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

PubMed

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

2018-05-01

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

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

PubMed

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

2016-06-01

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

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

PubMed

Moslehi, Maryam; Yazdanparast, Razieh

2013-07-01

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

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

PubMed

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

2002-05-01

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

Enhanced superoxide anion production in activated peritoneal macrophages from English sole (Pleuronectes vetulus) exposed to PACs

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

Clemons, E.; Arkoosh, M.; Casillas, E.

In fish, as in mammals, macrophages play a vital role in the destruction of infective organisms. The purpose of this study was to determine if peritoneal macrophages (M{O}s) from English sole (Pleuronectes vetulus), a marine benthic fish, have an altered ability to produce cytotoxic reactive oxygen intermediates (ROIs) after exposure to polycyclic aromatic compounds (PACs). ROIs are the principle product of M{O}s used to destroy engulfed organisms. Assay conditions, including the concentration of M{O}s, type of in vitro stimulant, tissue culture media, and incubation time were optimized to measure the production of superoxide anion (O{sub 2}{minus}), the progenitor ROI, inmore » English sole M{O}s. English sole were injected with an organic solvent extract of a PAH-contaminated sediment, equivalent to 20g sediment/kg fish, via their dorsal lymphatic sinus, and peritoneal M{O}s were harvested on days 1, 3, 5, 7, and 14 post injection. Activated peritoneal M{O}s from English sole injected with the sediment extract produced significantly more superoxide radicals after stimulation in vitro with either opsonized zymosan (OZ) or phorbol myristate acetate (PMA) than the vehicle injected or control fish. Specifically, activated peritoneal M{O}s stimulated with PMA in vitro produced greater amounts (compared to controls) of O{sub 2}{minus} on days 7 and 14 after exposure, whereas the same cells stimulated with OZ showed heightened production only on day 7 after exposure. No differences in the basal amounts of O{sub 2}{minus} production from activated peritoneal M{O}s between the treatment groups were observed. This study shows that exposure of English sole to PACs altered production of O{sub 2}{minus} by macrophages, however, the consequence to the immunocompetence of exposed fish remains to be elucidated.« less

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

PubMed

Yu, Zhanjiang; Yang, Xiaoda; Wang, Kui

2006-06-01

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

A superoxide anion-scavenger, 1,3-selenazolidin-4-one suppresses serum deprivation-induced apoptosis in PC12 cells by activating MAP kinase

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

Nishina, Atsuyoshi, E-mail: nishina@yone.ac.jp; Kimura, Hirokazu; Kozawa, Kunihisa

Synthetic organic selenium compounds, such as ebselen, may show glutathione peroxidase-like antioxidant activity and have a neurotrophic effect. We synthesized 1,3-selenazolidin-4-ones, new types of synthetic organic selenium compounds (five-member ring compounds), to study their possible applications as antioxidants or neurotrophic-like molecules. Their superoxide radical scavenging effects were assessed using the quantitative, highly sensitive method of real-time kinetic chemiluminescence. At 166 {mu}M, the O{sub 2}{sup -} scavenging activity of 1,3-selenazolidin-4-ones ranged from 0 to 66.2%. 2-[3-(4-Methoxyphenyl)-4-oxo-1,3-selenazolidin-2-ylidene]malononitrile (compound b) showed the strongest superoxide anion-scavenging activity among the 6 kinds of 2-methylene-1,3-selenazolidin-4-ones examined. Compound b had a 50% inhibitory concentration (IC{sub 50}) atmore » 92.4 {mu}M and acted as an effective and potentially useful O{sub 2}{sup -} scavenger in vitro. The effect of compound b on rat pheochromocytome cell line PC12 cells was compared with that of ebselen or nerve growth factor (NGF) by use of the MTT [3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] assay. When ebselen was added at 100 {mu}M or more, toxicity toward PC12 cells was evident. On the contrary, compound b suppressed serum deprivation-induced apoptosis in PC12 cells more effectively at a concentration of 100 {mu}M. The activity of compound b to phosphorylate mitogen-activated protein kinase/extracellular signal-regulated protein kinase (ERK) 1/2 (MAP kinase) in PC12 cells was higher than that of ebselen, and the former at 100 {mu}M induced the phosphorylation of MAP kinase to a degree similar to that induced by NGF. From these results, we conclude that this superoxide anion-scavenger, compound b, suppressed serum deprivation-induced apoptosis by promoting the phosphorylation of MAP kinase. -- Highlights: Black-Right-Pointing-Pointer We newly synthesized 1,3-selenazolidin-4

Aerobic photoreactivity of synthetic eumelanins and pheomelanins: generation of singlet oxygen and superoxide anion.

PubMed

Szewczyk, Grzegorz; Zadlo, Andrzej; Sarna, Michal; Ito, Shosuke; Wakamatsu, Kazumasa; Sarna, Tadeusz

2016-11-01

In this work, we examined photoreactivity of synthetic eumelanins, formed by autooxidation of DOPA, or enzymatic oxidation of 5,6-dihydroxyindole-2-carboxylic acid and synthetic pheomelanins obtained by enzymatic oxidation of 5-S-cysteinyldopa or 1:1 mixture of DOPA and cysteine. Electron paramagnetic resonance oximetry and spin trapping were used to measure oxygen consumption and formation of superoxide anion induced by irradiation of melanin with blue light, and time-resolved near-infrared luminescence was employed to determine the photoformation of singlet oxygen between 300 and 600 nm. Both superoxide anion and singlet oxygen were photogenerated by the synthetic melanins albeit with different efficiency. At 450-nm, quantum yield of singlet oxygen was very low (~10 -4 ) but it strongly increased in the UV region. The melanins quenched singlet oxygen efficiently, indicating that photogeneration and quenching of singlet oxygen may play an important role in aerobic photochemistry of melanin pigments and could contribute to their photodegradation and photoaging. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Superoxide anion radicals induce IGF-1 resistance through concomitant activation of PTP1B and PTEN

PubMed Central

Singh, Karmveer; Maity, Pallab; Krug, Linda; Meyer, Patrick; Treiber, Nicolai; Lucas, Tanja; Basu, Abhijit; Kochanek, Stefan; Wlaschek, Meinhard; Geiger, Hartmut; Scharffetter-Kochanek, Karin

2015-01-01

The evolutionarily conserved IGF-1 signalling pathway is associated with longevity, metabolism, tissue homeostasis, and cancer progression. Its regulation relies on the delicate balance between activating kinases and suppressing phosphatases and is still not very well understood. We report here that IGF-1 signalling in vitro and in a murine ageing model in vivo is suppressed in response to accumulation of superoxide anions () in mitochondria, either by chemical inhibition of complex I or by genetic silencing of -dismutating mitochondrial Sod2. The -dependent suppression of IGF-1 signalling resulted in decreased proliferation of murine dermal fibroblasts, affected translation initiation factors and suppressed the expression of α1(I), α1(III), and α2(I) collagen, the hallmarks of skin ageing. Enhanced led to activation of the phosphatases PTP1B and PTEN, which via dephosphorylation of the IGF-1 receptor and phosphatidylinositol 3,4,5-triphosphate dampened IGF-1 signalling. Genetic and pharmacologic inhibition of PTP1B and PTEN abrogated -induced IGF-1 resistance and rescued the ageing skin phenotype. We thus identify previously unreported signature events with , PTP1B, and PTEN as promising targets for drug development to prevent IGF-1 resistance-related pathologies. PMID:25520316

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

PubMed

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

2012-11-15

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

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

PubMed Central

2012-01-01

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

In vitro knockout of human p47phox blocks superoxide anion production and LDL oxidation by activated human monocytes.

PubMed

Bey, E A; Cathcart, M K

2000-03-01

We previously reported that superoxide dismutase (SOD) blocked human monocyte oxidation of LDL and therefore concluded that superoxide anion (O(2)(.-)) was required for oxidation. Others, however, have suggested that SOD may inhibit by mechanisms alternative to the dismutation of O(2)(.-). This study definitively addresses the involvement of O(2)(.-) in monocyte oxidation of LDL. Using an antisense ODN designed to target p47phox mRNA, we found that treatment of monocytes with antisense ODN caused a substantial and selective decrease in expression of p47phox protein, whereas sense ODN was without effect. Corresponding functional assays demonstrated that antisense ODN inhibited production of O(2)(.-). As sense ODN caused no inhibition of O(2)(.-) production, these results suggested that inhibition of p47phox expression caused reduction in O(2)(.-) production. Evaluation of the contribution of O(2)(.-) production to monocyte-mediated oxidation of LDL lipids confirmed that O(2)(.-) production is required for LDL lipid oxidation as antisense ODN treatment significantly inhibited LDL oxidation whereas sense ODN treatment caused no inhibition. This is the first report of the reduction of NADPH oxidase activity in intact human monocytes by directly targeting the mRNA of a significant member of this enzyme complex. Our results provide convincing data that O(2)(.-) is indeed required for monocyte-mediated LDL oxidation.

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

PubMed Central

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

2014-01-01

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

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

PubMed

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

2015-01-01

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

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

PubMed

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

2008-08-01

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

Structural characteristics for superoxide anion radical scavenging and productive activities of green tea polyphenols including proanthocyanidin dimers.

PubMed

Sato, Masashi; Toyazaki, Hajime; Yoshioka, Yu; Yokoi, Nobutoshi; Yamasaki, Toru

2010-01-01

The purpose of this paper is to report structural characteristics for superoxide anion radical (O(2(-))) scavenging and productive activities of green tea polyphenols. (-)-Epicatechin 3-O-gallate (5), (-)-epigallocatechin (6), (-)-epigallocatechin 3-O-gallate (7), (+)-gallocatechin-(4alpha-->8')-epigallocatechin (8), and (-)-epigallocatechin-(2beta-->O-->7', 4beta-->8')-epicatechin 3'-O-gallate (9) were isolated from the tea plant Camellia sinensis L. (+)-Epigallocatechin-(2beta-->O-->7, 4beta-->8')-epicatechin (10) was prepared by hydrolyzing 9. The polyphenols, as well as commercially available pyrogallol (1), methyl gallate (2), (+)-catechin (3), (-)-epicatechin (4), and the flavonol myricetin (11), produced O(2(-)) in descending order 1, 6 asymptotically equal to11 asymptotically equal to8, 7, 10, 2 asymptotically equal to9, 5 asymptotically equal to4. In the polyphenols with the pyrogallol-type B-ring and/or galloyl group, electron-withdrawing substituents (carbonyl and ketal carbons) and/or intramolecular hydrogen bonding constituted structural characteristics against the autoxidation reaction. The O(2(-))-productive activity partially counteracted O(2(-))-scavenging activity. However, such structural characteristics appeared to enhance the scavenging activity, accordingly the polyphenols in effect served as O(2(-))-scavengers in descending order 9 asymptotically equal to7, 2, 11, 8, 10, 3 asymptotically equal to4. On the other hand, 6, having no such structural characteristic, acted as a O(2(-))-generator, as well as 1. Further assessments covering tannins (e.g., A-type proanthocyanidin dimer 9) are needed to identify which green tea polyphenols are the most desirable chemopreventive agents.

[Modifications of the superoxide anion level in breast milk by the intake of flavonoids and carotenoids].

PubMed

Marchesino, Mariana A; Cortez, Mariela V; Albrecht, Claudia; Aballay, Laura R; Soria, Elio A

2017-01-01

To associate the intake of flavonoids and carotenoids with the breast milk level of superoxide anion, as an oxidative stress marker. 100 women from Cordoba (Argentina), who breastfed within the first postpartum 6 months, were studied during the 2013-2015 period, by evaluating their sanitary data, food intake and anion level in milk with multiple logistic regression. The intake of flavonoids, provitamin A carotenoids and non-provitamin carotenoids was 72 (61) mg/d, 1813 (1 657) µg/d y 5427 (3 664) µg/d, respectively. The anion was associated with the intake of flavanols (OR=1.081; CI95 1.001-1.167) y flavanones (OR=1.025; CI95 1.001-1.048). This effect was not seen with other flavonoids and carotenoids. Intake of flavanols and flavanones increases milk oxidation risk, which is relevant to develop diet recommendations.

Diabetes-Induced Superoxide Anion and Breakdown of the Blood-Retinal Barrier: Role of the VEGF/uPAR Pathway

PubMed Central

El-Remessy, Azza B.; Franklin, Telina; Ghaley, Nagla; Yang, Jinling; Brands, Michael W.; Caldwell, Ruth B.; Behzadian, Mohamed Ali

2013-01-01

Diabetes-induced breakdown of the blood-retinal barrier (BRB) has been linked to hyperglycemia-induced expression of vascular endothelial growth factor (VEGF) and is likely mediated by an increase in oxidative stress. We have shown that VEGF increases permeability of retinal endothelial cells (REC) by inducing expression of urokinase plasminogen activator receptor (uPAR). The purpose of this study was to define the role of superoxide anion in VEGF/uPAR expression and BRB breakdown in diabetes. Studies were performed in streptozotocin diabetic rats and mice and high glucose (HG) treated REC. The superoxide dismutase (SOD) mimetic tempol blocked diabetes-induced permeability and uPAR expression in rats and the cell permeable SOD inhibited HG-induced expression of uPAR and VEGF in REC. Inhibiting VEGFR blocked HG-induced expression of VEGF and uPAR and GSK-3β phosphorylation in REC. HG caused β-catenin translocation from the plasma membrane into the cytosol and nucleus. Treatment with HG-conditioned media increased REC paracellular permeability that was blocked by anti-uPA or anti-uPAR antibodies. Moreover, deletion of uPAR blocked diabetes-induced BRB breakdown and activation of MMP-9 in mice. Together, these data indicate that diabetes-induced oxidative stress triggers BRB breakdown by a mechanism involving uPAR expression through VEGF-induced activation of the GSK3β/β-catenin signaling pathway. PMID:23951261

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

DOE PAGES

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

2014-12-05

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

Superoxide anions produced by Streptococcus pyogenes group A-stimulated keratinocytes are responsible for cellular necrosis and bacterial growth inhibition.

PubMed

Regnier, Elodie; Grange, Philippe A; Ollagnier, Guillaume; Crickx, Etienne; Elie, Laetitia; Chouzenoux, Sandrine; Weill, Bernard; Plainvert, Céline; Poyart, Claire; Batteux, Frédéric; Dupin, Nicolas

2016-02-01

Gram-positive Streptococcus pyogenes (group A Streptococcus or GAS) is a major skin pathogen and interacts with keratinocytes in cutaneous tissues. GAS can cause diverse suppurative and inflammatory infections, such as cellulitis, a common acute bacterial dermo-hypodermitis with a high morbidity. Bacterial isolation yields from the lesions are low despite the strong local inflammation observed, raising numerous questions about the pathogenesis of the infection. Using an in vitro model of GAS-infected keratinocytes, we show that the major ROS produced is the superoxide anion ([Formula: see text]), and that its production is time- and dose-dependent. Using specific modulators of ROS production, we show that [Formula: see text] is mainly synthesized by the cytoplasmic NADPH oxidase. Superoxide anion production leads to keratinocyte necrosis but incomplete inhibition of GAS growth, suggesting that GAS may be partially resistant to the oxidative burst. In conclusion, GAS-stimulated keratinocytes are able to develop an innate immune response based on the production of ROS. This local immune response limits GAS development and induces keratinocyte cell death, resulting in the skin lesions observed in patients with cellulitis. © The Author(s) 2015.

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

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

Orona, N.S.; Tasat, D.R., E-mail: deborah.tasat@unsam.edu.ar; School of Dentistry, University of Buenos Aires, M. T. de Alvear 2142

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{submore » 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

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

PubMed

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

2002-01-01

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

Differentiation by hydroquinone of relaxations induced by exogenous and endogenous nitrates in non-vascular smooth muscle: role of superoxide anions.

PubMed Central

Hobbs, A. J.; Tucker, J. F.; Gibson, A.

1991-01-01

1. The influence of hydroquinone on relaxations induced by nitric oxide (NO), nitrovasodilator drugs, and non-adrenergic, non-cholinergic (NANC) field stimulation has been investigated in three tissues in which endogenous nitrates have been implicated in the NANC response; the mechanism of action of hydroquinone was also studied. 2. In mouse anococcygeus, hydroquinone (10-100 microM) produced a concentration-dependent inhibition of relaxations induced by 15 microM NO. Hydroquinone, 100 microM, which reduced responses to NO by 85%, had no effect on relaxations induced by NANC field stimulation (10 Hz; 20s trains), hydroxylamine (10 microM), sodium nitroprusside (1 microM) or sodium azide (20 microM). 3. In guinea-pig trachea, 100 microM hydroquinone reduced relaxations to 150 microM NO by 75%, but had no effect on those to NANC stimulation (10 Hz; 30 s trains) or sodium azide (5 microM). 4. In rat gastric fundus, 100 microM hydroquinone reduced relaxations to 1 microM NO by 85%, but had no effect on those to NANC stimulation (0.5 Hz; 15 s trains) or sodium azide (2 microM). 5. Superoxide dismutase (SOD; 50 u ml-1) had no effect on relaxations of the mouse anococcygeus in response to 15 microM NO or 10 Hz NANC stimulation. Further, the inhibition of responses to NO by hydroquinone was unaffected in the presence of SOD. 6. Hydroquinone (10-100 microM) failed to generate superoxide anions, as detected by a chemiluminescent assay. However, 100 microM hydroquinone, like SOD (50 u ml-1), produced almost complete inhibition of superoxide anion chemiluminescence induced by xanthine (500 microM): xanthine oxidase (0.07 u ml-1). 7. It is concluded that, in our system, hydroquinone inhibits NO by acting as a free radical scavenger rather than by generating superoxide anions. The ability of hydroquinone to block relaxations to NO, but not NANC stimulation, may suggest that the endogenous nitrate substance released by these NANC nerves may not be free NO, but may be an NO

Ultrasensitive detection of superoxide anion released from living cells using a porous Pt-Pd decorated enzymatic sensor.

PubMed

Zhu, Xiang; Liu, Tingting; Zhao, Hongli; Shi, Libo; Li, Xiaoqing; Lan, Minbo

2016-05-15

Considering the critical roles of superoxide anion (O2(∙-)) in pathological conditions, it is of great urgency to establish a reliable and durable approach for real-time determination of O2(∙-). In this study, we propose a porous Pt-Pd decorated superoxide dismutase (SOD) sensor for qualitative and quantitative detection O2(∙-). The developed biosensor exhibits a fast, selective and linear amperometric response upon O2(∙-) in the concentration scope of 16 to 1,536 μM (R(2)=0.9941), with a detection limit of 0.13 μM (S/N=3) and a low Michaelis-Menten constant of 1.37 μM which indicating a high enzymatic activity and affinity to O2(∙-). Inspiringly, the proposed sensor possesses an ultrahigh sensitivity of 1270 μA mM(-1)cm(-2). In addition, SOD/porous Pt-Pd sensor exhibits excellent anti-interference property, reproducibility and long-term storage stability. Beyond our expectation, the trace level of O2(∙-) released from living cells has also been successfully captured. These satisfactory results are mainly ascribed to (1) the porous interface with larger surface area and more active sites to provide a biocompatible environment for SOD (2) the specific biocatalysis of SOD towards O2(∙-) and (3) porous Pt-Pd nanomaterials fastening the electron transfer. The superior electrochemical performance makes SOD/porous Pt-Pd sensor a promising candidate for monitoring the dynamic changes of O2(∙-)in vivo. Copyright © 2015 Elsevier B.V. All rights reserved.

Compartmentalized oxidative stress in dopaminergic cell death induced by pesticides and complex I inhibitors: Distinct roles of superoxide anion and superoxide dismutases

PubMed Central

Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Pickett, Chillian; Sumin, Li; Jones, Jocelyn; Chen, Han; Webb, Brian; Choi, Jae; Zhou, You; Zimmerman, Matthew C.; Franco, Rodrigo

2013-01-01

The loss of dopaminergic neurons induced by the parkinsonian toxins paraquat, rotenone and 1-methyl-4-phenylpyridinium (MPP+) is associated with oxidative stress. However, controversial reports exist regarding the source/compartmentalization of reactive oxygen species (ROS) generation and its exact role in cell death. We aimed to determine in detail the role of superoxide anion (O2•−), oxidative stress and their subcellular compartmentalization in dopaminergic cell death induced by parkinsonian toxins. Oxidative stress and ROS formation was determined in the cytosol, intermembrane (IMS) and mitochondrial matrix compartments, using dihydroethidine derivatives, the redox sensor roGFP, as well as electron paramagnetic resonance spectroscopy. Paraquat induced an increase in ROS and oxidative stress in both the cytosol and mitochondrial matrix prior to cell death. MPP+ and rotenone primarily induced an increase in ROS and oxidative stress in the mitochondrial matrix. No oxidative stress was detected at the level of the IMS. In contrast to previous studies, overexpression of manganese superoxide dismutase (MnSOD) or copper/zinc SOD (CuZnSOD) had no effect on ROS steady state levels, lipid peroxidation, loss of mitochondrial membrane potential (ΔΨm) and dopaminergic cell death induced by MPP+ or rotenone. In contrast, paraquat-induced oxidative stress and cell death were selectively reduced by MnSOD overexpression, but not by CuZnSOD or manganese-porphyrins. However, MnSOD also failed to prevent ΔΨm loss. Finally, paraquat, but not MPP+ or rotenone, induced the transcriptional activation the redox-sensitive antioxidant response elements (ARE) and nuclear factor kappa-B (NF-κB). These results demonstrate a selective role of mitochondrial O2•− in dopaminergic cell death induced by paraquat, and show that toxicity induced by the complex I inhibitors rotenone and MPP+ does not depend directly on mitochondrial O2•− formation. PMID:23602909

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

PubMed

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

2013-07-01

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

Stochastic modelling suggests that an elevated superoxide anion - hydrogen peroxide ratio can drive extravascular phagocyte transmigration by lamellipodium formation.

PubMed

Kundu, Siddhartha

2016-10-21

Chemotaxis, integrates diverse intra- and inter-cellular molecular processes into a purposeful patho-physiological response; the operatic rules of which, remain speculative. Here, I surmise, that superoxide anion induced directional motility, in a responding cell, results from a quasi pathway between the stimulus, surrounding interstitium, and its biochemical repertoire. The epochal event in the mounting of an inflammatory response, is the extravascular transmigration of a phagocyte competent cell towards the site of injury, secondary to the development of a lamellipodium. This stochastic-to-markovian process conversion, is initiated by the cytosolic-ROS of the damaged cell, but is maintained by the inverse association of a de novo generated pool of self-sustaining superoxide anions and sub-critical hydrogen peroxide levels. Whilst, the exponential rise of O2(.-) is secondary to the focal accumulation of higher order lipid raft-Rac1/2-actin oligomers; O2(.-) mediated inactivation and redistribution of ECSOD, accounts for the minimal concentration of H2O2 that the phagocyte experiences. The net result of this reciprocal association between ROS/ RNS members, is the prolonged perturbation and remodeling of the cytoskeleton and plasma membrane, a prelude to chemotactic migration. The manuscript also describes the significance of stochastic modeling, in the testing of plausible molecular hypotheses of observable phenomena in complex biological systems. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Phylogeny and Active Site Design of Eukaryotic Copper-only Superoxide Dismutases*

PubMed Central

Peterson, Ryan L.; Galaleldeen, Ahmad; Villarreal, Johanna; Taylor, Alexander B.; Cabelli, Diane E.; Hart, P. John; Culotta, Valeria C.

2016-01-01

In eukaryotes the bimetallic Cu/Zn superoxide dismutase (SOD) enzymes play important roles in the biology of reactive oxygen species by disproportionating superoxide anion. Recently, we reported that the fungal pathogen Candida albicans expresses a novel copper-only SOD, known as SOD5, that lacks the zinc cofactor and electrostatic loop (ESL) domain of Cu/Zn-SODs for substrate guidance. Despite these abnormalities, C. albicans SOD5 can disproportionate superoxide at rates limited only by diffusion. Here we demonstrate that this curious copper-only SOD occurs throughout the fungal kingdom as well as in phylogenetically distant oomycetes or “pseudofungi” species. It is the only form of extracellular SOD in fungi and oomycetes, in stark contrast to the extracellular Cu/Zn-SODs of plants and animals. Through structural biology and biochemical approaches we demonstrate that these copper-only SODs have evolved with a specialized active site consisting of two highly conserved residues equivalent to SOD5 Glu-110 and Asp-113. The equivalent positions are zinc binding ligands in Cu/Zn-SODs and have evolved in copper-only SODs to control catalysis and copper binding in lieu of zinc and the ESL. Similar to the zinc ion in Cu/Zn-SODs, SOD5 Glu-110 helps orient a key copper-coordinating histidine and extends the pH range of enzyme catalysis. SOD5 Asp-113 connects to the active site in a manner similar to that of the ESL in Cu/Zn-SODs and assists in copper cofactor binding. Copper-only SODs are virulence factors for certain fungal pathogens; thus this unique active site may be a target for future anti-fungal strategies. PMID:27535222

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

NASA Astrophysics Data System (ADS)

Joshi, Ravi

2017-10-01

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

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

EPA Science Inventory

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

The Phylogeny and Active Site Design of Eukaryotic Copper-only Superoxide Dismutases

DOE PAGES

Peterson, Ryan L.; Galaleldeen, Ahmad; Villarreal, Johanna; ...

2016-08-17

In eukaryotes the bimetallic Cu/Zn superoxide dismutase (SOD) enzymes play important roles in the biology of reactive oxygen species by disproportionating superoxide anion. We reported that the fungal pathogen Candida albicans expresses a novel copper-only SOD, known as SOD5, that lacks the zinc cofactor and electrostatic loop (ESL) domain of Cu/Zn-SODs for substrate guidance. In spite of these abnormalities, C. albicans SOD5 can disproportionate superoxide at rates limited only by diffusion. Here we demonstrate that this curious copper-only SOD occurs throughout the fungal kingdom as well as in phylogenetically distant oomycetes or “pseudofungi” species. It is the only form ofmore » extracellular SOD in fungi and oomycetes, in stark contrast to the extracellular Cu/Zn-SODs of plants and animals. Through structural biology and biochemical approaches we demonstrate that these copper-only SODs have evolved with a specialized active site consisting of two highly conserved residues equivalent to SOD5 Glu-110 and Asp-113. The equivalent positions are zinc binding ligands in Cu/Zn-SODs and have evolved in copper-only SODs to control catalysis and copper binding in lieu of zinc and the ESL. Similar to the zinc ion in Cu/Zn-SODs, SOD5 Glu-110 helps orient a key copper-coordinating histidine and extends the pH range of enzyme catalysis. Furthermore, SOD5 Asp-113 connects to the active site in a manner similar to that of the ESL in Cu/Zn-SODs and assists in copper cofactor binding. Copper-only SODs are virulence factors for certain fungal pathogens; thus this unique active site may be a target for future anti-fungal strategies.« less

Two novel cyanobacterial bioluminescent whole-cell bioreporters based on superoxide dismutases MnSod and FeSod to detect superoxide anion.

PubMed

Hurtado-Gallego, J; Martín-Betancor, K; Rodea-Palomares, I; Leganés, F; Rosal, R; Fernández-Piñas, F

2018-06-01

This work describes the construction of two novel self-luminescent bioreporter strains of the cyanobacterium Nostoc sp. PCC 7120 by fusing the promoter region of the sodA and sodB genes (encoding the superoxide dismutases MnSod and FeSod, respectively) to luxCDABE from Photorhabdus luminescens aimed at detecting pollutants that generate reactive oxygen species (ROS), particularly O 2 - . Bioreporters were tested against methyl viologen (MV) as the inducer of superoxide anion (O 2 - ). Both bioreporters were specific for O 2 - and Limits of detection (LODs) and Maximum Permissive Concentrations (MPCs) were calculated: Nostoc sp. PCC 7120 pBG2154 (sodA) had a range of detection from 400 to 1000 pM of MV and for Nostoc sp. PCC 7120 pBG2165 (sodB) the range of detection was from 500 to 1800 pM of MV after 5 h-exposure. To further validate the bioreporters, they were tested with the emerging pollutant Triclosan which induced bioluminescence in both strains. Furthermore, the bioreporters performance was tested in two real environmental samples with different water matrix complexity, spiked with MV. Both bioreporters were induced by O 2 - in these environmental samples. In the case of the river water sample, the amount of bioavailable MV as calculated from the bioreporters output was similar to that nominally added. For the waste water sample, the bioavailable MV concentration detected by the bioreporters was one order of magnitude lower than nominal. These differences could be due to MV complexation with organic matter and/or co-occurring organic contaminants. These results confirm their high sensitivity to O 2 - and their suitability to detect oxidative stress-generating pollutants in fresh-waters. Copyright © 2018 Elsevier Ltd. All rights reserved.

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

PubMed

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

1996-03-01

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

Immobilization of Superoxide Dismutase on Polyelectrolyte-Functionalized Titania Nanosheets.

PubMed

Rouster, Paul; Pavlovic, Marko; Szilagyi, Istvan

2018-02-16

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

Ras activation modulates methylglyoxal-induced mesangial cell apoptosis through superoxide production.

PubMed

Huang, Wei Jan; Tung, Chun Wu; Ho, Cheng; Yang, Jen Tsung; Chen, Min Li; Chang, Pey Jium; Lee, Pei Hsien; Lin, Chun Liang; Wang, Jeng Yi

2007-01-01

While previous studies have demonstrated that diabetic nephropathy is attributable to glucose-derived dicarbonyl compounds, methylglyoxal (MGO)-inducing apoptosis in renal mesangial cells, the molecular mechanism of upper stream redox signaling modulation, has not been fully elucidated. Rat mesangial cells pretreated with or without superoxide dismutase, diphenyloniodium, SB203580, and manumycin A were cultured in methylglyoxal stress-induced apoptosis. Signaling protein expression, flow cytometry, and morphological features of apoptotic cell death were assessed. Methylglyoxal decreased cell viability in mesangial cells. Superoxide mediated methylglyoxal-induced caspase 3 cleavage. Pretreatment with diphenyloniodium, SB203580, and manumycin A reduced methylglyoxal augmentation of superoxide synthesis and caspase-3 activation. Methylglyoxal rapidly enhanced Ras activation and progressively increased cytosolic P38 and nuclear c-Jun activation. Scavenging of superoxide by superoxide dismutase or diphenyloniodium, inhibiting P38 by SB203580, and inhibiting Ras with manumycin A successfully reduced the promoting effect of methylglyoxal on P38 and c-Jun phosphorylation (activation). Furthermore, pretreatment with superoxide dismutase, diphenyloniodium, SB203580, and manumycin A significantly attenuated methylglyoxal induction of apoptosis on the basis of Annexin-V assay and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end-labelling (TUNEL) staining. This study has shown that methylglyoxal increased Ras modulation of superoxide-mediated P38 activation and c-Jun activation, which resulted in increased apoptosis.

Synthesis of calcium superoxide

NASA Technical Reports Server (NTRS)

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

1972-01-01

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

Curcumin causes superoxide anion production and p53-independent apoptosis in human colon cancer cells.

PubMed

Watson, Jane L; Hill, Richard; Yaffe, Paul B; Greenshields, Anna; Walsh, Mark; Lee, Patrick W; Giacomantonio, Carman A; Hoskin, David W

2010-11-01

Curcumin from the rhizome of theCurcuma longa plant has chemopreventative activity and inhibits the growth of neoplastic cells. Since p53 has been suggested to be important for anticancer activity by curcumin, we investigated curcumin-induced cytotoxicity in cultures of p53(+/+) and p53(-/-) HCT-116 colon cancer cells, as well as mutant p53 HT-29 colon cancer cells. Curcumin killed wild-type p53 HCT-116 cells and mutant p53 HT-29 cells in a dose- and time-dependent manner. In addition, curcumin-treated p53(+/+) HCT-116 cells and mutant p53 HT-29 cells showed upregulation of total and activated p53, as well as increased expression of p53-regulated p21, PUMA (p53 upregulated modulator of apoptosis), and Bax; however, an equivalent cytotoxic effect by curcumin was observed in p53(+/+) and p53(-/-) HCT-116 cells, demonstrating that curcumin-induced cytotoxicity was independent of p53 status. Similar results were obtained when the cytotoxic effect of curcumin was assessed in wild-type p53 HCT-116 cells after siRNA-mediated p53 knockdown. Chromatin condensation, poly (ADP-ribose) polymerase-1 cleavage and reduced pro-caspase-3 levels in curcumin-treated p53(+/+) and p53(-/-) HCT-116 cells suggested that curcumin caused apoptosis. In addition, exposure to curcumin resulted in superoxide anion production and phosphorylation of oxidative stress proteins in p53(+/+) and p53(-/-) HCT-116 cells. Collectively, our results indicate that, despite p53 upregulation and activation, curcumin-induced apoptosis in colon cancer cells was independent of p53 status and involved oxidative stress. Curcumin may therefore have therapeutic potential in the management of colon cancer, especially in tumorsthatare resistant to conventional chemotherapydue todefects inp53 expression or function. 2010 Elsevier Ireland Ltd. All rights reserved.

Recent trends in electrochemical biosensors of superoxide dismutases.

PubMed

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

2018-09-30

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

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

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

Yogi, Alvaro; Callera, Glaucia E.; Mecawi, André S.

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 inducedmore » 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

OXIDATIVE STRESS ACTIVATES ANION EXCHANGE PROTEIN 2 AND AP-1 IN AIRWAY EPITHELIAL CELLS

EPA Science Inventory

Anion exchange protein 2 (AE2) is a membrane-bound protein that mediates chloride-bicarbonate exchange. In addition to regulating intracellular pH and cell volume, AE2 exports superoxide (O.) to the extracellular matrix in an HCO-dependent process. Given this ability to export O....

BPA-toxicity via superoxide anion overload and a deficit in β-catenin signaling in human bone mesenchymal stem cells.

PubMed

Leem, Yea-Hyun; Oh, Seikwan; Kang, Hong-Je; Kim, Jung-Hwa; Yoon, Juno; Chang, Jae-Suk

2017-01-01

Bisphenol A (BPA), used in the manufacture of products based on polycarbonate plastics and epoxy resins, is well known as an endocrine-disrupting monomer. In the current study, BPA increased cytotoxicity in hBMSCs in a dose- and time-dependent manner, concomitantly with increased lipid peroxidation. Increased cell death in BPA-treated cells was markedly blocked by pretreatment with the superoxide dismutase mimetic MnTBAP and MnTMPyP, but not by catalase, glutathione, the glutathione peroxidase mimetic ebselen, the NOS inhibitor NAME, or the xanthine oxidase inhibitor allopurinol. Furthermore, the decline in nuclear β-catenin and cyclin D1 levels in hBMSCs exposed to BPA was reversed by MnTBAP treatment. Finally, treatment of hBMSCs with the GSK3β inhibitor LiCl 2 increased nuclear β-catenin levels and significantly attenuated cytotoxicity compared with BPA treatment. Our current results in hBMSCs exposed to BPA suggest that BPA causes a disturbance in β-catenin signaling via a superoxide anion overload. © 2016 The Authors Environmental Toxicology Published by Wiley Periodicals, Inc. Environ Toxicol 32: 344-352, 2017. © 2016 The Authors Environmental Toxicology Published by Wiley Periodicals, Inc.

Role of superoxide radical anion in the mechanism of apoB100 degradation induced by DHA in hepatic cells

PubMed Central

Andreo, Ursula; Elkind, Josh; Blachford, Courtney; Cederbaum, Arthur I.; Fisher, Edward A.

2011-01-01

VLDL is produced by the liver. Its major protein is apoB100. Docosahexaenoic acid (DHA), a dietary polyunsaturated fatty acid (PUFA), reduces VLDL levels and is used therapeutically for hypertriglyceridemia. In model systems, DHA lowers VLDL secretion by inducing presecretory apoB100 degradation, a process dependent on PUFA-derived lipid peroxides. We hypothesized that superoxide (SO) was a major participant in DHA-induced apoB100 degradation, given its promotion of lipid peroxidation. SO levels in a model of VLDL metabolism, rat hepatoma McArdle cells, were either decreased by a mimetic of superoxide dismutase 1 (SOD1) or by overexpressing SOD1 or increased by SOD1 siRNA. ApoB100 recovery was assessed by immunoprecipitation, SO by 2-hydroxyethidine, and lipid peroxides by thiobarbituric acid reactive substances. The SOD1 mimetic or SOD1 overexpression reduced SO and inhibited apoB100 degradation in DHA-treated cells by up to 100%. Surprisingly, silencing SOD1 did not increase DHA-induced degradation, although levels of SO were higher (+44%); those of lipid peroxides were similar, and their reduction by α-tocopherol decreased degradation by 50%. SO is required for lipid peroxidation in DHA-induced apoB100 degradation, but it is the peroxide level that has a tighter relationship to the level of degradation and the regulation of VLDL production.—Andreo, U., Elkind, J., Blachford, C., Cederbaum, A. I., Fisher, E. A. Role of superoxide radical anion in the mechanism of apoB100 degradation induced by DHA in hepatic cells. PMID:21757500

Study of the simulated sunlight photolysis mechanism of ketoprofen: the role of superoxide anion radicals, transformation byproducts, and ecotoxicity assessment.

PubMed

Wang, Yingfei; Deng, Wen; Wang, Fengliang; Su, Yuehan; Feng, Yiping; Chen, Ping; Ma, Jingshuai; Su, Haiying; Yao, Kun; Liu, Yang; Lv, Wenying; Liu, Guoguang

2017-09-20

The aim of this study was to investigate the photolysis mechanism of ketoprofen (KET) under simulated sunlight. The results demonstrated that the photolysis of KET aligned well with pseudo first-order kinetics. Radical scavenging experiments and dissolved oxygen experiments revealed that the superoxide anion radical (O 2 ˙ - ) played a primary role in the photolytic process in pure water. Bicarbonate slightly increased the photodegradation of KET through generating carbonate radicals, while DOM inhibited the photolysis via both attenuating light and competing radicals. Moreover, Zhujiang river water inhibited KET phototransformation. Potential KET degradation pathways were proposed based on the identification of products using LC/MS/MS and GC/MS techniques. The theoretical prediction of reaction sites was derived from Frontier Electron Densities (FEDs), which primarily involved the KET decarboxylation reaction. The ecotoxicity of the treated solutions was evaluated by employing Daphnia magna and V. fischeri as biological indicators. Ecotoxicity was also hypothetically predicted through the "ecological structure-activity relationship" (ECOSAR) program, which revealed that toxic products might be generated during the photolysis process.

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

USDA-ARS?s Scientific Manuscript database

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

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

PubMed

Okamoto, Yuichi; Aoki, Shigeji; Mataga, Izumi

2004-07-01

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

BPA‐toxicity via superoxide anion overload and a deficit in β‐catenin signaling in human bone mesenchymal stem cells

PubMed Central

Oh, Seikwan; Kang, Hong‐Je; Kim, Jung‐Hwa; Yoon, Juno

2016-01-01

ABSTRACT Bisphenol A (BPA), used in the manufacture of products based on polycarbonate plastics and epoxy resins, is well known as an endocrine‐disrupting monomer. In the current study, BPA increased cytotoxicity in hBMSCs in a dose‐ and time‐dependent manner, concomitantly with increased lipid peroxidation. Increased cell death in BPA‐treated cells was markedly blocked by pretreatment with the superoxide dismutase mimetic MnTBAP and MnTMPyP, but not by catalase, glutathione, the glutathione peroxidase mimetic ebselen, the NOS inhibitor NAME, or the xanthine oxidase inhibitor allopurinol. Furthermore, the decline in nuclear β‐catenin and cyclin D1 levels in hBMSCs exposed to BPA was reversed by MnTBAP treatment. Finally, treatment of hBMSCs with the GSK3β inhibitor LiCl2 increased nuclear β‐catenin levels and significantly attenuated cytotoxicity compared with BPA treatment. Our current results in hBMSCs exposed to BPA suggest that BPA causes a disturbance in β‐catenin signaling via a superoxide anion overload. © 2016 The Authors Environmental Toxicology Published by Wiley Periodicals, Inc. Environ Toxicol 32: 344–352, 2017. PMID:26822619

Expression and characterization of recombinant bifunctional enzymes with glutathione peroxidase and superoxide dismutase activities.

PubMed

Guan, Tuchen; Song, Jian; Wang, Yanan; Guo, Liying; Yuan, Lin; Zhao, Yingding; Gao, Yuan; Lin, Liangru; Wang, Yali; Wei, Jingyan

2017-09-01

To balance the production and decomposition of reactive oxygen species, living organisms have generated antioxidant enzymes and non-enzymatic antioxidant defense systems. Glutathione peroxidase (GPx) and superoxide dismutase (SOD) are two important antioxidant enzymes. Apart from their catalytic functions, they protect each other, resulting in more efficient removal of reactive oxygen species, protection of cells against injury, and maintenance of the normal metabolism of reactive oxygen species. SOD catalyzes the dismutation of the superoxide anion (O 2 •- ) to oxygen (O 2 ) and hydrogen peroxide (H 2 O 2 ). H 2 O 2 is then detoxified to water by GPx. In this study, human GPx1 Ser and the Alvinella pompejana SOD (ApSOD) gene were used to design and generate several recombinant proteins with both GPx and SOD activities by combining traditional fusion protein technology, a cysteine auxotrophic expression system, and a single protein production (SPP) system. Among the fusion proteins, Se-hGPx1 Ser -L-ApSOD exhibited the highest SOD and GPx activities. Additional research was conducted to better understand the properties of Se-hGPx1 Ser -L-ApSOD. The synergism of Se-hGPx1 Ser -L-ApSOD was evaluated by using an in vitro model. This research may facilitate future studies on the cooperation and catalytic mechanisms of GPx and SOD. We believe that the bifunctional enzyme has potential applications as a potent antioxidant. Copyright © 2017 Elsevier Inc. All rights reserved.

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

PubMed

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

2012-04-01

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

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

PubMed

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.

The role of mitochondrial superoxide anion (O2(-)) on physiological aging in C57BL/6J mice.

PubMed

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.

Superoxide anion radical-triggered Ca2+ release from cardiac sarcoplasmic reticulum through ryanodine receptor Ca2+ channel.

PubMed

Kawakami, M; Okabe, E

1998-03-01

The ryanodine receptor Ca2+ channel (RyRC) constitutes the Ca2+-release pathway in sarcoplasmic reticulum (SR) of cardiac muscle. A direct mechanical and a Ca2+-triggered mechanism (Ca2+-induced Ca2+ release) have been proposed to explain the in situ activation of Ca2+ release in cardiac muscle. A variety of chemical oxidants have been shown to activate RyRC; however, the role of modification induced by oxygen-derived free radicals in pathological states of the muscle remains to be elucidated. It has been hypothesized that oxygen-derived free radicals initiate Ca2+-mediated functional changes in or damage to cardiac muscle by acting on the SR and promoting an increase in Ca2+ release. We confirmed that superoxide anion radical (O2-) generated from hypoxanthine-xanthine oxidase reaction decreases calmodulin content and increases 45Ca2+ efflux from the heavy fraction of canine cardiac SR vesicles; hypoxanthine-xanthine oxidase also decreases Ca2+ free within the intravesicular space of the SR with no effect on Ca2+-ATPase activity. Current fluctuations through single Ca2+-release channels have been monitored after incorporation into planar phospholipid bilayers. We demonstrate that activation of the channel by O2- is dependent of the presence of calmodulin and identified calmodulin as a functional mediator of O2--triggered Ca2+ release through the RyRC. For the first time, we show that O2- stimulates Ca2+ release from heavy SR vesicles and suggest the importance of accessory proteins such as calmodulin in modulating the effect of O2-. The decreased calmodulin content induced by oxygen-derived free radicals, especially O2-, is a likely mechanism of accumulation of cytosolic Ca2+ (due to increased Ca2+ release from SR) after reperfusion of the ischemic heart.

2',3-dihydroxy-5-methoxybiphenyl suppresses fMLP-induced superoxide anion production and cathepsin G release by targeting the β-subunit of G-protein in human neutrophils.

PubMed

Liao, Hsiang-Ruei; Chen, Ih-Sheng; Liu, Fu-Chao; Lin, Shinn-Zhi; Tseng, Ching-Ping

2018-06-15

This study investigates the effect and the underlying mechanism of 2',3-dihydroxy-5-methoxybiphenyl (RIR-2), a lignan extracted from the roots of Rhaphiolepis indica (L.) Lindl. ex Ker var. tashiroi Hayata ex Matsum. & Hayata (Rosaceae), on N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-induced respiratory burst and cathepsin G in human neutrophils. Signaling pathways regulated by RIR-2 which modulated fMLP-induced respiratory burst were evaluated by an interaction between β subunit of G-protein (Gβ) with downstream signaling induced by fMLP and by immunoblotting analysis of the downstream targets of Gβ-protein. RIR-2 inhibited fMLP-induced superoxide anion production (IC 50 :2.57 ± 0.22 μM), cathepsin G release (IC 50 :18.72 ± 3.76 μM) and migration in a concentration dependent manner. RIR-2 specifically suppresses fMLP-induced Src family kinases phosphorylation by inhibiting the interaction between Gβ-protein with Src kinases without inhibiting Src kinases activities, therefore, RIR-2 attenuated the downstream targets of Src kinase, such as phosphorylation of Raf/ERK, AKT, P38, PLCγ2, PKC and translocation Tec, p47 ph ° x and P40 ph ° x from the cytosol to the inner leaflet of the plasma membrane. Furthermore, RIR-2 attenuated fMLP-induced intracellular calcium mobilization by inhibiting the interaction between Gβ-protein with PLCβ2. RIR-2 was not a competitive or allosteric antagonist of fMLP. On the contrary, phorbol 12-myristate 13-acetate (PMA)-induced phosphorylation of Src, AKT, P38, PKC and membrane localization of p47 ph ° x and P40 ph ° x remained unaffected. RIR-2 specifically modulates fMLP-mediated neutrophil superoxide anion production and cathepsin G release by inhibiting the interaction between Gβ-protein with downstream signaling which subsequently interferes with the activation of intracellular calcium, PLCγ2, AKT, p38, PKC, ERK, p47 ph ° x and p40 phox . Copyright © 2018 Elsevier B.V. All rights reserved.

Ratiometric fluorescence detection of superoxide anion based on AuNPs-BSA@Tb/GMP nanoscale coordination polymers.

PubMed

Liu, Nan; Hao, Juan; Cai, Keying; Zeng, Mulan; Huang, Zhenzhong; Chen, Lili; Peng, Bingxian; Li, Ping; Wang, Li; Song, Yonghai

2018-02-01

A novel ratiometric fluorescence nanosensor for superoxide anion (O 2 •- ) detection was designed with gold nanoparticles-bovine serum albumin (AuNPs-BSA)@terbium/guanosine monophosphate disodium (Tb/GMP) nanoscale coordination polymers (NCPs) (AuNPs-BSA@Tb/GMP NCPs). The abundant hydroxyl and amino groups of AuNPs-BSA acted as binding points for the self-assembly of Tb 3+ and GMP to form core-shell AuNPs-BSA@Tb/GMP NCP nanosensors. The obtained probe exhibited the characteristic fluorescence emission of both AuNPs-BSA and Tb/GMP NCPs. The AuNPs-BSA not only acted as a template to accelerate the growth of Tb/GMP NCPs, but also could be used as the reference fluorescence for the detection of O 2 •- . The resulting AuNPs-BSA@Tb/GMP NCP ratiometric fluorescence nanosensor for the detection of O 2 •- demonstrated high sensitivity and selectivity with a wide linear response range (14 nM-10 μM) and a low detection limit (4.7 nM). Copyright © 2017 John Wiley & Sons, Ltd.

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

PubMed

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

2014-07-14

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

Activation of CuZn superoxide dismutases from Caenorhabditis elegans does not require the copper chaperone CCS.

PubMed

Jensen, Laran T; Culotta, Valeria Cizewski

2005-12-16

Reactive oxygen species are produced as the direct result of aerobic metabolism and can cause damage to DNA, proteins, and lipids. A principal defense against reactive oxygen species involves the superoxide dismutases (SOD) that act to detoxify superoxide anions. Activation of CuZn-SODs in eukaryotic cells occurs post-translationally and is generally dependent on the copper chaperone for SOD1 (CCS), which inserts the catalytic copper cofactor and catalyzes the oxidation of a conserved disulfide bond that is essential for activity. In contrast to other eukaryotes, the nematode Caenorhabditis elegans does not contain an obvious CCS homologue, and we have found that the C. elegans intracellular CuZn-SODs (wSOD-1 and wSOD-5) are not dependent on CCS for activation when expressed in Saccharomyces cerevisiae. CCS-independent activation of CuZn-SODs is not unique to C. elegans; however, this is the first organism identified that appears to exclusively use this alternative pathway. As was found for mammalian SOD1, wSOD-1 exhibits a requirement for reduced glutathione in CCS-independent activation. Unexpectedly, wSOD-1 was inactive even in the presence of CCS when glutathione was depleted. Our investigation of the cysteine residues that form the disulfide bond in wSOD-1 suggests that the ability of wSODs to readily form this disulfide bond may be the key to obtaining high levels of activation through the CCS-independent pathway. Overall, these studies demonstrate that the CuZn-SODs of C. elegans have uniquely evolved to acquire copper without the copper chaperone and this may reflect the lifestyle of this organism.

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

NASA Astrophysics Data System (ADS)

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

1993-09-01

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

Antioxidative capacity and enzyme activity in Haematococcus pluvialis cells exposed to superoxide free radicals

NASA Astrophysics Data System (ADS)

Liu, Jianguo; Zhang, Xiaoli; Sun, Yanhong; Lin, Wei

2010-01-01

The antioxidative capacity of astaxanthin and enzyme activity of reactive oxygen eliminating enzymes such as superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and ascorbate peroxidase (APX) were studied in three cell types of Haematococcus pluvialis exposed to high concentrations of a superoxide anion radical (O{2/-}). The results show that defensive enzymes and astaxanthin-related mechanisms were both active in H. pluvialis during exposure to reactive oxygen species (ROS) such as O{2/-}. Astaxanthin reacted with ROS much faster than did the protective enzymes, and had the strongest antioxidative capacity to protect against lipid peroxidation. The defensive mechanisms varied significantly between the three cell types and were related to the level of astaxanthin that had accumulated in those cells. Astaxanthin-enriched red cells had the strongest antioxidative capacity, followed by brown cells, and astaxanthin-deficient green cells. Although there was no significant increase in expression of protective enzymes, the malondialdehyde (MDA) content in red cells was sustained at a low level because of the antioxidative effect of astaxanthin, which quenched O{2/-} before the protective enzymes could act. In green cells, astaxanthin is very low or absent; therefore, scavenging of ROS is inevitably reliant on antioxidative enzymes. Accordingly, in green cells, these enzymes play the leading role in scavenging ROS, and the expression of these enzymes is rapidly increased to reduce excessive ROS. However, because ROS were constantly increased in this study, the enhance enzyme activity in the green cells was not able to repair the ROS damage, leading to elevated MDA content. Of the four defensive enzymes measured in astaxanthin-deficient green cells, SOD eliminates O{2/-}, POD eliminates H2O2, which is a by-product of SOD activity, and APX and CAT are then initiated to scavenge excessive ROS.

The impact of the lacto-ovo vegetarian diet on the erythrocyte superoxide dismutase activity: a study in the Romanian population.

PubMed

Boancă, M M; Colosi, H A; Crăciun, E C

2014-02-01

Recent studies have shown that vitamin B12 scavenges superoxide anion as effectively as superoxide dismutase (SOD), and has a key role in the defense against oxidative stress. The status of vitamin B12 is suboptimal in a substantial number of vegans and even vegetarians. We therefore evaluated in lacto-ovo vegetarians (LOVs) who did not take vitamin B12 supplements the impact of the duration of this diet on the vitamin B12 status, the erythrocyte SOD activity and the serum malondialdehyde (MDA) concentration. The study group included 38 non-vegetarians and 48 LOVs divided, according to the duration of this diet, into two subgroups: LOV1 (2-10 years) and LOV2 (11-29 years). The erythrocyte SOD activity and the serum concentrations of vitamin B12 and MDA were assayed. In LOVs, the mean serum vitamin B12 concentration, the erythrocyte SOD activity and the mean serum MDA concentration were statistically significantly lower that in non-vegetarians. No significant association between the serum vitamin B12 and MDA concentrations and the duration of the LOV diet were observed. A significant inverse linear correlation between SOD activity and the duration of adherence to LOV diet was observed in LOVs. The duration of LOV diet has impact only on SOD activity. Further researches, both in vitro and in vivo, are necessary to understand the underlying molecular mechanism.

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

PubMed

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

2008-03-06

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

Extracellular Superoxide Dismutase Deficiency Exacerbates Pressure Overload–Induced Left Ventricular Hypertrophy and Dysfunction

PubMed Central

Lu, Zhongbing; Xu, Xin; Hu, Xinli; Zhu, Guangshuo; Zhang, Ping; van Deel, Elza D.; French, Joel P.; Fassett, John T.; Oury, Tim D.; Bache, Robert J.; Chen, Yingjie

2008-01-01

Extracellular superoxide dismutase (SOD) contributes only a small fraction to total SOD activity in the normal heart but is strategically located to scavenge free radicals in the extracellular compartment. To examine the physiological significance of extracellular SOD in the response of the heart to hemodynamic stress, we studied the effect of extracellular SOD deficiency on transverse aortic constriction (TAC)–induced left ventricular remodeling. Under unstressed conditions extracellular SOD deficiency had no effect on myocardial total SOD activity, the ratio of glutathione:glutathione disulfide, nitrotyrosine content, or superoxide anion production but resulted in small but significant increases in myocardial fibrosis and ventricular mass. In response to TAC for 6 weeks, extracellular SOD-deficient mice developed more severe left ventricular hypertrophy (heart weight increased 2.56-fold in extracellular SOD-deficient mice as compared with 1.99-fold in wild-type mice) and pulmonary congestion (lung weight increased 2.92-fold in extracellular SOD-deficient mice as compared with 1.84-fold in wild-type mice). Extracellular SOD-deficient mice also had more ventricular fibrosis, dilation, and a greater reduction of left ventricular fractional shortening and rate of pressure development after TAC. TAC resulted in greater increases of ventricular collagen I, collagen III, matrix metalloproteinase-2, matrix metalloproteinase-9, nitrotyrosine, and superoxide anion production. TAC also resulted in a greater decrease of the ratio of glutathione:glutathione disulfide in extracellular SOD-deficient mice. The finding that extracellular SOD deficiency had minimal impact on myocardial overall SOD activity but exacerbated TAC induced myocardial oxidative stress, hypertrophy, fibrosis, and dysfunction indicates that the distribution of extracellular SOD in the extracellular space is critically important in protecting the heart against pressure overload. PMID:17998475

The Superoxide Reductase from the Early Diverging Eukaryote Giardia Intestinalis

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

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

2011-10-15

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

Influence of local anesthetics upon human polymorphonuclear leukocyte function in vitro. Reduction of lysosomal enzyme release and superoxide anion production

PubMed Central

1977-01-01

Cationic local anesthetics have been reported to influence cellular responses to surface stimuli by interfering with the function of microtubules and microfilaments. Since unimpaired microtubule and microfilament functions are required by human polymorphonuclear leukocytes in order to respond normally to surface stimulation, we have studied effects of the local anesthetic, tetracaine on the function and morphology of these cells in vitro. Tetracaine (0.25--1.0 mM) significantly reduced extracellular release of the lysosomal enzymes, beta-glucuronidase and lysozyme from polymorphonuclear leukocytes exposed to serum-treated zymosan (a particulate stimulus), zymosan- treated serum (a soluble stimulus), and to the surface-active lectin, concanavalin A. Tetracaine also significantly reduced superoixde anion production (superoxide dismutase-inhibitable cytochrome c reduction) by these cells. Tetrancaine was not cytotoxic and its effects could be reversed completely by washing cells once with buffer. Electron microscope examination of tetracaine-treated cells revealed marked alterations of surface membranes. Microtubules and microfilaments appeared normal in "resting" polymorphonuclear leukocytes, but the increase in microtubules normally observed in stimulated cells was not seen after tetracaine treatment. These results suggest that tetracaine interferes with those interactions between immune reactants and the polymorphonuclear leukocyte cell surface which provoke exocytosis and increased oxidative metabolism. PMID:195003

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

PubMed

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

2012-03-01

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

Physical and chemical stability of different formulations with superoxide dismutase.

PubMed

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

2004-10-01

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

Active-oxygen scavenging activity of plant extracts.

PubMed

Masaki, H; Sakaki, S; Atsumi, T; Sakurai, H

1995-01-01

To find antioxidative compounds present in plants, 65 types of plant extract were tested using the neotetrazolium method for evidence of superoxide anion-scavenging effects and 7 plant extracts were selected for further investigation. The activity of active-oxygen scavengers such as superoxide anion radicals, hydroxyl radicals, singlet oxygens and lipid peroxides in the 7 plant extracts (Aeseclus hippocastanum L., Hamamelis virginiana L. Polygonum cuspidatum Sieb., Quercus robur L., Rosemarinous officinalis L., Salvia officinalis L. and Sanguisorba officinalis L.) was examined in detail by both ESR spin-trapping and malondialdehyde generation. Furthermore, the active-oxygen scavenging activity of these plant extracts was evaluated using a murine dermal fibroblast culture system. Both Aeseclus hippocastanum L. and Hamamelis virginia L. were found to have strong active-oxygen scavenging activity of and protective activity against cell damage induced by active oxygen. Both Aeseclus hippocastanum L. and Hamamelis virginiana L. are proposed as potent plant extracts with potential application as anti-aging or anti-wrinkle material for the skin.

SOD activity of carboxyfullerenes predicts their neuroprotective efficacy: A structure-activity study

PubMed Central

Ali, Sameh Saad; Hardt, Joshua I.; Dugan, Laura L.

2008-01-01

Superoxide radical anion is a biologically important oxidant that has been linked to tissue injury and inflammation in several diseases. Here we carried out a structure-activity study on 6 different carboxyfullerene superoxide dismutase (SOD) mimetics with distinct electronic and biophysical characteristics. Neurotoxicity via NMDA receptors, which involves intracellular superoxide, was used as a model to evaluate structure-activity relationships between reactivity towards superoxide and neuronal rescue by these drugs. A significant correlation between neuroprotection by carboxyfullerenes and their ki towards superoxide radical was observed. Computer-assistant molecular modeling demonstrated that the reactivity towards superoxide is sensitive to changes in dipole moment which are dictated not only by the number of carboxyl groups, but also by their distribution on the fullerene ball. These results indicate that the SOD activity of these cell-permeable compounds predicts neuroprotection, and establishes a structure-activity relationship to aid in future studies on the biology of superoxide across disciplines. PMID:18656425

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.

PubMed

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

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

PubMed

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

2008-06-11

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

Iron, copper, and manganese complexes with in vitro superoxide dismutase and/or catalase activities that keep Saccharomyces cerevisiae cells alive under severe oxidative stress.

PubMed

Ribeiro, Thales P; Fernandes, Christiane; Melo, Karen V; Ferreira, Sarah S; Lessa, Josane A; Franco, Roberto W A; Schenk, Gerhard; Pereira, Marcos D; Horn, Adolfo

2015-03-01

Due to their aerobic lifestyle, eukaryotic organisms have evolved different strategies to overcome oxidative stress. The recruitment of some specific metalloenzymes such as superoxide dismutases (SODs) and catalases (CATs) is of great importance for eliminating harmful reactive oxygen species (hydrogen peroxide and superoxide anion). Using the ligand HPClNOL {1-[bis(pyridin-2-ylmethyl)amino]-3-chloropropan-2-ol}, we have synthesized three coordination compounds containing iron(III), copper(II), and manganese(II) ions, which are also present in the active site of the above-noted metalloenzymes. These compounds were evaluated as SOD and CAT mimetics. The manganese and iron compounds showed both SOD and CAT activities, while copper showed only SOD activity. The copper and manganese in vitro SOD activities are very similar (IC50~0.4 μmol dm(-3)) and about 70-fold higher than those of iron. The manganese compound showed CAT activity higher than that of the iron species. Analyzing their capacity to protect Saccharomyces cerevisiae cells against oxidative stress (H2O2 and the O2(•-) radical), we observed that all compounds act as antioxidants, increasing the resistance of yeast cells mainly due to a reduction of lipid oxidation. Especially for the iron compound, the data indicate complete protection when wild-type cells were exposed to H2O2 or O2(•-) species. Interestingly, these compounds also compensate for both superoxide dismutase and catalase deficiencies; their antioxidant activity is metal ion dependent, in the order iron(III)>copper(II)>manganese(II). The protection mechanism employed by the complexes proved to be independent of the activation of transcription factors (such as Yap1, Hsf1, Msn2/Msn4) and protein synthesis. There is no direct relation between the in vitro and the in vivo antioxidant activities. Copyright © 2014 Elsevier Inc. All rights reserved.

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

PubMed

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

2011-01-01

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

Simultaneous Fluorescence Visualization of Endoplasmic Reticulum Superoxide Anion and Polarity in Myocardial Cells and Tissue.

PubMed

Xiao, Haibin; Wu, Chuanchen; Li, Ping; Tang, Bo

2018-05-15

Diabetic cardiomyopathy (DCM) is a critical complication of diabetes, the accurate pathogenesis of which remains elusive. It is widely accepted that endoplasmic reticulum (ER) stress and abnormal fluctuations of reactive oxygen species (ROS) are considered to be closely associated with progress of DCM. In addition, DCM-induced changes of myocardial tissue and ROS-derived oxidation of proteins will cause changes of the hydrophilic and hydrophobic domains and may further seriously alter the myocardial cell polarity. Thus, real-time detection of ROS and polarity in ER of live cells and in tissue will contribute to revealing the exact molecular mechanisms of DCM. In this article, we first present an ER-targetable fluorogenic probe termed ER-NAPC for sensitive and selective detection of superoxide anion (O 2 •- ). ER-NAPC can precisely target ER and visualize the increase of O 2 •- level in a live H9c2 cardiomyocyte cell during ER stress. Meanwhile, by combining ER-NAPC with a polarity-sensitive probe, ER-P, we accomplish the simultaneous fluorescence visualization of O 2 •- and polarity in ER of live cells and diabetic myocardial tissue. The dual-color fluorescence imaging results indicate that the O 2 •- level and polarity will synergistically rise during ER stress in live cells and diabetic myocardial tissue. The proposed dual-color imaging strategy may offer a proven methodology for studying coordinated variation of different parameters during ER stress oriented disease.

The stimulation of superoxide anion production in guinea-pig peritoneal macrophages and neutrophils by phorbol myristate acetate, opsonized zymosan and IgG2-containing soluble immune complexes.

PubMed Central

Baxter, M A; Leslie, R G; Reeves, W G

1983-01-01

The kinetics of superoxide anion production in guinea-pig peritoneal macrophages and neutrophils were determined following in vitro stimulation with phorbol myristate acetate (PMA), opsonized zymosan (OZ) and soluble immune complexes of guinea-pig IgG2 (SIC). Superoxide production was recorded as chemiluminescence (CL) arising from the reductive cleavage of lucigenin. With PMA, both macrophages and neutrophils displayed a two-phase response consisting of a rapid initial burst of CL, which preceded ligand ingestion, followed by a plateau in the CL response which persisted for more than 30 min. By contrast, OZ induced a slow progressive increase in CL in both phagocytes which was consistent with the development of an oxidative burst concomitant with ingestion. The phagocytes differed in their responses to SIC, the macrophages displaying CL kinetics similar to those observed with PMA, whereas the neutrophils responded in the manner observed with OZ. The relationship between disparity in the patterns of macrophage and neutrophil CL responses to SIC and differences in their expression of Fc receptors for IgG2 (Coupland & Leslie, 1983) is discussed. PMID:6299935

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

PubMed

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

1987-12-31

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

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

PubMed

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

2017-10-01

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

Superoxide (Electro)Chemistry on Well-Defined Surfaces in Organic Environments

DOE PAGES

Genorio, Bostjan; Staszak-Jirkovský, Jakub; Assary, Rajeev S.; ...

2016-02-09

Efficient chemical transformations in energy conversion and storage systems depend on understanding superoxide anion (O 2 –) electrochemistry at atomic and molecular levels. Here, in this work, a combination of experimental and theoretical techniques are used for rationalizing, and ultimately understanding, the complexity of superoxide anion (electro)chemistry in organic environments. By exploring the O 2 + e – ↔ O 2 – reaction on well-characterized metal single crystals (Au, Pt, Ir), Pt single crystal modified with a single layer of graphene (Graphene@Pt(111)), and glassy carbon (GC) in 1,2 dimethoxyethane (DME) electrolytes, we demonstrate that (i) the reaction is an outer-spheremore » process; (ii) the reaction product O 2 – can “attack” any part of the DME molecule, i.e., the C–O bond via nucleophilic reaction and the C–H bond via radical hydrogen abstraction; (iii) the adsorption of carbon-based decomposition products and the extent of formation of a “solid electrolyte interface” (“SEI”) increases in the same order as the reactivity of the substrate, i.e., Pt(hkl)/Ir(hkl) » Au(hkl)/GC > Gaphene@Pt(111); and (iv) the formation of the “SEI” layer leads to irreversible superoxide electrochemistry on Pt(hkl) and Ir(hkl) surfaces. In conclusion, we believe this fundamental insight provides a pathway for the rational design of stable organic solvents that are urgently needed for the development of a new generation of reliable and affordable battery systems.« less

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

NASA Astrophysics Data System (ADS)

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

2018-03-01

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

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

PubMed

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

2018-01-01

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

Honokiol Dimers and Magnolol Derivatives with New Carbon Skeletons from the Roots of Magnolia officinalis and Their Inhibitory Effects on Superoxide Anion Generation and Elastase Release

PubMed Central

Chen, Hung-Chung; Kuo, Ping-Chung; Lee, E-Jian; Lee, Kuo-Hsiung; Wu, Tian-Shung

2013-01-01

Two honokiol dimers, houpulins A and B (1 and 2), and two magnolol derivatives, houpulins C and D (3 and 4), were isolated and characterized from an ethanol extract obtained from the roots of Magnolia officinalis. The chemical structures were determined based on spectroscopic and physicochemical analyses, which included 1D and 2D NMR, as well as mass spectrometry data. These four oligomers possess new carbon skeletons postulated to be biosynthesized from the coupling of three or four C6-C3 subunits. In addition, the new oligomers were evaluated for inhibition of superoxide anion generation and elastase release, and houpulin B (2) was identified as a new anti-inflammatory lead compound. PMID:23667420

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

PubMed Central

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

2018-01-01

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

Determination of superoxide dismutase mimetic activity in common culinary herbs.

PubMed

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.

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

PubMed

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

2015-12-16

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

An anion channel in Arabidopsis hypocotyls activated by blue light

NASA Technical Reports Server (NTRS)

Cho, M. H.; Spalding, E. P.; Evans, M. L. (Principal Investigator)

1996-01-01

A rapid, transient depolarization of the plasma membrane in seedling stems is one of the earliest effects of blue light detected in plants. It appears to play a role in transducing blue light into inhibition of hypocotyl (stem) elongation, and perhaps other responses. The possibility that activation of a Cl- conductance is part of the depolarization mechanism was raised previously and addressed here. By patch clamping hypocotyl cells isolated from dark-grown (etiolated) Arabidopsis seedlings, blue light was found to activate an anion channel residing at the plasma membrane. An anion-channel blocker commonly known as NPPB 15-nitro-2-(3-phenylpropylamino)-benzoic acid] potently and reversibly blocked this anion channel. NPPB also blocked the blue-light-induced depolarization in vivo and decreased the inhibitory effect of blue light on hypocotyl elongation. These results indicate that activation of this anion channel plays a role in transducing blue light into growth inhibition.

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

PubMed

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

2018-05-01

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

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

PubMed

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

2015-11-05

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

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

PubMed

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

2003-12-26

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

Differential modulation of microglia superoxide anion and thromboxane B2 generation by the marine manzamines

PubMed Central

Mayer, Alejandro MS; Hall, Mary L; Lynch, Sean M; Gunasekera, Sarath P; Sennett, Susan H; Pomponi, Shirley A

2005-01-01

Background Thromboxane B2 (TXB2) and superoxide anion (O2-) are neuroinflammatory mediators that appear to be involved in the pathogenesis of several neurodegenerative diseases. Because activated-microglia are the main source of TXB2 and O2- in these disorders, modulation of their synthesis has been hypothesized as a potential therapeutic approach for neuroinflammatory disorders. Marine natural products have become a source of novel agents that modulate eicosanoids and O2- generation from activated murine and human leukocytes. With the exception of manzamine C, all other manzamines tested are characterized by a complex pentacyclic diamine linked to C-1 of the β-carboline moiety. These marine-derived alkaloids have been reported to possess a diverse range of bioactivities including anticancer, immunostimulatory, insecticidal, antibacterial, antimalarial and antituberculosis activities. The purpose of this investigation was to conduct a structure-activity relationship study with manzamines (MZ) A, B, C, D, E and F on agonist-stimulated release of TXB2 and O2- from E. coli LPS-activated rat neonatal microglia in vitro. Results The manzamines differentially attenuated PMA (phorbol 12-myristate 13-acetate)-stimulated TXB2 generation in the following order of decreasing potency: MZA (IC50 <0.016 μM) >MZD (IC50 = 0.23 μM) >MZB (IC50 = 1.6 μM) >MZC (IC50 = 2.98 μM) >MZE and F (IC50 >10 μM). In contrast, there was less effect on OPZ (opsonized zymosan)-stimulated TXB2 generation: MZB (IC50 = 1.44 μM) >MZA (IC50 = 3.16 μM) >MZC (IC50 = 3.34 μM) >MZD, MZE and MZF (IC50 >10 μM). Similarly, PMA-stimulated O2- generation was affected differentially as follows: MZD (apparent IC50<0.1 μM) >MZA (IC50 = 0.1 μM) >MZB (IC50 = 3.16 μM) >MZC (IC50 = 3.43 μM) >MZE and MZF (IC50 >10 μM). In contrast, OPZ-stimulated O2- generation was minimally affected: MZB (IC50 = 4.17 μM) >MZC (IC50 = 9.3 μM) >MZA, MZD, MZE and MZF (IC50 > 10 μM). From the structure-activity

Synergism between arsenite and proteasome inhibitor MG132 over cell death in myeloid leukaemic cells U937 and the induction of low levels of intracellular superoxide anion

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

Lombardo, Tomás; Cavaliere, Victoria; Costantino, Susana N.

Increased oxygen species production has often been cited as a mechanism determining synergism on cell death and growth inhibition effects of arsenic-combined drugs. However the net effect of drug combination may not be easily anticipated solely from available knowledge of drug-induced death mechanisms. We evaluated the combined effect of sodium arsenite with the proteasome inhibitor MG132, and the anti-leukaemic agent CAPE, on growth-inhibition and cell death effect in acute myeloid leukaemic cells U937 and Burkitt's lymphoma-derived Raji cells, by the Chou–Talalay method. In addition we explored the association of cytotoxic effect of drugs with changes in intracellular superoxide anion (O{submore » 2}{sup −}) levels. Our results showed that combined arsenite + MG132 produced low levels of O{sub 2}{sup −} at 6 h and 24 h after exposure and were synergic on cell death induction in U937 cells over the whole dose range, although the combination was antagonistic on growth inhibition effect. Exposure to a constant non-cytotoxic dose of 80 μM hydrogen peroxide together with arsenite + MG132 changed synergism on cell death to antagonism at all effect levels while increasing O{sub 2}{sup −} levels. Arsenite + hydrogen peroxide also resulted in antagonism with increased O{sub 2}{sup −} levels in U937 cells. In Raji cells, arsenite + MG132 also produced low levels of O{sub 2}{sup −} at 6 h and 24 h but resulted in antagonism on cell death and growth inhibition. By contrast, the combination arsenite + CAPE showed high levels of O{sub 2}{sup −} production at 6 h and 24 h post exposure but resulted in antagonism over cell death and growth inhibition effects in U937 and Raji cells. We conclude that synergism between arsenite and MG132 in U937 cells is negatively associated to O{sub 2}{sup −} levels at early time points after exposure. -- Highlights: ► Arsenic combined cytotoxic and anti-proliferative effects by Chou–Talalay method. ► Cytotoxic effect

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

PubMed Central

Broadley, C.; Hoover, R. L.

1989-01-01

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

Amine fluoride gel affects the viability and the generation of superoxide anions in human polymorphonuclear leukocytes: an in vitro study.

PubMed

Knoll-Köhler, Elisabeth; Stiebel, Juliane

2002-08-01

Amine hydrofluorides are widely used to prevent caries. As an acidulated gel, they were also studied for their applicability to reduce pathogenic bacteria in periodontal pockets. We assessed the toxicity of this pharmaceutical amine hydrofluoride preparation on human polymorphonuclear leukocytes in vitro by measuring Trypan blue exclusion and the generation of superoxide anions (O2) by the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) after a 3-min contact with gel. Depending on the experimental conditions, gel dilutions up to 1.3 x 10(4) resulted in an increase in Trypan blue-colored cells and liberation of beta-glucuronidase. Dilutions between 3 x 10(4) and 1 x 10(5) augmented the fMLP-mediated O2- generation, which could be prevented by Ca2+ chelation with BAPTA-AM (1,2'-bis (o-aminophenoxyethane-N.N.N'.N'-tetraacetic acid tetra (acetoxymethyl) ester) and ethyleneglycoltetraacetic acid (EGTA) or inhibition of protein kinase C (PKC) with staurosporine and bisindolylmaleimide I. respectively. Compared with data published on the minimal inhibitory concentration for periodontal pathogenic bacteria, the cytotoxicity of amine hydrofluorides on eukaryotic cells is much greater and thus of consequence for their clinical use.

Uncaria rhynchophylla and Rhynchophylline inhibit c-Jun N-terminal kinase phosphorylation and nuclear factor-kappaB activity in kainic acid-treated rats.

PubMed

Hsieh, Ching-Liang; Ho, Tin-Yun; Su, Shan-Yu; Lo, Wan-Yu; Liu, Chung-Hsiang; Tang, Nou-Ying

2009-01-01

Our previous studies have shown that Uncaria rhynchophylla (UR) can reduce epileptic seizures. We hypothesized that UR and its major component rhynchophylline (RH), reduce epileptic seizures in rats treated with kainic acid (KA) by inhibiting nuclear factor-kappaB (NF-kappaB) and activator-protein-1 (AP-1) activity, and by eliminating superoxide anions. Therefore, the level of superoxide anions and the DNA binding activities of NF-kappaB and AP-1 were measured. Sprague-Dawley (SD) rats were pre-treated with UR (1.0 g/kg, i.p.), RH (0.25 mg/kg, i.p.), or valproic acid (VA, 250 mg/kg, i.p.) for 3 days and then KA was administered intra-peritoneal (i.p.). The results indicated that UR, RH, and VA can reduce epileptic seizures and the level of superoxide anions in the blood. Furthermore, KA was demonstrated to induce the DNA binding activities of NF-kappaB and AP-1. However, these inductions were inhibited by pre-treatment with UR, RH, or VA for 3 days. Moreover, UR and RH were shown to be involved in the suppression of c-Jun N-terminal kinase (JNK) phosphorylation. This study suggested that UR and RH have antiepileptic effects in KA-induced seizures and are associated with the regulation of the innate immune system via a reduction in the level of superoxide anions, JNK phosphorylation, and NF-kappaB activation.

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

PubMed Central

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

2017-01-01

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

Globins Scavenge Sulfur Trioxide Anion Radical*

PubMed Central

Gardner, Paul R.; Gardner, Daniel P.; Gardner, Alexander P.

2015-01-01

Ferrous myoglobin was oxidized by sulfur trioxide anion radical (STAR) during the free radical chain oxidation of sulfite. Oxidation was inhibited by the STAR scavenger GSH and by the heme ligand CO. Bimolecular rate constants for the reaction of STAR with several ferrous globins and biomolecules were determined by kinetic competition. Reaction rate constants for myoglobin, hemoglobin, neuroglobin, and flavohemoglobin are large at 38, 120, 2,600, and ≥ 7,500 × 106 m−1 s−1, respectively, and correlate with redox potentials. Measured rate constants for O2, GSH, ascorbate, and NAD(P)H are also large at ∼100, 10, 130, and 30 × 106 m−1 s−1, respectively, but nevertheless allow for favorable competition by globins and a capacity for STAR scavenging in vivo. Saccharomyces cerevisiae lacking sulfite oxidase and deleted of flavohemoglobin showed an O2-dependent growth impairment with nonfermentable substrates that was exacerbated by sulfide, a precursor to mitochondrial sulfite formation. Higher O2 exposures inactivated the superoxide-sensitive mitochondrial aconitase in cells, and hypoxia elicited both aconitase and NADP+-isocitrate dehydrogenase activity losses. Roles for STAR-derived peroxysulfate radical, superoxide radical, and sulfo-NAD(P) in the mechanism of STAR toxicity and flavohemoglobin protection in yeast are suggested. PMID:26381408

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

PubMed

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

2011-01-01

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

Antioxidant and analgesic activities of turpentine of Pinus nigra Arn. subsp. pallsiana (Lamb.) Holmboe.

PubMed

Gülçin, Ilhami; Büyükokuroglu, M Emin; Oktay, Münir; Küfrevioglu, O Irfan

2003-05-01

The aim of this study is to examine possible antioxidant and analgesic activities of turpentine exudes from Pinus nigra Arn. subsp. pallsiana (Lamb.) Holmboe (TPN). Total antioxidant activity, reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities were studied. The total antioxidant activity increased with the increasing amount of extracts (100, 300, and 500 microg) added to linoleic acid emulsion. All of the doses of TPN showed higher antioxidant activity than alpha-tocopherol. The samples showed 49, 70, and 91% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, the 300 microg of alpha-tocopherol showed 40% inhibition on peroxidation of linoleic acid emulsion. There is correlation between antioxidant activity and the reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities. Like antioxidant activity, the reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities of TPN depending on concentration and increasing with increased concentration of TPN. These properties may be the major reasons for the inhibition of lipid peroxidation. The results obtained in the present study indicate that the TPN has a potential source of natural antioxidant. In addition, analgesic effect of TPN was investigated in present study and TPN had strong analgesic effect. The analgesic effect of TPN compared with metamizol as a standard analgesic compound.

Polyphenolic content and antioxidant activity of some wild Saudi Arabian Asteraceae plants.

PubMed

Shahat, Abdelaaty A; Ibrahim, Abeer Y; Elsaid, Mansour S

2014-07-01

To study the antioxidant properties of crude extract of different Asteraceae plants. The antioxidant properties of six extracts were evaluated using different antioxidant tests, including free radical scavenging, reducing power, metal chelation, superoxide anion radical scavenging, total antioxidant capacity and inhibition of lipid peroxidation activities. Picris cyanocarpa (P. cyanocarpa) and Anthemis deserti (A. deserti) had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger while Achillia fragrantissima (A. fragrantissima) and Artemissia monosperma (A. monosperma) were the most efficient as ion chelator (100% at 100, 200 and 400 μg/mL) A. fragrantissima and Rhantarium appoposum (R. appoposum) showed 100% inhibition on peroxidation of linoleic acid emulsion at 200 and 400 μg/mL, while butylatedhydroxy toluene and ascorbic acid showed 100 and 95% inhibition percentage at 400 μg/mL, respectively. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyl toluene and ascorbic acid. In most tests P. cyanocarpa and A. deserti had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Simple Biological Systems for Assessing the Activity of Superoxide Dismutase Mimics

PubMed Central

Tovmasyan, Artak; Reboucas, Julio S.

2014-01-01

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

Dual-Ratiometric Fluorescent Nanoprobe for Visualizing the Dynamic Process of pH and Superoxide Anion Changes in Autophagy and Apoptosis.

PubMed

Yang, Limin; Chen, Yuanyuan; Yu, Zhengze; Pan, Wei; Wang, Hongyu; Li, Na; Tang, Bo

2017-08-23

Autophagy and apoptosis are closely associated with various pathological and physiological processes in cell cycles. Investigating the dynamic changes of intracellular active molecules in autophagy and apoptosis is of great significance for clarifying their inter-relationship and regulating mechanism in many diseases. In this study, we develop a dual-ratiometric fluorescent nanoprobe for quantitatively differentiating the dynamic process of superoxide anion (O 2 •- ) and pH changes in autophagy and apoptosis in HeLa cells. A rhodamine B-loaded mesoporous silica core was used as the reference, and fluorescence probes for pH and O 2 •- measurement were doped in the outer layer shell of SiO 2 . Then, chitosan and triphenylphosphonium were modified on the surface of SiO 2 . The experimental results showed that the nanoprobe is able to simultaneously and precisely visualize the changes of mitochondrial O 2 •- and pH in HeLa cells. The kinetics data revealed that the changes of pH and O 2 •- during autophagy and apoptosis in HeLa cells were significantly different. The pH value was decreased at the early stage of apoptosis and autophagy, whereas the O 2 •- level was enhanced at the early stage of apoptosis and almost unchanged at the initial stage of autophagy. At the late stage of apoptosis and autophagy, the concentration of O 2 •- was increased, whereas the pH was decreased at the late stage of autophagy and almost unchanged at the late stage of apoptosis. We hope that the present results provide useful information for studying the effects of O 2 •- and pH in autophagy and apoptosis in various pathological conditions and diseases.

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

PubMed Central

Kondo, Yoshitaka; Masutomi, Hirofumi; Noda, Yoshihiro; Ozawa, Yusuke; Takahashi, Keita; Handa, Setsuko; Maruyama, Naoki; Shimizu, Takahiko; Ishigami, Akihito

2014-01-01

Superoxide dismutase 1 (SOD1) is an antioxidant enzyme that converts superoxide anion radicals into hydrogen peroxide and molecular oxygen. The senescence marker protein-30 (SMP30) is a gluconolactonase that functions as an antioxidant protein in mammals due to its involvement in ascorbic acid (AA) biosynthesis. SMP30 also participates in Ca2+ efflux by activating the calmodulin-dependent Ca2+-pump. To reveal the role of oxidative stress in lipid metabolism defects occurring in non-alcoholic fatty liver disease pathogenesis, we generated SMP30/SOD1-double knockout (SMP30/SOD1-DKO) mice and investigated their survival curves, plasma and hepatic lipid profiles, amounts of hepatic oxidative stress, and hepatic protein levels expressed by genes related to lipid metabolism. While SMP30/SOD1-DKO pups had no growth retardation by 14 days of age, they did have low plasma and hepatic AA levels. Thereafter, 39% and 53% of male and female pups died by 15–24 and 89 days of age, respectively. Compared to wild type, SMP30-KO and SOD1-KO mice, by 14 days SMP30/SOD1-DKO mice exhibited: (1) higher plasma levels of triglyceride and aspartate aminotransferase; (2) severe accumulation of hepatic triglyceride and total cholesterol; (3) higher levels of superoxide anion radicals and thiobarbituric acid reactive substances in livers; and (4) decreased mRNA and protein levels of Apolipoprotein B (ApoB) in livers – ApoB is an essential component of VLDL secretion. These results suggest that high levels of oxidative stress due to concomitant deficiency of SMP30 and/or AA, and SOD1 cause abnormal plasma lipid metabolism, hepatic lipid accumulation and premature death resulting from impaired VLDL secretion. PMID:25003023

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

PubMed Central

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

2011-01-01

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

2,4,6-Trichlorophenylhydrazine Schiff bases as DPPH radical and super oxide anion scavengers.

PubMed

Khan, Khalid Mohammed; Shah, Zarbad; Ahmad, Viqar Uddin; Khan, Momin; Taha, Muhammad; Rahim, Fazal; Ali, Sajjad; Ambreen, Nida; Perveen, Shahnaz; Choudhary, M Iqbal; Voelter, Wolfgang

2012-05-01

Syntheses of thirty 2,4,6-trichlorophenylhydrazine Schiff bases 1-30 were carried out and evaluated for their in vitro DPPH radical and super oxide anion scavenging activities. Compounds 1-30 have shown a varying degree of DPPH radical scavenging activity and their IC50 values range between 4.05-369.30 µM. The compounds 17, 28, 18, 14, 8, 15, 12, 2, 29, and 7 exhibited IC50 values ranging between 4.05±0.06-24.42±0.86 µM which are superior to standard n-propylgallate (IC50=30.12±0.27 µM). Selected compounds have shown a varying degree of superoxide anion radical scavenger activity and their IC50 values range between 91.23-406.90 µM. The compounds 28, 8, 17, 15, and 14, showed IC50 values between 91.23±1.2-105.31±2.29 µM which are superior to standard n-propylgallate (IC50=106.34±1.6 µM).

Reduced superoxide dismutase activity in xeroderma pigmentosum fibroblasts

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

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

1989-10-01

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 ofmore » 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.« less

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

USDA-ARS?s Scientific Manuscript database

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

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

PubMed Central

Yanaga, F; Watson, S P

1994-01-01

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

An extract from berries of Aronia melanocarpa modulates the generation of superoxide anion radicals in blood platelets from breast cancer patients.

PubMed

Kedzierska, Magdalena; Olas, Beata; Wachowicz, Barbara; Stochmal, Anna; Oleszek, Wieslaw; Jeziorski, Arkadiusz; Piekarski, Janusz; Glowacki, Rafal

2009-10-01

Plant antioxidants protect cells against oxidative stress. Because oxidative stress (measured by different biomarkers) is observed in breast cancer patients, the aim of this study was to establish the effects of a polyphenol-rich extract of Aronia melanocarpa (final concentration of 50 microg/mL, 5 min, 37 degrees C) on superoxide anion radicals (O(2)(-*)) and glutathione (GSH) in platelets from patients with breast cancer and in a healthy group in vitro. Generation of O(2)(-*) in platelets before and after incubation with the extract was measured by cytochrome C reduction. Using HPLC, we determined the level of glutathione in blood platelets. We observed a statistically significant increase of biomarkers of oxidative stress such as O(2)(-*) and a decrease in GSH in platelets from patients with breast cancer compared with the healthy group. We showed that the extract from A. melanocarpa added to blood platelets significantly reduced the production of O(2)(-*) in platelets not only from the healthy group but also from patients with breast cancer. Considering the data presented in this study, we have demonstrated the protective role of the extract from A. melanocarpa in patients with breast cancer in vitro. Georg Thieme Verlag KG Stuttgart-New York.

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

PubMed

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

2016-02-19

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

Dissolution and ionization of sodium superoxide in sodium–oxygen batteries

PubMed Central

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

2016-01-01

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

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

PubMed

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.

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

PubMed

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

2018-03-30

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

Superoxide dismutase activity of Cu-bound prion protein

NASA Astrophysics Data System (ADS)

Hodak, Miroslav; Lu, Wenchang; Bernholc, Jerry

2009-03-01

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

Biomaterial-induced alterations of neutrophil superoxide production.

PubMed

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.

Superoxide scavenging activity of pirfenidone-iron complex

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

Mitani, Yoshihiro; Sato, Keizo; Muramoto, Yosuke

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

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

PubMed

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

2007-03-01

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

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

PubMed

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.

Inhibition of nitric oxide synthase expression in activated microglia and peroxynitrite scavenging activity by Opuntia ficus indica var. saboten.

PubMed

Lee, Ming Hong; Kim, Jae Yeon; Yoon, Jeong Hoon; Lim, Hyo Jin; Kim, Tae Hee; Jin, Changbae; Kwak, Wie-Jong; Han, Chang-Kyun; Ryu, Jae-Ha

2006-09-01

Activated microglia by neuronal injury or inflammatory stimulation overproduce nitric oxide (NO) by inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS) such as superoxide anion, resulting in neurodegenerative diseases. The toxic peroxynitrite (ONOO-), the reaction product of NO and superoxide anion further contributes to oxidative neurotoxicity. A butanol fraction obtained from 50% ethanol extracts of Opuntia ficus indica var. saboten (Cactaceae) stem (SK OFB901) and its hydrolysis product (SK OFB901H) inhibited the production of NO in LPS-activated microglia in a dose dependent manner (IC50 15.9, 4.2 microg/mL, respectively). They also suppressed the expression of protein and mRNA of iNOS in LPS-activated microglial cells at higher than 30 microg/mL as observed by western blot analysis and RT-PCR experiment. They also inhibited the degradation of I-kappaB-alpha in activated microglia. Moreover, they showed strong activity of peroxynitrite scavenging in a cell free bioassay system. These results imply that Opuntia ficus indica may have neuroprotective activity through the inhibition of NO production by activated microglial cells and peroxynitrite scavenging activity. Copyright (c) 2006 John Wiley & Sons, Ltd.

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

PubMed

Sirota, T V

2015-01-01

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

Elucidating anionic oxygen activity in lithium-rich layered oxides

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

Xu, Jing; Sun, Meiling; Qiao, Ruimin

Recent research has explored combining conventional transition metal redox with anionic lattice oxygen redox as a new and exciting direction to search for high-capacity lithium-ion cathodes. For this study, we probe the poorly understood electrochemical activity of anionic oxygen from a material perspective by elucidating the effect of the transition metal on oxygen redox activity. We study two lithium-rich layered oxides, specifically lithium nickel metal oxides where metal is either manganese or ruthenium, which possess similar structure and discharge characteristics, but exhibit distinctly different charge profiles. By combining X-ray spectroscopy with operando differential electrochemical mass spectrometry, we reveal completely differentmore » oxygen redox activity in each material, likely resulting from the different interaction between the lattice oxygen and transition metals. This work provides additional insights into the complex mechanism of oxygen redox and development of advanced high-capacity lithium-ion cathodes.« less

Elucidating anionic oxygen activity in lithium-rich layered oxides

DOE PAGES

Xu, Jing; Sun, Meiling; Qiao, Ruimin; ...

2018-03-05

Recent research has explored combining conventional transition metal redox with anionic lattice oxygen redox as a new and exciting direction to search for high-capacity lithium-ion cathodes. For this study, we probe the poorly understood electrochemical activity of anionic oxygen from a material perspective by elucidating the effect of the transition metal on oxygen redox activity. We study two lithium-rich layered oxides, specifically lithium nickel metal oxides where metal is either manganese or ruthenium, which possess similar structure and discharge characteristics, but exhibit distinctly different charge profiles. By combining X-ray spectroscopy with operando differential electrochemical mass spectrometry, we reveal completely differentmore » oxygen redox activity in each material, likely resulting from the different interaction between the lattice oxygen and transition metals. This work provides additional insights into the complex mechanism of oxygen redox and development of advanced high-capacity lithium-ion cathodes.« less

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

PubMed

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

2012-01-01

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

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

PubMed Central

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

2012-01-01

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

EFFECT OF INORGANIC CATIONS ON BACTERICIDAL ACTIVITY OF ANIONIC SURFACTANTS

PubMed Central

Voss, J. G.

1963-01-01

Voss, J. G. (Procter & Gamble Co., Cincinnati, Ohio). Effect of inorganic cations on bactericidal activity of anionic surfactants. J. Bacteriol. 86:207–211. 1963.—The bactericidal effectiveness of two alkyl benzene sulfonates and of three other types of anionic surfactants against Staphylococcus aureus is increased in the presence of low concentrations of divalent cations, especially alkaline earths and metals of group IIB of the periodic table. The cations may act by decreasing the negative charge at the cell surface and increasing adsorption of the surfactant anions, leading to damage to the cytoplasmic membrane and death of the cell. Increased adsorption of surfactant is also found with Escherichia coli, but does not lead to death of the cell. PMID:14058942

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

NASA Technical Reports Server (NTRS)

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

2000-01-01

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

Superoxide and Peroxynitrite in Atherosclerosis

NASA Astrophysics Data System (ADS)

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

1994-02-01

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

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

PubMed

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

2012-12-01

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

Molecular anions.

PubMed

Simons, Jack

2008-07-24

The experimental and theoretical study of molecular anions has undergone explosive growth over the past 40 years. Advances in techniques used to generate anions in appreciable numbers as well as new ion-storage, ion-optics, and laser spectroscopic tools have been key on the experimental front. Theoretical developments on the electronic structure and molecular dynamics fronts now allow one to achieve higher accuracy and to study electronically metastable states, thus bringing theory in close collaboration with experiment in this field. In this article, many of the experimental and theoretical challenges specific to studying molecular anions are discussed. Results from many research groups on several classes of molecular anions are overviewed, and both literature citations and active (in online html and pdf versions) links to numerous contributing scientists' Web sites are provided. Specific focus is made on the following families of anions: dipole-bound, zwitterion-bound, double-Rydberg, multiply charged, metastable, cluster-based, and biological anions. In discussing each kind of anion, emphasis is placed on the structural, energetic, spectroscopic, and chemical-reactivity characteristics that make these anions novel, interesting, and important.

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

PubMed

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

2007-01-01

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

Different activities of Schinus areira L.: anti-inflammatory or pro-inflammatory effect.

PubMed

Davicino, R; Mattar, A; Casali, Y; Anesini, C; Micalizzi, B

2010-12-01

The anti-inflammatory drugs possess many serious side effects at doses commonly prescribed. It is really important to discover novel regulators of inflammation from natural sources with minimal adverse effects. Schinus areira L. is a plant native from South America and is used in folk medicine as an anti-inflammatory herb. For this study, the activity of aqueous extracts on inflammation and the effect on superoxide anion production in mice macrophages were assayed. Aqueous extracts were prepared by soaking herbs in cold water (cold extract), boiling water (infusion), and simmering water (decoction). Cold extract possess an anti-inflammatory activity. Decoction and infusion showed pro-inflammatory activity. Cold extract increased the production of superoxide anion. It has been proposed to use diverse methods to obtain extracts of S. areira L. with different effects. Cold extract, decoction, and infusion could be utilized as extracts or as pharmacological preparations for topical application.

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

PubMed Central

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

1994-01-01

BACKGROUND--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. METHODS--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. RESULTS--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. CONCLUSIONS--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. PMID:8202875

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

PubMed

Xiao, Neng; Gourdin, Gerald; Wu, Yiying

2018-05-22

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

Targeting superoxide dismutase to endothelial caveolae profoundly alleviates inflammation caused by endotoxin.

PubMed

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.

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

PubMed Central

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

2012-01-01

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

New reagent for extraction photomeric determination of anionic surface-active substances

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

Chernova, R.K.; Yastrebova, N.I.; Pankratov, A.N.

1995-02-01

The new reagent 2,6-diphenyl-4-(4-dimethylamino)styrylpyryl chloride is suggested for extraction photometric determination of anionic surface-active substances (SAS). This reagent possesses high sensitivity and selectivity, and can be used for the determination of both individual SAS of any kind and the total amount of anionic SAS. The reagent was used in analysis of highly mineralized statal waters and for the determination of sulfated products in polyoxyethylated alkylphenols.

γ-Secretase Inhibition of Murine Choroidal Neovascularization Is Associated with Reduction of Superoxide and Proinflammatory Cytokines

PubMed Central

Qi, Xiaoping; Cai, Jun; Ruan, Qing; Liu, Li; Boye, Sanford L.; Chen, Zhijuan; Hauswirth, William W.; Ryals, Renee C.; Shaw, Lynn; Caballero, Sergio; Grant, Maria B.

2012-01-01

Purpose. This study aimed to determine whether upregulation of γ-secretase could inhibit laser-induced choroidal neovascularization (CNV) and if this was associated with a reduction in both oxidative stress and proinflammatory cytokines. Methods. γ-Secretase, or its catalytic subunit presenilin 1 (PS1), were upregulated by exposure to either pigment epithelial derived factor (PEDF) or an AAV2 vector containing a PS1 gene driven by a vascular endothelial-cadherin promoter. Retinal endothelial cells were infected with AAV2 or exposed to PEDF in the presence or absence of VEGF and in vitro angiogenesis determined. Mouse eyes either received intravitreal injection of PEDF, DAPT (a γ-secretase inhibitor) or PEDF + DAPT at the time of laser injury, or AAV2 infection 3 weeks before receiving laser burns. Lesion volume was determined 14 days post laser injury. Superoxide generation, antioxidant activity and the production of proinflammatory mediators were assessed. Knockdown of γ-secretase was achieved using siRNA. Results. γ-Secretase upregulation and PS1 overexpression suppressed VEGF-induced in vitro angiogenesis and in vivo laser-induced CNV. This was associated with a reduction in the expression of VEGF and angiogenin 1 together with reduced superoxide anion generation and an increase in MnSOD compared with untreated CNV eyes. PS1 overexpression reduced proinflammatory factors and microglial activation in eyes with CNV compared with control. siRNA inhibition of γ-secretase resulted in increased angiogenesis. Conclusions. γ-Secretase, and in particular PS1 alone, are potent regulators of angiogenesis and this is due in part to stabilizing endogenous superoxide generation and reducing proinflammatory cytokine expression during CNV. PMID:22205609

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

PubMed

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

2017-02-15

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

Biological Superoxide In Manganese Oxide Formation

NASA Astrophysics Data System (ADS)

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

2011-12-01

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

Inactivation of biologically active dna by gamma ray induced superoxide radicals and their dismutation products singlet molecular oxygen and hydrogen peroxide

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

Vanhemmen, J.J.; Meuling, W.J.A.

1975-01-01

The reactivity of gamma ray induced superoxide radicals and dismutation products (singlet molecular oxygen and hydrogen peroxide) with DNA were studied. Superoxide dismutase, which removes superoxide radicals and inhibits the formation of singlet oxygen, protects biologically active DNA (OX174 RF) against inactivation by ionizing radiation. Catalase, which removes hydrogen peroxide, also protects the DNA. Attempts with various chemical sources of singlet oxygen to determine whether this species inactivates DNA did not yield an unequivocal answer. It was concluded that a combination of the protonated form of the superoxide radical and hydrogen peroxide inactivates DNA. (Author) (GRA)

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

PubMed Central

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

2012-01-01

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

Ca(2+)-activated anion channels and membrane depolarizations induced by blue light and cold in Arabidopsis seedlings

NASA Technical Reports Server (NTRS)

Lewis, B. D.; Karlin-Neumann, G.; Davis, R. W.; Spalding, E. P.; Evans, M. L. (Principal Investigator)

1997-01-01

The activation of an anion channel in the plasma membrane of Arabidopsis thaliana hypocotyls by blue light (BL) is believed to be a signal-transducing event leading to growth inhibition. Here we report that the open probability of this particular anion channel depends on cytoplasmic Ca2+ ([Ca2+]cyt) within the concentration range of 1 to 10 microM, raising the possibility that BL activates the anion channel by increasing [Ca2+]cyt. Arabidopsis seedlings cytoplasmically expressing aequorin were generated to test this possibility. Aequorin luminescence did not increase during or after BL, providing evidence that Ca2+ does not play a second-messenger role in the activation of anion channels. However, cold shock simultaneously triggered a large increase in [Ca2+]cyt and a 110-mV transient depolarization of the plasma membrane. A blocker of the anion channel, 5-nitro-2-(3-phenylpropylamino)-benzoic acid, blocked 61% of the cold-induced depolarization without affecting the increase in [Ca2+]cyt. These data led us to propose that cold shock opens Ca2+ channels at the plasma membrane, allowing an inward, depolarizing Ca2+ current. The resulting large increase in [Ca2+]cyt activates the anion channel, which further depolarizes the membrane. Although an increase in [Ca2+]cyt may activate anion channels in response to cold, it appears that BL does so via a Ca(2+)-independent pathway.

Catalase and superoxide dismutase activities after heat injury of listeria monocytogenes

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

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

1988-02-01

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

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

NASA Astrophysics Data System (ADS)

Xing, Da; He, Yonghong; Hao, Min; Chen, Qun

2004-07-01

A novel method of photodynamic diagnosis (PDD) of cancer mediated by chemiluminescence (CL) probe is presented. The mechanism for photodynamic therapy (PDT) involves reactive oxygen species (ROS), such as singlet oxygen (1O2) and superoxide (O2-), generated by during the photochemical process. Both 1O2 and O2- can react with Cypridina luciferin analogue (FCLA), a highly selective CL probe for detecting the ROS. Chemiluminescence from the reaction of FCLA with the ROS, at about 530 nm, was detected by a highly sensitive ICCD system. The CL was markedly inhibited by the addition of 10 mmol/L sodium azide (NaN3) in a sample solution. Similar phenomena, with lesser extents of changes, were observed at the additions of 10 μmol/L superoxide dismutase (SOD), 10 mmol/L mannitol, and 100 μg/mL catalase, respectively. This indicates that the detected CL signals were mainly from ROS generated during the photosensitization reactions. Also, the chemiluminescence method was used to detect the ROS during sonodynamic action, both in vitro and in vivo. ROS formation during sonosensitizations of HpD and ATX-70 were detected using our newly-developed imaging technique, in real time, on tumor bearing animals. This method can provide a new means in clinics for tumor diagnosis.

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

PubMed

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

2017-06-01

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

Anion effects on anti-microbial activity of poly[1-vinyl-3-(2-sulfoethyl imidazolium betaine)].

PubMed

Garg, Godawari; Chauhan, Ghanshyam S; Gupta, Reena; Ahn, J-H

2010-04-01

Recent investigations in the anti-microbial properties of the functional polymers are predominantly focused on the structure of the cationic moieties. In the present study, we investigated that the nature of the anion present in polysulfobetaines affects activity against certain microorganisms and their anti-microbial properties have been rationalized in terms of the structure-activity relationship. Vinyl imidazolium-based polysulfobetaines were prepared by the quaternization of poly(N-vinyl imidazole) with sodium salt of 2-bromo ethanesulfonic acid. The bromide counter anion of the resulting polymer was exchanged with different anions to generate a series of polymers. These were characterized by FTIR, DSC, XRD, SEM, elemental analysis (C, H, N and S) and viscosity measurements. The anti-microbial activity studies were carried against three fungi (Aspergillus niger, Byssochlamys fulva and Mucor circenelliods) and two bacteria (Bacillus coagulans BTS-3 and Pseudomonas aeruginosa BTS-2). The nature of the anion affects the structure of polysulfobetaine by realignment of polymer chains. The anion-dependent anti-microbial properties of polysulfobetaines result from the interaction of the microbes at the polymer interface. Copyright 2009 Elsevier Inc. All rights reserved.

Effects of Liposomal Compositions with Oxidized Dextrans on Functional Activity of U937 Macrophage-Like Cells In Vitro.

PubMed

Kozhin, P M; Chechushkov, A V; Zaitseva, N S; Lemza, A E; Men'shchikova, E B; Troitskii, A V; Shkurupy, V A

2015-11-01

We studied the effects of liposomal pharmaceutical compositions with oxidized dextrans on functional activity of U937 monocyte/macrophage-like cells. Liposomes in the emulsion contained oxidized dextran with a molecular weights of 40 kDa or 70 kDa or isonicotinic acid hydrazide (INAH) conjugated with oxidized dextran (40 kDa). Cell viability was evaluated by MTT test; mitochondrial transmembrane potential and production of superoxide anion and H2O2 were studied by fluorescent methods. The studied compositions exhibited no cytotoxic effect and even improved cell viability and mitochondrial respiration. Liposomes with oxidized 40 kDa dextran, including those with INAH-conjugated dextran, inhibited production of superoxide anion, but increased H2O2 generation.

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

PubMed

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

2017-01-01

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

Copper binding by tetrathiomolybdate attenuates angiogenesis and tumor cell proliferation through the inhibition of superoxide dismutase 1.

PubMed

Juarez, Jose C; Betancourt, Oscar; Pirie-Shepherd, Steven R; Guan, Xiaojun; Price, Melissa L; Shaw, David E; Mazar, Andrew P; Doñate, Fernando

2006-08-15

A second-generation tetrathiomolybdate analogue (ATN-224; choline tetrathiomolybdate), which selectively binds copper with high affinity, is currently completing two phase I clinical trials in patients with advanced solid and advanced hematologic malignancies. However, there is very little information about the mechanism of action of ATN-224 at the molecular level. The effects of ATN-224 on endothelial and tumor cell growth were evaluated in cell culture experiments in vitro. The antiangiogenic activity of ATN-224 was investigated using the Matrigel plug model of angiogenesis. ATN-224 inhibits superoxide dismutase 1 (SOD1) in tumor and endothelial cells. The inhibition of SOD1 leads to inhibition of endothelial cell proliferation in vitro and attenuation of angiogenesis in vivo. The inhibition of SOD1 activity in endothelial cells is dose and time dependent and leads to an increase in the steady-state levels of superoxide anions, resulting in the inhibition of extracellular signal-regulated kinase phosphorylation without apparent induction of apoptosis. In contrast, the inhibition of SOD1 in tumor cells leads to the induction of apoptosis. The effects of ATN-224 on endothelial and tumor cells could be substantially reversed using Mn(III)tetrakis(4-benzoic acid)porphyrin chloride, a catalytic small-molecule SOD mimetic. These data provide a distinct molecular target for the activity of ATN-224 and provide validation for SOD1 as a target for the inhibition of angiogenesis and tumor growth.

A new low molecular weight, MnII-containing scavenger of superoxide anion protects cardiac muscle cells from hypoxia/reoxygenation injury.

PubMed

Nistri, S; Boccalini, G; Bencini, A; Becatti, M; Valtancoli, B; Conti, L; Lucarini, L; Bani, D

2015-01-01

Reperfusion injury after oxygen starvation is a key pathogenic step in ischemic diseases. It mainly consists in oxidative stress, related to mitochondrial derangement and enhanced generation of reactive oxygen species (ROS), mainly superoxide anion (O2(•2)), and peroxynitrite by cells exposed to hypoxia. This in vitro study evaluates whether Mn(II)(4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-diacetate).2H2O, or Mn(II)(Me2DO2A), a new low molecular weight, Mn(II)-containing O2(•) scavenger, has a direct protective action on H9c2 rat cardiac muscle cells subjected to hypoxia and reoxygenation. Mn(II)(Me2DO2A) (1 and 10 μmol/l) was added to the culture medium at reoxygenation and maintained for 2 h. In parallel experiments, the inactive congener Zn(II)(Me2DO2A), in which Zn(II) replaced the functional Mn(II) center in the same organic scaffold, was used as negative control. Mn(II)(Me2DO2A) (10 μmol/l) significantly increased cardiac muscle cell viability (trypan blue assay), improved mitochondrial activity (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide test, membrane potential Δψ), reduced apoptosis (mitochondrial permeability transition pore opening, caspase-3, terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling assay), decreased intracellular ROS levels (2',7'-dichlorodihydrofluorescein diacetate and MitoSOX assays), and decreased protein nitroxidation (nitrotyrosine [NT] expression) and DNA oxidation (8-hydroxy-deoxyguanosine levels). Of note, Zn(II)(Me2DO2A) had no protective effect. The mechanism of Mn(II)(Me2DO2A) relies on concentration-dependent removal of harmful O2(•) generated at reoxygenation from dysfunctional mitochondria in hypoxia-induced cells, as indicated by the MitoSOX assay. This study suggests that Mn(II)(Me2DO2A) is a promising antioxidant drug capable of reducing O2(•)-mediated cell oxidative stress which occurs at reoxygenation after hypoxia. In perspective, Mn(II)(Me2DO2A) might

Escherichia coli avoids high dissolved oxygen stress by activation of SoxRS and manganese-superoxide dismutase.

PubMed

Baez, Antonino; Shiloach, Joseph

2013-03-12

High concentrations of reactive oxygen species (ROS) were reported to cause oxidative stress to E. coli cells associated with reduced or inhibited growth. The high ROS concentrations described in these reports were generated by exposing the bacteria to H2O2 and superoxide-generating chemicals which are non-physiological growth conditions. However, the effect of molecular oxygen on oxidative stress response has not been evaluated. Since the use of oxygen-enriched air is a common strategy to support high density growth of E. coli, it was important to investigate the effect of high dissolved oxygen concentrations on the physiology and growth of E. coli and the way it responds to oxidative stress. To determine the effect of elevated oxygen concentrations on the growth characteristics, specific gene expression and enzyme activity in E. coli, the parental and SOD-deficient strain were evaluated when the dissolved oxygen (dO2) level was increased from 30% to 300%. No significant differences in the growth parameters were observed in the parental strain except for a temporary decrease of the respiration and acetate accumulation profile. By performing transcriptional analysis, it was determined that the parental strain responded to the oxidative stress by activating the SoxRS regulon. However, following the dO2 switch, the SOD-deficient strain activated both the SoxRS and OxyR regulons but it was unable to resume its initial growth rate. The transcriptional analysis and enzyme activity results indicated that when E. coli is exposed to dO2 shift, the superoxide stress regulator SoxRS is activated and causes the stimulation of the superoxide dismutase system. This enables the E. coli to protect itself from the poisoning effects of oxygen. The OxyR protecting system was not activated, indicating that H2O2 did not increase to stressing levels.

Escherichia coli avoids high dissolved oxygen stress by activation of SoxRS and manganese-superoxide dismutase

PubMed Central

2013-01-01

Background High concentrations of reactive oxygen species (ROS) were reported to cause oxidative stress to E. coli cells associated with reduced or inhibited growth. The high ROS concentrations described in these reports were generated by exposing the bacteria to H2O2 and superoxide-generating chemicals which are non-physiological growth conditions. However, the effect of molecular oxygen on oxidative stress response has not been evaluated. Since the use of oxygen-enriched air is a common strategy to support high density growth of E. coli, it was important to investigate the effect of high dissolved oxygen concentrations on the physiology and growth of E. coli and the way it responds to oxidative stress. Results To determine the effect of elevated oxygen concentrations on the growth characteristics, specific gene expression and enzyme activity in E. coli, the parental and SOD-deficient strain were evaluated when the dissolved oxygen (dO2) level was increased from 30% to 300%. No significant differences in the growth parameters were observed in the parental strain except for a temporary decrease of the respiration and acetate accumulation profile. By performing transcriptional analysis, it was determined that the parental strain responded to the oxidative stress by activating the SoxRS regulon. However, following the dO2 switch, the SOD-deficient strain activated both the SoxRS and OxyR regulons but it was unable to resume its initial growth rate. Conclusion The transcriptional analysis and enzyme activity results indicated that when E. coli is exposed to dO2 shift, the superoxide stress regulator SoxRS is activated and causes the stimulation of the superoxide dismutase system. This enables the E. coli to protect itself from the poisoning effects of oxygen. The OxyR protecting system was not activated, indicating that H2O2 did not increase to stressing levels. PMID:23497217

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

PubMed

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

2012-01-03

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

Computational insights into crystal plane dependence of thermal activity of anion (C and N)-substituted titania.

PubMed

V, Sai Phani Kumar; Arya, Rahul; Deshpande, Parag A

2017-11-29

Geometry optimizations of anion (C and N) doped anatase TiO 2 were carried out by using DFT+U calculations. Various anion vacancy sites were examined to study the synergistic effects of anion doping accompanied with anion vacancy formation on lattice oxygen activation. Two non-identical crystal planes (0 0 1) and (1 0 0) were chosen for C and N substitutions. Energetically favoured N-vacancy pairs were identified on TiO 2 surfaces. Substitution of N along with anion vacancies at various sites was energetically more favoured than that of C-doping in bulk TiO 2 while the energies were comparable for surface substitutions. Bond length distributions due to the formation of differential bonds were determined. Net oxygen activation and accompanying reversible oxygen exchange capacities were compared for TiO 2-2x C x and TiO 2-3x N 2x . Substitution of C in the surface exposed (1 0 0) plane of TiO 2 resulted in 47.6% and 23.8% of bond elongation and compression, respectively, resulting in 23.8% of net oxygen activation which was higher when compared to N substitution in the (1 0 0) plane of TiO 2 resulting in a net oxygen activation of 17%.

Self-Activating, Capacitive Anion Intercalation Enables High-Power Graphite Cathodes.

PubMed

Wang, Gang; Yu, Minghao; Wang, Jungang; Li, Debao; Tan, Deming; Löffler, Markus; Zhuang, Xiaodong; Müllen, Klaus; Feng, Xinliang

2018-05-01

Developing high-power cathodes is crucial to construct next-generation quick-charge batteries for electric transportation and grid applications. However, this mainly relies on nanoengineering strategies at the expense of low scalability and high battery cost. Another option is provided herein to build high-power cathodes by exploiting inexpensive bulk graphite as the active electrode material, where anion intercalation is involved. With the assistance of a strong alginate binder, the disintegration problem of graphite cathodes due to the large volume variation of >130% is well suppressed, making it possible to investigate the intrinsic electrochemical behavior and to elucidate the charge storage kinetics of graphite cathodes. Ultrahigh power capability up to 42.9 kW kg -1 at the energy density of >300 Wh kg -1 (based on graphite mass) and long cycling life over 10 000 cycles are achieved, much higher than those of conventional cathode materials for Li-ion batteries. A self-activating and capacitive anion intercalation into graphite is discovered for the first time, making graphite a new intrinsic intercalation-pseudocapacitance cathode material. The finding highlights the kinetical difference of anion intercalation (as cathode) from cation intercalation (as anode) into graphitic carbon materials, and new high-power energy storage devices will be inspired. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Biochemical Characterization, Action on Macrophages, and Superoxide Anion Production of Four Basic Phospholipases A2 from Panamanian Bothrops asper Snake Venom

PubMed Central

Rueda, Aristides Quintero; Rodríguez, Isela González; Arantes, Eliane C.; Setúbal, Sulamita S.; Calderon, Leonardo de A.; Zuliani, Juliana P.; Stábeli, Rodrigo G.; Soares, Andreimar M.

2013-01-01

Bothrops asper (Squamata: Viperidae) is the most important venomous snake in Central America, being responsible for the majority of snakebite accidents. Four basic PLA2s (pMTX-I to -IV) were purified from crude venom by a single-step chromatography using a CM-Sepharose ion-exchange column (1.5 × 15 cm). Analysis of the N-terminal sequence demonstrated that pMTX-I and III belong to the catalytically active Asp49 phospholipase A2 subclass, whereas pMTX-II and IV belong to the enzymatically inactive Lys49 PLA2s-like subclass. The PLA2s isolated from Panama Bothrops asper venom (pMTX-I, II, III, and IV) are able to induce myotoxic activity, inflammatory reaction mainly leukocyte migration to the muscle, and induce J774A.1 macrophages activation to start phagocytic activity and superoxide production. PMID:23509779

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

PubMed

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

2004-02-01

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

Effects of ZCR-2060 on allergic airway inflammation and cell activation in guinea-pigs.

PubMed

Abe, T; Yoshida, K; Omata, T; Segawa, Y; Matsuda, K; Nagai, H

1994-11-01

The effects of 2-(2-(4-(diphenylmethyl)-1-piperadinyl) ethoxy) benzoic acid malate (ZCR-2060) on allergic airway inflammation and inflammatory cell activation in guinea-pigs were studied. Allergic airway inflammation was induced by inhalation of antigen into actively-sensitized animals and the increase in inflammatory cells into bronchoalveolar lavage fluid (BALF) was measured. Aeroantigen-induced infiltration of inflammatory cells, especially eosinophils and neutrophils, in BALF gradually increased, and reached a peak at 6 or 9 h after the challenge. ZCR-2060 (1 mg kg-1 p.o.) clearly inhibited the increase of eosinophil numbers in BALF. Moreover, the effect of ZCR-2060 on inflammatory cell activation in terms of chemotaxis and superoxide generation in-vitro was studied. ZCR-2060 (10(-6)-10(-4) M) inhibited the platelet-activating factor (PAF)-induced chemotaxis of eosinophils and neutrophils, but did not inhibit the leukotriene B4-induced chemotaxis of eosinophils and the formyl-Met-Leu-Phe-induced chemotaxis of neutrophils. PAF-induced superoxide anion generation by eosinophils, neutrophils and alveolar macrophages was inhibited by ZCR-2060 (10(-6)-10(-4) M). However, ZCR-2060 did not affect phorbol myristate acetate-induced superoxide anion generation by eosinophils, neutrophils and alveolar macrophages. These results indicate that ZCR-2060 inhibits allergic airway inflammation, and PAF-induced inflammatory cell activation in guinea-pigs. ZCR-2060 may prove useful for the treatment of allergic airway inflammation or allergic disorders, especially inflammatory cell infiltration and activation.

Effect of ethyleneoxide groups of anionic surfactants on lipase activity.

PubMed

Magalhães, Solange S; Alves, Luís; Sebastião, Marco; Medronho, Bruno; Almeida, Zaida L; Faria, Tiago Q; Brito, Rui M M; Moreno, Maria J; Antunes, Filipe E

2016-09-01

The use of enzymes in laundry and dish detergent products is growing. Such tendency implies dedicated studies to understand surfactant-enzyme interactions. The interactions between surfactants and enzymes and their impact on the catalytic efficiency represent a central problem and were here evaluated using circular dichroism, dynamic light scattering, and enzyme activity determinations. This work focuses on this key issue by evaluating the role of the ethyleneoxide (EO) groups of anionic surfactants on the structure and activity of a commercial lipase, and by focusing on the protein/surfactant interactions at a molecular level. The conformational changes and enzymatic activity of the protein were evaluated in the presence of sodium dodecyl sulfate (SDS also denoted as SLE 0 S) and of sodium lauryl ether sulfate with two EO units (SLE 2 S). The results strongly suggest that the presence of EO units in the surfactant polar headgroup determines the stability and the activity of the enzyme. While SDS promotes enzyme denaturation and consequent loss of activity, SLE 2 S preserves the enzyme structure and activity. The data further highlights that the electrostatic interactions among the protein groups are changed by the presence of the adsorbed anionic surfactants being such absorption mainly driven by hydrophobic interactions. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1276-1282, 2016. © 2016 American Institute of Chemical Engineers.

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

PubMed

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

2017-07-21

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

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

PubMed

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.

Anion channels: master switches of stress responses.

PubMed

Roelfsema, M Rob G; Hedrich, Rainer; Geiger, Dietmar

2012-04-01

During stress, plant cells activate anion channels and trigger the release of anions across the plasma membrane. Recently, two new gene families have been identified that encode major groups of anion channels. The SLAC/SLAH channels are characterized by slow voltage-dependent activation (S-type), whereas ALMT genes encode rapid-activating channels (R-type). Both S- and R-type channels are stimulated in guard cells by the stress hormone ABA, which leads to stomatal closure. Besides their role in ABA-dependent stomatal movement, anion channels are also activated by biotic stress factors such as microbe-associated molecular patterns (MAMPs). Given that anion channels occur throughout the plant kingdom, they are likely to serve a general function as master switches of stress responses. Copyright © 2012 Elsevier Ltd. All rights reserved.

Antimicrobial and antioxidant activities of Flammulina velutipes polysaccharides and polysaccharide-iron(III) complex [corrected].

PubMed

Dong, Ya-Ru; Cheng, Shu-Jie; Qi, Guo-Hong; Yang, Zhi-Ping; Yin, Shi-Yu; Chen, Gui-Tang

2017-04-01

FVP is polysacchrides obtained from Flammulina velutipes. A polysacchride named FVP2 was isolated from FVP by DEAE cellulose-52 chromatography and Sephadex G-100 size-exclusion chromatography. FVP-Fe and FVP2-Fe were synthesized by neutralization of FeCl 3 carbohydrate solution. The antibacterial and antifungal activities of FVP, FVP2, FVP-Fe, FVP2-Fe were investigated and their antioxidant effects on hydroxyl, 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide anion, 2,2'-azobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, reducing power, inhibition of malondialdehyde (MDA) were assessed in vitro. The results suggested that FVP-Fe and FVP2-Fe significantly suppressed the growth of bacteria Staphylococcus aureus, Escherichia coli, and Bacillus subtilis, and have relatively strong antioxidant activity to scavenge superoxide anion radical. In addition, FVP exhibited strong antioxidant activity to eliminate hydroxyl, DPPH, ABTS radicals, had high reducing power and inhibited the MDA production of health mice liver homogenate induced by auto-oxidation and Fe 2+ -H 2 O 2 system. Copyright © 2016 Elsevier Ltd. All rights reserved.

Air Revitalization Using Superoxides

NASA Technical Reports Server (NTRS)

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

1988-01-01

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

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

PubMed

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

1984-03-29

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

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

PubMed

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

2015-05-21

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

Antioxidant activity of methanol extract of Helichrysum foetidum Moench.

PubMed

Tirillini, Bruno; Menghini, Luigi; Leporini, Lidia; Scanu, Nadia; Marino, Stefania; Pintore, Giorgio

2013-01-01

Methanol extract of Helichrysum foetidum Moench (Asteraceae) was investigated for antioxidative properties. The antioxidant activities were investigated by 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging, ß-carotene/linoleic acid assay, scavenging of hydrogen peroxide (HRPO test), superoxide anion scavenging (S.A.S. test) and hypochlorous acid scavenging (taurine test). The antioxidant activity was reported as IC50 and reveals Trolox-like antioxidative effects.

Calcium and Superoxide-Mediated Pathways Converge to Induce Nitric Oxide-Dependent Apoptosis in Mycobacterium fortuitum-Infected Fish Macrophages.

PubMed

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.

A Mitochondrial Superoxide Signal Triggers Increased Longevity in Caenorhabditis elegans

PubMed Central

Yang, Wen; Hekimi, Siegfried

2010-01-01

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

[Active forms of oxygen and nitrogen in blood cells of patients with rheumatoid arthritis: effect of laser therapy].

PubMed

Ostrakhovich, E A; Ilich-Stoianovich, O; Afanas'ev, I B

2001-01-01

Infrared pulse laser therapy was studied for its impact on the production of active forms of oxygen and nitrogen by neutrophils from patients with rheumatoid arthritis (RA). The authors determined the non-activated and PMA-activated production of superoxide anion-radical, peroxynitrite, peripheral neurophilic NAD.PH-oxidase and superoxide dismutase activities, and the red blood cell concentrations of reduced glutathione. Before therapy, non-activation RA neurophilic production of superoxide was much higher than in donors. Laser therapy made this parameter normal. Similarly, neutrophilic peroxynitrite production (defined by dihydrorhodamine oxidation) in RA patients was 1.7 times higher than the normal values. IF-laser therapy decreased peroxynitrite production to the values observed in donors. It is important that the therapy caused increased SOD activity (that was lower in RA patients prior to therapy) up to apparently control values. Thus, IF-laser therapy has a certain antioxidative effect by increasing SOD activity in RA patients' blood cells and reducing the production of highly reactive oxygen and nitrogen forms.

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

PubMed

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

2004-10-08

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

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

PubMed

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

1992-01-05

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

Radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum.

PubMed

Yu, Huahua; Liu, Xiguang; Xing, Ronge; Liu, Song; Li, Cuiping; Li, Pengcheng

2005-05-16

In this study, radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum (R. esculentum) was assayed including superoxide anion radical and hydroxyl radical scavenging. The protein samples showed strong scavenging activity on superoxide anion radical and values EC50 of full protein (FP), first fraction (FF), second fraction (SF), and 30% (NH4)2 SO4 precipitate (Fr-1) were 2.65, 7.28, 1.10, and 22.51 microg/mL, respectively, while values EC50 of BHA, BHT, and alpha-tocopherol were 31, 61, and 88 microg/mL, respectively. Also, the protein samples had strong scavenging effect on hydroxyl radical and the values EC50 of FP, FF, SF, Fr-1, and Fr-2 were 48.91, 27.72, 1.82, 16.36, and 160.93 microg/mL, but values EC50 of Vc and mannitol were 1907 and 4536 microg/mL, respectively. Of the five protein samples, SF had the strongest radical scavenging activity and may have a use as a possible supplement in the food and pharmaceutical industries. The radical scavenging activity was stable at high temperature so that R. esculentum may be used as a kind of natural functional food.

Suppression of bactericidal activity of human polymorphonuclear leukocytes by Bacteroides gingivalis.

PubMed Central

Yoneda, M; Maeda, K; Aono, M

1990-01-01

The direct effects of the culture supernatant of oral microorganisms on the bactericidal activity of human polymorphonuclear leukocytes (PMNs) were investigated. The bactericidal activity of PMNs, which were preincubated with the supernatant of Bacteroides gingivalis, Bacteroides intermedius, Bacteroides melaninogenicus or phosphate-buffered saline, was examined by counting the surviving bacteria. B. gingivalis-treated PMNs were found to have a diminished ability for killing bacteria in the presence or absence of serum. The chemiluminescence response of PMNs, which were preincubated with the culture supernatant of B. gingivalis, was strikingly reduced compared with that of PMNs preincubated with phosphate-buffered saline or other bacterial culture supernatants. The production of superoxide anion (O2-) by PMNs stimulated with either formyl-methionyl-leucyl-phenylalanine or phorbol myristate acetate was reduced in both cases after the PMNs were preincubated with the culture supernatant of B. gingivalis. However, it was observed that there was more reduction in superoxide anion (O2-) production stimulated with formyl-methionyl-leucyl-phenylalanine compared with that stimulated with phorbol myristate acetate. These results suggest that B. gingivalis releases a factor which interferes with the bactericidal activity of PMNs by modulating the generation of reactive oxygen species. These suppressive effects on bactericidal activity may be important in the pathogenesis of this microorganism. PMID:2153632

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

PubMed Central

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

2009-01-01

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(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. 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. PMID:19878539

Competition between Anion Binding and Dimerization Modulates Staphylococcus aureus Phosphatidylinositol-specific Phospholipase C Enzymatic Activity*

PubMed Central

Cheng, Jiongjia; Goldstein, Rebecca; Stec, Boguslaw; Gershenson, Anne; Roberts, Mary F.

2012-01-01

Staphylococcus aureus phosphatidylinositol-specific phospholipase C (PI-PLC) is a secreted virulence factor for this pathogenic bacterium. A novel crystal structure shows that this PI-PLC can form a dimer via helix B, a structural feature present in all secreted, bacterial PI-PLCs that is important for membrane binding. Despite the small size of this interface, it is critical for optimal enzyme activity. Kinetic evidence, increased enzyme specific activity with increasing enzyme concentration, supports a mechanism where the PI-PLC dimerization is enhanced in membranes containing phosphatidylcholine (PC). Mutagenesis of key residues confirm that the zwitterionic phospholipid acts not by specific binding to the protein, but rather by reducing anionic lipid interactions with a cationic pocket on the surface of the S. aureus enzyme that stabilizes monomeric protein. Despite its structural and sequence similarity to PI-PLCs from other Gram-positive pathogenic bacteria, S. aureus PI-PLC appears to have a unique mechanism where enzyme activity is modulated by competition between binding of soluble anions or anionic lipids to the cationic sensor and transient dimerization on the membrane. PMID:23038258

The Antiozonant Ethylenediurea Does Not Act via Superoxide Dismutase Induction in Bean 1

PubMed Central

Pitcher, Lynne H.; Brennan, Eileen; Zilinskas, Barbara A.

1992-01-01

It has been proposed that the mode of action of ethylenediurea, a very effective antiozonant, is via an increase in the antioxidant enzyme superoxide dismutase (EH Lee, JH Bennett [1982] Plant Physiol 69: 1444-1449). Data presented here refute that hypothesis. No ethylenediurea-associated increases in Cu/Zn-superoxide dismutase or Mn-superoxide dismutase activity, nor in steady-state Cu/Zn-superoxide dismutase protein levels, were found in soluble extracts of bean (Phaseolus vulgaris L. cv Bush Blue Lake 290) leaves. However, the cytosolic Cu/Zn-superoxide dismutase increased as a result of ozone fumigation and subsequent injury. Also noted was a developmentally related difference between chloroplastic and cytosolic Cu/Zn-superoxide dismutase, the latter declining during maturation of the leaf. ImagesFigure 1Figure 3 PMID:16669049

Phospholipase A2 activity-dependent and -independent fusogenic activity of Naja nigricollis CMS-9 on zwitterionic and anionic phospholipid vesicles.

PubMed

Chiou, Yi-Ling; Chen, Ying-Jung; Lin, Shinne-Ren; Chang, Long-Sen

2011-11-01

CMS-9, a phospholipase A(2) (PLA(2)) from Naja nigricollis venom, induced the death of human breast cancer MCF-7 cells accompanied with the formation of cell clumps without clear boundaries between cells. Annexin V-FITC staining indicated that abundant phosphatidylserine appeared on the outer membrane of MCF-7 cell clumps, implying the possibility that CMS-9 may promote membrane fusion via anionic phospholipids. To validate this proposition, fusogenic activity of CMS-9 on vesicles composed of zwitterionic phospholipid alone or a combination of zwitterionic and anionic phospholipids was examined. Although CMS-9-induced fusion of zwitterionic phospholipid vesicles depended on PLA(2) activity, CMS-9-induced fusion of vesicles containing anionic phospholipids could occur without the involvement of PLA(2) activity. Membrane-damaging activity of CMS-9 was associated with its fusogenicity. Moreover, CMS-9 induced differently membrane leakage and membrane fusion of vesicles with different compositions. Membrane fluidity and binding capability with phospholipid vesicles were not related to the fusogenicity of CMS-9. However, membrane-bound conformation and mode of CMS-9 depended on phospholipid compositions. Collectively, our data suggest that PLA(2) activity-dependent and -independent fusogenicity of CMS-9 are closely related to its membrane-bound modes and targeted membrane compositions. Copyright © 2011 Elsevier Ltd. All rights reserved.

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

PubMed

Stanford, Katherine R; Taylor-Clark, Thomas E

2018-01-01

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

Spectroscopic studies on the antioxidant activity of p-coumaric acid

NASA Astrophysics Data System (ADS)

Kiliç, Ismail; Yeşiloğlu, Yeşim

2013-11-01

p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPHrad scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties.

Anti-inflammatory effects of tobramycin and a copper–tobramycin complex with superoxide dismutase-like activity

PubMed Central

Gziut, M; MacGregor, HJ; Nevell, TG; Mason, T; Laight, D; Shute, JK

2013-01-01

Background and Purpose Airway inflammation in cystic fibrosis (CF) patients is characterized by accumulations of neutrophils in the airway and T cells in bronchial tissue, with activation of platelets in the circulation. CF patients are routinely treated with systemic or inhaled tobramycin for airway infection with Pseudomonas aeruginosa. Clinical trials have indicated an anti-inflammatory effect of tobramycin beyond its bactericidal activity. Here, we investigate the anti-inflammatory properties of tobramycin in vitro and consider if these relate to the ability of tobramycin to bind copper, which is elevated in blood and sputum in CF. Experimental Approach A copper–tobramycin complex was synthesized. The effect of tobramycin and copper–tobramycin on neutrophil activation and migration of T cells and neutrophils across human lung microvascular endothelial cells in response to thrombin-activated platelets were investigated in vitro. Tobramycin uptake was detected by immunocytochemistry. Intracellular reactive oxygen species were detected using the fluorescent indicator, 2′,7′-dichlorofluorescein diacetate (DCFDA). Neutrophil superoxide, hydrogen peroxide and neutrophil elastase activity were measured using specific substrates. Copper was measured using atomic absorption spectroscopy. Key Results Tobramycin and copper–tobramycin were taken up by endothelial cells via a heparan sulphate-dependent mechanism and significantly inhibited T-cell and neutrophil transendothelial migration respectively. Copper–tobramycin has intracellular and extracellular superoxide dismutase-like activity. Neutrophil elastase inhibition by α1-antitrypsin is enhanced in the presence of copper–tobramycin. Tobramycin and copper–tobramycin are equally effective anti-pseudomonal antibiotics. Conclusions and Implications Anti-inflammatory effects of tobramycin in vivo may relate to the spontaneous formation of a copper–tobramycin complex, implying that copper–tobramycin may

Fundamental understanding and practical challenges of anionic redox activity in Li-ion batteries

NASA Astrophysics Data System (ADS)

Assat, Gaurav; Tarascon, Jean-Marie

2018-05-01

Our increasing dependence on lithium-ion batteries for energy storage calls for continual improvements in the performance of their positive electrodes, which have so far relied solely on cationic redox of transition-metal ions for driving the electrochemical reactions. Great hopes have recently been placed on the emergence of anionic redox—a transformational approach for designing positive electrodes as it leads to a near-doubling of capacity. But questions have been raised about the fundamental origins of anionic redox and whether its full potential can be realized in applications. In this Review, we discuss the underlying science that triggers a reversible and stable anionic redox activity. Furthermore, we highlight its practical limitations and outline possible approaches for improving such materials and designing new ones. We also summarize their chances for market implementation in the face of the competing nickel-based layered cathodes that are prevalent today.

Comparative studies on extracts from Hericium erinaceus by different polarity reagents to gain higher antioxidant activities.

PubMed

Jiang, Shengjuan; Wang, Yuliang; Zhang, Xiaolong

2016-07-01

Hericium erinaceus (H. erinaceus) is a source of exogenous antioxidants that has been traditionally used in China for the prevention and treatment of oxidative stress-associated disease. In the present study, the bioactive compounds of H. erinaceus were extracted with the following eight representative reagents: n-Hexane, xylene, chloroform, anhydrous ether, ethyl acetate, acetone, anhydrous ethanol and distilled water. The in vitro antioxidant activities were also evaluated. All of the extracted compounds exhibited reducing power and scavenging activity against 1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion free radicals. In addition, the antioxidant capacities varied with the used chemical reagents and exhibited dose-dependent effects. Extracts from anhydrous ethanol, chloroform and acetone were capable of inhibiting lipid peroxidation. The anhydrous ethanol extracts were observed to have significant levels of antioxidant compounds since they had a strong reducing power, high scavenging rates against DPPH and superoxide anion-free radicals (>90%), and high inhibition rates on lipid peroxidation (>60%). The present study will provide reference data for the antioxidant applications of H. erinaceus in pharmaceutical use and disease prevention.

Comparative studies on extracts from Hericium erinaceus by different polarity reagents to gain higher antioxidant activities

PubMed Central

JIANG, SHENGJUAN; WANG, YULIANG; ZHANG, XIAOLONG

2016-01-01

Hericium erinaceus (H. erinaceus) is a source of exogenous antioxidants that has been traditionally used in China for the prevention and treatment of oxidative stress-associated disease. In the present study, the bioactive compounds of H. erinaceus were extracted with the following eight representative reagents: n-Hexane, xylene, chloroform, anhydrous ether, ethyl acetate, acetone, anhydrous ethanol and distilled water. The in vitro antioxidant activities were also evaluated. All of the extracted compounds exhibited reducing power and scavenging activity against 1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion free radicals. In addition, the antioxidant capacities varied with the used chemical reagents and exhibited dose-dependent effects. Extracts from anhydrous ethanol, chloroform and acetone were capable of inhibiting lipid peroxidation. The anhydrous ethanol extracts were observed to have significant levels of antioxidant compounds since they had a strong reducing power, high scavenging rates against DPPH and superoxide anion-free radicals (>90%), and high inhibition rates on lipid peroxidation (>60%). The present study will provide reference data for the antioxidant applications of H. erinaceus in pharmaceutical use and disease prevention. PMID:27347087

Anti-inflammatory effects of secondary metabolites of marine Pseudomonas sp. in human neutrophils are through inhibiting P38 MAPK, JNK, and calcium pathways.

PubMed

Yang, Shun-Chin; Sung, Ping-Jyun; Lin, Chwan-Fwu; Kuo, Jimmy; Chen, Chun-Yu; Hwang, Tsong-Long

2014-01-01

Activated neutrophils play a significant role in the pathogenesis of many inflammatory diseases. The metabolites of marine microorganisms are increasingly employed as sources for developing new drugs; however, very few marine drugs have been studied in human neutrophils. Herein, we showed that secondary metabolites of marine Pseudomonas sp. (N11) significantly inhibited superoxide anion generation and elastase release in formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP)-activated human neutrophils, with IC50 values of 0.67±0.38 µg/ml and 0.84±0.12 µg/ml, respectively. In cell-free systems, neither superoxide anion-scavenging effect nor inhibition of elastase activity was associated with the suppressive effects of N11. N11 inhibited the phosphorylation of p38 MAP kinase and JNK, but not Erk and Akt, in FMLP-induced human neutrophils. Also, N11 dose-dependently attenuated the transient elevation of intracellular calcium concentration in activated neutrophils. In contrast, N11 failed to alter phorbol myristate acetate-induced superoxide anion generation, and the inhibitory effects of N11 were not reversed by protein kinase A inhibitor. In conclusion, the anti-inflammatory effects of N11 on superoxide anion generation and elastase release in activated human neutrophils are through inhibiting p38 MAP kinase, JNK, and calcium pathways. Our results suggest that N11 has the potential to be developed to treat neutrophil-mediated inflammatory diseases.

NADPH oxidase 4-derived superoxide mediates flow-stimulated NKCC2 activity in thick ascending limbs.

PubMed

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.

Superoxide Dismutase

PubMed Central

Lee, Edward H.; Bennett, Jesse H.

1982-01-01

An experimental chemical N-[2-(2-oxo-1-imidazolidinyl)ethyl]-N′-phenylurea (EDU), is an effective protectant against acute and chronic foliar injury due to ozone (03) when sprayed on intact leaves or supplied to the plants through soil application. An 03-sensitive snap bean cultivar (Phaseolus vulgaris L. `Bush Blue Lake 290') was systemically treated with EDU (0, 25, 50, and 100 milligrams per 15-centimeter diameter pot) to determine if EDU-induced or activated protective oxyradical and peroxyl scavenging enzymes. EDU-enhanced tolerance to O3 injury always correlated with increases in superoxide dismutase (SOD) and catalase activities in the leaves. Peroxidase levels correlated more closely with foliar injury. Greater SOD levels in young leves compared to older leaves were associated with lower ozone sensitivities in these tissues. Polyacrylamide slab gel electrophoresis separations and specific determinations of SOD activity showed that EDU-treated plants possessed markedly greater SOD activity than non-treated plants. Tolerant plant tissues may have enhanced enzyme scavenging capabilities for the protection against toxic oxyradicals. Experimental confirmation for the oxyradical theory for O3 phytotoxicity and SOD involvement in the detoxification process are presented. Images PMID:16662420

Constraints on superoxide mediated formation of manganese oxides

PubMed Central

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

2013-01-01

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

Effects of redox-active interlayer anions on the oxygen evolution reactivity of NiFe-layered double hydroxide nanosheets

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

Zhou, Daojin; Cai, Zhao; Bi, Yongmin

Nickel-iron layered double hydroxide (NiFe-LDH) nanosheets have shown optimal oxygen evolution reaction (OER) performance; however, the role of the intercalated ions in the OER activity remains unclear. In this work, we show that the activity of the NiFe-LDHs can be tailored by the intercalated anions with different redox potentials. The intercalation of anions with low redox potential (high reducing ability), such as hypophosphites, leads to NiFe-LDHs with low OER overpotential of 240 mV and a small Tafel slope of 36.9 mV/dec, whereas NiFe-LDHs intercalated with anions of high redox potential (low reducing ability), such as fluorion, show a high overpotentialmore » of 370 mV and a Tafel slope of 80.8 mV/dec. The OER activity shows a surprising linear correlation with the standard redox potential. Density functional theory calculations and X-ray photoelectron spectroscopy analysis indicate that the intercalated anions alter the electronic structure of metal atoms which exposed at the surface. Anions with low standard redox potential and strong reducing ability transfer more electrons to the hydroxide layers. Finally, this increases the electron density of the surface metal sites and stabilizes their high-valence states, whose formation is known as the critical step prior to the OER process.« less

Effects of redox-active interlayer anions on the oxygen evolution reactivity of NiFe-layered double hydroxide nanosheets

DOE PAGES

Zhou, Daojin; Cai, Zhao; Bi, Yongmin; ...

2018-02-02

Nickel-iron layered double hydroxide (NiFe-LDH) nanosheets have shown optimal oxygen evolution reaction (OER) performance; however, the role of the intercalated ions in the OER activity remains unclear. In this work, we show that the activity of the NiFe-LDHs can be tailored by the intercalated anions with different redox potentials. The intercalation of anions with low redox potential (high reducing ability), such as hypophosphites, leads to NiFe-LDHs with low OER overpotential of 240 mV and a small Tafel slope of 36.9 mV/dec, whereas NiFe-LDHs intercalated with anions of high redox potential (low reducing ability), such as fluorion, show a high overpotentialmore » of 370 mV and a Tafel slope of 80.8 mV/dec. The OER activity shows a surprising linear correlation with the standard redox potential. Density functional theory calculations and X-ray photoelectron spectroscopy analysis indicate that the intercalated anions alter the electronic structure of metal atoms which exposed at the surface. Anions with low standard redox potential and strong reducing ability transfer more electrons to the hydroxide layers. Finally, this increases the electron density of the surface metal sites and stabilizes their high-valence states, whose formation is known as the critical step prior to the OER process.« less

Specific anion effects on copper surface through electrochemical treatment: Enhanced photoelectrochemical CO2 reduction activity of derived nanostructures induced by chaotropic anions

NASA Astrophysics Data System (ADS)

Navaee, Aso; Salimi, Abdollah

2018-05-01

Copper derivatives are the most prominent CO2 reduction electrocatalyst. Herein, the metallic copper has been electrochemically treated with some of common ionic salts such as N3bar, HPO2bar, S2bar, Fbar, Clbar, Brbar and Ibar based on the dissolution of a metallic working electrode in an aqueous solution to derive the surface roughness incorporated with nanostructures. Diverse surface morphology can be obtained when the ionic radii of anions are changed. Surface study reveals various roughness shapes based on the size and polarity of the anions, where the ions with higher ionic radii have higher impact on the Cu surface. In comparison, polyatomic oxyanion such as HPO2bar even with large ionic radii do not have enough strength to create the surface roughness than that of oxygen-free anions with large ionic radii. The photoelectrochemical behavior of the modified surfaces toward CO2 reduction is studied at a wide potential window in bicarbonate aqueous solution. Based on our investigations, treated surfaces by Ibar, Clbar and S2bargive a more surface roughness, while Ibar and N3bar offer higher catalytic activity toward CO2 reduction due to possible complexing ability of these anions with Cu cations, followed by formation of the co-catalyst semiconductor and facilitate electron transfer. This methodology can be applied to investigate the effect of ions on transition metals along with obtaining different surface morphologies tailored to different applications.

Erythrocyte CuZn superoxide dismutase activity is decreased in iron-deficiency anemia.

PubMed

Olivares, M; Araya, M; Pizarro, F; Letelier, A

2006-09-01

Iron and copper are essential microminerals that are intimately related. The present study was performed to determine the effect of iron-deficiency anemia (IDA) and treatment with iron on laboratory indicators of copper status. Hemoglobin, mean corpuscular volume erythrocyte Zn protoporphyrin, serum ferritin, serum copper, serum ceruloplasmin, and erythrocyte CuZn-superoxide dismutase (SOD) activity were studied in 12 adult women with IDA before and after iron treatment for 60-90 d (100 mg/d Fe, as ferric polymaltose) and in 27 women with normal iron status. Prior to treatment with iron, serum copper and ceruloplasmin were not different between the groups and treatment with iron did not affect these measures. IDA women, before and after treatment with iron, presented a 2.9- and 2-fold decrease in erythrocyte CuZn-SOD activity compared to women with normal iron status (p < 0.001). Treatment with iron increased erythrocyte CuZn-SOD activity of the IDA group; however, this change was not statistically significant. In conclusion, CuZn-SOD activity is decreased in IDA. Measurement of this enzyme activity is not useful for evaluating copper nutrition in iron-deficient subjects.

Spectroscopic studies on the antioxidant activity of ellagic acid

NASA Astrophysics Data System (ADS)

Kilic, Ismail; Yeşiloğlu, Yeşim; Bayrak, Yüksel

2014-09-01

Ellagic acid (EA, C14H6O8) is a natural dietary polyphenol whose benefits in a variety of diseases shown in epidemiological and experimental studies involve anti-inflammation, anti-proliferation, anti-angiogenesis, anticarcinogenesis and anti-oxidation properties. In vitro radical scavenging and antioxidant capacity of EA were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. EA inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-tocopherol and ascorbic acid displayed 69.8%, 66.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, EA had an effective DPPH• scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that EA can be used in the pharmacological, food industry and medicine because of these properties.

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

PubMed

Yoshida, T; Tanaka, M; Okamoto, K

2001-01-05

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

Hypochlorite and superoxide radicals can act synergistically to induce fragmentation of hyaluronan and chondroitin sulphates

PubMed Central

2004-01-01

Activated phagocytes release the haem enzyme MPO (myeloperoxidase) and also generate superoxide radicals (O2•−), and hence H2O2, via an oxidative burst. Reaction of MPO with H2O2 in the presence of chloride ions generates HOCl (the physiological mixture of hypochlorous acid and its anion present at pH 7.4). Exposure of glycosaminoglycans to a MPO–H2O2–Cl− system or reagent HOCl generates long-lived chloramides [R-NCl-C(O)-R′] derived from the glycosamine N-acetyl functions. Decomposition of these species by transition metal ions gives polymer-derived amidyl (nitrogen-centred) radicals [R-N•-C(O)-R′], polymer-derived carbon-centred radicals and site-specific strand scission. In the present study, we have shown that exposure of glycosaminoglycan chloramides to O2•− also promotes chloramide decomposition and glycosaminoglycan fragmentation. These processes are inhibited by superoxide dismutase, metal ion chelators and the metal ion-binding protein BSA, consistent with chloramide decomposition and polymer fragmentation occurring via O2•−-dependent one-electron reduction, possibly catalysed by trace metal ions. Polymer fragmentation induced by O2•− [generated by the superoxide thermal source 1, di-(4-carboxybenzyl)hyponitrite] was demonstrated to be entirely chloramide dependent as no fragmentation occurred with the native polymers or when the chloramides were quenched by prior treatment with methionine. EPR spin-trapping experiments using 5,5-dimethyl1-pyrroline-N-oxide and 2-methyl-2-nitrosopropane have provided evidence for both O2•− and polymer-derived carbon-centred radicals as intermediates. The results obtained are consistent with a mechanism involving one-electron reduction of the chloramides to yield polymer-derived amidyl radicals, which subsequently undergo intramolecular hydrogen atom abstraction reactions to give carbon-centred radicals. The latter undergo fragmentation reactions in a site-specific manner. This synergistic

Characterization and antioxidant activities of marine pepsin soluble collagen from the skin of yellow goosefish Lophius litulon

NASA Astrophysics Data System (ADS)

Zheng, Bin; Xiang, Xingwei; Zhou, Yufang; Yang, Huicheng; Luo, Hongyu; Liao, Miaofei; Wen, Zhengshun

2017-05-01

Characteristics and antioxidant activities of pepsin-soluble collagen (PSC) from yellow goosefish ( Lophius litulon) skins were investigated. PSC was characterized as a type I collagen, and its imino acid content was 193 residues/1 000 residues. PSC's denaturation temperature was 17.56°C and Fourier transform infrared spectra confirmed the presence of triple helices. Solubility analysis showed good solubility at acidic pH (1-6) or low NaCl concentrations (≤2%). PSC showed scavenging activity against hydroxyl radicals and superoxide anions in a concentration-dependent manner. Furthermore, PSC could protect D-galactose-induced skin aging by significantly controlling malondialdehyde formation and improving the activity of superoxide dismutase, glutathione peroxidase, catalase, glutathione, and hydroxyproline. PSC may be a promising antioxidant in appropriate applications.

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

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

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

1989-03-01

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

Spectroscopic studies on the antioxidant activity of p-coumaric acid.

PubMed

Kiliç, Ismail; Yeşiloğlu, Yeşim

2013-11-01

p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe(2+)) chelating activity and ferric ions (Fe(3+)) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPH scavenging, ABTS(+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power and ferrous ions (Fe(2+)) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties. Copyright © 2013 Elsevier B.V. All rights reserved.

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

PubMed Central

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

1996-01-01

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

Influence of anionic surface-active agents on the uptake of heavy metals by water hyacinth (Eichhornia crassipes)

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

Muramoto, S.; Oki, Y.

1984-10-01

In a previous paper, the ability of water hyacinth to remove toxic heavy metals, cadmium, lead, and mercury, from a metal-containing solution was reported. However, information on the effects of surface-active agents on the metal uptake from waste water by water hyacinth is insufficient. Surface-active agents including anionic detergents have been found in lake, ponds, and rivers polluted by waste from industry and municipal sewage treatment plants. The present study examines the uptake of cadmium or nickel in the presence of the anionic detergent sodium dedecyl sulfate.

Protective activity of hamamelitannin on cell damage of murine skin fibroblasts induced by UVB irradiation.

PubMed

Masaki, H; Atsumi, T; Sakurai, H

1995-07-01

The protective activities of hamamelitannin (2',5-di-O-galloyl-hamamelose) in Hamamelis virginiana L. and its related compound, gallic acid, on damaged murine skin fibroblasts induced by UVB irradiation were investigated. In order to exclude the UV absorbing effect of the compounds, the protection study was performed such that the fibroblasts were pretreated with hamamelitannin or gallic acid for 24 h before UVB irradiation. At 200 microM concentration, hamamelitannin gave the higher survival of 72.6 +/- 0.4% in comparison with that of gallic acid (35.5 +/- 1.0%), while UVB absorbers such as 2-ethylhexyl p-methoxycinnamate and hexylbenzoate did not show such protection. The scavenging activities of hamamelitannin and gallic acid against active oxygens such as superoxide anion radicals, hydroxyl radicals and singlet oxygens were evaluated using electron spin resonance (ESR-spin trapping method). Hamamelitannin and gallic acid showed potent scavenging activities against all active oxygens tested. Furthermore, the association of hamamelitannin to fibroblasts was examined by comparing it with that of gallic acid, and the following results were obtained: (1) hamamelitannin reduces the reaction rate of liposome entrapped-nitroblue tetrazolium (NBT) with external superoxide anions, and (2) several glycosides associate with fibroblasts. From these results, it was concluded that hamamelitannin protects murine fibroblasts against external active oxygens by associating with the cell surface through its sugar moiety.

Peroxisomal membrane manganese superoxide dismutase: characterization of the isozyme from watermelon (Citrullus lanatus Schrad.) cotyledons.

PubMed

Rodríguez-Serrano, María; Romero-Puertas, María C; Pastori, Gabriela M; Corpas, Francisco J; Sandalio, Luisa M; del Río, Luis A; Palma, José M

2007-01-01

In this work the manganese superoxide dismutase (Mn-SOD) bound to peroxisomal membranes of watermelon cotyledons (Citrullus lanatus Schrad.) was purified to homogeneity and some of its molecular properties were determined. The stepwise purification procedure consisted of ammonium sulphate fractionation, batch anion-exchange chromatography, and anion-exchange and gel-filtration column chromatography using a fast protein liquid chromatography system. Peroxisomal membrane Mn-SOD (perMn-SOD; EC 1.15.1.1) was purified 5600-fold with a yield of 2.6 mug of enzyme g(-1) of cotyledons, and had a specific activity of 480 U mg(-1) of protein. The native molecular mass determined for perMn-SOD was 108 000 Da, and it was composed of four equal subunits of 27 kDa, which indicates that perMn-SOD is a homotetramer. Ultraviolet and visible absorption spectra of the enzyme showed a shoulder at 275 nm and two absorption maxima at 448 nm and 555 nm, respectively. By isoelectric focusing, a pI of 5.75 was determined for perMn-SOD. In immunoblot assays, purified perMn-SOD was recognized by a polyclonal antibody against Mn-SOD from pea leaves, and the peroxisomal enzyme rapidly dissociated in the presence of dithiothreitol and SDS. The potential binding of the Mn-SOD isozyme to the peroxisomal membrane was confirmed by immunoelectron microscopy analysis. The properties of perMn-SOD and the mitMn-SOD are compared and the possible function in peroxisomal membranes of the peripheral protein Mn-SOD is discussed.

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

EPA Science Inventory

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

CATALASE AND SUPEROXIDE DISMUTASE OF ROOT-COLONIZING SAPROPHYTIC FLUORESCENT PSEUDOMONADS

EPA Science Inventory

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

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

PubMed

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

2015-01-01

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

An anionic defensin from Plutella xylostella with potential activity against Bacillus thuringiensis.

PubMed

Xu, X-X; Zhang, Y-Q; Freed, S; Yu, J; Gao, Y-F; Wang, S; Ouyang, L-N; Ju, W-Y; Jin, F-L

2016-12-01

Insect defensins, are cationic peptides that play an important role in immunity against microbial infection. In the present study, an anionic defensin from Plutella xylostella, (designated as PxDef) was first cloned and characterized. Amino acid sequence analysis showed that the mature peptide owned characteristic six-cysteine motifs with predicted isoelectric point of 5.57, indicating an anionic defensin. Quantitative real-time polymerase chain reaction analysis showed that PxDef was significantly induced in epidermis, fat body, midgut and hemocytes after injection of heat-inactivated Bacillus thuringiensis, while such an induction was delayed by the injection of live B. thuringiensis in the 4th instar larvae of P. xylostella. Knocking down the expression of nuclear transcription factor Dorsal in P. xylostella by RNA interference significantly decreased the mRNA level of PxDef, and increased the sensitivity of P. xylostella larvae to the infection by live B. thuringiensis. The purified recombinant mature peptide (PxDef) showed higher activity against Gram-positive bacteria, with the minimum inhibition concentrations of 1.6 and 2.6 µM against B. thuringiensis and Bacillus subtilis, respectively. To our knowledge, this is the first report about an anionic PxDef, which may play an important role in the immune system of P. xylostella against B. thuringiensis.

Mitogen-activated protein kinase kinase 5 (MKK5)-mediated signalling cascade regulates expression of iron superoxide dismutase gene in Arabidopsis under salinity stress

PubMed Central

Xing, Yu; Chen, Wei-hua; Jia, Wensuo; Zhang, Jianhua

2015-01-01

Superoxide dismutases (SODs) are involved in plant adaptive responses to biotic and abiotic stresses but the upstream signalling process that modulates their expression is not clear. Expression of two iron SODs, FSD2 and FSD3, was significantly increased in Arabidopsis in response to NaCl treatment but blocked in transgenic MKK5-RNAi plant, mkk5. Using an assay system for transient expression in protoplasts, it was found that mitogen-activated protein kinase kinase 5 (MKK5) was also activated in response to salt stress. Overexpression of MKK5 in wild-type plants enhanced their tolerance to salt treatments, while mkk5 mutant exhibited hypersensitivity to salt stress in germination on salt-containing media. Moreover, another kinase, MPK6, was also involved in the MKK5-mediated iron superoxide dismutase (FSD) signalling pathway in salt stress. The kinase activity of MPK6 was totally turned off in mkk5, whereas the activity of MPK3 was only partially blocked. MKK5 interacted with the MEKK1 protein that was also involved in the salt-induced FSD signalling pathway. These data suggest that salt-induced FSD2 and FSD3 expressions are influenced by MEKK1 via MKK5–MPK6-coupled signalling. This MAP kinase cascade (MEKK1, MKK5, and MPK6) mediates the salt-induced expression of iron superoxide dismutases. PMID:26136265

Sonochemiluminescence of lucigenin: Evidence of superoxide radical anion formation by ultrasonic irradiation

NASA Astrophysics Data System (ADS)

Matsuoka, Masanori; Takahashi, Fumiki; Asakura, Yoshiyuki; Jin, Jiye

2016-07-01

The sonochemiluminescence (SCL) behavior of lucigenin (Luc2+) has been studied in aqueous solutions irradiated with 500 kHz ultrasound. Compared with the SCL of a luminol system, a tremendously increased SCL intensity is observed from 50 µM Luc2+ aqueous solution (pH =11) when small amounts of coreactants such as 2-propanol coexist. It is shown that SCL intensity strongly depends on the presence of dissolved gases such as air, O2, N2, and Ar. The highest SCL intensity is obtained in an O2-saturated solution, indicating that molecular oxygen is required to generate SCL. Since SCL intensity is quenched completely in the presence of superoxide dismutase (SOD), an enzyme that can catalyze the disproportionation of O2 •-, the generation of O2 •- in the ultrasonic reaction field is important in the SCL of Luc2+. In this work, the evidence of O2 •- production is examined by a spectrofluorometric method using 2-(2-pyridyl)benzothiazoline as the fluorescent probe. The results indicate that the yield of O2 •- is markedly increased in the O2-saturated solutions when a small amount of 2-propanol coexists, which is consistent with the results of SCL measurements. 2-Propanol in the interfacial region of a cavitation bubble reacts with a hydroxyl radical (•OH) to form a 2-propanol radical, CH3C•(OH)CH3, which can subsequently react with dissolved oxygen to generate O2 •-. The most likely pathways for SCL as well as the spatial distribution of SCL in a microreactor are discussed in this study.

Identification of biomarkers for the antiangiogenic and antitumour activity of the superoxide dismutase 1 (SOD1) inhibitor tetrathiomolybdate (ATN-224)

PubMed Central

Doñate, F; Juarez, J C; Burnett, M E; Manuia, M M; Guan, X; Shaw, D E; Smith, E L P; Timucin, C; Braunstein, M J; Batuman, O A; Mazar, A P

2008-01-01

Tetrathiomolybdate (choline salt; ATN-224), a specific, high-affinity copper binder, is currently being evaluated in several phase II cancer trials. ATN-224 inhibits CuZn superoxide dismutase 1 (SOD1) leading to antiangiogenic and antitumour effects. The pharmacodynamics of tetrathiomolybdate has been followed by tracking ceruloplasmin (Cp), a biomarker for systemic copper. However, at least in mice, the inhibition of angiogenesis occurs before a measurable decrease in systemic copper is observed. Thus, the identification and characterisation of other biomarkers to follow the activity of ATN-224 in the clinic is of great interest. Here, we present the preclinical evaluation of two potential biomarkers for the activity of ATN-224: (i) SOD activity measurements in blood cells in mice and (ii) levels of endothelial progenitor cells (EPCs) in bonnet macaques treated with ATN-224. The superoxide dismutase activity in blood cells in mice is rapidly inhibited by ATN-224 treatment at doses at which angiogenesis is maximally inhibited. Furthermore, ATN-224 dosing in bonnet macaques causes a profound and reversible decrease in EPCs without significant toxicity. Thus, both SOD activity measurements and levels of EPCs may be useful biomarkers of the antiangiogenic activity of ATN-224 to be used in its clinical development. PMID:18253124

Anion-π Catalysts with Axial Chirality.

PubMed

Wang, Chao; Matile, Stefan

2017-09-04

The idea of anion-π catalysis is to stabilize anionic transition states by anion-π interactions on aromatic surfaces. For asymmetric anion-π catalysis, π-acidic surfaces have been surrounded with stereogenic centers. This manuscript introduces the first anion-π catalysts that operate with axial chirality. Bifunctional catalysts with tertiary amine bases next to π-acidic naphthalenediimide planes are equipped with a bulky aromatic substituent in the imide position to produce separable atropisomers. The addition of malonic acid half thioesters to enolate acceptors is used for evaluation. In the presence of a chiral axis, the selective acceleration of the disfavored but relevant enolate addition was much better than with point chirality, and enantioselectivity could be observed for the first time for this reaction with small-molecule anion-π catalysts. Enantioselectivity increased with the π acidity of the π surface, whereas the addition of stereogenic centers around the aromatic plane did not cause further improvements. These results identify axial chirality of the active aromatic plane generated by atropisomerism as an attractive strategy for asymmetric anion-π catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Anions coordinating anions: analysis of the interaction between anionic Keplerate nanocapsules and their anionic ligands.

PubMed

Melgar, Dolores; Bandeira, Nuno A G; Bonet Avalos, Josep; Bo, Carles

2017-02-15

Keplerates are a family of anionic metal oxide spherical capsules containing up to 132 metal atoms and some hundreds of oxygen atoms. These capsules holding a high negative charge of -12 coordinate both mono-anionic and di-anionic ligands thus increasing their charge up to -42, even up to -72, which is compensated by the corresponding counter-cations in the X-ray structures. We present an analysis of the relative importance of several energy terms of the coordinate bond between the capsule and ligands like carbonate, sulphate, sulphite, phosphinate, selenate, and a variety of carboxylates, of which the overriding component is contributed by solvation/de-solvation effects.

Superoxide-mediated decomposition of biological S-nitrosothiols.

PubMed

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

1998-03-13

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

High-dose ascorbic acid induces carcinostatic effects through hydrogen peroxide and superoxide anion radical generation-induced cell death and growth arrest in human tongue carcinoma cells.

PubMed

Ohwada, Ryouhei; Ozeki, Yu; Saitoh, Yasukazu

2017-01-01

High-dose ascorbic acid (AsA) treatment, known as pharmacological AsA, has been shown to exert carcinostatic effects in many types of cancer cells and in vivo tumour models. Although pharmacological AsA has potential as a complementary and alternative medicine for anticancer treatment, its effects on human tongue carcinoma have not yet been elucidated. In this study, we investigated the effect of AsA treatment on human tongue carcinoma HSC-4 cells compared with non-tumourigenic tongue epithelial dysplastic oral keratinocyte (DOK) cells. Our results show that treatment with 1 and 3 mM of AsA for 60 min preferentially inhibits the growth of human tongue carcinoma HSC-4 over DOK cells. Furthermore, AsA-induced effects were accompanied by increased intracellular oxidative stress and were repressed by treatment with a hydrogen peroxide (H 2 O 2 ) scavenger catalase and a superoxide anion radical (O 2 - ) scavenger, tempol. Time-lapse observation and thymidine analog EdU incorporation revealed that AsA treatment induces not only cell death but also suppression of DNA synthesis and cell growth. Moreover, the growth arrest was accompanied by abnormal cellular morphologies whereby cells extended dendrite-like pseudopodia. Taken together, our results demonstrate that AsA treatment can induce carcinostatic effects through induction of cell death, growth arrest, and morphological changes mediated by H 2 O 2 and O 2 - generation. These findings suggest that high-dose AsA treatment represents an effective treatment for tongue cancer as well as for other types of cancer cells.

Human Manganese Superoxide Dismutase Tyrosine 34 Contribution to Structure and Catalysis

PubMed Central

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

2009-01-01

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

In vitro antioxidant and antiproliferative activities of selenium-containing phycocyanin from selenium-enriched Spirulina platensis.

PubMed

Chen, Tianfeng; Wong, Yum-Shing

2008-06-25

Both selenium and phycocyanin have been reported to show potent cancer chemopreventive activities. In this study, we investigated the in vitro antioxidant and antiproliferative activities of selenium-containing phycocyanin (Se-PC) purified from selenium-enriched Spirulina platensis. The antioxidant activity of Se-PC was evaluated by using four different free radical scavenging assays, namely, the 2,2'-azinobis-3-ethylbenzothiazolin-6-sulfonic acid (ABTS) assay, 1,1-diphenyl-2-picryhydrazyl (DPPH) assay, superoxide anion scavenging assay, and erythrocyte hemolysis assay. The results indicated that Se-PC exhibited stronger antioxidant activity than phycocyanin by scavenging ABTS, DPPH, superoxide anion, and 2,2'-azobis-(2-amidinopropane)dihydrochloride free radicals. Se-PC also showed dose-dependent protective effects on erythrocytes against H 2O 2-induced oxidative DNA damage as evaluated by the Comet assay. Moreover, Se-PC was identified as a potent antiproliferative agent against human melanoma A375 cells and human breast adenocarcinoma MCF-7 cells. Induction of apoptosis in both A375 and MCF-7 cells by Se-PC was evidenced by accumulation of sub-G1 cell populations, DNA fragmentation, and nuclear condensation. Further investigation on intracellular mechanisms indicated that depletion of mitochondrial membrane potential (DeltaPsi m) was involved in Se-PC-induced cell apoptosis. Our findings suggest that Se-PC is a promising organic Se species with potential applications in cancer chemoprevention.

Biological activities and chemical composition of lichens from Serbia

PubMed Central

Kosanic, Marijana; Rankovic, Branislav; Stanojkovic, Tatjana; Vasiljevic, Perica; Manojlovic, Nedeljko

2014-01-01

The aim of this study is to investigate chemical composition of acetone extracts of the lichens Parmelia arseneana and Acarospora fuscata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts and gyrophoric acid isolated from A. fuscata. The HPLC-UV method was used for the identification of secondary metabolites. Stictic acid, norstictic acid, gyrophoric acid, usnic acid, atranorin and chloroatranorin were identified in the A. fuscata. In P. arseneana, we detected stictic acid, norstictic acid, usnic acid and atranorin, while gyrophoric acid was not identified. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on DPPH and superoxide anion radicals, reducing the power of samples and determination of total phenolic compounds in extracts. As a result of the study, gyrophoric acid was found to have the largest DPPH radical scavenging activity with an IC50 value of 105.75 µg/ml. Moreover, the tested samples had an effective superoxide anion radical scavenging and reducing power. The total content of phenol in extracts was determined as pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was also gyrophoric acid, with minimum inhibitory concentration values ranging from 0.019 to 1.25 mg/ml. Anticancer activity was tested against LS174 (human colon carcinoma cell line), A549 (human lung carcinoma cell line), Fem-x (malignant melanoma cell line), and a chronic myelogeneous leukaemia K562 cell line using the MTT method. Extract of P. arseneana expressed the strongest anticancer activity against all cell lines with IC50 values ranging from 11.61 to 47.06 µg/ml. PMID:26417336

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

PubMed Central

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

2010-01-01

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

Seasonal superoxide overproduction and endothelial activation in guinea-pig heart; seasonal oxidative stress in rats and humans.

PubMed

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.

GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters.

PubMed

Ramesh, Sunita A; Tyerman, Stephen D; Xu, Bo; Bose, Jayakumar; Kaur, Satwinder; Conn, Vanessa; Domingos, Patricia; Ullah, Sana; Wege, Stefanie; Shabala, Sergey; Feijó, José A; Ryan, Peter R; Gilliham, Matthew; Gillham, Matthew

2015-07-29

The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms.

GABA signalling modulates plant growth by directly regulating the activity of plant-specific anion transporters

PubMed Central

Ramesh, Sunita A.; Tyerman, Stephen D.; Xu, Bo; Bose, Jayakumar; Kaur, Satwinder; Conn, Vanessa; Domingos, Patricia; Ullah, Sana; Wege, Stefanie; Shabala, Sergey; Feijó, José A.; Ryan, Peter R.; Gillham, Matthew

2015-01-01

The non-protein amino acid, gamma-aminobutyric acid (GABA) rapidly accumulates in plant tissues in response to biotic and abiotic stress, and regulates plant growth. Until now it was not known whether GABA exerts its effects in plants through the regulation of carbon metabolism or via an unidentified signalling pathway. Here, we demonstrate that anion flux through plant aluminium-activated malate transporter (ALMT) proteins is activated by anions and negatively regulated by GABA. Site-directed mutagenesis of selected amino acids within ALMT proteins abolishes GABA efficacy but does not alter other transport properties. GABA modulation of ALMT activity results in altered root growth and altered root tolerance to alkaline pH, acid pH and aluminium ions. We propose that GABA exerts its multiple physiological effects in plants via ALMT, including the regulation of pollen tube and root growth, and that GABA can finally be considered a legitimate signalling molecule in both the plant and animal kingdoms. PMID:26219411

Identification of the copper-zinc superoxide dismutase activity in Mycoplasma hyopneumoniae.

PubMed

Chen, J R; Weng, C N; Ho, T Y; Cheng, I C; Lai, S S

2000-05-11

Copper-zinc superoxide dismutase (Cu/ZnSOD), a key enzyme in defense against toxic oxygen-free radicals, is widespread in eukaryotes and several species of gram-negative bacteria. The presence of this enzyme in Mycoplasma hyopneumoniae (M. hyopneumoniae), the primary pathogen of mycoplasmal pneumonia in pigs, was examined since the polyclonal antibody against bovine Cu/ZnSOD was dominantly cross-reactive with the M. hyopneumoniae Cu/ZnSOD from whole cellular proteins. In situ activity staining on SDS-PAGE showed that the molecular mass of M. hyopneumoniae Cu/ZnSOD in reducing form was approximately 17kDa. The presence of Cu and Zn ions at the active site of the enzyme was confirmed on the basis of inhibition by KCN and by H(2)O(2). The activity of M. hyopneumoniae Cu/ZnSOD on both SDS- and native-polyacrylamide gels was completely inhibited by 2mM KCN and the gels showed no iron-containing SOD (FeSOD) or manganese-containing SOD (MnSOD) in the crude extracts. The activity of M. hyopneumoniae Cu/ZnSOD in crude extract was 70units/mg protein and was 55% inhibited by 5mM KCN and 56% inactivated by 40mM H(2)O(2). This enzyme was growth-stage dependent and evidenced markedly higher production during the early log phase. Different expression levels of Cu/ZnSOD activity in field isolates were also detected. Taken together, the presence of Cu/ZnSOD in M. hyopneumoniae was identified for the first time.

Perchlorate adsorption and desorption on activated carbon and anion exchange resin.

PubMed

Yoon, In-Ho; Meng, Xiaoguang; Wang, Chao; Kim, Kyoung-Woong; Bang, Sunbaek; Choe, Eunyoung; Lippincott, Lee

2009-05-15

The mechanisms of perchlorate adsorption on activated carbon (AC) and anion exchange resin (SR-7 resin) were investigated using Raman, FTIR, and zeta potential analyses. Batch adsorption and desorption results demonstrated that the adsorption of perchlorate by AC and SR-7 resin was reversible. The reversibility of perchlorate adsorption by the resin was also proved by column regeneration test. Solution pH significantly affected perchlorate adsorption and the zeta potential of AC, while it did not influence perchlorate adsorption and the zeta potential of resin. Zeta potential measurements showed that perchlorate was adsorbed on the negatively charged AC surface. Raman spectra indicated the adsorption resulted in an obvious position shift of the perchlorate peak, suggesting that perchlorate was associated with functional groups on AC at neutral pH through interactions stronger than electrostatic interaction. The adsorbed perchlorate on the resin exhibited a Raman peak at similar position as the aqueous perchlorate, indicating that perchlorate was adsorbed on the resin through electrostatic attraction between the anion and positively charged surface sites.

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

PubMed

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

2017-08-01

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

Metabolic control may influence the increased superoxide generation in diabetic serum.

PubMed

Ceriello, A; Giugliano, D; Quatraro, A; Dello Russo, P; Lefèbvre, P J

1991-07-01

Superoxide anion (O2-) generation in serum from 10 Type 1 diabetic patients and 10 normal subjects was measured ex vivo. The amount of O2- production was significantly increased in diabetic serum 0.41 +/- 0.04 (+/- SD) vs 0.14 +/- 0.04 mumol l-1 min-1, p less than 0.001) and correlated with fasting plasma glucose and glycosylated protein levels in both diabetic (r = 0.72, p less than 0.01, and r = 0.62, p less than 0.05) and normal r = 0.75, p less than 0.01 and r = 0.64, p less than 0.05) subjects. Improved metabolic control in the diabetic patients was associated with a reduction of serum O2- production (0.28 +/- 0.06 mumol l-1 min-1, p less than 0.01), but the correlation between O2- levels and fasting plasma glucose and glycosylated protein concentrations was retained (r = 0.86 and r = 0.72, respectively, both p less than 0.01).

The preparation and antioxidant activity of the sulfanilamide derivatives of chitosan and chitosan sulfates.

PubMed

Zhong, Zhimei; Ji, Xia; Xing, Ronge; Liu, Song; Guo, Zhanyong; Chen, Xiaolin; Li, Pengcheng

2007-06-01

Chitosan (CS) and chitosan sulfates (CSS) with different molecular weight (Mw) were reacted with 4-acetamidobenzene sulfonyl chloride to obtain sulfanilamide derivatives of chitosan and chitosan sulfates (LSACS, HSACS, LSACSS, HSACSS). The preparation conditions such as different reaction time, temperature, solvent, and the molar ratio of reaction materials are discussed in this paper. Their structures were characterized by FTIR spectroscopy and elemental analyses. The antioxidant activities of the derivatives were investigated employing various established in vitro systems, such as hydroxyl-radical ((*)OH) superoxide anion (O2(*-)) scavenging and reducing power. All kinds of the compounds (HCS, LCS, HCSS, LCSS, HSACS, LSACS, HSACSS, LSACSS) showed stronger scavenging activity on hydroxyl radical than ascorbic acid (Vc). The inhibitory activities of the derivatives toward superoxide radical by the PMS-NADH system were obvious. The experiment showed that the superoxide radical scavenging effect of sulfanilamide derivatives of chitosan and chitosan sulfates was stronger than that of original CS and CSS. All of the derivatives were efficient in the reducing power. The results indicated that the sulfanilamide group were grafted on CS and CSS increased the reducing power of them obviously.

Quenching of Superoxide Radicals by Green Fluorescent Protein

PubMed Central

Bou-Abdallah, Fadi; Chasteen, N. Dennis; Lesser, Michael P.

2006-01-01

Green fluorescent protein (GFP) is a widely used in vivo molecular marker. These proteins are particularly resistant, and maintain function, under a variety of cellular conditions such as pH extremes and elevated temperatures. Green fluorescent proteins are also abundant in several groups of marine invertebrates including reef-forming corals. While molecular oxygen is required for the post-translational maturation of the protein, mature GFPs are found in corals where hyperoxia and reactive oxygen species (ROS) occur due to the photosynthetic activity of algal symbionts. In vitro spin trapping electron paramagnetic resonance and spectrophotometric assays of superoxide dismutase (SOD)-like enzyme activity show that wild type GFP from the hydromedusa, Aequorea victoria, quenches superoxide radicals (O2•−) and exhibits SOD-like activity by competing with cytochrome c for reaction with O2•−. When exposed to high amounts of O2•− the SOD-like activity and protein structure of GFP are altered without significant changes to the fluorescent properties of the protein. Because of the distribution of fluorescent proteins in both the epithelial and gastrodermal cells of reef-forming corals we propose that GFP, and possibly other fluorescent proteins, can provide supplementary antioxidant protection. PMID:17023114

[Oxygen and the superoxide anion. Modulation of NADPH oxidase?].

PubMed

Delbosc, S; Cristol, J P; Descomps, B; Chénard, J; Sirois, P

2001-01-01

Oxidative stress which results from an imbalance between oxidant production and antioxidant defense mechanisms can promote modifications of lipids, proteins and nucleic acids. This review focuses on the different pathways leading to Reactive Oxygen Species (ROS) production in particular on NADPH oxidase activation. This enzyme is localized in numerous cells including phagocytes and vascular cells and composed of membrane and cytosolic sub-units. The activation of the NADPH oxidase is largely involved in inflammation associated diseases such as asthma, Systemic Inflammatory Response Syndrome and aging associated diseases such as atherosclerosis and neurodeneratives diseases. The modulation of NADPH oxidase could be a way to limit or prevent the development of these diseases.

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

PubMed

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

2005-12-31

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

Efficient, non-toxic anion transport by synthetic carriers in cells and epithelia

NASA Astrophysics Data System (ADS)

Li, Hongyu; Valkenier, Hennie; Judd, Luke W.; Brotherhood, Peter R.; Hussain, Sabir; Cooper, James A.; Jurček, Ondřej; Sparkes, Hazel A.; Sheppard, David N.; Davis, Anthony P.

2016-01-01

Transmembrane anion transporters (anionophores) have potential for new modes of biological activity, including therapeutic applications. In particular they might replace the activity of defective anion channels in conditions such as cystic fibrosis. However, data on the biological effects of anionophores are scarce, and it remains uncertain whether such molecules are fundamentally toxic. Here, we report a biological study of an extensive series of powerful anion carriers. Fifteen anionophores were assayed in single cells by monitoring anion transport in real time through fluorescence emission from halide-sensitive yellow fluorescent protein. A bis-(p-nitrophenyl)ureidodecalin shows especially promising activity, including deliverability, potency and persistence. Electrophysiological tests show strong effects in epithelia, close to those of natural anion channels. Toxicity assays yield negative results in three cell lines, suggesting that promotion of anion transport may not be deleterious to cells. We therefore conclude that synthetic anion carriers are realistic candidates for further investigation as treatments for cystic fibrosis.

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

PubMed

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

2017-05-01

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

Supramolecular Chemistry of Selective Anion Recognition for Anions of Environmental Relevance

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

Bowman-James, Kristen

2004-12-01

This project have focuses on the basic chemical aspects of anion receptor design of functional pH independent systems, with the ultimate goal of targeting the selective binding of sulfate, as well as design of separations strategies for selective and efficient removal of targeted anions. Key findings include: (1) the first synthetic sulfate-selective anion-binding agents; (2) simple, structure-based methods for modifying the intrinsic anion selectivity of a given class of anion receptors; and (3) the first system capable of extracting sulfate anion from acidic, nitrate-containing aqueous media. Areas probed during the last funding period include: the design, synthesis, and physical andmore » structural characterization of receptors and investigation of anion and dual ion pair extraction using lipophilic amide receptors for anion binding. A new collaboration has been added to the project in addition to the one with Dr. Bruce Moyer at Oak Ridge National Laboratory, with Professor Jonathan Sessler at the University of Texas at Austin.« less

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

PubMed

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

2012-11-01

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

Glutarimide alkaloids and a terpenoid benzoquinone from Cordia globifera.

PubMed

Parks, Joshua; Gyeltshen, Thinley; Prachyawarakorn, Vilailak; Mahidol, Chulabhorn; Ruchirawat, Somsak; Kittakoop, Prasat

2010-05-28

Three new compounds, a meroterpene (2) having a cyclopropane moiety named globiferane and glutarimide alkaloids named cordiarimides A (3) and B (4), were isolated from the roots of Cordia globifera. Compounds 2-4 exhibited weak cytotoxic activity. Cordiarimide B (4) exhibited radical scavenging activity, as it inhibited superoxide anion radical formation in the xanthine/xanthine oxidase (XXO) assay, and also suppressed superoxide anion generation in differentiated HL-60 human promyelocytic leukemia cells when induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). This is the first report on the presence of glutarimide alkaloids in the genus Cordia.

Sono-activated persulfate oxidation of diclofenac: Degradation, kinetics, pathway and contribution of the different radicals involved.

PubMed

Monteagudo, J M; El-Taliawy, H; Durán, A; Caro, G; Bester, K

2018-06-20

Degradation of a diclofenac aqueous solution was performed using persulfate anions activated by ultrasound. The objective of this study was to analyze different parameters affecting the diclofenac (DCF) removal reaction by the ultrasonic persulfate (US/PS) process and to evaluate the role played by various intermediate oxidative species such as hydroxyl- and sulfate radicals, superoxide radical anion or singlet oxygen in the removal process as well as to determine a possible reaction pathway. The effects of pH, initial persulfate anion concentration, ultrasonic amplitude and temperature on DCF degradation were examined. Sulfate and hydroxyl radicals were involved in the main reaction pathway of diclofenac. Diclofenac amide and three hydroxy-diclofenac isomers (3´-hydroxy diclofenac, 4´-hydroxy diclofenac and 5-hydroxy diclofenac) were identified as reaction intermediates. Copyright © 2018 Elsevier B.V. All rights reserved.

The influence of insulin-dependent diabetes mellitus (IDDM) duration on superoxide anion and hydrogen peroxide production by polymorphonuclear neutrophils.

PubMed

Zozulińska, D A; Wierusz-Wysocka, B; Wysocki, H; Majchrzak, A E; Wykretowicz, A

1996-08-01

We address the question whether oxygen metabolism of polymorphonuclear neutrophils (PMN) is influenced by disease duration in patients with insulin-dependent diabetes mellitus (IDDM). PMN were isolated from patients with IDDM of various durations and from healthy controls. We measured PMN production of superoxide anions (O2-) by cytochrome c reduction (see Babior, B.M. et al. (1973) J. Clin. Invest. 52, 741-746) and PMN production of hydrogen peroxide (H2O2) by phenol red oxygenation (see Pick, E. (1980) J. Immunol. Methods 38, 161-169) in three groups of IDDM patients subdivided according to disease duration (group A: IDDM less that 10 years; group B: IDDM of 10-15 years; group C: IDDM of more than 15 years) and in control healthy subjects (group H). Unstimulated O2- production in all IDDM patients was not statistically different from control values (A: 4.3 +/- 0.4 nmol/10(6) PMN per 30 min, nmol/10(6) PMN per 30 min; C: 4.9 +/- 0.9 nmol/10(6) PMN per 30 min; and H: 3.5 +/- 0.2 nmol/10(6) PMN per 30 min, respectively). In contrast, stimulated O2- production was significantly lower in both patients with 10-15 years, and patients with more than 15 years, duration of IDDM than in controls (B: 25.7 +/- 2.5 nmol/10(6) PMN per 30 min; C: 21.1 +/- 3.4 nmol/10(6) PMN per 30 min and H: 42.2 +/- 1.1 nmol/10(6) PMN per 30 min, respectively) correlating with disease duration (r = -0.44, P < 0.033). The stimulated O2- production in patients with less than 10 years duration of IDDM (A: 35.7 +/- 1.9 nmol/10(6) PMN per 30 min) was slightly lower than in controls. H2O2 production of unstimulated PMN (A: 4.0 +/- 0.5 nmol/10(6) PMN per 30 min; B: 4.4 +/- 0.8 nmol/10(6) PMN per 30 min and C: 4.4 +/-1.0 nmol/10(6) PMN per 30 min, respectively) was much higher than those in controls. In contrast, stimulated H2O2 production did not differ statistically from the value noticed in healthy subjects. The results obtained might indicate that production of H2O2 by unstimulated cells is

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

PubMed Central

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

2002-01-01

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

Anion exchange membrane

DOEpatents

Verkade, John G; Wadhwa, Kuldeep; Kong, Xueqian; Schmidt-Rohr, Klaus

2013-05-07

An anion exchange membrane and fuel cell incorporating the anion exchange membrane are detailed in which proazaphosphatrane and azaphosphatrane cations are covalently bonded to a sulfonated fluoropolymer support along with anionic counterions. A positive charge is dispersed in the aforementioned cations which are buried in the support to reduce the cation-anion interactions and increase the mobility of hydroxide ions, for example, across the membrane. The anion exchange membrane has the ability to operate at high temperatures and in highly alkaline environments with high conductivity and low resistance.

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

PubMed

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

2005-08-01

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

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

PubMed Central

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

2005-01-01

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

Phytochemical screening and polyphenolic antioxidant activity of aqueous crude leaf extract of Helichrysum pedunculatum.

PubMed

Aiyegoro, Olayinka A; Okoh, Anthony I

2009-11-13

We evaluated the in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extract of Helichrysum pedunculatum. The scavenging activity on superoxide anions, DPPH, H₂O₂, NO and ABTS; and the reducing power were determined, as well as the flavonoid, proanthocyanidin and phenolic contents of the extract. The extract exhibited scavenging activity towards all radicals tested due to the presence of relatively high total phenol and flavonoids contents. Our findings suggest that H. pedunculatum is endowed with antioxidant phytochemicals and could serve as a base for future drugs.

Phytochemical Screening and Polyphenolic Antioxidant Activity of Aqueous Crude Leaf Extract of Helichrysum pedunculatum

PubMed Central

Aiyegoro, Olayinka A.; Okoh, Anthony I.

2009-01-01

We evaluated the in vitro antioxidant property and phytochemical constituents of the aqueous crude leaf extract of Helichrysum pedunculatum. The scavenging activity on superoxide anions, DPPH, H2O2, NO and ABTS; and the reducing power were determined, as well as the flavonoid, proanthocyanidin and phenolic contents of the extract. The extract exhibited scavenging activity towards all radicals tested due to the presence of relatively high total phenol and flavonoids contents. Our findings suggest that H. pedunculatum is endowed with antioxidant phytochemicals and could serve as a base for future drugs. PMID:20087473

Superoxide from NADPH oxidase upregulates type 5 phosphodiesterase in human vascular smooth muscle cells: inhibition with iloprost and NONOate.

PubMed

Muzaffar, S; Shukla, N; Bond, M; Sala-Newby, G B; Newby, A C; Angelini, G D; Jeremy, J Y

2008-11-01

To determine whether there is an association between vascular NADPH oxidase (NOX), superoxide, the small GTPase Rac(1) and PDE type 5 (PDE5) in human vascular smooth muscle cell (hVSMCs). hVSMCs were incubated with xanthine-xanthine oxidase (X-XO; a superoxide generating system) or the thromboxane A(2) analogue, U46619 (+/-superoxide dismutase (SOD) or apocynin) for 16 h. The expression of PDE5 and NOX-1 was assessed using Western blotting and superoxide measured. The role of Rac(1) in superoxide generation was assessed by overexpressing either the dominant-negative or constitutively active Rac isoforms. The effects of iloprost, DETA-NONOate and the Rho-kinase inhibitor, Y27632, on PDE5 and NOX-1 expression were also studied. Following 16 h incubation, U46619 and X-XO promoted the expression of PDE5 and NOX-1, an effect blocked by SOD or apocynin when co-incubated over the same time course. X-XO and U46619 both promoted the formation of superoxide. Overexpression of dominant-negative Rac(1) or addition of iloprost, DETA-NONOate or Y27632 completely blocked both superoxide release and PDE5 protein expression and activity. These data demonstrate that superoxide derived from NOX upregulates the expression of PDE5 in human VSMCs. As PDE5 hydrolyses cyclic GMP, this effect may blunt the vasculoprotective actions of NO.

Calcium-calmodulin does not alter the anion permeability of the mouse TMEM16A calcium-activated chloride channel

PubMed Central

Yu, Yawei; Kuan, Ai-Seon

2014-01-01

The transmembrane protein TMEM16A forms a Ca2+-activated Cl− channel that is permeable to many anions, including SCN−, I−, Br−, Cl−, and HCO3−, and has been implicated in various physiological functions. Indeed, controlling anion permeation through the TMEM16A channel pore may be critical in regulating the pH of exocrine fluids such as the pancreatic juice. The anion permeability of the TMEM16A channel pore has recently been reported to be modulated by Ca2+-calmodulin (CaCaM), such that the pore of the CaCaM-bound channel shows a reduced ability to discriminate between anions as measured by a shift of the reversal potential under bi-ionic conditions. Here, using a mouse TMEM16A clone that contains the two previously identified putative CaM-binding motifs, we were unable to demonstrate such CaCaM-dependent changes in the bi-ionic potential. We confirmed the activity of CaCaM used in our study by showing CaCaM modulation of the olfactory cyclic nucleotide–gated channel. We suspect that the different bi-ionic potentials that were obtained previously from whole-cell recordings in low and high intracellular [Ca2+] may result from different degrees of bi-ionic potential shift secondary to a series resistance problem, an ion accumulation effect, or both. PMID:24981232

Biological activities of two macroalgae from Adriatic coast of Montenegro

PubMed Central

Kosanić, Marijana; Ranković, Branislav; Stanojković, Tatjana

2014-01-01

In the present investigation the acetone extracts of macroalgae Ulva lactuca and Enteromorpha intestinalis were tested for antioxidant, antimicrobial and cytotoxic potential. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on DPPH and superoxide anion radicals, reducing the power of samples and determination of total phenolic and flavonoid compounds in extracts. As a result of the study, U. lactuca extract was found to have a better free radical scavenging activity (IC50 = 623.58 μg/ml) than E. intestinalis extract (IC50 = 732.12 μg/ml). Moreover, the tested extracts had effective ferric reducing power and superoxide anion radical scavenging. The total content of phenol in extracts of U. lactuca and E. intestinalis was 58.15 and 40.68 μg PE/mg, while concentrations of flavonoids were 39.58 and 21.74 μg RE/mg, respectively. Furthermore, among the tested species, extracts of U. lactuca showed a better antimicrobial activity with minimum inhibitory concentration values ranging from 0.156 to 5 mg/ml, but it was relatively weak in comparison with standard antibiotics. Bacillus mycoides and Bacillus subtilis were the most susceptible to the tested extracts. Contrary to this Aspergillus flavus, Aspergillus fumigatus and Penicillium purpurescens were the most resistant. Finally, cytotoxic activity of tested extracts was evaluated on four human cancer cell lines. Extract of E. intestinalis expressed the stronger cytotoxic activity towards all tested cell lines with IC50 values ranging from 74.73 to 155.39 μg/ml. PMID:26150743

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

PubMed

Brand, Martin D

2016-11-01

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

Effect of Trasina, an Ayurvedic herbal formulation, on pancreatic islet superoxide dismutase activity in hyperglycaemic rats.

PubMed

Bhattacharya, S K; Satyan, K S; Chakrabarti, A

1997-03-01

Diabetes mellitus was induced in male CF strain rats by streptozotocin (STZ) and hyperglycaemia and superoxide dismutase (SOD) activity of pancreatic islet cells was assessed on days 7, 14, 21 and 28. STZ induced significant hyperglycaemia and a concomitant decrease in islet cell SOD activity. Transina (TR), an Ayurvedic herbal formulation comprising of Withania somnifera, Tinospora cordifolia, Eclipta alba, Ocimum sanctum, Picrorrhiza kurroa and shilajit, had little per se effect on blood sugar concentrations and islet SOD activity in euglycaemic rats, in the doses of 100 and 200 mg/kg, p.o. administered once daily for 28 days. However, these doses of TR induced a dose- related decrease in STZ hyperglycaemia and attenuation of STZ induced decrease in islet SOD activity. The results indicate that the earlier reported anti-hyperglycaemic effect of TR may be due to pancreatic islet free radical scavenging activity, the hyperglycaemic activity of STZ being the consequence of decrease in islet SOD activity leading to the accumulation of degenerative oxidative free radicals in islet beta-cells.

Activity of superoxide dismutase in Galleria mellonella larvae infected with entomopathogenic nematodes Steinernema affinis and S. feltiae.

PubMed

Zółtowska, Krystyna; Grochla, Paulina; Łopieńska-Biernat, Elzbieta

2006-01-01

The influence of infection with two species of entomopathogenic nematodes of Steinernematidae family on the activity of superoxide dismutase (SOD) of the host was studied. Last instar larvae of Galleria mellonella were experimentally infected with Steinernema affinis and S. feltiae at 20 invasive juveniles per insect. At 6, 12, 18, 24 and 36 h after infection activity of SOD was determined in extracts from infected and control insects. The activity of SOD decreased gradually in the controls during the experiment. The activity of enzyme was 2-4-times higher in insects from both infected groups than in the control. During the first 12 h of infection the activity of SOD in insects infected with S. feltiae was higher than in those infected with S. affinis, then the activity of enzyme in the insects of both infected groups stayed at a similar level. A significant decrease of SOD activity in infected was recorded in second day of the infection.

Purification and properties of Cu-Zn superoxide dismutase extracted from Brucella abortus strain 19

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

Tabatabai, L.B.

Recent work showed that a recombinant 20 kDa protein from Brucella abortus expressed in E. coli is a Cu-Zn superoxide dismutase (SOD). Western blot and ELISA results indicated that cattle with brucellosis have antibody to SOD. Here the authors report the purification and properties of the native B. abortus Cu-Zn SOD. SOD was extracted from methanol-killed Brucella abortus strain 19 with 0.1 M sodium citrate-1.0 M sodium chloride solution. The extract was dialyzed and protein precipitated by ammonium sulfate at 70-100% saturation was collected. The SOD was purified by HPLC anion exchange chromatography. SOD activity was assayed with a coupledmore » enzyme assay using xanthine oxidase-cytochrome C reduction assay. The authors determined that the Brucella SOD is present in two molecular forms both inhibitable with KCN with Ki's of 0.32 mM and 4.98 mM, respectively. No other form of SOD was identified in the extract. Polyclonal antibody to SOD and polyclonal antibody to SOD synthetic peptide residues 134-143 inhibited SOD activity by 50% and 13%, respectively. Both SOD and the synthetic peptide inhibited binding of anti-SOD antibody to SOD by 60% and 20%, respectively. Based on these results the SOD and its amphipathic peptide will be considered as candidates for the design of synthetic multiple peptide vaccines and diagnostic reagents for bovine brucellosis.« less

The decomposition of peroxynitrite to nitroxyl anion (NO−) and singlet oxygen in aqueous solution

PubMed Central

Khan, Ahsan Ullah; Kovacic, Dianne; Kolbanovskiy, Alexander; Desai, Mehul; Frenkel, Krystyna; Geacintov, Nicholas E.

2000-01-01

The mechanism of decomposition of peroxynitrite (OONO−) in aqueous sodium phosphate buffer solution at neutral pH was investigated. The OONO− was synthesized by directly reacting nitric oxide with superoxide anion at pH 13. The hypothesis was explored that OONO−, after protonation at pH 7.0 to HOONO, decomposes into 1O2 and HNO according to a spin-conserved unimolecular mechanism. Small aliquots of the concentrated alkaline OONO− solution were added to a buffer solution (final pH 7.0–7.2), and the formation of 1O2 and NO− in high yields was observed. The 1O2 generated was trapped as the transannular peroxide (DPAO2) of 9,10-diphenylanthracene (DPA) dissolved in carbon tetrachloride. The nitroxyl anion (NO−) formed from HNO (pKa 4.5) was trapped as nitrosylhemoglobin (HbNO) in an aqueous methemoglobin (MetHb) solution. In the presence of 25 mM sodium bicarbonate, which is known to accelerate the rate of decomposition of OONO−, the amount of singlet oxygen trapped was reduced by a factor of ≈2 whereas the yield of trapping of NO− by methemoglobin remained unaffected. Because NO3− is known to be the ultimate decomposition product of OONO−, these results suggest that the nitrate anion is not formed by a direct isomerization of OONO−, but by an indirect route originating from NO−. PMID:10716721

Understanding Anionic "Ligandless" Palladium Species in the Mizoroki-Heck Reaction.

PubMed

Schroeter, Felix; Strassner, Thomas

2018-05-07

The anionic complex [NBu 4 ][Pd(DMSO)Cl 3 ], as a "ligandless" system, was shown to be an active catalyst in the Mizoroki-Heck coupling of aryl chlorides in the absence of strongly σ-donating ligands. To investigate the experimentally observed influence of halides and the amount of water on the catalytic activity, we employed a combination of experiments and theoretical calculations. The presence of water was shown to be critical for the formation of the active palladium(0) species by oxidation of in situ generated tributylamine. Oxidative addition to an anionic palladium(0) species was found to be the rate-determining step of the catalytic cycle. For the ensuing steps, both neutral and anionic pathways were considered. It was shown that, in the absence of strongly σ-donating neutral ligands, chloride ions stabilize the catalytic intermediates. Therefore, an anionic pathway is preferred, which explains the need for tetrabutylammonium chloride as an additive. The study of the influence of bromide ions on the catalytic activity revealed that the strongly exergonic displacement of the neutral substrates by bromide ions lowers the catalytic activity.

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

NASA Technical Reports Server (NTRS)

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

1982-01-01

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

Superoxide from NADPH oxidase upregulates type 5 phosphodiesterase in human vascular smooth muscle cells: inhibition with iloprost and NONOate

PubMed Central

Muzaffar, S; Shukla, N; Bond, M; Sala-Newby, G B; Newby, A C; Angelini, G D; Jeremy, J Y

2008-01-01

Background and purpose: To determine whether there is an association between vascular NADPH oxidase (NOX), superoxide, the small GTPase Rac1 and PDE type 5 (PDE5) in human vascular smooth muscle cell (hVSMCs). Experimental approach: hVSMCs were incubated with xanthine–xanthine oxidase (X-XO; a superoxide generating system) or the thromboxane A2 analogue, U46619 (±superoxide dismutase (SOD) or apocynin) for 16 h. The expression of PDE5 and NOX-1 was assessed using Western blotting and superoxide measured. The role of Rac1 in superoxide generation was assessed by overexpressing either the dominant-negative or constitutively active Rac isoforms. The effects of iloprost, DETA-NONOate and the Rho-kinase inhibitor, Y27632, on PDE5 and NOX-1 expression were also studied. Key results: Following 16 h incubation, U46619 and X-XO promoted the expression of PDE5 and NOX-1, an effect blocked by SOD or apocynin when co-incubated over the same time course. X-XO and U46619 both promoted the formation of superoxide. Overexpression of dominant-negative Rac1 or addition of iloprost, DETA-NONOate or Y27632 completely blocked both superoxide release and PDE5 protein expression and activity. Conclusions and implications: These data demonstrate that superoxide derived from NOX upregulates the expression of PDE5 in human VSMCs. As PDE5 hydrolyses cyclic GMP, this effect may blunt the vasculoprotective actions of NO. PMID:18660830

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

PubMed

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

2017-05-01

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

Anti-inflammatory triterpenoids from the stems of Microtropis fokienensis.

PubMed

Chen, I-Hsiao; Du, Ying-Chi; Hwang, Tsong-Long; Chen, I-Fen; Lan, Yu-Hsuan; Yen, Hsin-Fu; Chang, Fang-Rong; Wu, Yang-Chang

2014-04-14

Three new ursane- and four new oleanane- type triterpenoids 1-7 were isolated, along with six known compounds 8-13, from the methanolic extract of Microtropis fokienensis. All structures were elucidated by mass and NMR spectroscopic methods. The isolates 4-10 and known compounds 14-17 that were previously isolated from this material were evaluated for anti-inflammatory activity based on effects against superoxide anion generation and elastase release by neutrophils in response to fMLP/CB. 11α,30-Dihydroxy-2,3-seco-olean-12-en-2,3-dioic anhydride (7) was the first triterpene anhydride from the genus of Microtropis to have the ring A expanded to a seven-membered ring; it showed significant anti-inflammatory activity against superoxide anion generation and elastase release. Unexpectedly, 30-hydroxy-2,3-seco-lup-20(29)-ene-2,3-dioic acid (17) showed the best effect against superoxide anion generation and elastase release with IC50 values of 0.06±0.01 and 1.03±0.35 µg/mL, respectively. Compound 17 had a dioic acid function, and compound 7 had an anhydride function modification in ring A; both showed promising activity in the target assays.

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

PubMed

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

2016-12-01

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

Effect of different processing methods on antioxidant activity of underutilized legumes, Entada scandens seed kernel and Canavalia gladiata seeds.

PubMed

Sasipriya, Gopalakrishnan; Siddhuraju, Perumal

2012-08-01

The present study is proposed to determine the antioxidant activity of raw and processed samples of underutilized legumes, Entada scandens seed kernel and Canavalia gladiata seeds. The indigenous processing methods like dry heating, autoclaving and soaking followed by autoclaving in different solutions (plain water, ash, sugar and sodium bicarbonate) were adopted to seed samples. All other processing methods than dry heat showed significant reduction in phenolics (2.9-63%), tannins (26-100%) and flavonoids (14-67%). However, in processed samples of E. scandens, the hydroxyl radical scavenging activity and β-carotene bleaching inhibition activity were increased, whereas, 2,2-azinobis (3-ethyl benzothiazoline-6-sulfonic acid) diammonium salt (ABTS·(+)), ferric reducing antioxidant power (FRAP), metal chelating and superoxide anion scavenging activity were similar to unprocessed ones. In contrary, except dry heating in C. gladiata, all other processing methods significantly (P<0.05) reduced the 2,2'-diphenyl-1-picryl-hydrazyl (DPPH·) (20-35%), ABTS·(+) (22-75%), FRAP (34-74%), metal chelating (30-41%), superoxide anion radical scavenging (8-80%), hydroxyl radical scavenging (20-40%) and β-carotene bleaching inhibition activity (15-69%). In addition, the sample extracts of raw and dry heated samples protected DNA damage at 10 μg. All processing methods in E. scandens and dry heating in C. gladiata would be a suitable method for adopting in domestic or industrial processing. Copyright © 2012 Elsevier Ltd. All rights reserved.

Inhibition of Procarcinogen Activating Enzyme CYP1A2 Activity and Free Radical Formation by Caffeic Acid and its Amide Analogues.

PubMed

Narongchai, Paitoon; Niwatananun, Kanokporn; Narongchai, Siripun; Kusirisin, Winthana; Jaikang, Churdsak

2016-01-01

Caffeic acid (CAF) and its amide analogues, ethyl 1-(3',4'-dihydroxyphenyl) propen amide (EDPA), phenethyl 1-(3',4'-dihydroxyphenyl) propen amide (PEDPA), phenmethyl 1- (3',4'-dihydroxyphenyl) propen amide (PMDPA) and octyl 1-(3',4'-dihydroxyphenyl) propen amide (ODPA) were investigated for the inhibition of procarcinogen activating enzyme. CYP1A2 and scavenging activity on formation of nitric oxide, superoxide anion, DPPH radical and hydroxyl radical. It was found that they inhibited CYP1A2 enzyme by uncompetitive inhibition. Apparent Ki values of CAF, EDPA, PEDPA, PMDPA and ODPA were 0.59, 0.39, 0.45, 0.75 and 0.80 µM, respectively suggesting potent inhibitors of CYP1A2. Moreover, they potentially scavenged nitric oxide radical with IC 50 values of 0.12, 0.22, 0.28, 0.22 and 0.51 mM, respectively. The IC50 values of superoxide anion scavenging were 0.20, 0.22, 0.44, 2.18 and 2.50 mM, respectively. 1, 1- diphenyl-2- picrylhydrazyl (DPPH) radical-scavenging ability, shown as IC50 values, were 0.41, 0.29, 0.30, 0.89 and 0.84 mM, respectively. Moreover, the hydroxyl radical scavenging in vitro model was shown as IC50 values of 23.22, 21.06, 17.10, 17.21 and 15.81 µM, respectively. From our results, caffeic acid and its amide analogues are in vitro inhibitors of human CYP1A2 catalytic activity and free radical formation. They may be useful to be developed as potential chemopreventive agents that block CYP1A2-mediated chemical carcinogenesis.

Role of endolymphatic anion transport in forskolin-induced Cl- activity increase of scala media.

PubMed

Kitano, I; Mori, N; Matsunaga, T

1995-03-01

To determine the role of anion transport in the forskolin-induced Cl- increase of scala media (SM), effects of forskolin on the EP (endocochlear potential) and Cl- activity (ACl) in SM were examined with double-barrelled Cl(-)-selective microelectrodes. The experiments were carried out on guinea pig cochleae, using a few anion transport inhibitors: IAA-94 for a Cl- channel blocker, bumetanide (BU) for an Na+/K+/2Cl- cotransport blocker, and SITS and DIDS for Cl-/HCO3- exchange blockers. The application of forskolin (200 microM) into scala vestibuli (SV) caused a 20 mEq increase of endolymphatic ACl and a 15 mV elevation of EP, and IAA-94 with forskolin completely abolished these responses. Although each application of BU, SITS or DIDS did not completely suppress EP elevation, the concurrent application of these inhibitors completely suppressed EP with endolymphatic ACl increase. The results indicate the involvement of Cl- channels, Na+/K+/2Cl- cotransport and Cl-/HCO3- exchange in forskolin-induced increase of ACl and EP. The role of adenylate cyclase activation and Cl- transport in endolymph homeostasis was discussed.

Anion channels in the sea urchin sperm plasma membrane.

PubMed

Morales, E; de la Torre, L; Moy, G W; Vacquier, V D; Darszon, A

1993-10-01

Ionic fluxes in sea urchin sperm plasma membrane regulate cell motility and the acrosome reaction (AR). Although cationic channels mediate some of the ionic movements, little is known about anion channels in these cells. The fusion of sperm plasma membranes into lipid bilayers allowed identification of a 150 pS anion channel. This anion channel was enriched from detergent-solubilized sperm plasma membranes using a wheat germ agglutinin Sepharose column. Vesicles formed from this preparation were fused into black lipid membranes (BLM), yielding single channel anion-selective activity with the properties of those found in the sperm membranes. The following anion selectivity sequence was found: NO3- > CNS- > Br- > Cl-. This anion channel has a high open probability at the holding potentials tested, it is partially blocked by 4,4'-diisothiocyano-2,2'-stilbendisulfonic acid (DIDS), and it often displays substates. The sperm AR was also inhibited by DIDS.

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

PubMed

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

2011-07-01

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

Superoxide poisons mononuclear iron enzymes by causing mismetallation

PubMed Central

Gu, Mianzhi; Imlay, James A.

2013-01-01

Summary Superoxide (O2−) is a primary agent of intracellular oxidative stress. Genetic studies in many organisms have confirmed that excess O2− disrupts metabolism, but to date only a small family of [4Fe-4S] dehydratases have been identified as direct targets. This investigation reveals that in Escherichia coli O2− also poisons a broader cohort of non-redox enzymes that employ ferrous iron atoms as catalytic cofactors. These enzymes were inactivated by O2− both in vitro and in vivo. Although the enzymes are known targets of hydrogen peroxide, the outcome with O2− differs substantially. When purified enzymes were damaged by O2− in vitro, activity could be completely restored by iron addition, indicating that the O2− treatment generated an apoprotein without damaging the protein polypeptide. Superoxide stress inside cells caused the progressive mismetallation of these enzymes with zinc, which confers little activity. When O2− stress was terminated, cells gradually restored activity by extracting zinc from the proteins. The overloading of cells with zinc caused mismetallation even without O2− stress. These results support a model in which O2− repeatedly excises iron from these enzymes, allowing zinc to compete with iron for remetallation of their apoprotein forms. This action substantially expands the physiological imprint of O2− stress. PMID:23678969

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

PubMed Central

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

2003-01-01

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

The activity of superoxide dismutases (SODs) at the early stages of wheat deetiolation

PubMed Central

Zimak-Piekarczyk, Paulina; Ślesak, Ireneusz

2018-01-01

Unbound tetrapyrroles, i.e. protochlorophyllide (Pchlide), chlorophyllide and chlorophylls, bring the risk of reactive oxygen species (ROS) being generated in the initial stages of angiosperm deetiolation due to inefficient usage of the excitation energy for photosynthetic photochemistry. We analyzed the activity of superoxide dismutases (SODs) in etiolated wheat (Triticum aestivum) leaves and at the beginning of their deetiolation. Mn-SOD and three isoforms of Cu/Zn-SODs were identified both in etiolated and greening leaves of T. aestivum. Two Cu/Zn-SODs, denoted as II and III, were found in plastids. The activity of plastidic Cu/Zn-SOD isoforms as well as that of Mn-SOD correlated with cell aging along a monocot leaf, being the highest at leaf tips. Moreover, a high Pchlide content at leaf tips was observed. No correlation between SOD activity and the accumulation of photoactive Pchlide, i.e. Pchlide bound into ternary Pchlide:Pchlide oxidoreductase:NADPH complexes was found. Cu/Zn-SOD I showed the highest activity at the leaf base. A flash of light induced photoreduction of the photoactive Pchlide to chlorophyllide as well as an increase in all the SODs activity which occurred in a minute time-scale. In the case of seedlings that were deetiolated under continuous light of moderate intensity (100 μmol photons m-2 s-1), only some fluctuations in plastidic Cu/Zn-SODs and Mn-SOD within the first four hours of greening were noticed. The activity of SODs is discussed with respect to the assembly of tetrapyrroles within pigment-protein complexes, monitored by fluorescence spectroscopy at 77 K. PMID:29558520

Removal of bromide and iodide anions from drinking water by silver-activated carbon aerogels.

PubMed

Sánchez-Polo, M; Rivera-Utrilla, J; Salhi, E; von Gunten, U

2006-08-01

The aim of this study is to analyze the use of Ag-doped activated carbon aerogels for bromide and iodide removal from drinking water and to study how the activation of Ag-doped aerogels affects their behavior. It has been observed that the carbonization treatment and activation process of Ag-doped aerogels increased the surface area value ( [Formula: see text] ), whereas the volume of meso-(V(2)) and macropores (V(3)) decreased slightly. Chemical characterization of the materials revealed that carbonization and especially activation process considerably increased the surface basicity of the sample. Original sample (A) presented acidic surface properties (pH(PZC)=4.5) with 21% surface oxygen, whereas the sample that underwent activation showed mainly basic surface chemical properties (pH(PZC)=9.5) with only 6% of surface oxygen. Carbonization and especially, activation process considerable increased the adsorption capacity of bromide and iodide ions. This would mainly be produced by (i) an increase in the microporosity of the sample, which increases Ag-adsorption sites available to halide anions, and (ii) a rise of the basicity of the sample, which produces an increase in attractive electrostatic interactions between the aerogel surface, positively charged at the working pH (pH(solution)activation processes increased the adsorptive capacity of the aerogel sample. However, results showed that the adsorption capacity of the aerogel samples studied was considerably lower in water from Lake Zurich. Results showed X(0.02) (amount adsorbed to initial breakthrough) values of 0.1 and 4.3 mg/g for chloride anion and dissolved organic carbon (DOC), respectively, during bromide adsorption process in water from Lake Zurich

The sites and topology of mitochondrial superoxide production

PubMed Central

Brand, Martin D.

2010-01-01

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

Molecular Insights of p47phox Phosphorylation Dynamics in the Regulation of NADPH Oxidase Activation and Superoxide Production*

PubMed Central

Meijles, Daniel N.; Fan, Lampson M.; Howlin, Brendan J.; Li, Jian-Mei

2014-01-01

Phagocyte superoxide production by a multicomponent NADPH oxidase is important in host defense against microbial invasion. However inappropriate NADPH oxidase activation causes inflammation. Endothelial cells express NADPH oxidase and endothelial oxidative stress due to prolonged NADPH oxidase activation predisposes many diseases. Discovering the mechanism of NADPH oxidase activation is essential for developing novel treatment of these diseases. The p47phox is a key regulatory subunit of NADPH oxidase; however, due to the lack of full protein structural information, the mechanistic insight of p47phox phosphorylation in NADPH oxidase activation remains incomplete. Based on crystal structures of three functional domains, we generated a computational structural model of the full p47phox protein. Using a combination of in silico phosphorylation, molecular dynamics simulation and protein/protein docking, we discovered that the C-terminal tail of p47phox is critical for stabilizing its autoinhibited structure. Ser-379 phosphorylation disrupts H-bonds that link the C-terminal tail to the autoinhibitory region (AIR) and the tandem Src homology 3 (SH3) domains, allowing the AIR to undergo phosphorylation to expose the SH3 pocket for p22phox binding. These findings were confirmed by site-directed mutagenesis and gene transfection of p47phox−/− coronary microvascular cells. Compared with wild-type p47phox cDNA transfected cells, the single mutation of S379A completely blocked p47phox membrane translocation, binding to p22phox and endothelial O2⨪ production in response to acute stimulation of PKC. p47phox C-terminal tail plays a key role in stabilizing intramolecular interactions at rest. Ser-379 phosphorylation is a molecular switch which initiates p47phox conformational changes and NADPH oxidase-dependent superoxide production by cells. PMID:24970888

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

PubMed

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

2008-02-15

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

Ultraslow Phase Transitions in an Anion-Anion Hydrogen-Bonded Ionic Liquid.

PubMed

Faria, Luiz F O; Lima, Thamires A; Ferreira, Fabio F; Ribeiro, Mauro C C

2018-02-15

A Raman spectroscopy study of 1-ethyl-3-methylimidazolium hydrogen sulfate, [C 2 C 1 im][HSO 4 ], as a function of temperature, has been performed to reveal the role played by anion-anion hydrogen bond on the phase transitions of this ionic liquid. Anion-anion hydrogen bonding implies high viscosity, good glass-forming ability, and also moderate fragility of [C 2 C 1 im][HSO 4 ] in comparison with other ionic liquids. Heating [C 2 C 1 im][HSO 4 ] from the glassy phase results in cold crystallization at ∼245 K. A solid-solid transition (crystal I → crystal II) is barely discernible in calorimetric measurements at typical heating rates, but it is clearly revealed by Raman spectroscopy and X-ray diffraction. Raman spectroscopy indicates that crystal I has extended ([HSO 4 ] - ) n chains of hydrogen-bonded anions but crystal II has not. Raman spectra recorded at isothermal condition show the ultraslow dynamics of cold crystallization, solid-solid transition, and continuous melting of [C 2 C 1 im][HSO 4 ]. A brief comparison is also provided between [C 2 C 1 im][HSO 4 ] and [C 4 C 1 im][HSO 4 ], as Raman spectroscopy shows that the latter does not form the crystalline phase with extended anion-anion chains.

Synthesis, crystal structure, superoxide scavenging activity, anticancer and docking studies of novel adamantyl nitroxide derivatives

NASA Astrophysics Data System (ADS)

Zhu, Xiao-he; Sun, Jin; Wang, Shan; Bu, Wei; Yao, Min-na; Gao, Kai; Song, Ying; Zhao, Jin-yi; Lu, Cheng-tao; Zhang, En-hu; Yang, Zhi-fu; Wen, Ai-dong

2016-03-01

A novel adamantyl nitroxide derivatives has been synthesized and characterized by IR, ESI-MS and elemental analysis. Quantum chemical calculations have also been performed to calculate the molecular geometry using density functional theory (B3LYP) with the 6-31G (d,p) basis set. The calculated results showed that the optimized geometry can well reproduce the crystal structure. The antioxidant and antiproliferative activity were evaluated by superoxide (NBT) and MTT assay. The adamantyl nitroxide derivatives exhibited stronger scavenging ability towards O2· - radicals when compared to Vitamin C, and demonstrated a remarked anticancer activity against all the tested cell lines, especially Bel-7404 cells with IC50 of 43.3 μM, compared to the positive control Sorafenib (IC50 = 92.0 μM). The results of molecular docking within EGFR using AutoDock confirmed that the titled compound favorably fitted into the ATP binding site of EGFR and would be a potential anticancer agent.

Quantification of superoxide radical production in thylakoid membrane using cyclic hydroxylamines.

PubMed

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

2015-12-01

Applicability of two lipophilic cyclic hydroxylamines (CHAs), CM-H and TMT-H, and two hydrophilic CHAs, CAT1-H and DCP-H, for detection of superoxide anion radical (O2(∙-)) produced by the thylakoid photosynthetic electron transfer chain (PETC) of higher plants under illumination has been studied. ESR spectrometry was applied for detection of the nitroxide radical originating due to CHAs oxidation by O2(∙-). CHAs and corresponding nitroxide radicals were shown to be involved in side reactions with PETC which could cause miscalculation of O2(∙-) production rate. Lipophilic CM-H was oxidized by PETC components, reducing the oxidized donor of Photosystem I, P700(+), while at the same concentration another lipophilic CHA, TMT-H, did not reduce P700(+). The nitroxide radical was able to accept electrons from components of the photosynthetic chain. Electrostatic interaction of stable cation CAT1-H with the membrane surface was suggested. Water-soluble superoxide dismutase (SOD) was added in order to suppress the reaction of CHA with O2(∙-) outside the membrane. SOD almost completely inhibited light-induced accumulation of DCP(∙), nitroxide radical derivative of hydrophilic DCP-H, in contrast to TMT(∙) accumulation. Based on the results showing that change in the thylakoid lumen pH and volume had minor effect on TMT(∙) accumulation, the reaction of TMT-H with O2(∙-) in the lumen was excluded. Addition of TMT-H to thylakoid suspension in the presence of SOD resulted in the increase in light-induced O2 uptake rate, that argued in favor of TMT-H ability to detect O2(∙-) produced within the membrane core. Thus, hydrophilic DCP-H and lipophilic TMT-H were shown to be usable for detection of O2(∙-) produced outside and within thylakoid membranes. Copyright © 2015 Elsevier Inc. All rights reserved.

A facile way to fabricate manganese phosphate self-assembled carbon networks as efficient electrochemical catalysts for real-time monitoring of superoxide anions released from HepG2 cells.

PubMed

Cai, Xuan; Shi, Libo; Sun, Wenqian; Zhao, Hongli; Li, Hong; He, Haiyan; Lan, Minbo

2018-04-15

Quantification of superoxide anions (O 2 •- ) is significant in the monitoring of many serious diseases and the design of enzyme-mimic catalysts plays the main role in the development of non-enzymatic O 2 •- sensors. Herein, we proposed a facile self-assembly process to synthesize manganese phosphate modified carbon networks using three kinds of widely-used carbon materials (MWCNTs, NGS and GO) as pillar connectors. Characterizations demonstrate that manganese phosphate is widely dispersed inside and on the surface of carbon networks without visible morphology. Meanwhile, all three kinds of synthesized catalysts were successfully immobilized on the screen-printed carbon electrodes to evaluate the electrochemical performance of fabricated sensors. The results indicate that sensors based on Mn x (PO 4 ) y modified MWCNTs exhibit high sensitivity with an extremely low detection limit of 0.127μM (S/N = 3) and a wide liner range of 0-1.817mM (R 2 = 0.998). We further employed the recommended sensors in the real-time monitoring of HepG2 cells released O 2 •- under the stimulating of Zymosan (20mg/mL). Noticeably, the proposed sensors exhibit not only sensitive response but also stable current steps upon different addition of Zymosan. The calculated concentrations of cell-released O 2 •- vary from 6.772 to 24.652pM cell -1 for the Zymosan amount used in this work. The established novel sensors display low background current and signal noises, thus holding unique advantages in the trace analysis of O 2 •- in biological samples and in vivo environment. Copyright © 2017 Elsevier B.V. All rights reserved.

Artificial neural network optimization of Althaea rosea seeds polysaccharides and its antioxidant activity.

PubMed

Liu, Feng; Liu, Wenhui; Tian, Shuge

2014-09-01

A combination of an orthogonal L16(4)4 test design and a three-layer artificial neural network (ANN) model was applied to optimize polysaccharides from Althaea rosea seeds extracted by hot water method. The highest optimal experimental yield of A. rosea seed polysaccharides (ARSPs) of 59.85 mg/g was obtained using three extraction numbers, 113 min extraction time, 60.0% ethanol concentration, and 1:41 solid-liquid ratio. Under these optimized conditions, the ARSP experimental yield was very close to the predicted yield of 60.07 mg/g and was higher than the orthogonal test results (40.86 mg/g). Structural characterizations were conducted using physicochemical property and FTIR analysis. In addition, the study of ARSP antioxidant activity demonstrated that polysaccharides exhibited high superoxide dismutase activity, strong reducing power, and positive scavenging activity on superoxide anion, hydroxyl radical, 2,2-diphenyl-1-picrylhydrazyl, and reducing power. Our results indicated that ANNs were efficient quantitative tools for predicting the total ARSP content. Copyright © 2014 Elsevier B.V. All rights reserved.

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

PubMed

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

2015-12-01

Understanding the cellular stress response in honey bees will significantly contribute to their conservation. The aim of this study was to analyze the response of the antioxidative enzymes superoxide dismutase and catalase in honey bees related to the presence of toxic metals in different habitats. Three locations were selected: (i) Tunovo on the mountain Golija, as control area, without industry and large human impact, (ii) Belgrade as urban area, and (iii) Zajača, as mining and industrial zone. Our results showed that the concentrations of lead (Pb) in whole body of bees vary according to habitat, but there was very significant increase of Pb in bees from investigated industrial area. Bees from urban and industrial area had increased expression of both Sod1 and Cat genes, suggesting adaptation to increased oxidative stress. However, in spite increased gene expression, the enzyme activity of catalase was lower in bees from industrial area suggesting inhibitory effect of Pb on catalase. © 2015 Wiley Periodicals, Inc.

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

PubMed

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

2008-04-18

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

Simultaneous anionic and cationic redox

NASA Astrophysics Data System (ADS)

Jung, Sung-Kyun; Kang, Kisuk

2017-12-01

It is challenging to unlock anionic redox activity, accompanied by full utilization of available cationic redox process, to boost capacity of battery cathodes. Now, material design by tuning the metal-oxygen interaction is shown to be a promising solution.

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

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

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

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

Anions in Cometary Comae

NASA Technical Reports Server (NTRS)

Charnley, Steven B.

2011-01-01

The presence of negative ions (anions) in cometary comae is known from Giotto mass spectrometry of IP/Halley. The anions 0-, OH-, C-, CH- and CN- have been detected, as well as unidentified anions with masses 22-65 and 85-110 amu (Chaizy et al. 1991). Organic molecular anions are known to have a significant impact on the charge balance of interstellar clouds and circumstellar envelopes and have been shown to act as catalysts for the gas-phase synthesis of larger hydrocarbon molecules in the ISM, but their importance in cometary comae has not yet been explored. We present details of the first attempt to model the chemistry of anions in cometary comae. Based on the combined chemical and hydro dynamical model of Rodgers & Charnley (2002), we investigate the role of large carbon-chain anions in cometary coma chemistry. We calculate the effects of these anions on coma thermodynamics, charge balance and examine their impact on molecule formation.

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

PubMed

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

2017-10-01

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

Extraction, characterisation and antioxidant activity of Allium sativum polysaccharide.

PubMed

Cheng, Hao; Huang, Gangliang

2018-07-15

Extraction and antioxidant activity of polysaccharide from Allium sativum were investigated. The crude polysaccharide was obtained by the hot-water extraction method. The molecular weight of polysaccharide deproteinized with CaCl 2 was 7.35×10 3 . It indicated that polysaccharide from Allium sativum consisted of three monosaccharides, namely fructose, glucose, and galactose by HPLC. The polysaccharide had the β-glycosidic bond. Moreover, it was proved that the polysaccharide had the potential scavenging ability to superoxide anions and hydroxyl radicals. So, it should be a potential antioxidant. Copyright © 2018 Elsevier B.V. All rights reserved.

Activator anion binding site in pyridoxal phosphorylase b: the binding of phosphite, phosphate, and fluorophosphate in the crystal.

PubMed Central

Oikonomakos, N. G.; Zographos, S. E.; Tsitsanou, K. E.; Johnson, L. N.; Acharya, K. R.

1996-01-01

It has been established that phosphate analogues can activate glycogen phosphorylase reconstituted with pyridoxal in place of the natural cofactor pyridoxal 5'-phosphate (Change YC. McCalmont T, Graves DJ. 1983. Biochemistry 22:4987-4993). Pyridoxal phosphorylase b has been studied by kinetic, ultracentrifugation, and X-ray crystallographic experiments. In solution, the catalytically active species of pyridoxal phosphorylase b adopts a conformation that is more R-state-like than that of native phosphorylase b, but an inactive dimeric species of the enzyme can be stabilized by activator phosphite in combination with the T-state inhibitor glucose. Co-crystals of pyridoxal phosphorylase b complexed with either phosphite, phosphate, or fluorophosphate, the inhibitor glucose, and the weak activator IMP were grown in space group P4(3)2(1)2, with native-like unit cell dimensions, and the structures of the complexes have been refined to give crystallographic R factors of 18.5-19.2%, for data between 8 and 2.4 A resolution. The anions bind tightly at the catalytic site in a similar but not identical position to that occupied by the cofactor 5'-phosphate group in the native enzyme (phosphorus to phosphorus atoms distance = 1.2 A). The structural results show that the structures of the pyridoxal phosphorylase b-anion-glucose-IMP complexes are overall similar to the glucose complex of native T-state phosphorylase b. Structural comparisons suggest that the bound anions, in the position observed in the crystal, might have a structural role for effective catalysis. PMID:8976550

A protein with anion exchange properties found in the kidney proximal tubule.

PubMed

Soleimani, M; Bizal, G L; Anderson, C C

1993-09-01

One important mechanism for reabsorption of chloride in the kidney proximal tubule involves anion exchange of chloride for a base. Anion exchange transport systems in general demonstrate sensitivity to inhibition by disulfonic stilbenes, probenecid, furosemide, and the arginyl amino group modifier phenylglyoxal. Using disulfonic stilbene affinity chromatography, we have identified and partially purified a protein with anion exchanger properties in luminal membrane vesicles isolated from rabbit kidney cortex. This protein has a molecular weight of 162 kD. The binding of the 162 kD protein to the stilbene affinity matrix is inhibited by disulfonic stilbenes, probenecid, furosemide, and phenylglyoxal. Reconstitution of the proteins eluted from the affinity matrix into liposomes demonstrates anion exchange activity as assayed by radiolabeled chloride influx. Deletion of the 162 kD protein from the eluted mixture by probenecid diminishes the anion exchanger activity in the reconstituted liposomes. Further purification of the disulfonic stilbene column eluant by Econo-Pac Q ion exchange chromatography resulted in significant enrichment in 162 kD protein abundance and also anion exchange activity in reconstituted liposomes. The results of the above experiments strongly suggest that the 162 kD protein is an anion exchanger. Insight into the functional and molecular characteristics of this protein should provide important information about the mechanism(s) of chloride reabsorption in the kidney proximal tubule.

Isatinphenylsemicarbazones as efficient colorimetric sensors for fluoride and acetate anions - anions induce tautomerism.

PubMed

Jakusová, Klaudia; Donovalová, Jana; Cigáň, Marek; Gáplovský, Martin; Garaj, Vladimír; Gáplovský, Anton

2014-04-05

The anion induced tautomerism of isatin-3-4-phenyl(semicarbazone) derivatives is studied herein. The interaction of F(-), AcO(-), H2PO4(-), Br(-) or HSO4(-) anions with E and Z isomers of isatin-3-4-phenyl(semicarbazone) and N-methylisatin-3-4-phenyl(semicarbazone) as sensors influences the tautomeric equilibrium of these sensors in the liquid phase. This tautomeric equilibrium is affected by (1) the inter- and intra-molecular interactions' modulation of isatinphenylsemicarbazone molecules due to the anion induced change in the solvation shell of receptor molecules and (2) the sensor-anion interaction with the urea hydrogens. The acid-base properties of anions and the difference in sensor structure influence the equilibrium ratio of the individual tautomeric forms. Here, the tautomeric equilibrium changes were indicated by "naked-eye" experiment, UV-VIS spectral and (1)H NMR titration, resulting in confirmation that appropriate selection of experimental conditions leads to a high degree of sensor selectivity for some investigated anions. Sensors' E and Z isomers differ in sensitivity, selectivity and sensing mechanism. Detection of F(-) or CH3COO(-) anions at high weakly basic anions' excess is possible. Copyright © 2014 Elsevier B.V. All rights reserved.

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

PubMed

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

2003-01-01

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

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

PubMed

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

1998-05-22

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

Process for the preparation of calcium superoxide

NASA Technical Reports Server (NTRS)

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

1978-01-01

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

INF-γ Enhances Nox2 Activity by Upregulating phox Proteins When Applied to Differentiating PLB-985 Cells but Does Not Induce Nox2 Activity by Itself.

PubMed

Ellison, Michael A; Thurman, Gail; Gearheart, Christy M; Seewald, Ryan H; Porter, Christopher C; Ambruso, Daniel R

2015-01-01

The cytokine and drug interferon-γ enhances superoxide anion production by the antimicrobicidal Nox2 enzyme of neutrophils. Because mature neutrophils have a short lifespan, we hypothesized that the effects of interferon-γ on these cells might be mediated by its prolonged exposure to differentiating neutrophil precursors in the bone marrow rather than its brief exposure to mature circulating neutrophils. Effects of INF-Γ on NOX2 activity: To address this possibility we exposed the myeloid PLB-985 cell line to interferon-γ for 3 days in the presence of dimethyl sulfoxide which induces terminal differentiation of these cells. Interferon-γ was found to enhance superoxide production by Nox2 in a concentration dependent manner. In contrast, application of interferon-γ alone for 3 days failed to induce detectible Nox2 activity. Additionally, application of interferon-γ for 3 hours to pre-differentiated PLB-985 cells, which models studies using isolated neutrophils, was much less effective at enhancing superoxide anion production. Effects of INF-Γ on phox protein levels: Addition of interferon-γ during differentiation was found to upregulate the Nox2 proteins gp91phox and p47phox in concert with elevated transcription of their genes. The p22phox protein was upregulated in the absence of increased transcription presumably reflecting stabilization resulting from binding to the elevated gp91phox. Thus, increased levels of gp91phox, p47phox and p22phox likely account for the interferon-γ mediated enhancement of dimethyl sulfoxide-induced Nox2 activity. In contrast, although interferon-γ alone also increased various phox proteins and their mRNAs, the pattern was very different to that seen with interferon-γ plus dimethyl sulfoxide. In particular, p47phox was not induced thus explaining the inability of interferon -γ alone to enhance Nox2 activity. Short application of interferon-γ to already differentiated cells failed to increase any phox proteins. Our findings

Influence of Rhodococcus equi on the respiratory burst of resident alveolar macrophages from horses

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

Brumbaugh, G.W.

1986-01-01

Rhodococcus equi is the etiologic agent of a devastating pneumonia of sporadic incidence in foals. The purpose of this study was to evaluate the influence of R. equi on the superoxide anion production, measured spectrophotometrically as the reduction of cytochrome C, and hexose monophosphate shunt activity, measured by /sup 14/CO/sub 2/ liberation from /sup 14/C-1-D-glucose, of alveolar macrophages from horses. Alveolar macrophages were harvested from 6 anesthetized, healthy, light-breed, adult horses by bronchoalveolar lavage. Following a randomized complete block design, the suspension of cells was divided into aliquots of 10/sup 6/ viable alveolar macrophages which were exposed to 1, 10more » or 100 g. of opsonized R. equi or opsonized zymosan A at 37 C for 2 hours. In this study the respiratory burst of equine alveolar macrophages was only evidenced by the hexose monophosphate shunt activity and superoxide anion was not coincidentally produced. Rhodococcus equi did not adversely affect that response. The insignificant superoxide anion production by the alveolar macrophages suggests that this may not be a significant oxygen metabolite in those cells.« less

Free radical scavengers and antioxidants from Lemongrass (Cymbopogon citratus (DC.) Stapf.).

PubMed

Cheel, José; Theoduloz, Cristina; Rodríguez, Jaime; Schmeda-Hirschmann, Guillermo

2005-04-06

Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 microg/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 microg/mL and were inactive toward the XO at 50 microg/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2' '-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC(50): 9-10 microM) and inhibited lipid peroxidation by 70% at 100 microg/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC(50) values of 68.8 and 54.2 microM, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 microg/mL.

Role of ERK1/2 kinase in the expression of iNOS by NDMA in human neutrophils.

PubMed

Ratajczak-Wrona, Wioletta; Jablonska, Ewa; Garley, Marzena; Jablonski, Jakub; Radziwon, Piotr

2013-01-01

Potential role of ERK1/2 kinase in conjunction with p38 in the regulation of inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production, and superoxide anion generation by human neutrophils (PMNs) exposed to N-nitrosodimethylamine (NDMA) was determined. Increased synthesis of NO due to the involvement of iNOS in neutrophils exposed to NDMA was observed. In addition, intensified activation of ERK1/2 and p38 kinases was determined in these cells. Inhibition of kinase regulated by extracellular signals (ERK1/2) pathway, in contrast to p38 pathway, led to an increased production of NO and expression of iNOS in PMNs. Moreover, as a result of inhibition of ERK1/2 pathway, a decreased activation of p38 kinase was observed in neutrophils, while inhibition of p38 kinase did not affect activation of ERK1/2 pathway in these cells. An increased ability to release superoxide anion by the studied PMNs was observed, which decreased after ERK1/2 pathway inhibition. In conclusion, in human neutrophils, ERK1/2 kinase is not directly involved in the regulation of iNOS and NO production induced by NDMA; however, the kinase participates in superoxide anion production in these cells.

Effects of short-term anoxia treatment on browning of fresh-cut Chinese water chestnut in relation to antioxidant activity.

PubMed

You, Yanli; Jiang, Yueming; Sun, Jian; Liu, Hai; Song, Lili; Duan, Xuewu

2012-06-01

The effects of short-term anoxia pre-treatment on browning of fresh-cut Chinese water chestnut (CWC), stored at 4°C, in relation to antioxidant activity were investigated. CWC slices were exposed to pure N 2 for 4h and then stored at 4°C for 18d. Anoxia significantly inhibited browning of CWC slices during storage, accompanied by lower contents of malondialdehyde, H 2 O 2 , and lipoxygenase activity. Furthermore, anoxia induced the activities of superoxide dismutase and ascorbate peroxidase, which could benefit scavenging reactive oxygen species and alleviating lipid peroxidation. In addition, better maintenance of reducing power and free-radical-scavenging activities against α,α-diphenyl-β-picrylhydrazy (DPPH), superoxide anions and hydroxyl was observed in N 2 -treated CWC slices, with higher phenolic compounds and ascorbic acid contents. Collectively, these finds suggest that N 2 pre-treatment enhanced enzymatic and non-enzymatic antioxidant activity in CWC slices, and thereby contributed to alleviating lipid peroxidation and maintenance of storage quality. Copyright © 2011 Elsevier Ltd. All rights reserved.

Inactivation of catecholamines by superoxide gives new insights on the pathogenesis of septic shock

PubMed Central

Macarthur, Heather; Westfall, Thomas C.; Riley, Dennis P.; Misko, Thomas P.; Salvemini, Daniela

2000-01-01

A major feature of septic shock is the development of a vascular crisis characterized by nonresponsiveness to sympathetic vasoconstrictor agents and the subsequent irreversible fall in blood pressure. In addition, sepsis, like other inflammatory conditions, results in a large increase in the production of free radicals, including superoxide anions (O2⨪) within the body. Here we show that O2⨪ reacts with catecholamines deactivating them in vitro. Moreover, this deactivation would appear to account for the hyporeactivity to exogenous catecholamines observed in sepsis, because administration of a superoxide dismutase (SOD) mimetic to a rat model of septic shock to remove excess O2⨪ restored the vasopressor responses to norepinephrine. This treatment with the SOD mimetic also reversed the hypotension in these animals; suggesting that deactivation of endogenous norepinephrine by O2⨪ contributes significantly to this aspect of the vascular crisis. Indeed, the plasma concentrations of both norepinephrine and epinephrine in septic rats treated with the SOD mimetic were significantly higher than in untreated rats. Interestingly, the plasma concentrations for norepinephrine and epinephrine were inversely related to the plasma concentrations of adrenochromes, the product of the autoxidation of catecholamines initiated by O2⨪. We propose, therefore, that the use of a SOD mimetic represents a new paradigm for the treatment of septic shock. By removing O2⨪, exogenous and endogenous catecholamines are protected from autoxidation. As a result, both hyporeactivity and hypotension are reversed, generation of potentially toxic adrenochromes is reduced, and survival rate is improved. PMID:10944234

Mitochondrial superoxide dismutase activation with 17 β-estradiol-treated human lens epithelial cells

PubMed Central

Gottipati, Srinivas

2008-01-01

Purpose 17 β-estradiol (17β-E2) protects human lens epithelial cells against oxidative stress by preserving mitochondrial function in part via the non-genomic rapid activation of prosurvival signal transduction pathways. The study described herein examined whether 17β-E2 also elicits genomic protection by influencing the expression (and activity) of mitochondrial-associated manganese superoxide dismutase (MnSOD) as a possible parallel mechanism by which 17β-E2 protects against oxidative stress. Methods Virally-transformed human lens epithelial cells (HLE-B3) were pre-incubated with 17β-E2, and mRNA or protein lysates were collected over a time course ranging from 90 min to 24 h. Positive expression of lens epithelial cell MnSOD mRNA was determined by semi-quantitative reverse transcriptase polymerase chain reaction (RT–PCR), and its levels were monitored by real-time PCR up to 24 h after 17β-E2 administration. Western blot analysis was used to examine the pattern of protein expression as influenced by 17β-E2 treatment. MnSOD activity as influenced by 17β-E2 was determined by measuring enzymatic activity. Results A significant rapid increase in the activity of MnSOD was observed with HLE-B3 cells by 90 min post-bolus addition of 17β-E2, which returned to control level by 240 min. Neither an increase in MnSOD mRNA nor in protein expression was detected up through 24 h. Conclusions These data demonstrate that 17β-E2 rapidly and transiently increases the activity of MnSOD but influences neither its mRNA expression nor its protein expression. The results suggest that (estrogen-activated) MnSOD plays an important role against mitochondrial oxidative stress by diminishing reactive oxygen species, thus promoting cell survival. PMID:18490963

Structure-Induced Reversible Anionic Redox Activity in Na Layered Oxide Cathode

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

Rong, Xiaohui; Liu, Jue; Hu, Enyuan

Anionic redox reaction (ARR) in lithium- and sodium-ion batteries is under hot discussion, mainly regarding how oxygen anion participates and to what extent oxygen can be reversibly oxidized and reduced. In this paper, a P3-type Na 0.6[Li 0.2Mn 0.8]O 2 with reversible capacity from pure ARR was studied. The interlayer O-O distance (peroxo-like O-O dimer, 2.506(3) Å), associated with oxidization of oxygen anions, was directly detected by using a neutron total scattering technique. Finally, different from Li 2RuO 3 or Li 2IrO 3 with strong metal-oxygen (M-O) bonding, for P3-type Na 0.6[Li 0.2Mn 0.8]O 2 with relatively weak Mn-O covalentmore » bonding, crystal structure factors might play an even more important role in stabilizing the oxidized species, as both Li and Mn ions are immobile in the structure and thus may inhibit the irreversible transformation of the oxidized species to O 2 gas.« less

Structure-Induced Reversible Anionic Redox Activity in Na Layered Oxide Cathode

DOE PAGES

Rong, Xiaohui; Liu, Jue; Hu, Enyuan; ...

2017-11-01

Anionic redox reaction (ARR) in lithium- and sodium-ion batteries is under hot discussion, mainly regarding how oxygen anion participates and to what extent oxygen can be reversibly oxidized and reduced. In this paper, a P3-type Na 0.6[Li 0.2Mn 0.8]O 2 with reversible capacity from pure ARR was studied. The interlayer O-O distance (peroxo-like O-O dimer, 2.506(3) Å), associated with oxidization of oxygen anions, was directly detected by using a neutron total scattering technique. Finally, different from Li 2RuO 3 or Li 2IrO 3 with strong metal-oxygen (M-O) bonding, for P3-type Na 0.6[Li 0.2Mn 0.8]O 2 with relatively weak Mn-O covalentmore » bonding, crystal structure factors might play an even more important role in stabilizing the oxidized species, as both Li and Mn ions are immobile in the structure and thus may inhibit the irreversible transformation of the oxidized species to O 2 gas.« less

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

PubMed Central

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

2011-01-01

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

Preliminary neutron diffraction analysis of challenging human manganese superoxide dismutase crystals

DOE PAGES

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

2017-03-29

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

Preliminary neutron diffraction analysis of challenging human manganese superoxide dismutase crystals

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

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

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

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

PubMed

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

2005-02-01

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

Novel estrogens and their radical scavenging effects, iron-chelating, and total antioxidative activities: 17 alpha-substituted analogs of delta 9(11)-dehydro-17 beta-estradiol.

PubMed

Römer, W; Oettel, M; Menzenbach, B; Droescher, P; Schwarz, S

1997-11-01

Antioxidant effects of N,N-dimethyl-p-toluidine, p-cresol, and p-(hydroxy)thioanisol 17 alpha-substituted analogs of 17 beta-estradiol and their delta 9(11)-dehydro homologs were investigated using four different in vitro models: rat synaptosomal lipid peroxidation induced by Fenton's reagent, Fe(II)-chelating activities, the formation of superoxide anion radicals, and total antioxidative activity. Whereas the classical estrogen 17 beta-estradiol as well as selected phenolic compounds was only moderately inhibiting iron-dependent lipid peroxidation and stimulating total antioxidative activity, besides delta 9(11)-dehydro-17 beta-estradiol (J 1213), novel estrogens such as C-17-oriented side chain analogs of 17 beta-estradiol (J 843, J 872, and J 897) and delta 9(11)-dehydro homologs (J 844, J 864, and J 898) directly altered the iron redox chemistry and diminished the formation of superoxide anion radicals generated by a xanthine/xanthine oxidase-dependent luminescence reaction to a great extent. These results suggest that definite modifications in the chemical structure of 17 beta-estradiol, e.g., the introduction of a delta 9(11)-double bond and/or p-cresol as well as p-(hydroxy)thioanisol C-17 substitution, may result in substantial changes in their antioxidant behavior. These compounds may be drug candidates for treating pathologies related to free radical formation.

Redox and fungicidal properties of phthalocyanine metal complexes as related to active oxygen.

PubMed

Vol'pin, M E; Novodarova, G N; Krainova NYu; Lapikova, V P; Aver'yanov, A A

2000-10-01

Some chemical and fungicidal effects of 20 phthalocyanines of Co, Fe, Cu, and Al were studied. Under dark conditions, these complexes reduced nitroblue tetrazolium in the presence of KCN, accelerated the autoxidation of ascorbate or hydroquinone and decomposed hydrogen peroxide. In the later reaction, hydroxyl radical was generated as evidenced with the deoxyribose assay. The inhibition by superoxide dismutase and catalase of catalyzed autoxidation of ascorbate suggests the participation of superoxide anion-radical and hydrogen peroxide in the reaction. Most complexes were toxic to the fungus Magnaporthe grisea which causes blast disease of rice. The toxicity was enhanced by light being diminished by antioxidant reagents sequestering active oxygen species. Some complexes (including nontoxic ones), after 1-day contact with a leaf surface of the disease-susceptible rice cultivar, induced the fungitoxicity of leaf diffusate. This toxicity was also light-activated and sensitive to antioxidant reagents. Several complexes, when added to inocula, decreased 2-3 times the frequency of the compatible symptoms of the blast. It is suggested that in planta, the dark redox activity of phthalocyanines along with their photosensitization promote the generation of active oxygen, which damages the parasite and, therefore, favors disease resistance.

Chemical composition and antioxidant activities of the essential oil from Nandina domestica fruits.

PubMed

Bi, Shu-Feng; Zhu, Guang-Qi; Wu, Jie; Li, Zhong-Kang; Lv, Yong-Zhan; Fang, Ling

2016-01-01

The chemical composition and antioxidant activities of the essential oil from Nandina domestica fruits were studied for the first time. Twenty-two compounds, representing 82.79% of the oil, were identified from the oil. The major compounds were 3-hexen-1-ol (12.9%), linalool (12.3%), 2-methoxy-4-vinylphenol (9.9%), oleic acid (8.0%), furfural (5.8%) and 2,6-di-tert-butyl-4-methylphenol (5.7%). The antioxidant activities of the oil were evaluated using reducing power, metal chelating ability and scavenging capacity against 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethylbenzthiazoline-6-sulfonate (ABTS) and superoxide anion free radical. The oil exhibited significant antioxidant activities.

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

PubMed Central

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

2008-01-01

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

Superoxide Dismutase Mimics: Chemistry, Pharmacology, and Therapeutic Potential

PubMed Central

Rebouças, Júlio S.; Spasojević, Ivan

2010-01-01

Abstract Oxidative stress has become widely viewed as an underlying condition in a number of diseases, such as ischemia–reperfusion disorders, central nervous system disorders, cardiovascular conditions, cancer, and diabetes. Thus, natural and synthetic antioxidants have been actively sought. Superoxide dismutase is a first line of defense against oxidative stress under physiological and pathological conditions. Therefore, the development of therapeutics aimed at mimicking superoxide dismutase was a natural maneuver. Metalloporphyrins, as well as Mn cyclic polyamines, Mn salen derivatives and nitroxides were all originally developed as SOD mimics. The same thermodynamic and electrostatic properties that make them potent SOD mimics may allow them to reduce other reactive species such as peroxynitrite, peroxynitrite-derived CO3·−, peroxyl radical, and less efficiently H2O2. By doing so SOD mimics can decrease both primary and secondary oxidative events, the latter arising from the inhibition of cellular transcriptional activity. To better judge the therapeutic potential and the advantage of one over the other type of compound, comparative studies of different classes of drugs in the same cellular and/or animal models are needed. We here provide a comprehensive overview of the chemical properties and some in vivo effects observed with various classes of compounds with a special emphasis on porphyrin-based compounds. Antioxid. Redox Signal. 13, 877–918. PMID:20095865

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

PubMed Central

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

2014-01-01

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

Extracellular localization of catalase is associated with the transformed state of malignant cells.

PubMed

Böhm, Britta; Heinzelmann, Sonja; Motz, Manfred; Bauer, Georg

2015-12-01

Oncogenic transformation is dependent on activated membrane-associated NADPH oxidase (NOX). However, the resultant extracellular superoxide anions are also driving the NO/peroxynitrite and the HOCl pathway, which eliminates NOX-expressing transformed cells through selective apoptosis induction. Tumor progression is dependent on dominant interference with intercellular apoptosis-inducing ROS signaling through membrane-associated catalase, which decomposes H2O2 and peroxynitrite and oxidizes NO. Particularly, the decomposition of extracellular peroxynitrite strictly requires membrane-associated catalase. We utilized small interfering RNA (siRNA)-mediated knockdown of catalase and neutralizing antibodies directed against the enzyme in combination with challenging H2O2 or peroxynitrite to determine activity and localization of catalase in cells from three distinct steps of multistage oncogenesis. Nontransformed cells did not generate extracellular superoxide anions and only showed intracellular catalase activity. Transformed cells showed superoxide anion-dependent intercellular apoptosis-inducing ROS signaling in the presence of suboptimal catalase activity in their membrane. Tumor cells exhibited tight control of intercellular apoptosis-inducing ROS signaling through a high local concentration of membrane-associated catalase. These data demonstrate that translocation of catalase to the outside of the cell membrane is already associated with the transformation step. A strong local increase in the concentration of membrane-associated catalase is achieved during tumor progression and is controlled by tumor cell-derived H2O2 and by transglutaminase.

An in vitro examination of the antioxidant and anti-inflammatory properties of buckwheat honey.

PubMed

van den Berg, A J J; van den Worm, E; van Ufford, H C Quarles; Halkes, S B A; Hoekstra, M J; Beukelman, C J

2008-04-01

Hydroxyl radical and hypochlorite anion formed at the wound site from superoxide anion produced by activated polymorphonuclear neutrophils (PMNs) are considered important factors in impaired wound healing. Superoxide anion may also react with nitric oxide produced by macrophages to form peroxynitrite, a third strong oxidant that damages surrounding tissue. In order to select honey for use in wound-healing products, different samples were compared for their capacity to reduce levels of reactive oxygen species (ROS) in vitro. Honey samples were tested in assays for inhibition of ROS production by activated human PMNs, antioxidant activity (scavenging of superoxide anion in a cell-free system) and inhibition of human complement (reducing levels of ROS by limiting formation of complement factors that attract and stimulate PMNs). For buckwheat honey (NewYork, US), moisture and free acid content were determined by refractive index measurement and potentiometric titration respectively. Honey constituents other than sugars were investigated by thin layer chromatography, using natural product reagent to detect phenolic compounds. Constituents with antioxidant properties were detected by spraying the chromatogram with DPPH. Although most honey samples were shown to be active, significant differences were observed, with the highly active honey exceeding the activities of samples with minor effects by factors of 4 to 30. Most pronounced activities were found for American buckwheat honey from the state of NewYork. Phenolic constituents of buckwheat honey were shown to have antioxidant activity. As buckwheat honey was most effective in reducing ROS levels, it was selected for use in wound-healing products. The major antioxidant properties in buckwheat honey derive from its phenolic constituents, which are present in relatively large amounts. Its phenolic compounds may also exert antibacterial activity, whereas its low pH and high free acid content may assist wound healing.

The neuroprotective properties of the superoxide dismutase mimetic tempol correlate with its ability to reduce pathological glutamate release in a rodent model of stroke

PubMed Central

Dohare, Preeti; Hyzinski-García, María C.; Vipani, Aarshi; Bowens, Nicole H.; Nalwalk, Julia W.; Feustel, Paul J.; Keller, Richard W.; Jourd’heuil, David; Mongin, Alexander A.

2014-01-01

The contribution of oxidative stress to ischemic brain damage is well established. Nevertheless, for unknown reasons, several clinically tested antioxidant therapies failed to show benefits in human stroke. Based on our previous in vitro work, we hypothesized that the neuroprotective potency of antioxidants is related to their ability to limit release of the excitotoxic amino acids, glutamate and aspartate. We explored the effects of two antioxidants, tempol and edaravone, on amino acid release in the brain cortex, in a rat model of transient occlusion of the middle cerebral artery (MCAo). Amino acid levels were quantified using a microdialysis approach, with the probe positioned in the ischemic penumbra as verified by a laser Doppler technique. Two-hour MCAo triggered a dramatic increase in the levels of glutamate, aspartate, taurine and alanine. Microdialysate delivery of 10 mM tempol reduced the amino acid release by 60–80%, while matching levels of edaravone had no effect. In line with these latter data, an intracerebroventri-cular injection of tempol but not edaravone (500 nmols each, 15 minutes prior to MCAo) reduced infarction volumes by ~50% and improved neurobehavioral outcomes. In vitro assays showed that tempol was superior in removing superoxide anion, whereas edaravone was more potent in scavenging hydrogen peroxide, hydroxyl radical, and peroxynitrite. Overall, our data suggests that the neuroprotective properties of tempol are likely related to its ability to reduce tissue levels of the superoxide anion and pathological glutamate release, and, in such a way, limit progression of brain infarction within ischemic penumbra. These new findings may be instrumental in developing new antioxidant therapies for treatment of stroke. PMID:25224033

Cytosolic Nucleotides Block and Regulate the Arabidopsis Vacuolar Anion Channel AtALMT9*

PubMed Central

Zhang, Jingbo; Martinoia, Enrico; De Angeli, Alexis

2014-01-01

The aluminum-activated malate transporters (ALMTs) form a membrane protein family exhibiting different physiological roles in plants, varying from conferring tolerance to environmental Al3+ to the regulation of stomatal movement. The regulation of the anion channels of the ALMT family is largely unknown. Identifying intracellular modulators of the activity of anion channels is fundamental to understanding their physiological functions. In this study we investigated the role of cytosolic nucleotides in regulating the activity of the vacuolar anion channel AtALMT9. We found that cytosolic nucleotides modulate the transport activity of AtALMT9. This modulation was based on a direct block of the pore of the channel at negative membrane potentials (open channel block) by the nucleotide and not by a phosphorylation mechanism. The block by nucleotides of AtALMT9-mediated currents was voltage dependent. The blocking efficiency of intracellular nucleotides increased with the number of phosphate groups and ATP was the most effective cellular blocker. Interestingly, the ATP block induced a marked modification of the current-voltage characteristic of AtALMT9. In addition, increased concentrations of vacuolar anions were able to shift the ATP block threshold to a more negative membrane potential. The block of AtALMT9-mediated anion currents by ATP at negative membrane potentials acts as a gate of the channel and vacuolar anion tune this gating mechanism. Our results suggest that anion transport across the vacuolar membrane in plant cells is controlled by cytosolic nucleotides and the energetic status of the cell. PMID:25028514

Cytosolic nucleotides block and regulate the Arabidopsis vacuolar anion channel AtALMT9.

PubMed

Zhang, Jingbo; Martinoia, Enrico; De Angeli, Alexis

2014-09-12

The aluminum-activated malate transporters (ALMTs) form a membrane protein family exhibiting different physiological roles in plants, varying from conferring tolerance to environmental Al(3+) to the regulation of stomatal movement. The regulation of the anion channels of the ALMT family is largely unknown. Identifying intracellular modulators of the activity of anion channels is fundamental to understanding their physiological functions. In this study we investigated the role of cytosolic nucleotides in regulating the activity of the vacuolar anion channel AtALMT9. We found that cytosolic nucleotides modulate the transport activity of AtALMT9. This modulation was based on a direct block of the pore of the channel at negative membrane potentials (open channel block) by the nucleotide and not by a phosphorylation mechanism. The block by nucleotides of AtALMT9-mediated currents was voltage dependent. The blocking efficiency of intracellular nucleotides increased with the number of phosphate groups and ATP was the most effective cellular blocker. Interestingly, the ATP block induced a marked modification of the current-voltage characteristic of AtALMT9. In addition, increased concentrations of vacuolar anions were able to shift the ATP block threshold to a more negative membrane potential. The block of AtALMT9-mediated anion currents by ATP at negative membrane potentials acts as a gate of the channel and vacuolar anion tune this gating mechanism. Our results suggest that anion transport across the vacuolar membrane in plant cells is controlled by cytosolic nucleotides and the energetic status of the cell. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

Physiological levels of formate activate mitochondrial superoxide/hydrogen peroxide release from mouse liver mitochondria.

PubMed

Young, Adrian; Gardiner, Danielle; Brosnan, Margaret E; Brosnan, John T; Mailloux, Ryan J

2017-08-01

Here, we found that formate, an essential one-carbon metabolite, activates superoxide (O2·-)/hydrogen peroxide (H 2 O 2 ) release from mitochondria. Sodium formate (30 μm) induces a significant increase in O2·-/H 2 O 2 production in liver mitochondria metabolizing pyruvate (50 μm). At concentrations deemed to be toxic, formate does not increase O2·-/H 2 O 2 production further. It was observed that the formate-mediated increase in O2·-/H 2 O 2 production is not associated with cytochrome c oxidase (COX) inhibition or changes in membrane potential and NAD(P)H levels. Sodium formate supplementation increases phosphorylating respiration without altering proton leaks. Finally, it was observed that the 2-oxoglutarate dehydrogenase (OGDH) inhibitors 3-methyl-2-oxovaleric acid (KMV) and CPI-613 inhibit the formate-induced increase in pyruvate-driven ROS production. The importance of these findings in one-carbon metabolism and physiology are discussed herein. © 2017 Federation of European Biochemical Societies.

Altered binding of thioflavin t to the peripheral anionic site of acetylcholinesterase after phosphorylation of the active site by chlorpyrifos oxon or dichlorvos

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

Sultatos, L.G.; Kaushik, R.

2008-08-01

The peripheral anionic site of acetylcholinesterase, when occupied by a ligand, is known to modulate reaction rates at the active site of this important enzyme. The current report utilized the peripheral anionic site specific fluorogenic probe thioflavin t to determine if the organophosphates chlorpyrifos oxon and dichlorvos bind to the peripheral anionic site of human recombinant acetylcholinesterase, since certain organophosphates display concentration-dependent kinetics when inhibiting this enzyme. Incubation of 3 nM acetylcholinesterase active sites with 50 nM or 2000 nM inhibitor altered both the B{sub max} and K{sub d} for thioflavin t binding to the peripheral anionic site. However, thesemore » changes resulted from phosphorylation of Ser203 since increasing either inhibitor from 50 nM to 2000 nM did not alter further thioflavin t binding kinetics. Moreover, the organophosphate-induced decrease in B{sub max} did not represent an actual reduction in binding sites, but instead likely resulted from conformational interactions between the acylation and peripheral anionic sites that led to a decrease in the rigidity of bound thioflavin t. A drop in fluorescence quantum yield, leading to an apparent decrease in B{sub max}, would accompany the decreased rigidity of bound thioflavin t molecules. The organophosphate-induced alterations in K{sub d} represented changes in binding affinity of thioflavin t, with diethylphosphorylation of Ser203 increasing K{sub d}, and dimethylphosphorylation of Ser203 decreasing K{sub d}. These results indicate that chlorpyrifos oxon and dichlorvos do not bind directly to the peripheral anionic site of acetylcholinesterase, but can affect binding to that site through phosphorylation of Ser203.« less

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

PubMed Central

Hérouart, D; Van Montagu, M; Inzé, D

1994-01-01

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

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

PubMed

Hérouart, D; Van Montagu, M; Inzé, D

1994-03-01

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

Pharmacological Role of Anions (Sulphate, Nitrate, Oxalate and Acetate) on the Antibacterial Activity of Cobalt(II), Copper(II) and Nickel(II) Complexes With Nicotinoylhydrazine-Derived ONO, NNO and SNO Ligands

PubMed Central

Rauf, Abdur

1996-01-01

Mixed ligands biologically active complexes of cobalt(II), copper(II) and nickel(II) with nicotinoylhydrazine-derived ONO, NNO and SNO donor schiff-base ligands having the same metal ion but different anions such as sulphate, nitrate, oxalate and acetate have been synthesised and characterised on the basis of their physical, analytical and spectral data. In order to evaluate the role of anions on their bioability, these ligands and their synthesised metal complexes with various anions have been screened against bacterial species such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus and the title studies have proved a definative role of anions in increasing the biological activity PMID:18472896

Glutamate transporter-associated anion channels adjust intracellular chloride concentrations during glial maturation.

PubMed

Untiet, Verena; Kovermann, Peter; Gerkau, Niklas J; Gensch, Thomas; Rose, Christine R; Fahlke, Christoph

2017-02-01

Astrocytic volume regulation and neurotransmitter uptake are critically dependent on the intracellular anion concentration, but little is known about the mechanisms controlling internal anion homeostasis in these cells. Here we used fluorescence lifetime imaging microscopy (FLIM) with the chloride-sensitive dye MQAE to measure intracellular chloride concentrations in murine Bergmann glial cells in acute cerebellar slices. We found Bergmann glial [Cl - ] int to be controlled by two opposing transport processes: chloride is actively accumulated by the Na + -K + -2Cl - cotransporter NKCC1, and chloride efflux through anion channels associated with excitatory amino acid transporters (EAATs) reduces [Cl - ] int to values that vary upon changes in expression levels or activity of these channels. EAATs transiently form anion-selective channels during glutamate transport, and thus represent a class of ligand-gated anion channels. Age-dependent upregulation of EAATs results in a developmental chloride switch from high internal chloride concentrations (51.6 ± 2.2 mM, mean ± 95% confidence interval) during early development to adult levels (35.3 ± 0.3 mM). Simultaneous blockade of EAAT1/GLAST and EAAT2/GLT-1 increased [Cl - ] int in adult glia to neonatal values. Moreover, EAAT activation by synaptic stimulations rapidly decreased [Cl - ] int . Other tested chloride channels or chloride transporters do not contribute to [Cl - ] int under our experimental conditions. Neither genetic removal of ClC-2 nor pharmacological block of K + -Cl - cotransporter change resting Bergmann glial [Cl - ] int in acute cerebellar slices. We conclude that EAAT anion channels play an important and unexpected role in adjusting glial intracellular anion concentration during maturation and in response to cerebellar activity. GLIA 2017;65:388-400. © 2016 Wiley Periodicals, Inc.

A thermostable manganese-containing superoxide dismutase from the thermophilic fungus Thermomyces lanuginosus.

PubMed

Li, Duo-Chuan; Gao, Jing; Li, Ya-Ling; Lu, Jing

2005-02-01

A thermostable superoxide dismutase (SOD) from a Thermomyces lanuginosus strain (P134) was purified to homogeneity by fractional ammonium sulfate precipitation, ion-exchange chromatography on DEAE-Sepharose, Phenyl-Sepharose hydrophobic interaction chromatography, and gel filtration on Sephacryl S-100. The molecular mass of a single band of the enzyme was estimated to be 22.4 kDa, using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Using gel filtration on Sephacryl S-100, the molecular mass was estimated to be 89.1 kDa, indicating that this enzyme was composed of four identical subunits of 22.4 kDa each. The SOD was found to be inhibited by NaN3, but not by KCN or H2O2, suggesting that the SOD in T. lanuginosus was of the manganese superoxide dismutase type. The SOD exhibited maximal activity at pH 7.5. The optimum temperature for the activity was 55 degrees C. It was thermostable at 50 and 60 degrees C and retained 55% activity after 60 min at 70 degrees C. The half-life of the SOD at 80 degrees C was approximately 28 min and even retained 20% activity after 20 min at 90 degrees C.

Involvement of the chloroplast plastoquinone pool in the Mehler reaction.

PubMed

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

2017-09-01

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

Chemopreventive and Anticancer Activities of Allium victorialis var. platyphyllum Extracts

PubMed Central

Kim, Hyun-Jeong; Park, Min Jeong; Park, Hee-Juhn; Chung, Won-Yoon; Kim, Ki-Rim; Park, Kwang-Kyun

2014-01-01

Background: Allium victorialis var. platyphyllum is an edible perennial herb and has been used as a vegetable or as a Korean traditional medicine. Allium species have received much attention owing to their diverse pharmacological properties, including antioxidative, anti-inflammatory, and anticancer activities. However, A. victorialis var. platyphyllum needs more study. Methods: The chemopreventive potential of A. victorialis var. platyphyllum methanol extracts was examined by measuring 12-O-tetra-decanoylphorbol 13-acetate (TPA)-induced superoxide anion production in the differentiated HL-60 cells, TPA-induced mouse ear edema, and Ames/Salmonella mutagenicity. The apoptosis-inducing capabilities of the extracts were evaluated by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay, 4’,6-diamidino-2-phenylindole staining, and the DNA fragmentation assay in human colon cancer HT-29 cells. Antimetastatic activities of the extracts were also investigated in an experimental mouse lung metastasis model. Results: The methanol extracts of A. victorialis var. platyphyllum rhizome (AVP-R) and A. victorialis var. platyphyllum stem (AVP-S) dose-dependently inhibited the TPA-induced generation of superoxide anion in HL-60 cells and TPA-induced ear edema in mice, as well as 7,12-dimethylbenz[a]anthracene (DMBA) and tert-butyl hydroperoxide (t-BOOH) -induced bacterial mutagenesis. AVP-R and AVP-S reduced cell viability in a dose-related manner and induced apoptotic morphological changes and internucleosomal DNA fragmentation in HT-29 cells. In the experimental mouse lung metastasis model, the formation of tumor nodules in lung tissue was significantly inhibited by the treatment of the extracts. Conclusions: AVP-R and AVP-S possess antioxidative, anti-inflammatory, antimutagenic, proapoptotic, and antimetastatic activities. Therefore, these extracts can serve as a beneficial supplement for the prevention and treatment of cancer. PMID:25337587

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

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

Sheng, Yuewei; Gralla, Edith Butler; Schumacher, Mikhail

Reduction of superoxide (O{sub 2}{sup -}) by manganese-containing superoxide dismutase occurs through either a 'prompt protonation' pathway, or an 'inner-sphere' pathway, with the latter leading to formation of an observable Mn-peroxo complex. We recently reported that wild-type (WT) manganese superoxide dismutases (MnSODs) from Saccharomyces cerevisiae and Candida albicans are more gated toward the 'prompt protonation' pathway than human and bacterial MnSODs and suggested that this could result from small structural changes in the second coordination sphere of manganese. We report here that substitution of a second-sphere residue, Tyr34, by phenylalanine (Y34F) causes the MnSOD from S. cerevisiae to react exclusivelymore » through the 'inner-sphere' pathway. At neutral pH, we have a surprising observation that protonation of the Mn-peroxo complex in the mutant yeast enzyme occurs through a fast pathway, leading to a putative six-coordinate Mn3+ species, which actively oxidizes O{sub 2}{sup -} in the catalytic cycle. Upon increasing pH, the fast pathway is gradually replaced by a slow proton-transfer pathway, leading to the well-characterized five-coordinate Mn{sup 3+}. We here propose and compare two hypothetical mechanisms for the mutant yeast enzyme, diffeeing in the structure of the Mn-peroxo complex yet both involving formation of the active six-coordinate Mn{sup 3+} and proton transfer from a second-sphere water molecule, which has substituted for the -OH of Tyr34, to the Mn-peroxo complex. Because WT and the mutant yeast MnSOD both rest in the 2+ state and become six-coordinate when oxidized up from Mn{sup 2+}, six-coordinate Mn{sup 3+} species could also actively function in the mechanism of WT yeast MnSODs.« less

Evaluation of free radicals scavenging and immunity-modulatory activities of Purslane polysaccharides.

PubMed

YouGuo, Chen; ZongJi, Shen; XiaoPing, Chen

2009-12-01

In this study, antioxidant and immunity-modulatory activities of Purslane polysaccharide were estimated. The results revealed that in a dose-dependent manner, Purslane polysaccharides could significantly scavenge superoxide anion, 1,1-diphenyl-2-picrylhydrazyl (DPPH(-)), nitric oxide and hydroxyl radicals. Furthermore, the Purslane polysaccharides could still effectively inhibit the red blood cell (RBC) haemolysis, and increase spleen, thymocyte T and B lymphocyte proliferation, it could be concluded that Purslane polysaccharides could be of considerable preventive and therapeutic significance to some free radical associated health problems such as ovarian cancer, by scavenging accumulating free radicals and enhancing immunity functions.

Topical formulations with superoxide dismutase: influence of formulation composition on physical stability and enzymatic activity.

PubMed

Di Mambro, Valéria M; Borin, Maria F; Fonseca, Maria J V

2003-04-24

Three different topical formulations were supplemented with superoxide dismutase (SOD) and evaluated concerning physical and chemical stabilities in order to determine the most stable formulation that would maintain SOD activity. Physical stability was evaluated by storing the formulation at room temperature, and at 37 and 45 degrees C for 28 days. Samples were collected at 7-day intervals for assessment of rheological behavior. Chemical stability was evaluated by the measurement of enzymatic activity in formulations stored at room temperature and at 45 degrees C for 75 days. The formulations showed a pseudoplastic behavior, with a flow index of less than 1. There was no significant difference in the initial values of flow index, hysteresis loop or minimum apparent viscosity. The simple emulsion and the one stabilized with hydroxyethylcellulose showed decreased viscosity by the 21st day and with higher temperature, but no significant changes concerning the presence of SOD. Although there were no significant changes concerning storage time or temperature, the formulation stabilized with hydroxyethylcellulose showed a marked loss of SOD activity. The addition of SOD to the formulations studied did not affect their physical stability. Simple emulsions or emulsions stabilized with carboxypolymethylene seem to be better bases for enzyme addition than emulsion stabilized with hydroxyethylcellulose.

The effect of UV-B radiation on Bufo arenarum embryos survival and superoxide dismutase activity.

PubMed

Herkovits, J; D'Eramo, J L; Fridman, O

2006-03-01

The exposure of Bufo arenarum embryos to 300-310 nm UV-B at a dose of 4,104 Joule/m(2) resulted in 100% lethality within 24 hr while 820 Joule/m(2) was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m(2) at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 +/- 14.29, 74.5 +/- 13.19, 39.5 +/- 6.99 and 10.7 +/- 1.89 respectively while for control embryos it was 10.88 +/- 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure.

Characterization of Antisense Transformed Plants Deficient in the Tobacco Anionic Peroxidase.

PubMed

Lagrimini, L. M.; Gingas, V.; Finger, F.; Rothstein, S.; Liu, TTY.

1997-08-01

On the basis of the biological compounds that they metabolize, plant peroxidases have long been implicated in plant growth, cell wall biogenesis, lignification, and host defenses. Transgenic tobacco (Nicotiana tabacum L.) plants that underexpress anionic peroxidase were generated using antisense RNA. The antisense RNA was found to be specific for the anionic isoenzyme and highly effective, reducing endogenous transcript levels and total peroxidase activity by as much as 1600-fold. Antisense-transformed plants appeared normal at initial observation; however, growth studies showed that plants with reduced peroxidase activity grow taller and flower sooner than control plants. In contrast, previously transformed plants overproducing anionic peroxidase were shorter and flowered later than controls. Axillary buds were more developed in antisense-transformed plants and less developed in plants overproducing this enzyme. It was found that the lignin content in leaf, stem, and root was unchanged in antisense-transformed plants, which does not support a role for anionic peroxidase in the lignification of secondary xylem vessels. However, studies of wounded tissue show some reduction in wound-induced deposition of lignin-like polymers. The data support a possible role for tobacco anionic peroxidase in host defenses but not without a reduction in growth potential.

ABH antigens as recognition sites for the activation of red blood cell anion exchange by the lectin ulex europaeus agglutinin I.

PubMed

Engelmann, B

1993-11-01

The blood group antigen H (blood group O) and fucose-specific lectin Ulex europaeus agglutinin I (UEA1) (10 micrograms/ml) was found to increase the rate constant of Cl- efflux into 100 mM Na+ oxalate media by about 40% in erythrocytes taken from antigen H donors. In 100 mM K+ oxalate, 150 mM Na+ pyruvate and in 150 mM Na+ acetate media the lectin elevated the rate constant of Cl- efflux by 20-50%. The acceleration of Cl- efflux by UEA1 was completely blocked by 10 microM 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS) indicating that the effect of the lectin is mediated by the anion exchanger of human erythrocytes (band 3 protein). In antigen A1 erythrocytes no significant stimulation of anion exchange by UEA1 was seen. The activation of Cl- efflux was completely prevented by addition of 1 mM fucose to the medium. These results suggest that the effect of UEA1 is mediated through interaction with the fucose residues of H antigens. Increasing extracellular Ca++ from 0.5 to 5 mM in Na+ pyruvate or Na+ acetate media slightly reduced the acceleration of anion exchange by the lectin. On the other hand, replacing part of extracellular chloride by bicarbonate did not considerably alter the (previously reported) stimulatory effect of UEA1 on red blood cell Ca++ uptake. This suggests that the acceleration of anion exchange and of Ca++ uptake by UEA1, respectively, are mediated by different mechanisms. It is concluded that UEA1 activates anion exchange of human erythrocytes most probably by a direct interaction with H antigens present on extracellular domains of the band 3 protein.

Anion transport and supramolecular medicinal chemistry

DOE PAGES

Gale, Philip A.; Davis, Jeffery T.; Quesada, Roberto

2017-04-05

New approaches to the transmembrane transport of anions are discussed in this review. Advances in the design of small molecule anion carriers are reviewed in addition to advances in the design of synthetic anion channels. The application of anion transporters to the potential future treatment of disease is discussed in the context of recent findings on the selectivity of anion transporters.

Anion transport and supramolecular medicinal chemistry

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

Gale, Philip A.; Davis, Jeffery T.; Quesada, Roberto

New approaches to the transmembrane transport of anions are discussed in this review. Advances in the design of small molecule anion carriers are reviewed in addition to advances in the design of synthetic anion channels. The application of anion transporters to the potential future treatment of disease is discussed in the context of recent findings on the selectivity of anion transporters.

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

PubMed Central

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

2013-01-01

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

Assessing the reactivation efficacy of hydroxylamine anion towards VX-inhibited AChE: a computational study.

PubMed

Khan, Md Abdul Shafeeuulla; Ganguly, Bishwajit

2012-05-01

Oximate anions are used as potential reactivating agents for OP-inhibited AChE because of they possess enhanced nucleophilic reactivity due to the α-effect. We have demonstrated the process of reactivating the VX-AChE adduct with formoximate and hydroxylamine anions by applying the DFT approach at the B3LYP/6-311 G(d,p) level of theory. The calculated results suggest that the hydroxylamine anion is more efficient than the formoximate anion at reactivating VX-inhibited AChE. The reaction of formoximate anion and the VX-AChE adduct is a three-step process, while the reaction of hydroxylamine anion with the VX-AChE adduct seems to be a two-step process. The rate-determining step in the process is the initial attack on the VX of the VX-AChE adduct by the nucleophile. The subsequent steps are exergonic in nature. The potential energy surface (PES) for the reaction of the VX-AChE adduct with hydroxylamine anion reveals that the reactivation process is facilitated by the lower free energy of activation (by a factor of 1.7 kcal mol(-1)) than that of the formoximate anion at the B3LYP/6-311 G(d,p) level of theory. The higher free energy of activation for the reverse reactivation reaction between hydroxylamine anion and the VX-serine adduct further suggests that the hydroxylamine anion is a very good antidote agent for the reactivation process. The activation barriers calculated in solvent using the polarizable continuum model (PCM) for the reactivation of the VX-AChE adduct with hydroxylamine anion were also found to be low. The calculated results suggest that V-series compounds can be more toxic than G-series compounds, which is in accord with earlier experimental observations.

Superoxide radical-generating compounds activate a predicted promoter site for paraquat-inducible genes of the Chromobacterium violaceum bacterium in a dose-dependent manner.

PubMed

Gabriel, J E; Guerra-Slompo, E P; de Souza, E M; de Carvalho, F A L; Madeira, H M F; de Vasconcelos, A T R

2015-08-21

The purpose of the present study was to functionally evaluate the influence of superoxide radical-generating compounds on the heterologous induction of a predicted promoter region of open reading frames for paraquat-inducible genes (pqi genes) revealed during genome annotation analyses of the Chromobacterium violaceum bacterium. A 388-bp fragment corresponding to a pqi gene promoter of C. violaceum was amplified using specific primers and cloned into a conjugative vector containing the Escherichia coli lacZ gene without a promoter. Assessments of the expression of the β-galactosidase enzyme were performed in the presence of menadione (MEN) and phenazine methosulfate (PMS) compounds at different final concentrations to evaluate the heterologous activation of the predicted promoter region of interest in C. violaceum induced by these substrates. Under these experimental conditions, the MEN reagent promoted highly significant increases in the expression of the β-galactosidase enzyme modulated by activating the promoter region of the pqi genes at all concentrations tested. On the other hand, significantly higher levels in the expression of the β-galactosidase enzyme were detected exclusively in the presence of the PMS reagent at a final concentration of 50 μg/mL. The findings described in the present study demonstrate that superoxide radical-generating compounds can activate a predicted promoter DNA motif for pqi genes of the C. violaceum bacterium in a dose-dependent manner.

Evidence for anionic redox activity in a tridimensional-ordered Li-rich positive electrode β-Li2IrO3

NASA Astrophysics Data System (ADS)

Pearce, Paul E.; Perez, Arnaud J.; Rousse, Gwenaelle; Saubanère, Mathieu; Batuk, Dmitry; Foix, Dominique; McCalla, Eric; Abakumov, Artem M.; van Tendeloo, Gustaaf; Doublet, Marie-Liesse; Tarascon, Jean-Marie

2017-05-01

Lithium-ion battery cathode materials have relied on cationic redox reactions until the recent discovery of anionic redox activity in Li-rich layered compounds which enables capacities as high as 300 mAh g-1. In the quest for new high-capacity electrodes with anionic redox, a still unanswered question was remaining regarding the importance of the structural dimensionality. The present manuscript provides an answer. We herein report on a β-Li2IrO3 phase which, in spite of having the Ir arranged in a tridimensional (3D) framework instead of the typical two-dimensional (2D) layers seen in other Li-rich oxides, can reversibly exchange 2.5 e- per Ir, the highest value ever reported for any insertion reaction involving d-metals. We show that such a large activity results from joint reversible cationic (Mn+) and anionic (O2)n- redox processes, the latter being visualized via complementary transmission electron microscopy and neutron diffraction experiments, and confirmed by density functional theory calculations. Moreover, β-Li2IrO3 presents a good cycling behaviour while showing neither cationic migration nor shearing of atomic layers as seen in 2D-layered Li-rich materials. Remarkably, the anionic redox process occurs jointly with the oxidation of Ir4+ at potentials as low as 3.4 V versus Li+/Li0, as equivalently observed in the layered α-Li2IrO3 polymorph. Theoretical calculations elucidate the electrochemical similarities and differences of the 3D versus 2D polymorphs in terms of structural, electronic and mechanical descriptors. Our findings free the structural dimensionality constraint and broaden the possibilities in designing high-energy-density electrodes for the next generation of Li-ion batteries.

Production and actions of superoxide in the renal medulla.

PubMed

Zou, A P; Li, N; Cowley, A W

2001-02-01

The present study characterized the biochemical pathways responsible for superoxide (O(2)(-.)) production in different regions of the rat kidney and determined the role of O(2)(-.)in the control of renal medullary blood flow (MBF) and renal function. By use of dihydroethidium/DNA fluorescence spectrometry with microtiter plates, the production of O(2)(-. )was monitored when tissue homogenate from different kidney regions was incubated with substrates for the major O(2)(-.)-producing enzymes, such as NADH/NADPH oxidase, xanthine oxidase, and mitochondrial respiratory chain enzymes. The production of O(2)(-. )via NADH oxidase was greater (P<0.05) in the renal cortex and outer medulla (OM) than in the papilla. The mitochondrial enzyme activity for O(2)(-.)production was higher (P<0.05) in the OM than in the cortex and papilla. Compared with NADH oxidase and mitochondrial enzymes, xanthine oxidase and NADPH oxidase produced much less O(2)(-. )in the kidney under this condition. Overall, the renal OM exhibited the greatest enzyme activities for O(2)(-.)production. In anesthetized rats, renal medullary interstitial infusion of a superoxide dismutase inhibitor, diethyldithiocarbamate, markedly decreased renal MBF and sodium excretion. Diethyldithiocarbamate (5 mg/kg per minute by renal medullary interstitial infusion [RI]) reduced the renal medullary laser-Doppler flow signal from 0.6+/-0.04 to 0.4+/-0.03 V, a reduction of 33%, and both urine flow and sodium excretion decreased by 49%. In contrast, a membrane-permeable superoxide dismutase mimetic, 4-hydroxytetramethyl-piperidine-1-oxyl (TEMPOL, 30 micromol/kg per minute RI) increased MBF and sodium excretion by 34% and 69%, respectively. These effects of TEMPOL on renal MBF and sodium excretion were not altered by pretreatment with N(G)-nitro-L-arginine methyl ester (10 microgram/kg per minute RI). We conclude that (1) renal medullary O(2)(-. )is primarily produced in the renal OM; (2) both NADH oxidase and mitochondrial

Cation–Anion Interactions within the Nucleic Acid Ion Atmosphere Revealed by Ion Counting

PubMed Central

Gebala, Magdalena; Giambasu, George M.; Lipfert, Jan; Bisaria, Namita; Bonilla, Steve; Li, Guangchao; York, Darrin M.; Herschlag, Daniel

2016-01-01

The ion atmosphere is a critical structural, dynamic, and energetic component of nucleic acids that profoundly affects their interactions with proteins and ligands. Experimental methods that “count” the number of ions thermodynamically associated with the ion atmosphere allow dissection of energetic properties of the ion atmosphere, and thus provide direct comparison to theoretical results. Previous experiments have focused primarily on the cations that are attracted to nucleic acid polyanions, but have also showed that anions are excluded from the ion atmosphere. Herein, we have systematically explored the properties of anion exclusion, testing the zeroth-order model that anions of different identity are equally excluded due to electrostatic repulsion. Using a series of monovalent salts, we find, surprisingly, that the extent of anion exclusion and cation inclusion significantly depends on salt identity. The differences are prominent at higher concentrations and mirror trends in mean activity coefficients of the electrolyte solutions. Salts with lower activity coefficients exhibit greater accumulation of both cations and anions within the ion atmosphere, strongly suggesting that cation–anion correlation effects are present in the ion atmosphere and need to be accounted for to understand electrostatic interactions of nucleic acids. To test whether the effects of cation–anion correlations extend to nucleic acid kinetics and thermodynamics, we followed the folding of P4–P6, a domain of the Tetrahymena group I ribozyme, via single-molecule fluorescence resonance energy transfer in solutions with different salts. Solutions of identical concentration but lower activity gave slower and less favorable folding. Our results reveal hitherto unknown properties of the ion atmosphere and suggest possible roles of oriented ion pairs or anion-bridged cations in the ion atmosphere for electrolyte solutions of salts with reduced activity. Consideration of these new

Endotoxin treatment protects rats against ozone-induced lung edema: with evidence for the role of manganese superoxide dismutase

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

Rahman, I.; Massaro, D.

Ozone is a strong oxidizing agent that can cause lung damage and edema. There is evidence that it does so by causing peroxidation of membrane lipids. However, the elevation in lung activity of copper, zinc superoxide dismutase (Cu, ZnSOD), and manganese superoxide dismutase (MnSOD) during exposure to ozone suggests that increased production of superoxide could contribute to lung edema caused by ozone. This latter observation, and preliminary evidence that treatment of rats with endotoxin elevates lung activity of MnSOD without elevation of the activity of Cu, ZnSOD, catalase (CAT), or glutathione peroxidase (GP), led to the present study. We treatedmore » rats with endotoxin, exposed them to different concentrations of ozone, measured lung wet weight to dry weight ratio, thiobarbituric acid-reactive material (TBAR), and assayed lung tissue for Cu, ZnSOD, MnSOD, CAT, and GP activity. Our major findings are, (1) a strongly edemogenic concentration of ozone-lowered MnSOD activity; (2) endotoxin treatment of air-breathing rats did not decrease lipid peroxidation as indicated by the lung concentration of TBAR; (3) induction of increased MnSOD activity in lung by treatment with endotoxin was associated with virtually complete protection against an otherwise edemogenic concentration of ozone, with less lipid peroxidation, and with less loss of weight; and (4) this protection occurred without elevated Cu, ZnSOD, CAT, or GP activity.« less

Effects of quercetin on heart nitric oxide metabolism in l-NAME treated rats.

PubMed

Calabró, Valeria; Litterio, María C; Fraga, Cesar G; Galleano, Monica; Piotrkowski, Barbara

2018-06-01

This study investigated the effects of a quercetin-supplemented diet on the biochemical changes installed in the heart of NO-deficient rats in terms of oxidants production and NO bioavailability determinants. Sprague-Dawley rats were subjected to N ω -nitro-l-arginine methyl ester (l-NAME) treatment (360 mg/L l-NAME in the drinking water, 4 d) with or without supplementation with quercetin (4 g/kg diet). l-NAME administration led to increased blood pressure (BP) (30%), decreased nitric oxide synthase (NOS) activity (50%), and increases in NADPH oxidase (NOX)-dependent superoxide anion production (60%) and p47 phox protein level (65%). The co-administration of quercetin prevented the increase in BP and the activation of NOX but did not modify the decrease in NOS activity caused by l-NAME. In addition, quercetin affected oxidative stress parameters as glutathione oxidation, and the activities of oxidant detoxifying enzymes superoxide dismutase, glutathione peroxidase, and catalase. Thus, quercetin administration counteracts l-NAME effects on NO bioavailability determinants in vivo, essentially through controlling NOX-mediated superoxide anion production. Copyright © 2018. Published by Elsevier Inc.

Targeting the superoxide/nitric oxide ratio by L-arginine and SOD mimic in diabetic rat skin.

PubMed

Jankovic, Aleksandra; Ferreri, Carla; Filipovic, Milos; Ivanovic-Burmazovic, Ivana; Stancic, Ana; Otasevic, Vesna; Korac, Aleksandra; Buzadzic, Biljana; Korac, Bato

2016-11-01

Setting the correct ratio of superoxide anion (O 2 •- ) and nitric oxide ( • NO) radicals seems to be crucial in restoring disrupted redox signaling in diabetic skin and improvement of • NO physiological action for prevention and treatment of skin injuries in diabetes. In this study we examined the effects of L-arginine and manganese(II)-pentaazamacrocyclic superoxide dismutase (SOD) mimic - M40403 in diabetic rat skin. Following induction of diabetes by alloxan (blood glucose level ≥12 mMol l  -1 ) non-diabetic and diabetic male Mill Hill hybrid hooded rats were divided into three subgroups: (i) control, and receiving: (ii) L-arginine, (iii) M40403. Treatment of diabetic animals started after diabetes induction and lasted for 7 days. Compared to control, lower cutaneous immuno-expression of endothelial NO synthase (eNOS), heme oxygenase 1 (HO1), manganese SOD (MnSOD) and glutathione peroxidase (GSH-Px), in parallel with increased NFE2-related factor 2 (Nrf2) and nitrotyrosine levels characterized diabetic skin. L-arginine and M40403 treatments normalized alloxan-induced increase in nitrotyrosine. This was accompanied by the improvement/restitution of eNOS and HO1 or MnSOD and GSH-Px protein expression levels in diabetic skin following L-arginine, i.e. SOD mimic treatments, respectively. The results indicate that L-arginine and M40403 stabilize redox balance in diabetic skin and suggest the underlying molecular mechanisms. Restitution of skin redox balance by L-arginine and M40403 may represent an effective strategy to ameliorate therapy of diabetic skin.

Bipyrrole-Strapped Calix[4]pyrroles: Strong Anion Receptors That Extract the Sulfate Anion

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

Kim, Sung Kuk; Lee, Juhoon; Williams, Neil J

Cage-type calix[4]pyrroles 2 and 3 bearing two additional pyrrole groups on the strap have been synthesized. Compared with the parent calix[4]pyrrole (1), they were found to exhibit remarkably enhanced affinities for anions, including the sulfate anion (TBA+ salts), in organic media (CD2Cl2). This increase is ascribed to participation of the bipyrrole units in anion binding. Receptors 2 and 3 extract the hydrophilic sulfate anion (as the methyltrialkyl(C8-10)ammonium (A336+) salt)) from aqueous media into a chloroform phase with significantly improved efficiency (>10-fold relative to calix[4]pyrrole 1). These two receptors also solubilize into chloroform the otherwise insoluble sulfate salt, (TMA)2SO4 (tetramethylammonium sulfate).

Endogenous flow-induced superoxide stimulates Na/H exchange activity via PKC in thick ascending limbs

PubMed Central

Garvin, Jeffrey L.

2014-01-01

Luminal flow stimulates Na reabsorption along the nephron and activates protein kinase C (PKC) which enhances endogenous superoxide (O2−) production by thick ascending limbs (TALs). Exogenously-added O2− augments TAL Na reabsorption, a process also dependent on PKC. Luminal Na/H exchange (NHE) mediates NaHCO3 reabsorption. However, whether flow-stimulated, endogenously-produced O2− enhances luminal NHE activity and the signaling pathway involved are unclear. We hypothesized that flow-induced production of endogenous O2− stimulates luminal NHE activity via PKC in TALs. Intracellular pH recovery was measured as an indicator of NHE activity in isolated, perfused rat TALs. Increasing luminal flow from 5 to 20 nl/min enhanced total NHE activity from 0.104 ± 0.031 to 0.167 ± 0.036 pH U/min, 81%. The O2− scavenger tempol decreased total NHE activity by 0.066 ± 0.011 pH U/min at 20 nl/min but had no significant effect at 5 nl/min. With the NHE inhibitor EIPA in the bath to block basolateral NHE, tempol reduced flow-enhanced luminal NHE activity by 0.029 ± 0.010 pH U/min, 30%. When experiments were repeated with staurosporine, a nonselective PKC inhibitor, tempol had no effect. Because PKC could mediate both induction of O2− by flow and the effect of O2− on luminal NHE activity, we used hypoxanthine/xanthine oxidase to elevate O2−. Hypoxanthine/xanthine oxidase increased luminal NHE activity by 0.099 ± 0.020 pH U/min, 137%. Staurosporine and the PKCα/β1-specific inhibitor Gö6976 blunted this effect. We conclude that flow-induced O2− stimulates luminal NHE activity in TALs via PKCα/β1. This accounts for part of flow-stimulated bicarbonate reabsorption by TALs. PMID:25080525

Anti-oxidative and photo-protective effects of coumarins isolated from Fraxinus chinensis.

PubMed

Lee, Bum-Chun; Lee, So Yong; Lee, Hwa Jeong; Sim, Gwan-Sub; Kim, Jin-Hui; Kim, Jin-Hwa; Cho, Young-Ho; Lee, Dong-Hwan; Pyo, Hyeong-Bae; Choe, Tae-Boo; Moon, Dong Cheul; Yun, Yeo Pyo; Hong, Jin Tae

2007-10-01

Free radicals and reactive oxygen species (ROS), which are generated by UV irradiation, may cause serious injury to skin cell membranes, DNA and functional proteins. In addition, these agents stimulate the expressions of matrix metalloproteinases (MMPs), which can degrade most components of the extracellular matrix (ECM), including collagen. In order to develop new anti-photoaging agents, five major components from the extract of Fraxinus chinensis extract (FCE) were identified. Two of the major components of FCE were found to be esculin (11.2%) and esculetin (1.9%). FCE (IC50: 50.0 microg/mL 1, 1-diphenyl-2-picrylhydrazyl (DPPH); 19.8 microg/mL, superoxide anion radical) and esculetin (IC50: 2.1 microg/mL DPPH; 0.6 microg/mL, superoxide anion radical) showed strong antioxidative activities. Of the compounds tested, esculetin showed the strongest scavenging activity against DPPH radicals, followed by superoxide anions from the xanthine/xanthine oxidase system. The intracellular ROS scavenging activity showed that oxidation of 5-(6-)-chloromethyl-2', 7'-dichlorodihydrofluorescein diacetate (CM-H2DCFDA) was effectively inhibited by esculetin, with potent free radical scavenging activity was also shown in UVB-irradiated human dermal fibroblasts (HDFs). Moreover, treatment of UVA-irradiated HDFs with esculetin resulted in dose-dependent decreases in the expression levels of MMP-1 mRNA and protein. From these results, FCE and one of its components, esculetin, were predicted to be potentially useful as ingredients in cosmetics for protecting against photoaging.

Characterization of Antisense Transformed Plants Deficient in the Tobacco Anionic Peroxidase.

PubMed Central

Lagrimini, L. M.; Gingas, V.; Finger, F.; Rothstein, S.; Liu, TTY.

1997-01-01

On the basis of the biological compounds that they metabolize, plant peroxidases have long been implicated in plant growth, cell wall biogenesis, lignification, and host defenses. Transgenic tobacco (Nicotiana tabacum L.) plants that underexpress anionic peroxidase were generated using antisense RNA. The antisense RNA was found to be specific for the anionic isoenzyme and highly effective, reducing endogenous transcript levels and total peroxidase activity by as much as 1600-fold. Antisense-transformed plants appeared normal at initial observation; however, growth studies showed that plants with reduced peroxidase activity grow taller and flower sooner than control plants. In contrast, previously transformed plants overproducing anionic peroxidase were shorter and flowered later than controls. Axillary buds were more developed in antisense-transformed plants and less developed in plants overproducing this enzyme. It was found that the lignin content in leaf, stem, and root was unchanged in antisense-transformed plants, which does not support a role for anionic peroxidase in the lignification of secondary xylem vessels. However, studies of wounded tissue show some reduction in wound-induced deposition of lignin-like polymers. The data support a possible role for tobacco anionic peroxidase in host defenses but not without a reduction in growth potential. PMID:12223765

Increased survival of skin flaps by scavengers of superoxide radical

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

Huang, L.; Privalle, C.T.; Serafin, D.

1987-08-01

Elevation of rat abdominal skin flaps, followed by ligation and division of the left inferior neurovascular pedicle, resulted in only a 40% survival of the area normally perfused by the ligated artery and vein. Superoxide dismutase (SOD) (EC1.15.1.1) administered v (20,000 U/kg) 30 min before flap elevation increased survival to 52%. SOD derivatized with polyethylene gycol, which increases circulating half-life, was more effective, increasing survival to 80%. This protective effect resulted from the catalytic activity of the derivatized enzyme because inactivation by treatment with H/sub 2/O/sub 2/ eliminated its effect on skin flap survival. An equimolar mixture of Desferal andmore » MnCl/sub 2/, which catalyzes the dismutation of O/sub 2//sup -/ in vitro, improved survival to 72%. Desferal-Fe/sup 3 +/, which lacks in vitro SOD activity, or Mn/sup 2 +/ alone did not affect the survival of skin flaps, but Desferal alone was nearly as effective as the Desferal-Mn/sup 2 +/ mixture. This effect of Desferal may result from acquisition of and subsequent removal of iron in vivo. These results support the view that the superoxide radical or a product derived from it plays a role in limiting the survival of island skin flaps.« less

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

PubMed

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

2013-01-01

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

Mechanisms for activating Cu- and Zn-containing superoxide dismutase in the absence of the CCS Cu chaperone.

PubMed

Carroll, Mark C; Girouard, Jody B; Ulloa, Janella L; Subramaniam, Jamuna R; Wong, Phillip C; Valentine, Joan Selverstone; Culotta, Valeria Cizewski

2004-04-20

The Cu- and Zn-containing superoxide dismutase 1 (SOD1) largely obtains Cu in vivo by means of the action of the Cu chaperone CCS. Yet, in the case of mammalian SOD1, a secondary pathway of activation is apparent. Specifically, when human SOD1 is expressed in either yeast or mammalian cells that are null for CCS, the SOD1 enzyme retains a certain degree of activity. This CCS-independent activity is evident with both wild-type and mutant variants of SOD1 that have been associated with familial amyotrophic lateral sclerosis. We demonstrate here that the CCS-independent activation of mammalian SOD1 involves glutathione, particularly the reduced form, or GSH. A role for glutathione in CCS-independent activation was seen with human SOD1 molecules that were expressed in either yeast cells or immortalized fibroblasts. Compared with mammalian SOD1, the Saccharomyces cerevisiae enzyme cannot obtain Cu without CCS in vivo, and this total dependence on CCS involves the presence of dual prolines near the C terminus of the SOD1 polypeptide. Indeed, the insertion of such prolines into human SOD1 rendered this molecule refractory to CCS-independent activation. The possible implications of multiple pathways for SOD1 activation are discussed in the context of SOD1 evolutionary biology and familial amyotrophic lateral sclerosis.

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

PubMed

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

1992-01-01

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

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

PubMed Central

Herkovits, J.; D’Eramo, J. L.; Fridman, O.

2006-01-01

The exposure of Bufo arenarum embryos to 300–310 nm UV-B at a dose of 4,104 Joule/m2 resulted in 100% lethality within 24 hr while 820 Joule/m2 was the NOEC value for short-term chronic (10 days) exposure. The dose response curves show that lethal effects are proportional with the dose and achieve its highest value within 48 hr post exposure. The superoxide dismutase (SOD) activity in amphibian embryos for sublethal UV-B exposures was evaluated by means of UV-B treatments with 273 (A), 820(B), 1368(C) and 1915(D) Joule/m2 at 2 and 5 hours post irradiation. The SOD activity in units/mg protein in A, B, C and D at 2 hr after treatments were 80.72 ± 14.29, 74.5 ± 13.19, 39.5 ± 6.99 and 10.7 ± 1.89 respectively while for control embryos it was 10.88 ± 1.31. At 5 hr after treatments the SOD values were similar to those found in control embryos. The results confirm the high susceptibility of amphibian embryos to UV-B and point out that the SOD activity is enhanced by low doses of UV-B irradiation achieving significantly higher values than in control embryos at 2 hr post exposure. PMID:16823076

Study on the free radical scavenging activity of sea cucumber (Paracaudina chinens var.) gelatin hydrolysate

NASA Astrophysics Data System (ADS)

Zeng, Mingyong; Xiao, Feng; Zhao, Yuanhui; Liu, Zunying; Li, Bafang; Dong, Shiyuan

2007-07-01

Gelatin from the sea cucumber (Paracaudina chinens var.) was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff (MWCO). The portion (less than 5 kDa) was further separated by Sephadex G-25. The active peak was collected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals (O2·-) and hydroxyl radicals (·OH) of the fraction with the highest activity were 29.02% and 75.41%, respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria.

The preparation of calcium superoxide from calcium peroxide diperoxyhydrate

NASA Technical Reports Server (NTRS)

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

1977-01-01

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

Effect of probiotics enriched diet on Paralichthys olivaceus infected with lymphocystis disease virus (LCDV).

PubMed

Harikrishnan, Ramasamy; Balasundaram, Chellam; Heo, Moon-Soo

2010-11-01

We report the effect of two probiotics, Lactobacil and Sporolac as separate or mixed diets on innate immune mechanisms, such as phagocytosis activity, superoxide anion production of blood leukocytes, complement activity and plasma lysozyme activity, and disease resistance in lymphocystis disease virus (LCDV) infected olive flounder, Paralichthys olivaceus (523.5 +/- 18.3 g) on week 1, 2, and 4. In infected fish, administration of diet supplemented with Lactobacil individually or mixed with Sporolac significantly enhanced the immune parameters like phagocytic activity superoxide anion production, complement activity, and plasma lysozyme. However administration of supplemented diet with Sporolac alone, all the chosen immune parameters did not enhance when compared to control group; this diets resulted in lower mortality (30% and 25%) than Sporolac diet group (45%) in 30 days. We conclude that Lactobacil individually or mixed with Sporolac act as immunostimulants that enhance the innate immune response and disease resistance in lymphocystis disease virus (LCDV) infected olive flounder. Published by Elsevier Ltd.

Highly Dynamic Anion-Quadrupole Networks in Proteins.

PubMed

Kapoor, Karan; Duff, Michael R; Upadhyay, Amit; Bucci, Joel C; Saxton, Arnold M; Hinde, Robert J; Howell, Elizabeth E; Baudry, Jerome

2016-11-01

The dynamics of anion-quadrupole (or anion-π) interactions formed between negatively charged (Asp/Glu) and aromatic (Phe) side chains are for the first time computationally characterized in RmlC (Protein Data Bank entry 1EP0 ), a homodimeric epimerase. Empirical force field-based molecular dynamics simulations predict anion-quadrupole pairs and triplets (anion-anion-π and anion-π-π) are formed by the protein during the simulated trajectory, which suggests that the anion-quadrupole interactions may provide a significant contribution to the overall stability of the protein, with an average of -1.6 kcal/mol per pair. Some anion-π interactions are predicted to form during the trajectory, extending the number of anion-quadrupole interactions beyond those predicted from crystal structure analysis. At the same time, some anion-π pairs observed in the crystal structure exhibit marginal stability. Overall, most anion-π interactions alternate between an "on" state, with significantly stabilizing energies, and an "off" state, with marginal or null stabilizing energies. The way proteins possibly compensate for transient loss of anion-quadrupole interactions is characterized in the RmlC aspartate 84-phenylalanine 112 anion-quadrupole pair observed in the crystal structure. A double-mutant cycle analysis of the thermal stability suggests a possible loss of anion-π interactions compensated by variations of hydration of the residues and formation of compensating electrostatic interactions. These results suggest that near-planar anion-quadrupole pairs can exist, sometimes transiently, which may play a role in maintaining the structural stability and function of the protein, in an otherwise very dynamic interplay of a nonbonded interaction network as well as solvent effects.

ESI activity of Br⁻, BF₄⁻ , ClO₄⁻ and BPh₄⁻ anions in the presence of Li⁺ and NBu⁴⁺ counter-ions.

PubMed

Koszinowski, K; Lissy, F

2017-03-01

To improve our understanding of the electrospray ionization (ESI) process, we have subjected equimolar mixtures of salts A + X - (A +  = Li + , NBu 4 + ; X -  = Br - , ClO 4 - , BF 4 - , BPh 4 - ) in different solvents (CH 3 CN, tetrahydrofuran, CH 3 OH, H 2 O) to negative-ion mode ESI and analyzed the relative ESI activity of the different anionic model analytes. The ESI activity of the large and hydrophobic BPh 4 - ion greatly exceeds that of the smaller and more hydrophilic anions Br - , ClO 4 - and BF 4 - , which we ascribe to its higher surface activity. Moreover, the ESI activity of the anions is modulated by the action of the counter-ions and their different tendency toward ion pairing. The tendency toward ion pairing can be reduced by the addition of the chelating ligands 12-crown-4 and 2.2.1 cryptand and is, although to a smaller degree, further influenced by the variation of the solvent. Complementary electrical conductivity measurements afford additional information on the interactions of the ionic constituents of the sample solutions. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Superoxide Dismutase in Ripening Fruits

PubMed Central

Baker, James Earl

1976-01-01

The levels of superoxide dismutase (SOD) activity in extracts of preclimacteric apple, banana, avocado, and tomato fruits were not greatly different than in extracts of postclimacteric fruits. The results indicate that no major quantitative change in SOD occurs in fruits with or preceding the onset of senescence. Tomato fruit SOD was studied in more detail, and was found largely in the soluble fraction, and to a lesser extent in the mitochondrial and plastid fractions. The soluble fraction was purified by ammonium sulfate fractionation, column chromatography, and isoelectric focusing. Isoelectric focusing separated SOD from contaminating peroxidases. The purified tomato SOD showed an apparent molecular weight of 31,500 determined by gel filtration. Polyacrylamide gel electrophoresis of this preparation indicated two SOD components corresponding to two protein bands, one of which stained more intensely than the other. The purified tomato enzyme was inhibited 90% by 1 mm KCN. PMID:16659735

Superoxide dismutase in ripening fruits.

PubMed

Baker, J E

1976-11-01

The levels of superoxide dismutase (SOD) activity in extracts of preclimacteric apple, banana, avocado, and tomato fruits were not greatly different than in extracts of postclimacteric fruits. The results indicate that no major quantitative change in SOD occurs in fruits with or preceding the onset of senescence. Tomato fruit SOD was studied in more detail, and was found largely in the soluble fraction, and to a lesser extent in the mitochondrial and plastid fractions. The soluble fraction was purified by ammonium sulfate fractionation, column chromatography, and isoelectric focusing. Isoelectric focusing separated SOD from contaminating peroxidases. The purified tomato SOD showed an apparent molecular weight of 31,500 determined by gel filtration. Polyacrylamide gel electrophoresis of this preparation indicated two SOD components corresponding to two protein bands, one of which stained more intensely than the other. The purified tomato enzyme was inhibited 90% by 1 mm KCN.

Hydration of a Large Anionic Charge Distribution - Naphthalene-Water Cluster Anions

NASA Astrophysics Data System (ADS)

Weber, J. Mathias; Adams, Christopher L.

2010-06-01

We report the infrared spectra of anionic clusters of naphthalene with up to three water molecules. Comparison of the experimental infrared spectra with theoretically predicted spectra from quantum chemistry calculations allow conclusions regarding the structures of the clusters under study. The first water molecule forms two hydrogen bonds with the π electron system of the naphthalene moiety. Subsequent water ligands interact with both the naphthalene and the other water ligands to form hydrogen bonded networks, similar to other hydrated anion clusters. Naphthalene-water anion clusters illustrate how water interacts with negative charge delocalized over a large π electron system. The clusters are interesting model systems that are discussed in the context of wetting of graphene surfaces and polyaromatic hydrocarbons.

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

PubMed

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

2018-05-07

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

Free cholesterol accumulation impairs antioxidant activities and aggravates apoptotic cell death in menadione-induced oxidative injury.

PubMed

Lee, Waisin; Xu, Mingjing; Li, Yue; Gu, Yong; Chen, Jianping; Wong, Derek; Fung, Peter C W; Shen, Jiangang

2011-10-01

Although the relationship between hypercholesterolemia and oxidative stress has been extensively investigated, direct evidence regarding to the roles of cholesterol accumulation in the generations of reactive oxygen species (ROS) and apoptotic cell death under oxidative stress is lack. In this study, we investigated productions of superoxide anions (O(2)(-)) and nitric oxide (NO), and apoptotic cell death in wild type Chinese hamster ovary (CHO) cells and cholesterol accumulated CHO cells genetically and chemically. Oxidative stress was induced by menadione challenge. The results revealed that abundance of free cholesterol (FC) promoted menadione-induced O(2)(-) and NO productions. FC accumulation down-regulated eNOS expression but up-regulated NADPH oxidases, and inhibited the activities of superoxide dismutase (SOD) and catalase. Treatment of menadione increased the expressions of iNOS and qp91 phox, enhanced the activities of SOD and catalase in the wild-type CHO cells but inhibited the activity of glutathione peroxidase in the cholesterol accumulated CHO cells. Moreover, FC abundance promoted apoptotic cell death in these cells. Taken together, those results suggest that free cholesterol accumulation aggravates menadione-induced oxidative stress and exacerbates apoptotic cell death. Copyright © 2011 Elsevier Inc. All rights reserved.

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

NASA Astrophysics Data System (ADS)

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.

Evidence for anionic redox activity in a tridimensional-ordered Li-rich positive electrode β-Li2IrO3.

PubMed

Pearce, Paul E; Perez, Arnaud J; Rousse, Gwenaelle; Saubanère, Mathieu; Batuk, Dmitry; Foix, Dominique; McCalla, Eric; Abakumov, Artem M; Van Tendeloo, Gustaaf; Doublet, Marie-Liesse; Tarascon, Jean-Marie

2017-05-01

Lithium-ion battery cathode materials have relied on cationic redox reactions until the recent discovery of anionic redox activity in Li-rich layered compounds which enables capacities as high as 300 mAh g -1 . In the quest for new high-capacity electrodes with anionic redox, a still unanswered question was remaining regarding the importance of the structural dimensionality. The present manuscript provides an answer. We herein report on a β-Li 2 IrO 3 phase which, in spite of having the Ir arranged in a tridimensional (3D) framework instead of the typical two-dimensional (2D) layers seen in other Li-rich oxides, can reversibly exchange 2.5 e - per Ir, the highest value ever reported for any insertion reaction involving d-metals. We show that such a large activity results from joint reversible cationic (M n+ ) and anionic (O 2 ) n- redox processes, the latter being visualized via complementary transmission electron microscopy and neutron diffraction experiments, and confirmed by density functional theory calculations. Moreover, β-Li 2 IrO 3 presents a good cycling behaviour while showing neither cationic migration nor shearing of atomic layers as seen in 2D-layered Li-rich materials. Remarkably, the anionic redox process occurs jointly with the oxidation of Ir 4+ at potentials as low as 3.4 V versus Li + /Li 0 , as equivalently observed in the layered α-Li 2 IrO 3 polymorph. Theoretical calculations elucidate the electrochemical similarities and differences of the 3D versus 2D polymorphs in terms of structural, electronic and mechanical descriptors. Our findings free the structural dimensionality constraint and broaden the possibilities in designing high-energy-density electrodes for the next generation of Li-ion batteries.

New derivatives of 3,4-dihydroisoquinoline-3-carboxylic acid with free-radical scavenging, D-amino acid oxidase, acetylcholinesterase and butyrylcholinesterase inhibitory activity.

PubMed

Solecka, Jolanta; Guśpiel, Adam; Postek, Magdalena; Ziemska, Joanna; Kawęcki, Robert; Lęczycka, Katarzyna; Osior, Agnieszka; Pietrzak, Bartłomiej; Pypowski, Krzysztof; Wyrzykowska, Agata

2014-09-30

A series of 3,4-dihydroisoquinoline-3-carboxylic acid derivatives were synthesised and tested for their free-radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS·+), superoxide anion radical (O2·-) and nitric oxide radical (·NO) assays. We also studied d-amino acid oxidase (DAAO), acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity. Almost each of newly synthesised compounds exhibited radical scavenging capabilities. Moreover, several compounds showed moderate inhibitory activities against DAAO, AChE and BuChE. Compounds with significant free-radical scavenging activity may be potential candidates for therapeutics used in oxidative-stress-related diseases.

Antioxidant activities of crude phlorotannins from Sargassum hemiphyllum.

PubMed

Zhao, Zhi-Li; Yang, Xiao-Qing; Gong, Zhong-Qing; Pan, Ming-Zhu; Han, Ya-Li; Liu, Yi

2016-06-01

Brown algae are well known as a source of biologically active compounds, especially those having antioxidant activities, such as phlorotannins. In this study we examined the antioxidant activities of crude phlorotannins extracts (CPEs) obtained from Sargassum hemiphyllum (SH) and fractionated according to the molecular weights. When CPEs were administrated at a dose of 30 mg/kg to Kunming mice pre-treated with carbon tetrachloride (CCl4), the levels of oxidative stress indicators in the liver, kidney and brain were significantly reduced in vivo. All the components of various molecular weight fractions of CPEs exhibited greater scavenging capacities in clearing hydroxyl free radical and superoxide anion than the positive controls gallic acid, vitamin C and vitamin E. Particularly, the components greater than 30 kD obtained from ethyl acetate phase showed the highest antioxidant capacities. These results indicated that SH is a potential source for extracting phlorotannins, the algal antioxidant compounds.

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

PubMed

Beyer, W F; Fridovich, I

1991-02-15

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

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

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

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

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

Anionic pH-Sensitive Lipoplexes.

PubMed

Mignet, Nathalie; Scherman, Daniel

2017-01-01

To provide long circulating nanoparticles able to carry a gene to tumors, we have designed anionic pegylated lipoplexes which are pH sensitive. Anionic pegylated lipoplexes have been prepared from the combined formulation of cationic lipoplexes and pegylated anionic liposomes. The neutralization of the particle surface charge as a function of the pH was monitored by light scattering in order to determine the ratio between anionic and cationic lipids that would give pH sensitive complexes. This ratio has been optimized to form particles sensitive to pH change in the range 5.5-6.5. Compaction of DNA into these newly formed anionic complexes is checked by DNA accessibility to picogreen. The transfection efficiency and pH sensitive property of these formulations has been shown in vitro using bafilomycin, a vacuolar H + -ATPase inhibitor.

Anion-π Catalysis on Fullerenes.

PubMed

López-Andarias, Javier; Frontera, Antonio; Matile, Stefan

2017-09-27

Anion-π interactions on fullerenes are about as poorly explored as the use of fullerenes in catalysis. However, strong exchange-correlation contributions and the localized π holes on their surface promise unique selectivities. To elaborate on this promise, tertiary amines are attached nearby. Dependent on their positioning, the resulting stabilization of anionic transition states on fullerenes is shown to accelerate disfavored enolate addition and exo Diels-Alder reactions enantioselectively. The found selectivities are consistent with computational simulations, particularly concerning the discrimination of differently planarized and charge-delocalized enolate tautomers by anion-π interactions. Enolate-π interactions on fullerenes are much shorter than standard π-π interactions and anion-π interactions on planar surfaces, and alternative cation-π interactions are not observed. These findings open new perspectives with regard to anion-π interactions in general and the use of carbon allotropes in catalysis.

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

PubMed Central

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

2014-01-01

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

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.

PubMed

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.

Revealing mechanisms of selective, concentration-dependent potentials of 4-hydroxy-2-nonenal to induce apoptosis in cancer cells through inactivation of membrane-associated catalase.

PubMed

Bauer, Georg; Zarkovic, Neven

2015-04-01

Tumor cells generate extracellular superoxide anions and are protected against superoxide anion-mediated intercellular apoptosis-inducing signaling by the expression of membrane-associated catalase. 4-Hydroxy-2-nonenal (4-HNE), a versatile second messenger generated during lipid peroxidation, has been shown to induce apoptosis selectively in malignant cells. The findings described in this paper reveal the strong, concentration-dependent potential of 4-HNE to specifically inactivate extracellular catalase of tumor cells both indirectly and directly and to consequently trigger apoptosis in malignant cells through superoxide anion-mediated intercellular apoptosis-inducing signaling. Namely, 4-HNE caused apoptosis selectively in NOX1-expressing tumor cells through inactivation of their membrane-associated catalase, thus reactivating subsequent intercellular signaling through the NO/peroxynitrite and HOCl pathways, followed by the mitochondrial pathway of apoptosis. Concentrations of 4-HNE of 1.2 µM and higher directly inactivated membrane-associated catalase of tumor cells, whereas at lower concentrations, 4-HNE triggered a complex amplificatory pathway based on initial singlet oxygen formation through H2O2 and peroxynitrite interaction. Singlet-oxygen-dependent activation of the FAS receptor and caspase-8 increased superoxide anion generation by NOX1 and amplification of singlet oxygen generation, which allowed singlet-oxygen-dependent inactivation of catalase. 4-HNE and singlet oxygen cooperate in complex autoamplificatory loops during this process. The finding of these novel anticancer pathways may be useful for understanding the role of 4-HNE in the control of malignant cells and for the optimization of ROS-dependent therapeutic approaches including antioxidant treatments. Copyright © 2015 Elsevier Inc. All rights reserved.

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

PubMed

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

1999-09-15

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

[Study on effect of jinshui liujun jian oral liquid on serum superoxide dismutase activity and malonyldialdehyde content in mice with chronic bronchitis].

PubMed

Zhao, C Y; Shen, Y S; Meng, H

2001-11-01

To study the effect of Jinshui Liujun Jian Oral Liquid (JLJOL) on serum superoxide dismutase (SOD) activity and malonyldialdehyde (MDA) content in mice with chronic bronchitis. JLJOL was given to the chronic bronchitis mice model (induced by smoking) through gastrogavage, and then SOD activity and MDA content were tested. SOD activity in model mice after JLJOL treatment was 0.67 +/- 0.15 NU/L, which was significantly higher than that in the untreated model (0.39 +/- 0.13 NU/L, P < 0.01). But the MDA content in treated mice was significantly lower than that in untreated one (9.26 +/- 2.90 nmol/L vs 16.07 +/- 5.62 nmol/L, P < 0.01). JLJOL could scavenge the injury of free radical on organism.

Synergistic Anion-(π) n-π Catalysis on π-Stacked Foldamers.

PubMed

Bornhof, Anna-Bea; Bauzá, Antonio; Aster, Alexander; Pupier, Marion; Frontera, Antonio; Vauthey, Eric; Sakai, Naomi; Matile, Stefan

2018-04-11

In this report, we demonstrate that synergistic effects between π-π stacking and anion-π interactions in π-stacked foldamers provide access to unprecedented catalytic activity. To elaborate on anion-(π) n -π catalysis, we have designed, synthesized and evaluated a series of novel covalent oligomers with up to four face-to-face stacked naphthalenediimides (NDIs). NMR analysis including DOSY confirms folding into π stacks, cyclic voltammetry, steady-state and transient absorption spectroscopy the electronic communication within the π stacks. Catalytic activity, assessed by chemoselective catalysis of the intrinsically disfavored but biologically relevant addition reaction of malonate half thioesters to enolate acceptors, increases linearly with the length of the stacks to reach values that are otherwise beyond reach. This linear increase violates the sublinear power laws of oligomer chemistry. The comparison of catalytic activity with ratiometric changes in absorption and decreasing energy of the LUMO thus results in superlinearity, that is synergistic amplification of anion-π catalysis by remote control over the entire stack. In computational models, increasing length of the π-stacked foldamers correlates sublinearly with changes in surface potentials, chloride binding energies, and the distances between chloride and π surface and within the π stack. Computational evidence is presented that the selective acceleration of disfavored but relevant enolate chemistry by anion-π catalysis indeed originates from the discrimination of planar and bent tautomers with delocalized and localized charges, respectively, on π-acidic surfaces. Computed binding energies of keto and enol intermediates of the addition reaction as well as their difference increase with increasing length of the π stack and thus reflect experimental trends correctly. These results demonstrate that anion-(π) n -π interactions exist and matter, ready for use as a unique new tool in catalysis

Activation of Cu,Zn-superoxide dismutase in the absence of oxygen and the copper chaperone CCS.

PubMed

Leitch, Jeffry M; Jensen, Laran T; Bouldin, Samantha D; Outten, Caryn E; Hart, P John; Culotta, Valeria C

2009-08-14

Eukaryotic Cu,Zn-superoxide dismutases (SOD1s) are generally thought to acquire the essential copper cofactor and intramolecular disulfide bond through the action of the CCS copper chaperone. However, several metazoan SOD1s have been shown to acquire activity in vivo in the absence of CCS, and the Cu,Zn-SOD from Caenorhabditis elegans has evolved complete independence from CCS. To investigate SOD1 activation in the absence of CCS, we compared and contrasted the CCS-independent activation of C. elegans and human SOD1 to the strict CCS-dependent activation of Saccharomyces cerevisiae SOD1. Using a yeast expression system, both pathways were seen to acquire copper derived from cell surface transporters and compete for the same intracellular pool of copper. Like CCS, CCS-independent activation occurs rapidly with a preexisting pool of apo-SOD1 without the need for new protein synthesis. The two pathways, however, strongly diverge when assayed for the SOD1 disulfide. SOD1 molecules that are activated without CCS exhibit disulfide oxidation in vivo without oxygen and under copper-depleted conditions. The strict requirement for copper, oxygen, and CCS in disulfide bond oxidation appears exclusive to yeast SOD1, and we find that a unique proline at position 144 in yeast SOD1 is responsible for this disulfide effect. CCS-dependent and -independent pathways also exhibit differential requirements for molecular oxygen. CCS activation of SOD1 requires oxygen, whereas the CCS-independent pathway is able to activate SOD1s even under anaerobic conditions. In this manner, Cu,Zn-SOD from metazoans may retain activity over a wide range of physiological oxygen tensions.

Paroxysmal atrial fibrillation: dynamics of the main antioxidant enzymes--superoxide dismutase and catalase.

PubMed

Negreva, Mariya N; Penev, Atanas P; Georgiev, Svetoslav Zh; Aleksandrova, Albena A

2014-01-01

Researchers have a particularly strong interest in the mechanisms implicated in the clinical manifestation of atrial fibrillation. To examine dynamically the activity of the antioxidant enzymes, superoxide dismutase and catalase in patients with paroxysmal atrial fibrillation (duration < 48 hours). The studied parameters were examined in the erythrocytes of 51 patients (59.84 +/- 1.60, 26 men) immediately after their hospitalization, at 24 hours and 28 days after restoration of sinus rhythm. 52 controls (59.50 +/- 1.46, 26 men) were also included, none of which had a history of arrhythmia. Propafenone was used to manage the rhythm abnormality. The enzyme activity was determined by a spectrophotometric method. The average duration of atrial fibrillation episodes until the time of hospitalization was 8.14 hours (from 2 to 24 hours). During patient hospitalization the activity of superoxide dismutase and catalase was considerably higher compared to that of the controls (8.46 +/- 0.26 vs 5.81 +/- 0.14 U/mg Hb; 7.36 +/- 0.25 vs 4.76 +/- 0.12 E240/min/mg Hb; P < 0.001). This difference was maintained 24 hours after the rhythm regularization (7.19 +/- 0.25 vs 5.81 +/- 0.14 U/mg Hb, p < 0.001; 5.30 +/- 0.21 vs 4.76 +/- 0.12 E240/min/mg Hb, p < 0.05). Twenty-eight days after the restoration of sinus rhythm, the activity of catalase remained increased (5.11 +/- 0.08 vs 4.76 +/- 0.12 E240/min/mg Hb, p < 0.05). The paroxysmal atrial fibrillation in our study was characterized with significantly increased activity of superoxide dismutase and catalase even in the early hours of clinical manifestation of the disorder, which then slowly decreased with the restoration of sinus rhythm. Therefore, we can conclude that changes in oxidative status are closely related to the disease and are probably a part of the intimate mechanisms related to its initiation and clinical course.

Contribution of attendant anions on cadmium toxicity to soil enzymes.

PubMed

Tian, Haixia; Kong, Long; Megharaj, Mallavarapu; He, Wenxiang

2017-11-01

Sorption and desorption are critical processes to control the mobility and biotoxicity of cadmium (Cd) in soils. It is known that attendant anion species of heavy metals could affect metal adsorption on soils and might further alter their biotoxicity. However, for Cd, the influence of attendant anions on its sorption in soils and subsequent toxicity on soil enzymes are still unknown. In this work, four Cd compounds with different salt anions (SO 4 2- , NO 3 - , Cl - , and Ac - ) were selected to investigate their impact of on the sorption, soil dehydrogenase activity (DHA) and alkaline phosphatase activity (ALP). Thus, a series of simulated Cd pollution batch experiments including measuring adsorption-desorption behavior of Cd on soils and soil enzyme activities were carried out. Results showed that CdSO 4 exhibited highest sorption capacity among the tested soils except in Hunan soil. The Cd sorption with NO 3 - displayed a similar behavior with Cl - on all tested soils. Compared with soil properties, all four kinds of anions on Cd sorption played a more significant role affecting Cd ecological toxicity to soil DHA and ALP. Cd in acetate or nitrate form appears more sensitive towards DHA than sulphate and chloride, while the later pair is more toxic towards ALP than the former. These results have important implications for evaluation of Cd contamination using soil enzyme as bioindicator. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antioxidant and anti-inflammatory activities of extracts from Cassia alata, Eleusine indica, Eremomastax speciosa, Carica papaya and Polyscias fulva medicinal plants collected in Cameroon.

PubMed

Sagnia, Bertrand; Fedeli, Donatella; Casetti, Rita; Montesano, Carla; Falcioni, Giancarlo; Colizzi, Vittorio

2014-01-01

The vast majority of the population around the world has always used medicinal plants as first source of health care to fight infectious and non infectious diseases. Most of these medicinal plants may have scientific evidence to be considered in general practice. The aim of this work was to investigate the antioxidant capacities and anti-inflammatory activities of ethanol extracts of leaves of Cassia alata, Eleusine indica, Carica papaya, Eremomastax speciosa and the stem bark of Polyscias fulva, collected in Cameroon. Chemiluminescence was used to analyze the antioxidant activities of plant extracts against hydrogen peroxide or superoxide anion. Comet assays were used to analyze the protection against antioxidant-induced DNA damage induced in white blood cells after treating with hydrogen peroxide. Flow cytometry was used to measure γδ T cells proliferation and anti-inflammatory activity of γδ T cells and of immature dendritic cells (imDC) in the presence of different concentrations of plant extracts. Ethanol extracts showed strong antioxidant properties against both hydrogen peroxide and superoxide anion. Cassia alata showed the highest antioxidant activity. The effect of plant extracts on γδ T cells and imDC was evidenced by the dose dependent reduction in TNF-α production in the presence of Cassia alata, Carica papaya, Eremomastax speciosa Eleusine indica, and Polyscias fulva. γδ T cells proliferation was affected to the greatest extent by Polyscias fulva. These results clearly show the antioxidant capacity and anti-inflammatory activities of plant extracts collected in Cameroon. These properties of leaves and stem bark extracts may contribute to the value for these plants in traditional medicine and in general medical practice.

Antioxidant and Anti-Inflammatory Activities of Extracts from Cassia alata, Eleusine indica, Eremomastax speciosa, Carica papaya and Polyscias fulva Medicinal Plants Collected in Cameroon

PubMed Central

Sagnia, Bertrand; Fedeli, Donatella; Casetti, Rita; Montesano, Carla; Falcioni, Giancarlo; Colizzi, Vittorio

2014-01-01

Background The vast majority of the population around the world has always used medicinal plants as first source of health care to fight infectious and non infectious diseases. Most of these medicinal plants may have scientific evidence to be considered in general practice. Objective The aim of this work was to investigate the antioxidant capacities and anti-inflammatory activities of ethanol extracts of leaves of Cassia alata, Eleusine indica, Carica papaya, Eremomastax speciosa and the stem bark of Polyscias fulva, collected in Cameroon. Methods Chemiluminescence was used to analyze the antioxidant activities of plant extracts against hydrogen peroxide or superoxide anion. Comet assays were used to analyze the protection against antioxidant-induced DNA damage induced in white blood cells after treating with hydrogen peroxide. Flow cytometry was used to measure γδ T cells proliferation and anti-inflammatory activity of γδ T cells and of immature dendritic cells (imDC) in the presence of different concentrations of plant extracts. Results Ethanol extracts showed strong antioxidant properties against both hydrogen peroxide and superoxide anion. Cassia alata showed the highest antioxidant activity. The effect of plant extracts on γδ T cells and imDC was evidenced by the dose dependent reduction in TNF-α production in the presence of Cassia alata, Carica papaya, Eremomastax speciosa Eleusine indica, and Polyscias fulva. γδ T cells proliferation was affected to the greatest extent by Polyscias fulva. Conclusion These results clearly show the antioxidant capacity and anti-inflammatory activities of plant extracts collected in Cameroon. These properties of leaves and stem bark extracts may contribute to the value for these plants in traditional medicine and in general medical practice. PMID:25090613

Anion-activated, thermoreversible gelation system for the capture, release, and visual monitoring of CO2

NASA Astrophysics Data System (ADS)

Zhang, Xin; Lee, Songyi; Liu, Yifan; Lee, Minji; Yin, Jun; Sessler, Jonathan L.; Yoon, Juyoung

2014-04-01

Carbon dioxide (CO2) is an important green house gas. This is providing an incentive to develop new strategies to detect and capture CO2. Achieving both functions within a single molecular system represents an unmet challenge in terms of molecular design and could translate into enhanced ease of use. Here, we report an anion-activated chemosensor system, NAP-chol 1, that permits dissolved CO2 to be detected in organic media via simple color changes or through ratiometric differences in fluorescence intensity. NAP-chol 1 also acts as a super gelator for DMSO. The resulting gel is transformed into a homogeneous solution upon exposure to fluoride anions. Bubbling with CO2 regenerates the gel. Subsequent flushing with N2 or heating serves to release the CO2 and reform the sol form. This series of transformations is reversible and can be followed by easy-to-discern color changes. Thus, NAP-chol 1 allows for the capture and release of CO2 gas while acting as a three mode sensing system. In particular, it permits CO2 to be detected through reversible sol-gel transitions, simple changes in color, or ratiometric monitoring of the differences in the fluorescence features.

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

PubMed Central

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

2013-01-01

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

Hybrid capacitive deionization with anion-exchange membranes for lithium extraction

NASA Astrophysics Data System (ADS)

Siekierka, Anna; Bryjak, Marek

2017-11-01

Lithium is considered to be a critical material for various industrial fields. We present our studies on extraction lithium from diluted aqueous solution by novel hybrid system based on a membrane capacitive deionization and batteries desalination. Hybrid CDI is comprised by a lithium selective adsorbent, activated carbon electrode and anion-exchange membranes. Here, we demonstrated implication of various type of anion-exchange membranes and influence their properties on effective capacity and energy requirements in charge/discharge steps. We described a configuration with anion-exchange membrane characterized by adsorption capacity of 35 mg/g of Li+ with 0.08Wh/g and removal efficiency of 60 % of lithium ions, using novel selective desalination technique.

Antimicrobial Activity of ε-Poly-l-lysine after Forming a Water-Insoluble Complex with an Anionic Surfactant.

PubMed

Ushimaru, Kazunori; Hamano, Yoshimitsu; Katano, Hajime

2017-04-10

ε-Poly-l-lysine (ε-PL) is one of the few homopoly(amino-acid)s occurring in nature. ε-PL, which possesses multiple amino groups, is highly soluble in water, where it forms the antimicrobial polycationic chain (PL n+ ). Although the high water-solubility is advantageous for the use of ε-PL as a food preservative, it has limited the applicability of ε-PL as a biopolymer plastic. Here, we report on the preparation and availability of a water-insoluble complex formed with PL n+ and an anionic surfactant, bis(2-ethylhexyl) sulfosuccinate (BEHS - , is also commercialized as AOT) anion. The PL n+ /BEHS - -complex, which is soluble in organic solvents, was successfully used as a coating material for a cellulose acetate membrane to create a water-resistant antimicrobial membrane. In addition, the thermoplastic PL n+ /BEHS - -complex was able to be uniformly mixed with polypropylene by heating, resulting in materials exhibiting antimicrobial activities.

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

PubMed

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

2008-12-01

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

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

PubMed

Horspool, Alexander M; Chang, Howard C

2018-05-19

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

Anion Binding and Transport by Prodigiosin and Its Analogs

NASA Astrophysics Data System (ADS)

Davis, Jeffery T.

The red-colored prodiginines, exemplified by prodigiosin 1, are secondary metabolites produced by a number of microorganisms, including the bacterium Serratia marcescens. These tripyrrole natural products and their synthetic analogs have received renewed attention over the past deacade, primarily because of their promising immunosuppressive and anticancer activities. One of the hallmarks of prodiginin chemistry is the ability of the monoprotonated ligand to bind anions, including the essential chloride and bicarbonate ions. The resulting lipophilic ion pair is then able to diffuse across the hydrophobic barrier presented by phospholipid bilayers. Thus, prodiginines have been found to be potent transmembrane anion transporters and HCl cotransporters. In this chapter, the author reviews what is known about the solid-state structure of prodiginins and their anion complexes, the solution conformation of prodiginines, and the biochemcal evidence for the ability to bind anions and to transport HCl across cell membranes. Recent progress in making synthetic models of prodiginines and recent results on the ability of prodigiosin to transport HCO 3 - across lipid membranes are discussed.

Aza-Bambusurils En Route to Anion Transporters.

PubMed

Singh, Mandeep; Solel, Ephrath; Keinan, Ehud; Reany, Ofer

2016-06-20

Previous calculations of anion binding with various bambusuril analogs predicted that the replacement of oxygen by nitrogen atoms to produce semiaza-bambus[6]urils would award these new cavitands with multiple anion binding properties. This study validates the hypothesis by efficient synthesis, crystallography, thermogravimetric analysis and calorimetry. These unique host molecules are easily accessible from the corresponding semithio-bambusurils in a one-pot reaction, which converts a single anion receptor into a potential anion channel. Solid-state structures exhibit simultaneous accommodation of three anions, linearly positioned within the cavity along the main symmetry axis. The ability to hold anions at a short distance of about 4 Å is reminiscent of natural chloride channels in E. coli, which exhibit similar distances between their adjacent anion binding sites. The calculated transition-state energy for double-anion movement through the channel suggests that although these host-guest complexes are thermodynamically stable they enjoy high kinetic flexibility to render them efficient anion channels. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vinpocetine Reduces Carrageenan-Induced Inflammatory Hyperalgesia in Mice by Inhibiting Oxidative Stress, Cytokine Production and NF-κB Activation in the Paw and Spinal Cord

PubMed Central

Ruiz-Miyazawa, Kenji W.; Zarpelon, Ana C.; Pinho-Ribeiro, Felipe A.; Pavão-de-Souza, Gabriela F.; Casagrande, Rubia; Verri, Waldiceu A.

2015-01-01

Vinpocetine is a safe nootropic agent used for neurological and cerebrovascular diseases. The anti-inflammatory activity of vinpocetine has been shown in cell based assays and animal models, leading to suggestions as to its utility in analgesia. However, the mechanisms regarding its efficacy in inflammatory pain treatment are still not completely understood. Herein, the analgesic effect of vinpocetine and its anti-inflammatory and antioxidant mechanisms were addressed in murine inflammatory pain models. Firstly, we investigated the protective effects of vinpocetine in overt pain-like behavior induced by acetic acid, phenyl-p-benzoquinone (PBQ) and formalin. The intraplantar injection of carrageenan was then used to induce inflammatory hyperalgesia. Mechanical and thermal hyperalgesia were evaluated using the electronic von Frey and the hot plate tests, respectively, with neutrophil recruitment to the paw assessed by a myeloperoxidase activity assay. A number of factors were assessed, both peripherally and in the spinal cord, including: antioxidant capacity, reduced glutathione (GSH) levels, superoxide anion, tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) levels, as well as nuclear factor kappa B (NF-κB) activation. Vinpocetine inhibited the overt pain-like behavior induced by acetic acid, PBQ and formalin (at both phases), as well as the carrageenan-induced mechanical and thermal hyperalgesia and associated neutrophil recruitment. Both peripherally and in the spinal cord, vinpocetine also inhibited: antioxidant capacity and GSH depletion; increased superoxide anion; IL-1β and TNF-α levels; and NF-κB activation. As such, vinpocetine significantly reduces inflammatory pain by targeting oxidative stress, cytokine production and NF-κB activation at both peripheral and spinal cord levels. PMID:25822523

Vinpocetine reduces carrageenan-induced inflammatory hyperalgesia in mice by inhibiting oxidative stress, cytokine production and NF-κB activation in the paw and spinal cord.

PubMed

Ruiz-Miyazawa, Kenji W; Zarpelon, Ana C; Pinho-Ribeiro, Felipe A; Pavão-de-Souza, Gabriela F; Casagrande, Rubia; Verri, Waldiceu A

2015-01-01

Vinpocetine is a safe nootropic agent used for neurological and cerebrovascular diseases. The anti-inflammatory activity of vinpocetine has been shown in cell based assays and animal models, leading to suggestions as to its utility in analgesia. However, the mechanisms regarding its efficacy in inflammatory pain treatment are still not completely understood. Herein, the analgesic effect of vinpocetine and its anti-inflammatory and antioxidant mechanisms were addressed in murine inflammatory pain models. Firstly, we investigated the protective effects of vinpocetine in overt pain-like behavior induced by acetic acid, phenyl-p-benzoquinone (PBQ) and formalin. The intraplantar injection of carrageenan was then used to induce inflammatory hyperalgesia. Mechanical and thermal hyperalgesia were evaluated using the electronic von Frey and the hot plate tests, respectively, with neutrophil recruitment to the paw assessed by a myeloperoxidase activity assay. A number of factors were assessed, both peripherally and in the spinal cord, including: antioxidant capacity, reduced glutathione (GSH) levels, superoxide anion, tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) levels, as well as nuclear factor kappa B (NF-κB) activation. Vinpocetine inhibited the overt pain-like behavior induced by acetic acid, PBQ and formalin (at both phases), as well as the carrageenan-induced mechanical and thermal hyperalgesia and associated neutrophil recruitment. Both peripherally and in the spinal cord, vinpocetine also inhibited: antioxidant capacity and GSH depletion; increased superoxide anion; IL-1β and TNF-α levels; and NF-κB activation. As such, vinpocetine significantly reduces inflammatory pain by targeting oxidative stress, cytokine production and NF-κB activation at both peripheral and spinal cord levels.

Erythropoietin activates SIRT1 to protect human cardiomyocytes against doxorubicin-induced mitochondrial dysfunction and toxicity.

PubMed

Cui, Lan; Guo, Jiabin; Zhang, Qiang; Yin, Jian; Li, Jin; Zhou, Wei; Zhang, Tingfen; Yuan, Haitao; Zhao, Jun; Zhang, Li; Carmichael, Paul L; Peng, Shuangqing

2017-06-05

The hormone erythropoietin (EPO) has been demonstrated to protect against chemotherapy drug doxorubicin (DOX)-induced cardiotoxicity, but the underlying mechanism remains obscure. We hypothesized that silent mating type information regulation 2 homolog 1 (SIRT1), an NAD + -dependent protein deacetylase that activates peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α), plays a crucial role in regulating mitochondrial function and mediating the beneficial effect of EPO. Our study in human cardiomyocyte AC16 cells showed that DOX-induced cytotoxicity and mitochondrial dysfunction, as manifested by decreased mitochondrial DNA (mtDNA) copy number, mitochondrial membrane potential, and increased mitochondrial superoxide accumulation, can be mitigated by EPO pretreatment. EPO was found to upregulate SIRT1 activity and protein expression to reverse DOX-induced acetylation of PGC-1α and suppression of a suite of PGC-1α-activated genes involved in mitochondrial function and biogenesis, such as nuclear respiratory factor-1 (NRF1), mitochondrial transcription factor A (TFAM), citrate synthase (CS), superoxide dismutase 2 (SOD2), cytochrome c oxidase IV (COXIV), and voltage-dependent anion channel (VDAC). Silencing of SIRT1 via small RNA interference sensitized AC16 cells to DOX-induced cytotoxicity and reduction in mtDNA copy number. Although with SIRT1 silenced, EPO could reverse to some extent DOX-induced mitochondrial superoxide accumulation, loss of mitochondrial membrane potential and ATP depletion, it failed to normalize protein expression of PGC-1α and its downstream genes. Taken together, our results indicated that EPO may activate SIRT1 to enhance mitochondrial function and protect against DOX-induced cardiotoxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Chloride Anions on the Synthesis and Enhanced Catalytic Activity of Silver Nanocoral Electrodes for CO 2 Electroreduction

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

Hsieh, Yu-Chi; Senanayake, Sanjaya D.; Zhang, Yu

2015-09-04

Metallic silver (Ag) is known as an efficient electrocatalyst for the conversion of carbon dioxide (CO 2) to carbon monoxide (CO) in aqueous or nonaqueous electrolytes. However, polycrystalline silver electrocatalysts require significant overpotentials in order to achieve high selectivity toward CO 2 reduction, as compared to the side reaction of hydrogen evolution. Here we report a high-surface-area Ag nanocoral catalyst, fabricated by an oxidation–reduction method in the presence of chloride anions in an aqueous medium, for the electro-reduction of CO 2 to CO with a current efficiency of 95% at the low overpotential of 0.37 V and the current densitymore » of 2 mA cm –2. A lower limit of TOF of 0.4 s –1 and TON > 8.8 × 10 4 (over 72 h) was estimated for the Ag nanocoral catalyst at an overpotential of 0.49 V. The Ag nanocoral catalyst demonstrated a 32-fold enhancement in surface-area-normalized activity, at an overpotential of 0.49 V, as compared to Ag foil. We found that, in addition to the effect on nanomorphology, the adsorbed chloride anions play a critical role in the observed enhanced activity and selectivity of the Ag nanocoral electrocatalyst toward CO 2 reduction. Synchrotron X-ray photoelectron spectroscopy (XPS) studies along with a series of control experiments suggest that the chloride anions, remaining adsorbed on the catalyst surface under electrocatalytic conditions, can effectively inhibit the side reaction of hydrogen evolution and enhance the catalytic performance for CO 2 reduction.« less

Bioavailability of the ferulic acid-derived phenolic compounds of a rice bran enzymatic extract and their activity against superoxide production.

PubMed

Perez-Ternero, Cristina; Macià, Alba; de Sotomayor, Maria Alvarez; Parrado, Juan; Motilva, Maria-Jose; Herrera, Maria-Dolores

2017-06-21

Rice bran is an exceptional source of such antioxidant molecules as γ-oryzanol and ferulic acid, but their bioavailability and metabolism within this matrix remain unknown. The aims of this work were to describe the oral bioavailability and metabolic pathways of the ferulic acid-derived phenolic compounds contained in a rice bran enzymatic extract (RBEE), and to determine its effect on NADPH oxidase activity. Wistar rats were administered with RBEE and sacrificed at different times over a period of 24 h to obtain plasma. An additional group was used for collection of urine and faeces over a period of 48 h. The phenolic metabolites were determined by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS), and plasma pharmacokinetic parameters were calculated. In parallel, aortic rings were incubated in the plasma of rats sacrificed 30 min after RBEE gavage, or in the presence of RBEE, ferulic acid or γ-oryzanol. Endothelin-1-induced superoxide production was recorded by lucigenin-enhanced luminescence. Twenty-five ferulic acid metabolites showing biphasic behaviour were found in the plasma, most of which were found in the urine as well, while in the faeces, colonic metabolism led to simpler phenolic compounds. Superoxide production was abrogated by phenolic compound-enriched plasma and by RBEE and ferulic acid, thus showing the biological potential of RBEE as a nutraceutical ingredient.

Electron localization of anions probed by nitrile vibrations

DOE PAGES

Mani, Tomoyasu; Grills, David C.; Newton, Marshall D.; ...

2015-08-02

Localization and delocalization of electrons is a key concept in chemistry, and is one of the important factors determining the efficiency of electron transport through organic conjugated molecules, which have potential to act as “molecular wires”. This, in turn, substantially influences the efficiencies of organic solar cells and other molecular electronic devices. It is also necessary to understand the electronic energy landscape and the dynamics of electrons through molecular chain that govern their transport capabilities in one-dimensional conjugated chains so that we can better define the design principles of conjugated molecules for their applications. We show that nitrile ν(C≡N) vibrationsmore » respond to the degree of electron localization in nitrile-substituted organic anions by utilizing time-resolved infrared (TRIR) detection combined with pulse radiolysis. Measurements of a series of aryl nitrile anions allow us to construct a semi-empirical calibration curve between the changes in the ν(C≡N) IR shifts and the changes in the electronic charges from the neutral to the anion states in the nitriles; more electron localization in the nitrile anion results in larger IR shifts. Furthermore, the IR linewidth in anions can report a structural change accompanying changes in the electronic density distribution. Probing the shift of the nitrile ν(C≡N) IR vibrational bands enables us to determine how the electron is localized in anions of nitrile-functionalized oligofluorenes, considered as organic mixed-valence compounds. We estimate the diabatic electron transfer distance, electronic coupling strengths, and energy barriers in these organic mixed-valence compounds. The analysis reveals a dynamic picture, showing that the electron is moving back and forth within the oligomers with a small activation energy of ≤ k BT, likely controlled by the movement of dihedral angles between monomer units. Thus, implications for the electron transport capability

The activity of organic anion transporter-3: Role of dexamethasone.

PubMed

Wang, Haoxun; Liu, Chenchang; You, Guofeng

2018-02-01

Human organic anion transporter-3 (hOAT3) is richly expressed in the kidney, where it plays critical roles in the secretion, from the blood to urine, of clinically important drugs, such as anti-viral therapeutics, anti-cancer drugs, antibiotics, antihypertensives, and anti-inflammatories. In the current study, we examined the role of dexamethasone in hOAT3 transport activity in the kidney HEK293 cells. Cis-inhibition study showed that dexamethasone exhibited a concentration-dependent inhibition of hOAT3-mediated uptake of estrone sulfate, a prototypical substrate for the transporter, with IC 50 value of 49.91 μM. Dixon plot analysis revealed that inhibition by dexamethasone was competitive with a Ki = 47.08 μM. In contrast to the cis-inhibition effect of dexamethasone, prolonged incubation (6 h) of hOAT3-expressing cells with dexamethasone resulted in an upregulation of hOAT3 expression and transport activity, kinetically revealed as an increase in the maximum transport velocity V max without meaningful alteration in substrate-binding affinity K m . Such upregulation was abrogated by GSK650394, a specific inhibitor for serum- and glucocorticoid-inducible kinases (sgk). Dexamethasone also enhanced sgk1 phosphorylation. Our study demonstrated that dexamethasone exhibits dual effects on hOAT3: it is a competitive inhibitor for hOAT3-mediated transport, and interestingly, when entering the cells, it stimulates hOAT3 expression and transport activity through sgk1. Copyright © 2018 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

Superoxide and Singlet Oxygen Produced within the Thylakoid Membranes Both Cause Photosystem I Photoinhibition.

PubMed

Takagi, Daisuke; Takumi, Shigeo; Hashiguchi, Masaki; Sejima, Takehiro; Miyake, Chikahiro

2016-07-01

Photosystem I (PSI) photoinhibition suppresses plant photosynthesis and growth. However, the mechanism underlying PSI photoinhibition has not been fully clarified. In this study, in order to investigate the mechanism of PSI photoinhibition in higher plants, we applied repetitive short-pulse (rSP) illumination, which causes PSI-specific photoinhibition in chloroplasts isolated from spinach leaves. We found that rSP treatment caused PSI photoinhibition, but not PSII photoinhibition in isolated chloroplasts in the presence of O2 However, chloroplastic superoxide dismutase and ascorbate peroxidase activities failed to protect PSI from its photoinhibition. Importantly, PSI photoinhibition was largely alleviated in the presence of methyl viologen, which stimulates the production of reactive oxygen species (ROS) at the stromal region by accepting electrons from PSI, even under the conditions where CuZn-superoxide dismutase and ascorbate peroxidase activities were inactivated by KCN. These results suggest that the ROS production site, but not the ROS production rate, is critical for PSI photoinhibition. Furthermore, we found that not only superoxide (O2 (-)) but also singlet oxygen ((1)O2) is involved in PSI photoinhibition induced by rSP treatment. From these results, we suggest that PSI photoinhibition is caused by both O2 (-) and (1)O2 produced within the thylakoid membranes when electron carriers in PSI become highly reduced. Here, we show, to our knowledge, new insight into the PSI photoinhibition in higher plants. © 2016 American Society of Plant Biologists. All Rights Reserved.

Discovery of Indeno[1,2-c]quinoline Derivatives as Potent Dual Antituberculosis and Anti-Inflammatory Agents.

PubMed

Tseng, Chih-Hua; Tung, Chun-Wei; Wu, Chen-Hsin; Tzeng, Cherng-Chyi; Chen, Yen-Hsu; Hwang, Tsong-Long; Chen, Yeh-Long

2017-06-16

A series of indeno[1,2- c ]quinoline derivatives were designed, synthesized and evaluated for their anti-tuberculosis (anti-TB) and anti-inflammatory activities. The minimum inhibitory concentration (MIC) of the newly synthesized compound was tested against Mycobacterium tuberculosis H 37 R V . Among the tested compounds, ( E )- N '-[6-(4-hydroxypiperidin-1-yl)-11 H -indeno[1,2- c ]quinolin-11-ylidene]isonicotino-hydrazide ( 12 ), exhibited significant activities against the growth of M. tuberculosis (MIC values of 0.96 μg/mL) with a potency approximately equal to that of isoniazid (INH), an anti-TB drug. Important structure features were analyzed by quantitative structure-activity relationship (QSAR) analysis to give better insights into the structure determinants for predicting the anti-TB activity. The anti-inflammatory activity was induced by superoxide anion generation and neutrophil elastase (NE) release using the formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLF)-activated human neutrophils method. Results indicated that compound 12 demonstrated a potent dual inhibitory effect on NE release and superoxide anion generation with IC 50 values of 1.76 and 1.72 μM, respectively. Our results indicated that compound 12 is a potential lead compound for the discovery of dual anti-TB and anti-inflammatory drug candidates. In addition, 6-[3-(hydroxymethyl)piperidin-1-yl]-9-methoxy-11 H -indeno[1,2- c ]quinolin-11-one ( 4g ) showed a potent dual inhibitory effect on NE release and superoxide anion generation with IC 50 values of 0.46 and 0.68 μM, respectively, and is a potential lead compound for the discovery of anti-inflammatory drug candidates.

Detection of Non-Photochemical Superoxide in Coastal and Open Ocean Seawater: Particulate Versus Dissolved Sources

NASA Astrophysics Data System (ADS)

Roe, K. L.; Rand, T.; Hansel, C. M.; Voelker, B. M.

2016-02-01

Superoxide radical (O2-) could have a significant effect on marine metal redox chemistry, but little data exists on its marine concentrations. In this study, we measured superoxide steady-state concentrations in both filtered and unfiltered samples collected near the California coast and at Station ALOHA. Particle-generated superoxide, defined as the difference between unfiltered and filtered concentrations, ranged from undetectable to 0.019 nM at Station ALOHA and from undetectable to 0.052 nM in samples from the southern California Current. We also show that a transient superoxide signal is generated during filtering, an artifact that may have affected previously reported concentrations of particle-generated superoxide in the ocean. High concentrations of superoxide (range) were measured in filtered samples from ALOHA station and the California Current, raising concerns about possible sources of background signals. Further study of background signals revealed that some superoxide production occurs even in artificial seawater and very aged filtered seawater samples, and that a small additional background signal is generated as the sample travels from the container to the flow cell where it is mixed with reagent for CL analysis. However, filtered seawater samples collected from the Scripps Pier had significantly higher superoxide production rates than those measured in artificial seawater, and production rates in unfiltered samples were no higher than those in filtered samples. Therefore, production by dissolved sources was the dominant non-photochemical source of superoxide in these samples. Production rates decreased in the presence of DTPA, suggesting involvement of metal ions in superoxide production. Laboratory experiments with natural organic matter (NOM) indicate that superoxide formation occurs during oxidation of reduced moieties of NOM by oxygen.

[Accelerated senescence of fresh-cut Chinese water chestnut tissues in relation to hydrogen peroxide accumulation].

PubMed

Peng, Li-Tao; Jiang, Yue-Ming; Yang, Shu-Zhen; Pan, Si-Yi

2005-10-01

Accelerated senescence of fresh-cut Chinese water chestnut (CWC) tissues in relation to active oxygen species (AOS) metabolism was investigated. Fresh-cut CWC (2 mm thick) and intact CWC were stored at 4 degrees C in trays wrapped with plastic films. Changes in superoxide anion production rate, activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) were monitored, while contents of hydrogen peroxide, ascorbic acid, MDA as well as electrolyte leakage were measured. Fresh-cutting of CWC induced activities of SOD, CAT and APX to a certain extent (Fig. 2B and Fig. 3), but simultaneously stimulated superoxide anion production markedly (Fig. 2A), enhanced hydrogen peroxide accumulation and accelerated loss in ascorbic acid (Figs. 4 and 5), which resulted in increased lipid peroxidation indicated by malondialdehyde (MDA) content and electrolyte leakage (Fig. 1). Statistics analysis indicated that there was a significantly positive correlation among hydrogen peroxide accumulation, MDA content and electrolyte leakage (Table 1). Histochemical detection with 3, 3'-diaminobenzidine further demonstrated that hydrogen peroxide accumulation increased in fresh-cut CWC during storage (Fig. 5). AOS production rate and activities of SOD, CAT and APX changed little while no obvious hydrogen peroxide accumulation was observed, in intact CWC during storage.

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

NASA Astrophysics Data System (ADS)

Lespade, Laure

2016-08-01

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

Models for the mechanism for activating copper-zinc superoxide dismutase in the absence of the CCS Cu chaperone in Arabidopsis.

PubMed

Huang, Chien-Hsun; Kuo, Wen-Yu; Jinn, Tsung-Luo

2012-03-01

Copper-zinc superoxide dismutase (CuZnSOD; CSD) is an important antioxidant enzyme for oxidative stress protection. To date, two activation pathways have been identified in many species. One requiring the CCS, Cu chaperone for SOD, to insert Cu and activate CSD (referred to as CCS-dependent pathway), and the other works independently of CCS (referred to as CCS-independent pathway). In our previous study, we suggest an unidentified factor will work with glutathione (GSH) for CSD activation in the absence of the CCS. Here, two models of the CCS-independent mechanism are proposed. The role of the unidentified factor may work as a scaffold protein, which provides a platform for the CSD protein and Cu-GSH to interact, or as a Cu carrier, which itself can bind Cu and interact with CSD proteins. We also suggest that the CSD protein conformation at C-terminal is important in providing a docking site for unidentified factor to access.

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

PubMed

Bauer, Georg

2017-02-01

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

Enterocyte protein tyrosine nitration in response to Eimeria infection in broilers

USDA-ARS?s Scientific Manuscript database

Activation of pathogen-sensing mechanisms in intestinal cells initiate the generation of pathway effectors that perturb normal nutritional enterocyte (ETC) functions. Among the conserved pathway mediator molecules generated are nitric oxide (NO) and superoxide anion (SOA) which are known to interac...

Synthesis of Novel Thiazole Based Carbaldehyde as Potential Sensor for Fluoride Anion and their Spectroscopic Properties.

PubMed

Tayade, Rajratna P; Sekar, Nagaiyan

2017-05-01

A novel thiazole based carbaldehyde bearing benzimidazole fluorophore as the receptor unit for F - anion was prepared by multi steps synthesis. Density functional theory was used to understand the structural and electronic properties the receptor. The anion sensing activities of receptor 4 were studied for various anions in acetonitrile solvent. The receptor showed fluorescence enhancement in the presence of fluoride anion due to intramolecular charge transfer (ICT) mechanism. No significant changes were observed upon addition of less basic anions such as OAc - , Cl - , Br - , I - , HSO 4 - . After the interaction of fluoride anion with the receptor 4 leads to an 88 nm red shift in emission maxima. [TBA]OH and 1 H NMR titration experiments indicated that deprotonation of N-H in the benzimidazole due to interaction with fluoride anions.

Early superoxide scavenging accelerates renal microvascular rarefaction and damage in the stenotic kidney.

PubMed

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

Early superoxide scavenging accelerates renal microvascular rarefaction and damage in the stenotic kidney

PubMed Central

Kelsen, Silvia; He, Xiaochen

2012-01-01

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

Nitric oxide and superoxide mediate diesel particle effects in cytokine-treated mice and murine lung epithelial cells — implications for susceptibility to traffic-related air pollution

PubMed Central

2012-01-01

Background Epidemiologic studies associate childhood exposure to traffic-related air pollution with increased respiratory infections and asthmatic and allergic symptoms. The strongest associations between traffic exposure and negative health impacts are observed in individuals with respiratory inflammation. We hypothesized that interactions between nitric oxide (NO), increased during lung inflammatory responses, and reactive oxygen species (ROS), increased as a consequence of traffic exposure ─ played a key role in the increased susceptibility of these at-risk populations to traffic emissions. Methods Diesel exhaust particles (DEP) were used as surrogates for traffic particles. Murine lung epithelial (LA-4) cells and BALB/c mice were treated with a cytokine mixture (cytomix: TNFα, IL-1β, and IFNγ) to induce a generic inflammatory state. Cells were exposed to saline or DEP (25 μg/cm2) and examined for differential effects on redox balance and cytotoxicity. Likewise, mice undergoing nose-only inhalation exposure to air or DEP (2 mg/m3 × 4 h/d × 2 d) were assessed for differential effects on lung inflammation, injury, antioxidant levels, and phagocyte ROS production. Results Cytomix treatment significantly increased LA-4 cell NO production though iNOS activation. Cytomix +  DEP-exposed cells incurred the greatest intracellular ROS production, with commensurate cytotoxicity, as these cells were unable to maintain redox balance. By contrast, saline + DEP-exposed cells were able to mount effective antioxidant responses. DEP effects were mediated by: (1) increased ROS including superoxide anion (O2˙-), related to increased xanthine dehydrogenase expression and reduced cytosolic superoxide dismutase activity; and (2) increased peroxynitrite generation related to interaction of O2˙- with cytokine-induced NO. Effects were partially reduced by superoxide dismutase (SOD) supplementation or by blocking iNOS induction. In mice, cytomix +  DEP

NADPH OXIDASE: STRUCTURE AND ACTIVATION MECHANISMS (REVIEW). NOTE I.

PubMed

Filip-Ciubotaru, Florina; Manciuc, Carmen; Stoleriu, Gabriela; Foia, Liliana

2016-01-01

NADPH oxidase (nicotinamide adenine dinucleotide phosphate-oxidase), with its generically termed NOX isoforms, is the major source of ROS (reactive oxigen species) in biological systems. ROS are small oxygen-derived molecules with an important role in various biological processes (physiological or pathological). If under physiological conditions some processes are beneficial and necessary for life, under pathophysiological conditions they are noxious, harmful. NADPH oxidases are present in phagocytes and in a wide variety of nonphagocytic cells. The enzyme generates superoxide by transferring electrons from NADPH inside the cell across the membrane and coupling them to molecular oxygen to produce superoxide anion, a reactive free-radical. Structurally, NADPH oxidase is a multicomponent enzyme which includes two integral membrane proteins, glycoprotein gp9 1 Phox and adaptor protein p22(phox), which together form the heterodimeric flavocytochrome b558 that constitutes the core of the enzyme. During the resting state, the multidomain regulatory subunits p40P(phox), p47(phox), p67(Phox) are located in the cytosol organized as a complex. The activation of phagocytic NADPH oxidase occurs through a complex series of protein interactions.

In vitro and in vivo antioxidant and antimutagenic activities of polyphenols extracted from hops (Humulus lupulus L.).

PubMed

Wang, Xuping; Yang, Lei; Yang, Xiaolan; Tian, Yanhua

2014-06-01

Hops (Humulus lupulus L.) contain 40-140 mg g(-1) polyphenols. The objective of this study was to determine the phenolic composition of a high-purity (total phenolic content = 887 mg g(-1) ) hop polyphenol extract (HPE) and evaluate its antioxidant activities in vivo and in vitro and its antimutagenic activity. The antioxidant activity of HPE was compared with the activity of green tea polyphenols. The phenolic compositions of HPE were more than 55% proanthocyanidins and more than 28% flavonoid glycosides. In vitro, HPE effectively scavenged α,α-diphenyl-β-picrylhydrazyl, hydroxyl and superoxide anion radicals, and inhibited DNA oxidative damage. In vivo, oral HPE at a polyphenol dose of 200-800 mg kg(-1) body weight significantly prevented a bromobenzene-induced decrease in liver superoxide dismutase and glutathione peroxidase activity, and decreased levels of liver thiobarbituric acid reactive substances in bromobenzene-treated mice. An oral dose of 20-80 mg kg(-1) body weight HPE significantly reduced the frequency of bone marrow micronuclei induced by cyclophosphamide. The antioxidant activities of hop polyphenols in vitro and in vivo were higher than green tea polyphenols at the same concentration. Hop polyphenols had the same or higher antioxidant activity than tea polyphenols. Hop polyphenols might be useful as natural antioxidants and antimutagens. © 2013 Society of Chemical Industry.

Tip-localized Ca2+ -permeable channels control pollen tube growth via kinase-dependent R- and S-type anion channel regulation.

PubMed

Gutermuth, Timo; Herbell, Sarah; Lassig, Roman; Brosché, Mikael; Romeis, Tina; Feijó, José Alberto; Hedrich, Rainer; Konrad, Kai Robert

2018-05-01

Pollen tubes (PTs) are characterized by having tip-focused cytosolic calcium ion (Ca 2+ ) concentration ([Ca 2+ ] cyt ) gradients, which are believed to control PT growth. However, the mechanisms by which the apical [Ca 2+ ] cyt orchestrates PT growth are not well understood. Here, we aimed to identify these mechanisms by combining reverse genetics, cell biology, electrophysiology, and live-cell Ca 2+ and anion imaging. We triggered Ca 2+ -channel activation by applying hyperpolarizing voltage pulses and observed that the evoked [Ca 2+ ] cyt increases were paralleled by high anion channel activity and a decrease in the cytosolic anion concentration at the PT tip. We confirmed a functional correlation between these patterns by showing that inhibition of Ca 2+ -permeable channels eliminated the [Ca 2+ ] cyt increase, resulting in the abrogation of anion channel activity via Ca 2+ -dependent protein kinases (CPKs). Functional characterization of CPK and anion-channel mutants revealed a CPK2/20/6-dependent activation of SLAH3 and ALMT12/13/14 anion channels. The impaired growth phenotypes of anion channel and CPK mutants support the physiological significance of a kinase- and Ca 2+ -dependent pathway to control PT growth via anion channel activation. Other than unveiling this functional link, our membrane hyperpolarization method allows for unprecedented manipulation of the [Ca 2+ ] cyt gradient or oscillations in the PT tips and opens an array of opportunities for channel screenings. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

Ion exchange polymers for anion separations

DOEpatents

Jarvinen, Gordon D.; Marsh, S. Fredric; Bartsch, Richard A.

1997-01-01

Anion exchange resins including at least two positively charged sites and a ell-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene.

Ion exchange polymers for anion separations

DOEpatents

Jarvinen, G.D.; Marsh, S.F.; Bartsch, R.A.

1997-09-23

Anion exchange resins including at least two positively charged sites and a well-defined spacing between the positive sites are provided together with a process of removing anions or anionic metal complexes from aqueous solutions by use of such resins. The resins can be substituted poly(vinylpyridine) and substituted polystyrene.