the lung concentration of TBAR; (3) induction of increased MnSOD activity in lung by treatment with endotoxin was associated with virtually complete protection against an otherwise edemogenic concentration of ozone, with less lipid peroxidation, and with less loss of weight; and (4) this protection occurred without elevated Cu, ZnSOD, CAT, or GP activity.« less

Mitochondrial redox cycling of mitoquinone leads to superoxide production and cellular apoptosis.

PubMed

Doughan, Abdulrahman K; Dikalov, Sergey I

2007-11-01

The mitochondria-targeted drug mitoquinone (MitoQ) has been used as an antioxidant that may selectively block mitochondrial oxidative damage; however, it has been recently suggested to increase reactive oxygen species (ROS) generation in malate- and glutamate-fueled mitochondria. To address this controversy, we studied the effects of MitoQ on endothelial and mitochondrial ROS production. We found that in a cell-free system with flavin-containing enzyme cytochrome P-450 reductase, MitoQ is a very efficient redox cycling agent and produced more superoxide compared with equal concentrations of menadione (10-1,000 nM). Treatment of endothelial cells with MitoQ resulted in a dramatic increase in superoxide production. In isolated mitochondria, MitoQ increased complex I-driven mitochondrial ROS production, whereas supplementation with ubiquinone-10 had no effect on ROS production. Similar results were observed in mitochondria isolated from endothelial cells incubated for 1 h with MitoQ. Inhibitor analysis suggested that the redox cycling of MitoQ occurred at two sites on complex I, proximal and distal to the rotenone-binding site. This was confirmed by demonstrating the redox cycling of MitoQ on purified mitochondrial complex I as well as NADH-fueled submitochondrial particles. Mitoquinone time- and dose-dependently increased endothelial cell apoptosis. These findings demonstrate that MitoQ may be prooxidant and proapoptotic because its quinone group can participate in redox cycling and superoxide production. In light of these results, studies using mitoquinone as an antioxidant should be interpreted with caution.

Quantitative determination of superoxide in plant leaves using a modified NBT staining method.

PubMed

Bournonville, Carlos F Grellet; Díaz-Ricci, Juan Carlos

2011-01-01

In plants, the ROS (reactive oxygen species) level is tightly regulated because their accumulation produces irreversible damage leading to cell death. However, ROS accumulation plays a key role in plant signaling under biotic or abiotic stress. Although various methods were reported to evaluate ROS accumulation, they are restricted to model plants or provide only qualitative information. Develop a simple method to quantify superoxide radicals produced in plant tissues, based on the selective extraction of the formazan produced after nitroblue tetrazolium (NBT) reduction in histochemical staining. Plant leaves were stained with a standard NBT method and the formazan precipitated in tissues was selectively extracted using chloroform. The organic phase was dried and formazan residue dissolved in dimethylsulfoxide-potassium hydroxide and quantified by spectrophotometry. The method was tested in strawberry plant leaves under different stressing conditions. Formazan extracted from leaves subjected to stress conditions showed similar absorption spectra to those obtained from standard solutions using pure formazan. Calibration curves showed a linear relationship between absorbance and formazan amounts, within the range 0.5-8 µg. Outcomes suggested that formazan was retained in the solid residue of leaf tissues. This protocol allowed us to quantify superoxide radicals produced under different stress conditions. Chloroform allowed a selective formazan extraction and removal of potential endogenous, exogenous or procedural artefacts that may interfere with the quantitative determination. This protocol can be used to quantify the superoxide produced in plant tissues using any traditional qualitative NBT histochemical staining method. Copyright © 2011 John Wiley & Sons, Ltd.

[Standardization and regulation of the rate of the superoxide-generating adrenaline autoxidation reaction used for evaluation of pro/antioxidant properties of various materials].

PubMed

Sirota, T V

2016-11-01

The superoxide-generating reaction of adrenaline autoxidation is widely used for determination of the activity of superoxide dismutase and pro/antioxidant properties of various materials. There are two variants of the spectrophotometric registration of the products of this reaction. The first is based on registration of adrenochrome, as adrenaline autooxidation product at 347 nm; the second employs nitro blue tetrazolium (NBT) and registration of diformazan, a product of NBT reduction at 560 nm. In the present work, recommendations for the standardization of the reaction rate in both variants have been proposed. The main approach consists in the use of the pharmaceutical form of 0.1% adrenaline hydrochloride solution. Although each of two adrenaline preparations available in the Russian market has some features in kinetic behavior of its autooxidation; they are applicable in the superoxide generating system based on adrenaline autooxidation. Performing measurements at 560 nm, the reaction rate can be regulated by lowering the concentration of added adrenaline, whereas during spectrophotometric registration at 347 nm, this cannot be done. These features of adrenaline autoxidation may be due to the fact that the intrinsic multistage process of the conversion of adrenaline to adrenochrome, which is recorded at 347 nm, is coupled with the transition of electrons from adrenaline and intermediate products of its oxidation to oxygen, carbon dioxide, and carbonate bicarbonate ions, which is detected in the presence of added NBT.

Uncaria rhynchophylla and Rhynchophylline inhibit c-Jun N-terminal kinase phosphorylation and nuclear factor-kappaB activity in kainic acid-treated rats.

PubMed

Hsieh, Ching-Liang; Ho, Tin-Yun; Su, Shan-Yu; Lo, Wan-Yu; Liu, Chung-Hsiang; Tang, Nou-Ying

2009-01-01

Our previous studies have shown that Uncaria rhynchophylla (UR) can reduce epileptic seizures. We hypothesized that UR and its major component rhynchophylline (RH), reduce epileptic seizures in rats treated with kainic acid (KA) by inhibiting nuclear factor-kappaB (NF-kappaB) and activator-protein-1 (AP-1) activity, and by eliminating superoxide anions. Therefore, the level of superoxide anions and the DNA binding activities of NF-kappaB and AP-1 were measured. Sprague-Dawley (SD) rats were pre-treated with UR (1.0 g/kg, i.p.), RH (0.25 mg/kg, i.p.), or valproic acid (VA, 250 mg/kg, i.p.) for 3 days and then KA was administered intra-peritoneal (i.p.). The results indicated that UR, RH, and VA can reduce epileptic seizures and the level of superoxide anions in the blood. Furthermore, KA was demonstrated to induce the DNA binding activities of NF-kappaB and AP-1. However, these inductions were inhibited by pre-treatment with UR, RH, or VA for 3 days. Moreover, UR and RH were shown to be involved in the suppression of c-Jun N-terminal kinase (JNK) phosphorylation. This study suggested that UR and RH have antiepileptic effects in KA-induced seizures and are associated with the regulation of the innate immune system via a reduction in the level of superoxide anions, JNK phosphorylation, and NF-kappaB activation.

The human Krebs cycle 2-oxoglutarate dehydrogenase complex creates an additional source of superoxide/hydrogen peroxide from 2-oxoadipate as alternative substrate.

PubMed

Nemeria, Natalia S; Gerfen, Gary; Guevara, Elena; Nareddy, Pradeep Reddy; Szostak, Michal; Jordan, Frank

2017-07-01

Recently, we reported that the human 2-oxoglutarate dehydrogenase (hE1o) component of the 2-oxoglutarate dehydrogenase complex (OGDHc) could produce the reactive oxygen species superoxide and hydrogen peroxide (detected by chemical means) from its substrate 2-oxoglutarate (OG), most likely concurrently with one-electron oxidation by dioxygen of the thiamin diphosphate (ThDP)-derived enamine intermediate to a C2α-centered radical (detected by Electron Paramagnetic Resonance) [Nemeria et al., 2014 [17]; Ambrus et al. 2015 [18

The preparation of calcium superoxide at subambient temperatures and pressures. [oxygen source for breathing apparatus

NASA Technical Reports Server (NTRS)

Ballou, E. V.; Wood, P. C.; Spitze, L. A.; Wydeven, T.; Stein, R.

1977-01-01

The effects of disproportionations at lower temperatures and also of a range of reaction chamber pressures on the preparation of calcium superoxide, Ca(O2)2, from calcium peroxide diperoxyhydrate were studied. About 60% purity of product was obtained by a disproportionation procedure. The significance of features of this procedure for a prospective scale-up of the mass prepared in a single experiment is considered. The optimum pressure for product purity was determined, and the use of a molecular sieve desiccant is described.

Lung Macrophages “Digest” Carbon Nanotubes Using a Superoxide/Peroxynitrite Oxidative Pathway

PubMed Central

2015-01-01

In contrast to short-lived neutrophils, macrophages display persistent presence in the lung of animals after pulmonary exposure to carbon nanotubes. While effective in the clearance of bacterial pathogens and injured host cells, the ability of macrophages to “digest” carbonaceous nanoparticles has not been documented. Here, we used chemical, biochemical, and cell and animal models and demonstrated oxidative biodegradation of oxidatively functionalized single-walled carbon nanotubes via superoxide/NO* → peroxynitrite-driven oxidative pathways of activated macrophages facilitating clearance of nanoparticles from the lung. PMID:24871084

The Protective Roles of the Antioxidant Enzymes Superoxide Dismutase and Catalase in the Green Photosynthetic Bacterium Chloroflexus Aurantiacus

NASA Technical Reports Server (NTRS)

Blankenship, Robert E.; Rothschild, Lynn (Technical Monitor)

2004-01-01

The purpose of this study was to examine the biochemical response of the green thermophilic photosynthetic bacterium Chloroflexus aurantiacus to oxidative stress. Lab experiments focused primarily on characterizing the antioxidant enzyme superoxide dismutase and the response of this organism to oxidative stress. Experiments in the field at the hotsprings in Yellowstone National Park focused on the changes in the level of these enzymes during the day in response to oxidants and to the different types of ultraviolet radiation.

Bioassay-comparison of the antioxidant efficacy of hydrogen sulfide and superoxide dismutase in isolated arteries and veins.

PubMed

Hamar, J; Solymár, M; Tanai, E; Cseplo, P; Springo, Zs; Berta, G; Debreceni, B; Koller, Akos

2012-12-01

Recent studies suggest that hydrogen sulfide (H2S) exhibits potent antioxidant capacity and improves vascular and tissue functions. Thus we aimed to compare the antioxidant efficacy of H2S to that of superoxide dismutase (SOD).Isometric force of isolated rat carotid arteries and gracilis veins was measured with a myograph. The vasomotor effect of the superoxide-generator pyrogallol (10-5M) was obtained in control conditions, and then in the presence of SOD (120 U/ml) or H2S (10-5M or 10-4M), respectively. Spectrophotometric measurements were performed to detect the effect of SOD and H2S on the auto-oxidation of pyrogallol.Pyrogallol increased the isometric force of carotid arteries (9.7 ± 0.8 mN), which was abolished by SOD (5.3 ± 0.8 mN), was not affected by 10-5M H2S (9.1 ± 0.5 mN), whereas 10-4M H2S slightly, but significantly reduced it (8.1 ± 0.7 mN). Pyrogallol significantly increased the isometric force of gracilis veins (1.3 ± 0.2 mN), which was abolished by SOD (0.9 ± 0.2 mN), whereas 10-5M (1.3 ± 0.2 mN), or 10-4M H2S (1.2 ± 0.2 mN) did not affect it. Pyrogallol-induced superoxide production was measured by a spectrophotometer (A420 = 0.19 ± 0.0). SOD reduced absorbance (A420 = 0.02 ± 0.0), whereas 10-5M H2S did not (A420 = 0.18 ± 0.0) and 10-4M H2S slightly reduced it (A420 = 0.15 ± 0.0).These data suggest that H2S is a less effective vascular antioxidant than SOD. We propose that the previously described beneficial effects of H2S are unlikely to be related to its direct effect on superoxide.

Superoxide produced in the matrix of mitochondria enhances methylmercury toxicity in human neuroblastoma cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mailloux, Ryan J.; Yumvihoze, Emmanuel; Chan, Hing Man, E-mail: laurie.chan@uottawa.ca

2015-12-15

The mechanism of intracellular metabolism of methylmercury (MeHg) is not fully known. It has been shown that superoxide (O{sub 2}·{sup −}), the proximal reactive oxygen species (ROS) generated by mitochondria, is responsible for MeHg demethylation. Here, we investigated the impact of different mitochondrial respiratory inhibitors, namely rotenone and antimycin A, on the O{sub 2}·{sup −} mediated degradation of MeHg in human neuroblastoma cells SH-K-SN. We also utilized paraquat (PQ) which generates O{sub 2}·{sup −} in the mitochondrial matrix. We found that the cleavage of the carbon-metal bond in MeHg was highly dependent on the topology of O{sub 2}·{sup −} productionmore » by mitochondria. Both rotenone and PQ, which increase O{sub 2}·{sup −} in the mitochondrial matrix at a dose-dependent manner, enhanced the conversion of MeHg to inorganic mercury (iHg). Surprisingly, antimycin A, which prompts emission of O{sub 2}·{sup −} into the intermembrane space, did not have the same effect even though antimycin A induced a dose dependent increase in O{sub 2}·{sup −} emission. Rotenone and PQ also enhanced the toxicity of sub-toxic doses (0.1 μM) MeHg which correlated with the accumulation of iHg in mitochondria and depletion of mitochondrial protein thiols. Taken together, our results demonstrate that MeHg degradation is mediated by mitochondrial O{sub 2}·{sup −}, specifically within the matrix of mitochondria when O{sub 2}·{sup −} is in adequate supply. Our results also show that O{sub 2}·{sup −} amplifies MeHg toxicity specifically through its conversion to iHg and subsequent interaction with protein cysteine thiols (R-SH). The implications of our findings in mercury neurotoxicity are discussed herein. - Highlights: • Superoxide produced in the matrix of mitochondria degrades MeHg. • Superoxide produced in intermembrane space does not degrade MeHg. • Matrix-generated superoxide enhances Hg toxicity by converting MeHg to iHg.« less

Differentiation by hydroquinone of relaxations induced by exogenous and endogenous nitrates in non-vascular smooth muscle: role of superoxide anions.

PubMed Central

Hobbs, A. J.; Tucker, J. F.; Gibson, A.

1991-01-01

1. The influence of hydroquinone on relaxations induced by nitric oxide (NO), nitrovasodilator drugs, and non-adrenergic, non-cholinergic (NANC) field stimulation has been investigated in three tissues in which endogenous nitrates have been implicated in the NANC response; the mechanism of action of hydroquinone was also studied. 2. In mouse anococcygeus, hydroquinone (10-100 microM) produced a concentration-dependent inhibition of relaxations induced by 15 microM NO. Hydroquinone, 100 microM, which reduced responses to NO by 85%, had no effect on relaxations induced by NANC field stimulation (10 Hz; 20s trains), hydroxylamine (10 microM), sodium nitroprusside (1 microM) or sodium azide (20 microM). 3. In guinea-pig trachea, 100 microM hydroquinone reduced relaxations to 150 microM NO by 75%, but had no effect on those to NANC stimulation (10 Hz; 30 s trains) or sodium azide (5 microM). 4. In rat gastric fundus, 100 microM hydroquinone reduced relaxations to 1 microM NO by 85%, but had no effect on those to NANC stimulation (0.5 Hz; 15 s trains) or sodium azide (2 microM). 5. Superoxide dismutase (SOD; 50 u ml-1) had no effect on relaxations of the mouse anococcygeus in response to 15 microM NO or 10 Hz NANC stimulation. Further, the inhibition of responses to NO by hydroquinone was unaffected in the presence of SOD. 6. Hydroquinone (10-100 microM) failed to generate superoxide anions, as detected by a chemiluminescent assay. However, 100 microM hydroquinone, like SOD (50 u ml-1), produced almost complete inhibition of superoxide anion chemiluminescence induced by xanthine (500 microM): xanthine oxidase (0.07 u ml-1). 7. It is concluded that, in our system, hydroquinone inhibits NO by acting as a free radical scavenger rather than by generating superoxide anions. The ability of hydroquinone to block relaxations to NO, but not NANC stimulation, may suggest that the endogenous nitrate substance released by these NANC nerves may not be free NO, but may be an NO-containing, or NO-generating, molecule. PMID:1665746

PCB153 reduces telomerase activity and telomere length in immortalized human skin keratinocytes (HaCaT) but not in human foreskin keratinocytes (NFK)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Senthilkumar, P.K.; Robertson, L.W.; Department of Occupational and Environmental Health, The University of Iowa, Iowa City, IA

Polychlorinated biphenyls (PCBs), ubiquitous environmental pollutants, are characterized by long term-persistence in the environment, bioaccumulation, and biomagnification in the food chain. Exposure to PCBs may cause various diseases, affecting many cellular processes. Deregulation of the telomerase and the telomere complex leads to several biological disorders. We investigated the hypothesis that PCB153 modulates telomerase activity, telomeres and reactive oxygen species resulting in the deregulation of cell growth. Exponentially growing immortal human skin keratinocytes (HaCaT) and normal human foreskin keratinocytes (NFK) were incubated with PCB153 for 48 and 24 days, respectively, and telomerase activity, telomere length, superoxide level, cell growth, and cellmore » cycle distribution were determined. In HaCaT cells exposure to PCB153 significantly reduced telomerase activity, telomere length, cell growth and increased intracellular superoxide levels from day 6 to day 48, suggesting that superoxide may be one of the factors regulating telomerase activity, telomere length and cell growth compared to untreated control cells. Results with NFK cells showed no shortening of telomere length but reduced cell growth and increased superoxide levels in PCB153-treated cells compared to untreated controls. As expected, basal levels of telomerase activity were almost undetectable, which made a quantitative comparison of treated and control groups impossible. The significant down regulation of telomerase activity and reduction of telomere length by PCB153 in HaCaT cells suggest that any cell type with significant telomerase activity, like stem cells, may be at risk of premature telomere shortening with potential adverse health effects for the affected organism. -- Highlights: ► Human immortal (HaCaT) and primary (NFK) keratinocytes were exposed to PCB153. ► PCB153 significantly reduced telomerase activity and telomere length in HaCaT. ► No effect on telomere length and telomerase activity was found in NFK. ► Increased intracellular superoxide levels and reduced cell growth was seen in both. ► PCB153 may damage telomerase expressing cells like stem cells.« less

Biochemical modifications in Pinus pinaster Ait. as a result of environmental pollution.

PubMed

Acquaviva, Rosaria; Vanella, Luca; Sorrenti, Valeria; Santangelo, Rosa; Iauk, Liliana; Russo, Alessandra; Savoca, Francesca; Barbagallo, Ignazio; Di Giacomo, Claudia

2012-11-01

Exposure to chemical pollution can cause significant damage to plants by imposing conditions of oxidative stress. Plants combat oxidative stress by inducing antioxidant metabolites, enzymatic scavengers of activated oxygen and heat shock proteins. The accumulation of these proteins, in particular heat shock protein 70 and heme oxygenase, is correlated with the acquisition of thermal and chemical adaptations and protection against oxidative stress. In this study, we used Pinus pinaster Ait. collected in the areas of Priolo and Aci Castello representing sites with elevated pollution and reference conditions, respectively. The presence of heavy metals and the levels of markers of oxidative stress (lipid hydroperoxide levels, thiol groups, superoxide dismutase activity and expression of heat shock protein 70, heme oxygenase and superoxide dismutase) were evaluated, and we measured in field-collected needles the response to environmental pollution. P. pinaster Ait. collected from a site characterized by industrial pollution including heavy metals had elevated stress response as indicated by significantly elevated lipid hydroperoxide levels and decreased thiol groups. In particular, we observed that following a chronic chemical exposure, P. pinaster Ait. showed significantly increased expression of heat shock protein 70, heme oxygenase and superoxide dismutase. This increased expression may have protective effects against oxidative stress and represents an adaptative cellular defence mechanism. These results suggest that evaluation of heme oxygenase, heat shock protein 70 and superoxide dismutase expression in P. pinaster Ait. could represent a useful tool for monitoring environmental contamination of a region and to better understand mechanisms involved in plant defence and stress tolerance.

Sites of superoxide and hydrogen peroxide production by muscle mitochondria assessed ex vivo under conditions mimicking rest and exercise.

PubMed

Goncalves, Renata L S; Quinlan, Casey L; Perevoshchikova, Irina V; Hey-Mogensen, Martin; Brand, Martin D

2015-01-02

The sites and rates of mitochondrial production of superoxide and H2O2 in vivo are not yet defined. At least 10 different mitochondrial sites can generate these species. Each site has a different maximum capacity (e.g. the outer quinol site in complex III (site IIIQo) has a very high capacity in rat skeletal muscle mitochondria, whereas the flavin site in complex I (site IF) has a very low capacity). The maximum capacities can greatly exceed the actual rates observed in the absence of electron transport chain inhibitors, so maximum capacities are a poor guide to actual rates. Here, we use new approaches to measure the rates at which different mitochondrial sites produce superoxide/H2O2 using isolated muscle mitochondria incubated in media mimicking the cytoplasmic substrate and effector mix of skeletal muscle during rest and exercise. We find that four or five sites dominate during rest in this ex vivo system. Remarkably, the quinol site in complex I (site IQ) and the flavin site in complex II (site IIF) each account for about a quarter of the total measured rate of H2O2 production. Site IF, site IIIQo, and perhaps site EF in the β-oxidation pathway account for most of the remainder. Under conditions mimicking mild and intense aerobic exercise, total production is much less, and the low capacity site IF dominates. These results give novel insights into which mitochondrial sites may produce superoxide/H2O2 in vivo. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Role of superoxide radical anion in the mechanism of apoB100 degradation induced by DHA in hepatic cells

PubMed Central

Andreo, Ursula; Elkind, Josh; Blachford, Courtney; Cederbaum, Arthur I.; Fisher, Edward A.

2011-01-01

VLDL is produced by the liver. Its major protein is apoB100. Docosahexaenoic acid (DHA), a dietary polyunsaturated fatty acid (PUFA), reduces VLDL levels and is used therapeutically for hypertriglyceridemia. In model systems, DHA lowers VLDL secretion by inducing presecretory apoB100 degradation, a process dependent on PUFA-derived lipid peroxides. We hypothesized that superoxide (SO) was a major participant in DHA-induced apoB100 degradation, given its promotion of lipid peroxidation. SO levels in a model of VLDL metabolism, rat hepatoma McArdle cells, were either decreased by a mimetic of superoxide dismutase 1 (SOD1) or by overexpressing SOD1 or increased by SOD1 siRNA. ApoB100 recovery was assessed by immunoprecipitation, SO by 2-hydroxyethidine, and lipid peroxides by thiobarbituric acid reactive substances. The SOD1 mimetic or SOD1 overexpression reduced SO and inhibited apoB100 degradation in DHA-treated cells by up to 100%. Surprisingly, silencing SOD1 did not increase DHA-induced degradation, although levels of SO were higher (+44%); those of lipid peroxides were similar, and their reduction by α-tocopherol decreased degradation by 50%. SO is required for lipid peroxidation in DHA-induced apoB100 degradation, but it is the peroxide level that has a tighter relationship to the level of degradation and the regulation of VLDL production.—Andreo, U., Elkind, J., Blachford, C., Cederbaum, A. I., Fisher, E. A. Role of superoxide radical anion in the mechanism of apoB100 degradation induced by DHA in hepatic cells. PMID:21757500

Oxidative stress induced by Porphyromonas gingivalis lysate and nicotine in human periodontal ligament fibroblasts.

PubMed

Nguyen, Thuy Thu; Huynh, Nam Nhat-Cong; Seubbuk, Sujiwan; Nilmoje, Thanapoj; Wanasuntronwong, Aree; Surarit, Rudee

2018-06-29

Porphyromonas gingivalis (P. gingivalis) and nicotine have been implicated as a major pathogen in the development and progression of periodontitis. One of the possible mechanism is via the oxidative stress of human periodontal ligament fibroblasts (PDLF) which lead to the damage of cell viability and function. This study aimed to investigate oxidative stress (OS) levels in the cultured media of human PDLF under the induction of P. gingivalis lysate and nicotine. Primary PDLF was cultured in growth media under P. gingivalis or/and nicotine treatment in different concentrations for 2 and 24 h. Following incubation, oxidative stress molecules malondialdehyde (MDA) and oxidized guanine species (Ox-GS) from the cell cultured supernatant were determined by spectrophotometric assay and ELISA, respectively. DCFDA and superoxide assays were performed to verify the production of ROS and intracellular superoxide radical under various stimuli. As a result, at both 2 and 24 h, Ox-GS and MDA levels in the medium of cells treated with different concentrations of P. gingivalis lysate and nicotine, either separately or in combination, were significantly different from the negative controls in a dose- and time-dependent manner. Interestingly, except MDA levels in P. gingivalis lysate at 20 µg/ml, MDA levels in all other tested conditions were found as same as one in the positive controls after 24 h. ROS and superoxide production were enhanced under P. gingivalis and/or nicotine stimulation. Therefore, OS biomarkers were generated by PDLF upon treatment with periodontal pathogens and nicotine which could elucidate a potential local mechanism of periodontal disease etiology via superoxide mediation.

Sites of Superoxide and Hydrogen Peroxide Production by Muscle Mitochondria Assessed ex Vivo under Conditions Mimicking Rest and Exercise*

PubMed Central

Goncalves, Renata L. S.; Quinlan, Casey L.; Perevoshchikova, Irina V.; Hey-Mogensen, Martin; Brand, Martin D.

2015-01-01

The sites and rates of mitochondrial production of superoxide and H2O2 in vivo are not yet defined. At least 10 different mitochondrial sites can generate these species. Each site has a different maximum capacity (e.g. the outer quinol site in complex III (site IIIQo) has a very high capacity in rat skeletal muscle mitochondria, whereas the flavin site in complex I (site IF) has a very low capacity). The maximum capacities can greatly exceed the actual rates observed in the absence of electron transport chain inhibitors, so maximum capacities are a poor guide to actual rates. Here, we use new approaches to measure the rates at which different mitochondrial sites produce superoxide/H2O2 using isolated muscle mitochondria incubated in media mimicking the cytoplasmic substrate and effector mix of skeletal muscle during rest and exercise. We find that four or five sites dominate during rest in this ex vivo system. Remarkably, the quinol site in complex I (site IQ) and the flavin site in complex II (site IIF) each account for about a quarter of the total measured rate of H2O2 production. Site IF, site IIIQo, and perhaps site EF in the β-oxidation pathway account for most of the remainder. Under conditions mimicking mild and intense aerobic exercise, total production is much less, and the low capacity site IF dominates. These results give novel insights into which mitochondrial sites may produce superoxide/H2O2 in vivo. PMID:25389297

p53-regulated autophagy is controlled by glycolysis and determines cell fate

PubMed Central

Duan, Lei; Perez, Ricardo E.; Davaadelger, Batzaya; Dedkova, Elena N.; Blatter, Lothar A.; Maki, Carl G.

2015-01-01

The tumor suppressor p53 regulates downstream targets that determine cell fate. Canonical p53 functions include inducing apoptosis, growth arrest, and senescence. Non-canonical p53 functions include its ability to promote or inhibit autophagy and its ability to regulate metabolism. The extent to which autophagy and/or metabolic regulation determines cell fate by p53 is unclear. To address this, we compared cells resistant or sensitive to apoptosis by the p53 activator Nutlin-3a. In resistant cells, glycolysis was maintained upon Nutlin-3a treatment, and activated p53 promoted prosurvival autophagy. In contrast, in apoptosis sensitive cells activated p53 increased superoxide levels and inhibited glycolysis through repression of glycolytic pathway genes. Glycolysis inhibition and increased superoxide inhibited autophagy by repressing ATG genes essential for autophagic vesicle maturation. Inhibiting glycolysis increased superoxide and blocked autophagy in apoptosis-resistant cells, causing p62-dependent caspase-8 activation. Finally, treatment with 2-DG or the autophagy inhibitors chloroquine or bafilomycin A1 sensitized resistant cells to Nutlin-3a-induced apoptosis. Together, these findings reveal novel links between glycolysis and autophagy that determine apoptosis-sensitivity in response to p53. Specifically, the findings indicate 1) that glycolysis plays an essential role in autophagy by limiting superoxide levels and maintaining expression of ATG genes required for autophagic vesicle maturation, 2) that p53 can promote or inhibit autophagy depending on the status of glycolysis, and 3) that inhibiting protective autophagy can expand the breadth of cells susceptible to Nutlin-3a induced apoptosis. PMID:26337205

Combined Effects of Lanthanum (III) and Acid Rain on Antioxidant Enzyme System in Soybean Roots.

PubMed

Zhang, Xuanbo; Du, Yuping; Wang, Lihong; Zhou, Qing; Huang, Xiaohua; Sun, Zhaoguo

2015-01-01

Rare earth element pollution (REEs) and acid rain (AR) pollution simultaneously occur in many regions, which resulted in a new environmental issue, the combined pollution of REEs and AR. The effects of the combined pollution on the antioxidant enzyme system of plant roots have not been reported. Here, the combined effects of lanthanum ion (La3+), one type of REE, and AR on the antioxidant enzyme system of soybean roots were investigated. In the combined treatment of La3+ (0.08 mM) and AR, the cell membrane permeability and the peroxidation of cell membrane lipid of soybean roots increased, and the superoxide dismutase, catalase, peroxidase and reduced ascorbic acid served as scavengers of reactive oxygen species. In other combined treatments of La3+ (0.40 mM, 1.20 mM) and AR, the membrane permeability, malonyldialdehyde content, superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content increased, while the catalase activity decreased. The increased superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content were inadequate to scavenge the excess hydrogen peroxide and superoxide, leading to the damage of the cell membrane, which was aggravated with the increase in the concentration of La3+ and the level of AR. The deleterious effects of the combined treatment of La3+ and AR were stronger than those of the single treatment of La3+ or AR. Moreover, the activity of antioxidant enzyme system in the combined treatment group was affected directly and indirectly by mineral element content in soybean plants.

GPER modulates tone and coronary vascular reactivity in male and female rats.

PubMed

Debortoli, Angelina Rafaela; Rouver, Wender do Nascimento; Delgado, Nathalie Tristão Banhos; Mengal, Vinicius; Claudio, Erick Roberto Gonçalves; Pernomian, Laena; Bendhack, Lusiane Maria; Moysés, Margareth Ribeiro; Santos, Roger Lyrio Dos

2017-08-01

Compared with age-matched men, premenopausal women are largely protected from coronary artery disease, a difference that is lost after menopause. The effects of oestrogens are mediated by the activation of nuclear receptors (ERα and ERβ) and by the G protein-coupled oestrogen receptor (GPER). This study aims to evaluate the potential role of GPER in coronary circulation in female and male rats. The baseline coronary perfusion pressure (CPP) and the concentration-response curve with a GPER agonist (G-1) were evaluated in isolated hearts before and after the blockade of GPER. GPER, superoxide dismutase (SOD-2), catalase and gp91phox protein expression were assessed by Western blotting. Superoxide production was evaluated ' in situ ' via dihydroethidium fluorescence (DHE). GPER blockade significantly increased the CPP in both groups, demonstrating the modulation of coronary tone by GPER. G-1 causes relaxation of the coronary bed in a concentration-dependent manner and was significantly higher in female rats. No differences were detected in GPER, SOD-2 and catalase protein expression. However, gp91phox expression and DHE fluorescence were higher in male rats, indicating elevated superoxide production. Therefore, GPER plays an important role in modulating coronary tone and reactivity in female and male rats. The observed differences in vascular reactivity may be related to the higher superoxide production in male rats. These findings help to elucidate the role of GPER-modulating coronary circulation, providing new information to develop a potential therapeutic target for the treatment of coronary heart disease. © 2017 Society for Endocrinology.

Combined Effects of Lanthanum (III) and Acid Rain on Antioxidant Enzyme System in Soybean Roots

PubMed Central

Zhang, Xuanbo; Du, Yuping; Wang, Lihong; Zhou, Qing; Huang, Xiaohua; Sun, Zhaoguo

2015-01-01

Rare earth element pollution (REEs) and acid rain (AR) pollution simultaneously occur in many regions, which resulted in a new environmental issue, the combined pollution of REEs and AR. The effects of the combined pollution on the antioxidant enzyme system of plant roots have not been reported. Here, the combined effects of lanthanum ion (La3+), one type of REE, and AR on the antioxidant enzyme system of soybean roots were investigated. In the combined treatment of La3+ (0.08 mM) and AR, the cell membrane permeability and the peroxidation of cell membrane lipid of soybean roots increased, and the superoxide dismutase, catalase, peroxidase and reduced ascorbic acid served as scavengers of reactive oxygen species. In other combined treatments of La3+ (0.40 mM, 1.20 mM) and AR, the membrane permeability, malonyldialdehyde content, superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content increased, while the catalase activity decreased. The increased superoxide dismutase activity, peroxidase activity and reduced ascorbic acid content were inadequate to scavenge the excess hydrogen peroxide and superoxide, leading to the damage of the cell membrane, which was aggravated with the increase in the concentration of La3+ and the level of AR. The deleterious effects of the combined treatment of La3+ and AR were stronger than those of the single treatment of La3+ or AR. Moreover, the activity of antioxidant enzyme system in the combined treatment group was affected directly and indirectly by mineral element content in soybean plants. PMID:26230263

Featured Article: Effect of copper on nuclear translocation of copper chaperone for superoxide dismutase-1

PubMed Central

Wang, Lin; Ge, Yan

2016-01-01

Copper chaperone for superoxide dismutase-1 (CCS-1), facilitating copper insertion into superoxide dismutase 1 (SOD-1), is present in the nucleus. However, it is unknown how CCS-1 is translocated to the nucleus. The present study was undertaken to determine the effect of copper on nuclear translocation of CCS-1. Human umbilical vein endothelial cells (HUVECs) were subjected to hypoxia, causing an increase in both copper and CCS-1 in the nucleus. Treatment with tetraethylenepentamine (TEPA) not only decreased the total cellular concentration and the nuclear translocation of copper, but also completely suppressed the entry of CCS-1 to the nucleus. On the other hand, siRNA targeting CCS-1 neither inhibited the increase in total concentrations nor blocked the nuclear translocation of copper. This study thus demonstrates that under hypoxia condition, both copper and CCS-1 are transported to the nucleus. The nuclear translocation of CCS-1 is copper dependent, but the nuclear translocation of copper could take place alternatively in a CCS-1-independent pathway. PMID:27190267

Aerobic photoreactivity of synthetic eumelanins and pheomelanins: generation of singlet oxygen and superoxide anion.

PubMed

Szewczyk, Grzegorz; Zadlo, Andrzej; Sarna, Michal; Ito, Shosuke; Wakamatsu, Kazumasa; Sarna, Tadeusz

2016-11-01

In this work, we examined photoreactivity of synthetic eumelanins, formed by autooxidation of DOPA, or enzymatic oxidation of 5,6-dihydroxyindole-2-carboxylic acid and synthetic pheomelanins obtained by enzymatic oxidation of 5-S-cysteinyldopa or 1:1 mixture of DOPA and cysteine. Electron paramagnetic resonance oximetry and spin trapping were used to measure oxygen consumption and formation of superoxide anion induced by irradiation of melanin with blue light, and time-resolved near-infrared luminescence was employed to determine the photoformation of singlet oxygen between 300 and 600 nm. Both superoxide anion and singlet oxygen were photogenerated by the synthetic melanins albeit with different efficiency. At 450-nm, quantum yield of singlet oxygen was very low (~10 -4 ) but it strongly increased in the UV region. The melanins quenched singlet oxygen efficiently, indicating that photogeneration and quenching of singlet oxygen may play an important role in aerobic photochemistry of melanin pigments and could contribute to their photodegradation and photoaging. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Vernonia cinerea L. scavenges free radicals and regulates nitric oxide and proinflammatory cytokines profile in carrageenan induced paw edema model.

PubMed

Kumar, P Pratheesh; Kuttan, Girija

2009-01-01

In this study, we evaluated the anti-oxidant and anti-inflammatory activities of the medicinal plant, Vernonia cinerea L (Asteraceae) using in vitro as well as in vivo models. Methanolic extract of Vernonia cinerea was found to scavenge the hydroxyl radical generated by Fenton reaction (IC(50)130 microg/ml), Superoxide generated by photo reduction of riboflavin (IC(50)190 microg/ml) and inhibited lipid peroxidation significantly (IC(50)130.5 microg/ml). The drug also scavenged nitric oxide (IC(50)210 microg/ml). Intraperitoneal administration of Vernonia cinerea was found to inhibit the PMA induced Superoxide generation in mice peritoneal macrophages. The administration of Vernonia cinerea to mice significantly increased the levels of catalase, superoxide dismutase, glutathione, glutathione peroxidase and glutathione-S transferase in blood and liver, whereas lipid peroxidation activity was significantly decreased. It was also found that Vernonia cinerea extract significantly inhibited carrageenan induced inflammation, compared with control models. Down regulation of pro-inflammatory cytokine level and gene expression were also support the above result.

Effects of N-acetylcysteine and L-arginine in the antioxidant system of C2C12 cells.

PubMed

Da Silva, E P; Lambertucci, R H

2015-06-01

The aim of this study was to evaluate the effects of N-acetylcysteine or L-arginine in the antioxidant system of skeletal muscle cells in culture. We used C2C12 cells which were supplemented or not with N-acetylcysteine or L-arginine at different time points. Antioxidant enzymes' activities and protein expression were evaluated. Additionally, superoxide production by cytochrome c reduction method was carried out. It was observed that the supplementation with either N-acetylcysteine or L-arginine was capable to acutely reduce superoxide production (after 30 and 60 minutes). Surprisingly, N-acetylcysteine supplementation also induced an increased production of superoxide during the period of 24 hours. Moreover, both supplements were capable to improve the activity and protein expression of some antioxidants enzymes. In conclusion, we have found new evidences showing that N-acetylcysteine or L-arginine supplementation can provide some benefits to the antioxidant system of skeletal muscle cells in culture. Further studies have to be carried out to evaluate if such benefits could also occur in an in vivo model, with possible benefits for athletes' health and performance.

Effect of intradermal human recombinant copper-zinc superoxide dismutase on random pattern flaps in rats.

PubMed

Schein, Ophir; Westreich, Melvyn; Shalom, Avshalom

2013-09-01

Studies have focused on enhancing flap viability using superoxide dismutase (SOD), but only a few used SOD from human origin, and most gave the compound systemically. We evaluated the ability of SOD to improve random skin flap survival using human recombinant copper-zinc superoxide dismutase (Hr-CuZnSOD) in variable doses, injected intradermally into the flap. Seventy male Sprague Dawley rats were randomly assigned into 4 groups. Cephalic random pattern flaps were elevated on their backs and intradermal injections of different dosages of Hr-CuZnSOD were given 15 minutes before surgery. Flap survival was evaluated by fluorescein fluorescence. Analysis of variance (ANOVA) and t test statistical analyses were performed. Flap survival in all treated groups was significantly better than in the controls. The beneficial effect of HR-CuZnSOD on flap survival is attained when it is given intradermally into the flap tissue. Theoretically, Hr-CuZnSOD delivered with local anesthetics used in flap elevation may be a valuable clinical tool. Copyright © 2012 Wiley Periodicals, Inc.

Effects of rutin supplementation on antioxidant status and iron, copper, and zinc contents in mouse liver and brain.

PubMed

Gao, Zhonghong; Xu, Huibi; Huang, Kaixun

2002-09-01

The effect of rutin on total antioxidant status as well as on trace elements such as iron, copper, and zinc in mouse liver and brain were studied. Mice were administrated with 0.75 g/kg or 2.25 g/kg P. O. of rutin for 30 d consecutively. Following the treatment, the activity of total antioxidant status, catalase, Cu,Zn-superoxide dismutase, Mn-superoxide dismutase, zinc, copper, and iron were measured in mouse liver and brain. The results showed that rutin significantly increased the antioxidant status and Mn-superoxide dismutase activities in mouse liver, but it had no effect on these variables in the brain. Treatment with a higher concentration of rutin significantly decreased catalase activity and iron, zinc, and copper contents in mouse liver; it also resulted in a slower weight gain for the first 20 d. These results indicate that rutin taken in proper amount can effectively improve antioxidant status, whereas at an increased dosage, it may cause trace element (such as iron, zinc, and copper) deficiencies and a decrease in the activities of related metal-containing enzymes.

Biochemistry of free radicals: from electrons to tissues.

PubMed

Boveris, A

1998-01-01

Free radicals are chemical species with an unpaired electron in the outer valence orbitals. The unpaired electron makes them paramagnetic (physics) and relatively reactive (chemistry). The free radicals that are normal metabolites in aerobic biological systems have varied reactivities, ranging from the high reactivity of hydroxyl radical (t1/2 = 10(-9) s) to the low reactivity of melanins (t1/2 = days). The univalent reduction of oxygen that takes place in mammalian organs produces superoxide radicals at a rate of about 2% of the total oxygen uptake. The primary production of superoxide radicals sustains a free radical chain reaction involving a series of reactive oxygen species (hydrogen peroxide, hydroxyl and peroxyl radical and singlet oxygen). Nitric oxide is almost unreactive as free radical except for its termination reaction with superoxide radical to yield the strong oxidant peroxynitrite. Nitric oxide also reacts with ubiquinol in a redox reaction, with cytochrome oxidase competitively with oxygen, and oxymyoglobin and oxyhemoglobin displacing oxygen. Septic shock and endotoxemia produce muscle dysfunction and oxidative stress due to increased steady state concentrations of reactive oxygen and nitrogen species.

Neutral endopeptidase modulates substance P-induced activation of human neutrophils.

PubMed

Iwamoto, I; Kimura, A; Yamazaki, H; Nakagawa, N; Tomioka, H; Yoshida, S

1990-01-01

Neutral endopeptidase (NEP; EC 3.4.24.11) is well recognized as a regulatory peptidase for substance P (SP)-induced responses in various tissues. To determine whether NEP regulates SP-induced activation of human neutrophils, we examined the effect of the NEP inhibitor phosphoramidon on SP-induced superoxide generation and chemotaxis in human blood neutrophils. SP (10(-6)-10(-4) M) induced superoxide generation and chemotaxis in the neutrophils dose dependently. The NEP inhibitor enhanced the SP-induced responses. Thus, phosphoramidon (10(-6) M) shifted the dose-response curves of SP-induced superoxide generation and chemotaxis of the neutrophils to the left by 0.5-0.6 log. Phosphoramidon prevented the hydrolysis of SP by the neutrophils, the NEP activity of the neutrophils being assessed as 125 +/- 13 pmol of SP/min/10(6) cells. The N-terminal peptide SP (up to 3 x 10(-4) M), which was a major degrading product by NEP of the neutrophils, did not activate the neutrophils. We conclude that NEP modulates SP-induced activation of human neutrophils.

[Active forms of oxygen and nitrogen in blood cells of patients with rheumatoid arthritis: effect of laser therapy].

PubMed

Ostrakhovich, E A; Ilich-Stoianovich, O; Afanas'ev, I B

2001-01-01

Infrared pulse laser therapy was studied for its impact on the production of active forms of oxygen and nitrogen by neutrophils from patients with rheumatoid arthritis (RA). The authors determined the non-activated and PMA-activated production of superoxide anion-radical, peroxynitrite, peripheral neurophilic NAD.PH-oxidase and superoxide dismutase activities, and the red blood cell concentrations of reduced glutathione. Before therapy, non-activation RA neurophilic production of superoxide was much higher than in donors. Laser therapy made this parameter normal. Similarly, neutrophilic peroxynitrite production (defined by dihydrorhodamine oxidation) in RA patients was 1.7 times higher than the normal values. IF-laser therapy decreased peroxynitrite production to the values observed in donors. It is important that the therapy caused increased SOD activity (that was lower in RA patients prior to therapy) up to apparently control values. Thus, IF-laser therapy has a certain antioxidative effect by increasing SOD activity in RA patients' blood cells and reducing the production of highly reactive oxygen and nitrogen forms.

Effects of quercetin on heart nitric oxide metabolism in l-NAME treated rats.

PubMed

Calabró, Valeria; Litterio, María C; Fraga, Cesar G; Galleano, Monica; Piotrkowski, Barbara

2018-06-01

This study investigated the effects of a quercetin-supplemented diet on the biochemical changes installed in the heart of NO-deficient rats in terms of oxidants production and NO bioavailability determinants. Sprague-Dawley rats were subjected to N ω -nitro-l-arginine methyl ester (l-NAME) treatment (360 mg/L l-NAME in the drinking water, 4 d) with or without supplementation with quercetin (4 g/kg diet). l-NAME administration led to increased blood pressure (BP) (30%), decreased nitric oxide synthase (NOS) activity (50%), and increases in NADPH oxidase (NOX)-dependent superoxide anion production (60%) and p47 phox protein level (65%). The co-administration of quercetin prevented the increase in BP and the activation of NOX but did not modify the decrease in NOS activity caused by l-NAME. In addition, quercetin affected oxidative stress parameters as glutathione oxidation, and the activities of oxidant detoxifying enzymes superoxide dismutase, glutathione peroxidase, and catalase. Thus, quercetin administration counteracts l-NAME effects on NO bioavailability determinants in vivo, essentially through controlling NOX-mediated superoxide anion production. Copyright © 2018. Published by Elsevier Inc.

The Cu-Zn superoxide dismutase (SOD1) inhibits ERK phosphorylation by muscarinic receptor modulation in rat pituitary GH3 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Secondo, Agnese; De Mizio, Mariarosaria; Zirpoli, Laura

The Cu-Zn superoxide dismutase (SOD1) belongs to a family of isoenzymes that are able to dismutate the oxygen superoxide in hydrogen peroxide and molecular oxygen. This enzyme is secreted by many cellular lines and it is also released trough a calcium-dependent depolarization mechanism involving SNARE protein SNAP 25. Using rat pituitary GH3 cells that express muscarinic receptors we found that SOD1 inhibits P-ERK1/2 pathway trough an interaction with muscarinic M1 receptor. This effect is strengthened by oxotremorine, a muscarinic M agonist and partially reverted by pyrenzepine, an antagonist of M1 receptor; moreover this effect is independent from increased intracellular calciummore » concentration induced by SOD1. Finally, P-ERK1/2 inhibition was accompanied by the reduction of GH3 cell proliferation. These data indicate that SOD1 beside the well studied antioxidant properties can be considered as a neuromodulator able to affect mitogen-activated protein kinase in rat pituitary cells trough a M1 muscarinic receptor.« less

Rapid Diagnostic Device for Subclinical Mastitis Based on Electrochemical Detection of Superoxide Produced from Neutrophils in Fresh Milk

NASA Astrophysics Data System (ADS)

Okada, Kohei; Fukuda, Junji; Suzuki, Hiroaki

Electrochemical microdevices were fabricated to identify mastitic cows based on the increased number of neutrophils in raw milk. Because neutrophils produce superoxide (O2·-), the amount of O2·- can be used as an early indicator for subclinical mastitis. In the microdevices, O2·- was detected on a gold electrode using superoxide dismutase immobilized via a self-assembled monolayer of cysteine. In a preliminary test using xanthine oxidase to produce O2·-, one of the devices detected the production and rapid extinction of O2·-. When neutrophils obtained from a mastitic cow were concentrated by centrifugation and introduced into the device, a current increase distinctly different from the background was observed. Furthermore, a micropillar structure was fabricated on the gold electrode to trap and collect neutrophils, thereby facilitating the concentration of these cells around the electrode. The measured current clearly depended on the number of neutrophils in raw milk samples, demonstrating the applicability of the device for rapid diagnosis of subclinical mastitis.

Potential application of aqueous two-phase systems and three-phase partitioning for the recovery of superoxide dismutase from a clarified homogenate of Kluyveromyces marxianus.

PubMed

Simental-Martínez, Jesús; Rito-Palomares, Marco; Benavides, Jorge

2014-01-01

Superoxide dismutase (SOD; EC 1.15.1.1) is an antioxidant enzyme that represents the primary cellular defense against superoxide radicals and has interesting applications in the medical and cosmetic industries. In the present work, the partition behavior of SOD in aqueous two-phase systems (ATPS) (using a standard solution and a complex extract from Kluyveromyces marxianus as sample) was characterized on different types of ATPS (polymer-polymer, polymer-salt, alcohol-salt, and ionic liquid (IL)-salt). The systems composed of PEG 3350-potassium phosphate, 45% TLL, 0.5 M NaCl (315 U/mg, 87% recovery, and 15.1-fold purification) and t-butanol-20% ammonium sulfate (205.8 U/mg, 80% recovery and 9.8-fold purification), coupled with a subsequent 100 kDa ultrafiltration stage, allowed the design of a prototype process for the recovery and partial purification of the product of interest. The findings reported herein demonstrate the potential of PEG-salt ATPS for the potential recovery of SOD. © 2014 American Institute of Chemical Engineers.

Curcumin modulates free radical quenching in myocardial ischaemia in rats.

PubMed

Manikandan, Panchatcharam; Sumitra, Miriyala; Aishwarya, Srinivasan; Manohar, Bhakthavatsalam Murali; Lokanadam, Beema; Puvanakrishnan, Rengarajulu

2004-10-01

This study was designed to investigate the protective effect of curcumin (CUR) against isoprenaline induced myocardial ischaemia in rat myocardium. The effect of single oral dose of curcumin (15 mg kg(-1)), administered 30 min before and/or after the onset of ischaemia, was investigated by assessing oxidative stress related biochemical parameters in rat myocardium. Curcumin pre and post-treatment (PPT) was shown to decrease the levels of xanthine oxidase, superoxide anion, lipid peroxides (LPs) and myeloperoxidase while the levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) activities were significantly increased after curcumin PPT. Histopathological and transmission electron microscopical studies also confirmed the severe myocardial damage occurring as a consequence of isoprenaline induced ischaemia and they also showed the significant improvement effected by curcumin PPT. These findings provided evidence that curcumin was found to protect rat myocardium against ischaemic insult and the protective effect could be attributed to its antioxidant properties as well as its inhibitory effects on xanthine dehydrogenase/xanthine oxidase (XD/XO) conversion and resultant superoxide anion production.

(-)-Xanthienopyran, a new inhibitor of superoxide anion generation by activated neutrophils, and further constituents of the seeds of Xanthium strumarium.

PubMed

Lee, Chia-Lin; Huang, Po-Ching; Hsieh, Pei-Wen; Hwang, Tsong-Long; Hou, Yu-Yi; Chang, Fang-Rong; Wu, Yang-Chang

2008-08-01

The dried seeds of XANTHIUM STRUMARIUM (Asteraceae) are used after thorough stir-frying as an ingredient in traditional Chinese medicines for relieving allergy. Two new compounds, xanthialdehyde ( 2) and (-)-xanthienopyran ( 7), as well as 26 known compounds were isolated in the present study. The structures of the isolates were elucidated by spectroscopic methods. Among them, compound 7 exhibited significant selective inhibition of superoxide anion generation by human neutrophils induced by formyl- L-methionyl- L-leucyl- L-phenylalanine, with an IC50 value of 1.72 microg/mL.

Zymography Methods to Simultaneously Analyze Superoxide Dismutase and Catalase Activities: Novel Application for Yeast Species Identification.

PubMed

Gamero-Sandemetrio, Esther; Gómez-Pastor, Rocío; Matallana, Emilia

2017-01-01

We provide an optimized protocol for a double staining technique to analyze superoxide dismutase enzymatic isoforms Cu-Zn SOD (Sod1) and Mn-SOD (Sod2) and catalase in the same polyacrylamide gel. The use of NaCN, which specifically inhibits yeast Sod1 isoform, allows the analysis of Sod2 isoform while the use of H 2 O 2 allows the analysis of catalase. The identification of a different zymography profiling of SOD and catalase isoforms in different yeast species allowed us to propose this technique as a novel yeast identification and classification strategy.

Photochemical method for generating superoxide radicals (O.sub.2.sup.-) in aqueous solutions

DOEpatents

Holroyd, Richard A.; Bielski, Benon H. J.

1980-01-01

A photochemical method and apparatus for generating superoxide radicals (ub.2.sup.-) in an aqueous solution by means of a vacuum-ultraviolet lamp of simple design. The lamp is a microwave powered rare gas device that emits far-ultraviolet light. The lamp includes an inner loop of high purity quartz tubing through which flows an oxygen-saturated sodium formate solution. The inner loop is designed so that the solution is subjected to an intense flux of far-ultraviolet light. This causes the solution to photodecompose and form the product radical (O.sub.2.sup.-).

Glutarimide alkaloids and a terpenoid benzoquinone from Cordia globifera.

PubMed

Parks, Joshua; Gyeltshen, Thinley; Prachyawarakorn, Vilailak; Mahidol, Chulabhorn; Ruchirawat, Somsak; Kittakoop, Prasat

2010-05-28

Three new compounds, a meroterpene (2) having a cyclopropane moiety named globiferane and glutarimide alkaloids named cordiarimides A (3) and B (4), were isolated from the roots of Cordia globifera. Compounds 2-4 exhibited weak cytotoxic activity. Cordiarimide B (4) exhibited radical scavenging activity, as it inhibited superoxide anion radical formation in the xanthine/xanthine oxidase (XXO) assay, and also suppressed superoxide anion generation in differentiated HL-60 human promyelocytic leukemia cells when induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). This is the first report on the presence of glutarimide alkaloids in the genus Cordia.

Efficacy of peptide nucleic acid and selected conjugates against specific cellular pathologies of amyotrophic lateral sclerosis.

PubMed

Browne, Elisse C; Parakh, Sonam; Duncan, Luke F; Langford, Steven J; Atkin, Julie D; Abbott, Belinda M

2016-04-01

Cellular studies have been undertaken on a nonamer peptide nucleic acid (PNA) sequence, which binds to mRNA encoding superoxide dismutase 1, and a series of peptide nucleic acids conjugated to synthetic lipophilic vitamin analogs including a recently prepared menadione (vitamin K) analog. Reduction of both mutant superoxide dismutase 1 inclusion formation and endoplasmic reticulum stress, two of the key cellular pathological hallmarks in amyotrophic lateral sclerosis, by two of the prepared PNA oligomers is reported for the first time. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Recycling ferrous sulfate via super-oxidant synthesis

NASA Astrophysics Data System (ADS)

Kanari, N.; Evrard, O.; Neveux, N.; Ninane, L.

2001-11-01

Hydrated ferrous sulfate, a by-product of the titanium-dioxide and steel-surface-treatment industries, is usually disposed of as waste at a significant extra cost for these industries. Due to tight environmental regulations in the European countries, waste disposal of ferrous sulfate will not be an acceptable solution in the near future. Consequently, the waste will have to be treated. Recently, ferrous sulfate was successfully used to synthesize a novel superoxidant material (potassium ferrate) containing iron in hexavalent state (FeVI). With ferrates synthesis, innovative applications are possible in different industrial sectors, such as treatment of water and wastewater and effluent decontamination.

Conjugates of Superoxide Dismutase 1 with Amphiphilic Poly(2-oxazoline) Block Copolymers for Enhanced Brain Delivery: Synthesis, Characterization and Evaluation in vitro and in vivo

PubMed Central

Tong, Jing; Yi, Xiang; Luxenhofer, Robert; Banks, William A.; Jordan, Rainer; Zimmerman, Matthew C.; Kabanov, Alexander V.

2013-01-01

Superoxide dismutase 1 (SOD1) efficiently catalyzes dismutation of superoxide but its poor delivery to the target sites in the body, such as brain, hinders its use as a therapeutic agent for superoxide-associated disorders. Here to enhance the delivery of SOD1 across the blood brain barrier (BBB) and in neurons the enzyme was conjugated with poly(2-oxazoline) (POx) block copolymers, P(MeOx-b-BuOx) or P(EtOx-b-BuOx), comprised of 1) hydrophilic 2-methyl-2-oxazoline (MeOx) or 2-ethyl-2-oxazoline (EtOx) and 2) hydrophobic 2-butyl-2-oxazoline (BuOx) repeating units. The conjugates contained from 2 to 3 POx chains joining the protein amino groups via cleavable -(ss)- or non-cleavable –(cc)- linkers at the BuOx block terminus. They retained 30% to 50% of initial SOD1 activity, were conformationally and thermally stable and assembled in 8 or 20 nm aggregates in aqueous solution. They had little if any toxicity to CATH.a neurons and displayed enhanced uptake in these neurons as compared to native or PEGylated SOD1. Of the two conjugates, SOD1-(cc)-P(MeOx-b-BuOx) and SOD1-(cc)-P(EtOx-b-BuOx) compared, the latter was entering cells 4 to 7 times faster and at 6 h colocalized predominantly with endoplasmic reticulum (41 ± 3%) and mitochondria (21 ± 2%). Colocalization with endocytosis markers and pathway inhibition assays suggested that it was internalized through lipid raft/caveolae, also employed by the P(EtOx-b-BuOx) copolymer. The SOD activity in cell lysates and ability to attenuate angiotensin II (Ang II)-induced superoxide in live cells were increased for this conjugate compared to SOD1 and PEG-SOD1. Studies in mice showed that SOD1-POx had ca. 1.75 times longer half-life in blood than native SOD1 (28.4 vs 15.9 min) and after i.v. administration penetrated the BBB significantly faster than albumin to accumulate in brain parenchyma. The conjugate maintained high stability both in serum and in brain (77% vs. 84% at 1 h post injection). Its amount taken up by the brain reached a maximum value of 0.08%ID/g (percent of the injected dose taken up per gram of brain) 4 h post injection. The entry of SOD1-(cc)-P(EtOx-b-BuOx) to the brain was mediated by a non-saturable mechanism. Altogether, SOD1-POx conjugates are promising candidates as macromolecular antioxidant therapies for superoxide-associated diseases such as Ang II induced neuro-cardiovascular diseases. PMID:23163230

Markers for vulnerability in acute porphyria. A hypothesis paper.

PubMed

Thunell, S; Andersson, C; Carlmark, B; Floderus, Y; Grönqvist, S O; Harper, P; Henrichson, A; Lindh, U

1995-04-01

Previously symptomatic and permanently asymptomatic carriers of a gene mutation for acute intermittent porphyria as well as matched controls were screened with regard to a series of variables of possible relevance to the development of porphyric symptoms. The basis for the study was a concept of acute porphyria as a condition of a permanent system overload of oxidative stress, with long term effects on hepatic and renal tissue, and with instances of periodic overload of free radicals giving rise to acute neurologic involvement. Leukocyte concentrations of manganese, calcium, iron and zinc, as well as erythrocyte calcium differed between the groups, acute intermittent porphyria gene carriers, irrespective of previous porphyric illness, showing significantly higher levels than the controls. Manganese was found to be the most discriminative component of all the 78 variables investigated, accounting for about 98 per cent of the variance between the groups. An increment, by a factor of four, in cellular manganese is suggestive of an increase, in acute intermittent porphyria, of a manganese associated enzyme, e.g. glutamine synthetase, pyruvate carboxylase or mitochondrial superoxide dismutase. The best fit into the model considered is provided by a theory focused on superoxide dismutase, induced in response to superoxide anion radical produced from aminolaevulinic acid. In porphyria gene carriers seemingly resistant to porphyric manifestations, an increase in potentially prooxidant cellular iron is matched by a proportional increment in manganese, i.e. presumably by a corresponding mitochondrial superoxide dismutase induction. This mechanism is not operative in porphyric individuals prone to development of neuropsychiatric symptoms. In acute intermittent porphyria with a history of porphyric illness there is a positive correlation between erythrocyte manganese and serum folate and a negative correlation between leukocyte ferrochelatase activity and serum cobalamin concentration. This may mirror a role of the cobalamin-folate system in the acute porphyric process.

Bioaccumulation and biodegradation of sulfamethazine in Chlorella pyrenoidosa

NASA Astrophysics Data System (ADS)

Sun, Ming; Lin, Hong; Guo, Wen; Zhao, Fazhen; Li, Jian

2017-12-01

Intensive use of sulfamethazine (SM2) in aquaculture has resulted in some detrimental effects to non-targeted organisms. In order to assess its potential ecological risk, it is crucial to have a good understanding on the bioaccumulation and biodegradation of SM2 in Chlorella pyrenoidosa. The microalgae were treated with 2, 4, and 8 mg L-1 of sulfamethazine for 13 days, respectively, showing that the inhibition effects of sulfamethazine on the growth of Chlorella pyrenoidosa increased progressively as the concentrations of sulfamethazine increasing from 2 to 8 mg L-1. The peak concentrations of sulfamethazine accumulated in C. pyrenoidosa were 0.225, 0.325, and 0.596 ng per mg FW on day 13 for three treatment groups, respectively, showing a great ability to deplete sulfamethazine from the culture media. On day 13, the percentages of biotic degradation were 48.45%, 60.21% and 69.93%, respectively. The EC50 of 10.05 mg L-1 was derived which showed no significant risk for C. pyrenoidosa with a calculated risk quotient < 1. The activities of superoxide dismutase and catalase increased progressively in response to sulfamethazine and showed a positive correlation to the treatment concentrations. The highest superoxide dismutase activity was achieved at the concentration of 8 mg L-1 after 2 d of exposure, which was 1.89 folds higher than that of the control. The activity of catalase has a similar pattern to that of superoxide dismutase with the maximum activity achieved at day 2, which was 3.11 folds higher compared to that of the control. In contrast to superoxide dismutase and catalase, the maximum glutathione S-transferase activity was observed at day 6, showing 2.2 folds higher than that of the control.

The Phylogeny and Active Site Design of Eukaryotic Copper-only Superoxide Dismutases*

PubMed Central

Peterson, Ryan L.; Galaleldeen, Ahmad; Villarreal, Johanna; Taylor, Alexander B.; Cabelli, Diane E.; Hart, P. John; Culotta, Valeria C.

2016-01-01

In eukaryotes the bimetallic Cu/Zn superoxide dismutase (SOD) enzymes play important roles in the biology of reactive oxygen species by disproportionating superoxide anion. Recently, we reported that the fungal pathogen Candida albicans expresses a novel copper-only SOD, known as SOD5, that lacks the zinc cofactor and electrostatic loop (ESL) domain of Cu/Zn-SODs for substrate guidance. Despite these abnormalities, C. albicans SOD5 can disproportionate superoxide at rates limited only by diffusion. Here we demonstrate that this curious copper-only SOD occurs throughout the fungal kingdom as well as in phylogenetically distant oomycetes or “pseudofungi” species. It is the only form of extracellular SOD in fungi and oomycetes, in stark contrast to the extracellular Cu/Zn-SODs of plants and animals. Through structural biology and biochemical approaches we demonstrate that these copper-only SODs have evolved with a specialized active site consisting of two highly conserved residues equivalent to SOD5 Glu-110 and Asp-113. The equivalent positions are zinc binding ligands in Cu/Zn-SODs and have evolved in copper-only SODs to control catalysis and copper binding in lieu of zinc and the ESL. Similar to the zinc ion in Cu/Zn-SODs, SOD5 Glu-110 helps orient a key copper-coordinating histidine and extends the pH range of enzyme catalysis. SOD5 Asp-113 connects to the active site in a manner similar to that of the ESL in Cu/Zn-SODs and assists in copper cofactor binding. Copper-only SODs are virulence factors for certain fungal pathogens; thus this unique active site may be a target for future anti-fungal strategies. PMID:27535222

Extracellular Superoxide Dismutase Deficiency Exacerbates Pressure Overload–Induced Left Ventricular Hypertrophy and Dysfunction

PubMed Central

Lu, Zhongbing; Xu, Xin; Hu, Xinli; Zhu, Guangshuo; Zhang, Ping; van Deel, Elza D.; French, Joel P.; Fassett, John T.; Oury, Tim D.; Bache, Robert J.; Chen, Yingjie

2008-01-01

Extracellular superoxide dismutase (SOD) contributes only a small fraction to total SOD activity in the normal heart but is strategically located to scavenge free radicals in the extracellular compartment. To examine the physiological significance of extracellular SOD in the response of the heart to hemodynamic stress, we studied the effect of extracellular SOD deficiency on transverse aortic constriction (TAC)–induced left ventricular remodeling. Under unstressed conditions extracellular SOD deficiency had no effect on myocardial total SOD activity, the ratio of glutathione:glutathione disulfide, nitrotyrosine content, or superoxide anion production but resulted in small but significant increases in myocardial fibrosis and ventricular mass. In response to TAC for 6 weeks, extracellular SOD-deficient mice developed more severe left ventricular hypertrophy (heart weight increased 2.56-fold in extracellular SOD-deficient mice as compared with 1.99-fold in wild-type mice) and pulmonary congestion (lung weight increased 2.92-fold in extracellular SOD-deficient mice as compared with 1.84-fold in wild-type mice). Extracellular SOD-deficient mice also had more ventricular fibrosis, dilation, and a greater reduction of left ventricular fractional shortening and rate of pressure development after TAC. TAC resulted in greater increases of ventricular collagen I, collagen III, matrix metalloproteinase-2, matrix metalloproteinase-9, nitrotyrosine, and superoxide anion production. TAC also resulted in a greater decrease of the ratio of glutathione:glutathione disulfide in extracellular SOD-deficient mice. The finding that extracellular SOD deficiency had minimal impact on myocardial overall SOD activity but exacerbated TAC induced myocardial oxidative stress, hypertrophy, fibrosis, and dysfunction indicates that the distribution of extracellular SOD in the extracellular space is critically important in protecting the heart against pressure overload. PMID:17998475

Sitagliptin attenuates sympathetic innervation via modulating reactive oxygen species and interstitial adenosine in infarcted rat hearts.

PubMed

Lee, Tsung-Ming; Chen, Wei-Ting; Yang, Chen-Chia; Lin, Shinn-Zong; Chang, Nen-Chung

2015-02-01

We investigated whether sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, attenuates arrhythmias through inhibiting nerve growth factor (NGF) expression in post-infarcted normoglycemic rats, focusing on adenosine and reactive oxygen species production. DPP-4 bound adenosine deaminase has been shown to catalyse extracellular adenosine to inosine. DPP-4 inhibitors increased adenosine levels by inhibiting the complex formation. Normoglycemic male Wistar rats were subjected to coronary ligation and then randomized to either saline or sitagliptin in in vivo and ex vivo studies. Post-infarction was associated with increased oxidative stress, as measured by myocardial superoxide, nitrotyrosine and dihydroethidium fluorescent staining. Measurement of myocardial norepinephrine levels revealed a significant elevation in vehicle-treated infarcted rats compared with sham. Compared with vehicle, infarcted rats treated with sitagliptin significantly increased interstitial adenosine levels and attenuated oxidative stress. Sympathetic hyperinnervation was blunted after administering sitagliptin, as assessed by immunofluorescent analysis and western blotting and real-time quantitative RT-PCR of NGF. Arrhythmic scores in the sitagliptin-treated infarcted rats were significantly lower than those in vehicle. Ex vivo studies showed a similar effect of erythro-9-(2-hydroxy-3-nonyl) adenine (an adenosine deaminase inhibitor) to sitagliptin on attenuated levels of superoxide and NGF. Furthermore, the beneficial effects of sitagliptin on superoxide anion production and NGF levels can be reversed by 8-cyclopentyl-1,3-dipropulxanthine (adenosine A1 receptor antagonist) and exogenous hypoxanthine. Sitagliptin protects ventricular arrhythmias by attenuating sympathetic innervation via adenosine A1 receptor and xanthine oxidase-dependent pathways, which converge through the attenuated formation of superoxide in the non-diabetic infarcted rats. © 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.

EFFECTS AND MECHANISMS OF A NEW MULTIVITAMIN ON CHRONIC METABOLIC SYNDROMES AND AGING

PubMed Central

Wu, Su-xi; Jiang, Xuewei; Liu, Yu-ying; Chen, Lin-feng; Tao, Jun

2017-01-01

Background: Increased occurrence of chronic syndromes has prompted researchers to investigate and develop drugs and methods for controlling chronic syndromes with a view to improve human health and reduce early aging. Material and methods: Human trials: After the allotted multivitamin pills or placebo pills had been taken for a stipulated period of about 2 months, the volunteers filled out feedback forms on curative effects of the pills in line with the health examination reports. The effects of the multivitamin on various symptoms or diseases and dysfunctions of the chronic metabolic syndromes were noted and evaluated based on the information provided in forms. Animal experiments: Mouse aging model induced by D-galactose were administered the multivitamin by oral gavage every morning. At the end of the sixth week, activity or content of the components associated with ageing and anti-aging in the brain and liver of the aging mice were determined to investigate the mechanisms of the new multivitamin on chronic metabolic syndromes and aging. Results: We found that multivitamin can eliminate or attenuate 38 types of symptoms or dysfunctions of the investigated metabolic syndromes; and that it has both preventive and curative/adjunctive therapeutic effects on the metabolic syndromes. The effects of this multivitamin on components associated with aging and anti-aging were significantly decreased - malondialdehyde content and monoamine oxidase activity but significantly increased activity of superoxide dismutase and glutathione peroxidase. This multivitamin has significant anti-aging effects. Conclusion: Supplementing with this multivitamin can prevent and provide treatment/adjunctive therapy for these chronic metabolic syndromes and delay the aging process. List of Abbreviations BW body weight; Cu/Zn-SOD, cuprum/zinc-superoxide dismutase MAO monoamine oxidase MDA malondialdehyde; Mn-SOD, manganese-superoxide dismutase; T-SOD, total superoxide dismutase; TP, total protein PMID:28331914

The Phylogeny and Active Site Design of Eukaryotic Copper-only Superoxide Dismutases

DOE PAGES

Peterson, Ryan L.; Galaleldeen, Ahmad; Villarreal, Johanna; ...

2016-08-17

In eukaryotes the bimetallic Cu/Zn superoxide dismutase (SOD) enzymes play important roles in the biology of reactive oxygen species by disproportionating superoxide anion. We reported that the fungal pathogen Candida albicans expresses a novel copper-only SOD, known as SOD5, that lacks the zinc cofactor and electrostatic loop (ESL) domain of Cu/Zn-SODs for substrate guidance. In spite of these abnormalities, C. albicans SOD5 can disproportionate superoxide at rates limited only by diffusion. Here we demonstrate that this curious copper-only SOD occurs throughout the fungal kingdom as well as in phylogenetically distant oomycetes or “pseudofungi” species. It is the only form ofmore » extracellular SOD in fungi and oomycetes, in stark contrast to the extracellular Cu/Zn-SODs of plants and animals. Through structural biology and biochemical approaches we demonstrate that these copper-only SODs have evolved with a specialized active site consisting of two highly conserved residues equivalent to SOD5 Glu-110 and Asp-113. The equivalent positions are zinc binding ligands in Cu/Zn-SODs and have evolved in copper-only SODs to control catalysis and copper binding in lieu of zinc and the ESL. Similar to the zinc ion in Cu/Zn-SODs, SOD5 Glu-110 helps orient a key copper-coordinating histidine and extends the pH range of enzyme catalysis. Furthermore, SOD5 Asp-113 connects to the active site in a manner similar to that of the ESL in Cu/Zn-SODs and assists in copper cofactor binding. Copper-only SODs are virulence factors for certain fungal pathogens; thus this unique active site may be a target for future anti-fungal strategies.« less

Zinc-Dependent Protection of Tobacco and Rice Cells From Aluminum-Induced Superoxide-Mediated Cytotoxicity

PubMed Central

Lin, Cun; Hara, Ayaka; Comparini, Diego; Bouteau, François; Kawano, Tomonori

2015-01-01

Al3+ toxicity in growing plants is considered as one of the major factors limiting the production of crops on acidic soils worldwide. In the last 15 years, it has been proposed that Al3+ toxicity are mediated with distortion of the cellular signaling mechanisms such as calcium signaling pathways, and production of cytotoxic reactive oxygen species (ROS) causing oxidative damages. On the other hand, zinc is normally present in plants at high concentrations and its deficiency is one of the most widespread micronutrient deficiencies in plants. Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells. Previously, inhibitory action of Zn2+ against lanthanide-induced superoxide generation in tobacco cells have been reported, suggesting that Zn2+ interferes with the cation-induced ROS production via stimulation of NADPH oxidase. In the present study, the effect of Zn2+ on Al3+-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv. Nipponbare), was examined. The Zn2+-dependent inhibition of the Al3+-induced oxidative burst was observed in both model cells selected from the monocots and dicots (rice and tobacco), suggesting that this phenomenon (Al3+/Zn2+ interaction) can be preserved in higher plants. Subsequently induced cell death in tobacco cells was analyzed by lethal cell staining with Evans blue. Obtained results indicated that presence of Zn2+ at physiological concentrations can protect the cells by preventing the Al3+-induced superoxide generation and cell death. Furthermore, the regulation of the Ca2+ signaling, i.e., change in the cytosolic Ca2+ ion concentration, and the cross-talks among the elements which participate in the pathway were further explored. PMID:26648960

Adenosine 3′,5′-cyclic monophosphate (cAMP)-dependent phosphoregulation of mitochondrial complex I is inhibited by nucleoside reverse transcriptase inhibitors

PubMed Central

Lund, Kaleb C.; Wallace, Kendall B.

2008-01-01

Nucleoside analog reverse transcriptase inhibitors (NRTI) are known to directly inhibit mitochondrial complex I activity as well as various mitochondrial kinases. Recent observations that complex I activity and superoxide production are modulated through cAMP-dependent phosphorylation suggests a mechanism through which NRTIs may affect mitochondrial respiration via kinase-dependent protein phosphorylation. In the current study we examine the potential for NRTIs to inhibit the cAMP-dependent phosphorylation of complex I and the associated NADH:CoQ oxidoreductase activities and rates of superoxide production using HepG2 cells. Phosphoprotein staining of immunocaptured complex I revealed that 3′-azido-3′-deoxythymidine (AZT; 10 and 50 μM), AZT monophosphate (150 μM), and 2′,3′-dideoxycytidine (ddC; 1μM) prevented the phosphorylation of the NDUFB11 subunit of complex I. This was associated with a decrease in complex I activity with AZT and AZT monophosphate only. In the presence of succinate, superoxide production was increased with 2′,3′-dideoxyinosine (ddI; 10 μM) and ddC (1 μM). In the presence of succinate + cAMP AZT showed an inverse dose-dependent effect on superoxide production. None of the NRTIs examined inhibit PKA activity suggesting that the observed effects are due to a direct interaction with complex I. These data demonstrate a direct effect of NRTIs on cAMP-dependent regulation of mitochondrial bioenergetics independent of DNA polymerase-γ activity; in the case of AZT these observations may provide a mechanism for the observed long-term toxicity with this drug. PMID:17904600

EFFECTS AND MECHANISMS OF A NEW MULTIVITAMIN ON CHRONIC METABOLIC SYNDROMES AND AGING.

PubMed

Wu, Su-Xi; Jiang, Xuewei; Liu, Yu-Ying; Chen, Lin-Feng; Tao, Jun

2017-01-01

Increased occurrence of chronic syndromes has prompted researchers to investigate and develop drugs and methods for controlling chronic syndromes with a view to improve human health and reduce early aging. Human trials: After the allotted multivitamin pills or placebo pills had been taken for a stipulated period of about 2 months, the volunteers filled out feedback forms on curative effects of the pills in line with the health examination reports. The effects of the multivitamin on various symptoms or diseases and dysfunctions of the chronic metabolic syndromes were noted and evaluated based on the information provided in forms. Animal experiments: Mouse aging model induced by D-galactose were administered the multivitamin by oral gavage every morning. At the end of the sixth week, activity or content of the components associated with ageing and anti-aging in the brain and liver of the aging mice were determined to investigate the mechanisms of the new multivitamin on chronic metabolic syndromes and aging. We found that multivitamin can eliminate or attenuate 38 types of symptoms or dysfunctions of the investigated metabolic syndromes; and that it has both preventive and curative/adjunctive therapeutic effects on the metabolic syndromes. The effects of this multivitamin on components associated with aging and anti-aging were significantly decreased - malondialdehyde content and monoamine oxidase activity but significantly increased activity of superoxide dismutase and glutathione peroxidase. This multivitamin has significant anti-aging effects. Supplementing with this multivitamin can prevent and provide treatment/adjunctive therapy for these chronic metabolic syndromes and delay the aging process. List of AbbreviationsBWbody weight; Cu/Zn-SOD, cuprum/zinc-superoxide dismutaseMAOmonoamine oxidaseMDAmalondialdehyde; Mn-SOD, manganese-superoxide dismutase; T-SOD, total superoxide dismutase; TP, total protein.

Revealing mechanisms of selective, concentration-dependent potentials of 4-hydroxy-2-nonenal to induce apoptosis in cancer cells through inactivation of membrane-associated catalase.

PubMed

Bauer, Georg; Zarkovic, Neven

2015-04-01

Tumor cells generate extracellular superoxide anions and are protected against superoxide anion-mediated intercellular apoptosis-inducing signaling by the expression of membrane-associated catalase. 4-Hydroxy-2-nonenal (4-HNE), a versatile second messenger generated during lipid peroxidation, has been shown to induce apoptosis selectively in malignant cells. The findings described in this paper reveal the strong, concentration-dependent potential of 4-HNE to specifically inactivate extracellular catalase of tumor cells both indirectly and directly and to consequently trigger apoptosis in malignant cells through superoxide anion-mediated intercellular apoptosis-inducing signaling. Namely, 4-HNE caused apoptosis selectively in NOX1-expressing tumor cells through inactivation of their membrane-associated catalase, thus reactivating subsequent intercellular signaling through the NO/peroxynitrite and HOCl pathways, followed by the mitochondrial pathway of apoptosis. Concentrations of 4-HNE of 1.2 µM and higher directly inactivated membrane-associated catalase of tumor cells, whereas at lower concentrations, 4-HNE triggered a complex amplificatory pathway based on initial singlet oxygen formation through H2O2 and peroxynitrite interaction. Singlet-oxygen-dependent activation of the FAS receptor and caspase-8 increased superoxide anion generation by NOX1 and amplification of singlet oxygen generation, which allowed singlet-oxygen-dependent inactivation of catalase. 4-HNE and singlet oxygen cooperate in complex autoamplificatory loops during this process. The finding of these novel anticancer pathways may be useful for understanding the role of 4-HNE in the control of malignant cells and for the optimization of ROS-dependent therapeutic approaches including antioxidant treatments. Copyright © 2015 Elsevier Inc. All rights reserved.

γ-Secretase Inhibition of Murine Choroidal Neovascularization Is Associated with Reduction of Superoxide and Proinflammatory Cytokines

PubMed Central

Qi, Xiaoping; Cai, Jun; Ruan, Qing; Liu, Li; Boye, Sanford L.; Chen, Zhijuan; Hauswirth, William W.; Ryals, Renee C.; Shaw, Lynn; Caballero, Sergio; Grant, Maria B.

2012-01-01

Purpose. This study aimed to determine whether upregulation of γ-secretase could inhibit laser-induced choroidal neovascularization (CNV) and if this was associated with a reduction in both oxidative stress and proinflammatory cytokines. Methods. γ-Secretase, or its catalytic subunit presenilin 1 (PS1), were upregulated by exposure to either pigment epithelial derived factor (PEDF) or an AAV2 vector containing a PS1 gene driven by a vascular endothelial-cadherin promoter. Retinal endothelial cells were infected with AAV2 or exposed to PEDF in the presence or absence of VEGF and in vitro angiogenesis determined. Mouse eyes either received intravitreal injection of PEDF, DAPT (a γ-secretase inhibitor) or PEDF + DAPT at the time of laser injury, or AAV2 infection 3 weeks before receiving laser burns. Lesion volume was determined 14 days post laser injury. Superoxide generation, antioxidant activity and the production of proinflammatory mediators were assessed. Knockdown of γ-secretase was achieved using siRNA. Results. γ-Secretase upregulation and PS1 overexpression suppressed VEGF-induced in vitro angiogenesis and in vivo laser-induced CNV. This was associated with a reduction in the expression of VEGF and angiogenin 1 together with reduced superoxide anion generation and an increase in MnSOD compared with untreated CNV eyes. PS1 overexpression reduced proinflammatory factors and microglial activation in eyes with CNV compared with control. siRNA inhibition of γ-secretase resulted in increased angiogenesis. Conclusions. γ-Secretase, and in particular PS1 alone, are potent regulators of angiogenesis and this is due in part to stabilizing endogenous superoxide generation and reducing proinflammatory cytokine expression during CNV. PMID:22205609

Iron Hydroperoxide Intermediate in Superoxide Reductase: Protonation or Dissociation First? MM Dynamics and QM/MM Metadynamics Study.

PubMed

David, Rolf; Jamet, Hélène; Nivière, Vincent; Moreau, Yohann; Milet, Anne

2017-06-13

Superoxide reductase is a mononuclear iron enzyme involved in superoxide radical detoxification in some bacteria. Its catalytic mechanism is associated with the remarkable formation of a ferric hydroperoxide Fe 3+ -OOH intermediate, which is specifically protonated on its proximal oxygen to generate the reaction product H 2 O 2 . Here, we present a computational study of the protonation mechanism of the Fe 3+ -OOH intermediate, at different levels of theory. This was performed on the whole system (solvated protein) using well-tempered metadynamics at the QM/MM (B3LYP/AmberFF99SB) level. Enabled by the development of a new set of force field parameters for the active site, a conformational MM study of the Fe 3+ -OOH species gave insights into its solvation pattern, in addition to generating the two starting conformations for the ab initio metadynamics setup. Two different protonation mechanisms for the Fe 3+ -OOH intermediate have been found depending on the starting structure. Whereas a possible mechanism involves at first the protonation of the hydroperoxide ligand and then dissociation of H 2 O 2 , the most probable one starts with an unexpected dissociation of the HOO - ligand from the iron, followed by its protonation. This favored reactivity was specifically linked to the influence of both the nearby conserved lysine 48 residue and the microsolvatation on the charge distribution of the oxygens of the HOO - ligand. These data highlight the crucial role of the whole environment, solvent, and protein, to describe accurately this second protonation step in superoxide reductase. This is clearly not possible with smaller models unable to reproduce correctly the mechanistically determinant charge distribution.

Six-coordinate manganese(3+) in catalysis by yeast manganese superoxide dismutase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sheng, Yuewei; Gralla, Edith Butler; Schumacher, Mikhail

Reduction of superoxide (O{sub 2}{sup -}) by manganese-containing superoxide dismutase occurs through either a 'prompt protonation' pathway, or an 'inner-sphere' pathway, with the latter leading to formation of an observable Mn-peroxo complex. We recently reported that wild-type (WT) manganese superoxide dismutases (MnSODs) from Saccharomyces cerevisiae and Candida albicans are more gated toward the 'prompt protonation' pathway than human and bacterial MnSODs and suggested that this could result from small structural changes in the second coordination sphere of manganese. We report here that substitution of a second-sphere residue, Tyr34, by phenylalanine (Y34F) causes the MnSOD from S. cerevisiae to react exclusivelymore » through the 'inner-sphere' pathway. At neutral pH, we have a surprising observation that protonation of the Mn-peroxo complex in the mutant yeast enzyme occurs through a fast pathway, leading to a putative six-coordinate Mn3+ species, which actively oxidizes O{sub 2}{sup -} in the catalytic cycle. Upon increasing pH, the fast pathway is gradually replaced by a slow proton-transfer pathway, leading to the well-characterized five-coordinate Mn{sup 3+}. We here propose and compare two hypothetical mechanisms for the mutant yeast enzyme, diffeeing in the structure of the Mn-peroxo complex yet both involving formation of the active six-coordinate Mn{sup 3+} and proton transfer from a second-sphere water molecule, which has substituted for the -OH of Tyr34, to the Mn-peroxo complex. Because WT and the mutant yeast MnSOD both rest in the 2+ state and become six-coordinate when oxidized up from Mn{sup 2+}, six-coordinate Mn{sup 3+} species could also actively function in the mechanism of WT yeast MnSODs.« less

Chlorine gas exposure disrupts nitric oxide homeostasis in the pulmonary vasculature

PubMed Central

Honavar, Jaideep; Bradley, Eddie; Bradley, Kelley; Oh, Joo Yeun; Vallejo, Matthew O.; Kelley, Eric E.; Cantu-Medellin, Nadiezhda; Doran, Stephen; Dell’italia, Louis J.; Matalon, Sadis; Patel, Rakesh P.

2014-01-01

Exposure to chlorine (Cl2) gas during industrial accidents or chemical warfare leads to significant airway and distal lung epithelial injury that continues post exposure. While lung epithelial injury is prevalent, relatively little is known about whether Cl2 gas also promotes injury to the pulmonary vasculature. To determine this, rats were subjected to a sub-lethal Cl2 gas exposure (400ppm, 30min) and then brought back to room air. Pulmonary arteries (PA) were isolated from rats at various times post-exposure and contractile (phenylephrine) and nitric oxide (NO)-dependent vasodilation (acetylcholine and mahmanonoate) responses measured ex-vivo. PA contractility did not change, however significant inhibition of NO-dependent vasodilation was observed that was maximal at 24–48 hours post exposure. Superoxide dismutase restored NO-dependent vasodilation suggesting a role for increased superoxide formation. This was supported by ~2-fold increase in superoxide formation (measured using 2-hydroethidine oxidation to 2-OH-E+) from PA isolated from Cl2 exposed rats. We next measured PA pressures in anesthetized rats. Surprisingly, PA pressures were significantly (~4mmHg) lower in rats that had been exposed to Cl2 gas 24 hours earlier suggesting that deficit in NO-signaling observed in isolated PA experiments did not manifest as increased PA pressures in vivo. Administration of the iNOS selective inhibitor 1400W, restored PA pressures to normal in Cl2 exposed, but not control rats suggesting that any deficit in NO-signaling due to increased superoxide formation in the PA, is offset by increased NO-formation from iNOS. These data indicate that disruption of endogenous NO-signaling mechanisms that maintain PA tone is an important aspect of post-Cl2 gas exposure toxicity. PMID:24769334

Superoxide scavenging effects of N-acetylcysteine and vitamin C in subjects with essential hypertension.

PubMed

Schneider, Markus P; Delles, Christian; Schmidt, Bernhard M W; Oehmer, Sebastian; Schwarz, Thomas K; Schmieder, Roland E; John, Stefan

2005-08-01

It is not known whether the beneficial effects of N-acetylcysteine (NAC) in conditions associated with increased oxidative stress are caused by direct superoxide scavenging. We therefore compared the acute superoxide scavenging efficacy of NAC against vitamin C (VITC) on impaired endothelium-dependent vasodilation in subjects with essential hypertension. In a cross-over randomized study, the effects of intra-arterial administration of either NAC (48 mg/min) or VITC (18 mg/min) were examined in 15 subjects with essential hypertension and in 15 normotensive control subjects. Both endothelium-dependent and endothelium-independent vasodilation were determined as forearm blood flow (FBF) response to the intra-arterial administration of acetylcholine (Ach) and sodium nitroprusside (NP) in doses of 12 and 48 mug/min and 3.2 and 12.8 mug/min, respectively. Subjects with essential hypertension had impaired responses to both doses of Ach (Delta% FBF to higher dose of Ach: 325 +/- 146 in subjects with essential hypertension v 540 +/- 199 in control subjects; P = .02) and an impaired response to the higher dose of NP (330 +/- 108 v 500 +/- 199; P = .03). The intra-arterial administration of NAC had no effect on these responses (higher dose of Ach: 325 +/- 146 without v 338 +/- 112 with NAC, NS). In contrast, intra-arterial VITC improved both the response to Ach (320 +/- 132 without v 400 +/- 185 with VITC, P = .05) and to NP (383 +/- 162 v 447 +/- 170, P = .05). We found that NAC showed no statistically significant effect on either endothelium-dependent or endothelium-independent vasodilation in hypertensive subjects, whereas VITC did. We conclude that NAC is therefore not an effective superoxide scavenger in vivo. Other, nonimmediate effects such as the generation of glutathione may explain the beneficial effects of NAC in conditions associated with oxidative stress.

A lithium-oxygen battery based on lithium superoxide.

PubMed

Lu, Jun; Lee, Yun Jung; Luo, Xiangyi; Lau, Kah Chun; Asadi, Mohammad; Wang, Hsien-Hau; Brombosz, Scott; Wen, Jianguo; Zhai, Dengyun; Chen, Zonghai; Miller, Dean J; Jeong, Yo Sub; Park, Jin-Bum; Fang, Zhigang Zak; Kumar, Bijandra; Salehi-Khojin, Amin; Sun, Yang-Kook; Curtiss, Larry A; Amine, Khalil

2016-01-21

Batteries based on sodium superoxide and on potassium superoxide have recently been reported. However, there have been no reports of a battery based on lithium superoxide (LiO2), despite much research into the lithium-oxygen (Li-O2) battery because of its potential high energy density. Several studies of Li-O2 batteries have found evidence of LiO2 being formed as one component of the discharge product along with lithium peroxide (Li2O2). In addition, theoretical calculations have indicated that some forms of LiO2 may have a long lifetime. These studies also suggest that it might be possible to form LiO2 alone for use in a battery. However, solid LiO2 has been difficult to synthesize in pure form because it is thermodynamically unstable with respect to disproportionation, giving Li2O2 (refs 19, 20). Here we show that crystalline LiO2 can be stabilized in a Li-O2 battery by using a suitable graphene-based cathode. Various characterization techniques reveal no evidence for the presence of Li2O2. A novel templating growth mechanism involving the use of iridium nanoparticles on the cathode surface may be responsible for the growth of crystalline LiO2. Our results demonstrate that the LiO2 formed in the Li-O2 battery is stable enough for the battery to be repeatedly charged and discharged with a very low charge potential (about 3.2 volts). We anticipate that this discovery will lead to methods of synthesizing and stabilizing LiO2, which could open the way to high-energy-density batteries based on LiO2 as well as to other possible uses of this compound, such as oxygen storage.

Oxidative stress and APO E polymorphisms in Alzheimer's disease and in mild cognitive impairment.

PubMed

Chico, L; Simoncini, C; Lo Gerfo, A; Rocchi, A; Petrozzi, L; Carlesi, C; Volpi, L; Tognoni, G; Siciliano, G; Bonuccelli, U

2013-08-01

A number of evidences indicates oxidative stress as a relevant pathogenic factor in Alzheimer's disease (AD) and mild cognitive impairment (MCI). Considering its recognized major genetic risk factors in AD, apolipoprotein (APO E) has been investigated in several experimental settings regarding its role in the process of reactive oxygen species (ROS) generation. The aim of this work has been to evaluate possible relationships between APO E genotype and plasma levels of selected oxidative stress markers in both AD and MCI patients. APO E genotypes were determined using restriction enzyme analysis. Plasma levels of oxidative markers, advanced oxidation protein products, iron-reducing ability of plasma and, in MCI, activity of superoxide dismutases were evaluated using spectrophotometric analysis. We found, compared to controls, increased levels of oxidized proteins and decreased values of plasma-reducing capacity in both AD patients (p < 0.0001) and MCI patients (p < 0.001); the difference between AD and MCI patients was significant only for plasma-reducing capacity (p < 0.0001), the former showing the lowest values. Superoxide dismutase activity was reduced, although not at statistical level, in MCI compared with that in controls. E4 allele was statistically associated (p < 0.05) with AD patients. When comparing different APO E genotype subgroups, no difference was present, as far as advanced oxidation protein products and iron-reducing ability of plasma levels were concerned, between E4 and non-E4 carriers, in both AD and MCI; on the contrary, E4 carriers MCI patients showed significantly decreased (p < 0.05) superoxide dismutase activity with respect to non-E4 carriers. This study, in confirming the occurrence of oxidative stress in AD and MCI patients, shows how it can be related, at least for superoxide dismutase activity in MCI, to APO E4 allele risk factor.

Mechanisms involved in gastric protection of melatonin against oxidant stress by ischemia-reperfusion in rats.

PubMed

Cabeza, J; Motilva, V; Martín, M J; de la Lastra, C A

2001-02-09

The generation of oxygen-derived free radicals has been suggested to be significantly responsible for ischemia-reperfusion injury in gastrointestinal tissues. Biochemical mechanisms include the xanthine-oxidase-derived oxidants mainly the superoxide anion. Both in vitro and in vivo studies have demonstrated that the pineal hormone melatonin possesses free radical scavenging and antioxidant properties. The indolamine has been effective in reducing the induced-oxidative damage in several tissues and biological systems. The aim of this study was to elucidate additional antioxidant mechanisms responsible for the gastroprotection afforded by the indolamine in ischemia-reperfusion gastric injury. Therefore, changes of related enzymes such as xanthine-oxidase, superoxide dismutase, glutathione reductase and total glutathione were investigated. Our results showed that treatment with 5, 10 or 20 mg kg(-1) of melatonin, administered i.p., clearly diminished the percentage of damage to 49.56 +/- 17.20, 37.54 +/- 11.40 and 26.70 +/- 8.12 respectively. Histologically there was a reduction of exfoliation of superficial cells and blood cell infiltration. These protective effects were related to a significant reduction of xanthine-oxidase activity (2.23 +/- 0.38 U/mg prot x 10(-4) with the highest tested dose of melatonin) and significant increases in superoxide dismutase reaching a value of 6.20 +/- 0.56 U/mg prot with 25 mg/Kg of melatonin and glutation reductase activities (417.44 +/- 29.72 and 649.43 +/- 81.11 nmol/min/mg prot with 10 and 20 mg/Kg of melatonin). We conclude that the free radical scavenger properties of melatonin mainly of the superoxide anion, probably derived via the xanthine-oxidase pathway, and the increase of antioxidative enzymes significantly contributes to mediating the protection by the hormone against ischemia-reperfusion gastric injury.

Exercise training improves in vivo endothelial repair capacity of early endothelial progenitor cells in subjects with metabolic syndrome.

PubMed

Sonnenschein, Kristina; Horváth, Tibor; Mueller, Maja; Markowski, Andrea; Siegmund, Tina; Jacob, Christian; Drexler, Helmut; Landmesser, Ulf

2011-06-01

Endothelial dysfunction and injury are considered to contribute considerably to the development and progression of atherosclerosis. It has been suggested that intense exercise training can increase the number and angiogenic properties of early endothelial progenitor cells (EPCs). However, whether exercise training stimulates the capacity of early EPCs to promote repair of endothelial damage and potential underlying mechanisms remain to be determined. The present study was designed to evaluate the effects of moderate exercise training on in vivo endothelial repair capacity of early EPCs, and their nitric oxide and superoxide production as characterized by electron spin resonance spectroscopy analysis in subjects with metabolic syndrome. Twenty-four subjects with metabolic syndrome were randomized to an 8 weeks exercise training or a control group. Superoxide production and nitric oxide (NO) availability of early EPCs were characterized by using electron spin resonance (ESR) spectroscopy analysis. In vivo endothelial repair capacity of EPCs was examined by transplantation into nude mice with defined carotid endothelial injury. Endothelium-dependent, flow-mediated vasodilation was analysed using high-resolution ultrasound. Importantly, exercise training resulted in a substantially improved in vivo endothelial repair capacity of early EPCs (24.0 vs 12.7%; p < 0.05) and improved endothelium-dependent vasodilation. Nitric oxide production of EPCs was substantially increased after exercise training, but not in the control group. Moreover, exercise training reduced superoxide production of EPCs, which was not observed in the control group. The present study suggests for the first time that moderate exercise training increases nitric oxide production of early endothelial progenitor cells and reduces their superoxide production. Importantly, this is associated with a marked beneficial effect on the in vivo endothelial repair capacity of early EPCs in subjects with metabolic syndrome.

Quinone Reduction by the Na+-Translocating NADH Dehydrogenase Promotes Extracellular Superoxide Production in Vibrio cholerae▿ †

PubMed Central

Lin, Po-Chi; Türk, Karin; Häse, Claudia C.; Fritz, Günter; Steuber, Julia

2007-01-01

The pathogenicity of Vibrio cholerae is influenced by sodium ions which are actively extruded from the cell by the Na+-translocating NADH:quinone oxidoreductase (Na+-NQR). To study the function of the Na+-NQR in the respiratory chain of V. cholerae, we examined the formation of organic radicals and superoxide in a wild-type strain and a mutant strain lacking the Na+-NQR. Upon reduction with NADH, an organic radical was detected in native membranes by electron paramagnetic resonance spectroscopy which was assigned to ubisemiquinones generated by the Na+-NQR. The radical concentration increased from 0.2 mM at 0.08 mM Na+ to 0.4 mM at 14.7 mM Na+, indicating that the concentration of the coupling cation influences the redox state of the quinone pool in V. cholerae membranes. During respiration, V. cholerae cells produced extracellular superoxide with a specific activity of 10.2 nmol min−1 mg−1 in the wild type compared to 3.1 nmol min−1 mg−1 in the NQR deletion strain. Raising the Na+ concentration from 0.1 to 5 mM increased the rate of superoxide formation in the wild-type V. cholerae strain by at least 70%. Rates of respiratory H2O2 formation by wild-type V. cholerae cells (30.9 nmol min−1 mg−1) were threefold higher than rates observed with the mutant strain lacking the Na+-NQR (9.7 nmol min−1 mg−1). Our study shows that environmental Na+ could stimulate ubisemiquinone formation by the Na+-NQR and hereby enhance the production of reactive oxygen species formed during the autoxidation of reduced quinones. PMID:17322313

Measuring “Free” Iron Levels in Caenorhabditis Elegans Using Low-Temperature Fe(III) Electron Paramagnetic Resonance Spectroscopy

PubMed Central

Pate, Kira T.; Rangel, Natalie A.; Fraser, Brian; Clement, Matthew H. S.; Srinivasan, Chandra

2007-01-01

Oxidative stress, caused by free radicals within the body, has been associated with the process of aging and many human diseases. As free radicals, in particular superoxide, are difficult to measure, an alternative indirect method for measuring oxidative stress levels has been successfully used in E. coli and yeast. This method is based on a proposed connection between elevated superoxide levels and release of iron from solvent exposed [4Fe-4S] enzyme clusters, which eventually leads to an increase in hydroxyl radical production. In past studies using bacteria and yeast, a positive correlation was found between superoxide production or oxidative stress due to superoxide within the organism and EPR (electron paramagnetic resonance) detectable “free” iron levels. In the present study, we have developed a reliable and an efficient method for measuring “free” iron levels in C. elegans using low temperature Fe(III) EPR at g = 4.3. This method utilizes synchronized worm cultures grown on plates, which are homogenized and treated with desferrioxamine, an Fe(III) chelator, prior to packing the EPR tube. Homogenization was found not to alter “free” iron levels, while desferrioxamine treatment significantly raised these levels, indicating presence of both Fe(II) and Fe(III) in the “free” iron pool. The correlation between free radical levels and the observed “free” iron levels was examined by using heat stress and paraquat treatment. The intensity of the Fe(III) EPR signal and thus, the concentration of the “free” iron pool, varied with the treatments that altered radical levels without changing the total iron levels. This study provides the groundwork needed to uncover the correlation between oxidative stress, “free” iron levels, and longevity in C. elegans. PMID:17010298

Transgenic overexpression of uncoupling protein 2 attenuates salt-induced vascular dysfunction by inhibition of oxidative stress.

PubMed

Ma, Shuangtao; Wang, Qiang; Zhang, Yan; Yang, Dachun; Li, De; Tang, Bing; Yang, Yongjian

2014-03-01

Ablation of uncoupling protein 2 (UCP2) has been involved in the enhancement of salt sensitivity associated with increased superoxide level and decreased nitric oxide (NO) bioavailability. However, the role of overexpression of UCP2 in salt-induced vascular dysfunction remains elusive. UCP2 transgenic (TG) and wild-type (WT) mice were placed on either a normal-salt (NS, 0.5%) or a high-salt (HS, 8%) diet for 12 weeks. Blood pressure (BP) and hypotensive responses were measured, and the vascular tone, superoxide level, and NO bioavailability in aortas were measured in each group. The TG mice had increased expression and function of UCP2 in vascular smooth muscle cells. The acetylcholine (ACh)- and nitroglycerin (NTG)-induced hypotensive responses and aortic relaxations were significantly blunted in WT mice fed with an HS diet compared with an NS diet. These harmful effects were prevented in UCP2 TG mice. The impairments of ACh- and NTG-induced relaxation in aorta were inhibited by the endothelial NO synthase (eNOS) inhibitor L-NAME and mitochondrial antioxidant MitoQ, respectively. The HS intake led to a significant increase in superoxide production and a comparable decrease in NO bioavailability in aortas, and these effects were blunted in UCP2 TG mice. The expression of UCP2 was slightly increased in the HS group. However, the expression and phosphorylation of eNOS were not affected by an HS diet and overexpression of UCP2. These findings suggest that overexpression of UCP2 can ameliorate salt-induced vascular dysfunction. This beneficial effect of UCP2 is mediated by decreased superoxide and reserved NO bioavailability.

Cross-Reactivity of Schistosoma mansoni Cytosolic Superoxide Dismutase, a Protective Vaccine Candidate, with Host Superoxide Dismutase and Identification of Parasite-Specific B Epitopes

PubMed Central

Carvalho-Queiroz, Claudia; Cook, Rosemary; Wang, Ching C.; Correa-Oliveira, Rodrigo; Bailey, Nicola A.; Egilmez, Nejat K.; Mathiowitz, Edith; LoVerde, Philip T.

2004-01-01

Schistosoma mansoni, an intravascular parasite, has evolved a number of immune evasion mechanisms to establish itself in the host, such as antioxidant enzymes. Our laboratory has demonstrated that the highest levels of certain antioxidant enzymes are found in adult worms, which are the least susceptible to immune killing. Vaccination of mice with naked DNA constructs containing the gene encoding Cu/Zn cytosolic superoxide dismutase (SmCT-SOD) showed significant levels of protection compared to a control group, and our data demonstrate that the adult worms are a target of the immune response that confers resistance in SmCT-SOD DNA-vaccinated mice. Because SmCT-SOD shows significant identity with the human homologue, we evaluated the reactivity of anti-SmCT-SOD antibodies derived from SmCT-SOD-immunized mice and rabbits and from S. mansoni-infected individuals to human superoxide dismutase (hSOD) and SmCT-SOD parasite-specific peptides to assess the potential for autoimmune responses from immunization with the recombinant molecule. In addition, we evaluated the ability of various SmCT-SOD adjuvant-delivered immunizations to induce cross-reactive antibodies. Both mouse and rabbit antibodies generated against SmCT-SOD recognized the denatured form of hSOD. The same antibodies did not recognize nondenatured hSOD. Sera from infected individuals with different clinical forms of schistosomiasis recognized SmCT-SOD but not hSOD. Antibodies from mice immunized with different SmCT-SOD-containing formulations of both DNA and protein were able to recognize SmCT-SOD-derived peptides but not soluble hSOD. All together, these findings serve as a basis for developing a subunit vaccine against schistosomiasis. PMID:15102772

Two novel cyanobacterial bioluminescent whole-cell bioreporters based on superoxide dismutases MnSod and FeSod to detect superoxide anion.

PubMed

Hurtado-Gallego, J; Martín-Betancor, K; Rodea-Palomares, I; Leganés, F; Rosal, R; Fernández-Piñas, F

2018-06-01

This work describes the construction of two novel self-luminescent bioreporter strains of the cyanobacterium Nostoc sp. PCC 7120 by fusing the promoter region of the sodA and sodB genes (encoding the superoxide dismutases MnSod and FeSod, respectively) to luxCDABE from Photorhabdus luminescens aimed at detecting pollutants that generate reactive oxygen species (ROS), particularly O 2 - . Bioreporters were tested against methyl viologen (MV) as the inducer of superoxide anion (O 2 - ). Both bioreporters were specific for O 2 - and Limits of detection (LODs) and Maximum Permissive Concentrations (MPCs) were calculated: Nostoc sp. PCC 7120 pBG2154 (sodA) had a range of detection from 400 to 1000 pM of MV and for Nostoc sp. PCC 7120 pBG2165 (sodB) the range of detection was from 500 to 1800 pM of MV after 5 h-exposure. To further validate the bioreporters, they were tested with the emerging pollutant Triclosan which induced bioluminescence in both strains. Furthermore, the bioreporters performance was tested in two real environmental samples with different water matrix complexity, spiked with MV. Both bioreporters were induced by O 2 - in these environmental samples. In the case of the river water sample, the amount of bioavailable MV as calculated from the bioreporters output was similar to that nominally added. For the waste water sample, the bioavailable MV concentration detected by the bioreporters was one order of magnitude lower than nominal. These differences could be due to MV complexation with organic matter and/or co-occurring organic contaminants. These results confirm their high sensitivity to O 2 - and their suitability to detect oxidative stress-generating pollutants in fresh-waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

Pioglitazone inhibits LOX-1 expression in human coronary artery endothelial cells by reducing intracellular superoxide radical generation.

PubMed

Mehta, Jawahar L; Hu, Bo; Chen, Jiawei; Li, Dayuan

2003-12-01

LOX-1, a novel lectin-like receptor for oxidized LDL (ox-LDL), is expressed in response to ox-LDL, angiotensin II (Ang II), tumor necrosis factor (TNF)-alpha, and other stress stimuli. It is highly expressed in atherosclerotic tissues. Peroxisome proliferator-activated receptor (PPAR)-gamma ligands, such as pioglitazone, exert antiatherosclerotic effects. This study examined the regulation of LOX-1 expression in human coronary artery endothelial cells (HCAECs) by pioglitazone. Fourth generation HCAECs were treated with ox-LDL, Ang II, or TNF-alpha with or without pioglitazone pretreatment. All 3 stimuli upregulated LOX-1 expression (mRNA and protein). Pioglitazone, in a concentration-dependent manner, reduced LOX-1 expression (P<0.01 versus ox-LDL, Ang II, or TNF-alpha alone). Ox-LDL, Ang II, and TNF-alpha each enhanced intracellular superoxide radical generation, and pioglitazone pretreatment reduced superoxide generation (P<0.01 versus ox-LDL, Ang II, or TNF-alpha). Furthermore, all 3 stimuli upregulated the expression of the transcription factors nuclear factor-kappaB and activator protein-1 (determined by electrophoretic mobility shift assay), and pioglitazone pretreatment reduced this expression (P<0.01 versus ox-LDL, Ang II, or TNF-alpha). To determine the biological significance of pioglitazone-mediated downregulation of LOX-1, we studied monocyte adhesion to ox-LDL-treated HCAECs. Pioglitazone reduced the adhesion of monocytes to activated HCAECs in a fashion similar to that produced by antisense to LOX-1 mRNA. These observations suggest that the PPAR-gamma ligand pioglitazone reduces intracellular superoxide radical generation and subsequently reduces the expression of transcription factors, expression of the LOX-1 gene, and monocyte adhesion to activated endothelium. The salutary effect of PPAR-gamma ligands in atherogenesis may involve the inhibition of LOX-1 and the adhesion of monocytes to endothelium.

Senescence marker protein-30/superoxide dismutase 1 double knockout mice exhibit increased oxidative stress and hepatic steatosis

PubMed Central

Kondo, Yoshitaka; Masutomi, Hirofumi; Noda, Yoshihiro; Ozawa, Yusuke; Takahashi, Keita; Handa, Setsuko; Maruyama, Naoki; Shimizu, Takahiko; Ishigami, Akihito

2014-01-01

Superoxide dismutase 1 (SOD1) is an antioxidant enzyme that converts superoxide anion radicals into hydrogen peroxide and molecular oxygen. The senescence marker protein-30 (SMP30) is a gluconolactonase that functions as an antioxidant protein in mammals due to its involvement in ascorbic acid (AA) biosynthesis. SMP30 also participates in Ca2+ efflux by activating the calmodulin-dependent Ca2+-pump. To reveal the role of oxidative stress in lipid metabolism defects occurring in non-alcoholic fatty liver disease pathogenesis, we generated SMP30/SOD1-double knockout (SMP30/SOD1-DKO) mice and investigated their survival curves, plasma and hepatic lipid profiles, amounts of hepatic oxidative stress, and hepatic protein levels expressed by genes related to lipid metabolism. While SMP30/SOD1-DKO pups had no growth retardation by 14 days of age, they did have low plasma and hepatic AA levels. Thereafter, 39% and 53% of male and female pups died by 15–24 and 89 days of age, respectively. Compared to wild type, SMP30-KO and SOD1-KO mice, by 14 days SMP30/SOD1-DKO mice exhibited: (1) higher plasma levels of triglyceride and aspartate aminotransferase; (2) severe accumulation of hepatic triglyceride and total cholesterol; (3) higher levels of superoxide anion radicals and thiobarbituric acid reactive substances in livers; and (4) decreased mRNA and protein levels of Apolipoprotein B (ApoB) in livers – ApoB is an essential component of VLDL secretion. These results suggest that high levels of oxidative stress due to concomitant deficiency of SMP30 and/or AA, and SOD1 cause abnormal plasma lipid metabolism, hepatic lipid accumulation and premature death resulting from impaired VLDL secretion. PMID:25003023

[Activity of antioxidative enzymes of the myocardium during ischemia].

PubMed

Gutkin, D V; Petrovich, Iu A

1982-01-01

Activation of lipid peroxidation during myocardial ischemia may be determined by the reduction of the enzymatic antioxidant cell protection. Such a conclusion has been drawn on the basis of an analysis of variation in the activity of superoxide dismutase, glutathion peroxidase and catalase in experimental myocardial ischemia in rats, induced by ligation of the left descending artery of the heart. In the early period of ischemia (1-3 h) the activity of superoxide dismutase and glutation peroxidase markedly decreases. In the periischemic zone, the fall in the enzymatic activity is not so pronounced. The activity of the enzymes does not reach the basic level 5 days after the operation.

[Status of the lipid peroxidation system in the tissues of rats following a 7-day flight on the Kosmos-1667 biosatellite].

PubMed

Delenian, N V; Markin, A A

1989-01-01

Rats flown for 7 days on Cosmos-1667 were for the first time used to measure antioxidative enzymes (superoxide dismutase, glutathione peroxidase, glutathione reductase, catalase), lipid peroxidation products (diene conjugates, malonic dialdehyde, Schiff bases) and tocopherol. Enhanced lipid peroxidation in the heart was completely compensated by activation of antioxidative enzymes. The content of all lipid peroxidation products measured in the liver increased; this was accompanied by a decrease of glutathione peroxidase and an increase of superoxide dismutase activities. It is suggested that lipid peroxidation was activated in response to altered gravity.

Superoxide Dismutase (SOD)-mimetic M40403 Is Protective in Cell and Fly Models of Paraquat Toxicity

PubMed Central

Filograna, Roberta; Godena, Vinay K.; Sanchez-Martinez, Alvaro; Ferrari, Emanuele; Casella, Luigi; Beltramini, Mariano; Bubacco, Luigi; Whitworth, Alexander J.; Bisaglia, Marco

2016-01-01

Parkinson disease is a debilitating and incurable neurodegenerative disorder affecting ∼1–2% of people over 65 years of age. Oxidative damage is considered to play a central role in the progression of Parkinson disease and strong evidence links chronic exposure to the pesticide paraquat with the incidence of the disease, most probably through the generation of oxidative damage. In this work, we demonstrated in human SH-SY5Y neuroblastoma cells the beneficial role of superoxide dismutase (SOD) enzymes against paraquat-induced toxicity, as well as the therapeutic potential of the SOD-mimetic compound M40403. Having verified the beneficial effects of superoxide dismutation in cells, we then evaluated the effects using Drosophila melanogaster as an in vivo model. Besides protecting against the oxidative damage induced by paraquat treatment, our data demonstrated that in Drosophila M40403 was able to compensate for the loss of endogenous SOD enzymes, acting both at a cytosolic and mitochondrial level. Because previous clinical trials have indicated that the M40403 molecule is well tolerated in humans, this study may have important implication for the treatment of Parkinson disease. PMID:26953346

The preparation and antioxidant activity of the sulfanilamide derivatives of chitosan and chitosan sulfates.

PubMed

Zhong, Zhimei; Ji, Xia; Xing, Ronge; Liu, Song; Guo, Zhanyong; Chen, Xiaolin; Li, Pengcheng

2007-06-01

Chitosan (CS) and chitosan sulfates (CSS) with different molecular weight (Mw) were reacted with 4-acetamidobenzene sulfonyl chloride to obtain sulfanilamide derivatives of chitosan and chitosan sulfates (LSACS, HSACS, LSACSS, HSACSS). The preparation conditions such as different reaction time, temperature, solvent, and the molar ratio of reaction materials are discussed in this paper. Their structures were characterized by FTIR spectroscopy and elemental analyses. The antioxidant activities of the derivatives were investigated employing various established in vitro systems, such as hydroxyl-radical ((*)OH) superoxide anion (O2(*-)) scavenging and reducing power. All kinds of the compounds (HCS, LCS, HCSS, LCSS, HSACS, LSACS, HSACSS, LSACSS) showed stronger scavenging activity on hydroxyl radical than ascorbic acid (Vc). The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were obvious. The experiment showed that the superoxide radical scavenging effect of sulfanilamide derivatives of chitosan and chitosan sulfates was stronger than that of original CS and CSS. All of the derivatives were efficient in the reducing power. The results indicated that the sulfanilamide group were grafted on CS and CSS increased the reducing power of them obviously.

Physiological and biochemical responses of Prorocentrum minimum to high light stress

NASA Astrophysics Data System (ADS)

Park, So Yun; Choi, Eun Seok; Hwang, Jinik; Kim, Donggiun; Ryu, Tae Kwon; Lee, Taek-Kyun

2009-12-01

Prorocentrum minimum is a common bloomforming photosynthetic dinoflagellate found along the southern coast of Korea. To investigate the adaptive responses of P. minimum to high light stress, we measured growth rate, and generation of reactive oxidative species (ROS), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) in cultures exposed to normal (NL) and high light levels (HL). The results showed that HL (800 μmol m-2 s-1) inhibited growth of P. minimum, with maximal inhibition after 7-9 days. HL also increased the amount of ROS and MDA, suggesting that HL stress leads to oxidative damage and lipid peroxidation in this species. Under HL, we first detected superoxide on day 4 and H2O2 on day 5. We also detected SOD activity on day 5 and CAT activity on day 6. The level of lipid peroxidation, an indicator of cell death, was high on day 8. Addition of diphenyleneiodonium (DPI), an NAD(P)H inhibitor, decreased the levels of superoxide generation and lipid peroxidation. Our results indicate that the production of ROS which results from HL stress in P. minimum also induces antioxidative enzymes that counteract oxidative damage and allow P. minimum to survive.

Biomaterial associated impairment of local neutrophil function.

PubMed

Kaplan, S S; Basford, R E; Kormos, R L; Hardesty, R L; Simmons, R L; Mora, E M; Cardona, M; Griffith, B L

1990-01-01

The effect of biomaterials on neutrophil function was studied in vitro to determine if these materials activated neutrophils and to determine the subsequent response of these neutrophils to further stimulation. Two biomaterials--polyurethane, a commonly used substance, and Velcro pile (used in the Jarvik 7 heart)--were evaluated. Two control substances, polyethylene and serum-coated polystyrene, were used for comparison. Neutrophil superoxide release was measured following incubation with these materials for 10, 30, and 120 min in the absence of additional stimulation and after stimulation with formylmethionylleucylphenylalanine (fMLP) or phorbol myristate acetate (PMA). The authors observed that the incubation of neutrophils on both polyurethane and Velcro resulted in substantially increased superoxide release that was greater after the 10 min than after the 30 or 120 min association. These activated neutrophils exhibited a poor additional response to fMLP but responded well to PMA. The effect of implantation of the Novacor left ventricular assist device on peripheral blood neutrophil function was also evaluated. The peripheral blood neutrophils exhibited normal superoxide release and chemotaxis. These studies suggest that biomaterials may have a profound local effect on neutrophils, which may predispose the patient to periprosthetic infection, but that the reactivity of circulating neutrophils is unimpaired.

BPA-toxicity via superoxide anion overload and a deficit in β-catenin signaling in human bone mesenchymal stem cells.

PubMed

Leem, Yea-Hyun; Oh, Seikwan; Kang, Hong-Je; Kim, Jung-Hwa; Yoon, Juno; Chang, Jae-Suk

2017-01-01

Bisphenol A (BPA), used in the manufacture of products based on polycarbonate plastics and epoxy resins, is well known as an endocrine-disrupting monomer. In the current study, BPA increased cytotoxicity in hBMSCs in a dose- and time-dependent manner, concomitantly with increased lipid peroxidation. Increased cell death in BPA-treated cells was markedly blocked by pretreatment with the superoxide dismutase mimetic MnTBAP and MnTMPyP, but not by catalase, glutathione, the glutathione peroxidase mimetic ebselen, the NOS inhibitor NAME, or the xanthine oxidase inhibitor allopurinol. Furthermore, the decline in nuclear β-catenin and cyclin D1 levels in hBMSCs exposed to BPA was reversed by MnTBAP treatment. Finally, treatment of hBMSCs with the GSK3β inhibitor LiCl 2 increased nuclear β-catenin levels and significantly attenuated cytotoxicity compared with BPA treatment. Our current results in hBMSCs exposed to BPA suggest that BPA causes a disturbance in β-catenin signaling via a superoxide anion overload. © 2016 The Authors Environmental Toxicology Published by Wiley Periodicals, Inc. Environ Toxicol 32: 344-352, 2017. © 2016 The Authors Environmental Toxicology Published by Wiley Periodicals, Inc.

Physical and chemical stability of different formulations with superoxide dismutase.

PubMed

Di Mambro, V M; Campos, P M B G Maia; Fonseca, M J V

2004-10-01

Topical formulations with superoxide dismutase (SOD), a scavenger of superoxide radicals, have proved to be effective against some skin diseases. Nevertheless, formulations with proteins are susceptible to both chemical and physical instability. Three different formulations (anionic and non-ionic gel and emulsion) were developed and supplemented with SOD in order to determine the most stable formulation that would maintain SOD activity. Physical stability was evaluated by assessing the rheological behavior of the formulations stored at room temperature, 37 and 45 degrees C. Chemical stability was evaluated by the measurement of enzymatic activity in the formulations stored at room temperature and at 45 degrees C. Formulations showed a flow index less than one, characterizing pseudoplastic behavior. There was no significant difference in initial values of flow index, tixotropy or minimum apparent viscosity. Neither gel showed significant changes in minimum apparent viscosity concerning storage time or temperature, as well, SOD presence and its activity. The emulsion showed decreased viscosity by the 28th day, but no significant changes concerning storage temperature or SOD presence, although it showed a decreased activity. The addition of SOD to the formulations studied did not affect their physical stability but gel formulations seem to be better bases for enzyme addition.

The stimulation of superoxide anion production in guinea-pig peritoneal macrophages and neutrophils by phorbol myristate acetate, opsonized zymosan and IgG2-containing soluble immune complexes.

PubMed Central

Baxter, M A; Leslie, R G; Reeves, W G

1983-01-01

The kinetics of superoxide anion production in guinea-pig peritoneal macrophages and neutrophils were determined following in vitro stimulation with phorbol myristate acetate (PMA), opsonized zymosan (OZ) and soluble immune complexes of guinea-pig IgG2 (SIC). Superoxide production was recorded as chemiluminescence (CL) arising from the reductive cleavage of lucigenin. With PMA, both macrophages and neutrophils displayed a two-phase response consisting of a rapid initial burst of CL, which preceded ligand ingestion, followed by a plateau in the CL response which persisted for more than 30 min. By contrast, OZ induced a slow progressive increase in CL in both phagocytes which was consistent with the development of an oxidative burst concomitant with ingestion. The phagocytes differed in their responses to SIC, the macrophages displaying CL kinetics similar to those observed with PMA, whereas the neutrophils responded in the manner observed with OZ. The relationship between disparity in the patterns of macrophage and neutrophil CL responses to SIC and differences in their expression of Fc receptors for IgG2 (Coupland & Leslie, 1983) is discussed. PMID:6299935

Anti-inflammatory triterpenoids from the stems of Microtropis fokienensis.

PubMed

Chen, I-Hsiao; Du, Ying-Chi; Hwang, Tsong-Long; Chen, I-Fen; Lan, Yu-Hsuan; Yen, Hsin-Fu; Chang, Fang-Rong; Wu, Yang-Chang

2014-04-14

Three new ursane- and four new oleanane- type triterpenoids 1-7 were isolated, along with six known compounds 8-13, from the methanolic extract of Microtropis fokienensis. All structures were elucidated by mass and NMR spectroscopic methods. The isolates 4-10 and known compounds 14-17 that were previously isolated from this material were evaluated for anti-inflammatory activity based on effects against superoxide anion generation and elastase release by neutrophils in response to fMLP/CB. 11α,30-Dihydroxy-2,3-seco-olean-12-en-2,3-dioic anhydride (7) was the first triterpene anhydride from the genus of Microtropis to have the ring A expanded to a seven-membered ring; it showed significant anti-inflammatory activity against superoxide anion generation and elastase release. Unexpectedly, 30-hydroxy-2,3-seco-lup-20(29)-ene-2,3-dioic acid (17) showed the best effect against superoxide anion generation and elastase release with IC50 values of 0.06±0.01 and 1.03±0.35 µg/mL, respectively. Compound 17 had a dioic acid function, and compound 7 had an anhydride function modification in ring A; both showed promising activity in the target assays.

Polyphenolic content and antioxidant activity of some wild Saudi Arabian Asteraceae plants.

PubMed

Shahat, Abdelaaty A; Ibrahim, Abeer Y; Elsaid, Mansour S

2014-07-01

To study the antioxidant properties of crude extract of different Asteraceae plants. The antioxidant properties of six extracts were evaluated using different antioxidant tests, including free radical scavenging, reducing power, metal chelation, superoxide anion radical scavenging, total antioxidant capacity and inhibition of lipid peroxidation activities. Picris cyanocarpa (P. cyanocarpa) and Anthemis deserti (A. deserti) had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger while Achillia fragrantissima (A. fragrantissima) and Artemissia monosperma (A. monosperma) were the most efficient as ion chelator (100% at 100, 200 and 400 μg/mL) A. fragrantissima and Rhantarium appoposum (R. appoposum) showed 100% inhibition on peroxidation of linoleic acid emulsion at 200 and 400 μg/mL, while butylatedhydroxy toluene and ascorbic acid showed 100 and 95% inhibition percentage at 400 μg/mL, respectively. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyl toluene and ascorbic acid. In most tests P. cyanocarpa and A. deserti had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Effect of stationary magnetic field strengths of 150 and 200 mT on reactive oxygen species production in soybean.

PubMed

Shine, M B; Guruprasad, K N; Anand, Anjali

2012-07-01

Our previous investigation reported the beneficial effect of pre-sowing magnetic treatment for improving germination parameters and biomass accumulation in soybean. In this study, soybean seeds treated with static magnetic fields of 150 and 200 mT for 1 h were evaluated for reactive oxygen species (ROS) and activity of antioxidant enzymes. Superoxide and hydroxyl radicals were measured in embryos and hypocotyls of germinating seeds by electron paramagnetic resonance spectroscopy and kinetics of superoxide production; hydrogen peroxide and antioxidant activities were estimated spectrophotometrically. Magnetic field treatment resulted in enhanced production of ROS mediated by cell wall peroxidase while ascorbic acid content, superoxide dismutase and ascorbate peroxidase activity decreased in the hypocotyl of germinating seeds. An increase in the cytosolic peroxidase activity indicated that this antioxidant enzyme had a vital role in scavenging the increased H(2)O(2) produced in seedlings from the magnetically treated seeds. Hence, these studies contribute to our first report on the biochemical basis of enhanced germination and seedling growth in magnetically treated seeds of soybean in relation to increased production of ROS. Copyright © 2012 Wiley Periodicals, Inc.

In vivo antioxidant activity of deacetylasperulosidic Acid in noni.

PubMed

Ma, De-Lu; Chen, Mai; Su, Chen X; West, Brett J

2013-01-01

Deacetylasperulosidic acid (DAA) is a major phytochemical constituent of Morinda citrifolia (noni) fruit. Noni juice has demonstrated antioxidant activity in vivo and in human trials. To evaluate the role of DAA in this antioxidant activity, Wistar rats were fed 0 (control group), 15, 30, or 60 mg/kg body weight per day for 7 days. Afterwards, serum malondialdehyde concentration and superoxide dismutase and glutathione peroxidase activities were measured and compared among groups. A dose-dependent reduction in malondialdehyde was evident as well as a dose-dependent increase in superoxide dismutase activity. DAA ingestion did not influence serum glutathione peroxidase activity. These results suggest that DAA contributes to the antioxidant activity of noni juice by increasing superoxide dismutase activity. The fact that malondialdehyde concentrations declined with increased DAA dose, despite the lack of glutathione peroxidase-inducing activity, suggests that DAA may also increase catalase activity. It has been previously reported that noni juice increases catalase activity in vivo but additional research is required to confirm the effect of DAA on catalase. Even so, the current findings do explain a possible mechanism of action for the antioxidant properties of noni juice that have been observed in human clinical trials.

In Vivo Antioxidant Activity of Deacetylasperulosidic Acid in Noni

PubMed Central

Ma, De-Lu; Chen, Mai; Su, Chen X.; West, Brett J.

2013-01-01

Deacetylasperulosidic acid (DAA) is a major phytochemical constituent of Morinda citrifolia (noni) fruit. Noni juice has demonstrated antioxidant activity in vivo and in human trials. To evaluate the role of DAA in this antioxidant activity, Wistar rats were fed 0 (control group), 15, 30, or 60 mg/kg body weight per day for 7 days. Afterwards, serum malondialdehyde concentration and superoxide dismutase and glutathione peroxidase activities were measured and compared among groups. A dose-dependent reduction in malondialdehyde was evident as well as a dose-dependent increase in superoxide dismutase activity. DAA ingestion did not influence serum glutathione peroxidase activity. These results suggest that DAA contributes to the antioxidant activity of noni juice by increasing superoxide dismutase activity. The fact that malondialdehyde concentrations declined with increased DAA dose, despite the lack of glutathione peroxidase-inducing activity, suggests that DAA may also increase catalase activity. It has been previously reported that noni juice increases catalase activity in vivo but additional research is required to confirm the effect of DAA on catalase. Even so, the current findings do explain a possible mechanism of action for the antioxidant properties of noni juice that have been observed in human clinical trials. PMID:24371540

Effect of the chelation of metal cation on the antioxidant activity of chondroitin sulfates.

PubMed

Ajisaka, Katsumi; Oyanagi, Yutaka; Miyazaki, Tatsuo; Suzuki, Yasuhiro

2016-06-01

The antioxidant potencies of chondroitin sulfates (CSs) from shark cartilage, salmon cartilage, bovine trachea, and porcine intestinal mucosa were compared by three representative methods for the measurement of the antioxidant activity; DPPH radical scavenging activity, superoxide radical scavenging activity, and hydroxyl radical scavenging activity. CSs from salmon cartilage and bovine trachea showed higher potency in comparison with CSs from shark cartilage and porcine intestinal mucosa. Next, CS from salmon cartilage chelating with Ca(2+), Mg(2+), Mn(2+), or Zn(2+) were prepared, and their antioxidant potencies were compared. CS chelating with Ca(2+) or Mg(2+) ions showed rather decreased DPPH radical scavenging activity in comparison with CS of H(+) form. In contrast, CS chelating with Ca(2+) or Mg(2+) ion showed remarkably enhanced superoxide radical scavenging activity than CS of H(+) or Na(+) form. Moreover, CS chelating with divalent metal ions, Ca(2+), Mg(2+), Mn(2+), or Zn(2+), showed noticeably higher hydroxyl radical scavenging activity than CS of H(+) or Na(+) form. The present results revealed that the scavenging activities of, at least, superoxide radical and hydroxyl radical were enhanced by the chelation with divalent metal ions.

Effect of sodium benzoate preservative on micronucleus induction, chromosome break, and Ala40Thr superoxide dismutase gene mutation in lymphocytes.

PubMed

Pongsavee, Malinee

2015-01-01

Sodium benzoate is food preservative that inhibits microbial growth. The effects of sodium benzoate preservative on micronucleus induction, chromosome break, and Ala40Thr superoxide dismutase gene mutation in lymphocytes were studied. Sodium benzoate concentrations of 0.5, 1.0, 1.5, and 2.0 mg/mL were treated in lymphocyte cell line for 24 and 48 hrs, respectively. Micronucleus test, standard chromosome culture technique, PCR, and automated sequencing technique were done to detect micronucleus, chromosome break, and gene mutation. The results showed that, at 24- and 48-hour. incubation time, sodium benzoate concentrations of 1.0, 1.5, and 2.0 mg/mL increased micronucleus formation when comparing with the control group (P < 0.05). At 24- and 48-hour. incubation time, sodium benzoate concentrations of 2.0 mg/mL increased chromosome break when comparing with the control group (P < 0.05). Sodium benzoate did not cause Ala40Thr (GCG→ACG) in superoxide dismutase gene. Sodium benzoate had the mutagenic and cytotoxic toxicity in lymphocytes caused by micronucleus formation and chromosome break.

A lithium-oxygen battery based on lithium superoxide.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Jun; Lee, Yun Jung; Luo, Xiangyi

Although the superoxide of lithium (LiO2) is believed to be a key intermediate in Li-O2 batteries leading to the formation of lithium peroxide, LiO2 has never been observed in its pure state. In this work, we provide evidence that use of a cathode based on a reduced graphene oxide with Ir nanoparticles in a Li-O2 battery results in a LiO2 discharge product formed by single electron transfer without further electron transfer or disproportionation to form Li2O2. High energy X-ray diffraction (HE-XRD) patterns indicates the presence of crystalline LiO2 with no evidence of Li2O2 or Li2O. The HEXRD studies as amore » function of time also show that LiO2 can be stable in its crystalline form after one week of aging in the presence of electrolyte. The results provide evidence that LiO2 is stable enough that it can be repeatedly charged and discharged with a very low charge potential (~3.2 V) and may open the avenue for a lithium superoxide-based battery.« less

BPA‐toxicity via superoxide anion overload and a deficit in β‐catenin signaling in human bone mesenchymal stem cells

PubMed Central

Oh, Seikwan; Kang, Hong‐Je; Kim, Jung‐Hwa; Yoon, Juno

2016-01-01

ABSTRACT Bisphenol A (BPA), used in the manufacture of products based on polycarbonate plastics and epoxy resins, is well known as an endocrine‐disrupting monomer. In the current study, BPA increased cytotoxicity in hBMSCs in a dose‐ and time‐dependent manner, concomitantly with increased lipid peroxidation. Increased cell death in BPA‐treated cells was markedly blocked by pretreatment with the superoxide dismutase mimetic MnTBAP and MnTMPyP, but not by catalase, glutathione, the glutathione peroxidase mimetic ebselen, the NOS inhibitor NAME, or the xanthine oxidase inhibitor allopurinol. Furthermore, the decline in nuclear β‐catenin and cyclin D1 levels in hBMSCs exposed to BPA was reversed by MnTBAP treatment. Finally, treatment of hBMSCs with the GSK3β inhibitor LiCl2 increased nuclear β‐catenin levels and significantly attenuated cytotoxicity compared with BPA treatment. Our current results in hBMSCs exposed to BPA suggest that BPA causes a disturbance in β‐catenin signaling via a superoxide anion overload. © 2016 The Authors Environmental Toxicology Published by Wiley Periodicals, Inc. Environ Toxicol 32: 344–352, 2017. PMID:26822619

Lithium Superoxide Hydrolysis and Relevance to Li–O 2 Batteries

DOE PAGES

Wang, Hsien -Hau; Lee, Yun Jung; Assary, Rajeev S.; ...

2017-04-17

Fundamental understanding of reactions of lithium peroxides and superoxides is essential for the development of Li–O 2 batteries. In this context, an investigation is reported of the hydrolysis of lithium superoxide, which has recently been synthesized in a Li–O 2 battery. Surprisingly, the hydrolysis of solid LiO 2 is significantly different from that of NaO 2 and KO 2. Unlike KO 2 and NaO 2, the hydrolysis of LiO 2 does not produce H 2O 2. Similarly, the reactivity of Li 2O 2 toward water differs from LiO 2, in that Li 2O 2 results in H 2O 2 asmore » a product. The difference in the LiO 2 reactivity with water is due to the more exothermic nature of the formation of LiOH and O 2 compared with the corresponding reactions of NaO 2 and KO 2. Here, we also show that a titration method used in this study, based on reaction of the discharge product with a Ti(IV)OSO 4 solution, provides a useful diagnostic technique to provide information on the composition of a discharge product in a Li–O 2 battery.« less

Influence of Rhodococcus equi on the respiratory burst of resident alveolar macrophages from horses

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brumbaugh, G.W.

1986-01-01

Rhodococcus equi is the etiologic agent of a devastating pneumonia of sporadic incidence in foals. The purpose of this study was to evaluate the influence of R. equi on the superoxide anion production, measured spectrophotometrically as the reduction of cytochrome C, and hexose monophosphate shunt activity, measured by /sup 14/CO/sub 2/ liberation from /sup 14/C-1-D-glucose, of alveolar macrophages from horses. Alveolar macrophages were harvested from 6 anesthetized, healthy, light-breed, adult horses by bronchoalveolar lavage. Following a randomized complete block design, the suspension of cells was divided into aliquots of 10/sup 6/ viable alveolar macrophages which were exposed to 1, 10more » or 100 g. of opsonized R. equi or opsonized zymosan A at 37 C for 2 hours. In this study the respiratory burst of equine alveolar macrophages was only evidenced by the hexose monophosphate shunt activity and superoxide anion was not coincidentally produced. Rhodococcus equi did not adversely affect that response. The insignificant superoxide anion production by the alveolar macrophages suggests that this may not be a significant oxygen metabolite in those cells.« less

Purification and characterization of two iron superoxide dismutases of Phytomonas sp. isolated from Euphorbia characias (plant trypanosomatids).

PubMed

Marín, C; Rodríguez-González, I; Hitos, A B; Rosales, M J; Dollet, M; Sánchez-Moreno, M

2004-07-01

Two superoxide dismutases (SODI and SODII) have been purified by differential centrifugation, fractionation with ammonium sulphate followed by chromatographic separation (ionic exchange and affinity), from a plant trypanosomatid isolated from Euphorbia characias, and then characterized for several biochemical properties. Both enzymes were insensitive to cyanide but sensitive to hydrogen peroxide, properties characteristic of iron-containing superoxide dismutase. SODI had a molecular mass of approximately 66 kDa, whereas the molecular mass of SODII was approximately 22 kDa, both enzymes showing single bands. The isoelectric points of SODI and SODII were 6.8 and 3.6, respectively. The enzymatic stability persisted at least for 6 months when the sample was lyophilized and preserved at -80 degrees C. Digitonin titration and subcellular fractionation showed that both enzymes were in the cytoplasmic fraction, although part of SODII isoenzyme was also associated with glycosomes. We assayed these activities (SOD) in 18 trypanosomatid isolates on isoelectric focusing gels, and have demonstrated that the SOD is a biochemical marker sufficient to identify a trypanosomatid isolated from a plant as belonging to the genus Phytomonas and to distinguish between a true Phytomonas and other trypanosomatids that are capable of causing transient infections in plants.

Effects of exercise preconditioning on intestinal ischemia-reperfusion injury.

PubMed

Gokbel, H; Oz, M; Okudan, N; Belviranli, M; Esen, H

2014-01-01

To investigate the effects of exercise preconditioning on oxidative injury in the intestinal tissue of rats. Sixty male Wistar rats were randomly divided into six groups as sham (n = 10), ischemia-reperfusion (n = 10), exercise (n = 10), exercise plus ischemia-reperfusion (n = 10), ischemic preconditioning (n = 10), and ischemic preconditioning plus ischemia-reperfusion groups (n = 10). Tissue levels of malondialdehyde and activities of myeloperoxidase and superoxide dismutase, and serum levels of tumor necrosis factor-alpha and interleukin-6 were measured. Intestinal tissue histopathology was also evaluated by light microscopy. Tumor necrosis factor-alpha concentrations significantly decreased in the exercise group compared to the sham group (p < 0.05). Myeloperoxidase activity significantly increased and superoxide dismutase activity significantly decreased in ischemia-reperfusion group compared to the sham group (p < 0.05). Superoxide dismutase activity in the ischemic preconditioning and ischemic preconditioning plus ischemia-reperfusion groups were significantly higher compared to the ischemia-reperfusion and exercise groups (p < 0.05). Histopathologically, intestinal injury significantly attenuated in the exercise plus ischemia-reperfusion group compared to the ischemia-reperfusion group. The results of the present study indicate that exercise training seems to have a protective role against intestinal ischemia-reperfusion injury (Tab. 3, Fig. 1, Ref. 35).

Quenching of Superoxide Radicals by Green Fluorescent Protein

PubMed Central

Bou-Abdallah, Fadi; Chasteen, N. Dennis; Lesser, Michael P.

2006-01-01

Green fluorescent protein (GFP) is a widely used in vivo molecular marker. These proteins are particularly resistant, and maintain function, under a variety of cellular conditions such as pH extremes and elevated temperatures. Green fluorescent proteins are also abundant in several groups of marine invertebrates including reef-forming corals. While molecular oxygen is required for the post-translational maturation of the protein, mature GFPs are found in corals where hyperoxia and reactive oxygen species (ROS) occur due to the photosynthetic activity of algal symbionts. In vitro spin trapping electron paramagnetic resonance and spectrophotometric assays of superoxide dismutase (SOD)-like enzyme activity show that wild type GFP from the hydromedusa, Aequorea victoria, quenches superoxide radicals (O2•−) and exhibits SOD-like activity by competing with cytochrome c for reaction with O2•−. When exposed to high amounts of O2•− the SOD-like activity and protein structure of GFP are altered without significant changes to the fluorescent properties of the protein. Because of the distribution of fluorescent proteins in both the epithelial and gastrodermal cells of reef-forming corals we propose that GFP, and possibly other fluorescent proteins, can provide supplementary antioxidant protection. PMID:17023114

Lithium Superoxide Hydrolysis and Relevance to Li–O 2 Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Hsien -Hau; Lee, Yun Jung; Assary, Rajeev S.

Fundamental understanding of reactions of lithium peroxides and superoxides is essential for the development of Li–O 2 batteries. In this context, an investigation is reported of the hydrolysis of lithium superoxide, which has recently been synthesized in a Li–O 2 battery. Surprisingly, the hydrolysis of solid LiO 2 is significantly different from that of NaO 2 and KO 2. Unlike KO 2 and NaO 2, the hydrolysis of LiO 2 does not produce H 2O 2. Similarly, the reactivity of Li 2O 2 toward water differs from LiO 2, in that Li 2O 2 results in H 2O 2 asmore » a product. The difference in the LiO 2 reactivity with water is due to the more exothermic nature of the formation of LiOH and O 2 compared with the corresponding reactions of NaO 2 and KO 2. Here, we also show that a titration method used in this study, based on reaction of the discharge product with a Ti(IV)OSO 4 solution, provides a useful diagnostic technique to provide information on the composition of a discharge product in a Li–O 2 battery.« less

Cholic acid modified N-(2-hydroxy)-propyl-3-trimethylammonium chitosan chloride for superoxide dismutase delivery.

PubMed

Cheng, Ye; Cai, Huanxin; Yin, Baoru; Yao, Ping

2013-09-15

A series of novel amphiphilic chitosan derivatives, cholic acid modified N-(2-hydroxy)-propyl-3-trimethylammonium chitosan chloride (HTCC-CA) with different quaternization degrees and cholic acid substitutions were synthesized in this study. HTCC-CA is biocompatible and forms particles in aqueous solution. The binding with superoxide dismutase (SOD) at pH 6.8 destroys the original aggregates of HTCC-CA and produces smaller SOD/HTCC-CA complex nanoparticles via electrostatic and hydrophobic interactions. The SOD loading efficiency and loading capacity of HTCC-CA can reach to more than 90% and 45%, respectively. Confocal laser scanning microscopy observation and flow cytometry analysis reveal that SOD/HTCC-CA complex nanoparticles greatly enhance the cellular internalization of the loaded SOD. The SOD activities and malonaldehyde concentrations in the serum and organs of the rats, administrated intravenously with free SOD, free HTCC-CA, and SOD/HTCC-CA nanoparticles, were assayed to evaluate the antioxidant efficiency in vivo. The results demonstrate that free HTCC-CA is effective to scavenge superoxide radicals in the blood circulation and SOD/HTCC-CA nanoparticles have better antioxidant efficiency than free SOD as well as free HTCC-CA. Copyright © 2013 Elsevier B.V. All rights reserved.

Free radical scavengers and antioxidants from Lemongrass (Cymbopogon citratus (DC.) Stapf.).

PubMed

Cheel, José; Theoduloz, Cristina; Rodríguez, Jaime; Schmeda-Hirschmann, Guillermo

2005-04-06

Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 microg/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 microg/mL and were inactive toward the XO at 50 microg/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2' '-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC(50): 9-10 microM) and inhibited lipid peroxidation by 70% at 100 microg/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC(50) values of 68.8 and 54.2 microM, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 microg/mL.

Superoxide anions produced by Streptococcus pyogenes group A-stimulated keratinocytes are responsible for cellular necrosis and bacterial growth inhibition.

PubMed

Regnier, Elodie; Grange, Philippe A; Ollagnier, Guillaume; Crickx, Etienne; Elie, Laetitia; Chouzenoux, Sandrine; Weill, Bernard; Plainvert, Céline; Poyart, Claire; Batteux, Frédéric; Dupin, Nicolas

2016-02-01

Gram-positive Streptococcus pyogenes (group A Streptococcus or GAS) is a major skin pathogen and interacts with keratinocytes in cutaneous tissues. GAS can cause diverse suppurative and inflammatory infections, such as cellulitis, a common acute bacterial dermo-hypodermitis with a high morbidity. Bacterial isolation yields from the lesions are low despite the strong local inflammation observed, raising numerous questions about the pathogenesis of the infection. Using an in vitro model of GAS-infected keratinocytes, we show that the major ROS produced is the superoxide anion ([Formula: see text]), and that its production is time- and dose-dependent. Using specific modulators of ROS production, we show that [Formula: see text] is mainly synthesized by the cytoplasmic NADPH oxidase. Superoxide anion production leads to keratinocyte necrosis but incomplete inhibition of GAS growth, suggesting that GAS may be partially resistant to the oxidative burst. In conclusion, GAS-stimulated keratinocytes are able to develop an innate immune response based on the production of ROS. This local immune response limits GAS development and induces keratinocyte cell death, resulting in the skin lesions observed in patients with cellulitis. © The Author(s) 2015.

Cell metabolic changes of porphyrins and superoxide anions by anthracene and benzo(a)pyrene.

PubMed

Uribe-Hernández, Raúl; Pérez-Zapata, Aura J; Vega-Barrita, María L; Ramón-Gallegos, Eva; Amezcua-Allieri, Myriam A

2008-09-01

The aim of this work was to evaluate the induction of protoporphyrins IX (PpIX) activity and superoxide anions (SO) in human leukocytes exposed to anthracene (ANT) and benzo(a)pyrene (B(a)P). The leukocyte LC(50)s for both hydrocarbons and the PpIX accumulation and SO overproduction were measured. The LC(50)s were 0.35 and 3.23μM for ANT and B(a)P, respectively. A linear relationship (r=0.97, p<0.01) between PpIX and ANT concentration was obtained. The induced accumulation of PpIX was proportional (r=0.63, p<0.01) to B(a)P concentration. SO overproduction showed a linear relationship (r=0.83, p<0.05) with ANT concentrations. The linear regression analysis of the effect of B(a)P on the superoxide anion overproduction showed a good coefficient (r=0.97, p<0.01), showed that ANT and B(a)P exposure induces PpIX accumulation, probably by disruption of the haem biosynthesis. ANT and B(a)P induce SO overproduction, perhaps through a process of redox cycling. Copyright © 2008 Elsevier B.V. All rights reserved.

A thermostable manganese-containing superoxide dismutase from the thermophilic fungus Thermomyces lanuginosus.

PubMed

Li, Duo-Chuan; Gao, Jing; Li, Ya-Ling; Lu, Jing

2005-02-01

A thermostable superoxide dismutase (SOD) from a Thermomyces lanuginosus strain (P134) was purified to homogeneity by fractional ammonium sulfate precipitation, ion-exchange chromatography on DEAE-Sepharose, Phenyl-Sepharose hydrophobic interaction chromatography, and gel filtration on Sephacryl S-100. The molecular mass of a single band of the enzyme was estimated to be 22.4 kDa, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Using gel filtration on Sephacryl S-100, the molecular mass was estimated to be 89.1 kDa, indicating that this enzyme was composed of four identical subunits of 22.4 kDa each. The SOD was found to be inhibited by NaN3, but not by KCN or H2O2, suggesting that the SOD in T. lanuginosus was of the manganese superoxide dismutase type. The SOD exhibited maximal activity at pH 7.5. The optimum temperature for the activity was 55 degrees C. It was thermostable at 50 and 60 degrees C and retained 55% activity after 60 min at 70 degrees C. The half-life of the SOD at 80 degrees C was approximately 28 min and even retained 20% activity after 20 min at 90 degrees C.

Radical Scavenging Activities of Tannin Extracted from Amaranth (Amaranthus caudatus L.).

PubMed

Jo, Hyeon-Ju; Chung, Kang-Hyun; Yoon, Jin A; Lee, Kwon-Jai; Song, Byeong Chun; An, Jeung Hee

2015-06-01

This study investigates the bioactivity of tannin from amaranth (Amaranthus caudatus L.) extracts. The antioxidant activities of the extracts from amaranth leaves, flowers, and seeds were evaluated. Tannin from leaves of amaranth has been evaluated for superoxide scavenging activity by using DPPH and ABTS(+) analysis, reducing power, protective effect against H2O2-induced oxidative damage in L-132 and BNL-CL2 cells, and inhibition of superoxide radical effects on HL-60 cells. At a concentration of 100 μg/ml, tannin showed protective effects and restored cell survival to 69.2% and 41.8% for L-132 and BNL-CL2 cells, respectively. Furthermore, at the same concentration, tannin inhibited 41% of the activity of the superoxide radical on HL-60 cells and 43.4% of the increase in nitric oxide levels in RAW 264.7 cells. The expression levels of the antioxidant-associated protein SOD-1 were significantly increased in a concentration-dependent manner in RAW 264.7 cells treated with tannin from amaranth leaves. These results suggest that tannin from the leaves of Amaranthus caudatus L. is a promising source of antioxidant component that can be used as a food preservative or nutraceutical.

Antiproliferative effects of mitochondria-targeted cationic antioxidants and analogs: Role of mitochondrial bioenergetics and energy-sensing mechanism

PubMed Central

Cheng, Gang; Zielonka, Jacek; McAllister, Donna; Hardy, Micael; Ouari, Olivier; Joseph, Joy; Dwinell, Michael B.; Kalyanaraman, Balaraman

2015-01-01

One of the proposed mechanisms for tumor proliferation involves redox signaling mediated by reactive oxygen species such as superoxide and hydrogen peroxide generated at moderate levels. Thus, the antiproliferative and anti-tumor effects of certain antioxidants were attributed to their ability to mitigate intracellular reactive oxygen species (ROS). Recent reports support a role for mitochondrial ROS in stimulating tumor cell proliferation. In this study, we compared the antiproliferative effects and the effects on mitochondrial bioenergetic functions of a mitochondria-targeted cationic carboxyproxyl nitroxide (Mito-CP), exhibiting superoxide dismutase (SOD)-like activity and a synthetic cationic acetamide analog (Mito-CP-Ac) lacking the nitroxide moiety responsible for the SOD activity. Results indicate that both Mito-CP and Mito-CP-Ac potently inhibited tumor cell proliferation. Both compounds altered mitochondrial and glycolytic functions, and intracellular citrate levels. Both Mito-CP and Mito-CP-Ac synergized with 2-deoxy-glucose (2-DG) to deplete intracellular ATP, inhibit cell proliferation and induce apoptosis in pancreatic cancer cells. We conclude that mitochondria-targeted cationic agents inhibit tumor proliferation via modification of mitochondrial bioenergetics pathways rather than by dismutating and detoxifying mitochondrial superoxide. PMID:26004344

Redesigning the blue copper azurin into a redox-active mononuclear nonheme iron protein: preparation and study of Fe(II)-M121E azurin.

PubMed

Liu, Jing; Meier, Katlyn K; Tian, Shiliang; Zhang, Jun-Long; Guo, Hongchao; Schulz, Charles E; Robinson, Howard; Nilges, Mark J; Münck, Eckard; Lu, Yi

2014-09-03

Much progress has been made in designing heme and dinuclear nonheme iron enzymes. In contrast, engineering mononuclear nonheme iron enzymes is lagging, even though these enzymes belong to a large class that catalyzes quite diverse reactions. Herein we report spectroscopic and X-ray crystallographic studies of Fe(II)-M121E azurin (Az), by replacing the axial Met121 and Cu(II) in wild-type azurin (wtAz) with Glu and Fe(II), respectively. In contrast to the redox inactive Fe(II)-wtAz, the Fe(II)-M121EAz mutant can be readily oxidized by Na2IrCl6, and interestingly, the protein exhibits superoxide scavenging activity. Mössbauer and EPR spectroscopies, along with X-ray structural comparisons, revealed similarities and differences between Fe(II)-M121EAz, Fe(II)-wtAz, and superoxide reductase (SOR) and allowed design of the second generation mutant, Fe(II)-M121EM44KAz, that exhibits increased superoxide scavenging activity by 2 orders of magnitude. This finding demonstrates the importance of noncovalent secondary coordination sphere interactions in fine-tuning enzymatic activity.

Consequences of age on ischemic wound healing in rats: altered antioxidant activity and delayed wound closure.

PubMed

Moor, Andrea N; Tummel, Evan; Prather, Jamie L; Jung, Michelle; Lopez, Jonathan J; Connors, Sarah; Gould, Lisa J

2014-04-01

Advertisements targeted at the elderly population suggest that antioxidant therapy will reduce free radicals and promote wound healing, yet few scientific studies substantiate these claims. To better understand the potential utility of supplemental antioxidant therapy for wound healing, we tested the hypothesis that age and tissue ischemia alter the balance of endogenous antioxidant enzymes. Using a bipedicled skin flap model, ischemic and non-ischemic wounds were created on young and aged rats. Wound closure and the balance of the critical antioxidants superoxide dismutase and glutathione in the wound bed were determined. Ischemia delayed wound closure significantly more in aged rats. Lower superoxide dismutase 2 and glutathione in non-ischemic wounds of aged rats indicate a basal deficit due to age alone. Ischemic wounds from aged rats had lower superoxide dismutase 2 protein and activity initially, coupled with decreased ratios of reduced/oxidized glutathione and lower glutathione peroxidase activity. De novo glutathione synthesis, to restore redox balance in aged ischemic wounds, was initiated as evidenced by increased glutamate cysteine ligase. Results demonstrate deficiencies in two antioxidant pathways in aged rats that become exaggerated in ischemic tissue, culminating in profoundly impaired wound healing and prolonged inflammation.

Cellular detection of 50 Hz magnetic fields and weak blue light: effects on superoxide levels and genotoxicity.

PubMed

Höytö, Anne; Herrala, Mikko; Luukkonen, Jukka; Juutilainen, Jukka; Naarala, Jonne

2017-06-01

We tested the hypothesis that the effects of 50 Hz magnetic fields (MFs) on superoxide levels and genotoxicity depend on the presence of blue light. Human SH-SY5Y neuroblastoma cells were exposed to a 50 Hz, 100 μT MF with or without non-phototoxic level of blue light for 24 h. We also studied whether these treatments alter responses to menadione, an agent that induces mitochondrial superoxide (O 2 • - ) production and DNA damage. Micronuclei, proliferation, viability, cytosolic and mitochondrial O 2 • - levels were assessed. MF (without blue light) increased cytosolic O 2 • - production and blue light suppressed this effect. Mitochondrial O 2 • - production was reduced by both MF and blue light, but these effects were not additive. Micronucleus frequency was not affected by blue light or MF alone, but blue light (significantly when combined with MF) enhanced menadione-induced micronuclei. The original simple hypothesis (blue light is needed for MF effects) was not supported, but interaction of MF and blue light was nevertheless observed. The results are consistent with MF effects on light-independent radical reactions.

Effect of catalase inactivation on levels of inorganic peroxides, superoxide dismutase, glutathione, oxygen consumption and life span in adult houseflies (Musca domestica).

PubMed Central

Allen, R G; Farmer, K J; Sohal, R S

1983-01-01

The effects of total inhibition of catalase, induced by 3-amino-1,2,4-triazole, on the adult housefly (Musca domestica) were examined. The lack of catalase activity had no effect on the longevity of the houseflies. Inorganic-peroxide concentration was elevated at younger ages, but declined in older flies. The rate of oxygen consumption by the flies was greatly decreased and the levels of oxidized as well as reduced glutathione were augmented. Superoxide dismutase activity showed a slight increase. This study suggests that loss of catalase activity does not affect survival of houseflies due to adaptive responses. PMID:6661212

Production and removal of superoxide anion radical by artificial metalloenzymes and redox-active metals

PubMed Central

Kawano, Tomonori; Kagenishi, Tomoko; Kadono, Takashi; Bouteau, François; Hiramatsu, Takuya; Lin, Cun; Tanaka, Kenichiro; Tanaka, Licca; Mancuso, Stefano; Uezu, Kazuya; Okobira, Tadashi; Furukawa, Hiroka; Iwase, Junichiro; Inokuchi, Reina; Baluška, Frantisek; Yokawa, Ken

2015-01-01

Generation of reactive oxygen species is useful for various medical, engineering and agricultural purposes. These include clinical modulation of immunological mechanism, enhanced degradation of organic compounds released to the environments, removal of microorganisms for the hygienic purpose, and agricultural pest control; both directly acting against pathogenic microorganisms and indirectly via stimulation of plant defense mechanism represented by systemic acquired resistance and hypersensitive response. By aiming to develop a novel classes of artificial redox-active biocatalysts involved in production and/or removal of superoxide anion radicals, recent attempts for understanding and modification of natural catalytic proteins and functional DNA sequences of mammalian and plant origins are covered in this review article. PMID:27066179

NQO2 Is a Reactive Oxygen Species Generating Off-Target for Acetaminophen

PubMed Central

2014-01-01

The analgesic and antipyretic compound acetaminophen (paracetamol) is one of the most used drugs worldwide. Acetaminophen overdose is also the most common cause for acute liver toxicity. Here we show that acetaminophen and many structurally related compounds bind quinone reductase 2 (NQO2) in vitro and in live cells, establishing NQO2 as a novel off-target. NQO2 modulates the levels of acetaminophen derived reactive oxygen species, more specifically superoxide anions, in cultured cells. In humans, NQO2 is highly expressed in liver and kidney, the main sites of acetaminophen toxicity. We suggest that NQO2 mediated superoxide production may function as a novel mechanism augmenting acetaminophen toxicity. PMID:25313982

E.s.r., magnetic, optical and biological (SOD and antimicrobial) studies of imidazolate bridged Cu II-Zn II and Cu II-Ni II complexes with tris(2-amino ethyl)amine as capping ligand: a plausible model for superoxide dismutase

NASA Astrophysics Data System (ADS)

Singh, Nripendra; Shukla, K. K.; Patel, R. N.; Chauhan, U. K.; Shrivastava, R.

2003-11-01

X-band e.s.r. and optical absorption spectra of the imidazolate bridged heterobimetallic complexes [(tren)Cu-E-Im-Zn-(tren)](ClO 4) 3 and [(tren)Cu-E-Im-Ni-(tren)](ClO 4) 3, where trentris(2-aminoethyl)amine, E-Im=2-ethylimidazolate ion and the related mononuclear complexes [Cu(tren)](ClO 4) 2 and [(tren)Cu-E-ImH)](ClO 4) 2 have been described. Biological activities (superoxide dismutase and antimicrobial) have also been measured and compared with reported complexes.

Blueberry extracts protect testis from hypobaric hypoxia induced oxidative stress in rats.

PubMed

Zepeda, Andrea; Aguayo, Luis G; Fuentealba, Jorge; Figueroa, Carolina; Acevedo, Alejandro; Salgado, Perla; Calaf, Gloria M; Farías, Jorge

2012-01-01

Exposure to hypobaric hypoxia causes oxidative damage to male rat reproductive function. The aim of this study was to evaluate the protective effect of a blueberry extract (BB-4) in testis of rats exposed to hypobaric hypoxia. Morphometric analysis, cellular DNA fragmentation, glutathione reductase (GR), and superoxide dismutase (SOD) activities were evaluated. Our results showed that supplementation of BB-4 reduced lipid peroxidation, decreased apoptosis, and increased GR and SOD activities in rat testis under hypobaric hypoxia conditions (P < 0.05). Therefore, this study demonstrates that blueberry extract significantly reduced the harmful effects of oxidative stress caused by hypobaric hypoxia in rat testis by affecting glutathione reductase and superoxide dismutase activities.

Investigation of the simultaneous production of superoxide dismutase and catalase enzymes from Rhodotorula glutinis under different culture conditions.

PubMed

Unlü, Ayşe Ezgi; Takaç, Serpil

2012-10-01

The simultaneous production production of superoxide (SOD) and catalase (CAT) from Rhodotorula glutinis was studied. The effects of temperature, initial medium pH, and carbon source on the enzyme activities were investigated. Temperature and carbon sources were found to have significant effects on the enzyme activities. 10°C provided the highest specific CAT and SOD activities as 22.6 U/mg protein and 170 U/mg protein, respectively. Glycerol was found to be the best carbon source for enzyme activities, providing 113 U/mg protein for CAT and 125 U/mg protein for SOD, which were also the highest activities obtained in the present study.

Super-oxidation of silicon nanoclusters: magnetism and reactive oxygen species at the surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lepeshkin, Sergey; Baturin, Vladimir; Tikhonov, Evgeny

2016-01-01

Oxidation of silicon nanoclusters depending on the temperature and oxygen pressure is explored from first principles using the evolutionary algorithm, and structural and thermodynamic analysis. From our calculations of 90 SinOm clusters we found that under normal conditions oxidation does not stop at the stoichiometric SiO2 composition, as it does in bulk silicon, but goes further placing extra oxygen atoms on the cluster surface. These extra atoms are responsible for light emission, relevant to reactive oxygen species and many of them are magnetic. We argue that the super-oxidation effect is size-independent and discuss its relevance to nanotechnology and miscellaneous applications,more » including biomedical ones.« less

Mechanism of oxygen electroreduction on gold surfaces in basic media.

PubMed

Kim, Jongwon; Gewirth, Andrew A

2006-02-16

The mechanism of the electroreduction of oxygen on Au surfaces in basic media is examined using surface-enhanced Raman scattering (SERS) measurements and density functional theory (DFT) calculations. The spectroscopy reveals superoxide species as a reduction intermediate throughout the oxygen electroreduction, while no peroxide is detected. The spectroscopy also shows the presence of superoxide after the addition of hydrogen peroxide. The calculations show no effect of OH addition to the Au(100) surface with regard to O-O length. These results suggest that the four-electron reduction of O(2) on Au(100) in base arises from a disproportionation mechanism which is enhanced on Au(100) relative to the other two low Miller index faces of Au.

Protection against hyperoxia by serum from endotoxin treated rats: absence of superoxide dismutase induction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berg, J.T.; Smith, R.M.

Endotoxin greatly reduces lung injury and pleural effusions in adult rats exposed to normobaric hyperoxia (> 98% oxygen for 60 hours). This study reports that serum from endotoxin treated donor rats protects serum recipients against hyperoxic lung injury without altering lung superoxide dismutase (SOD) activity. Rats pretreated with endotoxin alone were protected and exhibited an increase in lung SOD activity as previously reported by others. Protection by serum was not due to the transfer of residual endotoxin or SOD. These results show, that protection from oxygen toxicity can occur in rats without an increase in lung SOD and suggest thatmore » a serum factor may be involved.« less

High-sensitivity imaging method of singlet oxygen and superoxide anion in photodynamic and sonodynamic actions

NASA Astrophysics Data System (ADS)

Xing, Da; He, Yonghong; Hao, Min; Chen, Qun

2004-07-01

A novel method of photodynamic diagnosis (PDD) of cancer mediated by chemiluminescence (CL) probe is presented. The mechanism for photodynamic therapy (PDT) involves reactive oxygen species (ROS), such as singlet oxygen (1O2) and superoxide (O2-), generated by during the photochemical process. Both 1O2 and O2- can react with Cypridina luciferin analogue (FCLA), a highly selective CL probe for detecting the ROS. Chemiluminescence from the reaction of FCLA with the ROS, at about 530 nm, was detected by a highly sensitive ICCD system. The CL was markedly inhibited by the addition of 10 mmol/L sodium azide (NaN3) in a sample solution. Similar phenomena, with lesser extents of changes, were observed at the additions of 10 μmol/L superoxide dismutase (SOD), 10 mmol/L mannitol, and 100 μg/mL catalase, respectively. This indicates that the detected CL signals were mainly from ROS generated during the photosensitization reactions. Also, the chemiluminescence method was used to detect the ROS during sonodynamic action, both in vitro and in vivo. ROS formation during sonosensitizations of HpD and ATX-70 were detected using our newly-developed imaging technique, in real time, on tumor bearing animals. This method can provide a new means in clinics for tumor diagnosis.

Identification of biomarkers for the antiangiogenic and antitumour activity of the superoxide dismutase 1 (SOD1) inhibitor tetrathiomolybdate (ATN-224)

PubMed Central

Doñate, F; Juarez, J C; Burnett, M E; Manuia, M M; Guan, X; Shaw, D E; Smith, E L P; Timucin, C; Braunstein, M J; Batuman, O A; Mazar, A P

2008-01-01

Tetrathiomolybdate (choline salt; ATN-224), a specific, high-affinity copper binder, is currently being evaluated in several phase II cancer trials. ATN-224 inhibits CuZn superoxide dismutase 1 (SOD1) leading to antiangiogenic and antitumour effects. The pharmacodynamics of tetrathiomolybdate has been followed by tracking ceruloplasmin (Cp), a biomarker for systemic copper. However, at least in mice, the inhibition of angiogenesis occurs before a measurable decrease in systemic copper is observed. Thus, the identification and characterisation of other biomarkers to follow the activity of ATN-224 in the clinic is of great interest. Here, we present the preclinical evaluation of two potential biomarkers for the activity of ATN-224: (i) SOD activity measurements in blood cells in mice and (ii) levels of endothelial progenitor cells (EPCs) in bonnet macaques treated with ATN-224. The superoxide dismutase activity in blood cells in mice is rapidly inhibited by ATN-224 treatment at doses at which angiogenesis is maximally inhibited. Furthermore, ATN-224 dosing in bonnet macaques causes a profound and reversible decrease in EPCs without significant toxicity. Thus, both SOD activity measurements and levels of EPCs may be useful biomarkers of the antiangiogenic activity of ATN-224 to be used in its clinical development. PMID:18253124

Molecular and biochemical characterization of a unique mutation in CCS, the human copper chaperone to superoxide dismutase.

PubMed

Huppke, Peter; Brendel, Cornelia; Korenke, Georg Christoph; Marquardt, Iris; Donsante, Anthony; Yi, Ling; Hicks, Julia D; Steinbach, Peter J; Wilson, Callum; Elpeleg, Orly; Møller, Lisbeth Birk; Christodoulou, John; Kaler, Stephen G; Gärtner, Jutta

2012-08-01

Copper (Cu) is a trace metal that readily gains and donates electrons, a property that renders it desirable as an enzyme cofactor but dangerous as a source of free radicals. To regulate cellular Cu metabolism, an elaborate system of chaperones and transporters has evolved, although no human Cu chaperone mutations have been described to date. We describe a child from a consanguineous family who inherited homozygous mutations in the SLC33A1, encoding an acetyl CoA transporter, and in CCS, encoding the Cu chaperone for superoxide dismutase. The CCS mutation, p.Arg163Trp, predicts substitution of a highly conserved arginine residue at position 163, with tryptophan in domain II of CCS, which interacts directly with superoxide dismutase 1 (SOD1). Biochemical analyses of the patient's fibroblasts, mammalian cell transfections, immunoprecipitation assays, and Lys7Δ (CCS homolog) yeast complementation support the pathogenicity of the mutation. Expression of CCS was reduced and binding of CCS to SOD1 impaired. As a result, this mutation causes reduced SOD1 activity and may impair other mechanisms important for normal Cu homeostasis. CCS-Arg163Trp represents the primary example of a human mutation in a gene coding for a Cu chaperone. © 2012 Wiley Periodicals, Inc.

Ultra Fine Particles from Diesel Engines Induce Vascular Oxidative Stress via JNK Activation

PubMed Central

Li, Rongsong; Ning, Zhi; Cui, Jeffery; Khalsa, Bhavraj; Ai, Lisong; Takabe, Wakako; Beebe, Tyler; Majumdar, Rohit; Sioutas, Constantinos; Hsiai, Tzung

2011-01-01

Exposure of particulate air pollution is linked to increased incidences of cardiovascular diseases. Ambient ultra fine particles (UFP) from diesel vehicle engines have been shown to be pro-atherogenic in apoE knockout mice and may constitute a major cardiovascular risk in humans. We posited that circulating nano-sized particles from traffic pollution sources induced vascular oxidative stress via JNK activation in endothelial cells. Diesel UFP were collected from a 1998 Kenworth truck. Intra-cellular superoxide assay revealed that these UFP dose-dependently induced superoxide (O2·-) production in human aortic endothelial cells (HAEC). Flow cytometry (FACS) showed that UFP increased MitoSOX Red intensity specific for mitochondrial superoxide. Protein carbonyl content is increased by UFP as an indication of vascular oxidative stress. UFP also up-regulated hemeoxygenase-1 (HO-1) and tissue factor (TF) mRNA expression, and pre-treatment with antioxidant, N-acetyl cysteine (NAC), significantly decreased their expression. Furthermore, UFP transiently activated JNK in HAEC. Treatment with JNK inhibitor SP600125 and silencing of both JNK1 and JNK2 with siRNA inhibited UFP stimulated O2·- production and mRNA expression of HO-1 and TF. Our findings suggest that JNK activation play an important role in UFP-induced oxidative stress and stress response gene expression. PMID:19154785

Rapid reaction of nanomolar Mn(II) with superoxide radical in seawater and simulated freshwater

USGS Publications Warehouse

Hansard, S.P.; Easter, H.D.; Voelker, Bettina M.

2011-01-01

Superoxide radical (O2-) has been proposed to be an important participant in oxidation-reduction reactions of metal ions in natural waters. Here, we studied the reaction of nanomolar Mn(II) with O 2- in seawater and simulated freshwater, using chemiluminescence detection of O2- to quantify the effect of Mn(II) on the decay kinetics of O2-. With 3-24 nM added [Mn(II)] and <0.7 nM [O2-], we observed effective second-order rate constants for the reaction of Mn(II) with O2- of 6 ?? 106 to 1 ?? 107 M -1???s-1 in various seawater samples. In simulated freshwater (pH 8.6), the effective rate constant of Mn(II) reaction with O 2- was somewhat lower, 1.6 ?? 106 M -1???s-1. With higher initial [O2-], in excess of added [Mn(II)], catalytic decay of O 2- by Mn was observed, implying that a Mn(II/III) redox cycle occurred. Our results show that reactions with nanomolar Mn(II) could be an important sink of O2- in natural waters. In addition, reaction of Mn(II) with superoxide could maintain a significant fraction of dissolved Mn in the +III oxidation state. ?? 2011 American Chemical Society.

Increased mitochondrial matrix directed superoxide production by fatty acid hydroperoxides in skeletal muscle mitochondria

PubMed Central

Bhattacharya, Arunabh; Lustgarten, Michael; Shi, Yun; Liu, Yuhong; Jang, Youngmok C; Pulliam, Daniel; Jernigan, Amanda L; Van Remmen, Holly

2013-01-01

Previous studies have shown that muscle atrophy is associated with mitochondrial dysfunction and an increased rate of mitochondrial reactive oxygen species production. We recently demonstrated that fatty acid hydroperoxides (FA-OOH) are significantly elevated in mitochondria isolated from atrophied muscles. The purpose of the current study is to determine whether FA-OOH can alter skeletal muscle mitochondrial function. We found that FA-OOH (at low micromolar concentrations) induces mitochondrial dysfunction assessed by decrease in the rate of ATP production, oxygen consumption and activity of respiratory chain complexes I and III. Using methods to distinguish superoxide release towards the matrix and inter-membrane space, we demonstrate that FA-OOH significantly elevates oxidative stress in the mitochondrial matrix (and not the inter-membrane space) with complex I as the major site of superoxide production (most likely from a site upstream of the ubiquinone binding site but downstream from the flavin binding site-the iron sulfur clusters). Our results are the first to indicate that FA-OOH’s are important modulators of mitochondrial function and oxidative stress in skeletal muscle mitochondria and may play an important role in muscle atrophies that are associated with increased generation of FA-OOH’s, e.g., denervation-induced muscle atrophy. PMID:21172427

[Resistance of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ to reactive oxygen species].

PubMed

Zhang, Shuwen; Lv, Jiaping; Menghe, Bilige; Zhang, Heping; Zhang, Liyu; Song, Jinhui; Wang, Zhifei

2009-02-01

We evaluated antioxidative effect of two antioxidative strains, isolated from the traditional fermented dairy products. Both intact cells and cell-free extract of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ were used to study the inhibited effect of linoleic acid peroxidation, the ability of scavenging 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, superoxide anion radical,the ability of tolerancing hydrogen peroxide and the chelating capacity of ferrous ion and reducting activity. Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ demonstrated highest inhibition on linoleic acid peroxidation by 62.95% and 66.16%, respectively. The cell-free extract showed excellent scavenging superoxide anion and hydroxyl radicals activity. However, the intact cells of Lactobacillus delbrueckii subsp. bulgaricus LJJ scavenging superoxide and hydroxyl radicals capacity were not detected. The intact cells of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ on 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability and chelating ferrous ion capacity were superior to cell-free extract. The highest reduced activety was equivalent to 305 micromol/L and 294 micromol/L L-cysteine. Two latobacilli strains had good antioxidant capacity. As potential probiotics, it can be used in future.

[Accelerated senescence of fresh-cut Chinese water chestnut tissues in relation to hydrogen peroxide accumulation].

PubMed

Peng, Li-Tao; Jiang, Yue-Ming; Yang, Shu-Zhen; Pan, Si-Yi

2005-10-01

Accelerated senescence of fresh-cut Chinese water chestnut (CWC) tissues in relation to active oxygen species (AOS) metabolism was investigated. Fresh-cut CWC (2 mm thick) and intact CWC were stored at 4 degrees C in trays wrapped with plastic films. Changes in superoxide anion production rate, activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were monitored, while contents of hydrogen peroxide, ascorbic acid, MDA as well as electrolyte leakage were measured. Fresh-cutting of CWC induced activities of SOD, CAT and APX to a certain extent (Fig. 2B and Fig. 3), but simultaneously stimulated superoxide anion production markedly (Fig. 2A), enhanced hydrogen peroxide accumulation and accelerated loss in ascorbic acid (Figs. 4 and 5), which resulted in increased lipid peroxidation indicated by malondialdehyde (MDA) content and electrolyte leakage (Fig. 1). Statistics analysis indicated that there was a significantly positive correlation among hydrogen peroxide accumulation, MDA content and electrolyte leakage (Table 1). Histochemical detection with 3, 3'-diaminobenzidine further demonstrated that hydrogen peroxide accumulation increased in fresh-cut CWC during storage (Fig. 5). AOS production rate and activities of SOD, CAT and APX changed little while no obvious hydrogen peroxide accumulation was observed, in intact CWC during storage.

Increased survival of skin flaps by scavengers of superoxide radical

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, L.; Privalle, C.T.; Serafin, D.

1987-08-01

Elevation of rat abdominal skin flaps, followed by ligation and division of the left inferior neurovascular pedicle, resulted in only a 40% survival of the area normally perfused by the ligated artery and vein. Superoxide dismutase (SOD) (EC1.15.1.1) administered v (20,000 U/kg) 30 min before flap elevation increased survival to 52%. SOD derivatized with polyethylene gycol, which increases circulating half-life, was more effective, increasing survival to 80%. This protective effect resulted from the catalytic activity of the derivatized enzyme because inactivation by treatment with H/sub 2/O/sub 2/ eliminated its effect on skin flap survival. An equimolar mixture of Desferal andmore » MnCl/sub 2/, which catalyzes the dismutation of O/sub 2//sup -/ in vitro, improved survival to 72%. Desferal-Fe/sup 3 +/, which lacks in vitro SOD activity, or Mn/sup 2 +/ alone did not affect the survival of skin flaps, but Desferal alone was nearly as effective as the Desferal-Mn/sup 2 +/ mixture. This effect of Desferal may result from acquisition of and subsequent removal of iron in vivo. These results support the view that the superoxide radical or a product derived from it plays a role in limiting the survival of island skin flaps.« less

Metal bacteriochlorins which act as dual singlet oxygen and superoxide generators.

PubMed

Fukuzumi, Shunichi; Ohkubo, Kei; Zheng, Xiang; Chen, Yihui; Pandey, Ravindra K; Zhan, Riqiang; Kadish, Karl M

2008-03-06

A series of stable free-base, Zn(II) and Pd(II) bacteriochlorins containing a fused six- or five-member diketo- or imide ring have been synthesized as good candidates for photodynamic therapy sensitizers, and their electrochemical, photophysical, and photochemical properties were examined. Photoexcitation of the palladium bacteriochlorin affords the triplet excited state without fluorescence emission, resulting in formation of singlet oxygen with a high quantum yield due to the heavy atom effect of palladium. Electrochemical studies revealed that the zinc bacteriochlorin has the smallest HOMO-LUMO gap of the investigated compounds, and this value is significantly lower than the triplet excited-state energy of the compound in benzonitrile. Such a small HOMO-LUMO gap of the zinc bacteriochlorin enables intermolecular photoinduced electron transfer from the triplet excited state to the ground state to produce both the radical cation and the radical anion. The radical anion thus produced can transfer an electron to molecular oxygen to produce superoxide anion which was detected by electron spin resonance. The same photosensitizer can also act as an efficient singlet oxygen generator. Thus, the same zinc bacteriochlorin can function as a sensitizer with a dual role in that it produces both singlet oxygen and superoxide anion in an aprotic solvent (benzonitrile).

A Suppressor of the Menadione-Hypersensitive Phenotype of a Xanthomonas campestris pv. phaseoli oxyR Mutant Reveals a Novel Mechanism of Toxicity and the Protective Role of Alkyl Hydroperoxide Reductase

PubMed Central

Vattanaviboon, Paiboon; Whangsuk, Wirongrong; Mongkolsuk, Skorn

2003-01-01

We isolated menadione-resistant mutants of Xanthomonas campestris pv. phaseoli oxyR (oxyRXp). The oxyRR2Xp mutant was hyperresistant to the superoxide generators menadione and plumbagin and was moderately resistant to H2O2 and tert-butyl hydroperoxide. Analysis of enzymes involved in oxidative-stress protection in the oxyRR2Xp mutant revealed a >10-fold increase in AhpC and AhpF levels, while the levels of superoxide dismutase (SOD), catalase, and the organic hydroperoxide resistance protein (Ohr) were not significantly altered. Inactivation of ahpC in the oxyRR2Xp mutant resulted in increased sensitivity to menadione killing. Moreover, high levels of expression of cloned ahpC and ahpF in the oxyRXp mutant complemented the menadione hypersensitivity phenotype. High levels of other oxidant-scavenging enzymes such as catalase and SOD did not protect the cells from menadione toxicity. These data strongly suggest that the toxicity of superoxide generators could be mediated via organic peroxide production and that alkyl hydroperoxide reductase has an important novel function in the protection against the toxicity of these compounds in X. campestris. PMID:12591894

Intramitochondrial Ascorbic Acid Enhances the Formation of Mitochondrial Superoxide Induced by Peroxynitrite via a Ca2+-Independent Mechanism

PubMed Central

Guidarelli, Andrea; Cerioni, Liana; Fiorani, Mara; Cantoni, Orazio

2017-01-01

Exposure of U937 cells to peroxynitrite promotes mitochondrial superoxide formation via a mechanism dependent on both inhibition of complex III and increased mitochondrial Ca2+ accumulation. Otherwise inactive concentrations of the oxidant produced the same maximal effects in the presence of either complex III inhibitors or agents mobilizing Ca2+ from the ryanodine receptor and enforcing its mitochondrial accumulation. l-Ascorbic acid (AA) produced similar enhancing effects in terms of superoxide formation, DNA strand scission and cytotoxicity. However, AA failed to enhance the intra-mitochondrial concentration of Ca2+ and the effects observed in cells supplemented with peroxinitrite, while insensitive to manipulations preventing the mobilization of Ca2+, or the mitochondrial accumulation of the cation, were also detected in human monocytes and macrophages, which do not express the ryanodine receptor. In all these cell types, mitochondrial permeability transition-dependent toxicity was detected in cells exposed to AA/peroxynitrite and, based on the above criteria, these responses also appeared Ca2+-independent. The enhancing effects of AA are therefore similar to those mediated by bona fide complex III inhibitors, although the vitamin failed to directly inhibit complex III, and in fact enhanced its sensitivity to the inhibitory effects of peroxynitrite. PMID:28767071

Insight from first principles into the stability and magnetism of alkali-metal superoxide nanoclusters

NASA Astrophysics Data System (ADS)

Arcelus, Oier; Suaud, Nicolas; Katcho, Nebil A.; Carrasco, Javier

2017-05-01

Alkali-metal superoxides are gaining increasing interest as 2p magnetic materials for information and energy storage. Despite significant research efforts on bulk materials, gaps in our knowledge of the electronic and magnetic properties at the nanoscale still remain. Here, we focused on the role that structural details play in determining stability, electronic structure, and magnetic couplings of (MO2)n (M = Li, Na, and K, with n = 2-8) clusters. Using first-principles density functional theory based on the Perdew-Burke-Ernzerhof and Heyd-Scuseria-Ernzerhof functionals, we examined the effect of atomic structure on the relative stability of different polymorphs within each investigated cluster size. We found that small clusters prefer to form planar-ring structures, whereas non-planar geometries become more stable when increasing the cluster size. However, the crossover point depends on the nature of the alkali metal. Our analysis revealed that electrostatic interactions govern the highly ionic M-O2 bonding and ultimately control the relative stability between 2-D and 3-D geometries. In addition, we analyzed the weak magnetic couplings between superoxide molecules in (NaO2)4 clusters comparing model Hamiltonian methods based on Wannier function projections onto πg states with wave function-based multi-reference calculations.

The p53/p21(WAF/CIP) pathway mediates oxidative stress and senescence in dyskeratosis congenita cells with telomerase insufficiency.

PubMed

Westin, Erik R; Aykin-Burns, Nukhet; Buckingham, Erin M; Spitz, Douglas R; Goldman, Frederick D; Klingelhutz, Aloysius J

2011-03-15

Telomere attrition is a natural process that occurs due to inadequate telomere maintenance. Once at a critically short threshold, telomeres signal growth arrest, leading to senescence. Telomeres can be elongated by the enzyme telomerase, which adds de novo telomere repeats to the ends of chromosomes. Mutations in genes for telomere binding proteins or components of telomerase give rise to the premature aging disorder dyskeratosis congenita (DC), which is characterized by extremely short telomeres and an aging phenotype. The current study demonstrates that DC cells signal a DNA damage response through p53 and its downstream mediator, p21(WAF/CIP), which is accompanied by an elevation in steady-state levels of superoxide and percent glutathione disulfide, both indicators of oxidative stress. Poor proliferation of DC cells can be partially overcome by reducing O(2) tension from 21% to 4%. Further, restoring telomerase activity or inhibiting p53 or p21(WAF/CIP) significantly mitigated growth inhibition as well as caused a significant decrease in steady-state levels of superoxide. Our results support a model in which telomerase insufficiency in DC leads to p21(WAF/CIP) signaling, via p53, to cause increased steady-state levels of superoxide, metabolic oxidative stress, and senescence.

The water-water cycle as alternative photon and electron sinks.

PubMed

Asada, K

2000-10-29

The water-water cycle in chloroplasts is the photoreduction of dioxygen to water in photosystem I (PS I) by the electrons generated in photosystem II (PS II) from water. In the water-water cycle, the rate of photoreduction of dioxygen in PS I is several orders of magnitude lower than those of the disproportionation of superoxide catalysed by superoxide dismutase, the reduction of hydrogen peroxide to water catalysed by ascorbate peroxidase, and the reduction of the resulting oxidized forms of ascorbate by reduced ferredoxin or catalysed by either dehydroascorbate reductase or monodehydroascorbate reductase. The water-water cycle therefore effectively shortens the lifetimes of photoproduced superoxide and hydrogen peroxide to suppress the production of hydroxyl radicals, their interactions with the target molecules in chloroplasts, and resulting photoinhibition. When leaves are exposed to photon intensities of sunlight in excess of that required to support the fixation of CO2, the intersystem electron carriers are over-reduced, resulting in photoinhibition. Under such conditions, the water-water cycle not only scavenges active oxygens, but also safely dissipates excess photon energy and electrons, in addition to downregulation of PS II and photorespiration. The dual functions of the water-water cycle for protection from photoinhibition under photon excess stress are discussed, along with its functional evolution.

Role of ERK1/2 kinase in the expression of iNOS by NDMA in human neutrophils.

PubMed

Ratajczak-Wrona, Wioletta; Jablonska, Ewa; Garley, Marzena; Jablonski, Jakub; Radziwon, Piotr

2013-01-01

Potential role of ERK1/2 kinase in conjunction with p38 in the regulation of inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production, and superoxide anion generation by human neutrophils (PMNs) exposed to N-nitrosodimethylamine (NDMA) was determined. Increased synthesis of NO due to the involvement of iNOS in neutrophils exposed to NDMA was observed. In addition, intensified activation of ERK1/2 and p38 kinases was determined in these cells. Inhibition of kinase regulated by extracellular signals (ERK1/2) pathway, in contrast to p38 pathway, led to an increased production of NO and expression of iNOS in PMNs. Moreover, as a result of inhibition of ERK1/2 pathway, a decreased activation of p38 kinase was observed in neutrophils, while inhibition of p38 kinase did not affect activation of ERK1/2 pathway in these cells. An increased ability to release superoxide anion by the studied PMNs was observed, which decreased after ERK1/2 pathway inhibition. In conclusion, in human neutrophils, ERK1/2 kinase is not directly involved in the regulation of iNOS and NO production induced by NDMA; however, the kinase participates in superoxide anion production in these cells.

Alkane inducible proteins in Geobacillus thermoleovorans B23

PubMed Central

2009-01-01

Background Initial step of β-oxidation is catalyzed by acyl-CoA dehydrogenase in prokaryotes and mitochondria, while acyl-CoA oxidase primarily functions in the peroxisomes of eukaryotes. Oxidase reaction accompanies emission of toxic by-product reactive oxygen molecules including superoxide anion, and superoxide dismutase and catalase activities are essential to detoxify them in the peroxisomes. Although there is an argument about whether primitive life was born and evolved under high temperature conditions, thermophilic archaea apparently share living systems with both bacteria and eukaryotes. We hypothesized that alkane degradation pathways in thermophilic microorganisms could be premature and useful to understand their evolution. Results An extremely thermophilic and alkane degrading Geobacillus thermoleovorans B23 was previously isolated from a deep subsurface oil reservoir in Japan. In the present study, we identified novel membrane proteins (P16, P21) and superoxide dismutase (P24) whose production levels were significantly increased upon alkane degradation. Unlike other bacteria acyl-CoA oxidase and catalase activities were also increased in strain B23 by addition of alkane. Conclusion We first suggested that peroxisomal β-oxidation system exists in bacteria. This eukaryotic-type alkane degradation pathway in thermophilic bacterial cells might be a vestige of primitive living cell systems that had evolved into eukaryotes. PMID:19320977

Antioxidant effects of nerolidol in mice hippocampus after open field test.

PubMed

Nogueira Neto, José Damasceno; de Almeida, Antonia Amanda Cardoso; da Silva Oliveira, Johanssy; Dos Santos, Pauline Sousa; de Sousa, Damião Pergentino; de Freitas, Rivelilson Mendes

2013-09-01

The aim of this study was to evaluate the neuroprotective effects of nerolidol in mice hippocampus against oxidative stress in neuronal cells compared to ascorbic acid (positive control) as well as evaluated the nerolidol sedative effects by open field test compared to diazepam (positive control). Thirty minutes prior to behavioral observation on open field test, mice were intraperitoneally treated with vehicle, nerolidol (25, 50 and 75 mg/kg), diazepam (1 mg/kg) or ascorbic acid (250 mg/kg). To clarify the action mechanism of of nerolidol on oxidative stress in animals subjected to the open field test, Western blot analysis of Mn-superoxide dismutase and catalase in mice hippocampus were performed. In nerolidol group, there was a significant decrease in lipid peroxidation and nitrite levels when compared to negative control (vehicle). However, a significant increase was observed in superoxide dismutase and catalase activities in this group when compared to the other groups. Vehicle, diazepam, ascorbic acid and nerolidol groups did not affected Mn-superoxide dismutase, catalase mRNA or protein levels. Our findings strongly support the hypothesis that oxidative stress occurs in hippocampus. Nerolidol showed sedative effects in animals subjected to the open field test. Oxidative process plays a crucial role on neuronal pathological consequence, and implies that antioxidant effects could be achieved using this sesquiterpene.

Structural and denaturation studies of two mutants of a cold adapted superoxide dismutase point to the importance of electrostatic interactions in protein stability.

PubMed

Merlino, Antonello; Russo Krauss, Irene; Castellano, Immacolata; Ruocco, Maria Rosaria; Capasso, Alessandra; De Vendittis, Emmanuele; Rossi, Bianca; Sica, Filomena

2014-03-01

A peculiar feature of the psychrophilic iron superoxide dismutase from Pseudoalteromonas haloplanktis (PhSOD) is the presence in its amino acid sequence of a reactive cysteine (Cys57). To define the role of this residue, a structural characterization of the effect of two PhSOD mutations, C57S and C57R, was performed. Thermal and denaturant-induced unfolding of wild type and mutant PhSOD followed by circular dichroism and fluorescence studies revealed that C→R substitution alters the thermal stability and the resistance against denaturants of the enzyme, whereas C57S only alters the stability of the protein against urea. The crystallographic data on the C57R mutation suggest an involvement of the Arg side chain in the formation of salt bridges on protein surface. These findings support the hypothesis that the thermal resistance of PhSOD relies on optimization of charge-charge interactions on its surface. Our study contributes to a deeper understanding of the denaturation mechanism of superoxide dismutases, suggesting the presence of a structural dimeric intermediate between the native state and the unfolded state. This hypothesis is supported by the crystalline and solution data on the reduced form of the enzyme. Copyright © 2014 Elsevier B.V. All rights reserved.

Superoxide Dismutase Mimics: Chemistry, Pharmacology, and Therapeutic Potential

PubMed Central

Rebouças, Júlio S.; Spasojević, Ivan

2010-01-01

Abstract Oxidative stress has become widely viewed as an underlying condition in a number of diseases, such as ischemia–reperfusion disorders, central nervous system disorders, cardiovascular conditions, cancer, and diabetes. Thus, natural and synthetic antioxidants have been actively sought. Superoxide dismutase is a first line of defense against oxidative stress under physiological and pathological conditions. Therefore, the development of therapeutics aimed at mimicking superoxide dismutase was a natural maneuver. Metalloporphyrins, as well as Mn cyclic polyamines, Mn salen derivatives and nitroxides were all originally developed as SOD mimics. The same thermodynamic and electrostatic properties that make them potent SOD mimics may allow them to reduce other reactive species such as peroxynitrite, peroxynitrite-derived CO3·−, peroxyl radical, and less efficiently H2O2. By doing so SOD mimics can decrease both primary and secondary oxidative events, the latter arising from the inhibition of cellular transcriptional activity. To better judge the therapeutic potential and the advantage of one over the other type of compound, comparative studies of different classes of drugs in the same cellular and/or animal models are needed. We here provide a comprehensive overview of the chemical properties and some in vivo effects observed with various classes of compounds with a special emphasis on porphyrin-based compounds. Antioxid. Redox Signal. 13, 877–918. PMID:20095865

Antioxidant effects of herbal therapies used by patients with inflammatory bowel disease: an in vitro study.

PubMed

Langmead, L; Dawson, C; Hawkins, C; Banna, N; Loo, S; Rampton, D S

2002-02-01

Herbal remedies used by patients for treatment of inflammatory bowel disease include slippery elm, fenugreek, devil's claw, Mexican yam, tormentil and wei tong ning, a traditional Chinese medicine. Reactive oxygen metabolites produced by inflamed colonic mucosa may be pathogenic. Aminosalicylates (5-ASA) are antioxidant and other such agents could be therapeutic. To assess the antioxidant effects of herbal remedies in cell-free oxidant-generating systems and inflamed human colorectal biopsies. Luminol-enhanced chemiluminescence in a xanthine/xanthine oxidase cell-free system was used to detect superoxide scavenging by herbs and 5-ASA, and fluorimetry to define peroxyl radical scavenging using a phycoerythrin degradation assay. Chemiluminescence was used to detect herbal effects on generation of oxygen radicals by mucosal biopsies from patients with active ulcerative colitis. Like 5-ASA, all herbs, except fenugreek, scavenged superoxide dose-dependently. All materials tested scavenged peroxyl dose-dependently. Oxygen radical release from biopsies was reduced after incubation in all herbs except Mexican yam, and by 5-ASA. All six herbal remedies have antioxidant effects. Fenugreek is not a superoxide scavenger, while Mexican yam did not inhibit radical generation by inflamed biopsies. Slippery elm, fenugreek, devil's claw, tormentil and wei tong ning merit formal evaluation as novel therapies in inflammatory bowel disease.

Use of Cu/Zn-superoxide dismutase tool for biomonitoring marine environment pollution in the Persian Gulf and the Gulf of Oman.

PubMed

Zeinali, Farrokhzad; Homaei, Ahmad; Kamrani, Ehsan; Patel, Seema

2018-04-30

Superoxide dismutase (SOD) is the pivotal antioxidant enzyme that defends organisms against the oxidative stresses of superoxide radicals. In this experimental study, purification of SOD from the leaves of Avicennia marina (grey mangrove or white mangrove) from the family Acanthaceae, located in Sirik mangrove forest on the shore of the Gulf of Oman was performed, for the intended characterization of SOD. The Sirik AmSOD (A. marina SOD) expressed optimum activity in the pH range of 6-9 with the maximum activity at pH 8. The optimal temperature for Sirik AmSOD activity was 70°C. Comparison of the pH and temperature optima in two regions (the Persian Gulf and the Gulf of Oman) showed significant differences with P<0.05. The SOD from the Persian Gulf was more resistant against the environmental stressors, because of the biochemical adaption to this environment, which is harsher. The evidence from these results suggests that AmSOD has different characteristics in each place, and mangroves undergo different adaptations and require different protections. The results of the enzymatic research can be useful for ecological management of organisms. Copyright © 2018 Elsevier Inc. All rights reserved.

Oxidative stress responses of Daphnia magna exposed to effluents spiked with emerging contaminants under ozonation and advanced oxidation processes.

PubMed

Oropesa, Ana Lourdes; Novais, Sara C; Lemos, Marco F L; Espejo, Azahara; Gravato, Carlos; Beltrán, Fernando

2017-01-01

Integration of conventional wastewater treatments with advanced oxidation processes (AOPs) has become of great interest to remove pharmaceuticals and their metabolites from wastewater. However, application of these technologies generates reactive oxygen species (ROS) that may reach superficial waters through effluents from sewage treatment plants. The main objective of the present study was to elucidate if ROS present in real effluents after biological and then chemical (single ozonation, solar photolytic ozonation, solar photocatalytic ozonation (TiO 2 , Fe 3 O 4 ) and solar photocatalytic oxidation (TiO 2 )) treatments induce oxidative stress in Daphnia magna. For this, the activity of two antioxidant enzymes (superoxide dismutase and catalase) and the level of lipid peroxidation were determined in Daphnia. The results of oxidative stress biomarkers studied suggest that D. magna is able to cope with the superoxide ion radical (O 2 · - ) present in the treated effluent due to single ozonation by mainly inducing the antioxidant activity superoxide dismutase, thus preventing lipid peroxidation. Lethal effects (measured in terms of immobility) were not observed in these organisms after exposure to any solution. Therefore, in order to probe the ecological efficiency of urban wastewater treatments, studies on lethal and sublethal effects in D. magna would be advisable.

Impact of the mitochondria-targeted antioxidant MitoQ on hypoxia-induced pulmonary hypertension.

PubMed

Pak, Oleg; Scheibe, Susan; Esfandiary, Azadeh; Gierhardt, Mareike; Sydykov, Akylbek; Logan, Angela; Fysikopoulos, Athanasios; Veit, Florian; Hecker, Matthias; Kroschel, Florian; Quanz, Karin; Erb, Alexandra; Schäfer, Katharina; Fassbinder, Mirja; Alebrahimdehkordi, Nasim; Ghofrani, Hossein A; Schermuly, Ralph T; Brandes, Ralf P; Seeger, Werner; Murphy, Michael P; Weissmann, Norbert; Sommer, Natascha

2018-02-01

Increased mitochondrial reactive oxygen species (ROS), particularly superoxide have been suggested to mediate hypoxic pulmonary vasoconstriction (HPV), chronic hypoxia-induced pulmonary hypertension (PH) and right ventricular (RV) remodelling.We determined ROS in acute, chronic hypoxia and investigated the effect of the mitochondria-targeted antioxidant MitoQ under these conditions.The effect of MitoQ or its inactive carrier substance, decyltriphenylphosphonium (TPP + ), on acute HPV (1% O 2 for 10 minutes) was investigated in isolated blood-free perfused mouse lungs. Mice exposed for 4 weeks to chronic hypoxia (10% O 2 ) or after banding of the main pulmonary artery (PAB) were treated with MitoQ or TPP + (50 mg/kg/day).Total cellular superoxide and mitochondrial ROS levels were increased in pulmonary artery smooth muscle cells (PASMC), but decreased in pulmonary fibroblasts in acute hypoxia. MitoQ significantly inhibited HPV and acute hypoxia-induced rise in superoxide concentration. ROS was decreased in PASMC, while it increased in the RV after chronic hypoxia. Correspondingly, MitoQ did not affect the development of chronic hypoxia-induced PH, but attenuated RV remodelling after chronic hypoxia as well as after PAB.Increased mitochondrial ROS of PASMC mediate acute HPV, but not chronic hypoxia-induced PH. MitoQ may be beneficial under conditions of exaggerated acute HPV. Copyright ©ERS 2018.

Sod1 Loss Induces Intrinsic Superoxide Accumulation Leading to p53-Mediated Growth Arrest and Apoptosis

PubMed Central

Watanabe, Kenji; Shibuya, Shuichi; Koyama, Hirofumi; Ozawa, Yusuke; Toda, Toshihiko; Yokote, Koutaro; Shimizu, Takahiko

2013-01-01

Oxidative damages induced by a redox imbalance cause age-related changes in cells and tissues. Superoxide dismutase (SOD) enzymes play a major role in the antioxidant system and they also catalyze superoxide radicals (O2•−). Since the loss of cytoplasmic SOD (SOD1) resulted in aging-like phenotypes in several types of mouse tissue, SOD1 is essential for the maintenance of tissue homeostasis. To clarify the cellular function of SOD1, we investigated the cellular phenotypes of Sod1-deficient fibroblasts. We demonstrated that Sod1 deficiency impaired proliferation and induced apoptosis associated with O2•− accumulation in the cytoplasm and mitochondria in fibroblasts. Sod1 loss also decreased the mitochondrial membrane potential and led to DNA damage-mediated p53 activation. Antioxidant treatments effectively improved the cellular phenotypes through suppression of both intracellular O2•− accumulation and p53 activation in Sod1-deficient fibroblasts. In vivo experiments revealed that transdermal treatment with a vitamin C derivative significantly reversed the skin thinning commonly associated with the upregulated p53 action in the skin. Our findings revealed that intrinsic O2•− accumulation promoted p53-mediated growth arrest and apoptosis as well as mitochondrial disfunction in the fibroblasts. PMID:23708100

Mitochondria-derived reactive oxygen species drive GANT61-induced mesothelioma cell apoptosis.

PubMed

Lim, Chuan Bian; Prêle, Cecilia M; Baltic, Svetlana; Arthur, Peter G; Creaney, Jenette; Watkins, D Neil; Thompson, Philip J; Mutsaers, Steven E

2015-01-30

Gli transcription factors of the Hedgehog (Hh) pathway have been reported to be drivers of malignant mesothelioma (MMe) cell survival. The Gli inhibitor GANT61 induces apoptosis in various cancer cell models, and has been associated directly with Gli inhibition. However various chemotherapeutics can induce cell death through generation of reactive oxygen species (ROS) but whether ROS mediates GANT61-induced apoptosis is unknown. In this study human MMe cells were treated with GANT61 and the mechanisms regulating cell death investigated. Exposure of MMe cells to GANT61 led to G1 phase arrest and apoptosis, which involved ROS but not its purported targets, GLI1 or GLI2. GANT61 triggered ROS generation and quenching of ROS protected MMe cells from GANT61-induced apoptosis. Furthermore, we demonstrated that mitochondria are important in mediating GANT61 effects: (1) ROS production and apoptosis were blocked by mitochondrial inhibitor rotenone; (2) GANT61 promoted superoxide formation in mitochondria; and (3) mitochondrial DNA-deficient LO68 cells failed to induce superoxide, and were more resistant to apoptosis induced by GANT61 than wild-type cells. Our data demonstrate for the first time that GANT61 induces apoptosis by promoting mitochondrial superoxide generation independent of Gli inhibition, and highlights the therapeutic potential of mitochondrial ROS-mediated anticancer drugs in MMe.

Characteristics of the Copper,Zinc Superoxide Dismutase of a Hadal Sea Cucumber (Paelopatides sp.) from the Mariana Trench.

PubMed

Li, Yanan; Kong, Xue; Chen, Jiawei; Liu, Helu; Zhang, Haibin

2018-05-18

Superoxide dismutases (SODs) are among the most important antioxidant enzymes and show great potential in preventing adverse effects during therapeutic trials. In the present study, cloning, expression, and characterization of a novel Cu,Zn superoxide dismutase (Ps-Cu,Zn-SOD) from a hadal sea cucumber ( Paelopatides sp.) were reported. Phylogenetic analysis showed that Ps-Cu,Zn-SOD belonged to a class of intracellular SOD. Its K m and V max were 0.0258 ± 0.0048 mM and 925.1816 ± 28.0430 units/mg, respectively. The low K m value of this enzyme represents a high substrate affinity and can adapt to the low metabolic rate of deep sea organisms. The enzyme functioned from 0 °C to 80 °C with an optimal temperature of 40 °C. Moreover, the enzyme activity was maintained up to 87.12% at 5 °C. The enzyme was active at pH 4 to 12 with an optimal pH of 8.5. Furthermore, Ps-Cu,Zn-SOD tolerated high concentration of urea and GuHCl, resisted hydrolysis by proteases, and maintained stability at high pressure. All these features demonstrated that the deep sea Ps-Cu,Zn-SOD is a potential candidate for application to the biopharmaceutical field.

Low-Dose Aronia melanocarpa Concentrate Attenuates Paraquat-Induced Neurotoxicity

PubMed Central

Case, A. J.; Agraz, D.; Ahmad, I. M.; Zimmerman, M. C.

2016-01-01

Herbicides containing paraquat may contribute to the pathogenesis of neurodegenerative disorders such as Parkinson's disease. Paraquat induces reactive oxygen species-mediated apoptosis in neurons, which is a primary mechanism behind its toxicity. We sought to test the effectiveness of a commercially available polyphenol-rich Aronia melanocarpa (aronia berry) concentrate in the amelioration of paraquat-induced neurotoxicity. Considering the abundance of antioxidants in aronia berries, we hypothesized that aronia berry concentrate attenuates the paraquat-induced increase in reactive oxygen species and protects against paraquat-mediated neuronal cell death. Using a neuronal cell culture model, we observed that low doses of aronia berry concentrate protected against paraquat-mediated neurotoxicity. Additionally, low doses of the concentrate attenuated the paraquat-induced increase in superoxide, hydrogen peroxide, and oxidized glutathione levels. Interestingly, high doses of aronia berry concentrate increased neuronal superoxide levels independent of paraquat, while at the same time decreasing hydrogen peroxide. Moreover, high-dose aronia berry concentrate potentiated paraquat-induced superoxide production and neuronal cell death. In summary, aronia berry concentrate at low doses restores the homeostatic redox environment of neurons treated with paraquat, while high doses exacerbate the imbalance leading to further cell death. Our findings support that moderate levels of aronia berry concentrate may prevent reactive oxygen species-mediated neurotoxicity. PMID:26770655

Low-Dose Aronia melanocarpa Concentrate Attenuates Paraquat-Induced Neurotoxicity.

PubMed

Case, A J; Agraz, D; Ahmad, I M; Zimmerman, M C

2016-01-01

Herbicides containing paraquat may contribute to the pathogenesis of neurodegenerative disorders such as Parkinson's disease. Paraquat induces reactive oxygen species-mediated apoptosis in neurons, which is a primary mechanism behind its toxicity. We sought to test the effectiveness of a commercially available polyphenol-rich Aronia melanocarpa (aronia berry) concentrate in the amelioration of paraquat-induced neurotoxicity. Considering the abundance of antioxidants in aronia berries, we hypothesized that aronia berry concentrate attenuates the paraquat-induced increase in reactive oxygen species and protects against paraquat-mediated neuronal cell death. Using a neuronal cell culture model, we observed that low doses of aronia berry concentrate protected against paraquat-mediated neurotoxicity. Additionally, low doses of the concentrate attenuated the paraquat-induced increase in superoxide, hydrogen peroxide, and oxidized glutathione levels. Interestingly, high doses of aronia berry concentrate increased neuronal superoxide levels independent of paraquat, while at the same time decreasing hydrogen peroxide. Moreover, high-dose aronia berry concentrate potentiated paraquat-induced superoxide production and neuronal cell death. In summary, aronia berry concentrate at low doses restores the homeostatic redox environment of neurons treated with paraquat, while high doses exacerbate the imbalance leading to further cell death. Our findings support that moderate levels of aronia berry concentrate may prevent reactive oxygen species-mediated neurotoxicity.

Cerebellar Expression of Copper Chaperone for Superoxide, Cytosolic Cu/Zn-Superoxide Dismutase, 4-Hydroxy-2-Nonenal, Acrolein and Heat Shock Protein 32 in Patients with Menkes Kinky Hair Disease: Immunohistochemical Study

PubMed Central

Yokoyama, Atsushi; Ohno, Kousaku; Hirano, Asao; Shintaku, Masayuki; Kato, Masako; Hayashi, Kazuhiko; Kato, Shinsuke

2014-01-01

Background To clarify the pathogenesis of cerebellar Purkinje cell death in patients with Menkes kinky hair disease (MD), a disorder of copper absorption, we investigated the morphological and functional abnormalities of residual Purkinje cells in MD patients and the mechanism of cell death. Methods Seven MD patients and 39 neurologically normal autopsy cases were studied. We performed histopathological and quantitative analyses of the Purkinje cells. In addition, we used immunohistochemistry to detect copper-dependent enzymes [cytosolic Cu/Zn-superoxide dismutase (SOD1) and copper chaperone for superoxide dismutase (CCS)], oxidative stress markers [4-hydroxy-2-nonenal (HNE) and acrolein] and heat shock protein 32 (hsp 32). Results The surviving MD Purkinje cells showed abnormal development, such as somatic sprouts and heterotopic location. Due to maldevelopment and degeneration, dendrites showed the cactus and weeping willow patterns. Axonal degeneration led to the formation of torpedoes. Quantitative analysis revealed loss of approximately 50% of the Purkinje cells in MD patients. Almost all of the normal Purkinje cells were positive for immunostaining by anti-CCS and anti-SOD1 antibodies, with staining of the cell bodies, dendrites and axons. Normal Purkinje cells were not stained by antibodies for HNE, acrolein or hsp 32. In MD patients, the majority of Purkinje cells were positive for CCS, but the positive rate for SOD1 was only about 23%. Approximately 56%, 42% and 40% of the Purkinje cells of MD patients were positive for HNE, acrolein and hsp 32, respectively. Conclusion In MD patients, about 50% of the Purkinje cells have been lost due to maldevelopment and degeneration. In the residual Purkinje cells, CCS expression seems to be nearly normal as a protective response to decreased SOD1 activity due to copper deficiency. Because oxidative stress is elevated secondary to decreased SOD1 activity, hsp 32 is induced as another protective mechanism. PMID:25067875

Cerebellar expression of copper chaperone for superoxide, cytosolic cu/zn-superoxide dismutase, 4-hydroxy-2-nonenal, acrolein and heat shock protein 32 in patients with menkes kinky hair disease: immunohistochemical study.

PubMed

Yokoyama, Atsushi; Ohno, Kousaku; Hirano, Asao; Shintaku, Masayuki; Kato, Masako; Hayashi, Kazuhiko; Kato, Shinsuke

2014-03-01

To clarify the pathogenesis of cerebellar Purkinje cell death in patients with Menkes kinky hair disease (MD), a disorder of copper absorption, we investigated the morphological and functional abnormalities of residual Purkinje cells in MD patients and the mechanism of cell death. Seven MD patients and 39 neurologically normal autopsy cases were studied. We performed histopathological and quantitative analyses of the Purkinje cells. In addition, we used immunohistochemistry to detect copper-dependent enzymes [cytosolic Cu/Zn-superoxide dismutase (SOD1) and copper chaperone for superoxide dismutase (CCS)], oxidative stress markers [4-hydroxy-2-nonenal (HNE) and acrolein] and heat shock protein 32 (hsp 32). The surviving MD Purkinje cells showed abnormal development, such as somatic sprouts and heterotopic location. Due to maldevelopment and degeneration, dendrites showed the cactus and weeping willow patterns. Axonal degeneration led to the formation of torpedoes. Quantitative analysis revealed loss of approximately 50% of the Purkinje cells in MD patients. Almost all of the normal Purkinje cells were positive for immunostaining by anti-CCS and anti-SOD1 antibodies, with staining of the cell bodies, dendrites and axons. Normal Purkinje cells were not stained by antibodies for HNE, acrolein or hsp 32. In MD patients, the majority of Purkinje cells were positive for CCS, but the positive rate for SOD1 was only about 23%. Approximately 56%, 42% and 40% of the Purkinje cells of MD patients were positive for HNE, acrolein and hsp 32, respectively. In MD patients, about 50% of the Purkinje cells have been lost due to maldevelopment and degeneration. In the residual Purkinje cells, CCS expression seems to be nearly normal as a protective response to decreased SOD1 activity due to copper deficiency. Because oxidative stress is elevated secondary to decreased SOD1 activity, hsp 32 is induced as another protective mechanism.

Escherichia coli avoids high dissolved oxygen stress by activation of SoxRS and manganese-superoxide dismutase.

PubMed

Baez, Antonino; Shiloach, Joseph

2013-03-12

High concentrations of reactive oxygen species (ROS) were reported to cause oxidative stress to E. coli cells associated with reduced or inhibited growth. The high ROS concentrations described in these reports were generated by exposing the bacteria to H2O2 and superoxide-generating chemicals which are non-physiological growth conditions. However, the effect of molecular oxygen on oxidative stress response has not been evaluated. Since the use of oxygen-enriched air is a common strategy to support high density growth of E. coli, it was important to investigate the effect of high dissolved oxygen concentrations on the physiology and growth of E. coli and the way it responds to oxidative stress. To determine the effect of elevated oxygen concentrations on the growth characteristics, specific gene expression and enzyme activity in E. coli, the parental and SOD-deficient strain were evaluated when the dissolved oxygen (dO2) level was increased from 30% to 300%. No significant differences in the growth parameters were observed in the parental strain except for a temporary decrease of the respiration and acetate accumulation profile. By performing transcriptional analysis, it was determined that the parental strain responded to the oxidative stress by activating the SoxRS regulon. However, following the dO2 switch, the SOD-deficient strain activated both the SoxRS and OxyR regulons but it was unable to resume its initial growth rate. The transcriptional analysis and enzyme activity results indicated that when E. coli is exposed to dO2 shift, the superoxide stress regulator SoxRS is activated and causes the stimulation of the superoxide dismutase system. This enables the E. coli to protect itself from the poisoning effects of oxygen. The OxyR protecting system was not activated, indicating that H2O2 did not increase to stressing levels.

A lithium–oxygen battery based on lithium superoxide

DOE PAGES

Lu, Jun; Jung Lee, Yun; Luo, Xiangyi; ...

2016-01-11

Batteries based on sodium superoxide and on potassium superoxide have recently been reported(1-3). But, there have been no reports of a battery based on lithium superoxide (LiO 2), despite much research(4-8) into the lithium-oxygen (Li-O 2) battery because of its potential high energy density. Several studies(9-16) of Li-O 2 batteries have found evidence of LiO 2 being formed as one component of the discharge product along with lithium peroxide (Li 2O 2). In addition, theoretical calculations have indicated that some forms of LiO 2 may have a long lifetime(17). Our studies also suggest that it might be possible to formmore » LiO 2 alone for use in a battery. However, solid LiO 2 has been difficult to synthesize in pure form(18) because it is thermodynamically unstable with respect to disproportionation, giving Li 2O 2 (refs 19, 20). We show that crystalline LiO 2 can be stabilized in a Li-O 2 battery by using a suitable graphene-based cathode. Various characterization techniques reveal no evidence for the presence of Li 2O 2. A novel templating growth mechanism involving the use of iridium nanoparticles on the cathode surface may be responsible for the growth of crystalline LiO 2. Our results demonstrate that the LiO 2 formed in the Li-O 2 battery is stable enough for the battery to be repeatedly charged and discharged with a very low charge potential (about 3.2 volts). We also anticipate that this discovery will lead to methods of synthesizing and stabilizing LiO 2, which could open the way to high-energy-density batteries based on LiO 2 as well as to other possible uses of this compound, such as oxygen storage.« less

Compartmentalized oxidative stress in dopaminergic cell death induced by pesticides and complex I inhibitors: Distinct roles of superoxide anion and superoxide dismutases

PubMed Central

Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Pickett, Chillian; Sumin, Li; Jones, Jocelyn; Chen, Han; Webb, Brian; Choi, Jae; Zhou, You; Zimmerman, Matthew C.; Franco, Rodrigo

2013-01-01

The loss of dopaminergic neurons induced by the parkinsonian toxins paraquat, rotenone and 1-methyl-4-phenylpyridinium (MPP+) is associated with oxidative stress. However, controversial reports exist regarding the source/compartmentalization of reactive oxygen species (ROS) generation and its exact role in cell death. We aimed to determine in detail the role of superoxide anion (O2•−), oxidative stress and their subcellular compartmentalization in dopaminergic cell death induced by parkinsonian toxins. Oxidative stress and ROS formation was determined in the cytosol, intermembrane (IMS) and mitochondrial matrix compartments, using dihydroethidine derivatives, the redox sensor roGFP, as well as electron paramagnetic resonance spectroscopy. Paraquat induced an increase in ROS and oxidative stress in both the cytosol and mitochondrial matrix prior to cell death. MPP+ and rotenone primarily induced an increase in ROS and oxidative stress in the mitochondrial matrix. No oxidative stress was detected at the level of the IMS. In contrast to previous studies, overexpression of manganese superoxide dismutase (MnSOD) or copper/zinc SOD (CuZnSOD) had no effect on ROS steady state levels, lipid peroxidation, loss of mitochondrial membrane potential (ΔΨm) and dopaminergic cell death induced by MPP+ or rotenone. In contrast, paraquat-induced oxidative stress and cell death were selectively reduced by MnSOD overexpression, but not by CuZnSOD or manganese-porphyrins. However, MnSOD also failed to prevent ΔΨm loss. Finally, paraquat, but not MPP+ or rotenone, induced the transcriptional activation the redox-sensitive antioxidant response elements (ARE) and nuclear factor kappa-B (NF-κB). These results demonstrate a selective role of mitochondrial O2•− in dopaminergic cell death induced by paraquat, and show that toxicity induced by the complex I inhibitors rotenone and MPP+ does not depend directly on mitochondrial O2•− formation. PMID:23602909

Antioxidant enzyme activity and malondialdehyde levels can be modulated by Piper betle, tocotrienol rich fraction and Chlorella vulgaris in aging C57BL/6 mice.

PubMed

Aliahmat, Nor Syahida; Noor, Mohd Razman Mohd; Yusof, Wan Junizam Wan; Makpol, Suzana; Ngah, Wan Zurinah Wan; Yusof, Yasmin Anum Mohd

2012-12-01

The aim of this study was to determine the erythrocyte antioxidant enzyme activity and the superoxide dismutase, catalase, glutathione peroxidase, and plasma malondialdehyde levels in aging mice and to evaluate how these measures are modulated by potential antioxidants, including the tocotrienol-rich fraction, Piper betle, and Chlorella vulgaris. One hundred and twenty male C57BL/6 inbred mice were divided into three age groups: young (6 months old), middle-aged (12 months old), and old (18 months old). Each age group consisted of two control groups (distilled water and olive oil) and three treatment groups: Piper betle (50 mg/kg body weight), tocotrienol-rich fraction (30 mg/kg), and Chlorella vulgaris (50 mg/kg). The duration of treatment for all three age groups was two months. Blood was withdrawn from the orbital sinus to determine the antioxidant enzyme activity and the malondialdehyde level. Piper betle increased the activities of catalase, glutathione peroxidase, and superoxide dismutase in the young, middle, and old age groups, respectively, when compared to control. The tocotrienol-rich fraction decreased the superoxide dismutase activity in the middle and the old age groups but had no effect on catalase or glutathione peroxidase activity for all age groups. Chlorella vulgaris had no effect on superoxide dismutase activity for all age groups but increased glutathione peroxidase and decreased catalase activity in the middle and the young age groups, respectively. Chlorella vulgaris reduced lipid peroxidation (malondialdehyde levels) in all age groups, but no significant changes were observed with the tocotrienol-rich fraction and the Piper betle treatments. We found equivocal age-related changes in erythrocyte antioxidant enzyme activity when mice were treated with Piper betle, the tocotrienol-rich fraction, and Chlorella vulgaris. However, Piper betle treatment showed increased antioxidant enzymes activity during aging.

Antioxidant enzyme activity and malondialdehyde levels can be modulated by Piper betle, tocotrienol rich fraction and Chlorella vulgaris in aging C57BL/6 mice

PubMed Central

Aliahmat, Nor Syahida; Noor, Mohd Razman Mohd; Yusof, Wan Junizam Wan; Makpol, Suzana; Ngah, Wan Zurinah Wan; Yusof, Yasmin Anum Mohd

2012-01-01

OBJECTIVE: The aim of this study was to determine the erythrocyte antioxidant enzyme activity and the superoxide dismutase, catalase, glutathione peroxidase, and plasma malondialdehyde levels in aging mice and to evaluate how these measures are modulated by potential antioxidants, including the tocotrienol-rich fraction, Piper betle, and Chlorella vulgaris. METHOD: One hundred and twenty male C57BL/6 inbred mice were divided into three age groups: young (6 months old), middle-aged (12 months old), and old (18 months old). Each age group consisted of two control groups (distilled water and olive oil) and three treatment groups: Piper betle (50 mg/kg body weight), tocotrienol-rich fraction (30 mg/kg), and Chlorella vulgaris (50 mg/kg). The duration of treatment for all three age groups was two months. Blood was withdrawn from the orbital sinus to determine the antioxidant enzyme activity and the malondialdehyde level. RESULTS: Piper betle increased the activities of catalase, glutathione peroxidase, and superoxide dismutase in the young, middle, and old age groups, respectively, when compared to control. The tocotrienol-rich fraction decreased the superoxide dismutase activity in the middle and the old age groups but had no effect on catalase or glutathione peroxidase activity for all age groups. Chlorella vulgaris had no effect on superoxide dismutase activity for all age groups but increased glutathione peroxidase and decreased catalase activity in the middle and the young age groups, respectively. Chlorella vulgaris reduced lipid peroxidation (malondialdehyde levels) in all age groups, but no significant changes were observed with the tocotrienol-rich fraction and the Piper betle treatments. CONCLUSION: We found equivocal age-related changes in erythrocyte antioxidant enzyme activity when mice were treated with Piper betle, the tocotrienol-rich fraction, and Chlorella vulgaris. However, Piper betle treatment showed increased antioxidant enzymes activity during aging. PMID:23295600

Direct Comparison of the Enzymatic Characteristics and Superoxide Production of the Four Aldehyde Oxidase Enzymes Present in Mouse.

PubMed

Kücükgöze, Gökhan; Terao, Mineko; Garattini, Enrico; Leimkühler, Silke

2017-08-01

Aldehyde oxidases (AOXs) are molybdoflavoenzymes with an important role in the metabolism and detoxification of heterocyclic compounds and aliphatic as well as aromatic aldehydes. The enzymes use oxygen as the terminal electron acceptor and produce reduced oxygen species during turnover. Four different enzymes, mAOX1, mAOX3, mAOX4, and mAOX2, which are the products of distinct genes, are present in the mouse. A direct and simultaneous comparison of the enzymatic properties and characteristics of the four enzymes has never been performed. In this report, the four catalytically active mAOX enzymes were purified after heterologous expression in Escherichia coli The kinetic parameters of the four mouse AOX enzymes were determined and compared with the use of six predicted substrates of physiologic and toxicological interest, i.e., retinaldehyde, N 1 -methylnicotinamide, pyridoxal, vanillin, 4-(dimethylamino)cinnamaldehyde ( p- DMAC), and salicylaldehyde. While retinaldehyde, vanillin, p- DMAC, and salycilaldehyde are efficient substrates for the four mouse AOX enzymes, N 1 -methylnicotinamide is not a substrate of mAOX1 or mAOX4, and pyridoxal is not metabolized by any of the purified enzymes. Overall, mAOX1, mAOX2, mAOX3, and mAOX4 are characterized by significantly different K M and k cat values for the active substrates. The four mouse AOXs are also characterized by quantitative differences in their ability to produce superoxide radicals. With respect to this last point, mAOX2 is the enzyme generating the largest rate of superoxide radicals of around 40% in relation to moles of substrate converted, and mAOX1, the homolog to the human enzyme, produces a rate of approximately 30% of superoxide radicals with the same substrate. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

Increased phospho-adducin immunoreactivity in a murine model of amyotrophic lateral sclerosis.

PubMed

Shan, X; Hu, J H; Cayabyab, F S; Krieger, C

2005-01-01

Adducins alpha, beta and gamma are proteins that link spectrin and actin in the regulation of cytoskeletal architecture and are substrates for protein kinase C and other signaling molecules. Previous studies have shown that expressions of phosphorylated adducin (phospho-adducin) and protein kinase C are increased in spinal cord tissue from patients who died with amyotrophic lateral sclerosis, a neurodegenerative disorder of motoneurons and other cells. However, the distribution of phospho-adducin immunoreactivity has not been described in the mammalian spinal cord. We have evaluated the distribution of immunoreactivity to serine/threonine-dependent phospho-adducin at a region corresponding to the myristoylated alanine-rich C kinase substrate-related domain of adducin in spinal cords of mice over-expressing mutant human superoxide dismutase, an animal model of amyotrophic lateral sclerosis, and in control littermates. We find phospho-adducin immunoreactivity in control spinal cord in ependymal cells surrounding the central canal, neurons and astrocytes. Phospho-adducin immunoreactivity is localized to the cell bodies, dendrites and axons of some motoneurons, as well as to astrocytes in the gray and white matter. Spinal cords of mutant human superoxide dismutase mice having motoneuron loss exhibit significantly increased phospho-adducin immunoreactivity in ventral and dorsal horn spinal cord regions, but not in ependyma surrounding the central canal, compared with control animals. Increased phospho-adducin immunoreactivity localizes predominantly to astrocytes and likely increases as a consequence of the astrogliosis that occurs in the mutant human superoxide dismutase mouse with disease progression. These findings demonstrate increased immunoreactivity against phosphorylated adducin at the myristoylated alanine-rich C kinase substrate domain in a murine model of amyotrophic lateral sclerosis. As adducin is a substrate for protein kinase C at the myristoylated alanine-rich C kinase substrate domain, the increased phospho-adducin immunoreactivity is likely a consequence of protein kinase C activation in neurons and astrocytes of the spinal cord and evidence for aberrant phosphorylation events in mutant human superoxide dismutase mice that may affect neuron survival.

Paroxysmal atrial fibrillation: dynamics of the main antioxidant enzymes--superoxide dismutase and catalase.

PubMed

Negreva, Mariya N; Penev, Atanas P; Georgiev, Svetoslav Zh; Aleksandrova, Albena A

2014-01-01

Researchers have a particularly strong interest in the mechanisms implicated in the clinical manifestation of atrial fibrillation. To examine dynamically the activity of the antioxidant enzymes, superoxide dismutase and catalase in patients with paroxysmal atrial fibrillation (duration < 48 hours). The studied parameters were examined in the erythrocytes of 51 patients (59.84 +/- 1.60, 26 men) immediately after their hospitalization, at 24 hours and 28 days after restoration of sinus rhythm. 52 controls (59.50 +/- 1.46, 26 men) were also included, none of which had a history of arrhythmia. Propafenone was used to manage the rhythm abnormality. The enzyme activity was determined by a spectrophotometric method. The average duration of atrial fibrillation episodes until the time of hospitalization was 8.14 hours (from 2 to 24 hours). During patient hospitalization the activity of superoxide dismutase and catalase was considerably higher compared to that of the controls (8.46 +/- 0.26 vs 5.81 +/- 0.14 U/mg Hb; 7.36 +/- 0.25 vs 4.76 +/- 0.12 E240/min/mg Hb; P < 0.001). This difference was maintained 24 hours after the rhythm regularization (7.19 +/- 0.25 vs 5.81 +/- 0.14 U/mg Hb, p < 0.001; 5.30 +/- 0.21 vs 4.76 +/- 0.12 E240/min/mg Hb, p < 0.05). Twenty-eight days after the restoration of sinus rhythm, the activity of catalase remained increased (5.11 +/- 0.08 vs 4.76 +/- 0.12 E240/min/mg Hb, p < 0.05). The paroxysmal atrial fibrillation in our study was characterized with significantly increased activity of superoxide dismutase and catalase even in the early hours of clinical manifestation of the disorder, which then slowly decreased with the restoration of sinus rhythm. Therefore, we can conclude that changes in oxidative status are closely related to the disease and are probably a part of the intimate mechanisms related to its initiation and clinical course.

Iron, copper, and manganese complexes with in vitro superoxide dismutase and/or catalase activities that keep Saccharomyces cerevisiae cells alive under severe oxidative stress.

PubMed

Ribeiro, Thales P; Fernandes, Christiane; Melo, Karen V; Ferreira, Sarah S; Lessa, Josane A; Franco, Roberto W A; Schenk, Gerhard; Pereira, Marcos D; Horn, Adolfo

2015-03-01

Due to their aerobic lifestyle, eukaryotic organisms have evolved different strategies to overcome oxidative stress. The recruitment of some specific metalloenzymes such as superoxide dismutases (SODs) and catalases (CATs) is of great importance for eliminating harmful reactive oxygen species (hydrogen peroxide and superoxide anion). Using the ligand HPClNOL {1-[bis(pyridin-2-ylmethyl)amino]-3-chloropropan-2-ol}, we have synthesized three coordination compounds containing iron(III), copper(II), and manganese(II) ions, which are also present in the active site of the above-noted metalloenzymes. These compounds were evaluated as SOD and CAT mimetics. The manganese and iron compounds showed both SOD and CAT activities, while copper showed only SOD activity. The copper and manganese in vitro SOD activities are very similar (IC50~0.4 μmol dm(-3)) and about 70-fold higher than those of iron. The manganese compound showed CAT activity higher than that of the iron species. Analyzing their capacity to protect Saccharomyces cerevisiae cells against oxidative stress (H2O2 and the O2(•-) radical), we observed that all compounds act as antioxidants, increasing the resistance of yeast cells mainly due to a reduction of lipid oxidation. Especially for the iron compound, the data indicate complete protection when wild-type cells were exposed to H2O2 or O2(•-) species. Interestingly, these compounds also compensate for both superoxide dismutase and catalase deficiencies; their antioxidant activity is metal ion dependent, in the order iron(III)>copper(II)>manganese(II). The protection mechanism employed by the complexes proved to be independent of the activation of transcription factors (such as Yap1, Hsf1, Msn2/Msn4) and protein synthesis. There is no direct relation between the in vitro and the in vivo antioxidant activities. Copyright © 2014 Elsevier Inc. All rights reserved.

Identification of two new polymorphisms in the manganese superoxide dismutase gene (Mn-SOD); Part of the etiology of Parkinson`s disease?

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eggers, B.; Kurth, J.H.; Kurth, M.C.

1994-09-01

Epidemiological studies suggest that several different environmental agents interact with a number of genetic elements to cause Parkinson`s disease (PD), a common neurodegenerative disease. Abnormalities of oxidative metabolism may be central to this process. Specifically, the production and degradation of dopamine may lead to toxic by-products and increased oxidative stress. Toxic by-products include hydrogen peroxide, superoxide, and hydroxyl radicals, all of which are implicated in the aging process of the central nervous system. Superoxide dismutase (SOD) catalyzes superoxide to hydrogen peroxide. Genetic predisposition to PD may be at least partially a result of certain SOD alleles. Using the cDNA sequencemore » of Mn-SOD gene, oligonucleotide primers were designed which span several presumptive splice junction sites. An approximatley 2.4kb PCR product was amplified from gDNA samples that span one or more intron near the 3{prime} end of the Mn-SOD cDNA sequence. The resultant product was screened with a panel of 4-cutters to identify fragments appropriate for SSCP analysis. Twenty-two gDNA samples were screened for SSCP and size differences of these PCR products. After digestion with AluI, two polymorphisms were observed. Two alleles with a size difference of 2-4 bp were observed by denaturing PAGE in one of the fragments. SSCP analysis revealed a polymorphism with 2 alleles in another fragment. Sequence analysis of these polymorphisms is in progress. DNA from several DEPH families was used to confirm Mendelian inheritance of these polymorphisms. Genomic DNA samples have been collected from 265 PD patients and 169 control individuals; allelic frequencies will be determined for these populations, compared by {chi}{sup 2} analysis, and relative risk calculated. These results may support a contribution of Mn-SOD in the genetic predisposition to PD.« less

Acute intermittent hypoxia induced phrenic long-term facilitation despite increased SOD1 expression in a rat model of ALS

PubMed Central

Nichols, Nicole L.; Satriotomo, Irawan; Harrigan, Daniel J.; Mitchell, Gordon S.

2015-01-01

Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease characterized by motor neuron death. Since most ALS patients succumb to ventilatory failure from loss of respiratory motor neurons, any effective ALS treatment must preserve and/or restore breathing capacity. In rats over-expressing mutated superoxide dismutase-1 (SOD1G93A), the capacity to increase phrenic motor output is decreased at disease end-stage, suggesting imminent ventilatory failure. Acute intermittent hypoxia (AIH) induces phrenic long-term facilitation (pLTF), a form of spinal respiratory motor plasticity with potential to restore phrenic motor output in clinical disorders that compromise breathing. Since pLTF requires NADPH oxidase activity and reactive oxygen species (ROS) formation, it is blocked by NADPH oxidase inhibition and SOD mimetics in normal rats. Thus, we hypothesized that SOD1G93A (mutant; MT) rats do not express AIH-induced pLTF due to over-expression of active mutant superoxide dismutase-1. AIH-induced pLTF and hypoglossal (XII) LTF were assessed in young, pre-symptomatic and end-stage anesthetized MT rats and age-matched wild-type littermates. Contrary to predictions, pLTF and XII LTF were observed in MT rats at all ages; at end-stage, pLTF was actually enhanced. SOD1 levels were elevated in young and pre-symptomatic MT rats, yet superoxide accumulation in putative phrenic motor neurons (assessed with dihydroethidium) was unchanged; however, superoxide accumulation significantly decreased at end-stage. Thus, compensatory mechanisms appear to maintain ROS homoeostasis until late in disease progression, preserving AIH-induced respiratory plasticity. Following intrathecal injections of an NADPH oxidase inhibitor (apocynin; 600µM; 12µL), pLTF was abolished in pre-symptomatic, but not end-stage MT rats, demonstrating that pLTF is NADPH oxidase dependent in pre-symptomatic, but NADPH oxidase independent in end-stage MT rats. Mechanisms preserving/enhancing the capacity for pLTF in MT rats are not known. PMID:26287750

Escherichia coli avoids high dissolved oxygen stress by activation of SoxRS and manganese-superoxide dismutase

PubMed Central

2013-01-01

Background High concentrations of reactive oxygen species (ROS) were reported to cause oxidative stress to E. coli cells associated with reduced or inhibited growth. The high ROS concentrations described in these reports were generated by exposing the bacteria to H2O2 and superoxide-generating chemicals which are non-physiological growth conditions. However, the effect of molecular oxygen on oxidative stress response has not been evaluated. Since the use of oxygen-enriched air is a common strategy to support high density growth of E. coli, it was important to investigate the effect of high dissolved oxygen concentrations on the physiology and growth of E. coli and the way it responds to oxidative stress. Results To determine the effect of elevated oxygen concentrations on the growth characteristics, specific gene expression and enzyme activity in E. coli, the parental and SOD-deficient strain were evaluated when the dissolved oxygen (dO2) level was increased from 30% to 300%. No significant differences in the growth parameters were observed in the parental strain except for a temporary decrease of the respiration and acetate accumulation profile. By performing transcriptional analysis, it was determined that the parental strain responded to the oxidative stress by activating the SoxRS regulon. However, following the dO2 switch, the SOD-deficient strain activated both the SoxRS and OxyR regulons but it was unable to resume its initial growth rate. Conclusion The transcriptional analysis and enzyme activity results indicated that when E. coli is exposed to dO2 shift, the superoxide stress regulator SoxRS is activated and causes the stimulation of the superoxide dismutase system. This enables the E. coli to protect itself from the poisoning effects of oxygen. The OxyR protecting system was not activated, indicating that H2O2 did not increase to stressing levels. PMID:23497217

Angiotensin II receptor one (AT1) mediates dextrose induced endoplasmic reticulum stress and superoxide production in human coronary artery endothelial cells.

PubMed

Haas, Michael J; Onstead-Haas, Luisa; Lee, Tracey; Torfah, Maisoon; Mooradian, Arshag D

2016-10-01

Renin-angiotensin-aldosterone system (RAAS) has been implicated in diabetes-related vascular complications partly through oxidative stress. To determine the role of angiotensin II receptor subtype one (AT1) in dextrose induced endoplasmic reticulum (ER) stress, another cellular stress implicated in vascular disease. Human coronary artery endothelial cells with or without AT1 receptor knock down were treated with 27.5mM dextrose for 24h in the presence of various pharmacologic blockers of RAAS and ER stress and superoxide (SO) production were measured. Transfection of cells with AT1 antisense RNA knocked down cellular AT1 by approximately 80%. The ER stress was measured using the placental alkaline phosphatase (ES-TRAP) assay and western blot analysis of glucose regulated protein 78 (GRP78), c-jun-N-terminal kinase 1 (JNK1), phospho-JNK1, eukaryotic translation initiation factor 2α (eIF2α) and phospho-eIF2α measurements. Superoxide (SO) generation was measured using the superoxide-reactive probe 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-A]pyrazin-3-one hydrochloride (MCLA) chemiluminescence. In cells with AT1 knock down, dextrose induced ER stress was significantly blunted and treatment with 27.5mM dextrose resulted in significantly smaller increase in SO production compared to 27.5mM dextrose treated and sham transfected cells. Dextrose induced ER stress was reduced with pharmacologic blockers of AT1 (losartan and candesartan) and mineralocorticoid receptor blocker (spironolactone) but not with angiotensin converting enzyme inhibitors (captopril and lisinopril). The dextrose induced SO generation was inhibited by all pharmacologic blockers of RAAS tested. The results indicate that dextrose induced ER stress and SO production in endothelial cells are mediated at least partly through AT1 receptor activation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

A lithium–oxygen battery based on lithium superoxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Jun; Jung Lee, Yun; Luo, Xiangyi

Batteries based on sodium superoxide and on potassium superoxide have recently been reported(1-3). But, there have been no reports of a battery based on lithium superoxide (LiO 2), despite much research(4-8) into the lithium-oxygen (Li-O 2) battery because of its potential high energy density. Several studies(9-16) of Li-O 2 batteries have found evidence of LiO 2 being formed as one component of the discharge product along with lithium peroxide (Li 2O 2). In addition, theoretical calculations have indicated that some forms of LiO 2 may have a long lifetime(17). Our studies also suggest that it might be possible to formmore » LiO 2 alone for use in a battery. However, solid LiO 2 has been difficult to synthesize in pure form(18) because it is thermodynamically unstable with respect to disproportionation, giving Li 2O 2 (refs 19, 20). We show that crystalline LiO 2 can be stabilized in a Li-O 2 battery by using a suitable graphene-based cathode. Various characterization techniques reveal no evidence for the presence of Li 2O 2. A novel templating growth mechanism involving the use of iridium nanoparticles on the cathode surface may be responsible for the growth of crystalline LiO 2. Our results demonstrate that the LiO 2 formed in the Li-O 2 battery is stable enough for the battery to be repeatedly charged and discharged with a very low charge potential (about 3.2 volts). We also anticipate that this discovery will lead to methods of synthesizing and stabilizing LiO 2, which could open the way to high-energy-density batteries based on LiO 2 as well as to other possible uses of this compound, such as oxygen storage.« less

Sevoflurane Inhalation Accelerates the Long-Term Memory Consolidation via Small GTPase Overexpression in the Hippocampus of Mice in Adolescence.

PubMed

Nakamura, Emi; Kinoshita, Hiroyuki; Feng, Guo-Gang; Hayashi, Hisaki; Satomoto, Maiko; Sato, Motohiko; Fujiwara, Yoshihiro

2016-01-01

Sevoflurane exposure impairs the long-term memory in neonates. Whether the exposure to animals in adolescence affects the memory, however, has been unclear. A small hydrolase enzyme of guanosine triphosphate (GTPase) rac1 plays a role in the F-actin dynamics related to the synaptic plasticity, as well as superoxide production via reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation. The current study was designed to examine whether sevoflurane exposure to mice in early adolescence modifies the long-term learning ability concomitantly with the changes in F-actin constitution as well as superoxide production in the hippocampus according to the levels of rac1 protein expression. Four-week-old mice were subjected to the evaluation of long-term learning ability for three days. On day one, each mouse was allowed to enter a dark chamber for five min to acclimatization. On day two, the procedure was repeated with the addition of an electric shock as soon as a mouse entered the dark chamber. All mice subsequently inhaled 2 L/min air with (Sevoflurane group) and without (Control group) 2.5% sevoflurane for three hours. On day three, each mouse was placed on the platform and retention time, which is the latency to enter the dark chamber, was examined. The brain removed after the behavior test, was used for analyses of immunofluorescence, Western immunoblotting and intracellular levels of superoxide. Sevoflurane exposure significantly prolonged retention time, indicating the enhanced long-term memory. Sevoflurane inhalation augmented F-actin constitution coexisting with the rac1 protein overexpression in the hippocampus whereas it did not alter the levels of superoxide. Sevoflurane exposure to 4-week-old mice accelerates the long-term memory concomitantly with the enhanced F-actin constitution coexisting with the small GTPase rac1 overexpression in the hippocampus. These results suggest that sevoflurane inhalation may amplify long-term memory consolidation via the increased cytoskeleton constitution in the hippocampus of animals in early adolescence.

Short-term regular aerobic exercise reduces oxidative stress produced by acute in the adipose microvasculature.

PubMed

Robinson, Austin T; Fancher, Ibra S; Sudhahar, Varadarajan; Bian, Jing Tan; Cook, Marc D; Mahmoud, Abeer M; Ali, Mohamed M; Ushio-Fukai, Masuko; Brown, Michael D; Fukai, Tohru; Phillips, Shane A

2017-05-01

High blood pressure has been shown to elicit impaired dilation in the vasculature. The purpose of this investigation was to elucidate the mechanisms through which high pressure may elicit vascular dysfunction and determine the mechanisms through which regular aerobic exercise protects arteries against high pressure. Male C57BL/6J mice were subjected to 2 wk of voluntary running (~6 km/day) for comparison with sedentary controls. Hindlimb adipose resistance arteries were dissected from mice for measurements of flow-induced dilation (FID; with or without high intraluminal pressure exposure) or protein expression of NADPH oxidase II (NOX II) and superoxide dismutase (SOD). Microvascular endothelial cells were subjected to high physiological laminar shear stress (20 dyn/cm 2 ) or static condition and treated with ANG II + pharmacological inhibitors. Cells were analyzed for the detection of ROS or collected for Western blot determination of NOX II and SOD. Resistance arteries from exercised mice demonstrated preserved FID after high pressure exposure, whereas FID was impaired in control mouse arteries. Inhibition of ANG II or NOX II restored impaired FID in control mouse arteries. High pressure increased superoxide levels in control mouse arteries but not in exercise mouse arteries, which exhibited greater ability to convert superoxide to H 2 O 2 Arteries from exercised mice exhibited less NOX II protein expression, more SOD isoform expression, and less sensitivity to ANG II. Endothelial cells subjected to laminar shear stress exhibited less NOX II subunit expression. In conclusion, aerobic exercise prevents high pressure-induced vascular dysfunction through an improved redox environment in the adipose microvasculature. NEW & NOTEWORTHY We describe potential mechanisms contributing to aerobic exercise-conferred protection against high intravascular pressure. Subcutaneous adipose microvessels from exercise mice express less NADPH oxidase (NOX) II and more superoxide dismutase (SOD) and demonstrate less sensitivity to ANG II. In microvascular endothelial cells, shear stress reduced NOX II but did not influence SOD expression.

Influence of different histidine sources and zinc supplementation of broiler diets on dipeptide content and antioxidant status of blood and meat.

PubMed

Kopeć, W; Jamroz, D; Wiliczkiewicz, A; Biazik, E; Pudlo, A; Hikawczuk, T; Skiba, T; Korzeniowska, M

2013-01-01

1. The objective of this study was to investigate how a diet containing spray-dried blood cells (SDBC) (4%) with or without zinc (Zn) would affect the concentration of two histidine heterodipeptides and the antioxidant status of broiler blood and breast muscles. 2. The study was carried out on 920 male Flex chickens randomly assigned to 4 dietary treatments: I - control, II - diet I with SDBC, III - diet I with SDBC and supplemented with Zn and IV - diet I supplemented with L-histidine. Birds were raised on floor littered with wood shavings, given free access to water and fed ad libitum. Performance indices were measured on d 1, 21 and 42. 3. The activity of antioxidant enzymes superoxide dismutase, catalase and glutathione peroxidase was analysed in plasma, erythrocytes and muscle tissue. The total antioxidant capacity of plasma and breast muscles was measured by 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, as well as by ferric reducing antioxidant power (FRAP). Carnosine/anserine content of meat and plasma were determined using HPLC. Diets and breast muscles were analysed for amino acid profile and selected microelement content. 4. Histidine supplementation of the diet increased glutathione peroxidase activity in plasma and superoxide dismutase activity in erythrocytes. Moreover, the addition of SDBC or pure histidine in the diet increased histidine dipeptide content and activated enzymatic and non-enzymatic antioxidant systems in chicken blood and muscles. However, it led to lower growth performance indices. 5. The enrichment of broiler diets with Zn increased the antioxidant potential and the activity of superoxide dismutase in plasma, which was independent of the histidine dipeptide concentration. Zn supplementation combined with SDBC in a broiler diet led to the increase of superoxide dismutase and glutathione peroxidase activity, but it did not affect the radical-scavenging or ferric iron reduction abilities of muscles.

Pro-oxidant mitochondrial matrix-targeted ubiquinone MitoQ10 acts as anti-oxidant at retarded electron transport or proton pumping within Complex I.

PubMed

Plecitá-Hlavatá, Lydie; Jezek, Jan; Jezek, Petr

2009-01-01

Oxidative stress of mitochondrial origin, i.e. elevated mitochondrial superoxide production, belongs to major factors determining aging and oxidative-stress-related diseases. Antioxidants, such as the mitochondria-targeted coenzyme Q, MitoQ(10), may prevent or cure these pathological conditions. To elucidate pro- and anti-oxidant action of MitoQ(10), we studied its effects on HepG2 cell respiration, mitochondrial network morphology, and rates of superoxide release (above that neutralized by superoxide dismutase) to the mitochondrial matrix (J(m)). MitoSOX Red fluorescence confocal microscopy monitoring of J(m) rates showed pro-oxidant effects of 3.5-fold increased J(m) with MitoQ(10). MitoQ(10) induced fission of the mitochondrial network which was recovered after 24h. In rotenone-inhibited HepG2 cells (i.e., already under oxidative stress) MitoQ(10) sharply decreased rotenone-induced J(m), but not together with the Complex II inhibitor thenoyltrifluoroacetone. Respiration of HepG2 cells and isolated rat liver mitochondria with MitoQ(10) increased independently of rotenone. The increase was prevented by thenoyltrifluoroacetone. These results suggest that MitoQ(10) accepts electrons prior to the rotenone-bound Q-site, and the Complex II reverse mode oxidizes MitoQ(10)H(2) to regenerate MitoQ(10). Consequently, MitoQ(10) has a pro-oxidant role in intact cells, whereas it serves as an antioxidant when Complex I-derived superoxide generation is already elevated due to electron flow retardation. Moreover, unlike mitochondrial uncoupling, MitoQ(10) exerted its antioxidant role when Complex I proton pumping was retarded by a hydrophobic amiloride, 5-(N-ethyl-N-isopropyl) amiloride. Consequently, MitoQ(10) may be useful in the treatment of diseases originating from impairment of respiratory chain Complex I due to oxidatively damaged mitochondrial DNA, when its targeted delivery to pathogenic tissues is ensured.

Laboratory Measurements of Oxygen Gas Release from Basaltic Minerals Exposed to UV- Radiation: Implications for the Viking Gas Exchange Experiments

NASA Astrophysics Data System (ADS)

Hurowitz, J. A.; Yen, A. S.

2007-12-01

The biology experiments onboard the Viking Landers determined that the Martian soils at Chryse and Utopia Planitia contain an unknown chemical compound of a highly oxidizing nature. The Gas Exchange Experiments (GEx) demonstrated that the humidification of a 1-cc Martian soil sample resulted in the production of as much as 790 nanomoles of oxygen gas. Yen et al. (2000) have provided experimental evidence that superoxide radicals can be generated on plagioclase feldspar (labradorite) grain surfaces by exposure to ultraviolet (UV) light in the presence of oxygen gas. Adsorbed superoxide radicals are thought to react readily with water vapor, and produce oxygen gas in quantities sufficient to explain the Viking GEx results. Direct evidence for the formation of oxygen gas, however, was not provided in the experiments of Yen et al (2000). Accordingly, the motivation of this study is to determine whether superoxide radicals adsorbed on labradorite surfaces are capable of producing oxygen gas upon exposure to water vapor. We have constructed an experimental apparatus that is capable of monitoring oxygen gas release from basaltic mineral powders that have been exposed to UV-radiation under Martian atmospheric pressure conditions. The apparatus consists of a stainless-steel vacuum chamber with a UV- transparent window where sample radiation exposures are performed. The vacuum chamber has multiple valved ports for injection of gases and water vapor. The vacuum chamber is connected via a precision leak valve to a quadrupole mass spectrometer, which measures changes in the composition of the headspace gases over our mineral samples. We will report on the results of our experiments, which are aimed at detecting and quantifying oxygen gas release from UV-exposed basaltic mineral samples using this new experimental facility. These results will further constrain whether superoxide ions adsorbed on mineral surfaces provide a viable explanation for the Viking GEx results, which have been of considerable controversy in the roughly three decades since the measurements were first made.

Influence of vitamin C and vitamin E on redox signaling: Implications for exercise adaptations.

PubMed

Cobley, James N; McHardy, Helen; Morton, James P; Nikolaidis, Michalis G; Close, Graeme L

2015-07-01

The exogenous antioxidants vitamin C (ascorbate) and vitamin E (α-tocopherol) often blunt favorable cell signaling responses to exercise, suggesting that redox signaling contributes to exercise adaptations. Current theories posit that this antioxidant paradigm interferes with redox signaling by attenuating exercise-induced reactive oxygen species (ROS) and reactive nitrogen species (RNS) generation. The well-documented in vitro antioxidant actions of ascorbate and α-tocopherol and characterization of the type and source of the ROS/RNS produced during exercise theoretically enable identification of redox-dependent mechanisms responsible for the blunting of favorable cell signaling responses to exercise. This review aimed to apply this reasoning to determine how the aforementioned antioxidants might attenuate exercise-induced ROS/RNS production. The principal outcomes of this analysis are (1) neither antioxidant is likely to attenuate nitric oxide signaling either directly (reaction with nitric oxide) or indirectly (reaction with derivatives, e.g., peroxynitrite); (2) neither antioxidant reacts appreciably with hydrogen peroxide, a key effector of redox signaling; (3) ascorbate but not α-tocopherol has the capacity to attenuate exercise-induced superoxide generation; and (4) alternate mechanisms, namely pro-oxidant side reactions and/or reduction of bioactive oxidized macromolecule adducts, are unlikely to interfere with exercise-induced redox signaling. Out of all the possibilities considered, ascorbate-mediated suppression of superoxide generation with attendant implications for hydrogen peroxide signaling is arguably the most cogent explanation for blunting of favorable cell signaling responses to exercise. However, this mechanism is dependent on ascorbate accumulating at sites rich in NADPH oxidases, principal contributors to contraction-mediated superoxide generation, and outcompeting nitric oxide and superoxide dismutase isoforms. The major conclusions of this review are: (1) direct evidence for interference of ascorbate and α-tocopherol with exercise-induced ROS/RNS production is lacking; (2) theoretical analysis reveals that both antioxidants are unlikely to have a major impact on exercise-induced redox signaling; and (3) it is worth considering alternate redox-independent mechanisms. Copyright © 2015 Elsevier Inc. All rights reserved.

The phagocyte respiratory burst: Historical perspectives and recent advances.

PubMed

Thomas, David C

2017-12-01

When exposed to certain stimuli, phagocytes (including neutrophils, macrophages and eosinophils) undergo marked changes in the way they handle oxygen. Firstly, their rate of oxygen uptake increases greatly. This is accompanied by (i) the production of large amounts of superoxide and hydrogen peroxide and (ii) the metabolism of large quantities of glucose through the hexose monophosphate shunt. We now know that the oxygen used is not for respiration but for the production of powerful microbiocidal agents downstream of the initial production of superoxide. Concomitantly, glucose is oxidised through the hexose monophosphate shunt to re-generate the NADPH that has been consumed through the reduction of molecular oxygen to generate superoxide. This phagocyte respiratory burst is generated by an NADPH oxidase multi-protein complex that has a catalytic core consisting of membrane-bound gp91phox (CYBB) and p22phox (CYBA) sub-units and cytosolic components p47phox (NCF1), p67phox (NCF2) and p40phox (NCF4). Finally, another cytosolic component, the small G-protein Rac (Rac2 in neutrophils and Rac1 in macrophages) is also required for full activation. The importance of the complex in host defence is underlined by chronic granulomatous disease, a severe life-limiting immunodeficiency caused by mutations in the genes encoding the individual subunits. In this review, I will discuss the experimental evidence that underlies our knowledge of the respiratory burst, outlining how elegant biochemical analysis, coupled with study of patients deficient in the various subunits has helped elucidate the function of this essential part of innate immunity. I will also discuss some exciting recent studies that shed new light on how the abundance of the various components is controlled. Finally, I will explore the emerging role of reactive oxygen species such as superoxide and hydrogen peroxide in the pathogenesis of major human diseases including auto-inflammatory diseases. Copyright © 2017. Published by Elsevier B.V.

Structural, functional and immunogenic insights on Cu,Zn superoxide dismutase pathogenic virulence factors from Neisseria meningitidis and Brucella abortus

DOE PAGES

Pratt, Ashley J.; DiDonato, Michael; Shin, David S.; ...

2015-10-12

Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and health consequences. Superoxide dismutases are master regulators of reactive oxygen, general pathogenicity factors and therefore therapeutic targets. Cu,Zn superoxide dismutases (SODs) localized to the periplasm promote survival by detoxifying superoxide radicals generated by major host antimicrobial immune responses. We discovered that passive immunization with an antibody directed at N. meningitidis SOD (NmSOD) was protective in a mouse infection model. To define the relevant atomicmore » details and solution assembly states of this important virulence factor, we report high-resolution and X-ray scattering analyses of NmSOD and SOD from B. abortus (BaSOD). The NmSOD structures revealed an auxiliary tetrahedral Cu-binding site bridging the dimer interface; mutational analyses suggested that this metal site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses informed us about electrostatic substrate guidance, dimer assembly and an exposed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure provided insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes and suggest general targets for anti-bacterial immune responses. The identified functional contributions, motifs, and targets distinguishing bacterial and eukaryotic SOD assemblies presented here provide a foundation for efforts to develop SOD-specific inhibitors or vaccines against these harmful pathogens. IMPORTANCE By protecting microbes against reactive oxygen insults, Cu,Zn superoxide dismutases (SODs) aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific differences relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of Neisseria meningitidis and Brucella abortus SODs, we used X-ray structures, enzymology, modeling and murine infection experiments. We identified virulence determinants common to both homologs, assembly differences and a unique metal reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and basis for SOD-specific drugs and extension of immunogen design to target two important pathogens that continue to pose global health threats.« less

Antioxidative effects of a processed grain food.

PubMed

Minamiyama, Y; Yoshikawa, T; Tanigawa, T; Takahashi, S; Naito, Y; Ichikawa, H; Kondo, M

1994-10-01

Antioxidant biofactor: AOB is a unique processed grain food. It is a yellow-green powder. It contains the following extracts: germ extracts, soybean, rice bran, tear grass, sesame, wheat, citron, green tea, green leaf extract, and malted rice. These materials were slowly roasted under a powdered oure at less than 60 degrees C and fermented with Aspergillus oryzae over 3 days to transform each ingredient into low molecular weight substances. These conditions were different by each material, environmental humidity and temperature. It probably contains a variety of substances having antioxidant activity including flavonoids, alpha-tocopherol, vitamin C, and tannins. We investigated its antioxidative properties using electron spin resonance (ESR) and autoxidation of rat brain homogenates. The superoxide, hydroxyl radical, and the stable free radical, diphenyl-p-picrylhydrazyl (DPPH) radical scavenging activity of AOB was investigated using ESR spectrometry. In an in vitro study, a suspension of AOB was added directly to a superoxide generating system (hypoxanthine-xanthine oxidase; HX/XO) and investigated using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trapping agent. At final concentrations of 0.01, 0.05, and 0.1 mg/ml, AOB dose-dependent scavenging activity was observed as 0.103, 0.619, and 1.369 U/ml, respectively. A concentration of 1.0 mg/ml completely scavenged DMPO-OOH signals; 1.0 mg/ml of AOB inhibited the DMPO-OH signal generated by Fenton's reaction, but its inhibitory effect was not competitive, and was inhibition of the Fenton's reaction. 1.0, 3.0, and 5.0 mg/ml of AOB were significantly inhibited the DPPH radical. In an in vivo study, rats were fed AOB orally at doses of 1 or 5 g/day for 24 h or for 3 days and the superoxide scavenging activity was measured in plasma. With the administration of 1 g/day for 3 days, the superoxide scavenging activity was about 1.8 times that of the control group fed a basal diet; 1.5 times the control with 5 g/day for 1 day, and 2.6 times the control with 5 g/day for 3 days, all of which represented significant increases in superoxide scavenging activity. AOB strongly inhibited the autoxidation of rat brain homogenates in vitro in a dose-dependent manner. However, each ingredient before roast and fermentation little inhibited lipid peroxidation. Roasting and fermentation with A. oryzae way be important to transform each ingredient into low molecular weight substances. Therefore, it was suggested that AOB possesses strong antioxidant and free radical scavenging activities.

Structural, functional and immunogenic insights on Cu,Zn superoxide dismutase pathogenic virulence factors from Neisseria meningitidis and Brucella abortus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pratt, Ashley J.; DiDonato, Michael; Shin, David S.

Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and health consequences. Superoxide dismutases are master regulators of reactive oxygen, general pathogenicity factors and therefore therapeutic targets. Cu,Zn superoxide dismutases (SODs) localized to the periplasm promote survival by detoxifying superoxide radicals generated by major host antimicrobial immune responses. We discovered that passive immunization with an antibody directed at N. meningitidis SOD (NmSOD) was protective in a mouse infection model. To define the relevant atomicmore » details and solution assembly states of this important virulence factor, we report high-resolution and X-ray scattering analyses of NmSOD and SOD from B. abortus (BaSOD). The NmSOD structures revealed an auxiliary tetrahedral Cu-binding site bridging the dimer interface; mutational analyses suggested that this metal site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses informed us about electrostatic substrate guidance, dimer assembly and an exposed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure provided insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes and suggest general targets for anti-bacterial immune responses. The identified functional contributions, motifs, and targets distinguishing bacterial and eukaryotic SOD assemblies presented here provide a foundation for efforts to develop SOD-specific inhibitors or vaccines against these harmful pathogens. IMPORTANCE By protecting microbes against reactive oxygen insults, Cu,Zn superoxide dismutases (SODs) aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific differences relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of Neisseria meningitidis and Brucella abortus SODs, we used X-ray structures, enzymology, modeling and murine infection experiments. We identified virulence determinants common to both homologs, assembly differences and a unique metal reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and basis for SOD-specific drugs and extension of immunogen design to target two important pathogens that continue to pose global health threats.« less

New Insights into the Instability of Discharge Products in Na-O2 Batteries.

PubMed

Landa-Medrano, Imanol; Pinedo, Ricardo; Bi, Xuanxuan; Ruiz de Larramendi, Idoia; Lezama, Luis; Janek, Jürgen; Amine, Khalil; Lu, Jun; Rojo, Teófilo

2016-08-10

Sodium-oxygen batteries currently stimulate extensive research due to their high theoretical energy density and improved operational stability when compared to lithium-oxygen batteries. Cell stability, however, needs to be demonstrated also under resting conditions before future implementation of these batteries. In this work we analyze the effect of resting periods on the stability of the sodium superoxide (NaO2) discharge product. The instability of NaO2 in the cell environment is demonstrated leading to the evolution of oxygen during the resting period and the decrease of the cell efficiency. In addition, migration of the superoxide anion (O2(-)) in the electrolyte is observed and demonstrated to be an important factor affecting Coulombic efficiency.

New Insights into the Instability of Discharge Products in Na–O 2 Batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Landa-Medrano, Imanol; Pinedo, Ricardo; Bi, Xuanxuan

2016-08-10

Sodium–oxygen batteries currently stimulate extensive research due to their high theoretical energy density and improved operational stability when compared to lithium–oxygen batteries. Cell stability, however, needs to be demonstrated also under resting conditions before future implementation of these batteries. In this work we analyze the effect of resting periods on the stability of the sodium superoxide (NaO 2) discharge product. The instability of NaO 2 in the cell environment is demonstrated leading to the evolution of oxygen during the resting period and the decrease of the cell efficiency. In addition, migration of the superoxide anion (O2–) in the electrolyte ismore » observed and demonstrated to be an important factor affecting Coulombic efficiency.« less

Activity of components of the antioxidant system in the roots of potato plants at short-term temperature drop and invasion with parasitic nematodes.

PubMed

Lavrova, V V; Matveeva, E M; Zinovieva, S V

2017-09-01

The activity of catalase and superoxide dismutase in the roots of susceptible plants and plants exposed to alternating temperatures, which were infected with the phytoparasitic nematode G. rostochiensis, was studied. It was found that, throughout the invasion period, the plants susceptible to invasion exhibited a high activity of these enzymes, which allowed them to maintain an active defense against the oxidative stress caused by the invasion and subsequent life activity of larvae. For the plants exposed to alternating temperatures, a decrease in the activity of catalase and superoxide dismutase at the early stages of invasion and an increase in the activity of these enzymes at the later stages was detected.