Comparison of effect of vitamin E-coated dialyzer and oral vitamin E on hemodialysis-induced Cu/Zn-superoxide dismutase.

PubMed

Akiyama, Shinichiro; Inagaki, Masahiro; Tsuji, Mayumi; Gotoh, Hiromichi; Gotoh, Tomomi; Washio, Kazunori; Gotoh, Yoshikazu; Oguchi, Katsuji

2005-01-01

We reported earlier that production of Cu/Zn-superoxide dismutase (SOD) increases markedly in hemodialysis patients but not in non-dialyzed chronic renal failure (CRF) patients. In this study, we compared the antioxidant effects of oral vitamin E supplementation (VE-PO) and vitamin E coating of a dialyzer (VE-BMD) by measuring increased Cu/Zn-SOD in hemodialysis patients. 31 hemodialysis patients were divided into two groups: 16 hemodialysis patients underwent usual dialysis with vitamin E supplementation 600 mg/day while 15 others were dialyzed using vitamin E-coated membrane for 6 months. Total plasma SOD activity was determined by NBT method, plasma Cu/Zn-SOD contents by ELISA and Cu/Zn-SOD mRNA in leukocytes by RT-PCR. VE-PO and VE-BMD showed almost comparable effects on Cu/Zn-SOD contents and its mRNA levels in hemodialysis patients. VE-PO resulted in a progressive decrease of Cu/Zn-SOD content (p < 0.001). A comparable progressive decrease was observed also in VE-BMD (p < 0.0001). Both VE-PO and VE-BMD resulted in a progressive decrease of Cu/Zn-SOD mRNA (p < 0.01), which reached the level of non-dialyzed CRF patients. Copyright (c) 2005 S. Karger AG, Basel.

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

PubMed Central

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

2016-01-01

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

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

DOE PAGES

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

2016-08-17

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

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

PubMed

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

1992-01-05

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

Characteristics of the Copper,Zinc Superoxide Dismutase of a Hadal Sea Cucumber (Paelopatides sp.) from the Mariana Trench.

PubMed

Li, Yanan; Kong, Xue; Chen, Jiawei; Liu, Helu; Zhang, Haibin

2018-05-18

Superoxide dismutases (SODs) are among the most important antioxidant enzymes and show great potential in preventing adverse effects during therapeutic trials. In the present study, cloning, expression, and characterization of a novel Cu,Zn superoxide dismutase (Ps-Cu,Zn-SOD) from a hadal sea cucumber ( Paelopatides sp.) were reported. Phylogenetic analysis showed that Ps-Cu,Zn-SOD belonged to a class of intracellular SOD. Its K m and V max were 0.0258 ± 0.0048 mM and 925.1816 ± 28.0430 units/mg, respectively. The low K m value of this enzyme represents a high substrate affinity and can adapt to the low metabolic rate of deep sea organisms. The enzyme functioned from 0 °C to 80 °C with an optimal temperature of 40 °C. Moreover, the enzyme activity was maintained up to 87.12% at 5 °C. The enzyme was active at pH 4 to 12 with an optimal pH of 8.5. Furthermore, Ps-Cu,Zn-SOD tolerated high concentration of urea and GuHCl, resisted hydrolysis by proteases, and maintained stability at high pressure. All these features demonstrated that the deep sea Ps-Cu,Zn-SOD is a potential candidate for application to the biopharmaceutical field.

Effect of intradermal human recombinant copper-zinc superoxide dismutase on random pattern flaps in rats.

PubMed

Schein, Ophir; Westreich, Melvyn; Shalom, Avshalom

2013-09-01

Studies have focused on enhancing flap viability using superoxide dismutase (SOD), but only a few used SOD from human origin, and most gave the compound systemically. We evaluated the ability of SOD to improve random skin flap survival using human recombinant copper-zinc superoxide dismutase (Hr-CuZnSOD) in variable doses, injected intradermally into the flap. Seventy male Sprague Dawley rats were randomly assigned into 4 groups. Cephalic random pattern flaps were elevated on their backs and intradermal injections of different dosages of Hr-CuZnSOD were given 15 minutes before surgery. Flap survival was evaluated by fluorescein fluorescence. Analysis of variance (ANOVA) and t test statistical analyses were performed. Flap survival in all treated groups was significantly better than in the controls. The beneficial effect of HR-CuZnSOD on flap survival is attained when it is given intradermally into the flap tissue. Theoretically, Hr-CuZnSOD delivered with local anesthetics used in flap elevation may be a valuable clinical tool. Copyright © 2012 Wiley Periodicals, Inc.

Novel inhibitors to Taenia solium Cu/Zn superoxide dismutase identified by virtual screening

NASA Astrophysics Data System (ADS)

García-Gutiérrez, P.; Landa-Piedra, A.; Rodríguez-Romero, A.; Parra-Unda, R.; Rojo-Domínguez, A.

2011-12-01

We describe in this work a successful virtual screening and experimental testing aimed to the identification of novel inhibitors of superoxide dismutase of the worm Taenia solium ( TsCu/Zn-SOD), a human parasite. Conformers from LeadQuest® database of drug-like compounds were selected and then docked on the surface of TsCu/Zn-SOD. Results were screened looking for ligand contacts with receptor side-chains not conserved in the human homologue, with a subsequent development of a score optimization by a set of energy minimization steps, aimed to identify lead compounds for in vitro experiments. Six out of fifty experimentally tested compounds showed μM inhibitory activity toward TsCu/Zn-SOD. Two of them showed species selectivity since did not inhibit the homologous human enzyme when assayed in vitro.

Identification of novel superoxide dismutase isoenzymes in the olive (Olea europaea L.) pollen.

PubMed

Zafra, Adoración; Castro, Antonio Jesús; Alché, Juan de Dios

2018-06-08

Among antioxidant enzymes, the superoxide dismutase (SOD) family is a major actor in catalysing the disproportionation of superoxide. Apart from its role as antioxidant, these enzymes have a role in cell signalling, and Cu,Zn-SOD proteins are also major pollen allergens. In order to deepen our understanding of the SOD isoenzymes present in olive pollen and to analyse the molecular variability of the pollen Cu,Zn-SOD family, we carried out biochemical, transcriptomic and localization studies of pollen grains from different olive cultivars and other allergenic species. Olive pollen showed a high rate of total SOD activity in all cultivars assayed, which did not correlate with pollen viability. Mass spectrometry analysis together with activity assays and Western blotting experiments enabled us to identify new forms of Cu,Zn-SOD enzyme (including chloroplastidic and peroxisomal forms) as well as differentially expressed Mn-, Fe- and Cu,Zn-SOD isoenzymes among the pollen of different olive cultivars and allergenic species. Ultrastructural localization of Cu,Zn-SOD revealed its plastidial localization in the pollen grain. We also identified the occurrence of a shorter form of one of the cytosolic Cu,Zn-SOD enzymes, likely as the result of alternative splicing. This shorter enzyme showed lower SOD activity as compared to the full length form. The presence of multiple SOD isoenzymes in the olive pollen could be related to the need of finely tuning the ROS metabolism during the transition from its quiescent condition at maturity to a highly metabolically active state at germination.

E.s.r., magnetic, optical and biological (SOD and antimicrobial) studies of imidazolate bridged Cu II-Zn II and Cu II-Ni II complexes with tris(2-amino ethyl)amine as capping ligand: a plausible model for superoxide dismutase

NASA Astrophysics Data System (ADS)

Singh, Nripendra; Shukla, K. K.; Patel, R. N.; Chauhan, U. K.; Shrivastava, R.

2003-11-01

X-band e.s.r. and optical absorption spectra of the imidazolate bridged heterobimetallic complexes [(tren)Cu-E-Im-Zn-(tren)](ClO 4) 3 and [(tren)Cu-E-Im-Ni-(tren)](ClO 4) 3, where trentris(2-aminoethyl)amine, E-Im=2-ethylimidazolate ion and the related mononuclear complexes [Cu(tren)](ClO 4) 2 and [(tren)Cu-E-ImH)](ClO 4) 2 have been described. Biological activities (superoxide dismutase and antimicrobial) have also been measured and compared with reported complexes.

Peroxisomal copper, zinc superoxide dismutase. Characterization of the isoenzyme from watermelon cotyledons.

PubMed Central

Bueno, P; Varela, J; Gimeénez-Gallego, G; del Río, L A

1995-01-01

The biochemical and immunochemical characterization of a superoxide dismutase (SOD, EC 1.15.1.1) from peroxisomal origin has been carried out. The enzyme is a Cu,Zn-containing SOD (CuZn-SOD) located in the matrix of peroxisomes from watermelon (Citrullus vulgaris Schrad.) cotyledons (L.M. Sandalio and L.A. del Río [1988] Plant Physiol 88: 1215-1218). The amino acid composition of the enzyme was determined. Analysis by reversed-phase high-performance liquid chromatography of the peroxisomal CuZn-SOD incubated with 6 M guanidine-HCl indicated that this enzyme contained a noncovalently bound chromophore group that was responsible for the absorbance peak of the native enzyme at 260 nm. The amino acid sequence of the peroxisomal CuZn-SOD was determined by Edman degradation. Comparison of its sequence with those reported for other plant SODs revealed homologies of about 70% with cytosolic CuZn-SODs and of 90% with chloroplastic CuZn-SODs. The peroxisomal SOD has a high thermal stability and resistance to inactivation by hydrogen peroxide. A polyclonal antibody was raised against peroxisomal CuZn-SOD, and by western blotting the antibody cross-reacted with plant CuZn-SODs but did not recognize either plant Mn-SOD or bacterial Fe-SOD. The antiSOD-immunoglobulin G showed a weak cross-reaction with bovine erythrocytes and liver CuZn-SODs, and also with cell-free extracts from trout liver. The possible function of this CuZn-SOD in the oxidative metabolism of peroxisomes is discussed. PMID:7630940

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

PubMed

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

1984-03-29

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

Isolation, Chromosomal Localization, and Differential Expression of Mitochondrial Manganese Superoxide Dismutase and Chloroplastic Copper/Zinc Superoxide Dismutase Genes in Wheat1

PubMed Central

Wu, Guohai; Wilen, Ronald W.; Robertson, Albert J.; Gusta, Lawrence V.

1999-01-01

Superoxide dismutase (SOD) gene expression was investigated to elucidate its role in drought and freezing tolerance in spring and winter wheat (Triticum aestivum). cDNAs encoding chloroplastic Cu/ZnSODs and mitochondrial MnSODs were isolated from wheat. MnSOD and Cu/ZnSOD genes were mapped to the long arms of the homologous group-2 and -7 chromosomes, respectively. Northern blots indicated that MnSOD genes were drought inducible and decreased after rehydration. In contrast, Cu/ZnSOD mRNA was not drought inducible but increased after rehydration. In both spring and winter wheat seedlings exposed to 2°C, MnSOD transcripts attained maximum levels between 7 and 49 d. Transcripts of Cu/ZnSOD mRNA were detected sooner in winter than in spring wheat; however, they disappeared after 21 d of acclimation. Transcripts of both classes of SOD genes increased during natural acclimation in both spring and winter types. Exposure of fully hardened plants to three nonlethal freeze-thaw cycles resulted in Cu/Zn mRNA accumulation; however, MnSOD mRNA levels declined in spring wheat but remained unchanged in winter wheat. The results of the dehydration and freeze-thaw-cycle experiments suggest that winter wheat has evolved a more effective stress-repair mechanism than spring wheat. PMID:10364402

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

PubMed

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

2000-05-11

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

Identification of copper/zinc superoxide dismutase as a novel nitric oxide-regulated gene in rat glomerular mesangial cells and kidneys of endotoxemic rats.

PubMed

Frank, S; Zacharowski, K; Wray, G M; Thiemermann, C; Pfeilschifter, J

1999-05-01

To define the mechanism of nitric oxide (NO) action in the glomerulus, we attempted to identify genes that are regulated by NO in rat glomerular mesangial cells. We identified a Cu/Zn superoxide dismutase (SOD) that was strongly induced in these cells by treatment with S-nitroso-glutathione as a NO-donating agent. Bacterial lipopolysaccharide (LPS) acutely decreased Cu/Zn SOD mRNA levels. The LPS-mediated decrease in Cu/Zn SOD is reversed by endogenously produced NO, as LPS also induced a delayed strong iNOS expression in these cells in vitro, which is accompanied by increased Cu/Zn SOD expression. NO dependency of Cu/Zn SOD mRNA recovery could be demonstrated by inhibition of this process by L-NG-monomethylarginine, an inhibitor of NOS enzymatic activity. To demonstrate the in vivo relevance of our observations, we have chosen LPS-treated rats as a model for induction of a systemic inflammatory response. In these animals, we demonstrate a direct coupling of Cu/Zn SOD expression levels to the presence of NO, as Cu/Zn SOD mRNA levels declined during acute inflammation in the presence of a selective inhibitor of iNOS. We propose that the up-regulation of Cu/Zn SOD by endogenous NO may serve as an adaptive, protective mechanism to prevent the formation of toxic quantities of peroxynitrite in conditions associated with iNOS induction during endotoxic shock.

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

PubMed

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

2006-09-01

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

EXAFS analysis of a human Cu,Zn SOD isoform focused using non-denaturing gel electrophoresis

NASA Astrophysics Data System (ADS)

Chevreux, Sylviane; Solari, Pier Lorenzo; Roudeau, Stéphane; Deves, Guillaume; Alliot, Isabelle; Testemale, Denis; Hazemann, Jean Louis; Ortega, Richard

2009-11-01

Isoelectric point isoforms of a metalloprotein, copper-zinc superoxide dismutase (CuZnSOD), separated on electrophoresis gels were analyzed using X-ray Absorption Spectroscopy. Mutations of this protein are involved in familial cases of amyotrophic lateral sclerosis. The toxicity of mutants could be relied to defects in the metallation state. Our purpose is to establish analytical protocols to study metallation state of protein isoforms such as those from CuZnSOD. We previously highlighted differences in the copper oxidation state between CuZnSOD isoforms using XANES. Here, we present the first results for EXAFS analyses performed at Cu and Zn K-edge on the majoritary expressed isoform of human CuZnSOD separated on electrophoresis gels.

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

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

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

Superoxide-Dismutase Deficient Mutants in Common Beans (Phaseolus vulgaris L.): Genetic Control, Differential Expressions of Isozymes, and Sensitivity to Arsenic

PubMed Central

Talukdar, Dibyendu; Talukdar, Tulika

2013-01-01

Two common bean (Phaseolus vulgaris L.) mutants, sodPv 1 and sodPv 2, exhibiting foliar superoxide dismutase (SOD) activity of only 25% and 40% of their mother control (MC) cv. VL 63 were isolated in EMS-mutagenized (0.15%, 8 h) M2 progeny. Native-PAGE analysis revealed occurrence of Mn SOD, Fe SOD, Cu/Zn SOD I and Cu/Zn SOD II isozymes in MC, while Fe SOD, and Mn SOD were not formed in sodPv 1 and sodPv 2 leaves, respectively. In-gel activity of individual isozymes differed significantly among the parents. SOD deficiency is inherited as recessive mutations, controlled by two different nonallelic loci. Gene expressions using qRT PCR confirmed higher expressions of Cu/Zn SOD transcripts in both mutants and the absence of Fe SOD in sodPv 1 and Mn SOD in sodPv 2. In 50 μM arsenic, Cu/Zn SODs genes were further upregulated but other isoforms downregulated in the two mutants, maintaining SOD activity in its control level. In an F2 double mutants of sodPv 1 × sodPv 2, no Fe SOD, and Mn SOD expressions were detectable, while both Cu/Zn SODs are down-regulated and arsenic-induced leaf necrosis appeared. In contrast to both mutants, ROS-imaging study revealed overaccumulation of both superoxides and H2O2 in leaves of double mutant. PMID:24078924

Crystal structure of bovine Cu,Zn superoxide dismutase at 3 A resolution: chain tracing and metal ligands.

PubMed Central

Richardson, J; Thomas, K A; Rubin, B H; Richardson, D C

1975-01-01

An electron density map at 3 angstrom resolution has been calculated for Cu2+, Zn2+ superoxide dismutase from bovine erythrocytes, and the course of the main chain has been traced. The dominant structural feature is an 8-stranded barrel of antiparallel beta-pleated sheet. There is one very short helical section and two long loops of non-repetitive structure. The Cu and Zn are bound between the loops and one side of the beta barrel and are about 6 Angstrom apart, with a common histidine ligand. The Cu has four histidine ligands in a somewhat distorted square plane, and the Zn has three histidines and an aspartate in approximately tetrahedral arrangement. The two coppers of a dimer are about 34 Angstrom apart. The two subunits have essentially the same conformation and have an extensive contact area that mainly involves hydrophobic side chain interactions. The overall folding pattern of the polypeptide chain is very similar to that of an immunoglobulin domain. Images PMID:1055410

Endotoxin treatment protects rats against ozone-induced lung edema: with evidence for the role of manganese superoxide dismutase

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

Rahman, I.; Massaro, D.

Ozone is a strong oxidizing agent that can cause lung damage and edema. There is evidence that it does so by causing peroxidation of membrane lipids. However, the elevation in lung activity of copper, zinc superoxide dismutase (Cu, ZnSOD), and manganese superoxide dismutase (MnSOD) during exposure to ozone suggests that increased production of superoxide could contribute to lung edema caused by ozone. This latter observation, and preliminary evidence that treatment of rats with endotoxin elevates lung activity of MnSOD without elevation of the activity of Cu, ZnSOD, catalase (CAT), or glutathione peroxidase (GP), led to the present study. We treatedmore » rats with endotoxin, exposed them to different concentrations of ozone, measured lung wet weight to dry weight ratio, thiobarbituric acid-reactive material (TBAR), and assayed lung tissue for Cu, ZnSOD, MnSOD, CAT, and GP activity. Our major findings are, (1) a strongly edemogenic concentration of ozone-lowered MnSOD activity; (2) endotoxin treatment of air-breathing rats did not decrease lipid peroxidation as indicated by the lung concentration of TBAR; (3) induction of increased MnSOD activity in lung by treatment with endotoxin was associated with virtually complete protection against an otherwise edemogenic concentration of ozone, with less lipid peroxidation, and with less loss of weight; and (4) this protection occurred without elevated Cu, ZnSOD, CAT, or GP activity.« less

Flexibility of the Cu,Zn superoxide dismutase structure investigated at 0.57 GPa.

PubMed

Ascone, Isabella; Savino, Carmelinda; Kahn, Richard; Fourme, Roger

2010-06-01

The 2 A resolution crystal structure of bovine erythrocyte Cu,Zn superoxide dismutase (CuZnSOD) has been determined by X-ray diffraction at high pressure (0.57 GPa) and room temperature. At 0.57 GPa the secondary, tertiary and quaternary structures are similar to other previously determined bovine erythrocyte CuZnSOD structures. Nevertheless, pressure has a localized impact on the atomic coordinates of C(alpha) atoms and on side chains. The compression of the crystal and of the protein backbone is anisotropic. This anisotropy is discussed, taking into account intermolecular contacts and protein conformation. Pressure perturbation highlights the more flexible zones in the protein such as the electrostatic loop. At 0.57 GPa, a global shift of the dimetallic sites in both subunits and changes in the oxidation state of Cu were observed. The flexibility of the electrostatic loop may be useful for the interaction of different metal carriers in the copper-uptake process, whereas the flexibility of the metal sites involved in the activity of the protein could contribute to explaining the ubiquitous character of CuZnSODs, which are found in organisms living in very different conditions, including the deep-sea environment. This work illustrates the potential of combining X-ray crystallography with high pressure to promote and stabilize higher energy conformational substates.

Syntheses, structures, and properties of imidazolate-bridged Cu(II)-Cu(II) and Cu(II)-Zn(II) dinuclear complexes of a single macrocyclic ligand with two hydroxyethyl pendants.

PubMed

Li, Dongfeng; Li, Shuan; Yang, Dexi; Yu, Jiuhong; Huang, Jin; Li, Yizhi; Tang, Wenxia

2003-09-22

The imidazolate-bridged homodinuclear Cu(II)-Cu(II) complex, [(CuimCu)L]ClO(4).0.5H(2)O (1), and heterodinuclear Cu(II)-Zn(II) complex, [(CuimZnL(-)(2H))(CuimZnL(-)(H))](ClO(4))(3) (2), of a single macrocyclic ligand with two hydroxyethyl pendants, L (L = 3,6,9,16,19,22-hexaaza-6,19-bis(2-hydroxyethyl)tricyclo[22,2,2,2(11,14)]triaconta-1,11,13,24,27,29-hexaene), have been synthesized as possible models for copper-zinc superoxide dismutase (Cu(2),Zn(2)-SOD). Their crystal structures analyzed by X-ray diffraction methods have shown that the structures of the two complexes are markedly different. Complex 1 crystallizes in the orthorhombic system, containing an imidazolate-bridged dicopper(II) [Cu-im-Cu](3+) core, in which the two copper(II) ions are pentacoordinated by virtue of an N4O environment with a Cu.Cu distance of 5.999(2) A, adopting the geometry of distorted trigonal bipyramid and tetragonal pyramid, respectively. Complex 2 crystallizes in the triclinic system, containing two similar Cu-im-Zn cores in the asymmetric unit, in which both the Cu(II) and Zn(II) ions are pentacoordinated in a distorted trigonal bipyramid geometry, with the Cu.Zn distance of 5.950(1)/5.939(1) A, respectively. Interestingly, the macrocyclic ligand with two arms possesses a chairlike (anti) conformation in complex 1, but a boatlike (syn) conformation in complex 2. Magnetic measurements and ESR spectroscopy of complex 1 have revealed the presence of an antiferromagnetic exchange interaction between the two Cu(II) ions. The ESR spectrum of the Cu(II)-Zn(II) heterodinuclear complex 2 displayed a typical signal for mononuclear trigonal bipyramidal Cu(II) complexes. From pH-dependent ESR and electronic spectroscopic studies, the imidazolate bridges in the two complexes have been found to be stable over broad pH ranges. The cyclic voltammograms of the two complexes have been investigated. Both of the two complexes can catalyze the dismutation of superoxide and show rather high activity.

Molecular Responses to Photooxidative Stress in Pinus sylvestris (L.) (II. Differential Expression of CuZn-Superoxide Dismutases and Glutathione Reductase.

PubMed Central

Karpinski, S.; Wingsle, G.; Karpinska, B.; Hallgren, J. E.

1993-01-01

The influence of photooxidative stress on genes expressing superoxide dismutase (Sod) and glutathione reductase (Gor) was analyzed in needles of top and side shoots of 3-year-old Pinus sylvestris (L.) seedlings. The study was carried out in the field during spring recovery. From mid-April the top shoots of seedlings protruded above the snow and thus were exposed to sunlight, whereas the side shoots were covered with snow until May 4. Needles were sampled from top and side shoots on five different occasions. At the beginning of May the mRNA levels for cytosolic CuZn-Sod were significantly higher in top-shoot needles than in side-shoot needles. Similar results were obtained for chloroplastic CuZn-Sod mRNA. After May 6 we could not detect any significant differences between top- and side-shoot needles for either CuZn-Sod mRNA level. Transcript accumulation for the chloroplastic CuZn-Sod was up to 4-fold higher than for cytosolic CuZn-Sod in both types of shoots. On June 1 minimum transcript levels were observed for both CuZn-SOD isoforms. Protein activity analysis for CuZn-SOD isozymes did not reveal any significant differences between top- and side-shoot needles during the whole period of measurements. The mRNA level for chloroplastic Gor was similar in both types of shoots. However, the total GR activity was significantly higher in top-shoot needles than in side-shoot needles at the beginning of May. The analysis of mRNA accumulation for chloroplastic CuZn-Sod and Gor indicates that transcript levels were at least 5- to 20-fold higher for CuZn-Sod than for chloroplastic Gor. The differential expressions of Sod and Gor genes are discussed in relation to regulation of the enzymic scavenging system during photooxidative stress conditions. PMID:12232032

A novel polymeric ionic liquid-coated magnetic multiwalled carbon nanotubes for the solid-phase extraction of Cu, Zn-superoxide dismutase.

PubMed

Wen, Qian; Wang, Yuzhi; Xu, Kaijia; Li, Na; Zhang, Hongmei; Yang, Qin

2016-10-05

A novel magnetic adsorbent, benzyl groups functionalized imidazolium-based polymeric ionic liquid (PIL)-coated magnetic multiwalled carbon nanotubes (MWCNTs) (m-MWCNTs@PIL), has been successfully synthesized and applied for the extraction of Cu, Zn-superoxide dismutase (Cu, Zn-SOD). The m-MWCNTs@PIL were characterized by X-ray diffraction (XRD), Fourier transform infrared spectrometry (FT-IR), thermal gravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), vibrating sample magnetometer (VSM) and zeta-potential nanoparticles. In this method, the m-MWCNTs@PIL could interact with Cu, Zn-SOD through hydrogen bonding, π-π and electrostatic interactions. The extraction performance of the m-MWCNTs@PIL in the magnetic solid-phase extraction (MSPE) procedure was investigated, coupled with the determination by UV-vis spectrophotometer. Compared with m-MWCNTs@IL and m-MWCNTs, the m-MWCNTs@PIL exhibited the highest extraction capacity of 29.1 mg/g for Cu, Zn-SOD. The adsorbed Cu, Zn-SOD remained high specific activity after being eluted from m-MWCNTs@PIL by 1 moL/L NaCl solution. Besides, the m-MWCNTs@PIL could be easily recycled and successfully employed in the extraction of Cu, Zn-SOD from real samples. Under the optimal conditions, the precision, repeatability and stability of the proposed method were investigated and the RSDs were 0.29%, 1.68% and 0.54%, respectively. Recoveries were in the range of 82.7-102.3%, with the RSD between 3.47% and 5.35%. On the basis of these results, the developed method has great potential in the extraction of Cu, Zn-SOD or other analytes from biological samples. Copyright © 2016 Elsevier B.V. All rights reserved.

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

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

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

1990-03-01

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

Complete Amino Acid Sequence of a Copper/Zinc-Superoxide Dismutase from Ginger Rhizome.

PubMed

Nishiyama, Yuki; Fukamizo, Tamo; Yoneda, Kazunari; Araki, Tomohiro

2017-04-01

Superoxide dismutase (SOD) is an antioxidant enzyme protecting cells from oxidative stress. Ginger (Zingiber officinale) is known for its antioxidant properties, however, there are no data on SODs from ginger rhizomes. In this study, we purified SOD from the rhizome of Z. officinale (Zo-SOD) and determined its complete amino acid sequence using N terminal sequencing, amino acid analysis, and de novo sequencing by tandem mass spectrometry. Zo-SOD consists of 151 amino acids with two signature Cu/Zn-SOD motifs and has high similarity to other plant Cu/Zn-SODs. Multiple sequence alignment showed that Cu/Zn-binding residues and cysteines forming a disulfide bond, which are highly conserved in Cu/Zn-SODs, are also present in Zo-SOD. Phylogenetic analysis revealed that plant Cu/Zn-SODs clustered into distinct chloroplastic, cytoplasmic, and intermediate groups. Among them, only chloroplastic enzymes carried amino acid substitutions in the region functionally important for enzymatic activity, suggesting that chloroplastic SODs may have a function distinct from those of SODs localized in other subcellular compartments. The nucleotide sequence of the Zo-SOD coding region was obtained by reverse-translation, and the gene was synthesized, cloned, and expressed. The recombinant Zo-SOD demonstrated pH stability in the range of 5-10, which is similar to other reported Cu/Zn-SODs, and thermal stability in the range of 10-60 °C, which is higher than that for most plant Cu/Zn-SODs but lower compared to the enzyme from a Z. officinale relative Curcuma aromatica.

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

NASA Technical Reports Server (NTRS)

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

1998-01-01

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

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

USDA-ARS?s Scientific Manuscript database

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

An elevated level of copper zinc superoxide dismutase fails to prevent oxygen induced retinopathy in mice.

PubMed

Klaeger, C; de Sa, L; Klaeger, A J; Carlson, E J; Good, W V; Epstein, C J

1996-05-01

To determine whether a higher level of copper zinc superoxide dismutase (CuZnSOD) can reduce the severity of oxygen induced retinopathy (OIR) in a mouse model. CuZnSOD transgenic mice with a threefold increase in CuZnSOD activity and control non-transgenic mice were exposed to 90% oxygen for 12 hours a day during the first 5 days of life. After oxygen treatment, all mice were reared in room air for 10 days. Another group of transgenic and non-transgenic mice were kept in room air for 15 days and served as control groups for the oxygen effect. At day 15, all mice were killed and perfused with India ink. The retinas were flat mounted on slides and examined with a light microscope. There was a statistically significant increase in the incidence of OIR in mice exposed to high levels of oxygen, whether or not they were transgenic. However, there was no statistically significant difference in the severity of OIR between oxygen treated transgenic and non-transgenic mice. A threefold higher CuZnSOD activity does not protect against OIR in mice. This is an unexpected finding, since oxygen radicals are considered a major factor causing OIR, and increased CuZnSOD activity has reduced oxygen radical induced damage in several neuronal and non-neuronal systems. The possibility of a damaging role for other radicals not affected by CuZnSOD cannot be excluded.

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

PubMed

Jensen, Laran T; Culotta, Valeria Cizewski

2005-12-16

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

Evidence of zinc superoxide formation in the gas phase: comparisons in behaviour between ligated Zn(I/II) and Cu(I/II) with regard to the attachment of O2 or H2O.

PubMed

Cox, Hazel; Norris, Caroline; Wu, Guohua; Guan, Jingang; Hessey, Stephen; Stace, Anthony J

2011-11-14

Singly and doubly charged atomic ions of zinc and copper have been complexed with pyridine and held in an ion trap. Complexes involving Zn(II) and Cu(I) (3d(10)) display a strong tendency to bind with H(2)O, whilst the Zn(I) (3d(10)4s(1)) complexes exhibit a strong preference for the attachment of O(2). DFT calculations show that this latter result can be interpreted as internal oxidation leading to the formation of superoxide complexes, [Zn(II)O(2)(-)](pyridine)(n), in the gas phase. The calculations also show that the oxidation of Zn(I) to form Zn(II)O(2)(-) is promoted by a mixing of the occupied 4s and vacant 4p orbitals on the metal cation, and that this process is facilitated by the presence of the pyridine ligands.

Metallochaperone for Cu,Zn-superoxide dismutase (CCS) protein but not mRNA is higher in organs from copper-deficient mice and rats.

PubMed

Prohaska, Joseph R; Broderius, Margaret; Brokate, Bruce

2003-09-15

Cu,Zn-superoxide dismutase (SOD1) is an abundant metalloenzyme important in scavenging superoxide ions. Cu-deficient rats and mice have lower SOD1 activity and protein, possibly because apo-SOD1 is degraded faster than holo-SOD1. SOD1 interacts with and requires its metallochaperone CCS for donating copper. We produced dietary Cu deficiency in rodents to determine if the reduction in SOD1 was related to the level of its specific metallochaperone CCS. CCS levels determined by immunoblot were 2- to 3-fold higher in liver, heart, kidney, and brain from male Cu-deficient rats and mice under a variety of conditions. CCS was also higher in livers of Cu-deficient dams. Interestingly, CCS levels in brain of Cu-deficient mice were also higher even though SOD1 activity and protein were not altered, suggesting that the rise in CCS is correlated with altered Cu status rather than a direct result of lower SOD1. A DNA probe specific for rat CCS detected a single transcript by Northern blot hybridization with liver RNA. CCS mRNA levels in mouse and rat liver were not altered by dietary treatment. These results suggest a posttranscriptional mechanism for higher CCS protein when Cu is limiting in the cell, perhaps due to slower protein turnover. Elevation in CCS level is one of the most dramatic alterations in Cu binding proteins accompanying Cu deficiency and may be useful to assess Cu status.

Nucleotide sequence of a complementary DNA encoding pea cytosolic copper/zinc superoxide dismutase. [Pisum sativum L

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

White, D.A.; Zilinskas, B.A.

1991-08-01

The authors now report the nucleotide sequence of the cytosolic Cu/Zn SOD cloned from a {lambda}gt11 cDNA library constructed from mRNA extracted from leaves of 7- to 10-d pea seedlings (Pisum sativum L.). The clone was isolated using a 22-base synthetic oligonucleotide complementary to the amino acid sequence CGIIGLQG. This sequence, found at the protein's carboxy terminus, is highly conserved among plant cytosolic Cu/Zn SODs but not chloroplastic Cu/Zn SODs. The 738-base pair sequence contains an open reading frame specifying 152 codons and a predicted M{sub r} of 18,024 D. The deduced amino acid sequence is highly homologous (79-82% identity)more » with the sequences of other known plant cytosolic Cu/Zn SODs but less highly conserved (63-65%) when compared with several chloroplastic Cu/Zn SODs including pea (10).« less

Localization of superoxide dismutases and hydrogen peroxide in legume root nodules.

PubMed

Rubio, Maria C; James, Euan K; Clemente, Maria R; Bucciarelli, Bruna; Fedorova, Maria; Vance, Carroll P; Becana, Manuel

2004-12-01

Superoxide dismutases (SODs) catalyze the dismutation of superoxide radicals to O2 and H2O2 and thus represent a primary line of antioxidant defense in all aerobic organisms. H2O2 is a signal molecule involved in the plant's response to pathogen attack and other stress conditions as well as in nodulation. In this work, we have tested the hypothesis that SODs are a source of H2O2 in indeterminate alfalfa (Medicago sativa) and pea (Pisum sativum) nodules. The transcripts and proteins of the major SODs of nodules were localized by in situ RNA hybridization and immunogold electron microscopy, respectively, whereas H2O2 was localized cytochemically by electron microscopy of cerium-perfused nodule tissue. The transcript and protein of cytosolic CuZnSOD are most abundant in the meristem (I) and invasion (II) zones, interzone II-III, and distal part of the N2-fixing zone (III), and those of MnSOD in zone III, especially in the infected cells. At the subcellular level, CuZnSOD was found in the infection threads, cytosol adjacent to cell walls, and apoplast, whereas MnSOD was in the bacteroids, bacteria within infection threads, and mitochondria. The distinct expression pattern of CuZnSOD and MnSOD suggests specific roles of the enzymes in nodules. Large amounts of H2O2 were found at the same three nodule sites as CuZnSOD but not in association with MnSOD. This colocalization led us to postulate that cytosolic CuZnSOD is a source of H2O2 in nodules. Furthermore, the absence or large reduction of H2O2 in nodule tissue preincubated with enzyme inhibitors (cyanide, azide, diphenyleneiodonium, diethyldithiocarbamate) provides strong support to the hypothesis that at least some of the H2O2 originates by the sequential operation of an NADPH oxidase-like enzyme and CuZnSOD. Results also show that there is abundant H2O2 associated with degrading bacteroids in the senescent zone (IV), which reflects the oxidative stress ensued during nodule senescence.

Copper(II) and zinc(II) dinuclear enzymes model compounds: The nature of the metal ion in the biological function

NASA Astrophysics Data System (ADS)

Ferraresso, L. G.; de Arruda, E. G. R.; de Moraes, T. P. L.; Fazzi, R. B.; Da Costa Ferreira, A. M.; Abbehausen, C.

2017-12-01

First series transition metals are used abundantly by nature to perform catalytic transformations of several substrates. Furthermore, the cooperative activity of two proximal metal ions is common and represents a highly efficient catalytic system in living organisms. In this work three dinuclear μ-phenolate bridged metal complexes were prepared with copper(II) and zinc(II), resulting in a ZnZn, CuCu and CuZn with the ligand 2-ethylaminodimethylamino phenol (saldman) as model compounds of superoxide dismutase (CuCu and CuZn) and metallo-β-lactamases (ZnZn). Metals are coordinated in a μ-phenolate bridged symmetric system. Cu(II) presents a more distorted structure, while zinc is very symmetric. For this reason, [CuCu(saldman)] shows higher water solubility and also higher lability of the bridge. The antioxidant and hydrolytic beta-lactamase-like activity of the complexes were evaluated. The lability of the bridge seems to be important for the antioxidant activity and is suggested to because of [CuCu(saldman)] presents a lower antioxidant capacity than [CuZn(saldman)], which showed to present a more stable bridge in solution. The hydrolytic activity of the bimetallic complexes was assayed using nitrocefin as substrate and showed [ZnZn(saldman)] as a better catalyst than the Cu(II) analog. The series demonstrates the importance of the nature of the metal center for the biological function and how the reactivity of the model complex can be modulated by coordination chemistry.

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

PubMed

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

1992-01-01

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

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

PubMed

Zhu, Jia-Ying; Ze, Sang-Zi; Stanley, David W; Yang, Bin

2014-09-01

Superoxide dismutase (SOD) is an antioxidant enzyme involved in detoxifying reactive oxygen species. In this study, we identified genes encoding the extracellular and intracellular copper-zinc SODs (ecCuZnSOD and icCuZnSOD) and a manganese SOD (MnSOD) in the yellow mealworm beetle, Tenebrio molitor. The cDNAs for ecCuZnSOD, icCuZnSOD, and MnSOD, respectively, encode 24.55, 15.81, and 23.14 kDa polypeptides, which possess structural features typical of other insect SODs. They showed 20-94% identity to other known SOD sequences from Bombyx mori, Musca domestica, Nasonia vitripennis, Pediculus humanus corporis, and Tribolium castaneum. Expression of these genes was analyzed in selected tissues and developmental stages, and following exposure to Escherichia coli and parasitization by Scleroderma guani. We recorded expression of all three SODs in cuticle, fat body, and hemocytes and in the major developmental stages. Relatively higher expressions were detected in late-instar larvae and pupae, compared to other developmental stages. Transcriptional levels were upregulated following bacterial infection. Analysis of pupae parasitized by S. guani revealed that expression of T. molitor SOD genes was significantly induced following parasitization. We infer that these genes act in immune response and in host-parasitoid interactions. © 2014 Wiley Periodicals, Inc.

Exogenous superoxide dismutase may lose its antidotal ability on rice leaves

USDA-ARS?s Scientific Manuscript database

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

High-level expression of a sika deer (Cervus nippon) Cu/Zn superoxide dismutase in Pichia pastoris and its characterization.

PubMed

Li, Ren-Kuan; Fu, Cai-Li; Chen, Ping; Ng, Tzi Bun; Ye, Xiu-Yun

2013-03-01

Production of a sika deer Cu/Zn-SOD was achieved in Pichia pastoris after the reconstituted expression vector pPIC9K was transformed into the strain GS115. By employing Saccharomyces cerevisiae secretion signal peptide (α-factor) under the regulation of the methanol-inducible promoter of the gene of alcohol oxidase 1 (AOX1), sika deer Cu/Zn-SOD with a molecular mass of 16kDa was expressed while recombinant sika deer Cu/Zn-SOD with an activity of 3500U/mL was obtained from a 5L bioreactor. After two successive steps of chromatography on DEAE-650C and Superdex75, recombinant sika deer Cu/Zn-SOD was obtained with 13.8% yield, 14.5-fold purification, and a specific activity of 3447U/mg. Its optimum temperature and optimum pH were 40°C and 7.0, respectively. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

Over-expression of copper/zinc superoxide dismutase in the median preoptic nucleus attenuates chronic angiotensin II-induced hypertension in the rat.

PubMed

Collister, John P; Bellrichard, Mitch; Drebes, Donna; Nahey, David; Tian, Jun; Zimmerman, Matthew C

2014-12-02

The brain senses circulating levels of angiotensin II (AngII) via circumventricular organs, such as the subfornical organ (SFO), and is thought to adjust sympathetic nervous system output accordingly via this neuro-hormonal communication. However, the cellular signaling mechanisms involved in these communications remain to be fully understood. Previous lesion studies of either the SFO, or the downstream median preoptic nucleus (MnPO) have shown a diminution of the hypertensive effects of chronic AngII, without providing a clear explanation as to the intracellular signaling pathway(s) involved. Additional studies have reported that over-expressing copper/zinc superoxide dismutase (CuZnSOD), an intracellular superoxide (O2·-) scavenging enzyme, in the SFO attenuates chronic AngII-induced hypertension. Herein, we tested the hypothesis that overproduction of O2·- in the MnPO is an underlying mechanism in the long-term hypertensive effects of chronic AngII. Adenoviral vectors encoding human CuZnSOD (AdCuZnSOD) or control vector (AdEmpty) were injected directly into the MnPO of rats implanted with aortic telemetric transmitters for recording of arterial pressure. After a 3 day control period of saline infusion, rats were intravenously infused with AngII (10 ng/kg/min) for ten days. Rats over-expressing CuZnSOD (n = 7) in the MnPO had a blood pressure increase of only 6 ± 2 mmHg after ten days of AngII infusion while blood pressure increased 21 ± 4 mmHg in AdEmpty-infected rats (n = 9). These results support the hypothesis that production of O2·- in the MnPO contributes to the development of chronic AngII-dependent hypertension.

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

PubMed Central

Zimak-Piekarczyk, Paulina; Ślesak, Ireneusz

2018-01-01

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

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

PubMed Central

Hérouart, D; Van Montagu, M; Inzé, D

1994-01-01

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

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

PubMed

Hérouart, D; Van Montagu, M; Inzé, D

1994-03-01

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

Effect of high dietary zinc on plasma ceruloplasmin and erythrocyte superoxide dismutase activities in copper-depleted and repleted rats.

PubMed

Panemangalore, M; Bebe, F N

1996-01-01

The effect of moderately high dietary zinc (Zn) on the activities of plasma (PL) ceruloplasmin (CP), and PL and erythrocyte (RBC) copper (Cu), Zn superoxide dismutase (SOD) was determined in weanling rats fed Cu-deficient (DEF; < 1 mg Cu/kg), marginal (MAR; 2 mg Cu/kg), or control (CON; 5 mg Cu/kg) copper diets containing normal or high Zn (HZn; 60 mg/kg) for 4 wk and supplemented with oral Cu (CuS; 5 mg/L) in drinking water for 0, 1, 3, or 7 d. PL Cu decreased (67% compared to CON; p < or = 0.05) in the DEF and increased to control level after 3 d of CuS; increased in the MAR group after 1 d of CuS. HZn reduced overall PL Cu by 27% in all groups, but did not alter the linear increase in PL Cu between 0 and 3 d of Cu S. PL CP activity altered concomitantly with PL Cu levels: The time course of increase in CP activity after 0-3 d of CuS was not influenced by HZn in the diet and CP declined in the DEF group by 92%. There was no correlation between dietary Cu level and PL CP. PL SOD activity decreased by 46% (p < or = .05) in the DEF group, increased to control activity after 1 d of CuS and declined slightly after 7 d; MAR diet did not alter PL SOD. HZn diet increased PL SOD activity in all groups by 150%, reduced activity in the DEF and MAR groups by 65 and 37% and delayed the recovery of PL SOD after CuS. RBC SOD declined in the DEF and MAR groups by 56 and 33% (p < or = 0.05) and did not respond to CuS; HZn diet did not influence RBC SOD activity. These data indicate that moderately high Zn in the diet reduces PL Cu, but not PL CP activity or the recovery of PL Cu or CP activity after oral CuS of Cu-deficient rats, modifies the response of PL SOD to dietary Cu, but does not influence RBC SOD activity.

Properties of purified cytosolic isoenzyme I of Cu,Zn-superoxide dismutase from Nicotiana plumbaginifolia leaves.

PubMed

Ragusa, S; Cambria, M T; Scarpa, M; Di Paolo, M L; Falconi, M; Rigo, A; Cambria, A

2001-11-01

The isoenzyme I of cytosolic Cu,Zn-superoxide dismutase (SOD) from Nicotiana plumbaginifolia (tobacco) leaves has been purified to apparent homogeneity. The relative molecular mass of the native isoenzyme, determined by gel filtration chromatography, is about 33.2 kDa. SDS-polyacrylamide gel electrophoresis shows that the enzyme is composed of two equal subunits of 16.6 kDa The isolectric point, assayed by isoelectric focusing, in the pH range of 3.5-6.5, is 4.3. The enzyme stability was tested at different temperatures, pH, and concentration of inhibitors (KCN and H(2)O(2)). The catalytic constant (k(cat)) was 1.17 +/- 0.14 x 10(9) M(-1) s(-1) at pH 9.9 and 0.1 M ionic strength. The activation energy of the thermal denaturation process is 263 kJ mol(-1). The electrostatic surface potential of the modeled tobacco Cu,Zn-SOD I was calculated showing that the functional spatial network of charges on the protein surface has been maintained, independently of the amino acid substitution around the active sites. Copyright 2001 Academic Press.

Iron, copper, and zinc status: response to supplementation with zinc or zinc and iron in adult females.

PubMed

Yadrick, M K; Kenney, M A; Winterfeldt, E A

1989-01-01

Response of iron, copper, and zinc status to supplementation with Zn or a combination of Zn and Fe was assessed in adult females in a 10-wk study. Group Z received 50 mg Zn/d as Zn gluconate; group F-Z received 50 mg Fe as ferrous sulfate monohydrate in addition to the Zn. For Group Z, serum ferritin, hematocrit, and erythrocyte Cu,Zn-superoxide dismutase (ESOD) were significantly lower (p less than 0.05) after 10 wk supplementation compared with pretreatment levels. Serum Zn increased (p less than 0.01) but no change occurred in serum ceruloplasmin, hemoglobin, or salivary sediment Zn with treatment. For Group F-Z ESOD decreased with treatment as did salivary sediment Zn (p less than 0.05). Serum ferritin and serum Zn increased significantly, but hemoglobin, hematocrit, and ceruloplasmin were not affected by this treatment. Supplementation with Zn poses a risk to Fe and Cu status. Inclusion of Fe with Zn ameliorates the effect on Fe but not on Cu status.

Relationship of ROS accumulation and superoxide dismutase isozymes in developing anther with floret fertility of rice under heat stress.

PubMed

Zhao, Qian; Zhou, Lujian; Liu, Jianchao; Du, Xiaoxia; Asad, Muhammad-Asad-Ullah; Huang, Fudeng; Pan, Gang; Cheng, Fangmin

2018-01-01

High temperature (HT) at meiosis stage is one of most important environment constraint affecting spikelet fertility and rice yield. In this paper, the effects of HT exposure at meiosis stage on the ROS (reactive oxygen species) accumulation, various superoxide dismutase (SOD, EC1.15.1.11) isozymes in developing anther, and its relationship with HT-induced decline in pollen viability and floret fertility were investigated by using four rice cultivars differing in heat tolerance under well-controlled climatic condition. Results showed that HT exposure significantly increased ROS level and malondialdehyde (MDA) content in rice anther, and this occurrence was strongly responsible for the HT-induced decline in pollen viability and harmful effect of HT adversity on floret fertility. However, the increased extent of ROS concentration in rice anther under HT exposure was greatly variable, depending on both the intensity and duration of HT exposure and different rice cultivars used. The SOD and CAT activities of HT-sensitive cultivars decreased more profoundly than those of HT-tolerant cultivars under the same HT regimes. Among various types of SOD enzymes, Cu/Zn-SODa expressed highly in rice anther and responded sensitively to HT exposure, while Cu/Zn-SODb expressed weakly in rice anther and preferentially in rice leaves. HT exposure suppressed the expression of Cu/Zn-SODa in developing anther, which was closely associated with the down-regulated transcripts of cCu/Zn-SOD1 gene. Hence, Cu/Zn-SODa may play a central role in the regulation of total SOD activity and ROS detoxification in rice anther as affected by HT exposure at meiosis stage. Copyright © 2017. Published by Elsevier Masson SAS.

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

EPA Science Inventory

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

Combined proteomic and molecular approaches for cloning and characterization of copper-zinc superoxide dismutase (Cu, Zn-SOD2) from garlic (Allium sativum).

PubMed

Hadji Sfaxi, Imen; Ezzine, Aymen; Coquet, Laurent; Cosette, Pascal; Jouenne, Thierry; Marzouki, M Nejib

2012-09-01

Superoxide dismutases (SODs; EC 1.15.1.1) are key enzymes in the cells protection against oxidant agents. Thus, SODs play a major role in the protection of aerobic organisms against oxygen-mediated damages. Three SOD isoforms were previously identified by zymogram staining from Allium sativum bulbs. The purified Cu, Zn-SOD2 shows an antagonist effect to an anticancer drug and alleviate cytotoxicity inside tumor cells lines B16F0 (mouse melanoma cells) and PAE (porcine aortic endothelial cells). To extend the characterization of Allium SODs and their corresponding genes, a proteomic approach was applied involving two-dimensional gel electrophoresis and LC-MS/MS analyses. From peptide sequence data obtained by mass spectrometry and sequences homologies, primers were defined and a cDNA fragment of 456 bp was amplified by RT-PCR. The cDNA nucleotide sequence analysis revealed an open reading frame coding for 152 residues. The deduced amino acid sequence showed high identity (82-87%) with sequences of Cu, Zn-SODs from other plant species. Molecular analysis was achieved by a protein 3D structural model.

The Cu-Zn superoxide dismutase (SOD1) inhibits ERK phosphorylation by muscarinic receptor modulation in rat pituitary GH3 cells

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

Secondo, Agnese; De Mizio, Mariarosaria; Zirpoli, Laura

The Cu-Zn superoxide dismutase (SOD1) belongs to a family of isoenzymes that are able to dismutate the oxygen superoxide in hydrogen peroxide and molecular oxygen. This enzyme is secreted by many cellular lines and it is also released trough a calcium-dependent depolarization mechanism involving SNARE protein SNAP 25. Using rat pituitary GH3 cells that express muscarinic receptors we found that SOD1 inhibits P-ERK1/2 pathway trough an interaction with muscarinic M1 receptor. This effect is strengthened by oxotremorine, a muscarinic M agonist and partially reverted by pyrenzepine, an antagonist of M1 receptor; moreover this effect is independent from increased intracellular calciummore » concentration induced by SOD1. Finally, P-ERK1/2 inhibition was accompanied by the reduction of GH3 cell proliferation. These data indicate that SOD1 beside the well studied antioxidant properties can be considered as a neuromodulator able to affect mitogen-activated protein kinase in rat pituitary cells trough a M1 muscarinic receptor.« less

Coal-burning endemic fluorosis is associated with reduced activity in antioxidative enzymes and Cu/Zn-SOD gene expression.

PubMed

Wang, Qi; Cui, Kang-ping; Xu, Yuan-yuan; Gao, Yan-ling; Zhao, Jing; Li, Da-sheng; Li, Xiao-lei; Huang, Hou-jin

2014-02-01

To study the effect of fluorine on the oxidative stress in coal-burning fluorosis, we investigated the environmental characteristics of coal-burning endemic fluorosis combined with fluorine content surveillance in air, water, food, briquette, and clay binder samples from Bijie region, Guizhou Province, southwest of China. The activities of antioxidant enzymes including copper/zinc superoxide dismutase (Cu/Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and level of lipid peroxidation such as malondialdehyde (MDA) were measured in serum samples obtained from subjects residing in the Bijie region. Expression of the Cu/Zn-SOD gene was assessed by quantitative reverse transcriptase PCR (qRT-PCR). Our results showed that people suffering from endemic fluorosis (the high and low exposure groups) had much higher MDA level. Their antioxidant enzyme activities and Cu/Zn-SOD gene expression levels were lower when compared to healthy people (the control group). Fluorosis can decrease the activities of antioxidant enzymes, which was associated with exposure level of fluorine. Down-regulation of Cu/Zn-SOD expression may play an important role in the aggravation of oxidative stress in endemic fluorosis.

The effects of copper, manganese and zinc on plant growth and elemental accumulation in the manganese-hyperaccumulator Phytolacca americana.

PubMed

Zhao, Huijun; Wu, Liangqi; Chai, Tuanyao; Zhang, Yuxiu; Tan, Jinjuan; Ma, Shengwen

2012-09-01

Synchrotron radiation X-ray fluorescence (SRXRF) and inductively coupled plasma mass spectrometry were used to estimate major, minor and trace elements in Cu-, Zn- and Mn-treated Phytolacca americana. The effects of the addition of Cu, Zn and Mn on morphological parameters, such as root length, shoot height, and fresh and dry weights of shoots and roots, were also examined. In addition, the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), guaiacol peroxidases (GPX) and catalase (CAT) and the expression of Fe-SOD, Cu/Zn-SOD, metallothionein-2 and glutathione S-transferase (GST) exposed to the highest amounts of Cu, Zn or Mn were detected. Our results confirmed the following: (1) Zn supplementation leads to chlorosis, disturbed elemental homeostasis and decreased concentrations of micro- and macroelements such as Fe, Mg, Mn, Ca and K. Cu competed with Fe, Mn and Zn uptake in plants supplemented with 25 μM Cu. However, no antagonistic interactions took place between Cu, Zn, Mn and Fe uptake in plants supplemented with 100 μM Cu. Mn supplementation at various concentrations had no negative effects on elemental deficits. Mn was co-located with high concentrations of Fe and Zn in mature leaves and the concentrations of macro elements were unchanged. (2) P. americana supplemented with increased concentrations of Zn and Cu exhibited lower biomass production and reduced plant growth. (3) When plants were supplemented with the highest Zn and Cu concentrations, symptoms of toxicity corresponded to decreased SOD or CAT activities and increased APX and GPX activities. However, Mn tolerance corresponded to increased SOD and CAT activities and decreased POD and APX activities. Our study revealed that heavy metals partially exert toxicity by disturbing the nutrient balance and modifying enzyme activities that induce damage in plants. However, P. americana has evolved hyper accumulating mechanisms to maintain elemental balance and redox homeostasis under excess Mn. Copyright © 2012 Elsevier GmbH. All rights reserved.

Models for the mechanism for activating copper-zinc superoxide dismutase in the absence of the CCS Cu chaperone in Arabidopsis.

PubMed

Huang, Chien-Hsun; Kuo, Wen-Yu; Jinn, Tsung-Luo

2012-03-01

Copper-zinc superoxide dismutase (CuZnSOD; CSD) is an important antioxidant enzyme for oxidative stress protection. To date, two activation pathways have been identified in many species. One requiring the CCS, Cu chaperone for SOD, to insert Cu and activate CSD (referred to as CCS-dependent pathway), and the other works independently of CCS (referred to as CCS-independent pathway). In our previous study, we suggest an unidentified factor will work with glutathione (GSH) for CSD activation in the absence of the CCS. Here, two models of the CCS-independent mechanism are proposed. The role of the unidentified factor may work as a scaffold protein, which provides a platform for the CSD protein and Cu-GSH to interact, or as a Cu carrier, which itself can bind Cu and interact with CSD proteins. We also suggest that the CSD protein conformation at C-terminal is important in providing a docking site for unidentified factor to access.

Copper/zinc and copper/selenium ratios, and oxidative stress as biochemical markers in recurrent aphthous stomatitis.

PubMed

Ozturk, Perihan; Belge Kurutas, Ergul; Ataseven, Arzu

2013-10-01

Recurrent aphthous stomatitis (RAS) is a common oral mucosal disorder characterized by recurrent, painful oral aphthae, and oxidative stress presumably contributes to its pathogenesis. The aim of this study is to scrutinize the relationship between oxidative stress and serum trace elements (copper, Cu; zinc, Zn; selenium, Se), and to evaluate the ratios of Cu/Zn and Cu/Se in this disorder. Patients with RAS (n = 33) and age- and sex-matched healthy control subjects (n = 30) were enrolled in this study. Malondialdehyde (MDA) concentrations in plasma and the activities of superoxide dismutase (SOD1; CuZnSOD), glutathione peroxidase (GPx) and catalase (CAT) in erythrocyte were determined as spectrophotometric. Also, the levels of Se, Zn and Cu in serum were determined on flame and furnace atomic absorption spectrophotometer using Zeeman background correction. Oxidative stress was confirmed by the significant elevation in plasma MDA, and by the significant decrease in CAT, SOD1, and GPx (p < 0.05). When compared to controls, Zn and Se levels were significantly lower in patients, whereas Cu levels was higher in RAS patients than those in controls (p < 0.05). In addition, the correlation results of this study were firstly shown that there were significant and positive correlations between Se-CAT, Se-GPx, and Cu-MDA parameters, but negative correlations between Se-Cu, Se-MDA, Cu-CAT, Cu-SOD1 and Cu-GPx parameters in RAS patients. Furthermore, the ratios of Cu/Zn and Cu/Se were significantly higher in the patients than the control subjects (p < 0.05). Our results indicated that lipid peroxidation associated with the imbalance of the trace elements seems to play a crucial role in the pathogenesis of RAS. Furthermore, the serum Cu/Zn and Cu/Se ratios may be used as biochemical markers in these patients. Crown Copyright © 2013. Published by Elsevier GmbH. All rights reserved.

Cardiopulmonary responses of intratracheally instilled tire particles and constituent metal components

USGS Publications Warehouse

Gottipolu, R.R.; Landa, E.R.; Schladweiler, M.C.; McGee, J.K.; Ledbetter, A.D.; Richards, J.H.; Wallenborn, G.J.; Kodavanti, U.P.

2008-01-01

Tire and brake wear particles contain transition metals, and contribute to near-road PM. We hypothesized that acute cardiopulmonary injury from respirable tire particles (TP) will depend on the amount of soluble metals. Respirable fractions of two types of TP (TP1 and TP2) were analyzed for water and acid-leachable metals using ICP-AES. Both TP types contained a variety of transition metals, including zinc (Zn), copper (Cu), aluminum, and iron. Zn and Cu were detected at high levels in water-soluble fractions (TP2 > TP1). Male Wistar Kyoto rats (12-14 wk) were intratracheally instilled, in the first study, with saline, TP1 or TP2 (5 mg/kg), and in the second study, with soluble Zn, Cu (0.5 ??mol/kg), or both. Pulmonary toxicity and cardiac mitochondrial enzymes were analyzed 1 d, 1 wk, or 4 wk later for TP and 4 or 24 h later for metals. Increases in lavage fluid markers of inflammation and injury were observed at d 1 (TP2 > TP1), but these changes reversed by wk 1. No effects on cardiac enzymes were noted with either TP. Exposure of rats to soluble Zn and Cu caused marked pulmonary inflammation and injury but temporal differences were apparent (Cu effects peaked at 4 h and Zn at 24 h). Instillation of Zn, Cu, and Zn+ Cu decreased the activity of cardiac aconitase, isocitrate dehydrogenase, succinate dehydrogenase, cytochrome-c-oxidase and superoxide dismutase suggesting mitochondrial oxidative stress. The observed acute pulmonary toxicity of TP could be due to the presence of water soluble Zn and Cu. At high concentrations these metals may induce cardiac oxidative stress. Copyright ?? Informa Healthcare USA, Inc.

Mechanisms for activating Cu- and Zn-containing superoxide dismutase in the absence of the CCS Cu chaperone.

PubMed

Carroll, Mark C; Girouard, Jody B; Ulloa, Janella L; Subramaniam, Jamuna R; Wong, Phillip C; Valentine, Joan Selverstone; Culotta, Valeria Cizewski

2004-04-20

The Cu- and Zn-containing superoxide dismutase 1 (SOD1) largely obtains Cu in vivo by means of the action of the Cu chaperone CCS. Yet, in the case of mammalian SOD1, a secondary pathway of activation is apparent. Specifically, when human SOD1 is expressed in either yeast or mammalian cells that are null for CCS, the SOD1 enzyme retains a certain degree of activity. This CCS-independent activity is evident with both wild-type and mutant variants of SOD1 that have been associated with familial amyotrophic lateral sclerosis. We demonstrate here that the CCS-independent activation of mammalian SOD1 involves glutathione, particularly the reduced form, or GSH. A role for glutathione in CCS-independent activation was seen with human SOD1 molecules that were expressed in either yeast cells or immortalized fibroblasts. Compared with mammalian SOD1, the Saccharomyces cerevisiae enzyme cannot obtain Cu without CCS in vivo, and this total dependence on CCS involves the presence of dual prolines near the C terminus of the SOD1 polypeptide. Indeed, the insertion of such prolines into human SOD1 rendered this molecule refractory to CCS-independent activation. The possible implications of multiple pathways for SOD1 activation are discussed in the context of SOD1 evolutionary biology and familial amyotrophic lateral sclerosis.

Unique molecular properties of superoxide dismutase from teleost fish skin.

PubMed

Nakano, T; Sato, M; Takeuchi, M

1995-02-27

A unique Cu,Zn-SOD was found and isolated from plaice Paralichthys olivaceus skin. Surprisingly, the properties of purified fish skin SOD were very different from those of SOD from other sources reported so far. The purified SOD was composed of four same subunits of 16 kDa and the molecular weight of the native SOD was found to be around 65 kDa. The dominant amino acids of the SOD were Ser, Thr, Pro and Glu. Above 70 degrees C, thermostability of the SOD was much lower than that of bovine erythrocyte Cu,Zn-SOD.

Effects of dietary zinc on gene expression of antioxidant enzymes and heat shock proteins in hepatopancreas of abalone Haliotis discus hannai.

PubMed

Wu, Chenglong; Zhang, Wenbing; Mai, Kangsen; Xu, Wei; Zhong, Xiaoli

2011-06-01

The expression patterns of different genes encoding antioxidant enzymes and heat shock proteins were investigated, in present study, by real-time quantitative PCR in the hepatopancreas of abalone Haliotis discus hannai fed with different levels of dietary zinc (6.69, 33.8, 710.6 and 3462.5 mg/kg) for 20 weeks. The antioxidant enzymes include Cu/Zn-superoxide dismutase (Cu/Zn-SOD), Mn-superoxide dismutase (Mn-SOD), catalase (CAT), mu-glutathione-s-transferase (mu-GST) and thioredoxin peroxidase (TPx). The results showed that the mRNA expression of these antioxidant enzymes increased and reached the maximum at the dietary zinc level of 33.8 mg/kg, and then dropped progressively. Expression levels of the heat shock proteins (HSP26, HSP70 and HSP90) firstly increased at 33.8 mg/kg dietary Zn level, and reached to the maximum at 710.6 mg/kg, then dropped at 3462.5 mg/kg (p<0.05). Excessive dietary Zn (710.6 and 3462.5 mg/kg) significantly increases the Zn content and significantly decreases the total antioxidant capacity (T-AOC) in hepatopancreas (p<0.05). These findings showed that dietary Zn (33.8 mg/kg) could highly trigger the expression levels of antioxidant enzymes and heat shock proteins, but excessive dietary Zn (710.6 and 3462.5 mg/kg) induces a high oxidative stress in abalone. Copyright © 2011 Elsevier Inc. All rights reserved.

Inflammation protects copper deficient rats from carbon tetrachloride toxicity

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

Yang, F.L.; Joseph, E.; DiSilvestro, R.A.

1991-03-11

Copper deficient rats show low resistance to CCl{sub 4}, possibly due to low liver Cu-Zn superoxide dismutase (SOD) activities. If Cu-Zn SOD is involved, deficiency effects should be aggravated by inflammation which further lowers Cu-Zn SOD activities in deficient rats. On the contrary, inflammation from 0.1 ml turpentine (im, lef) protected these rats from CCl{sub 4} damage assessed by serum activities of 2 liver enzymes. CCl{sub 4} was given ip at 200 {mu}l/kg, 48 h after turpentine, 24 h before sacrifice. Rats were fed low copper for 40 days before CCl{sub 4} challenge. Inflammation also protected rats fed adequate coppermore » from injury, though injury in noninflamed rats was less than with noninflamed deficients. Protection could result from the large increase observed in liver metallothionein, an induction not restricted by copper deficiency. Alternatively, inflammation may block P-450 activation of CCl{sub 4}. Both explanations are currently under investigation, as is the role, if any, of Cu-Zn SOD in resisting CCl{sub 4} injury.« less

Polarizable molecular mechanics studies of Cu(I)/Zn(II) superoxide dismutase: bimetallic binding site and structured waters.

PubMed

Gresh, Nohad; El Hage, Krystel; Perahia, David; Piquemal, Jean-Philip; Berthomieu, Catherine; Berthomieu, Dorothée

2014-11-05

The existence of a network of structured waters in the vicinity of the bimetallic site of Cu/Zn-superoxide dismutase (SOD) has been inferred from high-resolution X-ray crystallography. Long-duration molecular dynamics (MD) simulations could enable to quantify the lifetimes and possible interchanges of these waters between themselves as well as with a ligand diffusing toward the bimetallic site. The presence of several charged or polar ligands makes it necessary to resort to second-generation polarizable potentials. As a first step toward such simulations, we benchmark in this article the accuracy of one such potential, sum of interactions between fragments Ab initio computed (SIBFA), by comparisons with quantum mechanics (QM) computations. We first consider the bimetallic binding site of a Cu/Zn-SOD, in which three histidines and a water molecule are bound to Cu(I) and three histidines and one aspartate are bound to Zn(II). The comparisons are made for different His6 complexes with either one or both cations, and either with or without Asp and water. The total net charges vary from zero to three. We subsequently perform preliminary short-duration MD simulations of 296 waters solvating Cu/Zn-SOD. Six representative geometries are selected and energy-minimized. Single-point SIBFA and QM computations are then performed in parallel on model binding sites extracted from these six structures, each of which totals 301 atoms including the closest 28 waters from the Cu metal site. The ranking of their relative stabilities as given by SIBFA is identical to the QM one, and the relative energy differences by both approaches are fully consistent. In addition, the lowest-energy structure, from SIBFA and QM, has a close overlap with the crystallographic one. The SIBFA calculations enable to quantify the impact of polarization and charge transfer in the ranking of the six structures. Five structural waters, which connect Arg141 and Glu131, are endowed with very high dipole moments (2.7-3.0 Debye), equal and larger than the one computed by SIBFA in ice-like arrangements (2.7 D). Copyright © 2014 Wiley Periodicals, Inc.

Activation of Cu,Zn-superoxide dismutase in the absence of oxygen and the copper chaperone CCS.

PubMed

Leitch, Jeffry M; Jensen, Laran T; Bouldin, Samantha D; Outten, Caryn E; Hart, P John; Culotta, Valeria C

2009-08-14

Eukaryotic Cu,Zn-superoxide dismutases (SOD1s) are generally thought to acquire the essential copper cofactor and intramolecular disulfide bond through the action of the CCS copper chaperone. However, several metazoan SOD1s have been shown to acquire activity in vivo in the absence of CCS, and the Cu,Zn-SOD from Caenorhabditis elegans has evolved complete independence from CCS. To investigate SOD1 activation in the absence of CCS, we compared and contrasted the CCS-independent activation of C. elegans and human SOD1 to the strict CCS-dependent activation of Saccharomyces cerevisiae SOD1. Using a yeast expression system, both pathways were seen to acquire copper derived from cell surface transporters and compete for the same intracellular pool of copper. Like CCS, CCS-independent activation occurs rapidly with a preexisting pool of apo-SOD1 without the need for new protein synthesis. The two pathways, however, strongly diverge when assayed for the SOD1 disulfide. SOD1 molecules that are activated without CCS exhibit disulfide oxidation in vivo without oxygen and under copper-depleted conditions. The strict requirement for copper, oxygen, and CCS in disulfide bond oxidation appears exclusive to yeast SOD1, and we find that a unique proline at position 144 in yeast SOD1 is responsible for this disulfide effect. CCS-dependent and -independent pathways also exhibit differential requirements for molecular oxygen. CCS activation of SOD1 requires oxygen, whereas the CCS-independent pathway is able to activate SOD1s even under anaerobic conditions. In this manner, Cu,Zn-SOD from metazoans may retain activity over a wide range of physiological oxygen tensions.

Nitric oxide activates superoxide dismutase and ascorbate peroxidase to repress the cell death induced by wounding.

PubMed

Lin, Chih-Ching; Jih, Pei-Ju; Lin, Hsin-Hung; Lin, Jeng-Shane; Chang, Ling-Lan; Shen, Yu-Hsing; Jeng, Shih-Tong

2011-10-01

Wounding caused by rain, wind, and pathogen may lead plants to onset defense response. Previous studies indicated that mechanical wounding stimulates plants to generate nitric oxide (NO) and hydrogen peroxide (H(2)O(2)). In this study, the functions of NO and H(2)O(2) after wounding in sweet potato (Ipomoea batatas cv. Tainung 57) was further analyzed. Mechanical wounding damaged cells and resulted in necrosis, but the presence of NO donors or NO scavenger might reduce or enhance the cell death caused by wounding, respectively. The amount of H(2)O(2) induced by wounding was also decreased or increased when plants were incubated with NO donors or NO scavenger, individually. These results indicate that NO may regulate H(2)O(2) generation to affect cell death. NO-induced proteins isolated from two-dimensional electrophoresis were identified to be Copper/Zinc superoxide dismutases (CuZnSODs). The activities of CuZnSODs and ascorbate peroxidase (APX) could be enhanced by NO. In addition, the expression of CuZnSOD and APX was induced by wounding via NO, and their expression was further stimulated by NO through the generation of cGMP. The influx of calcium ions and the activity of NADPH oxidase were also involved in the NO signal transduction pathway inducing APX expression. Collectively, the generation of H(2)O(2) in wounded plants might trigger cell death. Meanwhile, the production of NO induced by wounding stimulated signal transducers including cGMP, calcium ions, and H(2)O(2) to activate CuZnSOD and APX, which further decreased H(2)O(2) level and reduced the cell death caused by wounding.

Enhanced Reactive Oxygen Species Scavenging by Overproduction of Superoxide Dismutase and Catalase Delays Postharvest Physiological Deterioration of Cassava Storage Roots1[C][W][OA

PubMed Central

Xu, Jia; Duan, Xiaoguang; Yang, Jun; Beeching, John R.; Zhang, Peng

2013-01-01

Postharvest physiological deterioration (PPD) of cassava (Manihot esculenta) storage roots is the result of a rapid oxidative burst, which leads to discoloration of the vascular tissues due to the oxidation of phenolic compounds. In this study, coexpression of the reactive oxygen species (ROS)-scavenging enzymes copper/zinc superoxide dismutase (MeCu/ZnSOD) and catalase (MeCAT1) in transgenic cassava was used to explore the intrinsic relationship between ROS scavenging and PPD occurrence. Transgenic cassava plants integrated with the expression cassette p54::MeCu/ZnSOD-35S::MeCAT1 were confirmed by Southern-blot analysis. The expression of MeCu/ZnSOD and MeCAT1 was verified by quantitative reverse transcription-polymerase chain reaction and enzymatic activity analysis both in the leaves and storage roots. Under exposure to the ROS-generating reagent methyl viologen or to hydrogen peroxide (H2O2), the transgenic plants showed higher enzymatic activities of SOD and CAT than the wild-type plants. Levels of malondialdehyde, chlorophyll degradation, lipid peroxidation, and H2O2 accumulation were dramatically reduced in the transgenic lines compared with the wild type. After harvest, the storage roots of transgenic cassava lines show a delay in their PPD response of at least 10 d, accompanied by less mitochondrial oxidation and H2O2 accumulation, compared with those of the wild type. We hypothesize that this is due to the combined ectopic expression of Cu/ZnSOD and CAT leading to an improved synergistic ROS-scavenging capacity of the roots. Our study not only sheds light on the mechanism of the PPD process but also develops an effective approach for delaying the occurrence of PPD in cassava. PMID:23344905

Enhanced reactive oxygen species scavenging by overproduction of superoxide dismutase and catalase delays postharvest physiological deterioration of cassava storage roots.

PubMed

Xu, Jia; Duan, Xiaoguang; Yang, Jun; Beeching, John R; Zhang, Peng

2013-03-01

Postharvest physiological deterioration (PPD) of cassava (Manihot esculenta) storage roots is the result of a rapid oxidative burst, which leads to discoloration of the vascular tissues due to the oxidation of phenolic compounds. In this study, coexpression of the reactive oxygen species (ROS)-scavenging enzymes copper/zinc superoxide dismutase (MeCu/ZnSOD) and catalase (MeCAT1) in transgenic cassava was used to explore the intrinsic relationship between ROS scavenging and PPD occurrence. Transgenic cassava plants integrated with the expression cassette p54::MeCu/ZnSOD-35S::MeCAT1 were confirmed by Southern-blot analysis. The expression of MeCu/ZnSOD and MeCAT1 was verified by quantitative reverse transcription-polymerase chain reaction and enzymatic activity analysis both in the leaves and storage roots. Under exposure to the ROS-generating reagent methyl viologen or to hydrogen peroxide (H2O2), the transgenic plants showed higher enzymatic activities of SOD and CAT than the wild-type plants. Levels of malondialdehyde, chlorophyll degradation, lipid peroxidation, and H2O2 accumulation were dramatically reduced in the transgenic lines compared with the wild type. After harvest, the storage roots of transgenic cassava lines show a delay in their PPD response of at least 10 d, accompanied by less mitochondrial oxidation and H2O2 accumulation, compared with those of the wild type. We hypothesize that this is due to the combined ectopic expression of Cu/ZnSOD and CAT leading to an improved synergistic ROS-scavenging capacity of the roots. Our study not only sheds light on the mechanism of the PPD process but also develops an effective approach for delaying the occurrence of PPD in cassava.

Time- and dose-dependent differential regulation of copper-zinc superoxide dismutase and manganese superoxide dismutase enzymatic activity and mRNA level by vitamin E in rat blood cells.

PubMed

Hajiani, Maliheh; Razi, Farideh; Golestani, Aboualfazl; Frouzandeh, Mehdi; Owji, Ali Akbar; Khaghani, Shahnaz; Ghannadian, Naghmeh; Shariftabrizi, Ahmad; Pasalar, Parvin

2012-01-01

Vitamin E is the most important lipid-soluble antioxidant. Recently, it has been proposed as a gene regulator, and its gene modulation effects have been observed at different levels of gene expression and cell signaling. This study was performed to investigate the effects of vitamin E on the activity and expression of the most important endogenous antioxidant enzyme, superoxide dismutase (SOD), in rat plasma. Twenty-eight male Sprauge-Dawley rats were divided into four groups: control group and three dosing groups. The control group received the vehicle (liquid paraffin), and the dosing groups received twice-weekly intraperitoneal injections of 10, 30, and 100 mg/kg of vitamin E ((±)-α-Tocopherol) for 6 weeks. Quantitative real-time reverse transcription-polymerase chain reaction and enzyme assays were used to assess the levels of Cu/Zn-SOD and Mn-SOD mRNA and enzyme activity levels in blood cells at 0, 2, 4, and 6 weeks following vitamin E administration. Catalase enzyme activity and total antioxidant capacity were also assessed in plasma at the same time intervals. Mn-SOD activity was significantly increased in the 100 and 30 mg/kg dosing groups after 4 and 6 weeks, with corresponding significant increase in their mRNA levels. Cu/Zn-SOD activity was not significantly changed in response to vitamin E administration at any time points, whereas Cu/Zn-SOD mRNA levels were significantly increased after longer time points with high doses (30 and 100 mg/kg) of vitamin E. Catalase enzyme activity was transiently but significantly increased after 4 weeks of vitamin E treatment in 30 and 100 mg/kg dosing groups. Total antioxidant status was significantly increased after 4 and 6 weeks in the 100 mg/kg dosing group. Only the chronic administration of higher doses of alpha-tocopherol is associated with the increased activity and expression of Mn-SOD in rats. Cu/Zn-SOD activity and expression does not dramatically change in response to vitamin E.

Blood antioxidant enzymes as markers of exposure or effect in coal miners.

PubMed Central

Perrin-Nadif, R; Auburtin, G; Dusch, M; Porcher, J M; Mur, J M

1996-01-01

OBJECTIVE--To investigate if blood Cu++/Zn++ superoxide dismutase, glutathione peroxidase, catalase, and total plasma antioxidant activities could be markers of biological activity resulting from exposure to respirable coal mine dust in active miners, and of pneumoconiosis in retired miners. METHODS--Blood samples were randomly obtained from active surface workers (n = 30) and underground miners (n = 34), and from retired miners without (n = 21), and with (n = 33) pneumoconiosis. Antioxidant enzyme activities and total plasma antioxidants were measured in erythrocytes and plasma. Non-parametric tests were completed by analyses of covariance to compare antioxidants between groups, taking into account potential confounding factors (age, smoking history (pack-years)). RESULTS--Erythrocyte Cu++/Zn++ superoxide dismutase activity was significantly higher in the group of underground miners than the group of surface workers. The differences in total plasma antioxidants and plasma glutathione peroxidase activity between both groups were related to age. Glutathione peroxidase activity increased in the plasma of retired miners with pneumoconiosis, compared with retired miners without pneumoconiosis. No differences were found either in erythrocyte antioxidant enzyme activities or in total plasma antioxidants between the groups of retired miners without and with pneumoconiosis. CONCLUSIONS--In this study, erythrocyte Cu++/Zn++ superoxide dismutase activity may be considered as a marker of effect of respirable coal mine dust in exposed workers. This result is in agreement with the hypothesis that reactive oxygen species are involved in cell injury induced by coal mine dust, and may be predictive of the degree of inflammation and pneumoconiosis induced by coal mine dust. The increase in glutathione peroxidase activity in the plasma of retired miners with pneumoconiosis may be the result of a response to the increasing hydrogen peroxide (H2O2) production due to the disease process. PMID:8563856

Zn II(atsm) is protective in amyotrophic lateral sclerosis model mice via a copper delivery mechanism.

PubMed

McAllum, Erin J; Roberts, Blaine R; Hickey, James L; Dang, Theresa N; Grubman, Alexandra; Donnelly, Paul S; Liddell, Jeffrey R; White, Anthony R; Crouch, Peter J

2015-09-01

Mutations in the metalloprotein Cu,Zn-superoxide dismutase (SOD1) cause approximately 20% of familial cases of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease for which effective therapeutics do not yet exist. Transgenic rodent models based on over-expression of mutant SOD1 have been developed and these have provided opportunity to test new therapeutic strategies and to study the mechanisms of mutant SOD1 toxicity. Although the mechanisms of mutant SOD1 toxicity are yet to be fully elucidated, incorrect or incomplete metallation of SOD1 confers abnormal folding, aggregation and biochemical properties, and improving the metallation state of SOD1 provides a viable therapeutic option. The therapeutic effects of delivering copper (Cu) to mutant SOD1 have been demonstrated recently. The aim of the current study was to determine if delivery of zinc (Zn) to SOD1 was also therapeutic. To investigate this, SOD1G37R mice were treated with the metal complex diacetyl-bis(4-methylthiosemicarbazonato)zinc(II) [Zn(II)(atsm)]. Treatment resulted in an improvement in locomotor function and survival of the mice. However, biochemical analysis of spinal cord tissue collected from the mice revealed that the treatment did not increase overall Zn levels in the spinal cord nor the Zn content of SOD1. In contrast, overall levels of Cu in the spinal cord were elevated in the Zn(II)(atsm)-treated SOD1G37R mice and the Cu content of SOD1 was also elevated. Further experiments demonstrated transmetallation of Zn(II)(atsm) in the presence of Cu to form the Cu-analogue Cu(II)(atsm), indicating that the observed therapeutic effects for Zn(II)(atsm) in SOD1G37R mice may in fact be due to in vivo transmetallation and subsequent delivery of Cu. Copyright © 2015. Published by Elsevier Inc.

Purification of Cu/Zn superoxide dismutase from Piper betle leaf and its characterization in the oral cavity.

PubMed

Liu, Yu-Ching; Lee, Miau-Rong; Chen, Chao-Jung; Lin, Yung-Chang; Ho, Heng-Chien

2015-03-04

The aim of this study was to purify protein(s) from Piper betle leaf for identification and further characterization. A functionally unknown protein was purified to apparent homogeneity with a molecular mass of 15.7 kDa and identified as Cu/Zn superoxide dismutase (SOD). The purified SOD appeared to be monomeric and converted to its dimeric form with increased enzymatic activity in betel nut oral extract. This irreversible conversion was mainly induced by slaked lime, resulting from the increase in pH of the oral cavity. Oral extract from chewing areca nut alone also induced SOD dimerization due to the presence of arginine. The enhanced activity of the SOD dimer was responsible for the continuous production of hydrogen peroxide in the oral cavity. Thus, SOD may contribute to oral carcinogenesis through the continuous formation of hydrogen peroxide in the oral cavity, in spite of its protective role against cancer in vivo.

Gene Disruption in Scedosporium aurantiacum: Proof of Concept with the Disruption of SODC Gene Encoding a Cytosolic Cu,Zn-Superoxide Dismutase.

PubMed

Pateau, Victoire; Razafimandimby, Bienvenue; Vandeputte, Patrick; Thornton, Christopher R; Guillemette, Thomas; Bouchara, Jean-Philippe; Giraud, Sandrine

2018-02-01

Scedosporium species are opportunistic pathogens responsible for a large variety of infections in humans. An increasing occurrence was observed in patients with underlying conditions such as immunosuppression or cystic fibrosis. Indeed, the genus Scedosporium ranks the second among the filamentous fungi colonizing the respiratory tracts of the CF patients. To date, there is very scarce information on the pathogenic mechanisms, at least in part because of the limited genetic tools available. In the present study, we successfully developed an efficient transformation and targeted gene disruption approach on the species Scedosporium aurantiacum. The disruption cassette was constructed using double-joint PCR procedure, and resistance to hygromycin B as the selection marker. This proof of concept was performed on the functional gene SODC encoding the Cu,Zn-superoxide dismutase. Disruption of the SODC gene improved susceptibility of the fungus to oxidative stress. This technical advance should open new research areas and help to better understand the biology of Scedosporium species.

Folding of Cu/Zn superoxide dismutase suggests structural hotspots for gain of neurotoxic function in ALS: Parallels to precursors in amyloid disease

PubMed Central

Nordlund, Anna; Oliveberg, Mikael

2006-01-01

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease linked to misfolding of the ubiquitous enzyme Cu/Zn superoxide dismutase (SOD). In contrast to other protein-misfolding disorders with similar neuropathogenesis, ALS is not always associated with the in vivo deposition of protein aggregates. Thus, under the assumption that all protein-misfolding disorders share at primary level a similar disease mechanism, ALS constitutes an interesting disease model for identifying the yet-mysterious precursor states from which the cytotoxic pathway emerges. In this study, we have mapped out the conformational repertoire of the apoSOD monomer through analysis of its folding behavior. The results allow us to target the regions of the SOD structure that are most susceptible to unfolding locally under physiological conditions, leading to the exposure of structurally promiscuous interfaces that are normally hidden in the protein’s interior. The structure of this putative ALS precursor is strikingly similar to those implicated in amyloid disease. PMID:16798882

The Megavirus Chilensis Cu,Zn-Superoxide Dismutase: the First Viral Structure of a Typical Cellular Copper Chaperone-Independent Hyperstable Dimeric Enzyme

PubMed Central

Lartigue, Audrey; Burlat, Bénédicte; Coutard, Bruno; Chaspoul, Florence; Claverie, Jean-Michel

2014-01-01

ABSTRACT Giant viruses able to replicate in Acanthamoeba castellanii penetrate their host through phagocytosis. After capsid opening, a fusion between the internal membranes of the virion and the phagocytic vacuole triggers the transfer in the cytoplasm of the viral DNA together with the DNA repair enzymes and the transcription machinery present in the particles. In addition, the proteome analysis of purified mimivirus virions revealed the presence of many enzymes meant to resist oxidative stress and conserved in the Mimiviridae. Megavirus chilensis encodes a predicted copper, zinc superoxide dismutase (Cu,Zn-SOD), an enzyme known to detoxify reactive oxygen species released in the course of host defense reactions. While it was thought that the metal ions are required for the formation of the active-site lid and dimer stabilization, megavirus chilensis SOD forms a very stable metal-free dimer. We used electron paramagnetic resonance (EPR) analysis and activity measurements to show that the supplementation of the bacterial culture with copper and zinc during the recombinant expression of Mg277 is sufficient to restore a fully active holoenzyme. These results demonstrate that the viral enzyme's activation is independent of a chaperone both for disulfide bridge formation and for copper incorporation and suggest that its assembly may not be as regulated as that of its cellular counterparts. A SOD protein is encoded by a variety of DNA viruses but is absent from mimivirus. As in poxviruses, the enzyme might be dispensable when the virus infects Acanthamoeba cells but may allow megavirus chilensis to infect a broad range of eukaryotic hosts. IMPORTANCE Mimiviridae are giant viruses encoding more than 1,000 proteins. The virion particles are loaded with proteins used by the virus to resist the vacuole's oxidative stress. The megavirus chilensis virion contains a predicted copper, zinc superoxide dismutase (Cu,Zn-SOD). The corresponding gene is present in some megavirus chilensis relatives but is absent from mimivirus. This first crystallographic structure of a viral Cu,Zn-SOD highlights the features that it has in common with and its differences from cellular SODs. It corresponds to a very stable dimer of the apo form of the enzyme. We demonstrate that upon supplementation of the growth medium with Cu and Zn, the recombinant protein is fully active, suggesting that the virus's SOD activation is independent of a copper chaperone for SOD generally used by eukaryotic SODs. PMID:25355875

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

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

Tabatabai, L.B.

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

The effect of nano-TiO2 photocatalysis on the antioxidant activities of Cu, Zn-SOD at physiological pH.

PubMed

Zheng, Wen; Zou, Hai-Feng; Lv, Shao-Wu; Lin, Yan-Hong; Wang, Min; Yan, Fei; Sheng, Ye; Song, Yan-Hua; Chen, Jie; Zheng, Ke-Yan

2017-09-01

Security issues of nanoparticles on biological toxicity and potential environmental risk have attracted more and more attention with the rapid development and wide applications of nanotechnology. In this work, we explored the effect and probable mechanism of nano-TiO 2 on antioxidant activity of copper, zinc superoxide dismutase (Cu, Zn-SOD) under natural light and mixed light at physiological pH. Nano-TiO 2 was prepared by sol-hydrothermal method, and then characterized by X-ray Diffraction (XRD) and Transmission electron micrographs (TEM). The Cu, Zn-SOD was purified by sephadex G75 chromatography and qualitatively analyzed by sodium dodecyl sulfate polypropylene amide gel electrophoresis (SDS-PAGE). The effect and mechanism were elucidated base on Fourier Transform Infrared Spectrometer (FT-IR), Circular Dichroism (CD), zeta potential, and electron spin resonance (ESR) methods. Accompanying the results of FT-IR, CD and zeta potential, it could be concluded that nano-TiO 2 had no effect on the antioxidant activity of Cu, Zn-SOD by comparing the relative activity under natural light at physiological pH. But the relative activity of Cu, Zn-SOD significantly decreased along with the increase of nano-TiO 2 concentration under the mixed light. The results of ESR showed the cause of this phenomenon was the Cu(II) in the active site of Cu, Zn-SOD was reduced to Cu(I) by H 2 O 2 and decreased the content of active Cu, Zn-SOD. The reduction can be inhibited by catalase. Excess O 2 ·- produced by nano-TiO 2 photocatalysis under mixed light accumulated a mass of H 2 O 2 through disproportionation reaction in this experimental condition. The results show that nano-TiO 2 cannot affect the antioxidant activity of Cu, Zn-SOD in daily life. The study on the effect of nano-TiO 2 on Cu, Zn-SOD will provide a valid theory support for biological safety and the toxicological effect mechanism of nanomaterials on enzyme. Copyright © 2017 Elsevier B.V. All rights reserved.

Neuroprotective Effects and Mechanisms of Curcumin-Cu(II) and -Zn(II) Complexes Systems and Their Pharmacological Implications.

PubMed

Yan, Fa-Shun; Sun, Jian-Long; Xie, Wen-Hai; Shen, Liang; Ji, Hong-Fang

2017-12-28

Alzheimer's disease (AD) is the main form of dementia and has a steadily increasing prevalence. As both oxidative stress and metal homeostasis are involved in the pathogenesis of AD, it would be interesting to develop a dual function agent, targeting the two factors. Curcumin, a natural compound isolated from the rhizome of Curcuma longa , is an antioxidant and can also chelate metal ions. Whether the complexes of curcumin with metal ions possess neuroprotective effects has not been evaluated. Therefore, the present study was designed to investigate the protective effects of the complexes of curcumin with Cu(II) or Zn(II) on hydrogen peroxide (H₂O₂)-induced injury and the underlying molecular mechanisms. The use of rat pheochromocytoma (PC12) cells, a widely used neuronal cell model system, was adopted. It was revealed that curcumin-Cu(II) complexes systems possessed enhanced O₂ ·- -scavenging activities compared to unchelated curcumin. In comparison with unchelated curcumin, the protective effects of curcumin-Cu(II) complexes systems were stronger than curcumin-Zn(II) system. Curcumin-Cu(II) or -Zn(II) complexes systems significantly enhanced the superoxide dismutase, catalase, and glutathione peroxidase activities and attenuated the increase of malondialdehyde levels and caspase-3 and caspase-9 activities, in a dose-dependent manner. The curcumin-Cu(II) complex system with a 2:1 ratio exhibited the most significant effect. Further mechanistic study demonstrated that curcumin-Cu(II) or -Zn(II) complexes systems inhibited cell apoptosis via downregulating the nuclear factor κB (NF-κB) pathway and upregulating Bcl-2/Bax pathway. In summary, the present study found that curcumin-Cu(II) or -Zn(II) complexes systems, especially the former, possess significant neuroprotective effects, which indicates the potential advantage of curcumin as a promising agent against AD and deserves further study.

Random T-DNA mutagenesis identifies a Cu-Zn-superoxide dismutase gene as a virulence factor of Sclerotinia sclerotiorum

USDA-ARS?s Scientific Manuscript database

Agrobacterium-mediated transformation (AMT) was used to identify potential virulence factors in Sclerotinia sclerotiorum. Screening AMT transformants identified two mutants showing significantly reduced virulence. The mutants showed similar growth rate, colony morphology, and sclerotial and oxalate ...

Structural, functional and immunogenic insights on Cu,Zn superoxide dismutase pathogenic virulence factors from Neisseria meningitidis and Brucella abortus

DOE PAGES

Pratt, Ashley J.; DiDonato, Michael; Shin, David S.; ...

2015-10-12

Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and health consequences. Superoxide dismutases are master regulators of reactive oxygen, general pathogenicity factors and therefore therapeutic targets. Cu,Zn superoxide dismutases (SODs) localized to the periplasm promote survival by detoxifying superoxide radicals generated by major host antimicrobial immune responses. We discovered that passive immunization with an antibody directed at N. meningitidis SOD (NmSOD) was protective in a mouse infection model. To define the relevant atomicmore » details and solution assembly states of this important virulence factor, we report high-resolution and X-ray scattering analyses of NmSOD and SOD from B. abortus (BaSOD). The NmSOD structures revealed an auxiliary tetrahedral Cu-binding site bridging the dimer interface; mutational analyses suggested that this metal site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses informed us about electrostatic substrate guidance, dimer assembly and an exposed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure provided insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes and suggest general targets for anti-bacterial immune responses. The identified functional contributions, motifs, and targets distinguishing bacterial and eukaryotic SOD assemblies presented here provide a foundation for efforts to develop SOD-specific inhibitors or vaccines against these harmful pathogens. IMPORTANCE By protecting microbes against reactive oxygen insults, Cu,Zn superoxide dismutases (SODs) aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific differences relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of Neisseria meningitidis and Brucella abortus SODs, we used X-ray structures, enzymology, modeling and murine infection experiments. We identified virulence determinants common to both homologs, assembly differences and a unique metal reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and basis for SOD-specific drugs and extension of immunogen design to target two important pathogens that continue to pose global health threats.« less

Structural, functional and immunogenic insights on Cu,Zn superoxide dismutase pathogenic virulence factors from Neisseria meningitidis and Brucella abortus

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

Pratt, Ashley J.; DiDonato, Michael; Shin, David S.

Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and health consequences. Superoxide dismutases are master regulators of reactive oxygen, general pathogenicity factors and therefore therapeutic targets. Cu,Zn superoxide dismutases (SODs) localized to the periplasm promote survival by detoxifying superoxide radicals generated by major host antimicrobial immune responses. We discovered that passive immunization with an antibody directed at N. meningitidis SOD (NmSOD) was protective in a mouse infection model. To define the relevant atomicmore » details and solution assembly states of this important virulence factor, we report high-resolution and X-ray scattering analyses of NmSOD and SOD from B. abortus (BaSOD). The NmSOD structures revealed an auxiliary tetrahedral Cu-binding site bridging the dimer interface; mutational analyses suggested that this metal site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses informed us about electrostatic substrate guidance, dimer assembly and an exposed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure provided insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes and suggest general targets for anti-bacterial immune responses. The identified functional contributions, motifs, and targets distinguishing bacterial and eukaryotic SOD assemblies presented here provide a foundation for efforts to develop SOD-specific inhibitors or vaccines against these harmful pathogens. IMPORTANCE By protecting microbes against reactive oxygen insults, Cu,Zn superoxide dismutases (SODs) aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific differences relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of Neisseria meningitidis and Brucella abortus SODs, we used X-ray structures, enzymology, modeling and murine infection experiments. We identified virulence determinants common to both homologs, assembly differences and a unique metal reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and basis for SOD-specific drugs and extension of immunogen design to target two important pathogens that continue to pose global health threats.« less

Exploration of Molecular Factors Impairing Superoxide Dismutase Isoforms Activity in Human Senile Cataractous Lenses

PubMed Central

Rajkumar, Sankaranarayanan; Vasavada, Abhay R.; Praveen, Mamidipudi R.; Ananthan, Rajendran; Reddy, Geereddy B.; Tripathi, Harsha; Ganatra, Darshini A.; Arora, Anshul I.; Patel, Alpesh R.

2013-01-01

Purpose. To explore different molecular factors impairing the activities of superoxide dismutase (SOD) isoforms in senile cataractous lenses. Methods. Enzyme activity of SOD isoforms, levels of their corresponding cofactors copper (Cu), manganese (Mn), zinc (Zn), and expression of mRNA transcripts and proteins were determined in the lenses of human subjects with and without cataract. DNA from lens epithelium (LE) and peripheral blood was isolated. Polymerase chain reaction–single strand conformation polymorphism (PCR-SSCP) followed by sequencing was carried out to screen somatic mutations. The impact of intronic insertion/deletion (INDEL) variations on the splicing process and on the resultant transcript was evaluated. Genotyping of IVS4+42delG polymorphism of SOD1 gene was done by PCR–restriction fragment length polymorphism (RFLP). Results. A significant decrease in Cu/Zn- and Mn-SOD activity (P < 0.001) and in Cu/Zn-SOD transcript (P < 0.001) and its protein (P < 0.05) were found in cataractous lenses. No significant change in the level of copper (P = 0.36) and an increase in the level of manganese (P = 0.01) and zinc (P = 0.02) were observed in cataractous lenses. A significant positive correlation between the level of Cu/Zn-SOD activity and the levels of Cu (P = 0.003) and Zn (P = 0.005) was found in the cataractous lenses. DNA sequencing revealed three intronic INDEL variations in exon4 of SOD1 gene. Splice-junction analysis showed the potential of IVS4+42delG in creating a new cryptic acceptor site. If it is involved in alternate splicing, it could result in generation of SOD1 mRNA transcripts lacking exon4 region. Transcript analysis revealed the presence of complete SOD1 mRNA transcripts. Genotyping revealed the presence of IVS4+42delG polymorphism in all subjects. Conclusions. The decrease in the activity of SOD1 isoform in cataractous lenses was associated with the decreased level of mRNA transcripts and their protein expression and was not associated with either modulation in the level of enzyme cofactors or with INDEL variations. PMID:23970468

Adaptation to chronic MG132 reduces oxidative toxicity by a CuZnSOD-dependent mechanism

PubMed Central

Leak, Rehana K.; Zigmond, Michael J.; Liou, Anthony K. F.

2010-01-01

To study whether and how cells adapt to chronic cellular stress, we exposed PC12 cells to the proteasome inhibitor MG132 (0.1 μM) for 2 weeks and longer. This treatment reduced chymotrypsin-like proteasome activity by 47% and was associated with protection against both 6-hydroxydopamine (6-OHDA, 100 μM) and higher dose MG132 (40 μM). Protection developed slowly over the course of the first 2 weeks of exposure and was chronic thereafter. There was no change in total glutathione levels after MG132. Buthionine sulfoximine (100 μM) reduced glutathione levels by 60%, but exacerbated 6-OHDA toxicity to the same extent in both MG132-treated and control cells and failed to reduce MG132-induced protection. Chronic MG132 resulted in elevated antioxidant proteins CuZn superoxide dismutase (SOD, +55%), MnSOD (+21%), and catalase (+15%), as well as chaperone heat shock protein 70 (+42%). Examination of SOD enzyme activity revealed higher levels of CuZnSOD (+40%), with no change in MnSOD. We further assessed the mechanism of protection by reducing CuZnSOD levels with two independent siRNA sequences, both of which successfully attenuated protection against 6-OHDA. Previous reports suggested that artificial overexpression of CuZnSOD in dopaminergic cells is protective. Our data complement such observations, revealing that dopaminergic cells are also able to use endogenous CuZnSOD in self-defensive adaptations to chronic stress, and that they can even do so in the face of extensive glutathione loss. PMID:18466318

Random T-DNA mutagenesis identifies a Cu-Zn-superoxide dismutase gene as a virulence factor of Sclerotinia sclerotiorum

USDA-ARS?s Scientific Manuscript database

The Ascomycetous fungus Sclerotinia sclerotiorum is a devastating pathogen capable of infecting more than 400 plant species including many economically important crops. In order to gain a better mechanistic understanding of its non-specific host-pathogen interactions, random mutagenesis through Agro...

Structural, functional and immunogenic insights on Cu,Zn Superoxide Dismutase pathogenic virulence factors from Neisseria meningitidis and Brucella abortus

USDA-ARS?s Scientific Manuscript database

Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and he...

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

PubMed

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

2018-03-30

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

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

PubMed

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

2017-01-01

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

The Role of Oxidative Stress in the Clinical Manifestations of Childhood Asthma.

PubMed

Topic, Aleksandra; Francuski, Djordje; Nikolic, Aleksandra; Milosevic, Katarina; Jovicic, Snezana; Markovic, Bojan; Djukic, Mirjana; Radojkovic, Dragica

2017-08-01

The significance of oxidative stress in pathogenesis of childhood asthma was recognized, but its role in the clinical manifestations of disease is still unclear. The study was conducted in 96 asthmatic children. The urinary biomarker of oxidative stress, 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG/creatinine) was determined by using HPLC-MS/MS. ELISA was performed to measure myeloperoxidase (MPO) and Cu,Zn- superoxide dismutase (Cu,Zn-SOD) in serum. Logistic regression analysis revealed that female gender, tobacco smoke exposure, and increased 8-oxodG/creatinine were associated with risk for intermittent asthma, while the positive allergy test and increased Cu,Zn-SOD were associated with eczema in asthmatic children. Higher MPO (p = 0.033), and percent of granulocytes (p = 0.030) were found in severe persistent asthma in comparison to intermittent or mild persistent asthma. The main findings that TSE-induced oxidative stress is a risk for intermittent asthma and eczema may be clinically significant for the disease prevention and therapeutic improvements.

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

PubMed Central

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

2011-01-01

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

Biochemical analysis of reactive oxygen species production and antioxidative responses in unripe avocado (Persea americana Mill var Hass) fruits in response to wounding.

PubMed

Castro-Mercado, E; Martinez-Diaz, Y; Roman-Tehandon, N; Garcia-Pineda, E

2009-03-01

We analyzed the production of reactive oxygen species (ROS) and of detoxifying enzymes and enzymes of the ascorbate (ASC) acid cycle in avocado fruit (Pesea Americana Mill cv Hass) in response to wounding. The levels of superoxide anion (O(2-), hydroxyl radicals (OH.) and hydrogen peroxide (H(2)O(2)) increased at 15 min and 2 and 15 h post-wounding. Peroxidase (POD) activity had increased to high levels 24 h after wounding; in contrast, catalase and superoxide dismutase (SOD) levels hat decreased significantly at 24 h post-treatment. Basic POD was the major POD form induced, and the levels of at least three apoplastic POD isozymes -increased following wounding. Using specific inhibitors, we characterized one MnSOD and two CuZnSOD isozymes. CuZnSOD activities decreased notably 12 h after treatment. The activities of dehydroascorbate reductase and glutathione reductase increased dramatically following the wounding treatment, possibly as a means to compensate for the redox changes due to ROS production.

Non-native Soluble Oligomers of Cu/Zn Superoxide Dismutase (SOD1) Contain a Conformational Epitope Linked to Cytotoxicity in Amyotrophic Lateral Sclerosis (ALS)

PubMed Central

2015-01-01

Soluble misfolded Cu/Zn superoxide dismutase (SOD1) is implicated in motor neuron death in amyotrophic lateral sclerosis (ALS); however, the relative toxicities of the various non-native species formed by SOD1 as it misfolds and aggregates are unknown. Here, we demonstrate that early stages of SOD1 aggregation involve the formation of soluble oligomers that contain an epitope specific to disease-relevant misfolded SOD1; this epitope, recognized by the C4F6 antibody, has been proposed as a marker of toxic species. Formation of potentially toxic oligomers is likely to be exacerbated by an oxidizing cellular environment, as evidenced by increased oligomerization propensity and C4F6 reactivity when oxidative modification by glutathione is present at Cys-111. These findings suggest that soluble non-native SOD1 oligomers, rather than native-like dimers or monomers, share structural similarity to pathogenic misfolded species found in ALS patients and therefore represent potential cytotoxic agents and therapeutic targets in ALS. PMID:24660965

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

PubMed

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

1999-09-15

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

CuInS2/ZnS QD exposure induces developmental toxicity, oxidative stress and DNA damage in rare minnow (Gobiocypris rarus) embryos and larvae.

PubMed

Liu, Li; Xiao, Yuan-Yuan; Ji, Yan-Hong; Liu, Ming-Zhi; Chen, Yao; Zeng, Yu-Lian; Zhang, Yao-Guang; Jin, Li

2017-08-01

Chinese rare minnow (Gobiocypris rarus) embryos were used as an experimental model to investigate the effects of CuInS 2 /ZnS quantum dots (QDs) on the early life stages of G. rarus. Normal developmental parameters (survival rate, body length and average heart rate), biomarker genes [stress response (Hsp70), detoxification (Cyp1a), organizer function and axis formation (Wnt8α), and muscle (Mstn)], enzymatic activity and DNA damage were recorded as endpoints in the developing embryos/larvae after exposure until 96h post-fertilization (hpf). Reduced survival rate, decreased heart rate, altered body length, increased malformation rate, decreased hatching rate, advanced hatching time in response to low concentrations (50 and 100nmol/L) and delayed hatching time in response to high concentrations were observed after exposure, as were many other toxic effects, including pericardial edema and bent tails. The 72 hpf LC 50 (median lethal concentration) was determined to be 624.364nmol/L. Treatment with certain concentrations of CuInS 2 /ZnS QDs significantly increased the superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels and significantly induced DNA damage. After treatment with CuInS 2 /ZnS QDs, the embryos showed highly up-regulated expression of Hsp70, Cyp1a and Wnt8a and significantly up-regulated expression of Mstn at 12 hpf. Overall, this study indicates that CuInS 2 /ZnS QDs are potentially toxic to G. rarus embryos. The information presented in this study will be helpful for fully understanding the toxicity induced by CuInS 2 /ZnS QDs in fish embryos. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of fosinopril and losartan on renal Klotho expression and oxidative stress in spontaneously hypertensive rats.

PubMed

Tang, Rong; Zhou, Qiaoling; Liu, Zhichun; Xiao, Zhou; Pouranan, Veeraragoo

2011-01-01

To explore effects of fosinopril and losartan on renal Klotho expression and oxidative stress in spontaneously hypertensive rats (SHR) and the mechanisms underlying the protection against renal damage. Fifteen male SHRs (22 weeks old) were randomly divided into 3 groups (n=5 in each group): a SHR group, a fosinopril group [10 mg/(kg.d)], and a losartan group [50 mg/(kg.d)]. Age-matched Wistar-Kyoto (WKY) rats were chosen for a control group. Eight weeks later, tail arterial pressure, 24 hours urinary protein (Upro),urinary N-acetyl-β-D-glucosaminidase (NAGase) were measured. Renal pathological changes were examined under light microscopy by HE staining. The renal mRNA and protein expression of Klotho were determined by RT-PCR, immunohistochemical staining or Western blot. The levels of total antioxidant capacity (TAOC), malondialdehyde (MDA), Cu/Zn superoxide dismutase (Cu/Zn-SOD), Mn superoxide dismutase (Mn-SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) were determined. The typical pathological characteristics of hypertensive renal damage were observed in the kidney of the SHR group.Compared with the SHR group, the systolic pressure, Upro, and urinary NAGase, the content of MDA and renal pathological damage was reduced while the renal Klotho expression and activities of TAOC, Cu/Zn-SOD, CAT, and GSH-Px were increased (P<0.05 or P<0.01) in the fosinopril or losartan group. There was no significant difference in renal Mn-SOD level among the 4 groups (P>0.05). Fosinopril and losartan can exert protection against hypertensive renal damage through upregulating Klotho expression as well as reducing oxidative stress.

Antioxidant defenses of Onychostoma macrolepis in response to thermal stress: Insight from mRNA expression and activity of superoxide dismutase and catalase.

PubMed

Yu, Haibo; Deng, Wei; Zhang, Dongdong; Gao, Yao; Yang, Zhou; Shi, Xiaochen; Sun, Jian; Zhou, Jishu; Ji, Hong

2017-07-01

Onychostoma macrolepis has becoming an endangered fish species in China, which population gradually declined in the past few decades due to the changing environment including elevated water temperature resulted from adverse weather events. The present study determined antioxidant defenses of O. macrolepis in response to thermal stress, aiming to understand the role of antioxidant system in adaptation of thermal stress for O. macrolepis. Experimental fish which were acclimated at 24 °C were stressed at 30 °C for 0 h, 1 h, 3 h, 6 h, 12 h, 24 h and 48 h, respectively. Change in mRNA expression of Cu/Zn superoxide dismutase (Cu/Zn-SOD) and catalase (CAT) and activity of SOD and CAT of the experimental fish with different stress time were determined. We cloned the full-length cDNA of Cu/Zn-SOD and CAT by means of RACE method, and analyzed their molecular characterization and tissue distribution. We discovered that the mRNA expression of the Cu/Zn-SOD in heart, liver, spleen, gill, intestine and the CAT in heart, liver, spleen, kidney, intestine and muscle of O. macrolepis significantly increased when water temperature increased from 24 °C to 30 °C, indicating a sensitive response of mRNA expression of Cu/Zn-SOD and CAT to the thermal stress. Moreover, the mRNA expression of the Cu/Zn-SOD and CAT were varied in different tissues, indicating different sensitivity of the tissues in response to thermal stress. Activity of the SOD in serum of O. macrolepis gradually increased from 1 h to 12 h sampling time, but significantly decreased at 24 h sampling time, compared to that of 0 h sampling time. And activity of the CAT in serum of O. macrolepis significantly decreased from 1 h to 12 h sampling time, and did not changed significantly at 24 h and 48 h sampling time, compared to that of 0 h sampling time. As such, MDA contents in the serum of O. macrolepis significantly decreased from 1 h to 6 h sampling time, but significantly increased at 12 h and 24 h sampling time, compared to that of 0 h sampling time. In summary, antioxidant system of the O. macrolepis can quickly response to short term thermal stress at 30 °C in form of both the mRNA expression of Cu/Zn-SOD and CAT and the activity of SOD and CAT, and consequently enhance the antioxidant defenses of O. macrolepis. However, thermal stress at 30 °C for 12 h-24 h seems to lead to oxidative damage of the O. macrolepis. Copyright © 2017 Elsevier Ltd. All rights reserved.

The association of oxidant-antioxidant status in patients with chronic renal failure.

PubMed

Aziz, Manal A; Majeed, Ghanim H; Diab, Kareem S; Al-Tamimi, Raid J

2016-01-01

Oxidative stress has been linked to disease progression, including chronic renal failure (CRF). The aim of the present study was to determine malondialdehyde (MDA) as a sign of lipid peroxidation, and to investigate the association between antioxidant activities and three trace elements, in 49 patients with CRF. The erythrocyte and plasma trace elements [selenium (Se), zinc (Zn), and copper (Cu)] and antioxidant defense levels were determined: glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), vitamins E and C. The obtained values were compared with 42 age- and sex-matched healthy controls. There were significantly lower mean values of plasma Se, GPx, vitamins E and C, erythrocyte Se, SOD and CAT levels in the patient group compared to the control group (p < 0.001). Plasma MDA showed a significant increase in all CRF patients in comparison with controls. No significant difference was found in plasma Cu, Zn, and erythrocyte GPx, Cu and Zn levels between patient and control groups. These findings indicate oxidative stress is present in patients of CRF, and may serve to establish a simple protocol for evaluation of renal function.

Zymography Methods to Simultaneously Analyze Superoxide Dismutase and Catalase Activities: Novel Application for Yeast Species Identification.

PubMed

Gamero-Sandemetrio, Esther; Gómez-Pastor, Rocío; Matallana, Emilia

2017-01-01

We provide an optimized protocol for a double staining technique to analyze superoxide dismutase enzymatic isoforms Cu-Zn SOD (Sod1) and Mn-SOD (Sod2) and catalase in the same polyacrylamide gel. The use of NaCN, which specifically inhibits yeast Sod1 isoform, allows the analysis of Sod2 isoform while the use of H 2 O 2 allows the analysis of catalase. The identification of a different zymography profiling of SOD and catalase isoforms in different yeast species allowed us to propose this technique as a novel yeast identification and classification strategy.

Copper exposure induces oxidative injury, disturbs the antioxidant system and changes the Nrf2/ARE (CuZnSOD) signaling in the fish brain: protective effects of myo-inositol.

PubMed

Jiang, Wei-Dan; Liu, Yang; Hu, Kai; Jiang, Jun; Li, Shu-Hong; Feng, Lin; Zhou, Xiao-Qiu

2014-10-01

The brain is the center of the nervous system in all vertebrates, and homeostasis of the brain is crucial for fish survival. Copper (Cu) is essential for normal cellular processes in most eukaryotic organisms but is toxic in excess. Although Cu is indicated as a potent neurotoxicant, information regarding its threat to fish brain and underlying mechanisms is still scarce. In accordance, the objective of this study was to assess the effects and the potential mechanism of Cu toxicity by evaluating brain oxidative status, the enzymatic and mRNA levels of antioxidant genes, as well as the Nrf2/ARE signaling in the brain of fish after Cu exposure. The protective effects of myo-inositol (MI) against subsequent Cu exposure were also investigated. The results indicate that induction of oxidative stress by Cu is shown by increases in brain ROS production, lipid peroxidation and protein oxidation, which are accompanied by depletions of antioxidants, including total superoxide dismutase (T-SOD), CuZnSOD, glutathione-S-transferase (GST) and glutathione reductase (GR) activities and glutathione (GSH) content. Cu exposure increased the catalase (CAT) and glutathione peroxidase (GPx) activities. Further molecular results showed that Cu exposure up-regulated CuZnSOD, GPx1a and GR mRNA levels, suggesting an adaptive mechanism against stress. Moreover, Cu exposure increased fish brain Nrf2 nuclear accumulation and increased its ability of binding to ARE (CuZnSOD), which supported the increased CuZnSOD mRNA levels. In addition, Cu exposure caused increases of the expression of the Nrf2, Maf G1 (rather than Maf G2 gene) and PKCd genes, suggesting that de novo synthesis of those factors is required for the protracted induction of such antioxidant genes. However, the modulation of Keap1a (rather than Keap1b) of fish brain under Cu exposure might be used to turn off of the signaling cascade and avoid harmful effects. Interestingly, pre-treatment of fish with MI prevented the fish brain from Cu-induced oxidative damages mainly by increasing the GSH content and CuZnSOD and GST activities. Summarily, this study indicates that although Cu stimulates adaptive increases in the expression of some antioxidant enzyme genes through Nrf2/ARE signaling, it also induces oxidation and the depletion of most of antioxidant enzyme activities and GSH content due to the increase of ROS production, and MI protects the fish brain against Cu toxicity. Copyright © 2014 Elsevier B.V. All rights reserved.

Modification of a single tryptophan residue in human Cu,Zn-superoxide dismutase by peroxynitrite in the presence of bicarbonate.

PubMed

Yamakura, F; Matsumoto, T; Fujimura, T; Taka, H; Murayama, K; Imai, T; Uchida, K

2001-07-09

Human recombinant Cu,Zn-SOD was reacted with peroxynitrite in a reaction mixture containing 150 mM potassium phosphate buffer (pH 7.4) 25 mM sodium bicarbonate, and 0.1 mM diethylenetriamine pentaacetic acid. Disappearance of fluorescence emission at 350 nm, which could be attributed to modification of a single tryptophan residue, was observed in the modified enzyme with a pH optimum of around 8.4. A fluorescence decrease with the same pH optimum was also observed without sodium bicarbonate, but with less efficiency. Amino acid contents of the modified enzyme showed no significant difference in all amino acids except the loss of a single tryptophan residue of the enzyme. The peroxynitrite-modified enzyme showed an increase in optical absorption around 350 nm and 30% reduced enzyme activity based on the copper contents. The modified enzyme showed the same electron paramagnetic resonance spectrum as that of the control enzyme. The modified Cu,Zn-SOD showed a single protein band in sodium dodecyl sulfate--polyacrylamide gel electrophoresis (SDS--PAGE) and five protein bands in non-denaturing PAGE. From this evidence, we conclude that nitration and/or oxidation of the single tryptophan 32 and partial inactivation of the enzyme activity of Cu,Zn-SOD is caused by a peroxynitrite-carbon dioxide adduct without perturbation of the active site copper integrity.

Intestinal cell targeting of a stable recombinant Cu-Zn SOD from Cucumis melo fused to a gliadin peptide.

PubMed

Intes, Laurent; Bahut, Muriel; Nicole, Pascal; Couvineau, Alain; Guette, Catherine; Calenda, Alphonse

2012-05-31

The mRNA encoding full length chloroplastic Cu-Zn SOD (superoxide dismutase) of Cucumis melo (Cantaloupe melon) was cloned. This sequence was then used to generate a mature recombinant SOD by deleting the first 64 codons expected to encode a chloroplastic peptide signal. A second hybrid SOD was created by inserting ten codons to encode a gliadin peptide at the N-terminal end of the mature SOD. Taking account of codon bias, both recombinant proteins were successfully expressed and produced in Escherichia coli. Both recombinant SODs display an enzymatic activity of ~5000U mg(-1) and were shown to be stable for at least 4h at 37°C in biological fluids mimicking the conditions of intestinal transit. These recombinant proteins were capable in vitro, albeit at different levels, of reducing ROS-induced-apoptosis of human epithelial cells. They also stimulated production and release in a time-dependent manner of an autologous SOD activity from cells located into jejunum biopsies. Nevertheless, the fused gliadin peptide enable the recombinant Cu-Zn SOD to maintain a sufficiently sustained interaction with the intestinal cells membrane in vivo rather than being eliminated with the flow. According to these observations, the new hybrid Cu-Zn SOD should show promise in applications for managing inflammatory bowel diseases. Copyright © 2012 Elsevier B.V. All rights reserved.

Isotopic Evidence of Unaccounted for Fe and Cu Erythropoietic Pathways

NASA Astrophysics Data System (ADS)

Albarede, F.; Telouk, P.; Lamboux, A.; Jaouen, K.; Balter, V.

2011-12-01

Despite its potential importance for understanding perturbations in the Fe-Cu homeostatic pathways, the natural isotopic variability of these metals in the human body remains unexplored. We measured the Fe, Cu, and Zn isotope compositions of total blood, serum, and red blood cells of ~50 young blood donors by multiple-collector ICP-MS after separation and purification by anion exchange chromatography. Zn is on average 0.2 permil heavier in erythrocytes (δ 66Zn=0.44±0.33 permil) with respect to serum but shows much less overall isotopic variability than Fe and Cu, which indicates that isotope fractionation depends more on redox conditions than on ligand coordination. On average, Fe in erythrocytes (δ 56Fe=-2.59±0.47 permil) is isotopically light by 1-2 permil with respect to serum, whereas Cu in erythrocytes (δ 65Cu=0.56±0.50 permil) is 0.8 percent heavier. Fe and Cu isotope compositions clearly separate erythrocytes of men and women. Fe and Cu from B-type men erythrocytes are visibly more fractionated than all the other blood types. Isotope compositions provide an original method for evaluating metal mass balance and homeostasis. Natural isotope variability shows that the current models of Fe and Cu erythropoiesis, which assume that erythropoiesis is restricted to bone marrow, violate mass balance requirements. It unveils unsuspected major pathways for Fe, with erythropoietic production of isotopically heavy ferritin and hemosiderin, and for Cu, with isotopically light Cu being largely channeled into blood and lymphatic circulation rather than into superoxide dismutase-laden erythrocytes. Iron isotopes provide an intrinsic measuring rod of the erythropoietic yield, while Cu isotopes seem to gauge the relative activity of erythropoiesis and lymphatics.

Anemia induced by high zinc intake in chicks: Mechanisms

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

Pimentel, J.L.; Greger, J.L.; Cook, M.E.

1991-03-15

The mechanisms by which excess Zn induced anemia in chickens was assessed in 8 studies in which chicks were randomly assigned to a 2 {times} 2 factorial arrangement of treatments with 60 or 2,000 {mu}g Zn and 10 or 250 {mu}g Cu/g diet. Less Fe-59 appeared in the plasma 1 hour after a labeled meal when chicks were fed excess Zn in 1 of 2 studies but less Fe-59 appeared in livers of chicks fed excess Zn in both studies. The decrease of Fe-59 uptake into tissues paralleled a decrease in Fe concentrations in livers and tibiotarsi. These differences inmore » tissue Fe did not reflect differences in Fe excretion because excretion and incorporation into tissues of injected Fe-59 was not affected by high Zn intake. Although excess Zn decreased tissue Cu concentrations, excess Zn, per se, did not affect cytosolic superoxide dismutase activity, the in vivo t 1/2 of erythrocytes, or erythrocyte hemolysis in vitro. The decrease in body weight of chicks fed excess Zn indicated that protein synthesis and/or degradation could be affected. Increased incorporation of C-14 tyrosine into liver and bone marrow of chicks fed excess Zn suggested increased protoporphyrin synthesis or metallothionein synthesis. These results indicated that decreased Fe absorption was the primary mechanism by which excess Zn induced anemia.« less

Autoradiographic evidence for methamphetamine-induced striatal dopaminergic loss in mouse brain: attenuation in CuZn-superoxide dismutase transgenic mice.

PubMed

Hirata, H; Ladenheim, B; Carlson, E; Epstein, C; Cadet, J L

1996-04-01

Methamphetamine (METH) has long-lasting neurotoxic effects on the nigrostriatal dopamine (DA) system of rodents. METH-induced neurotoxicity is thought to involve release of DA in presynaptic DA terminals, which is associated with increased formation of oxygen-based free radicals. We have recently shown that METH-induced striatal DA depletion is attenuated in transgenic (Tg) mice that express the human CuZn-superoxide dismutase (SOD) enzyme. That study did not specifically address the issue of loss of DA terminals. In the present study, we have used receptor autoradiographic studies of [(125)I]RTI-121-labeled DA uptake sites to evaluate the effects of several doses of METH on striatal DA terminals of Non-Tg as well as of heterozygous and homozygous SOD-Tg mice. In Non-Tg mice, METH caused decreases in striatal DA uptake sites in a dose-dependent fashion. The loss of DA terminals was more prominent in the lateral region than in the medial subdivisions of the striatum. In SOD-Tg mice, the loss of DA terminals caused by METH was attenuated in a gene dosage-dependent fashion, with the homozygous mice showing the greatest protection. Female mice were somewhat more resistant than male mice against these deleterious effects of METH. These results provide further evidence for a role of superoxide radicals in the long-term effects of METH. They also suggest the notion of a gender-specific handling of oxidative stress.

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

PubMed Central

2014-01-01

Background Cassava (Manihot esculenta Crantz) is a tropical root crop, and is therefore, extremely sensitive to low temperature; its antioxidative response is pivotal for its survival under stress. Timely turnover of reactive oxygen species (ROS) in plant cells generated by chilling-induced oxidative damages, and scavenging can be achieved by non-enzymatic and enzymatic reactions in order to maintain ROS homeostasis. Results Transgenic cassava plants that co-express cytosolic superoxide dismutase (SOD), MeCu/ZnSOD, and ascorbate peroxidase (APX), MeAPX2, were produced and tested for tolerance against oxidative and chilling stresses. The up-regulation of MeCu/ZnSOD and MeAPX2 expression was confirmed by the quantitative reverse transcriptase-polymerase chain reaction, and enzymatic activity analyses in the leaves of transgenic cassava plant lines with a single-transgene integration site. Upon exposure to ROS-generating agents, 100 μM ROS-generating reagent methyl viologen and 0.5 M H2O2, higher levels of enzymatic activities of SOD and APX were detected in transgenic plants than the wild type. Consequently, the oxidative stress parameters, such as lipid peroxidation, chlorophyll degradation and H2O2 synthesis, were lower in the transgenic lines than the wild type. Tolerance to chilling stress at 4°C for 2 d was greater in transgenic cassava, as observed by the higher levels of SOD, catalase, and ascorbate-glutathione cycle enzymes (e.g., APX, monodehydroascorbate reductase, dehydroascorbate reducatase and glutathione reductase) and lower levels of malondialdehyde content. Conclusions These results suggest that the expression of native cytosolic SOD and APX simultaneously activated the antioxidative defense mechanisms via cyclic ROS scavenging, thereby improving its tolerance to cold stress. PMID:25091029

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

PubMed

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

2014-08-05

Cassava (Manihot esculenta Crantz) is a tropical root crop, and is therefore, extremely sensitive to low temperature; its antioxidative response is pivotal for its survival under stress. Timely turnover of reactive oxygen species (ROS) in plant cells generated by chilling-induced oxidative damages, and scavenging can be achieved by non-enzymatic and enzymatic reactions in order to maintain ROS homeostasis. Transgenic cassava plants that co-express cytosolic superoxide dismutase (SOD), MeCu/ZnSOD, and ascorbate peroxidase (APX), MeAPX2, were produced and tested for tolerance against oxidative and chilling stresses. The up-regulation of MeCu/ZnSOD and MeAPX2 expression was confirmed by the quantitative reverse transcriptase-polymerase chain reaction, and enzymatic activity analyses in the leaves of transgenic cassava plant lines with a single-transgene integration site. Upon exposure to ROS-generating agents, 100 μM ROS-generating reagent methyl viologen and 0.5 M H₂O₂, higher levels of enzymatic activities of SOD and APX were detected in transgenic plants than the wild type. Consequently, the oxidative stress parameters, such as lipid peroxidation, chlorophyll degradation and H₂O₂ synthesis, were lower in the transgenic lines than the wild type. Tolerance to chilling stress at 4°C for 2 d was greater in transgenic cassava, as observed by the higher levels of SOD, catalase, and ascorbate-glutathione cycle enzymes (e.g., APX, monodehydroascorbate reductase, dehydroascorbate reducatase and glutathione reductase) and lower levels of malondialdehyde content. These results suggest that the expression of native cytosolic SOD and APX simultaneously activated the antioxidative defense mechanisms via cyclic ROS scavenging, thereby improving its tolerance to cold stress.

Structural analysis and molecular modelling of the Cu/Zn-SOD from fungal strain Humicola lutea 103

NASA Astrophysics Data System (ADS)

Dolashka, Pavlina; Moshtanska, Vesela; Dolashki, Aleksander; Velkova, Lyudmila; Rao, Gita Subba; Angelova, Maria; Betzel, Christian; Voelter, Wolfgang; Atanasov, Boris

2011-12-01

The native form of Cu/Zn-superoxide dismutase, isolated from fungal strain Humicola lutea 103 is a homodimer that coordinates one Cu(2+) and one Zn(2+) per monomer. Cu(2+) and Zn(2+) ions play crucial roles in enzyme activity and structural stability, respectively. It was established that HLSOD shows high pH and temperature stability. Thermostability of the glycosylated enzyme Cu/Zn-SOD, isolated from fungal strain H. lutea 103, was determined by CD spectroscopy. Determination of reversibility toward thermal denaturation for HLSOD allowed several thermodynamic parameters to be calculated. In this communication we report the conditions under which reversible denaturation of HLSOD exists. The narrow range over which the system is reversible has been determined using the strongest test of two important thermodynamic independent variables (T and pH). Combining both these variables, the "phase diagram" was determined, as a result of which the real thermodynamic parameters (Δ Cp, ΔHexp°, and ΔGexp°) was established. Because very narrow pH-interval of transitions we assume they are as result of overlapping of two simple transitions. It was found that Δ Ho is independent from pH with a value of 1.3 kcal/mol and 2.8 kcal/mol for the first and the second transition, respectively. Δ Go was pH-dependent in all studied pH-interval. This means that the transitions are entropically driven, these. Based on this, these processes can be described as hydrophobic rearrangement of the quaternary structure. It was also found that glycosylation does not influence the stability of the enzyme because the carbohydrate chain is exposed on the surface of the molecule.

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

PubMed Central

La, Mylinh; Rand, Michael J

1999-01-01

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

Stability of Benzotriazole Derivatives with Free Cu, Zn, Co and Metal-Containing Enzymes: Binding and Interaction of Methylbenzotriazoles with Superoxide Dismutase and Vitamin B12

NASA Astrophysics Data System (ADS)

Abudalo, R. A.; AbuDalo, M. A.; Hernandez, M. T.

2018-02-01

Benzotriazole derivatives form very strong bonds with transition metals, and are the most widely used type of industrial corrosion inhibitor. Some benzotriazole derivatives have been implicated as hormone regulators which also carry the ability to induce uncoupling responses or otherwise inhibit respiration processes in some microorganisms. However, the mechanisms associated with benzotriazole toxicity and inhibition are unknown. Using Differential Pulse Polarography, the stability constants of commercially significant corrosion inhibitors, 4-and 5-methylbenzotriazole, coordinated with free Cu (II) and Co (III), were determined to be 1015 and 108, respectively. Polarographic analyses were extended to confirm that methylbenzotriazole also binds the copper center(s) in the ubiquitous enzyme superoxide dismutase, and the Corrin site in the coenzyme cobalamin (vitamin B12). These results suggest that the metal-chelating ability of this unique class of compounds may confer inhibition to certain enzyme systems.

Increase of rutin antioxidant activity by generating Maillard reaction products with lysine.

PubMed

Zhang, Ru; Zhang, Bian-Ling; He, Ting; Yi, Ting; Yang, Ji-Ping; He, Bin

2016-06-01

Rutin exists in medicinal herbs, fruits, vegetables, and a number of plant-derived sources. Dietary sources containing rutin are considered beneficial because of their potential protective roles in multiple diseases related to oxidative stresses. In the present study, the change and antioxidation activity of rutin in Maillard reaction with lysine through a heating process were investigated. There is release of glucose and rhamnose that interact with lysine to give Maillard reaction products (MRPs), while rutin is converted to less-polar quercetin and a small quantity of isoquercitrin. Because of their high cell-membrane permeability, the rutin-lysine MRPs increase the free radical-scavenging activity in HepG2 cells, showing cellular antioxidant activity against Cu(2+)-induced oxidative stress higher than that of rutin. Furthermore, the MRPs significantly increased the Cu/Zn SOD (superoxide dismutase) activity and Cu/Zn SOD gene expression of HepG2 cells, consequently enhancing antioxidation activity. Copyright © 2016 Elsevier Ltd. All rights reserved.

A multielement trace mineral injection improves liver copper and selenium concentrations and manganese superoxide dismutase activity in beef steers.

PubMed

Genther, O N; Hansen, S L

2014-02-01

Trace minerals (TM) are vital to health and growth of livestock, but low dietary concentrations and dietary antagonists may reduce mineral status and feeder cattle TM status is usually unknown at arrival. The objective of this study was to examine the effect of TM status on response to mineral injection in beef cattle. Forty steers were equally assigned to diets for an 84-d depletion period: control (CON; supplemental Cu, Mn, Se, and Zn) or deficient (DEF; no supplemental Cu, Mn, Se, or Zn plus Fe and Mo as TM antagonists). Lesser liver Cu and Se concentrations (79.0 ± 11.60 and 1.66 ± 0.080 mg/kg DM, respectively) in DEF steers compared with CON steers (228.8 ± 11.60 and 2.41 ± 0.080 mg/kg DM, respectively) on d 71 of depletion indicated mild deficiencies of these TM (P < 0.001). On d 1 of the 85-d repletion period, 10 steers within each dietary treatment were injected with sterilized saline (SAL) or Multimin90 (MM), containing 15, 10, 5, and 60 mg/mL of Cu, Mn, Se, and Zn, respectively, at a dose of 1 mL/68 kg BW. All steers were fed the same repletion diet supplemented with Cu, Mn, Se, and Zn to meet or exceed NRC recommendations. Blood was collected on d 0 and 1, and blood and liver biopsies were collected on d 8, 15, 29, 57, and 85 postinjection. Red blood cell lysate manganese-superoxide dismutase activity was greater in MM (P = 0.02), suggesting incorporation of injectable TM into a biological process. The increase in liver Se in response to MM was greater in CON vs. DEF (P = 0.02), suggesting TM from injection were used rather than stored in DEF steers. Liver Se and Cu (P < 0.05) were elevated through at least d 30 by MM. Dietary TM deficiency decreased neutrophil bacteria killing ability and increased myeloperoxidase (MPO) degranulation (P < 0.04) as measured on d 0, 1, 13, and 14 during the repletion period while injection had no impact. Within CON animals, total MPO was greater in animals that received TM injection, but injection did not affect MPO within DEF steers (P = 0.007). Overall, TM from an injectable mineral were used differently between TM adequate and mildly deficient steers.

Enzymatic antioxidant system of endotheliocytes.

PubMed

Sharapov, M G; Goncharov, R G; Gordeeva, A E; Novoselov, V I; Antonova, O A; Tikhaze, A K; Lankin, V Z

2016-11-01

It is shown that endothelial cells from human umbilical vein have a reduced activity and gene expression of the "classic" antioxidant enzymes (Cu,Zn-superoxide dismutase, catalase, and Se-containing glutathione peroxidase). At the same time, a high expression level of peroxiredoxin genes was identified in the same endothelial cells, which obviously indicates the predominant involvement of these enzymes in protecting the endothelium from the damaging effect of free radical peroxidation.

Identifying Haemophilus haemolyticus and Haemophilus influenzae by SYBR Green real-time PCR.

PubMed

Latham, Roger; Zhang, Bowen; Tristram, Stephen

2015-05-01

SYBR Green real time PCR assays for protein D (hpd), fuculose kinase (fucK) and [Cu, Zn]-superoxide dismutase (sodC) were designed for use in an algorithm for the identification of Haemophilus influenzae and H. haemolyticus. When tested on 127 H. influenzae and 60 H. haemolyticus all isolates were identified correctly. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.

Identification Of Protein Vaccine Candidates Using Comprehensive Proteomic Analysis Strategies

DTIC Science & Technology

2007-12-01

urease (URE) gene codes for a urea amidohydrolase protein that catalyzes urea hydrolysis. The protein was first isolated from C. immitis and...the Cu, Zn, Superoxide Dismutase (SOD), the Spherule Outer Wall glycoprotein (SOWgp), the T-Cell Reactive Protein (TCRP), and Urease (URE). It is...et al. 1997. Isolation and characterization of the urease gene (URE) from the pathogenic fungus Coccidioides immitis. Gene 198: 387-391. 54. Li, K

Treadmill exercise prevents diabetes-induced increases in lipid peroxidation and decreases in Cu,Zn-superoxide dismutase levels in the hippocampus of Zucker diabetic fatty rats.

PubMed

Kim, Jong Whi; Chae, Junghyun; Nam, Sung Min; Kim, Yo Na; Yoo, Dae Young; Choi, Jung Hoon; Jung, Hyo Young; Song, Wook; Hwang, In Koo; Seong, Je Kyung; Yoon, Yeo Sung

2015-01-01

In the present study, we investigated the effects of treadmill exercise on lipid peroxidation and Cu,Zn-superoxide dismutase (SOD1) levels in the hippocampus of Zucker diabetic fatty (ZDF) rats and lean control rats (ZLC) during the onset of diabetes. At 7 weeks of age, ZLC and ZDF rats were either placed on a stationary treadmill or made to run for 1 h/day for 5 consecutive days at 16~22 m/min for 5 weeks. At 12 weeks of age, the ZDF rats had significantly higher blood glucose levels and body weight than the ZLC rats. In addition, malondialdehyde (MDA) levels in the hippocampus of the ZDF rats were significantly higher than those of the ZLC rats whereas SOD1 levels in the hippocampus of the ZDF rats were moderately decreased. Notably, treadmill exercise prevented the increase of blood glucose levels in ZDF rats. In addition, treadmill exercise significantly ameliorated changes in MDA and SOD1 levels in the hippocampus although SOD activity was not altered. These findings suggest that diabetes increases lipid peroxidation and decreases SOD1 levels, and treadmill exercise can mitigate diabetes-induced oxidative damage in the hippocampus.

Subacute Oxidative Stress and Glial Reactivity in the Amygdala are Associated with Increased Anxiety Following Blast Neurotrauma.

PubMed

Sajja, Venkata Siva Sai Sujith; Hubbard, William B; VandeVord, Pamela J

2015-08-01

Behavioral symptoms, such as anxiety, are widely reported after blast overpressure (BOP) exposure. Amygdalar vulnerability to increasing magnitudes of BOP has not been investigated, and single exposures to blast have been limited to acute (<72 h) assessment. Rats were exposed to a single low, moderate, or high BOP (10, 14, or 24 psi) with an advanced blast simulator to test the susceptibility of the amygdala. Anxiety-like behavior was observed in the low- and moderate-pressure groups when subjected to the light/dark box assessment 7 days after the blast but not in high-pressure group. Immunohistochemistry was performed to measure apoptosis (cleaved caspase-3), neuronal loss (NeuN), reactive astrocytes (glial fibrillary acidic protein), microglia (Iba-1), and oxidative stress (CuZn superoxide dismutase). Slower progression of injury cascades was associated with a significant increase in anxiety, apoptosis, and astrogliosis in the low pressure group compared with others. A significant increase of CuZn superoxide dismutase in the low pressure group could be associated with neuroprotection from cell death caused by oxidative stress because neuronal loss was significant in the moderate- and high- but not the low-pressure group. Overall, this study demonstrated that overpressure as low as 10 psi can induce subacute anxiety, in addition to neuropathologic changes in the amygdala.

QM/MM Calculation of the Enzyme Catalytic Cycle Mechanism for Copper- and Zinc-Containing Superoxide Dismutase.

PubMed

Lintuluoto, Masami; Yamada, Chiaki; Lintuluoto, Juha M

2017-08-03

The entire enzyme catalytic mechanism including the electron and the proton transfers of the copper- and zinc-containing extracellular superoxide dismutase (SOD3) was investigated by using QM/MM method. In the first step, the electron transfer from O 2 ·- to SOD3 occurred without the bond formation between the donor and the acceptor and formed the triplet oxygen molecule and reduced SOD3. In the reduced SOD3, the distorted tetrahedral structure of Cu(I) atom was maintained. The reduction of Cu(II) atom induced the protonation of His113, which bridges between the Cu(II) and Zn(II) atoms in the resting state. Since the protonation of His113 broke the bond between Cu(I) and His113, three-coordinated Cu(I) was formed. Further, we suggest the binding of O 2 ·- formed hydrogen peroxide and the resting state after both the Cu reduction and the protonation of His113. The protonation of His113 caused the conformational change of Arg186 located at the entrance of the reactive site. The electrostatic potential surface around the reactive site showed that Arg186 plays an important role as electrostatic guidance for the negatively charged substrates only after the protonation of His113. The rotation of Arg186 switched the proton supply routes via Glu108 or Glu179 for transferring two protons from the bulk solvent.

Evaluating the influence of National Research Council levels of copper, iron, manganese, and zinc using organic (Bioplex) minerals on resulting tissue mineral concentrations, metallothionein, and liver antioxidant enzymes in grower-finisher swine diets.

PubMed

Gowanlock, D W; Mahan, D C; Jolliff, J S; Hill, G M

2015-03-01

Graded levels of a trace mineral premix containing an organic (Bioplex) source of Cu, Fe, Mn, and Zn was evaluated with additional treatments containing organic Zn or Fe. Grower-finisher pigs were fed from 25 to 115 kg BW. The number of pigs in the experiment, the breeding/genetics of the pigs, the management, and the average age of the pigs were previously reported. The experiment was conducted as a randomized complete block design in 7 replicates. Treatments were 1) basal diet without supplemental Cu, Fe, Mn, and Zn; 2) basal diet + 2.5 mg/kg Cu, 50 mg/kg Fe, 1.5 mg/kg Mn, and 40 mg/kg Zn (50% NRC); 3) basal diet + 5 mg/kg Cu, 100 mg/kg Fe, 3 mg/kg Mn, and 80 mg/kg Zn (100% NRC); 4) basal diet + 25 mg Zn/kg; 5) basal diet + 50 mg Zn/kg; and 6) basal diet + 50 mg Fe/kg. Selenium and I were added to all diets at 0.3 and 0.14 mg/kg, respectively. Diets were composed of corn-soybean meal, dicalcium phosphate, and limestone with phytase added to enhance mineral availability. Three pigs per pen were bled at 55, 80, and 115 kg BW and plasma was analyzed for microminerals. When the average replicate BW was 115 kg, 3 pigs per pen of an equal gender ratio were killed. The liver, kidney, and heart were removed and analyzed for microminerals. Liver, duodenum, and jejunal metallothionein and the antioxidant enzymes in the liver containing these microminerals were determined. The results demonstrated that plasma minerals were unaffected at the 3 BW intervals. Liver and duodenum metallothionein protein were greater ( < 0.05) as dietary micromineral levels increased but jejunum metallothionein did not change as microminerals increased. The activity of Cu/Zn superoxide dismutase (SOD) was not affected as the levels of the micromineral increased, whereas the activity of Mn SOD increased slightly ( < 0.05) to the 50% NRC treatment level. Liver Zn (relative and total) increased ( < 0.05) as dietary micromineral levels increased and also when Zn was added singly to the diet. Liver, kidney, and heart Cu and Mn concentrations were similar at the various micromineral levels. The activities of liver enzymes containing graded levels of Zn were not affected by dietary microminerals at 115 kg BW. These results indicate that the supplemental levels of Cu, Fe, and Mn were not necessary for grower-finisher pigs and that these innate microminerals in a corn-soybean meal diet were adequate, whereas a need for supplemental Zn was demonstrated.

Regulation of trace elements and redox status in striatum of adult rats by long-term aerobic exercise depends on iron uptakes.

PubMed

Wu, Hua-Bo; Xiao, De-Sheng

2017-03-06

We investigated the effects of aerobic exercise (AE) on trace element contents and redox status in the striatum of rats with different diet iron. Weaned female rats were randomly fed with iron-adequate diet (IAD), iron-deficient diet (IDD), and iron-overloaded diet (IOD). After feeding their respective diet for 1 month, the rats fed with same diet were divided into swimming and maintaining sedentary (S) group. After 3 months, the non-heme iron (NHI), Mn, Cu, and Zn in the striatum were measured. Meanwhile, malonaldehyde acid (MDA), total superoxide dismutase activity, hydroxyl radical scavenging activity, and total antioxidant capacity were also analyzed. As compared with respective S rats, Mn, Cu, and Zn contents were significantly decreased in IDDE, but no significantly changes could be seen in IADE or IODE. A negative correlation of NHI with Cu contents in IDDE and positive correlations of NHI with Cu, or Zn contents in IADE, or with Mn or Cu contents in IODE were observed. In addition, striatum MDA was significantly decreased and anti-oxidative variables were increased in IODE compared to IODS. Our results suggest that the modification of trace elements and redox status in the striatum of rats caused by AE depends on dietary iron contents and that AE may also regulate the metabolic relationship of iron storage with other trace elements. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of Zinc Glycinate on Productive and Reproductive Performance, Zinc Concentration and Antioxidant Status in Broiler Breeders.

PubMed

Zhang, Ling; Wang, Yong-Xia; Xiao, Xue; Wang, Jiang-Shui; Wang, Qian; Li, Kai-Xuan; Guo, Tian-Yu; Zhan, Xiu-An

2017-08-01

An experiment was conducted to investigate the effects of zinc glycinate (Zn-Gly) supplementation as an alternative for zinc sulphate (ZnSO 4 ) on productive and reproductive performance, zinc (Zn) concentration and antioxidant status in broiler breeders. Six hundred 39-week-old Lingnan Yellow broiler breeders were randomly assigned to 6 groups consisting of 4 replicates with 25 birds each. Breeders were fed a basal diet (control group, 24 mg Zn/kg diet), basal diet supplemented with 80 mg Zn/kg diet from ZnSO 4 or basal diet supplemented with 20, 40, 60 and 80 mg Zn/kg diet from Zn-Gly. The experiment lasted for 8 weeks after a 4-week pre-test with the basal diet, respectively. Results showed that Zn supplementation, regardless of sources, improved (P < 0.05) the feed conversion ratio (kilogram of feed/kilogram of egg) and decreased broken egg rate, and elevated (P < 0.05) the qualified chick rate. Compared with the ZnSO 4 group, the 80 mg Zn/kg Zn-Gly group significantly increased (P < 0.05) average egg weight, fertility, hatchability and qualified chick rate, whereas it decreased (P < 0.05) broken egg rate. The Zn concentrations in liver and muscle were significantly higher (P < 0.05) in 80 mg Zn/kg Zn-Gly group than that in ZnSO 4 group. Compared with ZnSO 4 group, 80 mg Zn/kg Zn-Gly group significantly elevated (P < 0.05) the mRNA abundances of metallothionein (MT) and copper-zinc superoxide (Cu-Zn SOD), as well as the Cu-Zn SOD activity and MT concentration in liver. Moreover, the 80 mg Zn/kg Zn-Gly group had higher (P < 0.05) serum T-SOD and Cu-Zn SOD activities than that in the ZnSO 4 group. This study indicated that supplementation of Zn in basal diet improved productive and reproductive performance, Zn concentration and antioxidant status in broiler breeders, and the 80 mg Zn/kg from Zn-Gly was the optimum choice for broiler breeders compared with other levels of Zn from Zn-Gly and 80 mg/kg Zn from ZnSO 4 .

Alteration in the expression of antioxidant and detoxification genes in Chironomus riparius exposed to zinc oxide nanoparticles.

PubMed

Gopalakrishnan Nair, Prakash M; Chung, Ill Min

2015-12-01

Zinc oxide nanoparticles (ZnONPs) are widely used in several commercial products due to their unique physicochemical properties. However, their release into the aquatic environments through various anthropogenic activities will lead to toxic effect in aquatic organisms. Although several investigations have been reported on the effect of ZnONPs in aquatic organisms using traditional end points such as survival, growth, and reproduction, the molecular level end points are faster and sensitive. In this study, the expression of different genes involved in oxidative stress response, detoxification, and cellular defense was studied in an ecotoxicologically important bio-monitoring organism Chironomus riparius in order to understand the subcellular effects of ZnONPs. The fourth instar larvae were exposed to 0, 0.2, 2, 10, and 20 mg/L of ZnONPs and Zn ions (in the form of ZnSO4.7H2O) for 24 and 48 h period. The expression of CuZn superoxide dismutase, manganese superoxide dismutase, catalase, phospholipid hydroperoxide glutathione peroxidase, thioredoxin reductase 1 and delta-3, sigma-4 and epsilon-1 classes of glutathione S-transferases, cytochrome p4509AT2, and heat shock protein 70 were studied using real-time polymerase chain reaction method. Gene expression results showed that the expression of genes related to oxidative stress response was more pronounced as a result of ZnONPs exposure as compared to Zn ions. The mRNA expression of genes involved in detoxification and cellular protection was also modulated. Significantly higher expression levels of oxidative stress-related genes shows that oxidative stress is an important mechanism of toxicity as a result of ZnONPs exposure in C. riparius. Copyright © 2015 Elsevier Inc. All rights reserved.

Nitric oxide is a mediator of methamphetamine (METH)-induced neurotoxicity. In vitro evidence from primary cultures of mesencephalic cells.

PubMed

Sheng, P; Cerruti, C; Ali, S; Cadet, J L

1996-10-31

METH is a monoaminergic toxic that destroys dopamine terminals in vivo. Oxidative mechanisms associated with DA metabolism are thought to play an important role in its toxic effects. These ideas were supported by the demonstration that CuZn-superoxide dismutase (CuZnSOD) transgenic mice were protected against the toxic effects of the drug. In the present study, we sought to determine if nitric oxide (NO) production was also involved in METH-induced neurotoxicity using primary cultures obtained from fetal rat mesencephalon. METH caused dose- and time-dependent cell death in vitro. Blockade of nitric oxide (NO) formation with several nitric oxide (NO) synthase blockers attenuated METH-mediated toxicity. Moreover, inhibition of ADP-ribosylation with nicotinamide and benzamide also provided protection against the toxicity of the drug. These results, together with our previous results in transgenic mice, support a role for free radicals in METH-induced toxic effects.

Effects of Copper on Hemocyte Apoptosis, ROS Production, and Gene Expression in White Shrimp Litopenaeus vannamei.

PubMed

Guo, Hui; Li, Kexu; Wang, Wei; Wang, Chenggui; Shen, Yuchun

2017-10-01

Copper, a common chemical contaminant in aquatic environment, is known to be toxic to aquatic life at high concentrations. In the present study, we evaluated the apoptotic cell ratio and ROS production in hemocytes of the white shrimp Litopenaeus vannamei exposed to 1 or 5 mg L -1 Cu for 0, 3, 6, 12, 24, and 48 h. The expression changes of antioxidant biomarker genes, i.e., copper-zinc superoxide dismutase (Cu-Zn SOD) and catalase (CAT), apoptosis-related genes, i.e., caspase-3 and inhibitor of apoptosis protein (IAP), and a specific biomarker gene of heavy metal pollution, i.e., metallothionein (MT), were also determined in hemocytes. Significant increases in ROS production were observed in both treatment groups at each time points. The apoptotic cell ratios were significantly increased at 6-48 h among shrimp exposed to 1 mg L -1 Cu and at each time points in 5 mg L -1 Cu group. These results indicated that Cu would induce oxidative stress and apoptosis in the hemocyte of L. vannamei. Quantitative real-time PCR analysis revealed that the relative expression levels of Cu-Zn SOD, CAT, caspase-3, IAP, and MT were upregulated in a dose-dependent and time-dependent manner, suggesting the involvement of these genes in stress response against Cu exposure.

Distinct oxidative cleavage and modification of bovine [Cu-Zn]-SOD by an ascorbic acid/Cu(II) system: Identification of novel copper binding site on SOD molecule

PubMed Central

Uehara, Hiroshi; Luo, Shen; Aryal, Baikuntha; Levine, Rodney L.; Rao, V. Ashutosh

2016-01-01

We investigated the combined effect of ascorbate and copper [Asc/Cu(II)] on the integrity of bovine [Cu-Zn]-superoxide dismutase (bSOD1) as a model system to study the metal catalyzed oxidation (MCO) and fragmentation of proteins. We found Asc/Cu(II) mediates specific cleavage of bSOD1 and generates 12.5 and 3.2 kDa fragments in addition to oxidation/carbonylation of the protein. The effect of other tested transition metals, a metal chelator, and hydrogen peroxide on the cleavage and oxidation indicated that binding of copper to a previously unknown site on SOD1 is responsible for the Asc/Cu(II) specific cleavage and oxidation. We utilized tandem mass spectrometry to identify the specific cleavage sites of Asc/Cu(II)-treated bSOD1. Analyses of tryptic- and AspN-peptides have demonstrated the cleavage to occur at Gly31 with peptide bond breakage with Thr30 and Ser32 through diamide and α-amidation pathways, respectively. The three-dimensional structure of bSOD1 reveals the imidazole ring of His19 localized within 5 Angstrom from the α-carbon of Gly31 providing a structural basis that copper ion, most likely coordinated by His19, catalyzes the specific cleavage reaction. PMID:26872685

Distinct oxidative cleavage and modification of bovine [Cu- Zn]-SOD by an ascorbic acid/Cu(II) system: Identification of novel copper binding site on SOD molecule.

PubMed

Uehara, Hiroshi; Luo, Shen; Aryal, Baikuntha; Levine, Rodney L; Rao, V Ashutosh

2016-05-01

We investigated the combined effect of ascorbate and copper [Asc/Cu(II)] on the integrity of bovine [Cu-Zn]-superoxide dismutase (bSOD1) as a model system to study the metal catalyzed oxidation (MCO) and fragmentation of proteins. We found Asc/Cu(II) mediates specific cleavage of bSOD1 and generates 12.5 and 3.2kDa fragments in addition to oxidation/carbonylation of the protein. The effect of other tested transition metals, a metal chelator, and hydrogen peroxide on the cleavage and oxidation indicated that binding of copper to a previously unknown site on SOD1 is responsible for the Asc/Cu(II) specific cleavage and oxidation. We utilized tandem mass spectrometry to identify the specific cleavage sites of Asc/Cu(II)-treated bSOD1. Analyses of tryptic- and AspN-peptides have demonstrated the cleavage to occur at Gly31 with peptide bond breakage with Thr30 and Ser32 through diamide and α-amidation pathways, respectively. The three-dimensional structure of bSOD1 reveals the imidazole ring of His19 localized within 5Å from the α-carbon of Gly31 providing a structural basis that copper ion, most likely coordinated by His19, catalyzes the specific cleavage reaction. Published by Elsevier Inc.

Treatment with Parkinsonia aculeata combats insulin resistance-induced oxidative stress through the increase in PPARγ/CuZn-SOD axis expression in diet-induced obesity mice.

PubMed

Araújo, Tiago Gomes; Oliveira, Alexandre Gabarra; Vecina, Juliana Falcato; Marin, Rodrigo Miguel; Franco, Eryvelton Souza; Abdalla Saad, Mario J; de Sousa Maia, Maria Bernadete

2016-08-01

Parkinsonia aculeata L. (Caesalpiniaceae) is a traditional ethnomedicine and has been used for the empiric treatment of hyperglycemia, without scientific background. Mechanistic analyses at molecular level from the antioxidant mechanism observed by P. aculeata are required. Herein the effects of the treatment by hydroethanolic extract partitioned with ethyl acetate of P. aculeata aerial parts (HEPa/EtOAc) in mice fed a high-fat diet that share many obesity phenotypes with humans were evaluated. The animals were treated orally with HEPa/EtOAc (125 and 250 mg/kg/day) and pioglitazone (5 mg/kg/day), for 16 days. After the treatment, HEPa/EtOAc reduced fasting serum glucose and insulin levels, as well as homeostasis model assessment for insulin resistance. In addition, an improvement in glucose intolerance was also observed. Indeed, a reduction in the circulating levels of TNF-α and IL-6 was also observed. Furthermore, at molecular level, it was demonstrated that the HEPa/EtOAc treatment was able to improve these physiological parameters, through the activation of peroxisome proliferator-activated receptor γ (PPARγ) per si, as well as the enhancement of antioxidant mechanism by an increase in PPARγ/Cu(2+), Zn(2+)-superoxide dismutase (CuZn-SOD) axis expression in liver and adipose tissue. In sum, P. aculeata is effective to improve insulin resistance in a mouse model of obesity and this effect seems to involve the antioxidant and anti-inflammatory mechanisms through the increase in PPARγ/CuZn-SOD axis expression.

Salivary Antigen-5/CAP Family Members Are Cu2+-dependent Antioxidant Enzymes That Scavenge O2⨪ and Inhibit Collagen-induced Platelet Aggregation and Neutrophil Oxidative Burst*

PubMed Central

Assumpção, Teresa C. F.; Ma, Dongying; Schwarz, Alexandra; Reiter, Karine; Santana, Jaime M.; Andersen, John F.; Ribeiro, José M. C.; Nardone, Glenn; Yu, Lee L.; Francischetti, Ivo M. B.

2013-01-01

The function of the antigen-5/CAP family of proteins found in the salivary gland of bloodsucking animals has remained elusive for decades. Antigen-5 members from the hematophagous insects Dipetalogaster maxima (DMAV) and Triatoma infestans (TIAV) were expressed and discovered to attenuate platelet aggregation, ATP secretion, and thromboxane A2 generation by low doses of collagen (<1 μg/ml) but no other agonists. DMAV did not interact with collagen, glycoprotein VI, or integrin α2β1. This inhibitory profile resembles the effects of antioxidants Cu,Zn-superoxide dismutase (Cu,Zn-SOD) in platelet function. Accordingly, DMAV was found to inhibit cytochrome c reduction by O2⨪ generated by the xanthine/xanthine oxidase, implying that it exhibits antioxidant activity. Moreover, our results demonstrate that DMAV blunts the luminescence signal of O2⨪ generated by phorbol 12-myristate 13-acetate-stimulated neutrophils. Mechanistically, inductively coupled plasma mass spectrometry and fluorescence spectroscopy revealed that DMAV, like Cu,Zn-SOD, interacts with Cu2+, which provides redox potential for catalytic removal of O2⨪. Notably, surface plasmon resonance experiments (BIAcore) determined that DMAV binds sulfated glycosaminoglycans (e.g. heparin, KD ∼100 nmol/liter), as reported for extracellular SOD. Finally, fractions of the salivary gland of D. maxima with native DMAV contain Cu2+ and display metal-dependent antioxidant properties. Antigen-5/CAP emerges as novel family of Cu2+-dependent antioxidant enzymes that inhibit neutrophil oxidative burst and negatively modulate platelet aggregation by a unique salivary mechanism. PMID:23564450

Cerebellar Expression of Copper Chaperone for Superoxide, Cytosolic Cu/Zn-Superoxide Dismutase, 4-Hydroxy-2-Nonenal, Acrolein and Heat Shock Protein 32 in Patients with Menkes Kinky Hair Disease: Immunohistochemical Study

PubMed Central

Yokoyama, Atsushi; Ohno, Kousaku; Hirano, Asao; Shintaku, Masayuki; Kato, Masako; Hayashi, Kazuhiko; Kato, Shinsuke

2014-01-01

Background To clarify the pathogenesis of cerebellar Purkinje cell death in patients with Menkes kinky hair disease (MD), a disorder of copper absorption, we investigated the morphological and functional abnormalities of residual Purkinje cells in MD patients and the mechanism of cell death. Methods Seven MD patients and 39 neurologically normal autopsy cases were studied. We performed histopathological and quantitative analyses of the Purkinje cells. In addition, we used immunohistochemistry to detect copper-dependent enzymes [cytosolic Cu/Zn-superoxide dismutase (SOD1) and copper chaperone for superoxide dismutase (CCS)], oxidative stress markers [4-hydroxy-2-nonenal (HNE) and acrolein] and heat shock protein 32 (hsp 32). Results The surviving MD Purkinje cells showed abnormal development, such as somatic sprouts and heterotopic location. Due to maldevelopment and degeneration, dendrites showed the cactus and weeping willow patterns. Axonal degeneration led to the formation of torpedoes. Quantitative analysis revealed loss of approximately 50% of the Purkinje cells in MD patients. Almost all of the normal Purkinje cells were positive for immunostaining by anti-CCS and anti-SOD1 antibodies, with staining of the cell bodies, dendrites and axons. Normal Purkinje cells were not stained by antibodies for HNE, acrolein or hsp 32. In MD patients, the majority of Purkinje cells were positive for CCS, but the positive rate for SOD1 was only about 23%. Approximately 56%, 42% and 40% of the Purkinje cells of MD patients were positive for HNE, acrolein and hsp 32, respectively. Conclusion In MD patients, about 50% of the Purkinje cells have been lost due to maldevelopment and degeneration. In the residual Purkinje cells, CCS expression seems to be nearly normal as a protective response to decreased SOD1 activity due to copper deficiency. Because oxidative stress is elevated secondary to decreased SOD1 activity, hsp 32 is induced as another protective mechanism. PMID:25067875

Cerebellar expression of copper chaperone for superoxide, cytosolic cu/zn-superoxide dismutase, 4-hydroxy-2-nonenal, acrolein and heat shock protein 32 in patients with menkes kinky hair disease: immunohistochemical study.

PubMed

Yokoyama, Atsushi; Ohno, Kousaku; Hirano, Asao; Shintaku, Masayuki; Kato, Masako; Hayashi, Kazuhiko; Kato, Shinsuke

2014-03-01

To clarify the pathogenesis of cerebellar Purkinje cell death in patients with Menkes kinky hair disease (MD), a disorder of copper absorption, we investigated the morphological and functional abnormalities of residual Purkinje cells in MD patients and the mechanism of cell death. Seven MD patients and 39 neurologically normal autopsy cases were studied. We performed histopathological and quantitative analyses of the Purkinje cells. In addition, we used immunohistochemistry to detect copper-dependent enzymes [cytosolic Cu/Zn-superoxide dismutase (SOD1) and copper chaperone for superoxide dismutase (CCS)], oxidative stress markers [4-hydroxy-2-nonenal (HNE) and acrolein] and heat shock protein 32 (hsp 32). The surviving MD Purkinje cells showed abnormal development, such as somatic sprouts and heterotopic location. Due to maldevelopment and degeneration, dendrites showed the cactus and weeping willow patterns. Axonal degeneration led to the formation of torpedoes. Quantitative analysis revealed loss of approximately 50% of the Purkinje cells in MD patients. Almost all of the normal Purkinje cells were positive for immunostaining by anti-CCS and anti-SOD1 antibodies, with staining of the cell bodies, dendrites and axons. Normal Purkinje cells were not stained by antibodies for HNE, acrolein or hsp 32. In MD patients, the majority of Purkinje cells were positive for CCS, but the positive rate for SOD1 was only about 23%. Approximately 56%, 42% and 40% of the Purkinje cells of MD patients were positive for HNE, acrolein and hsp 32, respectively. In MD patients, about 50% of the Purkinje cells have been lost due to maldevelopment and degeneration. In the residual Purkinje cells, CCS expression seems to be nearly normal as a protective response to decreased SOD1 activity due to copper deficiency. Because oxidative stress is elevated secondary to decreased SOD1 activity, hsp 32 is induced as another protective mechanism.

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

PubMed Central

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

2013-01-01

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

Astaxanthin intake attenuates muscle atrophy caused by immobilization in rats.

PubMed

Shibaguchi, Tsubasa; Yamaguchi, Yusuke; Miyaji, Nobuyuki; Yoshihara, Toshinori; Naito, Hisashi; Goto, Katsumasa; Ohmori, Daijiro; Yoshioka, Toshitada; Sugiura, Takao

2016-08-01

Astaxanthin is a carotenoid pigment and has been shown to be an effective inhibitor of oxidative damage. We tested the hypothesis that astaxanthin intake would attenuate immobilization-induced muscle atrophy in rats. Male Wistar rats (14-week old) were fed for 24 days with either astaxanthin or placebo diet. After 14 days of each experimental diet intake, the hindlimb muscles of one leg were immobilized in plantar flexion position using a plaster cast. Following 10 days of immobilization, both the atrophic and the contralateral plantaris muscles were removed and analyzed to determine the level of muscle atrophy along with measurement of the protein levels of CuZn-superoxide dismutase (CuZn-SOD) and selected proteases. Compared with placebo diet animals, the degree of muscle atrophy in response to immobilization was significantly reduced in astaxanthin diet animals. Further, astaxanthin supplementation significantly prevented the immobilization-induced increase in the expression of CuZn-SOD, cathepsin L, calpain, and ubiquitin in the atrophied muscle. These results support the postulate that dietary astaxanthin intake attenuates the rate of disuse muscle atrophy by inhibiting oxidative stress and proteolysis via three major proteolytic pathways. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Mining the enzymes involved in the detoxification of reactive oxygen species (ROS) in sugarcane.

PubMed

Kurama, Eiko E; Fenille, Roseli C; Rosa, Vicente E; Rosa, Daniel D; Ulian, Eugenio C

2002-07-01

Summary Adopting the sequencing of expressed sequence tags (ESTs) of a sugarcane database derived from libraries induced and not induced by pathogens, we identified EST clusters homologous to genes corresponding to enzymes involved in the detoxification of reactive oxygen species. The predicted amino acids of these enzymes are superoxide dismutases (SODs), glutathione-S-transferase (GST), glutathione peroxidase (GPX), and catalases. Three MnSOD mitochondrial precursors and 10 CuZnSOD were identified in sugarcane: the MnSOD mitochondrial precursor is 96% similar to the maize MnSOD mitochondrial precursor and, of the 10 CuZnSOD identified, seven were 98% identical to maize cytosolic CuZnSOD4 and one was 67% identical to putative peroxisomal CuZnSOD from Arabidopsis. Three homologues to class Phi GST were 87-88% identical to GST III from maize. Five GPX homologues were identified: three were homologous to cytosolic GPX from barley, one was 88% identical to phospholipid hydroperoxide glutathione peroxidase (PHGPX) from rice, and the last was 71% identical to GPX from A. thaliana. Three enzymes similar to maize catalase were identified in sugarcane: two were similar to catalase isozyme 3 and catalase chain 3 from maize, which are mitochondrial, and one was similar to catalase isozyme 1 from maize, whose location is peroxisomal subcellular. All enzymes were induced in all sugarcane libraries (flower, seed, root, callus, leaves) and also in the pathogen-induced libraries, except for CuZnSOD whose cDNA was detected in none of the libraries induced by pathogens (Acetobacter diazotroficans and Herbaspirillum rubrisubalbicans). The expression of the enzymes SOD, GST, GPX, and catalases involved in the detoxification was examined using reverse transcriptase-polymerase chain reaction in cDNA from leaves of sugarcane under biotic stress conditions, inoculated with Puccinia melanocephala, the causal agent of sugarcane rust disease.

Reactive oxygen species on bone mineral density and mechanics in Cu,Zn superoxide dismutase (Sod1) knockout mice

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

Smietana, Michael J.; Arruda, Ellen M.; Mechanical Engineering, University of Michigan, 2250 GG Brown, 2350 Hayward, Ann Arbor, MI 48109

Research highlights: {yields} Reactive oxygen species (ROS) are considered to be a factor in the onset of a number of age-associated conditions, including loss of BMD. {yields} Cu,Zn-superoxide dismutase (Sod1) deficient mice have increased ROS, reduced bone mineral density, decreased bending stiffness, and decreased strength compared to WT controls. {yields} Increased ROS caused by the deficiency of Sod1, may be responsible for the changes in BMD and bone mechanics and therefore represent an appropriate model for studying mechanisms of age-associated bone loss. -- Abstract: Reactive oxygen species (ROS) play a role in a number of degenerative conditions including osteoporosis. Micemore » deficient in Cu,Zn-superoxide dismutase (Sod1) (Sod1{sup -/-} mice) have elevated oxidative stress and decreased muscle mass and strength compared to wild-type mice (WT) and appear to have an accelerated muscular aging phenotype. Thus, Sod1{sup -/-} mice may be a good model for evaluating the effects of free radical generation on diseases associated with aging. In this experiment, we tested the hypothesis that the structural integrity of bone as measured by bending stiffness (EI; N/mm{sup 2}) and strength (MPa) is diminished in Sod1{sup -/-} compared to WT mice. Femurs were obtained from male and female WT and Sod1{sup -/-} mice at 8 months of age and three-point bending tests were used to determine bending stiffness and strength. Bones were also analyzed for bone mineral density (BMD; mg/cc) using micro-computed tomography. Femurs were approximately equal in length across all groups, and there were no significant differences in BMD or EI with respect to gender in either genotype. Although male and female mice demonstrated similar properties within each genotype, Sod1{sup -/-} mice exhibited lower BMD and EI of femurs from both males and females compared with gender matched WT mice. Strength of femurs was also lower in Sod1{sup -/-} mice compared to WT as well as between genders. These data indicate that increased oxidative stress, due to the deficiency of Sod1 is associated with decreased bone stiffness and strength and Sod1{sup -/-} mice may represent an appropriate model for studying disease processes in aging bone.« less

Optimization of dietary zinc for egg production and antioxidant capacity in Chinese egg-laying ducks fed a diet based on corn-wheat bran and soybean meal.

PubMed

Chen, W; Wang, S; Zhang, H X; Ruan, D; Xia, W G; Cui, Y Y; Zheng, C T; Lin, Y C

2017-07-01

The aim of this study was to evaluate the effect of zinc supplementation on productive performance and antioxidant status in laying ducks. Five-hundred-four laying ducks were divided into 7 treatments, each containing 6 replicates of 12 ducks. The ducks were caged individually and fed a corn-soybean meal and wheat bran basal diet (37 mg Zn/kg) or the basal diet supplemented with 15, 30, 45, 60, 75, or 90 mg Zn/kg (as zinc sulfate). During the early laying period of 10 d (daily egg production <80%), egg production, daily egg mass, and FCR increased quadratically with increasing dietary Zn levels (P < 0.05). The highest egg production and daily egg weight were obtained when 30 or 45 mg Zn/kg diet was supplemented, with lowest FCR. Similarly, the highest egg production and daily egg mass were observed in the group supplemented with 30 or 45 mg Zn/kg during the peak laying period of the subsequent 120 d (daily egg production >80%). Average egg weight and feed intake did not differ among the groups of graded Zn supplementation.The egg quality was not affected by dietary Zn, including the egg shape index, Haugh unit, yolk color score, egg composition, and shell thickness. The activities of plasma activities of total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-PX) increased in a quadratic manner (P < 0.001) with increasing supplemental Zn. Plasma concentration of Zn increased quadratically (P < 0.05) as dietary Zn increased. The hepatic activity of Cu/Zn-SOD and GSH-PX increased quadratically (P < 0.05) with increasing dietary Zn. Plasma Zn concentrations were positively correlated with activities of T-SOD (P < 0.05), and positively with plasma Cu. Plasma concentration of reduced glutathione was correlated with plasma Cu. In conclusion, supplementation of Zn at 30 or 45 mg/kg to a corn-wheat bran and soybean basal diet may improve the productive performance and enhance the antioxidant capacity. © 2017 Poultry Science Association Inc.

Differences in seminal plasma and spermatozoa antioxidative systems and seminal plasma lipid and protein levels among boar breeds and hybrid genetic traits.

PubMed

Žura Žaja, Ivona; Samardžija, Marko; Vince, Silvijo; Vilić, Marinko; Majić-Balić, Ivanka; Đuričić, Dražen; Milinković-Tur, Suzana

2016-07-01

The objectives of this study were to determine the influence of breed and hybrid genetic traits of boars on lipid and protein concentrations and antioxidative system variables in seminal plasma (SP) and spermatozoa and their correlations with semen quality variables. Semen samples from 27 boars: Swedish Landraces (SL), German Landraces (GL), Large Whites (LW), Pietrains (P) and Pig Improvement Company hybrids (PIC-hybrid), aged from 1.5 to 3 years old, were collected. SP was spectrophotometrically analyzed to determine total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), triacylglycerol (TAG), total protein (TP), albumin, and zinc concentrations. The antioxidative system in SP and spermatozoa was established spectrophotometrically by determining total antioxidative status (TAS), total superoxide dismutase (TSOD) and glutathione peroxidase (GSH-Px) parameters, as well as copper-zinc superoxide dismutase (CuZnSOD) and manganese superoxide dismutase (MnSOD) activity in spermatozoa. The hybrid boars had higher (P<0.05) SP concentrations of: TC, LDL-C and TAG than P and GL; HDL-C than P, GL and SL; and TP than P and LW. PIC-hybrid had lower values (P<0.05) in spermatozoa of: TAS and CuZnSOD than SL; TSOD and GSH-Px than SL and P; and MnSOD than SL and LW. Differences in SP and spermatozoa antioxidative system variables and the significant differences in SP protein and lipid variables exist among boars of different breeds and hybrid. Novel data and observed differences in semen variables among boar breeds and hybrids and their correlations with semen quality parameters in this study could contribute to better assessment of boar semen quality. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative Analyses of Cu-Zn Superoxide Dismutase (SOD1) and Thioredoxin Reductase (TrxR) at the mRNA Level between Apis mellifera L. and Apis cerana F. (Hymenoptera: Apidae) Under Stress Conditions.

PubMed

Koo, Hyun-Na; Lee, Soon-Gyu; Yun, Seung-Hwan; Kim, Hyun Kyung; Choi, Yong Soo; Kim, Gil-Hah

2016-01-01

This study compared stress-induced expression of Cu-Zn superoxide dismutase (SOD1) and thioredoxin reductase (TrxR) genes in the European honeybee Apis mellifera L. and Asian honeybee Apis cerana F. Expression of both SOD1 and TrxR rapidly increased up to 5 h after exposure to cold (4 °C) or heat (37 °C) treatment and then gradually decreased, with a stronger effect induced by cold stress in A. mellifera compared with A. cerana. Injection of stress-inducing substances (methyl viologen, [MV] and H2O2) also increased SOD1 and TrxR expression in both A. mellifera and A. cerana, and this effect was more pronounced with MV than H2O2. Additionally, we heterologously expressed the A. mellifera and A. cerana SOD1 and TrxR proteins in an Escherichia coli expression system, and detection by SDS-PAGE, confirmed by Western blotting using anti-His tag antibodies, revealed bands at 16 and 60 kDa, respectively. Our results show that the expression patterns of SOD1 and TrxR differ between A. mellifera and A. cerana under conditions of low or high temperature as well as oxidative stress. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

Replacement of buried cysteine from zebrafish Cu/Zn superoxide dismutase and enhancement of its stability via site-directed mutagenesis.

PubMed

Ken, Chuian-Fu; Lin, Chi-Tsai; Wen, Yu-Der; Wu, Jen-Leih

2007-01-01

Zebrafish Cu/Zn-superoxide dismutase (ZSOD1) has one free cysteine (Cys-7) in a first beta-strand with lower thermostability. We predicted the stability would be increased with single-point mutation at 70 degrees C via the I-Mutant 2.0 server, and generated a mutant SOD with replacement of the free Cys to Ala (ZSODC7A) by site-directed mutagenesis. The mutant was expressed and purified from the Escherichia coli strain AD494(DE3)pLysS and the yield was 2 mg from 0.4 L of culture. The ZSODC7A was heated at 90 degrees C. In a time-dependent assay, the time interval for 50% inactivation was 32 min, and its thermal inactivation rate constant K (d) was 2 x 10(-2) min(-1). The mutant was still activated in broad pH range (2.3-12), and had only a moderate effect under sodium dodecyl sulfate treatment. The calculated specific activity of the mutant was 3980 U/mg, twice that of wild-type ZSOD1. In addition, we soaked fish larva with equal enzyme units of either ZSOD1 or ZSODC7A for 2 h, and then stressed them with 100 ppm of paraquat to induce oxidative injury. The survival rate was significant.

Isoenzymes of superoxide dismutase in nodules of Phaseolus vulgaris L. , Pisum sativum L. , and Vigna unguiculata (L. ) Walp

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

Becana, M.; Paris, F.J.; Sandalio, L.M.

1989-08-01

The activity and isozymic composition of superoxide dismutase were determined in nodules of Phaseolus vulgaris L., Pisum sativum L., and Vigna unguiculata (L.) Walp. A Mn-SOD was present in Rhizobium and two in Bradyrhizobium and bacteroids. Nodule mitochondria from all three legume species had a single Mn-SOD with similar relative mobility, whereas the cytosol contained several CuZn-SODs: two in Phaseolus and Pisum, and four in Vigna. In the cytoplasm of V. unguiculata nodules, a Fe-containing SOD was also present, with an electrophoretic mobility between those of CuZn- and Mn-SODs, and an estimated molecular weight of 57,000. Total SOD activity ofmore » the soluble fraction of host cells, expressed on a nodule fresh weight basis, exceeded markedly that of bacteroids. Likewise, specific SOD activities of free-living bacteria were superior or equal to those of their symbiotic forms. Soluble extracts of bacteria and bacteroids did not show peroxidase activity, but the nodule cell cytoplasm contained diverse peroxidase isozymes which were readily distinguishable from leghemoglobin components by electrophoresis. Data indicated that peroxidases and leghemoglobins did not significantly interfere with SOD localization on gels. Treatment with chloroform-ethanol scarcely affected the isozymic pattern of SODs and peroxidases, and had limited success in the removal of leghemoglobin.« less

Studies on glyphosate-induced carcinogenicity in mouse skin: a proteomic approach.

PubMed

George, Jasmine; Prasad, Sahdeo; Mahmood, Zafar; Shukla, Yogeshwer

2010-03-10

Glyphosate is a widely used broad spectrum herbicide, reported to induce various toxic effects in non-target species, but its carcinogenic potential is still unknown. Here we showed the carcinogenic effects of glyphosate using 2-stage mouse skin carcinogenesis model and proteomic analysis. Carcinogenicity study revealed that glyphosate has tumor promoting activity. Proteomic analysis using 2-dimensional gel electrophoresis and mass spectrometry showed that 22 spots were differentially expressed (>2 fold) on glyphosate, 7, 12-dimethylbenz[a]anthracene (DMBA) and 12-O-tetradecanoyl-phorbol-13-acetate (TPA) application over untreated control. Among them, 9 proteins (translation elongation factor eEF-1 alpha chain, carbonic anhydrase III, annexin II, calcyclin, fab fragment anti-VEGF antibody, peroxiredoxin-2, superoxide dismutase [Cu-Zn], stefin A3, and calgranulin-B) were common and showed similar expression pattern in glyphosate and TPA-treated mouse skin. These proteins are known to be involved in several key processes like apoptosis and growth-inhibition, anti-oxidant responses, etc. The up-regulation of calcyclin, calgranulin-B and down-regulation of superoxide dismutase [Cu-Zn] was further confirmed by immunoblotting, indicating that these proteins can be good candidate biomarkers for skin carcinogenesis induced by glyphosate. Altogether, these results suggested that glyphosate has tumor promoting potential in skin carcinogenesis and its mechanism seems to be similar to TPA. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Organic zinc and copper supplementation on antioxidant protective mechanism and their correlation with sperm functional characteristics in goats.

PubMed

Narasimhaiah, M; Arunachalam, A; Sellappan, S; Mayasula, V K; Guvvala, P R; Ghosh, S K; Chandra, V; Ghosh, J; Kumar, H

2018-06-01

Trace minerals feeding had significant effects on sperm production and fertility with better absorption and proper utilization within the body for optimum reproductive function. Several studies have shown that more influenced trace elements in the diets of animals are copper (Cu) and zinc (Zn). Bucks showing deficiency of this mineral might affect the quality of semen production which in turn would affect the fertility. This experiment was thus designed to test the effects of organic Cu and Zn supplementation on antioxidants enzyme activities and sperm functional attributes in fresh semen of bucks. Forty bucks (n = 40, Aged 5 months) were assigned to ten groups of four animals in each group, supplemented (for a period of 8 months) with different levels of organic Zn: 20 mg (T2), 40 mg (T3) and 60 mg (T4), organic Cu: 12.5 mg (T5), 25 mg (T6), 37.5 mg (T7) and combined organic Zn and Cu: 20 + 12.5 mg (T8), 40 + 25 mg (T9), 60 + 37.5 mg (T10), respectively, per kg dry matter and no additional mineral diet (control; T1). One hundred and sixty semen samples were collected through electro-ejaculator and analysed for sperm quantity, quality, acrosome intactness and plasma membrane integrity and correlated with the catalase, superoxide dismutase, glutathione peroxidase and glutathione reductase enzyme activities in seminal plasma. The results indicated organic Cu and zinc supplemented bucks produced more sperm cells, had higher sperm concentrations, maintained higher (p < .01) sperm livability, plasma membrane and acrosome integrities, more motility and velocity. The increased antioxidant enzyme activities, reduced oxidative stress and lowered lipid peroxidation were positively correlated (p < .05) with the sperm functional attributes. In conclusion, organic Cu and Zn supplement to male goats showed protective roles against oxidative damage and maintained better fresh semen characteristics. © 2018 Blackwell Verlag GmbH.

Evolution of a plant-specific copper chaperone family for chloroplast copper homeostasis

DOE PAGES

Blaby-Haas, Crysten E.; Padilla-Benavides, Teresita; Stübe, Roland; ...

2014-12-02

Metallochaperones traffic copper (Cu +) from its point of entry at the plasma membrane to its destination. In plants, one destination is the chloroplast, which houses plastocyanin, a Cu-dependent electron transfer protein involved in photosynthesis. In this paper, we present a previously unidentified Cu + chaperone that evolved early in the plant lineage by an alternative-splicing event of the pre-mRNA encoding the chloroplast P-type ATPase in Arabidopsis 1 (PAA1). In several land plants, recent duplication events created a separate chaperone-encoding gene coincident with loss of alternative splicing. The plant-specific Cu + chaperone delivers Cu + with specificity for PAA1, whichmore » is flipped in the envelope relative to prototypical bacterial ATPases, compatible with a role in Cu + import into the stroma and consistent with the canonical catalytic mechanism of these enzymes. The ubiquity of the chaperone suggests conservation of this Cu +-delivery mechanism and provides a unique snapshot into the evolution of a Cu + distribution pathway. Finally, we also provide evidence for an interaction between PAA2, the Cu +-ATPase in thylakoids, and the Cu +-chaperone for Cu/Zn superoxide dismutase (CCS), uncovering a Cu + network that has evolved to fine-tune Cu + distribution.« less

Decreased Nephrin and GLEPP-1, But Increased VEGF, Flt-1, and Nitrotyrosine, Expressions in Kidney Tissue Sections From Women With Preeclampsia

PubMed Central

Zhao, Shuang; Gu, Xin; Groome, Lynn J.; Wang, Yuping

2011-01-01

Renal injury is a common pathophysiological feature in women with preeclampsia as evidenced by increased protein leakage (proteinuria) and glomerular injury (glomerular endotheliosis). Recently, podocyturia was found in preeclampsia, suggesting podocyte shedding occurs in this pregnancy disorder. However, podocyte function in preeclampsia is poorly understood. In this study, the authors have examined podocyte-specific protein expressions for nephrin, glomerular epithelial protein 1 (GLEPP-1), and ezrin in kidney biopsy tissue sections from women with preeclampsia. Expressions for vascular endothelial growth factor (VEGF) and its receptor Flt-1 and oxidative stress marker nitrotyrosine and antioxidant CuZn-superoxide dismutase (CuZn-SOD) were also examined. Kidney tissue sections from nonhypertensive and chronic hypertensive participants were stained as controls. The findings were (1) nephrin and GLEPP-1 were mainly expressed in glomerular podocytes; (2) ezrin was expressed in both glomerular podocytes and tubular epithelial cells; (3) compared to tissue sections from nonhypertensive and chronic hypertensive participants, nephrin and GLEPP-1 expressions were much reduced in tissue sections from preeclampsia and ezrin expression was reduced in podocytes; (4) enhanced VEGF, Flt-1, and nitrotyrosine, but reduced CuZn-SOD, expressions were observed in both glomerular podocytes and endothelial cells in tissue sections from preeclampsia; and (5) the expression pattern for nephrin, GLEPP-1, ezrin, VEGF, Flt-1, and CuZn-SOD were similar between tissue sections from nonhypertensive and chronic hypertensive participants. Although the authors could not conclude from this biopsy study whether the podocyte injury is the cause or effect of the preeclampsia phenotype, the data provide compelling evidence that podocyte injury accompanied by altered angiogenesis process and increased oxidative stress occurs in kidney of patients with preeclampsia. PMID:19528353

Pro-inflammatory adipocytokines, oxidative stress, insulin, Zn and Cu: Interrelations with obesity in Egyptian non-diabetic obese children and adolescents.

PubMed

Habib, Salem A; Saad, Entsar A; Elsharkawy, Ashraf A; Attia, Zeinab R

2015-09-01

To investigate the inter-relationships between adipocytokines, oxidative stress, insulin, Zn and Cu and obesity among Egyptian obese non-diabetic children and adolescents. 72 obese children and adolescents of both sexes (5-17 years) were recruited for the study. 40 healthy normal non-obese persons of matched ages and sexes were used as control group. Lipid profile, tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and leptin levels were measured. Malondialdehyde (MDA) and reduced glutathione (GSH) concentrations and superoxide dismutase (SOD) activity were estimated. Micronutrients (Zn and Cu) concentrations in addition to insulin and fasting blood sugar (FBS) levels were also evaluated. Estimation of insulin resistance (homeostatic model assessment (HOMA-IR)) was derived from FBS measurements. Significant elevations (P<0.001) in TNF-α, IL-6, leptin, MDA, Cu and FBS levels and significant decreases (P<0.001) in GSH, Zn levels and SOD activity were detected among obese individuals as compared with control group. Insulin and triglyceride levels were significantly increased in obese male children and HDL-cholesterol level was increased significantly in obese adolescent females compared to controls. However, total cholesterol and LDL-cholesterol levels were significantly high in all obese cases as compared with controls. Insulin resistance was detected in 100% of the patients. We concluded that obesity with pro-inflammatory adipocytokines and hypozincemia together by many mechanisms participate in excessive oxidative stress and are highly associated with inflammation and the development of obesity-related complications. Obesity represents a critical risk factor for development of insulin resistance status. Copyright © 2015 Medical University of Bialystok. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

[Oxidative Stress Level of Vanadium-exposed Workers].

PubMed

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

2015-11-01

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

Transduced human copper chaperone for Cu,Zn-SOD (PEP-1-CCS) protects against neuronal cell death.

PubMed

Choi, Soo Hyun; Kim, Dae Won; Kim, So Young; An, Jae Jin; Lee, Sun Hwa; Choi, Hee Soon; Sohn, Eun Jung; Hwang, Seok-Il; Won, Moo Ho; Kang, Tae-Cheon; Kwon, Hyung Joo; Kang, Jung Hoon; Cho, Sung-Woo; Park, Jinseu; Eum, Won Sik; Choi, Soo Young

2005-12-31

Reactive oxygen species (ROS) contribute to the development of various human diseases. Cu,Zn-superoxide dismutase (SOD) is one of the major means by which cells counteract the deleterious effects of ROS. SOD activity is dependent upon bound copper ions supplied by its partner metallochaperone protein, copper chaperone for SOD (CCS). In the present study, we investigated the protective effects of PEP-1-CCS against neuronal cell death and ischemic insults. When PEP-1-CCS was added to the culture medium of neuronal cells, it rapidly entered the cells and protected them against paraquat-induced cell death. Moreover, transduced PEP-1-CCS markedly increased endogenous SOD activity in the cells. Immunohistochemical analysis revealed that it prevented neuronal cell death in the hippocampus in response to transient forebrain ischemia. These results suggest that CCS is essential to activate SOD, and that transduction of PEP-1-CCS provides a potential strategy for therapeutic delivery in various human diseases including stroke related to SOD or ROS.

Effect of Concentrated Apple Extract on Experimental Colitis Induced by Acetic Acid.

PubMed

Pastrelo, Maurício Mercaldi; Dias Ribeiro, Carla Caroline; Duarte, Joselmo Willamys; Bioago Gollücke, Andréa Pitelli; Artigiani-Neto, Ricardo; Ribeiro, Daniel Araki; Miszputen, Sender Jankiel; Fujiyama Oshima, Celina Tizuko; Ribeiro Paiotti, Ana Paula

2017-01-01

Reactive oxygen and nitrogen species (ROS/RNS) play a crucial role in inflammatory bowel disease (IBD) exacerbating the chronic inflammatory process. Endogenous and diet antioxidants can neutralize these compounds. The apple is widely consumed, with several antioxidant activity compounds. The present study evaluated the effects of concentrated apple extract (CAE) in acetic acid induced colitis. 29 Wistar male rats were randomized into 5 groups. G1-Sham/saline solution, G2-CAE/control, G3-acetic acid/control, G4-curative- CAE treatment and G5-preventive-CAE treatment. Eight days later, the animals were euthanized and the colonic segment resected for macroscopic and histological analysis. Gene expression was evaluated for inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), catalase and copper and zinc superoxide dismutase (CuZnSOD) by quantitative real time PCR, while protein expression was assessed for iNOS, COX-2 and 8-hydroxy-20-deoxyguanosine (8-OHdG) via immunohistochemistry. The groups G3, G4 and G5 had weight loss, while G5 had weight increase at the end of the experiment. The treatment with CAE reduced the macroscopic and microscopic injury, decreased iNOS mRNA expression and increased CuZnSOD mRNA expression in animals with induced acetic acid-colitis. The findings of the present study suggest that CAE treatment exerts an antioxidant role by downregulating iNOS and upregulating CuZnSOD.

Sleep deprivation alters gene expression and antioxidant enzyme activity in mice splenocytes.

PubMed

Lungato, L; Marques, M S; Pereira, V G; Hix, S; Gazarini, M L; Tufik, S; D'Almeida, V

2013-03-01

Cellular defence against the formation of reactive oxygen species (ROS) involves a number of mechanisms in which antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD) play an important role. The relation between sleep deprivation and oxidative stress has not yet been completely elucidated. Although some authors did not find evidence of this relationship, others found alterations in some oxidative stress markers in response to sleep deprivation. Thus, the objective of this study was to identify changes induced by sleep deprivation in the activity and gene expression of antioxidant enzymes in mice splenocytes, ideally corroborating a better understanding of the observed effects related to sleep deprivation, which could be triggered by oxidative imbalance. Splenocytes from mice sleep deprived for 72 h showed no significant difference in CAT and CuZnSOD gene expression compared with normal sleep mice. However, sleep-deprived mice did show higher MnSOD gene expression than the control group. Concerning enzymatic activity, CuZnSOD and MnSOD significantly increased after sleep deprivation, despite the expression in CuZnSOD remained unchanged. Moreover, CAT activity was significantly lower after sleep deprivation. The data suggest that the antioxidant system is triggered by sleep deprivation, which in turn could influence the splenocytes homoeostasis, thus interfering in physiological responses. © 2013 The Authors. Scandinavian Journal of Immunology © 2013 Blackwell Publishing Ltd.

Sperm antioxidant defences decrease during epididymal transit from caput to cauda in parallel with increases in epididymal fluid in the goat (Capra hircus).

PubMed

Rana, Mashidur; Roy, Sudhir C; Divyashree, Bannur C

2017-09-01

The status of antioxidant defences of both spermatozoa and their associated fluids during epididymal transit from the caput to cauda have not been studied so far in any species. Herein we report for the first time that sperm antioxidant defences, namely Cu,Zn-superoxide dismutase (Cu,Zn-SOD) and catalase activity, decrease significantly (P<0.05) from the caput to cauda during epididymal transit in parallel with increases in Cu,Zn-SOD, total SOD and total glutathione peroxidase (GPx) activity in the luminal fluid of the respective segments. However, levels of GPX1 and GPX3 in epididymal fluid did not change significantly from the caput to cauda. Catalase was detected for the first time in goat spermatozoa. A significantly higher total antioxidant capacity of caudal fluid than of the caput suggests a requirement for a rich antioxidant environment for the storage of spermatozoa. The retention of cytoplasmic droplets in most of the caudal spermatozoa confirmed that these droplets do not contribute to the increased antioxidant defences of cauda epididymidal fluid. Thus, the antioxidant defences of the spermatozoa and their associated epididymal fluid are modulated from the caput to cauda in a region-specific manner. This may be one of the compensatory mechanisms of epididymal fluid to scavenge any excess reactive oxygen species produced in the microenvironment of spermatozoa.

Intravenous superoxide dismutase as a protective agent to prevent impairment of lung function induced by high tidal volume ventilation.

PubMed

Wu, Nan-Chun; Liao, Fan-Ting; Cheng, Hao-Min; Sung, Shih-Hsien; Yang, Yu-Chun; Wang, Jiun-Jr

2017-07-26

Positive-pressure mechanical ventilation is essential in assisting patients with respiratory failure in the intensive care unit and facilitating oxygenation in the operating room. However, it was also recognized as a primary factor leading to hospital-acquired pulmonary dysfunction, in which pulmonary oxidative stress and lung inflammation had been known to play important roles. Cu/Zn superoxide dismutase (SOD) is an important antioxidant, and possesses anti-inflammatory capacity. In this study, we aimed to study the efficacy of Cu/Zn SOD, administered intravenously during high tidal volume (HTV) ventilation, to prevent impairment of lung function. Thirty-eight male Sprague-Dawley rats were divided into 3 groups: 5 h ventilation with (A) low tidal volume (LTV; 8 mL/kg; n = 10), (B) high tidal volume (HTV; 18 mL/kg; n = 14), or (C) HTV and intravenous treatment of Cu/Zn SOD at a dose of 1000 U/kg/h (HTV + SOD; n = 14). Lung function was evaluated both at baseline and after 5-h ventilation. Lung injury was assessed by histological examination, lung water and protein contents in the bronchoalveolar lavage fluid (BALF). Pulmonary oxidative stress was examined by concentrations of methylguanidine (MG) and malondialdehyde (MDA) in BALF, and antioxidative activity by protein expression of glutathione peroxidase-1 (GPx-1) in the lung. Severity of lung inflammation was evaluated by white blood cell and differential count in BALF, and protein expression of inducible nitric oxide synthase (iNOS), intercellular adhesion molecule-1 (ICAM-1), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9), and mRNA expression of nuclear factor-κB (NF-κB) in the lung. We also examined protein expression of surfactant protein (SP)-A and D and we measured hourly changes in serum nitric oxide (NO) level. Five hours of LTV ventilation did not induce a major change in lung function, whereas 5 h of HTV ventilation induced apparent combined restrictive and obstructive lung disorder, together with increased pulmonary oxidative stress, decreased anti-oxidative activity and increased lung inflammation (P < 0.05). HTV ventilation also decreased SP-A and SP-D expression and suppressed serum NO level during the time course of ventilation. Cu/Zn SOD administered intravenously during HTV ventilation effectively reversed associated pulmonary oxidative stress and lung inflammation (P < 0.05); moreover, it preserved SP-A and SP-D expressions in the lung and increased serum nitric oxide (NO) level, enhancing vascular NO bioavailability. HTV ventilation can induce combined restrictive and obstructive lung disorders. Intravenous administration of Cu/Zn SOD during HTV ventilation can prevent lung function impairment and lung injury via reducing pulmonary oxidative stress and lung inflammation, preserving pulmonary surfactant expression, and enhancing vascular NO bioavailability.

Virtual electrochemical nitric oxide analyzer using copper, zinc superoxide dismutase immobilized on carbon nanotubes in polypyrrole matrix.

PubMed

Madasamy, Thangamuthu; Pandiaraj, Manickam; Balamurugan, Murugesan; Karnewar, Santosh; Benjamin, Alby Robson; Venkatesh, Krishna Arun; Vairamani, Kanagavel; Kotamraju, Srigiridhar; Karunakaran, Chandran

2012-10-15

In this work, we have designed and developed a novel and cost effective virtual electrochemical analyzer for the measurement of NO in exhaled breath and from hydrogen peroxide stimulated endothelial cells using home-made potentiostat. Here, data acquisition system (NI MyDAQ) was used to acquire the data from the electrochemical oxidation of NO mediated by copper, zinc superoxide dismutase (Cu,ZnSOD). The electrochemical control programs (graphical user-interface software) were developed using LabVIEW 10.0 to sweep the potential, acquire the current response and process the acquired current signal. The Cu,ZnSOD (SOD1) immobilized on the carbon nanotubes in polypyrrole modified platinum electrode was used as the NO biosensor. The electrochemical behavior of the SOD1 modified electrode exhibited the characteristic quasi-reversible redox peak at the potential, +0.06 V vs. Ag/AgCl. The biological interferences were eliminated by nafion coated SOD1 electrode and then NO was measured selectively. Further, this biosensor showed a wide linear range of response over the concentration of NO from 0.1 μM to 1 mM with a detection limit of 0.1 μM and high sensitivity of 1.1 μA μM(-1). The electroanalytical results obtained here using the developed virtual electrochemical instrument were also compared with the standard cyclic voltammetry instrument and found in agreement with each other. Copyright © 2012 Elsevier B.V. All rights reserved.

Cissus quadrangularis ethanol extract upregulates superoxide dismutase, glutathione peroxidase and endothelial nitric oxide synthase expression in hydrogen peroxide-injured human ECV304 cells.

PubMed

Sapsrithong, Tarat; Kaewprem, Weeraya; Tongumpai, Sarunya; Nusuetrong, Punnee; Meksuriyen, Duangdeun

2012-09-28

Cissus quadrangularis has been widely used in traditional medicine for the treatment of hemorrhoid. However, the detailed mechanism of antioxidant defense of C. quadrangularis in endothelial cells under oxidative stress remains unclear. The present study aims to elucidate the protective role of ethanol extract of C. quadrangularis (CQE) including its constituents, quercetin and resveratrol, on hydrogen peroxide (H(2)O(2))-injured human umbilical vein endothelial ECV304 cells. Viability, genotoxicity and protein expression of ECV304 cells were analyzed by MTT, alkaline comet and Western blot, respectively. Production of intracellular reactive oxygen species (ROS) was determined using dichlorofluorescein fluorescence dye. After exposing cells to CQE containing quercetin and resveratrol, DNA damage was not observed. CQE including quercetin and resveratrol significantly attenuated ROS in H(2)O(2)-injured ECV304 cells in a concentration-dependent manner. The protein expression of superoxide dismutase (Cu/Zn-SOD, Mn-SOD), glutathione peroxidase (GPx) and endothelial nitric oxide synthase (eNOS) increased in the cells treated with CQE, quercetin or resveratrol prior to H(2)O(2) exposure, as compared with control. The results provide a molecular mechanism of C. quadrangularis, which could be partially related to quercetin and resveratrol, in restoring ROS in endothelial cells through the upregulation of Cu/Zn-SOD, Mn-SOD, GPx and eNOS. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

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

PubMed

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

2003-01-01

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

Age-related differences of semen quality, seminal plasma, and spermatozoa antioxidative and oxidative stress variables in bulls during cold and warm periods of the year.

PubMed

Vince, S; Žura Žaja, I; Samardžija, M; Majić Balić, I; Vilić, M; Đuričić, D; Valpotić, H; Marković, F; Milinković-Tur, S

2018-03-01

The aims of this study were to determine the presence and quantities of antioxidative status and oxidative stress (OS) variables in the seminal plasma and spermatozoa of bulls of varying age during cold and warm periods of the year, and to establish the correlation of these variables with semen quality parameters. The study was conducted on two groups each comprising nine Simmental bulls: one group contained younger animals (aged 2 to 4 years) and the second older animals (aged 5 to 10 years). Semen samples were collected using an artificial vagina for biochemical analysis. Seminal plasma and spermatozoa activities of total superoxide dismutase (TSOD), manganese superoxide dismutase (MnSOD), copper-zinc superoxide dismutase (CuZnSOD), catalase (CAT), selenium-dependent glutathione peroxidase, reduced glutathione and concentrations of total protein (TP), thiobarbituric acid reactive substances (TBARS) and protein carbonyl content (PCC) were determined. Several antioxidants in seminal plasma were also determined: total glutathione peroxidase (TGSH-Px), selenium-independent glutathione peroxidase (Non-SeGSH-Px), uric acid, albumins (ALB) and alkaline phosphatase (ALP). Significantly higher spermatozoa motility was observed during the cold v. warm period, and a significantly higher volume and total number of spermatozoa per ejaculate was observed in older than in younger bulls. Significantly higher values of ALP, TP and ALB were found in seminal plasma of older bulls than in younger bulls during the warm period. The seminal plasma of younger bulls showed significantly higher activities of TSOD, MnSOD, CuZnSOD, TGSH-Px and Non-SeGSH-Px. Younger bulls had significantly higher PCC concentration and activity of CAT in seminal plasma than older bulls during the cold period. Significantly higher concentrations of PCC and TBARS, and activities of TSOD, MnSOD and CuZnSOD were established in spermatozoa of the younger than in older bulls during the warm period. It could be concluded that antioxidative and OS variables differ significantly depending on bull age and time of year. Younger bulls were more sensitive to elevated ambient temperatures during the warm period, when the higher enzymatic antioxidative protection in seminal plasma and spermatozoa were insufficient to counteract the intensive oxidative processes in spermatozoa, which eventually resulted in decreased spermatozoa motility. The estimation of antioxidative and OS variables in seminal plasma and spermatozoa may have practical value for the assessment of bull semen quality.

Superoxide and Peroxynitrite in Atherosclerosis

NASA Astrophysics Data System (ADS)

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

1994-02-01

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

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

PubMed Central

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

2013-01-01

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

Structural, Functional, and Immunogenic Insights on Cu,Zn Superoxide Dismutase Pathogenic Virulence Factors from Neisseria meningitidis and Brucella abortus

PubMed Central

Pratt, Ashley J.; DiDonato, Michael; Shin, David S.; Cabelli, Diane E.; Bruns, Cami K.; Belzer, Carol A.; Gorringe, Andrew R.; Langford, Paul R.; Tabatabai, Louisa B.; Kroll, J. Simon; Tainer, John A.

2015-01-01

ABSTRACT Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and health consequences. Superoxide dismutases are master regulators of reactive oxygen and general pathogenicity factors and are therefore therapeutic targets. Cu,Zn superoxide dismutases (SODs) localized to the periplasm promote survival by detoxifying superoxide radicals generated by major host antimicrobial immune responses. We discovered that passive immunization with an antibody directed at N. meningitidis SOD (NmSOD) was protective in a mouse infection model. To define the relevant atomic details and solution assembly states of this important virulence factor, we report high-resolution and X-ray scattering analyses of NmSOD and of SOD from B. abortus (BaSOD). The NmSOD structures revealed an auxiliary tetrahedral Cu-binding site bridging the dimer interface; mutational analyses suggested that this metal site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses informed us about electrostatic substrate guidance, dimer assembly, and an exposed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure provided insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes, and suggest general targets for antibacterial immune responses. The identified functional contributions, motifs, and targets distinguishing bacterial and eukaryotic SOD assemblies presented here provide a foundation for efforts to develop SOD-specific inhibitors of or vaccines against these harmful pathogens. IMPORTANCE By protecting microbes against reactive oxygen insults, SODs aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific differences relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of Neisseria meningitidis and Brucella abortus SODs, we used X-ray structures, enzymology, modeling, and murine infection experiments. We identified virulence determinants common to the two homologs, assembly differences, and a unique metal reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and a basis for SOD-specific drug design and an extension of immunogen design to target two important pathogens that continue to pose global health threats. PMID:26459556

Structural, Functional, and Immunogenic Insights on Cu,Zn Superoxide Dismutase Pathogenic Virulence Factors from Neisseria meningitidis and Brucella abortus.

PubMed

Pratt, Ashley J; DiDonato, Michael; Shin, David S; Cabelli, Diane E; Bruns, Cami K; Belzer, Carol A; Gorringe, Andrew R; Langford, Paul R; Tabatabai, Louisa B; Kroll, J Simon; Tainer, John A; Getzoff, Elizabeth D

2015-12-01

Bacterial pathogens Neisseria meningitidis and Brucella abortus pose threats to human and animal health worldwide, causing meningococcal disease and brucellosis, respectively. Mortality from acute N. meningitidis infections remains high despite antibiotics, and brucellosis presents alimentary and health consequences. Superoxide dismutases are master regulators of reactive oxygen and general pathogenicity factors and are therefore therapeutic targets. Cu,Zn superoxide dismutases (SODs) localized to the periplasm promote survival by detoxifying superoxide radicals generated by major host antimicrobial immune responses. We discovered that passive immunization with an antibody directed at N. meningitidis SOD (NmSOD) was protective in a mouse infection model. To define the relevant atomic details and solution assembly states of this important virulence factor, we report high-resolution and X-ray scattering analyses of NmSOD and of SOD from B. abortus (BaSOD). The NmSOD structures revealed an auxiliary tetrahedral Cu-binding site bridging the dimer interface; mutational analyses suggested that this metal site contributes to protein stability, with implications for bacterial defense mechanisms. Biochemical and structural analyses informed us about electrostatic substrate guidance, dimer assembly, and an exposed C-terminal epitope in the NmSOD dimer. In contrast, the monomeric BaSOD structure provided insights for extending immunogenic peptide epitopes derived from the protein. These collective results reveal unique contributions of SOD to pathogenic virulence, refine predictive motifs for distinguishing SOD classes, and suggest general targets for antibacterial immune responses. The identified functional contributions, motifs, and targets distinguishing bacterial and eukaryotic SOD assemblies presented here provide a foundation for efforts to develop SOD-specific inhibitors of or vaccines against these harmful pathogens. By protecting microbes against reactive oxygen insults, SODs aid survival of many bacteria within their hosts. Despite the ubiquity and conservation of these key enzymes, notable species-specific differences relevant to pathogenesis remain undefined. To probe mechanisms that govern the functioning of Neisseria meningitidis and Brucella abortus SODs, we used X-ray structures, enzymology, modeling, and murine infection experiments. We identified virulence determinants common to the two homologs, assembly differences, and a unique metal reservoir within meningococcal SOD that stabilizes the enzyme and may provide a safeguard against copper toxicity. The insights reported here provide a rationale and a basis for SOD-specific drug design and an extension of immunogen design to target two important pathogens that continue to pose global health threats. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

First-principles study of defect formation in a photovoltaic semiconductor Cu2ZnGeSe4

NASA Astrophysics Data System (ADS)

Nishihara, Hironori; Maeda, Tsuyoshi; Wada, Takahiro

2018-02-01

The formation energies of neutral Cu, Zn, Ge, and Se vacancies in kesterite-type Cu2ZnGeSe4 were evaluated by first-principles pseudopotential calculations using plane-wave basis functions. The calculations were performed at typical points in Cu-(Zn1/2Ge1/2)-Se and Cu3Se2-ZnSe-GeSe2 pseudoternary phase diagrams for Cu2ZnGeSe4. The results were compared with those for Cu2ZnSnSe4, Cu2ZnGeS4, and Cu2ZnSnS4 calculated using the same version of the CASTEP program code. The results indicate that Cu vacancies are easily formed in Cu2ZnGeSe4 under the Cu-poor condition as in the above compounds and CuInSe2, suggesting that Cu2ZnGeSe4 is also a preferable p-type absorber material for thin-film solar cells. The formation energies of possible antisite defects, such as CuZn and CuGe, and of possible complex defects, such as CuZn+ZnCu, were also calculated and compared within the above materials. The antisite defect of CuZn, which has the smallest formation energy within the possible defects, is concluded to be the most hardly formed in Cu2ZnGeSe4 among the compounds.

Short-term effects of sibutramine on mineral status and selected biochemical parameters in obese women.

PubMed

Suliburska, Joanna; Bogdański, Paweł; Szulińska, Monika; Pupek-Musialik, Danuta

2012-11-01

The aim of this study was to assess the effect of sibutramine on mineral status and selected biochemical parameters in obese women. The study was conducted on 24 patients who received 15 mg daily doses of sibutramine for 12 weeks, and on 20 patients who received placebo. At the baseline, after the sixth and twelfth weeks of treatment, body weight and blood pressure were measured, the BMI was calculated, and samples of blood and of first morning urine were collected. Serum lipid profiles, glucose levels, and nitric oxide levels were determined. The iron (Fe), copper (Cu), zinc (Zn), calcium (Ca), and magnesium (Mg) present in the serum and urine samples were assessed. The erythrocyte hemolysate of the patients was use to assay the activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD). No changes were observed in BMI, blood pressure, or nitric oxide during the study. After 12 weeks of treatment, a decrease was observed in total cholesterol, LDL cholesterol, triglyceride, glucose, and ferritin levels. GSH-Px and SOD activity increased after 12 weeks of sibutramine treatment. The Mg and Cu increases was observed in serum after the sixth and twelfth weeks of treatment. It was found that the Zn level decreased in serum after the twelfth week. The elimination of Ca, Mg, Fe, Zn, and Cu in urine also declined in the twelfth week. No differences were found in the women taking the placebo. In conclusion, we found that sibutramine had a positive effect on lipid and glucose status in obese women. However, the drug disturbed the balance of minerals, especially Zn and Mg, in the subjects.

Trace elements and antioxidant enzymes in Behçet's disease.

PubMed

Saglam, K; Serce, A F; Yilmaz, M I; Bulucu, F; Aydin, A; Akay, C; Sayal, A

2002-07-01

Free oxygen radicals and insufficiency of antioxidant enzymes have been implicated in the pathogenesis of Behçet's disease (BD). Trace elements function as cofactors to antioxidant enzymes. The antioxidant system and trace elements were investigated in many different studies, including BD, but these subjects have not been investigated as a whole in these patients. The aim of the present study was to investigate the antioxidative system and trace elements in BD to contribute to the knowledge of pathogenesis and treatment of this disease. We examined glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities together with selenium (Se), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) levels in plasma and erythrocytes of 50 patients with BD and 30 healthy controls. It was found that in patients with BD, erythrocyte GSH-Px and SOD activities and erythrocyte Se, plasma Fe, Mn, and Zn levels were significantly lower than those of controls and that plasma Cu, erythrocyte Zn, and Mn levels were significantly higher in patients with BD. Insufficient antioxidant enzyme activities were observed in patients with BD. The mechanism(s) of this phenomenon is not clear. Therefore, supplementation with trace elements involved in the antioxidative processes may increase scavenger enzyme activities, and consequently, an improvement in clinical symptoms may be expected.

Decreased erythrocyte CCS content is a biomarker of copper overload in rats.

PubMed

Bertinato, Jesse; Sherrard, Lindsey; Plouffe, Louise J

2010-07-02

Copper (Cu) is an essential trace metal that is toxic in excess. It is therefore important to be able to accurately assess Cu deficiency or overload. Cu chaperone for Cu/Zn superoxide dismutase (CCS) protein expression is elevated in tissues of Cu-deficient animals. Increased CCS content in erythrocytes is particularly sensitive to decreased Cu status. Given the lack of a non-invasive, sensitive and specific biomarker for the assessment of Cu excess, we investigated whether CCS expression in erythrocytes reflects Cu overload. Rats were fed diets containing normal or high levels of Cu for 13 weeks. Diets contained 6.3 +/- 0.6 (Cu-N), 985 +/- 14 (Cu-1000) or 1944 +/- 19 (Cu-2000) mg Cu/kg diet. Rats showed a variable response to the high Cu diets. Some rats showed severe Cu toxicity, while other rats showed no visible signs of toxicity and grew normally. Also, some rats had high levels of Cu in liver, whereas others had liver Cu concentrations within the normal range. Erythrocyte CCS protein expression was 30% lower in Cu-2000 rats compared to Cu-N rats (P < 0.05). Notably, only rats that accumulated high levels of Cu in liver had lower erythrocyte CCS (47% reduction, P < 0.05) compared to rats fed normal levels of Cu. Together, these data indicate that decreased erythrocyte CCS content is associated with Cu overload in rats and should be evaluated further as a potential biomarker for assessing Cu excess in humans.

Transcriptional analysis of disk abalone (Haliotis discus discus) antioxidant enzymes against marine bacteria and virus challenge.

PubMed

De Zoysa, Mahanama; Whang, Ilson; Nikapitiya, Chamilani; Oh, Chulhong; Choi, Cheol Young; Lee, Jehee

2011-07-01

Diverse antioxidant enzymes are essential for marine organisms to overcome oxidative stress as well as for the fine-tuning of immune reactions through activating different signal transduction pathways. This study describes the transcriptional analysis of antioxidant enzymes of disk abalone by challenging with bacteria (Vibrio alginolyticus, Vibrio parahemolyticus, and Listeria monocytogenes) and viral hemorrhagic septicemia virus (VHSV). Upon bacteria and VHSV challenge, Manganese superoxide dismutase (MnSOD), Copper, Zinc superoxide dismutase (CuZnSOD), catalase, thioredoxin peroxidase (TPx), Selenium-dependent glutathione peroxidase (SeGPx), and thioredoxin-2 (TRx-2) expression levels were altered in gills, and hemocytes at different magnitudes. In gills, only MnSOD, catalase, and SeGPx genes were completely upregulated by post-challenge of bacterial and VHSV. Among them, SeGPx demonstrated strong upregulation by 16-fold (bacteria) and 2-fold (VHSV) in gills, and 5-fold (bacteria) and 3.0-fold (VHSV) in hemocytes. None of the genes examined were downregulated (in gills and hemocytes) by bacteria challenge even though CuZnSOD and TPx showed downregulation (completely) in hemocytes by VHSV. In general, abalone hemocytes had lower potential to induce antioxidant enzyme transcripts upon bacteria and VHSV challenge than gills. Based upon these results, we suggest that abalones induce oxidative stress in tissues during the bacteria and VHSV challenge, and the identified response of antioxidant enzymes could be supported for maintaining a low-level of reactive oxygen species (ROS) that may serve as a signal for activating immune reactions against pathogenic conditions. Copyright © 2011 Elsevier Ltd. All rights reserved.

Cu, Zn-Superoxide Dismutase Increases the Therapeutic Potential of Adipose-derived Mesenchymal Stem Cells by Maintaining Antioxidant Enzyme Levels.

PubMed

Yoo, Dae Young; Kim, Dae Won; Chung, Jin Young; Jung, Hyo Young; Kim, Jong Whi; Yoon, Yeo Sung; Hwang, In Koo; Choi, Jung Hoon; Choi, Goang-Min; Choi, Soo Young; Moon, Seung Myung

2016-12-01

In the present study, we investigated the ability of Cu, Zn-superoxide dismutase (SOD1) to improve the therapeutic potential of adipose tissue-derived mesenchymal stem cells (Ad-MSCs) against ischemic damage in the spinal cord. Animals were divided into four groups: the control group, vehicle (PEP-1 peptide and artificial cerebrospinal fluid)-treated group, Ad-MSC alone group, and Ad-MSC-treated group with PEP-1-SOD1. The abdominal aorta of the rabbit was occluded for 30 min in the subrenal region to induce ischemic damage, and immediately after reperfusion, artificial cerebrospinal fluid or Ad-MSCs (2 × 10 5 ) were administered intrathecally. In addition, PEP-1 or 0.5 mg/kg PEP-1-SOD1 was administered intraperitoneally to the Ad-MSC-treated rabbits. Motor behaviors and NeuN-immunoreactive neurons were significantly decreased in the vehicle-treated group after ischemia/reperfusion. Administration of Ad-MSCs significantly ameliorated the changes in motor behavior and NeuN-immunoreactive neuronal survival. In addition, the combination of PEP-1-SOD1 and Ad-MSCs further increased the ameliorative effects of Ad-MSCs in the spinal cord after ischemia. Furthermore, the administration of Ad-MSCs with PEP-1-SOD1 decreased lipid peroxidation and maintained levels of antioxidants such as SOD1 and glutathione peroxidase compared to the Ad-MSC alone group. These results suggest that combination therapy using Ad-MSCs and PEP-1-SOD1 strongly protects neurons from ischemic damage by modulating the balance of lipid peroxidation and antioxidants.

Effect of Allium flavum L. and Allium melanantherum Panč. Extracts on Oxidative DNA Damage and Antioxidative Enzymes Superoxide Dismutase and Catalase.

PubMed

Mitić-Ćulafić, Dragana; Nikolić, Biljana; Simin, Nataša; Jasnić, Nebojša; Četojević-Simin, Dragana; Krstić, Maja; Knežević-Vukčević, Jelena

2016-03-01

Allium flavum L. and Allium melanantherum Panč. are wild growing plants used in traditional diet in Balkan region. While chemical composition and some biological activities of A. flavum have been reported, A. melanantherum, as an endemic in the Balkan Peninsula, has never been comprehensively examined. After chemical characterization of A. melanantherum, we examined the protective effect of methanol extracts of both species against t-butyl hydro-peroxide (t-BOOH)-induced DNA damage and mutagenesis. The bacterial reverse mutation assay was performed on Escherichia coli WP2 oxyR strain. DNA damage was monitored in human fetal lung fibroblasts (MRC-5) with alkaline comet assay. Obtained results indicated that extracts reduced t-BOOH-induced DNA damage up to 70 and 72% for A. flavum and A. melanantherum extract, respectively, and showed no effect on t-BOOH-induced mutagenesis. Since the results indicated modulatory effect on cell-mediated antioxidative defense, the effect of extracts on total protein content, and superoxide dismutase (SOD) and catalase (CAT) amounts and activities were monitored. Both extracts increased total protein content, while the increase of enzyme amount and activity was obtained only with A. melanantherum extract and restricted to CAT. The activity of CuZnSOD family was not affected, while SOD1 and SOD2 amounts were significantly decreased, indicating potential involvement of extracellular CuZnSOD. Obtained results strongly support the traditional use of A. flavum and A. melanantherum in nutrition and recommend them for further study.

Subacute alcohol and/or disulfiram intake affects bioelements and redox status in rat testes.

PubMed

Djuric, Ana; Begic, Aida; Gobeljic, Borko; Pantelic, Ana; Zebic, Goran; Stevanovic, Ivana; Djurdjevic, Dragan; Ninkovic, Milica; Prokic, Vera; Stanojevic, Ivan; Vojvodic, Danilo; Djukic, Mirjana

2017-07-01

The aim of the study was to investigate if alcohol and disulfiram (DSF) individually and in combination affect bioelements' and red-ox homeostasis in testes of the exposed rats. The animals were divided into groups according to the duration of treatments (21 and/or 42 days): C 21 /C 42 groups (controls); OL 21 and OL 22-42 groups (0.5 mL olive oil intake); A 1-21 groups (3 mL 20% ethanol intake); DSF 1-21 groups (178.5 mg DSF/kg/day intake); and A 21 +DSF 22-42 groups (the DSF ingestion followed previous 21 days' treatment with alcohol). The measured parameters in testes included metals: zinc (Zn), copper (Cu), iron (Fe), magnesium (Mg) and selenium (Se); as well as oxidative stress (OS) parameters: superoxide anion radical (O 2 •- ), glutathione reduced (GSH) and oxidized (GSSG), malondialdehyde (MDA), hydrogen peroxide (H 2 O 2 ) decomposition and activities of total superoxide dismutase (tSOD), glutathione-S-transferase (GST) and glutathione reductase (GR). Metal status was changed in all experimental groups (Fe rose, Zn fell, while Cu increased in A 21 +DSF 24-32 groups). Development of OS was demonstrated in A 1-21 groups, but not in DSF 1-21 groups. In A 21 +DSF 22-42 groups, OS was partially reduced compared to A groups (A 1-21 >MDA>C; A 1-21

A role for Candida albicans superoxide dismutase enzymes in glucose signaling.

PubMed

Broxton, Chynna N; He, Bixi; Bruno, Vincent M; Culotta, Valeria C

2018-01-01

The Saccharomyces cerevisiae and Candida albicans yeasts have evolved to differentially use glucose for fermentation versus respiration. S. cerevisiae is Crabtree positive, where glucose represses respiration and promotes fermentation, while the opportunistic fungal pathogen C. albicans is Crabtree negative and does not repress respiration with glucose. We have previously shown that glucose control in S. cerevisiae involves the antioxidant enzyme Cu/Zn superoxide dismutase (SOD1), where H 2 O 2 generated by SOD1 stabilizes the casein kinase YCK1 for glucose sensing. We now demonstrate that C. albicans SODs also participate in glucose regulation. C. albicans expresses two cytosolic SODs, Cu/Zn SOD1 and Mn containing SOD3, and both complemented a S. cerevisiae sod1Δ mutant in stabilizing YCK1. Moreover, in C. albicans cells, both SODs functioned to repress glucose transporter genes in response to glucose. However, the action of SODs in glucose control has diverged in the two yeasts. In S. cerevisiae, SOD1 specifically functions in the glucose sensing pathway involving YCK1 and the RGT1 repressor, but the analogous YCK/RGT1 pathway in C. albicans shows no control by SOD enzymes. Instead C. albicans SODs work in the glucose repression pathway involving the MIG1 transcriptional repressor. In C. albicans, the SODs repress glucose uptake, while in S. cerevisiae, SOD1 activates glucose uptake, in accordance with the divergent modes for glucose utilization in these two distantly related yeasts. Copyright © 2017 Elsevier Inc. All rights reserved.

Rosette iron deficiency transcript and microRNA profiling reveals links between copper and iron homeostasis in Arabidopsis thaliana

PubMed Central

Waters, Brian M.; Stein, Ricardo J.

2012-01-01

Iron (Fe) is an essential plant micronutrient, and its deficiency limits plant growth and development on alkaline soils. Under Fe deficiency, plant responses include up-regulation of genes involved in Fe uptake from the soil. However, little is known about shoot responses to Fe deficiency. Using microarrays to probe gene expression in Kas-1 and Tsu-1 ecotypes of Arabidopsis thaliana, and comparison with existing Col-0 data, revealed conserved rosette gene expression responses to Fe deficiency. Fe-regulated genes included known metal homeostasis-related genes, and a number of genes of unknown function. Several genes responded to Fe deficiency in both roots and rosettes. Fe deficiency led to up-regulation of Cu,Zn superoxide dismutase (SOD) genes CSD1 and CSD2, and down-regulation of FeSOD genes FSD1 and FSD2. Eight microRNAs were found to respond to Fe deficiency. Three of these (miR397a, miR398a, and miR398b/c) are known to regulate transcripts of Cu-containing proteins, and were down-regulated by Fe deficiency, suggesting that they could be involved in plant adaptation to Fe limitation. Indeed, Fe deficiency led to accumulation of Cu in rosettes, prior to any detectable decrease in Fe concentration. ccs1 mutants that lack functional Cu,ZnSOD proteins were prone to greater oxidative stress under Fe deficiency, indicating that increased Cu concentration under Fe limitation has an important role in oxidative stress prevention. The present results show that Cu accumulation, microRNA regulation, and associated differential expression of Fe and CuSOD genes are coordinated responses to Fe limitation. PMID:22962679

Oxidation of nitroxyl anion to nitric oxide by copper ions

PubMed Central

Nelli, Silvia; Hillen, Mark; Buyukafsar, Kansu; Martin, William

2000-01-01

This study made use of a nitric oxide-sensitive electrode to examine possible means of generating nitric oxide from nitroxyl anion (NO−) released upon the decomposition of Angeli's salt. Our results show that copper ions (from CuSO4) catalyze the rapid and efficient oxidation of nitroxyl to nitric oxide. Indeed, the concentrations of copper required to do so (0.1–100 μM) are roughly 100-times lower than those required to generate equivalent amounts of nitric oxide from S-nitroso-N-acetyl-D,L-penicillamine (SNAP). Experiments with ascorbate (1 mM), which reduces Cu2+ ions to Cu+, and with the Cu2+ chelators, EDTA and cuprizone, and the Cu+ chelator, neocuproine, each at 1 mM, suggest that the oxidation is catalyzed by copper ions in both valency states. Some compounds containing other transition metals, i.e. methaemoglobin, ferricytochrome c and Mn(III)TMPyP, were much less efficient than CuSO4 in catalyzing the formation of nitric oxide from nitroxyl, while FeSO4, FeCl3, MnCl2, and ZnSO4 were inactive. Of the copper containing enzymes examined, Cu-Zn superoxide dismutase and ceruloplasmin were weak generators of nitric oxide from nitroxyl, even at concentrations (2500 and 30 u ml−1, respectively) vastly greater than are present endogenously. Two others, ascorbate oxidase (10 u ml−1) and tyrosinase (250 u ml−1) were inactive. Our findings suggest that a copper-containing enzyme may be responsible for the rapid oxidation of nitroxyl to nitric oxide by cells, but the identity of such an enzyme remains elusive. PMID:10991931

Effects of rutin supplementation on antioxidant status and iron, copper, and zinc contents in mouse liver and brain.

PubMed

Gao, Zhonghong; Xu, Huibi; Huang, Kaixun

2002-09-01

The effect of rutin on total antioxidant status as well as on trace elements such as iron, copper, and zinc in mouse liver and brain were studied. Mice were administrated with 0.75 g/kg or 2.25 g/kg P. O. of rutin for 30 d consecutively. Following the treatment, the activity of total antioxidant status, catalase, Cu,Zn-superoxide dismutase, Mn-superoxide dismutase, zinc, copper, and iron were measured in mouse liver and brain. The results showed that rutin significantly increased the antioxidant status and Mn-superoxide dismutase activities in mouse liver, but it had no effect on these variables in the brain. Treatment with a higher concentration of rutin significantly decreased catalase activity and iron, zinc, and copper contents in mouse liver; it also resulted in a slower weight gain for the first 20 d. These results indicate that rutin taken in proper amount can effectively improve antioxidant status, whereas at an increased dosage, it may cause trace element (such as iron, zinc, and copper) deficiencies and a decrease in the activities of related metal-containing enzymes.

Structural, chemical and optical evaluation of Cu-doped ZnO nanoparticles synthesized by an aqueous solution method

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

Iribarren, A., E-mail: augusto@imre.oc.uh.cu; Hernández-Rodríguez, E.; Maqueira, L.

Highlights: • Cu-doped ZnO nanoparticles obtained by chemical synthesis. • Substitutional or interstitial Cu into ZnO lead specific structural, chemical, and optical changes. • Incorporation efficiency of Cu atoms in ZnO as a function of the Cu concentration in the precursor dissolution. - Abstract: In this work a study of ZnO and Cu-doped ZnO nanoparticles obtained by chemical synthesis in aqueous media was carried out. Structural analysis gave the dominant presence of wurtzite ZnO phase forming a solid solution Zn{sub 1−x}Cu{sub x}O. For high Cu doping CuO phase is also present. For low Cu concentration the lattice shrinks due tomore » Cu atoms substitute Zn atoms. For high Cu concentration the lattice enlarges due to predominance of interstitial Cu. From elemental analysis we determined and analyzed the incorporation efficiency of Cu atoms in Zn{sub 1−x}Cu{sub x}O as a function of the Cu concentration in the precursor dissolution. Combining structural and chemical results we described the Cu/Zn precursor concentrations r{sub w} in which the solid solution of Cu in ZnO is predominant. In the region located at r{sub w} ≈ 0.2–0.3 it is no longer valid. For Cu/Zn precursor concentration r{sub w} > 0.3 interstitial Cu dominates, and some amount of copper oxide appears. As the Cu concentration increases, the effective size of nanoparticles decreases. Photoluminescence (PL) measurements of the Cu-doped ZnO nanoparticles were carried out and analyzed.« less

Copper-zinc electrodeposition in alkaline-sorbitol medium: Electrochemical studies and structural, morphological and chemical composition characterization

NASA Astrophysics Data System (ADS)

de Almeida, M. R. H.; Barbano, E. P.; de Carvalho, M. F.; Tulio, P. C.; Carlos, I. A.

2015-04-01

The galvanostatic technique was used to analyze the electrodeposition of Cu-Zn on to AISI 1010 steel electrode from an alkaline-sorbitol bath with various proportions of the metal ions in the bath: Cu70/Zn30, Cu50/Zn50 and Cu30/Zn70. Coloration of Cu-Zn films were whitish golden, light golden, golden/gray depending on the Cu2+/Zn2+ ratios in the electrodeposition bath, deposition current density (jdep) and charge density (qdep). The highest current efficiency was ∼54.0%, at jdep -1.0 mA cm-2 and qdep 0.40 C cm-2 in the Cu70/Zn30 bath. Energy dispersive spectroscopy indicated that electrodeposits produced from the bath Cu70/Zn30 showed higher Cu content at lower jdep. Also, for same jdep the Cu content increased with qdep. Scanning electron microscopy showed that Cu-Zn electrodeposits of high quality were obtained from the Cu70/Zn30 bath, since the films were fine-grained, except the obtained at jdep -20.0 mA cm-2 and qdep 10.0 C cm-2. Also, these electrodeposits did not present cracks. X-ray analysis of the Cu-Zn electrodeposits obtained at jdep -8.0, -20.0 and -40.0 mA cm-2, in each case, with qdep 2.0 and 10.0 C cm-2, in the Cu70/Zn30 bath, suggested the occurrence of a mixture of the following phases, CuZn, CuZn5 and Cu5Zn8. Galvanostatic electrodeposits of Cu-Zn obtained from sorbitol-alkaline baths exhibited whitish golden color, with good prospects for industrial applications, especially for decorative purposes.

Active sites for CO 2 hydrogenation to methanol on Cu/ZnO catalysts

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

Kattel, Shyam; Ramírez, Pedro J.; Chen, Jingguang G.

The active sites over commercial copper/zinc oxide/aluminum oxide (Cu/ZnO/Al 2O 3) catalysts for carbon dioxide (CO 2) hydrogenation to methanol, the Zn-Cu bimetallic sites or ZnO-Cu interfacial sites, have recently been the subject of intense debate. Here, we report a direct comparison between the activity of ZnCu and ZnO/Cu model catalysts for methanol synthesis. By combining x-ray photoemission spectroscopy, density functional theory, and kinetic Monte Carlo simulations, we can identify and characterize the reactivity of each catalyst. Both experimental and theoretical results agree that ZnCu undergoes surface oxidation under the reaction conditions so that surface Zn transforms into ZnO andmore » allows ZnCu to reach the activity of ZnO/Cu with the same Zn coverage. These results highlight a synergy of Cu and ZnO at the interface that facilitates methanol synthesis via formate intermediates.« less

Active sites for CO 2 hydrogenation to methanol on Cu/ZnO catalysts

DOE PAGES

Kattel, Shyam; Ramírez, Pedro J.; Chen, Jingguang G.; ...

2017-03-23

The active sites over commercial copper/zinc oxide/aluminum oxide (Cu/ZnO/Al 2O 3) catalysts for carbon dioxide (CO 2) hydrogenation to methanol, the Zn-Cu bimetallic sites or ZnO-Cu interfacial sites, have recently been the subject of intense debate. Here, we report a direct comparison between the activity of ZnCu and ZnO/Cu model catalysts for methanol synthesis. By combining x-ray photoemission spectroscopy, density functional theory, and kinetic Monte Carlo simulations, we can identify and characterize the reactivity of each catalyst. Both experimental and theoretical results agree that ZnCu undergoes surface oxidation under the reaction conditions so that surface Zn transforms into ZnO andmore » allows ZnCu to reach the activity of ZnO/Cu with the same Zn coverage. These results highlight a synergy of Cu and ZnO at the interface that facilitates methanol synthesis via formate intermediates.« less

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

PubMed

Khattab, M M; Al-Hrasen, M N

2006-04-01

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

[Plasma levels of mediator amino acids in patients with Parkinson disease].

PubMed

Vitreshchak, T V; Poleshchuk, V V; Piradov, M A

2004-01-01

Content of neurotransmitter amino acids before and after treatment with He-Ne-laser was measured in blood of two groups of the Parkinson's disease patients distinguished by low (first group) and high (second group) activity of monoamine oxidase B and Cu/Zn-superoxide dismutase. An increase in taurine level at the early stage of the disease (first group of patients) suggests that taurine may be a marker of compensatory abilities of the organism. The violation of the glutamate/taurine balance at the later stages of the disease and its normalization following the laserotherapy accompanied improvement of neurological symptoms.

Can ebselen prevent cisplatin-induced ovarian damage?

PubMed

Soyman, Zeynep; Uzun, Hafize; Bayindir, Nihan; Esrefoglu, Mukaddes; Boran, Birtan

2018-06-01

The occurrence of ovarian damage is a major shortcoming in treating tumors with cisplatin (CP). The present study investigates the beneficial effects of ebselen-a seleno-organic compound with antioxidant and antiinflammatory properties-vis-à-vis CP-induced ovarian damage. Twenty-eight adult female rats were divided into four study groups. Group 1 received no treatment. The rats in Groups 2, 3, and 4 were intraperitoneally administered CP (2 mg/kg/day) twice per week, for 5 weeks. Those in Group 2 received 0.3 ml saline (0.9% NaCl) intraperitoneally 60 min before each CP treatment, while those in Group 3 received 0.2 ml dimethyl sulfoxide (DMSO) and 0.3 ml saline intraperitoneally 60 min before each CP treatment. The rats in Group 4 were pretreated with an intraperitoneal injection of 15 mg/kg/day ebselen 60 min before each CP treatment. Ovarian tissue malondialdehyde (MDA), total nitric oxide (NOx), glutathione (GSH), Cu/Zn-superoxide dismutase (Cu/Zn-SOD), and catalase levels, as well as histopathological damage scores (HDSs) and serum antimullerian hormone (AMH) levels, were assessed. Cu/Zn-SOD and GSH levels were significantly higher, and MDA and NOx levels significantly lower, in Group 4 than in Groups 2 and 3. Pretreatment with ebselen significantly improved serum AMH levels, relative to Groups 2 and 3. Additionally, HDS values were significantly lower in Group 4 than in Groups 2 and 3. Our results from using an experimental rat model of CP chemotherapy suggest that ebselen use may ameliorate ovarian damage by preventing oxidative injury.

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

PubMed

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

2015-06-01

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

Effects of dietary supplementation with tribasic zinc sulfate or zinc sulfate on growth performance, zinc content and expression of zinc transporters in young pigs.

PubMed

Deng, Bo; Zhou, Xihong; Wu, Jie; Long, Ciming; Yao, Yajun; Peng, Hongxing; Wan, Dan; Wu, Xin

2017-10-01

An experiment was conducted to compare the effects of zinc sulfate (ZS) and tribasic zinc sulfate (TBZ) as sources of supplemental zinc on growth performance, serum zinc (Zn) content and messenger RNA (mRNA) expression of Zn transporters (ZnT1/ZnT2/ZnT5/ZIP4/DMT1) of young growing pigs. A total of 96 Duroc × Landrace × Yorkshire pigs were randomly allotted to two treatments and were fed a basal diet supplemented with 100 mg/kg Zn from either ZS or TBZ for 28 days. Feed : gain ratio in pigs fed TBZ were lower (P < 0.05) than pigs fed ZS, and average daily weight gain tended to increase (0.05 ≤ P ≤ 0.10) in pigs fed TBZ. Compared with pigs fed ZS, pigs fed TBZ had a higher CuZn-superoxide dismutase and Zn content in serum (P < 0.05) while they had a lower Zn content in feces (P < 0.05). In addition, ZIP4 mRNA expression of zinc transporter in either duodenum or jejunum of pigs fed TBZ were higher (P < 0.05) than pigs fed ZS. These results indicate that TBZ is more effective in serum Zn accumulation and intestinal Zn absorption, and might be a potential substitute for ZS in young growing pigs. © 2017 Japanese Society of Animal Science.

Soil solution dynamics of Cu and Zn in a Cu- and Zn-polluted soil as influenced by gamma-irradiation and Cu-Zn interaction.

PubMed

Luo, Y M; Yan, W D; Christie, P

2001-01-01

A pot experiment was conducted to study soil solution dynamics of Cu and Zn in a Cu/Zn-polluted soil as influenced by gamma-irradiation and Cu-Zn interaction. A slightly acid sandy loam was amended with Cu and Zn (as nitrates) either singly or in combination (100 mg Cu and 150 mg Zn kg(-1) soil) and was then gamma-irradiated (10 kGy). Unamended and unirradiated controls were included, and spring barley (Hordeum vulgare L. cv. Forrester) was grown for 50 days. Soil solution samples obtained using soil moisture samplers immediately before transplantation and every ten days thereafter were used directly for determination of Cu, Zn, pH and absorbance at 360 nm (A360). Cu and Zn concentrations in the solution of metal-polluted soil changed with time and were affected by gamma-irradiation and metal interaction. gamma-Irradiation raised soil solution Cu substantially but generally decreased soil solution Zn. These trends were consistent with increased dissolved organic matter (A360) and solution pH after gamma-irradiation. Combined addition of Cu and Zn usually gave higher soil solution concentrations of Cu or Zn compared with single addition of Cu or Zn in gamma-irradiated and non-irradiated soils, indicating an interaction between Cu and Zn. Cu would have been organically complexed and consequently maintained a relatively high concentration in the soil solution under higher pH conditions. Zn tends to occur mainly as free ion forms in the soil solution and is therefore sensitive to changes in pH. The extent to which gamma-irradiation and metal interaction affected solubility and bioavailability of Cu and Zn was a function of time during plant growth. Studies on soil solution metal dynamics provide very useful information for understanding metal mobility and bioavailability.

Effect of graphene oxide on copper stress in Lemna minor L.: evaluating growth, biochemical responses, and nutrient uptake.

PubMed

Hu, Changwei; Liu, Lei; Li, Xiuling; Xu, Yundi; Ge, Zhigang; Zhao, Yongjun

2018-01-05

The wide application and unique properties of graphene oxide (GO) make it to interact with other pollutants and subsequently alter their behavior and toxicity. We evaluated the influences of GO at different concentrations (1 and 5mg/L) on copper (Cu) stress in duckweed (Lemna minor L.) GO below a concentration of 5mg/L showed no adverse effects on L. minor. The addition of Cu above 10μM represented a stress condition, which was evidenced by various parameters such as frond number, percent inhibition of growth rate (I r ), total chlorophyll content, dry weight, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). When L. minor was simultaneously exposed to GO and Cu, especially at a GO concentration of 5mg/L and a Cu level above 10μM, the increase of I r and decrease of chlorophyll content were inhibited, suggesting that the Cu stress was diminished in the presence of GO. The addition of Cu alone, ranging between 5 and 20μM, increased Cu, B, Mn, Fe, Co, and Zn uptake, but decreased P uptake. Our results suggest that GO can lessen Cu stress in L. minor via Cu adsorption, thereby protecting the plants from the damaging effects of high Cu concentrations. Copyright © 2017 Elsevier B.V. All rights reserved.

Corrosion and runoff rates of Cu and three Cu-alloys in marine environments with increasing chloride deposition rate.

PubMed

Odnevall Wallinder, Inger; Zhang, Xian; Goidanich, Sara; Le Bozec, Nathalie; Herting, Gunilla; Leygraf, Christofer

2014-02-15

Bare copper sheet and three commercial Cu-based alloys, Cu15Zn, Cu4Sn and Cu5Al5Zn, have been exposed to four test sites in Brest, France, with strongly varying chloride deposition rates. The corrosion rates of all four materials decrease continuously with distance from the coast, i.e. with decreasing chloride load, and in the following order: Cu4Sn>Cu sheet>Cu15Zn>Cu5Al5Zn. The patina on all materials was composed of two main layers, Cu2O as the inner layer and Cu2(OH)3Cl as the outer layer, and with a discontinuous presence of CuCl in between. Additional minor patina constituents are SnO2 (Cu4Sn), Zn5(OH)6(CO3)2 (Cu15Zn and Cu5Al5Zn) and Zn6Al2(OH)16CO3·4H2O/Zn2Al(OH)6Cl·2H2O/Zn5Cl2(OH)8·H2O and Al2O3 (Cu5Al5Zn). The observed Zn- and Zn/Al-containing corrosion products might be important factors for the lower sensitivity of Cu15Zn and Cu5Al5Zn against chloride-induced atmospheric corrosion compared with Cu sheet and Cu4Sn. Decreasing corrosion rates with exposure time were observed for all materials and chloride loads and attributed to an improved adherence with time of the outer patina to the underlying inner oxide. Flaking of the outer patina layer was mainly observed on Cu4Sn and Cu sheet and associated with the gradual transformation of CuCl to Cu2(OH)3Cl of larger volume. After three years only Cu5Al5Zn remains lustrous because of a patina compared with the other materials that appeared brownish-reddish. Significantly lower release rates of metals compared with corresponding corrosion rates were observed for all materials. Very similar release rates of copper from all four materials were observed during the fifth year of marine exposure due to an outer surface patina that with time revealed similar constituents and solubility properties. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

Facile synthesis of Cu/tetrapod-like ZnO whisker compounds with enhanced photocatalytic properties

NASA Astrophysics Data System (ADS)

Liu, Hong; Liu, Huarong; Fan, Ximei

2017-09-01

Cu/tetrapod-like ZnO whisker (T-ZnOw) compounds were successfully synthesized using N2H4 \\cdot H2O as a reducing agent by a simple reduction method without any insert gas at room temperature. The crystal phase composition and morphology of the as-prepared samples were investigated by XRD, SEM and FESEM tests. The photocatalytic property of the as-prepared samples was detected by the degradation of methyl orange (MO) aqueous solution under UV irradiation. It can be found that Cu nanoparticles (CuNPs) dispersed on the surface of T-ZnOw increased with the increasing of Cu/Zn molar ratios (Cu/Zn MRs), and an octahedral structure of CuNPs was obtained when the sample was prepared with less than and equal to 7.30% Cu/Zn MR, but tended to a spherical or nanorod structure of CuNPs densely arranged on the surface of T-ZnOw, which is prepared by Cu/Zn MRs up to 22.00%. All the compounds exhibited excellent photocatalytic activity in decomposing of MO than T-ZnOw, the photocatalytic property of the samples increased with the increasing of Cu/Zn MRs up to 7.30%, while it decreases when further increasing the Cu/Zn MRs. The Schottky barrier of the Cu/T-ZnOw compound can effectively capture photoinduced electrons from the interface and enhanced the photocatalytic property of T-ZnOw.

Effect of dietary manganese on antioxidant status and expressions of heat shock proteins and factors in tissues of laying broiler breeders under normal and high environmental temperatures.

PubMed

Zhu, Yong-Wen; Lu, Lin; Li, Wen-Xiang; Zhang, Li-Yang; Ji, Cheng; Lin, Xi; Liu, Hsiao-Ching; Odle, Jack; Luo, Xu-Gang

2016-12-01

To investigate the effect of Mn on antioxidant status and on the expressions of heat shock proteins/factors in tissues of laying broiler breeders subjected to heat challenge, we used a completely randomised design (n 6) with a factorial arrangement of 2 environmental temperatures (normal, 21±1°C, and high, 32±1°C)×3 dietary Mn treatments (a Mn-unsupplemented basal diet (CON), or a basal diet supplemented with 120 mg Mn/kg diet, either as inorganic Mn sulphate (iMn) or as organic Mn proteinate (oMn)). There were no interactions (P>0·10) between environmental temperature and dietary Mn in any of the measured indices. High temperature decreased (P<0·003) Mn content, and also tended (P=0·07) to decrease Cu Zn superoxide dismutase (CuZnSOD) activity in the liver and heart. However, an increased Mn superoxide dismutase (MnSOD) activity (P<0·05) and a slight increase in malondialdehyde level (P=0·06) were detected in breast muscle. Up-regulated (P<0·05) expressions of heat shock factor 1 (HSF1) and HSF3 mRNA and heat shock protein 70 (HSP70) mRNA and protein were found in all three tissues. Broiler breeders fed either iMn or oMn had higher tissue Mn content (P<0·0001), heart MnSOD and CuZnSOD activities (P<0·01) and breast muscle MnSOD protein levels (P<0·05), and lower (P<0·05) breast muscle HSP70 mRNA and protein levels compared with those fed CON. Broiler breeders fed oMn had higher (P<0·03) bone Mn content than those fed iMn. These results indicate that high temperature decreases Mn retention and increases HSP70, HSF1 and HSF3 expressions in the tissues of laying broiler breeders. Furthermore, dietary supplementation with Mn in either source may enhance the heart's antioxidant ability and inhibit the expression of HSP70 in breast muscle. Finally, the organic Mn appears to be more available than inorganic Mn for bone in laying broiler breeders regardless of environmental temperatures.

Weakness of whole muscles in mice deficient in Cu, Zn superoxide dismutase is not explained by defects at the level of the contractile apparatus.

PubMed

Larkin, Lisa M; Hanes, Michael C; Kayupov, Erdan; Claflin, Dennis R; Faulkner, John A; Brooks, Susan V

2013-08-01

Mice deficient in Cu,Zn superoxide dismutase (Sod1 (-/-) mice) demonstrate elevated oxidative stress associated with rapid age-related declines in muscle mass and force. The decline in mass for muscles of Sod1 (-/-) mice is explained by a loss of muscle fibers, but the mechanism underlying the weakness is not clear. We hypothesized that the reduced maximum isometric force (F o) normalized by cross-sectional area (specific F o) for whole muscles of Sod1 (-/-) compared with wild-type (WT) mice is due to decreased specific F o of individual fibers. Force generation was measured for permeabilized fibers from muscles of Sod1 (-/-) and WT mice at 8 and 20 months of age. WT mice were also studied at 28 months to determine whether any deficits observed for fibers from Sod1 (-/-) mice were similar to those observed in old WT mice. No effects of genotype were observed for F o or specific F o at either 8 or 20 months, and no age-associated decrease in specific F o was observed for fibers from Sod1 (-/-) mice, whereas specific F o for fibers of WT mice decreased by 20 % by 28 months. Oxidative stress has also been associated with decreased maximum velocity of shortening (V max), and we found a 10 % lower V max for fibers from Sod1 (-/-) compared with WT mice at 20 months. We conclude that the low specific F o of muscles of Sod1 (-/-) mice is not explained by damage to contractile proteins. Moreover, the properties of fibers of Sod1 (-/-) mice do not recapitulate those observed with aging in WT animals.

Concurrent Increases and Decreases in Local Stability and Conformational Heterogeneity in Cu, Zn Superoxide Dismutase Variants Revealed by Temperature-Dependence of Amide Chemical Shifts.

PubMed

Doyle, Colleen M; Rumfeldt, Jessica A; Broom, Helen R; Sekhar, Ashok; Kay, Lewis E; Meiering, Elizabeth M

2016-03-08

The chemical shifts of backbone amide protons in proteins are sensitive reporters of local structural stability and conformational heterogeneity, which can be determined from their readily measured linear and nonlinear temperature-dependences, respectively. Here we report analyses of amide proton temperature-dependences for native dimeric Cu, Zn superoxide dismutase (holo pWT SOD1) and structurally diverse mutant SOD1s associated with amyotrophic lateral sclerosis (ALS). Holo pWT SOD1 loses structure with temperature first at its periphery and, while having extremely high global stability, nevertheless exhibits extensive conformational heterogeneity, with ∼1 in 5 residues showing evidence for population of low energy alternative states. The holo G93A and E100G ALS mutants have moderately decreased global stability, whereas V148I is slightly stabilized. Comparison of the holo mutants as well as the marginally stable immature monomeric unmetalated and disulfide-reduced (apo(2SH)) pWT with holo pWT shows that changes in the local structural stability of individual amides vary greatly, with average changes corresponding to differences in global protein stability measured by differential scanning calorimetry. Mutants also exhibit altered conformational heterogeneity compared to pWT. Strikingly, substantial increases as well as decreases in local stability and conformational heterogeneity occur, in particular upon maturation and for G93A. Thus, the temperature-dependence of amide shifts for SOD1 variants is a rich source of information on the location and extent of perturbation of structure upon covalent changes and ligand binding. The implications for potential mechanisms of toxic misfolding of SOD1 in disease and for general aspects of protein energetics, including entropy-enthalpy compensation, are discussed.

Mitochondria-derived hydrogen peroxide selectively enhances T cell receptor-initiated signal transduction.

PubMed

Gill, Tejpal; Levine, Alan D

2013-09-06

T cell receptor (TCR)-initiated signal transduction is reported to increase production of intracellular reactive oxygen species, such as superoxide (O2˙(-)) and hydrogen peroxide (H2O2), as second messengers. Although H2O2 can modulate signal transduction by inactivating protein phosphatases, the mechanism and the subcellular localization of intracellular H2O2 as a second messenger of the TCR are not known. The antioxidant enzyme superoxide dismutase (SOD) catalyzes the dismutation of highly reactive O2˙(-) into H2O2 and thus acts as an intracellular generator of H2O2. As charged O2˙(-) is unable to diffuse through intracellular membranes, cells express distinct SOD isoforms in the cytosol (Cu,Zn-SOD) and mitochondria (Mn-SOD), where they locally scavenge O2˙(-) leading to production of H2O2. A 2-fold organelle-specific overexpression of either SOD in Jurkat T cell lines increases intracellular production of H2O2 but does not alter the levels of intracellular H2O2 scavenging enzymes such as catalase, membrane-bound peroxiredoxin1 (Prx1), and cytosolic Prx2. We report that overexpression of Mn-SOD enhances tyrosine phosphorylation of TCR-associated membrane proximal signal transduction molecules Lck, LAT, ZAP70, PLCγ1, and SLP76 within 1 min of TCR cross-linking. This increase in mitochondrial H2O2 specifically modulates MAPK signaling through the JNK/cJun pathway, whereas overexpressing Cu,Zn-SOD had no effect on any of these TCR-mediated signaling molecules. As mitochondria translocate to the immunological synapse during TCR activation, we hypothesize this translocation provides the effective concentration of H2O2 required to selectively modulate downstream signal transduction pathways.

Differential effects of eNOS uncoupling on conduit and small arteries in GTP-cyclohydrolase I-deficient hph-1 mice.

PubMed

d'Uscio, Livius V; Smith, Leslie A; Katusic, Zvonimir S

2011-12-01

In the present study, we used the hph-1 mouse, which displays GTP-cyclohydrolase I (GTPCH I) deficiency, to test the hypothesis that loss of tetrahydrobiopterin (BH(4)) in conduit and small arteries activates compensatory mechanisms designed to protect vascular wall from oxidative stress induced by uncoupling of endothelial nitric oxide synthase (eNOS). Both GTPCH I activity and BH(4) levels were reduced in the aortas and small mesenteric arteries of hph-1 mice. However, the BH(4)-to-7,8-dihydrobiopterin ratio was significantly reduced only in hph-1 aortas. Furthermore, superoxide anion and 3-nitrotyrosine production were significantly enhanced in aortas but not in small mesenteric arteries of hph-1 mice. In contrast to the aorta, protein expression of copper- and zinc-containing superoxide dismutase (CuZnSOD) was significantly increased in small mesenteric arteries of hph-1 mice. Protein expression of catalase was increased in both aortas and small mesenteric arteries of hph-1 mice. Further analysis of endothelial nitric oxide synthase (eNOS)/cyclic guanosine monophosphate (cGMP) signaling demonstrated that protein expression of phosphorylated Ser(1177)-eNOS as well as basal cGMP levels and hydrogen peroxide was increased in hph-1 aortas. Increased production of hydrogen peroxide in hph-1 mice aortas appears to be the most likely mechanism responsible for phosphorylation of eNOS and elevation of cGMP. In contrast, upregulation of CuZnSOD and catalase in resistance arteries is sufficient to protect vascular tissue from increased production of reactive oxygen species generated by uncoupling of eNOS. The results of our study suggest that anatomical origin determines the ability of vessel wall to cope with oxidative stress induced by uncoupling of eNOS.

Low pH-Induced Changes of Antioxidant Enzyme and ATPase Activities in the Roots of Rice (Oryza sativa L.) Seedlings

PubMed Central

Zhang, Yi-Kai; Zhu, De-Feng; Zhang, Yu-Ping; Chen, Hui-Zhe; Xiang, Jing; Lin, Xian-Qing

2015-01-01

Soil acidification is the main problem in the current rice production. Here, the effects of low pH on the root growth, reactive oxygen species metabolism, plasma membrane functions, and the transcript levels of the related genes were investigated in rice seedlings (Oryza sativa L.) in a hydroponic system at pH 3.5, 4.5, and 5.5. There were two hybrid rice cultivars in this trial, including Yongyou 12 (YY12, a japonica hybrid) and Zhongzheyou 1 (ZZY1, an indica hybrid). Higher H+ activity markedly decreased root length, the proportion of fine roots, and dry matter production, but induced a significant accumulation of hydrogen peroxide (H2O2), and led to serious lipid peroxidation in the roots of the two varieties. The transcript levels of copper/zinc superoxide dismutase 1 (Cu/Zn SOD1), copper/zinc superoxide dismutase 2 (Cu/Zn SOD2), catalase A (CATA) and catalase B (CATB) genes in YY12 and ZZY1 roots were significantly down-regulated after low pH exposure for two weeks. Meanwhile, a significant decrease was observed in the expression of the P-type Ca2+-ATPases in roots at pH 3.5. The activities of antioxidant enzymes (SOD, CAT) and plasma membrane (PM) Ca2+-ATPase in the two varieties were dramatically inhibited by strong rhizosphere acidification. However, the expression levels of ascorbate peroxidase 1 (APX1) and PM H+-ATPase isoform 7 were up-regulated under H+ stress compared with the control. Significantly higher activities of APX and PM H+-ATPase could contribute to the adaptation of rice roots to low pH. PMID:25719552

Cryoprotective role of organic Zn and Cu supplementation in goats (Capra hircus) diet.

PubMed

Arangasamy, Arunachalam; Krishnaiah, Mayasula Venkata; Manohar, Narasimhaiah; Selvaraju, Sellappan; Rani, Guvvala Pushpa; Soren, Nira Manik; Reddy, Ippala Janardhan; Ravindra, Janivara Parameshwaraiah

2018-04-01

The current study focused on cryopreservation and assessment of characters of post-thaw semen of indigenous Osmanabadi bucks maintained with standard diet, supplemented with different concentrations of organic zinc (Zn), copper (Cu) or in combination, for a period of 180 days. The different doses of organic Zn and Cu were fed per kg DM basis, Zn groups (low: Zn20, medium: Zn40 and high: Zn60), Cu groups: (low: Cu12.5, medium: Cu25 and high: Cu37.5) and combination of Zn + Cu groups (low: Zn20 + Cu12.5, medium: Zn40 + Cu25 and high: Zn60 + Cu37.5) respectively. The control group bucks were maintained mainly on the basal diet without any additional mineral supplementation. Two hundred and forty (240) semen samples were collected from 40 bucks aged 11 months, through electro ejaculator method, processed and analysed for sperm quality parameters both at pre freeze and post-thaw stage. The semen samples were diluted in Tris egg yolk extender, cooled and equilibrated for 4 h at 5 °C, cryopreserved using programmable freezer (PLANER Kryo 360-1.7) and stored at -196 °C. The organic trace minerals (Zn, Cu and Zn + Cu) protected the spermatozoa against the cryoinjury and maintained higher post-thaw semen parameters except in high Zn group. Additional feeding of organic Cu and Zn to bucks had a protective role and resulted in higher sperm liveability, plasma membrane and acrosome integrities, motility and velocity and reduced oxidative stress in supplemented goats (P < 0.05). Copyright © 2018 Elsevier Inc. All rights reserved.

Oxidative stress involvement in Physalis angulata-induced apoptosis in human oral cancer cells.

PubMed

Lee, H-Z; Liu, W-Z; Hsieh, W-T; Tang, F-Y; Chung, J-G; Leung, Henry W-C

2009-03-01

In this report, we investigated the role of oxidative stress in Physalis angulata-induced apoptosis of human oral cancer cells. P. angulata-induced apoptosis was characterized by nuclear morphological changes, membrane blebbing and activation of caspase-9. Exposure of HSC-3 cells to P. angulata caused production of reactive oxygen species and up-regulation of oxidative stress markers heme oxygenase-1 (HO-1), superoxide dismutase (SOD), heat shock protein 70 (HSP70) and caspase-4. Down-regulation of HO-1, SOD and HSP70 proteins expression by attenuation of oxidative stress, pretreatment with glutathione or N-acetylcysteine, significantly decreased P. angulata-triggered cell death. The present study also demonstrated that the mitochondria and the endoplasmic reticulum are the targets of P. angulata in HSC-3 cells. Our results revealed that: (1) reactive oxygen species may play a dominant role in this process, (2) P. angulata induces oxidative stress in HSC-3 cells, (3) P. angulata-initiated apoptosis is caused through oxidative stress-dependent induction of heme oxygenase-1, Cu/Zn SOD and HSP70 proteins expression and (4) antioxidants inhibited P. angulata-induced cell death through inhibition of the proteins expression of HO-1, Cu/Zn SOD and HSP70.

Increased oxidative/nitrosative stress and decreased antioxidant enzyme activities in prostate cancer.

PubMed

Arsova-Sarafinovska, Zorica; Eken, Ayse; Matevska, Nadica; Erdem, Onur; Sayal, Ahmet; Savaser, Ayhan; Banev, Saso; Petrovski, Daniel; Dzikova, Sonja; Georgiev, Vladimir; Sikole, Aleksandar; Ozgök, Yaşar; Suturkova, Ljubica; Dimovski, Aleksandar J; Aydin, Ahmet

2009-08-01

The study was aimed to evaluate the oxidative/nitrosative stress status in prostate cancer (CaP) and benign prostatic hyperplasia (BPH). 312 men from two different populations were included: 163 men from Macedonia (73 CaP patients, 67 BPH patients and 23 control subjects) and 149 men from Turkey (34 prostate cancer patients, 100 BPH patients and 15 control subjects). We measured erythrocyte malondialdehyde (MDA) levels, erythrocyte activities of superoxide dismutase (CuZn-SOD), glutathione peroxidase (GPX) and catalase (CAT); plasma nitrite/nitrate (NO(2)(-)/NO(3)(-)), cGMP and 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels. A similar pattern of alteration in the oxidative/nitrosative stress-related parameters was found in both, Macedonian and Turkish studied samples: higher MDA concentrations with lower GPX and CuZn-SOD activities in CaP patients versus controls and BPH groups. The CAT activity was decreased in the CaP patients versus controls in the Turkish studied sample. Furthermore, CaP patients had increased plasma NO(2)(-)/NO(3)(-) and cGMP levels versus controls and BPH groups in both studied samples. This study has confirmed an imbalance in the oxidative stress/antioxidant status and revealed an altered nitrosative status in prostate cancer patients.

TRX is up-regulated by fibroblast growth factor-2 in lung carcinoma.

PubMed

Deng, Zheng-Hao; Cao, Hui-Qiu; Hu, Yong-Bin; Wen, Ji-Fang; Zhou, Jian-Hua

2011-01-01

We have previously shown that exogenous fibroblast growth factor-2 (FGF-2) inhibits apoptosis of the small-cell lung cancer (SCLC) cell line NCI-H446, but the underlying mechanism remains unknown. In this study, the protein profiles of FGF-2-treated and untreated NCI-H446 cells were determined by 2-D gel electrophoresis combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and bioinformatics. Differential expression analysis of the protein profiles after FGF-2 treatment identified a total of 24 protein spots, of which nine were up-regulated and 15 were down-regulated. Four proteins were identified by MALDI-TOF-MS: thioredoxin (TRX), visfatin, ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) and Cu/Zn superoxide dismutase (CuZn-SOD). Western blotting revealed that TRX was up-regulated in NCI-H446 and A549 cells treated with FGF-2. Furthermore, immunohistochemical staining confirmed that both FGF-2 and TRX were overexpressed in lung cancer tissues and could be correlated with both lymph node metastasis and clinical stage. These data indicate that TRX may be involved in the FGF-2 signaling pathway. © 2010 The Authors. APMIS © 2010 APMIS.

Effects of a flavonoid extract from Cynomorium songaricum on the swimming endurance of rats.

PubMed

Yu, Fa-Rong; Liu, Ying; Cui, Yong-Zhi; Chan, Er-Qing; Xie, Ming-Ren; McGuire, Peter P; Yu, Fa-Hong

2010-01-01

The present study investigated the effects of a flavonoid extract from Cynomorium songaricum on the swimming endurance of rats by measuring changes of free radical scavenging enzymes, such as CuZn-SOD (copper, zinc-superoxide dismutase) and GSH-px (glutathione peroxidase), and body weights. Significant and dose-dependent antioxidant and anti-fatigue effects of flavonoids (rutin, catechin and isoquercitrin) on swimming rats were observed during 10 days of swimming exercise. After treatment with the flavonoid extract at doses of 0.5, 1.0, and 2.0 g/kg body weight, the CuZn-SOD and GSH-px activities in swimming rats were increased by 1.4%, 3.3%, 4.1% and 112.2%, 208.7%, 261.7%, respectively, while the levels of MDA (malondialdehyde) were decreased by 64.7%, 79.4%, and 86.4% respectively. Furthermore, the average body weight and the total swimming time were increased by 3.1%, 8.8%, 10.6%, and 7.7%, 34.5%, 61.5%, respectively. Our experimental results suggest that flavonoid supplementation could not only reduce free radical formation and scavenge free radicals, but also enhance endurance exercise performance by reducing muscle fatigue.

Ferulic acid prevents liver injury and increases the anti-tumor effect of diosbulbin B in vivo.

PubMed

Wang, Jun-ming; Sheng, Yu-chen; Ji, Li-li; Wang, Zheng-tao

2014-06-01

The present study is designed to investigate the protection by ferulic acid against the hepatotoxicity induced by diosbulbin B and its possible mechanism, and further observe whether ferulic acid augments diosbulbin B-induced anti-tumor activity. The results show that ferulic acid decreases diosbulbin B-increased serum alanine transaminase/aspartate transaminase (ALT/AST) levels. Ferulic acid also decreases lipid peroxide (LPO) levels which are elevated in diosbulbin B-treated mice. Histological evaluation of the liver demonstrates hydropic degeneration in diosbulbin B-treated mice, while ferulic acid reverses this injury. Moreover, the activities of copper- and zinc-containing superoxide dismutase (CuZn-SOD) and catalase (CAT) are decreased in the livers of diosbulbin B-treated mice, while ferulic acid reverses these decreases. Further results demonstrate that the mRNA expressions of CuZn-SOD and CAT in diosbulbin B-treated mouse liver are significantly decreased, while ferulic acid prevents this decrease. In addition, ferulic acid also augments diosbulbin B-induced tumor growth inhibition compared with diosbulbin B alone. Taken together, the present study shows that ferulic acid prevents diosbulbin B-induced liver injury via ameliorating diosbulbin B-induced liver oxidative stress injury and augments diosbulbin B-induced anti-tumor activity.

Antioxidant effects of a cinnamon extract in people with impaired fasting glucose that are overweight or obese.

PubMed

Roussel, Anne-Marie; Hininger, Isabelle; Benaraba, Rachida; Ziegenfuss, Tim N; Anderson, Richard A

2009-02-01

To determine the effects of a dried aqueous extract of cinnamon on antioxidant status of people with impaired fasting glucose that are overweight or obese. Twenty-two subjects, with impaired fasting blood glucose with BMI ranging from 25 to 45, were enrolled in a double-blind placebo-controlled trial. Subjects were given capsules containing either a placebo or 250 mg of an aqueous extract of cinnamon (Cinnulin PF) two times per day for 12 weeks. Plasma malondialdehyde (MDA) concentrations were assessed using high performance liquid chromatography and plasma antioxidant status was evaluated using ferric reducing antioxidant power (FRAP) assay. Erythrocyte Cu-Zn superoxide (Cu-Zn SOD) activity was measured after hemoglobin precipitation by monitoring the auto-oxidation of pyrogallol and erythrocyte glutathione peroxidase (GPx) activity by established methods. FRAP and plasma thiol (SH) groups increased, while plasma MDA levels decreased in subjects receiving the cinnamon extract. Effects were larger after 12 than 6 weeks. There was also a positive correlation (r = 0.74; p = 0.014) between MDA and plasma glucose. This study supports the hypothesis that the inclusion of water soluble cinnamon compounds in the diet could reduce risk factors associated with diabetes and cardiovascular disease.

Electrodeposition of Zn and Cu-Zn alloy from ZnO/CuO precursors in deep eutectic solvent

NASA Astrophysics Data System (ADS)

Xie, Xueliang; Zou, Xingli; Lu, Xionggang; Lu, Changyuan; Cheng, Hongwei; Xu, Qian; Zhou, Zhongfu

2016-11-01

The electrodeposition of Zn and Cu-Zn alloy has been investigated in choline chloride (ChCl)/urea (1:2 molar ratio) based deep eutectic solvent (DES). Cyclic voltammetry study demonstrates that the reduction of Zn(II) to Zn is a diffusion-controlled quasi-reversible, one-step, two electrons transfer process. Chronoamperometric investigation indicates that the electrodeposition of Zn on a Cu electrode typically involves three-dimensional instantaneous nucleation with diffusion-controlled growth process. Micro/nanostructured Zn films can be obtained by controlling the electrodeposition potential and temperature. The electrodeposited Zn crystals preferentially orient parallel to the (101) plane. The Zn films electrodeposited under more positive potentials and low temperatures exhibit improved corrosion resistance in 3 wt% NaCl solution. In addition, Cu-Zn alloy films have also been electrodeposited directly from CuO-ZnO precursors in ChCl/urea-based DES. The XRD analysis indicates that the phase composition of the electrodeposited Cu-Zn alloy depends on the electrodeposition potential.

Complete transformation of ZnO and CuO nanoparticles in culture medium and lymphocyte cells during toxicity testing.

PubMed

Ivask, Angela; Scheckel, Kirk G; Kapruwan, Pankaj; Stone, Vicki; Yin, Hong; Voelcker, Nicolas H; Lombi, Enzo

2017-03-01

Here, we present evidence on complete transformation of ZnO and CuO nanoparticles, which are among the most heavily studied metal oxide particles, during 24 h in vitro toxicological testing with human T-lymphocytes. Synchrotron radiation-based X-ray absorption near edge structure (XANES) spectroscopy results revealed that Zn speciation profiles of 30 nm and 80 nm ZnO nanoparticles, and ZnSO 4 - exposed cells were almost identical with the prevailing species being Zn-cysteine. This suggests that ZnO nanoparticles are rapidly transformed during a standard in vitro toxicological assay, and are sequestered intracellularly, analogously to soluble Zn. Complete transformation of ZnO in the test conditions was further supported by almost identical Zn spectra in medium to which ZnO nanoparticles or ZnSO 4 was added. Likewise, Cu XANES spectra for CuO and CuSO 4 -exposed cells and cell culture media were similar. These results together with our observation on similar toxicological profiles of ZnO and soluble Zn, and CuO and soluble Cu, underline the importance of dissolution and subsequent transformation of ZnO and CuO nanoparticles during toxicological testing and provide evidence that the nano-specific effect of ZnO and CuO nanoparticles is negligible in this system. We strongly suggest to account for this aspect when interpreting the toxicological results of ZnO and CuO nanoparticles.

Complete transformation of ZnO and CuO nanoparticles in ...

EPA Pesticide Factsheets

Here, we present evidence on complete transformation of ZnO and CuO nanoparticles, which are among the most heavily studied metal oxide particles, during 24 h in vitro toxicological testing with human T-lymphocytes. Synchrotron radiation-based X-ray absorption near edge structure (XANES) spectroscopy results revealed that Zn speciation profiles of 30 nm and 80 nm ZnO nanoparticles, and ZnSO4- exposed cells were almost identical with the prevailing species being Zn-cysteine. This suggests that ZnO nanoparticles are rapidly transformed during a standard in vitro toxicological assay, and are sequestered intracellularly, analogously to soluble Zn. Complete transformation of ZnO in the test conditions was further supported by almost identical Zn spectra in medium to which ZnO nanoparticles or ZnSO4 was added. Likewise, Cu XANES spectra for CuO and CuSO4-exposed cells and cell culture media were similar. These results together with our observation on similar toxicological profiles of ZnO and soluble Zn, and CuO and soluble Cu, underline the importance of dissolution and subsequent transformation of ZnO and CuO nanoparticles during toxicological testing and provide evidence that the nano-specific effect of ZnO and CuO nanoparticulates is negligible in this system. We strongly suggest to account for this aspect when interpreting the toxicological results of ZnO and CuO nanoparticles. Although a number of studies have discussed the transformation of nanoparticles during

Quantifying point defects in Cu 2 ZnSn(S,Se) 4 thin films using resonant x-ray diffraction

DOE PAGES

Stone, Kevin H.; Christensen, Steven T.; Harvey, Steven P.; ...

2016-10-17

Cu 2ZnSn(S,Se)4 is an interesting, earth abundant photovoltaic material, but has suffered from low open circuit voltage. To better understand the film structure, we have measured resonant x-ray diffraction across the Cu and Zn K-edges for the device quality thin films of Cu 2ZnSnS4 (8.6% efficiency) and Cu 2ZnSn(S,Se)4 (3.5% efficiency). This approach allows for the confirmation of the underlying kesterite structure and quantification of the concentration of point defects and vacancies on the Cu, Zn, and Sn sublattices. Rietveld refinement of powder diffraction data collected at multiple energies is used to determine that there exists a high level ofmore » Cu Zn and Zn Cu defects on the 2c and 2d Wyckoff positions. We observe a significantly lower concentration of Zn Sn defects and Cu or Zn vacancies.« less

Abundant defects and defect clusters in kesterite Cu2ZnSnS4 and Cu2ZnSnSe4

NASA Astrophysics Data System (ADS)

Chen, Shiyou; Wang, Lin-Wang; Walsh, Aron; Gong, Xin-Gao; Wei, Su-Huai

2013-03-01

Cu2ZnSnS4 and Cu2ZnSnSe4 are drawing intensive attention as the light-absorber materials in thin-film solar cells. A large variety of intrinsic defects can be formed in these quaternary semiconductors, which have important influence on their optical and electrical properties, and hence their photovoltaic performance. We will present our first-principles calculation study on a series of intrinsic defects and defect clusters in Cu2ZnSnS4 and Cu2ZnSnSe4, and discuss: (i) strong phase-competition between the kesterites and the coexisting secondary compounds; (ii) the dominant CuZn antisites and Cu vacancies which determine the intrinsic p-type conductivity, and their dependence on the elemental ratios; (iii) the high population of charge-compensated defect clusters (like VCu + ZnCu and 2CuZn + SnZn) and their contribution to non-stoichiometry ; (iv) the deep-level defects which act as recombination centers. Based on the calculation, we will explain the experimental observation that Cu poor and Zn rich conditions give the highest solar cell efficiency, as well as suggesting an efficiency limitation in Cu2ZnSn(S,Se)4 cells with high S composition. Supported by NSF of China, JCAP: a U.S. DOE Energy Innovation Hub, Royal Society of U.K. and EPSRC, and U.S. DOE.

New Production Routes for Medical Isotopes 64Cu and 67Cu Using Accelerator Neutrons

NASA Astrophysics Data System (ADS)

Kin, Tadahiro; Nagai, Yasuki; Iwamoto, Nobuyuki; Minato, Futoshi; Iwamoto, Osamu; Hatsukawa, Yuichi; Segawa, Mariko; Harada, Hideo; Konno, Chikara; Ochiai, Kentaro; Takakura, Kosuke

2013-03-01

We have measured the activation cross sections producing 64Cu and 67Cu, promising medical radioisotopes for molecular imaging and radioimmunotherapy, by bombarding a natural zinc sample with 14 MeV neutrons. We estimated the production yields of 64Cu and 67Cu by fast neutrons from \\text{natC(d,n) with 40 MeV 5 mA deuterons. We used the present result together with the evaluated cross section of Zn isotopes. The calculated 64Cu yield is 1.8 TBq (175 g 64Zn) for 12 h of irradiation; the yields of 67Cu by 67Zn(n,p)67Cu and 68Zn(n,x)67Cu were 249 GBq (184 g 67Zn) and 287 GBq (186 g 68Zn) at the end of 2 days of irradiation, respectively. From the results, we proposed a new route to produce 67Cu with very little radionuclide impurity via the 68Zn(n,x)67Cu reaction, and showed the 64Zn(n,p)64Cu reaction to be a promising route to produce 64Cu. Both 67Cu and 64Cu are noted to be produced using fast neutrons.

An Optimal Dietary Zinc Level of Brown-Egg Laying Hens Fed a Corn-Soybean Meal Diet.

PubMed

Qin, Shizhen; Lu, Lin; Zhang, Xichun; Liao, Xiudong; Zhang, Liyang; Guo, Yanli; Luo, Xugang

2017-06-01

An experiment was conducted to estimate the optimal dietary zinc (Zn) level of brown-egg laying hens fed a corn-soybean meal diet from 20 to 40 weeks of age. A total of 120 20-week-old Beijing Red commercial laying hens were randomly allotted by bodyweight to one of five treatments with six replicates of four birds each in a completely randomized design, and fed a Zn-unsupplemented corn-soybean meal basal diet containing 27.95 mg Zn/kg by analysis and the basal diets supplemented with 30, 60, 90, or 120 mg Zn/kg as Zn sulfate (reagent grade ZnSO 4 ·7H 2 O) for a duration of 20 weeks. Laying performance, egg quality, tissue Zn concentrations, and activities of serum alkaline phosphatase (AKP), and liver copper-Zn superoxide dismutase (CuZnSOD) were measured. Regression analyses were performed to estimate an optimal dietary Zn level whenever a significant quadratic response (P < 0.05) was observed. Tibia Zn concentration (P = 0.002) and serum AKP activity (P = 0.010) showed significant quadratic responses to dietary supplemental Zn levels. The estimates of dietary Zn requirements for brown-egg laying hens from 20 to 40 weeks of age were 71.95 and 64.63 mg/kg for tibia Zn concentration and serum AKP activity, respectively. The results from this study indicate that the tibia Zn might be a more suitable and reliable parameter for Zn requirement estimation, and the optimal dietary Zn level would be about 72 mg/kg for brown-egg laying hens fed a corn-soybean meal diet from 20 to 40 weeks of age.

Effects of Oridonin on growth performance and oxidative stress in broilers challenged with lipopolysaccharide.

PubMed

Zheng, X C; Wu, Q J; Song, Z H; Zhang, H; Zhang, J F; Zhang, L L; Zhang, T Y; Wang, C; Wang, T

2016-10-01

This study was conducted to investigate the effects of oridonin (ORI) on growth performance and antioxidant capacity in broiler chickens that were repeatedly challenged with lipopolysaccharide (LPS). A total of 384 one-day-old male Arbor Acre broiler chickens were randomly assigned to 8 treatments with 6 replicate cages per treatment and 8 birds per replicate. There were 4 dietary treatments: the control group (birds fed the basal diet), the ORI 50 group, the ORI 80 group, and the ORI 100 group (the basal diet supplemented with 50, 80, and 100 mg/kg oridonin, respectively). Broilers were intraperitoneally injected with either 250 μg/kg BW LPS or an equivalent amount of sterile saline at 16, 18, and 20 d of age. LPS decreased the average daily weight gain (ADG), the average daily feed intake (ADFI), and the feed conversion ratio (FCR) of broiler chickens (P < 0.05); oridonin supplementation had no effects on performance whether before or after LPS injection (P > 0.05). LPS stimulation increased the relative weight of the spleen and bursa (P < 0.05); oridonin inclusion markedly attenuated the increased spleen index (P < 0.05). Additionally, the LPS-induced increases in the concentrations of malondialdehyde (MDA) and decreases in activities of total superoxide dismutase (T-SOD), total antioxidant capacity (T-AOC) and catalase (CAT) were dramatically attenuated by oridonin in both the serum and liver (P < 0.05). Furthermore, LPS down-regulated the mRNA expressions of nuclear factor erythroid 2-related factor 2 (Nrf2), copper and zinc superoxide dismutase (Cu/Zn-SOD), manganese superoxide dismutase (Mn-SOD), glutathione peroxidase (GPx1), and CAT in the liver (P < 0.05), However, oridonin inclusion increased the liver mRNA expression levels of Nrf2, Cu/Zn-SOD, Mn-SOD, CAT, and GPx1 (P < 0.05). It was concluded that the dietary oridonin supplementation at an optimum dose of 100 mg/kg improves the antioxidant capacity in broilers, as evidenced by the decrease in MDA and the increase in total SOD activities and mRNA expression levels of the liver antioxidant genes, although the effects on growth performance was negligible. © Crown copyright 2016.

Tuning the emission of aqueous Cu:ZnSe quantum dots to yellow light window

NASA Astrophysics Data System (ADS)

Wang, Chunlei; Hu, Zhiyang; Xu, Shuhong; Wang, Yanbin; Zhao, Zengxia; Wang, Zhuyuan; Cui, Yiping

2015-07-01

Synthesis of internally doped Cu:ZnSe QDs in an aqueous solution still suffers from narrow tunable emissions from the blue to green light window. In this work, we extended the emission window of aqueous Cu:ZnSe QDs to the yellow light window. Our results show that high solution pH, multiple injections of Zn precursors, and nucleation doping strategy are three key factors for preparing yellow emitted Cu:ZnSe QDs. All these factors can depress the reactivity of CuSe nuclei and Zn monomers, promoting ZnSe growth outside CuSe nuclei rather than form ZnSe nuclei separately. With increased ZnSe QD size, the conduction band and nearby trap state energy levels shift to higher energy sites, causing Cu:ZnSe QDs to have a much longer emission.

Stable Cu and Zn isotope ratios as tracers of sources and transport of Cu and Zn in contaminated soil

NASA Astrophysics Data System (ADS)

Bigalke, Moritz; Weyer, Stefan; Kobza, Jozef; Wilcke, Wolfgang

2010-12-01

Copper and Zn metals are produced in large quantities for different applications. During Cu production, large amounts of Cu and Zn can be released to the environment. Therefore, the surroundings of Cu smelters are frequently metal-polluted. We determined Cu and Zn concentrations and Cu and Zn stable isotope ratios (δ 65Cu, δ 66Zn) in three soils at distances of 1.1, 3.8, and 5.3 km from a Slovak Cu smelter and in smelter wastes (slag, sludge, ash) to trace sources and transport of Cu and Zn in soils. Stable isotope ratios were measured by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) in total digests. Soils were heavily contaminated with concentrations up to 8087 μg g -1 Cu and 2084 μg g -1 Zn in the organic horizons. The δ 65Cu values varied little (-0.12‰ to 0.36‰) in soils and most wastes and therefore no source identification was possible. In soils, Cu became isotopically lighter with increasing depth down to 0.4 m, likely because of equilibrium reactions between dissolved and adsorbed Cu species during transport of smelter-derived Cu through the soil. The δ 66Zn IRMM values were isotopically lighter in ash (-0.41‰) and organic horizons (-0.85‰ to -0.47‰) than in bedrock (-0.28‰) and slag (0.18‰) likely mainly because of kinetic fractionation during evaporation and thus allowed for separation of smelter-Zn from native Zn in soil. In particular in the organic horizons large variations in δ 66Zn values occur, probably caused by biogeochemical fractionation in the soil-plant system. In the mineral horizons, Zn isotopes showed only minor shifts to heavier δ 66Zn values with depth mainly because of the mixing of smelter-derived Zn and native Zn in the soils. In contrast to Cu, Zn isotope fractionation between dissolved and adsorbed species was probably only a minor driver in producing the observed variations in δ 66Zn values. Our results demonstrate that metal stable isotope ratios may serve as tracer of sources, vertical dislocation, and biogeochemical behavior in contaminated soil.

Inorganic, organic, and encapsulated minerals in vegetable meal based diets for Sparus aurata (Linnaeus, 1758)

PubMed Central

Rimoldi, Simona; Robaina, Lidia E.; Torrecillas, Silvia; Terova, Genciana; Zamorano, María J.; Karalazos, Vasileios; Hamre, Kristin; Izquierdo, Marisol

2017-01-01

Substituting fishmeal (FM) with vegetable meal (VM) can markedly affect the mineral composition of feeds, and may require additional mineral supplementation. Their bioavailability and optimal supplementation levels depend also on the form of delivery of minerals. The aim of the study was to determine the effect of different delivery forms of three major trace elements (Zn, Mn and Se) in a marine teleost. Gilthead sea bream juveniles of 22.5 g were fed a VM-based diet for 12 weeks that was either not supplemented with these minerals or supplemented with inorganic, organic, or encapsulated inorganic forms of minerals in triplicate and compared to a FM-based diet. Our results showed that mineral delivery form significantly affected the biochemical composition and morphology of posterior vertebrae. Supplementation of VM-based diets with inorganic forms of the target minerals significantly promoted growth, increased the vertebral weight and content of ash and Zn, enhanced bone mineralization and affected the vertebral shape. Conversely, encapsulation of inorganic minerals reduced fish growth and vertebral mineral content, whereas supplementation of organic minerals, enhanced bone osteogenesis by upregulating bone morphogenetic protein 2 (bmp2) gene and produced vertebrae with a larger length in relation to height. Furthermore, organic mineral forms of delivery downregulated the expression of oxidative stress related genes, such as Cu/Zn superoxide dismutase (Cu/Zn sod) and glutathione peroxidase 1 (gpx-1), suggesting thus that dietary minerals supplemented in the organic form could be reasonably considered more effective than the inorganic and encapsulated forms of supply. PMID:29093992

Electrochemical corrosion behavior, microstructure and magnetic properties of sintered Nd-Fe-B permanent magnet doped by CuZn5 powders

NASA Astrophysics Data System (ADS)

Liu, W. Q.; Wang, Z.; Sun, C.; Yue, M.; Liu, Y. Q.; Zhang, D. T.; Zhang, J. X.

2014-05-01

Nd-Fe-B permanent magnets with a small amount of CuZn5 powders doping were prepared by conventional sintered method. The effects of CuZn5 contents on magnetic properties and microstructure, electrochemical corrosion resistance of sintered Nd-Fe-B magnets were systematically studied. The results show that the magnetic properties of magnets do not have a significant variation by CuZn5 powders doping; the coercivity of magnets rises gradually, while the remanence of the magnets decreases a little with increasing of the CuZn5 amount. The CuZn5 doped magnets have more positive corrosion potential, Ecorr, and much lower corrosion current density, icorr, than the magnets without CuZn5 doping, indicating CuZn5 doping could improve the corrosion resistance. Both Zn and Cu enrich mainly into the Nd-rich phase, fully improve the wettability between the Nd-rich phase and the Nd2Fe14B phase, and repair the defects of the main phase, so the coercivity of magnets doped with CuZn5 powders rises. Such microstructure modification effectively restrains the aggressive inter-granular corrosion. As a result, the CuZn5 doped magnet possesses excellent corrosion resistance in NaCl electrolyte.

Strain-dependent effects of long-term treatment with melatonin on kainic acid-induced status epilepticus, oxidative stress and the expression of heat shock proteins.

PubMed

Atanasova, Milena; Petkova, Zlatina; Pechlivanova, Daniela; Dragomirova, Petya; Blazhev, Alexander; Tchekalarova, Jana

2013-10-01

Oxidative stress is implicated in the pathogenesis of both hypertension and epileptogenesis, therefore it could be used as a tool for studying co-morbidity of hypertension and epilepsy. Clinical data suggest that melatonin is a potent antioxidant that is effective in the adjunctive therapy of hypertension and neurodegenerative diseases. The present study aimed to explore and compare the efficacy of chronic pretreatment with melatonin infused via subcutaneous osmotic mini-pumps for 14 days (10 mg/kg per day) on kainic acid (KA)-induced status epilepticus, oxidative stress and expression of heat shock protein (HSP) 72 in spontaneously hypertensive rats (SHRs) and normotensive Wistar rats. SHRs showed higher lipid peroxidation (LP) in the frontal cortex and hippocampus and decreased cytosolic superoxide dismutase (SOD/CuZn) production in the frontal cortex compared to Wistar rats. Status epilepticus (SE) induced by KA (12 mg/kg, i.p.) was accompanied by increased LP and expression of HSP 72 in the hippocampus of the two strains and increased SOD/CuZn production in the frontal cortex of SHRs. Melatonin failed to suppress seizure incidence and intensity though the latency for seizure onset was significantly increased in SHRs. Melatonin attenuated the KA-induced increase in the level of LP in the hippocampus both in SHRs and Wistar rats. However, an increased activity in SOD/CuZn and mitochondrial SOD Mn as well as reduced expression of HSP 72 in the hippocampus was observed only in Wistar rats pretreated with melatonin. Taken together, the observed strain differences in the efficacy of chronic melatonin exposure before SE suggest a lack of a direct link between the seizure activity and the markers of oxidative stress and neurotoxicity. © 2013.

Evaluation of the antioxidant effects of melatonin on the larynx mucosa of rats exposed to environmental tobacco smoke.

PubMed

Donmez, Z; Yigit, Ö; Bilici, S; Dursun, N; Gul, M; Dastan, S D; Uzun, H

2016-06-01

This study's aim was to investigate the effect of melatonin in terms of mitigating the effects of smoking on the laryngeal mucosa of rats exposed to environmental tobacco smoke. Rats were divided into four groups: Melatonin + Smoking group exposed to smoke with melatonin; Smoking group exposed to smoke without melatonin; Saline group not exposed to smoke without melatonin; Melatonin group not exposed to smoke with melatonin. CuZn-superoxide dismutase (CuZn-SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities were evaluated in plasma and tissues. Tissues were also examined the changes of squamous hyperplasia, keratosis, parakeratosis and epithelial hyperplasia by light microscope and the ultrastructural changes by electron microscope. Tissue SOD, CAT and GSH-Px activities were significantly higher in Saline and Melatonin groups than Melatonin + Smoking and Smoking groups. Plasma CuZn-SOD and CAT activities were significantly higher in Saline and Melatonin groups than Smoking group. Plasma GSH-Px showed no significant difference. The rate of epithelial hyperplasia was significantly higher in Smoking group than the other groups. The rate of parakeratosis was significantly higher in Smoking group than the other groups. The epithelial cells in Melatonin + Smoking group displayed, normal cell structure similar to those in Saline group under electron microscope. The study shows that smoking induces substantial pathological changes in the laryngeal mucosa and melatonin may have some beneficial effects in partially reversing smoking-induced laryngeal injury by inducing the expression of antioxidants; biochemical and histological outcomes also support these findings due to preventing tissue damage in laryngeal mucosa exposed to smoke. © 2015 John Wiley & Sons Ltd.

Imaging of glial cell morphology, SOD1 distribution and elemental composition in the brainstem and hippocampus of the ALS hSOD1G93A rat.

PubMed

Stamenković, Stefan; Dučić, Tanja; Stamenković, Vera; Kranz, Alexander; Andjus, Pavle R

2017-08-15

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder affecting motor and cognitive domains of the CNS. Mutations in the Cu,Zn-superoxide dismutase (SOD1) cause 20% of familial ALS and provoke formation of intracellular aggregates and copper and zinc unbinding, leading to glial activation and neurodegeneration. Therefore, we investigated glial cell morphology, intracellular SOD1 distribution, and elemental composition in the brainstem and hippocampus of the hSOD1 G93A transgenic rat model of ALS. Immunostaining for astrocytes, microglia and SOD1 revealed glial proliferation and progressive tissue accumulation of SOD1 in both brain regions of ALS rats starting already at the presymptomatic stage. Glial cell morphology analysis in the brainstem of ALS rats revealed astrocyte activation occurring before disease symptoms onset, followed by activation of microglia. Hippocampal ALS astrocytes exhibited an identical reactive profile, while microglial morphology was unchanged. Additionally, ALS brainstem astrocytes demonstrated progressive SOD1 accumulation in the cell body and processes, while microglial SOD1 levels were reduced and its distribution limited to distal cell processes. In the hippocampus both glial cell types exhibited SOD1 accumulation in the cell body. X-ray fluorescence imaging revealed decreased P and increased Ca, Cl, K, Ni, Cu and Zn in the brainstem, and higher levels of Cl, Ni and Cu, but lower levels of Zn in the hippocampus of symptomatic ALS rats. These results bring new insights into the glial response during disease development and progression in motor as well as in non-motor CNS structures, and indicate disturbed tissue elemental homeostasis as a prominent hallmark of disease pathology. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

Apolipoprotein E Genotype-Dependent Paradoxical Short-Term Effects of {sup 56}Fe Irradiation on the Brain

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

Haley, Gwendolen E.; Division of Neuroscience, Oregon National Primate Research Center, Beaverton, OR; Villasana, Laura

2012-11-01

Purpose: In humans, apolipoprotein E (apoE) is encoded by three major alleles ({epsilon}2, {epsilon}3, and {epsilon}4) and, compared to apoE3, apoE4 increases the risk of developing Alzheimer disease and cognitive impairments following various environmental challenges. Exposure to irradiation, including that of {sup 56}Fe, during space missions poses a significant risk to the central nervous system, and apoE isoform might modulate this risk. Methods and Materials: We investigated whether apoE isoform modulates hippocampus-dependent cognitive performance starting 2 weeks after {sup 56}Fe irradiation. Changes in reactive oxygen species (ROS) can affect cognition and are induced by irradiation. Therefore, after cognitive testing, wemore » assessed hippocampal ROS levels in ex vivo brain slices, using the ROS-sensitive fluorescent probe, dihydroethidium (DHE). Brain levels of 3-nitrotyrosine (3-NT), CuZn superoxide dismutase (CuZnSOD), extracellular SOD, and apoE were assessed using Western blotting analysis. Results: In the water maze, spatial memory retention was impaired by irradiation in apoE2 and apoE4 mice but enhanced by irradiation in apoE3 mice. Irradiation reduced DHE-oxidation levels in the enclosed blade of the dentate gyrus and levels of 3-NT and CuZnSOD in apoE2 but not apoE3 or apoE4 mice. Finally, irradiation increased apoE levels in apoE3 but not apoE2 or apoE4 mice. Conclusions: The short-term effects of {sup 56}Fe irradiation on hippocampal ROS levels and hippocampus-dependent spatial memory retention are apoE isoform-dependent.« less

Detection of Cu2Zn5SnSe8 and Cu2Zn6SnSe9 phases in co-evaporated Cu2ZnSnSe4 thin-films

NASA Astrophysics Data System (ADS)

Schwarz, Torsten; Marques, Miguel A. L.; Botti, Silvana; Mousel, Marina; Redinger, Alex; Siebentritt, Susanne; Cojocaru-Mirédin, Oana; Raabe, Dierk; Choi, Pyuck-Pa

2015-10-01

Cu2ZnSnSe4 thin-films for photovoltaic applications are investigated using combined atom probe tomography and ab initio density functional theory. The atom probe studies reveal nano-sized grains of Cu2Zn5SnSe8 and Cu2Zn6SnSe9 composition, which cannot be assigned to any known phase reported in the literature. Both phases are considered to be metastable, as density functional theory calculations yield positive energy differences with respect to the decomposition into Cu2ZnSnSe4 and ZnSe. Among the conceivable crystal structures for both phases, a distorted zinc-blende structure shows the lowest energy, which is a few tens of meV below the energy of a wurtzite structure. A band gap of 1.1 eV is calculated for both the Cu2Zn5SnSe8 and Cu2Zn6SnSe9 phases. Possible effects of these phases on solar cell performance are discussed.

Effects of dietary zinc oxide nanoparticles on growth performance and antioxidative status in broilers.

PubMed

Zhao, Cui-Yan; Tan, Shu-Xian; Xiao, Xi-Yu; Qiu, Xian-Shuai; Pan, Jia-Qiang; Tang, Zhao-Xin

2014-09-01

Broilers in four groups were fed a basal diet supplemented with 60 mg/kg zinc oxide (60-ZnO; control), or 20, 60, or 100 mg/kg ZnO nanoparticles (20-, 60-, and 100-nano-ZnO, respectively). Compared with the controls, after 14 days, birds in the 20- and 60-nano-ZnO groups had significantly greater weight gains and better feed conversion ratios. However, the body weight of birds in the 100-nano-ZnO group was dramatically reduced after 28 days. Relative to the control group, the total antioxidant capability (T-AOC) in serum and liver tissue was significantly higher in the 20-nano-ZnO group at all time points and also significantly higher in the 60- and 100-nano-ZnO groups in serum on days 28 and 35 and in liver tissues on days 21 and 28. Compared with the controls, the activity of copper-zinc superoxide dismutase (Cu-Zn-SOD) was significantly greater in the 60- and 100-nano-ZnO groups in serum on days 28 and 35 and in liver tissues after 21 days. Catalase activity in serum samples was significantly higher in the 20- and 60-nano-ZnO groups relative to the control and 100-nano-ZnO birds, but catalase activity in liver tissue was not affected by different nano-ZnO levels. Malondialdehyde content in serum and liver tissues was significantly reduced in the 20-, 60-, and 100-nano-ZnO groups compared with that in the control group at all time points except day 42. Taken together, our data indicate that appropriate concentration of dietary ZnO nanoparticles improves growth performance and antioxidative capabilities in broilers, and 20 mg/kg nano-ZnO is the optimal concentration.

Interfacial Phenomena in Al/Al, Al/Cu, and Cu/Cu Joints Soldered Using an Al-Zn Alloy with Ag or Cu Additions

NASA Astrophysics Data System (ADS)

Pstruś, Janusz; Gancarz, Tomasz

2014-05-01

The studies of soldered joints were carried out in systems: Al/solder/Al, Al/solder/Cu, Cu/solder/Cu, where the solder was (Al-Zn)EUT, (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Ag and (Al-Zn)EUT with 0.5, 1.0, and 1.5 at.% of Cu addition. Brazing was performed at 500 °C for 3 min. The EDS analysis indicated that the composition of the layers starting from the Cu pad was CuZn, Cu5Zn8, and CuZn4, respectively. Wetting tests were performed at 500 °C for 3, 8, 15, and 30 min, respectively. Thickness of the layers and their kinetics of growth were measured based on the SEM micrographs. The formation of interlayers was not observed from the side of Al pads. On the contrary, dissolution of the Al substrate and migration of Al-rich particles into the bulk of the solder were observed.

Cs promoted oxidation of Zn and CuZn surfaces: a combined experimental and theoretical study

NASA Astrophysics Data System (ADS)

Chaturvedi, Sanjay; Rodriguez, JoséA.; Hrbek, Jan

1997-07-01

The interaction of O 2 with Zn, {Cs}/{Zn} and {Cs}/{CuZn} surfaces was investigated using photoemission and ab initio self-consistent-field (SCF) calculations. On zinc films, the sticking probability of O 2 is extremely low (10 -3-10 -2), and O 2 exposures in the range of 10 3 to 10 4 langmuirs are necessary to produce a significant adsorption of oxygen and the transformation of metallic zinc into zinc oxide. The presence of sub monolayer coverages of cesium enhances the oxidation rate of zinc by 2-3 orders of magnitude. In the {Cs}/{Zn} system, the alkali atom donates electrons to zinc. This charge transfer facilitates the formation of Zn→O 2 dative bonds and breaking of the OO bond. For the coadsorption of Cs and O 2 on Zn(001), the larger the electron transfer from Zn into the O 2 (1 πg) orbitals, the bigger the adsorption energy of the molecule and the elongation of the OO bond. In general, cesium does not promote the oxidation of copper. In the {Cs}/{CuZn} system, copper withdraws electrons from zinc. The presence of copper in the {Cs}/{CuZn} system inhibits the oxidation of the Zn component compared with the {Cs}/{Zn} system by lowering the electron density on the Zn atoms. After exposing the {Cs}/{CuZn} system to O 2, zinc is oxidized at a rate that is larger than that found for clean CuZn surfaces and smaller than seen in {Cs}/{Zn} surfaces. Molecular hydrogen is found to have no effect on oxidized Cu, Zn and CuZn films. However, atomic hydrogen reduces ZnO to metallic zinc and CuO to Cu 2O. In the oxidized CuZn alloy, CuO is reduced first followed by the reduction of ZnO. A comparison of the behavior of O 2/Cs/Zn and H 2O/Cs/Zn systems shows that while O 2 causes severe oxidation of Cs promoted Zn surfaces, H 2O has little or no effect.

Compositional ratio effect on the surface characteristics of CuZn thin films

NASA Astrophysics Data System (ADS)

Choi, Ahrom; Park, Juyun; Kang, Yujin; Lee, Seokhee; Kang, Yong-Cheol

2018-05-01

CuZn thin films were fabricated by RF co-sputtering method on p-type Si(100) wafer with various RF powers applied on metallic Cu and Zn targets. This paper aimed to determine the morphological, chemical, and electrical properties of the deposited CuZn thin films by utilizing a surface profiler, atomic force microscopy (AFM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), UV photoelectron spectroscopy (UPS), and a 4-point probe. The thickness of the thin films was fixed at 200 ± 8 nm and the roughness of the thin films containing Cu was smaller than pure Zn thin films. XRD studies confirmed that the preferred phase changed, and this tendency is dependent on the ratio of Cu to Zn. AES spectra indicate that the obtained thin films consisted of Cu and Zn. The high resolution XPS spectra indicate that as the content of Cu increased, the intensities of Zn2+ decreased. The work function of CuZn thin films increased from 4.87 to 5.36 eV. The conductivity of CuZn alloy thin films was higher than pure metallic thin films.

Hetero-metal cation control of CuO nanostructures and their high catalytic performance for CO oxidation

NASA Astrophysics Data System (ADS)

Huang, Hongwen; Zhang, Liqiang; Wu, Kewei; Yu, Qing; Chen, Ru; Yang, Hangsheng; Peng, Xinsheng; Ye, Zhizhen

2012-11-01

A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous CuO quasi-monocrystalline nanosheets prepared at 25 °C with a thickness of ca. 10 nm and large specific surface area of 80.32 m2 g-1 is investigated intensively. These CuO nanosheets demonstrate a superior catalytic activity for CO oxidation, with features of high CO conversion efficiency (47.77 mmolCO g-1CuO h-1 at 200 °C), which is close to that reported for previously investigated supported-CuO catalysts, and a low apparent activation energy Ea (53.3 kJ mol-1).A controllable synthesis of various morphologies of CuO nanostructures with tuning by hetero-metal cations has been developed in aqueous solution at room temperature. The morphologies of CuO can be engineered from nanosheets to nanoparticles with different length ratios of the long axis to the short axis. The formation of many metal-ion complexes plays an important role in slowing the release rate of OH- and affects the reaction kinetics further. We found that the effect of hetero-metal cations on the final morphology of the CuO nanostructures was the same as that of the cooling temperature. A series of temperature-controlled experiments demonstrated this. Furthermore, among all the synthesized CuO nanostructures, the fascinating colloidal mesoporous CuO quasi-monocrystalline nanosheets prepared at 25 °C with a thickness of ca. 10 nm and large specific surface area of 80.32 m2 g-1 is investigated intensively. These CuO nanosheets demonstrate a superior catalytic activity for CO oxidation, with features of high CO conversion efficiency (47.77 mmolCO g-1CuO h-1 at 200 °C), which is close to that reported for previously investigated supported-CuO catalysts, and a low apparent activation energy Ea (53.3 kJ mol-1). Electronic supplementary information (ESI) available: Raman spectrum of Zn2Cu2 prepared at 25 °C (Fig. S1); content ratios of Zn/Cu for Zn2Cu2, Zn4Cu2 and Zn6Cu2 samples prepared at 25 °C measured by ICP-MS (Table S1); representative TEM images of Cu2, Zn2Cu2, Zn4Cu2 and Zn6Cu2 samples prepared at 25 °C (Fig. S2); size distributions along two perpendicular directions for Cu2, Zn2Cu2, Zn4Cu2 and Zn6Cu2 samples prepared at 25 °C (Fig. S3); the characteristic parameters of Cu2, Zn2Cu2, Zn4Cu2 and Zn6Cu2 samples prepared at 25 °C (Table S2); the characteristic parameters of Cu2, Zn2Cu2, Zn4Cu2 and Zn6Cu2 samples prepared at 35 °C (Table S3); SEM images of Zn2Cu2 products prepared at 20 °C, 25 °C, 30 °C and 50 °C (Fig. S4); the characteristic parameters of Zn2Cu2 prepared at 20 °C, 25 °C, 30 °C and 50 °C (Table S4); pH values of Cu2, Zn2Cu2, Zn4Cu2 and Zn6Cu2 solution without adding 1.6 mmol AE aqueous solution at 25 °C (Table S5); SEM images of Ag2Cu2, Mg2Cu2, Al2Cu2 prepared at 25 °C and EDS spectrum of Al2Cu2 (Fig. S5); the characteristic parameters of Cu2, Zn2Cu2, Ag2Cu2, Mg2Cu2 and Al2Cu2 samples prepared at 25 °C (Table S6); UV-Vis spectrum of Cu2 nanosheets prepared at 25 °C (Fig. S6); photograph of the Tyndall effect for the Cu2 solution prepared at 25 °C and UV-Vis absorption changes of Evans blue solutions after filtering the 80 ml Cu2 solution products (Fig. S7); FTIR spectrum of Cu2 nanosheets prepared at 25 °C (Fig. S8); Cu2p XPS spectrum of Cu2 nanosheets prepared at 25 °C (Fig. S9); detailed reaction rates of catalytic CO oxidation at different temperatures (Table S7); XRD pattern and SEM image of Cu2 sample after 6 hours of catalytic reaction (Fig. S10); nitrogen adsorption-desorption isotherms at 77 K of Zn4Cu2 prepared at 25 °C (Fig. S11). See DOI: 10.1039/c2nr32729e

Dietary Manganese Modulates PCB126 Toxicity, Metal Status, and MnSOD in the Rat

PubMed Central

Wang, Bingxuan; Klaren, William D.; Wels, Brian R.; Simmons, Donald L.; Olivier, Alicia K.; Wang, Kai; Robertson, Larry W.; Ludewig, Gabriele

2016-01-01

PCB126 (3,3′,4,4′,5-pentachlorobiphenyl) is a potent aryl hydrocarbon receptor agonist and induces oxidative stress. Because liver manganese (Mn) levels decrease in response to PCB126, a Mn dietary study was designed to investigate the role of Mn in PCB126 toxicity. Male Sprague Dawley rats received diets containing 0, 10, or 150 ppm added Mn for 3 weeks, followed by a single ip injection of corn oil or PCB126 (5 µmol/kg body weight). After 2 weeks, Mn, Cu, Zn, and Fe levels in the heart, liver, and liver mitochondria, and Mn-containing superoxide dismutase (MnSOD) and metallothionein mRNA, MnSOD protein, and MnSOD activity were determined. Mn levels in liver, heart, and liver mitochondria were strongly decreased by the Mn-deficient diet. Small effects on Fe levels and a stepwise increase in MnSOD activity with dietary Mn were also visible. PCB126 caused profound changes in Cu (up), Zn, Fe, and Mn (down) in liver, but not in heart, and differing effects (Cu, Zn, and Fe up, Mn down) in liver mitochondria. Liver MnSOD and metallothionein mRNA levels and MnSOD protein were increased but MnSOD activity was decreased by PCB126. PCB126-induced liver enlargement was dose-dependently reduced with increasing dietary Mn. These changes in metals homeostasis and MnSOD activity in liver but not heart may be a/the mechanism of PCB126 liver-specific toxicity. Specifically, transport of Fenton metals (Cu, Fe) into and Mn out of the mitochondria, a probable mechanism for lower MnSOD activity, may be a/the cause of PCB126-induced oxidative stress. The role of metallothioneins needs further evaluation. Dietary Mn slightly alleviated PCB126-induced toxicities. PMID:26660635

Optimization of Cu-Zn Massive Sulphide Flotation by Selective Reagents

NASA Astrophysics Data System (ADS)

Soltani, F.; Koleini, S. M. J.; Abdollahy, M.

2014-10-01

Selective floatation of base metal sulphide minerals can be achieved by using selective reagents. Sequential floatation of chalcopyrite-sphalerite from Taknar (Iran) massive sulphide ore with 3.5 % Zn and 1.26 % Cu was studied. D-optimal design of response surface methodology was used. Four mixed collector types (Aer238 + SIPX, Aero3477 + SIPX, TC1000 + SIPX and X231 + SIPX), two depressant systems (CuCN-ZnSO4 and dextrin-ZnSO4), pH and ZnSO4 dosage were considered as operational factors in the first stage of flotation. Different conditions of pH, CuSO4 dosage and SIPX dosage were studied for sphalerite flotation from first stage tailings. Aero238 + SIPX induced better selectivity for chalcopyrite against pyrite and sphalerite. Dextrin-ZnSO4 was as effective as CuCN-ZnSO4 in sphalerite-pyrite depression. Under optimum conditions, Cu recovery, Zn recovery and pyrite content in Cu concentrate were 88.99, 33.49 and 1.34 % by using Aero238 + SIPX as mixed collector, CuCN-ZnSO4 as depressant system, at ZnSO4 dosage of 200 g/t and pH 10.54. When CuCN was used at the first stage, CuSO4 consumption increased and Zn recovery decreased during the second stage. Maximum Zn recovery was 72.19 % by using 343.66 g/t of CuSO4, 22.22 g/t of SIPX and pH 9.99 at the second stage.

Synthesis of ZnO/CuO and TiO{sub 2}/CuO nanocomposites for light and ultrasound assisted degradation of a textile dye in aqueous solution

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

Muzakki, Afifah; Shabrany, Hesni; Saleh, Rosari, E-mail: rosari.saleh@gmail.com, E-mail: rosari.saleh@ui.ac.id

2016-04-19

ZnO/CuO and TiO2/CuO nanocomposites with different Zn/Cu and Ti/Cu ratios were prepared using sol-gel method. The obtained composite samples were used as catalyst. Methylene blue was used as a model of textile dye to evaluate their photocatalytic, sonocatalytic and photosonocatalytic activities. X-ray diffraction and energy dispersive X- ray analysis confirmed that only monoclinic CuO and hexagonal wurtzite ZnO structures are present in ZnO/CuO nanocomposites, while in TiO2/CuO nanocomposites monoclinic CuO and anatase TiO2 structures were observed. The degradation of methylene blue indicated that the incorporation of CuO in ZnO/CuO and TiO2/CuO nanocomposites exhibited an appreciable higher photocatalytic activity, which wasmore » mainly attributed to the extended photoresponding range and more light energy could be utilized than pure ZnO and TiO2.« less

Cu,Zn-superoxide dismutase is lower and copper chaperone CCS is higher in erythrocytes of copper-deficient rats and mice.

PubMed

West, Elizabeth C; Prohaska, Joseph R

2004-09-01

Discovery of a sensitive blood biochemical marker of copper status would be valuable for assessing marginal copper intakes. Rodent models were used to investigate whether erythrocyte concentrations of copper,zinc-superoxide dismutase (SOD), and the copper metallochaperone for SOD (CCS) were sensitive to dietary copper changes. Several models of copper deficiency were studied in postweanling male Holtzman rats, male Swiss Webster mice offspring, and both rat and mouse dams. Treatment resulted in variable but significantly altered copper status as evaluated by the presence of anemia, and lower liver copper and higher liver iron concentrations in copper-deficient compared with copper-adequate animals. Associated with this copper deficiency were consistent reductions in immunoreactive SOD and robust enhancements in CCS. In most cases, the ratio of CCS:SOD was several-fold higher in red blood cell extracts from copper-deficient compared with copper-adequate rodents. Determination of red cell CCS:SOD may be useful for assessing copper status of humans.

Rosmarinic acid and antioxidant enzyme activities in Lavandula vera MM cell suspension culture: a comparative study.

PubMed

Georgiev, Milen; Abrashev, Radoslav; Krumova, Ekaterina; Demirevska, Klimentina; Ilieva, Mladenka; Angelova, Maria

2009-11-01

The growth and intracellular protein content of lavender (Lavandula vera MM) cell suspension culture was followed along with some antioxidant defense system members-non-enzymatic (rosmarinic acid) and enzymatic [superoxide dismutase (EC 1.15.1.1) and catalase (EC 1.11.1.6)]. It was found that the media content and the cultivation mode strongly influenced the production of plant defense compounds as well as the ratio between non-enzymatic and enzymatic ones. The bioreactor culture contains about two times more rosmarinic acid, superoxide dismutase, and catalase compared to the shake-flask cultivation. These findings are discussed with respect to the relative stress levels and plant antioxidant orchestra system. It was concluded that investigated defense system components (enzymatic and non-enzymatic) were closely associated in a complex balance. The three isoenzyme forms of SOD (Cu/ZnSOD, FeSOD, and MnSOD) in the cells of Lavandula vera were revealed by polyacrylamide gel electrophoresis analysis, and the FeSOD isoform exhibited highest activity.

Survey of Nuclear Activations for Intense Proton and Deuteron Beams

DTIC Science & Technology

1992-12-24

1.115 64Zn(d,t)6𔃽 Zn -5.60 ÷ 38 min 2.34 0.51 64Zn(d,a)’ 2 Cu 7.52 ÷ 9.8 min 2.93 0.51 6’Zn(d,2p) 64Cu -2.01 - 12.8 hr 0.575 - c,o+ 12.8 hr 0.656...and for the activation of 5aCo by deuterons on a natural nickel target. 43 THICK-TARGET YIELDS Copper Target 1000 63Cu(d,p) 64Cu 65Cu(d,p)66Cu o 100 6...activation of 1 5 Zn by deuterons and for the GCZn(d,n)"Ga, ’,IZn(d,p)60 Zn, 6SZn(d,p)69mZn, 6 6 Zn(d,(X) 64Cu , and 68Zn(d,2n)6,8Ga reactions in a natural zinc target. 45

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

PubMed Central

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

1996-01-01

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

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

PubMed

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

2005-08-01

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

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

PubMed Central

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

2005-01-01

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

Variation in copper and zinc tolerance and accumulation in 12 willow clones: implications for phytoextraction*

PubMed Central

Yang, Wei-dong; Wang, Yu-yan; Zhao, Feng-liang; Ding, Zhe-li; Zhang, Xin-cheng; Zhu, Zhi-qiang; Yang, Xiao-e

2014-01-01

Willows (Salix spp.) have shown high potential for the phytoextraction of heavy metals. This study compares variations in copper (Cu) and zinc (Zn) tolerance and accumulation potential among 12 willow clones grown in a nutrient solution treated with 50 μmol/L of Cu or Zn, respectively. The results showed differences in the tolerance and accumulation of Cu and Zn with respect to different species/clones. The biomass variation among clones in response to Cu or Zn exposure ranged from the stimulation of growth to inhibition, and all of the clones tested showed higher tolerance to Cu than to Zn. The clones exhibited less variation in Cu accumulation but larger variation in Zn accumulation. Based on translocation factors, it was found that most of the Cu was retained in the roots and that Zn was more mobile than Cu for all clones. It is concluded that most willow clones are good accumulators of Zn and Cu. PMID:25183033

Electrodeposition of CuZn Alloys from the Non-Cyanide Alkaline Baths

NASA Astrophysics Data System (ADS)

Li, Minggang; Wei, Guoying; Hu, Shuangshuang; Xu, Shuhan; Yang, Yejiong; Miao, Qinfang

2015-10-01

Effect of copper sulfate on CuZn alloys electroplating from non-cyanide baths are investigated by different electrochemical methods. Cyclic voltammetry and current transient measurements are used to characterize the CuZn alloys electroplating system in order to analyze the nucleation and growth mechanism. The reduction of Cu and CuZn alloy on sheet iron substrates shows an instantaneous nucleation process. However, the reduction of Zn on sheet iron substrates shows a progressive nucleation process. The structure and surface morphology of CuZn alloys are analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The morphology of CuZn alloys obtained with 50 g L-1 copper sulfate presents a smooth and compact deposit and the size of crystal particle is uniform.

Colloidal synthesis of Cu-ZnO and Cu@CuNi-ZnO hybrid nanocrystals with controlled morphologies and multifunctional properties

NASA Astrophysics Data System (ADS)

Zeng, Deqian; Gong, Pingyun; Chen, Yuanzhi; Zhang, Qinfu; Xie, Qingshui; Peng, Dong-Liang

2016-06-01

Metal-semiconductor hybrid nanocrystals have received extensive attention owing to their multiple functionalities which can find wide technological applications. The utilization of low-cost non-noble metals to construct novel metal-semiconductor hybrid nanocrystals is important and meaningful for their large-scale applications. In this study, a facile solution approach is developed for the synthesis of Cu-ZnO hybrid nanocrystals with well-controlled morphologies, including nanomultipods, core-shell nanoparticles, nanopyramids and core-shell nanowires. In the synthetic strategy, Cu nanocrystals formed in situ serve as seeds for the heterogeneous nucleation and growth of ZnO, and it eventually forms various Cu-ZnO hetero-nanostructures under different reaction conditions. These hybrid nanocrystals possess well-defined and stable heterostructure junctions. The ultraviolet-visible-near infrared spectra reveal morphology-dependent surface plasmon resonance absorption of Cu and the band gap absorption of ZnO. Furthermore, we construct a novel Cu@CuNi-ZnO ternary hetero-nanostructure by incorporating the magnetic metal Ni into the pre-synthesized colloidal Cu nanocrystals. Such hybrid nanocrystals possess a magnetic Cu-Ni intermediate layer between the ZnO shell and the Cu core, and exhibit ferromagnetic/superparamagnetic properties which expand their functionalities. Finally, enhanced photocatalytic activities are observed in the as-prepared non-noble metal-ZnO hybrid nanocrystals. This study not only provides an economical way to prepare high-quality morphology-controlled Cu-ZnO hybrid nanocrystals for potential applications in the fields of photocatalysis and photovoltaic devices, but also opens up new opportunities in designing ternary non-noble metal-semiconductor hybrid nanocrystals with multifunctionalities.Metal-semiconductor hybrid nanocrystals have received extensive attention owing to their multiple functionalities which can find wide technological applications. The utilization of low-cost non-noble metals to construct novel metal-semiconductor hybrid nanocrystals is important and meaningful for their large-scale applications. In this study, a facile solution approach is developed for the synthesis of Cu-ZnO hybrid nanocrystals with well-controlled morphologies, including nanomultipods, core-shell nanoparticles, nanopyramids and core-shell nanowires. In the synthetic strategy, Cu nanocrystals formed in situ serve as seeds for the heterogeneous nucleation and growth of ZnO, and it eventually forms various Cu-ZnO hetero-nanostructures under different reaction conditions. These hybrid nanocrystals possess well-defined and stable heterostructure junctions. The ultraviolet-visible-near infrared spectra reveal morphology-dependent surface plasmon resonance absorption of Cu and the band gap absorption of ZnO. Furthermore, we construct a novel Cu@CuNi-ZnO ternary hetero-nanostructure by incorporating the magnetic metal Ni into the pre-synthesized colloidal Cu nanocrystals. Such hybrid nanocrystals possess a magnetic Cu-Ni intermediate layer between the ZnO shell and the Cu core, and exhibit ferromagnetic/superparamagnetic properties which expand their functionalities. Finally, enhanced photocatalytic activities are observed in the as-prepared non-noble metal-ZnO hybrid nanocrystals. This study not only provides an economical way to prepare high-quality morphology-controlled Cu-ZnO hybrid nanocrystals for potential applications in the fields of photocatalysis and photovoltaic devices, but also opens up new opportunities in designing ternary non-noble metal-semiconductor hybrid nanocrystals with multifunctionalities. Electronic supplementary information (ESI) available: Synthesis and TEM images of pure ZnO nanocrystals. Photocatalytic testing procedures and degradation curves. SEM and TEM images, SAED pattern and EDS spectra and maps of parts of Cu-ZnO hybrid samples. A schematic image of coincident lattice matching between Cu and ZnO. STEM-EDS elemental maps and XRD pattern of the Cu@CuNi-ZnO sample. Comparative synthetic parameters. See DOI: 10.1039/c6nr02055k

Effects of dietary zinc, iron, and copper in layer feed on distribution of these elements in eggs, liver, excreta, soil, and herbage.

PubMed

Skrivan, M; Skrivanová, V; Marounek, M

2005-10-01

An experiment was conducted to evaluate the effect of dietary content and combinations of Zn, Fe, and Cu on deposition of these elements in egg components, liver, and excreta. Excreta were applied as a manure to a lawn, and 3 mo later soil and herbage samples were taken and analyzed. The experiment comprised 144 hens in 8 groups. The basal diet contained Zn, Fe, and Cu at 63.4, 92.8, and 9.0 mg/kg, respectively. It was supplemented with 1, 2, or 3 trace elements (inorganic forms) at 80 mg of Zn/kg, 120 mg of Fe/kg, and 25 mg of Cu/kg. Recovery of Zn, Fe, and Cu in eggs of hens fed the basal diet was 10.7, 9.8, and 4.4% of the alimentary intake, respectively. A Zn-Cu antagonism was observed; deposition of Zn in the yolk was significantly decreased by Cu addition and vice versa (P < 0.01). Supplementation of the basal diet with Fe increased Fe concentration in egg yolk and white by 6.3 and 2.2%, respectively. The combination of Fe with Zn and Cu, however, increased Fe concentration in the yolk and white by 36.7 and 34.9%, respectively (P < 0.01). The enrichment of eggs with the other elements was marginal (Cu) or absent (Zn). Effects of Zn, Fe, and Cu of the basal diet on liver concentrations of these elements were relatively small, and no antagonism between Zn and Cu was apparent. Supplementation of the basal diet with the combination of Zn and Fe, however, significantly decreased hepatic concentration of Cu. On the other hand, Cu supplementation significantly increased Fe concentration in livers of hens fed the Fe-supplemented diet (P < 0.01). Concentrations of Zn, Fe, and Cu in excreta were related to their dietary content. High concentrations of Zn, Fe, and Cu in excreta corresponded with limited deposition of the 3 elements in eggs and liver. Concentrations of Zn, Fe, and Cu in herbage correlated significantly with the supply of these elements by hen excreta into soil. The Zn supplied by hen excreta was more stable than Fe and Cu; thus Zn could accumulate in the soil.

Structural and elemental characterization of high efficiency Cu2ZnSnS4 solar cells

NASA Astrophysics Data System (ADS)

Wang, Kejia; Shin, Byungha; Reuter, Kathleen B.; Todorov, Teodor; Mitzi, David B.; Guha, Supratik

2011-01-01

We have carried out detailed microstructural studies of phase separation and grain boundary composition in Cu2ZnSnS4 based solar cells. The absorber layer was fabricated by thermal evaporation followed by post high temperature annealing on hot plate. We show that inter-reactions between the bottom molybdenum and the Cu2ZnSnS4, besides triggering the formation of interfacial MoSx, results in the out-diffusion of Cu from the Cu2ZnSnS4 layer. Phase separation of Cu2ZnSnS4 into ZnS and a Cu-Sn-S compound is observed at the molybdenum-Cu2ZnSnS4 interface, perhaps as a result of the compositional out-diffusion. Additionally, grain boundaries within the thermally evaporated absorber layer are found to be either Cu-rich or at the expected bulk composition. Such interfacial compound formation and grain boundary chemistry likely contributes to the lower than expected open circuit voltages observed for the Cu2ZnSnS4 devices.

Hydrogenation of CO 2 on ZnO/Cu(100) and ZnO/Cu(111) Catalysts: Role of Copper Structure and Metal–Oxide Interface in Methanol Synthesis

DOE PAGES

Palomino, Robert M.; Ramirez, Pedro J.; Liu, Zongyuan; ...

2017-08-21

The results of kinetic tests and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) show the important role played by a ZnO–copper interface in the generation of CO and the synthesis of methanol from CO 2 hydrogenation. The deposition of nanoparticles of ZnO on Cu(100) and Cu(111), θ oxi < 0.3 monolayer, produces highly active catalysts. The catalytic activity of these systems increases in the sequence: Cu(111) < Cu(100) < ZnO/Cu(111) < ZnO/Cu(100). The structure of the copper substrate influences the catalytic performance of a ZnO–copper interface. Furthermore, size and metal–oxide interactions affect the chemical and catalytic properties of the oxide making themore » supported nanoparticles different from bulk ZnO. The formation of a ZnO–copper interface favors the binding and conversion of CO 2 into a formate intermediate that is stable on the catalyst surface up to temperatures above 500 K. Alloys of Zn with Cu(111) and Cu(100) were not stable at the elevated temperatures (500–600 K) used for the CO 2 hydrogenation reaction. However, reaction with CO 2 oxidized the zinc, enhancing its stability over the copper substrates.« less

Hydrogenation of CO 2 on ZnO/Cu(100) and ZnO/Cu(111) Catalysts: Role of Copper Structure and Metal–Oxide Interface in Methanol Synthesis

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

Palomino, Robert M.; Ramirez, Pedro J.; Liu, Zongyuan

The results of kinetic tests and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) show the important role played by a ZnO–copper interface in the generation of CO and the synthesis of methanol from CO 2 hydrogenation. The deposition of nanoparticles of ZnO on Cu(100) and Cu(111), θ oxi < 0.3 monolayer, produces highly active catalysts. The catalytic activity of these systems increases in the sequence: Cu(111) < Cu(100) < ZnO/Cu(111) < ZnO/Cu(100). The structure of the copper substrate influences the catalytic performance of a ZnO–copper interface. Furthermore, size and metal–oxide interactions affect the chemical and catalytic properties of the oxide making themore » supported nanoparticles different from bulk ZnO. The formation of a ZnO–copper interface favors the binding and conversion of CO 2 into a formate intermediate that is stable on the catalyst surface up to temperatures above 500 K. Alloys of Zn with Cu(111) and Cu(100) were not stable at the elevated temperatures (500–600 K) used for the CO 2 hydrogenation reaction. However, reaction with CO 2 oxidized the zinc, enhancing its stability over the copper substrates.« less

Effects of swift heavy ion irradiation on structural, optical and photocatalytic properties of ZnO–CuO nanocomposites prepared by carbothermal evaporation method

PubMed Central

Kuriakose, Sini; Avasthi, D K

2015-01-01

Summary ZnO–CuO nanocomposite thin films were prepared by carbothermal evaporation of ZnO and Cu, combined with annealing. The effects of 90 MeV Ni7+ ion irradiation on the structural and optical properties of ZnO–CuO nanocomposites were studied by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), UV–visible absorption spectroscopy and Raman spectroscopy. XRD studies showed the presence of ZnO and CuO nanostructures in the nanocomposites. FESEM images revealed the presence of nanosheets and nanorods in the nanocomposites. The photocatalytic activity of ZnO–CuO nanocomposites was evaluated on the basis of degradation of methylene blue (MB) and methyl orange (MO) dyes under sun light irradiation and it was observed that swift heavy ion irradiation results in significant enhancement in the photocatalytic efficiency of ZnO–CuO nanocomposites towards degradation of MB and MO dyes. The possible mechanism for the enhanced photocatalytic activity of ZnO–CuO nanocomposites is proposed. We attribute the observed enhanced photocatalytic activity of ZnO–CuO nanocomposites to the combined effects of improved sun light utilization and suppression of the recombination of photogenerated charge carriers in ZnO–CuO nanocomposites. PMID:25977864

Intrinsic point defects in off-stoichiometric Cu2ZnSnSe4: A neutron diffraction study

NASA Astrophysics Data System (ADS)

Gurieva, Galina; Valle Rios, Laura Elisa; Franz, Alexandra; Whitfield, Pamela; Schorr, Susan

2018-04-01

This work is an experimental study of intrinsic point defects in off-stoichiometric kesterite type CZTSe by means of neutron powder diffraction. We revealed the existence of copper vacancies (VCu), various cation anti site defects (CuZn, ZnCu, ZnSn, SnZn, and CuZn), as well as interstitials (Cui, Zni) in a wide range of off-stoichiometric polycrystalline powder samples synthesized by the solid state reaction. The results show that the point defects present in off-stoichiometric CZTSe agree with the off-stoichiometry type model, assuming certain cation substitutions accounting for charge balance. In addition to the known off-stoichiometry types A-H, new types (I-L) have been introduced. For the very first time, a correlation between the chemical composition of the CZTSe kesterite type phase and the occurring intrinsic point defects is presented. In addition to the off-stoichiometry type specific defects, the Cu/Zn disorder is always present in the CZTSe phase. In Cu-poor/Zn-rich CZTSe, a composition considered as the one that delivers the best photovoltaic performance, mainly copper vacancies, ZnCu and ZnSn anti sites are present. Also, this compositional region shows the lowest degree of Cu/Zn disorder.

Effects of CuZnAl Particles on Properties and Microstructure of Sn-58Bi Solder

PubMed Central

Yang, Fan; Zhang, Liang; Liu, Zhi-quan; Zhong, Su Juan; Ma, Jia; Bao, Li

2017-01-01

With the purpose of improving the properties of the Sn-58Bi lead-free solder, micro-CuZnAl particles ranging from 0 to 0.4 wt % were added into the low temperature eutectic Sn-58Bi lead-free solder. After the experimental testing of micro-CuZnAl particles on the properties and microstructure of the Sn-58Bi solders, it was found that the wettability of the Sn-58Bi solders was obviously improved with addition of CuZnAl particles. When the addition of CuZnAl particles was 0.2 wt %, the wettability of the Sn-58Bi solder performed best. At the same time, excessive addition of CuZnAl particles led to poor wettability. However, the results showed that CuZnAl particles changed the melting point of the Sn-58Bi solder slightly. The microstructure of the Sn-58Bi solder was refined by adding CuZnAl particles. When the content of CuZnAl addition was between 0.1 and 0.2 wt %, the refinement was great. In addition, the interfacial IMC layer between new composite solder and Cu substrate was thinner than that between the Sn-58Bi solder and Cu substrate. PMID:28772917

Structure and backbone dynamics of a microcrystalline metalloprotein by solid-state NMR.

PubMed

Knight, Michael J; Pell, Andrew J; Bertini, Ivano; Felli, Isabella C; Gonnelli, Leonardo; Pierattelli, Roberta; Herrmann, Torsten; Emsley, Lyndon; Pintacuda, Guido

2012-07-10

We introduce a new approach to improve structural and dynamical determination of large metalloproteins using solid-state nuclear magnetic resonance (NMR) with (1)H detection under ultrafast magic angle spinning (MAS). The approach is based on the rapid and sensitive acquisition of an extensive set of (15)N and (13)C nuclear relaxation rates. The system on which we demonstrate these methods is the enzyme Cu, Zn superoxide dismutase (SOD), which coordinates a Cu ion available either in Cu(+) (diamagnetic) or Cu(2+) (paramagnetic) form. Paramagnetic relaxation enhancements are obtained from the difference in rates measured in the two forms and are employed as structural constraints for the determination of the protein structure. When added to (1)H-(1)H distance restraints, they are shown to yield a twofold improvement of the precision of the structure. Site-specific order parameters and timescales of motion are obtained by a gaussian axial fluctuation (GAF) analysis of the relaxation rates of the diamagnetic molecule, and interpreted in relation to backbone structure and metal binding. Timescales for motion are found to be in the range of the overall correlation time in solution, where internal motions characterized here would not be observable.

Phytotoxic effects of Cu and Zn on soybeans grown in field-aged soils: their additive and interactive actions.

PubMed

Kim, Bojeong; McBride, Murray B

2009-01-01

A field pot experiment was conducted to investigate the interactive phytotoxicity of soil Cu and Zn on soybean plants [Glycine max (L.) Merr.]. Two soils (Arkport sandy loam [coarse-loamy, mixed, active, mesic Lamellic Hapludalf] and Hudson silty clay loam [fine, illitic, mesic Glossaquic Hapludalf]) spiked with Cu, Zn, and combinations of both to reach the final soil metal range of 0 to 400 mg kg(-1) were tested in a 2-yr bioassay after 1 yr of soil-metal equilibration in the field. The soluble and easily-extractable fraction of soil Zn (or Cu), estimated by dilute CaCl2, increased linearly in response to the total Zn (or Cu) added. This linearity was, however, strongly affected where soils were treated with both metals in combination, most notably for Zn, as approximately 50% more of soil Zn was extracted into solution when the Cu level was high. Consequently, added Zn is less likely to be stabilized by aging than added Cu when both metals are present in field soils. The predictive model relating soil metal extractability to plant Zn concentration also revealed a significant Cu-Zn interaction. By contrast, the interaction between the two metals contributed little to explain plant Cu uptake. The additive action of soil Cu and Zn was of considerable importance in explaining plant biomass reduction. This work clearly demonstrates the critical roles of the properties of the soil, the nature of the metal, and the level of other toxic metals present on the development of differential phytotoxicity due to soil Cu and Zn.

Fractionation of Cu and Zn isotopes during adsorption onto amorphous Fe(III) oxyhydroxide: Experimental mixing of acid rock drainage and ambient river water

USGS Publications Warehouse

Balistrieri, L.S.; Borrok, D.M.; Wanty, R.B.; Ridley, W.I.

2008-01-01

Fractionation of Cu and Zn isotopes during adsorption onto amorphous ferric oxyhydroxide is examined in experimental mixtures of metal-rich acid rock drainage and relatively pure river water and during batch adsorption experiments using synthetic ferrihydrite. A diverse set of Cu- and Zn-bearing solutions was examined, including natural waters, complex synthetic acid rock drainage, and simple NaNO3 electrolyte. Metal adsorption data are combined with isotopic measurements of dissolved Cu (65Cu/63Cu) and Zn (66Zn/64Zn) in each of the experiments. Fractionation of Cu and Zn isotopes occurs during adsorption of the metal onto amorphous ferric oxyhydroxide. The adsorption data are modeled successfully using the diffuse double layer model in PHREEQC. The isotopic data are best described by a closed system, equilibrium exchange model. The fractionation factors (??soln-solid) are 0.99927 ?? 0.00008 for Cu and 0.99948 ?? 0.00004 for Zn or, alternately, the separation factors (??soln-solid) are -0.73 ?? 0.08??? for Cu and -0.52 ?? 0.04??? for Zn. These factors indicate that the heavier isotope preferentially adsorbs onto the oxyhydroxide surface, which is consistent with shorter metal-oxygen bonds and lower coordination number for the metal at the surface relative to the aqueous ion. Fractionation of Cu isotopes also is greater than that for Zn isotopes. Limited isotopic data for adsorption of Cu, Fe(II), and Zn onto amorphous ferric oxyhydroxide suggest that isotopic fractionation is related to the intrinsic equilibrium constants that define aqueous metal interactions with oxyhydroxide surface sites. Greater isotopic fractionation occurs with stronger metal binding by the oxyhydroxide with Cu > Zn > Fe(II).

Chemical fractionation of Cu and Zn in stormwater, roadway dust and stormwater pond sediments

USGS Publications Warehouse

Camponelli, Kimberly M.; Lev, Steven M.; Snodgrass, Joel W.; Landa, Edward R.; Casey, Ryan E.

2010-01-01

This study evaluated the chemical fractionation of Cu and Zn from source to deposition in a stormwater system. Cu and Zn concentrations and chemical fractionation were determined for roadway dust, roadway runoff and pond sediments. Stormwater Cu and Zn concentrations were used to generate cumulative frequency distributions to characterize potential exposure to pond-dwelling organisms. Dissolved stormwater Zn exceeded USEPA acute and chronic water quality criteria in approximately 20% of storm samples and 20% of the storm duration sampled. Dissolved Cu exceeded the previously published chronic criterion in 75% of storm samples and duration and exceeded the acute criterion in 45% of samples and duration. The majority of sediment Cu (92–98%) occurred in the most recalcitrant phase, suggesting low bioavailability; Zn was substantially more available (39–62% recalcitrant). Most sediment concentrations for Cu and Zn exceeded published threshold effect concentrations and Zn often exceeded probable effect concentrations in surface sediments.

A facile green antisolvent approach to Cu2+-doped ZnO nanocrystals with visible-light-responsive photoactivities.

PubMed

Lu, Yi-Hsuan; Lin, Wei-Hao; Yang, Chao-Yao; Chiu, Yi-Hsuan; Pu, Ying-Chih; Lee, Min-Han; Tseng, Yuan-Chieh; Hsu, Yung-Jung

2014-08-07

An environmentally benign antisolvent method has been developed to prepare Cu(2+)-doped ZnO nanocrystals with controllable dopant concentrations. A room temperature ionic liquid, known as a deep eutectic solvent (DES), was used as the solvent to dissolve ZnO powders. Upon the introduction of the ZnO-containing DES into a bad solvent which shows no solvation to ZnO, ZnO was precipitated and grown due to the dramatic decrease of solubility. By adding Cu(2+) ions to the bad solvent, the growth of ZnO from the antisolvent process was accompanied by Cu(2+) introduction, resulting in the formation of Cu(2+)-doped ZnO nanocrystals. The as-prepared Cu(2+)-doped ZnO showed an additional absorption band in the visible range (400-800 nm), which conduced to an improvement in the overall photon harvesting efficiency. Time-resolved photoluminescence spectra, together with the photovoltage information, suggested that the doped Cu(2+) may otherwise trap photoexcited electrons during the charge transfer process, inevitably depressing the photoconversion efficiency. The photoactivity of Cu(2+)-doped ZnO nanocrystals for photoelectrochemical water oxidation was effectively enhanced in the visible region, which achieved the highest at 2.0 at% of Cu(2+). A further increase in the Cu(2+) concentration however led to a decrease in the photocatalytic performance, which was ascribed to the significant carrier trapping caused by the increased states given by excessive Cu(2+). The photocurrent action spectra illustrated that the enhanced photoactivity of the Cu(2+)-doped ZnO nanocrystals was mainly due to the improved visible photon harvesting achieved by Cu(2+) doping. These results may facilitate the use of transition metal ion-doped ZnO in other photoconversion applications, such as ZnO based dye-sensitized solar cells and magnetism-assisted photocatalytic systems.

Impaired zinc and copper status in children with burn injuries: need to reassess nutritional requirements.

PubMed

Voruganti, V Saroja; Klein, Gordon L; Lu, Hong-Xing; Thomas, Suchmor; Freeland-Graves, Jeanne H; Herndon, David N

2005-09-01

Major burns are associated with impaired Zn and Cu status. These micronutrients are essential for bone matrix formation, linear growth, and wound healing. This study evaluated the status of Zn and Cu in burned children and assessed adequacy of supplementation. Six children, mean total body surface area (TBSA), 54+/-9% (S.D.), were recruited. Nutrient intakes, plasma, wound exudate, and 24h urine samples were collected and analyzed for Zn and Cu. Bone mineral content was assessed by dual energy X-ray absorptiometry. Dietary Zn and Cu were three times the dietary reference, and mean plasma concentrations of Zn and Cu were low at admission and discharge. Urinary Zn was elevated at admission, whereas Cu was elevated at both times. Wound Zn and Cu concentrations exceeded plasma concentrations, suggesting that inflammatory wound exudate was a primary route of loss. We demonstrate that burn injury in children results in low plasma levels of Zn and Cu that are inadequately compensated during hospitalization.

Near room temperature and large-area synthesis of ZnO/Cu2O heterojunction for photocatalytic properties

NASA Astrophysics Data System (ADS)

Gao, Shiyong; Zhang, Jiejing; Li, Wenqiang; Jiao, Shujie; Nie, Yanguang; Fan, Huaiyun; Zeng, Zhi; Yu, Qingjiang; Wang, Jinzhong; Zhang, Xitian

2018-01-01

Large-area ZnO/Cu2O heterojunction have been successfully synthesized on Cu foil through a simple two-step solution method at near room temperature. The field emission scanning electron microscopy characterization indicates that the morphology of as-prepared Cu2O film grown on Cu foil is octahedral structure with diameter of ∼450 nm and ZnO is nanorod arrays structure with diameter of ∼150 nm. The current-voltage measurement of ZnO/Cu2O heterojunction shows a typical rectifying characteristics. Moreover, the photocatalytic test indicates that ZnO/Cu2O heterojunction exhibits high photocatalytic efficient for degradation of congo red dyes. The possible photocatalytic mechanism of ZnO/Cu2O heterojunction is also presented.

Cu-Doped ZnO Thin Films Grown by Co-deposition Using Pulsed Laser Deposition for ZnO and Radio Frequency Sputtering for Cu

NASA Astrophysics Data System (ADS)

Shin, Hyun Wook; Son, Jong Yeog

2018-05-01

Cu-doped ZnO (CZO) thin films were fabricated on single-crystalline (0001) Al2O3 substrates by co-deposition using pulsed laser deposition for ZnO and radio frequency sputtering for Cu. CZO thin films with 0-20% molar concentrations are obtained by adjusting the deposition rates of ZnO and Cu. The CZO thin films exhibit room temperature ferromagnetism, and CZO with 5% Cu molar concentration has maximum remanent magnetization, which is consistent with theoretical results.

Adsorption of multi-heavy metals Zn and Cu onto surficial sediments: modeling and adsorption capacity analysis.

PubMed

Li, Shanshan; Zhang, Chen; Wang, Meng; Li, Yu

2014-01-01

Improved multiple regression adsorption models (IMRAMs) was developed to estimate the adsorption capacity of the components [Fe oxides (Fe), Mn oxides (Mn), organic materials (OMs), residuals] in surficial sediments for multi-heavy metal Zn and Cu. IMRAM is an improved version over MRAM, which introduces a computer program in the model developing process. As MRAM, Zn(Cu) IMRAM, and Cu(Zn) IMRAM again confirmed that there is significant interaction effects that control the adsorption of compounded Zn and Cu, which was neglected by additional adsorption model. The verification experiment shows that the relative deviation of the IMRAMs is less than 13%. It is revealed by the IMRAMs that Mn, which has the greatest adsorption capability for compounded Zn and Cu (54.889 and 161.180 mg/l, respectively), follows by interference adsorption capacity of Fe/Mn (-1.072 and -24.591 mg/l respectively). Zn and Cu influence each other through different mechanisms. When Zn is the adsorbate, compounded Cu mainly affects the adsorption capacities of Fe/Mn and Fe/Mn/OMs; while when Cu is the adsorbate, compounded Zn mainly exerts its effect on Mn, Fe/Mn, and Mn/OMs. It also shows that the compounded Zn or Cu weakened the interference adsorption of Fe/Mn, and meanwhile, strengthened the interference adsorption of Mn/OMs.

Investigation of the 66Zn(p,2pn) 64Cu and 68Zn(p,x) 64Cu nuclear processes up to 100 MeV: Production of 64Cu

NASA Astrophysics Data System (ADS)

Szelecsényi, F.; Steyn, G. F.; Kovács, Z.; Vermeulen, C.; van der Meulen, N. P.; Dolley, S. G.; van der Walt, T. N.; Suzuki, K.; Mukai, K.

2005-11-01

Cross-sections of the 66Zn(p,2pn)64Cu and 68Zn(p,x)64Cu nuclear processes were measured on highly enriched zinc targets using the stacked-foil activation technique up to 100 MeV. The new cross-sections were compared to literature data. The optimum energy range for production of 64Cu was found to be 70 → 35 MeV on 66Zn and 37 → 20 MeV on 68Zn. The thick-target yields were determined as 777 MBq/μAh (21.0 mCi/μAh) and 185 MBq/μAh (5.0 mCi/μAh), respectively. The yields of the longer-lived contaminant copper radioisotopes (i.e. 61Cu when using 66Zn as target material and both 61Cu and 67Cu in the case of 68Zn target material) were also calculated. The results obtained from the present study indicate that both reactions are suited for the production of 64Cu at a medium energy cyclotron. The optimum energy ranges are also complementary therefore the potential to utilize tandem targetry exists.

Facile synthesis of core-shell Cu2O@ ZnO structure with enhanced photocatalytic H2 production

NASA Astrophysics Data System (ADS)

Zhang, Yong-Hui; Jiu, Bei-Bei; Gong, Fei-Long; Lu, Kuan; Jiang, Nan; Zhang, Hao-Li; Chen, Jun-Li

2018-05-01

Core-shell Cu2O@ZnO composites were synthesized successfully based on a one-pot hydrothermal method in the presence of dioctyl sulfosuccinate sodium salt (AOT) surfactant. The Cu2O can be converted to rough core-shell Cu2O@ZnO structure by adjusting the amount of zinc powder added. The as-synthesized Cu2O@ZnO composites exhibited excellent photocatalytic activity and the amount of H2 generated using these composites was 4.5-fold more than that produced with Cu2O cubes. A possible photocatalytic mechanism for the Cu2O@ZnO composites with enhanced photocatalytic activity could be the separation by ZnO of the effective charge carriers.

Simultaneous adsorption and degradation of Zn(2+) and Cu (2+) from wastewaters using nanoscale zero-valent iron impregnated with clays.

PubMed

Shi, Li-Na; Zhou, Yan; Chen, Zuliang; Megharaj, Mallavarapu; Naidu, Ravi

2013-06-01

Clays such as kaolin, bentonite and zeolite were evaluated as support material for nanoscale zero-valent iron (nZVI) to simultaneously remove Cu(2+) and Zn(2+) from aqueous solution. Of the three supported nZVIs, bentonite-supported nZVI (B-nZVI) was most effective in the simultaneous removal of Cu(2+) and Zn(2+) from a aqueous solution containing a 100 mg/l of Cu(2+) and Zn(2+), where 92.9 % Cu(2+) and 58.3 % Zn(2+) were removed. Scanning electronic microscope (SEM) revealed that the aggregation of nZVI decreased as the proportion of bentonite increased due to the good dispersion of nZVI, while energy dispersive spectroscopy (EDS) demonstrated the deposition of copper and zinc on B-nZVI after B-nZVI reacted with Cu(2+) and Zn(2+). A kinetics study indicated that removing Cu(2+) and Zn(2+) with B-nZVI accorded with the pseudo first-order model. These suggest that simultaneous adsorption of Cu(2+)and Zn(2+) on bentonite and the degradation of Cu(2+)and Zn(2+) by nZVI on the bentonite. However, Cu(2+) removal by B-nZVI was reduced rather than adsorption, while Zn(2+) removal was main adsorption. Finally, Cu(2+), Zn(2+), Ni(2+), Pb(2+) and total Cr from various wastewaters were removed by B-nZVI, and reusability of B-nZVI with different treatment was tested, which demonstrates that B-nZVI is a potential material for the removal of heavy metals from wastewaters.

Copper to Zinc Ratio as Disease Biomarker in Neonates with Early-Onset Congenital Infections

PubMed Central

Wisniewska, Monika; Cremer, Malte; Wiehe, Lennart; Becker, Niels-Peter; Rijntjes, Eddy; Martitz, Janine; Renko, Kostja; Bührer, Christoph; Schomburg, Lutz

2017-01-01

Copper (Cu) and zinc (Zn) are essential trace elements for regular development. Acute infections alter their metabolism, while deficiencies increase infection risks. A prospective observational case-control study was conducted with infected (n = 21) and control (n = 23) term and preterm newborns. We analyzed trace element concentrations by X-ray fluorescence, and ceruloplasmin (CP) by Western blot. Median concentration of Cu at birth (day 1) was 522.8 [387.1–679.7] μg/L, and Zn was 1642.4 ± 438.1 μg/L. Cu and Zn correlated positively with gestational age in control newborns. Cu increased in infected newborns from day 1 to day 3. CP correlated positively to Cu levels at birth in both groups and on day 3 in the group of infected neonates. The Cu/Zn ratio was relatively high in infected newborns. Interleukin (IL)-6 concentrations on day 1 were unrelated to Cu, Zn, or the Cu/Zn ratio, whereas C-reactive protein (CRP) levels on day 3 correlated positively to the Cu/Zn -ratio at both day 1 and day 3. We conclude that infections affect the trace element homeostasis in newborns: serum Zn is reduced, while Cu and CP are increased. The Cu/Zn ratio combines both alterations, independent of gestational age. It may, thus, constitute a meaningful diagnostic biomarker for early-onset infections. PMID:28358335

Simultaneous increase in strength and ductility by decreasing interface energy between Zn and Al phases in cast Al-Zn-Cu alloy.

PubMed

Han, Seung Zeon; Choi, Eun-Ae; Park, Hyun Woong; Lim, Sung Hwan; Lee, Jehyun; Ahn, Jee Hyuk; Hwang, Nong-Moon; Kim, Kwangho

2017-09-22

Cast-Al alloys that include a high amount of the second element in their matrix have comparatively high strength but low ductility because of the high volume fraction of strengthening phases or undesirable inclusions. Al-Zn alloys that have more than 30 wt% Zn have a tensile strength below 300 MPa, with elongation under 5% in the as-cast state. However, we found that after substitution of 2% Zn by Cu, the tensile strength of as-cast Al-Zn-Cu alloys was 25% higher and ductility was four times higher than for the corresponding Al-35% Zn alloy. Additionally, for the Al-43% Zn alloy with 2% Cu after 1 h solution treatment at 400 °C and water quenching, the tensile strength unexpectedly reached values close to 600 MPa. For the Al-33% Zn alloy with 2% Cu, the tensile strength was 500 MPa with 8% ductility. The unusual trends of the mechanical properties of Al-Zn alloys with Cu addition observed during processing from casting to the subsequent solution treatment were attributed to the precipitation of Zn in the Al matrix. The interface energy between the Zn particles and the Al matrix decreased when using a solution of Cu in Zn.

Ferulic acid prevents liver injury and increases the anti-tumor effect of diosbulbin B in vivo *

PubMed Central

Wang, Jun-ming; Sheng, Yu-chen; Ji, Li-li; Wang, Zheng-tao

2014-01-01

The present study is designed to investigate the protection by ferulic acid against the hepatotoxicity induced by diosbulbin B and its possible mechanism, and further observe whether ferulic acid augments diosbulbin B-induced anti-tumor activity. The results show that ferulic acid decreases diosbulbin B-increased serum alanine transaminase/aspartate transaminase (ALT/AST) levels. Ferulic acid also decreases lipid peroxide (LPO) levels which are elevated in diosbulbin B-treated mice. Histological evaluation of the liver demonstrates hydropic degeneration in diosbulbin B-treated mice, while ferulic acid reverses this injury. Moreover, the activities of copper- and zinc-containing superoxide dismutase (CuZn-SOD) and catalase (CAT) are decreased in the livers of diosbulbin B-treated mice, while ferulic acid reverses these decreases. Further results demonstrate that the mRNA expressions of CuZn-SOD and CAT in diosbulbin B-treated mouse liver are significantly decreased, while ferulic acid prevents this decrease. In addition, ferulic acid also augments diosbulbin B-induced tumor growth inhibition compared with diosbulbin B alone. Taken together, the present study shows that ferulic acid prevents diosbulbin B-induced liver injury via ameliorating diosbulbin B-induced liver oxidative stress injury and augments diosbulbin B-induced anti-tumor activity. PMID:24903991

Variation in oxidative stress indices of two green seaweeds growing under different heavy metal stresses.

PubMed

Ismail, Gehan A; Ismail, Mona M

2017-02-01

Concentrations of nine heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) were determined in the green seaweed species Cladophora glomerata and Ulva compressa collected from El-Mex and Sidi Kirayr locations. The heavy metal concentrations in algal tissues were in direct correlation with their soluble concentrations in seawater with the descending order: Fe

Colloidal synthesis of Cu-ZnO and Cu@CuNi-ZnO hybrid nanocrystals with controlled morphologies and multifunctional properties.

PubMed

Zeng, Deqian; Gong, Pingyun; Chen, Yuanzhi; Zhang, Qinfu; Xie, Qingshui; Peng, Dong-Liang

2016-06-02

Metal-semiconductor hybrid nanocrystals have received extensive attention owing to their multiple functionalities which can find wide technological applications. The utilization of low-cost non-noble metals to construct novel metal-semiconductor hybrid nanocrystals is important and meaningful for their large-scale applications. In this study, a facile solution approach is developed for the synthesis of Cu-ZnO hybrid nanocrystals with well-controlled morphologies, including nanomultipods, core-shell nanoparticles, nanopyramids and core-shell nanowires. In the synthetic strategy, Cu nanocrystals formed in situ serve as seeds for the heterogeneous nucleation and growth of ZnO, and it eventually forms various Cu-ZnO hetero-nanostructures under different reaction conditions. These hybrid nanocrystals possess well-defined and stable heterostructure junctions. The ultraviolet-visible-near infrared spectra reveal morphology-dependent surface plasmon resonance absorption of Cu and the band gap absorption of ZnO. Furthermore, we construct a novel Cu@CuNi-ZnO ternary hetero-nanostructure by incorporating the magnetic metal Ni into the pre-synthesized colloidal Cu nanocrystals. Such hybrid nanocrystals possess a magnetic Cu-Ni intermediate layer between the ZnO shell and the Cu core, and exhibit ferromagnetic/superparamagnetic properties which expand their functionalities. Finally, enhanced photocatalytic activities are observed in the as-prepared non-noble metal-ZnO hybrid nanocrystals. This study not only provides an economical way to prepare high-quality morphology-controlled Cu-ZnO hybrid nanocrystals for potential applications in the fields of photocatalysis and photovoltaic devices, but also opens up new opportunities in designing ternary non-noble metal-semiconductor hybrid nanocrystals with multifunctionalities.

Optical and electrical properties of copper-incorporated ZnS films applicable as solar cell absorbers

NASA Astrophysics Data System (ADS)

Mehrabian, M.; Esteki, Z.; Shokrvash, H.; Kavei, G.

2016-10-01

Un-doped and Cu-doped ZnS (ZnS:Cu) thin films were synthesized by Successive Ion Layer Absorption and Reaction (SILAR) method. The UV-visible absorption studies have been used to calculate the band gap values of the fabricated ZnS:Cu thin films. It was observed that by increasing the concentration of Cu2+ ions, the Fermi level moves toward the edge of the valence band of ZnS. Photoluminescence spectra of un-doped and Cu-doped ZnS thin films was recorded under 355 nm. The emission spectrum of samples has a blue emission band at 436 nm. The peak positions of the luminescence showed a red shift as the Cu2+ ion concentration was increased, which indicates that the acceptor level (of Cu2+) is getting close to the valence band of ZnS.

ZnO/Cu(InGa)Se.sub.2 solar cells prepared by vapor phase Zn doping

DOEpatents

Ramanathan, Kannan; Hasoon, Falah S.; Asher, Sarah E.; Dolan, James; Keane, James C.

2007-02-20

A process for making a thin film ZnO/Cu(InGa)Se.sub.2 solar cell without depositing a buffer layer and by Zn doping from a vapor phase, comprising: depositing Cu(InGa)Se.sub.2 layer on a metal back contact deposited on a glass substrate; heating the Cu(InGa)Se.sub.2 layer on the metal back contact on the glass substrate to a temperature range between about 100.degree. C. to about 250.degree. C.; subjecting the heated layer of Cu(InGa)Se.sub.2 to an evaporant species from a Zn compound; and sputter depositing ZnO on the Zn compound evaporant species treated layer of Cu(InGa)Se.sub.2.

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

NASA Astrophysics Data System (ADS)

Joshi, Ravi

2017-10-01

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

Copper transport and trafficking at the host-bacterial pathogen interface.

PubMed

Fu, Yue; Chang, Feng-Ming James; Giedroc, David P

2014-12-16

CONSPECTUS: The human innate immune system has evolved the means to reduce the bioavailability of first-row late d-block transition metal ions to invading microbial pathogens in a process termed "nutritional immunity". Transition metals from Mn(II) to Zn(II) function as metalloenzyme cofactors in all living cells, and the successful pathogen is capable of mounting an adaptive response to mitigate the effects of host control of transition metal bioavailability. Emerging evidence suggests that Mn, Fe, and Zn are withheld from the pathogen in classically defined nutritional immunity, while Cu is used to kill invading microorganisms. This Account summarizes new molecular-level insights into copper trafficking across cell membranes from studies of a number of important bacterial pathogens and model organisms, including Escherichia coli, Salmonella species, Mycobacterium tuberculosis, and Streptococcus pneumoniae, to illustrate general principles of cellular copper resistance. Recent highlights of copper chemistry at the host-microbial pathogen interface include the first high resolution structures and functional characterization of a Cu(I)-effluxing P1B-ATPase, a new class of bacterial copper chaperone, a fungal Cu-only superoxide dismutase SOD5, and the discovery of a small molecule Cu-bound SOD mimetic. Successful harnessing by the pathogen of host-derived bactericidal Cu to reduce the bacterial load of reactive oxygen species (ROS) is an emerging theme; in addition, recent studies continue to emphasize the importance of short lifetime protein-protein interactions that orchestrate the channeling of Cu(I) from donor to target without dissociation into bulk solution; this, in turn, mitigates the off-pathway effects of Cu(I) toxicity in both the periplasm in Gram negative organisms and in the bacterial cytoplasm. It is unclear as yet, outside of the photosynthetic bacteria, whether Cu(I) is trafficked to other cellular destinations, for example, to cuproenzymes or other intracellular storage sites, or the general degree to which copper chaperones vs copper efflux transporters are essential for bacterial pathogenesis in the vertebrate host. Future studies will be directed toward the identification and structural characterization of other cellular targets of Cu(I) trafficking and resistance, the physical and mechanistic characterization of Cu(I)-transfer intermediates, and elucidation of the mutual dependence of Cu(I) trafficking and cellular redox status on thiol chemistry in the cytoplasm. Crippling bacterial control of Cu(I) sensing, trafficking, and efflux may represent a viable strategy for the development of new antibiotics.

Room-temperature wide-range luminescence and structural, optical, and electrical properties of SILAR deposited Cu-Zn-S nano-structured thin films

NASA Astrophysics Data System (ADS)

Jose, Edwin; Kumar, M. C. Santhosh

2016-09-01

We report the deposition of nanostructured Cu-Zn-S composite thin films by Successive Ionic Layer Adsorption and Reaction (SILAR) method on glass substrates at room temperature. The structural, morphological, optical, photoluminescence and electrical properties of Cu-Zn-S thin films are investigated. The results of X-ray diffraction (XRD) and Raman spectroscopy studies indicate that the films exhibit a ternary Cu-Zn-S structure rather than the Cu xS and ZnS binary composite. Scanning electron microscope (SEM) studies show that the Cu-Zn-S films are covered well over glass substrates. The optical band gap energies of the Cu-Zn-S films are calculated using UV-visible absorption measurements, which are found in the range of 2.2 to 2.32 eV. The room temperature photoluminescence studies show a wide range of emissions from 410 nm to 565 nm. These emissions are mainly due to defects and vacancies in the composite system. The electrical studies using Hall effect measurements show that the Cu-Zn-S films are having p-type conductivity.

Microstructure and properties of Cu-Sn-Zn-TiO 2 nano-composite coatings on mild steel

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

Gao, Weidong; Cao, Di; Jin, Yunxue

Cu-Sn-Zn coatings have been widely used in industry for their unique properties, such as good conductivity, high corrosion resistance and excellent solderability. To further improve the mechanical performance of Cu-Sn-Zn coatings, powder-enhanced method was applied and Cu-Sn-Zn-TiO 2 nano-composite coatings with different TiO 2 concentration were fabricated. The microstructure of Cu-Sn-Zn-TiO 2 nano-composite coatings were investigated by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The mechanical properties of coatings including microhardness and wear resistance were studied. The results indicate that the incorporation of TiO 2 nanoparticle can significantly influence the properties of Cu-Sn-Zn coatings. The microhardness of Cu-Sn-Zn coatingmore » was increased to 383 HV from 330 HV with 1 g/L TiO 2 addition. Also, the corrosion resistance of coating was enhanced. The effects of TiO 2 nanoparticle concentration on the microstructure, mechanical properties and corrosion resistance of Cu-Sn-Zn-TiO 2 nano-composite coatings were discussed.« less

Microstructure and properties of Cu-Sn-Zn-TiO 2 nano-composite coatings on mild steel

DOE PAGES

Gao, Weidong; Cao, Di; Jin, Yunxue; ...

2018-04-18

Cu-Sn-Zn coatings have been widely used in industry for their unique properties, such as good conductivity, high corrosion resistance and excellent solderability. To further improve the mechanical performance of Cu-Sn-Zn coatings, powder-enhanced method was applied and Cu-Sn-Zn-TiO 2 nano-composite coatings with different TiO 2 concentration were fabricated. The microstructure of Cu-Sn-Zn-TiO 2 nano-composite coatings were investigated by X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The mechanical properties of coatings including microhardness and wear resistance were studied. The results indicate that the incorporation of TiO 2 nanoparticle can significantly influence the properties of Cu-Sn-Zn coatings. The microhardness of Cu-Sn-Zn coatingmore » was increased to 383 HV from 330 HV with 1 g/L TiO 2 addition. Also, the corrosion resistance of coating was enhanced. The effects of TiO 2 nanoparticle concentration on the microstructure, mechanical properties and corrosion resistance of Cu-Sn-Zn-TiO 2 nano-composite coatings were discussed.« less

Synthesis and characterization of Cu-Zn/TiO2 for the photocatalytic conversion of CO2 to methane.

PubMed

Rana, Adeem Ghaffar; Ahmad, Waqar; Al-Matar, Ali; Shawabkeh, Reyad; Aslam, Zaheer

2017-05-01

Different Cu-Zn/TiO 2 catalysts were synthesized by using the wet impregnation method. The prepared catalysts were used for the conversion of CO 2 into methane by photocatalysis. Various characterization techniques were used to observe the surface morphology, crystalline phase, Brunauer-Emmett-Teller (BET) surface area, presence of impregnated Cu and Zn, and functional group. Scanning electron microscope analysis showed spherical morphology, and slight agglomeration of catalyst particles was observed. BET analysis revealed that the surface area of the catalyst was decreased from 10 to 8.5 m 2 /g after impregnation of Cu and Zn over TiO 2 support. Synergetic effect of Cu and Zn over TiO 2 support (Cu 2.6 /TiO 2 , Zn 0.5 /TiO 2 and Cu 2.6 -Zn 0.5 /TiO 2 ) and the effects of Cu loading (0, 1.8, 2.1, 2.6 and 2.9 wt%) were also investigated at different feed molar ratios of H 2 /CO 2 (2:1 and 4:1). The Cu 2.6 -Zn 0.5 /TiO 2 catalyst showed a maximum conversion of 14.3% at a feed molar ratio of 4. The addition of Zn over the catalyst surface increased the conversion of CO 2 from 10% to 14.3% which might be due to synergy of Cu and Zn over TiO 2 support.

Trace amounts of Cu²⁺ ions influence ROS production and cytotoxicity of ZnO quantum dots.

PubMed

Moussa, Hatem; Merlin, Christophe; Dezanet, Clément; Balan, Lavinia; Medjahdi, Ghouti; Ben-Attia, Mossadok; Schneider, Raphaël

2016-03-05

3-Aminopropyltrimethoxysilane (APTMS) was used as ligand to prepare ZnO@APTMS, Cu(2+)-doped ZnO (ZnO:Cu@APTMS) and ZnO quantum dots (QDs) with chemisorbed Cu(2+) ions at their surface (ZnO@APTMS/Cu). The dots have a diameter of ca. 5 nm and their crystalline and phase purities and composition were established by X-ray diffraction, transmission electron microscopy, UV-visible and fluorescence spectroscopies and by X-ray photoelectron spectroscopy. The effect of Cu(2+) location on the ability of the QDs to generate reactive oxygen species (ROS) under light irradiation was investigated. Results obtained demonstrate that all dots are able to produce ROS (OH, O2(-), H2O2 and (1)O2) and that ZnO@APTMS/Cu QDs generate more OH and O2(-) radicals and H2O2 than ZnO@APTMS and ZnO:Cu@APTMS QDs probably via mechanisms associating photo-induced charge carriers and Fenton reactions. In cytotoxicity experiments conducted in the dark or under light exposure, ZnO@APTMS/Cu QDs appeared slightly more deleterious to Escherichia coli cells than the two other QDs, therefore pointing out the importance of the presence of Cu(2+) ions at the periphery of the nanocrystals. On the other hand, with the lack of photo-induced toxicity, it can be inferred that ROS production cannot explain the cytotoxicity associated to the QDs. Our study demonstrates that both the production of ROS from ZnO QDs and their toxicity may be enhanced by chemisorbed Cu(2+) ions, which could be useful for medical or photocatalytic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermochemistry of paddle wheel MOFs: Cu-HKUST-1 and Zn-HKUST-1.

PubMed

Bhunia, Manas K; Hughes, James T; Fettinger, James C; Navrotsky, Alexandra

2013-06-25

Metal-organic framework (MOF) porosity relies upon robust metal-organic bonds to retain structural rigidity upon solvent removal. Both the as-synthesized and activated Cu and Zn polymorphs of HKUST-1 were studied by room temperature acid solution calorimetry. Their enthalpies of formation from dense assemblages (metal oxide (ZnO or CuO), trimesic acid (TMA), and N,N-dimethylformamide (DMF)) were calculated from the calorimetric data. The enthalpy of formation (ΔHf) of the as-synthesized Cu-HKUST-H2O ([Cu3TMA2·3H2O]·5DMF) is -52.70 ± 0.34 kJ per mole of Cu. The ΔHf for Zn-HKUST-DMF ([Zn3TMA2·3DMF]·2DMF) is -54.22 ± 0.57 kJ per mole of Zn. The desolvated Cu-HKUST-dg [Cu3TMA2] has a ΔHf of 16.66 ± 0.51 kJ/mol per mole Cu. The ΔHf for Zn-HKUST-amorph [Zn3TMA2·2DMF] is -3.57 ± 0.21 kJ per mole of Zn. Solvent stabilizes the Cu-HKUST-H2O by -69.4 kJ per mole of Cu and Zn-HKUST-DMF by at least -50.7 kJ per mole of Zn. Such strong chemisorption of solvent is similar in magnitude to the strongly exothermic binding at low coverage for chemisorbed H2O on transition metal oxide nanoparticle surfaces. The strongly exothermic solvent-framework interaction suggests that solvent can play a critical role in obtaining a specific secondary building unit (SBU) topology.

The Cu2ZnSnSe4 thin films solar cells synthesized by electrodeposition route

NASA Astrophysics Data System (ADS)

Li, Ji; Ma, Tuteng; Wei, Ming; Liu, Weifeng; Jiang, Guoshun; Zhu, Changfei

2012-06-01

An electrodeposition route for preparing Cu2ZnSnSe4 thin films for thin film solar cell absorber layers is demonstrated. The Cu2ZnSnSe4 thin films are prepared by co-electrodeposition Cu-Zn-Sn metallic precursor and subsequently annealing in element selenium atmosphere. The structure, composition and optical properties of the films were investigated by X-ray diffraction (XRD), Raman spectrometry, energy dispersive spectrometry (EDS) and UV-VIS absorption spectroscopy. The Cu2ZnSnSe4 thin film with high crystalline quality was obtained, the band gap and absorption coefficient were 1.0 eV and 10-4 cm-1, which is quite suitable for solar cells fabrication. A solar cell with the structure of ZnO:Al/i-ZnO/CdS/Cu2ZnSnSe4/Mo/glass was fabricated and achieved an conversion efficiency of 1.7%.

Defect evolution and its impact on the ferromagnetism of Cu-doped ZnO nanocrystals upon thermal treatment: A positron annihilation study

NASA Astrophysics Data System (ADS)

Chen, Zhi-Yuan; Chen, Yuqian; Zhang, Q. K.; Qi, N.; Chen, Z. Q.; Wang, S. J.; Li, P. H.; Mascher, P.

2017-01-01

CuO/ZnO nanocomposites with 4 at. % CuO were annealed in air at various temperatures between 100 and 1200 °C to produce Cu-doped ZnO nanocrystals. X-ray diffraction shows that a CuO phase can be observed in the CuO/ZnO nanocomposites annealed at different temperatures, and the Cu-doped ZnO nanocrystals are identified to be of wurtzite structure. The main peak (101) appears at slightly lower diffraction angles with increasing annealing temperature from 400 up to 1200 °C, which confirms the successful doping of Cu into the ZnO lattice above 400 °C. Scanning electron microscopy indicates that most particles in the CuO/ZnO nanocomposites are isolated when annealing at 100-400 °C, but these particles have a tendency to form clusters or aggregates as the annealing temperature increases from 700 to 1000 °C. Positron annihilation measurements reveal a large number of vacancy defects in the interface region of the nanocomposites, and they are gradually recovered with increasing annealing temperature up to 1000 °C. Room-temperature ferromagnetism can be observed in the CuO/ZnO nanocomposites, and the magnetization decreases continuously with increasing annealing temperature. However, there may be several different origins of ferromagnetism in the CuO/ZnO nanocomposites. At low annealing temperatures, the ferromagnetism originates from the CuO nanograins, and the ferromagnetism of CuO nanograins decreases with an increase in the grain size after subsequent higher temperature annealing, which leads to the weakening of ferromagnetism in the CuO/ZnO nanocomposites. After annealing from 400 to 1000 °C, the ferromagnetism gradually vanishes. The ferromagnetism is probably induced by Cu substitution but is mediated by vacancy defects in the CuO/ZnO nanocomposites. The disappearance of ferromagnetism coincides well with the recovery of vacancy defects. It can be inferred that the ferromagnetism is mediated by vacancy defects that are distributed in the interface region.

Cyclotron production of 61Cu using natural Zn & enriched 64Zn targets

NASA Astrophysics Data System (ADS)

Asad, A. H.; Smith, S. V.; Chan, S.; Jeffery, C. M.; Morandeau, L.; Price, R. I.

2012-12-01

Copper-61 (61Cu) shares with 64Cu certain advantages for PET diagnostic imaging, but has a shorter half-life (3.4hr vs. 12.7hr) and a greater probability of positron production per disintegration (61% vs. 17.9%). One important application is for in vivo imaging of hypoxic tissue. In this study 61Cu was produced using the 64Zn(p,α)61Cu reaction on natural Zn or enriched 64Zn targets. The enriched 64Zn (99.82%) was electroplated onto high purity gold or silver foils or onto thin Al discs. A typical target bombardment used 30μA; at 11.7, 14.5 or 17.6MeV over 30-60min. The 61Cu (radiochemical purity of >95%) was separated using a combination of cation and anion exchange columns. The 64Zn target material was recovered after each run, for re-use. In a direct comparison with enriched 64Zn-target results, 61Cu production using the cheaper natZn target proved to be an effective alternative.

Effects of Cu(2+) and Zn(2+) on growth and physiological characteristics of green algae, Cladophora.

PubMed

Cao, De-ju; Xie, Pan-pan; Deng, Juan-wei; Zhang, Hui-min; Ma, Ru-xiao; Liu, Cheng; Liu, Ren-jing; Liang, Yue-gan; Li, Hao; Shi, Xiao-dong

2015-11-01

Effects of various concentrations of Cu(2+) and Zn(2+) (0.0, 0.1, 0.25, 0.5, or 1.0 mg/L) on the growth, malondialdehyde (MDA), the intracellular calcium, and physiological characteristics of green algae, Cladophora, were investigated. Low Zn(2+) concentrations accelerated the growth of Cladophora, whereas Zn(2+) concentration increases to 0.25 mg/L inhibited its growth. Cu(2+) greatly influences Cladophora growth. The photosynthesis of Cladophora decreased under Zn(2+) and Cu(2+) stress. Cu(2+) and Zn(2+) treatment affected the content of total soluble sugar in Cladophora and has small increases in its protein content. Zn(2+) induced the intracellular calcium release, and copper induced the intracellular calcium increases in Cladophora. Exposure to Cu(2+) and Zn(2+) induces MDA in Cladophora. The stress concent of Cu(2+) was strictly correlated with the total soluble sugar content, Chla+Chlb, and MDA in Cladophora, and the stress concent of Zn(2+) was strictly correlated with the relative growth rate (RGR) and MDA of Cladophora.

Cu-Zn isotope constraints on the provenance of air pollution in Central Europe: Using soluble and insoluble particles in snow and rime.

PubMed

Novak, Martin; Sipkova, Adela; Chrastny, Vladislav; Stepanova, Marketa; Voldrichova, Petra; Veselovsky, Frantisek; Prechova, Eva; Blaha, Vladimir; Curik, Jan; Farkas, Juraj; Erbanova, Lucie; Bohdalkova, Leona; Pasava, Jan; Mikova, Jitka; Komarek, Arnost; Krachler, Michael

2016-11-01

Copper (Cu) and zinc (Zn) isotope ratios can be used to fingerprint sources and dispersion pathways of pollutants in the environment. Little is known, however, about the potential of δ 65 Cu and δ 66 Zn values in liquid and solid forms of atmospheric deposition to distinguish between geogenic, industrial, local and remote sources of these potentially toxic base metals. Here we present Cu-Zn deposition fluxes at 10 mountain-top sites in the Czech Republic, a region affected by extremely high industrial emission rates 25 years ago. Additionally, we monitored isotope composition of Cu and Zn in vertical and horizontal atmospheric deposition at two sites. We compared δ 65 Cu and δ 66 Zn values in snow and rime, extracted by diluted HNO 3 and concentrated HF. Cu and Zn isotope signatures of industrial pollution sources were also determined. Cu and Zn deposition fluxes at all study sites were minute. The mean δ 65 Cu value of atmospheric deposition (-0.07‰) was higher than the mean δ 65 Cu value of pollution sources (-1.17‰). The variability in δ 65 Cu values of atmospheric deposition was lower, compared to the pollution sources. The mean δ 66 Zn value of atmospheric deposition (-0.09‰) was slightly higher than the mean δ 66 Zn value of pollution sources (-0.23‰). The variability in δ 66 Zn values of atmospheric deposition was indistinguishable from that of pollution sources. The largest isotope differences (0.35‰) were observed between the insoluble and soluble fractions of atmospheric deposition. These differences may result from different sources of Cu/Zn for each fraction. The difference in isotope composition of soluble and insoluble particles appears to be a promising tool for pollution provenance studies in Central Europe. Copyright © 2016 Elsevier Ltd. All rights reserved.

Changes in urinary Cu, Zn, and Se levels in cancer patients after treatment with Sha Shen Mai Men Dong Tang

PubMed Central

Lai, Tung-Yuan; Kuo, Hsien-Wen

2015-01-01

Sha Shen Mai Men Dong Tang (SMD-2; 沙參麥冬湯 shā shēn mài dōng tāng) is a Chinese medicinal herb (CMH; 中草藥 zhōng cǎo yào) used to treat symptoms associated with cancer therapy. The objective of this study was to assess the effect of SMD-2 on the levels of urinary copper (Cu), zinc (Zn), and selenium (Se) in lung cancer patients and head and neck cancer patients receiving chemoradiotherapy. Forty-two head and neck cancer patients and 10 lung cancer patients participated in our clinical trial. Each patient received chemoradiotherapy for 4 weeks. In addition, each patient was treated with SMD-2 for 8 weeks, including 2 weeks prior to and after the chemoradiotherapy treatment. Comparison of urinary Cu, Zn, and Se levels and the ratios of Zn to Cu and Se to Cu at three time points in the two types of cancer were assessed using the generalized estimating equations (GEEs). After the patients received chemoradiotherapy for 4 weeks, SMD-2 treatment was found to be associated with a significant decrease in urinary Cu levels, whereas urinary Zn and Se levels increased significantly. In addition, the ratios of Zn to Cu and Se to Cu in the urine samples of these patients also increased significantly. Both the urinary Zn levels and the ratio of Zn to Cu in head and neck cancer patients were significantly higher than in lung cancer patients. Urinary Zn and Se levels and the ratios of Zn to Cu and Se to Cu, but not urinary Cu levels, increased significantly during and after treatment when assessed using the GEE model. The SMD-2 treatments significantly increased Zn and Se levels in the urine of head and neck cancer patients. Increased Zn and Se levels in urine strengthened immune system. PMID:27114935

Luminescence, magnetic and vibrational properties of novel heterometallic niccolites [(CH3)2NH2][CrIIIMII(HCOO)6] (MII=Zn, Ni, Cu) and [(CH3)2NH2][AlIIIZnII(HCOO)6]:Cr3+

NASA Astrophysics Data System (ADS)

Mączka, Mirosław; Pietraszko, Adam; Pikul, Adam; Hermanowicz, Krzysztof

2016-01-01

We report synthesis of three novel heterometallic MOFs, [(CH3)2NH2][CrIIIMII(HCOO)6] with M=Zn (DMCrZn), Ni (DMCrNi) and Cu (DMCrCu), crystallizing in the niccolite type structure. We also successfully synthesized [(CH3)2NH2][AlCu(HCOO)6] (DMAlCu) and [(CH3)2NH2][AlZn(HCOO)6] doped with 5.8 mol% of Cr3+ (DMAlZn: Cr). X-ray diffraction shows that DMCrZn, DMCrNi and DMAlZn: Cr3+ crystallize in the trigonal structure (space group P 3 bar1c) while DMCrCu and DMAlCu crystallize in the monoclinic structure (space group C2/c). Magnetic investigation of the chromium-based niccolites reveals no magnetic order in DMCrZn and ferromagnetic order in DMCrNi and DMCrCu below 23 and 11 K, respectively. Optical studies show that DMCrZn and DMAlZn: Cr samples exhibit efficient emission typical for chromium ions located at sites of strong crystal field with the Dq/B values 2.62 and 2.67, respectively. We also discuss role of geometrical parameters in stability of the perovskite and niccolite structures.

First Measurement of the Radionuclide Purity of the Therapeutic Isotope 67Cu Produced by 68Zn(n,x) Reaction Using natC(d,n) Neutrons

NASA Astrophysics Data System (ADS)

Sato, Nozomi; Tsukada, Kazuaki; Watanabe, Satoshi; Ishioka, Noriko S.; Kawabata, Masako; Saeki, Hideya; Nagai, Yasuki; Kin, Tadahiro; Minato, Futoshi; Iwamoto, Nobuyuki; Iwamoto, Osamu

2014-07-01

We have for the first time studied the radionuclide purity of the therapeutic isotope 67Cu produced by the 68Zn(n,x)67Cu reaction. The neutrons were obtained by the natC(d,n) reaction using 40 MeV deuterons. We measured the γ-ray spectra of the reaction products produced by bombarding an enriched 68ZnO sample with the neutrons with a high-purity Ge detector. We found that the relative production yields of the impurity radionuclides 64Cu, 65Zn, and 69mZn to 67Cu are extremely low. The result indicates that the 68Zn(n,x)67Cu reaction is the most promising among those proposed routes until now for producing high-quality 67Cu, and could solve a longstanding problem of establishing an appropriate production method for 67Cu.

Visible light-driven photocatalytic H{sub 2}-generation activity of CuS/ZnS composite particles

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

Xiao, Liang; Chen, Hua; Huang, Jianhua, E-mail: jhhuang@zstu.edu.cn

2015-04-15

Highlights: • Preparation of CuS/ZnS composite photocatalyst by cation-exchange reaction. • Visible light photocatalytic activity for H{sub 2} evolution without cocatalyst. • The H{sub 2}-evolution rate from water splitting depends on the CuS content. • The highest rate of H{sub 2} evolution is obtained with CuS (0.5 mol%)/ZnS composite. - Abstract: CuS/ZnS composite particles with diameter of 200–400 nm were successfully prepared by a simple cation-exchange reaction using ZnS spheres as a precursor. CuS nanoparticles with a few nanometers in diameter were observed on the surface of composite particles. The synthesized CuS/ZnS composite particles showed photocatalytic property effective for H{submore » 2} evolution from an aqueous Na{sub 2}S and Na{sub 2}SO{sub 3} solution under visible light irradiation without any cocatalysts. The rate of H{sub 2} generation was found to be strongly dependent on the CuS content. The highest rate of H{sub 2} evolution reached 695.7 μmol h{sup −1} g{sup −1}, which was almost 7 times as high as that of the mechanical mixture of CuS and ZnS. The enhancement in the photocatalytic activity of CuS/ZnS composite particles is supposed to be due to the direct interfacial charge transfer of the CuS/ZnS heterojunction.« less

Synthesis and photoelectrochemical properties of a novel CuO/ZnO nanorod photocathode for solar hydrogen generation

NASA Astrophysics Data System (ADS)

Shaislamov, Ulugbek; Lee, Heon-Ju

2016-10-01

Here, we present a facile synthesis method and photoelectrochemical characterizations of a p-type CuO-nanorod array photoelectrode with ZnO nanorod branches. Vertically-aligned CuO nanorods were synthesized by using direct oxidation of metallic Cu nanorods grown on a Cu substrate by using a facile template-assisted electrodeposition method. The formed CuONR/ZnONB hierarchically-structured photoelectrode exhibited remarkable photoelectrodechemical performance and outstanding stability compared to the CuO NR photoelectrode without ZnO NR branches. Morphological, optical and electrochemical characterizations were carried out in order to examine the effects of ZnO nanorod branches on the stability and the overall electrochemical performance of the electrode.

Dilute electrodeposition of TiO2 and ZnO thin film memristors on Cu substrate

NASA Astrophysics Data System (ADS)

Fauzi, F. B.; Ani, M. H.; Herman, S. H.; Mohamed, M. A.

2018-03-01

Memristor has become one of the alternatives to replace the current memory technologies. Fabrication of titanium dioxide, TiO2 memristor has been extensively studied by using various deposition methods. However, recently more researches have been done to explore the compatibility of other transition metal oxide, TMO such as zinc oxide, ZnO to be used as the active layer of the memristor. This paper highlights the simple and easy-control electrodeposition to deposit titanium, Ti and zinc, Zn thin film at room temperature and subsequent thermal oxidation at 600 °C. Gold, Au was then sputtered as top electrode to create metal-insulator-metal, MIM sandwich of Au/TiO2-Cu2O-CuO/Cu and Au/ZnO-Cu2O-CuO/Cu memristors. The structural, morphological and memristive properties were characterized using Field Emission Scanning Electron Microscopy, FESEM, X-Ray Diffraction, XRD and current-voltage, I-V measurement. Both Au/TiO2-Cu2O-CuO/Cu and Au/ZnO-Cu2O-CuO/Cu memristivity were identified by the pinched hysteresis loop with resistive ratio of 1.2 and 1.08 respectively. Empirical study on diffusivity of Ti4+, Zn2+ and O2‑ ions in both metal oxides show that the metal vacancies were formed, thus giving rise to its memristivity. The electrodeposited Au/TiO2-Cu2O-CuO/Cu and Au/ZnO-Cu2O-CuO/Cu memristors demonstrate comparable performances to previous studies using other methods.

CuO and ZnO nanoparticles: phytotoxicity, metal speciation, and induction of oxidative stress in sand-grown wheat

NASA Astrophysics Data System (ADS)

Dimkpa, Christian O.; McLean, Joan E.; Latta, Drew E.; Manangón, Eliana; Britt, David W.; Johnson, William P.; Boyanov, Maxim I.; Anderson, Anne J.

2012-09-01

Metal oxide nanoparticles (NPs) are reported to impact plant growth in hydroponic systems. This study describes the impact of commercial CuO (<50 nm) and ZnO (<100 nm) NPs on wheat ( Triticum aestivum) grown in a solid matrix, sand. The NPs contained both metallic and non-metallic impurities to different extents. Dynamic light scattering and atomic force microscopy (AFM) assessments confirmed aggregation of the NPs to submicron sizes. AFM showed transformation of ZnO NPs from initial rhomboid shapes in water to elongated rods in the aqueous phase of the sand matrix. Solubilization of metals occurred in the sand at similar rates from CuO or ZnO NPs as their bulk equivalents. Amendment of the sand with 500 mg Cu and Zn/kg sand from the NPs significantly ( p = 0.05) reduced root growth, but only CuO NPs impaired shoot growth; growth reductions were less with the bulk amendments. Dissolved Cu from CuO NPs contributed to their phytotoxicity but Zn release did not account for the changes in plant growth. Bioaccumulation of Cu, mainly as CuO and Cu(I)-sulfur complexes, and Zn as Zn-phosphate was detected in the shoots of NP-challenged plants. Total Cu and Zn levels in shoot were similar whether NP or bulk materials were used. Oxidative stress in the NP-treated plants was evidenced by increased lipid peroxidation and oxidized glutathione in roots and decreased chlorophyll content in shoots; higher peroxidase and catalase activities were present in roots. These findings correlate with the NPs causing increased production of reactive oxygen species. The accumulation of Cu and Zn from NPs into edible plants has relevance to the food chain.

Elastocaloric effect in CuAlZn and CuAlMn shape memory alloys under compression

PubMed Central

Qian, Suxin; Wang, Yi; Pillsbury, Thomas E.; Hada, Yoshiharu; Yamaguchi, Yuki; Fujimoto, Kenjiro; Hwang, Yunho; Radermacher, Reinhard; Cui, Jun; Yuki, Yoji; Toyotake, Koutaro; Takeuchi, Ichiro

2016-01-01

This paper reports the elastocaloric effect of two Cu-based shape memory alloys: Cu68Al16Zn16 (CuAlZn) and Cu73Al15Mn12 (CuAlMn), under compression at ambient temperature. The compression tests were conducted at two different rates to approach isothermal and adiabatic conditions. Upon unloading at a strain rate of 0.1 s−1 (adiabatic condition) from 4% strain, the highest adiabatic temperature changes (ΔTad) of 4.0 K for CuAlZn and 3.9 K for CuAlMn were obtained. The maximum stress and hysteresis at each strain were compared. The stress at the maximum recoverable strain of 4.0% for CuAlMn was 120 MPa, which is 70% smaller than that of CuAlZn. A smaller hysteresis for the CuAlMn alloy was also obtained, about 70% less compared with the CuAlZn alloy. The latent heat, determined by differential scanning calorimetry, was 4.3 J g−1 for the CuAlZn alloy and 5.0 J g−1 for the CuAlMn alloy. Potential coefficients of performance (COPmat) for these two alloys were calculated based on their physical properties of measured latent heat and hysteresis, and a COPmat of approximately 13.3 for CuAlMn was obtained. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’. PMID:27402936

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

PubMed Central

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

2008-01-01

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

Use of Cu/Zn-superoxide dismutase tool for biomonitoring marine environment pollution in the Persian Gulf and the Gulf of Oman.

PubMed

Zeinali, Farrokhzad; Homaei, Ahmad; Kamrani, Ehsan; Patel, Seema

2018-04-30

Superoxide dismutase (SOD) is the pivotal antioxidant enzyme that defends organisms against the oxidative stresses of superoxide radicals. In this experimental study, purification of SOD from the leaves of Avicennia marina (grey mangrove or white mangrove) from the family Acanthaceae, located in Sirik mangrove forest on the shore of the Gulf of Oman was performed, for the intended characterization of SOD. The Sirik AmSOD (A. marina SOD) expressed optimum activity in the pH range of 6-9 with the maximum activity at pH 8. The optimal temperature for Sirik AmSOD activity was 70°C. Comparison of the pH and temperature optima in two regions (the Persian Gulf and the Gulf of Oman) showed significant differences with P<0.05. The SOD from the Persian Gulf was more resistant against the environmental stressors, because of the biochemical adaption to this environment, which is harsher. The evidence from these results suggests that AmSOD has different characteristics in each place, and mangroves undergo different adaptations and require different protections. The results of the enzymatic research can be useful for ecological management of organisms. Copyright © 2018 Elsevier Inc. All rights reserved.

Isotopic variations of dissolved copper and zinc in stream waters affected by historical mining

USGS Publications Warehouse

Borrok, D.M.; Nimick, D.A.; Wanty, R.B.; Ridley, W.I.

2008-01-01

Zinc and Cu play important roles in the biogeochemistry of natural systems, and it is likely that these interactions result in mass-dependent fractionations of their stable isotopes. In this study, we examine the relative abundances of dissolved Zn and Cu isotopes in a variety of stream waters draining six historical mining districts located in the United States and Europe. Our goals were to (1) determine whether streams from different geologic settings have unique or similar Zn and Cu isotopic signatures and (2) to determine whether Zn and Cu isotopic signatures change in response to changes in dissolved metal concentrations over well-defined diel (24-h) cycles. Average ??66Zn and ??65Cu values for streams varied from +0.02??? to +0.46??? and -0.7??? to +1.4???, respectively, demonstrating that Zn and Cu isotopes are heterogeneous among the measured streams. Zinc or Cu isotopic changes were not detected within the resolution of our measurements over diel cycles for most streams. However, diel changes in Zn isotopes were recorded in one stream where the fluctuations of dissolved Zn were the largest. We calculate an apparent separation factor of ???0.3??? (66/64Zn) between the dissolved and solid Zn reservoirs in this stream with the solid taking up the lighter Zn isotope. The preference of the lighter isotope in the solid reservoir may reflect metabolic uptake of Zn by microorganisms. Additional field investigations must evaluate the contributions of soils, rocks, minerals, and anthropogenic components to Cu and Zn isotopic fluxes in natural waters. Moreover, rigorous experimental work is necessary to quantify fractionation factors for the biogeochemical reactions that are likely to impact Cu and Zn isotopes in hydrologic systems. This initial investigation of Cu and Zn isotopes in stream waters suggests that these isotopes may be powerful tools for probing biogeochemical processes in surface waters on a variety of temporal and spatial scales.

Aided phytoextraction of Cu, Pb, Zn, and As in copper-contaminated soils with tobacco and sunflower in crop rotation: Mobility and phytoavailability assessment.

PubMed

Hattab-Hambli, Nour; Motelica-Heino, Mikael; Mench, Michel

2016-02-01

Copper-contaminated soils were managed with aided phytoextraction in 31 field plots at a former wood preservation site, using a single incorporation of compost (OM) and dolomitic limestone (DL) followed by a crop rotation with tobacco and sunflower. Six amended plots, with increasing total soil Cu, and one unamended plot were selected together with a control uncontaminated plot. The mobility and phytoavailability of Cu, Zn, Cr and As were investigated after 2 and 3 years in soil samples collected in these eight plots. Total Cu, Zn, Cr and As concentrations were determined in the soil pore water (SPW) and available soil Cu and Zn fractions by DGT. The Cu, Zn, Cr and As phytoavailability was characterized by growing dwarf beans on potted soils and determining the biomass of their plant parts and their foliar ionome. Total Cu concentrations in the SPW increased with total soil Cu. Total Cu, Zn, Cr and As concentrations in the SPW decreased in year 3 as compared to year 2, likely due to annual shoot removals by the plants and the lixiviation. Available soil Cu and Zn fractions also declined in year 3. The Cu, Zn, Cr and As phytoavailability, assessed by their concentration and mineral mass in the primary leaves of beans, was reduced in year 3. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preparation, structural, photoluminescence and magnetic studies of Cu doped ZnO nanoparticles co-doped with Ni by sol-gel method

NASA Astrophysics Data System (ADS)

Theyvaraju, D.; Muthukumaran, S.

2015-11-01

Zn0.96-xNi0.04CuxO nanoparticles have been synthesized by varying different Cu concentrations between 0% and 4% using simple sol-gel method. X-ray diffraction studies confirmed the hexagonal structure of the prepared samples. The formation of secondary phases, CuO (111) and Zn (101) at higher Cu content is due un-reacted Cu2+ and Zn2+ ions present in the solution which reduces the interaction between precursor ions and surfaces of ZnO. Well agglomerated and rod-like structure noticed at Cu=4% greatly de-generate and enhanced the particle size. The nominal elemental composition of Zn, Cu, Ni and O was confirmed by energy dispersive X-ray analysis. Even though energy gap was increased (blue-shift) from Cu=0-2% by quantum size effect, the s-d and p-d exchange interactions between the band electrons of ZnO and localized d electrons of Cu and Ni led to decrease (red-shift) the energy gap at Cu=4%. Presence of Zn-Ni-Cu-O bond was confirmed by Fourier transform infrared analysis. Ultraviolet emission by band to band electronic transition and defect related blue emission were discussed by photoluminescence spectra. The observed optical properties concluded that the doping of Cu in the present system is useful to tune the emission wavelength and hence acting as the important candidates for the optoelectronic device applications. Ferromagnetic ordering of Cu=2% sample was enhanced by charge carrier concentration where as the antiferromagnetic interaction between neighboring Cu-Cu ions suppressed the ferromagnetism at higher doping concentrations of Cu.

Theory of copper impurities in ZnO

NASA Astrophysics Data System (ADS)

Lyons, John; Alkauskas, Audrius; Janotti, Anderson; van de Walle, Chris G.

Due to its connection to deep luminescence signals and its potential use as an acceptor dopant, copper has been one the most studied impurities in ZnO. From experiment, copper incorporating on the Zn site (CuZn) is known to lead to an acceptor level residing near the conduction band of ZnO, making CuZn an exceedingly deep acceptor. CuZn in ZnO has also long been linked with broad 2.4 eV green luminescence (GL) signals. In this work we explore the electrical and optical properties of Cu in ZnO using density functional theory (DFT). Due to the limitations of traditional forms of DFT, an accurate theoretical description of the electrical and optical properties of such deep centers has been difficult to achieve. Here we employ a screened hybrid density functional (HSE) to calculate the properties of Cu in ZnO. We determine the thermodynamic transition levels associated with CuZn in ZnO as well as the associated luminescence lineshapes of characteristic optical transitions. We find that HSE-calculated optical transitions are in close agreement with experimental studies. This work was supported in part by NSF and by ARO.

The effect of Ti-B on stabilization of Cu-Zn-Al martensite

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

Stipcich, M.; Romero, R.

1998-10-05

The application of shape memory effect in devices requires, in many cases, stable and reliable transformation temperatures. However, as a consequence of diffusional processes, in Cu-based shape memory alloys, reverse transformation temperature significantly rises after aging at temperatures above room temperature. This generally unwanted behavior is usually referred to as the stabilization of martensite. Numerous investigations have been carried out on this subject as reviewed by Ahlers and Chandrasekaran et al. Within the Cu-based alloys the Cu-Zn-Al are claimed to be more prone to stabilization than Cu-Al-Ni on aging. It has been proposed that in the Cu-Zn-Al the stabilization ismore » due to the interchange of Cu and Zn atoms assisted by vacancies, changing, consequently, the long range order inherited from the {beta} phase. In the present work, the authors investigate the stabilization behavior of polycrystalline samples of stress induced Cu-Zn-Al and Cu-Zn-Al-B martensite.« less

A Stable Plasmonic Cu@Cu2 O/ZnO Heterojunction for Enhanced Photocatalytic Hydrogen Generation.

PubMed

Lou, Yongbing; Zhang, Yake; Cheng, Lin; Chen, Jinxi; Zhao, Yixin

2018-05-09

The localized surface plasmon resonance (LSPR) effect has been widely utilized in photocatalysis, but most reported LSPR materials are based on noble metals of gold or silver with high chemical stability. Plasmonic copper nanoparticles that exhibit an LSPR absorbance at 600 nm are promising for many applications, such as photocatalysis. Unfortunately, plasmonic copper nanoparticles are affected by serious surface oxidation in air. Herein, a novel lollipop-shaped Cu@Cu 2 O/ZnO heterojunction nanostructure was designed, for the first time, to stabilize the plasmonic Cu core by decorating Cu@Cu 2 O core-shell structures with ZnO nanorods. This Cu@Cu 2 O/ZnO nanostructure exhibited significantly enhanced stability than that of regular Cu@Cu 2 O, which accounted for the remarkably enhanced photocatalytic H 2 evolution rate through water splitting, relative to pristine ZnO nanorods, over an extended wavelength range due to the plasmonic Cu core. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Superoxide and Singlet Oxygen Produced within the Thylakoid Membranes Both Cause Photosystem I Photoinhibition.

PubMed

Takagi, Daisuke; Takumi, Shigeo; Hashiguchi, Masaki; Sejima, Takehiro; Miyake, Chikahiro

2016-07-01

Photosystem I (PSI) photoinhibition suppresses plant photosynthesis and growth. However, the mechanism underlying PSI photoinhibition has not been fully clarified. In this study, in order to investigate the mechanism of PSI photoinhibition in higher plants, we applied repetitive short-pulse (rSP) illumination, which causes PSI-specific photoinhibition in chloroplasts isolated from spinach leaves. We found that rSP treatment caused PSI photoinhibition, but not PSII photoinhibition in isolated chloroplasts in the presence of O2 However, chloroplastic superoxide dismutase and ascorbate peroxidase activities failed to protect PSI from its photoinhibition. Importantly, PSI photoinhibition was largely alleviated in the presence of methyl viologen, which stimulates the production of reactive oxygen species (ROS) at the stromal region by accepting electrons from PSI, even under the conditions where CuZn-superoxide dismutase and ascorbate peroxidase activities were inactivated by KCN. These results suggest that the ROS production site, but not the ROS production rate, is critical for PSI photoinhibition. Furthermore, we found that not only superoxide (O2 (-)) but also singlet oxygen ((1)O2) is involved in PSI photoinhibition induced by rSP treatment. From these results, we suggest that PSI photoinhibition is caused by both O2 (-) and (1)O2 produced within the thylakoid membranes when electron carriers in PSI become highly reduced. Here, we show, to our knowledge, new insight into the PSI photoinhibition in higher plants. © 2016 American Society of Plant Biologists. All Rights Reserved.

Improved sensitivity of polychlorinated-biphenyl-orientated porous-ZnO surface photovoltage sensors from chemisorption-formed ZnO-CuPc composites

PubMed Central

Li, Mingtao; Meng, Guowen; Huang, Qing; Zhang, Shile

2014-01-01

We report a new mechanism for the enhancement of porous-ZnO surface photovoltage (SPV) response to polychlorinated biphenyls (PCBs, a notorious class of persistent organic pollutants as global environmental hazard) based on copper phthalocyanine (CuPc) chemisorptive bonding on porous-ZnO. A new ZnO-CuPc composite is formed on the porous-ZnO surface due to the interaction between the surface ZnO and CuPc, with its valence band (VB) energy level being higher than that of the pristine porous-ZnO. So that the efficiency of the photogenerated-electron transfer from the composite VB to the adjacent ZnO's surface states is drastically increased due to the reduced energy gap between the transition states. As a result, the sensitivity of the PCB-orientated SPV sensor is much improved by showing amplified variation of the SPV-signals perturbed by PCBs adsorbed on the ZnO-CuPc@porous-ZnO sensitive material. PMID:24594662

A New Test of Copper and Zinc Abundances in Late-Type Stars Using Cu II and Zn II lines in the Near-Ultraviolet

NASA Astrophysics Data System (ADS)

Roederer, Ian

2017-08-01

The copper (Cu, Z = 29) and zinc (Zn, Z = 30) abundances found in late-type stars provide critical constraints on models that predict the yields of massive star supernovae, hypernovae, Type Ia supernovae, and AGB stars, which are essential ingredients in Galactic chemical evolution models. Furthermore, Zn is commonly used to compare the abundance of iron-group elements in the gas phase in high-redshift DLA systems with metallicities in Local Group stars. It is thus important that the observational Cu and Zn abundances in stars are correct. My proposed archive study will address this issue by using archive STIS spectra of 14 stars to provide the first systematic observational tests of non-LTE calculations of Cu and Zn line formation in late-type stars. The non-LTE calculations predict that all LTE [Cu/Fe] abundance ratios presently found in the literature are systematically lower than the true ratios found in stars. The non-LTE calculations for Zn predict that the LTE values in the literature may be systematically overestimated in low-metallicity stars. The LTE abundances of Cu and Zn are derived from Cu I and Zn I lines. The key advance enabled by the use of NUV spectra is the detection of several lines of Cu II and Zn II, which cannot be detected in the optical or infrared. Cu II and Zn II are largely immune to non-LTE effects in the atmospheres of late-type stars. The metallicities of the 14 stars with NUV spectra span -2.6 < [Fe/H] < -0.1, which covers the range of most Cu and Zn abundances reported in the literature. The proposed study will allow me to test the non-LTE calculations and calibrate the stellar abundances.

Copper Ion from Cu2O Crystal Induces AMPK-Mediated Autophagy via Superoxide in Endothelial Cells

PubMed Central

Seo, Youngsik; Cho, Young-Sik; Huh, Young-Duk; Park, Heonyong

2016-01-01

Copper is an essential element required for a variety of functions exerted by cuproproteins. An alteration of the copper level is associated with multiple pathological conditions including chronic ischemia, atherosclerosis and cancers. Therefore, copper homeostasis, maintained by a combination of two copper ions (Cu+ and Cu2+), is critical for health. However, less is known about which of the two copper ions is more toxic or functional in endothelial cells. Cubic-shaped Cu2O and CuO crystals were prepared to test the role of the two different ions, Cu+ and Cu2+, respectively. The Cu2O crystal was found to have an effect on cell death in endothelial cells whereas CuO had no effect. The Cu2O crystals appeared to induce p62 degradation, LC3 processing and an elevation of LC3 puncta, important processes for autophagy, but had no effect on apoptosis and necrosis. Cu2O crystals promote endothelial cell death via autophagy, elevate the level of reactive oxygen species such as superoxide and nitric oxide, and subsequently activate AMP-activated protein kinase (AMPK) through superoxide rather than nitric oxide. Consistently, the AMPK inhibitor Compound C was found to inhibit Cu2O-induced AMPK activation, p62 degradation, and LC3 processing. This study provides insight on the pathophysiologic function of Cu+ ions in the vascular system, where Cu+ induces autophagy while Cu2+ has no detected effect. PMID:26743904

Influence of Li Addition to Zn-Al Alloys on Cu Substrate During Spreading Test and After Aging Treatment

NASA Astrophysics Data System (ADS)

Gancarz, Tomasz; Pstrus, Janusz; Cempura, Grzegorz; Berent, Katarzyna

2016-12-01

The spreading of Zn-Al eutectic-based alloys with 0.05 wt.%, 0.1 wt.%, and 0.2 wt.% Li on Cu substrate has been studied using the sessile drop method in presence of QJ201 flux. Wetting tests were performed after 1 min, 3 min, 8 min, 15 min, 30 min, and 60 min of contact at temperatures of 475°C, 500°C, 525°C, and 550°C. Samples after spreading at 500°C for 1 min were subjected to aging for 1 day, 10 days, and 30 days at temperature of 120°C, 170°C, and 250°C. The spreadability of eutectic Zn-5.3Al alloy with different Li contents on Cu substrate was determined in accordance with ISO 9455-10:2013-03. Selected solidified solder-substrate couples were, after spreading and aging tests, cross-sectioned and subjected to scanning electron microscopy, energy-dispersive spectroscopy (EDS), and x-ray diffraction (XRD) analysis of the interfacial microstructure. An experiment was designed to demonstrate the effect of Li addition on the kinetics of the formation and growth of CuZn, Cu5Zn8, and CuZn4 intermetallic compound (IMC) phases, during spreading and aging. The IMC layers formed at the interface were identified using XRD and EDS analyses. Increasing addition of Li to Zn-Al alloy caused a reduction in the thickness of the IMC layer at the interface during spreading, and an increase during aging. The activation energy was calculated, being found to increase for the Cu5Zn8 phase but decrease for the CuZn and CuZn4 phases with increasing Li content in the Zn-Al-Li alloys. The highest value of 142 kJ mol-1 was obtained for Zn-Al with 1.0 Li during spreading and 69.2 kJ mol-1 for Zn-Al with 0.05 Li during aging. Aging at 250°C caused an increase in only the Cu5Zn8 layer, which has the lowest Gibbs energy in the Cu-Zn system. This result is connected to the high diffusion of Cu from the substrate to the solder.

Effect of the transit through the gut of earthworm (Eisenia fetida) on fractionation of Cu and Zn in pig manure.

PubMed

Li, Lingxiangyu; Wu, Jianyang; Tian, Guangming; Xu, Zhenlan

2009-08-15

To investigate the effect of the transit through the gut of earthworm (Eisenia fetida) on the fractionation of Cu and Zn in pig manure, earthworms were reared with pig manure in the greenhouse. Both the pig manure and the earthworm casts were subjected to a five-step sequential extraction of Cu and Zn. The content of Cu bound to organic matter in pig manure increased from 60% to 75% after transit through the gut of earthworm, whereas that of Zn decreased from 50% to 25%. It demonstrated that Cu had a strong affinity towards organic matter. The share of Cu and Zn in the exchangeable fraction was reduced by the transit through the gut of earthworm. Based on these changes, Cu was more bioavailable, whereas Zn was less bioavailable. The factors affecting metal fractionation, like pH, organic matter (OM) and total phosphorous (TP) contents, and total metal concentration, were also affected significantly by the transit through the gut of earthworm. Stepwise multiple regression analysis revealed that the fractionation of Cu in the earthworm casts was influenced by OM, TP and the amount of Cu in the earthworm casts. The total Zn concentration in the earthworm casts was the primary factor that explained most of the variation in Zn fractionation. The present study demonstrated that the digestive activity in the gut of E. fetida played an important role in the fraction redistribution of Cu and Zn in pig manure.

Biomarkers of Oxidative Stress and Heavy Metal Levels as Indicators of Environmental Pollution in African Cat Fish (Clarias gariepinus) from Nigeria Ogun River

PubMed Central

Farombi, E. O.; Adelowo, O. A.; Ajimoko, Y. R.

2007-01-01

Levels of Zn, Cu, Cd, As, and Pb in the kidney, Liver, Gills and Heart of African cat fish (Clarias gariepinus) from the Ogun River in Ogun State located close to six major industries in the South Western part of Nigeria, were determined using Bulk Scientific Atomic Absorption Spectrophotometer. Fishes were also collected from Government owned fish farm in Agodi, Ibadan which was considered a reference site. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione S-transferase (GST), glutathione (GSH) concentration and malondialdehyde (MDA) formation were also determined. The trend of accumulation of the metals in the organs is as follows: Heart - Zn > Cu > Pb > As > Cd; Gills - Zn > Cu > Pb > Cd > As; Kidney - Zn > Cu > Pb > As > Cd; Liver -Zn > Cu > Pb > As > Cd. The order of concentration of the metals in the organs is as follows: Arsenite - Kidney > Liver > Gills > Heart; Zinc - Gills > Liver > Kidney > Heart; Lead- Liver > Kidney > Gills > Heart; Copper- Kidney > Liver > Gills > Heart; Cadmium > Liver > Gills > Kidney > Heart. The levels of heavy metals ranged between 0.25–8.96 ppm in the heart, 0.69– 19.05 ppm in the kidneys, 2.10–19.75 ppm in the liver and 1.95–20.35 ppm in the gills. SOD activity increased by 61% in the liver, 50% in the kidney and in the heart by 28 % while a significant decrease (44%) was observed in the gill of Clarias gariepinus from Ogun river compared to that Agodi fish farm (P<0.001). On the contrary there was 46%, 41%, 50% and 19% decrease in CAT activity in the liver, kidney, gills and heart respectively. The levels of GST activities in the liver, kidney and heart of Clarias gariepinus from Ogun river increased by 62%, 72% and 37% respectively (P<0.001) whereas there was a significant decrease (41%) in the gills (P<0.05) compared to that from the Agodi fish farm. GSH concentration increased by 81%, 83% and 53% in the liver, kidney and heart respectively but decreased by 44% in the gills. MDA levels of Clarias gariepinus were significantly (P<0.001) elevated in the liver, kidney, gills and heart by 177%, 102%, 168% and 71% respectively compared to that from Agodi fish farm. Overall, the results demonstrate that alteration in the antioxidant enzymes, glutathione system and induction of lipid peroxidation reflects the presence of heavy metals which may cause oxidative stress in the Clarias gariepinus from Ogun River. The study therefore provides a rational use of biomarkers of oxidative stress in biomonitoring of aquatic pollution. PMID:17617680

Reduced anti-ferromagnetism promoted by Zn 3d 10 substitution at CuO 2 planar sites of Cu 0.5Tl 0.5Ba 2Ca 3Cu 4O 12-δ superconductors

NASA Astrophysics Data System (ADS)

Mumtaz, M.; Khan, Nawazish A.

2009-11-01

The role of charge carriers in ZnO 2/CuO 2 planes of Cu 0.5Tl 0.5Ba 2Ca 3Cu 4-yZn yO 12-δ material in bringing about superconductivity has been explained. Due to suppression of anti-ferromagnetic order with Zn 3d 10 ( S=0) substitution at Cu 3d 9(S={1}/{2}) sites in the inner CuO 2 planes of Cu 0.5Tl 0.5Ba 2Ca 3Cu 4O 12-δ superconductor, the distribution of charge carriers becomes homogeneous and optimum, which is evident from the enhanced superconductivity parameters. The decreased c-axis length with the increase of Zn doping improves interlayer coupling and hence the three dimensional (3D) conductivity in the unit cell is enhanced. Also the softening of phonon modes with the increased Zn doping indicates that the electron-phonon interaction has an essential role in the mechanism of high- Tc superconductivity in these compounds.

Oxidative Stress Induced Age Dependent Meibomian Gland Dysfunction in Cu, Zn-Superoxide Dismutase-1 (Sod1) Knockout Mice

PubMed Central

Ibrahim, Osama M. A.; Dogru, Murat; Matsumoto, Yukihiro; Igarashi, Ayako; Kojima, Takashi; Wakamatsu, Tais Hitomi; Inaba, Takaaki; Shimizu, Takahiko; Shimazaki, Jun; Tsubota, Kazuo

2014-01-01

Purpose The purpose of our study was to investigate alterations in the meibomian gland (MG) in Cu, Zn-Superoxide Dismutase-1 knockout (Sod1 −/−) mouse. Methods Tear function tests [Break up time (BUT) and cotton thread] and ocular vital staining test were performed on Sod1 −/− male mice (n = 24) aged 10 and 50 weeks, and age and sex matched wild–type (+/+) mice (n = 25). Tear and serum samples were collected at sacrifice for inflammatory cytokine assays. MG specimens underwent Hematoxylin and Eosin staining, Mallory staining for fibrosis, Oil Red O lipid staining, TUNEL staining, immunohistochemistry stainings for 4HNE, 8-OHdG and CD45. Transmission electron microscopic examination (TEM) was also performed. Results Corneal vital staining scores in the Sod1 −/− mice were significantly higher compared with the wild type mice throughout the follow-up. Tear and serum IL-6 and TNF-α levels also showed significant elevations in the 10 to 50 week Sod1 −/− mice. Oil Red O staining showed an accumulation of large lipid droplets in the Sod1 −/− mice at 50 weeks. Immunohistochemistry revealed both increased TUNEL and oxidative stress marker stainings of the MG acinar epithelium in the Sod1 −/− mice compared to the wild type mice. Immunohistochemistry staining for CD45 showed increasing inflammatory cell infiltrates from 10 to 50 weeks in the Sod1 −/− mice compared to the wild type mice. TEM revealed prominent mitochondrial changes in 50 week Sod1 −/− mice. Conclusions Our results suggest that reactive oxygen species might play a vital role in the pathogensis of meibomian gland dysfunction. The Sod1 −/− mouse appears to be a promising model for the study of reactive oxygen species associated MG alterations. PMID:25036096

Pyrimethamine significantly lowers cerebrospinal fluid Cu/Zn superoxide dismutase in amyotrophic lateral sclerosis patients with SOD1 mutations.

PubMed

Lange, Dale J; Shahbazi, Mona; Silani, Vincenzo; Ludolph, Albert C; Weishaupt, Jochen H; Ajroud-Driss, Senda; Fields, Kara G; Remanan, Rahul; Appel, Stanley H; Morelli, Claudia; Doretti, Alberto; Maderna, Luca; Messina, Stefano; Weiland, Ulrike; Marklund, Stefan L; Andersen, Peter M

2017-06-01

Cu/Zn superoxide dismutase (SOD1) reduction prolongs survival in SOD1-transgenic animal models. Pyrimethamine produces dose-dependent SOD1 reduction in cell culture systems. A previous phase 1 trial showed pyrimethamine lowers SOD1 levels in leukocytes in patients with SOD1 mutations. This study investigated whether pyrimethamine lowered SOD1 levels in the cerebrospinal fluid (CSF) in patients carrying SOD1 mutations linked to familial amyotrophic lateral sclerosis (fALS/SOD1). A multicenter (5 sites), open-label, 9-month-duration, dose-ranging study was undertaken to determine the safety and efficacy of pyrimethamine to lower SOD1 levels in the CSF in fALS/SOD1. All participants underwent 3 lumbar punctures, blood draw, clinical assessment of strength, motor function, quality of life, and adverse effect assessments. SOD1 levels were measured in erythrocytes and CSF. Pyrimethamine was measured in plasma and CSF. Appel ALS score, ALS Functional Rating Scale-Revised, and McGill Quality of Life Single-Item Scale were measured at screening, visit 6, and visit 9. We enrolled 32 patients; 24 completed 6 visits (18 weeks), and 21 completed all study visits. A linear mixed effects model showed a significant reduction in CSF SOD1 at visit 6 (p < 0.001) with a mean reduction of 13.5% (95% confidence interval [CI] = 8.4-18.5) and at visit 9 (p < 0.001) with a mean reduction of 10.5% (95% CI = 5.2-15.8). Pyrimethamine is safe and well tolerated in ALS. Pyrimethamine is capable of producing a significant reduction in total CSF SOD1 protein content in patients with ALS caused by different SOD1 mutations. Further long-term studies are warranted to assess clinical efficacy. Ann Neurol 2017;81:837-848. © 2017 The Authors. Annals of Neurology published by Wiley Periodicals, Inc. on behalf of American Neurological Association.

Methane alleviates copper-induced seed germination inhibition and oxidative stress in Medicago sativa.

PubMed

Samma, Muhammad Kaleem; Zhou, Heng; Cui, Weiti; Zhu, Kaikai; Zhang, Jing; Shen, Wenbiao

2017-02-01

Recent results discovered the protective roles of methane (CH 4 ) against oxidative stress in animals. However, the possible physiological roles of CH 4 in plants are still unknown. By using physiological, histochemical and molecular approaches, the beneficial role of CH 4 in germinating alfalfa seeds upon copper (Cu) stress was evaluated. Endogenous production of CH 4 was significantly increased in Cu-stressed alfalfa seeds, which was mimicked by 0.39 mM CH 4 . The pretreatment with CH 4 significantly alleviated the inhibition of seed germination and seedling growth induced by Cu stress. Cu accumulation was obviously blocked as well. Meanwhile, α/β amylase activities and sugar contents were increased, all of which were consistent with the alleviation of seed germination inhibition triggered by CH 4 . The Cu-triggered oxidative stress was also mitigated, which was confirmed by the decrease of lipid peroxidation and reduction of Cu-induced loss of plasma membrane integrity in CH 4 -pretreated alfalfa seedlings. The results of antioxidant enzymes, including ascorbate peroxidase (APX), superoxide dismutase (SOD), catalase (CAT), and guaiacol peroxidase (POD) total or isozymatic activities, and corresponding transcripts (APX1/2, Cu/Zn SOD and Mn-SOD), indicated that CH 4 reestablished cellular redox homeostasis. Further, Cu-induced proline accumulation was partly impaired by CH 4 , which was supported by the alternation of proline metabolism. Together, these results indicated that CH 4 performs an advantageous effect on the alleviation of seed germination inhibition caused by Cu stress, and reestablishment of redox homeostasis mainly via increasing antioxidant defence.

Synergies between Unsaturated Zn/Cu Doping Sites in Carbon Dots Provide New Pathways for Photocatalytic Oxidation

DOE PAGES

Wu, Wenting; Zhang, Qinggang; Wang, Ruiqin; ...

2017-12-07

Unsaturated metal species (UMS) confined in nanomaterials play important roles for electron transfer in a wide range of catalytic reactions. However, the limited fabrication methods of UMS restrict their wider catalytic applications. Here in this paper, we report on the synergy of unsaturated Zn and Cu dopants confined in carbon dots (ZnCu-CDs) to produce enhanced electron transfer and photooxidation processes in the doped CDs. The Zn/Cu species chelate with the carbon matrix mainly through Cu-O(N)-Zn-O(N)-Cu complexes. Within this structure, Cu 2+ acts as a mild oxidizer that facilely increases the unsaturated Zn content and also precisely tunes the unsaturated Znmore » valence state to Zn d+, where d is between 1 and 2, instead of Zn. With the help of UMS, electron-transfer pathways are produced, enhancing both the electron donating (7.0 times) and-accepting (5.3 times) abilities relative to conventional CDs. Because of these synergistic effects, the photocatalytic efficiency of CDs in photooxidation reactions is shown to improve more than 5-fold.« less

Potential effect of CuInS2/ZnS core-shell quantum dots on P3HT/PEDOT:PSS heterostructure based solar cell

NASA Astrophysics Data System (ADS)

Jindal, Shikha; Giripunje, S. M.

2018-07-01

Nanostructured quantum dots (QDs) are quite promising in the solar cell application due to quantum confinement effect. QDs possess multiple exciton generation and large surface area. The environment friendly CuInS2/ZnS core-shell QDs were prepared by solvothermal method. Thus, the 3 nm average sized CuInS2/ZnS QDs were employed in the bulk heterojunction device and the active blend layer consisting of the P3HT and CuInS2/ZnS QDs was investigated. The energy level information of CuInS2/ZnS QDs as an electron acceptor was explored by ultra violet photoelectron spectroscopy. Bulk heterojunction hybrid device of ITO/PEDOT:PSS/P3HT: (CuInS2/ZnS QDs)/ZnO/Ag was designed by spin coating approach and its electrical characterization was investigated by solar simulator. Current density - voltage characteristics shows the enhancement in power conversion efficiency with increasing concentration of CuInS2/ZnS QDs in bulk heterojunction device.

Comparison of Cu2+ and Zn2+ thermalcatalyst in treating diazo dye

NASA Astrophysics Data System (ADS)

Lau, Y. Y.; Wong, Y. S.; Ong, S. A.; Lutpi, N. A.; Ho, L. N.

2018-05-01

This research demonstrates the comparison between copper (II) sulphate (CuSO4) and zinc oxide (ZnO) as thermalcatalysts in thermolysis process for the treatment of diazo reactive black 5 (RB 5) wastewater. CuSO4 was found to be the most effective thermalcatalyst in comparison to ZnO. The color removal efficiency of RB 5 catalysed by CuSO4 and ZnO were 91.55 % at pH 9.5 and 7.36 % at pH 2, respectively. From the UV-Vis wavelength scan, CuSO4 catalyst is able to cleave the molecular structure bonding more efficiently compared to ZnO. ZnO which only show a slight decay on the main chemical network strands: azo bond, naphthalene and benzene rings whereas CuSO4 catalyst is able to fragment azo bond and naphthalene more effectively. The degradation reactions of CuSO4 and ZnO as thermalcatalysts in thermolysis process were compared.

Toxicity of nanoparticles of CuO, ZnO and TiO2 to microalgae Pseudokirchneriella subcapitata.

PubMed

Aruoja, Villem; Dubourguier, Henri-Charles; Kasemets, Kaja; Kahru, Anne

2009-02-01

Toxicities of ZnO, TiO2 and CuO nanoparticles to Pseudokirchneriella subcapitata were determined using OECD 201 algal growth inhibition test taking in account potential shading of light. The results showed that the shading effect by nanoparticles was negligible. ZnO nanoparticles were most toxic followed by nano CuO and nano TiO2. The toxicities of bulk and nano ZnO particles were both similar to that of ZnSO4 (72 h EC50 approximately 0.04 mg Zn/l). Thus, in this low concentration range the toxicity was attributed solely to solubilized Zn2+ ions. Bulk TiO2 (EC50=35.9 mg Ti/l) and bulk CuO (EC50=11.55 mg Cu/l) were less toxic than their nano formulations (EC50=5.83 mg Ti/l and 0.71 mg Cu/l). NOEC (no-observed-effect-concentrations) that may be used for risk assessment purposes for bulk and nano ZnO did not differ (approximately 0.02 mg Zn/l). NOEC for nano CuO was 0.42 mg Cu/l and for bulk CuO 8.03 mg Cu/l. For nano TiO2 the NOEC was 0.98 mg Ti/l and for bulk TiO2 10.1 mg Ti/l. Nano TiO2 formed characteristic aggregates entrapping algal cells that may contribute to the toxic effect of nano TiO2 to algae. At 72 h EC50 values of nano CuO and CuO, 25% of copper from nano CuO was bioavailable and only 0.18% of copper from bulk CuO. Thus, according to recombinant bacterial and yeast Cu-sensors, copper from nano CuO was 141-fold more bioavailable than from bulk CuO. Also, toxic effects of Cu oxides to algae were due to bioavailable copper ions. To our knowledge, this is one of the first systematic studies on effects of metal oxide nanoparticles on algal growth and the first describing toxic effects of nano CuO towards algae.

Evidences for Cu and Zn Isotope Fractionation in Sediments and Particulate Suspended Matter of the Scheldt Estuary

NASA Astrophysics Data System (ADS)

Petit, J.; Mattielli, N.; de Jong, J.; Chou, L.

2004-05-01

Recent developments in MC-ICP-MS technology allow high precision measurements of heavy stable isotopes, such as Cu and Zn isotopes, which have been shown to undergo biotic or abiotic fractionation (1). Application of Zn isotopes to the study of aquatic ecosystems has already shown some interesting perspectives in their potential use as biogeochemical tracers in deep ocean carbonates (2) or Fe-Mn nodules (3). However, until now no investigation of possible Cu and Zn isotopic fractionation has been carried out within estuaries that are important pathways for hydrological and geochemical cycling of metals. Cu and Zn isotope geochemistry has been studied in sandy to loamy surface sediments (top 20 cm) and in suspended particulate matter (SPM) along a transect in a strong tidal estuary, the Scheldt estuary situated in Belgium and the Netherlands (November 2002). Further to separation of Cu, Fe and Zn by one step ion-exchange chromatography, Cu and Zn isotopic ratios are measured with a "Nu-Plasma" MC-ICP-MS. Instrumental mass bias is corrected using reference materials (Zn JMC, Cu NIST SRM 976 and Ga JMC standard) by simultaneous standard-sample bracketing and external normalization (500 ppb Zn doping for Cu isotopic analyses in static mode and 250 ppb Ga doping for Zn isotopic analyses in dynamic mode), together with a Ni correction. These methods lead to long-term reproducibility (2σ at 95 % confidence level) of ± 0.07 per mil for δ 66Zn (n=100 over 7 analysis sessions) and ± 0.06 per mil for δ 65Cu (n=120 over 8 analysis sessions) for 500 ppb of reference material. Average beam intensities are 6 V/ppm. Precise and reproducible results are obtained for concentration as low as 100 ppb for Cu and Zn. Expected Cu and Zn enrichment in SPM (120 ppm and 1200 ppm respectively) and sediments (being 6 to 10 times lower than SPM) in the upper estuary and progressive decrease in metal content by mixing downstream of the maximum turbidity zone (MTZ, around 5 psu) are observed. Results show that variations in Cu and Zn isotopic composition are smaller in SPM (δ 66Zn varying from 0.35 to 0.17 and δ 65Cu from -0.13 to 0.18) than in sediments. Cu and Zn isotopic signatures of sediments show a clear trend of lighter isotopes removal from the MTZ seaward with δ 66Zn varying from 0.21 at 2 psu to 1.11 per mil at 33 psu (and δ 65Cu = -0.37 to 0.24). In contrast, Zn isotopic compositions in SPM are more homogeneous with average δ 66Zn of 0.24 ± 0.18 over all the transect. Cu isotopic composition in SPM are very constant downstream of the MTZ with average δ 65Cu =-0.06 ± 0.08 but become more scattered within MTZ (varying from -0.04 to 0.18). These preliminary results pinpoint important variations in Cu and Zn isotopic compositions within estuarine systems and contrasted isotopic signatures in Cu and Zn between SPM and sediments. Results suggest the important role of early diagenesis in the isotope geochemistry of heavy metals in estuarine environment. This study provides a stepping stone for further investigation of interacting processes involved in controlling the cycling of metals in the Scheldt estuary. (1) Zhu et al., Earth Planet. Sci. Lett. 200 (2002), 47-62 (2) Pichat et al., Earth Planet. Sci. Lett. 6598 (2003), 1-12 (3) Maréchal et al., Geochem. Geophys. Geosyt., 1 (2000), GC000029

Fe{sub 3}O{sub 4}/CuO/ZnO/Nano graphene platelets (Fe{sub 3}O{sub 4}/CuO/ZnO/NGP) composites prepared by sol-gel method with enhanced sonocatalytic activity for the removal of dye

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

Hendry, Tju; Taufik, Ardiansyah; Saleh, Rosari, E-mail: rosari.saleh@gmail.com, E-mail: rosari.saleh@ui.ac.id

2016-04-19

In this study, an attempt has been made to synthesize nanographene platelets coupled with Fe3O4/CuO/ZnO (Fe3O4/CuO/ZnO/NGP) with various ZnO loadings using a two step methods, sol-gel followed by hydrothermal method. Characterization was carried out by X-ray diffraction, energy-dispersive X-ray spectroscopy and vibrating sample magnetometer. The sonocatalytic performance was evaluated by degradation of methylene blue under ultrasonic irradiation.The Fe3O4/CuO/ZnO/NGP showed superior sonocatalytic activity than the Fe3O4/CuO/ZnO materials. They also showed high stability and can be easily separated from the reaction system for recycling process.

Electronic absorption band broadening and surface roughening of phthalocyanine double layers by saturated solvent vapor treatment

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

Kim, Jinhyun; Yim, Sanggyu, E-mail: sgyim@kookmin.ac.kr

2012-10-15

Variations in the electronic absorption (EA) and surface morphology of three types of phthalocyanine (Pc) thin film systems, i.e. copper phthalocyanine (CuPc) single layer, zinc phthalocyanine (ZnPc) single layer, and ZnPc on CuPc (CuPc/ZnPc) double layer film, treated with saturated acetone vapor were investigated. For the treated CuPc single layer film, the surface roughness slightly increased and bundles of nanorods were formed, while the EA varied little. In contrast, for the ZnPc single layer film, the relatively high solubility of ZnPc led to a considerable shift in the absorption bands as well as a large increase in the surface roughnessmore » and formation of long and wide nano-beams, indicating a part of the ZnPc molecules dissolved in acetone, which altered their molecular stacking. For the CuPc/ZnPc film, the saturated acetone vapor treatment resulted in morphological changes in mainly the upper ZnPc layer due to the significantly low solubility of the underlying CuPc layer. The treatment also broadened the EA band, which involved a combination of unchanged CuPc and changed ZnPc absorption.« less

In Situ Subcellular Imaging of Copper and Zinc in Contaminated Oysters Revealed by Nanoscale Secondary Ion Mass Spectrometry.

PubMed

Weng, Nanyan; Jiang, Haibo; Wang, Wen-Xiong

2017-12-19

Determining the in situ localization of trace elements at high lateral resolution levels in the biological system is very challenging, but critical for our understanding of metal sequestration and detoxification. Here, the cellular and subcellular distributions of Cu and Zn in contaminated oysters of Crassostrea hongkongensis were for the first time mapped using nanoscale secondary ion mass spectrometry (nanoSIMS). Three types of metal-containing cells were revealed in the gill and mantle of oysters, including Cu-specific hemocytes, Cu and Zn-containing granular hemocytes, and Cu and Zn-containing calcium cells. Obvious intercellular distribution of Cu was found in the gill tissue, indicating the potential role of hemolymph in the transportation of Cu in oysters. The distribution of Cu showed a strong colocalization with sulfur and nitrogen in Cu-specific hemocyte and intercellular hemolymph. In the Cu and Zn-containing granular hemocytes and calcium cells, the co-occurrence of Cu and Zn with phosphorus and calcium was also found. Different relationships of distributions between Cu/Zn and macronutrient elements (nitrogen, sulfur and phosphorus) implied the differential metal complexation in oysters. Interestingly, quantitative analysis of the ratios of 32 S - / 12 C 14 N - and 31 P - / 12 C 14 N - of metal-deposited sites suggested the dynamic process of transfer of Cu and Zn from the metabolized protein pool to a more thermodynamically stable and detoxified form.

Facile synthesis and photocatalytic activity of bi-phase dispersible Cu-ZnO hybrid nanoparticles

NASA Astrophysics Data System (ADS)

Liu, Xiao; Liu, HongLing; Zhang, WenXing; Li, XueMei; Fang, Ning; Wang, XianHong; Wu, JunHua

2015-04-01

Bi-phase dispersible Cu-ZnO hybrid nanoparticles were synthesized by one-pot non-aqueous nanoemulsion with the use of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEO-PPO-PEO) as the surfactant. The transmission electron microscopy (TEM) and X-ray diffraction (XRD) show high crystallinity of the Cu-ZnO hybrid nanoparticles and an average particle size of ~19.4 nm. The ultraviolet-visible light absorbance spectrometry (UV-vis) and photoluminescence spectrophotometry (PL) demonstrate well dispersibility and excellent optical performance of Cu-ZnO hybrid nanoparticles both in organic and aqueous solvent. The X-ray photoelectron spectroscopy (XPS) confirms Cu1+ and Cu2+ in ZnO. The observation using Sudan red (III) as probe molecule reveals that the Cu-ZnO hybrid nanoparticles possess enhanced photocatalytic activity and stability which are promising for potential applications in photocatalysis.

Solar Absorber Cu 2 ZnSnS 4 and its Parent Multilayers ZnS/SnS 2 /Cu 2 S Synthesized by Atomic Layer Deposition and Analyzed by X-ray Photoelectron Spectroscopy

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

Baryshev, Sergey V.; Riha, Shannon C.; Zinovev, Alexander V.

2015-06-01

Presented here are results of x-ray photoelectron spectroscopy (XPS) on multilayers of metal-sulfide binaries ZnS, SnS2, and Cu2S grown by atomic layer deposition (ALD) on Si substrates, and of Cu2ZnSnS4 (CZTS) formed upon 450 °C annealing of the parent multilayer ZnS/SnS2/Cu2S. Survey and detailed spectral analysis of the multilayer ZnS/SnS2/Cu2S are presented step-wise, as each layer was sequentially added by ALD. The set of data is finalized with spectra of the resulting alloy CZTS. XPS analyses indicate significant mixing between SnS2 and Cu2S, which favors CZTS formation within the ALD approach.

ZnCuInS/ZnSe/ZnS quantum dot-based downconversion light-emitting diodes and their thermal effect

DOE PAGES

Liu, Wenyan; Zhang, Yu; Wang, Dan; ...

2015-08-13

The quantum dot-based light-emitting diodes (QD-LEDs) were fabricated using blue GaN chips and red-, yellow-, and green-emitting ZnCuInS/ZnSe/ZnS QDs. The power efficiencies were measured as 14.0 lm/W for red, 47.1 lm/W for yellow, and 62.4 lm/W for green LEDs at 2.6 V. The temperature effect of ZnCuInS/ZnSe/ZnS QDs on these LEDs was investigated using CIE chromaticity coordinates, spectral wavelength, full width at half-maximum (FWHM) and power efficiencies (PE). The thermal quenching induced by the increased surface temperature of the device was confirmed to be one of the important factors to decrease power efficiencies while the CIE chromaticity coordinates changed littlemore » due to the low emission temperature coefficients of 0.022, 0.050 and 0.068 nm/°C for red-, yellow- and green-emitting ZnCuInS/ZnSe/ZnS QDs. Lastly this indicates that ZnCuInS/ZnSe/ZnS QDs are more suitable for down-conversion LEDs compared to CdSe QDs.« less

Chemical Synthesis of ZnS:Cu Nanosheets

NASA Astrophysics Data System (ADS)

Bodo, Bhaskarjyoti; Kalita, P. K.

2010-10-01

ZnS thin films are synthesized through chemical bath deposition (CBD) technique from aqueous solution of ZnSO4 and thiourea mixing in equal volume and equimolar ratio. A 1% CuSO4 solution is mixed with the ZnSO4 solution for doping before the final chemical reaction. SEM image shows the formation of mainly nanosheets, teeth and comb like structures. Absorption studies show red shift of enhanced band gap on Cu doping. Photoluminescence of ZnS:Cu reveals the enhancement of blue luminescence at 468 nm and low intensity green emission at 493 nm which is attributed to more Cu2+ lying in the interstices. XRD shows that the prepared ZnS nanophosphors possess cubic zinc blende structures.

High figure-of-merit p-type transparent conductor, Cu alloyed ZnS via radio frequency magnetron sputtering

NASA Astrophysics Data System (ADS)

Maurya, Sandeep Kumar; Liu, Ya; Xu, Xiaojie; Woods-Robinson, Rachel; Das, Chandan; Ager, Joel W., III; Balasubramaniam, K. R.

2017-12-01

p-type transparent conducting Cu alloyed ZnS thin films from Cu{x} Zn{1-x} S targets (x = 0.1 , 0.2, 0.3, 0.4, and 0.5) were deposited on glass substrates via radio frequency sputtering. x-ray diffraction and TEM-SAED analysis show that all the films have sphalerite ZnS as the majority crystalline phase. In addition, films with 30% and 40% Cu show the presence of increasing amounts of crystalline Cu2S phase. Conductivity values  ⩾400 S cm-1 were obtained for the films having 30% and 40% Cu, with the maximum conductivity of 752 S cm-1 obtained for the film with 40% Cu. Temperature dependent electrical transport measurements indicate metallic as well as degenerate hole conductivity in the deposited films. The reflection-corrected transmittance of this Cu alloyed ZnS (40% Cu) film was determined to be  ⩾75% at 550 nm. The transparent conductor figure of merit (ΦTC ) of the Cu alloyed ZnS (40% Cu), calculated with the average value of transmittance between 1.5 to 2.5 eV, was  ≈276 μS .

Influence of Cu Addition on the Structure, Mechanical and Corrosion Properties of Cast Mg-2%Zn Alloy

NASA Astrophysics Data System (ADS)

Lotfpour, M.; Emamy, M.; Dehghanian, C.; Tavighi, K.

2017-05-01

Effects of different concentrations of Cu on the structure, mechanical and corrosion properties of Mg-2%Zn alloy were studied by the use of x-ray diffraction, optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, standard tensile testing, polarization and electrochemical impedance spectroscopy (EIS) measurements. The average grain size of the alloy decreased from above 1000 μm to about 200 μm with 5 wt.% Cu addition in as-cast condition. Microstructural studies revealed that Mg-2Zn- xCu alloys matrix typically consists of primary α-Mg and MgZnCu and Mg(Zn,Cu)2 intermetallics which are mainly found at the grain boundaries. The results obtained from mechanical testing ascertained that Cu addition increased the hardness values significantly. Although the addition of 0.5 wt.% Cu improved the ultimate tensile strength and elongation values, more Cu addition (i.e., 5 wt.%) weakened the tensile properties of the alloy by introducing semi-continuous network of brittle intermetallic phases. Based on polarization test results, it can be concluded that Cu eliminates a protective film on Mg-2%Zn alloy surface. Among Mg-2%Zn- x%Cu alloys, the one containing 0.1 wt.% Cu exhibited the best anti-corrosion property. However, further Cu addition increased the volume fraction of intermetallics culminating in corrosion rate enhancement due to the galvanic couple effect. EIS and microstructural analysis also confirmed the polarization results.

Green synthesis of CuInS2/ZnS core-shell quantum dots by facile solvothermal route with enhanced optical properties

NASA Astrophysics Data System (ADS)

Jindal, Shikha; Giripunje, Sushama M.; Kondawar, Subhash B.; Koinkar, Pankaj

2018-03-01

We report an eco-friendly green synthesis of highly luminescent CuInS2/ZnS core-shell quantum dots (QDs) with average particle size ∼ 3.9 nm via solvothermal process. The present study embodies the intensification of CuInS2/ZnS QDs properties by the shell growth on the CuInS2 QDs. The as-prepared CuInS2 core and CuInS2/ZnS core-shell QDs have been characterized using a range of optical and structural techniques. By adopting a low temperature growth of CuInS2 core and high temperature growth of CuInS2/ZnS core-shell growth, the tuning of absorption and photoluminescence emission spectra were observed. Optical absorption and photoluminescence spectroscopy probe the effect of ZnS passivation on the electronic structure of the CuInS2 dots. In addition, QDs have been scrutinized using ultra violet photoelectron spectroscopy (UPS) to explore their electronic band structure. The band level positions of CuInS2 and CuInS2/ZnS QDs suffices the demand of non-toxic acceptor material for electronic devices. The variation in electronic energy levels of CuInS2 core with the coating of wide band gap ZnS shell influence the removal of trap assisted recombination on the surface of the core. QDs exhibited tunable emission from red to orange region. These studies reveal the feasibility of QDs in photovoltaic and light emitting diodes.

Effects of Zn²⁺ and Cu²⁺ on loach ovaries and ova development.

PubMed

Tang, Jian-Xun; Li, Jun-Rong; Liu, Zhong-Liang; Zhao, Hua; Tao, Xiao-Min; Cheng, Zhang-Shun

2013-10-01

This study compared the accumulation of Zn²⁺ and Cu²⁺ in the ovaries and ova of loaches under different concentrations of Zn²⁺ (1.00, 2.50 and 5.00 mg/L respectively) and Cu²⁺ (0.10, 0.25 and 0.50 mg/L respectively). The results showed that both Zn²⁺ and Cu²⁺ accumulated in the ovaries, and that the relationship between accumulation and time was linear over 20 days of exposure. The accumulation of the metals in ovaries was closely related to the concentration of exposure in the solutions (P<0.05), and was obviously affected by the time and doses. However, the Cu²⁺ concentration was significantly higher than Zn²⁺ (P<0.05). The development level of ova in the ovaries also correlated with the concentration and exposure period in the Zn²⁺ and Cu²⁺ solutions. This study compared the accumulation of Zn 2+ and Cu 2+ in the ovaries and ova of loaches under different concentrations of Zn 2+ (1.00, 2.50 and 5.00 mg/L respectively) and Cu 2+ (0.10, 0.25 and 0.50 mg/L respectively). The results showed that both Zn 2+ and Cu 2+ accumulated in the ovaries, and that the relationship between accumulation and time was linear over 20 days of exposure. The accumulation of the metals in ovaries was closely related to the concentration of exposure in the solutions ( P< 0.05), and was obviously affected by the time and doses. However, the Cu 2+ concentration was significantly higher than Zn 2+ ( P< 0.05). The development level of ova in the ovaries also correlated with the concentration and exposure period in the Zn 2+ and Cu 2+ solutions.

Synthesis of Cu{sub 2}ZnSnS{sub 4} nanoparticles and controlling the morphology with polyethylene glycol

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

Rawat, Kusum; Department of Electronic Science, University of Delhi South Campus, Delhi 110021; Kim, Hee-Joon

Highlights: • Cu{sub 2}ZnSnS{sub 4} nanoparticles were synthesized by wet chemical technique. • First report on the effect of using polyethylene glycol as a structure directing agent on Cu{sub 2}ZnSnS{sub 4} nanoparticles. • The morphology of Cu{sub 2}ZnSnS{sub 4} nanoparticles changes into nanoflakes and nanorods structures with polyethylene glycol concentration. • Polyethylene glycol assisted Cu{sub 2}ZnSnS{sub 4} nanoparticle film exhibits optical bandgap of 1.5 eV which is suitable for the application in solar cells. - Abstract: Cu{sub 2}ZnSnS{sub 4} nanoparticles were synthesized by wet chemical technique using metal thiourea precursor at 250 °C. The structural and morphological properties of asmore » grown nanoparticles have been characterized by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. The influence of different concentration of polyethylene glycol as structure directing agent on the morphologies of Cu{sub 2}ZnSnS{sub 4} nanoparticles are investigated on thin films deposited by spin coating technique. The mean crystallite size of the Cu{sub 2}ZnSnS{sub 4} nanoparticles was found to improve with polyethylene glycol concentration. Scanning electron microscopy images of Cu{sub 2}ZnSnS{sub 4} revealed aggregated spherical shaped nanoparticles whereas the polyethylene glycol assisted Cu{sub 2}ZnSnS{sub 4} nanoparticle films show nanoflakes and nanorods structures with increasing concentration of polyethylene glycol. Transmission electron microscopy analysis has also been performed to determine the size and structure of nanorods. UV–vis absorption spectroscopy shows the broad band absorption with optical bandgap of 1.50 eV for polyethylene glycol assisted Cu{sub 2}ZnSnS{sub 4} films.« less

In vivo-folded metal-metallothionein 3 complexes reveal the Cu-thionein rather than Zn-thionein character of this brain-specific mammalian metallothionein.

PubMed

Artells, Ester; Palacios, Oscar; Capdevila, Mercè; Atrian, Sílvia

2014-03-01

Metallothionein-3 (MT3) is one of the four mammalian metallothioneins (MT), and is constitutively synthesized in the brain. MT3 acts both intracellularly and extracellularly in this organ, performing functions related to neuronal growth and physiological metal (Zn and Cu) handling. It appears to be involved in the prevention of neurodegenerative disorders caused by insoluble Cu-peptide aggregates, as it triggers a Zn-Cu swap that may counteract the deleterious presence of copper in neural tissues. The literature data on MT3 coordination come from studies either on apo-MT3 reconstitution or the reaction of Zn-MT3 with Cu(2+) , an ion that is hardly present inside cells. To ascertain the MT3 metal-binding features in a scenario closer to the reductive cell cytoplasm, a study of the recombinant Zn(2+) , Cd(2+) and Cu(+) complexes of MT3, βMT3, and αMT3, as well as the in vitro Zn(2+) -Cd(2+) and Zn(2+) -Cu(+) replacement processes, is presented here. We conclude that MT3 has a Cu-thionein character that is stronger than that of the MT1 and MT2 isoforms - also present in the mammalian brain - which is mainly contributed by its β domain. In contrast, the α domain retains a high capacity to bind Zn(2+) ions, and, consequently, the entire MT3 peptide shows a peculiar dual ability to handle both metal ions. The nature of the formed Cu(+) -MT3 complexes oscillates from heterometallic Cu6 Zn4 -MT3 to homometallic Cu10 -MT3 major species, in a narrow Cu concentration range. Therefore, the entire MT3 peptide shows a high capacity to bind Cu(+) , provided that this occurs in a nonoxidative milieux. This reflects a peculiar property of this MT isoform, which accurately senses different Cu contents in the environment in which it is synthesized. © 2014 FEBS.

A full-spectrum photocatalyst with strong near-infrared photoactivity derived from synergy of nano-heterostructured Er3+-doped multi-phase oxides.

PubMed

Chen, Huabin; Liu, Wenxia; Hu, Bin; Qin, Zhuozhuo; Liu, Hong

2017-12-07

The development of full-spectrum photocatalysts active in the near-infrared (NIR) region has gained increasing attention in the photodegradation of organic pollutants. Herein, we designed a full-spectrum photocatalyst with strong NIR photoactivity based on the synergy of Er 3+ -doped ZnO-CuO-ZnAl 2 O 4 multi-phase oxides (Er 3+ -doped Zn/Cu/Al-MPO) via the formation of n-p-n double heterojunctions. The photocatalyst was prepared by synthesizing nanosheets of a Zn/Cu/Al/Er hydrotalcite-like compound (Zn/Cu/Al/Er-HLC) with a co-precipitation method followed by calcination of the nanosheets at 800 °C. The as-prepared Er 3+ -doped Zn/Cu/Al-MPO inherits the nanosheet morphology of Zn/Cu/Al/Er-HLC, and displays over-doubled photoactivity in the entire ultraviolet (UV), visible and NIR regions compared to undoped Zn/Cu/Al-MPO. The excellent photocatalytic activity of Er 3+ -doped Zn/Cu/Al-MPO, especially its strong NIR photoactivity, is ascribed to its Er 3+ -doped CuO-involved multi-crystalline phase heterostructure, i.e., n-p-n double heterojunctions, which does not only offer an enhanced NIR absorption but also promotes the separation of photogenerated charge carriers. Importantly, the synergy of all the parts of the n-p-n double heterojuctions plays an important role in interface band structure regulation for the enhancement of the photocatalytic properties of Er 3+ -doped Zn/Cu/Al-MPO. This work has demonstrated the feasibility of utilizing hydrotalcite-like precursors in the design of full-spectrum photocatalysts active in the NIR region.

Zinc and copper behaviour at the soil-river interface: New insights by Zn and Cu isotopes in the organic-rich Rio Negro basin

NASA Astrophysics Data System (ADS)

Guinoiseau, Damien; Gélabert, Alexandre; Allard, Thierry; Louvat, Pascale; Moreira-Turcq, Patricia; Benedetti, Marc F.

2017-09-01

The complex behaviour of Zn and Cu at the soil-river interface was investigated in soil and riverine water samples from the Rio Negro basin, a secondary tributary of the Rio Amazonas, using their stable isotope compositions. This acidic and organic river drains two types of intensely weathered terrains: podzols in its upstream part, and lateritic soils downstream. Bulk soil particles, suspended particulate matter (SPM) as well as colloidal fractions were sampled across the whole basin during low and high water stages. In the basin, Zn and Cu are mostly exported from lateritic soils and transported by organic colloids where significant losses are observed in the downstream part of the river. The use of δ66Zn and δ65Cu measurements reveals distinct stories for these two metals in suspended sediments and colloids. In the colloids, the constant δ66Zncoll across the basin is induced by the same weak association mode between Zn and organic ligands, regardless of the origin of the water. By contrast, in SPM, the speciation of Zn and thus δ66ZnSPM differ according to the type of drained soils. Zn is associated with organic complexes in particles exported with water draining podzol whereas Zn2+ is incorporated in the structure of the remaining kaolinite clays in lateritic output. The stronger reactivity of Cu than Zn with organic ligands induces its complete complexation. Copper is controlled by refractory particulate organic matter (POM) and by reactive colloidal organic matter; the latter being enriched in 65Cu due to stronger binding interactions than in POM. While the Cu content remains constant in the upstream part of the Rio Negro, downstream, the decrease of SPM and colloidal Cu fluxes is associated with a constant δ65CuSPM and with an increase of δ65Cucoll at the Rio Negro outlet. Geochemical mass balance modelling, based on SPM, Cu and Zn fluxes in SPM and their associated isotopic signatures, confirms distinct host phases for Zn and Cu, and identifies the most probable places where losses of these two metals occur. In colloids, the observed Cu isotope fractionation (from 0.24 to 0.45‰) superimposed on the significant Cucoll loss is assumed to result from a new isotopic equilibrium in a low velocity and high productivity zone: Cu-rich colloids enriched in 63Cu aggregate and settle down, whereas the remaining heavy Cu is partially complexed on strong organic ligands secreted by phytoplankton, forming new Cu-colloids.

Cu0-loaded SBA-15@ZnO with improved electrical properties and affinity towards hydrogen

NASA Astrophysics Data System (ADS)

Bouazizi, N.; Louhichi, S.; Ouargli, R.; Bargougui, R.; Vieillard, J.; Derf, F. Le; Azzouz, A.

2017-05-01

A core-shell material was prepared using SBA-15 crystallites as cores for the growth of a ZnO shell, followed by Cu0 dispersion. The resulting Cu/SBA-15@ZnO nanostructure displayed higher specific surface area (SSA) and higher number of smaller pores as compared to the starting materials. Dispersion of fine Cu0NPs induced a compaction of the host matrice and a marked decay of the hydrophilic character, explained in terms of the involvement of terminal hydroxyl groups in competitive sbnd HO:Cu interaction at the expense of H-bridges with water. Heating at 400-450 °C seems to trigger ZnO dehydroxylation with possible self-polycondensation and/or the formation of Si-O-Zn bridges. This is an additional explanation of the significant SSA increase and decrease in the average pore diameter. Both ZnO and Cu0NP incorporation induced shifts in the UV-vis absorption band towards higher wavelengths, indicating a decrease in the optical band gap energy and an improvement of the conductance properties. As compared to ZnO, Cu0NPs produced stronger improvement of the conductance, which was found to increase with higher frequencies. Cu/SBA-15@ZnO also displayed higher affinity towards hydrogen as compared to SBA-15@ZnO and SBA-15 at ambient conditions. These outstanding properties combined to an appreciable thermal stability are worth to be prone to deeper investigations, because they can open promising prospects for Cu/SBA-15@ZnO as sensor, electrode material, electrocatalyst and/or hydrogen capture matrice.

Endothelial expression of selectins during endotoxin preconditioning.

PubMed

Bauer, P; Welbourne, T; Shigematsu, T; Russell, J; Granger, D N

2000-12-01

Although bacterial endotoxins [lipopolysaccharide (LPS)] can confer tissue resistance to subsequent inflammatory insults, the mechanisms that underlie this LPS-preconditioning (LPS-PC) response remain poorly defined. The dual-radiolabeled monoclonal antibody technique was used to examine whether LPS-PC alters the upregulation (protein) of E- and P-selectins after subsequent LPS challenge. In the gut of wild-type (C57BL/6J) mice, LPS-PC was associated with a reduction in E- (66%) and P-selectin (33%) expression. A similar reduction in E-selectin expression was observed in mutant mice that were genetically deficient in either the endothelial or inducible isoform of nitric oxide synthase or that overexpressed the human gene for Cu/Zn superoxide dismutase. Severe combined immunodeficient mice, genetically devoid of lymphocytes, did exhibit partial inhibition of the LPS-PC response. We conclude that 1) LPS-PC can be demonstrated for E- and P-selectins in some vascular beds (e.g., gut), 2) the mechanism(s) underlying this blunted selectin response does not include a major role for either nitric oxide and superoxide, and 3) circulating lymphocytes may contribute to the LPS-PC response.

DNA strand scission induced by adriamycin and aclacinomycin A.

PubMed

Someya, A; Tanaka, N

1979-08-01

The binding of adriamycin and aclacinomycin A with PM2 DNA, and the consequent cleavage of DNA have been demonstrated by agarose gel electrophoresis, using an ethidium bromide assay. Adriamycin was observed to induce a single strand scission of DNA in the presence of a reducing agent, but aclacinomycin A caused much less degree of DNA breaks. The DNA cleavage was enhanced by Cu2+ and Fe2+, but not significantly by Ni2+, Zn2+, Mg2+ and Ca2+, suggesting that reduction and auto-oxidation of the quinone moiety and H2O2 production participate in the DNA-cutting effect. The DNA degradation was dependent upon concentrations of the anthracyclines and CuCl2. The degree of DNA cleavage at 0.04 mM adriamycin was similar to that at 0.4 mM aclacinomycin A in the presence of 1 mM NADPH and 0.4 mM CuCl2. DNA was degraded to small fragments at 0.4 mM adriamycin and 0.2 mM CuCl2. The anthracycline-induced DNA cleavage was stimulated by H2O2, but partially inhibited by potassium iodide, superoxide dismutase, catalase and nitrogen gas atmosphere. The results suggested that both free radical of anthracycline quinones and hydroxyl radical directly react with DNA strands.

Serpentine endophytic bacterium Pseudomonas azotoformans ASS1 accelerates phytoremediation of soil metals under drought stress.

PubMed

Ma, Ying; Rajkumar, Mani; Moreno, António; Zhang, Chang; Freitas, Helena

2017-10-01

This study evaluates the potential of serpentine endophytic bacterium to foster phytoremediation efficiency of Trifolium arvense grown on multi-metal (Cu, Zn and Ni) contaminated soils under drought stress. A drought resistant endophytic bacterial strain ASS1 isolated from the leaves of Alyssum serpyllifolium grown in serpentine soils was identified as Pseudomonas azotoformans based on biochemical tests and partial 16S rRNA gene sequencing. P. azotoformans ASS1 possessed abiotic stress resistance (heavy metals, drought, salinity, antibiotics and extreme temperature) and plant growth promoting (PGP) properties (phosphate solubilization, nitrogen fixation, production of 1-aminocyclopropane-1-carboxylate deaminase, siderophore and ammonia). Inoculation of T. arvense with ASS1 considerably increased the plant biomass and leaf relative water content in both roll towel assay and pot experiments in the absence and presence of drought stress (DS). In the pot experiments, ASS1 greatly enhanced chlorophyll content, catalase, peroxidase, superoxide dismutase activities, and proline content (only in the absence of drought) in plant leaves, whereas they decreased the concentrations of malondialdehyde. Irrespective of water stress, ASS1 significantly improved accumulation, total removal, bio-concentration factor and biological accumulation coefficient of metals (Cu, Zn and Ni), while decreased translocation factors of Cu. The effective colonization and survival in the rhizosphere and tissue interior assured improved plant growth and successful metal phytoremediation under DS. These results demonstrate the potential of serpentine endophytic bacterium ASS1 for protecting plants against abiotic stresses and helping plants to thrive in semiarid ecosystems and accelerate phytoremediation process in metal polluted soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

Growth of Cu2ZnSnSe4 Film under Controllable Se Vapor Composition and Impact of Low Cu Content on Solar Cell Efficiency.

PubMed

Li, Jianjun; Wang, Hongxia; Wu, Li; Chen, Cheng; Zhou, Zhiqiang; Liu, Fangfang; Sun, Yun; Han, Junbo; Zhang, Yi

2016-04-27

It is a challenge to fabricate high quality Cu2ZnSnSe4 (CZTSe) film with low Cu content (Cu/(Zn + Sn) < 0.8). In this work, the growth mechanisms of CZTSe films under different Se vapor composition are investigated by DC-sputtering and a postselenization approach. The composition of Se vapor has important influence on the compactability of the films and the diffusion of elements in the CZTSe films. By adjusting the composition of Se vapor during the selenization process, an optimized two step selenization process is proposed and highly crystallized CZTSe film with low Cu content (Cu/(Zn + Sn) = 0.75) is obtained. Further study of the effect of Cu content on the morphology and photovoltaic performance of the corresponding CZTSe solar cells has shown that the roughness of the CZTSe absorber film increases when Cu content decreases. As a consequence, the reflection loss of CZTSe solar cells reduces dramatically and the short circuit current density of the cells improve from 34.7 mA/cm(2) for Cu/(Zn + Sn) = 0.88 to 38.5 mA/cm(2) for Cu/(Zn + Sn) = 0.75. In addition, the CZTSe solar cells with low Cu content show longer minority carrier lifetime and higher open circuit voltage than the high Cu content devices. A champion performance CZTSe solar cell with 10.4% efficiency is fabricated with Cu/(Zn + Sn) = 0.75 in the CZTSe film without antireflection coating.

Rapid, controllable, one-pot and room-temperature aqueous synthesis of ZnO:Cu nanoparticles by pulsed UV laser and its application for photocatalytic degradation of methyl orange.

PubMed

Arabi, Mozhgan; Baizaee, Seyyed Mahdy; Bahador, Alireza; Otaqsara, Seyed Mohammad Taheri

2018-05-01

Zinc oxide (ZnO) and ZnO:Cu nanoparticles (NPs) were synthesized using a rapid, controllable, one-pot and room-temperature pulsed UV-laser assisted method. UV-laser irradiation was used as an effective energy source in order to gain better control over the NPs size and morphology in aqueous media. Parameters effective in laser assisted synthesis of NPs such as irradiation time and laser shot repetition rate were optimized. Photoluminescence (PL) spectra of ZnO NPs showed a broad emission with two trap state peaks located at 442 and 485 nm related to electronic transition from zinc interstitial level (I Zn ) to zinc vacancy level (V Zn ) and electronic transition from conduction band to the oxygen vacancy level (V O ), respectively. For ZnO:Cu NPs, trap state emissions disappeared completely and a copper (Cu)-related emission appeared. PL intensity of Cu-related emission increased with the increase in concentration of Cu 2+ , so that for molar ratio of Cu:Zn 2%, optimal value of PL intensity was obtained. The photocatalytic activity of Cu-doped ZnO revealed 50 and 100% increasement than that of undoped NPs under UV and visible irradiation, respectively. The enhanced photocatalytic activity could be attributed to smaller crystal size, as well as creation of impurity acceptor levels (T 2 ) inside the ZnO energy band gap. Copyright © 2017 John Wiley & Sons, Ltd.

Nanosized CuO and ZnO catalyst supported on titanium chip for conversion of carbon dioxide to methyl alcohol.

PubMed

Seo, Hyeong-Seok; Park, Chul-Min; Kim, Ki-Joong; Jeong, Woon-Jo; Chung, Min-Chul; Jung, Sang-Chul; Kim, Sang-Chai; Ahn, Ho-Geun

2013-08-01

In order to reutilize spent metallic titanium chips (TC) as catalyst support or photocatalytic materials, the surface of the TC was modified by thermal treatment under air atmosphere. TC-supported nanosized CuO and ZnO catalysts were prepared by impregnation (IMP) and co-precipitation (CP) method, respectively. The catalytic activity for CO2 hydrogenation to CH3OH was investigated using a flow-typed reactor under various reaction pressures. The crystals of CuO and ZnO was well formed on TC. CO2 conversion, CH3OH selectivity, and CH3OH yield were obtained as a function of time on stream over CuO-ZnO/TC catalysts. Conversion of CO2 to CH3OH over CuO-ZnO/TC catalyst by CP method and CuO/ZnO/TC catalyst by IMP method were ca. 16% and ca. 12%, respectively. Conversion of CO2 over CuO-ZnO/TC catalyst by CP method was increased with increasing reaction temperature in the range of 15-30 atm. Maximum selectivity and yield to CH3OH over CuO-ZnO/TC at 250 degrees C were ca. 90% at 20 atm and ca. 18.2% at 30 atm, respectively.

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

PubMed Central

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

2012-01-01

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

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

PubMed

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

2012-12-01

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

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

PubMed

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

2012-01-01

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

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

PubMed Central

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

2014-01-01

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

Ultrasensitive non-enzymatic glucose sensor based on three-dimensional network of ZnO-CuO hierarchical nanocomposites by electrospinning

PubMed Central

Zhou, Chunyang; Xu, Lin; Song, Jian; Xing, Ruiqing; Xu, Sai; Liu, Dali; Song, Hongwei

2014-01-01

Three-dimensional (3D) porous ZnO–CuO hierarchical nanocomposites (HNCs) nonenzymatic glucose electrodes with different thicknesses were fabricated by coelectrospinning and compared with 3D mixed ZnO/CuO nanowires (NWs) and pure CuO NWs electrodes. The structural characterization revealed that the ZnO–CuO HNCs were composed of the ZnO and CuO mixed NWs trunk (~200 nm), whose outer surface was attached with small CuO nanoparticles (NPs). Moreover, a good synergetic effect between CuO and ZnO was confirmed. The nonenzymatic biosensing properties of as prepared 3D porous electrodes based on fluorine doped tin oxide (FTO) were studied and the results indicated that the sensing properties of 3D porous ZnO–CuO HNCs electrodes were significantly improved and depended strongly on the thickness of the HNCs. At an applied potential of + 0.7 V, the optimum ZnO–CuO HNCs electrode presented a high sensitivity of 3066.4 μAmM−1cm−2, the linear range up to 1.6 mM, and low practical detection limit of 0.21 μM. It also showed outstanding long term stability, good reproducibility, excellent selectivity and accurate measurement in real serum sample. The formation of special hierarchical heterojunction and the well-constructed 3D structure were the main reasons for the enhanced nonenzymatic biosensing behavior. PMID:25488502

Electrical Study of Trapped Charges in Copper-Doped Zinc Oxide Films by Scanning Probe Microscopy for Nonvolatile Memory Applications

PubMed Central

Su, Ting; Zhang, Haifeng

2017-01-01

Charge trapping properties of electrons and holes in copper-doped zinc oxide (ZnO:Cu) films have been studied by scanning probe microscopy. We investigated the surface potential dependence on the voltage and duration applied to the copper-doped ZnO films by Kelvin probe force microscopy. It is found that the Fermi Level of the 8 at.% Cu-doped ZnO films shifted by 0.53 eV comparing to undoped ZnO films. This shift indicates significant change in the electronic structure and energy balance in Cu-doped ZnO films. The Fermi Level (work function) of zinc oxide films can be tuned by Cu doping, which are important for developing this functional material. In addition, Kelvin probe force microscopy measurements demonstrate that the nature of contact at Pt-coated tip/ZnO:Cu interface is changed from Schottky contact to Ohmic contact by increasing sufficient amount of Cu ions. The charge trapping property of the ZnO films enhance greatly by Cu doping (~10 at.%). The improved stable bipolar charge trapping properties indicate that copper-doped ZnO films are promising for nonvolatile memory applications. PMID:28135335

Study on room temperature gas-sensing performance of CuO film-decorated ordered porous ZnO composite by In2O3 sensitization

NASA Astrophysics Data System (ADS)

Li, Tian-tian; Bao, Na; Geng, Ai-fang; Yu, Hui; Yang, Ying; Dong, Xiang-ting

2018-02-01

For the first time, ordered mesoporous ZnO nanoparticles have been synthesized by a template method. The electroplating after chemical plating method was creatively used to form copper film on the surface of the prepared ZnO, and then a CuO film-decorated ordered porous ZnO composite (CuO/ZnO) was obtained by a high-temperature oxidation method. In2O3 was loaded into the prepared CuO film-ZnO by an ultrasonic-assisted method to sensitize the room temperature gas-sensing performance of the prepared CuO/ZnO materials. The doped In2O3 could effectively improve the gas-sensing properties of the prepared materials to nitrogen oxides (NOx) at room temperature. The 1% In2O3 doped CuO/ZnO sample (1 wt% In2O3-CuO/ZnO) showed the best gas-sensing properties whose response to 100 ppm NOx reached 82%, and the detectable minimum concentration reached 1 ppm at room temperature. The prepared materials had a good selectivity, better response, very low detection limit, and high sensitivity to NOx gas at room temperature, which would have a great development space in the gas sensor field and a great research value.

Magnetically engineered Cd-free quantum dots as dual-modality probes for fluorescence/magnetic resonance imaging of tumors.

PubMed

Ding, Ke; Jing, Lihong; Liu, Chunyan; Hou, Yi; Gao, Mingyuan

2014-02-01

Magnetically engineered Cd-free CuInS2@ZnS:Mn quantum dots (QDs) were designed, synthesized, and evaluated as potential dual-modality probes for fluorescence and magnetic resonance imaging (MRI) of tumors in vivo. The synthesis of Mn-doped core-shell structured CuInS2@ZnS mainly comprised three steps, i.e., the preparation of fluorescent CuInS2 seeds, the particle surface coating of ZnS, and the Mn-doping of the ZnS shells. Systematic spectroscopy studies were carried out to illustrate the impacts of ZnS coating and the following Mn-doping on the optical properties of the QDs. In combination with conventional fluorescence, fluorescence excitation, and time-resolved fluorescence measurements, the structure of CuInS2@ZnS:Mn QDs prepared under optimized conditions presented a Zn gradient CuInS2 core and a ZnS outer shell, while Mn ions were mainly located in the ZnS shell, which well balanced the optical and magnetic properties of the resultant QDs. For the following in vivo imaging experiments, the hydrophobic CuInS2@ZnS:Mn QDs were transferred into water upon ligand exchange reactions by replacing the 1-dodecanethiol ligand with dihydrolipoic acid-poly(ethylene glycol) (DHLA-PEG) ligand. The MTT assays based on HeLa cells were carried out to evaluate the cytotoxicity of the current Cd-free CuInS2@ZnS:Mn QDs for comparing with that of water soluble CdTe QDs. Further in vivo fluorescence and MR imaging experiments suggested that the PEGylated CuInS2@ZnS:Mn QDs could well target both subcutaneous and intraperitoneal tumors in vivo. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dietary nitrate protects submandibular gland from hyposalivation in ovariectomized rats via suppressing cell apoptosis.

PubMed

Xu, Yipu; Pang, Baoxing; Hu, Liang; Feng, Xiaoyu; Hu, Lei; Wang, Jingsong; Zhang, Chunmei; Wang, Songlin

2018-02-26

Xerostomia, a major oral symptom of menopause, is a subjective feeling of dry mouth associated with oral pain and difficulties in deglutition and speech, which significantly reduces patient's quality of life. Dietary nitrate, which can be converted to nitric oxide, has multiple physiological functions in the body, including antioxidant activity and vasodilatation; however, its protective effect against xerostomia remains poorly understood. The present study aimed to evaluate the effects of dietary nitrate on estrogen deficiency-induced xerostomia. We established an ovariectomized (OVX) rat model, which included five groups: sham-operated, OVX, OVX + 0.4 mM nitrate, OVX + 2 mM nitrate, and OVX + 4 mM nitrate (n = 6). After ovariectomy, animals in the nitrate treatment groups received appropriate amounts of sodium nitrate dissolved in distilled water for 3 months. The results showed that nitrate treatment reduced body weight and water intake, and increased serum nitrate and nitrite levels. Furthermore, nitrate uptake increased saliva secretion as evidenced by saliva flow rates and aquaporin 5 expression, and alleviated histological lesions as evidenced by reduction of the fibrotic area and cell atrophy in the salivary glands. Although protective effects of nitrate against estrogen deficiency-induced xerostomia were observed at all doses, treatment with 2 mM nitrate was more effective than that with 0.4 mM and 4 mM nitrate. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) and caspase-3 expression analyses showed that nitrate also protected cells from apoptosis, possibly through upregulation of Cu-Zn superoxide dismutase (Cu-Zn SOD) known to inhibit oxidative stress-related apoptosis. Our findings indicate that nitrate could improve functional activity of the salivary glands in OVX rats by suppressing apoptosis and upregulating Cu-Zn SOD expression, suggesting that dietary nitrate may potentially prevent hyposalivation in menopausal women. Copyright © 2018. Published by Elsevier Inc.

Mechanisms of TNFalpha-induced cardiac dysfunction in cholestatic bile duct-ligated mice: interaction between TNFalpha and endocannabinoids.

PubMed

Yang, Ying-Ying; Liu, Hongqun; Nam, Soon Woo; Kunos, George; Lee, Samuel S

2010-08-01

Chronic liver disease is associated with endotoxemia, oxidative stress, increased endocannabinoids and decreased cardiac responsiveness. Endocannabinoids activate the tumor necrosis factor-alpha (TNFalpha)-nuclear factor kappaB (NFkappaB) pathway. However, how they interact with each other remains obscure. We therefore aimed to clarify the relationship between the TNFalpha-NFkappaB pathway and endocannabinoids in the pathogenesis of cardiodepression of cholestatic bile duct ligated (BDL) mice. BDL mice with TNFalpha knockout (TNFalpha-/-) and infusion of anti-TNFalpha antibody were used. Cardiac mRNA and protein expression of NFkappaBp65, c-Jun-N-terminal kinases (JNK), p38 mitogen-activated protein kinase (p38MAPK), extracelullar-signal- regulated kinase (ERK), inducible nitric oxide synthase (iNOS), Copper/Zinc and Magnesium-superoxide dismutase (Cu/ Zn- and Mn-SOD), cardiac anandamide, 2-arachidonoylglycerol (2-AG), nitric oxide (NOx) and glutathione, and plasma TNFalpha were measured. The effects of TNFalpha, cannabinoid receptor (CB1) antagonist AM251 and the endocannabinoid reuptake inhibitor UCM707, on the contractility of isolated cardiomyocytes, were assessed. In BDL mice, cardiac mRNA and protein expression of NFkappaBp65, p38MAPK, iNOS, NOx, anandamide, and plasma TNFa were increased, whereas glutathione, Cu/Zn-SOD, and Mn-SOD were decreased. Cardiac contractility was blunted in BDL mice. Anti-TNFa treatment in BDL mice decreased cardiac anandamide and NOx, reduced expression of NFkappaBp65, p38MAPK, and iNOS, enhanced expression of Cu/Zn-SOD and Mn-SOD, increased reductive glutathione and restored cardiomyocyte contractility. TNFa-depressed contractility was worsened by UCM707, whereas AM251 improved contractility. Increased TNFalpha, acting via NFkappaB-iNOS and p38MAPK signaling pathways, plays an important role in the pathogenesis of cardiodepression in BDL mice. TNFalpha also suppressed contractility by increasing oxidative stress and endocannabinoid activity.

Activation of immunity, immune response, antioxidant ability, and resistance against Vibrio alginolyticus in white shrimp Litopenaeus vannamei decrease under long-term culture at low pH.

PubMed

Chen, Yu-Yuan; Chen, Jiann-Chu; Tseng, Kuei-Chi; Lin, Yong-Chin; Huang, Chien-Lun

2015-10-01

The growth, activation of immunity, immune parameters, and transcript levels of cytMnSOD, mtMnSOD, ecCuZnSOD, glutathione peroxidase (GPx), catalase, lysozyme, and penaeidin 3a were examined in white shrimp Litopenaeus vannamei reared at pH 6.8 and 8.1 after 24 weeks. No significant difference in growth was observed between the two groups. An in vitro study indicated that phenoloxidase activity and respiratory bursts (RB, release of the superoxide anion) were significantly higher in the haemocytes of pH 8.1 shrimp (shrimp reared at pH 8.1) than in pH 6.8 shrimp (shrimp reared at pH 6.8). An in vivo study indicated that the levels of immune parameters of pH 8.1 shrimp were significantly higher than in pH 6.8 shrimp, and the transcript levels of cytMnSOD, ecCuZnSOD, glutathione peroxidase, lysozyme, and penaeidin 3a were down-regulated in pH 6.8 shrimp. In another experiment, shrimp reared at pH 6.8 and 8.1 for 24 weeks were challenged with Vibrio alginolyticus. The mortality rate of pH 6.8 shrimp was significantly higher than in pH 8.1 shrimp over 12-168 h. Phagocytic activity, phagocytic index, and clearance efficiency to V. alginolyticus were significantly lower in pH 6.8 shrimp. We concluded that shrimp under long-term culture at pH 6.8 exhibited decreased resistance against V. alginolyticus as evidenced by reductions in the activation of immunity and immune parameters together with decreased transcript levels of cytMnSOD, ecCuZnSOD, GPx, lysozyme, and penaeidin 3a. Copyright © 2015 Elsevier Ltd. All rights reserved.

Association between enzymatic and non-enzymatic antioxidant defense mechanism with apolipoprotein E genotypes in Alzheimer disease.

PubMed

Kharrazi, Hadi; Vaisi-Raygani, Asad; Rahimi, Zohreh; Tavilani, Haidar; Aminian, Mahdi; Pourmotabbed, Tayebeh

2008-08-01

There are evidence suggesting that APOE-varepsilon4 allele play an important role in the pathogenesis of Alzheimer's disease (AD) by reducing peripheral levels and activities of a broad spectrum of nonenzymatic and enzymatic antioxidants systems. However, the link between APOE genotype, oxidative stress, and AD has yet to be established. In this study we examined whether antioxidant defense mechanism exacerbates the risk of AD in individual carrying APOE-varepsilon4 allele in a population from Tehran, Iran. We determined the enzymatic activities of the erythrocyte Cu-Zn superoxide dismutase (Cu-Zn SOD), glutathione peroxidase (GSH-Px), catalase (CAT) and serum level of total antioxidant status(TAS) in various APOE genotypes in 91 patients with AD and 91 healthy subjects as control group (age and sex-matched). The results showed that the TAS level and the activities of enzymatic antioxidants CAT and GSH-Px were significantly lower and the SOD activity was significantly higher in AD patients compared to controls. The AD patients with APOE-varepsilon4 allele genotype had significantly lower serum TAS concentration and lower erythrocytes GSH-Px and CAT activities (p=0.001) but significantly higher erythrocytes Cu-Zn SOD activity (p=0.001) than the non-APOE-varepsilon4 carrier AD and the control group. In addition, the association observed between the factors involved in an antioxidant defense mechanism and APOE-varepsilon4 allele in AD increased with age of the subjects. These data indicate that the reduced serum level of TAS and activity of CAT, GSH-Px and increased SOD exacerbate the risk of AD in individuals carrying APOE-varepsilon4 allele. The reduced antioxidants defense in APOE-varepsilon4 allele carrier may contribute to beta-amyloidosis. This effect, however, is more pronounced in the AD patients older than 75 years of age. This suggests that a therapeutic modality should be considered for these subjects.

Comparison of Whole Body SOD1 Knockout with Muscle-Specific SOD1 Knockout Mice Reveals a Role for Nerve Redox Signaling in Regulation of Degenerative Pathways in Skeletal Muscle.

PubMed

Sakellariou, Giorgos K; McDonagh, Brian; Porter, Helen; Giakoumaki, Ifigeneia I; Earl, Kate E; Nye, Gareth A; Vasilaki, Aphrodite; Brooks, Susan V; Richardson, Arlan; Van Remmen, Holly; McArdle, Anne; Jackson, Malcolm J

2018-02-01

Lack of Cu,Zn-superoxide dismutase (CuZnSOD) in homozygous knockout mice (Sod1 -/- ) leads to accelerated age-related muscle loss and weakness, but specific deletion of CuZnSOD in skeletal muscle (mSod1KO mice) or neurons (nSod1KO mice) resulted in only mild muscle functional deficits and failed to recapitulate the loss of mass and function observed in Sod1 -/- mice. To dissect any underlying cross-talk between motor neurons and skeletal muscle in the degeneration in Sod1 -/- mice, we characterized neuromuscular changes in the Sod1 -/- model compared with mSod1KO mice and examined degenerative molecular mechanisms and pathways in peripheral nerve and skeletal muscle. In contrast to mSod1KO mice, myofiber atrophy in Sod1 -/- mice was associated with increased muscle oxidative damage, neuromuscular junction degeneration, denervation, nerve demyelination, and upregulation of proteins involved in maintenance of myelin sheaths. Proteomic analyses confirmed increased proteasomal activity and adaptive stress responses in muscle of Sod1 -/- mice that were absent in mSod1KO mice. Peripheral nerve from neither Sod1 -/- nor mSod1KO mice showed increased oxidative damage or molecular responses to increased oxidation compared with wild type mice. Differential cysteine (Cys) labeling revealed a specific redox shift in the catalytic Cys residue of peroxiredoxin 6 (Cys47) in the peripheral nerve from Sod1 -/- mice. Innovation and Conclusion: These findings demonstrate that neuromuscular integrity, redox mechanisms, and pathways are differentially altered in nerve and muscle of Sod1 -/- and mSod1KO mice. Results support the concept that impaired redox signaling, rather than oxidative damage, in peripheral nerve plays a key role in muscle loss in Sod1 -/- mice and potentially sarcopenia during aging. Antioxid. Redox Signal. 28, 275-295.

Chronic administration of fluoxetine or clozapine induces oxidative stress in rat liver: a histopathological study.

PubMed

Zlatković, Jelena; Todorović, Nevena; Tomanović, Nada; Bošković, Maja; Djordjević, Snežana; Lazarević-Pašti, Tamara; Bernardi, Rick E; Djurdjević, Aleksandra; Filipović, Dragana

2014-08-01

Chronic exposure to stress contributes to the etiology of mood disorders, and the liver as a target organ of antidepressant and antipsychotic drug metabolism is vulnerable to drug-induced toxicity. We investigated the effects of chronic administration of fluoxetine (15mg/kg/day) or clozapine (20mg/kg/day) on liver injury via the measurement of liver enzymes, oxidative stress and histopathology in rats exposed to chronic social isolation (21days), an animal model of depression, and controls. The activity of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), the liver content of carbonyl groups, malonyldialdehyde (MDA), reduced glutathione (GSH), cytosolic glutathione S-transferase (GST) and nitric oxide (NO) metabolites were determined. We also characterized nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2) and CuZn-superoxide dismutase (CuZnSOD) protein expression as well as histopathological changes. Increased serum ALT activity in chronically-isolated and control animals treated with both drugs was found while increased AST activity was observed only in fluoxetine-treated rats (chronically-isolated and controls). Increased carbonyl content, MDA, GST activity and decreased GSH levels in drug-treated controls/chronically-isolated animals suggest a link between drugs and hepatic oxidative stress. Increased NO levels associated with NF-κB activation and the concomitant increased COX-2 expression together with compromised CuZnSOD expression in clozapine-treated chronically-isolated rats likely reinforce oxidative stress, observed by increased lipid peroxidation and GSH depletion. In contrast, fluoxetine reduced NO levels in chronically-isolated rats. Isolation induced oxidative stress but histological changes were similar to those observed in vehicle-treated controls. Chronic administration of fluoxetine in both chronically-isolated and control animals resulted in more or less normal hepatic architecture, while clozapine in both groups resulted in liver injury. These data suggest that clozapine appears to have a higher potential to induce liver toxicity than fluoxetine. Copyright © 2014 Elsevier B.V. All rights reserved.

Subcellular metal imaging identifies dynamic sites of Cu accumulation in Chlamydomonas

DOE PAGES

Hong-Hermesdorf, Anne; Miethke, Marcus; Gallaher, Sean D.; ...

2014-10-26

Here we identified a Cu-accumulating structure with a dynamic role in intracellular Cu homeostasis. During Zn limitation, Chlamydomonas reinhardtii hyperaccumulates Cu, a process dependent on the nutritional Cu sensor CRR1, but it is functionally Cu deficient. Visualization of intracellular Cu revealed major Cu accumulation sites coincident with electron-dense structures that stained positive for low pH and polyphosphate, suggesting that they are lysosome-related organelles. Nano-secondary ion MS showed colocalization of Ca and Cu, and X-ray absorption spectroscopy was consistent with Cu + accumulation in an ordered structure. Zn resupply restored Cu homeostasis concomitant with reduced abundance of these structures. Cu isotopemore » labeling demonstrated that sequestered Cu + became bioavailable for the synthesis of plastocyanin, and transcriptome profiling indicated that mobilized Cu became visible to CRR1. Cu trafficking to intracellular accumulation sites may be a strategy for preventing protein mismetallation during Zn deficiency and enabling efficient cuproprotein metallation or remetallation upon Zn resupply.« less

IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

DOE PAGES

Schumann, Julia; Kröhnert, Jutta; Frei, Elias; ...

2017-08-28

Carbon monoxide was applied as probe molecule to compare the surface of a ZnO-containing (Cu/ZnO:Al) and a ZnO-free (Cu/MgO) methanol synthesis catalyst (copper content 70 atomic %) after reduction in hydrogen at 523 K by DRIFT spectroscopy. Nano-structured, mainly metallic copper was detected on the surface of the Cu/MgO catalyst. In contrast, the high energy of the main peak in the spectrum of CO adsorbed on reduced Cu/ZnO:Al (2125 cm -1) proves that metallic copper is largely absent on the surface of this catalyst. The band is assigned to Zn δ+–CO. The presence of not completely reduced Cu δ+–CO speciesmore » cannot be excluded. The results are interpreted in terms of a partial coverage of the copper nano-particles in the Cu/ZnO:Al catalyst by a thin layer of metastable, defective zinc oxide. Minor contributions in the spectrum at 2090 and 2112 cm -1 due to nano-structured Cu 0–CO and CO adsorbed on highly defective Cu 0, respectively, indicate that the coverage of metallic copper is not complete.« less

IR-Spectroscopic Study on the Interface of Cu-Based Methanol Synthesis Catalysts: Evidence for the Formation of a ZnO Overlayer

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

Schumann, Julia; Kröhnert, Jutta; Frei, Elias

Carbon monoxide was applied as probe molecule to compare the surface of a ZnO-containing (Cu/ZnO:Al) and a ZnO-free (Cu/MgO) methanol synthesis catalyst (copper content 70 atomic %) after reduction in hydrogen at 523 K by DRIFT spectroscopy. Nano-structured, mainly metallic copper was detected on the surface of the Cu/MgO catalyst. In contrast, the high energy of the main peak in the spectrum of CO adsorbed on reduced Cu/ZnO:Al (2125 cm -1) proves that metallic copper is largely absent on the surface of this catalyst. The band is assigned to Zn δ+–CO. The presence of not completely reduced Cu δ+–CO speciesmore » cannot be excluded. The results are interpreted in terms of a partial coverage of the copper nano-particles in the Cu/ZnO:Al catalyst by a thin layer of metastable, defective zinc oxide. Minor contributions in the spectrum at 2090 and 2112 cm -1 due to nano-structured Cu 0–CO and CO adsorbed on highly defective Cu 0, respectively, indicate that the coverage of metallic copper is not complete.« less

Interplay of Cu and oxygen vacancy in optical transitions and screening of excitons in ZnO:Cu films

NASA Astrophysics Data System (ADS)

Darma, Yudi; Seng Herng, Tun; Marlina, Resti; Fauziah, Resti; Ding, Jun; Rusydi, Andrivo

2014-02-01

We study room temperature optics and electronic structures of ZnO:Cu films as a function of Cu concentration using a combination of spectroscopic ellipsometry, photoluminescence, and ultraviolet-visible absorption spectroscopy. Mid-gap optical states, interband transitions, and excitons are observed and distinguishable. We argue that the mid-gap states are originated from interactions of Cu and oxygen vacancy (Vo). They are located below conduction band (Zn4s) and above valence band (O2p) promoting strong green emission and narrowing optical band gap. Excitonic states are screened and its intensities decrease upon Cu doping. Our results show the importance of Cu and Vo driving the electronic structures and optical transitions in ZnO:Cu films.

Hints for Metal-Preference Protein Sequence Determinants: Different Metal Binding Features of the Five Tetrahymena thermophila Metallothioneins

PubMed Central

Espart, Anna; Marín, Maribel; Gil-Moreno, Selene; Palacios, Òscar; Amaro, Francisco; Martín-González, Ana; Gutiérrez, Juan C.; Capdevila, Mercè; Atrian, Sílvia

2015-01-01

The metal binding preference of metallothioneins (MTs) groups them in two extreme subsets, the Zn/Cd- and the Cu-thioneins. Ciliates harbor the largest MT gene/protein family reported so far, including 5 paralogs that exhibit relatively low sequence similarity, excepting MTT2 and MTT4. In Tetrahymena thermophila, three MTs (MTT1, MTT3 and MTT5) were considered Cd-thioneins and two (MTT2 and MTT4) Cu-thioneins, according to gene expression inducibility and phylogenetic analysis. In this study, the metal-binding abilities of the five MTT proteins were characterized, to obtain information about the folding and stability of their cognate- and non-cognate metal complexes, and to characterize the T. thermophila MT system at protein level. Hence, the five MTTs were recombinantly synthesized as Zn2+-, Cd2+- or Cu+-complexes, which were analyzed by electrospray mass spectrometry (ESI-MS), circular dichroism (CD), and UV-vis spectrophotometry. Among the Cd-thioneins, MTT1 and MTT5 were optimal for Cd2+ coordination, yielding unique Cd17- and Cd8- complexes, respectively. When binding Zn2+, they rendered a mixture of Zn-species. Only MTT5 was capable to coordinate Cu+, although yielding heteronuclear Zn-, Cu-species or highly unstable Cu-homometallic species. MTT3 exhibited poor binding abilities both for Cd2+ and for Cu+, and although not optimally, it yielded the best result when coordinating Zn2+. The two Cu-thioneins, MTT2 and MTT4 isoforms formed homometallic Cu-complexes (major Cu20-MTT) upon synthesis in Cu-supplemented hosts. Contrarily, they were unable to fold into stable Cd-complexes, while Zn-MTT species were only recovered for MTT4 (major Zn10-MTT4). Thus, the metal binding preferences of the five T. thermophila MTs correlate well with their previous classification as Cd- and Cu-thioneins, and globally, they can be classified from Zn/Cd- to Cu-thioneins according to the gradation: MTT1>MTT5>MTT3>MTT4>MTT2. The main mechanisms underlying the evolution and specialization of the MTT metal binding preferences may have been internal tandem duplications, presence of doublet and triplet Cys patterns in Zn/Cd-thioneins, and optimization of site specific amino acid determinants (Lys for Zn/Cd- and Asn for Cu-coordination). PMID:25798065

Changing the thickness of two layers: i-ZnO nanorods, p-Cu2O and its influence on the carriers transport mechanism of the p-Cu2O/i-ZnO nanorods/n-IGZO heterojunction.

PubMed

Ke, Nguyen Huu; Trinh, Le Thi Tuyet; Phung, Pham Kim; Loan, Phan Thi Kieu; Tuan, Dao Anh; Truong, Nguyen Huu; Tran, Cao Vinh; Hung, Le Vu Tuan

2016-01-01

In this study, two layers: i-ZnO nanorods and p-Cu2O were fabricated by electrochemical deposition. The fabricating process was the initial formation of ZnO nanorods layer on the n-IGZO thin film which was prepared by sputtering method, then a p-Cu2O layer was deposited on top of rods to form the p-Cu2O/i-ZnO nanorods/n-ZnO heterojunction. The XRD, SEM, UV-VIS, I-V characteristics methods were used to define structure, optical and electrical properties of these heterojunction layers. The fabricating conditions and thickness of the Cu2O layers significantly affected to the formation, microstructure, electrical and optical properties of the junction. The length of i-ZnO nanorods layer in the structure of the heterojunction has strongly affected to the carriers transport mechanism and performance of this heterojunction.

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

Wu, Wenting; Zhang, Qinggang; Wang, Ruiqin

Unsaturated metal species (UMS) confined in nanomaterials play important roles for electron transfer in a wide range of catalytic reactions. However, the limited fabrication methods of UMS restrict their wider catalytic applications. Here in this paper, we report on the synergy of unsaturated Zn and Cu dopants confined in carbon dots (ZnCu-CDs) to produce enhanced electron transfer and photooxidation processes in the doped CDs. The Zn/Cu species chelate with the carbon matrix mainly through Cu-O(N)-Zn-O(N)-Cu complexes. Within this structure, Cu 2+ acts as a mild oxidizer that facilely increases the unsaturated Zn content and also precisely tunes the unsaturated Znmore » valence state to Zn d+, where d is between 1 and 2, instead of Zn. With the help of UMS, electron-transfer pathways are produced, enhancing both the electron donating (7.0 times) and-accepting (5.3 times) abilities relative to conventional CDs. Because of these synergistic effects, the photocatalytic efficiency of CDs in photooxidation reactions is shown to improve more than 5-fold.« less

Physiological and biochemical responses of Salix integra Thunb. under copper stress as affected by soil flooding.

PubMed

Cao, Yini; Ma, Chuanxin; Chen, Guangcai; Zhang, Jianfeng; Xing, Baoshan

2017-06-01

To explore the joint effect of copper (Cu) and flooding on Salix integra Thunb. (S. integra), the physiological and biochemical parameters of the seedlings grown in Cu amended soil (50, 150, 450 mg kg -1 ) with or without the flooding for 60 days were evaluated. The results suggested that the flooding significantly inhibited the root growth in terms of root length and root tips. The Cu exposures of 50 and 150 mg kg -1 notably enhanced the root growth as compared to the control. Majority of Cu was accumulated in S. integra roots, while flooding significantly reduced the Cu content, except the 150 mg kg -1 Cu treatment, but the iron (Fe) and manganese (Mn) content on the root surface were both markedly increased relative to non-flooded control. The malonaldehyde (MDA) and glutathione (GSH) contents in leaves showed a dose-response upon Cu exposure. Soil flooding enhanced the GSH level, which displayed 4.50-49.59% increases compared to its respective non-flooded treatment, while no difference was evident on MDA contents between the flooding and the non-flooded treatments. Both superoxide dismutase (SOD) and peroxidase (POD) activities were boosted while the catalase (CAT) was suppressed with increasing Cu exposure dose, and soil flooding reduced the POD and CAT activities. The elevated Cu level caused the evident increases of root calcium (Ca), potassium (K), and sulfur (S) concentrations and decreases of root phosphorus (P), sodium (Na), and zinc (Zn) concentrations. Soil flooding increased the concentrations of Fe, S, Na, Ca, and magnesium (Mg) in S. integra root. Taken together, our results suggested S. integra has high tolerance to the joint stress from Cu and flooding. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comment on "Active sites for CO2 hydrogenation to methanol on Cu/ZnO catalysts".

PubMed

Nakamura, Junji; Fujitani, Tadahiro; Kuld, Sebastian; Helveg, Stig; Chorkendorff, Ib; Sehested, Jens

2017-09-01

Kattel et al (Reports, 24 March 2017, p. 1296) report that a zinc on copper (Zn/Cu) surface undergoes oxidation to zinc oxide/copper (ZnO/Cu) during carbon dioxide (CO 2 ) hydrogenation to methanol and conclude that the Cu-ZnO interface is the active site for methanol synthesis. Similar experiments conducted two decades ago by Fujitani and Nakamura et al demonstrated that Zn is attached to formate rather than being fully oxidized. Copyright © 2017, American Association for the Advancement of Science.

Efficiency enhancement using a Zn1- x Ge x -O thin film as an n-type window layer in Cu2O-based heterojunction solar cells

NASA Astrophysics Data System (ADS)

Minami, Tadatsugu; Nishi, Yuki; Miyata, Toshihiro

2016-05-01

Efficiency enhancement was achieved in Cu2O-based heterojunction solar cells fabricated with a zinc-germanium-oxide (Zn1- x Ge x -O) thin film as the n-type window layer and a p-type Na-doped Cu2O (Cu2O:Na) sheet prepared by thermally oxidizing Cu sheets. The Ge content (x) dependence of the obtained photovoltaic properties of the heterojunction solar cells is mainly explained by the conduction band discontinuity that results from the electron affinity difference between Zn1- x Ge x -O and Cu2O:Na. The optimal value of x in Zn1- x Ge x -O thin films prepared by pulsed laser deposition was observed to be 0.62. An efficiency of 8.1% was obtained in a MgF2/Al-doped ZnO/Zn0.38Ge0.62-O/Cu2O:Na heterojunction solar cell.

Towards Stable CuZnAl Slurry Catalysts for the Synthesis of Ethanol from Syngas

NASA Astrophysics Data System (ADS)

Dong, Weibing; Gao, Zhihua; Zhang, Qian; Huang, Wei

2018-07-01

A stable CuZnAl slurry catalyst for the synthesis of ethanol from syngas has been developed by adjusting the heat treatment conditions of the complete liquid-phase method. The activity evaluation results showed that the CuZnAl catalyst, when heat-treated under a high pressure and temperature, was a stable catalyst for the synthesis of ethanol. The selectivity of ethanol using the CuZnAl slurry catalyst, which was heat-treated at 553 K under 4.0 MPa, increased continuously with time and was stable at approximately 26.00% after 144 h. The characterization results indicated that the CuZnAl slurry catalyst heat-treated under high pressure conditions could facilitate the formation of a more perfect structure with a larger specific surface area. The prepared catalyst contained a balance of strong and weak acid sites, an appropriate form of Cu2O and a high Cu/Zn atomic ratio at the catalyst surface, providing its stability in ethanol synthesis from syngas.

Room temperature ferromagnetism in Cu doped ZnO

NASA Astrophysics Data System (ADS)

Ali, Nasir; Singh, Budhi; Khan, Zaheer Ahmed; Ghosh, Subhasis

2018-05-01

We report the room temperature ferromagnetism in 2% Cu doped ZnO films grown by RF magnetron sputtering in different argon and oxygen partial pressure. X-ray photoelectron spectroscopy was used to ascertain the oxidation states of Cu in ZnO. The presence of defects within Cu-doped ZnO films can be revealed by electron paramagnetic resonance. It has been observed that saturated magnetic moment increase as we increase the zinc vacancies during deposition.

Effect of Gold Nanoparticles Addition to CuO–ZnO/A₂O₃ Catalyst in Conversion of Carbon Dioxide to Methanol.

PubMed

Kim, Ki-Joong; Ahn, Ho-Geun

2017-04-01

Hydrogenation of carbon dioxide (CO₂) into methanol (CH₃OH) was carried out in the CuO–ZnO based supported gold catalyst prepared by the co-precipitation method. When gold nanoparticles were added to the CuO–ZnO/Al2O₃ catalysts (CuO–ZnO/Au/Al₂O₃), the CO₂ conversion and CH₃OH yield were increased (two times higher than that of CuO–ZnO/Al₂O₃ catalyst) with increasing reaction pressure, but selectivity of CH3OH was decreased. The main reason of this result could suggest the importance gold-oxides interface in CH₃OH formation through hydrogenation of CO₂. Maximum selectivity and yield to CH₃OH over CuO–ZnO/Au/Al₂O₃ were obtained at 250°C and under 15–20 bars.

Effect of Cu-Dopant on the Structural, Magnetic and Electrical Properties of ZnO

NASA Astrophysics Data System (ADS)

Aryanto, D.; Kurniawan, C.; Subhan, A.; Sudiro, T.; Sebayang, P.; Ginting, M.; Siregar, S. M. K.; Nasruddin, M. N.

2017-05-01

Zn1- x Cu x O (x = 0, 2, 3, and 4 at.%) was synthesized by using solid-state reaction technique. The ZnO and CuO powders were mixed and then milled by using high-speed shaker mill. The influence of Cu dopants on the structure, magnetic, and electrical properties was investigated by using XRD, VSM, and I-V and C-V measurements. The XRD analysis showed that the Zn1- x Cu x O had hexagonal wurtzite polycrystalline. The diffraction intensity decreased and the peak position shifted directly to a higher 2θ angle with increasing the dopant concentration. Furthermore, the lattice parameters decreased when the ZnO was doped with x = 0.04, which indicated that the crystal structure changed. The increase of Cu dopants was believed to affect the magnetic and electrical properties of ZnO.

Photoluminescence of vapor and solution grown ZnTe single crystals

NASA Astrophysics Data System (ADS)

Biao, Y.; Azoulay, M.; George, M. A.; Burger, A.; Collins, W. E.; Silberman, E.; Su, C.-H.; Volz, M. E.; Szofran, F. R.; Gillies, D. C.

1994-04-01

ZnTe single crystals grown by horizontal physical vapor transport (PVT) and by vertical traveling heater method (THM) from a Te solution were characterized by photoluminescence (PL) at 10.6 K and by atomic force microscopy (AFM). Copper was identified by PL as a major impurity existing in both crystals, forming a substitutional acceptor, Cu Zn. The THM ZnTe crystals were found to contain more Cu impurity than the PVT ZnTe crystals. The formation of Cu Zn-V Te complexes and the effects of annealing, oxygen contamination and intentional Cu doping were also studied. Finally, the surface morphology analyzed by AFM was correlated to the PL results.

Cyclotron production of {sup 61}Cu using natural Zn and enriched {sup 64}Zn targets

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

Asad, A. H.; Smith, S. V.; Chan, S.

2012-12-19

Copper-61 ({sup 61}Cu) shares with {sup 64}Cu certain advantages for PET diagnostic imaging, but has a shorter half-life (3.4hr vs. 12.7hr) and a greater probability of positron production per disintegration (61% vs. 17.9%). One important application is for in vivo imaging of hypoxic tissue. In this study {sup 61}Cu was produced using the {sup 64}Zn(p,{alpha}){sup 61}Cu reaction on natural Zn or enriched {sup 64}Zn targets. The enriched {sup 64}Zn (99.82%) was electroplated onto high purity gold or silver foils or onto thin Al discs. A typical target bombardment used 30{mu}A; at 11.7, 14.5 or 17.6MeV over 30-60min. The {sup 61}Cumore » (radiochemical purity of >95%) was separated using a combination of cation and anion exchange columns. The {sup 64}Zn target material was recovered after each run, for re-use. In a direct comparison with enriched {sup 64}Zn-target results, {sup 61}Cu production using the cheaper {sup nat}Zn target proved to be an effective alternative.« less

Fibroblast responses and antibacterial activity of Cu and Zn co-doped TiO2 for percutaneous implants

NASA Astrophysics Data System (ADS)

Zhang, Lan; Guo, Jiaqi; Yan, Ting; Han, Yong

2018-03-01

In order to enhance skin integration and antibacterial activity of Ti percutaneous implants, microporous TiO2 coatings co-doped with different doses of Cu2+ and Zn2+ were directly fabricated on Ti via micro-arc oxidation (MAO). The structures of coatings were investigated; the behaviors of fibroblasts (L-929) as well as the response of Staphylococcus aureus (S. aureus) were evaluated. During the MAO process, a large number of micro-arc discharges forming on Ti performed as penetrating channels; O2-, Ca2+, Zn2+, Cu2+ and PO43- delivered via the channels, giving rise to the formation of doped TiO2. Surface characteristics including phase component, topography, surface roughness and wettability were almost the same for different coatings, whereas, the amount of Cu doped in TiO2 decreased with the increased Zn amount. Compared with Cu single-doped TiO2 (0.77 Wt% Cu), the co-doped with appropriate amounts of Cu and Zn, for example, 0.55 Wt% Cu and 2.53 Wt% Zn, further improved proliferation of L-929, facilitated fibroblasts to switch to fibrotic phenotype, and enhanced synthesis of collagen I as well as the extracellular collagen secretion; the antibacterial properties including contact-killing and release-killing were also enhanced. By analyzing the relationship of Cu/Zn amount in TiO2 and the behaviors of L-929 and S. aureus, it can be deduced that when the doped Zn is in a low dose (<1.79 Wt%), the behaviors of L-929 and S. aureus are sensitive to the reduced amount of Cu2+, whereas, Zn2+ plays a key role in accelerating fibroblast functions and reducing S. aureus when its dose obviously increases from 2.63 to 6.47 Wt%.

Potential risks of copper, zinc, and cadmium pollution due to pig manure application in a soil-rice system under intensive farming: a case study of Nanhu, China.

PubMed

Shi, Jiachun; Yu, Xiulin; Zhang, Mingkui; Lu, Shenggao; Wu, Weihong; Wu, Jianjun; Xu, Jianming

2011-01-01

Heavy metal (copper [Cu], zinc [Zn], and cadmium [Cd]) pollution of soils from pig manures in soil-rice ( L.) systems under intensive farming was investigated, taking Nanhu, China, as the case study area. Two hundred pig manures and 154 rice straws, brown rice samples, and corresponding surface soil (0-15 cm) samples were collected in paddy fields from 150 farms in 16 major villages within the study area. The mean Cu and Zn concentrations in pig manures consistently exceeded the related standard. About 44 and 60% of soil samples exceed the Chinese Soil Cu and Cd Environmental Quality Standards, respectively. The concentration of Cu, Zn, and Cd in brown rice did not exceed the Chinese Food Hygiene Standard. There was a significant positive correlation between total Cu and Zn contents in soil and application rate of pig manures. Strong correlation was observed between the extractable Cu, Zn, and Cd in soil and the Cu, Zn, and Cd contents in the brown rice. The spatial distribution maps of Cu and Zn concentrations in brown rice, straw, and extractable soil Cu and Zn concentration also showed similar geographical trends. Further analyses on heavy metals loading flux and accumulation rates from pig manure applied suggested that Cu and Cd contents in soil currently have already exceeded the maximum permissible limit, and Zn, if still at current manure application rates, will reach the ceiling concentration limits in 9 yr. This study assists in understanding the risk of heavy metals accumulating from pig manure applications to agricultural soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Effects of zinc and influence of Acremonium lolii on growth parameters, chlorophyll a fluorescence and antioxidant enzyme activities of ryegrass (Lolium perenne L. cv Apollo).

PubMed

Bonnet, M; Camares, O; Veisseire, P

2000-05-01

The effects of zinc on growth, mineral content, chlorophyll a fluorescence, and detoxifying enzyme activity (ascorbate peroxidase (APX), EC 1.11.1.11; superoxide dismutase (SOD), EC 1.15.1.1) of ryegrass infected or not by Acremonium lolii, and treated with nutrient solution containing 0-50 mM ZnSO(4) were studied. The introduction of zinc induces stress with a decrease in growth at 1, 5 and 10 mM ZnSO(4) and a cessation of growth at 50 mM ZnSO(4), in ryegrass plants infected by A. lolii or not. This decrease in growth may be due to an accumulation of zinc in leaves. Nevertheless, symbiotic plants showed higher values in tiller number, an advantage conferred by the fungus. After 24 d of Zn exposure, leaf fresh weights and leaf water content were lower in plants growing with Zn in the culture medium and no advantage was conferred by the fungus to its host. An increase in Zn supply resulted in a decrease of the Ca, K, Mg, and Cu content of the leaves, a reduction in the quantum yield of electron flow throughout photosystem II (DeltaF/F(1)(m))and a lowering of the efficiency of photosynthetic energy conversion (F(v)/F(m)), compared to control plants. To counter this zinc stress, detoxifying enzymes APX and SOD increased (100%) when Zn reached the value of 50 mM in the nutrient solution. At 10 mM ZnSO(4), the presence of the fungus in the plant led to an increase in the threshold toxicity of plants to zinc by a diminution of APX activity.

Improved Heterojunction Quality in Cu2O-based Solar Cells Through the Optimization of Atmospheric Pressure Spatial Atomic Layer Deposited Zn1-xMgxO

PubMed Central

Ievskaya, Yulia; Hoye, Robert L. Z.; Sadhanala, Aditya; Musselman, Kevin P.; MacManus-Driscoll, Judith L.

2016-01-01

Atmospheric pressure spatial atomic layer deposition (AP-SALD) was used to deposit n-type ZnO and Zn1-xMgxO thin films onto p-type thermally oxidized Cu2O substrates outside vacuum at low temperature. The performance of photovoltaic devices featuring atmospherically fabricated ZnO/Cu2O heterojunction was dependent on the conditions of AP-SALD film deposition, namely, the substrate temperature and deposition time, as well as on the Cu2O substrate exposure to oxidizing agents prior to and during the ZnO deposition. Superficial Cu2O to CuO oxidation was identified as a limiting factor to heterojunction quality due to recombination at the ZnO/Cu2O interface. Optimization of AP-SALD conditions as well as keeping Cu2O away from air and moisture in order to minimize Cu2O surface oxidation led to improved device performance. A three-fold increase in the open-circuit voltage (up to 0.65 V) and a two-fold increase in the short-circuit current density produced solar cells with a record 2.2% power conversion efficiency (PCE). This PCE is the highest reported for a Zn1-xMgxO/Cu2O heterojunction formed outside vacuum, which highlights atmospheric pressure spatial ALD as a promising technique for inexpensive and scalable fabrication of Cu2O-based photovoltaics. PMID:27500923

The effect of Cu/Zn molar ratio on CO{sub 2} hydrogenation over Cu/ZnO/ZrO{sub 2}/Al{sub 2}O{sub 3} catalyst

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

Shaharun, Salina, E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Shaharun, Maizatul S., E-mail: salinashaharun@gmail.com, E-mail: maizats@petronas.com.my; Taha, Mohd F., E-mail: faisalt@petronas.com.my

2014-10-24

Catalytic hydrogenation of carbon dioxide (CO{sub 2}) to methanol is an attractive way to recycle and utilize CO{sub 2}. A series of Cu/ZnO/Al{sub 2}O{sub 3}/ZrO{sub 2} catalysts (CZAZ) containing different molar ratios of Cu/Zn were prepared by the co-precipitation method and investigated in a stirred slurry autoclave system. The catalysts were characterized by temperature-programmed reduction (TPR), field emission scanning electron microscopy-energy dispersive analysis (FESEM-EDX), X-ray diffraction (XRD) and N{sub 2} adsorption-desorption. Higher surface area, SA{sub BET} values (42.6–59.9 m{sup 2}/g) are recorded at low (1) and high (5) Cu/Zn ratios with the minimum value of 35.71 m{sup 2}/g found formore » a Cu/Zn of 3. The reducibility of the metal oxides formed after calcination of catalyst samples was also affected due to change in metal-support interaction. At a low reaction temperature of 443 K, total gas pressure of 3.0 MPa and 0.1 g/mL of the CZAZ catalyst, the selectivity to methanol decreased as the Cu/Zn molar ratio increased, and the maximum selectivity of 67.73 was achieved at Cu/Zn molar ratio of 1. With a reaction time of 3h, the best performing catalyst was CZAZ75 with Cu/Zn molar ratio of 5 giving methanol yield of 79.30%.« less

Anti-cancer efficacy of nonthermal plasma dissolved in a liquid, liquid plasma in heterogeneous cancer cells

NASA Astrophysics Data System (ADS)

Nguyen, Ngoc Hoan; Park, Hyung Jun; Yang, Sang Sik; Choi, Kyeong Sook; Lee, Jong-Soo

2016-07-01

The therapeutic potential of nonthermal plasma for cancer treatment has been reported recently. The heterogeneity of cancer cells need to be addressed to design effective anticancer treatments. Here, we show that treatment with nonthermal atmospheric-pressure plasma dissolved in a liquid (liquid plasma) induces oxidative stress in heterogeneous populations of cancer cells and ultimately kills these cells via apoptosis, regardless of genetic status, e.g., mutations in p53 and other DNA-damage-response genes. We found that liquid plasma markedly increased the concentration of intracellular and mitochondrial reactive oxygen species (ROS), reflecting an influx from the extracellular milieu. Liquid plasma contributed to mitochondrial accumulation of ROS and depolarization of mitochondrial membrane potential with consequent cell death. Healthy normal cells, however, were hardly affected by the liquid-plasma treatment. The antioxidant N-acetylcysteine blocked liquid-plasma-induced cell death. A knockdown of CuZn-superoxide dismutase or Mn-SOD enhanced the plasma-induced cell death, whereas expression of exogenous CuZn-SOD, Mn-SOD, or catalase blocked the cell death. These results suggest that the mitochondrial dysfunction mediated by ROS production is a key contributor to liquid-plasma-induced apoptotic cell death, regardless of genetic variation. Thus, liquid plasma may have clinical applications, e.g., the development of therapeutic strategies and prevention of disease progression despite tumor heterogeneity.

Copper doping of ZnO crystals by transmutation of 64Zn to 65Cu: An electron paramagnetic resonance and gamma spectroscopy study

NASA Astrophysics Data System (ADS)

Recker, M. C.; McClory, J. W.; Holston, M. S.; Golden, E. M.; Giles, N. C.; Halliburton, L. E.

2014-06-01

Transmutation of 64Zn to 65Cu has been observed in a ZnO crystal irradiated with neutrons. The crystal was characterized with electron paramagnetic resonance (EPR) before and after the irradiation and with gamma spectroscopy after the irradiation. Major features in the gamma spectrum of the neutron-irradiated crystal included the primary 1115.5 keV gamma ray from the 65Zn decay and the positron annihilation peak at 511 keV. Their presence confirmed the successful transmutation of 64Zn nuclei to 65Cu. Additional direct evidence for transmutation was obtained from the EPR of Cu2+ ions (where 63Cu and 65Cu hyperfine lines are easily resolved). A spectrum from isolated Cu2+ (3d9) ions acquired after the neutron irradiation showed only hyperfine lines from 65Cu nuclei. The absence of 63Cu lines in this Cu2+ spectrum left no doubt that the observed 65Cu signals were due to transmuted 65Cu nuclei created as a result of the neutron irradiation. Small concentrations of copper, in the form of Cu+-H complexes, were inadvertently present in our as-grown ZnO crystal. These Cu+-H complexes are not affected by the neutron irradiation, but they dissociate when a crystal is heated to 900 °C. This behavior allowed EPR to distinguish between the copper initially in the crystal and the copper subsequently produced by the neutron irradiation. In addition to transmutation, a second major effect of the neutron irradiation was the formation of zinc and oxygen vacancies by displacement. These vacancies were observed with EPR.

Evaluation of structural, morphological and magnetic properties of CuZnNi (CuxZn0.5-xNi0.5Fe2O4) nanocrystalline ferrites for core, switching and MLCI's applications

NASA Astrophysics Data System (ADS)

Akhtar, Majid Niaz; Khan, Muhammad Azhar; Ahmad, Mukhtar; Nazir, M. S.; Imran, M.; Ali, A.; Sattar, A.; Murtaza, G.

2017-01-01

The influence of Cu substitution on the structural and morphological characteristics of Ni-Zn nanocrystalline ferrites have been discussed in this work. The detailed and systematic magnetic characterizations were also done for Cu substituted Ni-Zn nanoferrites. The nanocrystalline ferrites of Cu substituted CuxZn0.5-xNi0.5Fe2O4 ferrites (x=0, 0.1, 0.2, 0.3, 0.4 and 0.5) were synthesized using sol gel self-combustion hybrid method. X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Transmission electron microscope (TEM) and Vibrating sample magnetometer (VSM) were used to investigate the properties of Cu substituted nanocrystalline ferrites. Single phase structure of Cu substituted in Ni-Zn nanocrystalline ferrites were investigated for all the samples. Crystallite size, lattice constant and volume of the cell were found to increase by increasing Cu contents in spinel structure. The better morphology with well-organized nanocrystals of Cu-Zn-Ni ferrites at x=0 and 0.5 were observed from both FESEM and TEM analysis. The average grain size was 35-46 nm for all prepared nanocrystalline samples. Magnetic properties such as coercivity, saturation, remanence, magnetic squareness, magneto crystalline anisotropy constant (K) and Bohr magneton were measured from the recorded M-H loops. The magnetic saturation and remanence were increased by the incorporation of Cu contents. However, coercivity follow the Stoner-Wolforth model except for x=0.3 which may be due to the site occupancy and replacement of Cu contents from octahedral site. The squareness ratio confirmed the super paramgnetic behaviour of the Cu substituted in Ni-Zn nanocrystalline ferrites. Furthermore, Cu substituted Ni-Zn nanocrystalline ferrites may be suitable for many industrial and domestic applications such as components of transformers, core, switching, and MLCI's due to variety of the soft magnetic characteristics.

Effect of fulvic and humic acids on copper and zinc homeostasis in rats.

PubMed

Hullár, István; Vucskits, András Valentin; Berta, Erzsébet; Andrásofszky, Emese; Bersényi, András; Szabó, József

2018-03-01

The objective of this study was to investigate the effects of fulvic acid (FA) and humic acid (HA), the two main compounds of humic substances (HSs), on copper (Cu) and zinc (Zn) homeostasis. Seventy-two male Wistar rats were randomly divided into nine experimental groups. The control diet (AIN-93G formula) and the diets supplemented with 0.1%, 0.2%, 0.4% and 0.8% FA or HA were fed for 26 days. Cu and Zn concentrations of the large intestinal content (LIC), liver, kidney, femur and hair were determined. FA and HA did not influence significantly the Cu or Zn contents of the experimental diets, the rats' feed intake, weight gain and the feed to gain ratio. Both FA and HA decreased the Cu concentrations of the LIC significantly and in a dose-related manner; however the absorption-stimulating effect of HA was more pronounced. FA increased the Cu content of the liver, but neither FA nor HA had a dose-dependent effect on it. FA or HA supplementations had no significant effect on the Cu concentration of the kidney. At the concentrations used, dietary FA or HA supplementations are not promising growth promoters. FA influences the Cu homeostasis unlike HA, because FA not only stimulates Cu absorption, but the extra quantity of absorbed Cu is retained in the organism. The stimulatory effect of HA on Zn absorption may not be manifested in Cu and Zn homeostasis, because of the tight connection of these microelements to FA and HA, which prevents the transmission of Zn from the ZnHA complex to the organs. As regards the effect of FA and HA on Cu and Zn homeostasis, both FA and HA stimulated the absorption of these microelements, but only FA increased the retention of Cu (in the liver) and Zn (in the kidney).

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

PubMed Central

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

2015-01-01

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

Microstructure and mechanical characteristics of gradient structured Cu and Cu alloys processed by surface mechanical attrition treatment

NASA Astrophysics Data System (ADS)

Hu, XZ; Cheng, LP; Chen, HL; Yin, Z.; Zhang, Z.; Shu, BP; Gong, YL; Zhu, XK

2017-05-01

Cu-Al-Zn alloys with different stacking fault energy (SFE) were processed by surface mechanical attrition treatment (SMAT) at cryogenic temperature (CT), mechanical properties of gradient structured Cu-Al-Zn alloys were investigated in this study. Al and Zn content in alloys, which result in the decrease of SFE, can contribute to the increase in strength. Cu-4.5wt%Al-14.3wt%Zn alloy with the lower SFE shows that the strength increased, the ductility did not decrease significantly with increasing processing time, and the strength can be improved by a thicker gradient structure (GS) layer. The better combination of strength and ductility was achieved in Cu-4.5wt%Al-14.3wt%Zn alloy with lower SFE.

Zn and Cu isotopes as tracers of anthropogenic contamination in a sediment core from an urban lake

USGS Publications Warehouse

Thapalia, Anita; Borrok, David M.; Van Metre, Peter C.; Musgrove, MaryLynn; Landa, Edward R.

2010-01-01

In this work, we use stable Zn and Cu isotopes to identify the sources and timing of the deposition of these metals in a sediment core from Lake Ballinger near Seattle, Washington, USA. The base of the Lake Ballinger core predates settlement in the region, while the upper sections record the effects of atmospheric emissions from a nearby smelter and rapid urbanization of the watershed. δ66Zn and δ65Cu varied by 0.50‰ and 0.29‰, respectively, over the 500 year core record. Isotopic changes were correlated with the presmelter period (∼1450 to 1900 with δ66Zn = +0.39‰ ± 0.09‰ and δ65Cu = +0.77‰ ± 0.06‰), period of smelter operation (1900 to 1985 with δ66Zn = +0.14 ± 0.06‰ and δ65Cu = +0.94 ± 0.10‰), and postsmelting/stable urban land use period (post 1985 with δ66Zn = 0.00 ± 0.10‰ and δ65Cu = +0.82‰ ± 0.12‰). Rapid early urbanization during the post World War II era increased metal loading to the lake but did not significantly alter the δ66Zn and δ65Cu, suggesting that increased metal loads during this time were derived mainly from mobilization of historically contaminated soils. Urban sources of Cu and Zn were dominant since the smelter closed in the 1980s, and the δ66Zn measured in tire samples suggests tire wear is a likely source of Zn.

Understanding the Cu-Zn brass alloys using a short-range-order cluster model: significance of specific compositions of industrial alloys

PubMed Central

Hong, H. L.; Wang, Q.; Dong, C.; Liaw, Peter K.

2014-01-01

Metallic alloys show complex chemistries that are not yet understood so far. It has been widely accepted that behind the composition selection lies a short-range-order mechanism for solid solutions. The present paper addresses this fundamental question by examining the face-centered-cubic Cu-Zn α-brasses. A new structural approach, the cluster-plus-glue-atom model, is introduced, which suits specifically for the description of short-range-order structures in disordered systems. Two types of formulas are pointed out, [Zn-Cu12]Zn1~6 and [Zn-Cu12](Zn,Cu)6, which explain the α-brasses listed in the American Society for Testing and Materials (ASTM) specifications. In these formulas, the bracketed parts represent the 1st-neighbor cluster, and each cluster is matched with one to six 2nd-neighbor Zn atoms or with six mixed (Zn,Cu) atoms. Such a cluster-based formulism describes the 1st- and 2nd-neighbor local atomic units where the solute and solvent interactions are ideally satisfied. The Cu-Ni industrial alloys are also explained, thus proving the universality of the cluster-formula approach in understanding the alloy selections. The revelation of the composition formulas for the Cu-(Zn,Ni) industrial alloys points to the common existence of simple composition rules behind seemingly complex chemistries of industrial alloys, thus offering a fundamental and practical method towards composition interpretations of all kinds of alloys. PMID:25399835

Understanding the Cu-Zn brass alloys using a short-range-order cluster model: Significance of specific compositions of industrial alloys

DOE PAGES

Hong, H. L.; Wang, Q.; Dong, C.; ...

2014-11-17

Metallic alloys show complex chemistries that are not yet understood so far. It has been widely accepted that behind the composition selection lies a short-range-order mechanism for solid solutions. The present paper addresses this fundamental question by examining the face-centered-cubic Cu-Zn α-brasses. A new structural approach, the cluster-plus-glue-atom model, is introduced, which suits specifically for the description of short-range-order structures in disordered systems. Two types of formulas are pointed out, [Zn-Cu 12]Zn 1~6 and [Zn-Cu 12](Zn,Cu) 6, which explain the α-brasses listed in the American Society for Testing and Materials (ASTM) specifications. In these formulas, the bracketed parts represent themore » 1 st-neighbor cluster, and each cluster is matched with one to six 2 nd-neighbor Zn atoms or with six mixed (Zn,Cu) atoms. Such a cluster-based formulism describes the 1 st- and 2 nd-neighbor local atomic units where the solute and solvent interactions are ideally satisfied. The Cu-Ni industrial alloys are also explained, thus proving the universality of the cluster-formula approach in understanding the alloy selections. As a result, the revelation of the composition formulas for the Cu-(Zn,Ni) industrial alloys points to the common existence of simple composition rules behind seemingly complex chemistries of industrial alloys, thus offering a fundamental and practical method towards composition interpretations of all kinds of alloys.« less

Controlling superstructural ordering in the clathrate-I Ba 8 M 16 P 30 (M = Cu, Zn) through the formation of metal–metal bonds

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

Dolyniuk, J.; Whitfield, P. S.; Lee, K.

2017-01-01

Order–disorder–order phase transitions in the clathrate-I Ba8Cu16P30 were induced and controlled by aliovalent substitutions of Zn into the framework. Unaltered Ba8Cu16P30 crystallizes in an ordered orthorhombic (Pbcn) clathrate-I superstructure that maintains complete segregation of metal and phosphorus atoms over 23 different crystallographic positions in the clathrate framework. The driving force for the formation of this Pbcn superstructure is the avoidance of Cu–Cu bonds. This superstructure is preserved upon aliovalent substitution of Zn for Cu in Ba8Cu16-xZnxP30 with 0 < x < 1.6 (10% Zn/Mtotal), but vanishes at greater substitution concentrations. Higher Zn concentrations (up to 35% Zn/Mtotal) resulted in themore » additional substitution of Zn for P in Ba8M16+yP30-y (M = Cu, Zn) with 0 ≤ y ≤ 1. This causes the formation of Cu–Zn bonds in the framework, leading to a collapse of the orthorhombic superstructure into the more common cubic subcell of clathrate-I (Pm[3 with combining macron]n). In the resulting cubic phases, each clathrate framework position is jointly occupied by three different elements: Cu, Zn, and P. Detailed structural characterization of the Ba–Cu–Zn–P clathrates-I via single crystal X-ray diffraction, joint synchrotron X-ray and neutron powder diffractions, pair distribution function analysis, electron diffraction and high-resolution electron microscopy, along with elemental analysis, indicates that local ordering is present in the cubic clathrate framework, suggesting the evolution of Cu–Zn bonds. For the compounds with the highest Zn content, a disorder–order transformation is detected due to the formation of another superstructure with trigonal symmetry and Cu–Zn bonds in the clathrate-I framework. It is shown that small changes in the composition, synthesis, and crystal structure have significant impacts on the structural and transport properties of Zn-substituted Ba8Cu16P30.« less

Assessment of the labile fractions of copper and zinc in marinas and port areas in Southern Brazil.

PubMed

Costa, Luiza Dy Fonseca; Wallner-Kersanach, Mônica

2013-08-01

The dissolved labile and labile particulate fractions (LPF) of Cu and Zn were analyzed during different seasons and salinity conditions in estuarine waters of marina, port, and shipyard areas in the southern region of the Patos Lagoon (RS, Brazil). The dissolved labile concentration was determined using the diffusive gradients in thin films technique (DGT). DGT devices were deployed in seven locations of the estuary for 72 h and the physicochemical parameters were also measured. The LPF of Cu and Zn was determined by daily filtering of water samples. Seasonal variation of DGT-Cu concentrations was only significant (p < 0.05) at one shipyard area, while DGT-Zn was significant (p < 0.05) in every locations. The LPF of Cu and Zn concentrations demonstrated seasonal and spatial variability in all locations, mainly at shipyard areas during high salinity conditions. In general, except the control location, the sampling locations showed mean variations of 0.11-0.45 μg L(-1) for DGT-Cu, 0.89-9.96 μg L(-1) for DGT-Zn, 0.65-3.69 μg g(-1) for LPF-Cu, and 1.35-10.87 μg g(-1) for LPF-Zn. Shipyard areas demonstrated the most expressive values of labile Cu and Zn in both fractions. Strong relationship between DGT-Zn and LPF-Zn was found suggesting that the DGT-Zn fraction originates from the suspended particulate matter. Water salinity and suspended particulate matter content indicated their importance for the control of the labile concentrations of Cu and Zn in the water column. These parameters must be taken into consideration for comparison among labile metals in estuaries.

H2 gas sensing properties of a ZnO/CuO and ZnO/CuO/Cu2O Heterostructures

NASA Astrophysics Data System (ADS)

Ababii, N.; Postica, V.; Hoppe, M.; Adelung, R.; Lupan, O.; Railean, S.; Pauporté, T.; Viana, B.

2017-03-01

The most important parameters of gas sensors are sensitivity and especially high selectivity to specific chemical species. To improve these parameters we developed sensor structures based on layered semiconducting oxides, namely CuO/Cu2O, CuO:Zn/Cu2O:Zn, NiO/ZnO. In this work, the ZnO/CuxO (where x = 1, 2) bi-layer heterostructure were grown via a simple synthesis from chemical solution (SCS) at relatively low temperatures (< 95 °C), representing a combination of layered n-type and p-type semiconducting oxides which are widely used as sensing material for gas sensors. The main advantages of the developed device structures are given by simplicity of the synthesis and technological cost-efficiency. Structural investigations showed high crystallinity of synthesized layers confirming the presence of zinc oxide nanostructures on the surface of the copper oxide film deposited on glass substrate. Structural changes in morphology of grown nanostructures induced by post-grown thermal annealing were observed by scanning electron microscopy (SEM) investigations, and were studied in detail. The influence of thermal annealing type on the optical properties was also investigated. As an example of practical applications, the ZnO/CuxO bi-layer heterojunctions and ZnO/CuO/Cu2O three-layered structures were integrated into sensor structures and were tested to different types of reducing gases at different operating temperatures (OPT), showing promising results for fabrication of selective gas sensors.

Electronic Structure and Optical Properties of Cu2ZnGeSe4 : First-Principles Calculations and Vacuum-Ultraviolet Spectroscopic Ellipsometric Studies

NASA Astrophysics Data System (ADS)

Choi, S. G.; Park, J.-S.; Donohue, A. L.; Christensen, S. T.; To, B.; Beall, C.; Wei, S.-H.; Repins, I. L.

2015-11-01

Cu2ZnGeSe4 is of interest for the development of next-generation thin-film photovoltaic technologies. To understand its electronic structure and related fundamental optical properties, we perform first-principles calculations for three structural variations: kesterite, stannite, and primitive-mixed CuAu phases. The calculated data are compared with the room-temperature dielectric function ɛ =ɛ1+i ɛ2 spectrum of polycrystalline Cu2ZnGeSe4 determined by vacuum-ultraviolet spectroscopic ellipsometry in the photon-energy range of 0.7 to 9.0 eV. Ellipsometric data are modeled with the sum of eight Tauc-Lorentz oscillators, and the best-fit model yields the band-gap and Tauc-gap energies of 1.25 and 1.19 eV, respectively. A comparison of overall peak shapes and relative intensities between experimental spectra and the calculated ɛ data for three structural variations suggests that the sample may not have a pure (ordered) kesterite phase. The complex refractive index N =n +i k , normal-incidence reflectivity R , and absorption coefficients α are calculated from the modeled ɛ spectrum, which are also compared with those of Cu2ZnSnSe4 . The spectral features for Cu2ZnGeSe4 appear to be weaker and broader than those for Cu2ZnSnSe4 , which is possibly due to more structural imperfections presented in Cu2ZnGeSe4 than Cu2ZnSnSe4 .

Switching mechanism transition induced by annealing treatment in nonvolatile Cu/ZnO/Cu/ZnO/Pt resistive memory: From carrier trapping/detrapping to electrochemical metallization

NASA Astrophysics Data System (ADS)

Yang, Y. C.; Pan, F.; Zeng, F.; Liu, M.

2009-12-01

ZnO/Cu/ZnO trilayer films sandwiched between Cu and Pt electrodes were prepared for nonvolatile resistive memory applications. These structures show resistance switching under electrical bias both before and after a rapid thermal annealing (RTA) treatment, while it is found that the resistive switching effects in the two cases exhibit distinct characteristics. Compared with the as-fabricated device, the memory cell after RTA demonstrates remarkable device parameter improvements including lower threshold voltages, lower write current, and higher Roff/Ron ratio. A high-voltage forming process is avoided in the annealed device as well. Furthermore, the RTA treatment has triggered a switching mechanism transition from a carrier trapping/detrapping type to an electrochemical-redox-reaction-controlled conductive filament formation/rupture process, as indicated by different features in current-voltage characteristics. Both scanning electron microscopy observations and Auger electron spectroscopy depth profiles reveal that the Cu charge trapping layer in ZnO/Cu/ZnO disperses uniformly into the storage medium after RTA, while x-ray diffraction and x-ray photoelectron spectroscopy analyses demonstrate that the Cu atoms have lost electrons to become Cu2+ ions after dispersion. The above experimental facts indicate that the altered status of Cu in the ZnO/Cu/ZnO trilayer films during RTA treatment should be responsible for the switching mechanism transition. This study is envisioned to open the door for understanding the interrelation between different mechanisms that currently exist in the field of resistive memories.

Fast photocatalytic degradation of sulforhodamine B using ZnO:Cu nanorods

NASA Astrophysics Data System (ADS)

Raji, R.; Gopchandran, K. G.

2018-02-01

In this work, ZnO:Cu nanorods with tunable Cu content were successfully synthesized via co-precipitation method and investigations were made on the use of these nanorods as photocatalyst by observing the photodegradation of a representative dye pollutant of sulforhodamine B (SRB) under sunlight. The X-ray diffraction analysis and high resolution transmission electron microscopy showed that ZnO:Cu nanorods possess wurtzite phase with preferential growth along (101) plane. The formation of additional defect levels in these nanorods on doping with Cu and its dependence on the concentration of Cu were studied using photoluminescence and X-ray photoelectron spectroscopy. ZnO:Cu nanorods results in faster degradation of dye as compared to the undoped ZnO and is found that Cu doping enhances the photodegradation activity significantly and is highly sensitive to Cu doping level. The fast photocatalytic degradation is attributed to the fact that Cu ions promote the interfacial charge transfer and favors the effective charge separation of photogenerated electrons and holes generated during sunlight irradiation, increasing the rate of production of reactive oxygen species needed for the degradation of the dye. The chemical oxygen demand analysis of the dye solution after sunlight irradiation indicates that rate of mineralization is slower than the decoloration. The possible mechanism for degradation of dye under sunlight irradiation is described with a schematic. Additionally, the photostability of the ZnO:Cu nanorods was also tested through three repetitive cycles. This work suggest that the prepared ZnO:Cu nanorods are suitable for cost-effective water purification.

Phytoremediation potential of Miscanthus × giganteus and Spartina pectinata in soil contaminated with heavy metals.

PubMed

Korzeniowska, Jolanta; Stanislawska-Glubiak, Ewa

2015-08-01

The aim of this work was to assess the suitability of Miscanthus × giganteus and Spartina pectinata link to Cu, Ni, and Zn phytoremediation. A 2-year microplot experiment with the tested grasses growing on metal-contaminated soil was carried out. Microplots with cement borders, measuring 1 × 1 × 1m, were filled with Haplic Luvisols soil. Simulated soil contamination with Cu, Ni, and Zn was introduced in the following doses in mg kg(-1): 0-no metals, Cu1-100, Cu2-200, Cu3-400, Ni1-60, Ni2-100, Ni3-240, Zn1-300, Zn2-600, and Zn3-1200. The phytoremediation potential of grasses was evaluated using a tolerance index (TI), bioaccumulation factor (BF), bioconcentration factor (BCF), and translocation factor (TF). S. pectinata showed a higher tolerance to soil contamination with Cu, Ni, and Zn compared to M. × giganteus. S. pectinata was found to have a high suitability for phytostabilization of Zn and lower suitability of Cu and Ni. M. × giganteus had a lower phytostabilization potential than S. pectinata. The suitability of both grasses for Zn phytoextraction depended on the age of the plants. Both grasses were not suitable for Cu and Ni phytoextraction. The research showed that one-season studies were not valuable for fully assessing the phytoremediation potential of perennial plants.

Color tunable light-emitting diodes based on p+-Si/p-CuAlO2/n-ZnO nanorod array heterojunctions

NASA Astrophysics Data System (ADS)

Ling, Bo; Zhao, Jun Liang; Sun, Xiao Wei; Tan, Swee Tiam; Kyaw, Aung Ko Ko; Divayana, Yoga; Dong, Zhi Li

2010-07-01

Wide-range color tuning from red to blue was achieved in phosphor-free p+-Si/p-CuAlO2/n-ZnO nanorod light-emitting diodes at room temperature. CuAlO2 films were deposited on p+-Si substrates by sputtering followed by annealing. ZnO nanorods were further grown on the annealed p+-Si/p-CuAlO2 substrates by vapor phase transport. The color of the p-CuAlO2/n-ZnO nanorod array heterojunction electroluminescence depended on the annealing temperature of the CuAlO2 film. With the increase of the annealing temperature from 900 to 1050 °C, the emission showed a blueshift under the same forward bias. The origin of the blueshift is related to the amount of Cu concentration diffused into ZnO.

Inhibition of growth of S. epidermidis by hydrothermally synthesized ZnO nanoplates

NASA Astrophysics Data System (ADS)

Abinaya, C.; Mayandi, J.; Osborne, J.; Frost, M.; Ekstrum, C.; Pearce, J. M.

2017-07-01

The antibacterial effect of zinc oxide (ZnO#1) as prepared and annealed (ZnO#2) at 400 °C, Cu doped ZnO (CuZnO), and Ag doped ZnO (AgZnO) nanoplates on Staphylococcus epidermidis was investigated for the inhibition and inactivation of cell growth. The results shows that pure ZnO and doped ZnO samples exhibited antibacterial activity against Staphylococcus epidermidis (S. epidermidis) as compared to tryptic soy broth (TSB). Also it is observed that S. epidermidis was extremely sensitive to treatment with ZnO nanoplates and it is clear that the effect is not purely depend on Cu/Ag. Phase identification of a crystalline material and unit cell dimensions were studied by x-ray powder diffraction (XRD). The scanning electron microscopy (SEM) provides information on sample’s surface topography and the EDX confirms the presence of Zn, O, Cu and Ag. X-ray photo-electron spectroscopy (XPS) was used to analyze the elemental composition and electronic state of the elements that exist within the samples. These studies confirms the formation of nanoplates and the presence of Zn, O, Ag, Cu with the oxidation states  +2, -2, 0 and  +2 respectively. These results indicates promising antibacterial applications of these ZnO-based nanoparticles synthesized with low-cost hydrothermal methods.

Serum copper and zinc concentrations in a representative sample of the Canarian population.

PubMed

Díaz Romero, Carlos; Henríquez Sánchez, Patricia; López Blanco, Félix; Rodríguez Rodríguez, Elena; Serra Majem, Lluis

2002-01-01

Serum copper (Cu) and zinc (Zn) concentrations of 395 individuals (187 males + 208 females) living in Canary Islands were determined by flame atomic absorption spectrometry. The mean copper and zinc concentrations were 1.10 +/- 0.25 mg/L and 1.16 +/- 0.52 mg/L respectively. Our data were similar to other data published in other Spanish regions. Individuals from Lanzarote presented a mean Cu and Zn concentrations higher (p < 0.05) than individuals from the rest of islands; Individuals from EL Hierro showed the lowest (p < 0.05) mean Zn concentration. These differences could be attributed a differences in Cu and Zn contents of soil and/or differences in dietary habits of the populations. The mean serum Cu concentration in females was higher (p < 0.05) than in males, however serum Zn concentration did not vary with the sex of the subjects. No relation to socio-economic status and educational level were found with respect to the serum Cu and Zn concentrations. The serum Cu concentration varied with age of individuals, observing the highest (p < 0.05) Cu concentration in the 20-30 year old interval. A higher serum Cu concentration in females within 20-30 year old interval was observed. This could be due to a higher use of oral contraceptives or to the higher number of pregnancies. Boys (younger than 15) showed a decrease (p < 0.05) of the serum Cu concentration with age. The mean Zn concentrations in serum did not change (p > 0.05) among the different age intervals. No clear trends in the serum Cu and Zn concentrations were observed when drinking and smoking habits were considered. The increase of physical exercise reduced (p < 0.05) the serum Cu concentrations.

Study on room temperature gas-sensing performance of CuO film-decorated ordered porous ZnO composite by In2O3 sensitization

PubMed Central

Li, Tian-tian; Bao, Na; Geng, Ai-fang; Yang, Ying; Dong, Xiang-ting

2018-01-01

For the first time, ordered mesoporous ZnO nanoparticles have been synthesized by a template method. The electroplating after chemical plating method was creatively used to form copper film on the surface of the prepared ZnO, and then a CuO film-decorated ordered porous ZnO composite (CuO/ZnO) was obtained by a high-temperature oxidation method. In2O3 was loaded into the prepared CuO film–ZnO by an ultrasonic-assisted method to sensitize the room temperature gas-sensing performance of the prepared CuO/ZnO materials. The doped In2O3 could effectively improve the gas-sensing properties of the prepared materials to nitrogen oxides (NOx) at room temperature. The 1% In2O3 doped CuO/ZnO sample (1 wt% In2O3–CuO/ZnO) showed the best gas-sensing properties whose response to 100 ppm NOx reached 82%, and the detectable minimum concentration reached 1 ppm at room temperature. The prepared materials had a good selectivity, better response, very low detection limit, and high sensitivity to NOx gas at room temperature, which would have a great development space in the gas sensor field and a great research value. PMID:29515887

Zinc and copper in animal feed – development of resistance and co-resistance to antimicrobial agents in bacteria of animal origin

PubMed Central

Yazdankhah, Siamak; Rudi, Knut; Bernhoft, Aksel

2014-01-01

Farmed animals such as pig and poultry receive additional Zn and Cu in their diets due to supplementing elements in compound feed as well as medical remedies. Enteral bacteria in farmed animals are shown to develop resistance to trace elements such as Zn and Cu. Resistance to Zn is often linked with resistance to methicillin in staphylococci, and Zn supplementation to animal feed may increase the proportion of multiresistant E. coli in the gut. Resistance to Cu in bacteria, in particular enterococci, is often associated with resistance to antimicrobial drugs like macrolides and glycopeptides (e.g. vancomycin). Such resistant bacteria may be transferred from the food-producing animals to humans (farmers, veterinarians, and consumers). Data on dose-response relation for Zn/Cu exposure and resistance are lacking; however, it seems more likely that a resistance-driven effect occurs at high trace element exposure than at more basal exposure levels. There is also lack of data which could demonstrate whether Zn/Cu-resistant bacteria may acquire antibiotic resistance genes/become antibiotics resistant, or if antibiotics-resistant bacteria are more capable to become Zn/Cu resistant than antibiotics-susceptible bacteria. Further research is needed to elucidate the link between Zn/Cu and antibiotic resistance in bacteria. PMID:25317117

Tracing contamination sources in soils with Cu and Zn isotopic ratios.

PubMed

Fekiacova, Z; Cornu, S; Pichat, S

2015-06-01

Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are important micronutrients. Human activities contribute to the input of these metals to soils in different chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution. The aim of this paper is to determine whether it is possible to identify (i) Cu and Zn contamination in soils and their sources, on the basis of their isotopic signatures, and (ii) situations that are a priori favorable or not for tracing Cu and Zn pollution using the isotopic approach. Therefore, we compiled data from the literature on Cu and Zn isotopes in soils, rocks and pollutants and added to this database the results of our own research. As only a few studies have dealt with agricultural contamination, we also studied a soil toposequence from Brittany, France, that experienced spreading of pig slurry for tens of years. In the surface horizons of the natural soils, the δ(65)Cu values vary from -0.15 to 0.44‰ and the δ(66)Zn from -0.03 to 0.43‰. Furthermore, vertical variations along soil profiles range from -0.95 to 0.44‰ for δ(65)Cu and from -0.53 to 0.64‰ for δ(66)Zn values. We concluded that pedogenetic processes can produce isotopic fractionation, yet, it is not always discernible and can be overprinted by an exogenous isotopic signature. Furthermore, some contaminants are enriched in heavy Cu or in light Zn compared to the rock or soil, but no generalization can be made. The anthropogenic inputs can be identified based on stable Cu and Zn isotope ratios if the isotope ratios of the sources are different from those of the soil, which needs to be tested for each individual case. Copyright © 2015 Elsevier B.V. All rights reserved.

Electrodeposition of hierarchical ZnO/Cu{sub 2}O nanorod films for highly efficient visible-light-driven photocatalytic applications

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

Ren, S. T.; Fan, G. H.; Liang, M. L.

2014-02-14

The development of high-performance visible-light-responsive photocatalytic materials has attracted widespread interest due to their potential applications in the environmental and energy industries. In this work, hierarchical ZnO nanorods films were successfully prepared on the stainless steel mesh substrates via a simple two-step seed-assisted electrodeposition route. Cu{sub 2}O nanoparticles were then electrodeposited on the surface of ZnO nanorods to form the core-shell heterostructure. The synthesized ZnO/Cu{sub 2}O nanocomposites were characterized by X-ray diffraction, field-emission scanning electron microscopy, and UV-visible spectrophotometer. Due to the branched hierarchical morphologies and core-shell structure, ZnO/Cu{sub 2}O nanomaterials show a prominent visible-light-driven photocatalytic performance under the low-intensitymore » light irradiation (40 mW/cm{sup 2}). The influence of some experimental parameters, such as Cu{sub 2}O loading amount, ZnO morphologies, the substrate type, and the PH of the Cu{sub 2}O precursor solution on ZnO/Cu{sub 2}O photocatalytic performance was evaluated.« less

[Changes in bio-availability of immobilized Cu and Zn bound to phosphate in contaminated soils with different nutrient addition].

PubMed

Xu, Ming-Gang; Zhang, Qian; Sun, Nan; Shen, Hua-Ping; Zhang, Wen-Ju

2009-07-15

Bio-availability of Cu and Zn fixed by phosphate in contaminated soils with application of nutrients were measured by pot experiment. It was simulated for the third national standardization of copper and zinc polluted soils by adding copper and zinc nitrate into red and paddy soils, respectively and together. Phosphate amendment was added to the soils to fix Cu and Zn, then added KCl and NH4Cl or K2SO4 and (NH4)2SO4 fertilizers following to plant Ryegrass, which was harvested after 40 d. Available Cu/Zn content in soils and biomass, Cu/Zn content in the shoot of Ryegrass were determined. Results showed that, compared with no nutrient application, adding KCl and NH4 Cl/K2SO4 and (NH4)2SO4 to polluted red and paddy soils increased the available Cu and Zn content in red soil significantly. The increasing order was KCl and NH4 Cl > K2SO4 and (NH4)2SO4. Especially in single Zn polluted red soil, the available Zn content increased by 133.4% in maximum. Although adding K2SO4 and (NH4)2SO4 could promote the growth of Ryegrass on red soil, and the largest increasing was up to 22.2%, it increased Cu and Zn content in the shoot of Ryegrass for 21.5%-112.6% remarkably. These nutrient effects on available Cu and Zn were not significantly in paddy soil. It was suggested that application of nitrogen and potassium fertilizers to soils could change the bioavailability of Cu/Zn. So it is necessary to take full account of the nutrient influence to the heavy metal stability which fixed by phosphate in contaminated soils when consider contaminated soils remediation by fertilization.

Development of Biodegradable Zinc Oxide Nanowires Targeting Breast Cancer Metastasis

DTIC Science & Technology

2013-09-01

of highly-specificity anti-CD146 monoclonal antibody. 2. Bioconjugation of YY146 to a chelating moiety (NOTA) for the radiolabeling with 64Cu and...vivo investigation of 64Cu -NOTA-ZnO-PEG-TRC105 in 4T1 tumor bearing mice. A serial of coronal PET images about 4T1 tumor-bearing mice at 0.5, 3, 17...and 24 post-injection of 64Cu -NOTA-ZnO-PEG-TRC105, 64Cu -NOTA-ZnO-PEG and TRC105 before 64Cu -NOTA-ZnO-PEG-TRC105 (i.e., blocking). Tumors are

Hindlimb unloading increases oxidative stress and disrupts antioxidant capacity in skeletal muscle

NASA Technical Reports Server (NTRS)

Lawler, John M.; Song, Wook; Demaree, Scott R.; Bloomfield, S. A. (Principal Investigator)

2003-01-01

Skeletal muscle disuse with space-flight and ground-based models (e.g., hindlimb unloading) results in dramatic skeletal muscle atrophy and weakness. Pathological conditions that cause muscle wasting (i.e., heart failure, muscular dystrophy, sepsis, COPD, cancer) are characterized by elevated "oxidative stress," where antioxidant defenses are overwhelmed by oxidant production. However, the existence, cellular mechanisms, and ramifications of oxidative stress in skeletal muscle subjected to hindlimb unloading are poorly understood. Thus we examined the effects of hindlimb unloading on hindlimb muscle antioxidant enzymes (e.g., superoxide dismutase, catalase, glutathione peroxidase), nonenzymatic antioxidant scavenging capacity (ASC), total hydroperoxides, and dichlorohydrofluorescein diacetate (DCFH-DA) oxidation, a direct indicator of oxidative stress. Twelve 6 month old Sprague Dawley rats were divided into two groups: 28 d of hindlimb unloading (n = 6) and controls (n = 6). Hindlimb unloading resulted in a small decrease in Mn-superoxide dismutase activity (10.1%) in the soleus muscle, while Cu,Zn-superoxide dismutase increased 71.2%. In contrast, catalase and glutathione peroxidase, antioxidant enzymes that remove hydroperoxides, were significantly reduced in the soleus with hindlimb unloading by 54.5 and 16.1%, respectively. Hindlimb unloading also significantly reduced ASC. Hindlimb unloading increased soleus lipid hydroperoxide levels by 21.6% and hindlimb muscle DCFH-DA oxidation by 162.1%. These results indicate that hindlimb unloading results in a disruption of antioxidant status, elevation of hydroperoxides, and an increase in oxidative stress.

Photoeletrocatalytic activity of an n-ZnO/p-Cu2O/n-TNA ternary heterojunction electrode for tetracycline degradation.

PubMed

Li, Jinhua; Lv, Shubin; Liu, Yanbiao; Bai, Jing; Zhou, Baoxue; Hu, Xiaofang

2013-11-15

In this study, a novel ternary heterojunction n-ZnO/p-Cu2O/n-TiO2 nanotube arrays (n-ZnO/p-Cu2O/n-TNA) nanophotocatalyst with a sandwich-like nanostructure was constructed and applied for the photoelectrocatalytic (PEC) degradation of typical PPCPs, tetracycline (TC). The ternary heterojunction n-ZnO/p-Cu2O/n-TNA was obtained by depositing Cu2O on the surface of TNA via sonoelectrochemical deposition (SED) and subsequently building a layer of ZnO onto the p-Cu2O/n-TNA surface through hydrothermal synthesis. After being deposited by the Cu2O, the absorption-band edge of the p-Cu2O/n-TNA was obviously red-shifted to the visible region (to 505 nm), and the band gap was reduced from its original 3.20 eV to 2.46 eV. The band gap absorption edge of the ternary n-ZnO/p-Cu2O/n-TNA is similar to that of p-Cu2O/n-TN and extends the visible spectrum absorption to 510 nm, corresponding to an Eg value of about 2.43 eV. Under illumination of visible light, the photocurrent density of the ternary heterojunction n-ZnO/p-Cu2O/n-TNA electrode at 0.5 V (vs. Ag/AgCl) was more than 106 times as high as that of the pure TNAs electrode, 3.6 times as high as that of the binary heterojunction p-Cu2O/n-TNA electrode. The degradation of TC indicated that the ternary heterojunction n-ZnO/p-Cu2O/n-TNA electrode maintained a very high photoelectrocatalytic activity and excellent stability and reliability. Such kind of ternary heterojunction electrode material has a broad application prospect not only in pollution control but also in many other fields. Copyright © 2013 Elsevier B.V. All rights reserved.

Comparative inhalation toxicology of selected materials. Phase 2. Final report, January-July 1986

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

Snipes, M.B.; Bice, D.E.; Burt, D.G.

1988-05-01

Male and female F344/N rats were exposed nose-only to a respirable powder of copper-zinc alloy. No rats died as a result of the exposures. Body weights were reduced relative to sham-exposed rats for rats exposed to 240 and 480 mg. hr Cu-Zn/cu.m week. All of the additional observed biological responses to inhaled Cu-Zn were restricted to the respiratory tract. Lung weights were increased due to an inflammatory response for rats exposed to 120 mg. hr Cu-Zn/cu.m or more per week. Exposure to 240 mg. hr Cu-zn/cu.m per week caused restrictive pulmonary functional disorder, as evidenced by a reduced lung capacity,more » reduced quasi-static compliance, reduced carbon monoxide diffusing capacity, and increased percent forced vital capacity exhaled in 0.1 second. Exposure-related responses in lavage-fluid indicators of lung damage included increased beta-glucuronidase, increased lactate dehydrogenase, and increases in inflammatory cells, total protein, and collagen. Histological lesions produced by Cu-Zn were atrophy of the nasal olfactory epithelium and hyperplasia of goblet cells in the respiratory epithelium, focal necrotizing alveolitis, alveolar macrophage hyperplasia, and goblet cell hyperplasia of bronchial and bronchiolar epithelium. The inhaled Cu-Zn alloy caused exposure-related inflammatory and cytotoxic responses in the respiratory tract, but the inhaled Cu-Zn cleared rapidly and the responses largely resolved after cessation of exposures.« less

(Zn,H)-codoped copper oxide nanoparticles via pulsed laser ablation on Cu-Zn alloy in water

PubMed Central

2012-01-01

Nanosized (5 to 10 nm) amorphous and crystalline nanocondensates, i.e., metallic α-phase of Zn-Cu alloy in face-centered cubic structure and (Zn,H)-codoped cuprite (Cu2O) with high-pressure-favored close-packed sublattice, were formed by pulsed laser ablation on bulk Cu65Zn35 in water and characterized by X-ray/electron diffractions and optical spectroscopy. The as-fabricated hybrid nanocondensates are darkish and showed photoluminescence in the whole visible region. Further dwelling of such nanocondensates in water caused progressive formation of a rice-like assembly of (Zn,H)-codoped tenorite (CuO) nanoparticles with (001), (100), and {111} preferred orientations, (111) tilt boundary, yellowish color, and minimum bandgap narrowing down to ca. 2.7 eV for potential photocatalytic applications. PMID:22647312

Contrasting the material chemistry of Cu 2ZnSnSe 4 and Cu 2ZnSnS (4-x)Se x

DOE PAGES

Aguiar, Jeffery A.; Patel, Maulik; Aoki, Toshihiro; ...

2016-02-02

Earth-abundant sustainable inorganic thin-film solar cells, independent of precious elements, pivot on a marginal material phase space targeting specific compounds. Advanced materials characterization efforts are necessary to expose the roles of microstructure, chemistry, and interfaces. Here, the earth-abundant solar cell device, Cu 2ZnSnS (4-x)Se x, is reported, which shows a high abundance of secondary phases compared to similarly grown Cu 2ZnSnSe 4.

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

PubMed

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

2004-10-08

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

Effect of Zn/Sn molar ratio on the microstructural and optical properties of Cu2Zn1-xSnxS4 thin films prepared by spray pyrolysis technique

NASA Astrophysics Data System (ADS)

Thiruvenkadam, S.; Prabhakaran, S.; Sujay Chakravarty; Ganesan, V.; Vasant Sathe; Santhosh Kumar, M. C.; Leo Rajesh, A.

2018-03-01

Quaternary kesterite Cu2ZnSnS4 (CZTS) compound is one of the most promising semiconductor materials consisting of abundant and eco-friendly elements for absorption layer in thin film solar cells. The effect of Zn/Sn ratio on Cu2Zn1-xSnxS4 (0 ≤ x ≤ 1) thin films were studied by deposited by varying molar volumes in the precursor solution of zinc and tin was carried out in proportion of (1-x) and x respectively onto soda lime glass substrates kept at 573 K by using chemical spray pyrolysis technique. The GIXRD pattern revealed that the films having composites of Cu2ZnSnS4, Cu2SnS3, Sn2S3, CuS and ZnS phases. The crystallinity and grain size were found to increase by increasing the x value and the preferential orientation along (103), (112), (108) and (111) direction corresponding to CZTS, Cu2SnS3, CuS, and ZnS phases respectively. Micro-Raman spectra exposed a prominent peak at 332 cm-1 corresponding to the CZTS phase. Atomic force microscopy was employed to study the grain size and roughness of the deposited thin films. The optical band gap was found to lie between 1.45 and 2.25 eV and average optical absorption coefficient was found to be greater than 105 cm-1. Hall measurements exhibited that all the deposited Cu2Zn1-xSnxS4 films were p type and the resistivity lies between 10.9 ×10-2Ωcm and 149.6 × 10-2Ωcm .

Dual-Analyte Fluorescent Sensor Based on [5]Helicene Derivative with Super Large Stokes Shift for the Selective Determinations of Cu2+ or Zn2+ in Buffer Solutions and Its Application in a Living Cell.

PubMed

Sakunkaewkasem, Siwakorn; Petdum, Anuwut; Panchan, Waraporn; Sirirak, Jitnapa; Charoenpanich, Adisri; Sooksimuang, Thanasat; Wanichacheva, Nantanit

2018-05-10

A new fluorescent sensor, M201-DPA, based on [5]helicene derivative was utilized as dual-analyte sensor for determination of Cu 2+ or Zn 2+ in different media and different emission wavelengths. The sensor could provide selective and bifunctional determination of Cu 2+ in HEPES buffer containing Triton-X100 and Zn 2+ in Tris buffer/methanol without interference from each other and other ions. In HEPES buffer, M201-DPA demonstrated the selective ON-OFF fluorescence quenching at 524 nm toward Cu 2+ . On the other hand, in Tris buffer/methanol, M201-DPA showed the selective OFF-ON fluorescence enhancement upon the addition of Zn 2+ , which was specified by the hypsochromic shift at 448 nm. Additionally, M201-DPA showed extremely large Stokes shifts up to ∼150 nm. By controlling the concentration of Zn 2+ and Cu 2+ in a living cell, the imaging of a HepG2 cellular system was performed, in which the fluorescence of M201-DPA in the blue channel was decreased upon addition of Cu 2+ and was enhanced in UV channel upon addition of Zn 2+ . The detection limits of M201-DPA for Cu 2+ and Zn 2+ in buffer solutions were 5.6 and 3.8 ppb, respectively. Importantly, the Cu 2+ and Zn 2+ detection limits of the developed sensors were significantly lower than permitted Cu 2+ and Zn 2+ concentrations in drinking water as established by the U.S. EPA and WHO.

Potential of Cultivated Ganoderma lucidum Mushrooms for the Production of Supplements Enriched with Essential Elements.

PubMed

Rzymski, Piotr; Mleczek, Mirosław; Niedzielski, Przemysław; Siwulski, Marek; Gąsecka, Monika

2016-03-01

Ganoderma lucidum is an important medicinal mushroom species and there is continuous interest in its bioactive properties. This study evaluated whether it may additionally serve as a nutritional supplement for the trace elements: selenium (Se), copper (Cu), and zinc (Zn). Mushrooms were cultivated on substrates enriched with 0.1 to 0.8 mM of inorganic Se alone or in combination with Zn and/or Cu. Supplementation increased accumulation of the elements in fruiting bodies regardless of the applied cultivation model. G. lucidum demonstrated the ability to accumulate significant amounts of organic Se, maximally amounting to (i) over 44 mg/kg when the substrate was supplemented only with Se, (ii) over 20 mg/kg in the Se+Cu model, (iii) over 25 mg/kg in the Se+Zn model, and (iv) 15 mg/kg in the Se+Cu+Zn model. The accumulation of Cu and Zn steadily increased with their initial substrate concentrations. Maximum concentrations found after supplementation with 0.8 mM amounted to over 55 mg/kg (Se+Zn) and 52 mg/kg (Se+Cu+Zn) of Zn, and 29 mg/kg (Se+Cu) and over 31 mg/kg (Se+Cu+Zn) of Cu. The greater the supplemented concentration and number of supplemented elements, the lower the biomass of G. lucidum fruiting bodies. Nevertheless, it still remained high when the substrate was supplemented up to 0.4 mM with each element. These results highlight that G. lucidum can easily incorporate elements from the substrate and that, when biofortified, its dried fruiting bodies may serve as a nutritional source of these essential elements. © 2016 Institute of Food Technologists®

ZnO/Cu nanocomposite: a platform for direct electrochemistry of enzymes and biosensing applications.

PubMed

Yang, Chi; Xu, Chunxiang; Wang, Xuemei

2012-03-06

Unique structured nanomaterials can facilitate the direct electron transfer between redox proteins and the electrodes. Here, in situ directed growth on an electrode of a ZnO/Cu nanocomposite was prepared by a simple corrosion approach, which enables robust mechanical adhesion and electrical contact between the nanostructured ZnO and the electrodes. This is great help to realize the direct electron transfer between the electrode surface and the redox protein. SEM images demonstrate that the morphology of the ZnO/Cu nanocomposite has a large specific surface area, which is favorable to immobilize the biomolecules and construct biosensors. Using glucose oxidase (GOx) as a model, this ZnO/Cu nanocomposite is employed for immobilization of GOx and the construction of the glucose biosensor. Direct electron transfer of GOx is achieved at ZnO/Cu nanocomposite with a high heterogeneous electron transfer rate constant of 0.67 ± 0.06 s(-1). Such ZnO/Cu nanocomposite provides a good matrix for direct electrochemistry of enzymes and mediator-free enzymatic biosensors.

Glassy behavior of diluted Cu-Zn ferrites

NASA Astrophysics Data System (ADS)

Akhter, Shahida; Hakim, M. A.; Hoque, S. M.; Mathieu, R.; Nordblad, P.

2018-04-01

The magnetic behavior of Zn substituted Cu-Zn spinel ferrites having chemical formula Cu1-xZnxFe2O4 (x = 0.7, 0.8, 0.9 and 1.0) has been studied by SQUID magnetometry, by means of magnetic hysteresis, field-cooled (FC) and zero-field-cooled (ZFC) magnetization, memory effect and low field ac susceptibility measurements. These measurements suggest that the ferrimagnetic phase of the x ≤ 0.8 samples is gradually turned into a spin glass (x ≥ 0.9). The compound with x = 0.9 exhibits the typical dynamical behavior of spin glasses, with indication of aging, rejuvenation and memory effects. The evolution of the magnetic properties of Cu-Zn spinel ferrites with substitution of Zn for Cu is discussed.

Bioaccumulation of Zn, Cu and Mn in the caviar and muscle of Persian sturgeon (Acipenser persicus) from the Caspian Sea, Iran.

PubMed

Mashroofeh, Abdulreza; Bakhtiari, Alireza Riyahi; Pourkazemi, Mohammad

2012-12-01

Concentrations of Zn, Cu and Mn were examined in caviar and muscle of the Persian sturgeon (Acipenser persicus) collected from coastal waters of south Caspian Sea during March and April, 2011. Mean Zn, Cu and Mn concentrations in caviar samples were 21.48, 2.05 and 1.66 μg g(-1) wet weight basis, respectively. The mean Zn, Cu and Mn concentrations in muscle tissues were 7.49, 1.00 and 0.34 μg g(-1) wet weight basis, respectively. The mean concentrations of Zn and Cu in caviar and muscle samples were under the permissible limits proposed by the United Kingdom's Ministry of Agriculture, Fisheries and Food (2000).

Competitive adsorption of heavy metals by extracellular polymeric substances extracted from Klebsiella sp. J1.

PubMed

Yang, Jixian; Wei, Wei; Pi, Shanshan; Ma, Fang; Li, Ang; Wu, Dan; Xing, Jie

2015-11-01

The adsorption of Cu(2+) and Zn(2+) by extracellular polymeric substances (EPS) extracted from Klebsiella sp. J1 and competitive adsorption mechanism were investigated. Equilibrium adsorption capacities of Cu(2+) (1.77mMg(-1)) on Klebsiella sp. J1 EPS were higher than those of Zn(2+) (1.36mMg(-1)) in single systems. The competitive Langmuir and Langmuir-Freundlich isotherm models were proven to be effective in describing the experimental data of binary component system. The three dimensional sorption surfaces of binary component system demonstrated that the presence of Cu(2+) more significantly decreased the sorption of Zn(2+), but the sorption of Cu(2+) was not disturbed by the presence of Zn(2+). FTIR and EEM results revealed the adsorption sites of Cu(2+) entirely overlapped with those of Zn(2+). Cu(2+) and Zn(2+) showed competitive adsorption in binary systems, and Cu(2+) was preferentially adsorbed because of the stronger complexation ability of the protein-like substances in Klebsiella sp. J1 EPS. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thioredoxin-albumin fusion protein prevents copper enhanced zinc-induced neurotoxicity via its antioxidative activity.

PubMed

Tanaka, Ken-Ichiro; Shimoda, Mikako; Chuang, Victor T G; Nishida, Kento; Kawahara, Masahiro; Ishida, Tatsuhiro; Otagiri, Masaki; Maruyama, Toru; Ishima, Yu

2018-01-15

Zinc (Zn) is a co-factor for a vast number of enzymes, and functions as a regulator for immune mechanism and protein synthesis. However, excessive Zn release induced in pathological situations such as stroke or transient global ischemia is toxic. Previously, we demonstrated that the interaction of Zn and copper (Cu) is involved in the pathogenesis of Alzheimer's disease and vascular dementia. Furthermore, oxidative stress has been shown to play a significant role in the pathogenesis of various metal ions induced neuronal death. Thioredoxin-Albumin fusion (HSA-Trx) is a derivative of thioredoxin (Trx), an antioxidative protein, with improved plasma retention and stability of Trx. In this study, we examined the effect of HSA-Trx on Cu 2+ /Zn 2+ -induced neurotoxicity. Firstly, HSA-Trx was found to clearly suppress Cu 2+ /Zn 2+ -induced neuronal cell death in mouse hypothalamic neuronal cells (GT1-7 cells). Moreover, HSA-Trx markedly suppressed Cu 2+ /Zn 2+ -induced ROS production and the expression of oxidative stress related genes, such as heme oxygenase-1. In contrast, HSA-Trx did not affect the intracellular levels of both Cu 2+ and Zn 2+ after Cu 2+ /Zn 2+ treatment. Finally, HSA-Trx was found to significantly suppress endoplasmic reticulum (ER) stress response induced by Cu 2+ /Zn 2+ treatment in a dose dependent manner. These results suggest that HSA-Trx counteracted Cu 2+ /Zn 2+ -induced neurotoxicity by suppressing the production of ROS via interfering the related gene expressions, in addition to the highly possible radical scavenging activity of the fusion protein. Based on these findings, HSA-Trx has great potential as a promising therapeutic agent for the treatment of refractory neurological diseases. Copyright © 2017 Elsevier B.V. All rights reserved.

Comparison of Antibacterial Effects of ZnO and CuO Nanoparticles Coated Brackets against Streptococcus Mutans.

PubMed

Ramazanzadeh, Baratali; Jahanbin, Arezoo; Yaghoubi, Masoud; Shahtahmassbi, Nasser; Ghazvini, Kiarash; Shakeri, Mohammadtaghi; Shafaee, Hooman

2015-09-01

During the orthodontic treatment, microbial plaques may accumulate around the brackets and cause caries, especially in high-risk patients. Finding ways to eliminate this microbial plaque seems to be essential. The aim of this study was to compare the antibacterial effects of nano copper oxide (CuO) and nano zinc oxide (ZnO) coated brackets against Streptococcus mutans (S.mutans) in order to decrease the risk of caries around the orthodontic brackets during the treatment. Sixty brackets were coated with nanoparticles of ZnO (n=20), CuO (n=20) and CuO-ZnO (n=20). Twelve uncoated brackets constituted the control group. The brackets were bonded to the crowns of extracted premolars, sterilized and prepared for antimicrobial tests (S.mutans ATCC35668). The samples taken after 0, 2, 4, 6 and 24 hours were cultured on agar plates. Colonies were counted 24 hours after incubation. One-way ANOVA and Tukey tests were used for statistical analysis. In CuO and CuO-ZnO coated brackets, no colony growth was seen after two hours. Between 0-6 hours, the mean colony counts were not significantly different between the ZnO and the control group (p>0.05). During 6-24 hours, the growth of S.mutans was significantly reduced by ZnO nanoparticles in comparison with the control group (p< 0.001). However, these bacteria were not totally eliminated. CuO and ZnO-CuO nanoparticles coated brackets have better antimicrobial effect on S.mutans than ZnO coated brackets.

Structure flexibility of the Cu2ZnSnS4 absorber in low-cost photovoltaic cells: from the stoichiometric to the copper-poor compounds.

PubMed

Choubrac, L; Lafond, A; Guillot-Deudon, C; Moëlo, Y; Jobic, S

2012-03-19

Here we present for the very first time a single-crystal investigation of the Cu-poor Zn-rich derivative of Cu(2)ZnSnS(4). Nowadays, this composition is considered as the one that delivers the best photovoltaic performances in the specific domain of Cu(2)ZnSnS(4)-based thin-film solar cells. The existence of this nonstoichiometric phase is definitely demonstrated here in an explicit and unequivocal manner on the basis of powder and single-crystal X-ray diffraction analyses coupled with electron microprobe analyses. Crystals are tetragonal, space group I ̅4, Z = 2, with a = 5.43440(15) Å and c = 10.8382(6) Å for Cu(2)ZnSnS(4) and a = 5.43006(5) Å and c = 10.8222(2) Å for Cu(1.71)Zn(1.18)Sn(0.99)S(4). © 2012 American Chemical Society

Functional Performances of CuZnAl Shape Memory Alloy Open-Cell Foams

NASA Astrophysics Data System (ADS)

Biffi, C. A.; Casati, R.; Bassani, P.; Tuissi, A.

2018-01-01

Shape memory alloys (SMAs) with cellular structure offer a unique mixture of thermo-physical-mechanical properties. These characteristics can be tuned by changing the pore size and make the shape memory metallic foams very attractive for developing new devices for structural and functional applications. In this work, CuZnAl SMA foams were produced through the liquid infiltration of space holder method. In comparison, a conventional CuZn brass alloy was foamed trough the same method. Functional performances were studied on both bulk and foamed SMA specimens. Calorimetric response shows similar martensitic transformation (MT) below 0 °C. Compressive response of CuZnAl revealed that mechanical behavior is strongly affected by sample morphology and that damping capacity of metallic foam is increased above the MT temperatures. The shape memory effect was detected in the CuZnAl foams. The conventional brass shows a compressive response similar to that of the martensitic CuZnAl, in which plastic deformation accumulation occurs up to the cellular structure densification after few thermal cycles.

Effects of annealing on the ferromagnetism and photoluminescence of Cu-doped ZnO nanowires.

PubMed

Xu, H J; Zhu, H C; Shan, X D; Liu, Y X; Gao, J Y; Zhang, X Z; Zhang, J M; Wang, P W; Hou, Y M; Yu, D P

2010-01-13

Room temperature ferromagnetic Cu-doped ZnO nanowires have been synthesized using the chemical vapor deposition method. By combining structural characterizations and comparative annealing experiments, it has been found that both extrinsic (CuO nanoparticles) and intrinsic (Zn(1-x)Cu(x)O nanowires) sources are responsible for the observed ferromagnetic ordering of the as-grown samples. As regards the former, annealing in Zn vapor led to a dramatic decrease of the ferromagnetism. For the latter, a reversible switching of the ferromagnetism was observed with sequential annealings in Zn vapor and oxygen ambience respectively, which agreed well with previous reports for Cu-doped ZnO films. In addition, we have for the first time observed low temperature photoluminescence changed with magnetic properties upon annealing in different conditions, which revealed the crucial role played by interstitial zinc in directly mediating high T(c) ferromagnetism and indirectly modulating the Cu-related structured green emission via different charge transfer transitions.

Electronic Structure and Optical Properties of Cu 2ZnGeSe 4. First-Principles Calculations and Vacuum-Ultraviolet Spectroscopic Ellipsometric Studies

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

Choi, Sukgeun; Park, Ji-Sang; Donohue, Andrea

2015-11-19

Cu 2ZnGeSe 4 is of interest for the development of next-generation thin-film photovoltaic technologies. To understand its electronic structure and related fundamental optical properties, we perform first-principles calculations for three structural variations: kesterite, stannite, and primitive-mixed CuAu phases. The calculated data are compared with the room-temperature dielectric functionϵ=ϵ1+iϵ2 spectrum of polycrystalline Cu 2ZnGeSe 4 determined by vacuum-ultraviolet spectroscopic ellipsometry in the photon-energy range of 0.7 to 9.0 eV. Ellipsometric data are modeled with the sum of eight Tauc-Lorentz oscillators, and the best-fit model yields the band-gap and Tauc-gap energies of 1.25 and 1.19 eV, respectively. A comparison of overall peakmore » shapes and relative intensities between experimental spectra and the calculated ϵ data for three structural variations suggests that the sample may not have a pure (ordered) kesterite phase. We found that the complex refractive index N=n+ik, normal-incidence reflectivity R, and absorption coefficients α are calculated from the modeled ϵ spectrum, which are also compared with those of Cu 2ZnSnSe 4 . The spectral features for Cu 2ZnGeSe 4 appear to be weaker and broader than those for Cu 2ZnSnSe 4 , which is possibly due to more structural imperfections presented in Cu 2ZnGeSe 4 than Cu 2ZnSnSe 4 .« less

New production cross sections for the theranostic radionuclide 67Cu

NASA Astrophysics Data System (ADS)

Pupillo, Gaia; Sounalet, Thomas; Michel, Nathalie; Mou, Liliana; Esposito, Juan; Haddad, Férid

2018-01-01

The cross sections of the 68Zn(p,2p)67Cu, 68Zn(p,2n)67Ga and 68Zn(p,3n)66Ga reactions were measured at the ARRONAX facility by using the 70 MeV cyclotron, with particular attention to the production of the theranostic radionuclide 67Cu. Enriched 68Zn material was electroplated on silver backing and exposed to a low-intensity proton beam by using the stacked-foils target method. Since 67Cu and 67Ga radionuclides have similar half-lives and same γ-lines (they both decay to 67Zn), a radiochemical process aimed at Cu/Ga separation was mandatory to avoid interferences in γ-spectrometry measurements. A simple chemical procedure having a high separation efficiency (>99%) was developed and monitored during each foil processing, thanks to the tracer isotopes 61Cu and 66Ga. Nuclear cross sections were measured in the energy range 35-70 MeV by using reference reactions recommended by the International Atomic Energy Agency (IAEA) to monitor beam flux. In comparison with literature data a general good agreement on the trend of the nuclear reactions was noted, especially with latest measurements, but slightly lower values were obtained in case of 67Cu. Experimental results of the 68Zn(p,2p)67Cu, 68Zn(p,2n)67Ga and 68Zn(p,3n)66Ga reactions were also compared with the theoretical values estimated by using the software TALYS. The production yield of the theranostic radionuclide 67Cu was estimated considering the results obtained in this work.

Structural and optical studies on antimony and zinc doped CuInS2 thin films

NASA Astrophysics Data System (ADS)

Ben Rabeh, M.; Chaglabou, N.; Kanzari, M.; Rezig, B.

2009-11-01

The influence of Zn and Sb impurities on the structural, optical and electrical properties of CuInS2 thin films on corning 7059 glass substrates was studied. Undoped and Zn or Sb doped CuInS2 thin films were deposited by thermal evaporation method and annealed in vacuum at temperature of 450 ∘C Undoped thin films were grown from CuInS2 powder using resistively heated tungsten boats. Zn species was evaporated from a thermal evaporator all together to the CuInS2 powder and Sb species was mixed in the starting powders. The amount of the Zn or Sb source was determined to be in the range 0-4 wt% molecular weight compared with the CuInS2 alloy source. The films were studied by means of X-ray diffraction (XRD), Optical reflection and transmission and resistance measurements. The films thicknesses were in the range 450-750 nm. All the Zn: CuInS2 and Sb: CuInS2 thin films have relatively high absorption coefficient between 104 cm-1 and 105 cm-1 in the visible and the near-IR spectral range. The bandgap energies are in the range of 1.472-1.589 eV for Zn: CuInS2 samples and 1.396-1.510 eV for the Sb: CuInS2 ones. The type of conductivity of these films was determined by the hot probe method. Furthermore, we found that Zn and Sb-doped CuInS2 thin films exhibit P type conductivity and we predict these species can be considered as suitable candidates for use as acceptor dopants to fabricate CuInS2-based solar cells.

Ba3CuOs2O9 and Ba3ZnOs2O9, a comparative study

NASA Astrophysics Data System (ADS)

Feng, Hai L.; Jansen, Martin

2018-02-01

Polycrystalline samples of Ba3CuOs2O9 and Ba3ZnOs2O9 were synthesized by solid-state reactions. Ba3CuOs2O9 crystallizes in Cmcm, while Ba3ZnOs2O9 adopts the hexagonal space group P63/mmc. Both the crystal structures consist of face-sharing Os-centered octahedra forming dimer-like Os2O9 units, which are interconnected by corner-sharing CuO6, or ZnO6 octahedra, respectively. In Ba3CuOs2O9, the CuO6 octahedra show a characteristic Jahn-Teller distortion. Both, Ba3CuOs2O9 and Ba3ZnOs2O9, are electrically insulating. Magnetic and specific heat measurements confirm that Ba3CuOs2O9 is antiferromagnetically ordered below 47 K. Analysis of the magnetic data indicated that its magnetic properties are dominated by Cu2+ ions. The magnetic susceptibility of Ba3ZnOs2O9 is weakly temperature-dependent with a broad maximum ≈ 280 K, indicating the presence of strong exchange interactions within the Os2O9 dimer. The residual magnetic susceptibility at low temperatures also suggests the presence of appreciable exchange coupling between the dimers.

The chemisorption and reactions of formic acid on Cu films on ZnO (000 overline1)-O

NASA Astrophysics Data System (ADS)

Ludviksson, A.; Zhang, R.; Campbell, Charles T.; Griffiths, K.

1994-06-01

The adsorption and reactions of formic acid (HCOOD : HCOOH = 3:1) on the oxygen-terminated ZnO(0001¯)-O surface and on thin Cu films deposited on the ZnO(0001¯)-O surface have been studied with temperature programmed desorption (TPD) and XPS. Small amounts of formic acid dissociate at defect sites on clean ZnO(0001¯)-O to yield surface formate (HCOO). The acid D(H) from this dissociation does not reappear in TPD, and is lost to the ZnO bulk, as confirmed by nuclear reaction analysis. The surface HCOO decomposes to yield nearly simultaneous CO 2 (37%), CO (63%) and H 2 TPD peaks at 560 K. Substantial amounts of D (˜ 20%) are incorporated in this hydrogen TPD peak resulting from formate decomposition at ZnO defects, indicating that bulk D is readily accessible. Submonolayer and multilayer Cu films that are deposited at 130 K and partially cover the ZnO surface as 2D and 3D islands adsorb formic acid and decompose it into formate and hydrogen much like the Cu(110) surface. The surface formate from the Cu film decomposes at 470-500 K to give primarily CO 2 and H 2, also much like Cu(110), although atom-thin Cu islands also give ˜ 40% CO. Annealed Cu films give formate decomposition peaks at 25-50 K lower in temperature, attributed to thickening and ordering of the Cu islands to form Cu(111)-like sites. The acid D(H) atom from the formic acid is partially lost by hydrogen spillover from the Cu islands into the ZnO substrate, especially for thin Cu films. This effect partially desorbs and is enhanced upon preannealing the Cu layers, due to increased H diffusion rates across the annealed Cu islands, and/or the decrease in island size. Bulk D(H) is slowly removed as D 2, HD and H 2 above 400 K in diffusion-limited desorption, catalyzed by Cu.

Nucleoside-2',3'/3',5'-bis(thio)phosphate antioxidants are also capable of disassembly of amyloid beta42-Zn(ii)/Cu(ii) aggregates via Zn(ii)/Cu(ii)-chelation.

PubMed

Hevroni, Bosmat Levi; Major, Dan Thomas; Dixit, Mudit; Mhashal, Anil Ranu; Das, Susanta; Fischer, Bilha

2016-05-18

Currently, there is an urgent need for biocompatible metal-ion chelators capable of antioxidant activity and disassembly of amyloid beta (Aβ)-aggregates as potential therapeutics for Alzheimer's disease (AD). We recently demonstrated the promising antioxidant activity of adenine/guanine 2',3' or 3',5'-bis(thio)phosphate analogues, 2'-dA/G3'5'PO/S and A2'3'PO/S, and their affinity to Zn(ii)-ions. These findings encouraged us to evaluate them as agents for the dissolution of Aβ42-Zn(ii)/Cu(ii) aggregates. Specifically, we explored their ability to bind Cu(ii)/Zn(ii)-ions, the geometry and stoichiometry of these complexes, Cu(ii)/Zn(ii)-binding-sites and binding mode, and the ability of these analogues to dissolve Aβ42-Zn(ii)/Cu(ii) aggregates, as well as their effect on the secondary structure of those aggregates. Finally, we identified the most promising agents for dissolution of Aβ42-Zn(ii)/Cu(ii) aggregates. Specifically, we observed the formation of a 1 : 1 complex between 2'-dG3'5'PO and Cu(ii), involving O4 ligands. Zn(ii) was coordinated by both thiophosphate groups of 2'-dA3'5'PS and A2'3'PS involving O2S2 ligands in a 1 : 1 stoichiometry. A2'3'PS dissolves Aβ42-Zn(ii) and Aβ42-Cu(ii) aggregates as effectively as, and 2.5-fold more effectively than EDTA, respectively. Furthermore, 2'-dG3'5'PS and A2'3'PS reverted the Aβ42-M(ii) structure, back to that of the free Aβ42. Finally, cryo-TEM and TEM images confirmed the disassembly of Aβ42 and Aβ42-M(ii) aggregates by A2'3'PS. Hence, 2'-dG3'5'PS and A2'3'PS may serve as promising scaffolds for new AD therapeutics, acting as both effective antioxidants and agents for solubilization of Aβ42-Cu(ii)/Zn(ii) aggregates.

Soft x-ray spectroscopy of a complex heterojunction in high-efficiency thin-film photovoltaics: Intermixing and Zn speciation at the Zn(O,S)/Cu(In,Ga)Se 2 interface

DOE PAGES

Mezher, Michelle; Garris, Rebekah; Mansfield, Lorelle M.; ...

2016-11-11

In this study, the chemical structure of the Zn(O,S)/Cu(In,Ga)Se 2 interface in high-efficiency photovoltaic devices is investigated using X-ray photoelectron and Auger electron spectroscopy, as well as soft X-ray emission spectroscopy. We find that the Ga/(Ga+In) ratio at the absorber surface does not change with the formation of the Zn(O,S)/Cu(In,Ga)Se 2 interface. Furthermore, we find evidence for Zn in multiple bonding environments, including ZnS, ZnO, Zn(OH) 2, and ZnSe. We also observe dehydrogenation of the Zn(O,S) buffer layer after Ar+ ion treatment. Similar to high-efficiency CdS/Cu(In,Ga)Se 2 devices, intermixing occurs at the interface, with diffusion of Se into the buffer,more » and the formation of S—In and/or S—Ga bonds at or close to the interface.« less

Tuning Bandgap of p-Type Cu2Zn(Sn, Ge)(S, Se)4 Semiconductor Thin Films via Aqueous Polymer-Assisted Deposition.

PubMed

Yi, Qinghua; Wu, Jiang; Zhao, Jie; Wang, Hao; Hu, Jiapeng; Dai, Xiao; Zou, Guifu

2017-01-18

Bandgap engineering of kesterite Cu 2 Zn(Sn, Ge)(S, Se) 4 with well-controlled stoichiometric composition plays a critical role in sustainable inorganic photovoltaics. Herein, a cost-effective and reproducible aqueous solution-based polymer-assisted deposition approach is developed to grow p-type Cu 2 Zn(Sn, Ge)(S, Se) 4 thin films with tunable bandgap. The bandgap of Cu 2 Zn(Sn, Ge)(S, Se) 4 thin films can be tuned within the range 1.05-1.95 eV using the aqueous polymer-assisted deposition by accurately controlling the elemental compositions. One of the as-grown Cu 2 Zn(Sn, Ge)(S, Se) 4 thin films exhibits a hall coefficient of +137 cm 3 /C. The resistivity, concentration and carrier mobility of the Cu 2 ZnSn(S, Se) 4 thin film are 3.17 ohm·cm, 4.5 × 10 16 cm -3 , and 43 cm 2 /(V·S) at room temperature, respectively. Moreover, the Cu 2 ZnSn(S, Se) 4 thin film when used as an active layer in a solar cell leads to a power conversion efficiency of 3.55%. The facile growth of Cu 2 Zn(Sn, Ge)(S, Se) 4 thin films in an aqueous system, instead of organic solvents, provides great promise as an environmental-friendly platform to fabricate a variety of single/multi metal chalcogenides for the thin film industry and solution-processed photovoltaic devices.

Cooperative cytotoxic activity of Zn and Cu in bovine serum albumin-conjugated ZnS/CuS nano-composites in PC12 cancer cells

NASA Astrophysics Data System (ADS)

Wang, Hua-Jie; Yu, Xue-Hong; Wang, Cai-Feng; Cao, Ying

2013-11-01

Series of self-assembled and mono-dispersed bovine serum albumin (BSA)-conjugated ZnS/CuS nano-composites with different Zn/Cu ratios had been successfully synthesized by a combination method of the biomimetic synthesis and ion-exchange strategy under the gentle conditions. High-resolution transmission electron microscopy observation, Fourier transform infrared spectra and zeta potential analysis demonstrated that BSA-conjugated ZnS/CuS nano-composites with well dispersity had the hierarchical structure and BSA was a key factor to control the morphology and surface electro-negativity of final products. The real-time monitoring by atomic absorption spectroscopy and powder X-ray diffraction revealed that the Zn/Cu ratio of nano-composites could be controlled by adjusting the ion-exchange time. In addition, the metabolic and morphological assays indicated that the metabolic proliferation and spread of rat pheochromocytoma (PC12) cells could be inhibited by nano-composites, with the high anti-cancer activity at a low concentration (4 ppm). What were more important, Zn and Cu in nano-composites exhibited a positive cooperativity at inhibiting cancer cell functions. The microscope observation and biochemical marker analysis clearly revealed that the nano-composites-included lipid peroxidation and disintegration of membrane led to the death of PC12 cells. Summarily, the present study substantiated the potential of BSA-conjugated ZnS/CuS nano-composites as anti-cancer drug.

Influence of trace elements mixture on bacterial diversity and fermentation characteristics of liquid diet fermented with probiotics under air-tight condition.

PubMed

He, Yuyong; Chen, Zhiyu; Liu, Xiaolan; Wang, Chengwei; Lu, Wei

2014-01-01

Cu2+, Zn2+, Fe2+ and I- are often supplemented to the diet of suckling and early weaning piglets, but little information is available regarding the effects of different Cu2+, Zn2+, Fe2+ and I- mixtures on bacteria growth, diversity and fermentation characteristics of fermented liquid diet for piglets. Pyrosequencing was performed to investigate the effect of Cu2+, Zn2+, Fe2+ and I- mixtures on the diversity, growth and fermentation characteristics of bacteria in the liquid diet fermented with Bacillus subtilis and Enterococcus faecalis under air-tight condition. Results showed that the mixtures of Cu2+, Zn2+, Fe2+ and I- at different concentrations promoted Bacillus growth, increased bacterial diversity and lactic acid production and lowered pH to about 5. The importance of Cu2+, Zn2+, Fe2+ and I- is different for Bacillus growth with the order Zn2+> Fe2+>Cu2+> I- in a 21-d fermentation and Cu2+>I->Fe2+>Zn2+ in a 42-d fermentation. Cu2+, Zn2+, Fe2+ and I- is recommended at a level of 150, 60, 150 and 0.6 mg/kg respectively for the production of fermented liquid diet with Bacillus subtilis. The findings improve our understanding of the influence of trace elements on liquid diet fermentation with probiotics and support the proper use of trace elements in the production of fermented liquid diet for piglets.

Point defects in Cu 2 ZnSnSe 4 (CZTSe): Resonant X-ray diffraction study of the low-temperature order/disorder transition: Point defects in Cu 2 ZnSnSe 4 (CZTSe)

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

Schelhas, L. T.; Stone, K. H.; Harvey, S. P.

The interest in Cu2ZnSn(S,Se)4 (CZTS) for photovoltaic applications is motivated by similarities to Cu(In,Ga)Se2 while being comprised of non-toxic and earth abundant elements. However, CZTS suffers from a Voc deficit, where the Voc is much lower than expected based on the band gap, which may be the result of a high concentration of point-defects in the CZTS lattice. Recently, reports have observed a low-temperature order/disorder transition by Raman and optical spectroscopies in CZTS films and is reported to describe the ordering of Cu and Zn atoms in the CZTS crystal structure. To directly determine the level of Cu/Zn ordering, wemore » have used resonant-XRD, a site, and element specific probe of long range order. We used CZTSe films annealed just below and quenched from just above the transition temperature; based on previous work, the Cu and Zn should be ordered and highly disordered, respectively. Our data show that there is some Cu/Zn ordering near the low temperature transition but significantly less than high chemical order expected from Raman. To understand both our resonant-XRD results and the Raman results, we present a structural model that involves antiphase domain boundaries and accommodates the excess Zn within the CZTS lattice.« less

Effect of short term oral cadmium exposure in rats fed low zinc and low copper diets

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

Panemangalore, M.; Lee, C.J.; Wilson, K.

1986-03-05

The effects of 0, 0.15 and 5.0 ppm Cd in drinking water was determined in 10 week old F-344 rats fed either control - C (30 ppm Zn + 5 ppm Cu), low Zn - LZn (5 ppm Zn), low copper - LCu (0.5 ppm Cu) and low Zn + low Cu - LZn + LCu (5 ppm Zn + 0.5 ppm Cu) diets for 8 weeks. All groups gained about 9 g/wk and neither the decrease in dietary Zn and Cu levels or Cd exposure altered wt gain or food intake (14 g/day). Liver Zn levels averaged about 19more » mg/g in all groups and were unaffected by either diet or Cd exposure; but metallothionein (MT) concentration increased from 19..mu..g/g to 40 ..mu..g/g in groups exposed to 5.0 ppm Cd and was lower in rats given LZn and LZn + LCu diet (pless than or equal to0.05). In contrast, kidney Zn levels declined in groups fed LZn + LCu diets, but exposure to Cd maintained Zn levels. Kidney MT concentration fell in response to LZn, LCu and LZn + LCu diets, while exposure to 5.0 ppm Cd elevated MT concentration almost 3 fold, however, LZn and LCu diets decreased the extent of MT induction (pless than or equal to0.05). Kidney Zn levels appear to be more susceptible to modulation by dietary Zn and Cu levels, and oral Cd exposure.« less

Assessment of heavy metal contamination in Hediste diversicolor (O.F. Müller, 1776), Mugil cephalus (Linnaeus, 1758), and surface sediments of Bafa Lake (Eastern Aegean).

PubMed

Aydin-Onen, S; Kucuksezgin, F; Kocak, F; Açik, S

2015-06-01

In the present study, the bioaccumulation of six heavy metals (Cd, Cr, Cu, Hg, Pb, and Zn) in Hediste (Nereis) diversicolor (O.F. Müller, 1776) and also in the muscle and liver of Mugil cephalus (Linnaeus, 1758) collected from seven stations in the Bafa Lake was investigated. Sediment samples were also collected in each site to assess heavy metal levels and to provide additional information on pollution of the lake. The mean concentrations of heavy metals in sediment, H. diversicolor, and muscle and liver of the fish were found to be in the magnitude of Cr>Pb>Zn>Cu>Cd>Hg, Zn>Cu>Cr>Pb>Hg>Cd, Zn>Cu>Pb>Cr >Hg>Cd, and Cu>Zn>Cr>Cd>Pb>Hg, respectively. Hg, Cu, and Zn in H. diversicolor and Hg and Zn in muscle and also Hg, Cd, Cu, and Zn in liver of fish accumulated in a higher degree than in sediment. There was no clear relationship between metal concentrations in sediments, polychaetes, and fish, except Cr. According to international criteria and Turkish regulations, Pb and Zn values in edible muscle of the fish collected from stations S6 and S5 exceeded the food safety limits, respectively. The results of this study suggest that these sentinel species can be considered as good anthropogenic biological indicators for heavy metal pollution along the Bafa Lake.

Effects of zinc addition to a copper-contaminated vineyard soil on sorption of Zn by soil and plant physiological responses.

PubMed

Tiecher, Tadeu L; Ceretta, Carlos A; Tiecher, Tales; Ferreira, Paulo A A; Nicoloso, Fernando T; Soriani, Hilda H; Rossato, Liana V; Mimmo, Tanja; Cesco, Stefano; Lourenzi, Cledimar R; Giachini, Admir J; Brunetto, Gustavo

2016-07-01

The occurrence of high levels of Cu in vineyard soils is often the result of intensive use of fungicides for the preventive control of foliar diseases and can cause toxicity to plants. Nowadays many grape growers in Southern Brazil have replaced Cu-based with Zn-based products. The aim of the study was to evaluate whether the increase in Zn concentration in a soil with high Cu contents can interfere with the dynamics of these elements, and if this increase in Zn may cause toxicity to maize (Zea mays L.). Soil samples were collected in two areas, one in a vineyard with more than 30 years of cultivation and high concentration of Cu and the other on a natural grassland area adjacent to the vineyard. Different doses of Cu and Zn were added to the soil, and the adsorption isotherms were built following the Langmuir's model. In a second experiment, the vineyard soil was spiked with different Zn concentrations (0, 30, 60, 90, 180, and 270mg Zn kg(-1)) in 3kg pots where maize was grown in a greenhouse for 35 days. When Cu and Zn were added together, there was a reduction in the quantities adsorbed, especially for Zn. Zn addition decreased the total plant dry matter and specific leaf mass. Furthermore, with the increase in the activity of catalase, an activation of the antioxidant system was observed. However, the system was not sufficiently effective to reverse the stress levels imposed on soil, especially in plants grown in the highest doses of Zn. At doses higher than 90Znmgkg(-1) in the Cu-contaminated vineyard soil, maize plants were no longer able to activate the protection mechanism and suffered from metal stress, resulting in suppressed dry matter yields due to impaired functioning of the photosynthetic apparatus and changes in the enzymatic activity of plants. Replacement of Cu- by Zn-based fungicides to avoid Cu toxicity has resulted in soil vineyards contaminated with these metals and damaging of plant photosynthetic apparatus and enzyme activity. Copyright © 2016 Elsevier Inc. All rights reserved.

Separation of copper, iron, and zinc from complex aqueous solutions for isotopic measurement

USGS Publications Warehouse

Borrok, D.M.; Wanty, R.B.; Ridley, W.I.; Wolf, R.; Lamothe, P.J.; Adams, M.

2007-01-01

The measurement of Cu, Fe, and Zn isotopes in natural samples may provide valuable information about biogeochemical processes in the environment. However, the widespread application of stable Cu, Fe, and Zn isotope chemistry to natural water systems remains limited by our ability to efficiently separate these trace elements from the greater concentrations of matrix elements. In this study, we present a new method for the isolation of Cu, Fe, and Zn from complex aqueous solutions using a single anion-exchange column with hydrochloric acid media. Using this method we are able to quantitatively separate Cu, Fe, and Zn from each other and from matrix elements in a single column elution. Elution of the elements of interest, as well as all other elements, through the anion-exchange column is a function of the speciation of each element in the various concentrations of HCl. We highlight the column chemistry by comparing our observations with published studies that have investigated the speciation of Cu, Fe, and Zn in chloride solutions. The functionality of the column procedure was tested by measuring Cu, Fe, and Zn isotopes in a variety of stream water samples impacted by acid mine drainage. The accuracy and precision of Zn isotopic measurements was tested by doping Zn-free stream water with the Zn isotopic standard. The reproducibility of the entire column separation process and the overall precision of the isotopic measurements were also evaluated. The isotopic results demonstrate that the Cu, Fe, and Zn column separates from the tested stream waters are of sufficient purity to be analyzed directly using a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS), and that the measurements are fully-reproducible, accurate, and precise. Although limited in scope, these isotopic measurements reveal significant variations in ??65Cu (- 1.41 to + 0.30???), ??56Fe (- 0.56 to + 0.34???), and ??66Zn (0.31 to 0.49???) among samples collected from different abandoned mines within a single watershed. Hence, Cu, Fe, and Zn isotopic measurements may be a powerful tool for fingerprinting specific metal sources and/or examining biogeochemical reactions within fresh water systems.

A simulation study to improve the efficiency of ZnO1-xSx/Cu2ZnSn (Sy, Se1-y)4 solar cells by composition-ratio control

NASA Astrophysics Data System (ADS)

Sharbati, S.; Norouzzadeh, E.; Mohammadi, S.

2018-04-01

This work investigates the impact of the conduction-band offset (CBO) and valence band offset (VBO) on the performance of Zn (O, S)/Cu2ZnSn (S, Se)4 solar cells by numerical simulations. The band gap alignment at the buffer-CZTS layer interface are controlled by the sulfur-to-oxygen and sulfur-to-selenium ratios. The simulation results show that the high sulfur content in the Zn (O, S) layer makes a big offset in the conduction band and high oxygen content in the in the Zn (O, S) layer eventuates in large valence band offset, that descends Cu2ZnSn (S, Se)4 solar cell performance. We established an initial device model based on an experimental device with world record efficiencies of 12.6%. This study shows that most suitable heterojunction for ZnO1-xSx/Cu2ZnSn (Sy, Se1-y)4 solar cells is when sulfur content ranging 19%-50% in the Zn (O, S) and 30%-50% in the CZTSSe. The efficiency of Cu2ZnSn (S, Se)4 solar cells will be achieved to 14.3%.

In situ DRIFTS study of O3 adsorption on CaO, γ-Al2O3, CuO, α-Fe2O3 and ZnO at room temperature for the catalytic ozonation of cinnamaldehyde

NASA Astrophysics Data System (ADS)

Wu, Jianfeng; Su, Tongming; Jiang, Yuexiu; Xie, Xinling; Qin, Zuzeng; Ji, Hongbing

2017-08-01

In situ DRIFTS were conducted to identify adsorbed ozone and/or adsorbed oxygen species on CaO, ZnO, γ-Al2O3, CuO and α-Fe2O3 surfaces at room temperature. Samples were characterized by means of TG, XRD, N2 adsorption-desorption, pyridine-IR, nitrobenzene-IR, chloroform-IR, and CO2-TPD. Pyridine-DRIFTS measurements evidence two kinds of acid sites in all the samples. Nitrobenzene, chloroform-DRIFTS, and CO2-TPD reveal that there are large amounts of medium-strength base sites on all the metal oxides, and only CaO, ZnO, and γ-Al2O3 have strong base sites. And the benzaldehyde selectivity was increased in the same order of the alkalinity of the metal oxides. With weaker sites, ozone molecules form coordinative complexes bound via the terminal oxygen atom, observed by vibrational frequencies at 2095-2122 and 1026-1054 cm-1. The formation of ozonide O3- at 790 cm-1, atomic oxygen at 1317 cm-1, and superoxide O2- at 1124 cm-1 was detected; these species are believed to be intermediates of O3 decomposition on strong acid/base sites. The adsorption of ozone on metal oxides is a weak adsorption, and other gases, such as CO2, will compete with O3 adsorption. The mechanism of cinnamaldehyde ozonation at room temperature over CaO shows that cinnamaldehyde can not only be oxidized into cinnamic acid, but also be further oxidized into benzaldehyde, benzoic acid, maleic anhydride, and ultimately mineralized to CO2 in the presence of O3.

Zn1-xAlxO:Cu2O transparent metal oxide composite thin films by sol gel method

NASA Astrophysics Data System (ADS)

AlHammad, M. S.

2017-05-01

We have synthesized undoped zinc oxide (ZnO) and Cu2O doped Zn1-XAlXO (AZO; Al/Zn = 1.5 at.%) metal oxide films by sol-gel spin coating method. Atomic force microscopy results indicate that the Zn1-xAlxO:Cu2O is are formed form the fibers. The surface morphology of the films is found to depend on the concentration of Cu2O. The optical constants such as band gap, Urbach energy, refractive index, extinction coefficient and dielectric constants of the films were determined. The transmittance spectra shows that all the films are highly transparent. The study revealed that undoped ZnO film has direct bang gap of 3.29 eV and the optical band gap of films is increased with doping content. The hot probe measurements indicate that Zn1-xAlxO:Cu2O transparent metal oxide composite thin films exhibited p-type electrical conductivity.

μSR investigation of a new diluted magnetic semiconductor Li(Zn,Mn,Cu)As with Mn and Cu codoping at the same Zn sites

NASA Astrophysics Data System (ADS)

Guo, S. L.; Zhao, Y.; Man, H. Y.; Ding, C.; Gong, X.; Zhi, G. X.; Fu, L. C.; Gu, Y. L.; Frandsen, B. A.; Liu, L.; Cheung, S. C.; Munsie, T. J.; Wilson, M. N.; Cai, Y. P.; Luke, G. M.; Uemura, Y. J.; Ning, F. L.

2016-09-01

We report the successful synthesis and characterization of a new type I-II-V bulk form diluted magnetic semiconductor (DMS) Li(Zn,Mn,Cu)As, in which charge and spin doping are decoupled via (Cu,Zn) and (Mn,Zn) substitution at the same Zn sites. Ferromagnetic transition temperature up to  ˜33 K has been observed with a coercive field  ˜40 Oe for the 12.5% doping level. μSR measurements confirmed that the magnetic volume fraction reaches nearly 100% at 2 K, and the mechanism responsible for the ferromagnetic interaction in this system is the same as other bulk form DMSs.

First-principles calculations of stability, electronic and elastic properties of the precipitates present in 7055 aluminum alloy

NASA Astrophysics Data System (ADS)

Huang, Cheng; Shao, Hongbang; Ma, Yunlong; Huang, Yuanchun; Xiao, Zhengbing

2018-04-01

The structural stability, electronic structures and elastic properties of the strengthening precipitates, namely Al3Zr, MgZn2, Al2CuMg and Al2Cu, present in 7055 aluminum alloy were investigated by the first-principles calculations based on density functional theory (DFT). The optimized structural parameters are in good agreement with literature values available. It is found that Al3Zr has the strongest alloying ability and structural stability, while for MgZn2, its structural stability is the worst. The calculated electronic results indicate that covalent bonding is the dominant cohesion of Al3Zr, whereas the fractional ionic interactions coexisting with metallic bonding are found in MgZn2, Al2CuMg and Al2Cu. The elastic constants Cij of these precipitates were calculated, and the bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio and universal elastic anisotropy were derived. It is suggested that MgZn2 is ductile, whereas Al3Zr, Al2CuMg and Al2Cu are brittle, and the elastic anisotropies of them increase in the following sequence: Al3Zr

Substitution of Li for Cu in Cu2ZnSnS4: Toward Wide Band Gap Absorbers with Low Cation Disorder for Thin Film Solar Cells.

PubMed

Lafond, A; Guillot-Deudon, C; Vidal, J; Paris, M; La, C; Jobic, S

2017-03-06

The substitution of lithium for copper in Cu 2 ZnSnS 4 (CZTS) has been experimentally and theoretically investigated. Formally, the (Cu 1-x Li x )ZnSnS 4 system exhibits two well-defined solid solutions. Indeed, single crystal structural analyses demonstrate that the low (x < 0.4) and high (x > 0.6) lithium-content compounds adopt the kesterite structure and the wurtz-kesterite structure, respectively. For x between 0.4 and 0.6, the two aforementioned structure types coexist. Moreover, 119 Sn NMR analyses carried out on a (Cu 0.7 Li 0.3 ) 2 ZnSnS 4 sample clearly indicate that lithium replaces copper preferentially on two of the three available 2-fold crystallographic sites commonly occupied by Cu and Zn in disordered kesterite. Furthermore, the observed individual lines in the NMR spectrum suggest that the propensity of Cu and Zn atoms to be randomly distributed over the 2c and 2d crystallographic sites is lowered when lithium is partially substituted for copper. Additionally, the first-principles calculations provide insights into the arrangement of Li atoms as a function of the Cu/Zn disorder and its effect on the structural (lattice parameters) and optical properties of CZTS (band gap evolution). Those calculations agree with the experimental observations and account for the evolutions of the unit cell parameters as well as for the increase of band gap when the Li-content increases. The calculation of the formation enthalpy of point defect unambiguously indicates that Li modifies the Cu/Zn disorder in a manner similar to the change of Cu/Zn disorder induced by Ag alloying. Overall, it was found that Li alloying is a versatile way of tuning the optoelectronic properties of CZTS making it a good candidate as wide band gap materials for the top cells of tandem solar cells.

Piezo-phototronic effect enhanced UV photodetector based on CuI/ZnO double-shell grown on flexible copper microwire.

PubMed

Liu, Jingyu; Zhang, Yang; Liu, Caihong; Peng, Mingzeng; Yu, Aifang; Kou, Jinzong; Liu, Wei; Zhai, Junyi; Liu, Juan

2016-12-01

In this work, we present a facile, low-cost, and effective approach to fabricate the UV photodetector with a CuI/ZnO double-shell nanostructure which was grown on common copper microwire. The enhanced performances of Cu/CuI/ZnO core/double-shell microwire photodetector resulted from the formation of heterojunction. Benefiting from the piezo-phototronic effect, the presentation of piezocharges can lower the barrier height and facilitate the charge transport across heterojunction. The photosensing abilities of the Cu/CuI/ZnO core/double-shell microwire detector are investigated under different UV light densities and strain conditions. We demonstrate the I-V characteristic of the as-prepared core/double-shell device; it is quite sensitive to applied strain, which indicates that the piezo-phototronic effect plays an essential role in facilitating charge carrier transport across the CuI/ZnO heterojunction, then the performance of the device is further boosted under external strain.

Comment on 'The diatomic dication CuZn{sup 2+} in the gas phase' [J. Chem. Phys. 135, 034306 (2011)

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

Fiser, Jiri; Diez, Reinaldo Pis; Franzreb, Klaus

2013-02-21

In this Comment, the density functional theory (DFT) calculations carried out by Diez et al. [J. Chem. Phys. 135, 034306 (2011)] are revised within the framework of the coupled-cluster single double triple method. These more sophisticated calculations allow us to show that the {sup 2}{Sigma}{sup +} electronic ground state of CuZn{sup 2+}, characterized as the metastable ground state by DFT calculations, is a repulsive state instead. The {sup 2}{Delta} and {sup 2}{Pi} metastable states of CuZn{sup 2+}, on the other hand, should be responsible for the formation mechanism of the dication through the near-resonant electron transfer CuZn{sup +}+ Ar{sup +}{yields}more » CuZn{sup 2+}+ Ar reaction.« less

Synthesis and electrochemical performances of LiNiCuZn oxides as anode and cathode catalyst for low temperature solid oxide fuel cell.

PubMed

Jing, Y; Qin, H; Liu, Q; Singh, M; Zhu, B

2012-06-01

Low temperature solid oxide fuel cell (LTSOFC, 300-600 degrees C) is developed with advantages compared to conventional SOFC (800-1000 degrees C). The electrodes with good catalytic activity, high electronic and ionic conductivity are required to achieve high power output. In this work, a LiNiCuZn oxides as anode and cathode catalyst is prepared by slurry method. The structure and morphology of the prepared LiNiCuZn oxides are characterized by X-ray diffraction and field emission scanning electron microscopy. The LiNiCuZn oxides prepared by slurry method are nano Li0.28Ni0.72O, ZnO and CuO compound. The nano-crystallites are congregated to form ball-shape particles with diameter of 800-1000 nm. The LiNiCuZn oxides electrodes exhibits high ion conductivity and low polarization resistance to hydrogen oxidation reaction and oxygen reduction reaction at low temperature. The LTSOFC using the LiNiCuZn oxides electrodes demonstrates good cell performance of 1000 mW cm(-2) when it operates at 470 degrees C. It is considered that nano-composite would be an effective way to develop catalyst for LTSOFC.

Oral treatment with Cu(II)(atsm) increases mutant SOD1 in vivo but protects motor neurons and improves the phenotype of a transgenic mouse model of amyotrophic lateral sclerosis.

PubMed

Roberts, Blaine R; Lim, Nastasia K H; McAllum, Erin J; Donnelly, Paul S; Hare, Dominic J; Doble, Philip A; Turner, Bradley J; Price, Katherine A; Lim, Sin Chun; Paterson, Brett M; Hickey, James L; Rhoads, Timothy W; Williams, Jared R; Kanninen, Katja M; Hung, Lin W; Liddell, Jeffrey R; Grubman, Alexandra; Monty, Jean-Francois; Llanos, Roxana M; Kramer, David R; Mercer, Julian F B; Bush, Ashley I; Masters, Colin L; Duce, James A; Li, Qiao-Xin; Beckman, Joseph S; Barnham, Kevin J; White, Anthony R; Crouch, Peter J

2014-06-04

Mutations in the metallo-protein Cu/Zn-superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS) in humans and an expression level-dependent phenotype in transgenic rodents. We show that oral treatment with the therapeutic agent diacetyl-bis(4-methylthiosemicarbazonato)copper(II) [Cu(II)(atsm)] increased the concentration of mutant SOD1 (SOD1G37R) in ALS model mice, but paradoxically improved locomotor function and survival of the mice. To determine why the mice with increased levels of mutant SOD1 had an improved phenotype, we analyzed tissues by mass spectrometry. These analyses revealed most SOD1 in the spinal cord tissue of the SOD1G37R mice was Cu deficient. Treating with Cu(II)(atsm) decreased the pool of Cu-deficient SOD1 and increased the pool of fully metallated (holo) SOD1. Tracking isotopically enriched (65)Cu(II)(atsm) confirmed the increase in holo-SOD1 involved transfer of Cu from Cu(II)(atsm) to SOD1, suggesting the improved locomotor function and survival of the Cu(II)(atsm)-treated SOD1G37R mice involved, at least in part, the ability of the compound to improve the Cu content of the mutant SOD1. This was supported by improved survival of SOD1G37R mice that expressed the human gene for the Cu uptake protein CTR1. Improving the metal content of mutant SOD1 in vivo with Cu(II)(atsm) did not decrease levels of misfolded SOD1. These outcomes indicate the metal content of SOD1 may be a greater determinant of the toxicity of the protein in mutant SOD1-associated forms of ALS than the mutations themselves. Improving the metal content of SOD1 therefore represents a valid therapeutic strategy for treating ALS caused by SOD1. Copyright © 2014 the authors 0270-6474/14/348021-11$15.00/0.

Background subtraction for fluorescence EXAFS data of a very dilute dopant Z in Z + 1 host.

PubMed

Medling, Scott; Bridges, Frank

2011-07-01

When conducting EXAFS at the Cu K-edge for ZnS:Cu with very low Cu concentration (<0.04% Cu), a large background was present that increased with energy. This background arises from a Zn X-ray Raman peak, which moves through the Cu fluorescence window, plus the tail of the Zn fluorescence peak. This large background distorts the EXAFS and must be removed separately before reducing the data. A simple means to remove this background is described.

Deep donor state of the copper acceptor as a source of green luminescence in ZnO

NASA Astrophysics Data System (ADS)

Lyons, J. L.; Alkauskas, A.; Janotti, A.; Van de Walle, C. G.

2017-07-01

Copper impurities have long been linked with green luminescence (GL) in ZnO. Copper is known to introduce an acceptor level close to the conduction band of ZnO, and the GL has conventionally been attributed to transitions involving an excited state which localizes holes on neighboring oxygen atoms. To date, a theoretical description of the optical properties of such deep centers has been difficult to achieve due to the limitations of functionals in the density functional theory. Here, we employ a screened hybrid density functional to calculate the properties of Cu in ZnO. In agreement with the experiment, we find that CuZn features an acceptor level near the conduction band of ZnO. However, we find that CuZn also gives rise to a deep donor level 0.46 eV above the valence band of ZnO; the calculated optical transitions involving this state agree well with the GL observed in ZnO:Cu.

Thermal and Microstructure Characterization of Zn-Al-Si Alloys and Chemical Reaction with Cu Substrate During Spreading

NASA Astrophysics Data System (ADS)

Berent, Katarzyna; Pstruś, Janusz; Gancarz, Tomasz

2016-08-01

The problems associated with the corrosion of aluminum connections, the low mechanical properties of Al/Cu connections, and the introduction of EU directives have forced the potential of new materials to be investigated. Alloys based on eutectic Zn-Al are proposed, because they have a higher melting temperature (381 °C), good corrosion resistance, and high mechanical strength. The Zn-Al-Si cast alloys were characterized using differential scanning calorimetry (DSC) measurements, which were performed to determine the melting temperatures of the alloys. Thermal linear expansion and electrical resistivity measurements were performed at temperature ranges of -50 to 250 °C and 25 to 300 °C, respectively. The addition of Si to eutectic Zn-Al alloys not only limits the growth of phases at the interface of liquid solder and Cu substrate but also raises the mechanical properties of the solder. Spreading test on Cu substrate using eutectic Zn-Al alloys with 0.5, 1.0, 3.0, and 5.0 wt.% of Si was studied using the sessile drop method in the presence of QJ201 flux. Spreading tests were performed with contact times of 1, 8, 15, 30, and 60 min, and at temperatures of 475, 500, 525, and 550 °C. After cleaning the flux residue from solidified samples, the spreadability of Zn-Al-Si on Cu was determined. Selected, solidified solder/substrate couples were cross-sectioned, and the interfacial microstructures were studied using scanning electron microscopy and energy dispersive x-ray spectroscopy. The growth of the intermetallic phase layer was studied at the solder/substrate interface, and the activation energy of growth of Cu5Zn8, CuZn4, and CuZn phases were determined.

Electrical and impedance spectroscopy analysis of sol-gel derived spin coated Cu2ZnSnS4 solar cell

NASA Astrophysics Data System (ADS)

Gupta, Goutam Kumar; Garg, Ashish; Dixit, Ambesh

2018-01-01

We carried out electrical and impedance studies on solution derived Al:ZnO/ZnO/CdS/Cu2ZnSnS4/Mo/Glass multilayered solar cell structures to understand their impact on photovoltaic performance. The Cu2ZnSnS4 layer is synthesized on a molybdenum (Mo) coated soda lime glass substrate as an absorber and characterized intensively to optimize the absorber physical properties. The optimized Cu2ZnSnS4 is p-type with 5.8 × 1017 cm-3 hole carrier concentration. The depletion width of the junction is around 20.5 nm and the diffusion capacitance is ˜35.5 nF for these devices. We observed relatively large minority carrier life time ˜23 μs for these structures using open voltage decay analysis. The measured Cu2ZnSnS4/MoS2 and Cu2ZnSnS4/CdS interface resistances are 7.6 kΩ and 12.5 kΩ, respectively. The spatial inhomogeneities are considered and the corresponding resistance is ˜11.4 kΩ. The impedance measurements suggest that in conjunction with series resistance ˜350 Ω, the interface and spatial inhomogeneity resistances also give a significant contribution to the photovoltaic performance.

The single-crystal multinary compound Cu2ZnSnS4 as an environmentally friendly high-performance thermoelectric material

NASA Astrophysics Data System (ADS)

Nagaoka, Akira; Masuda, Taizo; Yasui, Shintaro; Taniyama, Tomoyasu; Nose, Yoshitaro

2018-05-01

We investigated the thermoelectric properties of high-quality p-type Cu2ZnSnS4 single crystals. This material showed two advantages: low thermal conductivity because of lattice scattering caused by the easily formed Cu/Zn disordered structure, and high conductivity because of high doping from changes to the composition. All samples showed a thermal conductivity of 3.0 W m‑1 K‑1 at 300 K, and the Cu-poor sample showed a conductivity of 7.5 S/cm at 300 K because of the high density of shallow-acceptor Cu vacancies. The figure of merit of the Cu-poor Cu2ZnSnS4 reached 0.2 at 400 K, which is 1.4–45 times higher than those of related compounds.

[The evaluation of selected oxidative stress parameters in patients after radioiodine treatment of hyperthyroidism].

PubMed

Owczarek, Tomasz; Kowalczyk, Edward; Poliwczak, Adam Rafał; Bała, Agnieszka; Broncel, Marlena

2012-06-01

Oxidative stress is an important factor of the hyperthyroidism pathogenesis. The radioiodine therapy is an approved treatment method of this common disease and it is connected with exposure to ionizing radiation, which induces increased generation of reactive oxygen species in patient's organism. The aim of the study was to estimate the selected oxidative stress parameters in hyperthyroid patients, initially treated with thiamazole and subsequently with radioiodine. The evaluated parameters were the activity of superoxide dismutase (CuZn-SOD), catalase (CAT) and glutathione peroxidase (GPx) in erythrocytes as well as the level of total antioxidative status (TAS) in plasma. In the study participated 29 healthy volunteers and 27 hyperthyroid patients, treated with thiamazole and prepared for radioiodine therapy. The antioxidant enzymes activity and the level of TAS were measured before administration of radioiodine therapeutic dose (average 18.47 +/- 8.81 mCi) as well as 30 days after treatment and achieving euthyreosis. Hyperthyroid patients prepared with thiamazole for radioiodine therapy demonstrated higher GPx activity (p < 0.0001) and lower TAS level (p < 0.0001) than healthy people. Patients, who become euthyroid after 30 days from radioiodine therapy, were characterised by the increased activity of CAT (p < 0.05) and GPx (p < 0.05) as well as the higher level of TAS (p < 0.05). Patients after radioiodine treatment in comparison to the control group had the same activity of CAT and the level of TAS, although the activity of CuZn-SOD (p < 0.05) and GPx (p < 0.0001) occurred higher than in the control group. Moreover patients with hyperthyroidism before radioiodine treatment showed positive correlation between the level of TSH and TAS, whereas after radioiodine therapy they demonstrated positive correlation between the level of TSH and the activity of CuZn-SOD, CAT and GPx. However, there was no statistically significant correlation between the quantity of administrated radioiodine dose and the value of estimated oxidative stress parameters. The results of the study show the occurrence of oxidative stress in hyperthyroid patients prepared with thiamazole to radioiodine therapy. Euthyreosis achieved by radioiodine treatment effected on normalisation of the activity of CAT and the level of TAS, although the activity of CuZn-SOD and GPx stayed increased. After the analysis of correlation between TSH level, radioiodine dose and measured parameters we can conclude that the intensity of oxidative stress more depends on current thyreometabolic state than on the therapeutic method applied.

Accumulation and chemical fractionation of heavy metals in andisols after a different, 6-year fertilization management.

PubMed

Zhao, Bingzi; Maeda, Morihiro; Zhang, Jiabao; Zhu, Anning; Ozaki, Yasuo

2006-03-01

Andisols are widespread in Japan and have some special properties such as high anion exchange capacity, low bulk density, and high organic matter content, which might influence the accumulation or chemical fractionation of heavy metals. However, few such data exist in Japanese andisols. The primary objective of this study was to investigate the distribution and chemical fractions of Cu, Zn, Ni, and Cr in the soil profiles and subsequently to assess their potential environmental hazard. Soil samples were taken from a field experiment conducted on Japanese andisols, which had received either swine compost or chemical fertilizers for 6 years. Concentrations of Cu, Zn, Ni, and Cr were determined for all of the obtained extract solutions by ICP-AES. Considerably higher total concentrations of Cu and Zn were observed in the top 20 cm layer of the compost-amended soil, relative to the unfertilized soil, while chemical fertilizers had little effect. Application of the swine compost increased the concentrations of Cu and Zn, but not Ni and Cr, in all fractions in the top 20 cm layer. The greatest increase in the organically bound fraction (OM) Cu and dilute acid-exchangeable fraction (DAEXCH) Zn was observed. This suggests that Cu and Zn are potentially bioavailable and mobile in the andisol profiles after 6-year consecutive applications of the swine compost. On the other hand, distribution of Cu, Zn, Ni and Cr among various soil fractions was generally unaffected by chemical fertilizers. We observed that 6-year consecutive applications of the swine compost led to an increase in total metals of Cu and Zn, as well as their all-chemical fractions, in the top 20 cm soil layers. Potential hazard of heavy metals, especially of Cu and Zn, as a result of the use of swine compost on andisols, must be taken into account. The long-term effect of the accumulation of heavy metals, particularly Cu and Zn, in various plant tissues and soils, as well as their potential risk to surface water via runoff and groundwater via leaching, needs to be carefully considered. Further investigations in the long-term experiments are therefore necessary.

Iron Sulfide Attenuates the Methanogenic Toxicity of Elemental Copper and Zinc Oxide Nanoparticles and their Soluble Metal Ion Analogs

PubMed Central

Gonzalez-Estrella, Jorge; Gallagher, Sara; Sierra-Alvarez, Reyes; Field, Jim A.

2016-01-01

Elemental copper (Cu0) and zinc oxide (ZnO) nanoparticle (NP) toxicity to methanogens has been attributed to the release of soluble metal ions. Iron sulfide (FeS) partially controls the soluble concentration of heavy metals and their toxicity in aquatic environments. Heavy metals displace the Fe from FeS forming poorly soluble metal sulfides in the FeS matrix. Therefore, FeS may be expected to attenuate the NP toxicity. This work assessed FeS as an attenuator of the methanogenic toxicity of Cu0 and ZnO NPs and their soluble salt analogs. The toxicity attenuation capacity of fine (25–75 µm) and coarse (500 to 1200 µm) preparations of FeS (FeS-f and FeS-c respectively) was tested in the presence of highly inhibitory concentrations of CuCl2, ZnCl2 Cu0 and ZnO NPs. FeS-f attenuated methanogenic toxicity better than FeS-c. The results revealed that 2.5× less FeS-f than FeS-c was required to recover the methanogenic activity to 50% (activity normalized to uninhibited controls). The results also indicated that a molar FeS-f/Cu0 NP, FeS-f/ZnO NP, FeS-f/ZnCl2, and FeS-f/CuCl2 ratio of 2.14, 2.14, 4.28, and 8.56 respectively, was necessary to recover the methanogenic activity to >75%. Displacement experiments demonstrated that CuCl2 and ZnCl2 partially displaced Fe from FeS. As a whole, the results indicate that not all the sulfide in FeS was readily available to react with the soluble Cu and Zn ions which may explain the need for a large stoichiometric excesses of FeS to highly attenuate Cu and Zn toxicity. Overall, this study provides evidence that FeS attenuates the toxicity caused by Cu0 and ZnO NPs and their soluble ion analogs to methanogens. PMID:26803736

Self-Assembled Formation of Well-Aligned Cu-Te Nano-Rods on Heavily Cu-Doped ZnTe Thin Films

NASA Astrophysics Data System (ADS)

Liang, Jing; Cheng, Man Kit; Lai, Ying Hoi; Wei, Guanglu; Yang, Sean Derman; Wang, Gan; Ho, Sut Kam; Tam, Kam Weng; Sou, Iam Keong

2016-11-01

Cu doping of ZnTe, which is an important semiconductor for various optoelectronic applications, has been successfully achieved previously by several techniques. However, besides its electrical transport characteristics, other physical and chemical properties of heavily Cu-doped ZnTe have not been reported. We found an interesting self-assembled formation of crystalline well-aligned Cu-Te nano-rods near the surface of heavily Cu-doped ZnTe thin films grown via the molecular beam epitaxy technique. A phenomenological growth model is presented based on the observed crystallographic morphology and measured chemical composition of the nano-rods using various imaging and chemical analysis techniques. When substitutional doping reaches its limit, the extra Cu atoms favor an up-migration toward the surface, leading to a one-dimensional surface modulation and formation of Cu-Te nano-rods, which explain unusual observations on the reflection high energy electron diffraction patterns and apparent resistivity of these thin films. This study provides an insight into some unexpected chemical reactions involved in the heavily Cu-doped ZnTe thin films, which may be applied to other material systems that contain a dopant having strong reactivity with the host matrix.

Quantitative analysis of a brass alloy using CF-LIBS and a laser ablation time-of-flight mass spectrometer

NASA Astrophysics Data System (ADS)

Ahmed, Nasar; Abdullah, M.; Ahmed, Rizwan; Piracha, N. K.; Aslam Baig, M.

2018-01-01

We present a quantitative analysis of a brass alloy using laser induced breakdown spectroscopy, energy dispersive x-ray spectroscopy (EDX) and laser ablation time-of-flight mass spectrometry (LA-TOF-MS). The emission lines of copper (Cu I) and zinc (Zn I), and the constituent elements of the brass alloy were used to calculate the plasma parameters. The plasma temperature was calculated from the Boltzmann plot as (10 000  ±  1000) K and the electron number density was determined as (2.0  ±  0.5)  ×  1017 cm-3 from the Stark-broadened Cu I line as well as using the Saha-Boltzmann equation. The elemental composition was deduced using these techniques: the Boltzmann plot method (70% Cu and 30% Zn), internal reference self-absorption correction (63.36% Cu and 36.64% Zn), EDX (61.75% Cu and 38.25% Zn), and LA-TOF (62% Cu and 38% Zn), whereas, the certified composition is (62% Cu and 38% Zn). It was observed that the internal reference self-absorption correction method yields analytical results comparable to that of EDX and LA-TOF-MS.

Cu2O-tipped ZnO nanorods with enhanced photoelectrochemical performance for CO2 photoreduction

NASA Astrophysics Data System (ADS)

Iqbal, Muzaffar; Wang, Yanjie; Hu, Haifeng; He, Meng; Hassan Shah, Aamir; Lin, Lin; Li, Pan; Shao, Kunjuan; Reda Woldu, Abebe; He, Tao

2018-06-01

The design of Cu2O-tipped ZnO nanorods is proposed here aiming at enhanced photoelectrochemical properties. The tip-selective deposition of Cu2O is confirmed by scanning transmission electron microscopy (STEM). The photoinduced charge behavior like charge generation, separation and transport has been thoroughly studied by UV-vis absorption analysis and different photoelectrochemical characterizations, including transient photocurrent, incident photon-to-current efficiency (IPCE), electrochemical impedance spectroscopy (EIS), intensity-modulated photocurrent spectroscopy (IMPS), and Mott-Schottky measurements. The photoelectrochemical characterizations clearly indicate that ZnO/Cu2O structures exhibit much higher performance than pristine ZnO, due to the formation of p-n junction, as well as the tip selective growth of Cu2O on ZnO. Photocatalytic CO2 reduction in aqueous solution under UV-visible light illumination shows that CO is the main product, and with the increase of the Cu2O content in the heterostructure, the CO yield increases. This work shows that Cu2O-tipped ZnO nanorods possess improved behavior of charge generation, separation and transport, which may work as a potential candidate for photocatalytic CO2 reduction.

Periodic table of 3d-metal dimers and their ions.

PubMed

Gutsev, G L; Mochena, M D; Jena, P; Bauschlicher, C W; Partridge, H

2004-10-08

The ground states of the mixed 3d-metal dimers TiV, TiCr, TiMn, TiFe, TiCo, TiNi, TiCu, TiZn, VCr, VMn, VFe, VCo, VNi, VCu, VZn, CrMn, CrFe, CrCo, CrNi, CrCu, CrZn, MnFe, MnCo, MnNi, MnCu, MnZn, FeCo, FeNi, FeCu, FeZn, CoNi, CoCu, CoZn, NiCu, NiZn, and CuZn along with their singly negatively and positively charged ions are assigned based on the results of computations using density functional theory with generalized gradient approximation for the exchange-correlation functional. Except for TiCo and CrMn, our assignment agrees with experiment. Computed spectroscopic constants (r(e),omega(e),D(o)) are in fair agreement with experiment. The ground-state spin multiplicities of all the ions are found to differ from the spin multiplicities of the corresponding neutral parents by +/-1. Except for TiV, MnFe, and MnCu, the number of unpaired electrons, N, in a neutral ground-state dimer is either N(1)+N(2) or mid R:N(1)-N(2)mid R:, where N(1) and N(2) are the numbers of unpaired 3d electrons in the 3d(n)4s(1) occupation of the constituent atoms. Combining the present and previous results obtained at the same level of theory for homonuclear 3d-metal and ScX (X=Ti-Zn) dimers allows one to construct "periodic" tables of all 3d-metal dimers along with their singly charged ions.

Ultrasensitive detection of EGFR gene based on surface plasmon resonance enhanced electrochemiluminescence of CuZnInS quantum dots.

PubMed

Chen, Xueqian; Gui, Wenying; Ma, Qiang

2018-06-07

In our work, a novel DNA electrochemiluminescence (ECL) sensor based on CuZnInS quantum dots (QDs) and gold-nanoparticles (Au NPs) is developed for highly sensitive detection of epidermal growth factor receptor (EGFR) Gene, which has a close relation with the lung cancer. The CuZnInS QDs work as a novel kind of ECL luminophore, whose defect state emission is suitable for ECL sensing. To enhance the sensitivity of the sensing system, Au NPs are utilized creatively to strengthen the ECL intensity of CuZnInS QD S according to the surface plasmon resonance (SPR) effect. An ultrasensitive and universal detecting platform is built based on the SPR effect between Au NPs and CuZnInS QD S . The effect of the capped stabilizer on the ECL signal of QDs is firstly investigated. Three different stabilizers are used to cap the CuZnInS QDs, including mercaptopropionic acid (MPA), l-glutathione (GSH) and cysteamine (CA). MPA capped CuZnInS QDs possess the strongest ECL intensity among the three kinds of the CuZnInS QDs. Under the optimum conditions, a good linear relationship between ECL intensity and the concentration of target DNA is obtained in the range from 0.05 nmol L -1 to 1 nmol L -1 . The detection limit is 0.0043 nmol L -1 . The proposed DNA sensor has been employed for the determination of target DNA EGFR in human serum samples with satisfactory results. Copyright © 2018 Elsevier B.V. All rights reserved.

Accumulation and Toxicity of CuO and ZnO Nanoparticles through Waterborne and Dietary Exposure of Goldfish (Carassius auratus)

PubMed Central

Ates, Mehmet; Arslan, Zikri; Demir, Veysel; Daniels, James; Farah, Ibrahim O.

2014-01-01

Dietary and waterborne exposure to CuO and ZnO nanoparticles (NPs) was conducted using a simplified model of an aquatic food chain consisting of zooplankton (Artemia salina) and goldfish (Carassius auratus) to determine bioaccumulation, toxic effects and particle transport through trophic levels. Artemia contaminated with NPs were used as food in dietary exposure. Fish were exposed to suspensions of the NPs in waterborne exposure. ICP-MS analysis showed that accumulation primarily occurred in the intestine, followed by the gills and liver. Dietary uptake was lower, but was found to be a potential pathway for transport of NPs to higher organisms. Waterborne exposure resulted in about a tenfold higher accumulation in the intestine. The heart, brain and muscle tissue had no significant Cu or Zn. However, concentrations in muscle increased with NP concentration, which was ascribed to bioaccumulation of Cu and Zn released from NPs. Free Cu concentration in the medium was always higher than that of Zn, indicating CuO NPs dissolved more readily. ZnO NPs were relatively benign, even in waterborne exposure (p≥0.05). In contrast, CuO NPs were toxic. Malondialdehyde levels in the liver and gills increased substantially (p<0.05). Despite lower Cu accumulation, the liver exhibited significant oxidative stress, which could be from chronic exposure to Cu ions. PMID:24860999

Accumulation and toxicity of CuO and ZnO nanoparticles through waterborne and dietary exposure of goldfish (Carassius auratus).

PubMed

Ates, Mehmet; Arslan, Zikri; Demir, Veysel; Daniels, James; Farah, Ibrahim O

2015-01-01

Dietary and waterborne exposure to copper oxide (CuO) and zinc oxide (ZnO) nanoparticles (NPs) was conducted using a simplified model of an aquatic food chain consisting of zooplankton (Artemia salina) and goldfish (Carassius auratus) to determine bioaccumulation, toxic effects, and particle transport through trophic levels. Artemia contaminated with NPs were used as food in dietary exposure. Fish were exposed to suspensions of the NPs in waterborne exposure. ICP-MS analysis showed that accumulation primarily occurred in the intestine, followed by the gills and liver. Dietary uptake was lower, but was found to be a potential pathway for transport of NPs to higher organisms. Waterborne exposure resulted in about a 10-fold higher accumulation in the intestine. The heart, brain, and muscle tissue had no significant Cu or Zn. However, concentrations in muscle increased with NP concentration, which was ascribed to bioaccumulation of Cu and Zn released from NPs. Free Cu concentration in the medium was always higher than that of Zn, indicating CuO NPs dissolved more readily. ZnO NPs were relatively benign, even in waterborne exposure (p ≥ 0.05). In contrast, CuO NPs were toxic. Malondialdehyde levels in the liver and gills increased substantially (p < 0.05). Despite lower Cu accumulation, the liver exhibited significant oxidative stress, which could be from chronic exposure to Cu ions. © 2014 Wiley Periodicals, Inc.

Catalytic conversion of syngas to mixed alcohols over Zn-Mn promoted Cu-Fe based catalyst

DOE PAGES

Lu, Yongwu; Yu, Fei; Hu, Jin; ...

2012-04-12

Zn-Mn promoted Cu-Fe based catalyst was synthesized by the co-precipitation method. Mixed alcohols synthesis from syngas was studied in a half-inch tubular reactor system after the catalyst was reduced. Zn-Mn promoted Cu-Fe based catalyst was characterized by SEM-EDS, TEM, XRD, and XPS. The liquid phase products (alcohol phase and hydrocarbon phase) were analyzed by GC-MS and the gas phase products were analyzed by GC. The results showed that Zn-Mn promoted Cu-Fe based catalyst had high catalytic activity and high alcohol selectivity. The maximal CO conversion rate was 72%, and the yield of alcohol and hydrocarbons were also very high. Cumore » (111) was the active site for mixed alcohols synthesis, Fe 2C (101) was the active site for olefin and paraffin synthesis. The reaction mechanism of mixed alcohols synthesis from syngas over Zn-Mn promoted Cu-Fe based catalyst was proposed. Here, Zn-Mn promoted Cu-Fe based catalyst can be regarded as a potential candidate for catalytic conversion of biomass-derived syngas to mixed alcohols.« less

Analysis of heavy metals concentration in water and sediment in the Hara biosphere reserve, southern Iran.

PubMed

Nowrouzi, Mohsen; Mansouri, Borhan; Nabizadeh, Sahar; Pourkhabbaz, Alireza

2014-02-01

This study determined the concentration of heavy metals (Al, Cr, Cu, and Zn) in water and sediments at nine sites in the Hara biosphere reserve of southern Iran during the summer and winter 2010. Determination of Al, Cr, Cu, and Zn in water was carried out by graphite furnace atomic absorption spectrometer (Shimadzu, AA 610s) and in sediment by flame atomic absorption spectrometer (Perkin Elmer, AA3030). Results showed that the heavy metal concentrations in the water samples decreased in the sequence of Zn > Al > Cu > Cr, while in sediment samples were Cr > Zn > Cu > Al. Data analysis indicated that with the exception of Al, there was a Pearson's correlation coefficient between pH and Cu, Zn, and Cr at α = 0.01, 0.05, and 0.001 in sediment (in winter), respectively. There were also significant differences between heavy metals of Cr, Cu, and Zn during the two seasons (p < 0.001) in the water and sediment.

Temporal Variation and Ecological Risk Assessment of Metals in Soil Nearby a Pb⁻Zn Mine in Southern China.

PubMed

Cao, Congcong; Wang, Li; Li, Hairong; Wei, Binggan; Yang, Linsheng

2018-05-09

Metal contamination in soil from tailings induces risks for the ecosystem and for humans. In this study, the concentrations and ecological risks of Cd, Cu, Pb, and Zn in soil contaminated by a tailing from Yangshuo (YS) lead and zinc (Pb⁻Zn) mine, which collapsed for more than 40 years, were determined in 2015. The mean concentrations of Zn, Pb, Cu, and Cd were 1301.79, 768.41, 82.60, and 4.82 mg/kg, respectively, which, with years of remediation activities, decreased by 66.9%, 61.7%, 65.4%, and 65.3% since 1986, but still exceed the national standards. From 1986 to 2015, soil pH increased significantly, with available concentrations of Zn, Pb, Cu and Cd decreasing by 13%, 81%, 77%, and 67%, respectively, and potential ecological risk indexes ( E r ) of the determined metals decreasing by more than 60%. Horizontally, total contents and percentages of available concentrations of Zn, Pb, Cu, and Cd decreased with the distance from the tailing heap in SD village, while pH values showed the reverse pattern. Vertically, Zn and Cd, Pb, and Cu showed similar vertical distribution patterns in the soil profiles. There was a slight downward migration for the determined metals in soil of M and H area and the mobility was in the order of Cd > Zn > Pb > Cu. It can be concluded that although concentrations and ecological risks of Cd, Cu, Pb, and Zn in soil decreased significantly, SD village is still a high risk area, and the priority pollutant is Cd.

Temporal Variation and Ecological Risk Assessment of Metals in Soil Nearby a Pb–Zn Mine in Southern China

PubMed Central

Cao, Congcong; Wang, Li; Li, Hairong; Wei, Binggan

2018-01-01

Metal contamination in soil from tailings induces risks for the ecosystem and for humans. In this study, the concentrations and ecological risks of Cd, Cu, Pb, and Zn in soil contaminated by a tailing from Yangshuo (YS) lead and zinc (Pb–Zn) mine, which collapsed for more than 40 years, were determined in 2015. The mean concentrations of Zn, Pb, Cu, and Cd were 1301.79, 768.41, 82.60, and 4.82 mg/kg, respectively, which, with years of remediation activities, decreased by 66.9%, 61.7%, 65.4%, and 65.3% since 1986, but still exceed the national standards. From 1986 to 2015, soil pH increased significantly, with available concentrations of Zn, Pb, Cu and Cd decreasing by 13%, 81%, 77%, and 67%, respectively, and potential ecological risk indexes (Er) of the determined metals decreasing by more than 60%. Horizontally, total contents and percentages of available concentrations of Zn, Pb, Cu, and Cd decreased with the distance from the tailing heap in SD village, while pH values showed the reverse pattern. Vertically, Zn and Cd, Pb, and Cu showed similar vertical distribution patterns in the soil profiles. There was a slight downward migration for the determined metals in soil of M and H area and the mobility was in the order of Cd > Zn > Pb > Cu. It can be concluded that although concentrations and ecological risks of Cd, Cu, Pb, and Zn in soil decreased significantly, SD village is still a high risk area, and the priority pollutant is Cd. PMID:29747376

Molecular and biochemical characterization of a unique mutation in CCS, the human copper chaperone to superoxide dismutase.

PubMed

Huppke, Peter; Brendel, Cornelia; Korenke, Georg Christoph; Marquardt, Iris; Donsante, Anthony; Yi, Ling; Hicks, Julia D; Steinbach, Peter J; Wilson, Callum; Elpeleg, Orly; Møller, Lisbeth Birk; Christodoulou, John; Kaler, Stephen G; Gärtner, Jutta

2012-08-01

Copper (Cu) is a trace metal that readily gains and donates electrons, a property that renders it desirable as an enzyme cofactor but dangerous as a source of free radicals. To regulate cellular Cu metabolism, an elaborate system of chaperones and transporters has evolved, although no human Cu chaperone mutations have been described to date. We describe a child from a consanguineous family who inherited homozygous mutations in the SLC33A1, encoding an acetyl CoA transporter, and in CCS, encoding the Cu chaperone for superoxide dismutase. The CCS mutation, p.Arg163Trp, predicts substitution of a highly conserved arginine residue at position 163, with tryptophan in domain II of CCS, which interacts directly with superoxide dismutase 1 (SOD1). Biochemical analyses of the patient's fibroblasts, mammalian cell transfections, immunoprecipitation assays, and Lys7Δ (CCS homolog) yeast complementation support the pathogenicity of the mutation. Expression of CCS was reduced and binding of CCS to SOD1 impaired. As a result, this mutation causes reduced SOD1 activity and may impair other mechanisms important for normal Cu homeostasis. CCS-Arg163Trp represents the primary example of a human mutation in a gene coding for a Cu chaperone. © 2012 Wiley Periodicals, Inc.

Modulation of innate immunity and gene expressions in white shrimp Litopenaeus vannamei following long-term starvation and re-feeding

PubMed Central

Lin, Yong-Chin; Chen, Jiann-Chu; C. Man, Siti Nursafura; W. Morni, Wan Zabidii; N.A. Suhaili, Awangku Shahrir; Cheng, Sha-Yen; Hsu, Chih-Hung

2012-01-01

The survival rate, weight loss, immune parameters, resistance against Vibrio alginolyticus and white-spot syndrome virus (WSSV), and expressions of lipopolysaccharide- and ß-glucan-binding protein (LGBP), peroxinectin (PX), prophenoloxidase-activating enzyme (ppA), prophenoloxidase (proPO) I, proPO II, α2-macroglobulin (α2-M), integrin ß, heat shock protein 70 (HSP70), cytosolic manganese superoxide dismutase (cytMnSOD), mitochondrial manganese superoxide dismutase (mtMnSOD), and extracellular copper and zinc superoxide dismutase (ecCuZnSOD) were examined in the white shrimp Litopenaeus vannamei (8.18 ± 0.86 g body weight) which had been denied food (starved) for up to 14–28 days. Among shrimp which had been starved for 7, 14, 21, and 28 days, 100%, 90%, 71%, and 59% survived, and they lost 3.2%, 7.3%, 9.2%, and 10.4% of their body weight, respectively. Hyaline cells (HCs), granular cells (GCs, including semi-granular cells), the total haemocyte count (THC), phenoloxidase (PO) activity, respiratory bursts (RBs), and SOD activity significantly decreased in shrimp which had been starved for 1, 1, 1, 5, 14, and 3 days, respectively. The expression of integrin ß significantly decreased after 0.5–5 days of starvation, whereas the expressions of LGBP, PX, proPO I, proPO II, ppA, and α2-M increased after 0.5–1 days. Transcripts of all genes except ecCuZnSOD decreased to the lowest level after 5 days, and tended to background values after 7 and 14 days. Cumulative mortality rates of 7-day-starved shrimp challenged with V. alginolyticus and WSSV were significantly higher than those of challenged control-shrimp for 1–7 and 1–4 days, respectively. In another experiment, immune parameters of shrimp which had been starved for 7 and 14 days and then received normal feeding (at 5% of their body weight daily) were examined after 3, 6, and 12 h, and 1, 3, and 5 days. All immune parameters of 7-day-starved shrimp were able to return to their baseline values after 5 days of re-feeding except for GCs, whereas all parameters of 14-day-starved shrimp failed to return to the baseline values even with 5 days of re-feeding. It was concluded that shrimp starved for 14 days exhibited three stages of modulation of gene expression, together with reductions in immune parameters, and decreased resistance against pathogens. PMID:24371579

Hydrogenolysis of Glycerol to Propylene Glycol on Nanosized Cu-Zn-Al Catalysts Prepared Using Microwave Process.

PubMed

Kim, Dong Won; Ha, Sang Ho; Moon, Myung Jun; Lim, Kwon Taek; Ryu, Young Bok; Lee, Sun Do; Lee, Man Sig; Hong, Seong-Soo

2015-01-01

Cu-Zn-Al catalysts were prepared using microwave-assisted process and co-precipitation methods. The prepared catalysts were characterized by XRD, BET, XPS and TPD of ammonia and their catalytic activity for the hydrogenolysis of glycerol to propylene glycol was also examined. The XRD patterns of Cu/Zn/Al mixed catalysts show CuO and ZnO crystalline phase regardless of preparation method. The highest glycerol hydrogenolysis conversion is obtained with the catalyst having a Cu/Zn/Al ratio of 2:2:1. Hydrogen pre-reduction of catalysts significantly enhanced both glycerol conversions and selectivity to propylene glycol. The glycerol conversion increased with an increase of reaction temperature. However, the selectivity to propylene glycol increased with an increase of temperature, and then declined to 30.5% at 523 K.

The Effect of (Ag, Ni, Zn)-Addition on the Thermoelectric Properties of Copper Aluminate

PubMed Central

Yanagiya, Shun-ichi; Van Nong, Ngo; Xu, Jianxiao; Pryds, Nini

2010-01-01

Polycrystalline bulk copper aluminate Cu1-x-yAgxByAlO2 with B = Ni or Zn were prepared by spark plasma sintering and subsequent thermal treatment. The influence of partial substitution of Ag, Ni and Zn for Cu-sites in CuAlO2 on the high temperature thermoelectric properties has been studied. The addition of Ag and Zn was found to enhance the formation of CuAlO2 phase and to increase the electrical conductivity. The addition of Ag or Ag and Ni on the other hand decreases the electrical conductivity. The highest power factor of 1.26 × 10-4 W/mK2 was obtained for the addition of Ag and Zn at 1,060 K, indicating a significant improvement compared with the non-doped CuAlO2 sample.

Effect of Copper Oxide Nanoparticles as a barrier for Efficiency Improvement in ZnO Dye-Sensitized Solar Cells

NASA Astrophysics Data System (ADS)

Sonthila, A.; Ruankham, P.; Choopun, S.; Wongratanaphisan, D.; Phadungdhitidhada, S.; Gardchareon, A.

2017-09-01

CuO nanoparticles (CuO NPs) were used as a barrier layer in ZnO dye-sensitized solar cells (DSSCs) to obtain high power conversion efficiency. The barrier layer was investigated in terms of the size of CuO NPs by varying power of pulsed Nd:YAG (1064 nm) laser ablation. Morphological and optical properties of CuO NPs were characterized by transmission electron microscopy (TEM), UV-visible spectrophotometry (UV-vis) and dynamic light scattering (DLS). It was found that the CuO NPs are rather spherical in shape with diameter in between 20 - 132 nm. In addition, the energy gap of CuO decreases with the increase of CuO NPs size. The power conversion efficiency of ZnO DSSCs was measured under illumination of simulated sunlight obtained from a solar simulator with the radiant power of 100 mW/cm2. The results showed that the ZnO DSSC with the CuO NPs with size of 37 nm exhibits the optimum power conversion efficiency of 1.01% which is higher than that of one without CuO NPs. Moreover, the power conversion efficiency of the ZnO DSSCs decreases with the increase of CuO NPs size.

Study of Cu2O\\ZnO nanowires heterojunction designed by combining electrodeposition and atomic layer deposition

NASA Astrophysics Data System (ADS)

Makhlouf, Houssin; Weber, Matthieu; Messaoudi, Olfa; Tingry, Sophie; Moret, Matthieu; Briot, Olivier; Chtoutou, Radhouane; Bechelany, Mikhael

2017-12-01

Cu2O/ZnO nanowires (NWs) heterojunctions were successfully prepared by combining Atomic layer Deposition (ALD) and Electrochemical Deposition (ECD) processes. The crystallinity, morphology and photoconductivity properties of the Cu2O/ZnO nanostructures have been investigated. The properties of the Cu2O absorber layer and the nanostructured heterojunction were studied in order to understand the mechanisms lying behind the low photoconductivity measured. It has been found that the interface state defects and the high resistivity of Cu2O film were limiting the photovoltaic properties of the prepared devices. The understanding presented in this work is expected to enable the optimization of solar cell devices based on Cu2O/ZnO nanomaterials and improve their overall performance.

Application of 67Cu Produced by 68Zn(n,n'p+d)67Cu to Biodistribution Study in Tumor-Bearing Mice

NASA Astrophysics Data System (ADS)

Sugo, Yumi; Hashimoto, Kazuyuki; Kawabata, Masako; Saeki, Hideya; Sato, Shunichi; Tsukada, Kazuaki; Nagai, Yasuki

2017-02-01

67Cu produced by the 68Zn(n,n'p+d)67Cu reaction was used for the first time to determine the biodistribution of 67CuCl2 in colorectal tumor-bearing mice. A high uptake of 67Cu was observed in the tumor as well as in the liver and kidney, which are the major organs for copper metabolism. The result showing 67Cu accumulation in the tumor suggests that 67CuCl2 can be a potential radionuclide agent for cancer radiotherapy. It should also encourage further studies on the therapeutic effect on small animals using an increased dose of 67Cu produced by the 68Zn(n,n'p+d)67Cu reaction using presently available intense neutrons.

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

Ritscher, A.; Helmholtz-Zentrum Berlin für Materialien und Energie, Hahn-Meitner-Platz 1, 14109 Berlin; Hoelzel, M.

In this work a series of stoichiometric Cu{sub 2}ZnSnS{sub 4} (CZTS) samples annealed at different temperatures in the range of 473–623 K were investigated. The temperature dependence of the Cu/Zn-order-disorder behavior was analyzed by neutron powder diffraction measurements. Cu fully occupies the 2a and Sn the 2b position within the whole temperature range. For Zn and the remaining Cu on sites 2d and 2c, a clear change from ordered to disordered kesterite structure is found. The critical temperature T{sub c} for this Landau-type second order transition was determined as 552±2 K. It was found that in Cu{sub 2}ZnSnS{sub 4} verymore » long annealing times are necessary to reach equilibrium at low temperatures. - Graphical abstract: The order-disorder transition in Cu{sub 2}ZnSnS{sub 4} was investigated using neutron diffraction techniques on samples annealed in the temperature range of 473–623 K. The critical temperature T{sub c} for this Landau-type second order transition was determined as 552±2 K. Display Omitted - Highlights: • The order-disorder transformation of Cu{sub 2}ZnSnS{sub 4} follows a Landau‐type behavior for a second order transition. • The critical exponent β is 0.57±0.06. • The critical temperature was determined as 552±2 K. • A fully ordered (within the standard deviation) Cu{sub 2}ZnSnS{sub 4} sample was synthesized.« less

Nanostructured hybrid ZnO thin films for energy conversion

PubMed Central

2011-01-01

We report on hybrid films based on ZnO/organic dye prepared by electrodeposition using tetrasulfonated copper phthalocyanines (TS-CuPc) and Eosin-Y (EoY). Both the morphology and porosity of hybrid ZnO films are highly dependent on the type of dyes used in the synthesis. High photosensitivity was observed for ZnO/EoY films, while a very weak photoresponse was obtained for ZnO/TS-CuPc films. Despite a higher absorption coefficient of TS-CuPc than EoY, in ZnO/EoY hybrid films, the excited photoelectrons between the EoY levels can be extracted through ZnO, and the porosity of ZnO/EoY can also be controlled. PMID:21711909

Impact of haloperidol and quetiapine on the expression of genes encoding antioxidant enzymes in human neuroblastoma SH-SY5Y cells.

PubMed

Schmidt, Andreas Johannes; Hemmeter, Ulrich Michael; Krieg, Jürgen-Christian; Vedder, Helmut; Heiser, Philip

2009-05-01

Antipsychotics are known to alter antioxidant activities in vivo. Therefore, the aim of the present study was to examine in the human neuroblastoma SH-SY5Y cell line the impact of a typical (haloperidol) and an atypical (quetiapine) antipsychotic on the expression of genes encoding the key enzymes of the antioxidant metabolism (Cu, Zn superoxide dismutase; Mn superoxide dismutase; glutathione peroxidase; catalase) and enzymes of the glutathione metabolism (gamma-glutamyl cysteine synthetase, glutathione-S-transferase, gamma-glutamyltranspeptidase, glutathione reductase). The cells were incubated for 24h with 0.3, 3, 30 and 300microM haloperidol and quetiapine, respectively; mRNA levels were measured by polymerase chain reaction. In the present study, we observed mostly significant decreases of mRNA contents. With respect to the key pathways, we detected mainly effects on the mRNA levels of the hydrogen peroxide detoxifying enzymes. Among the enzymes of the glutathione metabolism, glutathione-S-transferase- and gamma-glutamyltranspeptidase-mRNA levels showed the most prominent effects. Taken together, our results demonstrate a significantly reduced expression of genes encoding for antioxidant enzymes after treatment with the antipsychotics, haloperidol and quetiapine.

Copper/Zinc-Superoxide Dismutase Is Required for Oxytetracycline Resistance of Saccharomyces cerevisiae

PubMed Central

Avery, Simon V.; Malkapuram, Srividya; Mateus, Carolina; Babb, Kimberly S.

2000-01-01

Saccharomyces cerevisiae, along with other eukaryotes, is resistant to tetracyclines. We found that deletion of SOD1 (encoding Cu/Zn superoxide dismutase) rendered S. cerevisiae hypersensitive to oxytetracycline (OTC): a sod1Δ mutant exhibited a >95% reduction in colony-forming ability at an OTC concentration of 20 μg ml−1, whereas concentrations of up to 1,000 μg ml−1 had no effect on the growth of the wild type. OTC resistance was restored in the sod1Δ mutant by complementation with wild-type SOD1. The effect of OTC appeared to be cytotoxic and was not evident in a ctt1Δ (cytosolic catalase) mutant or in the presence of tetracycline. SOD1 transcription was not induced by OTC, suggesting that constitutive SOD1 expression is sufficient for wild-type OTC resistance. OTC uptake levels in wild-type and sod1Δ strains were similar. However, lipid peroxidation and protein oxidation were both enhanced during exposure of the sod1Δ mutant, but not the wild type, to OTC. We propose that Sod1p protects S. cerevisiae against a mode of OTC action that is dependent on oxidative damage. PMID:10613865

Digestibility and retention of zinc, copper, manganese, iron, calcium, and phosphorus in pigs fed diets containing inorganic or organic minerals.

PubMed

Liu, Y; Ma, Y L; Zhao, J M; Vazquez-Añón, M; Stein, H H

2014-08-01

The objective of this experiment was to measure the apparent total tract digestibility (ATTD) and the retention rate of Zn, Cu, Mn, and Fe in pigs fed either inorganic or organic sources of Zn, Cu, Mn, and Fe. The experimental design was a randomized complete block design with a 2 × 3 factorial arrangement of treatments. There were 2 types of diets (corn grits-based or corn-soybean meal [SBM]-based diets) and 3 micromineral treatments (basal micromineral premix [BMM], inorganic micromineral premix [IMM], and organic micromineral premix [OMM]). The BMM contained no added Zn, Cu, Mn, or Fe; the IMM microminerals were provided as sulfates of Zn, Cu, Mn, and Fe at 40, 50, 20, and 100 mg/kg, respectively. The OMM contained the same levels of the 4 microminerals as IMM, but Zn, Cu, Mn, and Fe in this premix were provided by Zn(2-hydroxy-4-methylthio butanoic acid [HMTBa])2, Cu(HMTBa)2, Mn(HMTBa)2, and FeGly, respectively. Forty-eight barrows (initial BW: 31.1 ± 4.2 kg) were housed individually and allowed ad libitum access to the corn grits diet with BMM for 2 wk. All pigs were then moved to metabolism cages and randomly assigned to 1 of the 6 treatment diets with 8 replicates per diet. Fecal and urine samples were collected for 5 d following a 5-d adaptation period. Compared with corn grits diets, pigs fed corn-SBM diets had greater (P < 0.05) absorption and retention of Zn, Cu, and Mn but less (P < 0.05) ATTD of Zn and Cu. Compared with BMM, supplementation of IMM or OMM increased (P < 0.05) absorption, retention, ATTD, and retention rate of Zn, Cu, Mn, and Fe. Compared with IMM, adding OMM to the corn-SBM diet improved (P < 0.05) the absorption and retention of Cu and Mn and the ATTD of Cu, but these differences were not observed in the corn grits diets (interaction, P < 0.05). In addition, adding OMM to the corn-SBM diet increased (P < 0.05) absorption and retention of Zn and Fe and ATTD of Zn, Mn, and Fe compared with adding IMM to the corn-SBM diet. Supplementation of OMM also increased (P < 0.05) the ATTD and retention rate of P in corn-SBM diets. Results indicate that Zn(HMTBa)2 has greater digestibility and Cu(HMTBa)2 and Mn(HMTBa)2 have greater digestibility and retention rates compared with their inorganic sulfates, if included in a corn-SBM diet. Supplementation of organic microminerals also improves the digestibility of P in a corn-SBM diet.

Site-selective XAFS spectroscopy tuned to surface active sites of Cu/ZnO and Cr/SiO2 catalysts.

PubMed

Izumi, Y; Nagamori, H; Kiyotaki, F; Minato, T

2001-03-01

XAFS (X-ray absorption fine structure) spectra were measured by using the fluorescence spectrometer for the emitted X-ray from sample. The chemical shifts between Cu0 and Cu1 and between CrIII and CrVI were evaluated. Tuning the fluorescence spectrometer to each energy, the Cu0 and CuI site-selective XANES for Cu/ZnO catalyst were measured. The first one was similar to the XANES of Cu metal and the second one was the 5 : 5 average of XANES for CuI sites + Cu metal. The population ratio of copper site of the Cu/ZnO catalyst was found to be Cu metal: Cu2O : CuI atomically dispersed on surface = 70(+/-23) : 22(+/-14) : 8(+/-5). Site-selective XANES for CrIII site of Cr/SiO2 catalyst was also studied.

Bioaccessibility and size distribution of metals in road dust and roadside soils along a peri-urban transect.

PubMed

Padoan, Elio; Romè, Chiara; Ajmone-Marsan, Franco

2017-12-01

Road dust (RD), together with surface soils, is recognized as one of the main sinks of pollutants in urban environments. Over the last years, many studies have focused on total and bioaccessible concentrations while few have assessed the bioaccessibility of size-fractionated elements in RD. Therefore, the distribution and bioaccessibility of Fe, Mn, Cd, Cr, Cu, Ni, Pb, Sb and Zn in size fractions of RD and roadside soils (<2.5μm, 2.5-10μm and 10-200μm) have been studied using aqua regia extraction and the Simple Bioaccessibility Extraction Test. Concentrations of metals in soils are higher than legislative limits for Cu, Cr, Ni, Pb and Zn. Fine fractions appear enriched in Fe, Mn, Cu, Pb, Sb and Zn, and 2.5-10μm particles are the most enriched. In RD, Cu, Pb, Sb and Zn derive primarily from non-exhaust sources, while Zn is found in greater concentrations in the <2.5μm fraction, where it most likely has an industrial origin. Elemental distribution across soils is dependent on land use, with Zn, Ni, Cu and Pb being present in higher concentrations at traffic sites. In addition, Fe, Ni and Cr feature greater bioaccessibility in the two finer fractions, while anthropic metals (Cu, Pb, Sb and Zn) do not. In RD, only Zn has significantly higher bioaccessibility at traffic sites compared to background, and the finest particles are always the most bioaccessible; >90% of Pb, Zn and Cu is bioaccessible in the <2.5μm fraction, while for Mn, Ni, Sb, Fe and Cr, values vary from 76% to 5%. In the 2.5-10μm fraction, the values were 89% for Pb, 67% for Zn and 60% for Cu. These results make the evaluation of the bioaccessibility of size-fractionated particles appear to be a necessity for correct estimation of risk in urban areas. Copyright © 2017 Elsevier B.V. All rights reserved.

Dye sensitized solar cells using catalytically active CuO-ZnO nanocomposite synthesized by single step method

NASA Astrophysics Data System (ADS)

Abraham, Nelsa; Rufus, Alex; Unni, C.; Philip, Daizy

2018-07-01

In the present paper we report a low cost, single step preparation method for the synthesis of CuO-ZnO nanocomposite through simple co-precipitation technique using oxalic acid. To have a better idea about the deviations brought about by the inclusion of CuO in ZnO lattice, pure ZnO nanoparticles synthesized from 0.1 M solutions were also investigated. X-ray diffraction studies showed that the composite contains only hexagonal wurtzite ZnO and monoclinic CuO structures. The magnetic studies of CuO-ZnO heterostructures were also conducted in order to elucidate the source of the ferromagnetism observed at room temperature. The catalytic efficiency of the as prepared nanocomposite was estimated by the degradation of methylene blue and eosin yellowish which also shows its suitability as a promising candidate in waste water treatment. The effect of chenodeoxycholic acid as a co-adsorbent in the performance of dye sensitized solar cells fabricated using the synthesized ZnO and the nanocomposite was also studied and significant improvement in photovoltaic performance has been obtained for nanocomposite based solar cell.

Non-blinking (Zn)CuInS/ZnS Quantum Dots Prepared by In Situ Interfacial Alloying Approach

PubMed Central

Zhang, Aidi; Dong, Chaoqing; Li, Liang; Yin, Jinjin; Liu, Heng; Huang, Xiangyi; Ren, Jicun

2015-01-01

Semiconductor quantum dots (QDs) are very important optical nanomaterials with a wide range of potential applications. However, blinking behavior of single QD is an intrinsic drawback for some biological and photoelectric applications based on single-particle emission. Herein we present a rational strategy for fabrication of non-blinking (Zn)CuInS/ZnS QDs in organic phase through in situ interfacial alloying approach. This new strategy includes three steps: synthesis of CuInS QDs, eliminating the interior traps of QDs by forming graded (Zn)CuInS alloyed QDs, modifying the surface traps of QDs by introducing ZnS shells onto (Zn)CuInS QDs using alkylthiols as sulfur source and surface ligands. The suppressed blinking mechanism was mainly attributed to modifying QDs traps from interior to exterior via a step-by-step modification. Non-blinking QDs show high quantum yield, symmetric emission spectra and excellent crystallinity, and will enable applications from biology to optoelectronics that were previously hindered by blinking behavior of traditional QDs. PMID:26458511

Electrochemiluminescence assay of Cu2+ by using one-step electrodeposition synthesized CdS/ZnS quantum dots.

PubMed

Zhao, Guanhui; Li, Xiaojian; Zhao, Yongbei; Li, Yueyuan; Cao, Wei; Wei, Qin

2017-08-21

A sensitive and selective method was proposed to detect Cu 2+ based on the electrochemiluminescence quenching of CdS/ZnS quantum dots (QDs). Herein, CdS/ZnS QDs were one-step electrodeposited directly on a gold electrode from an electrolyte (containing Cd(NO 3 ) 2 , Zn(NO 3 ) 2 , EDTA and Na 2 S 2 O 3 ) by cycling the potential from 0 to -1.8 V. The prepared CdS/ZnS QDs exhibited excellent solubility and strong and stable cathodic ECL activity. Meanwhile, Nafion was used to immobilize CdS/ZnS QDs. The quenching effect of Cu 2+ on the cathodic ECL of CdS/ZnS QDs was found to be selective and concentration dependent. The linear range for Cu 2+ detection was from 2.5 nM to 200 nM with a detection limit of 0.95 nM. Furthermore, the designed method for the detection of Cu 2+ can provide a reference for the detection of other heavy metal ions.

Structure and electronic properties of grain boundaries in earth-abundant photovoltaic absorber Cu2ZnSnSe4.

PubMed

Li, Junwen; Mitzi, David B; Shenoy, Vivek B

2011-11-22

We have studied the atomic and electronic structure of Cu(2)ZnSnSe(4) and CuInSe(2) grain boundaries using first-principles calculations. We find that the constituent atoms at the grain boundary in Cu(2)ZnSnSe(4) create localized defect states that promote the recombination of photon-excited electron and hole carriers. In distinct contrast, significantly lower density of defect states is found at the grain boundaries in CuInSe(2), which is consistent with the experimental observation that CuInSe(2) solar cells exhibit high conversion efficiency without the need for deliberate passivation. Our investigations suggest that it is essential to effectively remove these defect states in order to improve the conversion efficiency of solar cells with Cu(2)ZnSnSe(4) as photovoltaic absorber materials. © 2011 American Chemical Society

Intrinsically Radioactive [64Cu]CuInS/ZnS Quantum Dots for PET and Optical Imaging: Improved Radiochemical Stability and Controllable Cerenkov Luminescence

PubMed Central

2015-01-01

Functionalized quantum dots (QDs) have been widely explored for multimodality bioimaging and proven to be versatile agents. Attaching positron-emitting radioisotopes onto QDs not only endows their positron emission tomography (PET) functionality, but also results in self-illuminating QDs, with no need for an external light source, by Cerenkov resonance energy transfer (CRET). Traditional chelation methods have been used to incorporate the radionuclide, but these methods are compromised by the potential for loss of radionuclide due to cleavage of the linker between particle and chelator, decomplexation of the metal, and possible altered pharmacokinetics of nanomaterials. Herein, we described a straightforward synthesis of intrinsically radioactive [64Cu]CuInS/ZnS QDs by directly incorporating 64Cu into CuInS/ZnS nanostructure with 64CuCl2 as synthesis precursor. The [64Cu]CuInS/ZnS QDs demonstrated excellent radiochemical stability with less than 3% free 64Cu detected even after exposure to serum containing EDTA (5 mM) for 24 h. PEGylation can be achieved in situ during synthesis, and the PEGylated radioactive QDs showed high tumor uptake (10.8% ID/g) in a U87MG mouse xenograft model. CRET efficiency was studied as a function of concentration and 64Cu radioactivity concentration. These [64Cu]CuInS/ZnS QDs were successfully applied as an efficient PET/self-illuminating luminescence in vivo imaging agents. PMID:25549258

Intrinsically radioactive [64Cu]CuInS/ZnS quantum dots for PET and optical imaging: improved radiochemical stability and controllable Cerenkov luminescence.

PubMed

Guo, Weisheng; Sun, Xiaolian; Jacobson, Orit; Yan, Xuefeng; Min, Kyunghyun; Srivatsan, Avinash; Niu, Gang; Kiesewetter, Dale O; Chang, Jin; Chen, Xiaoyuan

2015-01-27

Functionalized quantum dots (QDs) have been widely explored for multimodality bioimaging and proven to be versatile agents. Attaching positron-emitting radioisotopes onto QDs not only endows their positron emission tomography (PET) functionality, but also results in self-illuminating QDs, with no need for an external light source, by Cerenkov resonance energy transfer (CRET). Traditional chelation methods have been used to incorporate the radionuclide, but these methods are compromised by the potential for loss of radionuclide due to cleavage of the linker between particle and chelator, decomplexation of the metal, and possible altered pharmacokinetics of nanomaterials. Herein, we described a straightforward synthesis of intrinsically radioactive [(64)Cu]CuInS/ZnS QDs by directly incorporating (64)Cu into CuInS/ZnS nanostructure with (64)CuCl2 as synthesis precursor. The [(64)Cu]CuInS/ZnS QDs demonstrated excellent radiochemical stability with less than 3% free (64)Cu detected even after exposure to serum containing EDTA (5 mM) for 24 h. PEGylation can be achieved in situ during synthesis, and the PEGylated radioactive QDs showed high tumor uptake (10.8% ID/g) in a U87MG mouse xenograft model. CRET efficiency was studied as a function of concentration and (64)Cu radioactivity concentration. These [(64)Cu]CuInS/ZnS QDs were successfully applied as an efficient PET/self-illuminating luminescence in vivo imaging agents.

Point defects in Cu 2ZnSnSe 4(CZTSe): Resonant X-ray diffraction study of the low-temperature order/disorder transition

DOE PAGES

Schelhas, L. T.; Stone, K. H.; Harvey, S. P.; ...

2017-07-25

We report that the interest in Cu 2ZnSn(S,Se) 4 (CZTS) for photovoltaic applications is motivated by similarities to Cu(In,Ga)Se 2 while being comprised of non-toxic and earth abundant elements. However, CZTS suffers from a V oc deficit, where the V oc is much lower than expected based on the band gap, which may be the result of a high concentration of point-defects in the CZTS lattice. Recently, reports have observed a low-temperature order/disorder transition by Raman and optical spectroscopies in CZTS films and is reported to describe the ordering of Cu and Zn atoms in the CZTS crystal structure. Tomore » directly determine the level of Cu/Zn ordering, we have used resonant-XRD, a site, and element specific probe of long range order. We used CZTSe films annealed just below and quenched from just above the transition temperature; based on previous work, the Cu and Zn should be ordered and highly disordered, respectively. Our data show that there is some Cu/Zn ordering near the low temperature transition but significantly less than high chemical order expected from Raman. Finally, to understand both our resonant-XRD results and the Raman results, we present a structural model that involves antiphase domain boundaries and accommodates the excess Zn within the CZTS lattice.« less

Phytoextraction of risk elements by willow and poplar trees.

PubMed

Kacálková, Lada; Tlustoš, Pavel; Száková, Jiřina

2015-01-01

To characterize the phytoextraction efficiency of two clones of willow trees (Salix x smithiana Willd., Salix rubens) and two clones of poplar trees (Populus nigra x maximowiczii, Populus nigra Wolterson) were planted in contaminated soil (0.4-2.0 mg Cd.kg(-1), 78-313 mg Zn.kg(-1), 21.3-118 mg Cu.kg(-1)). Field experiment was carried out in Czech Republic. The study investigated their ability to accumulate heavy metals (Cd, Zn, and Cu) in harvestable plant parts. The poplars produced higher amount of biomass than willows. Both Salix clones accumulated higher amount of Cd, Zn and Cu in their biomass (maximum 6.8 mg Cd.kg(-1), 909 mg Zn.kg(-1), and 17.7 mg Cu.kg(-1)) compared to Populus clones (maximum 2.06 mg Cd.kg(-1), 463 mg Zn.kg(-1), and 11.8 mg Cu.kg(-1)). There were no significant differences between clones of individual species. BCs for Cd and Zn were greater than 1 (the highest in willow leaves). BCs values of Cu were very low. These results indicate that Salix is more suitable plant for phytoextraction of Cd and Zn than Populus. The Cu phytoextraction potential of Salix and Populus trees was not confirmed in this experiment due to low soil availability of this element.

Effects of Cr/Zn Substitutions on Dielectric Properties of CaCu{sub 3}Ti{sub 4}O{sub 12}(CCTO) Ceramics

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

Rajmi, R.; Yahya, A. K.; Deni, M. S. M.

2010-07-07

Effects of Zn and Cr substitutions on dielectric properties of CaCu{sub 3-x}Zn{sub x}Ti{sub 4-y}Cr{sub y}O{sub 12} ceramics are reported. Dielectric measurements at room temperature for un-substituted CaCu{sub 3-x}Zn{sub x}Ti{sub 4-y}Cr{sub y}O{sub 12}(x = 0, y = 0) between 10{sup 2}-10{sup 6} Hz showed dielectric constant of 2.7x10{sup 4} at 10{sup 2} Hz. Substitution of Zn for Cu in CaCu{sub 3-x}Zn{sub xTi{sub 4{sub -{sub yCr{sub yO{sub 1{sub 2}}}}}}}(y = 0, x = 0.10, 0.50)caused dielectric constant to drop with increasing x. Cr substitution at Ti-site in CaCu{sub 3-x}Zn{sub xTi{sub 4{sub -{sub yCr{sub yO{sub 1{sub 2}}}}}}}(x = 0, x = 0,) alsomore » caused decrease in dielectric constant. However, at x = 0.50, the dielectric constant at low frequency was enhanced compared to the un-substituted sample. Our results indicate that Cu and Ti sites play an important role in the formation of Internal Barrier Layer Capacitance (IBLC) in CCTO.« less

Flavonoids with DNA strand-scission activity from Rhus javanica var. roxburghiana.

PubMed

Lin, Chun-Nan; Chen, Hui-Ling; Yen, Ming-Hong

2008-01-01

The flavonoids isolated from the stems of Rhus javanica var. roxburghiana, taxifolin (1), fisetin (2), fustin (3), 3,7,4'-trihydroxyflavanone (4) and 3,7,4'-trihydroxyflavone (5) caused breakage of supercoiled plasmid pBR322 DNA in the presence of Cu(II). Cu(I) was shown to be an essential intermediate by using the Cu(I)-specific sequestering reagent neocuproine. The Cu(II)-mediated DNA scissions induced by 1, 2, 3 and 5 were inhibited by the addition of catalase and exhibited DNA strand break by the addition of KI and superoxide dimutase (SOD), while in the Cu(II)-mediated DNA scissions induced by 4 was inhibited by the addition of KI, SOD, and catalase. It is concluded that 1, 2, 3, and 5 can induce H2O2 and superoxide anion, while 4 can induce OH* and H2O2 and subsequent oxidative damage of DNA in the presence of Cu(II).

Ab initio investigation on hydrogen adsorption capability in Zn and Cu-based metal organic frameworks

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

Tanuwijaya, V. V., E-mail: viny.veronika@gmail.com; Hidayat, N. N., E-mail: avantgarde.vee@gmail.com; Agusta, M. K., E-mail: kemal@fti.itb.ac.id

2015-09-30

One of the biggest challenge in material technology for hydrogen storage application is to increase hydrogen uptake in room temperature and pressure. As a class of highly porous material, Metal-Organic Frameworks (MOF) holds great potential with its tunable structure. However, little is known about the effect of metal cluster to its hydrogen storage capability. Investigation on this matter has been carried out carefully on small cluster of Zn and Cu-based MOF using first principles method. The calculation of two distinct building units of MOFs, namely octahedral and paddle-wheel models, have been done with B3LYP density functional method using 6-31G(d,p) andmore » LANL2DZ basis sets. From geometry optimization of Zn-based MOF linked by benzene-dicarboxylate (MOF-5), it is found that hydrogen tends to keep distance from metal cluster group and stays above benzene ring. In the other hand, hydrogen molecule prefers to stay atop of the exposed Cu atom in Cu-based MOF system linked by the same linker group (Cu-bdc). Calculated hydrogen binding enthalpies for Zn and Cu octahedral cages at ZnO{sub 3} sites are 1.64kJ/mol and 2.73kJ/mol respectively, while hydrogen binding enthalpies for Zn and Cu paddle-wheel cages calculated on top of metal atoms are found to be at 6.05kJ/mol and 6.10kJ/mol respectively. Major difference between Zn-MOF-5 and Cu-bdc hydrogen uptake performance might be caused by unsaturated metal sites present in Cu-bdc system and the influence of their geometric structures, although a small difference on binding energy in the type of transition metal used is also observed. The comparison between Zn and Cu-based MOF may contribute to a comprehensive understanding of metal clusters and the importance of selecting best transition metal for design and synthesis of metal-organic frameworks.« less

Structure and mechanism of Cu- and Ni-substituted analogs of metallo-β-lactamase L1

PubMed Central

Hu, Zhenxin; Spadafora, Lauren J.; Hajdin, Christine E.; Bennett, Brian; Crowder, Michael W.

2009-01-01

In an effort to further probe metal binding to metallo-β-lactamase L1 (mβl L1), Cu- (Cu-L1) and Ni-substituted (Ni-L1) L1 were prepared and characterized by kinetic and spectroscopic studies. Cu-L1 bound 1.7 equivalents of Cu and small amounts of Zn(II) and Fe. The EPR spectrum of Cu-L1 exhibited two overlapping, axial signals, indicative of type 2 sites with distinct affinities for Cu(II). Both signals indicated multiple nitrogen ligands. Despite the expected proximity of the Cu(II) ions, however, only indirect evidence was found for spin-spin coupling. Cu-L1 exhibited higher kcat (96 s−1) and Km (224 μM) values, as compared to the values of dinuclear Zn(II)-containing L1, when nitrocefin was used as substrate. The Ni-L1 bound 1 equivalent of Ni and 0.3 equivalents of Zn(II). Ni-L1 was EPR-silent, suggesting that the oxidation state of nickel was +2; this suggestion was confirmed by 1H NMR spectra, which showed relatively sharp proton resonances. Stopped-flow kinetic studies showed that ZnNi-L1 stabilized significant amounts of the nitrocefin-derived intermediate and that the decay of intermediate is rate-limiting. 1H NMR spectra demonstrate that Ni(II) binds in the Zn2 site and that the ring-opened product coordinates Ni(II). Both Cu-L1 and ZnNi-L1 hydrolyze cephalosporins and carbapenems, but not penicillins, suggesting that the Zn2 site modulates substrate preference in mβ1 L1. These studies demonstrate that the Zn2 site in L1 is very flexible and can accommodate a number of different transition metal ions; this flexibility could possibly offer an organism that produces L1 an evolutionary advantage when challenged with β-lactam containing antibiotics. PMID:19228020

Synthesis, structural, optical and dielectric properties of transition metal doped ZnMnO nanoparticles by sol-gel combustion technique

NASA Astrophysics Data System (ADS)

Dar, M. A.; Varshney, Dinesh

2018-02-01

Nanocrystalline samples of Zn0.94Mn0.06O and transition metal (TM) doped Zn0.94Mn0.01TM0.05O (TM = Co, Ni, and Cu) were prepared by sol-gel auto combustion method. X-ray diffraction (XRD) pattern infers that all synthesized samples except Zn0.94Mn0.01Ni0.05O and Zn0.94Mn0.01Cu0.05O with secondary phases of NiO and CuO are in single phase with hexagonal wurtzite structure (P63mc space group). Raman spectroscopy reveals four vibrational phonon modes are centered at 331, 380, 410, and 438 cm-1, assigned as E2 (H)-E2(L), A1(TO), E1(TO), and E1(LO) modes, respectively. A Raman spectrum of Zn0.94Mn0.01TM0.05O is entirely different from undoped Zn0.94Mn0.06O sample. Also, the infrared spectrum of transition metal doped samples is completely different from undoped Zn0.94Mn0.06O. Similar spectra are observed for Zn0.94Mn0.01Co0.05O, Zn0.94Mn0.01NiO, Zn0.94Mn0.01Cu0.05O and Zn0.94Mn0.01Zn0.05O samples. It was found that the band gap of Zn0.94Mn0.06O increased from 3.19 to 3.25eV by doping 5% transition metal oxide. Improved dielectric constant and reduced dielectric loss is measured for Zn0.94Mn0.01Ni/Cu0.05O as compared to Zn0.94Mn0.06O.

Elemental Precursor Solution Processed (Cu1-xAgx)2ZnSn(S,Se)4 Photovoltaic Devices with over 10% Efficiency.

PubMed

Qi, Yafang; Tian, Qingwen; Meng, Yuena; Kou, Dongxing; Zhou, Zhengji; Zhou, Wenhui; Wu, Sixin

2017-06-28

The partial substitution of Cu + with Ag + into the host lattice of Cu 2 ZnSn(S,Se) 4 thin films can reduce the open-circuit voltage deficit (V oc,deficit ) of Cu 2 ZnSn(S,Se) 4 (CZTSSe) solar cells. In this paper, elemental Cu, Ag, Zn, Sn, S, and Se powders were dissolved in solvent mixture of 1,2-ethanedithiol (edtH 2 ) and 1,2-ethylenediamine (en) and used for the formation of (Cu 1-x Ag x ) 2 ZnSn(S,Se) 4 (CAZTSSe) thin films with different Ag/(Ag + Cu) ratios. The key feature of this approach is that the impurity atoms can be absolutely excluded. Further results indicate that the variations of grain size, band gap, and depletion width of the CAZTSSe layer are generally determined by Ag substitution content. Benefiting from the V oc enhancement (∼50 mV), the power conversion efficiency is successfully increased from 7.39% (x = 0) to 10.36% (x = 3%), which is the highest efficiency of Ag substituted devices so far.

Electronic state and superconductivity of YBa2Cu3-xO7-y (M=Al,Zn and Sn) systems

NASA Technical Reports Server (NTRS)

Zhao, Y.; Zhang, Q. R.; Zhang, H.

1990-01-01

A series of YBa2Cu(3-x)MxO(7-y) (M=Al,Zn and Sn) single phase samples were prepared, and the measurements of the crystal structure, oxygen content, electric resistivity, thermoelectric power, Mossbauer spectrum, XPS and superconductivity were performed. The experimental results of X ray powder diffraction, Mossbauer spectrum and oxygen content show that the Zn(2+) and the Al(3+) occupy the Cu(2) site in Cu-O planes and the Cu(1) site in Cu-O chains respectively, but the Sn(4+) occupies both the Cu(1) sites. As regards the properties in superconducting state, both the Zn(2+) and the Al(3+) depress T(sub c) strongly, but the Sn(4+) does not. As for the electronic transport properties in normal state, the system doped by Al(3+) displays a rapid increase of resistivity and some electron localization-like effects, and the thermoelectric power enhances obviously; the series contained Zn(2+) almost shows no changes of electric resistivity but the sign of the thermoelectric power is reversed. Other results are given and briefly discussed.

High-speed electrodeposition of copper-tin-zinc stacks from liquid metal salts for Cu2ZnSnSe4 solar cells.

PubMed

Steichen, Marc; Malaquias, João C; Arasimowicz, Monika; Djemour, Rabie; Brooks, Neil R; Van Meervelt, Luc; Fransaer, Jan; Binnemans, Koen; Dale, Phillip J

2017-01-16

Cu 2 ZnSnSe 4 -based solar cells with 5.5% power conversion efficiency were fabricated from Cu/Sn/Zn stacks electrodeposited from liquid metal salts. These electrolytes allow metal deposition rates one order of magnitude higher than those of other deposition methods.

Influence of stacking fault energy on defect structures and microhardness of Cu and Cu alloys.

PubMed

Tao, Jing-Mei; Li, Dai; Li, Cai-Ju; Zhu, Xin-Kun

2011-12-01

Nano-structured Cu, Cu-10 wt%Zn and Cu-2 wt%Al with stacking fault energies (SFE) of 78, 35 and 37 mJ/m2, respectively, were preprared through high energy ball milling. X-ray diffraction and Vickers microharness test were used to investigate the microstructure and microhardness of all the samples after ball milling. X-ray diffraction measurements indicate that lower SFEs lead both to decrease in grain size and increase in microstrain, dislocation and twin densities for Cu-10 wt%Zn and Cu-2 wt%Al after 5 h of ball milling. The microhardnesses of Cu-10 wt%Zn and Cu-2 wt%Al reach to nearly the same values of 2.5 GPa after 5 h of ball milling, which is higher than that of Cu of 2.0 GPa. Two factors are considered to contribute to the finer grian size and higher microhardness of Cu-10 wt%Zn and Cu-2 wt%Al: (1) the effect of solid solution strengthening, which result in the interaction of solute atoms with screw dislocations; (2) the introduction of deformation twins during ball milling process by the decreasing of SFE, which results in the grain refinement.

Transcription regulation of gene expression in rat brown adipose tissue in response to unloading or 2G loading during growing period

NASA Astrophysics Data System (ADS)

Watanabe, S.; Hitomi, Y.; Kawano, F.; Ohira, Y.; Kizaki, T.; Nakano, N.; Sakurai, T.; Izawa, T.; Suzuki, K.; Sudoh, M.; Roy, R. R.; Ohno, H.

2007-05-01

The effects were investigated of long-term unloading and macrogravity on the expression of 15 genes at the mRNA levels in brown adipose tissue (BAT) from rat pups, particularly focusing on uncoupling protein (UCP) family, nitric oxide synthase (NOS) isoenzymes, and antioxidant enzymes. The animals in the unloaded group (a simulation model of spaceflight) were hindlimb-unloaded by tail suspension between postnatal day 4 and month 3, followed by 2-mo ambulation recovery. Moreover, centrifugation at 2G (an imitation of the hypergravity effects) was performed during the same period as the unloading, also followed by 2-mo ambulation recovery (adaptation to 1G from 2G). Compared with the age-matched control group, significantly lower expression levels of mRNA for UCP2, iNOS, and Cu,Zn-superoxide dismutase (Cu, Zn-SOD) in BAT were observed immediately after unloading, but not immediately after exposure to 2G. During 2-mo ambulation recovery from both extreme conditions, the expression of mRNA for Mn-SOD was enhanced, suggesting an increase in oxidative stress. These findings suggest that both micro- and macrogravity may have some influence upon the function of BAT, and that changes in the BAT function may be involved in the mechanisms subserving adaptation to such extreme conditions by what humans have to be faced with during the spaceflight and return to 1G.

Optical and thermogravimetric analysis of Zn1-xCuxS/PVA nanocomposite films

NASA Astrophysics Data System (ADS)

Mohamed, Mohamed Bakr; Heiba, Zein K.; Imam, N. G.

2018-07-01

Cu doped ZnS nanoparticles with cubic blend structure had been prepared successfully through thermolysis route and then composited with poly vinyl alcohol using casting method. Zn1-xCuxS/PVA nanocomposites were characterized using different characterization techniques. The quantum dot nature of the ZnS:Cu phase was confirmed by transmission electron microscope technique. Thermal stability was studied by thermogravimetric analysis. The ultra violet measurements illustrated that addition of Zn1-xCuxS nanoparticles to PVA matrix increased the film absorbance. Furthermore, the energy gap and refractive index of the composites were obtained from ultra violet and photoluminescence spectrophotometers. The photoluminescence spectra of ZnS:Cu/PVA nanocomposite films demonstrated a quite broad emission peak at 435 nm with highest photoluminescence intensity in nanocomposite doped with 1% Cu.

Antioxidant Expression Response to Free Radicals in Active Men and Women Fallowing to a Session Incremental Exercise; Numerical Relationship Between Antioxidants and Free Radicals.

PubMed

Baghaiee, Behrouz; Aliparasti, Mohammad Reza; Almasi, Shohreh; Siahkuhian, Marefat; Baradaran, Behzad

2016-06-01

Energy production is a necessary process to continue physical activities, and exercise is associated with more oxygen consumption and increase of oxidative stress. what seems important is the numerical relationship between antioxidant and free radicals. Although the activity of some enzymes increases with physical activities, but it is possible that gene expression of this enzyme is not changed during exercise. The aim of the present study is to investigate the antioxidant enzymes gene expression and changes in malondialdehyde (MDA) and total antioxidant capacity (TAC) levels in men and women affected by a session of incremental exercise and to carefully and numerically assess the relationship between MDA changes and gene expression and activity of antioxidant enzymes. 12 active men and 12 active women (21 - 24 years old) participated voluntarily in this study. Peripheral blood samples were taken from the subjects in three phases, before and after graduated exercise test (GXT) and 3 hours later (recovery). The gene expression of manganese superoxide dismutase (MnSOD) enzyme increased significantly in women in the recovery phase (P < 0.05). Catalase gene expression significantly increased in men in both phases (immediately & recovery) (P < 0.05). But the changes in active women were only significant immediately after the exercise. TAC levels increased significantly in men in the recovery phase and in active women immediately after the exercise (P < 0.05). MDA activity also increased significantly in men in both phases (P < 0.05). However, in women the increase was significant only in the recovery phase (P < 0.05). There was a reverse relationship between changes in MnSOD and copper- and zinc-containing superoxide dismutase (Cu/ZnSOD) levels and MDA in men (P < 0.05). In active women there was also a significant relationship between changes in MDA and gene expression of Cu/ZnSOD and TAC (P < 0.05). The increase in free radicals during incremental exercises challenges gene expression and activity of antioxidant enzymes. However, despite the negative effects of free radicals, in women, activity and gene expression of antioxidant enzymes respond appropriately to free radicals.

Di (2-ethylhexyl) phthalate inhibits growth of mouse ovarian antral follicles through an oxidative stress pathway

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

Wang, Wei, E-mail: weiwang2@illinois.edu; Craig, Zelieann R., E-mail: zelieann@illinois.edu; Basavarajappa, Mallikarjuna S., E-mail: mbasava2@illinois.edu

2012-01-15

Di (2-ethylhexyl) phthalate (DEHP) is a plasticizer that has been shown to inhibit growth of mouse antral follicles, however, little is known about the mechanisms by which DEHP does so. Oxidative stress has been linked to follicle growth inhibition as well as phthalate-induced toxicity in non-ovarian tissues. Thus, we hypothesized that DEHP causes oxidative stress and that this leads to inhibition of the growth of antral follicles. To test this hypothesis, antral follicles isolated from CD-1 mice (age 31–35 days) were cultured with vehicle control (dimethylsulfoxide [DMSO]) or DEHP (1–100 μg/ml) ± N-acetyl cysteine (NAC, an antioxidant at 0.25–1 mM).more » During culture, follicles were measured daily. At the end of culture, follicles were collected and processed for in vitro reactive oxygen species (ROS) assays to measure the presence of free radicals or for measurement of the expression and activity of various key antioxidant enzymes: Cu/Zn superoxide dismutase (SOD1), glutathione peroxidase (GPX) and catalase (CAT). The results indicate that DEHP inhibits the growth of follicles compared to DMSO control and that NAC (0.25–1 mM) blocks the ability of DEHP to inhibit follicle growth. Furthermore, DEHP (10 μg/ml) significantly increases ROS levels and reduces the expression and activity of SOD1 compared to DMSO controls, whereas NAC (0.5 mM) rescues the effects of DEHP on ROS levels and SOD1. However, the expression and activity of GPX and CAT were not affected by DEHP treatment. Collectively, these data suggest that DEHP inhibits follicle growth by inducing production of ROS and by decreasing the expression and activity of SOD1. -- Highlights: ► DEHP inhibits growth and increases reactive oxygen species in ovarian antral follicles in vitro. ► NAC rescues the effects of DEHP on the growth and reactive oxygen species levels in follicles. ► DEHP decreases the expression and activity of Cu/Zn superoxide dismutase, which can be rescued by NAC, in antral follicles.« less

Cu/Zn superoxide dismutase and the proton ATPase Pma1p of Saccharomyces cerevisiae

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

Baron, J. Allen; Chen, Janice S.; Culotta, Valeria C., E-mail: vculott1@jhu.edu

2015-07-03

In eukaryotes, the Cu/Zn containing superoxide dismutase (SOD1) plays a critical role in oxidative stress protection as well as in signaling. We recently demonstrated a function for Saccharomyces cerevisiae Sod1p in signaling through CK1γ casein kinases and identified the essential proton ATPase Pma1p as one likely target. The connection between Sod1p and Pma1p was explored further by testing the impact of sod1Δ mutations on cells expressing mutant alleles of Pma1p that alter activity and/or post-translational regulation of this ATPase. We report here that sod1Δ mutations are lethal when combined with the T912D allele of Pma1p in the C-terminal regulatory domain.more » This “synthetic lethality” was reversed by intragenic suppressor mutations in Pma1p, including an A906G substitution that lies within the C-terminal regulatory domain and hyper-activates Pma1p. Surprisingly the effect of sod1Δ mutations on Pma1-T912D is not mediated through the Sod1p signaling pathway involving the CK1γ casein kinases. Rather, Sod1p sustains life of cells expressing Pma1-T912D through oxidative stress protection. The synthetic lethality of sod1Δ Pma1-T912D cells is suppressed by growing cells under low oxygen conditions or by treatments with manganese-based antioxidants. We now propose a model in which Sod1p maximizes Pma1p activity in two ways: one involving signaling through CK1γ casein kinases and an independent role for Sod1p in oxidative stress protection. - Highlights: • In yeast, the anti-oxidant enzyme SOD1 promotes activity of the proton ATPase Pma1p. • Cells expressing a T912D variant of Pma1p are not viable without SOD1. • SOD1 is needed to protect Pma1-T912D expressing cells from severe oxidative damage. • SOD1 activates Pma1p through casein kinase signaling and oxidative stress protection.« less

Effects of environmental stress on mRNA expression levels of seven genes related to oxidative stress and growth in Atlantic salmon Salmo salar L. of farmed, hybrid and wild origin.

PubMed

Solberg, Monica F; Kvamme, Bjørn Olav; Nilsen, Frank; Glover, Kevin A

2012-12-05

Ten generations of domestication selection has caused farmed Atlantic salmon Salmo salar L. to deviate from wild salmon in a range of traits. Each year hundreds of thousands of farmed salmon escape into the wild. Thus, interbreeding between farmed escapees and wild conspecifics represents a significant threat to the genetic integrity of wild salmon populations. In a previous study we demonstrated how domestication has inadvertently selected for reduced responsiveness to stress in farmed salmon. To complement that study, we have evaluated the expression of seven stress-related genes in head kidney of salmon of farmed, hybrid and wild origin exposed to environmentally induced stress. In general, the crowding stressor used to induce environmental stress did not have a strong impact on mRNA expression levels of the seven genes, except for insulin-like growth factor-1 (IGF-1) that was downregulated in the stress treatment relative to the control treatment. mRNA expression levels of glutathione reductase (GR), Cu/Zn superoxide dismutase (Cu/Zn SOD), Mn superoxide dismutase (Mn SOD), glutathione peroxidase (GP) and IGF-1 were affected by genetic origin, thus expressed significantly different between the salmon of farmed, hybrid or wild origin. A positive relationship was detected between body size of wild salmon and mRNA expression level of the IGF-1 gene, in both environments. No such relationship was observed for the hybrid or farmed salmon. Farmed salmon in this study displayed significantly elevated mRNA levels of the IGF-1 gene relative to the wild salmon, in both treatments, while hybrids displayed a non additive pattern of inheritance. As IGF-1 mRNA levels are positively correlated to growth rate, the observed positive relationship between body size and IGF-1 mRNA levels detected in the wild but neither in the farmed nor the hybrid salmon, could indicate that growth selection has increased IGF-1 levels in farmed salmon to the extent that they may not be limiting growth rate.

Effects of environmental stress on mRNA expression levels of seven genes related to oxidative stress and growth in Atlantic salmon Salmo salar L. of farmed, hybrid and wild origin

PubMed Central

2012-01-01

Background Ten generations of domestication selection has caused farmed Atlantic salmon Salmo salar L. to deviate from wild salmon in a range of traits. Each year hundreds of thousands of farmed salmon escape into the wild. Thus, interbreeding between farmed escapees and wild conspecifics represents a significant threat to the genetic integrity of wild salmon populations. In a previous study we demonstrated how domestication has inadvertently selected for reduced responsiveness to stress in farmed salmon. To complement that study, we have evaluated the expression of seven stress-related genes in head kidney of salmon of farmed, hybrid and wild origin exposed to environmentally induced stress. Results In general, the crowding stressor used to induce environmental stress did not have a strong impact on mRNA expression levels of the seven genes, except for insulin-like growth factor-1 (IGF-1) that was downregulated in the stress treatment relative to the control treatment. mRNA expression levels of glutathione reductase (GR), Cu/Zn superoxide dismutase (Cu/Zn SOD), Mn superoxide dismutase (Mn SOD), glutathione peroxidase (GP) and IGF-1 were affected by genetic origin, thus expressed significantly different between the salmon of farmed, hybrid or wild origin. A positive relationship was detected between body size of wild salmon and mRNA expression level of the IGF-1 gene, in both environments. No such relationship was observed for the hybrid or farmed salmon. Conclusion Farmed salmon in this study displayed significantly elevated mRNA levels of the IGF-1 gene relative to the wild salmon, in both treatments, while hybrids displayed a non additive pattern of inheritance. As IGF-1 mRNA levels are positively correlated to growth rate, the observed positive relationship between body size and IGF-1 mRNA levels detected in the wild but neither in the farmed nor the hybrid salmon, could indicate that growth selection has increased IGF-1 levels in farmed salmon to the extent that they may not be limiting growth rate. PMID:23217180

Photocatalytic property and structural stability of CuAl-based layered double hydroxides

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

Lv, Ming; Liu, Haiqiang, E-mail: Liuhaiqiang1980@126.com

2015-07-15

Three types of CuMAl layered double hydroxides (LDHs, M=Mg, Zn, Ni) were successfully synthesized by coprecipitation. Powder X-ray diffraction (XRD), inductively coupled plasma atomic emission spectrometry (ICP-AES) and UV–Vis diffuse reflectance spectrum (UV–vis) were used to confirm the formation of as-synthesized solids with good crystal structure. The photocatalytic activity of those LDH materials for CO{sub 2} reduction under visible light was investigated. The experimental results show that CuNiAl-LDHs with narrowest band gap and largest surface areas behave highest efficiency for methanol generation under visible light compared with CuMgAl-LDHs and CuZnAl-LDHs. The CuNiAL-LDH showed high yield for methanol production i.e. 0.210more » mmol/g h, which was high efficient. In addition, the influence of the different M{sup 2+} on the structures and stability of the CuMAl-LDHs was also investigated by analyzing the geometric parameters, electronic arrangement, charge populations, hydrogen-bonding, and binding energies by density functional theory (DFT) analysis. The theoretical calculation results show that the chemical stability of LDH materials followed the order of CuMgAl-LDHs>CuZnAl-LDHs>CuNiAl-LDHs, which is just opposite with the photocatalytic activity and band gaps of three materials. - Graphical abstract: The host–guest calculation models and XRD patterns of CuMAl-LDHs: CuMgAl-LDHs (a), CuZnAl-LDHs (b) and CuNiAl-LDHs (c). - Highlights: • Three types of CuMAl layered double hydroxides (LDHs, M=Mg, Zn, Ni) has been synthesized. • CuMgNi shows narrower band gap and more excellent textural properties than other LDHs. • The band gap: CuMgAl« less

Altered serum copper homeostasis suggests higher oxidative stress and lower antioxidant capability in patients with chronic hepatitis B.

PubMed

Huang, Yansong; Zhang, Yuan; Lin, Zhexuan; Han, Ming; Cheng, Hongqiu

2018-06-01

Copper homeostasis can be altered by inflammation. This study aimed to investigate the alteration of serum copper homeostasis and to explore its clinical significance in patients with chronic hepatitis B (CHB).Thirty-two patients with CHB and 10 aged- and sex-matched healthy controls were recruited. Analyses included serum levels of total copper (TCu), copper ions (Cu), small molecule copper (SMC), ceruloplasmin (CP), Cu/Zn superoxide dismutase 1 (SOD1), urinary copper, and the activities of serum CP and SOD1.The serum TCu and urinary copper levels in patients with CHB were significantly higher than the controls (P = .04 and .003), while the serum Cu was lower than the controls (P = .0002). CP and SOD1 activities in the serum were significantly lower in patients with CHB compared to controls (P = .005) despite higher serum concentrations. In addition, serum alanine aminotransferase inversely correlated with serum CP activity (P = .0318, r = -0.4065).Serum copper homeostasis was altered in this cohort of patients with CHB. The results suggest increased oxidative stress and impaired antioxidant capability in patients with CHB, in addition to necroinflammation. These results may provide novel insights into the diagnosis and treatment of patients with CHB.

Acquisition of pro-oxidant activity of fALS-linked SOD1 mutants as revealed using circular dichroism and UV-resonance Raman spectroscopy

NASA Astrophysics Data System (ADS)

Fujimaki, Nobuhiro; Nishiya, Ken; Miura, Takashi; Nakabayashi, Takakazu

2016-11-01

The acquisition of pro-oxidant activity of the mutated form of human Cu, Zn-superoxide dismutase (SOD1) has been investigated to clarify the relationship between mutations in SOD1 and the pathogenesis of amyotrophic lateral sclerosis (ALS). Ala4 → Val (A4V) and Gly93 → Ala (G93A) mutants, which are representative ALS-linked SOD1 mutants, have been found to exhibit both the denaturation and the gain of pro-oxidant activity after incubation in the apo-form at a physiological condition of 37 °C and pH 7.4 and the rebinding of Cu2+. These characteristics are similar to those previously reported for the His43 → Arg (H43R) mutant. UV-resonance Raman spectra indicated that the coordination structure of the Cu-binding site catalyzing the oxidation reaction is the same among the denatured A4V, G93A, and H43R. Since wild-type SOD1 does not exhibit the denaturation in its apo-form at 37 °C and pH 7.4, the instability of the protein structure due to mutation can be considered as a significant factor that induces the denaturation and the subsequent pro-oxidant activity.