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Sample records for superoxide generation termed

  1. Neutrophil superoxide-anion generating capacity in chronic smoking: effect of long-term alpha-tocopherol therapy

    NARCIS (Netherlands)

    Tits, van L.; Waart, de F.; Hak-Lemmers, H.L.M.; Graaf, de J.; Demacker, P.N.; Stalenhoef, A.F.

    2003-01-01

    We investigated whether long-term alpha-tocopherol therapy in chronic smoking affects superoxide generating capacity of neutrophils ex vivo. To this purpose, we randomly assigned 128 male chronic smokers (37 21 pack years of smoking) to treatment with placebo (n = 64) or alpha-tocopherol (400 IU

  2. Neutrophil superoxide-anion generating capacity in chronic smoking ...

    Indian Academy of Sciences (India)

    We investigated whether long-term -tocopherol therapy in chronic smoking affects superoxide generating capacity of neutrophils ex vivo. To this purpose, we randomly assigned 128 male chronic smokers (37 ± 21 pack years of smoking) to treatment with placebo ( = 64) or -tocopherol (400 IU dL--tocopherol daily, ...

  3. Neutrophil superoxide-anion generating capacity in chronic smoking ...

    Indian Academy of Sciences (India)

    Unknown

    To this purpose, we randomly assigned 128 male chronic smokers (37 ± 21 pack years of smoking) ... Secondly, in non-smoking human subjects we have recently shown ... therapy in chronic smoking affects superoxide generating capacity of ...

  4. Participation of superoxide generating system, superoxide dismutase and vitamin E in the radiation hazards

    International Nuclear Information System (INIS)

    Aono, Kaname; Yamamoto, Michio; Iida, Sosuke; Utsumi, Kozo

    1978-01-01

    In relation to the mechanism by which hemolysis was induced in radiated human erythrocytes in vitro, several inducements of membrane lipid peroxidation and protective effects of vitamin E (V.E) and superoxide dismutase (SOD) were investigated. (1) K + -release from erythrocytes was accelerated by radiation prior to hemolysis. These accelerated hemolysis and K + -release were protected remarkably by V.E and evidently by SOD. (2) Mitochondrial Fe 2+ induced and Fe 3+ -superoxide generating system -- ADP induced lipid peroxidation, and microsomal superoxide generating system -- induced lipid peroxidation were also protected by V.E and SOD. (3) Radiation of x-ray or 60 Co γ-ray accelerated lipid peroxidation of liver homogenate, microsome and liposome. Some of these accelerated lipid peroxidations were protected effectively by V.E and SOD. These results suggest that superoxide and/or OH generation by radiation induces of membrane lipid peroxidation, which leads deterioration of membrane resulting in the change of ion permeability and then hemolysis. (author)

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

    Science.gov (United States)

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

    2002-01-01

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

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

    Science.gov (United States)

    Sirota, T V

    2015-01-01

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

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

    Science.gov (United States)

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

    2018-03-01

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

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

    Science.gov (United States)

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

    2017-10-01

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

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

    Science.gov (United States)

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

    2018-01-01

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

  10. Induction of peroxide and superoxide protective enzymes and physiological cross-protection against peroxide killing by a superoxide generator in Vibrio harveyi.

    Science.gov (United States)

    Vattanaviboon, Paiboon; Panmanee, Warunya; Mongkolsuk, Skorn

    2003-04-11

    Vibrio harveyi is a causative agent of destructive luminous vibriosis in farmed black tiger prawn (Penaeus monodon). V. harveyi peroxide and superoxide stress responses toward elevated levels of a superoxide generated by menadione were investigated. Exposure of V. harveyi to sub-lethal concentrations of menadione induced high expression of genes in both the OxyR regulon (e.g., a monofunctional catalase or KatA and an alkyl hydroperoxide reductase subunit C or AhpC), and the SoxRS regulon (e.g., a superoxide dismutase (SOD) and a glucose-6-phosphate dehydrogenase). V. harveyi expressed two detectable, differentially regulated SOD isozymes, [Mn]-SOD and [Fe]-SOD. [Fe]-SOD was expressed constitutively throughout the growth phase while [Mn]-SOD was expressed at the stationary phase and could be induced by a superoxide generator. Physiologically, pre-treatment of V. harveyi with menadione induced cross-protection against subsequent exposure to killing concentrations of H(2)O(2). This induced cross-protection required newly synthesized proteins. However, the treatment did not induce significant protection against exposures to killing concentrations of menadione itself or cross-protect against an organic hydroperoxide (tert-butyl hydroperoxide). Unexpectedly, growing V. harveyi in high-salinity media induced protection against menadione killing. This protection was independent of SOD induction. Stationary-phase cells were more resistant to menadione killing than exponential-phase cells. The induction of oxidative stress protective enzymes and stress-altered physiological responses could play a role in the survival of this bacterium in the host marine crustaceans.

  11. Metal bacteriochlorins which act as dual singlet oxygen and superoxide generators.

    Science.gov (United States)

    Fukuzumi, Shunichi; Ohkubo, Kei; Zheng, Xiang; Chen, Yihui; Pandey, Ravindra K; Zhan, Riqiang; Kadish, Karl M

    2008-03-06

    A series of stable free-base, Zn(II) and Pd(II) bacteriochlorins containing a fused six- or five-member diketo- or imide ring have been synthesized as good candidates for photodynamic therapy sensitizers, and their electrochemical, photophysical, and photochemical properties were examined. Photoexcitation of the palladium bacteriochlorin affords the triplet excited state without fluorescence emission, resulting in formation of singlet oxygen with a high quantum yield due to the heavy atom effect of palladium. Electrochemical studies revealed that the zinc bacteriochlorin has the smallest HOMO-LUMO gap of the investigated compounds, and this value is significantly lower than the triplet excited-state energy of the compound in benzonitrile. Such a small HOMO-LUMO gap of the zinc bacteriochlorin enables intermolecular photoinduced electron transfer from the triplet excited state to the ground state to produce both the radical cation and the radical anion. The radical anion thus produced can transfer an electron to molecular oxygen to produce superoxide anion which was detected by electron spin resonance. The same photosensitizer can also act as an efficient singlet oxygen generator. Thus, the same zinc bacteriochlorin can function as a sensitizer with a dual role in that it produces both singlet oxygen and superoxide anion in an aprotic solvent (benzonitrile).

  12. Effect of fluticasone propionate on neutrophil chemotaxis, superoxide generation, and extracellular proteolytic activity in vitro.

    Science.gov (United States)

    Llewellyn-Jones, C G; Hill, S L; Stockley, R A

    1994-03-01

    Corticosteroids are widely used in the treatment of many inflammatory conditions but the exact mode of action on neutrophil function is uncertain. Fluticasone propionate is a new topically active synthetic steroid which can be measured in body fluids and which undergoes first pass metabolism. The effects of fluticasone propionate on the function of neutrophils isolated from normal, healthy control subjects and on the chemotactic activity of sputum sol phase were assessed. Preincubation of neutrophils with fluticasone propionate reduced the chemotactic response to 10(-8) mol/l F-Met-Leu-Phe (FMLP) and to a 1:5 dilution of sputum sol phase in a dose dependent manner. Furthermore, when fluticasone propionate was added to sputum from eight patients with stable chronic obstructive bronchitis the chemotactic activity of a 1:5 dilution of the sol phase fell from a mean (SE) value of 22.2 (1.21) cells/field to 19.6 (0.89), 17.1 (0.74), and 11.9 (0.6) cells field at 1 mumol/l, 10 mumol/l, and 100 mumol/l, respectively. In further experiments fluticasone propionate preincubated with neutrophils inhibited fibronectin degradation by resting cells and by cells stimulated by FMLP (15.2% inhibition of resting cells, 5.1% inhibition of stimulated cells with 1 mumol/l fluticasone propionate, 24% and 18.7% inhibition respectively at 100 mumol/l fluticasone propionate. Fluticasone propionate had no effect on generation of superoxide anion by resting or stimulated cells. These results indicate that fluticasone propionate has a direct suppressive effect on several aspects of neutrophil function and may suggest a role for this agent in the modulation of neutrophil mediated damage to connective tissue.

  13. Superoxide generation is diminished during glucose-stimulated insulin secretion in INS-1E cells

    Czech Academy of Sciences Publication Activity Database

    Ježek, Petr; Hlavatá, Lydie; Špaček, Tomáš

    2008-01-01

    Roč. 275, Suppl.1 (2008), s. 310-310 ISSN 1742-464X. [FEBS Congress /33./ and IUBMB Conference /11./. 28.06.2008-03.07.2008, Athens] R&D Projects: GA MZd(CZ) NR7917; GA AV ČR(CZ) IAA500110701 Institutional research plan: CEZ:AV0Z50110509 Keywords : cpo1 * superoxide production * glucose-stimulated insulin secretion * INS-1E cells Subject RIV: ED - Physiology

  14. (-)-Xanthienopyran, a new inhibitor of superoxide anion generation by activated neutrophils, and further constituents of the seeds of Xanthium strumarium.

    Science.gov (United States)

    Lee, Chia-Lin; Huang, Po-Ching; Hsieh, Pei-Wen; Hwang, Tsong-Long; Hou, Yu-Yi; Chang, Fang-Rong; Wu, Yang-Chang

    2008-08-01

    The dried seeds of XANTHIUM STRUMARIUM (Asteraceae) are used after thorough stir-frying as an ingredient in traditional Chinese medicines for relieving allergy. Two new compounds, xanthialdehyde ( 2) and (-)-xanthienopyran ( 7), as well as 26 known compounds were isolated in the present study. The structures of the isolates were elucidated by spectroscopic methods. Among them, compound 7 exhibited significant selective inhibition of superoxide anion generation by human neutrophils induced by formyl- L-methionyl- L-leucyl- L-phenylalanine, with an IC50 value of 1.72 microg/mL.

  15. Superoxide Dismutase: A Predicting Factor for Boar Semen Characteristics for Short-Term Preservation

    Science.gov (United States)

    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 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 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. The activity of 3- and 7-hydroxyflavones as scavengers of superoxide radical anion generated from photo-excited riboflavin

    International Nuclear Information System (INIS)

    Montana, P.; Pappano, N.; Debattista, N.; Avila, V.; Posadaz, A.; Bertolotti, S.G.; Garcia, N.A.

    2003-01-01

    The visible-light irradiation of the system Riboflavin plus 3-hydroxyflavone or plus 7-hydroxyflavone, under aerobic conditions, produces a series of competitive processes that depend on the relative concentrations of the pigment and the flavones. The picture comprises photochemical mechanisms that potentially operate in nature. They mainly include the quenching of Rf singlet ( 1 Rf*) and triplet ( 3 Rf*) excited states (with bimolecular rate constants in the order of 10 9 M -1 s -1 ) and superoxide radical anion-mediated reactions. The participation of the oxidative species singlet molecular oxygen was not detected. The overall result shows chemical transformations in both Rf and 3-hydroxyflavone. No experimental evidence was found indicating any chemical reaction involving 7-hydroxyflavone. The fate of the pigment also depends on the amount of the dissolved flavonoid. At 50 mM concentrations of these compounds or higher, practically no photochemistry occurs, owing to the extensive quenching of ( 1 Rf*) When the concentration of the flavones is in the mM range or lower, ( 3 Rf*) is photogenerated. Then, the excited triplet species can be quenched mainly by the flavones through an electron-transfer process, yielding the semireduced pigment. The latter interacts with dissolved oxygen producing O 2 .- , which reacts with both the pigment and 3-hydroxyflavone. In summary, 3-hydroxyflavone and 7-hydroxyflavone participate in the generation of superoxide ion in an Rf-sensitized process, and simultaneously 3-hydroxyflavone constitutes a degradable quencher of the oxidative species. (author)

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

    Directory of Open Access Journals (Sweden)

    Alejandro K. Samhan-Arias

    2018-05-01

    Full Text Available In this work, we measured the effect of cytochrome c on the NADH-dependent superoxide anion production by synaptic plasma membrane vesicles from rat brain. In these membranes, the cytochrome c stimulated NADH-dependent superoxide anion production was inhibited by antibodies against cytochrome b5 reductase linking the production to this enzyme. Measurement of the superoxide anion radical generated by purified recombinant soluble and membrane cytochrome b5 reductase corroborates the production of the radical by different enzyme isoforms. In the presence of cytochrome c, a burst of superoxide anion as well as the reduction of cytochrome c by cytochrome b5 reductase was measured. Complex formation between both proteins suggests that cytochrome b5 reductase is one of the major partners of cytochrome c upon its release from mitochondria to the cytosol during apoptosis. Superoxide anion production and cytochrome c reduction are the consequences of the stimulated NADH consumption by cytochrome b5 reductase upon complex formation with cytochrome c and suggest a major role of this enzyme as an anti-apoptotic protein during cell death.

  18. A non-invasive and rapid seed vigor biosensor based on quantitative measurement of superoxide generated by aleurone cell in intact seeds.

    Science.gov (United States)

    Liu, Xuejun; Gao, Caiji; Xing, Da

    2009-02-15

    Superoxide generated during the early imbibition is an excellent marker for evaluating seed vigor. In this paper, a new principle biosensor for non-invasive detection of seed vigor based on quantitative measurement of superoxide via selective probe 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo [1,2alpha] pyrazin-3-one (MCLA)-mediated chemiluminescence (CL) was developed. The biosensor, which used a compact single-photon counting module (SPCM) to collect the CL signal, could evaluate seed vigor in vivo. Benefiting from the high CL efficiency of MCLA reacting with superoxide and high sensitivity of the SPCM technique, the trace superoxide generated by dry seeds under storage state can be detected to achieve rapid and non-invasive determination of the seed vigor. In comparison with the traditional methods for fast measuring seed vigor based on measurement of physiological and biochemical properties, our proposed technique has significant advantages such as low cost, simplicity, convenient operation and short time consuming. To demonstrate the utility of the system, it was applied to evaluate MCLA-mediated CL of three different plant species wheat (Ze Yu No. 2), maize (Tai Gu No. 1 and 2) and rice (Jing Dao No. 21) seeds with different degrees of aging. The experimental results suggested that there was an excellent positive correlation between the seed vigor assessment from quantitative TTC-test and the detection based on MCLA-mediated CL of superoxide measurement. The new principle of seed vigor measurement is a challenge and breakthrough to conventional method of seed vigor determination and may be a potential technique of the next generation seed vigor detection.

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

    Science.gov (United States)

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

    2016-01-01

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

  20. Understanding Free Radicals: Isolating Active Thylakoid Membranes and Purifying the Cytochrome b6f Complex for Superoxide Generation Studies

    Directory of Open Access Journals (Sweden)

    Jason Stofleth

    2012-01-01

    Full Text Available All life persists in an environment that is rich in molecular oxygen. The production of oxygen free radicals, or superoxide, is a necessary consequence of the biogenesis of energy in cells. Both mitochondrial and photosynthetic electron transport chains have been found to produce superoxide associated with cell differentiation, proliferation, and cell death, thereby contributing to the effects of aging. Aerobic respiration in mitochondria consumes oxygen, whereas photosynthesis in chloroplasts or cyanobacteria produces oxygen. The increased concentration of molecular oxygen may serve to allow greater availability for the production of superoxide by cytochrome bc complexes in photosynthetic membranes compared to those of mitochondrial membranes. The isolation of well-coupled chloroplasts, containing the cytochrome b6f complex of oxygenic photosynthesis, is a vital initial step in the process of comparing the rate of production of superoxide to those of the homologous cytochrome bc1 complex of aerobic respiration. It is necessary to determine if the isolated chloroplasts have retained their oxygengenerating capability after isolation by an oxygen evolution assay with a Clark-type electrode. A necessary second step, which is the isolation of cytochrome b6f from spinach, has yet to be successfully performed. Oxygen measurements taken from chloroplasts in the presence of the uncoupler, NH4Cl, exhibited a rate of oxygen evolution over three times greater at 344 +/- 18 μmol O2/mg Chlorophyll a/hr than the rate of oxygen evolution without uncoupler at 109 +/- 29 μmol O2/mg Chlorophyll a/hr. These data demonstrate that the technique used to isolate spinach chloroplasts preserves their light-driven electron-transport activity, making them reliable for future superoxide assays.

  1. The Term Processor Generator Kimwitu

    NARCIS (Netherlands)

    van Eijk, P.H.J.; van Eijk, Peter; Belinfante, Axel; Eertink, E.H.; Eertink, Henk; Alblas, H.; Brinksma, Hendrik

    The Kimwitu system is a meta-tool that supports the construction of programs (tools) that operate on trees or terms. The system supports open multi-paradigm programming, in that it allows to express each part of an implementation in the most appropriate language. Terms can be implemented in a tool

  2. [Standardization and regulation of the rate of the superoxide-generating adrenaline autoxidation reaction used for evaluation of pro/antioxidant properties of various materials].

    Science.gov (United States)

    Sirota, T V

    2016-11-01

    The superoxide-generating reaction of adrenaline autoxidation is widely used for determination of the activity of superoxide dismutase and pro/antioxidant properties of various materials. There are two variants of the spectrophotometric registration of the products of this reaction. The first is based on registration of adrenochrome, as adrenaline autooxidation product at 347 nm; the second employs nitro blue tetrazolium (NBT) and registration of diformazan, a product of NBT reduction at 560 nm. In the present work, recommendations for the standardization of the reaction rate in both variants have been proposed. The main approach consists in the use of the pharmaceutical form of 0.1% adrenaline hydrochloride solution. Although each of two adrenaline preparations available in the Russian market has some features in kinetic behavior of its autooxidation; they are applicable in the superoxide generating system based on adrenaline autooxidation. Performing measurements at 560 nm, the reaction rate can be regulated by lowering the concentration of added adrenaline, whereas during spectrophotometric registration at 347 nm, this cannot be done. These features of adrenaline autoxidation may be due to the fact that the intrinsic multistage process of the conversion of adrenaline to adrenochrome, which is recorded at 347 nm, is coupled with the transition of electrons from adrenaline and intermediate products of its oxidation to oxygen, carbon dioxide, and carbonate bicarbonate ions, which is detected in the presence of added NBT.

  3. Zinc and magnesium ions synergistically inhibit superoxide generation by cultured human neutrophils--a promising candidate formulation for amnioinfusion fluid.

    Science.gov (United States)

    Uchida, Toshiyuki; Itoh, Hiroaki; Nakamura, Yuki; Kobayashi, Yukiko; Hirai, Kyuya; Suzuki, Kazunao; Sugihara, Kazuhiro; Kanayama, Naohiro; Hiramatsu, Mitsuo

    2010-06-01

    Oligohydramnios is often caused by the premature rupturing of membranes and subsequent intrauterine infections, such as chorioamnionitis, in which event oxidative stress is hypothesized to be closely associated with the damage to the fetal organs. The clinical efficiency of amnioinfusion using warmed saline in cases of premature rupture of membranes is still controversial, especially concerning the prognosis for the fetus. In the present study, we found that human amniotic fluid per se suppresses the release of superoxide from cultured human neutrophils, suggesting an acute or chronic shortage of amniotic fluid in cases of premature rupture of membranes can affect the shielding of intrauterine organs from oxidative stress. The aim of this study was to propose a formula of zinc and magnesium ions in saline for amnioinfusion, by assessing antioxidative activities. A combination of 5 microM zinc and 5mM magnesium in saline synergistically inhibited superoxide production by cultured human neutrophils, equivalent to human amniotic fluid. The intraperitoneal administration of this formula significantly improved the survival rate in a rat model of peritonitis compared to the saline control (46.7% vs. 10%). The combination of these metals with saline may thus be a promising formula for an amnioinfusion fluid with the capacity to protect fetal organs from oxidative stress. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

  4. Eunicellin-based diterpenoids from the Formosan soft coral Klyxum molle with inhibitory activity on superoxide generation and elastase release by neutrophils.

    Science.gov (United States)

    Lin, Ming-Chang; Chen, Bo-Wei; Huang, Chiung-Yao; Dai, Chang-Feng; Hwang, Tsong-Long; Sheu, Jyh-Horng

    2013-09-27

    Eleven new eunicellin-based diterpenoids possessing a cladiellane skeleton with a C-2, C-9 ether bridge, klymollins I-S (1-11), have been isolated from the EtOAc extract of the soft coral Klyxum molle from Taiwan waters. The structures of compounds 1-11 were elucidated by extensive spectroscopic analysis, including 2D NMR spectroscopy (COSY, HSQC, HMBC, and NOESY). Compound 5 exhibited cytotoxicity toward several cancer cell lines. Compound 5 is the first eunicellin-based metabolite bearing a phenyl group and displays significant inhibition of both superoxide anion generation and elastase release in N-formyl-methionyl-leucyl-phenylalanine/cytochalasin B (fMLP/CB)-induced human neutrophils.

  5. Ca2+ and Mg2+-enhanced reduction of arsenazo III to its anion free radical metabolite and generation of superoxide anion by an outer mitochondrial membrane azoreductase.

    Science.gov (United States)

    Moreno, S N; Mason, R P; Docampo, R

    1984-12-10

    At the concentrations usually employed as a Ca2+ indicator, arsenazo III underwent a one-electron reduction by rat liver mitochondria to produce an azo anion radical as demonstrated by electron-spin resonance spectroscopy. Either NADH or NADPH could serve as a source of reducing equivalents for the production of this free radical by intact rat liver mitochondria. Under aerobic conditions, addition of arsenazo III to rat liver mitochondria produced an increase in electron flow from NAD(P)H to molecular oxygen, generating superoxide anion. NAD(P)H generated from endogenous mitochondrial NAD(P)+ by intramitochondrial reactions could not be used for the NAD(P)H azoreductase reaction unless the mitochondria were solubilized by detergent or anaerobiosis. In addition, NAD(P)H azoreductase activity was higher in the crude outer mitochondrial membrane fraction than in mitoplasts and intact mitochondria. The steady-state concentration of the azo anion radical and the arsenazo III-stimulated cyanide-insensitive oxygen consumption were enhanced by calcium and magnesium, suggesting that, in addition to an enhanced azo anion radical-stabilization by complexation with the metal ions, enhanced reduction of arsenazo III also occurred. Accordingly, addition of cations to crude outer mitochondrial membrane preparations increased arsenazo III-stimulated cyanide-insensitive O2 consumption, H2O2 formation, and NAD(P)H oxidation. Antipyrylazo III was much less effective than arsenazo III in increasing superoxide anion formation by rat liver mitochondria and gave a much weaker electron spin resonance spectrum of an azo anion radical. These results provide direct evidence of an azoreductase activity associated with the outer mitochondrial membrane and of a stimulation of arsenazo III reduction by cations.

  6. Diminished superoxide generation is associated with respiratory chain dysfunction and changes in the mitochondrial proteome of sensory neurons from diabetic rats.

    Science.gov (United States)

    Akude, Eli; Zherebitskaya, Elena; Chowdhury, Subir K Roy; Smith, Darrell R; Dobrowsky, Rick T; Fernyhough, Paul

    2011-01-01

    Impairments in mitochondrial function have been proposed to play a role in the etiology of diabetic sensory neuropathy. We tested the hypothesis that mitochondrial dysfunction in axons of sensory neurons in type 1 diabetes is due to abnormal activity of the respiratory chain and an altered mitochondrial proteome. Proteomic analysis using stable isotope labeling with amino acids in cell culture (SILAC) determined expression of proteins in mitochondria from dorsal root ganglia (DRG) of control, 22-week-old streptozotocin (STZ)-diabetic rats, and diabetic rats treated with insulin. Rates of oxygen consumption and complex activities in mitochondria from DRG were measured. Fluorescence imaging of axons of cultured sensory neurons determined the effect of diabetes on mitochondrial polarization status, oxidative stress, and mitochondrial matrix-specific reactive oxygen species (ROS). Proteins associated with mitochondrial dysfunction, oxidative phosphorylation, ubiquinone biosynthesis, and the citric acid cycle were downregulated in diabetic samples. For example, cytochrome c oxidase subunit IV (COX IV; a complex IV protein) and NADH dehydrogenase Fe-S protein 3 (NDUFS3; a complex I protein) were reduced by 29 and 36% (P neurons exhibited oxidative stress and depolarized mitochondria, an aberrant adaption to oligomycin-induced mitochondrial membrane hyperpolarization, but reduced levels of intramitochondrial superoxide compared with control. Abnormal mitochondrial function correlated with a downregulation of mitochondrial proteins, with components of the respiratory chain targeted in lumbar DRG in diabetes. The reduced activity of the respiratory chain was associated with diminished superoxide generation within the mitochondrial matrix and did not contribute to oxidative stress in axons of diabetic neurons. Alternative pathways involving polyol pathway activity appear to contribute to raised ROS in axons of diabetic neurons under high glucose concentration.

  7. Superoxide dismutases and glutaredoxins have a distinct role in the response of Candida albicans to oxidative stress generated by the chemical compounds menadione and diamide.

    Science.gov (United States)

    Chaves, Guilherme Maranhão; da Silva, Walicyranison Plinio

    2012-12-01

    To cope with oxidative stress, Candida albicans possesses several enzymes involved in a number of biological processes, including superoxide dismutases (Sods) and glutaredoxins (Grxs). The resistance of C. albicans to reactive oxygen species is thought to act as a virulence factor. Genes such as SOD1 and GRX2, which encode for a Sod and Grx, respectively, in C. albicans are widely recognised to be important for pathogenesis. We generated a double mutant, Δgrx2/sod1, for both genes. This strain is very defective in hyphae formation and is susceptible to killing by neutrophils. When exposed to two compounds that generate reactive oxygen species, the double null mutant was susceptible to menadione and resistant to diamide. The reintegration of the SOD1 gene in the null mutant led to recovery in resistance to menadione, whereas reintegration of the GRX2 gene made the null mutant sensitive to diamide. Despite having two different roles in the responses to oxidative stress generated by chemical compounds, GRX2 and SOD1 are important for C. albicans pathogenesis because the double mutant Δgrx2/sod1 was very susceptible to neutrophil killing and was defective in hyphae formation in addition to having a lower virulence in an animal model of systemic infection.

  8. Superoxide dismutases and glutaredoxins have a distinct role in the response of Candida albicans to oxidative stress generated by the chemical compounds menadione and diamide

    Directory of Open Access Journals (Sweden)

    Guilherme Maranhão Chaves

    2012-12-01

    Full Text Available To cope with oxidative stress, Candida albicans possesses several enzymes involved in a number of biological processes, including superoxide dismutases (Sods and glutaredoxins (Grxs. The resistance of C. albicans to reactive oxygen species is thought to act as a virulence factor. Genes such as SOD1 and GRX2, which encode for a Sod and Grx, respectively, in C. albicans are widely recognised to be important for pathogenesis. We generated a double mutant, Δgrx2/sod1, for both genes. This strain is very defective in hyphae formation and is susceptible to killing by neutrophils. When exposed to two compounds that generate reactive oxygen species, the double null mutant was susceptible to menadione and resistant to diamide. The reintegration of the SOD1 gene in the null mutant led to recovery in resistance to menadione, whereas reintegration of the GRX2 gene made the null mutant sensitive to diamide. Despite having two different roles in the responses to oxidative stress generated by chemical compounds, GRX2 and SOD1 are important for C. albicans pathogenesis because the double mutant Δgrx2/sod1 was very susceptible to neutrophil killing and was defective in hyphae formation in addition to having a lower virulence in an animal model of systemic infection.

  9. The cytoplasmic Cu,Zn superoxide dismutase of saccharomyces cerevisiae is required for resistance to freeze-thaw stress. Generation of free radicals during freezing and thawing

    DEFF Research Database (Denmark)

    Park, J I; Grant, C M; Davies, Michael Jonathan

    1998-01-01

    The involvement of oxidative stress in freeze-thaw injury to yeast cells was analyzed using mutants defective in a range of antioxidant functions, including Cu,Zn superoxide dismutase (encoded by SOD1), Mn superoxide dismutase (SOD2), catalase A, catalase T, glutathione reductase, gamma...

  10. Ionizing irradiation induces apoptotic damage of salivary gland acinar cells via NADPH oxidase 1-dependent superoxide generation

    International Nuclear Information System (INIS)

    Tateishi, Yoshihisa; Sasabe, Eri; Ueta, Eisaku; Yamamoto, Tetsuya

    2008-01-01

    Reactive oxygen species (ROS) have important roles in various physiological processes. Recently, several novel homologues of the phagocytic NADPH oxidase have been discovered and this protein family is now designated as the Nox family. We investigated the involvement of Nox family proteins in ionizing irradiation-induced ROS generation and impairment in immortalized salivary gland acinar cells (NS-SV-AC), which are radiosensitive, and immortalized ductal cells (NS-SV-DC), which are radioresistant. Nox1-mRNA was upregulated by γ-ray irradiation in NS-SV-AC, and the ROS level in NS-SV-AC was increased to approximately threefold of the control level after 10 Gy irradiation. The increase of ROS level in NS-SV-AC was suppressed by Nox1-siRNA-transfection. In parallel with the suppression of ROS generation and Nox1-mRNA expression by Nox1-siRNA, ionizing irradiation-induced apoptosis was strongly decreased in Nox1-siRNA-transfected NS-SV-AC. There were no large differences in total SOD or catalase activities between NS-SV-AC and NS-SV-DC although the post-irradiation ROS level in NS-SV-AC was higher than that in NS-SV-DC. In conclusion, these results indicate that Nox1 plays a crucial role in irradiation-induced ROS generation and ROS-associated impairment of salivary gland cells and that Nox1 gene may be targeted for preservation of the salivary gland function from radiation-induced impairment

  11. Novel Fluorometric Method for the Determination of Production Rate and Steady-State Concentration of Photochemically Generated Superoxide Radical in Seawater Using 3',6'-(Diphenylphosphinyl)fluorescein.

    Science.gov (United States)

    Anifowose, Adebanjo Jacob; Takeda, Kazuhiko; Sakugawa, Hiroshi

    2015-12-15

    Superoxide radical (O2(•-)) is an important reactive oxygen species in seawater. Measurements of its production rates and steady-state concentrations generated by photochemical processes have been a Herculean task over the years. In this study, a probe - 3'6'-(diphenylphosphinyl)fluorescein (PF-1) - was used to trap photochemically generated O2(•-) in seawater, thereby yielding fluorescein. The fluorescein produced was measured by an isocratic fluorescence HPLC at excitation/emission wavelengths of 490/513 nm, respectively. The reaction rate constant of PF-1 with O2(•-) (kPF-1) was pH-dependent: (3.2-23.5) × 10(7) M(-1) s(-1) at pHTOT 7.65-8.50. By applying appropriate equations, both the production rate and the steady-state concentration of O2(•-) generated by photochemical reactions in the seawater were quantified. Under the optimized experimental conditions, fluorescein standards (3-50 nM) exhibited linearity in the seawater by HPLC. The photoformation of fluorescein, due to the reaction of PF-1 with the O2(•-) photochemically produced in the seawater, was linear within the 20 min irradiation. The detection limit of the fluorescein photoformation rate was 0.03 pM s(-1), defined as 3σ of the lowest standard fluorescein concentration per 20 min irradiation. Using this value, the yield of fluorescein, and the fraction of O2(•-) that reacted with PF-1 in the seawater, the detection limit of the O2(•-) photoformation rate was 1.78 pM s(-1). Superoxide measurements using the proposed method were relatively unaffected by the potential interfering species in seawater. Application of the proposed method to ten (10) seawater samples from the Seto Inland Sea, Japan, resulted in measured O2(•-) photoformation rates of 3.1-8.5 nM s(-1), with steady-state concentrations ranging (0.06-0.3) × 10(-10) M. The method is simple, requires no technical sample preparation, and can be used to analyze a large number of samples.

  12. Ebselen and congeners inhibit NADPH oxidase 2-dependent superoxide generation by interrupting the binding of regulatory subunits.

    Science.gov (United States)

    Smith, Susan M E; Min, Jaeki; Ganesh, Thota; Diebold, Becky; Kawahara, Tsukasa; Zhu, Yerun; McCoy, James; Sun, Aiming; Snyder, James P; Fu, Haian; Du, Yuhong; Lewis, Iestyn; Lambeth, J David

    2012-06-22

    NADPH oxidases (Nox) are a primary source of reactive oxygen species (ROS), which function in normal physiology and, when overproduced, in pathophysiology. Recent studies using mice deficient in Nox2 identify this isoform as a novel target against Nox2-implicated inflammatory diseases. Nox2 activation depends on the binding of the proline-rich domain of its heterodimeric partner p22phox to p47phox. A high-throughput screen that monitored this interaction via fluorescence polarization identified ebselen and several of its analogs as inhibitors. Medicinal chemistry was performed to explore structure-activity relationships and to optimize potency. Ebselen and analogs potently inhibited Nox1 and Nox2 activity but were less effective against other isoforms. Ebselen also blocked translocation of p47phox to neutrophil membranes. Thus, ebselen and its analogs represent a class of compounds that inhibit ROS generation by interrupting the assembly of Nox2-activating regulatory subunits. Copyright © 2012 Elsevier Ltd. All rights reserved.

  13. Antioxidant Effects of Herbal Tea Leaves from Yacon (Smallanthus sonchifolius) on Multiple Free Radical and Reducing Power Assays, Especially on Different Superoxide Anion Radical Generation Systems.

    Science.gov (United States)

    Sugahara, Shintaro; Ueda, Yuto; Fukuhara, Kumiko; Kamamuta, Yuki; Matsuda, Yasushi; Murata, Tatsuro; Kuroda, Yasuhiro; Kabata, Kiyotaka; Ono, Masateru; Igoshi, Keiji; Yasuda, Shin

    2015-11-01

    Yacon (Smallanthus sonchifolius), a native Andean plant, has been cultivated as a crop and locally used as a traditional folk medicine for the people suffering from diabetes and digestive/renal disorders. However, the medicinal properties of this plant and its processed foods have not been completely established. This study investigates the potent antioxidative effects of herbal tea leaves from yacon in different free radical models and a ferric reducing model. A hot-water extract exhibited the highest yield of total polyphenol and scavenging effect on 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical among four extracts prepared with hot water, methanol, ethanol, and ethylacetate. In addition, a higher reducing power of the hot-water extract was similarly demonstrated among these extracts. Varying concentrations of the hot-water extract resulted in different scavenging activities in four synthetic free radical models: DPPH radical (EC50 28.1 μg/mL), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical (EC50 23.7 μg/mL), galvinoxyl radical (EC50 3.06 μg/mL), and chlorpromazine cation radical (EC50 475 μg/mL). The yacon tea-leaf extract further demonstrated superoxide anion (O2(-)) radical scavenging effects in the phenazine methosulfate-NADH-nitroblue tetrazolium (EC50 64.5 μg/mL) and xanthine oxidase assay systems (EC50 20.7 μg/mL). Subsequently, incubating human neutrophilic cells in the presence of the tea-leaf extract could suppress the cellular O2(-) radical generation (IC50 65.7 μg/mL) in a phorbol 12-myristate 13-acetate-activated cell model. These results support yacon tea leaves may be a good source of natural antioxidants for preventing O2(-) radical-mediated disorders. Yacon has been considered to be a potent alternative food source for patients who require a dietary cure in regional area, while the leaf part has been provided and consumed as an herbal tea in local markets. We demonstrated here potent antioxidative effects of the tea

  14. Resveratrol strongly enhances the retinoic acid-induced superoxide generating activity via up-regulation of gp91-phox gene expression in U937 cells.

    Science.gov (United States)

    Kikuchi, Hidehiko; Mimuro, Hitomi; Kuribayashi, Futoshi

    2018-01-01

    The membrane bound cytochrome b 558 composed of gp91-phox and p22-phox proteins, and cytosolic proteins p40-, p47-and p67-phox are important components of superoxide (O 2 - )-generating system in phagocytes. Here, we describe that resveratrol, a pleiotropic phytochemical belonging to the stilbenoids, dramatically activates the O 2 - -generating system during retinoic acid (RA)-induced differentiation of human monoblastic leukemia U937 cells to macrophage-like cells. When U937 cells were cultured in the presence of RA and resveratrol, the O 2 - -generating activity increased more than 5-fold compared with that in the absence of the latter. Semiquantitative RT-PCR showed that co-treatment with RA and resveratrol strongly enhanced transcription of the gp91-phox compared with those of the RA-treatment only. On the other hand, immunoblot analysis revealed that co-treatment with RA and resveratrol caused remarkable accumulation of protein levels of gp91-phox (to 4-fold), p22-phox (to 5-fold) and p47-phox (to 4-fold) compared with those of the RA-treatment alone. In addition, ChIP assay suggested that resveratrol participates in enhancing the gene expression of gp91-phox via promoting acetylation of Lys-9 residues and Lys-14 residues of histone H3 within chromatin around the promoter regions of the gene. These results suggested that resveratrol strongly enhances the RA-induced O 2 - -generating activity via up-regulation of gp91-phox gene expression in U937 cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Acetaminophen and aspirin inhibit superoxide anion generation and lipid peroxidation, and protect against 1-methyl-4-phenyl pyridinium-induced dopaminergic neurotoxicity in rats.

    Science.gov (United States)

    Maharaj, D S; Saravanan, K S; Maharaj, H; Mohanakumar, K P; Daya, S

    2004-04-01

    We assessed the antioxidant activity of non-narcotic analgesics, acetaminophen and aspirin in rat brain homogenates and neuroprotective effects in vivo in rats intranigrally treated with 1-methyl-4-phenyl pyridinium (MPP+). Both drugs inhibited cyanide-induced superoxide anion generation, as well as lipid peroxidation in rat brain homogenates, the combination of the agents resulting in a potentiation of this effect. Acetaminophen or aspirin when administered alone or in combination, did not alter dopamine (DA) levels in the forebrain or in the striatum. Intranigral infusion of MPP+ in rats caused severe depletion of striatal DA levels in the ipsilateral striatum in rats by the third day. Systemic post-treatment of acetaminophen afforded partial protection, whereas similar treatment of aspirin resulted in complete blockade of MPP+-induced striatal DA depletion. While these findings suggest usefulness of non-narcotic analgesics in neuroprotective therapy in neurodegenerative diseases, aspirin appears to be a potential candidate in prophylactic as well as in adjuvant therapy in Parkinson's disease.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-15

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

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

    International Nuclear Information System (INIS)

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

    2012-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

  19. Acute ethanol intake induces superoxide anion generation and mitogen-activated protein kinase phosphorylation in rat aorta: A role for angiotensin type 1 receptor

    Energy Technology Data Exchange (ETDEWEB)

    Yogi, Alvaro; Callera, Glaucia E. [Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ontario (Canada); Mecawi, André S. [Department of Physiology, Faculty of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP (Brazil); Batalhão, Marcelo E.; Carnio, Evelin C. [Department of General and Specialized Nursing, College of Nursing of Ribeirão Preto, USP, São Paulo (Brazil); Antunes-Rodrigues, José [Department of Physiology, Faculty of Medicine of Ribeirão Preto, University of São Paulo (USP), Ribeirão Preto, SP (Brazil); Queiroz, Regina H. [Department of Clinical, Toxicological and Food Science Analysis, Faculty of Pharmaceutical Sciences, USP, São Paulo (Brazil); Touyz, Rhian M. [Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ontario (Canada); Tirapelli, Carlos R., E-mail: crtirapelli@eerp.usp.br [Department of Psychiatric Nursing and Human Sciences, Laboratory of Pharmacology, College of Nursing of Ribeirão Preto, USP, Ribeirão Preto, SP (Brazil)

    2012-11-01

    Ethanol intake is associated with increase in blood pressure, through unknown mechanisms. We hypothesized that acute ethanol intake enhances vascular oxidative stress and induces vascular dysfunction through renin–angiotensin system (RAS) activation. Ethanol (1 g/kg; p.o. gavage) effects were assessed within 30 min in male Wistar rats. The transient decrease in blood pressure induced by ethanol was not affected by the previous administration of losartan (10 mg/kg; p.o. gavage), a selective AT{sub 1} receptor antagonist. Acute ethanol intake increased plasma renin activity (PRA), angiotensin converting enzyme (ACE) activity, plasma angiotensin I (ANG I) and angiotensin II (ANG II) levels. Ethanol induced systemic and vascular oxidative stress, evidenced by increased plasma thiobarbituric acid-reacting substances (TBARS) levels, NAD(P)H oxidase‐mediated vascular generation of superoxide anion and p47phox translocation (cytosol to membrane). These effects were prevented by losartan. Isolated aortas from ethanol-treated rats displayed increased p38MAPK and SAPK/JNK phosphorylation. Losartan inhibited ethanol-induced increase in the phosphorylation of these kinases. Ethanol intake decreased acetylcholine-induced relaxation and increased phenylephrine-induced contraction in endothelium-intact aortas. Ethanol significantly decreased plasma and aortic nitrate levels. These changes in vascular reactivity and in the end product of endogenous nitric oxide metabolism were not affected by losartan. Our study provides novel evidence that acute ethanol intake stimulates RAS activity and induces vascular oxidative stress and redox-signaling activation through AT{sub 1}-dependent mechanisms. These findings highlight the importance of RAS in acute ethanol-induced oxidative damage. -- Highlights: ► Acute ethanol intake stimulates RAS activity and vascular oxidative stress. ► RAS plays a role in acute ethanol-induced oxidative damage via AT{sub 1} receptor activation.

  20. The Term Processor Generator Kimwitu (Full version)

    NARCIS (Netherlands)

    van Eijk, Peter; Belinfante, Axel; Eertink, Henk; Alblas, H.

    1996-01-01

    The Kimwitu system is a meta-tool that supports the construction of programs (tools) that operate on trees or terms. The system supports open multi-paradigm programming, in that it allows to express each part of an implementation in the most appropriate language. Terms can be implemented in a tool

  1. Long term generation planning in Cyprus

    Energy Technology Data Exchange (ETDEWEB)

    Kellas, A [Electricity Authority of Cyprus, Nicosia (Cyprus)

    1997-09-01

    The Wien Automatic System Planning (WASP) model has been used for carrying out generation expansion planning studies in Cyprus since many years. This paper focuses on the problems encountered in the use of the model and illustrates these problems by means of a case study, specially developed for this purpose. Suggestions for future improvements of the model are also made in this paper. (author). 2 figs, 10 tabs.

  2. Superoxide anion production and superoxide dismutase and catalase activities in Coxiella burnetii.

    OpenAIRE

    Akporiaye, E T; Baca, O G

    1983-01-01

    Coxiella burnetii was examined for superoxide anion (O2-) production and superoxide dismutase and catalase activities. The organism generated O2- at pH 4.5 but not at pH 7.4. The rickettsia displayed superoxide dismutase activity distinguishable from that of the host cell (L-929 mouse fibroblast). Catalase activity was maximal at pH 7.0 and diminished at pH 4.5. These enzymes may account, in part, for the ability of this obligate intracellular parasite to survive within phagocytes.

  3. AutoDipole - Automated generation of dipole subtraction terms

    International Nuclear Information System (INIS)

    Hasegawa, K.; Uwer, P.

    2009-11-01

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for bothmassless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. (orig.)

  4. AutoDipole - Automated generation of dipole subtraction terms

    Energy Technology Data Exchange (ETDEWEB)

    Hasegawa, K.; Uwer, P. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Moch, S. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2009-11-15

    We present an automated generation of the subtraction terms for next-to-leading order QCD calculations in the Catani-Seymour dipole formalism. For a given scattering process with n external particles our Mathematica package generates all dipole terms, allowing for bothmassless and massive dipoles. The numerical evaluation of the subtraction terms proceeds with MadGraph, which provides Fortran code for the necessary scattering amplitudes. Checks of the numerical stability are discussed. (orig.)

  5. Term clouds as surrogates for user generated speech

    NARCIS (Netherlands)

    Tsagkias, M.; Larson, M.; de Rijke, M.; Myaeng, S.-H.; Oard, D.W.; Sebastiani, F.; Chua, T.-S.; Leong, M.-K.

    2008-01-01

    User generated spoken audio remains a challenge for Automatic Speech Recognition (ASR) technology and content-based audio surrogates derived from ASR-transcripts must be error robust. An investigation of the use of term clouds as surrogates for podcasts demonstrates that ASR term clouds closely

  6. Medium-term marginal costs in competitive generation power markets

    International Nuclear Information System (INIS)

    Reneses, J.; Centeno, E.; Barquin, J.

    2004-01-01

    The meaning and significance of medium-term marginal costs for a generation company in a competitive power market in analysed. A methodology to compute and decompose medium-term generation marginal costs in a competitive environment is proposed. The methodology is based on a market equilibrium model. The aim is to provide a useful tool for generation companies so that they can manage their resources in an optimal way, helping them with their operation, decision-making processes, asset valuations or contract assessments. (author)

  7. Models of Superoxide Dismutases

    Energy Technology Data Exchange (ETDEWEB)

    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.

  8. Superoxide dismutase of human platelets

    International Nuclear Information System (INIS)

    Kimura, Akiro; Fujimura, Kingo; Kuramoto, Atsushi

    1979-01-01

    Superoxide dismutase (S.O.D.) is the enzyme to protect from destructive effect of superoxide (O 2 -) produced in many metabolic pathways related to oxygen. The purpose of this study was to investigate the possibility that S.O.D. may play an important role in the platelet function. The cytoplasmic and mitochondrial S.O.D. has been investigated spectrophotometrically and gel electrophoretically in human platelets from eleven patients of chronic myelogenous leukemia (CML) and three patients of primary thrombocythemia (P.Th.). Neither deficiency nor abnormality of cytoplasmic and mitochondrial S.O.D. has been found electrophoretically in any case compared to normal platelets. However, the total activity from three of the CML patients and one of the P.Th. patients were above 3 unit/mg platelet protein (normal subject: 2.11 - 2.70 unit/mg protein), suggesting the possibility either that more O 2 -production occurs in the platelets or that rather little O 2 -production due to much O 2 -deprivation by the increased S.O.D. The S.O.D. activity of human platelets has been also investigated in several conditions, where much O 2 -generation might occur in platelets. Sodium fluoride (2 mM), which increases platelet O 2 -production about 3 fold, had no effect on platelet S.O.D. The aggregated platelets induced by ADP (10 -5 M), epinephrin (50 μg/ml), ristocetin (1.5 mg/ml) or collagen (1 - 20 μg/ml) had no increase of S.O.D. activity compared to that from non aggregated platelets. X-ray irradiation (1,000 - 20,000R) had not induced its activity increase or decrease. These findings indicated the induction of platelet S.O.D. was not brought about under these conditions. (author)

  9. Electrocatalytic analysis of superoxide anion radical using nitrogen-doped graphene supported Prussian Blue as a biomimetic superoxide dismutase

    International Nuclear Information System (INIS)

    Liu, Tingting; Niu, Xiangheng; Shi, Libo; Zhu, Xiang; Zhao, Hongli; Lana, Minbo

    2015-01-01

    Graphical abstract: Prussian Blue (PB) cubes supported on nitrogen-doped graphene sheets (NGS) were synthesized using a simple and scalable method, and the utilization of the PB-NGS hybrid as an efficient superoxide dismutase mimic in the electrochemical sensing of O 2 ·− was demonstrated. - Highlights: • Facile and scalable synthesis of Prussian Blue cubes supported on nitrogen-doped graphene; • Nitrogen-doped graphene supported Prussian Blue as an efficient biomimetic superoxide dismutase for the electrocatalytic sensing of superoxide anion; • Good sensitivity, excellent selectivity and attractive long-term stability for superoxide anion sensing. - Abstract: Considering the double-sided roles of superoxide anion radical, monitoring of its track in living systems is attracting increasing academic and practical interest. Here we synthesized Prussian Blue (PB) cubes that were supported on nitrogen-doped graphene sheets (NGS) using a facile and scalable method, and explored their potential utilization in the electrochemical sensing of superoxide anion. As an efficient superoxide dismutase mimic, direct electron transfer of the prepared PB-NGS hybrid immobilized on a screen-printed gold electrode was harvested in physiological media. With the bifunctional activities, the synthetic mimic could catalyze the dismutation of superoxide anion via the redox cycle of active iron. By capturing the electro-reduction amperometric responses of superoxide anion radical to hydrogen peroxide in the cathodic polarization, highly sensitive determination (a sensitivity of as high as 0.32 μA cm −2 μM −1 ) of the target was achieved, with no interference from common coexisting species including ascorbic acid, dopamine, and uric acid observed. Compared to natural superoxide dismutases, the artificial enzyme mimic exhibited favorable activity stability, indicating its promising applications in the in vivo long-term monitoring of superoxide anion

  10. Short-term forecasting model for aggregated regional hydropower generation

    International Nuclear Information System (INIS)

    Monteiro, Claudio; Ramirez-Rosado, Ignacio J.; Fernandez-Jimenez, L. Alfredo

    2014-01-01

    Highlights: • Original short-term forecasting model for the hourly hydropower generation. • The use of NWP forecasts allows horizons of several days. • New variable to represent the capacity level for generating hydroelectric energy. • The proposed model significantly outperforms the persistence model. - Abstract: This paper presents an original short-term forecasting model of the hourly electric power production for aggregated regional hydropower generation. The inputs of the model are previously recorded values of the aggregated hourly production of hydropower plants and hourly water precipitation forecasts using Numerical Weather Prediction tools, as well as other hourly data (load demand and wind generation). This model is composed of three modules: the first one gives the prediction of the “monthly” hourly power production of the hydropower plants; the second module gives the prediction of hourly power deviation values, which are added to that obtained by the first module to achieve the final forecast of the hourly hydropower generation; the third module allows a periodic adjustment of the prediction of the first module to improve its BIAS error. The model has been applied successfully to the real-life case study of the short-term forecasting of the aggregated hydropower generation in Spain and Portugal (Iberian Peninsula Power System), achieving satisfactory results for the next-day forecasts. The model can be valuable for agents involved in electricity markets and useful for power system operations

  11. Model documentation report: Short-Term Hydroelectric Generation Model

    International Nuclear Information System (INIS)

    1993-08-01

    The purpose of this report is to define the objectives of the Short- Term Hydroelectric Generation Model (STHGM), describe its basic approach, and to provide details on the model structure. This report is intended as a reference document for model analysts, users, and the general public. Documentation of the model is in accordance with the Energy Information Administration's (AYE) legal obligation to provide adequate documentation in support of its models (Public Law 94-385, Section 57.b.2). The STHGM performs a short-term (18 to 27- month) forecast of hydroelectric generation in the United States using an autoregressive integrated moving average (UREMIA) time series model with precipitation as an explanatory variable. The model results are used as input for the short-term Energy Outlook

  12. Foresight of nuclear generation at long term in Mexico

    International Nuclear Information System (INIS)

    Guadarrama L, R.; Sanchez R, O. E.; Martin del Campo M, C.

    2009-10-01

    This paper presents an analysis of the nuclear generation expansion for the period 2008-2030. The main objective is to plan the expansion of electrical generation system at long term taking into account four decision criteria. These are, the total cost of generation, the risk associated whit changes in fuel prices, the diversity of the generation park and polluting emissions of global impact (greenhouse effect gases) and local effects (acid rain and suspended particles). The analyzed expansion plans were developed using a model of uni nodal planning called WASP-IV. The analysis methodology was based on four steps. The first consisted in developing, with model WASP-IV, different expansion plans of the electrical generation system that fulfill the energy demand and certain conditions of the study in which was optimized the additions program of generator units searching the minimal cost of electrical generation. The second step was to calculate the generation costs of each plan for two scenarios of fuel prices, also with model WASP-IV. Later was calculated the diversity index and the accumulated emissions during the expansion and the avoided emission of CO 2 when units of combined cycle that burn natural gas are replaced by nuclear power units. (Author)

  13. Role of the NAD(P)H quinone oxidoreductase NQR and the cytochrome b AIR12 in controlling superoxide generation at the plasma membrane.

    Science.gov (United States)

    Biniek, Catherine; Heyno, Eiri; Kruk, Jerzy; Sparla, Francesca; Trost, Paolo; Krieger-Liszkay, Anja

    2017-04-01

    The quinone reductase NQR and the b-type cytochrome AIR12 of the plasma membrane are important for the control of reactive oxygen species in the apoplast. AIR12 and NQR are two proteins attached to the plant plasma membrane which may be important for generating and controlling levels of reactive oxygen species in the apoplast. AIR12 (Auxin Induced in Root culture) is a single gene of Arabidopsis that codes for a mono-heme cytochrome b. The NADPH quinone oxidoreductase NQR is a two-electron-transferring flavoenzyme that contributes to the generation of O 2 •- in isolated plasma membranes. A. thaliana double knockout plants of both NQR and AIR12 generated more O 2 •- and germinated faster than the single mutant affected in AIR12. To test whether NQR and AIR12 are able to interact functionally, recombinant purified proteins were added to plasma membranes isolated from soybean hypocotyls. In vitro NADH-dependent O 2 •- production at the plasma membrane in the presence of NQR was reduced upon addition of AIR12. Electron donation from semi-reduced menadione to AIR12 was shown to take place. Biochemical analysis showed that purified plasma membrane from soybean hypocotyls or roots contained phylloquinone and menaquinone-4 as redox carriers. This is the first report on the occurrence of menaquinone-4 in eukaryotic photosynthetic organisms. We propose that NQR and AIR12 interact via the quinone, allowing an electron transfer from cytosolic NAD(P)H to apoplastic monodehydroascorbate and control thereby the level of reactive oxygen production and the redox state of the apoplast.

  14. Superoxide dismutase: an industrial perspective.

    Science.gov (United States)

    Bafana, Amit; Dutt, Som; Kumar, Sanjay; Ahuja, Paramvir S

    2011-03-01

    The application of enzyme technologies to industrial research, development, and manufacturing has become a very important field. Since the production of crude rennet in 1874, several enzymes have been commercialized, and used for therapeutic, supplementary, and other applications. Recent advancements in biotechnology now allow companies to produce safer and less expensive enzymes with enhanced potency and specificity. Antioxidant enzymes are emerging as a new addition to the pool of industrial enzymes and are surpassing all other enzymes in terms of the volume of research and production. In the 1990s, an antioxidant enzyme--superoxide dismutase (SOD)--was introduced into the market. Although the enzyme initially showed great promise in therapeutic applications, it did not perform up to expectations. Consequently, its use was limited to non-drug applications in humans and drug applications in animals. This review summarizes the rise and fall of SOD at the industrial level, the reasons for this, and potential future thrust areas that need to be addressed. The review also focuses on other industrially relevant aspects of SOD such as industrial importance, enzyme engineering, production processes, and process optimization and scale-up.

  15. Long term reliability analysis of standby diesel generators

    International Nuclear Information System (INIS)

    Winfield, D.J.

    1988-01-01

    The long term reliability of 11 diesel generators of 125 to 250 kV A size has been analysed from 26 years of data base information on individual diesel service as standby power supplies for the Chalk River research reactor facilities. Failure to start on demand and failure to run data is presented and failure by diesel subsystem and multiple failures are also analysed. A brief comparison is made with reliability studies of larger diesel generator units used for standby power service in nuclear power plants. (author)

  16. Lifting Term Rewriting Derivations in Constructor Systems by Using Generators

    Directory of Open Access Journals (Sweden)

    Adrián Riesco

    2015-01-01

    Full Text Available Narrowing is a procedure that was first studied in the context of equational E-unification and that has been used in a wide range of applications. The classic completeness result due to Hullot states that any term rewriting derivation starting from an instance of an expression can be "lifted" to a narrowing derivation, whenever the substitution employed is normalized. In this paper we adapt the generator- based extra-variables-elimination transformation used in functional-logic programming to overcome that limitation, so we are able to lift term rewriting derivations starting from arbitrary instances of expressions. The proposed technique is limited to left-linear constructor systems and to derivations reaching a ground expression. We also present a Maude-based implementation of the technique, using natural rewriting for the on-demand evaluation strategy.

  17. Efficiency of superoxide anions in the inactivation of selected dehydrogenases

    International Nuclear Information System (INIS)

    Rodacka, Aleksandra; Serafin, Eligiusz; Puchala, Mieczyslaw

    2010-01-01

    The most ubiquitous of the primary reactive oxygen species, formed in all aerobes, is the superoxide free radical. It is believed that the superoxide anion radical shows low reactivity and in oxidative stress it is regarded mainly as an initiator of more reactive species such as · OH and ONOO - . In this paper, the effectiveness of inactivation of selected enzymes by radiation-generated superoxide radicals in comparison with the effectiveness of the other products of water radiolysis is examined. We investigate three enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH). We show that the direct contribution of the superoxide anion radical to GAPDH and ADH inactivation is significant. The effectiveness of the superoxide anion in the inactivation of GAPDH and ADG was only 2.4 and 2.8 times smaller, respectively, in comparison with hydroxyl radical. LDH was practically not inactivated by the superoxide anion. Despite the fact that the studied dehydrogenases belong to the same class of enzymes (oxidoreductases), all have a similar molecular weight and are tetramers, their susceptibility to free-radical damage varies. The differences in the radiosensitivity of the enzymes are not determined by the basic structural parameters analyzed. A significant role in inactivation susceptibility is played by the type of amino acid residues and their localization within enzyme molecules.

  18. Efficiency of superoxide anions in the inactivation of selected dehydrogenases

    Energy Technology Data Exchange (ETDEWEB)

    Rodacka, Aleksandra, E-mail: olakow@biol.uni.lodz.p [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland); Serafin, Eligiusz, E-mail: serafin@biol.uni.lodz.p [Laboratory of Computer and Analytical Techniques, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland); Puchala, Mieczyslaw, E-mail: puchala@biol.uni.lodz.p [Department of Molecular Biophysics, University of Lodz, Banacha 12/16, 90-237 Lodz (Poland)

    2010-09-15

    The most ubiquitous of the primary reactive oxygen species, formed in all aerobes, is the superoxide free radical. It is believed that the superoxide anion radical shows low reactivity and in oxidative stress it is regarded mainly as an initiator of more reactive species such as {sup {center_dot}}OH and ONOO{sup -}. In this paper, the effectiveness of inactivation of selected enzymes by radiation-generated superoxide radicals in comparison with the effectiveness of the other products of water radiolysis is examined. We investigate three enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH). We show that the direct contribution of the superoxide anion radical to GAPDH and ADH inactivation is significant. The effectiveness of the superoxide anion in the inactivation of GAPDH and ADG was only 2.4 and 2.8 times smaller, respectively, in comparison with hydroxyl radical. LDH was practically not inactivated by the superoxide anion. Despite the fact that the studied dehydrogenases belong to the same class of enzymes (oxidoreductases), all have a similar molecular weight and are tetramers, their susceptibility to free-radical damage varies. The differences in the radiosensitivity of the enzymes are not determined by the basic structural parameters analyzed. A significant role in inactivation susceptibility is played by the type of amino acid residues and their localization within enzyme molecules.

  19. Short-term generation scheduling model of Fujian hydro system

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jinwen [School of Hydropower and Information Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)], E-mail: dr.jinwen.wang@gmail.com

    2009-04-15

    The Fujian hydropower system (FHS) is one of the provincial hydropower systems with the most complicated hydraulic topology in China. This paper describes an optimization program that is required by Fujian Electric Power Company Ltd. (FEPCL) to aid the shift engineers in making decisions with the short-term hydropower scheduling such that the generation benefit can be maximal. The problem involves 27 reservoirs and is formulated as a nonlinear and discrete programming. It is a very challenging task to solve such a large-scale problem. In this paper, the Lagrangian multipliers are introduced to decompose the primal problem into a hydro subproblem and many individual plant-based subproblems, which are respectively solved by the improved simplex-like method (SLM) and the dynamic programming (DP). A numerical example is given and the derived solution is very close to the optimal one, with the distance in benefit less than 0.004%. All the data needed for the numerical example are presented in detail for further tests and studies from more experts and researchers.

  20. Short-term generation scheduling model of Fujian hydro system

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jinwen [School of Hydropower and Information Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2009-04-15

    The Fujian hydropower system (FHS) is one of the provincial hydropower systems with the most complicated hydraulic topology in China. This paper describes an optimization program that is required by Fujian Electric Power Company Ltd. (FEPCL) to aid the shift engineers in making decisions with the short-term hydropower scheduling such that the generation benefit can be maximal. The problem involves 27 reservoirs and is formulated as a nonlinear and discrete programming. It is a very challenging task to solve such a large-scale problem. In this paper, the Lagrangian multipliers are introduced to decompose the primal problem into a hydro subproblem and many individual plant-based subproblems, which are respectively solved by the improved simplex-like method (SLM) and the dynamic programming (DP). A numerical example is given and the derived solution is very close to the optimal one, with the distance in benefit less than 0.004%. All the data needed for the numerical example are presented in detail for further tests and studies from more experts and researchers. (author)

  1. The influence of extracellular superoxide on iron redox chemistry and bioavailability to aquatic microorganisms

    Directory of Open Access Journals (Sweden)

    Andrew eRose

    2012-04-01

    Full Text Available Superoxide, the one-electron reduced form of dioxygen, is produced in the extracellular milieu of aquatic microbes through a range of abiotic chemical processes and also by microbes themselves. Due to its ability to promote both oxidative and reductive reactions, superoxide may have a profound impact on the redox state of iron, potentially influencing iron solubility, complex speciation and bioavailability. The interplay between iron, superoxide and oxygen may also produce a cascade of other highly reactive transients in oxygenated natural waters. For microbes, the overall effect of reactions between superoxide and iron may be deleterious or beneficial, depending on the organism and its chemical environment. Here I critically discuss recent advances in understanding: (i sources of extracellular superoxide in natural waters, with a particular emphasis on microbial generation; (ii the chemistry of reactions between superoxide and iron; and (iii the influence of these processes on iron bioavailability and microbial iron nutrition.

  2. Requirements for superoxide-dependent tyrosine hydroperoxide formation in peptides

    DEFF Research Database (Denmark)

    Winterbourn, Christine C; Parsons-Mair, Helena N; Gebicki, Silvia

    2004-01-01

    Superoxide reacts rapidly with other radicals, but these reactions have received little attention in the context of oxidative stress. For tyrosyl radicals, reaction with superoxide is 3-fold faster than dimerization, and forms the addition product tyrosine hydroperoxide. We have explored structural...... requirements for hydroperoxide formation using tyrosine analogues and di- and tri-peptides. Superoxide and phenoxyl radicals were generated using xanthine oxidase, peroxidase and the respective tyrosine derivative, or by gamma-radiation. Peroxides were measured using FeSO4/Xylenol Orange. Tyrosine and tyramine...... formed stable hydroperoxides, but N-acetyltyrosine and p-hydroxyphenylacetic acid did not, demonstrating a requirement for a free amino group. Using [14C]tyrosine, the hydroperoxide and dityrosine were formed at a molar ratio of 1.8:1. Studies with pre-formed hydroperoxides, and measurements of substrate...

  3. Constraints on superoxide mediated formation of manganese oxides

    Directory of Open Access Journals (Sweden)

    Deric R. Learman

    2013-09-01

    Full Text Available 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, 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.

  4. Long-term need for new generating capacity

    International Nuclear Information System (INIS)

    Bloomster, C.H.; Merrill, E.T.

    1987-03-01

    Electricity demand should continue to grow at about the same rate as GNP, creating a need for large amounts of new generating capacity by the year 2000. Only coal and nuclear at this time have the abundant domestic resources and assured technology to meet this need. However, large increase in both coal and nuclear usage will not be acceptable to society without solutions to many of the problems that now deter their increased usage. For coal, the problems center around the safety and environmental impacts of increased coal mining and coal combustion. For nuclear the problems center around reactor safety, radioactive waste disposal, financial risk, and nuclear materials safeguards. The fuel requirements and waste generation for coal plants are orders of magnitude greater than for nuclear. Technology improvements and waste management practices must be pursued to mitigate environmental and safety impacts from electricity generation. 26 refs., 14 figs., 23 tabs

  5. Moduli stabilization and uplifting with dynamically generated F-terms

    International Nuclear Information System (INIS)

    Dudas, Emilian; Papineau, Chloe; Pokorski, Stefan

    2007-01-01

    We use the F-term dynamical supersymmetry breaking models with metastable vacua in order to uplift the vacuum energy in the KKLT moduli stabilization scenario. The main advantage compared to earlier proposals is the manifest supersymmetric treatment and the natural coexistence of a TeV gravitino mass with a zero cosmological constant. We argue that it is generically difficult to avoid anti de-Sitter supersymmetric minima, however the tunneling rate from the metastable vacuum with zero vacuum energy towards them can be very suppressed. We briefly comment on the properties of the induced soft terms in the observable sector

  6. Moduli stabilization and uplifting with dynamically generated F-terms

    Energy Technology Data Exchange (ETDEWEB)

    Dudas, Emilian [CERN Theory Division, CH-1211, Geneva 23 (Switzerland); Papineau, Chloe [CPhT, Ecole Polytechnique, F-91128 Palaiseau Cedex (France); Pokorski, Stefan [Institute of Theoretical Physics, Univ. of Warsaw, 00-681 Warsaw (Poland)

    2007-02-15

    We use the F-term dynamical supersymmetry breaking models with metastable vacua in order to uplift the vacuum energy in the KKLT moduli stabilization scenario. The main advantage compared to earlier proposals is the manifest supersymmetric treatment and the natural coexistence of a TeV gravitino mass with a zero cosmological constant. We argue that it is generically difficult to avoid anti de-Sitter supersymmetric minima, however the tunneling rate from the metastable vacuum with zero vacuum energy towards them can be very suppressed. We briefly comment on the properties of the induced soft terms in the observable sector.

  7. Superoxide dismutases in chronic gastritis.

    Science.gov (United States)

    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. © 2016 APMIS. Published by John Wiley & Sons Ltd.

  8. Role of nitric oxide and superoxide in Giardia lamblia killing

    Directory of Open Access Journals (Sweden)

    P.D. Fernandes

    1997-01-01

    Full Text Available Giardia lamblia trophozoites were incubated for 2 h with activated murine macrophages, nitric oxide (NO donors or a superoxide anion generator (20 mU/ml xanthine oxidase plus 1 mM xanthine. Activated macrophages were cytotoxic to Giardia trophozoites (~60% dead trophozoites. This effect was inhibited (>90% by an NO synthase inhibitor (200 µM and unaffected by superoxide dismutase (SOD, 300 U/ml. Giardia trophozoites were killed by the NO donors, S-nitroso-acetyl-penicillamine (SNAP and sodium nitroprusside (SNP in a dose-dependent manner (LD50 300 and 50 µM, respectively. A dual NO-superoxide anion donor, 3-morpholino-sydnonimine hydrochloride (SIN-1, did not have a killing effect in concentrations up to 1 mM. However, when SOD (300 U/ml was added simultaneously with SIN-1 to Giardia, a significant trophozoite-killing effect was observed (~35% dead trophozoites at 1 mM. The mixture of SNAP or SNP with superoxide anion, which yields peroxynitrite, abolished the trophozoite killing induced by NO donors. Authentic peroxynitrite only killed trophozoites at very high concentrations (3 mM. These results indicate that NO accounts for Giardia trophozoite killing and this effect is not mediated by peroxynitrite

  9. Formation and disappearance of superoxide radicals in aqueous solutions

    International Nuclear Information System (INIS)

    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 2 /HO 2 - by radiolysis and photolysis, electrolysis, mixing nonaqueous solutions into water, chemical reactions, enzymatic generation of O 2 - , and photosensitization; and properties of HO 2 /O 2 - in aqueous solution, which cover spontaneous dismutation rates, pk and absorption spectra, catalyzed dismutation, thermodynamics and the so-called Haber-Weiss Reaction

  10. Developing a high performance superoxide dismutase based electrochemical biosensor for radiation dosimetry of thallium 201

    International Nuclear Information System (INIS)

    Salem, Fatemeh; Tavakoli, Hassan; Sadeghi, Mahdi; Riazi, Abbas

    2014-01-01

    To develop a new biosensor for measurement of superoxide free radical generated in radiolysis reaction, three combinations of SOD-based biosensors including Au/Cys/SOD, Au/GNP/Cys/SOD and Au/GNP/Cys/SOD/Chit were fabricated. In these biosensors Au, GNP, Cys, SOD and Chit represent gold electrode, gold nano-particles, cysteine, superoxide dismutase and chitosan, respectively. For biosensors fabrication, SOD, GNP, Cys and Chit were immobilized at the surface of gold electrode. Cyclic voltametry and chronoamperometry were utilized for evaluation of biosensors performances. The results showed that Au/GNP/Cys/SOD/Chit has significantly better responses compared to Au/Cys/SOD and Au/GNP/Cys/SOD. As a result, this biosensor was selected for dosimetry of ionizing radiation. For this purpose, thallium 201 at different volumes was added to buffer phosphate solution in electrochemical cell. To obtain analytical parameters of Au/GNP/Cys/SOD/Chit, calibration curve was sketched. The results showed that this biosensor has a linear response in the range from 0.5 to 4 Gy, detection limit 0.03 μM. It also has a proper sensitivity (0.6038 nA/Gy), suitable long term stability and cost effective as well as high function for radiation dosimetry. - highlights: • Our biosensor is able to measure produced superoxide radical during water radiolysis. • It has suitable linearity range, good detection limit and long term stability. • It also has proper sensitivity and high performance for low LET ionizing radiation. • The electrochemical method is as good as traditional methods for radiation dosimetry

  11. Experimental study of antiradiation properties of recombinant superoxide dismutase

    International Nuclear Information System (INIS)

    Derimedvyid', L.V.; Simonova, L.Yi.; Gertman, V.Z.

    2003-01-01

    The study involved 250 mongrel white male mice weighing 18-22 g. It was shown that the superoxide dismutase had a marked radioprotective effect. The experiments on animals exposed to ionizing radiation at a absolute and mean lethal doses demonstrate considerable increase of survival rate, mean life span of the dead animals, shifts in the peaks of lethality to later terms, reduction in the percentage of animals with intestinal syndrome,

  12. The Role of Superoxide Dismutase in Inducing of Wheat Seedlings Tolerance to Osmotic Shock

    Directory of Open Access Journals (Sweden)

    Oboznyi A.I.

    2013-08-01

    Full Text Available Influence of short-term hardening osmotic exposure (immersion in 1 M sucrose solution with subsequent transferring to distilled water for 20 min on the hydrogen peroxide generation and superoxide dismutase activity in wheat (Triticum aestivum L., cv. Elegiya seedlings and their tolerance to osmotic shock were investigated. During the initial 30 min after osmotic exposure, the increasing of hydrogen peroxide amount in roots and shoots (to a lesser extent was observed, but the resistance of the seedlings and superoxide dismutase (SOD activity decreased. Sometime later the decrease in hydrogen peroxide amount and the increase of seedlings tolerance to osmotic shock took place. SOD activity increased in 10 min after hardening osmotic exposure. Transient accumulation of hydrogen peroxide induced in this way was suppressed by the treatment of seedlings with sodium diethyldithiocarbamate (DDC, SOD inhibitor. DDC and hydrogen peroxide scavenger dimethylthiourea decreased positive hardening effect of osmotic exposure on the development of seedlings tolerance. It was concluded that SOD providing the generation of signal hydrogen peroxide pool took part in the induction of seedlings tolerance to osmotic shock development caused by preliminary hardening effect.

  13. Biological Superoxide In Manganese Oxide Formation

    Science.gov (United States)

    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.

  14. Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

    International Nuclear Information System (INIS)

    Yoshinaka, Taeko; Yano, Keiji; Yamaguchi, Hikoyuki

    1976-01-01

    The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showed relatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells. (Kako, I.)

  15. Cell lysis and superoxide dismutase activities of highly radioresistant bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinaka, T; Yano, K; Yamaguchi, H [Tokyo Univ. (Japan). Faculty of Agriculture

    1976-01-01

    The highly radioresistant bacterium, Arthrobacter radiotolerans, has been isolated from the radioactive hot spring of Misasa, and it does not sporulate, it is Gram-positive, and its color is pink to red. This bacterium shows the highest resistance to gamma-ray among Gram-positive resistants, but the lytic enzyme capable of lysing the cells of strong radioresistants and the surface structure of the cells are little known except those about Micrococcus radiodurans. The cells of the M. radiodurans can be lysed by Achramobacter lyticus enzyme, and electron microscopic observation and chemical analysis revealed the mutilayered surface structure of the cells consisting of an inner membrane, a mucopeptide wall layer and a very outer layer. The superoxide dismutase (SOD) activity of aerobic and anaerobic bacteria was studied, and the relatively high SOD activity of the M. radiodurans was found. The SOD function acts against the threat posed by the reactive superoxide radical being generated biologically, photochemically and radiochemically in the presence of molecular oxygen. In this paper, it is reported that the lytic enzyme No.2 obtained from Cytophaga sp., containing N-acetyl-muramyl-L-alanine amidase, peptidase and endopeptidase, and showing broad lytic spectra, was able to lyse the cells of A. radiotolerans and four radioresistant micrococci, and the radioresistant bacteria showedrelatively high SOD activity except M. sp. 248. It is well known that superoxide anions are generated by aerobic irradiation, and are toxic to microbial cells.

  16. ACTIVITY OF SUPEROXIDE DISMUTASE ENZYME IN YEAST SACCHAROMYCES CEREVISIAE

    Directory of Open Access Journals (Sweden)

    Blažena Lavová

    2014-02-01

    Full Text Available Reactive oxygen species (ROS with reactive nitrogen species (RNS are known to play dual role in biological systems, they can be harmful or beneficial to living systems. ROS can be important mediators of damage to cell structures, including proteins, lipids and nucleic acids termed as oxidative stress. The antioxidant enzymes protect the organism against the oxidative damage caused by active oxygen forms. The role of superoxide dismutase (SOD is to accelerate the dismutation of the toxic superoxide radical, produced during oxidative energy processes, to hydrogen peroxide and molecular oxygen. In this study, SOD activity of three yeast strains Saccharomyces cerevisiae was determined. It was found that SOD activity was the highest (23.7 U.mg-1 protein in strain 612 after 28 hours of cultivation. The lowest SOD activity from all tested strains was found after 56 hours of cultivation of strain Gyöng (0.7 U.mg-1 protein.

  17. Radiative generation of the CPT-even gauge term of the SME from a dimension-five nonminimal coupling term

    Energy Technology Data Exchange (ETDEWEB)

    Casana, R., E-mail: rodolfo.casana@gmail.com [Universidade Federal do Maranhão (UFMA), Departamento de Física, Campus Universitário do Bacanga, São Luís, MA, 65085-580 (Brazil); Ferreira, M.M., E-mail: manojr07@ibest.com.br [Universidade Federal do Maranhão (UFMA), Departamento de Física, Campus Universitário do Bacanga, São Luís, MA, 65085-580 (Brazil); Maluf, R.V., E-mail: robertovinhaes@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Fortaleza, CE, C.P. 6030, 60455-760 (Brazil); Santos, F.E.P. dos, E-mail: fredegol@ibest.com.br [Universidade Federal do Maranhão (UFMA), Departamento de Física, Campus Universitário do Bacanga, São Luís, MA, 65085-580 (Brazil)

    2013-11-04

    In this Letter we show for the first time that the usual CPT-even gauge term of the Standard Model Extension (SME), in its full structure, can be radiatively generated, in a gauge invariant level, in the context of a modified QED endowed with a dimension-five nonminimal coupling term recently proposed in the literature. As a consequence, the existing upper bounds on the coefficients of the tensor (K{sub F}) can be used to improve the bounds on the magnitude of the nonminimal coupling, λ(K{sub σF}), by the factors 10{sup 5} or 10{sup 25}. The nonminimal coupling also generates higher-order derivative contributions to the gauge field effective action quadratic terms.

  18. Superoxide radicals can act synergistically with hypochlorite to induce damage to proteins

    DEFF Research Database (Denmark)

    Hawkins, Clare Louise; Rees, Martin D; Davies, Michael Jonathan

    2002-01-01

    Activated phagocytes generate both superoxide radicals via a respiratory burst, and HOCl via the concurrent release of the haem enzyme myeloperoxidase. Amine and amide functions on proteins and carbohydrates are major targets for HOCl, generating chloramines (RNHCl) and chloramides (RC(O)NClR'), ......Activated phagocytes generate both superoxide radicals via a respiratory burst, and HOCl via the concurrent release of the haem enzyme myeloperoxidase. Amine and amide functions on proteins and carbohydrates are major targets for HOCl, generating chloramines (RNHCl) and chloramides (RC...

  19. Ontorat: automatic generation of new ontology terms, annotations, and axioms based on ontology design patterns.

    Science.gov (United States)

    Xiang, Zuoshuang; Zheng, Jie; Lin, Yu; He, Yongqun

    2015-01-01

    It is time-consuming to build an ontology with many terms and axioms. Thus it is desired to automate the process of ontology development. Ontology Design Patterns (ODPs) provide a reusable solution to solve a recurrent modeling problem in the context of ontology engineering. Because ontology terms often follow specific ODPs, the Ontology for Biomedical Investigations (OBI) developers proposed a Quick Term Templates (QTTs) process targeted at generating new ontology classes following the same pattern, using term templates in a spreadsheet format. Inspired by the ODPs and QTTs, the Ontorat web application is developed to automatically generate new ontology terms, annotations of terms, and logical axioms based on a specific ODP(s). The inputs of an Ontorat execution include axiom expression settings, an input data file, ID generation settings, and a target ontology (optional). The axiom expression settings can be saved as a predesigned Ontorat setting format text file for reuse. The input data file is generated based on a template file created by a specific ODP (text or Excel format). Ontorat is an efficient tool for ontology expansion. Different use cases are described. For example, Ontorat was applied to automatically generate over 1,000 Japan RIKEN cell line cell terms with both logical axioms and rich annotation axioms in the Cell Line Ontology (CLO). Approximately 800 licensed animal vaccines were represented and annotated in the Vaccine Ontology (VO) by Ontorat. The OBI team used Ontorat to add assay and device terms required by ENCODE project. Ontorat was also used to add missing annotations to all existing Biobank specific terms in the Biobank Ontology. A collection of ODPs and templates with examples are provided on the Ontorat website and can be reused to facilitate ontology development. With ever increasing ontology development and applications, Ontorat provides a timely platform for generating and annotating a large number of ontology terms by following

  20. Development of source term evaluation method for Korean Next Generation Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Keon Jae; Cheong, Jae Hak; Park, Jin Baek; Kim, Guk Gee [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-10-15

    This project had investigate several design features of radioactive waste processing system and method to predict nuclide concentration at primary coolant basic concept of next generation reactor and safety goals at the former phase. In this project several prediction methods of source term are evaluated conglomerately and detailed contents of this project are : model evaluation of nuclide concentration at Reactor Coolant System, evaluation of primary and secondary coolant concentration of reference Nuclear Power Plant(NPP), investigation of prediction parameter of source term evaluation, basic parameter of PWR, operational parameter, respectively, radionuclide removal system and adjustment values of reference NPP, suggestion of source term prediction method of next generation NPP.

  1. Functional analysis of H2O2-generating systems in Botrytis cinerea: the major Cu-Zn-superoxide dismutase (BCSOD1) contributes to virulence on French bean, whereas a glucose oxidase (BCGOD1) is dispensable

    NARCIS (Netherlands)

    Rolke, Y.; Liu, S.; Quidde, T.; Williamson, B.; Schouten, A.; Weltring, K.M.; Siewers, V.; Tenberge, K.B.; Tudzynski, B.; Tudzynski, P.

    2004-01-01

    The oxidative burst, a transient and rapid accumulation of reactive oxygen species (ROS), is a widespread defence mechanism of higher plants against pathogen attack. There is increasing evidence that the necrotrophic fungal pathogen Botrytis cinerea itself generates ROS, and that this capability

  2. Lorentz-violating Yang-Mills theory. Discussing the Chern-Simons-like term generation

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Tiago R.S.; Sobreiro, Rodrigo F. [UFF-Universidade Federal Fluminense, Instituto de Fisica, Niteroi, RJ (Brazil)

    2017-12-15

    We analyze the Chern-Simons-like term generation in the CPT-odd Lorentz-violating Yang-Mills theory interacting with fermions. Moreover, we study the anomalies of this model as well as its quantum stability. The whole analysis is performed within the algebraic renormalization theory, which is independent of the renormalization scheme. In addition, all results are valid to all orders in perturbation theory. We find that the Chern-Simons-like term is not generated by radiative corrections, just like its Abelian version. Additionally, the model is also free of gauge anomalies and quantum stable. (orig.)

  3. Superoxide production and expression of NAD(P)H oxidases by transformed and primary human colonic epithelial cells

    DEFF Research Database (Denmark)

    Perner, A; Andresen, Lars; Pedersen, G

    2003-01-01

    Superoxide (O(2)(-)) generation through the activity of reduced nicotinamide dinucleotide (NADH) or reduced nicotinamide dinucleotide phosphate (NADPH) oxidases has been demonstrated in a variety of cell types, but not in human colonic epithelial cells....

  4. Differential Effects of Superoxide Dismutase Mimetics after Mechanical Overload of Articular Cartilage

    Directory of Open Access Journals (Sweden)

    Mitchell C. Coleman

    2017-11-01

    Full Text Available Post-traumatic osteoarthritis can develop as a result of the initial mechanical impact causing the injury and also as a result of chronic changes in mechanical loading of the joint. Aberrant mechanical loading initiates excessive production of reactive oxygen species, oxidative damage, and stress that appears to damage mitochondria in the surviving chondrocytes. To probe the benefits of increasing superoxide removal with small molecular weight superoxide dismutase mimetics under severe loads, we applied both impact and overload injury scenarios to bovine osteochondral explants using characterized mechanical platforms with and without GC4403, MnTE-2-PyP, and MnTnBuOE-2-PyP. In impact scenarios, each of these mimetics provides some dose-dependent protection from cell death and loss of mitochondrial content while in repeated overloading scenarios only MnTnBuOE-2-PyP provided a clear benefit to chondrocytes. These results support the hypothesis that superoxide is generated in excess after impact injuries and suggest that superoxide production within the lipid compartment may be a critical mediator of responses to chronic overload. This is an important nuance distinguishing roles of superoxide, and thus superoxide dismutases, in mediating damage to cellular machinery in hyper-acute impact scenarios compared to chronic scenarios.

  5. Generation of statistical scenarios of short-term wind power production

    DEFF Research Database (Denmark)

    Pinson, Pierre; Papaefthymiou, George; Klockl, Bernd

    2007-01-01

    Short-term (up to 2-3 days ahead) probabilistic forecasts of wind power provide forecast users with a paramount information on the uncertainty of expected wind generation. Whatever the type of these probabilistic forecasts, they are produced on a per horizon basis, and hence do not inform...... on the development of the forecast uncertainty through forecast series. This issue is addressed here by describing a method that permits to generate statistical scenarios of wind generation that accounts for the interdependence structure of prediction errors, in plus of respecting predictive distributions of wind...

  6. Spot markets vs. long-term contracts - modelling tools for regional electricity generating utilities

    International Nuclear Information System (INIS)

    Grohnheit, P.E.

    1999-01-01

    A properly organised market for electricity requires that some information will be available for all market participants. Also a range of generally available modelling tools are necessary. This paper describes a set of simple models based on published data for analyses of the long-term revenues of regional utilities with combined heat and power generation (CHP), who will operate a competitive international electricity market and a local heat market. The future revenues from trade on the spot market is analysed using a load curve model, in which marginal costs are calculated on the basis of short-term costs of the available units and chronological hourly variations in the demands for electricity and heat. Assumptions on prices, marginal costs and electricity generation by the different types of generating units are studied for selected types of local electricity generators. The long-term revenue requirements to be met by long-term contracts are analysed using a traditional techno-economic optimisation model focusing on technology choice and competition among technologies over 20.30 years. A possible conclusion from this discussion is that it is important for the economic and environmental efficiency of the electricity market that local or regional generators of CHP, who are able to react on price signals, do not conclude long-term contracts that include fixed time-of-day tariff for sale of electricity. Optimisation results for a CHP region (represented by the structure of the Danish electricity and CHP market in 1995) also indicates that a market for CO 2 tradable permits is unlikely to attract major non-fossil fuel technologies for electricity generation, e.g. wind power. (au)

  7. Very Short-term Nonparametric Probabilistic Forecasting of Renewable Energy Generation - with Application to Solar Energy

    DEFF Research Database (Denmark)

    Golestaneh, Faranak; Pinson, Pierre; Gooi, Hoay Beng

    2016-01-01

    Due to the inherent uncertainty involved in renewable energy forecasting, uncertainty quantification is a key input to maintain acceptable levels of reliability and profitability in power system operation. A proposal is formulated and evaluated here for the case of solar power generation, when only...... approach to generate very short-term predictive densities, i.e., for lead times between a few minutes to one hour ahead, with fast frequency updates. We rely on an Extreme Learning Machine (ELM) as a fast regression model, trained in varied ways to obtain both point and quantile forecasts of solar power...... generation. Four probabilistic methods are implemented as benchmarks. Rival approaches are evaluated based on a number of test cases for two solar power generation sites in different climatic regions, allowing us to show that our approach results in generation of skilful and reliable probabilistic forecasts...

  8. TermGenie - a web-application for pattern-based ontology class generation.

    Science.gov (United States)

    Dietze, Heiko; Berardini, Tanya Z; Foulger, Rebecca E; Hill, David P; Lomax, Jane; Osumi-Sutherland, David; Roncaglia, Paola; Mungall, Christopher J

    2014-01-01

    Biological ontologies are continually growing and improving from requests for new classes (terms) by biocurators. These ontology requests can frequently create bottlenecks in the biocuration process, as ontology developers struggle to keep up, while manually processing these requests and create classes. TermGenie allows biocurators to generate new classes based on formally specified design patterns or templates. The system is web-based and can be accessed by any authorized curator through a web browser. Automated rules and reasoning engines are used to ensure validity, uniqueness and relationship to pre-existing classes. In the last 4 years the Gene Ontology TermGenie generated 4715 new classes, about 51.4% of all new classes created. The immediate generation of permanent identifiers proved not to be an issue with only 70 (1.4%) obsoleted classes. TermGenie is a web-based class-generation system that complements traditional ontology development tools. All classes added through pre-defined templates are guaranteed to have OWL equivalence axioms that are used for automatic classification and in some cases inter-ontology linkage. At the same time, the system is simple and intuitive and can be used by most biocurators without extensive training.

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

    Science.gov (United States)

    Pongjit, Kanittha; Chanvorachote, Pithi

    2011-12-01

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

  10. Evaluating the quality of scenarios of short-term wind power generation

    DEFF Research Database (Denmark)

    Pinson, Pierre; Girard, R.

    2012-01-01

    Scenarios of short-term wind power generation are becoming increasingly popular as input to multi-stage decision-making problems e.g. multivariate stochastic optimization and stochastic programming. The quality of these scenarios is intuitively expected to substantially impact the benets from...... their use in decision-making. So far however, their verication is almost always focused on their marginal distributions for each individual lead time only, thus overlooking their temporal interdependence structure. The shortcomings of such an approach are discussed. Multivariate verication tools, as well...... as diagnostic approaches based on event-based verication are then presented. Their application to the evaluation of various sets of scenarios of short-term wind power generation demonstrates them as valuable discrimination tools....

  11. Superoxide radical formation, superoxide dismutase and glutathione reductase activity in the brain of irradiated rats

    International Nuclear Information System (INIS)

    Stanimirovic, D.; Ivanovic, L.; Simovic, M.; Cernak, I.; Savic, J.

    1989-01-01

    In the forebrain cortex, basal ganglia and hippocampus of irradiated rats (whole body, X-ray, 9 Gy), nitroblue-tetrazolium (NBT) reduction was measured as a probe of superoxide radical formation 1 hr, 6 hrs, 24 hrs and 72 hrs after irradiation. Increased superoxide radical formation was found in parallel with increase of superoxide dismutase (SOD) activity and marked decrease of glutathione reductase (GR) activity which is the most pronounced in basal ganglia. The results indicate that in the postradiation period disproportion among free radical production and capacity of brain antioxidative system occurs. This disbalance is more expressed in the brain regions known as selective vulnerable (basal ganglia, hippocampus). (author). 10 refs.; 2 tabs

  12. Environmental implications of electricity generation in an integrated long-term planning framework

    International Nuclear Information System (INIS)

    Turner, Graham M.; West, James

    2012-01-01

    Long-term, integrated modelling of electricity generation capacity and its operational requirements is important for coherent energy policy because of the multi-decadal lifespan of such plant, and because related fuel requirements, water consumption, and greenhouse gas emissions impact other sectors. This paper describes a physical model of electricity generation designed for long-term simulations, including the reproduction of decades of historical data, and its application to key policy questions. The simulation uses a dynamic, physical input–output model for the basic material and energy industries, embedded in an economy-wide stocks and flows framework (SFF). The historical reproduction, illustrated for the state of Victoria, is based on integrating bottom-up technical data on physical processes as inputs, and validating output against top-down aggregate data. We show that while greenhouse gas emissions would decrease significantly with the aggressive introduction of cleaner generation technology, long-term reductions are difficult to maintain against ongoing growth in consumption. Additionally, our sensitivity analysis identifies the importance of rapid action due to the age structure of operating power stations. We also identify significant imposts of alternative power generation on land and water resources, though a business-as-usual scenario would impose greater losses of water resources. - Highlights: ► System-wide dynamic analysis is needed to avoid unintended adverse environmental outcomes. ► Dynamics of long-lived plant is important in transitions for reducing greenhouse gas emissions. ► Large gains in GHG emissions efficiency of generation portfolios fail to maintain low emissions.

  13. Long term trend analysis of emergency power diesel generator reliability in german nuclear power plants

    International Nuclear Information System (INIS)

    Kotthoff, K.; Maqua, M.

    1990-01-01

    The paper deals with a long-term investigation on the availability of diesel generators. This investigation has been performed in two steps in 1980/81 and 1988/89. It is based on the operating experiences of a total of 110 diesel generators in 20 German NPP's. The overall probability of diesel failure during start and short-time operation amounts to about 5E-3/demand. Compared to the result of the first part of the investigation (8E-3/demand) there has been some further improvement of diesel generator performance in recent years. The upper limit calculated for the probability of common mode failures (about 6E-4/demand) is approximately one order of magnitude smaller. The influence of various parameters on the failure probability has been discussed. A statistically significant dependence could not be identified

  14. Modification to ORIGEN2 for generating N Reactor source terms. Volume 1

    International Nuclear Information System (INIS)

    Schwarz, R.A.

    1997-04-01

    This report discusses work that has been done to upgrade the ORIGEN2 code cross sections to be compatible with the WIMS computer code data. Because of the changes in the ORIGEN2 calculations. Details on changes made to the ORIGEN2 computer code and the Radnuc code will be discussed along with additional work that should be done in the future to upgrade both ORIGEN2 and Radnuc. A detailed historical description of how source terms have been generated for N Reactor fuel stored in the K Basins has been generated. The neutron source discussed in this description was generated by the WIMS computer code (Gubbins et al. 1982) because of known shortcomings in the ORIGEN2 (Croff 1980) cross sections. Another document includes a discussion of the ORIGEN2 cross sections

  15. Long-term damage management strategies for optimizing steam generator performance

    International Nuclear Information System (INIS)

    Egan, G.R.; Besuner, P.M.; Fox, J.H.; Merrick, E.A.

    1991-01-01

    Minimizing long-term impact of steam generator operating, maintenance, outage, and replacement costs is the goal of all pressurized water reactor utilities. Recent research results have led to deterministic controls that may be implemented to optimize steam generator performance and to minimize damage accumulation. The real dilemma that utilities encounter is the decision process that needs to be made in the face of uncertain data. Some of these decisions involve the frequency and extent of steam generator eddy current tube inspections; the definition of operating conditions to minimize the rate of corrosion reactions (T (hot) , T (cold) ; and the imposition of strict water quality management guidelines. With finite resources, how can a utility decide which damage management strategy provides the most return for its investment? Aptech Engineering Services, Inc. (APTECH) developed a damage management strategy that starts from a deterministic analysis of a current problem- primary water stress corrosion cracking (PWSCC). The strategy involves a probabilistic treatment that results in long-term performance optimization. By optimization, we refer to minimizing the total cost of operating the steam generator. This total includes the present value costs of operations, maintenance, outages, and replacements. An example of the application of this methodology is presented. (author)

  16. Evaluating the quality of scenarios of short-term wind power generation

    International Nuclear Information System (INIS)

    Pinson, P.; Girard, R.

    2012-01-01

    Highlights: ► Presentation of the desirable properties of wind power generation scenarios. ► Description of various evaluation frameworks (univariate, multivariate, diagnostic). ► Highlighting of the properties of current approaches to scenario generation. ► Guidelines for future evaluation/benchmark exercises. -- Abstract: Scenarios of short-term wind power generation are becoming increasingly popular as input to multistage decision-making problems e.g. multivariate stochastic optimization and stochastic programming. The quality of these scenarios is intuitively expected to substantially impact the benefits from their use in decision-making. So far however, their verification is almost always focused on their marginal distributions for each individual lead time only, thus overlooking their temporal interdependence structure. The shortcomings of such an approach are discussed. Multivariate verification tools, as well as diagnostic approaches based on event-based verification are then presented. Their application to the evaluation of various sets of scenarios of short-term wind power generation demonstrates them as valuable discrimination tools.

  17. A novel inclusion of intermittent generation resources in long term energy auctions

    International Nuclear Information System (INIS)

    Marambio, Rodrigo; Rudnick, Hugh

    2017-01-01

    Long term energy auctions are positioning as a valuable tool in order to attract new investments into power systems, especially in Latin American countries where emergent economies characteristics and their correspondent risks are usually present. Even though the focus of these auctions is the long term, there are short term issues involved which actual auction designs fail to include, resulting in an energy allocation that is not necessarily optimal for the system, a condition which becomes more evident in the presence of intermittent renewable technologies. A novel mechanism is formulated to obtain the optimal allocation in long term energy auctions, considering short term generation profiles from both intermittent and conventional base load technologies, and also their risk aversions. The proposed mechanism is developed and simulations are made for some scenarios in the Chilean power market, with different levels of renewable penetration. Significant cost savings are achieved for the final consumers in relation to energy purchases, in comparison with a mechanism that follows the demand profile. As more renewable intermittent capacity enters the power system it is evident the need for changes in the energy auctions allocation mechanisms, including elements to exploit the synergies among participants in the short term. - Highlights: • Risk management consideration in technology neutral auctions allocation. • Allocation mechanism in technology neutral auctions with intermittent technologies. • Renewable and conventional technologies energy auction offer curves. • Increase bid prices in auctions as a consequence of solar technology support.

  18. X-ray effects of lens DNA-implications of superoxide (O2.-)

    International Nuclear Information System (INIS)

    Srivastava, V.K.; Richards, R.D.; Varma, S.D.

    1983-01-01

    The photocemical generation of superoxide (O 2 .-) during in vitro exposure of bovine lenses induced damage in the structure of lens DNA as indicated by hyperchromicity and Tm measurements. The damage in lens DNA was significantly protected by the inclusion of superoxide dismutase (SOD), glutathione (GSH) and ascorbate in the incubation medium before X-ray exposure. The protection by SOD, GSH and ascorbate occurred due to their interaction with O 2 .- radicals. These results thus indicate the deleterious effect of O 2 .- in lens physiology and the protective role of such compounds against radiation damage. (author)

  19. Superoxide dismutase in radioresistant PC-3 human prostate carcinoma cells

    International Nuclear Information System (INIS)

    Prokopovic, J.; Adzic M; Niciforovic, A.; Vucic, V.; Zaric, B.; Radojcic, M. B.

    2006-01-01

    The molecular mechanism of gamma-ionizing radiation (IR) resistance of human prostate cancer cells PC-3 is not known. Since low-LET-IR effects are primarily achieved through generation of reactive oxygen species (ROS), IR-induced expression of ROS-metabolizing antioxidant enzymes, Mn- and CuZn-superoxide dismutase (Mn- and CuZnSOD) and catalase (CAT), and their upstream regulator transcription factor NFκB was followed. Significant elevation of both SODs was found in cells irradiated with 10- and 20 Gy, while CAT and NFκB expression was unchanged. Since, such conditions lead to accumulation of H 2 O 2 , it is concluded that radioresistance of PC-3 cells may emerge from positive feed-forward vicious circle established between H 2 O 2 activation of NFκB and elevated MnSOD activity. (author)

  20. Particle generation methods applied in large-scale experiments on aerosol behaviour and source term studies

    International Nuclear Information System (INIS)

    Swiderska-Kowalczyk, M.; Gomez, F.J.; Martin, M.

    1997-01-01

    In aerosol research aerosols of known size, shape, and density are highly desirable because most aerosols properties depend strongly on particle size. However, such constant and reproducible generation of those aerosol particles whose size and concentration can be easily controlled, can be achieved only in laboratory-scale tests. In large scale experiments, different generation methods for various elements and compounds have been applied. This work presents, in a brief from, a review of applications of these methods used in large scale experiments on aerosol behaviour and source term. Description of generation method and generated aerosol transport conditions is followed by properties of obtained aerosol, aerosol instrumentation used, and the scheme of aerosol generation system-wherever it was available. An information concerning aerosol generation particular purposes and reference number(s) is given at the end of a particular case. These methods reviewed are: evaporation-condensation, using a furnace heating and using a plasma torch; atomization of liquid, using compressed air nebulizers, ultrasonic nebulizers and atomization of liquid suspension; and dispersion of powders. Among the projects included in this worked are: ACE, LACE, GE Experiments, EPRI Experiments, LACE-Spain. UKAEA Experiments, BNWL Experiments, ORNL Experiments, MARVIKEN, SPARTA and DEMONA. The aim chemical compounds studied are: Ba, Cs, CsOH, CsI, Ni, Cr, NaI, TeO 2 , UO 2 Al 2 O 3 , Al 2 SiO 5 , B 2 O 3 , Cd, CdO, Fe 2 O 3 , MnO, SiO 2 , AgO, SnO 2 , Te, U 3 O 8 , BaO, CsCl, CsNO 3 , Urania, RuO 2 , TiO 2 , Al(OH) 3 , BaSO 4 , Eu 2 O 3 and Sn. (Author)

  1. Committing to coal and gas: Long-term contracts, regulation, and fuel switching in power generation

    Science.gov (United States)

    Rice, Michael

    Fuel switching in the electricity sector has important economic and environmental consequences. In the United States, the increased supply of gas during the last decade has led to substantial switching in the short term. Fuel switching is constrained, however, by the existing infrastructure. The power generation infrastructure, in turn, represents commitments to specific sources of energy over the long term. This dissertation explores fuel contracts as the link between short-term price response and long-term plant investments. Contracting choices enable power plant investments that are relationship-specific, often regulated, and face uncertainty. Many power plants are subject to both hold-up in investment and cost-of-service regulation. I find that capital bias is robust when considering either irreversibility or hold-up due to the uncertain arrival of an outside option. For sunk capital, the rental rate is inappropriate for determining capital bias. Instead, capital bias depends on the regulated rate of return, discount rate, and depreciation schedule. If policies such as emissions regulations increase fuel-switching flexibility, this can lead to capital bias. Cost-of-service regulation can shorten the duration of a long-term contract. From the firm's perspective, the existing literature provides limited guidance when bargaining and writing contracts for fuel procurement. I develop a stochastic programming framework to optimize long-term contracting decisions under both endogenous and exogenous sources of hold-up risk. These typically include policy changes, price shocks, availability of fuel, and volatility in derived demand. For price risks, the optimal contract duration is the moment when the expected benefits of the contract are just outweighed by the expected opportunity costs of remaining in the contract. I prove that imposing early renegotiation costs decreases contract duration. Finally, I provide an empirical approach to show how coal contracts can limit

  2. Manganese superoxide dismutase and breast cancer recurrence

    DEFF Research Database (Denmark)

    Cronin-Fenton, Deirdre P; Christensen, Mariann; Lash, Timothy L

    2014-01-01

    BACKGROUND: Manganese superoxide dismutase (MnSOD) inhibits oxidative damage and cancer therapy effectiveness. A polymorphism in its encoding gene (SOD2: Val16Ala rs4880) may confer poorer breast cancer survival, but data are inconsistent. We examined the association of SOD2 genotype and breast......-metastatic breast cancer from 1990-2001, received adjuvant Cyclo, and were registered in the Danish Breast Cancer Cooperative Group. We identified 118 patients with BCR and 213 matched breast cancer controls. We genotyped SOD2 and used conditional logistic regression to compute the odds ratio (OR) and associated 95...... cancer recurrence (BCR) among patients treated with cyclophosphamide-based chemotherapy (Cyclo). We compared our findings with published studies using meta-analyses. METHODS: We conducted a population-based case-control study of BCR among women in Jutland, Denmark. Subjects were diagnosed with non...

  3. Long-term power generation expansion planning with short-term demand response: Model, algorithms, implementation, and electricity policies

    Science.gov (United States)

    Lohmann, Timo

    Electric sector models are powerful tools that guide policy makers and stakeholders. Long-term power generation expansion planning models are a prominent example and determine a capacity expansion for an existing power system over a long planning horizon. With the changes in the power industry away from monopolies and regulation, the focus of these models has shifted to competing electric companies maximizing their profit in a deregulated electricity market. In recent years, consumers have started to participate in demand response programs, actively influencing electricity load and price in the power system. We introduce a model that features investment and retirement decisions over a long planning horizon of more than 20 years, as well as an hourly representation of day-ahead electricity markets in which sellers of electricity face buyers. This combination makes our model both unique and challenging to solve. Decomposition algorithms, and especially Benders decomposition, can exploit the model structure. We present a novel method that can be seen as an alternative to generalized Benders decomposition and relies on dynamic linear overestimation. We prove its finite convergence and present computational results, demonstrating its superiority over traditional approaches. In certain special cases of our model, all necessary solution values in the decomposition algorithms can be directly calculated and solving mathematical programming problems becomes entirely obsolete. This leads to highly efficient algorithms that drastically outperform their programming problem-based counterparts. Furthermore, we discuss the implementation of all tailored algorithms and the challenges from a modeling software developer's standpoint, providing an insider's look into the modeling language GAMS. Finally, we apply our model to the Texas power system and design two electricity policies motivated by the U.S. Environment Protection Agency's recently proposed CO2 emissions targets for the

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

    Science.gov (United States)

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

    2017-10-01

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

  5. A Novel Hybrid Model for Short-Term Forecasting in PV Power Generation

    Directory of Open Access Journals (Sweden)

    Yuan-Kang Wu

    2014-01-01

    Full Text Available The increasing use of solar power as a source of electricity has led to increased interest in forecasting its power output over short-time horizons. Short-term forecasts are needed for operational planning, switching sources, programming backup, reserve usage, and peak load matching. However, the output of a photovoltaic (PV system is influenced by irradiation, cloud cover, and other weather conditions. These factors make it difficult to conduct short-term PV output forecasting. In this paper, an experimental database of solar power output, solar irradiance, air, and module temperature data has been utilized. It includes data from the Green Energy Office Building in Malaysia, the Taichung Thermal Plant of Taipower, and National Penghu University. Based on the historical PV power and weather data provided in the experiment, all factors that influence photovoltaic-generated energy are discussed. Moreover, five types of forecasting modules were developed and utilized to predict the one-hour-ahead PV output. They include the ARIMA, SVM, ANN, ANFIS, and the combination models using GA algorithm. Forecasting results show the high precision and efficiency of this combination model. Therefore, the proposed model is suitable for ensuring the stable operation of a photovoltaic generation system.

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

    Science.gov (United States)

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

    2018-05-01

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

  7. Mathematical and numerical analysis of the resistive magnetohydrodynamics system with self-generated magnetic field terms

    International Nuclear Information System (INIS)

    Wolff, Marc

    2011-01-01

    This work is devoted to the construction of numerical methods that allow the accurate simulation of inertial confinement fusion (ICF) implosion processes by taking self-generated magnetic field terms into account. In the sequel, we first derive a two-temperature resistive magnetohydrodynamics model and describe the considered closure relations. The resulting system of equations is then split in several subsystems according to the nature of the underlying mathematical operator. Adequate numerical methods are then proposed for each of these subsystems. Particular attention is paid to the development of finite volume schemes for the hyperbolic operator which actually is the hydrodynamics or ideal magnetohydrodynamics system depending on whether magnetic fields are considered or not. More precisely, a new class of high-order accurate dimensionally split schemes for structured meshes is proposed using the Lagrange re-map formalism. One of these schemes' most innovative features is that they have been designed in order to take advantage of modern massively parallel computer architectures. This property can for example be illustrated by the dimensionally split approach or the use of artificial viscosity techniques and is practically highlighted by sequential performance and parallel efficiency figures. Hyperbolic schemes are then combined with finite volume methods for dealing with the thermal and resistive conduction operators and taking magnetic field generation into account. In order to study the characteristics and effects of self-generated magnetic field terms, simulation results are finally proposed with the complete two-temperature resistive magnetohydrodynamics model on a test problem that represents the state of an ICF capsule at the beginning of the deceleration phase. (author)

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

    Science.gov (United States)

    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.

  9. Outlook for world nuclear power generation and long-term energy supply and demand situations

    International Nuclear Information System (INIS)

    Matsuo, Yuhji

    2012-01-01

    In this article, the author presents a long-term outlook for the world's nuclear generating capacity, taking into account the nuclear policy changes after Fukushima Daiichi nuclear power plant accident. World primary energy demand will grow from 11.2 billion tons of oil equivalent (toe) in 2009 to 17.3 billion toe in 2035. Along with this rapid increase in global energy consumption, the world's nuclear generating capacity will grow from 392 GW in 2010 to 484 GW in 2020 and 574 GW in 2035 in the 'Reference scenario'. Even in the 'Low nuclear scenario', where the maximum impact of Fukushima accident to the nuclear policies of each government is assumed, it will continue to grow in the future, exceeding 500 GW in 2035. In particular, Asian countries such as China and India will lead the growth both in the energy demand and in the nuclear power capacity. Therefore, it is essential to better ensure the safety of nuclear power generation. It is important for technologically developed countries, including Japan, to make active contributions to the establishment of a global nuclear safety control system. On the other hand, energy security and global warming will continue to be major issues, which will make it indispensable to make the best effort to save energy and expand renewable energy utilization. Japan is competitive in energy-saving and environmental conservation technologies, thus further development and utilization of there technologies should be a key option of Japan's growth growth strategy in the future. (author)

  10. Supervised guiding long-short term memory for image caption generation based on object classes

    Science.gov (United States)

    Wang, Jian; Cao, Zhiguo; Xiao, Yang; Qi, Xinyuan

    2018-03-01

    The present models of image caption generation have the problems of image visual semantic information attenuation and errors in guidance information. In order to solve these problems, we propose a supervised guiding Long Short Term Memory model based on object classes, named S-gLSTM for short. It uses the object detection results from R-FCN as supervisory information with high confidence, and updates the guidance word set by judging whether the last output matches the supervisory information. S-gLSTM learns how to extract the current interested information from the image visual se-mantic information based on guidance word set. The interested information is fed into the S-gLSTM at each iteration as guidance information, to guide the caption generation. To acquire the text-related visual semantic information, the S-gLSTM fine-tunes the weights of the network through the back-propagation of the guiding loss. Complementing guidance information at each iteration solves the problem of visual semantic information attenuation in the traditional LSTM model. Besides, the supervised guidance information in our model can reduce the impact of the mismatched words on the caption generation. We test our model on MSCOCO2014 dataset, and obtain better performance than the state-of-the- art models.

  11. Comparative study of the hydrogen generation during short term station blackout (STSBO) in a BWR

    International Nuclear Information System (INIS)

    Polo-Labarrios, M.A.; Espinosa-Paredes, G.

    2015-01-01

    Highlights: • Comparative study of generation in a simulated STSBO severe accident. • MELCOR and SCDAP/RELAP5 codes were used to understanding the main phenomena. • Both codes present similar thermal-hydraulic behavior for pressure and boil off. • SCDAP/RELAP5 predicts 15.8% lower hydrogen production than MELCOR. - Abstract: The aim of this work is the comparative study of hydrogen generation and the associated parameters in a simulated severe accident of a short-term station blackout (STSBO) in a typical BWR-5 with Mark-II containment. MELCOR (v.1.8.6) and SCDAP/RELAP5 (Mod.3.4) codes were used to understand the main phenomena in the STSBO event through the results comparison obtained from simulations with these codes. Due that the simulation scope of SCDAP/RELAP5 is limited to failure of the vessel pressure boundary, the comparison was focused on in-vessel severe accident phenomena; with a special interest in the vessel pressure, boil of cooling, core temperature, and hydrogen generation. The results show that at the beginning of the scenario, both codes present similar thermal-hydraulic behavior for pressure and boil off of cooling, but during the relocation, the pressure and boil off, present differences in timing and order of magnitude. Both codes predict in similar time the beginning of melting material drop to the lower head. As far as the hydrogen production rate, SCDAP/RELAP5 predicts 15.8% lower production than MELCOR

  12. Short-Term Photovoltaic Power Generation Forecasting Based on Multivariable Grey Theory Model with Parameter Optimization

    Directory of Open Access Journals (Sweden)

    Zhifeng Zhong

    2017-01-01

    Full Text Available Owing to the environment, temperature, and so forth, photovoltaic power generation volume is always fluctuating and subsequently impacts power grid planning and operation seriously. Therefore, it is of great importance to make accurate prediction of the power generation of photovoltaic (PV system in advance. In order to improve the prediction accuracy, in this paper, a novel particle swarm optimization algorithm based multivariable grey theory model is proposed for short-term photovoltaic power generation volume forecasting. It is highlighted that, by integrating particle swarm optimization algorithm, the prediction accuracy of grey theory model is expected to be highly improved. In addition, large amounts of real data from two separate power stations in China are being employed for model verification. The experimental results indicate that, compared with the conventional grey model, the mean relative error in the proposed model has been reduced from 7.14% to 3.53%. The real practice demonstrates that the proposed optimization model outperforms the conventional grey model from both theoretical and practical perspectives.

  13. A long-term view of fossil-fuelled power generation in Europe

    International Nuclear Information System (INIS)

    Tzimas, Evangelos; Georgakaki, Aliki

    2010-01-01

    The paper presents a view into the long term future of fossil-fuelled power generation in the European Union, based on a number of alternative scenarios for the development of the coal, natural gas and CO 2 markets, and the penetration of renewable and nuclear technologies. The new fossil fuelled capacity needed and the likely technology mix are estimated using a cost optimisation model based on the screening curve method, taking into consideration the rate of retirement of the current power plant fleet, the capacity already planned or under construction and the role of carbon capture and storage technologies. This analysis shows that measures to increase both non-fossil-fuel-based power generation and the price of CO 2 are necessary to drive the composition of the European power generation capacity so that the European policy goal of reducing greenhouse gas emissions is achieved. Meeting this goal will however require a high capital investment for the creation of an optimal fossil fuel power plant technology mix.

  14. Lock-in and change: Distributed generation in Denmark in a long-term perspective

    International Nuclear Information System (INIS)

    Vleuten, Erik van der; Raven, Rob

    2006-01-01

    There is a renewed attention for distributed generation (DG) in European electricity sectors, but implementing DG is often problematic. This article studies the current relative success of DG in Denmark. We take into account not only recent drivers of change such as energy policy and green activism, but also long-term stability and change in the electricity supply sector. In particular we analyse the lock-in on centralized electricity supply, that still frustrates DG development elsewhere. We discuss three successive national electricity regimes, analysing regime lock-in and change in terms of technologies, actors, institutions and the position of DG. Our analysis shows that Danish energy policy as well as innovative activity by key actors indeed were crucial to the recent DG revival in Denmark. On the other hand, our long-term perspective shows that Danish energy policy and actor strategies were tuned to specifically Danish opportunities and barriers created during earlier regimes. These include experience with wind turbines and CHP as well as urban municipal and rural cooperative involvement. Copying the Danish energy policy model to other countries, regardless of national specific opportunities and barriers, will therefore not guarantee a similar outcome

  15. Long-Term Experience with First-Generation Implantable Neurostimulation Device in Central Sleep Apnea Treatment.

    Science.gov (United States)

    Fox, Henrik; Bitter, Thomas; Horstkotte, Dieter; Oldenburg, Olaf; Gutleben, Klaus-Jürgen

    2017-05-01

    Sleep-disordered breathing (SDB) and Cheyne-Stokes respiration (CSR) are associated with shorter survival in patients with heart failure. A novel treatment method for this patient group is unilateral phrenic nerve stimulation by the remedē® system (Respicardia Inc., Minnetonka, MN, USA), a transvenously implantable neurostimulation device, which has recently been studied in a large randomized, controlled trial. Previous literature has shown efficacy and safety of the treatment with this first-generation device, but hardly any data are available on long-term clinical parameters, the remedē® device's battery lifetime, device exchangeability, lead position stability, surgical accessibility, and manageability. We performed remedē® device replacements in consecutive patients for battery depletion, and documented clinical parameters, longevity, operation procedure, complications, and difficulties. All patients were on neurostimulation treatment by phrenic nerve neurostimulation when device replacement became necessary. Apnea-hypopnea index (from 45 ± 4/h to 9 ± 4/h), oxygen-desaturation index (from 35 ± 7/h to 7 ± 6/h), and time spent with oxygen saturation of ray documentation of stable lead positions in a long-term setting, no radiation or contrast dye usage was needed and no major complications occurred. In addition, clinical exercise capacity and sleepiness symptoms improved. Novel remedē® device shows sustained therapy efficacy and safety in terms of stable lead positions over 4 years. Long-term phrenic nerve neurostimulation therapy for central SDB/CSR appears feasible in a clinical routine setting. © 2017 Wiley Periodicals, Inc.

  16. Effect of Low Level Cadmium Exposure on Superoxide Dismutase ...

    African Journals Online (AJOL)

    Purpose: To investigate the effect of low level cadmium (Cd) exposure on the activity of superoxide dismutase ... cancer, aging and a diversity of diseases [5]. Superoxide .... responsible for the long biological half-life of cadmium [12]. ... indicator of the balance between the damaging effects and the ... Scand J Work Environ.

  17. Mitochondrial respiration scavenges extramitochondrial superoxide anion via a nonenzymatic mechanism.

    OpenAIRE

    Guidot, D M; Repine, J E; Kitlowski, A D; Flores, S C; Nelson, S K; Wright, R M; McCord, J M

    1995-01-01

    We determined that mitochondrial respiration reduced cytosolic oxidant stress in vivo and scavenged extramitochondrial superoxide anion (O2-.) in vitro. First, Saccharomyces cerevisiae deficient in both the cytosolic antioxidant cupro-zinc superoxide dismutase (Cu,Zn-SOD) and electron transport (Rho0 state) grew poorly (P 0.05) in all yeast. Seco...

  18. Improved thermal source term generation capability for use in performance assessment and system studies

    International Nuclear Information System (INIS)

    King, J.; Rhodes, C.

    1994-01-01

    This paper describes work performed by the Civilian Radioactive Waste Management System (CRWMS) Management and Operating (M ampersand O) Contractor to improve spent nuclear fuel (SNF) waste stream characterization for system studies. It discusses how these new capabilities may be exploited for thermal source term generation for use in repository performance assessment modeling. SNF historical discharges have been exhaustively tracked, and significant effort has gone into capturing, verifying, and electronically managing spent fuel inventory data. Future discharge projections are produced annually by the Energy Information Administration (EIA) using sophisticated computer models. The output of these models is coupled with annually updated SNF historical discharges to produce what is referred to as the open-quotes reactor database.close quotes This database and related data are published in a variety of ways including on magnetic media for consistent use by analysts or other interested parties

  19. Superoxide anion production by human neutrophils activated by Trichomonas vaginalis.

    Science.gov (United States)

    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.

  20. Sources of superoxide/H2O2 during mitochondrial proline oxidation

    Directory of Open Access Journals (Sweden)

    Renata L.S. Goncalves

    2014-01-01

    Full Text Available p53 Inducible gene 6 (PIG6 encodes mitochondrial proline dehydrogenase (PRODH and is up-regulated several fold upon p53 activation. Proline dehydrogenase is proposed to generate radicals that contribute to cancer cell apoptosis. However, there are at least 10 mitochondrial sites that can produce superoxide and/or H2O2, and it is unclear whether proline dehydrogenase generates these species directly, or instead drives production by other sites. Amongst six cancer cell lines, ZR75-30 human breast cancer cells had the highest basal proline dehydrogenase levels, and mitochondria isolated from ZR75-30 cells consumed oxygen and produced H2O2 with proline as sole substrate. Insects use proline oxidation to fuel flight, and mitochondria isolated from Drosophila melanogaster were even more active with proline as sole substrate than ZR75-30 mitochondria. Using mitochondria from these two models we identified the sites involved in formation of superoxide/H2O2 during proline oxidation. In mitochondria from Drosophila the main sites were respiratory complexes I and II. In mitochondria from ZR75-30 breast cancer cells the main sites were complex I and the oxoglutarate dehydrogenase complex. Even with combinations of substrates and respiratory chain inhibitors designed to minimize the contributions of other sites and maximize any superoxide/H2O2 production from proline dehydrogenase itself, there was no significant direct contribution of proline dehydrogenase to the observed H2O2 production. Thus proline oxidation by proline dehydrogenase drives superoxide/H2O2 production, but it does so mainly or exclusively by providing anaplerotic carbon for other mitochondrial dehydrogenases and not by producing superoxide/H2O2 directly.

  1. Long-term impacts of electricity generation systems. Draft technical report

    International Nuclear Information System (INIS)

    1998-01-01

    Estimation of health and environmental impacts in a distant future driven by current electricity generation systems is not a well established scientific field. This issue includes many uncertainties which are seen in many processes of the impact estimation such as valuation techniques of environmental impacts for a long-term, and technology choice and policy options for a long run. When the IAEA held the Technical Committee Meeting on Estimating and Comparing Risks from Energy Systems in the Far Future in October 1997 in Vienna, there were many questions raised up from the participants on these issues. The purpose of this document is to introduce typical discussions at the Meeting, and to give a guidance to the methodological approaches for the readers. The decision making process is not central to this technical document. The main issue explained in the document is the ways of presenting health and environmental impacts in a distant future for decision makers. The primarily targeted readers of this document are, therefore, experts who will make the impact assessment and document the results to governmental offices and/or representatives of general public. For those who further implement decision making study, several documents are available from the IAEA. (in preparation 29]). To provide an effective guidance to the methodological approaches, several issues which are currently recognized as typical examples of the impacts on future generations were chosen. Global climate change, nuclear and non-nuclear wastes, long lived radionuclides dispersing world-wide, land use, and resource depletion are briefly discussed to illustrate several technical difficulties in estimating the impacts in the far future. About technology choice, the discussions illustrated in this document are based on only marginal increase of currently available electricity production systems. For smooth introduction of currently available methodological approaches to readers, issues like future

  2. Profiling of antioxidant superoxide dismutase in saliva of oral submucous fibrosis patients to categorize its diagnosis in varying stages

    International Nuclear Information System (INIS)

    Sirohi, Y.; Shetty, D.C.; Urs, A.B.; Rai, H.C.

    2011-01-01

    Background: Oral submucous fibrosis is a pre malignant condition in Indian and South-East Asia. Role of oxidant-antioxidant in causation and progression of cancer and pre cancers is known. Reactive oxygen species are generated in the oral cavity during chewing areca nut, the major etiological agent in oral submucous fibrosis. Objectives: To see the alterations in the salivary superoxide dismutase levels in various clinical and histopathological grades of oral submucous fibrosis. Materials and Methods: Unstimulated saliva was collected from 25 oral submucous fibrosis patients and age and gender matched controls. The saliva was assessed for superoxide dismutase value by spectrophotometric method using assay kit (Bio Vision Catalog number K335-100). The oral submucous fibrosis cases were grouped into clinical stages and histopathological grades and superoxide dismutase values were compared in different clinical stages and histopathological grades. Results: The superoxide dismutase levels were reduced in oral submucous fibrosis as compared to controls. A steady decline in the levels was seen as the clinical stage and histopathological grade of oral submucous fibrosis advanced. Conclusions: Salivary superoxide dismutase levels can be alternatively used as a surrogate marker for the diagnosis of oral submucous fibrosis. Policy message: Oral physicians should advise the pan chewers to regularly check their salivary superoxide dismutase levels so as to ease the early diagnosis of oral submucous fibrosis. (author)

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

    Science.gov (United States)

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

    2016-12-01

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

  4. Short-term optimal wind power generation capacity in liberalized electricity markets

    International Nuclear Information System (INIS)

    Olsina, Fernando; Roescher, Mark; Larisson, Carlos; Garces, Francisco

    2007-01-01

    Mainly because of environmental concerns and fuel price uncertainties, considerable amounts of wind-based generation capacity are being added to some deregulated power systems. The rapid wind development registered in some countries has essentially been driven by strong subsidizing programs. Since wind investments are commonly isolated from market signals, installed wind capacity can be higher than optimal, leading to distortions of the power prices with a consequent loss of social welfare. In this work, the influence of wind generation on power prices in the framework of a liberalized electricity market has been assessed by means of stochastic simulation techniques. The developed methodology allows investigating the maximal wind capacity that would be profitably deployed if wind investments were subject to market conditions only. For this purpose, stochastic variables determining power prices are accurately modeled. A test system resembling the size and characteristics of the German power system has been selected for this study. The expected value of the optimal, short-term wind capacity is evaluated for a considerable number of random realizations of power prices. The impact of dispersing the wind capacity over statistical independent wind sites has also been evaluated. The simulation results reveal that fuel prices, installation and financing costs of wind investments are very influential parameters on the maximal wind capacity that might be accommodated in a market-based manner

  5. An Advanced Bayesian Method for Short-Term Probabilistic Forecasting of the Generation of Wind Power

    Directory of Open Access Journals (Sweden)

    Antonio Bracale

    2015-09-01

    Full Text Available Currently, among renewable distributed generation systems, wind generators are receiving a great deal of interest due to the great economic, technological, and environmental incentives they involve. However, the uncertainties due to the intermittent nature of wind energy make it difficult to operate electrical power systems optimally and make decisions that satisfy the needs of all the stakeholders of the electricity energy market. Thus, there is increasing interest determining how to forecast wind power production accurately. Most the methods that have been published in the relevant literature provided deterministic forecasts even though great interest has been focused recently on probabilistic forecast methods. In this paper, an advanced probabilistic method is proposed for short-term forecasting of wind power production. A mixture of two Weibull distributions was used as a probability function to model the uncertainties associated with wind speed. Then, a Bayesian inference approach with a particularly-effective, autoregressive, integrated, moving-average model was used to determine the parameters of the mixture Weibull distribution. Numerical applications also are presented to provide evidence of the forecasting performance of the Bayesian-based approach.

  6. An adaptive random search for short term generation scheduling with network constraints.

    Directory of Open Access Journals (Sweden)

    J A Marmolejo

    Full Text Available This paper presents an adaptive random search approach to address a short term generation scheduling with network constraints, which determines the startup and shutdown schedules of thermal units over a given planning horizon. In this model, we consider the transmission network through capacity limits and line losses. The mathematical model is stated in the form of a Mixed Integer Non Linear Problem with binary variables. The proposed heuristic is a population-based method that generates a set of new potential solutions via a random search strategy. The random search is based on the Markov Chain Monte Carlo method. The main key of the proposed method is that the noise level of the random search is adaptively controlled in order to exploring and exploiting the entire search space. In order to improve the solutions, we consider coupling a local search into random search process. Several test systems are presented to evaluate the performance of the proposed heuristic. We use a commercial optimizer to compare the quality of the solutions provided by the proposed method. The solution of the proposed algorithm showed a significant reduction in computational effort with respect to the full-scale outer approximation commercial solver. Numerical results show the potential and robustness of our approach.

  7. Extended-Term Dynamic Simulations with High Penetrations of Photovoltaic Generation.

    Energy Technology Data Exchange (ETDEWEB)

    Concepcion, Ricky James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Elliott, Ryan Thomas [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Donnelly, Matt [Montana Tech., Butte, MT (United States); Sanchez-Gasca, Juan [GE Energy, Schenectady, NY (United States)

    2016-01-01

    The uncontrolled intermittent availability of renewable energy sources makes integration of such devices into today's grid a challenge. Thus, it is imperative that dynamic simulation tools used to analyze power system performance are able to support systems with high amounts of photovoltaic (PV) generation. Additionally, simulation durations expanding beyond minutes into hours must be supported. This report aims to identify the path forward for dynamic simulation tools to accom- modate these needs by characterizing the properties of power systems (with high PV penetration), analyzing how these properties affect dynamic simulation software, and offering solutions for po- tential problems. We present a study of fixed time step, explicit numerical integration schemes that may be more suitable for these goals, based on identified requirements for simulating high PV penetration systems. We also present the alternative of variable time step integration. To help determine the characteristics of systems with high PV generation, we performed small signal sta- bility studies and time domain simulations of two representative systems. Along with feedback from stakeholders and vendors, we identify the current gaps in power system modeling including fast and slow dynamics and propose a new simulation framework to improve our ability to model and simulate longer-term dynamics.

  8. Manganese Superoxide Dismutase: Guardian of the Powerhouse

    Directory of Open Access Journals (Sweden)

    Daret K. St. Clair

    2011-10-01

    Full Text Available 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.

  9. Near-term and next-generation nuclear power plant concepts

    International Nuclear Information System (INIS)

    Shiga, Shigenori; Handa, Norihiko; Heki, Hideaki

    2002-01-01

    Near-term and next-generation nuclear reactors will be required to have high economic competitiveness in the deregulated electricity market, flexibility with respect to electricity demand and investment, and good public acceptability. For near-term reactors in the 2010s, Toshiba is developing an improved advanced boiling water reactor (ABWR) based on the present ABWR with newly rationalized systems and components; a construction period of 36 months, one year shorter than the current period; and a power lineup ranging from 800 MWe to 1,600 MWe. For future reactors in the 2020s and beyond, Toshiba is developing the ABWR-II for large-scale, centralized power sources; a supercritical water-cooled power reactor with high thermal efficiency for medium-scale power sources; a modular reactor with siting flexibility for small-scale power sources; and a small, fast neutron reactor with inherent safety for independent power sources. From the viewpoint of efficient uranium resource utilization, a low-moderation BWR core with a high conversion factor is also being developed. (author)

  10. Phagocytosis of mast cell granules results in decreased macrophage superoxide production

    Directory of Open Access Journals (Sweden)

    Bobby A. Shah

    1995-01-01

    Full Text Available The mechanism by which phagocytosed mast cell granules (MCGs inhibit macrophage superoxide production has not been defined. In this study, rat peritoneal macrophages were co-incubated with either isolated intact MCGs or MCG-sonicate, and their respiratory burst capacity and morphology were studied. Co-incubation of macrophages with either intact MCGs or MCG-sonicate resulted in a dose-dependent inhibition of superoxide- mediated cytochrome c reduction. This inhibitory effect was evident within 5 min of incubation and with MCG-sonicate was completely reversed when macrophages were washed prior to activation with PMA. In the case of intact MCGs, the inhibitory effect was only partially reversed by washing after a prolonged co-incubation time. Electron microscopic analyses revealed that MCGs were rapidly phagocytosed by macrophages and were subsequently disintegrated within the phagolysosomes. Assay of MCGs for superoxide dismutase (SOD revealed the presence of significant activity of this enzyme. A comparison of normal macrophages and those containing phagocytosed MCGs did not reveal a significant difference in total SOD activity. It is speculated that, although there was no significant increase in total SOD activity in macrophages containing phagocytosed MCGs, the phagocytosed MCGs might cause a transient increase in SOD activity within the phagolysosomes. This transient rise in SOD results in scavenging of the newly generated superoxide. Alternatively, MCG inhibition of NADPH oxidase would explain the reported observations.

  11. A three-stage short-term electric power planning procedure for a generation company in a liberalized market

    International Nuclear Information System (INIS)

    Nabona, Narcis; Pages, Adela

    2007-01-01

    In liberalized electricity markets, generation companies bid their hourly generation in order to maximize their profit. The optimization of the generation bids over a short-term weekly period must take into account the action of the competing generation companies and the market-price formation rules and must be coordinated with long-term planning results. This paper presents a three stage optimization process with a data analysis and parameter calculation, a linearized unit commitment, and a nonlinear generation scheduling refinement. Although the procedure has been developed from the experience with the Spanish power market, with minor adaptations it is also applicable to any generation company participating in a competitive market system. (author)

  12. Ursolic acid inhibits superoxide production in activated neutrophils and attenuates trauma-hemorrhage shock-induced organ injury in rats.

    Directory of Open Access Journals (Sweden)

    Tsong-Long Hwang

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

  13. Effects of Altered Levels of Extracellular Superoxide Dismutase and Irradiation on Hippocampal Neurogenesis in Female Mice

    International Nuclear Information System (INIS)

    Zou, Yani; Leu, David; Chui, Jennifer; Fike, John R.; Huang, Ting-Ting

    2013-01-01

    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

  14. Attenuation of 6-hydroxydopamine-induced dopaminergic nigrostriatal lesions in superoxide dismutase transgenic mice

    International Nuclear Information System (INIS)

    Cadet, J.L.; Hirata, H.; Asanuma, M.

    1998-01-01

    6-Hydroxydopamine is a neurotoxin that produces degeneration of the nigrostriatal dopaminergic pathway in rodents. Its toxicity is thought to involve the generation of superoxide anion secondary to its autoxidation. To examine the effects of the overexpression of Cu,Zn-superoxide dismutase activity on 6-hydroxydopamine-induced dopaminergic neuronal damage, we have measured the effects of 6-hydroxydopamine on striatal and nigral dopamine transporters and nigral tyrosine hydroxylase-immunoreactive neurons in Cu,Zn-superoxide dismutase transgenic mice. Intracerebroventricular injection of 6-hydroxydopamine (50 μg) in non-transgenic mice produced reductions in the size of striatal area and an enlargement of the cerebral ventricle on both sides of the brains of mice killed two weeks after the injection. In addition, 6-hydroxydopamine caused marked decreases in striatal and nigral [ 125 I]RTI-121-labelled dopamine transporters not only on the injected side but also on the non-injected side of non-transgenic mice; this was associated with decreased cell number and size of tyrosine hydroxylase-immunoreactive dopamine neurons in the substantia nigra pars compacta on both sides in these mice. In contrast, superoxide dismutase transgenic mice were protected against these neurotoxic effects of 6-hydroxydopamine, with the homozygous transgenic mice showing almost complete protection.These results provide further support for a role of superoxide anion in the toxic effects of 6-hydroxydopamine. They also provide further evidence that reactive oxygen species may be the main determining factors in the neurodegenerative effects of catecholamines. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  15. Long-term generation scheduling of Xiluodu and Xiangjiaba cascade hydro plants considering monthly streamflow forecasting error

    International Nuclear Information System (INIS)

    Xie, Mengfei; Zhou, Jianzhong; Li, Chunlong; Zhu, Shuang

    2015-01-01

    Highlights: • Monthly streamflow forecasting error is considered. • An improved parallel progressive optimality algorithm is proposed. • Forecasting dispatching chart is manufactured accompanying with a set of rules. • Applications in Xiluodu and Xiangjiaba cascade hydro plants. - Abstract: Reliable streamflow forecasts are very significant for reservoir operation and hydropower generation. But for monthly streamflow forecasting, the forecasting result is unreliable and it is hard to be utilized, although it has a certain reference value for long-term hydro generation scheduling. Current researches mainly focus on deterministic scheduling, and few of them consider the uncertainties. So this paper considers the forecasting error which exists in monthly streamflow forecasting and proposes a new long-term hydro generation scheduling method called forecasting dispatching chart for Xiluodu and Xiangjiaba cascade hydro plants. First, in order to consider the uncertainties of inflow, Monte Carlo simulation is employed to generate streamflow data according to the forecasting value and error distribution curves. Then the large amount of data obtained by Monte Carlo simulation is used as inputs for long-term hydro generation scheduling model. Because of the large amount of streamflow data, the computation speed of conventional algorithm cannot meet the demand. So an improved parallel progressive optimality algorithm is proposed to solve the long-term hydro generation scheduling problem and a series of solutions are obtained. These solutions constitute an interval set, unlike the unique solution in the traditional deterministic long-term hydro generation scheduling. At last, the confidence intervals of the solutions are calculated and forecasting dispatching chart is proposed as a new method for long-term hydro generation scheduling. A set of rules are proposed corresponding to forecasting dispatching chart. The chart is tested for practical operations and achieves

  16. Is the "First-Generation Student" Term Useful for Understanding Inequality? the Role of Intersectionality in Illuminating the Implications of an Accepted--Yet Unchallenged--Term

    Science.gov (United States)

    Nguyen, Thai-Huy; Nguyen, Bach Mai Dolly

    2018-01-01

    First-generation students (FGSs) have received a great deal of attention in education research, practice, and policy. The difficulty of understanding and subsequently addressing the various and persistent configurations of inequality associated with FGSs lies with the complicated yet obscure state of the FGS term itself. Leaving the term…

  17. A Comparison between Generation X and Generation Y in Terms of Individual Innovativeness Behavior: The Case of Turkish Health Professionals

    OpenAIRE

    Sema Yigit; Kadir Aksay

    2015-01-01

    Today the criterion of innovation has become a paradigm for all institutions to maintain their success. Innovation is essential for service industry as well as production industry. It is the individual that is in the center of innovation, which can be defined as the difference between a good idea and a good product. The innovative work behavior of individuals is an area that needs to be scrutinized in terms of innovativeness. Because innovation directly effects the quality of life, it has a s...

  18. Sauroxine reduces memory retention in rats and impairs hippocampal long-term potentiation generation.

    Science.gov (United States)

    Vallejo, Mariana; Carlini, Valeria; Gabach, Laura; Ortega, M G; L Cabrera, José; de Barioglio, Susana Rubiales; Pérez, Mariela; Agnese, Alicia M

    2017-07-01

    In the present paper it was investigated the role of sauroxine, an alkaloid of Phlegmariurus saururus, as a modulator of some types of learning and memory, considering the potential nootropic properties previously reported for the alkaloid extract and the main alkaloid sauroine. Sauroxine was isolated by means of an alkaline extraction, purified by several chromatographic techniques, and assayed in electrophysiological experiments on rat hippocampus slices, tending towards the elicitation of the long-term potentiation (LTP) phenomena. It was also studied the effects of intrahippocampal administration of sauroxine on memory retention in vivo using a Step-down test. Being the bio distribution of a drug an important parameter to be considered, the concentration of sauroxine in rat brain was determined by GLC-MS. Sauroxine blocked LTP generation at both doses used, 3.65 and 3.610 -2 μM. In the behavioral test, the animals injected with this alkaloid (3.6510 -3 nmol) exhibited a significant decrease on memory retention compared with control animals. It was also showed that sauroxine reached the brain (3.435μg/g tissue), after an intraperitoneal injection, displaying its ability to cross the blood-brain barrier. Thus, sauroxine demonstrated to exert an inhibition on these mnemonic phenomena. The effect here established for 1 is defeated by other constituents according to the excellent results obtained for P. saururus alkaloid extract as well as for the isolated alkaloid sauroine. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  19. Superoxide Dismutase 2 is dispensable for platelet function.

    Science.gov (United States)

    Fidler, Trevor P; Rowley, Jesse W; Araujo, Claudia; Boudreau, Luc H; Marti, Alex; Souvenir, Rhonda; Dale, Kali; Boilard, Eric; Weyrich, Andrew S; Abel, E Dale

    2017-10-05

    Increased intracellular reactive oxygen species (ROS) promote platelet activation. The sources of platelet-derived ROS are diverse and whether or not mitochondrial derived ROS, modulates platelet function is incompletely understood. Studies of platelets from patients with sickle cell disease, and diabetes suggest a correlation between mitochondrial ROS and platelet dysfunction. Therefore, we generated mice with a platelet specific knockout of superoxide dismutase 2 (SOD2-KO) to determine if increased mitochondrial ROS increases platelet activation. SOD2-KO platelets demonstrated decreased SOD2 activity and increased mitochondrial ROS, however total platelet ROS was unchanged. Mitochondrial function and content were maintained in non-stimulated platelets. However SOD2-KO platelets demonstrated decreased mitochondrial function following thrombin stimulation. In vitro platelet activation and spreading was normal and in vivo, deletion of SOD2 did not change tail-bleeding or arterial thrombosis indices. In pathophysiological models mediated by platelet-dependent immune mechanisms such as sepsis and autoimmune inflammatory arthritis, SOD2-KO mice were phenotypically identical to wildtype controls. These data demonstrate that increased mitochondrial ROS does not result in platelet dysfunction.

  20. Oxidative stress and superoxide dismutase activity in brain of rats ...

    African Journals Online (AJOL)

    JTEkanem

    effect of superoxide dismutase (SOD) activity in brain homogenates of Wistar rats. Oxidative stress measured as ..... on the brain and nervous system of humans as handlers and ... environment may be at higher health risk in that their internal ...

  1. Long-term fiscal implications of funding assisted reproduction: a generational accounting model for Spain

    Directory of Open Access Journals (Sweden)

    R. Matorras

    2015-12-01

    Full Text Available The aim of this study was to assess the lifetime economic benefits of assisted reproduction in Spain by calculating the return on this investment. We developed a generational accounting model that simulates the flow of taxes paid by the individual, minus direct government transfers received over the individual’s lifetime. The difference between discounted transfers and taxes minus the cost of either IVF or artificial insemination (AI equals the net fiscal contribution (NFC of a child conceived through assisted reproduction. We conducted sensitivity analysis to test the robustness of our results under various macroeconomic scenarios. A child conceived through assisted reproduction would contribute €370,482 in net taxes to the Spanish Treasury and would receive €275,972 in transfers over their lifetime. Taking into account that only 75% of assisted reproduction pregnancies are successful, the NFC was estimated at €66,709 for IVF-conceived children and €67,253 for AI-conceived children. The return on investment for each euro invested was €15.98 for IVF and €18.53 for AI. The long-term NFC of a child conceived through assisted reproduction could range from €466,379 to €-9,529 (IVF and from €466,923 to €-8,985 (AI. The return on investment would vary between €-2.28 and €111.75 (IVF, and €-2.48 and €128.66 (AI for each euro invested. The break-even point at which the financial position would begin to favour the Spanish Treasury ranges between 29 and 41 years of age. Investment in assisted reproductive techniques may lead to positive discounted future fiscal revenue, notwithstanding its beneficial psychological effect for infertile couples in Spain.

  2. Applying a CAD-generated imaging marker to assess short-term breast cancer risk

    Science.gov (United States)

    Mirniaharikandehei, Seyedehnafiseh; Zarafshani, Ali; Heidari, Morteza; Wang, Yunzhi; Aghaei, Faranak; Zheng, Bin

    2018-02-01

    Although whether using computer-aided detection (CAD) helps improve radiologists' performance in reading and interpreting mammograms is controversy due to higher false-positive detection rates, objective of this study is to investigate and test a new hypothesis that CAD-generated false-positives, in particular, the bilateral summation of false-positives, is a potential imaging marker associated with short-term breast cancer risk. An image dataset involving negative screening mammograms acquired from 1,044 women was retrospectively assembled. Each case involves 4 images of craniocaudal (CC) and mediolateral oblique (MLO) view of the left and right breasts. In the next subsequent mammography screening, 402 cases were positive for cancer detected and 642 remained negative. A CAD scheme was applied to process all "prior" negative mammograms. Some features from CAD scheme were extracted, which include detection seeds, the total number of false-positive regions, an average of detection scores and the sum of detection scores in CC and MLO view images. Then the features computed from two bilateral images of left and right breasts from either CC or MLO view were combined. In order to predict the likelihood of each testing case being positive in the next subsequent screening, two logistic regression models were trained and tested using a leave-one-case-out based cross-validation method. Data analysis demonstrated the maximum prediction accuracy with an area under a ROC curve of AUC=0.65+/-0.017 and the maximum adjusted odds ratio of 4.49 with a 95% confidence interval of [2.95, 6.83]. The results also illustrated an increasing trend in the adjusted odds ratio and risk prediction scores (pbreast cancer risk.

  3. Chemistry of superoxide radical in seawater: CDOM associated sink of superoxide in coastal waters

    Energy Technology Data Exchange (ETDEWEB)

    Goldstone, J.V.; Voelker, B.M.

    2000-03-15

    Colored dissolved organic matter (CDOM) and humic substances contain a nonmetallic redox-cycling component capable of catalyzing superoxide (O{sub 2}{sup {minus}}) dismutation. First-order rate coefficients (k{sub pseudo}) measured for this O{sub 2}{sup {minus}} sink in a number of coastal and Chesapeake Bay water samples range up to 1.4s{sup {minus}1}, comparable in magnitude to catalyzed dismutation by Cu species. A significant (r{sup 2}=0.73) correlation is observed between k{sub pseudo} and the optical absorption and salinity of individual coastal water samples, suggesting an association with non-marine-derived CDOM. The activity of this sink is not changed by acidification or boiling of samples but is removed by photooxidation, indicating that it is an organic compound, but that it is neither enzymatic nor likely to consist of tightly bound metals. The stoichiometry of hydrogen peroxide formation from O{sub 2}{sup {minus}} decay indicates that this sink is capable of a redox cycle catalyzing the dismutation of O{sub 2}{sup {minus}}. This CDOM sink combined with the organic copper sink previously described will produce a steady-state superoxide concentration in coastal waters that is 100--1000-fold lower than that predicted from bimolecular dismutation alone. Catalyzed O{sub 2}{sup {minus}} decay was also observed in a variety of humic and fulvic acid samples, possibly occurring through quinone functionalities. Although the presence of quinone moieties in humic and fulvic acids has been demonstrated, there do not appear to be good correlations between several measures of quinone content and the O{sub 2}{sup {minus}} dismutation rates of these samples.

  4. Long-Term Reserve Expansion of Power Systems With High Wind Power Penetration Using Universal Generating Function Methods

    DEFF Research Database (Denmark)

    DING, YI; Wang, Peng; Goel, Lalit

    2010-01-01

    from long term planning point of view utilizing universal generating function (UGF) methods. The reliability models of wind farms and conventional generators are represented as the correspondin UGFs and the special operators for these UGFs are defined to evaluate the customer and the system...... reliabilities. The effect of transmission network on customer reliabilities is also considered in the system UGF. The power output models of wind turbine generators in a wind farm considering wind speed correlation and un-correlation are developed, respectively. A reliability-based reserve expansion method...

  5. Nuclear energy in medium and long term energy generation of Turkey

    International Nuclear Information System (INIS)

    Sarici, L. E.; Yilmaz, S.; Guray, B. S.

    2001-01-01

    In this study; objectives and activities of Nuclear Power Plants Department and Turkish Electricity Generation and Transmission Corporation is briefly mentioned. A brief history of electricity generation, development of Turkish electrical energy sector and development of the installed capacity of country is presented. The history and future perspectives of AKZuyu Nuclear Power Plant Project is sharply outlined. In the light of the current situation in electricity generation and demand projections, importance of nuclear power among the other future electricity generation alternatives of Turkey is underlined

  6. Neuroprotection from NMDA excitotoxic lesion by Cu/Zn superoxide dismutase gene delivery to the postnatal rat brain by a modular protein vector

    OpenAIRE

    Peluffo, Hugo; Acarin, Laia; Arís, Anna; González, Pau; Villaverde, Antoni; Castellano, Bernardo; González, Berta

    2006-01-01

    Abstract Background Superoxide mediated oxidative stress is a key neuropathologic mechanism in acute central nervous system injuries. We have analyzed the neuroprotective efficacy of the transient overexpression of antioxidant enzyme Cu/Zn Superoxide dismutase (SOD) after excitotoxic injury to the immature rat brain by using a recently constructed modular protein vector for non-viral gene delivery termed NLSCt. For this purpose, animals were injected with the NLSCt vector carrying the Cu/Zn S...

  7. Long-term field test of solar PV power generation using one-axis 3-position sun tracker

    KAUST Repository

    Huang, B.J.; Ding, W.L.; Huang, Y.C.

    2011-01-01

    The 1 axis-3 position (1A-3P) sun tracking PV was built and tested to measure the daily and long-term power generation of the solar PV system. A comparative test using a fixed PV and a 1A-3P tracking PV was carried out with two identical stand

  8. Impact of HVAC filter on indoor air quality in terms of ozone removal and carbonyls generation

    Science.gov (United States)

    Lin, Chi-Chi; Chen, Hsuan-Yu

    2014-06-01

    This study aims at detecting ozone removal rates and corresponding carbonyls generated by ozone reaction with HVAC filters from various building, i.e., shopping mall, school, and office building. Studies were conducted in a small-scale environmental chamber. By examining dust properties including organic carbon proportion and specific surface area of dusts adsorbed on filters along with ozone removal rates and carbonyls generation rate, the relationship among dust properties, ozone removal rates, and carbonyls generation was identified. The results indicate a well-defined positive correlation between ozone removal efficiency and carbonyls generation on filters, as well as a positive correlation among the mass of organic carbon on filters, ozone removal efficiency and carbonyls generations.

  9. Global long-term cost dynamics of offshore wind electricity generation

    NARCIS (Netherlands)

    Gernaat, David E H J; Van Vuuren, Detlef P.; Van Vliet, Jasper; Sullivan, Patrick; Arent, Douglas J.

    2014-01-01

    Using the IMAGE/TIMER (The Targets IMage Energy Regional) long-term integrated assessment model, this paper explores the regional and global potential of offshore wind to contribute to global electricity production. We develop long-term cost supply curve for offshore wind, a representation of the

  10. Deformation of the three-term recursion relation and generation of new orthogonal polynomials

    International Nuclear Information System (INIS)

    Alhaidari, A D

    2002-01-01

    We find solutions for a linear deformation of the three-term recursion relation. The orthogonal polynomials of the first and second kind associated with the deformed relation are obtained. The new density (weight) function is written in terms of the original one and the deformation parameters

  11. Status of Siemens steam generator design and measures to assure continuous long-term reliable operation

    International Nuclear Information System (INIS)

    Hoch, G.

    1999-01-01

    Operating pressurized water reactors with U-tube steam generators have encountered difficulties with either one or a combination of inadequate material selection, poor design or manufacturing and an insufficient water chemistry control which resulted in excessive tube degradation. In contrast to the above mentioned problems, steam generators from Siemens/KWU are proving by operating experience that all measures undertaken at the design stage as well as during the operating and maintenance phase were effective enough to counteract any tube corrosion phenomena or other steam generator related problem. An Integrated Service Concept has been developed, applied and wherever necessary improved in order to ensure reliable steam generator operation. The performance of the steam generators is updated continuously, evaluated and implemented in lifetime databases. The main indicator for steam generator integrity are the results of the eddy current testing of the steam generator tubes. Tubes with indications are rated with lifetime threshold values and if necessary plugged, based on individual assessment criteria.(author)

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

    Science.gov (United States)

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

    2017-12-01

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

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

    Science.gov (United States)

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

    2011-07-01

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

  14. Evaluation of the long-term power generation mix: The case study of South Korea's energy policy

    International Nuclear Information System (INIS)

    Min, Daiki; Chung, Jaewoo

    2013-01-01

    This paper presents a practical portfolio model for the long-term power generation mix problem. The proposed model optimizes the power generation mix by striking a trade-off between the expected cost of power generation and its variability. We use Monte Carlo simulation techniques to consider the uncertainty associated with future electricity demand, fuel prices and their correlations, and the capital costs of power plants. Unlike in the case of conventional power generation mix models, we employ CVaR (Conditional Value-at-Risk) in designing variability to consider events that are rare but enormously expensive. A comprehensive analysis on South Korea's generation policy using the portfolio model shows that a large annual cost is additionally charged to substitute a portion of nuclear energy with other alternatives. Nonetheless, if Korea has to reduce its dependency on nuclear energy because of undermined social receptivity from the Fukushima disaster, it turns out that LNG or coal could be a secure candidate from an economic perspective. - Author-Highlights: • We develop a stochastic optimization model for long-term power generation mix. • Monte Carlo sampling method and scenario trees are used to solve the model. • The model is verified using the data provided by Korean government. • We evaluate Korea's existing nuclear expansion policy. • We analyze the cost of replacing nuclear energy with others in South Korea

  15. Foresight of nuclear generation at long term in Mexico;Prospectiva de la generacion nucleoelectrica en Mexico a largo plazo

    Energy Technology Data Exchange (ETDEWEB)

    Guadarrama L, R.; Sanchez R, O. E.; Martin del Campo M, C., E-mail: rodrigoguadarrama28@hotmail.co [UNAM, Ciudad Universitaria, 04510 Mexico D. F. (Mexico)

    2009-10-15

    This paper presents an analysis of the nuclear generation expansion for the period 2008-2030. The main objective is to plan the expansion of electrical generation system at long term taking into account four decision criteria. These are, the total cost of generation, the risk associated whit changes in fuel prices, the diversity of the generation park and polluting emissions of global impact (greenhouse effect gases) and local effects (acid rain and suspended particles). The analyzed expansion plans were developed using a model of uni nodal planning called WASP-IV. The analysis methodology was based on four steps. The first consisted in developing, with model WASP-IV, different expansion plans of the electrical generation system that fulfill the energy demand and certain conditions of the study in which was optimized the additions program of generator units searching the minimal cost of electrical generation. The second step was to calculate the generation costs of each plan for two scenarios of fuel prices, also with model WASP-IV. Later was calculated the diversity index and the accumulated emissions during the expansion and the avoided emission of CO{sub 2} when units of combined cycle that burn natural gas are replaced by nuclear power units. (Author)

  16. Entropy method combined with extreme learning machine method for the short-term photovoltaic power generation forecasting

    International Nuclear Information System (INIS)

    Tang, Pingzhou; Chen, Di; Hou, Yushuo

    2016-01-01

    As the world’s energy problem becomes more severe day by day, photovoltaic power generation has opened a new door for us with no doubt. It will provide an effective solution for this severe energy problem and meet human’s needs for energy if we can apply photovoltaic power generation in real life, Similar to wind power generation, photovoltaic power generation is uncertain. Therefore, the forecast of photovoltaic power generation is very crucial. In this paper, entropy method and extreme learning machine (ELM) method were combined to forecast a short-term photovoltaic power generation. First, entropy method is used to process initial data, train the network through the data after unification, and then forecast electricity generation. Finally, the data results obtained through the entropy method with ELM were compared with that generated through generalized regression neural network (GRNN) and radial basis function neural network (RBF) method. We found that entropy method combining with ELM method possesses higher accuracy and the calculation is faster.

  17. Medium term municipal solid waste generation prediction by autoregressive integrated moving average

    International Nuclear Information System (INIS)

    Younes, Mohammad K.; Nopiah, Z. M.; Basri, Noor Ezlin A.; Basri, Hassan

    2014-01-01

    Generally, solid waste handling and management are performed by municipality or local authority. In most of developing countries, local authorities suffer from serious solid waste management (SWM) problems and insufficient data and strategic planning. Thus it is important to develop robust solid waste generation forecasting model. It helps to proper manage the generated solid waste and to develop future plan based on relatively accurate figures. In Malaysia, solid waste generation rate increases rapidly due to the population growth and new consumption trends that characterize the modern life style. This paper aims to develop monthly solid waste forecasting model using Autoregressive Integrated Moving Average (ARIMA), such model is applicable even though there is lack of data and will help the municipality properly establish the annual service plan. The results show that ARIMA (6,1,0) model predicts monthly municipal solid waste generation with root mean square error equals to 0.0952 and the model forecast residuals are within accepted 95% confident interval

  18. Developing long-term scenario forecasts to support electricity generation investment decisions

    CSIR Research Space (South Africa)

    Koen, Renée

    2014-09-01

    Full Text Available Many decisions regarding capital investment in electricity generation technologies need to be made well in advance, usually when there is still a large amount of uncertainty regarding the favourability of future conditions. There may be uncertainty...

  19. Trading wind generation from short-term probabilistic forecasts of wind power

    DEFF Research Database (Denmark)

    Pinson, Pierre; Chevallier, Christophe; Kariniotakis, Georges

    2007-01-01

    Due to the fluctuating nature of the wind resource, a wind power producer participating in a liberalized electricity market is subject to penalties related to regulation costs. Accurate forecasts of wind generation are therefore paramount for reducing such penalties and thus maximizing revenue......, as well as on modeling of the sensitivity a wind power producer may have to regulation costs. The benefits resulting from the application of these strategies are clearly demonstrated on the test case of the participation of a multi-MW wind farm in the Dutch electricity market over a year....... participation. Such strategies permit to further increase revenues and thus enhance competitiveness of wind generation compared to other forms of dispatchable generation. This paper formulates a general methodology for deriving optimal bidding strategies based on probabilistic forecasts of wind generation...

  20. Medium term municipal solid waste generation prediction by autoregressive integrated moving average

    Science.gov (United States)

    Younes, Mohammad K.; Nopiah, Z. M.; Basri, Noor Ezlin A.; Basri, Hassan

    2014-09-01

    Generally, solid waste handling and management are performed by municipality or local authority. In most of developing countries, local authorities suffer from serious solid waste management (SWM) problems and insufficient data and strategic planning. Thus it is important to develop robust solid waste generation forecasting model. It helps to proper manage the generated solid waste and to develop future plan based on relatively accurate figures. In Malaysia, solid waste generation rate increases rapidly due to the population growth and new consumption trends that characterize the modern life style. This paper aims to develop monthly solid waste forecasting model using Autoregressive Integrated Moving Average (ARIMA), such model is applicable even though there is lack of data and will help the municipality properly establish the annual service plan. The results show that ARIMA (6,1,0) model predicts monthly municipal solid waste generation with root mean square error equals to 0.0952 and the model forecast residuals are within accepted 95% confident interval.

  1. Medium term municipal solid waste generation prediction by autoregressive integrated moving average

    Energy Technology Data Exchange (ETDEWEB)

    Younes, Mohammad K.; Nopiah, Z. M.; Basri, Noor Ezlin A.; Basri, Hassan [Department of Civil and Structural Engineering, Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor (Malaysia)

    2014-09-12

    Generally, solid waste handling and management are performed by municipality or local authority. In most of developing countries, local authorities suffer from serious solid waste management (SWM) problems and insufficient data and strategic planning. Thus it is important to develop robust solid waste generation forecasting model. It helps to proper manage the generated solid waste and to develop future plan based on relatively accurate figures. In Malaysia, solid waste generation rate increases rapidly due to the population growth and new consumption trends that characterize the modern life style. This paper aims to develop monthly solid waste forecasting model using Autoregressive Integrated Moving Average (ARIMA), such model is applicable even though there is lack of data and will help the municipality properly establish the annual service plan. The results show that ARIMA (6,1,0) model predicts monthly municipal solid waste generation with root mean square error equals to 0.0952 and the model forecast residuals are within accepted 95% confident interval.

  2. Aerobic Swim Training Restores Aortic Endothelial Function by Decreasing Superoxide Levels in Spontaneously Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Camila P. Jordão

    Full Text Available OBJECTIVE: We aimed to determine whether aerobic training decreases superoxide levels, increases nitric oxide levels, and improves endothelium-dependent vasodilation in the aortas of spontaneously hypertensive rats. METHODS: Spontaneously hypertensive rats (SHR and Wistar Kyoto rats (WKY were distributed into 2 groups: sedentary (SHRsd and WKYsd, n=10 each and swimming-trained (SHRtr, n=10 and WKYtr, n=10, respectively. The trained group participated in training sessions 5 days/week for 1 h/day with an additional work load of 4% of the animal’s body weight. After a 10-week sedentary or aerobic training period, the rats were euthanized. The thoracic aortas were removed to evaluate the vasodilator response to acetylcholine (10-10 to 10-4 M with or without preincubation with L-NG-nitro-L-arginine methyl ester hydrochloride (L-NAME; 10-4 M in vitro. The aortic tissue was also used to assess the levels of the endothelial nitric oxide synthase and nicotinamide adenine dinucleotide oxidase subunit isoforms 1 and 4 proteins, as well as the superoxide and nitrite contents. Blood pressure was measured using a computerized tail-cuff system. RESULTS: Aerobic training significantly increased the acetylcholine-induced maximum vasodilation observed in the SHRtr group compared with the SHRsd group (85.9±4.3 vs. 71.6±5.2%. Additionally, in the SHRtr group, superoxide levels were significantly decreased, nitric oxide bioavailability was improved, and the levels of the nicotinamide adenine dinucleotide oxidase subunit isoform 4 protein were decreased compared to the SHRsd group. Moreover, after training, the blood pressure of the SHRtr group decreased compared to the SHRsd group. Exercise training had no effect on the blood pressure of the WKYtr group. CONCLUSIONS: In SHR, aerobic swim training decreased vascular superoxide generation by nicotinamide adenine dinucleotide oxidase subunit isoform 4 and increased nitric oxide bioavailability, thereby improving

  3. The potential of the superoxide dismutase inhibitor, diethyldithiocarbamate as an adjuvant to radiotherapy

    International Nuclear Information System (INIS)

    Kent, C.

    1990-10-01

    Oxygen has the potential to be toxic to biologic systems. This toxicity is not due to oxygen itself, but due to the production of oxygen radicals. One of these potentially toxic radicals, superoxide, can be generated as a result of ionizing radiation, and if not adequately removed can proceed to cause cell damage. Superoxide dismutase (SOD) is one of the key enzymes involved in the defence against oxygen toxicity. SOD activity can be inhibited by diethyldithiocarbamate (DDC), a powerful copper chelator. If inhibition of SOD by DDC increases the lifetime and effectiveness of radiation induced superoxide, it follows that the potential exists for DDC to enhance the effect of radiation. DDC is however also a thiol compound, and thus may act as a radioprotector by modifying tissue oxygenation status or by free radical scavenging. The inhibition of superoxide dismutase by diethyldithiocarbamate in order to sensitize tumours to ionizing radiation was studied. The use of DDC as an inhibitor of SOD has however meant that any sensitization resulting from SOD inhibition could be masked by a radioprotective effect by DDC. The inhibition of SOD by DDC was confirmed in a murine rhabdomyosarcoma, and this inhibition can be maintained for up to twenty-four hours after DDC administration. It was shown that DDC could act as both a radiosensitizer and as a radioprotector in the same experiment. The dominant action of DDC was found to be dependent on the time allowed between DDC administration and irradiation. The time modulation effect of DDC was shown in larger tumours, rather than smaller tumours, which could indicate that tumour oxygenation is an important criterion in determining the response to radiation of DDC treated cells. Some caution should be exercised when DDC is put forward as either a radiosensitizer or a radioprotector in the clinic, but DDC may have potential as a thermosensitizer. 37 figs., 23 tabs., 208 refs

  4. Development of source term evaluation method for Korean Next Generation Reactor(III)

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Geon Jae; Park, Jin Baek; Lee, Yeong Il; Song, Min Cheonl; Lee, Ho Jin [Korea Advanced Institue of Science and Technology, Taejon (Korea, Republic of)

    1998-06-15

    This project had investigated irradiation characteristics of MOX fuel method to predict nuclide concentration at primary and secondary coolant using a core containing 100% of all MOX fuel and development of source term evaluation tool. In this study, several prediction methods of source term are evaluated. Detailed contents of this project are : an evaluation of model for nuclear concentration at Reactor Coolant System, evaluation of primary and secondary coolant concentration of reference Nuclear Power Plant using purely MOX fuel, suggestion of source term prediction method of NPP with a core using MOX fuel.

  5. A study on superoxide dismutase activity of some model compounds.

    Science.gov (United States)

    Liao, Z; Liu, W; Liu, J; Jiang, Y; Shi, J; Liu, C

    1994-08-15

    The synthesis and characteristics of a binuclear ligand N,N,N',N'-tetrakis (2'-benzimidazolyl methyl)-1,4-diethylene amino glycol ether (EGTB) and its series of coordination compounds containing copper(II), iron(III), and manganese(II) with and without exogenous bridging ligand which was imidazolate ion (Im-), bipyridine (bpy), or 1,10-phenanthroline (phen) are reported. Depending on the redox potentials by cyclic voltammetry, the coordination compounds can act as catalysts for the dismutation of superoxide radicals (O2-). The detection of the rate constant of the reaction of superoxide ion with nitroblue tetrazolium (NBT) which is inhibited by superoxide dismutase (SOD) and its model compounds of the EGTB system has been performed by a modified illumination method. The rate constants kQ of the catalytic dismutation have been obtained.

  6. QED with minimal and nonminimal couplings: on the quantum generation of Lorentz violating terms in the pure photon sector

    Energy Technology Data Exchange (ETDEWEB)

    Gazzola, G.; Fargnoli, H.G.; Sampaio, Marcos; Nemes, M.C. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Scarpelli, A.P. Baeta [Departamento de Policia Federal (DPF), Sao Paulo, SP (Brazil). Setor Tecnico-Cientifico

    2011-07-01

    In this research we consider a modified version of quantum electrodynamics in four dimensions with the coupling between the photon and the fermion composed by two terms: a nonminimal and the minimal one. There are two interesting aspects in this model. First, gauge invariance is restored by the presence of the minimal coupling. Second, the quantum corrections will allow for the possibility of the generation of a Chern-Simons-like term. The fact that the model is gauge invariant allows for a more complete analysis on the value of both the coefficients of the hypothetical CPT odd and CPT even radiatively generated terms. A question that arises involves a possible violation of some Ward-Takahashi identity when radiative corrections are taken into account. In other words, is there an anomaly in the model? We show that, since conventional QED is gauge invariant, there is no room for a non transversal vacuum polarization tensor in the present model. This is study is to be presented in the following order: first we are to present the model; second we do an analysis on the generation of Lorentz violating terms in the pure gauge sector; third we carry out a calculation on gauge invariance grounds to fix the coefficients of the quantum corrections; and lastly the concluding comments. (author)

  7. QED with minimal and nonminimal couplings: on the quantum generation of Lorentz violating terms in the pure photon sector

    International Nuclear Information System (INIS)

    Gazzola, G.; Fargnoli, H.G.; Sampaio, Marcos; Nemes, M.C.; Scarpelli, A.P. Baeta

    2011-01-01

    In this research we consider a modified version of quantum electrodynamics in four dimensions with the coupling between the photon and the fermion composed by two terms: a nonminimal and the minimal one. There are two interesting aspects in this model. First, gauge invariance is restored by the presence of the minimal coupling. Second, the quantum corrections will allow for the possibility of the generation of a Chern-Simons-like term. The fact that the model is gauge invariant allows for a more complete analysis on the value of both the coefficients of the hypothetical CPT odd and CPT even radiatively generated terms. A question that arises involves a possible violation of some Ward-Takahashi identity when radiative corrections are taken into account. In other words, is there an anomaly in the model? We show that, since conventional QED is gauge invariant, there is no room for a non transversal vacuum polarization tensor in the present model. This is study is to be presented in the following order: first we are to present the model; second we do an analysis on the generation of Lorentz violating terms in the pure gauge sector; third we carry out a calculation on gauge invariance grounds to fix the coefficients of the quantum corrections; and lastly the concluding comments. (author)

  8. An integrated model for long-term power generation planning toward future smart electricity systems

    International Nuclear Information System (INIS)

    Zhang, Qi; Mclellan, Benjamin C.; Tezuka, Tetsuo; Ishihara, Keiichi N.

    2013-01-01

    Highlights: • An integrated model for planning future smart electricity systems was developed. • The model consists of an optimization model and an hour-by-hour simulation model. • The model was applied to Tokyo area, Japan in light of the Fukushima Accident. • Paths to best generation mixes of smart electricity systems were obtained. • Detailed hourly operation patterns in smart electricity systems were obtained. - Abstract: In the present study, an integrated planning model was developed to find economically/environmentally optimized paths toward future smart electricity systems with high level penetration of intermittent renewable energy and new controllable electric devices at the supply and demand sides respectively for regional scale. The integrated model is used to (i) plan the best power generation and capacity mixes to meet future electricity demand subject to various constraints using an optimization model; (ii) obtain detailed operation patterns of power plants and new controllable electric devices using an hour-by-hour simulation model based on the obtained optimized power generation mix. As a case study, the model was applied to power generation planning in the Tokyo area, Japan, out to 2030 in light of the Fukushima Accident. The paths toward best generation mixes of smart electricity systems in 2030 based on fossil fuel, hydro power, nuclear and renewable energy were obtained and the feasibility of the integrated model was proven

  9. The share of nuclear energy in the long-term electricity generation development in Poland

    International Nuclear Information System (INIS)

    Lipko, Krzysztof; Kwiatkowski, Mieczyslaw

    1999-01-01

    Polish power sector is currently undergoing rapid restructuring changes and according to new energy legislation electricity begins to be recognized as other tradable goods. Simultaneously an awareness of interdependencies between power generation expansion and a protection of the environment increases. Presented paper shows these interdependencies against the background of current and future electricity demand satisfying plans determined in Development Office of Polish Power Grid Company in the time range up to the year 2020. Special consideration is given to constraints assumed for power generation sector, relating to emissions of air pollutants, and their influence on possible changes in the mix of fuels used for power generation. In the first part of the paper an applied methodology of drawing up demand satisfying plans consistent with the rules of integrated resource planning (IRP) is described. Accepted macroeconomic assumptions (including these concerning electricity demand forecast) and development constraints related to emissions of air pollutants consistent with national legislation as well as signed international agreements are presented. The set of new generation technologies considered in development studies is described. Two scenarios of the power generation expansion plants developed for a high electricity demand growth are presented. One of them takes into account CO 2 emission constraint while the other neglects it. In the paper it is proved that the above constraint has great influence on the future mix of power plants. In the case when this constraint is taken into account the expansion of electricity generation beyond the year 2010 is based on technologies which do not increase CO 2 emissions, as for example, nuclear power. (author)

  10. Management of main generator condition during long term plant shut down at Higashidori Nuclear Power Station Unit 1

    International Nuclear Information System (INIS)

    Kato, Seiji

    2014-01-01

    Higashidori Nuclear Power Station Unit 1 shut down on February 6, 2011 to start 4th refuel outage. On March 11, 2011, we keep going refuel outage on this moment a large earthquake occurred and tsunami was generated following it which called 'Great East Japan Earthquake'. Refuel outage takes 3 ∼ 5 months normally but Higashidori NPS still keeping shut down over 3 years due to some issues. In this paper, we introduce about management of Main generator condition during long term plant shut down situation in addition to normal plant shut down situation to keep well. (author)

  11. Risk minimization for near-term deployment of the next generation nuclear plant

    International Nuclear Information System (INIS)

    Lommers, L.; Southworth, F.; Riou, B.; Lecomte, M.

    2008-01-01

    The NGNP program is developing the High Temperature Reactor for high efficiency electricity production and high temperature process heat such as direct hydrogen production. AREVA leads one of three vendor teams supporting the NGNP program. AREVA has developed an NGNP concept based on AREVA's ANTARES indirect cycle HTR concept. The ANTARES-based NGNP concept attempts to manage development risk by using a conservative design philosophy which balances performance and risk. Additional risk mitigation for rapid near-term deployment is also considered. Near-term markets may not require the full capability of the indirect cycle very high temperature concept. A steam cycle concept might better serve near-term markets for high temperature steam with reduced technical and schedule risk. (authors)

  12. Dependability of wind energy generators with short-term energy storage.

    Science.gov (United States)

    Sørensen, B

    1976-11-26

    Power fluctuations and power duration curves for wind energy generators, including energy storage facilities of a certain capacity, are compared to those of typical nuclear reactors. A storage system capable of delivering the yearly average power output for about 10 hours already makes the dependability of the wind energy system comparable to that of a typical nuclear plant.

  13. Projection of primary energy in electricity generation with evaluation of demand and supply of energy in the medium-term horizon (2020), long-term (2035) and very long term (2060)

    International Nuclear Information System (INIS)

    Mafra, Olga Y.; Alvim, Carlos Feu; Eidelman, Frida; Guimaraes, Leonam dos Santos

    2013-01-01

    The Global Energy demand and the participation of electricity in scenarios of medium (2020), long (2035) and very long (2060) terms are estimated. It is also evaluated the share of different primary energies in electricity generation and their availability in the country. Three economic scenarios were considered and different hypothesis regarding the participation of nuclear energy were analyzed. (author)

  14. Short-Term Forecasting of Electric Energy Generation for a Photovoltaic System

    Directory of Open Access Journals (Sweden)

    Dinh V.T.

    2018-01-01

    Full Text Available This article presents a short-term forecast of electric energy output of a photovoltaic (PV system towards Tomsk city, Russia climate variations (module temperature and solar irradiance. The system is located at Institute of Non-destructive Testing, Tomsk Polytechnic University. The obtained results show good agreement between actual data and prediction values.

  15. Long-term health effects on the next generation of Ramadan fasting during pregnancy

    NARCIS (Netherlands)

    van Ewijk, R.

    2009-01-01

    Each year, many pregnant women fast from dawn to sunset during the Islamic holy month of Ramadan. Medical theory suggests that this may have negative long-term health effects on their offspring. Building upon the work of Almond and Mazumder (2008), and using Indonesian crosssectional data, I show

  16. Comparative study of different stochastic weather generators for long-term climate data simulation

    Science.gov (United States)

    Climate is one of the single most important factors affecting watershed ecosystems and water resources. The effect of climate variability and change has been studied extensively in some places; in many places, however, assessments are hampered by limited availability of long term continuous climate ...

  17. In vitro generation of long-term repopulating hematopoietic stem cells by fibroblast growth factor-1

    NARCIS (Netherlands)

    de Haan, G; Weersing, E; Dontje, B; van Os, R; Bystrykh, LV; Vellenga, E; Miller, G

    The role of fibroblast growth factors and their receptors (FGFRs) in the regulation of normal hematopoietic stem cells is unknown. Here we show that, in mouse bone marrow, long-term repopulating stem cells are found exclusively in the FGFR(+) cell fraction. During differentiation toward committed

  18. Generation of ecosystem hotspots using short-term cattle corrals in an African savanna

    Science.gov (United States)

    Many rangelands are now being managed for multiple uses, and it is increasingly important to identify livestock management practices that maximize long-term productivity, biodiversity and wildlife conservation. In sub-Saharan Africa, pastoralists and ranchers use temporary thorn-fence corrals (“boma...

  19. Long-term research in Japan: amorphous metals, metal oxide varistors, high-power semiconductors and superconducting generators

    Energy Technology Data Exchange (ETDEWEB)

    Hane, G.J.; Yorozu, M.; Sogabe, T.; Suzuki, S.

    1985-04-01

    The review revealed that significant activity is under way in the research of amorphous metals, but that little fundamental work is being pursued on metal oxide varistors and high-power semiconductors. Also, the investigation of long-term research program plans for superconducting generators reveals that activity is at a low level, pending the recommendations of a study currently being conducted through Japan's Central Electric Power Council.

  20. How to generate spinor representations in any dimension in terms of projection and nilpotent operators

    International Nuclear Information System (INIS)

    Borstnik, N. Mankoc; Nielsen, H.B.

    2002-01-01

    We present a technique to construct a spinor space basis as products of certain nilpotents and projections formed from γ a for which we only need to know that they obey the Clifford algebra. The technique works for all dimensions and signatures. We use this technique to deliver a concrete choice of γ-matrices and Lorentz group generators for (fundamental representations of) spinors in a rather systematic and transparent way. We further develop the formalism by proposing the corresponding graphic presentation of basic states, which offers an easy way to see all the quantum numbers of states with respect to the generators of the Lorentz group, as well as transformation properties of the states under any element of the Clifford algebra

  1. Oxidative stress and superoxide dismutase activity in brain of rats ...

    African Journals Online (AJOL)

    The present study was envisaged to investigate the possible role of oxidative stress in permethrin neurotoxicity and to evaluate the protective effect of superoxide dismutase (SOD) activity in brain homogenates of Wistar rats. Oxidative stress measured as thiobarbituric acid reacting substances (TBARS) was found to ...

  2. Water stress induces overexpression of superoxide dismutases that ...

    African Journals Online (AJOL)

    Water stress is known to induce active oxygen species in plants. The accumulation of these harmful species must be prevented by plants as rapidly as possible to maintain growth and productivity. The aim of this study was to determine the effect of water stress on superoxide dismutase isozymes (SOD, EC 1.15.1.1.) in two ...

  3. Effect of yogic exercise on superoxide dismutase levels in diabetics

    Directory of Open Access Journals (Sweden)

    Mahapure Hemant

    2008-01-01

    Full Text Available Context: Reactive oxygen species are known to aggravate disease progression. To counteract their harmful effects, the body produces various antioxidant enzymes, viz , superoxide dismutase, glutathione reductase etc. Literature reviews revealed that exercises help to enhance antioxidant enzyme systems; hence, yogic exercises may be useful to combat various diseases. Aims: This study aims to record the efficacy of yoga on superoxide dismutase, glycosylated hemoglobin (Hb and fasting blood glucose levels in diabetics. Settings and Design: Forty diabetics aged 40-55 years were assigned to experimental (30 and control (10 groups. The experimental subjects underwent a Yoga program comprising of various Asanas (isometric type exercises and Pranayamas (breathing exercises along with regular anti-diabetic therapy whereas the control group received anti-diabetic therapy only. Methods and Material: Heparinized blood samples were used to determine erythrocyte superoxide dismutase (SOD activity and glycosylated Hb levels and fasting blood specimens collected in fluoride Vacutainers were used for assessing blood glucose. Statistical analysis used: Data were analyzed by using 2 x 2 x 3 Factorial ANOVA followed by Scheffe′s posthoc test. Results: The results revealed that Yogic exercise enhanced the levels of Superoxide dismutase and reduced glycosylated Hb and glucose levels in the experimental group as compared to the control group. Conclusion: The findings conclude that Yogic exercises have enhanced the antioxidant defence mechanism in diabetics by reducing oxidative stress.

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

    International Nuclear Information System (INIS)

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

    2011-01-01

    Unlike superoxide dismutases (SODs), superoxidereductases (SORs) eliminate superoxide anion (O 2 # sm b ullet# - ) 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 # sm b ullet# - with a pH-independent second-order rate constant k 1 = 1.0 x 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.

  5. Spectral quantum fluctuations in a stimulated Raman generator: a description in terms of temporally coherent modes.

    Science.gov (United States)

    Walmsley, I A

    1992-03-15

    The probability density of the single-shot mean Stokes frequency from a linear Raman generator is calculated. It is shown that the fluctuations in the Stokes pulse energy spectrum that arise from the quantum initiation of the Stokes light are reduced in the transient regime of amplification. Also, it appears that saturation of the Raman gain does not reduce the phase fluctuations of the Stokes light below those present in the unsaturated gain (linear) regime.

  6. Long-term record of top-of-atmosphere albedo generated from AVHRR data

    Science.gov (United States)

    Song, Z.

    2017-12-01

    Top-of-Atmosphere (TOA) albedo is a fundamental component of Earth's energy budget. Previously, long-term accurate TOA albedo products did not exist due to the lack of stable broadband observations. With a new albedo estimation methodology based on multispectral observations, TOA albedo since 1981 has been retrieved using data from the Advanced Very High Resolution Radiometer (AVHRR), which provides the longest record of satellite observations across the globe. To develop the long-term TOA albedo record, the instantaneous TOA albedo was calculated by the direct estimation method, which was built on training data pairs from coincident AVHRR TOA reflectance and Moderate Resolution Imaging Spectroradiometer (MODIS) TOA albedo. The instantaneous TOA albedo was then converted to daily mean and monthly mean albedo based on the diurnal curves from geostationary satellites. The TOA albedo results (AVHRR-TAL) were compared with Clouds and the Earth's Radiant Energy System (CERES) flux products for 2007. The monthly mean AVHRR-TAL agreed well with the CERES products, with a root mean square difference (RMSD) of 0.032 and a bias of 0.013. In addition, AVHRR-TAL showed similar seasonal variations to those seen in the CERES products. Further analysis on long-term time series showed good consistency between the two datasets (R2 > 0.95 and relative RMSD < 4%) from 2000 to 2015. Although some calibration issues remain to be solved, our datasets show the potential ability to observe the global TOA albedo from 1981 to the present.

  7. Long-term field test of solar PV power generation using one-axis 3-position sun tracker

    KAUST Repository

    Huang, B.J.

    2011-09-01

    The 1 axis-3 position (1A-3P) sun tracking PV was built and tested to measure the daily and long-term power generation of the solar PV system. A comparative test using a fixed PV and a 1A-3P tracking PV was carried out with two identical stand-alone solar-powered LED lighting systems. The field test in the particular days shows that the 1A-3P tracking PV can generate 35.8% more electricity than the fixed PV in a partly-cloudy weather with daily-total solar irradiation HT=11.7MJ/m2day, or 35.6% in clear weather with HT=18.5MJ/m2day. This indicates that the present 1A-3P tracking PV can perform very close to a dual-axis continuous tracking PV (Kacira et al., 2004). The long-term outdoor test results have shown that the increase of daily power generation of 1A-3P tracking PV increases with increasing daily-total solar irradiation. The increase of monthly-total power generation for 1A-3P sun tracking PV is between 18.5-28.0%. The total power generation increase in the test period from March 1, 2010 to March 31, 2011, is 23.6% in Taipei (an area of low solar energy resource). The long-term performance of the present 1X-3P tracking PV is shown very close to the 1-axis continuous tracking PV in Taiwan (Chang, 2009). If the 1A-3P tracking PV is used in the area of high solar energy resource with yearly-average HT>17MJ/m2day, the increase of total long-term power generation with respect to fixed PV will be higher than 37.5%. This is very close to that of dual-axis continuous tracking PV. The 1A-3P tracker can be easily mounted on the wall of a building. The cost of the whole tracker is about the same as the regular mounting cost of a conventional rooftop PV system. This means that there is no extra cost for 1A-3P PV mounted on buildings. The 1A-3P PV is quite suitable for building-integrated applications. © 2011 Elsevier Ltd.

  8. Mitigating Short-Term Variations of Photovoltaic Generation Using Energy Storage with VOLTTRON

    Science.gov (United States)

    Morrissey, Kevin

    A smart-building communications system performs smoothing on photovoltaic (PV) power generation using a battery energy storage system (BESS). The system runs using VOLTTRON(TM), a multi-agent python-based software platform dedicated to power systems. The VOLTTRON(TM) system designed for this project runs synergistically with the larger University of Washington VOLTTRON(TM) environment, which is designed to operate UW device communications and databases as well as to perform real-time operations for research. One such research algorithm that operates simultaneously with this PV Smoothing System is an energy cost optimization system which optimizes net demand and associated cost throughout a day using the BESS. The PV Smoothing System features an active low-pass filter with an adaptable time constant, as well as adjustable limitations on the output power and accumulated battery energy of the BESS contribution. The system was analyzed using 26 days of PV generation at 1-second resolution. PV smoothing was studied with unconstrained BESS contribution as well as under a broad range of BESS constraints analogous to variable-sized storage. It was determined that a large inverter output power was more important for PV smoothing than a large battery energy capacity. Two methods of selecting the time constant in real time, static and adaptive, are studied for their impact on system performance. It was found that both systems provide a high level of PV smoothing performance, within 8% of the ideal case where the best time constant is known ahead of time. The system was run in real time using VOLTTRON(TM) with BESS limitations of 5 kW/6.5 kWh and an adaptive update period of 7 days. The system behaved as expected given the BESS parameters and time constant selection methods, providing smoothing on the PV generation and updating the time constant periodically using the adaptive time constant selection method.

  9. Complications Associated with Long-Term Disposition of Newly-Generated Transuranic Waste: A National Laboratory Perspective

    International Nuclear Information System (INIS)

    Orchard, B.J.; Harvego, L.A.; Carlson, T.L.; Grant, R.P.

    2009-01-01

    The Idaho National Laboratory (INL) is a multipurpose national laboratory delivering specialized science and engineering solutions for the U.S. Department of Energy (DOE). Sponsorship of INL was formally transferred to the DOE Office of Nuclear Energy, Science and Technology (NE) by Secretary Spencer Abraham in July 2002. The move to NE, and designation as the DOE lead nuclear energy laboratory for reactor technology, supports the nation's expanding nuclear energy initiatives, placing INL at the center of work to develop advanced Generation IV nuclear energy systems; nuclear energy/hydrogen coproduction technology; advanced nuclear energy fuel cycle technologies; and providing national security answers to national infrastructure needs. As a result of the Laboratory's NE mission, INL generates both contact-handled and remote-handled transuranic (TRU) waste from ongoing operations. Generation rates are relatively small and fluctuate based on specific programs and project activities being conducted; however, the Laboratory will continue to generate TRU waste well into the future in association with the NE mission. Currently, plans and capabilities are being established to transfer INL's contact-handled TRU waste to the Advanced Mixed Waste Treatment Plant (AMWTP) for certification and disposal to the Waste Isolation Pilot Plant (WIPP). Remote-handled TRU waste is currently placed in storage at the Materials and Fuels Complex (MFC). In an effort to minimize future liabilities associated with the INL NE mission, INL is evaluating and assessing options for the management and disposition of all its TRU waste on a real-time basis at time of generation. This paper summarizes near-term activities to minimize future re handling of INL's TRU waste, as well as, potential complications associated with the long-term disposition of newly-generated TRU waste. Potential complications impacting the disposition of INL newly-generated TRU waste include, but are not limited to: (1

  10. Superoxide produced in the matrix of mitochondria enhances methylmercury toxicity in human neuroblastoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Mailloux, Ryan J.; Yumvihoze, Emmanuel; Chan, Hing Man, E-mail: laurie.chan@uottawa.ca

    2015-12-15

    The mechanism of intracellular metabolism of methylmercury (MeHg) is not fully known. It has been shown that superoxide (O{sub 2}·{sup −}), the proximal reactive oxygen species (ROS) generated by mitochondria, is responsible for MeHg demethylation. Here, we investigated the impact of different mitochondrial respiratory inhibitors, namely rotenone and antimycin A, on the O{sub 2}·{sup −} mediated degradation of MeHg in human neuroblastoma cells SH-K-SN. We also utilized paraquat (PQ) which generates O{sub 2}·{sup −} in the mitochondrial matrix. We found that the cleavage of the carbon-metal bond in MeHg was highly dependent on the topology of O{sub 2}·{sup −} production by mitochondria. Both rotenone and PQ, which increase O{sub 2}·{sup −} in the mitochondrial matrix at a dose-dependent manner, enhanced the conversion of MeHg to inorganic mercury (iHg). Surprisingly, antimycin A, which prompts emission of O{sub 2}·{sup −} into the intermembrane space, did not have the same effect even though antimycin A induced a dose dependent increase in O{sub 2}·{sup −} emission. Rotenone and PQ also enhanced the toxicity of sub-toxic doses (0.1 μM) MeHg which correlated with the accumulation of iHg in mitochondria and depletion of mitochondrial protein thiols. Taken together, our results demonstrate that MeHg degradation is mediated by mitochondrial O{sub 2}·{sup −}, specifically within the matrix of mitochondria when O{sub 2}·{sup −} is in adequate supply. Our results also show that O{sub 2}·{sup −} amplifies MeHg toxicity specifically through its conversion to iHg and subsequent interaction with protein cysteine thiols (R-SH). The implications of our findings in mercury neurotoxicity are discussed herein. - Highlights: • Superoxide produced in the matrix of mitochondria degrades MeHg. • Superoxide produced in intermembrane space does not degrade MeHg. • Matrix-generated superoxide enhances Hg toxicity by converting MeHg to iHg.

  11. Automated EEG sleep staging in the term-age baby using a generative modelling approach

    Science.gov (United States)

    Pillay, Kirubin; Dereymaeker, Anneleen; Jansen, Katrien; Naulaers, Gunnar; Van Huffel, Sabine; De Vos, Maarten

    2018-06-01

    Objective. We develop a method for automated four-state sleep classification of preterm and term-born babies at term-age of 38-40 weeks postmenstrual age (the age since the last menstrual cycle of the mother) using multichannel electroencephalogram (EEG) recordings. At this critical age, EEG differentiates from broader quiet sleep (QS) and active sleep (AS) stages to four, more complex states, and the quality and timing of this differentiation is indicative of the level of brain development. However, existing methods for automated sleep classification remain focussed only on QS and AS sleep classification. Approach. EEG features were calculated from 16 EEG recordings, in 30 s epochs, and personalized feature scaling used to correct for some of the inter-recording variability, by standardizing each recording’s feature data using its mean and standard deviation. Hidden Markov models (HMMs) and Gaussian mixture models (GMMs) were trained, with the HMM incorporating knowledge of the sleep state transition probabilities. Performance of the GMM and HMM (with and without scaling) were compared, and Cohen’s kappa agreement calculated between the estimates and clinicians’ visual labels. Main results. For four-state classification, the HMM proved superior to the GMM. With the inclusion of personalized feature scaling, mean kappa (±standard deviation) was 0.62 (±0.16) compared to the GMM value of 0.55 (±0.15). Without feature scaling, kappas for the HMM and GMM dropped to 0.56 (±0.18) and 0.51 (±0.15), respectively. Significance. This is the first study to present a successful method for the automated staging of four states in term-age sleep using multichannel EEG. Results suggested a benefit in incorporating transition information using an HMM, and correcting for inter-recording variability through personalized feature scaling. Determining the timing and quality of these states are indicative of developmental delays in both preterm and term-born babies that may

  12. Medium-term generation programming in competitive environments: a new optimisation approach for market equilibrium computing

    International Nuclear Information System (INIS)

    Barquin, J.; Centeno, E.; Reneses, J.

    2004-01-01

    The paper proposes a model to represent medium-term hydro-thermal operation of electrical power systems in deregulated frameworks. The model objective is to compute the oligopolistic market equilibrium point in which each utility maximises its profit, based on other firms' behaviour. This problem is not an optimisation one. The main contribution of the paper is to demonstrate that, nevertheless, under some reasonable assumptions, it can be formulated as an equivalent minimisation problem. A computer program has been coded by using the proposed approach. It is used to compute the market equilibrium of a real-size system. (author)

  13. Analysis of long-term impacts of TRU waste remaining at generator/storage sites for No Action Alternative 2

    International Nuclear Information System (INIS)

    Buck, J.W.; Bagaasen, L.M.; Bergeron, M.P.; Streile, G.P.

    1997-09-01

    This report is a supplement to the Waste Isolation Pilot Plant Disposal-Phase Final Supplemental Environmental Impact Statement (SEIS-II). Described herein are the underlying information, data, and assumptions used to estimate the long-term human-health impacts from exposure to radionuclides and hazardous chemicals in transuranic (TRU) waste remaining at major generator/storage sites after loss of institutional control under No Action Alternative 2. Under No Action Alternative 2, TRU wastes would not be emplaced at the Waste Isolation Pilot Plant (WIPP) but would remain at generator/storage sites in surface or near-surface storage. Waste generated at smaller sites would be consolidated at the major generator/storage sites. Current TRU waste management practices would continue, but newly generated waste would be treated to meet the WIPP waste acceptance criteria. For this alternative, institutional control was assumed to be lost 100 years after the end of the waste generation period, with exposure to radionuclides and hazardous chemicals in the TRU waste possible from direct intrusion and release to the surrounding environment. The potential human-health impacts from exposure to radionuclides and hazardous chemicals in TRU waste were analyzed for two different types of scenarios. Both analyses estimated site-specific, human-health impacts at seven major generator/storage sites: the Hanford Site (Hanford), Idaho National Engineering and Environmental Laboratory (INEEL), Lawrence Livermore National Laboratory (LLNL), Los Alamos National Laboratory (LANL), Oak Ridge National Laboratory (ORNL), Rocky Flats Environmental Technology Site (RFETS), and Savannah River Site (SRS). The analysis focused on these seven sites because 99 % of the estimated TRU waste volume and inventory would remain there under the assumptions of No Action Alternative 2

  14. Super short term forecasting of photovoltaic power generation output in micro grid

    Science.gov (United States)

    Gong, Cheng; Ma, Longfei; Chi, Zhongjun; Zhang, Baoqun; Jiao, Ran; Yang, Bing; Chen, Jianshu; Zeng, Shuang

    2017-01-01

    The prediction model combining data mining and support vector machine (SVM) was built. Which provide information of photovoltaic (PV) power generation output for economic operation and optimal control of micro gird, and which reduce influence of power system from PV fluctuation. Because of the characteristic which output of PV rely on radiation intensity, ambient temperature, cloudiness, etc., so data mining was brought in. This technology can deal with large amounts of historical data and eliminate superfluous data, by using fuzzy classifier of daily type and grey related degree. The model of SVM was built, which can dock with information from data mining. Based on measured data from a small PV station, the prediction model was tested. The numerical example shows that the prediction model is fast and accurate.

  15. Fuzzy possibilistic model for medium-term power generation planning with environmental criteria

    International Nuclear Information System (INIS)

    Muela, E.; Schweickardt, G.; Garces, F.

    2007-01-01

    The aim of this paper is to apply a fuzzy possibilistic model to the power generation planning that includes environmental criteria. Since it is not always meaningful to relate uncertainty to frequency, the proposed approach analyzes the imprecision and ambiguity into the decision making, especially when the system involves human subjectivity. This paper highlights the subjacent differences between fuzzy and possibilistic entities. Additionally, it illustrates the use of fuzzy sets theory and possibility theory for modeling flexibility, and nonprobablistic uncertainty, respectively. The necessity of a new direction for the environmental problem in a power system is outlined, an approach that attempts a greater integral quality of planning instead of searching for a simple optimal solution. This process must be consistent with a wider and more suitable interpretation about both the problem as such and the concept of solution in uncertain situations

  16. Overview of fourth generation reactors. Assessment in terms of safety and radiation protection

    International Nuclear Information System (INIS)

    Couturier, J.; Baudrand, O.; Blanc, D.; Bourgois, T.; Hache, G.; Ivanov, E.; Bonneville, H.; Meignen, R.; Nicaise, G.; Bruna, G.; Clement, B.; Kissane, M.; Monhardt, B.

    2012-01-01

    Based on a systematic analysis of the different concepts of fourth generation nuclear reactors, this report gives an overview of specific aspects regarding safety and radiation protection for six concepts: sodium fast reactors (SFR), gas fast reactors (GFR), lead fast reactors (LFR), molten salt reactors (MSR), very high or high temperature reactors (V/HTR) and supercritical water reactors (SCWR). This assessment is based on different studies and researches performed by the IRSN at an international level. For each reactor concept, the report proposes a presentation of the current status of development and its perspectives, describes the safety aspects which are specific to this concept, identifies and discusses elements for safety analysis, and assesses the concept with respect to the Fukushima accident and IAEA recommendations and predefined themes

  17. Retention time generates short-term phytoplankton blooms in a shallow microtidal subtropical estuary

    Science.gov (United States)

    Odebrecht, Clarisse; Abreu, Paulo C.; Carstensen, Jacob

    2015-09-01

    In this study it was hypothesised that increasing water retention time promotes phytoplankton blooms in the shallow microtidal Patos Lagoon estuary (PLE). This hypothesis was tested using salinity variation as a proxy of water retention time and chlorophyll a for phytoplankton biomass. Submersible sensors fixed at 5 m depth near the mouth of PLE continuously measured water temperature, salinity and pigments fluorescence (calibrated to chlorophyll a) between March 2010 and 12th of December 2011, with some gaps. Salinity variations were used to separate alternating patterns of outflow of lagoon water (salinity 24; 35% of the time). The two transition phases represented a rapid change from lagoon water outflow to marine water inflow and a more gradually declining salinity between the dominating inflow and outflow conditions. During the latter of these, a significant chlorophyll a increase relative to that expected from a linear mixing relationship was observed at intermediate salinities (10-20). The increase in chlorophyll a was positively related to the duration of the prior coastal water inflow in the PLE. Moreover, chlorophyll a increase was significantly higher during austral spring-summer than autumn-winter, probably due to higher light and nutrient availability in the former. Moreover, the retention time process operating on time scales of days influences the long-term phytoplankton variability in this ecosystem. Comparing these results with monthly data from a nearby long-term water quality monitoring station (1993-2011) support the hypothesis that chlorophyll a accumulations occur after marine inflow events, whereas phytoplankton does not accumulate during high water outflow, when the water residence time is short. These results suggest that changing hydrological pattern is the most important mechanism underlying phytoplankton blooms in the PLE.

  18. Modeling Long-term Creep Performance for Welded Nickel-base Superalloy Structures for Power Generation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Chen [GE Global Research, NIskayuna, NY (United States); Gupta, Vipul [GE Global Research, NIskayuna, NY (United States); Huang, Shenyan [GE Global Research, NIskayuna, NY (United States); Soare, Monica [GE Global Research, NIskayuna, NY (United States); Zhao, Pengyang [GE Global Research, NIskayuna, NY (United States); Wang, Yunzhi [GE Global Research, NIskayuna, NY (United States)

    2017-02-28

    The goal of this project is to model long-term creep performance for nickel-base superalloy weldments in high temperature power generation systems. The project uses physics-based modeling methodologies and algorithms for predicting alloy properties in heterogeneous material structures. The modeling methodology will be demonstrated on a gas turbine combustor liner weldment of Haynes 282 precipitate-strengthened nickel-base superalloy. The major developments are: (1) microstructure-property relationships under creep conditions and microstructure characterization (2) modeling inhomogeneous microstructure in superalloy weld (3) modeling mesoscale plastic deformation in superalloy weld and (4) a constitutive creep model that accounts for weld and base metal microstructure and their long term evolution. The developed modeling technology is aimed to provide a more efficient and accurate assessment of a material’s long-term performance compared with current testing and extrapolation methods. This modeling technology will also accelerate development and qualification of new materials in advanced power generation systems. This document is a final technical report for the project, covering efforts conducted from October 2014 to December 2016.

  19. Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy.

    Science.gov (United States)

    Masia, Lorenzo; Frascarelli, Flaminia; Morasso, Pietro; Di Rosa, Giuseppe; Petrarca, Maurizio; Castelli, Enrico; Cappa, Paolo

    2011-05-21

    It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of subjects affected by Cerebral Palsy (CP group, 7 subjects) with a Control group of unimpaired age-matched children. The protocol included a familiarization phase (FA), during which no force was applied, a force field adaptation phase (CF), and a wash-out phase (WO) in which the field was removed. During the CF phase the field was shut down in a number of randomly selected "catch" trials, which were used in order to evaluate the "learning index" for each single subject and the two groups. Lateral deviation, speed and acceleration peaks and average speed were evaluated for each trajectory; a directional analysis was performed in order to inspect the role of the limb's inertial anisotropy in the different experimental phases. During the FA phase the movements of the CP subjects were more curved, displaying greater and variable directional error; over the course of the CF phase both groups showed a decreasing trend in the lateral error and an after-effect at the beginning of the wash-out, but the CP group had a non significant adaptation rate and a lower learning index, suggesting that CP subjects have reduced ability to learn to compensate external force. Moreover, a directional analysis of trajectories confirms that the control group is able to better predict the force field by tuning the kinematic features of the movements along different directions in order to account for the inertial anisotropy of arm. Spatial abnormalities in children affected by cerebral palsy may be related not only to disturbance in

  20. Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Di Rosa Giuseppe

    2011-05-01

    Full Text Available Abstract Background It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. Methods We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of subjects affected by Cerebral Palsy (CP group, 7 subjects with a Control group of unimpaired age-matched children. The protocol included a familiarization phase (FA, during which no force was applied, a force field adaptation phase (CF, and a wash-out phase (WO in which the field was removed. During the CF phase the field was shut down in a number of randomly selected "catch" trials, which were used in order to evaluate the "learning index" for each single subject and the two groups. Lateral deviation, speed and acceleration peaks and average speed were evaluated for each trajectory; a directional analysis was performed in order to inspect the role of the limb's inertial anisotropy in the different experimental phases. Results During the FA phase the movements of the CP subjects were more curved, displaying greater and variable directional error; over the course of the CF phase both groups showed a decreasing trend in the lateral error and an after-effect at the beginning of the wash-out, but the CP group had a non significant adaptation rate and a lower learning index, suggesting that CP subjects have reduced ability to learn to compensate external force. Moreover, a directional analysis of trajectories confirms that the control group is able to better predict the force field by tuning the kinematic features of the movements along different directions in order to account for the inertial anisotropy of arm. Conclusions Spatial abnormalities in children affected

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

    Science.gov (United States)

    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.

  2. High-sensitivity imaging method of singlet oxygen and superoxide anion in photodynamic and sonodynamic actions

    Science.gov (United States)

    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.

  3. Haloperidol versus second-generation antipsychotics in the long-term treatment of schizophrenia.

    Science.gov (United States)

    Buoli, Massimiliano; Kahn, René S; Serati, Marta; Altamura, A Carlo; Cahn, Wiepke

    2016-07-01

    The purpose of the study was to compare antipsychotic monotherapies in terms of time to discontinuation in a sample of schizophrenia patients followed-up for 36 months. Two hundred and twenty schizophrenia patients, treated with antipsychotic monotherapy and followed-up in psychiatric outpatient clinics of Universities of Milan and Utrecht were included in the study. A survival analysis (Kaplan-Meier) of the 36-month follow-up period was performed to compare the single treatment groups. End-point was considered as discontinuation of treatment for recurrence, side effects or non-compliance. Patients treated with haloperidol discontinued more than the other groups (Breslow: risperidone p haloperidol group than in the olanzapine group (p haloperidol group than with olanzapine (p haloperidol. In addition, atypical antipsychotics seem to be more protective against recurrences than haloperidol. However, these results should be cautiously interpreted in the light of potential confounder factors such as duration of illness. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  4. Uncertainties in source term calculations generated by the ORIGEN2 computer code for Hanford Production Reactors

    International Nuclear Information System (INIS)

    Heeb, C.M.

    1991-03-01

    The ORIGEN2 computer code is the primary calculational tool for computing isotopic source terms for the Hanford Environmental Dose Reconstruction (HEDR) Project. The ORIGEN2 code computes the amounts of radionuclides that are created or remain in spent nuclear fuel after neutron irradiation and radioactive decay have occurred as a result of nuclear reactor operation. ORIGEN2 was chosen as the primary code for these calculations because it is widely used and accepted by the nuclear industry, both in the United States and the rest of the world. Its comprehensive library of over 1,600 nuclides includes any possible isotope of interest to the HEDR Project. It is important to evaluate the uncertainties expected from use of ORIGEN2 in the HEDR Project because these uncertainties may have a pivotal impact on the final accuracy and credibility of the results of the project. There are three primary sources of uncertainty in an ORIGEN2 calculation: basic nuclear data uncertainty in neutron cross sections, radioactive decay constants, energy per fission, and fission product yields; calculational uncertainty due to input data; and code uncertainties (i.e., numerical approximations, and neutron spectrum-averaged cross-section values from the code library). 15 refs., 5 figs., 5 tabs

  5. Therapeutic intraspinal stimulation to generate activity and promote long-term recovery

    Directory of Open Access Journals (Sweden)

    Sarah E. Mondello

    2014-02-01

    Full Text Available Neuroprosthetic approaches have tremendous potential for the treatment of injuries to the brain and spinal cord by inducing appropriate neural activity in otherwise disordered circuits. Substantial work has demonstrated that stimulation applied to both the central and peripheral nervous system leads to immediate and in some cases sustained benefits after injury. Here we focus on cervical intraspinal microstimulation (ISMS as a promising method of activating the spinal cord distal to an injury site, either to directly produce movements or more intriguingly to improve subsequent volitional control of the paretic extremities. Incomplete injuries to the spinal cord are the most commonly observed in human patients, and these injuries spare neural tissue bypassing the lesion that could be influenced by neural devices to promote recovery of function. In fact, recent results have demonstrated that therapeutic ISMS leads to modest but sustained improvements in forelimb function after an incomplete spinal cord injury. This therapeutic spinal stimulation may promote long-term recovery of function by providing the necessary electrical activity needed for neuron survival, axon growth, and synaptic stability.

  6. Project finance and its limitations in terms of difficult political and structural horizons - the case of electricity generation

    International Nuclear Information System (INIS)

    Fiancette, Georges; Penz, Philippe

    1994-01-01

    Illustrations are given of the kinds of difficulties attendant on the project financing of electricity generation in some developing countries and former socialist countries of Eastern Europe. There are risks due to the instability of the legal framework because of political considerations and also because the organization and regulation of the electricity supply industry is still being developed. Problems may arise because of the gap between the relatively short term of the repayable debt (10 to 12 years) and the lifetime of a typical project (of the order of 30 years). Project investment is usually entrusted to an independent body which often relies on the local electricity company to operate the power station. In this situation, the two bodies involved cannot mutually insure the risks. Exchange rates generate problems associated with convertibility on the one hand and fluctuations on the other. The particular problems which occur in the project financing of power station restoration are discussed. (UK)

  7. Short term hydroelectric power system scheduling with wind turbine generators using the multi-pass iteration particle swarm optimization approach

    International Nuclear Information System (INIS)

    Lee, T.-Y.

    2008-01-01

    This paper uses multi-pass iteration particle swarm optimization (MIPSO) to solve short term hydroelectric generation scheduling of a power system with wind turbine generators. MIPSO is a new algorithm for solving nonlinear optimal scheduling problems. A new index called iteration best (IB) is incorporated into particle swarm optimization (PSO) to improve solution quality. The concept of multi-pass dynamic programming is applied to modify PSO further and improve computation efficiency. The feasible operational regions of the hydro units and pumped storage plants over the whole scheduling time range must be determined before applying MIPSO to the problem. Wind turbine power generation then shaves the power system load curves. Next, MIPSO calculates hydroelectric generation scheduling. It begins with a coarse time stage and searching space and refines the time interval between two time stages and the search spacing pass by pass (iteration). With the cooperation of agents called particles, the near optimal solution of the scheduling problem can be effectively reached. The effects of wind speed uncertainty were also considered in this paper. The feasibility of the new algorithm is demonstrated by a numerical example, and MIPSO solution quality and computation efficiency are compared to those of other algorithms

  8. Generation of geometrical phases and persistent spin currents in 1-dimensional rings by Lorentz-violating terms

    Energy Technology Data Exchange (ETDEWEB)

    Casana, R.; Ferreira, M.M., E-mail: manojr.ufma@gmail.com; Mouchrek-Santos, V.E.; Silva, Edilberto O.

    2015-06-30

    We have demonstrated that Lorentz-violating terms stemming from the fermion sector of the SME are able to generate geometrical phases on the wave function of electrons confined in 1-dimensional rings, as well as persistent spin currents, in the total absence of electromagnetic fields. We have explicitly evaluated the eigenenergies and eigenspinors of the electrons modified by the Lorentz-violating terms, using them to calculate the dynamic and the Aharonov–Anandan phases in the sequel. The total phase presents a pattern very similar to the Aharonov–Casher phase accumulated by electrons in rings under the action of the Rashba interaction. Finally, the persistent spin current were carried out and used to impose upper bounds on the Lorentz-violating parameters.

  9. Long-term congestion management by investment in gas-turbine generators : a cost-benefit analysis

    International Nuclear Information System (INIS)

    Tuan, L.A.; Bhattacharya, K.

    2007-01-01

    Load management is one of the most important tasks in the operation of an electric power system. Transmission congestion occurs whenever the grid has one or more violations of the physical, operation, or policy constraints under which it normally operates. In a deregulated electricity market, the independent system operator (ISO) must ensure that contracted power transactions are carried out reliably. Several schemes of congestion management run the risk of increasing electricity prices due to the market power of local generators in congested areas. An alternative is to manage congestion through the installation of reserve gas turbine generators which can be brought online to the system within a short time. The use of gas turbines at different buses in the system can enhance the system in ways of transmission relief during emergency events. This paper proposed a framework for the evaluation of long-term investment by the ISO on gas-turbine generators as a tool for providing transmission congestion relief in the dispatch stage based on cost-benefit analysis. The objective of the framework is to optimally decide the locations and sizes of the generators at different buses in the network in order to minimize the total cost of investment of gas turbines and to minimize total system congestion. A bus-wise cost-benefit analysis was carried out by solving the DC optimal power flow (dc-OPF) model. The CIGRE 32-Bus system was used for the case study. It was shown that network overloading can be significantly reduced with the support of gas turbines at selected buses. The long-term decision of the investment on gas-turbine would depend on the opportunity cost of the gas-turbine with respect to the congestion problem. The gas turbines could also reduce the amount of unserved energy during peak load conditions. 11 refs., 4 tabs., 3 figs

  10. Measurement of Antioxidant Activity Towards Superoxide in Natural Waters.

    Directory of Open Access Journals (Sweden)

    D. Whitney King

    2016-11-01

    Full Text Available Antioxidants are a class of molecules that provide a protective function against reactive oxygen species (ROS in biological systems by out competing physiologically important molecules for ROS oxidation. In natural waters, the reactivity of antioxidants gives an estimate of oxidative stress and may determine the reactivity and distribution of reactive oxidants. We present an analytical method to measure antioxidant activity in natural waters through the competition between ascorbic acid, an antioxidant, and MCLA, a chemiluminescent probe for superoxide. A numerical kinetic model of the analytical method has been developed to optimize analytical performance. Measurements of antioxidant concentrations in pure and seawater are possible with detection limits below 0.1 nM. Surface seawater samples collected at solar noon contained over 0.4 nM of antioxidants and exhibited first-order decay with a half-life of 3-7 minutes, consistent with a reactive species capable of scavenging photochemically produced superoxide.

  11. Immobilization of Superoxide Dismutase on Polyelectrolyte-Functionalized Titania Nanosheets.

    Science.gov (United States)

    Rouster, Paul; Pavlovic, Marko; Szilagyi, Istvan

    2018-02-16

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

  12. On the short-term predictability of fully digital chaotic oscillators for pseudo-random number generation

    KAUST Repository

    Radwan, Ahmed Gomaa

    2014-06-18

    This paper presents a digital implementation of a 3rd order chaotic system using the Euler approximation. Short-term predictability is studied in relation to system precision, Euler step size and attractor size and optimal parameters for maximum performance are derived. Defective bits from the native chaotic output are neglected and the remaining pass the NIST SP. 800-22 tests without post-processing. The resulting optimized pseudorandom number generator has throughput up to 17.60 Gbits/s for a 64-bit design experimentally verified on a Xilinx Virtex 4 FPGA with logic utilization less than 1.85%.

  13. A study of the contract terms offered by the regional electricity companies to generators of renewable energy outside the NFFO

    International Nuclear Information System (INIS)

    Williams, N.C.; Limbrick, A.J.

    1996-01-01

    The aim of this study was to review the terms and conditions of contract for the purchase of renewable energy currently offered by the Regional Electricity Companies (RECs) outside the Non-Fossil Fuel Obligation (NFFO), through consultation with electricity generators. It focused on projects contracted under the first and second tranches of the NFFO, and those which have been developed outside this support mechanism (both renewable and fossil-fuelled), but which are characterised by being ''embedded'' in the RECs' distribution networks. (UK)

  14. On the short-term predictability of fully digital chaotic oscillators for pseudo-random number generation

    KAUST Repository

    Radwan, Ahmed Gomaa; Mansingka, Abhinav S.; Salama, Khaled N.; Zidan, Mohammed A.

    2014-01-01

    This paper presents a digital implementation of a 3rd order chaotic system using the Euler approximation. Short-term predictability is studied in relation to system precision, Euler step size and attractor size and optimal parameters for maximum performance are derived. Defective bits from the native chaotic output are neglected and the remaining pass the NIST SP. 800-22 tests without post-processing. The resulting optimized pseudorandom number generator has throughput up to 17.60 Gbits/s for a 64-bit design experimentally verified on a Xilinx Virtex 4 FPGA with logic utilization less than 1.85%.

  15. High glucose impairs superoxide production from isolated blood neutrophils

    DEFF Research Database (Denmark)

    Perner, A; Nielsen, S E; Rask-Madsen, J

    2003-01-01

    Superoxide (O(2)(-)), a key antimicrobial agent in phagocytes, is produced by the activity of NADPH oxidase. High glucose concentrations may, however, impair the production of O(2)(-) through inhibition of glucose-6-phosphate dehydrogenase (G6PD), which catalyzes the formation of NADPH. This study...... measured the acute effects of high glucose or the G6PD inhibitor dehydroepiandrosterone (DHEA) on the production of O(2)(-) from isolated human neutrophils....

  16. Superoxide radical (O2-) reactivity with respect to glutathione

    International Nuclear Information System (INIS)

    Sekaki, A.; Gardes-Albert, M.; Ferradini, C.

    1984-01-01

    Influence of superoxide radicals formed during gamma irradiation of glutathione in aerated aqueous solutions is examined. Solutions are buffered at pH7 and contain sodium formate for capture of H and OH radicals which are transformed in COO - radicals and then O 2 - radicals. G value of glutathione disparition vs glutathione concentration are given with and without enzyme or catalase. Reaction mechanism are interpreted [fr

  17. Effects of low doses of short-term gamma irradiation on growth and development through two generations of Pisum sativum

    Energy Technology Data Exchange (ETDEWEB)

    Zaka, R.; Misset, M.T. [UMR-CNRS 6553 Ecobio, Equipe Evolution des Populations et des Especes, Universite de Rennes 1, Campus de Beaulieu Bat. 14, Rennes Cedex F 35042 (France); Chenal, C. [Laboratoire de Radiobiologie, Universite de Rennes 1, Centre Regional de Lutte contre le Cancer, Rennes Cedex F 35062 (France)

    2004-03-29

    The effects of short-term gamma radiation on pea plants were investigated by exposing 5-day-old seedlings with doses ranging from 0 to 60 Gy, and studying plant growth and development over two generations after irradiation. Doses higher than 6 Gy significantly inhibited the G1 plant growth and productivity, and no seedling survived irradiation with 40 Gy and above. These effects were transmitted and were even more severe in the next generation, G2. Irradiated G1 ({>=}10 Gy) and G2 ({>=}0.4 Gy) plants were significantly smaller than controls. The mean number of pods produced per plant was reduced by at least 20% at all doses in both G1 and G2. In parallel, the mean numbers of ovules and normally developed seeds per pod were significantly reduced after 10 Gy in G1 and after 0.4 Gy in G2, leading to a significant drop in seed production. This effect was correlated with a linear decrease in male fertility linked to abnormal meiosis (tetrads with micronuclei) as a function of doses from 0 to 10 Gy, in G1 and G2 plants. These long-term changes in plant development demonstrate a genomic instability induced by irradiation. However, there were neither quantitative nor qualitative changes in storage proteins in G1 seeds at any of the irradiation doses tested from 0 to 10 Gy.

  18. Effects of low doses of short-term gamma irradiation on growth and development through two generations of Pisum sativum

    International Nuclear Information System (INIS)

    Zaka, R.; Misset, M.T.; Chenal, C.

    2004-01-01

    The effects of short-term gamma radiation on pea plants were investigated by exposing 5-day-old seedlings with doses ranging from 0 to 60 Gy, and studying plant growth and development over two generations after irradiation. Doses higher than 6 Gy significantly inhibited the G1 plant growth and productivity, and no seedling survived irradiation with 40 Gy and above. These effects were transmitted and were even more severe in the next generation, G2. Irradiated G1 (≥10 Gy) and G2 (≥0.4 Gy) plants were significantly smaller than controls. The mean number of pods produced per plant was reduced by at least 20% at all doses in both G1 and G2. In parallel, the mean numbers of ovules and normally developed seeds per pod were significantly reduced after 10 Gy in G1 and after 0.4 Gy in G2, leading to a significant drop in seed production. This effect was correlated with a linear decrease in male fertility linked to abnormal meiosis (tetrads with micronuclei) as a function of doses from 0 to 10 Gy, in G1 and G2 plants. These long-term changes in plant development demonstrate a genomic instability induced by irradiation. However, there were neither quantitative nor qualitative changes in storage proteins in G1 seeds at any of the irradiation doses tested from 0 to 10 Gy

  19. Nitric oxide and superoxide dismutase modulate endothelial progenitor cell function in type 2 diabetes mellitus

    Directory of Open Access Journals (Sweden)

    Brenner Benjamin

    2009-10-01

    Full Text Available Abstract Background The function of endothelial progenitor cells (EPCs, which are key cells in vascular repair, is impaired in diabetes mellitus. Nitric oxide (NO and reactive oxygen species can regulate EPC functions. EPCs tolerate oxidative stress by upregulating superoxide dismutase (SOD, the enzyme that neutralizes superoxide anion (O2-. Therefore, we investigated the roles of NO and SOD in glucose-stressed EPCs. Methods The functions of circulating EPCs from patients with type 2 diabetes were compared to those from healthy individuals. Healthy EPCs were glucose-stressed, and then treated with insulin and/or SOD. We assessed O2- generation, NO production, SOD activity, and their ability to form colonies. Results EPCs from diabetic patients generated more O2-, had higher NAD(PH oxidase and SOD activity, but lower NO bioavailability, and expressed higher mRNA and protein levels of p22-phox, and manganese SOD and copper/zinc SOD than those from the healthy individuals. Plasma glucose and HbA1c levels in the diabetic patients were correlated negatively with the NO production from their EPCs. SOD treatment of glucose-stressed EPCs attenuated O2- generation, restored NO production, and partially restored their ability to form colonies. Insulin treatment of glucose-stressed EPCs increased NO production, but did not change O2- generation and their ability to form colonies. However, their ability to produce NO and to form colonies was fully restored after combined SOD and insulin treatment. Conclusion Our data provide evidence that SOD may play an essential role in EPCs, and emphasize the important role of antioxidant therapy in type 2 diabetic patients.

  20. Nitric oxide and superoxide dismutase modulate endothelial progenitor cell function in type 2 diabetes mellitus.

    Science.gov (United States)

    Hamed, Saher; Brenner, Benjamin; Aharon, Anat; Daoud, Deeb; Roguin, Ariel

    2009-10-30

    The function of endothelial progenitor cells (EPCs), which are key cells in vascular repair, is impaired in diabetes mellitus. Nitric oxide (NO) and reactive oxygen species can regulate EPC functions. EPCs tolerate oxidative stress by upregulating superoxide dismutase (SOD), the enzyme that neutralizes superoxide anion (O2-). Therefore, we investigated the roles of NO and SOD in glucose-stressed EPCs. The functions of circulating EPCs from patients with type 2 diabetes were compared to those from healthy individuals. Healthy EPCs were glucose-stressed, and then treated with insulin and/or SOD. We assessed O2- generation, NO production, SOD activity, and their ability to form colonies. EPCs from diabetic patients generated more O2-, had higher NAD(P)H oxidase and SOD activity, but lower NO bioavailability, and expressed higher mRNA and protein levels of p22-phox, and manganese SOD and copper/zinc SOD than those from the healthy individuals. Plasma glucose and HbA1c levels in the diabetic patients were correlated negatively with the NO production from their EPCs. SOD treatment of glucose-stressed EPCs attenuated O2- generation, restored NO production, and partially restored their ability to form colonies. Insulin treatment of glucose-stressed EPCs increased NO production, but did not change O2- generation and their ability to form colonies. However, their ability to produce NO and to form colonies was fully restored after combined SOD and insulin treatment. Our data provide evidence that SOD may play an essential role in EPCs, and emphasize the important role of antioxidant therapy in type 2 diabetic patients.

  1. Manganese superoxide dismutase (MnSOD catalyzes NO-dependent tyrosine residue nitration

    Directory of Open Access Journals (Sweden)

    SRDJAN STOJANOVIC

    2005-04-01

    Full Text Available The peroxynitrite-induced nitration of manganese superoxide dismutase (MnSOD tyrosine residue, which causes enzyme inactivation, is well established. This led to suggestions that MnSOD nitration and inactivation in vivo, detected in various diseases associated with oxidative stress and overproduction of nitric monoxide (NO, conditions which favor peroxynitrite formation, is also caused by peroxynitrite. However, our previous in vitro study demonstrated that exposure of MnSOD to NO led to NO conversion into nitrosonium (NO+ and nitroxyl (NO– species, which caused enzyme modifications and inactivation. Here it is reported that MnSOD is tyrosine nitrated upon exposure to NO, as well as that MnSOD nitration contributes to inactivation of the enzyme. Collectively, these observations provide a compelling argument supporting the generation of nitrating species in MnSOD exposed to NO and shed a new light on MnSOD tyrosine nitration and inactivation in vivo. This may represent a novel mechanism by which MnSOD protects cell from deleterious effects associated with overproduction of NO. However, extensive MnSOD modification and inactivation associated with prolonged exposure to NO will amplify the toxic effects caused by increased cell superoxide and NO levels.

  2. A Manganese Superoxide Dismutase (SOD2 Gene Polymorphism in Insulin-Dependent Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Flemming Pociot

    1993-01-01

    Full Text Available Interleukin I (lL-I is selectively cytotoxic to the insulin producing beta cell of pancreatic islets. This effect may be due to IL-I induced generation of reactive oxygen species and nitric oxide. Since beta cells contain low amounts of the superoxide radical scavenger enzyme manganese superoxide dismutase (MnSOD, this may leave beta cells more susceptible to IL-I than other cell types. Genetic variation in the MnSOD locus could reflect differences in scavenger potential. We, therefore, studied possible restriction fragment length polymorphisms (RFLPs of this locus in patients with insulin-dependent diabetes mellitus (100M (n= 154 and control individuals (n=178, Taql revealed a double diallelic RFLP in patients as well as in controls. No overall difference in allelic or genotype frequencies were observed between 100M patients and control individuals (p=0.11 and no significant association of any particular RFLP pattern with 100M was found. Structurally polymorphic MnSOD protein variants with altered activities have been reported. If genetic variation results in MnSOD variants with reduced activities, the MnSOD locus may still be a candidate gene for 100M susceptibility. Whether the RFLPs reported in this study reflects differences in gene expression level, protein level and/or specific activity of the protein is yet to be studied.

  3. Effect of Ankaferd Blood Stopper on Skin Superoxide Dismutase and Catalase Activities in Warfarin-Treated Rats.

    Science.gov (United States)

    Aktop, Sertaç; Emekli-Alturfan, Ebru; Gönül, Onur; Göçmen, Gökhan; Garip, Hasan; Yarat, Ayşen; Göker, Kamil

    2017-03-01

    Ankaferd Blood Stopper (ABS) is a new promising local hemostatic agent, and its mechanism on hemostasis has been shown by many studies. However, the effects of ABS on skin superoxide dismutase (SOD) and catalase (CAT) activities have not been investigated before. The aim of this study was to evaluate the effects of this new generation local hemostatic agent on warfarin-treated rats focusing on its the antioxidant potential in short-term soft tissue healing. Twelve systemically warfarin treated (warfarin group) and 12 none treated Wistar Albino rats (control group) were selected for the trial. Rats in the warfarin group were treated intraperitonally with 0.1 mg/kg warfarin, and rats in the control group were given 1 mL/kg saline 3 days earlier to surgical procedure and continued until killing. All rats had incisions on dorsal dermal tissue, which was applied ABS or no hemostatic agent before suturing. Six of each group were killed on day 4, and the other 6 were killed on day 8. Blood and skin samples were taken. Prothrombin time (PT) in blood samples, CAT, and SOD activities in skin samples were determined. Warfarin treatment dose was found to be convenient and warfarin treatment increased the PT levels as expected. Warfarin treatment decreased CAT activity significantly compared to the control group. The ABS treatment significantly increased SOD activities in the warfarin group at the end of the eighth day. Ankaferd Blood Stopper acted positively in short-term tissue healing by increasing SOD activity in warfarin-treated rats. Therefore, ABS may be suggeted as a promoting factor in tissue healing.

  4. Irradiation-resistance conferred by superoxide dismutase: possible adaptive role of a natural polymorphism in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Peng, T.X.; Moya, A.; Ayala, F.J.

    1986-01-01

    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

  5. Superoxide dismutase levels and peak expiratory flow in asthmatic children

    Directory of Open Access Journals (Sweden)

    Arie Kurniasih

    2016-11-01

    Full Text Available Background Asthma is a chronic inflammatory process which involve variety of cells such as inflammatory mediators, reactive oxygen species (ROS, and cytokines. The inflammatory process would be exacerbated in the presence of oxidative stress. Superoxide dismutase (SOD is the first important enzyme to protect the respiratory tract against oxidative stress. The decreased of SOD has a correlation with increased of airway obstruction and bronchospasm. Objective To assess for a correlation between superoxide dismutase (SOD levels and peak expiratory flow, as well as to determine the impact of SOD levels for predicting asthma attacks. Methods We conducted a prospective cohort study at Dr. Sardjito Hospital, Yogyakarta, between February and April 2011 involving asthmatic children aged 5-18 years. Subjects’ serum SOD levels and peak expiratory flow were measured at the same time point. We then performed a prospective study following up on the same subjects to find out if they had a recurrent asthma attack within one month of the tests. We also reassessed their peak expiratory flow one month after blood specimens were obtained. Results Thirty-nine patients were enrolled in this study. There was no significant correlation between SOD level and peak expiratory flow [r=0.289; 95%CI -0.025 to 0.47; P=0.074]. However, older age was significantly associated with higher peak expiratory flow (=0.5; 95%CI 3.10 to 11.57; P=0.01. Lower levels of SOD increased the risk of asthma attacks in a month following the initial measurements (RR=5.5; 95%CI 1.6 to 18.9; P=0.009. Conclusion Superoxide dismutase (SOD level is not significantly associated with peak expiratory flow. However, we find a relationship between older age and higher peak expiratory flow and a relationship between lower SOD levels and risk of asthma attacks within one month following the tests.

  6. A lithium-oxygen battery based on lithium superoxide.

    Science.gov (United States)

    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.

  7. A Bayesian Method for Short-Term Probabilistic Forecasting of Photovoltaic Generation in Smart Grid Operation and Control

    Directory of Open Access Journals (Sweden)

    Gabriella Ferruzzi

    2013-02-01

    Full Text Available A new short-term probabilistic forecasting method is proposed to predict the probability density function of the hourly active power generated by a photovoltaic system. Firstly, the probability density function of the hourly clearness index is forecasted making use of a Bayesian auto regressive time series model; the model takes into account the dependence of the solar radiation on some meteorological variables, such as the cloud cover and humidity. Then, a Monte Carlo simulation procedure is used to evaluate the predictive probability density function of the hourly active power by applying the photovoltaic system model to the random sampling of the clearness index distribution. A numerical application demonstrates the effectiveness and advantages of the proposed forecasting method.

  8. AREVA's toolbox for long-term best performance and reliable operation of nuclear steam generators

    International Nuclear Information System (INIS)

    Drexler, Andreas; Weiss, Steffen; Caris, Neil; Stiepani, Christoph

    2015-01-01

    Long-term integrity and high performance of major plant systems and components are of uppermost importance for the successful operation of any power plant. AREVA's experience gathered with water-steam cycle chemistry treatments in more than 40 years yields the conclusion: Accumulation of corrosion products in SGs may result in local overheating and enrichment of impurities up to critical levels. This can lead to several degradation phenomena of the structural materials of the SGs. Therefore, minimization of corrosion product generation and prevention of deposit accumulation is required. The objective of AREVA's asset management program is to support operators by minimizing corrosion damage and performance losses of water-steam cycle systems and components and thereby to maximize the availability and economic performance of the plant. Such asset management program is in principle a closed cycle process. It is based on control, corrective and preventive measures. The objective of control measure is deriving a widespread assessment of the corrosion status of the steam-water cycle which yields to weak points and identifying the best suited corrective and/or preventive measures. In the subsequent steps appropriate measures which improve the current status or counteract on identified issues are identified and applied. Corrective measures, likes mechanical and/or chemical cleaning are targeting the minimization of negative influence on plant performance caused by corrosion in the steam-water cycle. Complementary to corrective measures are preventive ones, like optimization of pH strategy and AREVA's FFA technology could by applied. They are focusing on the origin of corrosion product generation. AREVA is offering a toolbox for long-term best performance and reliable operation of NPPs. (author)

  9. Low-temperature phase transformation in rubidium and cesium superoxides

    International Nuclear Information System (INIS)

    Alikhanov, R.A.; Toshich, B.S.; Smirnov, L.S.

    1980-01-01

    Crystal structures of rubidium and cesium superoxides which are two interpenetrating lattices of metal ions and oxygen molecule ions reveal a number of phase transformations with temperature decrease. Crystal-phase transformations in CsO 2 are 1-2, 2-3 and low temperature one 3-4 at 378, 190 and 10 K. Low temperature transition is considered as the instability of lattice quadrupoles of oxygen molecule ions to phase transformation of the order-disorder type. Calculated temperatures of low temperature phase transformations in PbO 2 and CsO 2 agree with experimental calculations satisfactory [ru

  10. Radioprotective effects of bacterial superoxide dismutase on mice

    International Nuclear Information System (INIS)

    Hu Tianxi

    1992-01-01

    The radioprotective effects of bacterial superoxide dismutase (b-SOD) on the mice irradiated by 8 Gy γ-ray were investigated. The results showed that when b-SOD was injected before and after irradiation, the survival fraction of mice is increased 50% and 30% respectively. The former treatment could increase the DNA synthesis of the myeloid cells and spleen's lymphocytes, decrease the LPO of tissue homogenates and the hemolysis of erythrocytes significantly. The mechanism that b-SOD can drop the radiation injury of the mice was discussed

  11. Comparing Safety and Efficacy of "Third-Generation" Antiepileptic Drugs: Long-Term Extension and Post-marketing Treatment.

    Science.gov (United States)

    Kwok, Charlotte S; Johnson, Emily L; Krauss, Gregory L

    2017-11-01

    Four "third-generation" antiepileptic drugs (AEDs) were approved for adjunctive treatment of refractory focal onset seizures during the past 10 years. Long-term efficacy and safety of the drugs were demonstrated in large extension studies and in reports of subgroups of patients not studied in pivotal trials. Reviewing extension study and post-marketing outcome series for the four newer AEDs-lacosamide, perampanel, eslicarbazepine acetate and brivaracetam-can guide clinicians in treating and monitoring patients. AED extension studies evaluate treatment retention, drug tolerability, and drug safety during individualized treatment with flexible dosing and thus provide information not available in rigid pivotal trials. Patient retention in the studies ranged from 75 to 80% at 1 year and from 36 to 68% at 2-year treatment intervals. Safety findings were generally similar to those of pivotal trials, with no major safety risks identified and with several specific adverse drug effects, such as hyponatremia, reported. The third-generation AEDs, some through new mechanisms and others with improved tolerability compared to related AEDs, provide new options in efficacy and tolerability.

  12. Long-term effects of trauma: psychosocial functioning of the second and third generation of Holocaust survivors.

    Science.gov (United States)

    Scharf, Miri

    2007-01-01

    The long-term effects of extreme war-related trauma on the second and the third generation of Holocaust survivors (HS) were examined in 88 middle-class families. Differences in functioning between adult offspring of HS (HSO) and a comparison group, as well as the psychosocial functioning of adolescent grandchildren of HS, were studied. Degree of presence of Holocaust in the family was examined in families in which both parents were HSO, either mother or father was HSO, and neither parent was HSO. Mothers' Holocaust background was associated with higher levels of psychological distress and less positive parenting representations. In line with synergic (multiplicative) models of risk, adolescents in families where both parents were HSO perceived their mothers as less accepting and less encouraging independence, and reported less positive self-perceptions than their counterparts. They also perceived their fathers as less accepting and less encouraging independence, showed higher levels of ambivalent attachment style, and according to their peers, demonstrated poorer adjustment during military basic training than their fellow recruits from the one-parent HSO group. Parents and adolescents in the one-parent HSO group functioned similarly to others with no Holocaust background. Parenting variables mediated the association across generations between degree of Holocaust experience in the family of origin of the parents and ambivalent attachment style and self-perception of the adolescents. It is recommended that researchers and clinicians develop awareness of the possible traces of trauma in the second and the third generation despite their sound functioning in their daily lives.

  13. Super long-term scenario of world nuclear power generation and uranium supply and demand until 2030 and further 2100

    International Nuclear Information System (INIS)

    Komiyama, Ryoichi; Kakinoki, Tatsuro

    2007-01-01

    Based on latest nuclear policy and development trend in each country in the world, quantity of nuclear power generation and the uranium supply and demand until 2030 and further 2100 were predicted. As a result, the introduction of nuclear power stations spreads around Asia until 2030. The limitation on the uranium resources clearly does not exist until 2030, but a development period of around 10 years is necessary for exploitation of uranium resources. If timely development investment does not advance, it may invite shortage of uranium supply and promote a remarkable rise of uranium supply price. If the reinforcement of the anti-global warming measure and the diversification of the energy source advance at the super long-term time span called 2100, the world coal power largely decreases and the introduction of the nuclear power enlarges steadily. Introduction of the light water reactor (LWR) extends until 2080 since the fuel uses uranium resources of about 70 year ratio of reserves to production, but quantity of LWR power stations and power generation changes for the decrease due to the limitation of uranium resources after it. On the other hand, sustained expansion of the plutonium utilization by the fuel cycle technology and the introduction of the fast breeder reactor (FBR) advance after 2050. Then the sustained expansion of nuclear power is surely expected to occupy the first share of power generation in 2100. On this account it is necessary to push forward the plutonium use, backend technology and FBR development globally, and Japan is expected to carry a positive role to lead international nuclear energy technology development as a nuclear energy developed nation. (T. Tanaka)

  14. Decarbonization scenarios for the EU and MENA power system: Considering spatial distribution and short term dynamics of renewable generation

    International Nuclear Information System (INIS)

    Haller, Markus; Ludig, Sylvie; Bauer, Nico

    2012-01-01

    We use the multi-scale power system model LIMES-EU + to explore coordinated long term expansion pathways for Renewable Energy (RE) generation, long distance transmission and storage capacities for the power sector of the Europe and Middle East/North Africa (MENA) regions that lead to a low emission power system. We show that ambitious emission reduction targets can be achieved at moderate costs by a nearly complete switch to RE sources until 2050, if transmission and storage capacities are expanded adequately. Limiting transmission capacities to current levels leads to higher storage requirements, higher curtailments, and to an increase in temporal and spatial electricity price variations. Results show an escalation of electricity prices if emission reductions exceed a critical value. Adequate expansion of transmission and storage capacities shift this threshold from 70% to 90% emission reductions in 2050 relative to 2010. - Highlights: ► We present an EU+MENA power system model that considers long term investments and integration of renewables. ► For low emission targets, renewable integration issues lead to escalating electricity prices. ► The feasibility frontier can be pushed by adequate transmission and storage investments. ► The transformation from wind/fossil to wind/solar regime changes integration requirements. ► Low emission targets can be reached without significant interconnections between EU and MENA regions.

  15. Determination of superoxide dismutase mimetic activity in common culinary herbs.

    Science.gov (United States)

    Chohan, Magali; Naughton, Declan P; Opara, Elizabeth I

    2014-01-01

    Under conditions of oxidative stress, the removal of superoxide, a free radical associated with chronic inflammation, is catalysed by superoxide dismutase (SOD). Thus in addition to acting as an antioxidant, SOD may also be utilized as an anti-inflammatory agent. Some plant derived foods have been shown to have SOD mimetic (SODm) activity however it is not known if this activity is possessed by culinary herbs which have previously been shown to possess both antioxidant and anti-inflammatory properties. The aim of the study was to ascertain if the culinary herbs rosemary, sage and thyme possess SODm activity, and to investigate the influence of cooking and digestion on this activity. Transition metal ion content was also determined to establish if it could likely contribute to any SODm activity detected. All extracts of uncooked (U), cooked (C) and cooked and digested (C&D) herbs were shown to possess SODm activity, which was significantly correlated with previously determined antioxidant and anti-inflammatory activities of these herbs. SODm activity was significantly increased following (C) and (C&D) for rosemary and sage only. The impact of (C) and (C&D) on the SODm for thyme may have been influenced by its transition metal ion content. SODm activity may contribute to the herbs' antioxidant and anti-inflammatory activities however the source and significance of this activity need to be established.

  16. Physical and chemical stability of different formulations with superoxide dismutase.

    Science.gov (United States)

    Di Mambro, V M; Campos, P M B G Maia; Fonseca, M J V

    2004-10-01

    Topical formulations with superoxide dismutase (SOD), a scavenger of superoxide radicals, have proved to be effective against some skin diseases. Nevertheless, formulations with proteins are susceptible to both chemical and physical instability. Three different formulations (anionic and non-ionic gel and emulsion) were developed and supplemented with SOD in order to determine the most stable formulation that would maintain SOD activity. Physical stability was evaluated by assessing the rheological behavior of the formulations stored at room temperature, 37 and 45 degrees C. Chemical stability was evaluated by the measurement of enzymatic activity in the formulations stored at room temperature and at 45 degrees C. Formulations showed a flow index less than one, characterizing pseudoplastic behavior. There was no significant difference in initial values of flow index, tixotropy or minimum apparent viscosity. Neither gel showed significant changes in minimum apparent viscosity concerning storage time or temperature, as well, SOD presence and its activity. The emulsion showed decreased viscosity by the 28th day, but no significant changes concerning storage temperature or SOD presence, although it showed a decreased activity. The addition of SOD to the formulations studied did not affect their physical stability but gel formulations seem to be better bases for enzyme addition.

  17. Dark production of extracellular superoxide by the coral Porites astreoides and representative symbionts

    Directory of Open Access Journals (Sweden)

    Tong Zhang

    2016-11-01

    Full Text Available The reactive oxygen species (ROS superoxide has been implicated in both beneficial and detrimental processes in coral biology, ranging from pathogenic disease resistance to coral bleaching. Despite the critical role of ROS in coral health, there is a distinct lack of ROS measurements and thus an incomplete understanding of underpinning ROS sources and production mechanisms within coral systems. Here, we quantified in situ extracellular superoxide concentrations at the surfaces of aquaria-hosted Porites astreoides during a diel cycle. High concentrations of superoxide (~10’s of nM were present at coral surfaces, and these levels did not change significantly as a function of time of day. These results indicate that the coral holobiont produces extracellular superoxide in the dark, independent of photosynthesis. As a short-lived anion at physiological pH, superoxide has a limited ability to cross intact biological membranes. Further, removing surface mucus layers from the P. astreoides colonies did not impact external superoxide concentrations. We therefore attribute external superoxide derived from the coral holobiont under these conditions to the activity of the coral host epithelium, rather than mucus-derived epibionts or internal sources such as endosymbionts (e.g., Symbiodinium. However, endosymbionts likely contribute to internal ROS levels via extracellular superoxide production. Indeed, common coral symbionts, including multiple strains of Symbiodinium (clades A to D and the bacterium Endozoicomonas montiporae LMG 24815, produced extracellular superoxide in the dark and at low light levels. Further, representative P. astreoides symbionts, Symbiodinium CCMP2456 (clade A and E. montiporae, produced similar concentrations of superoxide alone and in combination with each other, in the dark and low light, and regardless of time of day. Overall, these results indicate that healthy, non-stressed P. astreoides and representative symbionts produce

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

    Science.gov (United States)

    Hérouart, D; Van Montagu, M; Inzé, D

    1994-03-01

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

  19. Short-term hydro generation scheduling of Three Gorges–Gezhouba cascaded hydropower plants using hybrid MACS-ADE approach

    International Nuclear Information System (INIS)

    Mo, Li; Lu, Peng; Wang, Chao; Zhou, Jianzhong

    2013-01-01

    Highlights: • MACS and ADE algorithms are hybridized as MACS-ADE method for solving STHGS problem. • An adaptive mutation is integrated into the proposed algorithm to avoid premature convergence. • MACS and ADE are run in parallel in search of better solution. • Several effective heuristic strategies are designed for dealing with various constraints of STHGS problem. - Abstract: Short-term hydro generation scheduling (STHGS) aims at determining optimal hydro generation scheduling to obtain minimum water consumption for one day or week while meeting various system constraints. In this paper, the STHGS problem is decomposed into two sub-problems: (i) unit commitment (UC) sub-problem; (ii) economic load dispatch (ELD) sub-problem. Then, we present a hybrid algorithm based on multi ant colony system (MACS) and differential evolution (DE) for solving the STHGS problem. First, MACS is used for dealing with UC sub-problem. A set of cooperating ant colonies cooperate to choose the unit state over the scheduled time horizon. Then, the adaptive differential evolution (ADE) is used to solve ELD sub-problem. MACS and ADE are run in parallel with adjusting their solutions in search of a better solution. Meanwhile, local and global pheromone updating rules in MACS and adaptive dynamic parameter adjusting strategy in DE are applied for enhancing the search ability of MACS-ADE. Finally, the proposed method is implemented to solve STHGS problem of Three Gorges–Gezhouba cascaded hydropower plants to verify the feasibility and effectiveness. Compared with other established methods, the simulation results reveal that the proposed MACS-ADE approach has the best convergence property, computational efficiency with less water consumption

  20. Microarray analysis of gene expression patterns of high lycopene tomato generated from seeds after long-term space flight

    Science.gov (United States)

    Lu, Jinying; Ren, Chunxiao; Pan, Yi; Nechitailo, Galina S.; Liu, Min

    Lycopene content is a most vital trait of tomatoes due to the role of lycopene in reducing the risk of some kinds of cancers. In this experiment, we gained a high lycopene (hl) tomato (named HY-2), after seven generations of self-cross selection, from seeds Russian MNP-1 carried in Russia MIR space station for six years. HPLC result showed that the lycopene content was 1.6 times more than that in Russian MNP-1 (the wild type). Microarray analysis presented the general profile of differential expressed genes at the tomato developmental stage of 7DPB (days post breaker). One hundred and forty three differential expression genes were identified according to the following criterion: the average changes were no less than 1.5 folds with q-value (similar to FDR) less than 0.05 or changes were no less than 1.5 folds in all three biological replications. Most of the differential expressed genes were mainly involved in metabolism, response to stimulus, biosynthesis, development and regulation. Particularly, we discussed the genes involved in protein metabolism, response to unfolded protein, carotenoid biosynthesis and photosynthesis that might be related to the fruit development and the accumulation of lycopene. What's more, we conducted QRT-PCR validation of five key genes (Fps, CrtL-b, CrtR-b, Zep and Nxs) in the lycopene biosynthesis pathway through time courses and that provided the direct molecular evidence for the hl phenotype. Our results demonstrate that long-term space flight, as a rarely used tool, can positively cause some beneficial mutations in the seeds and thus to help to generate a high quality variety, combined with ground selections.

  1. Second-generation immigrant children: health prevention for a new population in terms of vaccination coverage and health assessment.

    Science.gov (United States)

    Ferrara, Pietro; Zenzeri, Letizia; Fabrizio, Giovanna C; Gatto, Antonio; Pio, Liberatore; Gargiullo, Luisa; Ianniello, Francesca; Valentini, Piero; Ranno, Orazio

    2016-04-01

    In recent years the total number of foreigners taking up residence in Italy is increasing: the number of children born in Italy to foreign parents currently account for 15% of all babies born in the country. This population is generally referred to as "second-generation immigrants". We evaluated the health conditions of this particular population by investigating the vaccination coverage and auxological data in a group of foreign children living in a foster care setting and by comparing them to those regarding a group of foreign children living with their own parents. This study was conducted in a foster care association in Rome. The Pediatric Unit of "A. Gemelli" Hospital, Rome, provided all data for comparison. Two groups of children (group 1: 60 children from a foster care association; group 2: 91 children living with their parents; group 3: 112 healthy controls) with similar characteristics were taken into consideration. There were statistical differences between groups: the administration rate of hexavalent vaccine was significantly higher in group 2 than in group 1 (84.6% vs. 65.0%) (P0.05), although the administration rate of serogroup C meningococcal vaccine was lower in group 1 (10/60; 16.7%) compared to group 2 (17/91; 18.7%) (P>0.05). As for auxological parameters, there were no statistical differences between groups. The data presented in this study seem to suggest the need for a special health programme to be promoted by the Italian National Health System in order to address the needs of the particular risk group of second-generation immigrant children. Vaccination coverage should be especially boosted, and pediatricians should have a key role in terms of awareness raising and education of immigrant families.

  2. Applying a new computer-aided detection scheme generated imaging marker to predict short-term breast cancer risk

    Science.gov (United States)

    Mirniaharikandehei, Seyedehnafiseh; Hollingsworth, Alan B.; Patel, Bhavika; Heidari, Morteza; Liu, Hong; Zheng, Bin

    2018-05-01

    This study aims to investigate the feasibility of identifying a new quantitative imaging marker based on false-positives generated by a computer-aided detection (CAD) scheme to help predict short-term breast cancer risk. An image dataset including four view mammograms acquired from 1044 women was retrospectively assembled. All mammograms were originally interpreted as negative by radiologists. In the next subsequent mammography screening, 402 women were diagnosed with breast cancer and 642 remained negative. An existing CAD scheme was applied ‘as is’ to process each image. From CAD-generated results, four detection features including the total number of (1) initial detection seeds and (2) the final detected false-positive regions, (3) average and (4) sum of detection scores, were computed from each image. Then, by combining the features computed from two bilateral images of left and right breasts from either craniocaudal or mediolateral oblique view, two logistic regression models were trained and tested using a leave-one-case-out cross-validation method to predict the likelihood of each testing case being positive in the next subsequent screening. The new prediction model yielded the maximum prediction accuracy with an area under a ROC curve of AUC  =  0.65  ±  0.017 and the maximum adjusted odds ratio of 4.49 with a 95% confidence interval of (2.95, 6.83). The results also showed an increasing trend in the adjusted odds ratio and risk prediction scores (p  breast cancer risk.

  3. Mid-term outcomes of the Absorb BVS versus second-generation DES: A systematic review and meta-analysis.

    Directory of Open Access Journals (Sweden)

    Cordula M Felix

    Full Text Available Bioresorbable Vascular Scaffolds (BVS were introduced to overcome some of the limitations of drug-eluting stent (DES for PCI. Data regarding the clinical outcomes of the BVS versus DES beyond 2 years are emerging.To study mid-term outcomes.We searched online databases (PubMed/Medline, Embase, CENTRAL, several websites, meeting presentations and scientific session abstracts until August 8th, 2017 for studies comparing Absorb BVS with second-generation DES. The primary outcome was target lesion failure (TLF. Secondary outcomes were all-cause mortality, myocardial infarction, target lesion revascularization (TLR and definite/probable device thrombosis. Odds ratios (ORs with 95% confidence intervals (CIs were derived using a random effects model.Ten studies, seven randomized controlled trials and three propensity-matched observational studies, with a total of 7320 patients (BVS n = 4007; DES n = 3313 and a median follow-up duration of 30.5 months, were included. Risk of TLF was increased for BVS-treated patients (OR 1.34 [95% CI: 1.12-1.60], p = 0.001, I2 = 0%. This was also the case for all myocardial infarction (1.58 [95% CI: 1.27-1.96], p1 year device thrombosis was 6.10 [95% CI: 1.40-26.65], p = 0.02.At mid-term follow-up, BVS was associated with an increased risk of TLF, MI, TLR and definite/probable device thrombosis, but this did not result in an increased risk of all-cause mortality.

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

    Science.gov (United States)

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

    2015-01-01

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

  5. Neuronal uptake and intracellular superoxide scavenging of a fullerene (C60)-poly(2-oxazoline)s nanoformulation

    KAUST Repository

    Tong, Jing

    2011-05-01

    Fullerene, the third allotrope of carbon, has been referred to as a "radical sponge" because of its powerful radical scavenging activities. However, the hydrophobicity and toxicity associated with fullerene limits its application as a therapeutic antioxidant. In the present study, we sought to overcome these limitations by generating water-soluble nanoformulations of fullerene (C(60)). Fullerene (C(60)) was formulated with poly(N-vinyl pyrrolidine) (PVP) or poly(2-alkyl-2-oxazoline)s (POx) homopolymer and random copolymer to form nano-complexes. These C(60)-polymer complexes were characterized by UV-vis spectroscopy, infrared spectroscopy (IR), dynamic light scattering (DLS), atomic force microscopy (AFM) and transmission electron microscopy (TEM). Cellular uptake and intracellular distribution of the selected formulations in catecholaminergic (CATH.a) neurons were examined by UV-vis spectroscopy, immunofluorescence and immunogold labeling. Electron paramagnetic resonance (EPR) spectroscopy was used to determine the ability of these C(60)-polymer complexes to scavenge superoxide. Their cytotoxicity was evaluated in three different cell lines. C(60)-POx and C(60)-PVP complexes exhibited similar physicochemical properties and antioxidant activities. C(60)-poly(2-ethyl-2-oxazoline) (PEtOx) complex, but not C(60)-PVP complex, were efficiently taken up by CATH.a neurons and attenuated the increase in intra-neuronal superoxide induced by angiotensin II (Ang II) stimulation. These results show that C(60)-POx complexes are non-toxic, neuronal cell permeable, superoxide scavenging antioxidants that might be promising candidates for the treatment of brain-related diseases associated with increased levels of superoxide.

  6. Nitric oxide and superoxide anion production in monocytes from children exposed to arsenic and lead in region Lagunera, Mexico

    International Nuclear Information System (INIS)

    Pineda-Zavaleta, Ana Patricia; Garcia-Vargas, Gonzalo; Borja-Aburto, Victor H.; Acosta-Saavedra, Leonor C.; Vera Aguilar, Eunice; Gomez-Munoz, Aristides; Cebrian, Mariano E.; Calderon-Aranda, Emma S.

    2004-01-01

    We evaluated in Mexican children environmentally exposed to arsenic and lead monocyte nitric oxide (NO) and superoxide anion production in response to direct activation with interferon-γ (IFN-γ) + lipopolysaccharide (LPS). The integrity of Th1-regulated cellular immune response when monocytes were indirectly activated was also evaluated. Most children lived near a primary lead smelter. Lead and arsenic contamination in soil and dust by far exceeded background levels. As levels in water were between 10 and 30 ppb. Most children (93%) had urinary arsenic (AsU) concentrations above 50 μg/l (range 16.75-465.75) and 65% had lead blood levels (PbB) above 10 μg/dl (range 3.47-49.19). Multivariate analyses showed that NO production in monocytes activated indirectly was negatively associated with both PbB and AsU. Superoxide production in directly activated monocytes was negatively associated with AsU but positively associated with PbB. The models including the interaction term for AsU and PbB suggested the possibility of a negative interaction for NO production and a positive interaction for superoxide. There were indications of differential gender-based associations, NO production in indirectly activated monocytes obtained from girls was negatively associated with AsU but not with PbB. Superoxide production was positively associated with PbB in both directly and indirectly activated monocytes from boys but the latter was negatively associated with AsU. These effects are consistent with immune system abnormalities observed in human populations exposed to Pb or As. Further studies in larger populations are required to characterize As and Pb interactions and the mechanism(s) underlying the observed effects

  7. Non-smooth optimization methods for large-scale problems: applications to mid-term power generation planning

    International Nuclear Information System (INIS)

    Emiel, G.

    2008-01-01

    evaluated only a subset of the dual local sub-functions, instead of all of them. This type of incremental approach has already been applied for sub-gradient algorithms and the reported computational results are promising. In chapter 4, we use instead a specialized variant of bundle methods known by their stability and precision. We give numerical illustrations for the EDF's mid-term generation planning problem. In chapter 5, we focus on this specific problem. The French power mix includes hydraulic, nuclear, and classical thermal power plants, with each generation unit having its own technical constraints. For an horizon of one to three years, the generation planning problem is a large scale stochastic program, un-tractable with a direct frontal approach. We will present a software using Lagrangian decomposition on a scenario tree to tackle this problem. The dual function is maximized using a proximal bundle method. As a byproduct of our work we proposed some improvements of the algorithms to fasten and stabilize the resolution process and extract useful informations regarding the primal solutions. We also developed a heuristical valuation of water and nuclear resources. (author)

  8. Superoxide scavenging activity of pirfenidone-iron complex

    International Nuclear Information System (INIS)

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

    2008-01-01

    Pirfenidone (PFD) is focused on a new anti-fibrotic drug, which can minimize lung fibrosis etc. We evaluated the superoxide (O 2 ·- ) 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 2 ·- produced by xanthine oxidase/hypoxanthine without inhibiting the enzyme activity. Thirdly, it also reduced the amount of O 2 ·- released from phorbor ester-stimulated human neutrophils. PFD alone showed few such effects. These results suggest the possibility that the O 2 ·- scavenging effect of the PFD-iron complex contributes to the anti-fibrotic action of PFD used for treating idiopathic pulmonary fibrosis

  9. Superoxide dismutase amplifies organismal sensitivity to ionizing radiation

    International Nuclear Information System (INIS)

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

    1989-01-01

    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

  10. Computing Stability Effects of Mutations in Human Superoxide Dismutase 1

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2014-01-01

    Protein stability is affected in several diseases and is of substantial interest in efforts to correlate genotypes to phenotypes. Superoxide dismutase 1 (SOD1) is a suitable test case for such correlations due to its abundance, stability, available crystal structures and thermochemical data......, and physiological importance. In this work, stability changes of SOD1 mutations were computed with five methods, CUPSAT, I-Mutant2.0, I-Mutant3.0, PoPMuSiC, and SDM, with emphasis on structural sensitivity as a potential issue in structure-based protein calculation. The large correlation between experimental...... literature data of SOD1 dimers and monomers (r = 0.82) suggests that mutations in separate protein monomers are mostly additive. PoPMuSiC was most accurate (typical MAE ∼ 1 kcal/mol, r ∼ 0.5). The relative performance of the methods was not very structure-dependent, and the more accurate methods also...

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

    International Nuclear Information System (INIS)

    Piacham, Theeraphon; Isarankura-Na-Ayudhya, Chartchalerm; Nantasenamat, Chanin; Yainoy, Sakda; Ye Lei; Buelow, Leif; Prachayasittikul, Virapong

    2006-01-01

    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

  12. Reduced superoxide dismutase activity in xeroderma pigmentosum fibroblasts

    International Nuclear Information System (INIS)

    Nishigori, C.; Miyachi, Y.; Imamura, S.; Takebe, H.

    1989-01-01

    This study was performed in order to assess the possible protective effect of superoxide dismutase (SOD) on ultraviolet (UV) damage in xeroderma pigmentosum (XP) fibroblasts. SOD activity in fibroblasts originating from seven xeroderma pigmentosum (XP) patients was significantly lower than that in normal cells (p less than 0.005). Average SOD activity in XP cells belonging to complementation group A was 3.68 +/- 0.54 (n = 7) and that in normal human cells was 5.79 +/- 1.59 (n = 6). Addition of SOD before and during UV irradiation (UVB and UVC) to the cells caused no change in the amount of unscheduled DNA synthesis and UV survival. A possible involvement of reduced SOD in XP and a possible protective effect by SOD on UV damage is discussed

  13. The study of the mechanism of arsenite toxicity in respiration-deficient cells reveals that NADPH oxidase-derived superoxide promotes the same downstream events mediated by mitochondrial superoxide in respiration-proficient cells

    Energy Technology Data Exchange (ETDEWEB)

    Guidarelli, Andrea; Fiorani, Mara; Carloni, Silvia; Cerioni, Liana; Balduini, Walter; Cantoni, Orazio, E-mail: orazio.cantoni@uniurb.it

    2016-09-15

    We herein report the results from a comparative study of arsenite toxicity in respiration-proficient (RP) and -deficient (RD) U937 cells. An initial characterization of these cells led to the demonstration that the respiration-deficient phenotype is not associated with apparent changes in mitochondrial mass and membrane potential. In addition, similar levels of superoxide (O{sub 2}{sup .-}) were generated by RP and RD cells in response to stimuli specifically triggering respiratory chain-independent mitochondrial mechanisms or extramitochondrial, NADPH-oxidase dependent, mechanisms. At the concentration of 2.5 μM, arsenite elicited selective formation of O{sub 2}{sup .-} in the respiratory chain of RP cells, with hardly any contribution of the above mechanisms. Under these conditions, O{sub 2}{sup .-} triggered downstream events leading to endoplasmic reticulum (ER) stress, autophagy and apoptosis. RD cells challenged with similar levels of arsenite failed to generate O{sub 2}{sup .-} because of the lack of a functional respiratory chain and were therefore resistant to the toxic effects mediated by the metalloid. Their resistance, however, was lost after exposure to four fold greater concentrations of arsenite, coincidentally with the release of O{sub 2}{sup .-} mediated by NADPH oxidase. Interestingly, extramitochondrial O{sub 2}{sup .-} triggered the same downstream events and an identical mode of death previously observed in RP cells. Taken together, the results obtained in this study indicate that arsenite toxicity is strictly dependent on O{sub 2}{sup .-} availability that, regardless of whether generated in the mitochondrial or extramitochondrial compartments, triggers similar downstream events leading to ER stress, autophagy and apoptosis. - Highlights: • Mitochondrial superoxide mediates arsenite toxicity in respiration-proficient cells. • NADPH-derived superoxide mediates arsenite toxicity in respiration-deficient cells. • Arsenite causes apoptosis

  14. Increased superoxide accumulation in pyruvate dehydrogenase complex deficient fibroblasts.

    Science.gov (United States)

    Glushakova, Lyudmyla G; Judge, Sharon; Cruz, Alex; Pourang, Deena; Mathews, Clayton E; Stacpoole, Peter W

    2011-11-01

    The pyruvate dehydrogenase complex (PDC) oxidizes pyruvate to acetyl CoA and is critically important in maintaining normal cellular energy homeostasis. Loss-of-function mutations in PDC give rise to congenital lactic acidosis and to progressive cellular energy failure. However, the subsequent biochemical consequences of PDC deficiency that may contribute to the clinical manifestations of the disorder are poorly understood. We postulated that altered flux through PDC would disrupt mitochondrial electron transport, resulting in oxidative stress. Compared to cells from 4 healthy subjects, primary cultures of skin fibroblasts from 9 patients with variable mutations in the gene encoding the alpha subunit (E1α) of pyruvate dehydrogenase (PDA1) demonstrated reduced growth and viability. Superoxide (O(2)(.-)) from the Qo site of complex III of the electron transport chain accumulated in these cells and was associated with decreased activity of manganese superoxide dismutase. The expression of uncoupling protein 2 was also decreased in patient cells, but there were no significant changes in the expression of cellular markers of protein or DNA oxidative damage. The expression of hypoxia transcription factor 1 alpha (HIF1α) also increased in PDC deficient fibroblasts. We conclude that PDC deficiency is associated with an increase in O(2)(.-) accumulation coupled to a decrease in mechanisms responsible for its removal. Increased HIF1α expression may contribute to the increase in glycolytic flux and lactate production in PDC deficiency and, by trans-activating pyruvate dehydrogenase kinase, may further suppress residual PDC activity through phosphorylation of the E1α subunit. Copyright © 2011 Elsevier Inc. All rights reserved.

  15. Co-Immobilization of Superoxide Dismutase with Catalase on Soft Microparticles Formed by Self-Assembly of Amphiphilic Poly(Aspartic Acid

    Directory of Open Access Journals (Sweden)

    Siyu Mao

    2017-07-01

    Full Text Available Through genetic engineering technology, catalase (CAT and superoxide dismutase (SOD have been separately fused to an elastin-like polypeptide (ELP. Thus, the enzymes can be purified through phase transition. Hexadecylamine-modified poly(aspartic acid (HPASP is able to self-assemble, forming soft microparticles. The HPASP microparticles were used to co-immobilize SOD-ELP and CAT-ELP through amidation reaction. Circular dichroism (CD confirmed that the secondary structures of the co-immobilized enzymes have been preserved. Fluorescence spectra showed that the co-immobilized enzymes exhibited a higher stability than the free enzymes. Dismutation of superoxide by superoxide dismutase (SOD generates hydrogen peroxide. By using the co-immobilized enzymes (SOD-ELP/CAT-ELP@HPASP, the generated hydrogen peroxide of SOD-ELP can be decomposed in situ by CAT-ELP. Activity assay results demonstrated that the superoxide anion (•O2− scavenging ability is 63.15 ± 0.75% for SOD-ELP/CAT-ELP@HPASP. The advantages of the approach of enzyme co-immobilization include the fact that the soft support HPASP itself is a polypeptide in nature, the stability of immobilized enzymes is improved, and a high activity has been achieved. Potentially SOD-ELP/CAT-ELP@HPASP can be applied in the cosmetic industry.

  16. Zinc-Dependent Protection of Tobacco and Rice Cells From Aluminum-Induced Superoxide-Mediated Cytotoxicity

    Science.gov (United States)

    Lin, Cun; Hara, Ayaka; Comparini, Diego; Bouteau, François; Kawano, Tomonori

    2015-01-01

    Al3+ toxicity in growing plants is considered as one of the major factors limiting the production of crops on acidic soils worldwide. In the last 15 years, it has been proposed that Al3+ toxicity are mediated with distortion of the cellular signaling mechanisms such as calcium signaling pathways, and production of cytotoxic reactive oxygen species (ROS) causing oxidative damages. On the other hand, zinc is normally present in plants at high concentrations and its deficiency is one of the most widespread micronutrient deficiencies in plants. Earlier studies suggested that lack of zinc often results in ROS-mediated oxidative damage to plant cells. Previously, inhibitory action of Zn2+ against lanthanide-induced superoxide generation in tobacco cells have been reported, suggesting that Zn2+ interferes with the cation-induced ROS production via stimulation of NADPH oxidase. In the present study, the effect of Zn2+ on Al3+-induced superoxide generation in the cell suspension cultures of tobacco (Nicotiana tabacum L., cell-line, BY-2) and rice (Oryza sativa L., cv. Nipponbare), was examined. The Zn2+-dependent inhibition of the Al3+-induced oxidative burst was observed in both model cells selected from the monocots and dicots (rice and tobacco), suggesting that this phenomenon (Al3+/Zn2+ interaction) can be preserved in higher plants. Subsequently induced cell death in tobacco cells was analyzed by lethal cell staining with Evans blue. Obtained results indicated that presence of Zn2+ at physiological concentrations can protect the cells by preventing the Al3+-induced superoxide generation and cell death. Furthermore, the regulation of the Ca2+ signaling, i.e., change in the cytosolic Ca2+ ion concentration, and the cross-talks among the elements which participate in the pathway were further explored. PMID:26648960

  17. Extracellular but not cytosolic superoxide dismutase protects against oxidant-mediated endothelial dysfunction

    Directory of Open Access Journals (Sweden)

    Erin L. Foresman

    2013-01-01

    Full Text Available Superoxide (O2•− contributes to the development of cardiovascular disease. Generation of O2•− occurs in both the intracellular and extracellular compartments. We hypothesized that the gene transfer of cytosolic superoxide dismutase (SOD1 or extracellular SOD (SOD3 to blood vessels would differentially protect against O2•−-mediated endothelial-dependent dysfunction. Aortic ring segments from New Zealand rabbits were incubated with adenovirus (Ad containing the gene for Escherichia coli β-galactosidase, SOD1, or SOD3. Activity assays confirmed functional overexpression of both SOD3 and SOD1 isoforms in aorta 24 h following gene transfer. Histochemical staining for β-galactosidase showed gene transfer occurred in the endothelium and adventitia. Next, vessels were prepared for measurement of isometric tension in Kreb's buffer containing xanthine. After precontraction with phenylephrine, xanthine oxidase impaired relaxation to the endothelium-dependent dilator acetylcholine (ACh, max relaxation 33±4% with XO vs. 64±3% without XO, p<0.05, whereas relaxation to the endothelium-independent dilator sodium nitroprusside was unaffected. In the presence of XO, maximal relaxation to ACh was improved in vessels incubated with AdSOD3 (55±2%, p<0.05 vs. control but not AdSOD1 (34±4%. We conclude that adenoviral-mediated gene transfer of SOD3, but not SOD1, protects the aorta from xanthine/XO-mediated endothelial dysfunction. These data provide important insight into the location and enzymatic source of O2•− production in vascular disease.

  18. Mitochondrial p38β and manganese superoxide dismutase interaction mediated by estrogen in cardiomyocytes.

    Directory of Open Access Journals (Sweden)

    Han Liu

    Full Text Available While etiology behind the observed acceleration of ischemic heart disease in postmenopausal women is poorly understood, collective scientific data suggest cardioprotective effects of the endogenous female sex hormone, estrogen. We have previously shown that 17β-estradiol (E2 protects cardiomyocytes exposed to hypoxia-reoxygenation (H/R by inhibiting p38α - p53 signaling in apoptosis and activating pro-survival p38β mitogen activated protein kinase (p38β MAPK, leading to suppression of reactive oxygen species (ROS post H/R. However, little is known about the mechanism behind the antioxidant actions of E2-dependent p38β. The aim of this study is to determine whether the cytoprotection by estrogen involves regulation of manganese superoxide dismutase (MnSOD, a major mitochondrial ROS scavenging enzyme, via cardiac p38β.We identified mitochondrial p38β by immunocytochemistry and by immunoblotting in mitochondria isolated from neonatal cardiomyocytes of Sprague-Dawley rats. E2 facilitated the mitochondrial localization of the active form of the kinase, phosphorylated p38β (p-p38β. E2 also reduced the H/R-induced mitochondrial membrane potential decline, augmented the MnSOD activity and suppressed anion superoxide generation, while the dismutase protein expression remained unaltered. Co-immunoprecipitation studies showed physical association between MnSOD and p38β. p38β phosphorylated MnSOD in an E2-dependent manner in in-vitro kinase assays.This work demonstrates for the first time a mitochondrial pool of active p38β and E2-mediated phosphorylation of MnSOD by the kinase. The results shed light on the mechanism behind the cytoprotective actions of E2 in cardiomyocytes under oxidative stress.

  19. Conservative numerical methods for a two-temperature resistive MHD model with self-generated magnetic field term

    Directory of Open Access Journals (Sweden)

    Imbert-Gérard Lise-Marie

    2011-11-01

    Full Text Available We propose numerical methods on Cartesian meshes for solving the 2-D axisymmetric two-temperature resistivive magnetohydrodynamics equations with self-generated magnetic field and Braginskii’s [1] closures. These rely on a splitting of the complete system in several subsystems according to the nature of the underlying mathematical operator. The hyperbolic part is solved using conservative high-order dimensionally split Lagrange-remap schemes whereas semi-implicit diffusion operators have been developed for the thermal and resistive conduction equations. Source terms are treated explictly. Numerical results on the deceleration phase of an ICF implosion test problem are proposed, a benchmark which was initially proposed in [2]. Nous proposons dans cet article des méthodes numériques pour les équations de la magnétohydrodynamique résistive à deux températures avec champ magnétique auto-généré et relations de fermeture de Braginskii [1] en géométrie 2-D axisymétrique sur maillage cartésien. Celles-ci sont basées sur une décomposition du système complet selon la nature des opérateurs mathématiques sous-jacents. La partie hyperbolique est résolue par des schémas conservatifs Lagrange-projection d’ordre élevé en directions alternées tandis que des opérateurs de diffusion semi-implicites ont été développés pour les équations de conduction thermique et résistive. Les termes sources sont traités de manière explicite. Des résultats numériques sur un cas-test simulant la phase de décélération d’une implosion de capsule FCI sont proposés, ce benchmark ayant été initialement présenté dans [2].

  20. Degradation of Alloy 800 steam generator tubing and its long-term behaviour predictions for plant life management

    International Nuclear Information System (INIS)

    Lu, Y.C.; Tapping, R.L.; Pandey, M.D.

    2009-01-01

    Alloy 800 tubing has a good service record in steam generators (SGs) in both German pressurized water reactors and CANDU 6 reactors, however, a recent comprehensive examination of several ex-service SG tubes removed from Darlington Nuclear Generating Station (DNGS) found that these SG tubes (which had experienced shallow pitting in service) were more susceptible to pitting corrosion in laboratory tests than a reference nuclear grade Alloy 800 tubing under SG crevice chemistry conditions. This was an unexpected finding and has raised questions about possible effects of in-service 'aging' on SG tubing. In addition, there has also been recent evidence that a few Alloy 800 tubes have experienced stress corrosion cracking (SCC) in some German pressurized water reactors (PWRs), possibly after many years of degradation-free service, although the inspection history of these tubes is not available to confirm that the reported degradation initiated recently. These findings suggest that Alloy 800 tubing may have some aging degradation susceptibility after many years of service. To provide support for a proactive SG aging management, a survey on the corrosion susceptibility of the archived Alloy 800 tubing from CANDU SGs under plausible crevice chemistry conditions was conducted to assess the potential material degradation issues in CANDU SGs. Experimental work was also performed to investigate the root cause leading to Alloy 800 SG tubing degradation. The results from this study suggested that a combination of negative factors; aggressive chemistry resulting from impurity ingress into the secondary side of the SGs, elevated electrochemical corrosion potential (ECP) during SG transients and surface strain/plastic deformation, might have led to the degradation of the ex-service SG tubing. The studies have shown that each of these conditions in isolation does not cause degradation of Alloy 800 SG tubing; a synergistic combination of factors is required. The OPEX and experimental

  1. Superoxide activates mitochondrial uncoupling protein 2 from the matrix side. Studies using targeted antioxidants.

    Science.gov (United States)

    Echtay, Karim S; Murphy, Michael P; Smith, Robin A J; Talbot, Darren A; Brand, Martin D

    2002-12-06

    Superoxide activates nucleotide-sensitive mitochondrial proton transport through the uncoupling proteins UCP1, UCP2, and UCP3 (Echtay, K. S., et al. (2002) Nature 415, 1482-1486). Two possible mechanisms were proposed: direct activation of the UCP proton transport mechanism by superoxide or its products and a cycle of hydroperoxyl radical entry coupled to UCP-catalyzed superoxide anion export. Here we provide evidence for the first mechanism and show that superoxide activates UCP2 in rat kidney mitochondria from the matrix side of the mitochondrial inner membrane: (i) Exogenous superoxide inhibited matrix aconitase, showing that external superoxide entered the matrix. (ii) Superoxide-induced uncoupling was abolished by low concentrations of the mitochondrially targeted antioxidants 10-(6'-ubiquinonyl)decyltriphenylphosphonium (mitoQ) or 2-[2-(triphenylphosphonio)ethyl]-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol bromide (mitoVit E), which are ubiquinone (Q) or tocopherol derivatives targeted to the matrix by covalent attachment to triphenylphosphonium cation. However, superoxide-induced uncoupling was not affected by similar concentrations of the nontargeted antioxidants Q(o), Q(1), decylubiquinone, vitamin E, or 6-hydroxy-2,5,7,8-tetramethylchroman 2-carboxylic acid (TROLOX) or of the mitochondrially targeted but redox-inactive analogs decyltriphenylphosphonium or 4-chlorobutyltriphenylphosphonium. Thus matrix superoxide appears to be necessary for activation of UCP2 by exogenous superoxide. (iii) When the reduced to oxidized ratio of mitoQ accumulated by mitochondria was increased by inhibiting cytochrome oxidase, it induced nucleotide-sensitive uncoupling that was not inhibited by external superoxide dismutase. Under these conditions quinols are known to produce superoxide, and because mitoQ is localized within the mitochondrial matrix this suggests that production of superoxide in the matrix was sufficient to activate UCP2. Furthermore, the superoxide

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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...

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

    International Nuclear Information System (INIS)

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

    1988-01-01

    Covalent conjugation of superoxide dismutase and catalase with polyethylene glycol (PEG) increases the circulatory half-lives of these enzymes from 125 I-PEG-catalase or 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

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

    Science.gov (United States)

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

    2017-01-01

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

  6. Biomaterial-induced alterations of neutrophil superoxide production.

    Science.gov (United States)

    Kaplan, S S; Basford, R E; Mora, E; Jeong, M H; Simmons, R L

    1992-08-01

    Because periprosthetic infection remains a vexing problem for patients receiving implanted devices, we evaluated the effect of several materials on neutrophil free radical production. Human peripheral blood neutrophils were incubated with several sterile, lipopolysaccharide (LPS)-free biomaterials used in surgically implantable prosthetic devices: polyurethane, woven dacron, and velcro. Free radical formation as the superoxide (O2-) anion was evaluated by cytochrome c reduction in neutrophils that were exposed to the materials and then removed and in neutrophils allowed to remain in association with the materials. Neutrophils exposed to polyurethane or woven dacron for 30 or 60 min and then removed consistently exhibited an enhanced release of O2- after simulation via receptor engagement with formyl methionyl-leucyl-phenylalanine. Enhanced reactivity to stimulation via protein kinase C with phorbol myristate acetate, however, was not consistently observed. The cells evaluated for O2- release during continuous association with the biomaterials showed enhanced metabolic activity during short periods of association (especially with polyurethane and woven dacron). Although O2- release by neutrophils in association with these materials decreased with longer periods of incubation, it was not obliterated. These studies, therefore, show that several commonly used biomaterials activate neutrophils soon after exposure and that this activated state diminishes with prolonged exposure but nevertheless remains measurable. The diminishing level of activity with prolonged exposure, however, suggests that ultimately a depletion of reactivity may occur and may result in increased susceptibility to periprosthetic infection.

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

    Science.gov (United States)

    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.

  8. Evolution of safety standards for the long-term management of nuclear waste, and their application in Ontario Power Generation

    International Nuclear Information System (INIS)

    Kempe, T.F.

    2006-01-01

    This paper examines the need to develop current radiation protection methodologies further in order to take account of the special features of long-term waste management. The need to expand the scope and nature of regulatory submissions is also addressed. It is concluded that an international consensus is emerging as to requirements for a safety case for long-term waste management, and on safety assessment approaches and criteria to be applied in the regulation of long-term waste management facilities. The application of some of this methodology in preliminary concept assessments carried out by OPG for long-term waste management facilities is described. (author)

  9. Using OpenTarget to Generate Potential Countermeasures for Long-Term Space Exposure from Data Available on GeneLab

    Science.gov (United States)

    Beheshti, Afshin

    2018-01-01

    GeneLab as a general tool for the scientific community; Utilizing GeneLab datasets to generate hypothesis and determining potential biological targets against health risks due to long-term space missions; How can OpenTarget be used to discover novel drugs to test as countermeasures that can be utilized by astronauts.

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

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Silva, Teresa; Trincão, José; Carvalho, Ana L.; Bonifácio, Cecília; Auchère, Françoise; Moura, Isabel; Moura, José J. G.; Romão, Maria J., E-mail: mromao@dq.fct.unl.pt [REQUIMTE Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)

    2005-11-01

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

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

    International Nuclear Information System (INIS)

    Santos-Silva, Teresa; Trincão, José; Carvalho, Ana L.; Bonifácio, Cecília; Auchère, Françoise; Moura, Isabel; Moura, José J. G.; Romão, Maria J.

    2005-01-01

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

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

    Science.gov (United States)

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

    2017-05-01

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

  13. Increased expression of native cytosolic Cu/Zn superoxide dismutase and ascorbate peroxidase improves tolerance to oxidative and chilling stresses in cassava (Manihot esculenta Crantz)

    OpenAIRE

    Xu, Jia; Yang, Jun; Duan, Xiaoguang; Jiang, Yueming; Zhang, Peng

    2014-01-01

    Background Cassava (Manihot esculenta Crantz) is a tropical root crop, and is therefore, extremely sensitive to low temperature; its antioxidative response is pivotal for its survival under stress. Timely turnover of reactive oxygen species (ROS) in plant cells generated by chilling-induced oxidative damages, and scavenging can be achieved by non-enzymatic and enzymatic reactions in order to maintain ROS homeostasis. Results Transgenic cassava plants that co-express cytosolic superoxide dismu...

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

    International Nuclear Information System (INIS)

    Lespade, Laure

    2016-01-01

    Highlights: • Ab initio molecular dynamics is performed to describe the reaction of quercetin and superoxide. • The reaction occurs near the sites 4′ and 7 when the system contains sufficiently water molecules. • The difference of reactivity of superoxide compared to commonly used radicals as DPPH · or ABTS ·+ is explained. - Abstract: 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lespade, Laure, E-mail: l.lespade@ism.u-bordeaux1.fr

    2016-08-22

    Highlights: • Ab initio molecular dynamics is performed to describe the reaction of quercetin and superoxide. • The reaction occurs near the sites 4′ and 7 when the system contains sufficiently water molecules. • The difference of reactivity of superoxide compared to commonly used radicals as DPPH{sup ·} or ABTS{sup ·+} is explained. - Abstract: 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. EPR detection of cellular and mitochondrial superoxide using cyclic hydroxylamines.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Naloxone inhibits superoxide but not enzyme release by human neutrophils

    Energy Technology Data Exchange (ETDEWEB)

    Simpkins, C.; Alailima, S.; Tate, E.

    1986-03-01

    The release of toxic oxygen metabolites and enzymes by phagocytic cells is thought to play a role in the multisystemic tissue injury of sepsis. Naloxone protects septic animals. We have found that at concentrations administered to animals (10/sup -7/ to 10/sup -4/M), naloxone inhibited (p < .001) the release of superoxide (O/sub 2//sup -/) by human neutrophils (HN), stimulated with N-formyl methionyl leucyl phenylalanine (FMLP). Naloxone had no effect on cell viability. Maximum inhibition was 65% of the total O/sub 2//sup -/ released (13.1 nMoles/8 min/320,000 cells). FMLP-stimulated release of beta-glucoronidase or lysozyme was not altered by naloxone. Naloxone had no effect on the binding of /sup 3/H FMLP to HN. Using /sup 3/H naloxone and various concentrations of unlabeled naloxone higher affinity (K/sub D/ = 12nM) and lower affinity (K/sub D/ = 4.7 x 10/sup -5/) binding sites were detected. The K/sub D/ of the low affinity site corresponded to the ED/sub 50/ for naloxone inhibition of O/sub 2//sup -/ (1 x 10/sup -5/M). Binding to this low affinity site was decreased by (+) naloxone, beta-endorphin and N acetyl beta-endorphin, but not by leu-enkephalin, thyrotropin releasing factor, prostaglandin D/sub 2/ or E/sub 2/. Conclusions: (1) naloxone inhibits FMLP-stimulated O/sub 2/ but not enzyme release, (2) this inhibition is not due to alteration of FMLP receptor binding, (3) naloxone may act via a low affinity binding site which is ligand specific, and (4) a higher affinity receptor is present on HN.

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

    Science.gov (United States)

    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.

  20. Similar Transition States Mediate the Q-cycle and Superoxide Production by the Cytochrome bc1 Complex

    International Nuclear Information System (INIS)

    Forquer, Isaac P.; Covian, Raul; Bowman, Michael K.; Trumpower, Bernard; Kramer, David M.

    2006-01-01

    The cytochrome bc complexes found in mitochondria, chloroplasts and many bacteria catalyze a critical reaction in their respective electron transport chains. The quinol oxidase (Qo) site in this complex oxidizes a hydroquinone (quinol), reducing two one-electron carriers, a low-potential cytochrome b heme and a ''Rieske'' iron-sulfur cluster. The overall electron transfer reactions are coupled to transmembrane translocation of protons via a ''Q-cycle'' mechanism, which generates proton motive force for ATP synthesis. Since semiquinone intermediates of quinol oxidation are generally highly reactive, one of the key questions in this field is: how does the Qo site oxidize quinol without the production of deleterious side reactions including superoxide production? We attempt to test three possible general models to account for this behavior: (1) The Qo site semiquinone (or quinol:imidazolate complex) is unstable and thus occurs at a very low steady-state concentration, limiting O2 reduction; (2) the Qo site semiquinone is highly stabilized making it unreactive towards oxygen; and (3) the Qo site catalyzes a quantum mechanically-coupled two-electron/two proton transfer without a semiquinone intermediate. Enthalpies of activation were found to be almost identical between the uninhibited Q-cycle and superoxide production in the presence of Antimycin A in wild type. This behavior was also preserved in a series of mutants with altered driving forces for quinol oxidation. Overall, the data supports models where the rate-limiting step for both Q-cycle and superoxide production are essentially identical, consistent with model 1 but requiring modifications to models 2 and 3

  1. Direct Comparison of the Enzymatic Characteristics and Superoxide Production of the Four Aldehyde Oxidase Enzymes Present in Mouse.

    Science.gov (United States)

    Kücükgöze, Gökhan; Terao, Mineko; Garattini, Enrico; Leimkühler, Silke

    2017-08-01

    Aldehyde oxidases (AOXs) are molybdoflavoenzymes with an important role in the metabolism and detoxification of heterocyclic compounds and aliphatic as well as aromatic aldehydes. The enzymes use oxygen as the terminal electron acceptor and produce reduced oxygen species during turnover. Four different enzymes, mAOX1, mAOX3, mAOX4, and mAOX2, which are the products of distinct genes, are present in the mouse. A direct and simultaneous comparison of the enzymatic properties and characteristics of the four enzymes has never been performed. In this report, the four catalytically active mAOX enzymes were purified after heterologous expression in Escherichia coli The kinetic parameters of the four mouse AOX enzymes were determined and compared with the use of six predicted substrates of physiologic and toxicological interest, i.e., retinaldehyde, N 1 -methylnicotinamide, pyridoxal, vanillin, 4-(dimethylamino)cinnamaldehyde ( p- DMAC), and salicylaldehyde. While retinaldehyde, vanillin, p- DMAC, and salycilaldehyde are efficient substrates for the four mouse AOX enzymes, N 1 -methylnicotinamide is not a substrate of mAOX1 or mAOX4, and pyridoxal is not metabolized by any of the purified enzymes. Overall, mAOX1, mAOX2, mAOX3, and mAOX4 are characterized by significantly different K M and k cat values for the active substrates. The four mouse AOXs are also characterized by quantitative differences in their ability to produce superoxide radicals. With respect to this last point, mAOX2 is the enzyme generating the largest rate of superoxide radicals of around 40% in relation to moles of substrate converted, and mAOX1, the homolog to the human enzyme, produces a rate of approximately 30% of superoxide radicals with the same substrate. Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.

  2. Senescence marker protein-30/superoxide dismutase 1 double knockout mice exhibit increased oxidative stress and hepatic steatosis

    Directory of Open Access Journals (Sweden)

    Yoshitaka Kondo

    2014-01-01

    Full Text Available Superoxide dismutase 1 (SOD1 is an antioxidant enzyme that converts superoxide anion radicals into hydrogen peroxide and molecular oxygen. The senescence marker protein-30 (SMP30 is a gluconolactonase that functions as an antioxidant protein in mammals due to its involvement in ascorbic acid (AA biosynthesis. SMP30 also participates in Ca2+ efflux by activating the calmodulin-dependent Ca2+-pump. To reveal the role of oxidative stress in lipid metabolism defects occurring in non-alcoholic fatty liver disease pathogenesis, we generated SMP30/SOD1-double knockout (SMP30/SOD1-DKO mice and investigated their survival curves, plasma and hepatic lipid profiles, amounts of hepatic oxidative stress, and hepatic protein levels expressed by genes related to lipid metabolism. While SMP30/SOD1-DKO pups had no growth retardation by 14 days of age, they did have low plasma and hepatic AA levels. Thereafter, 39% and 53% of male and female pups died by 15–24 and 89 days of age, respectively. Compared to wild type, SMP30-KO and SOD1-KO mice, by 14 days SMP30/SOD1-DKO mice exhibited: (1 higher plasma levels of triglyceride and aspartate aminotransferase; (2 severe accumulation of hepatic triglyceride and total cholesterol; (3 higher levels of superoxide anion radicals and thiobarbituric acid reactive substances in livers; and (4 decreased mRNA and protein levels of Apolipoprotein B (ApoB in livers – ApoB is an essential component of VLDL secretion. These results suggest that high levels of oxidative stress due to concomitant deficiency of SMP30 and/or AA, and SOD1 cause abnormal plasma lipid metabolism, hepatic lipid accumulation and premature death resulting from impaired VLDL secretion.

  3. The activity of catalase and superoxide dismutase in isogenous bacteria strains with different radioresistance

    International Nuclear Information System (INIS)

    Vasil'eva, E.I.; Goncharenko, E.N.; Yudz, T.I.; Samojlenko, I.I.

    1984-01-01

    The catalase and superoxide dismutase activity in isogenous bacterial strains with various radiosensitivity is investigated. In micrococcus radiodurans mutants with defects in the DNA repair systems the superoxide dismutase activity is lower than in the wild type cells. In investigated Escherichia coli strains differing in radiosensitivity, no alteration in catalase and superoxide dismutase activity is found. The conclusion is drawn that viability of bacteria subjected to the effect of ionizing radiations is determined by the efficiency of DNA repair systems whose functional reliability is sometimes connected with the catalase and suferoxide dismutase activity

  4. Conjugates of Superoxide Dismutase 1 with Amphiphilic Poly(2-oxazoline) Block Copolymers for Enhanced Brain Delivery: Synthesis, Characterization and Evaluation in Vitro and in Vivo

    KAUST Repository

    Tong, Jing; Yi, Xiang; Luxenhofer, Robert; Banks, William A.; Jordan, Rainer; Zimmerman, Matthew C.; Kabanov, Alexander V.

    2013-01-01

    Superoxide dismutase 1 (SOD1) efficiently catalyzes dismutation of superoxide, but its poor delivery to the target sites in the body, such as brain, hinders its use as a therapeutic agent for superoxide-associated disorders. Here to enhance

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

    Science.gov (United States)

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

    2016-03-01

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

  6. Effects of superoxide dismutase, dithiothreitol and formate ion on the inactivation of papain by hydroxyl and superoxide radicals in aerated solutions

    International Nuclear Information System (INIS)

    Lin, W.S.; Armstrong, D.A.

    1978-01-01

    Losses in enzyme activity and sulphydryl content have been studied in aerated papain solutions containing formate, superoxide dismutase and dithiothreitol. Both formate and dithiothreitol converted .OH to .0 2 -, whereas superoxide dismutase completely suppressed the inactivation by .0 2 -. Using results from all systems, the fraction of .0 2 - reactions with papain that caused inactivation of the enzyme was 0.33+-0.07. The results also showed that the fraction of .OH reactions, which cause inactivation of papain, is significantly higher in aerated than in oxygen-free solutions. (author)

  7. Use of Long-Term E. Coli Cultures: To Study Generation of Genetic Diversity & Teach General Microbiology Laboratory Skills

    Science.gov (United States)

    Petrie, Angela; Finkel, Steven E.; Erbe, Jarrod

    2005-01-01

    A novel method of studying the generation of genetic diversity in an undergraduate microbiology laboratory is described. The basis of this approach is the accumulation of mutations that confer a competitive advantage, or growth advantage in stationary phase (GASP) phenotype, to E. coli grown in stationary phase for extended periods of time.

  8. Shopper typologies amongst a Generation Y consumer cohort and variations in terms of age in the fashion apparel market

    Directory of Open Access Journals (Sweden)

    Chengedzai Mafini

    2014-04-01

    Rational: Marketers have ever been concerned with the behaviour of consumers. Generation Y consumers have emerged as an important marketing segment. Consequently, a need exists to investigate behavioural issues pertaining to this age cohort on a continuous basis. Methodology: A survey questionnaire was administered to a convenient sample of 230 Generation Y consumers of fashion apparel. Exploratory factor analysis was used to identify shopper typologies. The Kruskal-Wallis test was used to examine the influence of age on the identified shopper typologies. Findings: The study identified seven shopper typologies that are applicable to the Generation Y cohort. These are quality conscious, brand conscious, novelty seeking, hedonistic, confused by over-choice, habitual, brand loyal and fashion conscious shopper typologies. The study also revealed that younger consumers were found to be more confused by over-choice than their older counterparts. Value of research: These findings may enable marketers to understand and predict the purchase behaviour of Generation Y consumers, thereby facilitating the development and implementation of more effective marketing strategies.

  9. Long-Lived Termite Queens Exhibit High Cu/Zn-Superoxide Dismutase Activity

    Directory of Open Access Journals (Sweden)

    Eisuke Tasaki

    2018-01-01

    Full Text Available In most organisms, superoxide dismutases (SODs are among the most effective antioxidant enzymes that regulate the reactive oxygen species (ROS generated by oxidative energy metabolism. ROS are considered main proximate causes of aging. However, it remains unclear if SOD activities are associated with organismal longevity. The queens of eusocial insects, such as termites, ants, and honeybees, exhibit extraordinary longevity in comparison with the nonreproductive castes, such as workers. Therefore, the queens are promising candidates to study the underlying mechanisms of aging. Here, we found that queens have higher Cu/Zn-SOD activity than nonreproductive individuals of the termite Reticulitermes speratus. We identified three Cu/Zn-SOD sequences and one Mn-SOD sequence by RNA sequencing in R. speratus. Although the queens showed higher Cu/Zn-SOD activity than the nonreproductive individuals, there were no differences in their expression levels of the Cu/Zn-SOD genes RsSOD1 and RsSOD3A. Copper (Cu2+ and Cu+ is an essential cofactor for Cu/Zn-SOD enzyme activity, and the queens had higher concentrations of copper than the workers. These results suggest that the high Cu/Zn-SOD activity of termite queens is related to their high levels of the cofactor rather than gene expression. This study highlights that Cu/Zn-SOD activity contributes to extraordinary longevity in termites.

  10. Comparative study of copper(II)-curcumin complexes as superoxide dismutase mimics and free radical scavengers.

    Science.gov (United States)

    Barik, Atanu; Mishra, Beena; Kunwar, Amit; Kadam, Ramakant M; Shen, Liang; Dutta, Sabari; Padhye, Subhash; Satpati, Ashis K; Zhang, Hong-Yu; Indira Priyadarsini, K

    2007-04-01

    Two stoichiometrically different copper(II) complexes of curcumin (stoichiometry, 1:1 and 1:2 for copper:curcumin), were examined for their superoxide dismutase (SOD) activity, free radical-scavenging ability and antioxidant potential. Both the complexes are soluble in lipids and DMSO. The formation constants of the complexes were determined by voltammetry. EPR spectra of the complexes in DMSO at 77K showed that the 1:2 Cu(II)-curcumin complex is square planar and the 1:1 Cu(II)-curcumin complex is distorted orthorhombic. Cu(II)-curcumin complex (1:1) with larger distortion from square planar structure shows higher SOD activity. These complexes inhibit gamma-radiation induced lipid peroxidation in liposomes and react with DPPH acting as free radical scavengers. One-electron oxidation of the two complexes by radiolytically generated azide radicals in Tx-100 micellar solutions produced phenoxyl radicals, indicating that the phenolic moiety of curcumin in the complexes participates in free radical reactions. Depending on the structure, these two complexes possess different SOD activities, free radical neutralizing abilities and antioxidant potentials. In addition, quantum chemical calculations with density functional theory have been performed to support the experimental observations.

  11. Molecular characterization of two CuZn-superoxide dismutases in a sea anemone.

    Science.gov (United States)

    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.

  12. Effects of Greek legume plant extracts on xanthine oxidase, catalase and superoxide dismutase activities.

    Science.gov (United States)

    Spanou, Chrysoula I; Veskoukis, Aristidis S; Stagos, Dimitrios; Liadaki, Kalliopi; Aligiannis, Nectarios; Angelis, Apostolos; Skaltsounis, Alexios-Leandros; Anastasiadi, Maria; Haroutounian, Serkos A; Kouretas, Dimitrios

    2012-03-01

    Legumes are considered to have beneficial health implications, which have been attributed to their phytochemical content. Polyphenols are considered the most important phytochemical compounds extensively studied for their antioxidant properties. The aim of the present study was to examine the effects of potent antioxidant legume plant extracts on xanthine oxidase (XO), catalase (CAT) and superoxide dismutase (SOD) activities. XO exerts a dual role, as it is the major contributor of free radicals during exercise while it generates uric acid, the most potent antioxidant molecule in plasma. CAT and SOD are two of the main enzymes of the antioxidant defence of tissues. We demonstrate that the majority of the extracts inhibited XO activity, but they had no effect on CAT inhibition and SOD induction when used at low concentrations. These results imply that the tested extracts may be considered as possible source of novel XO inhibitors. However, we have shown that allopurinol administration, a known XO inhibitor, before exercise reduces performance and induces oxidative stress in rats. Considering the fact that the extracts examined had an inhibitory effect on XO activity, possibly posing a restriction in their characterization as antioxidants, phytochemical antioxidant administration before exercise should probably be reconsidered.

  13. Infusing sodium bicarbonate suppresses hydrogen peroxide accumulation and superoxide dismutase activity in hypoxic-reoxygenated newborn piglets.

    Directory of Open Access Journals (Sweden)

    Jiang-Qin Liu

    Full Text Available The effectiveness of sodium bicarbonate (SB has recently been questioned although it is often used to correct metabolic acidosis of neonates. The aim of the present study was to examine its effect on hemodynamic changes and hydrogen peroxide (H(2O(2 generation in the resuscitation of hypoxic newborn animals with severe acidosis.Newborn piglets were block-randomized into a sham-operated control group without hypoxia (n = 6 and two hypoxia-reoxygenation groups (2 h normocapnic alveolar hypoxia followed by 4 h room-air reoxygenation, n = 8/group. At 10 min after reoxygenation, piglets were given either i.v. SB (2 mEq/kg, or saline (hypoxia-reoxygenation controls in a blinded, randomized fashion. Hemodynamic data and blood gas were collected at specific time points and cerebral cortical H(2O(2 production was continuously monitored throughout experimental period. Plasma superoxide dismutase and catalase and brain tissue glutathione, superoxide dismutase, catalase, nitrotyrosine and lactate levels were assayed.Two hours of normocapnic alveolar hypoxia caused cardiogenic shock with metabolic acidosis (PH: 6.99 ± 0.07, HCO(3(-: 8.5 ± 1.6 mmol/L. Upon resuscitation, systemic hemodynamics immediately recovered and then gradually deteriorated with normalization of acid-base imbalance over 4 h of reoxygenation. SB administration significantly enhanced the recovery of both pH and HCO(3- recovery within the first hour of reoxygenation but did not cause any significant effect in the acid-base at 4 h of reoxygenation and the temporal hemodynamic changes. SB administration significantly suppressed the increase in H(2O(2 accumulation in the brain with inhibition of superoxide dismutase, but not catalase, activity during hypoxia-reoxygenation as compared to those of saline-treated controls.Despite enhancing the normalization of acid-base imbalance, SB administration during resuscitation did not provide any beneficial effects on hemodynamic recovery in

  14. Induction of Apoptosis by Superoxide Anion and the Protective Effects of Selenium and Vitamin E

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective The purpose of this study is to investigate the effect of superoxide anion on the apoptosis of cultured fibroblasts and the protective role of selenium and Vitamin E. Methods Cultured fibroblasts (NIH3T3), with or without selenium or vitamin E in the medium, were treated by superoxide anion produced by xanthine/xanthine oxidase reaction system and changes in cell structure and DNA were observed microscopically and electrophoretically. Results Apoptosis was observed when superoxide anion at a concentration of 5 nmol/L or 10 nmol/L had acted on the fibroblasts for 5-10 h. Selenium and Vitamin E in the medium inhibited the apoptosis significantly when their concentrations reached 1.15 mol/L and 2.3 mol/L respectively. Conclusion Selenium and vitamin E have protective effect against the apoptosis induced by superoxide anion. The effect of selenium is more remarkable than that of vitamin E.

  15. Enzymatic Activity Enhancement of Non-Covalent Modified Superoxide Dismutase and Molecular Docking Analysis

    Directory of Open Access Journals (Sweden)

    Fa-Jun Song

    2012-03-01

    Full Text Available The enzyme activity of superoxide dismutase was improved in the pyrogallol autoxidation system by about 27%, after interaction between hydroxypropyl-β-cyclo- dextrin and superoxide dismutase. Fluorescence spectrometry was used to study the interaction between hydroxypropyl-β-cyclodextrin and superoxide dismutase at different temperatures. By doing this, it can be found that these interactions increase fluorescence sensitivity. In the meantime, the synchronous fluorescence intensity revealed the interaction sites to be close to the tryptophan (Trp and tyrosine (Tyr residues of superoxide dismutase. Furthermore, molecular docking was applied to explore the binding mode between the ligands and the receptor. This suggested that HP-β-CD interacted with the B ring, G ring and the O ring and revealed that the lysine (Lys residues enter the nanocavity. It was concluded that the HP-β-CD caused specific conformational changes in SOD by non-covalent modification.

  16. Endogenous superoxide dismutase and catalase activities and radiation resistance in mouse cell lines

    International Nuclear Information System (INIS)

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

    1988-01-01

    The relationship between the endogenous cytoplasmic levels of the enzymes superoxide dismutase and catalase and the inhibition of cell proliferation by γ-radiation has been studied in 11 mouse cell lines. The resistance of these mouse cell lines to radiation was found to vary by over 25-fold. No correlation was found between the cytoplasmic level of CuZn-superoxide dismutase or catalase and the resistance to radiation as measured by extrapolation number (EN), quasi-threshold dose (Dsub(q)), or Dsub(o). None of the cell lines had detectable cytoplasmic Mn-superoxide dismutase. The apparent Ksub(i) of potassium cyanide for mouse CuZn-superoxide dismutase was determined (Ksub(i) = 6.5 μmol dm -3 ). (author)

  17. Trypsin Binding with Copper Ions Scavenges Superoxide: Molecular Dynamics-Based Mechanism Investigation

    Directory of Open Access Journals (Sweden)

    Xin Li

    2018-01-01

    Full Text Available Trypsin is a serine protease, which has been proved to be a novel superoxide scavenger. The burst of superoxide induced by polychlorinated biphenyls can be impeded by trypsin in both wild type and sod knockout mutants of Escherichia coli. The experimental results demonstrated that the activities of superoxide scavenging of trypsin were significantly accelerated by Cu ions. Also, with the addition of Cu ions, a new β-sheet (β7 transited from a random coil in the Cu(II-trypsin (TP system, which was favorable for the formation of more contacts with other sheets of trypsin. Residue–residue network analysis and the porcupine plots proved that the Cu ion in trypsin strengthened some native interactions among residues, which ultimately resulted in much greater stability of the Cu(II-TP system. Moreover, compact and stable trypsin structures with Cu ions might be responsible for significantly provoking the activity of superoxide scavenging.

  18. The Effect of UV-B Radiation on Bufo arenarum Embryos Survival and Superoxide Dismutase Activity

    Science.gov (United States)

    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

  19. [Long-term effect of iodine deficiency on growth and food utilization rate in second filial generation rats].

    Science.gov (United States)

    Muyeseer, Ainiwaer; Zhang, G X; Wang, J; Liu, Y; Meng, X H; Liu, Q

    2017-02-06

    Objective: To study the effect of iodine deficiency on body weight, food consumption, and food utilization rate of second filial generation Wistar rats. Methods: According to the food pattern of a high-iodine deficient population, two types of low-iodine food have been produced using the main crops grown in this area (iodine levels of 50 and 20 μg/kg, respectively). Wistar rats were randomly divided into three groups, normal iodine group (NI group), low-iodine group one (LI group) and low-iodine group two (LII group), using the random number table method and fed diets containing 300, 50, and 20 μg/kg of iodine, respectively. Parental generation rats were fed until they reached reproductive age; first filial generation rats were allocated to the same diet as their mothers. After 3 months of feeding, first filial generation rats gave birth to second filial generation rats; second filial generation rats were allocated to the same diet as their mothers. After feeding for 90, 180, and 270 days, rats were sacrificed. One-way analysis of variance was used to analyze body weight, food intake, and food utilization rate data collected during the time of feeding and blood iodine hormone level, which was determined after sacrifice. Results: The LI and LII groups generally demonstrated decreased activity, slow reaction, and growth retardation compared with the NI group. After 270 days, the urine iodine levels of the LI and LII groups were 1.7 and 0.2 μg/L, respectively, which were significantly lower than the NI group (255.2 μg/L) ( Pfood intake of female and male rats after 270 days were (465.0±27.7), (658.4±28.6) and (423.0±13.2), (548.0±18.8) g, respectively, which were significantly lower than that of the NI group ((499.5±21.8), (760.8±33.0) g) ( Pfood utilization rate of female rats in the LI and LII groups was (8.7±0.4)% and (6.0±0.58)%, which was lower than that of the NI group ((11.7±3.5)%) ( Pfood intake, and food utilization rate among second filial

  20. Extraction of Erythrocyte Enzymes for the Preparation of Polyhemoglobin-catalase-superoxide Dismutase

    OpenAIRE

    Gu, Jingsong; Chang, Thomas Ming Swi

    2009-01-01

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

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

    OpenAIRE

    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 r...

  2. Superoxide dismutase from Trichuris ovis, inhibiton by benzimidazoles and pyrimidine derivatives

    OpenAIRE

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

    1992-01-01

    Three superoxide dismutase isoenzymes of different cellular location were detected in an homogenate of Thrichuris ovis. Each of these molecular forms was purified by differential centrifugation and precipitation with ammonium sulphate, followed by chromatography on DEAE-cellulose and Sephadex G-75 columns. The activity levels of the two molecular forms detected in the mitochondrial (one cyanide sensitive Cu-Zn-SOD and the other cyanide intensitive Mn-Sod were higher than that of the superoxid...

  3. A Column-Generation Approach for a Short-Term Production Planning Problem in Closed-Loop Supply Chains

    Directory of Open Access Journals (Sweden)

    Florian Sahling

    2013-05-01

    Full Text Available We present a new model formulation for a multi-product lot-sizing problem with product returns and remanufacturing subject to a capacity constraint. The given external demand of the products has to be satisfied by remanufactured or newly produced goods. The objective is to determine a feasible production plan, which minimizes production, holding, and setup costs. As the LP relaxation of a model formulation based on the well-known CLSP leads to very poor lower bounds, we propose a column-generation approach to determine tighter bounds. The lower bound obtained by column generation can be easily transferred into a feasible solution by a truncated branch-and-bound approach using CPLEX. The results of an extensive numerical study show the high solution quality of the proposed solution approach.

  4. In-vivo third-harmonic generation microscopy at 1550nm three-dimensional long-term time-lapse studies in living C. elegans embryos

    Science.gov (United States)

    Aviles-Espinosa, Rodrigo; Santos, Susana I. C. O.; Brodschelm, Andreas; Kaenders, Wilhelm G.; Alonso-Ortega, Cesar; Artigas, David; Loza-Alvarez, Pablo

    2011-03-01

    In-vivo microscopic long term time-lapse studies require controlled imaging conditions to preserve sample viability. Therefore it is crucial to meet specific exposure conditions as these may limit the applicability of established techniques. In this work we demonstrate the use of third harmonic generation (THG) microscopy for long term time-lapse three-dimensional studies (4D) in living Caenorhabditis elegans embryos employing a 1550 nm femtosecond fiber laser. We take advantage of the fact that THG only requires the existence of interfaces to generate signal or a change in the refractive index or in the χ3 nonlinear coefficient, therefore no markers are required. In addition, by using this wavelength the emitted THG signal is generated at visible wavelengths (516 nm) enabling the use of standard collection optics and detectors operating near their maximum efficiency. This enables the reduction of the incident light intensity at the sample plane allowing to image the sample for several hours. THG signal is obtained through all embryo development stages, providing different tissue/structure information. By means of control samples, we demonstrate that the expected water absorption at this wavelength does not severely compromise sample viability. Certainly, this technique reduces the complexity of sample preparation (i.e. genetic modification) required by established linear and nonlinear fluorescence based techniques. We demonstrate the non-invasiveness, reduced specimen interference, and strong potential of this particular wavelength to be used to perform long-term 4D recordings.

  5. Dicumarol inhibition of NADPH:quinone oxidoreductase induces growth inhibition of pancreatic cancer via a superoxide-mediated mechanism.

    Science.gov (United States)

    Cullen, Joseph J; Hinkhouse, Marilyn M; Grady, Matthew; Gaut, Andrew W; Liu, Jingru; Zhang, Yu Ping; Weydert, Christine J Darby; Domann, Frederick E; Oberley, Larry W

    2003-09-01

    NADPH:quinone oxidoreductase (NQO(1)), a homodimeric, ubiquitous, flavoprotein, catalyzes the two-electron reduction of quinones to hydroquinones. This reaction prevents the one-electron reduction of quinones by cytochrome P450 reductase and other flavoproteins that would result in oxidative cycling with generation of superoxide (O(2)(.-)). NQO(1) gene regulation may be up-regulated in some tumors to accommodate the needs of rapidly metabolizing cells to regenerate NAD(+). We hypothesized that pancreatic cancer cells would exhibit high levels of this enzyme, and inhibiting it would suppress the malignant phenotype. Reverse transcription-PCR, Western blots, and activity assays demonstrated that NQO(1) was up-regulated in the pancreatic cancer cell lines tested but present in very low amounts in the normal human pancreas. To determine whether inhibition of NQO(1) would alter the malignant phenotype, MIA PaCa-2 pancreatic cancer cells were treated with a selective inhibitor of NQO(1), dicumarol. Dicumarol increased intracellular production of O(2)(.-), as measured by hydroethidine staining, and inhibited cell growth. Both of these effects were blunted with infection of an adenoviral vector containing the cDNA for manganese superoxide dismutase. Dicumarol also inhibited cell growth, plating efficiency, and growth in soft agar. We conclude that inhibition of NQO(1) increases intracellular O(2)(.-) production and inhibits the in vitro malignant phenotype of pancreatic cancer. These mechanisms suggest that altering the intracellular redox environment of pancreatic cancer cells may inhibit growth and delineate a potential strategy directed against pancreatic cancer.

  6. Real-time investigation of antibiotics-induced oxidative stress and superoxide release in bacteria using an electrochemical biosensor.

    Science.gov (United States)

    Liu, Xiaobo; Marrakchi, Mouna; Jahne, Michael; Rogers, Shane; Andreescu, Silvana

    2016-02-01

    The involvement of oxidative stress in the mechanism of antibiotics-meditated cell death is unclear and subject to debate. The kinetic profile and a quantitative relationship between the release of reactive oxygen species (ROS), bacteria and antibiotic type remain elusive. Here we report direct measurements and analytical quantification of the release of superoxide radicals (O2(·-)), a major contributor to ROS, in antibiotics-treated bacterial cultures using a cytochrome c electrochemical biosensor. The specificity of electrochemical measurements was established by the addition of superoxide dismutase (SOD) which decreased the O2(·-) signal. Measurements using a general ROS-specific fluorescence dye and colony forming units (CFU) assays were performed side-by-side to determine the total ROS and establish the relationship between ROS and the degree of lethality. Exposure of Escherichia coli and Listeria monocytogenes cultures to antibiotics increased the release of O2(·-) radicals in a dose-dependent manner, suggesting that the transmembrane generation of ROS may occur as part of the antibiotic action. The study provides a quantitative methodology and fundamental knowledge to further explore the role of oxidative stress in antibiotics-meditated bacterial death and to assess physiological changes associated with the complex metabolic events related to oxidative stress and bacterial resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Investigations of riboflavin photolysis via coloured light in the nitro blue tetrazolium assay for superoxide dismutase activity.

    Science.gov (United States)

    Cheng, Chien-Wei; Chen, Liang-Yü; Chou, Chan-Wei; Liang, Ji-Yuan

    2015-07-01

    Determination of the superoxide dismutase activity is an important issue in the fields of biochemistry and the medical sciences. In the riboflavin/nitro blue tetrazolium (B2/NBT) method, the light sources used for generating superoxide anion radicals from light-excited riboflavin are normally fluorescent lamps. However, the conditions of B2/NBT experiments vary. This study investigated the effect of the light source on the light-excitation of riboflavin. The effectiveness of the photolysis was controlled by the wavelength of the light source. The spectra of fluorescent lamps are composed of multiple colour lights, and the emission spectra of fluorescent lamps made by different manufacturers may vary. Blue light was determined to be the most efficient for the photochemical reaction of riboflavin in visible region. The quality of the blue light in fluorescent lamps is critical to the photo-decomposition of riboflavin. A blue light is better than a fluorescent lamp for the photo-decomposition of riboflavin. The performance of the B2/NBT method is thereby optimized. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Involvement of both protein kinase C and G proteins in superoxide production after IgE triggering in guinea pig eosinophils

    Directory of Open Access Journals (Sweden)

    Toshiya Aizawa

    1997-01-01

    Full Text Available To study the function and mechanism of eosinophils via the low affinity IgE receptor (FceRII, we examined the production of 02 metabolites by measuring the luminol-dependent chemiluminescence (LDCL response and the generation of cysteinyl leukotrienes. Eosinophils obtained from guinea pig peritoneal fluid sensitized with horse serum were purified. Luminol-dependent chemiluminescence was induced by stimulation with monoclonal anti-CD23 antibody, but not by mouse serum (controls. The mean (±SEM value of LDCL was 20.6±1.3X103 c.p.m. This reaction consisted of an initial rapid phase and a propagation phase and ended within lOmin. Guinea pig eosinophils were histochemically stained with monoclonal anti-CD23 antibody. The major product generated in the LDCL response was superoxide, as determined by the measurement of superoxide by cytochrome c reduction and the complete inhibitory effect of superoxide dismutase on the LDCL response. Pretreatment with either pertussis toxin or cholera toxin inhibited the LDCL reaction. Depletion of bivalent ions by EDTA inhibited this response and the protein kinase C inhibitor D-sphingosin inhibited both 1-oleoyl-2-acetyl-glycerol-induced and FcϵRII-mediated LDCL. These findings suggest that the NADPH-protein kinase C pathway may be involved in the FceRII-mediated LDCL response in guinea pig eosinophils.

  9. Effects of marrow storage at 4 degrees C on the subsequent generation of long-term marrow cultures

    International Nuclear Information System (INIS)

    Takahashi, M.; Singer, J.W.

    1985-01-01

    The present study was undertaken to examine the effect of marrow preservation at 4 degrees C on subsequent long-term culture, which evaluates both hematopoietic precursor cells and hematopoietic microenvironmental cells. Storage of unfractionated marrow was superior to storage of buffy-coat cells in tissue culture medium with 20% fetal calf serum. CFU-C recovery in unfractionated marrow was 48.4% at four days and 21.4% at seven days. Long-term marrow cultures from cells stored at 4 degrees C for up to seven days produced CFU-C for up to seven weeks and established confluent marrow stromal cell layers. Suspension cultures of marrow cells preserved at 4 degrees C for seven days cultured with irradiated allogeneic marrow stromal cell layers from normal long-term marrow cultures showed significantly increased CFU-C production from week 2 to week 5 when compared with the control cultures without adherent cell layers. These data suggest that marrow storage at 4 degrees C for up to seven days preserves early hematopoietic precursor cells and microenvironmental cells and may be used for autologous rescue from marrow ablative therapy

  10. Modeling generation expansion in the context of a security of supply mechanism based on long-term auctions. Application to the Colombian case

    International Nuclear Information System (INIS)

    Rodilla, P.; Batlle, C.; Salazar, J.; Sanchez, J.J.

    2011-01-01

    In an attempt to provide electricity generation investors with appropriate economic incentives so as to maintain quality of supply at socially optimal levels, a growing number of electricity market regulators have opted for implementing a security of supply mechanism based on long-term auctions. In this context, the ability to analyze long-term investment dynamics is a key issue not only for market agents, but also for regulators. This paper describes a model developed to serve this purpose. A general system-dynamics-inspired methodology has been designed to be able to simulate these long-term auction mechanisms in the formats presently in place. A full-scale simulation based on the Colombian system was conducted to illustrate model capabilities. (author)

  11. Modeling generation expansion in the context of a security of supply mechanism based on long-term auctions. Application to the Colombian case

    Energy Technology Data Exchange (ETDEWEB)

    Rodilla, P.; Batlle, C. [Institute for Research in Technology, University Pontificia Comillas, Sta. Cruz de Marcenado 26, 28015 Madrid (Spain); Salazar, J. [Empresas Publicas de Medellin, Carrera 58 No. 42-125 Edificio Inteligente, Medellin (Colombia); Sanchez, J.J. [Secretaria de Estado de Cambio Climatico, Ministerio de Medio Ambiente, Rural y Marino. Plaza San Juan de la Cruz, 28071 Madrid (Spain)

    2011-01-15

    In an attempt to provide electricity generation investors with appropriate economic incentives so as to maintain quality of supply at socially optimal levels, a growing number of electricity market regulators have opted for implementing a security of supply mechanism based on long-term auctions. In this context, the ability to analyze long-term investment dynamics is a key issue not only for market agents, but also for regulators. This paper describes a model developed to serve this purpose. A general system-dynamics-inspired methodology has been designed to be able to simulate these long-term auction mechanisms in the formats presently in place. A full-scale simulation based on the Colombian system was conducted to illustrate model capabilities. (author)

  12. Effect of γ-radiation on the activities of superoxide dimutase, catalase and peroxidase on the germinating wheat grain (Triticum aestivum,L.)

    International Nuclear Information System (INIS)

    Chakraborti, M.; Chatterjee, G.C.

    1983-01-01

    Effect of γ-radiation on several enzymes like catalase, peroxidase and superoxide dismutase in different parts of germinating wheat seeds has been studied. It was found that superoxide dismutase activity under the influence of γ-radiation was highest in the embryo part and showed maximum activity, 24 hours after germination. The activity exhibited a gradual decline with time. catalase and peroxidase, the stimulatory efect being maximum in the case of catalase activity. The catalase and peroxidase activities were found to be maximally localised in the embryo part and the highest value was attained after 72 hrs. in the case of catalase and after 48 hrs in the case of peroxidase activity. The results indicate that γ-radiation stimulates free radical generation in the embryo along with subsequent increase in the activities of superoside dismutase, catalase and peroxidase. (author)

  13. Mycobacterium tuberculosis has diminished capacity to counteract redox stress induced by elevated levels of endogenous superoxide.

    Science.gov (United States)

    Tyagi, Priyanka; Dharmaraja, Allimuthu T; Bhaskar, Ashima; Chakrapani, Harinath; Singh, Amit

    2015-07-01

    Mycobacterium tuberculosis (Mtb) has evolved protective and detoxification mechanisms to maintain cytoplasmic redox balance in response to exogenous oxidative stress encountered inside host phagocytes. In contrast, little is known about the dynamic response of this pathogen to endogenous oxidative stress generated within Mtb. Using a noninvasive and specific biosensor of cytoplasmic redox state of Mtb, we for first time discovered a surprisingly high sensitivity of this pathogen to perturbation in redox homeostasis induced by elevated endogenous reactive oxygen species (ROS). We synthesized a series of hydroquinone-based small molecule ROS generators and found that ATD-3169 permeated mycobacteria to reliably enhance endogenous ROS including superoxide radicals. When Mtb strains including multidrug-resistant (MDR) and extensively drug-resistant (XDR) patient isolates were exposed to this compound, a dose-dependent, long-lasting, and irreversible oxidative shift in intramycobacterial redox potential was detected. Dynamic redox potential measurements revealed that Mtb had diminished capacity to restore cytoplasmic redox balance in comparison with Mycobacterium smegmatis (Msm), a fast growing nonpathogenic mycobacterial species. Accordingly, Mtb strains were extremely susceptible to inhibition by ATD-3169 but not Msm, suggesting a functional linkage between dynamic redox changes and survival. Microarray analysis showed major realignment of pathways involved in redox homeostasis, central metabolism, DNA repair, and cell wall lipid biosynthesis in response to ATD-3169, all consistent with enhanced endogenous ROS contributing to lethality induced by this compound. This work provides empirical evidence that the cytoplasmic redox poise of Mtb is uniquely sensitive to manipulation in steady-state endogenous ROS levels, thus revealing the importance of targeting intramycobacterial redox metabolism for controlling TB infection. Copyright © 2015 The Authors. Published by

  14. Superoxide-responsive gene expression in Arabidopsis thaliana and Zea mays.

    Science.gov (United States)

    Xu, Junhuan; Tran, Thu; Padilla Marcia, Carmen S; Braun, David M; Goggin, Fiona L

    2017-08-01

    Superoxide (O 2 - ) and other reactive oxygen species (ROS) are generated in response to numerous biotic and abiotic stresses. Different ROS have been reported to elicit different transcriptional responses in plants, and so ROS-responsive marker genes and promoter::reporter gene fusions have been proposed as indirect means of detecting ROS and discriminating among different species. However, further information about the specificity of transcriptional responses to O 2 - is needed in order to assess potential markers for this critical stress-responsive signaling molecule. Using qRT-PCR, the expression of 12 genes previously reported to be upregulated by O 2 - was measured in Arabidopsis thaliana plants exposed to elicitors of common stress-responsive ROS: methyl viologen (an inducer of O 2 - ), rose bengal (an inducer of singlet oxygen, 1 ΔO 2 ), and exogenous hydrogen peroxide (H 2 O 2 ). Surprisingly, Zinc-Finger Protein 12 (AtZAT12), which had previously been used as a reporter for H 2 O 2 , responded more strongly to O 2 - than to H 2 O 2 ; moreover, the expression of an AtZAT12 promoter-reporter fusion (AtZAT12::Luc) was enhanced by diethyldithiocarbamate, which inhibits dismutation of O 2 - to H 2 O 2 . These results suggest that AtZAT12 is transcriptionally upregulated in response to O 2 - , and that AtZAT12::Luc may be a useful biosensor for detecting O 2 - generation in vivo. In addition, transcripts encoding uncoupling proteins (AtUCPs) showed selectivity for O 2 - in Arabidopsis, and an AtUCP homolog upregulated by methyl viologen was also identified in maize (Zea mays L.), indicating that there are O 2 - -responsive members of this family in monocots. These results expand our limited knowledge of ROS-responsive gene expression in monocots, as well as O 2 - -selective responses in dicots. Copyright © 2017 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

  15. Uncertainty in the labour market: How does fixed-term employment affect fertility and mental health of the young generation?

    OpenAIRE

    Wolfgang Auer; Natalia Danzer

    2015-01-01

    We study the short- to medium-run effects of starting a career on a fixed-term contract on subsequent fertility and health outcomes. We focus on the career start since we expect that temporary contracts and their inherent economic uncertainty imply a path dependence which might have spill-over effects on other domains of life. Our empirical analysis is based on rich data from the German Socio-Economic Panel which provides comprehensive information about individuals’ labour market history as w...

  16. Economically efficient energy generation and energy utilization: Potentials as well as effects in terms of energy, ecology, economy

    International Nuclear Information System (INIS)

    Masuhr, K.P.

    1987-01-01

    As the electric power industry is closely interlaced with the overall power supply system of the country, and especially with the heat market, a study into the impacts of an abandonment of nuclear power is necessary in order to be able to assess the situation in the energy sector at large. The report in hand summarizes the methodology adopted and the frame conditions taken as a basis. The contrast scenario without nuclear energy is explained and interpreted in terms of its effects on the energy market, the economy and the environment. (DG) [de

  17. Mapping of the flux and estimate of the radiation source term of neutron fields generated by the GE PETtrace-8 cyclotron

    International Nuclear Information System (INIS)

    Benavente Castillo, Jhonny Antonio

    2017-01-01

    The use of spectrometric techniques in a cyclotron facility is strongly advised for the complete characterization of the neutron radiation field. In recent years, several studies of neutron spectrometry have been carried out at the Cyclotron of the Development Center of Nuclear Technology (CDTN). The main objective of this work is to propose a methodology for mapping of the flux and estimate of the radiation source term of neutron fields generated by the GE PETtrace-8 cyclotron. The method of neutron activation analysis with gold, indium and nickel activation foils was used to measure the activities induced at specific points in the cyclotron bunker. The irradiations of the activation foils were performed using the intermittent irradiation method to optimize the radiation field during 18 F production. The study of the neutron spectrum was performed using three radiation source terms. The first source term was constructed based on data provided by the cyclotron manufacturer using the neutron cross sections of the ENDF/B-VII library. The other two were proposed considering the irradiation process used in the routine of 18 F production. Both radiation source terms used the LA150H proton cross sections and for the 18 O, the cross sections of the physical model CEM03 (Cascade-exciton model) and TENDL (TALYS-based Evaluated Nuclear Data Library) were used. The results of the source terms in relation to the experimental results, in terms of neutron fluence rates, reaction rates and dose equivalent rates, showed that are in the same order of magnitude as those obtained by Ogata et al, Fujibuchi et al, and Gallerani et al., for the same cyclotron; and by Mendez et al. for a different manufacturing cyclotron. The models of the proposed radiation source terms were validated to obtain the spectra generated during the 18 F production when water enriched at 18 O is bombarded with a proton beam of 16.5 MeV. Finally, the model of the LA150H - TENDL - 2015 radiation source term is

  18. A Representation of the Relative Entropy with Respect to a Diffusion Process in Terms of Its Infinitesimal Generator

    Directory of Open Access Journals (Sweden)

    Oliver Faugeras

    2014-12-01

    Full Text Available In this paper we derive an integral (with respect to time representation of the relative entropy (or Kullback–Leibler Divergence R(μ||P, where μ and P are measures on C([0,T];Rd. The underlying measure P is a weak solution to a martingale problem with continuous coefficients. Our representation is in the form of an integral with respect to its infinitesimal generator. This representation is of use in statistical inference (particularly involving medical imaging. Since R(μ||P governs the exponential rate of convergence of the empirical measure (according to Sanov’s theorem, this representation is also of use in the numerical and analytical investigation of finite-size effects in systems of interacting diffusions.

  19. Is there a water–energy nexus in electricity generation? Long-term scenarios for the western United States

    International Nuclear Information System (INIS)

    Ackerman, Frank; Fisher, Jeremy

    2013-01-01

    Water is required for energy supply, and energy is required for water supply, creating problems as demand for both resources grows. We analyze this “water–energy nexus” as it affects long-run electricity planning in the western United States. We develop four scenarios assuming: no new constraints; limits on carbon emissions; limits on water use; and combined carbon and water limits. We evaluate these scenarios through 2100 under a range of carbon and water prices. The carbon-reducing scenarios become cost-effective at carbon prices of about $50–$70 per ton of CO 2 , moderately high but plausible within the century. In contrast, the water-conserving scenarios are not cost-effective until water prices reach thousands of dollars per acre-foot, well beyond foreseeable levels. This is due in part to the modest available water savings: our most and least water-intensive scenarios differ by less than 1% of the region's water consumption. Under our assumptions, Western electricity generation could be reshaped by the cost of carbon emissions, but not by the cost of water, over the course of this century. Both climate change and water scarcity are of critical importance, but only in the former is electricity generation central to the problem and its solutions. - Highlights: • We model long-run electricity supply and demand for the western United States. • We evaluate the costs of carbon-reducing and water-conserving scenarios. • Carbon-reducing scenarios become cost-effective at carbon prices of $50–70 per ton CO 2 . • Water-conserving scenarios are only cost-effective above $4000/acre-foot of water. • Electricity planning is central to climate policy, but much less so to water planning

  20. Modeling Long-term Creep Performance for Welded Nickel-base Superalloy Structures for Power Generation Systems

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Chen

    2015-01-01

    We report here a constitutive model for predicting long-term creep strain evolution in’ strengthened Ni-base superalloys. Dislocation climb-bypassing’, typical in intermediate’ volume fraction (~20%) alloys, is considered as the primary deformation mechanism. Dislocation shearing’ to anti-phase boundary (APB) faults and diffusional creep are also considered for high-stress and high-temperature low-stress conditions, respectively. Additional damage mechanism is taken into account for rapid increase in tertiary creep strain. The model has been applied to Alloy 282, and calibrated in a temperature range of 1375-1450°F, and stress range of 15-45ksi. The model parameters and a MATLAB code are provided. This report is prepared by Monica Soare and Chen Shen at GE Global Research. Technical discussions with Dr. Vito Cedro are greatly appreciated. This work was supported by DOE program DE-FE0005859

  1. A methodology based on dynamic artificial neural network for short-term forecasting of the power output of a PV generator

    International Nuclear Information System (INIS)

    Almonacid, F.; Pérez-Higueras, P.J.; Fernández, Eduardo F.; Hontoria, L.

    2014-01-01

    Highlights: • The output of the majority of renewables energies depends on the variability of the weather conditions. • The short-term forecast is going to be essential for effectively integrating solar energy sources. • A new method based on artificial neural network to predict the power output of a PV generator one hour ahead is proposed. • This new method is based on dynamic artificial neural network to predict global solar irradiance and the air temperature. • The methodology developed can be used to estimate the power output of a PV generator with a satisfactory margin of error. - Abstract: One of the problems of some renewables energies is that the output of these kinds of systems is non-dispatchable depending on variability of weather conditions that cannot be predicted and controlled. From this point of view, the short-term forecast is going to be essential for effectively integrating solar energy sources, being a very useful tool for the reliability and stability of the grid ensuring that an adequate supply is present. In this paper a new methodology for forecasting the output of a PV generator one hour ahead based on dynamic artificial neural network is presented. The results of this study show that the proposed methodology could be used to forecast the power output of PV systems one hour ahead with an acceptable degree of accuracy

  2. Auction approaches of long-term contracts to ensure generation investment in electricity markets: Lessons from the Brazilian and Chilean experiences

    International Nuclear Information System (INIS)

    Moreno, R.; Barroso, L.A.; Rudnick, H.; Mocarquer, S.; Bezerra, B.

    2010-01-01

    The implementation of auctions of long-term electricity contracts is arising as an alternative to ensure generation investment and therefore achieve a reliable electricity supply. The aim is to reconcile generation adequacy with efficient energy purchase, correct risk allocation among investors and consumers, and the politico-economic environment of the country. In this paper, a generic proposal for a long-term electricity contracts approach is made, including practical design concepts for implementation. This proposal is empirically derived from the auctions implemented in Brazil and Chile during the last 6 years. The study is focused on practices and lessons which are especially useful for regulators and policy makers that want to facilitate the financing of new desirable power plants in risky environments and also efficiently allocate supply contracts among investors at competitive prices. Although this mechanism is generally seen as a significant improvement in market regulation, there are questions and concerns on auction performance that require careful design and which are identified in this paper. In addition, the experiences and proposal described can serve to derive further mechanisms in order to promote the entrance of particular generation technologies, e.g. renewables, in the developed world and therefore achieve a clean electricity supply.

  3. Species-specific control of external superoxide levels by the coral holobiont during a natural bleaching event

    Science.gov (United States)

    Diaz, Julia M.; Hansel, Colleen M.; Apprill, Amy; Brighi, Caterina; Zhang, Tong; Weber, Laura; McNally, Sean; Xun, Liping

    2016-12-01

    The reactive oxygen species superoxide (O2.-) is both beneficial and detrimental to life. Within corals, superoxide may contribute to pathogen resistance but also bleaching, the loss of essential algal symbionts. Yet, the role of superoxide in coral health and physiology is not completely understood owing to a lack of direct in situ observations. By conducting field measurements of superoxide produced by corals during a bleaching event, we show substantial species-specific variation in external superoxide levels, which reflect the balance of production and degradation processes. Extracellular superoxide concentrations are independent of light, algal symbiont abundance and bleaching status, but depend on coral species and bacterial community composition. Furthermore, coral-derived superoxide concentrations ranged from levels below bulk seawater up to ~120 nM, some of the highest superoxide concentrations observed in marine systems. Overall, these results unveil the ability of corals and/or their microbiomes to regulate superoxide in their immediate surroundings, which suggests species-specific roles of superoxide in coral health and physiology.

  4. Oxidation of alpha-tocopherol in micelles and liposomes by the hydroxyl, perhydroxyl, and superoxide free radicals

    International Nuclear Information System (INIS)

    Fukuzawa, K.; Gebicki, J.M.

    1983-01-01

    Rates of oxidation of alpha-tocopherol by the hydroxyl- and superoxide free radicals were measured. The radicals were produced in known yields by radiolysis of aqueous solutions with gamma rays. Two main systems were used to dissolve the tocopherol; micelles, made up from charged and uncharged amphiphiles, and membranes made from dimyristyl phosphatidylcholine which could be charged by addition of stearyl amine or dicetyl phosphate. The HO. radicals were efficient oxidants of alpha-tocopherol in all systems, with up to 83% of radicals generated in micelle and 32% in membrane suspensions initiating the oxidation. The HO 2 radical was an even more effective oxidant, but when most of it was in the O 2 form at neutral or alkaline pH, the oxidation rates became low. Tocopherol held in positively charged micelles or membranes was oxidized at a higher rate by the O 2 than in uncharged or negative particles. Possible biological significance of these results is discussed

  5. Titanium dioxide nanoparticles enhance production of superoxide anion and alter the antioxidant system in human osteoblast cells

    Directory of Open Access Journals (Sweden)

    Niska K

    2015-02-01

    Full Text Available Karolina Niska,1 Katarzyna Pyszka,1 Cecylia Tukaj,2 Michal Wozniak,1 Marek Witold Radomski,3–5 Iwona Inkielewicz-Stepniak1 1Department of Medical Chemistry, 2Department of Electron Microscopy, Medical University of Gdansk, Gdansk, Poland; 3School of Pharmacy and Pharmaceutical Sciences, Trinity Biomedical Sciences Institute, The University of Dublin Trinity College, Dublin, Ireland; 4Kardio-Med Silesia, 5Silesian Medical University, Zabrze, Poland Abstract: Titanium dioxide (TiO2 nanoparticles (NPs are manufactured worldwide for a variety of engineering and bioengineering applications. TiO2NPs are frequently used as a material for orthopedic implants. However, to the best of our knowledge, the biocompatibility of TiO2NPs and their effects on osteoblast cells, which are responsible for the growth and remodeling of the human skeleton, have not been thoroughly investigated. In the research reported here, we studied the effects of exposing hFOB 1.19 human osteoblast cells to TiO2NPs (5–15 nm for 24 and 48 hours. Cell viability, alkaline phosphatase (ALP activity, cellular uptake of NPs, cell morphology, superoxide anion (O2•- generation, superoxide dismutase (SOD activity and protein level, sirtuin 3 (SIR3 protein level, correlation between manganese (Mn SOD and SIR, total antioxidant capacity, and malondialdehyde were measured following exposure of hFOB 1.19 cells to TiO2NPs. Exposure of hFOB 1.19 cells to TiO2NPs resulted in: (1 cellular uptake of NPs; (2 increased cytotoxicity and cell death in a time- and concentration-dependent manner; (3 ultrastructure changes; (4 decreased SOD and ALP activity; (5 decreased protein levels of SOD1, SOD2, and SIR3; (6 decreased total antioxidant capacity; (7 increased O2•- generation; and (8 enhanced lipid peroxidation (malondialdehyde level. The linear relationship between the protein level of MnSOD and SIR3 and between O2•- content and SIR3 protein level was observed. Importantly, the cytotoxic

  6. Not locked-in? The overlooked impact of new gas-fired generation investment on long-term decarbonisation in the UK

    International Nuclear Information System (INIS)

    Chignell, Simon; Gross, Robert J.K.

    2013-01-01

    This paper contrasts the potential increase in gas-fired power generation in the UK in the period to 2020 with the ambitious decarbonisation goals set forth for this sector. An increase in Combined Cycle Gas Turbine (CCGT) capacity, in particular, only represents a threat to long-term decarbonisation if some ‘lock-in’ exists. It is against this background, and in the interest of challenging the perception of no significant lock-in to gas-fired generation, that this paper identifies investment lock-in as phenomenon of relevance to policy-makers. The paper determines both direct and indirect ways in which investment in significant new CCGT capacity could negatively impact on the likelihood of meeting decarbonisation goals through ‘locking-in’ the existing technological system. It also identifies that the technical lifetime, and not just the capital repayment period, of CCGT assets is relevant in understanding the strength of the lock-in. Finally, a regulatory structure that aligns with the long-term targets in place is identified as providing a clear signal for investors and asset owners that may reduce the risk of ‘investment lock-in’. - Highlights: ► The potential conflict between new CCGT and decarbonisation targets is examined. ► A form of ‘hysteretic lock-in’ associated with CCGT investment is identified. ► Potential effects of ‘lock-in’ from new CCGT investment in the UK are highlighted. ► The paper argues for a clear long-term regulatory structure for new CCGT generation.

  7. Capital investment requirements for greenhouse gas emissions mitigation in power generation on near term to century time scales and global to regional spatial scales

    International Nuclear Information System (INIS)

    Chaturvedi, Vaibhav; Clarke, Leon; Edmonds, James; Calvin, Katherine; Kyle, Page

    2014-01-01

    Our paper explores the implication of climate mitigation policy and electricity generation technology performance for capital investment demands by the electric power sector on near term to century time scales. We find that stabilizing GHG emissions will require additional investment in the electricity generation sector over and above investments that would be needed in the absence of climate policy, in the range of 15 to 29 trillion US$ (48–94%) depending on the stringency of climate policy during the period 2015 to 2095 under default technology assumptions. This increase reflects the higher capital intensity of power systems that control emissions as well as increased electrification of the global economy. Limits on the penetration of nuclear and carbon capture and storage technology could increase costs substantially. Energy efficiency improvements can reduce the investment requirement by 18 to 24 trillion US$ (compared to default technology climate policy assumptions), depending on climate policy scenario. We also highlight the implications of different technology evolution scenarios for different regions. Under default technology set, the heaviest investments across scenarios in power generation were observed in China, India, SE Asia and Africa regions with the latter three regions dominating in the second half of the 21st century. - Highlights: • We present electricity generation investment requirement under different scenarios. • A climate policy will lead to substantial increase in investment requirement. • Stringency of climate policy has significant implications for investments. • Technology evolution and performance alter investment requirements significantly. • China, India, Southeast Asia and Africa dominate as investment destinations

  8. Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF α mediators

    International Nuclear Information System (INIS)

    Orona, N.S.; Tasat, D.R.

    2012-01-01

    Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 μM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO 3 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO 3 . We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O 2 − ). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O 2 − may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O 2 − may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium‐related diseases. -- Highlights: ► Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ► At low doses uranyl nitrate induces generation of superoxide anion. ► At high doses uranyl nitrate provokes secretion of TNFα. ► Uranyl nitrate induces apoptosis through all the range of doses tested.

  9. Aliphatic alcohols of illegally produced spirits can act synergistically on superoxide-anion production by human granulocytes.

    Science.gov (United States)

    Arnyas, Ervin M; Pál, László; Kovács, Csilla; Adány, Róza; McKee, Martin; Szűcs, Sándor

    2012-10-01

    Aliphatic alcohols present in illegally produced spirits in a large number of low and middle income countries have been implicated in the etiology of chronic liver disease and cirrhosis. Previous studies have confirmed that chronic alcoholism can lead to increased susceptibility to infectious diseases. Reduced superoxide-anion (O(2)·(-)) production by granulocytes could provide a mechanism by which antimicrobial defense is impaired in alcoholics. In vitro experiments have also demonstrated that ethanol can inhibit granulocyte O(2)·(-) generation. Aliphatic alcohols consumed as contaminants of illicit spirits may also influence O(2)·(-) production thereby contributing to a decrease in microbicidal activity. The aim of this study was to investigate this possibility. It measured the O(2)·(-) production by human granulocytes following treatment of the cells with aliphatic alcohol contaminants found in illicit spirits. Granulocytes were isolated from human buffy coats with centrifugal elutriation and then treated with individual aliphatic alcohols and their mixture. The O(2)·(-) production was stimulated with phorbol-12-13-dibutyrate and N-formyl-methionyl-leucyl-phenylalanine (FMLP) and measured by superoxide dismutase inhibitable reduction of ferricytochrome c. Aliphatic alcohols of illegally produced spirits inhibited the FMLP-induced O(2)·(-) production in a concentration dependent manner. They suppressed O(2)·(-) generation at 2.5-40 times lower concentrations when combined than when tested individually. Aliphatic alcohols found in illegally produced spirits can inhibit FMLP-induced O(2)·(-) production by granulocytes in a concentration-dependent manner. Due to their synergistic effects, it is possible that, in combination with ethanol, they may inhibit O(2)·(-) formation in heavy episodic drinkers.

  10. Long term planning in the hydro-thermal system - A new generation of tools. Final report; Langtidsplanlegging i hydrotermiske system - En ny generasjon verktoey. Sluttrapport

    Energy Technology Data Exchange (ETDEWEB)

    Gjelsvik, Anders; Haugstad, Arne; Honve, Ingrid; Mo, Birger

    2010-01-15

    The project 'Long term planning in the hydro-thermal system - A new generation of tools' has during the project period 2006 - 2009 led to an upgrade of stochastic models for production planning in hydro-thermal power system. The development has primarily been concentrated on ProdRisk, a model for seasonal and long-term planning in hydropower system based on the Stochastic Dual Dynamic Programming (SDDP). The project has lifted the model a long way towards operational use of seasonal planning of hydropower producers. In addition, the quality of the results from the model, makes it considered a good model also for the analysis of development projects in waterways. The report describes this and other activity within the project. Implementation of the project has contributed both to raise the level of tools used for production planning in the Nordic countries and to increase the competence of participants. (AG)

  11. Treating infected diabetic wounds with superoxidized water as anti-septic agent: a preliminary experience

    International Nuclear Information System (INIS)

    Hadi, S.F.; Khaliq, T.; Zubair, M.; Saaiq, M.; Sikandar, I.

    2007-01-01

    To evaluate the effectiveness of superoxidized water (MicrocynTM) in diabetic patients with different wounds. One hundred known diabetic patients were enrolled. Half were randomized to the intervention group (those whose wounds were managed with superoxidized water) and half to the control group (whose wounds were treated with normal saline) using a table of random numbers. The two groups were matched for age, gender, duration of diabetes and category of wound. All patients received appropriate surgical treatment for their wounds as required. Local wound treatment was carried out daily using superoxidized water soaked gauzes on twice daily basis in the intervention group and normal saline in the control group. The treatment was continued until wound healing. The main outcome measures were duration of hospital stay, downgrading of the wound category, wound healing time and need for interventions such as amputation. Statistically significant differences were found in favour of the superoxidized water group with respect to duration of hospital stay, downgrading of the wound category and wound healing time. Although the initial results of employing superoxidized water for the management of infected diabetic wounds are encouraging, further multicentre clinical trials are warranted before this antiseptic is recommended for general use. It may offer an economical alternative to other expensive antiseptics with positive impact on the prevailing infection rates, patient outcomes and patient satisfaction. (author)

  12. Deficiency of superoxide dismutase promotes cerebral vascular hypertrophy and vascular dysfunction in hyperhomocysteinemia.

    Directory of Open Access Journals (Sweden)

    Sanjana Dayal

    Full Text Available There is an emerging consensus that hyperhomocysteinemia is an independent risk factor for cerebral vascular disease and that homocysteine-lowering therapy protects from ischemic stroke. However, the mechanisms by which hyperhomocysteinemia produces abnormalities of cerebral vascular structure and function remain largely undefined. Our objective in this study was to define the mechanistic role of superoxide in hyperhomocysteinemia-induced cerebral vascular dysfunction and hypertrophy. Unlike previous studies, our experimental design included a genetic approach to alter superoxide levels by using superoxide dismutase 1 (SOD1-deficient mice fed a high methionine/low folate diet to produce hyperhomocysteinemia. In wild-type mice, the hyperhomocysteinemic diet caused elevated superoxide levels and impaired responses to endothelium-dependent vasodilators in cerebral arterioles, and SOD1 deficiency compounded the severity of these effects. The cross-sectional area of the pial arteriolar wall was markedly increased in mice with SOD1 deficiency, and the hyperhomocysteinemic diet sensitized SOD1-deficient mice to this hypertrophic effect. Analysis of individual components of the vascular wall demonstrated a significant increase in the content of smooth muscle and elastin. We conclude that superoxide is a key driver of both cerebral vascular hypertrophy and vasomotor dysfunction in this model of dietary hyperhomocysteinemia. These findings provide insight into the mechanisms by which hyperhomocysteinemia promotes cerebral vascular disease and ischemic stroke.

  13. Short-term association between road traffic noise and healthcare demand generated by Parkinson's disease in Madrid, Spain.

    Science.gov (United States)

    Díaz, Julio; Martínez-Martín, Pablo; Rodríguez-Blázquez, Carmen; Vázquez, Blanca; Forjaz, Maria João; Ortiz, Cristina; Carmona, Rocío; Linares, Cristina

    2017-03-23

    To analyse whether there is a short-term association between road traffic noise in the city of Madrid and Parkinson's disease (PD)-related demand for healthcare. Time-series analysis (2008-2009) using variables of analysis linked to emergency and daily PD-related demand for healthcare (ICD-10: G20-G21), namely, PD-hospital admissions (HAs), PD-outpatient visits (OVs) and PD-emergency medical calls in Madrid. The noise pollution measurements used were Leqd, equivalent sound level for the daytime hours (from 8 a.m. to 10 p.m.), and Leqn, equivalent sound level for night time hours (from 10 p.m. to 8 a.m.) in dB(A). We controlled for temperature, pollution, trends and seasons, and used the Poisson regression model to calculate relative risk (RR). The association between Leqd and HAs was found to be linear. Leqd and Leqn at lag 0.1 and temperature at lags 1 and 5 were the only environmental variables associated with increased PD-related healthcare demand. The RR (lag 0) for Leqd and HA was 1.07 (1.04-1.09), the RR (lag 0) for Leqd and OV was 1.28 (1.12-1.45), and the RR (lags 0.1) for Leqn and emergency medical calls was 1.46 (1.06-2.01). The above results indicate that road traffic noise is a risk factor for PD exacerbation. Measures to reduce noise-exposure levels could result in a lower PD-related healthcare demand. Copyright © 2017 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

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

    Science.gov (United States)

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

    2015-12-01

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

  15. Direct antioxidant properties of methotrexate: Inhibition of malondialdehyde-acetaldehyde-protein adduct formation and superoxide scavenging

    Directory of Open Access Journals (Sweden)

    Matthew C. Zimmerman

    2017-10-01

    Full Text Available Methotrexate (MTX is an immunosuppressant commonly used for the treatment of autoimmune diseases. Recent observations have shown that patients treated with MTX also exhibit a reduced risk for the development of cardiovascular disease (CVD. Although MTX reduces systemic inflammation and tissue damage, the mechanisms by which MTX exerts these beneficial effects are not entirely known. We have previously demonstrated that protein adducts formed by the interaction of malondialdehyde (MDA and acetaldehyde (AA, known as MAA-protein adducts, are present in diseased tissues of individuals with rheumatoid arthritis (RA or CVD. In previously reported studies, MAA-adducts were shown to be highly immunogenic, supporting the concept that MAA-adducts not only serve as markers of oxidative stress but may have a direct role in the pathogenesis of inflammatory diseases. Because MAA-adducts are commonly detected in diseased tissues and are proposed to mitigate disease progression in both RA and CVD, we tested the hypothesis that MTX inhibits the generation of MAA-protein adducts by scavenging reactive oxygen species. Using a cell free system, we found that MTX reduces MAA-adduct formation by approximately 6-fold, and scavenges free radicals produced during MAA-adduct formation. Further investigation revealed that MTX directly scavenges superoxide, but not hydrogen peroxide. Additionally, using the Nrf2/ARE luciferase reporter cell line, which responds to intracellular redox changes, we observed that MTX inhibits the activation of Nrf2 in cells treated with MDA and AA. These studies define previously unrecognized mechanisms by which MTX can reduce inflammation and subsequent tissue damage, namely, scavenging free radicals, reducing oxidative stress, and inhibiting MAA-adduct formation.

  16. Structural modeling and in silico analysis of human superoxide dismutase 2.

    Directory of Open Access Journals (Sweden)

    Mariana Dias Castela de Carvalho

    Full Text Available Aging in the world population has increased every year. Superoxide dismutase 2 (Mn-SOD or SOD2 protects against oxidative stress, a main factor influencing cellular longevity. Polymorphisms in SOD2 have been associated with the development of neurodegenerative diseases, such as Alzheimer's and Parkinson's disease, as well as psychiatric disorders, such as schizophrenia, depression and bipolar disorder. In this study, all of the described natural variants (S10I, A16V, E66V, G76R, I82T and R156W of SOD2 were subjected to in silico analysis using eight different algorithms: SNPeffect, PolyPhen-2, PhD-SNP, PMUT, SIFT, SNAP, SNPs&GO and nsSNPAnalyzer. This analysis revealed disparate results for a few of the algorithms. The results showed that, from at least one algorithm, each amino acid substitution appears to harmfully affect the protein. Structural theoretical models were created for variants through comparative modelling performed using the MHOLline server (which includes MODELLER and PROCHECK and ab initio modelling, using the I-Tasser server. The predicted models were evaluated using TM-align, and the results show that the models were constructed with high accuracy. The RMSD values of the modelled mutants indicated likely pathogenicity for all missense mutations. Structural phylogenetic analysis using ConSurf revealed that human SOD2 is highly conserved. As a result, a human-curated database was generated that enables biologists and clinicians to explore SOD2 nsSNPs, including predictions of their effects and visualisation of the alignment of both the wild-type and mutant structures. The database is freely available at http://bioinfogroup.com/database and will be regularly updated.

  17. Formation and scavenging of superoxide in chloroplasts, with relation to injury by sulfur dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Asada, K

    1980-01-01

    Injury of plant leaf cells by sulfur dioxide-exposure is greater in day time than in night. A hypothesis is proposed that the free radical chain oxidation of sulfite is initiated by the superoxide radicals (O/sub 2//sup -/) produced in illuminated chloroplasts, and that the resulting amplified production of O/sub 2//sup -/, the hydroxyl radicals and the bisulfite radicals causes the injury of leaf tissues. In this review, the production of O/sub 2//sup -/ in illuminated chloroplasts and scavenging of O/sub 2//sup -/ by superoxide dismutase and their relation to oxidation of sulfite in chloroplasts are discussed. Superoxide dismutase in chloroplasts plays an important role in protecting leaf cells from injury by sulfur dioxide.

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

    Science.gov (United States)

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

    1992-11-01

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

  19. Extracellular production and degradation of superoxide in the coral Stylophora pistillata and cultured Symbiodinium.

    Directory of Open Access Journals (Sweden)

    Eldad Saragosti

    2010-09-01

    Full Text Available Reactive oxygen species (ROS are thought to play a major role in cell death pathways and bleaching in scleractinian corals. Direct measurements of ROS in corals are conspicuously in short supply, partly due to inherent problems with ROS quantification in cellular systems.In this study we characterized the dynamics of the reactive oxygen species superoxide anion radical (O(2(- in the external milieu of the coral Stylophora pistillata. Using a sensitive, rapid and selective chemiluminescence-based technique, we measured extracellular superoxide production and detoxification activity of symbiont (non-bleached and aposymbiont (bleached corals, and of cultured Symbiodinium (from clades A and C. Bleached and non-bleached Stylophora fragments were found to produce superoxide at comparable rates of 10(-11-10(-9 mol O(2(- mg protein(-1 min(-1 in the dark. In the light, a two-fold enhancement in O(2(- production rates was observed in non-bleached corals, but not in bleached corals. Cultured Symbiodinium produced superoxide in the dark at a rate of . Light was found to markedly enhance O(2(- production. The NADPH Oxidase inhibitor Diphenyleneiodonium chloride (DPI strongly inhibited O(2(- production by corals (and more moderately by algae, possibly suggesting an involvement of NADPH Oxidase in the process. An extracellular O(2(- detoxifying activity was found for bleached and non-bleached Stylophora but not for Symbiodinium. The O(2(- detoxifying activity was partially characterized and found to resemble that of the enzyme superoxide dismutase (SOD.The findings of substantial extracellular O(2(- production as well as extracellular O(2(- detoxifying activity may shed light on the chemical interactions between the symbiont and its host and between the coral and its environment. Superoxide production by Symbiodinium possibly implies that algal bearing corals are more susceptible to an internal build-up of O(2(-, which may in turn be linked to oxidative stress

  20. Endogenous superoxide is a key effector of the oxygen sensitivity of a model obligate anaerobe.

    Science.gov (United States)

    Lu, Zheng; Sethu, Ramakrishnan; Imlay, James A

    2018-04-03

    It has been unclear whether superoxide and/or hydrogen peroxide play important roles in the phenomenon of obligate anaerobiosis. This question was explored using Bacteroides thetaiotaomicron , a major fermentative bacterium in the human gastrointestinal tract. Aeration inactivated two enzyme families-[4Fe-4S] dehydratases and nonredox mononuclear iron enzymes-whose homologs, in contrast, remain active in aerobic Escherichia coli Inactivation-rate measurements of one such enzyme, B. thetaiotaomicron fumarase, showed that it is no more intrinsically sensitive to oxidants than is an E. coli fumarase. Indeed, when the E. coli enzymes were expressed in B. thetaiotaomicron , they no longer could tolerate aeration; conversely, the B. thetaiotaomicron enzymes maintained full activity when expressed in aerobic E. coli Thus, the aerobic inactivation of the B. thetaiotaomicron enzymes is a feature of their intracellular environment rather than of the enzymes themselves. B. thetaiotaomicron possesses superoxide dismutase and peroxidases, and it can repair damaged enzymes. However, measurements confirmed that the rate of reactive oxygen species production inside aerated B. thetaiotaomicron is far higher than in E. coli Analysis of the damaged enzymes recovered from aerated B. thetaiotaomicron suggested that they had been inactivated by superoxide rather than by hydrogen peroxide. Accordingly, overproduction of superoxide dismutase substantially protected the enzymes from aeration. We conclude that when this anaerobe encounters oxygen, its internal superoxide levels rise high enough to inactivate key catabolic and biosynthetic enzymes. Superoxide thus comprises a major element of the oxygen sensitivity of this anaerobe. The extent to which molecular oxygen exerts additional direct effects remains to be determined.

  1. Effect of superoxide anion scavenger on rat hearts with chronic intermittent hypoxia.

    Science.gov (United States)

    Pai, Peiying; Lai, Ching Jung; Lin, Ching-Yuang; Liou, Yi-Fan; Huang, Chih-Yang; Lee, Shin-Da

    2016-04-15

    Only very limited information regarding the protective effects of the superoxide anion scavenger on chronic intermittent hypoxia-induced cardiac apoptosis is available. The purpose of this study is to evaluate the effects of the superoxide anion scavenger on cardiac apoptotic and prosurvival pathways in rats with sleep apnea. Forty-two Sprague-Dawley rats were divided into three groups, rats with normoxic exposure (Control, 21% O2, 1 mo), rats with chronic intermittent hypoxia exposure (Hypoxia, 3-7% O2vs. 21% O2per 40 s cycle, 8 h per day, 1 mo), and rats with pretreatment of the superoxide anion scavenger and chronic intermittent hypoxia exposure (Hypoxia-O2 (-)-Scavenger, MnTMPyP pentachloride, 1 mg/kg ip per day; 3-7% O2vs. 21% O2per 40 s cycle, 8 h per day, 1 mo) at 5-6 mo of age. After 1 mo, the protein levels and apoptotic cells of excised hearts from three groups were measured by Western blotting and terminal deoxynucleotide transferase-mediated dUTP nick end labeling (TUNEL) assay. The superoxide anion scavenger decreased hypoxia-induced myocardial architecture abnormalities, left ventricular hypertrophy, and TUNEL-positive apoptosis. The superoxide anion scavenger decreased hypoxia-induced Fas ligand, Fas death receptors, Fas-associated death domain (FADD), activated caspase-8, and activated caspase-3 (Fas-dependent apoptotic pathway) as well as Bad, activated caspase-9 and activated caspase-3 (mitochondria-dependent apoptotic pathway), endonuclease G (EndoG), apoptosis-inducing factor (AIF), and TUNEL-positive apoptosis. The superoxide anion scavenger increased IGF-1, IGF-1R, p-PI3k, p-Akt, p-Bad, Bcl-2, and Bcl-xL (survival pathway). Our findings imply that the superoxide anion scavenger might prevent cardiac Fas-mediated and mitochondrial-mediated apoptosis and enhance the IGF-1-related survival pathway in chronic intermittent hypoxia. The superoxide anion scavenger may prevent chronic sleep apnea-enhanced cardiac apoptotic pathways and enhances

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

    Science.gov (United States)

    Gu, Jingsong; Chang, Thomas Ming Swi

    2009-01-01

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

  3. Impaired recruitment of seizure-generated neurons into functional memory networks of the adult dentate gyrus following long-term amygdala kindling.

    Science.gov (United States)

    Fournier, Neil M; Botterill, Justin J; Marks, Wendie N; Guskjolen, Axel J; Kalynchuk, Lisa E

    2013-06-01

    Epileptic seizures increase the birth of new neurons in the adult hippocampus. Although the consequences of aberrant neurogenesis on behavior are not fully understood, one hypothesis is that seizure-generated neurons might form faulty circuits that disrupt hippocampal functions, such as learning and memory. In the present study, we employed long-term amygdala kindling (i.e., rats receive 99-electrical stimulations) to examine the effect of repeated seizures on hippocampal neurogenesis and behavior. We labeled seizure-generated cells with the proliferation marker BrdU after 30-stimulations and continued kindling for an additional 4weeks to allow newborn neurons to mature under conditions of repeated seizures. After kindling was complete, rats were tested in a trace fear conditioning task and sacrificed 2h later to examine if 4-week old newborn cells were recruited into circuits involved in the retrieval of emotional memory. Compared to non-kindled controls, long-term kindled rats showed significant impairments in fear memory reflected in a decrease in conditioned freezing to both tone and contextual cues during testing. Moreover, long-term kindling also prevented the activation of 4-week old newborn cells in response to fear memory retrieval. These results indicate that the presence of seizure activity during cell maturation impedes the ability of new neurons to integrate properly into circuits important in memory formation. Together, our findings suggest that aberrant seizure-induced neurogenesis might contribute to the development of learning impairments in chronic epilepsy and raise the possibility that targeting the reduced activation of adult born neurons could represent a beneficial strategy to reverse cognitive deficits in some epileptic patients. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. Enhanced bioelectricity generation of air-cathode buffer-free microbial fuel cells through short-term anolyte pH adjustment.

    Science.gov (United States)

    Ren, Yueping; Chen, Jinli; Li, Xiufen; Yang, Na; Wang, Xinhua

    2018-04-01

    Short-term initial anolyte pH adjustment can relieve the performance deterioration of the single-chamber air-cathode buffer-free microbial fuel cell (BFMFC) caused by anolyte acidification. Adjusting the initial anolyte pH to 9 in 5 running cycles is the optimum strategy. The relative abundance of the electrochemically active Geobacter in the KCl-pH9-MFC anode biofilm increased from 59.01% to 75.13% after the short-term adjustment. The maximum power density (P max ) of the KCl-pH9-MFC was elevated from 316.4mW·m -2 to 511.6mW·m -2 , which was comparable with that of the PBS-MFC. And, after the short-term adjusting, new equilibrium between the anolyte pH and the anode biofilm electrochemical activity has been established in the BFMFC, which ensured the sustainability of the improved bioelectricity generation performance. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Analysis of accident sequences and source terms at treatment and storage facilities for waste generated by US Department of Energy waste management operations

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, C.; Nabelssi, B.; Roglans-Ribas, J.; Folga, S.; Policastro, A.; Freeman, W.; Jackson, R.; Mishima, J.; Turner, S.

    1996-12-01

    This report documents the methodology, computational framework, and results of facility accident analyses performed for the US Department of Energy (DOE) Waste Management Programmatic Environmental Impact Statement (WM PEIS). The accident sequences potentially important to human health risk are specified, their frequencies assessed, and the resultant radiological and chemical source terms evaluated. A personal-computer-based computational framework and database have been developed that provide these results as input to the WM PEIS for the calculation of human health risk impacts. The WM PEIS addresses management of five waste streams in the DOE complex: low-level waste (LLW), hazardous waste (HW), high-level waste (HLW), low-level mixed waste (LLMW), and transuranic waste (TRUW). Currently projected waste generation rates, storage inventories, and treatment process throughputs have been calculated for each of the waste streams. This report summarizes the accident analyses and aggregates the key results for each of the waste streams. Source terms are estimated, and results are presented for each of the major DOE sites and facilities by WM PEIS alternative for each waste stream. Key assumptions in the development of the source terms are identified. The appendices identify the potential atmospheric release of each toxic chemical or radionuclide for each accident scenario studied. They also discuss specific accident analysis data and guidance used or consulted in this report.

  6. Seasonal superoxide overproduction and endothelial activation in guinea-pig heart; seasonal oxidative stress in rats and humans.

    Science.gov (United States)

    Konior, Anna; Klemenska, Emilia; Brudek, Magdalena; Podolecka, Ewa; Czarnowska, Elżbieta; Beręsewicz, Andrzej

    2011-04-01

    Seasonality in endothelial dysfunction and oxidative stress was noted in humans and rats, suggesting it is a common phenomenon of a potential clinical relevance. We aimed at studying (i) seasonal variations in cardiac superoxide (O(2)(-)) production in rodents and in 8-isoprostane urinary excretion in humans, (ii) the mechanism of cardiac O(2)(-) overproduction occurring in late spring/summer months in rodents, (iii) whether this seasonal O(2)(-)-overproduction is associated with a pro-inflammatory endothelial activation, and (iv) how the summer-associated changes compare to those caused by diabetes, a classical cardiovascular risk factor. Langendorff-perfused guinea-pig and rat hearts generated ~100% more O(2)(-), and human subjects excreted 65% more 8-isoprostane in the summer vs. other seasons. Inhibitors of NADPH oxidase, xanthine oxidase, and NO synthase inhibited the seasonal O(2)(-)-overproduction. In the summer vs. other seasons, cardiac NADPH oxidase and xanthine oxidase activity, and protein expression were increased, the endothelial NO synthase and superoxide dismutases were downregulated, and, in guinea-pig hearts, adhesion molecules upregulation and the endothelial glycocalyx destruction associated these changes. In guinea-pig hearts, the summer and a streptozotocin-induced diabetes mediated similar changes, yet, more severe endothelial activation associated the diabetes. These findings suggest that the seasonal oxidative stress is a common phenomenon, associated, at least in guinea-pigs, with the endothelial activation. Nonetheless, its biological meaning (regulatory vs. deleterious) remains unclear. Upregulated NADPH oxidase and xanthine oxidase and uncoupled NO synthase are the sources of the seasonal O(2)(-)-overproduction. Copyright © 2010 Elsevier Ltd. All rights reserved.

  7. Host lysozyme-mediated lysis of Lactococcus lactis facilitates delivery of colitis-attenuating superoxide dismutase to inflamed colons

    Science.gov (United States)

    Ballal, Sonia A.; Veiga, Patrick; Fenn, Kathrin; Michaud, Monia; Kim, Jason H.; Gallini, Carey Ann; Glickman, Jonathan N.; Quéré, Gaëlle; Garault, Peggy; Béal, Chloé; Derrien, Muriel; Courtin, Pascal; Kulakauskas, Saulius; Chapot-Chartier, Marie-Pierre; van Hylckama Vlieg, Johan; Garrett, Wendy S.

    2015-01-01

    Beneficial microbes that target molecules and pathways, such as oxidative stress, which can negatively affect both host and microbiota, may hold promise as an inflammatory bowel disease therapy. Prior work showed that a five-strain fermented milk product (FMP) improved colitis in T-bet−/− Rag2−/− mice. By varying the number of strains used in the FMP, we found that Lactococcus lactis I-1631 was sufficient to ameliorate colitis. Using comparative genomic analyses, we identified genes unique to L. lactis I-1631 involved in oxygen respiration. Respiration of oxygen results in reactive oxygen species (ROS) generation. Also, ROS are produced at high levels during intestinal inflammation and cause tissue damage. L. lactis I-1631 possesses genes encoding enzymes that detoxify ROS, such as superoxide dismutase (SodA). Thus, we hypothesized that lactococcal SodA played a role in attenuating colitis. Inactivation of the sodA gene abolished L. lactis I-1631’s beneficial effect in the T-bet−/− Rag2−/− model. Similar effects were obtained in two additional colonic inflammation models, Il10−/− mice and dextran sulfate sodium-treated mice. Efforts to understand how a lipophobic superoxide anion (O2−) can be detoxified by cytoplasmic lactoccocal SodA led to the finding that host antimicrobial-mediated lysis is a prerequisite for SodA release and SodA’s extracytoplasmic O2− scavenging. L. lactis I-1631 may represent a promising vehicle to deliver antioxidant, colitis-attenuating SodA to the inflamed intestinal mucosa, and host antimicrobials may play a critical role in mediating SodA’s bioaccessibility. PMID:26056274

  8. Projection of primary energy in electricity generation with evaluation of demand and supply of energy in the medium-term horizon (2020), long-term (2035) and very long term (2060); Projecao das energias primarias na geracao de eletricidade com avaliacao da demanda e oferta de energia, em horizonte de medio prazo (2020), longo prazo (2035) e muito longo prazo (2060)

    Energy Technology Data Exchange (ETDEWEB)

    Mafra, Olga Y.; Alvim, Carlos Feu; Eidelman, Frida [Brasil e Economia (Brazil); Guimaraes, Leonam dos Santos [Eletrobras Eletronuclear, Rio de Janeiro, RJ (Brazil)

    2013-01-15

    The Global Energy demand and the participation of electricity in scenarios of medium (2020), long (2035) and very long (2060) terms are estimated. It is also evaluated the share of different primary energies in electricity generation and their availability in the country. Three economic scenarios were considered and different hypothesis regarding the participation of nuclear energy were analyzed. (author)

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

  11. The concentration of extracellular superoxide dismutase in plasma is maintained by LRP-mediated endocytosis

    DEFF Research Database (Denmark)

    Petersen, Steen V; Thøgersen, Ida B; Valnickova, Zuzana

    2010-01-01

    In this study, we show that human extracellular superoxide dismutase (EC-SOD) binds to low-density lipoprotein receptor-related protein (LRP). This interaction is most likely responsible for the removal of EC-SOD from the blood circulation via LRP expressed in liver tissue. The receptor recognition...

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

    Science.gov (United States)

    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...

  13. Superoxide dismutases: Dual roles in controlling ROS damage and regulating ROS signaling.

    Science.gov (United States)

    Wang, Ying; Branicky, Robyn; Noë, Alycia; Hekimi, Siegfried

    2018-04-18

    Superoxide dismutases (SODs) are universal enzymes of organisms that live in the presence of oxygen. They catalyze the conversion of superoxide into oxygen and hydrogen peroxide. Superoxide anions are the intended product of dedicated signaling enzymes as well as the byproduct of several metabolic processes including mitochondrial respiration. Through their activity, SOD enzymes control the levels of a variety of reactive oxygen species (ROS) and reactive nitrogen species, thus both limiting the potential toxicity of these molecules and controlling broad aspects of cellular life that are regulated by their signaling functions. All aerobic organisms have multiple SOD proteins targeted to different cellular and subcellular locations, reflecting the slow diffusion and multiple sources of their substrate superoxide. This compartmentalization also points to the need for fine local control of ROS signaling and to the possibility for ROS to signal between compartments. In this review, we discuss studies in model organisms and humans, which reveal the dual roles of SOD enzymes in controlling damage and regulating signaling. © 2018 Wang et al.

  14. Hydrogen peroxide induce modifications of human extracellular superoxide dismutase that results in enzyme inhibition

    Directory of Open Access Journals (Sweden)

    Randi H. Gottfredsen

    2013-01-01

    Full Text Available Superoxide dismutase (EC-SOD controls the level of superoxide in the extracellular space by catalyzing the dismutation of superoxide into hydrogen peroxide and molecular oxygen. In addition, the enzyme reacts with hydrogen peroxide in a peroxidase reaction which is known to disrupt enzymatic activity. Here, we show that the peroxidase reaction supports a site-specific bond cleavage. Analyses by peptide mapping and mass spectrometry shows that oxidation of Pro112 supports the cleavage of the Pro112–His113 peptide bond. Substitution of Ala for Pro112 did not inhibit fragmentation, indicating that the oxidative fragmentation at this position is dictated by spatial organization and not by side-chain specificity. The major part of EC-SOD inhibited by the peroxidase reaction was not fragmented but found to encompass oxidations of histidine residues involved in the coordination of copper (His98 and His163. These oxidations are likely to support the dissociation of copper from the active site and thus loss of enzymatic activity. Homologous modifications have also been described for the intracellular isozyme, Cu/Zn-SOD, reflecting the almost identical structures of the active site within these enzymes. We speculate that the inactivation of EC-SOD by peroxidase activity plays a role in regulating SOD activity in vivo, as even low levels of superoxide will allow for the peroxidase reaction to occur.

  15. Inclusions of amyotrophic lateral sclerosis-linked superoxide dismutase in ventral horns, liver, and kidney

    DEFF Research Database (Denmark)

    Jonsson, P.A.; Bergemalm, D.; Andersen, P.M.

    2008-01-01

    Mutant superoxide dismutases type 1 (SOD1s) cause amyotrophic lateral sclerosis by an unidentified toxic property. In a patient carrying the G127X truncation mutation, minute amounts of SOD1 were found in ventral horns using a mutant-specific antibody. Still, both absolute levels and ratios versus...

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

    Science.gov (United States)

    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....

  17. Human Manganese Superoxide Dismutase Tyrosine 34 Contribution to Structure and Catalysis

    Science.gov (United States)

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

    2009-01-01

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

  18. Low activity of superoxide dismutase and high activity of glutathione reductase in erythrocytes from centenarians

    DEFF Research Database (Denmark)

    Andersen, Helle Raun; Jeune, B; Nybo, H

    1998-01-01

    aged between 60 and 79 years. MEASUREMENTS: enzyme activities of superoxide dismutase (CuZn-SOD), glutathione peroxidase, catalase and glutathione reductase (GR) in erythrocytes. Functional capacity among the centenarians was evaluated by Katz' index of activities of daily living, the Physical...

  19. The essential dynamics of Cu, Zn superoxide dismutase : Suggestion of intersubunit communication

    NARCIS (Netherlands)

    Chillemi, G; Falconi, M; Amadei, A; Zimatore, G; Desideri, A; DiNola, A

    A 300-ps molecular dynamics simulation of the whole Cu, Zn superoxide dismutase dimer has been carried out in water, and the trajectory has been analyzed by the essential dynamics method. The results indicate that the motion is defined by few preferred directions identified by the first four to six

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

    Science.gov (United States)

    Xiao, Neng; Gourdin, Gerald; Wu, Yiying

    2018-05-22

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

  1. Electricity generation and microbial community in response to short-term changes in stack connection of self-stacked submersible microbial fuel cell powered by glycerol

    DEFF Research Database (Denmark)

    Zhao, Nannan; Angelidaki, Irini; Zhang, Yifeng

    2017-01-01

    community. In this study, a self-stacked submersible microbial fuel cell (SSMFC) powered by glycerol was tested to elucidate this important issue. In series connection, the maximum voltage output reached to 1.15 V, while maximum current density was 5.73 mA in parallel. In both connections, the maximum power......Stack connection (i.e., in series or parallel) of microbial fuel cell (MFC) is an efficient way to boost the power output for practical application. However, there is little information available on short-term changes in stack connection and its effect on the electricity generation and microbial...... density increased with the initial glycerol concentration. However, the glycerol degradation was even faster in parallel connection. When the SSMFC was shifted from series to parallel connection, the reactor reached to a stable power output without any lag phase. Meanwhile, the anodic microbial community...

  2. α and long-lived βγ waste source term. A first generation model for a deep cemented waste repository

    International Nuclear Information System (INIS)

    Lovera, P.; Mangin, J.P.; Jorda, M.; Lewi, J.

    1987-01-01

    According to the normal scenario of radioactivity release to the biosphere, only long-lived nuclides are able to migrate significantly to the surface. A first generation model, concerning a cemented waste of hulls and ends deeply disposed of in a granitic medium is in progress at CEA. Two nuclides have been selected: 237-Neptunium (as a reference of α emitters) and 135-Cesium (as a reference of long-lived β emitters). Attributing the long term activity to these both nuclides leads to a model which is conservative beyond ca. 150000 years. Principal difficulties arise from physico-chemical behaviour of Neptunium in aqueous phase, and from non-linear Cesium adsorption on various media. Condiment code (versions 2 and 3), which is developed parallely to the present model is conceived to take account for these phenomena

  3. Beyond the five-year horizon: long-term outcome of high-risk and inoperable patients undergoing TAVR with first-generation devices.

    Science.gov (United States)

    Deutsch, Marcus-André; Erlebach, Magdalena; Burri, Melchior; Hapfelmeier, Alexander; Witt, Olivia Ganga; Ziegelmueller, Johannes Amadeus; Wottke, Michael; Ruge, Hendrik; Krane, Markus; Piazza, Nicolo; Bleiziffer, Sabine; Lange, Rüdiger

    2018-05-20

    We sought to determine the long-term outcome of high-risk patients who underwent transcatheter aortic valve replacement (TAVR) with first-generation devices with a focus on the identification of predictors for mortality and valve durability. Consecutive patients in our prospective single-centre registry undergoing TAVR with first-generation devices (n=214 CoreValve; n=86 SAPIEN) between 06/2007 and 07/2009 were retrospectively analysed (n=300, mean age 81.43±6.55 years, mean STS score 6.5±4.5%). Kaplan-Meier estimates of survival and the Cox proportional hazards model were used to identify independent predictors of all-cause-mortality. At 1, 5, and 7 years, estimated survival rates were 76.0%, 40.2%, and 23.2%, respectively. Age-adjusted baseline predictors of mortality included atrial fibrillation, impaired kidney function, peripheral artery disease, and mitral regurgitation (≥moderate). Baseline risk-adjusted procedure-related predictors for all-cause mortality included acute kidney injury, neurological events, major vascular complications, and major/life-threatening bleeding. At both five and six years, 78.2% of surviving patients were in NYHA Class I or II. PVL was ≤mild in the majority of patients at discharge and throughout follow-up. At seven years, the overall crude cumulative incidence of structural valve deterioration according to the 2017 EAPCI/ESC/EACTS definition was 14.9% (CoreValve 11.8% vs. SAPIEN 22.6%; p=0.01). Seven years after TAVR, 23.2% of high-risk patients were still alive. Independent predictors of all-cause mortality included both patient- and procedure-related factors. With a cumulative incidence of 14.9% at seven years, there is some suggestion that SVD post TAVR may become increasingly relevant during longer-term follow-up.

  4. Functional and crystallographic characterization of Salmonella typhimurium Cu,Zn superoxide dismutase coded by the sodCI virulence gene

    NARCIS (Netherlands)

    Pesce, A; Battistoni, A; Stroppolo, ME; Polizio, F; Nardini, M; Kroll, JS; Langford, PR; O'Neill, P; Sette, M; Desideri, A; Bolognesi, M

    2000-01-01

    The functional and three-dimensional structural features of Cu,Zn superoxide dismutase coded by the Salmonella typhimurium sodCI gene, have been characterized. Measurements of the catalytic rate indicate that this enzyme is the most efficient superoxide dismutase analyzed so far, a feature that may

  5. Effect of different bulking agents on water variation and thermal balance and their respective contribution to bio-generated heat during long-term storage sludge biodrying process.

    Science.gov (United States)

    Liu, Tiantian; Cui, Chongwei; He, Junguo; Tang, Jian

    2018-04-17

    Biodrying was first used for the post-treatment of long-term storage sludge with vinasse as bulking agents. The effect of different bulking agents on water and heat variation and their respective contributions to bio-generated heat during storage sludge biodrying were investigated. Three different bulking agents (beer lees and distillers grains, with conventional straw used for comparison) were mixed with storage sludge for biodrying for an 18-day period. The results revealed the treatment with beer lees as bulking agent achieved the best performance with the highest water removal capacity (658 g kg -1 initial water). The extent of organic degradation in the mixture was related to the degradation ability of the bulking agents. The degradation of C- and H-containing materials (e.g., carboxylic acid) accounted for volatile solids (VS) loss. Water and thermal analyses showed that evaporation was the main way of water loss (accounting for 90%), while evaporation heat was the main component of heat consumption (accounting for 56.67-60.62%).The biodegradation of bulking agents contributed a high proportion of the bio-generated heat consumed by water evaporation (82.35-86.67%).

  6. A Short-Term Outage Model of Wind Turbines with Doubly Fed Induction Generators Based on Supervisory Control and Data Acquisition Data

    Directory of Open Access Journals (Sweden)

    Peng Sun

    2016-10-01

    Full Text Available This paper presents a short-term wind turbine (WT outage model based on the data collected from a wind farm supervisory control and data acquisition (SCADA system. Neural networks (NNs are used to establish prediction models of the WT condition parameters that are dependent on environmental conditions such as ambient temperature and wind speed. The prediction error distributions are discussed and used to calculate probabilities of the operation of protection relays (POPRs that were caused by the threshold exceedance of the environmentally sensitive parameters. The POPRs for other condition parameters are based on the setting time of the operation of protection relays. The union probability method is used to integrate the probabilities of operation of each protection relay to predict the WT short term outage probability. The proposed method has been used for real 1.5 MW WTs with doubly fed induction generators (DFIGs. The results show that the proposed method is more effective in WT outage probability prediction than traditional methods.

  7. Angiotensin II receptor one (AT1) mediates dextrose induced endoplasmic reticulum stress and superoxide production in human coronary artery endothelial cells.

    Science.gov (United States)

    Haas, Michael J; Onstead-Haas, Luisa; Lee, Tracey; Torfah, Maisoon; Mooradian, Arshag D

    2016-10-01

    Renin-angiotensin-aldosterone system (RAAS) has been implicated in diabetes-related vascular complications partly through oxidative stress. To determine the role of angiotensin II receptor subtype one (AT1) in dextrose induced endoplasmic reticulum (ER) stress, another cellular stress implicated in vascular disease. Human coronary artery endothelial cells with or without AT1 receptor knock down were treated with 27.5mM dextrose for 24h in the presence of various pharmacologic blockers of RAAS and ER stress and superoxide (SO) production were measured. Transfection of cells with AT1 antisense RNA knocked down cellular AT1 by approximately 80%. The ER stress was measured using the placental alkaline phosphatase (ES-TRAP) assay and western blot analysis of glucose regulated protein 78 (GRP78), c-jun-N-terminal kinase 1 (JNK1), phospho-JNK1, eukaryotic translation initiation factor 2α (eIF2α) and phospho-eIF2α measurements. Superoxide (SO) generation was measured using the superoxide-reactive probe 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo[1,2-A]pyrazin-3-one hydrochloride (MCLA) chemiluminescence. In cells with AT1 knock down, dextrose induced ER stress was significantly blunted and treatment with 27.5mM dextrose resulted in significantly smaller increase in SO production compared to 27.5mM dextrose treated and sham transfected cells. Dextrose induced ER stress was reduced with pharmacologic blockers of AT1 (losartan and candesartan) and mineralocorticoid receptor blocker (spironolactone) but not with angiotensin converting enzyme inhibitors (captopril and lisinopril). The dextrose induced SO generation was inhibited by all pharmacologic blockers of RAAS tested. The results indicate that dextrose induced ER stress and SO production in endothelial cells are mediated at least partly through AT1 receptor activation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Arsenic alters monocyte superoxide anion and nitric oxide production in environmentally exposed children

    International Nuclear Information System (INIS)

    Luna, Ana L.; Acosta-Saavedra, Leonor C.; Lopez-Carrillo, Lizbeth; Conde, Patricia; Vera, Eunice; De Vizcaya-Ruiz, Andrea; Bastida, Mariana; Cebrian, Mariano E.; Calderon-Aranda, Emma S.

    2010-01-01

    Arsenic (As) exposure has been associated with alterations in the immune system, studies in experimental models and adults have shown that these effects involve macrophage function; however, limited information is available on what type of effects could be induced in children. The aim of this study was to evaluate effects of As exposure, through the association of inorganic As (iAs) and its metabolites [monomethylated arsenic (MMA) and dimethylated arsenic (DMA)] with basal levels of nitric oxide (NO ·- ) and superoxide anion (O 2 ·- ), in peripheral blood mononuclear cells (PBMC) and monocytes, and NO ·- and O 2 ·- produced by activated monocytes. Hence, a cross-sectional study was conducted in 87 children (6-10 years old) who had been environmentally exposed to As through drinking water. Levels of urinary As species (iAs, MMA and DMA) were determined by hydride generation atomic absorption spectrometry, total As (tAs) represents the sum of iAs and its species; tAs urine levels ranged from 12.3 to 1411 μg/g creatinine. Using multiple linear regression models, iAs presented a positive and statistical association with basal NO ·- in PBMC (β = 0.0048, p = 0.049) and monocytes (β = 0.0044, p = 0.044), while basal O 2 ·- had a significant positive association with DMA (β = 0.0025, p = 0.046). In activated monocytes, O 2 ·- showed a statistical and positive association with iAs (β = 0.0108, p = 0.023), MMA (β = 0.0066, p = 0.022), DMA (β = 0.0018, p = 0.015), and tAs (β = 0.0013, p = 0.015). We conclude that As exposure in the studied children was positively associated with basal levels of NO ·- and O 2 ·- in PBMC and monocytes, suggesting that As induces oxidative stress in circulating blood cells. Additionally, this study showed a positive association of O 2 ·- production with iAs and its metabolites in stimulated monocytes, supporting previous data that suggests that these cells, and particularly the O 2 ·- activation pathway, are relevant targets

  9. Delphinidin prevents high glucose-induced cell proliferation and collagen synthesis by inhibition of NOX-1 and mitochondrial superoxide in mesangial cells

    Directory of Open Access Journals (Sweden)

    Seung Eun Song

    2016-04-01

    Full Text Available This study examined the effect of delphinidin on high glucose-induced cell proliferation and collagen synthesis in mesangial cells. Glucose dose-dependently (5.6–25 mM increased cell proliferation and collagen I and IV mRNA levels, whereas pretreatment with delphinidin (50 μM prevented cell proliferation and the increased collagen mRNA levels induced by high glucose (25 mM. High glucose increased reactive oxygen species (ROS generation, and this was suppressed by pretreating delphinidin or the antioxidant N-acetyl cysteine. NADPH oxidase (NOX 1 was upregulated by high glucose, but pretreatment with delphinidin abrogated this upregulation. Increased mitochondrial superoxide by 25 mM glucose was also suppressed by delphinidin. The NOX inhibitor apocynin and mitochondria-targeted antioxidant Mito TEMPO inhibited ROS generation and cell proliferation induced by high glucose. Phosphorylation of extracellular signal regulated kinase (ERK1/2 was increased by high glucose, which was suppressed by delphinidin, apocynin or Mito TEMPO. Furthermore, PD98059 (an ERK1/2 inhibitor prevented the high glucose-induced cell proliferation and increased collagen mRNA levels. Transforming growth factor (TGF-β protein levels were elevated by high glucose, and pretreatment with delphinidin or PD98059 prevented this augmentation. These results suggest that delphinidin prevents high glucose-induced cell proliferation and collagen synthesis by inhibition of NOX-1 and mitochondrial superoxide in mesangial cells.

  10. Oxidative stress and enzymatic scavenging of superoxide radicals induced by solar UV-B radiation in Ulva canopies from southern Spain

    Directory of Open Access Journals (Sweden)

    Kai Bischof

    2003-09-01

    Full Text Available The generation of reactive oxygen species (ROS and scavenging of the superoxide radical by superoxide dismutase (SOD was studied in mat-like canopies of the green macroalga Ulva rotundata Bliding in a tidal brine pond system in southern Spain. Artificial canopies were covered with different cut-off filters, generating different radiation conditions. ROS and SOD were assessed after three days of exposure. ROS induced lipid peroxidation depended on the position of individual thalli within the canopy and on radiation conditions. Samples exposed to the full solar spectrum were most affected, whereas samples either exposed to photosynthetically active radiation (PAR alone or UV radiation without PAR exhibited fewer peroxidation products. The activity of SOD appeared to be controlled by the impinging UV-A and UV-B radiation and also increased in response to oxidative stress. The results provide evidence for additive effects of high PAR and UV-B under field conditions and support the previously proposed hypothesis that UV-B effects are mediated by an inhibition of the xanthophyll cycle, which increases ROS production and, consequently, causes oxidative damage to components of the photosynthetic machinery, such as proteins and pigments.

  11. Uranyl nitrate-exposed rat alveolar macrophages cell death: Influence of superoxide anion and TNF α mediators

    Energy Technology Data Exchange (ETDEWEB)

    Orona, N.S. [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); Tasat, D.R., E-mail: deborah.tasat@unsam.edu.ar [School of Science and Technology, National University of General Martín, Avda Gral Paz 5445 (1650) San Martín, Buenos Aires (Argentina); School of Dentistry, University of Buenos Aires, M. T. de Alvear 2142 (1122), Buenos Aires (Argentina)

    2012-06-15

    Uranium compounds are widely used in the nuclear fuel cycle, military and many other diverse industrial processes. Health risks associated with uranium exposure include nephrotoxicity, cancer, respiratory, and immune disorders. Macrophages present in body tissues are the main cell type involved in the internalization of uranium particles. To better understand the pathological effects associated with depleted uranium (DU) inhalation, we examined the metabolic activity, phagocytosis, genotoxicity and inflammation on DU-exposed rat alveolar macrophages (12.5–200 μM). Stability and dissolution of DU could differ depending on the dissolvent and in turn alter its biological action. We dissolved DU in sodium bicarbonate (NaHCO{sub 3} 100 mM) and in what we consider a more physiological vehicle resembling human internal media: sodium chloride (NaCl 0.9%). We demonstrate that uranyl nitrate in NaCl solubilizes, enters the cell, and elicits its cytotoxic effect similarly to when it is diluted in NaHCO{sub 3}. We show that irrespective of the dissolvent employed, uranyl nitrate impairs cell metabolism, and at low doses induces both phagocytosis and generation of superoxide anion (O{sub 2}{sup −}). At high doses it provokes the secretion of TNFα and through all the range of doses tested, apoptosis. We herein suggest that at DU low doses O{sub 2}{sup −} may act as the principal mediator of DNA damage while at higher doses the signaling pathway mediated by O{sub 2}{sup −} may be blocked, prevailing damage to DNA by the TNFα route. The study of macrophage functions after uranyl nitrate treatment could provide insights into the pathophysiology of uranium‐related diseases. -- Highlights: ► Uranyl nitrate effect on cultured macrophages is linked to the doses and independent of its solubility. ► At low doses uranyl nitrate induces generation of superoxide anion. ► At high doses uranyl nitrate provokes secretion of TNFα. ► Uranyl nitrate induces apoptosis through

  12. Titanium dioxide nanoparticles enhance production of superoxide anion and alter the antioxidant system in human osteoblast cells

    Science.gov (United States)

    Niska, Karolina; Pyszka, Katarzyna; Tukaj, Cecylia; Wozniak, Michal; Radomski, Marek Witold; Inkielewicz-Stepniak, Iwona

    2015-01-01

    Titanium dioxide (TiO2) nanoparticles (NPs) are manufactured worldwide for a variety of engineering and bioengineering applications. TiO2NPs are frequently used as a material for orthopedic implants. However, to the best of our knowledge, the biocompatibility of TiO2NPs and their effects on osteoblast cells, which are responsible for the growth and remodeling of the human skeleton, have not been thoroughly investigated. In the research reported here, we studied the effects of exposing hFOB 1.19 human osteoblast cells to TiO2NPs (5–15 nm) for 24 and 48 hours. Cell viability, alkaline phosphatase (ALP) activity, cellular uptake of NPs, cell morphology, superoxide anion (O2•−2) generation, superoxide dismutase (SOD) activity and protein level, sirtuin 3 (SIR3) protein level, correlation between manganese (Mn) SOD and SIR, total antioxidant capacity, and malondialdehyde were measured following exposure of hFOB 1.19 cells to TiO2NPs. Exposure of hFOB 1.19 cells to TiO2NPs resulted in: (1) cellular uptake of NPs; (2) increased cytotoxicity and cell death in a time- and concentration-dependent manner; (3) ultrastructure changes; (4) decreased SOD and ALP activity; (5) decreased protein levels of SOD1, SOD2, and SIR3; (6) decreased total antioxidant capacity; (7) increased O2•− generation; and (8) enhanced lipid peroxidation (malondialdehyde level). The linear relationship between the protein level of MnSOD and SIR3 and between O2•− content and SIR3 protein level was observed. Importantly, the cytotoxic effects of TiO2NPs were attenuated by the pretreatment of hFOB 1.19 cells with SOD, indicating the significant role of O2•− in the cell damage and death observed. Thus, decreased expression of SOD leading to increased oxidizing stress may underlie the nanotoxic effects of TiO2NPs on human osteoblasts. PMID:25709434

  13. Short-term hydro generation scheduling of Xiluodu and Xiangjiaba cascade hydropower stations using improved binary-real coded bee colony optimization algorithm

    International Nuclear Information System (INIS)

    Lu, Peng; Zhou, Jianzhong; Wang, Chao; Qiao, Qi; Mo, Li

    2015-01-01

    Highlights: • STHGS problem is decomposed into two parallel sub-problems of UC and ELD. • Binary coded BCO is used to solve UC sub-problem with 0–1 discrete variables. • Real coded BCO is used to solve ELD sub-problem with continuous variables. • Some heuristic repairing strategies are designed to handle various constraints. • The STHGS of Xiluodu and Xiangjiaba cascade stations is solved by IB-RBCO. - Abstract: Short-term hydro generation scheduling (STHGS) of cascade hydropower stations is a typical nonlinear mixed integer optimization problem to minimize the total water consumption while simultaneously meeting the grid requirements and other hydraulic and electrical constraints. In this paper, STHGS problem is decomposed into two parallel sub-problems of unit commitment (UC) and economic load dispatch (ELD), and the methodology of improved binary-real coded bee colony optimization (IB-RBCO) algorithm is proposed to solve them. Firstly, the improved binary coded BCO is used to solve the UC sub-problem with 0–1 discrete variables, and the heuristic repairing strategy for unit state constrains is applied to generate the feasible unit commitment schedule. Then, the improved real coded BCO is used to solve the ELD sub-problem with continuous variables, and an effective method is introduced to handle various unit operation constraints. Especially, the new updating strategy of DE/best/2/bin method with dynamic parameter control mechanism is applied to real coded BCO to improve the search ability of IB-RBCO. Finally, to verify the feasibility and effectiveness of the proposed IB-RBCO method, it is applied to solve the STHGS problem of Xiluodu and Xiangjiaba cascaded hydropower stations, and the simulating results are compared with other intelligence algorithms. The simulation results demonstrate that the proposed IB-RBCO method can get higher-quality solutions with less water consumption and shorter calculating time when facing the complex STHGS problem

  14. Deterministic and probabilistic interval prediction for short-term wind power generation based on variational mode decomposition and machine learning methods

    International Nuclear Information System (INIS)

    Zhang, Yachao; Liu, Kaipei; Qin, Liang; An, Xueli

    2016-01-01

    Highlights: • Variational mode decomposition is adopted to process original wind power series. • A novel combined model based on machine learning methods is established. • An improved differential evolution algorithm is proposed for weight adjustment. • Probabilistic interval prediction is performed by quantile regression averaging. - Abstract: Due to the increasingly significant energy crisis nowadays, the exploitation and utilization of new clean energy gains more and more attention. As an important category of renewable energy, wind power generation has become the most rapidly growing renewable energy in China. However, the intermittency and volatility of wind power has restricted the large-scale integration of wind turbines into power systems. High-precision wind power forecasting is an effective measure to alleviate the negative influence of wind power generation on the power systems. In this paper, a novel combined model is proposed to improve the prediction performance for the short-term wind power forecasting. Variational mode decomposition is firstly adopted to handle the instability of the raw wind power series, and the subseries can be reconstructed by measuring sample entropy of the decomposed modes. Then the base models can be established for each subseries respectively. On this basis, the combined model is developed based on the optimal virtual prediction scheme, the weight matrix of which is dynamically adjusted by a self-adaptive multi-strategy differential evolution algorithm. Besides, a probabilistic interval prediction model based on quantile regression averaging and variational mode decomposition-based hybrid models is presented to quantify the potential risks of the wind power series. The simulation results indicate that: (1) the normalized mean absolute errors of the proposed combined model from one-step to three-step forecasting are 4.34%, 6.49% and 7.76%, respectively, which are much lower than those of the base models and the hybrid

  15. Preliminary neutron diffraction analysis of challenging human manganese superoxide dismutase crystals.

    Science.gov (United States)

    Azadmanesh, Jahaun; Trickel, Scott R; Weiss, Kevin L; Coates, Leighton; Borgstahl, Gloria E O

    2017-04-01

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

  16. Reaction of hypotaurine or taurine with superoxide produces the organic peroxysulfonic acid peroxytaurine.

    Science.gov (United States)

    Grove, Roxanna Q; Karpowicz, Steven J

    2017-07-01

    Hypotaurine and taurine are amino acid derivatives and abundant molecules in many eukaryotes. The biological reaction in which hypotaurine is converted to taurine remains poorly understood. Here, hypotaurine and taurine were observed to react with superoxide anion in vitro to form the novel molecule peroxytaurine. In contrast, hypotaurine reacts with hydrogen peroxide to form taurine, but taurine does not react with hydrogen peroxide in vitro. Mass and NMR spectrometry as well as FTIR and Raman spectroscopy support the molecular characterization of peroxytaurine. Gravitometric and spectroscopy experiments suggest a stoichiometry of two superoxide anions reacting with one hypotaurine or two taurines. The newly identified molecule is a semi-stable, organic peroxysulfonic acid that may be an intermediate metabolite in taurine synthesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Superoxide dismutase from Trichuris ovis, inhibiton by benzimidazoles and pyrimidine derivatives

    Directory of Open Access Journals (Sweden)

    M. Sanchez-Moreno

    1992-01-01

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

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

    Science.gov (United States)

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

    1992-01-01

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

  19. Furin proteolytically processes the heparin-binding region of extracellular superoxide dismutase

    DEFF Research Database (Denmark)

    Bowler, Russell P; Nicks, Mike; Olsen, Dorte Aa

    2002-01-01

    Extracellular superoxide dismutase (EC-SOD) is an antioxidant enzyme that attenuates brain and lung injury from oxidative stress. A polybasic region in the carboxyl terminus distinguishes EC-SOD from other superoxide dismutases and determines EC-SOD's tissue half-life and affinity for heparin....... There are two types of EC-SOD that differ based on the presence or absence of this heparin-binding region. It has recently been shown that proteolytic removal of the heparin-binding region is an intracellular event (Enghild, J. J., Thogersen, I. B., Oury, T. D., Valnickova, Z., Hojrup, P., and Crapo, J. D...... of intracellular proteases implicate furin as a processing protease. In vitro experiments using furin and purified EC-SOD suggest that furin proteolytically cleaves EC-SOD in the middle of the polybasic region and then requires an additional carboxypeptidase to remove the remaining lysines and arginines...

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

    International Nuclear Information System (INIS)

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

    2014-01-01

    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

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

    Science.gov (United States)

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

    2000-09-15

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

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

    Science.gov (United States)

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

    2015-01-01

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

  3. Effect of Oxidative Damage on the Stability and Dimerization of Superoxide Dismutase 1

    OpenAIRE

    Petrov, Drazen; Daura, Xavier; Zagrovic, Bojan

    2016-01-01

    During their life cycle, proteins are subject to different modifications involving reactive oxygen species. Such oxidative damage to proteins may lead to the formation of insoluble aggregates and cytotoxicity and is associated with age-related disorders including neurodegenerative diseases, cancer, and diabetes. Superoxide dismutase 1 (SOD1), a key antioxidant enzyme in human cells, is particularly susceptible to such modifications. Moreover, this homodimeric metalloenzyme has been directly l...

  4. The superoxide scavenger TEMPOL induces urokinase receptor (uPAR expression in human prostate cancer cells

    Directory of Open Access Journals (Sweden)

    Francis Joseph

    2006-06-01

    Full Text Available Abstract There is little understanding of the effect that reactive oxygen metabolites have on cellular behavior during the processes of invasion and metastasis. These oxygen metabolites could interact with a number of targets modulating their function such as enzymes involved in basement membrane dissolution, adhesion molecules involved in motility or receptors involved in proliferation. We investigated the effect of increased scavenging of superoxide anions on the expression of the urokinase receptor (uPAR in PC-3M human prostate cancer cells. Urokinase receptor is a GPI-linked cell surface molecule which mediates multiple functions including adhesion, proliferation and pericellular proteolysis. Addition of the superoxide scavenger 4-hydroxy-2,2,6,6-tetramethylpiperidinyloxy (TEMPOL to PC-3M cultures stimulated expression of uPAR protein peaking between 48 and 72 hours. Cell surface expression of the uPAR was also increased. Surprisingly, uPAR transcript levels increased only slightly and this mild increase did not coincide with the striking degree of protein increase. This disparity indicates that the TEMPOL effect on uPAR occurs through a post-transcriptional mechanism. TEMPOL presence in PC-3M cultures reduced intracellular superoxide-type species by 75% as assayed by NBT dye conversion; however this reduction significantly diminished within hours following TEMPOL removal. The time gap between TEMPOL treatment and peak uPAR protein expression suggests that reduction of reactive oxygen metabolites in prostate cancer cells initiates a multistep pathway which requires several hours to culminate in uPAR induction. These findings reveal a novel pathway for uPAR regulation involving reactive oxygens such as superoxide anion.

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

    Science.gov (United States)

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

    2017-08-01

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

  6. Functional and Immunological Analyses of Superoxide Dismutases and Other Spore-Associated Proteins of Bacillus anthracis

    Science.gov (United States)

    2008-08-20

    L., S. Hibbs, P. Tsai, G. L. Cao, and G. M. Rosen . 2005. Role of superoxide in the germination of Bacillus anthracis endospores. FEMS Microbiol...178:7994-8001. 42. Cohen, S., I. Mendelson, Z. Altboum, D. Kobiler, E. Elhanany, T. Bino, M. Leitner, I. Inbar, H. Rosenberg, Y. Gozes, R. Barak ...K. W. Raines, G. L. Cao, S. Hibbs, P. Tsai, L. Baillie, G. M. Rosen , and A. S. Cross. 2007. Protective role of Bacillus anthracis exosporium in

  7. Brain superoxide anion formation in immature rats during seizures: Protection by selected compounds

    Czech Academy of Sciences Publication Activity Database

    Folbergrová, Jaroslava; Otáhal, Jakub; Druga, Rastislav

    2012-01-01

    Roč. 233, č. 1 (2012), s. 421-429 ISSN 0014-4886 R&D Projects: GA ČR GA309/08/0292; GA ČR GAP303/10/0999 Institutional research plan: CEZ:AV0Z50110509 Keywords : immature rats * DL-homocysteic acid-induced seizures * superoxide anion * SOD mimetics * protection * Fluoro-Jade B staining * brain damage Subject RIV: FH - Neurology Impact factor: 4.645, year: 2012

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

    Energy Technology Data Exchange (ETDEWEB)

    Muid, Khandaker Ashfaqul; Karakaya, Hüseyin Çaglar; Koc, Ahmet, E-mail: ahmetkoc@iyte.edu.tr

    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.

  9. Short–Term Exposure to Electromagnetic Fields Generated by Mobile Phone Jammers Decreases the Fasting Blood Sugar in Adult Male Rats

    Directory of Open Access Journals (Sweden)

    Shekoohi Shooli F.

    2016-03-01

    Full Text Available Background: Substantial evidence indicates that exposure to electromagnetic fields (EMF above certain levels can affect human health through triggering some biological responses. According to WHO, short-term exposure to EMF at the levels present in the home/environment do not cause any apparent detrimental effects in healthy individuals. However, now, there is a debate on whether long-term exposure to low level EMF can evoke detrimental biological responses. Although based on the Communications Act of 1934, selling, advertising, using, or importing mobile jammers which block cell phone calls and text messages are illegal acts, in some countries these devices are being used for security purpose and for prevention of cheating during examinations. Methods: In this study 30 male Wistar rats were randomly divided into 3 groups of 10 each. The control group received no radiation. The sham exposure group was exposed to a switched-off jammer device. After fasting for 12 hours, the exposure group was exposed to EMFs at a distance of 50 cm from the jammer. Blood samples were collected from the tail vein after 24, 48 and72 hours and fasting blood sugar was measured by using a common blood glucose monitor (BIONIME GM110, Taiwan. The significance level was considered 5% and SPSS Ver. 21 was used for statistical analysis. The data were analyzed by ANOVA followed by Tukey’s test. Results: A statistically significant difference was observed between blood sugar level in the control and exposure groups after 24, 48 and 72 hours of continuous irradiation (p values were <0.001, <0.001 and 0.002, respectively. No significant difference was found between the level of fasting blood sugar in control and sham groups. Conclusion: Short-term exposure to electromagnetic field generated by mobile phone jammer can reduce blood sugar level in adult male rats. These findings, in contrast with our previous results, lead us to this conclusion that the use of these signal

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

    Science.gov (United States)

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

    2008-01-01

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

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

    Science.gov (United States)

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

    2008-04-18

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

  12. Ultimate disposal of radioactive waste - Long-term safe containment. Also a contribution to giving concrete shape to our reponsibility towards the life of future generations

    International Nuclear Information System (INIS)

    Naeser, H.W.; Oberpottkamp, U.

    1995-01-01

    A fundamental issue arising in connection with the plan approval procedure for the construction and operation of radwaste repositories is the question whether the documentation submitted in evidence of appropriate precaution being taken according to the state of the art in science and technology to prevent damage to the population and the environment, is to include evidence that the precautions envisaged and their efficiency can be maintained by the operator over a prolonged period of time. The opinion of the authors is that demanding such evidence of long-term safe containment of hazardous waste is in agreement with Art. 20 a GG (German Constitution) and is to be given for the full period of time that is accessible to assessment and computation using the state-of-the-art means and technology, yielding reliable scientific results void of any data of a speculative nature. Computed evidence is to be submitted for this period of time in compliance with the means and principles given in section 45 StrlSchV (Radiation Protection Ordinance). The article thus is a contribution to giving more concrete shape to the responsibility towards future generations. (orig.) [de

  13. Loss of the ability to generate large burst-forming unit-like megakaryocytic colonies from thawed cord blood in semisolid cultures after short term suspension culture.

    Science.gov (United States)

    Eskola, M; Bäckman, S; Möttönen, S; Kekomäki, R

    2015-04-01

    Total colony-forming cells from thawed cord blood units (CBUs) include megakaryocytic colony-forming units (CFU-Mks), which survive the freezing process. The aim of this study was to evaluate whether different megakaryocytic progenitors from unseparated CBUs survive the freezing process and a short-term liquid culture. Thawed samples of CBUs were cultured in liquid medium. During the cultures, serial samples were drawn to assess the growth of different megakaryocytic progenitors in a semisolid collagen medium with identical cytokines as in the liquid medium. Megakaryocytic cells were detected using immunohistochemistry and flow cytometry. In suspension culture, the megakaryocytic progenitors almost completely lost the ability to generate large (burst-forming unit-like, BFU-like) megakaryocytic colonies in semisolid cultures (large colonies, median count per chamber d0: 7.25 vs. d7: 1.5; P culture in suspension resulted in the decline of small colonies as well (d7: 16.0 vs. d14: 5.75; P = 0.0088). Total CFU-Mk count declined from 23.3 (range 12.5-34.0) at d0 to 7.25 (range 1.0-13.5) at d14 (P culture after a short suspension culture. Small CFU-Mks were observed throughout the cultures. It may be that the BFU-Mk colonies matured and acquired CFU-Mk behaviour. © 2014 International Society of Blood Transfusion.

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

    Science.gov (United States)

    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.

  15. Myocardial capillary permeability after regional ischemia and reperfusion in the in vivo canine heart. Effect of superoxide dismutase

    DEFF Research Database (Denmark)

    Svendsen, J H; Bjerrum, P J; Haunsø, S

    1991-01-01

    This study assesses the effect of the superoxide anion scavenger superoxide dismutase on myocardial capillary permeability-surface area (PS) products for small hydrophilic molecules after ischemia and reperfusion. Open-chest dogs underwent a 20-minute occlusion of the left anterior descending...... the start of reperfusion. In 13 dogs, no scavenger treatment was given (nonprotected control group), whereas eight dogs were treated systemically with 15,000 units/kg superoxide dismutase during 1 hour, starting 20 minutes before ischemia. In the control group, three dogs developed reperfusion ventricular...

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

    International Nuclear Information System (INIS)

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

    2013-01-01

    Graphical abstract: Schematic representation of the assembly process of SOD/GNPs-CS-IL/GCE. Highlights: ► SOD was immobilized in gold nanoparticles-chitosan-ionic liquid (GNPs-CS-IL) film. ► The biosensor was constructed by one-step ultrasonic electrodeposition of GNPs-CS-IL onto GCE. ► The biosensor showed excellent analytical performance for O 2 · − real-time analysis. - Abstract: 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 0.257 V was observed at SOD/GNPs-CS-IL/GCE in phosphate buffer solution (PBS, 0.1 M, 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 ( 3 nM), low detection limit (1.7 nM), 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.

  17. Oxidative status, in vitro iron-induced lipid oxidation and superoxide dismutase, catalase and glutathione peroxidase activities in rhea meat.

    Science.gov (United States)

    Terevinto, A; Ramos, A; Castroman, G; Cabrera, M C; Saadoun, A

    2010-04-01

    Rhea (Rhea americana) muscles Obturatorius medialis (OM) Iliotibialis lateralis (IL) and Iliofibularis (I), obtained from farmed animals, were evaluated regarding their oxidative/antioxidant status. The mean level of thiobarbituric acid reactive substances (TBARS) expressed as malonaldehyde (MDA) content was of 0.84 mg MDA/kg wet tissue for the three muscles. TBARS level was significantly higher in IL than OM and I, with the two latter showing similar levels. The mean level of carbonyl proteins expressed as dinitrophenylhydrazine (DNPH) was 1.59 nmol DNPH mg(-1). Carbonyl protein levels were significantly different (POM>I). Iron-induced TBARS generation was not significantly different between the three muscles at any time, nor for each muscle during the 5 h of the experiment. Superoxide dismutase activity in IL muscle was significantly higher (P<0.05) than in I muscle. However, the difference between IL and OM muscles was not significant. The differences between the three muscles became not significant when the results were expressed by mg of protein contained in the extract, instead by g of wet tissue. No differences were found for catalase (micromol of discomposed H(2)O(2) min(-1) g(-1) wet tissue or by mg of protein contained in the extract) and glutathione peroxidase (micromol ol of oxidized NADPH min(-1) g(-1) of wet tissue or by mg of protein contained in the extract) activities between the three muscles. 2009 Elsevier Ltd. All rights reserved.

  18. Tolerance of spermatogonia to oxidative stress is due to high levels of Zn and Cu/Zn superoxide dismutase.

    Directory of Open Access Journals (Sweden)

    Fritzie T Celino

    Full Text Available BACKGROUND: Spermatogonia are highly tolerant to reactive oxygen species (ROS attack while advanced-stage germ cells such as spermatozoa are much more susceptible, but the precise reason for this variation in ROS tolerance remains unknown. METHODOLOGY/PRINCIPAL FINDINGS: Using the Japanese eel testicular culture system that enables a complete spermatogenesis in vitro, we report that advanced-stage germ cells undergo intense apoptosis and exhibit strong signal for 8-hydroxy-2'-deoxyguanosine, an oxidative DNA damage marker, upon exposure to hypoxanthine-generated ROS while spermatogonia remain unaltered. Activity assay of antioxidant enzyme, superoxide dismutase (SOD and Western blot analysis using an anti-Copper/Zinc (Cu/Zn SOD antibody showed a high SOD activity and Cu/Zn SOD protein concentration during early spermatogenesis. Immunohistochemistry showed a strong expression for Cu/Zn SOD in spermatogonia but weak expression in advanced-stage germ cells. Zn deficiency reduced activity of the recombinant eel Cu/Zn SOD protein. Cu/Zn SOD siRNA decreased Cu/Zn SOD expression in spermatogonia and led to increased oxidative damage. CONCLUSIONS/SIGNIFICANCE: These data indicate that the presence of high levels of Cu/Zn SOD and Zn render spermatogonia resistant to ROS, and consequently protected from oxidative stress. These findings provide the biochemical basis for the high tolerance of spermatogonia to oxidative stress.

  19. The role of mitochondrial superoxide anion (O2-) on physiological aging in C57BL/6J mice

    International Nuclear Information System (INIS)

    Miyazawa, Masaki; Ishii, Takamasa; Yasuda, Kayo; Onouchi, Hiromi; Ishii, Naoaki; Noda, Setsuko; Hartman, Philip S.

    2009-01-01

    Much attention has been focused on the mitochondrial superoxide anion (O 2 - ), which is also a critical free radical produced by ionizing radiation. The specific role of the mitochondrial O 2 - on physiological aging in mammals is still nuclear despite wide-spread evidence that oxidative stress is involved in aging and age-related diseases. The major endogenous source of O 2 - is generated as a byproduct of energy metabolism from mitochondria. In order to better understand how O 2 - relates to metazoan aging, we have comprehensively examined age-related changes in the levels of oxidative damage, mitochondrial O 2 - production, mitochondrial antioxidant enzyme activity and apoptosis induction in key organs of an inbred mouse strain (C57BL/6J). Oxidative damage accumulated and excess apoptosis occurred in the brain, oculus and kidney with aging, but comparatively little occurred in the heart and muscle. These rates are correlated with O 2 - levels. Mitochondrial O 2 - production levels increased with aging in the brain, oculus and kidney, and did not significantly increased in the heart and muscle. In contrast to O 2 - production, mitochondrial SOD activities increased in heart and muscle, and remained unchanged in the brain, oculus and kidney with aging. These results suggest that O 2 - production has high organ specificity, and oxidative damage by O 2 - from mitochondria mediated apoptosis can lead to organ atrophy and physiological dysfunction. In addition, O 2 - from mitochondria plays a core role in physiological aging. (author)

  20. The role of mitochondrial superoxide anion (O2(-)) on physiological aging in C57BL/6J mice.

    Science.gov (United States)

    Miyazawa, Masaki; Ishii, Takamasa; Yasuda, Kayo; Noda, Setsuko; Onouchi, Hiromi; Hartman, Philip S; Ishii, Naoaki

    2009-01-01

    Much attention has been focused on the mitochondrial superoxide anion (O2(-)), which is also a critical free radial produced by ionizing radiation. The specific role of the mitochondrial O2(-) on physiological aging in mammals is still unclear despite wide-spread evidence that oxidative stress is involved in aging and age-related diseases. The major endogenous source of O2(-) is generated as a byproduct of energy metabolism from mitochondria. In order to better understand how O2(-)relates to metazoan aging, we have comprehensively examined age-related changes in the levels of oxidative damage, mitochondrial O2(-) production, mitochondrial antioxidant enzyme activity and apoptosis induction in key organs of an inbred mouse strain (C57BL/6J). Oxidative damage accumulated and excess apoptosis occurred in the brain, oculus and kidney with aging, but comparatively little occurred in the heart and muscle. These rates are correlated with O2(-) levels. Mitochondrial O2(-) production levels increased with aging in the brain, oculus and kidney, and did not significantly increased in the heart and muscle. In contrast to O2(-) production, mitochondrial SOD activities increased in heart and muscle, and remained unchanged in the brain, oculus and kidney with aging. These results suggest that O2(-) production has high organ specificity, and oxidative damage by O2(-) from mitochondria mediated apoptosis can lead to organ atrophy and physiological dysfunction. In addition, O2(-) from mitochondria plays a core role in physiological aging.

  1. Identification of Manganese Superoxide Dismutase from Sphingobacterium sp. T2 as a Novel Bacterial Enzyme for Lignin Oxidation.

    Science.gov (United States)

    Rashid, Goran M M; Taylor, Charles R; Liu, Yangqingxue; Zhang, Xiaoyang; Rea, Dean; Fülöp, Vilmos; Bugg, Timothy D H

    2015-10-16

    The valorization of aromatic heteropolymer lignin is an important unsolved problem in the development of a biomass-based biorefinery, for which novel high-activity biocatalysts are needed. Sequencing of the genomic DNA of lignin-degrading bacterial strain Sphingobacterium sp. T2 revealed no matches to known lignin-degrading genes. Proteomic matches for two manganese superoxide dismutase proteins were found in partially purified extracellular fractions. Recombinant MnSOD1 and MnSOD2 were both found to show high activity for oxidation of Organosolv and Kraft lignin, and lignin model compounds, generating multiple oxidation products. Structure determination revealed that the products result from aryl-Cα and Cα-Cβ bond oxidative cleavage and O-demethylation. The crystal structure of MnSOD1 was determined to 1.35 Å resolution, revealing a typical MnSOD homodimer harboring a five-coordinate trigonal bipyramidal Mn(II) center ligated by three His, one Asp, and a water/hydroxide in each active site. We propose that the lignin oxidation reactivity of these enzymes is due to the production of a hydroxyl radical, a highly reactive oxidant. This is the first demonstration that MnSOD is a microbial lignin-oxidizing enzyme.

  2. Kinetics and mechanism of superoxide radical reactions with some biologically important compounds in aqueous solutions. Pulse radiolysis

    Science.gov (United States)

    Revina, A. A.; Amiragova, M. I.; Volod'ko, V. V.; Vannikov, A. V.

    Microsecond pulse radiolysis of oxygenated aqueous solutions containing 0.02 mol dm -3 sodium formate and 2 mmol dm -3 phosphate buffer at pH 7 was used to generate superoxide anion radicals. The influence of some biologically important compounds upon the rate of O ⨪2 decay was monitored spectrophotometrically in the range of 245-300 nm. Hematoporphyrin (HP), hemin C (HC), catalase (Cat), cobalt sulfophthalocyanine (CoTSPc) were studied. Among the investigated compounds only Cat was found to show a high catalytic efficiency towards the self-decay of O ⨪2. A red shift of O ⨪2 absorption band and slowing down of its decay were observed to take place by adding HP or CoTSPc to the solutions containing formate ions in excess. This effect is associated with the formation of a transient superoxo-complex. An appearance of an intermediate species with absorption maxima at 350 nm and half-life of about 2s was observed to accompany the superoxo-complex of CoTSPc decay. In the aerated solution of HP the intensity of absorbance at 260 nm was found to be independent of the presence of formate ions.

  3. Kinetics and mechanism of superoxide radical reactions with some biologically important compounds in aqueous solutions. Pulse radiolysis

    International Nuclear Information System (INIS)

    Revina, A.A.; Volod'ko, V.V.; Vannikov, A.V.

    1989-01-01

    Microsecond pulse radiolysis of oxygenated aqueous solutions containing 0.02 mol dm -3 sodium formate and 2 mmol dm -3 phosphate buffer at pH 7 was used to generate superoxide anion radicals. The influence of some biologically important compounds upon the rate of O 2 .-bar decay as monitored spectrophotometrically in the range of 245-300 nm. Hematoporphyrin (HP), hemin C (HC), catalase (Cat), cobalt sulfophthalocyanine (CoTSPc) were studied. Among the investigated compounds only Cat was found to show a high catalytic efficiency towards the self-decay of O 2 .-bar . A red shift of 0 2 .-bar absorption band and slowing down of its decay were observed to take place by adding HP or CoTSPc to the solutions containing formate ions in excess. This effect is associated with the formation of a transient superoxo-complex. An appearance of an intermediate species with absorption maxima at 350 nm and half-life of about 2 s was observed to accompany the superoxo-complex of CoTSPc decay. In the aerated solution of HP the intensity of absorbance at 260 nm was found to be independent of the presence of formate ions. (author)

  4. Resveratrol suppresses ethanol stress in winery and bottom brewery yeast by affecting superoxide dismutase, lipid peroxidation and fatty acid profile.

    Science.gov (United States)

    Gharwalova, Lucia; Sigler, Karel; Dolezalova, Jana; Masak, Jan; Rezanka, Tomas; Kolouchova, Irena

    2017-11-03

    Mid-exponential cultures of two traditional biotechnological yeast species, winery Saccharomyces cerevisiae and the less ethanol tolerant bottom-fermenting brewery Saccharomyces pastorianus, were exposed to different concentrations of added ethanol (3, 5 and 8%) The degree of ethanol-induced cell stress was assessed by measuring the cellular activity of superoxide dismutase (SOD), level of lipid peroxidation products, changes in cell lipid content and fatty acid profile. The resveratrol as an antioxidant was found to decrease the ethanol-induced rise of SOD activity and suppress the ethanol-induced decrease in cell lipids. A lower resveratrol concentration (0.5 mg/l) even reduced the extent of lipid peroxidation in cells. Resveratrol also alleviated ethanol-induced changes in cell lipid composition in both species by strongly enhancing the proportion of saturated fatty acids and contributing thereby to membrane stabilization. Lower resveratrol concentrations could thus diminish the negative effects of ethanol stress on yeast cells and improve their physiological state. These effects may be utilized to enhance yeast vitality in high-ethanol-producing fermentations or to increase the number of yeast generations in brewery.

  5. Reactive oxygen species on bone mineral density and mechanics in Cu,Zn superoxide dismutase (Sod1) knockout mice

    International Nuclear Information System (INIS)

    Smietana, Michael J.; Arruda, Ellen M.; Faulkner, John A.; Brooks, Susan V.; Larkin, Lisa M.

    2010-01-01

    Research highlights: → Reactive oxygen species (ROS) are considered to be a factor in the onset of a number of age-associated conditions, including loss of BMD. → Cu,Zn-superoxide dismutase (Sod1) deficient mice have increased ROS, reduced bone mineral density, decreased bending stiffness, and decreased strength compared to WT controls. → Increased ROS caused by the deficiency of Sod1, may be responsible for the changes in BMD and bone mechanics and therefore represent an appropriate model for studying mechanisms of age-associated bone loss. -- Abstract: Reactive oxygen species (ROS) play a role in a number of degenerative conditions including osteoporosis. Mice deficient in Cu,Zn-superoxide dismutase (Sod1) (Sod1 -/- mice) have elevated oxidative stress and decreased muscle mass and strength compared to wild-type mice (WT) and appear to have an accelerated muscular aging phenotype. Thus, Sod1 -/- mice may be a good model for evaluating the effects of free radical generation on diseases associated with aging. In this experiment, we tested the hypothesis that the structural integrity of bone as measured by bending stiffness (EI; N/mm 2 ) and strength (MPa) is diminished in Sod1 -/- compared to WT mice. Femurs were obtained from male and female WT and Sod1 -/- mice at 8 months of age and three-point bending tests were used to determine bending stiffness and strength. Bones were also analyzed for bone mineral density (BMD; mg/cc) using micro-computed tomography. Femurs were approximately equal in length across all groups, and there were no significant differences in BMD or EI with respect to gender in either genotype. Although male and female mice demonstrated similar properties within each genotype, Sod1 -/- mice exhibited lower BMD and EI of femurs from both males and females compared with gender matched WT mice. Strength of femurs was also lower in Sod1 -/- mice compared to WT as well as between genders. These data indicate that increased oxidative stress

  6. The impact of heterologous catalase expression and superoxide dismutase overexpression on enhancing the oxidative resistance in Lactobacillus casei.

    Science.gov (United States)

    Lin, Jinzhong; Zou, Yexia; Cao, Kunlin; Ma, Chengjie; Chen, Zhengjun

    2016-05-01

    Two heme-dependent catalase genes were amplified from genomic DNA of Lactobacillus plantarum WCFS1 (KatE1) and Lactobacillus brevis ATCC 367 (KatE2), respectively, and a manganese-containing superoxide dismutase from Lactobacillus casei MCJΔ1 (MnSOD) were cloned into plasmid pELX1, yielding pELX1-KatE1, pELX1-KatE2 and pELX1-MnSOD, then the recombinant plasmids were transferred into L. casei MCJΔ1. The strains of L. casei MCJΔ1/pELX1-KatE1 and L. casei MCJΔ1/pELX1-KatE2 were tolerant at 2 mM H2O2. The survival rates of L. casei MCJΔ1/pELX1-KatE1 and L. casei MCJΔ1/pELX1-KatE2 were 270-fold and 300-fold higher than that of the control strain on a short-term H2O2 exposure, and in aerated condition, the survival cells counts were 146- and 190-fold higher than that of the control strain after 96 h of incubation. Furthermore, L. casei MCJΔ1/pELX1-MnSOD was the best in three recombinants which was superior in the living cell viability during storage when co-storage with Lactobacillus delbrueckii subsp. lactis LBCH-1.

  7. Superoxide radical and UV irradiation in ultrasound assisted oxidative desulfurization (UAOD): A potential alternative for greener fuels

    Science.gov (United States)

    Chan, Ngo Yeung

    stream from becoming reactive or even explosive. High energy consumption is another drawback in the UAOD process. A typical 10 minutes ultrasonication applied in the UAOD process to achieve 95% desulfurization for 20g of diesel requires 450 kJ of energy, which is equivalent to approximately 50% of the energy that can be provided by the treated diesel. This great expenditure of energy is impractical for industries to adopt. In this study, modifications of the UAOD process, including the application of superoxide and selection of catalysts, were applied to lower the oxidant dosage and to improve the applicability towards heavy-distillates such as residual oil. The results demonstrated that the new system required 80% less oxidant as compared to previous generations of UAOD process without the loss of desulfurization efficiency. The new system demonstrated its suitability towards desulfurizing commercial mid-distillates including jet fuels, marine gas oil and sour diesel. This process also demonstrated a new method to desulfurize residual oil with high desulfurization yields. The new process development has been supported by Eco Energy Solutions Inc., Reno, Nevada and Intelligent Energy Inc., Long Beach, California. A feasibility study on UV assisted desulfurization by replacing ultrasound with UV irradiation was also conducted. The study demonstrated that the UV assisted desulfurization process consumes 90% less energy than the comparable process using ultrasonication. These process modifications demonstrated over 98% desulfurization efficiency on diesel oils and more than 75% on residual oils with significantly less oxidant and energy consumption. Also the feasibility to desulfurize commercial sour heavy oil was demonstrated. Based on the UAOD process and the commercialized modifications by Wan and Cheng, the feasible applications of superoxide and UV irradiation in the UAOD process could provide deep-desulfurization on various fuels with practical cost.

  8. Design of a New Near-Infrared Ratiometric Fluorescent Nanoprobe for Real-Time Imaging of Superoxide Anions and Hydroxyl Radicals in Live Cells and in Situ Tracing of the Inflammation Process in Vivo.

    Science.gov (United States)

    Liu, Rongjun; Zhang, Liangliang; Chen, Yunyun; Huang, Zirong; Huang, Yong; Zhao, Shulin

    2018-04-03

    The superoxide anion (O 2 •- ) and hydroxyl radical ( • OH) are important reactive oxygen species (ROS) used as biomarkers in physiological and pathological processes. ROS generation is closely related to the development of a variety of inflammatory diseases. However, the changes of ROS are difficult to ascertain with in situ tracing of the inflammation process by real-time monitoring, owing to the short half-lives of ROS and high tissue autofluorescence in vivo. Here we developed a new near-infrared (NIR) ratiometric fluorescence imaging approach by using a Förster resonance energy transfer (FRET)-based ratiometric fluorescent nanoprobe for real-time monitoring of O 2 •- and • OH generation and also by using in situ tracing of the inflammation process in vivo. The proposed nanoprobe was composed of PEG functionalized GQDs as the energy donor connecting to hydroIR783, serving as both the O 2 •- / • OH recognizing ligand and the energy acceptor. The nanoprobe not only exhibited a fast response to O 2 •- and • OH but also presented good biocomapatibility as well as a high photostability and signal-to-noise ratio. We have demonstrated that the proposed NIR ratiometric fluorescent nanoprobe can monitor the changes of O 2 •- and • OH in living RAW 264.7 cells via a drug mediating inflammation model and further realized visual monitoring of the change of O 2 •- and • OH in mice for in situ tracing of the inflammation process. Our design may provide a new paradigm for long-term and real-time imaging applications for in vivo tracing of the pathological process related to the inflammatory diseases.

  9. Mitochondrial localization of fission yeast manganese superoxide dismutase is required for its lysine acetylation and for cellular stress resistance and respiratory growth

    International Nuclear Information System (INIS)

    Takahashi, Hidekazu; Suzuki, Takehiro; Shirai, Atsuko; Matsuyama, Akihisa; Dohmae, Naoshi; Yoshida, Minoru

    2011-01-01

    Research highlights: → Fission yeast manganese superoxide dismutase (MnSOD) is acetylated. → The mitochondrial targeting sequence (MTS) is required for the acetylation of MnSOD. → The MTS is not crucial for MnSOD activity, but is important for respiratory growth. → Posttranslational regulation of MnSOD differs between budding and fission yeast. -- Abstract: Manganese-dependent superoxide dismutase (MnSOD) is localized in the mitochondria and is important for oxidative stress resistance. Although transcriptional regulation of MnSOD has been relatively well studied, much less is known about the protein's posttranslational regulation. In budding yeast, MnSOD is activated after mitochondrial import by manganese ion incorporation. Here we characterize posttranslational modification of MnSOD in the fission yeast Schizosaccharomyces pombe. Fission yeast MnSOD is acetylated at the 25th lysine residue. This acetylation was diminished by deletion of N-terminal mitochondrial targeting sequence, suggesting that MnSOD is acetylated after import into mitochondria. Mitochondrial localization of MnSOD is not essential for the enzyme activity, but is crucial for oxidative stress resistance and growth under respiratory conditions of fission yeast. These results suggest that, unlike the situation in budding yeast, S. pombe MnSOD is already active even before mitochondrial localization; nonetheless, mitochondrial localization is critical to allow the cell to cope with reactive oxygen species generated inside or outside of mitochondria.

  10. Role of catalase and superoxide dismutase activities on oxidative stress in the brain of a phenylketonuria animal model and the effect of lipoic acid.

    Science.gov (United States)

    Moraes, Tarsila Barros; Jacques, Carlos Eduardo Diaz; Rosa, Andrea Pereira; Dalazen, Giovana Reche; Terra, Melaine; Coelho, Juliana Gonzalez; Dutra-Filho, Carlos Severo

    2013-03-01

    Phenylketonuria (PKU) is an inherited metabolic disorder caused by deficiency of phenylalanine hydroxylase which leads to accumulation of phenylalanine and its metabolites in tissues of patients with severe neurological involvement. Recently, many studies in animal models or patients have reported the role of oxidative stress in PKU. In the present work we studied the effect of lipoic acid against oxidative stress in rat brain provoked by an animal model of hyperphenylalaninemia (HPA), induced by repetitive injections of phenylalanine and α-methylphenylalanine (a phenylalanine hydroxylase inhibitor) for 7 days, on some oxidative stress parameters. Lipoic acid prevented alterations on catalase (CAT) and superoxide dismutase (SOD), and the oxidative damage of lipids, proteins, and DNA observed in HPA rats. In addition, lipoic acid diminished reactive species generation compared to HPA group which was positively correlated to SOD/CAT ratio. We also observed that in vitro Phe inhibited CAT activity while phenyllactic and phenylacetic acids stimulated superoxide dismutase activity. These results demonstrate the efficacy of lipoic acid to prevent oxidative stress induced by HPA model in rats. The possible benefits of lipoic acid administration to PKU patients should be considered.

  11. Fluconazole and amphotericin-B resistance are associated with increased catalase and superoxide dismutase activity in Candida albicans and Candida dubliniensis

    Directory of Open Access Journals (Sweden)

    Carlos Eduardo Blanco Linares

    2013-12-01

    Full Text Available Introduction Candida dubliniensis, a new species of Candida that has been recovered from several sites in healthy people, has been associated with recurrent episodes of oral candidiasis in AIDS and HIV-positive patients. This species is closely related to C. albicans. The enzymatic activity of C. dubliniensis in response to oxidative stress is of interest for the development of drugs to combat C. dubliniensis. Methods Fluconazole- and amphotericin B-resistant strains were generated as described by Fekete-Forgács et al. (2000. Superoxide dismutase (SOD and catalase assays were performed as described by McCord and Fridovich (1969 and Aebi (1984, respectively. Results We demonstrated that superoxide dismutase (SOD and catalase activities were significantly higher (p<0.05 in the fluconazole- and amphotericin B-resistant strains of C. dubliniensis and C. albicans than in the sensitive strains. The catalase and SOD activities were also significantly (p<0.01 higher in the sensitive and resistant C. albicans strains than in the respective C. dubliniensis strains. Conclusions These data suggest that C. albicans is better protected from oxidative stress than C. dubliniensis and that fluconazole, like amphotericin B, can induce oxidative stress in Candida; oxidative stress induces an adaptive response that results in a coordinated increase in catalase and SOD activities.

  12. Effects of Deep Water Source-Sink Terms in 3rd generation Wave Model SWAN using different wind data in Black Sea

    Science.gov (United States)

    Kirezci, Cagil; Ozyurt Tarakcioglu, Gulizar

    2016-04-01

    Coastal development in Black Sea has increased in recent years. Therefore, careful monitoring of the storms and verification of numerical tools with reliable data has become important. Previous studies by Kirezci and Ozyurt (2015) investigated extreme events in Black Sea using different wind datasets (NCEP's CFSR and ECMWF's operational datasets) and different numerical tools (SWAN and Wavewatch III). These studies showed that significant effect to results is caused by the deep water source-sink terms (wave growth by wind, deep water dissipation of wave energy (whitecapping) and deep water non-linear wave-wave interactions). According to Timmermans(2015), uncertainty about wind forcing and the process of nonlinear wave-wave interactions are found to be dominant in numerical wave modelling. Therefore, in this study deep water source and sink term solution approaches of 3rd generation numerical tool (SWAN model) are tested, validated and compared using the selected extreme storms in Black Sea. 45 different storms and storm like events observed in Black Sea between years 1994-1999 are selected to use in the models. The storm selection depends on the instrumental wave data (significant wave heights, mean wave period and mean wave direction) obtained in NATO-TU Waves project by the deep water buoy measurements at Hopa, Sinop, Gelendzhik, and wind data (mean and peak wind speeds, storm durations) of the regarding events. 2 different wave growth by wind with the corresponding deep water dissipation terms and 3 different wave -wave interaction terms of SWAN model are used in this study. Wave growth by wind consist of two parts, linear growth which is explained by Cavaleri and Malanotte-Rizzoli(1981),and dominant exponential growth. There are two methods in SWAN model for exponential growth of wave, first one by Snyder et al. (1981), rescaled in terms of friction velocity by Komen et. al (1984) which is derived using driving wind speed at 10m elevation with related drag

  13. Autoradiographic evidence for methamphetamine-induced striatal dopaminergic loss in mouse brain: attenuation in CuZn-superoxide dismutase transgenic mice.

    Science.gov (United States)

    Hirata, H; Ladenheim, B; Carlson, E; Epstein, C; Cadet, J L

    1996-04-01

    Methamphetamine (METH) has long-lasting neurotoxic effects on the nigrostriatal dopamine (DA) system of rodents. METH-induced neurotoxicity is thought to involve release of DA in presynaptic DA terminals, which is associated with increased formation of oxygen-based free radicals. We have recently shown that METH-induced striatal DA depletion is attenuated in transgenic (Tg) mice that express the human CuZn-superoxide dismutase (SOD) enzyme. That study did not specifically address the issue of loss of DA terminals. In the present study, we have used receptor autoradiographic studies of [(125)I]RTI-121-labeled DA uptake sites to evaluate the effects of several doses of METH on striatal DA terminals of Non-Tg as well as of heterozygous and homozygous SOD-Tg mice. In Non-Tg mice, METH caused decreases in striatal DA uptake sites in a dose-dependent fashion. The loss of DA terminals was more prominent in the lateral region than in the medial subdivisions of the striatum. In SOD-Tg mice, the loss of DA terminals caused by METH was attenuated in a gene dosage-dependent fashion, with the homozygous mice showing the greatest protection. Female mice were somewhat more resistant than male mice against these deleterious effects of METH. These results provide further evidence for a role of superoxide radicals in the long-term effects of METH. They also suggest the notion of a gender-specific handling of oxidative stress.

  14. Neuroprotection from NMDA excitotoxic lesion by Cu/Zn superoxide dismutase gene delivery to the postnatal rat brain by a modular protein vector

    Science.gov (United States)

    Peluffo, Hugo; Acarin, Laia; Arís, Anna; González, Pau; Villaverde, Antoni; Castellano, Bernardo; González, Berta

    2006-01-01

    Background Superoxide mediated oxidative stress is a key neuropathologic mechanism in acute central nervous system injuries. We have analyzed the neuroprotective efficacy of the transient overexpression of antioxidant enzyme Cu/Zn Superoxide dismutase (SOD) after excitotoxic injury to the immature rat brain by using a recently constructed modular protein vector for non-viral gene delivery termed NLSCt. For this purpose, animals were injected with the NLSCt vector carrying the Cu/Zn SOD or the control GFP transgenes 2 hours after intracortical N-methyl-D-aspartate (NMDA) administration, and daily functional evaluation was performed. Moreover, 3 days after, lesion volume, neuronal degeneration and nitrotyrosine immunoreactivity were evaluated. Results Overexpression of Cu/Zn SOD transgene after NMDA administration showed improved functional outcome and a reduced lesion volume at 3 days post lesion. In secondary degenerative areas, increased neuronal survival as well as decreased numbers of degenerating neurons and nitrotyrosine immunoreactivity was seen. Interestingly, injection of the NLSCt vector carrying the control GFP transgene also displayed a significant neuroprotective effect but less pronounced. Conclusion When the appropriate levels of Cu/Zn SOD are expressed transiently after injury using the non-viral modular protein vector NLSCt a neuroprotective effect is seen. Thus recombinant modular protein vectors may be suitable for in vivo gene therapy, and Cu/Zn SOD should be considered as an interesting therapeutic transgene. PMID:16638118

  15. Neuroprotection from NMDA excitotoxic lesion by Cu/Zn superoxide dismutase gene delivery to the postnatal rat brain by a modular protein vector

    Directory of Open Access Journals (Sweden)

    Castellano Bernardo

    2006-04-01

    Full Text Available Abstract Background Superoxide mediated oxidative stress is a key neuropathologic mechanism in acute central nervous system injuries. We have analyzed the neuroprotective efficacy of the transient overexpression of antioxidant enzyme Cu/Zn Superoxide dismutase (SOD after excitotoxic injury to the immature rat brain by using a recently constructed modular protein vector for non-viral gene delivery termed NLSCt. For this purpose, animals were injected with the NLSCt vector carrying the Cu/Zn SOD or the control GFP transgenes 2 hours after intracortical N-methyl-D-aspartate (NMDA administration, and daily functional evaluation was performed. Moreover, 3 days after, lesion volume, neuronal degeneration and nitrotyrosine immunoreactivity were evaluated. Results Overexpression of Cu/Zn SOD transgene after NMDA administration showed improved functional outcome and a reduced lesion volume at 3 days post lesion. In secondary degenerative areas, increased neuronal survival as well as decreased numbers of degenerating neurons and nitrotyrosine immunoreactivity was seen. Interestingly, injection of the NLSCt vector carrying the control GFP transgene also displayed a significant neuroprotective effect but less pronounced. Conclusion When the appropriate levels of Cu/Zn SOD are expressed transiently after injury using the non-viral modular protein vector NLSCt a neuroprotective effect is seen. Thus recombinant modular protein vectors may be suitable for in vivo gene therapy, and Cu/Zn SOD should be considered as an interesting therapeutic transgene.

  16. Mitochondria-targeted superoxide dismutase (SOD2) regulates radiation resistance and radiation stress response in HeLa cells

    International Nuclear Information System (INIS)

    Hosoki, Ayaka; Yonekura, Shin-Ichiro; Zhao, Qing-Li

    2012-01-01

    Reactive oxygen species (ROS) act as a mediator of ionizing radiation-induced cellular damage. Previous studies have indicated that MnSOD (SOD2) plays a critical role in protection against ionizing radiation in mammalian cells. In this study, we constructed two types of stable HeLa cell lines overexpressing SOD2, HeLa S3/SOD2 and T-REx HeLa/SOD2, to elucidate the mechanisms underlying the protection against radiation by SOD2. SOD2 overexpression in mitochondria enhanced the survival of HeLa S3 and T-REx HeLa cells following γ-irradiation. The levels of γH2AX significantly decreased in HeLa S3/SOD2 and T-REx HeLa/SOD2 cells compared with those in the control cells. MitoSox TM Red assays showed that both lines of SOD2-expressing cells showed suppression of the superoxide generation in mitochondria. Furthermore, flow cytometry with a fluorescent probe (2',7'-dichlorofluorescein) revealed that the cellular levels of ROS increased in HeLa S3 cells during post-irradiation incubation, but the increase was markedly attenuated in HeLa S3/SOD2 cells. DNA microarray analysis revealed that, of 47,000 probe sets analyzed, 117 and 166 probes showed more than 2-fold changes after 5.5 Gy of γ-irradiation in control and HeLa S3/SOD2 cells, respectively. Pathway analysis revealed different expression profiles in irradiated control cells and irradiated SOD2-overexpressing cells. These results indicate that SOD2 protects HeLa cells against cellular effects of γ-rays through suppressing oxidative stress in irradiated cells caused by ROS generated in the mitochondria and through regulating the expression of genes which play a critical role in protection against ionizing radiation. (author)

  17. Lethal doses of ionizing radiation versus endogenous level of superoxide dismutase

    Energy Technology Data Exchange (ETDEWEB)

    Lipecka, K; Domanski, T; Dniaszewska, K; Grabowska, B; Pietrowicz, D; Lindner, P; Cisowska, B; Gorski, H [Military Medical Academy, Lodz (Poland). Inst. of Occupational Medicine

    1982-06-22

    The stability of superoxide dismutase (SOD) as well as its activity distribution in a human population were investigated. The SOD activity level of the erythrocytes proved to be an index for the endogenous SOD activity in the whole body. In a rat population, having similar SOD frequency distribution as a human population, the mortality due to acute irradiation depended on the SOD level; after a single acute dose approximating the lethal dose (LD/sub 50/30/) the survival depended distinctly on the endogenous SOD activity level.

  18. Zymography Methods to Simultaneously Analyze Superoxide Dismutase and Catalase Activities: Novel Application for Yeast Species Identification.

    Science.gov (United States)

    Gamero-Sandemetrio, Esther; Gómez-Pastor, Rocío; Matallana, Emilia

    2017-01-01

    We provide an optimized protocol for a double staining technique to analyze superoxide dismutase enzymatic isoforms Cu-Zn SOD (Sod1) and Mn-SOD (Sod2) and catalase in the same polyacrylamide gel. The use of NaCN, which specifically inhibits yeast Sod1 isoform, allows the analysis of Sod2 isoform while the use of H 2 O 2 allows the analysis of catalase. The identification of a different zymography profiling of SOD and catalase isoforms in different yeast species allowed us to propose this technique as a novel yeast identification and classification strategy.

  19. Studies on protective effects of superoxide dismutase on radiation induced-chromosomal aberrations

    International Nuclear Information System (INIS)

    Zheng Siying; Jiang Jiagui; Lin Xingcheng

    1987-09-01

    This study demonstrates that radiation induced-chromosomal aberrations are not only due to the direct effect of radiation h it , but the indirect effect of free radical as well. Therefore, chromosome damage induced by radiation may be reduced by adding exogenous SOD into the radiation exposed lymphocyte culture to eliminate the superoxide free radical which damages DNA. On the other hand, however, the radiosensitivity of lymphocytes can be raised by adding SOD inhibitor (DDC) into the lymphocyte culture, which makes radiation induced-chromosomal damages more severely

  20. Super-oxidation of silicon nanoclusters: magnetism and reactive oxygen species at the surface

    Energy Technology Data Exchange (ETDEWEB)

    Lepeshkin, Sergey; Baturin, Vladimir; Tikhonov, Evgeny; Matsko, Nikita; Uspenskii, Yurii; Naumova, Anastasia; Feya, Oleg; Schoonen, Martin A.; Oganov, Artem R.

    2016-01-01

    Oxidation of silicon nanoclusters depending on the temperature and oxygen pressure is explored from first principles using the evolutionary algorithm, and structural and thermodynamic analysis. From our calculations of 90 SinOm clusters we found that under normal conditions oxidation does not stop at the stoichiometric SiO2 composition, as it does in bulk silicon, but goes further placing extra oxygen atoms on the cluster surface. These extra atoms are responsible for light emission, relevant to reactive oxygen species and many of them are magnetic. We argue that the super-oxidation effect is size-independent and discuss its relevance to nanotechnology and miscellaneous applications, including biomedical ones.

  1. Experimental and numerical validation of the effective medium theory for the B-term band broadening in 1st and 2nd generation monolithic silica columns.

    Science.gov (United States)

    Deridder, Sander; Vanmessen, Alison; Nakanishi, Kazuki; Desmet, Gert; Cabooter, Deirdre

    2014-07-18

    Effective medium theory (EMT) expressions for the B-term band broadening in monolithic silica columns are presented at the whole-column as well as at the mesoporous skeleton level. Given the bi-continuous nature of the monolithic medium, regular as well as inverse formulations of the EMT-expressions have been established. The established expressions were validated by applying them to a set of experimental effective diffusion (Deff)-data obtained via peak parking on a number of 1st and 2nd generation monolithic silica columns, as well as to a set of numerical diffusion simulations in a simplified monolithic column representation (tetrahedral skeleton model) with different external porosities and internal diffusion coefficients. The numerically simulated diffusion data can be very closely represented over a very broad range of zone retention factors (up to k″=80) using the established EMT-expressions, especially when using the inverse variant. The expressions also allow representing the experimentally measured effective diffusion data very closely. The measured Deff/Dmol-values were found to decrease significantly with increasing retention factor, in general going from about Deff/Dmol=0.55 to 0.65 at low k″ (k″≅1.5-3.8) to Deff/Dmol=0.25 at very high k″ (k″≅40-80). These values are significantly larger than observed in fully-porous and core-shell particles. The intra-skeleton diffusion coefficient (Dpz) was typically found to be of the order of Dpz/Dmol=0.4, compared to Dpz/Dmol=0.2-0.35 observed in most particle-based columns. These higher Dpz/Dmol values are the cause of the higher Deff/Dmol values observed. In addition, it also appears that the higher internal diffusion is linked to the higher porosity of the mesoporous skeleton that has a relatively open structure with relatively wide pores. The observed (weak) relation between Dpz/Dmol and the zone retention factor appears to be in good agreement with that predicted when applying the regular

  2. Assessment of the long-term stability of cementitious barriers of radioactive waste repositories by using digital-image-based microstructure generation and reactive transport modelling

    International Nuclear Information System (INIS)

    Galindez, Juan Manuel; Molinero, Jorge

    2010-01-01

    Cement-based grout plays a significant role in the design and performance of nuclear waste repositories: used correctly, it can enhance their safety. However, the high water-to-binder ratios, which are required to meet the desired workability and injection ability at early age, lead to high porosity that may affect the durability of this material and undermine its long-term geochemical performance. In this paper, a new methodology is presented in order to help the process of mix design which best meets the compromise between these two conflicting requirements. It involves the combined use of the computer programs CEMHYD3D for the generation of digital-image-based microstructures and CrunchFlow, for the reactive transport calculations affecting the materials so simulated. This approach is exemplified with two grout types, namely, the so-called Standard mix 5/5, used in the upper parts of the structure, and the 'low-pH' P308B, to be injected at higher depths. The results of the digital reconstruction of the mineralogical composition of the hardened paste are entirely logical, as the microstructures display high degrees of hydration, large porosities and low or nil contents of aluminium compounds. Diffusion of solutes in the pore solution was considered to be the dominant transport process. A single scenario was studied for both mix designs and their performances were compared. The reactive transport model adequately reproduces the process of decalcification of the C-S-H and the precipitation of calcite, which is corroborated by empirical observations. It was found that the evolution of the deterioration process is sensitive to the chemical composition of groundwater, its effects being more severe when grout is set under continuous exposure to poorly mineralized groundwater. Results obtained appear to indicate that a correct conceptualization of the problem was accomplished and support the assumption that, in absence of more reliable empirical data, it might

  3. A PKM Generated by Calpain Cleavage of a Classical PKC Is Required for Activity-Dependent Intermediate-Term Facilitation in the Presynaptic Sensory Neuron of "Aplysia"

    Science.gov (United States)

    Farah, Carole A.; Hastings, Margaret H.; Dunn, Tyler W.; Gong, Katrina; Baker-Andresen, Danay; Sossin, Wayne S.

    2017-01-01

    Atypical PKM, a persistently active form of atypical PKC, is proposed to be a molecular memory trace, but there have been few examinations of the role of PKMs generated from other PKCs. We demonstrate that inhibitors used to inhibit PKMs generated from atypical PKCs are also effective inhibitors of other PKMs. In contrast, we demonstrate that…

  4. National Energy Plan 2030: a proposal for power generation expansion in the long term; Plano Nacional de Energia 2030: uma proposta de expansao para a geracao de energia eletrica no longo prazo

    Energy Technology Data Exchange (ETDEWEB)

    Guerreiro, Amilcar Goncalves; Pereira Junior, Amaro Olimpio; Lopes, Juarez Castrillon; Tavares, Marina Elisabete E.; Silva, Renata de A.M. da; Queiroz, Renato P.; Oliveira, Ricardo G. de [Empresa de Pesquisa Energetica (EPE), Brasilia, DF (Brazil)

    2008-07-01

    The article aims to present and discuss a proposal for electric energy expansion generation capacity in long term. This work identifies the most appropriate evolution of the hydrothermal mix for the expansion of the supply of electrical power in the country, over the horizon of planning by 2030. (author)

  5. Group Theory and Crystal Field Theory: A Simple and Rigorous Derivation of the Spectroscopic Terms Generated by the t[subscript 2g][superscript 2] Electronic Configuration in a Strong Octahedral Field

    Science.gov (United States)

    Morpurgo, Simone

    2007-01-01

    The principles of symmetry and group theory are applied to the zero-order wavefunctions associated with the strong-field t[subscript 2g][superscript 2] configuration and their symmetry-adapted linear combinations (SALC) associated with the generated energy terms are derived. This approach will enable students to better understand the use of…

  6. Aortic superoxide production at the early hyperglycemic stage in a rat type 2 diabetes model and the effects of pravastatin.

    Science.gov (United States)

    Kikuchi, Chigusa; Kajikuri, Junko; Hori, Eisei; Nagami, Chie; Matsunaga, Tamihide; Kimura, Kazunori; Itoh, Takeo

    2014-01-01

    Endothelium-derived superoxide induces vascular dysfunctions. The aim of this study was to examine the activity of protein kinase C (PKC) isoforms and endothelial nitric oxide synthase (eNOS), which leads to vascular superoxide production in type 2 diabetes, in addition to the effects of pravastatin. We studied these mechanisms in Otsuka Long-Evans Tokushima Fatty (OLETF) rats (type 2 diabetes model) at the early hyperglycemic stage (vs. non-diabetic Long-Evans Tokushima Otsuka [LETO] rats). Superoxide production and catalase activity were measured in aortas, as were the protein expressions of PKCδ and phospho-Ser(1177) eNOS. Superoxide production was increased in OLETF rats, and this increase was inhibited by the selective conventional PKC (cPKC) inhibitor Gö6976 and by the non-selective cPKC and novel PKC inhibitor GF109203X. Phospho-Ser(1177) eNOS was significantly increased in OLETF rats, whereas the protein expressions of PKCδ and phosopho-Thr(505) PKCδ and catalase activity were all greatly reduced. Pravastatin administration to OLETF rats in vivo had normalizing effects on all of these variables. The increment in superoxide production seen in OLETF rats (but not the production in pravastatin-treated OLETF rats) was abolished by high concentration of N(ω)-nitro-L-arginine methyl ester (electron transport inhibitor of eNOS), by sepiapterin (precursor of tetrahydrobiopterin), and by LY294002 (phosphatidylinositol 3-kinase [PI3-kinase] inhibitor). In OLETF rats at the early hyperglycemic stage, aortic superoxide production is increased owing to activation of uncoupled eNOS through phosphorylation by PI3-kinase/Akt. This may be related to the observed reduction in PKCδ/catalase activities. Pravastatin inhibited endothelial superoxide production via normalization of PKCδ/catalase activities.

  7. Targeting superoxide dismutase to endothelial caveolae profoundly alleviates inflammation caused by endotoxin.

    Science.gov (United States)

    Shuvaev, Vladimir V; Kiseleva, Raisa Yu; Arguiri, Evguenia; Villa, Carlos H; Muro, Silvia; Christofidou-Solomidou, Melpo; Stan, Radu V; Muzykantov, Vladimir R

    2018-02-28

    Inflammatory mediators binding to Toll-Like receptors (TLR) induce an influx of superoxide anion in the ensuing endosomes. In endothelial cells, endosomal surplus of superoxide causes pro-inflammatory activation and TLR4 agonists act preferentially via caveolae-derived endosomes. To test the hypothesis that SOD delivery to caveolae may specifically inhibit this pathological pathway, we conjugated SOD with antibodies (Ab/SOD, size ~10nm) to plasmalemmal vesicle-associated protein (Plvap) that is specifically localized to endothelial caveolae in vivo and compared its effects to non-caveolar target CD31/PECAM-1. Plvap Ab/SOD bound to endothelial cells in culture with much lower efficacy than CD31 Ab/SOD, yet blocked the effects of LPS signaling with higher efficiency than CD31 Ab/SOD. Disruption of cholesterol-rich membrane domains by filipin inhibits Plvap Ab/SOD endocytosis and LPS signaling, implicating the caveolae-dependent pathway(s) in both processes. Both Ab/SOD conjugates targeted to Plvap and CD31 accumulated in the lungs after IV injection in mice, but the former more profoundly inhibited LPS-induced pulmonary inflammation and elevation of plasma level of interferon-beta and -gamma and interleukin-27. Taken together, these results indicate that targeted delivery of SOD to specific cellular compartments may offer effective, mechanistically precise interception of pro-inflammatory signaling mediated by reactive oxygen species. Copyright © 2018 Elsevier B.V. All rights reserved.

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

    International Nuclear Information System (INIS)

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

    1986-01-01

    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 - ) for murine Cu-Zn-SOD was determined to be 6.8 x 10 -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

  9. Effect of Juglone foliar injection on Superoxide dismutases antioxidant system in two Musa spp cultivars

    Directory of Open Access Journals (Sweden)

    Michel Leiva Mora

    2004-04-01

    Full Text Available Some diseases in higher plants cause formation of reactive oxygen species (ROS which acts like mediator on tolerance to oxidative stress. Several phytotoxins produced by plant pathogen fungus induce ROS by different mechanisms which damage plant cell tissues. This paper was focused to determine juglone impact (Psedocercospora fijiensis toxin on Superoxide dismutases antioxidant system in Fougamou (ABB and Grande naine (AAA by native Poliacrylamide gel electrophoresis (PAGE 10%. Samples of proteins were collected at 2, 4, 6, 8 and 48h after juglone injection on both Musa cultivar and 65 μl of them (120 μg of total protein were applied to gels. Gels were incubated in staining solution (25 mg.ml-1 de Nitrobluetetrazolium (NTB and 0.1 mg.ml-1 de riboflavin and were exposured to fluorescent light. In both cultivars it was observed changes in expression patterns of superoxide dismutases between injected and not injected plants. On Grande naine (AAA 4 h after injection an isoform of SOD disappeared respect to control. Nevertheless on Fougamou (ABB, 2 h after injection it was activated a new isoform which was observed until 48 h. In the present work it was observed a correspondence between protein patterns expression of SOD isoforms and tolerance to oxidative stress caused by the effect of juglone on Musa spp. Key words: antioxidant enzymes, Mycosphaerella fijiensis,oxidative stress, toxins

  10. Superoxide Dismutase as a Tool for the Mulacular Identification of Plant Parasitic Nematodes

    Directory of Open Access Journals (Sweden)

    S. Molinari

    2004-08-01

    Full Text Available Superoxide dismutase (SOD is a constitutive family of enzymes produced by all aerobic organisms. Varying amounts of SOD activity have been found at all life stages of the most diffused plant parasitic nematodes. SOD is important to aerobic metabolism and parasitism of nematodes in that it catalyzes the first step of the neutralization of the highly toxic superoxide anion (O2 •-, which is largely produced in plant-nematode incompatible reactions. SOD has also been shown to be a significant tool to diagnose root-knot, cyst-, and longidorid nematodes. A high SOD polymorphism has been revealed by Native-Page on gradient polyacrylamide gels for Meloidogyne spp. and by isoelectrofocusing for Globodera, Xiphinema and Longidorus spp. The sensitivity of such procedures has been improved by using the PhastSystem (Amersham Biosciences, Piscata, NJ, USA, an automated equipment for electrophoresis. An accurate discrimination of species of all the nematode genera tested has been achieved and an attempt was made to group populations of the Xiphinema americanum-group and to detect Globodera rostochiensis and G. pallida pathotypes.

  11. Oxygen-dependent radiosensitivity of Escherichia coli and mitigation in lethality by superoxide dismutase

    International Nuclear Information System (INIS)

    Niwa, Taeko; Yamaguchi, Hikoyuki; Yano, Keiji

    1978-01-01

    Oxygen-dependent radiosensitivity of Escherichia coli W3623 his - was confirmed. Regarding cellular superoxide dismutase (SOD), cells grown oxically gained higher activity than those anoxically, however, the reinforced enzyme level could not compensate the oxygen effect, i.e., the enhanced lethal effect of oxic γ-irradiation. Rather, the enhancement of oxygen effect was found in cells grown oxically compared with those anoxically. Oxygen enhanced lethality was mitigated to the extent by the amount of added SOD into the cell suspension to be irradiated. The results supported a proposal that superoxide anion, O 2 - , is involved in the oxygen effect, with the most likely site of the damage in the outer structure of cell but not in the cell matrix. Reverse oxygen effect could be found with lambda phage DNA in transfecting ability. Added SOD protected phage DNA somewhat in oxic irradiation. While considerable protections were found in anoxic one with the added SOD even autoclaved but their function was still unknown. (auth.)

  12. Inhibition of oxygen-dependent radiation-induced damage by the nitroxide superoxide dismutase mimic, tempol

    International Nuclear Information System (INIS)

    Mitchell, J.B.; DeGraff, W.; Kaufman, D.; Krishna, M.C.; Samuni, A.; Finkelstein, E.; Ahn, M.S.; Hahn, S.M.; Gamson, J.; Russo, A.

    1991-01-01

    Stable nitroxide radicals have been previously shown to function as superoxide dismutase (SOD)2 mimics and to protect mammalian cells against superoxide and hydrogen peroxide-mediated oxidative stress. These unique characteristics suggested that nitroxides, such as 4-hydroxy-2,2,6,6-tetramethylpiperidine-1-oxyl (Tempol), might protect mammalian cells against ionizing radiation. Treating Chinese hamster cells under aerobic conditions with 5, 10, 50, and 100 mM Tempol 10 min prior to X-rays resulted in radiation protection factors of 1.25, 1.30, 2.1, and 2.5, respectively. However, the reduced form of Tempol afforded no protection. Tempol treatment under hypoxic conditions did not provide radioprotection. Aerobic X-ray protection by Tempol could not be attributed to the induction of intracellular hypoxia, increase in intracellular glutathione, or induction of intracellular SOD mRNA. Tempol thus represents a new class of non-thiol-containing radiation protectors, which may be useful in elucidating the mechanism(s) of radiation-induced cellular damage and may have broad applications in protecting against oxidative stress

  13. The Cu,Zn Superoxide Dismutase: not only a dismutase enzyme

    Directory of Open Access Journals (Sweden)

    Paolo Mondola

    2016-11-01

    Full Text Available The Cu,Zn superoxide dismutase (SOD1 is an ubiquitary cytosolic dimeric carbohydrate free molecule, belonging to a family of isoenzymes involved in the scavenger of superoxide anions. This effect certainly represents the main and well known function ascribed to this enzyme. Here we highlight new aspects of SOD1 physiology that point out some inedited effects of this enzyme in addition to the canonic role of oxygen radical enzymatic dismutation. In the last two decades our research group produced many data obtained in in vitro studies performed in many cellular lines, mainly neuroblastoma SK-N-BE cells, indicating that this enzyme is secreted either constitutively or after depolarization induced by high extracellular K+ concentration. In addition, we gave many experimental evidences showing that SOD1 is able to stimulate, through muscarinic M1 receptor, pathways involving ERK1/2 and AKT activation. These effects are accompanied with an intracellular calcium increase. In the last part of this review we describe researches that link deficient extracellular secretion of mutant SOD1G93A to its intracellular accumulation and toxicity in NSC-34 cells. Alternatively, SOD1G93A toxicity has been attributed to a decrease of Km for H2O2 with consequent OH. radical formation. Interestingly, this last inedited effect of SOD1G93A could represent a gain of function that could be involved in the pathogenesis of familial Amyotrophic Lateral Sclerosis (fALS.

  14. Paroxysmal atrial fibrillation: dynamics of the main antioxidant enzymes--superoxide dismutase and catalase.

    Science.gov (United States)

    Negreva, Mariya N; Penev, Atanas P; Georgiev, Svetoslav Zh; Aleksandrova, Albena A

    2014-01-01

    Researchers have a particularly strong interest in the mechanisms implicated in the clinical manifestation of atrial fibrillation. To examine dynamically the activity of the antioxidant enzymes, superoxide dismutase and catalase in patients with paroxysmal atrial fibrillation (duration enzyme activity was determined by a spectrophotometric method. The average duration of atrial fibrillation episodes until the time of hospitalization was 8.14 hours (from 2 to 24 hours). During patient hospitalization the activity of superoxide dismutase and catalase was considerably higher compared to that of the controls (8.46 +/- 0.26 vs 5.81 +/- 0.14 U/mg Hb; 7.36 +/- 0.25 vs 4.76 +/- 0.12 E240/min/mg Hb; P catalase remained increased (5.11 +/- 0.08 vs 4.76 +/- 0.12 E240/min/mg Hb, p catalase even in the early hours of clinical manifestation of the disorder, which then slowly decreased with the restoration of sinus rhythm. Therefore, we can conclude that changes in oxidative status are closely related to the disease and are probably a part of the intimate mechanisms related to its initiation and clinical course.

  15. Effect of intradermal human recombinant copper-zinc superoxide dismutase on random pattern flaps in rats.

    Science.gov (United States)

    Schein, Ophir; Westreich, Melvyn; Shalom, Avshalom

    2013-09-01

    Studies have focused on enhancing flap viability using superoxide dismutase (SOD), but only a few used SOD from human origin, and most gave the compound systemically. We evaluated the ability of SOD to improve random skin flap survival using human recombinant copper-zinc superoxide dismutase (Hr-CuZnSOD) in variable doses, injected intradermally into the flap. Seventy male Sprague Dawley rats were randomly assigned into 4 groups. Cephalic random pattern flaps were elevated on their backs and intradermal injections of different dosages of Hr-CuZnSOD were given 15 minutes before surgery. Flap survival was evaluated by fluorescein fluorescence. Analysis of variance (ANOVA) and t test statistical analyses were performed. Flap survival in all treated groups was significantly better than in the controls. The beneficial effect of HR-CuZnSOD on flap survival is attained when it is given intradermally into the flap tissue. Theoretically, Hr-CuZnSOD delivered with local anesthetics used in flap elevation may be a valuable clinical tool. Copyright © 2012 Wiley Periodicals, Inc.

  16. A pulse-radiolysis study of the manganese-containing superoxide dismutase from Bacillus stearothermophilus

    International Nuclear Information System (INIS)

    McAdam, M.E.; Fox, R.A.; Lavelle, F.; Fielden, E.M.

    1977-01-01

    The enzymic reaction mechanism of a manganese-containing superoxide dismutase from Bacillus stearothermophilus was studied by using pulse radiolysis. During catalysis (pH 8.9; 25 0 C), changes occurring in the kinetics of substrate disappearance and in the visible absorption of the enzyme at 480 nm established that the simple two-step mechanism found for copper- and iron-containing superoxide dismutases was not involved. At a low ratio ( 2 sup(-.) was close to exponential, whereas at much higher ratios (> 100) the observed decay was predominantly zero-order. The simplest interpretation of the results invokes a rapid one-electron oxidation-reduction cycle ('the fast cycle') and, concurrently, a slower reaction giving a form of the enzyme that is essentially unreactive towards O 2 sup(-.) but which undergoes a first-order decay to yield fully active native enzyme ('the slow cycle'). The fast cycle involved the native enzyme Esub(A) and a form of the enzyme Esub(B) which could be obtained also be treating the form Esub(A) with H 2 O 2 . Computer calculations made with such a simple model predicted behaviour in excellent agreement with the observed results. (author)

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

    Science.gov (United States)

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

    2012-10-04

    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.

  18. Glossary of Terms. Preservation of Records, Knowledge and Memory (RK and M) Across Generations. Draft - Definitions as of 3 March 2014

    International Nuclear Information System (INIS)

    2014-01-01

    The RK and M glossary defines important concepts and terms that are commonly used. It is under continuous development by the project team and represents a peer-reviewed set of terms. It should be pointed out that some terms may be defined differently from other glossaries in science and technology. The RK and M glossary, however, fits the purpose of achieving a better understanding and more efficient communication of RK and M issues. The aim of the RK and M glossary is to compile a dedicated, internally consistent, and unambiguous set of definitions. Each definition should not be seen in isolation, but as complementary to the definition of other terms in the glossary

  19. Enhanced reactive oxygen species scavenging by overproduction of superoxide dismutase and catalase delays postharvest physiological deterioration of cassava storage roots.

    Science.gov (United States)

    Xu, Jia; Duan, Xiaoguang; Yang, Jun; Beeching, John R; Zhang, Peng

    2013-03-01

    Postharvest physiological deterioration (PPD) of cassava (Manihot esculenta) storage roots is the result of a rapid oxidative burst, which leads to discoloration of the vascular tissues due to the oxidation of phenolic compounds. In this study, coexpression of the reactive oxygen species (ROS)-scavenging enzymes copper/zinc superoxide dismutase (MeCu/ZnSOD) and catalase (MeCAT1) in transgenic cassava was used to explore the intrinsic relationship between ROS scavenging and PPD occurrence. Transgenic cassava plants integrated with the expression cassette p54::MeCu/ZnSOD-35S::MeCAT1 were confirmed by Southern-blot analysis. The expression of MeCu/ZnSOD and MeCAT1 was verified by quantitative reverse transcription-polymerase chain reaction and enzymatic activity analysis both in the leaves and storage roots. Under exposure to the ROS-generating reagent methyl viologen or to hydrogen peroxide (H2O2), the transgenic plants showed higher enzymatic activities of SOD and CAT than the wild-type plants. Levels of malondialdehyde, chlorophyll degradation, lipid peroxidation, and H2O2 accumulation were dramatically reduced in the transgenic lines compared with the wild type. After harvest, the storage roots of transgenic cassava lines show a delay in their PPD response of at least 10 d, accompanied by less mitochondrial oxidation and H2O2 accumulation, compared with those of the wild type. We hypothesize that this is due to the combined ectopic expression of Cu/ZnSOD and CAT leading to an improved synergistic ROS-scavenging capacity of the roots. Our study not only sheds light on the mechanism of the PPD process but also develops an effective approach for delaying the occurrence of PPD in cassava.

  20. Amelioration of radiation induced decrease in activity of catalase and superoxide dismutase in mouse liver by Punica granatum

    International Nuclear Information System (INIS)

    Sharma, Jaimala; Mathur, Aarti

    2013-01-01

    Ionizing radiation generates reactive oxygen species (ROS) in irradiated tissue. Cells of liver have their own defence system, the antioxidant system to deactivate ROS. Antioxidant system includes enzymatic and non-enzymatic components. Liver is rich in endogenous antioxidants and related enzymes. Catalase and Superoxide dismutase (SOD) are powerful antioxidant enzymes. In the present study Punica granatum fruit rind Ethanol extract (PGFRE) was tested against 60 Co gamma radiation induced alteration in Swiss albino mouse. Healthy adult (25±2) Swiss albino mouse were selected and divided into four groups. The first group was sham irradiated. The second group was irradiated with 8 Gy 60 Co gamma radiation only and served as control. The third group was administered with Ethanol extract of Punica granatum fruit rind one hour before irradiation at the dose rate of 10 mg/kg body weight orally. Animals were exposed to 8 Gy 60 Co gamma radiation. Fourth group was administered with Ethanol extract of Punica granatum fruit rind at the dose rate of 10 mg/kg body weight. Mice were sacrificed at various post irradiation intervals and liver was removed, weighed and analysed biochemically for Catalase and SOD activity. Catalase and SOD activity decreased up till 7th post irradiation day in 8 Gy irradiated group than normal. In PGFRE pretreated irradiated group catalase and SOD activity were higher than the corresponding control group at all the intervals. These results indicate that PGFRE extract protects damage to the catalase and SOD activity in liver of Swiss albino mouse against lethal dose of gamma radiation. (author)

  1. Disulfide scrambling in superoxide dismutase 1 reduces its cytotoxic effect in cultured cells and promotes protein aggregation.

    Directory of Open Access Journals (Sweden)

    Lina Leinartaitė

    Full Text Available Mutations in the gene coding for superoxide dismutase 1 (SOD1 are associated with familiar forms of the neurodegenerative disease amyotrophic lateral sclerosis (ALS. These mutations are believed to result in a "gain of toxic function", leading to neuronal degeneration. The exact mechanism is still unknown, but misfolding/aggregation events are generally acknowledged as important pathological events in this process. Recently, we observed that demetallated apoSOD1, with cysteine 6 and 111 substituted for alanine, is toxic to cultured neuroblastoma cells. This toxicity depended on an intact, high affinity Zn(2+ site. It was therefor contradictory to discover that wild-type apoSOD1 was not toxic, despite of its high affinity for Zn(2+. This inconsistency was hypothesized to originate from erroneous disulfide formation involving C6 and C111. Using high resolution non-reducing SDS-PAGE, we have in this study demonstrated that the inability of wild-type apoSOD1 to cause cell death stems from formation of non-native intra-molecular disulfides. Moreover, monomeric apoSOD1 variants capable of such disulfide scrambling aggregated into ThT positive oligomers under physiological conditions without agitation. The oligomers were stabilized by inter-molecular disulfides and morphologically resembled what has in other neurodegenerative diseases been termed protofibrils. Disulfide scrambling thus appears to be an important event for misfolding and aggregation of SOD1, but may also be significant for protein function involving cysteines, e.g. mitochondrial import and copper loading.

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

    Directory of Open Access Journals (Sweden)

    Milene Valéria Lopes

    2012-01-01

    Full Text Available 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.

  3. Transient structural distortion of metal-free Cu/Zn superoxide dismutase triggers aberrant oligomerization

    DEFF Research Database (Denmark)

    Teilum, Kaare; Smith, Melanie H; Schulz, Eike

    2009-01-01

    remained enigmatic, however, as is the case in other protein-misfolding diseases. Here, we target the critical conformational change that defines the earliest step toward aggregation. Using nuclear spin relaxation dispersion experiments, we identified a short-lived (0.4 ms) and weakly populated (0.......7%) conformation of metal-depleted SOD1 that triggers aberrant oligomerization. This excited state emanates from the folded ground state and is suppressed by metal binding, but is present in both the disulfide-oxidized and disulfide-reduced forms of the protein. Our results pinpoint a perturbed region......Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease linked to the misfolding of Cu/Zn superoxide dismutase (SOD1). ALS-related defects in SOD1 result in a gain of toxic function that coincides with aberrant oligomerization. The structural events triggering oligomerization have...

  4. Novel inhibitors to Taenia solium Cu/Zn superoxide dismutase identified by virtual screening

    Science.gov (United States)

    García-Gutiérrez, P.; Landa-Piedra, A.; Rodríguez-Romero, A.; Parra-Unda, R.; Rojo-Domínguez, A.

    2011-12-01

    We describe in this work a successful virtual screening and experimental testing aimed to the identification of novel inhibitors of superoxide dismutase of the worm Taenia solium ( TsCu/Zn-SOD), a human parasite. Conformers from LeadQuest® database of drug-like compounds were selected and then docked on the surface of TsCu/Zn-SOD. Results were screened looking for ligand contacts with receptor side-chains not conserved in the human homologue, with a subsequent development of a score optimization by a set of energy minimization steps, aimed to identify lead compounds for in vitro experiments. Six out of fifty experimentally tested compounds showed μM inhibitory activity toward TsCu/Zn-SOD. Two of them showed species selectivity since did not inhibit the homologous human enzyme when assayed in vitro.

  5. Microencapsulation of superoxide dismutase into poly(epsilon-caprolactone) microparticles by reverse micelle solvent evaporation.

    Science.gov (United States)

    Youan, Bi-Botti Célestin

    2003-01-01

    The aim of this work was to encapsulate superoxide dismutase (SOD) in poly(epsilon-caprolactone) (PCL) microparticles by reverse micelle solvent evaporation. The concentration of PCL, the hydrophile-lipophile balance (HLB), and concentration of the sucrose ester used as surfactant in the organic phase were investigated as formulation variables. Relatively higher encapsulation efficiency (approximately 48%) and retained enzymatic activity (>90%) were obtained with microparticle formulation made from the 20% (w/v) PCL and 0.05% (w/v) sucrose ester of HLB = 6. This formulation allowed the in vitro release of SOD for at least 72 hr. These results showed that reverse micelle solvent evaporation can be used to efficiently encapsulate SOD in PCL microparticles. Such formulations may improve the bioavailability of SOD.

  6. Angiotensin II stimulates superoxide production by nitric oxide synthase in thick ascending limbs.

    Science.gov (United States)

    Gonzalez-Vicente, Agustin; Saikumar, Jagannath H; Massey, Katherine J; Hong, Nancy J; Dominici, Fernando P; Carretero, Oscar A; Garvin, Jeffrey L

    2016-02-01

    Angiotensin II (Ang II) causes nitric oxide synthase (NOS) to become a source of superoxide (O2 (-)) via a protein kinase C (PKC)-dependent process in endothelial cells. Ang II stimulates both NO and O2 (-) production in thick ascending limbs. We hypothesized that Ang II causes O2 (-) production by NOS in thick ascending limbs via a PKC-dependent mechanism. NO production was measured in isolated rat thick ascending limbs using DAF-FM, whereas O2 (-) was measured in thick ascending limb suspensions using the lucigenin assay. Consistent stimulation of NO was observed with 1 nmol/L Ang II (P thick ascending limbs via a PKC- and NADPH oxidase-dependent process; and (2) the effect of Ang II is not due to limited substrate. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

  7. Serum and Ascitic Fluid Superoxide Dismutase and Malondialdehyde Levels in Patients with Cirrhosis

    Directory of Open Access Journals (Sweden)

    Ugur Coskun

    2008-01-01

    Full Text Available Serum and ascitic fluid superoxide dismutase (SOD and malondialdehyde (MDA levels were measured in 43 patients with cirrhosis and in a 10 healthy control group. Compensated cirrhotic patients had no clinically detectable ascites, but decompensated patients had massive ascites. Cirrhotic patients were divided into three groups: patients with compensated cirrhosis (n = 16, patients with decompensated cirrhosis with Spontaneous bacterial peritonitis (SBP (n = 14, and patients with decompensated cirrhosis without SBP (n = 13. All cirrhotic patients in the experimental group had significantly higher serum SOD (p 0.05. These results suggest that the increase in serum SOD and MDA levels are not related to the presence of SBP and the status of liver cirrhosis. To sum up, clarifying the impact of increased serum SOD and MDA levels in cirrhotic patients needs further investigation.

  8. Superoxide dismutase 1 is positively selected to minimize protein aggregation in great apes

    DEFF Research Database (Denmark)

    Dasmeh, Pouria; Kepp, Kasper Planeta

    2017-01-01

    Positive (adaptive) selection has recently been implied in human superoxide dismutase 1 (SOD1), a highly abundant antioxidant protein with energy signaling and antiaging functions, one of very few examples of direct selection on a human protein product (exon); the molecular drivers...... and SOD1 aggregates and triggered by aging. Our study thus marks an example of direct selection for a particular chemical phenotype (high net charge and stability) in a single human protein with possible implications for the evolution of aging....... of this selection are unknown. We mapped 30 extant SOD1 sequences to the recently established mammalian species tree and inferred ancestors, key substitutions, and signatures of selection during the protein's evolution. We detected elevated substitution rates leading to great apes (Hominidae) at ~1 per 2 million...

  9. Cloning and expression of an iron-containing superoxide dismutase in the parasitic protist, Trichomonas vaginalis.

    Science.gov (United States)

    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.

  10. Progress in Understanding Algal Bloom-Mediated Fish Kills: The Role of Superoxide Radicals, Phycotoxins and Fatty Acids.

    Directory of Open Access Journals (Sweden)

    Juan José Dorantes-Aranda

    Full Text Available 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

  11. Safety evaluation report related to the full-term operating license for San Onofre Nuclear Generating Station, Unit 1 (Docket No. 50-206)

    International Nuclear Information System (INIS)

    1991-07-01

    The safety evaluation report for the full-term operating license application filed by the Southern California Edison Company and the San Diego Gas and Electric Company has been prepared by the Office of Nuclear Reactor Regulation of the US Nuclear Regulatory Commission. The facility is located in San Diego County, California. The staff has evaluated the issues related to the conversion of the provisional operating license to a full-term operating license and concluded that the facility can continue to be operated without endangering the health and safety of the public following the license conversion. 43 refs., 3 figs., 3 tabs

  12. Antioxidant therapy attenuates myocardial telomerase activity reduction in superoxide dismutase-deficient mice.

    Science.gov (United States)

    Makino, Naoki; Maeda, Toyoki; Oyama, Jun-ichi; Sasaki, Makoto; Higuchi, Yoshihiro; Mimori, Koji; Shimizu, Takahiko

    2011-04-01

    Oxidative stress plays a pathological role in the development of heart failure. This study examined telomere biology in heart/muscle-specific manganese superoxide dismutase-deficient mice (H/M-SOD2(-/-)), which develop progressive congestive heart failure and exhibit pathology typical of dilated cardiomyopathy. EUK-8 (25mg/kg/day), a superoxide dismutase and catalase mimetic, was administered to H/M-SOD2(-/-) mice for four weeks beginning at 8 weeks of age. Telomere length, telomerase activity, telomere-associated proteins, and cell death signals were assessed in hearts from control wild-type mice (H/M-Sod2 (lox/ lox)) and H/M-SOD2(-/-) mice either treated or untreated with EUK-8. While cardiac function was unchanged in these experimental mice, the end-diastolic dimension in H/M-SOD2(-/-) mice was notably dilated and could be significantly reduced by EUK-8 treatment. At the end of the study, no shortening of telomere length was observed in heart tissues from all mice tested, but telomerase activity was decreased in heart tissue from H/M-SOD2(-/-) mice compared to control mice. Protein expression for telomerase reverse transcriptase and telomere repeat binding factor 2 was also downregulated in H/M-SOD2(-/-) heart tissue as was expression of phospho-Akt, insulin-like growth factor, and endothelial nitric oxide synthase. Expression levels of Sirt1, a lifespan modulator, were enhanced while FoxO3a was depressed in H/M-SOD2(-/-) hearts. All of the changes seen in H/M-SOD2(-/-) heart tissue could be inhibited by EUK-8 treatment. Taken together, the results suggest that oxidant stress might affect myocardial telomerase activity and telomere-associated proteins. Telomerase may therefore play a pivotal role in antioxidant defense mechanisms, and may be useful as a novel therapeutic tool for treating human heart failure. Copyright © 2010 Elsevier Ltd. All rights reserved.

  13. Quantification of superoxide radical production in thylakoid membrane using cyclic hydroxylamines.

    Science.gov (United States)

    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. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Antibacterial activity and safety of commercial veterinary cationic steroid antibiotics and neutral superoxidized water.

    Directory of Open Access Journals (Sweden)

    Benjamin E Bergstrom

    Full Text Available Antibiotic resistance of bacteria common to the ocular surface is an evolving problem. Thus, novel treatment options with new modes of action are required. We investigated the antibacterial activity and safety of three commercially available topical veterinary ophthalmic products (cationic steroid antibiotics, products A and B, and a neutral superoxidized water, product C to determine their potential use as antimicrobial alternatives. The minimum inhibitory concentrations (MIC of the three products were determined against 17 antibiotic resistant bacterial clinical isolates from the ocular surface. Using a standard cytotoxicity assay, the products at varying concentrations were evaluated with a corneal fibroblast cell line and a macrophage-like cell line to determine their potential toxic effect in vitro. The commercial ophthalmic solutions, ofloxacin 0.3%, tobramycin 0.3% and gentamicin 0.3% were used as positive controls for the MIC and tobramycin 0.3% was used as positive control for the cytotoxicity assays. For the MIC, Product C showed no inhibition of growth for any organisms, while Products A and B showed inhibition of growth similar to slightly less than the positive controls. For the cytotoxicity assays, Product C exhibited minimal toxicity while Products A and B exhibited toxicity similar to the controls. In conclusion, Product C had no antibacterial activity in these assays, while Products A and B had antibacterial profiles similar to slightly less than common topical ophthalmic antibiotics and cytotoxicity profiles similar to common topical ophthalmic antibiotics. To our knowledge, this is the first report on the antibacterial activity and safety of the cationic steroid antibiotics and superoxidized water.

  15. Perylene Diimide as a Precise Graphene-like Superoxide Dismutase Mimetic

    Energy Technology Data Exchange (ETDEWEB)

    Jalilov, Almaz S.; Nilewski, Lizanne G.; Berka, Vladimir [Hematology,; Zhang, Chenhao; Yakovenko, Andrey A. [Argonne National Laboratory, X-ray Science Division,; Wu, Gang [Hematology,; Kent, Thomas A. [Department; Center for Translational Research in Inflammatory Diseases, Michel E. DeBakey VA Medical Center, Houston, Texas 77030, United States; Tsai, Ah-Lim [Hematology,; Tour, James M.

    2017-01-31

    Here we show that the active portion of a graphitic nanoparticle can be mimicked by a perylene diimide (PDI) to explain the otherwise elusive biological and electrocatalytic activity of the nanoparticle construct. Development of molecular analogues that mimic the antioxidant properties of oxidized graphenes, in this case the poly(ethylene glycolated) hydrophilic carbon clusters (PEG–HCCs), will afford important insights into the highly efficient activity of PEG–HCCs and their graphitic analogues. PEGylated perylene diimides (PEGn–PDI) serve as well-defined molecular analogues of PEG–HCCs and oxidized graphenes in general, and their antioxidant and superoxide dismutase-like (SOD-like) properties were studied. PEGn–PDIs have two reversible reduction peaks, which are more positive than the oxidation peak of superoxide (O2•–). This is similar to the reduction peak of the HCCs. Thus, as with PEG–HCCs, PEGn–PDIs are also strong single-electron oxidants of O2•–. Furthermore, reduced PEGn–PDI, PEGn–PDI•–, in the presence of protons, was shown to reduce O2•– to H2O2 to complete the catalytic cycle in this SOD analogue. The kinetics of the conversion of O2•– to O2 and H2O2 by PEG8–PDI was measured using freeze-trap EPR experiments to provide a turnover number of 133 s–1; the similarity in kinetics further supports that PEG8–PDI is a true SOD mimetic. Finally, PDIs can be used as catalysts in the electrochemical oxygen reduction reaction in water, which proceeds by a two-electron process with the production of H2O2, mimicking graphene oxide nanoparticles that are otherwise difficult to study spectroscopically.

  16. The role of a cytosolic superoxide dismutase in barley-pathogen interactions

    KAUST Repository

    Lightfoot, Damien

    2016-03-19

    Reactive oxygen species (ROS), including superoxide (O2-HO2) and hydrogen peroxide (H2O2), are differentially produced during resistance responses to biotrophic pathogens and during susceptible responses to necrotrophic and hemi-biotrophic pathogens. Superoxide dismutase (SOD) is responsible for the catalysis of the dismutation of O2-HO2 to H2O2, regulating the redox status of plant cells. Increased SOD activity has been correlated previously with resistance in barley to the hemi-biotrophic pathogen Pyrenophora teres f. teres (Ptt, the causal agent of the net form of net blotch disease), but the role of individual isoforms of SOD has not been studied. A cytosolic CuZnSOD, HvCSD1, was isolated from barley and characterized as being expressed in tissue from different developmental stages. HvCSD1 was up-regulated during the interaction with Ptt and to a greater extent during the resistance response. Net blotch disease symptoms and fungal growth were not as pronounced in transgenic HvCSD1 knockdown lines in a susceptible background (cv. Golden Promise), when compared with wild-type plants, suggesting that cytosolic O2-HO2 contributes to the signalling required to induce a defence response to Ptt. There was no effect of HvCSD1 knockdown on infection by the hemi-biotrophic rice blast pathogen Magnaporthe oryzae or the biotrophic powdery mildew pathogen Blumeria graminis f. sp. hordei, but HvCSD1 also played a role in the regulation of lesion development by methyl viologen. Together, these results suggest that HvCSD1 could be important in the maintenance of the cytosolic redox status and in the differential regulation of responses to pathogens with different lifestyles.

  17. Short-Term Study Tours as a Driver for Increasing Domestic Student Mobility in Order to Generate Global Work-Ready Students and Cultural Exchange in Asia Pacific

    Science.gov (United States)

    Scharoun, Lisa

    2016-01-01

    Recent federal government programmes in Australia have seen a shift in focus from the international student towards increasing the possibilities for domestic mobility through short- and long-term exchange opportunities. The current New Colombo Plan funding scheme encourages Australian students, who have traditionally undertaken semester-long…

  18. Transcending Library Catalogs: A Comparative Study of Controlled Terms in Library of Congress Subject Headings and User-Generated Tags in LibraryThing for Transgender Books

    Science.gov (United States)

    Adler, Melissa

    2009-01-01

    Perhaps the greatest power of folksonomies, especially when set against controlled vocabularies like the Library of Congress Subject Headings, lies in their capacity to empower user communities to name their own resources in their own terms. This article analyzes the potential and limitations of both folksonomies and controlled vocabularies for…

  19. Skewing of X-chromosome inactivation in three generations of carriers with X-linked chronic granulomatous disease within one family

    NARCIS (Netherlands)

    Köker, M. Y.; Sanal, O.; de Boer, M.; Tezcan, I.; Metin, A.; Tan, C.; Ersoy, F.; Roos, D.

    2006-01-01

    BACKGROUND: Chronic granulomatous disease (CGD) is an inherited disorder of the innate immune system characterized by impairment of intracellular microbicidal activity of phagocytes. Mutations in one of the four known NADPH-oxidase components preclude generation of superoxide and related

  20. Long-term stable stacked CsPbBr3 quantum dot films for highly efficient white light generation in LEDs.

    Science.gov (United States)

    Song, Young Hyun; Yoo, Jin Sun; Kang, Bong Kyun; Choi, Seung Hee; Ji, Eun Kyung; Jung, Hyun Suk; Yoon, Dae Ho

    2016-12-01

    We report highly efficient ethyl cellulose with CsPbBr 3 perovskite QD films for white light generation in LED application. Ethyl cellulose with CsPbBr 3 quantum dots is applied with Sr 2 Si 5 N 8  : Eu 2+ red phosphor on an InGaN blue chip, achieving a highly efficient luminous efficacy of 67.93 lm W -1 under 20 mA current.

  1. Calcium and Superoxide-Mediated Pathways Converge to Induce Nitric Oxide-Dependent Apoptosis in Mycobacterium fortuitum-Infected Fish Macrophages.

    Science.gov (United States)

    Datta, Debika; Khatri, Preeti; Banerjee, Chaitali; Singh, Ambika; Meena, Ramavatar; Saha, Dhira Rani; Raman, Rajagopal; Rajamani, Paulraj; Mitra, Abhijit; Mazumder, Shibnath

    2016-01-01

    Mycobacterium fortuitum causes 'mycobacteriosis' in wide range of hosts although the mechanisms remain largely unknown. Here we demonstrate the role of calcium (Ca+2)-signalling cascade on M. fortuitum-induced apoptosis in headkidney macrophages (HKM) of Clarias sp. M. fortuitum could trigger intracellular-Ca+2 influx leading to the activation of calmodulin (CaM), protein kinase C alpha (PKCα) and Calmodulin kinase II gamma (CaMKIIg). Gene silencing and inhibitor studies established the role of CaM in M. fortuitum pathogenesis. We noted that CaMKIIg activation is regulated by CaM as well as PKCα-dependent superoxide anions. This is altogether first report of oxidised CaMKIIg in mycobacterial infections. Our studies with targeted-siRNA and pharmacological inhibitors implicate CaMKIIg to be pro-apoptotic and critical for the activation of extra-cellular signal regulated kinase 1/2 (ERK1/2). Inhibiting the ERK1/2 pathway attenuated nitric oxide synthase 2 (NOS2)-induced nitric oxide (NO) production. Conversely, inhibiting the NOS2-NO axis by specific-siRNA and inhibitors down-regulated ERK1/2 activation suggesting the crosstalk between ERK1/2 and NO is essential for pathogenesis induced by the bacterium. Silencing the NOS2-NO axis enhanced intracellular bacterial survival and attenuated caspase-8 mediated activation of caspase-3 in the infected HKM. Our findings unveil hitherto unknown mechanism of M. fortuitum pathogenesis. We propose that M. fortuitum triggers intracellular Ca+2 elevations resulting in CaM activation and PKCα-mediated superoxide generation. The cascade converges in common pathway mediated by CaMKIIg resulting in the activation of ERK1/2-NOS2 axis. The crosstalk between ERK1/2 and NO shifts the balance in favour of caspase dependent apoptosis of M. fortuitum-infected HKM.

  2. Enhancing NAD+ Salvage Pathway Reverts the Toxicity of Primary Astrocytes Expressing Amyotrophic Lateral Sclerosis-linked Mutant Superoxide Dismutase 1 (SOD1).

    Science.gov (United States)

    Harlan, Benjamin A; Pehar, Mariana; Sharma, Deep R; Beeson, Gyda; Beeson, Craig C; Vargas, Marcelo R

    2016-05-13

    Nicotinamide adenine dinucleotide (NAD(+)) participates in redox reactions and NAD(+)-dependent signaling pathways. Although the redox reactions are critical for efficient mitochondrial metabolism, they are not accompanied by any net consumption of the nucleotide. On the contrary, NAD(+)-dependent signaling processes lead to its degradation. Three distinct families of enzymes consume NAD(+) as substrate: poly(ADP-ribose) polymerases, ADP-ribosyl cyclases (CD38 and CD157), and sirtuins (SIRT1-7). Because all of the above enzymes generate nicotinamide as a byproduct, mammalian cells have evolved an NAD(+) salvage pathway capable of resynthesizing NAD(+) from nicotinamide. Overexpression of the rate-limiting enzyme in this pathway, nicotinamide phosphoribosyltransferase, increases total and mitochondrial NAD(+) levels in astrocytes. Moreover, targeting nicotinamide phosphoribosyltransferase to the mitochondria also enhances NAD(+) salvage pathway in astrocytes. Supplementation with the NAD(+) precursors nicotinamide mononucleotide and nicotinamide riboside also increases NAD(+) levels in astrocytes. Amyotrophic lateral sclerosis (ALS) is caused by the progressive degeneration of motor neurons in the spinal cord, brain stem, and motor cortex. Superoxide dismutase 1 (SOD1) mutations account for up to 20% of familial ALS and 1-2% of apparently sporadic ALS cases. Primary astrocytes isolated from mutant human superoxide dismutase 1-overexpressing mice as well as human post-mortem ALS spinal cord-derived astrocytes induce motor neuron death in co-culture. Increasing total and mitochondrial NAD(+) content in ALS astrocytes increases oxidative stress resistance and reverts their toxicity toward co-cultured motor neurons. Taken together, our results suggest that enhancing the NAD(+) salvage pathway in astrocytes could be a potential therapeutic target to prevent astrocyte-mediated motor neuron death in ALS. © 2016 by The American Society for Biochemistry and Molecular

  3. Enhancing NAD+ Salvage Pathway Reverts the Toxicity of Primary Astrocytes Expressing Amyotrophic Lateral Sclerosis-linked Mutant Superoxide Dismutase 1 (SOD1)*

    Science.gov (United States)

    Harlan, Benjamin A.; Pehar, Mariana; Sharma, Deep R.; Beeson, Gyda; Beeson, Craig C.; Vargas, Marcelo R.

    2016-01-01

    Nicotinamide adenine dinucleotide (NAD+) participates in redox reactions and NAD+-dependent signaling pathways. Although the redox reactions are critical for efficient mitochondrial metabolism, they are not accompanied by any net consumption of the nucleotide. On the contrary, NAD+-dependent signaling processes lead to its degradation. Three distinct families of enzymes consume NAD+ as substrate: poly(ADP-ribose) polymerases, ADP-ribosyl cyclases (CD38 and CD157), and sirtuins (SIRT1–7). Because all of the above enzymes generate nicotinamide as a byproduct, mammalian cells have evolved an NAD+ salvage pathway capable of resynthesizing NAD+ from nicotinamide. Overexpression of the rate-limiting enzyme in this pathway, nicotinamide phosphoribosyltransferase, increases total and mitochondrial NAD+ levels in astrocytes. Moreover, targeting nicotinamide phosphoribosyltransferase to the mitochondria also enhances NAD+ salvage pathway in astrocytes. Supplementation with the NAD+ precursors nicotinamide mononucleotide and nicotinamide riboside also increases NAD+ levels in astrocytes. Amyotrophic lateral sclerosis (ALS) is caused by the progressive degeneration of motor neurons in the spinal cord, brain stem, and motor cortex. Superoxide dismutase 1 (SOD1) mutations account for up to 20% of familial ALS and 1–2% of apparently sporadic ALS cases. Primary astrocytes isolated from mutant human superoxide dismutase 1-overexpressing mice as well as human post-mortem ALS spinal cord-derived astrocytes induce motor neuron death in co-culture. Increasing total and mitochondrial NAD+ content in ALS astrocytes increases oxidative stress resistance and reverts their toxicity toward co-cultured motor neurons. Taken together, our results suggest that enhancing the NAD+ salvage pathway in astrocytes could be a potential therapeutic target to prevent astrocyte-mediated motor neuron death in ALS. PMID:27002158

  4. Over-Expression of Copper/Zinc Superoxide Dismutase in the Median Preoptic Nucleus Attenuates Chronic Angiotensin II-Induced Hypertension in the Rat

    Directory of Open Access Journals (Sweden)

    John P. Collister

    2014-12-01

    Full Text Available The brain senses circulating levels of angiotensin II (AngII via circumventricular organs, such as the subfornical organ (SFO, and is thought to adjust sympathetic nervous system output accordingly via this neuro-hormonal communication. However, the cellular signaling mechanisms involved in these communications remain to be fully understood. Previous lesion studies of either the SFO, or the downstream median preoptic nucleus (MnPO have shown a diminution of the hypertensive effects of chronic AngII, without providing a clear explanation as to the intracellular signaling pathway(s involved. Additional studies have reported that over-expressing copper/zinc superoxide dismutase (CuZnSOD, an intracellular superoxide (O2·− scavenging enzyme, in the SFO attenuates chronic AngII-induced hypertension. Herein, we tested the hypothesis that overproduction of O2·− in the MnPO is an underlying mechanism in the long-term hypertensive effects of chronic AngII. Adenoviral vectors encoding human CuZnSOD (AdCuZnSOD or control vector (AdEmpty were injected directly into the MnPO of rats implanted with aortic telemetric transmitters for recording of arterial pressure. After a 3 day control period of saline infusion, rats were intravenously infused with AngII (10 ng/kg/min for ten days. Rats over-expressing CuZnSOD (n = 7 in the MnPO had a blood pressure increase of only 6 ± 2 mmHg after ten days of AngII infusion while blood pressure increased 21 ± 4 mmHg in AdEmpty-infected rats (n = 9. These results support the hypothesis that production of O2·− in the MnPO contributes to the development of chronic AngII-dependent hypertension.

  5. RAGE-dependent activation of gene expression of superoxide dismutase and vanins by AGE-rich extracts in mice cardiac tissue and murine cardiac fibroblasts.

    Science.gov (United States)

    Leuner, Beatrice; Ruhs, Stefanie; Brömme, Hans-Jürgen; Bierhaus, Angelika; Sel, Saadettin; Silber, Rolf-Edgar; Somoza, Veronika; Simm, Andreas; Nass, Norbert

    2012-10-01

    Advanced glycation end products (AGEs) are stable compounds formed from initial Maillard reaction products. They are considered as markers for ageing and often associated with age-related, degenerative diseases. Bread crust represents an established model for nutritional compounds rich in AGEs and is able to induce antioxidative defense genes such as superoxide dismutases and vanins in cardiac cells. The aim of this study was to investigate to what extend the receptor for AGEs (RAGE) contributes to this response. Signal transduction in response to bread crust extract was analysed in cardiac fibroblasts derived from C57/B6-NCrl (RAGE +/+) and the corresponding RAGE-knock out C57/B6-NCrl mouse strain (RAGE -/-). Activation of superoxide dismutases in animals was then analysed upon bread crust feeding in these two mice strains. Cardiac fibroblasts from RAGE -/- mice did not express RAGE, but the expression of AGER-1 and AGER-3 was up-regulated, whereas the expression of SR-B1 was down-regulated. RAGE -/- cells were less sensitive to BCE in terms of MAP-kinase phosphorylation and NF-κB reporter gene activation. Bread crust extract induced mRNA levels of MnSOD and Vnn-1 were also reduced in RAGE -/- cells, whereas Vnn-3 mRNA accumulation seemed to be RAGE receptor independent. In bread crust feeding experiments, RAGE -/- mice did not exhibit an activation of MnSOD-mRNA and -protein accumulation as observed for the RAGE +/+ animals. In conclusion, RAGE was clearly a major factor for the induction of antioxidant defense signals derived from bread crust in cardiac fibroblast and mice. Nevertheless higher doses of bread crust extract could overcome the RAGE dependency in cell cultures, indicating that additional mechanisms are involved in BCE-mediated activation of SOD and vanin expression.

  6. Targeting of superoxide dismutase to the liver results in anti-inflammatory effects in rats with fibrotic livers

    NARCIS (Netherlands)

    Swart, P J; Hirano, T; Kuipers, M E; Ito, Y; Smit, C; Hashida, M; Nishikawa, M; Beljaars, L; Meijer, D K; Poelstra, K

    1999-01-01

    Background/Aims: The rapid clearance from plasma and the limited uptake of superoxide dismutase (SOD) in the liver hampers the effectiveness of this enzyme in liver diseases. We therefore compared the pharmacokinetics and in vivo efficacy of SOD with two modified forms of this protein: SOD coupled

  7. 113Cd-NMR investigation of a cadmium-substituted copper, zinc-containing superoxide dismutase from yeast

    DEFF Research Database (Denmark)

    Kofod, Pauli; Bauer, Rogert; Danielsen, Eva

    1991-01-01

    113Cd nuclear magnetic resonance spectroscopy has been used to investigate the metal binding sites of cadmium-substituted copper,zinc-containing superoxide dismutase from baker's yeast. NMR signals were obtained for 113Cd(II) at the Cu site as well as for 113Cd(II) at the Zn site. The two subunits...

  8. Mitochondria-derived superoxide and voltage-gated sodium channels in baroreceptor neurons from chronic heart-failure rats.

    Science.gov (United States)

    Tu, Huiyin; Liu, Jinxu; Zhu, Zhen; Zhang, Libin; Pipinos, Iraklis I; Li, Yu-Long

    2012-01-01

    Our previous study has shown that chronic heart failure (CHF) reduces expression and activation of voltage-gated sodium (Na(v)) channels in baroreceptor neurons, which are involved in the blunted baroreceptor neuron excitability and contribute to the impairment of baroreflex in the CHF state. The present study examined the role of mitochondria-derived superoxide in the reduced Na(v) channel function in coronary artery ligation-induced CHF rats. CHF decreased the protein expression and activity of mitochondrial complex enzymes and manganese SOD (MnSOD) and elevated the mitochondria-derived superoxide level in the nodose neurons compared with those in sham nodose neurons. Adenoviral MnSOD (Ad.MnSOD) gene transfection (50 multiplicity of infection) into the nodose neurons normalized the MnSOD expression and reduced the elevation of mitochondrial superoxide in the nodose neurons from CHF rats. Ad.MnSOD also partially reversed the reduced protein expression and current density of the Na(v) channels and the suppressed cell excitability (the number of action potential and the current threshold for inducing action potential) in aortic baroreceptor neurons from CHF rats. Data from the present study indicate that mitochondrial dysfunction, including decreased protein expression and activity of mitochondrial complex enzymes and MnSOD and elevated mitochondria-derived superoxide, contributes to the reduced Na(v) channel activation and cell excitability in the aortic baroreceptor neurons in CHF rats.

  9. Crystal Structure of Cu/Zn Superoxide Dismutase from Taenia Solium Reveals Metal-mediated Self-assembly

    Energy Technology Data Exchange (ETDEWEB)

    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.

  10. Superoxide anions and hydrogen peroxide induce hepatocyte death by different mechanisms : Involvement of JNK and ERK MAP kinases

    NARCIS (Netherlands)

    Conde de la Rosa, L; Schoemaker, MH; Vrenken, TE; Buist-Homan, M; Havinga, R; Jansen, PLM; Moshage, H

    Background/Aims: In liver diseases, reactive oxygen species (ROS) are involved in cell death and liver injury, but the mechanisms are not completely elucidated. To elucidate the mechanisms of hepatocyte cell death induced by the ROS superoxide anions and hydrogen peroxide, primary cultures of

  11. Superoxide anions and hydrogen peroxide induce hepatocyte death by different mechanisms: involvement of JNK and ERK MAP kinases

    NARCIS (Netherlands)

    Conde de la Rosa, Laura; Schoemaker, Marieke H.; Vrenken, Titia E.; Buist-Homan, Manon; Havinga, Rick; Jansen, Peter L. M.; Moshage, Han

    2006-01-01

    BACKGROUND/AIMS: In liver diseases, reactive oxygen species (ROS) are involved in cell death and liver injury, but the mechanisms are not completely elucidated. To elucidate the mechanisms of hepatocyte cell death induced by the ROS superoxide anions and hydrogen peroxide, primary cultures of

  12. Nitroxyl Modified Tobacco Mosaic Virus as a Metal-Free High-Relaxivity MRI and EPR Active Superoxide Sensor.

    Science.gov (United States)

    Dharmarwardana, Madushani; Martins, André F; Chen, Zhuo; Palacios, Philip M; Nowak, Chance M; Welch, Raymond P; Li, Shaobo; Luzuriaga, Michael A; Bleris, Leonidas; Pierce, Brad S; Sherry, A Dean; Gassensmith, Jeremiah J

    2018-05-29

    Superoxide overproduction is known to occur in multiple disease states requiring critical care; yet, noninvasive detection of superoxide in deep tissue remains a challenge. Herein, we report a metal-free magnetic resonance imaging (MRI) and electron paramagnetic resonance (EPR) active contrast agent prepared by "click conjugating" paramagnetic organic radical contrast agents (ORCAs) to the surface of tobacco mosaic virus (TMV). While ORCAs are known to be reduced in vivo to an MRI/EPR silent state, their oxidation is facilitated specifically by reactive oxygen species-in particular, superoxide-and are largely unaffected by peroxides and molecular oxygen. Unfortunately, single molecule ORCAs typically offer weak MRI contrast. In contrast, our data confirm that the macromolecular ORCA-TMV conjugates show marked enhancement for T 1 contrast at low field (<3.0 T) and T 2 contrast at high field (9.4 T). Additionally, we demonstrated that the unique topology of TMV allows for a "quenchless fluorescent" bimodal probe for concurrent fluorescence and MRI/EPR imaging, which was made possible by exploiting the unique inner and outer surface of the TMV nanoparticle. Finally, we show TMV-ORCAs do not respond to normal cellular respiration, minimizing the likelihood for background, yet still respond to enzymatically produced superoxide in complicated biological fluids like serum.

  13. Acute Superoxide Radical Scavenging Reduces Blood Pressure but Does Not Influence Kidney Function in Hypertensive Rats with Postischemic Kidney Injury

    Directory of Open Access Journals (Sweden)

    Zoran Miloradović

    2014-01-01

    Full Text Available Acute kidney injury (AKI is associated with significant morbidity and mortality in hypertensive surroundings. We investigated superoxide radical molecules influence on systemic haemodynamic and kidney function in spontaneously hypertensive rats (SHR with induced postischemic AKI. Experiment was performed in anesthetized adult male SHR. The right kidney was removed, and left renal artery was subjected to ischemia by clamping for 40 minutes. The treated group received synthetic superoxide dismutase mimetic TEMPOL in the femoral vein 5 minutes before, during, and 175 minutes after the period of reperfusion, while the control AKI group received the vehicle via the same route. All parameters were measured 24 h after renal reperfusion. TEMPOL treatment significantly decreased mean arterial pressure and total peripheral resistance P<0.05 compared to AKI control. It also increased cardiac output and catalase activity P<0.05. Lipid peroxidation and renal vascular resistance were decreased in TEMPOL P<0.05. Plasma creatinine and kidney morphological parameters were unchanged among TEMPOL treated and control groups. Our study shows that superoxide radicals participate in haemodynamic control, but acute superoxide scavenging is ineffective in glomerular and tubular improvement, probably due to hypertension-induced strong endothelial dysfunction which neutralizes beneficial effects of O2− scavenging.

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

    Science.gov (United States)

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

    2014-11-01

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

  15. Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior

    Energy Technology Data Exchange (ETDEWEB)

    Beltrán-Partida, Ernesto [Department of Biomaterials, Dental Materials and Tissue Engineering, Faculty of Dentistry Mexicali, Autonomous University of Baja California, Av. Zotoluca and Chinampas St., 21040 Mexicali, Baja California (Mexico); Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Valdez-Salas, Benjamín, E-mail: benval@uabc.edu.mx [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Escamilla, Alan; Curiel, Mario [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Valdez-Salas, Ernesto [Ixchel Medical Centre, Av. Bravo y Obregón, 21000 Mexicali, Baja California (Mexico); Nedev, Nicola [Department of Corrosion and Materials, Engineering Institute, Autonomous University of Baja California, Blvd. Benito Juarez and Normal St., 21280 Mexicali, Baja California (Mexico); Bastidas, Jose M. [National Centre for Metallurgical Research, CSIC, Av. Gregorio del Amo 8, 28040 Madrid (Spain)

    2016-03-01

    Amorphous titanium dioxide (TiO{sub 2}) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability. - Highlights: • The effect of super-oxidized water cleaning was studied on Ti6Al4V nanotubes. • Super oxidized-water cleaning caused a decline in S. aureus viability. • Osteoblast behavior was not disrupted after super-oxidized water disinfection. • Super-oxidized water is suggested as a cleaning protocol for TiO{sub 2} nanotubes.

  16. Disinfection of titanium dioxide nanotubes using super-oxidized water decrease bacterial viability without disrupting osteoblast behavior

    International Nuclear Information System (INIS)

    Beltrán-Partida, Ernesto; Valdez-Salas, Benjamín; Escamilla, Alan; Curiel, Mario; Valdez-Salas, Ernesto; Nedev, Nicola; Bastidas, Jose M.

    2016-01-01

    Amorphous titanium dioxide (TiO_2) nanotubes (NTs) on Ti6Al4V alloy were synthesized by anodization using a commercially available super-oxidized water (SOW). The NT surfaces were sterilized by ultraviolet (UV) irradiation and disinfected using SOW. The adhesion and cellular morphology of pig periosteal osteoblast (PPO) cells and the behavior of Staphylococcus aureus (S. aureus) cultured on the sterilized and disinfected surfaces were investigated. A non-anodized Ti6Al4V disc sterilized by UV irradiation (without SOW) was used as control. The results of this study reveal that the adhesion, morphology and filopodia development of PPO cells in NTs are dramatically improved, suggesting that SOW cleaning may not disrupt the benefits obtained by NTs. Significantly decreased bacterial viability in NTs after cleaning with SOW and comparing with non-cleaned NTs was seen. The results suggest that UV and SOW could be a recommendable method for implant sterilization and disinfection without altering osteoblast behavior while decreasing bacterial viability. - Highlights: • The effect of super-oxidized water cleaning was studied on Ti6Al4V nanotubes. • Super oxidized-water cleaning caused a decline in S. aureus viability. • Osteoblast behavior was not disrupted after super-oxidized water disinfection. • Super-oxidized water is suggested as a cleaning protocol for TiO_2 nanotubes.

  17. Discussion of “Prediction intervals for short-term wind farm generation forecasts” and “Combined nonparametric prediction intervals for wind power generation”

    DEFF Research Database (Denmark)

    Pinson, Pierre; Tastu, Julija

    2014-01-01

    A new score for the evaluation of interval forecasts, the so-called coverage width-based criterion (CWC), was proposed and utilized.. This score has been used for the tuning (in-sample) and genuine evaluation (out-ofsample) of prediction intervals for various applications, e.g., electric load [1......], electricity prices [2], general purpose prediction [3], and wind power generation [4], [5]. Indeed, two papers by the same authors appearing in the IEEE Transactions On Sustainable Energy employ that score and use it to conclude on the comparative quality of alternative approaches to interval forecasting...

  18. Ghrelin-related peptides do not modulate vasodilator nitric oxide production or superoxide levels in mouse systemic arteries.

    Science.gov (United States)

    Ku, Jacqueline M; Sleeman, Mark W; Sobey, Christopher G; Andrews, Zane B; Miller, Alyson A

    2016-04-01

    The ghrelin gene is expressed in the stomach where it ultimately encodes up to three peptides, namely, acylated ghrelin, des-acylated ghrelin and obestatin, which all have neuroendocrine roles. Recently, the authors' reported that these peptides have important physiological roles in positively regulating vasodilator nitric oxide (NO) production in the cerebral circulation, and may normally suppress superoxide production by the pro-oxidant enzyme, Nox2-NADPH oxidase. To date, the majority of studies using exogenous peptides infer that they may have similar roles in the systemic circulation. Therefore, this study examined whether exogenous and endogenous ghrelin-related peptides modulate NO production and superoxide levels in mouse mesenteric arteries and/or thoracic aorta. Using wire myography, it was found that application of exogenous acylated ghrelin, des-acylated ghrelin or obestatin to mouse thoracic aorta or mesenteric arteries failed to elicit a vasorelaxation response, whereas all three peptides elicited vasorelaxation responses of rat thoracic aorta. Also, none of the peptides modulated mouse aortic superoxide levels as measured by L-012-enhanced chemiluminescence. Next, it was found that NO bioactivity and superoxide levels were unaffected in the thoracic aorta from ghrelin-deficient mice when compared with wild-type mice. Lastly, using novel GHSR-eGFP reporter mice in combination with double-labelled immunofluorescence, no evidence was found for the growth hormone secretagogue receptor (GHSR1a) in the throracic aorta, which is the only functional ghrelin receptor identified to date. Collectively these findings demonstrate that, in contrast to systemic vessels of other species (e.g. rat and human) and mouse cerebral vessels, ghrelin-related peptides do not modulate vasodilator NO production or superoxide levels in mouse systemic arteries. © 2016 John Wiley & Sons Australia, Ltd.

  19. Pyrrolidine dithiocarbamate inhibits superoxide anion-induced pain and inflammation in the paw skin and spinal cord by targeting NF-κB and oxidative stress.

    Science.gov (United States)

    Pinho-Ribeiro, Felipe A; Fattori, Victor; Zarpelon, Ana C; Borghi, Sergio M; Staurengo-Ferrari, Larissa; Carvalho, Thacyana T; Alves-Filho, Jose C; Cunha, Fernando Q; Cunha, Thiago M; Casagrande, Rubia; Verri, Waldiceu A

    2016-06-01

    We evaluated the effect of pyrrolidine dithiocarbamate (PDTC) in superoxide anion-induced inflammatory pain. Male Swiss mice were treated with PDTC and stimulated with an intraplantar or intraperitoneal injection of potassium superoxide, a superoxide anion donor. Subcutaneous PDTC treatment attenuated mechanical hyperalgesia, thermal hyperalgesia, paw oedema and leukocyte recruitment (neutrophils and macrophages). Intraplantar injection of superoxide anion activated NF-κB and increased cytokine production (IL-1β, TNF-α and IL-10) and oxidative stress (nitrite and lipid peroxidation levels) at the primary inflammatory foci and in the spinal cord (L4-L6). PDTC treatment inhibited superoxide anion-induced NF-κB activation, cytokine production and oxidative stress in the paw and spinal cord. Furthermore, intrathecal administration of PDTC successfully inhibited superoxide anion-induced mechanical hyperalgesia, thermal hyperalgesia and inflammatory response in peripheral foci (paw). These results suggest that peripheral stimulus with superoxide anion activates the local and spinal cord oxidative- and NF-κB-dependent inflammatory nociceptive mechanisms. PDTC targets these events, therefore, inhibiting superoxide anion-induced inflammatory pain in mice.

  20. Stuttering interneurons generate fast and robust inhibition onto projection neurons with low capacity of short term modulation in mouse lateral amygdala.

    Directory of Open Access Journals (Sweden)

    Chen Song

    Full Text Available The stuttering interneurons (STi represent one minor subset of interneuron population and exhibit characteristic stuttering firing upon depolarization current injection. While it has been long held that the GABAergic inhibitory transmission largely varies with the subtype identity of presynaptic interneurons, whether such a rule also applies to STi is largely unknown. Here, by paired recording of interneuron and their neighboring projection neuron in lateral amygdala, we found that relative to the fast spiking and late spiking interneurons, the STi-evoked unitary postsynaptic currents onto the projection neurons had markedly larger amplitude, shorter onset latency and faster rising and decay kinetics. The quantal content and the number of vesicles in the readily releasable pool were also larger in synapses made by STi versus other interneurons. Moreover, the short-term plasticity, as reflected by the paired pulse depression and depolarization-induced suppression of inhibition, was the least prominent in the output synapses of STi. Thus, the fast and robust inhibition together with its low capacity of short term modulation may suggest an important role for STi in preventing the overexcitation of the projection neurons and thus gating the information traffic in amygdala.

  1. NADPH oxidase 4-derived superoxide mediates flow-stimulated NKCC2 activity in thick ascending limbs.

    Science.gov (United States)

    Saez, Fara; Hong, Nancy J; Garvin, Jeffrey L

    2018-05-01

    Luminal flow augments Na + reabsorption in the thick ascending limb more than can be explained by increased ion delivery. This segment reabsorbs 30% of the filtered load of Na + , playing a key role in its homeostasis. Whether flow elevations enhance Na + -K + -2Cl - cotransporter (NKCC2) activity and the second messenger involved are unknown. We hypothesized that raising luminal flow augments NKCC2 activity by enhancing superoxide ([Formula: see text]) production by NADPH oxidase 4 (NOX4). NKCC2 activity was measured in thick ascending limbs perfused at either 5 or 20 nl/min with and without inhibitors of [Formula: see text] production. Raising luminal flow from 5 to 20 nl/min enhanced NKCC2 activity from 4.8 ± 0.9 to 6.3 ± 1.2 arbitrary fluorescent units (AFU)/s. Maintaining flow at 5 nl/min did not alter NKCC2 activity. The superoxide dismutase mimetic manganese (III) tetrakis (4-benzoic acid) porphyrin chloride blunted NKCC2 activity from 3.5 ± 0.4 to 2.5 ± 0.2 AFU/s when flow was 20 nl/min but not 5 nl/min. When flow was 20 nl/min, NKCC2 activity showed no change with time. The selective NOX1/4 inhibitor GKT-137831 blunted NKCC2 activity when thick ascending limbs were perfused at 20 nl/min from 7.2 ± 1.1 to 4.5 ± 0.8 AFU/s but not at 5 nl/min. The inhibitor also prevented luminal flow from elevating [Formula: see text] production. Allopurinol, a xanthine oxidase inhibitor, had no effect on NKCC2 activity when flow was 20 nl/min. Tetanus toxin prevents flow-induced stimulation of NKCC2 activity. We conclude that elevations in luminal flow enhance NaCl reabsorption in thick ascending limbs by stimulating NKCC2 via NOX4 activation and increased [Formula: see text]. NKCC2 activation is primarily the result of insertion of new transporters in the membrane.

  2. Using superoxide dismutase/catalase mimetics to manipulate the redox environment of neural precursor cells

    International Nuclear Information System (INIS)

    Limoli, C. L.; Giedzinski, E.; Baure, J.; Doctrow, S. R.; Rola, R.; Fike, J. R.

    2006-01-01

    Past work has shown that neural precursor cells are predisposed to redox sensitive changes, and that oxidative stress plays a critical role in the acute and persistent changes that occur within the irradiated CNS. Irradiation leads to a marked rise in reactive oxygen species (ROS) that correlates with oxidative endpoints in vivo and reductions in neuro-genesis. To better understand the impact of oxidative stress on neural precursor cells, and to determine if radiation-induced oxidative damage and precursor cell loss after irradiation could be reduced, a series of antioxidant compounds (EUK-134, EUK-163, EUK-172, EUK-189) were tested, three of which possess both superoxide dismutase (SOD) and catalase activities and one (EUK-163) whose only significant activity is SOD. Our results show that these SOD/catalase mimetics apparently increase the oxidation of a ROS-sensitive fluorescent indicator dye, particularly after short (12 h) treatments, but that longer treatments (24 h) decrease oxidation attributable to radiation-induced ROS. Similarly, other studies found that cells incubated with CuZnSOD showed some increase in intracellular ROS levels. Subsequent data suggested that the dye-oxidising capabilities of the EUK compounds were linked to differences in their catalase activity and, most likely, their ability to catalyse per-oxidative pathways. In unirradiated mice, the EUK-134 analogue induced some decrease of proliferating precursor cells and immature neurons 48 h after radiation, an effect that may be attributable to cytotoxicity and/or inhibition of precursor proliferation. In irradiated mice, a single injection of EUK-134 was not found to be an effective radioprotector at acute times (48 h). The present results support continued development of our in vitro model as a tool for predicting certain in vivo responses, and suggest that in some biological systems the capability to scavenge superoxide but produce excess H 2 O 2 , as is known for CuZnSOD, may be

  3. Serotonin disturbs colon epithelial tolerance of commensal E. coli by increasing NOX2-derived superoxide.

    Science.gov (United States)

    Banskota, Suhrid; Regmi, Sushil Chandra; Gautam, Jaya; Gurung, Pallavi; Lee, Yu-Jeong; Ku, Sae Kwang; Lee, Jin-Hyung; Lee, Jintae; Chang, Hyeun Wook; Park, Sang Joon; Kim, Jung-Ae

    2017-05-01

    Adherent-invasive E. coli colonization and Toll-like receptor (TLR) expression are increased in the gut of inflammatory bowel disease (IBD) patients. However, the underlying mechanism of such changes has not been determined. In the current study, it was examined whether gut serotonin (5-hydroxytryptamine, 5-HT) can induce adherent-invasive E. coli colonization and increase TLR expression. In a co-culture system, commensal E. coli strain (BW25113, BW) adhered minimally to colon epithelial cells, but this was significantly enhanced by 5-HT to the level of a pathogenic strain (EDL933). Without inducing bacterial virulence, such as, biofilm formation, 5-HT enhanced BW-induced signaling in colon epithelial cells, that is, NADPH oxidase (NOX)-dependent superoxide production, the up-regulations of IL-8, TLR2, TLR4, and ICAM-1, and the down-regulations of E-cadherin and claudin-2. In a manner commensurate with these gene modulations, BW induced an increase in NF-κB and a decrease in GATA reporter signals in colon epithelial cells. However, 5-HT-enhanced BW adhesion and colon epithelial responses were blocked by knock-down of NOX2, TLR2, or TLR4. In normal mice, 5-HT induced the invasion of BW into gut submucosa, and the observed molecular changes were similar to those observed in vitro, except for significant increases in TNFα and IL-1β, and resulted in death. In dextran sulfate sodium-induced colitis mice (an IBD disease model), in which colonic 5-HT levels were markedly elevated, BW administration induced death in along with large amount of BW invasion into colon submucosa, and time to death was negatively related to the amount of BW injected. Taken together, our results demonstrate that 5-HT induces the invasion of commensal E. coli into gut submucosa by amplifying commensal bacteria-induced epithelial signaling (superoxide production and the inductions of NOX2 and TLR2/TLR4). The authors suggest that these changes may constitute the molecular basis for the

  4. Early superoxide scavenging accelerates renal microvascular rarefaction and damage in the stenotic kidney.

    Science.gov (United States)

    Kelsen, Silvia; He, Xiaochen; Chade, Alejandro R

    2012-08-15

    Renal artery stenosis (RAS), the main cause of chronic renovascular disease (RVD), is associated with significant oxidative stress. Chronic RVD induces renal injury partly by promoting renal microvascular (MV) damage and blunting MV repair in the stenotic kidney. We tested the hypothesis that superoxide anion plays a pivotal role in MV dysfunction, reduction of MV density, and progression of renal injury in the stenotic kidney. RAS was induced in 14 domestic pigs and observed for 6 wk. Seven RAS pigs were chronically treated with the superoxide dismutase mimetic tempol (RAS+T) to reduce oxidative stress. Single-kidney hemodynamics and function were quantified in vivo using multidetector computer tomography (CT) and renal MV density was quantified ex vivo using micro-CT. Expression of angiogenic, inflammatory, and apoptotic factors was measured in renal tissue, and renal apoptosis and fibrosis were quantified in tissue sections. The degree of RAS and blood pressure were similarly increased in RAS and RAS+T. Renal blood flow (RBF) and glomerular filtration rate (GFR) were reduced in the stenotic kidney (280.1 ± 36.8 and 34.2 ± 3.1 ml/min, P < 0.05 vs. control). RAS+T kidneys showed preserved GFR (58.5 ± 6.3 ml/min, P = not significant vs. control) but a similar decreases in RBF (293.6 ± 85.2 ml/min) and further decreases in MV density compared with RAS. These changes were accompanied by blunted angiogenic signaling and increased apoptosis and fibrosis in the stenotic kidney of RAS+T compared with RAS. The current study shows that tempol administration provided limited protection to the stenotic kidney. Despite preserved GFR, renal perfusion was not improved by tempol, and MV density was further reduced compared with untreated RAS, associated with increased renal apoptosis and fibrosis. These results suggest that a tight balance of the renal redox status is necessary for a normal MV repair response to injury, at least at the early stage of RVD, and raise caution

  5. Corrosion products behavior and source term reduction : guidelines and feedback for EDF PWRs, concerning the B/Li coordinations and steam generators replacement

    International Nuclear Information System (INIS)

    Taunier, S.; Wintergerst, M.; De Bouvier, O.; Pokor, C.; Carrette, F.; Toivonen, A.; Ranchoux, G.; Bretelle, J.L.

    2010-01-01

    The release of corrosion products by the various components of the primary system into the cooling water may induce some issues on reactor control and on radiation dose rates. Heavy crud deposits may occur on the fuel clad surface and lead to axial offset anomalies (AOA) and in extreme cases, to fuel failures. This deposition phenomenon is apparently associated with steam generator (SG) materials, water chemistry, thermal hydraulics, fuel cleaning or reactor operation history. Moreover, under intense neutron flux, these corrosion products are activated and their dissolution and deposition in the primary system may further increase the out-of-core radioactive contamination and result in radiation dose rates. Several ways are available to reduce the amount and transportation of corrosion products in the primary coolant. A first approach is related to the materials used in the primary system. As one of the main contributors to the release of corrosion products, the Ni-alloy used for the steam generators (SG) tubes has to be properly selected, manufactured and 'passivated'. The paper presents the recent feedback regarding the primary coolant chemistry and radiochemistry after Steam Generators Replacements (SGR). The modified startup procedure of the plant after SGR is also described, as well as its potential benefits on the primary coolant behavior. A second approach is to optimize the primary water chemistry to reduce the release and the transport of the corrosion products through the pH control. This kind of control is important, since higher fuel enrichments are currently used in our reactors, in order to get longer production cycles through higher burn-ups. To ensure the core reactivity control in the PWRs, the concentration of boric acid is increased in the primary water at the beginning of cycle (BOC). As a consequence, the resulting lower pH can induce a higher release of corrosion products from the steam generators. That is why, to keep an almost

  6. Effects of Short-Term Biosolarization Using Mature Compost and Industrial Tomato Waste Amendments on the Generation and Persistence of Biocidal Soil Conditions and Subsequent Tomato Growth.

    Science.gov (United States)

    Achmon, Yigal; Sade, Nir; Wilhelmi, María Del Mar Rubio; Fernández-Bayo, Jesus D; Harrold, Duff R; Stapleton, James J; VanderGheynst, Jean S; Blumwald, Eduardo; Simmons, Christopher W

    2018-06-06

    Conventional solarization and biosolarization with mature compost and tomato processing residue amendments were compared with respect to generation of pesticidal conditions and tomato ( Solanum lycopersicum L.) plant growth in treated soils. Soil oxygen depletion was examined as a response that has previously not been measured across multiple depths during biosolarization. For biosolarized soil, volatile fatty acids were found to accumulate concurrent with oxygen depletion, and the magnitude of these changes varied by soil depth. Two consecutive years of experimentation showed varying dissipation of volatile fatty acids from biosolarized soils post-treatment. When residual volatile fatty acids were detected in the biosolarized soil, fruit yield did not significantly differ from plants grown in solarized soil. However, when there was no residual volatile fatty acids in the soil at the time of planting, plants grown in biosolarized soil showed a significantly greater vegetation amount, fruit quantity, and fruit ripening than those of plants grown in solarized soil.

  7. Requirements for a long-term safety certification for chemotoxic substances stored in a final storage facility for high radioactive and heat-generating radioactive waste in rock salt formations

    International Nuclear Information System (INIS)

    Tholen, M.; Hippler, J.; Herzog, C.

    2007-01-01

    Within the scope of a project funded by the German Federal Ministry of Economics and Technology (Bundesministerium fuer Wirtschaft und Technologie, BMWi), a safety certification concept for a future permanent final storage for high radioactive and heat-generating radioactive waste (HAW disposal facility) in rock salt formations is being prepared. For a reference concept, compliance with safety requirements in regard to operational safety as well as radiological and non-radiological protection objectives related to long-term safety, including ground water protection, will be evaluated. This paper deals with the requirements for a long-term safety certification for the purpose of protecting ground water from chemotoxic substances. In particular, longterm safety certifications for the permanent disposal of radioactive waste in a HAW disposal facility in rock salt formations and for the dumping of hazardous waste in underground storage facilities in rock salt formations are first discussed, followed by an evaluation as to whether these methods can be applied to the long-term safety certification for chemotoxic substances. The authors find it advisable to apply the long-term safety certification for underground storage facilities to the long-term safety certification for chemotoxic substances stored in a HAW disposal facility in rock salt formations. In conclusion, a corresponding certification concept is introduced. (orig.)

  8. The “Weather Intelligence for Renewable Energies” Benchmarking Exercise on Short-Term Forecasting of Wind and Solar Power Generation

    <