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Sample records for medium modulates oxidative

  1. Metabolic Modulation by Medium-Chain Triglycerides Reduces Oxidative Stress and Ameliorates CD36-Mediated Cardiac Remodeling in Spontaneously Hypertensive Rat in the Initial and Established Stages of Hypertrophy.

    Science.gov (United States)

    Saifudeen, Ismael; Subhadra, Lakshmi; Konnottil, Remani; Nair, R Renuka

    2017-03-01

    Left ventricular hypertrophy (LVH) is characterized by a decrease in oxidation of long-chain fatty acids, possibly mediated by reduced expression of the cell-surface protein cluster of differentiation 36 (CD36). Spontaneously hypertensive rats (SHRs) were therefore supplemented with medium-chain triglycerides (MCT), a substrate that bypasses CD36, based on the assumption that the metabolic modulation will ameliorate ventricular remodeling. The diet of 2-month-old and 6-month-old SHRs was supplemented with 5% MCT (Tricaprylin), for 4 months. Metabolic modulation was assessed by mRNA expression of peroxisome proliferator-activated receptor α and medium-chain acyl-CoA dehydrogenase. Blood pressure was measured noninvasively. LVH was assessed with the use of hypertrophy index, cardiomyocyte cross-sectional area, mRNA expression of B-type natriuretic peptide, cardiac fibrosis, and calcineurin-A levels. Oxidative stress indicators (cardiac malondialdehyde, protein carbonyl, and 3-nitrotyrosine levels), myocardial energy level (ATP, phosphocreatine), and lipid profile were determined. Supplementation of MCT stimulated fatty acid oxidation in animals of both age groups, reduced hypertrophy and oxidative stress along with the maintenance of energy level. Blood pressure, body weight, and lipid profile were unaffected by the treatment. The results indicate that modulation of myocardial fatty acid metabolism by MCT prevents progressive cardiac remodeling in SHRs, possibly by maintenance of energy level and decrease in oxidative stress. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Coal char oxidation kinetics in air medium

    Directory of Open Access Journals (Sweden)

    Korotkikh Alexander G.

    2017-01-01

    Full Text Available Study of oxidation kinetics for three types of coal char with different carbon content in air is presented. The coal char powders of anthracite, bituminous T-grade coal and 2B-grade lignite with particle size less than 80 μm were tested. The coal char oxidation was researched by isothermal method via simultaneous TG-DSC analyzer Netzsch STA 449 Jupiter F3 in the temperature range of 1000–1200 °C. Measurements were carried out at ambient pressure. Volumetric flow rate of oxidizing medium into analyser chamber was 250 ml/min. Flow consisted of air and argon with volumetric ratio 24/1. Carbon average rate of oxidation reaction at each temperature were defined based on experimental results. Kinetic constants (the frequency factor and activation energy were defined for Arrhenius equation modified with three submodels: volumetric model, shrinking core model and random pore model. The activation energy values for anthracite are 1,6-1,7 times higher than for chars of bituminous coal and lignite.

  3. Medium-Term Outcome of Sacral Nerve Modulation for Constipation

    DEFF Research Database (Denmark)

    Govaert, Bastiaan; Maeda, Yasuko; Alberga, Job

    2012-01-01

    BACKGROUND: Sacral nerve modulation has been reported as a minimally invasive and effective treatment for constipation refractory to conservative treatment. OBJECTIVE: This study aimed to evaluate the efficacy and sustainability of sacral nerve modulation for constipation in the medium term (up......: Patients were eligible if they had had symptoms of constipation persisting for at least 1 year, if conservative treatment (dietary modification, laxatives and biofeedback therapy) had failed, and if predefined excluded conditions were not present. INTERVENTION: The first phase of the treatment process...... constipation score. RESULTS: A total of 117 patients (13 men, 104 women) with a mean age of 45.6 (SD, 13.0) years underwent percutaneous nerve evaluation. Of these, 68 patients (58%) had successful percutaneous nerve evaluation and underwent implantation of a device. The mean Wexner score was 17.0 (SD, 3...

  4. Iron or iron oxide grains in the interstellar medium?

    International Nuclear Information System (INIS)

    Jones, A.P.

    1990-01-01

    Iron grains have often been proposed as a component of circumstellar and interstellar grains. It is apparent that 'cosmic abundance' circumstellar shells should condense iron-rich particles such as metallic iron, iron/nickel alloys and iron carbides. It is not, however, clear that these grains can survive in this state in the interstellar medium. In this paper the chemistry of iron particles in the diffuse interstellar medium is examined and it is concluded that these grains cannot survive as pristine metallic iron-rich entities. The reactivity of iron, and in particular its reaction with interstellar gas-phase oxygen and sulphur species, will result in the rapid degradation of the metal to an oxide, sulphide or even sulphate. The lack of metallic phases in the mineralogy of primitive interplanetary dust particles is consistent with the absence of metallic particles in the interstellar medium. (author)

  5. Modulation of the Casimir force by laser pulses: Influence of oxide films on the silicon surface

    Science.gov (United States)

    Klimchitskaya, G. L.; Bukina, M. N.; Churkin, Yu. V.; Yurova, V. A.

    2010-10-01

    The possibility of modulating the Casimir force that acts in an air medium between a gold sphere and a silicon plate irradiated by laser pulses has been studied. It has been demonstrated that the oxide film that is formed on the silicon surface in air hardly affects the possibility of modulating the Casimir force when the distances between interacting bodies are of the order of 100 nm. With an increase in the distance, the modulation depth decreases; however, this region is of less practical interest, because the Casimir forces become too weak.

  6. Kinetics of Oxidation of 3-Benzoylpropionic Acid by N-Chlorobenzamide in Aqueous Acetic Acid Medium

    Directory of Open Access Journals (Sweden)

    N. A. Mohamed Farook

    2011-01-01

    Full Text Available The kinetics of oxidation of 3-benzoylpropionic acid (KA by N-chlorobenzamide (NCB in aqueous acetic acid medium in the presence of perchloric acid have been investigated. The observed rate of oxidation is first order dependence each in [KA], [NCB] and [H+]. The main product of the oxidation is the corresponding carboxylic acid. The rate decreases with the addition of benzamide, one of the products of the reaction. Variation in ionic strength of the reaction medium has no significant effect on the rate of oxidation. But the rate of the reaction is enhanced by lowering the dielectric constant of the reaction medium. Hypochlorous acidium ion (H2O+Cl, has been postulated as the reactive oxidizing species. A mechanism consistent with observed results have been proposed and the related rate law deduced. The activation parameters have been computed with respect to slow step of the mechanism.

  7. Muscle force production with low and medium frequency burst modulated biphasic pulsed currents.

    Science.gov (United States)

    Bellew, James W; Sanders, Kyle; Schuman, Kristen; Barton, Matt

    2014-02-01

    Russian current, a medium frequency burst modulated alternating current (BMAC), is widely used for NMES, but has not been shown to elicit forces near voluntary maximum. In contrast, low frequency BMAC has been shown to produce greater force production than Russian and most recently, medium frequency burst modulated biphasic pulsed current (BMBPC) elicited greater force than Russian. Whether low frequency BMBPC yields greater force than medium frequency BMBPC is unknown. This study examined elicited forces using BMBPC with low and medium frequency carrier currents. A cross-over design where percent maximal isometric knee extensor forces (%MVIF) elicited using BMBPC with low or medium kilohertz carrier frequencies were compared in 23 subjects. Perceived discomfort was also assessed. Data were compared using paired samples t-tests. 98.4% of the MVIF was elicited with the low frequency BMBPC which was significantly greater (p current. Cohen's d effect size of 2.146 indicated a "huge effect". Perceived discomfort of the low frequency current was 5.7/10 and was significantly greater (p current (3.6/10). BMBPC with low frequency carrier current elicits forces approximating maximal volitional force. These findings offer new evidence with strong clinical implications when using NMES.

  8. Possible nitric oxide modulation in the protective effect of trazodone ...

    African Journals Online (AJOL)

    Conclusion: Results of present study suggest that NO modulation is involved in the protective effect of trazodone against sleep deprivation-induced anxiety like behavior and oxidative damage in mice. Keywords: Anxiety, locomotor activity, oxidative stress, sleep deprivation, trazodone, L-arginine, L-NAME, methylene blue.

  9. Concentrated Aqueous Sodium Tosylate as Green Medium for Alkene Oxidation and Nucleophilic Substitution Reactions.

    Science.gov (United States)

    Sela, Tal; Lin, Xiaoxi; Vigalok, Arkadi

    2017-11-03

    A hydrotropic solution of highly concentrated sodium tosylate (NaOTs) can be used as a recyclable medium for the environmentally benign oxidation of conjugated alkenes with H 2 O 2 . Both uncatalyzed and metal-catalyzed reactions provided the corresponding oxidation products in higher yields than in pure water or many common organic solvents.

  10. Supercritical carbon dioxide as an innovative reaction medium for selective oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Loeker, F.; Leitner, W. [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany)

    1998-12-31

    Although the catalytic efficiency of all catalytic oxidation processes studied in scCO{sub 2} up to now is far from being satisfactory, the principle possibility to carry out such reactions in this medium is clearly evident. Future research in our group will be directed towards the development of homogeneous and heterogeneous catalysts that are adopted to the special requirements of both the oxidation process and the supercritical reaction medium. Preliminary results from these studies regarding the epoxidation of olefins with molecular oxygen as oxidant will be presented on the conference poster. (orig.)

  11. Populations of striatal medium spiny neurons encode vibrotactile frequency in rats: modulation by slow wave oscillations.

    Science.gov (United States)

    Hawking, Thomas G; Gerdjikov, Todor V

    2013-01-01

    Dorsolateral striatum (DLS) is implicated in tactile perception and receives strong projections from somatosensory cortex. However, the sensory representations encoded by striatal projection neurons are not well understood. Here we characterized the contribution of DLS to the encoding of vibrotactile information in rats by assessing striatal responses to precise frequency stimuli delivered to a single vibrissa. We applied stimuli in a frequency range (45-90 Hz) that evokes discriminable percepts and carries most of the power of vibrissa vibration elicited by a range of complex fine textures. Both medium spiny neurons and evoked potentials showed tactile responses that were modulated by slow wave oscillations. Furthermore, medium spiny neuron population responses represented stimulus frequency on par with previously reported behavioral benchmarks. Our results suggest that striatum encodes frequency information of vibrotactile stimuli which is dynamically modulated by ongoing brain state.

  12. Co3O4/reduced graphene oxide nanocomposite for removal of organic pollutants from aqueous medium

    Science.gov (United States)

    Mishra, Amodini; Kuanr, B. K.; Mohanty, T.

    2017-05-01

    The magnetic nanocomposite (MNC) of cobalt oxide/graphene oxide (Co3O4/rGO) has been synthesized by hydrothermal method to demonstrate its use as organic pollutants remover. The phase formation of the cobalt oxide magnetic nanoparticles (MNPs) has been confirmed by X-ray diffraction (XRD) analysis. The nanocomposite has been characterized by Raman spectroscopic technique and two Raman peaks associated with graphene oxide are observed. The morphological study of the nanocomposite has been done using scanning electron microscope (SEM). The nanocomposite has been used for removal of organic pollutants from aqueous medium by using ultra-violet spectroscopy.

  13. Kinetics of Oxidation of 3-Benzoylpropionic Acid by N-Bromoacetamide in Aqueous Acetic Acid Medium

    Directory of Open Access Journals (Sweden)

    N. A. Mohamed Farook

    2011-01-01

    Full Text Available The kinetics of oxidation of 3-benzoylpropionic acid (KA with N-bromoacetamide (NBA have been studied potentiometrically in 50:50 (v/v aqueous acetic acid medium at 298 K The reaction was first order each with respect to [KA], [NBA] and [H+]. The main product of the oxidation is the corresponding carboxylic acid. The rate decreases with the addition of acetamide, one of the products of the reaction. Variation in ionic strength of the reaction medium has no significant effect on the rate of oxidation. But the rate of the reaction is enhanced by lowering the dielectric constant of the reaction medium. A mechanism consistent with observed results have been proposed and the related rate law was deduced.

  14. Kinetics of Oxidation of Some Amino Acids by N-Chlorosaccharin in Aqueous Acetic Acid Medium

    Directory of Open Access Journals (Sweden)

    N. A. Mohamed Farook

    2004-01-01

    Full Text Available The kinetics of oxidation of some amino acids namely, glycine, alanine, aspartic acid, arginine, and histidine, (AA by N-chlorosaccharin (NCSA in aqueous acetic acid medium in the presence of perchloric acid have been investigated. The observed rate of oxidation is first order in [AA], [NCSA] and of inverse fractional order in [H+]. The main product of the oxidation is the corresponding aldehyde. The ionic strength on the reaction rate has no significant effect. The effect of changing the dielectric constant of the medium on the rate indicates the reaction to be of dipole-dipole type. Hypochlorous acid has been postulated as the reactive oxidizing species. The reaction constants involved in the mechanism are derived. The activation parameters are computed with respect to slow step of the mechanism.

  15. Plasmonic nanostructured metal-oxide-semiconductor reflection modulators.

    Science.gov (United States)

    Olivieri, Anthony; Chen, Chengkun; Hassan, Sa'ad; Lisicka-Skrzek, Ewa; Tait, R Niall; Berini, Pierre

    2015-04-08

    We propose a plasmonic surface that produces an electrically controlled reflectance as a high-speed intensity modulator. The device is conceived as a metal-oxide-semiconductor capacitor on silicon with its metal structured as a thin patch bearing a contiguous nanoscale grating. The metal structure serves multiple functions as a driving electrode and as a grating coupler for perpendicularly incident p-polarized light to surface plasmons supported by the patch. Modulation is produced by charging and discharging the capacitor and exploiting the carrier refraction effect in silicon along with the high sensitivity of strongly confined surface plasmons to index perturbations. The area of the modulator is set by the area of the incident beam, leading to a very compact device for a strongly focused beam (∼2.5 μm in diameter). Theoretically, the modulator can operate over a broad electrical bandwidth (tens of gigahertz) with a modulation depth of 3 to 6%, a loss of 3 to 4 dB, and an optical bandwidth of about 50 nm. About 1000 modulators can be integrated over a 50 mm(2) area producing an aggregate electro-optic modulation rate in excess of 1 Tb/s. We demonstrate experimentally modulators operating at telecommunications wavelengths, fabricated as nanostructured Au/HfO2/p-Si capacitors. The modulators break conceptually from waveguide-based devices and belong to the same class of devices as surface photodetectors and vertical cavity surface-emitting lasers.

  16. Effects of nitric oxide modulating activities on development of enteric ...

    Indian Academy of Sciences (India)

    ... the enteric neural crest-derived cells (ENCCs), and many molecules and biochemical processes may be involved in its development. This study examined the effects of modulating embryonic nitric oxide (NO) activity on the intestinal motility induced by ENS. One-hundred-and-twenty fertilized chicken eggs were assigned ...

  17. Unprecedented Selective Oxidation of Styrene Derivatives using a Supported Iron Oxide Nanocatalyst in Aqueous Medium

    Science.gov (United States)

    Iron oxide nanoparticles supported on mesoporous silica-type materials have been successfully utilized in the aqueous selective oxidation of alkenes under mild conditions using hydrogen peroxide as a green oxidant. Catalysts could be easily recovered after completion of the reac...

  18. Segmented Thermoelectric Oxide-based Module

    DEFF Research Database (Denmark)

    Le, Thanh Hung; Linderoth, Søren

    for a more stable high temperature material. In this study, thermoelectric properties from 300 to 1200 K of Ca0.9Y0.1Mn1-xFexO3 for 0 ≤ x ≤ 0.25 were systematically investigated in term of Y and Fe co-doping at the Ca- and Mn-sites, respectively. It was found that with increasing the content of Fe doping......, the Seebeck coefficient of Ca0.9Y0.1Mn1-xFexO3 tended to increase, while the tendency towards the electrical conductivity was more complicated. Thermal conductivity of the Fe-doped samples showed a lower value than that of the non-doped sample. The maximum dimensionless figure-of-merit, zT was found......Since 1990s, oxide thermoelectrics have been considered as promising thermoelectric (TE) materials due to their non-toxicity, low-cost, and chemical stability at high temperatures. Studied results show great potential for applications in thermoelectric power generator (TEG) at high temperature...

  19. [ACID-BASE MODULATION OF LYSOZYME ACTIVITY IN MEDIUM FOR CULTIVATION OF ENTEROBACTERIA].

    Science.gov (United States)

    Andryuschenko, S V; Perunova, N B

    2015-01-01

    Determination of modulating effect of acid-base state of medium for cultivation of enterobacteria on activity of C-type lysozyme. Escherichia coli BL21 (DE3) strain for protein expression, Escherichia coli K12 MG1655 model strain, Escherichia coli No. 242 strain, isolated from intestine biotope; 2 Klebsiella pneumoniae strains, one of those contained plasmid homologue of periplasmatic lysozyme inhibitor gene pliC; 1 typical Salmonella enterica ATCC 14028 strain and a Micrococcus luteus ATCC 15307 strain as a control--served as material for the study. The bacteria were cultivated for 24 hours in 2 ml of liquid medium LB at 37 degrees C, 250 rpm. Determination of antilysozyme activity (ALA) was carried out by a photonepehlometrical method according to O.V. Bukharin et al. (1999) with alterations. All the studied microorganisms, including Micrococcus luteus, at the specified conditions 24 hours after cultivation were established to change the pH of the liquid nutrient medium LB from the initial value of 6.6 ± 0.1 to 8.2 ± 0.2 units. ALA determination in the cultivation medium without buffer correction was accompanied by a decline of lysozyme activity at an order of magnitude. The effect was absent during ALA measurement by a standard technique. The local shift of acid-base state of biotope under the conditions of buffer system insufficiency results in a reversible alteration of antimicrobial activity of muramidase, that among other non-specific factors of the environment determines the background of interactions on the level of associative symbiosis. This aspect should be taken into consideration during development of models, that are close to real conditions of microsymbiocenotical interactions.

  20. Oxidation of Amitriptyline by Bromamine-T in Acidic Buffer Medium: A Kinetic and Mechanistic Approach

    OpenAIRE

    Chandrashekar; R. T. Radhika; B. M. Venkatesha; S. Ananda; Shivalingegowda; T. S. Shashikumar; H. Ramachandra

    2016-01-01

    The kinetics of the oxidation of amitriptyline (AT) by sodium N-bromotoluene sulphonamide (C6H5SO2NBrNa) has been studied in an acidic buffer medium of pH 1.2 at 303 K. The oxidation reaction of AT was followed spectrophotometrically at maximum wavelength, 410 nm. The reaction rate shows a first order dependence each on concentration of AT and concentration of sodium N-bromotoluene sulphonamide. The reaction also shows an inverse fractional order dependence at low or high concentration of HCl...

  1. Kinetics and Mechanism of Oxidation of Aromatic Aldehydes by Imidazolium Dichromate in Aqueous Acetic Acid Medium

    Directory of Open Access Journals (Sweden)

    S. Sheik Mansoor

    2009-01-01

    Full Text Available The kinetics of oxidation of benzaldehyde (BA and para-substituted benzaldehydes by imidazolium dichromate (IDC has been studied in aqueous acetic acid medium in the presence of perchloric acid. The reaction is first order each in [IDC], [Substrate] and [H+]. The reaction rates have been determined at different temperatures and the activation parameters calculated. Electron withdrawing substituents are found to increase the reaction and electron releasing substituents are found to retard the rate of the reaction and the rate data obey the Hammett relationship. The products of the oxidation are the corresponding acids. The rate decreases with the increase in the water content of the medium. A suitable mechanism is proposed.

  2. Medium-chain fatty acids undergo elongation before β-oxidation in fibroblasts

    International Nuclear Information System (INIS)

    Jones, Patricia M.; Butt, Yasmeen; Messmer, Bette; Boriak, Richard; Bennett, Michael J.

    2006-01-01

    Although mitochondrial fatty acid β-oxidation (FAO) is considered to be well understood, further elucidation of the pathway continues through evaluation of patients with FAO defects. The FAO pathway can be examined by measuring the 3-hydroxy-fatty acid (3-OHFA) intermediates. We present a unique finding in the study of this pathway: the addition of medium-chain fatty acids to the culture media of fibroblasts results in generation of 3-OHFAs which are two carbons longer than the precursor substrate. Cultured skin fibroblasts from normal and LCHAD-deficient individuals were grown in media supplemented with various chain-length fatty acids. The cell-free medium was analyzed for 3-OHFAs by stable-isotope dilution gas-chromatography/mass-spectrometry. Our finding suggests that a novel carbon chain-length elongation process precedes the oxidation of medium-chain fatty acids. This previously undescribed metabolic step may have important implications for the metabolism of medium-chain triglycerides, components in the dietary treatment of a number of disorders

  3. L-carnitine modulates blood platelet oxidative stress.

    Science.gov (United States)

    Saluk-Juszczak, Joanna; Olas, Beata; Wachowicz, Barbara; Glowacki, Rafal; Bald, Edward

    2010-08-01

    The oxidative stress induced by acute exertion may interfere with blood platelet activation. The beneficial effect of L-carnitine (gamma-trimethylamino-beta-hydroxybutyric acid) on oxidative stress in blood platelets has not been fully investigated; however, different studies indicate that this compound modulates platelet functions. The aim of our study was to assess the effects of L-carnitine on platelet activation and oxidative/nitrative protein damage (determined by the levels of protein carbonyl groups, thiol groups, and 3-nitrotyrosine residues) in resting blood platelets or platelets treated with peroxynitrite (ONOO(-), a strong physiological oxidant) in vitro. We also investigated the effects of L-carnitine on the level of platelet glutathione and on the formation of superoxide anion radicals O2(-*), lipid peroxidation measured by thiobarbituric acid reactive substances (TBARS) in blood platelets stimulated by thrombin (a strong physiological agonist), and platelet aggregation induced by adenosine diphosphate (a strong physiological stimulator). We have observed that carnitine decreases platelet activation (measured by platelet aggregation, the generation of O2(-*), and TBARS production). Moreover, our results in vitro demonstrate that carnitine may protect against oxidation of thiol groups induced by ONOO(-). Thus, carnitine may have some protectory effects against oxidative changes induced in blood platelets.

  4. Pain modulation by nitric oxide in the spinal cord.

    Directory of Open Access Journals (Sweden)

    Marco Aurelio M Freire

    2009-09-01

    Full Text Available Nitric oxide (NO is a versatile messenger molecule first associated with endothelial relaxing effects. In the central nervous system (CNS, NO synthesis is primarily triggered by activation of N-methyl-D-aspartate (NMDA receptors and has a Janus face, with both beneficial and harmful properties, depending on concentration and the identity of its synthetic enzyme isoform. There are three isoforms of the NO synthesizing enzyme nitric oxide synthase (NOS: neuronal (nNOS, endothelial (eNOS, and inducible nitric oxide synthase (iNOS, each one involved with specific events in the brain. In CNS, nNOS is involved with modulation of synaptic transmission through long-term potentiation in several regions, including nociceptive circuits in the spinal cord. Here, we review the role played by NO on central pain sensitization.

  5. Inhibition of E. coli Growth by Nanodiamond and Graphene Oxide Enhanced by Luria-Bertani Medium

    Directory of Open Access Journals (Sweden)

    Jaroslav Jira

    2018-03-01

    Full Text Available Nanodiamonds (NDs and graphene oxide (GO are modern carbon-based nanomaterials with promising features for the inhibition of microorganism growth ability. Here we compare the effects of nanodiamond and graphene oxide in both annealed (oxidized and reduced (hydrogenated forms in two types of cultivation media—Luria-Bertani (LB and Mueller-Hinton (MH broths. The comparison shows that the number of colony forming unit (CFU of Escherichia coli is significantly lowered (45% by all the nanomaterials in LB medium for at least 24 h against control. On the contrary, a significant long-term inhibition of E. coli growth (by 45% in the MH medium is provided only by hydrogenated NDs terminated with C-HX groups. The use of salty agars did not enhance the inhibition effects of nanomaterials used, i.e. disruption of bacterial membrane or differences in ionic concentrations do not play any role in bactericidal effects of nanomaterials used. The specific role of the ND and GO on the enhancement of the oxidative stress of bacteria or possible wrapping bacteria by GO nanosheets, therefore isolating them from both the environment and nutrition was suggested. Analyses by infrared spectroscopy, photoelectron spectroscopy, scanning electron microscopy and dynamic light scattering corroborate these conclusions.

  6. Inhibition of E. coli Growth by Nanodiamond and Graphene Oxide Enhanced by Luria-Bertani Medium.

    Science.gov (United States)

    Jira, Jaroslav; Rezek, Bohuslav; Kriha, Vitezslav; Artemenko, Anna; Matolínová, Iva; Skakalova, Viera; Stenclova, Pavla; Kromka, Alexander

    2018-03-01

    Nanodiamonds (NDs) and graphene oxide (GO) are modern carbon-based nanomaterials with promising features for the inhibition of microorganism growth ability. Here we compare the effects of nanodiamond and graphene oxide in both annealed (oxidized) and reduced (hydrogenated) forms in two types of cultivation media-Luria-Bertani (LB) and Mueller-Hinton (MH) broths. The comparison shows that the number of colony forming unit (CFU) of Escherichia coli is significantly lowered (45%) by all the nanomaterials in LB medium for at least 24 h against control. On the contrary, a significant long-term inhibition of E. coli growth (by 45%) in the MH medium is provided only by hydrogenated NDs terminated with C-H X groups. The use of salty agars did not enhance the inhibition effects of nanomaterials used, i.e. disruption of bacterial membrane or differences in ionic concentrations do not play any role in bactericidal effects of nanomaterials used. The specific role of the ND and GO on the enhancement of the oxidative stress of bacteria or possible wrapping bacteria by GO nanosheets, therefore isolating them from both the environment and nutrition was suggested. Analyses by infrared spectroscopy, photoelectron spectroscopy, scanning electron microscopy and dynamic light scattering corroborate these conclusions.

  7. Mechanistic study of nickel based catalysts for oxygen evolution and methanol oxidation in alkaline medium

    Science.gov (United States)

    Chen, Dayi; Minteer, Shelley D.

    2015-06-01

    Nickel based catalysts have been studied as catalysts for either organic compound (especially methanol) oxidation or oxygen evolution reactions in alkaline medium for decades, but methanol oxidation and oxygen evolution reactions occur at a similar potential range and pH with nickel based catalysts. In contrast to previous studies, we studied these two reactions simultaneously under various pH and methanol concentrations with electrodes containing a series of NiOOH surface concentrations. We found that nickel based catalysts are more suitable to be used as oxygen evolution catalysts than methanol oxidation catalysts based on the observation that: The rate-determining step of methanol oxidation involves NiOOH, OH- and methanol while high methanol to OH- ratio could poison the NiOOH sites. Since NiOOH is involved in the rate-determining step, methanol oxidation suffers from high overpotential and oxygen evolution is favored over methanol oxidation in the presence of an equivalent amount (0.1 M) of alkali and methanol.

  8. High resolution medium energy ion scattering study of silicon oxidation and oxy nitridation

    International Nuclear Information System (INIS)

    Gusev, E.P.; Lu, H.C.; Garfunkel, E.; Gustafsson, T.

    1998-01-01

    Full text: Silicon oxide is likely to remain the material of choice for gate oxides in microelectronics for the foreseeable future. As device become ever smaller and faster, the thickness of these layers in commercial products is predicted to be less than 50 Angstroms in just a few years. An understanding of such devices will therefore likely to be based on microscopic concepts and should now be investigated by atomistic techniques. With medium energy ion scattering (MEIS) using an electrostatic energy analyzer, depth profiling of thin (<60 Angstroms) silicon oxide films on Si(100) with 3 - 5 Angstroms depth resolution in the near region has been done. The growth mechanism of thin oxide films on Si(100) has been studied, using sequential oxygen isotope exposures. It is found that the oxide films are stoichiometric to within approx. 10 Angstroms of the interface. It is also found that the oxidation reactions occur at the surface, in the transition region and at interface, with only the third region being included in the conventional (Deal-Grove) model for oxide formation. Nitrogen is sometimes added to gate oxides, as it has been found empirically that his improves some of the electrical properties. The role, location and even the amount of nitrogen that exists in such films are poorly understood, and represent interesting analytical challenges. MEIS data will be presented that address these questions, measured for a number of different processing conditions. We have recently demonstrated how to perform nitrogen nano-engineering in such ultrathin gate dielectrics, and these results will also be discussed

  9. Oxidation of Tetracaine Hydrochloride by Chloramine-B in Acid Medium: Kinetic Modeling

    Directory of Open Access Journals (Sweden)

    Jayachamarajapura Pranesh Shubha

    2014-01-01

    Full Text Available Tetracaine hydrochloride (TCH is one of the potent local anaesthetics. A kinetic study of oxidation of tetracaine hydrochloride by sodium N-chlorobenzenesulfonamide (chloramine-B or CAB has been carried in HClO4 medium at 303 K. The rate shows first-order dependence on [CAB]o, shows fractional–order dependence on [substrate]o, and is self-governing on acid concentration. Decrease of dielectric constant of the medium, by adding methanol, increased the rate. Variation of ionic strength and addition of benzenesulfonamide or NaCl have no significant effect on the rate. The reaction was studied at different temperatures and the activation parameters have been evaluated. The stoichiometry of the reaction was found to be 1 : 5 and the oxidation products were identified by spectral analysis. The conjugate free acid C6H5SO2NHCl of CAB is postulated as the reactive oxidizing species. The observed results have been explained by plausible mechanism and the related rate law has been deduced.

  10. A spectroelectrochemical and chemical study on oxidation of hydroxycinnamic acids in aprotic medium

    Energy Technology Data Exchange (ETDEWEB)

    Petrucci, Rita [Dipartimento di Ingegneria Chimica M.M.P.M., Universita di Roma ' La Sapienza' , via del Castro Laurenziano 7, I-00161 Rome (Italy)]. E-mail: rita.petrucci@uniroma1.it; Astolfi, Paola [Dipartimento di Scienze dei Materiali e della Terra, Universita Politecnica delle Marche, via Brecce Bianche, I-60131 Ancona (Italy); Greci, Lucedio [Dipartimento di Scienze dei Materiali e della Terra, Universita Politecnica delle Marche, via Brecce Bianche, I-60131 Ancona (Italy); Firuzi, Omidreza [Dipartimento di Farmacologia delle Sostanze Naturali e Fisiologia Generale, Universita di Roma ' La Sapienza' , p.le Aldo Moro 5, I-00185 Rome (Italy); Saso, Luciano [Dipartimento di Farmacologia delle Sostanze Naturali e Fisiologia Generale, Universita di Roma ' La Sapienza' , p.le Aldo Moro 5, I-00185 Rome (Italy); Marrosu, Giancarlo [Dipartimento di Ingegneria Chimica M.M.P.M., Universita di Roma ' La Sapienza' , via del Castro Laurenziano 7, I-00161 Rome (Italy)

    2007-02-01

    Electrochemical and chemical oxidation of hydroxycinnamic acids (HCAs) was studied to investigate the mechanisms occurring in their antioxidant activities in a protons poor medium. Electrolyses and chemical reactions were followed on-line by monitoring the UV-spectral changes with time; final solutions were analysed by HPLC-MS. Anodic oxidation of mono- and di-HCAs, studied by cyclic voltammetry and controlled potential electrolyses, occurs via a reversible one-step two-electrons process, yielding the corresponding stable phenoxonium cation. A cyclization product was also proposed, as supported by ESR studies. Chemical oxidation with lead dioxide leads to different oxidation products according to the starting substrate. Di-HCAs like chlorogenic and rosmarinic acids and the ethyl ester of caffeic acid gave the corresponding neutral o-quinones, while mono-HCAs like cumaric, ferulic and sinapinic acids yielded the corresponding unstable neutral phenoxyl radical, as supported by the formation of dimerization products evidenced by HPLC-MS. In the case of caffeic acid, traces of the dimerization product suggest that the neutral phenoxyl radical may competitively undergo dimerization or decomposition of the neutral quinone. Chemical oxidation of HCAs was also followed by ESR spectroscopy: the di-HCAs radical anions were generated and detected, whereas among the mono-HCAs only the phenoxyl radical of the sinapinic acid was recorded.

  11. Degeneration modulates retinal response to transient exogenous oxidative injury.

    Directory of Open Access Journals (Sweden)

    Michal Lederman

    Full Text Available Oxidative injury is involved in retinal and macular degeneration. We aim to assess if retinal degeneration associated with genetic defect modulates the retinal threshold for encountering additional oxidative challenges.Retinal oxidative injury was induced in degenerating retinas (rd10 and in control mice (WT by intravitreal injections of paraquat (PQ. Retinal function and structure was evaluated by electroretinogram (ERG and histology, respectively. Oxidative injury was assessed by immunohistochemistry for 4-Hydroxy-2-nonenal (HNE, and by Thiobarbituric Acid Reactive Substances (TBARS and protein carbonyl content (PCC assays. Anti-oxidant mechanism was assessed by quantitative real time PCR (QPCR for mRNA of antioxidant genes and genes related to iron metabolism, and by catalase activity assay.Three days following PQ injections (1 µl of 0.25, 0.75, and 2 mM the average ERG amplitudes decreased more in the WT mice compared with the rd10 mice. For example, following 2 mM PQ injection, ERG amplitudes reduced 1.84-fold more in WT compared with rd10 mice (p = 0.02. Injection of 4 mM PQ resulted in retinal destruction. Altered retina morphology associated with PQ was substantially more severe in WT eyes compared with rd10 eyes. Oxidative injury according to HNE staining and TBARS assay increased 1.3-fold and 2.1-fold more, respectively, in WT compared with rd10 mice. At baseline, prior to PQ injection, mRNA levels of antioxidant genes (Superoxide Dismutase1, Glutathione Peroxidase1, Catalase and of Transferrin measured by quantitative PCR were 2.1-7.8-fold higher in rd10 compared with WT mice (p<0.01 each, and catalase activity was 1.7-fold higher in rd10 (p = 0.0006.This data suggests that degenerating rd10 retinas encounter a relatively lower degree of damage in response to oxidative injury compared with normal retinas. Constitutive up-regulation of the oxidative defense mechanism in degenerating retinas may confer such relative protection from

  12. Studies on the oxidizing system in Holt's medium for histochemical demonstration of esterase activity

    DEFF Research Database (Denmark)

    Kirkeby, S; Blecher, S R

    1978-01-01

    Esterase activity in guinea-pig thyroid and mouse epididymis epithelial cells has been studied using 5-bromoindoxyl acetate as substrate. The pattern of esterase activity in the thyroid of the guinea-pig is constant, irrespective of whether ferri-ferrocyanide (FFC) or certain copper compounds...... cells contain an esterase activity which is not inhibited by conventional SH blocking agents, nor by high concentrations of FFC. From these results it appears that the mode of action of FFC in Holt's medium is as follows. At low concentrations FFC appears to act primarily as a catalytic agent...... in oxidation of indoxyl to indigoid. At high concentration FFC acts as an inhibitor of guinea-pig thyroid esterase, by oxidation of SH groups in the active centre. The esterase of mouse epididymis cell type EH 1 is not subject to this inhibition by FFC, presumably because it does not contain accessible SH...

  13. Electrochemical oxidation of loop diuretic furosemide in aqueous acid medium and its analytical application

    Directory of Open Access Journals (Sweden)

    Shikandar D. Bukkitgar

    2016-12-01

    Full Text Available An investigation of oxidative–reductive mechanisms of pharmaceutically important molecules gives us information about the metabolic fact of targeted drug. As compared to recent ongoing, time-consuming and costly techniques, there is an urgent needing for development of a sensitive technique, which can help easy understanding of these pathways. Therefore, in the present work, an effective, low-cost and time-saving technique to investigate the reaction mechanism of furosemide in aqueous acid medium is attempted. Furosemide undergoes two-proton and two-electron transfer reaction. The product obtained was analysed by UV spectra. It was found that the chemical oxidation and electrochemical oxidation of furosemide follows two different pathways. In addition, an effective technique has been developed to determine furosemide in its trace level. Good recoveries and low detection limit accomplished the magnitude of the proposed method. The proposed method was adopted for furosemide determination in human urine and pharmaceutical samples.

  14. Effects of oxidizing medium on the composition, morphology and optical properties of copper oxide nanoparticles produced by pulsed laser ablation

    KAUST Repository

    Gondal, M. A.

    2013-12-01

    Pulsed laser ablation in liquid (PLAL) with 532 nm wavelength laser with 5 ns pulse duration is used to produce the nanostructure copper oxide and the effects of oxidizing media (deionized water and hydrogen peroxide) on the composition, morphology and optical properties of the product materials produced by PLAL were studied. XRD and TEM studies indicate that in the absence of hydrogen peroxide, the product material is in two phases (Cu/Cu2O) with the spherical nanoparticle structure, whereas in the presence of hydrogen peroxide in the liquid medium, the product material revealed other two phases (Cu/CuO) with nanorod-like structure. The optical studies revealed a considerable red shift (3.34-2.5 eV) in the band gap energy in the case of hydrogen peroxide in the liquid medium in PLAL synthesis compared to the one in the absence of it. Also the product material in the presence of hydrogen peroxide in the liquid medium showed a reduced photoluminescence intensity indicating the reduced electron-hole recombination rate. The red shift in the band gap energy and the reduced electron-hole recombination rate make the product material an ideal photocatalyst to harvest solar radiation for various applications. The most relevant signals on the FTIR spectrum for the samples are the absorption bands in the region between 450 and 700 cm-1 which are the characteristics bands of copperoxygen bonds. The reported laser ablation approach for the synthesis of Cu2O and CuO nanoparticles has the advantages of being clean method with controlled particle properties. © 2013 Elsevier B.V. All rights reserved.

  15. Modulation of medium pH by Caulobacter crescentus facilitates recovery from uranium-induced growth arrest.

    Science.gov (United States)

    Park, Dan M; Jiao, Yongqin

    2014-09-01

    The oxidized form of uranium [U(VI)] predominates in oxic environments and poses a major threat to ecosystems. Due to its ability to mineralize U(VI), the oligotroph Caulobacter crescentus is an attractive candidate for U(VI) bioremediation. However, the physiological basis for U(VI) tolerance is unclear. Here we demonstrated that U(VI) caused a temporary growth arrest in C. crescentus and three other bacterial species, although the duration of growth arrest was significantly shorter for C. crescentus. During the majority of the growth arrest period, cell morphology was unaltered and DNA replication initiation was inhibited. However, during the transition from growth arrest to exponential phase, cells with shorter stalks were observed, suggesting a decoupling between stalk development and the cell cycle. Upon recovery from growth arrest, C. crescentus proliferated with a growth rate comparable to that of a control without U(VI), although a fraction of these cells appeared filamentous with multiple replication start sites. Normal cell morphology was restored by the end of exponential phase. Cells did not accumulate U(VI) resistance mutations during the prolonged growth arrest, but rather, a reduction in U(VI) toxicity occurred concomitantly with an increase in medium pH. Together, these data suggest that C. crescentus recovers from U(VI)-induced growth arrest by reducing U(VI) toxicity through pH modulation. Our finding represents a unique U(VI) detoxification strategy and provides insight into how microbes cope with U(VI) under nongrowing conditions, a metabolic state that is prevalent in natural environments. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  16. Microwave-assisted pechini synthesis of Pd-Ni nanocatalyst for ethanol electro-oxidation in alkaline medium

    CSIR Research Space (South Africa)

    Rohwer, M

    2012-11-01

    Full Text Available counterparts. For these reasons, electrocatalysts for the oxidation of ethanol in alkaline medium deserve special attention. Pd and its alloys, e.g. Pd-Ni, have been investigated widely as catalysts for ethanol electro-oxidation, and form the subject...

  17. Kinetic Studies on the Selective Oxidation of Benzyl Alcohols in Organic Medium under Phase Transfer Catalysis

    Directory of Open Access Journals (Sweden)

    K. Bijudas

    2014-07-01

    Full Text Available Kinetic studies on the oxidation of benzyl alcohol and substituted benzyl alcohols in benzene as the reaction medium have been studied by using potassium dichromate under phase transfer catalysis (PTC. The phase transfer catalysts (PT catalysts used were tetrabutylammonium bromide (TBAB and tetrabutylphosphonium bromide (TBPB.  Benzyl alcohols were selectively oxidised to corresponding benzaldehydes in good yield (above 90%.  The order of reactivity among the studied benzyl alcohols is p - OCH3 > p - CH3 > - H > p - Cl.  Plots of log k2 versus Hammett's substituent constant (s has been found to be curve shaped and this suggests that there should be a continuous change in transition state with changes in substituent present in the substrate from electron donating to electron withdrawing. A suitable mechanism has been suggested in which the rate determining step involves both C - H bond cleavage and C - O bond formations in concerted manner. © 2014 BCREC UNDIP. All rights reserved.Received: 16th March 2014; Revised: 18th May 2014; Accepted: 18th May 2014[How to Cite: Bijudas, K., Bashpa, P., Nair, T.D.R. (2014. Kinetic Studies on the Selective Oxidation of Benzyl Alcohol and Substituted Benzyl Alcohols in Organic Medium under Phase Transfer Catalysis. Bulletin of Chemical Reaction Engineering & Catalysis, 9 (2: 142-147. (doi:10.9767/bcrec.9.2.6476.142-147][Permalink/DOI: http://dx.doi.org/10.9767/bcrec.9.2.6476.142-147] 

  18. Spectroscopic and mechanistic investigations into oxidation of aspartame by diperiodatocuprate(III in aqueous alkaline medium

    Directory of Open Access Journals (Sweden)

    Jayant I. Gowda

    2015-12-01

    Full Text Available The oxidation of aspartame (ASP by diperiodatocuprate(III (DPC in aqueous alkaline medium at 298 K and a constant ionic strength of 0.30 mol dm−3 was studied spectrophotometrically. The reaction between aspartame and diperiodatocuprate(III in alkaline medium exhibits 1:6 stoichiometry in the reaction. The order of the reaction with respect to [diperiodatocuprate(III] was unity, while the apparent order with respect to [aspartame] was less than unity over the concentration range studied. The rate of the reaction increased with increase in [OH−] whereas the rate decreased with increase in [$ {\\text{IO}}^-_4 $]. Increasing the ionic strength of the medium increased the rate. The main products were identified by FT-IR, NMR, and LC-MS spectral studies. The probable mechanism was proposed. The activation parameters with respect to slow step of the mechanism were computed and discussed. Thermodynamic quantities were also calculated. Kinetic studies suggest that [Cu(H2IO6(H2O2] is the reactive species of Cu(III.

  19. Concretionary manganese-iron oxides in streams and their usefulness as a sample medium for geochemical prospecting

    Science.gov (United States)

    Nowlan, G.A.

    1976-01-01

    Correlation studies of 400 samples of sieved stream sediments and 325 samples of fluvial, concretionary Mn-Fe oxides from Maine resulted in the separation of elements into the following categories: (1) elements not scavenged by Mn-Fe oxides - B, Cr, K, Mg, Rb, Sc, Ti, V, and Zr; (2) elements probably not scavenged by Mn-Fe oxides - Ag, Be, Ca, Ga, La, Sb, and Y; (3) elements scavenged weakly by Mn-Fe oxides - Cu, Mo, Pb, and Sr; (4) elements scavenged strongly by Mn oxides - Ba, Cd, Co, Ni, Tl, and Zn; and (5) elements scavenged strongly by Fe oxides - As and In. Studies of the scavenged elements showed that the deviation from the mean is characteristically greater in oxide samples as compared to sieved sediments from the same locality. However, a significant increase in contrast between anomalous and background localities, when oxides are the sample medium, more than offsets the disadvantage of data scatter. The use of oxides as a sampling medium clearly and significantly accentuates anomalous localities. In general, non-ratioed data on oxides give very nearly the same results as data consisting of scavenged elements ratioed to Mn and Fe. However, ratioed data expand the geographic area of specific anomalies. Cd and Zn consistently show strong correlations with concretionary Mn-Fe oxides, but their concentrations in the oxides do not generally show as much contrast between anomalous and background localities as do Cu, Mo, and Pb. These latter elements are strongly scavenged where rocks are mineralized. ?? 1976.

  20. Kinetics and Mechanistic Study of Permanganate Oxidation of Fluorenone Hydrazone in Alkaline Medium

    Directory of Open Access Journals (Sweden)

    Ahmed Fawzy

    2016-01-01

    Full Text Available The oxidation kinetics of fluorenone hydrazone (FH using potassium permanganate in alkaline medium were measured at a constant ionic strength of 0.1 mol dm−3 and at 25°C using UV/VIS spectrophotometer. A first-order kinetics has been monitored in the reaction of FH with respect to [permanganate]. Less-than-unit order dependence of the reaction on [FH] and [OH−] was revealed. No pronounced effect on the reaction rate by increasing ionic strength was recorded. Intervention of free radicals was observed in the reaction. The reaction mechanism describing the kinetic results was illustrated which involves formation of 1 : 1 intermediate complex between fluorenone hydrazones and the active species of permanganate. 9H-Fluorenone as the corresponding ketone was found to be the final oxidation product of fluorenone hydrazone as confirmed by GC/MS analysis and FT-IR spectroscopy. The expression rate law for the oxidation reaction was deduced. The reaction constants and mechanism have been evaluated. The activation parameters associated with the rate-limiting step of the reaction, along with the thermodynamic quantities of the equilibrium constants, have been calculated and discussed.

  1. Differential modulation of nitric oxide synthases in aging: therapeutic opportunities

    Directory of Open Access Journals (Sweden)

    Stêfany Bruno De Assis Cau

    2012-06-01

    Full Text Available Vascular aging is the term that describes the structural and functional disturbances of the vasculature with advancing aging. The molecular mechanisms of aging-associated endothelial dysfunction are complex, but reduced nitric oxide (NO bioavailability and altered vascular expression and activity of NO synthase (NOS enzymes have been implicated as major players. Impaired vascular relaxation in aging has been attributed to reduced endothelial NOS (eNOS-derived NO, while increased inducible NOS (iNOS expression seems to account for nitrosative stress and disrupted vascular homeostasis. Although eNOS is considered the main source of NO in the vascular endothelium, neuronal NOS (nNOS also contributes to endothelial cells-derived NO, a mechanism that is reduced in aging. Pharmacological modulation of NO generation and expression/activity of NOS isoforms may represent a therapeutic alternative to prevent the progression of cardiovascular diseases. Accordingly, this review will focus on drugs that modulate NO bioavailability, such as nitrite anions and NO-releasing non-steroidal anti-inflammatory drugs, hormones (dehydroepiandrosterone and estrogen, statins, resveratrol and folic acid, since they may be useful to treat/to prevent aging-associated vascular dysfunction. The impact of these therapies on life quality in elderly and longevity will be discussed.

  2. Transparent conducting oxides for electro-optical plasmonic modulators

    Directory of Open Access Journals (Sweden)

    Babicheva Viktoriia E.

    2015-06-01

    Full Text Available The ongoing quest for ultra-compact optical devices has reached a bottleneck due to the diffraction limit in conventional photonics. New approaches that provide subwavelength optical elements, and therefore lead to miniaturization of the entire photonic circuit, are urgently required. Plasmonics, which combines nanoscale light confinement and optical-speed processing of signals, has the potential to enable the next generation of hybrid information-processing devices, which are superior to the current photonic dielectric components in terms of speed and compactness. New plasmonic materials (other than metals, or optical materials with metal-like behavior, have recently attracted a lot of attention due to the promise they hold to enable low-loss, tunable, CMOScompatible devices for photonic technologies. In this review, we provide a systematic overview of various compact optical modulator designs that utilize a class of the most promising new materials as the active layer or core— namely, transparent conducting oxides. Such modulators can be made low-loss, compact, and exhibit high tunability while offering low cost and compatibility with existing semiconductor technologies. A detailed analysis of different configurations and their working characteristics, such as their extinction ratio, compactness, bandwidth, and losses, is performed identifying the most promising designs.

  3. Graphene Oxide as a Carbocatalyst for a Diels-Alder Reaction in an Aqueous Medium.

    Science.gov (United States)

    Girish, Yarabhally R; Pandit, Subrata; Pandit, Subhendu; De, Mrinmoy

    2017-09-19

    The Diels-Alder (DA) reaction, a [4+2] cycloaddition reaction, is highly important in synthetic organic chemistry and is frequently used in the synthesis of natural products containing six-membered rings. Herein, we report an efficient protocol for the DA reaction between 9-hydroxymethylanthracene and N-substituted maleimides using two-dimensional graphene oxide (GO) as a heterogeneous carbocatalyst in an aqueous medium at room temperature. High yields, a wide substrate scope, low temperature, excellent functional group tolerance, atom economy, and water as a green solvent are noteworthy features of this protocol. The heterogeneous GO catalyst can be easily recovered and used multiple times without any significant loss in catalytic activity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. High electrocatalytic performance of nitrogen-doped carbon nanofiber-supported nickel oxide nanocomposite for methanol oxidation in alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Al-Enizi, Abdullah M. [Department of Chemistry, King Saud University, PO Box: 2455, Riyadh 11451 (Saudi Arabia); Elzatahry, Ahmed A., E-mail: aelzatahry@ksu.edu.sa [Materials Science and Technology Program, College of Arts and Science, Qatar University, Doha 2713 (Qatar); Advanced Technology and New Materials Research Institute, City of Scientific Research and Technology Applications, New Borg El-Arab City, Alexandria 21934 (Egypt); Abdullah, Aboubakr M., E-mail: bakr@qu.edu.qa [Center for Advanced Materials, Qatar University, Doha 2713 (Qatar); Vinu, Ajayan [Future Industries Institute, University of South Australia, Building X-X2-09, Mawson Lakes Campus, Mawson Lakes 5095 SA (Australia); Iwai, Hideo [Materials Analysis Station, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki, 305-0047 (Japan); Al-Deyab, Salem S. [Petrochemical Research Chair, Department of Chemistry, King Saud University, PO Box: 2455, Riyadh 11451 (Saudi Arabia)

    2017-04-15

    Highlights: • A mixture of Polyvinylpyrrolidone (PVP), graphene and emeraldine base polyaniline (PANi) was electrospun and used as starting materials to prepare a nitrogen-doped carbon nanofiber (N-CNF). • Nickel oxide was loaded on the N-CNF to form a nanocomposite which was calcined later at different temperatures. • The effect of calcination temperature on the electrocatalytic behavior of the nanocomposite was studied which shows that the nanocomposite calcined at 500 °C was proved to be very high compared to the other calcination temperatures. • The stability of catalyst was excellent and its resistance to the adsorption of the intermediates generated from the methanol oxidation was very high. - Abstract: Nitrogen-Doped Carbon Nanofiber (N-CNF)–supported NiO composite was prepared by electrospinning a sol-gel mixture of graphene and polyaniline (PANi) with aqueous solutions of Polyvinylpyrrolidone (PVP) followed by a high-temperature annealing process. The electrospun was stabilized for 2 h at 280 °C, carbonized for 5 h at 1200 °C then loaded by 10% NiO. The electrocatalytic activities of the produced nanocomposite have been studied using cyclic voltammetry, and chronoamperometry. Also, N-CNF was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), surface area (BET), X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and scanning-electron microscopy (SEM). The obtained N-doped carbon nanofiber was found to have a nitrogen content of 2.6 atomic% with a diameter range of (140–160) nm, and a surface area (393.3 m{sup 2} g{sup −1}). In addition, it showed a high electrocatalytic behavior towards methanol oxidation reaction in alkaline medium and high stability and resistivity to the adsorption of intermediates.

  5. Conifer somatic embryogenesis: improvements by supplementation of medium with oxidation-reduction agents.

    Science.gov (United States)

    Pullman, Gerald S; Zeng, Xiaoyan; Copeland-Kamp, Brandi; Crockett, Jonathan; Lucrezi, Jacob; May, Sheldon W; Bucalo, Kylie

    2015-02-01

    A major barrier to the commercialization of somatic embryogenesis technology in loblolly pine (Pinus taeda L.) is recalcitrance of some high-value crosses to initiate embryogenic tissue (ET) and continue early-stage somatic embryo growth. Developing initiation and multiplication media that resemble the seed environment has been shown to decrease this recalcitrance. Glutathione (GSH), glutathione disulfide (GSSG), ascorbic acid and dehydroascorbate analyses were performed weekly throughout the sequence of seed development for female gametophyte and zygotic embryo tissues to determine physiological concentrations. Major differences in stage-specific oxidation-reduction (redox) agents were observed. A simple bioassay was used to evaluate potential growth-promotion of natural and inorganic redox agents added to early-stage somatic embryo growth medium. Compounds showing statistically significant increases in early-stage embryo growth were then tested for the ability to increase initiation of loblolly pine. Low-cost reducing agents sodium dithionite and sodium thiosulfate increased ET initiation for loblolly pine and Douglas fir (Mirb) Franco. Germination medium supplementation with GSSG increased somatic embryo germination. Early-stage somatic embryos grown on medium with or without sodium thiosulfate did not differ in GSH or GSSG content, suggesting that sodium thiosulfate-mediated growth stimulation does not involve GSH or GSSG. We have developed information demonstrating that alteration of the redox environment in vitro can improve ET initiation, early-stage embryo development and somatic embryo germination in loblolly pine. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Engineer Medium and Feed for Modulating N-Glycosylation of Recombinant Protein Production in CHO Cell Culture.

    Science.gov (United States)

    Fan, Yuzhou; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2017-01-01

    Chinese hamster ovary (CHO) cells have become the primary expression system for the production of complex recombinant proteins due to their long-term success in industrial scale production and generating appropriate protein N-glycans similar to that of humans. Control and optimization of protein N-glycosylation is crucial, as the structure of N-glycans can largely influence both biological and physicochemical properties of recombinant proteins. Protein N-glycosylation in CHO cell culture can be controlled and tuned by engineering medium, feed, culture process, as well as genetic elements of the cell. In this chapter, we will focus on how to carry out experiments for N-glycosylation modulation through medium and feed optimization. The workflow and typical methods involved in the experiment process will be presented.

  7. Carbon supported Pd-Sn and Pd-Ru-Sn nanocatalysts for ethanol electro-oxidation in alkaline medium

    CSIR Research Space (South Africa)

    Modibedi, RM

    2011-04-01

    Full Text Available Carbon supported Pd-Sn and Pd-Ru-Sn nanocatalysts were prepared by the chemical reduction method, using sodium borohydride and ethylene glycol mixture as the reducing agent. The catalytic activity towards ethanol electro-oxidation in alkaline medium...

  8. Electrochemical behaviour of metal hexacyanoferrate converted to metal hydroxide films immobilized on indium tin oxide electrodes-Catalytic ability towards alcohol oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Ganesh, V.; Latha Maheswari, D.; Berchmans, Sheela

    2011-01-01

    Graphical abstract: - Abstract: In this work, we demonstrate a simple method to modify indium tin oxide (ITO) electrodes in order to perform electro-catalytic oxidation of alcohols in alkaline medium. Metal hexacyanoferrate (MHCF) films such as nickel hexacyanoferrate (NiHCF) and copper hexacyanoferrate (CuHCF) were successfully immobilized on ITO electrodes using an electrochemical method. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the structural and morphological aspects of MHCF films. Cyclic voltammetry (CV) was used to study the redox properties and to determine the surface coverage of these films on ITO electrodes. Electrochemical potential cycling was carried out in alkaline medium in order to alter the chemical structure of these films and convert to their corresponding metal hydroxide films. SEM and XPS were performed to analyze the structure and morphology of metal hydroxide modified electrodes. Electro-catalytic oxidation ability of these films towards methanol and ethanol in alkaline medium was investigated using CV. From these studies we found that metal hydroxide modified electrodes show a better catalytic performance and good stability for methanol oxidation along with the alleviation of CO poisoning effect. We have obtained an anodic oxidation current density of ∼82 mA cm -2 for methanol oxidation, which is at least 10 fold higher than that of any metal hydroxide modified electrodes reported till date. The onset potential for methanol oxidation is lowered by ∼200 mV compared to other chemically modified electrodes reported. A plausible mechanism was proposed for the alcohol oxidation based on the redox properties of these modified electrodes. The methodology adapted in this work does not contain costlier noble metals like platinum and ruthenium and is economically viable.

  9. Control of lignin solubility and particle formation modulates its antioxidant efficiency in lipid medium

    DEFF Research Database (Denmark)

    Barsberg, Søren Talbro; Thygesen, Lisbeth Garbrecht; Sanadi, Anand Ramesh

    2014-01-01

    Lignin is an abundant plant polymer usually regarded as waste material. In the present work, antioxidant properties of lignin preparations with differing lipid solubility were studied using biodiesel as a convenient lipid test substrate. In place of formerly used assays, we used attenuated total ...... lignin fractions. It was found that solubility and particle formation of lignin preparations strongly modulate its antioxidant efficiency and that these properties might depend on the presence of lipid components within the original lignin source....

  10. TP53 Modulates Oxidative Stress in Gata1+ Erythroid Cells

    Directory of Open Access Journals (Sweden)

    Ashley C. Kramer

    2017-02-01

    Full Text Available Metabolism of oxidative stress is necessary for cellular survival. We have previously utilized the zebrafish as a model of the oxidative stress response. In this study, we found that gata1-expressing erythroid cells contributed to a significant proportion of total-body oxidative stress when animals were exposed to a strong pro-oxidant. RNA-seq of zebrafish under oxidative stress revealed the induction of tp53. Zebrafish carrying tp53 with a mutation in its DNA-binding domain were acutely sensitive to pro-oxidant exposure and displayed significant reactive oxygen species (ROS and tp53-independent erythroid cell death resulting in an edematous phenotype. We found that a major contributing factor to ROS was increased basal mitochondrial respiratory rate without reserve. These data add to the concept that tp53, while classically a tumor suppressor and cell-cycle regulator, has additional roles in controlling cellular oxidative stress.

  11. Dietary Modulation of Oxidative Stress in Alzheimer’s Disease

    Directory of Open Access Journals (Sweden)

    Arjun Thapa

    2017-07-01

    Full Text Available Cells generate unpaired electrons, typically via oxygen- or nitrogen-based by-products during normal cellular respiration and under stressed situations. These pro-oxidant molecules are highly unstable and may oxidize surrounding cellular macromolecules. Under normal conditions, the reactive oxygen or nitrogen species can be beneficial to cell survival and function by destroying and degrading pathogens or antigens. However, excessive generation and accumulation of the reactive pro-oxidant species over time can damage proteins, lipids, carbohydrates, and nucleic acids. Over time, this oxidative stress can contribute to a range of aging-related degenerative diseases such as cancer, diabetes, macular degeneration, and Alzheimer’s, and Parkinson’s diseases. It is well accepted that natural compounds, including vitamins A, C, and E, β-carotene, and minerals found in fruits and vegetables are powerful anti-oxidants that offer health benefits against several different oxidative stress induced degenerative diseases, including Alzheimer’s disease (AD. There is increasing interest in developing anti-oxidative therapeutics to prevent AD. There are contradictory and inconsistent reports on the possible benefits of anti-oxidative supplements; however, fruits and vegetables enriched with multiple anti-oxidants (e.g., flavonoids and polyphenols and minerals may be highly effective in attenuating the harmful effects of oxidative stress. As the physiological activation of either protective or destructive pro-oxidant behavior remains relatively unclear, it is not straightforward to relate the efficacy of dietary anti-oxidants in disease prevention. Here, we review oxidative stress mediated toxicity associated with AD and highlight the modulatory roles of natural dietary anti-oxidants in preventing AD.

  12. An exogenous source of nitric oxide modulates zinc nutritional status in wheat plants.

    Science.gov (United States)

    Buet, Agustina; Moriconi, Jorge I; Santa-María, Guillermo E; Simontacchi, Marcela

    2014-10-01

    The effect of addition of the nitric oxide donor S-nitrosoglutathione (GSNO) on the Zn nutritional status was evaluated in hydroponically-cultured wheat plants (Triticum aestivum cv. Chinese Spring). Addition of GSNO in Zn-deprived plants did not modify biomass accumulation but accelerated leaf senescence in a mode concomitant with accelerated decrease of Zn allocation to shoots. In well-supplied plants, Zn concentration in both roots and shoots declined due to long term exposure to GSNO. A further evaluation of net Zn uptake rate (ZnNUR) during the recovery of long-term Zn-deprivation unveiled that enhanced Zn-accumulation was partially blocked when GSNO was present in the uptake medium. This effect on uptake was mainly associated with a change of Zn translocation to shoots. Our results suggest a role for GSNO in the modulation of Zn uptake and in root-to-shoot translocation during the transition from deficient to sufficient levels of Zn-supply. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  13. Microwave activation of palladium nanoparticles for enhanced ethanol electrocatalytic oxidation reaction in alkaline medium

    CSIR Research Space (South Africa)

    Rohwer, MB

    2015-02-01

    Full Text Available gave higher electrochemical active surface area (EASA= 67 m(SUP2)g(SUP-1), aggregation/uniformity of dispersion, showed higher amount of the palladium oxides, and showed remarkable electrocatalytic behaviour towards ethanol oxidation reaction...

  14. Culture medium modulates the behaviour of human dental pulp-derived cells: Technical Note

    Directory of Open Access Journals (Sweden)

    S Lopez-Cazaux

    2006-02-01

    Full Text Available In vitro approaches have extensively been developed to study reparative dentinogenesis. While dental pulp is a source of unidentified progenitors able to differentiate into odontoblast-like cells, we investigated the effect of two media; MEM (1.8mM Ca and 1mM Pi and RPMI 1640 (0.8mM Ca and 5mM Pi on the behaviour of human dental pulp cells. Our data indicate that MEM significantly increased cell proliferation and markedly enhanced the proportion of -smooth muscle actin positive cells, which represent a putative source of progenitors able to give rise to odontoblast-like cells. In addition, MEM strongly stimulated alkaline phosphatase activity and was found to induce expression of transcripts encoding dentin sialophosphoprotein, an odontoblastic marker, without affecting that of parathyroid hormone/parathyroid hormone related protein-receptor and osteonectin. In conclusion, these observations demonstrate that not only proliferation but also differentiation into odontoblast-like cells was induced by rich calcium and poor phosphate medium (MEM as compared to RPMI 1640. This study provides important data for the determination of the optimal culture conditions allowing odontoblast-like differentiation in human pulp cell culture.

  15. Medium pH in submerged cultivation modulates differences in the intracellular protein profile of Fusarium oxysporum.

    Science.gov (United States)

    da Rosa-Garzon, Nathália Gonsales; Laure, Hélen Julie; Souza-Motta, Cristina Maria de; Rosa, José César; Cabral, Hamilton

    2017-08-09

    Fusarium oxysporum is a filamentous fungus that damages a wide range of plants and thus causes severe crop losses. In fungal pathogens, the genes and proteins involved in virulence are known to be controlled by environmental pH. Here, we report the influence of culture-medium pH (5, 6, 7, and 8) on the production of degradative enzymes involved in the pathogenesis of F. oxysporum URM 7401 and on the 2D-electrophoresis profile of intracellular proteins in this fungus. F. oxysporum URM 7401 was grown in acidic, neutral, and alkaline culture media in a submerged bioprocess. After 96 hr, the crude extract was processed to enzyme activity assays, while the intracellular proteins were obtained from mycelium and analyzed using 2D electrophoresis and mass spectrometry. We note that the diversity of secreted enzymes was changed quantitatively in different culture-medium pH. Also, the highest accumulated biomass and the intracellular protein profile of F. oxysporum URM 7401 indicate an increase in metabolism in neutral-alkaline conditions. The differential profiles of secreted enzymes and intracellular proteins under the evaluated conditions indicate that the global protein content in F. oxysporum URM 7401 is modulated by extracellular pH.

  16. Population structure of manganese-oxidizing bacteria in stratified soils and properties of manganese oxide aggregates under manganese-complex medium enrichment.

    Directory of Open Access Journals (Sweden)

    Weihong Yang

    Full Text Available Manganese-oxidizing bacteria in the aquatic environment have been comprehensively investigated. However, little information is available about the distribution and biogeochemical significance of these bacteria in terrestrial soil environments. In this study, stratified soils were initially examined to investigate the community structure and diversity of manganese-oxidizing bacteria. Total 344 culturable bacterial isolates from all substrata exhibited Mn(II-oxidizing activities at the range of 1 µM to 240 µM of the equivalent MnO2. The high Mn(II-oxidizing isolates (>50 mM MnO2 were identified as the species of phyla Actinobacteria, Firmicutes and Proteobacteria. Seven novel Mn(II-oxidizing bacterial genera (species, namely, Escherichia, Agromyces, Cellulomonas, Cupriavidus, Microbacterium, Ralstonia, and Variovorax, were revealed via comparative phylogenetic analysis. Moreover, an increase in the diversity of soil bacterial community was observed after the combined enrichment of Mn(II and carbon-rich complex. The phylogenetic classification of the enriched bacteria represented by predominant denaturing gradient gel electrophoresis bands, was apparently similar to culturable Mn(II-oxidizing bacteria. The experiments were further undertaken to investigate the properties of the Mn oxide aggregates formed by the bacterial isolates with high Mn(II-oxidizing activity. Results showed that these bacteria were closely encrusted with their Mn oxides and formed regular microspherical aggregates under prolonged Mn(II and carbon-rich medium enrichment for three weeks. The biotic oxidation of Mn(II to Mn(III/IV by these isolates was confirmed by kinetic examinations. X-ray diffraction assays showed the characteristic peaks of several Mn oxides and rhodochrosite from these aggregates. Leucoberbelin blue tests also verified the Mn(II-oxidizing activity of these aggregates. These results demonstrated that Mn oxides were formed at certain amounts under the

  17. Modulation of Radiation responses by pre-exposure to irradiated Cell conditioned medium.

    LENUS (Irish Health Repository)

    Maguire, Paula

    2007-04-01

    The aim of this study was to investigate whether exposure of HPV-G cells to irradiated cell conditioned medium (ICCM) could induce an adaptive response if the cells were subsequently challenged with a higher ICCM dose. Clonogenic survival and major steps in the cascade leading to apoptosis, such as calcium influx and loss of mitochondrial membrane potential, were examined to determine whether these events could be modified by giving a priming dose of ICCM before the challenge dose. Clonogenic survival data indicated an ICCM-induced adaptive response in HPV-G cells "primed" with 5 mGy or 0.5 Gy ICCM for 24 h and then exposed to 0.5 Gy or 5 Gy ICCM. Reactive oxygen species (ROS) were found to be involved in the bystander-induced cell death. Calcium fluxes varied in magnitude across the exposed cell population, and a significant number of the primed HPV-G cells did not respond to the challenge ICCM dose. No significant loss of mitochondrial membrane potential was observed when HPV-G cells were exposed to 0.5 Gy ICCM for 24 h followed by exposure to 5 Gy ICCM for 6 h. Exposure of HPV-G cells to 5 mGy ICCM for 24 h followed by exposure to 0.5 Gy ICCM for 18 h caused a significant increase in mitochondrial mass and a change in mitochondrial location, events associated with the perpetuation of genomic instability. This study has shown that a priming dose of ICCM has the ability to induce an adaptive response in HPV-G cells subsequently exposed to a challenge dose of ICCM.

  18. Spectrophotometric and potentiometric studies of oxidation of Mo(III) by Mo(VI) in phosphoric acid medium

    International Nuclear Information System (INIS)

    Kumar, Arvind; Verma, G.S.P.

    1975-01-01

    Oxidation of Mo(III) (green) by Mo(VI) in an inert atmosphere and in orthophosphoric acid medium at various acid concentrations is reported. Potentiometric and spectrophotometric data suggest that oxidation of Mo(III) proceeds to Mo(V) through a binuclear species Mo(III) Mo(IV) absorbing at 400 nm. The formation of this species is facilitated at high acid concentrations. It is further found that quantitative conversion of Mo(III) into Mo(V) takes place at fairly high acid concentrations. In high phosphoric acid concentrations, solution of Mo(III) has been found to be oxidized to Mo(VI) by air and hence this can be used as a good oxygen absorber. (author)

  19. Performance and stress analysis of oxide thermoelectric module architecture designed for maximum power output

    DEFF Research Database (Denmark)

    Wijesekara, Waruna; Rosendahl, Lasse; Wu, NingYu

    Oxide thermoelectric materials are promising candidates for energy harvesting from mid to high temperature heat sources. In this work, the oxide thermoelectric materials and the final design of the high temperature thermoelectric module were developed. Also, prototypes of oxide thermoelectric gen...... and simulation results were validated. In addition, the thermal stress and the thermal expansion of the thermoelectric uni-couple were studied in this work....... generator were built for high temperature applications. This paper specifically discusses the thermoelectric module design and the prototype validations of the design. Here p type calcium cobalt oxide and n type aluminum doped ZnO were developed as the oxide thermoelectric materials. Hot side and cold side...

  20. Oxidative stabilization of mixed mayonnaises made with linseed oil and saturated medium-chain triglyceride oil

    NARCIS (Netherlands)

    Raudsepp, P.; Brüggemann, D.A.; Lenferink, Aufrid T.M.; Otto, Cornelis; Andersen, M.L.

    2014-01-01

    Mayonnaises, made with either saturated medium chain triglyceride (MCT) oil or unsaturated purified linseed oil (LSO), were mixed. Raman confocal microspectrometry demonstrated that lipid droplets in mixed mayonnaise remained intact containing either MCT oil or LSO. Peroxide formation during storage

  1. Preparation and characterization of electrocatalysts based on palladium for electro-oxidation of alcohols in alkaline medium

    International Nuclear Information System (INIS)

    Brandalise, Michele

    2012-01-01

    In this study Pd/C, Au/C, PdAu/C, PdAuPt/C, PdAuBi/C and PdAuIr/C electrocatalysts were prepared by the sodium borohydride reduction method for the electrochemical oxidation of methanol, ethanol and ethylene glycol. This methodology consists in mix an alkaline solution of sodium borohydride to a mixture containing water/isopropyl alcohol, metallic precursors and the Vulcan XC 72 carbon support. The electrocatalysts were characterized by energy dispersive X-ray (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry. The electrochemical oxidation of the alcohols was studied by chronoamperometry using a thin porous coating technique. The mechanism of ethanol electro-oxidation was studied by Fourier Transformed Infrared (FTIR) in situ. The most effective electrocatalysts were tested in alkaline single cells directly fed with methanol, ethanol or ethylene glycol. Preliminary studies showed that the most suitable atomic composition for preparing the ternary catalysts is 50:45:05. Electrochemical data in alkaline medium show that the electrocatalysts PdAuPt/C (50:45:05) showed the better activity for methanol electro oxidation, while PdAuIr/C was the most active for ethanol oxidation and PdAuBi/C (50:45:05) was the most effective for ethylene glycol oxidation in alkaline medium. These results show that the addition of gold in the composition of electrocatalysts increases their catalytic activities. The spectroelectrochemical FTIR in situ data permitted to conclude that C-C bond is not broken and the acetate is formed. (author)

  2. Cardiovagal modulation, oxidative stress, and cardiovascular risk factors in prehypertensive subjects: cross-sectional study.

    Science.gov (United States)

    Thiyagarajan, Ramkumar; Pal, Pravati; Pal, Gopal Krushna; Subramanian, Senthil Kumar; Bobby, Zachariah; Das, Ashok Kumar; Trakroo, Madanmohan

    2013-07-01

    Hypertension, one of the modifiable risk factors for cardiovascular disease (CVD), is known to be associated with increased oxidative stress and reduced cardiovagal modulation. Similar to hypertension, prehypertension is associated with increased risk of adverse cardiovascular (CV) events. We planned this study to find the association between prehypertension, cardiovagal modulation, oxidative stress, and associated CV risk factors. We recruited 178 subjects through hypertension screening camps conducted in Puducherry, India. Subjects were grouped into prehypertensive (n = 97) and normotensive (n = 81) groups. They were further subdivided, based on age, as young (20-39 years) and middle-aged (40-60 years) adults. We measured basal physiological parameters, heart rate variability, oxidative stress (thiobarbituric acid reactive substance and total antioxidant capacity (TAC)), and CV risk factors. We found significant increase in oxidative stress in prehypertensive subjects of both age groups but the cardiovagal modulation decreased significantly in young prehypertensive subjects when compared with normotensive subjects. Correlation of TAC with root mean square of the sum of successive R wave to R wave (RR) interval differences (RMSSD), a cardiovagal modulation parameter (r = 0. 437; P risk factors. The correlation between MAP and RMSSD (r = 0.199; P = 0.009) was reduced after adjusting for CV risk factors. Prehypertension in young adults is associated with increased oxidative stress and altered cardiovagal modulation. The risk factors for CVDs in prehypertensive young adults were found to be equivalent to that of middle-aged adults who are in the twilight zone for developing CV dysfunctions.

  3. Ultracompact Silicon-Conductive Oxide Nanocavity Modulator with 0.02 Lambda-Cubic Active Volume.

    Science.gov (United States)

    Li, Erwen; Gao, Qian; Chen, Ray T; Wang, Alan X

    2018-02-14

    Silicon photonic modulators rely on the plasma dispersion effect by free-carrier injection or depletion, which can only induce moderate refractive index perturbation. Therefore, the size and energy efficiency of silicon photonic modulators are ultimately limited as they are also subject to the diffraction limit. Here we report an ultracompact electro-optic modulator with total device footprint of 0.6 × 8 μm 2 by integrating voltage-switched transparent conductive oxide with one-dimensional silicon photonic crystal nanocavity. The active modulation volume is only 0.06 um 3 , which is less than 2% of the lambda-cubic volume. The device operates in the dual mode of cavity resonance and optical absorption by exploiting the refractive index modulation from both the conductive oxide and the silicon waveguide induced by the applied gate voltage. Such a metal-free, hybrid silicon-conductive oxide nanocavity modulator also demonstrates only 0.5 dB extra optical loss, moderate Q-factor above 1000, and high energy efficiency of 46 fJ/bit. The combined results achieved through the holistic design opened a new route for the development of next generation electro-optic modulators that can be used for future on-chip optical interconnects.

  4. Impact of support oxide acidity in Pt-catalyzed HMF hydrogenation in alcoholic medium

    DEFF Research Database (Denmark)

    Al-Shamery, Katharina; Ly, Nhu; Chan-Thaw, Carine E.

    2017-01-01

    Abstract: Silica and three mixed silica oxides (silica–alumina, silica–niobia, and silica–zirconia) with nominally 5 wt% of the added element (Al, Nb and Zr) were prepared and used as supports for dispersing monometallic Pt-nanoparticles. The presence of the second oxide component on the silica s...

  5. Engineering the Saccharomyces cerevisiae β-oxidation pathway to increase medium chain fatty acid production as potential biofuel.

    Science.gov (United States)

    Chen, Liwei; Zhang, Jianhua; Chen, Wei Ning

    2014-01-01

    Fatty acid-derived biofuels and biochemicals can be produced in microbes using β-oxidation pathway engineering. In this study, the β-oxidation pathway of Saccharomyces cerevisiae was engineered to accumulate a higher ratio of medium chain fatty acids (MCFAs) when cells were grown on fatty acid-rich feedstock. For this purpose, the haploid deletion strain Δpox1 was obtained, in which the sole acyl-CoA oxidase encoded by POX1 was deleted. Next, the POX2 gene from Yarrowia lipolytica, which encodes an acyl-CoA oxidase with a preference for long chain acyl-CoAs, was expressed in the Δpox1 strain. The resulting Δpox1 [pox2+] strain exhibited a growth defect because the β-oxidation pathway was blocked in peroxisomes. To unblock the β-oxidation pathway, the gene CROT, which encodes carnitine O-octanoyltransferase, was expressed in the Δpox1 [pox2+] strain to transport the accumulated medium chain acyl-coAs out of the peroxisomes. The obtained Δpox1 [pox2+, crot+] strain grew at a normal rate. The effect of these genetic modifications on fatty acid accumulation and profile was investigated when the strains were grown on oleic acids-containing medium. It was determined that the engineered strains Δpox1 [pox2+] and Δpox1 [pox2+, crot+] had increased fatty acid accumulation and an increased ratio of MCFAs. Compared to the wild-type (WT) strain, the total fatty acid production of the strains Δpox1 [pox2+] and Δpox1 [pox2+, crot+] were increased 29.5% and 15.6%, respectively. The intracellular level of MCFAs in Δpox1 [pox2+] and Δpox1 [pox2+, crot+] increased 2.26- and 1.87-fold compared to the WT strain, respectively. In addition, MCFAs in the culture medium increased 3.29-fold and 3.34-fold compared to the WT strain. These results suggested that fatty acids with an increased MCFAs ratio accumulate in the engineered strains with a modified β-oxidation pathway. Our approach exhibits great potential for transforming low value fatty acid-rich feedstock into high

  6. Hydrogen-rich medium protects mouse embryonic fibroblasts from oxidative stress by activating LKB1-AMPK-FoxO1 signal pathway.

    Science.gov (United States)

    Lee, Jihyun; Yang, Goowon; Kim, Young-Joo; Tran, Quynh Hoa; Choe, Wonchae; Kang, Insug; Kim, Sung Soo; Ha, Joohun

    2017-09-23

    Persistent oxidative stress is recognized as a major cause of many pathological conditions as well as ageing. However, most clinical trials of dietary antioxidants have failed to produce successful outcomes in treating oxidative stress-induced diseases. Molecular hydrogen (H 2 ) has recently received considerable attention as a therapeutic agent owing to its novel antioxidant properties, a selective scavenger of hydroxyl and peroxynitrite radicals. Beyond this, numerous reports support that H 2 can modulate the activity of various cellular signal pathways. However, its effect on AMP-activated protein kinase (AMPK) signal pathway, a central regulator of energy hemostasis, has remained almost elusive. Here, we report that hydrogen-rich medium activated LKB1-AMPK signal pathway without ATP depletion, which in turn induced FoxO1-dependent transcription of manganese superoxide dismutase and catalase in mouse embryonic fibroblasts. Moreover, hydrogen-rich media effectively reduced the level of reactive oxygen species in cells treated with hydrogen peroxide and protected these cells from apoptosis in an AMPK-dependent manner. These results suggest that the LKB1-AMPK-FoxO1 signaling pathway is a critical mediator of the antioxidant properties of H 2 , further supporting the idea that H 2 acts as a signaling molecule to serve various physiological functions. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Modulation of neutrophil oxidative burst via histamine receptors

    Czech Academy of Sciences Publication Activity Database

    Číž, Milan; Lojek, Antonín

    2013-01-01

    Roč. 170, č. 1 (2013), s. 17-22 ISSN 0007-1188 R&D Projects: GA MŠk(CZ) LD11010 Institutional support: RVO:68081707 Keywords : neutrophil * oxidative burst * reactive oxygen species Subject RIV: BO - Biophysics Impact factor: 4.990, year: 2013

  8. Modulation of glucose uptake in adipose tissue by nitric oxide ...

    Indian Academy of Sciences (India)

    Madhu

    Karnieli E, Barzilai A, Rafaeloff R and Armoni M 1986 Distribution of glucose transporters in membrane fractions isolated from human adipose cells; relative to cell size; J. Clin. Invest. 78. 1051–1055. Li J, Hu X, Selvakumar P, Russell R R, Cushman S W, Holman. G D and Young L H 2004 Role of the nitric oxide pathway in.

  9. Transparent conducting oxides for electro-optical plasmonic modulators

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Boltasseva, Alexandra; Lavrinenko, Andrei V.

    2015-01-01

    of themost promising new materials as the active layer or core—namely, transparent conducting oxides. Such modulatorscan be made low-loss, compact, and exhibit high tunabilitywhile offering low cost and compatibility with existingsemiconductor technologies. A detailed analysis of differentconfigurations...

  10. Ag supported on carbon fiber cloth as the catalyst for hydrazine oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Liu, Ran; Ye, Ke; Gao, Yinyi; Zhang, Wenping; Wang, Guiling; Cao, Dianxue

    2015-01-01

    Highlights: • CFC supported microspherical Ag is obtained by square-wave potential method. • Ag/CFC electrode has high catalytic activity toward hydrazine oxidation. • Hydrazine oxidation on the electrode proceeds by a near 4-electron pathway. - Abstract: Silver particles with microspheric structure are directly electrodeposited on carbon fiber cloth (CFC) substrate by square-wave potential electrodeposition method. The electrocatalytic behaviors of the Ag/CFC electrode toward hydrazine oxidation in alkaline solution are examined by cyclic voltammetry and chronoamperometry. An onset oxidation potential of -0.5 V and a peak current density of 30 mA cm −2 are achieved in the solution containing 1.0 mol L −1 KOH and 20.0 mmol L −1 hydrazine. The microspheric structure of the Ag/CFC electrode provides large electroactive surface area, hence, abundant active sites are vacant for hydrazine oxidation. The calculated apparent activation energies at different potentials show that hydrazine electro-oxidation at higher potential has faster kinetics than that at lower potential. In addition, the transfer electron number of hydrazine oxidation reaction on the Ag/CFC electrode is close to four, suggesting hydrazine is almost completely electrooxidized on the electrode and the full use of hydrazine fuel is basically achieved.

  11. Promotion effect of manganese oxide on the electrocatalytic activity of Pt/C for methanol oxidation in acid medium

    Science.gov (United States)

    Abdel Hameed, R. M.; Fetohi, Amani E.; Amin, R. S.; El-Khatib, K. M.

    2015-12-01

    The modification of Pt/C by incorporating metal oxides for electrocatalytic oxidation of methanol has gained major attention because of the efficiency loss during the course of long-time operation. This work describes the preparation of Pt-MnO2/C electrocatalysts through a chemical route using ethylene glycol or a mixture of ethylene glycol and sodium borohydride as a reducing agent. The crystallite structure and particle size of synthesized electrocatalysts are determined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The addition of MnO2 improves the dispersion of Pt nanoparticles. The electrocatalytic activity of Pt-MnO2/C towards methanol oxidation in H2SO4 solution is investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The onset potential value of methanol oxidation peak is negatively shifted by 169 mV when MnO2 is introduced to Pt/C. Moreover, the charge transfer resistance value at Pt-MnO2/C is about 10 times as low as that at Pt/C. Chronoamperometry and chronopotentiometry show that CO tolerance is greatly improved at Pt-MnO2/C. The increased electrocatalytic activity and enhanced ability to clean platinum surface elect manganese oxide as a suitable promoter for the anode performance in direct methanol fuel cells (DMFCs).

  12. Best Frequency for Temperature Modulation of Tin Oxide Gas Sensor for Chemical Vapor Identification

    OpenAIRE

    R Chutia; M Bhuyan

    2014-01-01

    In this paper, we describe a method of optimum temperature modulation of metal oxide semiconductor (MOS) based gas sensor, operated in dynamic temperature measurement for identification of gas. The volatile organic compound (VOC) sample space consists of fourteen laboratory chemicals sampled at various concentration. We have used eleven number of gas sensors, manufactured by Figaro sensors, Japan. The heater of the sensors were modulated with sawtooth heating waveform of different frequency. ...

  13. Thermal-hydraulic investigation of the creep-fatigue specimens in the IFMIF medium flux test module

    Energy Technology Data Exchange (ETDEWEB)

    Gordeev, S.; Heinzel, V.; Schleisiek, K. [Ingenieurbuero Dr.-Ing. W. Hering, Karlsruhe (Germany)

    2004-08-01

    IFMIF (international fusion materials irradiation facility) is a facility under development to irradiate fusion relevant materials. The irradiation volume is divided into three sections, the high-, medium, and low flux test module. The medium flux test module (MFTM) consists of three submodules arranged in series in the direction of the beam. The first submodule at the beam entrance side is housing several creep-fatigue specimens. Direct electrical heating is envisaged to adjust and control the desired irradiation temperature of the specimens. The main problem in designing this submodule is to reach the level of the irradiation temperature with reasonably low temperature differences in the specimens. Preliminary estimates confirmed the suitability of the envisaged design for reaching the desired irradiation temperature but did not deliver the temperature distribution in the specimens. To obtain information on this subject a series of numerical analyses was carried out using the CFD code STAR-CD. To keep the effort in the present early design phase reasonably low, the computer model of the test installation including the initial and boundary conditions were kept as simple as possible. Nevertheless, the results are a useful additional contribution to the further design and layout of the concept. The most important conclusions and recommendation on the concept variants are summarized at the end of the report. (orig.) [German] IFMIF (International Fusion Materials Irradiation Facility) ist eine in der Planung befindliche Einrichtung zur Bestrahlung von Fusionsreaktor-relevanten Materialien. Das Bestrahlungsvo-lumen gliedert sich in drei Bereiche, den Hoch-, Mittel- und Niederflusstestmodul. Das Mittelflusstestmodul (MFTM) besteht aus drei Submodulen, die in Strahlrichtung hinter-einander angeordnet sind. Im ersten Submodul auf der Strahleintrittsseite sind drei Ermue-dungsproben untergebracht. Zur Einstellung und Konstanthaltung der gewuenschten Bestrah

  14. NEW INSIGTHS ON THE KINETICS AND MECHANISM OF THE ELECTROCHEMICAL OXIDATION OF DICLOFENAC IN NEUTRAL AQUEOUS MEDIUM

    International Nuclear Information System (INIS)

    Cid-Cerón, M.M.; Guzmán-Hernández, D.S.; Ramírez-Silva, M.T.; Galano, A.; Romero-Romo, M.; Palomar-Pardavé, M.

    2016-01-01

    Highlights: • DCF electrochemical oxidation was studied from aqueous solution with a CPE. • Both stagnant and forced convection conditions were considered. • We found DCF electrochemical oxidation is a mass transfer-controlled process. • An EC mechanism was found where the electrodic is quasi-reversible. • C reaction provokes the breaking up the DCF through the nitrogen atom. • DCF diffusion coefficient was experimental and theoretically calculated. - Abstract: The diclofenac (DCF) electrochemical oxidation mechanism was studied through: linear voltammetry (LV), chronoamperometry (CA) sampled-current voltammetry (SCV), potentiostatic coulometry (PC) cyclic voltammetry (CV) under stagnant conditions and linear voltammetry under forced convection conditions (FCLV) over a carbon paste electrode (CPE) from an aqueous medium containing 0.1 M phosphate buffer at pH 7. It was found that the DCF electrochemical oxidation involves an EC mechanism, where the electrochemical reaction is carried out through a one electron-exchange while the chemical reaction involves breaking up the DCF through the nitrogen atom, thereby generating the fragments 2,6 dichloroaniline and 2-(2hydroxyprop-2-enyl)phenol. Reverting the potential scan in the cathodic direction at different scan rates and regardless of its rate, after the oxidation peak, it was found that it was possible to reduce only 38% of the DCF oxidized. The spectrophotometric study carried out during different macro-electrolysis periods allowed observing that the current decrease of the oxidation peak coupled to the DCF absorption (at 270 nm), together with the development of a new spectrophotometric absorption maximum (450 nm), all confirm the EC mechanism proposed. With the use of several experimental techniques (CA, LV and FCLV) and theoretical ones using the Stokes–Einstein approach, the DCF diffusion coefficient was determined, this being in average 8.1 × 10 −6 cm 2 s −1 .

  15. Bicarbonate modulates oxidative and functional damage in ischemia-reperfusion.

    Science.gov (United States)

    Queliconi, Bruno B; Marazzi, Thire B M; Vaz, Sandra M; Brookes, Paul S; Nehrke, Keith; Augusto, Ohara; Kowaltowski, Alicia J

    2013-02-01

    The carbon dioxide/bicarbonate (CO(2)/HCO(3)(-)) pair is the main biological pH buffer. However, its influence on biological processes, and in particular redox processes, is still poorly explored. Here we study the effect of CO(2)/HCO(3)(-) on ischemic injury in three distinct models (cardiac HL-1 cells, perfused rat heart, and Caenorhabditis elegans). We found that, although various concentrations of CO(2)/HCO(3)(-) do not affect function under basal conditions, ischemia-reperfusion or similar insults in the presence of higher CO(2)/HCO(3)(-) resulted in greater functional loss associated with higher oxidative damage in all models. Because the effect of CO(2)/HCO(3)(-) was observed in all models tested, we believe this buffer is an important determinant of oxidative damage after ischemia-reperfusion. Copyright © 2012 Elsevier Inc. All rights reserved.

  16. Modulational instability of ultra-low-frequency shear dust Alfvén waves in a plasma medium of positive and negatively charged dust fluids

    International Nuclear Information System (INIS)

    Mamun, A. A.

    2014-01-01

    The propagation of finite amplitude ultra-low-frequency shear dust Alfvén (SDA) waves, and their modulational instability in a magnetized plasma medium of positive and negatively charged dust fluids have been theoretically investigated by using the reductive perturbation method. The derivative nonlinear Schrödinger equation is derived to examine the stability analysis of such SDA waves. It is found that the SDA waves propagating in such an opposite polarity dust plasma medium are modulationally unstable, and that the instability criterion and the growth rate of these unstable SDA waves in such a novel opposite polarity dust plasma medium are found to be significantly different from those in electron–ion or electron–positron plasma media. The implications of the present investigation in different space environments and laboratory devices are briefly discussed.

  17. Kinetic Analysis of the Anodic Carbon Oxidation Mechanism in a Molten Carbonate Medium

    International Nuclear Information System (INIS)

    Allen, Jessica A.; Tulloch, John; Wibberley, Louis; Donne, Scott W.

    2014-01-01

    The oxidation mechanism for carbon in a carbonate melt was modelled using an electrochemical kinetic approach. Through the Butler-Volmer equation for electrode kinetics, a series of expressions was derived assuming each step of the proposed carbon oxidation mechanism is in turn the rate determining step (RDS). Through the derived expressions the transfer coefficient and Tafel slope were calculated for each possible RDS of the proposed mechanism and these were compared with real data collected on carbon based electrodes including graphite and coal. It was established that the RDS of the electrochemical oxidation process is dependent on both the carbon type and the potential region of oxidation. The simplified kinetic analysis suggested that the RDS in the main oxidation region is likely to be the first or second electron transfer on a graphite electrode surface, which occurs following initial adsorption of an oxygen anion to an active carbon site. This is contrary to previous suggestions that adsorption of the second anion to the carbon surface will be rate determining. It was further shown that use of a coal based carbon introduces a change in mechanism with an additional reaction region where a different mechanism is proposed to be operating

  18. Promotion effect of manganese oxide on the electrocatalytic activity of Pt/C for methanol oxidation in acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Abdel Hameed, R.M., E-mail: randa311eg@yahoo.com [Chemistry Department, Faculty of Science, Cairo University, Giza (Egypt); Fetohi, Amani E.; Amin, R.S.; El-Khatib, K.M. [Chemical Engineering Department, National Research Center, Dokki, Giza (Egypt)

    2015-12-30

    Graphical abstract: Physical and electrochemical properties of Pt/C, Pt–MnO{sub 2}/C-1 and Pt–MnO{sub 2}/C-2 electrocatalysts. - Highlights: • Adding MnO{sub 2} to Pt/C improved the dispersion of Pt nanoparticles. • The existence of MnO{sub 2} improved the kinetics of methanol oxidation reaction. • R{sub ct} value of Pt–MnO{sub 2}/C was about 10 times as low as that at Pt/C. • The removal of CO{sub ads} poisoning species was facilitated at Pt–MnO{sub 2}/C. - Abstract: The modification of Pt/C by incorporating metal oxides for electrocatalytic oxidation of methanol has gained major attention because of the efficiency loss during the course of long-time operation. This work describes the preparation of Pt–MnO{sub 2}/C electrocatalysts through a chemical route using ethylene glycol or a mixture of ethylene glycol and sodium borohydride as a reducing agent. The crystallite structure and particle size of synthesized electrocatalysts are determined using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The addition of MnO{sub 2} improves the dispersion of Pt nanoparticles. The electrocatalytic activity of Pt–MnO{sub 2}/C towards methanol oxidation in H{sub 2}SO{sub 4} solution is investigated using cyclic voltammetry and electrochemical impedance spectroscopy. The onset potential value of methanol oxidation peak is negatively shifted by 169 mV when MnO{sub 2} is introduced to Pt/C. Moreover, the charge transfer resistance value at Pt–MnO{sub 2}/C is about 10 times as low as that at Pt/C. Chronoamperometry and chronopotentiometry show that CO tolerance is greatly improved at Pt–MnO{sub 2}/C. The increased electrocatalytic activity and enhanced ability to clean platinum surface elect manganese oxide as a suitable promoter for the anode performance in direct methanol fuel cells (DMFCs).

  19. Electrochemical degradation of the antihypertensive losartan in aqueous medium by electro-oxidation with boron-doped diamond electrode.

    Science.gov (United States)

    Salazar, Claudio; Contreras, Nicole; Mansilla, Héctor D; Yáñez, Jorge; Salazar, Ricardo

    2016-12-05

    In this work the electrochemical oxidation of losartan, an emerging pharmaceutical pollutant, was studied. Electrochemical oxidation was carried out in batch mode, in an open and undivided cell of 100cm(3) using a boron-doped diamond (BDD)/stainless steel system. With Cl(-) medium 56% of mineralization was registered, while with the trials containing SO4(2-) as supporting electrolyte a higher mineralization yield of 67% was reached, even obtaining a total removal of losartan potassium at 80mAcm(-2) and 180min of reaction time at pH 7.0. Higher losartan potassium concentrations enhanced the mineralization degree and the efficiency of the electrochemical oxidation process. During the mineralization up to 4 aromatic intermediates were identified by ultra high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). Moreover, short-linear carboxylic acids, like oxalic, succinic and oxamic were detected and quantified by ion-exclusion HPLC. Finally, the ability of the electrochemical oxidation process to mineralize dissolved commercial tablets containing losartan was achieved, obtaining TOC removal up to 71% under optimized conditions (10mAcm(-2), 0.05M Na2SO4, pH 7.0 and 25°C and 360min of electrolysis). Copyright © 2016 Elsevier B.V. All rights reserved.

  20. The Kinetics and Mechanism for the Oxidation of Nicotinic Acid by Peroxomonosulfate in Acidic Aqueous Medium

    International Nuclear Information System (INIS)

    Agrawal, Anju; Sailani, Riya; Gupta, Beena; Khandelwal, C. L.; Sharma, P. D.

    2012-01-01

    The kinetics of oxidation of nicotinic acid by peroxomonosulfate (PMS) has been studied in acetate buffers. Stoichiometry of the reaction corresponds to the reaction of one mole of the oxidant with a mole of nicotinic acid. N→O product has been confirmed both by UV visible and IR spectroscopy. The reaction is second order viz. first order with respect to each reactant. Activation parameters have also been evaluated. A plausible reaction mechanism is mentioned and the derived kinetic rate law accounts for experimental observations

  1. Modulation of Fibrosis in Systemic Sclerosis by Nitric Oxide and Antioxidants

    Directory of Open Access Journals (Sweden)

    Audrey Dooley

    2012-01-01

    Full Text Available Systemic sclerosis (scleroderma: SSc is a multisystem, connective tissue disease of unknown aetiology characterized by vascular dysfunction, autoimmunity, and enhanced fibroblast activity resulting in fibrosis of the skin, heart, and lungs, and ultimately internal organ failure, and death. One of the most important and early modulators of disease activity is thought to be oxidative stress. Evidence suggests that the free radical nitric oxide (NO, a key mediator of oxidative stress, can profoundly influence the early microvasculopathy, and possibly the ensuing fibrogenic response. Animal models and human studies have also identified dietary antioxidants, such as epigallocatechin-3-gallate (EGCG, to function as a protective system against oxidative stress and fibrosis. Hence, targeting EGCG may prove a possible candidate for therapeutic treatment aimed at reducing both oxidant stress and the fibrotic effects associated with SSc.

  2. Alternating magnetic field energy absorption in the dispersion of iron oxide nanoparticles in a viscous medium

    Czech Academy of Sciences Publication Activity Database

    Smolkova, I.S.; Kazantseva, N.E.; Babayan, V.; Smolka, P.; Parmar, H.; Vilcakova, J.; Schneeweiss, Oldřich; Pizúrová, Naděžda

    2015-01-01

    Roč. 374, JAN (2015), s. 508-515 ISSN 0304-8853 Institutional support: RVO:68081723 Keywords : Iron oxide nanoparticles * Coprecipitation * Magnetic interactions * Specific loss power * Hyperthermia Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.357, year: 2015

  3. Amplitude modulation in infrared metamaterial absorbers based on electro-optically tunable conducting oxides

    Science.gov (United States)

    Zografopoulos, D. C.; Sinatkas, G.; Lotfi, E.; Shahada, L. A.; Swillam, M. A.; Kriezis, E. E.; Beccherelli, R.

    2018-02-01

    A class of electro-optically tunable metamaterial absorbers is designed and theoretically investigated in the infrared regime towards realizing free-space amplitude modulators. The spacer between a subwavelength metallic stripe grating and a back metal reflector is occupied by a bilayer of indium tin oxide (ITO) and hafnium oxide (HfO_2). The application of a bias voltage across the bilayer induces free-carrier accumulation at the HfO_2/ITO interface that locally modulates the ITO permittivity and drastically modifies the optical response of the absorber owing to the induced epsilon-near-zero (ENZ) effect. The carrier distribution and dynamics are solved via the drift-diffusion model, which is coupled with optical wave propagation studies in a common finite-element method platform. Optimized structures are derived that enable the amplitude modulation of the reflected wave with moderate insertion losses, theoretically infinite extinction ratio, sub-picosecond switching times and low operating voltages.

  4. Oxidation Resistance of Medium-Carbon Heat-Resistant Cr-Al Steels in Extreme Conditions

    Directory of Open Access Journals (Sweden)

    Mykhail M. Yamshinskij

    2017-10-01

    Full Text Available Background. From the analysis of exploitation of heat-resistant details of thermal power and metallurgical equipment, it was found that the basic characteristic of metallic materials working under extreme conditions is oxidation resistance. However, the choice of materials for work in the conditions of high temperatures and aggressive environments should be made taking into account not only its oxidation resistance but also the possibility of this material to work long time in the conditions of thermal cycling without being damaged, thus thinking about its heat-resistance. Consequently, it is tremendously important to determine the oxidation resistance of iron-based alloys in extreme conditions depending on the presence of main elements – chrome and aluminium – in their content on the basis of study of formation processes on the item surface of high-quality protective oxides films. Objective. The aim of the paper is to establish the selection rules of heat-resistant iron-based alloys for work in extreme conditions depending on temperatures and aggressive environments and to accumulate some information on their oxidation resistance for the creation of a database and development of methodology how to forecast special properties of alloys. Methods. Models with 10 mm in diameter and 20 mm in length were tested in a tubular stove at the temperature of 1200 and 1250 °C during 100 hours. Oxidation resistance was determined by a weight method. Phase composition and structure were explored by modern X-ray structural and metallographic methods. Results. Processes and mechanisms of formation of oxide scale in the conditions of exploitation of items under the temperature 1250 °C in different aggressive environments are established. The optimum boundaries of concentration of basic chemical elements – chrome and aluminium – in heat-resistant alloys for work in extreme conditions depending on temperatures and environments are determined. A database

  5. Medium chain acylcarnitines dominate the metabolite pattern in humans under moderate intensity exercise and support lipid oxidation.

    Directory of Open Access Journals (Sweden)

    Rainer Lehmann

    Full Text Available BACKGROUND: Exercise is an extreme physiological challenge for skeletal muscle energy metabolism and has notable health benefits. We aimed to identify and characterize metabolites, which are components of the regulatory network mediating the beneficial metabolic adaptation to exercise. METHODOLOGY AND PRINCIPAL FINDINGS: First, we investigated plasma from healthy human subjects who completed two independent running studies under moderate, predominantly aerobic conditions. Samples obtained prior to and immediately after running and then 3 and 24 h into the recovery phase were analyzed by a non-targeted (NT- metabolomics approach applying liquid chromatography-qTOF-mass spectrometry. Under these conditions medium and long chain acylcarnitines were found to be the most discriminant plasma biomarkers of moderately intense exercise. Immediately after a 60 min (at 93% V(IAT or a 120 min run (at 70% V(IAT a pronounced, transient increase dominated by octanoyl-, decanoyl-, and dodecanoyl-carnitine was observed. The release of acylcarnitines as intermediates of partial beta-oxidation was verified in skeletal muscle cell culture experiments by probing (13C-palmitate metabolism. Further investigations in primary human myotubes and mouse muscle tissue revealed that octanoyl-, decanoyl-, and dodecanoyl-carnitine were able to support the oxidation of palmitate, proving more effective than L-carnitine. CONCLUSIONS: Medium chain acylcarnitines were identified and characterized by a functional metabolomics approach as the dominating biomarkers during a moderately intense exercise bout possessing the power to support fat oxidation. This physiological production and efflux of acylcarnitines might exert beneficial biological functions in muscle tissue.

  6. Advances in medium and high temperature solid oxide fuel cell technology

    CERN Document Server

    Salvatore, Aricò

    2017-01-01

    In this book well-known experts highlight cutting-edge research priorities and discuss the state of the art in the field of solid oxide fuel cells giving an update on specific subjects such as protonic conductors, interconnects, electrocatalytic and catalytic processes and modelling approaches. Fundamentals and advances in this field are illustrated to help young researchers address issues in the characterization of materials and in the analysis of processes, not often tackled in scholarly books.

  7. Catalytic oxidation of lignin in the medium of nitrobenzene with vanillin obtaining

    OpenAIRE

    Shimanskaya E.; Shavlukevich G.; Gakipova D.

    2017-01-01

    Lignin, due to its structure, is a very valuable supplier of aromatic aldehydes which find wide application in food, chemical and pharmaceutical industries. One of these substances is vanillin, which is widely used in pharmaceutical chemistry. Derivatives of vanillin have antiseptic and antibacterial properties. Drugs, derived from vanillin, are used to stimulate digestion, to treat cardiovascular diseases. Nitrobenzene is the most selective oxidant of lignin and therefore gives the highest p...

  8. Characterization of Pt-Pd/C Electrocatalyst for Methanol Oxidation in Alkaline Medium

    Directory of Open Access Journals (Sweden)

    S. S. Mahapatra

    2011-01-01

    Full Text Available The Pt-Pd/C electrocatalyst was synthesized on graphite substrate by the electrochemical codeposition technique. The physicochemical characterization of the catalyst was done by SEM, XRD, and EDX. The electrochemical characterization of the Pt-Pd/C catalyst for methanol electro-oxidation was studied over a range of NaOH and methanol concentrations using cyclic voltammetry, quasisteady-state polarization, chronoamperometry, and electrochemical impedance spectroscopy. The activity of methanol oxidation increased with pH due to better OH species coverage on the electrode surface. At methanol concentration (>1.0 M, there is no change in the oxidation peak current density because of excess methanol at the electrode surface and/or depletion of OH− at the electrode surface. The Pt-Pd/C catalyst shows good stability and the low value of Tafel slope and charge transfer resistance. The enhanced electrocatalytic activity of the electrodes is ascribed to the synergistic effect of higher electrochemical surface area, preferred OH− adsorption, and ad-atom contribution on the alloyed surface.

  9. Micellar effect on the kinetics of oxidation of methyl blue by Ce(IV in sulfuric acid medium

    Directory of Open Access Journals (Sweden)

    Mohammed Hassan

    2015-01-01

    Full Text Available The kinetics of oxidation of methyl blue (MB by Ce(IV in aqueous and surfactant media has been carried out to explore the micellar effect on the rate and kinetic parameters of the reaction. The reaction was found to be first order with respect to both oxidant and substrate and fractional order with respect to H+. The active kinetic species of the oxidant was found to be Ce(SO4+2 based on the effect of ionic strength and sulfate ion on the rate of the reaction. The presence of micelles was found to inhibit the reaction and this effect has been explained by the association of one of the reactants with the micelles leaving the other reactant in the bulk solution. The binding constant and first order rate constant in micellar medium has been obtained by the application of pseudo-phase model to the experimental data. Interestingly, the temperature dependence of the reaction reveals that the reaction has negative activation energy in the absence of micelles, which turns to a positive value in the presence of micelles.

  10. Redox properties of human medium-chain acyl-CoA dehydrogenase, modulation by charged active-site amino acid residues.

    Science.gov (United States)

    Mancini-Samuelson, G J; Kieweg, V; Sabaj, K M; Ghisla, S; Stankovich, M T

    1998-10-13

    The modulation of the electron-transfer properties of human medium-chain acyl-CoA dehydrogenase (hwtMCADH) has been studied using wild-type and site-directed mutants by determining their midpoint potentials at various pH values and estimating the involved pKs. The mutants used were E376D, in which the negative charge is retained; E376Q, in which one negative charge (pKa approximately 6. 0) is removed from the active center; E99G, in which a different negative charge (pKa approximately 7.3) also is affected; and E376H (pKa approximately 9.3) in which a positive charge is present. Em for hwtMCADH at pH 7.6 is -0.114 V. Results for the site-directed mutants indicate that loss of a negative charge in the active site causes a +0.033 V potential shift. This is consistent with the assumption that electrostatic interactions (as in the case of flavodoxins) and specific charges are important in the modulation of the electron-transfer properties of this class of dehydrogenases. Specifically, these charge interactions appear to correlate with the positive Em shift observed upon binding of substrate/product couple to MCADH [Lenn, N. D., Stankovich, M. T., and Liu, H. (1990) Biochemistry 29, 3709-3715], which coincides with a pK increase of Glu376-COOH from approximately 6 to 8-9 [Rudik, I., Ghisla, S., and Thorpe, C. (1998) Biochemistry 37, 8437-8445]. From the pH dependence of the midpoint potentials of hwtMCADH two mechanistically important ionizations are estimated. The pKa value of approximately 6.0 is assigned to the catalytic base, Glu376-COOH, in the oxidized enzyme based on comparison with the pH behavior of the E376H mutant, it thus coincides with the pK value recently estimated [Vock, P., Engst, S., Eder, M., and Ghisla, S. (1998) Biochemistry 37, 1848-1860]. The pKa of approximately 7.1 is assigned to Glu376-COOH in reduced hwtMCADH. Comparable values for these pKas for Glu376-COOH in pig kidney MCADH are pKox = 6.5 and pKred = 7.9. The Em measured for K304E-MCADH (a

  11. Supplementing zinc oxide nanoparticles to cryopreservation medium minimizes the freeze-thaw-induced damage to spermatozoa.

    Science.gov (United States)

    Isaac, Ann V; Kumari, Sandhya; Nair, Ramya; Urs, Deepak Raj; Salian, Sujith Raj; Kalthur, Guruprasad; Adiga, Satish Kumar; Manikkath, Jyothsna; Mutalik, Srinivas; Sachdev, Divya; Pasricha, Renu

    2017-12-16

    The sperm DNA integrity post cryopreservation of human semen samples is one of the serious concerns in human infertility treatment. In the present study, the beneficial effects of zinc oxide nanoparticles in preserving the functional ability of spermatozoa was explored. Ejaculates of normozoospermic men cryopreserved along with Zinc oxide nanoparticles (ZnONPs) exhibited non-significantly higher percentage of total and progressive motility in frozen-thawed samples compared to control. The sperm chromatin damage and malondialdehyde (MDA) level was significantly lower in ZnONPs group (P spermatozoa's ability to undergo acrosome reaction was also unaltered. Fluorescence microscopy and High resolution transmission electron microscopy analysis demonstrated that the ZnONPs do not penetrate the membrane of spermatozoa but stay around the spermatozoa. In conclusion, the presence of ZnONPs during cryopreservation appears to be beneficial to the spermatozoa as they withstand freeze-thaw process competently better than control, without any adverse effect shown. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Segmented Thermoelectric Oxide-Based Module for High-Temperature Waste Heat Harvesting

    DEFF Research Database (Denmark)

    Le, Thanh Hung; Van Nong, Ngo; Han, Li

    2015-01-01

    We report a high-performance thermoelectric (TE) oxide-based module using the segmentation of half-Heusler Ti0.3Zr0.35Hf0.35CoSb0.8Sn0.2 and misfit-layered cobaltite Ca3Co4O9+δ as the p-leg and 2% Al-doped ZnO as the n-leg. The maximum output power of a 4-couple segmented module at ΔT=700 K attai...

  13. Cardiovascular and Hepatic Toxicity of Cocaine: Potential Beneficial Effects of Modulators of Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Manuela Graziani

    2016-01-01

    Full Text Available Oxidative stress (OS is thought to play an important role in the pharmacological and toxic effects of various drugs of abuse. Herein we review the literature on the mechanisms responsible for the cardiovascular and hepatic toxicity of cocaine with special focus on OS-related mechanisms. We also review the preclinical and clinical literature concerning the putative therapeutic effects of OS modulators (such as N-acetylcysteine, superoxide dismutase mimetics, nitroxides and nitrones, NADPH oxidase inhibitors, xanthine oxidase inhibitors, and mitochondriotropic antioxidants for the treatment of cocaine toxicity. We conclude that available OS modulators do not appear to have clinical efficacy.

  14. Cardiovascular and Hepatic Toxicity of Cocaine: Potential Beneficial Effects of Modulators of Oxidative Stress

    Science.gov (United States)

    Graziani, Manuela; Antonilli, Letizia; Togna, Anna Rita; Grassi, Maria Caterina; Badiani, Aldo; Saso, Luciano

    2016-01-01

    Oxidative stress (OS) is thought to play an important role in the pharmacological and toxic effects of various drugs of abuse. Herein we review the literature on the mechanisms responsible for the cardiovascular and hepatic toxicity of cocaine with special focus on OS-related mechanisms. We also review the preclinical and clinical literature concerning the putative therapeutic effects of OS modulators (such as N-acetylcysteine, superoxide dismutase mimetics, nitroxides and nitrones, NADPH oxidase inhibitors, xanthine oxidase inhibitors, and mitochondriotropic antioxidants) for the treatment of cocaine toxicity. We conclude that available OS modulators do not appear to have clinical efficacy. PMID:26823954

  15. Supplementation of bovine embryo culture medium with L-arginine improves embryo quality via nitric oxide production.

    Science.gov (United States)

    Santana, Priscila Di Paula Bessa; Silva, Thiago Velasco Guimarães; da Costa, Nathália Nogueira; da Silva, Bruno Barauna; Carter, Timothy Frederick; Cordeiro, Marcela da Silva; da Silva, Bruno José Martins; Santos, Simone do Socorro Damasceno; Herculano, Anderson Manoel; Adona, Paulo Roberto; Ohashi, Otávio Mitio; Miranda, Moysés dos Santos

    2014-10-01

    Nitric oxide (NO) is a cell-signaling molecule that regulates a variety of molecular pathways. We investigated the role of NO during preimplantation embryonic development by blocking its production with an inhibitor or supplementing in vitro bovine embryo cultures with its natural precursor, L-arginine, over different periods. Endpoints evaluated included blastocyst rates, development kinetics, and embryo quality. Supplementation with the NO synthase inhibitor N-Nitro-L-arginine-methyl ester (L-NAME) from Days 1 to 8 of culture decreased blastocyst (P L-arginine decreased blastocyst rates (P L-arginine improved embryo hatching rates (P supplementing the embryo culture medium with L-arginine favors preimplantation development of bovine embryos. © 2014 Wiley Periodicals, Inc.

  16. Lutein and zeaxanthin supplementation reduces photo-oxidative damage and modulates the expression of inflammation-related genes in retinal pigment epithelial cells

    Science.gov (United States)

    Bian, Qingning; Gao, Shasha; Zhou, Jilin; Qin, Jian; Taylor, Allen; Johnson, Elizabeth J.; Tang, Guangwen; Sparrow, Janet R.; Gierhart, Dennis; Shang, Fu

    2012-01-01

    Oxidative damage and inflammation are related to the pathogenesis of age-related macular degeneration (AMD). Epidemiologic studies suggest that insufficient dietary lutein and zeaxanthin intake or lower serum zeaxanthin levels are associated with increased risk for AMD. The objective of this work is to test the protective effects of lutein and zeaxanthin against photo-oxidative damage to retinal pigment epithelial cells (RPE) and oxidation-induced changes in expression of inflammation-related genes. To mimic lipofuscin-mediated photo-oxidation in vivo, we used ARPE-19 cells that accumulated A2E, a lipofuscin fluorophore and photosensitizer, as a model system to investigate the effects of lutein and zeaxanthin supplementation. The data show that supplementation with lutein or zeaxanthin in the medium resulted in accumulation of lutein or zeaxanthin in the RPE cells. The concentrations of lutein and zeaxanthin in the cells were 2–14-fold of that detected in the medium, indicating that ARPE-19 cells actively take up lutein or zeaxanthin. As compared with untreated cells, exposure of A2E-containing RPE to blue light resulted in a 40–60% decrease in proteasome activity, a 50–80% decrease in expression of CFH and MCP-1, and an ~ 20-fold increase in expression of IL-8. The photo-oxidation-induced changes in expression of MCP-1, IL-8 and CFH were similar to those caused by chemical inhibition of the proteasome, suggesting that inactivation of the proteasome is involved in the photo-oxidation-induced alteration in expression of these inflammation-related genes. Incubation of the A2E-containing RPE with lutein or zeaxanthin prior to blue light exposure significantly attenuated the photo-oxidation-induced inactivation of the proteasome and photo-oxidation induced changes in expression of MCP-1, IL-8, and CFH. Together, these data indicate that lutein or zeaxanthin modulates inflammatory responses in cultured RPE in response to photo-oxidation. Protecting the proteasome

  17. Misoprostol modulates the gene expression prostaglandin E2 and oxidative stress markers in myometrial cells.

    Science.gov (United States)

    Konopka, Cristine Kolling; Azzolin, Verônica Farina; Cadoná, Francine Carla; Machado, Alencar Kolinski; Dornelles, Eduardo Bortoluzzi; Barbisan, Fernanda; da Cruz, Ivana Beatrice Mânica

    2016-11-01

    Misoprostol, prostaglandin E1 analogue, used for labour induction. However, one-third of patients who have labour induced with prostaglandins do not reach vaginal delivery. The differential expression of prostaglandin receptors in myometrial cells could account for this differential response. Since delivery physiology also involves modulation of oxidative metabolism that can be potentially affected by pharmacological drugs, in the present investigation the role of misoprostol on expression of prostaglandin receptors, and oxidative markers of myometrial cells was evaluated. Samples of myometrial tissues procured from women with spontaneous (SL) and nonspontaneous (NSL) labours were cultured in vitro and exposed to different concentrations of misoprostol. Gene expression was evaluated by qRT-PCR and oxidative biomarkers were evaluated by spectrophotometric and fluorometric analysis. Cells from SL women presented greater responsiveness to misoprostol, since an upregulation of genes related to increased muscle contraction was observed. Otherwise, cells from NSL women had low responsiveness to misoprostol exposure or even a suppressive effect on the expression of these genes. Oxidative biomarkers that previously have been related to labour physiology were affected by misoprostol treatment: lipoperoxidation and protein carbonylation (PC). However, a decrease in lipoperoxidation was observed only in SL cells treated with low concentrations of misoprostol, whereas a decrease of PC occurred in all samples treated with different misoprostol concentrations. The results suggest a pharmacogenetic effect of misoprostol in labour induction involving differential regulation of EP receptor genes, as well as some minor differential modulation of oxidative metabolism in myometrial cells. Copyright © 2016. Published by Elsevier Inc.

  18. STOSS - A computer module which can be used in Monte-Carlo-calculation for determining the path of a particle in a heterogeneous medium in three dimensions

    International Nuclear Information System (INIS)

    Sdouz, G.

    1980-09-01

    The computer program STOSS determines the path of a particle in a heterogenous medium in three dimensions. The program can be used as a module in Monte-Carlo-calculations. The collision can be transferred from the centre-of-mass system into a fixed cartesian coordinate-system by means of appropriate transformations. Then the path length is determined and the location of the next collision is calculated. The computational details are discussed at some length. (auth.)

  19. Nanotoxic Profiling of Novel Iron Oxide Nanoparticles Functionalized with Perchloric Acid and SiPEG as a Radiographic Contrast Medium

    Directory of Open Access Journals (Sweden)

    Muhamad Idham Mohamed

    2015-01-01

    Full Text Available Emerging syntheses and findings of new metallic nanoparticles (MNPs have become an important aspect in various fields including diagnostic imaging. To date, iodine has been utilized as a radiographic contrast medium. However, the raise concern of iodine threats on iodine-intolerance patient has led to search of new contrast media with lower toxic level. In this animal modeling study, 14 nm iron oxide nanoparticles (IONPs with silane-polyethylene glycol (SiPEG and perchloric acid have been assessed for toxicity level as compared to conventional iodine. The nanotoxicity of IONPs was evaluated in liver biochemistry, reactive oxygen species production (ROS, lipid peroxidation mechanism, and ultrastructural evaluation using transmission electron microscope (TEM. The hematological analysis and liver function test (LFT revealed that most of the liver enzymes were significantly higher in iodine-administered group as compared to those in normal and IONPs groups P<0.05. ROS production assay and lipid peroxidation indicator, malondialdehyde (MDA, also showed significant reductions in comparison with iodine group P<0.05. TEM evaluation yielded the aberration of nucleus structure of iodine-administered group as compared to those in control and IONPs groups. This study has demonstrated the less toxic properties of IONPs and it may postulate that IONPs are safe to be applied as radiographic contrast medium.

  20. Ni/Pd-Decorated Carbon NFs as an Efficient Electrocatalyst for Methanol Oxidation in Alkaline Medium

    Science.gov (United States)

    Mohamed, Ibrahim M. A.; Khalil, Khalil Abdelrazek; Mousa, Hamouda M.; Barakat, Nasser A. M.

    2017-01-01

    In this study, Ni/Pd-decorated carbon nanofibers (NFs) were fabricated as an electrocatalyst for methanol oxidation. These NFs were synthesized based on carbonization of poly(vinyl alcohol), which has high carbon content compared to many polymers used to prepare carbon NFs. Typically, calcination of an electrospun mat composed of nickel acetate, palladium acetate, and poly(vinyl alcohol) can produce Ni/Pd-doped carbon NFs. The introduced NFs were characterized by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution transmission electron microscopy, line TEM energy dispersive x-ray spectrometry, field emission scanning electron microscopy, and x-ray powder diffraction. These physicochemical characterizations are acceptable tools to investigate the crystallinity and chemistry of the fabricated Ni/Pd-carbon NFs. Accordingly, the prepared NFs were tested to enhance the economic and catalytic behavior of methanol electrooxidation. Experimentally, the obtained onset potential was small compared to many reported materials; 0.32 V (versus Ag/AgCl as a reference electrode). At the same time, the current density changed from 5.08 mA/cm2 in free methanol at 0.6 V to 12.68 mA/cm2 in 0.1 mol/L methanol, which can be attributed to the MeOH oxidation. Compared to nanoparticles, the NFs have a distinct effect on the electrocatalytic performance of material due to the effect of the one-dimensional structure, which facilitates the electron transfer. Overall, the presented work opens a new way for non-precious one-dimensional nanostructured catalysts for direct methanol fuel cell technology.

  1. Optical modulation spectroscopy: a study of the self-reaction of benzophenone oxide

    Energy Technology Data Exchange (ETDEWEB)

    Girard, M.; Griller, D.

    1986-12-18

    The bimolecular self-reaction of benzophenone oxide was investigated by optical modulation spectroscopy and by product studies. The transient decayed to give benzophenone and oxygen and the rate constants for its disappearance, 2k, are described by the expression log (2k) = (9.1 +/- 0.2) - (1.8 +/- 0.3)/theta where theta = 2.30RT kcal mol/sup -1/. The significance of these parameters is discussed in terms of the orientational requirements for self-reaction. Benzophenone oxide was found to react with octanal with a rate constant 2.0 x 10/sup 4/ M/sup -1/ s/sup -1/.

  2. Pre-exposure to nitric oxide modulates the effect of ozone on oxidative defenses and volatile emissions in lima bean

    International Nuclear Information System (INIS)

    Souza, Silvia R.; Blande, James D.; Holopainen, Jarmo K.

    2013-01-01

    The roles that ozone and nitric oxide (NO), the chief O 3 precursor, play in the antioxidative balance and inducible volatile emissions of lima bean were assessed. Exposure to O 3 inhibited APX, CAT, and GR, decreased GSH content and induced emissions of (E)-β-ocimene, limonene, 1,8-cineole, linalool, (E)-4,8-dimethyl-1,3,7-nonatriene (E)-DMNT, 2-butanone and nonanal. O 3 did not induce emissions of (E)-β-caryophyllene and appeared to reduce the antioxidative capacity of plants to a greater extent than NO and NO followed by O 3 (NO/O 3 ) treatments. There were significant differences in emissions of (E)-β-ocimene and linalool between NO/O 3 treated plants and controls, but no differences in antioxidant concentrations. A model to explain the relationships between the ascorbate–glutathione cycle and O 3 and NO inducible volatiles was proposed. Our findings suggest that prior exposure to NO modulates the oxidative effect of ozone by the process of cross-tolerance, which might regulate the antioxidative system and induction of volatile organic compounds. -- Highlights: •NO and O 3 disturb antioxidant defenses and cause lipid peroxidation in lima bean plants. •Exposure to NO before exposure to O 3 does not alter the antioxidant defenses and malondialdehyde levels. •The total sum of induced volatiles is reduced in plants that are exposed to NO and then O 3 . •The antioxidant system and induced VOC emission were balanced by pre-exposure to NO before O 3 . -- Capsule: Nitric oxide modulates the ozone-induced oxidative stress in lima bean by cross-tolerance effect

  3. Simvastatin Attenuates Contrast-Induced Nephropathy through Modulation of Oxidative Stress, Proinflammatory Myeloperoxidase, and Nitric Oxide

    Directory of Open Access Journals (Sweden)

    Ketab E. Al-Otaibi

    2012-01-01

    Full Text Available Contrast media- (CM- induced nephropathy is a serious complication of radiodiagnostic procedures. Available data suggests that the development of prophylaxis strategies is limited by poor understanding of pathophysiology of CM-induced nephropathy. Present study was designed to determine the role of oxidative stress, myeloperoxidase, and nitric oxide in the pathogenesis of iohexol model of nephropathy and its modification with simvastatin (SSTN. Adult Sprague Dawley rats were divided into seven groups. After 24 h of water deprivation, all the rats except in control and SSTN-only groups were injected (10 ml/kg with 25% glycerol. After 30 min, SSTN (15, 30, and 60 mg/kg was administered orally, daily for 4 days. Twenty-four hours after the glycerol injection, iohexol was infused (8 ml/kg through femoral vein over a period of 2 min. All the animals were sacrificed on day 5 and blood and kidneys were collected for biochemical and histological studies. The results showed that SSTN dose dependently attenuated CM-induced rise of creatinine, urea, and structural abnormalities suggesting its nephroprotective effect. A significant increase in oxidative stress (increased lipid hydroperoxides and reduced glutathione levels and myeloperoxidase (MPO and decreased nitric oxide in CM group were reversed by SSTN. These findings support the use of SSTN to combat CM-induced nephrotoxicity.

  4. Scale-Up Design Analysis and Modelling of Cobalt Oxide Silica Membrane Module for Hydrogen Processing

    OpenAIRE

    Guozhao Ji; Guoxiong Wang; Kamel Hooman; Suresh K. Bhatia; João C. Diniz da Costa

    2013-01-01

    This work shows the application of a validated mathematical model for gas permeation at high temperatures focusing on demonstrated scale-up design for H2 processing. The model considered the driving force variation with spatial coordinates and the mass transfer across the molecular sieve cobalt oxide silica membrane to predict the separation performance. The model was used to study the process of H2 separation at 500 °C in single and multi-tube membrane modules. Parameters of interest include...

  5. l-Arginine Availability Modulates Local Nitric Oxide Production and Parasite Killing in Experimental Trypanosomiasis

    OpenAIRE

    Gobert, Alain P.; Daulouede, Sylvie; Lepoivre, Michel; Boucher, Jean Luc; Bouteille, Bernard; Buguet, Alain; Cespuglio, Raymond; Veyret, Bernard; Vincendeau, Philippe

    2000-01-01

    Nitric oxide (NO) is an important effector molecule of the immune system in eliminating numerous pathogens. Peritoneal macrophages from Trypanosoma brucei brucei-infected mice express type II NO synthase (NOS-II), produce NO, and kill parasites in the presence of l-arginine in vitro. Nevertheless, parasites proliferate in the vicinity of these macrophages in vivo. The present study shows that l-arginine availability modulates NO production. Trypanosomes use l-arginine for polyamine synthesis,...

  6. Disrupted fat distribution and composition due to medium-chain triglycerides in mice with a β-oxidation defect.

    Science.gov (United States)

    Tucci, Sara; Flögel, Ulrich; Sturm, Marga; Borsch, Elena; Spiekerkoetter, Ute

    2011-08-01

    Because of the enhanced recognition of inherited long-chain fatty acid oxidation disorders by worldwide newborn screening programs, an increasing number of asymptomatic patients receive medium-chain triglyceride (MCT) supplements to prevent the development of cardiomyopathy and myopathy. MCT supplementation has been recognized as a safe dietary intervention, but long-term observations into later adulthood are still not available. We investigated the consequences of a prolonged MCT diet on abdominal fat distribution and composition and on liver fat. Mice with very-long-chain acyl-coenzyme A dehydrogenase deficiency (VLCAD(-/-)) were supplemented for 1 y with a diet in which MCTs replaced long-chain triglycerides without increasing the total fat content. The dietary effects on abdominal fat accumulation and composition were analyzed by in vivo (1)H- and (13)C-magnetic resonance spectroscopy (9.4 Tesla). After 1 y of MCT supplementation, VLCAD(-/-) mice accumulated massive visceral fat and had a dramatic increase in the concentration of serum free fatty acids. Furthermore, we observed a profound shift in body triglyceride composition, ie, concentrations of physiologically important polyunsaturated fatty acids dramatically decreased. (1)H-Magnetic resonance spectroscopy analysis and histologic evaluation of the liver also showed pronounced fat accumulation and marked oxidative stress. Although the MCT-supplemented diet has been reported to prevent the development of cardiomyopathy and skeletal myopathy in fatty acid oxidation disorders, our data show that long-term MCT supplementation results in a severe clinical phenotype similar to that of nonalcoholic steatohepatitis and the metabolic syndrome.

  7. Cardiovascular Mitochondrial Dysfunction Induced by Cocaine: Biomarkers and Possible Beneficial Effects of Modulators of Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Manuela Graziani

    2017-01-01

    Full Text Available Cocaine abuse has long been known to cause morbidity and mortality due to its cardiovascular toxic effects. The pathogenesis of the cardiovascular toxicity of cocaine use has been largely reviewed, and the most recent data indicate a fundamental role of oxidative stress in cocaine-induced cardiovascular toxicity, indicating that mitochondrial dysfunction is involved in the mechanisms of oxidative stress. The comprehension of the mechanisms involving mitochondrial dysfunction could help in selecting the most appropriate mitochondria injury biological marker, such as superoxide dismutase-2 activity and glutathionylated hemoglobin. The potential use of modulators of oxidative stress (mitoubiquinone, the short-chain quinone idebenone, and allopurinol in the treatment of cocaine cardiotoxic effects is also suggested to promote further investigations on these potential mitochondria-targeted antioxidant strategies.

  8. Modulation of Hypercholesterolemia-Induced Oxidative/Nitrative Stress in the Heart

    Science.gov (United States)

    Sárközy, Márta; Pipicz, Márton; Dux, László; Csont, Tamás

    2016-01-01

    Hypercholesterolemia is a frequent metabolic disorder associated with increased risk for cardiovascular morbidity and mortality. In addition to its well-known proatherogenic effect, hypercholesterolemia may exert direct effects on the myocardium resulting in contractile dysfunction, aggravated ischemia/reperfusion injury, and diminished stress adaptation. Both preclinical and clinical studies suggested that elevated oxidative and/or nitrative stress plays a key role in cardiac complications induced by hypercholesterolemia. Therefore, modulation of hypercholesterolemia-induced myocardial oxidative/nitrative stress is a feasible approach to prevent or treat deleterious cardiac consequences. In this review, we discuss the effects of various pharmaceuticals, nutraceuticals, some novel potential pharmacological approaches, and physical exercise on hypercholesterolemia-induced oxidative/nitrative stress and subsequent cardiac dysfunction as well as impaired ischemic stress adaptation of the heart in hypercholesterolemia. PMID:26788247

  9. Direct reduction of uranium oxide(U3O8) by Li metal and U-metal(Fe, Ni) alloy formation in molten LiCl medium

    International Nuclear Information System (INIS)

    Cho, Young Hwan; Kim, Tack Jin; Choi, In Kyu; Kim, Won Ho; Jee, Kwang Yong

    2004-01-01

    Molten salt based electrochemical processes are proposed as a promising method for the future nuclear programs and more specifically for spent fuel processing. The lithium reduction has been introduced to convert actinide oxides into corresponding actinide metal by using lithium metal as a reductant in molten LiCl medium. We have applied similar lab-scale experiments to reduce uranium oxide in an effort to gain additional information on rates and mechanisms

  10. Chronic epigallocatechin-3-gallate ameliorates learning and memory deficits in diabetic rats via modulation of nitric oxide and oxidative stress.

    Science.gov (United States)

    Baluchnejadmojarad, Tourandokht; Roghani, Mehrdad

    2011-10-31

    Due to anti-diabetic and antioxidant activity of green tea epigallocatechin gallate (EGCG) and the existence of evidence for its beneficial effect on cognition and memory, this research study was conducted to evaluate, for the first time, the efficacy of chronic EGCG on alleviation of learning and memory deficits in streptozotocin (STZ)-diabetic rats. Male Wistar rats were divided into control, diabetic, EGCG-treated-control and -diabetic groups. EGCG was administered at a dose of 20 and 40 mg/kg/day for 7 weeks. Learning and memory was evaluated using Y maze, passive avoidance, and radial 8-arm maze (RAM) tests. Oxidative stress markers and involvement of nitric oxide system were also evaluated. Alternation score of the diabetic rats in Y maze was lower than that of control and a significant impairment was observed in retention and recall in passive avoidance test (pRAM task and EGCG (40 mg/kg) significantly ameliorated these changes (pmemory respectively. Meanwhile, increased levels of malondialdehyde (MDA) and nitrite in diabetic rats significantly reduced due to EGCG treatment (pmemory deficits in STZ-diabetic rats through attenuation of oxidative stress and modulation of NO. Copyright © 2011 Elsevier B.V. All rights reserved.

  11. Mechanical Design of the Radio-Isotope Source Driver Module for an Initial Prototype of Medium Dose Rate Brachytherapy

    International Nuclear Information System (INIS)

    Ari Satmoko; Tri Harjanto; Hendra Prasetia

    2012-01-01

    High dose rate brachytherapy equipment for therapy against cervical cancer is developed by empowering local products. An Iridium-192 with 5 Curies of energy is used. The source is wrapped in a capsule and combined with a wire diameter of 1 mm and length 1800 mm. The therapy is carried out by inserting the radiation source into the patient's body through an applicator. The system for loading-unloading the isotope source is divided into three modules: the source driver module, the source container modules, and channel distributor module. In this paper, the discussion is focused on engineering activities of the first module that serves to drive forward and backward position of the Iridium-192 isotope sources. The activity begins with the development of preliminary design sketches that produces drawings of mechanical components required. Furthermore, the calculations are carried out in order to establish the main component specifications. From this stage, a stepper motor type M66-A50K-G10 as a mechanical driver is chosen. The next stage is developing the detailed design and producing detailed drawings for all components. The fabrication of each component refers to the detailed design drawings. All components are assembled completely into the source driver module. Test also shows that the module works manually well. By rotating the manual handle in both directions, the tip of the wire moves alternately in forward and backward directions. (author)

  12. Experimental evidence for protein oxidative damage and altered antioxidant defense in patients with medium-chain acyl-CoA dehydrogenase deficiency

    NARCIS (Netherlands)

    Derks, Terry G J; Touw, Catharina M L; Ribas, Graziela S; Biancini, Giovana B; Vanzin, Camila S; Negretto, Giovanna; Mescka, Caroline P; Reijngoud, Dirk Jan; Smit, G Peter A; Wajner, Moacir; Vargas, Carmen R

    The objective of this study was to test whether macromolecule oxidative damage and altered enzymatic antioxidative defenses occur in patients with medium-chain acyl coenzyme A dehydrogenase (MCAD) deficiency. We performed a cross-sectional observational study of in vivo parameters of lipid and

  13. Fast microwave-assisted solvothermal synthesis of metal nanoparticles (Pd, Ni, Sn) supported on sulfonated MWCNTs: Pd-based bimetallic catalysts for ethanol oxidation in alkaline medium

    CSIR Research Space (South Africa)

    Ramulifho, T

    2012-01-01

    Full Text Available -MWCNT-Pd and its "mixed" bimetallic electrocatalysts (i.e., SF-MWCNT-PdSn mix and SF-MWCNT-PdNi) towards ethanol oxidation in alkaline medium was investigated. The result shows that the mixed Pd-based catalysts (obtained by simple ultrasonic...

  14. Oxidative stress and sodium methyldithiocarbamate-induced modulation of the macrophage response to lipopolysaccharide in vivo.

    Science.gov (United States)

    Pruett, Stephen B; Cheng, Bing; Fan, Ruping; Tan, Wei; Sebastian, Thomas

    2009-06-01

    Sodium methyldithiocarbamate (SMD) is the third most abundantly used conventional pesticide in the United States, and hundreds of thousands of persons are exposed to this compound or its major breakdown product, methylisothiocyanate, at levels greater than recommended by the Environmental Protection Agency. A previous study suggests three mechanisms of action involved to some degree in the inhibition of inflammation and decreased resistance to infection caused by exposure of mice to the compound. One of these mechanisms is oxidative stress. The purpose of the present study was to confirm that this mechanism is involved in the effects of SMD on cytokine production by peritoneal macrophages and to further characterize its role in altered cytokine production. Results indicated that SMD significantly decreased the intracellular concentration of reduced glutathione (GSH), suggesting oxidative stress. This was further indicated by the upregulation of genes involved in the "response to oxidative stress" as determined by microarray analysis. These effects were associated with the inhibition of lipopolysaccharide (LPS)-induced production of several proinflammatory cytokines. Experimental depletion of GSH with buthionine sulfoximine (BSO) partially prevented the decrease in LPS-induced interleukin (IL)-6 production caused by SMD and completely prevented the decrease in IL-12. In contrast, BSO plus SMD substantially enhanced the production of IL-10. These results along with results from a previous study are consistent with the hypothesis that SMD causes oxidative stress, which contributes to modulation of cytokine production. However, oxidative stress alone cannot explain the increased IL-10 production caused by SMD.

  15. Generator module architecture for a large solid oxide fuel cell power plant

    Science.gov (United States)

    Gillett, James E.; Zafred, Paolo R.; Riggle, Matthew W.; Litzinger, Kevin P.

    2013-06-11

    A solid oxide fuel cell module contains a plurality of integral bundle assemblies, the module containing a top portion with an inlet fuel plenum and a bottom portion receiving air inlet feed and containing a base support, the base supports dense, ceramic exhaust manifolds which are below and connect to air feed tubes located in a recuperator zone, the air feed tubes passing into the center of inverted, tubular, elongated, hollow electrically connected solid oxide fuel cells having an open end above a combustion zone into which the air feed tubes pass and a closed end near the inlet fuel plenum, where the fuel cells comprise a fuel cell stack bundle all surrounded within an outer module enclosure having top power leads to provide electrical output from the stack bundle, where the fuel cells operate in the fuel cell mode and where the base support and bottom ceramic air exhaust manifolds carry from 85% to all 100% of the weight of the stack, and each bundle assembly has its own control for vertical and horizontal thermal expansion control.

  16. Anti-oxidant modulation in response to gamma radiation induced oxidative stress in developing seedlings of Psoralea corylifolia L

    International Nuclear Information System (INIS)

    Jan, Sumira; Parween, Talat; Siddiqi, T.O.; Mahmooduzzafar

    2012-01-01

    The seeds of Psoralea corylifolia L., an important medicinal herb in Indian and Chinese Pharmacopeia were exposed to gamma rays (2.5, 5, 10, 15 and 20 kGy) from Co 60 source at dose rate of 1.65 kGy h −1 . Enzymatic and non-enzymatic anti-oxidant responses were verified according to the developmental stages and gamma dose applied. Plants grown from seeds exposed to higher gamma doses exhibit higher activity of the antioxidants such as [Ascorbate peroxidase (APX, 1.11.1.1), superoxide dismutase (SOD, 1.15.1.1), glutathione reductase (GR, 1.6.4.2) and MDA content till flowering and declined thereafter. In contrast, CAT (1.11.1.6) activity declined in dose and age dependent manner. The correlation of gamma dose applied and oxidative stress was inferred from the increased enzymes activities and depression in total glutathione pool in seedlings developed from irradiated seeds. Nevertheless, the maintenance of high anti-oxidant capacity, psoralen accumulation seems to be an important strategy during acclimation of P. corylifolia to gamma radiation stress. Pronounced accumulation of psoralen following 15 and 20 kGy at post-flowering stage where oxidative stress is triggered modulates lipid peroxidation and proline accumulation. Further, in psoralen producing plants an increase in psoralen content can be used as a biomarker which specifies plant is under stress. - Highlights: ► This manuscript points for the first time over expression of antioxidant enzymes to variable doses of gamma rays with corresponding increase in psoralen content in Psoralea corylifolia L. ► Decline in lipid peroxidation and proline accumulation was concomitant with psoralen increment describing the potential of Psoralen as antioxidant. ► Survival of plants following higher dosage of gamma-radiation (15 and 20 kGy) describes the radio resistivity of Psorelea seeds.

  17. Nigella sativa fixed and essential oil modulates glutathione redox enzymes in potassium bromate induced oxidative stress.

    Science.gov (United States)

    Sultan, Muhammad Tauseef; Butt, Masood Sadiq; Karim, Roselina; Ahmed, Waqas; Kaka, Ubedullah; Ahmad, Shakeel; Dewanjee, Saikat; Jaafar, Hawa Z E; Zia-Ul-Haq, M

    2015-09-18

    Nigella sativa is an important component of several traditional herbal preparations in various countries. It finds its applications in improving overall health and boosting immunity. The current study evaluated the role of fixed and essential oil of Nigella sativa against potassium bromate induced oxidative stress with special reference to modulation of glutathione redox enzymes and myeloperoxidase. Animals; 30 rats (Sprague Dawley) were divided in three groups and oxidative stress was induced using mild dose of potassium bromate. The groups were on their respective diets (iso-caloric diets for a period of 56 days) i.e. control and two experimental diets containing N. sativa fixed (4%) and essential (0.3%) oils. The activities of enzymes involved in glutathione redox system and myeloperoxidase (MPO) were analyzed. The experimental diets modulated the activities of enzymes i.e. glutathione-S-transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx) positively. Indices of antioxidant status like tocopherols and glutathione were in linear relationship with that of GPx, GR and GST (PNigella sativa fixed and essential oil are effective in improving the antioxidant indices against potassium bromate induced oxidative stress.

  18. Order of Activity of Nitrogen, Iron Oxide, and FeNx Complexes towards Oxygen Reduction in Alkaline Medium.

    Science.gov (United States)

    Zhu, Yansong; Zhang, Bingsen; Wang, Da-Wei; Su, Dang Sheng

    2015-12-07

    In alkaline medium, it seems that both metal-free and iron-containing carbon-based catalysts, such as nitrogen-doped nanocarbon materials, FeOx -doped carbon, and Fe/N/C catalysts, are active for the oxygen reduction reaction (ORR). However, the order of activity of these different active compositions has not been clearly determined. Herein, we synthesized nitrogen-doped carbon black (NCB), Fe3 O4 /CB, Fe3 O4 /NCB, and FeN4 /CB. Through the systematic study of the ORR catalytic activity of these four catalysts in alkaline solution, we confirmed the difference in the catalytic activity and catalytic mechanism for nitrogen, iron oxides, and Fe-N complexes, respectively. In metal-free NCB, nitrogen can improve the ORR catalytic activity with a four-electron pathway. Fe3 O4 /CB catalyst did not exhibit improved activity over that of NCB owing to the poor conductivity and spinel structure of Fe3 O4 . However, FeN4 coordination compounds as the active sites showed excellent ORR catalytic activity. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Tryptophan oxidation catabolite, N-formylkynurenine, in photo degraded cell culture medium results in reduced cell culture performance.

    Science.gov (United States)

    McElearney, Kyle; Ali, Amr; Gilbert, Alan; Kshirsagar, Rashmi; Zang, Li

    2016-01-01

    Chemically defined media have been widely used in the biopharmaceutical industry to enhance cell culture productivities and ensure process robustness. These media, which are quite complex, often contain a mixture of many components such as vitamins, amino acids, metals and other chemicals. Some of these components are known to be sensitive to various stress factors including photodegradation. Previous work has shown that small changes in impurity concentrations induced by these potential stresses can have a large impact on the cell culture process including growth and product quality attributes. Furthermore, it has been shown to be difficult to detect these modifications analytically due to the complexity of the cell culture media and the trace level of the degradant products. Here, we describe work performed to identify the specific chemical(s) in photodegraded medium that affect cell culture performance. First, we developed a model system capable of detecting changes in cell culture performance. Second, we used these data and applied an LC-MS analytical technique to characterize the cell culture media and identify degradant products which affect cell culture performance. Riboflavin limitation and N-formylkynurenine (NFK), a tryptophan oxidation catabolite, were identified as chemicals which results in a reduction in cell culture performance. © 2015 American Institute of Chemical Engineers.

  20. Kinetics and Mechanism of Micellar Catalyzed Oxidation of Dextrose by N-Bromosuccinimide in H2SO4 Medium

    Directory of Open Access Journals (Sweden)

    Minu Singh

    2014-01-01

    Full Text Available Kinetics and mechanism of micellar catalyzed N-bromosuccinimide oxidation of dextrose in H2SO4 medium was investigated under pseudo-first-order condition temperature of 40°C. The results of the reactions studied over a wide range of experimental conditions show that NBS shows a first order dependence, fractional order, on dextrose and negative fractional order dependence on sulfuric acid. The determined stoichiometric ratio was 1 : 1 (dextrose : N-bromosuccinimide. The variation of Hg(OAC2 and succinimide (reaction product has insignificant effect on reaction rate. Effects of surfactants, added acrylonitrile, added salts, and solvent composition variation have been studied. The Arrhenius activation energy and other thermodynamic activation parameters are evaluated. The rate law has been derived on the basis of obtained data. A plausible mechanism has been proposed from the results of kinetic studies, reaction stoichiometry, and product analysis. The role of anionic and nonionic micelle was best explained by the Berezin’s model.

  1. Chemical Characterization and Oxidative Stability of Medium- and Long-Chain Fatty Acid Profiles in Tree-Borne Seed Oils

    Directory of Open Access Journals (Sweden)

    Da-Som Kim

    2018-01-01

    Full Text Available This study was undertaken to evaluate chemical characteristics and oxidative stability of tree-borne seed oils. A total of 15 different fatty acids were identified in six tree-borne seed oils, which included seven types of saturated fatty acids, four types of monounsaturated fatty acids, and four types of polyunsaturated fatty acids. Japanese camphor tree (JCT had a high content of medium-chain fatty acids (97.94 ± 0.04%, in which fatty acid composition was distinct from those of the other five plant seed oils. Overall, contents of tocopherols, a type of fat-soluble vitamin, ranged between 3.82 ± 0.04 mg/100 g and 101.98 ± 1.34 mg/100 g, respectively. Phytosterol contents ranged from 117.77 ± 1.32 mg/100 g to 479.45 ± 4.27 mg/100 g, respectively. Of all tree-borne seed oils, β-sitosterol was the phytosterol at the highest concentration. Contents of unsaponifiables were between 0.13 ± 0.08 and 2.01 ± 0.02, and values of acid, peroxide, and p-anisidine were between 0.79 ± 0.01 and 38.94 ± 0.24 mg KOH/g, 3.53 ± 0.21 and 127.67 ± 1.79 meq/kg, and 2.07 ± 0.51 and 9.67 ± 0.25, respectively. Oxidative stability of tree-borne seed oils was assessed through measurement of oxidation-induction periods. These results should serve as a foundation to identify the potential of tree-borne seed oils in industrial application as well as in providing fundamental data.

  2. Redox Properties of Human Medium-Chain Acyl-CoA Dehydrogenase, Modulation by Charged Active-Site Amino Acid Residues

    OpenAIRE

    Mancini-Samuelson, Gina J.; Kieweg, Volker; Sabaj, Kim Marie; Ghisla, Sandro; Stankovich, Marian T.

    1998-01-01

    The modulation of the electron-transfer properties of human medium-chain acyl-CoA dehydrogenase (hwtMCADH) has been studied using wild-type and site-directed mutants by determining their midpoint potentials at various pH values and estimating the involved pKs. The mutants used were E376D, in which the negative charge is retained; E376Q, in which one negative charge (pKa ≈ 6.0) is removed from the active center; E99G, in which a different negative charge (pKa ≈ 7.3) also is affected; and E376H...

  3. Modulating Crystallinity of Graphitic Carbon Nitride for Photocatalytic Oxidation of Alcohols.

    Science.gov (United States)

    Zhou, Min; Yang, Pengju; Yuan, Rusheng; Asiri, Abdullah M; Wakeel, Muhammad; Wang, Xinchen

    2017-11-23

    Exploiting efficient photocatalysts with strengthened structure for solar-driven alcohol oxidation is of great significance. The photocatalytic performance of graphitic carbon nitrides can be considerably promoted by modulating its crystallinity. Results confirmed that a high crystallinity accelerates the separation and transfer of photogenerated charge carriers, thus providing more free charges for photoredox reactions. More importantly, the high crystallinity facilitated the adsorption of benzyl alcohol and desorption of benzaldehyde and simultaneously lowered the energy barrier for O 2 activation. As a result, the crystalline carbon nitride exhibited a roughly twelvefold promotion with respect to the normal carbon nitride. The remarkable enhancement of activity can be attributed to the synergistic effects of increased electron-hole separation and increased surface reaction kinetics. These findings will open up new opportunities to modulate the structure of polymers for a wide variety of organic reactions. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Endothelial nitric oxide synthase polymorphisms and adaptation of parasympathetic modulation to exercise training.

    Science.gov (United States)

    Silva, Bruno M; Neves, Fabricia J; Negrão, Marcelo V; Alves, Cleber R; Dias, Rodrigo G; Alves, Guilherme B; Pereira, Alexandre C; Rondon, Maria U; Krieger, José E; Negrão, Carlos E; DA Nóbrega, Antonio Claudio Lucas

    2011-09-01

    There is a large interindividual variation in the parasympathetic adaptation induced by aerobic exercise training, which may be partially attributed to genetic polymorphisms. Therefore, we investigated the association among three polymorphisms in the endothelial nitric oxide gene (-786T>C, 4b4a, and 894G>T), analyzed individually and as haplotypes, and the parasympathetic adaptation induced by exercise training. Eighty healthy males, age 20-35 yr, were genotyped by polymerase chain reaction-restriction fragment length polymorphism analysis, and haplotypes were inferred using the software PHASE 2.1. Autonomic modulation (i.e., HR variability and spontaneous baroreflex sensitivity) and peak oxygen consumption (VO(2peak)) were measured before and after training (running, moderate to severe intensity, three times per week, 60 min·day(-1), during 18 wk). Training increased VO(2peak) (P baroreflex sensitivity after training (change: wild type (-786TT) = 2% ± 89% vs polymorphic (-786TC/CC) = -28% ± 60%, median ± quartile range, P = 0.03), and parasympathetic modulation was marginally reduced in subjects with the 894T polymorphic allele (change: wild type (894GG) = 8% ± 67% vs polymorphic (894GT/TT) = -18% ± 59%, median ± quartile range, P = 0.06). Furthermore, parasympathetic modulation percent change was different between the haplotypes containing wild-type alleles (-786T/4b/894G) and polymorphic alleles at positions -786 and 894 (-786C/4b/894T) (-6% ± 56% vs -41% ± 50%, median ± quartile range, P = 0.04). The polymorphic allele at position -786 and the haplotype containing polymorphic alleles at positions -786 and 894 in the endothelial nitric oxide gene were associated with decreased parasympathetic modulation after exercise training.

  5. Conditioned Medium from Placental Mesenchymal Stem Cells Reduces Oxidative Stress during the Cryopreservation of Ex Vivo Expanded Umbilical Cord Blood Cells.

    Science.gov (United States)

    Kadekar, Darshana; Rangole, Sonal; Kale, Vaijayanti; Limaye, Lalita

    2016-01-01

    The limited cell dose in umbilical cord blood (UCB) necessitates ex vivo expansion of UCB. Further, the effective cryopreservation of these expanded cells is important in widening their use in the clinics. During cryopreservation, cells experience oxidative stress due to the generation of reactive oxygen species (ROS). Conditioned medium from mesenchymal stem cells (MSCs-CM) has been shown to alleviate the oxidative stress during wound healing, Alzheimer's disease and ischemic disease. This premise prompted us to investigate the influence of MSCs-CM during cryopreservation of expanded UCB cells. CM-was collected from cord/placental MSCs(C-MSCs-CM, P-MSC-CM). UCB CD34+cells were expanded as suspension cultures in serum free medium containing cytokines for 10 days. Cells were frozen with/without C-MSCs-CM and or P-MSCs-CM in the conventional freezing medium containing 20%FCS +10%DMSO using a programmable freezer and stored in liquid nitrogen. Upon revival, cells frozen with MSCs-CM were found to be superior to cells frozen in conventional medium in terms of viability, CD34+content and clonogenecity. Priming of revived cells for 48 hrs with MSCs-CM further improved their transplantation ability, as compared to those cultured without MSCs-CM. P-MSCs-CM radically reduced the oxidative stress in cryopreserved cells, resulting in better post thaw functionality of CD34+ cells than with C-MSCs-CM. The observed cryoprotective effect of MSCs-CM was primarily due to anti-oxidative and anti-apoptotic properties of the MSCs-CM and not because of the exosomes secreted by them. Our data suggest that MSCs-CM can serve as a valuable additive to the freezing or the priming medium for expanded UCB cells, which would increase their clinical applicability.

  6. Conditioned Medium from Placental Mesenchymal Stem Cells Reduces Oxidative Stress during the Cryopreservation of Ex Vivo Expanded Umbilical Cord Blood Cells.

    Directory of Open Access Journals (Sweden)

    Darshana Kadekar

    Full Text Available The limited cell dose in umbilical cord blood (UCB necessitates ex vivo expansion of UCB. Further, the effective cryopreservation of these expanded cells is important in widening their use in the clinics. During cryopreservation, cells experience oxidative stress due to the generation of reactive oxygen species (ROS. Conditioned medium from mesenchymal stem cells (MSCs-CM has been shown to alleviate the oxidative stress during wound healing, Alzheimer's disease and ischemic disease. This premise prompted us to investigate the influence of MSCs-CM during cryopreservation of expanded UCB cells.CM-was collected from cord/placental MSCs(C-MSCs-CM, P-MSC-CM. UCB CD34+cells were expanded as suspension cultures in serum free medium containing cytokines for 10 days. Cells were frozen with/without C-MSCs-CM and or P-MSCs-CM in the conventional freezing medium containing 20%FCS +10%DMSO using a programmable freezer and stored in liquid nitrogen. Upon revival, cells frozen with MSCs-CM were found to be superior to cells frozen in conventional medium in terms of viability, CD34+content and clonogenecity. Priming of revived cells for 48 hrs with MSCs-CM further improved their transplantation ability, as compared to those cultured without MSCs-CM. P-MSCs-CM radically reduced the oxidative stress in cryopreserved cells, resulting in better post thaw functionality of CD34+ cells than with C-MSCs-CM. The observed cryoprotective effect of MSCs-CM was primarily due to anti-oxidative and anti-apoptotic properties of the MSCs-CM and not because of the exosomes secreted by them.Our data suggest that MSCs-CM can serve as a valuable additive to the freezing or the priming medium for expanded UCB cells, which would increase their clinical applicability.

  7. Land Application of Wastes: An Educational Program. Soil as a Treatment Medium - Module 3, Objectives, Script and Booklet.

    Science.gov (United States)

    Clarkson, W. W.; And Others

    This module examines the basic properties of soil which have an influence on the success of land treatment of wastes. These relevant properties include soil texture, soil structure, permeability, infiltration, available water capacity, and cation exchange capacity. Biological, chemical and physical mechanisms work to remove and renovate wastes…

  8. Redox homeostasis in stomach medium by foods: The Postprandial Oxidative Stress Index (POSI) for balancing nutrition and human health.

    Science.gov (United States)

    Kanner, Joseph; Selhub, Jacob; Shpaizer, Adi; Rabkin, Boris; Shacham, Inbal; Tirosh, Oren

    2017-08-01

    Red-meat lipid peroxidation in the stomach results in postprandial oxidative stress (POS) which is characterized by the generation of a variety of reactive cytotoxic aldehydes including malondialdehyde (MDA). MDA is absorbed in the blood system reacts with cell proteins to form adducts resulting in advanced lipid peroxidation end products (ALEs), producing dysfunctional proteins and cellular responses. The pathological consequences of ALEs tissue damage include inflammation and increased risk for many chronic diseases that are associated with a Western-type diet. In earlier studies we used the simulated gastric fluid (SGF) condition to show that the in vitro generation of MDA from red meat closely resembles that in human blood after consumption the same amount of meat. In vivo and in vitro MDA generations were similarly suppressed by polyphenol-rich beverages (red wine and coffee) consumed with the meal. The present study uses the in vitro SGF to assess the capacity of more than 50 foods of plant origin to suppress red meat peroxidation and formation of MDA. The results were calculated as reducing POS index (rPOSI) which represents the capacity in percent of 100g of the food used to inhibit lipid peroxidation of 200g red-meat a POSI enhancer (ePOSI). The index permitted to extrapolate the need of rPOSI from a food alone or in ensemble such Greek salad, to neutralize an ePOSI in stomach medium, (ePOS-rPOSI=0). The correlation between the rPOSI and polyphenols in the tested foods was R 2 =0.75. The Index was validated by comparison of the predicted rPOSI for a portion of Greek salad or red-wine to real inhibition of POS enhancers. The POS Index permit to better balancing nutrition for human health. Copyright © 2017. Published by Elsevier B.V.

  9. Redox homeostasis in stomach medium by foods: The Postprandial Oxidative Stress Index (POSI for balancing nutrition and human health

    Directory of Open Access Journals (Sweden)

    Joseph Kanner

    2017-08-01

    Full Text Available Red-meat lipid peroxidation in the stomach results in postprandial oxidative stress (POS which is characterized by the generation of a variety of reactive cytotoxic aldehydes including malondialdehyde (MDA. MDA is absorbed in the blood system reacts with cell proteins to form adducts resulting in advanced lipid peroxidation end products (ALEs, producing dysfunctional proteins and cellular responses. The pathological consequences of ALEs tissue damage include inflammation and increased risk for many chronic diseases that are associated with a Western-type diet. In earlier studies we used the simulated gastric fluid (SGF condition to show that the in vitro generation of MDA from red meat closely resembles that in human blood after consumption the same amount of meat. In vivo and in vitro MDA generations were similarly suppressed by polyphenol-rich beverages (red wine and coffee consumed with the meal. The present study uses the in vitro SGF to assess the capacity of more than 50 foods of plant origin to suppress red meat peroxidation and formation of MDA. The results were calculated as reducing POS index (rPOSI which represents the capacity in percent of 100 g of the food used to inhibit lipid peroxidation of 200 g red-meat a POSI enhancer (ePOSI. The index permitted to extrapolate the need of rPOSI from a food alone or in ensemble such Greek salad, to neutralize an ePOSI in stomach medium, (ePOS–rPOSI=0. The correlation between the rPOSI and polyphenols in the tested foods was R2=0.75. The Index was validated by comparison of the predicted rPOSI for a portion of Greek salad or red-wine to real inhibition of POS enhancers. The POS Index permit to better balancing nutrition for human health.

  10. Polyphenols as Modulator of Oxidative Stress in Cancer Disease: New Therapeutic Strategies

    Science.gov (United States)

    Mileo, Anna Maria; Miccadei, Stefania

    2016-01-01

    Cancer onset and progression have been linked to oxidative stress by increasing DNA mutations or inducing DNA damage, genome instability, and cell proliferation and therefore antioxidant agents could interfere with carcinogenesis. It is well known that conventional radio-/chemotherapies influence tumour outcome through ROS modulation. Since these antitumour treatments have important side effects, the challenge is to develop new anticancer therapeutic strategies more effective and less toxic for patients. To this purpose, many natural polyphenols have emerged as very promising anticancer bioactive compounds. Beside their well-known antioxidant activities, several polyphenols target epigenetic processes involved in cancer development through the modulation of oxidative stress. An alternative strategy to the cytotoxic treatment is an approach leading to cytostasis through the induction of therapy-induced senescence. Many anticancer polyphenols cause cellular growth arrest through the induction of a ROS-dependent premature senescence and are considered promising antitumour therapeutic tools. Furthermore, one of the most innovative and interesting topics is the evaluation of efficacy of prooxidant therapies on cancer stem cells (CSCs). Several ROS inducers-polyphenols can impact CSCs metabolisms and self-renewal related pathways. Natural polyphenol roles, mainly in chemoprevention and cancer therapies, are described and discussed in the light of the current literature data. PMID:26649142

  11. Temperature-modulated graphene oxide resistive humidity sensor for indoor air quality monitoring

    Science.gov (United States)

    de Luca, A.; Santra, S.; Ghosh, R.; Ali, S. Z.; Gardner, J. W.; Guha, P. K.; Udrea, F.

    2016-02-01

    In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary-metal-oxide-semiconductor (CMOS) micro-electro-mechanical-system (MEMS) micro-hotplate technology for the monitoring and control of indoor air quality (IAQ). GO powder is obtained by chemical exfoliation, dispersed in water and deposited via ink-jet printing onto a low power micro-hotplate. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) show the typical layered and wrinkled morphology of the GO. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and Fourier transform infra-red (FTIR) spectroscopy indicate that the GO flakes possess a significant number of oxygen containing functional groups (epoxy, carbonyl, hydroxyl) extremely attractive for humidity detection. Electro-thermal characterisation of the micro-hotplates shows a thermal efficiency of 0.11 mW per °C, resulting in a sensor DC power consumption of only 2.75 mW at 50 °C. When operated in an isothermal mode, the sensor response is detrimentally affected by significant drift, hysteretic behaviour, slow response/recovery times and hence poor RH level discrimination. Conversely, a temperature modulation technique coupled with a differential readout methodology results in a significant reduction of the sensor drift, improved linear response with a sensitivity of 0.14 mV per %, resolution below 5%, and a maximum hysteresis of +/-5% response and recovery times equal to 189 +/- 49 s and 89 +/- 5 s, respectively. These performance parameters satisfy current IAQ monitoring requirements. We have thus demonstrated the effectiveness of integrating GO on a micro-hotplate CMOS-compatible platform enabling temperature modulation schemes to be easily applied in order to achieve compact, low power, low cost humidity IAQ monitoring.In this paper we present a temperature-modulated graphene oxide (GO) resistive humidity sensor that employs complementary-metal-oxide

  12. Melatonin attenuates oxidative stress and modulates inflammatory response after experimental burn trauma

    Directory of Open Access Journals (Sweden)

    Minka Hristova

    2018-04-01

    Full Text Available Introduction. Thermal injury activates an inflammatory response. Melatonin possesses anti-oxidant and anti-inflammatory properties. The objective of the present work was to study melatonin effects on the inflammatory response under conditions of oxidative stress during the early stage of thermal injury. Materials and methods. We used 24 white male rats of Wistar breed, randomly divided into three experimental groups. Group one was the control, group two was inflicted with burn trauma, and group three was inflicted with burn trauma, with melatonin application following the thermal injury. Melatonin was applied twice in doses of 10 g/kg b.m. immediately after the burn trauma and again at 12 hours. Plasma levels of tumor necrosis-factor-α (TNF-α, a pro-inflammatory mediator, and of interleukin-10 (Il-10, an anti-inflammatory mediator, were examined and their ratio was calculated. The levels of malondialdehyde (MDA, an oxidative stress marker, were also estimated. Results. Thermal trauma significantly increased plasma TNF-α levels (ð<0.01 and TNF-α /IL10 ratio but did not change IL-10 ones. Plasma MDA concentrations were significantly elevated as well (ð<0.0001. Melatonin application significantly reduced TNF-α (ð<0.05, increased IL-10 (ð<0.05, down-regulated TNF-α/IL-10 ratio and changed MDA concentrations (ð<0.01. In conclusion, our results show that local alteration induces oxidative stress and inflammatory response with TNF-α /IL-10 disbalance. Melatonin modulates this response and attenuates oxidative stress in experimental burn injury.

  13. A High Temperature Experimental Characterization Procedure for Oxide-Based Thermoelectric Generator Modules under Transient Conditions

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    Elena Anamaria Man

    2015-11-01

    Full Text Available The purpose of this study is to analyze the steady-state and transient behavior of the electrical and thermal parameters of thermoelectric generators (TEGs. The focus is on the required wait-time between measurements in order to reduce measurement errors which may appear until the system reaches steady-state. By knowing this waiting time, the total characterization time can also be reduced. The experimental characterization process is performed on a test rig known as TEGeta, which can be used to assess the output characteristics of TEG modules under different load values and temperature conditions. The setup offers the possibility to control the hot side temperature up to 1000 °C with a load variation range value between 0.22–8.13 Ω. A total of ten thermocouples are placed in the setup with the purpose of measuring the temperature in specific points between the heater and the heat sink. Based on the readings, the temperature on the hot and cold side of the modules can be extrapolated. This study provides quantitative data on the minimum waiting time of the temperatures in the surrounding system to reach equilibrium. Laboratory tests are performed on a calcium-manganese oxide module at temperatures between 400 and 800 °C to explore the high temperatures features of the setup.

  14. Unexpected Behavior of Some Nitric Oxide Modulators under Cadmium Excess in Plant Tissue

    Science.gov (United States)

    Kováčik, Jozef; Babula, Petr; Klejdus, Bořivoj; Hedbavny, Josef; Jarošová, Markéta

    2014-01-01

    Various nitric oxide modulators (NO donors - SNP, GSNO, DEA NONOate and scavengers – PTIO, cPTIO) were tested to highlight the role of NO under Cd excess in various ontogenetic stages of chamomile (Matricaria chamomilla). Surprisingly, compared to Cd alone, SNP and PTIO elevated Cd uptake (confirmed also by PhenGreen staining) but depleted glutathione (partially ascorbic acid) and phytochelatins PC2 and PC3 in both older plants (cultured hydroponically) and seedlings (cultured in deionised water). Despite these anomalous impacts, fluorescence staining of NO and ROS confirmed predictable assumptions and revealed reciprocal changes (decrease in NO but increase in ROS after PTIO addition and the opposite after SNP application). Subsequent tests using alternative modulators and seedlings confirmed changes to NO and ROS after application of GSNO and DEA NONOate as mentioned above for SNP while cPTIO altered only NO level (depletion). On the contrary to SNP and PTIO, GSNO, DEA NONOate and cPTIO did not elevate Cd content and phytochelatins (PC2, PC3) were rather elevated. These data provide evidence that various NO modulators are useful in terms of NO and ROS manipulation but interactions with intact plants affect metal uptake and must therefore be used with caution. In this view, cPTIO and DEA NONOate revealed the less pronounced side impacts and are recommended as suitable NO scavenger/donor in plant physiological studies under Cd excess. PMID:24626462

  15. Selected spices and their combination modulate hypercholesterolemia-induced oxidative stress in experimental rats

    Directory of Open Access Journals (Sweden)

    Gloria A Otunola

    2014-01-01

    Full Text Available BACKGROUND: Effect of aqueous extracts of Allium sativum (garlic, Zingiber officinale (ginger, Capsicum fructensces (cayenne pepper and their mixture on oxidative stress in rats fed high Cholesterol/high fat diet was investigated. Rats were randomly distributed into six groups (n = 6 and given different dietary/spice treatments. Group 1 standard rat chow (control, group 2, hypercholesterolemic diet plus water, and groups 3, 4, 5, 6, hypercholesterolemic diet with 0.5 ml 200 mg · kg-1 aqueous extracts of garlic, ginger, cayenne pepper or their mixture respectively daily for 4 weeks. RESULTS: Pronounced oxidative stress in the hypercholesterolemic rats evidenced by significant (p < 0.05 increase in MDA levels, and suppression of the antioxidant enzymes system in rat's liver, kidney, heart and brain tissues was observed. Extracts of spices singly or combined administered at 200 mg.kg-1 body weight significantly (p < 0.05 reduced MDA levels and restored activities of antioxidant enzymes. CONCLUSIONS: It is concluded that consumption of garlic, ginger, pepper, or their mixture may help to modulate oxidative stress caused by hypercholesterolemia in rats.

  16. Designing and Creating a Synthetic Omega Oxidation Pathway inSaccharomyces cerevisiaeEnables Production of Medium-Chain α, ω-Dicarboxylic Acids.

    Science.gov (United States)

    Han, Li; Peng, Yanfeng; Zhang, Yuangyuan; Chen, Wujiu; Lin, Yuping; Wang, Qinhong

    2017-01-01

    Medium-chain (C8-C14) α, ω-dicarboxylic acids (α, ω-DCAs), which have numerous applications as raw materials for producing various commodities and polymers in chemical industry, are mainly produced from chemical or microbial conversion of petroleum-derived alkanes or plant-derived fatty acids at present. Recently, significant attention has been gained to microbial production of medium-chain α, ω-DCAs from simple renewable sugars. Here, we designed and created a synthetic omega oxidation pathway in Saccharomyces cerevisiae to produce C10 and C12 α, ω-DCAs from renewable sugars and fatty acids by introducing a heterogeneous cytochrome P450 CYP94C1 and cytochrome reductase ATR1. Furthermore, the deletion of fatty acyl-CoA synthetase genes FAA1 and FAA4 increased the production of medium-chain α, ω-DCAs from 4.690 ± 0.088 mg/L to 12.177 ± 0.420 mg/L and enabled the production of C14 and C16 α, ω-DCAs at low percentage. But blocking β-oxidation pathway by deleting fatty-acyl coenzyme A oxidase gene POX1 and overexpressing different thioesterase genes had no significant impact on the production and the composition of α, ω-dicarboxylic acids. Overall, our study indicated the potential of microbial production of medium-chain α, ω-DCAs from renewable feedstocks using engineered yeast.

  17. Polarization-Insensitive Surface Plasmon Polarization Electro-Absorption Modulator Based on Epsilon-Near-Zero Indium Tin Oxide.

    Science.gov (United States)

    Jin, Lin; Wen, Long; Liang, Li; Chen, Qin; Sun, Yunfei

    2018-02-03

    CMOS-compatible plasmonic modulators operating at the telecom wavelength are significant for a variety of on-chip applications. Relying on the manipulation of the transverse magnetic (TM) mode excited on the metal-dielectric interface, most of the previous demonstrations are designed to response only for specific polarization state. In this case, it will lead to a high polarization dependent loss, when the polarization-sensitive modulator integrates to a fiber with random polarization state. Herein, we propose a plasmonic modulator utilizing a metal-oxide indium tin oxide (ITO) wrapped around the silicon waveguide and investigate its optical modulation ability for both the vertical and horizontal polarized guiding light by tuning electro-absorption of ITO with the field-induced carrier injection. The electrically biased modulator with electron accumulated at the ITO/oxide interface allows for epsilon-near-zero (ENZ) mode to be excited at the top or lateral portion of the interface depending on the polarization state of the guiding light. Because of the high localized feature of ENZ mode, efficient electro-absorption can be achieved under the "OFF" state of the device, thus leading to large extinction ratio (ER) for both polarizations in our proposed modulator. Further, the polarization-insensitive modulation is realized by properly tailoring the thickness of oxide in two different stacking directions and therefore matching the ER values for device operating at vertical and horizontal polarized modes. For the optimized geometry configuration, the difference between the ER values of two polarization modes, i.e., the ΔER, as small as 0.01 dB/μm is demonstrated and, simultaneously with coupling efficiency above 74%, is obtained for both polarizations at a wavelength of 1.55 μm. The proposed plasmonic-combined modulator has a potential application in guiding and processing of light from a fiber with a random polarization state.

  18. Polarization-Insensitive Surface Plasmon Polarization Electro-Absorption Modulator Based on Epsilon-Near-Zero Indium Tin Oxide

    Science.gov (United States)

    Jin, Lin; Wen, Long; Liang, Li; Chen, Qin; Sun, Yunfei

    2018-02-01

    CMOS-compatible plasmonic modulators operating at the telecom wavelength are significant for a variety of on-chip applications. Relying on the manipulation of the transverse magnetic (TM) mode excited on the metal-dielectric interface, most of the previous demonstrations are designed to response only for specific polarization state. In this case, it will lead to a high polarization dependent loss, when the polarization-sensitive modulator integrates to a fiber with random polarization state. Herein, we propose a plasmonic modulator utilizing a metal-oxide indium tin oxide (ITO) wrapped around the silicon waveguide and investigate its optical modulation ability for both the vertical and horizontal polarized guiding light by tuning electro-absorption of ITO with the field-induced carrier injection. The electrically biased modulator with electron accumulated at the ITO/oxide interface allows for epsilon-near-zero (ENZ) mode to be excited at the top or lateral portion of the interface depending on the polarization state of the guiding light. Because of the high localized feature of ENZ mode, efficient electro-absorption can be achieved under the "OFF" state of the device, thus leading to large extinction ratio (ER) for both polarizations in our proposed modulator. Further, the polarization-insensitive modulation is realized by properly tailoring the thickness of oxide in two different stacking directions and therefore matching the ER values for device operating at vertical and horizontal polarized modes. For the optimized geometry configuration, the difference between the ER values of two polarization modes, i.e., the ΔER, as small as 0.01 dB/μm is demonstrated and, simultaneously with coupling efficiency above 74%, is obtained for both polarizations at a wavelength of 1.55 μm. The proposed plasmonic-combined modulator has a potential application in guiding and processing of light from a fiber with a random polarization state.

  19. Anti-Vascular Endothelial Growth Factors Protect Retinal Pigment Epithelium Cells Against Oxidation by Modulating Nitric Oxide Release and Autophagy

    Directory of Open Access Journals (Sweden)

    Stefano De Cillà

    2017-07-01

    Full Text Available Background/Aims: the anti-vascular endothelial growth factors (VEGF, Aflibercept and Ranibizumab, are used for the treatment of macular degeneration. Here we examined the involvement of nitric oxide (NO, mitochondria function and of apoptosis/autophagy in their antioxidant effects in human retinal pigment epithelium cells (RPE. Methods: RPE were exposed to Ranibizumab/Aflibercept in the absence or presence of NO synthase (NOS inhibitor and of autophagy activator/blocker, rapamicyn/3-methyladenine. Specific kits were used for cell viability, NO and reactive oxygen species detection and mitochondrial membrane potential measurement, whereas Western Blot was performed for apoptosis/ autophagy markers and other kinases detection. Results: In RPE cultured in physiological conditions, Aflibercept/Ranibizumab increased NO release in a dose and time-dependent way. Opposite results were obtained in RPE pretreated with hydrogen peroxide. Moreover, both the anti-VEGF agents were able to prevent the fall of cell viability and of mitochondrial membrane potential. Those effects were reduced by the NOS inhibitor and 3-methyladenine and were potentiated by rapamycin. Finally, Aflibercept and Ranibizumab counteracted the changes of apoptosis/autophagy markers, NOS, Phosphatidylinositol-3-Kinase/Protein Kinase B and Extracellular signal–regulated kinases 1/2 caused by peroxidation. Conclusion: Aflibercept and Ranibizumab protect RPE against peroxidation through the modulation of NO release, apoptosis and autophagy.

  20. Hypotheses on the Potential of Rice Bran Intake to Prevent Gastrointestinal Cancer through the Modulation of Oxidative Stress

    OpenAIRE

    Law, Bernard M. H.; Waye, Mary M. Y.; So, Winnie K. W.; Chair, Sek Ying

    2017-01-01

    Previous studies have suggested the potential involvement of oxidative stress in gastrointestinal cancers. In light of this, research efforts have been focused on the potential of dietary antioxidant intake to prevent gastrointestinal cancer through the modulation of oxidative stress. Rice bran, a by-product of rice milling, has been shown to contain an abundance of phytochemicals, which are dietary antioxidants. To date, a number of studies have shown the antioxidative effect of rice bran in...

  1. Electrochemical Oxidation of Resorcinol in Aqueous Medium Using Boron-Doped Diamond Anode: Reaction Kinetics and Process Optimization with Response Surface Methodology.

    Science.gov (United States)

    Körbahti, Bahadır K; Demirbüken, Pelin

    2017-01-01

    Electrochemical oxidation of resorcinol in aqueous medium using boron-doped diamond anode (BDD) was investigated in a batch electrochemical reactor in the presence of Na 2 SO 4 supporting electrolyte. The effect of process parameters such as resorcinol concentration (100-500 g/L), current density (2-10 mA/cm 2 ), Na 2 SO 4 concentration (0-20 g/L), and reaction temperature (25-45°C) was analyzed on electrochemical oxidation using response surface methodology (RSM). The optimum operating conditions were determined as 300 mg/L resorcinol concentration, 8 mA/cm 2 current density, 12 g/L Na 2 SO 4 concentration, and 34°C reaction temperature. One hundred percent of resorcinol removal and 89% COD removal were obtained in 120 min reaction time at response surface optimized conditions. These results confirmed that the electrochemical mineralization of resorcinol was successfully accomplished using BDD anode depending on the process conditions, however the formation of intermediates and by-products were further oxidized at much lower rate. The reaction kinetics were evaluated at optimum conditions and the reaction order of electrochemical oxidation of resorcinol in aqueous medium using BDD anode was determined as 1 based on COD concentration with the activation energy of 5.32 kJ/mol that was supported a diffusion-controlled reaction.

  2. Electrochemical Oxidation of Resorcinol in Aqueous Medium Using Boron-Doped Diamond Anode: Reaction Kinetics and Process Optimization with Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Bahadır K. Körbahti

    2017-10-01

    Full Text Available Electrochemical oxidation of resorcinol in aqueous medium using boron-doped diamond anode (BDD was investigated in a batch electrochemical reactor in the presence of Na2SO4 supporting electrolyte. The effect of process parameters such as resorcinol concentration (100–500 g/L, current density (2–10 mA/cm2, Na2SO4 concentration (0–20 g/L, and reaction temperature (25–45°C was analyzed on electrochemical oxidation using response surface methodology (RSM. The optimum operating conditions were determined as 300 mg/L resorcinol concentration, 8 mA/cm2 current density, 12 g/L Na2SO4 concentration, and 34°C reaction temperature. One hundred percent of resorcinol removal and 89% COD removal were obtained in 120 min reaction time at response surface optimized conditions. These results confirmed that the electrochemical mineralization of resorcinol was successfully accomplished using BDD anode depending on the process conditions, however the formation of intermediates and by-products were further oxidized at much lower rate. The reaction kinetics were evaluated at optimum conditions and the reaction order of electrochemical oxidation of resorcinol in aqueous medium using BDD anode was determined as 1 based on COD concentration with the activation energy of 5.32 kJ/mol that was supported a diffusion-controlled reaction.

  3. Biofunctionalized Zinc Oxide Field Effect Transistors for Selective Sensing of Riboflavin with Current Modulation

    Directory of Open Access Journals (Sweden)

    Morley O. Stone

    2011-06-01

    Full Text Available Zinc oxide field effect transistors (ZnO-FET, covalently functionalized with single stranded DNA aptamers, provide a highly selective platform for label-free small molecule sensing. The nanostructured surface morphology of ZnO provides high sensitivity and room temperature deposition allows for a wide array of substrate types. Herein we demonstrate the selective detection of riboflavin down to the pM level in aqueous solution using the negative electrical current response of the ZnO-FET by covalently attaching a riboflavin binding aptamer to the surface. The response of the biofunctionalized ZnO-FET was tuned by attaching a redox tag (ferrocene to the 3’ terminus of the aptamer, resulting in positive current modulation upon exposure to riboflavin down to pM levels.

  4. Nitric oxide synthase modulates CFA-induced thermal hyperalgesia through cytokine regulation in mice.

    Science.gov (United States)

    Chen, Yong; Boettger, Michael K; Reif, Andreas; Schmitt, Angelika; Uçeyler, Nurcan; Sommer, Claudia

    2010-03-02

    Although it has been largely demonstrated that nitric oxide synthase (NOS), a key enzyme for nitric oxide (NO) production, modulates inflammatory pain, the molecular mechanisms underlying these effects remain to be clarified. Here we asked whether cytokines, which have well-described roles in inflammatory pain, are downstream targets of NO in inflammatory pain and which of the isoforms of NOS are involved in this process. Intraperitoneal (i.p.) pretreatment with 7-nitroindazole sodium salt (7-NINA, a selective neuronal NOS inhibitor), aminoguanidine hydrochloride (AG, a selective inducible NOS inhibitor), L-N(G)-nitroarginine methyl ester (L-NAME, a non-selective NOS inhibitor), but not L-N(5)-(1-iminoethyl)-ornithine (L-NIO, a selective endothelial NOS inhibitor), significantly attenuated thermal hyperalgesia induced by intraplantar (i.pl.) injection of complete Freund's adjuvant (CFA). Real-time reverse transcription-polymerase chain reaction (RT-PCR) revealed a significant increase of nNOS, iNOS, and eNOS gene expression, as well as tumor necrosis factor-alpha (TNF), interleukin-1 beta (IL-1beta), and interleukin-10 (IL-10) gene expression in plantar skin, following CFA. Pretreatment with the NOS inhibitors prevented the CFA-induced increase of the pro-inflammatory cytokines TNF and IL-1beta. The increase of the anti-inflammatory cytokine IL-10 was augmented in mice pretreated with 7-NINA or L-NAME, but reduced in mice receiving AG or L-NIO. NNOS-, iNOS- or eNOS-knockout (KO) mice had lower gene expression of TNF, IL-1beta, and IL-10 following CFA, overall corroborating the inhibitor data. These findings lead us to propose that inhibition of NOS modulates inflammatory thermal hyperalgesia by regulating cytokine expression.

  5. Nitric oxide synthase modulates CFA-induced thermal hyperalgesia through cytokine regulation in mice

    Directory of Open Access Journals (Sweden)

    Üçeyler Nurcan

    2010-03-01

    Full Text Available Abstract Background Although it has been largely demonstrated that nitric oxide synthase (NOS, a key enzyme for nitric oxide (NO production, modulates inflammatory pain, the molecular mechanisms underlying these effects remain to be clarified. Here we asked whether cytokines, which have well-described roles in inflammatory pain, are downstream targets of NO in inflammatory pain and which of the isoforms of NOS are involved in this process. Results Intraperitoneal (i.p. pretreatment with 7-nitroindazole sodium salt (7-NINA, a selective neuronal NOS inhibitor, aminoguanidine hydrochloride (AG, a selective inducible NOS inhibitor, L-N(G-nitroarginine methyl ester (L-NAME, a non-selective NOS inhibitor, but not L-N(5-(1-iminoethyl-ornithine (L-NIO, a selective endothelial NOS inhibitor, significantly attenuated thermal hyperalgesia induced by intraplantar (i.pl. injection of complete Freund's adjuvant (CFA. Real-time reverse transcription-polymerase chain reaction (RT-PCR revealed a significant increase of nNOS, iNOS, and eNOS gene expression, as well as tumor necrosis factor-alpha (TNF, interleukin-1 beta (IL-1β, and interleukin-10 (IL-10 gene expression in plantar skin, following CFA. Pretreatment with the NOS inhibitors prevented the CFA-induced increase of the pro-inflammatory cytokines TNF and IL-1β. The increase of the anti-inflammatory cytokine IL-10 was augmented in mice pretreated with 7-NINA or L-NAME, but reduced in mice receiving AG or L-NIO. NNOS-, iNOS- or eNOS-knockout (KO mice had lower gene expression of TNF, IL-1β, and IL-10 following CFA, overall corroborating the inhibitor data. Conclusion These findings lead us to propose that inhibition of NOS modulates inflammatory thermal hyperalgesia by regulating cytokine expression.

  6. Iron Oxide Nanoparticle Agglomeration Influences Dose-Rates and Modulates Oxidative Stress Mediated Dose-Response Profiles In Vitro

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Gaurav; Kodali, Vamsi K.; Gaffrey, Matthew J.; Wang, Wei; Minard, Kevin R.; Karin, Norman J.; Teeguarden, Justin G.; Thrall, Brian D.

    2013-07-31

    Spontaneous agglomeration of engineered nanoparticles (ENPs) is a common problem in cell culture media which can confound interpretation of in vitro nanotoxicity studies. The authors created stable agglomerates of iron oxide nanoparticles (IONPs) in conventional culture medium, which varied in hydrodynamic size (276 nm-1.5 μm) but were composed of identical primary particles with similar surface potentials and protein coatings. Studies using C10 lung epithelial cells show that the dose rate effects of agglomeration can be substantial, varying by over an order of magnitude difference in cellular dose in some cases. Quantification by magnetic particle detection showed that small agglomerates of carboxylated IONPs induced greater cytotoxicity and redox-regulated gene expression when compared with large agglomerates on an equivalent total cellular IONP mass dose basis, whereas agglomerates of amine-modified IONPs failed to induce cytotoxicity or redox-regulated gene expression despite delivery of similar cellular doses. Dosimetry modelling and experimental measurements reveal that on a delivered surface area basis, large and small agglomerates of carboxylated IONPs have similar inherent potency for the generation of ROS, induction of stress-related genes and eventual cytotoxicity. The results suggest that reactive moieties on the agglomerate surface are more efficient in catalysing cellular ROS production than molecules buried within the agglomerate core. Because of the dynamic, size and density-dependent nature of ENP delivery to cells in vitro, the biological consequences of agglomeration are not discernible from static measures of exposure concentration (μg/ml) alone, highlighting the central importance of integrated physical characterisation and quantitative dosimetry for in vitro studies. The combined experimental and computational approach provides a quantitative framework for evaluating relationships between the biocompatibility of nanoparticles and their

  7. Iron oxide nanoparticle agglomeration influences dose rates and modulates oxidative stress-mediated dose–response profiles in vitro

    Science.gov (United States)

    Sharma, Gaurav; Kodali, Vamsi; Gaffrey, Matthew; Wang, Wei; Minard, Kevin R.; Karin, Norman J.; Teeguarden, Justin G.; Thrall, Brian D.

    2014-01-01

    Spontaneous agglomeration of engineered nanoparticles (ENPs) is a common problem in cell culture media which can confound interpretation of in vitro nanotoxicity studies. The authors created stable agglomerates of iron oxide nanoparticles (IONPs) in conventional culture medium, which varied in hydrodynamic size (276 nm–1.5 μm) but were composed of identical primary particles with similar surface potentials and protein coatings. Studies using C10 lung epithelial cells show that the dose rate effects of agglomeration can be substantial, varying by over an order of magnitude difference in cellular dose in some cases. Quantification by magnetic particle detection showed that small agglomerates of carboxylated IONPs induced greater cytotoxicity and redox-regulated gene expression when compared with large agglomerates on an equivalent total cellular IONP mass dose basis, whereas agglomerates of amine-modified IONPs failed to induce cytotoxicity or redox-regulated gene expression despite delivery of similar cellular doses. Dosimetry modelling and experimental measurements reveal that on a delivered surface area basis, large and small agglomerates of carboxylated IONPs have similar inherent potency for the generation of ROS, induction of stress-related genes and eventual cytotoxicity. The results suggest that reactive moieties on the agglomerate surface are more efficient in catalysing cellular ROS production than molecules buried within the agglomerate core. Because of the dynamic, size and density-dependent nature of ENP delivery to cells in vitro, the biological consequences of agglomeration are not discernible from static measures of exposure concentration (μg/ml) alone, highlighting the central importance of integrated physical characterisation and quantitative dosimetry for in vitro studies. The combined experimental and computational approach provides a quantitative framework for evaluating relationships between the biocompatibility of nanoparticles and their

  8. The Role of Nitric Oxide in Memory is Modulated by Diurnal Time

    Directory of Open Access Journals (Sweden)

    Stephanie L. Gage

    2014-04-01

    Full Text Available Nitric oxide (NO is thought to play an important neuromodulatory role in the olfactory system. This modulation has been suggested to be particularly important for olfactory learning and memory in the antennal lobe (the primary olfactory network in invertebrates. We are using the hawkmoth, Manduca sexta, to further investigate the role of NO in olfactory memory. Recent findings suggest that NO affects short-term memory traces and that NO concentration fluctuates with the light cycle. This gives rise to the hypothesis that NO may be involved in the connection between memory and circadian rhythms. In this study, we explore the role of diurnal time and NO in memory by altering the time of day when associative-olfactory conditioning is performed. We find a strong effect of NO on short-term memory, and two surprising effects of diurnal time. We find that (1 at certain time points, NO affects longer traces of memory in addition to short-term memory, and (2 when conditioning is performed close to the light cycle switches—both from light to dark and dark to light—NO does not significantly affect memory at all. These findings suggest an intriguing functional role for NO in olfactory conditioning that is modulated as a function of diurnal time.

  9. Thermoelectric Oxide Modules (TOMs for the Direct Conversion of Simulated Solar Radiation into Electrical Energy

    Directory of Open Access Journals (Sweden)

    Petr Tomeš

    2010-04-01

    Full Text Available The direct conversion of concentrated high temperature solar heat into electrical energy was demonstrated with a series of four–leg thermoelectric oxide modules (TOM. These temperature stable modules were not yet optimized for high efficiency conversion, but served as proof-of-principle for high temperature conversion. They were constructed by connecting two p- (La1.98Sr0.02CuO4 and two n-type (CaMn0.98Nb0.02O3 thermoelements electrically in series and thermally in parallel. The temperature gradient ΔT was applied by a High–Flux Solar Simulator source (HFSS which generates a spectrum similar to solar radiation. The influence of the graphite layer coated on the hot side of the Al2O3 substrate compared to the uncoated surface on ΔT, Pmax and η was studied in detail. The measurements show an almost linear temperature profile along the thermoelectric legs. The maximum output power of 88.8 mW was reached for a TOM with leg length of 5 mm at ΔT = 622 K. The highest conversion efficiency η was found for a heat flux of 4–8 W cm-2 and the dependence of η on the leg length was investigated.

  10. Scale-Up Design Analysis and Modelling of Cobalt Oxide Silica Membrane Module for Hydrogen Processing

    Directory of Open Access Journals (Sweden)

    Guozhao Ji

    2013-08-01

    Full Text Available This work shows the application of a validated mathematical model for gas permeation at high temperatures focusing on demonstrated scale-up design for H2 processing. The model considered the driving force variation with spatial coordinates and the mass transfer across the molecular sieve cobalt oxide silica membrane to predict the separation performance. The model was used to study the process of H2 separation at 500 °C in single and multi-tube membrane modules. Parameters of interest included the H2 purity in the permeate stream, H2 recovery and H2 yield as a function of the membrane length, number of tubes in a membrane module, space velocity and H2 feed molar fraction. For a single tubular membrane, increasing the length of a membrane tube led to higher H2 yield and H2 recovery, owing to the increase of the membrane area. However, the H2 purity decreased as H2 fraction was depleted, thus reducing the driving force for H2 permeation. By keeping the membrane length constant in a multi-tube arrangement, the H2 yield and H2 recovery increase was attributed to the higher membrane area, but the H2 purity was again compromised. Increasing the space velocity avoided the reduction of H2 purity and still delivered higher H2 yield and H2 recovery than in a single membrane arrangement. Essentially, if the membrane surface is too large, the driving force becomes lower at the expense of H2 purity. In this case, the membrane module is over designed. Hence, maintaining a driving force is of utmost importance to deliver the functionality of process separation.

  11. NaCl concentration in the medium modulates the secretion of active EmpA protease in Vibrio anguillarum at post-transcriptional level.

    Science.gov (United States)

    Crisafi, F; Denaro, R; Yakimov, M; Felice, M R; Giuliano, L; Genovese, L

    2015-12-01

    This study focused on the influence of different amounts of NaCl in the medium in Vibrio anguillarum EmpA protease production at both the transcriptional and post-transcriptional levels. Vibrio anguillarum 975/I was cultivated in cM9 medium with varying concentrations of NaCl: 0·5, 1·5, 3·0%. EmpA protease was monitored in the supernatants by the skim milk test, azocasein assay and Western blot analysis. The empA gene expression was measured by real-time PCR. A mutant strain 975/I defective for the empA gene confirmed the specificity of the response for EmpA protease. Active protease production was induced by 0·5 and 1·5% NaCl-amended media; however, the strain cultivated in 3·0% NaCl was unable to secrete EmpA protease. The quantitative expression of the empA gene was very similar in all tested conditions. The NaCl concentration in the medium modulates the secretion of active EmpA protease in V. anguillarum at a post-transcriptional level. EmpA protease is one of the most important virulence factors in V. anguillarum. We demonstrated the influence of osmotic changes in the regulation of EmpA protease in the V. anguillarum 975/I strain. This finding has an important impact on the evaluation of factors determining the onset of disease in fish. © 2015 The Society for Applied Microbiology.

  12. Modulator Effect of Turmeric on Oxidative Damage in Whole Body Gamma Irradiated rats

    International Nuclear Information System (INIS)

    Amin, H.H.; Abdou, M.I.

    2012-01-01

    Because of its penetrating power and its ability to travel great distances, gamma rays are considered the primary hazard to the population during most radiological emergencies. So, there is a need to develop medical countermeasures to protect the first responders and remediation workers from biomedical effect of ionizing radiation. Turmeric has been reported to have many beneficial health effects, including a strong anti-oxidant effect, anti-inflammatory and anti-microbial properties. In the present study, turmeric was investigated as a therapeutic agent against hazards induced by ionizing radiation on kidney, liver, urinary and serum calcium levels and blood counts. A daily dose of 0.5 g/kg body weight was used in whole body gamma irradiated female rats with 3 Gy. Radiation effects were followed up for four weeks post irradiation. The results revealed that the administration of turmeric post-irradiation resulted in a significant inhibition in the frequency of radiation induced oxidative damage. It could be concluded that definite turmeric dose exerts a vital modulator role against gamma irradiation hazard

  13. Modulation of physical properties of oxide thin films by multiple fields

    Science.gov (United States)

    Hua-Li, Yang; Bao-Min, Wang; Xiao-Jian, Zhu; Jie, Shang; Bin, Chen; Run-Wei, Li

    2016-06-01

    Recent studies of the modulation of physical properties in oxide thin films by multiple fields are reviewed. Some of the key issues and prospects of this area of study are also addressed. Oxide thin films exhibit versatile physical properties such as magnetism, ferroelectricity, piezoelectricity, metal-insulator transition (MIT), multiferroicity, colossal magnetoresistivity, switchable resistivity. More importantly, the exhibited multifunctionality can be tuned by various external fields, which has enabled demonstration of novel electronic devices. Project supported by the State Key Project of Fundamental Research of China (Grant No. 2012CB933004), the National Natural Science Foundation of China (Grant Nos. 11474295, 51571208, 51525103, and 11274322), Overseas, Hong Kong & Macao Scholars Collaborated Researching Fund (Grant No. 51428201), the Instrument Developing Project of the Chinese Academy of Sciences (Grant No. YZ201327), Ningbo Major Project for Science and Technology (Grant No. 2014B11011), Ningbo International Cooperation Projects (Grant Nos. 2012D10018 and 2014D10005), the Fund for Ningbo Science and Technology Innovation Team (Grant No. 2015B11001), the Youth Innovation Promotion Association of the Chinese Academy of Sciences, and the Key Research Program of the Chinese Academy of Sciences (Grant No. KJZD-EW-M05).

  14. Soluble Iron in Alveolar Macrophages Modulates Iron Oxide Particle-Induced Inflammatory Response via Prostaglandin E2 Synthesis

    Science.gov (United States)

    Ambient particulate matter (PM)-associated metals have been shown to play an important role in cardiopulmonary health outcomes. To study the modulation of inflammation by PM-associated soluble metal, we investigated intracellular solubility of radiolabelled iron oxide (59

  15. Modulating the oxidative environment during mesenchymal stem cells chondrogenesis with serum increases collagen accumulation in agarose culture.

    Science.gov (United States)

    Tangtrongsup, Suwimol; Kisiday, John D

    2018-01-01

    Chondrogenesis of mesenchymal stem cells (MSCs) is induced in culture conditions that have been associated with oxidative stress, although the extent to which the oxidative environment affects differentiation and extracellular matrix (ECM) accumulation is not known. The objectives of this study were to evaluate the oxidative environment during MSCs chondrogenesis in conventional serum-free medium, and the effect of serum-supplementation on intracellular reactive oxygen species (ROS) and chondrogenesis. Young adult equine MSCs were seeded into agarose and cultured in chondrogenic medium, with or without 5% fetal bovine serum (FBS), for up to 15 days. Samples were evaluated for intracellular ROS, the antioxidant glutathione, ECM and gene expression measures of chondrogenesis, and carbonylation as an indicator of oxidative damage. Intracellular ROS increased with time in culture, and was lower in medium supplemented with FBS. Glutathione decreased ∼12-fold during early chondrogenesis (p environment during MSC chondrogenesis, and suggested that lowering ROS may be an effective approach to increase collagen accumulation. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:506-514, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  16. Control of cellular proliferation by modulation of oxidative phosphorylation in human and rodent fast-growing tumor cells

    International Nuclear Information System (INIS)

    Rodriguez-Enriquez, Sara; Vital-Gonzalez, Paola A.; Flores-Rodriguez, Fanny L.; Marin-Hernandez, Alvaro; Ruiz-Azuara, Lena; Moreno-Sanchez, Rafael

    2006-01-01

    The relationship between cell proliferation and the rates of glycolysis and oxidative phosphorylation in HeLa (human) and AS-30D (rodent) tumor cells was evaluated. In glutamine plus glucose medium, both tumor lines grew optimally. Mitochondria were the predominant source of ATP in both cell types (66-75%), despite an active glycolysis. In glucose-free medium with glutamine, proliferation of both lines diminished by 30% but oxidative phosphorylation and the cytosolic ATP level increased by 50%. In glutamine-free medium with glucose, proliferation, oxidative phosphorylation and ATP concentration diminished drastically, although the cells were viable. Oligomycin, in medium with glutamine plus glucose, abolished growth of both tumor lines, indicating an essential role of mitochondrial ATP for tumor progression. The presumed mitochondrial inhibitors rhodamines 123 and 6G, and casiopeina II-gly, inhibited tumor cell proliferation and oxidative phosphorylation, but also glycolysis. In contrast, gossypol, iodoacetate and arsenite strongly blocked glycolysis; however, they did not affect tumor proliferation or mitochondrial metabolism. Growth of both tumor lines was highly sensitive to rhodamines and casiopeina II-gly, with IC 5 values for HeLa cells lower than 0.5 μM, whereas viability and proliferation of human lymphocytes were not affected by these drugs (IC 5 > 30 μM). Moreover, rhodamine 6G and casiopeina II-gly, at micromolar doses, prolonged the survival of animals bearing i.p. implanted AS-30D hepatoma. It is concluded that fast-growing tumor cells have a predominantly oxidative type of metabolism, which might be a potential therapeutic target

  17. Modulating central gain in tinnitus: changes in nitric oxide synthase in the ventral cochlear nucleus.

    Science.gov (United States)

    Coomber, Ben; Kowalkowski, Victoria L; Berger, Joel I; Palmer, Alan Richard; Wallace, Mark Nelson

    2015-01-01

    A significant challenge in tinnitus research lies in explaining how acoustic insult leads to tinnitus in some individuals, but not others. One possibility is genetic variability in the expression and function of neuromodulators - components of neural signaling that alter the balance of excitation and inhibition in neural circuits. An example is nitric oxide (NO) - a free radical and potent neuromodulator in the mammalian brain - that regulates plasticity via both pre-synaptic and postsynaptic mechanisms. Changes in NO have previously been implicated in tinnitus generation, specifically in the ventral cochlear nucleus (VCN). Here, we examined nitric oxide synthase (NOS) - the enzyme responsible for NO production - in the guinea pig VCN following acoustic trauma. NOS was present in most cell types - including spherical and globular bushy cells, small, medium, and large multipolar cells, and octopus cells - spanning the entire extent of the VCN. The staining pattern was symmetrical in control animals. Unilateral acoustic over-exposure (AOE) resulted in marked asymmetries between ipsilateral and contralateral sides of the VCN in terms of the distribution of NOS across the cochlear nuclei in animals with behavioral evidence of tinnitus: fewer NOS-positive cells and a reduced level of NOS staining was present across the whole extent of the contralateral VCN, relative to the ipsilateral VCN. The asymmetric pattern of NOS-containing cells was observed as early as 1 day after AOE and was also present in some animals at 3, 7, and 21 days after AOE. However, it was not until 8 weeks after AOE, when tinnitus had developed, that asymmetries were significant overall, compared with control animals. Asymmetrical NOS expression was not correlated with shifts in the threshold hearing levels. Variability in NOS expression between animals may represent one underlying difference that can be linked to whether or not tinnitus develops after noise exposure.

  18. Modulating central gain in tinnitus: Changes in nitric oxide synthase in the ventral cochlear nucleus

    Directory of Open Access Journals (Sweden)

    Ben eCoomber

    2015-03-01

    Full Text Available A significant challenge in tinnitus research lies in explaining how acoustic insult leads to tinnitus in some individuals, but not others. One possibility is genetic variability in the expression and function of neuromodulators – components of neural signalling that alter the balance of excitation and inhibition in neural circuits. An example is nitric oxide (NO – a free radical and potent neuromodulator in the mammalian brain – that regulates plasticity via both presynaptic and postsynaptic mechanisms. Changes in NO have previously been implicated in tinnitus generation, specifically in the ventral cochlear nucleus (VCN. Here, we examined nitric oxide synthase (NOS – the enzyme responsible for NO production – in the guinea pig VCN following acoustic trauma. NOS was present in most cell types – including spherical and globular bushy cells, small, medium and large multipolar cells, and octopus cells – spanning the entire extent of the VCN. The staining pattern was symmetrical in control animals. Unilateral acoustic over-exposure (AOE resulted in marked asymmetries between ipsilateral and contralateral sides of the VCN in terms of the distribution of NOS across the cochlear nuclei in animals with behavioural evidence of tinnitus: fewer NOS-positive cells and a reduced level of NOS staining was present across the whole extent of the contralateral VCN, relative to the ipsilateral VCN. The asymmetric pattern of NOS-containing cells was observed as early as one day after AOE and was also present in some animals at 3, 7 and 21 days after AOE. However it was not until eight weeks after AOE, when tinnitus had developed, that asymmetries were significant overall, compared with control animals. Asymmetrical NOS expression was not correlated with shifts in the threshold hearing levels. Variability in NOS expression between animals may represent one underlying difference that can be linked to whether or not tinnitus develops after noise

  19. Denitrification-derived nitric oxide modulates biofilm formation in Azospirillum brasilense.

    Science.gov (United States)

    Arruebarrena Di Palma, Andrés; Pereyra, Cintia M; Moreno Ramirez, Lizbeth; Xiqui Vázquez, María L; Baca, Beatriz E; Pereyra, María A; Lamattina, Lorenzo; Creus, Cecilia M

    2013-01-01

    Azospirillum brasilense is a rhizobacterium that provides beneficial effects on plants when they colonize roots. The formation of complex bacterial communities known as biofilms begins with the interaction of planktonic cells with surfaces in response to appropriate signals. Nitric oxide (NO) is a signaling molecule implicated in numerous processes in bacteria, including biofilm formation or dispersion, depending on genera and lifestyle. Azospirillum brasilense Sp245 produces NO by denitrification having a role in root growth promotion. We analyzed the role of endogenously produced NO on biofilm formation in A. brasilense Sp245 and in a periplasmic nitrate reductase mutant (napA::Tn5; Faj164) affected in NO production. Cells were statically grown in media with nitrate or ammonium as nitrogen sources and examined for biofilm formation using crystal violet and by confocal laser microscopy. Both strains formed biofilms, but the mutant produced less than half compared with the wild type in nitrate medium showing impaired nitrite production in this condition. NO measurements in biofilm confirmed lower values in the mutant strain. The addition of a NO donor showed that NO influences biofilm formation in a dose-dependent manner and reverses the mutant phenotype, indicating that Nap positively regulates the formation of biofilm in A. brasilense Sp245. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  20. The oxidative debt of fasting: evidence for short- to medium-term costs of advanced fasting in adult king penguins.

    Science.gov (United States)

    Schull, Quentin; Viblanc, Vincent A; Stier, Antoine; Saadaoui, Hédi; Lefol, Emilie; Criscuolo, François; Bize, Pierre; Robin, Jean-Patrice

    2016-10-15

    In response to prolonged periods of fasting, animals have evolved metabolic adaptations helping to mobilize body reserves and/or reduce metabolic rate to ensure a longer usage of reserves. However, those metabolic changes can be associated with higher exposure to oxidative stress, raising the question of how species that naturally fast during their life cycle avoid an accumulation of oxidative damage over time. King penguins repeatedly cope with fasting periods of up to several weeks. Here, we investigated how adult male penguins deal with oxidative stress after an experimentally induced moderate fasting period (PII) or an advanced fasting period (PIII). After fasting in captivity, birds were released to forage at sea. We measured plasmatic oxidative stress on the same individuals at the start and end of the fasting period and when they returned from foraging at sea. We found an increase in activity of the antioxidant enzyme superoxide dismutase along with fasting. However, PIII individuals showed higher oxidative damage at the end of the fast compared with PII individuals. When they returned from re-feeding at sea, all birds had recovered their initial body mass and exhibited low levels of oxidative damage. Notably, levels of oxidative damage after the foraging trip were correlated to the rate of mass gain at sea in PIII individuals but not in PII individuals. Altogether, our results suggest that fasting induces a transitory exposure to oxidative stress and that effort to recover in body mass after an advanced fasting period may be a neglected carryover cost of fasting. © 2016. Published by The Company of Biologists Ltd.

  1. Kinetics and Mechanism of Electron Transfer Reaction: Oxidation of Sulfanilic Acid by N-Chloro-p-Toluene Sulfonamide in Acid Perchlorate Medium

    International Nuclear Information System (INIS)

    Sailani, Riya; Bhasin, Meneka; Khandelwal, C. L.; Sharma, P. D.

    2014-01-01

    The kinetics and mechanism of oxidation of sulfanilic acid by N-chloro-p-toluene sulfonamide (chloramine-T) have been studied in acid medium. The species of chloramine-T were analysed on the basis of experimental observations and predominantly reactive species was taken into account for proposition of most plausible reaction mechanism. The derived rate law (1) conforms to such a mechanism. All kinetic parameters were evaluated. Activation parameters such as energy and entropy of activation were calculated to be (61.67 ± 0.47) kJ mol -1 and (-62.71 ± 2.48) JK -1 mol -1 respectively employing Eyring equation

  2. Nanocrystalline magnesium oxide: an efficient promoter and heterogeneous nano catalyst for the one-pot synthesis of pyrazolotriazoles in green medium

    Science.gov (United States)

    Naeimi, Hossein; Rashid, Zahra; Zarnani, Amir-Hassan; Ghahremanzadeh, Ramin

    2014-05-01

    A simple, efficient, and relatively clean method for the synthesis of pyrazolo[1,2- a][1,2,4]triazole derivatives via a one-pot three-component reaction of aromatic aldehydes, 4-phenyl-1,2,4-triazolidine-3,5-dione, and malononitrile or alkyl cyanoacetates in the presence of a catalytic amount of nanocrystalline (NC) magnesium oxide has been developed. This method has several advantages such as, high to excellent product yields, reusability of catalyst, and simple work-up procedure in the nontoxic medium.

  3. Construction and modelling of a thermoelectric oxide module (TOM) as a demonstrator - Final report

    Energy Technology Data Exchange (ETDEWEB)

    Tomes, P.; Weidenkaff, A.

    2010-08-15

    The project aims at the development of better thermoelectric materials for the direct conversion of solar heat into electricity. The maximum output power P{sub max} and the efficiency {eta} of the conversion was measured on a series of four-leg thermoelectric oxide modules (TOM). The modules were constructed by combining two p-type (La{sub 1.98}Sr{sub 0.02}CuO{sub 4}) and two n-type (CaMn{sub 0.98}Nb{sub 0.02}O{sub 3}) thermoelements connected electrically in series and thermally in parallel. The temperature gradient {Delta}T was provided by a High-Flux Solar Simulator source (HFSS) which generates a spectrum similar to solar radiation. This project was intended to be a feasibility study for the utilization of high temperature solar heat, which could not previously be demonstrated due to the low temperature stability of conventional materials. The direct conversion was proven by this study. The measurements show an almost linear temperature profile along the thermoelectric legs. However, the maximum output power resulted in 88.8 mW for a TOM with a leg length of 5 mm at {Delta}T = 622 K and has yet to be optimized by improving the converter design and the applied materials. The highest conversion efficiency {eta} was found for a heat flux of 4 to 8 W cm{sup -2}. The dependence of {eta} on the leg length was studied as well as the influence of a graphite coating on the hot Al{sub 2}O{sub 3} surface on {Delta}T, P{sub max} and {eta}. (authors)

  4. Nitric Oxide-Mediated Modulation of Central Network Dynamics during Olfactory Perception.

    Directory of Open Access Journals (Sweden)

    Satoshi Watanabe

    Full Text Available Nitric oxide (NO modulates the dynamics of central olfactory networks and has been implicated in olfactory processing including learning. Land mollusks have a specialized olfactory lobe in the brain called the procerebral (PC lobe. The PC lobe produces ongoing local field potential (LFP oscillation, which is modulated by olfactory stimulation. We hypothesized that NO should be released in the PC lobe in response to olfactory stimulation, and to prove this, we applied an NO electrode to the PC lobe of the land slug Limax in an isolated tentacle-brain preparation. Olfactory stimulation applied to the olfactory epithelium transiently increased the NO concentration in the PC lobe, and this was blocked by the NO synthase inhibitor L-NAME at 3.7 mM. L-NAME at this concentration did not block the ongoing LFP oscillation, but did block the frequency increase during olfactory stimulation. Olfactory stimulation also enhanced spatial synchronicity of activity, and this response was also blocked by L-NAME. Single electrical stimulation of the superior tentacle nerve (STN mimicked the effects of olfactory stimulation on LFP frequency and synchronicity, and both of these effects were blocked by L-NAME. L-NAME did not block synaptic transmission from the STN to the nonbursting (NB-type PC lobe neurons, which presumably produce NO in an activity-dependent manner. Previous behavioral experiments have revealed impairment of olfactory discrimination after L-NAME injection. The recording conditions in the present work likely reproduce the in vivo brain state in those behavioral experiments. We speculate that the dynamical effects of NO released during olfactory perception underlie precise odor representation and memory formation in the brain, presumably through regulation of NB neuron activity.

  5. Astaxanthin mitigates cobalt cytotoxicity in the MG-63 cells by modulating the oxidative stress.

    Science.gov (United States)

    Li, Dahe; Tong, Wenwen; Liu, Denghui; Zou, Yuming; Zhang, Chen; Xu, Weidong

    2017-07-24

    With the re-popularity of metal-on-metal (MoM) bearing in recent years, the cobalt toxicity has been a cause for concern in the total hip replacement surgery by both physicians and patients. MG-63 cell line was cultured in vitro and incubated with cobalt (II) chloride (CoCl 2 ) and/or with astaxanthin (ASX) for 24 h. MTT assay was conducted to evaluate the cell viability after cobalt exposure and ASX treatment. Fluorescence-activated cell sorting (FACS) analysis was performed to examine the reactive oxygen species (ROS) level. Quantitative real-time polymerase chain reaction (PCR) was adopted to determine the mRNA levels of related targets. And western blot analysis was used to examine the protein expressions. One-way ANOVA with posttest Newman-Keuls multiple comparisons was adopted to analysis all the obtained data. In the current study, ASX exhibited significant protective effect against the Co(II)-induced cytotoxicity in MG-63 cell line. We also found that ASX protected the cells against Co-induced apoptosis by regulating the expression of Bcl-2 family proteins. Besides, heme oxygenase 1 (HO-1) could be activated by Co exposure; ASX treatment significantly inhibited HO-1 activation, suppressing the oxidative stress induced by Co exposure. Moreover, c-Jun N-terminal Kinase (JNK) phosphorylation was shown to participate in the signaling pathway of the protective effect of ASX. However, knockdown of JNK expression by siRNA transfection or JNK inhibitor SP600125 treatment did not affect the protective effect of ASX against cobalt cytotoxicity in MG-63 cells. ASX mitigated cobalt cytotoxicity in the MG-63 cells by modulating the oxidative stress. And ASX could be a promising therapy against cobalt toxicity in the hip articulation surgery.

  6. Nitric oxide modulation in protective role of antidepressants against chronic fatigue syndrome in mice.

    Science.gov (United States)

    Kumar, Anil; Garg, Ruchika; Gaur, Vaibhav; Kumar, Puneet

    2011-05-01

    The present study was designed to elucidate the possible nitric oxide (NO) mechanism in the protective effect of antidepressants using mice model of chronic fatigue syndrome (CFS). Male albino laca mice were forced to swim for each 6 min session for 7 days and immobility period was measured on every alternate day (1(st), 3(rd), 5(th), 7(th)). After 7 days various behavioral tests (locomotor, mirror chamber, and plus maze tests for anxiety) were performed and biochemical estimations (lipid peroxidation, nitrite levels, GSH (reduced glutathione), and catalase activity) in mice brain were performed. Animals were pretreated with citalopram (5 and 10 mg/kg) and imipramine (10 and 20 mg/kg) daily for 7 days. The present study showed that continued forced swimming for 7 days caused chronic fatigue-induced anxiety-like behavior as assessed in mirror chamber, plus maze tests, and impairment in locomotor activity followed by oxidative damage (as evidenced by increased lipid peroxidation, nitrite levels, depleted reduced glutathione, and catalase activity) in animals. Seven days pretreatment with citalopram (5 and 10 mg/kg) and imipramine (10 and 20 mg/kg) significantly improved behavioral and biochemical alterations. Further, L-nitro-arginine methyl ester (L-NAME,5 mg/kg) and methylene blue (MB, 10 mg/kg) pretreatment with citalopram (5 mg/kg) or imipramine (10 mg/kg) potentiated their protective effect. However, l-arginine (100 mg/kg) pretreatment with citalopram (5 mg/kg) or imipramine (10 mg/kg) reversed their protective effect as compared with their effect per se (P < 0.05). The present study suggests that protective effect of citalopram and imipramine might be due to its NO modulation against chronic fatigue induced behavioral and biochemical alterations.

  7. Hydrogen peroxide priming modulates abiotic oxidative stress tolerance: insights from ROS detoxification and scavenging

    Directory of Open Access Journals (Sweden)

    Mohammad A. Hossain

    2015-06-01

    Full Text Available Plants are constantly challenged by various abiotic stresses that negatively affect growth and productivity worldwide. During the course of their evolution, plants have developed sophisticated mechanisms to recognize external signals allowing them to respond appropriately to environmental conditions, although the degree of adjustability or tolerance to specific stresses differs from species to species. Overproduction of reactive oxygen species (ROS (hydrogen peroxide, H2O2; superoxide, O2ˉ˙; hydroxyl radical, OH. and singlet oxygen, 1O2 is enhanced under abiotic and/or biotic stresses, which can cause oxidative damage to plant macromolecules and cell structures, leading to inhibition of plant growth and development, or to death. Among the various ROS, freely diffusible and relatively long-lived H2O2 acts as a central player in stress signal transduction pathways. These pathways can then activate multiple acclamatory responses that reinforce resistance to various abiotic and biotic stressors. To utilize H2O2 as a signaling molecule, non-toxic levels must be maintained in a delicate balancing act between H2O2 production and scavenging. Several recent studies have demonstrated that the H2O2-priming can enhance abiotic stress tolerance by modulating ROS detoxification and by regulating multiple stress-responsive pathways and gene expression. Despite the importance of the H2O2-priming, little is known about how this process improves the tolerance of plants to stress. Understanding the mechanisms of H2O2-priming-induced abiotic stress tolerance will be valuable for identifying biotechnological strategies to improve abiotic stress tolerance in crop plants. This review is an overview of our current knowledge of the possible mechanisms associated with H2O2-induced abiotic oxidative stress tolerance in plants, with special reference to antioxidant metabolism.

  8. Hydrogen peroxide priming modulates abiotic oxidative stress tolerance: insights from ROS detoxification and scavenging.

    Science.gov (United States)

    Hossain, Mohammad A; Bhattacharjee, Soumen; Armin, Saed-Moucheshi; Qian, Pingping; Xin, Wang; Li, Hong-Yu; Burritt, David J; Fujita, Masayuki; Tran, Lam-Son P

    2015-01-01

    Plants are constantly challenged by various abiotic stresses that negatively affect growth and productivity worldwide. During the course of their evolution, plants have developed sophisticated mechanisms to recognize external signals allowing them to respond appropriately to environmental conditions, although the degree of adjustability or tolerance to specific stresses differs from species to species. Overproduction of reactive oxygen species (ROS; hydrogen peroxide, H2O2; superoxide, [Formula: see text]; hydroxyl radical, OH(⋅) and singlet oxygen, (1)O2) is enhanced under abiotic and/or biotic stresses, which can cause oxidative damage to plant macromolecules and cell structures, leading to inhibition of plant growth and development, or to death. Among the various ROS, freely diffusible and relatively long-lived H2O2 acts as a central player in stress signal transduction pathways. These pathways can then activate multiple acclamatory responses that reinforce resistance to various abiotic and biotic stressors. To utilize H2O2 as a signaling molecule, non-toxic levels must be maintained in a delicate balancing act between H2O2 production and scavenging. Several recent studies have demonstrated that the H2O2-priming can enhance abiotic stress tolerance by modulating ROS detoxification and by regulating multiple stress-responsive pathways and gene expression. Despite the importance of the H2O2-priming, little is known about how this process improves the tolerance of plants to stress. Understanding the mechanisms of H2O2-priming-induced abiotic stress tolerance will be valuable for identifying biotechnological strategies to improve abiotic stress tolerance in crop plants. This review is an overview of our current knowledge of the possible mechanisms associated with H2O2-induced abiotic oxidative stress tolerance in plants, with special reference to antioxidant metabolism.

  9. The placental cholinergic system: localization to the cytotrophoblast and modulation of nitric oxide

    Directory of Open Access Journals (Sweden)

    Fant Michael E

    2006-05-01

    Full Text Available Abstract Background The human placenta, a non-neuronal tissue, contains an active cholinergic system comprised of acetylcholine (ACh, choline acetyltransferase (ChAT, acetylcholinesterase (AChE, and high affinity muscarinic receptors. The cell(s of origin of placental ACh and its role in trophoblast function has not been defined. These studies were performed to define the cellular location of ACh synthesis (ChAT in the human placenta and to begin studying its functional role. Results Using immunohistochemical techniques, ChAT was observed primarily within the cytotrophoblasts of preterm placentae as well as some mesenchymal elements. Similar intense immunostaining of the cytotrophoblast was observed for endothelium-derived nitric oxide synthase (eNOS suggesting that ACh may interact with nitric oxide (NO-dependent signaling pathways. The ability of carbamylcholine (CCh, an ACh analogue, to stimulate a rise in intracellular Ca++ and NO production in trophoblasts was therefore tested using the BeWob30 choriocarcinoma cell as a model system. First, CCh significantly increased intracellular calcium as assessed by fluorescence microscopy. We then examined the ability of CCh to stimulate NO production by measuring total nitrite/nitrate production in conditioned media using chemiluminescence-based analysis. CCh, alone, had no effect on NO production. However, CCh increased measurable NO approximately 100% in the presence of 10 nM estradiol. This stimulatory effect was inhibited by 1 (microM scopolamine suggesting mediation via muscarinic receptors. Estradiol, alone, had no effect on total NO or eNOS protein or mRNA. Conclusion These data demonstrate that placental ChAT localizes to the cytotrophoblast and some mesenchymal cells in human placenta. It further suggests that ACh acts via muscarinic receptors on the trophoblast cell membrane to modulate NO in an estrogen-dependent manner.

  10. A kinetic and mechanistic study on the oxidation of l-methionine and N-acetyl l-methionine by cerium(IV in sulfuric acid medium

    Directory of Open Access Journals (Sweden)

    T. Sumathi

    2016-09-01

    Full Text Available The kinetics of oxidation of l-methionine and N-acetyl l-methionine by Ce(IV in sulfuric acid–sulfate media in the range of 288.1–298.1 K has been investigated. The major oxidation products of methionine and N-acetyl l-methionine have been identified as methionine sulfoxide and N-acetyl methionine sulfoxide. The major oxidation products have been confirmed by qualitative analysis and boiling point. The reaction was first order with respect to l-methionine, N-acetyl l-methionine and Ce(IV. Increase in [H+], ionic strength and HSO4- did not affect the reaction rate. Under the experimental conditions, Ce4+ was the effective oxidizing species of cerium. Increase in dielectric constant of the medium decreased the reaction rate. Under nitrogen atmosphere, the reaction system can initiate polymerization of acrylonitrile, indicating the generation of free radicals. Activation parameters associated with the overall reaction have been calculated.

  11. Nitric oxide in the nucleus raphe magnus modulates cutaneous blood flow in rats during hypothermia

    Directory of Open Access Journals (Sweden)

    Masoumeh Kourosh Arami

    2015-10-01

    Full Text Available Objective(s: Nucleus Raphe Magnus (NRM that is involved in the regulation of body temperature contains nitric oxide (NO synthase. Considering the effect of NO on skin blood flow control, in this study, we assessed its thermoregulatory role within the raphe magnus. Materials and Methods: To this end, tail blood flow of male Wistar rats was measured by laser doppler following the induction of hypothermia. Results: Intra-NRM injection of SNP (exogenous NO donor, 0.1- 0.2 μl, 0.2 nM increased the blood flow. Similarly, unilateral microinjection of glutamate (0.1- 0.2 μl, 2.3 nM into the nucleus increased the blood flow. This effectof L-glutamate was reduced by prior intra NRM administrationof NO synthase inhibitor NG-methyl-L-arginine or NG-nitro-L-argininemethyl ester (L-NAME, 0.1 µl, 100 nM. Conclusion: It is concluded that NO modulates the thermoregulatory response of NRM to hypothermia and may interactwith excitatory amino acids in central skin blood flow regulation.

  12. Nitric oxide in the nucleus raphe magnus modulates cutaneous blood flow in rats during hypothermia.

    Science.gov (United States)

    Arami, Masoumeh Kourosh; Zade, Javad Mirnajafi; Komaki, Alireza; Amiri, Mahmood; Mehrpooya, Sara; Jahanshahi, Ali; Jamei, Behnam

    2015-10-01

    Nucleus Raphe Magnus (NRM) that is involved in the regulation of body temperature contains nitric oxide (NO) synthase. Considering the effect of NO on skin blood flow control, in this study, we assessed its thermoregulatory role within the raphe magnus. To this end, tail blood flow of male Wistar rats was measured by laser doppler following the induction of hypothermia. Intra-NRM injection of SNP (exogenous NO donor, 0.1- 0.2 μl, 0.2 nM) increased the blood flow. Similarly, unilateral microinjection of glutamate (0.1- 0.2 μl, 2.3 nM) into the nucleus increased the blood flow. This effect of L-glutamate was reduced by prior intra NRM administration of NO synthase inhibitor N(G)-methyl-L-arginine or N(G)-nitro-L-arginine methyl ester (L-NAME, 0.1 µl, 100 nM). It is concluded that NO modulates the thermoregulatory response of NRM to hypothermia and may interact with excitatory amino acids in central skin blood flow regulation.

  13. Synergistic effects between catalase inhibitors and modulators of nitric oxide metabolism on tumor cell apoptosis.

    Science.gov (United States)

    Scheit, Katrin; Bauer, Georg

    2014-10-01

    Inhibitors of catalase (such as ascorbate, methyldopa, salicylic acid and neutralizing antibodies) synergize with modulators of nitric oxide (NO) metabolism (such as arginine, arginase inhibitor, NO synthase-inducing interferons and NO dioxygenase inhibitors) in the singlet oxygen-mediated inactivation of tumor cell protective catalase. This is followed by reactive oxygen species (ROS)-dependent apoptosis induction. TGF-beta, NADPH oxidase-1, NO synthase, dual oxidase-1 and caspase-9 are characterized as essential catalysts in this process. The FAS receptor and caspase-8 are required for amplification of ROS signaling triggered by individual compounds, but are dispensable when the synergistic effect is established. Our findings explain the antitumor effects of catalase inhibitors and of compounds that target NO metabolism, as well as their synergy. These data may have an impact on epidemiological studies related to secondary plant compounds and open new perspectives for the establishment of novel antitumor drugs and for the improvement of established chemotherapeutics. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  14. Nitric oxide modulates the expression of endothelial cell adhesion molecules involved in angiogenesis and leukocyte recruitment.

    Science.gov (United States)

    Carreau, Aude; Kieda, Claudine; Grillon, Catherine

    2011-01-01

    Tumor angiogenesis and immune response have in common to be cell recognition mechanisms, which are based on specific adhesion molecules and dependent on nitric oxide (NO(•)). The aim of the present study is to deepen the mechanisms of angiogenesis and inflammation regulation by NO(•) to find out the molecular regulation processes that govern endothelial cell permeability and leukocyte transmigration. Effects of NO(•), either exogenous or produced in hypoxic conditions, were studied on microvascular endothelial cells from skin and lymph node because of their strong involvement in melanoma progression. We found that NO(•) down-regulation of pseudo-vessel formation was linked to a decrease in endothelial cell ability to adhere to each other which can be explain, in part, by the inhibition of PECAM-1/CD31 expression. On the other hand, NO(•) was shown to be able to decrease leukocyte adhesion on an endothelial monolayer, performed either in static or in rolling conditions, and to modulate differentially CD34, ICAM-1/CD54, ICAM-2/CD102 and VCAM-1/CD106 expression. In conclusion, during angiogenesis and leukocyte recruitment, NO(•) regulates cell interactions by controlling adhesion molecule expression and subsequently cell adhesion. Moreover, each endothelial cell type presents its own organospecific response to NO(•), reflecting the functions of the tissue they originate from. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Exercise Modulates Oxidative Stress and Inflammation in Aging and Cardiovascular Diseases.

    Science.gov (United States)

    Sallam, Nada; Laher, Ismail

    2016-01-01

    Despite the wealth of epidemiological and experimental studies indicating the protective role of regular physical activity/exercise training against the sequels of aging and cardiovascular diseases, the molecular transducers of exercise/physical activity benefits are not fully identified but should be further investigated in more integrative and innovative approaches, as they bear the potential for transformative discoveries of novel therapeutic targets. As aging and cardiovascular diseases are associated with a chronic state of oxidative stress and inflammation mediated via complex and interconnected pathways, we will focus in this review on the antioxidant and anti-inflammatory actions of exercise, mainly exerted on adipose tissue, skeletal muscles, immune system, and cardiovascular system by modulating anti-inflammatory/proinflammatory cytokines profile, redox-sensitive transcription factors such as nuclear factor kappa B, activator protein-1, and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, antioxidant and prooxidant enzymes, and repair proteins such as heat shock proteins, proteasome complex, oxoguanine DNA glycosylase, uracil DNA glycosylase, and telomerase. It is important to note that the effects of exercise vary depending on the type, intensity, frequency, and duration of exercise as well as on the individual's characteristics; therefore, the development of personalized exercise programs is essential.

  16. Exercise Modulates Oxidative Stress and Inflammation in Aging and Cardiovascular Diseases

    Directory of Open Access Journals (Sweden)

    Nada Sallam

    2016-01-01

    Full Text Available Despite the wealth of epidemiological and experimental studies indicating the protective role of regular physical activity/exercise training against the sequels of aging and cardiovascular diseases, the molecular transducers of exercise/physical activity benefits are not fully identified but should be further investigated in more integrative and innovative approaches, as they bear the potential for transformative discoveries of novel therapeutic targets. As aging and cardiovascular diseases are associated with a chronic state of oxidative stress and inflammation mediated via complex and interconnected pathways, we will focus in this review on the antioxidant and anti-inflammatory actions of exercise, mainly exerted on adipose tissue, skeletal muscles, immune system, and cardiovascular system by modulating anti-inflammatory/proinflammatory cytokines profile, redox-sensitive transcription factors such as nuclear factor kappa B, activator protein-1, and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, antioxidant and prooxidant enzymes, and repair proteins such as heat shock proteins, proteasome complex, oxoguanine DNA glycosylase, uracil DNA glycosylase, and telomerase. It is important to note that the effects of exercise vary depending on the type, intensity, frequency, and duration of exercise as well as on the individual’s characteristics; therefore, the development of personalized exercise programs is essential.

  17. Nitric Oxide Isotopic Analyzer Based on a Compact Dual-Modulation Faraday Rotation Spectrometer

    Directory of Open Access Journals (Sweden)

    Eric Zhang

    2015-10-01

    Full Text Available We have developed a transportable spectroscopic nitrogen isotopic analyzer. The spectrometer is based on dual-modulation Faraday rotation spectroscopy of nitric oxide isotopologues with near shot-noise limited performance and baseline-free operation. Noise analysis indicates minor isotope (15NO detection sensitivity of 0.36 ppbv·Hz−1/2, corresponding to noise-equivalent Faraday rotation angle (NEA of 1.31 × 10−8 rad·Hz−1/2 and noise-equivalent absorbance (αLmin of 6.27 × 10−8 Hz−1/2. White-noise limited performance at 2.8× the shot-noise limit is observed up to ~1000 s, allowing reliable calibration and sample measurement within the drift-free interval of the spectrometer. Integration with wet-chemistry based on acidic vanadium(III enables conversion of aqueous nitrate/nitrite samples to gaseous NO for total nitrogen isotope analysis. Isotopic ratiometry is accomplished via time-multiplexed measurements of two NO isotope transitions. For 5 μmol potassium nitrate samples, the instrument consistently yields ratiometric precision below 0.3‰, thus demonstrating potential as an in situ diagnostic tool for environmental nitrogen cycle studies.

  18. Nitric Oxide Isotopic Analyzer Based on a Compact Dual-Modulation Faraday Rotation Spectrometer

    Science.gov (United States)

    Zhang, Eric; Huang, Stacey; Ji, Qixing; Silvernagel, Michael; Wang, Yin; Ward, Bess; Sigman, Daniel; Wysocki, Gerard

    2015-01-01

    We have developed a transportable spectroscopic nitrogen isotopic analyzer. The spectrometer is based on dual-modulation Faraday rotation spectroscopy of nitric oxide isotopologues with near shot-noise limited performance and baseline-free operation. Noise analysis indicates minor isotope (15NO) detection sensitivity of 0.36 ppbv·Hz−1/2, corresponding to noise-equivalent Faraday rotation angle (NEA) of 1.31 × 10−8 rad·Hz−1/2 and noise-equivalent absorbance (αL)min of 6.27 × 10−8 Hz−1/2. White-noise limited performance at 2.8× the shot-noise limit is observed up to ~1000 s, allowing reliable calibration and sample measurement within the drift-free interval of the spectrometer. Integration with wet-chemistry based on acidic vanadium(III) enables conversion of aqueous nitrate/nitrite samples to gaseous NO for total nitrogen isotope analysis. Isotopic ratiometry is accomplished via time-multiplexed measurements of two NO isotope transitions. For 5 μmol potassium nitrate samples, the instrument consistently yields ratiometric precision below 0.3‰, thus demonstrating potential as an in situ diagnostic tool for environmental nitrogen cycle studies. PMID:26473876

  19. Does the MRI or MRI contrast medium gadopentetate dimeglumine change the oxidant and antioxidant status in humans?

    International Nuclear Information System (INIS)

    Olmaz, Refik; Oguz, Ebru Gok; Kiykim, Ahmet; Turgutalp, Kenan; Horoz, M.; Ozhan, Onur; Muslu, Necati; Sungur, Mehmet

    2013-01-01

    Background: It has become evident that gadolinium-based contrast agents (GBCA) may have nephrotoxic potential. Oxidative stress is one of the most important pathways in the pathogenesis of iodinated contrast-induced nephropathy. Purpose: To investigate the effects of static magnetic fields and gadopentetate dimeglumine (Magnevist) on oxidant/antioxidant status via measurement of total antioxidant capacity (TAC), total oxidant status (TOS), and serum malondialdehide (MDA). Material and Methods: Two age- and sex-matched groups of patients not under oxidative stress conditions that underwent magnetic resonance imaging (MRI) were recruited to this study. While contrast-enhanced (Magnevist, 0.2 mmol/kg) MRI was performed in group 1, MRI without GBCA was performed in group 2. Fasting blood glucose, C-reactive protein, serum creatinine, liver enzymes, uric acid, and lipid parameters were examined in all patients. Peripheral venous blood samples in order to determine TAC, TOS, and MDA were collected before and 6, 24, and 72 h after the MRI procedures. The TOS:TAC ratio was used as the oxidative stress index (OSI). Patients were followed up to 72 h. Results: There were no significant changes in serum TAC, TOS, and MDA levels (Δ s erum T AC, Δ s erum T OS, and Δ M DA) in either group 6, 24, or 72 h after the procedures (P > 0.05). Furthermore, OSI did not change after the procedures in either group (P > 0.05). Conclusion: Magnetic field and gadopentetate dimeglumine (Magnevist) do not change the oxidant or antioxidant status at a dose of 0.2 mmol/kg

  20. Does the MRI or MRI contrast medium gadopentetate dimeglumine change the oxidant and antioxidant status in humans?

    Energy Technology Data Exchange (ETDEWEB)

    Olmaz, Refik; Oguz, Ebru Gok; Kiykim, Ahmet; Turgutalp, Kenan [Dept. of Internal Medicine, Div. of Nephrology, School of Medicine, Mersin Univ., Mersin (Turkey)], e-mail: k.turgutalp@hotmail.com; Horoz, M. [Dept. of Internal Medicine, Div. of Nephrology, School of Medicine, Harran Univ., Sanliurfa (Turkey); Ozhan, Onur [Dept. of Internal Medicine, Div. of Endocrinology and Metabolism, School of Medicine, Mersin Univ., Mersin (Turkey); Muslu, Necati [Dept. of Biochemistry, School of Medicine, Mersin Univ., Mersin (Turkey); Sungur, Mehmet [Dept. of Biostatistics, School of Medicine, Mersin Univ., Mersin (Turkey)

    2013-02-15

    Background: It has become evident that gadolinium-based contrast agents (GBCA) may have nephrotoxic potential. Oxidative stress is one of the most important pathways in the pathogenesis of iodinated contrast-induced nephropathy. Purpose: To investigate the effects of static magnetic fields and gadopentetate dimeglumine (Magnevist) on oxidant/antioxidant status via measurement of total antioxidant capacity (TAC), total oxidant status (TOS), and serum malondialdehide (MDA). Material and Methods: Two age- and sex-matched groups of patients not under oxidative stress conditions that underwent magnetic resonance imaging (MRI) were recruited to this study. While contrast-enhanced (Magnevist, 0.2 mmol/kg) MRI was performed in group 1, MRI without GBCA was performed in group 2. Fasting blood glucose, C-reactive protein, serum creatinine, liver enzymes, uric acid, and lipid parameters were examined in all patients. Peripheral venous blood samples in order to determine TAC, TOS, and MDA were collected before and 6, 24, and 72 h after the MRI procedures. The TOS:TAC ratio was used as the oxidative stress index (OSI). Patients were followed up to 72 h. Results: There were no significant changes in serum TAC, TOS, and MDA levels ({Delta}{sub s}erum{sub T}AC, {Delta}{sub s}erum{sub T}OS, and {Delta}{sub M}DA) in either group 6, 24, or 72 h after the procedures (P > 0.05). Furthermore, OSI did not change after the procedures in either group (P > 0.05). Conclusion: Magnetic field and gadopentetate dimeglumine (Magnevist) do not change the oxidant or antioxidant status at a dose of 0.2 mmol/kg.

  1. Supported 3-D Pt nanostructures: the straightforward synthesis and enhanced electrochemical performance for methanol oxidation in an acidic medium

    International Nuclear Information System (INIS)

    Li, Zesheng; Ji, Shan; Pollet, Bruno G.; Shen, Pei Kang

    2013-01-01

    Noble metal nanostructures with branched morphologies [i.e., 3-D Pt nanoflowers (NFs)] by tri-dimensionally integrating onto conductive carbon materials are proved to be an efficient and durable electrocatalysts for methanol oxidation. The well-supported 3-D Pt NFs are readily achieved by an efficient cobalt-induced/carbon-mediated galvanic reaction approach. Due to the favorable nanostructures (3-D Pt configuration allowing a facile mass transfer) and supporting effects (including framework stabilization, spatially separate feature, and improved charge transport effects), these 3-D Pt NFs manifest much higher electrocatalytic activity and stability toward methanol oxidation than that of the commercial Pt/C and Pt-based electrocatalysts

  2. Increasing the Carbon Flux toward Synthesis of Short-Chain-Length-Medium-Chain-Length Polyhydroxyalkanoate in the Peroxisome of Saccharomyces cerevisiae through Modification of the β-Oxidation Cycle

    OpenAIRE

    de Oliveira, Valeria Cora; Maeda, Isamu; Delessert, Syndie; Poirier, Yves

    2004-01-01

    Short-chain-length-medium-chain-length polyhydroxyalkanoates were synthesized in Saccharomyces cerevisiae from intermediates of the β-oxidation cycle by expressing the polyhydroxyalkanoate synthases from Aeromonas caviae and Ralstonia eutropha in the peroxisomes. The quantity of polymer produced was increased by using a mutant of the β-oxidation-associated multifunctional enzyme with low dehydrogenase activity toward R-3-hydroxybutyryl coenzyme A.

  3. Role of Ru(IlI) as an inhibitor in oxidation of lactose by (Cu(bipy)2)2+ in alkaline medium: spectrophotometric and kinetic studies

    International Nuclear Information System (INIS)

    Singh, Ashok Kumar; Singh, Manjula; Srivastava, Jaya; Rahmani, Shahla

    2013-01-01

    Kinetics of oxidation of lactose by (Cu(bipy) 2 ) 2+ in alkaline medium using Ru(III) as an inhibitor has been studied spectrophotometrically at 40 °C. The studies show that the rate of the reaction is zero order with respect to (Cu(bipy) 2 ) 2+ and first order with respect to (lactose). The order of reaction is found to be two at low concentrations of OH - (from 1.48×10 5 to 3.47×10 5 M) and less than two at its high concentrations (from 4.27×10 5 to 6.31×10 5 M). There is a substantial decrease in the pseudo-zero order rate constant with increase in the concentration of Ru(III) chloride, indicating the role of Ru(III) chloride as an inhibitor. Decrease in the rate with increase in dielectric constant of the medium is observed, while ionic strength of the medium and bipyridyl concentration has no influence on the rate. Based on kinetic data and spectrophotometric evidences, a suitable mechanism is proposed for the studied reaction. (author)

  4. Plasma-stimulated medium kills TRAIL-resistant human malignant cells by promoting caspase-independent cell death via membrane potential and calcium dynamics modulation.

    Science.gov (United States)

    Tokunaga, Tomohiko; Ando, Takashi; Suzuki-Karasaki, Miki; Ito, Tomohisa; Onoe-Takahashi, Asuka; Ochiai, Toyoko; Soma, Masayoshi; Suzuki-Karasaki, Yoshihiro

    2018-03-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and cold plasma-stimulated medium (PSM) have been shown to exhibit tumor-selective cytotoxicity and have emerged as promising new tools for cancer treatment. However, to date, at least to the best of our knowledge, no data are available as to which substance is more potent in killing cancer cells. Thus, in this study, we systematically compared their abilities to kill human malignant cells from different origins. We found that PSM dose-dependently killed TRAIL-resistant melanoma, osteosarcoma and neuroblastoma cells. Moreover, PSM had little cytotoxicity toward osteoblasts. PSM was more potent than TRAIL in inducing caspase-3/7 activation, mitochondrial network aberration and caspase-independent cell death. We also found that PSM was more potent in inducing plasma membrane depolarization (PMD) and disrupting endoplasmic-mitochondrial Ca2+ homeostasis. Moreover, persistent PMD was caused by different membrane-depolarizing agents; the use of the anti-type II diabetes drug, glibenclamide, alone caused mitochondrial fragmentation and enhanced TRAIL-induced Ca2+ modulation, mitochondrial network abnormalities and caspase-independent cell killing. These results demonstrate that PSM has a therapeutic advantage over TRAIL owing to its greater capacity to evoke caspase-independent cell death via mitochondrial network aberration by disrupting membrane potential and Ca2+ homeostasis. These findings may provide a strong rationale for developing PSM as a novel approach for the treatment of TRAIL-resistant malignant cells.

  5. Effect of ionic micellar medium on kinetics and mechanism of oxidation of bovine serum albumin: A pulse radiolysis study

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, Ravi, E-mail: rjudrin@yahoo.co [Radiation and Photochemistry Division, Chemistry Group, Bhabha Atomic Research Center, Mumbai 400085 (India); Mukherjee, Tulsi [Radiation and Photochemistry Division, Chemistry Group, Bhabha Atomic Research Center, Mumbai 400085 (India)

    2010-09-15

    Effect of protein-micelle interaction on bovine serum albumin (BSA) oxidation by trichloromethyl peroxyl radical (CCl{sub 3}O{sub 2}{sup .}) in anionic sodium dodecyl sulfate (SDS) and cationic cetyltrimethyl ammonium bromide (CTAB) micellar media has been studied using nanosecond pulse radiolysis technique. Viscosity measurement and light scattering studies have suggested that SDS and CTAB micelles produce BSA-micelle aggregates of different sizes and polydispersity. Oxidation kinetics and transients have been affected both by anionic SDS and cationic CTAB micelles but in a different manner. Tryptophanyl-CCl{sub 3}O{sub 2}{sup .} adduct radical to tyrosyl radical transformation in BSA has been observed in anionic SDS micelles but not in cationic CTAB micelles. Similar studies have also been done with tryptophan and tyrosine amino acids, which undergo oxidation in BSA. The study suggests that Coulombic and hydrophobic interactions between micelles and protein affect the structure of the protein to shield its functional amino acids, like tryptophan and tyrosine, to neutral oxidizing radical.

  6. Modulating nitric oxide levels in dorsal root ganglion neurons of rat with low-level laser therapy

    Science.gov (United States)

    Zheng, Li-qin; Wang, Yu-hua; He, Yi-peng; Zhou, Jie; Yang, Hong-qin; Zhang, Yan-ding; Xie, Shu-sen

    2015-05-01

    Nitric oxide (NO) and nitric oxide synthase (NOS) have an important role in pain signaling transmission in animal models. Low-level laser therapy (LLLT) is known to have an analgesic effect, but the mechanism is unclear. The aim of the study is to investigate the influence of LLLT on NO release and NOS synthesis in dorsal root ganglion (DRG) neurons, in order to find whether LLLI can ameliorate pain through modulating NO production at the cellular level. The results show that in stress conditions, the laser irradiation at 658 nm can modulate NO production in DRG neurons with soma diameter of about 20 μm in a short time after illumination, and affect NOS synthesis in a dose-dependent manner. It is demonstrated that LLLT might treat pain by altering NO release directly and indirectly in DRG neurons.

  7. Cooling rate and size effects on the medium-range structure of multicomponent oxide glasses simulated by molecular dynamics

    International Nuclear Information System (INIS)

    Tilocca, Antonio

    2013-01-01

    A set of molecular dynamics simulations were performed to investigate the effect of cooling rate and system size on the medium-range structure of melt-derived multicomponent silicate glasses, represented by the quaternary 45S5 Bioglass composition. Given the significant impact of the glass degradation on applications of these materials in biomedicine and nuclear waste disposal, bulk structural features which directly affect the glass dissolution process are of particular interest. Connectivity of the silicate matrix, ion clustering and nanosegregation, distribution of ring and chain structural patterns represent critical features in this context, which can be directly extracted from the models. A key issue is represented by the effect of the computational approach on the corresponding glass models, especially in light of recent indications questioning the suitability of conventional MD approaches (that is, involving melt-and-quench of systems containing ∼10 3 atoms at cooling rates of 5-10 K/ps) when applied to model these glasses. The analysis presented here compares MD models obtained with conventional and nonconventional cooling rates and system sizes, highlighting the trend and range of convergence of specific structural features in the medium range. The present results show that time-consuming computational approaches involving much lower cooling rates and/or significantly larger system sizes are in most cases not necessary in order to obtain a reliable description of the medium-range structure of multicomponent glasses. We identify the convergence range for specific properties and use them to discuss models of several glass compositions for which a possible influence of cooling-rate or size effects had been previously hypothesized. The trends highlighted here represent an important reference to obtain reliable models of multicomponent glasses and extract converged medium-range structural features which affect the glass degradation and thus their application

  8. Temperature Modulation with Specified Detection Point on Metal Oxide Semiconductor Gas Sensors for E-Nose Application

    Directory of Open Access Journals (Sweden)

    Arief SUDARMAJI

    2015-03-01

    Full Text Available Temperature modulation technique, some called dynamic measurement mode, on Metal-Oxide Semiconductor (MOS/MOX gas sensor has been widely observed and employed in many fields. We present its development, a Specified Detection Point (SDP on modulated sensing element of MOS sensor is applied which associated to its temperature modulation, temperature modulation-SDP so-named. We configured the rectangular modulation signal for MOS gas sensors (TGSs and FISs using PSOC CY8C28445-24PVXI (Programmable System on Chip which also functioned as acquisition unit and interface to a computer. Initial responses and selectivity evaluations were performed using statistical tool and Principal Component Analysis (PCA to differ sample gases (Toluene, Ethanol and Ammonia on dynamic chamber measurement under various frequencies (0.25 Hz, 1 Hz, 4 Hz and duty-cycles (25 %, 50 %, 75 %. We found that at lower frequency the response waveform of the sensors becomes more sloping and distinct, and selected modulations successfully increased the selectivity either on singular or array sensors rather than static temperature measurement.

  9. Copper(II catalysis for oxidation of l-tryptophan by hexacyanoferrate(III in alkaline medium: A kinetic and mechanistic approach

    Directory of Open Access Journals (Sweden)

    Basim H. Asghar

    2017-12-01

    Full Text Available The catalytic effect of copper(II catalyst on the oxidation of l-tryptophan (Trp by hexacyanoferrate(III (HCF, has been investigated spectrophotometrically in an aqueous alkaline medium at a constant ionic strength of 0.5 mol dm−3 and at 25 °C. The stoichiometry for both the uncatalyzed and catalyzed reactions was 1:2 (Trp:HCF. The reactions exhibited first order kinetics with respect to [HCF] and less than unit orders with respect to [Trp] and [OH−]. The catalyzed reaction exhibited fractional-first order kinetics with respect to [CuII]. The reaction rates were found to increase as the ionic strength and dielectric constant of the reaction medium increase. The effect of temperature on the rates of reactions has also been studied, and the activation parameters associated with the rate-determining steps of the reactions have been evaluated and discussed. Addition of the reaction product HCF(II to the reaction mixture did not affect the rates. Plausible mechanistic schemes for uncatalyzed and catalyzed reactions explaining all of the observed kinetic results have been proposed. In both cases, the final oxidation products are identified as indole-3-acetaldehyde, ammonia, and carbon dioxide. The rate laws associated with the reactions’ mechanisms are derived. The rate constants of the slow steps of the reactions along with the equilibrium constants are also calculated. Keywords: Oxidation, Kinetics, l-Tryptophan, Hexacyanoferrate(III, Copper(II, Catalysis

  10. Caffeic acid, a phenol found in white wine, modulates endothelial nitric oxide production and protects from oxidative stress-associated endothelial cell injury.

    Directory of Open Access Journals (Sweden)

    Massimiliano Migliori

    Full Text Available Several studies demonstrated that endothelium dependent vasodilatation is impaired in cardiovascular and chronic kidney diseases because of oxidant stress-induced nitric oxide availability reduction. The Mediterranean diet, which is characterized by food containing phenols, was correlated with a reduced incidence of cardiovascular diseases and delayed progression toward end stage chronic renal failure. Previous studies demonstrated that both red and white wine exert cardioprotective effects. In particular, wine contains Caffeic acid (CAF, an active component with known antioxidant activities.The aim of the present study was to investigate the protective effect of low doses of CAF on oxidative stress-induced endothelial injury.CAF increased basal as well as acetylcholine-induced NO release by a mechanism independent from eNOS expression and phosphorylation. In addition, low doses of CAF (100 nM and 1 μM increased proliferation and angiogenesis and inhibited leukocyte adhesion and endothelial cell apoptosis induced by hypoxia or by the uremic toxins ADMA, p-cresyl sulfate and indoxyl sulfate. The biological effects exerted by CAF on endothelial cells may be at least in part ascribed to modulation of NO release and by decreased ROS production. In an experimental model of kidney ischemia-reperfusion injury in mice, CAF significantly decreased tubular cell apoptosis, intraluminal cast deposition and leukocyte infiltration.The results of the present study suggest that CAF, at very low dosages similar to those observed after moderate white wine consumption, may exert a protective effect on endothelial cell function by modulating NO release independently from eNOS expression and phosphorylation. CAF-induced NO modulation may limit cardiovascular and kidney disease progression associated with oxidative stress-mediated endothelial injury.

  11. Caffeic acid, a phenol found in white wine, modulates endothelial nitric oxide production and protects from oxidative stress-associated endothelial cell injury.

    Science.gov (United States)

    Migliori, Massimiliano; Cantaluppi, Vincenzo; Mannari, Claudio; Bertelli, Alberto A E; Medica, Davide; Quercia, Alessandro Domenico; Navarro, Victor; Scatena, Alessia; Giovannini, Luca; Biancone, Luigi; Panichi, Vincenzo

    2015-01-01

    Several studies demonstrated that endothelium dependent vasodilatation is impaired in cardiovascular and chronic kidney diseases because of oxidant stress-induced nitric oxide availability reduction. The Mediterranean diet, which is characterized by food containing phenols, was correlated with a reduced incidence of cardiovascular diseases and delayed progression toward end stage chronic renal failure. Previous studies demonstrated that both red and white wine exert cardioprotective effects. In particular, wine contains Caffeic acid (CAF), an active component with known antioxidant activities. The aim of the present study was to investigate the protective effect of low doses of CAF on oxidative stress-induced endothelial injury. CAF increased basal as well as acetylcholine-induced NO release by a mechanism independent from eNOS expression and phosphorylation. In addition, low doses of CAF (100 nM and 1 μM) increased proliferation and angiogenesis and inhibited leukocyte adhesion and endothelial cell apoptosis induced by hypoxia or by the uremic toxins ADMA, p-cresyl sulfate and indoxyl sulfate. The biological effects exerted by CAF on endothelial cells may be at least in part ascribed to modulation of NO release and by decreased ROS production. In an experimental model of kidney ischemia-reperfusion injury in mice, CAF significantly decreased tubular cell apoptosis, intraluminal cast deposition and leukocyte infiltration. The results of the present study suggest that CAF, at very low dosages similar to those observed after moderate white wine consumption, may exert a protective effect on endothelial cell function by modulating NO release independently from eNOS expression and phosphorylation. CAF-induced NO modulation may limit cardiovascular and kidney disease progression associated with oxidative stress-mediated endothelial injury.

  12. Durability of carbon-supported manganese oxide nanoparticles for the oxygen reduction reaction (ORR) in alkaline medium

    Czech Academy of Sciences Publication Activity Database

    Roche, I.; Chainet, E.; Chatenet, M.; Vondrák, Jiří

    2008-01-01

    Roč. 38, č. 9 (2008), s. 1195-1201 ISSN 0021-891X R&D Projects: GA AV ČR KJB4813302; GA ČR GA104/02/0731 Grant - others:CNRS(FR) 18105 Institutional research plan: CEZ:AV0Z40320502 Keywords : oxygen reduction reaction * rotating ring-disc electrode * carbon-supported manganese oxide Subject RIV: CA - Inorganic Chemistry Impact factor: 1.540, year: 2008

  13. Morin Attenuates Ovalbumin-Induced Airway Inflammation by Modulating Oxidative Stress-Responsive MAPK Signaling

    Directory of Open Access Journals (Sweden)

    Yuan Ma

    2016-01-01

    Full Text Available Asthma is one of the most common inflammatory diseases characterized by airway hyperresponsiveness, inflammation, and remodeling. Morin, an active ingredient obtained from Moraceae plants, has been demonstrated to have promising anti-inflammatory activities in a range of disorders. However, its impacts on pulmonary diseases, particularly on asthma, have not been clarified. This study was designed to investigate whether morin alleviates airway inflammation in chronic asthma with an emphasis on oxidative stress modulation. In vivo, ovalbumin- (OVA- sensitized mice were administered with morin or dexamethasone before challenge. Bronchoalveolar lavage fluid (BALF and lung tissues were obtained to perform cell counts, histological analysis, and enzyme-linked immunosorbent assay. In vitro, human bronchial epithelial cells (BECs were challenged by tumor necrosis factor alpha (TNF-α. The supernatant was collected for the detection of the proinflammatory proteins, and the cells were collected for reactive oxygen species (ROS/mitogen-activated protein kinase (MAPK evaluations. Severe inflammatory responses and remodeling were observed in the airways of the OVA-sensitized mice. Treatment with morin dramatically attenuated the extensive trafficking of inflammatory cells into the BALF and inhibited their infiltration around the respiratory tracts and vessels. Morin administration also significantly suppressed goblet cell hyperplasia and collagen deposition/fibrosis and dose-dependently inhibited the OVA-induced increases in IgE, TNF-α, interleukin- (IL- 4, IL-13, matrix metalloproteinase-9, and malondialdehyde. In human BECs challenged by TNF-α, the levels of proteins such as eotaxin-1, monocyte chemoattractant protein-1, IL-8 and intercellular adhesion molecule-1, were consistently significantly decreased by morin. Western blotting and the 2′,7′-dichlorofluorescein assay revealed that the increases in intracellular ROS and MAPK phosphorylation were

  14. Ethanol electro-oxidation in alkaline medium using Pd/MWCNT and PdAuSn/MWCNT electrocatalysts prepared by electron beam irradiation

    International Nuclear Information System (INIS)

    Geraldes, Adriana Napoleao; Silva, Dionisio Furtunato da; Andrade e Silva, Leonardo Gondin de; Spinace, Estevam Vitorio; Oliveira Neto, Almir; Santos, Mauro Coelho dos

    2015-01-01

    Environmental problems and the world growing demand for energy has mobilized the scientific community in finding of clean and renewable energy sources. In this context, fuel cells appear as appropriate technology for generating electricity through alcohols electro-oxidation. Multi Wall Carbon Nanotubes (MWCNT)-supported Pd and trimetallic PdAuSn (Pd:Au:Sn 50:10:40 atomic ratio) electrocatalysts were prepared using electron beam irradiation. The obtained materials were characterized by VC, Chronoamperometry, EDX, TEM and XRD. The catalytic activities of electrocatalysts toward ethanol electro-oxidation were evaluated in alkaline medium in a single alkaline direct ethanol fuel cell (ADEFC) in a range temperature 60 to 90 deg C. The best performances were obtained at 85 deg C: 33 mW.cm -2 and 31 mW.cm -2 for Pd/ MWCNT and PdAuSn/MWCNT electrocatalysts, respectively. X-ray diffractograms of electrocatalysts showed the presence of Pd-rich (fcc) and Au-rich (fcc) phases. Cyclic voltammetry and chronoamperometry experiments showed that PdAuSn/MWCNT electrocatalyst demonstrated similar activity toward ethanol electro-oxidation at room temperature, compared to electrocatalyst Pd/MWCNT. (author)

  15. Adrenalectomy alters regulation of blood pressure and endothelial nitric oxide synthase in sheep: modulation by estradiol.

    Science.gov (United States)

    Li, Feng; Wood, Charles E; Keller-Wood, Maureen

    2007-07-01

    Hypoadrenocorticism produces more severe hypotension during the peripartal period in pregnant ewes and women. We hypothesized that estradiol increases the severity of hypotension after withdrawal of corticosteroids and that this results from combined effects of adrenalectomy and estradiol to increase endothelial nitric oxide synthase (eNOS). In study I, blood pressure and eNOS mRNA and protein in aorta, uterine, renal, and mesenteric arteries were measured in intact ewes or adrenalectomized ewes 18-20 h after cessation of infusion of cortisol and aldosterone; half of each group ewes were treated with estradiol. In study II, adrenalectomized ewes were similarly studied 22-28 h after withdrawal of corticosteroids. Estradiol treatment in both studies significantly increased eNOS mRNA and protein in uterine artery, whereas corticosteroid withdrawal decreased expression of eNOS mRNA and protein in uterine artery. In both studies, adrenalectomy and steroid withdrawal decreased mean arterial pressure. In study II, four of six adrenalectomized ewes not treated with estradiol showed dramatic phasic variations in blood pressure and heart rate with a period of approximately 20 s, developing within 22-28 h after corticosteroid withdrawal. Although there was no effect of estradiol on blood pressure in study I, in study II, ewes treated with estradiol did not develop this pattern. Estradiol also slowed both the decline in plasma sodium and the rise in plasma potassium after corticosteroid withdrawal. These results disprove the hypothesis that estradiol increases the severity of hypotension during hypoadrenocorticism. However, the study reveals an important effect of corticosteroid withdrawal on blood pressure, consistent with corticosteroid modulation of baroreflex responsiveness.

  16. Low Power Operation of Temperature-Modulated Metal Oxide Semiconductor Gas Sensors.

    Science.gov (United States)

    Burgués, Javier; Marco, Santiago

    2018-01-25

    Mobile applications based on gas sensing present new opportunities for low-cost air quality monitoring, safety, and healthcare. Metal oxide semiconductor (MOX) gas sensors represent the most prominent technology for integration into portable devices, such as smartphones and wearables. Traditionally, MOX sensors have been continuously powered to increase the stability of the sensing layer. However, continuous power is not feasible in many battery-operated applications due to power consumption limitations or the intended intermittent device operation. This work benchmarks two low-power, duty-cycling, and on-demand modes against the continuous power one. The duty-cycling mode periodically turns the sensors on and off and represents a trade-off between power consumption and stability. On-demand operation achieves the lowest power consumption by powering the sensors only while taking a measurement. Twelve thermally modulated SB-500-12 (FIS Inc. Jacksonville, FL, USA) sensors were exposed to low concentrations of carbon monoxide (0-9 ppm) with environmental conditions, such as ambient humidity (15-75% relative humidity) and temperature (21-27 °C), varying within the indicated ranges. Partial Least Squares (PLS) models were built using calibration data, and the prediction error in external validation samples was evaluated during the two weeks following calibration. We found that on-demand operation produced a deformation of the sensor conductance patterns, which led to an increase in the prediction error by almost a factor of 5 as compared to continuous operation (2.2 versus 0.45 ppm). Applying a 10% duty-cycling operation of 10-min periods reduced this prediction error to a factor of 2 (0.9 versus 0.45 ppm). The proposed duty-cycling powering scheme saved up to 90% energy as compared to the continuous operating mode. This low-power mode may be advantageous for applications that do not require continuous and periodic measurements, and which can tolerate slightly higher

  17. Wavelet entropy of Doppler ultrasound blood velocity flow waveforms distinguishes nitric oxide-modulated states.

    Science.gov (United States)

    Agnew, Christina E; Hamilton, Paul K; McCann, Aaron J; McGivern, R Canice; McVeigh, Gary E

    2015-05-01

    Wavelet entropy assesses the degree of order or disorder in signals and presents this complex information in a simple metric. Relative wavelet entropy assesses the similarity between the spectral distributions of two signals, again in a simple metric. Wavelet entropy is therefore potentially a very attractive tool for waveform analysis. The ability of this method to track the effects of pharmacologic modulation of vascular function on Doppler blood velocity waveforms was assessed. Waveforms were captured from ophthalmic arteries of 10 healthy subjects at baseline, after the administration of glyceryl trinitrate (GTN) and after two doses of N(G)-nitro-L-arginine-methyl ester (L-NAME) to produce vasodilation and vasoconstriction, respectively. Wavelet entropy had a tendency to decrease from baseline in response to GTN, but significantly increased after the administration of L-NAME (mean: 1.60 ± 0.07 after 0.25 mg/kg and 1.72 ± 0.13 after 0.5 mg/kg vs. 1.50 ± 0.10 at baseline, p wavelet entropy had a spectral distribution from increasing doses of L-NAME comparable to baseline, 0.07 ± 0.04 and 0.08 ± 0.03, respectively, whereas GTN had the most dissimilar spectral distribution compared with baseline (0.17 ± 0.08, p = 0.002). Wavelet entropy can detect subtle changes in Doppler blood velocity waveform structure in response to nitric-oxide-mediated changes in arteriolar smooth muscle tone. Copyright © 2015 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  18. Response of cardiac endothelial nitric oxide synthase to plasma viscosity modulation in acute isovolemic hemodilution

    Directory of Open Access Journals (Sweden)

    Kanyanatt Kanokwiroon

    2014-01-01

    Full Text Available Background: Endothelial nitric oxide synthase (eNOS is generally expressed in endocardial cells, vascular endothelial cells and ventricular myocytes. However, there is no experimental study elucidating the relationship between cardiac eNOS expression and elevated plasma viscosity in low oxygen delivery pathological conditions such as hemorrhagic shock-resuscitation and hemodilution. This study tested the hypothesis that elevated plasma viscosity increases cardiac eNOS expression in a hemodilution model, leading to positive effects on cardiac performance. Materials and Methods: Two groups of golden Syrian hamster underwent an acute isovolemic hemodilution where 40% of blood volume was exchanged with 2% (low-viscogenic plasma expander [LVPE] or 6% (high-viscogenic plasma expander [HVPE] of dextran 2000 kDa. In control group, experiment was performed without hemodilution. All groups were performed in awake condition. Experimental parameters, i.e., mean arterial blood pressure (MAP, heart rate, hematocrit, blood gas content and viscosity, were measured. The eNOS expression was evaluated by eNOS Western blot analysis. Results: After hemodilution, MAP decreased to 72% and 93% of baseline in the LVPE and HVPE, respectively. Furthermore, pO 2 in the LVPE group increased highest among the groups. Plasma viscosity in the HVPE group was significantly higher than that in control and LVPE groups. The expression of eNOS in the HVPE group showed higher intensity compared to other groups, especially compared with the control group. Conclusion: Our results demonstrated that cardiac eNOS has responded to plasma viscosity modulation with HVPE and LVPE. This particularly supports the previous studies that revealed the positive effects on cardiac function in animals hemodiluted with HVPE.

  19. Sex and nitric oxide bioavailability interact to modulate interstitial PO2 in healthy rat skeletal muscle.

    Science.gov (United States)

    Craig, Jesse C; Colburn, Trenton D; Hirai, Daniel M; Schettler, Michael J; Musch, Timothy I; Poole, David C

    2018-01-25

    Pre-menopausal women express reduced blood pressure and risk of cardiovascular disease relative to age-matched men. This purportedly relates to elevated estrogen levels increasing nitric oxide synthase (NOS) activity and NO-mediated vasorelaxation. We tested the hypotheses that female rat skeletal muscle would: 1) evince higher O 2 delivery-to-utilization ratio (Q̇O 2 /V̇O 2 ) during contractions; and 2) express greater modulation of Q̇O 2 /V̇O 2 with changes to NO bioavailability, compared to males. The spinotrapezius muscle of Sprague-Dawley rats (females (♀)=8, males (♂)=8) was surgically exposed and electrically-stimulated (180s, 1Hz, 6V). OxyphorG4 was injected into the muscle and phosphorescence quenching employed to determine the temporal profile of interstitial PO 2 (PO 2is , determined by Q̇O 2 /V̇O 2 ). This was performed under three conditions: control (CON), 300 µM sodium nitroprusside (SNP; NO donor), and 1.5 mM L-arginine methyl ester (L-NAME; NOS blockade) superfusion. No sex differences were found for the PO 2is kinetics parameters in CON or L-NAME (p>0.05), but females elicited a lower baseline following SNP (♂:42{plus minus}3 vs ♀:36{plus minus}2 mmHg, p0.05). The total NO effect (SNP minus L-NAME) on PO 2is was not different between sexes. However, the spread across both conditions was shifted to a lower absolute range for females (reduced SNP baseline and greater reduction following L-NAME). These data support that females have a greater reliance on basal NO bioavailability and males have greater responsiveness to exogenous NO and less responsiveness to reduced endogenous NO.

  20. Modulation of Apoptosis Pathways by Oxidative Stress and Autophagy in β Cells

    Directory of Open Access Journals (Sweden)

    Maorong Wang

    2012-01-01

    Full Text Available Human islets isolated for transplantation are exposed to multiple stresses including oxidative stress and hypoxia resulting in significant loss of functional β cell mass. In this study we examined the modulation of apoptosis pathway genes in islets exposed to hydrogen peroxide, peroxynitrite, hypoxia, and cytokines. We observed parallel induction of pro- and antiapoptotic pathways and identified several novel genes including BFAR, CARD8, BNIP3, and CIDE-A. As BNIP3 is an inducer of autophagy, we examined this pathway in MIN6 cells, a mouse beta cell line and in human islets. Culture of MIN6 cells under low serum conditions increased the levels of several proteins in autophagy pathway, including ATG4, Beclin 1, LAMP-2, and UVRAG. Amino acid deprivation led to induction of autophagy in human islets. Preconditioning of islets with inducers of autophagy protected them from hypoxia-induced apoptosis. However, induction of autophagy during hypoxia exacerbated apoptotic cell death. ER stress led to induction of autophagy and apoptosis in β cells. Overexpression of MnSOD, an enzyme that scavenges free radicals, resulted in protection of MIN6 cells from cytokine-induced apoptosis. Ceramide, a mediator of cytokine-induced injury, reduced the active phosphorylated form of Akt and downregulated the promoter activity of the antiapoptotic gene bcl-2. Furthermore, cytokine-stimulated JNK pathway downregulated the bcl-2 promoter activity which was reversed by preincubation with SP600125, a JNK inhibitor. Our findings suggest that β cell apoptosis by multiple stresses in islets isolated for transplantation is the result of orchestrated gene expression in apoptosis pathway.

  1. Is Modulation of Oxidative Stress an Answer? The State of the Art of Redox Therapeutic Actions in Neurodegenerative Diseases

    Directory of Open Access Journals (Sweden)

    Valerio Chiurchiù

    2016-01-01

    Full Text Available The central nervous system is particularly sensitive to oxidative stress due to many reasons, including its high oxygen consumption even under basal conditions, high production of reactive oxygen and nitrogen species from specific neurochemical reactions, and the increased deposition of metal ions in the brain with aging. For this reason, along with inflammation, oxidative stress seems to be one of the main inducers of neurodegeneration, causing excitotoxicity, neuronal loss, and axonal damage, ultimately being now considered a key element in the onset and progression of several neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, multiple sclerosis, and hereditary spastic paraplegia. Thus, the present paper reviews the role of oxidative stress and of its mechanistic insights underlying the pathogenesis of these neurodegenerative diseases, with particular focus on current studies on its modulation as a potential and promising therapeutic strategy.

  2. Bi-modified Pd/C catalyst via irreversible adsorption and its catalytic activity for ethanol oxidation in alkaline medium

    International Nuclear Information System (INIS)

    Cai, Jindi; Huang, Yiyin; Guo, Yonglang

    2013-01-01

    Highlights: • Pd-Bi/C catalysts were easily prepared by irreversible adsorption of Bi on Pd/C surface. • The adsorption of Bi increases the oxygen-containing species obviously on Pd-Bi/C surface. • Only a little amount of Bi on Pd-Bi/C can play a significant role in ethanol oxidation reaction (EOR). • Current density of EOR on Pd-Bi/C (20:1) is 2.4 times higher than that on Pd/C. • Anti-poisoning ability and durability of Pd-Bi/C (20:1) is greatly enhanced. -- Abstract: A facile approach to promote ethanol electro-oxidation on Pd-based catalysts is presented by the modification of Bi on Pd/C catalyst via irreversible adsorption. X-ray diffraction (XRD), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) measurements show that the modification of Bi has no significant effect on the Pd morphology and particle size distribution. Bi(III) and Pd(0) are the dominant forms in Pd-Bi/C catalyst. Electrochemical tests show that the modification of the appropriate amount of Bi on Pd/C catalyst can remarkably enhance activity toward ethanol oxidation reaction (EOR) up to about 2.4 times higher compared to Pd/C catalyst. The Pd-Bi/C (20:1) catalyst exhibits excellent stability and enhances CO tolerance. The enhanced electrochemical performance of Pd-Bi/C catalyst is attributed to the electronic effect and the bifunctional mechanism. The high exchange current density and the low apparent activation energy on Pd-Bi/C (20:1) catalyst reveal its faster kinetics and higher intrinsic activity compared to Pd/C catalyst

  3. Studies on the kinetics of UO2 dissolution in carbonate-bicarbonate medium using sodium hypochlorite as oxidant

    International Nuclear Information System (INIS)

    Sharma, J.N.; Bhattacharya, K.; Swami, R.G.; Tangri, S.K.; Mukherjee, T.K.

    1996-01-01

    The dissolution of UO 2 in carbonate-bicarbonate solutions containing sodium hypochlorite as an oxidant has been investigated. The effect of temperature, sodium hypochlorite concentration and stirring speed was examined. In the temperature range of 303 to 318 K, the leaching reaction displayed linear kinetics. Apparent activation energy obtained from the differential approach was found to be 57 kJ mol -1 . This relatively high activation energy value indicates a chemically controlled behavior of UO 2 dissolution. The order of reaction with respect to sodium hypochlorite concentration was found to be unity. (author). 18 refs., 6 figs

  4. Anti-oxidative defences are modulated differentially in three freshwater teleosts in response to ammonia-induced oxidative stress.

    Directory of Open Access Journals (Sweden)

    Amit Kumar Sinha

    Full Text Available Oxidative stress and the antioxidant response induced by high environmental ammonia (HEA were investigated in the liver and gills of three freshwater teleosts differing in their sensitivities to ammonia. The highly ammonia-sensitive salmonid Oncorhynchus mykiss (rainbow trout, the less ammonia sensitive cyprinid Cyprinus carpio (common carp and the highly ammonia-resistant cyprinid Carassius auratus (goldfish were exposed to 1 mM ammonia (as NH4HCO3 for 0 h (control, 3 h, 12 h, 24 h, 48 h, 84 h and 180 h. Results show that HEA exposure increased ammonia accumulation significantly in the liver of all the three fish species from 24 h-48 h onwards which was associated with an increment in oxidative stress, evidenced by elevation of xanthine oxidase activity and levels of hydrogen peroxide (H2O2 and malondialdehyde (MDA. Unlike in trout, H2O2 and MDA accumulation in carp and goldfish liver was restored to control levels (84 h-180 h; which was accompanied by a concomitant increase in superoxide dismutase (SOD, catalase (CAT, ascorbate peroxidase activity and reduced ascorbate content. Many of these defence parameters remained unaffected in trout liver, while components of the glutathione redox cycle (reduced glutathione, glutathione peroxidase and glutathione reductase enhanced to a greater extent. The present findings suggest that trout rely mainly on glutathione dependent defensive mechanism while carp utilize SOD, CAT and ascorbate as anti-oxidative sentinels. Hepatic cells of goldfish appear to utilize each of these protective systems, and showed more effective anti-oxidative compensatory responses towards HEA than carp, while trout were least effective. The present work also indicates that HEA exposure resulted in a relatively mild oxidative stress in the gills of all three species. This probably explains the almost complete lack of anti-oxidative responses in branchial tissue. This research suggests that oxidative stress, as well as the

  5. Anti-oxidative defences are modulated differentially in three freshwater teleosts in response to ammonia-induced oxidative stress.

    Science.gov (United States)

    Sinha, Amit Kumar; AbdElgawad, Hamada; Giblen, Terri; Zinta, Gaurav; De Rop, Michelle; Asard, Han; Blust, Ronny; De Boeck, Gudrun

    2014-01-01

    Oxidative stress and the antioxidant response induced by high environmental ammonia (HEA) were investigated in the liver and gills of three freshwater teleosts differing in their sensitivities to ammonia. The highly ammonia-sensitive salmonid Oncorhynchus mykiss (rainbow trout), the less ammonia sensitive cyprinid Cyprinus carpio (common carp) and the highly ammonia-resistant cyprinid Carassius auratus (goldfish) were exposed to 1 mM ammonia (as NH4HCO3) for 0 h (control), 3 h, 12 h, 24 h, 48 h, 84 h and 180 h. Results show that HEA exposure increased ammonia accumulation significantly in the liver of all the three fish species from 24 h-48 h onwards which was associated with an increment in oxidative stress, evidenced by elevation of xanthine oxidase activity and levels of hydrogen peroxide (H2O2) and malondialdehyde (MDA). Unlike in trout, H2O2 and MDA accumulation in carp and goldfish liver was restored to control levels (84 h-180 h); which was accompanied by a concomitant increase in superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase activity and reduced ascorbate content. Many of these defence parameters remained unaffected in trout liver, while components of the glutathione redox cycle (reduced glutathione, glutathione peroxidase and glutathione reductase) enhanced to a greater extent. The present findings suggest that trout rely mainly on glutathione dependent defensive mechanism while carp utilize SOD, CAT and ascorbate as anti-oxidative sentinels. Hepatic cells of goldfish appear to utilize each of these protective systems, and showed more effective anti-oxidative compensatory responses towards HEA than carp, while trout were least effective. The present work also indicates that HEA exposure resulted in a relatively mild oxidative stress in the gills of all three species. This probably explains the almost complete lack of anti-oxidative responses in branchial tissue. This research suggests that oxidative stress, as well as the antioxidant

  6. Interactions between archaeal ammonia oxidizers, Nitrospira and methanotrophs modulate autotrophic nitrification in volcanic grasslands soils

    NARCIS (Netherlands)

    Daebeler, A.; Bodelier, P.L.E.; Yan, Z; Hefting, Mariet|info:eu-repo/dai/nl/256197628; Laanbroek, Riks|info:eu-repo/dai/nl/070378282

    2014-01-01

    Ammonium/ammonia is the sole energy substrate of ammonia oxidizers, and is also an essential nitrogen source for other microorganisms. Ammonia oxidizers therefore must compete with other soil microorganisms such as methane-oxidizing bacteria (MOB) in terrestrial ecosystems when ammonium

  7. EQCM behavior of copper anodes in alkaline medium and characterization of the electrocatalysis of ethanol oxidation by Cu(III

    Directory of Open Access Journals (Sweden)

    Paixão Thiago R. L. C.

    2006-01-01

    Full Text Available The anodic oxidation of copper electrodes in alkaline solutions was investigated by using voltammetry, chronoamperometry, impedance measurements and the electrochemical quartz crystal microbalance (EQCM. Experiments were carried out in NaOH solutions in the 0.1 to 3.0 mol L-1 concentration range. The formation of soluble and insoluble species such as Cu(OH4(2- and Cu2O during the electrodic dissolution of copper anodes was characterized by analyzing potentiodynamic mass responses and the relationship between mass changes and charge. On the other hand, EQCM data were not effective to confirm the nature of other copper species proposed in literature named as CuO and Cu(OH2 because of viscoelastic changes in the film layer electrodeposited onto the quartz crystal. The participation of a Cu(III soluble species in the electrocatalytic oxidation of ethanol was proved by EQCM measurements, data providing valuable information on the mechanism of the electrode process and formation of a Cu(II insoluble species from the reaction of Cu(III with ethanol.

  8. Optical Properties of Zinc Oxide Nano-particles Embedded in Dielectric Medium for UV region: Numerical Simulation

    Science.gov (United States)

    Al-Hilli, S. M.; Willander, M.

    2006-02-01

    Zinc oxide nano-particles have been used by cosmetic industry for many years because they are extensively used as agents to attenuate (absorb and/or scatter) the ultraviolet radiation. In the most UV-attenuating agent is formulated in which the metal oxide nano-particles are incorporated into liquid media or polymer media are manufactured, such as sunscreens and skin care cosmetics. In this paper we study the wavelength dependence on the particle size ( r eff = 10-100 nm) by solving the scattering problem of hexagonal ZnO particle for different shapes (plate, equal ratio, column) using the discrete dipole approximation method to find the absorption, scattering, and extinction efficiencies for the UV region (30-400 nm). A new modified hexagonal shape is introduced to determine the scattering problem and it is assumed in this study that the wavelength is comparable to the particle size. From these results, we conclude that the optimum particle radius to block the UV radiation is between r eff = 40-80 nm.

  9. Optical Properties of Zinc Oxide Nano-particles Embedded in Dielectric Medium for UV region: Numerical Simulation

    International Nuclear Information System (INIS)

    Al-Hilli, S. M.; Willander, M.

    2006-01-01

    Zinc oxide nano-particles have been used by cosmetic industry for many years because they are extensively used as agents to attenuate (absorb and/or scatter) the ultraviolet radiation. In the most UV-attenuating agent is formulated in which the metal oxide nano-particles are incorporated into liquid media or polymer media are manufactured, such as sunscreens and skin care cosmetics. In this paper we study the wavelength dependence on the particle size (r eff = 10-100 nm) by solving the scattering problem of hexagonal ZnO particle for different shapes (plate, equal ratio, column) using the discrete dipole approximation method to find the absorption, scattering, and extinction efficiencies for the UV region (30-400 nm). A new modified hexagonal shape is introduced to determine the scattering problem and it is assumed in this study that the wavelength is comparable to the particle size. From these results, we conclude that the optimum particle radius to block the UV radiation is between r eff = 40-80 nm

  10. Conditions for the formation of pure birnessite during the oxidation of Mn(II) cations in aqueous alkaline medium

    Energy Technology Data Exchange (ETDEWEB)

    Boumaiza, Hella [Laboratoire de Chimie des Matériaux et Catalyse, Faculté des Sciences de Tunis, Université El Manar (Tunisia); Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME)-UMR 7564, CNRS-Université de Lorraine, 405, rue de Vandoeuvre, 54600 Villers-lès-Nancy (France); Département de Génie Biologique et Chimique, Institut National des Sciences Appliquées et de Technologies (INSAT), Université de Carthage, Tunis (Tunisia); Coustel, Romain [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME)-UMR 7564, CNRS-Université de Lorraine, 405, rue de Vandoeuvre, 54600 Villers-lès-Nancy (France); Medjahdi, Ghouti [Institut Jean Lamour, Centre de Compétences Rayons X et Spectroscopie (X-Gamma), UMR 7198 CNRS-Université de Lorraine (France); Ruby, Christian, E-mail: Christian.ruby@univ-lorraine.fr [Laboratoire de Chimie Physique et Microbiologie pour l' Environnement (LCPME)-UMR 7564, CNRS-Université de Lorraine, 405, rue de Vandoeuvre, 54600 Villers-lès-Nancy (France); and others

    2017-04-15

    Birnessite was synthetized through redox reaction by mixing MnO{sub 4}{sup -}, Mn{sup 2+} and OH{sup -} solutions. The Mn(VII): Mn(II) ratio of 0.33 was chosen and three methods were used consisting in a quick mixing under vigorous stirring of two of the three reagents and then on the dropwise addition of the third one. The obtained solids were characterized by XRD, FTIR and XPS spectroscopies. Their average oxidation states were determined from ICP and CEC measurements while their surface properties were investigated by XPS. This study provides an increased understanding of the importance of dissolved oxygen in the formation of birnessite and hausmannite and shows the ways to obtain pure birnessite. The role of counter-ion ie. Na{sup +} or K{sup +} was also examined. - Graphical abstract: Pathways of birnessite formation. - Highlights: • Pure birnessite is prepared through a redox reaction. • Hausmannite formation is prevented by controlling dissolved O2. • The employed counterion influences the purity of birnessite. • Initial Mn(OH){sub 2} is oxidized by both MnO{sub 4}{sup -} and dissolved O{sub 2}.

  11. Electrochemical incineration of chloromethylphenoxy herbicides in acid medium by anodic oxidation with boron-doped diamond electrode

    International Nuclear Information System (INIS)

    Boye, Birame; Brillas, Enric; Marselli, Beatrice; Michaud, Pierre-Alain; Comninellis, Christos; Farnia, Giuseppe; Sandona, Giancarlo

    2006-01-01

    The electrochemical degradation of saturated solutions of herbicides 4-chloro-2-methylphenoxyacetic acid, 2-(4-chlorophenoxy)-2-methylpropionic acid and 2-(4-chloro-2-methylphenoxy)propionic acid in 1 M HClO 4 on a boron-doped diamond (BDD) thin film anode has been studied by chronoamperometry, cyclic voltammetry and bulk electrolysis. At low anodic potentials polymeric products are formed causing the fouling and deactivation of BDD. This is reactivated at high potentials when water decomposes producing hydroxyl radical as strong oxidant of organics. Electrolyses in a batch recirculation system at constant current density ≥8 mA cm -2 yielded overall decontamination of all saturated solution. The effect of current density and herbicide concentration on the degradation rate of each compound, the specific charge required for its total mineralization and instantaneous current efficiency have been investigated. Experimental results have been compared with those predicted by a theoretical model based on a fast anodic oxidation of initial herbicides, showing that at 30 mA cm -2 their degradation processes are completely controlled by mass transfer. Kinetic analysis of the change of herbicide concentration with time during electrolysis, determined by high-performance liquid chromatography, revealed that all compounds follow a pseudo first-order reaction. Aromatic intermediates and generated carboxylic acids have been identified using this technique and a general pathway for the electrochemical incineration of all herbicides on BDD is proposed

  12. Optical Properties of Zinc Oxide Nano-particles Embedded in Dielectric Medium for UV region: Numerical Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hilli, S. M., E-mail: salhilli@fy.chalmers.se; Willander, M. [Goeteborg University, Physical Electronics and Photonics, Department of Physics (Sweden)

    2006-02-15

    Zinc oxide nano-particles have been used by cosmetic industry for many years because they are extensively used as agents to attenuate (absorb and/or scatter) the ultraviolet radiation. In the most UV-attenuating agent is formulated in which the metal oxide nano-particles are incorporated into liquid media or polymer media are manufactured, such as sunscreens and skin care cosmetics. In this paper we study the wavelength dependence on the particle size (r{sub eff} = 10-100 nm) by solving the scattering problem of hexagonal ZnO particle for different shapes (plate, equal ratio, column) using the discrete dipole approximation method to find the absorption, scattering, and extinction efficiencies for the UV region (30-400 nm). A new modified hexagonal shape is introduced to determine the scattering problem and it is assumed in this study that the wavelength is comparable to the particle size. From these results, we conclude that the optimum particle radius to block the UV radiation is between r{sub eff} = 40-80 nm.

  13. Nitric oxide modulated the expression of DREAM/calsenilin/KChIP3 in inflammatory pain of rats.

    Science.gov (United States)

    Jin, Hong-Bo; Yang, Yong-Liang; Song, Ying-Li; Yang, Yong-Bin; Li, Yu-Rong

    2012-12-01

    Downstream regulatory element antagonistic modulator (DREAM) is a critical transcriptional repressor for pain modulation. The role of nitric oxide (NO) plays in modulating DREAM pain pathway in the periphery is unclear. Therefore, we investigated the role of the NO in modulation of the expression of DREAM in formalin-induced rat inflammatory pain models. Male Sprague-Dawley rats were randomly distributed into four groups: the normal group, formalin test group, Nω-nitro-L-arginine (l-NNA) group, and morphine group. One hundred microliters of 2.5 % formalin was injected into the plantar surface of the right hindpaw of rats. l-NNA (40 nmol/L) and morphine (40 nmol/L) were injected intrathecally in the hindpaw before formalin injection. The nociceptive behavioral reaction was recorded. After the formalin test, the expression of DREAM mRNA and protein in the spinal cord of the four groups were measured. The nociceptive reaction induced by injection of formalin exhibited two phases. Morphine and l-NNA significantly decreased pain scores of the second phase. The expression of DREAM was significantly increased in the rat spinal cord after formalin-induced pain. Morphine significantly upregulated the expression of DREAM, and the formalin-induced upregulation was significantly attenuated by l-NNA. NO may play an important role in the DREAM pathway modulation of inflammatory pain.

  14. Hyperglycemia adversely modulates endothelial nitric oxide synthase during anesthetic preconditioning through tetrahydrobiopterin- and heat shock protein 90-mediated mechanisms.

    Science.gov (United States)

    Amour, Julien; Brzezinska, Anna K; Jager, Zachary; Sullivan, Corbin; Weihrauch, Dorothee; Du, Jianhai; Vladic, Nikolina; Shi, Yang; Warltier, David C; Pratt, Phillip F; Kersten, Judy R

    2010-03-01

    Endothelial nitric oxide synthase activity is regulated by (6R-)5,6,7,8-tetrahydrobiopterin (BH4) and heat shock protein 90. The authors tested the hypothesis that hyperglycemia abolishes anesthetic preconditioning (APC) through BH4- and heat shock protein 90-dependent pathways. Myocardial infarct size was measured in rabbits in the absence or presence of APC (30 min of isoflurane), with or without hyperglycemia, and in the presence or absence of the BH4 precursor sepiapterin. Isoflurane-dependent nitric oxide production was measured (ozone chemiluminescence) in human coronary artery endothelial cells cultured in normal (5.5 mm) or high (20 mm) glucose conditions, with or without sepiapterin (10 or 100 microm). APC decreased myocardial infarct size compared with control experiments (26 +/- 6% vs. 46 +/- 3%, respectively; P < 0.05), and this action was blocked by hyperglycemia (43 +/- 4%). Sepiapterin alone had no effect on infarct size (46 +/- 3%) but restored APC during hyperglycemia (21 +/- 3%). The beneficial actions of sepiapterin to restore APC were blocked by the nitric oxide synthase inhibitor N (G)-nitro-L-arginine methyl ester (47 +/- 2%) and the BH4 synthesis inhibitor N-acetylserotonin (46 +/- 3%). Isoflurane increased nitric oxide production to 177 +/- 13% of baseline, and this action was attenuated by high glucose concentrations (125 +/- 6%). Isoflurane increased, whereas high glucose attenuated intracellular BH4/7,8-dihydrobiopterin (BH2) (high performance liquid chromatography), heat shock protein 90-endothelial nitric oxide synthase colocalization (confocal microscopy) and endothelial nitric oxide synthase activation (immunoblotting). Sepiapterin increased BH4/BH2 and dose-dependently restored nitric oxide production during hyperglycemic conditions (149 +/- 12% and 175 +/- 9%; 10 and 100 microm, respectively). The results indicate that tetrahydrobiopterin and heat shock protein 90-regulated endothelial nitric oxide synthase activity play a central

  15. Chemiluminescence behavior based on oxidation reaction of rhodamine B with cerium(IV) in sulfuric acid medium

    International Nuclear Information System (INIS)

    Ma Yongjun; Jin Xiaoyong; Zhou Min; Zhang Ziyu; Teng Xiulan; Chen Hui

    2003-01-01

    The chemiluminescence (CL) of the rhodamine B (RhB)-cerium(IV) system was investigated by flow-injection. Rhodamine B was suggested to be a suitable chemiluminescent reagent in acidic conditions. When the concentration of rhodamine B was 100 mg l -1 and cerium sulfate was 1.6 mmol l -1 in sulfuric acid, the chemiluminescent intensity was found to be highest by using 0.3 mol l -1 sulfuric acid as a carrier solution. The particular chemiluminescent system could tolerate such distinct acidic environments that it was utilized for detecting many compounds that are stable in acidic solutions. Furthermore, by virtue of IR, UV-Vis and luminescence spectroscopic measurements, the chemiluminescent behavior of rhodamine B was studied and a possible mechanism for this chemiluminescent reaction was proposed. The emitter was affirmed to be a radical species due to one of the oxidation products of RhB; the chemiluminescent emissive wavelength was about 425 nm

  16. Kinetics and Mechanism of Oxidation of Triethylene Glycol and Tetraethylene Glycol by Ditelluratoargentate (III in Alkaline Medium

    Directory of Open Access Journals (Sweden)

    Jinhuan Shan

    2013-01-01

    Full Text Available The kinetics of oxidation of triethylene glycol and tetraethylene glycol by ditelluratoargentate (III (DTA in alkaline liquids has been studied spectrophotometrically in the temperature range of 293.2 K–313.2 K. The reaction rate showed first-order dependence in DTA and fractional order with respect to triethylene glycol or tetraethylene glycol. It was found that the pseudo-first-order rate constant (kobs increased with an increase in concentration of OH− and a decrease in concentration of H4TeO6 2−. There was a negative salt effect and no free radicals were detected. A plausible mechanism involving a two-electron transfer was proposed, and the rate equations derived from the mechanism explained all the experimental results and observations. The activation parameters along with the rate constants of the rate-determining step were calculated.

  17. On calculation of dependence of ion sorption by oxides and hydroxides on ph of medium from logistic curve

    International Nuclear Information System (INIS)

    Artyukhin, P.I.

    1988-01-01

    Critical consideration of the earlier suggested method for calculation of dependences of relative sorption (S) of microcomponents (MC) with oxides and hydroxides on the pH solution by the so-called logistic curve is given, and it is concluded that the presented equation for the curve does not have properties of the logistic function and contradicts the experiment. The equation really describing the dependence of S on pH and complying with criteria imposed for logistic functions is shown to proceed from existing model representations on MC sorption with hydroxides, and this problem may be easily solved graphically by drawing the dependence lg (S/1-S)=A+mpH, where A-constant, m + -MC aqua-ion charge. The made conclusions are illustrated on the example of 14m In, 91 Y, 64 Cu coprecipitation with iron hydroxide

  18. Probing Transition-Metal Silicides as PGM-Free Catalysts for Hydrogen Oxidation and Evolution in Acidic Medium

    Science.gov (United States)

    Mittermeier, Thomas; Madkikar, Pankaj; Wang, Xiaodong; Gasteiger, Hubert A.; Piana, Michele

    2017-01-01

    In this experimental study, we investigate various transition-metal silicides as platinum-group-metal-(PGM)-free electrocatalysts for the hydrogen oxidation reaction (HOR), and for the hydrogen evolution reaction (HER) in acidic environment for the first time. Using cyclic voltammetry in 0.1 M HClO4, we first demonstrate that the tested materials exhibit sufficient stability against dissolution in the relevant potential window. Further, we determine the HOR and HER activities for Mo, W, Ta, Ni and Mo-Ni silicides in rotating disk electrode experiments. In conclusion, for the HOR only Ni2Si shows limited activity, and the HER activity of the investigated silicides is considerably lower compared to other PGM-free HER catalysts reported in the literature. PMID:28773022

  19. Degradation of trans-ferulic acid in acidic aqueous medium by anodic oxidation, electro-Fenton and photoelectro-Fenton

    Energy Technology Data Exchange (ETDEWEB)

    Flores, Nelly; Sirés, Ignasi; Garrido, José Antonio; Centellas, Francesc; Rodríguez, Rosa María; Cabot, Pere Lluís; Brillas, Enric, E-mail: brillas@ub.edu

    2016-12-05

    Highlights: • trans-Ferulic acid degradation by EAOPs using a stirred BDD/air-diffusion cell. • Slow substrate abatement and poor mineralization by AO-H{sub 2}O{sub 2}. • 98% Mineralization by PEF, but with rapid and similar substrate decay than by EF. • Quicker degradation by SPEF due to the more potent photolytic action of sunlight. • Reaction pathway with four primary aromatic products and three final carboxylic acids. - Abstract: Solutions of pH 3.0 containing trans-ferulic acid, a phenolic compound in olive oil mill wastewater, have been comparatively degraded by anodic oxidation with electrogenerated H{sub 2}O{sub 2} (AO-H{sub 2}O{sub 2}), electro-Fenton (EF) and photoelectro-Fenton (PEF). Trials were performed with a BDD/air-diffusion cell, where oxidizing ·OH was produced from water discharge at the BDD anode and/or in the solution bulk from Fenton’s reaction between cathodically generated H{sub 2}O{sub 2} and added catalytic Fe{sup 2+}. The substrate was very slowly removed by AO-H{sub 2}O{sub 2}, whereas it was very rapidly abated by EF and PEF, at similar rate in both cases, due to its fast reaction with ·OH in the bulk. The AO-H{sub 2}O{sub 2} process yielded a slightly lower mineralization than EF, which promoted the accumulation of barely oxidizable products like Fe(III) complexes. In contrast, the fast photolysis of these latter species under irradiation with UVA light in PEF led to an almost total mineralization with 98% total organic carbon decay. The effect of current density and substrate concentration on the performance of all treatments was examined. Several solar PEF (SPEF) trials showed its viability for the treatment of wastewater containing trans-ferulic acid at larger scale. Four primary aromatic products were identified by GC–MS analysis of electrolyzed solutions, and final carboxylic acids like fumaric, acetic and oxalic were detected by ion-exclusion HPLC. A reaction sequence for trans-ferulic acid mineralization

  20. Electrocatalytic oxidation of ethanol in acid medium: Enhancement of activity of vulcan-supported Platinum-based nanoparticles upon immobilization within nanostructured zirconia matrices

    Science.gov (United States)

    Rutkowska, Iwona A.; Kulesza, Pawel J.

    2014-09-01

    Composite electrocatalytic materials that utilize carbon (Vulcan) supported Pt or PtRu nanoparticles dispersed within thin films of zirconia (ZrO2) are considered here for oxidation of such a biofuel as ethanol in acid medium. The systems were characterized using electrochemical techniques as well as transmission electron microscopy. The enhancement of activity was clearly evident upon comparison of the respective voltammetric and chronoamperometric current densities recorded (at room temperature in 0.5 mol dm-3H2SO4 containing 0.5 mol dm-3 ethanol) using the Vulcan supported Pt and PtRu catalysts in the presence and absence of zirconia. In all cases, the noble metal loading was the same, 100 μg cm-2. Apparently, the existence of large population of hydroxyl groups (originating from zirconia) in the vicinity of Pt-based catalyst, in addition to possible specific interactions between zirconia and the ruthenium component of PtRu, facilitated the oxidative removal (from Pt) of the passivating (e.g., CO) reaction intermediates (adsorbates). By utilizing carbon supported, rather than bare or unsupported, Pt or PtRu nanoparticles (dispersed within the semiconducting zirconia), the overall charge distribution at the electrocatalytic interface was improved.

  1. Chemiluminescence behavior based on oxidation reaction of rhodamine B with cerium(IV) in sulfuric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yongjun; Jin Xiaoyong; Zhou Min; Zhang Ziyu; Teng Xiulan; Chen Hui

    2003-08-18

    The chemiluminescence (CL) of the rhodamine B (RhB)-cerium(IV) system was investigated by flow-injection. Rhodamine B was suggested to be a suitable chemiluminescent reagent in acidic conditions. When the concentration of rhodamine B was 100 mg l{sup -1} and cerium sulfate was 1.6 mmol l{sup -1} in sulfuric acid, the chemiluminescent intensity was found to be highest by using 0.3 mol l{sup -1} sulfuric acid as a carrier solution. The particular chemiluminescent system could tolerate such distinct acidic environments that it was utilized for detecting many compounds that are stable in acidic solutions. Furthermore, by virtue of IR, UV-Vis and luminescence spectroscopic measurements, the chemiluminescent behavior of rhodamine B was studied and a possible mechanism for this chemiluminescent reaction was proposed. The emitter was affirmed to be a radical species due to one of the oxidation products of RhB; the chemiluminescent emissive wavelength was about 425 nm.

  2. Downregulation of miR-205 modulates cell susceptibility to oxidative and endoplasmic reticulum stresses in renal tubular cells.

    Directory of Open Access Journals (Sweden)

    Shiyo Muratsu-Ikeda

    Full Text Available BACKGROUND: Oxidative stress and endoplasmic reticulum (ER stress play a crucial role in tubular damage in both acute kidney injury (AKI and chronic kidney disease (CKD. While the pathophysiological contribution of microRNAs (miRNA to renal damage has also been highlighted, the effect of miRNA on renal damage under oxidative and ER stresses conditions remains elusive. METHODS: We assessed changes in miRNA expression in the cultured renal tubular cell line HK-2 under hypoxia-reoxygenation-induced oxidative stress or ER stress using miRNA microarray assay and real-time RT-PCR. The pathophysiological effect of miRNA was evaluated by cell survival rate, intracellular reactive oxygen species (ROS level, and anti-oxidant enzyme expression in miRNA-inhibited HK-2 or miRNA-overexpressed HK-2 under these stress conditions. The target gene of miRNA was identified by 3'-UTR-luciferase assay. RESULTS: We identified 8 and 10 miRNAs whose expression was significantly altered by oxidative and ER stresses, respectively. Among these, expression of miR-205 was markedly decreased in both stress conditions. Functional analysis revealed that decreased miR-205 led to an increase in cell susceptibility to oxidative and ER stresses, and that this increase was associated with the induction of intracellular ROS and suppression of anti-oxidant enzymes. While increased miR-205 by itself made no change in cell growth or morphology, cell viability under oxidative or ER stress conditions was partially restored. Further, miR-205 bound to the 3'-UTR of the prolyl hydroxylase 1 (PHD1/EGLN2 gene and suppressed the transcription level of EGLN2, which modulates both intracellular ROS level and ER stress state. CONCLUSIONS: miR-205 serves a protective role against both oxidative and ER stresses via the suppression of EGLN2 and subsequent decrease in intracellular ROS. miR-205 may represent a novel therapeutic target in AKI and CKD associated with oxidative or ER stress in tubules.

  3. A High Temperature Experimental Characterization Procedure for Oxide-Based Thermoelectric Generator Modules under Transient Conditions

    DEFF Research Database (Denmark)

    Man, Elena Anamaria; Schaltz, Erik; Rosendahl, Lasse

    2015-01-01

    Characterization methods for thermoelectric generator (TEG) modules play an important role in studying their behavior and in enhancing the performance and simulation of TEG systems also. The purpose of this study is to analyze the behavior in transient and steady-state of the temperature applied...... is of experimental nature, it includes modules of different leg lengths and it is performed on a test rig known as TEGeta, which can be used to assess the output characteristics of TEG modules at different load values and temperature conditions. The setup offers the possibility to control the hot side temperature up...

  4. Role of Myeloperoxidase Oxidants in the Modulation of Cellular Lysosomal Enzyme Function

    DEFF Research Database (Denmark)

    Ismael, Fahd O; Barrett, Tessa J; Sheipouri, Diba

    2016-01-01

    Low-density lipoprotein (LDL) is the major source of lipid within atherosclerotic lesions. Myeloperoxidase (MPO) is present in lesions and forms the reactive oxidants hypochlorous acid (HOCl) and hypothiocyanous acid (HOSCN). These oxidants modify LDL and have been strongly linked with the develo...

  5. Modulation of cholinergic airway reactivity and nitric oxide production by endogenous arginase activity

    NARCIS (Netherlands)

    Meurs, Herman; Hamer, M.A M; Pethe, S; Vadon-Le Goff, S; Boucher, J.-L; Zaagsma, Hans

    1 Cholinergic airway constriction is functionally antagonized by agonist-induced constitutive nitric oxide synthase (cNOS)-derived nitric oxide (NO). Since cNOS and arginase, which hydrolyzes L-arginine to L-ornithine and urea, use L-arginine as a common substrate, competition between both enzymes

  6. Increased Nitric Oxide Bioavailability and Decreased Sympathetic Modulation Are Involved in Vascular Adjustments Induced by Low-Intensity Resistance Training

    Science.gov (United States)

    Macedo, Fabrício N.; Mesquita, Thassio R. R.; Melo, Vitor U.; Mota, Marcelo M.; Silva, Tharciano L. T. B.; Santana, Michael N.; Oliveira, Larissa R.; Santos, Robervan V.; Miguel dos Santos, Rodrigo; Lauton-Santos, Sandra; Santos, Marcio R. V.; Barreto, Andre S.; Santana-Filho, Valter J.

    2016-01-01

    Resistance training is one of the most common kind of exercise used nowadays. Long-term high-intensity resistance training are associated with deleterious effects on vascular adjustments. On the other hand, is unclear whether low-intensity resistance training (LI-RT) is able to induce systemic changes in vascular tone. Thus, we aimed to evaluate the effects of chronic LI-RT on endothelial nitric oxide (NO) bioavailability of mesenteric artery and cardiovascular autonomic modulation in healthy rats. Wistar animals were divided into two groups: exercised (Ex) and sedentary (SED) rats submitted to the resistance (40% of 1RM) or fictitious training for 8 weeks, respectively. After LI-RT, hemodynamic measurements and cardiovascular autonomic modulation by spectral analysis were evaluated. Vascular reactivity, NO production and protein expression of endothelial and neuronal nitric oxide synthase isoforms (eNOS and nNOS, respectively) were evaluated in mesenteric artery. In addition, cardiac superoxide anion production and ventricle morphological changes were also assessed. In vivo measurements revealed a reduction in mean arterial pressure and heart rate after 8 weeks of LI-RT. In vitro studies showed an increased acetylcholine (ACh)-induced vasorelaxation and greater NOS dependence in Ex than SED rats. Hence, decreased phenylephrine-induced vasoconstriction was found in Ex rats. Accordingly, LI-RT increased the NO bioavailability under basal and ACh stimulation conditions, associated with upregulation of eNOS and nNOS protein expression in mesenteric artery. Regarding autonomic control, LI-RT increased spontaneous baroreflex sensitivity, which was associated to reduction in both, cardiac and vascular sympathetic modulation. No changes in cardiac superoxide anion or left ventricle morphometric parameters after LI-RT were observed. In summary, these results suggest that RT promotes beneficial vascular adjustments favoring augmented endothelial NO bioavailability and

  7. Thermopower modulation clarification of the intrinsic effective mass in transparent oxide semiconductor BaSnO3

    OpenAIRE

    Sanchela, Anup V.; Onozato, Takaki; Feng, Bin; Ikuhara, Yuichi; Ohta, Hiromichi

    2017-01-01

    The exact intrinsic carrier effective mass m* of a well-studied transparent oxide semiconductor BaSnO3 is unknown because the reported m* values are scattered from 0.06m(0) to 3.7m(0). This paper identifies the intrinsic m* of BaSnO3, m* = 0.40 +/- 0.01m(0), by the thermopower modulation clarification method and determines the threshold of the degenerate/nondegenerate semiconductor. At the threshold, the thermopower values of both the La-doped BaSnO3 and BaSnO3 thin-film transistor structures...

  8. Thermopower modulation clarification of the intrinsic effective mass in a transparent oxide semiconductor, BaSnO3

    OpenAIRE

    Sanchela, Anup V.; Onozato, Takaki; Feng, Bin; Ikuhara, Yuichi; Ohta, Hiromichi

    2017-01-01

    Although there are so many reports on the carrier effective mass (m*) of a transparent oxide semiconductor BaSnO3, it is almost impossible to know the intrinsic m* value because the reported m* values are scattered from 0.06 to 3.7 m0. Here we successfully clarified the intrinsic m* of BaSnO3, m*=0.40 0.01 m0, by the thermopower modulation clarification method. We also found the threshold of degenerate/non-degenerate semiconductor of BaSnO3; At the threshold, the thermopower value of both La-...

  9. Samarium Doped Cerium Oxide Clusters: a Study on the Modulation of Electronic Structure

    Science.gov (United States)

    Topolski, Josey E.; Kafader, Jared O.; Marrero-Colon, Vicmarie; Chick Jarrold, Caroline

    2017-06-01

    Cerium oxide is known for its use in solid oxide fuel cells due to its high ionic conductivity. The doping of trivalent samarium atoms into cerium oxide is known to enhance the ionic conductivity through the generation of additional oxygen vacancies. This study probes the electronic structure of Sm_{x}Ce_{y}O_{z} (x+y=3, z=2-4) anion and neutral clusters. Anion photoelectron spectra of these mixed metal clusters exhibit additional spectral features not present in the previously studied cerium oxide clusters. Density functional theory calculations have been used to aid interpretation of collected spectra. The results of this work can be used to inform the design of materials used for solid oxide fuel cells.

  10. Modulation of vasodilator response via the nitric oxide pathway after acute methyl mercury chloride exposure in rats.

    Science.gov (United States)

    Omanwar, S; Saidullah, B; Ravi, K; Fahim, M

    2013-01-01

    Mercury exposure induces endothelial dysfunction leading to loss of endothelium-dependent vasorelaxation due to decreased nitric oxide (NO) bioavailability via increased oxidative stress. Our aim was to investigate whether acute treatment with methyl mercury chloride changes the endothelium-dependent vasodilator response and to explore the possible mechanisms behind the observed effects. Wistar rats were treated with methyl mercury chloride (5 mg/kg, po.). The methyl mercury chloride treatment resulted in an increased aortic vasorelaxant response to acetylcholine (ACh). In methyl-mercury-chloride-exposed rats, the % change in vasorelaxant response of ACh in presence of Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME; 10(-4) M) was significantly increased, and in presence of glybenclamide (10(-5) M), the response was similar to that of untreated rats, indicating the involvement of NO and not of endothelium-derived hyperpolarizing factor (EDHF). In addition, superoxide dismutase (SOD) + catalase treatment increased the NO modulation of vasodilator response in methyl-mercury-chloride-exposed rats. Our results demonstrate an increase in the vascular reactivity to ACh in aorta of rats acutely exposed to methyl mercury chloride. Methyl mercury chloride induces nitric oxide synthase (NOS) and increases the NO production along with inducing oxidative stress without affecting the EDHF pathway.

  11. Modulation of Vasodilator Response via the Nitric Oxide Pathway after Acute Methyl Mercury Chloride Exposure in Rats

    Directory of Open Access Journals (Sweden)

    S. Omanwar

    2013-01-01

    Full Text Available Mercury exposure induces endothelial dysfunction leading to loss of endothelium-dependent vasorelaxation due to decreased nitric oxide (NO bioavailability via increased oxidative stress. Our aim was to investigate whether acute treatment with methyl mercury chloride changes the endothelium-dependent vasodilator response and to explore the possible mechanisms behind the observed effects. Wistar rats were treated with methyl mercury chloride (5 mg/kg, po.. The methyl mercury chloride treatment resulted in an increased aortic vasorelaxant response to acetylcholine (ACh. In methyl-mercury-chloride-exposed rats, the % change in vasorelaxant response of ACh in presence of Nω-Nitro-L-arginine methyl ester hydrochloride (L-NAME; 10-4 M was significantly increased, and in presence of glybenclamide (10-5 M, the response was similar to that of untreated rats, indicating the involvement of NO and not of endothelium-derived hyperpolarizing factor (EDHF. In addition, superoxide dismutase (SOD + catalase treatment increased the NO modulation of vasodilator response in methyl-mercury-chloride-exposed rats. Our results demonstrate an increase in the vascular reactivity to ACh in aorta of rats acutely exposed to methyl mercury chloride. Methyl mercury chloride induces nitric oxide synthase (NOS and increases the NO production along with inducing oxidative stress without affecting the EDHF pathway.

  12. ZNF32 protects against oxidative stress-induced apoptosis by modulating C1QBP transcription

    Science.gov (United States)

    Li, Yanyan; Wei, Yuyan; Gong, Di; Gao, Junping; Zhang, Jie; Tan, Weiwei; Wen, Tianfu; Zhang, Le; Huang, Lugang; Xiang, Rong; Lin, Ping; Wei, Yuquan

    2015-01-01

    Reactive oxygen species (ROS)-driven oxidative stress has been recognized as a critical inducer of cancer cell death in response to therapeutic agents. Our previous studies have demonstrated that zinc finger protein (ZNF)32 is key to cell survival upon oxidant stimulation. However, the mechanisms by which ZNF32 mediates cell death remain unclear. Here, we show that at moderate levels of ROS, Sp1 directly binds to two GC boxes within the ZNF32 promoter to activate ZNF32 transcription. Alternatively, at cytotoxic ROS concentrations, ZNF32 expression is repressed due to decreased binding activity of Sp1. ZNF32 overexpression maintains mitochondrial membrane potential and enhances the antioxidant capacity of cells to detoxify ROS, and these effects promote cell survival upon pro-oxidant agent treatment. Alternatively, ZNF32-deficient cells are more sensitive and vulnerable to oxidative stress-induced cell injury. Mechanistically, we demonstrate that complement 1q-binding protein (C1QBP) is a direct target gene of ZNF32 that inactivates the p38 MAPK pathway, thereby exerting the protective effects of ZNF32 on oxidative stress-induced apoptosis. Taken together, our findings indicate a novel mechanism by which the Sp1-ZNF32-C1QBP axis protects against oxidative stress and implicate a promising strategy that ZNF32 inhibition combined with pro-oxidant anticancer agents for hepatocellular carcinoma treatment. PMID:26497555

  13. Calcium-activated potassium channels - a therapeutic target for modulating nitric oxide in cardiovascular disease?

    DEFF Research Database (Denmark)

    Dalsgaard, Thomas; Kroigaard, Christel; Simonsen, Ulf

    2010-01-01

    IMPORTANCE OF THE FIELD: Cardiovascular risk factors are often associated with endothelial dysfunction, which is also prognostic for occurrence of cardiovascular events. Endothelial dysfunction is reflected by blunted vasodilatation and reduced nitric oxide (NO) bioavailability. Endothelium...

  14. Regulation of fatty acid oxidation in mouse cumulus-oocyte complexes during maturation and modulation by PPAR agonists.

    Directory of Open Access Journals (Sweden)

    Kylie R Dunning

    Full Text Available Fatty acid oxidation is an important energy source for the oocyte; however, little is known about how this metabolic pathway is regulated in cumulus-oocyte complexes. Analysis of genes involved in fatty acid oxidation showed that many are regulated by the luteinizing hormone surge during in vivo maturation, including acyl-CoA synthetases, carnitine transporters, acyl-CoA dehydrogenases and acetyl-CoA transferase, but that many are dysregulated when cumulus-oocyte complexes are matured under in vitro maturation conditions using follicle stimulating hormone and epidermal growth factor. Fatty acid oxidation, measured as production of ³H₂O from [³H]palmitic acid, occurs in mouse cumulus-oocyte complexes in response to the luteinizing hormone surge but is significantly reduced in cumulus-oocyte complexes matured in vitro. Thus we sought to determine whether fatty acid oxidation in cumulus-oocyte complexes could be modulated during in vitro maturation by lipid metabolism regulators, namely peroxisome proliferator activated receptor (PPAR agonists bezafibrate and rosiglitazone. Bezafibrate showed no effect with increasing dose, while rosiglitazone dose dependently inhibited fatty acid oxidation in cumulus-oocyte complexes during in vitro maturation. To determine the impact of rosiglitazone on oocyte developmental competence, cumulus-oocyte complexes were treated with rosiglitazone during in vitro maturation and gene expression, oocyte mitochondrial activity and embryo development following in vitro fertilization were assessed. Rosiglitazone restored Acsl1, Cpt1b and Acaa2 levels in cumulus-oocyte complexes and increased oocyte mitochondrial membrane potential yet resulted in significantly fewer embryos reaching the morula and hatching blastocyst stages. Thus fatty acid oxidation is increased in cumulus-oocyte complexes matured in vivo and deficient during in vitro maturation, a known model of poor oocyte quality. That rosiglitazone further

  15. Modulation of apoptosis by sulforaphane is associated with PGC-1α stimulation and decreased oxidative stress in cardiac myoblasts.

    Science.gov (United States)

    Fernandes, Rafael O; Bonetto, Jéssica H P; Baregzay, Boran; de Castro, Alexandre L; Puukila, Stephanie; Forsyth, Heidi; Schenkel, Paulo C; Llesuy, Susana F; Brum, Ilma Simoni; Araujo, Alex Sander R; Khaper, Neelam; Belló-Klein, Adriane

    2015-03-01

    Sulforaphane is a naturally occurring isothiocyanate capable of stimulating cellular antioxidant defenses and inducing phase 2 detoxifying enzymes, which can protect cells against oxidative damage. Oxidative stress and apoptosis are intimately involved in the pathophysiology of cardiac diseases. Although sulforaphane is known for its anticancer benefits, its role in cardiac cells is just emerging. The aim of the present study was to investigate whether sulforaphane can modulate oxidative stress, apoptosis, and correlate with PGC-1α, a transcriptional cofactor involved in energy metabolism. H9c2 cardiac myoblasts were incubated with R-sulforaphane 5 µmol/L for 24 h. Cell viability, ANP gene expression, oxidative stress and apoptosis markers, and protein expression of PGC-1α were studied. In cells treated with sulforaphane, cellular viability increased (12 %) and ANP gene expression decreased (46 %) compared to control cells. Moreover, sulforaphane induced a significant increase in superoxide dismutase (103 %), catalase (101 %), and glutathione S-transferase (72 %) activity, reduced reactive oxygen species levels (15 %) and lipid peroxidation (65 %), as well as stimulated the expression of the cytoprotective enzyme heme oxygenase-1 (4-fold). Sulforaphane also promoted an increase in the expression of the anti-apoptotic protein Bcl-2 (60 %), decreasing the Bax/Bcl-2 ratio. Active Caspase 3\\7 and p-JNK/JNK were also reduced by sulforaphane, suggesting a reduction in apoptotic signaling. This was associated with an increased protein expression of PGC-1α (42 %). These results suggest that sulforaphane offers cytoprotection to cardiac cells by activating PGC1-α, reducing oxidative stress, and decreasing apoptosis signaling.

  16. Low oxygen reduces the modulation to an oxidative phenotype in monolayer-expanded chondrocytes.

    Science.gov (United States)

    Heywood, Hannah K; Lee, David A

    2010-01-01

    Autologous chondrocyte implantation requires a phase of in vitro cell expansion, achieved by monolayer culture under atmospheric oxygen levels. Chondrocytes reside under low oxygen conditions in situ and exhibit a glycolytic metabolism. However, oxidative phosphorylation rises progressively during culture, with concomitant reactive oxygen species production. We determine if the high oxygen environment in vitro provides the transformation stimulus. Articular chondrocytes were cultured in monolayer for up to 14 days under 2%, 5%, or 20% oxygen. Expansion under 2% and 5% oxygen reduced the rate at which the cells developed an oxidative phenotype compared to 20% oxygen. However, at 40 +/- 4 fmol cell(-1) h(-1) the oxygen consumption by chondrocytes expanded under 2% oxygen for 14 days was still 14 times the value observed for freshly isolated cells. Seventy-five to 78% of the increased oxygen consumption was accounted for by oxidative phosphorylation (oligomycin sensitive). Expansion under low oxygen also reduced cellular proliferation and 8-hydroxyguanosine release, a marker of oxidative DNA damage. However, these parameters remained elevated compared to freshly isolated cells. Thus, expansion under physiological oxygen levels reduces, but does not abolish, the induction of an oxidative energy metabolism. We conclude that simply transferring chondrocytes to low oxygen is not sufficient to either maintain or re-establish a normal energy metabolism. Furthermore, a hydrophobic polystyrene culture surface which promotes rounded cell morphology had no effect on the development of an oxidative metabolism. Although the shift towards an oxidative energy metabolism is often accompanied by morphological changes, this study does not support the hypothesis that it is driven by them.

  17. Mechanisms of Oxidative Damage in Multiple Sclerosis and Neurodegenerative Diseases: Therapeutic Modulation via Fumaric Acid Esters

    Directory of Open Access Journals (Sweden)

    Ralf Gold

    2012-09-01

    Full Text Available Oxidative stress plays a crucial role in many neurodegenerative conditions such as Alzheimer’s disease, amyotrophic lateral sclerosis and Parkinson’s as well as Huntington’s disease. Inflammation and oxidative stress are also thought to promote tissue damage in multiple sclerosis (MS. Recent data point at an important role of anti-oxidative pathways for tissue protection in chronic-progressive MS, particularly involving the transcription factor nuclear factor (erythroid-derived 2-related factor 2 (Nrf2. Thus, novel therapeutics enhancing cellular resistance to free radicals could prove useful for MS treatment. Here, fumaric acid esters (FAE are a new, orally available treatment option which had already been tested in phase II/III MS trials demonstrating beneficial effects on relapse rates and magnetic resonance imaging markers. In vitro, application of dimethylfumarate (DMF leads to stabilization of Nrf2, activation of Nrf2-dependent transcriptional activity and abundant synthesis of detoxifying proteins. Furthermore, application of FAE involves direct modification of the inhibitor of Nrf2, Kelch-like ECH-associated protein 1. On cellular levels, the application of FAE enhances neuronal survival and protects astrocytes against oxidative stress. Increased levels of Nrf2 are detected in the central nervous system of DMF treated mice suffering from experimental autoimmune encephalomyelitis (EAE, an animal model of MS. In EAE, DMF ameliorates the disease course and improves preservation of myelin, axons and neurons. Finally, Nrf2 is also up-regulated in the spinal cord of autopsy specimens from untreated patients with MS, probably as part of a naturally occurring anti-oxidative response. In summary, oxidative stress and anti-oxidative pathways are important players in MS pathophysiology and constitute a promising target for future MS therapies like FAE.

  18. Bromate formation from the oxidation of bromide in the UV/chlorine process with low pressure and medium pressure UV lamps.

    Science.gov (United States)

    Fang, Jingyun; Zhao, Quan; Fan, Chihhao; Shang, Chii; Fu, Yun; Zhang, Xiangru

    2017-09-01

    When a bromide-containing water is treated by the ultraviolet (UV)/chlorine process, hydroxyl radicals (HO) and halogen radicals such as Cl or Br are formed due to the UV photolysis of free halogens. These reactive species may induce the formation of bromate, which is a probable human carcinogen. Bromate formation in the UV/chlorine process using low pressure (LP) and medium pressure (MP) lamps in the presence of bromide was investigated in the present study. The UV/chlorine process significantly enhanced bromate formation as compared to dark chlorination. The bromate formation was elevated with increasing UV fluence, bromide concentration, and pH values under both LP and MP UV irradiations. It was significantly enhanced at pH 9 compared to those at pH 6 and 7 with MP UV irradiation, while it was slightly enhanced at pH 9 with LP UV. The formation by UV/chlorine process started with the formation of free bromine (HOBr/OBr - ) through the reaction of chlorine and bromide, followed by a subsequent oxidation of free bromine and formation of BrO and bromate by reacting with radicals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Pd-Pt alloys nanowires as support-less electrocatalyst with high synergistic enhancement in efficiency for methanol oxidation in acidic medium.

    Science.gov (United States)

    Rana, Moumita; Patil, Pramod K; Chhetri, Manjeet; Dileep, K; Datta, Ranjan; Gautam, Ujjal K

    2016-02-01

    In a facile approach, Pd73Pt27 alloy nanowires (NWs) with large aspect ratios were synthesized in high yield by using sacrificial templates. Unlike majority of processes, our synthesis was carried out in aqueous solution with no intermittent separating stages for the products, while maintaining the NW morphology up to ∼30% of Pt. Upon evaporation of their dispersion, the NWs transform into a stable porous membrane due to self-entanglement and can be directly lifted and employed for electrocatalytic applications without external catalyst supports. We show that the NW membranes exhibit efficient electrocatalytic performance for methanol oxidation reaction (MOR) with 10 times higher mass activity and 4.4 times higher specific activity in acidic media as compared to commercial Pt catalysts. The membrane electrocatalysts is robust and exhibited very good stability with retention of ∼70% mass-activity after 4000 potential cycles. Since Pd was found to be inert towards MOR in acidic medium, our investigation provides a direct estimate of synergistic enhancement of efficiency. Over 10 times increment of mass activity appears to be significantly higher than previous investigations in various other reaction media. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. KDM5 interacts with Foxo to modulate cellular levels of oxidative stress.

    Directory of Open Access Journals (Sweden)

    Xingyin Liu

    2014-10-01

    Full Text Available Increased cellular levels of oxidative stress are implicated in a large number of human diseases. Here we describe the transcription co-factor KDM5 (also known as Lid as a new critical regulator of cellular redox state. Moreover, this occurs through a novel KDM5 activity whereby it alters the ability of the transcription factor Foxo to bind to DNA. Our microarray analyses of kdm5 mutants revealed a striking enrichment for genes required to regulate cellular levels of oxidative stress. Consistent with this, loss of kdm5 results in increased sensitivity to treatment with oxidizers, elevated levels of oxidized proteins, and increased mutation load. KDM5 activates oxidative stress resistance genes by interacting with Foxo to facilitate its recruitment to KDM5-Foxo co-regulated genes. Significantly, this occurs independently of KDM5's well-characterized demethylase activity. Instead, KDM5 interacts with the lysine deacetylase HDAC4 to promote Foxo deacetylation, which affects Foxo DNA binding.

  1. Heavy metals induce oxidative stress and trigger oxidative stress-mediated heat shock protein (hsp) modulation in the intertidal copepod Tigriopus japonicus.

    Science.gov (United States)

    Kim, Bo-Mi; Rhee, Jae-Sung; Jeong, Chang-Bum; Seo, Jung Soo; Park, Gyung Soo; Lee, Young-Mi; Lee, Jae-Seong

    2014-11-01

    Heat shock proteins (hsps) are induced by a wide range of environmental stressors including heavy metals in aquatic organisms. However, the effect of heavy metals on zooplankton at the molecular level remains still unclear. In this study, we measured the intracellular reactive oxygen species (ROS) level and the antioxidant enzyme activities for 96 h after exposure to five heavy metals: arsenic (As), cadmium (Cd), copper (Cu), silver (Ag), and zinc (Zn) in the intertidal copepod Tigriopus japonicus. Activities of the antioxidant enzymes were highly elevated in metal-exposed copepods, indicating that heavy metals can induce oxidative stress by generating ROS, and stimulate the involvement of antioxidant enzymes as cellular defense mechanisms. Subsequently, transcriptional changes in hsp gene families were further investigated in the metal-exposed groups for 96 h. The ROS level and glutathione (GSH) content were significantly increased in Ag-, As-, and Cu-exposed copepods, while they were only slightly elevated in Cd- and Zn-exposed groups. Based on the numbers of significantly modulated hsp genes and their expression levels for 96 h, we measured the effect of heavy metals to stress genes of T. japonicus in the following order: Cu > Zn > Ag > As > Cd, implying that Cu acts as a stronger oxidative stress inducer than other heavy metals. Of them, the expression of hsp20 and hsp70 genes was substantially modulated by exposure to heavy metals, indicating that these genes would provide a sensitive molecular biomarker for aquatic monitoring of heavy metal pollution. Copyright © 2014 Elsevier Inc. All rights reserved.

  2. Modulation of soybean lipoxygenase expression and membrane oxidation by water deficit

    NARCIS (Netherlands)

    Vliegenthart, J.F.G.; Maccarrone, M.; Veldink, G.A.; Finazzi Agrò, A.

    1995-01-01

    The modulation of the activity and expression of soybean lipoxygenases 1 (LOX-1) [Vliegenthart, J.F.G. and Veldink, G.A. (1982) in: Free Radicals in Biology (Pryor, W.A., Ed.) pp. 29–64, Academic Press, New York] and 2 (LOX-2) by water deficit (osmotic stress) has been investigated, by following

  3. Baicalin Ameliorates Experimental Liver Cholestasis in Mice by Modulation of Oxidative Stress, Inflammation, and NRF2 Transcription Factor

    Directory of Open Access Journals (Sweden)

    Kezhen Shen

    2017-01-01

    Full Text Available Experimental cholestatic liver fibrosis was performed by bile duct ligation (BDL in mice, and significant liver injury was observed in 15 days. Administration of baicalin in mice significantly ameliorates liver fibrosis. Experimental cholestatic liver fibrosis was associated with induced gene expression of fibrotic markers such as collagen I, fibronectin, alpha smooth muscle actin (SMA, and connective tissue growth factor (CTGF; increased inflammatory cytokines (TNFα, MIP1α, IL1β, and MIP2; increased oxidative stress and reactive oxygen species- (ROS- inducing enzymes (NOX2 and iNOS; dysfunctional mitochondrial electron chain complexes; and apoptotic/necrotic cell death markers (DNA fragmentation, caspase 3 activity, and PARP activity. Baicalin administration on alternate day reduced fibrosis along with profibrotic gene expression, proinflammatory cytokines, oxidative stress, and cell death whereas improving the function of mitochondrial electron transport chain. We observed baicalin enhanced NRF2 activation by nuclear translocation and induced its target genes HO-1 and GCLM, thus enhancing antioxidant defense. Interplay of oxidative stress/inflammation and NRF2 were key players for baicalin-mediated protection. Stellate cell activation is crucial for initiation of fibrosis. Baicalin alleviated stellate cell activation and modulated TIMP1, SMA, collagen 1, and fibronectin in vitro. This study indicates that baicalin might be beneficial for reducing inflammation and fibrosis in liver injury models.

  4. Antifatigue Effects of Antrodia cinnamomea Cultured Mycelium via Modulation of Oxidative Stress Signaling in a Mouse Model

    Directory of Open Access Journals (Sweden)

    Yange Liu

    2017-01-01

    Full Text Available Antrodia cinnamomea, a folk medicinal mushroom, has numerous biological effects. In this study, we aim to assess whether the antifatigue effects of A. cinnamomea mycelia (AC and its underlying mechanisms are related to oxidative stress signaling using behavioral mouse models and biochemical indices detection. Mice were orally treated with AC at doses of 0.1, 0.3, and 0.9 g/kg for three weeks. AC had no effect on the spontaneous activities of mice indicating its safety on central nervous system. Furthermore, results obtained from weight-loaded forced swimming test, rotary rod test, and exhausted running test confirmed that AC significantly enhanced exercise tolerance of mice. Biochemical indices levels showed that these effects were closely correlated with inhibiting the depletion of glycogen and adenosine triphosphate stores, regulating oxidative stress-related parameters (superoxide dismutase, glutathione peroxidase, reactive oxygen species, and malondialdehyde in serum, skeletal muscle, and liver of mice. Moreover, the effects of AC may be related with its regulation on the activations of AMP-activated protein kinase, protein kinase B, and mammalian target of rapamycin in liver and skeletal muscle of mice. Altogether, our data suggest that the antifatigue properties of AC may be one such modulation mechanism via oxidative stress-related signaling in mice.

  5. Watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) juice modulates oxidative damage induced by low dose X-ray in mice.

    Science.gov (United States)

    Mohammad, Mohd Khairul Amran; Mohamed, Muhamad Idham; Zakaria, Ainul Mardhiyah; Abdul Razak, Hairil Rashmizal; Saad, Wan Mazlina Md

    2014-01-01

    Watermelon is a natural product that contains high level of antioxidants and may prevent oxidative damage in tissues due to free radical generation following an exposure to ionizing radiation. The present study aimed to investigate the radioprotective effects of watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) juice against oxidative damage induced by low dose X-ray exposure in mice. Twelve adult male ICR mice were randomly divided into two groups consisting of radiation (Rx) and supplementation (Tx) groups. Rx received filtered tap water, while Tx was supplemented with 50% (v/v) watermelon juice for 28 days ad libitum prior to total body irradiation by 100 μGy X-ray on day 29. Brain, lung, and liver tissues were assessed for the levels of malondialdehyde (MDA), apurinic/apyrimidinic (AP) sites, glutathione (GSH), and superoxide dismutase (SOD) inhibition activities. Results showed significant reduction of MDA levels and AP sites formation of Tx compared to Rx (P watermelon juice restore the intracellular antioxidant activities by significantly increased SOD inhibition activities and GSH levels compared to Rx. These findings may postulate that supplementation of 50% watermelon (Citrullus lanatus (Thunb.) Matsum. and Nakai) juice could modulate oxidative damage induced by low dose X-ray exposure.

  6. Nitric oxide and iron modulate heme oxygenase activity as a long distance signaling response to salt stress in sunflower seedling cotyledons.

    Science.gov (United States)

    Singh, Neha; Bhatla, Satish C

    2016-02-29

     kDa) of HO-1. NaCl-modulated HO-1 activity correlates with endogenous NO content in the cotyledons. Increased NO accumulation by hemin treatment also correlates with enhanced activity of HO-1 in both control and NaCl stress conditions. Present work indicates that NO positively modulates HO-1 activity in sunflower seedling cotyledons. NaCl stress tends to antagonize NO action on HO-1 activity. NO (from sodium nitroprusside; SNP) is probably positively modulating HO-1 activity by way of its interaction/binding with heme group. Present work also shows enhanced NO accumulation in seedling cotyledons both in the absence or presence of iron in the growth medium, in response to NaCl stress. Thus, a probable link between endogenous NO, NaCl stress and iron-homeostasis by way of modulation of HO-1 activity at early stage of sunflower seedling growth has been proposed. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Infusion of Hibiscus sabdariffa L. Modulates Oxidative Stress in Patients with Marfan Syndrome

    Science.gov (United States)

    Soto, María Elena; Zuñiga-Muñoz, Alejandra; Guarner Lans, Verónica; Duran-Hernández, Erendira Janet; Pérez-Torres, Israel

    2016-01-01

    Marfan syndrome (MFS) is associated with progressive aortic dilatation, endothelial dysfunction, and oxidative stress that contribute to the early acute dissection of the vessel and can end up in rupture of the aorta and sudden death. Many studies have described that the organic acids from Hibiscus sabdariffa Linne (HSL) calyces increase cellular antioxidant capacity and decrease oxidative stress. Here we evaluate if the antioxidant properties of HSL infusion improve oxidative stress in MFS patients. Activities of extra cellular super oxide dismutase (ECSOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GSSG-R), glutathione (GSH), lipid peroxidation (LPO) index, total antioxidant capacity (TAC), and ascorbic acid were determined in plasma from MFS patients. Values before and after 3 months of the treatment with 2% HSL infusion were compared in control and MFS subjects. After treatment, there was a significant decrease in ECSOD (p = 0.03), EGPx (p = 0.04), GST (p = 0.03), GSH (p = 0.01), and TAC and ascorbic acid (p = 0.02) but GSSG-R activity (p = 0.04) and LPO (p = 0.02) were increased in MFS patients in comparison to patients receiving the HSL treatment and C subjects. Therefore, the infusion of HSL calyces has antioxidant properties that allow an increase in antioxidant capacity of both the enzymatic and nonenzymatic systems, in the plasma of the MSF patients. PMID:27413258

  8. Infusion of Hibiscus sabdariffa L. Modulates Oxidative Stress in Patients with Marfan Syndrome.

    Science.gov (United States)

    Soto, María Elena; Zuñiga-Muñoz, Alejandra; Guarner Lans, Verónica; Duran-Hernández, Erendira Janet; Pérez-Torres, Israel

    2016-01-01

    Marfan syndrome (MFS) is associated with progressive aortic dilatation, endothelial dysfunction, and oxidative stress that contribute to the early acute dissection of the vessel and can end up in rupture of the aorta and sudden death. Many studies have described that the organic acids from Hibiscus sabdariffa Linne (HSL) calyces increase cellular antioxidant capacity and decrease oxidative stress. Here we evaluate if the antioxidant properties of HSL infusion improve oxidative stress in MFS patients. Activities of extra cellular super oxide dismutase (ECSOD), glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GSSG-R), glutathione (GSH), lipid peroxidation (LPO) index, total antioxidant capacity (TAC), and ascorbic acid were determined in plasma from MFS patients. Values before and after 3 months of the treatment with 2% HSL infusion were compared in control and MFS subjects. After treatment, there was a significant decrease in ECSOD (p = 0.03), EGPx (p = 0.04), GST (p = 0.03), GSH (p = 0.01), and TAC and ascorbic acid (p = 0.02) but GSSG-R activity (p = 0.04) and LPO (p = 0.02) were increased in MFS patients in comparison to patients receiving the HSL treatment and C subjects. Therefore, the infusion of HSL calyces has antioxidant properties that allow an increase in antioxidant capacity of both the enzymatic and nonenzymatic systems, in the plasma of the MSF patients.

  9. Infusion of Hibiscus sabdariffa L. Modulates Oxidative Stress in Patients with Marfan Syndrome

    Directory of Open Access Journals (Sweden)

    María Elena Soto

    2016-01-01

    Full Text Available Marfan syndrome (MFS is associated with progressive aortic dilatation, endothelial dysfunction, and oxidative stress that contribute to the early acute dissection of the vessel and can end up in rupture of the aorta and sudden death. Many studies have described that the organic acids from Hibiscus sabdariffa Linne (HSL calyces increase cellular antioxidant capacity and decrease oxidative stress. Here we evaluate if the antioxidant properties of HSL infusion improve oxidative stress in MFS patients. Activities of extra cellular super oxide dismutase (ECSOD, glutathione peroxidase (GPx, glutathione-S-transferase (GST, glutathione reductase (GSSG-R, glutathione (GSH, lipid peroxidation (LPO index, total antioxidant capacity (TAC, and ascorbic acid were determined in plasma from MFS patients. Values before and after 3 months of the treatment with 2% HSL infusion were compared in control and MFS subjects. After treatment, there was a significant decrease in ECSOD (p=0.03, EGPx (p=0.04, GST (p=0.03, GSH (p=0.01, and TAC and ascorbic acid (p=0.02 but GSSG-R activity (p=0.04 and LPO (p=0.02 were increased in MFS patients in comparison to patients receiving the HSL treatment and C subjects. Therefore, the infusion of HSL calyces has antioxidant properties that allow an increase in antioxidant capacity of both the enzymatic and nonenzymatic systems, in the plasma of the MSF patients.

  10. Modulator effect of watercress against cyclophosphamide-induced oxidative stress in mice

    Directory of Open Access Journals (Sweden)

    Natalia A. Casanova

    2017-06-01

    Full Text Available Watercress (Nasturtium officinale, Cruciferae; W. Aiton is a vegetable widely consumed in our country, with nutritional and potentially chemopreventive properties. Previous reports from our laboratory demonstrated the protective effect of watercress juice against DNA damage induced by cyclophosphamide in vivo. In this study, we evaluated the in vivo effect of cress plant on the oxidative stress in mice. Animals were treated by gavage with different doses of watercress juice (0.5 and 1g/kg body weight for 15 consecutive days before intraperitoneal injection of cyclophosphamide (100 mg/kg body weight. After 24 h, mice were killed by cervical dislocation. The effect of watercress was investigated by assessing the following oxidative stress biomarkers: catalase activity, superoxide dismutase activity, lipid peroxidation, and glutathione balance. Intake of watercress prior to cyclophosphamide administration enhanced superoxide dismutase activity in erythrocytes with no effect on catalase activity. In bone marrow and liver tissues, watercress juice counteracted the effect of cyclophosphamide. Glutathione balance rose by watercress supplementation and lipid oxidation diminished in all matrixes when compared to the respective control groups. Our results support the role of watercress as a diet component with promising properties to be used as health promoter or protective agent against oxidative damage

  11. Synthesis and characterization of new ceramic thermoelectrics implemented in a thermoelectric oxide module

    Czech Academy of Sciences Publication Activity Database

    Tomeš, P.; Robert, R.; Trottmann, M.; Bocher, L.; Aguirre, M.H.; Bitschi, A.; Hejtmánek, Jiří; Weidenkaff, A.

    2010-01-01

    Roč. 39, č. 9 (2010), 1696-1703 ISSN 0361-5235 Institutional research plan: CEZ:AV0Z10100521 Keywords : thermoelectric materials * perovskites * power generation * oxide ceramics * micro-IR camera measurement Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.421, year: 2010

  12. Oxidative stress modulates mitochondrial failure and cyclophilin D function in X-linked adrenoleukodystrophy.

    Science.gov (United States)

    López-Erauskin, Jone; Galino, Jorge; Bianchi, Patrizia; Fourcade, Stéphane; Andreu, Antoni L; Ferrer, Isidre; Muñoz-Pinedo, Cristina; Pujol, Aurora

    2012-12-01

    A common process associated with oxidative stress and severe mitochondrial impairment is the opening of the mitochondrial permeability transition pore, as described in many neurodegenerative diseases. Thus, inhibition of mitochondrial permeability transition pore opening represents a potential target for inhibiting mitochondrial-driven cell death. Among the mitochondrial permeability transition pore components, cyclophilin D is the most studied and has been found increased under pathological conditions. Here, we have used in vitro and in vivo models of X-linked adrenoleukodystrophy to investigate the relationship between the mitochondrial permeability transition pore opening and redox homeostasis. X-linked adrenoleukodystrophy is a neurodegenerative condition caused by loss of function of the peroxisomal ABCD1 transporter, in which oxidative stress plays a pivotal role. In this study, we provide evidence of impaired mitochondrial metabolism in a peroxisomal disease, as fibroblasts in patients with X-linked adrenoleukodystrophy cannot survive when forced to rely on mitochondrial energy production, i.e. on incubation in galactose. Oxidative stress induced under galactose conditions leads to mitochondrial damage in the form of mitochondrial inner membrane potential dissipation, ATP drop and necrotic cell death, together with increased levels of oxidative modifications in cyclophilin D protein. Moreover, we show increased expression levels of cyclophilin D in the affected zones of brains in patients with adrenomyeloneuropathy, in spinal cord of a mouse model of X-linked adrenoleukodystrophy (Abcd1-null mice) and in fibroblasts from patients with X-linked adrenoleukodystrophy. Notably, treatment with antioxidants rescues mitochondrial damage markers in fibroblasts from patients with X-linked adrenoleukodystrophy, including cyclophilin D oxidative modifications, and reverses cyclophilin D induction in vitro and in vivo. These findings provide mechanistic insight into the

  13. Traveling interface modulations and anisotropic front propagation in ammonia oxidation over Rh(110)

    Energy Technology Data Exchange (ETDEWEB)

    Rafti, Matías [Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Fac. Cs. Exactas, Universidad Nacional de La Plata, 64 y Diag. 113 (1900), La Plata (Argentina); Institut für Physikalische Chemie und Elektrochemie, Leibniz-Universität Hannover, Callinstr. 3-3a, D-30167 Hannover (Germany); Borkenhagen, Benjamin; Lilienkamp, Gerhard [Institut für Energieforschung und Physikalische Technologien, Technische Universität Clausthal, Leibnizstr. 4, 38678 Clausthal-Zellerfeld (Germany); Lovis, Florian; Smolinsky, Tim; Imbihl, Ronald, E-mail: imbihl@pci.uni-hannvover.de [Institut für Physikalische Chemie und Elektrochemie, Leibniz-Universität Hannover, Callinstr. 3-3a, D-30167 Hannover (Germany)

    2015-11-14

    The bistable NH{sub 3} + O{sub 2} reaction over a Rh(110) surface was explored in the pressure range 10{sup −6}–10{sup −3} mbar and in the temperature range 300–900 K using photoemission electron microscopy and low energy electron microscopy as spatially resolving methods. We observed a history dependent anisotropy in front propagation, traveling interface modulations, transitions with secondary reaction fronts, and stationary island structures.

  14. The promiscuous enzyme medium-chain 3-keto-acyl-CoA thiolase triggers a vicious cycle in fatty-acid beta-oxidation.

    Directory of Open Access Journals (Sweden)

    Anne-Claire M F Martines

    2017-04-01

    Full Text Available Mitochondrial fatty-acid beta-oxidation (mFAO plays a central role in mammalian energy metabolism. Multiple severe diseases are associated with defects in this pathway. Its kinetic structure is characterized by a complex wiring of which the functional implications have hardly been explored. Repetitive cycles of reversible reactions, each cycle shortening the fatty acid by two carbon atoms, evoke competition between intermediates of different chain lengths for a common set of 'promiscuous' enzymes (enzymes with activity towards multiple substrates. In our validated kinetic model of the pathway, substrate overload causes a steep and detrimental flux decline. Here, we unravel the underlying mechanism and the role of enzyme promiscuity in it. Comparison of alternative model versions elucidated the role of promiscuity of individual enzymes. Promiscuity of the last enzyme of the pathway, medium-chain ketoacyl-CoA thiolase (MCKAT, was both necessary and sufficient to elicit the flux decline. Subsequently, Metabolic Control Analysis revealed that MCKAT had insufficient capacity to cope with high substrate influx. Next, we quantified the internal metabolic regulation, revealing a vicious cycle around MCKAT. Upon substrate overload, MCKAT's ketoacyl-CoA substrates started to accumulate. The unfavourable equilibrium constant of the preceding enzyme, medium/short-chain hydroxyacyl-CoA dehydrogenase, worked as an amplifier, leading to accumulation of upstream CoA esters, including acyl-CoA esters. These acyl-CoA esters are at the same time products of MCKAT and inhibited its already low activity further. Finally, the accumulation of CoA esters led to a sequestration of free CoA. CoA being a cofactor for MCKAT, its sequestration limited the MCKAT activity even further, thus completing the vicious cycle. Since CoA is also a substrate for distant enzymes, it efficiently communicated the 'traffic jam' at MCKAT to the entire pathway. This novel mechanism provides

  15. Involvement of nitrite in the nitrate-mediated modulation of fermentative metabolism and nitric oxide production of soybean roots during hypoxia.

    Science.gov (United States)

    Oliveira, Halley C; Salgado, Ione; Sodek, Ladaslav

    2013-01-01

    It is widely accepted that nitrate but not ammonium improves tolerance of plants to hypoxic stress, although the mechanisms related to this beneficial effect are not well understood. Recently, nitrite derived from nitrate reduction has emerged as the major substrate for the synthesis of nitric oxide (NO), an important signaling molecule in plants. Here, we analyzed the effect of different nitrogen sources (nitrate, nitrite and ammonium) on the metabolic response and NO production of soybean roots under hypoxia. Organic acid analysis showed that root segments isolated from nitrate-cultivated plants presented a lower accumulation of lactate and succinate in response to oxygen deficiency in relation to those from ammonium-cultivated plants. The more pronounced lactate accumulation by root segments of ammonium-grown plants was followed by a higher ethanol release in the medium, evidencing a more intense fermentation under oxygen deficiency than those from nitrate-grown plants. As expected, root segments from nitrate-cultivated plants produced higher amounts of nitrite and NO during hypoxia compared to ammonium cultivation. Exogenous nitrite supplied during hypoxia reduced both ethanol and lactate production and stimulated cyanide-sensitive NO emission by root segments from ammonium-cultivated plants, independent of nitrate. On the other hand, treatments with a NO donor or a NO scavenger did not affect the intensity of fermentation of soybean roots. Overall, these results indicate that nitrite participates in the nitrate-mediated modulation of the fermentative metabolism of soybean roots during oxygen deficiency. The involvement of mitochondrial reduction of nitrite to NO in this mechanism is discussed.

  16. Bacillus amyloliquefaciens SC06 alleviates the oxidative stress of IPEC-1 via modulating Nrf2/Keap1 signaling pathway and decreasing ROS production.

    Science.gov (United States)

    Wang, Yang; Wu, Yanping; Wang, Yibing; Fu, Aikun; Gong, Li; Li, Weifen; Li, Yali

    2017-04-01

    Oxidative stress (OS) plays a major role in the gastrointestinal disorders. Although probiotics were reported to repress OS, few researches compared the antioxidant ability of different Bacillus strains and deciphered the mechanisms. To select a Bacillus strain with higher antioxidant capacity, we used H 2 O 2 to induce intestinal porcine epithelial cell 1 (IPEC-1) OS model. The most suitable H 2 O 2 concentration and incubation time were determined by the half lethal dose and methyl thiazolyl tetrazolium. Correlation analysis was performed to choose a sensitive indicator for OS. As for the comparison of Bacillus, cells were divided into control, Bacillus treatment, H 2 O 2 treatment, and Bacillus pre-protection + H 2 O 2 treatment. Bacillus were co-cultured with IPEC-1 for 3 h in Bacillus and Bacillus pre-protection + H 2 O 2 treatments. Then, based on OS model, 300 μmol/L H 2 O 2 was added into medium of H 2 O 2 and Bacillus pre-protection + H 2 O 2 treatments for another 12 h. Antioxidant and apoptosis gene expressions were detected to screen the target strain. Nuclear factor erythroid-derived 2-related factor 2 (Nrf2)/Kelch-like ECH-associated protein1 (Keap1) pathway, reactive oxygen species (ROS) production, mitochondrial membrane potential (Δψm), apoptosis, and necrosis were analyzed. Results revealed that heme oxygenase-1 (HO-1) gene expression had a positive correlation with H 2 O 2 induction. Moreover, Bacillus amyloliquefaciens SC06 (SC06)-meditated IPEC-1 showed the best antioxidant capacity though modulating Nrf2 phosphorylation. Δψm was elevated, while ROS generation was reduced with SC06 pre-protection, resulting in decreased apoptosis and necrosis. Altogether, HO-1 expression could be regarded as an OS indicator. The regulation of Nrf2/Keap1 pathway and ROS production by SC06 are involved in alleviating OS of IPEC-1.

  17. Oxidative stress modulates the cytokine response of differentiated Th17 and Th1 cells.

    Science.gov (United States)

    Abimannan, Thiruvaimozhi; Peroumal, Doureradjou; Parida, Jyoti R; Barik, Prakash K; Padhan, Prasanta; Devadas, Satish

    2016-10-01

    Reactive oxygen species (ROS) signaling is critical in T helper (Th) cell differentiation; however its role in differentiated Th cell functions is unclear. In this study, we investigated the role of oxidative stress on the effector functions of in vitro differentiated mouse Th17 and Th1 cells or CD4 + T cells from patients with Rheumatoid Arthritis using pro-oxidants plumbagin (PB) and hydrogen peroxide. We found that in mouse Th cells, non-toxic concentration of pro-oxidants inhibited reactivation induced expression of IL-17A in Th17 and IFN-γ in Th1 cells by reducing the expression of their respective TFs, RORγt and T-bet. Interestingly, in both the subsets, PB increased the expression of IL-4 by enhancing reactivation induced ERK1/2 phosphorylation. We further investigated the cytokine modulatory effect of PB on CD4 + T cells isolated from PBMCs of patients with Rheumatoid Arthritis, a well-known Th17 and or Th1 mediated disease. In human CD4 + T cells from Rheumatoid Arthritis patients, PB reduced the frequencies of IL-17A + (Th17), IFN - γ + (Th1) and IL-17A + /IFN - γ + (Th17/1) cells and also inhibited the production of pro-inflammatory cytokines TNF-α and IL-6. N-Acetyl Cysteine (NAC) an antioxidant completely reversed PB mediated cytokine modulatory effects in both mouse and human cells indicating a direct role for ROS. Together our data suggest that oxidative microenvironment can alter cytokine response of terminally differentiated cells and thus altering intracellular ROS could be a potential way to target Th17 and Th1 cells in autoimmune disorders. Copyright © 2016. Published by Elsevier Inc.

  18. Prophylactic Modulation of Methane and Nitrous Oxide Emitted from Ruminants Livestock for Sustainable Animal Agriculture

    OpenAIRE

    J. Takahashi

    2014-01-01

    Major greenhouse gases (GHG) attributed to animal agriculture sector are methane (CH4) and nitrous oxide (N2O), either generated from enteric fermentation or manure. The abatement mechanism of rumen CH4 emission may be divided to direct and indirect suppression to methanogens in the rumen.The most significant strategy to mitigate ruminal CH4 emission in indirect manner is to promote alternative metabolic pathway to dispose of the reducing power, competing with methanogenesis for H2 uptake. Th...

  19. Prophylactic Modulation of Methane and Nitrous Oxide Emitted From Ruminants Livestock for Sustainable Animal Agriculture (REVIEW)

    OpenAIRE

    Takahashi, J

    2014-01-01

    Major greenhouse gases (GHG) attributed to animal agriculture sector are methane (CH4) and nitrous oxide (N2O), either generated from enteric fermentation or manure. The abatement mechanism of rumen CH4 emission may be divided to direct and indirect suppression to methanogens in the rumen.The most significant strategy to mitigate ruminal CH4 emission in indirect manner is to promote alternative metabolic pathway to dispose of the reducing power, competing with methanogenesis for H2 uptake. Th...

  20. Performance Testing of a Photocatalytic Oxidation Module for Spacecraft Cabin Atmosphere Revitalization

    Science.gov (United States)

    Perry, Jay L.; Abney, Morgan B.; Frederick, Kenneth R.; Scott, Joseph P.; Kaiser, Mark; Seminara, Gary; Bershitsky, Alex

    2011-01-01

    Photocatalytic oxidation (PCO) is a candidate process technology for use in high volumetric flow rate trace contaminant control applications in sealed environments. The targeted application for PCO as applied to crewed spacecraft life support system architectures is summarized. Technical challenges characteristic of PCO are considered. Performance testing of a breadboard PCO reactor design for mineralizing polar organic compounds in a spacecraft cabin atmosphere is described. Test results are analyzed and compared to results reported in the literature for comparable PCO reactor designs.

  1. Oxide-based High Temperature Thermoelectric Generators - Development of Integrated Design Technique and Construction of a Thermoelectric Module

    DEFF Research Database (Denmark)

    Wijesooriyage, Waruna Dissanayaka

    development. This thesis is focused on development and optimization of thermoelectric generator (TEG) design techniques for high temperature (> 700 °C) applications. Some of the main targets of this optimization process are to achieve higher volumetric power density (VPD), and reduce the cost-per-Watt. Oxide......In the field of energy management, thermoelectrics are niche candidates for electrical generator devices. For decades, scientists have been focused on thermoelectric (TE) material development. Thus TE module design techniques are still in relatively virgin state when comparing to the TE material...... challenges identified in this project. Thus, the proposed TEG optimizations should address this challenge in an appropriate manner. The work has established a new TEG optimization strategy based on the existing well-known TEG design technique Reduced Current Approach (RCA). This extended version of RCA...

  2. Feeding activity and xenobiotics modulate oxidative status in Daphnia magna: implications for ecotoxicological testing.

    Science.gov (United States)

    Furuhagen, Sara; Liewenborg, Birgitta; Breitholtz, Magnus; Gorokhova, Elena

    2014-11-04

    To apply biomarkers of oxidative stress in laboratory and field settings, an understanding of their responses to changes in physiological rates is important. The evidence is accumulating that caloric intake can increase production of reactive oxygen species and thus affect background variability of oxidative stress biomarkers in ecotoxicological testing. This study aimed to delineate effects of food intake and xenobiotics on oxidative biomarkers in Daphnia magna. Antioxidant capacity measured as oxygen radical absorbance capacity (ORAC) and lipid peroxidation assayed as thiobarbituric acid reactive substances (TBARS) were measured. Food intake was manipulated by varying food densities or by exposing the animals to chemicals inhibiting feeding rate (pharmaceutical haloperidol and pesticide lindane). Feeding rate proved to affect both protein, ORAC, and TBARS in unexposed daphnids. However, there was no significant effect of feeding rate on the protein-specific ORAC values. Both substances affected individual protein and ORAC levels and changed their relationship to feeding rate. Our results show that inhibition of feeding rate influenced the interpretation of biomarker response and further emphasize the importance of understanding (1) baseline variability in potential biomarkers due to variations in metabolic state and (2) the contribution of feeding rate on toxic response of biomarkers.

  3. Green tea polyphenol epigallocatechin-3-gallate differentially modulates oxidative stress in PC12 cell compartments

    International Nuclear Information System (INIS)

    Raza, Haider; John, Annie

    2005-01-01

    Tea polyphenols have been reported to be potent antioxidants and beneficial in oxidative stress related diseases. Prooxidant effects of tea polyphenols have also been reported in cell culture systems. In the present study, we have studied oxidative stress in the subcellular compartments of PC12 cells after treatment with different concentrations of the green tea polyphenol, epigallocatechin-3-gallate (EGCG). We have demonstrated that EGCG has differentially affected the production of reactive oxygen species (ROS), glutathione (GSH) metabolism and cytochrome P450 2E1 activity in the different subcellular compartments in PC12 cells. Our results have shown that although the cell survival was not inhibited by EGCG, there was, however, an increased DNA breakdown and activation of apoptotic markers, caspase 3 and poly- (ADP-ribose) polymerase (PARP) at higher concentrations of EGCG treatment. Our results suggest that the differential effects of EGCG might be related to the alterations in oxidative stress, GSH pools and CYP2E1 activity in different cellular compartments. These results may have implications in determining the chemopreventive therapeutic use of tea polyphenols in vivo

  4. Chronic infusion of lisinopril into hypothalamic paraventricular nucleus modulates cytokines and attenuates oxidative stress in rostral ventrolateral medulla in hypertension

    International Nuclear Information System (INIS)

    Li, Hong-Bao; Qin, Da-Nian; Ma, Le; Miao, Yu-Wang; Zhang, Dong-Mei; Lu, Yan; Song, Xin-Ai; Zhu, Guo-Qing; Kang, Yu-Ming

    2014-01-01

    The hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) play a critical role in the generation and maintenance of sympathetic nerve activity. The renin–angiotensin system (RAS) in the brain is involved in the pathogenesis of hypertension. This study was designed to determine whether inhibition of the angiotensin-converting enzyme (ACE) in the PVN modulates cytokines and attenuates oxidative stress (ROS) in the RVLM, and decreases the blood pressure and sympathetic activity in renovascular hypertensive rats. Renovascular hypertension was induced in male Sprague–Dawley rats by the two-kidney one-clip (2K1C) method. Renovascular hypertensive rats received bilateral PVN infusion with ACE inhibitor lisinopril (LSP, 10 μg/h) or vehicle via osmotic minipump for 4 weeks. Mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA), and plasma proinflammatory cytokines (PICs) were significantly increased in renovascular hypertensive rats. The renovascular hypertensive rats also had higher levels of ACE in the PVN, and lower level of interleukin-10 (IL-10) in the RVLM. In addition, the levels of PICs, the chemokine MCP-1, the subunit of NAD(P)H oxidase (gp91 phox ) and ROS in the RVLM were increased in hypertensive rats. PVN treatment with LSP attenuated those changes occurring in renovascular hypertensive rats. Our findings suggest that the beneficial effects of ACE inhibition in the PVN in renovascular hypertension are partly due to modulation cytokines and attenuation oxidative stress in the RVLM. - Highlights: • Chronic ACE inhibition in PVN on renovascular hypertension was investigated. • 2K1C resulted in sympathoexcitation, increased plasma PICs and hypertension. • 2K1C rats had higher levels of cytokines and reactive oxygen species (ROS) in RVLM. • Chronic inhibiting PVN ACE attenuates cytokines and ROS in RVLM in hypertension

  5. Chronic infusion of lisinopril into hypothalamic paraventricular nucleus modulates cytokines and attenuates oxidative stress in rostral ventrolateral medulla in hypertension

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hong-Bao [Department of Physiology and Pathophysiology, Xi' an Jiaotong University Cardiovascular Research Center, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China); Qin, Da-Nian, E-mail: dnqin@stu.edu.cn [Department of Physiology, Shantou University Medical College, Shantou 515041 (China); Ma, Le [Department of Public Health, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China); Miao, Yu-Wang [Department of Physiology and Pathophysiology, Xi' an Jiaotong University Cardiovascular Research Center, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China); Zhang, Dong-Mei [Department of Physiology, Dalian Medical University, Dalian 116044 (China); Lu, Yan [Department of Clinical Laboratory, Sanaitang Hospital, Lanzhou 730030 (China); Song, Xin-Ai [Department of Physiology and Pathophysiology, Xi' an Jiaotong University Cardiovascular Research Center, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China); Zhu, Guo-Qing [Key Laboratory of Cardiovascular Disease and Molecular Intervention, Department of Physiology, Nanjing Medical University, Nanjing 210029 (China); Kang, Yu-Ming, E-mail: ykang@mail.xjtu.edu.cn [Department of Physiology and Pathophysiology, Xi' an Jiaotong University Cardiovascular Research Center, Xi' an Jiaotong University School of Medicine, Xi' an 710061 (China)

    2014-09-01

    The hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) play a critical role in the generation and maintenance of sympathetic nerve activity. The renin–angiotensin system (RAS) in the brain is involved in the pathogenesis of hypertension. This study was designed to determine whether inhibition of the angiotensin-converting enzyme (ACE) in the PVN modulates cytokines and attenuates oxidative stress (ROS) in the RVLM, and decreases the blood pressure and sympathetic activity in renovascular hypertensive rats. Renovascular hypertension was induced in male Sprague–Dawley rats by the two-kidney one-clip (2K1C) method. Renovascular hypertensive rats received bilateral PVN infusion with ACE inhibitor lisinopril (LSP, 10 μg/h) or vehicle via osmotic minipump for 4 weeks. Mean arterial pressure (MAP), renal sympathetic nerve activity (RSNA), and plasma proinflammatory cytokines (PICs) were significantly increased in renovascular hypertensive rats. The renovascular hypertensive rats also had higher levels of ACE in the PVN, and lower level of interleukin-10 (IL-10) in the RVLM. In addition, the levels of PICs, the chemokine MCP-1, the subunit of NAD(P)H oxidase (gp91{sup phox}) and ROS in the RVLM were increased in hypertensive rats. PVN treatment with LSP attenuated those changes occurring in renovascular hypertensive rats. Our findings suggest that the beneficial effects of ACE inhibition in the PVN in renovascular hypertension are partly due to modulation cytokines and attenuation oxidative stress in the RVLM. - Highlights: • Chronic ACE inhibition in PVN on renovascular hypertension was investigated. • 2K1C resulted in sympathoexcitation, increased plasma PICs and hypertension. • 2K1C rats had higher levels of cytokines and reactive oxygen species (ROS) in RVLM. • Chronic inhibiting PVN ACE attenuates cytokines and ROS in RVLM in hypertension.

  6. Heme oxygenase-1 (HO-1 expression in prostate cancer cells modulates the oxidative response in bone cells.

    Directory of Open Access Journals (Sweden)

    Mercedes Ferrando

    Full Text Available Prostate cancer (PCa is a leading cause of death among males. It is currently estimated that inflammatory responses are linked to 15-20% of all deaths from cancer worldwide. PCa is dominated by complications arising from metastasis to the bone where the tumor cells interact with the bone microenvironment impairing the balance between bone formation and degradation. However, the molecular nature of this interaction is not completely understood. Heme oxygenase-1 (HO-1 counteracts oxidative damage and inflammation. Previous studies from our laboratory showed that HO-1 is implicated in PCa, demonstrating that endogenous HO-1 inhibits bone derived-prostate cancer cells proliferation, invasion and migration and decreases tumor growth and angiogenesis in vivo. The aim of this work was to analyze the impact of HO-1 modulated PCa cells on osteoblasts proliferation in vitro and on bone remodeling in vivo. Using a co-culture system of PC3 cells with primary mice osteoblasts (PMOs, we demonstrated that HO-1 pharmacological induction (hemin treatment abrogated the diminution of PMOs proliferation induced by PCa cells and decreased the expression of osteoclast-modulating factors in osteoblasts. No changes were detected in the expression of genes involved in osteoblasts differentiation. However, co-culture of hemin pre-treated PC3 cells (PC3 Hem with PMOs provoked an oxidative status and activated FoxO signaling in osteoblasts. The percentage of active osteoblasts positive for HO-1 increased in calvarias explants co-cultured with PC3 Hem cells. Nuclear HO-1 expression was detected in tumors generated by in vivo bone injection of HO-1 stable transfected PC3 (PC3HO-1 cells in the femur of SCID mice. These results suggest that HO-1 has the potential to modify the bone microenvironment impacting on PCa bone metastasis.

  7. The effect of carbon monoxide integrating nitric oxide through auxin signal in Arabidopsis to modulate iron deficiency

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    Liming eYang

    2016-03-01

    Full Text Available Carbon monoxide (CO and nitric oxide (NO are essential modulators that regulate the plant response to iron deficiency (-Fe. Auxin is a phytohormone that plays important roles in plant growth and development. We report here that in Arabidopsis –Fe enhanced heme oxygenase-dependent CO generation and auxin transport through redistribution of PIN1 protein, which subsequently increased NO accumulation; NO signaling regulated the activity of ferric chelate reductase (FCR and the expression of Fe-uptake genes including basic helix-loop-helix transcription factor (FIT and the ferric reduction oxidase 2 (FRO2. Over-expression of HY1 encoding heme oxygenase, or treatment with CO donor enhanced basipetal auxin transport, FCR activity, and the expressions of FIT and FRO2 under –Fe. Such effects were compromised in the mutant aux1-7 impaired in auxin transport or in the mutant noa1 or nia1/nia2 defective in NO biosynthesis. -Fe failed to promote auxin transport and FCR activity in hy1 mutant; such inability was reversed in the double mutant of hy1/yucca1 with elevated auxin production, or in hy1/cue1 mutant with NO over-accumulation. Taken together, our results suggest that CO modulates NO signaling through auxin to cope with Fe deficiency in Arabidopsis.

  8. Dynamic Evolution of Nitric Oxide Detoxifying Flavohemoglobins, a Family of Single-Protein Metabolic Modules in Bacteria and Eukaryotes.

    Science.gov (United States)

    Wisecaver, Jennifer H; Alexander, William G; King, Sean B; Hittinger, Chris Todd; Rokas, Antonis

    2016-08-01

    Due to their functional independence, proteins that comprise standalone metabolic units, which we name single-protein metabolic modules, may be particularly prone to gene duplication (GD) and horizontal gene transfer (HGT). Flavohemoglobins (flavoHbs) are prime examples of single-protein metabolic modules, detoxifying nitric oxide (NO), a ubiquitous toxin whose antimicrobial properties many life forms exploit, to nitrate, a common source of nitrogen for organisms. FlavoHbs appear widespread in bacteria and have been identified in a handful of microbial eukaryotes, but how the distribution of this ecologically and biomedically important protein family evolved remains unknown. Reconstruction of the evolutionary history of 3,318 flavoHb protein sequences covering the family's known diversity showed evidence of recurrent HGT at multiple evolutionary scales including intrabacterial HGT, as well as HGT from bacteria to eukaryotes. One of the most striking examples of HGT is the acquisition of a flavoHb by the dandruff- and eczema-causing fungus Malassezia from Corynebacterium Actinobacteria, a transfer that growth experiments show is capable of mediating NO resistance in fungi. Other flavoHbs arose via GD; for example, many filamentous fungi possess two flavoHbs that are differentially targeted to the cytosol and mitochondria, likely conferring protection against external and internal sources of NO, respectively. Because single-protein metabolic modules such as flavoHb function independently, readily undergo GD and HGT, and are frequently involved in organismal defense and competition, we suggest that they represent "plug-and-play" proteins for ecological arms races. © The Author 2016. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  9. Nitric oxide-induced murine hematopoietic stem cell fate involves multiple signaling proteins, gene expression, and redox modulation.

    Science.gov (United States)

    Nogueira-Pedro, Amanda; Dias, Carolina C; Regina, Helena; Segreto, C; Addios, Priscilla C; Lungato, Lisandro; D'Almeida, Vania; Barros, Carlos C; Higa, Elisa M S; Buri, Marcus V; Ferreira, Alice T; Paredes-Gamero, Edgar Julian

    2014-11-01

    There are a growing number of reports showing the influence of redox modulation in cellular signaling. Although the regulation of hematopoiesis by reactive oxygen species (ROS) and reactive nitrogen species (RNS) has been described, their direct participation in the differentiation of hematopoietic stem cells (HSCs) remains unclear. In this work, the direct role of nitric oxide (NO(•)), a RNS, in the modulation of hematopoiesis was investigated using two sources of NO(•) , one produced by endothelial cells stimulated with carbachol in vitro and another using the NO(•)-donor S-nitroso-N-acetyl-D,L-penicillamine (SNAP) in vivo. Two main NO(•) effects were observed: proliferation of HSCs-especially of the short-term HSCs-and its commitment and terminal differentiation to the myeloid lineage. NO(•)-induced proliferation was characterized by the increase in the number of cycling HSCs and hematopoietic progenitor cells positive to BrdU and Ki-67, upregulation of Notch-1, Cx43, PECAM-1, CaR, ERK1/2, Akt, p38, PKC, and c-Myc. NO(•)-induced HSCs differentiation was characterized by the increase in granulocytic-macrophage progenitors, granulocyte-macrophage colony forming units, mature myeloid cells, upregulation of PU.1, and C/EBPα genes concomitantly to the downregulation of GATA-3 and Ikz-3 genes, activation of Stat5 and downregulation of the other analyzed proteins mentioned above. Also, redox status modulation differed between proliferation and differentiation responses, which is likely associated with the transition of the proliferative to differentiation status. Our findings provide evidence of the role of NO(•) in inducing HSCs proliferation and myeloid differentiation involving multiple signaling. © 2014 AlphaMed Press.

  10. Estrogen modulates intestinal mucus physiochemical properties and protects against oxidant injury.

    Science.gov (United States)

    Diebel, Mark E; Diebel, Lawrence N; Manke, Charles W; Liberati, David M

    2015-01-01

    The intestinal epithelial barrier and the intestinal mucus layer may be protective against trauma/hemorrhage shock-induced injury in females. This effect is related to estradiol (E₂) concentrations and varies with the menstrual cycle. We examined the ability of E₂ to impact the physiochemical properties of intestinal mucus and to protect against oxidant-related injury to the mucus and underlying intestinal epithelial barrier in an in vitro model. Non-mucus-producing (HT29) and mucus-producing (HT29-MTX) intestinal epithelial cells (IECs) were exposed to E₂ or no E₂ for 3 days and then grown to confluence on transwell plates. Nonadherent and adherent mucus content was indexed by analysis of mucin using an enzyme-linked immunosorbent assay and mucus viscosity (cp) and elasticity (G') were determined by rheometry. In additional experiments, IEC groups were exposed to hydrogen peroxide and IEC apoptosis as well as permeability (fluorescein isothiocyanate-dextran) and oxidative damage determined by measuring lipid hydroperoxide and protein carbonyl content. There were nearly 50% increases in the mucin content of both the nonadherent and adherent mucus layer(s) in HT29-MTX cells exposed to estrogen. Estrogen treatment also resulted in a twofold and eightfold increase in mucus viscosity and elasticity versus HT29-MTX cells with no estrogen exposure, respectively. Oxygen radical damage to the mucus layer caused by H₂O₂ was significantly reduced by E₂ compared with HT29-MTX + H₂O₂ without estrogen. Estrogen treatment resulted in significant reductions in both apoptosis and permeability seen after H₂O₂ challenge. The results of this study suggest that sex differences in gut barrier function following trauma/hemorrhage shock may in part be related to differences in intestinal mucus content and the resultant physiochemical and oxidant-resistant properties of the mucus layer.

  11. Baicalin Attenuates Alcoholic Liver Injury through Modulation of Hepatic Oxidative Stress, Inflammation and Sonic Hedgehog Pathway in Rats

    Directory of Open Access Journals (Sweden)

    Huifen Wang

    2016-08-01

    Full Text Available Background/Aims: Lipid accumulation, inflammatory responses and oxidative stress have been implicated in the pathology of alcoholic liver disease (ALD. Targeting inhibition of these features may provide a promising therapeutic strategy for ALD. Baicalin, a flavonoid isolated from Scutellaria baicalensis Georgi, has been shown to exert a hepatoprotective effect. However, its effects on ALD remain obscure. This study was aimed to investigate the effects of baicalin on alcohol-induced liver injury and its related mechanisms. Methods: For in vivo experiments, rats were supplied intragastrical administration of alcohol continuously for 4 or 8 weeks, and then received baicalin treatment in the latter 4 weeks in the presence / absence of alcohol intake. Liver histology and function, inflammatory cytokines, oxidative mediators, and the components of the Sonic hedgehog pathway were evaluated. For in vitro experiments, alcohol-stimulated human normal liver cells LO2 were used. Results: Baicalin treatment significantly alleviated alcoholic liver injury, improved liver function impaired by alcohol, and inhibited hepatocytes apoptosis. In addition, baicalin decreased the expression levels of proinflammatory cytokines TNF-α, IL-1β, IL-6 and malonyldialdehyde (MDA, and increased the activities of antioxidant enzymes SOD and GSH-Px. Furthermore, baicalin modulated the activation of Sonic hedgehog (Shh pathway. Administration of baicalin upregulated the expression of sonic hedgehog (Shh, patched (Ptc, Smoothened (Smo, and Glioblastoma-1(Gli-1. Blockade of the Shh pathway in cyclopamine abolished the effects of baicalin in vitro. Conclusion: Both in vivo and in vitro experimental results indicate that baicalin exerts hepatoprotective roles in alcohol-induced liver injury through inhibiting oxidative stress, inflammatory response, and the regulation of the Shh pathway.

  12. Investigation of the direct and indirect electrochemical oxidation of hydrazine in nitric acid medium on platinum; Etude de l`oxydation electrochimique directe et indirecte de l`hydrazine en milieu acide nitrique sur platine

    Energy Technology Data Exchange (ETDEWEB)

    Cames, B

    1997-12-31

    In nuclear fuel processing by the PUREX process, the purification of plutonium in nitric acid medium requires the oxidation of Pu(III) to Pu(IV), and of hydrazinium nitrate to nitrogen. The study helped to characterize the electrochemical behavior of the oxidation of hydrazinium nitrate and the reduction of nitric acid to nitrous acid, a compound which can chemically oxidize hydrazinium nitrate and Pu(III). Electro-analytical studies on polycrystalline platinum showed that hydrazine is oxidized in two potential zones, which depend on the surface texture of the platinum anode. Electrolysis in separate compartments, carried out in medium-acid media (2 and 4 mo/l) in the potential zone where these processes take place, showed that, at 0.9 V/ECS, the hydrazine oxidation reactions involved are: a four-electron process (75 %) with nitrogen formation and a one-electron process (25 %) with formation of nitrogen and ammonium ion. By contrast, electrolysis carried out at 0.65 V/ECS (with reactivation of the electrode at - 0.2 V/ECS to remove the poison from the platinum) allowed the selective oxidation of hydrazine to nitrogen by the four-electron reaction. Nitric acid can only be reduced to nitrous acid in the absence of hydrazine. For medium-acid media ({<=} 6 mol/l), this reaction takes place at potentials below - 0.2 V/ECS. However, the production rate of nitrous acid (partial order 0 with respect to nitric acid) is very low compared with the values obtained for strongly-acid media (6 to 10 mol/l) at the potential of - 0.1 V/ECS. Note that, in concentrated nitric medium, the selectivity of the reduction reaction is 47 to 85 % for nitrous acid, depending on the nitric acid concentration (6 to 10 mol/l) and the potential imposed (- 0.1 {<=} E {<=} 0.6 V/ECS). A kinetic study helped to determine the hydrazine oxidation rates as a function of the operating conditions. In all cases, the reaction rate is of partial order 0 with respect to hydrazine. These studies accordingly

  13. Oxidative stress modulation by Rosmarinus officinalis in CCl4-induced liver cirrhosis.

    Science.gov (United States)

    Gutiérrez, Rosalinda; Alvarado, José L; Presno, Manuel; Pérez-Veyna, Oscar; Serrano, Carmen J; Yahuaca, Patricia

    2010-04-01

    Rosmarinus officinalis (Lamiaceae) possesses antioxidant activity and hepatoprotective effects, and so may provide a possible therapeutic alternative for chronic liver disease. The effect produced by a methanolic extract of Rosmarinus officinalis on CCl(4)-induced liver cirrhosis in rats was investigated using both prevention and reversion models. Over the course of the development of cirrhosis, the increased enzymatic activities of gamma-glutamyl transpeptidase and alanine aminotransferase, and the rise in bilirubin levels caused by CCl(4) administration, were prevented by Rosmarinus officinalis co-administration. When the cirrhosis by oxidative stress was evaluated as an increase on liver lipoperoxidation, total lipid peroxides, nitric oxide in serum, and loss of erythrocyte plasma membrane stability, R. officinalis was shown to prevent such alterations. On cirrhotic animals treated with CCl(4), histological studies showed massive necrosis, periportal inflammation and fibrosis which were modified by R. officinalis. These benefits on experimental cirrhosis suggest a potential therapeutic use for R. officinalis as an alternative for liver cirrhosis. Copyright (c) 2009 John Wiley & Sons, Ltd.

  14. Does Statin Modulate Oxidative Damage Induced by ionizing Radiation in Mouse?

    International Nuclear Information System (INIS)

    Tawfik, S.S.; Zahran, A.M.; Salama, S.F.

    2007-01-01

    HMG-CoA (3-Hydroxy-3-methylglutaryl coenzyme-A) reductase inhibitors commonly referred to as the statins family. The aim of the present work was to evaluate the role of statins on oxidative stress, endothelial function, inflammatory response and bleeding time in gamma irradiated mice. Irradiated mice received 6 Gy y-rays, instilled as 2 fractions (I Gy each/week) for 3 weeks. Treated irradiated animals received by gavage atorvastatin; a synthetic form of statins (10 mg/kg body wt, 3-times/week for 3 weeks) within the same schedule of irradiation. In irradiated mice group, the results revealed significant increases of thiobarbituric acid reactive substances (TBARS), protein carbonyl values, creatine phosphokinase (CPK) activity, C-reactive protein (CRP) level as well as bleeding time. While, there was significant decreases of reduced glutathione (GSH) and nitric oxide (NO) levels, and superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) activities. In treated-irradiated mice group, atorvastatin application has significantly improved the radiation-induced changes in all these tested parameters. It could be concluded that, atorvastatin may be applied to minimize radiation damage and attenuate the side effects of radiotherapy. These results observed in mice need to be confirmed in other experimental models, but could become a part of the rationale of further randomised clinical trails in patients treated by radiotherapy

  15. Modulating indium doped tin oxide electrode properties for laccase electron transfer enhancement

    International Nuclear Information System (INIS)

    Diaconu, Mirela; Chira, Ana; Radu, Lucian

    2014-01-01

    Indium doped tin oxide (ITO) electrodes were functionalized with gold nanoparticles (GNPs) and cysteamine monolayer to enhance the heterogeneous electron transfer process of laccase from Trametes versicolor. The assembly of GNP on ITO support was performed through generation of H + species at the electrode surface by hydroquinone electrooxidation at 0.9 V vs Ag/AgCl. Uniform distribution of gold nanoparticle aggregates on electrode surfaces was confirmed by atomic force microscopy. The size of GNP aggregates was in the range of 200–500 nm. The enhanced charge transfer at the GNP functionalized ITO electrodes was observed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy. Electrocatalytic behavior of laccase immobilized on ITO modified electrode toward oxygen reduction reaction was evaluated using CV in the presence of 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulfuric acid (ABTS). The obtained sigmoidal-shaped voltammograms for ABTS reduction in oxygen saturated buffer solution are characteristic for a catalytic process. The intensity of catalytic current increased linearly with mediator concentration up to 6.2 × 10 −4 M. The registered voltammogram in the absence of ABTS mediator clearly showed a significant faradaic current which is the evidence of the interfacial oxygen reduction. - Highlights: • Assembly of gold nanoparticles on indium tin oxide support at positive potentials • Electrochemical and morphological evaluation of the gold nanoparticle layer assembly • Bioelectrocatalytic oxygen reduction on laccase modified electrode

  16. Modulating indium doped tin oxide electrode properties for laccase electron transfer enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Diaconu, Mirela [National Institute for Biological Sciences, Centre of Bioanalysis, 296 Spl. Independentei, Bucharest 060031 (Romania); Chira, Ana [National Institute for Biological Sciences, Centre of Bioanalysis, 296 Spl. Independentei, Bucharest 060031 (Romania); Politehnica University of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-7 Polizu Str., 011061 (Romania); Radu, Lucian, E-mail: gl_radu@chim.upb.ro [Politehnica University of Bucharest, Faculty of Applied Chemistry and Materials Science, 1-7 Polizu Str., 011061 (Romania)

    2014-08-28

    Indium doped tin oxide (ITO) electrodes were functionalized with gold nanoparticles (GNPs) and cysteamine monolayer to enhance the heterogeneous electron transfer process of laccase from Trametes versicolor. The assembly of GNP on ITO support was performed through generation of H{sup +} species at the electrode surface by hydroquinone electrooxidation at 0.9 V vs Ag/AgCl. Uniform distribution of gold nanoparticle aggregates on electrode surfaces was confirmed by atomic force microscopy. The size of GNP aggregates was in the range of 200–500 nm. The enhanced charge transfer at the GNP functionalized ITO electrodes was observed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy. Electrocatalytic behavior of laccase immobilized on ITO modified electrode toward oxygen reduction reaction was evaluated using CV in the presence of 2,2′-azino-bis 3-ethylbenzothiazoline-6-sulfuric acid (ABTS). The obtained sigmoidal-shaped voltammograms for ABTS reduction in oxygen saturated buffer solution are characteristic for a catalytic process. The intensity of catalytic current increased linearly with mediator concentration up to 6.2 × 10{sup −4} M. The registered voltammogram in the absence of ABTS mediator clearly showed a significant faradaic current which is the evidence of the interfacial oxygen reduction. - Highlights: • Assembly of gold nanoparticles on indium tin oxide support at positive potentials • Electrochemical and morphological evaluation of the gold nanoparticle layer assembly • Bioelectrocatalytic oxygen reduction on laccase modified electrode.

  17. The mammalian circadian clock gene Per2 modulates cell death in response to oxidative stress

    Directory of Open Access Journals (Sweden)

    Maria Chiara Magnone

    2015-01-01

    Full Text Available Living in the earth’s oxygenated environment forced organisms to develop strategies to cope with the damaging effects of molecular oxygen known as reactive oxygen species (ROS. Here we show that Per2, a molecular component of the mammalian circadian clock, is involved in regulating a cell’s response to oxidative stress. Mouse embryonic fibroblasts (MEFs containing a mutation in the Per2 gene are more resistant to cytotoxic effects mediated by ROS than wild type cells which is paralleled by an altered regulation of bcl-2 expression in Per2 mutant MEFs. The elevated survival rate and alteration of NADH/NAD+ ratio in the mutant cells is reversed by introduction of the wild type Per2 gene. Interestingly, clock synchronized cells display a time dependent sensitivity to paraquat, a ROS inducing agent. Our observations indicate that the circadian clock is involved in regulating the fate of a cell to survive or to die in response to oxidative stress, which could have implications for cancer development and the aging process.

  18. The Mammalian circadian clock gene per2 modulates cell death in response to oxidative stress.

    Science.gov (United States)

    Magnone, Maria Chiara; Langmesser, Sonja; Bezdek, April Candice; Tallone, Tiziano; Rusconi, Sandro; Albrecht, Urs

    2014-01-01

    Living in the earth's oxygenated environment forced organisms to develop strategies to cope with the damaging effects of molecular oxygen known as reactive oxygen species (ROS). Here, we show that Per2, a molecular component of the mammalian circadian clock, is involved in regulating a cell's response to oxidative stress. Mouse embryonic fibroblasts (MEFs) containing a mutation in the Per2 gene are more resistant to cytotoxic effects mediated by ROS than wild-type cells, which is paralleled by an altered regulation of bcl-2 expression in Per2 mutant MEFs. The elevated survival rate and alteration of NADH/NAD(+) ratio in the mutant cells is reversed by introduction of the wild-type Per2 gene. Interestingly, clock synchronized cells display a time dependent sensitivity to paraquat, a ROS inducing agent. Our observations indicate that the circadian clock is involved in regulating the fate of a cell to survive or to die in response to oxidative stress, which could have implications for cancer development and the aging process.

  19. Discriminating among different tea leaves using an operating temperature-modulated tin oxide gas sensor

    Science.gov (United States)

    Rastkhadiv, Ali; Jenabi, Amin; Souri, Asma

    2016-03-01

    We report distinguishing different types of tea leaves from each other based on their aroma using a thermal shock-induced generic tin oxide gas sensor. The sensor used in this work consists of a microheater and a tin oxide pellet, both connected to outside circuitry with noble metal contacts. The heater is powered with a series of narrow high magnitude voltage impulses of predetermined thermal impacts adjusted to produce step-like temperature rises of different magnitudes on the gas sensitive pellet. The sensor is exposed to aromas collected from various types of tea leaves at different concentrations. Within 4.5 s, nine 500 ms-wide voltage pulses, each as high as 9.3 V in magnitude, are applied to the microheater. Each pulse causes a step-like temperature jump on the pellet temperature. The transient responses recorded for different tea leaves look different even after amplitude normalization. The sensor profiles are recorded, digitized, and compared with the database of previous experiences. A heuristically defined high dimensional feature vector is automatically generated for each analyte. Classifications are graphically achieved in a 3-D feature space after applying principle component analysis for dimension reduction.

  20. Modulation of oxidative responses by a virulent isolate of Colletotrichum fructicola in apple leaves.

    Science.gov (United States)

    Velho, Aline Cristina; Rockenbach, Mathias F; Mondino, Pedro; Stadnik, Marciel J

    2016-10-01

    Apple bitter rot (ABR) and Glomerella leaf spot (GLS) can be caused by Colletotrichum fructicola. Although both diseases can occur simultaneously in orchards, some isolates show clear organ specialization. Thus, this work was aimed to compare microscopically the development of preinfective structures of ABR- and GLS isolates and their impact on the enzymatic oxidant defense system during the leaf infection process. On leaves, conidial germlings of GLS-isolate formed appressoria mostly sessile. In contrast, those of ABR-isolate were pedicellate and formed multiple melanized appressoria probably as a sign of unsuccessful infection attempts. Neither ABR- nor GLS isolate triggered hypersensitive response in apple leaves. In overall, the activity of scavenging enzymes was higher and long-lasting in leaves inoculated by GLS- than by ABR isolate and control. Guaiacol peroxidase, catalase, and glutathione reductase had activity peaks within 24 h after inoculation (HAI). Ascorbate peroxidase activity was higher only in GLS-infected leaves at 6 HAI, while superoxide dismutase remained unaltered. A lower level of hydrogen peroxide (H2O2) was determined in GLS-infected plants at 48 HAI, but the electrolyte leakage markedly increased. Disease symptoms in leaves were only caused by GLS-isolate. Results suggest that the virulent isolate coordinately downregulates the oxidative plant defense responses enabling its successful establishment in apple leaves. Copyright © 2016 British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  1. Biotransformation of citronellol in rose-oxide using cassava wastewater as a medium Biotransformação de citronelol em óxido de rosa utilizando manipueira como meio de cultura

    Directory of Open Access Journals (Sweden)

    Mário Roberto Maróstica Jr.

    2006-09-01

    Full Text Available The use of liquid cassava waste (manipueira as the medium for the biotransformation of citronellol using a Penicillium sp strain was studied. The strain was able to grow in the waste and production of cellular mass reaching 25 g/L over three days of contact of the spores with the medium. Submerged cultures of Penicillium sp grown in manipueira were able to convert the substrate into cis- and trans-rose oxides when the cells were transferred into a mineral medium for the biotransformation experiments. The production of rose oxide increased by more than 2.4 times using this 2 media process as compared to processes using only a manipueira medium (cassava medium. Auto-oxidation products were not detected in the control experiments.A utilização de resíduo líquido do processamento de mandioca (manipueira como meio de cultura para a biotransformação de citronelol por uma linhagem de Penicillum sp foi estudada. A linhagem foi capaz de se desenvolver na presença do resíduo atingindo produção de massa celular da ordem de 25 g/L durante três dias de contato dos esporos com o meio. Culturas submersas de Penicillium sp desenvolvidas em manipueira foram capazes de converter o substrato a cis- e trans-óxidos de rosa quando as células foram transferidas a um meio mineral. Pôde-se observar que a produção de óxido de rosa sofreu um aumento maior que 2,4 vezes através desse processo em comparação à utilização apenas do meio de manipueira (meio de mandioca. Produtos de auto-oxidação não foram identificados nos experimentos controle.

  2. Modulating the size of ZnO nanorods on SiO2 substrates by incorporating reduced graphene oxide into the seed layer solution

    Directory of Open Access Journals (Sweden)

    Tzu-Yi Yu

    2017-06-01

    Full Text Available In this research, reduced graphene oxide was incorporated into the ZnO seed layer to modulate the rod diameter of ZnO nanorods (NRs during solgel/hydrothermal growth. To characterize the reduced graphene oxide incorporated ZnO NRs, multiple material analysis techniques including field-emission scanning electron microscopy, surface contact angle measurements, X-ray diffraction, and photoluminescence were used to explore distinct properties of these size modulatable NRs. Results indicate ZnO NRs with smaller diameters could be observed with more reduced graphene oxide added into the ZnO seed layer. Furthermore, better crystallinity, higher hydrophobicity and lower defect concentration could be obtained with more amount of reduced graphene oxide added into the ZnO seed layer. The modulatable reduced graphene oxide-incorporated ZnO NRs growth is promising for future ZnO NRs based nanodevice applications.

  3. Natural Biflavonoids Modulate Macrophage–Oxidized LDL Interaction In Vitro and Promote Atheroprotection In Vivo

    Directory of Open Access Journals (Sweden)

    Jorge H. Tabares-Guevara

    2017-08-01

    Full Text Available The accumulation of oxidized ApoB-100-containing lipoproteins in the vascular intima and its subsequent recognition by macrophages results in foam cell formation and inflammation, key events during atherosclerosis development. Agents targeting this process are considered potentially atheroprotective. Since natural biflavonoids exert antioxidant and anti-inflammatory effects, we evaluated the atheroprotective effect of biflavonoids obtained from the tropical fruit tree Garcinia madruno. To this end, the pure biflavonoid aglycones morelloflavone (Mo and volkensiflavone (Vo, as well as the morelloflavone’s glycoside fukugiside (Fu were tested in vitro in primary macrophages, whereas a biflavonoid fraction with defined composition (85% Mo, 10% Vo, and 5% Amentoflavone was tested in vitro and in vivo. All biflavonoid preparations were potent reactive oxygen species (ROS scavengers in the oxygen radical absorbance capacity assay, and most importantly, protected low-density lipoprotein particle from both lipid and protein oxidation. In biflavonoid-treated macrophages, the surface expression of the oxidized LDL (oxLDL receptor CD36 was significantly lower than in vehicle-treated macrophages. Uptake of fluorescently labeled oxLDL and cholesterol accumulation were also attenuated in biflavonoid-treated macrophages and followed a pattern that paralleled that of CD36 surface expression. Fu and Vo inhibited oxLDL-induced ROS production and interleukin (IL-6 secretion, respectively, whereas all aglycones, but not the glucoside Fu, inhibited the secretion of one or more of the cytokines IL-1β, IL-12p70, and monocyte chemotactic protein-1 (MCP-1 in lipopolysaccharide (LPS-stimulated macrophages. Interestingly, in macrophages primed with low-dose LPS and stimulated with cholesterol crystals, IL-1β secretion was significantly and comparably inhibited by all biflavonoid preparations. Intraperitoneal administration of the defined biflavonoid fraction into Apo

  4. Natural Biflavonoids Modulate Macrophage–Oxidized LDL Interaction In Vitro and Promote Atheroprotection In Vivo

    Science.gov (United States)

    Tabares-Guevara, Jorge H.; Lara-Guzmán, Oscar J.; Londoño-Londoño, Julian A.; Sierra, Jelver A.; León-Varela, Yudy M.; Álvarez-Quintero, Rafael M.; Osorio, Edison J.; Ramirez-Pineda, José R.

    2017-01-01

    The accumulation of oxidized ApoB-100-containing lipoproteins in the vascular intima and its subsequent recognition by macrophages results in foam cell formation and inflammation, key events during atherosclerosis development. Agents targeting this process are considered potentially atheroprotective. Since natural biflavonoids exert antioxidant and anti-inflammatory effects, we evaluated the atheroprotective effect of biflavonoids obtained from the tropical fruit tree Garcinia madruno. To this end, the pure biflavonoid aglycones morelloflavone (Mo) and volkensiflavone (Vo), as well as the morelloflavone’s glycoside fukugiside (Fu) were tested in vitro in primary macrophages, whereas a biflavonoid fraction with defined composition (85% Mo, 10% Vo, and 5% Amentoflavone) was tested in vitro and in vivo. All biflavonoid preparations were potent reactive oxygen species (ROS) scavengers in the oxygen radical absorbance capacity assay, and most importantly, protected low-density lipoprotein particle from both lipid and protein oxidation. In biflavonoid-treated macrophages, the surface expression of the oxidized LDL (oxLDL) receptor CD36 was significantly lower than in vehicle-treated macrophages. Uptake of fluorescently labeled oxLDL and cholesterol accumulation were also attenuated in biflavonoid-treated macrophages and followed a pattern that paralleled that of CD36 surface expression. Fu and Vo inhibited oxLDL-induced ROS production and interleukin (IL)-6 secretion, respectively, whereas all aglycones, but not the glucoside Fu, inhibited the secretion of one or more of the cytokines IL-1β, IL-12p70, and monocyte chemotactic protein-1 (MCP-1) in lipopolysaccharide (LPS)-stimulated macrophages. Interestingly, in macrophages primed with low-dose LPS and stimulated with cholesterol crystals, IL-1β secretion was significantly and comparably inhibited by all biflavonoid preparations. Intraperitoneal administration of the defined biflavonoid fraction into ApoE−/− mice

  5. Comparative electrocatalytic oxidation of ethanol, ethylene glycol and glycerol in alkaline medium at Pd-decorated FeCo@Fe/C core-shell nanocatalysts

    CSIR Research Space (South Africa)

    Fashedemi, OO

    2014-05-01

    Full Text Available Electrocatalytic oxidation of alcohols in alkaline solutions is critical for the development of direct alkaline alcohol fuel cells (DAAFCs). This work investigated alcohol oxidation reaction (AOR) at a novel palladium-based core-shell nano catalyst...

  6. In Situ Chemical Synthesis of Fe3O4 Nanoparticles on Reduced Graphene Oxide Sheets in Polyol Medium and Magnetic Properties.

    Science.gov (United States)

    Lee, Jeong Woo; Kim, Jong-Duk

    2015-01-01

    This letter reports the one-pot synthesis of reduced graphene oxide/Fe3O4 composites. By the electrostatic interaction of exfoliated graphene oxide and Fe3+ ions, graphene oxide/Fe3+ ions were prepared in a diethylene glycol. In situ formation of Fe3O4 nanoparticles on graphene oxide sheets and reduction of graphene oxide were then achieved simultaneously by the thermal decomposition reaction of Fe(acac)3 at high temperature. This synthetic method enables control over the phase of Fe3O4 nanoparticles on graphene sheets, further preventing restacking of the graphene sheets and aggregation of Fe3O4 nanoparticles. By controlling the mass ratio of Fe(acac)3 and graphene oxide, a series of reduced graphene oxide/Fe3O4 composites were prepared. Magnetic properties of the reduced graphene oxide/Fe3O4 composites are investigated.

  7. Modulation of lipid metabolism by Centella asiatica in oxidative stress rats.

    Science.gov (United States)

    Hussin, M; Hamid, A A; Mohamad, S; Saari, N; Bakar, F; Dek, S P

    2009-03-01

    A study was carried out to investigate the effects of Centella asiatica leaf on lipid metabolism of oxidative stress rats. The rats were fed 0.1% hydrogen peroxide (H(2)O(2)) with either 0.3% (w/w) C. asiatica extract, 5%C. asiatica powder (w/w), or 0.3% (w/w) alpha-tocopherol for 25 wk. Results of the study showed that C. asiatica powder significantly (P asiatica-fed rats were also found to have significantly (P asiatica extract and powder was found to be significantly (P asiatica significantly decreased body and liver weights of the rats. Histological examinations revealed no obvious changes in all rats studied. Quantitative analysis of C. asiatica leaf revealed high concentration of total phenolic compounds, in particular, catechin, quercetin, and rutin.

  8. Size modulation of nanocrystalline silicon embedded in amorphous silicon oxide by Cat-CVD

    International Nuclear Information System (INIS)

    Matsumoto, Y.; Godavarthi, S.; Ortega, M.; Sanchez, V.; Velumani, S.; Mallick, P.S.

    2011-01-01

    Different issues related to controlling size of nanocrystalline silicon (nc-Si) embedded in hydrogenated amorphous silicon oxide (a-SiO x :H) deposited by catalytic chemical vapor deposition (Cat-CVD) have been reported. Films were deposited using tantalum (Ta) and tungsten (W) filaments and it is observed that films deposited using tantalum filament resulted in good control on the properties. The parameters which can affect the size of nc-Si domains have been studied which include hydrogen flow rate, catalyst and substrate temperatures. The deposited samples are characterized by X-ray diffraction, HRTEM and micro-Raman spectroscopy, for determining the size of the deposited nc-Si. The crystallite formation starts for Ta-catalyst around the temperature of 1700 o C.

  9. Cerium oxide nanozyme modulate the ‘exercise’ redox biology of skeletal muscle

    Science.gov (United States)

    Arya, Aditya; Sethy, Niroj Kumar; Gangwar, Anamika; Bhargava, Neelima; Dubey, Amarish; Roy, Manas; Srivastava, Gaurav; Singh, Sushil Kumar; Das, Mainak; Bhargava, Kalpana

    2017-05-01

    ‘Exercise’ is a double-edged sword for the skeletal muscle. Small amount of ROS generated during mild exercise, is essential for normal force generation; whereas large quantity of ROS generated during intense exercise, may cause contractile dysfunction, resulting in muscle weakness and fatigue. One of the key question in skeletal muscle physiology is ‘could antioxidant therapy improve the skeletal muscle endurance? A question, which has resulted in contradictory experimental findings till this date. This work has addressed this ‘very question’ using a synthetic, inorganic, antioxidant nano-material viz., ‘cerium oxide nanozyme’ (CON). It has been introduced in the rat by intramuscular injection, and the skeletal muscle endurance has been evaluated. Intramuscular injections of CON, concurrent with exercise, enhanced muscle mass, glycogen and ATP content, type I fiber ratio, thus resulting in significantly higher muscle endurance. Electron microscope studies confirmed the presence of CON in the vicinity of muscle mitochondria. There was an increase in the number and size of the muscle mitochondria in the CON treated muscle, following exercise, as compared to the untreated group with only exercised muscle. Quantitative proteomics data and subsequent biological network analysis studies, identified higher levels of oxidative phosphorylation, TCA cycle output and glycolysis in CON supplemented exercised muscle over only exercised muscle. This was further associated with significant increase in the mitochondrial respiratory capacity and muscle contraction, primarily due to higher levels of electron transport chain proteins like NDUFA9, SDHA, ATP5B and ATP5D, which were validated by real-time PCR and western blotting. Along with this, persistence of CON in muscle was evaluated with ICP-MS analysis, which revealed clearance of the particles after 90 d, without exhibiting any inflammation or adverse affects on the health of the experimental animals. Thus a

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

    Directory of Open Access Journals (Sweden)

    Brenner Benjamin

    2009-10-01

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

  11. Hydrogen Gas Is Involved in Auxin-Induced Lateral Root Formation by Modulating Nitric Oxide Synthesis

    Directory of Open Access Journals (Sweden)

    Zeyu Cao

    2017-10-01

    Full Text Available Metabolism of molecular hydrogen (H2 in bacteria and algae has been widely studied, and it has attracted increasing attention in the context of animals and plants. However, the role of endogenous H2 in lateral root (LR formation is still unclear. Here, our results showed that H2-induced lateral root formation is a universal event. Naphthalene-1-acetic acid (NAA; the auxin analog was able to trigger endogenous H2 production in tomato seedlings, and a contrasting response was observed in the presence of N-1-naphthyphthalamic acid (NPA, an auxin transport inhibitor. NPA-triggered the inhibition of H2 production and thereafter lateral root development was rescued by exogenously applied H2. Detection of endogenous nitric oxide (NO by the specific probe 4-amino-5-methylamino-2′,7′-difluorofluorescein diacetate (DAF-FM DA and electron paramagnetic resonance (EPR analyses revealed that the NO level was increased in both NAA- and H2-treated tomato seedlings. Furthermore, NO production and thereafter LR formation induced by auxin and H2 were prevented by 2-4-carboxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO; a specific scavenger of NO and the inhibitor of nitrate reductase (NR; an important NO synthetic enzyme. Molecular evidence confirmed that some representative NO-targeted cell cycle regulatory genes were also induced by H2, but was impaired by the removal of endogenous NO. Genetic evidence suggested that in the presence of H2, Arabidopsis mutants nia2 (in particular and nia1 (two nitrate reductases (NR-defective mutants exhibited defects in lateral root length. Together, these results demonstrated that auxin-induced H2 production was associated with lateral root formation, at least partially via a NR-dependent NO synthesis.

  12. Aluminium induced oxidative stress results in decreased mitochondrial biogenesis via modulation of PGC-1α expression.

    Science.gov (United States)

    Sharma, Deep Raj; Sunkaria, Aditya; Wani, Willayat Yousuf; Sharma, Reeta Kumari; Kandimalla, Ramesh J L; Bal, Amanjit; Gill, Kiran Dip

    2013-12-01

    The present investigation was carried out to elucidate a possible molecular mechanism related to the effects of aluminium-induced oxidative stress on various mitochondrial respiratory complex subunits with special emphasis on the role of Peroxisome proliferator activated receptor gamma co-activator 1α (PGC-1α) and its downstream targets i.e. Nuclear respiratory factor-1(NRF-1), Nuclear respiratory factor-2(NRF-2) and Mitochondrial transcription factor A (Tfam) in mitochondrial biogenesis. Aluminium lactate (10mg/kgb.wt./day) was administered intragastrically to rats for 12 weeks. After 12 weeks of exposure, we found an increase in ROS levels, mitochondrial DNA oxidation and decrease in citrate synthase activity in the Hippocampus (HC) and Corpus striatum (CS) regions of rat brain. On the other hand, there was a decrease in the mRNA levels of the mitochondrial encoded subunits-NADH dehydrogenase (ND) subunits i.e. ND1, ND2, ND3, Cytochrome b (Cytb), Cytochrome oxidase (COX) subunits i.e. COX1, COX3, ATP synthase (ATPase) subunit 6 along with reduced expression of nuclear encoded subunits COX4, COX5A, COX5B of Electron transport chain (ETC). Besides, a decrease in mitochondrial DNA copy number and mitochondrial content in both regions of rat brain was observed. The PGC-1α was down-regulated in aluminium treated rats along with NRF-1, NRF-2 and Tfam, which act downstream from PGC-1α in aluminium treated rats. Electron microscopy results revealed a significant increase in the mitochondrial swelling, loss of cristae, chromatin condensation and decreases in mitochondrial number in case of aluminium treated rats as compared to control. So, PGC-1α seems to be a potent target for aluminium neurotoxicity, which makes it an almost ideal target to control or limit the damage that has been associated with the defective mitochondrial function seen in neurodegenerative diseases. © 2013.

  13. Vitamins D, C, and E in the prevention of type 2 diabetes mellitus: modulation of inflammation and oxidative stress

    Directory of Open Access Journals (Sweden)

    Bibiana Garcia-Bailo

    2011-01-01

    Full Text Available Bibiana Garcia-Bailo1,2, Ahmed El-Sohemy2, Pierre S Haddad3, Paul Arora1,4, Firas BenZaied5, Mohamed Karmali1,2,4, Alaa Badawi11Office for Biotechnology, Genomics and Population Health, Public Health Agency of Canada, Toronto, ON, Canada; 2Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada; 3Natural Health Products and Metabolic Diseases Laboratory, Department of Pharmacology, Université de Montréal and Montreal Diabetes Research Centre, Montreal, QC, Canada; 4Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada; 5Canadian College of Naturopathic Medicine, Toronto, ON, CanadaAbstract: The incidence of type 2 diabetes mellitus (T2DM is increasing worldwide, and certain population subgroups are especially vulnerable to the disease. To reduce T2DM risk and progression at the population level, preventative strategies are needed that can be implemented on a population-wide scale with minimal cost and effort. Chronic low-grade inflammation resulting from oxidative stress and imbalances in the innate immune system has been associated with obesity, metabolic syndrome, and insulin resistance – critical stages in the development and progression of T2DM. Therefore, inflammation may play a causal role in the pathogenesis of T2DM, and reducing it via modulation of oxidative stress and the innate immune response could lead to a status of improved insulin sensitivity and delayed disease onset. Dietary supplementation with anti-inflammatory and antioxidant nutritional factors, such as micronutrients, might present a novel strategy toward the prevention and control of T2DM at the population level. This review examines current knowledge linking oxidation, inflammatory signaling pathways, and vitamin supplementation or intake to the risk of T2DM. The concept that micronutrients, via attenuation of inflammation, could be employed as a novel preventive measure for T2DM is evaluated in the context of its

  14. Huntington's disease induced cardiac amyloidosis is reversed by modulating protein folding and oxidative stress pathways in the Drosophila heart.

    Science.gov (United States)

    Melkani, Girish C; Trujillo, Adriana S; Ramos, Raul; Bodmer, Rolf; Bernstein, Sanford I; Ocorr, Karen

    2013-01-01

    contractile proteins, leads to mitochondrial dysfunction and increases oxidative stress in cardiomyocytes leading to abnormal cardiac function. We conclude that modulation of both protein unfolding and oxidative stress pathways in the Drosophila heart model can ameliorate the detrimental PolyQ effects, thus providing unique insights into the genetic mechanisms underlying amyloid-induced cardiac failure in HD patients.

  15. Estresse oxidativo: conceito, implicações e fatores modulatórios Oxidative stress: concept, implications and modulating factors

    Directory of Open Access Journals (Sweden)

    Kiriaque Barra Ferreira Barbosa

    2010-08-01

    relevant agents of the antioxidant defense system on the biomarkers of oxidative stress. The main exogenous factors that modulate oxidative stress will also be discussed.

  16. Aluminium induced oxidative stress results in decreased mitochondrial biogenesis via modulation of PGC-1α expression

    International Nuclear Information System (INIS)

    Sharma, Deep Raj; Sunkaria, Aditya; Wani, Willayat Yousuf; Sharma, Reeta Kumari; Kandimalla, Ramesh J.L.; Bal, Amanjit; Gill, Kiran Dip

    2013-01-01

    The present investigation was carried out to elucidate a possible molecular mechanism related to the effects of aluminium-induced oxidative stress on various mitochondrial respiratory complex subunits with special emphasis on the role of Peroxisome proliferator activated receptor gamma co-activator 1α (PGC-1α) and its downstream targets i.e. Nuclear respiratory factor-1(NRF-1), Nuclear respiratory factor-2(NRF-2) and Mitochondrial transcription factor A (Tfam) in mitochondrial biogenesis. Aluminium lactate (10 mg/kg b.wt./day) was administered intragastrically to rats for 12 weeks. After 12 weeks of exposure, we found an increase in ROS levels, mitochondrial DNA oxidation and decrease in citrate synthase activity in the Hippocampus (HC) and Corpus striatum (CS) regions of rat brain. On the other hand, there was a decrease in the mRNA levels of the mitochondrial encoded subunits–NADH dehydrogenase (ND) subunits i.e. ND1, ND2, ND3, Cytochrome b (Cytb), Cytochrome oxidase (COX) subunits i.e. COX1, COX3, ATP synthase (ATPase) subunit 6 along with reduced expression of nuclear encoded subunits COX4, COX5A, COX5B of Electron transport chain (ETC). Besides, a decrease in mitochondrial DNA copy number and mitochondrial content in both regions of rat brain was observed. The PGC-1α was down-regulated in aluminium treated rats along with NRF-1, NRF-2 and Tfam, which act downstream from PGC-1α in aluminium treated rats. Electron microscopy results revealed a significant increase in the mitochondrial swelling, loss of cristae, chromatin condensation and decreases in mitochondrial number in case of aluminium treated rats as compared to control. So, PGC-1α seems to be a potent target for aluminium neurotoxicity, which makes it an almost ideal target to control or limit the damage that has been associated with the defective mitochondrial function seen in neurodegenerative diseases. - Highlights: • Aluminium decreases the mRNA levels of mitochondrial and nuclear encoded

  17. Aluminium induced oxidative stress results in decreased mitochondrial biogenesis via modulation of PGC-1α expression

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, Deep Raj; Sunkaria, Aditya; Wani, Willayat Yousuf; Sharma, Reeta Kumari; Kandimalla, Ramesh J.L. [Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh 160012 (India); Bal, Amanjit [Department of Histopathology, Postgraduate Institute of Medical Education and Research, Chandigarh (India); Gill, Kiran Dip, E-mail: kdgill2002@yahoo.co.in [Department of Biochemistry, Postgraduate Institute of Medical Education and Research, Chandigarh 160012 (India)

    2013-12-01

    The present investigation was carried out to elucidate a possible molecular mechanism related to the effects of aluminium-induced oxidative stress on various mitochondrial respiratory complex subunits with special emphasis on the role of Peroxisome proliferator activated receptor gamma co-activator 1α (PGC-1α) and its downstream targets i.e. Nuclear respiratory factor-1(NRF-1), Nuclear respiratory factor-2(NRF-2) and Mitochondrial transcription factor A (Tfam) in mitochondrial biogenesis. Aluminium lactate (10 mg/kg b.wt./day) was administered intragastrically to rats for 12 weeks. After 12 weeks of exposure, we found an increase in ROS levels, mitochondrial DNA oxidation and decrease in citrate synthase activity in the Hippocampus (HC) and Corpus striatum (CS) regions of rat brain. On the other hand, there was a decrease in the mRNA levels of the mitochondrial encoded subunits–NADH dehydrogenase (ND) subunits i.e. ND1, ND2, ND3, Cytochrome b (Cytb), Cytochrome oxidase (COX) subunits i.e. COX1, COX3, ATP synthase (ATPase) subunit 6 along with reduced expression of nuclear encoded subunits COX4, COX5A, COX5B of Electron transport chain (ETC). Besides, a decrease in mitochondrial DNA copy number and mitochondrial content in both regions of rat brain was observed. The PGC-1α was down-regulated in aluminium treated rats along with NRF-1, NRF-2 and Tfam, which act downstream from PGC-1α in aluminium treated rats. Electron microscopy results revealed a significant increase in the mitochondrial swelling, loss of cristae, chromatin condensation and decreases in mitochondrial number in case of aluminium treated rats as compared to control. So, PGC-1α seems to be a potent target for aluminium neurotoxicity, which makes it an almost ideal target to control or limit the damage that has been associated with the defective mitochondrial function seen in neurodegenerative diseases. - Highlights: • Aluminium decreases the mRNA levels of mitochondrial and nuclear encoded

  18. Modulation of mesenteric collecting lymphatic contractions by σ1-receptor activation and nitric oxide production.

    Science.gov (United States)

    Trujillo, Andrea N; Katnik, Christopher; Cuevas, Javier; Cha, Byeong Jake; Taylor-Clark, Thomas E; Breslin, Jerome W

    2017-10-01

    Recently, it has been reported that a σ-receptor antagonist could reduce inflammation-induced edema. Lymphatic vessels play an essential role in removing excess interstitial fluid. We tested the hypothesis that activation of σ-receptors would reduce or weaken collecting lymphatic contractions. We used isolated, cannulated rat mesenteric collecting lymphatic vessels to study contractions in response to the σ-receptor agonist afobazole in the absence and presence of different σ-receptor antagonists. We used RT-PCR and Western blot analysis to investigate whether these vessels express the σ 1 -receptor and immunofluorescence confocal microscopy to examine localization of the σ 1 -receptor in the collecting lymphatic wall. Using N -nitro-l-arginine methyl ester (l-NAME) pretreatment before afobazole in isolated lymphatics, we tested the role of nitric oxide (NO) signaling. Finally, we used 4-amino-5-methylamino-2',7'-difluorofluorescein diacetate fluorescence as an indicator to test whether afobazole increases NO release in cultured lymphatic endothelial cells. Our results show that afobazole (50-150 µM) elevated end-systolic diameter and generally reduced pump efficiency and that this response could be partially blocked by the σ 1 -receptor antagonists BD 1047 and BD 1063 but not by the σ 2 -receptor antagonist SM-21. σ 1 -Receptor mRNA and protein were detected in lysates from isolated rat mesenteric collecting lymphatics. Confocal images with anti-σ 1 -receptor antibody labeling suggested localization in the lymphatic endothelium. Blockade of NO synthases with l-NAME inhibited the effects of afobazole. Finally, afobazole elicited increases in NO production from cultured lymphatic endothelial cells. Our findings suggest that the σ 1 -receptor limits collecting lymphatic pumping through a NO-dependent mechanism. NEW & NOTEWORTHY Relatively little is known about the mechanisms that govern contractions of lymphatic vessels. σ 1 -Receptor activation has been

  19. Fullerenol/doxorubicin nanocomposite mitigates acute oxidative stress and modulates apoptosis in myocardial tissue

    Science.gov (United States)

    Seke, Mariana; Petrovic, Danijela; Djordjevic, Aleksandar; Jovic, Danica; Labudovic Borovic, Milica; Kanacki, Zdenko; Jankovic, Milan

    2016-12-01

    Fullerenol (C60(OH)24) is present in aqueous solutions in the form of polyanion nanoparticles with particles’ size distribution within the range from 15 to 42 nm. In this research it is assumed that these features could enable fullerenol nanoparticles (FNPs) to bind positively charged molecules like doxorubicin (DOX) and serve as drug carriers. Considering this, fullerenol/doxorubicin nanocomposite (FNP/DOX) is formed and characterized by ultra-performance liquid chromatography tandem mass spectrometry, dynamic light scattering, atomic force microscopy and transmission electron microscopy. Measurements have shown that DOX did not significantly affect particle size (23 nm). It is also assumed that FNP/DOX could reduce the acute cardiotoxic effects of DOX in vivo (Wistar rats treated i.p.). In this study, quantitative real time polymerase chain reaction results have shown that treatment with DOX alone caused significant increase in mRNA levels of catalase (p effect is significantly reduced by the treatment with FNP/DOX (p < 0.05). Furthermore, mRNA levels of antiapoptotic enzyme (Bcl-2) are significantly increased (p < 0.05) in all treated groups, particularly where FNP/DOX was applied, suggesting cell resistance to apoptosis. Moreover, ultrastructural analysis has shown the absence of myelin figures within the mitochondria in the heart tissue with FNP/DOX treatment, indicating reduction of oxidative stress. Hence, our results have implied that FNP/DOX is generally less harmful to the heart compared to DOX.

  20. [Nutritional approaches to modulate oxidative stress that induce Alzheimer's disease. Nutritional approaches to prevent Alzheimer's disease].

    Science.gov (United States)

    Lara, Humberto Herman; Alanís-Garza, Eduardo Javier; Estrada Puente, María Fernanda; Mureyko, Lucía Liliana; Alarcón Torres, David Alejandro; Ixtepan Turrent, Liliana

    2015-01-01

    Alzheimer's disease is the most common cause of dementia in the world; symptoms first appear after age 65 and have a progressive evolution. Expecting an increase on its incidence and knowing there is currently no cure for Alzheimer's disease, it is a necessity to prevent progression. The change in diet due to globalization may explain the growth of the incidence in places such as Japan and Mediterranean countries, which used to have fewer incidences. There is a direct correlation between disease progression and the increased intake of alcohol, saturated fats, and red meat. Therefore, we find obesity and higher serum levels in cholesterol due to saturated fat as a result. A way to decrease the progression of Alzheimer's is through a diet rich in polipheno/es (potent antioxidants), unsaturated fats (monounsaturated and polyunsaturated), fish, vegetable fa t, fruits with low glycemic index, and a moderate consumption of red wine. Through this potent antioxidant diet we accomplish the prevention of dementia and the progression of Alzheimer's disease. This article emphasizes the food and other components that have been demonstrated to decrease the oxidative stress related to these progressive diseases.

  1. Prophylactic Modulation of Methane and Nitrous Oxide Emitted from Ruminants Livestock for Sustainable Animal Agriculture

    Directory of Open Access Journals (Sweden)

    J. Takahashi

    2014-12-01

    Full Text Available Major greenhouse gases (GHG attributed to animal agriculture sector are methane (CH4 and nitrous oxide (N2O, either generated from enteric fermentation or manure. The abatement mechanism of rumen CH4 emission may be divided to direct and indirect suppression to methanogens in the rumen.The most significant strategy to mitigate ruminal CH4 emission in indirect manner is to promote alternative metabolic pathway to dispose of the reducing power, competing with methanogenesis for H2 uptake. This includes prebiotics and probiotics (mostly propionate enhancers which consume metabolic hydrogen (H2 compete with methanogens and abate rumen methanogenesis in indirect manner. With regard to mitigate GHG emissions from manure, such waste has been proposed as a renewable energy and nitrogen sources through biogas plant. Furthermore, in advanced new biogas system, the ammonia stripping from digested slurry of livestock manure in biogas plant has been examined to apply to nitrogen recycling-options mitigating N2O emission. These options are: (1 ammonolysis on fiber-rich feedstuffs, (2 saccharification of the NH3 treated cellulose biomass to produce bio-ethanol, and (3 reformed hydrogen into NH3 fuel cell to generate electricity with proton exchange membrane fuel cell (PEM.

  2. The nitric oxide-donor molsidomine modulates the innate inflammatory response in a mouse model of muscular dystrophy.

    Science.gov (United States)

    Zordan, Paola; Sciorati, Clara; Campana, Lara; Cottone, Lucia; Clementi, Emilio; Querini, Patrizia-Rovere; Brunelli, Silvia

    2013-09-05

    Inflammation plays a crucial role in muscle remodeling and repair after acute and chronic damage, in particular in muscular dystrophies, a heterogeneous group of genetic diseases leading to muscular degeneration. Defect of nitric oxide (NO) generation is a key pathogenic event in muscular dystrophies, thus NO donors have been explored as new therapeutics for this disease. We have investigated the immune-modulating effect of one of such drugs, molsidomine, able to slow the progression of muscular dystrophy in the α-Sarcoglican-null mice, a model for the limb girdle muscular dystrophy 2D, sharing several hallmarks of muscle degeneration with other muscular dystrophies. α-Sarcoglican-null mice were treated with molsidomine and drug effects on the inflammatory infiltrates and on muscle repair were assessed at selected time points. We found that molsidomine treatment modulates effectively the characteristics of the inflammatory infiltrate within dystrophic muscles, enhancing its healing function. Initially molsidomine amplified macrophage recruitment, promoting a more efficient clearance of cell debris and effective tissue regeneration. At a later stage molsidomine decreased significantly the extent of the inflammatory infiltrate, whose persistence exacerbates muscle damage: most of the remaining macrophages displayed characteristics of the transitional population, associated with reduced fibrosis and increased preservation of the muscle tissue. The dual action of molsidomine, the already known NO donation and the immunomodulatory function we now identified, suggests that it has a unique potential in tissue healing during chronic muscle damage. This, alongside its already approved use in human, makes molsidomine a drug with a significant therapeutic potential in muscular dystrophies. © 2013 Elsevier B.V. All rights reserved.

  3. Organic trace mineral supplementation enhances local and systemic innate immune responses and modulates oxidative stress in broiler chickens.

    Science.gov (United States)

    Echeverry, H; Yitbarek, A; Munyaka, P; Alizadeh, M; Cleaver, A; Camelo-Jaimes, G; Wang, P; O, K; Rodriguez-Lecompte, J C

    2016-03-01

    The effect of organic trace mineral supplementation on performance, intestinal morphology, immune organ weights (bursa of Fabricius and spleen), expression of innate immune response related genes, blood heterophils/lymphocytes ratio, chemical metabolic panel, natural antibodies (IgG), and oxidative stress of broiler chickens was studied. A total of 1,080 day-old male broilers were assigned to 1 of 3 dietary treatments, which included basal diet with Monensin (control), control diet supplemented with bacitracin methylene disalicylate (BMD), and BMD diet supplemented with organic trace minerals (OTM). No difference in feed conversion ratio was observed among treatments; ileum histomorphological analysis showed a lower crypt depth, higher villi height/crypt depth ratio, and lower villi width in the OTM treatment compared to control. Furthermore, OTM treatment resulted in higher uric acid and lower plasma malondehaldehyde (MDA), indicating lower oxidative stress. Gene expression analysis showed that OTM treatment resulted in up-regulations of TLR2 bin the ileum, and TLR2b, TLR4, and IL-12p35 in the bursa of Fabricius, and down-regulation of TLR2b and TLR4 in the cecal tonsils. In the spleen, OTM treatment resulted in up-regulation of IL-10. In conclusion, OTM supplementation to broiler diets may have beneficial effects on intestinal development, immune system status, and survival by improving ileum histomorphological parameters, modulation of Toll-like receptors and anti-inflammatory cytokines, and decreasing level of MDA, which in conjunction could enhance health status. © 2016 Poultry Science Association Inc.

  4. Nitric oxide synthase and cyclooxygenase modulate β-adrenergic cutaneous vasodilatation and sweating in young men.

    Science.gov (United States)

    Fujii, Naoto; McNeely, Brendan D; Kenny, Glen P

    2017-02-15

    β-Adrenergic receptor agonists such as isoproterenol induce cutaneous vasodilatation and sweating in humans, but the mechanisms underpinning this response remain unresolved. Using intradermal microdialysis, we evaluated the roles of nitric oxide synthase (NOS) and cyclooxygenase (COX) in β-adrenergic cutaneous vasodilatation and sweating elicited by administration of isoproterenol. We show that while NOS contributes to β-adrenergic cutaneous vasodilatation, COX restricts cutaneous vasodilatation. We also show that combined inhibition of NOS and COX augments β-adrenergic sweating These new findings advance our basic knowledge regarding the physiological control of cutaneous blood flow and sweating, and provide important and new information to better understand the physiological significance of β-adrenergic receptors in the skin. β-Adrenergic receptor agonists such as isoproterenol can induce cutaneous vasodilatation and sweating in humans, but the mechanisms underpinning this response remain unresolved. We evaluated the hypotheses that (1) nitric oxide synthase (NOS) contributes to β-adrenergic cutaneous vasodilatation, whereas cyclooxygenase (COX) limits the vasodilatation, and (2) COX contributes to β-adrenergic sweating. In 10 young males (25 ± 5 years), cutaneous vascular conductance (CVC) and sweat rate were evaluated at four intradermal forearm skin sites infused with (1) lactated Ringer solution (control), (2) 10 mm N ω -nitro-l-arginine (l-NNA), a non-specific NOS inhibitor, (3) 10 mm ketorolac, a non-specific COX inhibitor, or (4) a combination of l-NNA and ketorolac. All sites were co-administered with a high dose of isoproterenol (100 μm) for 3 min to maximally induce β-adrenergic sweating (β-adrenergic sweating is significantly blunted by subsequent activations). Approximately 60 min after the washout period, three incremental doses of isoproterenol were co-administered (1, 10 and 100 μm each for 25 min). Increases in CVC induced

  5. Prolactin alters blood pressure by modulating the activity of endothelial nitric oxide synthase.

    Science.gov (United States)

    Chang, Albert S; Grant, Ruriko; Tomita, Hirofumi; Kim, Hyung-Suk; Smithies, Oliver; Kakoki, Masao

    2016-11-01

    Increased levels of a cleaved form of prolactin (molecular weight 16 kDa) have been associated with preeclampsia. To study the effects of prolactin on blood pressure (BP), we generated male mice with a single-copy transgene (Tg; inserted into the hypoxanthine-guanine phosphoribosyltransferase locus) that enables inducible hepatic production of prolactin and its cleavage product. The Tg is driven by the indole-3-carbinol (I3C)-inducible rat cytochrome P450 1A1 promoter. When the Tg mice were fed normal chow (NC), plasma prolactin concentrations were comparable to those in female WT mice in the last third of pregnancy, and BP was lower than in WT mice (∼95 mm Hg vs. ∼105 mm Hg). When the Tg mice were fed chow containing IC3, plasma prolactin concentrations increased threefold, BP increased to ∼130 mm Hg, and cardiac function became markedly impaired. IC3 chow did not affect the WT mice. Urinary excretion of nitrite/nitrate and the amount of Ser1177-phosphorylated endothelial nitric oxide (NO) synthase (eNOS) were significantly greater in the Tg mice fed NC than in WT mice, as they are during pregnancy. However, when I3C was fed, these indicators of NO production became significantly less in the Tg mice than in WT mice. The effects of increased plasma prolactin were abolished by a genetic absence of eNOS. Thus, a threefold increase in plasma prolactin is sufficient to increase BP significantly and to markedly impair cardiac function, with effects mediated by NO produced by eNOS. We suggest that pregnant women with abnormally high prolactin levels may need special attention.

  6. Modulation of Protein Metabolism to Mitigate Nitrous Oxide (N2O) Emission from Excreta of Livestock.

    Science.gov (United States)

    Zhao, Guangyong

    2017-01-01

    Dietary protein is the main source of the body needed protein for animals. A great number of domestic animals including cattle, sheep, goats, pigs and chicken and other species are raised in the world to supply meat, milk and eggs that contain high quality of protein for human consumption. Domestic animals consume a great amount of feeds and water and excrete a large amount of faeces and urine. The conversion rate of dietary nitrogen (N, mainly dietary protein) to product N in livestock is low and the amount of N excretion is high and the nitrogenous compounds in excreta can be used as materials for nitrous oxide (N2O) formation in the processes of nitrification and denitrification in storage of excreta. Hence livestock farms and grazing pastures are important sources of N2O. N2O is a potent greenhouse gas and the key factor that damages the ozonosphere of the earth. Therefore, it is urgent to reveal the dietary protein metabolism processes and the regulation mechanism, which will help to reduce N2O emission. The nutritional options to reduce N excretion from livestock and consequently N2O emission include feeding low N rations and supplementing essential amino acid (AA) such as lysine and methionine to balance the AA profile of rations for pigs and ruminants. Other options include regulating partition of N excretion from urine to faeces and urinary nitrogenous constituents by decreasing urea N and increasing hippuric acid in ruminants. Supplementing tannic acid in the ration of ruminants has the potential to decrease the ratio of urinary N/faecal N and regulate the urinary nitrogenous components of ruminants and possibly reduce N2O emission in storage of excreta. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  7. Effect of acute nitric oxide synthase inhibition in the modulation of heart rate in rats

    Directory of Open Access Journals (Sweden)

    A.L. Fellet

    2003-05-01

    Full Text Available Acute nitric oxide synthase inhibition with N G-nitro-L-arginine methyl ester (L-NAME on chronotropic and pressor responses was studied in anesthetized intact rats and rats submitted to partial and complete autonomic blockade. Blood pressure and heart rate were monitored intra-arterially. Intravenous L-NAME injection (7.5 mg/kg elicited the same hypertensive response in intact rats and in rats with partial (ganglionic and parasympathetic blockade and complete autonomic blockade (38 ± 3, 55 ± 6, 54 ± 5, 45 ± 5 mmHg, respectively; N = 9, P = NS. L-NAME-induced bradycardia at the time when blood pressure reached the peak plateau was similar in intact rats and in rats with partial autonomic blockade (43 ± 8, 38 ± 5, 46 ± 6 bpm, respectively; N = 9, P = NS. Rats with combined autonomic blockade showed a tachycardic response to L-NAME (10 ± 3 bpm, P<0.05 vs intact animals, N = 9. Increasing doses of L-NAME (5.0, 7.5 and 10 mg/kg, N = 9 caused a similar increase in blood pressure (45 ± 5, 38 ± 3, 44 ± 9 mmHg, respectively; P = NS and heart rate (31 ± 4, 34 ± 3, 35 ± 4 bpm, respectively; P = NS. Addition of L-NAME (500 µM to isolated atria from rats killed by cervical dislocation and rats previously subjected to complete autonomic blockade did not affect spontaneous beating or contractile strength (N = 9. In vivo results showed that L-NAME promoted a tachycardic response in rats with complete autonomic blockade, whereas the in vitro experiments showed no effect on intrinsic heart rate, suggesting that humoral mechanisms may be involved in the L-NAME-induced cardiac response.

  8. BACTERIAL CLEARANCE IN SEPTIC MICE IS MODULATED BY MCP-1/CCL2 AND NITRIC OXIDE

    Science.gov (United States)

    Gomes, Rachel N.; Teixeira-Cunha, Mariana G. A.; Figueiredo, Rodrigo T.; Almeida, Patricia E.; Alves, Silvio C.; Bozza, Patrícia T.; Bozza, Fernando A.; Bozza, Marcelo T.; Zimmerman, Guy A.; Castro-Faria-Neto, Hugo C.

    2013-01-01

    Bacterial clearance is one of the most important beneficial consequences of the innate immune response. Chemokines are important mediators controlling leukocyte trafficking and activation, whereas reactive oxygen and nitrogen species are effectors in bacterial killing. In the present work, we used in vivo and in vitro models of infections to study the role of monocyte chemoattractant protein 1 (MCP-1)/CCL2 and nitric oxide (NO) in the bacterial clearance in sepsis. Our results show that MCP-1/CCL2 and NO levels are increased in the peritoneal cavity of mice 6 h after sepsis induced by cecal ligation and puncture. Pretreatment with anti–MCP-1/CCL2 monoclonal antibodies increased the number of colony-forming units (CFUs) recovered in the peritoneal lavage fluid. Moreover, CFU counts were increased in the peritoneal fluid of CCR2−/− mice subjected to cecal ligation and puncture. In vitro stimulation of peritoneal macrophages with recombinant MCP-1/CCL2 reduced CFU counts in the supernatant after challenge with Escherichia coli. Conversely, treatment with anti–MCP-1/CCL2 increased CFU counts under the same experimental condition. Stimulation of cultured macrophages with MCP-1/CCL2 and interferon had a synergistic effect on NO production. Macrophages from CCL2−/− mice showed a consistent decrease in NO production when compared with wild-type controls after stimulation with LPS + interferon. Finally, we showed incubation of macrophages with E. coli, and the ERK inhibitor U0126 increased CFU numbers and decreased intracellular levels of NO. In conclusion, we demonstrated for the first time that MCP-1/CCL2 has a crucial role in the clearance of bacteria by mechanisms involving increased expression of inducible NO synthase and production of NO by ERK signaling pathways. PMID:23247123

  9. Nitric Oxide Modulates Postnatal Bone Marrow-Derived Mesenchymal Stem Cell Migration

    Directory of Open Access Journals (Sweden)

    Valarmathi Mani Thiruvanamalai

    2016-11-01

    Full Text Available Nitric oxide (NO is a small free-radical gas molecule, which is highly diffusible and can activate a wide range of downstream effectors, with rapid and widespread cellular effects. NO is a versatile signaling mediator with a plethora of cellular functions. For example, NO has been shown to regulate actin, the microfilament, dependent cellular functions, and also acts as a putative stem cell differentiation-inducing agent. In this study, using a wound-healing model of cellular migration, we have explored the effect of exogenous NO on the kinetics of movement and morphological changes in postnatal bone marrow-derived mesenchymal stem cells (MSCs. Cellular migration kinetics and morphological changes of the migrating MSCs were measured in the presence of an NO donor (S-Nitroso-N-Acetyl-D, L-Penicillamine, SNAP, especially, to track the dynamics of single-cell responses. Two experimental conditions were assessed, in which SNAP (200 µM was applied to the MSCs. In the first experimental group (SN-1, SNAP was applied immediately following wound formation, and migration kinetics was determined for 24 hours. In the second experimental group (SN-2, MSCs were pretreated for 7 days with SNAP prior to wound formation and the determination of migration kinetics. The generated displacement curves were further analyzed by non-linear regression analysis. The migration displacement of the controls and NO treated MSCs (SN-1 and SN-2 were best described by a two parameter exponential functions expressing difference constant coefficients. Additionally, changes in the fractal dimension (D of migrating MSCs were correlated with their displacement kinetics for all the three groups. Overall, these data suggest that NO may evidently function as a stop migration signal by disordering the cytoskeletal elements required for cell movement and proliferation of MSCs.

  10. Hypoxia inducible factor signaling modulates susceptibility to mycobacterial infection via a nitric oxide dependent mechanism.

    Science.gov (United States)

    Elks, Philip M; Brizee, Sabrina; van der Vaart, Michiel; Walmsley, Sarah R; van Eeden, Fredericus J; Renshaw, Stephen A; Meijer, Annemarie H

    2013-01-01

    Tuberculosis is a current major world-health problem, exacerbated by the causative pathogen, Mycobacterium tuberculosis (Mtb), becoming increasingly resistant to conventional antibiotic treatment. Mtb is able to counteract the bactericidal mechanisms of leukocytes to survive intracellularly and develop a niche permissive for proliferation and dissemination. Understanding of the pathogenesis of mycobacterial infections such as tuberculosis (TB) remains limited, especially for early infection and for reactivation of latent infection. Signaling via hypoxia inducible factor α (HIF-α) transcription factors has previously been implicated in leukocyte activation and host defence. We have previously shown that hypoxic signaling via stabilization of Hif-1α prolongs the functionality of leukocytes in the innate immune response to injury. We sought to manipulate Hif-α signaling in a well-established Mycobacterium marinum (Mm) zebrafish model of TB to investigate effects on the host's ability to combat mycobacterial infection. Stabilization of host Hif-1α, both pharmacologically and genetically, at early stages of Mm infection was able to reduce the bacterial burden of infected larvae. Increasing Hif-1α signaling enhanced levels of reactive nitrogen species (RNS) in neutrophils prior to infection and was able to reduce larval mycobacterial burden. Conversely, decreasing Hif-2α signaling enhanced RNS levels and reduced bacterial burden, demonstrating that Hif-1α and Hif-2α have opposing effects on host susceptibility to mycobacterial infection. The antimicrobial effect of Hif-1α stabilization, and Hif-2α reduction, were demonstrated to be dependent on inducible nitric oxide synthase (iNOS) signaling at early stages of infection. Our findings indicate that induction of leukocyte iNOS by stabilizing Hif-1α, or reducing Hif-2α, aids the host during early stages of Mm infection. Stabilization of Hif-1α therefore represents a potential target for therapeutic

  11. Hypoxia inducible factor signaling modulates susceptibility to mycobacterial infection via a nitric oxide dependent mechanism.

    Directory of Open Access Journals (Sweden)

    Philip M Elks

    Full Text Available Tuberculosis is a current major world-health problem, exacerbated by the causative pathogen, Mycobacterium tuberculosis (Mtb, becoming increasingly resistant to conventional antibiotic treatment. Mtb is able to counteract the bactericidal mechanisms of leukocytes to survive intracellularly and develop a niche permissive for proliferation and dissemination. Understanding of the pathogenesis of mycobacterial infections such as tuberculosis (TB remains limited, especially for early infection and for reactivation of latent infection. Signaling via hypoxia inducible factor α (HIF-α transcription factors has previously been implicated in leukocyte activation and host defence. We have previously shown that hypoxic signaling via stabilization of Hif-1α prolongs the functionality of leukocytes in the innate immune response to injury. We sought to manipulate Hif-α signaling in a well-established Mycobacterium marinum (Mm zebrafish model of TB to investigate effects on the host's ability to combat mycobacterial infection. Stabilization of host Hif-1α, both pharmacologically and genetically, at early stages of Mm infection was able to reduce the bacterial burden of infected larvae. Increasing Hif-1α signaling enhanced levels of reactive nitrogen species (RNS in neutrophils prior to infection and was able to reduce larval mycobacterial burden. Conversely, decreasing Hif-2α signaling enhanced RNS levels and reduced bacterial burden, demonstrating that Hif-1α and Hif-2α have opposing effects on host susceptibility to mycobacterial infection. The antimicrobial effect of Hif-1α stabilization, and Hif-2α reduction, were demonstrated to be dependent on inducible nitric oxide synthase (iNOS signaling at early stages of infection. Our findings indicate that induction of leukocyte iNOS by stabilizing Hif-1α, or reducing Hif-2α, aids the host during early stages of Mm infection. Stabilization of Hif-1α therefore represents a potential target for

  12. The Stromal Microenvironment Modulates Mitochondrial Oxidative Phosphorylation in Chronic Lymphocytic Leukemia Cells

    Directory of Open Access Journals (Sweden)

    Hima V. Vangapandu

    2017-10-01

    Full Text Available Peripheral blood chronic lymphocytic leukemia (CLL cells are replicationally quiescent mature B-cells. In short-term cultures, supporting stromal cells provide a survival advantage to CLL cells by inducing transcription and translation without promoting proliferation. We hypothesized that the stromal microenvironment augments malignant B cells' metabolism to enable the cells to cope with their energy demands for transcription and translation. We used extracellular flux analysis to assess the two major energy-generating pathways, mitochondrial oxidative phosphorylation (OxPhos and glycolysis, in primary CLL cells in the presence of three different stromal cell lines. OxPhos, measured as the basal oxygen consumption rate (OCR and maximum respiration capacity, was significantly higher in 28 patients' CLL cells cocultured with bone marrow–derived NK.Tert stromal cells than in CLL cells cultured alone (P = .004 and <.0001, respectively. Similar OCR induction was observed in CLL cells cocultured with M2-10B4 and HS-5 stromal lines. In contrast, heterogeneous changes in the extracellular acidification rate (a measure of glycolysis were observed in CLL cells cocultured with stromal cells. Ingenuity Pathway Analysis of CLL cells' metabolomics profile indicated stroma-mediated stimulation of nucleotide synthesis. Quantitation of ribonucleotide pools showed a significant two-fold increase in CLL cells cocultured with stromal cells, indicating that the stroma may induce CLL cellular bioenergy and the RNA building blocks necessary for the transcriptional requirement of a prosurvival phenotype. The stroma did not impact the proliferation index (Ki-67 staining of CLL cells. Collectively, these data suggest that short-term interaction (≤24 hours with stroma increases OxPhos and bioenergy in replicationally quiescent CLL cells.

  13. [Oxidized low-density lipoprotein modulates differentiation of murine memory CD8+T cell subpopulations].

    Science.gov (United States)

    Zheng, Hua; Lin, Ze-Hang; Zhang, Yan-Mei; Zhou, Chen-Fei; Liu, Xuan; Wu, Sha

    2017-08-20

    To investigate effect of oxidized low-density lipoprotein (ox-LDL) on memory CD8 + T cell subpopulation differentiation in mice with autoimmune diabetes. Cultured splenic CD8 + T cells from pre-diabetic NOD mice isolated with magnetic beads were treated with 30 µg/mL ox-LDL and 10 U/mL interleukin-2 (IL-2) for 24 h and the control cells were treated with IL-2 only. Flow cytometry was used to determine the percentage of splenic CD8 + IFN-γ + T cells, expressions of CD8, CD44 and CD62L on the T cells, and the activation of T cell factor-1 (TCF-1) and STAT-3. The CD127 + memory T cells were purified and transplanted into the pre-diabetic NOD mice via the tail vein, and the blood glucose was recorded weekly and survival time of the mice was monitored. Treatment with ox-LDL significantly reduced islet β cell-specific cytotoxic CD8 + T cells as compared with the control group [(0.7∓0.03)% vs (2.7∓0.14)%, Peffector memory CD8 + T cells (Tem) in the total memory CD8 + T cells was reduced [(10.3∓0.71)% vs (30.3∓1.36)%, Pmemory T cells was significantly increased [(72.3∓3.8)% vs (55.1∓2.61)%, Pmemory T cells in pre-diabetic NOD mice obviously inhibited the increase of blood glucose and prolonged the survival time of the mice (Ptranscriptional factors TCF-1 and phosphorylation of STAT-3, inhibits the formation of effector memory CD8 + T cells with long-term cytotoxicity, but promote the generation of stem cell-like memory CD8 + T cells, which result in suppression of islet β cell-specific effector cytotoxic CD8 + T cell differentiation to lessen autoimmune injury to the islet β cells.

  14. Electrolyte induced rheological modulation of graphene oxide suspensions and its applications in adsorption

    Science.gov (United States)

    Ojha, Abhijeet; Thareja, Prachi

    2018-03-01

    In this study, we report the microstructure, rheology and adsorption characteristics of aqueous suspensions of Graphene Oxide (GO) at a volume fraction (ϕGO) = 0.018, which can be transformed into gels by cation induced charge shielding and cross-linking between GO nanosheets. GO nanosheets of average thickness ∼1.5 nm and a lateral dimension of ∼750 nm are synthesized by Hummer's process. At ϕGO= 0.018, cations of varying size and valence are systematically introduced with electrolytes NH4Cl, LiCl, NaCl, KCl, MgCl2 and FeCl3 at concentrations ranging from 10-5-10-1 M to investigate their effect on the rheology of GO suspensions. Our results suggest that depending on the electrolyte concentration, size and the valence of the cation: low viscosity suspensions, fragile gels and solid-like GO-electrolyte gels are formed. The storage modulus (G') of all GO-electrolyte gels increases with the increase in electrolyte concentration and G' follows the order GO-FeCl3 > GO-MgCl2> GO-KCl > GO-NaCl > GO-LiCl > GO-NH4Cl. FESEM analysis shows that lyophilized GO-electrolyte gels with 10-1 M electrolytes have a porous morphology resulting from the aggregation of GO nanosheets. The GO-electrolyte gels are shown to adsorb high quantities of oils, with GO-FeCl3 gels showing a higher adsorption capacity. The GO-NaCl and GO-FeCl3 lyophilized gels are also shown to adsorb methylene blue dye and follow the pseudo-second-order kinetics of adsorption. Along with higher oil and dye adsorption efficiency, GO-electrolyte gels are easy to recollect after the adsorption, thus avoiding the potential toxicity for bio-organisms in water caused by GO nanosheets.

  15. IL-17A modulates oxidant stress-induced airway hyperresponsiveness but not emphysema.

    Directory of Open Access Journals (Sweden)

    Mariona Pinart

    Full Text Available IL-17A induces the release of pro-inflammatory cytokines and of reactive oxygen species which could lead to neutrophilic inflammation. We determined the role of IL-17 receptor (IL-17R signalling in oxidant-induced lung emphysema and airway hyperresponsiveness. IL-17R(-/- and wild-type C57/BL6 mice were exposed to ozone (3 ppm; 3 hours for 12 times over 6 weeks. Bronchial responsiveness to acetylcholine was measured, and lungs were retrieved. Mean linear intercept (Lm and isometric contractile responses of intrapulmonary airways to acetylcholine were determined. In wild-type mice but not in IL-17R(-/-, chronic ozone exposure caused airway hyperresponsiveness. The increase in Lm after chronic ozone exposure of wild-type mice was also observed in IL-17R(-/- mice. The increased maximal contractile response to acetylcholine seen in airways of wild-type mice exposed to ozone was abolished in IL-17R(-/- mice. p38-mitogen-activated protein kinase (MAPK and dexamethasone-dependent increase in contractile response was reduced in airways from IL-17R(-/- ozone-exposed mice. Lung inflammation scores were not altered in IL-17R(-/- mice exposed to ozone compared to wild-type mice. The increased release of IL-17 and IL-1β, and the activation of p38 MAPK in the lungs of ozone-exposed mice was reduced in IL-17R(-/- mice. IL-17R signalling underlies the increase in airway hyperresponsiveness seen after ozone exposure, mediated by the increased contractility of airway smooth muscle. The emphysema and lung inflammation induced by ozone is not dependent on IL-17.

  16. Glyphosate Adversely Affects Danio rerio Males: Acetylcholinesterase Modulation and Oxidative Stress.

    Science.gov (United States)

    Lopes, Fernanda Moreira; Caldas, Sergiane Souza; Primel, Ednei Gilberto; da Rosa, Carlos Eduardo

    2017-04-01

    It has been demonstrated that glyphosate-based herbicides are toxic to animals. In the present study, reactive oxygen species (ROS) generation, antioxidant capacity against peroxyl radicals (ACAP), and lipid peroxidation (LPO), as well as the activity and expression of the acetylcholinesterase (AChE) enzyme, were evaluated in Danio rerio males exposed to 5 or 10 mg/L of glyphosate for 24 and 96 h. An increase in ACAP in gills after 24 h was observed in the animals exposed to 5 mg/L of glyphosate. A decrease in LPO was observed in brain tissue of animals exposed to 10 mg/L after 24 h, while an increase was observed in muscle after 96 h. No significant alterations were observed in ROS generation. AChE activity was not altered in muscles or brains of animals exposed to either glyphosate concentration for 24 or 96 h. However, gene expression of this enzyme in the brain was reduced after 24 h and was enhanced in both brain and muscle tissues after 96 h. Thus, contrary to previous findings that had attributed the imbalance in the oxidative state of animals exposed to glyphosate-based herbicides to surfactants and other inert compounds, the present study demonstrated that glyphosate per se promotes this same effect in zebrafish males. Although glyphosate concentrations did not alter AChE activity, this study demonstrated for the first time that this molecule affects ache expression in male zebrafish D. rerio.

  17. Oxidative stress modulation by Rosmarinus officinalis in creosote-induced hepatotoxicity.

    Science.gov (United States)

    El-Demerdash, Fatma M; Abbady, Ehab A; Baghdadi, Hoda H

    2016-01-01

    Coal tar is a significant product generated from coal pyrolysis. Coal tar can be utilized as raw materials for various industries. It is also a type of raw material from which phenols, naphthalenes, and anthracene can be extracted. The present study was designed to investigate the possibility of coal tar creosote to induce oxidative stress and biochemical perturbations in rat liver and the role of rosemary (Rosmarinus officinalis) in ameliorating its toxic effects. Male Wister Albino rats were randomly divided into four groups of seven each, group I served as control; group II treated with rosemary (10 mL of water extract/kg BW for 21 days), group III received coal tar creosote (200 mg/4 mL olive oil/kg BW for 3 days), and group IV treated with both rosemary and coal tar creosote. The administration of coal tar creosote significantly caused elevation in lipid peroxidation (LPO) and reduction in the activities of glutathione peroxidase (GPx), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), and glutathione S-transferase (GST). A significant decrease in reduced glutathione (GSH) content was also observed. Liver aminotransferases aspartate transaminase (AST) and alanine transaminase (ALT)] and alkaline phosphatase (AlP) were significantly decreased while lactate dehydrogenase (LDH) was increased. Rosemary pretreatment to coal tar creosote-treated rats decreased LPO level and normalized GPx, GR, SOD, CAT, and GST activities, while GSH content was increased. Also, liver AST, ALT, AlP, and LDH were maintained near normal level due to rosemary treatment. In conclusion, rosemary has beneficial effects and could be able to antagonize coal tar creosote toxicity. © 2014 Wiley Periodicals, Inc.

  18. Preparation and characterization of electrocatalysts based on palladium for electro-oxidation of alcohols in alkaline medium; Preparacao e caracterizacao de eletrocatalisadores a base de paladio para oxidacao eletroquimica de alcoois em meio alcalino

    Energy Technology Data Exchange (ETDEWEB)

    Brandalise, Michele

    2012-07-01

    In this study Pd/C, Au/C, PdAu/C, PdAuPt/C, PdAuBi/C and PdAuIr/C electrocatalysts were prepared by the sodium borohydride reduction method for the electrochemical oxidation of methanol, ethanol and ethylene glycol. This methodology consists in mix an alkaline solution of sodium borohydride to a mixture containing water/isopropyl alcohol, metallic precursors and the Vulcan XC 72 carbon support. The electrocatalysts were characterized by energy dispersive X-ray (EDX), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry. The electrochemical oxidation of the alcohols was studied by chronoamperometry using a thin porous coating technique. The mechanism of ethanol electro-oxidation was studied by Fourier Transformed Infrared (FTIR) in situ. The most effective electrocatalysts were tested in alkaline single cells directly fed with methanol, ethanol or ethylene glycol. Preliminary studies showed that the most suitable atomic composition for preparing the ternary catalysts is 50:45:05. Electrochemical data in alkaline medium show that the electrocatalysts PdAuPt/C (50:45:05) showed the better activity for methanol electro oxidation, while PdAuIr/C was the most active for ethanol oxidation and PdAuBi/C (50:45:05) was the most effective for ethylene glycol oxidation in alkaline medium. These results show that the addition of gold in the composition of electrocatalysts increases their catalytic activities. The spectroelectrochemical FTIR in situ data permitted to conclude that C-C bond is not broken and the acetate is formed. (author)

  19. Nitric Oxide Binds to and Modulates the Activity of a Pollen Specific Arabidopsis Diacylglycerol Kinase

    KAUST Repository

    Wong, Aloysius Tze

    2014-06-01

    Nitric oxide (NO) is an important signaling molecule in plants. In the pollen of Arabidopsis thaliana, NO causes re-orientation of the growing tube and this response is mediated by 3′,5′-cyclic guanosine monophosphate (cGMP). However, in plants, NO-sensors have remained somewhat elusive. Here, the findings of an NO-binding candidate, Arabidopsis thaliana DIACYLGLYCEROL KINASE 4 (ATDGK4; AT5G57690) is presented. In addition to the annotated diacylglycerol kinase domain, this molecule also harbors a predicted heme-NO/oxygen (H-NOX) binding site and a guanylyl cyclase (GC) catalytic domain which have been identified based on the alignment of functionally conserved amino acid residues across species. A 3D model of the molecule was constructed, and from which the locations of the kinase catalytic center, the ATP-binding site, the GC and H-NOX domains were estimated. Docking of ATP to the kinase catalytic center was also modeled. The recombinant ATDGK4 demonstrated kinase activity in vitro, catalyzing the ATP-dependent conversion of sn-1,2-diacylglycerol (DAG) to phosphatidic acid (PA). This activity was inhibited by the mammalian DAG kinase inhibitor R59949 and importantly also by the NO donors diethylamine NONOate (DEA NONOate) and sodium nitroprusside (SNP). Recombinant ATDGK4 also has GC activity in vitro, catalyzing the conversion of guanosine-5\\'-triphosphate (GTP) to cGMP. The catalytic domains of ATDGK4 kinase and GC may be independently regulated since the kinase but not the GC, was inhibited by NO while Ca2+ only stimulates the GC. It is likely that the DAG kinase product, PA, causes the release of Ca2+ from the intracellular stores and Ca2+ in turn activates the GC domain of ATDGK4 through a feedback mechanism. Analysis of publicly available microarray data has revealed that ATDGK4 is highly expressed in the pollen. Here, the pollen tubes of mis-expressing atdgk4 recorded slower growth rates than the wild-type (Col-0) and importantly, they showed altered

  20. Overexpression of HIPK2 attenuates spinal cord injury in rats by modulating apoptosis, oxidative stress, and inflammation.

    Science.gov (United States)

    Li, Renbo; Shang, Jingbo; Zhou, Wei; Jiang, Li; Xie, Donghui; Tu, Guanjun

    2018-04-09

    HIPK2 is considered to be a tumor suppressor. It also has been implicated in several functions such as apoptosis and inflammation that are linked to spinal cord injury (SCI). However, whether HIPK2 ameliorates the neurological pain of SCI remains unclear. Here, we investigated the effects of HIPK2 on neurological function, oxidative stress, levels of inflammatory cytokines and expression of Bcl-2/Bax in an SCI model. Firstly, we evaluated the therapeutic effects of HIPK2 on neurological pain in the SCI rat using the Basso, Beattie and Bresnahan scores and H & E staining. Overexpression of HIPK2 significantly elevated the levels of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF), and reduced the mRNA expression of Nogo-A and RhoA in SCI rats. Furthermore, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assays showed that overexpression of HIPK2 significantly reduced the number of apoptotic cells. Overexpression of HIPK2 also decreased expression of Bax and Caspase-3 and elevated expression of Bcl-2 in the SCI model, indicating that HIPK2 exhibited its protective activity by inhibiting SCI-induced apoptosis. Then, we measured the serum concentrations of malondialdehyde (MDA), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-PX). We also determined the mRNA and protein levels of nuclear factor-κB p65 unit, tumor necrosis factor-α (TNF-α), and interleukin (IL)-1β. HIPK2 overexpression reduced oxidative stress and the levels of inflammatory cytokines compared with SCI control animals. Additionally, acetylation of HIPK2 was reduced in SCI rats. Overexpression of HIPK2 could enhance autophagy by elevating the expression of Beclin-1 and LC3-II while autophagy is regarded as a beneficial regulator to improve spinal cord injury. Together, overexpression of HIPK2 improved contusive SCI induced pain by modulating oxidative stress, Bcl‑2 and Bax signaling, and

  1. Modulation of bacterial ghosts--induced nitric oxide production in macrophages by bacterial ghost-delivered resveratrol.

    Science.gov (United States)

    Koller, Verena J; Dirsch, Verena M; Beres, Hortenzia; Donath, Oliver; Reznicek, Gottfried; Lubitz, Werner; Kudela, Pavol

    2013-03-01

    The present study aimed to investigate the capacity of resveratrol (RV) delivered into macrophages by bacterial ghosts (BGs), representing intact empty nonliving envelopes of Gram-negative bacteria, to modulate nitric oxide (NO) production related to the presence of the pathogen-associated molecular patterns on the surface of BGs. Incubation of the murine macrophage cell line RAW 264.7 with BGs leads to a dose-dependent activation of inducible NO synthase. To modify BG-induced NO formation in RAW 264.7 cells by RV; BGs were loaded with RV (RV-BGs) and incubated with murine macrophages in a dose-dependent manner. RV-BGs delivering RV to the target macrophages significantly reduced BG-induced NO production with concentration of RV more than one order of magnitude lower than the amount of RV capable of reducing NO formation when applied directly. Moreover, no cytotoxic impact of BGs on the viability of RAW 264.7 cells added to macrophages alone or loaded with RV was detected after a mutual 24 h incubation, whereas cell viability slightly decreased (~ 10%) when RV concentrations of 30 μm alone were applied. The results obtained in the present study clearly indicate that the intracellular delivery of RV by BGs significantly enhances the total RV effect. © 2012 The Authors Journal compilation © 2012 FEBS.

  2. Enhancement of heat dissipation of LED module with cupric-oxide composite coating on aluminum-alloy heat sink

    International Nuclear Information System (INIS)

    Kim, Donghyun; Lee, Junghoon; Kim, Junho; Choi, Chang-Hwan; Chung, Wonsub

    2015-01-01

    Highlights: • We fabricate the CuO/resin composite coating layer on aluminum alloy heat sink. • CuO/resin coating considerably improved the surface emissivity. • The LED junction temperature was reduced by CuO/resin coated heat sink. • The thermal resistance of heat sink was decreased by CuO/resin composite coating at 200 μm thickness. - Abstract: A composite coating composed of cupric oxide (CuO) and silicon-based resin was applied to an aluminum-alloy heat sink for a light emitting diode (LED) module. The purpose of the composite coating is to improve the heat dissipation performance of heat sink by enhancing thermal radiation emission. The heat dissipation performance was investigated in terms of LED junction temperature and thermal resistance using a thermal transient method. The CuO and silicon-based resin composite coating showed higher emissivity, and the lower junction temperature and thermal resistance of the heat sink was achieved. In addition, a continuous operation test of the LED chip with the heat sink revealed that the surface treated with the CuO composite coating stably dissipated heat without degradation. In conclusion, the composite coating proposed here showed a significant improvement of the heat dissipation performance of the aluminum-alloy heat sink due to the enhanced thermal radiation property.

  3. Therapeutic implications of curcumin in the prevention of diabetic retinopathy via modulation of anti-oxidant activity and genetic pathways

    Science.gov (United States)

    Aldebasi, Yousef H; Aly, Salah M; Rahmani, Arshad H

    2013-01-01

    Diabetic Retinopathy (DR) is one of the most common complications of diabetes mellitus that affects the blood vessels of the retina, leading to blindness. The current approach of treatment based on anti-inflammatory, anti-angiogenesis drugs and laser photocoagulation are effective but also shows adverse affect in retinal tissues and that can even worsen the visual abilities. Thus, a safe and effective mode of treatment is needed to control or delaying the DR. Based on the earlier evidence of the potentiality of natural products as anti-oxidants, anti-diabetic and antitumor, medicinal plants may constitute a good therapeutic approach in the prevention of DR. Curcumin, constituents of dietary spice turmeric, has been observed to have therapeutic potential in the inhibition or slow down progression of DR. In this review, we summarize the therapeutic potentiality of curcumin in the delaying the DR through antioxidant, anti-inflammatory, inhibition of Vascular Endothelial Growth and nuclear transcription factors. The strength of involvement of curcumin in the modulation of genes action creates a strong optimism towards novel therapeutic strategy of diabetic retinopathy and important mainstay in the management of diabetes and its complications DR. PMID:24379904

  4. Fluid replacement modulates oxidative stress- but not nitric oxide-mediated cutaneous vasodilation and sweating during prolonged exercise in the heat.

    Science.gov (United States)

    McNeely, Brendan D; Meade, Robert D; Fujii, Naoto; Seely, Andrew J E; Sigal, Ronald J; Kenny, Glen P

    2017-12-01

    The roles of nitric oxide synthase (NOS), reactive oxygen species (ROS), and angiotensin II type 1 receptor (AT 1 R) activation in regulating cutaneous vasodilation and sweating during prolonged (≥60 min) exercise are currently unclear. Moreover, it remains to be determined whether fluid replacement (FR) modulates the above thermoeffector responses. To investigate, 11 young men completed 90 min of continuous moderate intensity (46% V̇o 2peak ) cycling performed at a fixed rate of metabolic heat production of 600 W (No FR condition). On a separate day, participants completed a second session of the same protocol while receiving FR to offset sweat losses (FR condition). Cutaneous vascular conductance (CVC) and local sweat rate (LSR) were measured at four intradermal microdialysis forearm sites perfused with: 1 ) lactated Ringer (Control); 2 ) 10 mM N G -nitro-l-arginine methyl ester (l-NAME, NOS inhibition); 3 ) 10 mM ascorbate (nonselective antioxidant); or 4 ) 4.34 nM losartan (AT 1 R inhibition). Relative to Control (71% CVC max at both time points), CVC with ascorbate (80% and 83% CVC max ) was elevated at 60 and 90 min of exercise during FR (both P 0.31). In both conditions, CVC was reduced at end exercise with l-NAME (60% CVC max ; both P 0.19). LSR did not differ between sites in either condition (all P > 0.10). We conclude that NOS regulates cutaneous vasodilation, but not sweating, irrespective of FR, and that ROS influence cutaneous vasodilation during prolonged exercise with FR. Copyright © 2017 the American Physiological Society.

  5. Modulation of Medium-Chain Fatty Acid Synthesis in Synechococcus sp. PCC 7002 by Replacing FabH with a Chaetoceros ketoacyl-ACP synthase

    Directory of Open Access Journals (Sweden)

    Huiya eGu

    2016-05-01

    Full Text Available The isolation or engineering of algal cells synthesizing high levels of medium-chain fatty acids (MCFAs is attractive to mitigate the high clouding point of longer chain fatty acids in algal based biodiesel. To develop a more informed understanding of MCFA synthesis is photosynthetic microorganisms, we isolated several algae from Great Salt Lake and screened this collection for MCFA accumulation to identify strains naturally accumulating high levels of MCFA. A diatom, Chaetoceros sp. GSL56, accumulated particularly high levels of C14 (up to 40%, with the majority of C14 fatty acids (~2/3 allocated in triacylglycerols. Using whole cell transcriptome sequencing and de novo assembly, putative genes encoding fatty acid synthesis enzymes were identified. Enzymes from this Chaetoceros sp. were expressed in the cyanobacterium Synechococcus sp. PCC 7002 to validate gene function and to determine whether eukaryotic enzymes lacking bacteria evolutionary control mechanisms could be used to improve MCFA production in this promising production strains. Replacement of the Synechococcus 7002 native FabH with a Chaetoceros ketoacyl-ACP synthase III increased MCFA synthesis up to five fold. The level of increase is dependent on promoter strength and culturing conditions.

  6. Patients with medium-chain acyl-coenzyme a dehydrogenase deficiency have impaired oxidation of fat during exercise but no effect of L-carnitine supplementation

    DEFF Research Database (Denmark)

    Madsen, K L; Preisler, N; Orngreen, M C

    2013-01-01

    It is not clear to what extent skeletal muscle is affected in patients with medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD). l-Carnitine is commonly used as a supplement in patients with MCADD, although its beneficial effect has not been verified.......It is not clear to what extent skeletal muscle is affected in patients with medium-chain acyl-coenzyme A dehydrogenase deficiency (MCADD). l-Carnitine is commonly used as a supplement in patients with MCADD, although its beneficial effect has not been verified....

  7. A new approach for preparation of magnetite-graphite composite: Intercalation of polyhydroxy iron cation into graphite oxide in L-arginine medium

    Science.gov (United States)

    Li, Shuqiong; Chen, Zhen; Jin, Yongdong; Chen, Shuihua; Wang, Hang; Geng, Junxia; Song, Qiang; Yang, Xiaodan; Ma, Lijian; Li, Shoujian; Qin, Zhi; Zheng, Chong

    2011-05-01

    A new approach to prepare magnetite nanoparticle pillared graphite has been put forward. The magnetic composite was normally obtained by calcining iron-intercalated graphite oxide, but the latter was prepared via intercalation reaction using polyhydroxy iron cation as iron precursor and pillaring agent, and a strong organic guanidine base, L-arginine, as alkaline agent and also intercalating agent. L-arginine, used herein instead of inorganic alkali, which would lead to the deoxygenation and reduction of graphite oxide into graphite, not only provided the alkaline condition for the formation of polyhydroxy iron cations, but also increased the interlayer spacing of graphite oxide to facilitate the intercalation of polyhydroxy iron cations into graphite oxide. The characterization by powder X-ray diffraction, transmission electron microscopy, vibrating sample magnetometer and nitrogen absorption indicated that the composite was nanoscale Fe 3O 4 pillared graphite with superparamagnetic property.

  8. Oxone-mediated oxidative cleavage of β-keto esters and 1,3-diketones to α-keto esters and 1,2-diketones in aqueous medium.

    Science.gov (United States)

    Stergiou, Anastasios; Bariotaki, Anna; Kalaitzakis, Dimitris; Smonou, Ioulia

    2013-07-19

    A versatile and highly efficient method for the direct synthesis of α-keto esters and 1,2-diketones has been developed. This approach utilizes the oxidative cleavage of a variety of β-keto esters and 1,3-diketones mediated by an Oxone/aluminum trichloride system. The simple one-step oxidation reaction proceeded selectively in aqueous media to afford products in high yields, short reaction times, and environmentally benign conditions.

  9. Structure of the oxide film on Ti–6Ta alloy after immersion test in 8 mol/L boiling nitric acid medium

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Dizi, E-mail: diziguo@126.com; Yang, Yingli; Wu, Jinping; Zhao, Bin; Zhao, Hengzhang; Su, Hangbiao; Lu, Yafeng

    2013-08-15

    Highlights: •Structure of the oxide film on Ti–6Ta alloy is studied by depth profile XPS. •TiO{sub 2} and Ta{sub 2}O{sub 5} are found in the top layer of the oxide film. •High valence oxide evolutes form Ti{sub 2}O{sub 3} and TaO. •Shielding effect of Ta{sub 2}O{sub 5} leads to the enhanced corrosion resistance of Ti–Ta alloy. -- Abstract: By using X-ray photoelectron spectroscopy (XPS), X-ray diffractometer (XRD) and scanning electron microscopy (SEM), we investigate the corrosion behavior and the structure of the oxide film of Ti–6Ta alloy that is subjected to the immersion corrosion test in 8 mol/L boiling nitric acid for 432 h. Based on the phase constitution indentified by depth profile XPS, the oxide film could be divided into three sub-layers along its thickness direction: the chemical stable TiO{sub 2} and Ta{sub 2}O{sub 5} are present in layer I; the sub-oxide Ti{sub 2}O{sub 3} and TaO are present in the layer II and layer III, and the high valence oxide evolutes from their sub-oxide gradually. Owing to the shielding effect of Ta{sub 2}O{sub 5}, the corrosion rate of the Ti–6Ta alloy decreases from 0.051 mm/y to 0.014 mm/y with increasing immersion time, showing an excellent corrosion resistance in 8 mol/L boiling nitric acid.

  10. Propham mineralization in aqueous medium by anodic oxidation using boron-doped diamond anode: influence of experimental parameters on degradation kinetics and mineralization efficiency.

    Science.gov (United States)

    Ozcan, Ali; Sahin, Yücel; Koparal, A Savaş; Oturan, Mehmet A

    2008-06-01

    This study aims the removal of a carbamate herbicide, propham, from aqueous solution by direct electrochemical advanced oxidation process using a boron-doped diamond (BDD) anode. This electrode produces large quantities of hydroxyl radicals from oxidation of water, which leads to the oxidative degradation of propham up to its total mineralization. Effect of operational parameters such as current, temperature, pH and supporting electrolyte on the degradation and mineralization rate was studied. The applied current and temperature exert a prominent effect on the total organic carbon (TOC) removal rate of the solutions. The mineralization of propham can be performed at any pH value between 3 and 11 without any loss in oxidation efficiency. The propham decay and its overall mineralization reaction follows a pseudo-first-order kinetics. The apparent rate constant value of propham oxidation was determined as 4.8 x 10(-4)s(-1) at 100 mA and 35 degrees C in the presence of 50mM Na(2)SO(4) in acidic media (pH: 3). A general mineralization sequence was proposed considering the identified oxidation intermediates.

  11. Modulation of cerebral RAGE expression following nitric oxide synthase inhibition in rats subjected to focal cerebral ischemia.

    Science.gov (United States)

    Greco, Rosaria; Demartini, Chiara; Zanaboni, Anna Maria; Blandini, Fabio; Amantea, Diana; Tassorelli, Cristina

    2017-04-05

    The receptor for advanced glycation endproducts (RAGE) is a key mediator of neuroinflammation following cerebral ischemia. Nitric oxide (NO) plays a dualistic role in cerebral ischemia, depending on whether it originates from neuronal, inducible or endothelial synthase. Although a dynamic interplay between RAGE and NO pathways exists, its relevance in ischemic stroke has not been investigated. The aim of this study is to evaluate the effect of the NO synthase (NOS) inhibition on RAGE expression in rats subjected to transient middle cerebral artery occlusion (tMCAo). Full-length (fl-RAGE) gene expression was elevated in the striatum and, to a lesser extent, in the cortex of rats undergone tMCAo. The exacerbation of cortical damage caused by systemic administration of L-N-(1-iminoethyl)ornithine (L-NIO), a relatively selective inhibitor of endothelial NOS (eNOS), was associated with elevated mRNA levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α and fl-RAGE in both the cortex and the striatum. Conversely, NG-nitro-l-arginine methyl ester (L-NAME), a non-selective NOS inhibitor, decreased cortical damage, did not affect cerebral cytokine mRNA levels, while it increased fl-RAGE mRNA expression only in the striatum. Fl-RAGE striatal protein levels varied accordingly with observed mRNA changes in the striatum, while in the cortex, RAGE protein levels were reduced by tMCAo and further decreased following L-NIO treatment. Modulation of RAGE expression by different inhibitors of NOS may have opposite effects on transient cortical ischemia: the non selective inhibition of NOS activity is protective, while the selective inhibition of eNOS is harmful, probably via the activation of inflammatory pathways. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Investigation on the reduction of the oxides of Pd and graphite in alkaline medium and the simultaneous evolution of oxygen reduction reaction and peroxide generation features

    International Nuclear Information System (INIS)

    Kar, Tathagata; Devivaraprasad, Ruttala; Bera, Bapi; Ramesh, Rahul; Neergat, Manoj

    2016-01-01

    Highlights: • Reduction of GO, PdO and parallel evolution of ORR is investigated in 0.1 M KOH. • The results are compared with those of carbon, graphite, c-RGO and Pd. • Peroxide generation and ORR activity increase with reduction of GO to e-RGO. • Peroxide generation decreases and ORR activity increases with reduction of PdO. • Carbon-based materials show peroxide yield of 40–75% as compared to ∼5% with Pd/C. - Abstract: Palladium oxide (PdO) and graphene oxide (GO) are subjected to electrochemical cycling in oxygen-saturated 0.1 M KOH electrolyte in the potential range (−1.2–0.2 V vs. Ag/AgCl (saturated KCl)) relevant to oxygen reduction reaction (ORR). Parallel to ORR, GO and PdO get gradually reduced to graphene and Pd, respectively. With cycling, the half-wave potential of ORR shifts positively with both the oxides. The simultaneous evolution of the peroxide oxidation current on the Pt ring electrode is investigated. On PdO that reduces to Pd, ORR proceeds by the four-electron reduction to OH − and the peroxide oxidation current on the ring electrode decreases with cycling. On the other hand, on GO that reduces to graphene, the ORR proceeds primarily by the two-electron reduction of oxygen and the peroxide oxidation current on the ring electrode increases with cycling. The voltammetric features stabilize with the reduction of the oxides. The ORR and the peroxide oxidation current on the ring electrode with electrochemically reduced GO (e-RGO), chemically reduced GO (c-RGO), carbon-black, and graphite are comparable and they are different from those of the Pd-based precious metal catalyst. The evolution of ORR polarization curves and the peroxide oxidation current on the ring electrode are explained on the basis of the removal of adsorbed-oxygenated species, oxides and by the hydrogen under potential deposition (H upd ) at lower potentials. The results are supported with Koutecky-Levich plots and the voltammograms.

  13. The electro-oxidation of the mixture of formaldehyde and 2-propanol on gold (100 and (111 single crystal planes in alkaline medium

    Directory of Open Access Journals (Sweden)

    BRANISLAV Z. NIKOLIC

    2000-12-01

    Full Text Available The effect of formaldehyde on the oxidation of 2-propanol and vice versa on gold single crystal planes (100 and 111 was studied. An activating effect in the reaction of the simultaneous oxidation of 2-propanol and formaldehyde was obtained on a gold (100 plane. In the case of a gold (111 electrode, the activation effect was not obtained. It was concluded that the adsorption of formaldehyde on the electrode surface prevents the adsorption of poisoning species formed during the electro-oxidation of 2-propanol on the Au(100 plane, while this is not the case on the Au(111 plane. The different behaviour is caused by the difference in the symmetry of the surface atoms of these two Au single-crystal planes.

  14. Biooxidation of n-octane by a recombinant Escherichia coli in a two-liquid-phase system: Effect of medium components on cell growth and alkane oxidation activity

    NARCIS (Netherlands)

    FAVREBULLE, O; Witholt, Bernard

    1992-01-01

    When Escherichia coli hosts are transformed with the alk genes, which encode the alkane oxidation pathway of Pseudomonas oleovorans, the recombinants are capable of converting alkanes to alkanoic acids during growth in two-liquid-phase (aqueous-organic) media. In such media, the cells grow on

  15. Fatty acid beta-oxidation in leukocytes from control subjects and medium-chain acyl-CoA dehydrogenase deficient patients

    NARCIS (Netherlands)

    Wanders, R. J.; IJlst, L.

    1992-01-01

    In recent years an increasing number of inherited diseases in man have been identified in which there is an impairment in mitochondrial fatty acid oxidation. Diagnosis is usually done by gas-chromatographic analysis of urine, which may give difficulties, since urinary abnormalities may only be

  16. Vitamin E-Mediated Modulation of Glutamate Receptor Expression in an Oxidative Stress Model of Neural Cells Derived from Embryonic Stem Cell Cultures

    Directory of Open Access Journals (Sweden)

    Afifah Abd Jalil

    2017-01-01

    Full Text Available Glutamate is the primary excitatory neurotransmitter in the central nervous system. Excessive concentrations of glutamate in the brain can be excitotoxic and cause oxidative stress, which is associated with Alzheimer’s disease. In the present study, the effects of vitamin E in the form of tocotrienol-rich fraction (TRF and alpha-tocopherol (α-TCP in modulating the glutamate receptor and neuron injury markers in an in vitro model of oxidative stress in neural-derived embryonic stem (ES cell cultures were elucidated. A transgenic mouse ES cell line (46C was differentiated into a neural lineage in vitro via induction with retinoic acid. These cells were then subjected to oxidative stress with a significantly high concentration of glutamate. Measurement of reactive oxygen species (ROS was performed after inducing glutamate excitotoxicity, and recovery from this toxicity in response to vitamin E was determined. The gene expression levels of glutamate receptors and neuron-specific enolase were elucidated using real-time PCR. The results reveal that neural cells derived from 46C cells and subjected to oxidative stress exhibit downregulation of NMDA, kainate receptor, and NSE after posttreatment with different concentrations of TRF and α-TCP, a sign of neurorecovery. Treatment of either TRF or α-TCP reduced the levels of ROS in neural cells subjected to glutamate-induced oxidative stress; these results indicated that vitamin E is a potent antioxidant.

  17. Nitric Oxide Orchestrates a Power-Law Modulation of Sympathetic Firing Behaviors in Neonatal Rat Spinal Cords

    Directory of Open Access Journals (Sweden)

    Chun-Kuei Su

    2018-03-01

    Full Text Available Nitric oxide (NO is a diffusible gas and has multifarious effects on both pre- and postsynaptic events. As a consequence of complex excitatory and inhibitory integrations, NO effects on neuronal activities are heterogeneous. Using in vitro preparations of neonatal rats that retain the splanchnic sympathetic nerves and the thoracic spinal cord as an experimental model, we report here that either enhancement or attenuation of NO production in the neonatal rat spinal cords could increase, decrease, or not change the spontaneous firing behaviors recorded from splanchnic sympathetic single fibers. To elucidate the mathematical features of NO-mediated heterogeneous responses, the ratios of changes in firing were plotted against their original firing rates. In log-log plots, a linear data distribution demonstrated that NO-mediated heterogeneity in sympathetic firing responses was well described by a power function. Selective antagonists were applied to test if glycinergic, GABAergic, glutamatergic, and cholinergic neurotransmission in the spinal cord are involved in NO-mediated power-law firing modulations (plFM. NO-mediated plFM diminished in the presence of mecamylamine (an open-channel blocker of nicotinic cholinergic receptors, indicating that endogenous nicotinic receptor activities were essential for plFM. Applications of strychnine (a glycine receptor blocker, gabazine (a GABAA receptor blocker, or kynurenate (a broad-spectrum ionotropic glutamate receptor blocker also caused plFM. However, strychnine- or kynurenate-induced plFM was diminished by L-NAME (an NO synthase inhibitor pretreatments, indicating that the involvements of glycine or ionotropic glutamate receptor activities in plFM were secondary to NO signaling. To recapitulate the arithmetic natures of the plFM, the plFM were simulated by firing changes in two components: a step increment and a fractional reduction of their basal firing activities. Ionotropic glutamate receptor

  18. Nitric Oxide Orchestrates a Power-Law Modulation of Sympathetic Firing Behaviors in Neonatal Rat Spinal Cords.

    Science.gov (United States)

    Su, Chun-Kuei; Chen, Yi-Yin; Ho, Chiu-Ming

    2018-01-01

    Nitric oxide (NO) is a diffusible gas and has multifarious effects on both pre- and postsynaptic events. As a consequence of complex excitatory and inhibitory integrations, NO effects on neuronal activities are heterogeneous. Using in vitro preparations of neonatal rats that retain the splanchnic sympathetic nerves and the thoracic spinal cord as an experimental model, we report here that either enhancement or attenuation of NO production in the neonatal rat spinal cords could increase, decrease, or not change the spontaneous firing behaviors recorded from splanchnic sympathetic single fibers. To elucidate the mathematical features of NO-mediated heterogeneous responses, the ratios of changes in firing were plotted against their original firing rates. In log-log plots, a linear data distribution demonstrated that NO-mediated heterogeneity in sympathetic firing responses was well described by a power function. Selective antagonists were applied to test if glycinergic, GABAergic, glutamatergic, and cholinergic neurotransmission in the spinal cord are involved in NO-mediated power-law firing modulations (plFM). NO-mediated plFM diminished in the presence of mecamylamine (an open-channel blocker of nicotinic cholinergic receptors), indicating that endogenous nicotinic receptor activities were essential for plFM. Applications of strychnine (a glycine receptor blocker), gabazine (a GABA A receptor blocker), or kynurenate (a broad-spectrum ionotropic glutamate receptor blocker) also caused plFM. However, strychnine- or kynurenate-induced plFM was diminished by L-NAME (an NO synthase inhibitor) pretreatments, indicating that the involvements of glycine or ionotropic glutamate receptor activities in plFM were secondary to NO signaling. To recapitulate the arithmetic natures of the plFM, the plFM were simulated by firing changes in two components: a step increment and a fractional reduction of their basal firing activities. Ionotropic glutamate receptor activities were found

  19. Annato extract and β-carotene modulate the production of reactive oxygen species/nitric oxide in neutrophils from diabetic rats

    Science.gov (United States)

    Rossoni-Júnior, Joamyr Victor; Araújo, Glaucy Rodrigues; Pádua, Bruno da Cruz; Chaves, Míriam Martins; Pedrosa, Maria Lúcia; Silva, Marcelo Eustáquio; Costa, Daniela Caldeira

    2012-01-01

    Annatto has been identified as carotenoids that have antioxidative effects. It is well known that one of the key elements in the development of diabetic complications is oxidative stress. The immune system is especially vulnerable to oxidative damage because many immune cells, such as neutrophils, produce reactive oxygen species and reactive nitrogen species as part of the body’s defense mechanisms to destroy invading pathogens. Reactive oxygen species/reactive nitrogen species are excessively produced by active peripheral neutrophils, and may damage essential cellular components, which in turn can cause vascular complications in diabetes. The present study was undertaken to evaluate the possible protective effects of annatto on the reactive oxygen species and nitric oxide (NO) inhibition in neutrophils from alloxan-induced diabetic rats. Adult female rats were divided into six groups based on receiving either a standard diet with or without supplementation of annatto extract or beta carotene. All animals were sacrificed 30 days after treatment and the neutrophils were isolated using two gradients of different densities. The reactive oxygen species and NO were quantified by a chemiluminescence and spectrophotometric assays, respectively. Our results show that neutrophils from diabetic animals produce significantly more reactive oxygen species and NO than their respective controls and that supplementation with beta carotene and annatto is able to modulate the production of these species. Annatto extract may have therapeutic potential for modulation of the balance reactive oxygen species/NO induced by diabetes. PMID:22573917

  20. Annato extract and β-carotene modulate the production of reactive oxygen species/nitric oxide in neutrophils from diabetic rats.

    Science.gov (United States)

    Rossoni-Júnior, Joamyr Victor; Araújo, Glaucy Rodrigues; Pádua, Bruno da Cruz; Chaves, Míriam Martins; Pedrosa, Maria Lúcia; Silva, Marcelo Eustáquio; Costa, Daniela Caldeira

    2012-05-01

    Annatto has been identified as carotenoids that have antioxidative effects. It is well known that one of the key elements in the development of diabetic complications is oxidative stress. The immune system is especially vulnerable to oxidative damage because many immune cells, such as neutrophils, produce reactive oxygen species and reactive nitrogen species as part of the body's defense mechanisms to destroy invading pathogens. Reactive oxygen species/reactive nitrogen species are excessively produced by active peripheral neutrophils, and may damage essential cellular components, which in turn can cause vascular complications in diabetes. The present study was undertaken to evaluate the possible protective effects of annatto on the reactive oxygen species and nitric oxide (NO) inhibition in neutrophils from alloxan-induced diabetic rats. Adult female rats were divided into six groups based on receiving either a standard diet with or without supplementation of annatto extract or beta carotene. All animals were sacrificed 30 days after treatment and the neutrophils were isolated using two gradients of different densities. The reactive oxygen species and NO were quantified by a chemiluminescence and spectrophotometric assays, respectively. Our results show that neutrophils from diabetic animals produce significantly more reactive oxygen species and NO than their respective controls and that supplementation with beta carotene and annatto is able to modulate the production of these species. Annatto extract may have therapeutic potential for modulation of the balance reactive oxygen species/NO induced by diabetes.

  1. Visible-light-assisted SLCs template synthesis of sea anemone-like Pd/PANI nanocomposites with high electrocatalytic activity for methane oxidation in acidic medium

    Science.gov (United States)

    Tan, De-Xin; Wang, Yan-Li

    2018-03-01

    Sea anemone-like palladium (Pd)/polyaniline (PANI) nanocomposites were synthesized via visible-light-assisted swollen liquid crystals (SLCs) template method. The resulting samples were characterized by transmission electron microscopy (TEM), selected area electron diffraction (SAED), energy dispersive spectrometer (EDS), x-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet-visible (UV–vis) absorption spectroscopy and Fourier transform infrared (FT-IR) spectroscopy, respectively. The electrocatalytic properties of Pd/PANI nanocomposites modified glass carbon electrode (GCE) for methane oxidation were investigated by cycle voltammetry (CV) and chronoamperometry. Those dispersed sea anemone-like Pd/PANI nanocomposites had an average diameter of 320 nm. The obtained Pd nanoparticles with an average diameter of about 45 nm were uniformly distributed in PANI matrix. Sea anemone-like Pd/PANI nanocomposites exhibited excellent electrocatalytic activity and stability for oxidation of methane (CH4).

  2. Nitric oxide alleviated arsenic toxicity by modulation of antioxidants and thiol metabolism in rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Amit Pal Singh

    2016-01-01

    Full Text Available Nitric oxide is a gaseous signalling molecule and has a profound impact on plant growth and development. It is reported to serve as pro oxidant as well as antioxidant in plant system. In present study, we evaluated the protective role of nitric oxide against AsV toxicity in rice plants. Arsenate exposure has hampered the plant growth, reduced the chlorophyll content and enhanced the oxidative stress while the exogenous NO supplementation has reverted these symptoms. Nitric oxide supplementation has reduced the As accumulation in root as well as shoot. Nitric oxide supplementation to AsV exposed plants has reduced the gene expression level of OsLsi1 and OsLsi2. Arsenate stress significantly impacted thiol metabolism, it reduced GSH content and GSH/GSSG ratio and enhanced the level of PCs. Nitric oxide supplementation maintained the GSH/GSSG ratio and reduced the level of PCs. Nitric oxide supplementation reverted AsV induced iron deficiency in shoot and had significant impact of gene expression level of various iron transporters (OsYSL2, OsFRDL1, OsIRT1 and OsIRO2. Conclusively, exogenous application of nitric oxide could be advantageous against AsV toxicity and could confer the tolerance to AsV stress in rice.

  3. Corrosion-deformation interactions in Inconel 718: application to stress corrosion in a supercritical aqueous medium and research of a material solution for the hydrothermal oxidation process

    International Nuclear Information System (INIS)

    Fournier, L.

    2000-01-01

    The aim of this study is to investigate the mechanisms responsible for stress corrosion cracking of nickel base superalloys in supercritical aerated water in order to determine a suitable material for the supercritical water oxidation (SCWO) reactors. For this purpose, alloy 718 is selected as a test material. We first focus on its 'hydrogen assisted cracking' behaviour at 25 deg C and on its 'oxidation assisted cracking behaviour' in the temperature range 400 deg C to 600 deg C. Then, its stress corrosion cracking behaviour in supercritical water is investigated for the first time by means of slow strain rate tensile tests (SSRT) performed on smooth specimens in de-ionised and aerated water at 400 deg C and 250 bars. Oxidation - deformation interactions are shown to control both the initiation and the propagation stages of alloy 718 stress corrosion cracks in supercritical water. We suggest that nickel base alloys without strengthening precipitates and with a high chromium content are suitable materials for the SCWO reactors. Such proposal is confirmed by SSRT performed on alloy 690 (28% Cr) specimens in de-ionised and aerated water at 400 deg C and 250 bars which do not reveal any susceptibility to stress corrosion cracking. (author)

  4. Medial prefrontal cortex N-methyl-D-aspartate receptor/nitric oxide/cyclic guanosine monophosphate pathway modulates both tachycardic and bradycardic baroreflex responses.

    Science.gov (United States)

    Ferreira-Junior, Nilson C; Fedoce, Alessandra G; Alves, Fernando H F; Resstel, Leonardo B M

    2013-10-01

    Neural reflex mechanisms, such as the baroreflex, are involved in regulating cardiovascular system activity. Previous results showed that the ventral portion of the medial prefrontal cortex (vMPFC) is involved in modulation only of the cardiac baroreflex bradycardic component. Moreover, vMPFC N-methyl-D-aspartate (NMDA) receptors modulate the bradycardia baroreflex, but the baroreflex tachycardic component has not been investigated. Furthermore, glutamatergic neurotransmission into the vMPFC is involved in activation of the cardiac sympathetic and parasympathetic nervous system. Finally, it has been demonstrated that glutamatergic neurotransmission into the vMPFC can be modulated by the endocannabinoid system and that activation of the CB1 cannabinoid receptor by anandamide, an endocannabinoid, can decrease both cardiac baroreflex bradycardic and tachycardic responses. Thus, there is the possibility that glutamatergic neurotransmission into the vMPFC does not modulate only the cardiac bradycardic component of the baroreflex. Therefore, the present study investigated whether glutamatergic neurotransmission into the vMPFC modulates both cardiac baroreflex bradycardic and tachycardic responses. We found that vMPFC bilateral microinjection of the NMDA receptor antagonist AP7 (4 nmol/200 nl), of a selective inhibitor of neuronal nitric oxide (NO) synthase N-propyl (0.08 nmol/200 nl), of the NO scavenger carboxy-PTIO (2 nmol/200 nl), or of the NO-sensitive guanylate cyclase ODQ (2 nmol/200 nl) decreased the baroreflex activity in unanesthetized rats. Therefore, our results demonstrate the participation of NMDA receptors, production of NO, and activation of guanylate cyclase in the vMPFC in the modulation of both cardiac baroreflex bradycardic and tachycardic responses. Copyright © 2013 Wiley Periodicals, Inc.

  5. Phycocyanobilin promotes PC12 cell survival and modulates immune and inflammatory genes and oxidative stress markers in acute cerebral hypoperfusion in rats

    Energy Technology Data Exchange (ETDEWEB)

    Marín-Prida, Javier [Centre for Research and Biological Evaluations (CEIEB), Institute of Pharmacy and Food, University of Havana, Ave. 23 e/ 214 y 222, La Lisa, PO Box: 430, Havana (Cuba); Pavón-Fuentes, Nancy [International Centre for Neurological Restoration (CIREN), Ave. 25 e/ 158 y 160, Playa, PO Box: 11300, Havana (Cuba); Llópiz-Arzuaga, Alexey; Fernández-Massó, Julio R. [Centre for Genetic Engineering and Biotechnology (CIGB), Ave. 31 e/158 y 190, Playa, PO Box: 6162, Havana (Cuba); Delgado-Roche, Liván [Centre for Research and Biological Evaluations (CEIEB), Institute of Pharmacy and Food, University of Havana, Ave. 23 e/ 214 y 222, La Lisa, PO Box: 430, Havana (Cuba); Mendoza-Marí, Yssel; Santana, Seydi Pedroso; Cruz-Ramírez, Alieski; Valenzuela-Silva, Carmen; Nazábal-Gálvez, Marcelo; Cintado-Benítez, Alberto [Centre for Genetic Engineering and Biotechnology (CIGB), Ave. 31 e/158 y 190, Playa, PO Box: 6162, Havana (Cuba); Pardo-Andreu, Gilberto L. [Centre for Research and Biological Evaluations (CEIEB), Institute of Pharmacy and Food, University of Havana, Ave. 23 e/ 214 y 222, La Lisa, PO Box: 430, Havana (Cuba); Polentarutti, Nadia [Istituto Clinico Humanitas (IRCCS), Rozzano (Italy); Riva, Federica [Department of Veterinary Science and Public Health (DIVET), University of Milano (Italy); Pentón-Arias, Eduardo [Centre for Genetic Engineering and Biotechnology (CIGB), Ave. 31 e/158 y 190, Playa, PO Box: 6162, Havana (Cuba); Pentón-Rol, Giselle [Centre for Genetic Engineering and Biotechnology (CIGB), Ave. 31 e/158 y 190, Playa, PO Box: 6162, Havana (Cuba)

    2013-10-01

    Since the inflammatory response and oxidative stress are involved in the stroke cascade, we evaluated here the effects of Phycocyanobilin (PCB, the C-Phycocyanin linked tetrapyrrole) on PC12 cell survival, the gene expression and the oxidative status of hypoperfused rat brain. After the permanent bilateral common carotid arteries occlusion (BCCAo), the animals were treated with saline or PCB, taking samples 24 h post-surgery. Global gene expression was analyzed with GeneChip Rat Gene ST 1.1 from Affymetrix; the expression of particular genes was assessed by the Fast SYBR Green RT-PCR Master Mix and Bioplex methods; and redox markers (MDA, PP, CAT, SOD) were evaluated spectrophotometrically. The PCB treatment prevented the H{sub 2}O{sub 2} and glutamate induced PC12 cell injury assessed by the MTT assay, and modulated 190 genes (93 up- and 97 down-regulated) associated to several immunological and inflammatory processes in BCCAo rats. Furthermore, PCB positively modulated 19 genes mostly related to a detrimental pro-inflammatory environment and counteracted the oxidative imbalance in the treated BCCAo animals. Our results support the view of an effective influence of PCB on major inflammatory mediators in acute cerebral hypoperfusion. These results suggest that PCB has a potential to be a treatment for ischemic stroke for which further studies are needed. - Highlights: • Phycocyanobilin (PCB) prevents H{sub 2}O{sub 2} and glutamate induced PC12 cell viability loss. • Anterior cortex and striatum are highly vulnerable to cerebral hypoperfusion (CH). • PCB modulates 190 genes associated to inflammation in acute CH. • PCB regulates 19 genes mostly related to a detrimental pro-inflammatory environment. • PCB restores redox and immune balances showing promise as potential stroke therapy.

  6. Competitive interactions between methane- and ammonia-oxidizing bacteria modulate carbon and nitrogen cycling in paddy soil

    NARCIS (Netherlands)

    Zheng, Yan; Huang, Rong; Wang, B.; Bodelier, P.L.E.; Jia, Z.

    2014-01-01

    Pure culture studies have demonstrated that methanotrophs and ammonia oxidizers can both carry out the oxidation of methane and ammonia. However, the expected interactions resulting from these similarities are poorly understood, especially in complex, natural environments. Using DNA-based stable

  7. Extreme mobility enhancement of two-dimensional electron gases at oxide interfaces by charge-transfer-induced modulation doping

    NARCIS (Netherlands)

    Chen, Yunzhong; Trier, F.; Wijnands, Tom; Green, R.J.; Gauquelin, N.; Egoavil, R.; Christensen, D.V.; Koster, Gertjan; Huijben, Mark; Bovet, N.; Macke, S.; He, F.; Sutarto, R.; Andersen, N.H.; Sulpizio, J.A.; Honig, M.; Prawiroatmodjo, G.E.D.K.; Jespersen, T.S.; Linderoth, S.; Ilani, S.; Verbeeck, J.; van Tendeloo, G.; Rijnders, Augustinus J.H.M.; Sawatzky, G.A.; Pryds, N.

    2015-01-01

    Two-dimensional electron gases (2DEGs) formed at the interface of insulating complex oxides promise the development of all-oxide electronic devices. These 2DEGs involve many-body interactions that give rise to a variety of physical phenomena such as superconductivity, magnetism, tunable

  8. Monitoring the aeration efficiency and carbon footprint of a medium-sized WWTP: experimental results on oxidation tank and aerobic digester.

    Science.gov (United States)

    Caivano, Marianna; Bellandi, Giacomo; Mancini, Ignazio M; Masi, Salvatore; Brienza, Rosanna; Panariello, Simona; Gori, Riccardo; Caniani, Donatella

    2017-03-01

    The efficiency of aeration systems should be monitored to guarantee suitable biological processes. Among the available tools for evaluating the aeration efficiency, the off-gas method is one of the most useful. Increasing interest towards reducing greenhouse gas (GHG) emissions from biological processes has resulted in researchers using this method to quantify N 2 O and CO 2 concentrations in the off-gas. Experimental measurements of direct GHG emissions from aerobic digesters (AeDs) are not available in literature yet. In this study, the floating hood technique was used for the first time to monitor AeDs. The floating hood technique was used to evaluate oxygen transfer rates in an activated sludge (AS) tank of a medium-sized municipal wastewater treatment plant located in Italy. Very low values of oxygen transfer efficiency were found, confirming that small-to-medium-sized plants are often scarcely monitored and wrongly managed. Average CO 2 and N 2 O emissions from the AS tank were 0.14 kg CO2 /kg bCOD and 0.007 kg CO2,eq /kg bCOD , respectively. For an AeD, 3 × 10 -10  kg CO2 /kg bCOD direct CO 2 emissions were measured, while CO 2,eq emissions from N 2 O were 4 × 10 -9  kg CO2,eq /kg bCOD . The results for the AS tank and the AeD were used to estimate the net carbon and energy footprint of the entire plant.

  9. Docosahexaenoic (DHA modulates phospholipid-hydroperoxide glutathione peroxidase (Gpx4 gene expression to ensure self-protection from oxidative damage in hippocampal cells

    Directory of Open Access Journals (Sweden)

    Veronica eCasañas-Sanchez

    2015-07-01

    Full Text Available Docosahexaenoic acid (DHA, 22:6n-3 is a unique polyunsaturated fatty acid particularly abundant in nerve cell membrane phospholipids. DHA is a pleiotropic molecule that, not only modulates the physicochemical properties and architecture of neuronal plasma membrane, but it is also involved in multiple facets of neuronal biology, from regulation of synaptic function to neuroprotection and modulation of gene expression. As a highly unsaturated fatty acid due to the presence of six double bonds, DHA is susceptible for oxidation, especially in the highly pro-oxidant environment of brain parenchyma. We have recently reported the ability of DHA to regulate the transcriptional program controlling neuronal antioxidant defenses in a hippocampal cell line, especially the glutathione/glutaredoxin system. Within this antioxidant system, DHA was particularly efficient in triggering the upregulation of Gpx4 gene, which encodes for the nuclear, cytosolic and mitochondrial isoforms of phospholipid-hydroperoxide glutathione peroxidase (PH-GPx/GPx4, the main enzyme protecting cell membranes against lipid peroxidation and capable to reduce oxidized phospholipids in situ. We show here that this novel property of DHA is also significant in the hippocampus of wild-type mice and APP/PS1 transgenic mice, a familial model of Alzheimer’s disease. By doing this, DHA stimulates a mechanism to self-protect from oxidative damage even in the neuronal scenario of high aerobic metabolism and in the presence of elevated levels of transition metals, which inevitably favor the generation of reactive oxygen species. Noticeably, DHA also upregulated a novel Gpx4 splicing variant, harboring part of the first intronic region, which according to the ‘sentinel RNA hypothesis’ would expand the ability of Gpx4 (and DHA to provide neuronal antioxidant defense independently of conventional nuclear splicing in cellular compartments, like dendritic zones, located away from nuclear

  10. Modulation of innate immune responses and induction of oxidative stress biomarkers in Pangasianodon hypophthalmus following an experimental infection with dactylogyrid monogeneans.

    Science.gov (United States)

    Kumar, Saurav; Raman, R P; Prasad, K Pani; Srivastava, P P; Kumar, Sanath; Rajendran, K V

    2017-04-01

    Modulation of innate immune activity and oxidative stress response of Pangasianodon hypophthalmus through experimental infection with (Thaparocleidus sp.) dactylogyrid monogenean was studied. A standard cohabitation method was used to infect healthy experimental fish. After 14 days, dactylogyrid (gill monogenean) infested fish were sampled and categorised into three different infected groups namely (T1) low (50 mean dactylogyrid per gill arch per fish) along with a control group T0 (un-infested fish). Serum and tissues (gills and liver) were collected from experimental fish and analyzed for markers of innate immune and oxidative stress, respectively. The results showed that respiratory burst activity, myeloperoxidase level, serum lysozyme, α-2 macroglobulin and total serum immunoglobulin level were significantly (p immunoglobulins, but also the oxidative stress biomarkers. The baseline data obtained in the present study will be valuable in understanding the host-parasite relationship and the dynamics of innate, oxidative stress responses and susceptibility of P. hypophthalmus to different degrees of parasitosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Sesamin Modulates Tyrosine Hydroxylase, Superoxide Dismutase, Catalase, Inducible No Synthase and Interleukin-6 Expression in Dopaminergic Cells Under Mpp+-Induced Oxidative Stress

    Directory of Open Access Journals (Sweden)

    Vicky Lahaie-Collins

    2008-01-01

    Full Text Available Oxidative stress is regarded as a mediator of nerve cell death in several neurodegenerative disorders, such as Parkinson's disease. Sesamin, a lignan mainly found in sesame oil, is currently under study for its anti-oxidative and possible neuroprotective properties. We used 1-methyl-4-phenyl-pyridine (MPP+ ion, the active metabolite of the potent parkinsonism-causing toxin 1-methyl-4-phenyl-1,2,5,6-tetrahydropyridine, to produce oxidative stress and neurodegeneration in neuronal PC12 cells, which express dopamine, as well as neurofilaments. Our results show that picomolar doses of sesamin protected neuronal PC12 cells from MPP+-induced cellular death, as revealed by colorimetric measurements and production of reactive oxygen species. We also demonstrated that sesamin acted by rescuing tyrosine hydroxylase levels from MPP+-induced depletion. Sesamin, however, did not modulate dopamine transporter levels, and estrogen receptor-alpha and -beta protein expression. By examining several parameters of cell distress, we found that sesamin also elicited a strong increase in superoxide dismutase activity as well as protein expression and decreased catalase activity and the MPP+ stimulated inducible nitric oxide synthase protein expression, in neuronal PC12 cells. Finally, sesamin possessed significant anti-inflammatory properties, as disclosed by its potential to reduce MPP+-induced interleukin-6 mRNA levels in microglia. From these studies, we determined the importance of the lignan sesamin as a neuroprotective molecule and its possible role in complementary and/or preventive therapies of neurodegenerative diseases.

  12. Electrochemical oxidation of ethanol using PtRh/C electrocatalysts in alkaline medium and synthesized by sodium borohydride and alcohol reduction

    International Nuclear Information System (INIS)

    Fontes, Eric Hossein

    2017-01-01

    PtRh/C were prepared by the following atomic proportions: (100,0), (0,100), (90,10), (70,30) and (50,50). The methods employed in the synthesis of these materials were reduction by sodium borohydride and reduction by alcohol. The metal salts used were H 2 PtCl 6 3•6H 2 0 and (RhNO 3 ) 3 , the support used was Carbon black XC72 and the bulk metal composition was 20% and 80% of support. The electrocatalysts were characterized by Energy Dispersive X-ray spectroscopy, X-ray diffraction and Transmission electron microscopy. The ethanol electrochemical oxidation mechanism was investigated by in situ Fourier Transform Infrared Spectroscopy couple to an Attenuated Total Reflection technique. The electrocatalytic activity were evaluated by Cyclic Voltammetry, Linear Sweep Voltammetry and Chronoamperometry techniques. The Fuel Cells tests were made in a single direct alcohol fuel cell with alkaline membrane. The working electrodes were prepared by a thin porous coating technique. X-ray diffraction allowed to verify metallic alloys, segregate phases and to calculate the percentage of metallic alloys. It was else possible to identify crystallographic phases. Infrared Spectroscopy allowed to verify that the electrochemical oxidation of ethanol was carried out by an incomplete mechanism. PtRh(70:30)/C prepared by sodium borohydride produced large amounts of carbon dioxide and acetaldehyde. Rh/C showed electrocatalytic activity when compared with other materials studied.

  13. The Development of a New Inhibition Kinetic Spectrophotometric Method for the Determination of Phenylhydrazine Based on its Inhibitory Effect on Oxidation of Methyl Red by Bromate in Micellar Medium

    Directory of Open Access Journals (Sweden)

    Mohsen Keyvanfard

    2010-01-01

    Full Text Available A new, simple, sensitive and selective kinetic spectrophotometric method was developed for the determination of trace amounts of phenylhydrazine over the range of 0.02-0.30 μg/mL. The method is based on the inhibitory effect of phenylhydrazine on the oxidation of methyl red by bromate in acidic and micellar medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of methyl red at 518 nm with a fixed-time 0.5–2.0 min from initiation of the reaction..The relative standard deviation of 0.08 and 0.2 μg/mL phenylhydrazine was 1.7 and 2.4%, respectively. The method was applied to the determination of phenylhydrazine in water samples.

  14. Effects of Physical Activity and Ginkgo Biloba on Cognitive Function and Oxidative Stress Modulation in Ischemic Rats.

    Science.gov (United States)

    Vaghef, Ladan; Bafandeh Gharamaleki, Hassan

    2017-09-01

    Either exercise or Ginkgo biloba is reported to improve cognitive functioning. The aim of this study is to compare the protective effects of forced exercise and Ginkgo biloba on oxidative stress as well as memory impairments induced by transient cerebral ischemia. Adult male Wistar rats were treated with treadmill running or Ginkgo biloba extract for 2 weeks before cerebral ischemia. Memory was assessed using a Morris water maze (MWM) task. At the end of the behavioral testing, oxidative stress biomarkers were evaluated in the hippocampus tissue. As expected, the cerebral ischemia induced memory impairment in the MWM task, and oxidative stress in the hippocampus. These effects were significantly prevented by treadmill running. Indeed, it ameliorated oxidative stress and memory deficits induced by ischemia. In contrast, Ginkgo biloba was not as effective as exercise in preventing ischemia-induced memory impairments. The results confirmed the neuroprotective effects of treadmill running on hippocampus-dependent memory.

  15. Change in the Enthalpy of Magnetite Concentrates from the Sokolovsk-Sarbaisk Mining-Concentration Combine during Heating in an Oxidizing Medium,

    Science.gov (United States)

    The changes in enthalpy and average specific heat during heating of the concentration containing SiO2 3.08, Al2O3 0.55, FeO 28.9, Fe2O3 64.94, CaO ...0.86, MgO 0.61, TiO2 0.16, MnO 0.145, P2O5 0.018, Cr2O3 0.004, V2O5 0.16, S(total) 0.38, and loss on ignition 0.8%, were determined at 100-200C under conditions corresponding to oxidizing roasting. (Author)

  16. Effect of ozone on ruthenium species in alkaline medium. Pt. II. Oxidation of pentahydroxo nitrosyl ruthenate(II) ion RuNO(OH)52-

    International Nuclear Information System (INIS)

    Floquet, S.; Eysseric, C.

    2006-01-01

    Oxidation of the nitrosyl ruthenium complex RuNO(OH) 5 2- has been carried out in sodium hydroxide solutions in contact with a gas flow containing ozone. The RuNO(OH) 5 2- complex is converted successively into ruthenate and perruthenate ions. An empirical kinetic rate law for the first step has been determined and was shown to depend on concentrations of (i) the ruthenium complex, (ii) the hydroxide ions and (iii) ozone concentration in the gas flow. The second step of the reaction, corresponding to the perruthenate ion formation, shows a complex mechanism and four competing reactions have been proposed to represent it. The influences on the second step kinetics of several parameters such as ozone or hydroxide concentrations or the conditions of the gas-liquid exchange area are also qualitatively discussed. (orig.)

  17. Effect of ozone on ruthenium species in alkaline medium. Pt. II. Oxidation of pentahydroxo nitrosyl ruthenate(II) ion RuNO(OH){sub 5}{sup 2-}

    Energy Technology Data Exchange (ETDEWEB)

    Floquet, S. [Commissariat a l' Energie Atomique (CEA/Valrho), Bagnols-sur-Ceze (France); Inst. Lavoisier, IREM UMR 8637, Univ. de Versailles Saint-Quentin, Versailles (France); Eysseric, C. [Commissariat a l' Energie Atomique (CEA/Valrho), Bagnols-sur-Ceze (France)

    2006-07-01

    Oxidation of the nitrosyl ruthenium complex RuNO(OH){sub 5}{sup 2-} has been carried out in sodium hydroxide solutions in contact with a gas flow containing ozone. The RuNO(OH){sub 5}{sup 2-} complex is converted successively into ruthenate and perruthenate ions. An empirical kinetic rate law for the first step has been determined and was shown to depend on concentrations of (i) the ruthenium complex, (ii) the hydroxide ions and (iii) ozone concentration in the gas flow. The second step of the reaction, corresponding to the perruthenate ion formation, shows a complex mechanism and four competing reactions have been proposed to represent it. The influences on the second step kinetics of several parameters such as ozone or hydroxide concentrations or the conditions of the gas-liquid exchange area are also qualitatively discussed. (orig.)

  18. Induction of apoptosis by the medium-chain length fatty acid lauric acid in colon cancer cells due to induction of oxidative stress.

    Science.gov (United States)

    Fauser, J K; Matthews, G M; Cummins, A G; Howarth, G S

    2013-01-01

    Fatty acids are classified as short-chain (SCFA), medium-chain (MCFA) or long-chain and hold promise as adjunctive chemotherapeutic agents for the treatment of colorectal cancer. The antineoplastic potential of MCFA remains underexplored; accordingly, we compared the MCFA lauric acid (C12:0) to the SCFA butyrate (C4:0) in terms of their capacity to induce apoptosis, modify glutathione (GSH) levels, generate reactive oxygen species (ROS), and modify phases of the cell cycle in Caco-2 and IEC-6 intestinal cell lines. Caco-2 and IEC-6 cells were treated with lauric acid, butyrate, or vehicle controls. Apoptosis, ROS, and cell cycle analysis were determined by flow cytometry. GSH availability was assessed by enzymology. Lauric acid induced apoptosis in Caco-2 (p lauric acid reduced GSH availability and generated ROS compared to butyrate (p Lauric acid reduced Caco-2 and IEC-6 cells in G0/G1and arrested cells in the S and G2/M phases. Lauric acid induced apoptosis in IEC-6 cells compared to butyrate (p lauric acid induced high levels of ROS compared to butyrate. Compared to butyrate, lauric acid displayed preferential antineoplastic properties, including induction of apoptosis in a CRC cell line.

  19. Regulator of G protein signaling-1 modulates paraquat-induced oxidative stress and longevity via the insulin like signaling pathway in Caenorhabditis elegans.

    Science.gov (United States)

    Wu, Mingyu; Kang, Xin; Wang, Qiang; Zhou, Chunyu; Mohan, Chandra; Peng, Ai

    2017-05-05

    Insulin or insulin like signaling (IIS) pathway is a crucial pathway in Caenorhabditis elegans associated with mediating longevity, and stress resistance. Regulators of G protein signaling (RGS) also modulate stress resistance and longevity in multiple in vitro and in vivo models. However, the mechanism underlying RGS mediating stress resistance and longevity remains largely unclear. Here we report that rgs-1, an important member of rgs family, is a novel modulator of IIS pathway in C. elegans. We found that the loss of rgs-1 dramatically promoted paraquat resistance in C. elegans. Further genetic analyses demonstrated that rgs-1 acted downstream of daf-2 and upstream of age-1, pdk-1, daf-16. Instead of affecting those IIS-associated genes in transcriptional process, loss of rgs-1 promoted DAF-16's nucleus translocation and subset genes' expression in paraquat-induced oxidative status. By this way, rgs-1 mutant worms exhibited lower ROS damage and longer survival time than wild type worms when both exposed to paraquat. Other than paraquat exposure, rgs-1 mutant also promoted lifespan and cadmium resistance relying on daf-16. As rgs is evolutionarily conserved, our findings open a new insight into rgs family and its role in paraquat-induced oxidative stress and longevity in C. elegans or even mammals. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Synthesis of Minerals with Iron Oxide and Hydroxide Contents as a Sorption Medium to Remove Arsenic from Water for Human Consumption

    Science.gov (United States)

    Garrido-Hoyos, Sofia; Romero-Velazquez, Lourdes

    2015-01-01

    Arsenic has been classified as a toxic and carcinogenic chemical element. It therefore presents a serious environmental problem in different regions of the country and the world. In the present work, two adsorbent media were developed and evaluated to remove arsenic from water in the Pájaro Verde mine shaft, Huautla, Tlaquiltenango, Morelos. The media were synthesized and characterized, obtaining a surface area of 43.04 m2·g−1 for the goethite and 2.44 m2·g−1 for silica sand coated with Fe(III). To conduct the sorption kinetics and isotherms, a 23 factorial design was performed for each medium in order to obtain the optimal conditions for the factors of arsenic concentration, pH and mass of the adsorbent. The best results were obtained for goethite, with a removal efficiency of 98.61% (C0 of As(V) 0.360 mg·L−1), and an effluent concentration of 0.005 mg·L−1, a value that complies with the modified Official Mexican Standard NOM-127-SSA1-1994 [1] and WHO guidelines (2004) [2]. The kinetic equation that best fit the experimental data was the pseudo-second-order, resulting in the highest values for the constants for synthetic goethite, with a rate constant sorption of 4.019·g·mg−1·min−1. With respect to the sorption isotherms, both media were fitted to the Langmuir-II linear model with a sorption capacity (qm) of 0.4822 mg·g−1 for goethite and 0.2494 mg·g−1 for silica sand coated with Fe(III). PMID:26703707

  1. Galectin-1 Reduces Neuroinflammation via Modulation of Nitric Oxide-Arginase Signaling in HIV-1 Transfected Microglia: a Gold Nanoparticle-Galectin-1 "Nanoplex" a Possible Neurotherapeutic?

    Science.gov (United States)

    Aalinkeel, Ravikumar; Mangum, Courtney S; Abou-Jaoude, Eliane; Reynolds, Jessica L; Liu, Maixian; Sundquist, Karin; Parikh, Neil U; Chaves, Lee D; Mammen, Manoj J; Schwartz, Stanley A; Mahajan, Supriya D

    2017-03-01

    Galectins are a family of β-galactoside-binding lectins that are important modulators of homeostasis in the central nervous system (CNS). Galectin-1 is a pivotal regulator of microglia activation that alters the immune balance from neurodegeneration to neuroprotection and could have therapeutic relevance in HIV associated neurocognitive disorders (HAND). We have previously shown that galectin-1 treatment decreased oxidative stress in microglia and hypothesize that the mechanism underlying this phenomenon is the cross regulatory interactions between Nitric oxide (NO) and Arginase I activity in microglia. We induced microglial activation and examined the effect of galectin-1 on the expression of various M1/M2 microglial phenotypic markers. Since, TNF-α is associated with activation of microglial cells involved in pathogenesis of neurodegenerative diseases, we treated HIV transfected human microglial cell cultures (CHME-5/HIV) with TNF-α followed by treatment with galectin-1, to examine the galectin-1 mediated neuro-modulatory response. Our results show that treatment of CHME-5/HIV microglia with galectin-1 reduced TNF-α induced oxidative stress by ~40%, and also significantly reduced iNOS gene expression and NO production while correspondingly increasing arginase-1, cationic amino acid transporter (CAT-1) gene expression and arginase activity. Galectin-1 treatment results in shifting microglia polarization from M1 toward the beneficial M2 phenotype which may prevent neurodegeneration and promote neuroprotection. Thus, our data suggests that galectin-1 treatment reduces neuroinflammation in the CNS microenvironment via the modulation of the NO-arginase network in microglia and thus could play a neuroprotective role in HAND. Further, the therapeutic potential of galectin-1 could be enhanced by conjugation of galectin-1 onto gold nanoparticles (Au-NP), resulting in a nanogold-galectin-1 (Au-Gal-1) multivalent complex that will have more clinical translational

  2. Uncaria tomentosa exerts extensive anti-neoplastic effects against the Walker-256 tumour by modulating oxidative stress and not by alkaloid activity.

    Directory of Open Access Journals (Sweden)

    Arturo Alejandro Dreifuss

    Full Text Available This study aimed to compare the anti-neoplastic effects of an Uncaria tomentosa (UT brute hydroethanolic (BHE extract with those of two fractions derived from it. These fractions are choroformic (CHCl3 and n-butanolic (BuOH, rich in pentacyclic oxindole alkaloids (POA and antioxidant substances, respectively. The cancer model was the subcutaneous inoculation of Walker-256 tumour cells in the pelvic limb of male Wistar rat. Subsequently to the inoculation, gavage with BHE extract (50 mg.kg(-1 or its fractions (as per the yield of the fractioning process or vehicle (Control was performed during 14 days. Baseline values, corresponding to individuals without tumour or treatment with UT, were also included. After treatment, tumour volume and mass, plasma biochemistry, oxidative stress in liver and tumour, TNF-α level in liver and tumour homogenates, and survival rates were analysed. Both the BHE extract and its BuOH fraction successfully reduced tumour weight and volume, and modulated anti-oxidant systems. The hepatic TNF-α level indicated a greater effect from the BHE extract as compared to its BuOH fraction. Importantly, both the BHE extract and its BuOH fraction increased the survival time of the tumour-bearing animals. Inversely, the CHCl3 fraction was ineffective. These data represent an in vivo demonstration of the importance of the modulation of oxidative stress as part of the anti-neoplastic activity of UT, as well as constitute evidence of the lack of activity of isolated POAs in the primary tumour of this tumour lineage. These effects are possibly resulting from a synergic combination of substances, most of them with antioxidant properties.

  3. Uncaria tomentosa exerts extensive anti-neoplastic effects against the Walker-256 tumour by modulating oxidative stress and not by alkaloid activity.

    Science.gov (United States)

    Dreifuss, Arturo Alejandro; Bastos-Pereira, Amanda Leite; Fabossi, Isabella Aviles; Lívero, Francislaine Aparecida Dos Reis; Stolf, Aline Maria; Alves de Souza, Carlos Eduardo; Gomes, Liana de Oliveira; Constantin, Rodrigo Polimeni; Furman, Aline Emmer Ferreira; Strapasson, Regiane Lauriano Batista; Teixeira, Simone; Zampronio, Aleksander Roberto; Muscará, Marcelo Nicolás; Stefanello, Maria Elida Alves; Acco, Alexandra

    2013-01-01

    This study aimed to compare the anti-neoplastic effects of an Uncaria tomentosa (UT) brute hydroethanolic (BHE) extract with those of two fractions derived from it. These fractions are choroformic (CHCl3) and n-butanolic (BuOH), rich in pentacyclic oxindole alkaloids (POA) and antioxidant substances, respectively. The cancer model was the subcutaneous inoculation of Walker-256 tumour cells in the pelvic limb of male Wistar rat. Subsequently to the inoculation, gavage with BHE extract (50 mg.kg(-1)) or its fractions (as per the yield of the fractioning process) or vehicle (Control) was performed during 14 days. Baseline values, corresponding to individuals without tumour or treatment with UT, were also included. After treatment, tumour volume and mass, plasma biochemistry, oxidative stress in liver and tumour, TNF-α level in liver and tumour homogenates, and survival rates were analysed. Both the BHE extract and its BuOH fraction successfully reduced tumour weight and volume, and modulated anti-oxidant systems. The hepatic TNF-α level indicated a greater effect from the BHE extract as compared to its BuOH fraction. Importantly, both the BHE extract and its BuOH fraction increased the survival time of the tumour-bearing animals. Inversely, the CHCl3 fraction was ineffective. These data represent an in vivo demonstration of the importance of the modulation of oxidative stress as part of the anti-neoplastic activity of UT, as well as constitute evidence of the lack of activity of isolated POAs in the primary tumour of this tumour lineage. These effects are possibly resulting from a synergic combination of substances, most of them with antioxidant properties.

  4. Rutin reverses radiation-induced oxidative DNA damage and inflammation through the modulation of p38/Nf-Kb and Keap1/Nrf2 pathway

    International Nuclear Information System (INIS)

    Manna, Krishnendu; Khan, Amitava; Biswas, Sushobhan; Das, Ujjal; Sengupta, Aaveri; Dey, Sanjit; Chakraborty, Anindita

    2016-01-01

    Rutin (RU), widely known plant polyphenol, possesses wide range of biological activities. In this study, we evaluated the effect of RU on radiation (IR)-induced oxidative stress and inflammation in murine liver and explored the potential mechanisms underlying this effect. Swiss albino mice were subjected to oral pretreatment of RU (75 mg/kg body weight) for three consecutive days before irradiation (6 Gy). Plethora of biochemical indices were carried out to determine the hepato protective effect of RU. Molecular mechanism of action was also assessed through employing the immunoblot, flow cytometry and immunofluorescence techniques. Hepatoprotective effects of RU were associated with the upregulation of antioxidant enzyme activities (SOD, catalase and GSH) and down regulation of serum toxicity markers (ALT, AST and LDH). Results also demonstrated that RU significantly down regulated the levels of hepatic inflammatory markers like TNF-α, IL-6 and expressions of p38-MAPK, NF-κB, iNOS and COX-2. Histopathological changes further confirmed the biochemical and immunohistochemical results showing that IR caused significant structural damage to liver which were reversed by pretreatment of RU. RU also significantly suppressed the IR-induced activation of Keap1 and modulated the phosphorylation of PI3K/AKT. Further, pretreatment with RU augmented the expression of Nrf2 thereby enhancing the activity of downstream phase-2 detoxifying hepatic enzymes (HO-1, NQO-1, GST and Mn-SOD) which altered the IR-induced oxidative imbalance. The present results is evidence based mechanism that RU remained a promising radioprotector in attenuating IR-induced oxidative stress, inflammation and hepatotoxicity through the modulation of Nrf2/HO-1 and p38 /NF-κB signaling pathway. (author)

  5. Intake of Red Wine in Different Meals Modulates Oxidized LDL Level, Oxidative and Inflammatory Gene Expression in Healthy People: A Randomized Crossover Trial

    Directory of Open Access Journals (Sweden)

    Laura Di Renzo

    2014-01-01

    Full Text Available Several studies have found that adherence to the Mediterranean Diet, including consumption of red wine, is associated with beneficial effects on oxidative and inflammatory conditions. We evaluate the outcome of consumption of a McDonald’s Meal (McD and a Mediterranean Meal (MM, with and without the additive effect of red wine, in order to ascertain whether the addition of the latter has a positive impact on oxidized (ox- LDL and on expression of oxidative and inflammatory genes. A total of 24 subjects were analyzed for ox-LDL, CAT, GPX1, SOD2, SIRT2, and CCL5 gene expression levels, before and after consumption of the 4 different meal combinations with washout intervals between each meal. When red wine is associated with McD or MM, values of ox-LDL are lowered (P<0.05 and expression of antioxidant genes is increased, while CCL5 expression is decreased (P<0.05. SIRT2 expression after MM and fasting with red wine is significantly correlated with downregulation of CCL5 and upregulation of CAT (P<0.001. GPX1 increased significantly in the comparison between baseline and all conditions with red wine. We highlighted for the first time the positive effect of red wine intake combined with different but widely consumed meal types on ox-LDL and gene expression. Trial Registration. This trial is registered with ClinicalTrials.gov NCT01890070.

  6. Quercetin modulates iNOS, eNOS and NOSTRIN expressions and attenuates oxidative stress in warm hepatic ischemia-reperfusion injury in rats

    Directory of Open Access Journals (Sweden)

    Mohamed Abd-Elbaset

    2015-09-01

    Full Text Available The pathogenesis of hepatic ischemia/reperfusion (I/R is mediated through the generation of oxidative and nitrosative stress-induced cell injury. Hence, the present study was designed to evaluate the hepatoprotective effect of quercetin (QR compared to N-acetylcysteine (NAC against hepatic I/R injury in rats and to assess iNOS, eNOS and NOSTRIN protein expressions, as a possible mechanism of its hepatoprotective effect. Hepatic ischemia was surgically performed by occlusion of hepatic pedicle (hepatic artery, portal vein, bile duct that supplies the left and medial lobes (approximately 70% of the total liver mass, for 30 min with a vascular clamp followed by releasing the clamp and the liver was reperfused for 30 min. QR-pretreatment increased eNOS protein expression with simultaneous decrease in iNOS and NOSTRIN protein expressions. It also decreased serum aspartate aminotransferase (AST, alanine aminotransferases (ALT and hepatic myeloperoxidase (MPO activities. In addition, it restored the depleted content of reduced glutathione (GSH and decreased malondialdehyde (MDA and nitric oxide (NO levels. A notable finding is that QR alleviated I/R-induced histopathological changes. Therefore, the present study illustrates the hepatoprotective effect of quercetin compared to N-acetylcysteine against ischemia/reperfusion-induced liver injury by inhibiting oxidative stress and by modulating iNOS, eNOS and NOSTRIN protein expressions.

  7. Antitumorigenic potential of linalool is accompanied by modulation of oxidative stress: an in vivo study in sarcoma-180 solid tumor model.

    Science.gov (United States)

    Jana, Samarjit; Patra, Kartick; Sarkar, Shehnaz; Jana, Jagannath; Mukherjee, Gopeswar; Bhattacharjee, Shamee; Mandal, Deba Prasad

    2014-01-01

    Coriander, used as a common food seasoning, contains linalool as the main constituent of its essential oil. In this study, we tested the effect of linalool vis-à-vis that of a conventional chemotherapeutic drug, cyclophosphamide, against solid S-180 tumor-bearing Swiss albino mice. Tumor volume, cell count, cell cycle phase distribution, apoptosis, and proliferation markers indicate that linalool has potent antitumor activity. In vitro and in vivo data suggest that induction of oxidative stress might be responsible for the anticancer effect of linalool. However, interestingly, unlike cyclophosphamide, linalool did not induce myelosuppression or hepatotoxicity in mice as evident from bone marrow cell count, status of hepatic oxidative stress/antioxidant enzymes, and histopathology. Thus, linalool exerted prooxidant effect in tumor tissue and an antioxidant effect in liver. This is also supported by the expression of Nrf-2 and p21, which are considered to be important players in response to oxidative stress. Moreover, administration of linalool modulated the proliferation of spleen cells in tumor-bearing mice challenged with lipopolysaccharide. Finally, the detection of linalool in sera and tumor tissues by HPLC confirmed its bioavailability. In conclusion, linalool showed differential cytotoxicity towards tumor and normal cells in contrast to cyclophosphamide, which is uniformly toxic to both.

  8. AsrR is an oxidative stress sensing regulator modulating Enterococcus faecium opportunistic traits, antimicrobial resistance, and pathogenicity.

    Directory of Open Access Journals (Sweden)

    François Lebreton

    Full Text Available Oxidative stress serves as an important host/environmental signal that triggers a wide range of responses in microorganisms. Here, we identified an oxidative stress sensor and response regulator in the important multidrug-resistant nosocomial pathogen Enterococcus faecium belonging to the MarR family and called AsrR (antibiotic and stress response regulator. The AsrR regulator used cysteine oxidation to sense the hydrogen peroxide which results in its dissociation to promoter DNA. Transcriptome analysis showed that the AsrR regulon was composed of 181 genes, including representing functionally diverse groups involved in pathogenesis, antibiotic and antimicrobial peptide resistance, oxidative stress, and adaptive responses. Consistent with the upregulated expression of the pbp5 gene, encoding a low-affinity penicillin-binding protein, the asrR null mutant was found to be more resistant to β-lactam antibiotics. Deletion of asrR markedly decreased the bactericidal activity of ampicillin and vancomycin, which are both commonly used to treat infections due to enterococci, and also led to over-expression of two major adhesins, acm and ecbA, which resulted in enhanced in vitro adhesion to human intestinal cells. Additional pathogenic traits were also reinforced in the asrR null mutant including greater capacity than the parental strain to form biofilm in vitro and greater persistance in Galleria mellonella colonization and mouse systemic infection models. Despite overexpression of oxidative stress-response genes, deletion of asrR was associated with a decreased oxidative stress resistance in vitro, which correlated with a reduced resistance to phagocytic killing by murine macrophages. Interestingly, both strains showed similar amounts of intracellular reactive oxygen species. Finally, we observed a mutator phenotype and enhanced DNA transfer frequencies in the asrR deleted strain. These data indicate that AsrR plays a major role in antimicrobial

  9. Oligomeric proanthocyanidins (OPCs) modulating radiation-induced oxidative stress on functional and structural performance of eye in male rats

    International Nuclear Information System (INIS)

    Said, U.Z.; Soliman, S.M.; Azab, Kh.Sh.; El-Tahawy, N.A.

    2005-01-01

    Eye oxidative stress may play a major role in the etiology and pathogenesis of eye disorders such as macular degeneration and photic injury of retinal degeneration that lead to vision loss. Proanthocyanidins derived from pine bark and from grape seeds have various anti pathophysiological functions. This study was performed to evaluate the role of oligomeric proanthocyanidins (OPCs) on the radiation-induced changes in rat eye tissues. OPCs were supplemented to rats (100 mg /kg body weight/ day) for 14 successive days before and 7 successive days after exposure to 7 Gy (single dose) of whole body gamma irradiation. The results revealed radiation-induced depletion in the activities of eye endogenous antioxidant enzymes and rise in pro-oxidant levels. Supplementation of OPCs pre- and post-irradiation has significantly reduced the levels of thiobarbituric acid reactive substances, xanthine oxidase, and significantly ameliorated the activities of xanthine dehydrogenase and reactive oxygen scavenging enzymes such as superoxide dismutase, glutathione peroxidase and catalase activities in eye tissues. OPCs significantly ameliorated the radiation-induced changes in levels of insulin and glucose in the serum. The oxidative stress induced cellular damage as indicated by retardation in the responses of eye to photo stimulation as well as histopathological changes in the eye tissues. Severe intra-retinal hemorrhages, cornea swelling, disruption of photoreceptor layer of the retina and epithelial necrosis were seen. The eye tissues of rats that received OPCs supplement showed significant less severe histological damage and remarkable improvement in photo stimulation responses when compared to irradiated rats on the 7 T h and 21 s t days after exposure to gamma irradiation. According to the results obtained, it could be concluded that OPCs might protect the eye tissues from the oxidative stress possibly by virtue of its anti oxidative activity through augmentation of antioxidant

  10. AsrR Is an Oxidative Stress Sensing Regulator Modulating Enterococcus faecium Opportunistic Traits, Antimicrobial Resistance, and Pathogenicity

    Science.gov (United States)

    Lebreton, François; van Schaik, Willem; Sanguinetti, Maurizio; Posteraro, Brunella; Torelli, Riccardo; Le Bras, Florian; Verneuil, Nicolas; Zhang, Xinglin; Giard, Jean-Christophe; Dhalluin, Anne; Willems, Rob J. L.; Leclercq, Roland; Cattoir, Vincent

    2012-01-01

    Oxidative stress serves as an important host/environmental signal that triggers a wide range of responses in microorganisms. Here, we identified an oxidative stress sensor and response regulator in the important multidrug-resistant nosocomial pathogen Enterococcus faecium belonging to the MarR family and called AsrR (antibiotic and stress response regulator). The AsrR regulator used cysteine oxidation to sense the hydrogen peroxide which results in its dissociation to promoter DNA. Transcriptome analysis showed that the AsrR regulon was composed of 181 genes, including representing functionally diverse groups involved in pathogenesis, antibiotic and antimicrobial peptide resistance, oxidative stress, and adaptive responses. Consistent with the upregulated expression of the pbp5 gene, encoding a low-affinity penicillin-binding protein, the asrR null mutant was found to be more resistant to β-lactam antibiotics. Deletion of asrR markedly decreased the bactericidal activity of ampicillin and vancomycin, which are both commonly used to treat infections due to enterococci, and also led to over-expression of two major adhesins, acm and ecbA, which resulted in enhanced in vitro adhesion to human intestinal cells. Additional pathogenic traits were also reinforced in the asrR null mutant including greater capacity than the parental strain to form biofilm in vitro and greater persistance in Galleria mellonella colonization and mouse systemic infection models. Despite overexpression of oxidative stress-response genes, deletion of asrR was associated with a decreased oxidative stress resistance in vitro, which correlated with a reduced resistance to phagocytic killing by murine macrophages. Interestingly, both strains showed similar amounts of intracellular reactive oxygen species. Finally, we observed a mutator phenotype and enhanced DNA transfer frequencies in the asrR deleted strain. These data indicate that AsrR plays a major role in antimicrobial resistance and

  11. Teaching in English-medium programmes

    DEFF Research Database (Denmark)

    Lauridsen, Karen M.; Cozart, Stacey Marie

    This contribution describes and discusses the module Teaching in English-medium programmes, an elective module offered as part of the teacher training programme for assistant professors (“adjunktpædagogikum”) at Aarhus University. In order to complete the whole programme, assistant professors must...... have at least one such elective module (http://upnet.au.dk/adjunktkursus/). Aarhus University offers the teacher training programme in Danish and in English for international faculty. Teaching in English-medium programmes is part of the Danish track, but taught through English. Building...... on the foundation module in the whole course, this particular module has been established especially for those Danish assistant professors who are to teach in the EMI programmes. The intended learning outcomes are that, at the end of the course, participants should be able to plan and deliver their teaching...

  12. Degradation of amaranth dye in alkaline medium by ultrasonic cavitation coupled with electrochemical oxidation using a boron-doped diamond anode

    International Nuclear Information System (INIS)

    Barros, Willyam R.P.; Steter, Juliana R.; Lanza, Marcos R.V.; Motheo, Artur J.

    2014-01-01

    Amaranth dye is used widely in the processing of paper, textiles, foods, cosmetics, beverages and medicines, and effluents contaminated with this compound are discharged daily into the environment. Recent studies have shown that azo dyes, especially those such as amaranth dye that have been classified as endocrine disruptors, may cause adverse effects to animal and human health. This paper describes the application of electrochemical oxidation (with a boron-doped diamond BDD thin-film anode) coupled with ultrasound sonolysis (20 kHz and 523 W cm −2 ) to the removal of amaranth dye from dilute alkaline solution. The electrochemical and sonoelectrochemical processes (ECh and SECh, respectively) were carried out at constant current density (10 to 50 mA cm −2 ) in a single compartment cylindrical cell. Sonolysis was virtually less useful for the decolorization and degradation of amaranth dye, whilst ECh and SECh were more effective in degrading the dye with almost complete removal (90 - 95%) attained after 90 min of experiment at an applied current density of 50 mA cm −2 . Degradation of the dye followed pseudo first-order kinetics in both processes, but the rate of reaction was faster with the SECh treatment confirming a synergistic effect between the cavitation process and the electrochemical system. Additionally, at low applied current densities (10 and 25 mA cm −2 ), SECh was considerably more effective than ECh for the amaranth dye mineralization. Although at 35 and 50 mA cm −2 , the two processes showed the respective removal of total organic carbon values: (i) 85% for the ECh and 90% for the SECh at 35 mA cm −2 ; (ii) 96% for the ECh and 98% for the SECh at 50 mA cm −2 . It is concluded that SECh presented the most favorable results for the decontamination of wastewaters containing azo dye compounds

  13. Zanthoxylum heitzii Modulates Ferric Nitrilotriacetate-Dependent Oxidative Alterations in Four Vital Organs: An In Vitro Organoprotective Model

    Science.gov (United States)

    Joël Essogo, Jacques; Tankeu, Francine Nzufo; Nanfack, Pauline

    2017-01-01

    Ferric nitrilotriacetate (Fe-NTA) is a highly reactive compound used to induce degenerative disorders through oxidative stress (OS). Zanthoxylum heitzii (Z. heitzii) is a spice used as a medicinal plant to treat a variety of illnesses. This study investigated the ability of extracts from the leaves, fruits, roots, and barks of Z. Heitzii to inhibit Fe-NTA mediated oxidative damage in rats. The supernatant of rat liver homogenates was pretreated with the extracts for one hour before the induction of oxidative damage using a solution of Fe-NTA (400 mM). The activities of superoxide dismutase (SOD), catalase, and peroxidases were measured together with the marker of lipid peroxidation and the level of glutathione. The pretreated groups showed a significant increase in the activity of SOD, catalase, and peroxidases. The methanolic extract from the leaves of Z. heitzii (36.78 ± 3.30) and aqueous extract from the fruits (37.01 ± 2.52) showed the highest activities of SOD in the liver. The lowest concentration of MDA was found in the liver, and the glutathione was greater in the brain. Conclusively, these results suggest that Z. heitzii might be a chemoprotector which may be used in for prevention of distinct types of diseases induced by oxidative stress. PMID:28852413

  14. Zanthoxylum heitzii Modulates Ferric Nitrilotriacetate-Dependent Oxidative Alterations in Four Vital Organs: An In Vitro Organoprotective Model

    Directory of Open Access Journals (Sweden)

    Jacques Joël Essogo

    2017-01-01

    Full Text Available Ferric nitrilotriacetate (Fe-NTA is a highly reactive compound used to induce degenerative disorders through oxidative stress (OS. Zanthoxylum heitzii (Z. heitzii is a spice used as a medicinal plant to treat a variety of illnesses. This study investigated the ability of extracts from the leaves, fruits, roots, and barks of Z. Heitzii to inhibit Fe-NTA mediated oxidative damage in rats. The supernatant of rat liver homogenates was pretreated with the extracts for one hour before the induction of oxidative damage using a solution of Fe-NTA (400 mM. The activities of superoxide dismutase (SOD, catalase, and peroxidases were measured together with the marker of lipid peroxidation and the level of glutathione. The pretreated groups showed a significant increase in the activity of SOD, catalase, and peroxidases. The methanolic extract from the leaves of Z. heitzii (36.78 ± 3.30 and aqueous extract from the fruits (37.01 ± 2.52 showed the highest activities of SOD in the liver. The lowest concentration of MDA was found in the liver, and the glutathione was greater in the brain. Conclusively, these results suggest that Z. heitzii might be a chemoprotector which may be used in for prevention of distinct types of diseases induced by oxidative stress.

  15. Chromium III histidinate exposure modulates antioxidant gene expression in HaCaT human keratinocytes exposed to oxidative stress

    Science.gov (United States)

    While the toxicity of hexavalent chromium is well established, trivalent Cr (Cr(III)) is an essential nutrient involved in insulin and glucose homeostasis. Recently, antioxidant effects of chromium (III) histidinate (Cr(III)His) were reported in HaCaT human keratinocytes exposed to oxidative stress...

  16. Investigating the role of Sirt1-modulated oxidative stress in relation to benign paroxysmal positional vertigo and Parkinson's disease.

    Science.gov (United States)

    Tsai, Kun-Ling; Cheng, Yuan-Yang; Leu, Hsin-Bang; Lee, Yi-Yen; Chen, Tzeng-Ji; Liu, Ding-Hao; Kao, Chung-Lan

    2015-09-01

    Benign paroxysmal positional vertigo (BPPV) is one of the most frequently encountered primary complaints in dizziness clinics. The incidence of BPPV has been proven to increase with age. The relationship between BPPV and another neurodegenerative disease, Parkinson's disease (PD), has not been previously discussed. This study aimed to investigate the relationship of BPPV and PD with oxidative stress. A total of 30,811 subjects participated in our cohort study. The study cohort comprised 5057 BPPV patients and a comparison cohort of 25,754 nonBPPV patients. SIRT1 axis gene expression was investigated in BPPV patient blood samples and a PD cell model of 6-hydroxydopamine (6-OHDA)-treated PC-12 cells to elucidate the potential in vitro and in vivo mechanisms of degeneration in PD and BPPV. Our data suggest that BPPV patients with histories of head injuries show a significantly higher hazard to develop subsequent PD (hazard ratio, 3.942; confidence interval, 1.523-10.205, p = 0.005). We also observed that oxidative status is increased in blood samples from patients with BPPV. Our in vitro study suggests that SIRT1 function is inhibited by oxidative stress, which thereby promotes 6-hydroxydopamine-induced cell death. We conclude that BPPV is independently associated with an increased risk of PD. This finding may be attributed to oxidative stress-mediated inhibition of SIRT1 expression levels. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Transition metal alloy-modulated lithium manganese oxide nanosystem for energy storage in lithium-ion battery cathodes

    CSIR Research Space (South Africa)

    West, N

    2013-07-01

    Full Text Available . The material crystallite size was 10 nm with clear lattice fringes having a separation value of 0.48 nm which concurrently improved the diffusion rate of Li(sup+). Solid-state NMR results showed the progressive increase in average nominal manganese oxidation...

  18. Ameliorative Effect of Daidzein on Cisplatin-Induced Nephrotoxicity in Mice via Modulation of Inflammation, Oxidative Stress, and Cell Death

    Directory of Open Access Journals (Sweden)

    Hongzhou Meng

    2017-01-01

    Full Text Available Oxidative stress and inflammation are part and parcel of cisplatin-induced nephrotoxicity. The purpose of this work is to study the role of soy isoflavone constituent, daidzein, in cisplatin-induced renal damage. Cisplatin-induced nephrotoxicity was evident by the histological damage in proximal tubular cells and by the increase in serum neutrophil gelatinase-associated lipocalin (NGAL, blood urea nitrogen (BUN, creatinine, and urinary kidney injury molecule-1 (KIM-1. Cisplatin-induced cell death was shown by TUNEL staining and caspase-3/7 activity. Daidzin treatment reduced all kidney injury markers (NGAL, BUN, creatinine, and KIM-1 and attenuated cell death (apoptotic markers. In cisplatin-induced kidney injury, renal oxidative/nitrative stress was manifested by the increase in lipid peroxidation and protein nitration. Cisplatin induced the reactive oxygen species-generating enzyme NOX-2 and impaired antioxidant defense enzyme activities such as glutathione peroxidase (GPX and superoxide dismutase (SOD activities. Cisplatin-induced oxidative/nitrative stress was attenuated by daidzein treatment. Cisplatin induced CD11b-positive macrophages in kidneys and daidzein attenuated CD11b-positive cells. Daidzein attenuated cisplatin-induced inflammatory cytokines tumor necrosis factor α (TNFα, interleukin 10 (IL-10, interleukin 18 (IL-18, and monocyte chemoattractant protein-1 (MCP-1. Daidzein attenuated cell death in vitro. Our data suggested that daidzein attenuated cisplatin-induced kidney injury through the downregulation of oxidative/nitrative stress, immune cells, inflammatory cytokines, and apoptotic cell death, thus improving kidney regeneration.

  19. Paranode Abnormalities and Oxidative Stress in Optic Nerve Vulnerable to Secondary Degeneration: Modulation by 670 nm Light Treatment.

    Directory of Open Access Journals (Sweden)

    Charis R Szymanski

    Full Text Available Secondary degeneration of nerve tissue adjacent to a traumatic injury results in further loss of neurons, glia and function, via mechanisms that may involve oxidative stress. However, changes in indicators of oxidative stress have not yet been demonstrated in oligodendrocytes vulnerable to secondary degeneration in vivo. We show increases in the oxidative stress indicator carboxymethyl lysine at days 1 and 3 after injury in oligodendrocytes vulnerable to secondary degeneration. Dihydroethidium staining for superoxide is reduced, indicating endogenous control of this particular reactive species after injury. Concurrently, node of Ranvier/paranode complexes are altered, with significant lengthening of the paranodal gap and paranode as well as paranode disorganisation. Therapeutic administration of 670 nm light is thought to improve oxidative metabolism via mechanisms that may include increased activity of cytochrome c oxidase. Here, we show that light at 670 nm, delivered for 30 minutes per day, results in in vivo increases in cytochrome c oxidase activity co-localised with oligodendrocytes. Short term (1 day 670 nm light treatment is associated with reductions in reactive species at the injury site. In optic nerve vulnerable to secondary degeneration superoxide in oligodendrocytes is reduced relative to handling controls, and is associated with reduced paranode abnormalities. Long term (3 month administration of 670 nm light preserves retinal ganglion cells vulnerable to secondary degeneration and maintains visual function, as assessed by the optokinetic nystagmus visual reflex. Light at a wavelength of 670 nm may serve as a therapeutic intervention for treatment of secondary degeneration following neurotrauma.

  20. Cereal based diets modulate some markers of oxidative stress and inflammation in lean and obese Zucker rats

    Directory of Open Access Journals (Sweden)

    Mano Mark

    2011-05-01

    Full Text Available Abstract Background The potential of cereals with high antioxidant capacity for reducing oxidative stress and inflammation in obesity is unknown. This study investigated the impact of wheat bran, barley or a control diet (α-cellulose on the development of oxidative stress and inflammation in lean and obese Zucker rats. Methods Seven wk old, lean and obese male Zucker rats (n = 8/group were fed diets that contained wheat bran, barley or α-cellulose (control. After 3 months on these diets, systolic blood pressure was measured and plasma was analysed for glucose, insulin, lipids, oxygen radical absorbance capacity (ORAC, malondialdehyde, glutathione peroxidase and adipokine concentration (leptin, adiponectin, interleukin (IL-1β, IL-6, TNFα, plasminogen activator inhibitor (PAI-1, monocyte chemotactic protein (MCP-1. Adipokine secretion rates from visceral and subcutaneous adipose tissue explants were also determined. Results Obese rats had higher body weight, systolic blood pressure and fasting blood lipids, glucose, insulin, leptin and IL-1β in comparison to lean rats, and these measures were not reduced by consumption of wheat bran or barley based diets. Serum ORAC tended to be higher in obese rats fed wheat bran and barley in comparison to control (p = 0.06. Obese rats had higher plasma malondialdehyde (p Conclusions A 3-month dietary intervention was sufficient for Zucker obese rats to develop oxidative stress and systemic inflammation. Cereal-based diets with moderate and high antioxidant capacity elicited modest improvements in indices of oxidative stress and inflammation.

  1. MnTM-4-PyP modulates endogenous antioxidant responses and protects primary cortical neurons against oxidative stress.

    Science.gov (United States)

    Cheng, Kuo-Yuan; Guo, Fei; Lu, Jia-Qi; Cao, Yuan-Zhao; Wang, Tian-Chang; Yang, Qi; Xia, Qing

    2015-05-01

    Oxidative stress is a direct cause of injury in various neural diseases. Manganese porphyrins (MnPs), a large category of superoxide dismutase (SOD) mimics, shown universally to have effects in numerous neural disease models in vivo. Given their complex intracellular redox activities, detailed mechanisms underlying the biomedical efficacies are not fully elucidated. This study sought to investigate the regulation of endogenous antioxidant systems by a MnP (MnTM-4-PyP) and its role in the protection against neural oxidative stress. Primary cortical neurons were treated with MnTM-4-PyP prior to hydrogen peroxide-induced oxidative stress. MnTM-4-PyP increased cell viability, reduced intracellular level of reactive oxygen species, inhibited mitochondrial apoptotic pathway, and ameliorated endoplasmic reticulum function. The protein levels and activities of endogenous SODs were elevated, but not those of catalase. SOD2 transcription was promoted in a transcription factor-specific manner. Additionally, we found FOXO3A and Sirt3 levels also increased. These effects were not observed with MnTM-4-PyP alone. Induction of various levels of endogenous antioxidant responses by MnTM-4-PyP has indispensable functions in its protection for cortical neurons against hydrogen peroxide-induced oxidative stress. © 2014 John Wiley & Sons Ltd.

  2. An antiinflammatory dietary mix modulates inflammation and oxidative and metabolic stress in overweight men: A nutrigenomics approach

    NARCIS (Netherlands)

    Bakker, G.C.M.; Erk, M.J. van; Pellis, L.; Wopereis, S.; Rubingh, C.M.; Cnubben, N.H.P.; Kooistra, T.; Ommen, B. van; Hendriks, H.F.J.

    2010-01-01

    Background: Low-grade chronic inflammation in overweight subjects is thought to play an important role in disease development. Objective: It was hypothesized that specific dietary components are able to reduce low-grade inflammation as well as metabolic and oxidative stress. Design: Dietary products

  3. Inhibition of UVA-mediated melanogenesis by ascorbic acid through modulation of antioxidant defense and nitric oxide system.

    Science.gov (United States)

    Panich, Uraiwan; Tangsupa-a-nan, Vanida; Onkoksoong, Tasanee; Kongtaphan, Kamolratana; Kasetsinsombat, Kanda; Akarasereenont, Pravit; Wongkajornsilp, Adisak

    2011-05-01

    Ascorbic acid (AA) has been well known as a skin whitening agent, although attempts have been made to evaluate its protective role against ultraviolet (UV)-induced skin hyperpigmentation or increased melanin production. While melanogenesis is a defense mechanism of the skin against UV irradiation, melanin overproduction may also contribute to melanoma initiation. UVA might play a role in melanogenesis through promoting oxidative stress, which occurs as the result of increased formation of oxidants and/or reactive nitrogen species (RNS) including nitric oxide (NO). Therefore, we investigated the antimelanogenic effect of AA (7.5-120 μM) in association with its inhibitory effect on UVA-induced oxidant formation, NO production through endothelial and inducible NO synthases (eNOS and iNOS) activation and impairment of antioxidant defense using G361 human melanoma cells. Our study demonstrated a comparable ability of AA with that of kojic acid, a well-known tyrosinase inhibitor in inhibiting mushroom tyrosinase. Melanin content was reduced by AA, but neither tyrosinase activity nor mRNA levels were reduced by AA at non-cytotoxic concentrations in UVA-irradiated G361 cells. AA was shown to inhibit UVA-mediated catalase (CAT) inactivation, glutathione (GSH) depletion, oxidant formation and NO production through suppression of eNOS and iNOS mRNA. We report herein that AA can protect against UVA-dependent melanogenesis possibly through the improvement of antioxidant defense capacity and inhibition of NO production through down-regulation of eNOS and iNOS mRNA.

  4. Rosiglitazone inhibits chlorpyrifos-induced apoptosis via modulation of the oxidative stress and inflammatory response in SH-SY5Y cells

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Eun [Department of Pharmacology, College of Medicine, Hanyang University, Seoul (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Park, Jae Hyeon; Jang, Sea Jeong [Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of); Koh, Hyun Chul, E-mail: hckoh@hanyang.ac.kr [Department of Pharmacology, College of Medicine, Hanyang University, Seoul (Korea, Republic of); Hanyang Biomedical Research Institute, Seoul (Korea, Republic of); Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul (Korea, Republic of)

    2014-07-15

    Oxidative stress can lead to expression of inflammatory transcription factors, which are important regulatory elements in the induction of inflammatory responses. One of the transcription factors, nuclear transcription factor kappa-B (NF-κB) plays a significant role in the inflammation regulatory process. Inflammatory cell death has been implicated in neuronal cell death in some neurodegenerative disorders such as Parkinson's disease (PD). In this study, we investigated the molecular mechanisms underlying apoptosis initiated by chlorpyrifos (CPF)-mediated oxidative stress. Based on the cytotoxic mechanism of CPF, we examined the neuroprotective effects of rosiglitazone (RGZ), a peroxisome proliferator-activated receptor gamma (PPAR-γ) agonist, against CPF-induced neuronal cell death. The treatment of SH-SY5Y cells with CPF induced oxidative stress. In addition, CPF activated the p38, JNK and ERK mitogen-activated protein kinases (MAPKs), and induced increases in the inflammatory genes such as COX-2 and TNF-α. CPF also induced nuclear translocation of NF-κB and inhibitors of NF-κB abolished the CPF-induced COX-2 expression. Pretreatment with RGZ significantly reduced ROS generation and enhanced HO-1 expression in CPF-exposed cells. RGZ blocked the activation of both p38 and JNK signaling, while ERK activation was strengthened. RGZ also attenuated CPF-induced cell death through the reduction of NF-κB-mediated proinflammatory factors. Results from this study suggest that RGZ may exert an anti-apoptotic effect against CPF-induced cytotoxicity by attenuation of oxidative stress as well as inhibition of the inflammatory cascade via inactivation of signaling by p38 and JNK, and NF-κB. - Highlights: • CPF induces apoptotic cell death in SH-SY5Y cells • ROS involved in CPF-mediated apoptotic cell death • Inflammation involved in CPF-mediated apoptotic cell death • Rosiglitazone modulates ROS and inflammatory response in CPF-treated cells.

  5. Chronic treatment with taurine after intracerebroventricular streptozotocin injection improves cognitive dysfunction in rats by modulating oxidative stress, cholinergic functions and neuroinflammation.

    Science.gov (United States)

    Reeta, K H; Singh, Devendra; Gupta, Y K

    2017-09-01

    The present study investigated the neuroprotective effects of taurine, an essential amino acid for growth and development of central nervous system. Intracerebroventricular streptozotocin (ICV-STZ) model of cognitive impairment was used in male Wistar rats (270 ± 20 g). Morris water maze, elevated plus maze and passive avoidance paradigm were used to assess cognitive performance. Taurine (40, 60 and 120 mg/kg) was administered orally for 28 days following STZ administration on day 1. Oxidative stress parameters (malondialdehyde, glutathione, nitric oxide and superoxide dismutase) and cholinesterases (acetylcholinesterase and butyrylcholinesterase) activity were measured at end of the study in the cortex and hippocampus. Levels of TNF-α, IL-1β, expression of rho kinase-II (ROCK-II), glycogen synthase kinase-3β (GSK-3β) and choline acetyltransferase (ChAT) were studied in cortex and hippocampus. STZ caused significant cognitive impairment as compared to normal control. Chronic administration of taurine attenuated STZ-induced cognitive impairment. Increased oxidative stress and increased levels of TNF-α, IL-1β induced by STZ were also significantly attenuated by taurine. Taurine significantly (p taurine. STZ decreased the expression of ChAT in hippocampus which was significantly (p taurine. However, GSK-3β expression was not altered by either STZ or taurine. The present study indicates that taurine exerts a neuroprotective role against STZ-induced cognitive impairment in rats. This effect is probably mediated by modulating oxidative stress, cholinesterases, inflammatory cytokines and expression of ROCK-II. Thus, this study suggests a potential of chronic taurine administration in cognitive impairment of Alzheimer's type. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. Prohibitin confers cytoprotection against ISO-induced hypertrophy in H9c2 cells via attenuation of oxidative stress and modulation of Akt/Gsk-3β signaling.

    Science.gov (United States)

    Chowdhury, Debabrata; Kumar, Dinesh; Bhadra, Utpal; Devi, Tangutur Anjana; Bhadra, Manika Pal

    2017-01-01

    Numerous hypertrophic stimuli, including β-adrenergic agonists such as isoproterenol (ISO), result in generation of reactive oxygen species (ROS) and alteration in the mitochondrial membrane potential (Δψ) leading to oxidative stress. This process is well associated with phosphorylation of thymoma viral proto-oncogene Akt (Ser473) and glycogen synthase kinase-3β (Gsk-3β) (Ser9), with resultant inactivation of Gsk-3β. In the present study, we found that the protective defensive role of prohibitin (PHB) against ISO-induced hypertrophic response in rat H9c2 cells is via attenuation of oxidative stress-dependent signaling pathways. The intracellular levels of mitochondrial membrane potential along with cellular ROS levels and mitochondrial superoxide generation were determined. In order to understand the regulation of Akt/Gsk-3β signaling pathway, we carried out immmunoblotting for key proteins of the pathway such as PTEN, PI3K, phosphorylated, and unphosphorylated forms of Akt, Gsk-3β, and immunofluorescence experiments of p-Gsk-3β. Enforced expression of PHB in ISO-treated H9c2 cells suppressed cellular ROS production with mitochondrial superoxide generation and enhanced the mitochondrial membrane potential resulting in suppression of oxidative stress which likely offered potent cellular protection, led to the availability of more healthy cells, and also, significant constitutive activation of Gsk-3β via inactivation of Akt was observed. Knockdown of PHB expression using PHB siRNA in control H9c2 cells reversed these effects. Overall, our results demonstrate that PHB confers cytoprotection against oxidative stress in ISO-induced hypertrophy and this process is associated with modulation of Akt/Gsk-3β signaling mechanisms as evident from our PHB overexpression and knockdown experiments.

  7. Comparison between transient and frequency modulated excitation: application to silicon nitride and aluminum oxide coatings of silicon.

    Science.gov (United States)

    Klein, D; Ohm, W; Fengler, S; Kunst, M

    2014-06-01

    Contactless measurements of the lifetime of charge carriers are presented with varying ways of photo excitation: with and without bias light and pulsed and frequency modulated. These methods are applied to the study of the surface passivation of single crystalline silicon by a-SiN(x):H and Al2O3 coatings. The properties of these coatings are investigated under consideration of the merits of the different methods.

  8. Development of Nanofiller-Modulated Polymeric Oxygen Enrichment Membranes for Reduction of Nitrogen Oxides in Coal Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Jianzhong Lou; Shamsuddin Ilias

    2010-12-31

    North Carolina A&T State University in Greensboro, North Carolina, has undertaken this project to develop the knowledge and the material to improve the oxygen-enrichment polymer membrane, in order to provide high-grade oxygen-enriched streams for coal combustion and gasification applications. Both experimental and theoretical approaches were used in this project. The membranes evaluated thus far include single-walled carbon nano-tube, nano-fumed silica polydimethylsiloxane (PDMS), and zeolite-modulated polyimide membranes. To document the nanofiller-modulated polymer, molecular dynamics simulations have been conducted to calculate the theoretical oxygen molecular diffusion coefficient and nitrogen molecular coefficient inside single-walled carbon nano-tube PDMS membranes, in order to predict the effect of the nano-tubes on the gas-separation permeability. The team has performed permeation and diffusion experiments using polymers with nano-silica particles, nano-tubes, and zeolites as fillers; studied the influence of nano-fillers on the self diffusion, free volume, glass transition, oxygen diffusion and solubility, and perm-selectivity of oxygen in polymer membranes; developed molecular models of single-walled carbon nano-tube and nano-fumed silica PDMS membranes, and zeolites-modulated polyimide membranes. This project partially supported three graduate students (two finished degrees and one transferred to other institution). This project has resulted in two journal publications and additional publications will be prepared in the near future.

  9. Silymarin modulates doxorubicin-induced oxidative stress, Bcl-xL and p53 expression while preventing apoptotic and necrotic cell death in the liver

    International Nuclear Information System (INIS)

    Patel, Nirav; Joseph, Cecil; Corcoran, George B.; Ray, Sidhartha D.

    2010-01-01

    The emergence of silymarin (SMN) as a natural remedy for liver diseases, coupled with its entry into NIH clinical trial, signifies its hepatoprotective potential. SMN is noted for its ability to interfere with apoptotic signaling while acting as an antioxidant. This in vivo study was designed to explore the hepatotoxic potential of Doxorubicin (Dox), the well-known cardiotoxin, and in particular whether pre-exposures to SMN can prevent hepatotoxicity by reducing Dox-induced free radical mediated oxidative stress, by modulating expression of apoptotic signaling proteins like Bcl-xL, and by minimizing liver cell death occurring by apoptosis or necrosis. Groups of male ICR mice included Control, Dox alone, SMN alone, and Dox with SMN pre/co-treatment. Control and Dox groups received saline i.p. for 14 days. SMN was administered p.o. for 14 days at 16 mg/kg/day. An approximate LD 50 dose of Dox, 60 mg/kg, was administered i.p. on day 12 to animals receiving saline or SMN. Animals were euthanized 48 h later. Dox alone induced frank liver injury (> 50-fold increase in serum ALT) and oxidative stress (> 20-fold increase in malondialdehyde [MDA]), as well as direct damage to DNA (> 15-fold increase in DNA fragmentation). Coincident genomic damage and oxidative stress influenced genomic stability, reflected in increased PARP activity and p53 expression. Decreases in Bcl-xL protein coupled with enhanced accumulation of cytochrome c in the cytosol accompanied elevated indexes of apoptotic and necrotic cell death. Significantly, SMN exposure reduced Dox hepatotoxicity and associated apoptotic and necrotic cell death. The effects of SMN on Dox were broad, including the ability to modulate changes in both Bcl-xL and p53 expression. In animals treated with SMN, tissue Bcl-xL expression exceeded control values after Dox treatment. Taken together, these results demonstrated that SMN (i) reduced, delayed onset, or prevented toxic effects of Dox which are typically associated with

  10. Nitric oxide triggers a concentration-dependent differential modulation of superoxide dismutase (FeSOD and Cu/ZnSOD) activity in sunflower seedling roots and cotyledons as an early and long distance signaling response to NaCl stress.

    Science.gov (United States)

    Arora, Dhara; Bhatla, Satish C

    2015-01-01

    Dark-grown sunflower (Helianthus annuus L.) seedlings exhibit modulation of total superoxide dismutase (SOD;EC 1.15.1.1) activity in roots and cotyledons (10,000g supernatant) in response to salt stress (NaCl; 120 mM) through a differential, zymographically detectable, whole tissue activity of FeSOD and Cu/ZnSOD. Confocal laser scanning microscopic imaging (CLSM) has further shown that NaCl stress significantly influences differential spatial distribution of Cu/ZnSOD and MnSOD isoforms in an inverse manner. Dual action of nitric oxide (NO) is evident in its crosstalk with FeSOD and Cu/ZnSOD in seedling roots and cotyledons in control and NaCl(-) stress conditions. Cu/ZnSOD activity in the roots of 2 d old NaCl(-) stressed seedlings is enhanced in the presence of 125-1000 µM of NO donor (sodium nitroprusside; SNP) indicating salt sensitivity of the enzyme activity. Quenching of endogenous NO by cPTIO treatment (500, 1000 µM) lowers FeSOD activity in roots (-NaCl). Cotyledons from control seedlings show an upregulation of FeSOD activity with increasing availability of SNP (125-1000 µM) in the Hoagland irrigation medium. Quenching of NO by cPTIO provides evidence for an inverse correlation between NO availability and FeSOD activity in seedling cotyledons irrespective of NaCl stress. Variable response due to NO on SOD isoforms in sunflower seedlings reflects its concentration-dependent biphasic (pro- and antioxidant) nature of action. Differential induction of SOD isoforms by NO indicates separate intracellular signaling pathways (associated with their respective functional separation) operative in seedling roots as an early salt stress mechanism and in cotyledons as an early long-distance NaCl stress sensing mechanism.

  11. Krebs Cycle Intermediates Protective against Oxidative Stress by Modulating the Level of Reactive Oxygen Species in Neuronal HT22 Cells.

    Science.gov (United States)

    Sawa, Kenta; Uematsu, Takumi; Korenaga, Yusuke; Hirasawa, Ryuya; Kikuchi, Masatoshi; Murata, Kyohei; Zhang, Jian; Gai, Xiaoqing; Sakamoto, Kazuichi; Koyama, Tomoyuki; Satoh, Takumi

    2017-03-16

    Krebs cycle intermediates (KCIs) are reported to function as energy substrates in mitochondria and to exert antioxidants effects on the brain. The present study was designed to identify which KCIs are effective neuroprotective compounds against oxidative stress in neuronal cells. Here we found that pyruvate, oxaloacetate, and α-ketoglutarate, but not lactate, citrate, iso-citrate, succinate, fumarate, or malate, protected HT22 cells against hydrogen peroxide-mediated toxicity. These three intermediates reduced the production of hydrogen peroxide-activated reactive oxygen species, measured in terms of 2',7'-dichlorofluorescein diacetate fluorescence. In contrast, none of the KCIs-used at 1 mM-protected against cell death induced by high concentrations of glutamate-another type of oxidative stress-induced neuronal cell death. Because these protective KCIs did not have any toxic effects (at least up to 10 mM), they have potential use for therapeutic intervention against chronic neurodegenerative diseases.

  12. Oxidative stress and antioxidant activity in hypothermia and rewarming: can RONS modulate the beneficial effects of therapeutic hypothermia?

    Science.gov (United States)

    Alva, Norma; Palomeque, Jesús; Carbonell, Teresa

    2013-01-01

    Hypothermia is a condition in which core temperature drops below the level necessary to maintain bodily functions. The decrease in temperature may disrupt some physiological systems of the body, including alterations in microcirculation and reduction of oxygen supply to tissues. The lack of oxygen can induce the generation of reactive oxygen and nitrogen free radicals (RONS), followed by oxidative stress, and finally, apoptosis and/or necrosis. Furthermore, since the hypothermia is inevitably followed by a rewarming process, we should also consider its effects. Despite hypothermia and rewarming inducing injury, many benefits of hypothermia have been demonstrated when used to preserve brain, cardiac, hepatic, and intestinal function against ischemic injury. This review gives an overview of the effects of hypothermia and rewarming on the oxidant/antioxidant balance and provides hypothesis for the role of reactive oxygen species in therapeutic hypothermia.

  13. Oxidative Stress and Antioxidant Activity in Hypothermia and Rewarming: Can RONS Modulate the Beneficial Effects of Therapeutic Hypothermia?

    Directory of Open Access Journals (Sweden)

    Norma Alva

    2013-01-01

    Full Text Available Hypothermia is a condition in which core temperature drops below the level necessary to maintain bodily functions. The decrease in temperature may disrupt some physiological systems of the body, including alterations in microcirculation and reduction of oxygen supply to tissues. The lack of oxygen can induce the generation of reactive oxygen and nitrogen free radicals (RONS, followed by oxidative stress, and finally, apoptosis and/or necrosis. Furthermore, since the hypothermia is inevitably followed by a rewarming process, we should also consider its effects. Despite hypothermia and rewarming inducing injury, many benefits of hypothermia have been demonstrated when used to preserve brain, cardiac, hepatic, and intestinal function against ischemic injury. This review gives an overview of the effects of hypothermia and rewarming on the oxidant/antioxidant balance and provides hypothesis for the role of reactive oxygen species in therapeutic hypothermia.

  14. Krebs Cycle Intermediates Protective against Oxidative Stress by Modulating the Level of Reactive Oxygen Species in Neuronal HT22 Cells

    Directory of Open Access Journals (Sweden)

    Kenta Sawa

    2017-03-01

    Full Text Available Krebs cycle intermediates (KCIs are reported to function as energy substrates in mitochondria and to exert antioxidants effects on the brain. The present study was designed to identify which KCIs are effective neuroprotective compounds against oxidative stress in neuronal cells. Here we found that pyruvate, oxaloacetate, and α-ketoglutarate, but not lactate, citrate, iso-citrate, succinate, fumarate, or malate, protected HT22 cells against hydrogen peroxide-mediated toxicity. These three intermediates reduced the production of hydrogen peroxide-activated reactive oxygen species, measured in terms of 2′,7′-dichlorofluorescein diacetate fluorescence. In contrast, none of the KCIs—used at 1 mM—protected against cell death induced by high concentrations of glutamate—another type of oxidative stress-induced neuronal cell death. Because these protective KCIs did not have any toxic effects (at least up to 10 mM, they have potential use for therapeutic intervention against chronic neurodegenerative diseases.

  15. Taraxacum officinale Weber extracts inhibit LPS-induced oxidative stress and nitric oxide production via the NF-κB modulation in RAW 264.7 cells.

    Science.gov (United States)

    Park, Chung Mu; Park, Ji Young; Noh, Kyung Hee; Shin, Jin Hyuk; Song, Young Sun

    2011-01-27

    The common dandelion (Taraxacum officinale G.H. Weber ex Wiggers, Asteraceae) has been widely used in folklore medicine to treat dyspepsia, heartburn, and spleen and liver disorders. To compare the antioxidative and anti-inflammatory activities of Taraxacum officinale methanol extract (TOME) and water extract (TOWE) in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells and assess their constitutional differences, including luteolin, chicoric acid, and total phenol content. Antioxidative enzyme activities, nitric oxide (NO) production, and inducible NO synthase (iNOS) and nuclear factor (NF)-κB expression were estimated by biochemical analysis, the Griess reaction, reverse transcription-polymerase chain reaction, western hybridization, and electrophoretic mobility shift assay. High-performance liquid chromatography and the Folin-Ciocalteau method were used to analyze functional phytochemicals and total phenol content. TOME and TOWE significantly reduced NO production with an IC(50) of 79.9 and 157.5 μg/mL, respectively, without cytotoxicity. Depleted glutathione (GSH) and antioxidative enzyme activities, including superoxide dismutase, catalase, GSH-peroxidase, and GSH-reductase, were restored by dandelion extracts. Both extracts inhibited LPS-stimulated iNOS gene expression and that of its transcription factor, NF-κB, in parallel with nitrite reduction. TOME showed more potent antioxidative and anti-inflammatory capacities than TOWE, which was attributable to its high total phenol, luteolin, and chicoric acid content. These results indicate that TOME and TOWE inhibit oxidative stress and inflammatory responses through elevated de novo synthesis of antioxidative enzymes and suppression of iNOS expression by NF-κB inactivation. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  16. Carvedilol alleviates adjuvant-induced arthritis and subcutaneous air pouch edema: Modulation of oxidative stress and inflammatory mediators

    International Nuclear Information System (INIS)

    Arab, Hany H.; El-Sawalhi, Maha M.

    2013-01-01

    Rheumatoid arthritis (RA) is a systemic inflammatory disease with cardiovascular complications as the leading cause of morbidity. Carvedilol is an adrenergic antagonist which has been safely used in treatment of several cardiovascular disorders. Given that carvedilol has powerful antioxidant/anti-inflammatory properties, we aimed to investigate its protective potential against arthritis that may add further benefits for its clinical usefulness especially in RA patients with concomitant cardiovascular disorders. Two models were studied in the same rat; adjuvant arthritis and subcutaneous air pouch edema. Carvedilol (10 mg/kg/day p.o. for 21 days) effectively suppressed inflammation in both models with comparable efficacy to the standard anti-inflammatory diclofenac (5 mg/kg/day p.o.). Notably, carvedilol inhibited paw edema and abrogated the leukocyte invasion to air pouch exudates. The latter observation was confirmed by the histopathological assessment of the pouch lining that revealed mitigation of immuno-inflammatory cell influx. Carvedilol reduced/normalized oxidative stress markers (lipid peroxides, nitric oxide and protein thiols) and lowered the release of inflammatory cytokines (TNF-α and IL-6), and eicosanoids (PGE 2 and LTB 4 ) in sera and exudates of arthritic rats. Interestingly, carvedilol, per se, didn't present any effect on assessed biochemical parameters in normal rats. Together, the current study highlights evidences for the promising anti-arthritic effects of carvedilol that could be mediated through attenuation of leukocyte migration, alleviation of oxidative stress and suppression of proinflammatory cytokines and eicosanoids. - Highlights: ► Carvedilol possesses promising anti-arthritic properties. ► It markedly suppressed inflammation in adjuvant arthritis and air pouch edema. ► It abrogated the leukocyte invasion to air pouch exudates and linings. ► It reduced/normalized oxidative stress markers in sera and exudates of arthritic rats

  17. Carvedilol alleviates adjuvant-induced arthritis and subcutaneous air pouch edema: Modulation of oxidative stress and inflammatory mediators

    Energy Technology Data Exchange (ETDEWEB)

    Arab, Hany H., E-mail: hany_h_arab@yahoo.com [Biochemistry Division, Department of Pharmacology and Toxicology, Faculty of Pharmacy, Taif University, Taif (Saudi Arabia); Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo (Egypt); El-Sawalhi, Maha M. [Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo (Egypt)

    2013-04-15

    Rheumatoid arthritis (RA) is a systemic inflammatory disease with cardiovascular complications as the leading cause of morbidity. Carvedilol is an adrenergic antagonist which has been safely used in treatment of several cardiovascular disorders. Given that carvedilol has powerful antioxidant/anti-inflammatory properties, we aimed to investigate its protective potential against arthritis that may add further benefits for its clinical usefulness especially in RA patients with concomitant cardiovascular disorders. Two models were studied in the same rat; adjuvant arthritis and subcutaneous air pouch edema. Carvedilol (10 mg/kg/day p.o. for 21 days) effectively suppressed inflammation in both models with comparable efficacy to the standard anti-inflammatory diclofenac (5 mg/kg/day p.o.). Notably, carvedilol inhibited paw edema and abrogated the leukocyte invasion to air pouch exudates. The latter observation was confirmed by the histopathological assessment of the pouch lining that revealed mitigation of immuno-inflammatory cell influx. Carvedilol reduced/normalized oxidative stress markers (lipid peroxides, nitric oxide and protein thiols) and lowered the release of inflammatory cytokines (TNF-α and IL-6), and eicosanoids (PGE{sub 2} and LTB{sub 4}) in sera and exudates of arthritic rats. Interestingly, carvedilol, per se, didn't present any effect on assessed biochemical parameters in normal rats. Together, the current study highlights evidences for the promising anti-arthritic effects of carvedilol that could be mediated through attenuation of leukocyte migration, alleviation of oxidative stress and suppression of proinflammatory cytokines and eicosanoids. - Highlights: ► Carvedilol possesses promising anti-arthritic properties. ► It markedly suppressed inflammation in adjuvant arthritis and air pouch edema. ► It abrogated the leukocyte invasion to air pouch exudates and linings. ► It reduced/normalized oxidative stress markers in sera and exudates of

  18. Hypoxic transcription gene profiles under the modulation of nitric oxide in nuclear run on-microarray and proteomics

    OpenAIRE

    Igwe, Emeka I.; Essler, Silke; Al-Furoukh, Natalie; Dehne, Nathalie; Brüne, Bernhard

    2009-01-01

    Abstract Background Microarray analysis still is a powerful tool to identify new components of the transcriptosome. It helps to increase the knowledge of targets triggered by stress conditions such as hypoxia and nitric oxide. However, analysis of transcriptional regulatory events remain elusive due to the contribution of altered mRNA stability to gene expression patterns as well as changes in the half-life of mRNAs, which influence mRNA expression levels and their turn over rates. To circumv...

  19. Extreme mobility enhancement of two-dimensional electron gases at oxide interfaces via charge transfer induced modulation doping

    DEFF Research Database (Denmark)

    Chen, Yunzhong; Trier, Felix; Wijnands, T.

    2015-01-01

    as applied research of complex oxides. Here, we inserted a single unit cell insulating layer of polar La1-xSrxMnO3 (x=0, 1/8, and 1/3) at the interface between disordered LaAlO3 and crystalline SrTiO3 created at room temperature. We find that the electron mobility of the interfacial 2DEG is enhanced by more...

  20. Iron oxide nanoparticles modulate heat shock proteins and organ specific markers expression in mice male accessory organs.

    Science.gov (United States)

    Sundarraj, Kiruthika; Raghunath, Azhwar; Panneerselvam, Lakshmikanthan; Perumal, Ekambaram

    2017-02-15

    With increased industrial utilization of iron oxide nanoparticles (Fe 2 O 3 -NPs), concerns on adverse reproductive health effects following exposure have been immensely raised. In the present study, the effects of Fe 2 O 3 -NPs exposure in the seminal vesicle and prostate gland were studied in mice. Mice were exposed to two different doses (25 and 50 mg/kg) of Fe 2 O 3 -NPs along with the control and analyzed the expressions of heat shock proteins (HSP60, HSP70 and HSP90) and organ specific markers (Caltrin, PSP94, and SSLP1). Fe 2 O 3 -NPs decreased food consumption, water intake, and organo-somatic index in mice with elevated iron levels in serum, urine, fecal matter, seminal vesicle and prostate gland. FTIR spectra revealed alterations in the functional groups of biomolecules on Fe 2 O 3 -NPs treatment. These changes are accompanied by increased lactate dehydrogenase levels with decreased total protein and fructose levels. The investigation of oxidative stress biomarkers demonstrated a significant increase in reactive oxygen species, nitric oxide, lipid peroxidation, protein carbonyl content and glutathione peroxidase with a concomitant decrement in the glutathione and ascorbic acid in the male accessory organs which confirmed the induction of oxidative stress. An increase in NADPH-oxidase-4 with a decrease in glutathione-S-transferase was observed in the seminal vesicle and prostate gland of the treated groups. An alteration in HSP60, HSP70, HSP90, Caltrin, PSP94, and SSLP1 expression was also observed. Moreover, accumulation of Fe 2 O 3 -NPs brought pathological changes in the seminal vesicle and prostate gland of treated mice. These findings provide evidence that Fe 2 O 3 -NPs could be an environmental risk factor for reproductive disease. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Saffron supplements modulate serum pro-oxidant-antioxidant balance in patients with metabolic syndrome: A randomized, placebo-controlled clinical trial

    Directory of Open Access Journals (Sweden)

    Tayyebeh Kermani

    2015-08-01

    Full Text Available Objectives: We have investigated the effect of a saffron supplement, given at a dose of 100 mg/kg, on prooxidant-antioxidant balance (PAB in individuals with metabolic syndrome. Materials and Methods: A randomized, placebo-controlled trial design was used in 75 subjects with metabolic syndrome who were randomly allocated to one of two study groups: (1 the case group received 100mg/kg saffron and (2 the placebo control group received placebo for 12 weeks. The serum PAB assay was applied to all subjects before (week 0 and after (weeks 6 and 12 the intervention. Results: There was a significant (p=0.035 reduction in serum PAB between week 0 to week 6 and also from week 0 to week 12.  Conclusion: Saffron supplements can modulate serum PAB in subjects with metabolic syndrome, implying an improvement in some aspects of oxidative stress or antioxidant protection.

  2. Effect of Sr-doping of LaMnO3 spacer on modulation-doped two-dimensional electron gases at oxide interfaces

    DEFF Research Database (Denmark)

    Chen, Yunzhong; Gan, Yulin; Christensen, Dennis Valbjørn

    2017-01-01

    Modulation-doped oxide two-dimensional electron gas formed at the LaMnO3 (LMO) buffered disorderd-LaAlO3/SrTiO3 (d-LAO/LMO/STO) heterointerface provides new opportunities for electronics as well as quantum physics. Herein, we studied the dependence of Sr-doping of La1-xSrxMnO3 (LSMO, x = 0, 1/8, ...... of LSMO during the deposition of disordered LAO or that the energy levels of Mn 3d electrons at the interface of LSMO/STO are hardly varied even when changing the LSMO composition from LMO to SrMnO3....

  3. Nutritional history does not modulate hepatic oxidative status of European sea bass (Dicentrarchus labrax) submitted to handling stress.

    Science.gov (United States)

    Castro, Carolina; Peréz-Jiménez, Amalia; Coutinho, Filipe; Corraze, Geneviève; Panserat, Stéphane; Peres, Helena; Teles, Aires Oliva; Enes, Paula

    2018-02-19

    The aim of the present study was to assess the impact of an acute handling stress on hepatic oxidative status of European sea bass (Dicentrarchus labrax) juveniles fed diets differing in lipid so urce and carbohydrate content. For that purpose, four diets were formulated with fish oil (FO) and vegetable oils (VO) as lipid source and with 20 or 0% gelatinized starch as carbohydrate source. Triplicate groups of fish with 74 g were fed each diet during 13 weeks and then subjected to an acute handling stress. Stress exposure decreased hematocrit (Ht) and hemoglobin (Hb) levels. Independent of dietary treatment, stress exposure increased hepatic lipid peroxidation (LPO). Stressed fish exhibited lower glucose 6-phosphate dehydrogenase (G6PD), catalase (CAT), and superoxide dismutase (SOD) activities, independent of previous nutritional history. In the VO groups, stress exposure increased glutathione peroxidase (GPX) activity. Diet composition had no effect on Ht and Hb levels. In contrast, dietary carbohydrate decreased hepatic LPO and CAT activity and increased glutathione reductase (GR) and G6PD activities. Dietary lipids had no effect on LPO. Fish fed the VO diets exhibited higher G6PD activity than fish fed the FO diets. In conclusion, dietary carbohydrates contributed to the reduction of oxidative stress in fish. However, under the imposed handling stress conditions, liver enzymatic antioxidant mechanisms were not enhanced, which may explain the overall increased oxidative stress.

  4. Superoxide-hydrogen peroxide genetic imbalance modulates differentially the oxidative metabolism on human peripheral blood mononuclear cells exposed to seleno-L-methionine.

    Science.gov (United States)

    Schott, Karen Lilian; Assmann, Charles Elias; Barbisan, Fernanda; Azzolin, Verônica Farina; Bonadiman, Beatriz; Duarte, Marta Maria Medeiros Frescura; Machado, Alencar Kolinski; da Cruz, Ivana Beatrice Mânica

    2017-08-01

    Superoxide-hydrogen peroxide (S-HP) imbalance genetically caused by a gene polymorphism in the human manganese superoxide dismutase enzyme (Val16Ala-MnSOD) is associated with several diseases. Into mitochondria, MnSOD catalyses superoxide radical producing HP and oxygen. Ala-MnSOD genotype presents a high MnSOD efficiency and generates the highest HP concentrations that has been associated with the risk of several cancer types. Cellular selenoenzymes glutathione peroxidase and thioredoxin reductase (TrxR) and catalase (CAT) are essential to HP removal produced in excess in cells. Since, synthesis and activities of selenoenzymes are selenium dependent, we hypothesized that AA-MnSOD cells could have an improvement on antioxidant status undergoing Seleno-L-methionine (SeMet) treatment. This study performed an in vitro protocol to evaluate the response of peripheral blood mononuclear cells (PBMC) carriers of different Val16Ala-MnSOD genotypes exposed to SeMet. SeMet effects on cell viability, apoptosis induction and modulation of oxidative variables were determined using spectrophotometric, flow cytometry, fluorimetric and immunoassays. Gene modulation of antioxidant enzymes was also performed by qRT-PCR. From an initial protocol using heterozygous (AV) cells was determined that 1nM SeMet presented a cytoprotective effect. However, whereas this concentration did not change AA viability, in VV cells it was cytotoxic by increasing necrosis events. SeMet induced higher selenoenzymes levels in AA and VV cells and decreased oxidative markers levels including DNA damage. The results suggest a pharmacogenetic positive response of SeMet effect on AA-cells. Future studies in vivo could be essential to evaluate the potential clinical impact of S-HP imbalance after use of foods or supplements containing SeMet. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Regulatory landscape of AGE-RAGE-oxidative stress axis and its modulation by PPARγ activation in high fructose diet-induced metabolic syndrome.

    Science.gov (United States)

    Cannizzaro, Luca; Rossoni, Giuseppe; Savi, Federica; Altomare, Alessandra; Marinello, Cristina; Saethang, Thammakorn; Carini, Marina; Payne, D Michael; Pisitkun, Trairak; Aldini, Giancarlo; Leelahavanichkul, Asada

    2017-01-01

    The AGE-RAGE-oxidative stress (AROS) axis is involved in the onset and progression of metabolic syndrome induced by a high-fructose diet (HFD). PPARγ activation is known to modulate metabolic syndrome; however a systems-level investigation looking at the protective effects of PPARγ activation as related to the AROS axis has not been performed. The aim of this work is to simultaneously characterize multiple molecular parameters within the AROS axis, using samples taken from different body fluids and tissues of a rat model of HFD-induced metabolic syndrome, in the presence or absence of a PPARγ agonist, Rosiglitazone (RGZ). Rats were fed with 60% HFD for the first half of the treatment duration (21 days) then continued with either HFD alone or HFD plus RGZ for the second half. Rats receiving HFD alone showed metabolic syndrome manifestations including hypertension, dyslipidemia, increased glucose levels and insulin resistance, as well as abnormal kidney and inflammatory parameters. Systolic blood pressure, plasma triglyceride and glucose levels, plasma creatinine, and albuminuria were significantly improved in the presence of RGZ. The following molecular parameters of the AROS axis were significantly upregulated in our rat model: carboxymethyl lysine (CML) in urine and liver; carboxyethyl lysine (CEL) in urine; advanced glycation end products (AGEs) in plasma; receptor for advanced glycation end products (RAGE) in liver and kidney; advanced oxidation protein products (AOPP) in plasma; and 4-hydroxynonenal (HNE) in plasma, liver, and kidney. Conversely, with RGZ administration, the upregulation of AOPP and AGEs in plasma, CML and CEL in urine, RAGE in liver as well as HNE in plasma and liver was significantly counteracted/prevented. Our data demonstrate (i) the systems-level regulatory landscape of HFD-induced metabolic syndrome involving multiple molecular parameters, including HNE, AGEs and their receptor RAGE, and (ii) attenuation of metabolic syndrome by

  6. Switching power converters medium and high power

    CERN Document Server

    Neacsu, Dorin O

    2013-01-01

    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  7. Lutein protects against β-amyloid peptide-induced oxidative stress in cerebrovascular endothelial cells through modulation of Nrf-2 and NF-κb.

    Science.gov (United States)

    Liu, Tao; Liu, Wei-Hong; Zhao, Jin-Sheng; Meng, Fan-Zheng; Wang, Heng

    2017-02-01

    In the present study, we determined the protective role of lutein against Aβ 25-35 peptide-induced oxidative stress and apoptosis in bEND.3 cells. Cell viability was determined through MTT assay. Reactive oxygen species, lipid peroxides, and antioxidant enzyme activities were evaluated to analyze the oxidative stress status. NF-κB and Nrf-2 downstream target protein expressions were determined through western blot. Apoptosis was analyzed through caspase activities and subG1 accumulation. The results showed that Aβ 25-35 significantly increased (p Lutein pre-treatment significantly (p Lutein prevented Aβ 25-35 -induced NF-κB nuclear expressions and up-regulated Nrf-2 expressions. Further, lutein also improved mitochondrial membrane potential and down-regulated caspase activities and subG1 accumulation. The present study shows the protective role of lutein against Aβ 25-35 -induced toxicity by modulating Nrf-2 and NF-κB expressions in cerebrovascular endothelial cells.

  8. Antidiabetic activities of polysaccharides separated from Inonotus obliquus via the modulation of oxidative stress in mice with streptozotocin-induced diabetes.

    Science.gov (United States)

    Wang, Juan; Hu, Wenji; Li, Lanzhou; Huang, Xinping; Liu, Yange; Wang, Di; Teng, Lirong

    2017-01-01

    This study evaluated the effects of Inonotus obliquus polysaccharides (IOs) on diabetes and other underlying mechanisms related to inflammatory factors and oxidative stress in a mouse model of streptozotocin (STZ)-induced diabetes. Four weeks administration of metformin (120 mg/kg) and IO1-4 (50%-80% alcohol precipitation), or IO5 (total 80% alcohol precipitation) at doses of 50 mg/kg reverses the abnormal changes of bodyweights and fasting blood glucose levels of diabetic mice. IOs significantly increased the insulin and pyruvate kinase levels in serum, and improved the synthesis of glycogen, especially for IO5. IOs restored the disturbed serum levels of superoxide dismutase, catalase, glutathione peroxidase, and malondialdehyde. The down-regulation of interleukin-2 receptor, matrix metalloproteinase-9, and the enhancement of interleukin-2 in serum of diabetic mice were significantly attenuated by IOs. Histologic and morphology examinations showed that IOs repaired the damage on kidney tissues, inhibited inflammatory infiltrate and extracellular matrix deposit injuries in diabetic mice. Compared with untreated diabetic mice, IOs decreased the expression of phosphor-NF-κB in the kidneys. These results show that IOs treatment attenuated diabetic and renal injure in STZ-induced diabetic mice, possibly through the modulation of oxidative stress and inflammatory factors. These results provide valuable evidences to support the use of I. obliquus as a hypoglycemic functional food and/or medicine.

  9. Vanillin abrogates ethanol induced gastric injury in rats via modulation of gastric secretion, oxidative stress and inflammation

    Directory of Open Access Journals (Sweden)

    Abdulrahman Al Asmari

    Full Text Available Vanillin is commonly used as an additive in food, medicine and cosmetics, but its effect has not yet been studied in gastric injury. Therefore the effect of vanillin was studied in experimental gastric ulcer. Gastric secretion and acidity were studied in pylorus ligated rats. Ulcer index, levels of gastric mucus, malondialdehyde (MDA, myeloperoxidase activity (MPO, expression of nuclear factor kappa B (NF-κB p65, and histopathological changes were determined in ethanol induced gastric ulcer. Pre treatment with vanillin significantly reduced gastric secretion (P < 0.001 and acidity (P < 0.0001 and gastric ulcer index scores (P < 0.001. and augmented the gastric mucosal defense. Vanillin significantly restored the depleted gastric wall mucus levels (P < 0.0001 induced by ethanol and also significantly attenuated ethanol induced inflammation and oxidative stress by the suppression of gastric MPO activity (P < 0.001, reducing the expression of NF-κB p65 and the increased MDA levels (P < 0.001. Vanillin was also effective in alleviating the damage to the histological architecture and the activation of mast cells induced by ethanol.Together the results of this study highlight the gastroprotective activity of vanillin in gastric ulcers of rats through multiple actions that include inhibition of gastric secretion and acidity, reduction of inflammation and oxidative stress, suppression of expression of NF-κB, and restoration of the histological architecture. Keywords: Gastric ulcers, Pylorus ligation, Ethanol, Vanillin, Inflammation, Oxidative stress

  10. Sweet potato Ipomoea Batatas Modulates Radiation-induced Oxidative damage in Liver and kidney of Male Albino Rats

    International Nuclear Information System (INIS)

    Darwish, M. M.; Farag, M. F. S.; Osman, N. N.

    2010-01-01

    Sweet potato Ipomoea Batatas, one of the major vegetable crops consumed worldwide, is rich in phytochemicals, which displayed antioxidant activities. This work aims at assessing the radio-protective properties of sweet potato tubers on liver and kidney tissues. Male albino rats were whole body exposed to 0.5 Gy day after day for a period of 20 days. Animal received orally prepared aqueous extract of sweet potato tubers (100 mg kg/body weight), one week before irradiation and during the period of radiation exposure. The results demonstrated that irradiation of rats induced a significant increase in lipid peroxides level measured as thiobarbituric acid reactive substances (TBARS) concomitant with a significant decrease in superoxide dismutase (SOD), and catalase (CAT) activity and glutathione (GSH) content in liver and kidney tissues. Administration of a freshly prepared aqueous extract of sweet potato tubers to rats, one week pre-irradiation and during the period of radiation exposure has significantly of ameliorated the oxidative stress in both tissues. The significant amelioration in oxidative stress was substantiated by improvement of liver and kidney enzymes Treatment of rats with sweet potato has significantly reduced the increase in serum alanine amino transferase (ALT), aspartate amino transferase (AST) and lactate dehydrogenase (LDH) activity, serum creatinine and urea levels. Furthermore, hyperglycemia and alteration in lipid profile manifested by a significant increase in triglycerides (TG), total cholesterol (TC), and low density lipoprotein cholesterol (LDL-C), and a significant decrease in high density lipoprotein cholesterol (HDL-C), were improved in sweet potato-treated irradiated rats compared to those only irradiated. According to the results obtained in the present study, it could be concluded that sweet potato through its antioxidant activities could protect cellular membrane from radiation induced oxidative damage in animals and preserve the

  11. Oxidative stress modulates heme synthesis and induces peroxiredoxin-2 as a novel cytoprotective response in β-thalassemic erythropoiesis.

    Science.gov (United States)

    De Franceschi, Lucia; Bertoldi, Mariarita; De Falco, Luigia; Santos Franco, Sara; Ronzoni, Luisa; Turrini, Franco; Colancecco, Alessandra; Camaschella, Clara; Cappellini, Maria Domenica; Iolascon, Achille

    2011-11-01

    β-thalassemic syndromes are inherited red cell disorders characterized by severe ineffective erythropoiesis and increased levels of reactive oxygen species whose contribution to β-thalassemic anemia is only partially understood. We studied erythroid precursors from normal and β-thalassemic peripheral CD34(+) cells in two-phase liquid culture by proteomic, reverse transcriptase polymerase chain reaction and immunoblot analyses. We measured intracellular reactive oxygen species, heme levels and the activity of δ-aminolevulinate-synthase-2. We exposed normal cells and K562 cells with silenced peroxiredoxin-2 to H(2)O(2) and generated a recombinant peroxiredoxin-2 for kinetic measurements in the presence of H(2)O(2) or hemin. In β-thalassemia the increased production of reactive oxygen species was associated with down-regulation of heme oxygenase-1 and biliverdin reductase and up-regulation of peroxiredoxin-2. In agreement with these observations in β-thalassemic cells we found decreased heme levels related to significantly reduced activity of the first enzyme of the heme pathway, δ-aminolevulinate synthase-2 without differences in its expression. We demonstrated that the activity of recombinant δ-aminolevulinate synthase-2 is inhibited by both reactive oxygen species and hemin as a protective mechanism in β-thalassemic cells. We then addressed the question of the protective role of peroxiredoxin-2 in erythropoiesis by exposing normal cells to oxidative stress and silencing peroxiredoxin-2 in human erythroleukemia K562 cells. We found that peroxiredoxin-2 expression is up-regulated in response to oxidative stress and required for K562 cells to survive oxidative stress. We then showed that peroxiredoxin-2 binds heme in erythroid precursors with high affinity, suggesting a possible multifunctional cytoprotective role of peroxiredoxin-2 in β-thalassemia. In β-thalassemic erythroid cells the reduction of δ-aminolevulinate synthase-2 activity and the increased

  12. Putrescine reduces antibiotic-induced oxidative stress as a mechanism of modulation of antibiotic resistance in Burkholderia cenocepacia.

    Science.gov (United States)

    El-Halfawy, Omar M; Valvano, Miguel A

    2014-07-01

    Communication of antibiotic resistance among bacteria via small molecules is implicated in transient reduction of bacterial susceptibility to antibiotics, which could lead to therapeutic failures aggravating the problem of antibiotic resistance. Released putrescine from the extremely antibiotic-resistant bacterium Burkholderia cenocepacia protects less-resistant cells from different species against the antimicrobial peptide polymyxin B (PmB). Exposure of B. cenocepacia to sublethal concentrations of PmB and other bactericidal antibiotics induces reactive oxygen species (ROS) production and expression of the oxidative stress response regulator OxyR. We evaluated whether putrescine alleviates antibiotic-induced oxidative stress. The accumulation of intracellular ROS, such as superoxide ion and hydrogen peroxide, was assessed fluorometrically with dichlorofluorescein diacetate, while the expression of OxyR and putrescine synthesis enzymes was determined in luciferase assays using chromosomal promoter-lux reporter system fusions. We evaluated wild-type and isogenic deletion mutant strains with defects in putrescine biosynthesis after exposure to sublethal concentrations of PmB and other bactericidal antibiotics. Exogenous putrescine protected against oxidative stress induced by PmB and other antibiotics, whereas reduced putrescine synthesis resulted in increased ROS generation and a parallel increased sensitivity to PmB. Of the 3 B. cenocepacia putrescine-synthesizing enzymes, PmB induced only BCAL2641, an ornithine decarboxylase. This study reveals BCAL2641 as a critical component of the putrescine-mediated communication of antibiotic resistance and as a plausible target for designing inhibitors that would block the communication of such resistance among different bacteria, ultimately reducing the window of therapeutic failure in treating bacterial infections. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  13. Modulation of surface structure and catalytic properties of cerium oxide nanoparticles by thermal and microwave synthesis techniques

    Energy Technology Data Exchange (ETDEWEB)

    He, Jian [College of Pharmacy, Third Military Medical University, Chongqing 400038 (China); Zhou, Lan; Liu, Jie; Yang, Lu; Zou, Ling; Xiang, Junyu; Dong, Shiwu [School of Biomedical Engineering, Third Military Medical University, Chongqing 400038 (China); Yang, Xiaochao, E-mail: xcyang@tmmu.edu.cn [School of Biomedical Engineering, Third Military Medical University, Chongqing 400038 (China)

    2017-04-30

    Highlights: • The CNPs synthesized by microwave irradiation have more reactive hot spots than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation exhibited higher SOD activity than that synthesized by convective heating. • The CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress. - Abstract: Cerium oxide nanoparticles (CNPs) have been intensively explored for biomedical applications in recent few years due to the versatile enzyme mimetic activities of the nanoparticles. However, the control of CNPs quality through the optimization of synthesis conditions remains largely unexplored as most of the previous studies only focus on utilizing the catalytic activities of the nanoparticles. In the present study, CNPs with size about 5 nm were synthesized by thermal decomposition method using traditional convective heating and recently developed microwave irradiation as heating source. The quality of CNPs synthesized by the two heating manner was evaluated. The CNPs synthesized by convective heating were slightly smaller than that synthesized by microwave irradiation heating. The cores of the CNPs synthesized by the two heating manner have similar crystal structure. While the surface subtle structures of the CNPs synthesized by two heating manner were different. The CNPs synthesized by microwave irradiation have more surface reactive hot spot than that synthesized by convective heating as the nanoparticles responded more actively to the redox environment variation. This difference resulted in the higher superoxide dismutase (SOD) mimetic activity of CNPs synthesized by microwave irradiation heating than that of the convective heating. Preliminary experiments indicated that the CNPs synthesized by microwave irradiation heating could better protect cells from oxidative stress due to the higher SOD mimetic activity of the nanoparticles.

  14. Nitric oxide modulation of the basal ganglia circuitry: therapeutic implication for Parkinson's disease and other motor disorders.

    Science.gov (United States)

    Pierucci, Massimo; Galati, Salvatore; Valentino, Mario; Di Matteo, Vincenzo; Benigno, Arcangelo; Pitruzzella, Alessandro; Muscat, Richard; Di Giovanni, Giuseppe

    2011-11-01

    Several recent studies have emphasized a crucial role for the nitrergic system in movement control and the pathophysiology of the basal ganglia (BG). These observations are supported by anatomical evidence demonstrating the presence of nitric oxide synthase (NOS) in all the basal ganglia nuclei. In fact, nitrergic terminals have been reported to make synaptic contacts with both substantia nigra dopamine-containing neurons and their terminal areas such as the striatum, the globus pallidus and the subthalamus. These brain areas contain a high expression of nitric oxide (NO)-producing neurons, with the striatum having the greatest number, together with important NO afferent input. In this paper, the distribution of NO in the BG nuclei will be described. Furthermore, evidence demonstrating the nitrergic control of BG activity will be reviewed. The new avenues that the increasing knowledge of NO in motor control has opened for exploring the pathophysiology and pharmacology of Parkinson's disease and other movement disorders will be discussed. For example, inhibition of striatal NO/guanosine monophosphate signal pathway by phosphodiesterases seems to be effective in levodopa-induced dyskinesia. However, the results of experimental studies have to be interpreted with caution given the complexities of nitrergic signalling and the limitations of animal models. Nevertheless, the NO system represents a promising pharmacological intervention for treating Parkinson's disease and related disorders.

  15. Investigation of the effects of Chlorella vulgaris supplementation on the modulation of oxidative stress in apparently healthy smokers.

    Science.gov (United States)

    Panahi, Yunes; Mostafazadeh, Babak; Abrishami, Alireza; Saadat, Alireza; Beiraghdar, Fatemeh; Tavana, Sasan; Pishgoo, Bahram; Parvin, Shahram; Sahebkar, Amirhossein

    2013-01-01

    Smoking is among the established yet modifiable risk factors for cancers, cardiovascular diseases, and pulmonary disorders. Oxidative stress has been proposed as a key mechanism mediating the deleterious consequences of smoking. The present study evaluated the effect of supplementation with Chlorella vulgaris, a nutrient and bioactive green microalgae with proven antioxidant capacity, on the burden of oxidative stress in Iranian smokers. Thirty-eight smokers (mean age: 37.11 +/- 1.69 years; females: 18.4%) were administered C. vulgaris extract (3600 mg/day) for a period of 6 weeks. Fasted serum samples collected at baseline and after the completion of study were analyzed for the concentrations of vitamin C, vitamin E, glutathione, and malonedialdehyde (MDA) as well as activities of superoxide dismutase, glutathione peroxidase, and catalase. Total antioxidant capacity of serum was also determined by the ability of serum to inhibit the formation of ferryl myoglobin radical species. Six-week supplementation with C. vulgaris extract in smokers was associated with marked elevation of all assessed serum antioxidant measures (p lack of significant change in serum vitamin E status in females. Although the magnitude of change in serum vitamin E was significantly greater in males compared to females (p = 0.014), there was no significant change in the magnitude of changes for other assessed parameters between the genders. Supplementation with C. vulgaris extract significantly improves antioxidant status and attenuates lipid peroxidation in chronic cigarette smokers. Hence, C. vulgaris might prevent the disease burden and mortality rate associated with smoking.

  16. Modulation of oxidative and inflammatory cardiac response by nonselective 1- and 2-cyclooxygenase inhibitor and benznidazole in mice.

    Science.gov (United States)

    Santos, Eliziária C; Novaes, Rômulo D; Bastos, Daniel S S; Oliveira, Jerusa M; Penitente, Arlete R; Gonçalves, Wagner G; Cardoso, Silvia A; Talvani, André; Oliveira, Leandro L

    2015-11-01

    This study investigated the combined effects of benznidazole (BZ) and ibuprofen (IB) on the oxidative and inflammatory status of the cardiac tissue in vivo. Swiss mice were randomized in groups receiving BZ (100 mg/kg) and IB (400 mg/kg) alone or combined (BZ + IB 200 or 400 mg/kg). Control animals were concurrently treated with 1% carboxymethyl cellulose. All treatments were administered orally for 7 days. BZ treatment increased cardiac production of nitrogen/oxygen-reactive species, malondialdeyde, carbonyl proteins, prostaglandins as well as the activities of catalase, superoxide dismutase and glutathione peroxidase. These parameters were attenuated by IB, with the best results at higher dose. Individually, BZ and IB significantly reduced the tissue levels of chemokine ligand 2, tumour necrosis factor-α and IL-10, but no reduction was observed when the treatments were combined. BZ triggers an oxidative and nitrosative route, which is associated with increased prostaglandin synthesis and marked damages to the lipids and proteins of the cardiac tissue. IB treatment attenuated reactive stresses triggered by BZ, which was an independent effects of this drug on the endogenous antioxidant enzymes. Individually, but not together, BZ and IB reduced the cardiac inflammatory status, indicating a beneficial and complex drug interaction. © 2015 Royal Pharmaceutical Society.

  17. Dietary Saccharomyces cerevisiae Cell Wall Extract Supplementation Alleviates Oxidative Stress and Modulates Serum Amino Acids Profiles in Weaned Piglets

    Directory of Open Access Journals (Sweden)

    Gang Liu

    2017-01-01

    Full Text Available This research aims to evaluate the effects of dietary supplementation with Saccharomyces cerevisiae cell wall extract (SCCWE on growth performance, oxidative stress, intestinal morphology, and serum amino acid concentration in weaned piglets. Utilizing a completely randomized design, 40 healthy piglets weaned at 21 d were grouped into 4 experimental treatments with 10 pigs per treatment group. Treatments consisted of a basal diet (T0, a basal diet with a 0.05% SCCWE (T1, a basal diet with a 0.10% SCCWE (T2, and a basal diet with a 0.15% SCCWE (T3. SCCWE supplementation increased the average daily gain and final body weight compared with T0 (P<0.05. SCCWE in T2 and T3 improved the average daily feed intake and decreased the feed/gain ratio compared with T1 and T2 (P<0.05. SCCWE decreased serum malondialdehyde (MDA and increased activities of catalase (CAT, glutathione peroxidase (GPx, and superoxide dismutase (SOD significantly compared to T0 (P<0.05. SCCWE increased the concentration of Ile compared to T0 (P<0.05. Moreover, the concentrations of Leu, Phe, and Arg were higher in T2 and T3 (P<0.05. These findings indicate beneficial effects of SCCWE supplementation on growth performance, the concentration of some essential amino acids, and alleviation of oxidative stress in weaned piglets.

  18. Redox signaling via oxidative inactivation of PTEN modulates pressure-dependent myogenic tone in rat middle cerebral arteries.

    Directory of Open Access Journals (Sweden)

    Debebe Gebremedhin

    Full Text Available The present study examined the level of generation of reactive oxygen species (ROS and roles of inactivation of the phosphatase PTEN and the PI3K/Akt signaling pathway in response to an increase in intramural pressure-induced myogenic cerebral arterial constriction. Step increases in intraluminal pressure of cannulated cerebral arteries induced myogenic constriction and concomitant formation of superoxide (O2 (.- and its dismutation product hydrogen peroxide (H2O2 as determined by fluorescent HPLC analysis, microscopic analysis of intensity of dihydroethidium fluorescence and attenuation of pressure-induced myogenic constriction by pretreatment with the ROS scavenger 4,hydroxyl-2,2,6,6-tetramethylpiperidine1-oxyl (tempol or Mito-tempol or MitoQ in the presence or absence of PEG-catalase. An increase in intraluminal pressure induced oxidation of PTEN and activation of Akt. Pharmacological inhibition of endogenous PTEN activity potentiated pressure-dependent myogenic constriction and caused a reduction in NPo of a 238 pS arterial KCa channel current and an increase in [Ca(2+]i level in freshly isolated cerebral arterial muscle cells (CAMCs, responses that were attenuated by Inhibition of the PI3K/Akt pathway. These findings demonstrate an increase in intraluminal pressure induced increase in ROS production triggered redox-sensitive signaling mechanism emanating from the cross-talk between oxidative inactivation of PTEN and activation of the PI3K/Akt signaling pathway that involves in the regulation of pressure-dependent myogenic cerebral arterial constriction.

  19. Nitric oxide and hydrogen peroxide in tomato resistance. Nitric oxide modulates hydrogen peroxide level in o-hydroxyethylorutin-induced resistance to Botrytis cinerea in tomato.

    Science.gov (United States)

    Małolepsza, Urszula; Rózalska, Sylwia

    2005-06-01

    Nitric oxide (NO) has been postulated to be required, together with reactive oxygen species (ROS), for activation of disease resistance reactions of plants to infection with a pathogen or elicitor treatment. However, biochemical mechanisms by which ROS and NO participate in these reactions are still under intensive study and controversial debate. We previously demonstrated that o-hydroxyethylorutin when applied on tomato leaves (Lycopersicon esculentum Mill. cv. "Perkoz") restricted Botrytis cinerea infection development. In this research we investigated ROS and NO generation in tomato plants treated with o-hydroxyethylorutin, non-treated and infected ones. The NO content was enhanced or decreased in the studied plants by supplying them with NO generator-SNP or scavenger-cPTIO. NO detection was carried out using diaminofluorescein diacetate (DAF-DA) in conjunction with confocal laser scanning microscopy. The influence of elevated and decreased levels of NO on B. cinerea infection development and ROS generation was studied. The elevated NO concentration in tomato leaves strongly decreased hydrogen peroxide concentration without affecting other studied ROS (superoxide anion and hydroxyl radical) levels. H2O2 concentrations in NO-supplied leaves were low regardless of further treatment of tomato leaves with o-hydroxyethylorutin or inoculation with B. cinerea. The low H2O2 concentration coincided with quick and severe infection development in NO-supplied leaves. As activities of enzymes generating (SOD EC 1.15.1.1)) and removing (APX EC 1.11.1.11, CAT EC 1.11.1.6) H2O2 were unchanged in the studied plants, the decrease in H2O2 concentration was probably due to a direct NO-H2O2 interaction.

  20. Anthocyanin – Rich Red Dye of Hibiscus Sabdariffa Calyx Modulates Cisplatin-induced Nephrotoxicity and Oxidative Stress in Rats

    Science.gov (United States)

    Ademiluyi, Adedayo O.; Oboh, Ganiyu; Agbebi, Oluwaseun J.; Akinyemi, Ayodele J.

    2013-01-01

    This study sought to investigate the protective effect of dietary inclusion of Hibiscus sabdariffa calyx red dye on cisplatin-induced nephrotoxicity and antioxidant status in rats. Adult male rats were randomly divided into four groups of six animals each. Groups I and II were fed basal diet while groups III and IV were fed diets containing 0.5% and 1% of the dye respectively for 20 days prior to cisplatin administration. Nephrotoxicity was induced by a single dose intraperitoneal administration of cisplatin (7 mg/kg b.w) and the experiment was terminated 3 days after. The kidney and plasma were studied for nephrotoxicity and oxidative stress indices. Cisplatin administration caused a significant (Psabdariffa dye could be attributed to its anthocyanin content. PMID:24711761

  1. Modulation of inducible nitric oxide synthase gene expression in RAW 264.7 murine macrophages by Pacific ciguatoxin.

    Science.gov (United States)

    Kumar-Roiné, Shilpa; Matsui, Mariko; Chinain, Mireille; Laurent, Dominique; Pauillac, Serge

    2008-08-01

    To investigate the possible involvement of the nitric oxide radical (NO) in ciguatera fish poisoning (CFP), the in vitro effects of the main Pacific ciguatoxin (P-CTX-1B) and bacterial lipopolysaccharide (LPS) were comparatively studied on neuroblastoma Neuro-2a and on macrophage RAW 264.7 cell lines. NO accumulation was quantified by measuring nitrite levels in cellular supernatant using Griess reagent while the up-regulation of inducible nitric oxide synthase (iNOS) at the mRNA level was quantified via Real-Time Reverse-Transcription Polymerase Chain Reaction (RT-PCR). P-CTX-1B caused a concentration- and time-dependent induction of iNOS in RAW 264.7 cells but not in Neuro-2a cells. NO production was evidenced by increased nitrite levels in the 10 microM range after 48 h of RAW 264.7 cells exposure to LPS and P-CTX-1B (0.05 microg/ml and 6 nM, respectively). The expression of iNOS mRNA peaked at 8h for LPS then gradually decreased to low level at 48 h. In contrast, a sustained level was recorded with P-CTX-1B in the 8-48 h time interval. The addition of N(omega)-nitro-L-arginine methyl ester (L-NAME), a stereoselective NOS inhibitor, strongly diminished NO formation but had no effect on iNOS mRNA synthesis. The implication of NO in CFP paves the way for new therapies for both western and traditional medicines.

  2. Hypoxic transcription gene profiles under the modulation of nitric oxide in nuclear run on-microarray and proteomics

    Directory of Open Access Journals (Sweden)

    Dehne Nathalie

    2009-09-01

    Full Text Available Abstract Background Microarray analysis still is a powerful tool to identify new components of the transcriptosome. It helps to increase the knowledge of targets triggered by stress conditions such as hypoxia and nitric oxide. However, analysis of transcriptional regulatory events remain elusive due to the contribution of altered mRNA stability to gene expression patterns as well as changes in the half-life of mRNAs, which influence mRNA expression levels and their turn over rates. To circumvent these problems, we have focused on the analysis of newly transcribed (nascent mRNAs by nuclear run on (NRO, followed by microarray analysis. Results We identified 196 genes that were significantly regulated by hypoxia, 85 genes affected by nitric oxide and 292 genes induced by the cotreatment of macrophages with both NO and hypoxia. Fourteen genes (Bnip3, Ddit4, Vegfa, Trib3, Atf3, Cdkn1a, Scd1, D4Ertd765e, Sesn2, Son, Nnt, Lst1, Hps6 and Fxyd5 were common to all treatments but with different levels of expression in each group. We observed that 162 transcripts were regulated only when cells were co-treated with hypoxia and NO but not with either treatment alone, pointing to the importance of a crosstalk between hypoxia and NO. In addition, both array and proteomics data supported a consistent repression of hypoxia-regulated targets by NO. Conclusion By eliminating the interference of steady state mRNA in gene expression profiling, we obtained a smaller number of significantly regulated transcripts in our study compared to published microarray data and identified previously unknown hypoxia-induced targets. Gene analysis profiling corroborated the interplay between NO- and hypoxia-induced signaling.

  3. Solanum torvum Swartz. fruit attenuates cadmium-induced liver and kidney damage through modulation of oxidative stress and glycosylation.

    Science.gov (United States)

    Ramamurthy, C H; Subastri, A; Suyavaran, A; Subbaiah, K C V; Valluru, L; Thirunavukkarasu, C

    2016-04-01

    Increased levels of environmental pollutants are linked to almost all human disorders; the efficient method to manage the human health is through naturally available dietary molecule. Solanum torvum (ST) Swartz (Solanaceae) commonly called Turkey Berry is found in Africa, Asia, and South America. Its fruit, part of traditional Indian cuisine, is a widely consumed nutritious herb, acclaimed for its medicinal value. ST aqueous extract (STAe) (250, 500, and 1000 mg/kg b.w., 6 days; oral) against acute Cadmium (Cd) (6.3 mg/kg b.w., single dose; oral) toxicity was evaluated in rats. Protective effect was assessed using serum markers, tissue antioxidants, oxidant derivatives, glycoprotein, and histopathological studies. The activities of serum marker enzymes were increased (40-60 %); antioxidant enzymes such as SOD and CAT, GSH, and its metabolic enzyme activities were decreased (50-80 %) in the liver and kidney upon Cd intoxication. During STAe pre-treatment, at doses of 250 and 500 mg/kg b.w., the above changes were brought to near normal (25-63 %). Tissue 4-hydroxynonenal, 3-nitrotyrosine, and protein carbonyls were increased (8-15 fold) in Cd-alone-treated rats, whereas pre-supplementation of STAe significantly decreased their levels and inhibited the protein glycosylation effectively. The pharmacological effect of STAe was confirmed by histopathological observations. Based on previous literature and present investigation, we conclude that ST may serve as a potential functional food against environmental contaminant such as heavy metal-induced oxidative stress.

  4. Organic vapor discrimination with chemiresistor arrays of temperature modulated tin-oxide nanowires and thiolate-monolayer-protected gold nanoparticles

    Science.gov (United States)

    Scholten, K.; Bohrer, F. I.; Dattoli, E.; Lu, W.; Zellers, E. T.

    2011-03-01

    This paper explores the discrimination of organic vapors with arrays of chemiresistors (CRs) employing interface layers of tin-oxide nanowires (NWs) and thiolate-monolayer-protected gold nanoparticles (MPNs). The former devices use contact-printed mats of NWs on micro-hotplate membranes to bridge a pair of metal electrodes. Oxidation at the NW surface causes changes in charge transport, the temperature dependence of which differs among different vapors, permitting vapor discrimination. The latter devices use solvent cast films of MPNs on interdigital electrodes operated at room temperature. Sorption into the organic monolayers causes changes in film tunneling resistance that differ among different vapors and MPN structures, permitting vapor discrimination. Here, we compare the performance and assess the 'complementarity' of these two types of sensors. Calibrated responses from an NW CR operated at two different temperatures and from a set of four different MPN CRs were generated for three test vapors: n-hexane, toluene, and nitromethane. This pooled data set was then analyzed using principal components regression classification models with varying degrees of random error superimposed on the responses via Monte Carlo simulation in order to estimate the rates of recognition/discrimination for arrays comprising different combinations of sensors. Results indicate that the diversity of most of the dual MPN-CR arrays exceeds that of the dual NW-CR array. Additionally, in assessing all possible arrays of 4-6 CR sensors, the recognition rates of the hybrid arrays (i.e. MPN + NW) were no better than that of the 4-sensor array containing only MPN CRs.

  5. Physical Forces Modulate Oxidative Status and Stress Defense Meditated Metabolic Adaptation of Yeast Colonies: Spaceflight and Microgravity Simulations

    Science.gov (United States)

    Hammond, Timothy G.; Allen, Patricia L.; Gunter, Margaret A.; Chiang, Jennifer; Giaever, Guri; Nislow, Corey; Birdsall, Holly H.

    2017-12-01

    Baker's yeast (Saccharomyces cerevisiae) has broad genetic homology to human cells. Although typically grown as 1-2mm diameter colonies under certain conditions yeast can form very large (10 + mm in diameter) or `giant' colonies on agar. Giant yeast colonies have been used to study diverse biomedical processes such as cell survival, aging, and the response to cancer pharmacogenomics. Such colonies evolve dynamically into complex stratified structures that respond differentially to environmental cues. Ammonia production, gravity driven ammonia convection, and shear defense responses are key differentiation signals for cell death and reactive oxygen system pathways in these colonies. The response to these signals can be modulated by experimental interventions such as agar composition, gene deletion and application of pharmaceuticals. In this study we used physical factors including colony rotation and microgravity to modify ammonia convection and shear stress as environmental cues and observed differences in the responses of both ammonia dependent and stress response dependent pathways We found that the effects of random positioning are distinct from rotation. Furthermore, both true and simulated microgravity exacerbated both cellular redox responses and apoptosis. These changes were largely shear-response dependent but each model had a unique response signature as measured by shear stress genes and the promoter set which regulates them These physical techniques permitted a graded manipulation of both convection and ammonia signaling and are primed to substantially contribute to our understanding of the mechanisms of drug action, cell aging, and colony differentiation.

  6. Administration of Curcumin Protects Kidney Tubules Against Renal Ischemia-Reperfusion Injury (RIRI) by Modulating Nitric Oxide (NO) Signaling Pathway.

    Science.gov (United States)

    Liu, Fuhe; Ni, Wenjuan; Zhang, Jiajia; Wang, Guokang; Li, Fanzhu; Ren, Wenxia

    2017-01-01

    To explore the protective effect of curcumin on renal ischemia-reperfusion injury (RIRI) in rats, and its influence on nephridial tissue's NO and cGMP levels as well as downstream signaling pathway, to elucidate the possible mechanism of curcumin on RIRI. 36 Sprague Dawley rats (SD rats) were randomly divided into Sham group, Model group, curcumin (CUR +) Model group, 12 rats per group. They were all given RIRI model preparation by unilateral artery occlusion method. All groups' β2-MG in urine in 24h, serum Cr and BUN were compared, and UAER were calculated. Nitric oxide synthase (NOS), cGMP-dependent protein kinase (PKG), Caspase-3 expression were all determined by western blot. Nitric oxide (NO), NOS and cGMP levels were also examined by using ELISA. All groups' nephridial histomorphology and kidney tubules score were evaluated and compared. β2-MG and UAER in urine, serum Cr and BUN, in renal tissue were all elevated in Model of RIRI, indicating the success of animal model of RIRI establishment, and above index in CUR + Model group were all lower than those in Model group. Furthermore, iNOS, NO, cGMP, PKG and Caspase-3 in renal tissue were all increased in Model of RIRI, indicating the NO signaling pathway was activated, which is one of the pathogenesis of RIRI, and above index in CUR + Model group were all lower than those in Model group, suggesting that inactivation of iNOS/NO/cGMP/PKG signaling pathway is one of the reasons that explain the protective effect of curcumin in RIRI. The activation of iNOS/NO/cGMP/PKG signaling pathway and the consequent promoted apoptosis of renal tubules are significantly involved in the pathogenesis of development of RIRI, and curcumin treatment could protect renal tubules against RIRI, at least partially, by suppressing the activated iNOS/NO/cGMP/PKG signaling pathway. © 2017 The Author(s). Published by S. Karger AG, Basel.

  7. Attenuation of collagen induced arthritis by Centella asiatica methanol fraction via modulation of cytokines and oxidative stress.

    Science.gov (United States)

    Sharma, Shikha; Gupta, Ritu; Thakur, Sonu Chand

    2014-12-01

    To investigate the anti-inflammatory, antioxidant and anti-arthritic effects of Centella asiatica methanolfraction (CaME) on collagen-induced arthritis (CIA), an animal model of rheumatoid arthritis. Arthritis was induced in female wistar rats by immunization with porcine type II collagen. The CIA rats were treated orally with CaME (50, 150, and 250 mg/kg/day) for 15 d (beginning on day 21 of the experimental period). The clinical, histological, biochemical, and immunological parameters were assessed. CaME treatment (150 and 250 mg/kg) significantly attenuated the severity of CIA and reduced the synovial inflammation, cartilage erosion, and bone erosion as evident from both histological and radiographic data. The escalated plasma levels of pro-inflammatory cytokines TNF-α, IL-1β, IL-6, and IL-12 alongwith nitric oxide in CIA rats decreased significantly on CaME treatment. The serum levels of type-II collagen antibody were significantly lower in rats of CaME (150 and 250 mg/kg) treated group than those in the arthritic group. Furthermore, by inhibiting the above mediators, CaME also contributed towards the reversal of the disturbed antioxidant levels and peroxidative damage. Our results clearly indicate that oral administration of CaME suppresses joint inflammation, cytokine expression as well as antioxidant imbalance, thereby contributing to an amelioration of arthritis severity in CIA rats. Copyright © 2014 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  8. Vanillin abrogates ethanol induced gastric injury in rats via modulation of gastric secretion, oxidative stress and inflammation.

    Science.gov (United States)

    Al Asmari, Abdulrahman; Al Shahrani, Hamoud; Al Masri, Nasser; Al Faraidi, Ahmed; Elfaki, Ibrahim; Arshaduddin, Mohammed

    2016-01-01

    Vanillin is commonly used as an additive in food, medicine and cosmetics, but its effect has not yet been studied in gastric injury. Therefore the effect of vanillin was studied in experimental gastric ulcer. Gastric secretion and acidity were studied in pylorus ligated rats. Ulcer index, levels of gastric mucus, malondialdehyde (MDA), myeloperoxidase activity (MPO), expression of nuclear factor kappa B (NF-κB) p65, and histopathological changes were determined in ethanol induced gastric ulcer. Pre treatment with vanillin significantly reduced gastric secretion ( P  Vanillin significantly restored the depleted gastric wall mucus levels ( P  Vanillin was also effective in alleviating the damage to the histological architecture and the activation of mast cells induced by ethanol. Together the results of this study highlight the gastroprotective activity of vanillin in gastric ulcers of rats through multiple actions that include inhibition of gastric secretion and acidity, reduction of inflammation and oxidative stress, suppression of expression of NF-κB, and restoration of the histological architecture.

  9. Caffeine-supplemented diet modulates oxidative stress markers and improves locomotor behavior in the lobster cockroach Nauphoeta cinerea.

    Science.gov (United States)

    da Silva, Cícera Simoni; de Cássia Gonçalves de Lima, Rita; Elekofehinti, Olusola Olalekan; Ogunbolude, Yetunde; Duarte, Antonia Eliene; Rocha, João Batista Teixeira; Alencar de Menezes, Irwin Rose; Barros, Luiz Marivando; Tsopmo, Appolinaire; Lukong, Kiven Erique; Kamdem, Jean Paul

    2018-02-25

    The effects of caffeine supplementation is well documented in conventional animal models, however, in the lobster cockroaches Nauphoeta cinerea, they have not been reported. Thus, the aim of this study was to investigate the locomotor behavior and biochemical endpoints in the head of the nymphs of N. cinerea following 60 days exposure to food supplemented with 0, 0.5, 1.0, 2.5, 5.0 and 10.0 mg of caffeine/g of diet. The analysis of the locomotor behavior using the video-tracking software, Any-maze, for 12 min revealed that caffeine supplementation caused significant behavioral improvement. There was increase in distance travelled, velocity, frequency of rotation and turn angle (stereotypical behavior such as circling movements), and this was supported by the representative track plots of the path travelled by cockroaches in the open-field arena. In addition, caffeine supplementation markedly increased total thiol and non-protein thiol glutathione (GSH) levels in the heads of cockroaches, and this was in parallel with significant reduction of lipid peroxidation and free Fe(II) content. Taking together, our results indicate that long-term caffeine supplementation may exert preventive effects against oxidative stress and support the use of N. cinerea as an efficient alternative model to assess the efficacy of food molecules. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Natural thioallyl compounds increase oxidative stress resistance and lifespan in Caenorhabditis elegans by modulating SKN-1/Nrf.

    Science.gov (United States)

    Ogawa, Takahiro; Kodera, Yukihiro; Hirata, Dai; Blackwell, T Keith; Mizunuma, Masaki

    2016-02-22

    Identification of biologically active natural compounds that promote health and longevity, and understanding how they act, will provide insights into aging and metabolism, and strategies for developing agents that prevent chronic disease. The garlic-derived thioallyl compounds S-allylcysteine (SAC) and S-allylmercaptocysteine (SAMC) have been shown to have multiple biological activities. Here we show that SAC and SAMC increase lifespan and stress resistance in Caenorhabditis elegans and reduce accumulation of reactive oxygen species (ROS). These compounds do not appear to activate DAF-16 (FOXO orthologue) or mimic dietary restriction (DR) effects, but selectively induce SKN-1 (Nrf1/2/3 orthologue) targets involved in oxidative stress defense. Interestingly, their treatments do not facilitate SKN-1 nuclear accumulation, but slightly increased intracellular SKN-1 levels. Our data also indicate that thioallyl structure and the number of sulfur atoms are important for SKN-1 target induction. Our results indicate that SAC and SAMC may serve as potential agents that slow aging.

  11. Glycine in the conserved motif III modulates the thermostability and oxidative stress resistance of peptide deformylase in Mycobacterium tuberculosis.

    Science.gov (United States)

    Narayanan, Sai Shyam; Sokkar, Pandian; Ramachandran, Murugesan; Nampoothiri, Kesavan Madhavan

    2011-07-01

    Peptide deformylase (PDF) catalyses the removal of the N-formyl group from the nascent polypeptide during protein maturation. The PDF of Mycobacterium tuberculosis H37Rv (MtbPDF), overexpressed and purified from Escherichia coli, was characterized as an iron-containing enzyme with stability towards H(2) O(2) and moderate thermostability. Substitution of two conserved residues (G49 and L107) from MtbPDF with the corresponding residues found in human PDF affected its deformylase activity. Among characterized PDFs, glycine (G151) in motif III instead of conserved aspartate is characteristic of M. tuberculosis. Although the G151D mutation in MtbPDF increased its deformylase activity and thermostability, it also affected enzyme stability towards H(2) O(2) . Molecular dynamics and docking results confirmed improved substrate binding and catalysis for the G151D mutant and the study provides another possible molecular basis for the stability of MtbPDF against oxidizing agents. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  12. The prelimbic cortex muscarinic M₃ receptor-nitric oxide-guanylyl cyclase pathway modulates cardiovascular responses in rats.

    Science.gov (United States)

    Fassini, Aline; Antero, Leandro S; Corrêa, Fernando M A; Joca, Sâmia R; Resstel, Leonardo B M

    2015-05-01

    The prelimbic cortex (PL), a limbic structure, sends projections to areas involved in the control of cardiovascular responses. Stimulation of the PL with acetylcholine (ACh) evokes depressor and tachycardiac responses mediated by local PL muscarinic receptors. Early studies demonstrated that stimulation of muscarinic receptors induced nitric oxide (NO) synthesis and cyclic guanosine cyclic monophosphate (cGMP) formation. Hence, this study investigates which PL muscarinic receptor subtype is involved in the cardiovascular response induced by ACh and tests the hypothesis that cardiovascular responses caused by muscarinic receptor stimulation in the PL are mediated by local NO and cGMP formation. PL pretreatment with J104129 (an M3 receptor antagonist) blocked the depressor and tachycardiac response evoked by injection of ACh into the PL. Pretreatment with either pirenzepine (an M1 receptor antagonist) or AF-DX 116 (an M2 and M4 receptor antagonist) did not affect cardiovascular responses evoked by ACh. Moreover, similarly to the antagonism of PL M3 receptors, pretreatment with N(ω)-propyl-L-arginine (an inhibitor of neuronal NO synthase), carboxy-PTIO(S)-3-carboxy-4-hydroxyphenylglicine (an NO scavenger), or 1H-[1,2,4]oxadiazolol-[4,3-a]quinoxalin-1-one (a guanylate cyclase inhibitor) blocked both the depressor and the tachycardiac response evoked by ACh. The current results demonstrate that cardiovascular responses evoked by microinjection of ACh into the PL are mediated by local activation of the M3 receptor-NO-guanylate cyclase pathway. © 2015 Wiley Periodicals, Inc.

  13. Rhamnolipids functionalized AgNPs-induced oxidative stress and modulation of toxicity pathway genes in cultured MCF-7 cells.

    Science.gov (United States)

    Dwivedi, Sourabh; Saquib, Quaiser; Al-Khedhairy, Abdulaziz A; Ahmad, Javed; Siddiqui, Maqsood A; Musarrat, Javed

    2015-08-01

    Rhamnolipids extracted from Pseudomonas aeruginosa strain JS-11 were utilized for synthesis of stable silver nanoparticles (Rh-AgNPs). The Rh-AgNPs (23 nm) were characterized by Fourier transform infra-red (FTIR) spectroscopy, atomic force microscopy (AFM) and transmission electron microscopy (TEM). The cytotoxicity assays suggested significant decrease in viability of Rh-AgNPs treated human breast adenocarcinoma (MCF-7) cells, compared with normal human peripheral blood mononuclear (PBMN) cells. Flow cytometry data revealed 1.25-fold (poxidative stress and DNA damage pathways genes viz. BAX, BCl2, Cyclin D1, DNAJA1, E2F transcription factor 1, GPX1 and HSPA4, associated with apoptosis signaling, proliferation and carcinogenesis, pro inflammatory and heat shock responses in Rh-AgNPs treated cells. Thus, the increased ROS production, mitochondrial damage and appearance of sub-G1 (apoptotic) population suggested the anti-proliferative activity, and role of oxidative stress pathway genes in Rh-AgNPs induced death of MCF-7 cancer cells. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Down-modulation of nitric oxide production in murine macrophages treated with crude plant extracts from the Brazilian Cerrado.

    Science.gov (United States)

    Napolitano, D R; Mineo, J R; de Souza, M A; de Paula, J E; Espindola, L S; Espindola, F S

    2005-05-13

    Several plant species from the Cerrado biome in Brazil are popularly used as herbal medicines for its reputed analgesic, anti-acid, anti-microbial, anti-inflammatory and anti-tumoral properties, among others. It has been reported that some plant extracts interfere in the production of nitric oxide (NO), an important inflammatory mediator. In the present study, we investigated the effect of hexanic and ethanolic extracts from three plant species on NO production by LPS/IFN-gamma-activated J774 macrophages based on traditional use. The cytotoxic effect of the crude extracts was determined by the thiazolyl blue test (MTT) to measure cell viability. Serjania lethalis stem extracts and Cupania vernalis leaf extracts significantly inhibited NO production, while extracts from Casearia sylvestris var. lingua were inactive or showed low activity on NO production, or were very cytotoxic. The ethanolic stem bark and leaf extracts of Serjania lethalis and Cupania vernalis, respectively, almost completely inhibited the production of NO by J774 macrophages. It can be concluded that the selected extracts are potential sources of active compounds that might be used as anti-inflammatory agents.

  15. Heteroagglomeration of zinc oxide nanoparticles with clay mineral modulates the bioavailability and toxicity of nanoparticle in Tetrahymena pyriformis.

    Science.gov (United States)

    Gupta, Govind Sharan; Senapati, Violet Aileen; Dhawan, Alok; Shanker, Rishi

    2017-06-01

    The extensive use of zinc oxide nanoparticles (ZnO NPs) in cosmetics, sunscreens and healthcare products increases their release in the aquatic environment. The present study explored the possible interaction of ZnO NPs with montmorillonite clay minerals in aqueous conditions. An addition of ZnO NPs on clay suspension significantly (pclay particles from 1652±90nm to 2158±13nm due to heteroagglomeration. The electrokinetic measurements showed a significant (pclay association (-1.37±0.03μmcm/Vs) that results to the electrostatic interaction between ZnO NPs and clay particles. The attenuated total reflectance Fourier transform infrared spectroscopy analysis of ZnO NPs-clay association demonstrated the binding of ZnO NPs with the Si-O-Al region on the edges of clay particles. The increase in size of ZnO NPs-clay heteroagglomerates further leads to their sedimentation at 24h. Although, the stability of ZnO NPs in the clay suspension was decreased due to heteroagglomeration, but the bioavailability and toxicity of ZnO NPs-clay heteroagglomerates in Tetrahymena pyriformis was enhanced. These observations provide an evidence on possible mechanisms available in natural environment that can facilitate nanoparticles entry into the organisms present in lower trophic levels of the food web. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. A facile and sensitive peptide-modulating graphene oxide nanoribbon catalytic nanoplasmon analytical platform for human chorionic gonadotropin.

    Science.gov (United States)

    Liang, Aihui; Li, Chongning; Li, Dan; Luo, Yanghe; Wen, Guiqing; Jiang, Zhiliang

    2017-01-01

    The nanogold reaction between HAuCl 4 and citrate is very slow, and the catalyst graphene oxide nanoribbon (GONR) enhanced the nanoreaction greatly to produce gold nanoparticles (AuNPs) that exhibited strong surface plasmon resonance (SPR) absorption (Abs) at 550 nm and resonance Rayleigh scattering (RRS) at 550 nm. Upon addition of the peptide of human chorionic gonadotropin (hCG), the peptide could adsorb on the GONR surface, which inhibited the catalysis. When hCG was added, peptides were separated from the GONR surface due to the formation of stable peptide-hCG complex, which led to the activation of GONR catalytic effect. With the increase in hCG concentration, the RRS and Abs signal enhanced linearly. The enhanced RRS value showed a good linear relationship with hCG concentration in the range of 0.2-20 ng/mL, with a detection limit of 70 pg/mL. Accordingly, two new GONR catalytic RRS/Abs methods were established for detecting hCG in serum samples.

  17. Pyrrolidinedithiocarbamate attenuates bleomycin-induced pulmonary fibrosis in rats: Modulation of oxidative stress, fibrosis, and inflammatory parameters.

    Science.gov (United States)

    Zaafan, Mai A; Zaki, Hala F; El-Brairy, Amany I; Kenawy, Sanaa A

    The current study aimed to investigate the modulatory effects of pyrrolidinedithiocarbamate (PDTC; 100 mg/kg) on bleomycin-induced pulmonary fibrosis (5 mg/kg; intratracheal) in rats. Rats were randomly assigned to three groups: normal control, bleomycin control, and PDTC-treated groups. Lung injury was evaluated through histological examination, immunohistochemical detection of inducible nitric oxide synthase (iNOS) in lung tissue and evaluating the total and differential leucocytes count in bronchoalveolar lavage fluid. Lung tissue was used for biochemical assessment of lung content of hydroxyproline, transforming growth factor beta-1 (TGF-β1), tumor necrosis factor-alpha (TNF-α) as well as analysis of lipid peroxides, reduced glutathione (GSH), and total nitrite contents. PDTC attenuated bleomycin-induced pulmonary fibrosis as evidenced by histological observations, decreased iNOS expression and prevention of bleomycin-induced altered total and differential leukocytes count. Additionally, PDTC caused a significant decrease in lung contents of hydroxyproline, TGF-β1, TNF-α, lipid peroxides, and total nitrite coupled with increase in lung GSH content as compared to bleomycin control group. PDTC attenuated bleomycin-induced pulmonary fibrosis in rats via its anti-inflammatory, antioxidant, and antifibrotic activities.

  18. Sodium-coupled neutral amino acid transporter 1 (SNAT1 modulates L-citrulline transport and nitric oxide (NO signaling in piglet pulmonary arterial endothelial cells.

    Directory of Open Access Journals (Sweden)

    Anna Dikalova

    Full Text Available There is evidence that impairments in nitric oxide (NO signaling contribute to chronic hypoxia-induced pulmonary hypertension. The L-arginine-NO precursor, L-citrulline, has been shown to ameliorate pulmonary hypertension. Sodium-coupled neutral amino acid transporters (SNATs are involved in the transport of L-citrulline into pulmonary arterial endothelial cells (PAECs. The functional link between the SNATs, L-citrulline, and NO signaling has not yet been explored.We tested the hypothesis that changes in SNAT1 expression and transport function regulate NO production by modulating eNOS coupling in newborn piglet PAECs.A silencing RNA (siRNA technique was used to assess the contribution of SNAT1 to NO production and eNOS coupling (eNOS dimer-to-monomer ratios in PAECs from newborn piglets cultured under normoxic and hypoxic conditions in the presence and absence of L-citrulline. SNAT1 siRNA reduced basal NO production in normoxic PAECs and prevented L-citrulline-induced elevations in NO production in both normoxic and hypoxic PAECs. SNAT1 siRNA reduced basal eNOS dimer-to-monomer ratios in normoxic PAECs and prevented L-citrulline-induced increases in eNOS dimer-to-monomer ratios in hypoxic PAECs.SNAT1 mediated L-citrulline transport modulates eNOS coupling and thus regulates NO production in hypoxic PAECs from newborn piglets. Strategies that increase SNAT1-mediated transport and supply of L-citrulline may serve as novel therapeutic approaches to enhance NO production in patients with pulmonary vascular disease.

  19. Sodium-coupled neutral amino acid transporter 1 (SNAT1) modulates L-citrulline transport and nitric oxide (NO) signaling in piglet pulmonary arterial endothelial cells.

    Science.gov (United States)

    Dikalova, Anna; Fagiana, Angela; Aschner, Judy L; Aschner, Michael; Summar, Marshall; Fike, Candice D

    2014-01-01

    There is evidence that impairments in nitric oxide (NO) signaling contribute to chronic hypoxia-induced pulmonary hypertension. The L-arginine-NO precursor, L-citrulline, has been shown to ameliorate pulmonary hypertension. Sodium-coupled neutral amino acid transporters (SNATs) are involved in the transport of L-citrulline into pulmonary arterial endothelial cells (PAECs). The functional link between the SNATs, L-citrulline, and NO signaling has not yet been explored. We tested the hypothesis that changes in SNAT1 expression and transport function regulate NO production by modulating eNOS coupling in newborn piglet PAECs. A silencing RNA (siRNA) technique was used to assess the contribution of SNAT1 to NO production and eNOS coupling (eNOS dimer-to-monomer ratios) in PAECs from newborn piglets cultured under normoxic and hypoxic conditions in the presence and absence of L-citrulline. SNAT1 siRNA reduced basal NO production in normoxic PAECs and prevented L-citrulline-induced elevations in NO production in both normoxic and hypoxic PAECs. SNAT1 siRNA reduced basal eNOS dimer-to-monomer ratios in normoxic PAECs and prevented L-citrulline-induced increases in eNOS dimer-to-monomer ratios in hypoxic PAECs. SNAT1 mediated L-citrulline transport modulates eNOS coupling and thus regulates NO production in hypoxic PAECs from newborn piglets. Strategies that increase SNAT1-mediated transport and supply of L-citrulline may serve as novel therapeutic approaches to enhance NO production in patients with pulmonary vascular disease.

  20. Characterization of the galactono-1,4-lactone dehydrogenase from pepper fruits and its modulation in the ascorbate biosynthesis. Role of nitric oxide

    Directory of Open Access Journals (Sweden)

    Marta Rodríguez-Ruiz

    2017-08-01

    Full Text Available Pepper fruit is one of the highest vitamin C sources of plant origin for our diet. In plants, ascorbic acid is mainly synthesized through the L-galactose pathway, being the L-galactono-1,4-lactone dehydrogenase (GalLDH the last step. Using pepper fruits, the full GalLDH gene was cloned and the protein molecular characterization accomplished. GalLDH protein sequence (586 residues showed a 37 amino acids signal peptide at the N-terminus, characteristic of mitochondria. The hydrophobic analysis of the mature protein displayed one transmembrane helix comprising 20 amino acids at the N-terminus. By using a polyclonal antibody raised against a GalLDH internal sequence and immunoblotting analysis, a 56 kDa polypeptide cross-reacted with pepper fruit samples. Using leaves, flowers, stems and fruits, the expression of GalLDH by qRT-PCR and the enzyme activity were analyzed, and results indicate that GalLDH is a key player in the physiology of pepper plants, being possibly involved in the processes which undertake the transport of ascorbate among different organs.We also report that an NO (nitric oxide-enriched atmosphere enhanced ascorbate content in pepper fruits about 40% parallel to increased GalLDH gene expression and enzyme activity. This is the first report on the stimulating effect of NO treatment on the vitamin C concentration in plants. Accordingly, the modulation by NO of GalLDH was addressed. In vitro enzymatic assays of GalLDH were performed in the presence of SIN-1 (peroxynitrite donor and S-nitrosoglutahione (NO donor. Combined results of in vivo NO treatment and in vitro assays showed that NO provoked the regulation of GalLDH at transcriptional and post-transcriptional levels, but not post-translational modifications through nitration or S-nitrosylation events promoted by reactive nitrogen species (RNS took place. These results suggest that this modulation point of the ascorbate biosynthesis could be potentially used for biotechnological

  1. Anisakis pegreffii (Nematoda: Anisakidae products modulate oxidative stress and apoptosis-related biomarkers in human cell lines

    Directory of Open Access Journals (Sweden)

    Concetta Maria Messina

    2016-11-01

    Full Text Available Abstract Background In countries with elevated prevalence of zoonotic anisakiasis and high awareness of this parasitosis, a considerable number of cases that associate Anisakis sp. (Nematoda, Anisakidae and different bowel carcinomas have been described. Although neoplasia and embedded larvae were observed sharing the common site affected by chronic inflammation, no association between the nematode and malignancy were directly proved. Similarly, no data are available about the effect of secretory and excretory products of infecting larvae at the host’s cellular level, except in respect to allergenic interaction. Methods To test the mechanisms by which human non-immune cells respond to the larvae, we exposed the fibroblast cell line HS-68 to two Anisakis products (ES, excretory/secretory products; and EC, crude extract and evaluated molecular markers related to stress response, oxidative stress, inflammation and apoptosis, such as p53, HSP70, TNF-α, c-jun and c-fos, employing cell viability assay, spectrophotometry, immunoblotting and qPCR. Results Both Anisakis products led to increased production of reactive oxygen species (ROS, especially in EC-treated cells. While the ES treatment induces activation of kinases suggesting inflammation and cell proliferation (or inhibition of apoptosis, in EC-treated cells, other signaling pathways indicate the inhibition of apoptosis, marked by strong upregulation of Hsp70. Elevated induction of p53 in fibroblasts treated by both Anisakis products, suggests a significantly negative effect on the host DNA. Conclusions This study shows that in vitro cell response to Anisakis products can result in at least two different scenarios, which in both cases lead to inflammation and DNA damage. Although these preliminary results are far from proving a relationship between the parasite and cancer, they are the first to support the existence of conditions where such changes are feasible.

  2. Anisakis pegreffii (Nematoda: Anisakidae) products modulate oxidative stress and apoptosis-related biomarkers in human cell lines.

    Science.gov (United States)

    Messina, Concetta Maria; Pizzo, Federica; Santulli, Andrea; Bušelić, Ivana; Boban, Mate; Orhanović, Stjepan; Mladineo, Ivona

    2016-11-25

    In countries with elevated prevalence of zoonotic anisakiasis and high awareness of this parasitosis, a considerable number of cases that associate Anisakis sp. (Nematoda, Anisakidae) and different bowel carcinomas have been described. Although neoplasia and embedded larvae were observed sharing the common site affected by chronic inflammation, no association between the nematode and malignancy were directly proved. Similarly, no data are available about the effect of secretory and excretory products of infecting larvae at the host's cellular level, except in respect to allergenic interaction. To test the mechanisms by which human non-immune cells respond to the larvae, we exposed the fibroblast cell line HS-68 to two Anisakis products (ES, excretory/secretory products; and EC, crude extract) and evaluated molecular markers related to stress response, oxidative stress, inflammation and apoptosis, such as p53, HSP70, TNF-α, c-jun and c-fos, employing cell viability assay, spectrophotometry, immunoblotting and qPCR. Both Anisakis products led to increased production of reactive oxygen species (ROS), especially in EC-treated cells. While the ES treatment induces activation of kinases suggesting inflammation and cell proliferation (or inhibition of apoptosis), in EC-treated cells, other signaling pathways indicate the inhibition of apoptosis, marked by strong upregulation of Hsp70. Elevated induction of p53 in fibroblasts treated by both Anisakis products, suggests a significantly negative effect on the host DNA. This study shows that in vitro cell response to Anisakis products can result in at least two different scenarios, which in both cases lead to inflammation and DNA damage. Although these preliminary results are far from proving a relationship between the parasite and cancer, they are the first to support the existence of conditions where such changes are feasible.

  3. Atorvastatin restores arsenic-induced vascular dysfunction in rats: Modulation of nitric oxide signaling and inflammatory mediators

    Energy Technology Data Exchange (ETDEWEB)

    Kesavan, Manickam; Sarath, Thengumpallil Sasindran; Kannan, Kandasamy; Suresh, Subramaniyam; Gupta, Priyanka; Vijayakaran, Karunakaran; Sankar, Palanisamy; Kurade, Nitin Pandurang; Mishra, Santosh Kumar; Sarkar, Souvendra Nath, E-mail: snsarkar1911@rediffmail.com

    2014-10-01

    We evaluated whether atorvastatin, an extensively prescribed statin for reducing the risks of cardiovascular diseases, can reduce the risk of arsenic-induced vascular dysfunction and inflammation in rats and whether the modulation could be linked to improvement in vascular NO signaling. Rats were exposed to sodium arsenite (100 ppm) through drinking water for 90 consecutive days. Atorvastatin (10 mg/kg bw, orally) was administered once daily during the last 30 days of arsenic exposure. On the 91{sup st} day, blood was collected for measuring serum C-reactive protein. Thoracic aorta was isolated for assessing reactivity to phenylephrine, sodium nitroprusside and acetylcholine; evaluating eNOS and iNOS mRNA expression and measuring NO production, while abdominal aorta was used for ELISA of cytokines, chemokine and vascular cell adhesion molecules. Histopathology was done in aortic arches. Arsenic did not alter phenylephrine-elicited contraction. Atorvastatin inhibited E{sub max} of phenylephrine, but it augmented the contractile response in aortic rings from arsenic-exposed animals. Sodium nitroprusside-induced relaxation was not altered with any treatment. However, arsenic reduced acetylcholine-induced relaxation and affected aortic eNOS at the levels of mRNA expression, protein concentration, phosphorylation and NO production. Further, it increased aortic iNOS mRNA expression, iNOS-derived NO synthesis, production of pro-inflammatory mediators (IL-1β, IL-6, MCP-1, VCAM, sICAM) and serum C-reactive protein and aortic vasculopathic lesions. Atorvastatin attenuated these arsenic-mediated functional, biochemical and structural alterations. Results show that atorvastatin has the potential to ameliorate arsenic-induced vascular dysfunction and inflammation by restoring endothelial function with improvement in NO signaling and attenuating production of pro-inflammatory mediators and cell adhesion molecules. - Highlights: • We evaluated if atorvastatin reduce arsenic

  4. SCM-198 attenuates early atherosclerotic lesions in hypercholesterolemic rabbits via modulation of the inflammatory and oxidative stress pathways.

    Science.gov (United States)

    Zhang, Yanfei; Guo, Wei; Wen, Yadan; Xiong, Qinghui; Liu, Hongrui; Wu, Jian; Zou, Yunzeng; Zhu, Yizhun

    2012-09-01

    GPx in the aorta. In a rabbit atherosclerotic model, SCM-198 dose-dependently ameliorated the progression of atherosclerotic lesions and vascular dysfunction accompanied by the suppression of inflammatory factors and oxidative stress. These findings suggested that SCM-198 might be a potential agent for the treatment of atherosclerosis. Crown Copyright © 2012. Published by Elsevier Ireland Ltd. All rights reserved.

  5. Modulation of alveolar macrophage innate response in proinflammatory-, pro-oxidant-, and infection- models by mint extract and chemical constituents: Role of MAPKs.

    Science.gov (United States)

    Yadav, Niket; Chandra, Harish

    2018-01-01

    There is a continuing need for discovering novel primary or adjunct therapeutic agents to treat inflammatory conditions and infections. Natural products have inspired the discovery of several modern therapeutics; however, there is a paucity of mechanistic information on their mode of action. This study investigated the therapeutic potential and mode of action of corn mint's (Mentha arvensis) leaf extract (ME) in alveolar macrophages (AMs) challenged with model pro-inflammatory (LPS), pro- oxidant (LPS or H 2 O 2 ), and infection (Mycobacterium) agents and contribution of its dominant constituents rosmarinic acid, l-menthol, and l-menthone. LPS-induced inflammatory response in the murine AM cell line MH-S was significantly reduced in terms of pro-inflammatory cytokines (TNF-α, IL-1α) and nitric oxide (NO) when pre- or post-treated with ME. The ME pretreatment of macrophages led to a significant increase (P≤0.05) in phagocytic activity toward Mycobacterium smegmatis and a greater pathogen clearance in 24h in both ME pre-treated (P≤0.05) and post-treated cells. Significant attenuation (P≤0.01) of reactive oxygen species (ROS) production in LPS- or H 2 O 2- treated macrophages by pretreatment with whole mint extract (ME) was accounted for in part by the mint constituents rosmarinic acid and l-menthone. Attenuation of pro-inflammatory response by ME pretreatment coincided with the significant reduction in total and phosphorylated JNK1/2, decrease in total p38, and increase in phospho-ERK1/2 thereby implying a role of differential modulation of MAPKs. Taken together, the results demonstrate that corn mint leaf components cause potent anti-inflammatory, anti-oxidant, and anti-infection effects in AMs via suppression of the production of cytokines/soluble mediators and ROS and increased pathogen clearance, respectively. To our knowledge, this is the first report on the mode of action of corn mint targeting the alveolar macrophages and on the potential role of MAPKs

  6. GABA-BZD Receptor Modulating Mechanism of Panax quinquefolius against 72-hours Sleep Deprivation Induced Anxiety like Behavior: Possible Roles of Oxidative Stress, Mitochondrial Dysfunction and Neuroinflammation

    Directory of Open Access Journals (Sweden)

    Priyanka eChanana

    2016-03-01

    Full Text Available ABSTRACTRationale- Panax quinquefolius (American Ginseng is known for its therapeutic potential against various neurological disorders, but its plausible mechanism of action still remains undeciphered. GABA (Gamma Amino Butyric Acid plays an important role in sleep wake cycle homeostasis. Thus there exists rationale in exploring the GABA-ergic potential of Panax quinquefolius as neuroprotective strategy in sleep deprivation induced secondary neurological problems.Objective- The present study was designed to explore the possible GABA-ergic mechanism in the neuro-protective effect of Panax quinquefolius against 72-hours sleep deprivation induced anxiety like behaviour, oxidative stress, mitochondrial dysfunction, HPA-axis activation and neuroinflammation.Materials and Methods- Male laca mice were sleep deprived for 72-hours by using Grid suspended over water method. Panax quinquefolius (American Ginseng 50, 100 and 200 mg/kg was administered alone and in combination with GABA modulators (GABA Cl- channel inhibitor, GABA-benzodiazepine receptor inhibitor and GABAA agonist for 8 days, starting five days prior to 72-hours sleep deprivation period. Various behavioural (locomotor activity, mirror chamber test, biochemical (lipid peroxidation, reduced glutathione, catalase, nitrite levels, mitochondrial complexes, neuroinflammation marker (Tumour Necrosis Factor, TNF-alpha, serum corticosterone, and histopathological sections of brains were assessed. Results- 72-hours sleep deprivation significantly impaired locomotor activity, caused anxiety-like behaviour, conditions of oxidative stress, alterations in mitochondrial enzyme complex activities, raised serum corticosterone levels, brain TNFα levels and led to neuroinflammation like signs in discrete brain areas as compared to naive group. Panax quinquefolius (100 and 200 mg/kg treatment restored the behavioural, biochemical, mitochondrial, molecular and histopathological alterations. Pre-treatment of

  7. The renoprotective effect of L-carnitine in hypertensive rats is mediated by modulation of oxidative stress-related gene expression.

    Science.gov (United States)

    Zambrano, Sonia; Blanca, Antonio Jesús; Ruiz-Armenta, María Victoria; Miguel-Carrasco, José Luis; Revilla, Elisa; Santa-María, Consuelo; Mate, Alfonso; Vázquez, Carmen María

    2013-09-01

    Arterial hypertension is associated with a high production of reactive oxygen species and a decrease in the antioxidant defense systems. Based on the lack of toxicity of L-carnitine (LC) and previous studies reporting beneficial effects of this compound in experimental models of hypertension, the aim of this work was to test the hypothesis that LC might protect the kidney against hypertension-induced oxidative damage, as well as to investigate the mechanisms involved in this effect. To this end, specific activities and protein/mRNA expression of the antioxidant enzymes (glutathione peroxidase, glutathione reductase, and superoxide dismutase), and those of NADPH oxidase (the main responsible for superoxide anion production in renal tissue) have been measured in renal cortex homogenates from NG-nitro-L-arginine methyl ester (L-NAME)-treated rats and control normotensive rats. In addition, components of the renin-angiotensin system (RAS) and redox-sensitive transcription factors (NF-κB, Nrf2, and PPARα) have also been evaluated. Male Wistar rats aged 6-8 weeks were divided into four groups of six animals each: (1) control, normotensive Wistar rats (with free access to tap water); (2) Wistar rats subjected to treatment with 25 mg of L-NAME/kg body weight/day dissolved in the drinking water, in order to develop L-NAME-induced hypertension; (3) Wistar rats subjected to treatment with 400 mg of LC/kg body weight/day (also dissolved in the drinking water); and (4) L-NAME-treated rats subjected to simultaneous treatment with LC at the indicated doses. The beneficial effect of LC supplementation on oxidative damage in the renal cortex of hypertensive rats reversed hypertension-associated renal function damage and produced an upregulation of both antioxidant enzymes and eNOS, and with a downregulation of both NADPH oxidase and RAS components. LC improves the oxidative stress response through a specific modulation of NF-κB, Nrf2, and PPARα transcription factors. Thus, the

  8. Correlation of Local Structure and Diffusion Pathways in the Modulated Anisotropic Oxide Ion Conductor CeNbO4.25

    KAUST Repository

    Pramana, Stevin S.

    2016-01-15

    CeNbO is reported to exhibit fast oxygen ion diffusion at moderate temperatures, making this the prototype of a new class of ion conductor with applications in a range of energy generation and storage devices. To date, the mechanism by which this ion transport is achieved has remained obscure, in part due to the long-range commensurately modulated structural motif. Here we show that CeNbO forms with a unit cell 12 times larger than the stoichiometric tetragonal parent phase of CeNbO as a result of the helical ordering of Ce and Ce ions along z. Interstitial oxygen ion incorporation leads to a cooperative displacement of the surrounding oxygen species, creating interlayer NbO connectivity by extending the oxygen coordination number to 7 and 8. Molecular dynamic simulations suggest that fast ion migration occurs predominantly within the xz plane. It is concluded that the oxide ion diffuses anisotropically, with the major migration mechanism being intralayer; however, when obstructed, oxygen can readily move to an adjacent layer along y via alternate lower energy barrier pathways.

  9. Azadirachta indica acts as a pro-oxidant and modulates cell cycle associated proteins during DMBA/TPA induced skin carcinogenesis in mice.

    Science.gov (United States)

    Arora, N; Bansal, M P; Koul, A

    2013-07-01

    The present study was designed to determine the modulatory effect of aqueous Azadirachta indica leaf extract (AAILE) on cell cycle-associated proteins during two-stage skin carcinogenesis in mice. Considering the dual role of reactive oxygen species in cancer and its chemoprevention, the levels of lipid peroxidation (index of peroxidative damage) were also determined. Skin tumours were induced by topical application of 7,12-dimethylbenz(a)anthracene (DMBA) as a carcinogen followed by the repetitive application of 12-O-tetradecanoylphorbol-13-acetate (TPA) as a promoter. Skin tumours obtained in the DMBA/TPA group exhibited enhanced expression of proliferating cell nuclear antigen (PCNA, index of proliferation), p21 and cyclin D1, with no alterations in p53 expression in comparison to the control group. Tumours in AAILE + DMBA/TPA group exhibited low PCNA and cyclin D1 expression and enhanced expression of p53 and p21 in comparison to the DMBA/TPA group. The skin tumours obtained in the AAILE + DMBA/TPA group exhibited high lipid peroxidation levels in comparison to the tumours obtained in the DMBA/TPA group. The observations of the present study suggest that AAILE behaves as a pro-oxidant in the tumours, thereby rendering them susceptible to damage, which eventually culminates into its anti-neoplastic action. Also, cell cycle regulatory proteins may be modulated by AAILE and could affect the progression of cells through the cell cycle. Copyright © 2012 John Wiley & Sons, Ltd.

  10. microRNA expression profiling and functional annotation analysis of their targets modulated by oxidative stress during embryonic heart development in diabetic mice.

    Science.gov (United States)

    Dong, Daoyin; Zhang, Yuji; Reece, E Albert; Wang, Lei; Harman, Christopher R; Yang, Peixin

    2016-10-01

    Maternal pregestational diabetes mellitus (PGDM) induces congenital heart defects (CHDs). The molecular mechanism underlying PGDM-induced CHDs is unknown. microRNAs (miRNAs), small non-coding RNAs, repress gene expression at the posttranscriptional level and play important roles in heart development. We performed a global miRNA profiling study to assist in revealing potential miRNAs modulated by PGDM and possible developmental pathways regulated by miRNAs during heart development. A total of 149 mapped miRNAs in the developing heart were significantly altered by PGDM. Bioinformatics analysis showed that the majority of the 2111 potential miRNA target genes were associated with cardiac development-related pathways including STAT3 and IGF-1 and transcription factors (Cited2, Zeb2, Mef2c, Smad4 and Ets1). Overexpression of the antioxidant enzyme, superoxide dismutase 1, reversed PGDM-altered miRNAs, suggesting that oxidative stress is responsible for dysregulation of miRNAs. Thus, our study provides the foundation for further investigation of a miRNA-dependent mechanism underlying PGDM-induced CHDs. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. L-3-n-Butylphthalide Protects HSPB8 K141N Mutation-Induced Oxidative Stress by Modulating the Mitochondrial Apoptotic and Nrf2 Pathways

    Directory of Open Access Journals (Sweden)

    Xiao-Dong Yang

    2017-07-01

    Full Text Available Charcot–Marie–Tooth disease (CMT, also known as hereditary motor and sensory neuropathy, is the most common inherited peripheral nerve disorder. Missense mutations, such as K141N, in the small heat shock protein HSPB8 are known to cause distal hereditary motor neuropathy 2A (dHMN2A or Charcot-Marie-Tooth neuropathy type 2L (CMT2L. However, of critical clinical significance, very few specific therapies for this disease exist. In the present study, we investigated the impact of mutant K141N HSPB8 on mitochondrial distribution and function in a cellular model of CMT2L. Our results indicate that K141N HSPB8 induced mitochondrial aggregation and caused increased oxidative stress injury. As an extraction from Chinese celery Apium graveolens Linn seeds, L-3-n-Butylphthalide (NBP, has been reported to exert many neuroprotective effects, we interrogated whether NBP could elicit a protective effect on the cell injury typically caused by HSPB8 K141N mutations. We found NBP could reverse the pathological processes induced by HSPB8 K141N mutation via an antioxidant effect, modulation of the Bax/Bcl-2 mitochondrial apoptotic and Nrf2 pathways. We propose a novel function of HSPB8, highlighting the consequence of the K141N pathogenic mutation. Furthermore, we suggest NBP may have promising therapeutic potential in the treatment of CMT2L.

  12. Polyphenol fraction of extra virgin olive oil protects against endothelial dysfunction induced by high glucose and free fatty acids through modulation of nitric oxide and endothelin-1

    Directory of Open Access Journals (Sweden)

    Carolina Emilia Storniolo

    2014-01-01

    Full Text Available Epidemiological and clinical studies have reported that olive oil reduces the incidence of cardiovascular disease. However, the mechanisms involved in this beneficial effect have not been delineated. The endothelium plays an important role in blood pressure regulation through the release of potent vasodilator and vasoconstrictor agents such as nitric oxide (NO and endothelin-1 (ET-1, respectively, events that are disrupted in type 2 diabetes. Extra virgin olive oil contains polyphenols, compounds that exert a biological action on endothelial function. This study analyzes the effects of olive oil polyphenols on endothelial dysfunction using an in vitro model that simulates the conditions of type 2 diabetes. Our findings show that high glucose and linoleic and oleic acids decrease endothelial NO synthase phosphorylation, and consequently intracellular NO levels, and increase ET-1 synthesis by ECV304 cells. These effects may be related to the stimulation of reactive oxygen species production in these experimental conditions. Hydroxytyrosol and the polyphenol extract from extra virgin olive oil partially reversed the above events. Moreover, we observed that high glucose and free fatty acids reduced NO and increased ET-1 levels induced by acetylcholine through the modulation of intracellular calcium concentrations and endothelial NO synthase phosphorylation, events also reverted by hydroxytyrosol and polyphenol extract. Thus, our results suggest a protective effect of olive oil polyphenols on endothelial dysfunction induced by hyperglycemia and free fatty acids.

  13. Astaxanthin from shrimp efficiently modulates oxidative stress and allied cell death progression in MCF-7 cells treated synergistically with β-carotene and lutein from greens.

    Science.gov (United States)

    Sowmya, Poorigali Raghavendra-Rao; Arathi, Bangalore Prabhashankar; Vijay, Kariyappa; Baskaran, Vallikannan; Lakshminarayana, Rangaswamy

    2017-08-01

    This study investigated the synergistic efficacy of keto-carotenoid astaxanthin (AST, from shrimp) plus hydrocarbon (β-carotene, BC) and hydroxyl (lutein, L) carotenoids (from greens) on molecular events in MCF-7 cells. MCF-7 cells were treated with either of carotenoid (20 μM, AST or BC or L) separately or the mixture of them (an equimolar concentration of carotenoids mixture, CM) or saponified carotenoid extract from shrimp (SSCE) for 48 h and analyzed cellular uptake, cytotoxicity, and apoptosis. The IC 50 and combination-index values of AST co-treatment with a lower concentration of BC and L (5 μM) exhibited enhanced cytotoxicity and oxidative stress as compared with individual carotenoids or SSCE. Further, higher cellular uptake/accumulation of AST along with BC and L found to synergistically induce apoptosis through modulation of cyclin D1, p53, Bax and Bcl-2 expressions by arresting cell cycle at G0/G1 phase. Further, CM or SSCE treatments are unlikely to affect proliferation of normal breast epithelial cells (MCF-10A). The results of selective killing of MCF-7 cells demonstrated a greater insight on the synergistic effect of shrimp AST plus BC and L. It is concluded that consumption of shrimp along with green leafy vegetables helps in combating cancer chemoprevention. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Oxidized lipoproteins induce long-lasting inhibition of nitric oxide synthase from a murine endothelioma cell line (bEnd.4).

    Science.gov (United States)

    Fogliatto, G; Musanti, R; Pirillo, A; Ghiselli, G

    1995-04-01

    The vascular endothelium produces nitric oxide, which has vasodilatory properties. It has been postulated that some lipoproteins may increase arterial vascular tone by decreasing the availability of endothelium-derived nitric oxide. The mechanism underlying this effect, however, is still poorly understood. We investigated the effect of native and oxidized human low- and high-density lipoproteins on the nitric oxide synthetic activity of an endothelioma cell line (bEnd.4). Oxidized lipoproteins were obtained by incubation with CuSO4. The production of nitric oxide by the cells was monitored by quantifying the nitrite concentration in the medium using Greiss reagent. The synthesis of nitric oxide by the bEnd.4 cell line was calcium-dependent and was abolished by a selective inhibitor of the constitutive nitric oxide synthase. Incubation with oxidized lipoproteins caused a time- and dose-dependent inhibition of nitric oxide synthetic activity. At a concentration of 100 micrograms/ml cholesterol, oxidized low- and high-density lipoproteins inhibited the production of nitric oxide by 27 and 51%, respectively, within 6h. The lipid fraction obtained from the native or the oxidized lipoproteins mimicked the effect of the intact lipoproteins. These results support the involvement of oxidized lipoproteins in the modulation of endothelial functions relevant to the pathogenesis of cardiovascular disease.

  15. Optical modulator including grapene

    Science.gov (United States)

    Liu, Ming; Yin, Xiaobo; Zhang, Xiang

    2016-06-07

    The present invention provides for a one or more layer graphene optical modulator. In a first exemplary embodiment the optical modulator includes an optical waveguide, a nanoscale oxide spacer adjacent to a working region of the waveguide, and a monolayer graphene sheet adjacent to the spacer. In a second exemplary embodiment, the optical modulator includes at least one pair of active media, where the pair includes an oxide spacer, a first monolayer graphene sheet adjacent to a first side of the spacer, and a second monolayer graphene sheet adjacent to a second side of the spacer, and at least one optical waveguide adjacent to the pair.

  16. Zinc oxide nanoparticles modulates the production of β-glucosidase and protects its functional state under alcoholic condition in Saccharomyces cerevisiae.

    Science.gov (United States)

    Ban, Deependra Kumar; Paul, Subhankar

    2014-05-01

    In the present investigation, we have investigated the effect of zinc oxide nanoparticles (ZnONP) on the production of β-glucosidase (BGL) in Saccharomyces cerevisiae under various conditions. ZnONP was synthesized chemically and characterized using various standard techniques. The results revealed that yeast culture administered with 5 mM ZnONP enhanced the intracellular BGL activity up to 28 % compared to control with simultaneous growth of cells. However, at a higher dose of ZnONP (10 and 15 mM), both the activity of the enzyme and yeast growth was dropped. When yeast cells were grown in alcoholic medium (2, 5, and 10 % ethanol), the growth was found inhibited with substantial reduction of intracellular BGL activity. Interestingly, the administration of ZnONP further inhibited the cell growth, however, suppressed the alcoholic effect on enzyme activity. Moreover, under the same condition, ZnONP enhanced the biological activity of the enzyme in cells, indicated a higher yield of BGL production. When the mechanism of ZnONP-mediated cell growth inhibition was investigated, N-acetylcysteine (NAC)-based cell growth study proved that reactive oxygen species (ROS) was not the sole cell death mechanism induced by ZnONP, indicating a second mechanism of cell death. Our findings provide a new insight on the potential application of ZnONP as an external supplement to enhance the active production of BGL like important industrial enzyme in S. cerevisiae in both normal and alcohol stressed condition as well as to produce baker’s yeast in higher amount.

  17. Hadrons in medium

    Indian Academy of Sciences (India)

    medium properties of hadrons. I discuss the relevant symmetries of QCD and how they might affect the observed hadron properties. I then discuss at length the observable consequences of in-medium changes of hadronic properties in reactions with ...

  18. Medium is the message

    NARCIS (Netherlands)

    Kuipers, G.; Ritzer, G.

    2012-01-01

    "The medium is the message" is a phrase coined by Canadian media theorist Marshall McLuhan (1911-1980), in his book Understanding Media: The Extensions of Man (1964). In this book, McLuhan examines the impact of media on societies and human relations, arguing for the primacy of the medium -

  19. Perfusion Bioreactor Module

    Science.gov (United States)

    Morrison, Dennis R.

    1990-01-01

    Perfusion bioreactor module, self-contained, closed-loop cell-culture system that operates in microgravity or on Earth. Equipment supports growth or long-term maintenance of cultures of human or other fragile cells for experiments in basic cell biology or process technology. Designed to support proliferation (initially at exponential rates of growth) of cells in complex growth medium and to maintain confluent cells in defined medium under conditions optimized to permit or encourage selected functions of cells, including secretion of products of cells into medium.

  20. Soluble iron modulates iron oxide particle-induced inflammatory responses via prostaglandin E2 synthesis: In vitro and in vivo studies

    Directory of Open Access Journals (Sweden)

    Mayer Paula

    2009-12-01

    Full Text Available Abstract Background Ambient particulate matter (PM-associated metals have been shown to play an important role in cardiopulmonary health outcomes. To study the modulation of PM-induced inflammation by leached off metals, we investigated intracellular solubility of radio-labeled iron oxide (59Fe2O3 particles of 0.5 and 1.5 μm geometric mean diameter. Fe2O3 particles were examined for the induction of the release of interleukin 6 (IL-6 as pro-inflammatory and prostaglandin E2 (PGE2 as anti-inflammatory markers in cultured alveolar macrophages (AM from Wistar Kyoto (WKY rats. In addition, we exposed male WKY rats to monodispersed Fe2O3 particles by intratracheal instillation (1.3 or 4.0 mg/kg body weight to examine in vivo inflammation. Results Particles of both sizes are insoluble extracellularly in the media but moderately soluble in AM with an intracellular dissolution rate of 0.0037 ± 0.0014 d-1 for 0.5 μm and 0.0016 ± 0.0012 d-1 for 1.5 μm 59Fe2O3 particles. AM exposed in vitro to 1.5 μm particles (10 μg/mL for 24 h increased IL-6 release (1.8-fold; p 2 synthesis (1.9-fold; p 2 synthesis (2.5-fold, p 2 synthesis by indomethacin caused a pro-inflammatory phenotype as noted by increased IL-6 release from AM exposed to 0.5 μm particles (up to 3-fold; p Conclusions Fe2O3 particle-induced neutrophilic inflammatory response in vivo and pro-inflammatory cytokine release in vitro might be modulated by intracellular soluble iron via PGE2 synthesis. The suppressive effect of intracellular released soluble iron on particle-induced inflammation has implications on how ambient PM-associated but soluble metals influence pulmonary toxicity of ambient PM.

  1. Scalability and stability of very thin roll-to-roll processed large area indium-tin-oxide free polymer solar cell modules

    DEFF Research Database (Denmark)

    Angmo, Dechan; Gevorgyan, Suren; Larsen-Olsen, Thue Trofod

    2013-01-01

    Polymer solar cell modules were prepared directly on thin flexible barrier polyethylene terephthalate foil. The performance of the modules was found to be scalable from a single cell with an area of 6 cm2 to modules with a total area of up to 186 cm2. The substrate thickness was also explored and...

  2. Modulation of the excited-electron recombination process by introduce g-C3N4 on Bi-based bimetallic oxides photocatalyst

    Science.gov (United States)

    Liu, Duanduan; Jin, Zhiliang; Li, Hongxuan; Lu, Gongxuan

    2017-11-01

    The Bi-based bimetallic oxides photocatalyst Bi7.53Co0.47O11.92 was successfully synthesized and the graphite phase carbon nitride (g-C3N4) was loaded, and a novel composite photocatalyst Bi7.53Co0.47O11.92/g-C3N4 was obtained as well. The photocatalyst Bi7.53Co0.47O11.92, possessed tetragonal crystal structure, with the introduction of g-C3N4, the H2 production reached the maximum about 108 μmol under continuous visible light irradiation for 4 h, which was 13 times higher than that of pure g-C3N4 photocatalyst. A series of studies shown that the g-C3N4 on the surface of Bi7.53Co0.47O11.92 provided the more active sites and improved the efficiency of photo-generated charge separation by means of several characterizations such as SEM, XRD, XPS, element mapping, UV-vis DRS and FTIR. etc. and the results of which were in good agreement with each other. The composite photocatalyst Bi7.53Co0.47O11.92 has a greater specific surface area and pore volume compared to pure g-C3N4, which is more favorable for the adsorption of dye molecules, leading to enhance the composite photocatalytic activity consequently. The excited-electron recombination process was greatly modulated with the introduce g-C3N4 on the surface of Bi-based bimetallic oxides photocatalyst and the photostability was enhanced as well. The promoted charge separation was measured by means of the EIS, photocurrent and transient fluorescence. In addition, a possible reaction mechanism over eosin Y-sensitized Bi7.53Co0.47O11.92/g-C3N4 photocatalyst under visible light irradiation was proposed.

  3. Deciphering the interplay between cysteine synthase and thiol cascade proteins in modulating Amphotericin B resistance and survival of Leishmania donovani under oxidative stress

    Directory of Open Access Journals (Sweden)

    Kuljit Singh

    2017-08-01

    Full Text Available Leishmania donovani is the causative organism of the neglected human disease known as visceral leishmaniasis which is often fatal, if left untreated. The cysteine biosynthesis pathway of Leishmania may serve as a potential drug target because it is different from human host and regulates downstream components of redox metabolism of the parasites; essential for their survival, pathogenicity and drug resistance. However, despite the apparent dependency of redox metabolism of cysteine biosynthesis pathway, the role of L. donovani cysteine synthase (LdCS in drug resistance and redox homeostasis has been unexplored. Herein, we report that over-expression of LdCS in Amphotericin B (Amp B sensitive strain (S1-OE modulates resistance towards oxidative stress and drug pressure. We observed that antioxidant enzyme activities were up-regulated in S1-OE parasites and these parasites alleviate intracellular reactive oxygen species (ROS efficiently by maintaining the reduced thiol pool. In contrast to S1-OE parasites, Amp B sensitive strain (S1 showed higher levels of ROS which was positively correlated with the protein carbonylation levels and negatively correlated with cell viability. Moreover, further investigations showed that LdCS over-expression also augments the ROS-primed induction of LdCS-GFP as well as endogenous LdCS and thiol pathway proteins (LdTryS, LdTryR and LdcTXN in L. donovani parasites; which probably aids in stress tolerance and drug resistance. In addition, the expression of LdCS was found to be up-regulated in Amp B resistant isolates and during infective stationary stages of growth and consistent with these observations, our ex vivo infectivity studies confirmed that LdCS over-expression enhances the infectivity of L. donovani parasites. Our results reveal a novel crosstalk between LdCS and thiol metabolic pathway proteins and demonstrate the crucial role of LdCS in drug resistance and redox homeostasis of Leishmania. Keywords

  4. Evaluation of hemostasis parameters and the role of the oxidative damage to plasma proteins in the modulation of hemostasis in patients with nephrolithiasis before and after extracorporeal shock wave lithotripsy.

    Science.gov (United States)

    Woźniak, Paweł; Kontek, Bogdan; Różański, Waldemar; Olas, Beata

    2017-01-01

    Extracorporeal shock wave lithotripsy (ESWL) is a commonly-used method in urology, which may modulate hemostasis and may induce lipid peroxidation in patients with nephrolithiasis. However, previous studies only examine changes occurring in patients 30-2