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Sample records for high-isoelectric-point superoxide dismutase1cw

  1. Air Revitalization Using Superoxides

    NASA Technical Reports Server (NTRS)

    Wydeven, Theodore; Wood, Peter C.; Spitze, L. A.

    1988-01-01

    Pellets made from powder mixtures of potassium superoxide, KO2, and calcium superoxide, Ca(O2)2, proven markedly superior to pellets of pure KO2 for adding O2 to and removing CO2 from atmospheric-pressure flow of humidified CO2 in He. Superoxides used extensively to supply O2 and scrub CO2 in variety of ambient-pressure life-support applications, including portable self-contained breathing apparatuses, spacecraft, and undersea submersible craft.

  2. 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.

  3. Models of Superoxide Dismutases

    SciTech Connect

    Cabelli, Diane E.; Riley, Dennis; Rodriguez, Jorge A.; Valentine, Joan Selverstone; Zhu, Haining

    1998-05-20

    In this review we have focused much of our discussion on the mechanistic details of how the native enzymes function and how mechanistic developments/insights with synthetic small molecule complexes possessing SOD activity have influenced our understanding of the electron transfer processes involved with the natural enzymes. A few overriding themes have emerged. Clearly, the SOD enzymes operate at near diffusion controlled rates and to achieve such catalytic turnover activity, several important physical principles must be operative. Such fast electron transfer processes requires a role for protons; i.e., proton-coupled electron transfer (''H-atom transfer'') solves the dilemma of charge separation developing in the transition state for the electron transfer step. Additionally, outer-sphere electron transfer is likely a most important pathway for manganese and iron dismutases. This situation arises because the ligand exchange rates on these two ions in water never exceed {approx}10{sup +7} s{sup -1}; consequently, 10{sup +9} catalytic rates require more subtle mechanistic insights. In contrast, copper complexes can achieve diffusion controlled (>10{sup +9}) exchange rates in water; thus inner-sphere electron transfer processes are more likely to be operative in the Cu/Zn enzymes. Recent studies have continued to expand our understanding of the mechanism of action of this most important class of redox active enzymes, the superoxide dismutases, which have been critical in the successful adaptation of life on this planet to an oxygen-based metabolism. The design of SOD mimic drugs, synthetic models compounds that incorporate this superoxide dismutase catalytic activity and are capable of functioning in vivo, offers clear potential benefits in the control of diseases, ranging from the control of neurodegenerative conditions, such as Parkinson's or Alzheimer's disease, to cancer.

  4. 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.

  5. Superoxide dismutases in chronic gastritis.

    PubMed

    Švagelj, Dražen; Terzić, Velimir; Dovhanj, Jasna; Švagelj, Marija; Cvrković, Mirta; Švagelj, Ivan

    2016-04-01

    Human gastric diseases have shown significant changes in the activity and expression of superoxide dismutase (SOD) isoforms. The aim of this study was to detect Mn-SOD activity and expression in the tissue of gastric mucosa, primarily in chronic gastritis (immunohistochemical Helicobacter pylori-negative gastritis, without other pathohistological changes) and to evaluate their possible connection with pathohistological diagnosis. We examined 51 consecutive outpatients undergoing endoscopy for upper gastrointestinal symptoms. Patients were classified based on their histopathological examinations and divided into three groups: 51 patients (archive samples between 2004-2009) with chronic immunohistochemical Helicobacter pylori-negative gastritis (mononuclear cells infiltration were graded as absent, moderate, severe) divided into three groups. Severity of gastritis was graded according to the updated Sydney system. Gastric tissue samples were used to determine the expression of Mn-SOD with anti-Mn-SOD Ab immunohistochemically. The Mn-SOD expression was more frequently present in specimens with severe and moderate inflammation of gastric mucosa than in those with normal mucosa. In patients with normal histological finding, positive immunoreactivity of Mn-SOD was not found. Our results determine the changes in Mn-SOD expression occurring in the normal gastric mucosa that had undergone changes in the intensity of chronic inflammatory infiltrates in the lamina propria. PMID:26765960

  6. Superoxide targets calcineurin signaling in vascular endothelium

    SciTech Connect

    Namgaladze, Dmitry . E-mail: dmitry@zbc.kgu.de; Shcherbyna, Ivanna; Kienhoefer, Joachim; Hofer, H. Werner; Ullrich, Volker

    2005-09-09

    Superoxide emerges as key regulatory molecule in many aspects of vascular physiology and disease, but identification of superoxide targets in the vasculature remains elusive. In this work, we investigated the possibility of inhibition of protein phosphatase calcineurin by superoxide in endothelial cells. We employed a redox cycler 2,3-dimethoxy-1,4-naphthoquinone (DMNQ) to generate superoxide inside the cells. DMNQ caused inhibition of cellular calcineurin phosphatase activity, which was reversible upon DMNQ removal. Inhibition was suppressed by pre-incubating the cells with copper/zinc superoxide dismutase (Cu,ZnSOD). In addition, reducing cellular Cu,ZnSOD activity by diethylthiocarbamic acid treatment resulted in calcineurin inhibition and enhanced sensitivity to DMNQ. Further, we could show that DMNQ inhibits calcineurin-dependent nuclear translocation and transcriptional activation of NFAT transcription factor, and Cu,ZnSOD or superoxide scavenger Tiron reduced the inhibition. Thus, superoxide generation in endothelial cells results in inhibition of calcineurin signaling, which could have important pathophysiological implications in the vasculature.

  7. Metal Uptake by Manganese Superoxide Dismutase

    PubMed Central

    Whittaker, James W.

    2009-01-01

    Manganese superoxide dismutase is an important antioxidant defense metalloenzyme that protects cells from damage by the toxic oxygen metabolite, superoxide free radical, formed as an unavoidable by-product of aerobic metabolism. Many years of research have gone into understanding how the metal cofactor interacts with small molecules in its catalytic role. In contrast, very little is presently known about how the protein acquires its metal cofactor, an important step in the maturation of the protein and one that is absolutely required for its biological function. Recent work is beginning to provide insight into the mechanisms of metal delivery to manganese superoxide dismutase in vivo and in vitro. PMID:19699328

  8. 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.

  9. 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.

  10. Superoxide radical induces sclerotial differentiation in filamentous phytopathogenic fungi: a superoxide dismutase mimetics study.

    PubMed

    Papapostolou, Ioannis; Georgiou, Christos D

    2010-03-01

    This study shows that the superoxide radical (O(2) *( -)), a direct indicator of oxidative stress, is involved in the differentiation of the phytopathogenic filamentous fungi Rhizoctonia solani, Sclerotinia sclerotiorum, Sclerotium rolfsii and Sclerotinia minor, shown by using superoxide dismutase (SOD) mimetics to decrease their sclerotial differentiation. The production rate of O(2) *(-) and SOD levels in these fungi, as expected, were significantly lowered by the SOD mimetics, with concomitant decrease of the indirect indicator of oxidative stress, lipid peroxidation. PMID:20007647

  11. Superoxide Dismutases and Reactive Oxygen Species

    SciTech Connect

    Cabelli, D.E.

    2011-01-01

    The 'free radical theory' of aging was introduced over a half-century ago. In this theory, much of the deleterious effects of aging were attributed to the cumulative buildup of damage from reactive oxygen species. When discussing reactive oxygen species (ROS) in aerobic systems, both superoxide radicals (O{sub 2}{sup -}) and superoxide dismutases (SODs) are considered to play prominent roles. O{sub 2}{sup -} is formed by attachment of the electron to oxygen (O{sub 2}) that is present in tens to hundreds of micromolar concentration in vivo. SODs are enzymes that serve to eliminate O{sub 2}{sup -} by rapidly converting it to O{sub 2} and hydrogen peroxide (H{sub 2}O{sub 2}). Both the radical and the enzyme will be discussed with the focus on the systems that are present in humans.

  12. Superoxide reactivates nitric oxide-inhibited catalase.

    PubMed

    Kim, Y S; Han, S

    2000-12-01

    Catalase binds nitric oxide (NO) to generate ferricatalase-NO, an inhibited form of the enzyme. Superoxide (O2-) is also an inactivator of the enzyme. We found, however, that O2- efficiently converted the inhibited ferricatalase-NO to the active ferricatalase without producing detectable intermediates. The reaction slowed down when O2- was disproportionated to H2O2 and O2 by superoxide dismutase, but H2O2 could displace the heme-bound NO slowly to regenerate ferricatalase. Reactivation was observed even under simultaneous generation of NO and O2-, suggesting that ferricatalase-NO reacts with O2- fast enough to compete with the rapid reaction of O2- and NO. Formation of peroxynitrite by the simultaneous generation of NO and O2- was only partially inhibited by ferricatalase, presumably due to slow binding of NO to catalase in comparison with the reaction of NO and O2-. PMID:11209763

  13. The structural biochemistry of the superoxide dismutases

    PubMed Central

    Perry, J.J.P.; Shin, D.S.; Getzoff, E.D.; Tainer, J.A.

    2011-01-01

    The discovery of superoxide dismutases (SODs), which convert superoxide radicals to molecular oxygen and hydrogen peroxide, has been termed the most important discovery of modern biology never to win a Nobel Prize. Here, we review the reasons this discovery has been underappreciated, as well as discuss the robust results supporting its premier biological importance and utility for current research. We highlight our understanding of SOD function gained through structural biology analyses, which reveal important hydrogen-bonding schemes and metal-binding motifs. These structural features create remarkable enzymes that promote catalysis at faster than diffusion-limited rates by using electrostatic guidance. These architectures additionally alter the redox potential of the active site metal center to a range suitable for the superoxide disproportionation reaction and protect against inhibition of catalysis by molecules such as phosphate. SOD structures may also control their enzymatic activity through product inhibition; manipulation of these product inhibition levels has the potential to generate therapeutic forms of SOD. Markedly, structural destabilization of the SOD architecture can lead to disease, as mutations in Cu,ZnSOD may result in familial amyotrophic lateral sclerosis, a relatively common, rapidly progressing and fatal neurodegenerative disorder. We describe our current understanding of how these Cu,ZnSOD mutations may lead to aggregation/fibril formation, as a detailed understanding of these mechanisms provides new avenues for the development of therapeutics against this so far untreatable neurodegenerative pathology. PMID:19914407

  14. Scavenging of superoxide anions by lecithinized superoxide dismutase in HL-60 cells.

    PubMed

    Ishihara, Tsutomu; Shibui, Misaki; Hoshi, Takaya; Mizushima, Tohru

    2016-01-01

    Superoxide dismutase covalently bound to four lecithin molecules (PC-SOD) has been found to have beneficial therapeutic effects in animal models of various diseases. However, the mechanism underlying these improved therapeutic effects has not yet been elucidated. It has previously been shown that PC-SOD localizes on the plasma membrane and in the lysosomes of cells. In this study, we evaluated the superoxide anion-scavenging activity of PC-SOD in HL-60 human promyelocytic leukemia cells. Compared to SOD, PC-SOD had only 17% scavenging activity in cell-free systems. Nevertheless, by analyzing enzyme activities in cell suspensions containing PC-SOD or SOD, PC-SOD and SOD showed almost equal activity for scavenging extracellular superoxide anions produced by HL-60 cells. Furthermore, the activity for scavenging extracellular superoxide anions increased with increased amount of PC-SOD on the plasma membrane. Moreover, PC-SOD exhibited no obvious inhibitory effect on the scavenging of intracellular superoxide anions. These results suggested that the association of PC-SOD with the plasma membrane plays a key role in its beneficial therapeutic effects. Thus, this finding may provide a rationale for selecting target diseases for PC-SOD treatment.

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

    SciTech Connect

    Teixeira, Miguel; Cabelli, Diane; Pinto, Ana F.; Romao, Celia V.; Pinto, Liliana C.; Huber, Harald; Saraiva, Ligia M.; Todorovic, Smilja

    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 is 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.

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

    DOE PAGES

    Teixeira, Miguel; Cabelli, Diane; Pinto, Ana F.; Romao, Celia V.; Pinto, Liliana C.; Huber, Harald; Saraiva, Ligia M.; Todorovic, Smilja

    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

  17. Chemical reactivity and biological effects of superoxide radicals

    NASA Astrophysics Data System (ADS)

    Chuaqui, C. A.; Petkau, A.

    The chemical reactivity of the superoxide radical is described in terms of its dismutation to oxygen, its basicity and ability to act as a nucleophile in aprotic media, and in its capacity to mediate one electron transfer reactions and undergo conversion to other species of active oxygen. The biological role of the superoxide radical is discussed in terms of its diffusion and reactivity within membranes, its potential to inactivate enzymes and elicit DNA damage in human granulocytes activated by phorbol esters. Mechanisms for reduction of oxygen to the superoxide radical by riboflavin, nitroaromatic compounds, nitrofurazone and oxazolinone are described. Finally, inactivation of bone marrow progenitor cells by superoxide radicals generated photochemically is discussed to emphasize the sensitizing effect of the medium, the sequential toxicity of superoxide and hydrogen peroxide, and the protective effects of superoxide dismutase and catalase while acting in their respective time frames.

  18. Scavenging of superoxide anion radical by chaparral.

    PubMed

    Zang, L Y; Cosma, G; Gardner, H; Starks, K; Shi, X; Vallyathan, V

    1999-06-01

    Chaparral is considered to act as an antioxidant. However, the inhibitory effects of chaparral on specific radical species are not well understood. Using electron paramagnetic resonance (EPR) spectroscopy in combination with spin trapping techniques, we have found that chaparral scavenges superoxide anion radical (O2*-) in a dose-dependent manner. 5,5-dimethyl-lpyrroline-N-oxide (DMPO) was used as a spin trapping agent and the reaction of xanthine and xanthine oxidase as a source of O2*-. The kinetic parameters, IC50 and Vmax, for chaparral scavenging of O2*- were found to be 0.899 microg/mL and 8.4 ng/mL/sec, respectively. The rate constant for chaparral scavenging O2*- was found to be 1.22 x 10(6) g(-1) s(-1). Our studies suggest that the antioxidant properties of chaparral may involve a direct scavenging effect of the primary oxygen radical, O2*-.

  19. Superoxide Free Radicals Are Produced in Glyoxysomes 1

    PubMed Central

    Sandalio, Luisa M.; Fernández, Victor M.; Rupérez, Francisco L.; Del Río, Luis A.

    1988-01-01

    The production of superoxide free radicals in pellet and supernatant fractions of glyoxysomes, specialized plant peroxisomes from watermelon (Citrullus vulgaris Schrad.) cotyledons, was investigated. Upon inhibition of the endogenous superoxide dismutase, xanthine, and hypoxanthine induced in glyoxysomal supernatants the generation of O2− radicals and this was inhibited by allopurinol. In glyoxysomal pellets, NADH stimulated the generation of superoxide radicals. Superoxide production by purines was due to xanthine oxidase, which was found predominantly in the matrix of glyoxysomes. The generation of O2− radicals in glyoxysomes by endogenous metabolites suggests new active oxygen-related roles for glyoxysomes, and for peroxisomes in general, in cellular metabolism. PMID:16666081

  20. Superoxide-dependent oxidation of melatonin by myeloperoxidase.

    PubMed

    Ximenes, Valdecir F; Silva, Sueli de O; Rodrigues, Maria R; Catalani, Luiz H; Maghzal, Ghassan J; Kettle, Anthony J; Campa, Ana

    2005-11-18

    Myeloperoxidase uses hydrogen peroxide to oxidize numerous substrates to hypohalous acids or reactive free radicals. Here we show that neutrophils oxidize melatonin to N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK) in a reaction that is catalyzed by myeloperoxidase. Production of AFMK was highly dependent on superoxide but not hydrogen peroxide. It did not require hypochlorous acid, singlet oxygen, or hydroxyl radical. Purified myeloperoxidase and a superoxide-generating system oxidized melatonin to AFMK and a dimer. The dimer would result from coupling of melatonin radicals. Oxidation of melatonin was partially inhibited by catalase or superoxide dismutase. Formation of AFMK was almost completely eliminated by superoxide dismutase but weakly inhibited by catalase. In contrast, production of melatonin dimer was enhanced by superoxide dismutase and blocked by catalase. We propose that myeloperoxidase uses superoxide to oxidize melatonin by two distinct pathways. One pathway involves the classical peroxidation mechanism in which hydrogen peroxide is used to oxidize melatonin to radicals. Superoxide adds to these radicals to form an unstable peroxide that decays to AFMK. In the other pathway, myeloperoxidase uses superoxide to insert dioxygen into melatonin to form AFMK. This novel activity expands the types of oxidative reactions myeloperoxidase can catalyze. It should be relevant to the way neutrophils use superoxide to kill bacteria and how they metabolize xenobiotics. PMID:16148002

  1. A mitochondrial superoxide theory for oxidative stress diseases and aging.

    PubMed

    Indo, Hiroko P; Yen, Hsiu-Chuan; Nakanishi, Ikuo; Matsumoto, Ken-Ichiro; Tamura, Masato; Nagano, Yumiko; Matsui, Hirofumi; Gusev, Oleg; Cornette, Richard; Okuda, Takashi; Minamiyama, Yukiko; Ichikawa, Hiroshi; Suenaga, Shigeaki; Oki, Misato; Sato, Tsuyoshi; Ozawa, Toshihiko; Clair, Daret K St; Majima, Hideyuki J

    2015-01-01

    Fridovich identified CuZnSOD in 1969 and manganese superoxide dismutase (MnSOD) in 1973, and proposed "the Superoxide Theory," which postulates that superoxide (O2 (•-)) is the origin of most reactive oxygen species (ROS) and that it undergoes a chain reaction in a cell, playing a central role in the ROS producing system. Increased oxidative stress on an organism causes damage to cells, the smallest constituent unit of an organism, which can lead to the onset of a variety of chronic diseases, such as Alzheimer's, Parkinson's, amyotrophic lateral sclerosis and other neurological diseases caused by abnormalities in biological defenses or increased intracellular reactive oxygen levels. Oxidative stress also plays a role in aging. Antioxidant systems, including non-enzyme low-molecular-weight antioxidants (such as, vitamins A, C and E, polyphenols, glutathione, and coenzyme Q10) and antioxidant enzymes, fight against oxidants in cells. Superoxide is considered to be a major factor in oxidant toxicity, and mitochondrial MnSOD enzymes constitute an essential defense against superoxide. Mitochondria are the major source of superoxide. The reaction of superoxide generated from mitochondria with nitric oxide is faster than SOD catalyzed reaction, and produces peroxynitrite. Thus, based on research conducted after Fridovich's seminal studies, we now propose a modified superoxide theory; i.e., superoxide is the origin of reactive oxygen and nitrogen species (RONS) and, as such, causes various redox related diseases and aging.

  2. Biomimetic superoxide dismutase stabilized by photopolymerization for superoxide anions biosensing and cell monitoring.

    PubMed

    Yuan, Ling; Liu, Suli; Tu, Wenwen; Zhang, Zengsong; Bao, Jianchun; Dai, Zhihui

    2014-05-20

    Photopolymerization strategy, as one of the immobilization methods, has attracted considerable interest because of some advantages, such as easy operation, harmlessness to the biomolecules, and long storage stability. (E)-4-(4-Formylstyryl) pyridine (formylstyrylpyridine) was prepared through Heck reaction and used as a photopolymer material to immobilize biomimetic superoxide dismutase under ultraviolet irradiation (UV) irradiation in a short time. The styrylpyridinium moiety of Formylstyrylpyridine was photoreactive and formed a dimer under UV irradiation. Mn2P2O7 multilayer sheet, a novel superoxide dismutase mimic, was synthesized. The formed photopolymer can immobilize Mn2P2O7 firmly under UV irradiation. On the basis of high catalytic activity of Mn2P2O7 biomimetic enzyme and long-term stability of Mn2P2O7-formylstyrylpyridine film, after introducing multiwalled carbon nanotubes (MWCNTs), a novel electrochemical biosensing platform called MWCNTs/Mn2P2O7-formylstyrylpyridine for superoxide anion (O2(•-)) detection was constructed. The biosensor displayed good performance for O2(•-) detection and provided a reliable platform to adhere living cells directly on the modified electrode surface. Therefore, the biosensor was successfully applied to vitro determination of O2(•-) released from living cells, which had a promising prospect for living cells monitoring and diagnosis of reactive oxygen species-related diseases.

  3. Superoxide Anion Production by Human Neutrophils Activated by Trichomonas vaginalis

    PubMed Central

    Song, Hyun-Ouk

    2013-01-01

    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. PMID:24039294

  4. 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. PMID:24039294

  5. 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.

  6. Manganese Superoxide Dismutase: Guardian of the Powerhouse

    PubMed Central

    Holley, Aaron K.; Bakthavatchalu, Vasudevan; Velez-Roman, Joyce M.; St. Clair, Daret K.

    2011-01-01

    The mitochondrion is vital for many metabolic pathways in the cell, contributing all or important constituent enzymes for diverse functions such as β-oxidation of fatty acids, the urea cycle, the citric acid cycle, and ATP synthesis. The mitochondrion is also a major site of reactive oxygen species (ROS) production in the cell. Aberrant production of mitochondrial ROS can have dramatic effects on cellular function, in part, due to oxidative modification of key metabolic proteins localized in the mitochondrion. The cell is equipped with myriad antioxidant enzyme systems to combat deleterious ROS production in mitochondria, with the mitochondrial antioxidant enzyme manganese superoxide dismutase (MnSOD) acting as the chief ROS scavenging enzyme in the cell. Factors that affect the expression and/or the activity of MnSOD, resulting in diminished antioxidant capacity of the cell, can have extraordinary consequences on the overall health of the cell by altering mitochondrial metabolic function, leading to the development and progression of numerous diseases. A better understanding of the mechanisms by which MnSOD protects cells from the harmful effects of overproduction of ROS, in particular, the effects of ROS on mitochondrial metabolic enzymes, may contribute to the development of novel treatments for various diseases in which ROS are an important component. PMID:22072939

  7. Superoxide Ion: Generation and Chemical Implications.

    PubMed

    Hayyan, Maan; Hashim, Mohd Ali; AlNashef, Inas M

    2016-03-01

    Superoxide ion (O2(•-)) is of great significance as a radical species implicated in diverse chemical and biological systems. However, the chemistry knowledge of O2(•-) is rather scarce. In addition, numerous studies on O2(•-) were conducted within the latter half of the 20th century. Therefore, the current advancement in technology and instrumentation will certainly provide better insights into mechanisms and products of O2(•-) reactions and thus will result in new findings. This review emphasizes the state-of-the-art research on O2(•-) so as to enable researchers to venture into future research. It comprises the main characteristics of O2(•-) followed by generation methods. The reaction types of O2(•-) are reviewed, and its potential applications including the destruction of hazardous chemicals, synthesis of organic compounds, and many other applications are highlighted. The O2(•-) environmental chemistry is also discussed. The detection methods of O2(•-) are categorized and elaborated. Special attention is given to the feasibility of using ionic liquids as media for O2(•-), addressing the latest progress of generation and applications. The effect of electrodes on the O2(•-) electrochemical generation is reviewed. Finally, some remarks and future perspectives are concluded.

  8. Manganese superoxide dismutase: beyond life and death

    PubMed Central

    Holley, Aaron K.; Dhar, Sanjit Kumar; Xu, Yong

    2010-01-01

    Manganese superoxide dismutase (MnSOD) is a nuclear-encoded antioxidant enzyme that localizes to the mitochondria. Expression of MnSOD is essential for the survival of aerobic life. Transgenic mice expressing a luciferase reporter gene under the control of the human MnSOD promoter demonstrate that the level of MnSOD is reduced prior to the formation of cancer. Overexpression of MnSOD in transgenic mice reduces the incidences and multiplicity of papillomas in a DMBA/TPA skin carcinogenesis model. However, MnSOD deficiency does not lead to enhanced tumorigenicity of skin tissue similarly treated because MnSOD can modulate both the p53-mediated apoptosis and AP-1-mediated cell proliferation pathways. Apoptosis is associated with an increase in mitochondrial levels of p53 suggesting a link between MnSOD deficiency and mitochondrial-mediated apoptosis. Activation of p53 is preventable by application of a SOD mimetic (MnTE-2-PyP5+). Thus, p53 translocation to mitochondria and subsequent inactivation of MnSOD explain the observed mitochondrial dysfunction that leads to transcription-dependent mechanisms of p53-induced apoptosis. Administration of MnTE-2-PyP5+ following apoptosis but prior to proliferation leads to suppression of protein carbonyls and reduces the activity of AP-1 and the level of the proliferating cellular nuclear antigen, without reducing the activity of p53 or DNA fragmentation following TPA treatment. Remarkably, the incidence and multiplicity of skin tumors are drastically reduced in mice that receive MnTE-2-PyP5+ prior to cell proliferation. The results demonstrate the role of MnSOD beyond its essential role for survival and suggest a novel strategy for an antioxidant approach to cancer intervention. PMID:20454814

  9. Mitochondrial Flashes: Dump Superoxide and Dance with Protons Now.

    PubMed

    Demaurex, Nicolas; Schwarzländer, Markus

    2016-09-20

    Transient changes in the physiology of individual mitochondria have recently drawn much interest. The use of a circular permuted yellow fluorescent protein (cpYFP) to monitor mitochondrial flashes and their interpretation as superoxide bursts has added confusion, however. Reviewing mitochondrial flashes in this Forum, Wang et al. again deem cpYFP to be a specific and reversible superoxide indicator, dismissing evidence that purified cpYFP is insensitive to superoxide. This interpretation lacks reproducible evidence and conflicts with the parsimony principle. We offer a constructive, transparent pathway to reach definitive clarification of contradictory reports. Antioxid. Redox Signal. 25, 550-551. PMID:27400996

  10. Mitochondrial Flashes: Dump Superoxide and Dance with Protons Now

    PubMed Central

    2016-01-01

    Abstract Transient changes in the physiology of individual mitochondria have recently drawn much interest. The use of a circular permuted yellow fluorescent protein (cpYFP) to monitor mitochondrial flashes and their interpretation as superoxide bursts has added confusion, however. Reviewing mitochondrial flashes in this Forum, Wang et al. again deem cpYFP to be a specific and reversible superoxide indicator, dismissing evidence that purified cpYFP is insensitive to superoxide. This interpretation lacks reproducible evidence and conflicts with the parsimony principle. We offer a constructive, transparent pathway to reach definitive clarification of contradictory reports. Antioxid. Redox Signal. 25, 550–551. PMID:27400996

  11. Negative air ions as a source of superoxide

    NASA Astrophysics Data System (ADS)

    Goldstein, Naum I.; Goldstein, Roman N.; Merzlyak, Mark N.

    1992-06-01

    The physico-chemical characteristics and possible formation mechanisms of negative air ions are considered. It was found that the products of oxygen and nitrogen negative ionization reduce ferricytochrome c and nitroblue tetrazolium, and that these reactions were inhibited by superoxide dismutase. The interaction of negatively ionized oxygen with water led to hydrogen peroxide accumulation, which was inhibited by tetranitromethane or catalase. Nitrogen ionization under these conditions caused the formation of the hydrated electron e{aq/—} and the superoxide anion O{2/—}. The data obtained indicate that the biological activity of negative air ions may be dependent on superoxide. The generation of reactive oxygen ions in the gas phase and also at a gas/water interface is described. A scheme for superoxide production under oxygen and nitrogen ionization is proposed.

  12. Antioxidative activity of ginkgolides against superoxide in an aprotic environment.

    PubMed

    Scholtyssek, H; Damerau, W; Wessel, R; Schimke, I

    1997-10-24

    The terpene lactones ginkgolide A, ginkgolide B, ginkgolide C, ginkgolide J and bilobalide, which are components of a standardized extract (EGb 761) from leaves of Ginkgo biloba, as well as ginkgolide M from roots of G. biloba were studied regarding their reaction against superoxide (O2-) and hydroperoxyl radicals (HO2) in dimethyl sulfoxide as an aprotic solvent. It was found that the ginkgolides B, C, J, M as well as bilobalide react with superoxide and its protonated form as demonstrated by EPR and UV/VIS spectroscopy. The initial reaction rate with these oxygen-derived radicals is in the order of 100 M-1/s and below. Ginkgolide A does not react with superoxide under these conditions. From these findings it can be suggested that the superoxide scavenging effect of the ginkgolides B, C, J, M and bilobalide contributes to the antioxidant properties of G. biloba. PMID:9413545

  13. Suppressors of superoxide production from mitochondrial complex III.

    PubMed

    Orr, Adam L; Vargas, Leonardo; Turk, Carolina N; Baaten, Janine E; Matzen, Jason T; Dardov, Victoria J; Attle, Stephen J; Li, Jing; Quackenbush, Douglas C; Goncalves, Renata L S; Perevoshchikova, Irina V; Petrassi, H Michael; Meeusen, Shelly L; Ainscow, Edward K; Brand, Martin D

    2015-11-01

    Mitochondrial electron transport drives ATP synthesis but also generates reactive oxygen species, which are both cellular signals and damaging oxidants. Superoxide production by respiratory complex III is implicated in diverse signaling events and pathologies, but its role remains controversial. Using high-throughput screening, we identified compounds that selectively eliminate superoxide production by complex III without altering oxidative phosphorylation; they modulate retrograde signaling including cellular responses to hypoxic and oxidative stress.

  14. Suppressors of superoxide production from mitochondrial complex III

    PubMed Central

    Orr, Adam L.; Vargas, Leonardo; Turk, Carolina N.; Baaten, Janine E.; Matzen, Jason T.; Dardov, Victoria J.; Attle, Stephen J.; Li, Jing; Quackenbush, Douglas C.; Goncalves, Renata L. S.; Perevoshchikova, Irina V.; Petrassi, H. Michael; Meeusen, Shelly L.; Ainscow, Edward K.; Brand, Martin D.

    2015-01-01

    Mitochondrial electron transport drives ATP synthesis but also generates reactive oxygen species (ROS), which are both cellular signals and damaging oxidants. Superoxide production by respiratory complex III is implicated in diverse signaling events and pathologies but its role remains controversial. Using high-throughput screening we identified compounds that selectively eliminate superoxide production by complex III without altering oxidative phosphorylation; they modulate retrograde signaling including cellular responses to hypoxic and oxidative stress. PMID:26368590

  15. Regulation of superoxide dismutase synthesis in Escherichia coli: glucose effect.

    PubMed Central

    Moustafa Hassan, H; Fridovich, I

    1977-01-01

    Growth of Escherichia coli, based upon the fermentation of glucose, is associated with a low intracellular level of superoxide dismutase. Exhaustion of glucose, or depression of the pH due to accumulation of organic acids, causes these organisms to then obtain energy from the oxidative degradation of other substances present in a rich medium. This shift in metabolism is associated with a marked increase in the rate of synthesis of superoxide dismutase. Depression of the synthesis of superoxide dismutase by glucose is not due to catabolite repression since it is not eliminated by cyclic adenosine 3',5'-monophosphate and since alpha-methyl glucoside does not mimic the effect of glucose. Moreover, glucose itself no longer depresses superoxide dismutase synthesis when the pH has fallen low enough to cause a shift to a non-fermentative metabolism. It appears likely that superoxide dismutase is controlled directly or indirectly by the intracellular level of O2- and that glucose depressed the level of this enzyme because glucose metabolism is not associated with as rapid a production of O2- as is the metabolsim of many other substances. In accord with this view is the observation that paraquat, which can increase the rate of production of O2- by redox cycling, caused a rapid and marked increase in superoxide dismutase. PMID:21164

  16. 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.

  17. Superoxide Dismutase and Oxygen Toxicity in a Eukaryote

    PubMed Central

    Gregory, Eugene M.; Goscin, Stephen A.; Fridovich, Irwin

    1974-01-01

    Saccharomyces cerevisiae var. ellipsoideus contained 6.5 times more superoxide dismutase and 2.3 times more catalase when grown under 100% O2 than when grown anaerobically. Growth under oxygen caused equal increases in both the cyanide-sensitive and the cyanide-insensitive superoxide dismutases of this organism. Experience with other eukaryotes has shown that cyanide sensitivity is a property of the cupro-zinc superoxide dismutase of the cytosol, whereas cyanide insensitivity is a property of the corresponding mangani-enzyme found in mitochondria. Cu2+, which has been shown to increase the radioresistance of yeast, also caused an increase of both of the superoxide dismutases of S. cerevisiae. Yeast which had been grown under 1 atm of O2 were more resistant toward the lethal effects of 20 atm of O2 than were yeast which had been grown in the absence of O2. Escherichia coli K-12 his− responded to growth under 1 atm of O2 by increasing its content of catalase and of peroxidase, but not of superoxide dismutase. This contrasts with E. coli B, which was previously shown to respond to O2 by a striking increase in superoxide dismutase. E. coli K-12 his− did not gain resistance toward 20 atm of O2 because of having been grown under 1 atm of O2. Once again, this contrasts with the behavior of E. coli B. These data indicate that, in both prokaryotes and in eukaryotes, superoxide dismutase is an important component of the defenses against oxygen toxicity. PMID:4590469

  18. Characterization of superoxide production by isolated pea thylakoids

    SciTech Connect

    Grace, S.; Osmond, B. )

    1991-05-01

    During photosynthesis chloroplasts univalently reduce molecular oxygen to superoxide through autoxidations in the electron transport chain. Cytochrome c reduction was used to assay superoxide production in illuminate pea thylakoids under a variety of conditions. Superoxide dismutase was found to inhibit the reaction by 80%, indicating that cytochrome c reduction is primarily mediated by superoxide. This was further supported by the observation that the highest rates of cytochrome c reduction occurred in the presence of methyl viologen, an autoxidizable redox carrier that accepts electrons from photosystem I. The reaction was fully suppressed by DCMU, demonstrating a requirement for electron transport. In the presence of the plastoquinone antagonist DBMIB the rate of cytochrome c reduction increased substantially. This indicates that under conditions where electron transport to photosystem I is blocked, autoxidation reactions can occur on the reducing side of photosystem II to maintain Q{sub A} in the oxidized state. Superoxide production at sites other than the reducing side of photosystem I may thus represent an important pathway for dissipating excess excitation energy.

  19. The superoxide reductase from the early diverging eukaryote Giardia intestinalis.

    PubMed

    Testa, Fabrizio; Mastronicola, Daniela; Cabelli, Diane E; Bordi, Eugenio; Pucillo, Leopoldo P; Sarti, Paolo; Saraiva, Lígia M; Giuffrè, Alessandro; Teixeira, Miguel

    2011-10-15

    Unlike superoxide dismutases (SODs), superoxide reductases (SORs) eliminate superoxide anion (O(2)(•-)) not through its dismutation, but via reduction to hydrogen peroxide (H(2)O(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(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), yields a resting species (T(final)) with Fe(3+) ligated to glutamate or hydroxide depending on pH (apparent pK(a)=8.7). Although showing negligible SOD activity, reduced SOR(Gi) reacts with O(2)(•-) with a pH-independent second-order rate constant k(1)=1.0×10(9) M(-1) s(-1) and yields the ferric-(hydro)peroxo intermediate T(1); this in turn rapidly decays to the T(final) state with pH-dependent rates, without populating other detectable intermediates. Immunoblotting assays show that SOR(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.

  20. Formation of manganese oxides by bacterially generated superoxide

    NASA Astrophysics Data System (ADS)

    Learman, D. R.; Voelker, B. M.; Vazquez-Rodriguez, A. I.; Hansel, C. M.

    2011-02-01

    Manganese oxide minerals are among the strongest sorbents and oxidants in the environment. The formation of these minerals controls the fate of contaminants, the degradation of recalcitrant carbon, the cycling of nutrients and the activity of anaerobic-based metabolisms. Oxidation of soluble manganese(II) ions to manganese(III/IV) oxides has been primarily attributed to direct enzymatic oxidation by microorganisms. However, the physiological reason for this process remains unknown. Here we assess the ability of a common species of marine bacteria-Roseobacter sp. AzwK-3b-to oxidize manganese(II) in the presence of chemical and biological inhibitors. We show that Roseobacter AzwK-3b oxidizes manganese(II) by producing the strong and versatile redox reactant superoxide. The oxidation of manganese(II), and concomitant production of manganese oxides, was inhibited in both the light and dark in the presence of enzymes and metals that scavenge superoxide. Oxidation was also inhibited by various proteases, enzymes that break down bacterial proteins, confirming that the superoxide was bacterially generated. We conclude that bacteria can oxidize manganese(II) indirectly, through the enzymatic generation of extracellular superoxide radicals. We suggest that dark bacterial production of superoxide may be a driving force in metal cycling and mineralization in the environment.

  1. The Role of Manganese Superoxide Dismutase in Inflammation Defense

    PubMed Central

    Li, Chang; Zhou, Hai-Meng

    2011-01-01

    Antioxidant enzymes maintain cellular redox homeostasis. Manganese superoxide dismutase (MnSOD), an enzyme located in mitochondria, is the key enzyme that protects the energy-generating mitochondria from oxidative damage. Levels of MnSOD are reduced in many diseases, including cancer, neurodegenerative diseases, and psoriasis. Overexpression of MnSOD in tumor cells can significantly attenuate the malignant phenotype. Past studies have reported that this enzyme has the potential to be used as an anti-inflammatory agent because of its superoxide anion scavenging ability. Superoxide anions have a proinflammatory role in many diseases. Treatment of a rat model of lung pleurisy with the MnSOD mimetic MnTBAP suppressed the inflammatory response in a dose-dependent manner. In this paper, the mechanisms underlying the suppressive effects of MnSOD in inflammatory diseases are studied, and the potential applications of this enzyme and its mimetics as anti-inflammatory agents are discussed. PMID:21977313

  2. 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

  3. Theoretical study of the superoxide anion assisted firefly oxyluciferin formation

    NASA Astrophysics Data System (ADS)

    Pinto da Silva, Luís; Esteves da Silva, Joaquim C. G.

    2013-12-01

    This a theoretical Letter based on density functional theory, on the role of superoxide anion in firefly chemiluminescence in DMSO. We have found that this anion can attack luciferin radical molecules, thus forming a luciferin-like trianion. This latter molecule transfers an oxygen atom, which results in the formation of oxyluciferyl radical dianion and carbon dioxide molecules. Oxyluciferin is finally formed after an electron transfer from oxyluciferyl radical dianion to tert-BuOrad radical molecules. Thus, we have found evidence that firefly oxyluciferin can be formed in a energetically favorable superoxide anion-assisted reaction, without the need for the formation of firefly dioxetanone.

  4. Chemical and physical differentiation of superoxide dismutases in anaerobes.

    PubMed Central

    Gregory, E M; Dapper, C H

    1980-01-01

    Superoxide dismutase activity in crude or partially purified cell extracts from several species and strains of obligate anaerobe Bacteroides was inhibited instantaneously by NaN3 and was inactivated rapidly upon incubation with H2O2. The extent of NaN3 inhibition varied from 41 to 93%, and the half-life of the enzymatic activity in 5 mM H2O2 ranged from 1.2 to 6.1 min, depending upon the organism tests. When grown in a defined medium containing 59Fe, Bacteroides fragilis (VPI 2393) incorporated radiolabel into a 40,000-molecular-weight NaN3- and H2O2-sensitive superoxide dismutase but did not incorporate 54Mn into that protein under similar growth conditions. The anaerobe Actinomyces naeslundii (VPI 9985) incorporated 54Mn but not 59Fe into a NaN3-insensitive and H2O2-resistant superoxide dismutase. The apparent molecular weight of the superoxide dismutase from this and several other Actinomyces spp. was estimated to be 110,000 to 140,000. Comparison of these data with studies of homogeneous metallosuperoxide dismutases suggests that the Bacteroides spp. studied contain a ferrisuperoxide dismutase, whereas Actinomyces spp. contain a managanisuperoxide dismutase. PMID:7440509

  5. Generation of superoxide by the mitochondrial Complex I.

    PubMed

    Grivennikova, Vera G; Vinogradov, Andrei D

    2006-01-01

    Superoxide production by inside-out coupled bovine heart submitochondrial particles, respiring with succinate or NADH, was measured. The succinate-supported production was inhibited by rotenone and uncouplers, showing that most part of superoxide produced during succinate oxidation is originated from univalent oxygen reduction by Complex I. The rate of the superoxide (O2*-)) production during respiration at a high concentration of NADH (1 mM) was significantly lower than that with succinate. Moreover, the succinate-supported O2*- production was significantly decreased in the presence of 1 mM NADH. The titration curves, i.e., initial rates of superoxide production versus NADH concentration, were bell-shaped with the maximal rate (at 50 microM NADH) approaching that seen with succinate. Both NAD+ and acetyl-NAD+ inhibited the succinate-supported reaction with apparent Ki's close to their Km's in the Complex I-catalyzed succinate-dependent energy-linked NAD+ reduction (reverse electron transfer) and NADH:acetyl-NAD+ transhydrogenase reaction, respectively. We conclude that: (i) under the artificial experimental conditions the major part of superoxide produced by the respiratory chain is formed by some redox component of Complex I (most likely FMN in its reduced or free radical form); (ii) two different binding sites for NADH (F-site) and NAD+ (R-site) in Complex I provide accessibility of the substrates-nucleotides to the enzyme red-ox component(s); F-site operates as an entry for NADH oxidation, whereas R-site operates in the reverse electron transfer and univalent oxygen reduction; (iii) it is unlikely that under the physiological conditions (high concentrations of NADH and NAD+) Complex I is responsible for the mitochondrial superoxide generation. We propose that the specific NAD(P)H:oxygen superoxide (hydrogen peroxide) producing oxidoreductase(s) poised in equilibrium with NAD(P)H/NAD(P)+ couple should exist in the mitochondrial matrix, if mitochondria are

  6. Therapeutic effect of lecithinized superoxide dismutase on pulmonary emphysema.

    PubMed

    Tanaka, Ken-Ichiro; Tanaka, Yuta; Miyazaki, Yuri; Namba, Takushi; Sato, Keizo; Aoshiba, Kazutetsu; Azuma, Arata; Mizushima, Tohru

    2011-09-01

    No medication exists that clearly improves the mortality of chronic obstructive pulmonary disease (COPD). Oxidative molecules, in particular superoxide anions, play important roles in the COPD-associated abnormal inflammatory response and pulmonary emphysema, which arises because of an imbalance in proteases and antiproteases and increased apoptosis. Superoxide dismutase (SOD) catalyzes the dismutation of superoxide anions. Lecithinized human Cu/Zn- SOD (PC-SOD) has overcome a number of the clinical limitations of SOD, including low tissue affinity and low stability in plasma. In this study, we examine the effect of PC-SOD on elastase-induced pulmonary emphysema, an animal model of COPD. The severity of the pulmonary inflammatory response and emphysema in mice was assessed by various criteria, such as the number of leukocytes in the bronchoalveolar lavage fluid and the enlargement of airspace. Not only intravenous administration but also inhalation of PC-SOD suppressed elastase-induced pulmonary inflammation, emphysema, and dysfunction. Inhalation of PC-SOD suppressed the elastase-induced increase in the pulmonary level of superoxide anions and apoptosis. Inhalation of PC-SOD also suppressed elastase-induced activation of proteases and decreased in the level of antiproteases and expression of proinflammatory cytokines and chemokines. We also found that inhalation of PC-SOD suppressed cigarette smoke-induced pulmonary inflammation. The results suggest that PC-SOD protects against pulmonary emphysema by decreasing the pulmonary level of superoxide anions, resulting in the inhibition of inflammation and apoptosis and amelioration of the protease/antiprotease imbalance. We propose that inhalation of PC-SOD would be therapeutically beneficial for COPD.

  7. Real time monitoring of superoxide dynamics in vivo through fluorescent proteins using a sensitive fiber probe

    NASA Astrophysics Data System (ADS)

    Chang, Yu-Chung; Ken, Chuian-Fu; Hsu, Che-Wei; Liu, Ya-Ging

    2014-03-01

    Superoxide anion is the primary oxygen free radical generated in mitochondria that causes intracellular oxidative stress. The lack of a method to directly monitor superoxide concentration in vivo in real time has severely hindered our understanding on its pathophysiology. We made transgenic zebrafish to specifically express fluorescent proteins, which are recently developed as reversible superoxide-specific indicators, in the liver. A fiber-optic fluorescent probe was used to noninvasively monitor superoxide generation in the liver in real time. The fish were placed in microfluidic channels for manipulation and reagents administration. Several superoxide-inducing and scavenging reagents were administrated onto the fish to investigate their effects on superoxide anion balancing. The biochemical dynamics of superoxide due to the application reagents were revealed in the transient behaviors of fluorescence time courses. With the ability to monitor superoxide dynamics in vivo in real time, this method can be used as an in vivo pharmaceutical screening platform.

  8. Extracellular Superoxide Dismutase: Growth Promoter or Tumor Suppressor?

    PubMed Central

    Laukkanen, Mikko O.

    2016-01-01

    Extracellular superoxide dismutase (SOD3) gene transfer to tissue damage results in increased healing, increased cell proliferation, decreased apoptosis, and decreased inflammatory cell infiltration. At molecular level, in vivo SOD3 overexpression reduces superoxide anion (O2−) concentration and increases mitogen kinase activation suggesting that SOD3 could have life-supporting characteristics. The hypothesis is further strengthened by the observations showing significantly increased mortality in conditional knockout mice. However, in cancer SOD3 has been shown to either increase or decrease cell proliferation and survival depending on the model system used, indicating that SOD3-derived growth mechanisms are not completely understood. In this paper, the author reviews the main discoveries in SOD3-dependent growth regulation and signal transduction. PMID:27293512

  9. Extracellular Superoxide Dismutase: Growth Promoter or Tumor Suppressor?

    PubMed

    Laukkanen, Mikko O

    2016-01-01

    Extracellular superoxide dismutase (SOD3) gene transfer to tissue damage results in increased healing, increased cell proliferation, decreased apoptosis, and decreased inflammatory cell infiltration. At molecular level, in vivo SOD3 overexpression reduces superoxide anion (O2 (-)) concentration and increases mitogen kinase activation suggesting that SOD3 could have life-supporting characteristics. The hypothesis is further strengthened by the observations showing significantly increased mortality in conditional knockout mice. However, in cancer SOD3 has been shown to either increase or decrease cell proliferation and survival depending on the model system used, indicating that SOD3-derived growth mechanisms are not completely understood. In this paper, the author reviews the main discoveries in SOD3-dependent growth regulation and signal transduction. PMID:27293512

  10. Cupric yersiniabactin is a virulence-associated superoxide dismutase mimic.

    PubMed

    Chaturvedi, Kaveri S; Hung, Chia S; Giblin, Daryl E; Urushidani, Saki; Austin, Anthony M; Dinauer, Mary C; Henderson, Jeffrey P

    2014-02-21

    Many Gram-negative bacteria interact with extracellular metal ions by expressing one or more siderophore types. Among these, the virulence-associated siderophore yersiniabactin (Ybt) is an avid copper chelator, forming stable cupric (Cu(II)-Ybt) complexes that are detectable in infected patients. Here we show that Ybt-expressing E. coli are protected from intracellular killing within copper-replete phagocytic cells. This survival advantage is highly dependent upon the phagocyte respiratory burst, during which superoxide is generated by the NADPH oxidase complex. Chemical fractionation links this phenotype to a previously unappreciated superoxide dismutase (SOD)-like activity of Cu(II)-Ybt. Unlike previously described synthetic copper-salicylate (Cu(II)-SA) SOD mimics, the salicylate-based natural product Cu(II)-Ybt retains catalytic activity at physiologically plausible protein concentrations. These results reveal a new virulence-associated adaptation based upon spontaneous assembly of a non-protein catalyst. PMID:24283977

  11. Cupric Yersiniabactin Is a Virulence-Associated Superoxide Dismutase Mimic

    PubMed Central

    2013-01-01

    Many Gram-negative bacteria interact with extracellular metal ions by expressing one or more siderophore types. Among these, the virulence-associated siderophore yersiniabactin (Ybt) is an avid copper chelator, forming stable cupric (Cu(II)-Ybt) complexes that are detectable in infected patients. Here we show that Ybt-expressing E. coli are protected from intracellular killing within copper-replete phagocytic cells. This survival advantage is highly dependent upon the phagocyte respiratory burst, during which superoxide is generated by the NADPH oxidase complex. Chemical fractionation links this phenotype to a previously unappreciated superoxide dismutase (SOD)-like activity of Cu(II)-Ybt. Unlike previously described synthetic copper-salicylate (Cu(II)-SA) SOD mimics, the salicylate-based natural product Cu(II)-Ybt retains catalytic activity at physiologically plausible protein concentrations. These results reveal a new virulence-associated adaptation based upon spontaneous assembly of a non-protein catalyst. PMID:24283977

  12. The Superoxide Reductase from the Early Diverging Eukaryote Giardia Intestinalis

    SciTech Connect

    Cabelli, D.E.; Testa, F.; Mastronicola, D.; Bordi, E.; Pucillo, L.P.; Sarti, P.; Saraiva, L.M.; Giuffre, A.; Teixeira, M.

    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), yields 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.

  13. A simplified hydroethidine method for fast and accurate detection of superoxide production in isolated mitochondria.

    PubMed

    Back, Patricia; Matthijssens, Filip; Vanfleteren, Jacques R; Braeckman, Bart P

    2012-04-01

    Because superoxide is involved in various physiological processes, many efforts have been made to improve its accurate quantification. We optimized and validated a superoxide-specific and -sensitive detection method. The protocol is based on fluorescence detection of the superoxide-specific hydroethidine (HE) oxidation product, 2-hydroxyethidium. We established a method for the quantification of superoxide production in isolated mitochondria without the need for acetone extraction and purification chromatography as described in previous studies.

  14. SORGOdb: Superoxide Reductase Gene Ontology curated DataBase

    PubMed Central

    2011-01-01

    Background Superoxide reductases (SOR) catalyse the reduction of superoxide anions to hydrogen peroxide and are involved in the oxidative stress defences of anaerobic and facultative anaerobic organisms. Genes encoding SOR were discovered recently and suffer from annotation problems. These genes, named sor, are short and the transfer of annotations from previously characterized neelaredoxin, desulfoferrodoxin, superoxide reductase and rubredoxin oxidase has been heterogeneous. Consequently, many sor remain anonymous or mis-annotated. Description SORGOdb is an exhaustive database of SOR that proposes a new classification based on domain architecture. SORGOdb supplies a simple user-friendly web-based database for retrieving and exploring relevant information about the proposed SOR families. The database can be queried using an organism name, a locus tag or phylogenetic criteria, and also offers sequence similarity searches using BlastP. Genes encoding SOR have been re-annotated in all available genome sequences (prokaryotic and eukaryotic (complete and in draft) genomes, updated in May 2010). Conclusions SORGOdb contains 325 non-redundant and curated SOR, from 274 organisms. It proposes a new classification of SOR into seven different classes and allows biologists to explore and analyze sor in order to establish correlations between the class of SOR and organism phenotypes. SORGOdb is freely available at http://sorgo.genouest.org/index.php. PMID:21575179

  15. Superoxide generation and cytotactic response of irradiated neutrophils

    SciTech Connect

    Eastlund, D.T.; Charbonneau, T.T.

    1988-07-01

    Irradiation of blood components has been used to prevent transfusion-related graft-versus-host disease (GVHD) in immunocompromised patients. This study was designed to determine the effect of irradiation on neutrophil aggregation, chemotaxis, and superoxide generation. Purified neutrophils were irradiated with a Cesium source at four doses ranging from 0 to 17,500 rads. Formyl-methionyl-leucyl-phenylalanine (FMLP) and zymosan-treated serum (ZTS) cytotaxin-induced chemotaxis and migration were determined in the agarose assay. Neutrophil aggregation to FMLP was determined by aggregometry. Superoxide generation and random migration were not affected by irradiation at doses up to 17,500 rads. When compared to nonirradiated controls, the chemotactic response to ZTS remained normal, with an insignificant decline from 174 +/- 31.0 to 150 +/- 42.3 (mean +/- SD) units. The chemotactic response to FMLP declined insignificantly, from 228 +/- 31.3 at 0 rad to 207 +/- 26.4 at 17,500 rads. The aggregation response to FMLP remained within the normal range but declined from 0.78 +/- 0.11 to 0.61 +/- 0.18. At the radiation doses currently used to reduce the risk of transfusion-related GVHD, neutrophil superoxide generation and chemotactic response remain essentially normal.

  16. Faropenem enhances superoxide anion production by human neutrophils in vitro.

    PubMed

    Sato, K; Sato, N; Shimizu, H; Tsutiya, T; Takahashi, H; Kakizaki, S; Takayama, H; Takagi, H; Mori, M

    1999-09-01

    Neutrophils are important cellular components in the defence against infections and many studies in vitro have shown that some antibiotics affect neutrophil function. We examined the effect of faropenem, a new oral penem antibiotic on neutrophil killing function by determining the generation of superoxide anion in vitro. The production of superoxide anion was measured by chemiluminescence amplified by a Cypridina luciferin analogue in the presence of N-formyl-Met-Leu-Phe (fMLP). Faropenem significantly enhanced chemiluminescence in a dose-dependent manner. The effect of faropenem was maximal at 5 min of incubation time and continued for at least 30 min. The effect of faropenem was also observed when neutrophils were stimulated by a calcium ionophore (ionomycin), while the effect of faropenem did not change in the presence of 12-O-tetra-decanoylphorbolmyristate acetate. Cytosol Ca2+ concentration ([Ca2+]i) monitored with Fura-2 increased in response to fMLP, however, faropenem did not influence the response of [Ca2+]i to fMLP. Our results suggest that faropenem enhanced the generation of superoxide anion by neutrophils, probably at the site where cytosol Ca2+ regulates NADPH oxidase. Faropenem might be potentially advantageous in the treatment of infections because a synergic interaction of antibodies and cytocidal neutrophils is necessary for the early eradication of the pathogenic bacteria. PMID:10511400

  17. Superoxide radical and iron modulate aconitase activity in mammalian cells.

    PubMed

    Gardner, P R; Raineri, I; Epstein, L B; White, C W

    1995-06-01

    Aconitase is a member of a family of iron-sulfur-containing (de)hydratases whose activities are modulated in bacteria by superoxide radical (O2-.)-mediated inactivation and iron-dependent reactivation. The inactivation-reactivation of aconitase(s) in cultured mammalian cells was explored since these reactions may impact important and diverse aconitase functions in the cytoplasm and mitochondria. Conditions which increase O2-. production including exposure to the redox-cycling agent phenazine methosulfate (PMS), inhibitors of mitochondrial ubiquinol-cytochrome c oxidoreductase, or hyperoxia inactivated aconitase in mammalian cells. Overproduction of mitochondrial Mn-superoxide dismutase protected aconitase from inactivation by PMS or inhibitors of ubiquinol-cytochrome c oxidoreductase, but not from normobaric hyperoxia. Aconitase activity was reactivated (t1/2 of 12 +/- 3 min) upon removal of PMS. The iron chelator deferoxamine impaired reactivation and increased net inactivation of aconitase by O2-.. The ability of ubiquinol-cytochrome c oxidoreductase-generated O2-. to inactivate aconitase in several cell types correlated with the fraction of the aconitase activity localized in mitochondria. Extracellular O2-. generated with xanthine oxidase did not affect aconitase activity nor did exogenous superoxide dismutase decrease aconitase inactivation by PMS. The results demonstrate a dynamic and cyclical O2-.-mediated inactivation and iron-dependent reactivation of the mammalian [4Fe-4S] aconitases under normal and stress conditions and provide further evidence for the membrane compartmentalization of O2-.. PMID:7768942

  18. A new method to prevent degradation of lithium-oxygen batteries: reduction of superoxide by viologen.

    PubMed

    Yang, L; Frith, J T; Garcia-Araez, N; Owen, J R

    2015-01-31

    Lithium-oxygen battery development is hampered by degradation reactions initiated by superoxide, which is formed in the pathway of oxygen reduction to peroxide. This work demonstrates that the superoxide lifetime is drastically decreased upon addition of ethyl viologen, which catalyses the reduction of superoxide to peroxide. PMID:25515175

  19. A mitochondrial superoxide signal triggers increased longevity in Caenorhabditis elegans.

    PubMed

    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

  20. Mechanical overloading causes mitochondrial superoxide and SOD2 imbalance in chondrocytes resulting in cartilage degeneration.

    PubMed

    Koike, Masato; Nojiri, Hidetoshi; Ozawa, Yusuke; Watanabe, Kenji; Muramatsu, Yuta; Kaneko, Haruka; Morikawa, Daichi; Kobayashi, Keiji; Saita, Yoshitomo; Sasho, Takahisa; Shirasawa, Takuji; Yokote, Koutaro; Kaneko, Kazuo; Shimizu, Takahiko

    2015-01-01

    Mechanical stress and aging are major risk factors of cartilage degeneration. Human studies have previously reported that oxidative damage increased, while SOD2 protein was reciprocally downregulated in osteoarthritic degenerated cartilage. However, it remains unclear whether mitochondrial superoxide imbalance in chondrocytes causes cartilage degeneration. We herein demonstrate that mechanical loading promoted mitochondrial superoxide generation and selective Sod2 downregulation in chondrocytes in vivo and that mitochondrial superoxide inducer also downregulated Sod2 expression in chondrocytes in vitro. A genetically manipulated model revealed that Sod2 deficiency in chondrocytes also resulted in mitochondrial superoxide overproduction and dysfunction, thus leading to cartilage degeneration. Intra-articular injection of a permeable antioxidant effectively suppressed the mechanical loading-induced mitochondrial superoxide generation and cartilage degeneration in mice. Our findings demonstrate that mitochondrial superoxide plays a pivotal role in the development and progression of osteoarthritis, and the mitochondrial superoxide balance may therefore be a promising target for the treatment of cartilage degeneration. PMID:26108578

  1. Cu,Zn Superoxide Dismutase is a Peroxisomal Enzyme in Human Fibroblast and Hepatoma Cells

    NASA Astrophysics Data System (ADS)

    Keller, Gilbert-Andre; Warner, Thomas G.; Steimer, Kathelyn S.; Hallewell, Robert A.

    1991-08-01

    The intracellular localization of Cu,Zn superoxide dismutase (superoxide:superoxide oxidoreductase, EC 1.15.1.1) has been examined by immunofluorescence using four monoclonal anti-Cu,Zn superoxide dismutase antibodies raised against a recombinant human Cu,Zn superoxide dismutase derivative produced and purified from Escherichia coli. Colocalization with catalase, a peroxisomal matrix enzyme, was used to demonstrate the peroxisomal localization of Cu,Zn superoxide dismutase in human fibroblasts and hepatoma cells. In the fibroblasts of Zellweger syndrome patients, the enzyme is not transported to the peroxisomal ghosts but, like catalase, remains in the cytoplasm. In addition, immunocryoelectron microscopy of yeast cells expressing human Cu,Zn superoxide dismutase showed that the enzyme is translocated to the peroxisomes.

  2. A lithium-oxygen battery based on lithium superoxide

    NASA Astrophysics Data System (ADS)

    Lu, Jun; Jung Lee, Yun; Luo, Xiangyi; Chun Lau, Kah; Asadi, Mohammad; Wang, Hsien-Hau; Brombosz, Scott; Wen, Jianguo; Zhai, Dengyun; Chen, Zonghai; Miller, Dean J.; Sub Jeong, Yo; Park, Jin-Bum; Zak Fang, Zhigang; Kumar, Bijandra; Salehi-Khojin, Amin; Sun, Yang-Kook; Curtiss, Larry A.; Amine, Khalil

    2016-01-01

    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.

  3. Redox properties of a mononuclear copper(II)-superoxide complex.

    PubMed

    Tano, Tetsuro; Okubo, Yuri; Kunishita, Atsushi; Kubo, Minoru; Sugimoto, Hideki; Fujieda, Nobutaka; Ogura, Takashi; Itoh, Shinobu

    2013-09-16

    Redox properties of a mononuclear copper(II) superoxide complex, (L)Cu(II)-OO(•), supported by a tridentate ligand (L = 1-(2-phenethyl)-5-[2-(2-pyridyl)ethyl]-1,5-diazacyclooctane) have been examined as a model compound of the putative reactive intermediate of peptidylglycine α-hydroxylating monooxygenase (PHM) and dopamine β-monooxygenase (DβM) (Kunishita et al. J. Am. Chem. Soc. 2009, 131, 2788-2789; Inorg. Chem. 2012, 51, 9465-9480). On the basis of the reactivity toward a series of one-electron reductants, the reduction potential of (L)Cu(II)-OO(•) was estimated to be 0.19 ± 0.07 V vs SCE in acetone at 298 K (cf. Tahsini et al. Chem.-Eur. J. 2012, 18, 1084-1093). In the reaction of TEMPO-H (2,2,6,6-tetramethylpiperidine-N-hydroxide), a simple HAT (hydrogen atom transfer) reaction took place to give the corresponding hydroperoxide complex LCu(II)-OOH, whereas the reaction with phenol derivatives ((X)ArOH) gave the corresponding phenolate adducts, LCu(II)-O(X)Ar, presumably via an acid-base reaction between the superoxide ligand and the phenols. The reaction of (L)Cu(II)-OO(•) with a series of triphenylphosphine derivatives gave the corresponding triphenylphosphine oxides via an electrophilic ionic substitution mechanism with a Hammett ρ value as -4.3, whereas the reaction with thioanisole (sulfide) only gave a copper(I) complex. These reactivities of (L)Cu(II)-OO(•) are different from those of a similar end-on superoxide copper(II) complex supported by a tetradentate TMG3tren ligand (1,1,1-Tris{2-[N(2)-(1,1,3,3-tetramethylguanidino)]ethyl}amine (Maiti et al. Angew. Chem., Int. Ed. 2008, 47, 82-85).

  4. Autoxidation of ubiquinol-6 is independent of superoxide dismutase.

    PubMed

    Schultz, J R; Ellerby, L M; Gralla, E B; Valentine, J S; Clarke, C F

    1996-05-28

    Ubiquinone (Q) is an essential, lipid soluble, redox component of the mitochondrial respiratory chain. Much evidence suggests that ubiquinol (QH2) functions as an effective antioxidant in a number of membrane and biological systems by preventing peroxidative damage to lipids. It has been proposed that superoxide dismutase (SOD) may protect QH2 form autoxidation by acting either directly as a superoxide-semiquinone oxidoreductase or indirectly by scavenging superoxide. In this study, such an interaction between QH2 and SOD was tested by monitoring the fluorescence of cis-parinaric acid (cPN) incorporated phosphatidylcholine (PC) liposomes. Q6H2 was found to prevent both fluorescence decay and generation of lipid peroxides (LOOH) when peroxidation was initiated by the lipid-soluble azo initiator DAMP, dimethyl 2,2'-azobis (2-methylpropionate), while Q6 or SOD alone had no inhibitory effect. Addition of either SOD or catalase to Q6H2-containing liposomes had little effect on the rate of peroxidation even when incubated in 100% O2. Hence, the autoxidation of QH2 is a competing reaction that reduces the effectiveness of QH2 as an antioxidant and was not slowed by either SOD or catalase. The in vivo interaction of SOD and QH2 was also tested by employing yeast mutant strains harboring deletions in either CuZnSOD and/or MnSOD. The sod mutant yeast strains contained the same percent Q6H2 per cell as wild-type cells. These results indicate that the autoxidation of QH2 is independent of SOD. PMID:8639607

  5. 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.

  6. Theoretical determination of the alkali-metal superoxide bond energies

    NASA Technical Reports Server (NTRS)

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

    1992-01-01

    The bond dissociation energies for the alkali-metal superoxides have been computed using extensive Gaussian basis sets and treating electron correlation at the modified coupled-pair functional level. Our computed D0 values are 61.4, 37.2, 40.6, and 38.4 kcal/mol for LiO2, NaO2, KO2, and RbO2, respectively. These values, which are expected to be lower bounds and accurate to 2 kcal/mol, agree well with some of the older flame data, but rule out several recent experimental measurements.

  7. 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

  8. Biologically active metal-independent superoxide dismutase mimics

    SciTech Connect

    Mitchell, J.B.; Samuni, A.; Krishna, M.C.; DeGraff, W.G.; Ahn, M.S.; Samuni, U.; Russo, A. )

    1990-03-20

    Superoxide dismutase (SOD) is an enzyme that detoxifies superoxide (O2.-), a potentially toxic oxygen-derived species. Attempts to increase intracellular concentrations of SOD by direct application are complicated because SOD, being a relatively large molecule, does not readily cross cell membranes. We have identified a set of stable nitroxides that possess SOD-like activity, have the advantage of being low molecular weight, membrane permeable, and metal independent, and at pH 7.0 have reaction rate constants with O2.- ranging from 1.1 x 10(3) to 1.3 x 10(6) M-1 s-1. These SOD mimics protect mammalian cells from damage induced by hypoxanthine/xanthine oxidase and H{sub 2}O{sub 2}, although they exhibit no catalase-like activity. In addition, the nitroxide SOD mimics rapidly oxidize DNA-FeII and thus may interrupt the Fenton reaction and prevent formation of deleterious OH radicals and/or higher oxidation states of metal ions. Whether by SOD-like activity and/or interception of an electron from redox-active metal ions they protect cells from oxidative stress and may have use in basic and applied biological studies.

  9. Metabolic alterations in yeast lacking copper-zinc superoxide dismutase.

    PubMed

    Sehati, Sadaf; Clement, Matthew H S; Martins, Jake; Xu, Lei; Longo, Valter D; Valentine, Joan S; Gralla, Edith B

    2011-06-01

    Yeast lacking copper-zinc superoxide dismutase (sod1∆) have a number of oxygen-dependent defects, including auxotrophies for lysine and methionine and sensitivity to oxygen. Here we report additional defects in metabolic regulation. Under standard growth conditions with glucose as the carbon source, yeast undergo glucose repression in which mitochondrial respiration is deemphasized, energy is mainly derived from glycolysis, and ethanol is produced. When glucose is depleted, the diauxic shift is activated, in which mitochondrial respiration is reemphasized and stress resistance increases. We find that both of these programs are adversely affected by the lack of Sod1p. Key events in the diauxic shift do not occur and sod1∆ cells do not utilize ethanol and stop growing. The ability to shift to growth on ethanol is gradually lost as time in culture increases. In early stages of culture, sod1∆ cells consume more oxygen and have more mitochondrial mass than wild-type cells, indicating that glucose repression is not fully activated. These changes are at least partially dependent on the activity of the Hap2,3,4,5 complex, as indicated by CYC1-lacZ reporter assays. These changes may indicate a role for superoxide in metabolic signaling and regulation and/or a role for glucose derepression in defense against oxidative stress.

  10. Superoxide overproduction and kidney fibrosis: a new animal model

    PubMed Central

    Guimarães-Souza, Nadia Karina; Yamaleyeva, Liliya Marsovna; Lu, Baisong; Ramos, Ana Claudia Mallet de Souza; Bishop, Colin Edward; Andersson, Karl Erik

    2015-01-01

    Objective To establish whether the mutation in the Immp2L gene induces renal fibrosis and whether aging exacerbates renal morphology in mice. Methods Female mutant mice with mutation in the inner mitochondrial membrane peptidase 2-like protein at 3 and 18 months of age were used. Renal fibrosis was analyzed using classic fibrosis score, Masson’s trichrome staining, and analysis of profibrotic markers using real time polymerase chain reaction (superoxide dismutase 1, metalloproteinase-9, erythropoietin, transforming growth factor beta), and immunostaining (fibroblasts and Type IV collagen). Oxidative stress markers were determined by immunohistochemistry. The number of renal apoptotic cells was determined. Renal function was estimated by serum creatinine. Results Young mutant mice had significantly more glomerulosclerosis than age-matched mice (p=0.034). Mutant mice had more tubular casts (p=0.025), collagen deposition (p=0.019), and collagen type IV expression (p<0.001). Superoxide dismutase 1 expression was significantly higher in young mutants (p=0.038). Old mutants exhibited significantly higher expression of the fibroblast marker and macrophage marker (p=0.007 and p=0.012, respectively). The real time polymerase chain reaction of metalloproteinase-9 and erythropoietin were enhanced 2.5- and 6-fold, respectively, in old mutants. Serum creatinine was significantly higher in old mutants (p<0.001). Conclusion This mutation altered renal architecture by increasing the deposition of extracellular matrix, oxidative stress, and inflammation, suggesting a protective role of Immp2L against renal fibrosis. PMID:25993073

  11. Molecular characterization of two superoxide dismutases from Hydra vulgaris

    PubMed Central

    Dash, Bhagirathi; Metz, Richard; Huebner, Henry J.; Porter, Weston; Phillips, Timothy D.

    2007-01-01

    Apparent full-length cDNA sequences coding for manganese superoxide dismutase (HvMnSOD) and extracellular superoxide dismutase (HvEC-SOD) were isolated from Hydra vulgaris in order to understand their expression and 3D structures; and explore their possibility of being used as for biomarkers for environmental stress and toxicity. The deduced HvMnSOD protein consists of 219 amino acids of which first 21 amino acids constitute a presumed mitochondria-targeting signal peptide whereas HvEC-SOD protein consists of 189 amino acids of which first 19 amino acids constitute a presumed signal peptide. Molecular model generated for HvMnSOD displayed the N-terminal long alpha antiparallel hairpin and the C-terminal mixed alpha/beta fold characteristic of MnSODs and that for HvEC-SOD displayed the characteristic CuZnSOD beta-barrel fold. Hydrae subjected to thermal, starvation, metal and oxidative stress responded by regulating MnSOD and EC-SOD mRNA transcription. These results indicated that these genes are involved in the cellular stress response and (anti)oxidative processes triggered by stressor and contaminant exposure. Hence the expression of these SODs in hydra may have potential as molecular biomarkers for assessing stress, toxicity and pro-oxidant quality of chemicals and aquatic environmental quality. PMID:17150313

  12. Acute hypoxia produces a superoxide burst in cells.

    PubMed

    Hernansanz-Agustín, Pablo; Izquierdo-Álvarez, Alicia; Sánchez-Gómez, Francisco J; Ramos, Elena; Villa-Piña, Tamara; Lamas, Santiago; Bogdanova, Anna; Martínez-Ruiz, Antonio

    2014-06-01

    Oxygen is a key molecule for cell metabolism. Eukaryotic cells sense the reduction in oxygen availability (hypoxia) and trigger a series of cellular and systemic responses to adapt to hypoxia, including the optimization of oxygen consumption. Many of these responses are mediated by a genetic program induced by the hypoxia-inducible transcription factors (HIFs), regulated by a family of prolyl hydroxylases (PHD or EGLN) that use oxygen as a substrate producing HIF hydroxylation. In parallel to these oxygen sensors modulating gene expression within hours, acute modulation of protein function in response to hypoxia is known to occur within minutes. Free radicals acting as second messengers, and oxidative posttranslational modifications, have been implied in both groups of responses. Localization and speciation of the paradoxical increase in reactive oxygen species production in hypoxia remain debatable. We have observed that several cell types respond to acute hypoxia with a transient increase in superoxide production for about 10 min, probably originating in the mitochondria. This may explain in part the apparently divergent results found by various groups that have not taken into account the time frame of hypoxic ROS production. We propose that this acute and transient hypoxia-induced superoxide burst may be translated into oxidative signals contributing to hypoxic adaptation and preconditioning.

  13. Mechanism of Action of Sulforaphane as a Superoxide Radical Anion and Hydrogen Peroxide Scavenger by Double Hydrogen Transfer: A Model for Iron Superoxide Dismutase.

    PubMed

    Prasad, Ajit Kumar; Mishra, P C

    2015-06-25

    The mechanism of action of sulforaphane as a scavenger of superoxide radical anion (O2(•-)) and hydrogen peroxide (H2O2) was investigated using density functional theory (DFT) in both gas phase and aqueous media. Iron superoxide dismutase (Fe-SOD) involved in scavenging superoxide radical anion from biological media was modeled by a complex consisting of the ferric ion (Fe(3+)) attached to three histidine rings. Reactions related to scavenging of superoxide radical anion by sulforaphane were studied using DFT in the presence and absence of Fe-SOD represented by this model in both gas phase and aqueous media. The scavenging action of sulforaphane toward both superoxide radical anion and hydrogen peroxide was found to involve the unusual mechanism of double hydrogen transfer. It was found that sulforaphane alone, without Fe-SOD, cannot scavenge superoxide radical anion in gas phase or aqueous media efficiently as the corresponding reaction barriers are very high. However, in the presence of Fe-SOD represented by the above-mentioned model, the scavenging reactions become barrierless, and so sulforaphane scavenges superoxide radical anion by converting it to hydrogen peroxide efficiently. Further, sulforaphane was found to scavenge hydrogen peroxide also very efficiently by converting it into water. Thus, the mechanism of action of sulforaphane as an excellent antioxidant has been unravelled. PMID:26020652

  14. Mechanism of Action of Sulforaphane as a Superoxide Radical Anion and Hydrogen Peroxide Scavenger by Double Hydrogen Transfer: A Model for Iron Superoxide Dismutase.

    PubMed

    Prasad, Ajit Kumar; Mishra, P C

    2015-06-25

    The mechanism of action of sulforaphane as a scavenger of superoxide radical anion (O2(•-)) and hydrogen peroxide (H2O2) was investigated using density functional theory (DFT) in both gas phase and aqueous media. Iron superoxide dismutase (Fe-SOD) involved in scavenging superoxide radical anion from biological media was modeled by a complex consisting of the ferric ion (Fe(3+)) attached to three histidine rings. Reactions related to scavenging of superoxide radical anion by sulforaphane were studied using DFT in the presence and absence of Fe-SOD represented by this model in both gas phase and aqueous media. The scavenging action of sulforaphane toward both superoxide radical anion and hydrogen peroxide was found to involve the unusual mechanism of double hydrogen transfer. It was found that sulforaphane alone, without Fe-SOD, cannot scavenge superoxide radical anion in gas phase or aqueous media efficiently as the corresponding reaction barriers are very high. However, in the presence of Fe-SOD represented by the above-mentioned model, the scavenging reactions become barrierless, and so sulforaphane scavenges superoxide radical anion by converting it to hydrogen peroxide efficiently. Further, sulforaphane was found to scavenge hydrogen peroxide also very efficiently by converting it into water. Thus, the mechanism of action of sulforaphane as an excellent antioxidant has been unravelled.

  15. Superoxide Mediates the Toxicity of Paraquat for Chinese Hamster Ovary Cells

    NASA Astrophysics Data System (ADS)

    Bagley, Ann C.; Krall, Judith; Lynch, Robert E.

    1986-05-01

    The roles of superoxide and H2O2 in the cytotoxicity of paraquat were assessed in Chinese hamster ovary cells. Neither catalase nor superoxide dismutase inhibited the loss of ability to form colonies when added to the medium. When introduced into the cells, superoxide dismutase but not catalase inhibited the toxicity of paraquat. That superoxide dismutase acted by its known catalytic action is shown by the loss of inhibition when the enzyme was inactivated by H2O2 before being introduced into the cells. The lack of inhibition by catalase, by dimethyl sulfoxide, and by desferoxamine suggests that the toxicity is not mediated by a reaction between H2O2 and superoxide to engender the hydroxyl radical. Exposure of Chinese hamster ovary cells to paraquat may be a suitable means to determine the effects of superoxide anion in cultured cells and the ways in which cells can resist this toxic action.

  16. Superoxide dismutase activity in needles of Norwegian spruce trees (Picea abies L. )

    SciTech Connect

    Polle, A.; Krings, B.; Rennenberg, H. Universitaet zu Koeln )

    1989-08-01

    The activity of superoxide dismutase was investigated in needles of spruce trees. To obtain maximum activity, needles were homogenized in the presence of Triton X-100 and polyvinylpyrrolidone. Superoxide dismutase activity was measured in dialyzed extracts with a modified epinephrine assay at pH 10.2. The extracts contained 70 to 120 units of superoxide dismutase per milligram protein. One unit of superoxide dismutase was completely inhibited in the presence of 20 micromolar NaCN. On native polyacrylamide gels three electromorphs were visualized after staining for activity. All three species were sensitive to CN{sup {minus}} and H{sub 2}O{sub 2} and were therefore assumed to be Cu/Zn-superoxide dismutases. Superoxide dismutase activity was dependent on the age of the needles and declined by approximately 25% within 3 to 4 years.

  17. Some dinophycean red tide plankton species generate a superoxide scavenging substance.

    PubMed

    Sato, Emiko; Niwano, Yoshimi; Matsuyama, Yukihiko; Kim, Daekyung; Nakashima, Takuji; Oda, Tatsuya; Kohno, Masahiro

    2007-03-01

    Recent studies indicate that some raphidophycean red tide flagellates produce substances able to scavenge superoxide, whereas there have been no reports on superoxide scavenger production by dinophycean red tide flagellates. In this study, we examined the superoxide-scavenging activity of aqueous extracts from dinophycean red tide flagellates, Gymnodinium spp., Scrippsiella trochoidea, and Karenia sp., by a luminol analog L-012-dependent chemiluminescence (CL) method and an electron spin resonance (ESR)-spin trapping method, and compared the activity to that of raphidophycean red tide flagellates, Chattonella spp., Heterosigma akashiwo, and Fibrocapsa japonica. In the experiment applying the L-012-dependent CL method, only the aqueous extracts from raphidophycean red tide flagellates showed superoxide-scavenging activity. On the other hand, applying the ESR-spin trapping method, we found that the aqueous extracts from dinophycean red tide flagellates also showed superoxide-scavenging activity. This is the first report on the production of a superoxide-scavenger by dinophycean red tide flagellates.

  18. Comparative analysis of cyanobacterial superoxide dismutases to discriminate canonical forms

    PubMed Central

    Priya, Balakrishnan; Premanandh, Jagadeesan; Dhanalakshmi, Raman T; Seethalakshmi, Thangaraj; Uma, Lakshmanan; Prabaharan, Dharmar; Subramanian, Gopalakrishnan

    2007-01-01

    Background Superoxide dismutases (SOD) are ubiquitous metalloenzymes that catalyze the disproportion of superoxide to peroxide and molecular oxygen through alternate oxidation and reduction of their metal ions. In general, SODs are classified into four forms by their catalytic metals namely; FeSOD, MnSOD, Cu/ZnSOD and NiSOD. In addition, a cambialistic form that uses Fe/Mn in its active site also exists. Cyanobacteria, the oxygen evolving photosynthetic prokaryotes, produce reactive oxygen species that can damage cellular components leading to cell death. Thus, the co-evolution of an antioxidant system was necessary for the survival of photosynthetic organisms with SOD as the initial enzyme evolved to alleviate the toxic effect. Cyanobacteria represent the first oxygenic photoautotrophs and their SOD sequences available in the databases lack clear annotation. Hence, the present study focuses on structure and sequence pattern of subsets of cyanobacterial superoxide dismutases. Result The sequence conservation and structural analysis of Fe (Thermosynechococcus elongatus BP1) and MnSOD (Anabaena sp. PCC7120) reveal the sharing of N and C terminal domains. At the C terminal domain, the metal binding motif in cyanoprokaryotes is DVWEHAYY while it is D-X-[WF]-E-H-[STA]-[FY]-[FY] in other pro- and eukaryotes. The cyanobacterial FeSOD differs from MnSOD at least in three ways viz. (i) FeSOD has a metal specific signature F184X3A188Q189.......T280......F/Y303 while, in Mn it is R184X3G188G189......G280......W303, (ii) aspartate ligand forms a hydrogen bond from the active site with the outer sphere residue of W243 in Fe where as it is Q262 in MnSOD; and (iii) two unique lysine residues at positions 201 and 255 with a photosynthetic role, found only in FeSOD. Further, most of the cyanobacterial Mn metalloforms have a specific transmembrane hydrophobic pocket that distinguishes FeSOD from Mn isoform. Cyanobacterial Cu/ZnSOD has a copper domain and two different signatures G

  19. Basal superoxide as a sex-specific immune constraint.

    PubMed

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

    2011-12-23

    There is increasing evidence that reactive oxygen species (ROS), a group of unstable and highly reactive chemical molecules, play a key role in regulating and maintaining life-history trade-offs. Upregulation of ROS in association with immune activation is costly because it may result in an imbalance between pro- and antioxidants and, hence, oxidative damage. Previous research aimed at quantifying this cost has mostly focused on changes in the pro-/antioxidant balance subsequent to an immune response. Here, we test the hypothesis that systemic ROS may constrain immune activation. We show that systemic, pre-challenge superoxide (SO) levels are negatively related to the strength of the subsequent immune response towards the mitogen phytohaemagglutinin in male, but not female painted dragon lizards (Ctenophorus pictus). We therefore suggest that systemic SO constrains immune activation in painted dragon males. We speculate that this may be due to sex-specific selection pressures on immune investment. PMID:21632618

  20. Superoxide Dismutase and Catalase Genotypes in Pediatric Migraine Patients.

    PubMed

    Saygi, Semra; Erol, İlknur; Alehan, Füsun; Yalçın, Yaprak Yılmaz; Kubat, Gözde; Ataç, Fatma Belgin

    2015-10-01

    This study compared superoxide dismutase (SOD) and catalase (CAT) alleles in 97 consecutive children and adolescents with migraine to 96 healthy children and adolescents. Isolated genomic DNA was used as a template for SOD1 (35 A/C), SOD2 16 C/T, and CAT2 [(-262 C/T) and (-21 A/T)] allele genotyping. The SOD2 16 C/T genotype and C allele frequency differed significantly between controls and migraine (P = .047; P = .038). CAT -21 AA genotype and A allele frequency were significantly higher in both migraine with aura patients (P = .013; P = .004) and migraine without aura patients (P = .003; P = .001) compared to controls. To our knowledge, this is the first demonstration of differences in SOD and CAT genotypes between pediatric migraine patients and age-matched controls. Further studies on the functional implications of these genetic variants on neural antioxidant capacity and the use of antioxidant modulators for migraine treatment are warranted.

  1. The signaling role of a mitochondrial superoxide burst during stress.

    PubMed

    Cvetkovska, Marina; Alber, Nicole A; Vanlerberghe, Greg C

    2013-01-01

    Plant mitochondria are proposed to act as signaling organelles in the orchestration of defense responses to biotic stress and acclimation responses to abiotic stress. However, the primary signal(s) being generated by mitochondria and then interpreted by the cell are largely unknown. Recently, we showed that mitochondria generate a sustained burst of superoxide (O 2(-)) during particular plant-pathogen interactions. This O 2(-) burst appears to be controlled by mitochondrial components that influence rates of O 2(-) generation and scavenging within the organelle. The O 2(-) burst appears to influence downstream processes such as the hypersensitive response, indicating that it could represent an important mitochondrial signal in support of plant stress responses. The findings generate many interesting questions regarding the upstream factors required to generate the O 2(-) burst, the mitochondrial events that occur in support of and in parallel with this burst and the downstream events that respond to this burst.

  2. Metalloantibiotic Mn(II)-bacitracin complex mimicking manganese superoxide dismutase

    SciTech Connect

    Piacham, Theeraphon; Isarankura-Na-Ayudhya, Chartchalerm; Nantasenamat, Chanin; Yainoy, Sakda; Ye Lei; Buelow, Leif; Prachayasittikul, Virapong . E-mail: mtvpr@mucc.mahidol.ac.th

    2006-03-24

    Superoxide dismutase (SOD) activities of various metallobacitracin complexes were evaluated using the riboflavin-methionine-nitro blue tetrazolium assay. The radical scavenging activity of various metallobacitracin complexes was shown to be higher than those of the negative controls, e.g., free transition metal ions and metal-free bacitracin. The SOD activity of the complex was found to be in the order of Mn(II) > Cu(II) > Co(II) > Ni(II). Furthermore, the effect of bacitracin and their complexation to metals on various microorganisms was assessed by antibiotic susceptibility testing. Moreover, molecular modeling and quantum chemical calculation of the metallobacitracin complex was performed to evaluate the correlation of electrostatic charge of transition metal ions on the SOD activity.

  3. Superoxide dismutase amplifies organismal sensitivity to ionizing radiation

    SciTech Connect

    Scott, M.D.; Meshnick, S.R.; Eaton, J.W.

    1989-02-15

    Although increased superoxide dismutase (SOD) activity is often associated with enhanced resistance of cells and organisms to oxidant challenges, few direct tests of the antioxidant importance of this enzyme have been carried out. To assess the importance of SOD in defending against gamma-radiation, we employed Escherichia coli with deficient, normal, and super-normal enzyme activities. Surprisingly, the radiation sensitivity of E. coli actually increases as bacterial SOD activity increases. Elevated intracellular SOD activity sensitizes E. coli to radiation-induced mortality, whereas SOD-deficient bacteria show normal or decreased radiosensitivity. Toxic effects of activated oxygen species are involved in this phenomenon; bacterial SOD activity has no effect on radiation sensitivity under anaerobic conditions or on the lethality of other, non-oxygen-dependent, toxins such as ultraviolet radiation.

  4. Methylglyoxal as a scavenger for superoxide anion-radical.

    PubMed

    Shumaev, K B; Lankin, V Z; Konovalova, G G; Grechnikova, M A; Tikhaze, A K

    2016-07-01

    Methylglyoxal at a concentration of 5 mM caused a significant inhibition of superoxide anion radical (O2 (·-)) comparable to the effect of Tirone. In the process of O2 (·-) generation in the system of egg phosphatidylcholine liposome peroxidation induced by the azo-initiator AIBN, a marked inhibition of chemiluminescence in the presence of 100 mM methylglyoxal was found. At the same time, methylglyoxal did not inhibit free radical peroxidation of low-density lipoprotein particles, which indicates the absence of interaction with methylglyoxal alkoxyl and peroxyl polyenoic lipid radicals. These findings deepen information about the role of methylglyoxal in the regulation of free radical processes. PMID:27599518

  5. Basal superoxide as a sex-specific immune constraint

    PubMed Central

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

    2011-01-01

    There is increasing evidence that reactive oxygen species (ROS), a group of unstable and highly reactive chemical molecules, play a key role in regulating and maintaining life-history trade-offs. Upregulation of ROS in association with immune activation is costly because it may result in an imbalance between pro- and antioxidants and, hence, oxidative damage. Previous research aimed at quantifying this cost has mostly focused on changes in the pro-/antioxidant balance subsequent to an immune response. Here, we test the hypothesis that systemic ROS may constrain immune activation. We show that systemic, pre-challenge superoxide (SO) levels are negatively related to the strength of the subsequent immune response towards the mitogen phytohaemagglutinin in male, but not female painted dragon lizards (Ctenophorus pictus). We therefore suggest that systemic SO constrains immune activation in painted dragon males. We speculate that this may be due to sex-specific selection pressures on immune investment. PMID:21632618

  6. Stability of ALS-related Superoxide Dismutase Protein variants

    NASA Astrophysics Data System (ADS)

    Lusebrink, Daniel; Plotkin, Steven

    Superoxide dismutase (SOD1) is a metal binding, homodimeric protein, whose misfolding is implicated in the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Monomerization is believed to be a key step in the propagation of the disease. The dimer stability is often difficult to measure experimentally however, because it is entangled with protein unfolding and metal loss. We thus computationally investigate the dimer stability of mutants of SOD1 known to be associated with ALS. We report on systematic trends in dimer stability, as well as intriguing allosteric communication between mutations and the dimer interface. We study the dimer stabilities in molecular dynamics simulations and obtain the binding free energies of the dimers from pulling essays. Mutations are applied in silicoand we compare the differences of binding free energies compared to the wild type.

  7. Permeability Transition Pore-Mediated Mitochondrial Superoxide Flashes Regulate Cortical Neural Progenitor Differentiation

    PubMed Central

    Hou, Yan; Mattson, Mark P.; Cheng, Aiwu

    2013-01-01

    In the process of neurogenesis, neural progenitor cells (NPCs) cease dividing and differentiate into postmitotic neurons that grow dendrites and an axon, become excitable, and establish synapses with other neurons. Mitochondrial biogenesis and aerobic metabolism provide energy substrates required to support the differentiation, growth and synaptic activity of neurons. Mitochondria may also serve signaling functions and, in this regard, it was recently reported that mitochondria can generate rapid bursts of superoxide (superoxide flashes), the frequency of which changes in response to environmental conditions and signals including oxygen levels and Ca2+ fluxes. Here we show that the frequency of mitochondrial superoxide flashes increases as embryonic cerebral cortical neurons differentiate from NPCs, and provide evidence that the superoxide flashes serve a signaling function that is critical for the differentiation process. The superoxide flashes are mediated by mitochondrial permeability transition pore (mPTP) opening, and pharmacological inhibition of the mPTP suppresses neuronal differentiation. Moreover, superoxide flashes and neuronal differentiation are inhibited by scavenging of mitochondrial superoxide. Conversely, manipulations that increase superoxide flash frequency accelerate neuronal differentiation. Our findings reveal a regulatory role for mitochondrial superoxide flashes, mediated by mPTP opening, in neuronal differentiation. PMID:24116142

  8. Superoxide-mediated activation of uncoupling protein 2 causes pancreatic β cell dysfunction

    PubMed Central

    Krauss, Stefan; Zhang, Chen-Yu; Scorrano, Luca; Dalgaard, Louise T.; St-Pierre, Julie; Grey, Shane T.; Lowell, Bradford B.

    2003-01-01

    Failure to secrete adequate amounts of insulin in response to increasing concentrations of glucose is an important feature of type 2 diabetes. The mechanism for loss of glucose responsiveness is unknown. Uncoupling protein 2 (UCP2), by virtue of its mitochondrial proton leak activity and consequent negative effect on ATP production, impairs glucose-stimulated insulin secretion. Of interest, it has recently been shown that superoxide, when added to isolated mitochondria, activates UCP2-mediated proton leak. Since obesity and chronic hyperglycemia increase mitochondrial superoxide production, as well as UCP2 expression in pancreatic β cells, a superoxide-UCP2 pathway could contribute importantly to obesity- and hyperglycemia-induced β cell dysfunction. This study demonstrates that endogenously produced mitochondrial superoxide activates UCP2-mediated proton leak, thus lowering ATP levels and impairing glucose-stimulated insulin secretion. Furthermore, hyperglycemia- and obesity-induced loss of glucose responsiveness is prevented by reduction of mitochondrial superoxide production or gene knockout of UCP2. Importantly, reduction of superoxide has no beneficial effect in the absence of UCP2, and superoxide levels are increased further in the absence of UCP2, demonstrating that the adverse effects of superoxide on β cell glucose sensing are caused by activation of UCP2. Therefore, superoxide-mediated activation of UCP2 could play an important role in the pathogenesis of β cell dysfunction and type 2 diabetes. PMID:14679178

  9. Selective superoxide generation within mitochondria by the targeted redox cycler MitoParaquat.

    PubMed

    Robb, Ellen L; Gawel, Justyna M; Aksentijević, Dunja; Cochemé, Helena M; Stewart, Tessa S; Shchepinova, Maria M; Qiang, He; Prime, Tracy A; Bright, Thomas P; James, Andrew M; Shattock, Michael J; Senn, Hans M; Hartley, Richard C; Murphy, Michael P

    2015-12-01

    Superoxide is the proximal reactive oxygen species (ROS) produced by the mitochondrial respiratory chain and plays a major role in pathological oxidative stress and redox signaling. While there are tools to detect or decrease mitochondrial superoxide, none can rapidly and specifically increase superoxide production within the mitochondrial matrix. This lack impedes progress, making it challenging to assess accurately the roles of mitochondrial superoxide in cells and in vivo. To address this unmet need, we synthesized and characterized a mitochondria-targeted redox cycler, MitoParaquat (MitoPQ) that comprises a triphenylphosphonium lipophilic cation conjugated to the redox cycler paraquat. MitoPQ accumulates selectively in the mitochondrial matrix driven by the membrane potential. Within the matrix, MitoPQ produces superoxide by redox cycling at the flavin site of complex I, selectively increasing superoxide production within mitochondria. MitoPQ increased mitochondrial superoxide in isolated mitochondria and cells in culture ~a thousand-fold more effectively than untargeted paraquat. MitoPQ was also more toxic than paraquat in the isolated perfused heart and in Drosophila in vivo. MitoPQ enables the selective generation of superoxide within mitochondria and is a useful tool to investigate the many roles of mitochondrial superoxide in pathology and redox signaling in cells and in vivo.

  10. [Antifibrosis effect of modified forms of catalase and superoxide dismutase in experimental silicosis].

    PubMed

    Maksimenko, A V; Bezrukavnikova, L M; Grigor'eva, E L; Tishchenko, E G; Arkhipova, O G; Iaglov, V V; Torchilin, V P

    1992-01-01

    The forms of catalase modified by treatment with dextran aldehyde were obtained and studied. Efficacy of the preparations containing native and modified forms of catalase and superoxide dismutase as well as their covalent bienzyme conjugate containing catalase-dextran aldehyde-superoxide dismutase was studied in rats with simulated silicosis. The preparations were administered into rats by means of inhalation and intraperitoneal injection. Positive protective effect exhibited a mixture of native enzymes and their covalent conjugate. The most pronounced additional effect was caused by the mixture of native catalase and superoxide dismutase as compared with modified preparation of superoxide dismutase. The preparation of bienzyme containing conjugate was less effective. PMID:1384235

  11. Superoxide Induces Neutrophil Extracellular Trap Formation in a TLR-4 and NOX-Dependent Mechanism

    PubMed Central

    Al-Khafaji, Ahmed B; Tohme, Samer; Yazdani, Hamza Obaid; Miller, David; Huang, Hai; Tsung, Allan

    2016-01-01

    Neutrophils constitute the early innate immune response to perceived infectious and sterile threats. Neutrophil extracellular traps (NETs) are a novel mechanism to counter pathogenic invasion and sequelae of ischemia, including cell death and oxidative stress. Superoxide is a radical intermediate of oxygen metabolism produced by parenchymal and nonparenchymal hepatic cells, and is a hallmark of oxidative stress after liver ischemia-reperfusion (I/R). While extracellular superoxide recruits neutrophils to the liver and initiates sterile inflammatory injury, it is unknown whether superoxide induces the formation of NETs. We hypothesize that superoxide induces NET formation through a signaling cascade involving Toll-like receptor 4 (TLR-4) and neutrophil NADPH oxidase (NOX). We treated neutrophils with extracellular superoxide and observed NET DNA release, histone H3 citrullination and increased levels of MPO-DNA complexes occurring in a TLR-4–dependent manner. Inhibition of superoxide generation by allopurinol and inhibition of NOX by diphenyleneiodonium prevented NET formation. When mice were subjected to warm liver I/R, we found significant NET formation associated with liver necrosis and increased serum ALT in TLR-4 WT but not TLR-4 KO mice. To reduce circulating superoxide, we pretreated mice undergoing I/R with allopurinol and N-acetylcysteine, which resulted in decreased NETs and ameliorated liver injury. Our study demonstrates a requirement for TLR-4 and NOX in superoxide-induced NETs, and suggests involvement of superoxide-induced NETs in pathophysiologic settings. PMID:27453505

  12. Theoretical study of the correlation between superoxide anion consumption and firefly luciferin chemiluminescence

    NASA Astrophysics Data System (ADS)

    Pinto da Silva, Luís; Esteves da Silva, Joaquim C. G.

    2013-07-01

    This is the first theoretical study of the relationship between superoxide anion and firefly chemiluminescence, in DMSO. Electron transfer reactions between luciferin dianionic/carbanionic/radical species and superoxide were studied in order see if an alternative explanation existed for the consumption of the latter species, without correlating it with a role on luciferin chemiluminescence. Despite the finding that luciferin may indeed inhibit the formation of the superoxide anion, no theoretical evidence was found that showed that this molecule is consumed in a non-chemiluminescence reaction. Therefore, it is concluded that the superoxide anion is indeed related to the firefly luciferin chemiluminescence.

  13. Effects of oxidative stress on expression of extracellular superoxide dismutase, CuZn-superoxide dismutase and Mn-superoxide dismutase in human dermal fibroblasts.

    PubMed

    Strålin, P; Marklund, S L

    1994-03-01

    To determine the effect of oxidative stress on expression of extracellular superoxide dismutase (EC-SOD), CuZn-SOD and Mn-SOD, two fibroblast lines were exposed for periods of up to 4 days to a wide concentration range of oxidizing agents: xanthine oxidase plus hypoxanthine, paraquat, pyrogallol, alpha-naphthoflavone, hydroquinone, catechol, Fe2+ ions, Cu2+ ions, buthionine sulphoximine, diethylmaleate, t-butyl hydroperoxide, cumene hydroperoxide, selenite, citiolone and high oxygen partial pressure. The cell lines were cultured both under serum starvation and at a serum concentration that permitted growth. Under no condition was there any evidence of EC-SOD induction. Instead, the agents uniformly, dose-dependently and continuously reduced EC-SOD expression. We interpret the effect to be due to toxicity. Enhancement of the protection against oxidative stress by addition of CuZn-SOD, catalase and low concentrations of selenite did not influence the expression of any of the SOD isoenzymes. Removal of EC-SOD from cell surfaces by heparin also did not influence SOD expression. Mn-SOD was moderately induced by high doses of the first 11 oxidants. Apart from reduction at high toxic doses, there were no significant effects on the CuZn-SOD activity by any of the treatments. Thus EC-SOD, previously shown to be profoundly influenced by inflammatory cytokines, was not induced by its substrate or other oxidants. In a similar fashion, Mn-SOD, previously shown to be greatly induced and depressed by cytokines, was only moderately influenced by oxidants. We suggest that the regulation of these SOD isoenzymes in mammalian tissues primarily occurs in a manner co-ordinated by cytokines, rather than as a response of individual cells to oxidants. PMID:8135741

  14. 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...

  15. Superoxide reacts with nitric oxide to nitrate tyrosine at physiological pH via peroxynitrite.

    PubMed

    Reiter, C D; Teng, R J; Beckman, J S

    2000-10-20

    Tyrosine nitration is a widely used marker of peroxynitrite (ONOO(-)) produced from the reaction of nitric oxide with superoxide. Pfeiffer and Mayer (Pfeiffer, S., and Mayer, B. (1998) J. Biol. Chem. 273, 27280-27285) reported that superoxide produced from hypoxanthine plus xanthine oxidase in combination with nitric oxide produced from spermine NONOate did not nitrate tyrosine at neutral pH. They suggested that nitric oxide and superoxide at neutral pH form a less reactive intermediate distinct from preformed alkaline peroxynitrite that does not nitrate tyrosine. Using a stopped-flow spectrophotometer to rapidly mix potassium superoxide with nitric oxide at pH 7.4, we report that an intermediate spectrally and kinetically identical to preformed alkaline cis-peroxynitrite was formed in 100% yield. Furthermore, this intermediate nitrated tyrosine in the same yield and at the same rate as preformed peroxynitrite. Equivalent concentrations of nitric oxide under aerobic conditions in the absence of superoxide did not produce detectable concentrations of nitrotyrosine. Carbon dioxide increased the efficiency of nitration by nitric oxide plus superoxide to the same extent as peroxynitrite. In experiments using xanthine oxidase as a source of superoxide, tyrosine nitration was substantially inhibited by urate formed from hypoxanthine oxidation, which was sufficient to account for the lack of tyrosine nitration previously reported. We conclude that peroxynitrite formed from the reaction of nitric oxide with superoxide at physiological pH remains an important species responsible for tyrosine nitration in vivo. PMID:10906340

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  17. 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…

  18. 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 (+/+), ...

  19. Sensitive spectrophotometric method for the determination of superoxide dismutase activity in tissue extracts

    SciTech Connect

    Paoletti, F.; Aldinucci, D.; Mocali, A.; Caparrini, A.

    1986-05-01

    Superoxide dismutase (EC 1.15.1.1) has been assayed by a spectrophotometric method based on the inhibition of a superoxide-driven NADH oxidation. The assay consists of a purely chemical reaction sequence which involves EDTA. Mn(II), mercaptoethanol, and molecular oxygen, requiring neither auxiliary enzymes nor sophisticated equipment. The method is very flexible and rapid and is applicable with high sensitivity to the determination of both pure and crude superoxide dismutase preparations. The decrease of the rate of NADH oxidation is a function of enzyme concentration, and saturation levels are attainable. Fifty percent inhibition, corresponding to one unit of the enzyme, is produced by approximately 15 ng of pure superoxide dismutase. Experiments on rat liver cytosol have shown the specificity of the method for superoxide dismutase. Moreover, common cellular components do not interfere with the measurement, except for hemoglobin when present at relatively high concentrations. The assay is performed at physiological pH and is unaffected by catalase.

  20. 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. PMID:25053055

  1. Superoxide Dismutase 1 Nanozyme for Treatment of Eye Inflammation

    PubMed Central

    Kost, Olga A.; Beznos, Olga V.; Davydova, Nina G.; Manickam, Devika S.; Nikolskaya, Irina I.; Guller, Anna E.; Binevski, Petr V.; Chesnokova, Natalia B.; Shekhter, Anatoly B.; Klyachko, Natalia L.; Kabanov, Alexander V.

    2016-01-01

    Use of antioxidants to mitigate oxidative stress during ocular inflammatory diseases has shown therapeutic potential. This work examines a nanoscale therapeutic modality for the eye on the base of antioxidant enzyme, superoxide dismutase 1 (SOD1), termed “nanozyme.” The nanozyme is produced by electrostatic coupling of the SOD1 with a cationic block copolymer, poly(L-lysine)-poly(ethyleneglycol), followed by covalent cross-linking of the complexes with 3,3′-dithiobis(sulfosuccinimidylpropionate) sodium salt. The ability of SOD1 nanozyme as well as the native SOD1 to reduce inflammatory processes in the eye was examined in vivo in rabbits with immunogenic uveitis. Results suggested that topical instillations of both enzyme forms demonstrated anti-inflammatory activity; however, the nanozyme was much more effective compared to the free enzyme in decreasing uveitis manifestations. In particular, we noted statistically significant differences in such inflammatory signs in the eye as the intensities of corneal and iris edema, hyperemia of conjunctiva, lens opacity, fibrin clots, and the protein content in aqueous humor. Clinical findings were confirmed by histological data. Thus, SOD1-containing nanozyme is potentially useful therapeutic agent for the treatment of ocular inflammatory disorders. PMID:26697135

  2. Superoxide scavenging activity of pirfenidone-iron complex

    SciTech Connect

    Mitani, Yoshihiro; Sato, Keizo Muramoto, Yosuke; Karakawa, Tomohiro; Kitamado, Masataka; Iwanaga, Tatsuya; Nabeshima, Tetsuji; Maruyama, Kumiko; Nakagawa, Kazuko; Ishida, Kazuhiko; Sasamoto, Kazumi

    2008-07-18

    Pirfenidone (PFD) is focused on a new anti-fibrotic drug, which can minimize lung fibrosis etc. We evaluated the superoxide (O{sub 2}{sup {center_dot}}{sup -}) scavenging activities of PFD and the PFD-iron complex by electron spin resonance (ESR) spectroscopy, luminol-dependent chemiluminescence assay, and cytochrome c reduction assay. Firstly, we confirmed that the PFD-iron complex was formed by mixing iron chloride with threefold molar PFD, and the complex was stable in distillated water and ethanol. Secondary, the PFD-iron complex reduced the amount of O{sub 2}{sup {center_dot}}{sup -} produced by xanthine oxidase/hypoxanthine without inhibiting the enzyme activity. Thirdly, it also reduced the amount of O{sub 2}{sup {center_dot}}{sup -} released from phorbor ester-stimulated human neutrophils. PFD alone showed few such effects. These results suggest the possibility that the O{sub 2}{sup {center_dot}}{sup -} scavenging effect of the PFD-iron complex contributes to the anti-fibrotic action of PFD used for treating idiopathic pulmonary fibrosis.

  3. Biodegradable polycaprolactone (PCL) nanosphere encapsulating superoxide dismutase and catalase enzymes.

    PubMed

    Singh, Sushant; Singh, Abhay Narayan; Verma, Anil; Dubey, Vikash Kumar

    2013-12-01

    Biodegradable polycaprolactone (PCL) nanosphere encapsulating superoxide dismutase (SOD) and catalase (CAT) were successfully synthesized using double emulsion (w/o/w) solvent evaporation technique. Characterization of the nanosphere using dynamic light scattering, field emission scanning electron microscope, and Fourier transform infrared spectroscopy revealed a spherical-shaped nanosphere in a size range of 812 ± 64 nm with moderate protein encapsulation efficiency of 55.42 ± 3.7 % and high in vitro protein release. Human skin HaCat cells were used for analyzing antioxidative properties of SOD- and CAT-encapsulated PCL nanospheres. Oxidative stress condition in HaCat cells was optimized with exposure to hydrogen peroxide (H2O2; 1 mM) as external stress factor and verified through reactive oxygen species (ROS) analysis using H2DCFDA dye. PCL nanosphere encapsulating SOD and CAT together indicated better antioxidative defense against H2O2-induced oxidative stress in human skin HaCat cells in comparison to PCL encapsulating either SOD or CAT alone as well as against direct supplement of SOD and CAT protein solution. Increase in HaCat cells SOD and CAT activities after treatment hints toward uptake of PCL nanosphere into the human skin HaCat cells. The result signifies the role of PCL-encapsulating SOD and CAT nanosphere in alleviating oxidative stress.

  4. Status of Superoxide Dismutase in Transfusion Dependent Thalassaemia

    PubMed Central

    Rujito, Lantip; Mulatsih, Sri; Sofro, Abdul Salam M.

    2015-01-01

    Background: Thalassemia is a collection of genetic impairments in beta and alpha genes causing various states of anemia. Severe types of the disease need lifelong transfusions, leading to oxidant-antioxidant disturbance due to massive iron deposits. Aims: The aim of this study was to assess the antioxidant enzyme Superoxide Dismutase (SOD) and ferritin levels of thalassemia major patients in a peripheral health facility. Materials and Methods: Two hundred and nine probands were recruited and performed laboratory experiments for SOD and Ferritin levels. Chelation administration and clinical score were taken from interviewing the family and from medical report data. Results: The study showed that SOD intensity was lower (162.41 u/ml) compared to the normal cutoff point (P = 0.001), while the mean of Ferritin levels was ten times over the normal value (4226,67 ng/dl). Observations also reported that chelation medicine was not administrated properly. Conclusions: The data indicates that thalassemic patients have oxidant-antioxidant uproar due to oxidative stress. Monitored chelating administration, selective antioxidant, and a well-balanced diet may prevent oxidative injury. PMID:26110130

  5. NADPH Oxidase-Dependent Superoxide Production in Plant Reproductive Tissues.

    PubMed

    Jiménez-Quesada, María J; Traverso, José Á; Alché, Juan de Dios

    2016-01-01

    In the life cycle of a flowering plant, the male gametophyte (pollen grain) produced in the anther reaches the stigmatic surface and initiates the pollen-pistil interaction, an important step in plant reproduction, which ultimately leads to the delivery of two sperm cells to the female gametophyte (embryo sac) inside the ovule. The pollen tube undergoes a strictly apical expansion characterized by a high growth rate, whose targeting should be tightly regulated. A continuous exchange of signals therefore takes place between the haploid pollen and diploid tissue of the pistil until fertilization. In compatible interactions, theses processes result in double fertilization to form a zygote (2n) and the triploid endosperm. Among the large number of signaling mechanisms involved, the redox network appears to be particularly important. Respiratory burst oxidase homologs (Rbohs) are superoxide-producing enzymes involved in a broad range of processes in plant physiology. In this study, we review the latest findings on understanding Rboh activity in sexual plant reproduction, with a particular focus on the male gametophyte from the anther development stages to the crowning point of fertilization. Rboh isoforms have been identified in both the male and female gametophyte and have proven to be tightly regulated. Their role at crucial points such as proper growth of pollen tube, self-incompatibility response and eventual fertilization is discussed.

  6. NADPH Oxidase-Dependent Superoxide Production in Plant Reproductive Tissues

    PubMed Central

    Jiménez-Quesada, María J.; Traverso, José Á.; Alché, Juan de Dios

    2016-01-01

    In the life cycle of a flowering plant, the male gametophyte (pollen grain) produced in the anther reaches the stigmatic surface and initiates the pollen–pistil interaction, an important step in plant reproduction, which ultimately leads to the delivery of two sperm cells to the female gametophyte (embryo sac) inside the ovule. The pollen tube undergoes a strictly apical expansion characterized by a high growth rate, whose targeting should be tightly regulated. A continuous exchange of signals therefore takes place between the haploid pollen and diploid tissue of the pistil until fertilization. In compatible interactions, theses processes result in double fertilization to form a zygote (2n) and the triploid endosperm. Among the large number of signaling mechanisms involved, the redox network appears to be particularly important. Respiratory burst oxidase homologs (Rbohs) are superoxide-producing enzymes involved in a broad range of processes in plant physiology. In this study, we review the latest findings on understanding Rboh activity in sexual plant reproduction, with a particular focus on the male gametophyte from the anther development stages to the crowning point of fertilization. Rboh isoforms have been identified in both the male and female gametophyte and have proven to be tightly regulated. Their role at crucial points such as proper growth of pollen tube, self-incompatibility response and eventual fertilization is discussed. PMID:27066025

  7. A Second Superoxide Dismutase Gene in the Medfly, Ceratitis Capitata

    PubMed Central

    Banks, G. K.; Robinson, A. S.; Kwiatowski, J.; Ayala, F. J.; Scott, M. J.; Kriticou, D.

    1995-01-01

    We report the first case of two Cu/Zn Sod genes (ccSod1 and ccSod2) that have been cloned and sequenced from an insect, the medfly, Ceratitis capitata. Biochemical evidence suggested the presence of two Sod genes in the medfly. The two genes are isolated using different molecular strategies: ccSod1 via cross-hybridization to a genomic library using a heterologous probe and ccSod2 from cDNA using a homologous probe generated by PCR. Sequence analysis shows that ccSod1 and ccSod2 are different genes. The inferred amino sequences show that all essential residues of the active site are strictly conserved, which suggests both genes encode functional Cu/Zn superoxide dismutase (SOD). Phylogenetic analysis by the maximum parsimony method with bootstrap resampling of previously known Cu/Zn SOD reveals two monophyletic groups, vertebrates and insects. The position of ccSOD2 in this phylogeny is undefined with respect to dipteran ccSOD1, vertebrate, plant, fungal, and extracellular Cu/Zn SOD, which suggests that the duplication detected in Ceratitis is ancient, perhaps as old as the origins of the arthropod phylum in the Cambrian more than 500 million years ago. In situ hybridization to polytene chromosomes places the genes on different chromosomes, which is consistent with an ancient gene duplication. PMID:7498747

  8. Superoxide dismutase activity of Cu-bound prion protein

    NASA Astrophysics Data System (ADS)

    Hodak, Miroslav; Lu, Wenchang; Bernholc, Jerry

    2009-03-01

    Misfolding of the prion protein, PrP, has been linked to a group of neurodegenerative diseases, including the mad cow disease in cattle and the Creutzfeldt-Jakob disease in humans. The normal function of PrP is still unknown, but it was found that the PrP can efficiently bind Cu(II) ions. Early experiments suggested that Cu-PrP complex possesses significant superoxide dismutase (SOD) activity, but later experiments failed to confirm it and at present this issue remains unresolved. Using a recently developed hybrid DFT/DFT method, which combines Kohn-Sham DFT for the solute and its first solvation shells with orbital-free DFT for the remainder of the solvent, we have investigated SOD activity of PrP. The PrP is capable of incorporating Cu(II) ions in several binding modes and our calculations find that each mode has a different SOD activity. The highest activity found is comparable to those of well-known SOD proteins, suggesting that the conflicting experimental results may be due to different bindings of Cu(II) in those experiments.

  9. Unexpected superoxide dismutase antioxidant activity of ferric chloride in acetonitrile.

    PubMed

    Foti, Mario C; Ingold, K U

    2003-11-14

    The azobis(isobutyronitrile)-initiated autoxidation of gamma-terpinene in acetonitrile at 50 degrees C yields only p-cymene and hydrogen peroxide (1:1) in a chain reaction carried by the hydroperoxyl radical, HOO. (Foti, M. C.; Ingold, K. U. J. Agric. Food Chem. 2003, 51, 2758-2765). This reaction is retarded by very low (microM) concentrations of FeCl(3) and CuCl(2). The kinetics of the FeCl(3)-inhibited autoxidation are consistent with chain-termination via the following: Fe(3+) + HOO. <==>[Fe(IV)-OOH](3+) and [Fe(IV)-OOH](3+) + HOO. --> Fe(3+) + H2O2 + O2. Thus, FeCl(3) in acetonitrile can be regarded as a very effective (and very simple) superoxide dismutase. The kinetics of the CuCl(2)-inhibited autoxidation indicate that chain transfer occurs and becomes more and more important as the reaction proceeds, i.e., the inhibition is replaced by autocatalysis. These kinetics are consistent withreduction of Cu2+ to Cu+ by HOO. and then the reoxidation of Cu+ to Cu2+ by both HOO.and the H2O2 product. The latter reaction yields HO. radicals which continue the chain. PMID:14604404

  10. The superoxide anion donor, potassium superoxide, induces pain and inflammation in mice through production of reactive oxygen species and cyclooxygenase-2.

    PubMed

    Maioli, N A; Zarpelon, A C; Mizokami, S S; Calixto-Campos, C; Guazelli, C F S; Hohmann, M S N; Pinho-Ribeiro, F A; Carvalho, T T; Manchope, M F; Ferraz, C R; Casagrande, R; Verri, W A

    2015-04-01

    It is currently accepted that superoxide anion (O2•-) is an important mediator in pain and inflammation. The role of superoxide anion in pain and inflammation has been mainly determined indirectly by modulating its production and inactivation. Direct evidence using potassium superoxide (KO2), a superoxide anion donor, demonstrated that it induced thermal hyperalgesia, as assessed by the Hargreaves method. However, it remains to be determined whether KO2 is capable of inducing other inflammatory and nociceptive responses attributed to superoxide anion. Therefore, in the present study, we investigated the nociceptive and inflammatory effects of KO2. The KO2-induced inflammatory responses evaluated in mice were: mechanical hyperalgesia (electronic version of von Frey filaments), thermal hyperalgesia (hot plate), edema (caliper rule), myeloperoxidase activity (colorimetric assay), overt pain-like behaviors (flinches, time spent licking and writhing score), leukocyte recruitment, oxidative stress, and cyclooxygenase-2 mRNA expression (quantitative PCR). Administration of KO2 induced mechanical hyperalgesia, thermal hyperalgesia, paw edema, leukocyte recruitment, the writhing response, paw flinching, and paw licking in a dose-dependent manner. KO2 also induced time-dependent cyclooxygenase-2 mRNA expression in the paw skin. The nociceptive, inflammatory, and oxidative stress components of KO2-induced responses were responsive to morphine (analgesic opioid), quercetin (antioxidant flavonoid), and/or celecoxib (anti-inflammatory cyclooxygenase-2 inhibitor) treatment. In conclusion, the well-established superoxide anion donor KO2 is a valuable tool for studying the mechanisms and pharmacological susceptibilities of superoxide anion-triggered nociceptive and inflammatory responses ranging from mechanical and thermal hyperalgesia to overt pain-like behaviors, edema, and leukocyte recruitment.

  11. The superoxide anion donor, potassium superoxide, induces pain and inflammation in mice through production of reactive oxygen species and cyclooxygenase-2

    PubMed Central

    Maioli, N.A.; Zarpelon, A.C.; Mizokami, S.S.; Calixto-Campos, C.; Guazelli, C.F.S.; Hohmann, M.S.N.; Pinho-Ribeiro, F.A.; Carvalho, T.T.; Manchope, M.F.; Ferraz, C.R.; Casagrande, R.; Verri, W.A.

    2015-01-01

    It is currently accepted that superoxide anion (O2 •−) is an important mediator in pain and inflammation. The role of superoxide anion in pain and inflammation has been mainly determined indirectly by modulating its production and inactivation. Direct evidence using potassium superoxide (KO2), a superoxide anion donor, demonstrated that it induced thermal hyperalgesia, as assessed by the Hargreaves method. However, it remains to be determined whether KO2 is capable of inducing other inflammatory and nociceptive responses attributed to superoxide anion. Therefore, in the present study, we investigated the nociceptive and inflammatory effects of KO2. The KO2-induced inflammatory responses evaluated in mice were: mechanical hyperalgesia (electronic version of von Frey filaments), thermal hyperalgesia (hot plate), edema (caliper rule), myeloperoxidase activity (colorimetric assay), overt pain-like behaviors (flinches, time spent licking and writhing score), leukocyte recruitment, oxidative stress, and cyclooxygenase-2 mRNA expression (quantitative PCR). Administration of KO2 induced mechanical hyperalgesia, thermal hyperalgesia, paw edema, leukocyte recruitment, the writhing response, paw flinching, and paw licking in a dose-dependent manner. KO2 also induced time-dependent cyclooxygenase-2 mRNA expression in the paw skin. The nociceptive, inflammatory, and oxidative stress components of KO2-induced responses were responsive to morphine (analgesic opioid), quercetin (antioxidant flavonoid), and/or celecoxib (anti-inflammatory cyclooxygenase-2 inhibitor) treatment. In conclusion, the well-established superoxide anion donor KO2 is a valuable tool for studying the mechanisms and pharmacological susceptibilities of superoxide anion-triggered nociceptive and inflammatory responses ranging from mechanical and thermal hyperalgesia to overt pain-like behaviors, edema, and leukocyte recruitment. PMID:25714890

  12. Cytochemical detection of superoxide in cerebral inflammation and ischemia in vivo.

    PubMed

    Kontos, C D; Wei, E P; Williams, J I; Kontos, H A; Povlishock, J T

    1992-10-01

    We used a cytochemical technique for the detection of superoxide in cerebral inflammation and ischemia-reperfusion in anesthetized cats. The technique is based on the oxidation of Mn2+ to Mn3+ by superoxide; Mn3+, in turn, oxidizes diaminobenzidine. The oxidized diaminobenzidine forms an osmiophilic electron-dense product that is detected by electron microscopy. The reagents, manganese chloride (2 mM) and diaminobenzidine (2 mg/ml), were placed topically on the brain surface of anesthetized cats equipped with cranial windows. Inflammation was induced by topical carrageenan with or without phorbol 12-myristate 13-acetate to activate leukocytes. In inflammation, superoxide was detected in the plasma membrane and in the phagocytic vacuoles of leukocytes. In ischemia-reperfusion, superoxide was identified in the meninges in association with blood vessels. It was located primarily in the extracellular space and occasionally in endothelial and vascular smooth muscle cells. In both inflammation and ischemia, the reaction product was eliminated by superoxide dismutase or by the omission of either manganese or diaminobenzidine. It was unaffected by sodium azide, which inhibits peroxidases. No superoxide was detected in the brain parenchyma. The findings confirm the generation of superoxide is cerebral ischemia-reperfusion and show that it is produced in cerebral vessels.

  13. Biologically relevant mechanism for catalytic superoxide removal by simple manganese compounds

    PubMed Central

    Barnese, Kevin; Gralla, Edith Butler; Valentine, Joan Selverstone; Cabelli, Diane E.

    2012-01-01

    Nonenzymatic manganese was first shown to provide protection against superoxide toxicity in vivo in 1981, but the chemical mechanism responsible for this protection subsequently became controversial due to conflicting reports concerning the ability of Mn to catalyze superoxide disproportionation in vitro. In a recent communication, we reported that low concentrations of a simple Mn phosphate salt under physiologically relevant conditions will indeed catalyze superoxide disproportionation in vitro. We report now that two of the four Mn complexes that are expected to be most abundant in vivo, Mn phosphate and Mn carbonate, can catalyze superoxide disproportionation at physiologically relevant concentrations and pH, whereas Mn pyrophosphate and citrate complexes cannot. Additionally, the chemical mechanisms of these reactions have been studied in detail, and the rates of reactions of the catalytic removal of superoxide by Mn phosphate and carbonate have been modeled. Physiologically relevant concentrations of these compounds were found to be sufficient to mimic an effective concentration of enzymatic superoxide dismutase found in vivo. This mechanism provides a likely explanation as to how Mn combats superoxide stress in cellular systems. PMID:22505740

  14. Effects of asbestos and silica on superoxide anion production in the guinea pig alveolar macrophage

    SciTech Connect

    Roney, P.L.

    1988-01-01

    This study examined the effect of asbestos and silica on the activation pathway of the guinea pig alveolar macrophage. Activation of macrophages by physiological agents results in stimulation of phospholipase C causing phosphatidyl inositol turnover and intracellular calcium mobilization. Phosphatidyl inositol turnover produces diacylglycerol which activates protein kinase C causing superoxide anion production. Chrysotile stimulated alveolar macrophages to produce superoxide anion. This stimulation proceeded via phospholipase C, since chrysotile stimulated phosphatidyl inositol turnover and intracellular calcium mobilization. The possible involvement of a coupling protein was evaluated by pretreating cells with pertussis toxin. Potential binding sites for chrysotile stimulation were examined using a series of nine lectins. Chrysotile-stimulated superoxide anion production was blocked by pretreatment with lectins which bound to mannose, fucose, or N-acetylgalactosamine. In addition, incubation with the N-acetylglucosamine, but not by lectins which bound to mannose, fucose, or N-acetylgalactosamine. In addition, incubation with the N-acetylglucosamine polymer, chitin, inhibited chrysotile-stimulated superoxide anion production, suggesting that chrysotile stimulated superoxide anion production by binding to N-acetylglucosamine residues. On the other hand, silica did not stimulate superoxide anion production. The effect of silica on agonist stimulation of this pathway was examined using two stimulants of superoxide anion production, N-formyl-nle-leu-phe (FNLP, which stimulates through phospholipase C) and phorbol-12,13-dibutyrate (which directly activates protein kinase C).

  15. Evidence for the role of superoxide radicals in neutrophil-mediated cytotoxicity.

    PubMed Central

    Simchowitz, L; Spilberg, I

    1979-01-01

    Human peripheral neutrophils became cytotoxic to chicken red blood cells (CRBC) in the presence of lectins as assessed by release of 51chromium from labelled target cells. Phytohaemagglutinin (PHA) and concanavalin A (Con A), which caused time-dependent and dose-dependent cytotoxicity over a concentration range of 25--400 microgram/ml, also caused significant generation of superoxide radicals as measured by ferricytochrome C reduction. Pokeweed mitogen, which does not induce cytotoxicity over the same concentration range, was unable to promote superoxide generation by neutrophils. PHA-induced generation of superoxide paralleled and appeared to precede PHA-dependent cytotoxicity. Superoxide dismutase (SOD), which enzymatically destroys superoxide, caused moderate inhibition of PHA-dependent cytotoxicity over the concentration range of 100--500 microgram/ml whereas catalytically inactive enzyme had no effect. Incubation under oxygen-depleted conditions caused a marked decrease in both PHA-induced superoxide generation and cytotoxicity relative to that obtained with neutrophils incubated aerobically. These findings suggest a central role for superoxide radicals in causing target cell damage in this model of neutrophil-mediated cytotoxicity. PMID:223976

  16. Biologically Relevant Mechanism For Catalytic Removal of Superoxide by Simple Manganese Compounds

    SciTech Connect

    Barnese K.; Cabelli D.; Gralla, E.B.; Valentine, J.S.

    2012-05-01

    Nonenzymatic manganese was first shown to provide protection against superoxide toxicity in vivo in 1981, but the chemical mechanism responsible for this protection subsequently became controversial due to conflicting reports concerning the ability of Mn to catalyze superoxide disproportionation in vitro. In a recent communication, we reported that low concentrations of a simple Mn phosphate salt under physiologically relevant conditions will indeed catalyze superoxide disproportionation in vitro. We report now that two of the four Mn complexes that are expected to be most abundant in vivo, Mn phosphate and Mn carbonate, can catalyze superoxide disproportionation at physiologically relevant concentrations and pH, whereas Mn pyrophosphate and citrate complexes cannot. Additionally, the chemical mechanisms of these reactions have been studied in detail, and the rates of reactions of the catalytic removal of superoxide by Mn phosphate and carbonate have been modeled. Physiologically relevant concentrations of these compounds were found to be sufficient to mimic an effective concentration of enzymatic superoxide dismutase found in vivo. This mechanism provides a likely explanation as to how Mn combats superoxide stress in cellular systems.

  17. EPR detection of cellular and mitochondrial superoxide using cyclic hydroxylamines.

    PubMed

    Dikalov, Sergey I; Kirilyuk, Igor A; Voinov, Maxim; Grigor'ev, Igor A

    2011-04-01

    Superoxide (O₂ⁱ⁻) has been implicated in the pathogenesis of many human diseases, but detection of the O(2)(•-) radicals in biological systems is limited due to inefficiency of O₂ⁱ⁻ spin trapping and lack of site-specific information. This work studied production of extracellular, intracellular and mitochondrial O₂ⁱ⁻ in neutrophils, cultured endothelial cells and isolated mitochondria using a new set of cationic, anionic and neutral hydroxylamine spin probes with various lipophilicity and cell permeability. Cyclic hydroxylamines rapidly react with O₂ⁱ⁻, producing stable nitroxides and allowing site-specific cO₂ⁱ⁻ detection in intracellular, extracellular and mitochondrial compartments. Negatively charged 1-hydroxy-4-phosphono-oxy-2,2,6,6-tetramethylpiperidine (PP-H) and positively charged 1-hydroxy-2,2,6,6-tetramethylpiperidin-4-yl-trimethylammonium (CAT1-H) detected only extramitochondrial O₂ⁱ⁻. Inhibition of EPR signal by SOD2 over-expression showed that mitochondria targeted mitoTEMPO-H detected intramitochondrial O₂ⁱ⁻ both in isolated mitochondria and intact cells. Both 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CP-H) and 1-hydroxy-3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine (CM-H) detected an increase in cytoplasm O₂ⁱ⁻ stimulated by PMA, but only CM-H and mitoTEMPO-H showed an increase in rotenone-induced mitochondrial O₂ⁱ⁻. These data show that a new set of hydroxylamine spin probes provide unique information about site-specific production of the O₂ⁱ⁻ radical in extracellular or intracellular compartments, cytoplasm or mitochondria.

  18. Manganese superoxide dismutase activity in the rat adrenal.

    PubMed

    Raza, F S; Okamoto, M; Takemori, H; Vinson, G P

    2005-01-01

    In the light of studies suggesting that transcription of the gene coding for manganese superoxide dismutase (MnSOD) is induced by ACTH in the rat adrenal gland, northern blot analysis was used to determine its mRNA distribution. It was found that mRNA coding for MnSOD is primarily present in the inner zones of the rat adrenal cortex, and not the glomerulosa. To investigate the functional relationships between MnSOD activity and expression and adrenocortical function, adrenals and blood were taken from animals pretreated with corticotrophin or betamethasone (Betnesol), or subjected to a low-sodium diet. MnSOD activity in inner zone mitochondrial fractions was enhanced by corticotrophin and by a low-sodium diet, but suppressed by betamethasone. Apparent cytosolic MnSOD activity, total cytosolic MnSOD and CuZnMn-SOD, and glomerulosa mitochondrial MnSOD all were unaffected. Steroid assays showed a clear correlation between circulating corticosterone and inner zone mitochondrial MnSOD, but none between aldosterone and glomerulosa MnSOD. Immunoblot analysis of MnSOD showed two apparent isoforms, at approximately 25 kDa and 75 kDa. There was a partial relationship between expression of the 75 kDa isoform and MnSOD activity, in that it was induced by corticotrophin. However, there was also a slight induction with betamethasone, and a low-sodium diet had no effect. The 25 kDa MnSOD isoform was unaffected by the treatments. The results suggest that MnSOD may have a specific role in the steroidogenic function of the fasciculata/reticularis of the rat adrenal, but not in that of the glomerulosa.

  19. Superoxide fluxes limit nitric oxide-induced signaling.

    PubMed

    Thomas, Douglas D; Ridnour, Lisa A; Espey, Michael Graham; Donzelli, Sonia; Ambs, Stefan; Hussain, S Perwez; Harris, Curtis C; DeGraff, William; Roberts, David D; Mitchell, James B; Wink, David A

    2006-09-01

    Independently, superoxide (O2-) and nitric oxide (NO) are biologically important signaling molecules. When co-generated, these radicals react rapidly to form powerful oxidizing and nitrating intermediates. Although this reaction was once thought to be solely cytotoxic, herein we demonstrate using MCF7, macrophage, and endothelial cells that when nanomolar levels of NO and O2- were produced concomitantly, the effective NO concentration was established by the relative fluxes of these two radicals. Differential regulation of sGC, pERK, HIF-1alpha, and p53 were used as biological dosimeters for NO concentration. Introduction of intracellular- or extracellular-generated O2- during NO generation resulted in a concomitant increase in oxidative intermediates with a decrease in steady-state NO concentrations and a proportional reduction in the levels of sGC, ERK, HIF-1alpha, and p53 regulation. NO responses were restored by addition of SOD. The intermediates formed from the reactions of NO with O2- were non-toxic, did not form 3-nitrotyrosine, nor did they elicit any signal transduction responses. H2O2 in bolus or generated from the dismutation of O2- by SOD, was cytotoxic at high concentrations and activated p53 independent of NO. This effect was completely inhibited by catalase, suppressed by NO, and exacerbated by intracellular catalase inhibition. We conclude that the reaction of O2- with NO is an important regulatory mechanism, which modulates signaling pathways by limiting steady-state levels of NO and preventing H2O2 formation from O2-.

  20. Cytosolic superoxide dismutase can provide protection against Fasciola gigantica.

    PubMed

    Jaikua, Wipaphorn; Kueakhai, Pornanan; Chaithirayanon, Kulathida; Tanomrat, Rataya; Wongwairot, Sirima; Riengrojpitak, Suda; Sobhon, Prasert; Changklungmoa, Narin

    2016-10-01

    Superoxide dismutases (SOD), antioxidant metallo-enzymes, are a part of the first line of defense in the trematode parasites which act as the chief scavengers for reactive oxygen species (ROS). A recombinant Fasciola gigantica cytosolic SOD (FgSOD) was expressed in Escherichia coli BL21 (DE3) and used for immunizing rabbits to obtain polyclonal antibodies (anti-rFgSOD). This rabbit anti-rFgSOD reacted with the native FgSOD at a molecular weight of 17.5kDa. The FgSOD protein was expressed at high level in parenchyma, caecal epithelium and egg of the parasite. The rFgSOD reacted with antisera from rabbits infected with F. gigantica metacercariae collected at 2, 5, and 7 weeks after infection, and reacted with sera of infected mice. Anti-rFgSOD exhibited cross reactivity with the other parasites' antigens, including Eurytrema pancreaticum, Cotylophoron cotylophorum, Fischoederius cobboldi, Gastrothylax crumenifer, Paramphistomum cervi, and Setaria labiato papillosa. A vaccination was performed in imprinting control region (ICR) mice by subcutaneous injection with 50μg of rFgSOD combined with Freund's adjuvant. At 2 weeks after the second boost, mice were infected with 15 metacercariae by oral route. IgG1 and IgG2a in the immune sera were determined to indicate Th2 and Th1 immune responses. It was found that the parasite burden was reduced by 45%, and both IgG1 and IgG2a levels showed correlation with the numbers of worm recoveries. PMID:27338185

  1. Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

    PubMed Central

    Hansel, Colleen M.; Zeiner, Carolyn A.; Santelli, Cara M.; Webb, Samuel M.

    2012-01-01

    Manganese (Mn) oxides are among the most reactive minerals within the environment, where they control the bioavailability of carbon, nutrients, and numerous metals. Although the ability of microorganisms to oxidize Mn(II) to Mn(III/IV) oxides is scattered throughout the bacterial and fungal domains of life, the mechanism and physiological basis for Mn(II) oxidation remains an enigma. Here, we use a combination of compound-specific chemical assays, microspectroscopy, and electron microscopy to show that a common Ascomycete filamentous fungus, Stilbella aciculosa, oxidizes Mn(II) to Mn oxides by producing extracellular superoxide during cell differentiation. The reactive Mn oxide phase birnessite and the reactive oxygen species superoxide and hydrogen peroxide are colocalized at the base of asexual reproductive structures. Mn oxide formation is not observed in the presence of superoxide scavengers (e.g., Cu) and inhibitors of NADPH oxidases (e.g., diphenylene iodonium chloride), enzymes responsible for superoxide production and cell differentiation in fungi. Considering the recent identification of Mn(II) oxidation by NADH oxidase-based superoxide production by a common marine bacterium (Roseobacter sp.), these results introduce a surprising homology between some prokaryotic and eukaryotic organisms in the mechanisms responsible for Mn(II) oxidation, where oxidation appears to be a side reaction of extracellular superoxide production. Given the versatility of superoxide as a redox reactant and the widespread ability of fungi to produce superoxide, this microbial extracellular superoxide production may play a central role in the cycling and bioavailability of metals (e.g., Hg, Fe, Mn) and carbon in natural systems. PMID:22802654

  2. Ceruloplasmin copper induces oxidant damage by a redox process utilizing cell-derived superoxide as reductant

    NASA Technical Reports Server (NTRS)

    Mukhopadhyay, C. K.; Fox, P. L.

    1998-01-01

    Oxidative damage by transition metals bound to proteins may be an important pathogenic mechanism. Ceruloplasmin (Cp) is a Cu-containing plasma protein thought to be involved in oxidative modification of lipoproteins. We have previously shown that Cp increased cell-mediated low-density lipoprotein (LDL) oxidation by a process requiring cell-derived superoxide, but the underlying chemical mechanism(s) is (are) unknown. We now show that superoxide reduction of Cp Cu is a critical reaction in cellular LDL oxidation. By bathocuproine disulfonate (BCS) binding and by superoxide utilization, we showed that exogenous superoxide reduces a single Cp Cu atom, the same Cu required for LDL oxidation. The Cu atom remained bound to Cp during the redox cycle. Three avenues of evidence showed that vascular cells reduce Cp Cu by a superoxide-dependent process. The 2-fold higher rate of Cp Cu reduction by smooth muscle cells (SMC) compared to endothelial cells (EC) was consistent with their relative rates of superoxide release. Furthermore, Cp Cu reduction by cells was blocked by Cu,Zn superoxide dismutase (SOD1). Finally, the level of superoxide produced by EC and SMC was sufficient to cause the amount of Cu reduction observed. An important role of Cp Cu reduction in LDL oxidation was suggested by results showing that SOD1 inhibited Cp Cu reduction and LDL oxidation by SMC with equal potency, while tumor necrosis factor-alpha stimulated both processes. In summary, these results show that superoxide is a critical cellular reductant of divalent transition metals involved in oxidation, and that protein-bound Cu is a substrate for this reaction. The role of these mechanisms in oxidative processes in vivo has yet to be defined.

  3. Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction.

    PubMed

    Hansel, Colleen M; Zeiner, Carolyn A; Santelli, Cara M; Webb, Samuel M

    2012-07-31

    Manganese (Mn) oxides are among the most reactive minerals within the environment, where they control the bioavailability of carbon, nutrients, and numerous metals. Although the ability of microorganisms to oxidize Mn(II) to Mn(III/IV) oxides is scattered throughout the bacterial and fungal domains of life, the mechanism and physiological basis for Mn(II) oxidation remains an enigma. Here, we use a combination of compound-specific chemical assays, microspectroscopy, and electron microscopy to show that a common Ascomycete filamentous fungus, Stilbella aciculosa, oxidizes Mn(II) to Mn oxides by producing extracellular superoxide during cell differentiation. The reactive Mn oxide phase birnessite and the reactive oxygen species superoxide and hydrogen peroxide are colocalized at the base of asexual reproductive structures. Mn oxide formation is not observed in the presence of superoxide scavengers (e.g., Cu) and inhibitors of NADPH oxidases (e.g., diphenylene iodonium chloride), enzymes responsible for superoxide production and cell differentiation in fungi. Considering the recent identification of Mn(II) oxidation by NADH oxidase-based superoxide production by a common marine bacterium (Roseobacter sp.), these results introduce a surprising homology between some prokaryotic and eukaryotic organisms in the mechanisms responsible for Mn(II) oxidation, where oxidation appears to be a side reaction of extracellular superoxide production. Given the versatility of superoxide as a redox reactant and the widespread ability of fungi to produce superoxide, this microbial extracellular superoxide production may play a central role in the cycling and bioavailability of metals (e.g., Hg, Fe, Mn) and carbon in natural systems.

  4. Mn(II) oxidation by an ascomycete fungus is linked to superoxide production during asexual reproduction

    SciTech Connect

    Hansel, C. M.; Zeiner, C. A.; Santelli, C. M.; Webb, S. M.

    2012-07-16

    Manganese (Mn) oxides are among the most reactive minerals within the environment, where they control the bioavailability of carbon, nutrients, and numerous metals. Although the ability of microorganisms to oxidize Mn(II) to Mn(III/IV) oxides is scattered throughout the bacterial and fungal domains of life, the mechanism and physiological basis for Mn(II) oxidation remains an enigma. Here, we use a combination of compound-specific chemical assays, microspectroscopy, and electron microscopy to show that a common Ascomycete filamentous fungus, Stilbella aciculosa, oxidizes Mn(II) to Mn oxides by producing extracellular superoxide during cell differentiation. The reactive Mn oxide phase birnessite and the reactive oxygen species superoxide and hydrogen peroxide are colocalized at the base of asexual reproductive structures. Mn oxide formation is not observed in the presence of superoxide scavengers (e.g., Cu) and inhibitors of NADPH oxidases (e.g., diphenylene iodonium chloride), enzymes responsible for superoxide production and cell differentiation in fungi. Considering the recent identification of Mn(II) oxidation by NADH oxidase-based superoxide production by a common marine bacterium (Roseobacter sp.), these results introduce a surprising homology between some prokaryotic and eukaryotic organisms in the mechanisms responsible for Mn(II) oxidation, where oxidation appears to be a side reaction of extracellular superoxide production. Finally, given the versatility of superoxide as a redox reactant and the widespread ability of fungi to produce superoxide, this microbial extracellular superoxide production may play a central role in the cycling and bioavailability of metals (e.g., Hg, Fe, Mn) and carbon in natural systems.

  5. Histamine-3 receptor antagonists reduce superoxide anion generation and lipid peroxidation in rat brain homogenates.

    PubMed

    Badenhorst, H E; Maharaj, D S; Malan, S F; Daya, S; van Dyk, S

    2005-06-01

    Using a cyanide model to induce neurotoxic effects in rat brain homogenates, we examined the neuroprotective properties of three H3 antagonists, namely clobenpropit, thioperamide and impentamine, and compared them to aspirin, a known neuroprotective agent. Superoxide anion levels and malondialdehyde concentration were assessed using the nitroblue tetrazolium and lipid peroxidation assays. Clobenpropit and thioperamide significantly reduced superoxide anion generation and lipid peroxidation. Impentamine reduced lipid peroxidation at all concentrations used, but only reduced superoxide anion generation at a concentration of 1 mM. In the lipid peroxidation assay, all the drugs compared favourably to aspirin. This study demonstrates the potential of these agents to be neuroprotective by exerting antioxidant effects.

  6. Molecular cloning and expression patterns of copper/zinc superoxide dismutase and manganese superoxide dismutase in Musca domestica.

    PubMed

    Tang, Ting; Huang, Da-Wei; Zhou, Chuan-Qi; Li, Xiang; Xie, Qi-Jing; Liu, Feng-Song

    2012-09-01

    Superoxide dismutases (SODs) are metalloenzymes that represent one important line of defense against reactive oxygen species (ROS). In this paper, two novel SOD genes, MdSOD1 and MdSOD2, which putatively encode 261 and 214 amino acid residues respectively were identified and characterized from the housefly Musca domestica. The high similarity of MdSOD1 and MdSOD2 with SODs from other organisms indicated that they should be two new members of the SOD family. qPCR exhibited a universal expression of MdSOD1 and MdSOD2 detected in various tissues of housefly larva, including the fat body, gut, hemocyte and epidermis. Expression profiling reveals that MdSOD1 and MdSOD2 can be induced significantly via not only heat shock and cadmium (Cd) stress but also Escherichia coli and Staphylococcus aureus challenge. The two genes were cloned into the prokaryotic expression vector pET-28a to obtain the fusion proteins rMdSOD1 and rMdSOD2. Between them, the activity of rMdSOD2 was found by visual assay methods. ESI-LC-MS/MS analysis showed that three peptide fragments of the protein rMdSOD2 were identical to the corresponding sequence of M. domestica MdSOD2. MdSOD1 and MdSOD2 in housefly larvae were abrogated by feeding bacteria expressing dsRNA. High mortalities were observed in the larvae treated with dsRNA of SODs at heat shock, Cd stress and bacterial invasion. This phenomenon indicated that MdSOD1 and MdSOD2 are related to the survival of M. domestica under stress. This may provide new insights into the role of the two SOD genes in protecting M. domestica against both stress and bacterial invasion. PMID:22750315

  7. Structures of two superoxide dismutases from Bacillus anthracis reveal a novel active centre

    SciTech Connect

    Boucher, Ian W.; Kalliomaa, Anne K.; Levdikov, Vladimir M.; Blagova, Elena V.; Fogg, Mark J.; Brannigan, James A. Wilson, Keith S.; Wilkinson, Anthony J.

    2005-07-01

    The crystal structures of two manganese superoxide dismutases from B. anthracis were solved by X-ray crystallography using molecular replacement. The BA4499 and BA5696 genes of Bacillus anthracis encode proteins homologous to manganese superoxide dismutase, suggesting that this organism has an expanded repertoire of antioxidant proteins. Differences in metal specificity and quaternary structure between the dismutases of prokaryotes and higher eukaryotes may be exploited in the development of therapeutic antibacterial compounds. Here, the crystal structure of two Mn superoxide dismutases from B. anthracis solved to high resolution are reported. Comparison of their structures reveals that a highly conserved residue near the active centre is substituted in one of the proteins and that this is a characteristic feature of superoxide dismutases from the B. cereus/B. anthracis/B. thuringiensis group of organisms.

  8. Role of superoxide in renal scarring following infection by mannose-sensitive piliated bacteria.

    PubMed

    Matsumoto, T; Mizunoe, Y; Ogata, N; Tanaka, M; Kumazawa, J

    1991-01-01

    The role of superoxide in scar formation following renal infection caused by mannose-sensitive (MS) piliated strains of bacteria was studied in the experimental pyelonephritis model using female Sprague-Dawley rats. The MS piliated strain stimulated renal scarring to a significantly greater extent than either the non-piliated or MR-piliated strain. Modulation of leukocytes by administering cyclophosphamide to induce neutropenia and colchicine to inhibit leukocyte migration was effective in preventing renal scarring. Treatment with superoxide dismutase during the early stage of infection was also effective in preventing scar formation. Finally, the production of superoxide by rat leukocytes was significantly larger following stimulation by MS piliated than either the non-piliated or MR piliated strains. These observations suggest that superoxide released from leukocytes plays a critical role in the development of renal scarring following a bacterial infection, especially by MS piliated strains.

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

    NASA Technical Reports Server (NTRS)

    Borgstahl, Gloria; Snell, Edward H.

    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.

  10. Chloramphenicol Mediates Superoxide Production in Photosystem II and Enhances Its Photodamage in Isolated Membrane Particles

    PubMed Central

    Rehman, Ateeq Ur; Kodru, Sandeesha; Vass, Imre

    2016-01-01

    Chloramphenicol (CAP) is an inhibitor of protein synthesis, which is frequently used to decouple photodamage and protein synthesis dependent repair of Photosystem II during the process of photoinhibition. It has been reported earlier that CAP is able to mediate superoxide production by transferring electrons from the acceptor side of Photosystem I to oxygen. Here we investigated the interaction of CAP with Photosystem II electron transport processes by oxygen uptake and variable chlorophyll fluorescence measurements. Our data show that CAP can accept electrons at the acceptor side of Photosystem II, most likely from Pheophytin, and deliver them to molecular oxygen leading to superoxide production. In addition, the presence of CAP enhances photodamage of Photosystem II electron transport in isolated membrane particles, which effect is reversible by superoxide dismutase. It is concluded that CAP acts as electron acceptor in Photosystem II and mediates its superoxide dependent photodamage. This effect has potential implications for the application of CAP in photoinhibitory studies in intact systems. PMID:27092170

  11. Purification of human copper, zinc superoxide dismutase by copper chelate affinity chromatography

    SciTech Connect

    Weslake, R.J.; Chesney, S.L.; Petkau, A.; Friesen, A.D.

    1986-05-15

    Copper, zinc superoxide dismutase was isolated from human red blood cell hemolysate by DEAE-Sepharose and copper chelate affinity chromatography. Enzyme preparations had specific activities ranging from 3400 to 3800 U/mg and recoveries were approximately 60% of the enzyme activity in the lysate. Copper chelate affinity chromatography resulted in a purification factor of about 60-fold. The homogeneity of the superoxide dismutase preparation was analyzed by sodium dodecyl sulfate-gel electrophoresis, analytical gel filtration chromatography, and isoelectric focusing.

  12. Catalase and Superoxide Dismutase of Root-Colonizing Saprophytic Fluorescent Pseudomonads †

    PubMed Central

    Katsuwon, Jirasak; Anderson, Anne J.

    1990-01-01

    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. Increased specific activities of catalase but not superoxide dismutase were observed during growth of these bacteria on components washed from root surfaces. The specific activities of both enzymes were also regulated during contact of these bacteria with intact bean roots. Increased superoxide dismutase and decreased catalase activities were observed rapidly, by 10 min upon inoculation of cells onto intact bean roots. Catalase specific activity increased with time to peak at 12 h before declining. By 48 h, the cells displayed this low catalase but maintained high superoxide dismutase specific activities. Catalase with a low specific activity and a high superoxide dismutase activity also were present in extracts of cells obtained from 7-day-old roots colonized from inoculum applied to seed. This specific activity of superoxide dismutase of root-contacted cells was about fourfold-higher in comparison to cells grown on rich medium, whereas the specific activity for catalase was reduced about fivefold. A single catalase isozyme, isozyme A, and one isozyme of superoxide dismutase, isozyme 1, were detected during growth of the bacteria on root surface components and during exposure of cells to intact bean roots for 1 h. An additional catalase, isozyme B, was detected from bacteria after exposure to the intact bean roots for 12 h. Catalase isozyme A and superoxide dismutase isozyme 1 were located in the cytoplasm and catalase band B was located in the membrane of P. putida. Images PMID:16348360

  13. Superoxide Dismutase and Oxygen Metabolism in Streptococcus faecalis and Comparisons with Other Organisms

    PubMed Central

    Britton, Larry; Malinowski, Douglas P.; Fridovich, Irwin

    1978-01-01

    Streptococcus faecalis contains a single superoxide dismutase that has been purified to homogeneity with a 55% yield. This enzyme has a molecular weight of 45,000 and is composed of two subunits of equal size. It contains 1.3 atoms of manganese per molecule. Its amino acid composition was determined and is compared with that for the superoxide dismutases from Escherichia coli, Streptococcus mutans, and Mycobacterium lepraemurium. When used as an antigen in rabbits, the S. faecalis enzyme elicited the formation of a precipitating and inhibiting antibody. This antibody cross-reacted with the superoxide dismutase present in another strain of S. faecalis, but neither inhibited nor precipitated the superoxide dismutases in a wide range of other bacteria, including several other streptococci, such as S. pyogenes, S. pneumoniae, and S. lactis. The inhibiting antibody was used to suppress the superoxide dismutase activity present in cell extracts of S. faecalis and thus allow the demonstration that 17% of the total oxygen consumption by such extracts, in the presence of reduced nicotinamide adenine dinucleotide, was associated with the production of O2−. A variety of bacterial species were surveyed for their content of superoxide dismutases. The iron-containing enzyme was distinguished from the manganese-containing enzyme through the use of H2O2, which inactivates the former more readily than the latter. Some of the bacteria appeared to contain only the iron enzyme, others only the manganese enzyme, and still others both. Indeed, some had multiple, electrophoretically distinct superoxide dismutases in both categories. There was no discernible absolute relationship between the types of superoxide dismutases in a particular organism and their Gram-stain reaction. Images PMID:206536

  14. Superoxide enhances Ca2+ entry through L-type channels in the renal afferent arteriole.

    PubMed

    Vogel, Paul A; Yang, Xi; Moss, Nicholas G; Arendshorst, William J

    2015-08-01

    Reactive oxygen species regulate cardiovascular and renal function in health and disease. Superoxide participates in acute calcium signaling in afferent arterioles and renal vasoconstriction produced by angiotensin II, endothelin, thromboxane, and pressure-induced myogenic tone. Known mechanisms by which superoxide acts include quenching of nitric oxide and increased ADP ribosyl cyclase/ryanodine-mediated calcium mobilization. The effect(s) of superoxide on other calcium signaling pathways in the renal microcirculation is poorly understood. The present experiments examined the acute effect of superoxide generated by paraquat on calcium entry pathways in isolated rat afferent arterioles. The peak increase in cytosolic calcium concentration caused by KCl (40 mmol/L) was 99±14 nmol/L. The response to this membrane depolarization was mediated exclusively by L-type channels because it was abolished by nifedipine but was unaffected by the T-type channel blocker mibefradil. Paraquat increased superoxide production (dihydroethidium fluorescence), tripled the peak response to KCl to 314±68 nmol/L (P<0.001) and doubled the plateau response. These effects were abolished by tempol and nitroblue tetrazolium, but not by catalase, confirming actions of superoxide and not of hydrogen peroxide. Unaffected by paraquat and superoxide was calcium entry through store-operated calcium channels activated by thapsigargin-induced calcium depletion of sarcoplasmic reticular stores. Also unresponsive to paraquat was ryanodine receptor-mediated calcium-induced calcium release from the sarcoplasmic reticulum. Our results provide new evidence that superoxide enhances calcium entry through L-type channels activated by membrane depolarization in rat cortical afferent arterioles, without affecting calcium entry through store-operated entry or ryanodine receptor-mediated calcium mobilization. PMID:26034201

  15. The effect of tilmicosin on cardiac superoxide dismutase and glutathione peroxidase activities.

    PubMed

    Yazar, E; Altunok, V; Elmas, M; Traş, B; Baş, A L; Ozdemir, V

    2002-05-01

    In this study, the effect of tilmicosin on cardiac superoxide dismutase and glutathione peroxidase activities was investigated. Forty male BALB/c mice were used as material. Ten mice served as a control group, and 30 mice were injected with tilmicosin (25 mg/kg body weight, subcutaneously, with a single injection). After drug administration, they were monitored for 3 days. Tilmicosin caused decreases in cardiac superoxide dismutase and glutathione peroxidase activities.

  16. Chemiluminescence Imaging of Superoxide Anion Detects Beta-Cell Function and Mass

    PubMed Central

    Bronsart, Laura L.; Stokes, Christian; Contag, Christopher H.

    2016-01-01

    Superoxide anion is produced during normal cellular respiration and plays key roles in cellular physiology with its dysregulation being associated with a variety of diseases. Superoxide anion is a short-lived molecule and, therefore, its homeostatic regulation and role in biology and disease requires dynamic quantification with fine temporal resolution. Here we validated coelenterazine as a reporter of intracellular superoxide anion concentration and used it as a dynamic measure both in vitro and in vivo. Chemiluminescence was dependent upon superoxide anion levels, including those produced during cellular respiration, and concentrations varied both kinetically and temporally in response to physiologically relevant fluctuations in glucose levels. In vivo imaging with coelenterazine revealed that beta cells of the pancreas have increased levels of superoxide anion, which acted as a measure of beta-cell function and mass and could predict the susceptibility of mice to diabetes mellitus. Glucose response and regulation are key elements of cellular physiology and organismal biology, and superoxide anion appears to play a fundamental and dynamic role in both of these processes. PMID:26752052

  17. Chemiluminescence Imaging of Superoxide Anion Detects Beta-Cell Function and Mass.

    PubMed

    Bronsart, Laura L; Stokes, Christian; Contag, Christopher H

    2016-01-01

    Superoxide anion is produced during normal cellular respiration and plays key roles in cellular physiology with its dysregulation being associated with a variety of diseases. Superoxide anion is a short-lived molecule and, therefore, its homeostatic regulation and role in biology and disease requires dynamic quantification with fine temporal resolution. Here we validated coelenterazine as a reporter of intracellular superoxide anion concentration and used it as a dynamic measure both in vitro and in vivo. Chemiluminescence was dependent upon superoxide anion levels, including those produced during cellular respiration, and concentrations varied both kinetically and temporally in response to physiologically relevant fluctuations in glucose levels. In vivo imaging with coelenterazine revealed that beta cells of the pancreas have increased levels of superoxide anion, which acted as a measure of beta-cell function and mass and could predict the susceptibility of mice to diabetes mellitus. Glucose response and regulation are key elements of cellular physiology and organismal biology, and superoxide anion appears to play a fundamental and dynamic role in both of these processes. PMID:26752052

  18. Serine protease inhibitors block priming of monocytes for enhanced release of superoxide.

    PubMed Central

    Megyeri, P; Pabst, K M; Pabst, M J

    1995-01-01

    Monocytes freshly isolated from human blood produced large amounts of superoxide when triggered by phorbol ester. After monocytes were cultured for 18-24 hr in endotoxin-free, non-adherent conditions, they produced low amounts of superoxide. Addition of lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), or platelet-activating factor (PAF) at the beginning of culture 'primed' the monocytes, causing them to maintain a high superoxide response for at least 96 hr. Also, in response to LPS, monocytes secreted TNF-alpha. The ability of LPS, IFN-gamma, TNF-alpha or PAF to maintain the high superoxide response was blocked by addition of inhibitors of serine proteases, either 4-(2-aminoethyl)-benzenesulphonyl fluoride (AEBSF) or 3,4-dichloroisocoumarin. AEBSF was most effective at 200 microns, and required 6 hr for maximum effect. AEBSF did not affect phorbol-triggered superoxide release by unprimed monocytes. AEBSF did not affect cell viability, nor did it interfere with the TNF-alpha secretion in response to LPS. An analogue of AEBSF that lacked ability to inhibit proteases did not affect monocyte responses. 3,4-Dichloroisocoumarin blocked priming at a low concentration, 1 microM. We conclude that activity of a monocyte serine protease is required to maintain the high superoxide response in monocytes primed with LPS, IFN-gamma, TNF-alpha, or PAF. PMID:8567031

  19. A novel superoxide dismutase from Cicer arietinum L. seedlings: isolation, purification and characterization.

    PubMed

    Singh, Sushant; Singh, Abhay Narayan; Verma, Anil; Dubey, Vikash Kumar

    2013-07-01

    Superoxide dismutase is an important enzyme with various therapeutic applications. Search of a new source of superoxide dismutase with novel properties has significant importance. The current work reports purification of a novel superoxide dismutase enzyme with unique characteristics. A copper zinc superoxide dismutase (Cu-Zn SOD) was purified and characterized from Cicer arietinum L. seedlings germinated under aluminium (Al+3) stress. The specific activity of purified protein was 158 units/mg with 28 fold purification. The superoxide dismutase is a homodimeric protein with approx subunit molecular weight of 33.27 kDa. The enzyme is identified as Cu-Zn category of superoxide dismutase, reflected by H2O2 induced inhibition of in-gel activity and presence of quantifiable copper and zinc ions. The optimum pH range for purified Cu-Zn SOD activity was observed within 6.5-8.5 (highest at pH 8.0) and the pH stability was in the range of 6.0-8.5. The enzyme was more stable at low temperature (below 30°C) and the Km of purified Cu-Zn SOD for riboflavin as substrate was 10.16 ± 2.5 µM. The N-terminal amino acid sequence showed homology at conserved residues with other plant Cu-Zn SODs.

  20. Mechanisms of Superoxide Signaling in Epigenetic Processes: Relation to Aging and Cancer

    PubMed Central

    Afanas’ev, Igor

    2015-01-01

    Superoxide is a precursor of many free radicals and reactive oxygen species (ROS) in biological systems. It has been shown that superoxide regulates major epigenetic processes of DNA methylation, histone methylation, and histone acetylation. We suggested that superoxide, being a radical anion and a strong nucleophile, could participate in DNA methylation and histone methylation and acetylation through mechanism of nucleophilic substitution and free radical abstraction. In nucleophilic reactions superoxide is able to neutralize positive charges of methyl donors S-adenosyl-L-methionine (SAM) and acetyl-coenzyme A (AcCoA) enhancing their nucleophilic capacity or to deprotonate cytosine. In the reversed free radical reactions of demethylation and deacetylation superoxide is formed catalytically by the (Tet) family of dioxygenates and converted into the iron form of hydroxyl radical with subsequent oxidation and final eradication of methyl substituents. Double role of superoxide in these epigenetic processes might be of importance for understanding of ROS effects under physiological and pathological conditions including cancer and aging. PMID:26029480

  1. Real time in vivo investigation of superoxide dynamics in zebrafish liver using a single-fiber fluorescent probe

    PubMed Central

    Chang, Yu-Chung; Ken, Chuian-Fu; Hsu, Che-Wei; Liu, Ya-Ging

    2013-01-01

    Superoxide anion is the key radical that causes intracellular oxidative stress. The lack of a method to directly monitor superoxide concentration in vivo in real time has severely hindered our understanding on its pathophysiology. We made transgenic zebrafish to specifically express yellow fluorescent proteins, a reversible superoxide-specific indicator, in the liver and used a fiber-optic fluorescent probe to noninvasively monitor the superoxide concentration in real time. Several superoxide-inducing and scavenging reagents were administrated onto the fish to alter superoxide concentrations. The distinct biochemical pathways of the reagents can be discerned from the transient behaviors of fluorescence time courses. These results demonstrate the feasibility of this method for analyzing superoxide dynamics and its potential as an in vivo pharmaceutical screening platform. PMID:24049691

  2. Induction of superoxide dismutases in Escherichia coli by manganese and iron

    SciTech Connect

    Pugh, S.Y.R.; DiGuiseppi, J.L.; Fridovich, I.

    1984-10-01

    Growth of Escherichia coli B in simple media enriched with Mn(II) resulted in the elevation of the manganese-containing superoxide dismutase, whereas growth in such medium enriched with iron caused increased content of the iron-containing superoxide dismutase. Enrichment of the medium with Co(II), Cu(II), Mo(VI), Zn(II), or Ni(II) had no effect. The inductions of superoxide dismutase by Mn(II) or by Fe(II) were dioxygen dependent, but these metals did not affect the CN/sup -/-resistant respiration of E. coli B and did not influence the increase in the CN/sup -/-resistant respiration caused by paraquat. Mn(II) and paraquat acted synergistically in elevating the superoxide dismutase content, and Mn(II) reduced the growth inhibition imposed by paraquat. E. coli grown in the complex 3% Trypticase soy broth (BBL Microbiology Systems)-0.5% yeast extract-0.2% glucose medium contained more superoxide dismutase than did cells grown in the simple media and were less responsive to enrichment of the medium with Mn(II) or Fe(II). Nevertheless, in the presence of paraquat, induction of superoxide dismutase by these metals could be seen even in the Trypticase-yeast extract-glucose medium. On the basis of these observations, the authors propose that the apo-superoxide dismutases may act as autogenous repressors and that Mn(II) and Fe(II) increase the cell content of the corresponding enzymes by speeding the conversion of the apo- to the holoenzymes.

  3. NFAT is required for spontaneous pulmonary hypertension in superoxide dismutase 1 knockout mice.

    PubMed

    Ramiro-Diaz, Juan Manuel; Nitta, Carlos H; Maston, Levi D; Codianni, Simon; Giermakowska, Wieslawa; Resta, Thomas C; Gonzalez Bosc, Laura V

    2013-05-01

    Elevated reactive oxygen species are implicated in pulmonary hypertension (PH). Superoxide dismutase (SOD) limits superoxide bioavailability, and decreased SOD activity is associated with PH. A decrease in SOD activity is expected to increase superoxide and reduce hydrogen peroxide levels. Such an imbalance of superoxide/hydrogen peroxide has been implicated as a mediator of nuclear factor of activated T cells (NFAT) activation in epidermal cells. We have shown that NFATc3 is required for chronic hypoxia-induced PH. However, it is unknown whether NFATc3 is activated in the pulmonary circulation in a mouse model of decreased SOD1 activity and whether this leads to PH. Therefore, we hypothesized that an elevated pulmonary arterial superoxide/hydrogen peroxide ratio activates NFATc3, leading to PH. We found that SOD1 knockout (KO) mice have elevated pulmonary arterial wall superoxide and decreased hydrogen peroxide levels compared with wild-type (WT) littermates. Right ventricular systolic pressure (RVSP) was elevated in SOD1 KO and was associated with pulmonary arterial remodeling. Vasoreactivity to endothelin-1 was also greater in SOD1 KO vs. WT mice. NFAT activity and NFATc3 nuclear localization were increased in pulmonary arteries from SOD1 KO vs. WT mice. Administration of A-285222 (selective NFAT inhibitor) decreased RVSP, arterial wall thickness, vasoreactivity, and NFAT activity in SOD1 KO mice to WT levels. The SOD mimetic, tempol, also reduced NFAT activity, NFATc3 nuclear localization, and RVSP to WT levels. These findings suggest that an elevated superoxide/hydrogen peroxide ratio activates NFAT in pulmonary arteries, which induces vascular remodeling and increases vascular reactivity leading to PH.

  4. Evidence for two sites of superoxide production by mitochondrial NADH-ubiquinone oxidoreductase (complex I).

    PubMed

    Treberg, Jason R; Quinlan, Casey L; Brand, Martin D

    2011-08-01

    Complex I (NADH-ubiquinone oxidoreductase) can form superoxide during forward electron flow (NADH-oxidizing) or, at sufficiently high protonmotive force, during reverse electron transport from the ubiquinone (Q) pool (NAD(+)-reducing). We designed an assay system to allow titration of the redox state of the superoxide-generating site during reverse electron transport in rat skeletal muscle mitochondria: a protonmotive force generated by ATP hydrolysis, succinate:malonate to alter electron supply and modulate the redox state of the Q pool, and inhibition of complex III to prevent QH(2) oxidation via the Q cycle. Stepwise oxidation of the QH(2)/Q pool by increasing malonate concentration slowed the rates of both reverse electron transport and rotenone-sensitive superoxide production by complex I. However, the superoxide production rate was not uniquely related to the resultant potential of the NADH/NAD(+) redox couple. Thus, there is a superoxide producer during reverse electron transport at complex I that responds to Q pool redox state and is not in equilibrium with the NAD reduction state. In contrast, superoxide production during forward electron transport in the presence of rotenone was uniquely related to NAD redox state. These results support a two-site model of complex I superoxide production; one site in equilibrium with the NAD pool, presumably the flavin of the FMN moiety (site I(F)) and the other dependent not only on NAD redox state, but also on protonmotive force and the reduction state of the Q pool, presumably a semiquinone in the Q-binding site (site I(Q)). PMID:21659507

  5. Hypoxia, reoxygenation and cytosolic manganese superoxide dismutase (cMnSOD) silencing in Litopenaeus vannamei: effects on cMnSOD transcripts, superoxide dismutase activity and superoxide anion production capacity.

    PubMed

    García-Triana, Antonio; Zenteno-Savín, Tania; Peregrino-Uriarte, Alma Beatriz; Yepiz-Plascencia, Gloria

    2010-11-01

    The effects of silencing the mRNA of cytosolic manganese superoxide dismutase (cMnSOD), an enzyme involved in the antioxidant defense, were analyzed in Whiteleg shrimp, Litopenaeus vannamei adults. Shrimp were intramuscularly injected with long dsRNAs corresponding to the N-terminal portion of the cMnSOD and held under normoxic conditions for 24h. Another group of shrimp was exposed to hypoxia for 6h followed by reoxygenation for 1h. Shrimp injected with long dsRNAs had lower cMnSOD transcripts in gills and hepatopancreas. In the cMnSOD silenced shrimp, superoxide dismutase (SOD) activity decreased in gills but not in hepatopancreas. Shrimp subjected to hypoxia had lower cMnSOD transcripts and SOD activity in gills and hepatopancreas; the production of superoxide anion (O2*-) by hemocytes was also lower in this group. Reoxygenation reverted the effect of hypoxia increasing the levels of cMnSOD transcripts, SOD activity and the production of O2*-. These results suggest that cMnSOD contributes significantly to the SOD activity in gills and hepatopancreas and indicate its importance in the redox system regulation for L. vannamei.

  6. Dynamic optical imaging of metabolic and NADPH oxidase-derived superoxide in live mouse brain using fluorescence lifetime unmixing.

    PubMed

    Hall, David J; Han, Sung-Ho; Chepetan, Andre; Inui, Edny G; Rogers, Mike; Dugan, Laura L

    2012-01-01

    Superoxide is the single-electron reduction product of molecular oxygen generated by mitochondria and the innate immune enzyme complex, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (Nox), and its isoforms. Initially identified as critical to the host defense against infection, superoxide has recently emerged as an important signaling molecule and as a proposed mediator of central nervous system injury in stroke, neurodegenerative conditions, and aging itself. Complete understanding of superoxide in central nervous system disease has been hampered by lack of noninvasive imaging techniques to evaluate this highly reactive, short-lived molecule in vivo. Here we describe a novel optical imaging technique to monitor superoxide real time in intact animals using a fluorescent probe compound and fluorescence lifetime contrast-based unmixing. Specificity for superoxide was confirmed using validated mouse models with enhanced or attenuated brain superoxide production. Application of fluorescence lifetime unmixing removed autofluorescence, further enhanced sensitivity and specificity of the technique, permitted visualization of physiologically relevant levels of superoxide, and allowed superoxide in specific brain regions (e.g., hippocampus) to be mapped. Lifetime contrast-based unmixing permitted disease model-specific and brain region-specific differences in superoxide levels to be observed, suggesting this approach may provide valuable information on the role of mitochondrial and Nox-derived superoxide in both normal function and pathologic conditions in the central nervous system.

  7. UV-irradiation provokes generation of superoxide on cell wall polygalacturonic acid.

    PubMed

    Pristov, Jelena Bogdanović; Jovanović, Sonja Veljović; Mitrović, Aleksandra; Spasojević, Ivan

    2013-08-01

    We examined the redox effects of UV irradiation on cell wall isolates from Pisum sativum leaves, and polygalacturonic and galacturonic acid, in the presence of hydrogen peroxide. For this purpose, electron paramagnetic resonance spectroscopy and two spin-traps (DEPMPO and BMPO), capable of differentiating between various free radicals, were applied. Systems were exposed to UV-B (maximum emission at 312 nm) and UV-A (352 nm) for 10 min (6 J m(-2) s(-1)). Cell wall isolates exposed to UV in the presence of hydrogen peroxide, produced hydroxyl radical, carbon dioxide radical and superoxide. The production of superoxide was observed for cell wall isolates, polygalacturonic acid (in the presence and in the absence of calcium) and galacturonic acid, and it was diminished upon superoxide dismutase supplementation. The production is at least partially based on the reaction of hydroxyl radicals with (poly)galacturonic acid having carbon dioxide radicals as a products. Acting as a strong reducing agent, carbon dioxide radical reacts with molecular oxygen to produce superoxide. The results presented here shed a new light on: (1) the redox-modulating role of cell wall; (2) the production of superoxide in the extracellular compartment; (3) the mechanisms involved in translating UV stress into molecular signaling and (4) some other UV-related phenomena in plants, such as CO(2) emission. PMID:23163764

  8. Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps.

    PubMed

    Bézière, Nicolas; Hardy, Micael; Poulhès, Florent; Karoui, Hakim; Tordo, Paul; Ouari, Olivier; Frapart, Yves-Michel; Rockenbauer, Antal; Boucher, Jean-Luc; Mansuy, Daniel; Peyrot, Fabienne

    2014-02-01

    Reactive oxygen species are by-products of aerobic metabolism involved in the onset and evolution of various pathological conditions. Among them, the superoxide radical is of special interest as the origin of several damaging species such as H2O2, hydroxyl radical, or peroxynitrite (ONOO(-)). Spin trapping coupled with ESR is a method of choice to characterize these species in chemical and biological systems and the metabolic stability of the spin adducts derived from reaction of superoxide and hydroxyl radicals with nitrones is the main limit to the in vivo application of the method. Recently, new cyclic nitrones bearing a triphenylphosphonium or permethylated β-cyclodextrin moiety have been synthesized and their spin adducts demonstrated increased stability in buffer. In this article, we studied the stability of the superoxide adducts of four new cyclic nitrones in the presence of liver subcellular fractions and biologically relevant reductants using an original setup combining a stopped-flow device and an ESR spectrometer. The kinetics of disappearance of the spin adducts were analyzed using an appropriate simulation program. Our results highlight the interest of the new spin trapping agents CD-DEPMPO and CD-DIPPMPO for specific detection of superoxide with high stability of the superoxide adducts in the presence of liver microsomes. PMID:24161442

  9. 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.

  10. Superoxide dismutase and catalase conjugated to polyethylene glycol increases endothelial enzyme activity and oxidant resistance

    SciTech Connect

    Beckman, J.S.; Minor, R.L. Jr.; White, C.W.; Repine, J.E.; Rosen, G.M.; Freeman, B.A.

    1988-05-15

    Covalent conjugation of superoxide dismutase and catalase with polyethylene glycol (PEG) increases the circulatory half-lives of these enzymes from <10 min to 40 h, reduced immunogenicity, and decreases sensitivity to proteolysis. Because PEG has surface active properties and can induce cell fusion, the authors hypothesized that PEG conjugation could enhance cell binding and association of normally membrane-impermeable enzymes. Incubation of cultured porcine aortic endothelial cells with /sup 125/I-PEG-catalase or /sup 125/I-PEG-superoxide dismutase produced a linear, concentration-dependent increase in cellular enzyme activity and radioactivity. Fluorescently labeled PEG-superoxide dismutase incubated with endothelial cells showed a vesicular localization. Mechanical injury to cell monolayers, which is known to stimulate endocytosis, further increased the uptake of fluorescent PEG-superoxide dismutase. Addition of PEG and PEG-conjugated enzymes perturbed the spin-label binding environment, indicative of producing an increase in plasma membrane fluidity. Thus, PEG conjugation to superoxide dismutase and catalase enhances cell association of these enzymes in a manner which increases cellular enzyme activities and provides prolonged protection from partially reduced oxygen species.

  11. Superoxide radicals scavenging and xanthine oxidase inhibitory activity of magnesium lithospermate B from Salvia miltiorrhiza.

    PubMed

    Liu, Xiaoyu; Chen, Ruohua; Shang, Yanjun; Jiao, Binghua; Huang, Caiguo

    2009-06-01

    In this study we investigated the superoxide radicals scavenging effect and xanthine oxidase inhibitory activity by magnesium lithospermate B, which was originally isolated from the roots of Salvia miltiorrhiza (also named Danshen or Dansham), an important herb in Oriental medicine. Superoxide radicals were generated both in beta-NADH/PMS system and xanthine/ xanthine oxidase system. Magnesium lithospermate B significantly inhibited the reduction of NBT induced by superoxide radicals with an IC(50) of 29.8 microg/mL and 4.06 microg/mL respectively in the two systems. Further study suggested that magnesium lithospermate B can directly inhibit xanthine oxidase and exhibits competitive inhibition. Magnesium lithospermate B was also found to have the hypouricemic activity in vivo against potassium oxonate-induced hyperuricaemia in mice. After oral administration of magnesium lithospermate B at doses of 10, 20 and 30 mg/kg, there was a significant decrease in the serum urate level when compared to the hyperuricemia control. In addition, magnesium lithospermate B significantly protected HL-60 cells from superoxide radicals-induced apoptosis in the xanthine/ xanthine oxidase reactions. This study provided evidence that magnesium lithospermate B exhibits direct superoxide radicals scavenging and xanthine oxidase inhibitory activity.

  12. Nitration and Inactivation of Manganese Superoxide Dismutase in Chronic Rejection of Human Renal Allografts

    NASA Astrophysics Data System (ADS)

    MacMillan-Crow, L. A.; Crow, John P.; Kerby, Jeffrey D.; Beckman, Joseph S.; Thompson, John A.

    1996-10-01

    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 μ M) 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.

  13. Superoxide radical scavenging ability of centrophenoxine and its salt dependence in vitro.

    PubMed

    Semsei, I; Zs-Nagy, I

    1985-01-01

    The superoxide radical scavenging ability of centrophenoxine (CPH) and its components (dimethylaminoethanol = DMAE, p-chlorophenoxyacetic acid = PCPA) was studied in vitro using the method of pyrogallol autoxidation, cytochrome c reduction and photoxidation of o-dianisidine in salt-free assay media and in the presence of increasing NaCl or KCl concentrations. The CPH proved to be a superoxide radical scavenger in all three systems used, however, the rate constant for this reaction was rather low (1.7 X 10(2) M-1 s-1). This scavenging ability decreased linearly with increasing ionic strength. DMAE and PCPA behaved in a somewhat contradictory manner. The former proved to be a weak superoxide radical generating compound being partially sensitive to the ionic strength. The latter showed either superoxide radical scavenging or generating effects in various assays depending on the actual salt concentrations of the media. On the basis of the results one has to assume that the superoxide radical scavenger ability of CPH may hardly be responsible for the in vivo effects of this compound, therefore, its OH. radical scavenger reactions the rate constant of which is about 10(9) M-1 s-1 may be of much greater importance.

  14. Endothelin-1 critically influences cardiac function via superoxide-MMP9 cascade

    PubMed Central

    Hathaway, Catherine K.; Grant, Ruriko; Hagaman, John R.; Hiller, Sylvia; Li, Feng; Xu, Longquan; Chang, Albert S.; Madden, Victoria J.; Bagnell, C. Robert; Rojas, Mauricio; Kim, Hyung-Suk; Wu, Bingruo; Zhou, Bin; Smithies, Oliver; Kakoki, Masao

    2015-01-01

    We have generated low-expressing and high-expressing endothelin-1 genes (L and H) and have bred mice with four levels of expression: L/L, ∼20%; L/+, ∼65%; +/+ (wild type), 100%; and H/+, ∼350%. The hypomorphic L allele can be spatiotemporally switched to the hypermorphic H allele by Cre-loxP recombination. Young adult L/L and L/+ mice have dilated cardiomyopathy, hypertension, and increased plasma volumes, together with increased ventricular superoxide levels, increased matrix metalloproteinase 9 (Mmp9) expression, and reduced ventricular stiffness. H/+ mice have decreased plasma volumes and significantly heavy stiff hearts. Global or cardiomyocyte-specific switching expression from L to H normalized the abnormalities already present in young adult L/L mice. An epithelial sodium channel antagonist normalized plasma volume and blood pressure, but only partially corrected the cardiomyopathy. A superoxide dismutase mimetic made superoxide levels subnormal, reduced Mmp9 overexpression, and substantially improved cardiac function. Genetic absence of Mmp9 also improved cardiac function, but increased superoxide remained. We conclude that endothelin-1 is critical for maintaining normal contractile function, for controlling superoxide and Mmp9 levels, and for ensuring that the myocardium has sufficient collagen to prevent overstretching. Even a modest (∼35%) decrease in endothelin-1 gene (Edn1) expression is sufficient to cause cardiac dysfunction. PMID:25848038

  15. 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.

  16. 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.

  17. Superoxide Dismutase 1 Loss Disturbs Intracellular Redox Signaling, Resulting in Global Age-Related Pathological Changes

    PubMed Central

    2014-01-01

    Aging is characterized by increased oxidative stress, chronic inflammation, and organ dysfunction, which occur in a progressive and irreversible manner. Superoxide dismutase (SOD) serves as a major antioxidant and neutralizes superoxide radicals throughout the body. In vivo studies have demonstrated that copper/zinc superoxide dismutase-deficient (Sod1−/−) mice show various aging-like pathologies, accompanied by augmentation of oxidative damage in organs. We found that antioxidant treatment significantly attenuated the age-related tissue changes and oxidative damage-associated p53 upregulation in Sod1−/− mice. This review will focus on various age-related pathologies caused by the loss of Sod1 and will discuss the molecular mechanisms underlying the pathogenesis in Sod1−/− mice. PMID:25276767

  18. Determination of metal content in superoxide dismutase enzymes by capillary electrophoresis†.

    PubMed

    Kazarjan, Jana; Vaher, Merike; Hunter, Thérèse; Kulp, Maria; Hunter, Gary James; Bonetta, Rosalin; Farrugia, Diane; Kaljurand, Mihkel

    2015-03-01

    Superoxide dismutases are antioxidant scavenger enzymes that contain a metal cofactor (copper, zinc, iron, and manganese) in their active site. Metal content measurement is one of the essential steps to characterize enzyme biological activity. We have developed a capillary electrophoretic protocol for the determination of the metal content in superoxide dismutase enzymes. The background electrolyte containing 10 mM pyridine-2,6-dicarboxylic acid and 1 mM 1-methyl-3-tetradecylimidazolium chloride at pH 3.8 was optimized for on-column complexation of the above-mentioned metals. The minimum detectable levels of metals ranged from 0.3 to 1.2 μg/mL. The reliability of the method was checked by parallel quantitative determination of the metal content in superoxide dismutase enzymes by graphite furnace or flame atomic absorption spectrophotometry methods.

  19. Use of superoxide as an electron shuttle for iron acquisition by the marine cyanobacterium Lyngbya majuscula.

    PubMed

    Rose, Andrew L; Salmon, Tim P; Lukondeh, Tredwell; Neilan, Brett A; Waite, T David

    2005-05-15

    Reduction of iron from the ferric state to the ferrous state is one strategy employed by microorganisms in nearneutral environments to increase its biological availability. In recent years, the existence of mobile reducing agents produced bymicroorganismsto promote iron reduction, known as electron shuttles, has been demonstrated. Production of electron shuttles has been shown for several organisms, employing a variety of mostly organic molecules as the electron carrier. Here we show that the coastal cyanobacterium Lyngbya majuscula produces iron-reducing superoxide radicals (02*-) and that this facilitates increased iron uptake. We suggest that superoxide is a useful electron shuttle because it reacts rapidly and almost indiscriminately with Fe(lll)-organic complexes and its precursor, dissolved oxygen, is ubiquitous in the photic zone. We further suggest that, for these reasons, the generation of superoxide by marine oxygenic photosynthetic microorganisms and its use in facilitating iron uptake may be a reasonably widespread process.

  20. Superoxide dismutase 1 acts as a nuclear transcription factor to regulate oxidative stress resistance

    PubMed Central

    Tsang, Chi Kwan; Liu, Yuan; Thomas, Janice; Zhang, Yanjie; Zheng, X. F. Steven

    2015-01-01

    Summary Superoxide dismutase 1 (Sod1) has been known for nearly half a century for catalysis of superoxide to hydrogen peroxide. Here we report a new Sod1 function in oxidative signaling: in response to elevated endogenous and exogenous reactive oxygen species (ROS), Sod1 rapidly relocates into the nucleus, which is important for maintaining genomic stability. Interestingly, H2O2 is sufficient to promote Sod1 nuclear localization, indicating that it is responding to general ROS rather than Sod1 substrate superoxide. ROS signaling is mediated by Mec1/ATM and its effector Dun1/Cds1 kinase, through Dun1 interaction with Sod1 and regulation of Sod1 by phosphorylation at S60, 99. In the nucleus, Sod1 binds to the promoters and regulates the expression of oxidative resistance and repair genes. Altogether, our study unravels an unorthodox function of Sod1 as a transcription factor and elucidates the regulatory mechanism for its localization. PMID:24647101

  1. Superoxide metabolism is correlated to the post-anoxic injury of soybean (Glycine max) roots

    SciTech Connect

    Bolles, C.S.; Van Toai, T.T. )

    1990-05-01

    Post-anoxic injury of root tips of soybean seedlings is more severe following a very short (1 hour) period of anoxia than a longer (3-5 hour) period. Anaerobic incubation of root tips in the presence of 100 mM ascorbate, an antioxidant and free-radical-scavenging compound, alleviates the detrimental post-anoxia effects of a very short anoxic treatment. Extracts of root tips which have been treated anoxically for 1 hour have an elevated capacity to produce superoxide anions when subsequently exposed to air, than extracts from seedlings treated anoxically for longer time. Changes in superoxide dismutase (SOD) enzyme activity and SOD-specific RNA sequences will be presented. The results support that post-anoxic injury occurs in soybean roots and that SOD plays a role in the detoxification of superoxide anions.

  2. Endogenous antioxidant defense induction by melon superoxide dismutase reduces cardiac hypertrophy in spontaneously hypertensive rats.

    PubMed

    Carillon, Julie; Rugale, Caroline; Rouanet, Jean-Max; Cristol, Jean-Paul; Lacan, Dominique; Jover, Bernard

    2014-08-01

    We assessed the influence of SODB, a melon superoxide dismutase (SOD), on left ventricular (LV) hypertrophy in SHR. SODB (4 or 40U SOD) was given orally for 4 or 28 days to SHR. For each treatment period, LV weight index (LVWI) and cardiomyocytes size were measured. SOD, glutathione peroxidase (GPx) and catalase expressions, and LV production and presence of superoxide anion were determined. Pro-inflammatory markers were also measured. SODB reduced LVWI and cardiomyocytes size after 4 or 28 days. Cardiac SOD and GPx increased by 30-40% with SODB. The presence but not production of superoxide anion was significantly reduced by SODB. No effect of SODB was detected on inflammatory status in any group. The beneficial effect of SODB on cardiac hypertrophy seems to be related to the stimulation of endogenous antioxidant defense, suggesting that SODB may be of interest as a dietary supplementation during conventional antihypertensive therapy.

  3. Effect of pH on the conversion of superoxide to hydroxyl free radicals

    SciTech Connect

    Baker, M.S.; Gebicki, J.M.

    1984-10-01

    The conversion of superoxide (O-.2) to the hydroxyl (HO.) free radical by superoxide-driven Fenton reactions was measured by the formation of hydroxylated derivatives from benzoate. Among a range of catalysts required for the conversion, the Fe3+EDTA complex was the most effective. The effect of superoxide dismutase and catalase indicated that O-.2 and H2O2 were essential reactants, while the formation of authentic HO. was confirmed by the inhibiting capacities of formate, t-butanol, and mannitol. The conversion of O-.2 to HO. was tested over a broad pH range, and was found to be highest at pH 4.8 whether Fe3+EDTA or free Fe3+ were used as the catalysts. When Fe3+EDTA was used at the optimum pH, every HO. produced required 3.7 O-.2 radicals, close to the theoretical limit of one HO. from every three O-.2 radicals generated.

  4. Reactions of Co(III)–Nitrosyl Complexes with Superoxide and Their Mechanistic Insights

    PubMed Central

    Kumar, Pankaj; Lee, Yong-Min; Park, Young Jun; Siegler, Maxime A.; Karlin, Kenneth D.; Nam, Wonwoo

    2015-01-01

    New CoIII-nitrosyl complexes bearing N-tetramethylated cyclam (TMC) ligands, [(12-TMC)CoIII(NO)]2+ (1) and [(13-TMC)CoIII(NO)]2+ (2), were synthesized via [(TMC)CoII(CH3CN)]2+ plus NO(g) reactions. Spectroscopic and structural characterization shows that these compounds bind the nitrosyl moiety in a bent end-on fashion. The CoIII-nitrosyl complexes, (1) and (2), reacted with KO2/2.2.2-Cryptand and produced [(12-TMC)CoII(NO2)]+ (3) and [(13-TMC)CoII(NO2)]+ (4), respectively; these possess O,O’-chelated nitrito ligands. Mechanistic studies using 18O-labeled superoxide (18O2•−) demonstrate that one oxygen atom in the nitrito ligand derives from superoxide and dioxygen produced comes from the other superoxide oxygen atom. Evidence supporting the formation of a Co-peroxynitrite intermediate is also presented. PMID:25793706

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

    PubMed

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

    2010-06-01

    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

  6. Elevated peripheral blood mononuclear cell-derived superoxide production in healthy young black men.

    PubMed

    Deo, Shekhar H; Holwerda, Seth W; Keller, David M; Fadel, Paul J

    2015-03-01

    Several studies have demonstrated that blacks exhibit elevations in systemic oxidative stress. However, the source(s) and mechanism(s) contributing to the elevation in oxidative stress remain unclear. Given that peripheral blood mononuclear cells (PBMCs) can be a major source of NADPH oxidase-derived superoxide production, we tested the hypothesis that young black men demonstrate greater superoxide production and NADPH oxidase expression in PBMCs compared with whites. PBMCs were freshly isolated from whole blood in young normotensive black (n = 18) and white (n = 16) men. Intracellular superoxide production in PBMCs was measured using dihydroethidium fluorescence, protein expression of NADPH oxidase subunits, gp91(phox) (membranous) and p47(phox) (cytosolic) in PBMCs were assessed using Western blot analysis, and plasma protein carbonyls were measured as a marker of systemic oxidative stress. Black men showed elevated intracellular superoxide production (4.3 ± 0.5 vs. 2.0 ± 0.6 relative fluorescence units; black men vs. white men, P < 0.05), increased protein expression for gp91(phox) and p47(phox) (e.g., p47(phox): 1.1 ± 0.2, black men vs. 0.4 ± 0.1, white men, P < 0.05) in PBMCs and higher circulating protein carbonyl levels (22 ± 4 vs. 14 ± 2 nmol/ml; black men vs. white men, P < 0.05). Interestingly, a positive family history of hypertension in black men did not further enhance PBMC-derived intracellular superoxide production or NADPH oxidase subunit protein expression. These findings indicate that black men exhibit greater resting PBMC-derived superoxide production and an upregulation of the NADPH oxidase pathway with a possible contribution to increases in systemic oxidative stress.

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

    PubMed

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

    2000-09-15

    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.

  8. Desferrioxamine (Desferal) and superoxide free radicals. Formation of an enzyme-damaging nitroxide.

    PubMed Central

    Davies, M J; Donkor, R; Dunster, C A; Gee, C A; Jonas, S; Willson, R L

    1987-01-01

    In neutral solutions, desferrioxamine (Desferal) can react with the superoxide free radical, O2.- (possibly through its protonated form HO2.), to form a relatively stable nitroxide free radical, which can have a half-life of approx. 10 min at room temperature. The formation of the radical can be largely prevented by the presence of superoxide dismutase. The radical reacts rapidly with cysteine, methionine, glutathione, vitamin C and a water-soluble derivative of vitamin E. It also reacts rapidly with alcohol dehydrogenase, causing a loss of enzyme activity. The implications of these findings for mechanistic free-radical biochemistry and iron-chelation therapy could be considerable. PMID:2825650

  9. Serine 1179 Phosphorylation of Endothelial Nitric Oxide Synthase Increases Superoxide Generation and Alters Cofactor Regulation.

    PubMed

    Peng, Hu; Zhuang, Yugang; Harbeck, Mark C; He, Donghong; Xie, Lishi; Chen, Weiguo

    2015-01-01

    Endothelial nitric oxide synthase (eNOS) is responsible for maintaining systemic blood pressure, vascular remodeling and angiogenesis. In addition to producing NO, eNOS can also generate superoxide (O2-.) in the absence of the cofactor tetrahydrobiopterin (BH4). Previous studies have shown that bovine eNOS serine 1179 (Serine 1177/human) phosphorylation critically modulates NO synthesis. However, the effect of serine 1179 phosphorylation on eNOS superoxide generation is unknown. Here, we used the phosphomimetic form of eNOS (S1179D) to determine the effect of S1179 phosphorylation on superoxide generating activity, and its sensitivity to regulation by BH4, Ca2+, and calmodulin (CAM). S1179D eNOS exhibited significantly increased superoxide generating activity and NADPH consumption compared to wild-type eNOS (WT eNOS). The superoxide generating activities of S1179D eNOS and WT eNOS did not differ significantly in their sensitivity to regulation by either Ca2+ or CaM. The sensitivity of the superoxide generating activity of S1179D eNOS to inhibition by BH4 was significantly reduced compared to WT eNOS. In eNOS-overexpressing 293 cells, BH4 depletion with 10mM DAHP for 48 hours followed by 50ng/ml VEGF for 30 min to phosphorylate eNOS S1179 increased ROS accumulation compared to DAHP-only treated cells. Meanwhile, MTT assay indicated that overexpression of eNOS in HEK293 cells decreased cellular viability compared to control cells at BH4 depletion condition (P<0.01). VEGF-mediated Serine 1179 phosphorylation further decreased the cellular viability in eNOS-overexpressing 293 cells (P<0.01). Our data demonstrate that eNOS serine 1179 phosphorylation, in addition to enhancing NO production, also profoundly affects superoxide generation: S1179 phosphorylation increases superoxide production while decreasing sensitivity to the inhibitory effect of BH4 on this activity. PMID:26560496

  10. Construction of a Fusion Enzyme Exhibiting Superoxide Dismutase and Peroxidase Activity.

    PubMed

    Sharapov, M G; Novoselov, V I; Ravin, V K

    2016-04-01

    A chimeric gene construct encoding human peroxiredoxin 6 and Mn-superoxide dismutase from Escherichia coli was developed. Conditions for expression of the fusion protein in E. coli cell were optimized. Fusing of the enzymes into a single polypeptide chain with peroxiredoxin 6 at the N-terminus (PSH) did not affect their activities. On the contrary, the chimeric protein with reverse order of enzymes (SPH) was not obtained in a water-soluble active form. The active chimeric protein (PSH) exhibiting both peroxidase and superoxide dismutase activities was prepared and its physicochemical properties were characterized. PMID:27293100

  11. Titanium Dioxide Nanoparticles Increase Superoxide Anion Production by Acting on NADPH Oxidase

    PubMed Central

    Trepout, Sylvain; Wien, Frank; Marco, Sergio

    2015-01-01

    Titanium dioxide (TiO2) anatase nanoparticles (NPs) are metal oxide NPs commercialized for several uses of everyday life. However their toxicity has been poorly investigated. Cellular internalization of NPs has been shown to activate macrophages and neutrophils that contribute to superoxide anion production by the NADPH oxidase complex. Transmission electron micrososcopy images showed that the membrane fractions were close to the NPs while fluorescence indicated an interaction between NPs and cytosolic proteins. Using a cell-free system, we have investigated the influence of TiO2 NPs on the behavior of the NADPH oxidase. In the absence of the classical activator molecules of the enzyme (arachidonic acid) but in the presence of TiO2 NPs, no production of superoxide ions could be detected indicating that TiO2 NPs were unable to activate by themselves the complex. However once the NADPH oxidase was activated (i.e., by arachidonic acid), the rate of superoxide anion production went up to 140% of its value without NPs, this effect being dependent on their concentration. In the presence of TiO2 nanoparticles, the NADPH oxidase produces more superoxide ions, hence induces higher oxidative stress. This hyper-activation and the subsequent increase in ROS production by TiO2 NPs could participate to the oxidative stress development. PMID:26714308

  12. NADH Induces the Generation of Superoxide Radicals in Leaf Peroxisomes 1

    PubMed Central

    del Río, Luis A.; Fernández, Víctor M.; Rupérez, Francisco L.; Sandalio, Luisa M.; Palma, José M.

    1989-01-01

    In peroxisomes isolated from pea leaves (Pisum sativum L.) the production of superoxide free radicals (O2−) by xanthine and NADH was investigated. In peroxisomal membranes, 100 micromolar NADH induced the production of O2− radicals. In the soluble fractions of peroxisomes, no generation of O2− 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 against xanthine oxidase. The generation of superoxide radicals in leaf peroxisomes together with the recently described production of these oxygen radicals in glyoxysomes (LM Sandalio, VM Fernández, FL Rupérez, LA del Río [1988] Plant Physiol 87: 1-4) suggests that O2− generation could be a common metabolic property of peroxisomes and further supports the existence of active oxygen-related rôles for peroxisomes in cellular metabolism. PMID:16666612

  13. Curcumin Rescues Diabetic Renal Fibrosis by Targeting Superoxide-Mediated Wnt Signaling Pathways.

    PubMed

    Ho, Cheng; Hsu, Yung-Chien; Lei, Chen-Chou; Mau, Shu-Ching; Shih, Ya-Hsueh; Lin, Chun-Liang

    2016-03-01

    The purposes of this study were to investigate whether curcumin can weaken diabetic nephropathy by modulating both oxidative stress and renal injury from Wnt signaling mediation. Wnt5a/β-catenin depression and induction of superoxide synthesis are associated with high glucose (HG) induced transforming growth factor (TGF)-β1 and fibronectin expression in mesangial cells. Curcumin resumes HG depression of Wnt/β-catenin signaling and alleviates HG induction of superoxide, TGF-β1 and fibronectin expression in renal mesangial cell. Exogenous curcumin alleviated urinary total proteinuria and serum superoxide level in diabetic rats. Based on laser-captured microdissection for quantitative real-time polymerase chain reaction, it was found that diabetes significantly increased TGF-β1 and fibronectin expression in line with depressed Wnt5a expression. Curcumin treatment reduced the TGF-β1 and fibronectin activation and the inhibiting effect of diabetes on Wnt5a/β-catenin expression in renal glomeruli. Immunohistochemistry showed that curcumin treatment significantly reduced 8-hydroxy-2'-deoxyguanosine, TGF-β1 and fibronectin, and was in line with the restoration of the suppressed Wnt5a expression immunoreactivities in glomeruli of diabetic rats. Curcumin alleviated extracellular matrix accumulation in diabetic nephropathy by not only preventing the diabetes-mediated superoxide synthesis but also resuming downregulation of Wnt/β-catenin signaling. These findings suggest that regulation of Wnt activity by curcumin is a feasible alternative strategy to rescue diabetic renal injury.

  14. Inhibition of the Ca sup 2+ -ATPase of vascular smooth muscle sarcoplasmic reticulum by superoxide radicals

    SciTech Connect

    Suzuki, Yuichiro; Ford, G.D. )

    1991-03-15

    The effect of oxygen free radicals generated by hypoxanthine plus xanthine oxidase on the Ca{sup 2+}-ATPase of sarcoplasmic reticulum from bovine aortic smooth muscle were studied. Exogenous hypoxanthine plus xanthine oxidase produced an hypoxanthine concentration dependent inhibition of the Ca{sup 2+}-ATPase. The inhibition could be completely blocked by superoxide dismutase but not by either mannitol or deferoxamine. Direct addition of reagent hydrogen peroxide in the {mu}M range did not cause significant inhibition. These results suggest that superoxide is the primary damaging species. Additionally, 1.16 {plus minus} 0.17 mU/g wet wt of xanthine oxidase activity were detected in the post-nuclear supernatant of bovine aortic smooth muscle, suggesting the existence of a possible intracellular source of superoxide. This value was calculated to be approximately 5 mU/ml by using a usual value of vascular smooth muscle cellular volume. Thus the level of endogenous xanthine oxidase resident in vascular smooth muscle is comparable with the level of exogenous xanthine oxidase used in the present study. These findings suggest a potential role of xanthine oxidase-generated superoxide in free radical injury to vascular smooth muscle.

  15. Titanium Dioxide Nanoparticles Increase Superoxide Anion Production by Acting on NADPH Oxidase.

    PubMed

    Masoud, Rawand; Bizouarn, Tania; Trepout, Sylvain; Wien, Frank; Baciou, Laura; Marco, Sergio; Houée Levin, Chantal

    2015-01-01

    Titanium dioxide (TiO2) anatase nanoparticles (NPs) are metal oxide NPs commercialized for several uses of everyday life. However their toxicity has been poorly investigated. Cellular internalization of NPs has been shown to activate macrophages and neutrophils that contribute to superoxide anion production by the NADPH oxidase complex. Transmission electron micrososcopy images showed that the membrane fractions were close to the NPs while fluorescence indicated an interaction between NPs and cytosolic proteins. Using a cell-free system, we have investigated the influence of TiO2 NPs on the behavior of the NADPH oxidase. In the absence of the classical activator molecules of the enzyme (arachidonic acid) but in the presence of TiO2 NPs, no production of superoxide ions could be detected indicating that TiO2 NPs were unable to activate by themselves the complex. However once the NADPH oxidase was activated (i.e., by arachidonic acid), the rate of superoxide anion production went up to 140% of its value without NPs, this effect being dependent on their concentration. In the presence of TiO2 nanoparticles, the NADPH oxidase produces more superoxide ions, hence induces higher oxidative stress. This hyper-activation and the subsequent increase in ROS production by TiO2 NPs could participate to the oxidative stress development. PMID:26714308

  16. Glucose-6-phosphate dehydrogenase-derived NADPH fuels superoxide production in the failing heart

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the failing heart, NADPH oxidase and uncoupled NO synthase utilize cytosolic NADPH to form superoxide. NADPH is supplied principally by the pentose phosphate pathway, whose rate-limiting enzyme is glucose 6-phosphate dehydrogenase (G6PD). Therefore, we hypothesized that cardiac G6PD activation dr...

  17. Impact of hyperpigmentation on superoxide flux and melanoma cell metabolism at mitochondrial complex II.

    PubMed

    Boulton, Sarah Jayne; Birch-Machin, Mark A

    2015-01-01

    Melanogenesis is a highly conserved process of cytophotoprotection from UV radiation present in many species. Although both mitochondrial function and UV radiation insults are well-documented promoters of increased cellular stress, their individual molecular relationships with skin pigmentation have not been clearly resolved. This study provides evidence for a direct relationship between cellular melanin content, superoxide flux, and mitochondrial function at complex II. Direct and significant correlation between increased pigmentation and complex II turnover was observed in genetically different melanoma cell lines of varied basal pigmentation states (P < 0.01). The same trend was also observed when comparing genetically identical cell cultures with increasing levels of induced pigmentation (P < 0.005). The observation of increased steady-state levels of the catalytic complex II succinate dehydrogenase subunit A alongside hyperpigmentation suggested coregulation of activity and pigment production (P < 0.01). The study also presents novel evidence for a relationship between hyperpigmentation and increased superoxide-generating capacity at complex II. By amperometrically monitoring superoxide flux from differently pigmented FM55 melanocytes and their isolated mitochondria, a dynamic and responsive relationship between pigmentation, complex II function, and intracellular superoxide generation was observed (P < 0.005). The data support hyperpigmentation as a protective antioxidant mechanism in response to complex II-mediated reactive oxygen species generation. PMID:25351989

  18. Mitochondrial superoxide in osteocytes perturbs canalicular networks in the setting of age-related osteoporosis.

    PubMed

    Kobayashi, Keiji; Nojiri, Hidetoshi; Saita, Yoshitomo; Morikawa, Daichi; Ozawa, Yusuke; Watanabe, Kenji; Koike, Masato; Asou, Yoshinori; Shirasawa, Takuji; Yokote, Koutaro; Kaneko, Kazuo; Shimizu, Takahiko

    2015-03-16

    Osteocytes are major bone cells that play a crucial role in maintaining the quality of and healing damage to bone tissue. The number of living osteocytes and canalicular networks declines in an age-dependent manner. However, the pathological effects of mitochondrial redox imbalances on osteocytes and bone metabolism have not been fully elucidated. We generated mice lacking mitochondrial superoxide dismutase 2 (Sod2) in osteocytes. Like an aged bone, Sod2 depletion in the osteocytes positively enhanced the production of cellular superoxide in vivo. A bone morphological analysis demonstrated that the Sod2-deficient femurs showed remarkable bone loss in an age-dependent manner. Interestingly, Sod2 loss induced markedly disorganized osteocytic canalicular networks and decreased the number of live osteocytes. Furthermore, Sod2 deficiency significantly suppressed bone formation and increased bone resorption concomitant with the upregulation of sclerostin and receptor activator of NF-κB ligand (RANKL). In vitro experiments also revealed that treatment with paraquat, a superoxide inducer in mitochondria, promoted the RANKL expression via, in part, ERK phosphorylation. These findings demonstrate that the mitochondrial superoxide induced in osteocytes by Sod2 ablation causes age-related bone loss due to the impairment of canalicular networks and bone metabolism via the deregulation of the sclerostin and RANKL expression.

  19. Mitochondria-targeted spin traps: synthesis, superoxide spin trapping, and mitochondrial uptake.

    PubMed

    Hardy, Micael; Poulhés, Florent; Rizzato, Egon; Rockenbauer, Antal; Banaszak, Karol; Karoui, Hakim; Lopez, Marcos; Zielonka, Jacek; Vasquez-Vivar, Jeannette; Sethumadhavan, Savitha; Kalyanaraman, Balaraman; Tordo, Paul; Ouari, Olivier

    2014-07-21

    Development of reliable methods and site-specific detection of free radicals is an active area of research. Here, we describe the synthesis and radical-trapping properties of new derivatives of DEPMPO and DIPPMPO, bearing a mitochondria-targeting triphenylphosphonium cationic moiety or guanidinium cationic group. All of the spin traps prepared have been observed to efficiently trap superoxide radical anions in a cell-free system. The superoxide spin adducts exhibited similar spectral properties, indicating no significant differences in the geometry of the cyclic nitroxide moieties of the spin adducts. The superoxide adduct stability was measured and observed to be highest (t1/2 = 73 min) for DIPPMPO nitrone linked to triphenylphosphonium moiety via a short carbon chain (Mito-DIPPMPO). The experimental results and DFT quantum chemical calculations indicate that the cationic property of the triphenylphosphonium group may be responsible for increased superoxide trapping efficiency and adduct stability of Mito-DIPPMPO, as compared to the DIPPMPO spin trap. The studies of uptake of the synthesized traps into isolated mitochondria indicated the importance of both cationic and lipophilic properties, with the DEPMPO nitrone linked to the triphenylphosphonium moiety via a long carbon chain (Mito10-DEPMPO) exhibiting the highest mitochondrial uptake. We conclude that, of the synthesized traps, Mito-DIPPMPO and Mito10-DEPMPO are the best candidates for potential mitochondria-specific spin traps for use in biologically relevant systems. PMID:24890552

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  1. Liposome-encapsulated superoxide dismutase mimetic: theranostic potential of an MR detectable and neuroprotective agent

    PubMed Central

    Shazeeb, Mohammed Salman; Feula, Giancarlo; Bogdanov, Alexei

    2014-01-01

    Endogenous manganese based superoxide dismutase (Mn-SOD) provides the primary defense against excess production of potentially toxic superoxide anion (O2−). M40401 is a synthetic enzyme mimetic that has a catalytic activity rate exceeding that of the native SOD enzymes. The presence of a paramagnetic Mn(II) cation in M40401 suggests that the delivery and spatial distribution of this enzyme mimetic in vivo may be directly detectible using magnetic resonance imaging (MRI); however, the cardiotoxicity of Mn(II) severely limits the use of free M40401 in living systems. To deliver M40401 in vivo in amounts sufficient for MRI detection and to limit potential cardiotoxicity, we encapsulated M40401 into 170 nm liposomes composed of phosphatidylcholine and PEGylated phosphatidylethanolamine to achieve extended circulation in the bloodstream. The obtained liposomes efficiently catalyzed superoxide dismutation in vitro. Using 3 T MRI we investigated the biokinetics of liposome-encapsulated M40401 in mice and found that in addition to catalyzing superoxide dismutation in vitro, M40401 caused differential and region-specific enhancement of mouse brain after the systemic administration. Thus, liposome encapsulated M40401 is an ideal candidate for development as a theranostic compound useful for simultaneous MRI-mediated tracking of delivery as well as for neuroprotective treatment of ischemic brain. PMID:24700749

  2. 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…

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

    SciTech Connect

    del Rio, L.A.; Sandalio, L.M.; Palma, J.M. ); Fernandez, V.M.; Ruperez, F.L. )

    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 against 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.

  4. Non-heme iron hydroperoxo species in superoxide reductase as a catalyst for oxidation reactions.

    PubMed

    Rat, S; Ménage, S; Thomas, F; Nivière, V

    2014-11-25

    The non-heme high-spin ferric iron hydroperoxo species formed in superoxide reductase catalyzes oxidative aldehyde deformylation through its nucleophilic character. This species also acts as an electrophile to catalyze oxygen atom transfer in sulfoxidation reactions, highlighting the oxidation potential of non-heme iron hydroperoxo species.

  5. Induction of peroxidases and superoxide dismutases in transformed embryogenic calli of alfalfa (Medicago sativa L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Activities of peroxidase (POD) and superoxide dismutase (SOD) enzymes were analyzed in non-regenerative transformed embryogenic lines of alfalfa (Medicago sativa L.) carrying wound-inducible oryzacystatin I (OC-I), wound-inducible oryzacystatin I antisense (OC-Ias) or hygromycin phosphotransferase (...

  6. Periplasmic superoxide dismutase SodCI of Salmonella binds peptidoglycan to remain tethered within the periplasm

    PubMed Central

    Kim, Byoungkwan; Slauch, James M.

    2015-01-01

    Summary Salmonellae survive and propagate in macrophages to cause serious systemic disease. Periplasmic superoxide dismutase plays a critical role in this survival by combating phagocytic superoxide. Salmonella Typhimurium strain 14028 produces two periplasmic superoxide dismutases, SodCI and SodCII. Although both proteins are produced during infection, only SodCI is functional in the macrophage phagosome. We have previously shown that SodCI, relative to SodCII, is both protease resistant and tethered within the periplasm, and that either of these properties is sufficient to allow a SodC to protect against phagocytic superoxide. Tethering is defined as remaining cell-associated after osmotic shock or treatment with cationic antimicrobial peptides. Here we show that SodCI non-covalently binds peptidoglycan. SodCI binds to Salmonella and Bacillus peptidoglycan, but not peptidoglycan from Staphylococcus. Moreover, binding can be inhibited by a diaminopimelic acid containing tripeptide, but not a lysine containing tripeptide, showing that the protein recognizes the peptide portion of the peptidoglycan. Replacing nine amino acids in SodCII with the corresponding residues from SodCI confers tethering, partially delineating an apparently novel peptidoglycan binding domain. These changes in sequence increase the affinity of SodCII for peptidoglycan fragments to match that of SodCI, and allow the now tethered SodCII to function during infection. PMID:25998832

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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....

  8. Expression of Pyrococcus furiosus Superoxide Reductase in Arabidopsis Enhances Heat Tolerance1[C][W][OA

    PubMed Central

    Im, Yang Ju; Ji, Mikyoung; Lee, Alice; Killens, Rushyannah; Grunden, Amy M.; Boss, Wendy F.

    2009-01-01

    Plants produce reactive oxygen species (ROS) in response to environmental stresses sending signaling cues, which, if uncontrolled, result in cell death. Like other aerobic organisms, plants have ROS-scavenging enzymes, such as superoxide dismutase (SOD), which removes superoxide anion radical (O2−) and prevents the production and buildup of toxic free radicals. However, increasing the expression of cytosolic SODs is complex, and increasing their production in vivo has proven to be challenging. To avoid problems with endogenous regulation of gene expression, we expressed a gene from the archaeal hyperthermophile Pyrococcus furiosus that reduces O2−. P. furiosus uses superoxide reductase (SOR) rather than SOD to remove superoxide. SOR is a thermostable enzyme that reduces O2− in a one-electron reduction without producing oxygen. We show that P. furiosus SOR can be produced as a functional enzyme in planta and that plants producing SOR have enhanced tolerance to heat, light, and chemically induced ROS. Stress tolerance in the SOR-producing plants correlates positively with a delayed increase in ROS-sensitive transcripts and a decrease in ascorbate peroxidase activity. The SOR plants provide a good model system to study the impact of cytosolic ROS on downstream signaling in plant growth and development. Furthermore, this work demonstrates that this synthetic approach for reducing cytosolic ROS holds promise as a means for improving stress tolerance in crop plants. PMID:19684226

  9. 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...

  10. The role of superoxide in xanthine oxidase-induced autooxidation of linoleic acid.

    PubMed

    Thomas, M J; Mehl, K S; Pryor, W A

    1982-07-25

    The effect of hydroxyperoxyoctadecadienoic acid, e.g. 13-hydroperoxy-cis,9,trans-11-octadecadienoic acid, on the autooxidation of linoleic acid induced by superoxide radical was examined in a system containing xanthine oxidase, acetaldehyde, and diethylenetriaminepentaacetic acid dissolved in an aqueous phosphate buffer containing 10% ethanol. The superoxide radical is required for autooxidation, as shown by essentially complete inhibition on the addition of superoxide dismutase. Pure linoleic acid was not readily oxidized, but the addition of lipid hydroperoxide markedly stimulated the autooxidation. Addition of 2.8 microM FeCl3 did not produce an increase in the rate of xanthine oxidase-induced autooxidation. Spontaneous autooxidation, a process slower than xanthine oxidase-induced autooxidation, was detectable on the time scale of these observations but was slower than the xanthine oxidase-induced autooxidation. Initiation of linoleic acid autooxidation is postulated to result from a reaction between superoxide and lipid hydroperoxide. The nature of this reaction is uncertain, but it does not appear to depend on iron catalysis. PMID:6282880

  11. A mitochondrion targeting fluorescent probe for imaging of intracellular superoxide radicals.

    PubMed

    Si, Fang; Liu, Yang; Yan, Kelu; Zhong, Wenwan

    2015-05-01

    An amine-reactive fluorogenic molecule specifically turned on by superoxide radicals (O2˙(-)) was synthesized and coupled to a mitochondrial (MT) targeting peptide. The obtained probe showed superior uptake and MT targeting capabilities; and successfully detected the change in O2˙(-) levels in cells treated with chemical stimuli or single-walled carbon nanotubes.

  12. 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...

  13. Molecular cloning and biochemical characterization of iron superoxide dismutase from the rodent malaria parasite Plasmodium vinckei.

    PubMed

    Prakash, Kirtika; Goyal, Manish; Soni, Awakash; Siddiqui, Arif Jamal; Bhardwaj, Jyoti; Puri, Sunil K

    2014-12-01

    Plasmodium parasite utilizes superoxide dismutase family proteins to limit the toxicity of reactive oxygen species, such as produced through hemoglobin degradation. These proteins play an important role in parasite survival during intra-erythrocytic phase. We have identified, and biochemically characterized a putative iron dependent superoxide dismutase from rodent malaria parasite Plasmodium vinckei (PvSOD1). The recombinant PvSOD1 protein was purified to homogeneity through a combination of affinity and gel filtration chromatography. Crosslinking, Native-PAGE and FPLC gel filtration analyses documented that PvSOD1 exists as a dimer in solution, a common feature shared by other Fe-SODs. PvSOD1 is cytosolic in localization and its expression is comparatively higher during trophozoite as compared to that of ring and schizont stages. Enzymatic activity of recombinant PvSOD1 was validated using conventional zymogram analyses and xanthine-xanthine oxidase system. Under optimal conditions, PvSOD1 was highly active and catalyzed the dismutation of superoxide radicals. Furthermore, PvSOD1 showed activity over a broad range of pH and temperature. Inhibition studies suggested that PvSOD1 was inactivated by hydrogen peroxide, and peroxynitrite, but not by cyanide and azide. Since, PvSOD1 plays a central role in oxidative defense mechanism, therefore, characterization of PvSOD1 will be exploited in the screening of new superoxide dismutase inhibitors for their antimalarial activity.

  14. Development of a PET Radiotracer for Noninvasive Imaging of the Reactive Oxygen Species, Superoxide, in vivo

    PubMed Central

    Chu, Wenhua; Chepetan, Andre; Zhou, Dong; Shoghi, Kooresh I.; Xu, Jinbin; Dugan, Laura L.; Gropler, Robert J.; Mintun, Mark A.; Mach, Robert H.

    2014-01-01

    Reactive oxygen species (ROS) have been implicated in the pathogenesis of a wide range of human disease states and drug toxicities, but development of imaging tools to study ROS biology in vivo remains a challenge. Here we synthesized and validated a novel PET tracer (12) and its 18F radiolabeled version [18F]12 to allow PET (positron emission tomography) imaging of superoxide in vivo. Initial analysis of ROS reaction kinetics found that compound 12 was rapidly and selectively oxidized by superoxide, but not other ROS. Cell culture studies in EMT6 cells exposed to the cancer chemotherapeutic agent Doxorubicin (DOX), which activates the superoxide-generating enzyme, NADPH oxidase, showed that compound 12 was a sensitive and specific probe for superoxide in cells. The microPET imaging of heart in mice with DOX-induced cardiac inflammation observed 2-fold greater oxidation of [18F]12 in the DOX-treated mice compared to controls (p=0.02), the results were confirmed by distribution studies on organs subsequently removed from the mice and HPLC analysis of [18F] radioactivity compounds. These data indicate that compound 12 is a useful PET tracer to imaging ROS in vivo. PMID:24847866

  15. Overexpression of manganese superoxide dismutase promotes the survival of prostate cancer cells exposed to hyperthermia.

    PubMed

    Venkataraman, Sujatha; Wagner, Brett A; Jiang, Xiaohong; Wang, Hong P; Schafer, Freya Q; Ritchie, Justine M; Patrick, Burns C; Oberley, Larry W; Buettner, Garry R

    2004-10-01

    It has been hypothesized that exposure of cells to hyperthermia results in an increased flux of reactive oxygen species (ROS), primarily superoxide anion radicals, and that increasing antioxidant enzyme levels will result in protection of cells from the toxicity of these ROS. In this study, the prostate cancer cell line, PC-3, and its manganese superoxide dismutase (MnSOD)-overexpressing clones were subjected to hyperthermia (43 degrees C, 1 h). Increased expression of MnSOD increased the mitochondrial membrane potential (MMP). Hyperthermic exposure of PC-3 cells resulted in increased ROS production, as determined by aconitase inactivation, lipid peroxidation, and H2O2 formation with a reduction in cell survival. In contrast, PC-3 cells overexpressing MnSOD had less ROS production, less lipid peroxidation, and greater cell survival compared to PC-3 Wt cells. Since MnSOD removes superoxide, these results suggest that superoxide free radical or its reaction products are responsible for part of the cytotoxicity associated with hyperthermia and that MnSOD can reduce cellular injury and thereby enhance heat tolerance. PMID:15512801

  16. Curcumin Rescues Diabetic Renal Fibrosis by Targeting Superoxide-Mediated Wnt Signaling Pathways.

    PubMed

    Ho, Cheng; Hsu, Yung-Chien; Lei, Chen-Chou; Mau, Shu-Ching; Shih, Ya-Hsueh; Lin, Chun-Liang

    2016-03-01

    The purposes of this study were to investigate whether curcumin can weaken diabetic nephropathy by modulating both oxidative stress and renal injury from Wnt signaling mediation. Wnt5a/β-catenin depression and induction of superoxide synthesis are associated with high glucose (HG) induced transforming growth factor (TGF)-β1 and fibronectin expression in mesangial cells. Curcumin resumes HG depression of Wnt/β-catenin signaling and alleviates HG induction of superoxide, TGF-β1 and fibronectin expression in renal mesangial cell. Exogenous curcumin alleviated urinary total proteinuria and serum superoxide level in diabetic rats. Based on laser-captured microdissection for quantitative real-time polymerase chain reaction, it was found that diabetes significantly increased TGF-β1 and fibronectin expression in line with depressed Wnt5a expression. Curcumin treatment reduced the TGF-β1 and fibronectin activation and the inhibiting effect of diabetes on Wnt5a/β-catenin expression in renal glomeruli. Immunohistochemistry showed that curcumin treatment significantly reduced 8-hydroxy-2'-deoxyguanosine, TGF-β1 and fibronectin, and was in line with the restoration of the suppressed Wnt5a expression immunoreactivities in glomeruli of diabetic rats. Curcumin alleviated extracellular matrix accumulation in diabetic nephropathy by not only preventing the diabetes-mediated superoxide synthesis but also resuming downregulation of Wnt/β-catenin signaling. These findings suggest that regulation of Wnt activity by curcumin is a feasible alternative strategy to rescue diabetic renal injury. PMID:26992258

  17. A functional model for the cysteinate-ligated non-heme iron enzyme superoxide reductase (SOR).

    PubMed

    Kitagawa, Terutaka; Dey, Abhishek; Lugo-Mas, Priscilla; Benedict, Jason B; Kaminsky, Werner; Solomon, Edward; Kovacs, Julie A

    2006-11-15

    Superoxide reductases (SORs) are cysteine-ligated, non-heme iron enzymes that reduce toxic superoxide radicals (O2-). The functional role of the trans cysteinate, as well as the mechanism by which SOR reduces O2-, is unknown. Herein is described a rare example of a functional metalloenzyme analogue, which catalytically reduces superoxide in a proton-dependent mechanism, via a trans thiolate-ligated iron-peroxo intermediate, the first example of its type. Acetic-acid-promoted H2O2 release, followed by Cp2Co reduction, regenerates the active Fe(II) catalyst. The thiolate ligand and its trans positioning relative to the substrate are shown to contribute significantly to the catalyst's function, by lowering the redox potential, changing the spin state, and dramatically lowering the nuFe-O stretching frequency well-below that of any other reported iron-peroxo, while leaving nuO-O high, so as to favor superoxide reduction and Fe-O, as opposed to O-O, bond cleavage. Thus we provide critical insight into the relationship between the SOR structure and its function, as well as important benchmark parameters for characterizing highly unstable thiolate-ligated iron-peroxo intermediates. PMID:17090014

  18. Exogenous superoxide dismutase may lose its antidotal ability on rice leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  19. soxR, a locus governing a superoxide response regulon in Escherichia coli K-12.

    PubMed

    Tsaneva, I R; Weiss, B

    1990-08-01

    The nfo (endonuclease IV) gene of Escherichia coli is induced by superoxide generators such as paraquat (methyl viologen). An nfo'-lacZ operon fusion was used to isolate extragenic mutations affecting its expression. The mutations also affected the expression of glucose 6-phosphate dehydrogenase, Mn2(+)-superoxide dismutase (sodA), and three lacZ fusions to soi (superoxide-inducible) genes of unknown function. The mutations were located 2 kilobases clockwise of ssb at 92 min on the current linkage map. One set of mutations, in a new gene designated soxR, caused constitutive overexpression of nfo and the other genes. It included insertions or deletions affecting the carboxyl end of a 17-kilodalton polypeptide. In a soxR mutant, the expression of sodA, unlike that of nfo, was also regulated independently by oxygen tension. Two other mutants were isolated in which the target genes were noninducible; they had an increased sensitivity to killing by superoxide-generating compounds. One had a Tn10 insertion in or near soxR; the other had a multigene deletion encompassing soxR. Therefore, the region functions as a positive regulator because it encodes one or more products needed for the induction of nfo. Regulation is likely to be at the level of transcription because the mutations were able to affect the expression of an nfo'-lac operon fusion that contained the ribosome-binding site for lacZ. Some mutant plasmids that failed to suppress (or complement) constitutivity in trans had insertion mutations several hundred nucleotides upstream of soxR in the general region of a gene for a 13-kilodalton protein encoded by the opposite strand, raising the possibility of a second regulatory gene in this region. The result define a new regulon, controlled by soxR, mediating at least part of the global response to superoxide in E. coli. PMID:1695893

  20. Detection of superoxide production in stimulated and unstimulated living cells using new cyclic nitrone spin traps.

    PubMed

    Abbas, Kahina; Hardy, Micael; Poulhès, Florent; Karoui, Hakim; Tordo, Paul; Ouari, Olivier; Peyrot, Fabienne

    2014-06-01

    Reactive oxygen species (ROS), including superoxide anion and hydrogen peroxide (H2O2), have a diverse array of physiological and pathological effects within living cells depending on the extent, timing, and location of their production. For measuring ROS production in cells, the ESR spin trapping technique using cyclic nitrones distinguishes itself from other methods by its specificity for superoxide and hydroxyl radical. However, several drawbacks, such as the low spin trapping rate and the spontaneous and cell-enhanced decomposition of the spin adducts to ESR-silent products, limit the application of this method to biological systems. Recently, new cyclic nitrones bearing a triphenylphosphonium (Mito-DIPPMPO) or a permethylated β-cyclodextrin moiety (CD-DIPPMPO) have been synthesized and their spin adducts demonstrated increased stability in buffer. In this study, a comparison of the spin trapping efficiency of these new compounds with commonly used cyclic nitrone spin traps, i.e., 5,5-dimethyl-1-pyrroline N-oxide (DMPO), and analogs BMPO, DEPMPO, and DIPPMPO, was performed on RAW 264.7 macrophages stimulated with phorbol 12-myristate 13-acetate. Our results show that Mito-DIPPMPO and CD-DIPPMPO enable a higher detection of superoxide adduct, with a low (if any) amount of hydroxyl adduct. CD-DIPPMPO, especially, appears to be a superior spin trap for extracellular superoxide detection in living macrophages, allowing measurement of superoxide production in unstimulated cells for the first time. The main rationale put forward for this extreme sensitivity is that the extracellular localization of the spin trap prevents the reduction of the spin adducts by ascorbic acid and glutathione within cells. PMID:24662195

  1. 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.

  2. Leishmania pifanoi amastigotes avoid macrophage production of superoxide by inducing heme degradation.

    PubMed

    Pham, Nam-Kha; Mouriz, Jennifer; Kima, Peter E

    2005-12-01

    Whereas infections of macrophages by promastigote forms of Leishmania mexicana pifanoi induce the production of superoxide, infections by amastigotes barely induce superoxide production. Several approaches were employed to gain insight into the mechanism by which amastigotes avoid eliciting superoxide production. First, in experiments with nitroblue tetrazolium, we found that 25% of parasitophorous vacuoles (PVs) that harbor promastigotes are positive for the NADPH oxidase complex, in contrast to only 2% of PVs that harbor amastigotes. Second, confocal microscope analyses of infected cells labeled with antibodies to gp91phox revealed that this enzyme subunit is found in PVs that harbor amastigotes. Third, in immunoblots of subcellular fractions enriched with PVs from amastigote-infected cells and probed with antibodies to gp91phox, only the 65-kDa premature form of gp91phox was found. In contrast, subcellular fractions from macrophages that ingested zymosan particles contained both the 91- and 65-kDa forms of gp91phox. This suggested that only the immature form of gp91phox is recruited to PVs that harbor amastigotes. Given that gp91phox maturation is dependent on the availability of heme, we found that infections by Leishmania parasites induce an increase in heme oxygenase 1 (HO-1), the rate-limiting enzyme in heme degradation. Infections by amastigotes performed in the presence of metalloporphyrins, which are inhibitors of HO-1, resulted in superoxide production by infected macrophages. Taken together, we propose that Leishmania amastigotes avoid superoxide production by inducing an increase in heme degradation, which results in blockage of the maturation of gp91phox, which prevents assembly of the NADPH oxidase enzyme complex.

  3. Superoxide radical production in chicken skeletal muscle induced by acute heat stress.

    PubMed

    Mujahid, A; Yoshiki, Y; Akiba, Y; Toyomizu, M

    2005-02-01

    Heat stress is of major concern for poultry, especially in the hot regions of the world because of the resulting poor growth performance, immunosuppression, and high mortality. To assess superoxide (O2*-) production in mitochondria isolated from skeletal muscle of chickens (n = 4 to 8) exposed to acute heat stress, electron spin resonance (ESR) spectroscopy using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) as a spin trap agent and lucigenin-derived chemiluminescence (LDCL) method were applied. ESR spectra of suspensions containing mitochondria from control and acute heat-treated meat-type chickens showed similar hyperfine coupling constants (aN = 1.44 mT, aHbeta = 0.12 mT, and aHbeta = 0.11 mT) to those of DMPO-O2*- adducts observed in a hypoxanthine-xanthine oxidase system. Heat exposure resulted in enhancement of the DMPO-O2*- signal. The results using LDCL showed significantly enhanced superoxide production in heat stress-treated skeletal muscle mitochondria of meat-type chickens, whereas no such increase was observed in laying chickens. The enhancement of superoxide production in the former case was associated with heat-induced increments in rectal and muscle temperatures, leading to significant body weight loss. In contrast, the latter case showed no increase in temperatures, although there was a slight decrease in body weight gain. Percentage increases of superoxide production in the presence of carboxyatractylate, a specific inhibitor of adenine nucleotide translocator (ANT), were the same for skeletal muscle mitochondria from meat- and laying-type chickens from the control or heat stress-treated group. This finding suggests the irrelevance of ANT in the regulation of reactive oxygen species flux under heat stress conditions. The study provides the first evidence of superoxide anion production in the skeletal muscle mitochondria of meat-type chickens in response to acute heat stress.

  4. Ordering of neuronal apoptosis signaling: a superoxide burst precedes mitochondrial cytochrome c release in a growth factor deprivation model

    PubMed Central

    Lieven, Christopher J.; Thurber, Katherine A.; Levin, Emily J.

    2012-01-01

    Axonal injury to retinal ganglion cells, a defined central neuron, induces a burst of intracellular superoxide anion that precedes externalization of membrane phosphatidylserine and subsequent apoptotic cell death. Dismutation of superoxide prevents the signal and delays loss of these cells, consistent with superoxide being necessary for transduction of the axotomy signal. However, phosphatidylserine externalization is a relatively late step in apoptosis, and it is possible that the superoxide burst is not an early axotomy signal but rather a result of cytochrome c release from the mitochondrial inner membrane with consequent accumulation of reduced intermediates. Other possibilities are that both superoxide generation and cytochrome c release are induced in parallel by axotomy, or that cytochrome c release potentiates the effect of the superoxide burst. To distinguish these various possibilities, serum-deprived neuronal retinal cells were assayed in vitro for superoxide elevation and release of cytochrome c from mitochondria, and the distribution of these two markers across a large number of cells used to model the temporal ordering of events. Based on this model of factor-dependent cell death, superoxide precedes, and possibly potentiates, cytochrome c release, and thus the former is likely an early signal for certain types of neuronal apoptosis in the central nervous system. PMID:22411528

  5. Ordering of neuronal apoptosis signaling: a superoxide burst precedes mitochondrial cytochrome c release in a growth factor deprivation model.

    PubMed

    Lieven, Christopher J; Thurber, Katherine A; Levin, Emily J; Levin, Leonard A

    2012-06-01

    Axonal injury to retinal ganglion cells, a defined central neuron, induces a burst of intracellular superoxide anion that precedes externalization of membrane phosphatidylserine and subsequent apoptotic cell death. Dismutation of superoxide prevents the signal and delays loss of these cells, consistent with superoxide being necessary for transduction of the axotomy signal. However, phosphatidylserine externalization is a relatively late step in apoptosis, and it is possible that the superoxide burst is not an early axotomy signal but rather a result of cytochrome c release from the mitochondrial inner membrane with consequent accumulation of reduced intermediates. Other possibilities are that both superoxide generation and cytochrome c release are induced in parallel by axotomy, or that cytochrome c release potentiates the effect of the superoxide burst. To distinguish these various possibilities, serum-deprived neuronal retinal cells were assayed in vitro for superoxide elevation and release of cytochrome c from mitochondria, and the distribution of these two markers across a large number of cells used to model the temporal ordering of events. Based on this model of factor-dependent cell death, superoxide precedes, and possibly potentiates, cytochrome c release, and thus the former is likely an early signal for certain types of neuronal apoptosis in the central nervous system. PMID:22411528

  6. Elevated mitochondrial superoxide disrupts normal T-cell development to impair adaptive immune responses to an influenza challenge

    PubMed Central

    Case, Adam J.; McGill, Jodi L.; Tygrett, Lorraine T.; Shirasawa, Takuji; Spitz, Douglas R.; Waldschmidt, Thomas J.; Legge, Kevin L.; Domann, Frederick E.

    2010-01-01

    Reactive oxygen species (ROS) are critical in a broad spectrum of cellular processes including signaling, tumor progression, and innate immunity. The essential nature of ROS signaling in the immune systems of Drosophila and zebrafish has been demonstrated; however, the role of ROS, if any, in mammalian adaptive immune system development and function remains unknown. The current work provides the first clear demonstration that thymus specific elevation of mitochondrial superoxide (O2·−) disrupts normal T-cell development to impair function of the mammalian adaptive immune system. To assess the effect of elevated mitochondrial superoxide in the developing thymus, we used a T-cell specific knockout of manganese superoxide dismutase (i.e. SOD2) and have thus established a murine model to examine the role of mitochondrial superoxide in T-cell development. Conditional loss of SOD2 led to increased superoxide, apoptosis, and developmental defects in the T-cell population resulting in immunodeficiency and susceptibility to influenza A virus (IAV), H1N1. This phenotype was rescued with mitochondrially targeted superoxide scavenging drugs. These new findings demonstrate that loss of regulated levels of mitochondrial superoxide lead to aberrant T-cell development and function, and further suggest that manipulations of mitochondrial superoxide levels may significantly alter clinical outcomes resulting from viral infection. PMID:21130157

  7. Involvement of Extracellular Cu/Zn Superoxide Dismutase in Cotton Fiber Primary and Secondary Cell Wall Biosynthesis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extracellular Cu/Zn superoxide dismutases (CSDs) that catalyze the conversion of superoxide to hydrogen peroxide have been suggested to be involved in lignification of secondary walls in spinach, pine and aspen. In cotton fibers, hydrogen peroxide was proposed to be involved in the induction of seco...

  8. Concerted action of reduced glutathione and superoxide dismutase in preventing redox cycling of dihydroxypyrimidines, and their role in antioxidant defence.

    PubMed

    Winterbourn, C C; Munday, R

    1990-01-01

    Dialuric Acid, the reduced form of the beta-cell toxin alloxan, and the related fava bean derivatives divicine and isouramil, autoxidize rapidly in neutral solution by a radical mechanism. GSH promotes redox cycling of each compound, with concomitant GSH oxidation and H2O2 production. With superoxide dismutase present, there is a lag period in which little oxidation occurs, followed by rapid oxidation. GSH extends this lag and decreases the subsequent rate of oxidation, so that with superoxide dismutase and a sufficient excess of GSH, coupled oxidation of GSH and each pyrimidine is almost completely suppressed. This mechanism may be a means whereby GSH in combination with superoxide dismutase protects against the cytotoxic effects of these reactive pyrimidines. Superoxide dismutase may also protect cells against oxidative stress in other situations where GSH acts as a radical scavenger, and we propose that the concerted action of GSH and superoxide dismutase constitutes an important antioxidant defence. PMID:2354807

  9. 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.; Yang, Xiao -Qing; Qu, Deyang

    2014-10-28

    Superoxide reacts with carbonate solvents in Li–air batteries. Tris(pentafluorophenyl)borane is found to catalyze a more rapid superoxide (O2-) disproportionation reaction than the reaction between superoxide and propylene carbonate (PC). With this catalysis, the negative impact of the reaction between the electrolyte and O2-produced by the O2 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 order and the rate constants aremore » 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

  10. Dynamics of Superoxide Production and Decay in Natural Trichodesmium Colonies from the Sargasso Sea: Implications for Cell Signaling

    NASA Astrophysics Data System (ADS)

    Hansel, C. M.; Buchwald, C.; Diaz, J. M.; Dyhrman, S.; Van Mooy, B. A. S.

    2014-12-01

    Reactive oxygen species (ROS) are key players in the biogeochemistry of the ocean, where they serve a critical role in the cycling of carbon and metals. Research in the past decade has introduced phytoplankton and, most recently, heterotrophic bacteria as significant sources of ROS, including superoxide, within both photic and aphotic regions of the ocean. ROS are both beneficial and detrimental to life. For instance, superoxide is a vital inter- and intra-cellular signaling molecule, yet at high concentrations it induces lipid peroxidation and initiates programmed cell death (PCD). In fact, superoxide has been implicated in PCD in the nitrogen-fixing diazotroph Trichodesmium, presumably leading to the demise of blooms within oligotrophic marine systems. Here, we explore the rates of superoxide production and decay by natural Trichodesmium populations obtained from various surface waters in the Sargasso Sea. We investigate also the role of light and colony density and morphology (puff v. raft) on superoxide fluxes. We find that Trichodesmium colonies produce extracellular superoxide at extremely high rates in the dark that are on par with those of the toxic raphidophyte Chattonella. The rates of superoxide production, however, rapidly decline with increasing cell density pointing to a role for superoxide in cell signaling in these organisms. We also find extremely rapid extracellular superoxide degradation by Trichodesmium. Together, this likely reflects a need for these organisms to maintain ROS at levels that will support signaling but below the threshold level that triggers PCD or oxidative damage. We also show differences in the effect of light on superoxide fluxes as a function of Trichodesmium colony morphology, suggesting differences in either colony physiology or associated bacterial symbionts. These findings point to complex physiological, ecological, and physical influences on ROS dynamics in phytoplankton that require further exploration.

  11. Superoxide radicals increase transforming growth factor-{beta}1 and collagen release from human lung fibroblasts via cellular influx through chloride channels

    SciTech Connect

    Qi Shufan Hartog, Gertjan J.M. den; Bast, Aalt

    2009-05-15

    Reactive oxygen species (ROS) have been implicated in the pathogenesis of fibrosis. However, it remains unclear which ROS is the major cause. We hypothesize that superoxide elicits specific toxicity to human lung fibroblasts and plays an important role in the development of pulmonary fibrosis. In this study, superoxide generated from xanthine and xanthine oxidase activated lung fibroblasts by increasing the release of TGF-{beta}1 and collagen. This was associated with increased levels of intracellular superoxide. SOD and tempol, by scavenging respectively extracellular and intracellular superoxide, prevented the activation of fibroblasts induced by exposure to exogenous superoxide, whereas catalase did not. Moreover, hydrogen peroxide did not activate fibroblasts. Apparently, superoxide rather than hydrogen peroxide is involved in the regulation of TGF-{beta}1 and collagen release in lung fibroblasts. The chloride channel blocker, DIDS, inhibited the increase of intracellular superoxide levels induced by exogenous superoxide and consequently prevented the activation of fibroblasts. This suggests that the cellular influx of superoxide through chloride channels is essential for superoxide-induced activation of fibroblasts. ERK1/2 and p38 MAPKs are involved in the intracellular pathway leading to superoxide-induced fibroblasts activation. Superoxide possesses until now undiscovered specific pro-fibrotic properties in human lung fibroblasts. This takes place via the cellular influx of superoxide through chloride channels rather than via the formation of hydrogen peroxide.

  12. A novel amperometric biosensor for superoxide anion based on superoxide dismutase immobilized on gold nanoparticle-chitosan-ionic liquid biocomposite film.

    PubMed

    Wang, Lu; Wen, Wei; Xiong, Huayu; Zhang, Xiuhua; Gu, Haoshuang; Wang, Shengfu

    2013-01-01

    A novel superoxide anion (O(2)(-)) biosensor is proposed based on the immobilization of copper-zinc superoxide dismutase (SOD) in a gold nanoparticle-chitosan-ionic liquid (GNPs-CS-IL) biocomposite film. The SOD-based biosensor was constructed by one-step ultrasonic electrodeposition of GNP-CS-IL composite onto glassy carbon electrode (GCE), followed by immobilization of SOD on the modified electrode. Surface morphologies of a set of representative films were characterized by scanning electron microscopy. The electrochemical performance of the biosensor was evaluated by cyclic voltammetry and chronoamperometry. A pair of quasi-reversible redox peaks of SOD with a formal potential of 0.257V was observed at SOD/GNPs-CS-IL/GCE in phosphate buffer solution (PBS, 0.1M, pH 7.0). The effects of varying test conditions on the electrochemical behavior of the biosensor were investigated. Furthermore, several electrochemical parameters were calculated in detail. Based on the biomolecule recognition of the specific reactivity of SOD toward O(2)(-), the developed biosensor exhibited a fast amperometric response (<5s), wide linear range (5.6-2.7×10(3)nM), low detection limit (1.7nM), and excellent selectivity for the real-time measurement of O(2)(-). The proposed method is promising for estimating quantitatively the dynamic changes of O(2)(-) in biological systems. PMID:23245897

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

    PubMed Central

    2014-01-01

    Aim 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. Material and methods 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. Results 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. Conclusion 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. PMID:25023905

  14. 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. PMID:11237050

  15. Superoxide radical scavenging by phenolic bronchodilators under aprotic and aqueous conditions.

    PubMed

    Zwicker, K; Damerau, W; Dikalov, S; Scholtyssek, H; Schimke, I; Zimmer, G

    1998-08-01

    Asthmatic airway disease is accompanied by the appearance of inflammatory cells which produce reactive oxygen species (ROS). Therefore, the radical scavenging properties of the bronchodilators reproterol, fenoterol, salbutamol and terbutaline toward superoxide anion radicals and hydroperoxyl radicals were investigated in a model system by electron paramagnetic resonance spectroscopy (EPR) and photometric approaches. The substances under study showed activity in superoxide radical scavenging under aprotic and protic conditions as well. The efficiency of the reaction decreased in the order: fenoterol > salbutamol > reproterol > terbutaline > oxyfedrine when DMSO was used as an aprotic solvent. In an aqueous system, the rate constants decreased in the order: fenoterol > reproterol > salbutamol. It is suggested that the antioxidant effect of these beta2-agonists is an additional advantage in treatment of asthmatic lung disease, reducing the negative consequences of airway inflammation. PMID:9744566

  16. Observation of superoxide production during catalysis of Bacillus subtilis oxalate decarboxylase at pH 4.

    PubMed

    Twahir, Umar T; Stedwell, Corey N; Lee, Cory T; Richards, Nigel G J; Polfer, Nicolas C; Angerhofer, Alexander

    2015-03-01

    This contribution describes the trapping of the hydroperoxyl radical at a pH of 4 during turnover of wild-type oxalate decarboxylase and its T165V mutant using the spin-trap BMPO. Radicals were detected and identified by a combination of EPR and mass spectrometry. Superoxide, or its conjugate acid, the hydroperoxyl radical, is expected as an intermediate in the decarboxylation and oxidation reactions of the oxalate monoanion, both of which are promoted by oxalate decarboxylase. Another intermediate, the carbon dioxide radical anion was also observed. The quantitative yields of superoxide trapping are similar in the wild type and the mutant while it is significantly different for the trapping of the carbon dioxide radical anion. This suggests that the two radicals are released from different sites of the protein. PMID:25526893

  17. Corynebacterium glutamicum superoxide dismutase is a manganese-strict non-cambialistic enzyme in vitro.

    PubMed

    El Shafey, H M; Ghanem, S; Merkamm, M; Guyonvarch, A

    2008-01-01

    Superoxide dismutase (SOD) of Corynebacterium glutamicum was purified and characterized. The enzyme had a native molecular weight of about 80kDa, whereas a monomer with molecular weight of 24kDa was found on SDS-PAGE suggesting it to be homotetramer. The native SOD activity stained gel revealed a unique cytosolic enzyme. Supplementing growth media with manganese increased the specific activity significantly, while adding iron did not result in significant difference. No growth perturbation was observed with the supplemented media. In vitro metal removal and replacement studies revealed conservation of about 85% of the specific activity by substitution with manganese, while substitution with copper, iron, nickel or zinc did not restore any significant specific activity. Manganese was identified by atomic absorption spectrometer, while no signals corresponding to fixing other metallic elements were detected. Thus, C. glutamicum SOD could be considered a strict (non-cambialistic) manganese superoxide dismutase (MnSOD). PMID:16809027

  18. Enzyme release and superoxide anion production by human alveolar macrophages stimulated with immunoglobulin E.

    PubMed Central

    Joseph, M; Tonnel, A B; Capron, A; Voisin, C

    1980-01-01

    Human alveolar macrophages specifically released lysosomal beta-glucuronidase and neutral proteases when successively incubated with IgE, and then, for 30 min, with anti-IgE. Superoxide anion O2- generation was obtained when anti-IgE-opsonized zymosan was added to IgE-incubated cells. Macrophages from smokers excreted twice as much enzymes and superoxide as cells from non-smokers. It was possible to induce the specific release of beta-glucuronidase with normal alveolar macrophages successively incubated with the serum of patients allergic to house dust or to grass pollen and then with the specific allergen. This characteristic opens the field to a direct test for allergic sera by analogy with the allergen-induced degranulation test of sensitized basophils. PMID:6254706

  19. Biphasic Superoxide Generation in Potato Tubers. A Self-Amplifying Response to Stress1

    PubMed Central

    Johnson, S.M.; Doherty, S.J.; Croy, R.R.D.

    2003-01-01

    Potato (Solanum tuberosum) cultivars differ quantitatively in their responses to mechanical stress including the ability to synthesize melanin pigments in tuber tissues. Investigations into the cellular events induced by mechanical stress on tuber tissues have shown that an early cellular response is a significant and rapid synthesis of superoxide radicals. This burst of radical production distinctively displays a reproducible biphasic pattern over time with peaks of generation at 2 and 5 h. A concomitant consequence of the generation of these free radicals is elevated levels of oxidatively modified tuber proteins. Both radical generation and protein modification vary between cultivars but both are directly proportional to the amount of melanin pigments produced. Cell-free extracts of mechanically stressed tissues, pectic fragments, and scission products generated from cell walls are able to induce superoxide generation in non-stressed tissues, indicating the participation of a biologically active factor that induces a further a phase of radical synthesis. PMID:12644693

  20. Tat-NR2B9c prevents excitotoxic neuronal superoxide production

    PubMed Central

    Chen, Yanting; Brennan-Minnella, Angela M; Sheth, Sunil; El-Benna, Jamel; Swanson, Raymond A

    2015-01-01

    The Tat-NR2B9c peptide has shown clinical efficacy as a neuroprotective agent in acute stroke. Tat-NR2B9c is designed to prevent nitric oxide (NO) production by preventing postsynaptic density protein 95 (PSD-95) binding to N-methyl-D-aspartate (NMDA) receptors and neuronal nitric oxide synthase; however, PSD-95 is a scaffolding protein that also couples NMDA receptors to other downstream effects. Here, using neuronal cultures, we show that Tat-NR2B9c also prevents NMDA-induced activation of neuronal NADPH oxidase, thereby blocking superoxide production. Given that both superoxide and NO are required for excitotoxic injury, the neuroprotective effect of Tat-NR2B9c may alternatively be attributable to uncoupling neuronal NADPH oxidase from NMDA receptor activation. PMID:25669908

  1. Observation of Superoxide Production During Catalysis of Bacillus subtilis Oxalate Decarboxylase at pH4

    PubMed Central

    Twahir, Umar T.; Stedwell, Corey N.; Lee, Cory T.; Richards, Nigel G. J.; Polfer, Nicolas C.; Angerhofer, Alexander

    2015-01-01

    This contribution describes the trapping of the hydroperoxyl radical at a pH of 4 during turnover of wild-type oxalate decarboxylase and its T165V mutant using the spin trap BMPO. Radicals were detected and identified by a combination of EPR and mass spectrometry. Superoxide, or its conjugate acid, the hydroperoxyl radical, is expected as an intermediate in the decarboxylation and oxidation reactions of the oxalate monoanion both of which are promoted by oxalate decarboxylase. Another intermediate, the carbon dioxide radical anion was also observed. The quantitative yields of superoxide trapping is similar in the wild type and the mutant while it is significantly different for the trapping of the carbon dioxide radical anion. This suggests that the two radicals are released from different sites of the protein. PMID:25526893

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

    PubMed

    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(•)- 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(•)- and H2O2 was done using nitroblue tetrazolium (NBT) and 3,3',5,5'-tetramethyl benzidine dihydrochloride hydrate (TMB), respectively. Apoplastic level of O2(•)- 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(•)- while the differentiating zone of axis (radicle) requires H2O2 for cell wall stiffening.

  3. Studies on the inhibitory effects of caffeoylquinic acids on monocyte migration and superoxide ion production.

    PubMed

    Peluso, G; De Feo, V; De Simone, F; Bresciano, E; Vuotto, M L

    1995-05-01

    Three caffeoylquinic acids, isolated from the Peruvian plants Tessaria integrifolia and Mikania cordifolia that are used medicinally as anti-inflammatory agents, were tested for their activities on monocyte migration and superoxide anion production. 3,5-Di-O-caffeoylquinic and 4,5-di-O-caffeoylquinic acids exhibited an appreciable anti-inflammatory activity in vitro, while the tricaffeoyl derivative was inactive.

  4. Equine digital veins are more sensitive to superoxide anions than digital arteries.

    PubMed

    Lapo, Rock Allister; Gogny, Marc; Chatagnon, Gérard; Lalanne, Valérie; Harfoush, Khaled; Assane, Moussa; Desfontis, Jean-Claude; Mallem, Mohamed Yassine

    2014-10-01

    This work was designed to investigate (i) the effect of superoxide dismutase (SOD) inhibition on endothelial function and (ii) the free radical-induced endothelial dysfunction in equine digital veins (EDVs) and equine digital arteries (EDAs) isolated from healthy horses. EDV and EDA rings were suspended in a 5 ml organ bath containing Krebs solution. After a 60 min equilibration period, EDV and EDA rings were contracted with phenylephrine. Then, cumulative concentration-response curves (CCRCs) to acetylcholine were performed. In both EDVs and EDAs, acetylcholine (1 nM to 10 µM) produced concentration-dependent relaxation. We investigated the influence of SOD inhibition by diethyldithiocarbamate (DETC; 100 µM), a CuZnSOD inhibitor, on EDAs and EDVs relaxant responses to acetylcholine. Acetylcholine -mediated relaxation was impaired by DETC only in EDVs. SOD activity assayed by a xanthine-xanthine oxidase method was higher in EDAs compared with EDVs (P<0.05). CCRCs to acetylcholine established in the presence of pyrogallol (30 µM) or homocysteine (20 µM), two superoxide anions generating systems showed that in both EDVs and EDAs, the acetylcholine-mediated relaxation was significantly impaired by pyrogallol and homocysteine. This impairment was more pronounced in EDVs than in EDAs. Moreover, the pyrogallol-induced impairment of acetylcholine-mediated relaxation was potentiated by DETC to a greater extent in EDVs. We concluded that due to the lower activity of SOD, EDVs are more sensitive to superoxide anions than EDAs. So, any alteration of superoxide anions metabolism is likely to have a more important impact on venous rather than arterial relaxation. PMID:25014758

  5. Contradictory Effects of Superoxide and Hydrogen Peroxide on KCa3.1 in Human Endothelial Cells

    PubMed Central

    Choi, Shinkyu; Na, Hye-Young; Kim, Ji Aee; Cho, Sung-Eun

    2013-01-01

    Reactive oxygen species (ROS) are generated in various cells, including vascular smooth muscle and endothelial cells, and regulate ion channel functions. KCa3.1 plays an important role in endothelial functions. However, the effects of superoxide and hydrogen peroxide radicals on the expression of this ion channel in the endothelium remain unclear. In this study, we examined the effects of ROS donors on KCa3.1 expression and the K+ current in primary cultured human umbilical vein endothelial cells (HUVECs). The hydrogen peroxide donor, tert-butyl hydroperoxide (TBHP), upregulated KCa3.1 expression, while the superoxide donors, xanthine/xanthine oxidase mixture (X/XO) and lysopho-sphatidylcholine (LPC), downregulated its expression, in a concentration-dependent manner. These ROS donor effects were prevented by antioxidants or superoxide dismustase. Phosphorylated extracellular signal-regulated kinase (pERK) was upregulated by TBHP and downregulated by X/XO. In addition, repressor element-1-silencing transcription factor (REST) was downregulated by TBHP, and upregulated by X/XO. Furthermore, KCa3.1 current, which was activated by clamping cells with 1 µM Ca2+ and applying the KCa3.1 activator 1-ethyl-2-benzimidazolinone, was further augmented by TBHP, and inhibited by X/XO. These effects were prevented by antioxidants. The results suggest that hydrogen peroxide increases KCa3.1 expression by upregulating pERK and downregulating REST, and augments the K+ current. On the other hand, superoxide reduces KCa3.1 expression by downregulating pERK and upregulating REST, and inhibits the K+ current. ROS thereby play a key role in both physiological and pathological processes in endothelial cells by regulating KCa3.1 and endothelial function. PMID:23776393

  6. Reactions between a superoxide anion and alkyl bromides in dimethyl sulfoxide

    NASA Astrophysics Data System (ADS)

    Pomeshchenko, A. I.; Efimova, I. V.; Dmitruk, A. F.; Zarechnaya, O. M.; Opeida, I. A.

    2011-10-01

    The activation parameters of the reactions between a superoxide anion (O{2/·-}) and alkyl bromides are measured. An ab initio study of the transition states for various mechanisms of this reaction is performed. The mechanism of radical separation in a polar solvent becomes competitive upon an increase in the number of alkyl groups in an alkyl bromide molecule and depends on their arrangement relative to a reaction center.

  7. Absence of superoxide dismutase activity causes nuclear DNA fragmentation during the aging process

    SciTech Connect

    Muid, Khandaker Ashfaqul; Karakaya, Hüseyin Çaglar; Koc, Ahmet

    2014-02-07

    Highlights: • Aging process increases ROS accumulation. • Aging process increases DNA damage levels. • Absence of SOD activity does not cause DNA damage in young cells. • Absence of SOD activity accelerate aging and increase oxidative DNA damages during the aging process. - Abstract: Superoxide dismutases (SOD) serve as an important antioxidant defense mechanism in aerobic organisms, and deletion of these genes shortens the replicative life span in the budding yeast Saccharomyces cerevisiae. Even though involvement of superoxide dismutase enzymes in ROS scavenging and the aging process has been studied extensively in different organisms, analyses of DNA damages has not been performed for replicatively old superoxide dismutase deficient cells. In this study, we investigated the roles of SOD1, SOD2 and CCS1 genes in preserving genomic integrity in replicatively old yeast cells using the single cell comet assay. We observed that extend of DNA damage was not significantly different among the young cells of wild type, sod1Δ and sod2Δ strains. However, ccs1Δ mutants showed a 60% higher amount of DNA damage in the young stage compared to that of the wild type cells. The aging process increased the DNA damage rates 3-fold in the wild type and more than 5-fold in sod1Δ, sod2Δ, and ccs1Δ mutant cells. Furthermore, ROS levels of these strains showed a similar pattern to their DNA damage contents. Thus, our results confirm that cells accumulate DNA damages during the aging process and reveal that superoxide dismutase enzymes play a substantial role in preserving the genomic integrity in this process.

  8. 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

  9. Thermodynamic and kinetic considerations for the reaction of semiquinone radicals to form superoxide and hydrogen peroxide

    PubMed Central

    Song, Yang; Buettner, Garry R.

    2010-01-01

    The quinone/semiquinone/hydroquinone triad (Q/SQ•−/H2Q) represents a class of compounds that has great importance in a wide range of biological processes. The half-cell reduction potentials of these redox couples in aqueous solutions at neutral pH, E°′, provide a window to understanding the thermodynamic and kinetic characteristics of this triad and their associated chemistry and biochemistry in vivo. Substituents on the quinone ring can significantly influence the electron density “on the ring” and thus modify E°′ dramatically. E°′ of the quinone governs the reaction of semiquinone with dioxygen to form superoxide. At near-neutral pH the pKa's of the hydroquinone are outstanding indicators of the electron density in the aromatic ring of the members of these triads (electrophilicity) and thus are excellent tools to predict half-cell reduction potentials for both the one-electron and two-electron couples, which in turn allow estimates of rate constants for the reactions of these triads. For example, the higher the pKa's of H2Q, the lower the reduction potentials and the higher the rate constants for the reaction of SQ•− with dioxygen to form superoxide. However, hydroquinone autoxidation is controlled by the concentration of di-ionized hydroquinone; thus, the lower the pKa's the less stable H2Q to autoxidation. Catalysts, e.g., metals and quinone, can accelerate oxidation processes; by removing superoxide and increasing the rate of formation of quinone, superoxide dismutase can accelerate oxidation of hydroquinones and thereby increase the flux of hydrogen peroxide. The principal reactions of quinones are with nucleophiles via Michael addition, for example, with thiols and amines. The rate constants for these addition reactions are also related to E°′. Thus, pKa's of a hydroquinone and E°′ are central to the chemistry of these triads. PMID:20493944

  10. Some aspects of the chemistry and biology of the superoxide radical anion

    NASA Astrophysics Data System (ADS)

    Faraggi, M.; Houée-Levin, C.

    1999-01-01

    There is increasing evidence that the superoxide radical anion is produced in many biological reactions and especially in respiration. Also, there are many indications that the participation of this radical in certain biological reactions can ultimately have deleterious effects on the health and well being of certain individuals. Based on pulse radiolytic method of generating superoxide its physical and chemical properties are described. This review gives the present state of research on the formation and reactivity of the superoxide radical anion in biological systems, the physiological function of superoxide dismutase, as well as several enzymatic reactions for which the participation of the radical has not yet been conclusively established. Les signes de la production du radical anion superoxyde lors de nombreuses réactions biologiques et surtout lors de la respiration sont maintenant bien établis. De nombreux résultats montrent que la participation de ce radical dans certaines réactions biologiques peut conduire a des effets délétères préjudiciables à la santé. Bases sur la génération du radical superoxyde par la méthode de radiolyse pulsée, ses propriétés physiques et chimiques seront analysées. La présentation inclura l'état actuel de la recherche sur la formation et la réactivité de l'anion superoxyde dans les systèmes biologiques, la fonction physiologiques de la superoxyde dismutase aussi bien que celles de plusieurs autres réactions enzymatiques, pour lesquelles la participation de ce radical n'a pas encore été clairement établie.

  11. 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

  12. 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.

  13. Purification and characterization of iron-cofactored superoxide dismutase from Enteromorpha linza

    NASA Astrophysics Data System (ADS)

    Lü, Mingsheng; Cai, Ruanhong; Wang, Shujun; Liu, Zhaopu; Jiao, Yuliang; Fang, Yaowei; Zhang, Xiaoxin

    2013-11-01

    A superoxide dismutase was purified from Enteromorpha linza using a simple and safe procedure, which comprised phosphate buffer extraction, ammonium sulphate precipitation, ion exchange chromatography on Q-sepharose column, and gel filtration chromatography on Superdex 200 10/300GL. The E. linza superoxide dismutase ( ElSOD) was purified 103.6-fold, and a yield of 19.1% and a specific activity of 1 750 U/mg protein were obtained. The SDS-PAGE exhibited ElSOD a single band near 23 kDa and the gel filtration study showed ElSOD's molecular weight is near 46 kDa in nondenatured condition, indicating it's a homodimeric protein. El SOD is an iron-cofactored superoxide dismutase (Fe-SOD) because it was inhibited by hydrogen peroxide, insensitive to potassium cyanide. The optimal temperature for its maximal enzyme activity was 35°C, and it still had 29.8% relative activity at 0°C, then ElSOD can be classified as a cold-adapted enzyme. ElSOD was stable when temperature was below 40°C or the pH was within the range of 5-10. The first 11 N-terminal amino acids of ElSOD were ALELKAPPYEL, comparison of its N-terminal sequence with other Fe-SOD N-terminal sequences at the same position suggests it is possibly a chloroplastic Fe-SOD.

  14. A Zostera marina manganese superoxide dismutase gene involved in the responses to temperature stress.

    PubMed

    Liu, Jiao; Tang, Xuexi; Wang, You; Zang, Yu; Zhou, Bin

    2016-01-10

    Superoxide dismutase (SOD) is an essential enzyme playing a pivotal role in the protection mechanism against oxidative stress by reducing superoxide radicals. In the present study, the full-length cDNA sequence of manganese superoxide dismutase was identified from Zostera marina (ZmMnSOD) via raid amplification of cDNA ends (RACE) technique and expressed sequence tags (ESTs) analysis. The open reading frame (ORF) encoded a polypeptide of 254 amino acid residues, which shared 69%-77% similarity with previous identified SODs. Analysis of the deduced amino acid revealed conserved features, including functional domains, signature motifs and metal binding sites. Phylogenetic analysis revealed that ZmMnSOD was closer to the SODs from angiosperm than those from other organisms. The mRNA expression level of ZmMnSOD at different temperatures was investigated using real-time PCR and it was significantly up-regulated from 5°C to 15°C, and then dramatically down-regulated. The recombinant ZmMnSOD protein was purified and exhibited Mn(2+) ions dependency specific enzymatic activity and strong antioxidant activity over a wide temperature range. All these results indicate that ZmMnSOD is an authentic member of the plant SOD family and may play important roles in minimizing the effect of oxidative damage in Z. marina against temperature stress and affect the adaptability of Z. marina to global warming.

  15. A Zostera marina manganese superoxide dismutase gene involved in the responses to temperature stress.

    PubMed

    Liu, Jiao; Tang, Xuexi; Wang, You; Zang, Yu; Zhou, Bin

    2016-01-10

    Superoxide dismutase (SOD) is an essential enzyme playing a pivotal role in the protection mechanism against oxidative stress by reducing superoxide radicals. In the present study, the full-length cDNA sequence of manganese superoxide dismutase was identified from Zostera marina (ZmMnSOD) via raid amplification of cDNA ends (RACE) technique and expressed sequence tags (ESTs) analysis. The open reading frame (ORF) encoded a polypeptide of 254 amino acid residues, which shared 69%-77% similarity with previous identified SODs. Analysis of the deduced amino acid revealed conserved features, including functional domains, signature motifs and metal binding sites. Phylogenetic analysis revealed that ZmMnSOD was closer to the SODs from angiosperm than those from other organisms. The mRNA expression level of ZmMnSOD at different temperatures was investigated using real-time PCR and it was significantly up-regulated from 5°C to 15°C, and then dramatically down-regulated. The recombinant ZmMnSOD protein was purified and exhibited Mn(2+) ions dependency specific enzymatic activity and strong antioxidant activity over a wide temperature range. All these results indicate that ZmMnSOD is an authentic member of the plant SOD family and may play important roles in minimizing the effect of oxidative damage in Z. marina against temperature stress and affect the adaptability of Z. marina to global warming. PMID:26410038

  16. Immunohistochemical identification and quantitative analysis of cytoplasmic Cu/Zn superoxide dismutase in mouse organogenesis

    PubMed Central

    Yon, Jung-Min; Baek, In-Jeoung; Lee, Se-Ra; Kim, Mi-Ra; Lee, Beom Jun; Yun, Young Won

    2008-01-01

    Cytoplasmic Cu/Zn superoxide dismutase (SOD1) is an antioxidant enzyme that converts superoxide to hydrogen peroxide in cells. Its spatial distribution matches that of superoxide production, allowing it to protect cells from oxidative stress. SOD1 deficiencies result in embryonic lethality and a wide range of pathologies in mice, but little is known about normal SOD1 protein expression in developing embryos. In this study, the expression pattern of SOD1 was investigated in post-implantation mouse embryos and extraembryonic tissues, including placenta, using Western blotting and immunohistochemical analyses. SOD1 was detected in embryos and extraembryonic tissues from embryonic day (ED) 8.5 to 18.5. The signal in embryos was observed at the lowest level on ED 9.5-11.5, and the highest level on ED 17.5-18.5, while levels remained constant in the surrounding extraembryonic tissues during all developmental stages examined. Immunohistochemical analysis of SOD1 expression on ED 13.5-18.5 revealed its ubiquitous distribution throughout developing organs. In particular, high levels of SOD1 expression were observed in the ependymal epithelium of the choroid plexus, ganglia, sensory cells of the olfactory and vestibulocochlear epithelia, blood cells and vessels, hepatocytes and hematopoietic cells of the liver, lymph nodes, osteogenic tissues, and skin. Thus, SOD1 is highly expressed at late stages of embryonic development in a cell- and tissue-specific manner, and can function as an important antioxidant enzyme during organogenesis in mouse embryos. PMID:18716442

  17. Induction and inactivation of catalase and superoxide dismutase of Escherichia coli by ozone

    SciTech Connect

    Whiteside, C.; Hassan, H.M.

    1987-09-01

    Oxyradicals have been implicated in ozone (O/sub 3/) toxicity and in other oxidant stress. In this study, we investigated the effects of O/sub 3/ on the biosynthesis of the antioxidant enzymes catalase and superoxide dismutase in Escherichia coli to determine their role in the defense against ozone toxicity. Inhibition of growth and loss of viability were observed in cultures exposed to ozone. Results also showed an increase in the activities of catalase and superoxide dismutase in cultures exposed to ozone, which was shown to be due to true induction rather than activation of preexisting apoproteins. Cessation of O/sub 3/ exposure resulted in 30 min of continual high rate of catalase biosynthesis followed by a gradual decrease in the level of the enzyme approaching that of control cultures. This decrease was attributed to a concomitant cessation of de novo enzyme synthesis and dilution of preexisting enzyme by cellular growth. Ozonation of cell-free extracts showed that superoxide dismutase and catalase are subject to oxidative inactivation by ozone. In vivo induction of these enzymes may represent an adaptive response evolved to protect cells against ozone toxicity.

  18. Reaction mechanism of superoxide generation during ubiquinol oxidation by the cytochrome bc1 complex.

    PubMed

    Yin, Ying; Yang, Shaoqing; Yu, Linda; Yu, Chang-An

    2010-05-28

    In addition to its main functions of electron transfer and proton translocation, the cytochrome bc(1) complex (bc(1)) also catalyzes superoxide anion (O(2)(*)) generation upon oxidation of ubiquinol in the presence of molecular oxygen. The reaction mechanism of superoxide generation by bc(1) remains elusive. The maximum O(2)(*) generation activity is observed when the complex is inhibited by antimycin A or inactivated by heat treatment or proteinase K digestion. The fact that the cytochrome bc(1) complex with less structural integrity has higher O(2)(*)-generating activity encouraged us to speculate that O(2)(*) is generated inside the complex, perhaps in the hydrophobic environment of the Q(P) pocket through bifurcated oxidation of ubiquinol by transferring its two electrons to a high potential electron acceptor, iron-sulfur cluster, and a low potential heme b(L) or molecular oxygen. If this speculation is correct, then one should see more O(2)(*) generation upon oxidation of ubiquinol by a high potential oxidant, such as cytochrome c or ferricyanide, in the presence of phospholipid vesicles or detergent micelles than in the hydrophilic conditions, and this is indeed the case. The protein subunits, at least those surrounding the Q(P) pocket, may play a role either in preventing the release of O(2)(*) from its production site to aqueous environments or in preventing O(2) from getting access to the hydrophobic Q(P) pocket and might not directly participate in superoxide production. PMID:20371599

  19. Modification of inflammatory response to implanted biomedical materials in vivo by surface bound superoxide dismutase mimics.

    PubMed

    Udipi, K; Ornberg, R L; Thurmond, K B; Settle, S L; Forster, D; Riley, D

    2000-09-15

    The healing response to implanted biomedical materials involves varying degrees and stages of inflammation and healing which in some cases leads to device failure. In this article, we describe synthetic methods and in vivo results of a novel surface treatment for biomedical materials involving covalent conjugation of a low molecular weight superoxide dismutase mimic (SODm), which imparts anti-inflammatory character to the material. SODm investigated in this study are a new class of anti-inflammatory drugs consisting of a Mn(II) complex of a macrocyclic polyamine ring that catalyze the dismutation of superoxide at rates equivalent to that of native enzyme. The SODms were covalently linked to small disks of ultra-high molecular weight polyethylene, poly(etherurethane urea), and tantalum metal at two concentrations and implanted in a subcutaneous rat implant model for 3, 7, 14, and 28 days. Histological examination of the implant tissue performed at 3 and 28 days revealed striking anti-inflammatory effects on both acute and chronic inflammatory responses. At 3 days, the formation of a neutrophil-rich acute inflammatory infiltrate seen in control implants was inhibited for all three materials treated with SODm. At 28 days, foreign body giant cell formation (number of FBGCs per field) and fibrous capsule formation (mean thickness of implant capsule) were also significantly inhibited over untreated control implants. A mechanism based on our current understanding of superoxide as an inflammatory mediator at implanted biomedical materials is proposed.

  20. Inhibition of autoxidation of divicine and isouramil by the combination of superoxide dismutase and reduced glutathione.

    PubMed

    Winterbourn, C C

    1989-06-01

    The effects of GSH on the autoxidation of the fava bean pyrimidine aglycones, divicine and isouramil, and on acid-hydrolyzed vicine (provisional identification 2-amino-4,5,6-trihydroxypyrimidine) have been studied. GSH alone promoted redox cycling of each compound, with concomitant GSH oxidation and H2O2 production. In the presence of superoxide dismutase, there is a lag period during which little pyrimidine oxidation occurs, followed by a period of accelerated oxidation. With the three pyrimidines, increasing concentrations of GSH extended this lag period and progressively decreased subsequent rates of both pyrimidine oxidation and O2 uptake. No GSH oxidation or O2 uptake occurred during the lag. These results show that the combination of GSH and superoxide dismutase is able to inhibit redox cycling of the pyrimidines. With a 10-fold excess of GSH over isouramil or acid-hydrolyzed vicine (20-fold with divicine) this coupled oxidation of GSH and the pyrimidine is almost completely suppressed. This mechanism may be a means whereby GSH in combination with superoxide dismutase protects against the cytotoxic effects of these reactive pyrimidines. PMID:2730000

  1. Stimulation of superoxide production increases fungicidal action of miconazole against Candida albicans biofilms

    PubMed Central

    De Cremer, Kaat; De Brucker, Katrijn; Staes, Ines; Peeters, Annelies; Van den Driessche, Freija; Coenye, Tom; Cammue, Bruno P. A.; Thevissen, Karin

    2016-01-01

    We performed a whole-transcriptome analysis of miconazole-treated Candida albicans biofilms, using RNA-sequencing. Our aim was to identify molecular pathways employed by biofilm cells of this pathogen to resist action of the commonly used antifungal miconazole. As expected, genes involved in sterol biosynthesis and genes encoding drug efflux pumps were highly induced in biofilm cells upon miconazole treatment. Other processes were affected as well, including the electron transport chain (ETC), of which eight components were transcriptionally downregulated. Within a diverse set of 17 inhibitors/inducers of the transcriptionally affected pathways, the ETC inhibitors acted most synergistically with miconazole against C. albicans biofilm cells. Synergy was not observed for planktonically growing C. albicans cultures or when biofilms were treated in oxygen-deprived conditions, pointing to a biofilm-specific oxygen-dependent tolerance mechanism. In line, a correlation between miconazole’s fungicidal action against C. albicans biofilm cells and the levels of superoxide radicals was observed, and confirmed both genetically and pharmacologically using a triple superoxide dismutase mutant and a superoxide dismutase inhibitor N-N′-diethyldithiocarbamate, respectively. Consequently, ETC inhibitors that result in mitochondrial dysfunction and affect production of reactive oxygen species can increase miconazole’s fungicidal activity against C. albicans biofilm cells. PMID:27272719

  2. Superoxide dismutase restores endothelium-dependent arteriolar dilatation during acute infusion of nicotine.

    PubMed

    Mayhan, W G; Sharpe, G M

    1998-10-01

    We previously showed [Am. J. Physiol. 272 (Heart Circ. Physiol. 41): H2337-H2342, 1997] that nicotine impairs endothelium-dependent arteriolar dilatation. However, mechanisms that accounted for the effect of nicotine on endothelium-dependent vasodilatation were not examined. Thus the goal of this study was to examine the role of oxygen radicals in nicotine-induced impairment of arteriolar reactivity. We measured diameter of cheek pouch resistance arterioles (approximately 50 micrometer diameter) in response to endothelium-dependent (ACh and ADP) and -independent (nitroglycerin) agonists before and after infusion of vehicle or nicotine in the absence or presence of superoxide dismutase. ACh, ADP, and nitroglycerin produced dose-related dilatation of cheek pouch arterioles before infusion of vehicle or nicotine. Infusion of vehicle, in the absence or presence of superoxide dismutase (150 U/ml), did not alter endothelium-dependent or -independent arteriolar dilatation. In contrast, infusion of nicotine (2 microgram . kg-1 . min-1) impaired endothelium-dependent, but not -independent, arteriolar dilatation. In addition, the effect of nicotine on endothelium-dependent vasodilatation was reversed by topical application of superoxide dismutase. We suggest that nicotine impairs endothelium-dependent arteriolar dilatation via an increase in the synthesis/release of oxygen-derived free radicals.

  3. Mechanism of enhanced superoxide production in the cytochrome b(6)f complex of oxygenic photosynthesis.

    PubMed

    Baniulis, Danas; Hasan, S Saif; Stofleth, Jason T; Cramer, William A

    2013-12-17

    The specific rate of superoxide (O2(•-)) production in the purified active crystallizable cytochrome b6f complex, normalized to the rate of electron transport, has been found to be more than an order of magnitude greater than that measured in isolated yeast respiratory bc1 complex. The biochemical and structural basis for the enhanced production of O2(•-) in the cytochrome b6f complex compared to that in the bc1 complex is discussed. The higher rate of superoxide production in the b6f complex could be a consequence of an increased residence time of plastosemiquinone/plastoquinol in its binding niche near the Rieske protein iron-sulfur cluster, resulting from (i) occlusion of the quinone portal by the phytyl chain of the unique bound chlorophyll, (ii) an altered environment of the proton-accepting glutamate believed to be a proton acceptor from semiquinone, or (iii) a more negative redox potential of the heme bp on the electrochemically positive side of the complex. The enhanced rate of superoxide production in the b6f complex is physiologically significant as the chloroplast-generated reactive oxygen species (ROS) functions in the regulation of excess excitation energy, is a source of oxidative damage inflicted during photosynthetic reactions, and is a major source of ROS in plant cells. Altered levels of ROS production are believed to convey redox signaling from the organelle to the cytosol and nucleus.

  4. Electrochemical characterization and application of azurin-modified gold electrodes for detection of superoxide.

    PubMed

    Shleev, Sergey; Wetterö, Jonas; Magnusson, Karl-Eric; Ruzgas, Tautgirdas

    2006-08-15

    A novel biosensor for superoxide radical (O(2)(*-)) detection based on Pseudomonas aeruginosa azurin immobilized on gold electrode was designed. The rate constant of azurin reduction by O(2)(*-) was found to be 10(5)M(-1)s(-1) in solution and five times lower, i.e., 0.2 x 10(5)M(-1)s(-1), for azurin coupled to gold by 3,3'-dithiobis(sulfosuccinimidylpropionate) (DTSSP). The electron transfer rate between the protein and the electrode ranged from 2 to 6s(-1). The sensitivity of this biosensor to O(2)(*-) was 6.8 x 10(2)Am(-2)M(-1). The response to the interference substances, such as uric acid, H(2)O(2), and dimethylsulfoxide was negligible below 10 microM. The electrode was applied in three O(2)(*-) generating systems: (i) xanthine oxidase (XOD), (ii) potassium superoxide (KO(2)), and (iii) stimulated neutrophil granulocytes. The latter was compared with luminol-amplified chemiluminescence. The biosensor responded to O(2)(*-) in all three environments, and the signals were antagonized by superoxide dismutase.

  5. Nitric Oxide and Superoxide Anion Balance in Rats Exposed to Chronic and Long Term Intermittent Hypoxia

    PubMed Central

    Siques, Patricia; López de Pablo, Ángel Luis; Brito, Julio; Arribas, Silvia M.; Naveas, Nelson; González, M. Carmen; León-Velarde, Fabiola; López, M. Rosario

    2014-01-01

    Work at high altitude in shifts exposes humans to a new form of chronic intermittent hypoxia, with still unknown health consequences. We have established a rat model resembling this situation, which develops a milder form of right ventricular hypertrophy and pulmonary artery remodelling compared to continuous chronic exposure. We aimed to compare the alterations in pulmonary artery nitric oxide (NO) availability induced by these forms of hypoxia and the mechanisms implicated. Rats were exposed for 46 days to normoxia or hypobaric hypoxia, either continuous (CH) or intermittent (2 day shifts, CIH2x2), and assessed: NO and superoxide anion availability (fluorescent indicators and confocal microscopy); expression of phosphorylated endothelial NO synthase (eNOS), NADPH-oxidase (p22phox), and 3-nitrotyrosine (western blotting); and NADPH-oxidase location (immunohistochemistry). Compared to normoxia, (1) NO availability was reduced and superoxide anion was increased in both hypoxic groups, with a larger effect in CH, (2) eNOS expression was only reduced in CH, (3) NADPH-oxidase was similarly increased in both hypoxic groups, and (4) 3-nitrotyrosine was increased to a larger extent in CH. In conclusion, intermittent hypoxia reduces NO availability through superoxide anion destruction, without reducing its synthesis, while continuous hypoxia affects both, producing larger nitrosative damage which could be related to the more severe cardiovascular alterations. PMID:24719876

  6. Superoxide and Singlet Oxygen Produced within the Thylakoid Membranes Both Cause Photosystem I Photoinhibition1[OPEN

    PubMed Central

    Takumi, Shigeo; Hashiguchi, Masaki; Sejima, Takehiro

    2016-01-01

    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 (1O2) is involved in PSI photoinhibition induced by rSP treatment. From these results, we suggest that PSI photoinhibition is caused by both O2− and 1O2 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. PMID:26936894

  7. Structure and gene expression of the E. coli Mn-superoxide dismutase gene.

    PubMed

    Takeda, Y; Avila, H

    1986-06-11

    Superoxide dismutase is an enzyme which converts superoxide O2- to hydrogen peroxide. Using a single synthetic oligonucleotide 33mer, we screened the E. coli DNA library and isolated a clone containing the E. coli manganese-superoxide dismutase gene. We determined the DNA sequence. The analysis of the DNA sequence and in vivo as well as in vitro transcription has shown the following. The DNA sequence suggests two possible promoters. However, only one of them seems active during normal aerobic growth. Purified RNA polymerase initiates in vitro transcription from the same promoter. It is not clear whether the second promoter is functional. It is possible that this promoter could be activated under different growth conditions. There is an inverted repeat sequence which could form a stem-loop structure downstream of the translation stop codon TAA of the Mn-SOD gene. The results of the analysis of in vivo and in vitro RNA have shown that this is the transcription termination signal. Thus, the Mn-SOD gene constitutes a single gene operon. There is an almost perfect 19 base palindrome at the -35 region. The position and the size of the palindrome suggest that this could be a regulatory site.

  8. Vascular nitric oxide and superoxide anion contribute to sex-specific programmed cardiovascular physiology in mice

    PubMed Central

    Roghair, Robert D.; Segar, Jeffrey L.; Volk, Kenneth A.; Chapleau, Mark W.; Dallas, Lindsay M.; Sorenson, Anna R.; Scholz, Thomas D.; Lamb, Fred S.

    2009-01-01

    Intrauterine environmental pertubations have been linked to the development of adult hypertension. We sought to evaluate the interrelated roles of sex, nitric oxide, and reactive oxygen species (ROS) in programmed cardiovascular disease. Programming was induced in mice by maternal dietary intervention (DI; partial substitution of protein with carbohydrates and fat) or carbenoxolone administration (CX, to increase fetal glucocorticoid exposure). Adult blood pressure and locomotor activity were recorded by radiotelemetry at baseline, after a week of high salt, and after a week of high salt plus nitric oxide synthase inhibition (by l-NAME). In male offspring, DI or CX programmed an elevation in blood pressure that was exacerbated by Nω-nitro-l-arginine methyl ester administration, but not high salt alone. Mesenteric resistance vessels from DI male offspring displayed impaired vasorelaxation to ACh and nitroprusside, which was blocked by catalase and superoxide dismutase. CX-exposed females were normotensive, while DI females had nitric oxide synthase-dependent hypotension and enhanced mesenteric dilation. Despite the disparate cardiovascular phenotypes, both male and female DI offspring displayed increases in locomotor activity and aortic superoxide production. Despite dissimilar blood pressures, DI and CX-exposed females had reductions in cardiac baroreflex sensitivity. In conclusion, both maternal malnutrition and fetal glucocorticoid exposure program increases in arterial pressure in male but not female offspring. While maternal DI increased both superoxide-mediated vasoconstriction and nitric oxide mediated vasodilation, the balance of these factors favored the development of hypertension in males and hypotension in females. PMID:19144750

  9. Vascular nitric oxide and superoxide anion contribute to sex-specific programmed cardiovascular physiology in mice.

    PubMed

    Roghair, Robert D; Segar, Jeffrey L; Volk, Kenneth A; Chapleau, Mark W; Dallas, Lindsay M; Sorenson, Anna R; Scholz, Thomas D; Lamb, Fred S

    2009-03-01

    Intrauterine environmental pertubations have been linked to the development of adult hypertension. We sought to evaluate the interrelated roles of sex, nitric oxide, and reactive oxygen species (ROS) in programmed cardiovascular disease. Programming was induced in mice by maternal dietary intervention (DI; partial substitution of protein with carbohydrates and fat) or carbenoxolone administration (CX, to increase fetal glucocorticoid exposure). Adult blood pressure and locomotor activity were recorded by radiotelemetry at baseline, after a week of high salt, and after a week of high salt plus nitric oxide synthase inhibition (by l-NAME). In male offspring, DI or CX programmed an elevation in blood pressure that was exacerbated by N(omega)-nitro-l-arginine methyl ester administration, but not high salt alone. Mesenteric resistance vessels from DI male offspring displayed impaired vasorelaxation to ACh and nitroprusside, which was blocked by catalase and superoxide dismutase. CX-exposed females were normotensive, while DI females had nitric oxide synthase-dependent hypotension and enhanced mesenteric dilation. Despite the disparate cardiovascular phenotypes, both male and female DI offspring displayed increases in locomotor activity and aortic superoxide production. Despite dissimilar blood pressures, DI and CX-exposed females had reductions in cardiac baroreflex sensitivity. In conclusion, both maternal malnutrition and fetal glucocorticoid exposure program increases in arterial pressure in male but not female offspring. While maternal DI increased both superoxide-mediated vasoconstriction and nitric oxide mediated vasodilation, the balance of these factors favored the development of hypertension in males and hypotension in females.

  10. Cloning, Purification, and Characterization of Recombinant Human Extracellular Superoxide Dismutase in SF9 Insect Cells

    PubMed Central

    Shrestha, Pravesh; Yun, Ji-Hye; Kim, Woo Taek; Kim, Tae-Yoon; Lee, Weontae

    2016-01-01

    A balance between production and degradation of reactive oxygen species (ROS) is critical for maintaining cellular homeostasis. Increased levels of ROS during oxidative stress are associated with disease conditions. Antioxidant enzymes, such as extracellular superoxide dismutase (EC-SOD), in the extracellular matrix (ECM) neutralize the toxicity of superoxide. Recent studies have emphasized the importance of EC-SOD in protecting the brain, lungs, and other tissues from oxidative stress. Therefore, EC-SOD would be an excellent therapeutic drug for treatment of diseases caused by oxidative stress. We cloned both the full length (residues 1–240) and truncated (residues 19–240) forms of human EC-SOD (hEC-SOD) into the donor plasmid pFastBacHTb. After transposition, the bacmid was transfected into the Sf9-baculovirus expression system and the expressed hEC-SOD purified using FLAG-tag. Western blot analysis revealed that hEC-SOD is present both as a monomer (33 kDa) and a dimer (66 kDa), as detected by the FLAG antibody. A water-soluble tetrazolium (WST-1) assay showed that both full length and truncated hEC-SOD proteins were enzymatically active. We showed that a potent superoxide dismutase inhibitor, diethyldithiocarbamate (DDC), inhibits hEC-SOD activity. PMID:26912083

  11. Superoxide dismutase, catalase, and. alpha. -tocopherol content of stored potato tubers. [Solanum tuberosum L

    SciTech Connect

    Spychalla, J.P.; Desborough, S.L. )

    1990-11-01

    Activated oxygen or oxygen free radical mediated damage to plants has been established or implicated in many plant stress situations. The extent of activated oxygen damage to potato (Solanum tuberosum L.) tubers during low temperature storage and long-term storage is not known. Quantitation of oxygen free radical mediated damage in plant tissues is difficult. However, it is comparatively easy to quantitate endogenous antioxidants, which detoxify potentially damaging forms of activated oxygen. Three tuber antioxidants, superoxide dismutase, catalase, and {alpha}-tocopherol were assayed from four potato cultivars stored at 3{degree}C and 9{degree}C for 40 weeks. Tubers stored at 3{degree}C demonstrated increased superoxide dismutase activities (up to 72%) compared to tubers stored at 9{degree}C. Time dependent increases in the levels of superoxide dismutase, catalase, and {alpha}-tocopherol occurred during the course of the 40 week storage. The possible relationship between these increases in antioxidants and the rate of activated oxygen production in the tubers is discussed.

  12. The Basic Understanding of Lithium Superoxide in Li-O2 Battery

    NASA Astrophysics Data System (ADS)

    Lau, Kah Chun; Zhai, Dengyun; Wang, Hsien-Hau; Luo, Xiangyi; Wen, Jianguo; Miller, Dean; Redfern, Paul; Lu, Jun; Curtiss, Larry; Amine, Khalil

    The electrochemical and chemical processes that involved in Li-O2 battery are complex, and depend heavily on electrode materials, electrolytes, interfaces, and cell operating conditions. In non-aqueous Li-O2 battery, the main discharge products are commonly known to be lithium peroxide (Li2O2) , and possibly some other parasitic components (i.e. Li2CO3, LiOH, Li2O). However, the superoxide intermediates and lithium superoxide (O2-, LiO2) which are commonly known to be metastable can also be found as reported. Relative to these compounds (i.e. Li2CO3, Li2O,LiOH,Li2O2) in discharge products, little is known about LiO2. To have a basic understanding of lithium superoxide, both theoretical studies and experimental characterizations are important. In this presentation, the recent developments, studies and findings of this exotic species will be discussed. This work was primarily supported by the U.S. Department of Energy under Contract DE-AC02-06CH11357 from the Vehicle Technologies Office, Department of Energy, Office of Energy Efficiency and Renewable Energy.

  13. 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. PMID:14651968

  14. Chlorovirus PBCV-1 Encodes an Active Copper-Zinc Superoxide Dismutase

    PubMed Central

    Kang, Ming; Duncan, Garry A.; Kuszynski, Charles; Oyler, George; Zheng, Jiayin; Becker, Donald F.

    2014-01-01

    ABSTRACT Superoxide dismutases (SODs) are metalloproteins that protect organisms from toxic reactive oxygen species by catalyzing the conversion of superoxide anion to hydrogen peroxide and molecular oxygen. Chlorovirus PBCV-1 encodes a 187-amino-acid protein that resembles a Cu-Zn SOD with all of the conserved amino acid residues for binding copper and zinc (named cvSOD). cvSOD has an internal Met that results in a 165-amino-acid protein (named tcvSOD). Both cvSOD and tcvSOD recombinant proteins inhibited nitroblue tetrazolium reduction of superoxide anion generated in a xanthine-xanthine oxidase system in solution. tcvSOD was chosen for further characterization because it was easier to produce. Recombinant tcvSOD also inhibited a riboflavin photochemical reduction system in a polyacrylamide gel assay, which was blocked by the Cu-Zn SOD inhibitor cyanide but not by azide, which inhibits Fe and Mn SODs. A kcat/Km value for cvSOD was determined by stop-flow spectrophotometry as 1.28 × 108 M−1 s−1, suggesting that cvSOD-catalyzed O2− dismutation was not a diffusion controlled encounter. The cvsod gene was expressed as a late gene, and cvSOD activity was detected in purified virions. Superoxide accumulated rapidly during virus infection, and circumstantial evidence indicates that cvSOD aids its decomposition to benefit virus replication. Cu-Zn SOD homologs have been described to occur in 3 other families of large DNA viruses, poxviruses, baculoviruses, and mimiviruses, which group as a clade. Interestingly, cvSOD does not group in the same clade as the other virus SODs but instead groups in an expanded clade that includes Cu-Zn SODs from many cellular organisms. IMPORTANCE Virus infection often leads to an increase in toxic reactive oxygen species in the host, which can be detrimental to virus replication. Viruses have developed various ways to overcome this barrier. As reported in this article, the chloroviruses often encode and package a functional Cu

  15. Activation of Mitochondrial Uncoupling Protein 4 and ATP-Sensitive Potassium Channel Cumulatively Decreases Superoxide Production in Insect Mitochondria.

    PubMed

    Slocińska, Malgorzata; Rosinski, Grzegorz; Jarmuszkiewicz, Wieslawa

    2016-01-01

    It has been evidenced that mitochondrial uncoupling protein 4 (UCP4) and ATP-regulated potassium channel (mKATP channel) of insect Gromphadorhina coqereliana mitochondria decrease superoxide anion production. We elucidated whether the two energy-dissipating systems work together on a modulation of superoxide level in cockroach mitochondria. Our data show that the simultaneous activation of UCP4 by palmitic acid and mKATP channel by pinacidil revealed a cumulative effect on weakening mitochondrial superoxide formation. The inhibition of UCP4 by GTP (and/or ATP) and mKATP channel by ATP elevated superoxide production. These results suggest a functional cooperation of both energy-dissipating systems in protection against oxidative stress in insects.

  16. Understanding how the thiolate sulfur contributes to the function of the non-heme iron enzyme superoxide reductase.

    PubMed

    Kovacs, Julie A; Brines, Lisa M

    2007-07-01

    Toxic superoxide radicals, generated via adventitious reduction of dioxygen, have been implicated in a number of disease states. The cysteinate-ligated non-heme iron enzyme superoxide reductase (SOR) degrades superoxide via reduction. Biomimetic analogues which provide insight into why nature utilizes a trans-thiolate to promote SOR function are described. Spectroscopic and/or structural characterization of the first examples of thiolate-ligated Fe (III)-peroxo complexes provides important benchmark parameters for the identification of biological intermediates. Oxidative addition of superoxide is favored by low redox potentials. The trans influence of the thiolate appears to significantly weaken the Fe-O peroxo bond, favoring proton-induced release of H 2O 2 from a high-spin Fe(III)-OOH complex. PMID:17536780

  17. High-Content Imaging Assays for Identifying Compounds that Generate Superoxide and Impair Mitochondrial Membrane Potential in Adherent Eukaryotic Cells.

    PubMed

    Billis, Puja; Will, Yvonne; Nadanaciva, Sashi

    2014-01-01

    Reactive oxygen species (ROS) are constantly produced in cells as a result of aerobic metabolism. When there is an excessive production of ROS and the cell's antioxidant defenses are overwhelmed, oxidative stress occurs. The superoxide anion is a type of ROS that is produced primarily in mitochondria but is also generated in other regions of the cell including peroxisomes, endoplasmic reticulum, plasma membrane, and cytosol. Here, a high-content imaging assay using the dye dihydroethidium is described for identifying compounds that generate superoxide in eukaryotic cells. A high-content imaging assay using the fluorescent dye tetramethylrhodamine methyl ester is also described to identify compounds that impair mitochondrial membrane potential in eukaryotic cells. The purpose of performing both assays is to identify compounds that (1) generate superoxide at lower concentrations than they impair mitochondrial membrane potential, (2) impair mitochondrial membrane potential at lower concentrations than they generate superoxide, (3) generate superoxide and impair mitochondrial function at similar concentrations, and (4) do not generate superoxide or impair mitochondrial membrane potential during the duration of the assays.

  18. The essential requirement for superoxide radical and nitric oxide formation for normal physiological function and healthy aging.

    PubMed

    Linnane, Anthony W; Kios, Michael; Vitetta, Luis

    2007-01-01

    Contrary to the dogma that superoxide anion and hydrogen peroxide formation are highly deleterious to cell function and healthy aging, we suggest this premise is flawed. Superoxide anion and hydrogen peroxide formation are essential to normal cellular function; they constitute a second messenger system absolutely required for the regulation of the metabolome. Embraced within this regulation is the modulation of cellular redox poise, bioenergy output, gene expression and cell differentiation. A key component in the overall process is coenzyme Q10 whose prooxidant function through the formation of superoxide anion and hydrogen peroxide is a major factor in the overall processes. The free radical gas, nitric oxide (similarly to superoxide anion), functions in the regulation of a wide range of cell systems. As part of the normal physiological process, superoxide anion and NO function separately and interactively as second messengers. Superoxide anion and nitric oxide play an intrinsic role in the regulated ordered turnover of proteins, rather than randomly cause protein damage and their inactivation. The proposition that metabolic free radical formation is unequivocally deleterious to cell function is rebutted; their toxicity as primary effectors in the aging process has been overemphasized. The concept that a dietary supplement of high concentrations of small-molecule antioxidants is a prophylactic/amelioration therapy for the aging process and age-associated diseases is questioned as to its clinical validity.

  19. Predicted effects of nitric oxide and superoxide on the vasoactivity of the afferent arteriole.

    PubMed

    Layton, Anita T; Edwards, Aurélie

    2015-10-15

    We expanded a published mathematical model of an afferent arteriole smooth muscle cell in rat kidney (Edwards A, Layton, AT. Am J Physiol Renal Physiol 306: F34-F48, 2014) to understand how nitric oxide (NO) and superoxide (O(2)(-)) modulate the arteriolar diameter and its myogenic response. The present model includes the kinetics of NO and O(2)(-) formation, diffusion, and reaction. Also included are the effects of NO and its second messenger cGMP on cellular Ca²⁺ uptake and efflux, Ca²⁺-activated K⁺ currents, and myosin light chain phosphatase activity. The model considers as well pressure-induced increases in O(2)(-) production, O(2)(-)-mediated regulation of L-type Ca²⁺ channel conductance, and increased O(2)(-) production in spontaneous hypertensive rats (SHR). Our results indicate that elevated O(2)(-) production in SHR is sufficient to account for observed differences between normotensive and hypertensive rats in the response of the afferent arteriole to NO synthase inhibition, Tempol, and angiotensin II at baseline perfusion pressures. In vitro, whether the myogenic response is stronger in SHR remains uncertain. Our model predicts that if mechanosensitive cation channels are not modulated by O(2)(-), then fractional changes in diameter induced by pressure elevations should be smaller in SHR than in normotensive rats. Our results also suggest that most NO diffuses out of the smooth muscle cell without being consumed, whereas most O(2)(-) is scavenged, by NO and superoxide dismutase. Moreover, the predicted effects of superoxide on arteriolar constriction are not predominantly due to its scavenging of NO. PMID:26180238

  20. Synthetic analogues of nickel superoxide dismutase: a new role for nickel in biology.

    PubMed

    Broering, Ellen P; Truong, Phan T; Gale, Eric M; Harrop, Todd C

    2013-01-01

    Nickel-containing superoxide dismutases (NiSODs) represent a novel approach to the detoxification of superoxide in biology and thus contribute to the biodiversity of mechanisms for the removal of reactive oxygen species (ROS). While Ni ions play critical roles in anaerobic microbial redox (hydrogenases and CO dehydrogenase/acetyl coenzyme A synthase), they have never been associated with oxygen metabolism. Several SODs have been characterized from numerous sources and are classified by their catalytic metal as Cu/ZnSOD, MnSOD, or FeSOD. Whereas aqueous solutions of Cu(II), Mn(II), and Fe(II) ions are capable of catalyzing the dismutation of superoxide, solutions of Ni(II) are not. Nonetheless, NiSOD catalyzes the reaction at the diffusion-controlled limit (~10(9) M(-1) s(-1)). To do this, nature has created a Ni coordination unit with the appropriate Ni(III/II) redox potential (~0.090 V vs Ag/AgCl). This potential is achieved by a unique ligand set comprised of residues from the N-terminus of the protein: Cys2 and Cys6 thiolates, the amino terminus and imidazole side chain of His1, and a peptide N-donor from Cys2. Over the past several years, synthetic modeling efforts by several groups have provided insight into understanding the intrinsic properties of this unusual Ni coordination site. Such analogues have revealed information regarding the (i) electrochemical properties that support Ni-based redox, (ii) oxidative protection and/or stability of the coordinated CysS ligands, (iii) probable H(+) sources for H(2)O(2) formation, and (iv) nature of the Ni coordination geometry throughout catalysis. This review includes the results and implications of such biomimetic work as it pertains to the structure and function of NiSOD.

  1. The effect of superoxide dismutase mimetic and catalase on the quality of postthawed goat semen.

    PubMed

    Shafiei, Mojtaba; Forouzanfar, Mohsen; Hosseini, Sayyed Morteza; Esfahani, Mohammad Hossein Nasr

    2015-05-01

    Manganese(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin chloride (MnTE) is a cell-permeable superoxide dismutase mimetic agent which can convert superoxide to hydrogen peroxide (H2O2). Supplementation of MnTE to a commercial semen extender can protect sperm from superoxide but not H2O2. Therefore, we proposed that addition of catalase (0.0, 200, or 400 IU/mL) in combination with MnTE (0.1 μM) may further improve the cryopreservation efficiency of goat semen in commercially optimized freezing media such as Andromed. Therefore, ejaculates were obtained from three adult bucks twice a week during the breeding season and diluted with Andromed supplemented with or without MnTE and catalase and were frozen in liquid nitrogen. Sperm parameters and reactive oxygen species contents were evaluated 2 hours after dilution (before freezing) and after freezing/thawing. The results revealed that all the treatments significantly (P ≤ 0.05) improved sperm motility, viability, and membrane integrity after freezing and reduced reactive oxygen species content compared with the control group, but maximum improvement was obtained in MnTE + 400 IU/mL catalase. In addition, supplementation with these antioxidants significantly (P ≤ 0.05) increases the cleavage rate after IVF. In conclusion, the results of present study suggest that addition of antioxidant MnTE or catalase to commercial optimized media, such as Andromed, improves total motility, membrane integrity, and viability of goat semen samples after thawing. But the degree of improvement for these parameters significantly (P ≤ 0.05) higher when MnTE and catalase were simultaneously added to the cryopreservation media.

  2. Superoxide-dependent consumption of nitric oxide in biological media may confound in vitro experiments.

    PubMed

    Keynes, Robert G; Griffiths, Charmaine; Garthwaite, John

    2003-01-15

    NO functions ubiquitously as a biological messenger but has also been implicated in various pathologies, a role supported by many reports that exogenous or endogenous NO can kill cells in tissue culture. In the course of experiments aimed at examining the toxicity of exogenous NO towards cultured cells, we found that most of the NO delivered using a NONOate (diazeniumdiolate) donor was removed by reaction with the tissue-culture medium. Two NO-consuming ingredients were identified: Hepes buffer and, under laboratory lighting, the vitamin riboflavin. In each case, the loss of NO was reversed by the addition of superoxide dismutase. The effect of Hepes was observed over a range of NONOate concentrations (producing up to 1 microM NO). Furthermore, from measurements of soluble guanylate cyclase activity, Hepes-dependent NO consumption remained significant at the low nanomolar NO concentrations relevant to physiological NO signalling. The combination of Hepes and riboflavin (in the light) acted synergistically to the extent that, instead of a steady-state concentration of about 1 microM being generated, NO was undetectable (<10 nM). Again, the consumption could be inhibited by superoxide dismutase. A scheme is proposed whereby a "vicious cycle" of superoxide radical (O(2)(.-)) formation occurs as a result of oxidation of Hepes to its radical species, fuelled by the subsequent reaction of O(2)(.-) with NO to form peroxynitrite (ONOO(-)). The inadvertent production of ONOO(-) and other reactive species in biological media, or the associated loss of NO, may contribute to the adverse effects, or otherwise, of NO in vitro.

  3. Six-coordinate manganese(3+) in catalysis by yeast manganese superoxide dismutase

    PubMed Central

    Sheng, Yuewei; Butler Gralla, Edith; Schumacher, Mikhail; Cascio, Duilio; Cabelli, Diane E.; Selverstone Valentine, Joan

    2012-01-01

    Reduction of superoxide () 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 exclusively 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 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 Mn3+. We here propose and compare two hypothetical mechanisms for the mutant yeast enzyme, differing in the structure of the Mn-peroxo complex yet both involving formation of the active six-coordinate Mn3+ 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 Mn2+, six-coordinate Mn3+ species could also actively function in the mechanism of WT yeast MnSODs. PMID:22908245

  4. Structures of the superoxide reductase from Pyrococcus furiosus in the oxidized and reduced states.

    PubMed

    Yeh, A P; Hu, Y; Jenney, F E; Adams, M W; Rees, D C

    2000-03-14

    Superoxide reductase (SOR) is a blue non-heme iron protein that functions in anaerobic microbes as a defense mechanism against reactive oxygen species by catalyzing the reduction of superoxide to hydrogen peroxide [Jenney, F. E., Jr., Verhagen, M. F. J. M., Cui, X. , and Adams, M. W. W. (1999) Science 286, 306-309]. Crystal structures of SOR from the hyperthermophilic archaeon Pyrococcus furiosus have been determined in the oxidized and reduced forms to resolutions of 1.7 and 2.0 A, respectively. SOR forms a homotetramer, with each subunit adopting an immunoglobulin-like beta-barrel fold that coordinates a mononuclear, non-heme iron center. The protein fold and metal center are similar to those observed previously for the homologous protein desulfoferrodoxin from Desulfovibrio desulfuricans [Coelho, A. V., Matias, P., Fülöp, V., Thompson, A., Gonzalez, A., and Carrondo, M. A. (1997) J. Bioinorg. Chem. 2, 680-689]. Each iron is coordinated to imidazole nitrogens of four histidines in a planar arrangement, with a cysteine ligand occupying an axial position normal to this plane. In two of the subunits of the oxidized structure, a glutamate carboxylate serves as the sixth ligand to form an overall six-coordinate, octahedral coordinate environment. In the remaining two subunits, the sixth coordination site is either vacant or occupied by solvent molecules. The iron centers in all four subunits of the reduced structure exhibit pentacoordination. The structures of the oxidized and reduced forms of SOR suggest a mechanism by which superoxide accessibility may be controlled and define a possible binding site for rubredoxin, the likely physiological electron donor to SOR. PMID:10704199

  5. Predicted effects of nitric oxide and superoxide on the vasoactivity of the afferent arteriole.

    PubMed

    Layton, Anita T; Edwards, Aurélie

    2015-10-15

    We expanded a published mathematical model of an afferent arteriole smooth muscle cell in rat kidney (Edwards A, Layton, AT. Am J Physiol Renal Physiol 306: F34-F48, 2014) to understand how nitric oxide (NO) and superoxide (O(2)(-)) modulate the arteriolar diameter and its myogenic response. The present model includes the kinetics of NO and O(2)(-) formation, diffusion, and reaction. Also included are the effects of NO and its second messenger cGMP on cellular Ca²⁺ uptake and efflux, Ca²⁺-activated K⁺ currents, and myosin light chain phosphatase activity. The model considers as well pressure-induced increases in O(2)(-) production, O(2)(-)-mediated regulation of L-type Ca²⁺ channel conductance, and increased O(2)(-) production in spontaneous hypertensive rats (SHR). Our results indicate that elevated O(2)(-) production in SHR is sufficient to account for observed differences between normotensive and hypertensive rats in the response of the afferent arteriole to NO synthase inhibition, Tempol, and angiotensin II at baseline perfusion pressures. In vitro, whether the myogenic response is stronger in SHR remains uncertain. Our model predicts that if mechanosensitive cation channels are not modulated by O(2)(-), then fractional changes in diameter induced by pressure elevations should be smaller in SHR than in normotensive rats. Our results also suggest that most NO diffuses out of the smooth muscle cell without being consumed, whereas most O(2)(-) is scavenged, by NO and superoxide dismutase. Moreover, the predicted effects of superoxide on arteriolar constriction are not predominantly due to its scavenging of NO.

  6. Macrophage Stimulating Protein (MSP) evokes superoxide anion production by human macrophages of different origin

    PubMed Central

    Brunelleschi, Sandra; Penengo, Lorenza; Lavagno, Luisa; Santoro, Claudio; Colangelo, Donato; Viano, Ilario; Gaudino, Giovanni

    2001-01-01

    Macrophage Stimulating Protein (MSP), a serum factor related to Hepatocyte Growth Factor, was originally discovered to stimulate chemotaxis of murine resident peritoneal macrophages. MSP is the ligand for Ron, a member of the Met subfamily of tyrosine kinase receptors. The effects of MSP on human macrophages and the role played in human pathophysiology have long been elusive.We show here that human recombinant MSP (hrMSP) evokes a dose-dependent superoxide anion production in human alveolar and peritoneal macrophages as well as in monocyte-derived macrophages, but not in circulating human monocytes. Consistently, the mature Ron protein is expressed by the MSP responsive cells but not by the unresponsive monocytes. The respiratory burst evoked by hrMSP is quantitatively higher than the one induced by N-formylmethionyl-leucyl-phenylalanine and similar to phorbol myristate acetate-evoked one.To investigate the mechanisms involved in NADPH oxidase activation, leading to superoxide anion production, different signal transduction inhibitors were used. By using the non selective tyrosine kinase inhibitor genistein, the selective c-Src inhibitor PP1, the tyrosine phosphatase inhibitor sodium orthovanadate, the phosphatidylinositol 3-kinase inhibitor wortmannin, the p38 inhibitor SB203580, the MEK inhibitor PD098059, we demonstrate that hrMSP-evoked superoxide production is mediated by tyrosine kinase activity, requires the activation of Src but not of PI 3-kinase. We also show that MAP kinase and p38 signalling pathways are involved.These results clearly indicate that hrMSP induces the respiratory burst in human macrophages but not in monocytes, suggesting for the MSP/Ron complex a role of activator as well as of possible marker for human mature macrophages. PMID:11704649

  7. Six-coordinate manganese(3+) in catalysis by yeast manganese superoxide dismutase

    SciTech Connect

    Sheng, Yuewei; Gralla, Edith Butler; Schumacher, Mikhail; Cascio, Duilio; Cabelli, Diane E.; Valentine, Joan Selverstone

    2012-10-10

    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 exclusively 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.

  8. The effect of superoxide dismutase mimetic and catalase on the quality of postthawed goat semen.

    PubMed

    Shafiei, Mojtaba; Forouzanfar, Mohsen; Hosseini, Sayyed Morteza; Esfahani, Mohammad Hossein Nasr

    2015-05-01

    Manganese(III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin chloride (MnTE) is a cell-permeable superoxide dismutase mimetic agent which can convert superoxide to hydrogen peroxide (H2O2). Supplementation of MnTE to a commercial semen extender can protect sperm from superoxide but not H2O2. Therefore, we proposed that addition of catalase (0.0, 200, or 400 IU/mL) in combination with MnTE (0.1 μM) may further improve the cryopreservation efficiency of goat semen in commercially optimized freezing media such as Andromed. Therefore, ejaculates were obtained from three adult bucks twice a week during the breeding season and diluted with Andromed supplemented with or without MnTE and catalase and were frozen in liquid nitrogen. Sperm parameters and reactive oxygen species contents were evaluated 2 hours after dilution (before freezing) and after freezing/thawing. The results revealed that all the treatments significantly (P ≤ 0.05) improved sperm motility, viability, and membrane integrity after freezing and reduced reactive oxygen species content compared with the control group, but maximum improvement was obtained in MnTE + 400 IU/mL catalase. In addition, supplementation with these antioxidants significantly (P ≤ 0.05) increases the cleavage rate after IVF. In conclusion, the results of present study suggest that addition of antioxidant MnTE or catalase to commercial optimized media, such as Andromed, improves total motility, membrane integrity, and viability of goat semen samples after thawing. But the degree of improvement for these parameters significantly (P ≤ 0.05) higher when MnTE and catalase were simultaneously added to the cryopreservation media. PMID:25698161

  9. Limitation of dietary copper and zinc decreases superoxide dismutase activity in the onion fly, Delia antiqua.

    PubMed

    Matsuo, T; Ooe, S; Ishikawa, Y

    1997-06-01

    Larvae of the onion fly, Delia antiqua, have lower superoxide dismutase (SOD) activity when they are fed a defined synthetic diet that contains no copper or zinc. SOD activity was rapidly recovered when these larvae were fed onion bulbs. Addition of copper and zinc to the synthetic diet also led to the recovery of SOD activity. Results of an immunoblotting analysis using anti-D. antiqua CuZnSOD mouse monoclonal antibody suggest that this alteration of SOD activity is dependent on the amount of CuZnSOD. PMID:9172377

  10. 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.

  11. Protection against hyperoxia by serum from endotoxin treated rats: absence of superoxide dismutase induction

    SciTech Connect

    Berg, J.T.; Smith, R.M.

    1988-01-01

    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 that a serum factor may be involved.

  12. Formation and disappearance of superoxide radicals in aqueous solutions. [79 references

    SciTech Connect

    Allen, A O; Bielski, B H.J.

    1980-01-01

    A literature review of superoxide radicals in aqueous solutions is presented covering the following: history; methods of formation of aqueous HO/sub 2//HO/sub 2//sup -/ by radiolysis and photolysis, electrolysis, mixing nonaqueous solutions into water, chemical reactions, enzymatic generation of O/sub 2//sup -/, and photosensitization; and properties of HO/sub 2//O/sub 2//sup -/ in aqueous solution, which cover spontaneous dismutation rates, pk and absorption spectra, catalyzed dismutation, thermodynamics and the so-called Haber-Weiss Reaction.

  13. 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.-).

  14. 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

  15. Loss of NOX-Derived Superoxide Exacerbates Diabetogenic CD4 T-Cell Effector Responses in Type 1 Diabetes.

    PubMed

    Padgett, Lindsey E; Anderson, Brian; Liu, Chao; Ganini, Douglas; Mason, Ronald P; Piganelli, Jon D; Mathews, Clayton E; Tse, Hubert M

    2015-12-01

    Reactive oxygen species (ROS) play prominent roles in numerous biological systems. While classically expressed by neutrophils and macrophages, CD4 T cells also express NADPH oxidase (NOX), the superoxide-generating multisubunit enzyme. Our laboratory recently demonstrated that superoxide-deficient nonobese diabetic (NOD.Ncf1(m1J)) mice exhibited a delay in type 1 diabetes (T1D) partially due to blunted IFN-γ synthesis by CD4 T cells. For further investigation of the roles of superoxide on CD4 T-cell diabetogenicity, the NOD.BDC-2.5.Ncf1(m1J) (BDC-2.5.Ncf1(m1J)) mouse strain was generated, possessing autoreactive CD4 T cells deficient in NOX-derived superoxide. Unlike NOD.Ncf1(m1J), stimulated BDC-2.5.Ncf1(m1J) CD4 T cells and splenocytes displayed elevated synthesis of Th1 cytokines and chemokines. Superoxide-deficient BDC-2.5 mice developed spontaneous T1D, and CD4 T cells were more diabetogenic upon adoptive transfer into NOD.Rag recipients due to a skewing toward impaired Treg suppression. Exogenous superoxide blunted exacerbated Th1 cytokines and proinflammatory chemokines to approximately wild-type levels, concomitant with reduced IL-12Rβ2 signaling and P-STAT4 (Y693) activation. These results highlight the importance of NOX-derived superoxide in curbing autoreactivity due, in part, to control of Treg function and as a redox-dependent checkpoint of effector T-cell responses. Ultimately, our studies reveal the complexities of free radicals in CD4 T-cell responses.

  16. 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

    2016-09-01

    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. PMID:27498623

  17. Effects of salinity change on two superoxide dismutases (SODs) in juvenile marbled eel Anguilla marmorata.

    PubMed

    Wang, Li; Wang, Xiaolu; Yin, Shaowu

    2016-01-01

    Salinity is one of the most important factors that affect the fish growth and survival. Superoxide dismutases (SODs), as the primary antioxidant enzymes, play a first role in the process of preventing oxidative stress caused by excessive superoxide anion (O[Formula: see text]) in living organisms. In the present study, we investigated the effects of salinity on the gene expressions as well as enzymatic activities of MnSOD and Cu/ZnSOD in gill, intestine, kidney, liver and muscle tissues of the marbled eel Anguilla marmorata. We found that the liver might possess stronger redox capacity compared with other tissues. Furthermore, the gene expressions and enzymatic activities of SODs in juvenile marbled eels could be effectively enhanced by low salinity but inhibited when the salinity was higher than the body tolerance. Our findings indicated that MnSOD and Cu/ZnSOD played vital roles in the adaptation of marbled eels to salinity variation, which contributed to the elucidation of physiological adaptation and regulatory mechanism of SODs in eels. PMID:27547518

  18. Exogenous Superoxide Dismutase: Action on Liver Oxidative Stress in Animals with Streptozotocin-Induced Diabetes

    PubMed Central

    Di Naso, Fábio Cangeri; Simões Dias, Alexandre; Porawski, Marilene; Marroni, Norma Anair Possa

    2011-01-01

    Aim. To investigate the effects of exogenous antioxidant copper zinc superoxide dismutase (Cu/Zn SOD) on oxidative stress in the experimental model of diabetes mellitus (DM). Methods. Twenty eight male Wistar rats divided in four groups were used: control (CO), controls treated with SOD (CO + SOD), diabetics (DM), and diabetics treated with SOD (DM + SOD). SOD (orgotein, 13 mg/Kg body weight was administered. DM was induced by a single streptozotocin injection (i.p., 70 mg/kg), and 60 days later, we evaluated liver oxidative stress. Results. Liver lipoperoxidation was increased in the DM group and significantly decreased in the DM + SOD group. Nitrite and nitrate measures were reduced in the DM and increased in the DM + SOD group, while iNOS expression in the DM group was 32% greater than in the CO and 53% greater in the DM + SOD group than in the DM group (P < .01). P65 expression was 37% higher in the DM (P < .05), and there was no significant difference between the DM and DM + SOD groups. Conclusion. SOD treatment reduced liver oxidative stress in diabetic animals, even though it did not change NFκB. SOD also increased NO, probably by the increased dismutation of the superoxide radical. The iNOS expression increase, which became even more evident after SOD administration. PMID:21437212

  19. Diversity, Function and Evolution of Genes Coding for Putative Ni-Containing Superoxide Dismutases

    SciTech Connect

    Dupont,C.; Neupane, K.; Shearer, J.; Palenik, B.

    2008-01-01

    We examined the phylogenetic distribution, functionality and evolution of the sodN gene family, which has been shown to code for a unique Ni-containing isoform of superoxide dismutase (Ni-SOD) in Streptomyces. Many of the putative sodN sequences retrieved from public domain genomic and metagenomic databases are quite divergent from structurally and functionally characterized Ni-SOD. Structural bioinformatics studies verified that the divergent members of the sodN protein family code for similar three-dimensional structures and identified evolutionarily conserved amino acid residues. Structural and biochemical studies of the N-terminus 'Ni-hook' motif coded for by the putative sodN sequences confirmed both Ni (II) ligating and superoxide dismutase activity. Both environmental and organismal genomes expanded the previously noted phylogenetic distribution of sodN, and the sequences form four well-separated clusters, with multiple subclusters. The phylogenetic distribution of sodN suggests that the gene has been acquired via horizontal gene transfer by numerous organisms of diverse phylogenetic background, including both Eukaryotes and Prokaryotes. The presence of sodN correlates with the genomic absence of the gene coding for Fe-SOD, a structurally and evolutionarily distinct isoform of SOD. Given the low levels of Fe found in the marine environment from where many sequences were attained, we suggest that the replacement of Fe-SOD with Ni-SOD may be an evolutionary adaptation to reduce iron requirements.

  20. Mitochondrial superoxide production contributes to vancomycin-induced renal tubular cell apoptosis.

    PubMed

    Arimura, Yohei; Yano, Takahisa; Hirano, Megumi; Sakamoto, Yuya; Egashira, Nobuaki; Oishi, Ryozo

    2012-05-01

    Vancomycin chloride (VCM), a glycopeptide antibiotic, is widely used for the therapy of infections caused by methicillin-resistant Staphylococcus aureus. However, nephrotoxicity is a major adverse effect in VCM therapy. In this study, we investigated the cellular mechanisms underlying VCM-induced renal tubular cell injury in cultured LLC-PK1 cells. VCM induced a concentration- and time-dependent cell injury in LLC-PK1 cells. VCM caused increases in the numbers of annexin V-positive/PI-negative cells and TUNEL-positive cells, indicating the involvement of apoptotic cell death in VCM-induced renal cell injury. The VCM-induced apoptosis was accompanied by the activation of caspase-9 and caspase-3/7 and reversed by inhibitors of these caspases. Moreover, VCM caused an increase in intracellular reactive oxygen species production and mitochondrial membrane depolarization, which were reversed by vitamin E. In addition, mitochondrial complex I activity was inhibited by VCM as well as by the complex I inhibitor rotenone, and rotenone mimicked the VCM-induced LLC-PK1 cell injury. These findings suggest that VCM causes apoptotic cell death in LLC-PK1 cells by enhancing mitochondrial superoxide production leading to mitochondrial membrane depolarization followed by the caspase activities. Moreover, mitochondrial complex I may play an important role in superoxide production and renal tubular cell apoptosis induced by VCM.

  1. 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.

  2. Xanthine oxidase-mediated denitrosation of N-nitroso-tryptophan by superoxide and uric acid.

    PubMed

    Viles, Kimberley; Mathai, Clinton; Jourd'heuil, Frances L; Jourd'heuil, David

    2013-01-15

    Recent studies indicate the formation of protein nitrosamines in vivo and tryptophan residues in proteins might represent important targets of nitrosative and oxidative stress. In the present work, we examined the mechanism by which xanthine oxidase (XO) denitrosates N-nitroso Trp residues and determined the applicability of the reactions involved to the detection of nitrosated Trp residues by tri-iodide-based chemiluminescence. We found that - in addition to superoxide - denitrosation of N-acetyl-nitroso Trp (NANT) by hypoxanthine and XO occurred via the intermediacy of uric acid. Zero-order dependence of NANT decay rate with uric acid was achieved with increasing concentrations of uric acid (k(0)∼6.0×10(-4)s(-1)) and generated nitric oxide. In contrast, S-nitrosoglutathione and nitrosyl-myoglobin were stable in the presence of uric acid. NANT decomposition by uric acid could be reproducibly measured using the tri-iodide-based chemiluminescence assay in the presence of excess nitrite upon pre-treatment with acidified sulfanilamide. N-nitrosated albumin was sensitive to uric acid-induced decomposition only after proteolytic degradation. In conclusion, XO decomposes nitrosated Trp through superoxide and uric acid pathways and in the case of uric acid generates free nitric oxide. Site-specificity of this reaction may possibly be used in combination with the tri-iodide-based chemiluminescence assay to discern between nitrosated Trp, S-nitrosothiols, and nitrosylated heme proteins. PMID:23099296

  3. Superoxide dismutase activity and gene expression levels in Saudi women with recurrent miscarriage

    PubMed Central

    GHNEIM, HAZEM K.; AL-SHEIKH, YAZEED A.; ALSHEBLY, MASHAEL M.; ABOUL-SOUD, MOURAD A. M.

    2016-01-01

    The antioxidant activities of superoxide dismutase 1 (SOD1) and SOD2, as well as the levels of the oxidant superoxide anion (SOA) and the micronutrients zinc (Zn), copper (Cu) and manganese (Mn), were assayed in plasma, whole blood and placental tissue of non-pregnant (NP), healthy pregnant (HP) women and recurrent miscarriage (RM) patients. The results showed that SOD1 and SOD2 activities and the levels of Zn, Cu and Mn in plasma and whole blood of HP women were slightly, but significantly lower, and even more significantly decreased in RM patients compared to those observed in NP women (P<0.05 and P<0.0001, respectively). Additionally, whereas plasma SOD1 and SOD2 activities and Zn, Cu and Mn levels were significantly lower in RM patients, those of whole blood and placental tissue were significantly lower when compared to HP women (P<0.001 and P<0.0001, respectively). Concurrently, there were consistent increases of equal magnitude and statistical significance in SOA levels in all the assayed samples as identified by a comparison between the subjects. The findings thus supported oxidative metabolism and excessive reactive oxygen species generation. The resultant oxidative stress, identified in whole blood and placental tissues of RM patients, may have been a primary cause of RM. Dietary supplementation of Zn, Cu and Mn may be beneficial to these patients pre- and post-conception. PMID:26821085

  4. Unique Characteristics of Recombinant Hybrid Manganese Superoxide Dismutase from Staphylococcus equorum and S. saprophyticus.

    PubMed

    Retnoningrum, Debbie S; Rahayu, Anis Puji; Mulyanti, Dina; Dita, Astrid; Valerius, Oliver; Ismaya, Wangsa T

    2016-04-01

    A recombinant hybrid of manganese dependent-superoxide dismutase of Staphylococcus equorum and S. saprophyticus has successfully been overexpressed in Escherichia coli BL21(DE3), purified, and characterized. The recombinant enzyme suffered from degradation and aggregation upon storage at -20 °C, but not at room temperature nor in cold. Chromatographic analysis in a size exclusion column suggested the occurrence of dimeric form, which has been reported to contribute in maintaining the stability of the enzyme. Effect of monovalent (Na(+), K(+)), divalent (Ca(2+), Mg(2+)), multivalent (Mn(2+/4+), Zn(2+/4+)) cations and anions (Cl(-), SO4 (2-)) to the enzyme stability or dimeric state depended on type of cation or anion, its concentration, and pH. However, tremendous effect was observed with 50 mM ZnSO4, in which thermostability of both the dimer and monomer was increased. Similar situation was not observed with MnSO4, and its presence was detrimental at 200 mM. Finally, chelating agent appeared to destabilize the dimer around neutral pH and dissociate it at basic pH. The monomer remained stable upon addition of ethylene diamine tetraacetic acid. Here we reported unique characteristics and stability of manganese dependent-superoxide dismutase from S. equorum/saprophyticus.

  5. Effects of salinity change on two superoxide dismutases (SODs) in juvenile marbled eel Anguilla marmorata.

    PubMed

    Wang, Li; Wang, Xiaolu; Yin, Shaowu

    2016-01-01

    Salinity is one of the most important factors that affect the fish growth and survival. Superoxide dismutases (SODs), as the primary antioxidant enzymes, play a first role in the process of preventing oxidative stress caused by excessive superoxide anion (O[Formula: see text]) in living organisms. In the present study, we investigated the effects of salinity on the gene expressions as well as enzymatic activities of MnSOD and Cu/ZnSOD in gill, intestine, kidney, liver and muscle tissues of the marbled eel Anguilla marmorata. We found that the liver might possess stronger redox capacity compared with other tissues. Furthermore, the gene expressions and enzymatic activities of SODs in juvenile marbled eels could be effectively enhanced by low salinity but inhibited when the salinity was higher than the body tolerance. Our findings indicated that MnSOD and Cu/ZnSOD played vital roles in the adaptation of marbled eels to salinity variation, which contributed to the elucidation of physiological adaptation and regulatory mechanism of SODs in eels.

  6. 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

  7. cap alpha. -Naphthylisothiocyanate (ANIT) stimulates the release of superoxide by rat neutrophils in vitro

    SciTech Connect

    Roth, R.A.; Hewett, J.

    1986-03-01

    ..cap alpha..-Naphthylisothiocyanate (ANIT) is an hepatotoxicant that produces cholestasis and hyperbilirubinemia in rats. Its mechanism of action is unknown. The observation that polymorphonuclear leukocytes (PMNs) accumulate in the bile ductular region of the liver following ANIT administration prompted us to examine the ability of ANIT to stimulate these cells. PMNs elicited from rat peritoneum were treated with ANIT in vitro to test for the release of superoxide anion (O/sub 2//sup -/). ANIT stimulated O/sub 2//sup -/ release from PMNs in a concentration-dependent manner. Maximal O/sub 2//sup -/ release was achieved by an ANIT concentration of 110 ..mu.. M. O/sub 2//sup -/ release was rapid after the first few minutes of ANIT addition and ceased entirely between 10 and 15 minutes. An increase in the extracellular activity of lactate dehydrogenase also occurred after a 5-10 minute lag phase following ANIT addition. PMNs exposed to ANIT also failed to exclude trypan blue dye, either in the presence or in the absence of superoxide dismutase and catalase, suggesting a direct, oxygen radical-independent, cytotoxic effect of ANIT on PMNs. Release of the lysosomal enzyme, ..beta..-glucuronidase, also occurred within 5 min following exposure of PMNs to ANIT. These results indicate that ANIT stimulates the release of cytotoxic agents from rat PMNs in vitro and suggests that the direct stimulation of PMNs in vivo may contribute to ANIT-induced hepatotoxicity in rats.

  8. Cigarette smoke extract contracts isolated porcine coronary arteries by superoxide anion-mediated degradation of EDRF.

    PubMed

    Murohara, T; Kugiyama, K; Ohgushi, M; Sugiyama, S; Yasue, H

    1994-03-01

    To test whether cigarette smoke extract (CSE) influences the endothelial regulation of vascular tone in vitro, pig coronary arterial rings were incubated in organ chambers and isometric tension changes were examined. CSE was prepared by bubbling mainstream smoke of one filter cigarette into phosphate-buffered saline (2 ml). Fresh CSE (3.3, 10, and 30 microliters/ml) elicited initial contraction and subsequent relaxation during stable contraction to prostaglandin F2 alpha (PGF2 alpha). Initial contraction to CSE was dependent on the presence of endothelium, whereas subsequent relaxation was endothelium independent. Initial contraction was significantly attenuated by superoxide dismutase (SOD), methylene blue, but not by catalase. Prior inhibition of the basal release of endothelium-derived relaxing factor by NG-monomethyl-L-arginine also inhibited the initial contraction, and this inhibition was reversed by coincubation with L-arginine but not D-arginine. Subsequent relaxation was significantly potentiated by SOD but was markedly attenuated by methylene blue. CSE reduced ferricytochrome c, and this reduction was significantly inhibited by SOD. In conclusion, CSE induced biphasic tension change, initial contraction, and subsequent relaxation during stable contraction to PGF2 alpha in isolated pig coronary arteries. The initial contraction may be, at least in part, mediated through the degradation of basally released endothelium-derived relaxing factor (nitric oxide) by superoxide anions derived from CSE. PMID:8160834

  9. Brain-Specific Superoxide Dismutase 2 Deficiency Causes Perinatal Death with Spongiform Encephalopathy in Mice.

    PubMed

    Izuo, Naotaka; Nojiri, Hidetoshi; Uchiyama, Satoshi; Noda, Yoshihiro; Kawakami, Satoru; Kojima, Shuji; Sasaki, Toru; Shirasawa, Takuji; Shimizu, Takahiko

    2015-01-01

    Oxidative stress is believed to greatly contribute to the pathogenesis of various diseases, including neurodegeneration. Impairment of mitochondrial energy production and increased mitochondrial oxidative damage are considered early pathological events that lead to neurodegeneration. Manganese superoxide dismutase (Mn-SOD, SOD2) is a mitochondrial antioxidant enzyme that converts toxic superoxide to hydrogen peroxide. To investigate the pathological role of mitochondrial oxidative stress in the central nervous system, we generated brain-specific SOD2-deficient mice (B-Sod2(-/-)) using nestin-Cre-loxp system. B-Sod2(-/-) showed perinatal death, along with severe growth retardation. Interestingly, these mice exhibited spongiform neurodegeneration in motor cortex, hippocampus, and brainstem, accompanied by gliosis. In addition, the mutant mice had markedly decreased mitochondrial complex II activity, but not complex I or IV, in the brain based on enzyme histochemistry. Furthermore, brain lipid peroxidation was significantly increased in the B-Sod2(-/-), without any compensatory alterations of the activities of other antioxidative enzymes, such as catalase or glutathione peroxidase. These results suggest that SOD2 protects the neural system from oxidative stress in the perinatal stage and is essential for infant survival and central neural function in mice. PMID:26301039

  10. Mitochondrial superoxide dismutase deficiency accelerates chronological aging in the fission yeast Schizosaccharomyces pombe.

    PubMed

    Ogata, Toshiya; Senoo, Takanori; Kawano, Shinji; Ikeda, Shogo

    2016-01-01

    A mitochondrial superoxide dismutase (SOD2) is the first line of antioxidant defense against mitochondrial superoxide. Even though the involvement of SOD2 in lifespan has been studied extensively in several organisms, characterization of the aging process has not been performed for the sod2 mutant (sod2Δ) of a prominent model Schizosaccharomyces pombe. In this study, we measured the chronological lifespan of sod2Δ cells by their ability to survive in long-term culture. SOD2 deficiency drastically decreased cell viability in the stationary phase. The mutation frequency of nuclear DNA in sod2Δ was elevated in the stationary phase, and cellular proteins and nuclear DNA were extensively degraded, concurrent with cell death. The sod2 gene in wild-type cells could be induced by an increase in endogenous oxidative stresses, after which, SOD2 activity was substantially elevated during the stationary phase. Culture in a lower glucose concentration (calorie restriction) prominently extended the sod2Δ lifespan. Therefore, S. pombe SOD2 plays a critical role in longevity through its upregulation in the non-dividing phase.

  11. Evolutive and structural characterization of Nostoc commune iron-superoxide dismutase that is fit for modification.

    PubMed

    Ma, Y; Lu, M; Li, J-Y; Qin, Y; Gong, X-G

    2012-01-01

    Superoxide dismutase (SOD) has extensive clinical applications for protecting organisms from toxic oxidation. In this study, the integrated iron-superoxide dismutase gene (fe-sod) coding sequence of Nostoc commune stain CHEN was cloned from genomic DNA and compared to sods from other reported algae. These analyses of immunology and phylogenetics indicated that this Fe-SOD is considerably homologous with SODs from lower prokaryotes (Fe-SOD or Mn-SOD) but not those from higher animals (Cu/Zn-SOD). In addition, the N. commune Fe-SOD shows 67 to 93% protein sequence identity to 10 other algal Fe-SODs (or Mn-SODs) and 69 to 93% gene sequence identity. Rare nonsynonymous substitutions imply that algal SODs are being subjected to strong natural selection. Interestingly, the N. commune Fe-SOD enzyme molecule has a compact active center that is highly conserved (38.1% of residues are absolutely conserved), and 2 loose ends localized outside the molecule and inclined to mutate (only 11.5% of residues are absolutely conserved). Based on associative analyses of evolution, structure, and function, this special phenomenon is attributed to function-dependent evolution through negative natural selection. Under strong natural selection, although the mutation is random on the gene level, the exterior region is inclined to mutate on the protein level owing to more nonsynonymous substitutions in the exterior region, which demonstrates the theoretical feasibility of modifying Fe-SOD on its ends to overcome its disadvantages in clinical applications. PMID:23096686

  12. The role of superoxide anion and hydrogen peroxide in phagocytosis-associated oxidative metabolic reactions.

    PubMed Central

    Baehner, R L; Murrmann, S K; Davis, J; Johnston, R B

    1975-01-01

    The contribution of hydrogen peroxide (H2O2) and one of its unstable intermediates, superoxide anion (O2), to the oxidative reactions that occur in phagocytizing leukocytes was explored by depleting these cells of O2. This was accomplished by allowing them to phagocytize latex particles coated with superoxide dismutase (SOD), which catalyzes the generation of H2O2 from O2. Although the rate and extent of phagocytosis of latex coated with bovine serum albumin was similar to latex coated with SOD, the rate of oxygen consumption, [14C]formate oxidation, [1-14C]glucose oxidation, and iodination of zymosan particles was significantly enhanced by SOD. In contrast, the rate and extent of reduction of nitroblue tetrazolium (NBT) was diminished by 60%. These studies indicate that the majority of NBT reduction by leukocytes is due to O2, whereas stimulation of the hexose monophosphate shunt and iodination of ingested particles requires H2O2 generated from the increased reduction of oxygen by phagocytizing leukocytes. PMID:169293

  13. Rapid reaction of nanomolar Mn(II) with superoxide radical in seawater and simulated freshwater

    USGS Publications Warehouse

    Hansard, S.P.; Easter, H.D.; Voelker, B.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.

  14. Copper (II) - HisAibGly complex and its superoxide dismutase activity.

    PubMed

    Singh, Raj K; Prasad, Sudhanand; Singh, Udai P

    2010-02-01

    The superoxide anion radical is a highly reactive toxic species produced during metabolic processes. Several copper (II) complexes with peptides are known to show superoxide dismutase (SOD) activity but those having a peptide with a non-natural amino acid are limited. The synthesis of HisAibGly peptide and its complexation with copper (II) ions has been reported. The interaction of the synthetic peptide with Cu(II) was studied by electron spray ionization-mass (ESI-MS), circular dichroism (CD), absorption (UV-Vis) and electron paramagnetic resonance (EPR) spectroscopic methods. The solution studies and species distribution were performed by both spectrophotometric and potentiometric methods. The studies were performed at 25 + 0.1 degrees C with constant ionic strength (micro = 0.1 M NaNO(3)) in aqueous solution using Bjerrum-Calvin's pH-titration technique as adopted by Irving and Rossotti for binary systems. The species distribution stidies indicated that the complexation occurred from 3-11 pH and a three nitrogen coordinated species predominates at 8-9 whereas a four nitrogen coordinated species was formed between pH 9-11. The copper-peptide complex was tested for SOD activity using xanthine-xanthine oxidase - nitroblue tetrazolium (NBT) methods. PMID:20214649

  15. 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

    2008-03-01

    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). PMID:18254618

  16. Enhancement of oxidative stress tolerance in transgenic tobacco plants overproducing Fe-superoxide dismutase in chloroplasts.

    PubMed Central

    Van Camp, W; Capiau, K; Van Montagu, M; Inzé, D; Slooten, L

    1996-01-01

    A chimeric gene consisting of the coding sequence for chloroplastic Fe superoxide dismutase (FeSOD) from Arabidopsis thaliana, coupled to the chloroplast targeting sequence from the pea ribulose-1,5-bisphosphate carboxylase/oxygenase small subunit, was expressed in Nicotiana tabacum cv Petit Havana SR1. Expression of the transgenic FeSOD protected both the plasmalemma and photosystem II against superoxide generated during illumination of leaf discs impregnated with methyl viologen. By contrast, overproduction of a mitochondrial MnSOD from Nicotiana plumbaginifolia in the chloroplasts of cv SR1 protected only the plasmalemma, but not photosystem II, against methyl viologen (L. Slooten, K. Capiau, W. Van Camp, M. Van Montagu, C. Sybesma, D. Inzé [1995] Plant Physiol 107: 737-750). The difference in effectiveness correlates with different membrane affinities of the transgenic FeSOD and MnSOD. Overproduction of FeSOD does not confer tolerance to H2O2, singlet oxygen, chilling-induced photoinhibition in leaf disc assays, or to salt stress at the whole plant level. In nontransgenic plants, salt stress led to a 2- to 3-fold increase in activity, on a protein basis, of FeSOD, cytosolic and chloroplastic Cu/ZnSOD, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase. In FeSOD-overproducing plants under salt stress, the induction of cytosolic and chloroplastic Cu/ZnSOD was suppressed, whereas induction of a water-soluble chloroplastic ascorbate peroxidase isozyme was promoted. PMID:8972606

  17. Ras Oncogene-Mediated Progressive Silencing of Extracellular Superoxide Dismutase in Tumorigenesis

    PubMed Central

    Cammarota, Francesca; de Vita, Gabriella; Salvatore, Marco; Laukkanen, Mikko O.

    2015-01-01

    Extracellular superoxide dismutase (SOD3) is a secreted enzyme that uses superoxide anion as a substrate in a dismutase reaction that results in the formation of hydrogen peroxide. Both of these reactive oxygen species affect growth signaling in cells. Although SOD3 has growth-supporting characteristics, the expression of SOD3 is downregulated in epithelial cancer cells. In the current work, we studied the mechanisms regulating SOD3 expression in vitro using thyroid cell models representing different stages of thyroid cancer. We demonstrate that a low level of RAS activation increases SOD3 mRNA synthesis that then gradually decreases with increasing levels of RAS activation and the decreasing degree of differentiation of the cancer cells. Our data indicate that SOD3 regulation can be divided into two classes. The first class involves RAS–driven reversible regulation of SOD3 expression that can be mediated by the following mechanisms: RAS GTPase regulatory genes that are responsible for SOD3 self-regulation; RAS-stimulated p38 MAPK activation; and RAS-activated increased expression of the mir21 microRNA, which inversely correlates with sod3 mRNA expression. The second class involves permanent silencing of SOD3 mediated by epigenetic DNA methylation in cells that represent more advanced cancers. Therefore, the work suggests that SOD3 belongs to the group of ras oncogene-silenced genes. PMID:26550576

  18. Brain-Specific Superoxide Dismutase 2 Deficiency Causes Perinatal Death with Spongiform Encephalopathy in Mice

    PubMed Central

    Izuo, Naotaka; Nojiri, Hidetoshi; Uchiyama, Satoshi; Noda, Yoshihiro; Kawakami, Satoru; Kojima, Shuji; Sasaki, Toru; Shirasawa, Takuji; Shimizu, Takahiko

    2015-01-01

    Oxidative stress is believed to greatly contribute to the pathogenesis of various diseases, including neurodegeneration. Impairment of mitochondrial energy production and increased mitochondrial oxidative damage are considered early pathological events that lead to neurodegeneration. Manganese superoxide dismutase (Mn-SOD, SOD2) is a mitochondrial antioxidant enzyme that converts toxic superoxide to hydrogen peroxide. To investigate the pathological role of mitochondrial oxidative stress in the central nervous system, we generated brain-specific SOD2-deficient mice (B-Sod2−/−) using nestin-Cre-loxp system. B-Sod2−/− showed perinatal death, along with severe growth retardation. Interestingly, these mice exhibited spongiform neurodegeneration in motor cortex, hippocampus, and brainstem, accompanied by gliosis. In addition, the mutant mice had markedly decreased mitochondrial complex II activity, but not complex I or IV, in the brain based on enzyme histochemistry. Furthermore, brain lipid peroxidation was significantly increased in the B-Sod2−/−, without any compensatory alterations of the activities of other antioxidative enzymes, such as catalase or glutathione peroxidase. These results suggest that SOD2 protects the neural system from oxidative stress in the perinatal stage and is essential for infant survival and central neural function in mice. PMID:26301039

  19. Production of Superoxide Anions by Keratinocytes Initiates P. acnes-Induced Inflammation of the Skin

    PubMed Central

    Grange, Philippe A.; Chéreau, Christiane; Raingeaud, Joël; Nicco, Carole; Weill, Bernard

    2009-01-01

    Acne vulgaris is a chronic inflammatory disorder of the sebaceous follicles. Propionibacterium acnes (P. acnes), a gram-positive anareobic bacterium, plays a critical role in the development of these inflammatory lesions. This study aimed at determining whether reactive oxygen species (ROS) are produced by keratinocytes upon P. acnes infection, dissecting the mechanism of this production, and investigating how this phenomenon integrates in the general inflammatory response induced by P. acnes. In our hands, ROS, and especially superoxide anions (O2•−), were rapidly produced by keratinocytes upon stimulation by P. acnes surface proteins. In P. acnes-stimulated keratinocytes, O2•− was produced by NAD(P)H oxidase through activation of the scavenger receptor CD36. O2•− was dismuted by superoxide dismutase to form hydrogen peroxide which was further detoxified into water by the GSH/GPx system. In addition, P. acnes-induced O2•− abrogated P. acnes growth and was involved in keratinocyte lysis through the combination of O2•− with nitric oxide to form peroxynitrites. Finally, retinoic acid derivates, the most efficient anti-acneic drugs, prevent O2•− production, IL-8 release and keratinocyte apoptosis, suggesting the relevance of this pathway in humans. PMID:19629174

  20. In vivo real-time measurement of superoxide anion radical with a novel electrochemical sensor.

    PubMed

    Fujita, Motoki; Tsuruta, Ryosuke; Kasaoka, Shunji; Fujimoto, Kenji; Tanaka, Ryo; Oda, Yasutaka; Nanba, Masahiro; Igarashi, Masatsugu; Yuasa, Makoto; Yoshikawa, Toshikazu; Maekawa, Tsuyoshi

    2009-10-01

    The dynamics of superoxide anion (O(2)(-)) in vivo remain to be clarified because no appropriate method exists to directly and continuously monitor and evaluate O(2)(-) in vivo. Here, we establish an in vivo method using a novel electrochemical O(2)(-) sensor. O(2)(-) generated is measured as a current and evaluated as a quantified partial value of electricity (Q(part)), which is calculated by integration of the difference between the baseline and the actual reacted current. The accuracy and efficacy of this method were confirmed by dose-dependent O(2)(-) generation in xanthine-xanthine oxidase in vitro in phosphate-buffered saline and human blood. It was then applied to endotoxemic rats in vivo. O(2)(-) current began to increase 1 h after lipopolysaccharide, and Q(part) increased significantly for 6 h in endotoxemic rats, in comparison to sham-treated rats. These values were attenuated by superoxide dismutase. The generation and attenuation of O(2)(-) were indirectly confirmed by plasma lipid peroxidation with malondialdehyde, endothelial injury with soluble intercellular adhesion molecule-1, and microcirculatory dysfunction. This is a novel method for measuring O(2)(-) in vivo and could be used to monitor and treat the pathophysiology caused by excessive O(2)(-) generation in animals and humans.

  1. Investigation of the Highly Active Manganese Superoxide Dismutase from Saccharomyces cerevisiae

    SciTech Connect

    Cabelli, D.E.; Barnese, K.; Sheng, Y.; Stich, T.A.; Gralla, E.B.; Britt, R.D.; Valentine, J.S.

    2010-09-15

    Manganese superoxide dismutase (MnSOD) from different species differs in its efficiency in removing high concentrations of superoxide (O{sub 2}{sup -}), due to different levels of product inhibition. Human MnSOD exhibits a substantially higher level of product inhibition than the MnSODs from bacteria. In order to investigate the mechanism of product inhibition and whether it is a feature common to eukaryotic MnSODs, we purified MnSOD from Saccharomyces cerevisiae (ScMnSOD). It was a tetramer with 0.6 equiv of Mn per monomer. The catalytic activity of ScMnSOD was investigated by pulse radiolysis and compared with human and two bacterial (Escherichia coli and Deinococcus radiodurans) MnSODs. To our surprise, ScMnSOD most efficiently facilitates removal of high concentrations of O{sub 2}{sup -} among these MnSODs. The gating value k{sub 2}/k{sub 3} that characterizes the level of product inhibition scales as ScMnSOD > D. radiodurans MnSOD > E. coli MnSOD > human MnSOD. While most MnSODs rest as the oxidized form, ScMnSOD was isolated in the Mn{sup 2+} oxidation state as revealed by its optical and electron paramagnetic resonance spectra. This finding poses the possibility of elucidating the origin of product inhibition by comparing human MnSOD with ScMnSOD.

  2. Cytoplasmic superoxide dismutase and catalase activity and resistance to radiation lethality in murine tumor cells

    SciTech Connect

    Davy, C.A.; Tesfay, Z.; Jones, J.; Rosenberg, R.C.; McCarthy, C.; Rosenberg, S.O.

    1986-05-01

    Reduced species of molecular oxygen are produced by the interaction of ionizing radiation with aqueous solutions containing molecular oxygen. The enzymes catalase and superoxide dismutase (SOD) are thought to function in vivo as scavengers of metabolically produced peroxide and superoxide respectively. SOD has been shown to protect against the lethal effects of ionizing radiation in vitro and in vivo. The authors have investigated the relationship between the cytosolic SOD catalase content and the sensitivity to radiation lethality of a number of murine cell lines (402AX, EL-4, MB-2T3, MB-4, MEL, P-815, SAI, SP-2, and SV-3T3). K/sub i/(CN/sup -/) for murine Cu-Zn-SOD was determined to be 6.8 x 10/sup -6/ M. No cytosolic Mn-SOD activity was found in any of the cell lines studied. No correlation was found between the cytosolic Cu-Zn-SOD or cytosolic catalase activity and the resistance to radiation lethality or the murine cell lines studied.

  3. Featured Article: Effect of copper on nuclear translocation of copper chaperone for superoxide dismutase-1.

    PubMed

    Wang, Lin; Ge, Yan; Kang, Y James

    2016-08-01

    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.

  4. Effects of salinity change on two superoxide dismutases (SODs) in juvenile marbled eel Anguilla marmorata

    PubMed Central

    2016-01-01

    Salinity is one of the most important factors that affect the fish growth and survival. Superoxide dismutases (SODs), as the primary antioxidant enzymes, play a first role in the process of preventing oxidative stress caused by excessive superoxide anion (O\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${}_{2}^{-}$\\end{document}2−) in living organisms. In the present study, we investigated the effects of salinity on the gene expressions as well as enzymatic activities of MnSOD and Cu/ZnSOD in gill, intestine, kidney, liver and muscle tissues of the marbled eel Anguilla marmorata. We found that the liver might possess stronger redox capacity compared with other tissues. Furthermore, the gene expressions and enzymatic activities of SODs in juvenile marbled eels could be effectively enhanced by low salinity but inhibited when the salinity was higher than the body tolerance. Our findings indicated that MnSOD and Cu/ZnSOD played vital roles in the adaptation of marbled eels to salinity variation, which contributed to the elucidation of physiological adaptation and regulatory mechanism of SODs in eels. PMID:27547518

  5. Brain-Specific Superoxide Dismutase 2 Deficiency Causes Perinatal Death with Spongiform Encephalopathy in Mice.

    PubMed

    Izuo, Naotaka; Nojiri, Hidetoshi; Uchiyama, Satoshi; Noda, Yoshihiro; Kawakami, Satoru; Kojima, Shuji; Sasaki, Toru; Shirasawa, Takuji; Shimizu, Takahiko

    2015-01-01

    Oxidative stress is believed to greatly contribute to the pathogenesis of various diseases, including neurodegeneration. Impairment of mitochondrial energy production and increased mitochondrial oxidative damage are considered early pathological events that lead to neurodegeneration. Manganese superoxide dismutase (Mn-SOD, SOD2) is a mitochondrial antioxidant enzyme that converts toxic superoxide to hydrogen peroxide. To investigate the pathological role of mitochondrial oxidative stress in the central nervous system, we generated brain-specific SOD2-deficient mice (B-Sod2(-/-)) using nestin-Cre-loxp system. B-Sod2(-/-) showed perinatal death, along with severe growth retardation. Interestingly, these mice exhibited spongiform neurodegeneration in motor cortex, hippocampus, and brainstem, accompanied by gliosis. In addition, the mutant mice had markedly decreased mitochondrial complex II activity, but not complex I or IV, in the brain based on enzyme histochemistry. Furthermore, brain lipid peroxidation was significantly increased in the B-Sod2(-/-), without any compensatory alterations of the activities of other antioxidative enzymes, such as catalase or glutathione peroxidase. These results suggest that SOD2 protects the neural system from oxidative stress in the perinatal stage and is essential for infant survival and central neural function in mice.

  6. Manganese Phosphate Self-assembled Nanoparticle Surface and Its application for Superoxide Anion Detection

    PubMed Central

    Shen, Xiaohui; Wang, Qi; Liu, Yuhong; Xue, Wenxiao; Ma, Lie; Feng, Shuaihui; Wan, Mimi; Wang, Fenghe; Mao, Chun

    2016-01-01

    Quantitative analysis of superoxide anion (O2·−) has increasing importance considering its potential damages to organism. Herein, a novel Mn-superoxide dismutase (MnSOD) mimics, silica-manganous phosphate (SiO2-Mn3(PO4)2) nanoparticles, were designed and synthesized by surface self-assembly processes that occur on the surface of silica-phytic acid (SiO2-PA) nanoparticles. The composite nanoparticles were characterized by fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electronic microscopy (SEM), electron diffraction pattern, energy dispersive spectroscopy (EDS) and elemental mapping. Then the electrochemical measurements of O2·− based on the incorporation of SiO2-Mn3(PO4)2 onto the surface of electrodes were performed, and some satisfactory results were obtained. This is the first report that manganous phosphate (Mn3(PO4)2) nanoparticles with shape-controlled, but not multilayer sheets, were utilized for O2·− detection. The surface self-assembly technology we proposed will offer the ideal material to construct more types biosensor and catalytic system for its nanosized effect. PMID:27357008

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

    NASA Astrophysics Data System (ADS)

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

    2016-02-01

    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.

  8. Impaired fertilizing ability of superoxide dismutase 1-deficient mouse sperm during in vitro fertilization.

    PubMed

    Tsunoda, Satoshi; Kawano, Natsuko; Miyado, Kenji; Kimura, Naoko; Fujii, Junichi

    2012-11-01

    The oxidative modification of gametes by a reactive oxygen species is a major deleterious factor that decreases the successful rate of in vitro fertilization. Superoxide dismutase 1 (SOD1) plays a pivotal role in antioxidation by scavenging the superoxide anion, and its deficiency causes infertility in female mice, but the significance of the enzyme in male mice remains unclear. In the present study, we characterized Sod1(-/-) (Sod1-KO) male reproductive organs and compiled the first report of the impaired fertilizing ability of Sod1-KO sperm in in vitro fertilization. Insemination of wild-type oocytes with Sod1-KO sperm exhibited lower rates of fertility compared with insemination by wild-type sperm. The low fertilizing ability found for Sod1-KO sperm was partially rescued by reductant 2-mercaptoethanol, which suggested the oxidative modification of sperm components. The numbers of motile and progressive sperm decreased during the in vitro fertilization process, and a decline in ATP content and elevation in lipid peroxidation occurred in the Sod1-KO sperm in an incubation time-dependent manner. Tyrosine phosphorylation, which is a hallmark for sperm capacitation, was also impaired in the Sod1-KO sperm. These results collectively suggest that machinery involved in sperm capacitation and motility are vulnerable to oxidative damage during the in vitro fertilization process, which could increase the rate of inefficient fertilization.

  9. Accelerated aging phenotype in mice with conditional deficiency for mitochondrial superoxide dismutase in the connective tissue.

    PubMed

    Treiber, Nicolai; Maity, Pallab; Singh, Karmveer; Kohn, Matthias; Keist, Alexander F; Ferchiu, Florentina; Sante, Lea; Frese, Sebastian; Bloch, Wilhelm; Kreppel, Florian; Kochanek, Stefan; Sindrilaru, Anca; Iben, Sebastian; Högel, Josef; Ohnmacht, Michael; Claes, Lutz E; Ignatius, Anita; Chung, Jin H; Lee, Min J; Kamenisch, York; Berneburg, Mark; Nikolaus, Thorsten; Braunstein, Kerstin; Sperfeld, Anne-Dorte; Ludolph, Albert C; Briviba, Karlis; Wlaschek, Meinhard; Florin, Lore; Angel, Peter; Scharffetter-Kochanek, Karin

    2011-04-01

    The free radical theory of aging postulates that the production of mitochondrial reactive oxygen species is the major determinant of aging and lifespan. Its role in aging of the connective tissue has not yet been established, even though the incidence of aging-related disorders in connective tissue-rich organs is high, causing major disability in the elderly. We have now addressed this question experimentally by creating mice with conditional deficiency of the mitochondrial manganese superoxide dismutase in fibroblasts and other mesenchyme-derived cells of connective tissues in all organs. Here, we have shown for the first time that the connective tissue-specific lack of superoxide anion detoxification in the mitochondria results in reduced lifespan and premature onset of aging-related phenotypes such as weight loss, skin atrophy, kyphosis (curvature of the spine), osteoporosis and muscle degeneration in mutant mice. Increase in p16(INK4a) , a robust in vivo marker for fibroblast aging, may contribute to the observed phenotype. This novel model is particularly suited to decipher the underlying mechanisms and to develop hopefully novel connective tissue-specific anti-aging strategies.

  10. Potential mechanisms for the inhibition of tumor cell growth by manganese superoxide dismutase.

    PubMed

    Kim, K H; Rodriguez, A M; Carrico, P M; Melendez, J A

    2001-06-01

    Studies from many laboratories have shown that overexpression of manganese superoxide dismutase (MnSOD) inhibits the growth of numerous tumor cell types. The inhibition of tumor cell growth can be attributed to the increase in the steady-state levels of H2O2 as a result of the increased dismuting activity of MnSOD. Here we demonstrate that overexpression of MnSOD enhances the activity of the superoxide (O2*-)-sensitive enzyme aconitase, decreases the intracellular GSH/GSSG ratio, and dose-dependently inhibits pyruvate carboxylase activity. Thus, alterations in the steady-state concentrations of mitochondrial O2*- and H2O2 as a result of MnSOD overexpression can alter the metabolic capacity of the cell leading to inhibition of cell growth. Furthermore, we propose that MnSOD overexpression can modulate the activity of nitric oxide (*NO) by preventing its reaction with O2*-. This hypothesis suggests that the redox environment of the mitochondria can be altered to favor the activity of *NO rather than peroxynitrite (ONOO-) and may explain the enhanced toxicity of *NO-generating compounds toward MnSOD-overexpressing cell lines. These findings indicate that therapeutic strategies targeted at overexpressing MnSOD in tumor tissue may be more effective when used in combination with agents that deplete the oxidant-buffering and enhance the *NO-generating capacity of the tumor and host, respectively. PMID:11491650

  11. Extracellular haem peroxidases mediate Mn(II) oxidation in a marine Roseobacter bacterium via superoxide production.

    PubMed

    Andeer, Peter F; Learman, Deric R; McIlvin, Matt; Dunn, James A; Hansel, Colleen M

    2015-10-01

    Manganese (Mn) oxides are among the strongest sorbents and oxidants in environmental systems. A number of biotic and abiotic pathways induce the oxidation of Mn(II) to Mn oxides. Here, we use a combination of proteomic analyses and activity assays, to identify the enzyme(s) responsible for extracellular superoxide-mediated Mn oxide formation by a bacterium within the ubiquitous Roseobacter clade. We show that animal haem peroxidases (AHPs) located on the outer membrane and within the secretome are responsible for Mn(II) oxidation. These novel peroxidases have previously been implicated in direct Mn(II) oxidation by phylogenetically diverse bacteria. Yet, we show that in this Roseobacter species, AHPs mediate Mn(II) oxidation not through a direct reaction but by producing superoxide and likely also by degrading hydrogen peroxide. These findings point to a eukaryotic-like oscillatory oxidative-peroxidative enzymatic cycle by these AHPs that leads to Mn oxide formation by this organism. AHP expression appears unaffected by Mn(II), yet the large energetic investment required to produce and secrete these enzymes points to an as yet unknown physiological function. These findings are further evidence that bacterial peroxidases and secreted enzymes, in general, are unappreciated controls on the cycling of metals and reactive oxygen species (ROS), and by extension carbon, in natural systems.

  12. Pathways of superoxide (O2(-)) decay in the Eastern Tropical North Atlantic.

    PubMed

    Wuttig, Kathrin; Heller, Maija I; Croot, Peter L

    2013-09-17

    Superoxide (O2(-): IUPAC name dioxide (•1-)) is an important transient reactive oxygen species (ROS) in the ocean formed as an intermediate in the redox transformation of oxygen (O2) into hydrogen peroxide (H2O2) and vice versa. This highly reactive and very short-lived radical anion can be produced both via photochemical and biological processes in the ocean. In this paper we examine the decomposition rate of O2(-) throughout the water column, using new data collected in the Eastern Tropical North Atlantic (ETNA) Ocean. For this approach we applied a semi factorial experimental design to identify and quantify the pathways of the major identified sinks in the ocean. In this work we occupied six stations, two on the West African continental shelf and four open ocean stations, including the CVOO time series site adjacent to Cape Verde. Our results indicate that, in the surface ocean impacted by Saharan aerosols and coastal sediment resuspension, the main decay pathways for superoxide are via reactions with Mn(II) and organic matter.

  13. Pathways of superoxide (O2(-)) decay in the Eastern Tropical North Atlantic.

    PubMed

    Wuttig, Kathrin; Heller, Maija I; Croot, Peter L

    2013-09-17

    Superoxide (O2(-): IUPAC name dioxide (•1-)) is an important transient reactive oxygen species (ROS) in the ocean formed as an intermediate in the redox transformation of oxygen (O2) into hydrogen peroxide (H2O2) and vice versa. This highly reactive and very short-lived radical anion can be produced both via photochemical and biological processes in the ocean. In this paper we examine the decomposition rate of O2(-) throughout the water column, using new data collected in the Eastern Tropical North Atlantic (ETNA) Ocean. For this approach we applied a semi factorial experimental design to identify and quantify the pathways of the major identified sinks in the ocean. In this work we occupied six stations, two on the West African continental shelf and four open ocean stations, including the CVOO time series site adjacent to Cape Verde. Our results indicate that, in the surface ocean impacted by Saharan aerosols and coastal sediment resuspension, the main decay pathways for superoxide are via reactions with Mn(II) and organic matter. PMID:23915117

  14. Unique Characteristics of Recombinant Hybrid Manganese Superoxide Dismutase from Staphylococcus equorum and S. saprophyticus.

    PubMed

    Retnoningrum, Debbie S; Rahayu, Anis Puji; Mulyanti, Dina; Dita, Astrid; Valerius, Oliver; Ismaya, Wangsa T

    2016-04-01

    A recombinant hybrid of manganese dependent-superoxide dismutase of Staphylococcus equorum and S. saprophyticus has successfully been overexpressed in Escherichia coli BL21(DE3), purified, and characterized. The recombinant enzyme suffered from degradation and aggregation upon storage at -20 °C, but not at room temperature nor in cold. Chromatographic analysis in a size exclusion column suggested the occurrence of dimeric form, which has been reported to contribute in maintaining the stability of the enzyme. Effect of monovalent (Na(+), K(+)), divalent (Ca(2+), Mg(2+)), multivalent (Mn(2+/4+), Zn(2+/4+)) cations and anions (Cl(-), SO4 (2-)) to the enzyme stability or dimeric state depended on type of cation or anion, its concentration, and pH. However, tremendous effect was observed with 50 mM ZnSO4, in which thermostability of both the dimer and monomer was increased. Similar situation was not observed with MnSO4, and its presence was detrimental at 200 mM. Finally, chelating agent appeared to destabilize the dimer around neutral pH and dissociate it at basic pH. The monomer remained stable upon addition of ethylene diamine tetraacetic acid. Here we reported unique characteristics and stability of manganese dependent-superoxide dismutase from S. equorum/saprophyticus. PMID:26960678

  15. 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. PMID:26159570

  16. 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. PMID:23245343

  17. Effect of 2, 5-Substituents on the Stability of Cyclic Nitrone Superoxide Spin Adducts: A Density Functional Theory Approach

    PubMed Central

    Du, Li-Bo; Wang, Lan-Fen; Liu, Yang-Ping; Jia, Hong-Ying; Liu, Yang; Liu, Ke Jian; Tian, Qiu

    2011-01-01

    To design efficient spin traps for superoxide radicals, interest in the elucidation of substituent effects on the stability of superoxide spin adducts has become a necessary priority. In the present study, five cyclic nitrone superoxide spin adducts, i.e. DMPO-OOH, M3PO-OOH, EMPO-OOH, DEPMPO-OOH, and DEPDMPO-OOH, were chosen as model compounds to investigate the effect of 2,5-subsitituents on their stability, through structural analysis and decay thermodynamics using density functional theory (DFT) calculations. Analysis of the optimized geometries reveals that none of the previously proposed stabilizing factors, including intramolecular H-bonds, intramolecular nonbonding interactions, bulky steric protection, nor the C(2)–N(1) bond distance can be used to clearly explain the effect of 2,5-substituents on the stability of the spin adducts. Additionally the effect of the 2,5-substituents on the stability of the superoxide spin adducts cannot be simply clarified by Milliken charges on both atoms (nitroxyl nitrogen and nitroxyl oxygen). Subsequent study found that spin densities on the nitroxyl nitrogen and oxygen are well correlated with the half-life times of the spin adducts, and consequently are the proper parameters to characterize the effect of 2,5-substituents on their stability. Examination of the decomposition thermodynamics further supports the effect of the substituents on the persistence of cyclic nitrone superoxide spin adducts. PMID:20370568

  18. Superoxide generated from the glutathione-mediated reduction of selenite damages the iron-sulfur cluster of chloroplastic ferredoxin.

    PubMed

    Fisher, Brian; Yarmolinsky, Dmitry; Abdel-Ghany, Salah; Pilon, Marinus; Pilon-Smits, Elizabeth A; Sagi, Moshe; Van Hoewyk, Doug

    2016-09-01

    Selenium assimilation in plants is facilitated by several enzymes that participate in the transport and assimilation of sulfate. Manipulation of genes that function in sulfur metabolism dramatically affects selenium toxicity and accumulation. However, it has been proposed that selenite is not reduced by sulfite reductase. Instead, selenite can be non-enzymatically reduced by glutathione, generating selenodiglutathione and superoxide. The damaging effects of superoxide on iron-sulfur clusters in cytosolic and mitochondrial proteins are well known. However, it is unknown if superoxide damages chloroplastic iron-sulfur proteins. The goals of this study were twofold: to determine whether decreased activity of sulfite reductase impacts selenium tolerance in Arabidopsis, and to determine if superoxide generated from the glutathione-mediated reduction of selenite damages the iron-sulfur cluster of ferredoxin. Our data demonstrate that knockdown of sulfite reductase in Arabidopsis does not affect selenite tolerance or selenium accumulation. Additionally, we provide in vitro evidence that the non-enzymatic reduction of selenite damages the iron-sulfur cluster of ferredoxin, a plastidial protein that is an essential component of the photosynthetic light reactions. Damage to ferredoxin's iron-sulfur cluster was associated with formation of apo-ferredoxin and impaired activity. We conclude that if superoxide damages iron-sulfur clusters of ferredoxin in planta, then it might contribute to photosynthetic impairment often associated with abiotic stress, including toxic levels of selenium. PMID:27182957

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

    SciTech Connect

    Wang, Qiang; Zheng, Dong; McKinnon, Meaghan E.; Yang, Xiao -Qing; Qu, Deyang

    2014-10-28

    Superoxide reacts with carbonate solvents in Li–air batteries. Tris(pentafluorophenyl)borane is found to catalyze a more rapid superoxide (O2-) disproportionation reaction than the reaction between superoxide and propylene carbonate (PC). With this catalysis, the negative impact of the reaction between the electrolyte and O2-produced by the O2 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 order 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.

  20. Effect of academic psychological stress in post-graduate students: the modulatory role of cortisol on superoxide release by neutrophils.

    PubMed

    Ignacchiti, M D C; Sesti-Costa, R; Marchi, L F; Chedraoui-Silva, S; Mantovani, B

    2011-05-01

    Experimental and clinical evidence shows that neutrophils play an important role in the mechanism of tissue injury in immune complex diseases through the generation of reactive oxygen species. In this study, we examined the influence of academic psychological stress in post-graduate students on the capacity of their blood neutrophils to release superoxide when stimulated by immune complexes bound to nonphagocytosable surfaces and investigated the modulatory effect of cortisol on this immune function. The tests were performed on the day before the final examination. The state-trait anxiety inventory questionnaire was used to examine whether this stressful event caused emotional distress. In our study, the psychological stress not only increased plasma cortisol concentration, but it also provoked a reduction in superoxide release by neutrophils. This decrease in superoxide release was accompanied by diminished mRNA expression for subunit p47(phox) of the phagocyte superoxide-generating nicotinamide adenine dinucleotide phosphate-oxidase. These inhibitory effects were also observed by in vitro exposure of neutrophils from control volunteers to 10(- 7) M hydrocortisone, and could be prevented by the glucocorticoid receptor antagonist RU-486. These results show that in a situation of psychological stress, the increased levels of cortisol could inhibit superoxide release by neutrophils stimulated by IgG immune complexes bound to nonphagocytosable surfaces, which could attenuate the inflammatory state.

  1. Cu, Zn Superoxide Dismutase and NADP(H) Homeostasis Are Required for Tolerance of Endoplasmic Reticulum Stress in Saccharomyces cerevisiae

    PubMed Central

    Tan, Shi-Xiong; Teo, Mariati; Lam, Yuen T.; Perrone, Gabriel G.

    2009-01-01

    Genome-wide screening for sensitivity to chronic endoplasmic reticulum (ER) stress induced by dithiothreitol and tunicamycin (TM) identified mutants deleted for Cu, Zn superoxide dismutase (SOD) function (SOD1, CCS1) or affected in NADPH generation via the pentose phosphate pathway (TKL1, RPE1). TM-induced ER stress led to an increase in cellular superoxide accumulation and an increase in SOD1 expression and Sod1p activity. Prior adaptation of the hac1 mutant deficient in the unfolded protein response (UPR) to the superoxide-generating agent paraquat reduced cell death under ER stress. Overexpression of the ER oxidoreductase Ero1p known to generate hydrogen peroxide in vitro, did not lead to increased superoxide levels in cells subjected to ER stress. The mutants lacking SOD1, TKL1, or RPE1 exhibited decreased UPR induction under ER stress. Sensitivity of the sod1 mutant to ER stress and decreased UPR induction was partially rescued by overexpression of TKL1 encoding transketolase. These data indicate an important role for SOD and cellular NADP(H) in cell survival during ER stress, and it is proposed that accumulation of superoxide affects NADP(H) homeostasis, leading to reduced UPR induction during ER stress. PMID:19129474

  2. Superoxide triggers an acid burst in Saccharomyces cerevisiae to condition the environment of glucose-starved cells.

    PubMed

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

    2013-02-15

    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.

  3. Superoxide generated from the glutathione-mediated reduction of selenite damages the iron-sulfur cluster of chloroplastic ferredoxin.

    PubMed

    Fisher, Brian; Yarmolinsky, Dmitry; Abdel-Ghany, Salah; Pilon, Marinus; Pilon-Smits, Elizabeth A; Sagi, Moshe; Van Hoewyk, Doug

    2016-09-01

    Selenium assimilation in plants is facilitated by several enzymes that participate in the transport and assimilation of sulfate. Manipulation of genes that function in sulfur metabolism dramatically affects selenium toxicity and accumulation. However, it has been proposed that selenite is not reduced by sulfite reductase. Instead, selenite can be non-enzymatically reduced by glutathione, generating selenodiglutathione and superoxide. The damaging effects of superoxide on iron-sulfur clusters in cytosolic and mitochondrial proteins are well known. However, it is unknown if superoxide damages chloroplastic iron-sulfur proteins. The goals of this study were twofold: to determine whether decreased activity of sulfite reductase impacts selenium tolerance in Arabidopsis, and to determine if superoxide generated from the glutathione-mediated reduction of selenite damages the iron-sulfur cluster of ferredoxin. Our data demonstrate that knockdown of sulfite reductase in Arabidopsis does not affect selenite tolerance or selenium accumulation. Additionally, we provide in vitro evidence that the non-enzymatic reduction of selenite damages the iron-sulfur cluster of ferredoxin, a plastidial protein that is an essential component of the photosynthetic light reactions. Damage to ferredoxin's iron-sulfur cluster was associated with formation of apo-ferredoxin and impaired activity. We conclude that if superoxide damages iron-sulfur clusters of ferredoxin in planta, then it might contribute to photosynthetic impairment often associated with abiotic stress, including toxic levels of selenium.

  4. The interactions of superoxide ion(O2-.) with metallo-porphyrins [(C1(8)TPP)M, M = Fe,Mn,Co Zn]; models for biological systems and superoxide dismutases.

    PubMed

    Sawyer, D T; Tsang, P K

    1991-01-01

    In dimethylformamide superoxide ion forms a 1:1 adduct with tetrakis (2,6-dichlorophenyl) porphinato-iron, (C1(8)TPP)FeOO-, as well as with its manganese analogue, (C1(8)TPP)MnOO-. On the basis of their electrochemical, spectroscopic, and magnetic properties these adducts have a metal-oxygen covalent bond (PorM-OO-), oxygen-centered redox chemistry, and reactivities that are similar to the hydroperoxide ion (HOO-). Addition of -OH to a solution of PorFe and O2 results in the formation of PorFe(OH)(OO-), which can be electrochemically oxidized to PorFeOH plus O2 (-0.2 V vs SCE). Addition of protons to the PorM-OO- adducts promotes their rapid decomposition to PorM, HOOH, and O2. This chemistry provides insight to the reactions of biological superoxide and superoxide dismutases. PMID:1649106

  5. Comparison of the crystal structures of genetically engineered human manganese superoxide dismutase and manganese superoxide dismutase from Thermus thermophilus: differences in dimer-dimer interaction.

    PubMed Central

    Wagner, U. G.; Pattridge, K. A.; Ludwig, M. L.; Stallings, W. C.; Werber, M. M.; Oefner, C.; Frolow, F.; Sussman, J. L.

    1993-01-01

    The three-dimensional X-ray structure of a recombinant human mitochondrial manganese superoxide dismutase (MnSOD) (chain length 198 residues) was determined by the method of molecular replacement using the related structure of MnSOD from Thermus thermophilus as a search model. This tetrameric human MnSOD crystallizes in space group P2(1)2(1)2 with a dimer in the asymmetric unit (Wagner, U.G., Werber, M.M., Beck, Y., Hartman, J.R., Frolow, F., & Sussman, J.L., 1989, J. Mol. Biol. 206, 787-788). Refinement of the protein structure (3,148 atoms with Mn and no solvents), with restraints maintaining noncrystallographic symmetry, converged at an R-factor of 0.207 using all data from 8.0 to 3.2 A resolution and group thermal parameters. The monomer-monomer interactions typical of bacterial Fe- and Mn-containing SODs are retained in the human enzyme, but the dimer-dimer interactions that form the tetramer are very different from those found in the structure of MnSOD from T. thermophilus. In human MnSOD one of the dimers is rotated by 84 degrees relative to its equivalent in the thermophile enzyme. As a result the monomers are arranged in an approximately tetrahedral array, the dimer-dimer packing is more intimate than observed in the bacterial MnSOD from T. thermophilus, and the dimers interdigitate. The metal-ligand interactions, determined by refinement and verified by computation of omit maps, are identical to those observed in T. thermophilus MnSOD. PMID:8495200

  6. Autoxidation of soluble trypsin-cleaved microsomal ferrocytochrome b5 and formation of superoxide radicals.

    PubMed

    Berman, M C; Adnams, C M; Ivanetich, K M; Kench, J E

    1976-07-01

    The rate and mechanism of autoxidation of soluble ferrocytochrome b5, prepared from liver microsomal suspensions, appear to reflect an intrinsic property of membrane-bound cytochrome b5. The first-order rate constant for autoxidation of trypsin-cleaved ferrocytochrome b5, prepared by reduction with dithionite, was 2.00 X 10(-3) +/- 0.19 X 10(-3) S-1 (mean +/- S.E.M., n =8) when measured at 30 degrees C in 10 mM-phosphate buffer, pH 7.4. At 37 degrees C in aerated 10 mM-phosphate buffer (pH 7.4)/0.15 M-KCl, the rate constant was 5.6 X 10(-3) S-1. The autoxidation reaction was faster at lower pH values and at high ionic strengths. Unlike ferromyoglobin, the autoxidation reaction of which is maximal at low O2 concentrations, autoxidation of ferrocytochrome b5 showed a simple O2-dependence with an apparent Km for O2 of 2.28 X 10(-4) M (approx. 20kPa or 150mmHg)9 During autoxidation, 0.25 mol of O2 was consumed per mol of cytochrome oxidized. Cyanide, nucleophilic anions, EDTA and catalase each had little or no effect on autoxidation rates. Adrenaline significantly enhanced autoxidation rates, causing a tenfold increase at 0.6 mM. Ferrocytochrome b5 reduced an excess of cytochrome c in a biphasic manner. An initial rapid phase, independent of O2 concentration, was unaffected by superoxide dismutase. A subsequent slower phase, which continued for up to 60 min, was retarded at low O2 concentrations and inhibited by 65% by superoxide dismutase at a concentration of 3 mug/ml. It is concluded that autoxidation is responsible for a significant proportion of electron flow between cytochrome b5 and O2 in liver endoplasmic membranes, this reaction being capable of generating superoxide anions. A biological role for the reaction is discussed. PMID:183743

  7. Blockade of monocyte-endothelial trafficking by transduced Tat-superoxide dismutase protein.

    PubMed

    Park, Sin-Hye; Shin, Min Jae; Kim, Dae Won; Park, Jinseu; Choi, Soo Young; Kang, Young-Hee

    2016-02-01

    It has previously been suggested that reactive oxygen species (ROS) are involved in the pathogenesis of chronic inflammatory diseases, which entails the initial activation of pro-inflammatory cytokines to facilitate leukocyte transmigration. The present study investigated whether intracellular superoxide dismutase (SOD) suppressed monocyte endothelial trafficking and transmigration. Human umbilical vein endothelial cells (HUVECs) and THP-1 monocytes were activated by the cytokine tumor necrosis factor-α (TNF-α) in the absence and presence of cell-permeable transactivator of transcription (Tat)-SOD protein. External stimulation with SOD was conducted using endothelial cells and monocytes. Purified cell-permeable Tat-SOD, but not non-targeted SOD, at 1-3 µM was transduced into endothelial cells in a time‑ and dose-dependent manner. Non-toxic Tat-SOD at ≤0.5 µM, but not 1 µM SOD, blocked the monocyte-endothelium interactions by inhibiting the TNF-α-induced stimulation of vascular cell adhesion molecule-1 (VCAM-1) in HUVECs and integrin β1 in THP-1 cells. Endothelial VCAM-1 induction by TNF-α was responsible for superoxide anion production being quenched by N-acetyl-cysteine and Tat-SOD. SOD treatment markedly inhibited superoxide anion production induced by TNF-α, but no inhibition of endothelial transmigration was noted. Tat-SOD prevented transendothelial monocyte migration by firmly localizing occludin-1, platelet/endothelial cell adhesion molecule‑1 (PECAM-1) and vascular endothelial‑cadherin present in paracellular junctions and inhibiting endothelial induction and activation of matrix-degrading membrane type-1 (MT-1) matrix metalloproteinase (MMP), MMP-2 and MMP-9. By contrast, treatment with 1 µM SOD did not have such effects. Furthermore, transduced Tat-SOD hindered nuclear transactivation of nuclear factor-κB (NF-κB), modulating the induction of paracellular junction proteins and matrix‑degrading MMP in TNF-α‑stimulated HUVECs

  8. Superoxide dismutase activity in the intestine of the streptozotocin-diabetic rat.

    PubMed

    Loven, D P; Schedl, H P; Oberley, L W; Wilson, H D; Bruch, L; Niehaus, C L

    1982-09-01

    Insulin stimulates the production of superoxide and hydrogen peroxide in various tissues. Hydrogen peroxide has been proposed to be an intracellular second messenger for insulin and a moderator of cellular proliferation and differentiation. We previously found that cell proliferation is increased in small intestinal mucosa of streptozotocin-diabetic rats. The current study was undertaken to determine if superoxide dismutase (SOD), the enzyme that converts superoxide to hydrogen peroxide, is altered in the mucosa of the alimentary tract and renal cortex of the diabetic rat, and if so, whether SOD responds to insulin treatment. Total SOD and cyanide-insensitive [manganese-containing SOD (Mn SOD)] SOD were measured by the nitroblue tetrazolium inhibition assay. We studied ad libitum fed animals, where diabetics are hyperphagic and pair-fed animals, where hyperphagia is not present. Since cyclic nucleotides appear to control cell proliferation in some tissues, we also measured cAMP and cGMP in mucosa of the small intestine. In ad libitum fed animals, total SOD was depressed in the mucosa of duodenum, jejunum, and ileum, but not in the cecum or colon of the streptozotocin-diabetic rats. The level of Mn-SOD was not affected by diabetes or insulin treatment, but the cyanide-sensitive [copper- and zinc containing SOD (Cu-Zn SOD] SOD was depressed in the small intestine and colon of diabetic rats. Insulin treatment restored total and Cu-Zn SOD activity in the small intestine to normal and increased Cu-Zn SOD activity in the colon to normal. Pair-fed animals showed the same changes in the SOD activity of jejunal mucosa that were found in ad libitum fed animals. In renal cortex, diabetes did not alter total SOD, but increased Mn SOD and decreased Cu-Zn SOD. Both responses were reversed by insulin treatment. Cyclic nucleotide concentrations were not affected by diabetes. We conclude that SOD enzymes re altered in diabetes, at least in proliferating tissues. Responses are

  9. Effect of rutin and its copper complex on superoxide formation and lipid peroxidation in rat liver microsomes.

    PubMed

    Afanas'ev, I B; Ostrachovich, E A; Korkina, L G

    1998-03-27

    Two free radical scavengers, bioflavonoid rutin and the copper-rutin complex Cu(Rut)Cl2, inhibited lucigenin-amplified chemiluminescence and lipid peroxidation in rat liver microsomes, Cu(Rut)Cl2 being a 5-9 times more efficient inhibitor than rutin. The enhanced inhibitory activity of Cu(Rut)Cl2 was due to the presence of the additional superoxide-dismutating center (Cu), as follows from the comparison of its effects on microsomal chemiluminescence and cytochrome c reduction by xanthine oxidase. Similar effects of both inhibitors on superoxide production and lipid peroxidation as well as the elevated activity of Cu(Rut)Cl2 indicate an important role of superoxide ion in the initiation of microsomal lipid peroxidation. PMID:9559660

  10. 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.

  11. Adrenergic and serotonin receptors affect retinal superoxide generation in diabetic mice: relationship to capillary degeneration and permeability

    PubMed Central

    Du, Yunpeng; Cramer, Megan; Lee, Chieh Allen; Tang, Jie; Muthusamy, Arivalagan; Antonetti, David A.; Jin, Hui; Palczewski, Krzysztof; Kern, Timothy S.

    2015-01-01

    Reactive oxygen species play an important role in the pathogenesis of diabetic retinopathy. We studied the role of adrenergic and serotonin receptors in the generation of superoxide by retina and 661W retinal cells in high glucose and of the α1-adrenergic receptor (AR) on vascular lesions of the retinopathy in experimentally diabetic C57Bl/6J mice (and controls) after 2 and 8 months. Compared with 5 mM glucose, incubating cells or retinal explants in 30 mM glucose induced superoxide generation. This response was reduced or ablated by pharmacologic inhibition of the α1-AR (a Gq-coupled receptor) or Gs-coupled serotonin (5-HT2, 5-HT4, 5-HT6, and 5-HT7) receptors or by activation of the Gi-coupled α2-AR. In elevated glucose, the α1-AR produced superoxide via phospholipase C, inositol triphosphate-induced Ca2+ release, and NADPH oxidase, and pharmacologic inhibition of these reactions prevented the superoxide increase. Generation of retinal superoxide, expression of proinflammatory proteins, and degeneration of retinal capillaries in diabetes all were significantly inhibited with daily doxazosin or apocynin (inhibitors of α1-AR and NADPH oxidase, respectively), but increased vascular permeability was not significantly affected. Adrenergic receptors, and perhaps other GPCRs, represent novel targets for inhibiting the development of important features of diabetic retinopathy.—Du, Y., Cramer, M., Lee, C. A., Tang, J., Muthusamy, A., Antonetti, D. A., Jin, H., Palczewski, K., Kern, T. S. Adrenergic and serotonin receptors affect retinal superoxide generation in diabetic mice: relationship to capillary degeneration and permeability. PMID:25667222

  12. Copper-zinc alloy nanoparticle based enzyme-free superoxide radical sensing on a screen-printed electrode.

    PubMed

    Derkus, Burak; Emregul, Emel; Emregul, Kaan C

    2015-03-01

    In this paper, amperometric enzyme-free sensors using superoxide dismutase (SOD) enzyme as a catalyst for the dismutation reaction of superoxides into oxygen and hydrogen peroxide, enabling superoxide radical detection have been described. For this purpose, the surfaces of screen-printed platinum electrodes have been modified with gelatin composites of CuO, ZnO and CuZn nanoparticles with the expectation of an increase in catalytic effect toward the dismutation reaction. SOD containing electrodes were also prepared for comparative studies in which glutaraldehyde was used as a cross-linker for the immobilization of SOD to the nanocomposite materials. Electrochemical measurements were carried out using a screen-printed electrochemical system that included potassiumferrocyanide (K4[Fe(CN)6]) and potassiumferricyanide (K3[Fe(CN)6]) as the redox probes. The results revealed that the enzyme-free detection method using CuZn nanoparticles can determine superoxide radicals with high performance compared to other detection methods prepared with different nanoparticles by mimicking the active region of superoxide dismutase enzyme. The anodic (ks(a)) and cathodic (ks(c)) electron transfer rate constants and the anodic (α(a)) and cathodic (α(c)) transfer coefficients were evaluated and found to be ks(a)=6.31 s(-1) and α(a)=0.81, ks(c)=1.48 s(-1) and α(c)=0.19 for the gelatin-CuZn-SOD electrode; ks(a)=6.15 s(-1) and α(a)=0.79, ks(c)=1,63 s(-1) and α(c)=0.21 for the enzyme-free gelatin-CuZn electrode. The enzyme-free electrode showed nearly 80% amperometric performance with respect to the enzyme containing electrode indicating the superior functionality of enzyme-free electrode for the detection of superoxide radicals. PMID:25618659

  13. WISP-3 functions as a ligand and promotes superoxide dismutase activity.

    PubMed

    Davis, Leila; Chen, Yi; Sen, Malini

    2006-03-31

    WISP-3 (Wnt1 inducible secreted protein-3) mutations have been linked to the connective tissue diseases progressive pseudorheumatoid dysplasia and polyarticular juvenile idiopathic arthritis, both of which are accompanied by disorders in cartilage maintenance/homeostasis. The molecular mechanism of WISP-3 mediated effects in the sustenance of cartilage has not been described in detail. Our previous study illustrates the potential role of WISP-3 in regulating the expression of cartilage-specific molecules that sustain chondrocyte growth and cartilage integrity. The present study was conducted to investigate the mode of action of WISP-3 in greater detail. Experimental results depicted here suggest that WISP-3 can function as a ligand and signal via autocrine and/or paracrine modes upon being secreted by chondrocytes. Furthermore, apart from regulating collagen II and aggrecan expression, WISP-3 may also promote superoxide dismutase expression and activity in chondrocytes.

  14. Mitochondria Superoxide Anion Production Contributes to Geranylgeraniol-Induced Death in Leishmania amazonensis

    PubMed Central

    Lopes, Milene Valéria; Desoti, Vânia Cristina; Caleare, Angelo de Oliveira; Ueda-Nakamura, Tânia; Silva, Sueli Oliveira

    2012-01-01

    Here we demonstrate the activity of geranylgeraniol, the major bioactive constituent from seeds of Bixa orellana, against Leishmania amazonensis. Geranylgeraniol was identified through 1H and 13C nuclear magnetic resonance imaging and DEPT. The compound inhibited the promastigote and intracellular amastigote forms, with IC50 of 11 ± 1.0 and 17.5 ± 0.7 μg/mL, respectively. This compound was also more toxic to parasites than to macrophages and did not cause lysis in human blood cells. Morphological and ultrastructural changes induced by geranylgeraniol were observed in the protozoan by electronic microscopy and included mainly mitochondria alterations and an abnormal chromatin condensation in the nucleus. These alterations were confirmed by Rh 123 and TUNEL assays. Additionally, geranylgeraniol induces an increase in superoxide anion production. Collectively, our in vitro studies indicate geranylgeraniol as a selective antileishmanial that appears to be mediated by apoptosis-like cell death. PMID:23304195

  15. Hydrogen peroxide-independent generation of superoxide catalyzed by soybean peroxidase in response to ferrous ion.

    PubMed

    Kimura, Makoto; Kawano, Tomonori

    2015-01-01

    It is well documented that extracellular alkalization occurs in plants under the challenges by pathogenic microbes. This may eventually induce the pH-dependent extracellular peroxidase-mediated oxidative burst at the site of microbial challenges. By employing the purified proteins of horseradish peroxidase as a model, we have recently proposed a likely role for free Fe(2+) in reduction of ferric enzyme of plant peroxidases into ferrous intermediate and oxygen-bound form of enzyme known as Compound III which may eventually releases superoxide anion radical (O2(•-)), especially under alkaline condition, possibly contributing to the plant defense mechanism. In the present study, we employed the purified protein of soybean peroxidase (SBP) as an additional model, and examined the changes in the redox status of enzyme accompanying the generation of O2(•-) in response to Fe(2+) under alkaline condition.

  16. ENVIRONMENTAL EFFECTS ON SUPEROXIDE DISMUTASE AND CATALASE ACTIVITY AND EXPRESSION IN HONEY BEE.

    PubMed

    Nikolić, Tatjana V; Purać, Jelena; Orčić, Snežana; Kojić, Danijela; Vujanović, Dragana; Stanimirović, Zoran; Gržetić, Ivan; Ilijević, Konstantin; Šikoparija, Branko; Blagojević, Duško P

    2015-12-01

    Understanding the cellular stress response in honey bees will significantly contribute to their conservation. The aim of this study was to analyze the response of the antioxidative enzymes superoxide dismutase and catalase in honey bees related to the presence of toxic metals in different habitats. Three locations were selected: (i) Tunovo on the mountain Golija, as control area, without industry and large human impact, (ii) Belgrade as urban area, and (iii) Zajača, as mining and industrial zone. Our results showed that the concentrations of lead (Pb) in whole body of bees vary according to habitat, but there was very significant increase of Pb in bees from investigated industrial area. Bees from urban and industrial area had increased expression of both Sod1 and Cat genes, suggesting adaptation to increased oxidative stress. However, in spite increased gene expression, the enzyme activity of catalase was lower in bees from industrial area suggesting inhibitory effect of Pb on catalase.

  17. The SODyssey: superoxide dismutases from biochemistry, through proteomics, to oxidative stress, aging and nutraceuticals.

    PubMed

    D'Alessandro, Angelo; Zolla, Lello

    2011-06-01

    A total of 40 years have already passed since the pioneering work of McCord and Fridovich on erythrocuprein superoxide dismutase (SOD) activity. This modern scientific 'Odyssey' has been accompanied by a series of successes in the fields of biochemistry, biomedicine and proteomics. In this article, we resume the main strides in these fields, mainly aiming at delivering an exhaustive portrait of SOD's involvement in several oxidative stress-triggered threats to human health, including neurodegenerative disorders (amyotrophic lateral sclerosis, Alzheimer's, Parkinson's and Huntington's diseases), cardiovascular diseases, cancer and aging. In parallel, food-derived chemical compounds appear to be intertwined with cellular redox poise modulation, as this increasingly emerges from clinical biochemical and proteomic investigations. Thus, we will also consider the involvement of these nutraceuticals in oxidative stress-triggered diseases and SOD activity modulation. Like a modern Ulysses, researchers know that the journey is not yet over. Nevertheless, much information has been gathered over the last four decades. PMID:21679120

  18. A study on scavenging effects of Chinese medicine on superoxide anion radicals by pulse radiolysis

    NASA Astrophysics Data System (ADS)

    Fengmei, Li; Andong, Liu; Hongchun, Gu; Shaojie, Di

    1993-10-01

    A study on scavenging and dismutation effects on superoxide anion radical (·O -2) by using two Chinese antiaging medicine-Salvia Miltiorrhiza injection (S.M.) and Sulekang capsule (S.C.) were performed by pulse radiolysis. The absorption spectra of ·O -2 have been redetermined in radiolysis of aqueous solution of sodium format. The absorption maximum is at about 250nm. The results suggested that S.M. and S.C. can dismutate and scavenge ·O -2. The experimental scavenging rate of S.M. (150μg/ml) and S.C. (250μg/ml) were 89.6% and 69.5% respectively.

  19. Catalase and superoxide dismutase activities after heat injury of listeria monocytogenes

    SciTech Connect

    Dallmier, A.W.; Martin, S.E.

    1988-02-01

    Four strains of Listeria monocytogenes were examined for catalase (CA) and superoxide dismutase (SOD) activities. The two strains having the highest CA activities (LCDC and Scott A) also possessed the highest SOD activities. The CA activity of heated cell extracts of all four strains examined decreased sharply between 55 and 60/sup 0/C. SOD was more heat labile than CA. Two L. monocytogenes strains demonstrated a decline in SOD activity after heat treatment at 45/sup 0/C, whereas the other two strains demonstrated a decline at 50/sup 0/C. Sublethal heating of the cells at 55/sup 0/C resulted in increased sensitivity to 5.5% NaCl. Exogenous hydrogen peroxide was added to suspensions of L. monocytogenes; strains producing the highest CA levels showed the greatest H/sub 2/O/sub 2/ resistance.

  20. PEA chloroplasts under clino-rotation: lipid peroxidation and superoxide dismutase activity

    NASA Astrophysics Data System (ADS)

    Baranenko, V. V.

    The lipid peroxidation (LP) intensity and the activity of the antioxidant enzyme superoxide dismutase (SOD) were studied in chloroplasts of pea (Pisum sativum L.) plants grown for 7 and 14 days under clino-rotation. An increase in LP levels in chloroplasts during both terms of clinorotation in comparison with stationary controls was documented. SOD activity increased in chloroplasts of plants that were clino-rotated for seven days. SOD has a significant protective effect by diminishing the availability of O2-. However, under more prolonged clino-rotation (14 days), SOD activity decreased but was still higher than in the control samples. In accordance with Selye's oxidative stress theory (Selye, 1956; modified by Leshem et al., 1998), plants that were clino-rotated for seven days are presumed to be in a stage of resistance while 14-day plants reached a stage of exhaustion.

  1. Dammarane triterpene saponin from Bacopa monniera as the superoxide inhibitor in polymorphonuclear cells.

    PubMed

    Pawar, R; Gopalakrishnan, C; Bhutani, K K

    2001-11-01

    The hydroalcoholic extract of the whole plant of Bacopa monniera Wettst. (Scrophulariaceae), exhibited an inhibitory effect on superoxide released from polymorphonuclear (PMN) cells in the nitroblue tetrazolium (NBT) assay. The major saponin bacoside A(3) was found to be responsible for this effect in the herb. This compound showed 85, 91.66, 91.66, and 83 % inhibitions of NBT reduction at the concentrations of 200, 100, 50, and 25 microg/ml, respectively, with an IC(50) value of 10.22 microg/ml. These inhibitory effects were compared with those of the standard positive controls, quercetin and ascorbic acid with IC(50) of 111 and 14.16 microg/ml, respectively. Another major saponin bacopasaponin C was found to be much less potent as compared to bacoside A(3) whereas the remaining two mixtures of saponins were found to be inactive.

  2. Effect of lu-duo-wei on scavenging superoxide and hydroxyl radicals in vitro.

    PubMed

    Fang, Y Z; Sun, C P; Tian, X H; Cong, J H

    1998-01-01

    Irradiation of a riboflavin-containing system by ultraviolet light was used to produce superoxide radical (.O2-). Hydroxyl radical (.OH) was generated by the system of Fe(II)-H2O2. Using electron spin resonance and spin trapping techniques, the effect of Lu-Duo-Wei, a capsule consisting extracts of green tea, Fructus Lycii and Semen Ziziphi Spinosae, on scavenging .O2- and .OH was observed. The results showed that the efficiency of scavenging .O2- and .OH by Lu-Duo-Wei was much higher than that by tea polyphenol alone. It is suggested that the synergistic action of tea polyphenol and other components are responsible for the scavenging effect of Lu-Duo-Wei on .O2- and .OH. PMID:9799967

  3. 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

  4. Genetics of superoxide dismutase in the forest tent caterpillar and other organisms.

    PubMed

    Lorimer, N

    1979-01-01

    The electrophoretic assay of superoxide dismutase (SOD) in Malacosoma disstria revealed a total of 13 bands arranged in 9 patterns. One locus, composed of bands 28, 32, 36 was polymorphic in some locations. Band frequencies varied by location, but not by generation or by time in the laboratory. Significant interactions between sibling groups and SOD types for development time suggest that selective advantage is a function of genetic background. SOD, an important enzyme protecting diverse organisms against the toxic radicals of oxygen, has been extensively analyzed by biochemists. Geneticists have assayed individuals and populations for the smae enzyme, calling it tetrazolium oxidase (TO). The biochemistry and genetics literatures were reviewed and results from the two disciplines were discussed.

  5. Production and removal of superoxide anion radical by artificial metalloenzymes and redox-active metals.

    PubMed

    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

  6. Molecular mechanism on cadmium-induced activity changes of catalase and superoxide dismutase.

    PubMed

    Wang, Jing; Zhang, Hao; Zhang, Tong; Zhang, Rui; Liu, Rutao; Chen, Yadong

    2015-01-01

    Cadmium contributes to adverse effects of organisms probably because of its ability to induce oxidative stress via alterations in activities of antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD), but their molecular mechanisms remain unclear. We investigated the molecular mechanism of CAT and SOD response under Cd-induced oxidative stress in the liver of zebrafish. The enzyme activity changes observed in vitro were consistent with those seen in vivo, indicating the direct interaction of CAT and SOD with Cd contributes to their activity change in vivo. Further experiments utilizing multiple spectroscopic methods, isothermal titration calorimetry and a molecular docking study were performed to explore the mechanism of molecular interaction of CAT and SOD with Cd. Different interaction patterns were found that resulted in misfolding and changed the enzyme activities. Taken together, we suggest the misfolding of CAT and SOD contributes to their activity change under Cd-induced oxidative stress in vivo.

  7. Molecular cloning of an Onchocerca volvulus extracellular Cu-Zn superoxide dismutase.

    PubMed Central

    James, E R; McLean, D C; Perler, F

    1994-01-01

    Onchocerca volvulus, a human parasitic nematode, is the third leading cause of preventable blindness worldwide. This study describes the molecular cloning of a novel superoxide dismutase (SOD) from the parasite. This putative O. volvulus extracellular SOD (OvEcSOD) is 628 nucleotides (nt) long, including a 22-nt 5' spliced leader (SL1) and a portion encoding an N-terminal hydrophobic 42-amino-acid signal peptide. The remainder of the cDNA shares 71% identity with an O. volvulus cytosolic SOD sequence and is 3 nt longer. All residues involved in metal ion binding, active site formation, folding, and dimer formation in SODs are conserved. Data indicate the OvEcSOD and O. volvulus cytosolic SOD are separate gene products and that the OvEcSOD appears to possess the characteristics of a membrane-bound or secreted enzyme which may be involved in the parasite defense against phagocyte-generated reactive oxygen species. Images PMID:8300230

  8. Carotenoids can act as antioxidants by oxidizing the superoxide radical anion.

    PubMed

    Galano, Annia; Vargas, Rubicelia; Martínez, Ana

    2010-01-01

    The electron transfer (ET) reaction between carotenoids and the superoxide radical anion is found to be not only a viable process but also a very unique one. The nature of the O(2) (-) inverts the direction of the transfer, with respect to ET involving other ROS: the O(2) (-) becomes the electron donor and carotenoids (CAR) the electron acceptor. Therefore the "antioxidant" activity of CAR when reacting with O(2) (-) lies in their capacity to prevent the formation of oxidant ROS. This peculiar charge transfer is energetically feasible in non-polar environments but not in polar media. In addition the relative reactivity of CAR towards O(2) (-) is drastically different from their reactivity to other ROS. Asthaxanthin (ASTA) is predicted to be a better O(2) (-) quencher than LYC and the other CAR. The CAR + O(2) (-) reactions were found to be diffusion controlled. The agreement with available experimental data supports the density functional theory results from the present work. PMID:20024459

  9. Therapeutic value of oral supplementation with melon superoxide dismutase and wheat gliadin combination.

    PubMed

    Romao, Susana

    2015-03-01

    Dietary antioxidant supplementation has been popular in Western countries. Various supplements have been developed in recent years, and research has been gathered from both animal and clinical research trials. In this review, the therapeutic value of oral administration of a combination of melon superoxide dismutase (SOD) and a vegetable polymer (gliadin) is evaluated. Critical examination of the effects of SOD-gliadin supplementation is carried out, with an emphasis on its impact on oxidative stress levels and on endogenous antioxidant pathways. Overall analysis of peer-reviewed published data suggests that intake of SOD-gliadin might have advantageous health effects. These conclusions are dependent on the condition or pathology under consideration. In general, the authors, who analyzed SOD-gliadin supplementation, support the use of SOD-gliadin supplementation as a complementary treatment rather than a therapeutic treatment. To further clarify the importance of dietary SOD-gliadin administration, additional large-scale clinical trials are recommended.

  10. Cloning and expression of an iron-containing superoxide dismutase in the parasitic protist, Trichomonas vaginalis.

    PubMed

    Viscogliosi, E; Delgado-Viscogliosi, P; Gerbod, D; Dauchez, M; Gratepanche, S; Alix, A J; Dive, D

    1998-04-01

    A superoxide dismutase (SOD) gene of the parasitic protist Trichomonas vaginalis was cloned, sequenced, expressed in Escherichia coli, and its gene product characterized. It is an iron-containing dimeric protein with a monomeric mass of 22,067 Da. Southern blots analyses suggested the presence of seven iron-containing (FeSOD) gene copies. Hydrophobic cluster analysis revealed some peculiarities in the 2D structure of the FeSOD from T. vaginalis and a strong structural conservation between prokaryotic and eukaryotic FeSODs. Phylogenetic reconstruction of the SOD sequences confirmed the dichotomy between FeSODs and manganese-containing SODs. FeSODs of protists appeared to group together with homologous proteobacterial enzymes suggesting a possible origin of eukaryotic FeSODs through an endosymbiotic event.

  11. Mitochondria Superoxide Anion Production Contributes to Geranylgeraniol-Induced Death in Leishmania amazonensis.

    PubMed

    Lopes, Milene Valéria; Desoti, Vânia Cristina; Caleare, Angelo de Oliveira; Ueda-Nakamura, Tânia; Silva, Sueli Oliveira; Nakamura, Celso Vataru

    2012-01-01

    Here we demonstrate the activity of geranylgeraniol, the major bioactive constituent from seeds of Bixa orellana, against Leishmania amazonensis. Geranylgeraniol was identified through (1)H and (13)C nuclear magnetic resonance imaging and DEPT. The compound inhibited the promastigote and intracellular amastigote forms, with IC(50) of 11 ± 1.0 and 17.5 ± 0.7 μg/mL, respectively. This compound was also more toxic to parasites than to macrophages and did not cause lysis in human blood cells. Morphological and ultrastructural changes induced by geranylgeraniol were observed in the protozoan by electronic microscopy and included mainly mitochondria alterations and an abnormal chromatin condensation in the nucleus. These alterations were confirmed by Rh 123 and TUNEL assays. Additionally, geranylgeraniol induces an increase in superoxide anion production. Collectively, our in vitro studies indicate geranylgeraniol as a selective antileishmanial that appears to be mediated by apoptosis-like cell death. PMID:23304195

  12. Activity of superoxide dismutase and catalase in the bean weevil (Acanthoscelides obtectus) selected for postponed senescence.

    PubMed

    Seslija, D; Blagojević, D; Spasić, M; Tucić, N

    1999-04-01

    Relationship of superoxide dismutase and catalase activities and aging were tested using bean weevil lines selected for postponed senescence. The beetles of different age (young and old) and mating status (virgin and mated) from the extended longevity lines were compared with their counterparts derived from the short-lived lines for activities of SOD and catalase. The old beetles from the long-lived lines had statistically significant higher activity of SOD than their controls. Although we did not find a significant effect of catalase on longevity, beetles originating from both types of lines exhibited an increased catalase activity during mating processes. In addition, we did observe an increased activity of catalase in one-day-old beetles of the short-lived lines relative to the same-aged individuals of the long-lived lines.

  13. Screening for Intestinal Microflora Influencing Superoxide Dismutase Activity in Mouse Cecal Mucosa

    PubMed Central

    DOBASHI, Yuu; ITOH, Kikuji; TOHEI, Atsushi; AMAO, Hiromi

    2013-01-01

    ABSTRACT We have suggested that intestinal microflora reduces the activity of the antioxidant enzyme superoxide dismutase (SOD) in the mouse cecal mucosa. In this study, gnotobiotic mice were used to examine the species of intestinal microflora influencing SOD activity in the cecal mucosa. The total SOD activity in the cecal mucosa of each germ-free (GF), gnotobiotic mouse with Escherichia coli, Lactobacillus and Bacteroides was significantly higher than that in the cecal mucosa of gnotobiotic mice with chloroform-treated feces (CHF), conventionalized (CVz) mice and conventional (CV) mice (P<0.05). In addition, CuZnSOD mRNA expression showed similar tendencies. Our results suggest that the antioxidant defense status in the cecal mucosa is influenced by CHF inoculation. PMID:24225363

  14. Qualitative Determination of Superoxide Release at Both Sides of the Mitochondrial Inner Membrane by Capillary Electrophoretic Analysis of the Oxidation Products of Triphenylphosphonium Hydroethidine*

    PubMed Central

    Xu, Xin; Arriaga, Edgar A.

    2009-01-01

    Superoxide is released asymmetrically to both sides of the mitochondrial inner membrane. Since this membrane is impermeable to superoxide, two separate pools are formed at either side of the membrane, each with its own characteristics and potential biological effects. Here, we report an attomole-sensitive fast capillary electrophoretic method that can analyze superoxide in a single pool, either the matrix pool or that outside the mitochondria. The method uses triphenylphosphonium hydroethidine (TPP-HE) that reacts with the superoxide in both pools. Centrifugation is used to separate the mitochondria (i.e. matrix contents) from the supernatant (i.e. products released outside the mitochondria). Each fraction is then analyzed by a capillary electrophoresis with laser-induced fluorescence detection (CE-LIF) method that separates and detects hydroxytriphenylphosphonium ethidium (OH-TPP-E+), the fluorescent superoxide specific product. The separation takes < 3 min and the detection level is down to 3 attomole OH-TPP-E+. The method has proved to be effective detecting qualitatively superoxide release in the mitochondria of 143B cells, mouse liver, and rat skeletal muscle, both in the presence and absence of inhibitors. In addition, this study confirmed that Complex I releases superoxide only toward the matrix while Complex III releases superoxide toward both sides of the mitochondrial inner membrane. Furthermore, treatment with menadione induces superoxide release toward both sides of the mitochondrial inner membrane. PMID:19168125

  15. The requirement for membrane sialic acid in the stimulation of superoxide production during phagocytosis by human polymorphonuclear leukocytes

    PubMed Central

    1976-01-01

    The effect of desialylation on phagocytosis of latex particles and oxidative metabolism of human polymorphonuclear leukocytes was studied. Removal of 20% total leukocyte sialic acid by bacterial neuraminidase had no effect on phagocytosis of latex particles and phagocytosis- associated activation of hexose monophosphate shunt in human polymorphonuclear leukocytes. In contrast, desialylation prevented the stimulation of superoxide production either by phagocytosis or by concanavalin A. It is concluded that membrane sialic acid is essential for the stimulation of superoxide production by human polymorphonuclear leukocytes. PMID:178821

  16. The superoxide-generating NADPH oxidase of human neutrophils is electrogenic and associated with an H+ channel.

    PubMed Central

    Henderson, L M; Chappell, J B; Jones, O T

    1987-01-01

    The membrane potential of cytoplasts, derived from human neutrophils, was depolarized by the activation of the superoxide-generating NADPH-dependent oxidase. The extent of the depolarization was inhibited by diphenylene iodonium and was therefore due directly to the activity of the oxidase, which must be electrogenic. The extent of the depolarization was influenced by alteration of the delta pH across the cytoplast membrane, indicating that the outward translocation of H+ eventually compensates for superoxide generation. The depolarization of the potential is enhanced by Cd2+, a blocker of H+ currents, suggesting that the compensatory movement is via an H+ channel. PMID:2825632

  17. Progress in Understanding Algal Bloom-Mediated Fish Kills: The Role of Superoxide Radicals, Phycotoxins and Fatty Acids

    PubMed Central

    Dorantes-Aranda, Juan José; Seger, Andreas; Mardones, Jorge I.; Nichols, Peter D.; Hallegraeff, Gustaaf M.

    2015-01-01

    Quantification of the role of reactive oxygen species, phycotoxins and fatty acids in fish toxicity by harmful marine microalgae remains inconclusive. An in vitro fish gill (from rainbow trout Oncorhynchus mykiss) assay was used to simultaneously assess the effect in superoxide dismutase, catalase and lactate dehydrogenase enzymatic activities caused by seven species of ichthyotoxic microalgae (Chattonella marina, Fibrocapsa japonica, Heterosigma akashiwo, Karenia mikimotoi, Alexandrium catenella, Karlodinium veneficum, Prymnesium parvum). Quantification of superoxide production by these algae was also performed. The effect of purified phycotoxins and crude extracts was compared, and the effect of fatty acids is discussed. The raphidophyte Chattonella was the most ichthyotoxic (gill cell viability down to 35%) and also the major producer of superoxide radicals (14 pmol cell-1 hr-1) especially after cell lysis. The raphidophyte Heterosigma and dinoflagellate Alexandrium were the least toxic and had low superoxide production, except when A. catenella was lysed (5.6 pmol cell-1 hr-1). Catalase showed no changes in activity in all the treatments. Superoxide dismutase (SOD) and lactate dehydrogenase exhibited significant activity increases of ≤23% and 51.2% TCC (total cellular content), respectively, after exposure to C. marina, but SOD showed insignificant changes with remaining algal species. A strong relationship between gill cell viability and superoxide production or superoxide dismutase was not observed. Purified brevetoxins PbTx-2 and -3 (from Karenia brevis, LC50 of 22.1 versus 35.2 μg mL-1) and karlotoxin KmTx-2 (from Karlodinium; LC50 = 380 ng mL-1) could almost entirely account for the fish killing activity by those two dinoflagellates. However, the paralytic shellfish toxins (PST) GTX1&4, C1&C2, and STX did not account for Alexandrium ichthyotoxicity. Only aqueous extracts of Alexandrium were cytotoxic (≤65% decrease of viability), whereas crude

  18. Quantification of superoxide radical production in thylakoid membrane using cyclic hydroxylamines.

    PubMed

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

    2015-12-01

    Applicability of two lipophilic cyclic hydroxylamines (CHAs), CM-H and TMT-H, and two hydrophilic CHAs, CAT1-H and DCP-H, for detection of superoxide anion radical (O2(∙-)) produced by the thylakoid photosynthetic electron transfer chain (PETC) of higher plants under illumination has been studied. ESR spectrometry was applied for detection of the nitroxide radical originating due to CHAs oxidation by O2(∙-). CHAs and corresponding nitroxide radicals were shown to be involved in side reactions with PETC which could cause miscalculation of O2(∙-) production rate. Lipophilic CM-H was oxidized by PETC components, reducing the oxidized donor of Photosystem I, P700(+), while at the same concentration another lipophilic CHA, TMT-H, did not reduce P700(+). The nitroxide radical was able to accept electrons from components of the photosynthetic chain. Electrostatic interaction of stable cation CAT1-H with the membrane surface was suggested. Water-soluble superoxide dismutase (SOD) was added in order to suppress the reaction of CHA with O2(∙-) outside the membrane. SOD almost completely inhibited light-induced accumulation of DCP(∙), nitroxide radical derivative of hydrophilic DCP-H, in contrast to TMT(∙) accumulation. Based on the results showing that change in the thylakoid lumen pH and volume had minor effect on TMT(∙) accumulation, the reaction of TMT-H with O2(∙-) in the lumen was excluded. Addition of TMT-H to thylakoid suspension in the presence of SOD resulted in the increase in light-induced O2 uptake rate, that argued in favor of TMT-H ability to detect O2(∙-) produced within the membrane core. Thus, hydrophilic DCP-H and lipophilic TMT-H were shown to be usable for detection of O2(∙-) produced outside and within thylakoid membranes.

  19. Eugenol protects nicotine-induced superoxide mediated oxidative damage in murine peritoneal macrophages in vitro.

    PubMed

    Kar Mahapatra, Santanu; Chakraborty, Subhankari Prasad; Majumdar, Subrata; Bag, Braja Gopal; Roy, Somenath

    2009-11-25

    The present work is aimed at evaluating the protective effect of eugenol against in vitro nicotine-induced toxicity in murine peritoneal macrophages, compared with N-acetylcysteine. Eugenol was isolated from Ocimum gratissimum and characterized by HPLC, FTIR, (1)H NMR. To establish most effective protective support, we used five different concentrations of eugenol (1, 5, 10, 15, and 20microg/ml) and N-acetylcysteine (0.25, 0.5, 1.0, 2.0, and 5.0microg/ml) against 10mM nicotine in mice peritoneal macrophages. A dose-dependent protective effect was observed with all doses of eugenol and N-acetylcysteine, as evidenced by decreased level of superoxide anion generation and malondialdehyde, and also increased level of reduced glutathione, and superoxide dismutase activity. Moreover, maximum protection was observed at the concentration of 15.0microg/ml eugenol (0.09nM) and 1.0microg/ml N-acetylcysteine (0.006nM). Further, eugenol (15.0microg/ml) and N-acetylcysteine (1.0microg/ml) were tested against nicotine (10mM) toxicity by analyzing the radical generation, lipid, protein, DNA damage, and endogenous antioxidant status. There was a significant increase in the level of radical generation, NADPH oxidase and myeloperoxidase activity, lipid, protein, DNA damage and oxidized glutathione level in nicotine-treated group, which were significantly reduced by eugenol and N-acetylcysteine supplementation. Antioxidant status was significantly depleted in the nicotine-treated group, which was effectively restored by eugenol and N-acetylcysteine supplementation. The protection by eugenol against nicotine toxicity was merely equal effective to that of N-acetylcysteine. These findings suggest the potential use and benefit of eugenol isolated from O. gratissimum as a modulator of nicotine-induced cellular damage and it may be used as an immunomodulatory drug against nicotine toxicity.

  20. Identification and Analysis of the Role of Superoxide Dismutases Isoforms in the Pathogenesis of Paracoccidioides spp.

    PubMed Central

    Tamayo, Diana; Muñoz, José F.; Lopez, Ángela; Urán, Martha; Herrera, Juan; Borges, Clayton L.; Restrepo, Ángela; Soares, Celia M.; Taborda, Carlos P.; Almeida, Agostinho J.; McEwen, Juan G.; Hernández, Orville

    2016-01-01

    The ability of Paracoccidioides to defend itself against reactive oxygen species (ROS) produced by host effector cells is a prerequisite to survive. To counteract these radicals, Paracoccidioides expresses, among different antioxidant enzymes, superoxide dismutases (SODs). In this study, we identified six SODs isoforms encoded by the Paracoccidioides genome. We determined gene expression levels of representative isolates of the phylogenetic lineages of Paracoccidioides spp. (S1, PS2, PS3 and Pb01-like) using quantitative RT-PCR. Assays were carried out to analyze SOD gene expression of yeast cells, mycelia cells, the mycelia-to-yeast transition and the yeast-to-mycelia germination, as well as under treatment with oxidative agents and during interaction with phagocytic cells. We observed an increased expression of PbSOD1 and PbSOD3 during the transition process, exposure to oxidative agents and interaction with phagocytic cells, suggesting that these proteins could assist in combating the superoxide radicals generated during the host-pathogen interaction. Using PbSOD1 and PbSOD3 knockdown strains we showed these genes are involved in the response of the fungus against host effector cells, particularly the oxidative stress response, and in a mouse model of infection. Protein sequence analysis together with functional analysis of knockdown strains seem to suggest that PbSOD3 expression is linked with a pronounced extracellular activity while PbSOD1 seems more related to intracellular requirements of the fungus. Altogether, our data suggests that P. brasiliensis actively responds to the radicals generated endogenously during metabolism and counteracts the oxidative burst of immune cells by inducing the expression of SOD isoforms. PMID:26963091

  1. Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

    NASA Astrophysics Data System (ADS)

    Liu, Jianguo; Zhang, Xiaoli; Sun, Yanhong; Lin, Wei

    2010-01-01

    The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O{2/-}). The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H. pluvialis during exposure to reactive oxygen species (ROS) such as O{2/-}. Astaxanthin reacted with ROS much faster than did the protective enzymes, and had the strongest antioxidative capacity to protect against lipid peroxidation. The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells. Astaxanthin-enriched red cells had the strongest antioxidative capacity, followed by brown cells, and astaxanthin-deficient green cells. Although there was no significant increase in expression of protective enzymes, the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin, which quenched O{2/-} before the protective enzymes could act. In green cells, astaxanthin is very low or absent; therefore, scavenging of ROS is inevitably reliant on antioxidative enzymes. Accordingly, in green cells, these enzymes play the leading role in scavenging ROS, and the expression of these enzymes is rapidly increased to reduce excessive ROS. However, because ROS were constantly increased in this study, the enhance enzyme activity in the green cells was not able to repair the ROS damage, leading to elevated MDA content. Of the four defensive enzymes measured in astaxanthin-deficient green cells, SOD eliminates O{2/-}, POD eliminates H2O2, which is a by-product of SOD activity, and APX and CAT are then initiated to scavenge excessive ROS.

  2. Eugenol protects nicotine-induced superoxide mediated oxidative damage in murine peritoneal macrophages in vitro.

    PubMed

    Kar Mahapatra, Santanu; Chakraborty, Subhankari Prasad; Majumdar, Subrata; Bag, Braja Gopal; Roy, Somenath

    2009-11-25

    The present work is aimed at evaluating the protective effect of eugenol against in vitro nicotine-induced toxicity in murine peritoneal macrophages, compared with N-acetylcysteine. Eugenol was isolated from Ocimum gratissimum and characterized by HPLC, FTIR, (1)H NMR. To establish most effective protective support, we used five different concentrations of eugenol (1, 5, 10, 15, and 20microg/ml) and N-acetylcysteine (0.25, 0.5, 1.0, 2.0, and 5.0microg/ml) against 10mM nicotine in mice peritoneal macrophages. A dose-dependent protective effect was observed with all doses of eugenol and N-acetylcysteine, as evidenced by decreased level of superoxide anion generation and malondialdehyde, and also increased level of reduced glutathione, and superoxide dismutase activity. Moreover, maximum protection was observed at the concentration of 15.0microg/ml eugenol (0.09nM) and 1.0microg/ml N-acetylcysteine (0.006nM). Further, eugenol (15.0microg/ml) and N-acetylcysteine (1.0microg/ml) were tested against nicotine (10mM) toxicity by analyzing the radical generation, lipid, protein, DNA damage, and endogenous antioxidant status. There was a significant increase in the level of radical generation, NADPH oxidase and myeloperoxidase activity, lipid, protein, DNA damage and oxidized glutathione level in nicotine-treated group, which were significantly reduced by eugenol and N-acetylcysteine supplementation. Antioxidant status was significantly depleted in the nicotine-treated group, which was effectively restored by eugenol and N-acetylcysteine supplementation. The protection by eugenol against nicotine toxicity was merely equal effective to that of N-acetylcysteine. These findings suggest the potential use and benefit of eugenol isolated from O. gratissimum as a modulator of nicotine-induced cellular damage and it may be used as an immunomodulatory drug against nicotine toxicity. PMID:19769960

  3. Identification and Analysis of the Role of Superoxide Dismutases Isoforms in the Pathogenesis of Paracoccidioides spp.

    PubMed

    Tamayo, Diana; Muñoz, José F; Lopez, Ángela; Urán, Martha; Herrera, Juan; Borges, Clayton L; Restrepo, Ángela; Soares, Celia M; Taborda, Carlos P; Almeida, Agostinho J; McEwen, Juan G; Hernández, Orville

    2016-03-01

    The ability of Paracoccidioides to defend itself against reactive oxygen species (ROS) produced by host effector cells is a prerequisite to survive. To counteract these radicals, Paracoccidioides expresses, among different antioxidant enzymes, superoxide dismutases (SODs). In this study, we identified six SODs isoforms encoded by the Paracoccidioides genome. We determined gene expression levels of representative isolates of the phylogenetic lineages of Paracoccidioides spp. (S1, PS2, PS3 and Pb01-like) using quantitative RT-PCR. Assays were carried out to analyze SOD gene expression of yeast cells, mycelia cells, the mycelia-to-yeast transition and the yeast-to-mycelia germination, as well as under treatment with oxidative agents and during interaction with phagocytic cells. We observed an increased expression of PbSOD1 and PbSOD3 during the transition process, exposure to oxidative agents and interaction with phagocytic cells, suggesting that these proteins could assist in combating the superoxide radicals generated during the host-pathogen interaction. Using PbSOD1 and PbSOD3 knockdown strains we showed these genes are involved in the response of the fungus against host effector cells, particularly the oxidative stress response, and in a mouse model of infection. Protein sequence analysis together with functional analysis of knockdown strains seem to suggest that PbSOD3 expression is linked with a pronounced extracellular activity while PbSOD1 seems more related to intracellular requirements of the fungus. Altogether, our data suggests that P. brasiliensis actively responds to the radicals generated endogenously during metabolism and counteracts the oxidative burst of immune cells by inducing the expression of SOD isoforms. PMID:26963091

  4. Peroxiredoxin 6 (Prdx6) supports NADPH oxidase1 (Nox1)-based superoxide generation and cell migration.

    PubMed

    Kwon, Jaeyul; Wang, Aibing; Burke, Devin J; Boudreau, Howard E; Lekstrom, Kristen J; Korzeniowska, Agnieszka; Sugamata, Ryuichi; Kim, Yong-Soo; Yi, Liang; Ersoy, Ilker; Jaeger, Stefan; Palaniappan, Kannappan; Ambruso, Daniel R; Jackson, Sharon H; Leto, Thomas L

    2016-07-01

    Nox1 is an abundant source of reactive oxygen species (ROS) in colon epithelium recently shown to function in wound healing and epithelial homeostasis. We identified Peroxiredoxin 6 (Prdx6) as a novel binding partner of Nox activator 1 (Noxa1) in yeast two-hybrid screening experiments using the Noxa1 SH3 domain as bait. Prdx6 is a unique member of the Prdx antioxidant enzyme family exhibiting both glutathione peroxidase and phospholipase A2 activities. We confirmed this interaction in cells overexpressing both proteins, showing Prdx6 binds to and stabilizes wild type Noxa1, but not the SH3 domain mutant form, Noxa1 W436R. We demonstrated in several cell models that Prdx6 knockdown suppresses Nox1 activity, whereas enhanced Prdx6 expression supports higher Nox1-derived superoxide production. Both peroxidase- and lipase-deficient mutant forms of Prdx6 (Prdx6 C47S and S32A, respectively) failed to bind to or stabilize Nox1 components or support Nox1-mediated superoxide generation. Furthermore, the transition-state substrate analogue inhibitor of Prdx6 phospholipase A2 activity (MJ-33) was shown to suppress Nox1 activity, suggesting Nox1 activity is regulated by the phospholipase activity of Prdx6. Finally, wild type Prdx6, but not lipase or peroxidase mutant forms, supports Nox1-mediated cell migration in the HCT-116 colon epithelial cell model of wound closure. These findings highlight a novel pathway in which this antioxidant enzyme positively regulates an oxidant-generating system to support cell migration and wound healing. PMID:27094494

  5. Complement and immunoglobulins stimulate superoxide production by human leukocytes independently of phagocytosis.

    PubMed Central

    Goldstein, I M; Roos, D; Kaplan, H B; Weissmann, G

    1975-01-01

    Human peripheral blood polymorphonuclear leukocytes, when exposed to appropriate stimuli, generate significant amounts of superoxide anion (O-.2), a highly reactive molecule which is possibly involved in bacterial killing. Since the subcellular localization and mechanism of activation of O-.2 generating systems are unknown, we have investigated superoxide dismutase-inhibitable cytochrome c reduction (attributable to O-.2) by, and lysosomal enzyme release from, normal polymorphonuclear leukocytes and cells rendered incapable of ingesting particles by treatment with cytochalasin B. Neither phagocytosis nor lysosomal degranulation were prerequisites for enhanced O-.2 generation. Cytochalasin B-treated cells exposed to (a) serum-treated zymosan, a C3b receptor stimulus; (b) heat aggregated human IgG, an Fc receptor stimulus; and (c) the complement component, C5a, generated enhanced amounts of O-.2 in a time and concentration-dependent fashion. These cells also responded by releasing lysosomal enzymes, but there was no correlation between the ability of any immune reactant to provoke enzyme release and its ability to stimulate O-.2 generation. The three stimuli also enhanced O-.2 generation by normal (untreated) polymorphonuclear leukocytes, but only serum-treated zymosan and aggregated IgG were capable of provoking lysosomal enzyme release from normal cells. Untreated zymosan and native IgG neither stimulated O-.2 production nor provoked lysomal enzyme release. Since enhanced O-.2 production was stimulated by immune reactants in the absence of phagocytosis, the O-.2 generating system is very likely associated with the external plasma membrane of the polymorphonuclear leukocyte. Leukocyte membrane receptors for complement and immunoglobulins may therefore not only serve in particle recognition but also may initiate biochemical events which accompany phagocytosis and killing. PMID:171281

  6. Roles of exogenous divalent metals in the nucleolytic activity of Cu,Zn superoxide dismutase.

    PubMed

    Jiang, Wei; Han, Yingchun; Pan, Qunhui; Shen, Tao; Liu, Changlin

    2007-04-01

    It is well known that the wild type Cu,Zn superoxide dismutase (holo SOD) catalyzes the conversion of superoxide anion to peroxide hydrogen and dioxygen. However, a new function of holo SOD, i.e., nucleolytic activity has been found [W. Jiang, T. Shen, Y. Han, Q. Pan, C. Liu, J. Biol. Inorg. Chem. 11 (2006) 835-848], which is linked to the incorporation of exogenous divalent metals into the enzyme-DNA complex. In this study, the roles of exogenous divalent metals in the nucleolytic activity were explored in detail by a series of biochemical experiments. Based on a non-equivalent multi-site binding model, affinity of a divalent metal for the enzyme-DNA complex was determined by absorption titration, indicating that the complex can provide at least a high and a low affinity site for the metal ion. These mean that the holo SOD may use a "two exogenous metal ion pathway" as a mechanism in which both metal ions are directly involved in the catalytic process of DNA cleavage. In addition, the pH versus DNA cleavage rate profiles can be fitted to two ionizing-group models, indicating the presence of a general acid and a general base in catalysis. A model that requires histidine residues, metal-bound water molecules and two hydrated metal ions to operate in concert could be used to interpret the catalysis of DNA hydrolysis, supported by the dependences of loss of the nucleolytic activity on time and on the concentration of the specific chemical modifier to the histidine residues on the enzyme. PMID:17292965

  7. Adaptive antioxidant response of manganese-superoxide dismutase following repetitive UVA irradiation.

    PubMed

    Poswig, A; Wenk, J; Brenneisen, P; Wlaschek, M; Hommel, C; Quel, G; Faisst, K; Dissemond, J; Briviba, K; Krieg, T; Scharffetter-Kochanek, K

    1999-01-01

    In response to the attack of reactive oxygen species, the skin has developed a complex antioxidant defense system including among others the manganese-superoxide dismutase (MnSOD). MnSOD dismutates the superoxide anion (O2*-) derived from the reduction of molecular oxygen to hydrogen peroxide (H2O2), which is detoxified by glutathione peroxidase to water and molecular oxygen. We have addressed the question whether MnSOD is inducible upon UVA irradiation and whether repetitive UV exposure, as practiced for the light-hardening during phototherapy of various photodermatoses, can even enhance the adaptive antioxidant response. Single exposure of four different strains of fibroblasts to UVA irradiation resulted in a dose- and time-dependent increase in specific MnSOD mRNA levels. Interestingly, repetitive UVA exposure at days 1, 2, and 3 at a dose rate of 200 kJ per m2 resulted in a 5-fold induction of specific MnSOD mRNA levels following the third UVA exposure. Similar results were obtained for MnSOD activity. This adaptive response in terms of upregulation of the antioxidant enzyme MnSOD correlates with the protection against high UV doses, if cells were preexposed to sublethal UV doses. Importantly, MnSOD substantially differed between the tested individuals in both mRNA and activity levels. Taken together, we here provide evidence for the increasing induction of MnSOD upon repetitive UVA irradiation that may contribute to the effective adaptive UVA response of the skin during light hardening in phototherapy. Interindividual differences in the inducibility of MnSOD might account for differences in the susceptibility to develop photodermatologic disorders related to photosensitivity, photoaging, and skin cancer. The molecular basis for interindividual differences in the inducibility of antioxidant enzymes remains to be elucidated. PMID:9886257

  8. Extracellular Superoxide Dismutase Regulates the Expression of Small GTPase Regulatory Proteins GEFs, GAPs, and GDI

    PubMed Central

    Laukkanen, Mikko O.; Cammarota, Francesca; Esposito, Tiziana; Salvatore, Marco; Castellone, Maria D.

    2015-01-01

    Extracellular superoxide dismutase (SOD3), which catalyzes the dismutation of superoxide anions to hydrogen peroxide at the cell membranes, regulates the cellular growth in a dose-dependent manner. This enzyme induces primary cell proliferation and immortalization at low expression levels whereas it activates cancer barrier signaling through the p53-p21 pathway at high expression levels, causing growth arrest, senescence, and apoptosis. Because previous reports suggested that the SOD3–induced reduction in the rates of cellular growth and migration also occurred in the absence of functional p53 signaling, in the current study we investigated the SOD3-induced growth-suppressive mechanisms in anaplastic thyroid cancer cells. Based on our data, the robust over-expression of SOD3 increased the level of phosphorylation of the EGFR, ERBB2, RYK, ALK, FLT3, and EPHA10 receptor tyrosine kinases with the consequent downstream activation of the SRC, FYN, YES, HCK, and LYN kinases. However, pull-down experiments focusing on the small GTPase RAS, RAC, CDC42, and RHO revealed a reduced level of growth and migration signal transduction, such as the lack of stimulation of the mitogen pathway, in the SOD3 over-expressing cells, which was confirmed by MEK1/2 and ERK1/2 Western blotting analysis. Interestingly, the mRNA expression analyses indicated that SOD3 regulated the expression of guanine nucleotide-exchange factors (RHO GEF16, RAL GEF RGL1), GTPase-activating proteins (ARFGAP ADAP2, RAS GAP RASAL1, RGS4), and a Rho guanine nucleotide-disassociation inhibitor (RHO GDI 2) in a dose dependent manner, thus controlling signaling through the small G protein GTPases. Therefore, our current data may suggest the occurrence of dose-dependent SOD3–driven control of the GTP loading of small G proteins indicating a novel growth regulatory mechanism of this enzyme. PMID:25751262

  9. Corroborative models of the cobalt(II) inhibited Fe/Mn superoxide dismutases.

    PubMed

    Scarpellini, Marciela; Wu, Amy J; Kampf, Jeff W; Pecoraro, Vincent L

    2005-07-11

    Attempting to model superoxide dismutase (SOD) enzymes, we designed two new N3O-donor ligands to provide the same set of donor atoms observed in the active site of these enzymes: K(i)Pr2TCMA (potassium 1,4-diisopropyl-1,4,7-triazacyclononane-N-acetate) and KBPZG (potassium N,N-bis(3,5-dimethylpyrazolylmethyl) glycinate). Five new Co(II) complexes (1-5) were obtained and characterized by X-ray crystallography, mass spectrometry, electrochemistry, magnetochemistry, UV-vis, and electron paramagnetic resonance (EPR) spectroscopies. The crystal structures of 1 and 3-5 revealed five-coordinate complexes, whereas complex 2 is six-coordinate. The EPR data of complexes 3 and 4 agree with those of the Co(II)-substituted SOD, which strongly support the proposition that the active site of the enzyme structurally resembles these models. The redox behavior of complexes 1-5 clearly demonstrates the stabilization of the Co(II) state in the ligand field provided by these ligands. The irreversibility displayed by all of the complexes is probably related to an electron-transfer process followed by a rearrangement of the geometry around the metal center for complexes 1 and 3-5 that probably changes from a trigonal bipyramidal (high spin, d7) to octahedral (low spin, d6) as Co(II) is oxidized to Co(III), which is also expected to be accompanied by a spin-state conversion. As the redox potentials to convert the Co(II) to Co(III) are high, it can be inferred that the redox potential of the Co(II)-substituted SOD may be outside the range required to convert the superoxide radical (O2*-) to hydrogen peroxide, and this is sufficient to explain the inactivity of the enzyme. Finally, the complexes reported here are the first corroborative structural models of the Co(II)-substituted SOD.

  10. Involvement of superoxide in ozone-induced airway hyperresponsiveness in anesthetized cats

    SciTech Connect

    Takahashi, T.; Miura, M.; Katsumata, U.; Ichinose, M.; Kimura, K.; Inoue, H.; Takishima, T.; Shirato, K. )

    1993-07-01

    To determine whether oxygen radical scavengers inhibit ozone-induced airway hyperresponsiveness, we examined the protective effect of polyethylene glycol-superoxide dismutase (PEG-SOD) and PEG-catalase (PEG-CAT) on ozone-induced airway hyperresponsiveness in cat airways. Twenty-five cats divided into five groups were anesthetized and mechanically ventilated. There was no difference between the groups in baseline airway responsiveness to inhaled acetylcholine (ACh). In the control group, AChPC, the concentration required to produce a doubling increase in baseline pulmonary resistance, was significantly reduced by ozone exposure (2.0 ppm for 2 h); the ratios of AChPC before ozone exposure to after ozone exposure (AChPC ratio) were 14.8 +/- 5.7 (p < 0.001) and 4.80 +/- 1.6 (p < 0.01) 30 and 120 min after exposure, respectively. Local administration of PEG-SOD (2,000 U/kg) into airways partially but significantly prevented ozone-induced airway hyperresponsiveness. The AChPC ratios were 6.2 +/- 1.4 and 1.5 +/- 0.2 30 and 120 min after exposure, respectively, which were significantly different from those of the control group (p < 0.05), whereas PEG-CAT pretreatment (6,000 U/kg) was without effect. Combined pretreatment with PEG-SOD and PEG-CAT had no additional protective effect compared with PEG-SOD alone. PEG-SOD had no direct effect on airway responsiveness to ACh. These results suggest that superoxide may be involved in ozone-induced airway hyperresponsiveness.

  11. Mitochondrial Dysfunction Due to Lack of Manganese Superoxide Dismutase Promotes Hepatocarcinogenesis

    PubMed Central

    Konzack, Anja; Jakupovic, Mirza; Kubaichuk, Kateryna; Görlach, Agnes; Dombrowski, Frank; Miinalainen, Ilkka; Sormunen, Raija

    2015-01-01

    Abstract Aims: One of the cancer hallmarks is mitochondrial dysfunction associated with oxidative stress. Among the first line of defense against oxidative stress is the dismutation of superoxide radicals, which in the mitochondria is carried out by manganese superoxide dismutase (MnSOD). Accordingly, carcinogenesis would be associated with a dysregulation in MnSOD expression. However, the association studies available so far are conflicting, and no direct proof concerning the role of MnSOD as a tumor promoter or suppressor has been provided. Therefore, we investigated the role of MnSOD in carcinogenesis by studying the effect of MnSOD deficiency in cells and in the livers of mice. Results: We found that loss of MnSOD in hepatoma cells contributed to their conversion toward a more malignant phenotype, affecting all cellular properties generally associated with metabolic transformation and tumorigenesis. In vivo, hepatocyte-specific MnSOD-deficient mice showed changed organ architecture, increased expression of tumor markers, and a faster response to carcinogenesis. Moreover, deficiency of MnSOD in both the in vitro and in vivo model reduced β-catenin and hypoxia-inducible factor-1α levels. Innovation: The present study shows for the first time the important correlation between MnSOD presence and the regulation of two major pathways involved in carcinogenesis, the Wnt/β-catenin and hypoxia signaling pathway. Conclusion: Our study points toward a tumor suppressive role of MnSOD in liver, where the Wnt/β-catenin and hypoxia pathway may be crucial elements. Antioxid. Redox Signal. 23, 1059–1075. PMID:26422659

  12. Cu,Zn-Superoxide Dismutase without Zn is Folded but Catalytically Inactive

    PubMed Central

    Nedd, Sean; Redler, Rachel L.; Proctor, Elizabeth A.; Dokholyan, Nikolay V.; Alexandrova, Anastassia N.

    2014-01-01

    Amyotrophic Lateral Sclerosis has been linked to the gain of aberrant function of superoxide dismutase, Cu,Zn-SOD1 upon protein misfolding. The mechanism of SOD1 misfolding is thought to involve mutations leading to the loss of Zn, followed by protein unfolding, and aggregation. We show that the removal of Zn from SOD1 may not lead to an immediate unfolding, but immediately deactivates the enzyme through a combination of subtle structural and electronic effects. Using Quantum Mechanics/Discrete Molecular Dynamics, we showed that Zn-less wild type SOD1 and its D124N mutant that does not bind Zn both have at least metastable folded states. In those states, the reduction potential of Cu increases, leading to the presence of detectable amounts of Cu(I) instead of Cu(II) in the active site, as confirmed experimentally. The Cu(I) protein cannot participate in the catalytic Cu(I) – Cu(II) cycle. However, even without the full reduction to Cu(I), the Cu site in the Zn-less variants of SOD1 is shown to be catalytically incompetent: unable to bind superoxide in a way comparable to the wild type SOD1. The changes are more radical and different in the D124N Zn-less mutant than in the Zn-less wild type SOD1, suggesting D124N being perhaps not the most adequate model for Zn-less SOD1. Overall, Zn in SOD1 appears to be influencing the Cu site directly by adjusting its reduction potential and geometry. Thus, the role of Zn in SOD1 is not just structural, as was previously thought; it is a vital part of the catalytic machinery. PMID:25083917

  13. Molecular characterization of a cytosolic manganese superoxide dismutase from the Chinese mitten crab, Eriocheir sinensis.

    PubMed

    Zhao, D X; Chen, L Q; Qin, J G; Qin, C J; Zhang, H; Wu, P; Li, E C

    2014-11-11

    A cytosolic manganese superoxide dismutase gene (Es-cMnSOD) was cloned from the Chinese mitten crab Eriocheir sinensis, using reverse transcription-polymerase chain reaction and the rapid amplification of cDNA ends. The open reading frame of Es-cMnSOD is 867 bp in length and encodes a 288-amino acid protein without a signal peptide. The calculated molecular mass of the translated protein of Es-cMnSOD is 31.43 kDa, with an estimated isoelectric point of 6.30. The deduced amino acid sequence of Es-cMnSOD has similarities of 90, 89, 84, 87, and 81% to those of white shrimp Litopenaeus vannamei MnSOD, black tiger shrimp Penaeus monodon MnSOD, giant freshwater prawn Macrobrachium rosenbergii MnSOD, blue crab Callinectes sapidus MnSOD, and red swamp crayfish Procambarus clarkii MnSOD, respectively. Es-cMnSOD contains a manganese superoxide dismutase domain (DVWEHAYY) and 4 conserved amino acids responsible for binding manganese. Es-cMnSOD was expressed in the hemocytes, eyestalk, muscle, intestine, gill, and hepatopancreas. Es-cMnSOD transcripts in hemocytes of E. sinensis increased at 1.5 and 48 h after injection of Aeromonas hydrophila, indicating that the induction of the SOD system response occurred within a short period of time. This study suggests that MnSOD may play a critical role in crab immunity, allowing efficient activation of an early innate immune response in the crab.

  14. Manganese Superoxide Dismutase Regulates a Redox Cycle Within the Cell Cycle

    PubMed Central

    Sarsour, Ehab H.; Kalen, Amanda L.

    2014-01-01

    Abstract Significance: Manganese superoxide dismutase (MnSOD) is a nuclear-encoded and mitochondria-matrix-localized oxidation-reduction (redox) enzyme that regulates cellular redox homeostasis. Cellular redox processes are known to regulate proliferative and quiescent growth states. Therefore, MnSOD and mitochondria-generated reactive oxygen species (ROS) are believed to be critical regulators of quiescent cells' entry into the cell cycle and exit from the proliferative cycle back to the quiescent state. Recent Advances/Critical Issues: Recent evidence suggests that the intracellular redox environment fluctuates during the cell cycle, shifting toward a more oxidized status during mitosis. MnSOD activity is higher in G0/G1 cells compared with S, G2 and M phases. After cell division, MnSOD activity increases in the G1 phase of the daughter generation. The periodic fluctuation in MnSOD activity during the cell cycle inversely correlates with cellular superoxide levels as well as glucose and oxygen consumption. Based on an inverse correlation between MnSOD activity and glucose consumption during the cell cycle, it is proposed that MnSOD is a central molecular player for the “Warburg effect.” Future Directions: In general, loss of MnSOD activity results in aberrant proliferation. A better understanding of the MnSOD and mitochondrial ROS-dependent cell cycle processes may lead to novel approaches to overcome aberrant proliferation. Since ROS have both deleterious (pathological) and beneficial (physiological) effects, it is proposed that “eustress” should be used when discussing ROS processes that regulate normal physiological functions, while “oxidative stress” should be used to discuss the deleterious effects of ROS. Antioxid. Redox Signal. 20, 1618–1627. PMID:23590434

  15. Aggregation propensities of superoxide dismutase G93 hotspot mutants mirror ALS clinical phenotypes.

    PubMed

    Pratt, Ashley J; Shin, David S; Merz, Gregory E; Rambo, Robert P; Lancaster, W Andrew; Dyer, Kevin N; Borbat, Peter P; Poole, Farris L; Adams, Michael W W; Freed, Jack H; Crane, Brian R; Tainer, John A; Getzoff, Elizabeth D

    2014-10-28

    Protein framework alterations in heritable Cu, Zn superoxide dismutase (SOD) mutants cause misassembly and aggregation in cells affected by the motor neuron disease ALS. However, the mechanistic relationship between superoxide dismutase 1 (SOD1) mutations and human disease is controversial, with many hypotheses postulated for the propensity of specific SOD mutants to cause ALS. Here, we experimentally identify distinguishing attributes of ALS mutant SOD proteins that correlate with clinical severity by applying solution biophysical techniques to six ALS mutants at human SOD hotspot glycine 93. A small-angle X-ray scattering (SAXS) assay and other structural methods assessed aggregation propensity by defining the size and shape of fibrillar SOD aggregates after mild biochemical perturbations. Inductively coupled plasma MS quantified metal ion binding stoichiometry, and pulsed dipolar ESR spectroscopy evaluated the Cu(2+) binding site and defined cross-dimer copper-copper distance distributions. Importantly, we find that copper deficiency in these mutants promotes aggregation in a manner strikingly consistent with their clinical severities. G93 mutants seem to properly incorporate metal ions under physiological conditions when assisted by the copper chaperone but release copper under destabilizing conditions more readily than the WT enzyme. Altered intradimer flexibility in ALS mutants may cause differential metal retention and promote distinct aggregation trends observed for mutant proteins in vitro and in ALS patients. Combined biophysical and structural results test and link copper retention to the framework destabilization hypothesis as a unifying general mechanism for both SOD aggregation and ALS disease progression, with implications for disease severity and therapeutic intervention strategies.

  16. Aggregation propensities of superoxide dismutase G93 hotspot mutants mirror ALS clinical phenotypes

    PubMed Central

    Pratt, Ashley J.; Shin, David S.; Merz, Gregory E.; Rambo, Robert P.; Lancaster, W. Andrew; Dyer, Kevin N.; Borbat, Peter P.; Poole, Farris L.; Adams, Michael W. W.; Freed, Jack H.; Crane, Brian R.; Tainer, John A.; Getzoff, Elizabeth D.

    2014-01-01

    Protein framework alterations in heritable Cu, Zn superoxide dismutase (SOD) mutants cause misassembly and aggregation in cells affected by the motor neuron disease ALS. However, the mechanistic relationship between superoxide dismutase 1 (SOD1) mutations and human disease is controversial, with many hypotheses postulated for the propensity of specific SOD mutants to cause ALS. Here, we experimentally identify distinguishing attributes of ALS mutant SOD proteins that correlate with clinical severity by applying solution biophysical techniques to six ALS mutants at human SOD hotspot glycine 93. A small-angle X-ray scattering (SAXS) assay and other structural methods assessed aggregation propensity by defining the size and shape of fibrillar SOD aggregates after mild biochemical perturbations. Inductively coupled plasma MS quantified metal ion binding stoichiometry, and pulsed dipolar ESR spectroscopy evaluated the Cu2+ binding site and defined cross-dimer copper–copper distance distributions. Importantly, we find that copper deficiency in these mutants promotes aggregation in a manner strikingly consistent with their clinical severities. G93 mutants seem to properly incorporate metal ions under physiological conditions when assisted by the copper chaperone but release copper under destabilizing conditions more readily than the WT enzyme. Altered intradimer flexibility in ALS mutants may cause differential metal retention and promote distinct aggregation trends observed for mutant proteins in vitro and in ALS patients. Combined biophysical and structural results test and link copper retention to the framework destabilization hypothesis as a unifying general mechanism for both SOD aggregation and ALS disease progression, with implications for disease severity and therapeutic intervention strategies. PMID:25316790

  17. Molecular cloning and characterization of a cytoplasmic manganese superoxide dismutase and a mitochondrial manganese superoxide dismutase from Chinese mitten crab Eriocheir sinensis.

    PubMed

    Wang, Mengqiang; Wang, Lingling; Yi, Qilin; Gai, Yunchao; Song, Linsheng

    2015-11-01

    Superoxide dismutase (SOD) functions as the first and essential enzyme in the antioxidant system and is ubiquitously existed in both prokaryotes and eukaryotes. In the present study, both cytoplasmic and mitochondrial manganese SOD were identified from Chinese mitten crab Eriocheir sinensis (designed as EscytMnSOD and EsmtMnSOD). The complete nucleotide sequence of EscytMnSOD comprised 1349 bp and consisted of a 5' untranslated regions (UTR) of 43 bp, a 3' UTR of 445 bp and an open reading frame (ORF) of 861 bp encoding a polypeptide of 286 amino acid residues. The full-length cDNA sequence of EsmtMnSOD comprised 990 bp, containing a 5' UTR of 55 bp, a 3' UTR of 278 bp and an ORF of 657 bp encoding a polypeptide of 218 amino acid residues. The deduced amino acid sequences of EscytMnSOD and EsmtMnSOD contained highly conserved MnSOD signature and typical functional domain, and exhibited high similarity with their reported homologues. In the phylogenetic tree, EscytMnSOD and EsmtMnSOD were clustered with their homologues from the land crab Cardisoma armatum. The EscytMnSOD and EsmtMnSOD transcripts were constitutively expressed in haemocytes, muscle, heart, gill, haepatopancreas and gonad, with the highest expression level in gills and haepatopancreas, respectively. The mRNA expression levels of them were all up-regulated in haemocytes with similar profiles after the stimulation of Vibrio anguillarum, Micrococcus luteus and Pichia pastoris. The EsmtMnSOD with low basal expression level responded to invading microbes intensely, while the EscytMnSOD with high basal expression level exhibited mild responses against stimulating microbes. The purified rEscytMnSOD and rEsmtMnSOD proteins exhibited specific Mn(2+)-dependent enzymatic activities, while rEscytMnSOD with lower basic activity displayed higher stability than rEsmtMnSOD. All these results indicated that EscytMnSOD and EsmtMnSOD were efficiently antioxidant enzymes and potentially involved in the innate immune

  18. Replacement of a cytosolic copper/zinc superoxide dismutase by a novel cytosolic manganese superoxide dismutase in crustaceans that use copper (haemocyanin) for oxygen transport.

    PubMed Central

    Brouwer, Marius; Hoexum Brouwer, Thea; Grater, Walter; Brown-Peterson, Nancy

    2003-01-01

    The blue crab, Callinectes sapidus, which uses the copper-dependent protein haemocyanin for oxygen transport, lacks the ubiquitous cytosolic copper-dependent enzyme copper/zinc superoxide dismutase (Cu,ZnSOD) as evidenced by undetectable levels of Cu,ZnSOD activity, protein and mRNA in the hepatopancreas (the site of haemocyanin synthesis) and gills. Instead, the crab has an unusual cytosolic manganese SOD (cytMnSOD), which is retained in the cytosol, because it lacks a mitochondrial transit peptide. A second familiar MnSOD is present in the mitochondria (mtMnSOD). This unique phenomenon occurs in all Crustacea that use haemocyanin for oxygen transport. Molecular phylogeny analysis suggests the MnSOD gene duplication is as old as the origin of the arthropod phylum. cytMnSOD activity in the hepatopancreas changes during the moulting cycle of the crab. Activity is high in intermoult crabs and non-detectable in postmoult papershell crabs. mtMnSOD is present in all stages of the moulting cycle. Despite the lack of cytCu,ZnSOD, crabs have an extracellular Cu,ZnSOD (ecCu,ZnSOD) that is produced by haemocytes, and is part of a large, approx. 160 kDa, covalently-linked protein complex. ecCu,ZnSOD is absent from the hepatopancreas of intermoult crabs, but appears in this tissue at premoult. However, no ecCu,ZnSOD mRNA can be detected, suggesting that the protein is recruited from the haemolymph. Screening of different taxa of the arthropod phylum for Cu,ZnSOD activity shows that those crustaceans that use haemoglobin for oxygen transport have retained cytCu,ZnSOD. It appears, therefore, that the replacement of cytCu,ZnSOD with cytMnSOD is part of an adaptive response to the dynamic, haemocyanin-linked, fluctuations in copper metabolism that occur during the moulting cycle of the crab. PMID:12769817

  19. Crystal Structure of Cu/Zn Superoxide Dismutase from Taenia Solium Reveals Metal-mediated Self-assembly

    SciTech Connect

    A Hernandez-Santoyo; A Landa; E Gonzalez-Mondragon; M Pedraza-Escalona; R Parra-Unda; A Rodriguez-Romero

    2011-12-31

    Taenia solium is the cestode responsible for porcine and human cysticercosis. The ability of this parasite to establish itself in the host is related to its evasion of the immune response and its antioxidant defence system. The latter includes enzymes such as cytosolic Cu/Zn superoxide dismutase. In this article, we describe the crystal structure of a recombinant T. solium Cu/Zn superoxide dismutase, representing the first structure of a protein from this organism. This enzyme shows a different charge distribution at the entrance of the active channel when compared with human Cu/Zn superoxide dismutase, giving it interesting properties that may allow the design of specific inhibitors against this cestode. The overall topology is similar to other superoxide dismutase structures; however, there are several His and Glu residues on the surface of the protein that coordinate metal ions both intra- and intermolecularly. Interestingly, one of these ions, located on the {beta}2 strand, establishes a metal-mediated intermolecular {beta}-{beta} interaction, including a symmetry-related molecule. The factors responsible for the abnormal protein-protein interactions that lead to oligomerization are still unknown; however, high metal levels have been implicated in these phenomena, but exactly how they are involved remains unclear. The present results suggest that this structure could be useful as a model to explain an alternative mechanism of protein aggregation commonly observed in insoluble fibrillar deposits.

  20. β-eudesmol, a sesquiterpene from Teucrium ramosissimum, inhibits superoxide production, proliferation, adhesion and migration of human tumor cell.

    PubMed

    Ben Sghaier, Mohamed; Mousslim, Mohamed; Pagano, Alessandra; Ammari, Youssef; Luis, José; Kovacic, Hervé

    2016-09-01

    Reactive oxygen species are well-known mediators of various biological responses. Recently, new homologues of the catalytic subunit of NADPH oxidase have been discovered in non phagocytic cells. These new homologues (Nox1-Nox5) produce low levels of superoxides compared to the phagocytic homologue Nox2/gp91phox. In this study we examined the effect of β-eudesmol, a sesquiterpenoid alcohol isolated from Teucrium ramosissimum leaves, on proliferation, superoxide anion production, adhesion and migration of human lung (A549) and colon (HT29 and Caco-2) cancer cell lines. Proliferation of tumor cells was inhibited by β-eudesmol. It also significantly inhibited superoxide production in A549 cells. Furthermore, β-eudesmol inhibited adhesion and migration of A549 and HT29 cell. These results demonstrate that β-eudesmol may be a novel anticancer agent for the treatment of lung and colon cancer by different ways: by inhibition of superoxide production or by blocking proliferation, adhesion and migration.

  1. 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.

  2. Effect of xenobiotics on the respiratory activity of rat heart mitochondria and the concomitant formation of superoxide radicals

    SciTech Connect

    Stolze, K.; Nohl, H. . Inst. of Pharmacology and Toxicology)

    1994-03-01

    The effects of the xenobiotics atrazine, benzene, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), lindane, toluene, and xylenol on the respiration of isolated rate heart mitochondria were studied. Bioenergetic parameters such as respiratory control (RC) and ATP/oxygen (P/O) values decreased considerably in the presence of these substances, and a concomitant increase of superoxide radical (O[sub 2][sup [minus

  3. 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

  4. A cytoplasmic Cu-Zn superoxide dismutase SOD1 contributes to hyphal growth and virulence of Fusarium graminearum.

    PubMed

    Yao, Sheng-Hua; Guo, Yan; Wang, Yan-Zhang; Zhang, Dong; Xu, Ling; Tang, Wei-Hua

    2016-06-01

    Superoxide dismutases (SODs) are scavengers of superoxide radicals, one of the main reactive oxygen species (ROS) in the cell. SOD-based ROS scavenging system constitutes the frontline defense against intra- and extracellular ROS, but the roles of SODs in the important cereal pathogen Fusarium graminearum are not very clear. There are five SOD genes in F. graminearum genome, encoding cytoplasmic Cu-Zn SOD1 and MnSOD3, mitochondrial MnSOD2 and FeSOD4, and extracellular CuSOD5. Previous studies reported that the expression of SOD1 increased during infection of wheat coleoptiles and florets. In this work we showed that the recombinant SOD1 protein had the superoxide dismutase activity in vitro, and that the SOD1-mRFP fusion protein localized in the cytoplasm of F. graminearum. The Δsod1 mutants had slightly reduced hyphal growth and markedly increased sensitivity to the intracellular ROS generator menadione. The conidial germination under extracellular oxidative stress was significantly delayed in the mutants. Wheat floret infection assay showed that the Δsod1 mutants had a reduced pathogenicity. Furthermore, the Δsod1 mutants had a significant reduction in production of deoxynivalenol mycotoxin. Our results indicate that the cytoplasmic Cu-Zn SOD1 affects fungal growth probably depending on detoxification of intracellular superoxide radicals, and that SOD1-mediated deoxynivalenol production contributes to the virulence of F. graminearum in wheat head infection. PMID:27037138

  5. Modulation of renal superoxide dismutase by telmisartan therapy in C57BL/6-Ins2Akita diabetic mice

    PubMed Central

    Fujita, Hiroki; Fujishima, Hiromi; Morii, Tsukasa; Sakamoto, Takuya; Komatsu, Koga; Hosoba, Mihoko; Narita, Takuma; Takahashi, Keiko; Takahashi, Takamune; Yamada, Yuichiro

    2012-01-01

    Renal superoxide excess, which is induced by an imbalance of the superoxide-producing enzyme NAD(P)H oxidase and the superoxide-scavenging enzyme superoxide dismutase (SOD) under hyperglycemia, increases oxidative stress and contributes to the development of diabetic nephropathy. In this study, we treated non-obese and hypoinsulinemic C57BL/6-Ins2Akita (C57BL/6-Akita) diabetic mice with telmisartan (5 mg kg−1 per day), an angiotensin II type 1 receptor blocker, or amlodipine (5 mg kg−1 per day), a calcium channel blocker, for 4 weeks and compared the effects of these two anti-hypertensive drugs on renal NAD(P)H oxidase, SOD and transcription factor Nrf2 (NF-E2-related factor 2), which is known to upregulate several antioxidant enzymes including SOD. Vehicle-treated C57BL/6-Akita mice exhibited higher renal NAD(P)H oxidase and lower renal SOD activity with increased levels of renal superoxide than the C57BL/6-wild-type non-diabetic mice. Interestingly, telmisartan treatment not only reduced NAD(P)H oxidase activity but also enhanced SOD activity in C57BL/6-Akita mouse kidneys, leading to a reduction of renal superoxide levels. Furthermore, telmisartan-treated C57BL/6-Akita mice increased the renal protein expression of SOD and Nrf2. In parallel with the reduction of renal superoxide levels, a reduction of urinary albumin levels and a normalization of elevated glomerular filtration rate were observed in telmisartan-treated C57BL/6-Akita mice. In contrast, treatment with amlodipine failed to modulate renal NAD(P)H oxidase, SOD and Nrf2. Finally, treatment of C57BL/6-Akita mice with apocynin, an NAD(P)H oxidase inhibitor, also increased the renal protein expression of SOD and Nrf2. Collectively, our data suggest that NAD(P)H oxidase negatively regulates renal SOD, possibly by downregulation of Nrf2, and that telmisartan could upregulate renal SOD by the suppression of NAD(P)H oxidase and subsequent upregulation of Nrf2, leading to the amelioration of

  6. Parthenolide induces superoxide anion production by stimulating EGF receptor in MDA-MB-231 breast cancer cells.

    PubMed

    D'Anneo, A; Carlisi, D; Emanuele, S; Buttitta, G; Di Fiore, R; Vento, R; Tesoriere, G; Lauricella, M

    2013-12-01

    The sesquiterpene lactone parthenolide (PN) has recently attracted considerable attention because of its anti-microbial, anti-inflammatory and anticancer effects. However, the mechanism of its cytotoxic action on tumor cells remains scarcely defined. We recently provided evidence that the effect exerted by PN in MDA-MB-231 breast cancer cells was mediated by the production of reactive oxygen species (ROS). The present study shows that PN promoted the phosphorylation of EGF receptor (phospho-EGFR) at Tyr1173, an event which was observed already at 1 h of incubation with 25 µM PN and reached a peak at 8-16 h. This effect seemed to be a consequence of ROS production, because N-acetylcysteine (NAC), a powerful ROS scavenger, prevented the increment of phospho-EGFR levels. In addition fluorescence analyses performed using dihydroethidium demonstrated that PN stimulated the production of superoxide anion already at 2-3 h of incubation and the effect further increased prolonging the time of treatment, reaching a peak at 8-16 h. Superoxide anion production was markedly hampered by apocynin, a well known NADPH oxidase (NOX) inhibitor, suggesting that the effect was dependent on NOX activity. The finding that AG1478, an EGFR kinase inhibitor, substantially blocked both EGFR phosphorylation and superoxide anion production strongly suggested that phosphorylation of EGFR can be responsible for the activation of NOX with the consequent production of superoxide anion. Therefore, EGFR phosphorylation can exert a key role in the production of superoxide anion and ROS induced by PN in MDA-MB-231 cells.

  7. 1,1-Diphenyl-2-picrylhydrazyl radical and superoxide anion scavenging activity of Rhizophora mangle (L.) bark

    PubMed Central

    Sánchez, Janet Calero; García, Roberto Faure; Cors, Ma. Teresa Mitjavila

    2010-01-01

    Background: Rhizophora mangle (L.) produce a variety of substances that possesses pharmacological actions. Although it shown antioxidant properties in some assays, there is no available information about its effect on some free radical species. So the objective of the present research is to evaluate the DPPH radical and superoxide anion scavenging properties of R. mangle extract and its polyphenol fraction. Methods: Rhizophora mangle (L.) bark aqueous extract and its major constituent, polyphenols fraction, were investigated for their antioxidant activities employing 2 in vitro assay systems: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radicals scavenging. Results: IC50 for DPPH radical-scavenging activity was 6.7 µg tannins/mL for extract and 7.6 µg tannins/mL for polyphenolic fraction. The extract showed better activity than its fraction (P < 0.05) in the DPPH radicals reducing power. Polyphenolic fraction exhibited better superoxide anion scavenging ability (IC50 = 21.6 µg tannins/mL) than the extract (IC50 = 31.9 µg tannins/mL). Antioxidant activities of both samples increased with the rise of tannins concentration. The comparison of regression lines showed significant differences (P < 0.05) between extract and its polyphenolic fraction in both assays, indicating that extract was more effective in DPPH radical scavenging than its fraction at tannin concentrations below the crossing point of both lines, while that fraction was more effective than extract inhibiting the superoxide anions generation. Conclusions: R. mangle aqueous extract showed a potent antioxidant activity, achieved by the scavenging ability observed against DPPH radicals and superoxide anions. Regarding its polyphenolic composition, the antioxidant effects observed in this study are due, most probably, to the presence of polyphenolic compounds. PMID:21589751

  8. The role of two periplasmic copper- and zinc-cofactored superoxide dismutases in the virulence of Salmonella choleraesuis.

    PubMed

    Sansone, Assunta; Watson, Patricia R; Wallis, Timothy S; Langford, Paul R; Kroll, J Simon

    2002-03-01

    Periplasmic copper- and zinc-cofactored superoxide dismutases ([Cu,Zn]-SODs, SodC) of several Gram-negative pathogens can protect against superoxide-radical-mediated host defences, and thus contribute to virulence. This role has been previously defined for one [Cu,Zn]-SOD in various Salmonella serovars. Following the recent discovery of a second periplasmic [Cu,Zn]-SOD in Salmonella, the effect of knockout mutations in one or both of the original sodC-1 and the new sodC-2 on the virulence of the porcine pathogen Salmonella choleraesuis is investigated here. In comparison to wild-type, while sodC mutants--whether single or double--showed no impairment in growth, they all showed equally enhanced sensitivity to superoxide and a dramatically increased sensitivity to the combination of superoxide and nitric oxide in vitro. This observation had its correlate in experimental infection both ex vivo and in vivo. Mutation of sodC significantly impaired survival of S. choleraesuis in interferon gamma-stimulated murine macrophages compared to wild-type organisms, and all S. choleraesuis sodC mutants persisted in significantly lower numbers than wild-type in BALB/c (Ity(s)) and C3H/HeN (Ity(r)) mice after experimental infection, but in no experimental system were sodC-1 sodC-2 double mutants more attenuated than either single mutant. These data suggest that both [Cu,Zn]-SODs are needed to protect bacterial periplasmic or membrane components. While SodC plays a role in S. choleraesuis virulence, the data presented here suggest that this is through overcoming a threshold effect, probably achieved by acquisition of sodC-1 on a bacteriophage. Loss of either sodC gene confers maximum vulnerability to superoxide on S. choleraesuis.

  9. Detection of superoxide anion and hydrogen peroxide production by cellular NADPH oxidases

    PubMed Central

    Nauseef, William M.

    2013-01-01

    BACKGROUND The recent recognition that isoforms of the cellular NADPH-dependent oxidases, collectively known as the NOX protein family, participate in a wide range of physiologic and pathophysiologic processes in both the animal and plant kingdoms has stimulated interest in the identification, localization, and quantitation of their products in biological settings. Although several tools for reassuring oxidants released extracellularly are available, the specificity and selectivity of the methods for reliable analysis of intracellular oxidants have not matched the enthusiasm for studying NOX proteins. SCOPE OF REVIEW Focusing exclusively on superoxide anion and hydrogen peroxide produced by NOX proteins, this review describes the ideal probe for analysis of O2· and H2O2 generated extracellularly and intracellularly by NOX proteins. An overview of the components, organization, and topology of NOX proteins provides a rationale for applying specific probes for use and a context in which to interpret results and thereby construct plausible models linking NOX-derived oxidants to biological responses. The merits and shortcomings of methods currently in use to assess NOX activity are highlighted, and those assays that provide quantitation of superoxide or H2O2 are contrasted with those intended to examine spatial and temporal aspects of NOX activity. MAJOR CONCLUSIONS Although interest in measuring the extracellular and intracellular products of the NOX protein family is great, robust analytical probes are limited. Several reliable methods for measurement of extracellular O2· and H2O2 by NOX proteins are available. Chemiluminescent probes for both extracellular and intracellular O2· and H2O2 detection have shortcomings that limit their use Options for quantitation of intracellular O2· and H2O2 are very limited However, non-redox sensitive probes and genetically encoded reporters promise to provide spatial and temporal detection of O2· and H2O2 GENERAL SIGNIFICANCE

  10. Nickel superoxide dismutase: structural and functional roles of His1 and its H-bonding network

    DOE PAGES

    Maroney, Michael J.; Cabelli, Diane E.; Ryan, Kelly C.; Guce, Abigail I.; Johnson, Olivia E.; Brunold, Thomas C.; Garman, Scott C.

    2015-01-21

    Crystal structures of nickel-dependent superoxide dismutases (NiSODs) reveal the presence of a H-bonding network formed between the NH group of the apical imidazole ligand from His1 and the Glu17 carboxylate from a neighboring subunit in the hexameric enzyme. This interaction is supported by another intrasubunit H-bond between Glu17 and Arg47. In this study, four mutant NiSOD proteins were produced to experimentally evaluate the roles of this H-bonding network and compare the results with prior predictions from density functional theory calculations. The X-ray crystal structure of H1A-NiSOD, which lacks the apical ligand entirely, reveals that in the absence of the Glu17-His1more » H-bond, the active site is disordered. Characterization of this variant using X-ray absorption spectroscopy (XAS) shows that Ni(II) is bound in the expected N₂S₂ planar coordination site. Despite these structural perturbations, the H1A-NiSOD variant retains 4% of wild-type (WT) NiSOD activity. Three other mutations were designed to preserve the apical imidazole ligand but perturb the H-bonding network: R47A-NiSOD, which lacks the intramolecular H-bonding interaction; E17R/R47A-NiSOD, which retains the intramolecular H-bond but lacks the intermolecular Glu17-His1 H-bond; and E17A/R47ANiSOD, which lacks both H-bonding interactions. These variants were characterized by a combination of techniques, including XAS to probe the nickel site structure, kinetic studies employing pulse-radiolytic production of superoxide, and electron paramagnetic resonance to assess the Ni redox activity. The results indicate that in addition to the roles in redox tuning suggested on the basis of previous computational studies, the Glu17-His1 H-bond plays an important structural role in the proper folding of the “Ni-hook” motif that is a critical feature of the active site.« less

  11. Nickel superoxide dismutase: structural and functional roles of His1 and its H-bonding network

    SciTech Connect

    Maroney, Michael J.; Cabelli, Diane E.; Ryan, Kelly C.; Guce, Abigail I.; Johnson, Olivia E.; Brunold, Thomas C.; Garman, Scott C.

    2015-01-21

    Crystal structures of nickel-dependent superoxide dismutases (NiSODs) reveal the presence of a H-bonding network formed between the NH group of the apical imidazole ligand from His1 and the Glu17 carboxylate from a neighboring subunit in the hexameric enzyme. This interaction is supported by another intrasubunit H-bond between Glu17 and Arg47. In this study, four mutant NiSOD proteins were produced to experimentally evaluate the roles of this H-bonding network and compare the results with prior predictions from density functional theory calculations. The X-ray crystal structure of H1A-NiSOD, which lacks the apical ligand entirely, reveals that in the absence of the Glu17-His1 H-bond, the active site is disordered. Characterization of this variant using X-ray absorption spectroscopy (XAS) shows that Ni(II) is bound in the expected N₂S₂ planar coordination site. Despite these structural perturbations, the H1A-NiSOD variant retains 4% of wild-type (WT) NiSOD activity. Three other mutations were designed to preserve the apical imidazole ligand but perturb the H-bonding network: R47A-NiSOD, which lacks the intramolecular H-bonding interaction; E17R/R47A-NiSOD, which retains the intramolecular H-bond but lacks the intermolecular Glu17-His1 H-bond; and E17A/R47ANiSOD, which lacks both H-bonding interactions. These variants were characterized by a combination of techniques, including XAS to probe the nickel site structure, kinetic studies employing pulse-radiolytic production of superoxide, and electron paramagnetic resonance to assess the Ni redox activity. The results indicate that in addition to the roles in redox tuning suggested on the basis of previous computational studies, the Glu17-His1 H-bond plays an important structural role in the proper folding of the “Ni-hook” motif that is a critical feature of the active site.

  12. Mechanism of the Reaction of Human Manganese Superoxide Dismutase with Peroxynitrite: Nitration of Critical Tyrosine 34.

    PubMed

    Demicheli, Verónica; Moreno, Diego M; Jara, Gabriel E; Lima, Analía; Carballal, Sebastián; Ríos, Natalia; Batthyany, Carlos; Ferrer-Sueta, Gerardo; Quijano, Celia; Estrı́n, Darío A; Martí, Marcelo A; Radi, Rafael

    2016-06-21

    Human Mn-containing superoxide dismutase (hMnSOD) is a mitochondrial enzyme that metabolizes superoxide radical (O2(•-)). O2(•-) reacts at diffusional rates with nitric oxide to yield a potent nitrating species, peroxynitrite anion (ONOO(-)). MnSOD is nitrated and inactivated in vivo, with active site Tyr34 as the key oxidatively modified residue. We previously reported a k of ∼1.0 × 10(5) M(-1) s(-1) for the reaction of hMnSOD with ONOO(-) by direct stopped-flow spectroscopy and the critical role of Mn in the nitration process. In this study, we further established the mechanism of the reaction of hMnSOD with ONOO(-), including the necessary re-examination of the second-order rate constant by an independent method and the delineation of the microscopic steps that lead to the regio-specific nitration of Tyr34. The redetermination of k was performed by competition kinetics utilizing coumarin boronic acid, which reacts with ONOO(-) at a rate of ∼1 × 10(6) M(-1) s(-1) to yield the fluorescence product, 7-hydroxycoumarin. Time-resolved fluorescence studies in the presence of increasing concentrations of hMnSOD provided a k of ∼1.0 × 10(5) M(-1) s(-1), fully consistent with the direct method. Proteomic analysis indicated that ONOO(-), but not other nitrating agents, mediates the selective modification of active site Tyr34. Hybrid quantum-classical (quantum mechanics/molecular mechanics) simulations supported a series of steps that involve the initial reaction of ONOO(-) with Mn(III) to yield Mn(IV) and intermediates that ultimately culminate in 3-nitroTyr34. The data reported herein provide a kinetic and mechanistic basis for rationalizing how MnSOD constitutes an intramitochondrial target for ONOO(-) and the microscopic events, with atomic level resolution, that lead to selective and efficient nitration of critical Tyr34. PMID:27227512

  13. Nickel superoxide dismutase: structural and functional roles of His1 and its H-bonding network.

    PubMed

    Ryan, Kelly C; Guce, Abigail I; Johnson, Olivia E; Brunold, Thomas C; Cabelli, Diane E; Garman, Scott C; Maroney, Michael J

    2015-02-01

    Crystal structures of nickel-dependent superoxide dismutases (NiSODs) reveal the presence of a H-bonding network formed between the NH group of the apical imidazole ligand from His1 and the Glu17 carboxylate from a neighboring subunit in the hexameric enzyme. This interaction is supported by another intrasubunit H-bond between Glu17 and Arg47. In this study, four mutant NiSOD proteins were produced to experimentally evaluate the roles of this H-bonding network and compare the results with prior predictions from density functional theory calculations. The X-ray crystal structure of H1A-NiSOD, which lacks the apical ligand entirely, reveals that in the absence of the Glu17-His1 H-bond, the active site is disordered. Characterization of this variant using X-ray absorption spectroscopy (XAS) shows that Ni(II) is bound in the expected N2S2 planar coordination site. Despite these structural perturbations, the H1A-NiSOD variant retains 4% of wild-type (WT) NiSOD activity. Three other mutations were designed to preserve the apical imidazole ligand but perturb the H-bonding network: R47A-NiSOD, which lacks the intramolecular H-bonding interaction; E17R/R47A-NiSOD, which retains the intramolecular H-bond but lacks the intermolecular Glu17-His1 H-bond; and E17A/R47A-NiSOD, which lacks both H-bonding interactions. These variants were characterized by a combination of techniques, including XAS to probe the nickel site structure, kinetic studies employing pulse-radiolytic production of superoxide, and electron paramagnetic resonance to assess the Ni redox activity. The results indicate that in addition to the roles in redox tuning suggested on the basis of previous computational studies, the Glu17-His1 H-bond plays an important structural role in the proper folding of the "Ni-hook" motif that is a critical feature of the active site. PMID:25580509

  14. Nickel superoxide dismutase: structural and functional roles of His1 and its H-bonding network.

    PubMed

    Ryan, Kelly C; Guce, Abigail I; Johnson, Olivia E; Brunold, Thomas C; Cabelli, Diane E; Garman, Scott C; Maroney, Michael J

    2015-02-01

    Crystal structures of nickel-dependent superoxide dismutases (NiSODs) reveal the presence of a H-bonding network formed between the NH group of the apical imidazole ligand from His1 and the Glu17 carboxylate from a neighboring subunit in the hexameric enzyme. This interaction is supported by another intrasubunit H-bond between Glu17 and Arg47. In this study, four mutant NiSOD proteins were produced to experimentally evaluate the roles of this H-bonding network and compare the results with prior predictions from density functional theory calculations. The X-ray crystal structure of H1A-NiSOD, which lacks the apical ligand entirely, reveals that in the absence of the Glu17-His1 H-bond, the active site is disordered. Characterization of this variant using X-ray absorption spectroscopy (XAS) shows that Ni(II) is bound in the expected N2S2 planar coordination site. Despite these structural perturbations, the H1A-NiSOD variant retains 4% of wild-type (WT) NiSOD activity. Three other mutations were designed to preserve the apical imidazole ligand but perturb the H-bonding network: R47A-NiSOD, which lacks the intramolecular H-bonding interaction; E17R/R47A-NiSOD, which retains the intramolecular H-bond but lacks the intermolecular Glu17-His1 H-bond; and E17A/R47A-NiSOD, which lacks both H-bonding interactions. These variants were characterized by a combination of techniques, including XAS to probe the nickel site structure, kinetic studies employing pulse-radiolytic production of superoxide, and electron paramagnetic resonance to assess the Ni redox activity. The results indicate that in addition to the roles in redox tuning suggested on the basis of previous computational studies, the Glu17-His1 H-bond plays an important structural role in the proper folding of the "Ni-hook" motif that is a critical feature of the active site.

  15. Impact of Superoxide Dismutase Mimetic AEOL 10150 on the Endothelin System of Fischer 344 Rats

    PubMed Central

    Ganesh, Devi; Kumarathasan, Prem; Thomson, Errol M.; St-Germain, Carly; Blais, Erica; Crapo, James; Vincent, Renaud

    2016-01-01

    Endothelin-1 is a potent vasoconstrictor and mitogenic peptide involved in the regulation of vasomotor tone and maintenance of blood pressure. Oxidative stress activates the endothelin system, and is implicated in pulmonary and cardiovascular diseases including hypertension, congestive heart failure, and atherosclerosis. Superoxide dismutase mimetics designed with the aim of treating diseases that involve reactive oxygen species in their pathophysiology may exert a hypotensive effect, but effects on the endothelin system are unknown. Our objective was to determine the effect of the superoxide dismutase mimetic AEOL 10150 on the basal endothelin system in vivo. Male Fischer-344 rats were injected subcutaneously with 0, 2 or 5 mg/kg body weight of AEOL 10150 in saline. Plasma oxidative stress markers and endothelins (bigET-1, ET-1, ET-2, ET-3) as well as lung and heart endothelin/nitric oxide system gene expressions were measured using HPLC-Coularray, HPLC-Fluorescence and RT-PCR respectively. AEOL 10150 reduced (p<0.05) the circulating levels of isoprostane (-25%) and 3-nitrotyrosine (-50%) measured in plasma 2h and 24h after treatment, confirming delivery of a physiologically-relevant dose and the potent antioxidant activity of the drug. The reduction in markers of oxidative stress coincided with sustained 24h decrease (p<0.05) of plasma levels of ET-1 (-50%) and ET-3 (-10%). Expression of preproET-1 and endothelin converting enzyme-1 mRNA were not altered significantly in the lungs. However preproET-1 (not significant) and ECE-1 mRNA (p<0.05) were increased (10–25%) in the heart. Changes in the lungs included decrease (p<0.05) of mRNA for the ET-1 clearance receptor ETB and the vasoconstriction-signaling ETA receptor (-30%), and an early surge of inducible nitric oxide synthase expression followed by sustained decrease (-40% after 24 hours). The results indicate that interception of the endogenous physiological flux of reactive nitrogen species and reactive

  16. Real-time monitoring of superoxide accumulation and antioxidant activity in a brain slice model using an electrochemical cytochrome c biosensor.

    PubMed

    Ganesana, Mallikarjunarao; Erlichman, Joseph S; Andreescu, Silvana

    2012-12-15

    The overproduction of reactive oxygen species and the resulting damage are central to the pathology of many diseases. The study of the temporal and spatial accumulation of reactive oxygen species has been limited because of the lack of specific probes and techniques capable of continuous measurement. We demonstrate the use of a miniaturized electrochemical cytochrome c (Cyt c) biosensor for real-time measurements and quantitative assessment of superoxide production and inactivation by natural and engineered antioxidants in acutely prepared brain slices from mice. Under control conditions, superoxide radicals produced from the hippocampal region of the brain in 400-μm-thick sections were well within the range of detection of the electrode. Exposure of the slices to ischemic conditions increased the superoxide production twofold and measurements from the slices were stable over a 3- to 4-h period. The stilbene derivative and anion channel inhibitor 4,4'-diisothiocyano-2,2'-disulfonic stilbene markedly reduced the extracellular superoxide signal under control conditions, suggesting that a transmembrane flux of superoxide into the extracellular space may occur as part of normal redox signaling. The specificity of the electrode for superoxide released by cells in the hippocampus was verified by the exogenous addition of superoxide dismutase (SOD), which decreased the superoxide signal in a dose-dependent manner. Similar results were seen with the addition of the SOD mimetic cerium oxide nanoparticles (nanoceria), in that the superoxide anion radical scavenging activity of nanoceria with an average diameter of 15 nm was equivalent to 527 U of SOD for each 1 μg/ml of nanoceria added. This study demonstrates the potential of electrochemical biosensors for studying real-time dynamics of reactive oxygen species in a biological model and the utility of these measurements in defining the relative contribution of superoxide to oxidative injury. PMID:23085519

  17. Real-time monitoring of superoxide accumulation and antioxidant activity in a brain slice model using an electrochemical cytochrome c biosensor

    PubMed Central

    Ganesana, Mallikarjunarao; Erlichman, Joseph S.; Andreescu, Silvana

    2012-01-01

    The overproduction of reactive oxygen species and resulting damage are central to the pathology of many diseases. The study of the temporal and spatial accumulation of reactive oxygen species has been limited due to the lack of specific probes and techniques capable of continuous measurement. We demonstrate the use of a miniaturized electrochemical cytochrome C (Cyt C) biosensor for real-time measurements and quantitative assessment of superoxide production and inactivation by natural and engineered antioxidants in acutely prepared brain slices from mice. During control conditions, superoxide radicals produced from the hippocampal region of the brain in 400 μm thick sections were well within the range of detection of the electrode. Exposure of the slices to ischemic conditions increased the superoxide production two fold and measurements from the slices were stable over a 3–4 hour period. The stilbene derivative and anion channel inhibitor, 4,4′-diisothiocyano-2,2′-disulfonic stilbene (DIDS), markedly reduced the extracellular superoxide signal under control conditions suggesting that a transmembrane flux of superoxide into the extracellular space may occur as part of normal redox signaling. The specificity of the electrode for superoxide released by cells in the hippocampus was verified by the exogenous addition of superoxide dismutase (SOD) which decreased the superoxide signal in a dose-dependent manner. Similar results were seen with the addition of the SOD-mimetic, cerium oxide nanoparticles (nanoceria) where the superoxide anion radical scavenging activity of nanoceria with an average diameter of 15 nm was equivalent to 527 U of SOD for each 1 μg/ml of nanoceria added. This study demonstrates the potential of electrochemical biosensors for studying real-time dynamics of reactive oxygen species in a biological model and the utility of these measurements in defining the relative contribution of superoxide to oxidative injury. PMID:23085519

  18. Release of gelatinase and superoxide from human mononuclear phagocytes in response to particulate Tamm Horsfall protein.

    PubMed Central

    Thomas, D. B.; Davies, M.; Williams, J. D.

    1993-01-01

    This study describes the in vitro activation of human mononuclear phagocytes by particulate Tamm Horsfall protein (THP). Peripheral blood monocytes phagocytosed THP particles with the accompanying release of superoxide radicals, N-acetyl-beta-D-glucosaminidase, and neutral metalloproteinase. Immunoprecipitation and substrate gel analysis identified the neutral proteinase as a 95-kd gelatinase. A comparison with other particulate ligands highlighted the specificity of the response to THP and showed that the magnitude of the response was comparable with that obtained with lipopolysaccharide (100 micrograms/ml). Parallel studies using peritoneal macrophages resulted in a similar pattern of enzyme release and reactive oxygen species synthesis. THP has been implicated in the pathogenesis of tubulointerstitial nephritis associated with reflux nephropathy. The present study indicates that an inflammatory response initiated by a neutrophil-THP interaction may be extended into a chronic phase via the activation of mononuclear phagocytes. The subsequent release of reactive oxygen metabolites and proteinases may contribute to the tissue damage and fibrosis associated with chronic immune-mediated tubulointerstitial nephritis. Images Figure 4 Figure 5 Figure 6 PMID:8380953

  19. Voltage-Induced Misfolding of Zinc-Replete ALS Mutant Superoxide Dismutase-1.

    PubMed

    Shi, Yunhua; Acerson, Mark J; Shuford, Kevin L; Shaw, Bryan F

    2015-10-21

    The monomerization of Cu, Zn superoxide dismutase (SOD1) is an early step along pathways of misfolding linked to amyotrophic lateral sclerosis (ALS). Monomerization requires the reversal of two post-translational modifications that are thermodynamically favorable: (i) dissociation of active-site metal ions and (ii) reduction of intramolecular disulfide bonds. This study found, using amide hydrogen/deuterium (H/D) exchange, capillary electrophoresis, and lysine-acetyl protein charge ladders, that ALS-linked A4V SOD1 rapidly monomerizes and partially unfolds in an external electric field (of physiological strength), without loss of metal ions, exposure to disulfide-reducing agents, or Joule heating. Voltage-induced monomerization was not observed for metal-free A4V SOD1, metal-free WT SOD1, or metal-loaded WT SOD1. Computational modeling suggested a mechanism for this counterintuitive effect: subunit macrodipoles of dimeric SOD1 are antiparallel and amplified 2-fold by metal coordination, which increases torque at the dimer interface as subunits rotate to align with the electric field. PMID:26207449

  20. Genome-Wide Characterization and Expression Profiles of the Superoxide Dismutase Gene Family in Gossypium.

    PubMed

    Zhang, Jingbo; Li, Bo; Yang, Yang; Hu, Wenran; Chen, Fangyuan; Xie, Lixia; Fan, Ling

    2016-01-01

    Superoxide dismutase (SOD) as a group of significant and ubiquitous enzymes plays a critical function in plant growth and development. Previously this gene family has been investigated in Arabidopsis and rice; it has not yet been characterized in cotton. In our study, it was the first time for us to perform a genome-wide analysis of SOD gene family in cotton. Our results showed that 10 genes of SOD gene family were identified in Gossypium arboreum and Gossypium raimondii, including 6 Cu-Zn-SODs, 2 Fe-SODs, and 2 Mn-SODs. The chromosomal distribution analysis revealed that SOD genes are distributed across 7 chromosomes in Gossypium arboreum and 8 chromosomes in Gossypium raimondii. Segmental duplication is predominant duplication event and major contributor for expansion of SOD gene family. Gene structure and protein structure analysis showed that SOD genes have conserved exon/intron arrangement and motif composition. Microarray-based expression analysis revealed that SOD genes have important function in abiotic stress. Moreover, the tissue-specific expression profile reveals the functional divergence of SOD genes in different organs development of cotton. Taken together, this study has imparted new insights into the putative functions of SOD gene family in cotton. Findings of the present investigation could help in understanding the role of SOD gene family in various aspects of the life cycle of cotton. PMID:27660755

  1. Inhalation of Talc Induces Infiltration of Macrophages and Upregulation of Manganese Superoxide Dismutase in Rats.

    PubMed

    Shim, Ilseob; Kim, Hyun-Mi; Yang, Sangyoung; Choi, Min; Seo, Gyun-Baek; Lee, Byung-Woo; Yoon, Byung-Il; Kim, Pilje; Choi, Kyunghee

    2015-01-01

    Talc is a mineral that is widely used in cosmetic products, antiseptics, paints, and rubber manufacturing. Although the toxicological effects of talc have been studied extensively, until now no detailed inhalation study of talc focusing on oxidative stress has been done. This repeated 4 weeks whole-body inhalation toxicity study of talc involved Sprague-Dawley rats. Male and female groups of rats were exposed to inhaled talc at 0, 5, 50, and 100 mg/m(3) for 6 hours daily, 5 days/week for 4 weeks. The objective was to identify the 4-week inhalation toxicity of talc and investigate antioxidant activity after exposure to talc. There were no treatment-related symptoms or mortality in rats treated with talc. Glucose (GLU) was decreased significantly in male rats exposed to 50 and 100 mg/m(3) of talc. Histopathological examination revealed infiltration of macrophages on the alveolar walls and spaces near the terminal and respiratory bronchioles. In male and female rats exposed to 100 mg/m(3) talc, expression of superoxide dismutase 2, a typical biological indicator of oxidative damage, was significantly increased. Thus, inhalation of talc induces macrophage aggregations and oxidative damage in the lung.

  2. Molecular characterization of two CuZn-superoxide dismutases in a sea anemone.

    PubMed

    Plantivaux, Amandine; Furla, Paola; Zoccola, Didier; Garello, Ginette; Forcioli, Didier; Richier, Sophie; Merle, Pierre-Laurent; Tambutté, Eric; Tambutté, Sylvie; Allemand, Denis

    2004-10-15

    Cnidarians living in symbiosis with photosynthetic cells--called zooxanthellae--are submitted to high oxygen levels generated by photosynthesis. To cope with this hyperoxic state, symbiotic cnidarians present a high diversity of superoxide dismutases (SOD) isoforms. To understand better the mechanism of resistance of cnidarian hosts to hyperoxia, we studied copper- and zinc-containing SOD (CuZnSOD) from Anemonia viridis, a temperate symbiotic sea anemone. We cloned two CuZnSOD genes that we call AvCuZnSODa and AvCuZnSODb. Their molecular analysis suggests that the AvCuZnSODa transcript encodes an extracellular form of CuZnSOD, whereas the AvCuZnSODb transcript encodes an intracellular form. Using in situ hybridization, we showed that both AvCuZnSODa and AvCuZnSODb transcripts are expressed in the endodermal and ectodermal cells of the sea anemone, but not in the zooxanthellae. The genomic flanking sequences of AvCuZnSODa and AvCuZnSODb revealed different putative binding sites for transcription factors, suggesting different modes of regulation for the two genes. This study represents a first step in the understanding of the molecular mechanisms of host animal resistance to permanent hyperoxia status resulting from the photosynthetic symbiosis. Moreover, AvCuZnSODa and AvCuZnSODb are the first SODs cloned from a diploblastic animal, contributing to the evolutionary understanding of SODs. PMID:15451057

  3. A Cu/Zn superoxide dismutase from Jatropha curcas enhances salt tolerance of Arabidopsis thaliana.

    PubMed

    Liu, Z B; Zhang, W J; Gong, X D; Zhang, Q; Zhou, L R

    2015-01-01

    Superoxide dismutases (SODs) are involved in protecting plants against diverse biotic and abiotic stresses. In the present study, a novel Cu/Zn-SOD gene (JcCu/Zn-SOD) was cloned from Jatropha curcas L. Quantitative reverse transcription-polymerase chain reaction analysis revealed that JcCu/Zn-SOD is constitutively expressed in different tissues of J. curcas and induced under NaCl treatment. To characterize the function of this gene with respect to salt tolerance, the construct p35S:JcCu/Zn-SOD was developed and transformed into Arabidopsis using Agrobacterium-mediated transformation. Compared with wild-type, transgenic plants over-expressing JcCu/Zn-SOD showed enhanced tolerance to salt stress during germination, seedling establishment, and growth in terms of longer root, larger rosette area, and a larger number of leaves in addition to higher SOD activity levels under NaCl stress. In addition, over-expression of JcCu/Zn-SOD resulted in lower monodialdehyde content in transgenic Arabidopsis compared to wild-type plants under the same NaCl stress. Therefore, JcCu/Zn-SOD can increase a plant salt stress tolerance potentially by reducing oxidant injury. PMID:25867355

  4. Differential inhibition of Arabidopsis superoxide dismutases by peroxynitrite-mediated tyrosine nitration

    PubMed Central

    Holzmeister, Christian; Gaupels, Frank; Geerlof, Arie; Sarioglu, Hakan; Sattler, Michael; Durner, Jörg; Lindermayr, Christian

    2015-01-01

    Despite the importance of superoxide dismutases (SODs) in the plant antioxidant defence system little is known about their regulation by post-translational modifications. Here, we investigated the in vitro effects of nitric oxide derivatives on the seven SOD isoforms of Arabidopsis thaliana. S-nitrosoglutathione, which causes S-nitrosylation of cysteine residues, did not influence SOD activities. By contrast, peroxynitrite inhibited the mitochondrial manganese SOD1 (MSD1), peroxisomal copper/zinc SOD3 (CSD3), and chloroplastic iron SOD3 (FSD3), but no other SODs. MSD1 was inhibited by up to 90% but CSD3 and FSD3 only by a maximum of 30%. Down-regulation of these SOD isoforms correlated with tyrosine (Tyr) nitration and both could be prevented by the peroxynitrite scavenger urate. Site-directed mutagenesis revealed that—amongst the 10 Tyr residues present in MSD1—Tyr63 was the main target responsible for nitration and inactivation of the enzyme. Tyr63 is located nearby the active centre at a distance of only 5.26 Å indicating that nitration could affect accessibility of the substrate binding pocket. The corresponding Tyr34 of human manganese SOD is also nitrated, suggesting that this might be an evolutionarily conserved mechanism for regulation of manganese SODs. PMID:25428993

  5. Brain beta-amyloid accumulation in transgenic mice expressing mutant superoxide dismutase 1.

    PubMed

    Turner, Bradley J; Li, Qiao-Xin; Laughton, Katrina M; Masters, Colin L; Lopes, Elizabeth C; Atkin, Julie D; Cheema, Surindar S

    2004-12-01

    Oxidative stress is implicated in both the deposition and pathogenesis of beta-amyloid (Abeta) protein in Alzheimer's disease (AD). Accordingly, overexpression of the antioxidant enzyme superoxide dismutase 1 (SOD1) in neuronal cells and transgenic AD mice reduces Abeta toxicity and accumulation. In contrast, mutations in SOD1 associated with amyotrophic lateral sclerosis (ALS) confer enhanced pro-oxidative enzyme activities. We therefore examined whether ALS-linked mutant SOD1 overexpression in motor neuronal cells or transgenic ALS mice modulates Abeta toxicity or its accumulation in the brain. Aggregated, but not freshly solubilised, substrate-bound Abeta peptides induced degenerative morphology and cytotoxicity in motor neuron-like NSC-34 cells. Transfection of NSC-34 cells with human wild-type SOD1 attenuated Abeta-induced toxicity, however this neuroprotective effect was also observed for ALS-linked mutant SOD1. Analysis of the cerebral cortex, brainstem, cerebellum and olfactory bulb from transgenic SOD1G93A mice using enzyme-linked immunosorbent assay of acid-guanidine extracts revealed age-dependent elevations in Abeta levels, although not significantly different from wild-type mouse brain. In addition, brain amyloid protein precursor (APP) levels remained unaltered as a consequence of mutant SOD1 expression. We therefore conclude that mutant SOD1 overexpression promotes neither Abeta toxicity nor brain accumulation in these ALS models.

  6. Synthesis, crystal structure, superoxide scavenging activity, anticancer and docking studies of novel adamantyl nitroxide derivatives

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-he; Sun, Jin; Wang, Shan; Bu, Wei; Yao, Min-na; Gao, Kai; Song, Ying; Zhao, Jin-yi; Lu, Cheng-tao; Zhang, En-hu; Yang, Zhi-fu; Wen, Ai-dong

    2016-03-01

    A novel adamantyl nitroxide derivatives has been synthesized and characterized by IR, ESI-MS and elemental analysis. Quantum chemical calculations have also been performed to calculate the molecular geometry using density functional theory (B3LYP) with the 6-31G (d,p) basis set. The calculated results showed that the optimized geometry can well reproduce the crystal structure. The antioxidant and antiproliferative activity were evaluated by superoxide (NBT) and MTT assay. The adamantyl nitroxide derivatives exhibited stronger scavenging ability towards O2· - radicals when compared to Vitamin C, and demonstrated a remarked anticancer activity against all the tested cell lines, especially Bel-7404 cells with IC50 of 43.3 μM, compared to the positive control Sorafenib (IC50 = 92.0 μM). The results of molecular docking within EGFR using AutoDock confirmed that the titled compound favorably fitted into the ATP binding site of EGFR and would be a potential anticancer agent.

  7. Fructose protects baker's yeast against peroxide stress: potential role of catalase and superoxide dismutase.

    PubMed

    Semchyshyn, Halyna M; Lozinska, Liudmyla M

    2012-11-01

    The negative effects of fructose due to its chronic consumption are well documented, while short-term application of fructose is found to protect different types of cells against oxidative stress. Reactive oxygen species (ROS) are suggested to mediate both the cytotoxic and defensive effects. Here, we compare the influence of glucose and fructose on yeast under H(2)O(2)-induced stress. Under control conditions, fructose-grown comparing with glucose-grown yeast demonstrated higher metabolic activity and ROS level. Therefore, fructose was suggested to provoke a mild stress that resulted in the acquisition of cellular resistance to lethal challenges, which explained the higher survival of fructose-grown yeast under H(2)O(2)-induced shock. Exposure to H(2)O(2) increased ROS level in glucose-grown cells, whereas it decreased the ROS level in fructose-grown cells. Hydrogen peroxide activated superoxide dismutase (SOD) and catalase in both the cell types studied, but glucose-grown cells demonstrated a sharp rise of the activities, while cells grown on fructose showed a broad peak of activation. Thus, fructose is likely to protect the antioxidant enzymes against their inactivation by H(2)O(2). Despite a different type of the enzyme activation in both the studied cell types (glucose- and fructose-grown), a strong positive correlation between SOD and catalase was found. The physiological meaning of this relationship and possible mechanisms of the fructose protective effect are discussed.

  8. Salicylic acid-induced superoxide generation catalyzed by plant peroxidase in hydrogen peroxide-independent manner.

    PubMed

    Kimura, Makoto; Kawano, Tomonori

    2015-01-01

    It has been reported that salicylic acid (SA) induces both immediate spike and long lasting phases of oxidative burst represented by the generation of reactive oxygen species (ROS) such as superoxide anion radical (O2(•-)). In general, in the earlier phase of oxidative burst, apoplastic peroxidase are likely involved and in the late phase of the oxidative burst, NADPH oxidase is likely involved. Key signaling events connecting the 2 phases of oxidative burst are calcium channel activation and protein phosphorylation events. To date, the known earliest signaling event in response to exogenously added SA is the cell wall peroxidase-catalyzed generation of O2(•-) in a hydrogen peroxide (H2O2)-dependent manner. However, this model is incomplete since the source of the initially required H2O2 could not be explained. Based on the recently proposed role for H2O2-independent mechanism for ROS production catalyzed by plant peroxidases (Kimura et al., 2014, Frontiers in Plant Science), we hereby propose a novel model for plant peroxidase-catalyzed oxidative burst fueled by SA.

  9. A superoxide dismutase/catalase mimetic nanomedicine for targeted therapy of inflammatory bowel disease.

    PubMed

    Zhang, Qixiong; Tao, Hui; Lin, Yongyao; Hu, Ying; An, Huijie; Zhang, Dinglin; Feng, Shibin; Hu, Houyuan; Wang, Ruibing; Li, Xiaohui; Zhang, Jianxiang

    2016-10-01

    Oxidative stress, resulting from excessive generation of reactive oxygen species (ROS), plays a pivotal role in the initiation and progression of inflammatory bowel disease (IBD). To develop an efficacious and safe nanotherapy against IBD, we designed and developed a superoxide dismutase/catalase mimetic nanomedicine comprising a hydrogen peroxide-eliminating nanomatrix and a free radical scavenger Tempol (Tpl). To this end, an oxidation-responsive β-cyclodextrin material (OxbCD) was synthesized, and a Tpl-loaded OxbCD nanoparticle (Tpl/OxbCD NP) was produced. Hydrolysis of OxbCD NP could be triggered by hydrogen peroxide, leading to on-demand release of loaded Tpl molecules from Tpl/OxbCD NP. OxbCD NP was able to efficiently accumulate in the inflamed colon in mice, thereby dramatically reducing nonspecific distribution after oral delivery. In three mouse colitis models, oral administration of Tpl/OxbCD NP notably mitigated manifestations relevant to colitis, and significantly suppressed expression of proinflammatory mediators, with the efficacy superior over free Tpl or a control nanomedicine based on poly(lactide-co-glycolide) (PLGA). Accordingly, by scavenging multiple components of ROS, Tpl/OxbCD NP may effectively reduce ulcerative colitis in mice, and it can be intensively developed as a translational nanomedicine for the management of IBD and other inflammatory diseases. PMID:27525680

  10. Lipid-associated aggregate formation of superoxide dismutase-1 is initiated by membrane-targeting loops.

    PubMed

    Chng, Choon-Peng; Strange, Richard W

    2014-11-01

    Copper-Zinc superoxide dismutase 1 (SOD1) is a homodimeric enzyme that protects cells from oxidative damage. Hereditary and sporadic amyotrophic lateral sclerosis may be linked to SOD1 when the enzyme is destabilized through mutation or environmental stress. The cytotoxicity of demetallated or apo-SOD1 aggregates may be due to their ability to cause defects within cell membranes by co-aggregating with phospholipids. SOD1 monomers may associate with the inner cell membrane to receive copper ions from membrane-bound copper chaperones. But how apo-SOD1 interacts with lipids is unclear. We have used atomistic molecular dynamics simulations to reveal that flexible electrostatic and zinc-binding loops in apo-SOD1 dimers play a critical role in the binding of 1-octanol clusters and phospholipid bilayer, without any significant unfolding of the protein. The apo-SOD1 monomer also associates with phospholipid bilayer via its zinc-binding loop rather than its exposed hydrophobic dimerization interface. Our observed orientation of the monomer on the bilayer would facilitate its association with a membrane-bound copper chaperone. The orientation also suggests how membrane-bound monomers could act as seeds for membrane-associated SOD1 aggregation. PMID:25212695

  11. Immature copper-zinc superoxide dismutase and familial amyotrophic lateral sclerosis.

    PubMed

    Seetharaman, Sai V; Prudencio, Mercedes; Karch, Celeste; Holloway, Stephen P; Borchelt, David R; Hart, P John

    2009-10-01

    Mutations in human copper-zinc superoxide dismutase (SOD1) cause an inherited form of amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease, motor neuron disease). Insoluble forms of mutant SOD1 accumulate in neural tissues of human ALS patients and in spinal cords of transgenic mice expressing these polypeptides, suggesting that SOD1-linked ALS is a protein misfolding disorder. Understanding the molecular basis for how the pathogenic mutations give rise to SOD1 folding intermediates, which may themselves be toxic, is therefore of keen interest. A critical step on the SOD1 folding pathway occurs when the copper chaperone for SOD1 (CCS) modifies the nascent SOD1 polypeptide by inserting the catalytic copper cofactor and oxidizing its intrasubunit disulfide bond. Recent studies reveal that pathogenic SOD1 proteins coming from cultured cells and from the spinal cords of transgenic mice tend to be metal-deficient and/or lacking the disulfide bond, raising the possibility that the disease-causing mutations may enhance levels of SOD1-folding intermediates by preventing or hindering CCS-mediated SOD1 maturation. This mini-review explores this hypothesis by highlighting the structural and biophysical properties of the pathogenic SOD1 mutants in the context of what is currently known about CCS structure and action. Other hypotheses as to the nature of toxicity inherent in pathogenic SOD1 proteins are not covered. PMID:19596823

  12. Homology modeling and comparative profiling of superoxide dismutase among extremophiles: exiguobacterium as a model organism.

    PubMed

    Pathak, Rajiv; Narang, Pankaj; Chandra, Muktesh; Kumar, Raj; Sharma, P K; Gautam, Hemant K

    2014-12-01

    Superoxide dismutase (SOD), a well known antioxidant enzyme, is known to exert its presence across bacteria to humans. Apart from their well-known antioxidant defense mechanisms, their association with various extremophiles in response to various stress conditions is poorly understood. Here, we have discussed the conservation and the prevalence of SODs among 21 representative extremophiles. A systematic investigation of aligned amino acid sequences of SOD from all the selected extremophiles revealed a consensus motif D-[VLE]-[FW]-E-H-[AS]-Y-[YM]. To computationally predict the correlation of SOD with the various stress conditions encountered by these extremophiles, Exiguobacterium was selected as a model organism which is known to survive under various adverse extremophilic conditions. Interestingly, our phylogenetic study based on SOD homology revealed that Exiguobacterium sibiricum was one of the closest neighbors of Deinococcus radiodurans and Thermus thermophilus. Next, we sought to predict 3-D model structure of SOD for E. sibiricum (PMDB ID: 0078260), which showed >95 % similarity with D. radiodurans R1 SOD. The reliability of the predicted SOD model was checked by using various validation metrics, including Ramachandran plot, Z-score and normalized qualitative model energy analysis score. Further, various physicochemical properties of E. sibiricum SOD were calculated using different prominent resources.

  13. Purification of Helicobacter pylori superoxide dismutase and cloning and sequencing of the gene.

    PubMed Central

    Spiegelhalder, C; Gerstenecker, B; Kersten, A; Schiltz, E; Kist, M

    1993-01-01

    The superoxide dismutase (SOD) of Helicobacter pylori, a pathogenic bacterium which colonizes the gastric mucosa, evoking a marked inflammatory response, was purified and characterized, and the N-terminal amino acid sequence was determined. The enzyme consists of two identical subunits each with an apparent molecular weight of 24,000. Analysis of the primary structure and inhibition studies revealed that H. pylori possesses a typical procaryotic iron-containing enzyme. No other isoenzymes could be detected. Indirect gold immunostaining of H. pylori SOD with a polyclonal antibody directed against the iron-containing SOD of Escherichia coli showed a surface-associated localization of the enzyme. The H. pylori SOD gene was cloned by functional complementation of a SOD-deficient E. coli mutant. Sequencing and alignment revealed striking homology to the following facultative intracellular human pathogens: Listeria ivanovii, Listeria monocytogenes, Coxiella burnetti, Porphyromonas gingivalis, Legionella pneumophila, and Entamoeba histolytica. An open reading frame of 642 bp encoding 214 amino acids was determined. There was no leader sequence detectable. Cloning of the H. pylori SOD gene is one of the prerequisites to investigation of its pathophysiological role in the defense against antimicrobial mechanisms of polymorphonuclear granulocytes. Images PMID:8225605

  14. Hindlimb Motor Neurons Require Cu/Zn Superoxide Dismutase for Maintenance of Neuromuscular Junctions

    PubMed Central

    Flood, Dorothy G.; Reaume, Andrew G.; Gruner, John A.; Hoffman, Eric K.; Hirsch, James D.; Lin, Yin-Guo; Dorfman, Karen S.; Scott, Richard W.

    1999-01-01

    The role of oxidative damage in neurodegenerative disease was investigated in mice lacking cytoplasmic Cu/Zn superoxide dismutase (SOD), created by deletion of the SOD1 gene (SOD1−/−). SOD1−/− mice developed a chronic peripheral hindlimb axonopathy. Mild denervation of muscle was detected at 2 months, and behavioral and physiological motor deficits were present at 5–7 months of age. Ventral root axons were shrunken but were normal in number. The somatosensory system in SOD1−/− mice was mildly affected. SOD1−/− mice expressing Cu/Zn SOD only in brain and spinal cord were generated using transgenic mice expressing mouse SOD1 driven by the neuron-specific synapsin promoter. Neuron-specific expression of Cu/Zn SOD in SOD1−/− mice rescued motor neurons from the neuropathy. Therefore, Cu/Zn SOD is not required for normal motor neuron survival, but is necessary for the maintenance of normal neuromuscular junctions by hindlimb motor neurons. PMID:10433959

  15. Superoxide Dismutase: A Predicting Factor for Boar Semen Characteristics for Short-Term Preservation

    PubMed Central

    Nemec Svete, Alenka

    2014-01-01

    Superoxide dismutase (SOD), total antioxidant capacity (TAC), and thiobarbituric acid reactive substances (TBARS) in seminal plasma were evaluated on the basis of receiver operating characteristics (ROC) analysis as predictors for distinguishing satisfactory from unsatisfactory boar semen samples after storage. SOD on day 0 correlated significantly with progressive motility (r = −0.686; P < 0.05) and viability (r = −0.513; P < 0.05) after storage; TBARS correlated only with motility (r = −0.480; P < 0.05). Semen samples that, after 3 days of storage, fulfilled all criteria for semen characteristics (viability > 85%, motility > 70%, progressive motility > 25%, and normal morphology > 50%) had significantly lower SOD levels on the day 0 than those with at least one criterion not fulfilled (P < 0.05) following storage. SOD levels of less than 1.05 U/mL predicted with 87.5% accuracy that fresh semen will suit the requirements for satisfactory semen characteristics after storage, while semen with SOD levels higher than 1.05 U/mL will not fulfill with 100% accuracy at least one semen characteristic after storage. These results support the proposal that SOD in fresh boar semen can be used as a predictor of semen quality after storage. PMID:24729963

  16. Exendin-4 promotes extracellular-superoxide dismutase expression in A549 cells through DNA demethylation

    PubMed Central

    Yasuda, Hiroyuki; Mizukami, Koji; Hayashi, Mutsuna; Kamiya, Tetsuro; Hara, Hirokazu; Adachi, Tetsuo

    2016-01-01

    Exendin-4 is an agonist of the glucagon-like peptide 1 receptor (GLP-1R) and is used in the treatment of type 2 diabetes. Since human GLP-1R has been identified in various cells besides pancreatic cells, exendin-4 is expected to exert extrapancreatic actions. It has also been suggested to affect gene expression through epigenetic regulation, such as DNA methylation and/or histone modifications. Furthermore, the expression of extracellular-superoxide dismutase (EC-SOD), a major SOD isozyme that is crucially involved in redox homeostasis, is regulated by epigenetic factors. In the present study, we demonstrated that exendin-4 induced the demethylation of DNA in A549 cells, which, in turn, affected the expression of EC-SOD. Our results showed that the treatment with exendin-4 up-regulated the expression of EC-SOD through GLP-1R and demethylated some methyl-CpG sites (methylated cytosine at 5'-CG-3') in the EC-SOD gene. Moreover, the treatment with exendin-4 inactivated DNA methyltransferases (DNMTs), but did not change their expression levels. In conclusion, the results of the present study demonstrated for the first time that exendin-4 regulated the expression of EC-SOD by reducing the activity of DNMTs and demethylation of DNA within the EC-SOD promoter region in A549 cells. PMID:26798195

  17. Role of cortisol and superoxide dismutase in psychological stress induced anovulation.

    PubMed

    Kala, Manika; Nivsarkar, Manish

    2016-01-01

    Stress has been identified as a potential trigger for reproductive dysfunctions, but the psycho-physiological pathway behind the effect of stress on ovulation remains unexplored. The present research work highlights the plausible mechanism of psychological stress on ovulation in mice by targeting superoxide dismutase (SOD), an enzyme involved in ovulation. For this, three consecutive studies were carried out. The first study aimed to determine the effect of psychological stress induced change in cortisol level, behavioral parameters and normal estrous cyclicity. The effect on mRNA expression of SOD subtypes, follicular growth in histological sections of ovaries and the difference in oocyte quality and number, upon superovulation were assessed in the subsequent studies. The results indicate that psychological stress model causes an increase in cortisol level (p⩽0.05) with development of anhedonia, depression and anxiety. An irregular estrous cycle was observed in stressed mice with an upregulation in mRNA expression of SOD subtypes. Histological sections revealed an increase in atretic antral follicle with an impaired follicular development. Moreover, immature oocytes were obtained from superovulated stressed mice. The study concludes that psychological stress results in anovulation which may be due to increase in cortisol level and SOD activity in stressed mice.

  18. Impacts of nitric oxide and superoxide on renal medullary oxygen transport and urine concentration.

    PubMed

    Fry, Brendan C; Edwards, Aurélie; Layton, Anita T

    2015-05-01

    The goal of this study was to investigate the reciprocal interactions among oxygen (O2), nitric oxide (NO), and superoxide (O2 (-)) and their effects on medullary oxygenation and urinary output. To accomplish that goal, we developed a detailed mathematical model of solute transport in the renal medulla of the rat kidney. The model represents the radial organization of the renal tubules and vessels, which centers around the vascular bundles in the outer medulla and around clusters of collecting ducts in the inner medulla. Model simulations yield significant radial gradients in interstitial fluid oxygen tension (Po2) and NO and O2 (-) concentration in the OM and upper IM. In the deep inner medulla, interstitial fluid concentrations become much more homogeneous, as the radial organization of tubules and vessels is not distinguishable. The model further predicts that due to the nonlinear interactions among O2, NO, and O2 (-), the effects of NO and O2 (-) on sodium transport, osmolality, and medullary oxygenation cannot be gleaned by considering each solute's effect in isolation. An additional simulation suggests that a sufficiently large reduction in tubular transport efficiency may be the key contributing factor, more so than oxidative stress alone, to hypertension-induced medullary hypoxia. Moreover, model predictions suggest that urine Po2 could serve as a biomarker for medullary hypoxia and a predictor of the risk for hospital-acquired acute kidney injury.

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

    PubMed

    Zhu, Jia-Ying; Ze, Sang-Zi; Stanley, David W; Yang, Bin

    2014-09-01

    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. The cDNAs for ecCuZnSOD, icCuZnSOD, and MnSOD, respectively, encode 24.55, 15.81, and 23.14 kDa polypeptides, which possess structural features typical of other insect SODs. They showed 20-94% identity to other known SOD sequences from Bombyx mori, Musca domestica, Nasonia vitripennis, Pediculus humanus corporis, and Tribolium castaneum. Expression of these genes was analyzed in selected tissues and developmental stages, and following exposure to Escherichia coli and parasitization by Scleroderma guani. We recorded expression of all three SODs in cuticle, fat body, and hemocytes and in the major developmental stages. Relatively higher expressions were detected in late-instar larvae and pupae, compared to other developmental stages. Transcriptional levels were upregulated following bacterial infection. Analysis of pupae parasitized by S. guani revealed that expression of T. molitor SOD genes was significantly induced following parasitization. We infer that these genes act in immune response and in host-parasitoid interactions. PMID:25042129

  20. [Role of free radicals on canine bile-induced pancreatitis and effect of superoxide dismutase].

    PubMed

    Sato, T

    1995-06-01

    The purpose of this study was to determine the effect of superoxide dismutase (SOD) on canine experimental pancreatitis. Pancreatitis was induced by retrograde biliary juice injection (0.5 ml/kg) to accessory pancreatic duct. Twenty-one mongrel dogs were divided into two groups, i.e. control (untreated) group (n = 13) and SOD-treated group (n = 8). In SOD-treated group, SOD 5000 units/kg was administered from celiac artery immediately after onset of pancreatitis. Xanthine oxidase (XOD), malondialdehyde (MDA), phospholipase (PL), and SOD were assayed from pancreatic tissue 1 and 3 hours after onset of pancreatitis. Serum amylase, elastase I, calcium, and WBC were assayed for 7 days after onset of pancreatitis. XOD and MDA levels were increased in untreated group, and not significantly changed in treated group with statistical difference. PL levels were increased after onset of pancreatitis in both groups and SOD levels were not changed even in treated group. No statistical difference was seen in PL and SOD levels between two groups. Increase of XOD levels suggests continuous generating of free radical species from pancreatic tissue, and SOD inhibits this increase. Increase of PL level was not improved by SOD. Serum laboratory findings and survival rates were not improved by SOD treatment.

  1. The structure of the Caenorhabditis elegans manganese superoxide dismutase MnSOD-3-azide complex

    DOE PAGES

    Hunter, Gary J.; Trinh, Chi H.; Bonetta, Rosalin; Stewart, Emma E.; Cabelli, Diane E.; Hunter, Therese

    2015-08-27

    C. elegans MnSOD-3 has been implicated in the longevity pathway and its mechanism of catalysis is relevant to the aging process and carcinogenesis. The structures of MnSOD-3 provide unique crystallographic evidence of a dynamic region of the tetrameric interface (residues 41–54). We have determined the structure of the MnSOD-3-azide complex to 1.77-Å resolution. The analysis of this complex shows that the substrate analog, azide, binds end-on to the manganese center as a sixth ligand and that it ligates directly to a third and new solvent molecule also positioned within interacting distance to the His30 and Tyr34 residues of the substratemore » access funnel. This is the first structure of a eukaryotic MnSOD-azide complex that demonstrates the extended, uninterrupted hydrogen-bonded network that forms a proton relay incorporating three outer sphere solvent molecules, the substrate analog, the gateway residues, Gln142, and the solvent ligand. This configuration supports the formation and release of the hydrogen peroxide product in agreement with the 5-6-5 catalytic mechanism for MnSOD. The high product dissociation constant k₄ of MnSOD-3 reflects low product inhibition making this enzyme efficient even at high levels of superoxide.« less

  2. Trace element and magnesium levels and superoxide dismutase activity in rheumatoid arthritis.

    PubMed

    Tuncer, S; Kamanli, A; Akçil, E; Kavas, G O; Seçkin, B; Atay, M B

    1999-05-01

    It has been suggested that reactive oxygen metabolites and trace elements play some role in the etiology and pathogenesis of rheumatoid arthritis (RA). Superoxide dismutase (SOD) is believed to exert an important protective role against oxygen toxicity. The aim of the study was to investigate the probable changes in the levels of trace elements and SOD activity in RA. Plasma and erythrocyte copper, zinc, and magnesium levels and erythrocyte SOD activity were measured in groups of controls and RA cases. Significantly increased erythrocyte SOD activity was found in RA patients in comparison with controls (p < 0.0001). A rise in erythrocyte Zn level (p < 0.0001) and plasma Cu level (p < 0.0001) and a decrease in erythrocyte Cu level (p < 0.05) and plasma Zn level (p < 0.05) were obtained in RA patients when compared to controls. Plasma and erythrocyte Mg levels of the RA patients showed slight and statistically insignificant reductions when compared to controls (p > 0.05). In RA patients, there were positive correlations between erythrocyte SOD activity and Mg level (r = 0.4345, p < 0.01) and between erythrocyte Zn level and plasma Cu level (r = 0.4132, p < 0.01). There were negative correlations between erythrocyte SOD activity and plasma Zn level (r = -0.3605, p < 0.05) and between plasma Zn level and erythrocyte Cu level (r = -0.4578, p < 0.01) in RA patients.

  3. Superoxide radical production in response to environmental hypoxia in cultured shrimp.

    PubMed

    Zenteno-Savín, Tania; Saldierna, Ricardo; Ahuejote-Sandoval, Mauricio

    2006-01-01

    Markers of oxidative stress in response to hypoxia and reoxygenation were assessed in Pacific white shrimp (Litopenaeus vannamei). Adult shrimp were either exposed to hypoxia (1 mg O(2)/L) for 6, 12, or 24 h followed by 1-h reoxygenation, or exposed to hypoxia for 24 h followed by 1- to 6-h reoxygenation. In all cases, shrimp maintained at constant normoxia were used as controls. Spectrophotometric techniques were applied to analyze lactate concentration, superoxide radical (O(2)(*-)) production, lipid peroxidation (TBARS), and antioxidant capacity status in muscle, hepatopancreas, and gill samples. Results indicate differences among tissues, even under control conditions. O(2)(*-) production and TBARS levels were higher in hepatopancreas than in gill or muscle. No effect of exposure to hypoxia was found. However, reoxygenation following exposure to hypoxia was found to affect the oxidative metabolism of muscle and hepatopancreas from cultured shrimp. Lactate concentration and O(2)(*-) production increased while antioxidant capacity decreased in hepatopancreas and muscle in the first hours of reoxygenation. This could translate into tissue damage, which may significantly jeopardize the commercial aquaculture product.

  4. Superoxide mediated production of hydroxyl radicals by magnetite nanoparticles: demonstration in the degradation of 2-chlorobiphenyl.

    PubMed

    Fang, Guo-Dong; Zhou, Dong-Mei; Dionysiou, Dionysios D

    2013-04-15

    Increasing attention has been paid to magnetite nanoparticles (MNPs) due to their highly reductive reactivity toward environmental contaminants. However, there is little information related to the generation of reactive oxygen species (ROS) by MNPs, which in fact plays a vital role for the transformation of contaminants. In this paper, the degradation of 2-chlorobiphenyl (2-CB) by MNPs was investigated. The role of ROS generated by MNPs in this process was elucidated. The results demonstrated that hydroxyl radicals (OH) generated by MNPs at low pH could efficiently degrade 2-CB. The mechanism of the formation of OH by MNPs was divided into two steps: (i) the superoxide radical anion (O2(-)) mediated production of hydrogen peroxide (H2O2), and (ii) the reaction of formed H2O2 with Fe(II) dissolved from MNPs to produce OH through Fenton reaction. Comparison of the degradation products of 2-CB by MNPs with MNPs/ethanol and Fenton reagents further supported the involvement of OH in the degradation of 2-CB. The degradation efficiency of 2-CB by MNPs under acidic conditions was higher than that in alkaline solution. These findings provide a new insight into the understanding of reactivity of MNPs for the transformation of 2-CB and possibly other relevant environmental contaminants. PMID:23434481

  5. The role of two superoxide dismutase mRNAs in rye aluminium tolerance.

    PubMed

    Sánchez-Parra, B; Figueiras, A M; Abd El-Moneim, D; Contreras, R; Rouco, R; Gallego, F J; Benito, C

    2015-05-01

    Aluminium (Al) is the main factor that limits crop production in acidic soils. There is evidence that antioxidant enzymes such as superoxide dismutase (SOD) play a key role against Al-induced oxidative stress in several plant species. Rye is one of the most Al-tolerant cereals and exudes both citrate and malate from the roots in response to Al. The role of SOD against Al-induced oxidative stress has not been studied in rye. Al accumulation, lipid peroxidation, H₂O₂ production and cell death were significantly higher in sensitive than in tolerant rye cultivars. Also, we characterised two genes for rye SOD: ScCu/ZnSOD and ScMnSOD. These genes were located on the chromosome arms of 2RS and 3RL, respectively, and their corresponding hypothetical proteins were putatively classified as cytosolic and mitochondrial, respectively. The phylogenetic relationships indicate that the two rye genes are orthologous to the corresponding genes of other Poaceae species. In addition, we studied Al-induced changes in the expression profiles of mRNAs from ScCu/ZnSOD and ScMnSOD in the roots and leaves of tolerant Petkus and sensitive Riodeva rye. These genes are mainly expressed in roots in both ryes, their repression being induced by Al. The tolerant cultivar has more of both mRNAs than the sensitive line, indicating that they are probably involved in Al tolerance.

  6. Effects of temperature stress on expression of fimbriae and superoxide dismutase by Porphyromonas gingivalis.

    PubMed Central

    Amano, A; Sharma, A; Sojar, H T; Kuramitsu, H K; Genco, R J

    1994-01-01

    We examined the biosynthesis of fimbriae and superoxide dismutase (SOD) produced by the periodontopathic bacterium Porphyromonas gingivalis in response to elevated temperature. P. gingivalis 2561, grown at 37 degrees C to mid-logarithmic phase, was subsequently incubated at 39, 41, and 43 degrees C, respectively, to stationary phase. There was no difference in the growth of cells at 37 and 39 degrees C. However, at 39 degrees C there was a 54% reduction in the amount of fimbrillin (fimbriae) as well as decreased expression of mRNA for fimA. On the other hand, under the same conditions, a more than twofold increase in the amount of SOD activity, as well as in the levels of SOD mRNA, was observed. Moreover, cells cultured for 20 h at 39 degrees C showed an 86% decrease of fimbrillin protein and a threefold increase in SOD activity. These observations suggest that P. gingivalis may undergo alterations in its virulence and susceptibility to host immune responses as a result of the elevated temperatures found in inflamed periodontal pockets. Images PMID:7927742

  7. Modification and inactivation of Cu,Zn-superoxide dismutase by the lipid peroxidation product, acrolein

    PubMed Central

    Kang, Jung Hoon

    2013-01-01

    Acrolein is the most reactive aldehydic product of lipid peroxidation and is found to be elevated in the brain when oxidative stress is high. The effects of acrolein on the structure and function of human Cu,Zn-superoxide dismutase (SOD) were examined. When Cu,Zn-SOD was incubated with acrolein, the covalent crosslinking of the protein was increased, and the loss of enzymatic activity was increased in a dose-dependent manner. Reactive oxygen species (ROS) scavengers and copper chelators inhibited the acrolein-mediated Cu,Zn-SOD modification and the formation of carbonyl compound. The present study shows that ROS may play a critical role in acrolein-induced Cu,Zn-SOD modification and inactivation. When Cu,Zn-SOD that has been exposed to acrolein was subsequently analyzed by amino acid analysis, serine, histidine, arginine, threonine and lysine residues were particularly sensitive. It is suggested that the modification and inactivation of Cu,Zn-SOD by acrolein could be produced by more oxidative cell environments. [BMB Reports 2013; 46(11): 555-560] PMID:24152914

  8. Superoxide dismutase--mentor of abiotic stress tolerance in crop plants.

    PubMed

    Gill, Sarvajeet Singh; Anjum, Naser A; Gill, Ritu; Yadav, Sandeep; Hasanuzzaman, Mirza; Fujita, Masayuki; Mishra, Panchanand; Sabat, Surendra C; Tuteja, Narendra

    2015-07-01

    Abiotic stresses impact growth, development, and productivity, and significantly limit the global agricultural productivity mainly by impairing cellular physiology/biochemistry via elevating reactive oxygen species (ROS) generation. If not metabolized, ROS (such as O2 (•-), OH(•), H2O2, or (1)O2) exceeds the status of antioxidants and cause damage to DNA, proteins, lipids, and other macromolecules, and finally cellular metabolism arrest. Plants are endowed with a family of enzymes called superoxide dismutases (SODs) that protects cells against potential consequences caused by cytotoxic O2 (•-) by catalyzing its conversion to O2 and H2O2. Hence, SODs constitute the first line of defense against abiotic stress-accrued enhanced ROS and its reaction products. In the light of recent reports, the present effort: (a) overviews abiotic stresses, ROS, and their metabolism; (b) introduces and discusses SODs and their types, significance, and appraises abiotic stress-mediated modulation in plants; (c) analyzes major reports available on genetic engineering of SODs in plants; and finally, (d) highlights major aspects so far least studied in the current context. Literature appraised herein reflects clear information paucity in context with the molecular/genetic insights into the major functions (and underlying mechanisms) performed by SODs, and also with the regulation of SODs by post-translational modifications. If the previous aspects are considered in the future works, the outcome can be significant in sustainably improving plant abiotic stress tolerance and efficiently managing agricultural challenges under changing climatic conditions.

  9. The effect of UV-B radiation on Bufo arenarum embryos survival and superoxide dismutase activity.

    PubMed

    Herkovits, J; D'Eramo, J L; Fridman, O

    2006-03-01

    The exposure of Bufo arenarum embryos to 300-310 nm UV-B at a dose of 4,104 Joule/m(2) resulted in 100% lethality within 24 hr while 820 Joule/m(2) was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m(2) at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 +/- 14.29, 74.5 +/- 13.19, 39.5 +/- 6.99 and 10.7 +/- 1.89 respectively while for control embryos it was 10.88 +/- 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure. PMID:16823076

  10. Extracellular superoxide production, viability and redox poise in response to desiccation in recalcitrant Castanea sativa seeds.

    PubMed

    Roach, Thomas; Beckett, Richard P; Minibayeva, Farida V; Colville, Louise; Whitaker, Claire; Chen, Hongying; Bailly, Christophe; Kranner, Ilse

    2010-01-01

    Reactive oxygen species (ROS) are implicated in seed death following dehydration in desiccation-intolerant 'recalcitrant' seeds. However, it is unknown if and how ROS are produced in the apoplast and if they play a role in stress signalling during desiccation. We studied intracellular damage and extracellular superoxide (O(2)(.-)) production upon desiccation in Castanea sativa seeds, mechanisms of O(2)(.-) production and the effect of exogenously supplied ROS. A transient increase in extracellular O(2)(.-) production by the embryonic axes preceded significant desiccation-induced viability loss. Thereafter, progressively more oxidizing intracellular conditions, as indicated by a significant shift in glutathione half-cell reduction potential, accompanied cell and axis death, coinciding with the disruption of nuclear membranes. Most hydrogen peroxide (H(2)O(2))-dependent O(2)(.-) production was found in a cell wall fraction that contained extracellular peroxidases (ECPOX) with molecular masses of approximately 50 kDa. Cinnamic acid was identified as a potential reductant required for ECPOX-mediated O(2)(.-) production. H(2)O(2), applied exogenously to mimic the transient ROS burst at the onset of desiccation, counteracted viability loss of sub-lethally desiccation-stressed seeds and of excised embryonic axes grown in tissue culture. Hence, extracellular ROS produced by embryonic axes appear to be important signalling components involved in wound response, regeneration and growth.

  11. Superoxide dismutase 2 gene and cancer risk: evidence from an updated meta-analysis

    PubMed Central

    Kang, Sang Wook

    2015-01-01

    Superoxide dismutase, one of the antioxidant enzymes, plays an important role in defense against reactive oxygen species. Many previous studies reported the association between SOD2 polymorphism and the cancer risk but the results were divergent. Therefore, we performed a meta-analysis to investigate the association between SOD2 polymorphism and the cancer susceptibility. We searched in Electronic database including Pubmed, Embase, google of scholar, and Korean Studies Information Service System (KISS) for this meta-analysis. Odds ratio (OR), 95 confidence interval (CI), and p value were calculated to evaluate the relation between SOD2 polymorphism and risk of cancer using Comprehensive Meta-analysis software (Corporation, NJ, USA). The fifty-two studies including 26,865 cancer cases and 32,464 control subjects were analyzed for meta-analysis. Our meta-analysis revealed that SOD2 polymorphism statistically increased or decreased the susceptibility of cancer. In the present study, we could find that SOD2 polymorphism was related to the development of non-Hodgkin lymphoma, lung cancer, and colorectal cancer. It suggested that SOD2 polymorphism might be a candidate marker of cancer. PMID:26628947

  12. Manganese superoxide dismutase is required to maintain osteoclast differentiation and function under static force

    PubMed Central

    Guo, Tao; Zhang, Liqiang; Konermann, Anna; Zhou, Hong; Jin, Fang; Liu, Wenjia

    2015-01-01

    Bone homeostasis is maintained by the balance of osteoblasts (OBs) and osteoclasts (OCs). Increased activity of OCs not only contributes to pathological bone resorption, such as osteoporosis and periodontitis, but also is responsible for physiological conditions like orthodontic tooth movement (OTM). However, the detailed mechanism by which orthodontic force promotes the formation of OCs is still poorly understood. In this study, we confirmed that static force promoted the differentiation of human cord monocytes (HMNCs) into OCs depending on loading time and magnitude. Protein expression profiles among HMNCs, HMNCs subjected to static force and mature OCs were established via 2-DE and MALDI-TOF-MS analyses. Total respective protein spot numbers of 549 ± 13, 612 ± 19 and 634 ± 16 were detected in each of the gels by image analysis. The five proteins identified were plasminogen activator inhibitor 2 (PAI-2, Spot 1), peroxiredoxin-6 (PRD-6, Spot 3), manganese superoxide dismutase (SOD2, Spot 6), Rho GDP-dissociation inhibitor 2 (Rho-GDI2, Spot 11) and L-lactate dehydrogenase B chain (L-LDH, Spot 15). More importantly, we revealed that SOD2 was required to maintain monocyte differentiation into functional OCs and may become a potential target for regulating the efficiency of OTM in the future. PMID:25619900

  13. Cellular distribution of copper to superoxide dismutase involves scaffolding by membranes

    PubMed Central

    Pope, Christopher R.; De Feo, Christopher J.; Unger, Vinzenz M.

    2013-01-01

    Efficient delivery of copper ions to specific intracellular targets requires copper chaperones that acquire metal cargo through unknown mechanisms. Here we demonstrate that the human and yeast copper chaperones (CCS) for superoxide dismutase 1 (SOD1), long thought to exclusively reside in the cytosol and mitochondrial intermembrane space, can engage negatively charged bilayers through a positively charged lipid-binding interface. The significance of this membrane-binding interface is established through SOD1 activity and genetic complementation studies in Saccharomyces cerevisiae, showing that recruitment of CCS to the membrane is required for activation of SOD1. Moreover, we show that a CCS:SOD1 complex binds to bilayers in vitro and that CCS can interact with human high affinity copper transporter 1. Shifting current paradigms, we propose that CCS-dependent copper acquisition and distribution largely occur at membrane interfaces and that this emerging role of the bilayer may reflect a general mechanistic aspect of cellular transition metal ion acquisition. PMID:24297923

  14. Are superoxide dismutase 2 and nitric oxide synthase polymorphisms associated with idiopathic infertility?

    PubMed

    Faure, Celine; Leveille, Pauline; Dupont, Charlotte; Julia, Chantal; Chavatte-Palmer, Pascale; Sutton, Angela; Levy, Rachel

    2014-08-01

    The aim of this study was to investigate in a case-control study the associations between idiopathic infertility and antioxidant gene polymorphisms. One hundred ten infertile subjects (58 women and 52 men) with a history of idiopathic infertility and 69 fertile subjects (35 women and 34 men) with no history of infertility were included by three hospital departments of reproductive biology in the NCT01093378 French government clinical trial. Genotyping was assessed by real-time polymerase chain reaction with TaqMan assay. We examined genetic polymorphisms affecting five antioxidant enzymes: manganese superoxide dismutase (MnSOD), myeloperoxidase (MPO), glutathione peroxidase 1 (GPx1), catalase (CAT), and endothelial nitric oxide synthase (eNOS). The presence of at least 1 Ala-MnSOD allele (rs4880) increased significantly the risk of infertility (odds ratio [OR] 2.94; 95% confidence interval [CI], 1.14, 7.60; p=0.03) in male subjects. Moreover, the presence of 2 G-eNOS allele (rs1799983) increased significantly the risk of infertility in both men and women (OR 1.91; 95% CI, 1.04, 3.54; p=0.04). Our observations lead to the hypothesis that the genetic susceptibility modulating oxidative stress may represent a risk factor for male idiopathic infertility.

  15. Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model

    PubMed Central

    Achour, Imène; Arel-Dubeau, Anne-Marie; Renaud, Justine; Legrand, Manon; Attard, Everaldo; Germain, Marc; Martinoli, Maria-Grazia

    2016-01-01

    Parkinson’s disease (PD) is a progressive neurodegenerative disorder, primarily affecting dopaminergic neurons in the substantia nigra. There is currently no cure for PD and present medications aim to alleviate clinical symptoms, thus prevention remains the ideal strategy to reduce the prevalence of this disease. The goal of this study was to investigate whether oleuropein (OLE), the major phenolic compound in olive derivatives, may prevent neuronal degeneration in a cellular dopaminergic model of PD, differentiated PC12 cells exposed to the potent parkinsonian toxin 6-hydroxydopamine (6-OHDA). We also investigated OLE’s ability to mitigate mitochondrial oxidative stress and modulate the autophagic flux. Our results obtained by measuring cytotoxicity and apoptotic events demonstrate that OLE significantly decreases neuronal death. OLE could also reduce mitochondrial production of reactive oxygen species resulting from blocking superoxide dismutase activity. Moreover, quantification of autophagic and acidic vesicles in the cytoplasm alongside expression of specific autophagic markers uncovered a regulatory role for OLE against autophagic flux impairment induced by bafilomycin A1. Altogether, our results define OLE as a neuroprotective, anti-oxidative and autophagy-regulating molecule, in a neuronal dopaminergic cellular model. PMID:27517912

  16. Trichloroethylene exposure aggravates behavioral abnormalities in mice that are deficient in superoxide dismutase.

    PubMed

    Otsuki, Noriyuki; Homma, Takujiro; Fujiwara, Hiroki; Kaneko, Kenya; Hozumi, Yasukazu; Shichiri, Mototada; Takashima, Mizuki; Ito, Junitsu; Konno, Tasuku; Kurahashi, Toshihiro; Yoshida, Yasukazu; Goto, Kaoru; Fujii, Satoshi; Fujii, Junichi

    2016-08-01

    Trichloroethylene (TCE) has been implicated as a causative agent for Parkinson's disease (PD). The administration of TCE to rodents induces neurotoxicity associated with dopaminergic neuron death, and evidence suggests that oxidative stress as a major player in the progression of PD. Here we report on TCE-induced behavioral abnormality in mice that are deficient in superoxide dismutase 1 (SOD1). Wild-type (WT) and SOD1-deficient (Sod1(-/-)) mice were intraperitoneally administered TCE (500 mg/kg) over a period of 4 weeks. Although the TCE-administrated Sod1(-/-) mice showed marked abnormal motor behavior, no significant differences were observed among the experimental groups by biochemical and histopathological analyses. However, treating mouse neuroblastoma-derived NB2a cells with TCE resulted in the down regulation of the SOD1 protein and elevated oxidative stress under conditions where SOD1 production was suppressed. Taken together, these data indicate that SOD1 plays a pivotal role in protecting motor neuron function against TCE toxicity. PMID:27166294

  17. Superoxide Dismutase 1 Protects Hepatocytes from Type I Interferon-Driven Oxidative Damage

    PubMed Central

    Bhattacharya, Anannya; Hegazy, Ahmed N.; Deigendesch, Nikolaus; Kosack, Lindsay; Cupovic, Jovana; Kandasamy, Richard K.; Hildebrandt, Andrea; Merkler, Doron; Kühl, Anja A.; Vilagos, Bojan; Schliehe, Christopher; Panse, Isabel; Khamina, Kseniya; Baazim, Hatoon; Arnold, Isabelle; Flatz, Lukas; Xu, Haifeng C.; Lang, Philipp A.; Aderem, Alan; Takaoka, Akinori; Superti-Furga, Giulio; Colinge, Jacques; Ludewig, Burkhard; Löhning, Max; Bergthaler, Andreas

    2015-01-01

    Summary Tissue damage caused by viral hepatitis is a major cause of morbidity and mortality worldwide. Using a mouse model of viral hepatitis, we identified virus-induced early transcriptional changes in the redox pathways in the liver, including downregulation of superoxide dismutase 1 (Sod1). Sod1−/− mice exhibited increased inflammation and aggravated liver damage upon viral infection, which was independent of T and NK cells and could be ameliorated by antioxidant treatment. Type I interferon (IFN-I) led to a downregulation of Sod1 and caused oxidative liver damage in Sod1−/− and wild-type mice. Genetic and pharmacological ablation of the IFN-I signaling pathway protected against virus-induced liver damage. These results delineate IFN-I mediated oxidative stress as a key mediator of virus-induced liver damage and describe a mechanism of innate-immunity-driven pathology, linking IFN-I signaling with antioxidant host defense and infection-associated tissue damage. Video Abstract PMID:26588782

  18. Molecular Interaction Mechanism between 2-Mercaptobenzimidazole and Copper-Zinc Superoxide Dismutase

    PubMed Central

    Teng, Yue; Zou, Luyi; Huang, Ming; Chen, Yadong

    2014-01-01

    2-Mercaptobenzimidazole (MBI) is widely utilized as a corrosion inhibitor, copper-plating brightener and rubber accelerator. The residue of MBI in the environment is potentially harmful. In the present work, the toxic interaction of MBI with the important antioxidant enzyme copper-zinc superoxide dismutase (Cu/ZnSOD) was investigated using spectroscopic and molecular docking methods. MBI can interact with Cu/ZnSOD to form an MBI-Cu/ZnSOD complex. The binding constant, number of binding sites and thermodynamic parameters were measured, which indicated that MBI could spontaneously bind with Cu/ZnSOD with one binding site through hydrogen bonds and van der Waals forces. MBI bound into the Cu/ZnSOD interface of two subdomains, which caused some microenvironmental and secondary structure changes of Cu/ZnSOD and further resulted in the inhibition of Cu/ZnSOD activity. This work provides direct evidence at a molecular level to show that exposure to MBI could induce changes in the structure and function of the enzyme Cu/ZnSOD. The estimated methods in this work may be applied to probe molecular interactions of biomacromolecules and other pollutants and drugs. PMID:25157630

  19. Modification and inactivation of Cu,Zn-superoxide dismutase by the lipid peroxidation product, acrolein.

    PubMed

    Kang, Jung Hoon

    2013-11-01

    Acrolein is the most reactive aldehydic product of lipid peroxidation and is found to be elevated in the brain when oxidative stress is high. The effects of acrolein on the structure and function of human Cu,Zn-superoxide dismutase (SOD) were examined. When Cu,Zn-SOD was incubated with acrolein, the covalent crosslinking of the protein was increased, and the loss of enzymatic activity was increased in a dose-dependent manner. Reactive oxygen species (ROS) scavengers and copper chelators inhibited the acrolein-mediated Cu,Zn-SOD modification and the formation of carbonyl compound. The present study shows that ROS may play a critical role in acrolein-induced Cu,Zn-SOD modification and inactivation. When Cu,Zn-SOD that has been exposed to acrolein was subsequently analyzed by amino acid analysis, serine, histidine, arginine, threonine and lysine residues were particularly sensitive. It is suggested that the modification and inactivation of Cu,Zn-SOD by acrolein could be produced by more oxidative cell environments.

  20. A superoxide dismutase/catalase mimetic nanomedicine for targeted therapy of inflammatory bowel disease.

    PubMed

    Zhang, Qixiong; Tao, Hui; Lin, Yongyao; Hu, Ying; An, Huijie; Zhang, Dinglin; Feng, Shibin; Hu, Houyuan; Wang, Ruibing; Li, Xiaohui; Zhang, Jianxiang

    2016-10-01

    Oxidative stress, resulting from excessive generation of reactive oxygen species (ROS), plays a pivotal role in the initiation and progression of inflammatory bowel disease (IBD). To develop an efficacious and safe nanotherapy against IBD, we designed and developed a superoxide dismutase/catalase mimetic nanomedicine comprising a hydrogen peroxide-eliminating nanomatrix and a free radical scavenger Tempol (Tpl). To this end, an oxidation-responsive β-cyclodextrin material (OxbCD) was synthesized, and a Tpl-loaded OxbCD nanoparticle (Tpl/OxbCD NP) was produced. Hydrolysis of OxbCD NP could be triggered by hydrogen peroxide, leading to on-demand release of loaded Tpl molecules from Tpl/OxbCD NP. OxbCD NP was able to efficiently accumulate in the inflamed colon in mice, thereby dramatically reducing nonspecific distribution after oral delivery. In three mouse colitis models, oral administration of Tpl/OxbCD NP notably mitigated manifestations relevant to colitis, and significantly suppressed expression of proinflammatory mediators, with the efficacy superior over free Tpl or a control nanomedicine based on poly(lactide-co-glycolide) (PLGA). Accordingly, by scavenging multiple components of ROS, Tpl/OxbCD NP may effectively reduce ulcerative colitis in mice, and it can be intensively developed as a translational nanomedicine for the management of IBD and other inflammatory diseases.

  1. Polydatin prevents angiotensin II-induced cardiac hypertrophy and myocardial superoxide generation

    PubMed Central

    Tan, Yingying; Zhang, Nan; Yao, Fanrong

    2015-01-01

    Our studies and others recently demonstrate that polydatin, a resveratrol glucoside, has antioxidative and cardioprotective effects. This study aims to investigate the direct effects of polydatin on Ang II-induced cardiac hypertrophy to explore the potential role of polydatin in cardioprotection. Our results showed that in primary cultured cardiomyocytes, polydatin blocked Ang II-induced cardiac hypertrophy in a dose-dependent manner, which were associated with reduction in the cell surface area and [3H]leucine incorporation, as well as attenuation of the mRNA expressions of atrial natriuretic factor and β-myosin heavy chain. Furthermore, polydatin prevented rat cardiac hypertrophy induced by Ang II infusion, as assessed by heart weight-to-body weight ratio, cross-sectional area of cardiomyocyte, and gene expression of hypertrophic markers. Further investigation demonstrated that polydatin attenuated the Ang II-induced increase in the reactive oxygen species levels and NADPH oxidase activity in vivo and in vitro. Polydatin also blocked the Ang II-stimulated increases of Nox4 and Nox2 expression in cultured cardiomyocytes and the hearts of Ang II-infused rats. Our results indicate that polydatin has the potential to protect against Ang II-mediated cardiac hypertrophy through suppression of NADPH oxidase activity and superoxide production. These observations may shed new light on the understanding of the cardioprotective effect of polydatin. PMID:25488910

  2. Copper-zinc superoxide dismutase-mediated redox regulation of bortezomib resistance in multiple myeloma.

    PubMed

    Salem, Kelley; McCormick, Michael L; Wendlandt, Erik; Zhan, Fenghuang; Goel, Apollina

    2015-01-01

    Multiple myeloma (MM) is an incurable B-cell malignancy. The proteasome inhibitor bortezomib (BTZ) is a frontline MM drug; however, intrinsic or acquired resistance to BTZ remains a clinical hurdle. As BTZ induces oxidative stress in MM cells, we queried if altered redox homeostasis promotes BTZ resistance. In primary human MM samples, increased gene expression of copper-zinc superoxide dismutase (CuZnSOD or SOD1) correlated with cancer progression, high-risk disease, and adverse overall and event-free survival outcomes. As an in vitro model, human MM cell lines (MM.1S, 8226, U266) and the BTZ-resistant (BR) lines (MM.1SBR, 8226BR) were utilized to determine the role of antioxidants in intrinsic or acquired BTZ-resistance. An up-regulation of CuZnSOD, glutathione peroxidase-1 (GPx-1), and glutathione (GSH) were associated with BTZ resistance and attenuated prooxidant production by BTZ. Enforced overexpression of SOD1 induced BTZ resistance and pharmacological inhibition of CuZnSOD with disulfiram (DSF) augmented BTZ cytotoxicity in both BTZ-sensitive and BTZ-resistant cell lines. Our data validates CuZnSOD as a novel therapeutic target in MM. We propose DSF as an adjuvant to BTZ in MM that is expected to overcome intrinsic and acquired BTZ resistance as well as augment BTZ cytotoxicity. PMID:25485927

  3. Genome-Wide Characterization and Expression Profiles of the Superoxide Dismutase Gene Family in Gossypium

    PubMed Central

    Zhang, Jingbo; Li, Bo; Yang, Yang; Hu, Wenran; Chen, Fangyuan; Xie, Lixia

    2016-01-01

    Superoxide dismutase (SOD) as a group of significant and ubiquitous enzymes plays a critical function in plant growth and development. Previously this gene family has been investigated in Arabidopsis and rice; it has not yet been characterized in cotton. In our study, it was the first time for us to perform a genome-wide analysis of SOD gene family in cotton. Our results showed that 10 genes of SOD gene family were identified in Gossypium arboreum and Gossypium raimondii, including 6 Cu-Zn-SODs, 2 Fe-SODs, and 2 Mn-SODs. The chromosomal distribution analysis revealed that SOD genes are distributed across 7 chromosomes in Gossypium arboreum and 8 chromosomes in Gossypium raimondii. Segmental duplication is predominant duplication event and major contributor for expansion of SOD gene family. Gene structure and protein structure analysis showed that SOD genes have conserved exon/intron arrangement and motif composition. Microarray-based expression analysis revealed that SOD genes have important function in abiotic stress. Moreover, the tissue-specific expression profile reveals the functional divergence of SOD genes in different organs development of cotton. Taken together, this study has imparted new insights into the putative functions of SOD gene family in cotton. Findings of the present investigation could help in understanding the role of SOD gene family in various aspects of the life cycle of cotton.

  4. Superoxide dismutase activity as a measure of hepatic oxidative stress in cattle following ethionine administration.

    PubMed

    Abd Ellah, Mahmoud R; Okada, Keiji; Goryo, Masanobu; Oishi, Akihiro; Yasuda, Jun

    2009-11-01

    The goal of this study was to assess if oxidative stress, as measured by alterations in the concentrations of antioxidant enzymes in the liver and erythrocytes of cattle, could be induced following dl-ethionine administration. Whole blood, serum and liver biopsy samples were collected 0, 4, 7 and 10 days after intra-peritoneal ethionine administration to five cows. The activities of the antioxidant enzymes copper zinc superoxide dismutase (Cu, Zn SOD) and catalase were assessed in the liver biopsies which were also examined histopathologically. Significant increases in hepatic Cu, Zn SOD concentrations (P<0.01) were noted on days 7 and 10 post-treatment. Hepatic catalase activity decreased significantly (P<0.01) on days 4, 7 and 10 post-treatment and erythrocyte Cu, Zn SOD activity was significantly increased on day 10. Serum biochemical analysis revealed a significant increase (P<0.01) in non-esterified fatty acid concentrations on day 4 and significant decreases in total cholesterol and phospholipid levels on days 4 (P<0.05), 7 (P<0.01) and 10 (P<0.01). In this model system, dl-ethionine administration was effective in inducing oxidative stress particularly reflected in the liver. PMID:18585936

  5. Interfacial Effects on Lithium Superoxide Disproportionation in Li-O₂ Batteries

    SciTech Connect

    Zhai, Dengyun; Lau, Kah Chun; Wang, Hsien-Hau; Wen, Jianguo; Miller, Dean; Lu, Jun; Kang, Feiyu; Li, Baohua; Yang, Wenge; Gao, Jing; Indacochea, Ernesto; Curtiss, Larry A.; Amine, Khalil

    2015-02-11

    During the cycling of Li-O₂ batteries the discharge process gives rise to dynamically evolving agglomerates composed of lithium-oxygen nanostructures; however, little is known about their composition. In this paper, we present results for a Li-O₂ battery based on an activated carbon cathode that indicate interfacial effects can suppress disproportionation of a LiO₂ component in the discharge product. High-intensity X-ray diffraction and transmission electron microscopy measurements are first used to show that there is a LiO₂ component along with Li₂O₂ in the discharge product. The stability of the discharge product was then probed by investigating the dependence of the charge potential and Raman intensity of the superoxide peak with time. The results indicate that the LiO₂ component can be stable for possibly up to days when an electrolyte is left on the surface of the discharged cathode. Density functional calculations on amorphous LiO₂ reveal that the disproportionation process will be slower at an electrolyte/LiO₂ interface compared to a vacuum/LiO₂ interface. The combined experimental and theoretical results provide new insight into how interfacial effects can stabilize LiO₂ and suggest that these interfacial effects may play an important role in the charge and discharge chemistries of a Li-O₂ battery.

  6. Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN.

    PubMed

    Singh, Karmveer; Maity, Pallab; Krug, Linda; Meyer, Patrick; Treiber, Nicolai; Lucas, Tanja; Basu, Abhijit; Kochanek, Stefan; Wlaschek, Meinhard; Geiger, Hartmut; Scharffetter-Kochanek, Karin

    2015-01-01

    The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions (O2∙-) in mitochondria, either by chemical inhibition of complex I or by genetic silencing of O2∙--dismutating mitochondrial Sod2. The O2∙--dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of α1(I), α1(III), and α2(I) collagen, the hallmarks of skin ageing. Enhanced O2∙- led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated O2∙--induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with O2∙-, PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies. PMID:25520316

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

    PubMed

    Zhu, Jia-Ying; Ze, Sang-Zi; Stanley, David W; Yang, Bin

    2014-09-01

    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. The cDNAs for ecCuZnSOD, icCuZnSOD, and MnSOD, respectively, encode 24.55, 15.81, and 23.14 kDa polypeptides, which possess structural features typical of other insect SODs. They showed 20-94% identity to other known SOD sequences from Bombyx mori, Musca domestica, Nasonia vitripennis, Pediculus humanus corporis, and Tribolium castaneum. Expression of these genes was analyzed in selected tissues and developmental stages, and following exposure to Escherichia coli and parasitization by Scleroderma guani. We recorded expression of all three SODs in cuticle, fat body, and hemocytes and in the major developmental stages. Relatively higher expressions were detected in late-instar larvae and pupae, compared to other developmental stages. Transcriptional levels were upregulated following bacterial infection. Analysis of pupae parasitized by S. guani revealed that expression of T. molitor SOD genes was significantly induced following parasitization. We infer that these genes act in immune response and in host-parasitoid interactions.

  8. Genome-Wide Characterization and Expression Profiles of the Superoxide Dismutase Gene Family in Gossypium

    PubMed Central

    Zhang, Jingbo; Li, Bo; Yang, Yang; Hu, Wenran; Chen, Fangyuan; Xie, Lixia

    2016-01-01

    Superoxide dismutase (SOD) as a group of significant and ubiquitous enzymes plays a critical function in plant growth and development. Previously this gene family has been investigated in Arabidopsis and rice; it has not yet been characterized in cotton. In our study, it was the first time for us to perform a genome-wide analysis of SOD gene family in cotton. Our results showed that 10 genes of SOD gene family were identified in Gossypium arboreum and Gossypium raimondii, including 6 Cu-Zn-SODs, 2 Fe-SODs, and 2 Mn-SODs. The chromosomal distribution analysis revealed that SOD genes are distributed across 7 chromosomes in Gossypium arboreum and 8 chromosomes in Gossypium raimondii. Segmental duplication is predominant duplication event and major contributor for expansion of SOD gene family. Gene structure and protein structure analysis showed that SOD genes have conserved exon/intron arrangement and motif composition. Microarray-based expression analysis revealed that SOD genes have important function in abiotic stress. Moreover, the tissue-specific expression profile reveals the functional divergence of SOD genes in different organs development of cotton. Taken together, this study has imparted new insights into the putative functions of SOD gene family in cotton. Findings of the present investigation could help in understanding the role of SOD gene family in various aspects of the life cycle of cotton. PMID:27660755

  9. Effects of copper supplementation on erythrocyte superoxide dismutase activity levels in rheumatoid arthritis patients

    SciTech Connect

    Marten, J.T.; DiSilvestro, R.A. )

    1989-02-09

    Rheumatoid arthritis (RA) patients are reported to possess lower than normal levels of Cu-Zn superoxide dismutase (SOD) activity. The contribution of copper status to these low values has not been examined. To address this issue, blood samples were obtained from 10 RA patients before and after 28 days of daily oral copper supplementation (2 mg/day). All patients were receiving gold therapy. Each RA subject, before supplementation, displayed lower erythrocyte SOD values than any of 25 age matched controls. The mean value for the RA subjects was about 40% lower than the control mean, whether expressed as units per ml packed cells or per mg hemoglobin. Erythrocyte SOD activity levels were increased in all subjects by the 4 week copper supplementation, with 7 of the patients showing at least a 22% increase. Presupplement SOD activities showed no correlation with serum C-reactive protein contents, an indicator of acute phase response. Serum levels of the copper containing acute phase protein ceruloplasmin, showed variable responses to copper supplementation. The studies described here are currently being extended to include RA subjects not being treated with gold and to include supplemented controls.

  10. Extracellular superoxide dismutase deficiency impairs wound healing in advanced age by reducing neovascularization and fibroblast function

    PubMed Central

    Fujiwara, Toshihiro; Duscher, Dominik; Rustad, Kristine C.; Kosaraju, Revanth; Rodrigues, Melanie; Whittam, Alexander J.; Januszyk, Michael; Maan, Zeshaan N.; Gurtner, Geoffrey C.

    2016-01-01

    Advanced age is characterized by impairments in wound healing, and evidence is accumulating that this may be due in part to a concomitant increase in oxidative stress. Extended exposure to reactive oxygen species (ROS) is thought to lead to cellular dysfunction and organismal death via the destructive oxidation of intra-cellular proteins, lipids and nucleic acids. Extracellular superoxide dismutase (ecSOD/SOD3) is a prime antioxidant enzyme in the extracellular space that eliminates ROS. Here, we demonstrate that reduced SOD3 levels contribute to healing impairments in aged mice. These impairments include delayed wound closure, reduced neovascularization, impaired fibroblast proliferation and increased neutrophil recruitment. We further establish that SOD3 KO and aged fibroblasts both display reduced production of TGF-β1, leading to decreased differentiation of fibroblasts into myofibroblasts. Taken together, these results suggest that wound healing impairments in ageing are associated with increased levels of ROS, decreased SOD3 expression and impaired extracellular oxidative stress regulation. Our results identify SOD3 as a possible target to correct age-related cellular dysfunction in wound healing. PMID:26663425

  11. Copper–zinc superoxide dismutase-mediated redox regulation of bortezomib resistance in multiple myeloma

    PubMed Central

    Salem, Kelley; McCormick, Michael L.; Wendlandt, Erik; Zhan, Fenghuang; Goel, Apollina

    2014-01-01

    Multiple myeloma (MM) is an incurable B-cell malignancy. The proteasome inhibitor bortezomib (BTZ) is a frontline MM drug; however, intrinsic or acquired resistance to BTZ remains a clinical hurdle. As BTZ induces oxidative stress in MM cells, we queried if altered redox homeostasis promotes BTZ resistance. In primary human MM samples, increased gene expression of copper–zinc superoxide dismutase (CuZnSOD or SOD1) correlated with cancer progression, high-risk disease, and adverse overall and event-free survival outcomes. As an in vitro model, human MM cell lines (MM.1S, 8226, U266) and the BTZ-resistant (BR) lines (MM.1SBR, 8226BR) were utilized to determine the role of antioxidants in intrinsic or acquired BTZ-resistance. An up-regulation of CuZnSOD, glutathione peroxidase-1 (GPx-1), and glutathione (GSH) were associated with BTZ resistance and attenuated prooxidant production by BTZ. Enforced overexpression of SOD1 induced BTZ resistance and pharmacological inhibition of CuZnSOD with disulfiram (DSF) augmented BTZ cytotoxicity in both BTZ-sensitive and BTZ-resistant cell lines. Our data validates CuZnSOD as a novel therapeutic target in MM. We propose DSF as an adjuvant to BTZ in MM that is expected to overcome intrinsic and acquired BTZ resistance as well as augment BTZ cytotoxicity. PMID:25485927

  12. Effects of histone acetylation on superoxide dismutase 1 gene expression in the pathogenesis of senile cataract

    PubMed Central

    Rong, Xianfang; Qiu, Xiaodi; Jiang, Yongxiang; Li, Dan; Xu, Jie; Zhang, Yinglei; Lu, Yi

    2016-01-01

    Histone acetylation plays key roles in gene expression, but its effects on superoxide dismutase 1 (SOD1) expression in senile cataract remains unknown. To address this problem, the study was to investigate the influence of histone acetylation on SOD1 expression and its effects in the pathogenesis of senile cataract. Senile cataract was classified into three types—nuclear cataract (NC), cortical cataract (CC), and posterior subcapsular cataract (SC)—using the Lens Opacities Classification System III. In senile cataracts, SOD1 expression decreased significantly. Both H3 and H4 were deacetylated at −600 bp of the SOD1 promoter of cataract lenses, and hypoacetylated at −1500, −1200, and −900 bp. In hypoacetylated histones, the hypoacetylation pattern differed among the cataracts. In vitro, anacardic acid (AA) significantly reduced H3 and H4 acetylation at the SOD1 promoter, decreased protein expression, and induced cataract formation in rabbits. AA also inhibited HLEC viability and increased cell apoptosis. In contrast, trichostatin A (TSA) was able to efficaciously stop AA’s effects on both rabbit lenses and HLECs. Decreased histone acetylation at the SOD1 promoter is associated with declined SOD1 expression in senile cataracts. Histone acetylation plays an essential role in the regulation of SOD1 expression and in the pathogenesis of senile cataracts. PMID:27703255

  13. Serum Superoxide Dismutase Is Associated with Vascular Structure and Function in Hypertensive and Diabetic Patients

    PubMed Central

    Gómez-Marcos, Manuel A.; Blázquez-Medela, Ana M.; Gamella-Pozuelo, Luis; Recio-Rodriguez, José I.; García-Ortiz, Luis; Martínez-Salgado, Carlos

    2016-01-01

    Oxidative stress is associated with cardiac and vascular defects leading to hypertension and atherosclerosis, being superoxide dismutase (SOD) one of the main intracellular antioxidant defence mechanisms. Although several parameters of vascular function and structure have a predictive value for cardiovascular morbidity-mortality in hypertensive patients, there are no studies on the involvement of SOD serum levels with these vascular parameters. Thus, we assessed if SOD serum levels are correlated with parameters of vascular function and structure and with cardiovascular risk in hypertensive and type 2 diabetic patients. We enrolled 255 consecutive hypertensive and diabetic patients and 52 nondiabetic and nonhypertensive controls. SOD levels were measured with an enzyme-linked immunosorbent assay kit. Vascular function and structure were evaluated by pulse wave velocity, augmentation index, ambulatory arterial stiffness index, and carotid intima-media thickness. We detected negative correlations between SOD and pressure wave velocity, peripheral and central augmentation index and ambulatory arterial stiffness index, pulse pressure, and plasma HDL-cholesterol, as well as positive correlations between SOD and plasma uric acid and triglycerides. Our study shows that SOD is a marker of cardiovascular alterations in hypertensive and diabetic patients, since changes in its serum levels are correlated with alterations in vascular structure and function. PMID:26635913

  14. Chronic retinal effects by ultraviolet irradiation, with special reference to superoxide dismutases.

    PubMed

    Oguni, M; Tamura, H; Kato, K; Setogawa, T

    1996-07-01

    Recently ultraviolet light (UV) reaching the Earth's surface has been gradually increasing in amounts by the destruction of the ozone layers. Large parts of UV are absorbed in the cornea and lens, and only a few amounts reached the retina; however, the effect on the retina is not fully elucidated. 38 rats were irradiated 0.5-5.0 J/cm2 UV from 6 to 50 times every 24 hours, and immunohistochemically and immunochemically for superoxide dismutases (SOD). Morphologically, the destruction of rod outer segments (ROS) and dissociation of cell membranes between the pigment epithelial cells (PE) were already observed by 6 times 0.5 J/cm2 UV irradiations. As the doses of UV increased, heterochromatins and lipid droplets increased in the PE. In normal retina, Cu/Zn SOD were mainly distributed from the inner limiting membrane (ILM) to the ganglion cell layer, and the PE; however, after 6 times 0.5 J/cm2 UV irradiations, the distribution became widened from inner to outer plexiform layer (OPL). At that time, the concentrations of Cu/Zn and Mn SOD increased in the retina. The present study reveals that the morphological damage caused by UV irradiation is observed in the ROS and PE, where no immunoreactivities could be detected to Cu/Zn and Mn SOD. However, morphological damage was not from the ILM to OPL, where the immunoreactivities to both Cu/Zn and Mn SOD were observed.

  15. Synthesis, crystal structure, superoxide scavenging activity, anticancer and docking studies of novel adamantyl nitroxide derivatives

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-he; Sun, Jin; Wang, Shan; Bu, Wei; Yao, Min-na; Gao, Kai; Song, Ying; Zhao, Jin-yi; Lu, Cheng-tao; Zhang, En-hu; Yang, Zhi-fu; Wen, Ai-dong

    2016-03-01

    A novel adamantyl nitroxide derivatives has been synthesized and characterized by IR, ESI-MS and elemental analysis. Quantum chemical calculations have also been performed to calculate the molecular geometry using density functional theory (B3LYP) with the 6-31G (d,p) basis set. The calculated results showed that the optimized geometry can well reproduce the crystal structure. The antioxidant and antiproliferative activity were evaluated by superoxide (NBT) and MTT assay. The adamantyl nitroxide derivatives exhibited stronger scavenging ability towards O2· - radicals when compared to Vitamin C, and demonstrated a remarked anticancer activity against all the tested cell lines, especially Bel-7404 cells with IC50 of 43.3 μM, compared to the positive control Sorafenib (IC50 = 92.0 μM). The results of molecular docking within EGFR using AutoDock confirmed that the titled compound favorably fitted into the ATP binding site of EGFR and would be a potential anticancer agent.

  16. Microglial neurotransmitter receptors trigger superoxide production in microglia; consequences for microglial-neuronal interactions.

    PubMed

    Mead, Emma L; Mosley, Angelina; Eaton, Simon; Dobson, Lucianne; Heales, Simon J; Pocock, Jennifer M

    2012-04-01

    Microglia express three isoforms of the NADPH oxidase, Nox1, Nox2 and Nox4, with the potential to produce superoxide (O(2) ˙(-) ). Microglia also express neurotransmitter receptors, which can modulate microglial responses. In this study, microglial activity of Nox1, Nox2 and Nox4 in primary rat cultured microglia or the rodent BV2 cell line were altered by microglial neurotransmitter receptor modulation. Glutamate, GABA or ATP triggered microglial O(2) ˙(-) production via Nox activation. Nox activation was elicited by agonists of metabotropic mGlu3 receptors and by group III receptors, by GABA(A) but not GABA(B) receptors, and by purinergic P2X(7) or P2Y(2/4) receptors but not P2Y(1) receptors, and inhibited by metabotropic glutamate receptor 5 antagonists. The neurotransmitters also modulated Nox mRNA expression and NADPH activity. The activation of Nox by BzATP or GABA promoted a neuroprotective phenotype whilst the activation of Nox by glutamate promoted a neurotoxic phenotype. Taken together, these data indicate that microglial neurotransmitter receptors can signal via Nox to promote neuroprotection or neurotoxicity. This has implications for the subsequent neurotoxic profile of microglia when neurotransmitter levels may become skewed in neurodegeneration. PMID:22243365

  17. Multiple phytoestrogens inhibit cell growth and confer cytoprotection by inducing manganese superoxide dismutase expression.

    PubMed

    Robb, Ellen L; Stuart, Jeffrey A

    2014-01-01

    Phytoestrogens are of interest because of their reported beneficial effects on many human maladies including cancer, neurodegeneration, cardiovascular disease and diabetes. As data on phytoestrogens continues to accumulate, it is clear that there is significant overlap in the cellular effects elicited by these various compounds. Here, we show that one mechanism by which a number of phytoestrogens achieve their growth inhibitory and cytoprotective effects is via induction of the mitochondrial manganese superoxide dismutase (MnSOD). Eight phytoestrogens, including resveratrol, coumestrol, kaempferol, genistein, daidzein, apigenin, isoliquirtigenin and glycitin, were tested for their ability to induce MnSOD expression in mouse C2C12 and primary myoblasts. Five of these, resveratrol, coumestrol, kaempferol, genistein and daidzein, significantly increased MnSOD expression, slowed proliferative growth and enhanced stress resistance (hydrogen peroxide LD50) . When siRNA was used to prevent the MnSOD induction by genistein, coumestrol or daidzein, none of these compounds exerted any effect on proliferative growth, and only the effect of coumestrol on stress resistance persisted. The estrogen antagonist ICI182780 prevented the increased MnSOD expression and also the changes in cell growth and stress resistance, indicating that these effects are mediated by estrogen receptors (ER). The absence of effects of resveratrol or coumestrol, but not genistein, in ERβ-null cells further indicated that this ER in particular is important in mediating these effects. Thus, an ER-mediated induction of MnSOD expression appears to underlie the growth inhibitory and cytoprotective activities of multiple phytoestrogens.

  18. A Superoxide Dismutase Maquette That Reproduces the Spectroscopic and Functional Properties of the Metalloenzyme

    SciTech Connect

    Shearer,J.; Long, L.

    2006-01-01

    Described herein is a nickel superoxide dismutase (NiSOD) maquette ([Ni(SOD{sup M1})]) based on the first 12 residues from the N-terminal sequence of Streptomyces coelicolor NiSOD. The apopeptide (SOD{sup M1}) was prepared by standard solid-phase Fmoc peptide synthesis. SOD{sup M1} will readily coordinate Ni{sup II} in a 1:1 ratio in slightly basic aqueous sodium phosphate buffer (0.1 M; pH = 7.2) forming a lightly colored beige/pink solution. Unlike NiSOD, which is isolated as a 1:1 mixture of oxidized (Ni{sup III}) and reduced (Ni{sup II}) forms, [Ni(SODM1)] can only be isolated in the NiII oxidation state. The UV/vis, X-ray absorption, and CD spectra of [Ni{sup II}(SOD{sup M1})] correspond well with those reported for the reduced form of NiSOD. Despite the fact that [Ni{sup III}(SOD{sup M1})] is not isolable, [Ni(SOD{sup M1})] has an appropriate redox potential to act as an SOD (E{sub 1/2} = 0.70(2) V vs. Ag/AgCl) and in fact will catalytically disproportionate >40 000 equiv of KO{sub 2}.

  19. Superoxide radical production and performance index of Photosystem II in leaves from magnetoprimed soybean seeds.

    PubMed

    Baby, Shine Madukakkuzhyil; Narayanaswamy, Guruprasad Kadur; Anand, Anjali

    2011-11-01

    Priming of soybean seeds with static magnetic field exposure of 200 mT (1 h) and 150 mT (1 h) resulted in plants with enhanced performance index (PI). The three components of PI i.e the density of reaction centers in the chlorophyll bed (RC/ABS), exciton trapped per photon absorbed (φpo) and efficiency with which a trapped exciton can move in electron transport chain (Ψo) were found to be 17%, 27% and 16% higher, respectively in leaves from 200 mT (1h) treated compared to untreated seeds. EPR spectrum of O2.--PBN adduct revealed that the O2.-radical level was lower by 16% in the leaves of plants that emerged from magnetic field treatment. Our study revealed that magnetoprimed seeds have a long lasting stimulatory effect on plants as reduced superoxide production and higher performance index contributed to higher efficiency of light harvesting that consequently increased biomass in plants that emerged from magnetoprimed seeds.

  20. Conformational Disorder of the Most Immature Cu, Zn-Superoxide Dismutase Leading to Amyotrophic Lateral Sclerosis.

    PubMed

    Furukawa, Yoshiaki; Anzai, Itsuki; Akiyama, Shuji; Imai, Mizue; Cruz, Fatima Joy C; Saio, Tomohide; Nagasawa, Kenichi; Nomura, Takao; Ishimori, Koichiro

    2016-02-19

    Misfolding of Cu,Zn-superoxide dismutase (SOD1) is a pathological change in the familial form of amyotrophic lateral sclerosis caused by mutations in the SOD1 gene. SOD1 is an enzyme that matures through the binding of copper and zinc ions and the formation of an intramolecular disulfide bond. Pathogenic mutations are proposed to retard the post-translational maturation, decrease the structural stability, and hence trigger the misfolding of SOD1 proteins. Despite this, a misfolded and potentially pathogenic conformation of immature SOD1 remains obscure. Here, we show significant and distinct conformational changes of apoSOD1 that occur only upon reduction of the intramolecular disulfide bond in solution. In particular, loop regions in SOD1 lose their restraint and become significantly disordered upon dissociation of metal ions and reduction of the disulfide bond. Such drastic changes in the solution structure of SOD1 may trigger misfolding and fibrillar aggregation observed as pathological changes in the familial form of amyotrophic lateral sclerosis.

  1. Kinetics of the oxidation of reduced Cu,Zn-superoxide dismutase by peroxymonocarbonate.

    PubMed

    Ranguelova, Kalina; Ganini, Douglas; Bonini, Marcelo G; London, Robert E; Mason, Ronald P

    2012-08-01

    Kinetic evidence is reported for the role of the peroxymonocarbonate, HOOCO(2)(-), as an oxidant for reduced Cu,Zn-superoxide dismutase-Cu(I) (SOD1) during the peroxidase activity of the enzyme. The formation of this reactive oxygen species results from the equilibrium between hydrogen peroxide and bicarbonate. Recently, peroxymonocarbonate has been proposed to be a key substrate for reduced SOD1 and has been shown to oxidize SOD1-Cu(I) to SOD1-Cu(II) much faster than H(2)O(2). We have reinvestigated the kinetics of the reaction between SOD1-Cu(I) and HOOCO(2)(-) by using conventional stopped-flow spectrophotometry and obtained a second-order rate constant of k=1600±100M(-1)s(-1) for SOD1-Cu(I) oxidation by HOOCO(2)(-). Our results demonstrate that peroxymonocarbonate oxidizes SOD1-Cu(I) to SOD1-Cu(II) and is in turn reduced to the carbonate anion radical. It is proposed that the dissociation of His61 from the active site Cu(I) in SOD-Cu(I) contributes to this chemistry by facilitating the binding of larger anions, such as peroxymonocarbonate. PMID:22569304

  2. Two superoxide dismutase prion strains transmit amyotrophic lateral sclerosis–like disease

    PubMed Central

    Bidhendi, Elaheh Ekhtiari; Bergh, Johan; Zetterström, Per; Andersen, Peter M.; Marklund, Stefan L.; Brännström, Thomas

    2016-01-01

    Amyotrophic lateral sclerosis (ALS) is an adult-onset degeneration of motor neurons that is commonly caused by mutations in the gene encoding superoxide dismutase 1 (SOD1). Both patients and Tg mice expressing mutant human SOD1 (hSOD1) develop aggregates of unknown importance. In Tg mice, 2 different strains of hSOD1 aggregates (denoted A and B) can arise; however, the role of these aggregates in disease pathogenesis has not been fully characterized. Here, minute amounts of strain A and B hSOD1 aggregate seeds that were prepared by centrifugation through a density cushion were inoculated into lumbar spinal cords of 100-day-old mice carrying a human SOD1 Tg. Mice seeded with A or B aggregates developed premature signs of ALS and became terminally ill after approximately 100 days, which is 200 days earlier than for mice that had not been inoculated or were given a control preparation. Concomitantly, exponentially growing strain A and B hSOD1 aggregations propagated rostrally throughout the spinal cord and brainstem. The phenotypes provoked by the A and B strains differed regarding progression rates, distribution, end-stage aggregate levels, and histopathology. Together, our data indicate that the aggregate strains are prions that transmit a templated, spreading aggregation of hSOD1, resulting in a fatal ALS-like disease. PMID:27140399

  3. Superoxide radical production and performance index of Photosystem II in leaves from magnetoprimed soybean seeds

    PubMed Central

    Baby, Shine Madukakkuzhyil; Narayanaswamy, Guruprasad Kadur; Anand, Anjali

    2011-01-01

    Priming of soybean seeds with static magnetic field exposure of 200 mT (1 h) and 150 mT (1 h) resulted in plants with enhanced performance index (PI). The three components of PI i.e the density of reaction centers in the chlorophyll bed (RC/ABS), exciton trapped per photon absorbed (φpo) and efficiency with which a trapped exciton can move in electron transport chain (Ψo) were found to be 17%, 27%  and 16% higher, respectively in leaves from 200 mT (1h) treated compared to untreated seeds.  EPR spectrum of  O2. – - PBN  adduct revealed that the O2. – radical level was lower by 16% in the leaves of plants that emerged from magnetic field treatment. Our study revealed that magnetoprimed seeds have a long lasting stimulatory effect on plants as reduced superoxide production and higher performance index contributed to higher efficiency of light harvesting that consequently increased biomass in plants from treated plants. PMID:22067104

  4. Oleuropein Prevents Neuronal Death, Mitigates Mitochondrial Superoxide Production and Modulates Autophagy in a Dopaminergic Cellular Model.

    PubMed

    Achour, Imène; Arel-Dubeau, Anne-Marie; Renaud, Justine; Legrand, Manon; Attard, Everaldo; Germain, Marc; Martinoli, Maria-Grazia

    2016-01-01

    Parkinson's disease (PD) is a progressive neurodegenerative disorder, primarily affecting dopaminergic neurons in the substantia nigra. There is currently no cure for PD and present medications aim to alleviate clinical symptoms, thus prevention remains the ideal strategy to reduce the prevalence of this disease. The goal of this study was to investigate whether oleuropein (OLE), the major phenolic compound in olive derivatives, may prevent neuronal degeneration in a cellular dopaminergic model of PD, differentiated PC12 cells exposed to the potent parkinsonian toxin 6-hydroxydopamine (6-OHDA). We also investigated OLE's ability to mitigate mitochondrial oxidative stress and modulate the autophagic flux. Our results obtained by measuring cytotoxicity and apoptotic events demonstrate that OLE significantly decreases neuronal death. OLE could also reduce mitochondrial production of reactive oxygen species resulting from blocking superoxide dismutase activity. Moreover, quantification of autophagic and acidic vesicles in the cytoplasm alongside expression of specific autophagic markers uncovered a regulatory role for OLE against autophagic flux impairment induced by bafilomycin A1. Altogether, our results define OLE as a neuroprotective, anti-oxidative and autophagy-regulating molecule, in a neuronal dopaminergic cellular model. PMID:27517912

  5. Superoxide dismutase activity as a measure of hepatic oxidative stress in cattle following ethionine administration.

    PubMed

    Abd Ellah, Mahmoud R; Okada, Keiji; Goryo, Masanobu; Oishi, Akihiro; Yasuda, Jun

    2009-11-01

    The goal of this study was to assess if oxidative stress, as measured by alterations in the concentrations of antioxidant enzymes in the liver and erythrocytes of cattle, could be induced following dl-ethionine administration. Whole blood, serum and liver biopsy samples were collected 0, 4, 7 and 10 days after intra-peritoneal ethionine administration to five cows. The activities of the antioxidant enzymes copper zinc superoxide dismutase (Cu, Zn SOD) and catalase were assessed in the liver biopsies which were also examined histopathologically. Significant increases in hepatic Cu, Zn SOD concentrations (P<0.01) were noted on days 7 and 10 post-treatment. Hepatic catalase activity decreased significantly (P<0.01) on days 4, 7 and 10 post-treatment and erythrocyte Cu, Zn SOD activity was significantly increased on day 10. Serum biochemical analysis revealed a significant increase (P<0.01) in non-esterified fatty acid concentrations on day 4 and significant decreases in total cholesterol and phospholipid levels on days 4 (P<0.05), 7 (P<0.01) and 10 (P<0.01). In this model system, dl-ethionine administration was effective in inducing oxidative stress particularly reflected in the liver.

  6. Fructose protects baker's yeast against peroxide stress: potential role of catalase and superoxide dismutase.

    PubMed

    Semchyshyn, Halyna M; Lozinska, Liudmyla M

    2012-11-01

    The negative effects of fructose due to its chronic consumption are well documented, while short-term application of fructose is found to protect different types of cells against oxidative stress. Reactive oxygen species (ROS) are suggested to mediate both the cytotoxic and defensive effects. Here, we compare the influence of glucose and fructose on yeast under H(2)O(2)-induced stress. Under control conditions, fructose-grown comparing with glucose-grown yeast demonstrated higher metabolic activity and ROS level. Therefore, fructose was suggested to provoke a mild stress that resulted in the acquisition of cellular resistance to lethal challenges, which explained the higher survival of fructose-grown yeast under H(2)O(2)-induced shock. Exposure to H(2)O(2) increased ROS level in glucose-grown cells, whereas it decreased the ROS level in fructose-grown cells. Hydrogen peroxide activated superoxide dismutase (SOD) and catalase in both the cell types studied, but glucose-grown cells demonstrated a sharp rise of the activities, while cells grown on fructose showed a broad peak of activation. Thus, fructose is likely to protect the antioxidant enzymes against their inactivation by H(2)O(2). Despite a different type of the enzyme activation in both the studied cell types (glucose- and fructose-grown), a strong positive correlation between SOD and catalase was found. The physiological meaning of this relationship and possible mechanisms of the fructose protective effect are discussed. PMID:22741594

  7. Fluorescence assay for monitoring Zn-deficient superoxide dismutase in vitro

    NASA Astrophysics Data System (ADS)

    Martyshkin, D. V.; Mirov, S. B.; Zhuang, Y.-X.; Crow, J. P.; Ermilov, V.; Beckman, J. S.

    2003-11-01

    A method has been developed for selective detection of the zinc-deficient form of Cu, Zn superoxide dismutase (SOD1) in vitro. Zinc-deficient SOD1 mutants have been implicated in the death of motor neurons leading in amyotrophic lateral sclerosis (ALS or Lou Gerhig's disease). Thus, this method may have applicability for detecting zinc-deficient SOD1 mutants in human ALS patients samples as well as in a transgenic mouse model of ALS and in cultured motor neurons. We determined previously that structural analogs of 1,10 phenanthroline, which react specifically with Cu(I), react with the active Cu(I) of SOD1 when zinc is absent, but not when zinc is also bound, as evidenced by the fact that the reaction is inhibited by pretreatment of the enzyme with zinc. We report herein that bathocuproine, or its water-soluble derivative bathocuproine disulfonate, react with zinc-deficient SOD1 to form a complex which fluoresces at 734 nm when excited at 482 nm. Fluorescent intensity is concentration dependent, thus we propose to use fluorescent confocal microscopy to measure intracellular levels of zinc-deficient SOD1 in situ.

  8. The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

    PubMed Central

    Herkovits, J.; D’Eramo, J. L.; Fridman, O.

    2006-01-01

    The exposure of Bufo arenarum embryos to 300–310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m2 was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m2 at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure. PMID:16823076

  9. Biochemical properties of Cu/Zn-superoxide dismutase from fungal strain Aspergillus niger 26

    NASA Astrophysics Data System (ADS)

    Dolashki, Aleksandar; Abrashev, Radoslav; Stevanovic, Stefan; Stefanova, Lilyana; Ali, Syed Abid; Velkova, Ludmila; Hristova, Rumyana; Angelova, Maria; Voelter, Wolfgang; Devreese, Bart; Van Beeumen, Jozef; Dolashka-Angelova, Pavlina

    2008-12-01

    The fungal strain Aspergillus niger produces two superoxide dismutases, Cu/Zn-SOD and Mn-SOD. The primary structure of the Cu/Zn-SOD has been determined by Edman degradation of peptide fragments derived from proteolytic digests. A single chain of the protein, consisting of 153 amino acid residues, reveals a very high degree of structural homology with the amino acid sequences of other Aspergillus Cu/Zn-SODs. The molecular mass of ANSOD, measured by MALDI-MS and ESI-MS, and calculated by its amino acid sequence, was determined to be 15 821 Da. Only one Trp residue, at position 32, and one disulfide bridge were identified. However, neither a Tyr residue nor a carbohydrate chain occupying an N-linkage site (-Asn-Ile-Thr-) were found. Studies on the temperature and pH dependence of fluorescence, and on the temperature dependence of CD spectroscopic properties, confirmed that the enzyme is very stable, which can be explained by the stabilising effect of the disulfide bridge. The enzyme retains about 53% of its activity after incubation for a period of 30 min at 60 °C, and 15% at 85 °C.

  10. Inhalation of Talc Induces Infiltration of Macrophages and Upregulation of Manganese Superoxide Dismutase in Rats.

    PubMed

    Shim, Ilseob; Kim, Hyun-Mi; Yang, Sangyoung; Choi, Min; Seo, Gyun-Baek; Lee, Byung-Woo; Yoon, Byung-Il; Kim, Pilje; Choi, Kyunghee

    2015-01-01

    Talc is a mineral that is widely used in cosmetic products, antiseptics, paints, and rubber manufacturing. Although the toxicological effects of talc have been studied extensively, until now no detailed inhalation study of talc focusing on oxidative stress has been done. This repeated 4 weeks whole-body inhalation toxicity study of talc involved Sprague-Dawley rats. Male and female groups of rats were exposed to inhaled talc at 0, 5, 50, and 100 mg/m(3) for 6 hours daily, 5 days/week for 4 weeks. The objective was to identify the 4-week inhalation toxicity of talc and investigate antioxidant activity after exposure to talc. There were no treatment-related symptoms or mortality in rats treated with talc. Glucose (GLU) was decreased significantly in male rats exposed to 50 and 100 mg/m(3) of talc. Histopathological examination revealed infiltration of macrophages on the alveolar walls and spaces near the terminal and respiratory bronchioles. In male and female rats exposed to 100 mg/m(3) talc, expression of superoxide dismutase 2, a typical biological indicator of oxidative damage, was significantly increased. Thus, inhalation of talc induces macrophage aggregations and oxidative damage in the lung. PMID:26482432

  11. 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. PMID:26846314

  12. Irradiation-resistance conferred by superoxide dismutase: possible adaptive role of a natural polymorphism in Drosophila melanogaster

    SciTech Connect

    Peng, T.X.; Moya, A.; Ayala, F.J.

    1986-02-01

    The toxic effects of ionizing radiation to DNA are thought to be due to the generation of the superoxide radical, 02-. Superoxide dismutase (SOD), which scavenges 02-., has been invoked as a protecting enzyme against ionizing radiation in viruses, bacteria, mammalian cells in culture, and live mice. We now demonstrate that SOD is involved in the resistance of Drosophila melanogaster against irradiation. The protection is greatest when flies carry the S form of the enzyme (which exhibits highest in vitro specific activity), intermediate when they carry the F form of the enzyme, and lowest when they are homozygous for N, an allele that reduces the amount of the enzyme to 3.5% of the normal level. Natural selection experiments show that the fitness of the high-activity S allele is increased in an irradiated population relative to the nonirradiated control. These results point towards a possible adaptive function of the S/F polymorphism found in natural populations of D. melanogaster.

  13. Inhibition of superoxide dismutase, Vitamin C and glutathione on chemiluminescence produced by luminol and the mixture of sulfite and bisulfite

    NASA Astrophysics Data System (ADS)

    Geng, Hong; Meng, Ziqiang

    2006-05-01

    In a system which consisted of luminol (3-aminophthalhydrazide), cobalt sulfate (CoSO 4), alkaline buffer and the mixture of NaSO 3 and sodium bisulfite (NaHSO 3) (sulfite and bisulfite = 3:1, m/m), a strong chemiluminescence (CL) was observed using a BPCL ultra-weak luminometer. The CL signals resulted from 3-aminophthalate (the product of oxidized luminol), and were affected by the buffer pH, buffer medium and the concentrations of luminol, CoSO 4 and the NaSO 3-NaHSO 3 mixture. The observation that the CL intensities were inhibited by superoxide dismutase (SOD), Vitamin C (Vc) and glutathione (GSH) in a dose-dependent manner suggested that superoxide radical (O 2rad -) was involved in the CL reaction and responsible for oxidation of luminol.

  14. Fc receptor-mediated phagocytosis, superoxide production and calcium signaling of beta 2 integrin-deficient bovine neutrophils.

    PubMed

    Nagahata, H; Sawada, C; Higuchi, H; Teraoka, H; Yamaguchi, M

    1997-01-01

    Fc receptor for immunoglobulin G-mediated phagocytosis, superoxide production and intracellular calcium ([Ca2+]i) signaling of complement receptor type 3 (CR3)-deficient neutrophils from a heifer with leukocyte adhesion deficiency (BLAD) were compared to those of control heifers. The mean phagocytic activity of IgG-coated yeasts and aggregated bovine IgG (Agg-IgG)-induced superoxide production of CR3-deficient neutrophils were 10% and 77.9%, respectively, of those of control neutrophils. The [Ca2+]i signals in CR3-deficient neutrophils stimulated with Agg-IgG or concanavalin A were different with mean peak [Ca2+]i concentrations of 78% and 41.9%, respectively, of those of control neutrophils. These findings suggest that Fc receptor-mediated neutrophil functions are closely dependent on the presence of CR3 (CD11b/CD18) on the neutrophil cell surfaces. PMID:9343828

  15. The effect of superoxide anion and hydrogen peroxide imbalance on prostate cancer: an integrative in vivo and in vitro analysis.

    PubMed

    Berto, Maiquidieli Dal; Bica, Claudia Giuliano; de Sá, Gustavo Pereira; Barbisan, Fernanda; Azzolin, Verônica Farina; Rogalski, Felipe; Duarte, Marta Maria Medeiros Frescura; da Cruz, Ivana Beatrice Mânica

    2015-11-01

    The epidemiological impact of SOD2 imbalance on prostate cancer (PC) risk associated with genetic variations has previously been studied. However, we found no previous studies clarifying the nature of SOD2 effects on prostate cancer. Here, we performed integrated in vivo and in vitro protocols that analyzed the association between Ala16Val-SOD2 polymorphism and prostate cancer aggressiveness at the time of diagnosis and evaluated the effect of the imbalance on PC proliferation using the DU-145 PC cell line treated with paraquat and porphyrin. In the pharmacological model, paraquat was used to increase superoxide anion levels and porphyrin was the SOD2 analog. The results confirmed the impact of superoxide-hydrogen peroxide imbalance on PC cell biology since porphyrin decreased cell proliferation and both treatments modulated antioxidant genes. Therefore, our results corroborate previous suggestions that alteration of redox status could be exploited therapeutically in the treatment of PC. PMID:26468117

  16. 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.

  17. High-throughput assays for superoxide and hydrogen peroxide: design of a screening workflow to identify inhibitors of NADPH oxidases.

    PubMed

    Zielonka, Jacek; Cheng, Gang; Zielonka, Monika; Ganesh, Thota; Sun, Aiming; Joseph, Joy; Michalski, Radosław; O'Brien, William J; Lambeth, J David; Kalyanaraman, Balaraman

    2014-06-01

    Recent progress characterizing the reaction mechanism(s) of fluorescent probes with reactive oxygen species has made it possible to rigorously analyze these reactive species in biological systems. We have developed rapid high throughput-compatible assays for monitoring cellular production of superoxide radical anion and hydrogen peroxide using hydropropidine and coumarin boronic acid probes, respectively. Coupling plate reader-based fluorescence measurements with HPLC-based simultaneous monitoring of superoxide radical anion and hydrogen peroxide provides the basis for the screening protocol for NADPH oxidase (Nox) inhibitors. Using this newly developed approach along with the medium-throughput plate reader-based oximetry and EPR spin trapping as confirmatory assays, it is now eminently feasible to rapidly and reliably identify Nox enzyme inhibitors with a markedly lower rate of false positives. These methodological advances provide an opportunity to discover selective inhibitors of Nox isozymes, through enhanced conceptual understanding of their basic mechanisms of action.

  18. 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.

  19. Rosmarinic acid and arbutin suppress osteoclast differentiation by inhibiting superoxide and NFATc1 downregulation in RAW 264.7 cells

    PubMed Central

    OMORI, AKINA; YOSHIMURA, YOSHITAKA; DEYAMA, YOSHIAKI; SUZUKI, KUNIAKI

    2015-01-01

    The present study investigated the effect of the natural polyphenols, rosmarinic acid and arbutin, on osteoclast differentiation in RAW 264.7 cells. Rosmarinic acid and arbutin suppressed osteoclast differentiation and had no cytotoxic effect on osteoclast precursor cells. Rosmarinic acid and arbutin inhibited superoxide production in a dose-dependent manner. mRNA expression of the master regulator of osteoclastogenesis, nuclear factor of activated T cells cytoplasmic 1 (NFATc1) and the osteoclast marker genes, matrix metalloproteinase-9, tartrate-resistant acid phosphatase and cathepsin-K, decreased following treatments with rosmarinic acid and arbutin. Furthermore, resorption activity decreased with the number of osteoclasts. These results suggest that rosmarinic acid and arbutin may be useful for the prevention and treatment of bone diseases, such as osteoporosis, through mechanisms involving inhibition of superoxide and downregulation of NFATc1. PMID:26171153

  20. 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.

  1. Oversynthesis of riboflavin in the yeast Pichia guilliermondii is accompanied by reduced catalase and superoxide dismutases activities.

    PubMed

    Prokopiv, Tetyana M; Fedorovych, Dariya V; Boretsky, Yuriy R; Sibirny, Andriy A

    2013-01-01

    Iron deficiency causes oversynthesis of riboflavin in several yeast species, known as flavinogenic yeasts. Under iron deprivation conditions, Pichia guilliermondii cells increase production of riboflavin and malondialdehyde and the formation of protein carbonyl groups, which reflect increased intracellular content of reactive oxygen species. In this study, we found that P. guilliermondii iron deprived cells showed dramatically decreased catalase and superoxide dismutase activities. Previously reported mutations rib80, rib81, and hit1, which affect repression of riboflavin synthesis and iron accumulation by iron ions, caused similar drops in activities of the mentioned enzymes. These findings could explain the previously described development of oxidative stress in iron deprived or mutated P. guilliermondii cells that overproduce riboflavin. Similar decrease in superoxide dismutase activities was observed in iron deprived cells in the non-flavinogenic yeast Saccharomyces cerevisiae. PMID:23053489

  2. Decreased expression of Cu-Zn superoxide dismutase 1 in ants with extreme lifespan.

    PubMed

    Parker, Joel D; Parker, Karen M; Sohal, Barbara H; Sohal, Rajindar S; Keller, Laurent

    2004-03-01

    Reactive oxygen species, the by-products of oxidative energy metabolism, are considered a main proximate cause of aging. Accordingly, overexpression of the enzyme Cu-Zn superoxide dismutase 1 (SOD1) can lengthen lifespan of Drosophila melanogaster in the laboratory. However, the role of SOD1 as a main determinant of lifespan has been challenged on the grounds that overexpression might be effective only in compromised genetic backgrounds. Moreover, interspecific comparisons show lower levels of antioxidant activities in longer-lived species, suggesting that life-span extension may evolve through less reactive oxygen species generation from the mitochondria rather than higher expression of SOD1. The tremendous variation in lifespan between ant castes, ranging over 2 orders of magnitude, coupled with the fact that all individuals share the same genome, provides a system to investigate the role of SOD1 in the wild. We used the ant Lasius niger as a model system, because queens can reach the extreme age of 28 years, whereas workers and males live only 1-2 years and a few weeks, respectively. We cloned SOD1 and found that long-lived queens have a lower level of expression than workers and males. Specific enzyme-activity assays also showed higher SOD1 activity levels in males and workers compared with queens, which had SOD1 activity levels similar to that of D. melanogaster. Altogether, these data show that increased expression of SOD1 is not required for the evolution of extreme lifespan, even in a system in which differential gene expression is the only way to express phenotypes with great lifespan differences.

  3. Unusual copper-induced sensitization of the biological damage due to superoxide radicals

    SciTech Connect

    Amram, S.; Mordechai, C.; Czapski, G.

    1981-12-01

    The role of superoxide radicals in biological damage in the presence of copper(II) ions has been investigated. Solutions of purified penicillinase in phosphate buffer, saturated with either air N/sub 2/, N/sub 2/O, or N/sub 2/O/O/sub 2/, were..gamma..-irradiated in the presence and in the absence of formate. The residual activity of the enzyme in catalyzing the cleavage of the..beta..-lactam ring of benzylpenicillin, was then monitored. The results indicate that in metal-free systems only the primary water-derived radicals, H,e/sub aq/, and OH, contribute toward enzyme inactivation, while the secondary species O/sub 2/ and CO/sub 2/ do not. The effect of copper(II) ions on the radiation-induced damage depended on which of the active species was predominant. With OH radicals, no effect of copper was detected. The damage originating from e/sub aq/ and H radicals decreased with the addition of copper, presumably due to their trapping by the copper(II) ions. In contrast, with O/sub 2/ radicals predominant in the system, copper dramatically enhanced the damage. This copper-induced sensitization was further increased in the presence of H/sub 2/O/sub 2/ and the dose modifying factor of copper exceeded 100, i.e. enchancement of the damage by two orders of magnitude, as compared with an oxygen enhancement ratio of 2-3 generally found for molecular oxygen. This copper effect could be completely eliminated by EDTA. The present results suggest that the presence of both transition metal ions and H/sub 2/O/sub 2/ and the binding of the metal ions to the target bimolecules are required for the manifestation.

  4. FUsed in Sarcoma Is a Novel Regulator of Manganese Superoxide Dismutase Gene Transcription

    PubMed Central

    Dhar, Sanjit Kumar; Zhang, Jiayu; Gal, Jozsef; Xu, Yong; Miao, Lu; Lynn, Bert C.; Zhu, Haining; Kasarskis, Edward J.

    2014-01-01

    Abstract Aims: FUsed in sarcoma (FUS) is a multifunctional DNA/RNA-binding protein that possesses diverse roles, such as RNA splicing, RNA transport, DNA repair, translation, and transcription. The network of enzymes and processes regulated by FUS is far from being fully described. In this study, we have focused on the mechanisms of FUS-regulated manganese superoxide dismutase (MnSOD) gene transcription. Results: Here we demonstrate that FUS is a component of the transcription complex that regulates the expression of MnSOD. Overexpression of FUS increased MnSOD expression in a dose-dependent manner and knockdown of FUS by siRNA led to the inhibition of MnSOD gene transcription. Reporter analyses, chromatin immunoprecipitation assay, electrophoretic mobility shift assay, affinity chromatography, and surface plasmon resonance analyses revealed the far upstream region of MnSOD promoter as an important target of FUS-mediated MnSOD transcription and confirmed that FUS binds to the MnSOD promoter and interacts with specificity protein 1 (Sp1). Importantly, overexpression of familial amyotropic lateral sclerosis (fALS)-linked R521G mutant FUS resulted in a significantly reduced level of MnSOD expression and activity, which is consistent with the decline in MnSOD activity observed in fibroblasts from fALS patients with the R521G mutation. R521G-mutant FUS abrogates MnSOD promoter-binding activity and interaction with Sp1. Innovation and Conclusion: This study identifies FUS as playing a critical role in MnSOD gene transcription and reveals a previously unrecognized relationship between MnSOD and mutant FUS in fALS. Antioxid. Redox Signal. 20, 1550–1566. PMID:23834335

  5. Catalase and superoxide dismutase activities as biomarkers of oxidative stress in workers exposed to mercury vapors

    SciTech Connect

    Perrin-Nadif, R.; Dusch, M.; Mur, J.M.; Koch, C.; Schmitt, P.

    1996-06-07

    We investigated the role of three blood antioxidant enzyme activities and total antioxidant status (TAS) as biological markers of oxidative stress in workers exposed to mercury (Hg{degrees}) vapors. Twenty-two female workers took part in the study. Blood and urine sampling for biological analyses was performed. The workers were classified into three subgroups according to their creatinine-corrected Hg concentration in urine. Blood antioxidant enzyme activities and TAS were compared between groups with nonparametric distribution-free methods. A significant difference existed in catalase activity and a slight, but not significant, difference existed in Cu{sup 2+}/Zn{sup 2+} superoxide dismutase (Cu{sup 2+}/Zn{sup 2+} SOD) activity between the three groups. No differences were observed in either the glutathione peroxidase activity or the TAS between these groups. Catalase and Cu{sup 2+}/Zn{sup 2+} SOD activities were increased in the groups of workers with higher creatinine-corrected urinary Hg concentrations when compared with the group of lower creatinine-corrected urinary Hg concentrations. Catalase activity was positively correlated with the creatinine-corrected concentration of Hg in urine, and Cu{sup 2+}/Zn{sup 2+} SOD activity was slightly correlated with the creatinine-corrected concentration of Hg in urine. The role of erythrocyte catalase and Cu{sup 2}/Zn{sup 2+} SOD activities we have measured is in agreement with the hypothesis of the involvement of reactive oxygen species production as an important event in chronic exposure to Hg{degrees} vapors in humans. In spite of the small sample size, results indicate that erythrocyte catalase and Cu{sup 2+}/Zn{sup 2+} SOD activities could be considered as markers of biological effect in workers exposed to Hg{degrees} vapors. 24 refs., 3 figs., 2 tabs.

  6. Effects of Cellular Pathway Disturbances on Misfolded Superoxide Dismutase-1 in Fibroblasts Derived from ALS Patients

    PubMed Central

    Keskin, Isil; Forsgren, Elin; Lange, Dale J.; Weber, Markus; Birve, Anna; Synofzik, Matthis; Gilthorpe, Jonathan D.; Andersen, Peter M.; Marklund, Stefan L.

    2016-01-01

    Mutations in superoxide dismutase-1 (SOD1) are a common known cause of amyotrophic lateral sclerosis (ALS). The neurotoxicity of mutant SOD1s is most likely caused by misfolded molecular species, but disease pathogenesis is still not understood. Proposed mechanisms include impaired mitochondrial function, induction of endoplasmic reticulum stress, reduction in the activities of the proteasome and autophagy, and the formation of neurotoxic aggregates. Here we examined whether perturbations in these cellular pathways in turn influence levels of misfolded SOD1 species, potentially amplifying neurotoxicity. For the study we used fibroblasts, which express SOD1 at physiological levels under regulation of the native promoter. The cells were derived from ALS patients expressing 9 different SOD1 mutants of widely variable molecular characteristics, as well as from patients carrying the GGGGCC-repeat-expansion in C9orf72 and from non-disease controls. A specific ELISA was used to quantify soluble, misfolded SOD1, and aggregated SOD1 was analysed by western blotting. Misfolded SOD1 was detected in all lines. Levels were found to be much lower in non-disease control and the non-SOD1 C9orf72 ALS lines. This enabled us to validate patient fibroblasts for use in subsequent perturbation studies. Mitochondrial inhibition, endoplasmic reticulum stress or autophagy inhibition did not affect soluble misfolded SOD1 and in most cases, detergent-resistant SOD1 aggregates were not detected. However, proteasome inhibition led to uniformly large increases in misfolded SOD1 levels in all cell lines and an increase in SOD1 aggregation in some. Thus the ubiquitin-proteasome pathway is a principal determinant of misfolded SOD1 levels in cells derived both from patients and controls and a decline in activity with aging could be one of the factors behind the mid-to late-life onset of inherited ALS. PMID:26919046

  7. Superoxide dismutase SodB is a protective antigen against Campylobacter jejuni colonisation in chickens.

    PubMed

    Chintoan-Uta, Cosmin; Cassady-Cain, Robin L; Al-Haideri, Halah; Watson, Eleanor; Kelly, David J; Smith, David G E; Sparks, Nick H C; Kaiser, Pete; Stevens, Mark P

    2015-11-17

    Campylobacter is the leading cause of foodborne diarrhoeal illness in the developed world and consumption or handling of contaminated poultry meat is the principal source of infection. Strategies to control Campylobacter in broilers prior to slaughter are urgently required and are predicted to limit the incidence of human campylobacteriosis. Towards this aim, a purified recombinant subunit vaccine based on the superoxide dismutase (SodB) protein of C. jejuni M1 was developed and tested in White Leghorn birds. Birds were vaccinated on the day of hatch and 14 days later with SodB fused to glutathione S-transferase (GST) or purified GST alone. Birds were challenged with C. jejuni M1 at 28 days of age and caecal Campylobacter counts determined at weekly intervals. Across three independent trials, the vaccine induced a statistically significant 1 log10 reduction in caecal Campylobacter numbers in vaccinated birds compared to age-matched GST-vaccinated controls. Significant induction of antigen-specific serum IgY was detected in all vaccinated birds, however the magnitude and timing of SodB-specific IgY did not correlate with lower numbers of C. jejuni. Antibodies from SodB-vaccinated chickens detected the protein in the periplasm and not membrane fractions or on the bacterial surface, suggesting that the protection observed may not be strictly antibody-mediated. SodB may be useful as a constituent of vaccines for control of C. jejuni infection in broiler birds, however modest protection was observed late relative to the life of broiler birds and further studies are required to potentiate the magnitude and timing of protection.

  8. Subcutaneous Administration of Bovine Superoxide Dismutase Protects Lungs from Radiation-Induced Lung Injury

    PubMed Central

    Jackson, Isabel L.; Vujaskovic, Zeljko

    2016-01-01

    Background The objective of the present study was to determine whether single administration of the antioxidant enzyme bovine superoxide dismutase (bSOD) after radiation (RT) exposure mitigates development of pulmonary toxicity in rats. Methods Female F344 rats (n=60) were divided among six experimental groups: (1) RT, single dose of 21 Gy to the right hemithorax; (2) RT+5 mg/kg bSOD; (3) RT+15 mg/kg bSOD; (4) No RT; (5) sham RT+5mg/kg bSOD; and (6) sham RT+15mg/kg bSOD. A single subcutaneous injection of bSOD (5 or 15 mg/kg) was administered 24 hours postradiation. The effects of bSOD on radiation-induced lung injury were assessed by measurement of body weight, breathing frequency and histopathological changes. Immunohistochemistry was used to evaluate oxidative stress (8-OHdG+, NOX4+, nitrotyrosine+, 4HNE+ cells), macrophage activation (ED1+), and expression of profibrotic TGF-β in irradiated tissue. Results Radiation led to an increase in all evaluated parameters. Treatment with 15mg/kg bSOD significantly decreased levels of all evaluated parameters including tissue damage and breathing frequency starting 6 weeks post-radiation. Animals treated with 5 mg/kg bSOD trended toward a suppression of radiation-induced lung damage but did not reach statistical significance. Conclusions The single application of bSOD (15mg/kg) ameliorates radiation induced lung injury through suppression of ROS/RNS dependent tissue damage. PMID:26110460

  9. Effects of Altered Levels of Extracellular Superoxide Dismutase and Irradiation on Hippocampal Neurogenesis in Female Mice

    SciTech Connect

    Zou, Yani; Leu, David; Chui, Jennifer; Fike, John R.; Huang, Ting-Ting

    2013-11-15

    Purpose: Altered levels of extracellular superoxide dismutase (EC-SOD) and cranial irradiation have been shown to affect hippocampal neurogenesis. However, previous studies were only conducted in male mice, and it was not clear if there was a difference between males and females. Therefore, female mice were studied and the results compared with those generated in male mice from an earlier study. Methods and Materials: Female wild-type, EC-SOD-null (KO), and EC-SOD bigenic mice with neuronal-specific expression of EC-SOD (OE) were subjected to a single dose of 5-Gy gamma rays to the head at 8 weeks of age. Progenitor cell proliferation, differentiation, and long-term survival of newborn neurons were determined. Results: Similar to results from male mice, EC-SOD deficiency and irradiation both resulted in significant reductions in mature newborn neurons in female mice. EC-SOD deficiency reduced long-term survival of newborn neurons whereas irradiation reduced progenitor cell proliferation. Overexpression of EC-SOD corrected the negative impacts from EC-SOD deficiency and irradiation and normalized the production of newborn neurons in OE mice. Expression of neurotrophic factors brain-derived neurotrophic factor and neurotrophin-3 were significantly reduced by irradiation in wild-type mice, but the levels were not changed in KO and OE mice even though both cohorts started out with a lower baseline level. Conclusion: In terms of hippocampal neurogenesis, EC-SOD deficiency and irradiation have the same overall effects in males and females at the age the studies were conducted.

  10. Mitochondrial Superoxide Signaling Contributes to Norepinephrine-Mediated T-Lymphocyte Cytokine Profiles

    PubMed Central

    Roessner, Colton T.; Tian, Jun; Zimmerman, Matthew C.

    2016-01-01

    Norepinephrine (NE) produces multifaceted regulatory patterns in T-lymphocytes. Recently, we have shown that NE utilizes redox signaling as evidenced by increased superoxide (O2●-) causally linked to the observed changes in these cells; however, the source of this reactive oxygen species (ROS) remains elusive. Herein, we hypothesized that the source of increased O2●- in NE-stimulated T-lymphocytes is due to disruption of mitochondrial bioenergetics. To address this hypothesis, we utilized purified mouse splenic CD4+ and CD8+ T-lymphocytes stimulated with NE and assessed O2●- levels, mitochondrial metabolism, cellular proliferation, and cytokine profiles. We demonstrate that the increase in O2●- levels in response to NE is time-dependent and occurs at later points of T-lymphocyte activation. Moreover, the source of O2●- was indeed the mitochondria as evidenced by enhanced MitoSOX Red oxidation as well as abrogation of this signal by the addition of the mitochondrial-targeted O2●--scavenging antioxidant MitoTempol. NE-stimulated T-lymphocytes also demonstrated decreased mitochondrial respiratory capacity, which suggests disruption of mitochondrial metabolism and the potential source of increased mitochondrial O2●-. The effects of NE in regards to redox signaling appear to be adrenergic receptor-dependent as specific receptor antagonists could reverse the increase in O2●-; however, differential receptors regulating these processes were observed in CD4+ versus CD8+ T-lymphocytes. Finally, mitochondrial O2●- was shown to be mechanistic to the NE-mediated T-lymphocyte phenotype as supplementation of MitoTempol could reverse specific changes in cytokine expression observed with NE treatment. Overall, these studies indicate that mitochondrial metabolism and O2●--mediated redox signaling play a regulatory role in the T-lymphocyte response to NE. PMID:27727316

  11. Sonochemiluminescence of lucigenin: Evidence of superoxide radical anion formation by ultrasonic irradiation

    NASA Astrophysics Data System (ADS)

    Matsuoka, Masanori; Takahashi, Fumiki; Asakura, Yoshiyuki; Jin, Jiye

    2016-07-01

    The sonochemiluminescence (SCL) behavior of lucigenin (Luc2+) has been studied in aqueous solutions irradiated with 500 kHz ultrasound. Compared with the SCL of a luminol system, a tremendously increased SCL intensity is observed from 50 µM Luc2+ aqueous solution (pH =11) when small amounts of coreactants such as 2-propanol coexist. It is shown that SCL intensity strongly depends on the presence of dissolved gases such as air, O2, N2, and Ar. The highest SCL intensity is obtained in an O2-saturated solution, indicating that molecular oxygen is required to generate SCL. Since SCL intensity is quenched completely in the presence of superoxide dismutase (SOD), an enzyme that can catalyze the disproportionation of O2 •-, the generation of O2 •- in the ultrasonic reaction field is important in the SCL of Luc2+. In this work, the evidence of O2 •- production is examined by a spectrofluorometric method using 2-(2-pyridyl)benzothiazoline as the fluorescent probe. The results indicate that the yield of O2 •- is markedly increased in the O2-saturated solutions when a small amount of 2-propanol coexists, which is consistent with the results of SCL measurements. 2-Propanol in the interfacial region of a cavitation bubble reacts with a hydroxyl radical (•OH) to form a 2-propanol radical, CH3C•(OH)CH3, which can subsequently react with dissolved oxygen to generate O2 •-. The most likely pathways for SCL as well as the spatial distribution of SCL in a microreactor are discussed in this study.

  12. Superoxide produced in the matrix of mitochondria enhances methylmercury toxicity in human neuroblastoma cells.

    PubMed

    Mailloux, Ryan J; Yumvihoze, Emmanuel; Chan, Hing Man

    2015-12-15

    The mechanism of intracellular metabolism of methylmercury (MeHg) is not fully known. It has been shown that superoxide (O2(-)), 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 O2(-)mediated degradation of MeHg in human neuroblastoma cells SH-K-SN. We also utilized paraquat (PQ) which generates O2(-) in the mitochondrial matrix. We found that the cleavage of the carbon-metal bond in MeHg was highly dependent on the topology of O2(-) production by mitochondria. Both rotenone and PQ, which increase O2(-) 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 O2(-) into the intermembrane space, did not have the same effect even though antimycin A induced a dose dependent increase in O2(-) 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 O2(-), specifically within the matrix of mitochondria when O2(-) is in adequate supply. Our results also show that O2(-) 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. PMID:26545714

  13. Superoxide produced in the matrix of mitochondria enhances methylmercury toxicity in human neuroblastoma cells.

    PubMed

    Mailloux, Ryan J; Yumvihoze, Emmanuel; Chan, Hing Man

    2015-12-15

    The mechanism of intracellular metabolism of methylmercury (MeHg) is not fully known. It has been shown that superoxide (O2(-)), 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 O2(-)mediated degradation of MeHg in human neuroblastoma cells SH-K-SN. We also utilized paraquat (PQ) which generates O2(-) in the mitochondrial matrix. We found that the cleavage of the carbon-metal bond in MeHg was highly dependent on the topology of O2(-) production by mitochondria. Both rotenone and PQ, which increase O2(-) 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 O2(-) into the intermembrane space, did not have the same effect even though antimycin A induced a dose dependent increase in O2(-) 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 O2(-), specifically within the matrix of mitochondria when O2(-) is in adequate supply. Our results also show that O2(-) 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.

  14. Azide protection of bacteroides superoxide dismutases from inactivation by hydrogen peroxide

    SciTech Connect

    Barkley, K.B.; Gregory, E.M.

    1986-05-01

    The anaerobes Bacteroides fragilis, B. distasonis and B. thetaiotaomicron produce an iron-containing superoxide dismutase (FeSOD). These FeSODs are reversibly inhibited by 1 mM azide (NaN/sub 3/) and are irreversibly inactivated upon incubation with hydrogen peroxide (H/sub 2/O/sub 2/). H/sub 2/O/sub 2/ inactivation of the enzyme likely depends on a Fenton type reaction with the production of hydroxyl radical (OH). Addition of NaN/sub 3/ to the enzyme solution decreased the rate of inactivation by H/sub 2/O/sub 2/. After 20 minutes incubation of purified B. distasonis FeSOD with 2.5 mM H/sub 2/O/sub 2/, 61% of the initial enzymatic activity remained when 1 mM NaN/sub 3/ was also present compared with 29% activity without NaN/sub 3/. Similar results were seen with FeSOD from B. fragilis and B. thetaiotaomicron. Metal analyses of the native, peroxidized, and NaN/sub 3/ protected samples are consistent with loss of Fe from the enzyme upon peroxidation, but retention of Fe and enzymatic activity in the NaN/sub 3/ protected sample. Protection of FeSOD activity from H/sub 2/O/sub 2/ inactivation was dependent on NaN/sub 3/ concentration. Anionic hydroxyl radical scavengers, such as urate and xanthine did not significantly protect the enzyme. The results are consistent with binding of azide to the active site either preventing entry of H/sub 2/O/sub 2/ or altering Fe redox potential, preventing OH production.

  15. Inhalation of ozone produces a decrease in superoxide anion radical production in mouse alveolar macrophages

    SciTech Connect

    Ryer-Powder, J.E.; Amoruso, M.A.; Czerniecki, B.; Witz, G.; Goldstein, B.D.

    1988-11-01

    The potentiation of fatal bacterial pneumonia in mice by prior inhalation of ozone occurs at levels of this oxidant pollutant that are frequently present in ambient air. A likely mechanism for this effect is an ozone-induced inhibition in the ability of pulmonary alveolar macrophages (PAM) to produce superoxide anion radical (O2-) demonstrated in the present study. A 25% decrease in PAM O2- production, as measured by nitroblue tetrazolium reduction, occurred after exposure of Swiss-Webster mice to 0.11 ppm ozone for 3 h (p less than 0.05). After 1 ppm there was almost complete inhibition of O2- release. In contrast, the rat, which is highly resistant to the potentiation of bacterial infections by ozone, was less sensitive to inhibition of PAM O2- production, as measured by cytochrome c reduction (mouse IC50, 0.41 ppm; rat IC50, 3.0 ppm ozone for 3 h). The observed decrement in mouse PAM O2- production was not associated with any change in phagocytic ability, as measured by both latex bead ingestion and 51Cr-labeled sheep red blood cell ingestion. This decrease in O2- production in the presence of normal phagocytic activity is analogous to certain of the findings in the neutrophils of children with chronic granulomatous disease. A decrease in rat PAM membrane cytochrome b558 levels was observed after ozone exposure of 3 ppm for 3 h, preliminarily suggesting that the mechanism by which ozone interferes with PAM O2- production may be through interaction with this heme-containing electron carrier.

  16. Development of a sarcoidosis murine lung granuloma model using Mycobacterium superoxide dismutase A peptide.

    PubMed

    Swaisgood, Carmen M; Oswald-Richter, Kyra; Moeller, Stephen D; Klemenc, Jennifer M; Ruple, Lisa M; Farver, Carol F; Drake, John M; Culver, Daniel A; Drake, Wonder P

    2011-02-01

    Sarcoidosis is characterized by noncaseating granulomas containing CD4(+) T cells with a Th1 immunophenotype. Although the causative antigens remain unknown, independent studies noted molecular and immunologic evidence of mycobacterial virulence factors in sarcoidosis specimens. A major limiting factor in discovering new insights into the pathogenesis of sarcoidosis is the lack of an animal model. Using a distinct superoxide dismutase A peptide (sodA) associated with sarcoidosis granulomas, we developed a pulmonary model of sarcoidosis granulomatous inflammation. Mice were sensitized by a subcutaneous injection of sodA, incorporated in incomplete Freund's adjuvant (IFA). Control subjects consisted of mice with no sensitization (ConNS), sensitized with IFA only (ConIFA), or with Schistosoma mansoni eggs. Fourteen days later, sensitized mice were challenged by tail-vein injection of naked beads, covalently coupled to sodA peptides or to schistosome egg antigens (SEA). Histologic analysis revealed hilar lymphadenopathy and noncaseating granulomas in the lungs of sodA-treated or SEA-treated mice. Flow cytometry of bronchoalveolar lavage (BAL) demonstrated CD4(+) T-cell responses against sodA peptide in the sodA-sensitized mice only. Cytometric bead analysis revealed significant differences in IL-2 and IFN-γ secretion in the BAL fluid of sodA-treated mice, compared with mice that received SEA or naked beads (P = 0.008, Wilcoxon rank sum test). ConNS and ConIFA mice demonstrated no significant formation of granuloma, and no Th1 immunophenotype. The use of microbial peptides distinct for sarcoidosis reveals a histologic and immunologic profile in the murine model that correlates well with those profiles noted in human sarcoidosis, providing the framework to investigate the molecular basis for the progression or resolution of sarcoidosis. PMID:20348207

  17. Interdisciplinary therapy changes superoxide dismutase activity and adiponectin in obese adolescents: a randomised controlled trial.

    PubMed

    Nunes, João Elias Dias; Cunha, Heitor Santos; Freitas, Zulmária Rezende; Nogueira, Ana Maria Caixeta; Dâmaso, Ana Raimunda; Espindola, Foued Salmen; Cheik, Nadia Carla

    2016-01-01

    The objective of this study is to evaluate the effect of interdisciplinary therapy in the parameters of the oxidative stress and the anti-inflammatory responses of obese adolescents. We selected 57 participants, who were randomly divided into 2 groups: interdisciplinary therapy group and a control group. After 6 months of intervention, 17 participants of the interdisciplinary therapy group and 8 of the control group returned for re-evaluation. The interdisciplinary therapy group participated in a treatment with 4 weekly sessions of exercise, a weekly group therapy session and a weekly nutritional education session. Blood parameters of oxidative stress and anti-inflammatory response were evaluated. The results demonstrated that there were significant increases in the interdisciplinary therapy group for superoxide dismutase activity (6.56 ± 3.22 to 11.40 ± 7.49) and ferric-reducing antioxidant potential concentration (532.91 ± 106.48 to 573.25 ± 112.57), although adiponectin levels did not reduce (40.9 ± 29.34 to 49.05 ± 41.22). A significant decrease i