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Sample records for copper binding components

  1. Metal binding by food components

    DEFF Research Database (Denmark)

    Tang, Ning

    For calcium binding: Electrochemical method (calcium ion selective electrode) combined with quantum mechanical calculations (density functional theory) were used to investigate the calcium binding affinity of the amino acids and small glycine peptides. The effects of the ionic strength and p......, synergistic effect in calcium binding was found for the small glycine peptide rather than amino acids mixtures with the enhanced driving force up to -6 kJ/mol. Such study provides useful information for the future development of calcium supplements. For zinc binding: Isothermal titration calorimetry...... titration calorimetry and quantum mechanical calculations. This is due to the zinc binding affinity of the relatively softer ligands (investigated food components) will become much stronger than citrate or phytate when they present together in aqueous solution. This mechanism indicates these food components...

  2. A Plasmodium falciparum copper-binding membrane protein with copper transport motifs

    Directory of Open Access Journals (Sweden)

    Choveaux David L

    2012-11-01

    Full Text Available Abstract Background Copper is an essential catalytic co-factor for metabolically important cellular enzymes, such as cytochrome-c oxidase. Eukaryotic cells acquire copper through a copper transport protein and distribute intracellular copper using molecular chaperones. The copper chelator, neocuproine, inhibits Plasmodium falciparum ring-to-trophozoite transition in vitro, indicating a copper requirement for malaria parasite development. How the malaria parasite acquires or secretes copper still remains to be fully elucidated. Methods PlasmoDB was searched for sequences corresponding to candidate P. falciparum copper-requiring proteins. The amino terminal domain of a putative P. falciparum copper transport protein was cloned and expressed as a maltose binding fusion protein. The copper binding ability of this protein was examined. Copper transport protein-specific anti-peptide antibodies were generated in chickens and used to establish native protein localization in P. falciparum parasites by immunofluorescence microscopy. Results Six P. falciparum copper-requiring protein orthologs and a candidate P. falciparum copper transport protein (PF14_0369, containing characteristic copper transport protein features, were identified in PlasmoDB. The recombinant amino terminal domain of the transport protein bound reduced copper in vitro and within Escherichia coli cells during recombinant expression. Immunolocalization studies tracked the copper binding protein translocating from the erythrocyte plasma membrane in early ring stage to a parasite membrane as the parasites developed to schizonts. The protein appears to be a PEXEL-negative membrane protein. Conclusion Plasmodium falciparum parasites express a native protein with copper transporter characteristics that binds copper in vitro. Localization of the protein to the erythrocyte and parasite plasma membranes could provide a mechanism for the delivery of novel anti-malarial compounds.

  3. Cloning and expression analysis of a blue copper- binding protein ...

    African Journals Online (AJOL)

    Jane

    2011-07-20

    Jul 20, 2011 ... Full Length Research Paper. Cloning and expression analysis of a blue copper- binding protein gene from Dasypyrum Villosum. Huagang He1*, Shanying Zhu1, Wenbing Wang1, Tongde Bie2 and Peidu Chen3. 1Jiangsu University. Zhenjiang 212013, P. R. China. 2Yangzhou Academy of Agricultural ...

  4. Cooperative binding of copper(I) to the metal binding domains in Menkes disease protein

    DEFF Research Database (Denmark)

    Jensen, P Y; Bonander, N; Møller, L B

    1999-01-01

    spectroscopy, and their copper(I) binding properties have been determined. Structure prediction derived from far-UV CD indicates that the secondary structure is similar in the three proteins and dominated by beta-sheet. The tryptophan fluorescence maximum is blue-shifted in the constructs containing two...... and six MBDs relative to the monomer, suggesting more structurally buried tryptophan(s), compared to the single MBD construct. Copper(I) binding has been studied by equilibrium dialysis under anaerobic conditions. We show that the copper(I) binding to constructs containing two and six domains...... is cooperative, with Hill coefficients of 1.5 and 4, respectively. The apparent affinities are described by K(0.5), determined to be 65 microM and 19 microM for constructs containing two and six domains, respectively. Our data reveal a unique regulation of Menkes protein upon a change in copper(I) concentration...

  5. Protein-folding location can regulate manganese-binding versus copper- or zinc-binding.

    Science.gov (United States)

    Tottey, Steve; Waldron, Kevin J; Firbank, Susan J; Reale, Brian; Bessant, Conrad; Sato, Katsuko; Cheek, Timothy R; Gray, Joe; Banfield, Mark J; Dennison, Christopher; Robinson, Nigel J

    2008-10-23

    Metals are needed by at least one-quarter of all proteins. Although metallochaperones insert the correct metal into some proteins, they have not been found for the vast majority, and the view is that most metalloproteins acquire their metals directly from cellular pools. However, some metals form more stable complexes with proteins than do others. For instance, as described in the Irving-Williams series, Cu(2+) and Zn(2+) typically form more stable complexes than Mn(2+). Thus it is unclear what cellular mechanisms manage metal acquisition by most nascent proteins. To investigate this question, we identified the most abundant Cu(2+)-protein, CucA (Cu(2+)-cupin A), and the most abundant Mn(2+)-protein, MncA (Mn(2+)-cupin A), in the periplasm of the cyanobacterium Synechocystis PCC 6803. Each of these newly identified proteins binds its respective metal via identical ligands within a cupin fold. Consistent with the Irving-Williams series, MncA only binds Mn(2+) after folding in solutions containing at least a 10(4) times molar excess of Mn(2+) over Cu(2+) or Zn(2+). However once MncA has bound Mn(2+), the metal does not exchange with Cu(2+). MncA and CucA have signal peptides for different export pathways into the periplasm, Tat and Sec respectively. Export by the Tat pathway allows MncA to fold in the cytoplasm, which contains only tightly bound copper or Zn(2+) (refs 10-12) but micromolar Mn(2+) (ref. 13). In contrast, CucA folds in the periplasm to acquire Cu(2+). These results reveal a mechanism whereby the compartment in which a protein folds overrides its binding preference to control its metal content. They explain why the cytoplasm must contain only tightly bound and buffered copper and Zn(2+).

  6. Methanobactin: a copper binding compound having antibiotic and antioxidant activity isolated from methanotrophic bacteria

    Science.gov (United States)

    DiSpirito, Alan A [Ames, IA; Zahn, James A [Harbor Beach, MI; Graham, David W [Lawrence, KS; Kim, Hyung J [St. Paul, MN; Alterman, Michail [Lawrence, KS; Larive, Cynthia [Lawrence, KS

    2007-04-03

    A means and method for treating bacterial infection, providing antioxidant activity, and chelating copper using a copper binding compound produced by methanotrophic bacteria is described. The compound, known as methanobactin, is the first of a new class of antibiotics having gram-positive activity. Methanobactin has been sequenced, and its structural formula determined.

  7. The copper binding properties of metformin - QCM-D, XPS and nanobead agglomeration

    DEFF Research Database (Denmark)

    Quan, Xueling; Uddin, Rokon; Heiskanen, Arto

    2015-01-01

    Study of the copper binding properties of metformin is important for revealing its mechanism of action as a first-line type-2 diabetes drug. A quantitative investigation of interactions between metformin and l-cysteine-copper complexes was performed. The results suggest that metformin could inter...

  8. Neurokinin B and serum albumin limit copper binding to mammalian gonadotropin releasing hormone.

    Science.gov (United States)

    Gul, Ahmad Samir; Tran, Kevin K; Jones, Christopher E

    2018-02-26

    Gonadotropin releasing hormone (GnRH) triggers secretion of luteinizing hormone and follicle stimulating hormone from gonadotropic cells in the anterior pituitary gland. GnRH is able to bind copper, and both in vitro and in vivo studies have suggested that the copper-GnRH complex is more potent at triggering gonadotropin release than GnRH alone. However, it remains unclear whether copper-GnRH is the active species in vivo. To explore this we have estimated the GnRH-copper affinity and have examined whether GnRH remains copper-bound in the presence of serum albumin and the neuropeptide neurokinin B, both copper-binding proteins that GnRH will encounter in vivo. We show that GnRH has a copper dissociation constant of ∼0.9 × 10 -9  M, however serum albumin and neurokinin B can extract metal from the copper-GnRH complex. It is therefore unlikely that a copper-GnRH complex will survive transit through the pituitary portal circulation and that any effect of copper must occur outside the bloodstream in the absence of neurokinin B. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. The Methylococcus capsulatus (Bath secreted protein, MopE*, binds both reduced and oxidized copper.

    Directory of Open Access Journals (Sweden)

    Thomas Ve

    Full Text Available Under copper limiting growth conditions the methanotrophic bacterium Methylococcus capsulatus (Bath secrets essentially only one protein, MopE*, to the medium. MopE* is a copper-binding protein whose structure has been determined by X-ray crystallography. The structure of MopE* revealed a unique high affinity copper binding site consisting of two histidine imidazoles and one kynurenine, the latter an oxidation product of Trp130. In this study, we demonstrate that the copper ion coordinated by this strong binding site is in the Cu(I state when MopE* is isolated from the growth medium of M. capsulatus. The conclusion is based on X-ray Near Edge Absorption spectroscopy (XANES, and Electron Paramagnetic Resonance (EPR studies. EPR analyses demonstrated that MopE*, in addition to the strong copper-binding site, also binds Cu(II at two weaker binding sites. Both Cu(II binding sites have properties typical of non-blue type II Cu (II centres, and the strongest of the two Cu(II sites is characterised by a relative high hyperfine coupling of copper (A(|| =20 mT. Immobilized metal affinity chromatography binding studies suggests that residues in the N-terminal part of MopE* are involved in forming binding site(s for Cu(II ions. Our results support the hypothesis that MopE plays an important role in copper uptake, possibly making use of both its high (Cu(I and low Cu(II affinity properties.

  10. Polyethyleneimine anchored copper(II) complexes: synthesis, characterization, in vitro DNA binding studies and cytotoxicity studies.

    Science.gov (United States)

    Lakshmipraba, Jagadeesan; Arunachalam, Sankaralingam; Riyasdeen, Anvarbatcha; Dhivya, Rajakumar; Akbarsha, Mohammad Abdulkader

    2015-01-01

    The water soluble polyethyleneimine-copper(II) complexes, [Cu(phen)(L-tyr)BPEI]ClO4 (where phen=1,10-phenanthroline, L-tyr=L-tyrosine and BPEI=branched polyethyleneimine) with various degree of copper(II) complex units in the polymer chain were synthesized and characterized by elemental analysis and electronic, FT-IR, EPR spectroscopic techniques. The binding of these complexes with CT-DNA was studied using UV-visible absorption titration, thermal denaturation, emission, circular dichroism spectroscopy and cyclic voltammetric methods. The changes observed in the physicochemcial properties indicated that the binding between the polymer-copper complexes and DNA was mostly through electrostatic mode of binding. Among these complexes, the polymer-copper(II) complex with the highest degrees of copper(II) complex units (higher degrees of coordination) showed higher binding constant than those with lower copper(II) complex units (lower degrees of coordination) complexes. The complex with the highest number of metal centre bound strongly due to the cooperative binding effect. Therefore, anticancer study was carried out using this complex. The cytotoxic activity for this complex on MCF-7 breast cancer cell line was determined adopting MTT assay, acridine orange/ethidium bromide (AO/EB) staining and comet assay techniques, which revealed that the cells were committed to specific mode of cell death either apoptosis or necrosis. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Ligand-binding sites in human serum amyloid P component

    DEFF Research Database (Denmark)

    Heegaard, N.H.H.; Heegaard, Peter M. H.; Roepstorff, P.

    1996-01-01

    Amyloid P component (AP) is a naturally occurring glycoprotein that is found in serum and basement membranes, AP is also a component of all types of amyloid, including that found in individuals who suffer from Alzheimer's disease and Down's syndrome. Because AP has been found to bind strongly...

  12. Binding abilities of copper to phospholipids and transport of oxalate

    Czech Academy of Sciences Publication Activity Database

    Jaklová Dytrtová, Jana; Jakl, M.; Nováková, Kateřina; Navrátil, Tomáš; Šádek, Vojtěch

    2015-01-01

    Roč. 146, č. 5 (2015), s. 831-837 ISSN 0026-9247 R&D Projects: GA ČR GP13-21409P; GA ČR(CZ) GAP208/12/1645 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : copper cations * dipalmitoylphosphatidylcholine (lecithin) * ESI-MS * impedance spectroscopy * oxalic acid * voltammetry * membrane Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.131, year: 2015

  13. Investigation of the Copper Binding Site And the Role of Histidine As a Ligand in Riboflavin Binding Protein

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.R.; Bencze, K.Z.; Russ, K.A.; Wasiukanis, K.; Benore-Parsons, M.; Stemmler, T.L.

    2009-05-26

    Riboflavin Binding Protein (RBP) binds copper in a 1:1 molar ratio, forming a distinct well-ordered type II site. The nature of this site has been examined using X-ray absorption and pulsed electron paramagnetic resonance (EPR) spectroscopies, revealing a four coordinate oxygen/nitrogen rich environment. On the basis of analysis of the Cambridge Structural Database, the average protein bound copper-ligand bond length of 1.96 {angstrom}, obtained by extended x-ray absorption fine structure (EXAFS), is consistent with four coordinate Cu(I) and Cu(II) models that utilize mixed oxygen and nitrogen ligand distributions. These data suggest a Cu-O{sub 3}N coordination state for copper bound to RBP. While pulsed EPR studies including hyperfine sublevel correlation spectroscopy and electron nuclear double resonance show clear spectroscopic evidence for a histidine bound to the copper, inclusion of a histidine in the EXAFS simulation did not lead to any significant improvement in the fit.

  14. Protection of tobacco cells from oxidative copper toxicity by catalytically active metal-binding DNA oligomers.

    Science.gov (United States)

    Iwase, Junichiro; Furukawa, Hiroka; Hiramatsu, Takuya; Bouteau, François; Mancuso, Stefano; Tanaka, Kenichiro; Okazaki, Toshihiko; Kawano, Tomonori

    2014-03-01

    The impact of copper ions on the oxidative and calcium signal transductions, leading to cell death in plant cells, have been documented. Copper induces a series of biological and chemical reactions in plant cells including the oxidative burst reflecting the production of reactive oxygen species and the stimulation of calcium channel opening allowing a transient increase in cytosolic calcium concentrations. These early events, completed within a few minutes after the contact with copper, are known to trigger the development of cell death. The effects of DNA fragments with copper-binding motifs as novel plant cell-protecting agents were assessed using cell suspension cultures of transgenic tobacco (Nicotiana tabacum L., cell line BY-2) expressing the aequorin gene. The addition of GC-rich double-stranded DNA fragments, prior to the addition of copper ions, effectively blocked both the copper-induced calcium influx and cell death. In addition, the DNA-Cu complex examined was shown to possess superoxide-scavenging catalytic activity, suggesting that DNA-mediated protection of the cells from copper toxicity is due to the removal of superoxide. Lastly, a possible mechanism of DNA-Cu interaction and future applications of these DNA fragments in the protection of plant roots from metal toxicity or in aid of phyto-remediation processes are discussed.

  15. Application of the NICADonnan model for proton, copper and uranyl binding to humic acid

    NARCIS (Netherlands)

    Saito, T.; Nagasaki, S.; Tanaka, S.; Koopal, L.K.

    2004-01-01

    Humic acids are natural organic materials that play an important role in the migration of heavy metal and actinide ions in aquatic and soil systems. In the present study, the binding of protons, copper ions and uranyl ions to the purified Aldrich humic acid (PAHA) is investigated and the results are

  16. The E1 copper binding domain of full-length amyloid precursor protein mitigates copper-induced growth inhibition in brain metastatic prostate cancer DU145 cells

    Energy Technology Data Exchange (ETDEWEB)

    Gough, Mallory, E-mail: m.gough1@lancaster.ac.uk; Blanthorn-Hazell, Sophee, E-mail: s.blanthorn-hazell@lancaster.ac.uk; Delury, Craig, E-mail: c.delury@lancaster.ac.uk; Parkin, Edward, E-mail: e.parkin@lancaster.ac.uk

    2014-10-31

    Highlights: • Copper levels are elevated in the tumour microenvironment. • APP mitigates copper-induced growth inhibition of DU145 prostate cancer (PCa) cells. • The APP intracellular domain is a prerequisite; soluble forms have no effect. • The E1 CuBD of APP is also a prerequisite. • APP copper binding potentially mitigates copper-induced PCa cell growth inhibition. - Abstract: Copper plays an important role in the aetiology and growth of tumours and levels of the metal are increased in the serum and tumour tissue of patients affected by a range of cancers including prostate cancer (PCa). The molecular mechanisms that enable cancer cells to proliferate in the presence of elevated copper levels are, therefore, of key importance in our understanding of tumour growth progression. In the current study, we have examined the role played by the amyloid precursor protein (APP) in mitigating copper-induced growth inhibition of the PCa cell line, DU145. A range of APP molecular constructs were stably over-expressed in DU145 cells and their effects on cell proliferation in the presence of copper were monitored. Our results show that endogenous APP expression was induced by sub-toxic copper concentrations in DU145 cells and over-expression of the wild-type protein was able to mitigate copper-induced growth inhibition via a mechanism involving the cytosolic and E1 copper binding domains of the full-length protein. APP likely represents one of a range of copper binding proteins that PCa cells employ in order to ensure efficient proliferation despite elevated concentrations of the metal within the tumour microenvironment. Targeting the expression of such proteins may contribute to therapeutic strategies for the treatment of cancers.

  17. Binding characteristics of copper and cadmium by cyanobacterium Spirulina platensis

    Energy Technology Data Exchange (ETDEWEB)

    Fang Linchuan [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Zhou Chen; Cai Peng [Key Laboratory of Subtropical Agricultural Resources and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Chen Wenli [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Rong Xingmin; Dai Ke; Liang Wei [Key Laboratory of Subtropical Agricultural Resources and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China); Gu Jidong [Department of Ecology and Biodiversity, University of Hong Kong, Pokfulam Road, Hong Kong (Hong Kong); Huang Qiaoyun, E-mail: qyhuang@mail.hzau.edu.cn [State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan 430070 (China); Key Laboratory of Subtropical Agricultural Resources and Environment, Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (China)

    2011-06-15

    Highlights: {yields} The carboxyl groups play a vital role in the binding of Cu(II) and Cd(II) to S. platensis cells. {yields} Ion exchange and complexation are the dominating mechanism for Cu(II) and Cd(II) adsorption. {yields} XAFS analysis provided evidence for the inner-sphere complexation of Cu by carboxyl ligands and showed that Cu is complexed by two 5-membered chelate rings on S. platensis surface. - Abstract: Cyanobacteria are promising biosorbent for heavy metals in bioremediation. Although sequestration of metals by cyanobacteria is known, the actual mechanisms and ligands involved are not very well understood. The binding characteristics of Cu(II) and Cd(II) by the cyanobacterium Spirulina platensis were investigated using a combination of chemical modifications, batch adsorption experiments, Fourier transform infrared (FTIR) spectroscopy and X-ray absorption fine structure (XAFS) spectroscopy. A significant increase in Cu(II) and Cd(II) binding was observed in the range of pH 3.5-5.0. Dramatical decrease in adsorption of Cu(II) and Cd(II) was observed after methanol esterification of the nonliving cells demonstrating that carboxyl functional groups play an important role in the binding of metals by S. platensis. The desorption rate of Cu(II) and Cd(II) from S. platensis surface was 72.7-80.7% and 53.7-58.0% by EDTA and NH{sub 4}NO{sub 3}, respectively, indicating that ion exchange and complexation are the dominating mechanisms for Cu(II) and Cd(II) adsorption. XAFS analysis provided further evidence on the inner-sphere complexation of Cu by carboxyl ligands and showed that Cu is complexed by two 5-membered chelate rings on S. platensis surface.

  18. Copper binding ligands: production by marine plankton and characterization by ESI-MS

    Science.gov (United States)

    Orians, K.; Ross, A.; Lawrence, M.; Ikonomou, M.

    2003-04-01

    Organic complexation affects the bioavailability and distribution of copper in the surface ocean. The cyanobacterium Synechococcus sp. PCC 7002 was cultured in the lab and subjected to near-toxic Cu concentrations. Strong Cu-binding ligands were produced under these conditions, as found for other species of Synechococcus. The copper-binding ligand produced had a log K'cond. (log conditional stability constant) of 12.2, similar to the natural ligands found in the surface ocean. The amount of ligand produced was proportional to the amount of copper present. Isolation and concentration of these compounds for characterization by electrospray mass spectrometry (ESI-MS) provides information about the structure of the organic ligands and their metal-ion complexes. Using model ligands, we'll show that ligands can be characterized by ESI-MS and that the location of the copper binding site can be determined in complex molecules. We'll also present results of copper-complexing ligands extracted from the coastal waters of British Columbia. Ligand concentrations are higher at low salinity and in surface waters, indicating that these ligands are produced in surface waters and/or delivered to the region via the Fraser River. Analysis of the extracts with highest UV absorbance identified two Cu2+ ligands of molecular weight 259 and 264. The mass and isotopic distributions are consistent with dipeptides and tripeptides containing two metal-binding amino groups. This result is consistent with the findings of other studies attempting to characterize Cu2+ ligands in seawater. The structure of the identified ligand is similar to that of rhodotorulic acid (a microbial siderophore), glutathione, and phytochelatins, indicating that small peptides and related compounds can act as strong, specific metal chelators in natural waters

  19. Applicability of copper alloys for DEMO high heat flux components

    Science.gov (United States)

    Zinkle, Steven J.

    2016-02-01

    The current state of knowledge of the mechanical and thermal properties of high-strength, high conductivity Cu alloys relevant for fusion energy high heat flux applications is reviewed, including effects of thermomechanical and joining processes and neutron irradiation on precipitation- or dispersion-strengthened CuCrZr, Cu-Al2O3, CuNiBe, CuNiSiCr and CuCrNb (GRCop-84). The prospects for designing improved versions of wrought copper alloys and for utilizing advanced fabrication processes such as additive manufacturing based on electron beam and laser consolidation methods are discussed. The importance of developing improved structural materials design criteria is also noted.

  20. Carbon-carbon composite and copper-composite bond damages for high flux component controlled fusion

    International Nuclear Information System (INIS)

    Chevet, G.

    2010-01-01

    Plasma facing components constitute the first wall in contact with plasma in fusion machines such as Tore Supra and ITER. These components have to sustain high heat flux and consequently elevated temperatures. They are made up of an armour material, the carbon-carbon composite, a heat sink structure material, the copper chromium zirconium, and a material, the OFHC copper, which is used as a compliant layer between the carbon-carbon composite and the copper chromium zirconium. Using different materials leads to the apparition of strong residual stresses during manufacturing, because of the thermal expansion mismatch between the materials, and compromises the lasting operation of fusion machines as damage which appeared during manufacturing may propagate. The objective of this study is to understand the damage mechanisms of the carbon-carbon composite and the composite-copper bond under solicitations that plasma facing components may suffer during their life. The mechanical behaviours of carbon-carbon composite and composite-copper bond were studied in order to define the most suitable models to describe these behaviours. With these models, thermomechanical calculations were performed on plasma facing components with the finite element code Cast3M. The manufacturing of the components induces high stresses which damage the carbon-carbon composite and the composite-copper bond. The damage propagates during the cooling down to room temperature and not under heat flux. Alternative geometries for the plasma facing components were studied to reduce damage. The relation between the damage of the carbon-carbon composite and its thermal conductivity was also demonstrated. (author) [fr

  1. DNA binding and cleavage studies of copper(II) complexes with 2'-deoxyadenosine modified histidine moiety.

    Science.gov (United States)

    Borowska, Justyna; Sierant, Malgorzata; Sochacka, Elzbieta; Sanna, Daniele; Lodyga-Chruscinska, Elzbieta

    2015-09-01

    This work is focused on the study of DNA binding and cleavage properties of 2'-deoxyadenosines modified with ester/amide of histidine (his(6)dA ester, his(6)dA amide) and their copper(II) complexes. To determine the coordination mode of the complex species potentiometric and spectroscopic (UV-visible, CD, EPR) studies have been performed. The analysis of electronic absorption and fluorescence spectra has been used to find the nature of the interactions between the compounds and calf thymus DNA (CT-DNA). There is significant influence of the -NH2 and -OCH3 groups on binding of the ligands or the complexes to DNA. Only amide derivative and its complex reveal intercalative ability. In the case of his(6)dA ester and Cu(II)-his(6)dA ester the main interactions can be groove binding. DNA cleavage activities of the compounds have been examined by gel electrophoresis. The copper complexes have promoted the cleavage of plasmid DNA, but none of the ligands exhibited any chemical nuclease activity. The application of different scavengers of reactive oxygen species provided a conclusion that DNA cleavage caused by copper complexes might occur via hydrolytic pathway.

  2. Copper binding to the N-terminal metal-binding sites or the CPC motif is not essential for copper-induced trafficking of the human Wilson protein (ATP7B)

    Science.gov (United States)

    Cater, Michael A.; La fontaine, Sharon; Mercer, Julian F. B.

    2006-01-01

    The Wilson protein (ATP7B) is a copper-translocating P-type ATPase that mediates the excretion of excess copper from hep-atocytes into bile. Excess copper causes the protein to traffic from the TGN (trans-Golgi network) to subapical vesicles. Using site-directed mutagenesis, mutations known or predicted to abrogate catalytic activity (copper translocation) were introduced into ATP7B and the effect of these mutations on the intracellular traf-ficking of the protein was investigated. Mutation of the critical aspartic acid residue in the phosphorylation domain (DKTGTIT) blocked copper-induced redistribution of ATP7B from the TGN, whereas mutation of the phosphatase domain [TGE (Thr-Gly-Glu)] trapped ATP7B at cytosolic vesicular compartments. Our findings demonstrate that ATP7B trafficking is regulated with its copper-translocation cycle, with cytosolic vesicular localization associated with the acyl-phosphate intermediate. In addition, mut-ation of the six N-terminal metal-binding sites and/or the trans-membrane CPC (Cys-Pro-Cys) motif did not suppress the consti-tutive vesicular localization of the ATP7B phosphatase domain mutant. These results suggested that copper co-ordination by these sites is not essential for trafficking. Importantly, copper-chelation studies with these mutants clearly demonstrated a requirement for copper in ATP7B trafficking, suggesting the presence of an additional copper-binding site(s) within the protein. The results presented in this report significantly advance our understanding of the regulatory mechanism that links copper-translocation activity with copper-induced intracellular trafficking of ATP7B, which is central to hepatic and hence systemic copper homoeostasis. PMID:16939419

  3. Azide binding to the trinuclear copper center in laccase and ascorbate oxidase

    DEFF Research Database (Denmark)

    Gromov, I; Marchesini, A; Farver, O

    1999-01-01

    Azide binding to the blue copper oxidases laccase and ascorbate oxidase (AO) was investigated by electron paramagnetic resonance (EPR) and pulsed electron-nuclear double resonance (ENDOR) spectroscopies. As the laccase : azide molar ratio decreases from 1:1 to 1:7, the intensity of the type 2 (T2...... characteristics was found in the AO : azide (1:7) sample. The g azide binding disrupts the anti-ferromagnetic coupling of the type 3 (T3) Cu(II) pair. Analysis of the position of the g ... of the protein molecules, and in the remaining part a different azide binding mode is observed. The 130 K EPR spectra of AO and laccase with azide (1:7) exhibit, in addition to an unperturbed T2 Cu(II) signal, new features in the g parallel region that are attributed to a perturbed T2 in protein molecules where...

  4. DNA binding affinity of a macrocyclic copper(II) complex: Spectroscopic and molecular docking studies.

    Science.gov (United States)

    Shahabadi, Nahid; Hakimi, Mohammad; Morovati, Teimoor; Fatahi, Navid

    2017-08-03

    The interaction of a novel macrocyclic copper(II) complex, ([CuL(ClO 4 ) 2 ] that L is 1,3,6,10,12,15-hexaazatricyclo[13.3.1.1 6,10 ]eicosane) with calf thymus DNA (ct-DNA) was investigated by various physicochemical techniques and molecular docking at simulated physiological conditions (pH = 7.4). The absorption spectra of the Cu(II) complex with ct-DNA showed a marked hyperchroism with 10 nm blue shift. The intrinsic binding constant (K b ) was determined as 1.25 × 10 4 M -1 , which is more in keeping with the groove binding with DNA. Furthermore, competitive fluorimetric studies with Hoechst33258 have shown that Cu(II) complex exhibits the ability to displace the ct-DNA-bound Hoechst33258 indicating that it binds to ct-DNA in strong competition with Hoechst33258 for the groove binding. Also, no change in the relative viscosity of ct-DNA and fluorescence intensity of ct-DNA-MB complex in the present of Cu(II) complex is another evidence to groove binding. The thermodynamic parameters are calculated by van't Hoff equation, which demonstrated that hydrogen bonds and van der Waals interactions played major roles in the binding reaction. The experimental results were in agreement with the results obtained via molecular docking study.

  5. Comparative analysis of copper alloys for the heat sink of plasma facing components in ITER

    International Nuclear Information System (INIS)

    Kalinin, G.; Matera, R.

    1998-01-01

    Due to their excellent thermal conductivity, copper alloys are the obvious choice for the heat sink of the high heat flux (HHF) components in ITER. In addition to thermal conductivity, other properties have to be taken into consideration for the final selection of the alloy system and of the specific grade. For comparison, the following parameters have been taken into account: tensile strength and ductility, fracture toughness, allowable strain for fatigue endurance of 10 4 cycles, thermal stress factor, and thermal conductivity. An assessment is made of the proposed copper alloys to be used in ITER, precipitation hardened copper alloys (CuCrZr, CuNiBe, CuNiCrSi) and dispersion hardened copper (CuAl25). The analysis shows that CuAl25 is the most reasonable choice for the HHF components of the primary wall due to heat resistance and satisfactory design allowable (strength, fatigue and fracture toughness), CuCrZr is proposed for the divertor where the fatigue and resistance to fracture are most critical. (orig.)

  6. Synthesis, characterization, DNA binding and cleavage studies of mixed-ligand copper (II complexes

    Directory of Open Access Journals (Sweden)

    M. Sunita

    2017-05-01

    Full Text Available New two copper complexes of type [Cu(Bzimpy(LH2O]SO4 (where L = 2,2′ bipyridine (bpy, and ethylene diamine (en, Bzimpy = 2,6-bis(benzimidazole-2ylpyridine have been synthesized and characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, mass, IR, electronic and EPR spectral studies. Based on elemental and spectral studies six coordinated geometries were assigned to the two complexes. DNA-binding properties of these metal complexes were investigated using absorption spectroscopy, fluorescence spectroscopy, viscosity measurements and thermal denaturation methods. Experimental studies suggest that the complexes bind to DNA through intercalation. These complexes also promote the cleavage of plasmid pBR322, in the presence of H2O2.

  7. Enantiopure copper(II) complex of natural product rosin derivative: DNA binding, DNA cleavage and cytotoxicity.

    Science.gov (United States)

    Fei, Bao-Li; Yin, Bin; Li, Dong-Dong; Xu, Wu-Shuang; Lu, Yang

    2016-12-01

    To develop chiral anticancer drug candidates for molecular target DNA, the synthesis and characterization of a novel enantiomerically pure copper(II) complex [Cu 1 Cl 2 ] (2) of an optically pure ligand N-(pyridin-2-ylmethylene) dehydroabietylamine (1) was carried out. The coordination geometry of the copper center is a distorted square-planar arrangement. The interactions of 1 and 2 with salmon sperm DNA were investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. All the results reveal that 1 and 2 interacted with DNA through intercalation and 2 exhibited a higher DNA binding ability. Further, 1 and 2 could cleave supercoiled pBR322 DNA by single strand and 2 displayed stronger cleavage ability in the presence of ascorbic acid. In vitro cytotoxicity of 1 and 2 against HeLa, SiHa, HepG-2 and A431 cancer cell lines was studied using CCK-8 assay. The results indicate that 2 had a superior cytotoxicity than 1 and the widely used drug cisplatin under identical conditions. Flow cytometry analysis demonstrates 2 produced death of HeLa cancer cells through an apoptotic pathway. Cell cycle analysis shows that 2 mainly arrested HeLa cells at the S phase. A novel enantiomerically pure copper(II) complex [Cu 1 Cl 2 ] (2) of an optically pure ligand N-(pyridin-2-ylmethylene) dehydroabietylamine (1), based on natural product rosin has been synthesized. 2 has the potential to act as effective anticancer drug.

  8. Determinants for simultaneous binding of copper and platinum to human chaperone Atox1: hitchhiking not hijacking.

    Directory of Open Access Journals (Sweden)

    Maria E Palm-Espling

    Full Text Available Cisplatin (CisPt is an anticancer agent that has been used for decades to treat a variety of cancers. CisPt treatment causes many side effects due to interactions with proteins that detoxify the drug before reaching the DNA. One key player in CisPt resistance is the cellular copper-transport system involving the uptake protein Ctr1, the cytoplasmic chaperone Atox1 and the secretory path ATP7A/B proteins. CisPt has been shown to bind to ATP7B, resulting in vesicle sequestering of the drug. In addition, we and others showed that the apo-form of Atox1 could interact with CisPt in vitro and in vivo. Since the function of Atox1 is to transport copper (Cu ions, it is important to assess how CisPt binding depends on Cu-loading of Atox1. Surprisingly, we recently found that CisPt interacted with Cu-loaded Atox1 in vitro at a position near the Cu site such that unique spectroscopic features appeared. Here, we identify the binding site for CisPt in the Cu-loaded form of Atox1 using strategic variants and a combination of spectroscopic and chromatographic methods. We directly prove that both metals can bind simultaneously and that the unique spectroscopic signals originate from an Atox1 monomer species. Both Cys in the Cu-site (Cys12, Cys15 are needed to form the di-metal complex, but not Cys41. Removing Met10 in the conserved metal-binding motif makes the loop more floppy and, despite metal binding, there are no metal-metal electronic transitions. In silico geometry minimizations provide an energetically favorable model of a tentative ternary Cu-Pt-Atox1 complex. Finally, we demonstrate that Atox1 can deliver CisPt to the fourth metal binding domain 4 of ATP7B (WD4, indicative of a possible drug detoxification mechanism.

  9. Effects of copper ions on DNA binding and cytotoxic activity of a chiral salicylidene Schiff base.

    Science.gov (United States)

    Fei, Bao-Li; Xu, Wu-Shuang; Tao, Hui-Wen; Li, Wen; Zhang, Yu; Long, Jian-Ying; Liu, Qing-Bo; Xia, Bing; Sun, Wei-Yin

    2014-03-05

    A chiral Schiff base HL N-(5-bromo-salicylaldehyde)dehydroabietylamine (1) and its chiral dinuclear copper complex [Cu2L4]·4DMF (2) have been synthesized and fully characterized. The interactions of 1 and 2 with salmon sperm DNA have been investigated by viscosity measurements, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral (Kb=3.30 × 10(5)M(-)(1) (1), 6.63 × 10(5)M(-)(1)(2)), emission spectral (Ksv=7.58 × 10(3)M(-)(1) (1), 1.52 × 10(4)M(-)(1) (2)), and viscosity measurements reveal that 1 and 2 interact with DNA through intercalation and 2 exhibits a higher DNA binding ability. In addition, CD study indicates 2 cause a more evident perturbation on the base stacking and helicity of B-DNA upon binding to it. In fluorimetric studies, the enthalpy (ΔH>0) and entropy (ΔS>0) changes of the reactions between the compounds with DNA demonstrate hydrophobic interactions. 1 and 2 were also screened for their cytotoxic ability and 2 demonstrates higher growth inhibition of the selected cancer cells at concentration of 50 μM, this result is identical with their DNA binding ability order. All the experimental results show that the involvement of Cu (II) centers has some interesting effect on DNA binding ability and cytotoxicity of the chiral Schiff base. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Development and tests of molybdenum armored copper components for MITICA ion source

    Energy Technology Data Exchange (ETDEWEB)

    Pavei, Mauro, E-mail: mauro.pavei@igi.cnr.it; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo [Consorzio RFX, Corso Stati Uniti, 4, I-35127 Padova (Italy); Böswirth, Bernd; Greuner, Henri [Max-Planck-Institut für Plasmaphysik, Boltzmannstrasse 2, D-85748 Garching (Germany)

    2016-02-15

    In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

  11. Development and tests of molybdenum armored copper components for MITICA ion source

    Science.gov (United States)

    Pavei, Mauro; Böswirth, Bernd; Greuner, Henri; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo

    2016-02-01

    In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results.

  12. Development and tests of molybdenum armored copper components for MITICA ion source

    International Nuclear Information System (INIS)

    Pavei, Mauro; Marcuzzi, Diego; Rizzolo, Andrea; Valente, Matteo; Böswirth, Bernd; Greuner, Henri

    2016-01-01

    In order to prevent detrimental material erosion of components impinged by back-streaming positive D or H ions in the megavolt ITER injector and concept advancement beam source, a solution based on explosion bonding technique has been identified for producing a 1 mm thick molybdenum armour layer on copper substrate, compatible with ITER requirements. Prototypes have been recently manufactured and tested in the high heat flux test facility Garching Large Divertor Sample Test Facility (GLADIS) to check the capability of the molybdenum-copper interface to withstand several thermal shock cycles at high power density. This paper presents both the numerical fluid-dynamic analyses of the prototypes simulating the test conditions in GLADIS as well as the experimental results

  13. Synthesis, characterization, DNA-binding and cleavage studies of polypyridyl copper(II) complexes

    Science.gov (United States)

    Gubendran, Ammavasi; Rajesh, Jegathalaprathaban; Anitha, Kandasamy; Athappan, Periyakaruppan

    2014-10-01

    Six new mixed-ligand copper(II) complexes were synthesized namely [Cu(phen)2OAc]ClO4ṡH2O(1), [Cu(bpy)2OAc]ClO4ṡH2O(2), [Cu(o-ampacac)(phen)]ClO4(3), [Cu(o-ampbzac)(phen)]ClO4(4), [Cu(o-ampacac)(bpy)]ClO4(5), and [Cu(o-ampbzac)(bpy)]ClO4(6) (phen = 1,10-phenanthroline, bpy = 2, 2‧-bipyridine, o-ampacac = (Z)-4-(2-hydroxylamino)pent-3-ene-2-one,o-ampbzac = (Z)-4-(2-hydroxylamino)-4-phenylbut-3-ene-2-one)and characterized by UV-Vis, IR, EPR and cyclic voltammetry. Ligands were characterized by NMR spectra. Single crystal X-ray studies of the complex 1 shows Cu(II) ions are located in a highly distorted octahedral environment. Absorption spectral studies reveal that the complexes 1-6 exhibit hypochromicity during the interaction with DNA and binding constant values derived from spectral and electrochemical studies indicate that complexes 1, 2 and 3 bind strongly with DNA possibly by an intercalative mode. Electrochemical studies reveal that the complexes 1-4 prefer to bind with DNA in Cu(I) rather than Cu(II) form. The shift in the formal potentials E1/2 and CD spectral studies suggest groove or electrostatic binding mode for the complexes 4-6. Complex 1 can cleave supercoiled (SC) pUC18 DNA efficiently into nicked form II under photolytic conditions and into an open circular form (form II) and linear form (form III) in the presence of H2O2 at pH 8.0 and 37 °C, while the complex 2 does not cleave DNA under similar conditions.

  14. Analysis of leukocyte binding to depletion filters: role of passive binding, interaction with platelets, and plasma components.

    Science.gov (United States)

    Henschler, R; Rüster, B; Steimle, A; Hansmann, H L; Walker, W; Montag, T; Seifried, E

    2005-08-01

    Since limited knowledge exists on the mechanisms which regulate cell binding to leukocyte removal filter surfaces, we investigated the binding patterns of leukocytes to individual layers of leukocyte depletion filters. After passage of 1 unit of whole blood, blotting of isolated filter layers on glass slides or elution of cells from filter layers revealed that most leukocytes were located within the first 10 of a total of 28 filter layers, peaking at layers 6 to 8, with granulocytes binding on average to earlier filter layers than lymphocytes. Leukocytes preincubated with inhibitors of actin activation showed unchanged distribution between filter layers, suggesting that cytoskeletal activation does not significantly contribute to their binding. When leukocytes were directly incubated with single filter layers, binding of up to 30% of input cells was recorded in the absence of Ca(2+). Immunohistological analyses showed colocalization of platelets and leukocytes, with co-clustering of platelets and leukocytes. Monocytes and to some degree lymphocytes but not granulocytes competed with platelets for filter binding. Precoating of filter layers with individual plasma components showed that hyaluronic acid, plasma type fibronectin, and fibrinogen all increased the binding of leukocytes compared with albumin coating. In conclusion, leukocytes can bind passively to filters in a process which does not require Ca(2+), which is independent of cytoskeletal activation and which may depend on individual plasma components. These results are of importance when new selective cell enrichment or depletion strategies through specific filters are envisaged.

  15. Azide binding to the trinuclear copper center in laccase and ascorbate oxidase

    DEFF Research Database (Denmark)

    Gromov, I; Marchesini, A; Farver, O

    1999-01-01

    Azide binding to the blue copper oxidases laccase and ascorbate oxidase (AO) was investigated by electron paramagnetic resonance (EPR) and pulsed electron-nuclear double resonance (ENDOR) spectroscopies. As the laccase : azide molar ratio decreases from 1:1 to 1:7, the intensity of the type 2 (T2...... that the distance between the dipolar coupled Cu(II) pair is shorter in laccase than in AO. The proximity of T2 Cu(II) to the S = 1 Cu(II) pair enhances its relaxation rate, reducing its signal intensity relative to that of native protein. The disruption of the T3 anti-ferromagnetic coupling occurs only in part...... of the protein molecules, and in the remaining part a different azide binding mode is observed. The 130 K EPR spectra of AO and laccase with azide (1:7) exhibit, in addition to an unperturbed T2 Cu(II) signal, new features in the g parallel region that are attributed to a perturbed T2 in protein molecules where...

  16. Synthesis and structure elucidation of a copper(II) Schiff-base complex: in vitro DNA binding, pBR322 plasmid cleavage and HSA binding studies.

    Science.gov (United States)

    Tabassum, Sartaj; Ahmad, Musheer; Afzal, Mohd; Zaki, Mehvash; Bharadwaj, Parimal K

    2014-11-01

    New copper(II) complex with Schiff base ligand 4-[(2-Hydroxy-3-methoxy-benzylidene)-amino]-benzoic acid (H₂L) was synthesized and characterized by spectroscopic and analytical and single crystal X-ray diffraction studies which revealed that the complex 1 exist in a distorted octahedral environment. In vitro CT-DNA binding studies were performed by employing different biophysical technique which indicated that the 1 strongly binds to DNA in comparison to ligand via electrostatic binding mode. Complex 1 cleaves pBR322 DNA via hydrolytic pathway and recognizes minor groove of DNA double helix. The HSA binding results showed that ligand and complex 1 has ability to quench the fluorescence emission intensity of Trp 214 residue available in the subdomain IIA of HSA. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Mechanism of uranium binding to cellular components of microorganisms. II

    International Nuclear Information System (INIS)

    Jilek, R.; Beranova, E.

    1986-01-01

    Knowledge is summed up of the mechanism of inhibition of carbohydrate metabolism by uranyl ions in yeast and bacteria. The inhibition was found of anaerobic fermentation of glucose by undisturbed yeast cells and by cell-free extract to take place at different uranyl concentrations. The course of time dependence of uranium intake by live yeast cells showed that this process is not controlled by diffusion. It is based on complex binding of uranyl to the cell surface. A more detailed study of the process has shown that even with full saturation of the cell surface with uranyl ions the anaerobic metabolism is only inhibited to 90%, the remaining 10% of the metabolism is apparently provided by a different mechanism. Other centres were discovered on the surface of the yeast cell which do not take part in the anaerobic intake of glucose but form complexes with the uranyl. Mg 2+ , Ca 2+ , Ba 2+ , Mn 2+ , Cu 2+ , Ni 2+ , Co 2+ , Fe 2+ and other bivalent cations can compete with uranyl binding to active cell centres. The most stable complex, however, is formed by the uranyl ion. A more detailed clarification of the chemical character of active centres of the cell surface was made by comparative studies of the stability of the uranyl complex with yeast cells and similar complexes of model compounds. The most stable complex bonds were found to exist in highly polymerated inorganic phosphates. (E.S.)

  18. Binding between two-component bosons in one dimension

    International Nuclear Information System (INIS)

    Tempfli, Emmerich; Zoellner, Sascha; Schmelcher, Peter

    2009-01-01

    We investigate the ground state of one-dimensional few-atom Bose-Bose mixtures under harmonic confinement throughout the crossover from weak to strong inter-species attraction. The calculations are based on the numerically exact multi-configurational time-dependent Hartree method. For repulsive components, we detail the condition for the formation of a molecular Tonks-Girardeau gas in the regime of intermediate inter-species interactions, and the formation of a molecular condensate for stronger coupling. Beyond a critical inter-species attraction, the system collapses to an overall bound state. Different pathways emerge for unequal particle numbers and intra-species interactions. In particular, for mixtures with one attractive component, this species can be viewed as an effective potential dimple in the trap center for the other, repulsive component.

  19. Ternary copper(II) complexes with amino acid chains and heterocyclic bases: DNA binding, cytotoxic and cell apoptosis induction properties.

    Science.gov (United States)

    Ma, Tieliang; Xu, Jun; Wang, Yuan; Yu, Hao; Yang, Yong; Liu, Yang; Ding, Weiliang; Zhu, Wenjiao; Chen, Ruhua; Ge, Zhijun; Tan, Yongfei; Jia, Lei; Zhu, Taofeng

    2015-03-01

    Nowadays, chemotherapy is a common means of oncology. However, it is difficult to find excellent chemotherapy drugs. Here we reported three new ternary copper(II) complexes which have potential chemotherapy characteristics with reduced Schiff base ligand and heterocyclic bases (TBHP), [Cu(phen)(TBHP)]H2O (1), [Cu(dpz)(TBHP)]H2O (2) and [Cu(dppz)(TBHP)]H2O (3) (phen=1,10-phenanthroline, dpz=dipyrido [3,2:2',3'-f]quinoxaline, dppz=dipyrido [3,2-a:2',3'-c]phenazine, H2TBHP=2-(3,5-di-tert-butyl-2-hydroxybenzylamino)-2-benzyl-acetic acid). The DNA-binding properties of the complexes were investigated by spectrometric titrations, ethidium bromide displacement experiments and viscosity measurements. The results indicated that the three complexes, especially the complex 13, can strongly bind to calf-thymus DNA (CT-DNA). The intrinsic binding constants Kb of the ternary copper(II) complexes with CT-DNA were 1.37×10(5), 1.81×10(5) and 3.21×10(5) for 1, 2 and 3 respectively. Comparative cytotoxic activities of the copper(II) complexes were also determined by 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The results showed that the ternary copper(II) complexes had significant cytotoxic activity against the human lung cancer (A549), human esophageal cancer (Eca109) and human gastric cancer (SGC7901) cell lines. Cell apoptosis were detected by AnnexinV/PI flow cytometry and by Western blotting with the protein expression of p53, Bax and Bcl-2. All the three copper complexes can effectively induce apoptosis of the three human tumor cells. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Printing Electronic Components from Copper-Infused Ink and Thermoplastic Mediums

    Science.gov (United States)

    Flowers, Patrick F.

    The demand for printable electronics has sharply increased in recent years and is projected to continue to rise. Unfortunately, electronic materials which are suitable for desired applications while being compatible with available printing techniques are still often lacking. This thesis addresses two such challenging areas. In the realm of two-dimensional ink-based printing of electronics, a major barrier to the realization of printable computers that can run programs is the lack of a solution-coatable non-volatile memory with performance metrics comparable to silicon-based devices. To address this deficiency, I developed a nonvolatile memory based on Cu-SiO2 core-shell nanowires that can be printed from solution and exhibits on-off ratios of 106, switching speeds of 50 ns, a low operating voltage of 2 V, and operates for at least 104 cycles without failure. Each of these metrics is similar to or better than Flash memory (the write speed is 20 times faster than Flash). Memory architectures based on the individual memory cells demonstrated here could enable the printing of the more complex, embedded computing devices that are expected to make up an internet of things. Recently, the exploration of three-dimensional printing techniques to fabricate electronic materials began. A suitable general-purpose conductive thermoplastic filament was not available, however. In this work I examine the current state of conductive thermoplastic filaments, including a newly-released highly conductive filament that my lab has produced which we call Electrifi. I focus on the use of dual-material fused filament fabrication (FFF) to 3D print electronic components (conductive traces, resistors, capacitors, inductors) and circuits (a fully-printed high-pass filter). The resistivity of traces printed from conductive thermoplastic filaments made with carbon-black, graphene, and copper as conductive fillers was found to be 12, 0.78, and 0.014 ohm cm, respectively, enabling the creation of

  1. Synthesis, structural characterization, cytotoxic properties and DNA binding of a dinuclear copper(II) complex.

    Science.gov (United States)

    Ferreira, B J M Leite; Brandão, P; Meireles, M; Martel, Fátima; Correia-Branco, Ana; Fernandes, Diana M; Santos, T M; Félix, V

    2016-08-01

    In this study a novel dinuclear copper(II) complex with adenine and phenanthroline has been synthesized and its structure determined by single crystal X-ray diffraction. In the dinuclear complex [Cu₂(μ-adenine)₂(phen)₂(H2O)2](NO3)4·0.5H2O (phen=1,10-phenanthroline) (1) the two Cu(II) centres exhibit a distorted square pyramidal coordination geometry linked by two nitrogen donors from adenine bridges leading to a Cu-Cu distance of 3.242(3)Å. Intramolecular and intermolecular π⋯π interactions as well as an H-bonding network were observed. The antitumor capacity of the complex has been tested in vitro against human cancer cell lines, cervical carcinoma (HeLa) and colorectal adenocarcinoma (Caco-2), by metabolic tests, using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide as reagent. The complex 1 has remarkable low IC50 values of 0.87±0.06μM (HeLa) and 0.44±0.06μM (Caco-2), when compared with values for cisplatin against the same cell lines. The interaction of complex 1 with calf thymus DNA (CT DNA) was further investigated by absorption and fluorescence spectroscopic methods. A binding constant of 5.09×10(5)M(-1) was obtained from UV-vis absorption studies. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Binding interactions between suberin monomer components and pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Olivella, M.À., E-mail: angels.olivella@udg.edu [Department of Chemical Engineering, Escola Politècnica Superior, Universitat de Girona, Maria Aurèlia Capmany, 61, 17071 Girona (Spain); Bazzicalupi, C.; Bianchi, A. [Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia, 3, 50019 Sesto Fiorentino (Italy); Río, J.C. del [Instituto de Recursos Naturales y Agrobiología de Sevilla, Consejo Superior de Investigaciones Científicas, P.O. Box 1052, 41080 Seville (Spain); Fiol, N.; Villaescusa, I. [Department of Chemical Engineering, Escola Politècnica Superior, Universitat de Girona, Maria Aurèlia Capmany, 61, 17071 Girona (Spain)

    2015-09-15

    Understanding the role of biomacromolecules and their interactions with pollutants is a key for elucidating the sorption mechanisms and making an accurate assessment of the environmental fate of pollutants. The knowledge of the sorption properties of the different constituents of these biomacromolecules may furnish a significant contribution to this purpose. Suberin is a very abundant biopolymer in higher plants. In this study, suberin monomers isolated from cork were analyzed by thermally-assisted methylation with tetramethylammonium hydroxide (TMAH) in a pyrolysis unit coupled to gas chromatography–mass spectrometry (GC/MS). The isolated monomer mixture was used to study the sorption of three pesticides (isoproturon, methomyl and oxamyl). The modes of pesticide–sorbent interactions were analyzed by means of two modeling calculations, the first one representing only the mixture of suberin monomers used in the sorption study, and the second one including glycerol to the mixture of suberin monomers, as a building block of the suberin molecule. The results indicated that the highest sorption capacity exhibited by the sorbent was for isoproturon (33%) being methomyl and oxamyl sorbed by the main suberin components to a lesser extent (3% and < 1%, respectively). In addition to van der Waals interactions with the apolar region of sorbent and isoproturon, modeling calculations evidenced the formation of a hydrogen bond between the isoproturon NH group and a carboxylic oxygen atom of a suberin monomer. In the case of methomyl and oxamyl only weak van der Waals interactions stabilize the pesticide–sorbent adducts. The presence of glycerol in the model provoked significant changes in the interactions with isoproturon and methomyl. - Highlights: • Suberin has low affinity to retain pesticides of aliphatic character. • Suberin has a moderate affinity to adsorb isoproturon. • Modeling calculations show that apolar portion of suberin interacts with isoproturon.

  3. Synthesis, micellization behavior, antimicrobial and intercalative DNA binding of some novel surfactant copper(II) complexes containing modified phenanthroline ligands.

    Science.gov (United States)

    Nagaraj, Karuppiah; Ambika, Subramanian; Rajasri, Shanmugasundaram; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2014-10-01

    The novel surfactant copper(II) complexes, [Cu(ip)2DA](ClO4)21, [Cu(dpqc)2DA](ClO4)22, [Cu(dppn)2DA](ClO4)23, where ip=imidazo[4,5-f][1,10]phenanthroline, dpqc=dipyrido[3,2-a:2',4'-c](6,7,8,9-tetrahydro)phenazine, dppn=benzo[1]dipyrido[3,2-a':2',3'-c]phenazine and DA-dodecylamine, were synthesized and characterized by physico-chemical and spectroscopic methods. In these complexes 1-3, the geometry of copper metal ions was described as square pyramidal. The critical micelle concentration (CMC) value of these surfactant copper(II) complexes in aqueous solution was found out from conductance measurements. Specific conductivity data at different temperatures served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔGm°, ΔHm° and ΔSm°). The binding interaction of these complexes with DNA (calf thymus DNA) in Tris buffer was studied by physico-chemical techniques. In the presence of the DNA UV-vis spectrum of complexes showed red shift of the absorption band along with significant hypochromicity indicating intercalation of our complexes with nucleic acids. Competitive binding study with ethidium bromide (EB) shows that the complexes exhibit the ability to displace the nucleic acid-bound EB indicating that the complexes bind to nucleic acids in strong competition with EB for the intercalative binding site. Observed changes in the circular dichoric spectra of DNA in the presence of surfactant complexes support the strong binding of complexes with DNA. CV results also confirm this mode of binding. Some significant thermodynamic parameters of the binding of the titled complexes to DNA have also been determined. The results reveal that the extent of DNA binding of 3 was greater than that of 1 and 2. The antibacterial and antifungal screening tests of these complexes have shown good results compared to its precursor chloride complexes. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Synthesis, structure characterization, DNA binding, and cleavage properties of mononuclear and tetranuclear cluster of copper(II) complexes.

    Science.gov (United States)

    Vafazadeh, Rasoul; Hasanzade, Naime; Heidari, Mohammad Mehdi; Willis, Anthony C

    2015-01-01

    Two copper(II) complexes, cluster 1, and mononuclear 2, have been synthesized by reacting acetylacetone and benzohydrazide (1:1 ratio for 1 and 1:2 ratio for 2) with CuCl(2) in a methanol solution. In 2, which is a new complex, the ligand acts as a tetradentate which binds the metal ion via two amide-O atoms and two imine-N atoms providing an N(2)O(2) square-planar around the copper(II) ion. The absorption spectra data evidence strongly suggested that the two copper(II) compounds could interact with CT-DNA (intrinsic binding constant, K(b) = 0.45×10(4) M-1 for 1 and K(b) = 2.39×10(4) M-1 for 2). The super coiled plasmid pBR322 DNA cleavage ability was studied with 1 and 2 in the presence and absence of H(2)O(2) as an oxidant. In both the absence and the presence of an oxidizing agent, complex 2 exhibited no nuclease activity. However, even in the absence of an oxidant, complex 1 exhibited significant DNA cleavage activity.

  5. Characterization of the P. Brevis Polyether Neurotoxin Binding Component in Excitable Membranes

    Science.gov (United States)

    1991-09-14

    Prorocentrum lima . In the case of the brevetoxins, each of the major toxins is anticipated in routine yield, saxitoxin and at least 5 derivatives were to be...388 11. TITLE (Include Security Classification) (U) Characterization of the P. brevis Polyether Neuro- toxin Binding Component in Excitable Membranes 12...FIELD GROUP SUB-GROUP Iarine toxins , sodium channel, photoaffinity probe 06 20 ffinity column, receptor binding, brevetoxin, 06 15 saxitoxin

  6. Demonstration of binding components specific for 7,8-disubstituted guanine ribonucleosides in murine B lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, M.G. (Research Institute of Scripps Clinic, La Jolla, CA (USA))

    1990-12-25

    7,8-Disubstituted guanine ribonucleosides are known to be potent intracellular modulators of immune responses. These compounds trigger and modulate a wide variety of lymphocyte responses including effects exerted directly on B cells. However, little is known about their mechanism of action. The current paper describes studies undertaken to evaluate whether binding components specific for these bioactive molecules exist in splenic B lymphocytes. After exposure of cells to labeled nucleoside, two different pools of nucleoside can be distinguished: a rapidly exchangeable nucleoside pool and a slowly exchangeable pool. The material in the latter pool consists of authentic unaltered nucleoside that is complexed to a relatively hydrophobic cellular component with an apparent Mr of 30,000-40,000; binding appears to interfere with free interaction of the nucleoside's cis hydroxyls with a boronate affinity resin. The slowly exchangeable nucleoside pool is seen to localize predominantly to the nucleus in electron microscopic autoradiographs. This pool is maximally bound by 30 min of incubation. Specific, saturable binding is demonstrable, with an apparent Kd of approximately 7 microM. This value correlates well with concentrations at which half-maximal biological activity occurs and suggests that the binding component likely mediates antigen-dependent immunomodulatory activity. Splenic B cells express approximately 2 x 10(4) binding sites/cell, whereas thymic lymphocytes, which do not respond functionally to nucleosides, do not display a measurable number of nucleoside binding sites. Ligand specificity of the binding interaction is confirmed by binding inhibition studies, in which binding inhibitory activity of unlabeled agonistic structural analogs recapitulate their degree of immunobiological activity.

  7. Halide Binding and Inhibition of Laccase Copper Clusters: The Role of Reorganization Energy

    DEFF Research Database (Denmark)

    Kepp, Kasper Planeta

    2015-01-01

    complicate characterization. Understanding these processes at the molecular level is thus desirable but theoretically unexplored. This paper reports systematic calculations of geometries, reorganization energies, and ionization energies for all partly oxidized states of the trinuclear copper clusters...

  8. Magnesium, zinc and copper in plasma and blood cellular components in children with IDDM.

    Science.gov (United States)

    Rohn, R D; Pleban, P; Jenkins, L L

    1993-04-16

    The levels of magnesium (Mg), zinc (Zn) and copper (Cu) in the plasma, erythrocytes (RBC) and polymorphonuclear (PMN) and lymphocyte (L), leukocytes (WBC) of 45 diabetic children were compared to those of 12 normal children and were related to the diabetic control via HbA1 and fasting blood sugar (FBS) assessments. Mineral levels were determined via Zeeman-effect atomic absorption spectrophotometry following separation of plasma, RBC, and WBC fractions (PMN vs. M). ANOVA (four-way, blood components, by two-way, diabetic vs. normal children) was significant for Mg only (F = 4.60, P < 0.004). Plasma Mg and M-WBC Mg were significantly lower in children with diabetes (780 +/- 16 vs. 860 +/- 29 mumol/l and 519 +/- 33 vs. 866 +/- 86 micrograms/10(10) cells, respectively). RBC Zn was significantly lower in diabetic youngsters by t-test (0.48 +/- 0.012 vs. 0.57 +/- 0.046 per mumol/g Hgb, t = 2.79, P < 0.004), but the ANOVA for Zn was not significant. Cu level differences were not significant. HbA1 was predicted only by PMN-WBC Mg (F = 8.78, P < 0.04) and FBS by none. In conclusion, the mineral status of these diabetic children was altered in regard to Mg, but was mainly independent of diabetic control.

  9. Environmental health hazards of e-cigarettes and their components: Oxidants and copper in e-cigarette aerosols

    International Nuclear Information System (INIS)

    Lerner, Chad A.; Sundar, Isaac K.; Watson, Richard M.; Elder, Alison; Jones, Ryan; Done, Douglas; Kurtzman, Rachel; Ossip, Deborah J.; Robinson, Risa; McIntosh, Scott; Rahman, Irfan

    2015-01-01

    To narrow the gap in our understanding of potential oxidative properties associated with Electronic Nicotine Delivery Systems (ENDS) i.e. e-cigarettes, we employed semi-quantitative methods to detect oxidant reactivity in disposable components of ENDS/e-cigarettes (batteries and cartomizers) using a fluorescein indicator. These components exhibit oxidants/reactive oxygen species reactivity similar to used conventional cigarette filters. Oxidants/reactive oxygen species reactivity in e-cigarette aerosols was also similar to oxidant reactivity in cigarette smoke. A cascade particle impactor allowed sieving of a range of particle size distributions between 0.450 and 2.02 μm in aerosols from an e-cigarette. Copper, being among these particles, is 6.1 times higher per puff than reported previously for conventional cigarette smoke. The detection of a potentially cytotoxic metal as well as oxidants from e-cigarette and its components raises concern regarding the safety of e-cigarettes use and the disposal of e-cigarette waste products into the environment. - Highlights: • E-cigarettes disposal is associated with environmental health hazard/pollution. • Oxidants associated with electronic cigarette components and aerosols. • Metal copper and nanoparticles detected in electronic cigarette aerosols. • Environmental disposal of e-cigarettes components must be regulated with guidelines. - An electronic cigarette with disposable cartomizer exhibits oxidant reactivity similar to conventional cigarettes and releases copper and other particles associated with its aerosols

  10. Evaluation of copper alloys for fusion reactor divertor and first wall components

    DEFF Research Database (Denmark)

    Fabritsiev, S.A.; Zinkle, S.J.; Singh, B.N.

    1996-01-01

    , creep, and low-temperature radiation embrittlement. Low-temperature radiation embrittlement at T-irr precipitation-hardened (PH) copper alloys, as their uniform elongation at T-test - T-irr - 100 degrees C drops...... to similar to 0.1% after irradiation doses of 0.01 to 0.1 dpa. At irradiation temperatures above 300 degrees C, pronounced softening occurs in PH copper alloys due to radiation-enhanced precipitate coarsening and dislocation recovery and recrystallization processes. The DS copper alloys are relatively......This paper presents a critical analysis of the main factors of radiation damage limiting the possibility to use copper alloys in the ITER divertor and first wall structure. In copper alloys the most significant types of radiation damage in the proposed temperature-dose operation range are swelling...

  11. Evaluation of copper alloys for fusion reactor divertor and first wall components

    DEFF Research Database (Denmark)

    Fabritsiev, S.A.; Zinkle, S.J.; Singh, B.N.

    1996-01-01

    This paper presents a critical analysis of the main factors of radiation damage limiting the possibility to use copper alloys in the ITER divertor and first wall structure. In copper alloys the most significant types of radiation damage in the proposed temperature-dose operation range are swellin...... strengthened copper (Cu-Al2O3) is considered to be the best candidate for high heat flux structural applications, followed by CuNiBe and CuCrZr.......This paper presents a critical analysis of the main factors of radiation damage limiting the possibility to use copper alloys in the ITER divertor and first wall structure. In copper alloys the most significant types of radiation damage in the proposed temperature-dose operation range are swelling......, creep, and low-temperature radiation embrittlement. Low-temperature radiation embrittlement at T-irr alloys, as their uniform elongation at T-test - T-irr - 100 degrees C drops...

  12. Experimental and molecular modeling studies on the DNA-binding of diazacyclam-based acrocyclic copper complex.

    Science.gov (United States)

    Shahabadi, Nahid; Hakimi, Mohammad; Morovati, Teimoor; Falsafi, Monireh; Fili, Soraya Moradi

    2017-02-01

    The interaction of a new macrocyclic copper complex, [CuL(NO 3 ) 2 ] in which L is 1,3,6,10,12,15-hexaaza tricyclo[13.3.1.1 6,10 ] eicosane was investigated in vitro under simulated physiological conditions by multi-spectroscopic techniques and molecular modeling study. The fluorescence spectroscopy and UV absorption spectroscopy indicated the complex interacted with ct-DNA in a groove binding mode while the binding constant of UV-vis and the number of binding sites were 1.0±0.2×10 4 Lmol -1 and 1.01, respectively. The fluorometric studies showed that the reaction between the complex with ct-DNA is exothermic (ΔH=14.85kJmol -1 ; ΔS=109.54Jmol -1 K -1 ). Circular dichroism spectroscopy (CD) was employed to measure the conformational change of DNA in the presence of [CuL(NO 3 ) 2 ] complex. Furthermore, the complex induces detectable changes in the viscosity of DNA. The molecular modeling results illustrated that the complex strongly binds to groove of DNA. Experimental and molecular modeling results showed that Cu(II) complex bound to DNA by a groove binding mode. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Specific cell components of Bacteroides gingivalis mediate binding and degradation of human fibrinogen

    Energy Technology Data Exchange (ETDEWEB)

    Lantz, M.S.; Allen, R.D.; Vail, T.A.; Switalski, L.M.; Hook, M. (Univ. of Alabama at Birmingham (USA))

    1991-01-01

    Bacteroides (Porphyromonas) gingivalis, which has been implicated as an etiologic agent in human periodontal diseases, has been shown to bind and degrade human fibrinogen. B. gingivalis strains bind fibrinogen reversibly and with high affinity and bind to a specific region of the fibrinogen molecule that appears to be located between the D and E domains. The authors now report that human fibrinogen is bound and then degraded by specific B. gingivalis components that appear to be localized at the cell surface. Fibrinogen binding to bacterial cells occurred at 4, 22, and 37{degree}C. A functional fibrinogen-binding component (M{sub r}, 150 000) was identified when sodium dodecyl sulfate-solubilized bacteria were fractionated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transferred to nitrocellulose membranes, and probed with {sup 125}I-fibrinogen. Fibrinogen degradation did not occur at 4{degree}C but did occur at 22 and 37{degree}C. When bacteria and iodinated fibrinogen were incubated at 37{degree}C, two major fibrinogen fragments (M{sub r}, 97 000 and 50 000) accumulated in incubation mixture supernatant fractions. Two major fibrinogen-degrading components (M{sub r}, 120 000 and 150 000) have been identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in substrate-containing gels. Fibrinogen degradation by the M{sub r}-120 000 and -150 000 proteases was enhanced by reducing agents, completely inhibited by N-{alpha}-p-tosyl-L-lysyl chloromethyl ketone, and partially inhibited by n-ethyl maleimide, suggesting that these enzymes are thiol-dependent proteases with trypsinlike substrate specificity. The fibrinogen-binding component could be separated from the fibrinogen-degrading components by selective solubilization of bacteria in sodium deoxycholate.

  14. Identification of spectrin as a calmodulin-binding component in the pituitary gonadotrope

    International Nuclear Information System (INIS)

    Wooge, C.H.

    1989-01-01

    Gonadotropin releasing hormone (GnRH) is a hypothalamic decapeptide which stimulates the release of luteinizing hormone (LH) and follicle stimulating hormone (FSH) from the pituitary. Ca 2+ fulfills the requirements of a second messenger for this system. Inhibition of calmodulin will inhibit GnRH stimulated LH release. The aim of the present studies has been to identify the locus of action of calmodulin within the pituitary. By use of an 125 I-calmodulin gel overlayer assay, five major Ca 2+ -dependent 125 I-calmodulin labelled components of subunit M r > 205,000; 200,000; 135,000; 60,000; and 52,000 have been identified. This labeling was found to be phenothiazine-sensitive. Ca 2+ -independent binding that was observed appears to be due to hydrophobic interactions of calmodulin with acid-soluble proteins, principally histones. Subcellular fractionation revealed that the Ca 2+ -dependent calmodulin-binding components are localized primarily in the cytosolic fraction. Separation of dispersed anterior pituitary cells through a linear Metrizamide gradient yielded gonadotrope-enriched fractions, which were found to contain all five 125 I-calmodulin binding components corresponding to the major bands in the pituitary homogenate. The calmodulin-binding component levels do not appear to be differentially regulated by steroids. The calmodulin binding component with a M r > 205,000 has been identified as spectrin. Spectrin-like immunoreactivity and 125 I-calmodulin-binding activity in pituitary tissue homogenates co-migrated in various percentage acrylamide gels with avian erythrocyte spectrin. Spectrin was detected in a gonadotrope-enriched fraction by immunoblotting, and confirmed in gonadotropes by indirect immunofluorescence of cultured pituitary cells in which spectrin- and LH-immunoreactivity co-localized

  15. Characterization of the Organic Component of Low-Molecular-Weight Chromium-Binding Substance and Its Binding of Chromium123

    Science.gov (United States)

    Chen, Yuan; Watson, Heather M.; Gao, Junjie; Sinha, Sarmistha Halder; Cassady, Carolyn J.; Vincent, John B.

    2011-01-01

    Chromium was proposed to be an essential element over 50 y ago and was shown to have therapeutic potential in treating the symptoms of type 2 diabetes; however, its mechanism of action at a molecular level is unknown. One chromium-binding biomolecule, low-molecular weight chromium-binding substance (LMWCr or chromodulin), has been found to be biologically active in in vitro assays and proposed as a potential candidate for the in vivo biologically active form of chromium. Characterization of the organic component of LMWCr has proven difficult. Treating bovine LMWCr with trifluoroacetic acid followed by purification on a graphite powder micro-column generates a heptapeptide fragment of LMWCr. The peptide sequence of the fragment was analyzed by MS and tandem MS (MS/MS and MS/MS/MS) using collision-induced dissociation and post-source decay. Two candidate sequences, pEEEEGDD and pEEEGEDD (where pE is pyroglutamate), were identified from the MS/MS experiments; additional tandem MS suggests the sequence is pEEEEGDD. The N-terminal glutamate residues explain the inability to sequence LMWCr by the Edman method. Langmuir isotherms and Hill plots were used to analyze the binding constants of chromic ions to synthetic peptides similar in composition to apoLMWCr. The sequence pEEEEGDD was found to bind 4 chromic ions per peptide with nearly identical cooperativity and binding constants to those of apoLMWCr. This work should lead to further studies elucidating or eliminating a potential role for LMWCr in treating the symptoms of type 2 diabetes and other conditions resulting from improper carbohydrate and lipid metabolism. PMID:21593351

  16. Insights into the oxidative degradation of cellulose by a copper metalloenzyme that exploits biomass components.

    Science.gov (United States)

    Quinlan, R Jason; Sweeney, Matt D; Lo Leggio, Leila; Otten, Harm; Poulsen, Jens-Christian N; Johansen, Katja Salomon; Krogh, Kristian B R M; Jørgensen, Christian Isak; Tovborg, Morten; Anthonsen, Annika; Tryfona, Theodora; Walter, Clive P; Dupree, Paul; Xu, Feng; Davies, Gideon J; Walton, Paul H

    2011-09-13

    The enzymatic degradation of recalcitrant plant biomass is one of the key industrial challenges of the 21st century. Accordingly, there is a continuing drive to discover new routes to promote polysaccharide degradation. Perhaps the most promising approach involves the application of "cellulase-enhancing factors," such as those from the glycoside hydrolase (CAZy) GH61 family. Here we show that GH61 enzymes are a unique family of copper-dependent oxidases. We demonstrate that copper is needed for GH61 maximal activity and that the formation of cellodextrin and oxidized cellodextrin products by GH61 is enhanced in the presence of small molecule redox-active cofactors such as ascorbate and gallate. By using electron paramagnetic resonance spectroscopy and single-crystal X-ray diffraction, the active site of GH61 is revealed to contain a type II copper and, uniquely, a methylated histidine in the copper's coordination sphere, thus providing an innovative paradigm in bioinorganic enzymatic catalysis.

  17. In vitro DNA binding studies of the sweetening agent saccharin and its copper(II) and zinc(II) complexes.

    Science.gov (United States)

    Icsel, Ceyda; Yilmaz, Veysel T

    2014-01-05

    The interactions of fish sperm DNA (FS-DNA) with the sodium salt of sweetener saccharin (sacH) and its copper and zinc complexes, namely [M(sac)2(H2O)4]·2H2O (M=Cu(II) or Zn(II)) were studied by using UV-Vis titration, fluorometric competition, thermal denaturation, viscosity and gel electrophoresis measurements. The intrinsic binding constants (Kb) obtained from absorption titrations were estimated to be 2.86 (±0.06)×10(4)M(-1) for Na(sac), 6.67 (±0.12)×10(4)M(-1) for Cu-sac and 4.01 (±0.08)×10(4)M(-1) for Zn-sac. The Cu-sac complex binds to FS-DNA via intercalation with a KA value of 50.12 (±0.22)×10(4)M(-1) as evidenced by competitive binding studies with ethidium bromide. Moreover, competition experiments with Hoechst 33258 are indicative of a groove binding mode of Na(sac) and Zn-sac with binding constants of 3.13 (±0.16)×10(4)M(-1) and 5.25 (±0.22)×10(4)M(-1), respectively. The spectroscopic measurements indicate a moderate DNA binding affinity of Na(sac) and its metal complexes. The suggested binding modes are further confirmed by the thermal denaturation and viscosity measurements. In addition, Cu-sac and Zn-sac show weak ability to damage to pBR322 supercoiled plasmid DNA. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. [Copper level and metallothionein-like Cu-binding protein in cultured skin fibroblasts from patients with Menkes' disease and Wilson's disease].

    Science.gov (United States)

    Sato, M; Hayashi, A; Ito, H; Tojo, M; Arima, M

    1984-11-01

    Copper concentration, intracellular copper distribution, and inducibility of metallothionein-like metal-binding protein (MLP) by copper or cadmium addition to culture medium were compared among three types of skin fibroblasts derived from patients with Menkes' disease and Wilson's disease, both exhibiting genetic defects of copper metabolism, and from normal subjects (control). Skin fibroblasts were cultivated in Dulbecco's modified Eagle's medium supplemented with 10% fetal calf serum and antibiotics in 5% CO2 at 37 degrees C. Cells were harvested with rubber-policeman, washed twice with phosphate-buffered saline, pH 7.2, suspended in deionized water, and homogenized. The homogenate from each cell type was used to determine the concentration of copper by atomic absorption spectrophotometry employing graphite-rod atomizer after lyophilization, ashing in HNO3, and coprecipitation with zirconium. Intracellular copper concentration was elevated in Menkes' cells (420 ng Cu/mg of protein) and Wilson's cells (217 ng Cu/mg of protein) than in control cells (90.0 ng Cu/mg of protein), although one of four Wilson's strains showed normal copper level (70.5 ng Cu/mg of protein). Cytosol copper concentration was 5.8-fold higher in Menkes' cells but only 1.3-fold in Wilson's cells than in control cells, and cytosol copper accounted for only 35% of total intracellular copper in Wilson's cells as compared with 68% and 52% in Menkes' and control cells, respectively. These suggest that accumulated copper in each cell type is differently distributed within cells; in Menkes' cells exclusively into cytosol, but in Wilson's cells into particulates rather than cytosol. Elution profiles from Sephadex G-75 columns indicated that most of copper had bound to MLP in Menkes' cells, though no Cu-MLP was detectable in Wilson's or control cells under these experimental conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

  19. Copper(II) complexes with 4-hydroxyacetophenone-derived acylhydrazones: Synthesis, characterization, DNA binding and cleavage properties

    Science.gov (United States)

    Gup, Ramazan; Gökçe, Cansu; Aktürk, Selçuk

    2015-01-01

    Two new Cu(II) complexes of Schiff base-hydrazone ligands, hydroxy-N‧-[(1Z)-1-(4-hydroxyphenyl)ethylidene]benzohydrazide [H3L1] and ethyl 2-(4-(1-(2-(4-(2-ethoxy-2-oxoethoxy)benzoyl)hydrazono)ethyl)phenoxy)acetate (HL2) have been synthesized and then characterized by microcopy and spectral studies. X-ray powder diffraction illustrates that [Cu(L2)2] complex is crystalline in nature whereas [Cu(H2L1)2]·2H2O has an amorphous structure. Binding of the copper complexes with Calf thymus DNA (CT-DNA) has been investigated by UV-visible spectra, exhibiting non-covalent binding to CT-DNA. DNA cleavage experiments have been also investigated by agarose gel electrophoresis in the presence and absence of an oxidative agent (H2O2). The effect of complex concentration on the DNA cleavage reaction has been also studied. Both copper complexes show nuclease activity, which significantly depends on concentrations of the complexes, in the presence of H2O2 through oxidative mechanism whereas they slightly cleavage DNA in the absence an oxidative agent.

  20. Synthesis and thermal studies of tetraaza macrocylic ligand and its transition metal complexes. DNA binding affinity of copper complex.

    Science.gov (United States)

    Saif, M; Mashaly, Mahmoud M; Eid, Mohamed F; Fouad, R

    2011-09-01

    A Tetraaza Macrocylic Ligand (H2L) and its complexes, [Cd(H2L)(OH2)2](NO3)(2)·1/2OH2 (I), [Co(H2L)(OH2)](NO3)(2)·1/2OH2 (II), [Cu(H2L)(NO3)2]·3/2OH2 (III) and [Ni(H2L)(NO3)(OH2)]NO3·OH2 (IV), have been synthesized and characterized on the basis of elemental analysis, molar conductivity, 1H NMR, UV-vis, FT-IR and mass spectroscopy. All results confirm that the prepared compounds have 1:1 metal-to-ligand stoichiometry, octahedral configuration and the ligand behaves as a neutral tetradendate towards the metal ions. [CdL(OH2)2] (V), [CoL(OH2)2] (VI), [CuL(OH2)2] (VII) and [Ni(H2L)(NO3)2] (VIII) were synthesized pyrolytically in solid state from corresponding compounds (I-IV). Analytical results of complexes (V-VIII) show that the ligand behaves either as a neutral tetradendate or dianionic tetradentate ligand towards the metal ions. The binding of H2L and its copper complex (III) to DNA has been investigated by ultraviolet absorption spectroscopy. The experiments indicate that H2L and its copper complex (III) can bind to DNA through an intercalative mode. The H2L and its copper complex (III) exhibited anti-tumor activity against Ehrlich Acites Carcinoma (E.A.C) at the concentration of 100 μg/ml. Copyright © 2011 Elsevier B.V. All rights reserved.

  1. Comparing Independent Component Analysis with Principle Component Analysis in Detecting Alterations of Porphyry Copper Deposit (case Study: Ardestan Area, Central Iran)

    Science.gov (United States)

    Mahmoudishadi, S.; Malian, A.; Hosseinali, F.

    2017-09-01

    The image processing techniques in transform domain are employed as analysis tools for enhancing the detection of mineral deposits. The process of decomposing the image into important components increases the probability of mineral extraction. In this study, the performance of Principal Component Analysis (PCA) and Independent Component Analysis (ICA) has been evaluated for the visible and near-infrared (VNIR) and Shortwave infrared (SWIR) subsystems of ASTER data. Ardestan is located in part of Central Iranian Volcanic Belt that hosts many well-known porphyry copper deposits. This research investigated the propylitic and argillic alteration zones and outer mineralogy zone in part of Ardestan region. The two mentioned approaches were applied to discriminate alteration zones from igneous bedrock using the major absorption of indicator minerals from alteration and mineralogy zones in spectral rang of ASTER bands. Specialized PC components (PC2, PC3 and PC6) were used to identify pyrite and argillic and propylitic zones that distinguish from igneous bedrock in RGB color composite image. Due to the eigenvalues, the components 2, 3 and 6 account for 4.26% ,0.9% and 0.09% of the total variance of the data for Ardestan scene, respectively. For the purpose of discriminating the alteration and mineralogy zones of porphyry copper deposit from bedrocks, those mentioned percentages of data in ICA independent components of IC2, IC3 and IC6 are more accurately separated than noisy bands of PCA. The results of ICA method conform to location of lithological units of Ardestan region, as well.

  2. COMPARING INDEPENDENT COMPONENT ANALYSIS WITH PRINCIPLE COMPONENT ANALYSIS IN DETECTING ALTERATIONS OF PORPHYRY COPPER DEPOSIT (CASE STUDY: ARDESTAN AREA, CENTRAL IRAN

    Directory of Open Access Journals (Sweden)

    S. Mahmoudishadi

    2017-09-01

    Full Text Available The image processing techniques in transform domain are employed as analysis tools for enhancing the detection of mineral deposits. The process of decomposing the image into important components increases the probability of mineral extraction. In this study, the performance of Principal Component Analysis (PCA and Independent Component Analysis (ICA has been evaluated for the visible and near-infrared (VNIR and Shortwave infrared (SWIR subsystems of ASTER data. Ardestan is located in part of Central Iranian Volcanic Belt that hosts many well-known porphyry copper deposits. This research investigated the propylitic and argillic alteration zones and outer mineralogy zone in part of Ardestan region. The two mentioned approaches were applied to discriminate alteration zones from igneous bedrock using the major absorption of indicator minerals from alteration and mineralogy zones in spectral rang of ASTER bands. Specialized PC components (PC2, PC3 and PC6 were used to identify pyrite and argillic and propylitic zones that distinguish from igneous bedrock in RGB color composite image. Due to the eigenvalues, the components 2, 3 and 6 account for 4.26% ,0.9% and 0.09% of the total variance of the data for Ardestan scene, respectively. For the purpose of discriminating the alteration and mineralogy zones of porphyry copper deposit from bedrocks, those mentioned percentages of data in ICA independent components of IC2, IC3 and IC6 are more accurately separated than noisy bands of PCA. The results of ICA method conform to location of lithological units of Ardestan region, as well.

  3. Structural characterization of copper(II) binding to α-synuclein: Insights into the bioinorganic chemistry of Parkinson's disease

    Science.gov (United States)

    Rasia, Rodolfo M.; Bertoncini, Carlos W.; Marsh, Derek; Hoyer, Wolfgang; Cherny, Dmitry; Zweckstetter, Markus; Griesinger, Christian; Jovin, Thomas M.; Fernández, Claudio O.

    2005-01-01

    The aggregation of α-synuclein (AS) is characteristic of Parkinson's disease and other neurodegenerative synucleinopathies. We demonstrate here that Cu(II) ions are effective in accelerating AS aggregation at physiologically relevant concentrations without altering the resultant fibrillar structures. By using numerous spectroscopic techniques (absorption, CD, EPR, and NMR), we have located the primary binding for Cu(II) to a specific site in the N terminus, involving His-50 as the anchoring residue and other nitrogen/oxygen donor atoms in a square planar or distorted tetragonal geometry. The carboxylate-rich C terminus, originally thought to drive copper binding, is able to coordinate a second Cu(II) equivalent, albeit with a 300-fold reduced affinity. The NMR analysis of AS–Cu(II) complexes reveals the existence of conformational restrictions in the native state of the protein. The metallobiology of Cu(II) in Parkinson's disease is discussed by a comparative analysis with other Cu(II)-binding proteins involved in neurodegenerative disorders. PMID:15767574

  4. DNA binding and gel electrophoresis studies of a copper (II) complex containing mixed aliphatic and aromatic dinitrogen ligands.

    Science.gov (United States)

    Shahabadi, Nahid; Darabi, Farivash; Maghsudi, Maryam; Kashanian, Soheila

    2010-06-01

    The interaction of a novel mixed ligand copper (II) complex, [Cu(N-N)(L)(EtOH)](NO(3))(2) . 2H(2)O, in which N-N indicates 2,9-dimethyl-1,10-phenanthroline and L indicates N,N-dimethyltrimethylenediamine with calf thymus DNA was investigated by absorption, circular dichroism, voltammetric, and viscosimetric techniques. The absorption spectra of the complex with calf thymus DNA showed a marked hypochromism in the pi --> pi* and metal to ligand charge transfer (MLCT) transitions, with no obvious red shift attributed to a partial intercalation. The intrinsic binding constant (K(b)) was determined as 2 x 10(5) M(-1). There was slight to appreciable changes in the relative viscosity of DNA, which is consistent with enhanced hydrophobic interaction of the methyl-substituted phen ring and partial intercalation mode of binding. Electrochemical studies showed a decrease in the peak current, which is ascribed to the strong binding between Cu (II) complex and DNA. The fluorescence spectral characteristics showed that the Cu (II) complex is able to displace the methylene blue bound to DNA, but not as complete as intercalative molecules. It is remarkable that this mixed ligand complex, in contrast to [Cu(2,9-dmp)(2)](+) (2,9-dmp = 2,9-dimethyl-1,10-phenanthroline), which fails to cleave DNA, has ability to cleave the supercoiled plasmid DNA.

  5. Development of bonding techniques between tungsten and copper alloy for plasma facing components by HIP method. 1. Bonding between tungsten and oxygen free copper

    International Nuclear Information System (INIS)

    Saito, Shigeru; Fukaya, Kiyoshi; Ishiyama, Shintaro; Eto, Motokuni; Akiba, Masato

    1999-08-01

    In recent years, it has been considered that W (tungsten) is one of candidate materials for armor tiles of plasma facing components, like first wall or divertor, of fusion reactor. On the other hand, oxygen free high thermal conductivity (OFHC)-copper is proposed as heat sink materials behind the plasma facing materials because of its high thermal conductivity. However, plasma facing components are exposed to cyclic high heat load and heavily irradiated by 14 MeV neutron. Under these conditions, many unfavorable effects, for instance, thermal stresses of bonding interface, irradiation damage and He atom production by nuclear transmutation, will be decreased bonding strength between W and Cu alloys. Therefore, it is necessary to develop a reliable bonding techniques in order to make plasma facing components which can resist them. Then, we started the bonding technology development by hot isostatic press (HIP) method to bond W with Cu alloys. In this experiments, to optimize HIP bonding conditions, four point bending were performed for each bonded conditions at temperature from R.T. to 873 K and we could get the best HIP bonding conditions for W and OFHC-Cu as 1273 K x 2 hours x 147 MPa. To evaluate bonding strength of the specimen bonded at these conditions, tensile tests were also performed at same temperature range. The tensile strength was similar with OFHC-Cu which were treated at same conditions. (author)

  6. Synthesis, Cytotoxic Activity, and DNA Binding Properties of Copper (II) Complexes with Hesperetin, Naringenin, and Apigenin

    OpenAIRE

    Tan, Mingxiong; Zhu, Jinchan; Pan, Yingming; Chen, Zhenfeng; Liang, Hong; Liu, Huagang; Wang, Hengshan

    2009-01-01

    Complexes of copper (II) with hesperetin, naringenin, and apigenin of general composition [CuL2(H2O)2]⋅nH2O (1–3) have been synthesized and characterized by elemental analysis, UV-Vis, FT-IR, ESI-MS, and TG-DTG thermal analysis. The free ligands and the metal complexes have been tested in vitro against human cancer cell lines hepatocellular carcinoma (HepG-2), gastric carcinomas (SGC-7901), and cervical carcinoma (HeLa). Complexes 1 and 3 were found to exhibit growth inhibition of SGC-79...

  7. Copper(II) Binding Sites in N-Terminally Acetylated α-Synuclein: A Theoretical Rationalization.

    Science.gov (United States)

    Ramis, Rafael; Ortega-Castro, Joaquín; Vilanova, Bartolomé; Adrover, Miquel; Frau, Juan

    2017-08-03

    The interactions between N-terminally acetylated α-synuclein and Cu(II) at several binding sites have been studied with DFT calculations, specifically with the M06 hybrid functional and the ωB97X-D DFT-D functional. In previous experimental studies, Cu(II) was shown to bind several α-synuclein residues, including Met1-Asp2 and His50, forming square planar coordination complexes. Also, it was determined that a low-affinity binding site exists in the C-terminal domain, centered on Asp121. However, in the N-terminally acetylated protein, present in vivo, the Met1 site is blocked. In this work, we simplify the representation of the protein by modeling each experimentally found binding site as a complex between an N-terminally acetylated α-synuclein dipeptide (or several independent residues) and a Cu(II) cation, and compare the results with a number of additional, structurally analogous sites not experimentally found. This way of representing the binding sites, although extremely simple, allows us to reproduce experimental results and to provide a theoretical rationale to explain the preference of Cu(II) for certain sites, as well as explicit geometrical structures for the complexes formed. These results are important to understand the interactions between α-synuclein and Cu(II), one of the factors inducing structural changes in the protein and leading to aggregated forms of it which may play a role in neurodegeneration.

  8. Mixed-ligand copper(ii) Schiff base complexes: the role of the co-ligand in DNA binding, DNA cleavage, protein binding and cytotoxicity.

    Science.gov (United States)

    Lian, Wen-Jing; Wang, Xin-Tian; Xie, Cheng-Zhi; Tian, He; Song, Xue-Qing; Pan, He-Ting; Qiao, Xin; Xu, Jing-Yuan

    2016-05-31

    Four novel mononuclear Schiff base copper(ii) complexes, namely, [Cu(L)(OAc)]·H2O (), [Cu(HL)(C2O4)(EtOH)]·EtOH (), [Cu(L)(Bza)] () and [Cu(L)(Sal)] () (HL = 1-(((2-((2-hydroxypropyl)amino)ethyl)imino)methyl)naphthalene-2-ol), Bza = benzoic acid, Sal = salicylic acid), were synthesized and characterized by X-ray crystallography, elemental analysis and infrared spectroscopy. Single-crystal diffraction analysis revealed that all the complexes were mononuclear molecules, in which the Schiff base ligand exhibited different coordination modes and conformations. The N-HO and O-HO inter- and intramolecular hydrogen bonding interactions linked these molecules into multidimensional networks. Their interactions with calf thymus DNA (CT-DNA) were investigated by UV-visible and fluorescence spectrometry, as well as by viscosity measurements. The magnitude of the Kapp values of the four complexes was 10(5), indicating a moderate intercalative binding mode between the complexes and DNA. Electrophoresis results showed that all these complexes induced double strand breaks of pUC19 plasmid DNA in the presence of H2O2 through an oxidative pathway. In addition, the fluorescence spectrum of human serum albumin (HSA) with the complexes suggested that the quenching mechanism of HSA by the complexes was a static process. Moreover, the antiproliferative activity of the four complexes against HeLa (human cervical carcinoma) and HepG-2 (human liver hepatocellular carcinoma) cells evaluated by colorimetric cell proliferation assay and clonogenic assay revealed that all four complexes had improved cytotoxicity against cancer cells. Inspiringly, complex , with salicylic acid as the auxiliary ligand, displayed a stronger anticancer activity, suggesting that a synergistic effect of the Schiff base complex and the nonsteroidal anti-inflammatory drug may be involved in the cell killing process. The biological features of mixed-ligand copper(ii) Schiff base complexes and how acetic auxiliary

  9. Fatty acid and drug binding to a low-affinity component of human serum albumin, purified by affinity chromatography

    DEFF Research Database (Denmark)

    Vorum, H; Pedersen, A O; Honoré, B

    1992-01-01

    Binding equilibria for decanoate to a defatted, commercially available human serum albumin preparation were investigated by dialysis exchange rate determinations. The binding isotherm could not be fitted by the general binding equation. It was necessary to assume that the preparation was a mixture...... of two albumin components about 40% of the albumin having high affinity and about 60% having low affinity. By affinity chromatography we succeeded in purifying the low-affinity component from the mixture. The high-affinity component, however, could not be isolated. We further analyzed the fatty acid...... and drug binding abilities of the low-affinity component. The fatty acids decanoate, laurate, myristate and palmitate were bound with higher affinity to the mixture than to the low-affinity component. Diazepam was bound with nearly the same affinity to the low-affinity component as to the albumin mixture...

  10. Prevention of iron- and copper-mediated DNA damage by catecholamine and amino acid neurotransmitters, L-DOPA, and curcumin: metal binding as a general antioxidant mechanism.

    Science.gov (United States)

    García, Carla R; Angelé-Martínez, Carlos; Wilkes, Jenna A; Wang, Hsiao C; Battin, Erin E; Brumaghim, Julia L

    2012-06-07

    Concentrations of labile iron and copper are elevated in patients with neurological disorders, causing interest in metal-neurotransmitter interactions. Catecholamine (dopamine, epinephrine, and norepinephrine) and amino acid (glycine, glutamate, and 4-aminobutyrate) neurotransmitters are antioxidants also known to bind metal ions. To investigate the role of metal binding as an antioxidant mechanism for these neurotransmitters, L-dihydroxyphenylalanine (L-DOPA), and curcumin, their abilities to prevent iron- and copper-mediated DNA damage were quantified, cyclic voltammetry was used to determine the relationship between their redox potentials and DNA damage prevention, and UV-vis studies were conducted to determine iron and copper binding as well as iron oxidation rates. In contrast to amino acid neurotransmitters, catecholamine neurotransmitters, L-DOPA, and curcumin prevent significant iron-mediated DNA damage (IC(50) values of 3.2 to 18 μM) and are electrochemically active. However, glycine and glutamate are more effective at preventing copper-mediated DNA damage (IC(50) values of 35 and 12.9 μM, respectively) than L-DOPA, the only catecholamine to prevent this damage (IC(50) = 73 μM). This metal-mediated DNA damage prevention is directly related to the metal-binding behaviour of these compounds. When bound to iron or copper, the catecholamines, amino acids, and curcumin significantly shift iron oxidation potentials and stabilize Fe(3+) over Fe(2+) and Cu(2+) over Cu(+), a factor that may prevent metal redox cycling in vivo. These results highlight the disparate antioxidant activities of neurotransmitters, drugs, and supplements and highlight the importance of considering metal binding when identifying antioxidants to treat and prevent neurodegenerative disorders.

  11. Binding of leachable components of polymethyl methacrylate (PMMA) and peptide on modified SPR chip

    International Nuclear Information System (INIS)

    Szaloki, M; Hegedus, Cs; Vitalyos, G; Harfalvi, J

    2013-01-01

    Many types of polymers are often used in dentistry, which may cause allergic reaction, mainly methyl methacrylate allergy due to the leachable, degradable components of polymerized dental products. The aim of this study was to investigate the interaction between the leachable components of PMMA and peptides by Fourier-transform Surface Plasmon Resonance (FT SPR). In our previous work binding of oligopeptides (Ph.D.-7 and Ph.D.-12 Peptide Library Kit) was investigated to PMMA surface by phage display technique. It was found that oligopeptides bounded specifically to PMMA surface. The most common amino acids were leucine and proline inside the amino acids sequences of DNA of phages. The binding of haptens, as formaldehyde and methacrylic acid, to frequent amino acids was to investigate on the modified gold SPR chip. Self assembled monolayer (SAM) modified the surface of gold chip and ensured the specific binding between the haptens and amino acids. It was found that amino acids bounded to modified SPR gold and the haptens bounded to amino acids by creating multilayer on the chip surface. By the application of phage display and SPR modern bioanalytical methods the interaction between allergens and peptides can be investigated

  12. Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect

    Directory of Open Access Journals (Sweden)

    Rene M Boiteau

    2016-11-01

    Full Text Available Organic ligands form strong complexes with many trace elements in seawater. Various metals can compete for the same ligand chelation sites, and the final speciation of bound metals is determined by relative binding affinities, concentrations of binding sites, uncomplexed metal concentrations, and association/dissociation kinetics. Different ligands have a wide range of metal affinities and specificities. However, the chemical composition of these ligands in the marine environment remains poorly constrained, which has hindered progress in modeling marine metal speciation. In this study, we detected and characterized natural ligands that bind copper (Cu and nickel (Ni in the eastern South Pacific Ocean with liquid chromatography tandem inductively coupled plasma mass spectrometry (LC-ICPMS, and high resolution electrospray ionization mass spectrometry (ESIMS. Dissolved Cu, Ni, and ligand concentrations were highest near the coast. Chromatographically unresolved polar compounds dominated ligands isolated near the coast by solid phase extraction. Offshore, metal and ligand concentrations decreased, but several new ligands appeared. One major ligand was detected that bound both Cu2+ and Ni2+. Based on accurate mass and fragmentation measurements, this compound has a molecular formula of C20H21N4O8S2 + M+ (M = metal isotope and contains several azole-like metal binding groups. Additional lipophilic Ni complexes were also present only in oligotrophic waters, with masses of 649, 698, and 712 m/z (corresponding to the 58Ni metal complex. Molecular formulae of C32H54N3O6S2Ni+ and C33H56N3O6S2Ni+ were determined for two of these compounds. Addition of Cu and Ni to the samples also revealed the presence of additional compounds that can bind both Ni and Cu. Although these specific compounds represent a small fraction of the total dissolved Cu and Ni pool, they highlight the compositional diversity and spatial heterogeneity of marine Ni and Cu ligands, as

  13. Role of polarity fractions of effluent organic matter in binding and toxicity of silver and copper.

    Science.gov (United States)

    Yoo, Jisu; Shim, Taeyong; Hur, Jin; Jung, Jinho

    2016-11-05

    This study evaluates the effect of the physicochemical properties of effluent organic matter (EfOM) from industrial and sewage wastewater treatment plants (WWTPs) on the binding and toxicity of Ag and Cu. EfOM was isolated into hydrophobic, transphilic, and hydrophilic fractions depending on its polarity, and was characterized by elemental, specific ultraviolet absorbance, and fluorescence excitation-emission matrix analyses. Our results suggest that the EfOM consists of microbially derived non-humic substances that have lower aromaticity than the Suwannee River natural organic matter (SR-NOM). The Freundlich model was better at explaining the binding of Ag and Cu onto both SR-NOM and EfOM than the Langmuir model. In particular, the hydrophilic fractions of sewage EfOM showed higher binding capacities and affinities for Ag and Cu than the corresponding hydrophobic fractions, resulting in better reduction of the acute toxicity of Ag and Cu towards Daphnia magna. However, in the case of both SR-NOM and industrial EfOM, the hydrophobic fractions were more efficient at reducing metal toxicity. These findings suggest that the EfOM has different physicochemical properties compared with NOM and that the binding and toxicity of heavy metals are largely dependent on the polarity fractions of EfOM. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Phloem RNA-binding proteins as potential components of the long-distance RNA transport system.

    Directory of Open Access Journals (Sweden)

    VICENTE ePALLAS

    2013-05-01

    Full Text Available RNA-binding proteins (RBPs govern a myriad of different essential processes in eukaryotic cells. Recent evidence reveals that apart from playing critical roles in RNA metabolism and RNA transport, RBPs perform a key function in plant adaption to various environmental conditions. Long distance RNA transport occurs in land plants through the phloem, a conducting tissue that integrates the wide range of signalling pathways required to regulate plant development and response to stress processes. The macromolecules in the phloem pathway vary greatly and include defence proteins, transcription factors, chaperones acting in long distance trafficking, and RNAs (mRNAs, siRNAs and miRNAs. How these RNA molecules translocate through the phloem is not well understood, but recent evidence indicates the presence of translocatable RNA-binding proteins in the phloem, which act as potential components of long distance RNA transport system. This review updates our knowledge on the characteristics and functions of RBPs present in the phloem.

  15. Development of a methodology based on metal-catalyzed oxidation reactions and mass spectrometry to determine the metal binding sites in copper metalloproteins.

    Science.gov (United States)

    Lim, Jihyeon; Vachet, Richard W

    2003-03-01

    Efforts have been made to develop a method that uses metal-catalyzed oxidation (MCO) reactions and mass spectrometry (MS) to identify the binding site of copper in metalloproteins. This method uses MCO reactions to oxidize the amino acids in the metal-binding site and MS to identify the amino acids that have been oxidized. Several reaction conditions, including Cu(II)/ascorbate/O2, Cu(II)/O2/H2O2, and Cu(II)/ascorbate/O2/H2O2, have been tested at varying concentrations to find the optimum conditions for specific oxidation of only the amino acids bound to copper. For small peptides, such as angiotensin I (Agt I) and [Gln11]-amyloid-beta-protein fragment 1-16 (A beta(1-16)), the optimum conditions for specific modification involve the use of Cu(II)/ascorbate/O2. For a larger protein, azurin, the speed and specificity of the MCO reactions are enhanced by the presence of a relatively high concentration of ascorbate (100 mM) and a small concentration of H2O2 (1 mM). Optimized reaction conditions combined with MS/MS and MSn analysis on a quadrupole ion trap mass spectrometer allow the copper-binding sites to be specifically identified. For Agt I and A beta(1-16), the amino acids bound to copper can be identified without any false positives. For azurin, four of the five amino acids bound to copper are identified with one false positive. This false positive, however, corresponds to the oxidation of Met44, which is probably due to its susceptibility to oxidation and its proximity to the only residue not identified (i.e., Gly45). The results altogether suggest that MCO reactions and MS provide a very promising approach for identifying the amino acid residues bound to copper in metalloproteins.

  16. Synthesis and Structure of a Ternary Copper(II) Complex with Mixed Ligands of Diethylenetriamine and Picrate: DNA/Protein-Binding Property and In Vitro Anticancer Activity Studies.

    Science.gov (United States)

    Shi, Ya-Ning; Zheng, Kang; Zhu, Ling; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2015-05-01

    Based on the importance of the design and synthesis of transition metal complexes with noncovalent DNA/protein-binding abilities in the field of metallo pharmaceuticals, a new mononuclear ternary copper(II) complex with mixed ligands of diethylenetriamine (dien) and picrate anion (pic), identified as [Cu(dien)(pic)](pic), was synthesized and characterized by elemental analysis, molar conductivity measurement, infrared spectrum, electronic spectral studies, and single-crystal X-ray diffractometry. The structure analysis reveals that the copper(II) complex crystallizes in the monoclinic space group P21 /c, and the copper(II) ion has a distorted square pyramidal coordination geometry. A two-dimensional supramolecular structure is formed through hydrogen bonds. The DNA/bovine serum albumin (BSA)-binding properties of the complex are explored, indicating that the complex can interact with herring sperm DNA via intercalation mode and bind to BSA responsible for quenching of tryptophan fluorescence by static quenching mechanism. The in vitro anticancer activity shows that the copper(II) complex is active against the selected tumor cell lines. © 2015 Wiley Periodicals, Inc.

  17. Synthesis, CMC Determination, Antimicrobial Activity and Nucleic Acid Binding of A Surfactant Copper(II) Complex Containing Phenanthroline and Alanine Schiff-Base.

    Science.gov (United States)

    Nagaraj, Karuppiah; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2014-03-01

    A new water-soluble surfactant copper(II) complex [Cu(sal-ala)(phen)(DA)] (sal-ala = salicylalanine, phen = 1,10-phenanthroline, DA = dodecylamine), has been synthesized and characterized by physico-chemical and spectroscopic methods. The critical micelle concentration (CMC) values of this surfactant-copper(II) complex in aqueous solution were obtained from conductance measurements. Specific conductivity data (at 303, 308, 313. 318 and 323 K) served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG(0)m, ΔH(0)m and ΔS(0)m). The interaction of this complex with nucleic acids (DNA and RNA) has been explored by using electronic absorption spectral titration, competitive binding experiment, cyclic voltammetry, circular dichroism (CD) spectra, and viscosity measurements. Electronic absorption studies have revealed that the complex can bind to nucleic acids by the intercalative binding mode which has been verified by viscosity measurements. The DNA binding constants have also been calculated (Kb = 1.2 × 10(5) M(-1) for DNA and Kb = 1.6 × 10(5) M(-1) for RNA). Competitive binding study with ethidium bromide (EB) showed that the complex exhibits the ability to displace the DNA-bound-EB indicating that the complex binds to DNA in strong competition with EB for the intercalative binding site. The presence of hydrophobic ligands, alanine Schiff-base, phenanthroline and long aliphatic chain amine in the complex were responsible for this strong intercalative binding. The surfactant-copper (II) complex was screened for its antibacterial and antifungal activities against various microorganisms. The results were compared with the standard drugs, amikacin(antibacterial) and ketokonazole(antifungal).

  18. Binding of the bioactive component Aloe dihydroisocoumarin with human serum albumin

    Science.gov (United States)

    Zhang, Xiu-Feng; Xie, Ling; Liu, Yang; Xiang, Jun-Feng; Tang, Ya-Lin

    2008-11-01

    Aloe dihydroisocoumarin, one of new components isolated from Aloe vera, can scavenge reactive oxygen species. In order to explore the mechanism of drug action at a molecular level, the binding of Aloe dihydroisocoumarin with human serum albumin (HSA) has been investigated by using fluorescence, ultraviolet (UV), circular dichroism (CD) and Fourier transform infrared (FT-IR) spectroscopy, fluorescence dynamics, and molecular dynamic docking for the first time. We observed a quenching of fluorescence of HSA in the presence of Aloe dihydroisocoumarin and also analyzed the quenching results using the Stern-Volmer equation and obtained high affinity binding to HSA. An isoemissive point at 414 nm is seen, indicating that the quenching of HSA fluorescence depends on the formation of Aloe dihydroisocoumarin-HSA complex, which is further confirmed by fluorescence dynamic result. From the CD and FT-IR results, it is apparent that the interaction of Aloe dihydroisocoumarin with HSA causes a conformational change of the protein, with the gain of α-helix, β-sheet and random coil stability and the loss of β-turn content. Data obtained by fluorescence spectroscopy, fluorescence dynamics, CD, and FTIR experiments along with the docking studies suggest that Aloe dihydroisocoumarin binds to residues located in subdomain IIA of HSA.

  19. Activation of ADAM 12 protease by copper

    DEFF Research Database (Denmark)

    Loechel, F; Wewer, Ulla M.

    2001-01-01

    Conversion of latent proteases to the active form occurs by various mechanisms characteristic for different protease families. Here we report that the disintegrin metalloprotease ADAM 12-S is activated by Cu(II). Copper activation is distinct from the cysteine switch component of latency: elimina......Conversion of latent proteases to the active form occurs by various mechanisms characteristic for different protease families. Here we report that the disintegrin metalloprotease ADAM 12-S is activated by Cu(II). Copper activation is distinct from the cysteine switch component of latency......: elimination of the ADAM 12 cysteine switch by a point mutation in the propeptide had no effect on copper activation, whereas mutation of an unpaired cysteine residue in the catalytic domain resulted in a mutant form of ADAM 12-S that was insensitive to copper. This suggests a multi-step activation mechanism...... for ADAM 12 involving both furin cleavage and copper binding....

  20. Synthesis and DNA binding/cleavage of mononuclear copper(II) phenanthroline/bipyridine proline complexes.

    Science.gov (United States)

    Reddy, Pulimamidi R; Raju, Nomula; Manjula, Pallerla; Reddy, Karnati V G

    2007-07-01

    The complexes [Cu(II)(phen)(L-Pro)(H2O)]+ ClO4(-) (1; phen = 1,10-phenanthroline) and [Cu(II)(bipy)(L-Pro)(H2O)]+ ClO4(-) (2; bipy = 2,2'-bipyridine) were synthesized and characterized by IR, magnetic susceptibility, UV/VIS, EPR, ESI-MS, elemental analysis, and theoretical calculations. The metal center was found in a square-pyramidal geometry. UV/VIS, thermal-denaturation, and fluorescence-spectroscopic studies were conducted to assess the interaction of the complexes with CT-DNA. An intercalative mode of binding was found, with intrinsic binding constants (Kb) of 3.86x10(3) and 4.6x10(3) M(-1) and Stern-Volmer quenching constants (K) of 0.15 and 0.11 for 1 and 2, respectively. Interestingly, none of the Cu(II) complexes was able to cleave pUC-19 DNA, which is attributed to the absence of a Pro amide H-atom and inhibition of the formation of an OH radical from the axially coordinated H2O molecule.

  1. Changes in the binding of copper in the plasma of molybdenum supplemented rats

    Energy Technology Data Exchange (ETDEWEB)

    Nederbragt, H.; van den Hamer, C.J.

    1981-12-01

    After incubating plasma of Mo-supplemented rats (Mo-plasma) with /sup 64/Cu only part of it could be removed by dialysis against EDTA or histidine or by treatment with dithiocarbamate; this nondialyzable Cu was shown to be bound to albumin. The maximal amount of /sup 64/Cu bound this way equaled the Mo-induced increase in total plasma Cu. After addition of stable Cu, dialysis of Mo-plasma against a histidine solution showed that no extra Cu became tightly bound, suggesting that the /sup 64/Cu binding was due to an exchange between added /sup 64/Cu and stable Cu already present. Incubating Mo-plasma with Hg compounds prevented /sup 64/Cu binding and released stable Cu, indicating that Cu in Mo-plasma was sulfhydryl bound. Part of the Mo in Mo-plasma was freely dialyzable. The remaining part was shown to be SH bound as well. The estimated atomic ratio of SH-bound Cu and Mo was unity. Molybdenum increased the number of SH groups in plasma, and for each Cu atom at least one SH group was calculated to be present.

  2. Synthesis and characterization of mononuclear copper(II complex of tetradentate N2S2 donor set and the study of DNA and bovine serum albumin binding

    Directory of Open Access Journals (Sweden)

    Sandipan Sarkar

    2014-12-01

    Full Text Available One mononuclear copper(II complex, containing neutral tetradentate NSSN-type ligands, of formulation [Cu II(L 1Cl]ClO 4 (1, was synthesized and isolated in pure form [where L 1˭ 1,3-bis(3-pyridylmethylthiopropane]. Green-colored copper(II complex was characterized by physicochemical, spectroscopic methods and conductivity measurement. These experimental data matched well with the proposed structure of the complex. Biological activity of the complex (1 toward calf thymus DNA and bovine serum albumin has been examined systematically and groove-binding behavior of the Copper(II complex 1 with calf thymus DNA has been observed from the spectral study.

  3. Two novel copper complexes of 2,2'-bipyridine: evaluation of the DNA binding and cytotoxic activity.

    Science.gov (United States)

    Fei, Bao-Li; Li, Wen; Xu, Wu-Shuang; Li, Yang-Guang; Long, Jian-Ying; Liu, Qing-Bo; Shao, Kui-Zhan; Su, Zhong-Min; Sun, Wei-Yin

    2013-08-05

    Two novel copper-2,2'-bipyridine complexes [Cu(SAL)(2,2'-bipy)ClO4]2 (1) and [Cu(μ2-O)(2,2'-bipy)NO3]2 (2) (HSAL=salicylaldehyde) were synthesized and characterized by X-ray single-crystal diffraction, elemental analysis and IR spectra. The interactions of the complexes with salmon sperm DNA were investigated by viscosity analysis, UV, fluorescence and circular dichroism (CD) spectroscopic techniques. Absorption spectral (Kb=3.00×10(5)M(-1) (1), 3.49×10(5)M(-1)(2)), emission spectral ((Ksv) 3.33×10(4)M(-1) (1), 3.40×10(4)M(-1) (2)), and viscosity measurements reveal that 1 and 2 interact with DNA through intercalation. In fluorimetric studies, the enthalpy (ΔH>0) and entropy (ΔS>0) changes of the reactions between the Cu (II) complexes with DNA demonstrate hydrophobic interactions. In addition, CD study indicates the Cu (II) complexes cause a more B-like to a more A-like conformational change upon binding DNA. All the experimental results show that the interaction mode of the two complexes was greatly affected by the coordination environments of Cu (II) centers. Their in vitro cytotoxicity towards five selected tumor cell lines HepG-2, HeLa, NCI-H460, MCF-7 and HL-60 has been evaluated by MTT method, and 2 exhibits higher growth inhibition of the selected cell lines at concentration of 50 μM, this result is identical with their DNA binding ability order. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Synthesis, crystal structure and electrochemical and DNA binding studies of oxygen bridged-copper(II) carboxylate

    Science.gov (United States)

    Iqbal, Muhammad; Ali, Saqib; Tahir, Muhammad Nawaz; Muhammad, Niaz; Shah, Naseer Ali; Sohail, Manzar; Pandarinathan, Vedapriya

    2015-08-01

    A new binuclear O-bridged Cu(II) complex with 4-chlorophenyl acetate and 2,2‧-bipyridine has been synthesized and characterized using FT-IR, powder and single crystal XRD and electrochemical solution studies. The results revealed that the two penta-coordinated Cu(II) centers are linked by two carboxylate ligands in end-on bonding fashion. The coordination geometry is slightly distorted square pyramidal (SP) with bridging oxygen atoms occupying the apical position and other ligands lying in the equatorial plane. The striking difference in Cu-O bond distance of the bridging oxygen atom in the complex may be responsible for the SP geometry of Cu(II) ion. The complex gave rise to metal centered irreversible electro-activity where one electron Cu(II)/Cu(III) oxidation process and a single step two electron Cu(II)/Cu(0) reduction process was observed. The redox processes were found predominantly adsorption controlled. The values of diffusion coefficient and heterogeneous rate constant for oxidation process were 6.98 × 10-7 cm2 s-1 and 4.60 × 10-5 cm s-1 while the corresponding values for reduction were 5.30 × 10-8 cm2 s-1 and 5.41 × 10-6 cm s-1, respectively. The formal potential and charge transfer coefficient were also calculated. The DNA-binding ability was explored through cyclic voltammetry and UV-Visible spectroscopy. Diminution in the value of Do for oxidation indicated the binding of the complex with DNA corresponding to Kb = 8.58 × 104 M-1. UV-Visible spectroscopy yielded ε = 49 L mol-1 cm-1 and Kb = 2.96 × 104 M-1. The data of both techniques support each other. The self-induced redox activation of the complex, as indicated by cyclic voltammetry heralds its potential applications in redox catalysis and anticancer activity.

  5. Synthesis of mononuclear copper(II) complexes of acyclic Schiff's base ligands: Spectral, structural, electrochemical, antibacterial, DNA binding and cleavage activity

    Science.gov (United States)

    Jayamani, Arumugam; Thamilarasan, Vijayan; Sengottuvelan, Nallathambi; Manisankar, Paramasivam; Kang, Sung Kwon; Kim, Young-Inn; Ganesan, Vengatesan

    2014-03-01

    The mononuclear copper(II) complexes (1&2) of ligands L1 [N,N";-bis(2-hydroxy-5-methylbenzyl)-1,4-bis(3-iminopropyl)piperazine] or L2 [N,N";-bis(2-hydroxy-5-bromobenzyl)-1,4-bis(3-iminopropyl) piperazine] have been synthesized and characterised. The single crystal X-ray study had shown that ligands L1 and L2 crystallize in a monoclinic crystal system with P21/c space group. The mononuclear copper(II) complexes show one quasireversible cyclic voltammetric response near cathodic region (-0.77 to -0.85 V) in DMF assignable to the Cu(II)/Cu(I) couple. Binding interaction of the complexes with calf thymus DNA (CT DNA) investigated by absorption studies and fluorescence spectral studies show good binding affinity to CT DNA, which imply both the copper(II) complexes can strongly interact with DNA efficiently. The copper(II) complexes showed efficient oxidative cleavage of plasmid pBR322 DNA in the presence of 3-mercaptopropionic acid as reducing agent through a mechanistic pathway involving formation of singlet oxygen as the reactive species. The Schiff bases and their Cu(II) complexes have been screened for antibacterial activities which indicates that the complexes exhibited higher antimicrobial activity than the free ligands.

  6. The cooling of printed circuit board mounted components using copper ladder heat conduction to a cold wall

    Science.gov (United States)

    Dale, I. C.

    1982-09-01

    A series of experimental tests, designed to investigate the cooling of printed circuit board (PCB) mounted dual-in-line (DIL) components within an avionic box using the copper ladder/cold wall technique is described. Areas of investigation include avionic box orientation, side wall conduction, top plate finning, mixed air-wash, avionic power reduction, cooling air temperature reduction, cooling air mass flow rate reduction, cold wall heat pick-up and avionic box insulation. Results were obtained from thermocouple temperature measurements. The use of an aluminum alloy interplate to cool two adjacent PCBs is discussed. Results in graphic form are included together with a list of conclusions on the effects of all the major parameters considered.

  7. Recovery and recycling of aluminum, copper, and precious metals from dismantled weapon components

    International Nuclear Information System (INIS)

    Gundiler, I.H.; Lutz, J.D.; Wheelis, W.T.

    1994-01-01

    Sandia National Laboratories (SNL) is tasked to support The Department of Energy in the dismantlement and disposal of SNL designed weapon components. These components are sealed in a potting compound, and contain heavy metals, explosive, radioactive, and toxic materials. SNL developed a process to identify and remove the hazardous sub-components utilizing real-time radiography and abrasive water-jet cutting. The components were then crushed, granulated, screened, and separated into an aluminum and a precious-and-base-metals fraction using air-tables. Plastics were further cleaned for disposal as non-hazardous waste. New Mexico Bureau of Mines and Mineral Resources assisted SNL in investigation of size-reduction and separation technologies

  8. Corrigendum to "Synthesis, crystal structure and electrochemical and DNA binding studies of oxygen bridged-copper(II) carboxylate" [J. Mol. Struct. 1093 (2015) 135-143

    Science.gov (United States)

    Iqbal, Muhammad; Ali, Saqib; Tahir, Muhammad Nawaz; Muhammad, Niaz; Shah, Naseer Ali; Sohail, Manzar; Pandarinathan, Vedapriya

    2017-04-01

    The authors regret to inform that Scheme 1 in the article titled 'Synthesis, crystal structure and electrochemical and DNA binding studies of oxygen bridged-copper(II) carboxylate' in vol. 1093 of the Journal of Molecular Structure is incorrect. The corrected scheme is as shown in this correction. This is purely a copy error. The error does not affect the conclusion in paper. The authors would like to apologize for any inconvenience caused.

  9. The ability of haemolysins expressed by atypical enteropathogenic Escherichia coli to bind to extracellular matrix components

    Directory of Open Access Journals (Sweden)

    Caroline A Magalhães

    2011-03-01

    Full Text Available Typical and atypical enteropathogenic Escherichia coli (EPEC are considered important bacterial causes of diarrhoea. Considering the repertoire of virulence genes, atypical EPEC (aEPEC is a heterogeneous group, harbouring genes that are found in other diarrheagenic E. coli pathotypes, such as those encoding haemolysins. Haemolysins are cytolytic toxins that lyse host cells disrupting the function of the plasma membrane. In addition, these cytolysins mediate a connection to vascular tissue and/or blood components, such as plasma and cellular fibronectin. Therefore, we investigated the haemolytic activity of 72 aEPEC isolates and determined the correlation of this phenotype with the presence of genes encoding enterohaemolysins (Ehly and cytolysin A (ClyA. In addition, the correlation between the expression of haemolysins and the ability of these secreted proteins to adhere to extracellular matrix (ECM components was also assessed in this study. Our findings demonstrate that a subset of aEPEC presents haemolytic activity due to the expression of Ehlys and/or ClyA and that this activity is closely related to the ability of these isolates to bind to ECM components.

  10. Immunogenicity test of tetanus component in adsorbed vaccines by toxin binding inhibition test

    Directory of Open Access Journals (Sweden)

    Denise Cristina Souza Matos

    2002-09-01

    Full Text Available Samples from 20 lots of diphtheria-tetanus (adult use dT vaccine and from 20 lots of diphtheria-tetanus-pertussis (DTP vaccine were used to standardize and validate the in vitro toxin binding inhibition (ToBI test for the immunogenicity test of the tetanus component. The levels of tetanus antitoxin obtained by ToBI test were compared to those obtained using the toxin neutralization (TN test in mice routinely employed to perform the quality control of the tetanus component in adsorbed vaccines. The results ranged from 1.8 to 3.5 IU/ml for dT and 2 to 4 IU/ml for DTP by ToBI test and 1.4 to 3 IU/ml for dT and 1.8 to 3.5 IU/ml for DTP by TN in mice. These results were significantly correlated. From this study, it is concluded that the ToBI test is an alternative to the in vivo neutralization procedure in the immunogenicity test of the tetanus component in adsorbed vaccines. A substantial refinement and a reduction in use of animals can be achieved.

  11. Evaluation of IMAC and Electrospray Ionization Mass Spectrometry for Recovery and Analysis of Copper-Binding Ligands in Seawater

    Science.gov (United States)

    Nixon, R. L.; Ross, A.

    2016-02-01

    Complexation by organic ligands dominates the speciation of iron, copper, and other bioactive trace metals in seawater, controlling their bioavailability and distribution in the marine environment. Several classes of high-affinity Fe-binding ligands (siderophores) have been identified in seawater and such compounds are known to mediate iron uptake by marine bacteria, thereby influencing biological productivity in the ocean. However, little is known about the origin, structure, or ecological role of marine Cu-binding ligands (chalcophores). Immobilized metal-ion affinity chromatography (IMAC) allows selective recovery of such compounds from seawater, while electrospray ionization mass spectrometry (ESI-MS) has been used to identify marine siderophores and to characterise Cu ligands in coastal waters. Here, we use model compounds to evaluate a Cu(II)-IMAC/ESI-MS workflow for recovery and analysis of Cu-binding ligands in seawater. One-litre samples of artificial and natural filtered seawater were spiked with model Cu(II) ligands at realistic concentrations and fractionated by IMAC. Retained compounds were eluted by acidification and detected by UV absorption. Linear plots of concentration versus UV chromatographic peak area were obtained for model synthetic and natural organic ligands at concentrations ranging from 5 to 500 nM (r2=0.9988) and 50 and 750 nM (r2=0.9899), respectively, in artificial seawater. Variable though similar results were obtained for oceanic seawater spiked with 5 nM to 1 µM of ligand (r2=0.9893). Chromatographic peak data suggests that natural UV-absorbing Cu ligands are more concentrated in nearshore than in oceanic surface waters, and that these ligands are susceptible to photolysis by artificial sunlight. Eluted IMAC fractions corresponding to UV absorbance peaks were collected and different techniques evaluated for concentration and desalting of the recovered ligands prior to analysis by ESI-MS and tandem mass spectrometry (MS/MS). MS data

  12. Binding of copper(II) polypyridyl complexes to DNA and consequences for DNA-based asymmetric catalysis.

    Science.gov (United States)

    Draksharapu, Apparao; Boersma, Arnold J; Leising, Miriam; Meetsma, Auke; Browne, Wesley R; Roelfes, Gerard

    2015-02-28

    The interaction between salmon testes DNA (st-DNA) and a series of Cu(II) polypyridyl complexes, i.e. [Cu(dmbpy)(NO3)2] (1) (dmbpy = 4,4'-dimethyl-2,2'-bipyridine), [Cu(bpy)(NO3)2] (2) (bpy = 2,2'-bipyridine), [Cu(phen)(NO3)2] (3) (phen = phenanthroline), [Cu(terpy)(NO3)2]·H2O (4) (terpy = 2,2':6',2″-terpyridine), [Cu(dpq)(NO3)2] (5) (dpq = dipyrido-[3,2-d:2',3'-f]-quinoxaline) and [Cu(dppz)(NO3)2] (6) (dppz = dipyrido[3,2-a:2',3'-c]phenazine) was studied by UV/Vis absorption, Circular Dichroism, Linear Dichroism, EPR, Raman and (UV and vis) resonance Raman spectroscopies and viscometry. These complexes catalyse enantioselective C-C bond forming reactions in water with DNA as the source of chirality. Complex 1 crystallizes as an inorganic polymer with nitrate ligands bridging the copper ions, which adopt essentially a distorted square pyramidal structure with a fifth bridging nitrate ligand at the axial position. Raman spectroscopy indicates that in solution the nitrate ligands in 1, 2, 3 and 4 are displaced by solvent (H2O). For complex 1, multiple supramolecular species are observed in the presence of st-DNA in contrast to the other complexes, which appear to interact relatively uniformly as a single species predominantly, when st-DNA is present. Overall the data suggest that complexes 1 and 2 engage primarily through groove binding with st-DNA while 5 and 6 undergo intercalation. For complexes 3 and 4 the data indicates that both groove binding and intercalation takes place, albeit primarily intercalation. Although it is tempting to conclude that the groove binders give highest ee and rate acceleration, it is proposed that the flexibility and dynamics in binding of Cu(II) complexes to DNA are key parameters that determine the outcome of the reaction. These findings provide insight into the complex supramolecular structure of these DNA-based catalysts.

  13. Fatty acid and drug binding to a low-affinity component of human serum albumin, purified by affinity chromatography

    DEFF Research Database (Denmark)

    Vorum, H; Pedersen, A O; Honoré, B

    1992-01-01

    and drug binding abilities of the low-affinity component. The fatty acids decanoate, laurate, myristate and palmitate were bound with higher affinity to the mixture than to the low-affinity component. Diazepam was bound with nearly the same affinity to the low-affinity component as to the albumin mixture...... of two albumin components about 40% of the albumin having high affinity and about 60% having low affinity. By affinity chromatography we succeeded in purifying the low-affinity component from the mixture. The high-affinity component, however, could not be isolated. We further analyzed the fatty acid...

  14. Biochemical characterization of P-type copper ATPases

    Science.gov (United States)

    Inesi, Giuseppe; Pilankatta, Rajendra; Tadini-Buoninsegni, Francesco

    2014-01-01

    Copper ATPases, in analogy with other members of the P-ATPase superfamily, contain a catalytic headpiece including an aspartate residue reacting with ATP to form a phosphoenzyme intermediate, and transmembrane helices containing cation-binding sites [TMBS (transmembrane metal-binding sites)] for catalytic activation and cation translocation. Following phosphoenzyme formation by utilization of ATP, bound copper undergoes displacement from the TMBS to the lumenal membrane surface, with no H+ exchange. Although PII-type ATPases sustain active transport of alkali/alkali-earth ions (i.e. Na+, Ca2+) against electrochemical gradients across defined membranes, PIB-type ATPases transfer transition metal ions (i.e. Cu+) from delivery to acceptor proteins and, prominently in mammalian cells, undergo trafficking from/to various membrane compartments. A specific component of copper ATPases is the NMBD (N-terminal metal-binding domain), containing up to six copper-binding sites in mammalian (ATP7A and ATP7B) enzymes. Copper occupancy of NMBD sites and interaction with the ATPase headpiece are required for catalytic activation. Furthermore, in the presence of copper, the NMBD allows interaction with protein kinase D, yielding phosphorylation of serine residues, ATP7B trafficking and protection from proteasome degradation. A specific feature of ATP7A is glycosylation and stabilization on plasma membranes. Cisplatin, a platinum-containing anti-cancer drug, binds to copper sites of ATP7A and ATP7B, and undergoes vectorial displacement in analogy with copper. PMID:25242165

  15. Branchial cadmium and copper binding and intestinal cadmium uptake in wild yellow perch (Perca flavescens) from clean and metal-contaminated lakes.

    Science.gov (United States)

    Klinck, J S; Green, W W; Mirza, R S; Nadella, S R; Chowdhury, M J; Wood, C M; Pyle, G G

    2007-08-30

    Branchial binding kinetics and gastro-intestinal uptake of copper and cadmium where examined in yellow perch (Perca flavescens) from a metal-contaminated lake (Hannah Lake, Sudbury, Ontario, Canada) and an uncontaminated lake (James Lake, North Bay, Ontario, Canada). An in vivo approach was taken for gill binding comparisons while an in vitro gut binding assay was employed for gastro-intestinal tract (GIT) uptake analysis. By investigating metal uptake at the gill and the gut we cover the two main routes of metal entry into fish. Comparisons of water and sediment chemistries, metal burdens in benthic invertebrate, and metal burdens in the livers of perch from the two study lakes clearly show that yellow perch from Hannah L. are chronically exposed to a highly metal-contaminated environment compared to a reference lake. We found that metal-contaminated yellow perch showed no significant difference in gill Cd binding compared to reference fish, but they did show significant decreases in new Cd binding and absorption in their GITs. The results show that gill Cd binding may involve low-capacity, high-affinity binding sites, while gastro-intestinal Cd uptake involves binding sites that are high-capacity, low-affinity. From this we infer that Cd may be more critically controlled at the gut rather than gills. Significant differences in branchial Cu binding (increased binding) were observed in metal-contaminated yellow perch. We suggest that chronic waterborne exposure to Cu (and/or other metals) may be the dominant influence in gill Cu binding rather than chronic exposure to high Cu diets. We give supporting evidence that Cd is taken up in the GIT, at least in part, by a similar pathway as Ca(2+), principally that elevated dietary Ca(2+) reduces Cd binding and uptake. Overall our study reveals that metal pre-exposure via water and diet can alter uptake kinetics of Cu and Cd at the gill and/or the gut.

  16. Binary Component Sorption of Cadmium, and Copper Ions onto Yangtze River Sediments with Different Particle Sizes

    Directory of Open Access Journals (Sweden)

    Jianxin Fan

    2017-11-01

    Full Text Available Sorption is a crucial process that influences immobilization and migration of heavy metals in an aqueous environment. Sediments represent one of the ultimate sinks for heavy metals discharged into water body. Moreover, the particle size of sediments plays an extremely important role in the immobilization of heavy metals. In this study, the sorption and desorption of cadmium (Cd and copper (Cu onto sediments with different particle sizes were investigated to predict the rate and capacity of sorption, to understand their environmental behaviors in an aqueous environment. Batch sorption and kinetic experiments were conducted to obtain the retained amount and rate of Cd and Cu in a binary system. Experimental data were simulated using sorption models to ascertain the sorption capacity and the kinetic rate. Results of European Communities Bureau of Reference (BCR sequential extraction showed the highest concentration of Cd (0.344 mg kg−1, and its distribution varied with sediment particle size and site. Furthermore, most of Cu (approximately 57% to 84% existed as a residual fraction. The sorption of Cu onto six sediments followed a pseudo-first order reaction, whereas that of Cd followed a pseudo-second order reaction. Additionally, the competitive Langmuir model fitted the batch sorption experimental data extremely well. The highest sorption capacities of Cd and Cu reach 0.641 mmol kg−1 and 62.3 mmol kg−1, respectively, on the smallest submerged sediment particles. The amounts of Cu and Cd desorbed (mmol kg−1 increased linearly with the initial concentration increasing. Thus, sediment texture is an important factor that influences the sorption of heavy metal onto sediments.

  17. Thermodynamic Studies of Cu(I) and Other d10 Metal Ions Binding to Proteins in the Copper Homeostasis Pathway and the Organomercurial Detoxification Pathway

    Science.gov (United States)

    Stevenson, Michael James

    Copper(I) is the predominant oxidation state of this essential metal in living cells due to reducing intracellular conditions. Because of deleterious copper-mediated Fenton chemistry, intracellular copper trafficking pathways involve strict regulation by metallochaperone proteins. Previous studies of the 68-residue metallochaperone, HAH1, have shown that it coordinates Cu(I) with two cysteines for transport from Ctr1 in the cell membrane to ATPases in the Golgi network. Using isothermal titration calorimetry (ITC), and methods to suppress oxidation and disproportionation of Cu(I), the thermodynamics of Cu(I), as well as other metal ions, binding to HAH1 have been accurately quantified. During the course of this study, the Cu(I) binding thermodynamics with the stabilizing ligand hexamethyltrien were determined in order to accurately quantify the Cu(I) binding thermodynamics with proteins, and revealed an unexpected Cu(I) coordination chemistry with this ligand. In addition, HAH1 binding the Cu(I) analogue Ag(I), the abundant cellular metal ion Zn(II), and the thiophilic toxic metal ion Hg(II), have been quantified. The binding thermodynamics of these metal ions were also determined in the presence of glutathione to more accurately model physiological conditions. HAH1 has a high affinity for Cu(I), which is both enthalpically and entropically favorable. It has a substantially lower affinity for Zn(II), which is entropically favored, suggesting that Zn(II) is not able to compete with Cu(I) for HAH1 in vivo. However, HAH1 has an exceptionally high affinity for Hg(II), with its larger thiophilicity, and it will displace Cu(I). Mercury(II) and particularly organomercurial compounds are very toxic, yet proteins from the bacterial mer operon provide resistance to this toxicity. In particular, the organomercurial lyase MerB, whose only known structural homologue is a putative copper metallochaperone, is responsible for cleavage of the carbon-mercury bond of MeHg(II) and

  18. Computation of binding energies including their enthalpy and entropy components for protein-ligand complexes using support vector machines.

    Science.gov (United States)

    Koppisetty, Chaitanya A K; Frank, Martin; Kemp, Graham J L; Nyholm, Per-Georg

    2013-10-28

    Computing binding energies of protein-ligand complexes including their enthalpy and entropy terms by means of computational methods is an appealing approach for selecting initial hits and for further optimization in early stages of drug discovery. Despite the importance, computational predictions of thermodynamic components have evaded attention and reasonable solutions. In this study, support vector machines are used for developing scoring functions to compute binding energies and their enthalpy and entropy components of protein-ligand complexes. The binding energies computed from our newly derived scoring functions have better Pearson's correlation coefficients with experimental data than previously reported scoring functions in benchmarks for protein-ligand complexes from the PDBBind database. The protein-ligand complexes with binding energies dominated by enthalpy or entropy term could be qualitatively classified by the newly derived scoring functions with high accuracy. Furthermore, it is found that the inclusion of comprehensive descriptors based on ligand properties in the scoring functions improved the accuracy of classification as well as the prediction of binding energies including their thermodynamic components. The prediction of binding energies including the enthalpy and entropy components using the support vector machine based scoring functions should be of value in the drug discovery process.

  19. DNA binding, cytotoxicity and apoptosis induction activity of a mixed-ligand copper(II) complex with taurine Schiff base and imidazole

    Science.gov (United States)

    Li, Mei; kong, Lin Lin; Gou, Yi; Yang, Feng; Liang, Hong

    2014-07-01

    A novel binuclear copper(II) complex (complex 1) with taurine Schiff base and imidazole has been synthesized and structurally characterized by single crystal X-ray diffraction, elemental analysis, ESI-MS spectrometry, UV-vis and IR spectroscopy. Single-crystal analysis revealed that 1 displays the sulfonate-bridged dinuclear copper(II) centers. Both copper atoms are five-coordinated and exhibit slightly distorted square pyramidal geometries. Each of copper atom is surrounded by three oxygen atoms and one nitrogen atom from different taurine Schiff base ligands, and one nitrogen atom from one imidazole ligand. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated by UV-vis, fluorescence, circular dichroism (CD) spectra and agarose gel electrophoresis. The experimental results indicated that 1 could bind to CT-DNA via an intercalative mode and show efficient cleavage activity. In addition, 1 showed an antitumor effect on cell cycle and apoptosis. Flow cytometric analysis revealed that MGC-803 cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that 1 could induce apoptosis of MGC-803 cells.

  20. Variation in DNA binding constants with a change in geometry of ternary copper(II) complexes with N2O donor Schiff base and cyanate or dicyanamide

    Science.gov (United States)

    Jana, Subrata; Santra, Ramesh Chandra; Das, Saurabh; Chattopadhyay, Shouvik

    2014-09-01

    Two new copper(II) complexes, [Cu(L)(OCN)] (1) and [CuL(dca)]n (2), where HL = 2-(-(2-(diethylamino)ethylimino)methyl)naphthalen-1-ol, dca = N(CN)2-, have been synthesized and characterized by elemental analysis, IR, UV-VIS spectroscopy and single crystal X-ray diffraction studies. Complex 1 has square planar and complex 2 square pyramidal geometries in solid state around metal centre. Interactions of the complexes with calf thymus DNA (CT DNA) were studied by UV-VIS spectroscopy. Binding constant and site size of interaction were determined. Binding site size and intrinsic binding constant K revealed complex 1 interacted with calf thymus DNA better than complex 2.

  1. Synthesis, CMC determination, and intercalative binding interaction with nucleic acid of a surfactant-copper(II) complex with modified phenanthroline ligand (dpq).

    Science.gov (United States)

    Nagaraj, Karuppiah; Ambika, Subramanian; Arunachalam, Sankaralingam

    2015-01-01

    A surfactant-copper(II) complex, [Cu(dpq)2DA](ClO4)2 (dpq = dipyrido[3,2-d:2'-3'-f]quinoxaline; DA-dodecylamine), was synthesized and characterized on the basis of elemental analyses, UV-vis, IR, and EPR spectra. The critical micelle concentration (CMC) value of this surfactant-copper(II) complex in aqueous solution was found out from conductance measurements. Specific conductivity data at different temperature served for the evaluation of the temperature-dependent CMC and the thermodynamics of micellization (ΔG°(m), ΔH°(m) and ΔS°(m)). In addition, the complex has been examined by its ability to bind to nucleic acids (DNA and RNA) in tris-HCl buffer by UV-vis absorption, emission spectroscopy techniques, and viscosity measurements. The complex has been found to bind strongly to nucleic acids with apparent binding constants at DNA and RNA is 4.3 × 10(5), 9.0 × 10(5) M(-1), respectively. UV-vis studies of the interaction of the complex with DNA/RNA have revealed that the complex can bind to both DNA and RNA by the intercalative binding mode via ligand dpq into the base pairs of DNA and RNA which has been verified by viscosity measurements. The presence of long aliphatic chain in the surfactant complex increases this hydrophobic interaction. The binding constants have been calculated. The cytotoxic activity of this complex on human liver carcinoma cancer cells was determined by adopting 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyl tetrazolium bromide assay and specific staining techniques. The antimicrobial and antifungal screening tests of this complex have shown good results.

  2. RNA Binding Proteins in Eye Development and Disease: Implication of Conserved RNA Granule Components

    Science.gov (United States)

    Dash, Soma; Siddam, Archana D.; Barnum, Carrie E.; Janga, Sarath Chandra

    2016-01-01

    The molecular biology of metazoan eye development is an area of intense investigation. These efforts have led to the surprising recognition that although insect and vertebrate eyes have dramatically different structures, the orthologs or family members of several conserved transcription and signaling regulators such as Pax6, Six3, Prox1 and Bmp4 are commonly required for their development. In contrast, our understanding of post-transcriptional regulation in eye development and disease, particularly regarding the function of RNA binding proteins (RBPs), is limited. We examine the present knowledge of RBPs in eye development in the insect model Drosophila, as well as several vertebrate models such as fish, frog, chicken and mouse. Interestingly, of the 42 RBPs that have been investigated with for their expression or function in vertebrate eye development, 24 (~60%) are recognized in eukaryotic cells as components of RNA granules such as Processing bodies (P-bodies), Stress granules, or other specialized ribonucleoprotein (RNP) complexes. We discuss the distinct developmental and cellular events that may necessitate potential RBP/RNA granule-associated RNA regulon models to facilitate post-transcriptional control of gene expression in eye morphogenesis. In support of these hypotheses, three RBPs and RNP/RNA granule components Tdrd7, Caprin2 and Stau2 are linked to ocular developmental defects such as congenital cataract, Peters anomaly and microphthalmia in human patients or animal models. We conclude by discussing the utility of interdisciplinary approaches such as the bioinformatics tool iSyTE (integrated Systems Tool for Eye gene discovery) to prioritize RBPs for deriving post-transcriptional regulatory networks in eye development and disease. PMID:27133484

  3. Synthesis and Characterization of the Ligand Based on Benzimidazole and Its Copper Complex: DNA Binding and Antioxidant Activity

    OpenAIRE

    Wu, Huilu; Kou, Fan; Jia, Fei; Liu, Bin; Yuan, Jingkun; Bai, Ying

    2011-01-01

    A new copper(II) complex with formulae of [Cu(buobb)2](pic)2, where buobb stands for the ligand of 1,3-bis(1- butylbenzimidazol-2-yl)-2-oxopropane and pic represents 2,4,6-trinitrophenol, has been synthesized and characterized by elemental analyses, molar conductivity, IR, UV-Vis spectra measurements, and cyclic voltammetry. The crystal structure of the copper(II) complex has been determined by X-ray single-crystal diffraction. The coordination environment around each copper(II) atom can be d...

  4. EXTRACTION OF COPPER FROM LEACH LIQUOR OF METALLIC COMPONENT IN DISCARDED CELL PHONE BY CYANEX® 272

    Directory of Open Access Journals (Sweden)

    ALAFARA A. BABA

    2016-06-01

    Full Text Available Discarded cell phones contribute significantly to the amount of electronic waste generation whilst some of its components are toxic and recoverable. Also, due to the increasing demand for Cu(II in building/construction, electrical and as chemical tool in freshwater, it is imperative to develop low cost and ecofriendly technique as a substitute for the conventional treatments such as reduction-roasting route at elevated temperatures. In the present study, the hydrometallurgical operations involving leaching, solvent extraction and precipitation for the recovery of Cu(II by Cyanex® 272 in kerosene was examined. Various parameters affecting the extraction of Cu(II such as pH, extractant concentration and phase ratio were optimized. At optimal conditions, about 96.3 % Cu(II was extracted into the organic phase by 0.2 mol/L Cyanex® 272 at equilibrium pH 5.0 and aqueous to organic phase ratio 1:1. The stripping of the loaded organic was carried out by 0.1 mol/L HCl solution and stripping efficiency of 98 % was obtained. By McCabe Thiele diagram, four stages are required for complete extraction of Cu(II.

  5. Study on potential antitumor mechanism of a novel Schiff base copper(II) complex: synthesis, crystal structure, DNA binding, cytotoxicity and apoptosis induction activity.

    Science.gov (United States)

    Qiao, Xin; Ma, Zhong-Ying; Xie, Cheng-Zhi; Xue, Fei; Zhang, Yan-Wen; Xu, Jing-Yuan; Qiang, Zhao-Yan; Lou, Jian-Shi; Chen, Gong-Jun; Yan, Shi-Ping

    2011-05-01

    A new cytotoxic copper(II) complex with Schiff base ligand [Cu(II)(5-Cl-pap)(OAc)(H(2)O)]·2H(2)O (1) (5-Cl-pap=N-2-pyridiylmethylidene-2-hydroxy-5-chloro-phenylamine), was synthesized and structurally characterized by X-ray diffraction. Single-crystal analysis revealed that the copper atom shows a 4+1 pyramidal coordination, a water oxygen appears in the apical position, and three of the basal positions are occupied by the NNO tridentate ligand and the fourth by an acetate oxygen. The interaction of Schiff base copper(II) complex 1 with DNA was investigated by UV-visible spectra, fluorescence spectra and agarose gel electrophoresis. The apparent binding constant (K(app)) value of 6.40×10(5) M(-1) for 1 with DNA suggests moderate intercalative binding mode. This copper(II) complex displayed efficient oxidative cleavage of supercoiled DNA, which might indicate that the underlying mechanism involve hydroxyl radical, singlet oxygen-like species, and hydrogen peroxide as reactive oxygen species. In addition, our present work showed the antitumor effect of 1 on cell cycle and apoptosis. Flow cytometric analysis revealed that HeLa cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that complex 1 can induce apoptosis of HeLa cells, whose process was mediated by intrinsic mitochondrial apoptotic pathway owing to the activation of caspase-9 and caspase-3. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Comparing the heterogeneity of copper-binding characteristics for two different-sized soil humic acid fractions using fluorescence quenching combined with 2D-COS.

    Science.gov (United States)

    Hur, Jin; Lee, Bo-Mi

    2011-01-01

    Heterogeneous distributions of copper-binding characteristics were compared for two ultrafiltered size fractions of a soil HA using fluorescence quenching combined with two-dimensional correlation spectroscopy (2D-COS). The apparent shapes of the original synchronous fluorescence spectra and the extent of the fluorescence quenching upon the addition of copper were similar for the two fractions. The stability constants calculated at their highest peaks were not significantly different. However, the 2D-COS results revealed that the fluorescence quenching behaviors were strongly affected by the associated wavelengths and the fraction's size. The spectral change preferentially occurred in the wavelength order of 467 nm → 451 nm → 357 nm for the 1-10 K fraction and of 376 nm → 464 nm for the >100 K fraction. The extent of the binding affinities exactly followed the sequential orders interpreted from the 2D-COS, and they exhibited the distinctive ranges of the logarithmic values from 5.86 to 4.91 and from 6.48 to 5.95 for the 1-10 K and the >100 K fractions, respectively. Our studies demonstrated that fluorescence quenching combined with 2D-COS could be successfully utilized to give insight into the chemical heterogeneity associated with metal-binding sites within the relatively homogeneous HA size fractions.

  7. Mannose binding lectin enhances IL-1beta and IL-10 induction by non-lipopolysaccharide (LPS) components of Neisseria meningitidis.

    NARCIS (Netherlands)

    Sprong, T.; Jack, D.L.; Klein, N.J.; Turner, M.W.; Ley, P. van der; Steeghs, L.; Jacobs, L.; Meer, J.W.M. van der; Deuren, M. van

    2004-01-01

    Mannose binding lectin (MBL) is a key molecule in the lectin pathway of complement activation, and likely of importance in our innate defence against meningococcal infection. We evaluated the role of MBL in cytokine induction by LPS or non-LPS components of Neisseria meningitidis, using a

  8. Microstructural and component evolution of self-assembled nanoperiod multilayered carbon-copper films with deposition pressure

    Directory of Open Access Journals (Sweden)

    Weiqi Wang

    2017-04-01

    Full Text Available Here, we report a facile synthesis method for the fabrication of various nanoperiod multilayers in carbon-copper films only by conveniently changing the deposition pressure from the reactive magnetron sputter process. To obtain the nano-multilayered structure with different number of layers, only one single sputtering target of copper is used at gas pressure varied from 0.4 Pa to 1.2 Pa by flowing gas mixture of argon and methane, while 600W DC input power is applied to a copper target. The influence of deposition pressure on the microstructure and constitution of the films are investigated by X-ray photoelectron spectroscopy (XPS, field emission scanning electron microscopy (FESEM and high-resolution transmission electron microscopy (HRTEM. The results show that carbon-rich layers and copper-rich layers are alternately arranged to self-organize the multilayered structure in the carbon-copper films, both of the carbon-rich layer and copper-rich layer constitute a period. The amount of layers in the multilayered structure is found to decrease with the deposition pressure, the film deposited with 0.4 Pa has the maximum layers and the highest copper content compared with the other deposition pressure. Effects of the growth condition on the growth rate, the number of the layers and the energy of plasmas during deposition process are discussed. Based on the (a influence of the effect of carbon absorbed on the copper target leading to target poisoning, (b influence of deposition pressure on the energy of etching ions and (c the energetic ions bombardment enhanced inter diffusion of deposition ions, the mechanism of self-organized formation of nano-multilayer in the carbon-copper films with various number of layer is proposed.

  9. Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines

    Science.gov (United States)

    Ravichandran, J.; Gurumoorthy, P.; Imran Musthafa, M. A.; Kalilur Rahiman, A.

    2014-12-01

    A series of heteroleptic copper(II) complexes of the type [CuL1-4(diimine)](ClO4)2 (1-8) [L1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2‧-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172 × 10-4 cm-1) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in dx-y ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA.

  10. A copper-activated two-component system interacts with zinc and imipenem resistance in Pseudomonas aeruginosa.

    Science.gov (United States)

    Caille, Olivier; Rossier, Claude; Perron, Karl

    2007-07-01

    The effects of copper (Cu) on trace metal and antibiotic resistance of Pseudomonas aeruginosa have been investigated. Cu treatments induced resistance not only to this metal but also, surprisingly, to zinc (Zn). Quantitative reverse transcription-PCR (qRT-PCR) revealed that after Cu treatment the transcription of the czcRS two-component system (TCS) operon was enhanced as well as that of the czcCBA operon encoding an efflux pump specific for zinc, cadmium, and cobalt. Cu treatments at the same time caused a decrease in the production of OprD porin, resulting in resistance to the carbapenem antibiotic imipenem. The CzcR regulator was known to repress oprD. However, Cu was still able to decrease the production of OprD and induce imipenem resistance in a czcRS knockout mutant. This strongly suggested that another Cu-dependent regulatory system was acting negatively on oprD expression. TCS regulator genes copR-copS have been shown to be involved in Cu tolerance in P. aeruginosa. qRT-PCR showed that overproduction of the CopR or of the CzcR regulator resulted in increased transcription of the czcC gene as well as in a decrease in oprD gene transcription, either in the wild-type strain or in the czcRS knockout mutant. Overproduction experiments suggest that a metal-dependent mechanism operates at the posttranscriptional level to control the production of the CzcCBA efflux pump. This study shows that CopR is a new negative regulator of OprD porin and that it links Zn, Cu, and imipenem resistances by interacting with the CzcRS TCS.

  11. Environment of copper in Pseudomonas aeruginosa azurin probed by binding of exogenous ligands to Met121X (X = Gly, Ala, Val, Leu, or Asp) mutants.

    Science.gov (United States)

    Bonander, N; Karlsson, B G; Vänngård, T

    1996-02-20

    The binding of small exogenous ligands to mutants of the blue copper protein azurin from Pseudomonas aeruginosa, altered in the axial position, Met121X (X = Gly, Ala, Val, Leu, or Asp), has been studied with optical and electron paramagnetic resonance (EPR) spectroscopy. The results show that small molecules can enter the pocket left by the side chain of Met121. For azide, the dissociation constants are Leu > Val > Ala, reflecting the increasing space available. The Gly and Asp mutants bind azide less strongly than the Ala mutant, due to competition with water (Gly) and the polar side chain (Asp). Similar trends are found for thiocyanate. Cyanide binds equally well to the Ala and Val mutants. A number of other small potential ligands were tried. Alcohols do not affect room-temperature optical spectra, but at low temperatures, the EPR spectrum is stellacyanin-like, indicative of a weak axial interaction. Ligands binding with a carboxyl group or nitrogen (e.g. acetate or azide) convert the metal center to a form intermediate between regular types 1 and 2, presumably by pulling the copper ion out of the trigonal plane formed by Cys(S) and two His(N). Cyanide interacts strongly as shown by the hyperfine coupling to the 13C nucleus. With increasing strength of the axial interaction, the two major bands in the visible region (600 and 400-500 nm) shift in parallel to higher energy, and at the same time, the strength of the latter transition increases at the expense of the former. This demonstrates that these transitions have a common origin, namely S-to-Cu charge transfer transition.

  12. Fluorescence Quenching Property of C-Phycocyanin from Spirulina platensis and its Binding Efficacy with Viable Cell Components.

    Science.gov (United States)

    Paswan, Meenakshi B; Chudasama, Meghna M; Mitra, Madhusree; Bhayani, Khushbu; George, Basil; Chatterjee, Shruti; Mishra, Sandhya

    2016-03-01

    Phycocyanin is a natural brilliant blue colored, fluorescent protein, which is commonly present in cyanobacteria. In this study, C-phycocyanin was extracted and purified from Spirulina platensis, which are multicellular and filamentous cyanobacteria of greater importance because of its various biological and pharmacological potential. It was analyzed for its binding affinity towards blood cells, algal cells, genomic DNA of microalgae, and bacteria at different temperature and incubation time. It showed good binding affinity with these components even at low concentration of 2.5 μM. The purpose of this study was to evaluate the applicability of C-phycocyanin as a green fluorescent dye substituting carcinogenic chemical dyes.

  13. New insights into metal interactions with the prion protein: EXAFS analysis and structure calculations of copper binding to a single octarepeat from the prion protein.

    Science.gov (United States)

    McDonald, Alex; Pushie, M Jake; Millhauser, Glenn L; George, Graham N

    2013-11-07

    Copper coordination to the prion protein (PrP) has garnered considerable interest for almost 20 years, due in part to the possibility that this interaction may be part of the normal function of PrP. The most characterized form of copper binding to PrP has been Cu(2+) interaction with the conserved tandem repeats in the N-terminal domain of PrP, termed the octarepeats, with many studies focusing on single and multiple repeats of PHGGGWGQ. Extended X-ray absorption fine structure (EXAFS) spectroscopy has been used in several previous instances to characterize the solution structure of Cu(2+) binding into the peptide backbone in the HGGG portion of the octarepeats. All previous EXAFS studies, however, have benefitted from crystallographic structure information for [Cu(II) (Ac-HGGGW-NH2)(-2H)] but have not conclusively demonstrated that the complex EXAFS spectrum represents the same coordination environment for Cu(2+) bound to the peptide backbone. Density functional structure calculations as well as full multiple scattering EXAFS curve fitting analysis are brought to bear on the predominant coordination mode for Cu(2+) with the Ac-PHGGGWGQ-NH2 peptide at physiological pH, under high Cu(2+) occupancy conditions. In addition to the structure calculations, which provide a thermodynamic link to structural information, methods are also presented for extensive deconvolution of the EXAFS spectrum. We demonstrate how the EXAFS data can be analyzed to extract the maximum structural information and arrive at a structural model that is significantly improved over previous EXAFS characterizations. The EXAFS spectrum for the chemically reduced form of copper binding to the Ac-PHGGGWGQ-NH2 peptide is presented, which is best modeled as a linear two-coordinate species with a single His imidazole ligand and a water molecule. The extent of in situ photoreduction of the copper center during standard data collection is also presented, and EXAFS curve fitting of the photoreduced species

  14. Cadmium binding components in the supernatant fraction of the small intestinal mucosa of rats administered cadmium

    International Nuclear Information System (INIS)

    Taguchi, Tetsuya; Suzuki, Shosuke

    1978-01-01

    Cadmium binding protein was isolated by gel filtration from the supernatant fraction of the small intestines of rats continuously administered cadmium for 1, 3, 6, 9, 32 and 96 days. About two-thirds of the total amount of absorbed cadmium was associated with the cytosol of mucosal tissues scraped from the small intestines. Cadmium was almost always bound to proteins, molecular weights of which ranged from 5,400 to 9,800. Cadmium in livers and that in intestinal mucosa were in the same binding state, but as there was some lag period between the induction of the Cd-binding proteins of both tissues, the protein of the small intestinal mucosal cells must have been induced at the mucosa itself by contact with cadmium. The Cd-binding protein of the mucosal cells may play an important role in absorbing cadmium, because no other form of this metal was found in the mucosal cells of the small intestines. (Kobatake, H.)

  15. Characterization of the Ptychodiscus brevis Polyether Neurotoxin Binding Component in Excitable Membranes

    Science.gov (United States)

    1986-07-31

    and a solvent system consisting of CHCl 3 /’MeOH/trifluoroacetic acid (100/10/1). Saxitoxin was obtained from the FDA, batrachotoxin from NIH, and sea...and batrachotoxin benzoate (50-70 nM). Specific binding is saturable and Is relatively membrane- potential independent; there beinq a...their activity by sodium channel activators would be expected. In fact, tritiated batrachotoxin benzoate binding is enhanced up to 5-fold in the

  16. Spectroscopic characterization of effective components anthraquinones in Chinese medicinal herbs binding with serum albumins

    Science.gov (United States)

    Bi, Shuyun; Song, Daqian; Kan, Yuhe; Xu, Dong; Tian, Yuan; Zhou, Xin; Zhang, Hanqi

    2005-11-01

    The interactions of serum albumins such as human serum albumin (HSA) and bovine serum albumin (BSA) with emodin, rhein, aloe-emodin and aloin were assessed employing fluorescence quenching and absorption spectroscopic techniques. The results obtained revealed that there are relatively strong binding affinity for the four anthraquinones with HSA and BSA and the binding constants for the interactions of anthraquinones with HSA or BSA at 20 °C were obtained. Anthraquinone-albumin interactions were studied at different temperatures and in the presence of some metal ions. And the competition binding of anthraquinones with serum albumins was also discussed. The Stern-Volmer curves suggested that the quenching occurring in the reactions was the static quenching process. The binding distances and transfer efficiencies for each binding reactions were calculated according to the Föster theory of non-radiation energy transfer. Using thermodynamic equations, the main action forces of these reactions were also obtained. The reasons of the different binding affinities for different anthraquinone-albumin reactions were probed from the point of view of molecular structures.

  17. The tachykinin peptide neurokinin B binds copper(I) and silver(I) and undergoes quasi-reversible electrochemistry: towards a new function for the peptide in the brain.

    Science.gov (United States)

    Grosas, Aidan B; Kalimuthu, Palraj; Smith, Alison C; Williams, Peter A; Millar, Thomas J; Bernhardt, Paul V; Jones, Christopher E

    2014-05-01

    The tachykinin neuropeptide family, which includes substance P and neurokinin B, is involved in a wide array of biological functions. Among these is the ability to protect against the neurotoxic processes in Alzheimer's Disease, but the mechanisms driving neuroprotection remain unclear. Dysregulation of metal ions, particularly copper, iron and zinc is a common feature of Alzheimer's Disease, and other amyloidogenic disorders. Copper is known to be released from neurons and recent work has shown that some tachykinins can bind Cu(II) ions, and that neurokinin B can inhibit copper uptake into astrocytes. We have now examined whether neurokinin B is capable of binding Cu(I), which is predicted to be available in the synapse. Using a combination of spectroscopic techniques including cyclic voltammetry and magnetic resonance we show that neurokinin B can bind Cu(I) either directly from added CuCl or by reduction of Cu(II)-bound neurokinin B. The results showed that the Cu(I) binding site differs greatly to that of Cu(II) and involves thioether coordination via Met2 and Met10 and an imidazole nitrogen ligand from His3. The Cu(I) coordination is also different to the site adopted by Ag(I). During changes in oxidation state, copper remains bound to neurokinin B despite large changes to the inner coordination sphere. We predict that neurokinin B may be involved in synaptic copper homeostasis. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Synthesis, molecular docking and DNA binding studies of phthalimide-based copper(II) complex: In vitro antibacterial, hemolytic and antioxidant assessment

    Science.gov (United States)

    Arif, Rizwan; Nayab, Pattan Sirajuddin; Ansari, Istikhar A.; Shahid, M.; Irfan, Mohammad; Alam, Shadab; Abid, Mohammad; Rahisuddin

    2018-05-01

    In the present research work, we prepared N-substituted phthalimide, 2-(-(2-(2-(2-(1,3-dioxoisoindoline-2-yl-ethylamino)ethylamino)ethyl)isoindoline-1,3-dione (DEEI) and its copper(II) complex. The ligand (DEEI) and its Cu(II) complex were structurally identified using absorption, FTIR, NMR, electron spin resonance, X-ray diffraction spectral studies, thermogravimetric and elemental analyses. The electronic spectrum and magnetic moment value proposed that Cu(II) complex has square planar geometry. The DNA interaction ability of the ligand (DEEI) and Cu(II) complex was studied by means of absorption and fluorescence spectrophotometer, viscosity measurements, cyclic voltammetery, and circular dichroism methods. The extent of DNA binding (Kb) with Calf thymus (Ct-DNA) follows the order of Cu(II) complex (1.11 × 106 M-1) > DEEI (1.0 × 105 M-1), indicating that Cu(II) complex interact with Ct-DNA through groove binding mode and more sturdily than ligand (DEEI). Interestingly, in silico predictions were corroborated with in vitro DNA binding studies. The antibacterial evaluation of these compounds was screened against a panel of bacterial strains Pseudomonas aeruginosa (MTCC 2453), Salmonella enterica (MTCC 3224), Streptococcus pneumoniae (MTCC 655), Enterococcus faecalis (MTCC 439), Klebsiella pneumonia and Escherichia coli (ATCC 25922). The results showed that the copper(II) complex has significant antibacterial potential (IC50 = 0.0019 μg/mL) against Salmonella enteric comparable with ligand (DEEI) and standard drug ciprofloxacin. Growth curve study of Cu(II) complex against only three bacterial strains S. enterica, E. faecalis and S. pneumoniae showed its bactericidal nature. Cu(II) complex showed less than 2% hemolysis on human RBCs indicating its non toxic nature. The results of antioxidant assay demonstrated that scavenging activity of Cu(II) complex is higher as compared to ligand and ascorbic acid as standard.

  19. Lights and shadows in the challenge of binding acyclovir, a synthetic purine-like nucleoside with antiviral activity, at an apical-distal coordination site in copper(II)-polyamine chelates.

    Science.gov (United States)

    Pérez-Toro, Inmaculada; Domínguez-Martín, Alicia; Choquesillo-Lazarte, Duane; Vílchez-Rodríguez, Esther; González-Pérez, Josefa María; Castiñeiras, Alfonso; Niclós-Gutiérrez, Juan

    2015-07-01

    Several nucleic acid components and their metal complexes are known to be involved in crucial metabolic steps. Therefore the study of metal-nucleic acid interactions becomes essential to understand these biological processes. In this work, the synthetic purine-like nucleoside acyclovir (acv) has been used as a model of guanosine recognition with copper(II)-polyamine chelates. The chemical stability of the N9-acyclic arm in acv offers the possibility to use this antiviral drug to deepen the knowledge of metal-nucleoside interactions. Cu(II) chelates with cyclam, cyclen and trien were used as suitable receptors. All these copper(II) tetraamine chelates have in common the potential ability to yield a Cu-N7(apical) bond assisted by an appropriate (amine)N-H⋯O6(acv) intra-molecular interligand interaction. A series of synthesis afforded the following compounds: [Cu(cyclam)(ClO4)2] (1), {[Cu(cyclam)(μ2-NO3)](NO3)}n (2), {[Cu(cyclam)(μ2-SO4)]·MeOH}n (3), {[Cu(cyclam)(μ2-SO4)]·5H2O}n (4), [Cu(cyclen)(H2O)]SO4·2H2O (5), [Cu(cyclen)(H2O)]SO4·3H2O (6), [Cu(trien)(acv)](NO3)2·acv (7) and [Cu(trien)(acv)]SO4·0.71H2O (8). All these compounds have been characterized by X-ray crystallography and FT-IR spectroscopy. Our results reveal that the macrochelates Cu(cyclen)(2+) and Cu(cyclam)(2+) are unable to bind acv at an apical site. In contrast, the Cu(trien)(2+) complex has proved to be an efficient receptor for acv in compounds (7) and (8). In the ternary complex [Cu(trien)(acv)](2+), the metal binding pattern of acv consists of an apical Cu-N7 bond assisted by an intra-molecular (primary amino)N-H⋯O6(acv) interligand interaction. Structural comparisons reveal that this unprecedented apical role of acv is due to the acyclic nature of trien together with the ability of the Cu(trien)(2+) chelate to generate five-coordinated (type 4+1) copper(II) complexes. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Sonochemical Synthesis and Characterization of the Copper(II) Nanocomplex: DNA- and BSA-Binding, Cell Imaging, and Cytotoxicity Against the Human Carcinoma Cell Lines.

    Science.gov (United States)

    Anjomshoa, Marzieh; Torkzadeh-Mahani, Masoud; Dashtrazmi, Ebrahim; Adeli-Sardou, Mahboubeh

    2016-03-01

    The focus of the present work is the preparation of new metal-based nanodrug to overcome limitations of chemotherapy such as poor water solubility of most common chemotherapeutic drugs. The copper(II) complex of 1,2,4-triazine derivatives, [Cu(dppt)2(H2O)2](2+) (dppt is 5,6-diphenyl- 3- (2-pyridyl)-1,2,4-triazine), has been synthesized at nano-size by sonochemical method and characterized by FTIR, zetasizer, and scanning electron microscopy (SEM). The interaction of the complex and nanocomplex with fish sperm DNA (FS-DNA) and BSA have been investigated under physiological conditions by a series of experimental methods. The results have indicated that the complex binds to FS-DNA by two biding modes, viz., electrostatic and intercalates into the base pairs of DNA. The competitive study with ethidium bromide (EB) shows that the complex and nanocomplex competes for the DNA-binding sites with EB. Protein binding studies show that the complex and nanocomplex could bind with BSA. The results of synchronous fluorescence of BSA show that additions of the complex affect the microenvironment of both tyrosine and tryptophan residues during the binding process. The in vitro cytotoxicity of the complex (solution in DMSO) and nanocomplex (colloid in H2O) against the human carcinoma cell lines (MCF-7 and A-549) was evaluated by MTT assay. The results of in vitro cytotoxicity indicate that the complex and nanocomplex have excellent cytotoxicity activity against MCF-7 and A-549. Results of the microscopic analyses of the cancer cells confirm the results of the cytotoxicity.

  1. Proteomic Analysis of Copper-Binding Proteins in Excess Copper-Stressed Roots of Two Rice (Oryza sativa L. Varieties with Different Cu Tolerances.

    Directory of Open Access Journals (Sweden)

    Chen Chen

    Full Text Available To better understand the mechanisms involved in the heavy metal stress response and tolerance in plants, a proteomic approach was used to investigate the differences in Cu-binding protein expression in Cu-tolerant and Cu-sensitive rice varieties. Cu-binding proteins from Cu-treated rice roots were separated using a new IMAC method in which an IDA-sepharose column was applied prior to the Cu-IMAC column to remove metal ions from protein samples. More than 300 protein spots were reproducibly detected in the 2D gel. Thirty-five protein spots exhibited changes greater than 1.5-fold in intensity compared to the control. Twenty-four proteins contained one or more of nine putative metal-binding motifs reported by Smith et al., and 19 proteins (spots contained one to three of the top six motifs reported by Kung et al. The intensities of seven protein spots were increased in the Cu-tolerant variety B1139 compared to the Cu-sensitive variety B1195 (p<0.05 and six protein spots were markedly up-regulated in B1139, but not detectable in B1195. Four protein spots were significantly up-regulated in B1139, but unchanged in B1195 under Cu stress. In contrast, two protein spots were significantly down-regulated in B1195, but unchanged in B1139. These Cu-responsive proteins included those involved in antioxidant defense and detoxification (spots 5, 16, 21, 22, 28, 29 and 33, pathogenesis (spots 5, 16, 21, 22, 28, 29 and 33, regulation of gene transcription (spots 8 and 34, amino acid synthesis (spots 8 and 34, protein synthesis, modification, transport and degradation (spots 1, 2, 4, 10, 15, 19, 30, 31, 32 and 35, cell wall synthesis (spot 14, molecular signaling (spot 3, and salt stress (spots 7, 9 and 27; together with other proteins, such as a putative glyoxylate induced protein, proteins containing dimeric alpha-beta barrel domains, and adenosine kinase-like proteins. Our results suggest that these proteins, together with related physiological processes, play

  2. DNA interaction studies of a copper (II) complex containing an antiviral drug, valacyclovir: the effect of metal center on the mode of binding.

    Science.gov (United States)

    Shahabadi, Nahid; Fatahi, Parvin

    2012-07-01

    The water-soluble complex, [Cu(Val)(2)(NO(3))(2)]; in which Val = valacyclovir, an antiviral drug, has been synthesized and characterized by elemental analysis, furier transfer-infrared, hydrogen nuclear magnetic resonance (H NMR), and UV-Vis techniques. The binding of this Cu (II) complex to calf thymus DNA was investigated using fluorimetry, spectrophotometry, circular dichroism, and viscosimetry. In fluorimetric studies, the enthalpy and entropy of the reaction between the complex and calf-thymus DNA (CT-DNA) showed that the reaction is endothermic (ΔH = 208.22 kJ mol(-1); ΔS = 851.35 J mol(-1)K(-1)). The complex showed the absorption hyperchromism in its ultra violet-visible (UV-Vis) spectrum with DNA. The calculated binding constant, K(b), obtained from UV-Vis absorption studies was 2 × 10(5) M(-1). Moreover, the complex induced detectable changes in the circular dichroism spectrum of CT-DNA, as well as changes in its viscosity. The results suggest that this copper (II) complex interacts with CT-DNA via a groove-binding mode.

  3. Telomere repeat binding proteins are functional components of Arabidopsis telomeres and interact with telomerase

    Czech Academy of Sciences Publication Activity Database

    Schrumpfová, P.; Vychodilová, I.; Dvořáčková, Martina; Majerská, J.; Dokládal, Ladislav; Schorová, Š.; Fajkus, Jiří

    2014-01-01

    Roč. 77, č. 5 (2014), s. 770-781 ISSN 0960-7412 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0068; GA ČR(CZ) GA13-06943S Institutional support: RVO:68081707 Keywords : telomere protein interaction * telomere repeat binding * Arabidopsis thaliana Subject RIV: BO - Biophysics Impact factor: 5.972, year: 2014

  4. Structural Characterization of Natural Nickel and Copper Binding Ligands along the US GEOTRACES Eastern Pacific Zonal Transect

    OpenAIRE

    Boiteau, Rene M.; Till, Claire P.; Ruacho, Angel; Bundy, Randelle M.; Hawco, Nicholas J.; McKenna, Amy M.; Barbeau, Katherine A.; Bruland, Kenneth W.; Saito, Mak A.; Repeta, Daniel J.

    2016-01-01

    Organic ligands form strong complexes with many trace elements in seawater. Various metals can compete for the same ligand chelation sites, and the final speciation of bound metals is determined by relative binding affinities, concentrations of binding sites, uncomplexed metal concentrations, and association/dissociation kinetics. Different ligands have a wide range of metal affinities and specificities. However, the chemical composition of these ligands in the marine environment remains poor...

  5. Structural characterization of natural nickel and copper binding ligands along the US GEOTRACES Eastern Pacific Zonal transect

    OpenAIRE

    Rene M Boiteau; Rene M Boiteau; Claire P Till; Angel Ruacho; Randelle M Bundy; Nicholas J Hawco; Nicholas J Hawco; Amy M. McKenna; Katherine Barbeau; Kenneth Bruland; Mak Saito; Daniel James Repeta

    2016-01-01

    Organic ligands form strong complexes with many trace elements in seawater. Various metals can compete for the same ligand chelation sites, and the final speciation of bound metals is determined by relative binding affinities, concentrations of binding sites, uncomplexed metal concentrations, and association/dissociation kinetics. Different ligands have a wide range of metal affinities and specificities. However, the chemical composition of these ligands in the marine environment remains poor...

  6. Synthesis, DNA binding and cleavage activities of copper (II) thiocyanate complex with 4-(N,N-dimethylamino)pyridine and N,N-dimethylformamide.

    Science.gov (United States)

    Chen, Feng-juan; Xu, Min; Xi, Pin-xian; Liu, Hong-yang; Zeng, Zheng-zhi

    2011-10-15

    Two novel copper(II) thiocyanate complexes with 4-(N,N-dimethylamino) pyridine and N,N-dimethylformamide (1) and with 4-(N,N-dimethylamino) pyridine (2) have been synthesized and characterized. The crystal and molecular structures of complexes 1 and 2 were determined by single-crystal X-ray diffraction. Antioxidative activity tests in vitro showed that complex 1 has significant antioxidative activity against hydroxyl free radicals from the Fenton reaction and also oxygen free radicals, which is better than standard antioxidants like vitamin C and mannitol. The interaction of complex 1 with calf thymus DNA was investigated by spectroscopic, cyclic voltammetry, and viscosity measurements. Results suggest that complex 1 can bind to DNA via partial intercalation mode. Moreover, complex 1 has been found to cleavage of plasmid DNA pBR322. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. A Purple Cupredoxin from Nitrosopumilus maritimus Containing a Mononuclear Type 1 Copper Center with an Open Binding Site

    Energy Technology Data Exchange (ETDEWEB)

    Hosseinzadeh, Parisa; Tian, Shiliang; Marshall, Nicholas M.; Hemp, James; Mullen, Timothy; Nilges, Mark J.; Gao, Yi-Gui; Robinson, Howard; Stahl, David A.; Gennis, Robert B.; Lu, Yi

    2016-05-25

    Mononuclear cupredoxin proteins usually contain a coordinately saturated type 1 copper (T1Cu) center and function exclusively as electron carriers. Here we report a cupredoxin isolated from the nitrifying archaeon Nitrosopumilus maritimus SCM1, called Nmar1307, that contains a T1Cu center with an open binding site containing water. It displays a deep purple color due to strong absorptions around 413 nm (1880 M–1 cm–1) and 558 nm (2290 M–1 cm–1) in the UV–vis electronic spectrum. EPR studies suggest the protein contains two Cu(II) species of nearly equal population, one nearly axial, with hyperfine constant A∥ = 98 × 10–4 cm–1, and another more rhombic, with a smaller A∥ value of 69 × 10–4 cm–1. The X-ray crystal structure at 1.6 Å resolution confirms that it contains a Cu atom coordinated by two His and one Cys in a trigonal plane, with an axial H2O at 2.25 Å. Both UV–vis absorption and EPR spectroscopic studies suggest that the Nmar1307 can oxidize NO to nitrite, an activity that is attributable to the high reduction potential (354 mV vs SHE) of the copper site. These results suggest that mononuclear cupredoxins can have a wide range of structural features, including an open binding site containing water, making this class of proteins even more versatile.

  8. Synthesis, spectroscopic characterization and antimicrobial activity of binuclear metal complexes of a new asymmetrical Schiff base ligand: DNA binding affinity of copper(II) complexes

    Science.gov (United States)

    Shebl, Magdy

    2014-01-01

    The 1:1 condensation of o-acetoacetylphenol and 1,2-diaminopropane under condition of high dilution gives the mono-condensed Schiff base, (E)-3-(1-aminopropan-2-ylimino)-1-(2-hydroxyphenyl)butan-1-one. The mono-condensed Schiff base has been used for further condensation with isatin to obtain the new asymmetrical dicompartmental Schiff base ligand, (E)-3-(2-((E)-4-(2-hydroxyphenyl)-4-oxobutan-2-ylideneamino) propylimino)indolin-2-one (H3L) with a N2O3 donor set. Reactions of the ligand with metal salts give a series of new binuclear complexes. The ligand and its metal complexes were characterized by elemental analyses, IR, 1H and 13C NMR, electronic, ESR and mass spectra, conductivity and magnetic susceptibility measurements as well as thermal analyses. The analytical and spectroscopic tools showed that the complexes can be formulated as: [(HL)(VO)2(SO4)(H2O)]·4H2O, [(HL)Fe2Cl4(H2O)3]·EtOH, [(HL)Fe2(ox)Cl2(H2O)3]·2H2O, [(L)M2(OAc)(H2O)m]·nH2O; M = Co, Ni or Cu, m = 4, 0 and n = 2, 3, [(HL)Cu2Cl]Cl·6H2O and [(L)(UO2)2(OAc)(H2O)3]·6H2O. The metal complexes exhibited octahedral geometrical arrangements except copper complexes that exhibited tetrahedral geometries and uranyl complex in which the metal ion is octa-coordinated. The Schiff base and its metal complexes were evaluated for antimicrobial activity against Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli) and fungi (Candida albicans and Aspergillus flavus). The ligand and some of its complexes were found to be biologically active. The DNA-binding properties of the copper complexes (6 and 7) have been investigated by electronic absorption, fluorescence and viscosity measurements. The results obtained indicate that these complexes bind to DNA via an intercalation binding mode with an intrinsic binding constant, Kb of 1.34 × 104 and 2.5 × 104 M-1, respectively.

  9. Copper(i) catalyzed oxidative hydrolysis of Ugi 3-component and Ugi-azide reaction products towards 2° α-ketoamides and α-ketotetrazoles.

    Science.gov (United States)

    Collet, Jurriën W; Foley, Christopher; Shaw, Arthur Y; Orru, Romano V A; Ruijter, Eelco; Hulme, Christopher

    2017-07-26

    Herein, a two-step MCR-oxidation methodology accessing decorated 2° α-ketoamides and α-ketotetrazoles is described via a catalytic copper(i)-mediated C-N oxidation/acidic hydrolysis of Ugi-three-component and Ugi-azide reaction products. The ability to install diversity from aldehyde and isocyanide synthons allows rapid complexity generation. Of note, (1) 2° α-ketoamides are traditionally difficult to access and more so reminiscent of the endogenous peptide bonds. (2) The route to α-keto-tetrazoles is significantly shorter than that in previous reports.

  10. Effect of Binding Components in Complex Sample Matrices on Recovery in Direct Immersion Solid-Phase Microextraction: Friends or Foe?

    Science.gov (United States)

    Alam, Md Nazmul; Pawliszyn, Janusz

    2018-02-20

    The development of matrix compatible coatings for solid-phase microextraction (SPME) has enabled direct extraction of analytes from complex sample matrices. The direct immersion (DI) mode of SPME when utilized in conjunction with such extraction phases facilitates extraction of a wide range of analytes from complex matrices without the incurrence of fouling or coating saturation. In this work, mathematical models and computational simulations were employed to investigate the effect of binding components present in complex samples on the recovery of small molecules varying in logP for extractions carried out using the direct immersion approach. The presented findings corroborate that the studied approach indeed enables the extraction of both polar and nonpolar analytes from complex matrices, provided a suitable sorbent is employed. Further results indicated that, in certain cases, the kinetics of extraction of a given analyte in its free form might be dependent on the desorption kinetics of their bound form from matrix components, which might lower total recoveries of analytes with high affinity for the matrix. However, the binding of analytes to matrix components also enables SPME to extract a balanced quantity of different logP analytes, facilitated by multiphase equilibria, with a single extraction device.

  11. Reaction of some macrolide antibiotics with the ribosome. Labeling of the binding site components

    International Nuclear Information System (INIS)

    Tejedor, F.; Ballesta, J.P.

    1986-01-01

    Radioactive carbomycin A, niddamycin, tylosin, and spiramycin, but not erythromycin, can be covalently bound to Escherichia coli ribosomes by incubation at 37 degrees C. The incorporation of radioactivity into the particles is inhibited by SH- and activated double bond containing compounds but not by amino groups, suggesting that the reactions may take place by addition to the double bond present in the reactive antibiotics. This thermic reaction must be different from the photoreaction described for some of these macrolides [Tejedor, F., and Ballesta, J. P. G. (1985) Biochemistry 24, 467-472] since tylosin, which is not photoincorporated, is thermically bound to ribosomes. Most of the radioactivity is incorporated into the ribosomal proteins. Two-dimensional gel electrophoresis of proteins labeled by carbomycin A, niddamycin, and tylosin indicates that about 40% of the radioactivity is bound to protein L27; the rest is distributed among several other proteins such as L8, L2, and S12, to differing extents depending on the drug used. These results indicate, in accordance with previous data, that protein L27 plays an important role in the macrolide binding site, confirming that these drugs bind near the peptidyl transferase center of the ribosome

  12. Reaction of some macrolide antibiotics with the ribosome. Labeling of the binding site components

    Energy Technology Data Exchange (ETDEWEB)

    Tejedor, F.; Ballesta, J.P.

    1986-11-18

    Radioactive carbomycin A, niddamycin, tylosin, and spiramycin, but not erythromycin, can be covalently bound to Escherichia coli ribosomes by incubation at 37 degrees C. The incorporation of radioactivity into the particles is inhibited by SH- and activated double bond containing compounds but not by amino groups, suggesting that the reactions may take place by addition to the double bond present in the reactive antibiotics. This thermic reaction must be different from the photoreaction described for some of these macrolides (Tejedor, F., and Ballesta, J. P. G. (1985) Biochemistry 24, 467-472) since tylosin, which is not photoincorporated, is thermically bound to ribosomes. Most of the radioactivity is incorporated into the ribosomal proteins. Two-dimensional gel electrophoresis of proteins labeled by carbomycin A, niddamycin, and tylosin indicates that about 40% of the radioactivity is bound to protein L27; the rest is distributed among several other proteins such as L8, L2, and S12, to differing extents depending on the drug used. These results indicate, in accordance with previous data, that protein L27 plays an important role in the macrolide binding site, confirming that these drugs bind near the peptidyl transferase center of the ribosome.

  13. Chromatin-independent binding of serum amyloid P component to apoptotic cells

    NARCIS (Netherlands)

    Familian, A.; Zwart, B.; Huisman, H. G.; Rensink, I.; Roem, D.; Hordijk, P. L.; Aarden, L. A.; Hack, C. E.

    2001-01-01

    Human serum amyloid P component (SAP) is a glycoprotein structurally belonging to the pentraxin family of proteins, which has a characteristic pentameric organization. Mice with a targeted deletion of the SAP gene develop antinuclear Abs, which was interpreted as evidence for a role of SAP in

  14. Role of the P-Type ATPases, ATP7A and ATP7B in brain copper homeostasis

    Directory of Open Access Journals (Sweden)

    Jonathon eTelianidis

    2013-08-01

    Full Text Available Over the past two decades there have been significant advances in our understanding of copper homeostasis and the pathological consequences of copper dysregulation. Cumulative evidence is revealing a complex regulatory network of proteins and pathways that maintain copper homeostasis. The recognition of copper dysregulation as a key pathological feature in prominent neurodegenerative disorders such as Alzheimer’s, Parkinson’s and prion diseases has led to increased research focus on the mechanisms controlling copper homeostasis in the brain. The copper-transporting P-Type ATPases (copper-ATPases, ATP7A and ATP7B, are critical components of the copper regulatory network. Our understanding of the biochemistry and cell biology of these complex proteins has grown significantly since their discovery in 1993. They are large polytopic transmembrane proteins with six copper-binding motifs within the cytoplasmic N-terminal domain, eight transmembrane domains and highly conserved catalytic domains. These proteins catalyze ATP-dependent copper transport across cell membranes for the metallation of many essential cuproenzymes, as well as for the removal of excess cellular copper to prevent copper toxicity. A key functional aspect of these copper transporters is their copper-responsive trafficking between the trans-Golgi network and the cell periphery. ATP7A- and ATP7B-deficiency, due to genetic mutation, underlie the inherited copper transport disorders, Menkes and Wilson diseases, respectively. Their importance in maintaining brain copper homeostasis is underscored by the severe neuropathological deficits in these disorders. Herein we will review and update our current knowledge of these copper transporters in the brain and the central nervous system, their distribution and regulation, their role in normal brain copper homeostasis and how their absence or dysfunction contributes to disturbances in copper homeostasis and neurodegeneration.

  15. A new ternary copper(II) complex derived from 2-(2'-pyridyl)benzimidazole and glycylglycine: synthesis, characterization, DNA binding and cleavage, antioxidation and HSA interaction.

    Science.gov (United States)

    Fu, Xia-Bing; Lin, Zi-Hua; Liu, Hai-Feng; Le, Xue-Yi

    2014-03-25

    A new ternary copper(II)-dipeptide complex [Cu(glygly)(HPB)(Cl)]⋅2H2O (glygly=glycylglycine anion, HPB=2-(2'-pyridyl)benzimidazole) has been synthesized and characterized. The DNA interaction of the complex was studied by spectroscopic methods, viscosity, and electrophoresis measurements. The antioxidant activity was also investigated using the pyrogallol autoxidation assay. Besides, the interaction of the complex with human serum albumin (HSA) in vitro was examined by multispectroscopic techniques. The complex partially intercalated to CT-DNA with a high binding constant (Kb=7.28×10(5) M(-1)), and cleaved pBR322 DNA efficiently via an oxidative mechanism in the presence of Vc, with the HO· and O2(-) as the active species, and the SOD as a promoter. Furthermore, the complex shows a considerable SOD-like activity with the IC50 value of 3.8386 μM. The complex exhibits desired binding affinity to HSA, in which hydrogen bond or vander Waals force played a major role. The alterations of HSA secondary structure induced by the complex were confirmed by UV-visible, CD, synchronous fluorescence and 3D fluorescence spectroscopy. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. A new ternary copper(II) complex derived from 2-(2";-pyridyl)benzimidazole and glycylglycine: Synthesis, characterization, DNA binding and cleavage, antioxidation and HSA interaction

    Science.gov (United States)

    Fu, Xia-Bing; Lin, Zi-Hua; Liu, Hai-Feng; Le, Xue-Yi

    2014-03-01

    A new ternary copper(II)-dipeptide complex [Cu(glygly)(HPB)(Cl)]ṡ2H2O (glygly = glycylglycine anion, HPB = 2-(2";-pyridyl)benzimidazole) has been synthesized and characterized. The DNA interaction of the complex was studied by spectroscopic methods, viscosity, and electrophoresis measurements. The antioxidant activity was also investigated using the pyrogallol autoxidation assay. Besides, the interaction of the complex with human serum albumin (HSA) in vitro was examined by multispectroscopic techniques. The complex partially intercalated to CT-DNA with a high binding constant (Kb = 7.28 × 105 M-1), and cleaved pBR322 DNA efficiently via an oxidative mechanism in the presence of Vc, with the HO· and O2-rad as the active species, and the SOD as a promoter. Furthermore, the complex shows a considerable SOD-like activity with the IC50 value of 3.8386 μM. The complex exhibits desired binding affinity to HSA, in which hydrogen bond or vander Waals force played a major role. The alterations of HSA secondary structure induced by the complex were confirmed by UV-visible, CD, synchronous fluorescence and 3D fluorescence spectroscopy.

  17. Flow rate and interference studies for copper binding to a silica-immobilized humin polymer matrix: column and batch experiments.

    Science.gov (United States)

    Gardea-Torresdey, Jorge L; Contreras, Carolina; de la Rosa, Guadalupe; Peralta-Videa, Jose R

    2005-01-01

    Batch and column experiments were performed to determine the Cu(II) binding capacity of silica-immobilized humin biomass. For column studies, 500 bed volumes of a 0.1 mM Cu(II) solution were passed through humin packed columns at the flow rates of 1, 1.5, 2, and 3 mL/min. The biopolymer showed an average Cu binding capacity of 12 +/- 1.5 mg/g and a Cu recovery of about 96.5 % +/- 1.5. The breakthrough points for Cu(II) alone were approximately 420, 390, 385, and 300 bed volumes for the flow rates of 1, 1.5, 2 and 3 mL/min, respectively. The interference studies demonstrated that at low concentrations, the hard cations Ca(II) and Mg(II) did not seem to represent a major interference on Cu(II) binding to the humin biopolymer. The selectivity showed by this biopolymer was Cu(II)>Ca(II)>Mg(II). On the other hand, batch experiments showed that Ca(II) + Mg(II) at 100mM each reduced the Cu(II) binding to 73 %. However, 1000 mM concentrations of Ca(II) and Mg(II), separately and in mixture, reduced the Cu(II) binding to 47 %, 44 % and 31 %, respectively. The results of this study showed that immobilized humin in a silica matrix could represent an inexpensive bio-source for Cu removal from contaminated water, even in the presence of low concentrations of the hard cations Ca(II) and Mg(II).

  18. Synthesis, DNA binding, cellular DNA lesion and cytotoxicity of a series of new benzimidazole-based Schiff base copper(II) complexes.

    Science.gov (United States)

    Paul, Anup; Anbu, Sellamuthu; Sharma, Gunjan; Kuznetsov, Maxim L; Koch, Biplob; Guedes da Silva, M Fátima C; Pombeiro, Armando J L

    2015-12-14

    A series of new benzimidazole containing compounds 2-((1-R-1-H-benzimidazol-2-yl)phenyl-imino)naphthol HL(1-3) (R = methyl, ethyl or propyl, respectively) have been synthesized by Schiff base condensation of 2-(1-R-1-H-benzo[d]imidazol-2-yl)aniline and 2-hydroxy-1-naphthaldehyde. The reactions of HL(1-3) with Cu(NO3)2·2.5H2O led to the corresponding copper(II) complexes [Cu(L)(NO3)] 1-3. All the compounds were characterized by conventional analytical techniques and, for 1 and 3, also by single-crystal X-ray analysis. The interactions of complexes 1-3 with calf thymus DNA were studied by absorption and fluorescence spectroscopic techniques and the calculated binding constants (K(b)) are in the range of 3.5 × 10(5) M(-1)-3.2 × 10(5) M(-1). Complexes 1-3 effectively bind DNA through an intercalative mode, as proved by molecular docking studies. The binding affinity of the complexes decreases with the size increase of the N-alkyl substituent, in the order of 1 > 2 > 3, which is also in accord with the calculated LUMO(complex) energies. They show substantial in vitro cytotoxic effect against human lung (A-549), breast (MDA-MB-231) and cervical (HeLa) cancer cell lines. Complex 1 exhibits a significant inhibitory effect on the proliferation of the A-549 cancer cells. The antiproliferative efficacy of 1 has also been analysed by a DNA fragmentation assay, fluorescence activated cell sorting (FACS) and nuclear morphology using a fluorescence microscope. The possible mode for the apoptosis pathway of 1 has also been evaluated by a reactive oxygen species (ROS) generation study.

  19. DNA binding, DNA cleavage and cytotoxicity studies of a new water soluble copper(II) complex: the effect of ligand shape on the mode of binding.

    Science.gov (United States)

    Kashanian, Soheila; Khodaei, Mohammad Mehdi; Roshanfekr, Hamideh; Shahabadi, Nahid; Mansouri, Ghobad

    2012-02-01

    The interaction of native calf thymus DNA (CT-DNA) with [Cu(ph(2)phen)(phen-dione)Cl]Cl was studied at physiological pH by spectrophotometric, spectrofluorometric, circular dichroism, and viscometric techniques. Considerable hypochromicity and red shift are observed in the UV absorption band of the Cu complex. Binding constants (K(b)) of DNA with the complex were calculated at different temperatures. Thermodynamic parameters, enthalpy and entropy changes were calculated according to Van't Hoff equation, which indicated that reaction is predominantly enthalpically driven. All these results indicate that Cu(II) complex interacts with CT-DNA via intercalative mode. Also, this new complex induced cleavage in pUC18 plasmid DNA as indicated in gel electrophoresis and showed excellent antitumor activity against K562 (human chronic myeloid leukemia) and human T lymphocyte carcinoma-Jurkat cell lines. Copyright © 2011 Elsevier B.V. All rights reserved.

  20. Assessment of a spent fuel disposal canister. Assessment studies for a copper canister with cast steel inner component

    International Nuclear Information System (INIS)

    Bond, A.E.; Hoch, A.R.; Jones, G.D.; Tomczyk, A.J.; Wiggin, R.M.; Worraker, W.J.

    1997-05-01

    The proposed design for a final repository for spent fuel and other long-lived residues in Sweden, is based on the multi-barrier principle. The waste will be encapsulated in sealed cylindrical canisters, which will then be placed in vertical storage holes drilled in a series of caverns excavated from the granite bedrock at a depth of about 500 m. Each canister will be surrounded by compacted bentonite clay. In this report, a simple model of the behaviour of the canister subsequent to a first breach in its copper overpack is developed. This model is used to predict: -the ingress of water to the canister (as a function of the size and the shape of the initial defect, the buffer conductivity, the corrosion rate and the pressure inside the canister); -the build-up of corrosion products in the canister (as a function of the available water in the canister, the corrosion rate and the properties of the corrosion products); -the effect of corrosion on the structural integrity of the canister. A number of different scenarios for the location of the breach in the copper overpack are considered

  1. Spectroscopic and molecular modeling based approaches to study on the binding behavior of DNA with a copper (II) complex.

    Science.gov (United States)

    Vahdati Rad, Fatemeh; Housaindokht, Mohammad Reza; Jalal, Razieh; Eshtiagh Hosseini, Hossein; Verdian Doghaei, Asma; Sadeghi Goghari, Sadegh

    2014-07-01

    Blocking the division of tumor cells by small-molecules is currently of great interest for the design of new antitumor drugs. The interaction of a new metal complex with DNA was investigated through several techniques. Absorption spectroscopy and gel electrophoresis studies on the interaction of the Cu-complex of (2a-4mpyH)2 [Cu(pyzdc)2 (H2O)2].6 H2O with DNA have shown that this complex can bind to CT-DNA with binding constant 3.99 × 10(5) M(-1). The cyclic voltammetry (CV) responses of the metal complex in the presence of CT-DNA have shown that the metal complex can bind to CT-DNA through partial intercalation mode and this is consistent with molecular docking analysis, quenching process and thermal denaturation experiments. The cytotoxicity of this complex has been evaluated by MTT assay. The results of cell viability assay on DU145 cell line revealed that the metal complex had cytotoxic effects.

  2. Interaction between Plectranthus barbatus herbal tea components and acetylcholinesterase: binding and activity studies.

    Science.gov (United States)

    Falé, Pedro L V; Ascensão, Lia; Serralheiro, M Luisa; Haris, Parvez I

    2012-11-01

    Plectranthus barbatus water extracts, have been used as herbal teas, for the treatment of various diseases. In a previous study it was demonstrated that antioxidant and anti-acetylcholinesterase active extract constituents and their metabolites were found in the plasma of rats after P. barbatus tea intraperitoneal administration. Consequently, a decrease in brain acetylcholinesterase activity occurred. The aim of the present research is to elucidate how P. barbatus extract components interact with acetylcholinesterase. The estimated thermodynamic parameters suggest that the main intermolecular interaction is hydrophobic association, although hydrogen bonds between flavonoids and the active gorge of the acetylcholinesterase molecule seem to occur and have a great impact on acetylcholinesterase inhibition. The hydroxyl positions in flavonoids seem to be of utmost importance for enzyme inhibition, as they interact with specific amino acid residues in the active gorge. FTIR analysis showed that the plant extract components do not interfere with the secondary structure of the enzyme, but decreases the rate of hydrogen-deuterium exchange, possibly by decreasing solvent accessibility in the acetylcholinesterase active gorge. The spectroscopic data complements docking studies of acetylcholinesterase inhibition by plant phenolic compounds, clarifying the dominant interactions between enzyme and inhibitor and the most important structural features of the inhibitor molecules.

  3. Analysis of organic colouring and binding components in colour layer of art works.

    Science.gov (United States)

    Kuckova, S; Nemec, I; Hynek, R; Hradilova, J; Grygar, T

    2005-05-01

    Two methods of analysis of organic components of colour layers of art works have been tested: IR microspectroscopy of indigo, Cu-phthalocyanine, and Prussian blue, and MALDI-TOF-MS of proteinaceous binders and a protein-containing red dye. The IR spectra distortion common for smooth outer surfaces and polished cross sections of colour layer of art works is suppressed by reflectance measurement of microtome slices. The detection limit of the three blue pigments examined is approximately 0.3 wt% in reference colour layers in linseed oil binder with calcite as extender and lead white as a drying agent. The sensitivity has been sufficient to identify Prussian blue in repaints on a Gothic painting. MALDI-TOF-MS has been used to identify proteinaceous binders in two historical paintings, namely isinglass (fish glue) and rabbit glue. MALDI-TOF-MS has also been proposed for identification of an insect red dye, cochineal carmine, according to its specific protein component. The enzymatic cleavage with trypsin before MALDI-TOF-MS seems to be a very gentle and specific way of dissolution of the colour layers highly polymerised due to very long aging of old, e.g. medieval, samples.

  4. Proteomic analysis of host brain components that bind to infectious particles in Creutzfeldt-Jakob disease.

    Science.gov (United States)

    Kipkorir, Terry; Colangelo, Christopher M; Manuelidis, Laura

    2015-09-01

    Transmissible encephalopathies (TSEs), such as Creutzfeldt-Jakob disease (CJD) and scrapie, are caused by infectious agents that provoke strain-specific patterns of disease. Misfolded host prion protein (PrP-res amyloid) is believed to be the causal infectious agent. However, particles that are stripped of PrP retain both high infectivity and viral proteins not detectable in uninfected mouse controls. We here detail host proteins bound with FU-CJD agent infectious brain particles by proteomic analysis. More than 98 proteins were differentially regulated, and 56 FU-CJD exclusive proteins were revealed after PrP, GFAP, C1q, ApoE, and other late pathologic response proteins were removed. Stripped FU-CJD particles revealed HSC70 (144× the uninfected control), cyclophilin B, an FU-CJD exclusive protein required by many viruses, and early endosome-membrane pathways known to facilitate viral processing, replication, and spread. Synaptosomal elements including synapsin-2 (at 33×) and AP180 (a major FU-CJD exclusive protein) paralleled the known ultrastructural location of 25 nm virus-like TSE particles and infectivity in synapses. Proteins without apparent viral or neurodegenerative links (copine-3), and others involved in viral-induced protein misfolding and aggregation, were also identified. Human sCJD brain particles contained 146 exclusive proteins, and heat shock, synaptic, and viral pathways were again prominent, in addition to Alzheimer, Parkinson, and Huntington aggregation proteins. Host proteins that bind TSE infectious particles can prevent host immune recognition and contribute to prolonged cross-species transmissions (the species barrier). Our infectious particle strategy, which reduces background sequences by >99%, emphasizes host targets for new therapeutic initiatives. Such therapies can simultaneously subvert common pathways of neurodegeneration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Identification of pheromone components and their binding affinity to the odorant binding protein CcapOBP83a-2 of the Mediterranean fruit fly, Ceratitis capitata

    Czech Academy of Sciences Publication Activity Database

    Siciliano, P.; He, X. L.; Woodcock, C.; Pickett, J. A.; Field, L. M.; Birkett, M. A.; Kalinová, Blanka; Gomulski, L. M.; Scolari, F.; Gasperi, G.; Malacrida, A. R.; Zhou, J. J.

    2014-01-01

    Roč. 48, May (2014), s. 51-62 ISSN 0965-1748 Institutional support: RVO:61388963 Keywords : medfly * Ceratitis capitata * olfaction * odorant binding protein * pheromone binding protein * pheromone * binding studies * protein expression * electroantennography * GC-EAG * fluorescence displacement Subject RIV: CE - Biochemistry Impact factor: 3.450, year: 2014

  6. Cytotoxic activity, albumin and DNA binding of new copper(II) complexes with chalcone-derived thiosemicarbazones.

    Science.gov (United States)

    Da Silva, Jeferson G; Recio Despaigne, Angel A; Louro, Sonia R W; Bandeira, Cristiano C; Souza-Fagundes, Elaine M; Beraldo, Heloisa

    2013-07-01

    [Cu(HL)Cl2] complexes of chalcone-derived thiosemicarbazones were obtained with 3-phenyl-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCTPh), complex (1), 3-(4-chlorophenyl)-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4ClPh), complex (2), 3-(4-bromophenyl)-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4BrPh), complex (3), and 3-(4-nitrophenyl-1-pyridin-2-ylprop-2-en-1-one thiosemicarbazone (HPyCT4NO2Ph), complex (4). 1-3 showed interaction with bovine serum albumin (BSA) and deoxyribonucleic acid from calf thymus (CT-DNA). The cytotoxic activities of the thiosemicarbazones and complexes (1-4) were tested against HL60 (wild type human promyelocytic leukemia), Jurkat (human immortalized line of T lymphocyte), MDA-MB 231 (human breast carcinoma) and HCT-116 (human colorectal carcinoma) tumor cell lineages. Upon coordination to copper(II) cytotoxicity significantly increased in Jurkat, MDA-MB 231 and HCT-116 cells. Unlike the free thiosemicarbazones, 1-4 induced DNA fragmentation in solid tumor cells indicating their pro-apoptotic potential. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  7. Advanced purification strategy for CueR, a cysteine containing copper(I) and DNA binding protein.

    Science.gov (United States)

    Balogh, Ria K; Gyurcsik, Béla; Hunyadi-Gulyás, Éva; Christensen, Hans E M; Jancsó, Attila

    2016-07-01

    Metal ion regulation is essential for living organisms. In prokaryotes metal ion dependent transcriptional factors, the so-called metalloregulatory proteins play a fundamental role in controlling the concentration of metal ions. These proteins recognize metal ions with an outstanding selectivity. A detailed understanding of their function may be exploited in potential health, environmental and analytical applications. Members of the MerR protein family sense a broad range of mostly late transition and heavy metal ions through their cysteine thiolates. The air sensitivity of latter groups makes the expression and purification of such proteins challenging. Here we describe a method for the purification of the copper-regulatory CueR protein under optimized conditions. In order to avoid protein precipitation and/or eventual aggregation and to get rid of the co-purifying Escherichia coli elongation factor, our procedure consisted of four steps supplemented by DNA digestion. Subsequent anion exchange on Sepharose FF Q 16/10, affinity chromatography on Heparin FF 16/10, second anion exchange on Source 30 Q 16/13 and gel filtration on Superdex 75 26/60 resulted in large amounts of pure CueR protein without any affinity tag. Structure and functionality tests performed with mass spectrometry, circular dichroism spectroscopy and electrophoretic gel mobility shift assays approved the success of the purification procedure. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Development of bonding techniques between tungsten and copper alloy for plasma facing components by HIP method (2). Bonding between tungsten and DS-copper

    International Nuclear Information System (INIS)

    Saito, Shigeru; Fukaya, Kiyoshi; Eto, Motokuni; Ishiyama, Shintaro; Akiba, Masato

    2000-02-01

    Recently, W (tungsten)-alloys are considered as plasma facing material (PFM) for ITER because of these many favorable properties such as high melting point (3655 K), relatively high thermal conductivity and higher resistivity for plasma sputtering. On the other hand, Cu-alloys, especially DS (dispersion strengthened)-Cu, are proposed as heat sink materials because of its high thermal conductivity and good mechanical properties at high temperature. Plasma facing components (PFC) are designed as the duplex structure where W armor tiles are bonded with Cu-alloy heat sink. Then, we started the bonding technology development by hot isostatic press (HIP) method to bond W with Cu-alloys because of its many advantages. Until now, it was reported that we could get the best HIP bonding conditions for W and OFHC-Cu and the tensile strength was similar with HIP treated OFHC-Cu. In this experiments, bonding tests of W and DS-Cu with insert material were performed. As insert material, OFHC-Cu was used with different thickness. Bonding conditions were selected as 1273 K x 2 hours x 147 MPa. Bonding tests with 0.3 to 1.8 mm thickness OFHC-Cu were successfully bonded but with 0.1 mm thickness was not bonded. From the results of tensile tests, the tensile strength of the specimens with 0.3 and 0.5 mm thickness were decreased at elevated temperature. It was shown that over 1.0 mm thickness OFHC-Cu insert may be needed and the tensile strength were a little higher than that of HIP treated OFHC-Cu. (author)

  9. Binding selectivity of vitamin K3 based chemosensors towards nickel(II) and copper(II) metal ions

    Science.gov (United States)

    Patil, Amit; Lande, Dipali N.; Nalkar, Archana; Gejji, Shridhar P.; Chakrovorty, Debamitra; Gonnade, Rajesh; Moniz, Tânia; Rangel, Maria; Pereira, Eulália; Salunke-Gawali, Sunita

    2017-09-01

    The vitamin K3 derivatives 2-methyl-3-[(pyridin-2-ylmethyl)-amino]-1,4-naphthoquinone (M-1), 2-methyl-3-[(pyridin-2-ylethyl)-amino]-1,4-naphthoquinone (M-2), 2-methyl-3-((2-(thiophen-2-yl)methyl)amino)naphthalene-1,4-dione (M-3) and 2-methyl-3-((2-(thiophen-2-yl)ethyl)amino)naphthalene-1,4-dione (M-4) have been synthesized, characterized and studied for their chemosensor abilities towards transition metal ions. Crystal structures of M-1 to M-4 revealed a variety of Nsbnd H⋯O, Csbnd H⋯O, Csbnd H⋯π and π⋯π interactions. Minor variations in such interactions by chemical stimuli such as metal ions, results in change in color that can be visualized by naked eyes. It has been shown that electronic structure and 1H NMR, vibrational as well as electronic spectra from the density functional theory agree well with the experiments. The metal ion binding in ethanol, ethanol-water and in mild base triethylamine brings forth recognizing ability of M-1 toward Ni2+ whereas M-2 exhibits large sensing ability for Cu2+ ion. Interestingly M-1 display varying metal ion binding specificity in different solvents with the association constant in ethanol being 11,786 M-1 for Ni2+ compared to 9462 M-1 for the Cu2+. A reversal in preferential binding of M-2 with the respective association constants being 4190 M-1 and 6370 M-1 is discernible.

  10. The Sigma-2 Receptor and Progesterone Receptor Membrane Component 1 are Different Binding Sites Derived From Independent Genes

    Directory of Open Access Journals (Sweden)

    Uyen B. Chu

    2015-11-01

    Full Text Available The sigma-2 receptor (S2R is a potential therapeutic target for cancer and neuronal diseases. However, the identity of the S2R has remained a matter of debate. Historically, the S2R has been defined as (1 a binding site with high affinity to 1,3-di-o-tolylguanidine (DTG and haloperidol but not to the selective sigma-1 receptor ligand (+-pentazocine, and (2 a protein of 18–21 kDa, as shown by specific photolabeling with [3H]-Azido-DTG and [125I]-iodoazido-fenpropimorph ([125I]-IAF. Recently, the progesterone receptor membrane component 1 (PGRMC1, a 25 kDa protein, was reported to be the S2R (Nature Communications, 2011, 2:380. To confirm this identification, we created PGRMC1 knockout NSC34 cell lines using the CRISPR/Cas9 technology. We found that in NSC34 cells devoid of or overexpressing PGRMC1, the maximum [3H]-DTG binding to the S2R (Bmax as well as the DTG-protectable [125I]-IAF photolabeling of the S2R were similar to those of wild-type control cells. Furthermore, the affinities of DTG and haloperidol for PGRMC1 (KI = 472 μM and 350 μM, respectively, as determined in competition with [3H]-progesterone, were more than 3 orders of magnitude lower than those reported for the S2R (20–80 nM. These results clarify that PGRMC1 and the S2R are distinct binding sites expressed by different genes.

  11. Identification of components of the streptomycin-binding center of E. coli MRE 600 ribosomes by photo-affinity labelling.

    Science.gov (United States)

    Girshovich, A S; Bochkareva, E S; Ovchinnikov, Y A

    1976-03-22

    The [H3]-labelled photo-activated analog of streptomycin (photo-Sm) is obtained as a result of the streptomycin reaction with 2-nitro, 4-azidobenzoylhydrazide and subsequent reduction with NaBH34. The analog retains the functional activity of the initial antibiotic as judged by two criteria: (1) it binds only to the 30S subparticle of ribosomes and (2) it inhibits the factor-free ("non-enzymatic") PCMB-stimulated polyU-dependent system of translation (Gavrilova and Spirin, 1971). After irradiation of the reaction mixture containing photo-Sm and either the 30S or 50S subparticles of ribosomes under similar conditions, the analog covalently binds chiefly to the 30S subparticle. Irradiation of the photo-Sm mixture with whole 70S ribosomes leads to a uniform distribution of a covalently bound label among the subparticles. A comparison of the effects obtained allows the conclusion that the analog is located on the interface of the ribosomal subparticles. In the 30S subparticle the photo-Sm attacks mainly the protein component (more than 95% of all the covalently bound label). The proteins labelled by photo-reaction are identified as S7 (main), S14 (additional) and S16/S17 (minor).

  12. Genome-wide DNA binding pattern of two-component system response regulator RhpR in Pseudomonas syringae

    Directory of Open Access Journals (Sweden)

    Tianhong Zhou

    2015-06-01

    Full Text Available Although Pseudomonas syringae uses the two-component system RhpRS to modulate the expression of type III secretion system (T3SS genes and pathogenicity, the molecular mechanisms and the regulon of RhpRS have yet to be fully demonstrated. We have performed a genome-wide analysis of RhpR binding to DNA prepared from P. syringae pv. phaseolicola in order to identify candidate direct targets of RhpR-mediated transcriptional regulation, as described in our recent article [1]. The data are available from NCBI Gene Expression Omnibus (GEO with the accession number GSE58533. Here we describe the detailed methods and data analyses of our RhpR ChIP-seq dataset.

  13. Application of tungsten-fibre-reinforced copper matrix composites to a high-heat-flux component: A design study by dual scale finite element analysis

    International Nuclear Information System (INIS)

    Jeong-Ha You

    2006-01-01

    According to the European Power Plant Conceptual Study, actively cooled tungsten mono-block is one of the divertor design options for fusion reactors. In this study the coolant tube acts as a heat sink and the tungsten block as plasma-facing armour. A key material issue here is how to achieve high temperature strength and high heat conductivity of the heat sink tube simultaneously. Copper matrix composite reinforced with continuous strong fibres has been considered as a candidate material for heat sink of high-heat-flux components. Refractory tungsten wire is a promising reinforcement material due to its high strength, winding flexibility and good interfacial wetting with copper. We studied the applicability of tungsten-fibre-reinforced copper matrix composite heat sink tubes for the tungsten mono-block divertor by means of dual-scale finite element analysis. Thermo-elasto-plastic micro-mechanics homogenisation technique was applied. A heat flux of 15 MW/m 2 with cooling water temperature of 320 o C was considered. Effective stress-free temperature was assumed to be 500 o C. Between the tungsten block and the composite heat sink tube interlayer (1 mm thick) of soft Cu was inserted. The finite element analysis yields the following results: The predicted maximum temperature at steady state is 1223 o C at the surface and 562 o C at the interface between tube and copper layer. On the macroscopic scale, residual stress is generated during fabrication due to differences in thermal expansion coefficients of the materials. Strong compressive stress occurs in the tungsten block around the tube while weak tensile stress is present in the interlayer. The local and global probability of brittle failure of the tungsten block was also estimated using the probabilistic failure theories. The thermal stresses are significantly decreased upon subsequent heat flux loading. Resolving the composite stress on microscopic scale yields a maximum fibre axial stress of 3000 MPa after

  14. Influence of water chemistry and dissolved organic matter (DOM) molecular size on copper and mercury binding determined by multiresponse fluorescence quenching.

    Science.gov (United States)

    Chen, W B; Smith, D S; Guéguen, C

    2013-07-01

    The effects of water chemistry (i.e. pH and Ca(2+) concentration) dissolved organic carbon (DOC) concentration) and DOM quality (i.e. composition and molecular weight) on metal complexation were successfully investigated by a combination of tangential flow filtration, excitation-emission matrix fluorescence, parallel factor analysis (PARAFAC), and fluorescence quenching on four freshwater samples and one extracted Suwannee River fulvic acid (SRFA). Two terrestrial and one microbial humic-like components were found in this study. Despite strong correlation between the Ryan-Weber model and the multiresponse model, the latter is more appropriate for the calculation of binding parameters in multiple-ligand DOM system. Decreasing pH from 6 to 4 significantly reduced logK-Cu(2+) from 5.22±0.24 to 4.60±0.30 at pH 6 and 4, respectively (pHigh molecular weight (>1kDa) DOM generally had higher logK and binding fluorophore abundance than bulk (unfractionated) and low molecular weight (<1kDa) DOM for both metals. This trend however was not always true for Hg(2+) where the binding parameters were quite variable. Overall the combined results provide evidence that binding parameters are not only affected by water chemistry, but also depend on DOM molecular weight. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Copper complexes based on chiral Schiff-base ligands: DNA/BSA binding ability, DNA cleavage activity, cytotoxicity and mechanism of apoptosis.

    Science.gov (United States)

    Zhou, Xue-Quan; Li, Yang; Zhang, Dong-Yan; Nie, Yan; Li, Zong-Jin; Gu, Wen; Liu, Xin; Tian, Jin-Lei; Yan, Shi-Ping

    2016-05-23

    Four copper(II) complexes with chiral Schiff-base ligands, [Cu(R-L(1))2]·EtOAc (1) and [Cu(S-L(1))2]·EtOAc (2), [Cu(R-L(2))2]·EtOAc (3) and [Cu(S-L(2))2]·EtOAc (4), (R/S-HL(1) = (R/S)-(1-naththyl)-salicylaldimine, R/S-HL(2) = (R/S)-(1-naththyl)-3-methoxysalicylaldimine, EtOAc = ethyl acetate) were synthesized to serve as artificial nucleases and anticancer drugs. All complexes and R/S-HL(1) ligands were structurally characterized by X-ray crystallography. The interaction of these complexes with CT-DNA was researched via several spectroscopy methods, which indicates that complexes bind to CT-DNA by moderate intercalation binding mode. Moreover, DNA cleavage experiments revealed that the complexes exhibited remarkable DNA cleavage activities in the presence of H2O2via the generation of hydroxyl radical. Particularly, complex 4 also could nick DNA with the production of (1)O2. And all complexes exhibited excellent cytotoxicity to MDA-MB-231, A549 and Hela human cancer cells in micromole magnitude. Furthermore, complex 4 exhibited comparable cytotoxic effect to cisplatin against the proliferation of MDA-MB-231 and A549 cancer cells, as well as showed better anticancer ability to the three cancer cells than the other complexes. The results of cell cycle analysis indicated that complexes 3-4 could induce G2/M phase cell cycle arrest. Furthermore, MDA-MB-231 cells treated with 3 and 4 were subjected to apoptosis and death by generation of ROS and the activation of caspase-3. Interestingly, the chiral complexes 3 and 4 may induce cell apoptosis through extrinsic and mitochondrial intrinsic pathway, respectively. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  16. Parameterizing the binding properties of dissolved organic matter with default values skews the prediction of copper solution speciation and ecotoxicity in soil.

    Science.gov (United States)

    Djae, Tanalou; Bravin, Matthieu N; Garnier, Cédric; Doelsch, Emmanuel

    2017-04-01

    Parameterizing speciation models by setting the percentage of dissolved organic matter (DOM) that is reactive (% r-DOM) toward metal cations at a single 65% default value is very common in predictive ecotoxicology. The authors tested this practice by comparing the free copper activity (pCu 2+  = -log 10 [Cu 2+ ]) measured in 55 soil sample solutions with pCu 2+ predicted with the Windermere humic aqueous model (WHAM) parameterized by default. Predictions of Cu toxicity to soil organisms based on measured or predicted pCu 2+ were also compared. Default WHAM parameterization substantially skewed the prediction of measured pCu 2+ by up to 2.7 pCu 2+ units (root mean square residual = 0.75-1.3) and subsequently the prediction of Cu toxicity for microbial functions, invertebrates, and plants by up to 36%, 45%, and 59% (root mean square residuals ≤9 %, 11%, and 17%), respectively. Reparametrizing WHAM by optimizing the 2 DOM binding properties (i.e., % r-DOM and the Cu complexation constant) within a physically realistic value range much improved the prediction of measured pCu 2+ (root mean square residual = 0.14-0.25). Accordingly, this WHAM parameterization successfully predicted Cu toxicity for microbial functions, invertebrates, and plants (root mean square residual ≤3.4%, 4.4%, and 5.8%, respectively). Thus, it is essential to account for the real heterogeneity in DOM binding properties for relatively accurate prediction of Cu speciation in soil solution and Cu toxic effects on soil organisms. Environ Toxicol Chem 2017;36:898-905. © 2016 SETAC. © 2016 SETAC.

  17. Effects of copper and cadmium on ion transport and gill metal binding in the Amazonian teleost tambaqui (Colossoma macropomum) in extremely soft water.

    Science.gov (United States)

    Matsuo, Aline Y O; Wood, Chris M; Val, Adalberto L

    2005-09-30

    Metal toxicity in fish is expected to be most severe in soft waters because of the low availability of cations (particularly Ca(2+)) to out-compete the metal forms for binding sites on the gills. Natural waters in the Amazon basin are typically soft due to regional geochemistry, but few studies have focused on metal toxicity in fish native to the basin. We assessed the ionoregulatory effects of waterborne copper (Cu) and cadmium (Cd) on tambaqui (Colossoma macropomum) in extremely soft water (10 micromoll(-1) Ca(2+)). Tambaqui had a very high tolerance to Cu (50-400 microgl(-1)), as indicated by a complete lack of inhibition of Na(+) uptake and an ability to gradually recover over 6h from elevated diffusive Na(+) losses caused by Cu. The insensitivity of active Na(+) influx to Cu further supports the notion that Amazonian fish may have a unique Na(+) transport system. Addition of 5-10 mgCl(-1) of dissolved organic matter (DOM) did not prevent initial (0-3h) negative Na(+) balance in tambaqui exposed to Cu. Exposure to 40 mgCl(-1) DOM prevented Na(+) losses in tambaqui even at 400 microgl(-1) Cu, probably because most Cu was complexed to DOM. Tambaqui exposed to waterborne Cd (10-80 microgl(-1)) experienced an average of 42% inhibition in whole body Ca(2+) uptake relative to controls within 3h of exposure to the metal. Inhibition of Ca(2+) uptake increased over time and, at 24h, Ca(2+) uptake was suppressed by 51% and 91% in fish exposed to 10 and 80 microgl(-1) Cd, respectively. Previous acclimation of fish to either elevated [Ca(2+)] or elevated [DOM] proved to be very effective in protecting against acute short-term metal accumulation at the gills of tambaqui in soft water (in the absence of the protective agent during metal exposure), suggesting a conditioning effect on gill metal binding physiology.

  18. Templated synthesis of copper(II) azacyclam complexes using urea as a locking fragment and their metal-enhanced binding tendencies towards anions.

    Science.gov (United States)

    Boiocchi, Massimo; Fabbrizzi, Luigi; Garolfi, Mauro; Licchelli, Maurizio; Mosca, Lorenzo; Zanini, Cristina

    2009-10-26

    Copper(II) azacyclam complexes 3(2+) and 4(2+) were obtained through a metal-templated procedure involving the pertinent open-chain tetramine, formaldehyde and a phenylurea derivative as a locking fragment. Both metal complexes can establish interactions with anions through the metal centre and the amide NH group. Equilibrium studies in DMSO by a spectrophotometric titration technique were carried out to assess the affinity of 3(2+) and 4(2+) towards anions. While the NH group of an amide model compound and the metal centre of the plain Cu(II)(azacyclam)(2+) complex do not interact at all with anions, 3(2+) and 4(2+) establish strong interactions with oxo anions, profiting from a pronounced cooperative effect. In particular, 1) they form stable 1:1 and 1:2 complexes with H(2)PO(4) (-) ions in a stepwise mode with both hydrogen-bonding and metal-ligand interactions, and 2) in the presence of CH(3)COO(-), they undergo deprotonation of the amido NH group and thus profit from axial coordination of the partially negatively charged carbonyl oxygen atom in a scorpionate binding mode.

  19. The study of marine corrosion of copper alloys in chlorinated condenser cooling circuits: the role of microbiological components.

    Science.gov (United States)

    Carvalho, Maria L; Doma, Jemimah; Sztyler, Magdalena; Beech, Iwona; Cristiani, Pierangela

    2014-06-01

    The present paper reports the on-line monitoring of corrosion behavior of the CuNi 70:30 and Al brass alloys exposed to seawater and complementary offline microbiological analyses. An electrochemical equipment with sensors specifically set for industrial application and suitable to estimate the corrosion (by linear polarization resistance technique), the biofilm growth (by the BIOX electrochemical probe), the chlorination treatment and other physical-chemical parameters of the water has been used for the on-line monitoring. In order to identify and better characterize the bacteria community present on copper alloys, tube samples were collected after a long period (1year) and short period (2days) of exposition to treated natural seawater (TNSW) and natural seawater (NSW). From the collected samples, molecular techniques such as DNA extraction, polymerase chain reaction (PCR), denaturing gradient gel electrophoresis (DGGE) and identification by sequencing were performed to better characterize and identify the microbial biodiversity present in the samples. The monitoring data confirmed the significant role played by biofouling deposition against the passivity of these Cu alloys in seawater and the positive influence of antifouling treatments based on low level dosages. Molecular analysis indicated biodiversity with the presence of Marinobacter, Alteromonas and Pseudomonas species. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Evaluation of Immobilized Metal-Ion Affinity Chromatography and Electrospray Ionization Tandem Mass Spectrometry for Recovery and Identification of Copper(II)-Binding Ligands in Seawater Using the Model Ligand 8-Hydroxyquinoline

    OpenAIRE

    Nixon, Richard L.; Ross, Andrew R. S.

    2016-01-01

    Complexation by organic ligands dominates the speciation of iron (Fe), copper (Cu), and other bioactive trace metals in seawater, controlling their bioavailability and distribution in the marine environment. Several classes of high-affinity Fe-binding ligands (siderophores) have been identified in seawater but the chemical structures of marine Cu-complexing ligands remain unknown. Immobilized metal-ion affinity chromatography (IMAC) allows Cu ligands to be isolated from bulk dissolved organic...

  1. The adenovirus E4 11 k protein binds and relocalizes the cytoplasmic P-body component Ddx6 to aggresomes

    International Nuclear Information System (INIS)

    Greer, Amy E.; Hearing, Patrick; Ketner, Gary

    2011-01-01

    The adenovirus E4 11 k protein, product of E4 ORF3, is required in infection for processes including normal accumulation of viral late mRNAs. 11 k restructures both the nucleus and cytoplasm of infected cells by relocalizing specific host cell target proteins, most strikingly components of nuclear PML oncogenic domains. It is likely that in many cases relocalization inactivates target proteins to produce 11 k's effects, although the mechanism and targets for stimulation of late mRNA accumulation is unknown. We have identified a new set of proteins relocalized by 11 k: at least five protein components of cytoplasmic mRNA processing bodies (p-bodies) are found in 11 k-induced cytoplasmic aggresomes, sites where proteins are inactivated or destroyed. One of these p-body proteins, RNA helicase Ddx6, binds 11 k, suggesting a mechanism for relocalization. Because p-bodies are sites for mRNA degradation, their modification by 11 k may provide an explanation for the role of 11 k in viral late mRNA accumulation.

  2. Residues essential for Panton-Valentine leukocidin S component binding to its cell receptor suggest both plasticity and adaptability in its interaction surface.

    Directory of Open Access Journals (Sweden)

    Benoit-Joseph Laventie

    Full Text Available Panton-Valentine leukocidin (PVL, a bicomponent staphylococcal leukotoxin, is involved in the poor prognosis of necrotizing pneumonia. The present study aimed to elucidate the binding mechanism of PVL and in particular its cell-binding domain. The class S component of PVL, LukS-PV, is known to ensure cell targeting and exhibits the highest affinity for the neutrophil membrane (Kd∼10(-10 M compared to the class F component of PVL, LukF-PV (Kd∼10(-9 M. Alanine scanning mutagenesis was used to identify the residues involved in LukS-PV binding to the neutrophil surface. Nineteen single alanine mutations were performed in the rim domain previously described as implicated in cell membrane interactions. Positions were chosen in order to replace polar or exposed charged residues and according to conservation between leukotoxin class S components. Characterization studies enabled to identify a cluster of residues essential for LukS-PV binding, localized on two loops of the rim domain. The mutations R73A, Y184A, T244A, H245A and Y250A led to dramatically reduced binding affinities for both human leukocytes and undifferentiated U937 cells expressing the C5a receptor. The three-dimensional structure of five of the mutants was determined using X-ray crystallography. Structure analysis identified residues Y184 and Y250 as crucial in providing structural flexibility in the receptor-binding domain of LukS-PV.

  3. Nanocrystalline copper(II oxide-catalyzed one-pot four- component synthesis of polyhydroquinoline derivativesunder solvent-free conditions

    Directory of Open Access Journals (Sweden)

    J. Safaei-Ghomi

    2011-07-01

    Full Text Available The efficient and environmentally friendly method for the one-pot synthesis of polyhydroquinolines has been developed in the presence of CuO nanoparticles. The multi-component reactions of aldehydes, dimedone, ethyl acetoacetate andammonium acetate were carried out under solvent-free conditions to afford some polyhydroquinoline derivatives. This method provides several advantages including high yields, low reaction times and little catalyst loading.

  4. Binding of complement proteins C1q and C4bp to serum amyloid P component (SAP) in solid contra liquid phase

    DEFF Research Database (Denmark)

    Sørensen, Inge Juul; Nielsen, EH; Andersen, Ove

    1996-01-01

    Serum amyloid P component (SAP), a member of the conserved pentraxin family of plasma proteins, binds calcium dependently to its ligands. The authors investigated SAPs interaction with the complement proteins C4b binding protein (C4bp) and C1q by ELISA, immunoelectrophoresis and electron microscopy....... Binding of these proteins to SAP was demonstrated when SAP was immobilized using F(ab')2 anti-SAP, but not when SAP reacted with these proteins in liquid phase; thus the binding to human SAP was markedly phase state dependent. Presaturation of solid phase SAP with heparin, which binds SAP with high...... affinity, did not interfere with the subsequent binding of C4bp or C1q to SAP. In contrast, collagen I and IV showed partial competition with the binding of C1q to SAP. Using fresh serum, immobilized native SAP bound C4bp whereas binding of C1q/C1 could not be demonstrated. Altogether the results indicate...

  5. Five water-soluble zwitterionic copper(II)-carboxylate polymers: role of dipyridyl coligands in enhancing the DNA-binding, cleaving and anticancer activities.

    Science.gov (United States)

    Chen, Ming; Tang, Xiao-Yan; Yang, Shui-Ping; Li, Huan-Huan; Zhao, Hai-Qing; Jiang, Zhi-Hong; Chen, Jin-Xiang; Chen, Wen-Hua

    2015-08-07

    Five water-soluble zwitterionic copper-carboxylate polymers were prepared from the reaction of N-carboxymethyl-(3,5-dicarboxyl)pyridinium bromide (H3CmdcpBr) with Cu(NO3)2 in the presence of NaOH by modulating the temperature, solvent and ancillary dipyridyl ligands. These complexes include a 1D ladder-shaped polymer {[Cu3(Cmdcp)2(OH)2(H2O)2]·H2O}n () formed in H2O at room temperature, and a 2D network polymer {[Cu(Cmdcp) (H2O)2]·2H2O}n () isolated in H2O at 135 °C. At 100 °C in H2O/DMF, the same reaction in the presence of an additional 2,2'-bipyridine (bipy) gave a 2D zwitterionic complex {[Cu(Cmdcp)(bipy)]·3H2O}n () together with a 1D double-stranded polymer {[Cu(Cmdcp)(H2O)2]·H2O}n () as a minor product. The replacement of bipy with phenanthroline (phen) afforded a 1D zigzag polymer chain {[Cu(Cmdcp)(phen)(H2O)]2·9H2O}5 (). All these complexes were characterized by IR, elemental analyses and single crystal X-ray crystallography. Agarose gel electrophoresis (GE) and ethidium bromide (EB) displacement experiments indicated that complex exhibited the highest pBR322 DNA cleaving ability with the catalytic efficiency (kmax/KM) of 14.80 h(-1) mM(-1) and the highest binding affinity toward calf-thymus DNA. The MTT assay indicated that complex showed significant inhibitory activity toward the proliferation of several tumor cells. Its IC50 value was at micromolar level and lower than those of cisplatin and complexes , especially toward resistant lung adenocarcinoma cell A549.

  6. Biosorption of chromium, copper and zinc by wine-processing waste sludge: Single and multi-component system study

    International Nuclear Information System (INIS)

    Liu, Cheng-Chung; Wang, Ming-Kuang; Chiou, Chyow-San; Li, Yuan-Shen; Yang, Chia-Yi; Lin, Yu-An

    2009-01-01

    Wine-processing waste sludge (WPWS) has been shown to have powerful potential for sorption of some heavy metals (i.e., chromium, lead and nickel) in single-component aqueous solutions. But although most industrial wastewater contains two or more toxic metals, there are few sorption studies on multicomponent metals by WPWS. This study has two goals: (i) conduct competitive adsorption using Cr, Cu and Zn as sorbates and examine their interaction in binary or ternary systems; and (ii) determine the effects of temperature on the kinetic sorption reaction. The sludge tested contained a high amount of organic matter (38%) and had a high cation exchange capacity (CEC, 255 cmol c kg -1 ). Infrared analysis reveals that carboxyl is the main functional group in this WPWS. The 13 C NMR determination indicates alkyl-C and carboxyl-C are major organic functional groups. At steady state, there are about 40.4% (Cr), 35.0% (Cu) and 21.9% (Zn) sorbed in the initial 6.12 mM of single-component solutions. Only pseudo-second-order sorption kinetic model successfully describes the kinetics of sorption for all experimental metals. The rate constants, k 2 , of Cr, Cu and Zn in single-component solutions are 0.016, 0.030 and 0.154 g mg -1 min -1 , respectively. The sorption of metals by WPWS in this competitive system shows the trend: Cr > Cu > Zn. Ions of charge, hydrated radius and electronic configuration are main factors affecting sorption capacity. The least sorption for Zn in this competitive system can be attributed to its full orbital and largest hydrated radius. Though the effect of temperature on Zn sorption is insignificant, high temperature favors the other metallic sorptions, in particular for Cr. However, the Cr sorption is lower than Cu at 10 deg. C. The Cr sorption by WPWS can be higher than that of Cu at 30 deg. and 50 deg. C.

  7. In Vitro DNA-Binding, Anti-Oxidant and Anticancer Activity of Indole-2-Carboxylic Acid Dinuclear Copper(II Complexes

    Directory of Open Access Journals (Sweden)

    Xiangcong Wang

    2017-01-01

    Full Text Available Indole-2-carboxylic acid copper complex (ICA-Cu was successfully prepared and characterized through elemental analysis, IR, UV-Vis, 1H-NMR, TG analysis, and molar conductance, and its molecular formula was [Cu2(C9H6O2N4(H2O2]·2H2O. The binding ability of ICA-Cu to calf thymus DNA (CT-DNA was examined by fluorescence spectrometry and the viscosity method. The results indicated that, upon the addition of increasing amounts of CT-DNA, the excitation and emission intensity of ICA-Cu decreased obviously and the excitation spectra shifted towards a long wavelength. ICA-Cu could displace ethidium bromide (EB from the EB-DNA system, making the fluorescence intensity of the EB-DNA system decrease sharply; the quenching constant KSV value was 3.99 × 104 M−1. The emission intensity of the ICA-Cu-DNA system was nearly constant, along with the addition of Na+ in a series of concentrations. The fluorescence of the complex could be protected after the complex interacted with DNA. A viscosity measurement further supported the result that the ICA-Cu complex may interact with DNA in an intercalative binding mode. The antioxidant activities of ICA-Cu were evaluated by a 2,2-diphenyl-1-picrylhydrazyl (DPPH assay, a hydroxyl radical (OH scavenging assay, and a 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS assay. The ICA-Cu exhibited the highest inhibitory effects on the ABTS radical (94% inhibition at 60 µM, followed by OH and DPPH radicals (the degrees of inhibition being 71% and 56%, respectively. The in vitro cytotoxicity activity of ICA-Cu against two human breast cancer cell lines, MDA-MB-231 and MCF-7, was investigated by 3-[4,5-dimethyltiazol2-yl]-2.5-diphenyl-tetrazolium bromide (MTT assay and cellular morphological analysis. The results showed that, upon increasing the concentration of ICA-Cu, an increase was observed in growth-inhibitory activity and the inhibition percentage were greater than 90% at 20 µM in both cell lines. Also

  8. In Vitro DNA-Binding, Anti-Oxidant and Anticancer Activity of Indole-2-Carboxylic Acid Dinuclear Copper(II) Complexes.

    Science.gov (United States)

    Wang, Xiangcong; Yan, Maocai; Wang, Qibao; Wang, Huannan; Wang, Zhengyang; Zhao, Jiayi; Li, Jing; Zhang, Zhen

    2017-01-20

    Indole-2-carboxylic acid copper complex (ICA-Cu) was successfully prepared and characterized through elemental analysis, IR, UV-Vis, ¹H-NMR, TG analysis, and molar conductance, and its molecular formula was [Cu₂(C₉H₆O₂N)₄(H₂O)₂]·2H₂O. The binding ability of ICA-Cu to calf thymus DNA (CT-DNA) was examined by fluorescence spectrometry and the viscosity method. The results indicated that, upon the addition of increasing amounts of CT-DNA, the excitation and emission intensity of ICA-Cu decreased obviously and the excitation spectra shifted towards a long wavelength. ICA-Cu could displace ethidium bromide (EB) from the EB-DNA system, making the fluorescence intensity of the EB-DNA system decrease sharply; the quenching constant K SV value was 3.99 × 10⁴ M -1 . The emission intensity of the ICA-Cu-DNA system was nearly constant, along with the addition of Na⁺ in a series of concentrations. The fluorescence of the complex could be protected after the complex interacted with DNA. A viscosity measurement further supported the result that the ICA-Cu complex may interact with DNA in an intercalative binding mode. The antioxidant activities of ICA-Cu were evaluated by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, a hydroxyl radical (OH) scavenging assay, and a 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay. The ICA-Cu exhibited the highest inhibitory effects on the ABTS radical (94% inhibition at 60 µM), followed by OH and DPPH radicals (the degrees of inhibition being 71% and 56%, respectively). The in vitro cytotoxicity activity of ICA-Cu against two human breast cancer cell lines, MDA-MB-231 and MCF-7, was investigated by 3-[4,5-dimethyltiazol2-yl]-2.5-diphenyl-tetrazolium bromide (MTT) assay and cellular morphological analysis. The results showed that, upon increasing the concentration of ICA-Cu, an increase was observed in growth-inhibitory activity and the inhibition percentage were greater than 90% at 20 µM in both cell

  9. Effects of copper and cadmium on ion transport and gill metal binding in the Amazonian teleost tambaqui (Colossoma macropomum) in extremely soft water

    Energy Technology Data Exchange (ETDEWEB)

    Matsuo, Aline Y.O. [Laboratory of Ecophysiology and Molecular Evolution, National Institute for Research in the Amazon (INPA), Av. Andre Araujo, 2936 Aleixo, Manaus, Amazonas 69083-000 (Brazil)]. E-mail: matsuoaline@aol.com; Wood, Chris M. [Department of Biology, McMaster University, 1280 Main St. West, Hamilton, Ont., L8S 4K1 (Canada); Val, Adalberto L. [Laboratory of Ecophysiology and Molecular Evolution, National Institute for Research in the Amazon (INPA), Av. Andre Araujo, 2936 Aleixo, Manaus, Amazonas 69083-000 (Brazil)

    2005-09-30

    Metal toxicity in fish is expected to be most severe in soft waters because of the low availability of cations (particularly Ca{sup 2+}) to out-compete the metal forms for binding sites on the gills. Natural waters in the Amazon basin are typically soft due to regional geochemistry, but few studies have focused on metal toxicity in fish native to the basin. We assessed the ionoregulatory effects of waterborne copper (Cu) and cadmium (Cd) on tambaqui (Colossoma macropomum) in extremely soft water (10 {mu}mol l{sup -1} Ca{sup 2+}). Tambaqui had a very high tolerance to Cu (50-400 {mu}g l{sup -1}), as indicated by a complete lack of inhibition of Na{sup +} uptake and an ability to gradually recover over 6 h from elevated diffusive Na{sup +} losses caused by Cu. The insensitivity of active Na{sup +} influx to Cu further supports the notion that Amazonian fish may have a unique Na{sup +} transport system. Addition of 5-10 mg C l{sup -1} of dissolved organic matter (DOM) did not prevent initial (0-3 h) negative Na{sup +} balance in tambaqui exposed to Cu. Exposure to 40 mg C l{sup -1} DOM prevented Na{sup +} losses in tambaqui even at 400 {mu}g l{sup -1} Cu, probably because most Cu was complexed to DOM. Tambaqui exposed to waterborne Cd (10-80 {mu}g l{sup -1}) experienced an average of 42% inhibition in whole body Ca{sup 2+} uptake relative to controls within 3 h of exposure to the metal. Inhibition of Ca{sup 2+} uptake increased over time and, at 24 h, Ca{sup 2+} uptake was suppressed by 51% and 91% in fish exposed to 10 and 80 {mu}g l{sup -1} Cd, respectively. Previous acclimation of fish to either elevated [Ca{sup 2+}] or elevated [DOM] proved to be very effective in protecting against acute short-term metal accumulation at the gills of tambaqui in soft water (in the absence of the protective agent during metal exposure), suggesting a conditioning effect on gill metal binding physiology.

  10. Borrelia burgdorferi outer surface protein C (OspC) binds complement component C4b and confers bloodstream survival.

    Science.gov (United States)

    Caine, Jennifer A; Lin, Yi-Pin; Kessler, Julie R; Sato, Hiromi; Leong, John M; Coburn, Jenifer

    2017-12-01

    Borrelia burgdorferi (Bb) is the causative agent of Lyme disease in the United States, a disease that can result in carditis, and chronic and debilitating arthritis and/or neurologic symptoms if left untreated. Bb survives in the midgut of the Ixodes scapularis tick, or within tissues of immunocompetent hosts. In the early stages of infection, the bacteria are present in the bloodstream where they must resist clearance by the innate immune system of the host. We have found a novel role for outer surface protein C (OspC) from B. burgdorferi and B. garinii in interactions with the complement component C4b and bloodstream survival in vivo. Our data show that OspC inhibits the classical and lectin complement pathways and competes with complement protein C2 for C4b binding. Resistance to complement is important for maintenance of the lifecycle of Bb, enabling survival of the pathogen within the host as well as in the midgut of a feeding tick when ospC expression is induced. © 2017 John Wiley & Sons Ltd.

  11. COPT6 is a plasma membrane transporter that functions in copper homeostasis in Arabidopsis and is a novel target of SQUAMOSA promoter binding protein-like 7

    Science.gov (United States)

    Among the mechanisms controlling copper homeostasis in plants is the regulation of its uptake and tissue partitioning. Here we characterized a newly identified member of the conserved CTR/COPT family of copper transporters in Arabidopsis thaliana, COPT6. We showed that COPT6 resides at the plasma me...

  12. Oxygen binding and activation by the complexes of PY2- and TPA-appended diphenylglycoluril receptors with copper and other metals

    NARCIS (Netherlands)

    Sprakel, VSI; Feiters, MC; Klaucke, WM; Klopstra, M; Brinksma, J; Feringa, BL; Karlin, KD; Nolte, RJM; Sprakel, Vera S.I.; Feiters, Martin C.; Meyer-Klaucke, Wolfram; Karlin, Kenneth D.; Nolte, Roeland J.M.; Feringa, Bernard

    2005-01-01

    The copper( I) complexes of diphenylglycoluril basket receptors 1 and 2, appended with bis(2-ethylpyridine) amine (PY2) and tris(2-methylpyridine) amine (TPA), respectively, and their dioxygen adducts were studied with low-temperature UV-vis and X-ray absorption spectroscopy (XAS). The copper(I)

  13. Binding Selectivity of Methanobactin from Methylosinus trichosporium OB3b for Copper(I), Silver(I), Zinc(II), Nickel(II), Cobalt(II), Manganese(II), Lead(II), and Iron(II)

    Science.gov (United States)

    McCabe, Jacob W.; Vangala, Rajpal; Angel, Laurence A.

    2017-12-01

    Methanobactin (Mb) from Methylosinus trichosporium OB3b is a member of a class of metal binding peptides identified in methanotrophic bacteria. Mb will selectively bind and reduce Cu(II) to Cu(I), and is thought to mediate the acquisition of the copper cofactor for the enzyme methane monooxygenase. These copper chelating properties of Mb make it potentially useful as a chelating agent for treatment of diseases where copper plays a role including Wilson's disease, cancers, and neurodegenerative diseases. Utilizing traveling wave ion mobility-mass spectrometry (TWIMS), the competition for the Mb copper binding site from Ag(I), Pb(II), Co(II), Fe(II), Mn(II), Ni(II), and Zn(II) has been determined by a series of metal ion titrations, pH titrations, and metal ion displacement titrations. The TWIMS analyses allowed for the explicit identification and quantification of all the individual Mb species present during the titrations and measured their collision cross-sections and collision-induced dissociation patterns. The results showed Ag(I) and Ni(II) could irreversibly bind to Mb and not be effectively displaced by Cu(I), whereas Ag(I) could also partially displace Cu(I) from the Mb complex. At pH ≈ 6.5, the Mb binding selectivity follows the order Ag(I)≈Cu(I)>Ni(II)≈Zn(II)>Co(II)>>Mn(II)≈Pb(II)>Fe(II), and at pH 7.5 to 10.4 the order is Ag(I)>Cu(I)>Ni(II)>Co(II)>Zn(II)>Mn(II)≈Pb(II)>Fe(II). Breakdown curves of the disulfide reduced Cu(I) and Ag(I) complexes showed a correlation existed between their relative stability and their compact folded structure indicated by their CCS. Fluorescence spectroscopy, which allowed the determination of the binding constant, compared well with the TWIMS analyses, with the exception of the Ni(II) complex. [Figure not available: see fulltext.

  14. Biosorption of chromium, copper and zinc by wine-processing waste sludge: Single and multi-component system study

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Cheng-Chung [Department of Environmental Engineering, National Ilan University, Ilan, 260, Taiwan (China); Wang, Ming-Kuang, E-mail: mkwang@ntu.edu.tw [Department of Agricultural Chemistry, National Taiwan University, Taipei, 106, Taiwan (China); Chiou, Chyow-San; Li, Yuan-Shen [Department of Environmental Engineering, National Ilan University, Ilan, 260, Taiwan (China); Yang, Chia-Yi [Department of Chemical and Materials Engineering, Tamkang University, Tamsui, 251, Taiwan (China); Lin, Yu-An [Department of Animal Science, National Ilan University, Ilan, 260, Taiwan (China)

    2009-11-15

    Wine-processing waste sludge (WPWS) has been shown to have powerful potential for sorption of some heavy metals (i.e., chromium, lead and nickel) in single-component aqueous solutions. But although most industrial wastewater contains two or more toxic metals, there are few sorption studies on multicomponent metals by WPWS. This study has two goals: (i) conduct competitive adsorption using Cr, Cu and Zn as sorbates and examine their interaction in binary or ternary systems; and (ii) determine the effects of temperature on the kinetic sorption reaction. The sludge tested contained a high amount of organic matter (38%) and had a high cation exchange capacity (CEC, 255 cmol{sub c} kg{sup -1}). Infrared analysis reveals that carboxyl is the main functional group in this WPWS. The {sup 13}C NMR determination indicates alkyl-C and carboxyl-C are major organic functional groups. At steady state, there are about 40.4% (Cr), 35.0% (Cu) and 21.9% (Zn) sorbed in the initial 6.12 mM of single-component solutions. Only pseudo-second-order sorption kinetic model successfully describes the kinetics of sorption for all experimental metals. The rate constants, k{sub 2}, of Cr, Cu and Zn in single-component solutions are 0.016, 0.030 and 0.154 g mg{sup -1} min{sup -1}, respectively. The sorption of metals by WPWS in this competitive system shows the trend: Cr > Cu > Zn. Ions of charge, hydrated radius and electronic configuration are main factors affecting sorption capacity. The least sorption for Zn in this competitive system can be attributed to its full orbital and largest hydrated radius. Though the effect of temperature on Zn sorption is insignificant, high temperature favors the other metallic sorptions, in particular for Cr. However, the Cr sorption is lower than Cu at 10 deg. C. The Cr sorption by WPWS can be higher than that of Cu at 30 deg. and 50 deg. C.

  15. In vitro cytotoxic activities, DNA-, and BSA-binding studies of a new dinuclear copper(II) complex with N-[3-(dimethylamino)propyl]-N'-(2-carboxylatophenyl)-oxamide as ligand.

    Science.gov (United States)

    Jiao, Jing; Jiang, Man; Li, Yan-Tuan; Wu, Zhi-Yong; Yan, Cui-Wei

    2014-02-01

    A new dinuclear copper(II) complex bridged by N-[3-(dimethylamino)propyl]-N'- (2-carbo-xylatophenyl)oxamide (H3 dmapob), and endcapped with 2,2'-diamino-4,4'-bithiazole (dabt), namely [Cu₂(dmapob)(dabt)(CH₃OH)(pic)]·(DMF)₀.₇₅ ·(CH₃OH)₀.₂₅ has been synthesized and characterized by elemental analysis, molar conductivity measurement, infrared and electronic spectra studies, and single-crystal X-ray diffraction. In the crystal structure, both copper(II) ions have square-pyramidal coordination geometries. The Cu···Cu separation through the oxamido bridge is 5.176(9) Å. A two-dimensional supramolecular framework is formed through hydrogen bonds and π-π stacking interactions. The reactivities toward herring sperm DNA and bovine serum albumin (BSA) show that the complex can interact with the DNA via intercalation mode and bind to the BSA responsible for quenching of tryptophan fluorescence by the static quenching mechanism. The in vitro anticancer activities suggest that the copper(II) complex is active against the selected tumor cell lines. The influence of different bridging ligands in dinuclear complexes on the DNA- and BSA-binding properties as well as anticancer activities is preliminarily discussed. © 2013 Wiley Periodicals, Inc.

  16. Purification, subunit characterization and ultrastructure of three soluble bovine lectins: conglutinin, mannose-binding protein and the pentraxin serum amyloid P-component

    DEFF Research Database (Denmark)

    Andersen, Ove; Friis, P; Holm Nielsen, E

    1992-01-01

    Conglutinin and mannose-binding protein (MBP) are members of the C-type lectins which are widely present in mammalian plasma. Serum amyloid P-component (SAP) is a member of the pentraxin family with lectin properties. A scheme for the partial purification of all three lectins by carbohydrate...... affinity chromatography and selective elution was developed. The purification was monitored by SDS-PAGE, Western blotting and electron microscopy. Binding of the lectins to Sephadex-iC3b, their collagenase sensitivity, and the size and antibody reactivity of their subunits was investigated....... The demonstration, by SDS-PAGE, of 25-kDa subunits, which were unaffected by collagenase treatment but bound to Sephadex-iC3b and antibodies to human SAP, indicated the existence of bovine SAP. Bovine conglutinin (BK) also showed calcium-dependent binding to Sephadex-iC3b, whereas bovine MBP did not. The binding...

  17. Serum amyloid P component binds to influenza A virus haemagglutinin and inhibits the virus infection in vitro

    DEFF Research Database (Denmark)

    Andersen, Ove; Vilsgaard Ravn, K; Juul Sørensen, I

    1997-01-01

    that SAP can bind to influenza A virus and inhibit agglutination of erythrocytes mediated by the virus subtypes H1N1, H2N2 and H3N2. SAP also inhibits the production of haemagglutinin (HA) an the cytopathogenic effect of influenza A virus in MDCK cells. The binding of SAP to the virus requires...

  18. Molybdate binding by ModA, the periplasmic component of the Escherichia coli mod molybdate transport system.

    Science.gov (United States)

    Imperial, J; Hadi, M; Amy, N K

    1998-03-13

    ModA, the periplasmic-binding protein of the Escherichia coli mod transport system was overexpressed and purified. Binding of molybdate and tungstate to ModA was found to modify the UV absorption and fluorescence emission spectra of the protein. Titration of these changes showed that ModA binds molybdate and tungstate in a 1:1 molar ratio. ModA showed an intrinsic fluorescence emission spectrum attributable to its three tryptophanyl residues. Molybdate binding caused a conformational change in the protein characterized by: (i) a shift of tryptophanyl groups to a more hydrophobic environment; (ii) a quenching (at pH 5.0) or enhancement (at pH 7.8) of fluorescence; and (iii) a higher availability of tryptophanyl groups to the polar quencher acrylamide. The tight binding of molybdate did not allow an accurate estimation of the binding constants by these indirect methods. An isotopic binding method with 99MoO42- was used for accurate determination of KD (20 nM) and stoichiometry (1:1 molar ratio). ModA bound tungstate with approximately the same affinity, but did not bind sulfate or phosphate. These KDs are 150- to 250-fold lower than those previously reported, and compatible with the high molybdate transport affinity of the mod system. The affinity of ModA for molybdate was also determined in vivo and found to be similar to that determined in vitro. Copyright 1998 Elsevier Science B.V.

  19. New copper resistance determinants in the extremophile acidithiobacillus ferrooxidans: a quantitative proteomic analysis.

    Science.gov (United States)

    Almárcegui, Rodrigo J; Navarro, Claudio A; Paradela, Alberto; Albar, Juan Pablo; von Bernath, Diego; Jerez, Carlos A

    2014-02-07

    Acidithiobacillus ferrooxidans is an extremophilic bacterium used in biomining processes to recover metals. The presence in A. ferrooxidans ATCC 23270 of canonical copper resistance determinants does not entirely explain the extremely high copper concentrations this microorganism is able to stand, suggesting the existence of other efficient copper resistance mechanisms. New possible copper resistance determinants were searched by using 2D-PAGE, real time PCR (qRT-PCR) and quantitative proteomics with isotope-coded protein labeling (ICPL). A total of 594 proteins were identified of which 120 had altered levels in cells grown in the presence of copper. Of this group of proteins, 76 were up-regulated and 44 down-regulated. The up-regulation of RND-type Cus systems and different RND-type efflux pumps was observed in response to copper, suggesting that these proteins may be involved in copper resistance. An overexpression of most of the genes involved in histidine synthesis and several of those annotated as encoding for cysteine production was observed in the presence of copper, suggesting a possible direct role for these metal-binding amino acids in detoxification. Furthermore, the up-regulation of putative periplasmic disulfide isomerases was also seen in the presence of copper, suggesting that they restore copper-damaged disulfide bonds to allow cell survival. Finally, the down-regulation of the major outer membrane porin and some ionic transporters was seen in A. ferrooxidans grown in the presence of copper, indicating a general decrease in the influx of the metal and other cations into the cell. Thus, A. ferrooxidans most likely uses additional copper resistance strategies in which cell envelope proteins are key components. This knowledge will not only help to understand the mechanism of copper resistance in this extreme acidophile but may help also to select the best fit members of the biomining community to attain more efficient industrial metal leaching

  20. Calcium-dependent and -independent binding of the pentraxin serum amyloid P component to glycosaminoglycans and amyloid proteins

    DEFF Research Database (Denmark)

    Danielsen, B; Sørensen, I J; Nybo, Mads

    1997-01-01

    and beta2M) by ELISA. An increase in the dose-dependent binding of SAP to heparan sulfate, AA-protein and beta2M was observed as the pH decreased from 8.0 to 5.0. Furthermore, a lower, but significant Ca2(+)-independent binding of SAP to heparan sulfate, dermatan sulfate, AA protein and the amyloid...... precursor protein beta2M was observed. This binding was also enhanced at slightly acid pH, most pronounced at pH 5.0. The results of this study indicate that SAP can exhibit both Ca2(+)-dependent and -independent binding to ligands involved in amyloid fibril formation and that the binding is enhanced under...

  1. Interaction between the Natural Components in Danhong Injection (DHI) with Serum Albumin (SA) and the Influence of the Coexisting Multi-Components on the SaB-BSA Binding System: Fluorescence and Molecular Docking Studies

    Science.gov (United States)

    Hao, Jia; Zhang, Yingyue; Wang, Xingrui; Yan, Huo; Liu, Erwei; Gao, Xiumei

    2015-01-01

    Danhong injection (DHI) is a widely used Chinese Materia Medica standardized product for the clinical treatment of ischemic encephalopathy and coronary heart disease. The bindings of eight natural components in DHI between bovine serum albumin (BSA) were studied by fluorescence spectroscopy technology and molecular docking. According to the results, the quenching process of salvianolic acid B and hydroxysafflor yellow A was a static quenching procedure through the analysis of quenching data by the Stern-Volmer equation, the modified Stern-Volmer equation, and the modified Scatchard equation. Meanwhile, syringin (Syr) enhanced the fluorescence of BSA, and the data were analyzed using the Lineweaver-Burk equation. Molecular docking suggested that all of these natural components bind to serum albumin at the site I location. Further competitive experiments of SaB confirmed the result of molecular docking studies duo to the displacement of warfarin by SaB. Base on these studies, we selected SaB as a research target because it presented the strongest binding ability to BSA and investigated the influence of the multi-components coexisting in DHI on the interaction between the components of the SaB-BSA binding system. The participation of these natural components in DHI affected the interaction between the components of the SaB-BSA system. Therefore, when DHI is used in mammals, SaB is released from serum albumin more quickly than it is used alone. This work would provide a new experiment basis for revealing the scientific principle of compatibility for Traditional Chinese Medicine. PMID:26035712

  2. Synthesis, characterization, biological activity, DNA and BSA binding study: novel copper(ii) complexes with 2-hydroxy-4-aryl-4-oxo-2-butenoate.

    Science.gov (United States)

    Joksimović, Nenad; Baskić, Dejan; Popović, Suzana; Zarić, Milan; Kosanić, Marijana; Ranković, Branislav; Stanojković, Tatjana; Novaković, Sladjana B; Davidović, Goran; Bugarčić, Zorica; Janković, Nenad

    2016-09-27

    A serie of novel square pyramidal copper(ii) complexes [Cu(L) 2 H 2 O] (3a-d) with O,O-bidentate ligands [L = ethyl-2-hydroxy-4-aryl-4-oxo-2-butenoate; aryl = 3-methoxyphenyl-2a, (E)-2-phenylvinyl-2b, (E)-2-(4'-hydroxy-3'-methoxyphenyl)vinyl-2c, 3-nitrophenyl-2d, 2-thienyl-2e] were synthesized and characterized by spectral (UV-Vis, IR, ESI-MS and EPR), elemental and X-ray analysis. The antimicrobial activity was estimated by the determination of the minimal inhibitory concentration (MIC) using the broth microdilution method. The most active antibacterial compounds were 3c and 3d, while the best antifungal activity was showed by complexes 3b and 3e. The lowest MIC value (0.048 mg mL -1 ) was measured for 3c against Proteus mirabilis. The cytotoxic activity was tested using the MTT method on human epithelial carcinoma HeLa cells, human lung carcinoma A549 cells and human colon carcinoma LS174 cells. All complexes showed extremely better cytotoxic activity compared to cisplatin at all tested concentrations. Compound 3d expressed the best activity against all tested cell lines with IC 50 values ranging from 7.45 to 7.91 μg mL -1 . The type of cell death and the impact on the cell cycle for 3d and 3e were evaluated by flow cytometry. Both compounds induced apoptosis and S phase cell cycle arrest. The interactions between selected complexes (3d and 3e) and CT-DNA or bovine serum albumin (BSA) were investigated by the fluorescence spectroscopic method. Competitive experiments with ethidium bromide (EB) indicated that 3d and 3e have a propensity to displace EB from the EB-DNA complex through intercalation suggesting strong competition with EB [K sv = (1.4 ± 0.2) and (2.9 ± 0.1) × 10 4 M -1 , respectively]. K sv values indicate that these complexes bind to DNA covalently and non-covalently. The achieved results in the fluorescence titration of BSA with 3d and 3e [K a = (2.9 ± 0.2) × 10 6 and (2.5 ± 0.2) × 10 5 M, respectively] showed that the fluorescence quenching

  3. Crystal structure of U2 snRNP SF3b components: Hsh49p in complex with Cus1p-binding domain

    Science.gov (United States)

    van Roon, Anne-Marie M.; Obayashi, Eiji; Sposito, Benedetta; Newman, Andrew J.; Séraphin, Bertrand

    2017-01-01

    Spliceosomal proteins Hsh49p and Cus1p are components of SF3b, which together with SF3a, Msl1p/Lea1p, Sm proteins, and U2 snRNA, form U2 snRNP, which plays a crucial role in pre-mRNA splicing. Hsh49p, comprising two RRMs, forms a heterodimer with Cus1p. We determined the crystal structures of Saccharomyces cerevisiae full-length Hsh49p as well as its RRM1 in complex with a minimal binding region of Cus1p (residues 290–368). The structures show that the Cus1 fragment binds to the α-helical surface of Hsh49p RRM1, opposite the four-stranded β-sheet, leaving the canonical RNA-binding surface available to bind RNA. Hsh49p binds the 5′ end region of U2 snRNA via RRM1. Its affinity is increased in complex with Cus1(290-368)p, partly because an extended RNA-binding surface forms across the protein–protein interface. The Hsh49p RRM1–Cus1(290-368)p structure fits well into cryo-EM density of the Bact spliceosome, corroborating the biological relevance of our crystal structure. PMID:28348170

  4. Synthesis and crystal structure elucidation of new copper(II)-based chemotherapeutic agent coupled with 1,2-DACH and orthovanillin: Validated by in vitro DNA/HSA binding profile and pBR322 cleavage pathway.

    Science.gov (United States)

    Zaki, Mehvash; Afzal, Mohd; Ahmad, Musheer; Tabassum, Sartaj

    2016-08-01

    New copper(II)-based complex (1) was synthesized and characterized by analytical, spectroscopic and single crystal X-ray diffraction. The in vitro binding studies of complex 1 with CT DNA and HSA have been investigated by employing biophysical techniques to examine the binding propensity of 1 towards DNA and HSA. The results showed that 1 avidly binds to CT DNA via electrostatic mode along with the hydrogen bonding interaction of NH2 and CN groups of Schiff base ligand with the base pairs of DNA helix, leads to partial unwinding and destabilization of the DNA double helix. Moreover, the CD spectral studies revealed that complex 1 binds through groove binding interaction that stabilizes the right-handed B-form of DNA. Complex 1 showed an impressive photoinduced nuclease activity generating single-strand breaks in comparison with the DNA cleavage activity in presence of visible light. The mechanistic investigation revealed the efficiency of 1 to cleave DNA strands by involving the generation of reactive oxygen species. Furthermore, the time dependent DNA cleavage activity showed that there was gradual increase in the amount of NC DNA on increasing the photoexposure time. However, the interaction of 1 and HSA showed that the change of intrinsic fluorescence intensity of HSA was induced by the microenvironment of Trp residue. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Effects of copper supplement on growth and viability of strains used as starters and adjunct cultures for Emmental cheese manufacture.

    Science.gov (United States)

    Rodríguez, L Mato; Alatossava, T

    2008-10-01

    To determine the effects of supplemented copper (Cu2+) on growth and viability of strains used as starters and adjunct cultures for Emmental cheese manufacture. Thirteen strains belonging to Lactobacillus delbrueckii, Lactobacillus helveticus, Lactobacillus rhamnosus, Streptococcus thermophilus or Propionibacterium freudenreichii species were exposed to various copper concentrations in the proper growth medium at relevant growth temperatures, and the effects of supplemented copper on bacterial growth and cell viability were determined by optical density and pH measurements, also by platings. Among the species considered, L. delbrueckii was the most copper resistant and S. thermophilus the most sensitive to copper. Anaerobic conditions increased this sensitivity significantly. There was also a considerable amount of variation in copper resistance at strain level. Copper resistance is both a species- and strain-dependent property and may reflect variability in copper-binding capacities by cell wall components among species and strains. In addition, the chemical state of copper may be involved. This study revealed that copper resistance is a highly variable property among starter and adjunct strains, and this variability should be considered when strains are selected for Emmental cheese manufacture.

  6. Copper transport.

    Science.gov (United States)

    Linder, M C; Wooten, L; Cerveza, P; Cotton, S; Shulze, R; Lomeli, N

    1998-05-01

    In adult humans, the net absorption of dietary copper is approximately 1 mg/d. Dietary copper joins some 4-5 mg of endogenous copper flowing into the gastrointestinal tract through various digestive juices. Most of this copper returns to the circulation and to the tissues (including liver) that formed them. Much lower amounts of copper flow into and out of other major parts of the body (including heart, skeletal muscle, and brain). Newly absorbed copper is transported to body tissues in two phases, borne primarily by plasma protein carriers (albumin, transcuprein, and ceruloplasmin). In the first phase, copper goes from the intestine to the liver and kidney; in the second phase, copper usually goes from the liver (and perhaps also the kidney) to other organs. Ceruloplasmin plays a role in this second phase. Alternatively, liver copper can also exit via the bile, and in a form that is less easily reabsorbed. Copper is also present in and transported by other body fluids, including those bathing the brain and central nervous system and surrounding the fetus in the amniotic sac. Ceruloplasmin is present in these fluids and may also be involved in copper transport there. The concentrations of copper and ceruloplasmin in milk vary with lactational stage. Parallel changes occur in ceruloplasmin messenger RNA expression in the mammary gland (as determined in pigs). Copper in milk ceruloplasmin appears to be particularly available for absorption, at least in rats.

  7. Synthesis and characterization of mononuclear copper(II) complex of tetradentate N2S2 donor set and the study of DNA and bovine serum albumin binding

    OpenAIRE

    Sandipan Sarkar; Biswajit Das

    2014-01-01

    One mononuclear copper(II) complex, containing neutral tetradentate NSSN-type ligands, of formulation [Cu II(L 1)Cl]ClO 4 (1), was synthesized and isolated in pure form [where L 1˭ 1,3-bis(3-pyridylmethylthio)propane]. Green-colored copper(II) complex was characterized by physicochemical, spectroscopic methods and conductivity measurement. These experimental data matched well with the proposed structure of the complex. Biological activity of the complex (1) toward calf thymus DNA and bovine s...

  8. Degradation of the starch components amylopectin and amylose by barley α-amylase 1: Role of surface binding site 2

    DEFF Research Database (Denmark)

    Nielsen, Jonas Willum; Kramhøft, Birte; Bozonnet, Sophie

    2012-01-01

    Barley α-amylase isozyme 1 (AMY1, EC 3.2.1.1) contains two surface binding sites, SBS1 and SBS2, involved in the degradation of starch granules. The distinct role of SBS1 and SBS2 remains to be fully understood. Mutational analysis of Tyr-380 situated at SBS2 previously revealed that Tyr-380...... is required for binding of the amylose helix mimic, β-cyclodextrin. Also, mutant enzymes altered at position 380 displayed reduced binding to starch granules. Similarly, binding of wild type AMY1 to starch granules was suppressed in the presence of β-cyclodextrin. We investigated the role of SBS2 by comparing...... kinetic properties of the wild type AMY1 and the Y380A mutant enzyme in hydrolysis of amylopectin, amylose and β-limit dextrin, and the inhibition by β-cyclodextrin. Progress curves of the release of reducing ends revealed a bi-exponential hydrolysis of amylopectin and β-limit dextrin, whereas hydrolysis...

  9. Effect of the nitrogen status on copper accumulation and pools of metal-binding peptides in the planktonic diatom Thalassiosira pseudonana

    NARCIS (Netherlands)

    Rijstenbil, J.W.; Dehairs, F.; Ehrlich, R.; Wijnholds, J.A.

    1998-01-01

    Effects of the algal cellular nitrogen status on the defence against copper toxicity were studied in batch cultures of the coastal diatom Thalassiosira pseudonana, grown in coastal seawater (Oosterschelde, SW Netherlands; 30 parts per thousand salinity). The media represented nutrient-poor (summer)

  10. The effect of macromolecular crowding on the electrostatic component of barnase-barstar binding: a computational, implicit solvent-based study.

    Directory of Open Access Journals (Sweden)

    Helena W Qi

    Full Text Available Macromolecular crowding within the cell can impact both protein folding and binding. Earlier models of cellular crowding focused on the excluded volume, entropic effect of crowding agents, which generally favors compact protein states. Recently, other effects of crowding have been explored, including enthalpically-related crowder-protein interactions and changes in solvation properties. In this work, we explore the effects of macromolecular crowding on the electrostatic desolvation and solvent-screened interaction components of protein-protein binding. Our simple model enables us to focus exclusively on the electrostatic effects of water depletion on protein binding due to crowding, providing us with the ability to systematically analyze and quantify these potentially intuitive effects. We use the barnase-barstar complex as a model system and randomly placed, uncharged spheres within implicit solvent to model crowding in an aqueous environment. On average, we find that the desolvation free energy penalties incurred by partners upon binding are lowered in a crowded environment and solvent-screened interactions are amplified. At a constant crowder density (fraction of total available volume occupied by crowders, this effect generally increases as the radius of model crowders decreases, but the strength and nature of this trend can depend on the water probe radius used to generate the molecular surface in the continuum model. In general, there is huge variation in desolvation penalties as a function of the random crowder positions. Results with explicit model crowders can be qualitatively similar to those using a lowered "effective" solvent dielectric to account for crowding, although the "best" effective dielectric constant will likely depend on multiple system properties. Taken together, this work systematically demonstrates, quantifies, and analyzes qualitative intuition-based insights into the effects of water depletion due to crowding on the

  11. Evaluation of the sensitization rates and identification of IgE-binding components in wild and genetically modified potatoes in patients with allergic disorders

    Directory of Open Access Journals (Sweden)

    Kim Seung-Hyun

    2006-07-01

    Full Text Available Abstract Background The potato is one of the most common types of genetically modified (GM food. However, there are no published data evaluating the impact of genetic manipulations on the allergenicity of GM potatoes. To compare the allergenicity of GM potatoes with that of wild-type potatoes using in vivo and in vitro methods in adult allergy patients sensitized to potatoes. Methods A total of 1886 patients with various allergic diseases and 38 healthy controls participated in the study. Skin-prick testing and IgE-ELISA were carried out with extracts prepared from wild-type and GM potatoes. An ELISA inhibition test was used to confirm the binding specificity. IgE-binding components in extracts from the two types of potato were identified by SDS-PAGE and IgE-immunoblotting. The effects of digestive enzymes and heat on the allergenicity of the extracts was evaluated by preincubating the potatoes with or without simulated gastric and intestinal fluids in the absence or presence of heat. Results Positive responses (ratio of the wheal size induced by the allergen to that induced by histamine (A/H ≥ 2+ to wild-type or GM potato extracts, as demonstrated by the skin-prick test, were observed in 108 patients (5.7%. Serum-specific IgE was detected in 0–88% of subjects who tested positively. ELISA inhibition tests indicated significant inhibition when extract from each type of potato was added. IgE-immunoblot analysis demonstrated the presence of 14 IgE-binding components within the wild-type potato and 9 within the GM potato. Furthermore, a common 45-kDa binding component that yielded similar IgE-binding patterns was noted in more than 80% of the reactions using sera from patients sensitized to wild-type or GM potato. Exposure to simulated gastric fluid and heat treatment similarly inhibited IgE binding by extracts from wild-type and GM potatoes, whereas minimal changes were obtained following exposure of the extracts to simulated intestinal fluid

  12. Analysis of Heme Iron Coordination in DGCR8: The Heme-Binding Component of the Microprocessor Complex.

    Science.gov (United States)

    Girvan, Hazel M; Bradley, Justin M; Cheesman, Myles R; Kincaid, James R; Liu, Yilin; Czarnecki, Kazimierz; Fisher, Karl; Leys, David; Rigby, Stephen E J; Munro, Andrew W

    2016-09-13

    DGCR8 is the RNA-binding partner of the nuclease Drosha. Their complex (the "Microprocessor") is essential for processing of long, primary microRNAs (pri-miRNAs) in the nucleus. Binding of heme to DGCR8 is essential for pri-miRNA processing. On the basis of the split Soret ultraviolet-visible (UV-vis) spectrum of ferric DGCR8, bis-thiolate sulfur (cysteinate, Cys(-)) heme iron coordination of DGCR8 heme iron was proposed. We have characterized DGCR8 heme ligation using the Δ276 DGCR8 variant and combined electron paramagnetic resonance (EPR), magnetic circular dichroism (MCD), electron nuclear double resonance, resonance Raman, and electronic absorption spectroscopy. These studies indicate DGCR8 bis-Cys heme iron ligation, with conversion from bis-thiolate (Cys(-)/Cys(-)) axial coordination in ferric DGCR8 to bis-thiol (CysH/CysH) coordination in ferrous DGCR8. Pri-miRNA binding does not perturb ferric DGCR8's optical spectrum, consistent with the axial ligand environment being separated from the substrate-binding site. UV-vis absorption spectra of the Fe(II) and Fe(II)-CO forms indicate discrete species exhibiting peaks with absorption coefficients substantially larger than those for ferric DGCR8 and that previously reported for a ferrous form of DGCR8. Electron-nuclear double resonance spectroscopy data exclude histidine or water as axial ligands for ferric DGCR8 and favor bis-thiolate coordination in this form. UV-vis MCD and near-infrared MCD provide data consistent with this conclusion. UV-vis MCD data for ferrous DGCR8 reveal features consistent with bis-thiol heme iron coordination, and resonance Raman data for the ferrous-CO form are consistent with a thiol ligand trans to the CO. These studies support retention of DGCR8 cysteine coordination upon reduction, a conclusion distinct from those of previous studies of a different ferrous DGCR8 isoform.

  13. Identification of Escherichia coli ZapC (YcbW) as a component of the division apparatus that binds and bundles FtsZ polymers.

    Science.gov (United States)

    Hale, Cynthia A; Shiomi, Daisuke; Liu, Bing; Bernhardt, Thomas G; Margolin, William; Niki, Hironori; de Boer, Piet A J

    2011-03-01

    Assembly of the cell division apparatus in bacteria starts with formation of the Z ring on the cytoplasmic face of the membrane. This process involves the accumulation of FtsZ polymers at midcell and their interaction with several FtsZ-binding proteins that collectively organize the polymers into a membrane-associated ring-like configuration. Three such proteins, FtsA, ZipA, and ZapA, have previously been identified in Escherichia coli. FtsA and ZipA are essential membrane-associated division proteins that help connect FtsZ polymers with the inner membrane. ZapA is a cytoplasmic protein that is not required for the fission process per se but contributes to its efficiency, likely by promoting lateral interactions between FtsZ protofilaments. We report the identification of YcbW (ZapC) as a fourth FtsZ-binding component of the Z ring in E. coli. Binding of ZapC promotes lateral interactions between FtsZ polymers and suppresses FtsZ GTPase activity. This and additional evidence indicate that, like ZapA, ZapC is a nonessential Z-ring component that contributes to the efficiency of the division process by stabilizing the polymeric form of FtsZ.

  14. H-binding of size- and polarity-fractionated soil and lignite humic acids after removal of metal and ash components

    Science.gov (United States)

    Drosos, Marios; Leenheer, Jerry A.; Avgeropoulos, Apostolos; Deligiannakis, Yiannis

    2014-01-01

    A fractionation technique, combining dialysis removal of metal and ash components with hydrofluoric acid and pH 10 citrate buffer followed by chromatography of dialysis permeate on XAD-8 resin at decreasing pH values, has been applied to lignite humic acid (lignite-HA) and soil humic acid (soil-HA). H-binding data and non ideal competitive adsorption-Donnan model parameters were obtained for the HA fractions by theoretical analysis of H-binding data which reveal a significant increase of the carboxyl and the phenolic charge for the lignite-HA fractions vs. the parental lignite humic acid (LParentalHA). The fractionated lignite-HA material consisted mainly of permeate fractions, some of which were fulvic acid-like. The fractionated soil-HA material consisted mainly of large macromolecular structures that did not permeate the dialysis membrane during deashing. Chargeable groups had comparable concentrations in soil-HA fractions and parental soil humic acid (SParentalHA), indicating minimal interference of ash components with carboxyl and phenolic (and/or enolic) groups. Fractionation of HA, combined with theoretical analysis of H-binding, can distinguish the supramolecular vs. macromolecular nature of fractions within the same parental HA.

  15. Binding of Streptococcus pneumoniae Endopeptidase O (PepO) to Complement Component C1q Modulates the Complement Attack and Promotes Host Cell Adherence*

    Science.gov (United States)

    Agarwal, Vaibhav; Sroka, Magdalena; Fulde, Marcus; Bergmann, Simone; Riesbeck, Kristian; Blom, Anna M.

    2014-01-01

    The Gram-positive species Streptococcus pneumoniae is a human pathogen causing severe local and life-threatening invasive diseases associated with high mortality rates and death. We demonstrated recently that pneumococcal endopeptidase O (PepO) is a ubiquitously expressed, multifunctional plasminogen and fibronectin-binding protein facilitating host cell invasion and evasion of innate immunity. In this study, we found that PepO interacts directly with the complement C1q protein, thereby attenuating the classical complement pathway and facilitating pneumococcal complement escape. PepO binds both free C1q and C1 complex in a dose-dependent manner based on ionic interactions. Our results indicate that recombinant PepO specifically inhibits the classical pathway of complement activation in both hemolytic and complement deposition assays. This inhibition is due to direct interaction of PepO with C1q, leading to a strong activation of the classical complement pathway, and results in consumption of complement components. In addition, PepO binds the classical complement pathway inhibitor C4BP, thereby regulating downstream complement activation. Importantly, pneumococcal surface-exposed PepO-C1q interaction mediates bacterial adherence to host epithelial cells. Taken together, PepO facilitates C1q-mediated bacterial adherence, whereas its localized release consumes complement as a result of its activation following binding of C1q, thus representing an additional mechanism of human complement escape by this versatile pathogen. PMID:24739385

  16. The Arabidopsis GAGA-Binding Factor BASIC PENTACYSTEINE6 Recruits the POLYCOMB-REPRESSIVE COMPLEX1 Component LIKE HETEROCHROMATIN PROTEIN1 to GAGA DNA Motifs.

    Science.gov (United States)

    Hecker, Andreas; Brand, Luise H; Peter, Sébastien; Simoncello, Nathalie; Kilian, Joachim; Harter, Klaus; Gaudin, Valérie; Wanke, Dierk

    2015-07-01

    Polycomb-repressive complexes (PRCs) play key roles in development by repressing a large number of genes involved in various functions. Much, however, remains to be discovered about PRC-silencing mechanisms as well as their targeting to specific genomic regions. Besides other mechanisms, GAGA-binding factors in animals can guide PRC members in a sequence-specific manner to Polycomb-responsive DNA elements. Here, we show that the Arabidopsis (Arabidopsis thaliana) GAGA-motif binding factor protein basic pentacysteine6 (BPC6) interacts with like heterochromatin protein1 (LHP1), a PRC1 component, and associates with vernalization2 (VRN2), a PRC2 component, in vivo. By using a modified DNA-protein interaction enzyme-linked immunosorbant assay, we could show that BPC6 was required and sufficient to recruit LHP1 to GAGA motif-containing DNA probes in vitro. We also found that LHP1 interacts with VRN2 and, therefore, can function as a possible scaffold between BPC6 and VRN2. The lhp1-4 bpc4 bpc6 triple mutant displayed a pleiotropic phenotype, extreme dwarfism and early flowering, which disclosed synergistic functions of LHP1 and group II plant BPC members. Transcriptome analyses supported this synergy and suggested a possible function in the concerted repression of homeotic genes, probably through histone H3 lysine-27 trimethylation. Hence, our findings suggest striking similarities between animal and plant GAGA-binding factors in the recruitment of PRC1 and PRC2 components to Polycomb-responsive DNA element-like GAGA motifs, which must have evolved through convergent evolution. © 2015 American Society of Plant Biologists. All Rights Reserved.

  17. Synthesis and crystal structure of copper (II) uracil ternary polymeric complex with 1,10-phenanthroline along with the Hirshfeld surface analysis of the metal binding sites for the uracil ligand

    Science.gov (United States)

    Patil, Yogesh Prakash; Nethaji, Munirathinam

    2015-02-01

    The study of models for "metal-enzyme-substrate" interaction has been a proactive area of research owing to its biological and pharmacological importance. In this regard the ternary copper uracil complex with 1,10-phenanthroline represents metal-enzyme-substrate system for DNA binding enzymes. The synthesis of the complex, followed by slow evaporation of the reaction mixture forms two concomitant solvatomorph crystals viz., {[Cu(phen)(μ-ura)(H2O)]n·H2O (1a)} and {[Cu(phen)(μ-ura)(H2O)]n·CH3OH (1b)}. Both complexes are structurally characterized, while elemental analysis, IR and EPR spectra were recorded for 1b (major product). In both complexes, uracil coordinates uniquely via N1 and N3 nitrogen atom acting as a bidentate bridging ligand forming a 1-D polymer. The two solvatomorphs were quantitatively analyzed for the differences with the aid of Hirshfeld surface analysis.

  18. Deleted in Malignant Brain Tumors 1 is up-regulated in bacterial endocarditis and binds to components of vegetations

    DEFF Research Database (Denmark)

    Müller, Hanna; Renner, Marcus; Helmke, Burkhard M

    2009-01-01

    . The glycoprotein Deleted in Malignant Brain Tumors 1 is a scavenger receptor cysteine-rich protein with functions in innate immunity and epithelial differentiation. Because of the aggregating capacity of Deleted in Malignant Brain Tumors 1, we hypothesized that an up-regulation in bacterial endocarditis may...... be linked to the development of vegetations. METHODS: Heart tissue of 19 patients with bacterial endocarditis and 10 controls without bacterial endocarditis was analyzed by immunohistochemistry. The effect of human recombinant Deleted in Malignant Brain Tumors 1 on erythrocyte aggregation was measured using...... an automated red blood cell aggregometer MA1. Binding of human recombinant Deleted in Malignant Brain Tumors 1 to erythrocyte membranes, platelets, fibrin, and fibrinogen was analyzed by Western blotting and enzyme-linked immunosorbent assay. RESULTS: Deleted in Malignant Brain Tumors 1 expression was up...

  19. Copper hypersensitivity

    DEFF Research Database (Denmark)

    Fage, Simon W; Faurschou, Annesofie; Thyssen, Jacob P

    2014-01-01

    . As a metal, it possesses many of the same qualities as nickel, which is a known strong sensitizer. Cumulative data on subjects with presumed related symptoms and/or suspected exposure showed that a weighted average of 3.8% had a positive patch test reaction to copper. We conclude that copper is a very weak...... hypersensitivity, a database search of PubMed was performed with the following terms: copper, dermatitis, allergic contact dermatitis, contact hypersensitivity, contact sensitization, contact allergy, patch test, dental, IUD, epidemiology, clinical, and experimental. Human exposure to copper is relatively common...

  20. Copper wire bonding

    CERN Document Server

    Chauhan, Preeti S; Zhong, ZhaoWei; Pecht, Michael G

    2014-01-01

    This critical volume provides an in-depth presentation of copper wire bonding technologies, processes and equipment, along with the economic benefits and risks.  Due to the increasing cost of materials used to make electronic components, the electronics industry has been rapidly moving from high cost gold to significantly lower cost copper as a wire bonding material.  However, copper wire bonding has several process and reliability concerns due to its material properties.  Copper Wire Bonding book lays out the challenges involved in replacing gold with copper as a wire bond material, and includes the bonding process changes—bond force, electric flame off, current and ultrasonic energy optimization, and bonding tools and equipment changes for first and second bond formation.  In addition, the bond–pad metallurgies and the use of bare and palladium-coated copper wires on aluminum are presented, and gold, nickel and palladium surface finishes are discussed.  The book also discusses best practices and re...

  1. A copper(I)-catalyzed three-component domino process: assembly of complex 1,2,3-triazolyl-5-phosphonates from azides, alkynes, and H-phosphates.

    Science.gov (United States)

    Li, Lingjun; Hao, Guoliang; Zhu, Anlian; Fan, Xincui; Zhang, Guisheng; Zhang, Lihe

    2013-10-18

    Three is better than one! A new copper-catalyzed tricomponent reaction of a terminal alkyne, organic azide, and H-phosphate (CuAA[P]C) leads to a structurally diverse polysubstituted 1,2,3-triazolyl-5-phosphonate, which provides an efficient tool for the direct introduction of phosphonic acid groups by a "click reaction". Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Synthesis, structure information, DNA/BSA binding affinity and in vitro cytotoxic studies of mixed ligand copper(II) complexes containing a phenylalanine derivative and diimine co-ligands.

    Science.gov (United States)

    Annaraj, B; Balakrishnan, C; Neelakantan, M A

    2016-07-01

    Binary [Cu(PAIC)(H2O)2]·H2O (1) and mixed ligand [Cu(PAIC)(L)]·2H2O complexes, where PAIC=phenylalanine imidazole carboxylic acid, L=diimine coligands [2,2'-bipyridine (bpy) (2) and 1,10-phenanthroline (phen) (3)] have been synthesized and fully characterized by analytical and spectral techniques. The X-ray structure of [Cu(PAIC)(phen)]·2H2O (3) shows a N4O coordination with square pyramidal geometry around the copper (II) atom. The spin Hamiltonian parameters calculated for the complexes account for the distorted square planar structure and rules out the possibility of a trigonal bipyramidal structure. Interaction of the complexes (1-3) with calf thymus DNA (CT DNA) was studied by using different techniques (absorption titration, fluorescence quenching and thermal melting) and the studies suggest that these complexes bind to CT DNA through intercalation. The DNA-binding affinity of the complexes has further been explained by DFT computational results. Binding activity of Bovine serum albumin (BSA) reveals that the complexes can strongly quench the intrinsic fluorescence of BSA through a static quenching mechanism. DNA cleavage experiments using plasmid DNA pUC 19 show that the complexes exhibit efficient chemical nuclease activity even in the absence of any external additives. The cytotoxicity of the complexes against human normal cell line (HBL 100) and human breast cancer cell line (MCF-7) shows that metal complexation of the ligands results in a significant enhancement in the cell death of MCF-7. Finally, docking studies on DNA and protein binding interactions were performed. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Control of flowering and cell fate by LIF2, an RNA binding partner of the polycomb complex component LHP1.

    Directory of Open Access Journals (Sweden)

    David Latrasse

    Full Text Available Polycomb Repressive Complexes (PRC modulate the epigenetic status of key cell fate and developmental regulators in eukaryotes. The chromo domain protein like heterochromatin protein1 (LHP1 is a subunit of a plant PRC1-like complex in Arabidopsis thaliana and recognizes histone H3 lysine 27 trimethylation, a silencing epigenetic mark deposited by the PRC2 complex. We have identified and studied an LHP1-Interacting Factor2 (LIF2. LIF2 protein has RNA recognition motifs and belongs to the large hnRNP protein family, which is involved in RNA processing. LIF2 interacts in vivo, in the cell nucleus, with the LHP1 chromo shadow domain. Expression of LIF2 was detected predominantly in vascular and meristematic tissues. Loss-of-function of LIF2 modifies flowering time, floral developmental homeostasis and gynoecium growth determination. lif2 ovaries have indeterminate growth and produce ectopic inflorescences with severely affected flowers showing proliferation of ectopic stigmatic papillae and ovules in short-day conditions. To look at how LIF2 acts relative to LHP1, we conducted transcriptome analyses in lif2 and lhp1 and identified a common set of deregulated genes, which showed significant enrichment in stress-response genes. By comparing expression of LHP1 targets in lif2, lhp1 and lif2 lhp1 mutants we showed that LIF2 can either antagonize or act with LHP1. Interestingly, repression of the FLC floral transcriptional regulator in lif2 mutant is accompanied by an increase in H3K27 trimethylation at the locus, without any change in LHP1 binding, suggesting that LHP1 is targeted independently from LIF2 and that LHP1 binding does not strictly correlate with gene expression. LIF2, involved in cell identity and cell fate decision, may modulate the activity of LHP1 at specific loci, during specific developmental windows or in response to environmental cues that control cell fate determination. These results highlight a novel link between plant RNA

  4. The TatA component of the twin-arginine translocation system locally weakens the cytoplasmic membrane ofEscherichia coliupon protein substrate binding.

    Science.gov (United States)

    Hou, Bo; Heidrich, Eyleen S; Mehner-Breitfeld, Denise; Brüser, Thomas

    2018-03-13

    The twin-arginine translocation (Tat) system that comprises the TatA, TatB, and TatC components transports folded proteins across energized membranes of prokaryotes and plant plastids. It is not known, however, how the transport of this protein cargo is achieved. Favored models suggest that the TatA component supports transport by weakening the membrane upon full translocon assembly. Using Escherichia coli as model organism, we now demonstrate in vivo that the N-terminus of TatA can indeed destabilize the membrane, resulting in a lowered membrane energization in growing cells. We found that in full-length TatA, this effect is counterbalanced by its amphipathic helix. Consistent with these observations, the TatA N-terminus induced proton leakage in vitro , indicating membrane destabilization. Fluorescence quenching data revealed that substrate binding causes the TatA hinge region and the N-terminal part of the TatA amphipathic helix to move toward the membrane surface. In the presence of TatBC, substrate binding also reduced the exposure of a specific region in the amphipathic helix, indicating a participation of TatBC. Of note, the substrate-induced reorientation of the TatA amphipathic helix correlated with detectable membrane weakening. We therefore propose a two-state model in which membrane-destabilizing effects of the short TatA membrane anchor are compensated by the membrane-immersed N-terminal part of the amphipathic helix in a resting state. We conclude that substrate binding to TatABC complexes switches the position of the amphipathic helix, which locally weakens the membrane on demand to allow substrate translocation across the membrane. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

  5. Characteristic vibration patterns of odor compounds from bread-baking volatiles upon protein binding: density functional and ONIOM study and principal component analysis.

    Science.gov (United States)

    Treesuwan, Witcha; Hirao, Hajime; Morokuma, Keiji; Hannongbua, Supa

    2012-05-01

    As the mechanism underlying the sense of smell is unclear, different models have been used to rationalize structure-odor relationships. To gain insight into odorant molecules from bread baking, binding energies and vibration spectra in the gas phase and in the protein environment [7-transmembrane helices (7TMHs) of rhodopsin] were calculated using density functional theory [B3LYP/6-311++G(d,p)] and ONIOM [B3LYP/6-311++G(d,p):PM3] methods. It was found that acetaldehyde ("acid" category) binds strongly in the large cavity inside the receptor, whereas 2-ethyl-3-methylpyrazine ("roasted") binds weakly. Lys296, Tyr268, Thr118 and Ala117 were identified as key residues in the binding site. More emphasis was placed on how vibrational frequencies are shifted and intensities modified in the receptor protein environment. Principal component analysis (PCA) suggested that the frequency shifts of C-C stretching, CH(3) umbrella, C = O stretching and CH(3) stretching modes have a significant effect on odor quality. In fact, the frequency shifts of the C-C stretching and C = O stretching modes, as well as CH(3) umbrella and CH(3) symmetric stretching modes, exhibit different behaviors in the PCA loadings plot. A large frequency shift in the CH(3) symmetric stretching mode is associated with the sweet-roasted odor category and separates this from the acid odor category. A large frequency shift of the C-C stretching mode describes the roasted and oily-popcorn odor categories, and separates these from the buttery and acid odor categories.

  6. DNA and protein binding, double-strand DNA cleavage and cytotoxicity of mixed ligand copper(II) complexes of the antibacterial drug nalidixic acid.

    Science.gov (United States)

    Loganathan, Rangasamy; Ganeshpandian, Mani; Bhuvanesh, Nattamai S P; Palaniandavar, Mallayan; Muruganantham, Amsaveni; Ghosh, Swapan K; Riyasdeen, Anvarbatcha; Akbarsha, Mohammad Abdulkader

    2017-09-01

    The water soluble mixed ligand complexes [Cu(nal)(diimine)(H 2 O)](ClO 4 ) 1-4, where H(nal) is nalidixic acid and diimine is 2,2'-bipyridine (1), 1,10-phenanthroline (2), 5,6-dimethyl-1,10-phenanthroline (3), and 3,4,7,8-tetramethyl-1,10-phenanthroline (4), have been isolated. The coordination geometry around Cu(II) in 1 and that in the Density Functional Theory optimized structures of 1-4 has been assessed as square pyramidal. The trend in DNA binding constants (K b ) determined using absorption spectral titration (K b : 1, 0.79±0.1base pair. In contrast, 3 and 4 are involved in intimate hydrophobic interaction with DNA through the methyl substituents on phen ring, which is supported by viscosity and protein binding studies. DNA docking studies imply that 4 is involved preferentially in DNA major groove binding while 1-3 in minor groove binding and that all the complexes, upon removing the axially coordinated water molecule, bind in the major groove. Interestingly, 3 and 4 display prominent double-strand DNA cleavage while 1 and 2 effect only single-strand DNA cleavage in the absence of an activator. The complexes 3 and 4 show cytotoxicity higher than 1 and 2 against human breast cancer cell lines (MCF-7). The complex 4 induces apoptotic mode of cell death in cancer cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Structure–property reduced order model for viscosity prediction in single-component CO 2 -binding organic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Cantu, David C.; Malhotra, Deepika; Koech, Phillip K.; Heldebrant, David J.; Zheng, Feng (Richard); Freeman, Charles J.; Rousseau, Roger; Glezakou, Vassiliki-Alexandra

    2016-01-01

    CO2 capture from power generation with aqueous solvents remains energy intensive due to the high water content of the current technology, or the high viscosity of non-aqueous alternatives. Quantitative reduced models, connecting molecular structure to bulk properties, are key for developing structure-property relationships that enable molecular design. In this work, we describe such a model that quantitatively predicts viscosities of CO2 binding organic liquids (CO2BOLs) based solely on molecular structure and the amount of bound CO2. The functional form of the model correlates the viscosity with the CO2 loading and an electrostatic term describing the charge distribution between the CO2-bearing functional group and the proton-receiving amine. Molecular simulations identify the proton shuttle between these groups within the same molecule to be the critical indicator of low viscosity. The model, developed to allow for quick screening of solvent libraries, paves the way towards the rational design of low viscosity non-aqueous solvent systems for post-combustion CO2 capture. Following these theoretical recommendations, synthetic efforts of promising candidates and viscosity measurement provide experimental validation and verification.

  8. Sequential Proton Loss Electron Transfer in Deactivation of Iron(IV) Binding Protein by Tyrosine Based Food Components

    DEFF Research Database (Denmark)

    Tang, Ning; Skibsted, Leif Horsfelt

    2017-01-01

    to understand the relationship between density functional theory calculated molecular descriptors and kinetic data, which was further modeled by partial least squares for quantitative structure-activity relationship analysis. In addition, a three tyrosine residue containing protein, lysozyme, was also found...... by protonation of ferrylmyoglobin and facilitated proton transfer at acidic conditions. Enthalpy-entropy compensation effects were observed for the activation parameters (ΔH† and ΔS†), indicating the common reaction mechanism. Moreover, principal component analysis combined with heat map were performed...... to be able to reduce ferrylmyoglobin with a second order rate constant of 66 ± 28 L/mol/s as determined by a competitive kinetic method....

  9. Global transcriptional profiles of the copper responses in the cyanobacterium Synechocystis sp. PCC 6803.

    Directory of Open Access Journals (Sweden)

    Joaquin Giner-Lamia

    Full Text Available Copper is an essential element involved in fundamental processes like respiration and photosynthesis. However, it becomes toxic at high concentration, which has forced organisms to control its cellular concentration. We have recently described a copper resistance system in the cyanobacterium Synechocystis sp. PCC 6803, which is mediated by the two-component system, CopRS, a RND metal transport system, CopBAC and a protein of unknown function, CopM. Here, we report the transcriptional responses to copper additions at non-toxic (0.3 µM and toxic concentrations (3 µM in the wild type and in the copper sensitive copR mutant strain. While 0.3 µM copper slightly stimulated metabolism and promoted the exchange between cytochrome c6 and plastocyanin as soluble electron carriers, the addition of 3 µM copper catalyzed the formation of ROS, led to a general stress response and induced expression of Fe-S cluster biogenesis genes. According to this, a double mutant strain copRsufR, which expresses constitutively the sufBCDS operon, tolerated higher copper concentration than the copR mutant strain, suggesting that Fe-S clusters are direct targets of copper toxicity in Synechocystis. In addition we have also demonstrated that InrS, a nickel binding transcriptional repressor that belong to the CsoR family of transcriptional factor, was involved in heavy metal homeostasis, including copper, in Synechocystis. Finally, global gene expression analysis of the copR mutant strain suggested that CopRS only controls the expression of copMRS and copBAC operons in response to copper.

  10. Nude mice produce a T cell-derived antigen-binding factor that mediates the early component of delayed-type hypersensitivity.

    Science.gov (United States)

    Herzog, W R; Meade, R; Pettinicchi, A; Ptak, W; Askenase, P W

    1989-03-15

    The elicitation of delayed-type hypersensitivity (DTH) reactions in mice is caused by the sequential action of two different T cells. An early-acting, DTH-initiating T cell produces an Ag-specific T cell factor, that is analogous to IgE antibody and initiates DTH by sensitizing the local tissues for release of the vasoactive amine serotonin. In picryl chloride or oxazolone contact sensitivity, this T cell factor is Ag-specific, but MHC unrestricted. We, therefore, hypothesized that DTH-initiating T cells are primitive T cells with Ag receptors that can bind Ag without MHC restriction. In order to characterize the origin of this DTH-initiating T cell and the conditions that are necessary for its development, we contact-sensitized various strains of immunodeficient mice. Surprisingly, we found that the early phase of DTH was present in athymic nude mice. In contrast, the early component of DTH was absent in mice with severe combined immunodeficiency. These mice lack T and B cells, but have NK cells. These findings suggested that the early component of DTH was not caused by NK cells, and was caused by cells belonging to a lineage from a rearranging gene family. The early component of DTH in nude mice was Ag specific, was caused by MHC unrestricted Thy-1+ T cells, and was mediated by Ag-binding, Ag-specific T cell factors. We found that DTH-initiating, T cell-derived, Ag-binding molecules from nude mice and normal CBA/J mice had the same functional properties. The early component of DTH was elicited in two different systems (contact sensitivity and SRBC-specific DTH) in two strains of nude mice (BALB/c athymic nudes and CByB6F1/J-nu) from two different suppliers, but not in BALB/c and athymic nudes from a third supplier. From these findings we concluded that DTH-initiating T cells, which produce IgE-like Ag-specific T cell factors, are present in some strains of athymic nude mice and thus are relatively thymic independent T cells.

  11. Copper (II)

    African Journals Online (AJOL)

    CLEMENT O BEWAJI

    ABSTRACT: A Schiff base was prepared from the reaction of 2 - amino - 3 – methylbutanoic acid and 2, 4 - pentanedione. The reaction of the prepared Schiff base with ethanolic solution of copper (II) chloride formed diaquo bis( N – 2 – amino – 3 - methylbutyl - 2, 4 - pentanedionato) copper (II) complex. The Schiff base is ...

  12. Studies of copper transport in mammalian cells using copper radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Camakaris, J.; Voskoboinik, I.; Brooks, H.; Greenough, M. [University of Melbourne, Parkville, VIC (Australia). Department of Genetics; Smith, S. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Radiopharmaceuticals Division; Mercer, J. [Deakin University, Clayton, VIC (Australia). Centre of Cellular and Molecular Biology

    1998-12-31

    The trace element copper poses a major problem for all organisms. It is essential as a number of vital enzymes require it. Copper deficiency can lead to neurological disorders, osteoporosis and weakening of arteries. However Cu is also highly toxic and homeostatic mechanisms have evolved to maintain Cu at levels which satisfy requirements but do not cause toxicity. Toxicity is mediated by the oxidative capacity of Cu and its ability to generate toxic free radicals. There are several acquired and inherited diseases due to either Cu toxicity or Cu deficiency. The study of these diseases facilitates identification of genes and proteins involved in copper homeostasis, and this in turn will provide rational therapeutic approaches. Using the copper radioisotopes {sup 64}Cu (t1/2 = 12.8 hr) and {sup 67}Cu (t1/2 = 61 hr) we have developed a number of systems for studying copper transport in mammalian cells. These include investigation of copper uptake, copper efflux and ligand blot assays for Cu-binding proteins. Our studies have focused on Menkes disease which is an inherited and usually lethal copper deficiency disorder in humans. We have demonstrated that the Menkes protein is directly involved as a copper efflux pump in mammalian cells. Using cells overexpressing the Menkes protein we have provided the first biochemical evidence that this functions as a Cu translocating (across the membrane) P-type ATPase (Voskoboinik et al., FEBS Letters, in press). These studies were carried out using purified plasma membrane vesicles. We are now carrying out structure- function studies on this protein using targeted mutations and assaying using the radiocopper vesicle assay. Recently we have commenced studies on the role of amyloid precursor protein (APP) in copper transport and relationship of this to Alzheimers disease

  13. The copper-transporting ATPase pump and its potential role in copper-tolerance

    Science.gov (United States)

    Katie Ohno; C.A. Clausen; Frederick Green; G. Stanosz

    2016-01-01

    Copper-tolerant brown-rot decay fungi exploit intricate mechanisms to neutralize the efficacy of copper-containing preservative formulations. The production and accumulation oxalate is the most widely recognized theory regarding the mechanism of copper-tolerance in these fungi. The role of oxalate, however, may be only one part of a series of necessary components...

  14. Design and synthesis of enantiomeric (R)- and (S)-copper(II) and diorganotin(IV)-based antitumor agents: their in vitro DNA binding profile, cleavage efficiency and cytotoxicity studies.

    Science.gov (United States)

    Arjmand, Farukh; Muddassir, Mohd; Yousuf, Imtiyaz

    2014-07-05

    New chiral reduced Schiff base ligands (R)/(S)-2-(2-hydroxy-1-phenylethylaminomethyl)phenol (L), (R)/(S)-2-(benzylamino)-2-phenylethanol (L') and their Cu(II)/organotin(IV) complexes (1-4) were synthesized and thoroughly characterized. Preliminary in vitro DNA binding studies of (R)- and (S)-enantiomeric pairs of ligands L, L' and complexes 1-4 were carried out employing UV-vis, fluorescence and circular dichroic techniques to evaluate their enantioselective DNA binding potential, thereby to act as antitumor chemotherapeutic drug entities. The observations demonstrated that S-enantiomer of Cu(II) complex, 1 binds more avidly to DNA in comparison to its R-enantiomeric form and organotin(IV) complex 2. This was further established by Kb and Ksv values of ligands L and L' and (S)-/(R)-1-4 complexes, which demonstrated multifold increase in case of S-enantiomer of copper complex 1 in comparison to its R-enantiomeric form. This clearly demonstrates the chiral preference of S-enantiomer over R-enantiomer and its potency to act as a chemotherapeutic agent. Cleavage studies of 1-4 with pBR322 plasmid DNA were carried out, noticeably, S-enantiomer of complex 1 exhibited effective DNA cleavage efficiency in absence of external agents. The cytotoxicity of ligands L and L' and (S)-/(R)-1-4 complexes was examined on a panel of 19 human tumor cell lines of different histological origins by SRB assay. In the both the cases, the S-enantiomer of complex 1 and 3 revealed remarkably good cytotoxic activity (GI50 values complexes demonstrated moderate cytotoxic activity (GI50 values <40). Copyright © 2014 Elsevier B.V. All rights reserved.

  15. Adhesive performance of silver-palladium-copper-gold alloy and component metals bonded with organic sulfur-based priming agents and a tri-n-butylborane initiated luting material.

    Science.gov (United States)

    Yamashita, Miyuki; Koizumi, Hiroyasu; Ishii, Takaya; Nakayama, Daisuke; Oba, Yusuke; Matsumura, Hideo

    2013-01-01

    The purpose of the current study was to evaluate the effect of thione-based metal priming agents on the adhesive behavior of a Ag-Pd-Cu-Au alloy and component metals bonded with an acrylic resin. Disk specimens (10 mm in diameter by 3 mm thick) were prepared from a silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy (Castwell M.C.12), high-purity silver, palladium, copper and gold. Four single-liquid priming agents containing organic sulfur compound (Alloy Primer, Metaltite, M.L. Primer and V-Primer) and three acidic priming agents (All Bond II Primer B, Estenia Opaque Primer and Super-Bond Liquid) were assessed. The metal specimens were flat-ground with abrasive papers, primed with one of the agents and bonded with a tri-n-butylborane initiated resin. The shear bond strengths were determined both before and after repeated thermocycling (5°C and 55°C, 1 min each, 20,000 cycles). The results were statistically analyzed with a non-parametric procedure (p = 0.05 level). The post-thermocycling bond strengths in MPa (median; n = 11) associated with the Alloy Primer, Metaltite, M.L. Primer and V-Primer materials were, respectively, 20.8, 22.8, 17.8 and 18.4 for the Ag-Pd-Cu-Au alloy; 19.6, 21.9, 14.4 and 20.1 for silver; 5.4, 4.5, 12.8 and 5.3 for palladium; 17.1, 19.2, 0.7 and 6.6 for copper; and 18.5, 17.7, 22.8 and 15.4 for gold. It can be concluded that the use of the four priming agents, which are based on organic sulfur compounds, effectively enhanced bonding to the Ag-Pd-Cu-Au alloy and the component metals, although the bonding performance varied among the priming agents and metal elements. The priming agents appeared to have more of an effect on the alloy, silver and gold than on the palladium and copper.

  16. Synthesis, characterization, X-ray crystal structure, DFT calculation, DNA binding, and antimicrobial assays of two new mixed-ligand copper(II) complexes

    Science.gov (United States)

    Ebrahimipour, S. Yousef; Sheikhshoaie, Iran; Mohamadi, Maryam; Suarez, Sebastian; Baggio, Ricardo; Khaleghi, Moj; Torkzadeh-Mahani, Masoud; Mostafavi, Ali

    2015-05-01

    Two new Cu(II) complexes, [Cu(L)(phen)] (1), [Cu(L)(bipy)] (2), where L2- = (3-methoxy-2oxidobenzylidene)benzohydrazidato, phen = 1,10 phenanthroline, and bipy = 2,2‧ bipyridine, were prepared and fully characterized using elemental analyses, FT-IR, molar conductivity, and electronic spectra. The structures of both complexes were also determined by X-ray diffraction. It was found that, both complexes possessed square pyramidal coordination environment in which, Cu(II) ions were coordinated by donor atoms of HL and two nitrogens of heterocyclic bases. Computational studies were performed using DFT calculations at B3LYP/6-311+G(d,p) level of theory. DNA binding activities of these complexes were also investigated using electronic absorption, competitive fluorescence titration and cyclic voltammetry studies. The obtained results indicated that binding of the complexes to DNA was of intercalative mode. Furthermore, antimicrobial activities of these compounds were screened against microorganisms.

  17. DNA binding, DNA cleavage and BSA interaction of a mixed-ligand copper(II) complex with taurine Schiff base and 1,10-phenanthroline.

    Science.gov (United States)

    Li, Lianzhi; Guo, Qiong; Dong, Jianfang; Xu, Tao; Li, Jinghong

    2013-08-05

    The DNA-binding properties and DNA-cleavage activities of a Cu(II) complex, [Cu(sal-tau(phen)]·1.5H2O (sal-tau=a Schiff base derived from salicylaldehyde and taurine, phen=1,10-phenanthroline), have been investigated by using UV-Vis absorption, fluorescence, circular dichroism (CD) spectra and agarose gel electrophoresis. Results indicated that this Cu(II) complex can bind to calf thymus DNA (CT-DNA) via an intercalative mode and shows efficient cleavage activity in the absence and presence of reducer. Its intrinsic binding constant Kb (1.66×10(4)M(-1)) was calculated by absorption spectra and its linear Stern-Volmer quenching constant K(sq) (3.05) was obtained from florescence spectroscopy, as well as the cleaving reaction rate constant k1 (2.0×10(-4)s(-1)) was acquired from agarose gel electrophoresis. Meanwhile, the interactions of the complex with BSA have also been studied by spectroscopy. Results showed that the complex could quench the intrinsic fluorescence of bovine serum albumin (BSA) remarkably through a static quenching process, and induce a conformational change with the loss of helical stability of protein. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Evaluation of allergenic potential for rice seed protein components utilizing a rice proteome database and an allergen database in combination with IgE-binding of recombinant proteins.

    Science.gov (United States)

    Hirano, Kana; Hino, Shingo; Oshima, Kenzi; Nadano, Daita; Urisu, Atsuo; Takaiwa, Fumio; Matsuda, Tsukasa

    2016-01-01

    Among 131 rice endosperm proteins previously identified by MS-based proteomics, most of the proteins showed low or almost no sequence similarity to known allergens in databases, whereas nine proteins did it significantly. The sequence of two proteins showed high overall identity with Hsp70-like hazel tree pollen allergen (Cor a 10) and barley α-amylase (Hor v 16), respectively, whereas the others showed low identity (28-58%) with lemon germin-like protein (Cit l 1), corn zein (Zea m 50 K), wheat chitinase-like xylanase inhibitor (Tri a XI), and kinase-like pollen allergen of Russian thistle (Sal k 1). Immuno-dot blot analysis showed that recombinant proteins for these rice seed homologs were positive in the IgE-binding, but not necessarily similarity dependent, from some allergic patients. These results suggest that utilization of proteome and sequence databases in combination with IgE-binding analysis was effective to screen and evaluate allergenic potential of rice seed protein components.

  19. FleQ of Pseudomonas putida KT2440 is a multimeric cyclic diguanylate binding protein that differentially regulates expression of biofilm matrix components.

    Science.gov (United States)

    Molina-Henares, María Antonia; Ramos-González, María Isabel; Daddaoua, Abdelali; Fernández-Escamilla, Ana María; Espinosa-Urgel, Manuel

    2017-01-01

    The intracellular signal molecule cyclic di-GMP (c-di-GMP) is an important element in regulation of biofilm formation by bacteria. In Pseudomonas aeruginosa, FleQ functions as a c-di-GMP-dependent transcriptional regulator of expression of flagellar genes and the exopolysaccharide (EPS) Pel, a component of the biofilm extracellular matrix. In the plant-beneficial bacterium Pseudomonas putida KT2440, a mutation in fleQ reduces biofilm formation and colonization of plant surfaces. Using isothermal titration calorimetry and electrophoretic mobility shift assays, we show in this work that FleQ of P. putida interacts with c-di-GMP and directly binds the promoter regions of flagellar and EPS genes. Data obtained by analytical gel filtration and ultracentrifugation indicate that FleQ is in multiple oligomeric states in solution (dimers, tetramers and hexamers), which do not show altered equilibrium in the presence of c-di-GMP. DNA binding is independent of c-diGMP, although it is favored by the second messenger in the case of the promoter of the operon responsible for synthesis of the species-specific EPS Pea. Analysis of expression using transcriptional fusions showed an influence of FleQ upon two of the four EPS operons under regular growth conditions. Finally, a consensus sequence for promoter recognition by FleQ in P. putida is also proposed. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  20. Tryptophan phosphorescence spectroscopy reveals that a domain in the NAD(H)-binding component (dI) of transhydrogenase from Rhodospirillum rubrum has an extremely rigid and conformationally homogeneous protein core

    NARCIS (Netherlands)

    Broos, J; Gabellieri, E; van Boxel, GI; Jackson, JB; Strambini, GB; Strambini, Giovanni B.

    2003-01-01

    The characteristics of tryptophan phosphorescence from the NAD(H)-binding component (dI) component of Rhodospirillum rubrum transhydrogenase are described. This enzyme couples hydride transfer between NAD( H) and NADP( H) to proton translocation across a membrane and is only active as a dimer.

  1. Evaluation of immobilized metal-ion affinity chromatography and electrospray ionization tandem mass spectrometry for recovery and identification of copper(II-binding ligands in seawater using the model ligand 8-hydroxyquinoline

    Directory of Open Access Journals (Sweden)

    Richard L Nixon

    2016-11-01

    Full Text Available Complexation by organic ligands dominates the speciation of iron (Fe, copper (Cu, and other bioactive trace metals in seawater, controlling their bioavailability and distribution in the marine environment. Several classes of high-affinity Fe-binding ligands (siderophores have been identified in seawater but the chemical structures of marine Cu-complexing ligands remain unknown. Immobilized metal-ion affinity chromatography (IMAC allows Cu ligands to be isolated from bulk dissolved organic matter (DOM in seawater and separated into fractions which can be characterized independently using electrochemical and spectroscopic techniques. Attempts have been made to combine IMAC with electrospray ionization mass spectrometry (ESI-MS to characterize marine Cu ligands, but results have proven inconclusive due to the lack of tandem mass spectrometry (MS/MS data to confirm ligand recovery. We used 8-hydroxyquinoline (8-HQ, a well-characterized model ligand that forms strong 1:2 metal:ligand complexes with Cu2+ at pH 8 (log β2 = 18.3, to evaluate Cu(II-IMAC and ESI-MS/MS for recovery and identification of copper(II-complexing ligands in seawater. One-litre samples of 0.45µm-filtered surface seawater were spiked with 8-HQ at low concentrations (up to 100 nM and fractionated by IMAC. Fractions eluted with acidified artificial seawater were desalted and re-suspended in methanol via solid-phase extraction (SPE to obtain extracts suitable for ESI-MS analysis. Recovery of 8-HQ by Cu(II-IMAC was confirmed unambiguously by MS/MS and found to average 81% based upon accurate quantitation via multiple reaction monitoring (MRM. Cu(II-IMAC fractionation of unspiked seawater using multiple UV detection wavelengths suggests an optimal fraction size of 2 mL for isolating and analyzing Cu ligands with similar properties.

  2. Progesterone receptor membrane component 1 inhibits the activity of drug-metabolizing cytochromes P450 and binds to cytochrome P450 reductase.

    Science.gov (United States)

    Szczesna-Skorupa, Elzbieta; Kemper, Byron

    2011-03-01

    Progesterone receptor membrane component 1 (PGRMC1) has been shown to interact with several cytochromes P450 (P450s) and to activate enzymatic activity of P450s involved in sterol biosynthesis. We analyzed the interactions of PGRMC1 with the drug-metabolizing P450s, CYP2C2, CYP2C8, and CYP3A4, in transfected cells. Based on coimmunoprecipitation assays, PGRMC1 bound efficiently to all three P450s, and binding to the catalytic cytoplasmic domain of CYP2C2 was much more efficient than to a chimera containing only the N-terminal transmembrane domain. Down-regulation of PGRMC1 expression levels in human embryonic kidney 293 and HepG2 cell lines stably expressing PGRMC1-specific small interfering RNA had no effect on the endoplasmic reticulum localization and expression levels of P450s, whereas enzymatic activities of CYP2C2, CYP2C8, and CYP3A4 were slightly higher in PGRMC1-deficient cells. Cotransfection of cells with P450s and PGRMC1 resulted in PGRMC1 concentration-dependent inhibition of the P450 activities, and this inhibition was partially reversed by increased expression of the P450 reductase (CPR). In contrast, CYP51 activity was decreased by down-regulation of PGRMC1 and expression of PGRMC1 in the PGRMC1-deficient cells increased CYP51 activity. In cells cotransfected with CPR and PGRMC1, strong binding of CPR to PGRMC1 was observed; however, in the presence of CYP2C2, interaction of PGRMC1 with CPR was significantly reduced, suggesting that CYP2C2 competes with CPR for binding to PGRMC1. These data show that in contrast to sterol synthesizing P450, PGRMC1 is not required for the activities of several drug-metabolizing P450s, and its overexpression inhibits those P450 activities. Furthermore, PGRMC1 binds to CPR, which may influence P450 activity.

  3. Multi-component quantitation of meso/nanostructural surfaces and its application to local chemical compositions of copper meso/nanostructures self-organized on silica

    Science.gov (United States)

    Huang, Chun-Yi; Chang, Hsin-Wei; Chang, Che-Chen

    2018-03-01

    Knowledge about the chemical compositions of meso/nanomaterials is fundamental to development of their applications in advanced technologies. Auger electron spectroscopy (AES) is an effective analysis method for the characterization of meso/nanomaterial structures. Although a few studies have reported the use of AES for the analysis of the local composition of these structures, none have explored in detail the validity of the meso/nanoanalysis results generated by the AES instrument. This paper addresses the limitations of AES and the corrections necessary to offset them for this otherwise powerful meso/nanoanalysis tool. The results of corrections made to the AES multi-point analysis of high-density copper-based meso/nanostructures provides major insights into their local chemical compositions and technological prospects, which the primitive composition output of the AES instrument failed to provide.

  4. Copper welding; Les liaisons du cuivre

    Energy Technology Data Exchange (ETDEWEB)

    Monneau, Ph. [SDMS, 38 - Saint-Romans (France)

    2000-07-01

    The following categories of manufactured copper: Cu-c ( > 99.95% copper and less than 0.0003% phosphor) and Cu-OF (oxygen free copper) are useful in vacuum or ultra-vacuum techniques. Homogeneous binding (or heterogeneous with other metals) are mainly performed by welding (TIG, MIG, FE) or by brazing at high or low temperatures. In this article these different methods are reviewed with pros and cons, and several applications are presented, particularly the designing of high frequency resonator cavities for GANIL accelerator, these cavities were made out of solid copper. (A.C.)

  5. The effects of copper proximity on oxalate production in Fibroporia radiculosa

    Science.gov (United States)

    Katie M. Jenkins; Carol A. Clausen; Frederick Green III

    2014-01-01

    Copper remains a key component used in wood preservatives available today. However, the observed tolerance of several critical wood rotting organisms continues to be problematic. Tolerance to copper has been linked to the production and accumulation of oxalate, which precipitates copper into insoluble copper-oxalate crystals, thus inactivating copper ions. The purpose...

  6. Copper methanobactin: a molecule whose time has come

    OpenAIRE

    Balasubramanian, Ramakrishnan; Rosenzweig, Amy C.

    2008-01-01

    Copper plays a key role in the physiology of methanotrophs. One way that these bacteria meet their high copper requirement is by the biosynthesis and release of high affinity copper-binding compounds called methanobactins. Recent advances in methanobactin characterization include the first crystal structure, detailed spectroscopic analyses, and studies of metal ion specificity. Methanobactin may function in copper uptake, regulation of methane monooxygenase expression, protection against copp...

  7. Copper Toxicity in the San Francisco Bay-Delta

    OpenAIRE

    Buck, Kristen N.

    2012-01-01

    San Francisco Bay has high dissolved copper concentrations—relative to nearby coastal waters—that often approach federal water quality standards put in place to protect sensitive marine life. But, how toxic is this copper? Previous studies by other researchers have suggested that metal-binding compounds known as ligands can “grab up” more than 99.9 percent of the total available dissolved copper in seawater, rendering that copper biologically unavailable. Microorganisms that need tra...

  8. Increased type I collagen content and DNA binding activity of a single-stranded, cytosine-rich sequence in the high-salt buffer protein extract of the copper-deficient rat heart.

    Science.gov (United States)

    Zeng, Huawei; Saari, Jack T

    2004-11-01

    Dietary copper (Cu) deficiency not only causes a hypertrophic cardiomyopathy but also increases cancer risk in rodent models. However, a possible alteration in gene expression has not been fully examined. The present study was undertaken to determine the effect of Cu deficiency on protein profiles in rat heart tissue. Male Sprague-Dawley rats were fed diets that were either a Cu-adequate diet (6.0 microg Cu/g diet, n = 6) or a Cu-deficient diet (0.3 microg Cu/g diet, n = 6) for 5 weeks. The high-salt buffer (HSB) protein extract from heart tissue of Cu-deficient, but not Cu-adequate rats showed a 132 kDa protein band by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. This protein band stained pink with Coomassie Blue, suggesting the presence of collagens or other proline-rich proteins. Dot immunoblotting demonstrated that total type I collagen was increased by 110% in HSB protein extract from Cu-deficient, relative to Cu-adequate, rats. Liquid chromatography with mass spectrometry analysis indicated that the 132 kDa protein band contained a collagen alpha (I) chain precursor as well as a leucine-rich protein 130 (LRP130) in HSB protein extract from Cu-deficient but not Cu-adequate rats. A gel shift assay showed that HSB protein extract from Cu-deficient rats bound to a single-stranded cytosine-rich DNA with higher affinity than the extract of Cu-adequate rats, similar to reports of an increase in LRP130 single-stranded DNA binding activity in several types of tumor cells. Collectively, these results not only suggest an additional feature of altered collagen metabolism with Cu deficiency but also demonstrate for the first time an increase in single-stranded cytosine-rich DNA binding in Cu-deficient rat heart.

  9. Copper accumulation by stickleback nests containing spiggin.

    Science.gov (United States)

    Pinho, G L L; Martins, C M G; Barber, I

    2016-07-01

    The three-spined stickleback is a ubiquitous fish of marine, brackish and freshwater ecosystems across the Northern hemisphere that presents intermediate sensitivity to copper. Male sticklebacks display a range of elaborate reproductive behaviours that include nest construction. To build the nests, each male binds nesting material together using an endogenous glycoprotein nesting glue, known as 'spiggin'. Spiggin is a cysteine-rich protein and, therefore, potentially binds heavy metals present in the environment. The aim of this study was to investigate the capacity of stickleback nests to accumulate copper from environmental sources. Newly built nests, constructed by male fish from polyester threads in laboratory aquaria, were immersed in copper solutions ranging in concentration from 21.1-626.6 μg Cu L(-1). Bundles of polyester threads from aquaria without male fish were also immersed in the same copper solutions. After immersion, nests presented higher amounts of copper than the thread bundles, indicating a higher capacity of nests to bind this metal. A significant, positive correlation between the concentration of copper in the exposure solution and in the exposed nests was identified, but there was no such relationship for thread bundles. Since both spiggin synthesis and male courtship behaviour are under the control of circulating androgens, we predicted that males with high courtship scores would produce and secrete high levels of the spiggin protein. In the present study, nests built by high courtship score males accumulated more copper than those built by low courtship score males. Considering the potential of spiggin to bind metals, the positive relationship between fish courtship and spiggin secretion seems to explain the higher amount of copper on the nests from the fish showing high behaviour scores. Further work is now needed to determine the consequences of the copper binding potential of spiggin in stickleback nests for the health and survival of

  10. Components of the Arabidopsis C-Repeat/Dehydration-Responsive Element Binding Factor Cold-Response Pathway Are Conserved in Brassica napus and Other Plant Species1

    Science.gov (United States)

    Jaglo, Kirsten R.; Kleff, Susanne; Amundsen, Keenan L.; Zhang, Xin; Haake, Volker; Zhang, James Z.; Deits, Thomas; Thomashow, Michael F.

    2001-01-01

    Many plants increase in freezing tolerance in response to low, nonfreezing temperatures, a phenomenon known as cold acclimation. Cold acclimation in Arabidopsis involves rapid cold-induced expression of the C-repeat/dehydration-responsive element binding factor (CBF) transcriptional activators followed by expression of CBF-targeted genes that increase freezing tolerance. Here, we present evidence for a CBF cold-response pathway in Brassica napus. We show that B. napus encodes CBF-like genes and that transcripts for these genes accumulate rapidly in response to low temperature followed closely by expression of the cold-regulated Bn115 gene, an ortholog of the Arabidopsis CBF-targeted COR15a gene. Moreover, we show that constitutive overexpression of the Arabidopsis CBF genes in transgenic B. napus plants induces expression of orthologs of Arabidopsis CBF-targeted genes and increases the freezing tolerance of both nonacclimated and cold-acclimated plants. Transcripts encoding CBF-like proteins were also found to accumulate rapidly in response to low temperature in wheat (Triticum aestivum L. cv Norstar) and rye (Secale cereale L. cv Puma), which cold acclimate, as well as in tomato (Lycopersicon esculentum var. Bonny Best, Castle Mart, Micro-Tom, and D Huang), a freezing-sensitive plant that does not cold acclimate. An alignment of the CBF proteins from Arabidopsis, B. napus, wheat, rye, and tomato revealed the presence of conserved amino acid sequences, PKK/RPAGRxKFxETRHP and DSAWR, that bracket the AP2/EREBP DNA binding domains of the proteins and distinguish them from other members of the AP2/EREBP protein family. We conclude that components of the CBF cold-response pathway are highly conserved in flowering plants and not limited to those that cold acclimate. PMID:11706173

  11. Components of the Arabidopsis C-repeat/dehydration-responsive element binding factor cold-response pathway are conserved in Brassica napus and other plant species.

    Science.gov (United States)

    Jaglo, K R; Kleff, S; Amundsen, K L; Zhang, X; Haake, V; Zhang, J Z; Deits, T; Thomashow, M F

    2001-11-01

    Many plants increase in freezing tolerance in response to low, nonfreezing temperatures, a phenomenon known as cold acclimation. Cold acclimation in Arabidopsis involves rapid cold-induced expression of the C-repeat/dehydration-responsive element binding factor (CBF) transcriptional activators followed by expression of CBF-targeted genes that increase freezing tolerance. Here, we present evidence for a CBF cold-response pathway in Brassica napus. We show that B. napus encodes CBF-like genes and that transcripts for these genes accumulate rapidly in response to low temperature followed closely by expression of the cold-regulated Bn115 gene, an ortholog of the Arabidopsis CBF-targeted COR15a gene. Moreover, we show that constitutive overexpression of the Arabidopsis CBF genes in transgenic B. napus plants induces expression of orthologs of Arabidopsis CBF-targeted genes and increases the freezing tolerance of both nonacclimated and cold-acclimated plants. Transcripts encoding CBF-like proteins were also found to accumulate rapidly in response to low temperature in wheat (Triticum aestivum L. cv Norstar) and rye (Secale cereale L. cv Puma), which cold acclimate, as well as in tomato (Lycopersicon esculentum var. Bonny Best, Castle Mart, Micro-Tom, and D Huang), a freezing-sensitive plant that does not cold acclimate. An alignment of the CBF proteins from Arabidopsis, B. napus, wheat, rye, and tomato revealed the presence of conserved amino acid sequences, PKK/RPAGRxKFxETRHP and DSAWR, that bracket the AP2/EREBP DNA binding domains of the proteins and distinguish them from other members of the AP2/EREBP protein family. We conclude that components of the CBF cold-response pathway are highly conserved in flowering plants and not limited to those that cold acclimate.

  12. binding protein (HABP1)

    Indian Academy of Sciences (India)

    Unknown

    adsorbed on carbon coated copper grid (400 mesh) for. 5 min at room temperature. The grids were subsequently .... and inhibition by GAGs and DMA were determined on polystyrene wells of microtitre plates (Costar, ... for binding inhibition assays was carried out by mixing equal volumes of the conjugate and the inhibitor at ...

  13. binding protein (HABP1)

    Indian Academy of Sciences (India)

    Unknown

    of HA in a concentration-dependent manner, suggesting its multiligand affinity amongst carbohydrates. rHABP1 shows differential affinity ... site is seen to correspond to the carbohydrate-binding site in E-selectin, which has similarity in the ... adsorbed on carbon coated copper grid (400 mesh) for. 5 min at room temperature.

  14. Binding of heavy metals to derivatives of cholesterol and sodium dodecyl sulfate

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadi, S.; Batchelor, B.; Koseoglu, S.S. [Texas A and M Univ., College Station, TX (United States); Huang, Y.C.

    1995-09-01

    The binding behaviors of five metals (cadmium, copper, nickel, lead, and zinc), individually at pH 6 and collectively at pHs 6 and 3, to deoxycholic acid (DCA) and taurocholic acid (TCA) were compared with those of sodium dodecyl sulfate (SDS) using a continuous diafiltration method. DCA and SDS have been successfully applied in micellar-enhanced ultrafiltration (MEUF) for metal removal from water. In this study, SDS exhibits the strongest binding in the single-component experiments while DCA binds the most in the multicomponent trials. TCA does not show any significant biding compared with DCA and SDS. Overall the molar binding ratios of the mixture at pH 3 were well below those of the other two solutions. This diafiltration technique quantifies the binding characteristics of a surfactant by generating sorption isotherms and determining the intrinsic association constraints with corresponding number of binding sites. These parameters can be useful in designing an efficient MEUF system.

  15. Mgm101p is a novel component of the mitochondrial nucleoid that binds DNA and is required for the repair of oxidatively damaged mitochondrial DNA

    International Nuclear Information System (INIS)

    Meeusen, S.; Tieu, Q.; Wong, E.; Weiss, E.; Schieltz, D.; Yates, J.R.; Nunnari, J.

    1999-01-01

    Maintenance of mitochondrial DNA (mtDNA) during cell division is required for progeny to be respiratory competent. Maintenance involves the replication, repair, assembly, segregation, and partitioning of the mitochondrial nucleoid. MGM101 has been identified as a gene essential for mtDNA maintenance in S. cerevisiae, but its role is unknown. Using liquid chromatography coupled with tandem mass spectrometry, we identified Mgm101p as a component of highly enriched nucleoids, suggesting that it plays a nucleoid-specific role in maintenance. Subcellular fractionation, indirect immunofluorescence and GFP tagging show that Mgm101p is exclusively associated with the mitochondrial nucleoid structure in cells. Furthermore, DNA affinity chromatography of nucleoid extracts indicates that Mgm101p binds to DNA, suggesting that its nucleoid localization is in part due to this activity. Phenotypic analysis of cells containing a temperature sensitive mgm101 allele suggests that Mgm101p is not involved in mtDNA packaging, segregation, partitioning or required for ongoing mtDNA replication. We examined Mgm101p's role in mtDNA repair. As compared with wild-type cells, mgm101 cells were more sensitive to mtDNA damage induced by UV irradiation and were hypersensitive to mtDNA damage induced by gamma rays and H2O2 treatment. Thus, we propose that Mgm101p performs an essential function in the repair of oxidatively damaged mtDNA that is required for the maintenance of the mitochondrial genome. (author)

  16. Multi-component adsorption model for pellicle formation: the influence of salivary proteins and non-salivary phospho proteins on the binding of histatin 5 onto hydroxyapatite.

    Science.gov (United States)

    Yin, A; Margolis, H C; Yao, Y; Grogan, J; Oppenheim, F G

    2006-02-01

    The acquired enamel pellicle formed by selective adsorption of proteins in whole saliva is a protective integument on the tooth surface. The purpose of the present study was to investigate the formation of human acquired enamel pellicle using an in vitro hydroxyapatite (HA) model and 3H-histatin 5 to allow accurate measurement of histatin 5 binding in a multi-component experimental system. A binary system was employed by mixing 3H-histatin 5 with one unlabeled protein prior to incubation with HA or by first incubating 3H-histatin 5 with the HA which had been pre-coated with one of a panel of unlabeled proteins (human albumin, salivary amylase, lysozyme, acidic PIFs, statherin, the N-terminal fragment of statherin, and egg yolk phosvitin). A ternary system was employed by mixing 3H-histatin 5 with HA sequentially pre-coated with two different unlabeled proteins, including recombinant histatin 1. The results showed that only salivary statherin and egg yolk phosvitin promote histatin 5 adsorption significantly. The amount of histatin 5 adsorbed was also found to increase as a function of the amount of phosvitin and statherin used to pre-coat HA up to a maximum level that was two- to four-fold greater than that observed on untreated HA. These data suggest that specific protein-protein interactions may play important roles in pellicle formation in vivo.

  17. Uptake and internalisation of copper by three marine microalgae: comparison of copper-sensitive and copper-tolerant species.

    Science.gov (United States)

    Levy, Jacqueline L; Angel, Brad M; Stauber, Jennifer L; Poon, Wing L; Simpson, Stuart L; Cheng, Shuk Han; Jolley, Dianne F

    2008-08-29

    Although it has been well established that different species of marine algae have different sensitivities to metals, our understanding of the physiological and biochemical basis for these differences is limited. This study investigated copper adsorption and internalisation in three algal species with differing sensitivities to copper. The diatom Phaeodactylum tricornutum was particularly sensitive to copper, with a 72-h IC50 (concentration of copper to inhibit growth rate by 50%) of 8.0 microg Cu L(-1), compared to the green algae Tetraselmis sp. (72-h IC50 47 microg Cu L(-1)) and Dunaliella tertiolecta (72-h IC50 530 microg Cu L(-1)). At these IC50 concentrations, Tetraselmis sp. had much higher intracellular copper (1.97+/-0.01 x 10(-13)g Cu cell(-1)) than P. tricornutum (0.23+/-0.19 x 10(-13)g Cu cell(-1)) and D. tertiolecta (0.59+/-0.05 x 10(-13)g Cu cell(-1)), suggesting that Tetraselmis sp. effectively detoxifies copper within the cell. By contrast, at the same external copper concentration (50 microg L(-1)), D. tertiolecta appears to better exclude copper than Tetraselmis sp. by having a slower copper internalisation rate and lower internal copper concentrations at equivalent extracellular concentrations. The results suggest that the use of internal copper concentrations and net uptake rates alone cannot explain differences in species-sensitivity for different algal species. Model prediction of copper toxicity to marine biota and understanding fundamental differences in species-sensitivity will require, not just an understanding of water quality parameters and copper-cell binding, but also further knowledge of cellular detoxification mechanisms.

  18. Construction of a high efficiency copper adsorption bacterial system via peptide display and its application on copper dye polluted wastewater.

    Science.gov (United States)

    Maruthamuthu, Murali Kannan; Nadarajan, Saravanan Prabhu; Ganesh, Irisappan; Ravikumar, Sambandam; Yun, Hyungdon; Yoo, Ik-Keun; Hong, Soon Ho

    2015-11-01

    For the construction of an efficient copper waste treatment system, a cell surface display strategy was employed. The copper adsorption ability of recombinant bacterial strains displaying three different copper binding peptides were evaluated in LB Luria-Bertani medium (LB), artificial wastewater, and copper phthalocyanine containing textile dye industry wastewater samples. Structural characteristics of the three peptides were also analyzed by similarity-based structure modeling. The best binding peptide was chosen for the construction of a dimeric peptide display and the adsorption ability of the monomeric and dimeric peptide displayed strains were compared. The dimeric peptide displayed strain showed superior copper adsorption in all three tested conditions (LB, artificial wastewater, and textile dye industry wastewater). When the strains were exposed to copper phthalocyanine dye polluted wastewater, the dimeric peptide display [543.27 µmol/g DCW dry cell weight (DCW)] showed higher adsorption of copper when compared with the monomeric strains (243.53 µmol/g DCW).

  19. Adsorption of aqueous copper on peanut hulls

    Science.gov (United States)

    Davis, Kanika Octavia

    A method was established for measuring the adsorption of Cu(II) from aqueous solution to unmodified and modified peanut hulls at constant temperature and pH. Modification of the hulls was performed by oxidation with alkaline hydrogen peroxide. During the modification process, the hydrogen peroxide solubilizes the lignin component, making the surface more porous which increases the availability of binding sites, while simultaneously oxidizing the cellulose. The oxidation of alcohol groups creates more binding sites by creating functional groups such as COO-, which increases chelation to metal ions. Fourier transform infrared spectroscopy confirms delignification of the peanut hulls by the disappearance of carboxyl peaks of the modified hulls, which were originally produced from the lignin content. Although, oxidation is not fully confirmed, it is not ruled out because the expected carboxylate peak (1680 cm-1) maybe overshadowed by a broad peak due to OH bending of water adsorbed to the hulls. Hulls adsorbed copper from solutions in the concentration range of 50-1000 ppm of CuCl2. Concentrations of pre- and post-adsorption solutions were determined using inductively coupled plasma optical emission spectroscopy. The adsorption isotherms were fit to known two and three-parameter models, evaluated and the binding mechanism was inferred. Maximum surface coverage was 3.5 +/- 0.6 mg Cu2+ /g hull for unmodified hulls and 11 +/- 1 mg Cu2+/g hull for modified hulls. The adsorption for the hulls is best described by the Langmuir model, suggesting monolayer, homogeneous adsorption. With a free energy of adsorption of 10.5 +/- 0.9 kJ/mol for unmodified hulls and 14.5 +/-0.4 kJ/mol for modified hulls, the process is categorized as chemisorption for both types of hulls. The adsorption for both hulls is also described by the Redlich-Peterson model, giving beta nearer to 1 than 0, which further suggests homogeneous adsorption described by the Langmuir model. After rinsing the hulls

  20. Patterns of binding of aluminum-containing adjuvants to Haemophilus influenzae type b and meningococcal group C conjugate vaccines and components.

    Science.gov (United States)

    Otto, Robert B D; Burkin, Karena; Amir, Saba Erum; Crane, Dennis T; Bolgiano, Barbara

    2015-09-01

    The basis of Haemophilus influenzae type b (Hib) and Neisseria meningitidis serogroup C (MenC) glycoconjugates binding to aluminum-containing adjuvants was studied. By measuring the amount of polysaccharide and protein in the non-adsorbed supernatant, the adjuvant, aluminum phosphate, AlPO4, was found to be less efficient than aluminum hydroxide, Al(OH)3 at binding to the conjugates, at concentrations relevant to licensed vaccine formulations and when equimolar. At neutral pH, binding of TT conjugates to AlPO4 was facilitated through the carrier protein, with only weak binding of AlPO4 to CRM197 being observed. There was slightly higher binding of either adjuvant to tetanus toxoid conjugates, than to CRM197 conjugates. This was verified in AlPO4 formulations containing DTwP-Hib, where the adsorption of TT-conjugated Hib was higher than CRM197-conjugated Hib. At neutral pH, the anionic Hib and MenC polysaccharides did not appreciably bind to AlPO4, but did bind to Al(OH)3, due to electrostatic interactions. Phosphate ions reduced the binding of the conjugates to the adjuvants. These patterns of adjuvant adsorption can form the basis for future formulation studies with individual and combination vaccines containing saccharide-protein conjugates. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  1. Patterns of binding of aluminum-containing adjuvants to Haemophilus influenzae type b and meningococcal group C conjugate vaccines and components

    Science.gov (United States)

    Otto, Robert B.D.; Burkin, Karena; Amir, Saba Erum; Crane, Dennis T.; Bolgiano, Barbara

    2015-01-01

    The basis of Haemophilus influenzae type b (Hib) and Neisseria meningitidis serogroup C (MenC) glycoconjugates binding to aluminum-containing adjuvants was studied. By measuring the amount of polysaccharide and protein in the non-adsorbed supernatant, the adjuvant, aluminum phosphate, AlPO4, was found to be less efficient than aluminum hydroxide, Al(OH)3 at binding to the conjugates, at concentrations relevant to licensed vaccine formulations and when equimolar. At neutral pH, binding of TT conjugates to AlPO4 was facilitated through the carrier protein, with only weak binding of AlPO4 to CRM197 being observed. There was slightly higher binding of either adjuvant to tetanus toxoid conjugates, than to CRM197 conjugates. This was verified in AlPO4 formulations containing DTwP–Hib, where the adsorption of TT-conjugated Hib was higher than CRM197-conjugated Hib. At neutral pH, the anionic Hib and MenC polysaccharides did not appreciably bind to AlPO4, but did bind to Al(OH)3, due to electrostatic interactions. Phosphate ions reduced the binding of the conjugates to the adjuvants. These patterns of adjuvant adsorption can form the basis for future formulation studies with individual and combination vaccines containing saccharide-protein conjugates. PMID:26194164

  2. Ultralow-loss CMOS copper plasmonic waveguides

    DEFF Research Database (Denmark)

    Fedyanin, Dmitry Yu.; Yakubovsky, Dmitry I.; Kirtaev, Roman V.

    2016-01-01

    with microelectronics manufacturing technologies. This prevents plasmonic components from integration with both silicon photonics and silicon microelectronics. Here, we demonstrate ultralow-loss copper plasmonic waveguides fabricated in a simple complementary metal-oxide semiconductor (CMOS) compatible process, which...

  3. Brazing copper to dispersion-strengthened copper

    Energy Technology Data Exchange (ETDEWEB)

    Ryding, D.G.; Allen, D.; Lee, R.

    1996-08-01

    The Advanced Photon Source (APS) is a state-of-the-art synchrotron light source that will produce intense x-ray beams, which will allow the study of smaller samples and faster reactions and processes at a greater level of detail that has been possible to date. The beam is produced by using third-generation insertion devices in a 7 GeV electron/positron storage ring that is 1100 meters in circumference. The heat load from these intense high power devices is very high and certain components must sustain total heat loads of 3 to 15 kW and heat fluxes of 30 W/mm{sup 2}. Because the beams will cycle on and off many times, thermal shock and fatigue will be a problem. High heat flux impinging on a small area causes a large thermal gradient that results in high stress. GlidCop{reg_sign}, a dispersion strengthened copper, is the desired material because of its high thermal conductivity and superior mechanical properties as compared to copper and its alloys. GlidCop is not amenable to joining by fusion welding, and brazing requires diligence because of high diffusivity. Brazing procedures were developed using optical and scanning electron microscopy.

  4. Copper Test

    Science.gov (United States)

    ... and Iron-binding Capacity (TIBC, UIBC) Trichomonas Testing Triglycerides Troponin Tryptase Tumor Markers Uric Acid Urinalysis Urine ... play a role in the regulation of iron metabolism , formation of connective tissue , energy production at the ...

  5. Use of copper radioisotopes in investigating disorders of copper metabolism

    International Nuclear Information System (INIS)

    Camakaris, J.; Voskoboinik, I.; Brooks, H.; Greenough, M.; Smith, S.; Mercer, J.

    1998-01-01

    Full text: Copper is an essential trace element for life as a number of vital enzymes require it. Copper deficiency can lead to neurological disorders, osteoporosis and weakening of arteries. However Cu is also highly toxic and homeostatic mechanisms have evolved to maintain Cu at levels which satisfy requirements but do not cause toxicity. Toxicity is mediated by the oxidative capacity of Cu and its ability to generate toxic free radicals. There are several acquired and inherited diseases due to either Cu toxicity or Cu deficiency. The study of these diseases facilitates identification of genes and proteins involved in copper homeostasis, and this in turn will provide rational therapeutic approaches. Our studies have focused on Menkes disease in humans which is an inherited and usually lethal copper deficiency. Using copper radioisotopes 64 Cu (t 1/2 = 12.8 hr) and 67 Cu (t 1/2 = 61 hr) we have studied the protein which is mutated in Menkes disease. This is a transmembrane copper pump which is responsible for absorption of copper into the body and also functions to pump out excess Cu from cells when Cu is elevated. It is therefore a vital component of normal Cu homeostasis. We have provided the first biochemical evidence that the Menkes protein functions as a P-type ATPase Cu pump (Voskoboinik et al., FEBS Letters, in press) and these data will be discussed. The assay involved pumping of radiocopper into purified membrane vesicles. Furthermore we have transfected normal and mutant Menkes genes into cells and are carrying out structure-function studies. We are also studying the role of amyloid precursor protein (APP) as a Cu transport protein in order to determine how Cu regulates this protein and its cleavage products. These studies will provide vital information on the relationship between Cu and APP and processes which lead to Alzheimers disease

  6. Mixed-ligand binuclear copper(II) complex of 5 ...

    Indian Academy of Sciences (India)

    ligand binuclear copper(II) complex of 5-methylsalicylaldehyde and 2,2 -bipyridyl: Synthesis, crystal structure, DNA binding and nuclease activity. PERUMAL GURUMOORTHYa, JAYARAM RAVICHANDRANa,b and AZIZ KALILUR RAHIMANa,∗.

  7. The Yin and Yang of Copper During Infection

    Science.gov (United States)

    Besold, Angelique N.; Culbertson, Edward M.; Culotta, Valeria C.

    2017-01-01

    Copper is an essential micronutrient for both pathogens and the animal hosts they infect. However, copper can also be toxic in cells due to its redox properties and ability to disrupt active sites of metalloproteins, such as Fe-S enzymes. Through these toxic properties, copper is an effective antimicrobial agent and an emerging concept in innate immunity is that the animal host intentionally exploits copper toxicity in antimicrobial weaponry. In particular, macrophages can attack invading microbes with high copper and this metal is also elevated at sites of lung infection. In addition, copper levels in serum rise during infection with a wide array of pathogens. To defend against this toxic copper, the microbial intruder is equipped with a battery of copper detoxification defenses that promote survival in the host, including copper exporting ATPases and copper binding metallothioneins. However, it is important to remember that copper is also an essential nutrient for microbial pathogens and serves as important cofactor for enzymes such as cytochrome c oxidase for respiration, superoxide dismutase for anti-oxidant defense and multi-copper oxidases that act on metals and organic substrates. We therefore posit that the animal host can also thwart pathogen growth by limiting their copper nutrients, similar to the well-documented nutritional immunity effects for starving microbes of essential zinc, manganese and iron micronutrients. This review provides both sides of the copper story and evaluates how the host can exploit either copper-the-toxin or copper-the-nutrient in antimicrobial tactics at the host-pathogen battleground.  PMID:26790881

  8. Separation of copper-64 from copper phthalocyanine

    International Nuclear Information System (INIS)

    Battaglin, R.I.M.

    1979-01-01

    The separation of copper-64 from irradiated copper phthalocyanine by Szilard-Chalmers effect is studied. Two methods of separation are used: one of them is based on the dissolution of the irradiated dry compound in concentrated sulfuric acid following its precipitation in water. In the other one the compound is irradiated with water in paste form following treatment with water and hydrochloric acid. The influence of the crystal form of the copper phthalocyanine on the separation yield of copper-64 is shown. Preliminary tests using the ionic exchange technique for purification and changing of copper-64 sulfate to chloride form are carried out. The specific activity using the spectrophotometric technique, after the determination of the copper concentration in solution of copper-64, is calculated. (Author) [pt

  9. Effects of organic matters coming from Chinese tea on soluble copper release from copper teapot

    International Nuclear Information System (INIS)

    Ni Lixiao; Li Shiyin

    2008-01-01

    The morphology and elemental composition of the corrosion products of copper teapot's inner-surface were characterized by the scanning electron microscopy and energy dispersive X-ray surface analysis (SEM/EDS), X-ray powder diffraction (XRD) and X-ray photon spectroscopy (XPS) analysis. It was revealed that Cu, Fe, Ca, P, Si and Al were the main elements of corrosion by-products, and the α-SiO 2 , Cu 2 O and CaCO 3 as the main mineral components on the inner-surface of copper teapot. The effects of organic matters coming from Chinese tea on soluble copper release from copper teapots in tap water were also investigated. The results showed that the doses of organic matter (as TOC), temperate and stagnation time have significant effects on the concentration of soluble copper released from copper teapots in tap water

  10. Copper in plants

    OpenAIRE

    Yruela, Inmaculada

    2005-01-01

    Copper is an essential metal for normal plant growth and development, although it is also potentially toxic. Copper participates in numerous physiological processes and is an essential cofactor for many metalloproteins, however, problems arise when excess copper is present in cells. Excess copper inhibits plant growth and impairs important cellular processes (i.e., photosynthetic electron transport). Since copper is both an essential cofactor and a toxic element, involving a complex network o...

  11. Simultaneous Platinum and Copper Ion Attachment to a Human Copper Chaperone Protein

    Science.gov (United States)

    Hodak, Miroslav; Cvitkovic, John; Yu, Corey; Dmitriev, Oleg; Kaminski, George; Bernholc, Jerry

    2015-03-01

    Cisplatin is a potent anti-cancer drug based on a platinum ion. However, its effectiveness is decreased by cellular resistance, which involves cisplatin attaching to copper transport proteins. One of such proteins is Atox1, where cisplatin attaches to the copper binding site. Surprisingly, it was shown that both cisplatin and copper can attach to Atox1 at the same time. To study this double metal ion attachment, we use the KS/FD DFT method, which combines Kohn-Sham DFT with frozen-density DFT to achieve efficient quantum-mechanical description of explicit solvent. Calculations have so far investigated copper ion attachment to CXXC motifs present in Atox1. The addition of the platinum ion and the competition between the two metals is currently being studied. These calculations start from a molecular mechanics (MM) structural model, in which glutathione groups provide additional ligands to the Pt ion. Our goals are to identify possible Cu-Pt structures and to determine whether copper/platinum attachment is competitive, independent, or cooperative. Results will be compared to the 1H, N1 5 -HSQC NMR experiments, in which binding of copper and cisplatin to Atox1 produces distinct secondary chemical shift signatures, allowing for kinetic studies of simultaneous metal binding.

  12. How Do the Different Components of Episodic Memory Develop? Role of Executive Functions and Short-Term Feature-Binding Abilities

    Science.gov (United States)

    Picard, Laurence; Cousin, Sidonie; Guillery-Girard, Berenere; Eustache, Francis; Piolino, Pascale

    2012-01-01

    This study investigated the development of all 3 components of episodic memory (EM), as defined by Tulving, namely, core factual content, spatial context, and temporal context. To this end, a novel, ecologically valid test was administered to 109 participants aged 4-16 years. Results showed that each EM component develops at a different rate.…

  13. Cyclic AMP-binding capacities and histone kinase activation in subcellular components of neocortical tissue. Differential responses to three neurohumoural agents

    Science.gov (United States)

    Patel, Jitendra; Newman, Michael; McIlwain, Henry

    1981-01-01

    1. Noradrenaline and histamine, when added to superfused guinea-pig cerebral-cortical tissues, increased both cyclic AMP-dependent and -independent histone kinase activities of some, but not of all, subsequently isolated subcellular fractions, and decreased their cyclic [3H]AMP-binding capacity, which was concluded to be due to an increase in endogenously bound cyclic AMP. 2. Adenosine and 2-chloroadenosine also diminished the cyclic [3H]AMP-binding capacities, but did not affect the histone kinase activities. 3. DEAE-cellulose chromatography and stability to KCl additions showed that the greater part of the histone kinase of the present preparations corresponded to the type II enzyme [of Corbin, Keely & Park (1975) J. Biol. Chem. 250, 218–225], with a lesser amount of type I activity. Different sites of cyclic AMP accumulation in relation to these or other kinases are considered in interpreting the differential tissue responses to the neurohumoural agents examined. PMID:6118136

  14. Purification, subunit characterization and ultrastructure of three soluble bovine lectins: conglutinin, mannose-binding protein and the pentraxin serum amyloid P-component

    DEFF Research Database (Denmark)

    Andersen, Ove; Friis, P; Holm Nielsen, E

    1992-01-01

    affinity chromatography and selective elution was developed. The purification was monitored by SDS-PAGE, Western blotting and electron microscopy. Binding of the lectins to Sephadex-iC3b, their collagenase sensitivity, and the size and antibody reactivity of their subunits was investigated....... The demonstration, by SDS-PAGE, of 25-kDa subunits, which were unaffected by collagenase treatment but bound to Sephadex-iC3b and antibodies to human SAP, indicated the existence of bovine SAP. Bovine conglutinin (BK) also showed calcium-dependent binding to Sephadex-iC3b, whereas bovine MBP did not. The binding...... of BK was inhibitable with GlcNAc. A 3000-fold increase in BK activity (ELISA) was obtained in eluates from Sephadex-iC3b. SDS-PAGE analyses of BK and MBP revealed subunits with an Mr of 43 kDa and 30 kDa, respectively. These subunits were sensitive to collagenase treatment which reduced the Mr to 20 k...

  15. Zc3h13/Flacc is required for adenosine methylation by bridging the mRNA-binding factor Rbm15/Spenito to the m6A machinery component Wtap/Fl(2)d.

    Science.gov (United States)

    Knuckles, Philip; Lence, Tina; Haussmann, Irmgard U; Jacob, Dominik; Kreim, Nastasja; Carl, Sarah H; Masiello, Irene; Hares, Tina; Villaseñor, Rodrigo; Hess, Daniel; Andrade-Navarro, Miguel A; Biggiogera, Marco; Helm, Mark; Soller, Matthias; Bühler, Marc; Roignant, Jean-Yves

    2018-03-01

    N 6 -methyladenosine (m 6 A) is the most abundant mRNA modification in eukaryotes, playing crucial roles in multiple biological processes. m 6 A is catalyzed by the activity of methyltransferase-like 3 (Mettl3), which depends on additional proteins whose precise functions remain poorly understood. Here we identified Zc3h13 (zinc finger CCCH domain-containing protein 13)/Flacc [Fl(2)d-associated complex component] as a novel interactor of m 6 A methyltransferase complex components in Drosophila and mice. Like other components of this complex, Flacc controls m 6 A levels and is involved in sex determination in Drosophila We demonstrate that Flacc promotes m 6 A deposition by bridging Fl(2)d to the mRNA-binding factor Nito. Altogether, our work advances the molecular understanding of conservation and regulation of the m 6 A machinery. © 2018 Knuckles et al.; Published by Cold Spring Harbor Laboratory Press.

  16. Theoretical study of geometry dependent I-V characteristics of copper and gold quantum point contacts

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadzadeh, Saeideh [Center of Microtechnologies, Chemnitz University of Technology, Chemnitz (Germany); Streiter, Reinhard; Gessner, Thomas [Center of Microtechnologies, Chemnitz University of Technology, Chemnitz (Germany); Fraunhofer Research Institution for Electronic Nano Systems, ENAS, Chemnitz (Germany)

    2009-07-01

    Quantum point contacts have attracted significant attention with continuing miniaturization of nanoscale electronic components for the two past decades. In present work, we study the electronic transport properties of copper and gold quantum point contacts using the non-equilibrium Green's function technique on the density functional tight binding method for modelling the geometry dependent I-V characteristics. The copper and gold quantum point contacts are sandwiched between cognate (001) electrodes and the electronic current is deduced according to the Landauer formulation to study the effect of the quantum point contact length scales and geometry defects on the electronic transport properties. The transmission coefficients, conductance and the voltage drop characteristics are calculated as well.

  17. Aquatic Life Criteria - Copper

    Science.gov (United States)

    Documents pertain to Aquatic Life Ambient Water Quality criteria for Copper (2007 Freshwater, 2016 Estuarine/marine). These documents contain the safe levels of Copper in water that should protect to the majority of species.

  18. Antwerp Copper Plates

    DEFF Research Database (Denmark)

    Wadum, Jørgen

    1999-01-01

    In addition to presenting a short history of copper paintings, topics detail artists’ materials and techniques, as well as aspects of the copper industry, including mining, preparation and trade routes....

  19. Using Xas And Sxrf to Study Copper in Wilson Disease at the Molecular And Tissue Level

    Energy Technology Data Exchange (ETDEWEB)

    Ralle, M.; Blackburn, N.J.; Lutsenko, S.

    2009-06-05

    Wilson disease (WD) is a genetic disorder of copper metabolism associated with severe hepatic, neurological, and psychiatric abnormalities. In WD, the billiary copper excretion is impaired and copper accumulates in tissues, particularly in the liver and the brain. The affected gene, ATP7B, encodes the copper transporting ATPase, Wilson disease protein (WNDP). WNDP has six copper binding sites in the N-terminal portion of the molecule. Each site includes the conserved amino acid sequence MXCXXC, and binds 1 Cu(I) through its 2 cysteine residues. We performed X-ray absorption studies at the Cu K{sub {alpha}}-edge on the recombinant N-terminal domain of WNDP (N-WNDP). Copper was bound to N-WNDP either in vivo or in vitro in the presence of different reducing agents. We found that in N-WNDP copper is predominantly coordinated in a linear fashion by two cysteines, with the appearance of a Cu-Cu interaction when all metal binding sites are filled. Increasing amounts of reducing agents containing sulfide or phosphine groups led to binding of the exogenous ligands to copper thereby increasing the coordination number of copper from two to three. To better understand the role of copper in WD, we utilized livers of the 6-weeks-old Atp7b-/- mice (an animal model for WD) in which the copper concentration was 10--20-fold higher compared to that of the control mice. The distribution of copper in hepatocytes was evaluated by synchrotron based X-ray fluorescence microprobe (SXRF). We demonstrate that we can prepare liver slices that retain copper and can detect copper with subcellular resolution. On the same sections {mu}-XANES (spot size: 5 micron) was used to determine the oxidation state of copper.

  20. Using XAS and SXRF to Study Copper in Wilson Disease at the Molecular and Tissue Level

    Science.gov (United States)

    Ralle, Martina; Blackburn, Ninian J.; Lutsenko, Svetlana

    2007-02-01

    Wilson disease (WD) is a genetic disorder of copper metabolism associated with severe hepatic, neurological, and psychiatric abnormalities. In WD, the billiary copper excretion is impaired and copper accumulates in tissues, particularly in the liver and the brain. The affected gene, ATP7B, encodes the copper transporting ATPase, Wilson disease protein (WNDP). WNDP has six copper binding sites in the N-terminal portion of the molecule. Each site includes the conserved amino acid sequence MXCXXC, and binds 1 Cu(I) through its 2 cysteine residues. We performed X-ray absorption studies at the Cu Kα-edge on the recombinant N-terminal domain of WNDP (N-WNDP). Copper was bound to N-WNDP either in vivo or in vitro in the presence of different reducing agents. We found that in N-WNDP copper is predominantly coordinated in a linear fashion by two cysteines, with the appearance of a Cu-Cu interaction when all metal binding sites are filled. Increasing amounts of reducing agents containing sulfide or phosphine groups led to binding of the exogenous ligands to copper thereby increasing the coordination number of copper from two to three. To better understand the role of copper in WD, we utilized livers of the 6-weeks-old Atp7b-/- mice (an animal model for WD) in which the copper concentration was 10-20-fold higher compared to that of the control mice. The distribution of copper in hepatocytes was evaluated by synchrotron based X-ray fluorescence microprobe (SXRF). We demonstrate that we can prepare liver slices that retain copper and can detect copper with subcellular resolution. On the same sections μ-XANES (spot size: 5 micron) was used to determine the oxidation state of copper.

  1. Demystifying Controlling Copper Corrosion

    Science.gov (United States)

    The LCR systematically misses the highest health and corrosion risk sites for copper. Additionally, there are growing concerns for WWTP copper in sludges and discharge levels. There are many corrosion control differences between copper and lead. This talk explains the sometimes c...

  2. Heterocomplexes of Mannose-binding Lectin and the Pentraxins PTX3 or Serum Amyloid P Component Trigger Cross-activation of the Complement System

    DEFF Research Database (Denmark)

    Ma, Y. J.; Doni, A.; Skjoedt, M.-o.

    2011-01-01

    The long pentraxin 3 (PTX3), serum amyloid P component (SAP), and C-reactive protein belong to the pentraxin family of pattern recognition molecules involved in tissue homeostasis and innate immunity. They interact with C1q from the classical complement pathway. Whether this also occurs via...... complement pathways via recruitment of C1q, whereas SAP-enhanced complement activation occurs via a hitherto unknown mechanism. Taken together, MBL-pentraxin heterocomplexes trigger cross-activation of the complement system....

  3. Copper isotope fractionation by desert shrubs

    International Nuclear Information System (INIS)

    Navarrete, Jesica U.; Viveros, Marian; Ellzey, Joanne T.; Borrok, David M.

    2011-01-01

    Copper has two naturally occurring stable isotopes of masses 63 and 65 which can undergo mass dependent fractionation during various biotic and abiotic chemical reactions. These interactions and their resulting Cu isotope fractionations can be used to determine the mechanisms involved in the cycling of Cu in natural systems. In this study, Cu isotope changes were investigated at the organismal level in the metal-accumulating desert plant, Prosopis pubescens. Initial results suggest that the lighter Cu isotope was preferentially incorporated into the leaves of the plant, which may suggest that Cu was actively transported via intracellular proteins. The roots and stems show a smaller degree of Cu isotope fractionation and the direction and magnitude of the fractionations was dependent upon the levels of Cu exposure. Based on this and previous work with bacteria and yeast, a trend is emerging that suggests the lighter Cu isotope is preferentially incorporated into biological components, while the heavier Cu isotope tends to become enriched in aqueous solutions. In bacteria, plants and animals, intracellular Cu concentrations are strictly regulated via dozens of enzymes that can bind, transport, and store Cu. Many of these enzymes reduce Cu(II) to Cu(I). These initial results seem to fit into a broader picture of Cu isotope cycling in natural systems where oxidation/reduction reactions are fundamental in controlling the distributions of Cu isotopes.

  4. Energetics of copper trafficking between the Atx1 metallochaperone and the intracellular copper transporter, Ccc2.

    Science.gov (United States)

    Huffman, D L; O'Halloran, T V

    2000-06-23

    The Atx1 metallochaperone protein is a cytoplasmic Cu(I) receptor that functions in intracellular copper trafficking pathways in plants, microbes, and humans. A key physiological partner of the Saccharomyces cerevisiae Atx1 is Ccc2, a cation transporting P-type ATPase located in secretory vesicles. Here, we show that Atx1 donates its metal ion cargo to the first N-terminal Atx1-like domain of Ccc2 in a direct and reversible manner. The thermodynamic gradient for metal transfer is shallow (K(exchange) = 1.4 +/- 0.2), establishing that vectorial delivery of copper by Atx1 is not based on a higher copper affinity of the target domain. Instead, Atx1 allows rapid metal transfer to its partner. This equilibrium is unaffected by a 50-fold excess of the Cu(I) competitor, glutathione, indicating that Atx1 also protects Cu(I) from nonspecific reactions. Mechanistically, we propose that a low activation barrier for transfer between partners results from complementary electrostatic forces that ultimately orient the metal-binding loops of Atx1 and Ccc2 for formation of copper-bridged intermediates. These thermodynamic and kinetic considerations suggest that copper trafficking proteins overcome the extraordinary copper chelation capacity of the eukaryotic cytoplasm by catalyzing the rate of copper transfer between physiological partners. In this sense, metallochaperones work like enzymes, carefully tailoring energetic barriers along specific reaction pathways but not others.

  5. A plant small polypeptide is a novel component of DNA-binding protein phosphatase 1-mediated resistance to plum pox virus in Arabidopsis.

    Science.gov (United States)

    Castelló, María José; Carrasco, Jose Luis; Navarrete-Gómez, Marisa; Daniel, Jacques; Granot, David; Vera, Pablo

    2011-12-01

    DNA-binding protein phosphatases (DBPs) have been identified as a novel class of plant-specific regulatory factors playing a role in plant-virus interactions. NtDBP1 from tobacco (Nicotiana tabacum) was shown to participate in transcriptional regulation of gene expression in response to virus infection in compatible interactions, and AtDBP1, its closest relative in the model plant Arabidopsis (Arabidopsis thaliana), has recently been found to mediate susceptibility to potyvirus, one of the most speciose taxa of plant viruses. Here, we report on the identification of a novel family of highly conserved small polypeptides that interact with DBP1 proteins both in tobacco and Arabidopsis, which we have designated DBP-interacting protein 2 (DIP2). The interaction of AtDIP2 with AtDBP1 was demonstrated in vivo by bimolecular fluorescence complementation, and AtDIP2 was shown to functionally interfere with AtDBP1 in yeast. Furthermore, reducing AtDIP2 gene expression leads to increased susceptibility to the potyvirus Plum pox virus and to a lesser extent also to Turnip mosaic virus, whereas overexpression results in enhanced resistance. Therefore, we describe a novel family of conserved small polypeptides in plants and identify AtDIP2 as a novel host factor contributing to resistance to potyvirus in Arabidopsis.

  6. IgE-binding components of cultured human keratinocytes in atopic eczema/dermatitis syndrome and their crossreactivity with Malassezia furfur.

    Science.gov (United States)

    Kortekangas-Savolainen, O; Peltonen, S; Pummi, K; Kalimo, K; Savolainen, J

    2004-02-01

    Atopic eczema/dermatitis syndrome (AEDS) patients display immunoglobulin E (IgE) reactivity to several antigens, e.g. saprophytic yeasts as Malassezia furfur. AEDS patients also show IgE autoreactivity towards cells of their own tissue including epidermis. The aim of this study was to investigate the IgE autoreactivity of AEDS patients to cultured keratinocytes and to reveal potential crossreacting epitopes in cultured keratinocytes and M. furfur. Serum samples of 27 AEDS patients were analyzed, of these 13 were M. furfur radioallergosorbent test (RAST) positive and 14 negative. Four urticaria, three psoriasis, and seven nonatopic patients were included as controls. The studies were performed by using IgE immunoblotting and immunoblotting inhibition methods. Ten IgE-binding protein bands were detected in cultured human keratinocytes by IgE immunoblotting using sera from adult AEDS patients. Anti-keratinocyte IgE antibodies were more associated with elevated S-IgE level than M. furfur RAST. Clear crossreactivity with M. furfur could not be shown. The possible pathomechanism of anti-keratinocyte IgE antibodies is not due to IgE epitope mimicry of saprophytic yeast and local tissue in AEDS skin.

  7. Engineering of blood vessel patterns by angio-morphogens [angiotropins]: non-mitogenic copper-ribonucleoprotein cytokins [CuRNP ribokines] with their metalloregulated constituents of RAGE-binding S100-EF-hand proteins and extracellular RNA bioaptamers in vascular remodeling of tissue and angiogenesis in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Wissler, J.H. [ARCONS Applied Research, Bad Nauheim (Germany)

    2001-12-01

    Tissue vascularization is requisite to successful cell-based therapies, biomaterial design and implant integration. Thus, known problems in ossointegration of avascular implants in connection with the generation of bone tissue reflect arrays of general problems of socio-economic relevance existing in reparative medicine still waiting for to be solved. For this purpose, morphogenesis and remodeling of endothelial angio-architectures in tissue and in vitro by isolated non-mitogenic angio-morphogens [angiotropins] are considered in terms of their structure, function and action mechanisms. Extracellular angiotropins are secreted by activated leukocytes/monocytes/macrophages. They are a family of cytokines with morphogen bioactivity selectively directed to endothelial cells. Their structure was deciphered as metalloregulated copper-ribonucleoproteins [CuRNP ribokines]. They are built up of angiotropin-related S100-EF-hand protein [ARP] and highly modified and edited 5'end-phosphorylated RNA [ARNA], complexed together by copper ions. Oxidant-sensitive ARNA and their precursors represent novel types in a RNA world: They are the first isolated and sequenced forms of extracellular RNA [eRNA], may act as cytokine and bioaptamer, contain isoguanosine [crotonoside] as modified nucleoside and show up copper as RNA-structuring transition metal ion. By metalloregulated bioaptamer functions, ARNA impart novel biofunctions to RAGE-binding S100-EF-hand proteins. Angiotropin morphogens were shown suitable for neointiation and remodeling of blood vessel patterns in different, adult, embryonal and artificial tissues. These neovascular patterns manifest regulated hemodynamics for preventing tissue necrosis, supporting tissue functions and promoting wound healing. As evaluated in skin and muscle vascularization, the neovascular patterns are integrated into homeostatic control mechanisms of tissue. Thus, the morphogens show up beneficial perspectives and are suggested useful tools

  8. Controlling Copper Electrochemical Deposition (ECD)

    Science.gov (United States)

    West, Michael; McDonald, Robert; Anderson, Marc; Kingston, Skip; Mui, Rudy

    2003-09-01

    The implementation of copper processing in semiconductor manufacturing has resulted in major process development and manufacturing challenges. A fundamental understanding of the copper plating processes used in manufacturing has been limited by the lack of in-line methods for direct measurement and control of process chemistry. Plating bath chemistry adjustments and change-out frequencies are currently determined using a combination of indirect electrochemical monitoring techniques, off-line analyses of wafer metrology and analytical lab measurements. There have been a number of industry reports of major process startup delays, yield management problems and reliability issues as a result of these difficulties. A new in-process mass spectrometry (IPMS) approach enables automated, real-time measurement of both the inorganic components and organic additives in the copper electroplating chemistry as they change during production. The tool is not only capable of real time direct quantification of the copper, chloride, pH, and organic additives in the plating bath, but can also monitor additive breakdown byproducts as they occur during the production process. These breakdown products, as well as changes in the original bath constituent composition can be expected to have a major impact on process performance. We are now in the process of measuring longer term plating bath stability and chemistry changes in prototype applications in semiconductor fab manufacturing environments. The first results demonstrate improved process understanding and the potential for greatly improved process control. We will discuss the technical challenges that were successfully addressed in developing the IPMS capability for application to the copper plating process and the initial process data subsequently obtained.

  9. Development of copper bromide laser master oscillator power ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Development of master oscillator power amplifier (MOPA) system of copper bromide laser (CBL) operating at 110 W average power is reported. The spectral distribution of power at green (510.6 nm) and yellow (578.2 nm) components in the output of a copper bromide laser is studied as a function of ...

  10. Development of copper bromide laser master oscillator power

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Development of master oscillator power amplifier (MOPA) system of copper bromide laser (CBL) operating at 110 W average power is reported. The spectral distribution of power at green (510.6 nm) and yellow (578.2 nm) components in the output of a copper bromide laser is studied as a function of ...

  11. Development of copper bromide laser master oscillator power ...

    Indian Academy of Sciences (India)

    2014-02-09

    Feb 9, 2014 ... Abstract. Development of master oscillator power amplifier (MOPA) system of copper bromide laser (CBL) operating at 110 W average power is reported. The spectral distribution of power at green (510.6 nm) and yellow (578.2 nm) components in the output of a copper bromide laser is studied as a function ...

  12. Substrate-Linked Conformational Change in the Periplasmic Component of a Cu(I)/Ag(I) Efflux System

    Energy Technology Data Exchange (ETDEWEB)

    Bagai, I.; Liu, W.; Rensing, C.; Blackburn, N.J.; McEvoy, M.M.

    2009-06-02

    Gram-negative bacteria utilize dual membrane resistance nodulation division-type efflux systems to export a variety of substrates. These systems contain an essential periplasmic component that is important for assembly of the protein complex. We show here that the periplasmic protein CusB from the Cus copper/silver efflux system has a critical role in Cu(I) and Ag(I) binding. Isothermal titration calorimetry experiments demonstrate that one Ag(I) ion is bound per CusB molecule with high affinity. X-ray absorption spectroscopy data indicate that the metal environment is an all-sulfur 3-coordinate environment. Candidates for the metal-coordinating residues were identified from sequence analysis, which showed four conserved methionine residues. Mutations of three of these methionine residues to isoleucine resulted in significant effects on CusB metal binding in vitro. Cells containing these CusB variants also show a decrease in their ability to grow on copper-containing plates, indicating an important functional role for metal binding by CusB. Gel filtration chromatography demonstrates that upon binding metal, CusB undergoes a conformational change to a more compact structure. Based on these structural and functional effects of metal binding, we propose that the periplasmic component of resistance nodulation division-type efflux systems plays an active role in export through substrate-linked conformational changes.

  13. EPR studies of cooperative binding of Cu (II) to hemoglobin

    International Nuclear Information System (INIS)

    Louro, S.R.W.; Tabak, M.

    1983-07-01

    The investigation of the relative affinities of the two pairs of hemoglobin copper sites by monitoring the EPR spectra of the complexes formed by the reaction of copper with deoxyhemoglobin is reported. A model in which two sites are assumed to accept copper ions in a noncooperative way is not able to predict the experimental results. Thus it is conclude that the binding of these ions to hemoglobin is a cooperative phenomenon. (Author) [pt

  14. V-shaped ligand 1,3-bis(1-ethylbenzimidazol-2-yl)-2-thiapropane and manganese(II), cobalt(II) and copper(II) complexes: Synthesis, crystal structure, DNA-binding properties and antioxidant activities.

    Science.gov (United States)

    Wu, Huilu; Yang, Zaihui; Wang, Fei; Peng, Hongping; Zhang, Han; Wang, Cuiping; Wang, Kaitong

    2015-07-01

    A V-shaped ligand 1,3-bis(1-ethylbenzimidazol-2-yl)-2-thiapropane (bebt) and its transition metal complexes, [Mn(bebt)(pic)2]·CH3OH (pic=picrate) 1, [Co(bebt)2](pic)22 and [Cu(bebt)2](pic)2·2DMF 3, have been synthesized and characterized. The coordinate forms of complexes 1 and 2 are basically alike, which can be described as six-coordinated distorted octahedron. The geometric structure around Cu(II) atom can be described as distorted tetrahedral in complex 3. The DNA-binding properties of the ligand bebt and complexes have been investigated by electronic absorption, fluorescence, and viscosity measurements. The results suggest that bebt and complexes bind to DNA via an intercalative binding mode and the order of the binding affinity is 1DNA-binding properties are also discussed. Moreover, the complex 3 possess significant antioxidant activity against superoxide and hydroxyl radicals, and the scavenging effects of it are stronger than standard mannitol and vitamin C. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Activation of chick tendon lysyl oxidase in response to dietary copper.

    Science.gov (United States)

    Rucker, R B; Rucker, B R; Mitchell, A E; Cui, C T; Clegg, M; Kosonen, T; Uriu-Adams, J Y; Tchaparian, E H; Fishman, M; Keen, C L

    1999-12-01

    Lysyl oxidase (EC 1.4.3.13), a cuproenzyme, can account for 10-30% of the copper present in connective tissue. Herein, we assess the extent to which tissue copper concentrations and lysyl oxidase activity are related because the functional activity of lysyl oxidase and the copper content of chick tendon are both related to dietary copper intake. Chicks (1-d old) were fed diets (basal copper concentration, 0.4 microg/g diet) to which copper was added from 0 to 16 microg/g diet. Liver and plasma copper levels tended to normalize in chickens that consumed from 1 to 4 microg copper/g of diet, whereas tendon copper concentrations suggested an unusual accumulation of copper in chickens that consumed 16 microg copper/g diet. The molecular weight of lysyl oxidase was also estimated using matrix-assisted laser desorption ionization/time-of-flight/mass spectrometry (MALDI/TOF/MS). A novel aspect of these measurements was estimation of protein mass directly from the surface of chick tendons and aortae. Whether copper deficiency (0 added copper) or copper supplementation (16 microg copper/g of diet) caused changes in the molecular weight of protein(s) in tendon corresponding to lysyl oxidase was addressed. The average molecular weight of the peak corresponding to lysyl oxidase in tendon and aorta from copper-deficient birds was 28,386 Da +/- 86, whereas the average molecular weight of corresponding protein in tendon from copper-supplemented birds was 28,639 Da +/- 122. We propose that the shift in molecular weight is due in part to copper binding and the formation of lysyl tyrosyl quinone, the cofactor at the active site of lysyl oxidase.

  16. Final report on characterization of physical and mechanical properties of copper and copper alloys before and after irradiation

    DEFF Research Database (Denmark)

    Singh, B.N.; Tähtinen, S.

    2002-01-01

    The present report summarizes and highlights the main results of the work carried out during the last 5-6 years on effects of neutron irradiation on physical and mechanical properties of copper and copper alloys. The work was an European contribution toITER Research and Development programme...... the suitability of a copper alloy for its use in the first wall and divertor components of ITER. It is pointed out that the present work has managed onlyto identify some of the critical problems and limitations of the copper alloys for their employment in the hostile environment of 14 MeV neutrons. A considerable...

  17. Developing radiopure copper alloys for high strength low background applications

    Science.gov (United States)

    Suriano, A. M.; Howard, S. M.; Christofferson, C. D.; Arnquist, I. J.; Hoppe, E. W.

    2018-01-01

    High purity copper continues to play an important role for ultra-low-background detectors. Measurements of rare nuclear decays, e.g. neutrinoless double-beta decay, and searches for dark matter can require construction materials that have high thermal and electrical conductivity with bulk radiopurity less than one micro-Becquerel per kilogram. However, experiments currently using components constructed of radiopure electroformed copper struggle with design of structural and mechanical parts due to the physical properties of pure copper. A higher strength material which possesses many of the favorable attributes of copper yet remains radiopure is desired. A number of copper alloying candidates which may provide improved mechanical performance and adequate radiopurity were considered. Development of an electrodeposited copper-chrome alloy from additive-free electrolyte systems is discussed. The resulting material is shown to possess high strength and meets the aforementioned radiopurity goals.

  18. The structural analysis of the pro-oxidant copper-binding site of denatured apo-H43R SOD1 and the elucidation of the origin of the acquisition of the pro-oxidant activity.

    Science.gov (United States)

    Fujimaki, Nobuhiro; Miura, Takashi; Nakabayashi, Takakazu

    2016-02-14

    The pathogenesis of amyotrophic lateral sclerosis (ALS) is associated with mutations of Cu,Zn-superoxide dismutase (SOD1), which is a representative antioxidant enzyme. A previous study showed that the denatured apo-form of an ALS-linked mutant of human SOD1, His43 → Arg (H43R), obtains pro-oxidant activity as the reverse behavior of the native antioxidant activity by rebinding Cu(2+), which is considered to be closely related to the development of ALS. The Cu(2+)-binding site in denatured apo-H43R can be regarded as the center of the pro-oxidant activity, causing cellular oxidative stress. In the present study, the structure of the Cu(2+)-binding site of denatured apo-H43R was investigated to clarify the mechanism of the acquisition of the pro-oxidant activity. His residues constructing the Cu(2+)-binding site in denatured apo-H43R were experimentally assigned by absorption and fluorescence-based assays of SOD1 mutants, in which each of the seven His residues in H43R SOD1 is replaced with Ala. It was found that His120 is not involved with the Cu(2+)-binding site after denaturation, although the other His residues constructing the metal-binding site remain constant after denaturation. The disappearance of His120 from the Cu(2+)-binding site is therefore considered to be one of the important factors in obtaining the pro-oxidant activity. The mechanism of the acquisition of the pro-oxidant activity is discussed based on the results obtained.

  19. Inspection of disposal canisters components

    International Nuclear Information System (INIS)

    Pitkaenen, J.

    2013-12-01

    This report presents the inspection techniques of disposal canister components. Manufacturing methods and a description of the defects related to different manufacturing methods are described briefly. The defect types form a basis for the design of non-destructive testing because the defect types, which occur in the inspected components, affect to choice of inspection methods. The canister components are to nodular cast iron insert, steel lid, lid screw, metal gasket, copper tube with integrated or separate bottom, and copper lid. The inspection of copper material is challenging due to the anisotropic properties of the material and local changes in the grain size of the copper material. The cast iron insert has some acoustical material property variation (attenuation, velocity changes, scattering properties), which make the ultrasonic inspection demanding from calibration point of view. Mainly three different methods are used for inspection. Ultrasonic testing technique is used for inspection of volume, eddy current technique, for copper components only, and visual testing technique are used for inspection of the surface and near surface area

  20. Dinuclear bis-beta-diketonato ligand derivatives of iron(III) and copper(II) and use of the latter as components for the assembly of extended metallo-supramolecular structures.

    Science.gov (United States)

    Clegg, Jack K; Lindoy, Leonard F; McMurtrie, John C; Schilter, David

    2005-03-07

    A range of 1,3-aryl linked, bis-beta-diketone derivatives (LH2) has been employed to synthesise neutral bis(ligand), dinuclear complexes incorporating square-planar copper(II) and tris(ligand) dinuclear helical derivatives containing octahedral iron(III). The 1H NMR spectra of the free ligands contain singlet peaks at ca. 16.2 ppm, indicative of enolic protons, confirming that the (bis) enol tautomer is present in solution. An X-ray structure of a ligand from the series incorporating tert-butyl terminal substituents confirms that the same tautomer persists in the solid and that the relative orientation of the bis-beta-diketone fragments is such that the coordination vectors lie at approximately 120 degrees to each other. The planar, dinuclear copper complexes form 1 : 2 adducts with pyridine and 4-(dimethylamino)pyridine, confirmed by X-ray structures, that incorporate five-coordinate metal centres. Based on this behaviour, the prospect of linking copper centres in the dinuclear complexes using the difunctional heterocyclic bases, 4,4'-bipyridine, 4,4'-trans-azopyridine and pyrazine as co-ligands has been probed. However, 4,4'-bipyridine was observed to coordinate through only one of its heterocyclic nitrogen atoms in the solid state to form a 1 : 2 ([Cu2(L)2]: 4,4'-bipyridine) adduct, analogous to the structures obtained with the above mono-functional nitrogen bases. Nevertheless, an X-ray structure determination shows that the related difunctional base, 4,4'-trans-azopyridine, coordinates in a bridging fashion via both its heterocyclic nitrogen atoms on alternate sides of each planar [Cu2(L)2] unit to produce an infinite one dimensional metallo chain. In contrast, with pyrazine, a new neutral, discrete assembly of type [Cu4(L)4(pyrazine)2] is formed. The X-ray structure shows that two planar dinuclear complexes are linked by two pyrazine molecules in a sandwich arrangement such that the coordination environment of each copper ion is approximately square pyramidal

  1. Bioaccumulation of copper ions by Escherichia coli expressing vanabin genes from the vanadium-rich ascidian Ascidia sydneiensis samea.

    Science.gov (United States)

    Ueki, Tatsuya; Sakamoto, Yasuhisa; Yamaguchi, Nobuo; Michibata, Hitoshi

    2003-11-01

    The genes encoding two vanadium-binding proteins, vanabin1 and vanabin2, from a vanadium-rich ascidian, Ascidia sydneiensis samea, were recently identified and cloned (T. Ueki, T. Adachi, S. Kawano, M. Aoshima, N. Yamaguchi, K. Kanamori, and H. Michibata, Biochim. Biophys. Acta 1626:43-50, 2003). The vanabins were found to bind vanadium(IV), and an excess of copper(II) ions inhibited the binding of vanadium(IV) to the vanabins in vitro. In this study, we constructed Escherichia coli strains that expressed vanabin1 or vanabin2 fused to maltose-binding protein (MBP) in the periplasmic space. We found that both strains accumulated about twenty times more copper(II) ions than the control BL21 strain, while no significant accumulation of vanadium was observed. The strains expressing either MBP-vanabin1 or MBP-vanabin2 absorbed approximately 70% of the copper ions in the medium to which 10 micro M copper (II) ions were initially added. The MBP-vanabin1 and MBP-vanabin2 protein expressed in the periplasm bound to copper ions at a copper:protein molar ratio of 8:1 and 5:1, respectively, but MBP did not bind to copper ions. These data showed that the metal-binding proteins vanabin1 and vanabin2 bound copper ions directly and enhanced the bioaccumulation of copper ions by E. coli.

  2. Estimation of the binding modes with important human cytochrome P450 enzymes, drug interaction potential, pharmacokinetics, and hepatotoxicity of ginger components using molecular docking, computational, and pharmacokinetic modeling studies.

    Science.gov (United States)

    Qiu, Jia-Xuan; Zhou, Zhi-Wei; He, Zhi-Xu; Zhang, Xueji; Zhou, Shu-Feng; Zhu, Shengrong

    2015-01-01

    Ginger is one of the most commonly used herbal medicines for the treatment of numerous ailments and improvement of body functions. It may be used in combination with prescribed drugs. The coadministration of ginger with therapeutic drugs raises a concern of potential deleterious drug interactions via the modulation of the expression and/or activity of drug-metabolizing enzymes and drug transporters, resulting in unfavorable therapeutic outcomes. This study aimed to determine the molecular interactions between 12 main active ginger components (6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 8-shogaol, 10-shogaol, ar-curcumene, β-bisabolene, β-sesquiphelandrene, 6-gingerdione, (-)-zingiberene, and methyl-6-isogingerol) and human cytochrome P450 (CYP) 1A2, 2C9, 2C19, 2D6, and 3A4 and to predict the absorption, distribution, metabolism, excretion, and toxicity (ADMET) of the 12 ginger components using computational approaches and comprehensive literature search. Docking studies showed that ginger components interacted with a panel of amino acids in the active sites of CYP1A2, 2C9, 2C19, 2D6, and 3A4 mainly through hydrogen bond formation, to a lesser extent, via π-π stacking. The pharmacokinetic simulation studies showed that the [I]/[Ki ] value for CYP2C9, 2C19, and 3A4 ranged from 0.0002 to 19.6 and the R value ranged from 1.0002 to 20.6 and that ginger might exhibit a high risk of drug interaction via inhibition of the activity of human CYP2C9 and CYP3A4, but a low risk of drug interaction toward CYP2C19-mediated drug metabolism. Furthermore, it has been evaluated that the 12 ginger components possessed a favorable ADMET profiles with regard to the solubility, absorption, permeability across the blood-brain barrier, interactions with CYP2D6, hepatotoxicity, and plasma protein binding. The validation results showed that there was no remarkable effect of ginger on the metabolism of warfarin in humans, whereas concurrent use of ginger and nifedipine exhibited a

  3. Copper and silver halates

    CERN Document Server

    Woolley, EM; Salomon, M

    2013-01-01

    Copper and Silver Halates is the third in a series of four volumes on inorganic metal halates. This volume presents critical evaluations and compilations for halate solubilities of the Group II metals. The solubility data included in this volume are those for the five compounds, copper chlorate and iodate, and silver chlorate, bromate and iodate.

  4. Enrichment of copper and recycling of cyanide from copper-cyanide waste by solvent extraction

    Science.gov (United States)

    Gao, Teng-yue; Liu, Kui-ren; Han, Qing; Xu, Bin-shi

    2016-11-01

    The enrichment of copper from copper-cyanide wastewater by solvent extraction was investigated using a quaternary ammonium salt as an extractant. The influences of important parameters, e.g., organic-phase components, aqueous pH values, temperature, inorganic anion impurities, CN/Cu molar ratio, and stripping reagents, were examined systematically, and the optimal conditions were determined. The results indicated that copper was effectively concentrated from low-concentration solutions using Aliquat 336 and that the extraction efficiency increased linearly with increasing temperature. The aqueous pH value and concentrations of inorganic anion impurities only weakly affected the extraction process when varied in appropriate ranges. The CN/Cu molar ratio affected the extraction efficiency by changing the distribution of copper-cyanide complexes. The difference in gold leaching efficiency between using raffinate and fresh water was negligible.

  5. Synthesis and crystal structure determination of copper(II)-complex: In vitro DNA and HSA binding, pBR322 plasmid cleavage, cell imaging and cytotoxic studies.

    Science.gov (United States)

    Tabassum, Sartaj; Zaki, Mehvash; Ahmad, Musheer; Afzal, Mohd; Srivastav, Saurabh; Srikrishna, Saripella; Arjmand, Farukh

    2014-08-18

    New Cu(II) complex 1 of indole-3-propionic acid and 1,10-phenanthroline was synthesized and characterized by analytical, spectroscopic and single crystal X-ray diffraction. In vitro DNA binding studies of 1 was performed by employing UV-vis and fluorescence spectroscopic techniques. The binding affinity towards human serum albumin (HSA) was also investigated to understand the carrier role in body system, as the time dependent HPLC experiment of 1 revealed that bonded drug with protein releases slowly in presence of DNA. Complex 1 exhibited good anti-tumor activity (GI50 values <10 μg/ml), and to elucidate the mechanism of tumor inhibition, topoisomerase I enzymatic activity was carried out and further validated by cell imaging studies which clearly showed its nuclear localization. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  6. Thermodynamic data for copper. Implications for the corrosion of copper under repository conditions

    International Nuclear Information System (INIS)

    Puigdomenech, I.; Taxen, C.

    2000-08-01

    The stability of copper canisters has a central role in the safety concept for the planned nuclear spent fuel repository in Sweden. The corrosion of copper canisters will be influenced by the chemical and physical environment in the near-field of the repository, and thermodynamic equilibrium calculations provide the basis for understanding this system. Thermodynamic data have been selected in this work for solids and aqueous species in the system: Cu - H 2 O - H + - H 2 - F - - Cl - - S 2- - SO 4 2- - NO 3 - - NO 2 - - NH 4 + PO 4 3- - CO 3 2+ . For some reactions and compounds, for which no experimental information on temperature effects was available, entropy and heat capacity values have been estimated. The compiled data were used to calculate thermodynamic equilibria for copper systems up to 100 deg C. The stability of copper in contact with granitic groundwaters has been illustrated using chemical equilibrium diagrams, with he following main conclusions: Dissolved sulphide and O 2 in groundwater are the most damaging components for copper corrosion. If available, HS - will react quantitatively with copper to form a variety of sulphides. However, sulphide concentrations in natural waters are usually low, because it forms sparingly soluble solids with transition metals, including Fe(II), which is wide-spread in reducing environments. Chloride can affect negatively copper corrosion. High concentrations (e.g., [Cl - ]TOT > 60 g/l) may be unfavourable for the general corrosion of copper in combination with in the following circumstances: Low pH ( + . The negative effects of Cl - are emphasised at higher temperatures. The chloride-enhancement of general corrosion may be beneficial for localised corrosion: pitting and stress corrosion cracking. The concept of redox potential, E H , has been found to be inadequate to describe copper corrosion in a nuclear repository. The available amounts of oxidants/reductants, and the stoichiometry of the corrosion reactions are

  7. Enhancement of pigment concentrations in Dunaliella tertiolecta as a result of copper toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Lustigman, B.K.

    1986-11-01

    The addition of copper to coastal waters through the disposal of complex effluents has been increasing. Copper is a well known algicide. It binds to the cell membrane, effects permeability mechanisms and attaches to SH groups on vital enzymes. The ability of algae to withstand copper toxicity varies greatly. The green flagellate, Dunaliella tertiolecta has previously been shown to be highly resistant to copper. Its ability to withstand high concentrations of copper promotes growth of Dunaliella in coastal waters contaminated with increased copper concentrations. Dunaliella tertiolecta possesses chlorophylls a and b, small amounts of alpha- and greater amounts of beta-carotene as well as neoxanthin, zeaxanthin and lutein. This study was undertaken to determine the effect of lethal and sublethal concentrations of copper on the growth and production of chlorophyll and carotenoids in Dunaliella tertiolecta.

  8. Bioaccessibility and Solubility of Copper in Copper-Treated Lumber

    Science.gov (United States)

    Micronized copper (MC)-treated lumber is a recent replacement for Chromated Copper Arsenate (CCA) and Ammonium Copper (AC)-treated lumbers; though little is known about the potential risk of copper (Cu) exposure from incidental ingestion of MC-treated wood. The bioaccessibility o...

  9. Capacity of waters in the Magela Creek system, Northern Territory, to complex copper and cadmium

    International Nuclear Information System (INIS)

    Hart, B.T.; Davies, S.H.R.

    1984-08-01

    Two methods were used to determine the concentrations of copper-binding ligand (complexing capacity) and conditional formation constants for waters collected from the Magela Creek system, Northern Territory. These data are particularly important in estimating the concentrations of toxic forms of copper that may result from particular effluent discharge strategies from the Ranger uranium operation

  10. In vitro thermodynamic dissection of human copper transfer from chaperone to target protein.

    Science.gov (United States)

    Niemiec, Moritz S; Weise, Christoph F; Wittung-Stafshede, Pernilla

    2012-01-01

    Transient protein-protein and protein-ligand interactions are fundamental components of biological activity. To understand biological activity, not only the structures of the involved proteins are important but also the energetics of the individual steps of a reaction. Here we use in vitro biophysical methods to deduce thermodynamic parameters of copper (Cu) transfer from the human copper chaperone Atox1 to the fourth metal-binding domain of the Wilson disease protein (WD4). Atox1 and WD4 have the same fold (ferredoxin-like fold) and Cu-binding site (two surface exposed cysteine residues) and thus it is not clear what drives metal transfer from one protein to the other. Cu transfer is a two-step reaction involving a metal-dependent ternary complex in which the metal is coordinated by cysteines from both proteins (i.e., Atox1-Cu-WD4). We employ size exclusion chromatography to estimate individual equilibrium constants for the two steps. This information together with calorimetric titration data are used to reveal enthalpic and entropic contributions of each step in the transfer process. Upon combining the equilibrium constants for both steps, a metal exchange factor (from Atox1 to WD4) of 10 is calculated, governed by a negative net enthalpy change of ∼10 kJ/mol. Thus, small variations in interaction energies, not always obvious upon comparing protein structures alone, may fuel vectorial metal transfer.

  11. Contribution of natural organic matter to copper leaching from municipal solid waste incinerator bottom ash.

    Science.gov (United States)

    Van Zomeren, André; Comans, Rob N J

    2004-07-15

    The leaching of heavy metals, such as copper, from municipal solid waste incinerator (MSWI) bottom ash is a concern in many countries and may inhibit the beneficial reuse of this secondary material. The enhanced leaching of copper from three MSWI bottom ash samples by dissolved organic carbon (DOC) was investigated with specific attention for the nature of the organic ligands. A competitive ligand exchange-solvent extraction (CLE-SE) method was used to measure Cu binding to DOC. Two types of binding sites for Cu were identified and geochemical modeling showed that the organically bound fraction varied from 82% to 100% between pH 6.6 and 10.6. Model calculations showed that complexation by previously identified aliphatic and aromatic acids was unable to explain the enhanced Cu leaching from the MSWI residues. High-performance size-exclusion chromatography (HPSEC) and the standard extraction procedure to isolate and purify natural organic matter revealed that about 0.5% of DOC consists of humic acids and 14.3-25.6% consists of fulvic acids. Calculated Cu binding isotherms based on these natural organic compounds, and the nonideal competitive adsorption-Donnan (NICA-Donnan) model, provide an adequate description of the organic Cu complexation in the bottom ash leachates. The results show that fulvic acid-type components exist in MSWI bottom ash leachates and are likely responsible for the generally observed enhanced Cu leaching from these residues. These findings enable the use of geochemical speciation programs, which include models and intrinsic parameters for metal binding to natural organic matter, to predict Cu leaching from this widely produced waste material under variable environmental conditions (e.g., pH, ionic strength, and concentrations of competing metals). The identified role of fulvic acids in the leaching of Cu and possibly other heavy metals can also be used in the development of techniques to improve the environmental quality of MSWI bottom ash.

  12. Posttranslational regulation of copper transporters

    NARCIS (Netherlands)

    van den Berghe, P.V.E.

    2009-01-01

    The transition metal copper is an essential cofactor for many redox-active enzymes, but excessive copper can generate toxic reactive oxygen species. Copper homeostasis is maintained by highly conserved proteins, to balance copper uptake, distribution and export on the systemic and cellular level.

  13. Canine Copper-Associated Hepatitis

    NARCIS (Netherlands)

    Dirksen, Karen|info:eu-repo/dai/nl/412424428; Fieten, Hille|info:eu-repo/dai/nl/314112596

    2017-01-01

    Copper-associated hepatitis is recognized with increasing frequency in dogs. The disease is characterized by centrolobular hepatic copper accumulation, leading to hepatitis and eventually cirrhosis. The only way to establish the diagnosis is by histologic assessment of copper distribution and copper

  14. COPPER CABLE RECYCLING TECHNOLOGY

    International Nuclear Information System (INIS)

    Chelsea Hubbard

    2001-01-01

    The United States Department of Energy (DOE) continually seeks safer and more cost-effective technologies for use in deactivation and decommissioning (D and D) of nuclear facilities. The Deactivation and Decommissioning Focus Area (DDFA) of the DOE's Office of Science and Technology (OST) sponsors large-scale demonstration and deployment projects (LSDDPs). At these LSDDPs, developers and vendors of improved or innovative technologies showcase products that are potentially beneficial to the DOE's projects and to others in the D and D community. Benefits sought include decreased health and safety risks to personnel and the environment, increased productivity, and decreased costs of operation. The Idaho National Engineering and Environmental Laboratory (INEEL) generated a list of statements defining specific needs and problems where improved technology could be incorporated into ongoing D and D tasks. One such need is to reduce the volume of waste copper wire and cable generated by D and D. Deactivation and decommissioning activities of nuclear facilities generates hundreds of tons of contaminated copper cable, which are sent to radioactive waste disposal sites. The Copper Cable Recycling Technology separates the clean copper from contaminated insulation and dust materials in these cables. The recovered copper can then be reclaimed and, more importantly, landfill disposal volumes can be reduced. The existing baseline technology for disposing radioactively contaminated cables is to package the cables in wooden storage boxes and dispose of the cables in radioactive waste disposal sites. The Copper Cable Recycling Technology is applicable to facility decommissioning projects at many Department of Energy (DOE) nuclear facilities and commercial nuclear power plants undergoing decommissioning activities. The INEEL Copper Cable Recycling Technology Demonstration investigated the effectiveness and efficiency to recycle 13.5 tons of copper cable. To determine the effectiveness

  15. Surface properties of copper based cermet materials

    International Nuclear Information System (INIS)

    Voinea, M.; Vladuta, C.; Bogatu, C.; Duta, A.

    2008-01-01

    The paper presents the characterization of the surface properties of copper based cermets obtained by two different techniques: spray pyrolysis deposition (SPD) and electrodeposition. Copper acetate was used as precursor of Cu/CuO x cermet. The surface morphology was tailored by adding copolymers of maleic anhydride with controlled hydrophobia. The films morphology of Cu/CuO x was assessed using contact angle measurements and AFM analysis. The porous structures obtained via SPD lead to higher liquid adsorption rate than the electrodeposited films. A highly polar liquid - water is recommended as testing liquid in contact angle measurements, for estimating the porosity of copper based cermets, while glycerol can be used to distinguish among ionic and metal predominant structures. Thus, contact angle measurements can be used for a primary evaluation of the films morphology and, on the other hand, of the ratio between the cermet components

  16. Surface properties of copper based cermet materials

    Energy Technology Data Exchange (ETDEWEB)

    Voinea, M. [The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 (Romania)], E-mail: m.voinea@unitbv.ro; Vladuta, C.; Bogatu, C.; Duta, A. [The Centre: Product Design for Sustainable Development, Transilvania University of Brasov, Eroilor 29, 500036 (Romania)

    2008-08-25

    The paper presents the characterization of the surface properties of copper based cermets obtained by two different techniques: spray pyrolysis deposition (SPD) and electrodeposition. Copper acetate was used as precursor of Cu/CuO{sub x} cermet. The surface morphology was tailored by adding copolymers of maleic anhydride with controlled hydrophobia. The films morphology of Cu/CuO{sub x} was assessed using contact angle measurements and AFM analysis. The porous structures obtained via SPD lead to higher liquid adsorption rate than the electrodeposited films. A highly polar liquid - water is recommended as testing liquid in contact angle measurements, for estimating the porosity of copper based cermets, while glycerol can be used to distinguish among ionic and metal predominant structures. Thus, contact angle measurements can be used for a primary evaluation of the films morphology and, on the other hand, of the ratio between the cermet components.

  17. Regular square planer bis-(4,4,4-trifluoro-1-(thiophen-2-yl)butane-1,3-dione)/copper(II) complex: Trans/cis-DFT isomerization, crystal structure, thermal, solvatochromism, hirshfeld surface and DNA-binding analysis

    Science.gov (United States)

    Hema, M. K.; Karthik, C. S.; Warad, Ismail; Lokanath, N. K.; Zarrouk, Abdelkader; Kumara, Karthik; Pampa, K. J.; Mallu, P.

    2018-04-01

    Trans-[Cu(O∩O)2] complex, O∩O = 4,4,4-trifluoro-1-(thiophen-2-yl)butane-1,3-dione was reported with high potential toward CT-DNA binder. The solved XRD-structure of complex indicated a perfect regular square-planer geometry around the Cu(II) center. The trans/cis-DFT-isomerization calculation supported the XRD seen in reflecting the trans-isomer as the kinetic-favor isomer. The desired complex structure was also characterized by conductivity measurement, CHN-elemental analyses, MS, EDX, SEM, UV-Vis., FT-IR, HAS and TG/DTG. The Solvatochromism behavior of the complex was evaluated using four different polar solvents. MPE and Hirshfeld surface analysis (HSA) come to an agreement that fluoride and thiophene protons atoms are with suitable electro-potential environment to form non-classical H-bonds of type CThsbnd H⋯F. The DNA-binding properties were investigated by viscosity tests and spectrometric titrations, the results revealed the complex as strong calf-thymus DNA binder. High intrinsic-binding constants value ∼1.8 × 105 was collected.

  18. Copper in the sea: a bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, R.L.

    1977-04-01

    Life in the sea is vulnerable to the influx of trace metals resulting from man's activities. Although many pollutants introduced to the sea eventually degrade to less harmful forms, trace metals accumulate in sediments and have a continued potential for effect on biota. Copper has a toxic potential exceeding all other metals due to the quantity discharged and its toxicological effect. Fortunately, copper in the oceans is rendered less bioavailable or less toxic by its ready interaction with the complex chemical components of seawater. This bibliography was prepared to illustrate the status of current knowledge of the biogeochemistry of copper and to aid the development of research programs to define the effects of copper discharged to the marine environment. The references are categorized to aid the reader to locate literature concerning specific aspects of the biogeochemistry of copper. A brief comment describing the important findings in each category is given. Although this bibliography is not exhaustive, the listed references are likely representative of current knowledge.

  19. Copper resistance determinants in bacteria.

    Science.gov (United States)

    Brown, N L; Rouch, D A; Lee, B T

    1992-01-01

    Copper is an essential trace element that is utilized in a number of oxygenases and electron transport proteins, but it is also a highly toxic heavy metal, against which all organisms must protect themselves. Known bacterial determinants of copper resistance are plasmid-encoded. The mechanisms which confer resistance must be integrated with the normal metabolism of copper. Different bacteria have adopted diverse strategies for copper resistance, and this review outlines what is known about bacterial copper resistance mechanisms and their genetic regulation.

  20. The PorX Response Regulator of the Porphyromonas gingivalis PorXY Two-Component System Does Not Directly Regulate the Type IX Secretion Genes but Binds the PorL Subunit

    Science.gov (United States)

    Vincent, Maxence S.; Durand, Eric; Cascales, Eric

    2016-01-01

    The Type IX secretion system (T9SS) is a versatile multi-protein complex restricted to bacteria of the Bacteriodetes phylum and responsible for the secretion or cell surface exposition of diverse proteins that participate to S-layer formation, gliding motility or pathogenesis. The T9SS is poorly characterized but a number of proteins involved in the assembly of the secretion apparatus in the oral pathogen Porphyromonas gingivalis have been identified based on genome substractive analyses. Among these proteins, PorY, and PorX encode typical two-component system (TCS) sensor and CheY-like response regulator respectively. Although the porX and porY genes do not localize at the same genetic locus, it has been proposed that PorXY form a bona fide TCS. Deletion of porX in P. gingivalis causes a slight decrease of the expression of a number of other T9SS genes, including sov, porT, porP, porK, porL, porM, porN, and porY. Here, we show that PorX and the soluble cytoplasmic domain of PorY interact. Using electrophoretic mobility shift, DNA-protein co-purification and heterologous host expression assays, we demonstrate that PorX does not bind T9SS gene promoters and does not directly regulate expression of the T9SS genes. Finally, we show that PorX interacts with the cytoplasmic domain of PorL, a component of the T9SS membrane core complex and propose that the CheY-like PorX protein might be involved in the dynamics of the T9SS. PMID:27630829

  1. The PorX response regulator of the Porphyromonas gingivalis PorXY two-component system does not directly regulate the Type IX secretion genes but binds the PorL subunit.

    Directory of Open Access Journals (Sweden)

    Maxence S Vincent

    2016-08-01

    Full Text Available The Type IX secretion system (T9SS is a versatile multi-protein complex restricted to bacteria of the Bacteriodetes phylum and responsible for the secretion of surface attachment of diverse proteins that participate to S-layer formation, gliding motility or pathogenesis. The T9SS is poorly characterized but a number of proteins involved in the assembly of the secretion apparatus in the oral pathogen Porphyromonas gingivalis have been identified based on genome substractive analyses. Among these proteins, PorY and PorX encode typical two-component system (TCS sensor and CheY-like response regulator respectively. Although the porX and porY genes do not localize at the same genetic locus, it has been proposed that PorXY form a bona fide TCS. Deletion of the porX in P. gingivalis causes a slight decrease of the expression of a number of other T9SS genes, including sov, porT, porP, porK, porL, porM, porN and porY. Here, we show that PorX and the soluble cytoplasmic domain of PorY interact. Using electrophoretic mobility shift, DNA-protein co-purification and heterologous host expression assays, we showed that PorX does not bind and does not directly regulate expression of the T9SS genes. Finally, we show that PorX interacts with the cytoplasmic domain of PorL, a component of the T9SS membrane core complex and propose that the CheY-like PorX protein might be involved in the dynamics of the T9SS.

  2. Expression and localization of progesterone receptor membrane component 1 and 2 and serpine mRNA binding protein 1 in the bovine corpus luteum during the estrous cycle and the first trimester of pregnancy.

    Science.gov (United States)

    Kowalik, Magdalena K; Rekawiecki, Robert; Kotwica, Jan

    2014-11-01

    The aim of this study was to evaluate the mRNA and protein expression and the localization of progesterone receptor membrane component 1 (PGRMC1), PGRMC2, and the PGRMC1 partner serpine mRNA binding protein 1 (SERBP1) in the bovine CL on Days 2 to 5, 6 to 10, 11 to 16, and 17 to 20 of the estrous cycle as well as during Weeks 3 to 5, 6 to 8, and 9 to 12 of pregnancy (n = 5-6 per each period). The highest levels of PGRMC1 and PGRMC2 mRNA expression were found on Days 6 to 16 (P cycle and during pregnancy (P cycle compared with the other stages of the estrous cycle and pregnancy, whereas PGRMC2 protein expression (P cycle and was at its lowest (P cows, the patterns of SERBP1 mRNA and protein expression remained constant and were comparable with those observed during the estrous cycle. Progesterone receptor membrane component 1 and PGRMC2 localized to both large and small luteal cells, whereas SERBP1 was observed mainly in small luteal cells and much less frequently in large luteal cells. All proteins were also localized in the endothelial cells of blood vessels. The data obtained indicate the variable expression of PGRMC1, PGRMC2, and SERBP1 mRNA and protein in the bovine CL and suggest that progesterone may regulate CL function via its membrane receptors during both the estrous cycle and pregnancy. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Biochar and compost as amendments in copper-enriched vineyard soils - stabilization or mobilization of copper?

    Science.gov (United States)

    Soja, Gerhard; Fristak, Vladimir; Wimmer, Bernhard; Bell, Stephen; Chamier Glisczinski, Julia; Pardeller, Georg; Dersch, Georg; Rosner, Franz; Wenzel, Walter; Zehetner, Franz

    2016-04-01

    Copper is an important ingredient for several fungicides that have been used in agriculture. For organic viticulture, several diseases as e.g. downy mildew (Plasmopara viticola) can only be antagonized with Cu-containing fungicides. This long-lasting dependence on Cu-fungicides has led to a gradual Cu enrichment of vineyard soils in traditional wine-growing areas, occasionally exceeding 300 mg/kg. Although these concentrations do not affect the vines or wine quality, they may impair soil microbiological functions in the top soil layer or the root growth of green cover plants. Therefore measures are demanded that reduce the bioavailability of copper, thereby reducing the ecotoxicological effects. The use of biochar and compost as soil amendment has been suggested as a strategy to immobilize Cu and reduce the exchangeable fractions. This study consisted of lab and greenhouse experiments that were designed to test the sorption and desorption behavior of copper in vineyard soils with or without biochar and/or compost as soil amendment. Slightly acidic soils (pHeffects were more evident for a reduction of the ionic form Cu2+ than for total soluble copper, even in alkaline soils. Biochar modified with citric or tartaric acid did not significantly decrease the solubility of copper based on total dissolved concentrations although CEC was higher than in unmodified biochar. Treatments consisting of compost only or that had an equal amount of compost and biochar rather had a mobilizing effect on biochar. Sorption experiments with different DOC concentrations and biochar, however, showed a positive effect on copper sorption. Apparently in vineyard soils the predisposition to form organic-Cu-complexes may outbalance the binding possibilities of these complexes to biochar, occasionally resulting in enhanced mobilization. Presumably immobilization of copper with biochar would work best in acidic soils low in organic carbon and with low or no compost addition although this might

  4. Micromachining with copper lasers

    Science.gov (United States)

    Knowles, Martyn R. H.; Bell, Andy; Foster-Turner, Gideon; Rutterford, Graham; Chudzicki, J.; Kearsley, Andrew J.

    1997-04-01

    In recent years the copper laser has undergone extensive development and has emerged as a leading and unique laser for micromachining. The copper laser is a high average power (10 - 250 W), high pulse repetition rate (2 - 32 kHz), visible laser (511 nm and 578 nm) that produces high peak power (typically 200 kW), short pulses (30 ns) and very good beam quality (diffraction limited). This unique set of laser parameters results in exceptional micro-machining in a wide variety of materials. Typical examples of the capabilities of the copper laser include the drilling of small holes (10 - 200 micrometer diameter) in materials as diverse as steel, ceramic, diamond and polyimide with micron precision and low taper (less than 1 degree) cutting and profiling of diamond. Application of the copper laser covers the electronic, aerospace, automotive, nuclear, medical and precision engineering industries.

  5. Sliding Friction of Copper

    National Research Council Canada - National Science Library

    Liu, Tung

    1963-01-01

    .... With less clean surfaces, the coefficient of friction obtained was about 0.4. Since the degree of cleanliness cannot be controlled quantitatively, the friction - load curve of sliding copper pairs in air exhibits a bifurcation characteristic...

  6. Bioorganic compounds as copper corrosion inhibitors in hydrocarbon media

    International Nuclear Information System (INIS)

    Levin, Martina; Wiklund, Per; Leygraf, Christofer

    2012-01-01

    Highlights: ► The corrosion protection of Cu in oil by four bioorganic compounds was examined. ► Utilising the techniques of ellipsometry, AAS and a standard IEC corrosion test. ► It was concluded that adenine and purine exhibited a surface passivating effect. ► Cysteine and histidine did not exhibit a surface passivating effect. - Abstract: The corrosion protection of copper by four bioorganic compounds; adenine, purine, cysteine and histidine, in hydrocarbon media has been examined by in situ ellipsometry, atom absorption spectroscopy and a standard corrosion test. Adenine and purine were found to irreversibly bind to the copper surface. The amount of dissolved copper was severely lowered and the copper surface appeared unaffected. It was concluded that adenine and purine exhibited a surface passivating effect, whereas the effect of cysteine and histidine was significantly lower. The influence on oxidation stability of the medium by addition of the compounds was examined and found to be minor.

  7. LEP copper accelerating cavities

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    These copper cavities were used to generate the radio frequency electric field that was used to accelerate electrons and positrons around the 27-km Large Electron-Positron (LEP) collider at CERN, which ran from 1989 to 2000. The copper cavities were gradually replaced from 1996 with new superconducting cavities allowing the collision energy to rise from 90 GeV to 200 GeV by mid-1999.

  8. Copper and the Prion Protein: Methods, Structures, Function, and Disease

    Science.gov (United States)

    Millhauser, Glenn L.

    2007-05-01

    The transmissible spongiform encephalopathies (TSEs) arise from conversion of the membrane-bound prion protein from PrPC to PrPSc. Examples of the TSEs include mad cow disease, chronic wasting disease in deer and elk, scrapie in goats and sheep, and kuru and Creutzfeldt-Jakob disease in humans. Although the precise function of PrPC in healthy tissues is not known, recent research demonstrates that it binds Cu(II) in an unusual and highly conserved region of the protein termed the octarepeat domain. This review describes recent connections between copper and PrPC, with an emphasis on the electron paramagnetic resonance elucidation of the specific copper-binding sites, insights into PrPC function, and emerging connections between copper and prion disease.

  9. Behaviors and mechanisms of copper adsorption on hydrolyzed polyacrylonitrile fibers.

    Science.gov (United States)

    Deng, Shubo; Bai, Renbi; Chen, J P

    2003-04-15

    Polyacrylonitrile fiber (PANF) was hydrolyzed in a solution of sodium hydroxide and the hydrolyzed polyacrylonitrile fiber (HPANF) was used as an adsorbent to remove copper ions from aqueous solution. Scanning electron microscopy (SEM) showed that the hydrolysis process made the surface of HPANF rougher than that of PANF. Fourier transform infrared (FTIR) spectroscopy revealed that the HPANF contained conjugated imine (-Cz=Nz-) sequences. Batch adsorption results indicated that the HPANF was very effective in adsorbing copper, and the adsorption equilibrium could be reached within 10-20 min. Atomic force microscopy (AFM) showed that some aggregates formed on the surface of the HPANF after copper ion adsorption and the average surface roughness (R(a)) value of the HPANF changed from 0.363 to 3.763 nm due to copper adsorption. FTIR analysis indicated that copper adsorption caused a decrease of the light adsorption intensity of the imine (-Cz=Nz-) groups at 1573 and 1406 cm(-1) wavenumbers, and X-ray photoelectron spectroscopy (XPS) showed that the binding energy (BE) of some of the nitrogen atoms in the HPANF increased to a greater value due to copper adsorption. The FTIR and XPS results suggest that the adsorption of copper ions to the HPANF is attributed to the imine groups on the surface of the HPANF.

  10. A tri-copper(II) complex displaying DNA-cleaving properties and antiproliferative activity against cancer cells.

    Science.gov (United States)

    Suntharalingam, Kogularamanan; Hunt, Douglas J; Duarte, Alexandra A; White, Andrew J P; Mann, David J; Vilar, Ramon

    2012-11-19

    A new disubstituted terpyridine ligand and the corresponding tri-copper(II) complex have been prepared and characterised. The binding affinity and binding mode of this tri-copper complex (as well as the previously reported mono- and di-copper analogues) towards duplex DNA were determined by using UV/Vis spectroscopic titrations and fluorescent indicator displacement (FID) assays. These studies showed the three complexes to bind moderately (in the order of 10(4)  M(-1)) to duplex DNA (ct-DNA and a 26-mer sequence). Furthermore, the number of copper centres and the nature of the substituents were found to play a significant role in defining the binding mode (intercalative or groove binding). The nuclease potential of the three complexes was investigated by using circular plasmid DNA as a substrate and analysing the products by agarose-gel electrophoresis. The cleaving activity was found to be dependent on the number of copper centres present (cleaving potency was in the order: tri-copper>di-copper>mono-copper). Interestingly, the tri-copper complex was able to cleave DNA without the need of external co-reductants. As this complex displayed the most promising nuclease properties, cell-based studies were carried out to establish if there was a direct link between DNA cleavage and cellular toxicity. The tri-copper complex displayed high cytotoxicity against four cancer cell lines. Of particular interest was that it displayed high cytotoxicity against the cisplatin-resistant MOLT-4 leukaemia cell line. Cellular uptake studies showed that the tri-copper complex was able to enter the cell and more importantly localise in the nucleus. Immunoblotting analysis (used to monitor changes in protein levels related to the DNA damage response pathway) and DNA-flow cytometric studies suggested that this tri-copper(II) complex is able to induce cellular DNA damage. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Temporal aspects of copper homeostasis and its crosstalk with hormones

    Directory of Open Access Journals (Sweden)

    Lola ePeñarrubia

    2015-04-01

    Full Text Available To cope with the dual nature of copper as being essential and toxic for cells, plants temporarily adapt the expression of copper homeostasis components to assure its delivery to cuproproteins while avoiding the interference of potential oxidative damage derived from both copper uptake and photosynthetic reactions during light hours. The circadian clock participates in the temporal organization of coordination of plant nutrition adapting metabolic responses to the daily oscillations. This timely control improves plant fitness and reproduction and holds biotechnological potential to drive increased crop yields. Hormonal pathways, including those of abscisic acid, gibberellins, ethylene, auxins, and jasmonates are also under direct clock and light control, both in mono and dicotyledons. In this review, we focus on copper transport in Arabidopsis thaliana and Oryza sativa and the presumable role of hormones in metal homeostasis matching nutrient availability to growth requirements and preventing metal toxicity. The presence of putative hormone-dependent regulatory elements in the promoters of copper transporters genes suggests hormonal regulation to match special copper requirements during plant development. Spatial and temporal processes that can be affected by hormones include the regulation of copper uptake into roots, intracellular trafficking and compartmentalisation, and long-distance transport to developing vegetative and reproductive tissues. In turn, hormone biosynthesis and signalling are also influenced by copper availability, which suggests reciprocal regulation subjected to temporal control by the central oscillator of the circadian clock. This transcriptional regulatory network, coordinates environmental and hormonal signalling with developmental pathways to allow enhanced micronutrient acquisition efficiency.

  12. Biochemical characterization of the human copper transporter Ctr1.

    Science.gov (United States)

    Lee, Jaekwon; Peña, Maria Marjorette O; Nose, Yasuhiro; Thiele, Dennis J

    2002-02-08

    The trace metal copper is an essential cofactor for a number of biological processes including mitochondrial oxidative phosphorylation, free radical detoxification, neurotransmitter synthesis and maturation, and iron metabolism. Consequently, copper transport at the cell surface and the delivery of copper to intracellular proteins are critical events in normal physiology. Little is known about the molecules and biochemical mechanisms responsible for copper uptake at the plasma membrane in mammals. Here, we demonstrate that human Ctr1 (hCtr1) is a component of the copper transport machinery at the plasma membrane. hCtr1 transports copper with high affinity in a time-dependent and saturable manner and is metal-specific. hCtr1-mediated (64)Cu transport is an energy-independent process and is stimulated by extracellular acidic pH and high K(+) concentrations. hCtr1 exists as a homomultimer at the plasma membrane in mammalian cells. This is the first report on the biochemical characterization of the human copper transporter hCtr1, which is important for understanding mechanisms for mammalian copper transport at the plasma membrane.

  13. Thermal Conductivity And Expansion Of Graphite/Copper

    Science.gov (United States)

    Mcdanels, David L.; Ellis, David L.

    1993-01-01

    Report describes fabrication of graphite-fiber/copper-matrix composite plates, measurements of thermal conductivities of plates at temperatures from ambient to 1,073 K, and measurements of thermal expansions of plates from ambient temperature to 1,050 K. Composites promising lightweight, high-thermal-conductivity materials proposed for use in heat exchangers and other heat-transfer components of power systems in spacecraft and hypersonic aircraft. Graphite/copper also of interest as model composite material.

  14. Copper and copper-nickel alloys as zebra mussel antifoulants

    Energy Technology Data Exchange (ETDEWEB)

    Dormon, J.M.; Cottrell, C.M.; Allen, D.G.; Ackerman, J.D.; Spelt, J.K. [Univ. of Toronto, Ontario (Canada)

    1996-04-01

    Copper has been used in the marine environment for decades as cladding on ships and pipes to prevent biofouling by marine mussels (Mytilus edulis L.). This motivated the present investigation into the possibility of using copper to prevent biofouling in freshwater by both zebra mussels and quagga mussels (Dreissena polymorpha and D. bugensis collectively referred to as zebra mussels). Copper and copper alloy sheet proved to be highly effective in preventing biofouling by zebra mussels over a three-year period. Further studies were conducted with copper and copper-nickel mesh (lattice of expanded metal) and screen (woven wire with a smaller hole size), which reduced the amount of copper used. Copper screen was also found to be strongly biofouling-resistant with respect to zebra mussels, while copper mesh reduced zebra mussel biofouling in comparison to controls, but did not prevent it entirely. Preliminary investigations into the mechanism of copper antifouling, using galvanic couples, indicated that the release of copper ions from the surface of the exposed metal into the surrounding water is directly or indirectly responsible for the biofouling resistance of copper.

  15. Electrical conduction in composites containing copper core-copper ...

    Indian Academy of Sciences (India)

    Composites of nanometre-sized copper core-copper oxide shell with diameters in the range 6.1 to 7.3 nm dispersed in a silica gel were synthesised by a technique comprising reduction followed by oxidation of a suitably chosen precursor gel. The hot pressed gel powders mixed with nanometre-sized copper particles ...

  16. Influence of valence state of copper ions on structural and spectroscopic properties of multi-component PbO-Al2O3-TeO2-GeO2-SiO2 glass ceramic system- a possible material for memory switching devices

    Science.gov (United States)

    Tirupataiah, Ch.; Narendrudu, T.; Suresh, S.; Srinivasa Rao, P.; Vinaya Teja, P. M.; Sambasiva Rao, M. V.; Chinna Ram, G.; Krishna Rao, D.

    2017-11-01

    Multi-component glass ceramics with composition 29PbO-5Al2O3-1TeO2 -10GeO2- (55-x) SiO2 doped with different concentrations of CuO (0 ≤ x ≤ 1.0 mol %) were synthesized by melt quenching technique and subsequent heat treatment. These glass ceramics were characterized by X-ray diffraction, scanning electron microscope, differential thermal analysis, optical absorption, electron paramagnetic resonance, Fourier transform infrared and Raman studies. The absorption spectra of these glass ceramics exhibited a broad absorption band in the range 650-950 nm which is ascribed to 2B1g → 2B2g octahedral transition of Cu2+ ions. A feeble band around 364 nm is also identified in the samples doped with CuO up to 0.6 mol% as being due to charge transfer between the two oxidation states Cu2+ and Cu+ of copper ions. The EPR spectrum recorded at room temperature exhibited a strong resonance signal at g⊥ = 2.072 and a shallow quadruplet at about gǁ = 2.401. FTIR and Raman spectra of the titled samples provide significant information about various structural units viz., silicate, germanate, PbO4, PbO6, AlO6, TeO4 and TeO3 that are present in these ceramic matrix. Analysis of the spectroscopic investigations reveals that with an increase in the concentration of CuO up to 0.6 mol% copper ions do exist in Cu2+ and Cu+ states and they act as modifiers and net work formers respectively. Therefore, glass ceramic sample contains 0.6 mol% of CuO is favorable for memory switching action.

  17. Streptococcus mutans copper chaperone, CopZ, is critical for biofilm formation and competitiveness.

    Science.gov (United States)

    Garcia, S S; Du, Q; Wu, H

    2016-12-01

    The oral cavity is a dynamic environment characterized by hundreds of bacterial species, saliva, and an influx of nutrients and metal ions such as copper. Although there is a physiologic level of copper in the saliva, the oral cavity is often challenged with an influx of copper ions. At high concentrations copper is toxic and must therefore be strictly regulated by pathogens for them to persist and cause disease. The cariogenic pathogen Streptococcus mutans manages excess copper using the copYAZ operon that encodes a negative DNA-binding repressor (CopY), the P1-ATPase copper exporter (CopA), and the copper chaperone (CopZ). These hypothetical roles of the copYAZ operon in regulation and copper transport to receptors led us to investigate their contribution to S. mutans virulence. Mutants defective in the copper chaperone CopZ, but not CopY or CopA, were impaired in biofilm formation and competitiveness against commensal streptococci. Characterization of the CopZ mutant biofilm revealed a decreased secretion of glucosyltransferases and reduced expression of mutacin genes. These data suggest that the function of copZ on biofilm and competitiveness is independent of copper resistance and CopZ is a global regulator for biofilm and other virulence factors. Further characterization of CopZ may lead to the identification of new biofilm pathways. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Membrane Anchoring and Ion-Entry Dynamics in P-type ATPase Copper Transport

    DEFF Research Database (Denmark)

    Grønberg, Christina; Sitsel, Oleg; Lindahl, Erik

    2016-01-01

    Cu(+)-specific P-type ATPase membrane protein transporters regulate cellular copper levels. The lack of crystal structures in Cu(+)-binding states has limited our understanding of how ion entry and binding are achieved. Here, we characterize the molecular basis of Cu(+) entry using molecular...... and provide a molecular understanding of ion entry in Cu(+)-transporting P-type ATPases....

  19. Oleuropein shows copper complexing properties and noxious effect on cultured SH-SY5Y neuroblastoma cells depending on cell copper content.

    Science.gov (United States)

    Capo, Concetta R; Pedersen, Jens Z; Falconi, Mattia; Rossi, Luisa

    2017-12-01

    The secoiridoid oleuropein is a non-flavonoid polyphenol, found in the fruit, leaves and food derivatives from Olea europea. Like other polyphenols it shows a very low toxicity towards healthy tissues and a protective action against cancer or neurodegeneration, but its mechanism of action is not yet understood. In the present report we have used optical and ESR spectroscopy as well as molecular modelling to demonstrate that oleuropein forms a complex with the transition metal copper; the dysmetabolism of this metal is suspected to be involved in both cancer and neurodegeneration. Experiments carried out with the aglycon derivative of oleuropein, produced by β-glycosidase treatment of oleuropein glycoside, showed that also the aglycon forms copper-complexes, but with different spectroscopic features than the glycosidic form. Molecular modelling analysis confirmed that two oleuropein molecules (glycosidic or aglycon forms) can easily coordinate one copper ion. The relationship between oleuropein and copper was investigated in SH-SY5Y human neuroblastoma cells. When cells were depleted of copper by treatment with the copper chelator triethylenetetramine (Trien), that binds copper with higher affinity than oleuropein, oleuropein was less toxic than to copper-adequate cells. Conversely, incubation of SH-SY5Y cells with exogenous copper sulphate increased cell susceptibility to oleuropein. Furthermore SH-SY5Y cells differentiated by retinoic acid pre-treatment showed a lower level of copper, and were more resistant to oleuropein treatment. The oleuropein aglycon was not toxic towards SH-SY5Y cells. In conclusion, the copper-oleuropein complex may be involved in the toxicity of oleuropein towards tumour cells, depending on their copper level. Copyright © 2017 Elsevier GmbH. All rights reserved.

  20. The Effect of Orthophosphate as a Copper Corrosion Inhibitor in High Alkalinity Drinking Water Systems

    Science.gov (United States)

    2007-03-01

    in the near future. 7 2.2. Human Health Concerns In the human body, copper is a component of proteins that perform a range of functions...Studies have shown that on average, daily copper intake is 3200 μg. Copper comes from foods such as shellfish, meat, eggs, vegetables , nuts...dehydration synthesis, have a tendency to hydrolyze to orthophosphate in the presence of water, therefore altering their corrosion control mechanism (Cantor

  1. Odontologic use of copper/aluminum alloys: mitochondrial respiration as sensitive parameter of biocompatibility

    OpenAIRE

    Rodrigues,Luiz Erlon A.; Carvalho,Antônio A.V.F.; Azevedo,Antônio L.M.; Cruz,Cecília B.B.V.; Maia,Antônio Wanderley C.

    2003-01-01

    Copper/aluminum alloys are largely utilized in odontological restorations because they are less expensive than gold or platinum. However, tarnishing and important corrosion in intrabuccal prostheses made with copper/aluminum alloys after 28 days of use have been reported. Several kinds of food and beverage may attack and corrode these alloys. Copper is an essential component of several important enzymes directly involved in mitochondrial respiratory metabolism. Aluminum, in contrast, is very ...

  2. Synthesis and enantiopreferential DNA-binding profile of late 3d transition metal R- and S-enantiomeric complexes derived from N,N-bis-(1-benzyl-2-ethoxyethane): Validation of R-enantiomer of copper(II) complex as a human topoisomerase II inhibitor.

    Science.gov (United States)

    Arjmand, Farukh; Sharma, Girish Chandra; Muddassir, Mohd; Tabassum, Sartaj

    2011-08-01

    To evaluate the biological preference of chiral drug candidates for molecular target DNA, new potential metal-based chemotherapeutic agents 1-3 (a and b) of late 3d transition metals Ni(II), Cu(II), and Zn(II), respectively, derived from (R)- and (S)-2-amino-2-phenylethanol with CH(2) CH(2)  linker were synthesized and thoroughly characterized. Interaction studies of 1-3 (a and b) with calf thymus DNA in Tris buffer were studied by electronic absorption titrations, luminescence titrations, cyclic voltammetry, and circular dichroism. The results reveal that the extent of DNA binding of R-enantiomer of copper 1a was highest in comparison to rest of the complexes via electrostatic interaction mode. The nuclease activity of 1(a and b) with supercoiled pBR322 DNA was further examined by gel electrophoresis, which reveals that complex 1a exhibits a remarkable DNA cleavage activity (concentration dependent) with pBR322DNA, and the cleavage activity of both enantiomers of complex 1 was significantly enhanced in the presence of activators. The activating efficiency follows the order Asc > H(2) O(2) > MPA for 1a, and reverse order was observed for 1b, because of the differences in enantioselectivity and conformation. Further, it was observed that cleavage reaction involves singlet oxygen species and superoxide radicals via oxidative cleavage mechanism. In addition, complex 1a exhibits significant inhibitory effects on the topoisomerase II (topo II) activity at a very low concentration ∼24 μM, which suggest that complex 1a is indeed catalytic inhibitor or (poison) of human topo II. Copyright © 2011 Wiley-Liss, Inc.

  3. Coping with copper

    DEFF Research Database (Denmark)

    Nunes, Ines Marques; Jacquiod, Samuel Jehan Auguste; Brejnrod, Asker Daniel

    2016-01-01

    Copper has been intensively used in industry and agriculture since mid-18(th) century and is currently accumulating in soils. We investigated the diversity of potential active bacteria by 16S rRNA gene transcript amplicon sequencing in a temperate grassland soil subjected to century-long exposure...

  4. and copper(II)

    Indian Academy of Sciences (India)

    Unknown

    characterization of several imidazolate-bridged binuclear copper(II) complexes have been reported 1–17. ... of the desired complex formed were collected, washed with ethanol and dried in vacuo at room temperature. .... 16. Sigel H (ed.) 1981 Metal ions in biological system (New York: Marcel Dekker) vol 13, p. 259. 17.

  5. Aspergillus fumigatus Copper Export Machinery and Reactive Oxygen Intermediate Defense Counter Host Copper-Mediated Oxidative Antimicrobial Offense

    Directory of Open Access Journals (Sweden)

    Philipp Wiemann

    2017-05-01

    Full Text Available The Fenton-chemistry-generating properties of copper ions are considered a potent phagolysosome defense against pathogenic microbes, yet our understanding of underlying host/microbe dynamics remains unclear. We address this issue in invasive aspergillosis and demonstrate that host and fungal responses inextricably connect copper and reactive oxygen intermediate (ROI mechanisms. Loss of the copper-binding transcription factor AceA yields an Aspergillus fumigatus strain displaying increased sensitivity to copper and ROI in vitro, increased intracellular copper concentrations, decreased survival in challenge with murine alveolar macrophages (AMΦs, and reduced virulence in a non-neutropenic murine model. ΔaceA survival is remediated by dampening of host ROI (chemically or genetically or enhancement of copper-exporting activity (CrpA in A. fumigatus. Our study exposes a complex host/microbe multifactorial interplay that highlights the importance of host immune status and reveals key targetable A. fumigatus counter-defenses.

  6. A mechanistic study of the uniform corrosion of copper in compacted clay-sand soil

    International Nuclear Information System (INIS)

    Litke, C.D.; Ryan, S.R.; King, F.

    1992-08-01

    The results of a study of the mechanism of uniform corrosion of copper under simulated nuclear fuel waste disposal conditions are presented. Evidence is given that suggests that the rate-controlling process is the transport of copper corrosion products away from the corroding surface. In the experiments described here, the copper diffused through a column of compacted clay-sand buffer. The properties of the buffer material, especially its ability to sorb copper species, are significant in determining the rate of uniform corrosion of copper. The evidence that copper diffusion is rate-controlling stems from the effect of γ-radiation on the tests. In the presence of γ-radiation, copper diffused farther along the column of compacted buffer material than in the unirradiated tests, but the corrosion rate was lower. These two effects can be best explained in terms of a slow copper-diffusion process. Irradiation is thought to reduce the extent of sorption of copper by the clay component of the buffer. This results in a more mobile copper species and a smaller interfacial flux of copper (i.e., a lower corrosion rate)

  7. Detention of copper by sulfur nanoparticles inhibits the proliferation of A375 malignant melanoma and MCF-7 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hao [Department of Chemistry, Jinan University, Guangzhou (China); Zhang, Yikai [Institute of Hematology, Jinan University, Guangzhou (China); Zheng, Shanyuan [School of Life Sciences, The Chinese University of Hong Kong, Hong Kong (China); Weng, Zeping; Ma, Jun [First Affiliated Hospital, Jinan University, Guangzhou (China); Li, Yangqiu [Institute of Hematology, Jinan University, Guangzhou (China); First Affiliated Hospital, Jinan University, Guangzhou (China); Key Laboratory for Regenerative Medicine of Ministry of Education, Jinan University, Guangzhou, 510632 (China); Xie, Xinyuan [Department of Chemistry, Jinan University, Guangzhou (China); Zheng, Wenjie, E-mail: tzhwj@jnu.edu.cn [Department of Chemistry, Jinan University, Guangzhou (China)

    2016-09-02

    Selective induction of cell death or growth inhibition of cancer cells is the future of chemotherapy. Clinical trials have found that cancer tissues are enriched with copper. Based on this finding, many copper-containing compounds and complexes have been designed to “copper” cancer cells using copper as bait. However, recent studies have demonstrated that copper boosts tumor development, and copper deprivation from serum was shown to effectively inhibit the promotion of cancer. Mechanistically, copper is an essential cofactor for mitogen-activated protein kinase (MAPK)/extracellular activating kinase (ERK) kinase (MEK), a central molecule in the BRAF/MEK/ERK pathway. Therefore, depleting copper from cancer cells by directly sequestering copper has a wider field for research and potential for combination therapy. Based on the affinity between sulfur and copper, we therefore designed sulfur nanoparticles (Nano-S) that detain copper, achieving tumor growth restriction. We found that spherical Nano-S could effectively bind copper and form a tighter surficial structure. Moreover, this Nano-S detention of copper effectively inhibited the proliferation of A375 melanoma and MCF-7 breast cancer cells with minimum toxicity to normal cells. Mechanistic studies revealed that Nano-S triggered inactivation of the MEK-ERK pathway followed by inhibition of the proliferation of the A375 and MCF-7 cells. In addition, lower Nano-S concentrations and shorter exposure stimulated the expression of a copper transporter as compensation, which further increased the cellular uptake and anticancer activities of cisplatin. Collectively, our results highlight the potential of Nano-S as an anticancer agent or adjuvant through its detention of copper. - Highlights: • Nano-S selectively inhibited the mitosis of A375 and MCF-7 cells by depleting copper. • Nano-S inactivated MEK/ERK pathway through the detention of copper. • Nano-S improved the cellular uptake and anticancer activities

  8. Detention of copper by sulfur nanoparticles inhibits the proliferation of A375 malignant melanoma and MCF-7 breast cancer cells

    International Nuclear Information System (INIS)

    Liu, Hao; Zhang, Yikai; Zheng, Shanyuan; Weng, Zeping; Ma, Jun; Li, Yangqiu; Xie, Xinyuan; Zheng, Wenjie

    2016-01-01

    Selective induction of cell death or growth inhibition of cancer cells is the future of chemotherapy. Clinical trials have found that cancer tissues are enriched with copper. Based on this finding, many copper-containing compounds and complexes have been designed to “copper” cancer cells using copper as bait. However, recent studies have demonstrated that copper boosts tumor development, and copper deprivation from serum was shown to effectively inhibit the promotion of cancer. Mechanistically, copper is an essential cofactor for mitogen-activated protein kinase (MAPK)/extracellular activating kinase (ERK) kinase (MEK), a central molecule in the BRAF/MEK/ERK pathway. Therefore, depleting copper from cancer cells by directly sequestering copper has a wider field for research and potential for combination therapy. Based on the affinity between sulfur and copper, we therefore designed sulfur nanoparticles (Nano-S) that detain copper, achieving tumor growth restriction. We found that spherical Nano-S could effectively bind copper and form a tighter surficial structure. Moreover, this Nano-S detention of copper effectively inhibited the proliferation of A375 melanoma and MCF-7 breast cancer cells with minimum toxicity to normal cells. Mechanistic studies revealed that Nano-S triggered inactivation of the MEK-ERK pathway followed by inhibition of the proliferation of the A375 and MCF-7 cells. In addition, lower Nano-S concentrations and shorter exposure stimulated the expression of a copper transporter as compensation, which further increased the cellular uptake and anticancer activities of cisplatin. Collectively, our results highlight the potential of Nano-S as an anticancer agent or adjuvant through its detention of copper. - Highlights: • Nano-S selectively inhibited the mitosis of A375 and MCF-7 cells by depleting copper. • Nano-S inactivated MEK/ERK pathway through the detention of copper. • Nano-S improved the cellular uptake and anticancer activities

  9. Presenilin promotes dietary copper uptake.

    Directory of Open Access Journals (Sweden)

    Adam Southon

    Full Text Available Dietary copper is essential for multicellular organisms. Copper is redox active and required as a cofactor for enzymes such as the antioxidant Superoxide Dismutase 1 (SOD1. Copper dyshomeostasis has been implicated in Alzheimer's disease. Mutations in the presenilin genes encoding PS1 and PS2 are major causes of early-onset familial Alzheimer's disease. PS1 and PS2 are required for efficient copper uptake in mammalian systems. Here we demonstrate a conserved role for presenilin in dietary copper uptake in the fly Drosophila melanogaster. Ubiquitous RNA interference-mediated knockdown of the single Drosophila presenilin (PSN gene is lethal. However, PSN knockdown in the midgut produces viable flies. These flies have reduced copper levels and are more tolerant to excess dietary copper. Expression of a copper-responsive EYFP construct was also lower in the midgut of these larvae, indicative of reduced dietary copper uptake. SOD activity was reduced by midgut PSN knockdown, and these flies were sensitive to the superoxide-inducing chemical paraquat. These data support presenilin being needed for dietary copper uptake in the gut and so impacting on SOD activity and tolerance to oxidative stress. These results are consistent with previous studies of mammalian presenilins, supporting a conserved role for these proteins in mediating copper uptake.

  10. Grain Refinement of Permanent Mold Cast Copper Base Alloys

    Energy Technology Data Exchange (ETDEWEB)

    M.Sadayappan; J.P.Thomson; M.Elboujdaini; G.Ping Gu; M. Sahoo

    2005-04-01

    Grain refinement is a well established process for many cast and wrought alloys. The mechanical properties of various alloys could be enhanced by reducing the grain size. Refinement is also known to improve casting characteristics such as fluidity and hot tearing. Grain refinement of copper-base alloys is not widely used, especially in sand casting process. However, in permanent mold casting of copper alloys it is now common to use grain refinement to counteract the problem of severe hot tearing which also improves the pressure tightness of plumbing components. The mechanism of grain refinement in copper-base alloys is not well understood. The issues to be studied include the effect of minor alloy additions on the microstructure, their interaction with the grain refiner, effect of cooling rate, and loss of grain refinement (fading). In this investigation, efforts were made to explore and understand grain refinement of copper alloys, especially in permanent mold casting conditions.

  11. Comparison of metal-binding strength between methionine and cysteine residues: Implications for the design of metal-binding motifs in proteins.

    Science.gov (United States)

    Krishna Deepak, R N V; Chandrakar, Brijesh; Sankararamakrishnan, Ramasubbu

    2017-05-01

    Metals play vital role in various physiological processes and are bound to biomolecules. Although cysteine sulfur is more frequently found as metal-binding ligand, methionine prefers to occur in copper-binding motifs of some proteins. To address methionine's lower preference in copper-binding sites in comparison to cysteine, we have considered copper-binding motifs (His-Cys-His-Met) from seven different high-resolution protein structures. We performed quantum chemical calculations to find out the strength of interactions between sulfur and metal ion in both Met and Cys residues. In the case of Cys, both neutral (CysH) and the deprotonated form (Cys - ) were considered. We used two different levels of theory (B3LYP and M06-2X) and the model compounds methyl propyl sulfide, ethanethiol and ethanethiolate were used to represent Met, CysH and Cys - respectively. To compare the metal-binding strength, we mutated Met in silico to CysH/Cys - and performed the calculations. We also carried out calculations with wild-type Cys present in the same metal-binding motif. On average, interactions of Met with copper ion are stronger by 13-35kcal/mol compared to CysH. However, Cys - interactions with copper is stronger than that of Met by ~250kcal/mol. We then considered the entire metal-binding motif with four residues and calculated the interaction energies with the copper ion. We also considered Met→Cys - mutation in the motif and repeated the calculations. Interaction of the wild-type motif with the copper ion is ~160kcal/mol weaker than that of mutated motif. Our studies suggest the factors that could explain why Met is not as frequently observed as Cys in the metal-binding motifs. Results of these studies will help in designing metal-binding motifs in proteins with varying interaction strengths. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Thermodynamic data for copper. Implications for the corrosion of copper under repository conditions

    Energy Technology Data Exchange (ETDEWEB)

    Puigdomenech, I. [Royal Inst. of Tech., Stockholm (Sweden); Taxen, C. [Swedish Corrosion Inst., Stockholm (Sweden)

    2000-08-01

    The stability of copper canisters has a central role in the safety concept for the planned nuclear spent fuel repository in Sweden. The corrosion of copper canisters will be influenced by the chemical and physical environment in the near-field of the repository, and thermodynamic equilibrium calculations provide the basis for understanding this system. Thermodynamic data have been selected in this work for solids and aqueous species in the system: Cu - H{sub 2}O - H{sup +} - H{sub 2} - F{sup -} - Cl{sup -} - S{sup 2-} - SO{sub 4}{sup 2-} - NO{sub 3}{sup -} - NO{sub 2}{sup -} - NH{sub 4}{sup +} PO{sub 4}{sup 3-} - CO{sub 3}{sup 2+} . For some reactions and compounds, for which no experimental information on temperature effects was available, entropy and heat capacity values have been estimated. The compiled data were used to calculate thermodynamic equilibria for copper systems up to 100 deg C. The stability of copper in contact with granitic groundwaters has been illustrated using chemical equilibrium diagrams, with he following main conclusions: Dissolved sulphide and O{sub 2} in groundwater are the most damaging components for copper corrosion. If available, HS{sup -} will react quantitatively with copper to form a variety of sulphides. However, sulphide concentrations in natural waters are usually low, because it forms sparingly soluble solids with transition metals, including Fe(II), which is wide-spread in reducing environments. Chloride can affect negatively copper corrosion. High concentrations (e.g., [Cl{sup -}]TOT > 60 g/l) may be unfavourable for the general corrosion of copper in combination with in the following circumstances: Low pH (< 4 at 25 deg C, or < 5 at 100 deg C). The presence of other oxidants than H{sup +}. The negative effects of Cl{sup -} are emphasised at higher temperatures. The chloride-enhancement of general corrosion may be beneficial for localised corrosion: pitting and stress corrosion cracking. The concept of redox potential, E

  13. Copper uptake across rainbow trout gills: mechanisms of apical entry

    DEFF Research Database (Denmark)

    Grosell, Martin Hautopp; Wood, C. M.

    2002-01-01

    Copper, Homeostasis, sodium uptake, copper/sodium interactions, gill, rainbow trout, Oncorhynchus mykiss......Copper, Homeostasis, sodium uptake, copper/sodium interactions, gill, rainbow trout, Oncorhynchus mykiss...

  14. The Role of Copper in Neurodegenerative Disease

    Science.gov (United States)

    Rose, Francis M.

    My research concerns the fundamental atomistic mechanisms of neurodegenerative diseases and the methodologies by which they may be discerned. This thesis consists of three primary parts. The introductory material is the raison d'etre for this work and a critical overview of the specific physics, mathematics and algorithms used in this research. The methods are presented along with specific details in order to facilitate future replication and enhancement. With the groundwork of mechanisms and methods out of the way, we then explore a nouveau atomistic mechanism describing the onset of Parkinson's disease, a disease that has been closely linked to misfolded metalloproteins. Further exploration of neurodegeneration takes place in the following chapter, where a remedial approach to Alzheimer's disease via a simulated chelation of a metalloprotein is undertaken. Altogether, the methods and techniques applied here allow for simulated exploration of both the atomistic mechanisms of neurodegeneration and their potential remediation strategies. The beginning portion of the research efforts explore protein misfolding dynamics in the presence a copper ion. Misfolding of the human alpha-synuclein (aS) protein has been implicated as a central constituent in neurodegenerative disease. In Parkinson's disease (PD) in particular, aS is thought to be the causative participant when found concentrated into neuritic plaques. Here we propose a scenario involving the metal ion Cu2+ as the protein misfolding initiator of fibrillized aS, the chief component of neuritic plaques. From experimental results we know these misfolded proteins have a rich beta--sheet signature, a marker that we reproduce with our simulated model. This model identifies a process of structural modifications to a natively unfolded alpha-synuclein resulting in a partially folded intermediate with a well defined nucleation site. It serves as a precursor to the fully misfolded protein. Understanding the nucleation

  15. Room temperature fatigue behavior of OFHC copper and CuAl25 specimens of two sizes

    DEFF Research Database (Denmark)

    Singhal, A.; Stubbins, J.F.; Singh, B.N.

    1994-01-01

    requiring an understanding of their fatigue behavior.This paper describes the room temperature fatigue behavior of unirradiated OFHC (oxygen-free high-conductivity) copper and CuAl25 (copper strengthened with a 0.25% atom fraction dispersion of alumina). The response of two fatigue specimen sizes to strain......Copper and its alloys are appealing for application in fusion reactor systems for high heat flux components where high thermal conductivities are critical, for instance, in divertor components. The thermal and mechanical loading of such components will be, at least in part, cyclic in nature, thus...

  16. Competitive sorption and desorption of heavy metals by individual soil components

    International Nuclear Information System (INIS)

    Covelo, E.F.; Vega, F.A.; Andrade, M.L.

    2007-01-01

    Knowledge of sorption and desorption of heavy metals by individual soil components should be useful for modelling the behaviour of soils of arbitrary composition when contaminated by heavy metals, and for designing amendments increasing the fixation of heavy metals by soils polluted by these species. In this study the competitive sorption and desorption of Cd, Cr, Cu, Ni, Pb and Zn by humified organic matter, Fe and Mn oxides, kaolinite, vermiculite and mica were investigated. Due to the homogeneity of the sorbents, between-metal competition for binding sites led to their preferences for one or another metal being much more manifest than in the case of whole soils. On the basis of k d100 values (distribution coefficients calculated in sorption-desorption experiments in which the initial sorption solution contained 100 mg L -1 of each metal), kaolinite and mica preferentially sorbed and retained chromium; vermiculite, copper and zinc; HOM, Fe oxide and Mn oxide, lead (HOM and Mn oxide also sorbed and retained considerable amounts of copper). Mica only retained sorbed chromium, Fe oxide sorbed cadmium and lead, and kaolinite did not retain sorbed copper. The sorbents retaining the greatest proportions of sorbed metals were vermiculite and Mn oxide, but the ratios of k d100 values for retention and sorption suggest that cations were least reversibly bound by Mn oxide, and most reversibly by vermiculite

  17. Studies on zinc and copper ion in relation to wound healing in male ...

    African Journals Online (AJOL)

    Wound healing has been shown to depend upon the availability of appropriate trace elements like copper and zinc which serve as enzyme cofactors and structural components in tissue repair. This study aims at evaluating the distribution of zinc and copper found in the hair as well as skin during epidermal wound healing.

  18. Speciation study in the sulfamethoxazole-copper-pH-soil system: implications for retention prediction.

    Science.gov (United States)

    Morel, Marie-Christine; Spadini, Lorenzo; Brimo, Khaled; Martins, Jean M F

    2014-05-15

    Sulfamethoxazole (SMX) is a persistent sulfonamide antibiotic drug used in the veterinary and human medical sectors and is widely detected in natural waters. To better understand the reactive transport of this antibiotic in soil, the speciation of the SMX-Cu(II)-H(+) system in solution and the combined sorption of these components in a natural vineyard soil were investigated by acid-base titrimetry and infrared spectroscopy. Cu(II) is considered to represent a strongly complexing trace element cation (such as Cd(2+), Zn(2+), Pb(2+), Ni(2+), etc.) in comparison to more prevalent but more weakly binding cations (such as Ca(2+) and Mg(2+)). Titrimetric studies showed that, relative to other antibiotics, such as tetracycline, SMX is a weak copper chelating agent and a weak soil sorbent at the soil pH (pH6). However, the sorption of SMX in soil increases strongly (by a factor of 6) in the presence of copper. This finding strongly supports the hypothetical formation of ternary SMX-Cu-soil complexes, especially considering that copper is dominantly sorbed in a state at pH6. The data were successfully modelled with PhreeqC assuming the existence of binary and ternary surface complexes in equilibrium with aqueous Cu, SMX and Cu-SMX complexes. It is thought that other strongly complexing cations present on the surface of reactive organic and mineral soil phases, such as Cd(II), Ni(II), Zn(II), Pb(II), Fe(II/III), Mn(II/IV) and Al(III), affect the solid/solution partitioning of SMX. This study thus suggests that surface-adsorbed cations significantly increase the sorption of SMX. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Multilevel cycle of anthropogenic copper.

    Science.gov (United States)

    Graedel, T E; van Beers, D; Bertram, M; Fuse, K; Gordon, R B; Gritsinin, A; Kapur, A; Klee, R J; Lifset, R J; Memon, L; Rechberger, H; Spatari, S; Vexler, D

    2004-02-15

    A comprehensive contemporary cycle for stocks and flows of copper is characterized and presented, incorporating information on extraction, processing, fabrication and manufacturing, use, discard, recycling, final disposal, and dissipation. The analysis is performed on an annual basis, ca. 1994, at three discrete governmental unit levels--56 countries or country groups that together comprise essentially all global anthropogenic copper stocks and flows, nine world regions, and the planet as a whole. Cycles for all of these are presented and discussed, and a "best estimate" global copper cycle is constructed to resolve aggregation discrepancies. Among the most interesting results are (1) transformation rates and recycling rates in apparently similar national economies differ by factors of two or more (country level); (2) the discard flows that have the greatest potential for copper recycling are those with low magnitude flows but high copper concentrations--electronics, electrical equipment, and vehicles (regional level); (3) worldwide, about 53% of the copper that was discarded in various forms was recovered and reused or recycled (global level); (4) the highest rate of transfer of discarded copper to repositories is into landfills, but the annual amount of copper deposited in mine tailings is nearly as high (global level); and (5) nearly 30% of copper mining occurred merely to replace copper that was discarded. The results provide a framework for similar studies of other anthropogenic resource cycles as well as a basis for supplementary studies in resource stocks, industrial resource utilization, waste management, industrial economics, and environmental impacts.

  20. Ergothioneine prevents copper-induced oxidative damage to DNA and protein by forming a redox-inactive ergothioneine-copper complex.

    Science.gov (United States)

    Zhu, Ben-Zhan; Mao, Li; Fan, Rui-Mei; Zhu, Jun-Ge; Zhang, Ying-Nan; Wang, Jing; Kalyanaraman, Balaraman; Frei, Balz

    2011-01-14

    Ergothioneine (2-mercaptohistidine trimethylbetaine) is a naturally occurring amino acid analogue found in up to millimolar concentrations in several tissues and biological fluids. However, the biological functions of ergothioneine remain incompletely understood. In this study, we investigated the role of ergothioneine in copper-induced oxidative damage to DNA and protein, using two copper-containing systems: Cu(II) with ascorbate and Cu(II) with H(2)O(2) [0.1 mM Cu(II), 1 mM ascorbate, and 1 mM H(2)O(2)]. Oxidative damage to DNA and bovine serum albumin was measured as strand breakage and protein carbonyl formation, respectively. Ergothioneine (0.1-1.0 mM) provided strong, dose-dependent protection against oxidation of DNA and protein in both copper-containing systems. In contrast, only limited protection was observed with the purported hydroxyl radical scavengers, dimethyl sulfoxide and mannitol, even at concentrations as high as 100 mM. Ergothioneine also significantly inhibited copper-catalyzed oxidation of ascorbate and competed effectively with histidine and 1,10-phenanthroline for binding of cuprous copper, but not cupric copper, as demonstrated by UV-visible and low-temperature electron spin resonance techniques. We conclude that ergothioneine is a potent, natural sulfur-containing antioxidant that prevents copper-dependent oxidative damage to biological macromolecules by forming a redox-inactive ergothioneine-copper complex.

  1. and copper(II)

    Indian Academy of Sciences (India)

    Unknown

    that the imidazolate-bridged complex is stable over the pH-range 7⋅15–10⋅0. .... copper(II) complex. The observed room temperature magnetic moments are around. 1⋅79 BM, in agreement with a one-spin (S = 1/2) system. 3.2 EPR studies .... (SK) thanks the Council of Scientific & Industrial Research, New Delhi for an.

  2. Copper Pyrimidine based MOFs

    Indian Academy of Sciences (India)

    Cl..Cu.. interactions but restricted ..Cu..N N..Cu interacations. Supramolecular isomers of Br and I are reported for the first time in this paper. [Cu2I(pdz)X2]. Figure S18. Self assembly of the simultaneous presence of tecton {Cu(sol)3X} and {Cu(pdz)(sol)2X} result in [Cu2I(pdz)X2]. 1. Table S3. Copper Pyrimidine based MOFs ...

  3. Native copper as a natural analogue for copper canisters

    International Nuclear Information System (INIS)

    Marcos, N.

    1989-12-01

    This paper discusses the occurrence of native copper as found in geological formations as a stability analogue of copper canisters that are planned to be used for the disposal of spent nuclear fuel in the Finnish bedrock. A summary of several publications on native copper occurrences is presented. The present geochemical and geohydrological conditions in which copper is met with in its metallic state show that metallic copper is stable in a wide range of temperatures. At low temperatures native copper is found to be stable where groundwater has moderate pH (about 7), low Eh (< +100 mV), and low total dissolved solids, especially chloride. Microscopical and microanalytical studies were carried out on a dozen of rock samples containing native copper. The results reveal that the metal shows no significant alteration. Only the surface of copper grains is locally coated. In the oldest samples there exist small corrosion cracks; the age of the oldest samples is over 1,000 million years. A review of several Finnish groundwater studies suggests that there are places in Finland where the geohydrological conditions are favourable for native copper stability. (orig.)

  4. Preferred sites and pathways for electron transfer in blue copper proteins

    DEFF Research Database (Denmark)

    Farver, O; Pecht, I

    1988-01-01

    of where and how electrons are transferred to and from the copper-ion have been investigated. One experimental approach developed in order to pursue these problems is that of reductively labeling several representative, yet structurally distinct blue single copper proteins; azurin, plastocyanin......, and stellacyanin with chromium ions. In all three cases, a substitution inert Cr(III)-adduct is formed when the oxidized protein is reduced by Cr(II)ag ions. In azurin, Cr(III) binds to the Glu-91 carboxylate approximately 10 A from the copper center. In both plastocyanin and stellacyanin the Cr(III) label is most...... probably also coordinated to carboxylate groups, present in plastocyanin, and in stellacyanin 12 A and 6 A, respectively, from the copper center. The salient feature emerging from examination of the three copper proteins is that a pi-facilitated electron transfer (E.T.) pathway may be operative; in azurin...

  5. A Molecular Mechanism for Copper Transportation to Tyrosinase That Is Assisted by a Metallochaperone, Caddie Protein*

    Science.gov (United States)

    Matoba, Yasuyuki; Bando, Naohiko; Oda, Kosuke; Noda, Masafumi; Higashikawa, Fumiko; Kumagai, Takanori; Sugiyama, Masanori

    2011-01-01

    The Cu(II)-soaked crystal structure of tyrosinase that is present in a complex with a protein, designated “caddie,” which we previously determined, possesses two copper ions at its catalytic center. We had identified two copper-binding sites in the caddie protein and speculated that copper bound to caddie may be transported to the tyrosinase catalytic center. In our present study, at a 1.16–1.58 Å resolution, we determined the crystal structures of tyrosinase complexed with caddie prepared by altering the soaking time of the copper ion and the structures of tyrosinase complexed with different caddie mutants that display little or no capacity to activate tyrosinase. Based on these structures, we propose a molecular mechanism by which two copper ions are transported to the tyrosinase catalytic center with the assistance of caddie acting as a metallochaperone. PMID:21730070

  6. Serpula lacrymans, The Dry Rot Fungus and Tolerance Towards Copper-Based Wood Preservatives

    DEFF Research Database (Denmark)

    Hastrup, Anne Christine Steenkjær; Jensen, Bo; Clausen, Carol

    2005-01-01

    -rot fungi is thought to be due in part to oxalic acid production and accumulation. Oxalic acid has been implicated in copper tolerance by the formation of copper oxalate crystals. Twelve isolates of the dry rot fungus, S. lacrymans and four other brown rot species were evaluated for weight loss on wood......Serpula lacrymans (Wulfen : Fries) Schröter, the dry rot fungus, is considered the most (Wulfen : Fries) Schröterthe dry rot fungus, is considered the most economically important wood decay fungus in temperate regions of the world i.e. northern Europe, Japan and Australia. Previously copper based...... wood preservatives were the most commonly used preservatives for pressure treatment of wood for building constructions. Because of a suspicion about tolerance toward copper components, a soil block test was undertaken to clarify the effect of two copper based preservatives, copper citrate and ACQ...

  7. Sequential memory: Binding dynamics

    Science.gov (United States)

    Afraimovich, Valentin; Gong, Xue; Rabinovich, Mikhail

    2015-10-01

    Temporal order memories are critical for everyday animal and human functioning. Experiments and our own experience show that the binding or association of various features of an event together and the maintaining of multimodality events in sequential order are the key components of any sequential memories—episodic, semantic, working, etc. We study a robustness of binding sequential dynamics based on our previously introduced model in the form of generalized Lotka-Volterra equations. In the phase space of the model, there exists a multi-dimensional binding heteroclinic network consisting of saddle equilibrium points and heteroclinic trajectories joining them. We prove here the robustness of the binding sequential dynamics, i.e., the feasibility phenomenon for coupled heteroclinic networks: for each collection of successive heteroclinic trajectories inside the unified networks, there is an open set of initial points such that the trajectory going through each of them follows the prescribed collection staying in a small neighborhood of it. We show also that the symbolic complexity function of the system restricted to this neighborhood is a polynomial of degree L - 1, where L is the number of modalities.

  8. Jet-printed copper metallization

    Science.gov (United States)

    Hong, Cheong Min

    Macroelectronics is a technology for making electronic circuits over very large areas at low cost. Flat panel displays, sensor arrays, and thin film solar cells are examples of macroelectronics. Crucial to the success of this new technology is the development of inexpensive electronic processes, materials, and devices. Direct printing techniques, which eliminate processing steps and save device and process materials, are the key to high volume and high throughput manufacturing. Copper metallization has been receiving increasing attention in both microelectronics and macroelectronics. Copper has high conductivity, density, melting point, heat capacity, and thermal conductivity. However, copper is also hard to dry etch. For these reasons we have developed and demonstrated a directly printed copper source/drain metallization technique and applied it to the fabrication of hydrogenated amorphous silicon (a-Si:H) thin film transistors (TFTs). The maximum process temperature of 200°C is compatible with conventional active matrix liquid crystal display (AMLCD) technology. In this dissertation, we show the process of depositing copper films by jet printing. We discuss the preparation and the properties of the copper precursor material used in the jet printing. We survey the conversion process from copper precursor to copper under varying processing conditions. The resulting copper film is probed for its physical, electrical, and mechanical properties. To demonstrate the feasibility of the jet printing technique, we print copper source/drain contacts for a-Si:H TFTs. The photolithography-free TFT fabrication process uses the printed xerographic toner technique developed earlier in this laboratory. We show that functional TFTs can be made with printed copper source and drain contacts. The jet printing of copper contacts represents a further step toward an all-printed thin film transistor technology.

  9. Designing, structural elucidation, comparison of DNA binding, cleavage, radical scavenging activity and anticancer activity of copper(I) complex with 5-dimethyl-2-phenyl-4-[(pyridin-2-ylmethylene)-amino]-1,2-dihydro-pyrazol-3-one Schiff base ligand.

    Science.gov (United States)

    Sathiyaraj, Subbaiyan; Sampath, Krishnan; Butcher, Ray J; Pallepogu, Raghavaiah; Jayabalakrishnan, Chinnasamy

    2013-06-01

    A novel copper(I) Schiff base complex has been synthesized and fully characterized by spectral, analytical and structural modes. Single crystal X-ray diffraction studies revealed that the copper(I) complex [CuCl(PPh3)L] has a distorted tetrahedral geometry around the central copper(I) ion. The interaction of the ligand and the complex with CT-DNA has been explored by absorption titration method which revealed that the compounds could interact with CT-DNA through intercalation. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 DNA. The antioxidative properties showed that the copper(I) complex has a strong radical-scavenging potency than ligands. Further the cytotoxic effect of the compounds examined on cancerous cell lines showed that the complex exhibited substantial anticancer activity. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  10. Other components

    International Nuclear Information System (INIS)

    Anon.

    1993-01-01

    This chapter includes descriptions of electronic and mechanical components which do not merit a chapter to themselves. Other hardware requires mention because of particularly high tolerance or intolerance of exposure to radiation. A more systematic analysis of radiation responses of structures which are definable by material was given in section 3.8. The components discussed here are field effect transistors, transducers, temperature sensors, magnetic components, superconductors, mechanical sensors, and miscellaneous electronic components

  11. Physical Properties of Copper Based MMC Strengthened with Alumina

    Directory of Open Access Journals (Sweden)

    Kaczmar J. W.

    2014-06-01

    Full Text Available The aim of this work is the development of Cu-Al2O3 composites of copper Cu-ETP matrix composite materials reinforced by 20 and 30 vol.% Al2O3 particles and study of some chosen physical properties. Squeeze casting technique of porous compacts with liquid copper was applied at the pressure of 110 MPa. Introduction of alumina particles into copper matrix affected on the significant increase of hardness and in the case of Cu-30 vol. % of alumina particles to 128 HBW. Electrical resistivity was strongly affected by the ceramic alumina particles and addition of 20 vol. % of particles caused diminishing of electrical conductivity to 20 S/m (34.5% IACS. Thermal conductivity tests were performed applying two methods and it was ascertained that this parameter strongly depends on the ceramic particles content, diminishing it to 100 Wm-1K-1 for the composite material containing 30 vol.% of ceramic particles comparing to 400 Wm-1K-1 for the unreinforced copper. Microstructural analysis was carried out using SEM microscopy and indicates that Al2O3 particles are homogeneously distributed in the copper matrix. EDS analysis shows remains of silicon on the surface of ceramic particles after binding agent used during preparation of ceramic preforms.

  12. Biosorption of copper and lead ions by waste beer yeast.

    Science.gov (United States)

    Han, Runping; Li, Hongkui; Li, Yanhu; Zhang, Jinghua; Xiao, Huijun; Shi, Jie

    2006-10-11

    Locally available waste beer yeast, a byproduct of brewing industry, was found to be a low cost and promising adsorbent for adsorbing copper and lead ions from wastewater. In this work, biosorption of copper and lead ions on waste beer yeast was investigated in batch mode. The equilibrium adsorptive quantity was determined to be a function of the solution pH, contact time, beer yeast concentration, salt concentration and initial concentration of copper and lead ions. The experimental results were fitted well to the Langmuir and Freundlich model isotherms. According to the parameters of Langmuir isotherm, the maximum biosorption capacities of copper and lead ions onto beer yeast were 0.0228 and 0.0277 mmol g(-1) at 293 K, respectively. The negative values of the standard free energy change (DeltaG degrees ) indicate spontaneous nature of the process. Competitive biosorption of two metal ions was investigated in terms of sorption quantity. The amount of one metal ion adsorbed onto unit weight of biosorbent (q(e)) decreased with increasing the competing metal ion concentration. The binding capacity for lead is more than for copper. Ion exchange is probably one of the main mechanism during adsorptive process.

  13. Electrodeposition and Properties of Copper Layer on NdFeB Device

    Directory of Open Access Journals (Sweden)

    LI Yue

    2017-06-01

    Full Text Available To decrease the impact of the regular Ni/Cu/Ni coating on the magnetic performance of sintered NdFeB device, alkaline system of HEDP complexing agent was applied to directly electro-deposit copper layer on NdFeB matrix, then nickel layer was electrodeposited on the copper layer and Cu/Ni coating was finally obtained to replace the regular Ni/Cu/Ni coating. The influence of concentration of HEDP complexing agent on deposition course was tested by electrochemical testing; morphology of copper layer was characterized by SEM, XRD and TEM; the binding force of copper layer and the thermal reduction of magnetic of NdFeB caused by electrodeposited coating were respectively explored through the thermal cycle test and thermal demagnetization test. The results show that the concentration of HEDP has great impact on the deposition overpotential of copper. In the initial electrodepositing stage, copper particles precipitate at the grain boundaries of NdFeB magnets with a preferred (111 orientation. The copper layer is compact and has enough binding force with the NdFeB matrix to meet the requirements in SJ 1282-1977. Furthermore, the thermal demagnetization loss rate of the sintered NdFeB with the protection of Cu/Ni coating is significantly less than that with the protection of Ni/Cu/Ni coating.

  14. Age-related cellular copper dynamics in the fungal ageing model Podospora anserina and in ageing human fibroblasts.

    Directory of Open Access Journals (Sweden)

    Christian Q Scheckhuber

    Full Text Available In previous investigations an impact of cellular copper homeostasis on ageing of the ascomycete Podospora anserina has been demonstrated. Here we provide new data indicating that mitochondria play a major role in this process. Determination of copper in the cytosolic fraction using total reflection X-ray fluorescence spectroscopy analysis and eGfp reporter gene studies indicate an age-related increase of cytosolic copper levels. We show that components of the mitochondrial matrix (i.e. eGFP targeted to mitochondria become released from the organelle during ageing. Decreasing the accessibility of mitochondrial copper in P. anserina via targeting a copper metallothionein to the mitochondrial matrix was found to result in a switch from a copper-dependent cytochrome-c oxidase to a copper-independent alternative oxidase type of respiration and results in lifespan extension. In addition, we demonstrate that increased copper concentrations in the culture medium lead to the appearance of senescence biomarkers in human diploid fibroblasts (HDFs. Significantly, expression of copper-regulated genes is induced during in vitro ageing in medium devoid of excess copper suggesting that cytosolic copper levels also increase during senescence of HDFs. These data suggest that the identified molecular pathway of age-dependent copper dynamics may not be restricted to P. anserina but may be conserved from lower eukaryotes to humans.

  15. Age-Related Cellular Copper Dynamics in the Fungal Ageing Model Podospora anserina and in Ageing Human Fibroblasts

    Science.gov (United States)

    Scheckhuber, Christian Q.; Grief, Jürgen; Boilan, Emmanuelle; Luce, Karin; Debacq-Chainiaux, Florence; Rittmeyer, Claudia; Gredilla, Ricardo; Kolbesen, Bernd O.; Toussaint, Olivier; Osiewacz, Heinz D.

    2009-01-01

    In previous investigations an impact of cellular copper homeostasis on ageing of the ascomycete Podospora anserina has been demonstrated. Here we provide new data indicating that mitochondria play a major role in this process. Determination of copper in the cytosolic fraction using total reflection X-ray fluorescence spectroscopy analysis and eGfp reporter gene studies indicate an age-related increase of cytosolic copper levels. We show that components of the mitochondrial matrix (i.e. eGFP targeted to mitochondria) become released from the organelle during ageing. Decreasing the accessibility of mitochondrial copper in P. anserina via targeting a copper metallothionein to the mitochondrial matrix was found to result in a switch from a copper-dependent cytochrome-c oxidase to a copper-independent alternative oxidase type of respiration and results in lifespan extension. In addition, we demonstrate that increased copper concentrations in the culture medium lead to the appearance of senescence biomarkers in human diploid fibroblasts (HDFs). Significantly, expression of copper-regulated genes is induced during in vitro ageing in medium devoid of excess copper suggesting that cytosolic copper levels also increase during senescence of HDFs. These data suggest that the identified molecular pathway of age-dependent copper dynamics may not be restricted to P. anserina but may be conserved from lower eukaryotes to humans. PMID:19305496

  16. Binding of (/sup 3/H)imipramine to human platelet membranes with compensation for saturable binding to filters and its implication for binding studies with brain membranes

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, O.M.; Wood, K.M.; Williams, D.C.

    1984-08-01

    Apparent specific binding of (/sup 3/H)imipramine to human platelet membranes at high concentrations of imipramine showed deviation from that expected of a single binding site, a result consistent with a low-affinity binding site. The deviation was due to displaceable, saturable binding to the glass fibre filters used in the assays. Imipramine, chloripramine, desipramine, and fluoxetine inhibited binding to filters whereas 5-hydroxytryptamine and ethanol were ineffective. Experimental conditions were developed that eliminated filter binding, allowing assay of high- and low-affinity binding to membranes. Failure to correct for filter binding may lead to overestimation of binding parameters, Bmax and KD for high-affinity binding to membranes, and may also be misinterpreted as indicating a low-affinity binding component in both platelet and brain membranes. Low-affinity binding (KD less than 2 microM) of imipramine to human platelet membranes was demonstrated and its significance discussed.

  17. Reversible Redox Activity in Multicomponent Metal-Organic Frameworks Constructed from Trinuclear Copper Pyrazolate Building Blocks.

    Science.gov (United States)

    Tu, Binbin; Pang, Qingqing; Xu, Huoshu; Li, Xiaomin; Wang, Yulin; Ma, Zhen; Weng, Linhong; Li, Qiaowei

    2017-06-14

    Inorganic functionalization of metal-organic frameworks (MOFs), such as incorporation of multiple inorganic building blocks with distinct metals into one structure and further modulation of the metal charges, endows the porous materials with significant properties toward their applications in catalysis. In this work, by an exploration of the role of 4-pyrazolecarboxylic acid (H 2 PyC) in the formation of trinuclear copper pyrazolate as a metalloligand in situ, four new MOFs with multiple components in order were constructed through one-pot synthesis. This metalloligand strategy provides multicomponent MOFs with new topologies (tub for FDM-4 and tap for FDM-5) and is also compatible with a second organic linker for cooperative construction of complex MOFs (1,4-benzenedicarboxylic acid for FDM-6 and 2,6-naphthalenedicarboxylic acid for FDM-7). The component multiplicity of these MOFs originates from PyC's ability to separate Cu and Zn on the basis of their differentiated binding affinities toward pyrazolate and carboxylate. These MOFs feature reversible and facile redox transformations between Cu I 3 (PyC) 3 and Cu II 3 (μ-OH)(PyC) 3 (OH) 3 without altering the connecting geometries of the units, thus further contributing to the significant catalytic activities in the oxidation of CO and aromatic alcohols and the decomposition of H 2 O 2 . This study on programming multiple inorganic components into one framework and modulating their electronic structures is an example of functionalizing the inorganic units of MOFs with a high degree of control.

  18. Nickel, copper and cobalt coalescence in copper cliff converter slag

    Directory of Open Access Journals (Sweden)

    Wolf A.

    2016-01-01

    Full Text Available The aim of this investigation is to assess the effect of various additives on coalescence of nickel, copper and cobalt from slags generated during nickel extraction. The analyzed fluxes were silica and lime while examined reductants were pig iron, ferrosilicon and copper-silicon compound. Slag was settled at the different holding temperatures for various times in conditions that simulated the industrial environment. The newly formed matte and slag were characterized by their chemical composition and morphology. Silica flux generated higher partition coefficients for nickel and copper than the addition of lime. Additives used as reducing agents had higher valuable metal recovery rates and corresponding partition coefficients than fluxes. Microstructural studies showed that slag formed after adding reductants consisted of primarily fayalite, with some minute traces of magnetite as the secondary phase. Addition of 5 wt% of pig iron, ferrosilicon and copper-silicon alloys favored the formation of a metallized matte which increased Cu, Ni and Co recoveries. Addition of copper-silicon alloys with low silicon content was efficient in copper recovery but coalescence of the other metals was low. Slag treated with the ferrosilicon facilitated the highest cobalt recovery while copper-silicon alloys with silicon content above 10 wt% resulted in high coalescence of nickel and copper, 87 % and 72 % respectively.

  19. Spectrographic determination of impurities in copper and copper oxide

    International Nuclear Information System (INIS)

    Sabato, S.F.; Lordello, A.R.

    1990-11-01

    An emission spectrographic method for the determination of Al, Bi, Ca, Cd, Cr, Fe, Ge, Mg, Mn, Mo, Ni, Pb, Sb, Si, Sn and Zn in copper and copper oxide is described. Two mixtures (Graphite and ZnO: graphite and GeO sub(2)) were used as buffers. The standard deviation lies around 10%. (author)

  20. Magnesium, zinc and copper estimation in children with attention ...

    African Journals Online (AJOL)

    Farida Elbaz

    2016-05-14

    May 14, 2016 ... magnesium and zinc levels (not copper) as regards the Cate- gory Completion and Conceptual component of the Wisconsin card sorting test (WCST). The WCST, relies upon a number of cognitive functions including attention, working memory, and visual processing. It measure frontal lobe dysfunction [20].

  1. High thermal load component

    International Nuclear Information System (INIS)

    Fuse, Toshiaki; Tachikawa, Nobuo.

    1996-01-01

    A cooling tube made of a pure copper is connected to the inner portion of an armour (heat resistant member) made of an anisotropic carbon/carbon composite (CFC) material. The CFC material has a high heat conductivity in longitudinal direction of fibers and has low conductivity in perpendicular thereto. Fibers extending in the armour from a heat receiving surface just above the cooling tube are directly connected to the cooling tube. A portion of the fibers extending from a heat receiving surface other than portions not just above the cooling tube is directly bonded to the cooling tube. Remaining fibers are disposed so as to surround the cooling tube. The armour and the cooling tube are soldered using an active metal flux. With such procedures, high thermal load components for use in a thermonuclear reactor are formed, which are excellent in a heat removing characteristic and hardly causes defects such as crackings and peeling. (I.N.)

  2. Copper vapor laser development for SILVA

    Science.gov (United States)

    Bettinger, Antoine; Neu, M.; Maury, J.; Chatelet, Jacques A.

    1993-05-01

    The recent developments of the components for high power Copper Vapor Laser (CVL) have been oriented towards four main goals: high quality laser beam, mainly for the CVL oscillators, increase of the extracted energy out of the amplifying stage, fully integrated and monolithic design for oscillator and amplifier, and extended lifetime and high reliability. A first step of this work, which is done under contract with CILAS (Compagnie Industrielle des Lasers) led to an injection seeded oscillator and a 100 Watt amplifier; the present step concerns development of a 400 Watts class amplifier.

  3. Copper (II) complexes with aroylhydrazones

    Indian Academy of Sciences (India)

    Copper(II) complexes with aroylhydrazones ... The coordination chemistry of copper(II) with tridentate aroylhydrazones is briefly discussed in this article. ... EPR spectroscopy and variable temperature magnetic susceptibility measurements have been used to reveal the nature of the coordination geometry and magnetic ...

  4. The Bauschinger Effect in Copper

    DEFF Research Database (Denmark)

    Pedersen, Ole Bøcker; Brown, L .M.; Stobbs, W. M.

    1981-01-01

    A study of the Bauschinger effect in pure copper shows that by comparison with dispersion hardened copper the effect is very small and independent of temperature. This suggests that the obstacles to flow are deformable. A simple composite model based on this principle accounts for the data semi...

  5. The involvement of vimentin in copper-induced regression of cardiomyocyte hypertrophy.

    Science.gov (United States)

    Li, Rui; Bourcy, Katherine; Wang, Tao; Sun, Miao; Kang, Y James

    2015-09-01

    Dietary copper supplementation reverses the pressure overload-induced cardiac hypertrophy. Activation of vascular endothelial growth factor receptor-1 (VEGFR-1) and cyclic guanosine monophosphate (cGMP)-dependent protein kinase-1 (PKG-1) is required for the regression. The present study was undertaken to determine the link between VEGFR-1 and PKG-1 in copper regression of cardiomyocyte hypertrophy. Human cardiac myocytes (HCM) or primary cultures of neonatal rat cardiomyocytes were exposed to phenylephrine (PE) at a final concentration of 100 μM for 48 h to induce cell hypertrophy. Copper sulfite was added to cultures of hypertrophic cardiomyocytes at a final concentration of 5 μM elemental copper and incubated for 24 h to reverse cell hypertrophy. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis identified a 56 kDa copper-binding protein, vimentin, which was co-immunoprecipitated with VEGFR-1 and PKG-1. Copper supplementation increased vimentin levels and enhanced PKG-1 activity. Gene silencing using siRNA targeting vimentin prevented copper-induced elevation of vimentin, depressed the activity of PKG-1, and blocked the copper-induced regression of cardiomyocyte hypertrophy. This study demonstrates that vimentin is critically involved in the VEGFR-1 mediated activation of the PKG-1 signaling pathway, leading to regression of cardiomyocyte hypertrophy.

  6. Electronic components

    CERN Document Server

    Colwell, Morris A

    1976-01-01

    Electronic Components provides a basic grounding in the practical aspects of using and selecting electronics components. The book describes the basic requirements needed to start practical work on electronic equipment, resistors and potentiometers, capacitance, and inductors and transformers. The text discusses semiconductor devices such as diodes, thyristors and triacs, transistors and heat sinks, logic and linear integrated circuits (I.C.s) and electromechanical devices. Common abbreviations applied to components are provided. Constructors and electronics engineers will find the book useful

  7. Component testing

    International Nuclear Information System (INIS)

    Hutchings, M.T.; Schofield, Peter; Seymour, W.A.J.

    1986-01-01

    A method for non-destructive testing of an industrial component to ascertain if it is a single crystal, and to find the crystal orientations of those parts of the component which are single crystals, involves irradiating the component with a monochromatic collimated neutron beam. Diffracted neutron beams are observed live by means of LiF/ZnS composite screen, an image intensifier and a television camera and screen. (author)

  8. Copper: From neurotransmission to neuroproteostasis

    Directory of Open Access Journals (Sweden)

    Carlos M Opazo

    2014-07-01

    Full Text Available Copper is critical for the Central Nervous System (CNS development and function. In particular, different studies have shown the effect of copper at brain synapses, where it inhibits Long Term Potentation (LTP and receptor pharmacology. Paradoxically, according to recent studies copper is required for a normal LTP response. Copper is released at the synaptic cleft, where it blocks glutamate receptors, which explain its blocking effects on excitatory neurotransmission. Our results indicate that copper also enhances neurotransmission through the accumulation of PSD95 protein, which increase the levels of AMPA receptors located at the plasma membrane of the post-synaptic density. Thus, our findings represent a novel mechanism for the action of copper, which may have implications for the neurophysiology and neuropathology of the CNS. These data indicate that synaptic configuration is sensitive to transient changes in transition metal homeostasis. Our results suggest that copper increases GluA1 subunit levels of the AMPA receptor through the anchorage of AMPA receptors to the plasma membrane as a result of PSD-95 accumulation. Here, we will review the role of copper on neurotransmission of CNS neurons. In addition, we will discuss the potential mechanisms by which copper could modulate neuronal proteostasis (neuroproteostasis in the CNS with focus in the Ubiquitin Proteasome System, which is particularly relevant to neurological disorders such Alzheimer’s disease (AD where copper and protein dyshomeostasis may contribute to neurodegeneration. An understanding of these mechanisms may ultimately lead to the development of novel therapeutic approaches to control metal and synaptic alterations observed in AD patients.

  9. Procurement model for copper and polymer electrical products

    Directory of Open Access Journals (Sweden)

    S. Sremac

    2013-10-01

    Full Text Available Procurement model for copper and polymer electrical products. Electrical cable structure (wire, insulation, filling and mantle is in accordance with the technical specifications of individual cable components in terms of the incorporated materials. Materials used in cable manufacture are copper, aluminum, rubber and polyvinyl chloride. One of the key issues in managing the flow of goods pertains to the timing of procurement. The combination of the two concepts can take advantage of individual strengths of fuzzy logic and neural networks in hybrid systems of homogeneous structure. The model has high practical significance, as, with minor modifications, it can be applied in any enterprise responsible for managing the goods flows.

  10. Unhindered copper uptake by glutaraldehyde-polyethyleneimine coatings in an artificial seawater model system with adsorbed swollen polysaccharides and competing ligand EDTA.

    Science.gov (United States)

    Kaur, Simarpreet; Kempson, Ivan M; Lindén, Johan B; Larsson, Mikael; Nydén, Magnus

    2017-02-01

    Shortly after a surface is submerged in the sea, a conditioning film is generally formed by adsorption of organic molecules, such as polysaccharides. This could affect transport of molecules and ions between the seawater and the surface. An artificial seawater model system was developed to understand how adsorbed polysaccharides impact copper binding by glutaraldehyde-crosslinked polyethyleneimine coatings. Coating performance was also determined when competed against copper-chelating EDTA. Polysaccharide adsorption and copper binding and distribution were investigated using advanced analytical techniques, including depth-resolved time-of-flight secondary ion mass spectroscopy, grazing incidence X-ray absorption near-edge spectroscopy, quartz crystal microbalance with dissipation monitoring and X-ray photoelectron spectroscopy. In artificial seawater, the polysaccharides adsorbed in a swollen state that copper readily penetrated and the glutaraldehyde-polyethyleneimine coatings outcompeted EDTA for copper binding. Furthermore, the depth distribution of copper species was determined with nanometre precision. The results are highly relevant for copper-binding and copper-releasing materials in seawater.

  11. Characterisation of the interactions between substrate, copper(II) complex and DNA and their role in rate acceleration in DNA-based asymmetric catalysis

    NARCIS (Netherlands)

    Draksharapu, Apparao; Boersma, Arnold J; Browne, Wesley R; Roelfes, Gerard

    2015-01-01

    Interactions of the azachalcone derived substrate Aza with copper(II) complexes in the presence and absence of st-DNA were studied in detail by UV/Vis absorption, EPR and Raman and (UV and vis) resonance Raman spectroscopies. The binding of Aza to the Lewis acidic copper(II) complexes, which results

  12. The Clp protease system is required for copper ion-dependent turnover of the PAA2/HMA8 copper transporter in chloroplasts.

    Science.gov (United States)

    Tapken, Wiebke; Kim, Jitae; Nishimura, Kenji; van Wijk, Klaas J; Pilon, Marinus

    2015-01-01

    The distribution of essential metal ions over subcellular compartments for use as cofactors requires control of membrane transporters. PAA2/HMA8 is a copper-transporting P1B -type ATPase in the thylakoid membrane, required for the maturation of plastocyanin. When copper is highly available to the plant this transporter is degraded, which implies the action of a protease. In order to identify the proteolytic machinery responsible for PAA2/HMA8 turnover in Arabidopsis, mutant lines defective in five different chloroplast protease systems were analyzed. Plants defective in the chloroplast caseinolytic protease (Clp) system were specifically impaired in PAA2/HMA8 protein turnover on media containing elevated copper concentrations. However, the abundance of a core Clp component was not directly affected by copper. Furthermore, the expression and activity of both cytosolic and chloroplast-localized superoxide dismutases (SODs), which are known to be dependent on copper, were not altered in the clp mutants, indicating that the loss of PAA2/HMA8 turnover in these lines was not caused by a lack of stromal copper. The results suggest that copper excess in the stroma triggers selection of the thylakoid-localized PAA2 transporter for degradation by the Clp protease, but not several other chloroplast proteases, and support a novel role for this proteolytic system in cellular copper homeostasis. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  13. Unexpected role of the copper transporter ATP7A in PDGF-induced vascular smooth

    Energy Technology Data Exchange (ETDEWEB)

    Ashino, T.; Varadarajan, S.; Urao, N.; Oshikawa, J.; Chen, G. -F.; Wang, H.; Huo, Y.; Finney, L.; Vogt, S.; McKinney, R. D.; Maryon, E. B.; Kaplan, J. H.; Ushio-Fukai, M.; Fukai, T. (Biosciences Division); ( XSD); ( PSC-USR); (Univ. of Illinois at Chicago); (Univ. of Minnesota)

    2010-09-09

    Copper, an essential nutrient, has been implicated in vascular remodeling and atherosclerosis with unknown mechanism. Bioavailability of intracellular copper is regulated not only by the copper importer CTR1 (copper transporter 1) but also by the copper exporter ATP7A (Menkes ATPase), whose function is achieved through copper-dependent translocation from trans-Golgi network (TGN). Platelet-derived growth factor (PDGF) promotes vascular smooth muscle cell (VSMC) migration, a key component of neointimal formation. To determine the role of copper transporter ATP7A in PDGF-induced VSMC migration. Depletion of ATP7A inhibited VSMC migration in response to PDGF or wound scratch in a CTR1/copper-dependent manner. PDGF stimulation promoted ATP7A translocation from the TGN to lipid rafts, which localized at the leading edge, where it colocalized with PDGF receptor and Rac1, in migrating VSMCs. Mechanistically, ATP7A small interfering RNA or CTR small interfering RNA prevented PDGF-induced Rac1 translocation to the leading edge, thereby inhibiting lamellipodia formation. In addition, ATP7A depletion prevented a PDGF-induced decrease in copper level and secretory copper enzyme precursor prolysyl oxidase (Pro-LOX) in lipid raft fraction, as well as PDGF-induced increase in LOX activity. In vivo, ATP7A expression was markedly increased and copper accumulation was observed by synchrotron-based x-ray fluorescence microscopy at neointimal VSMCs in wire injury model. These findings suggest that ATP7A plays an important role in copper-dependent PDGF-stimulated VSMC migration via recruiting Rac1 to lipid rafts at the leading edge, as well as regulating LOX activity. This may contribute to neointimal formation after vascular injury. Our findings provide insight into ATP7A as a novel therapeutic target for vascular remodeling and atherosclerosis.

  14. Studies on Ferrokinetics and Copper Metabolism in Various Malignant Tumors

    International Nuclear Information System (INIS)

    Kim, Yong Kyu

    1967-01-01

    Anemia is a usual finding in advanced malignant diseases. Various mechanisms were reported as to be involved in the development of anemia of this kind, and they may differ in individual cases. Tumor anemias may be due, for instance, to chronic blood loss, shortened life span of the red blood cells or a decreased hemopoiesis in the bone marrow. The serum iron and copper levels, total iron binding capacity, apparent half survival of 51 Cr-labelled red blood cells were measurement with the ferrokinetic studies using 59 Fe in 64 patients with various malignant tumors. Following were the results: 1) The serum iron levels were decreased in all cases. There existed no correlation between the serum iron levels and the severity of the diseases. 2) The serum copper levels were increased, particularly in lung cancer, rectal cancer, hepatoma and various sarcomas. There was also no correlation between the serum copper levels and the severity of the diseases. 3) The serum iron levels appeared to be inversely proportional to the serum copper levels. 4) The total iron binding capacities were within normal limits in all cases. There were also no correlations between the total iron binding capacities, serum iron levels and the severity of the diseases. 5) The patients could be classified according the ferrokinetic patterns, namely, that of iron deficiency anemia in 10 cases, that of refractory anemia in 6 cases, normal in 1 case and that of atypical abnormal in 9 cases. 6) Apparent half survival time of 51 Cr-labelled red blood cells were definitely shortened in half of the cases.

  15. Investigation of the chemical and electrochemical phenomena in the chemical mechanical planarization of copper

    Science.gov (United States)

    Wang, Ling

    uncoupled copper, tantalum and titanium electrodes were obtained in commercial slurry and solutions containing hydrogen peroxide and glycine, for assessing the polarity between copper and tantalum when forming a galvanic couple, as function of peroxide concentrations, solution pHs, and the impact of diluting the slurry on the galvanic interaction. Galvanic currents and mixed corrosion potentials were measured in tantalum-copper couples formed by short-circuiting the two specimen electrodes in a three-electrode cell through a potentiostat-based zero resistance ammeter, to verify the correlation between the polarity and the galvanic interactions and to assess the effects of solution composition and the tantalum-to-copper surface area ratio. The results showed that the material removal due to galvanic interaction under non-polishing conditions is negligibly small, but could be a potential issue during CMP, and either copper or tantalum barrier material could experience accelerated corrosion, depending on the solution composition. The galvanic interaction between copper and tantalum is sensitive to the solution composition. Acidic acetate/acetic acid buffer may transiently accelerate the galvanic corrosion of copper, while basic carbonate/bicarbonate buffer may transiently accelerate the galvanic corrosion of tantalum. Glycine promotes galvanic corrosion of copper. Hydrogen peroxide is the most effective component to exacerbate galvanic corrosion between copper and tantalum, with tantalum experiencing accelerated corrosion. Changing the surface area of tantalum, which has the more active corrosion, has a less significant effect on the galvanic corrosion than changing the surface areas of the copper, which has a more noble potential.

  16. Copper uptake and retention in liver parenchymal cells isolated from nutritionally copper-deficient rats

    NARCIS (Netherlands)

    Berg, G.J. van den; Goeij, J.J.M. de; Bock, I.; Gijbels, M.J.J.; Brouwer, A.; Lei, K.Y.; Hendruiks, H.F.J.

    1991-01-01

    Copper uptake and retention were studied in primary cultures of liver parenchymal cells isolated from copper-deficient rats. Male Sprague-Dawley rats were fed a copper-deficient diet (< 1 mg Cu/kg) for 10 wk. Copper-deficient rats were characterized by low copper concentrations in plasma and liver,

  17. Weldability of AISI 304 to copper by friction welding

    Energy Technology Data Exchange (ETDEWEB)

    Kirik, Ihsan [Batman Univ. (Turkey); Balalan, Zulkuf [Firat Univ., Elazig (Turkey)

    2013-06-01

    Friction welding is a solid-state welding method, which can join different materials smoothly and is excessively used in manufacturing industry. Friction welding method is commonly used in welding applications of especially cylindrical components, pipes and materials with different properties, for which other welding methods remain incapable. AISI 304 stainless steel and a copper alloy of 99.6 % purity were used in this study. This couple was welded in the friction welding machine. After the welding process, samples were analyzed macroscopically and microscopically, and their microhardness was measured. Tensile test was used to determine the bond strength of materials that were joined using the friction welding method. At the end of the study, it was observed that AISI 304 stainless steel and copper could be welded smoothly using the friction welding method and the bond strength is close to the tensile strength of copper. (orig.)

  18. The effect of neutron spectrum on the mechanical and physical properties of pure copper and copper alloys

    International Nuclear Information System (INIS)

    Fabritsiev, S.A.; Pokrovsky, A.S.; Sandakov, V.A.; Zinkle, S.J.; Rowcliffe, A.F.; Edwards, D.J.; Garner, F.A.; Singh, B.N.; Barabash, V.R.

    1996-01-01

    The electrical resistivity and tensile properties of copper and oxide dispersion strengthened (DS) copper alloys have been measured before and after fission neutron irradiation to damage levels of 0.5 to 5 displacements per atom (dps) at ∼100 to 400 degrees C. Some of the specimens were irradiated inside a 1.5 mm Cd shroud in order to reduce the thermal neutron flux. The electrical resistivity data could be separated into two components, a solid transmutation component Δρ tr which was proportional to thermal neutron fluence and a radiation defect component Δρ rd which was independent of the displacement dose. The saturation value for Δρ rd was ∼1.2 nanohm-meters for pure copper and ∼1.6 nanohm-meters for the DS copper alloys irradiated at 100 degrees C in positions with a fast-to-thermal neutron flux ratio of 5. Considerable radiation hardening was observed in all specimens at irradiation temperatures below 200 degrees C. The yield strength was relatively insensitive to neutron spectrum in specimens strengthened by dispersoids or cold- working. 17 refs., 7 figs., 1 tab

  19. The effect of neutron spectrum on the mechanical and physical properties of pure copper and copper alloys

    DEFF Research Database (Denmark)

    Fabritsiev, S.A.; Pokrovsky, A.S.; Zinkle, S.J.

    1996-01-01

    The electrical resistivity and tensile properties of copper and oxide dispersion strengthened (DS) copper alloys have been measured before and after fission neutron irradiation to damage levels of 0.5 to 5 displacements per atom (dpa) at similar to 100 to 400 degrees C. Some of the specimens were......-irradiated inside a 1.5 mm Cd shroud in order to reduce the thermal neutron flux. The electrical resistivity data could be separated into two components, a solid transmutation component Delta rho(tr) which was proportional to thermal neutron fluence and a radiation defect component Delta rho(rd) which...... was independent of displacement dose. The saturation value for Delta rho(rd) was similar to 1.2 n Omega m for pure copper and similar to 1.6 n Omega m for the DS copper alloys irradiated at 100 degrees C in positions with a fast-to-thermal neutron flux ratio of 5, Considerable radiation hardening was observed...

  20. The Role of Grain Size on Neutron Irradiation Response of Nanocrystalline Copper

    Directory of Open Access Journals (Sweden)

    Walid Mohamed

    2016-03-01

    Full Text Available The role of grain size on the developed microstructure and mechanical properties of neutron irradiated nanocrystalline copper was investigated by comparing the radiation response of material to the conventional micrograined counterpart. Nanocrystalline (nc and micrograined (MG copper samples were subjected to a range of neutron exposure levels from 0.0034 to 2 dpa. At all damage levels, the response of MG-copper was governed by radiation hardening manifested by an increase in strength with accompanying ductility loss. Conversely, the response of nc-copper to neutron irradiation exhibited a dependence on the damage level. At low damage levels, grain growth was the primary response, with radiation hardening and embrittlement becoming the dominant responses with increasing damage levels. Annealing experiments revealed that grain growth in nc-copper is composed of both thermally-activated and irradiation-induced components. Tensile tests revealed minimal change in the source hardening component of the yield stress in MG-copper, while the source hardening component was found to decrease with increasing radiation exposure in nc-copper.

  1. Copper complexes as 'radiation recovery' agents

    International Nuclear Information System (INIS)

    Sorenson, J.R.J.

    1989-01-01

    Copper and its compounds have been used for their remedial effects since the beginning of recorded history. As early as 3000 BC the Egyptians used copper as an antiseptic for healing wounds and to sterilise drinking water; and later, ca 1550 BC, the Ebers Papyrus reports the use of copper acetate, copper sulphate and pulverised metallic copper for the treatment of eye infections. These historical uses of copper and its compounds are particularly interesting in the light of modern evidence concerning the use of certain copper complexes for the treatment of radiation sickness and more recently as an adjunct to radiotherapy for cancer patients. (author)

  2. NID Copper Sample Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T.; Zhu, Zihua

    2011-09-12

    The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0νββ). This experiment requires the use of germanium isotopically enriched in 76Ge. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology, possibly one under development at Nonlinear Ion Dynamics (NID), will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL in January 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are reported here. A second sample of isotopically separated copper was provided by NID to PNNL in August 2011 for isotopic analysis as a test of the NID technology. The results of that analysis are also reported here.

  3. Gallium and copper radiopharmaceutical chemistry

    International Nuclear Information System (INIS)

    Green, M.A.

    1991-01-01

    Gallium and copper radionuclides have a long history of use in nuclear medicine. Table 1 presents the nuclear properties of several gallium and copper isotopes that either are used in the routine practice of clinical nuclear medicine or exhibit particular characteristics that might make them useful in diagnostic or therapeutic medicine. This paper will provide some historic perspective along with an overview of some current research directions in gallium and copper radiopharmaceutical chemistry. A more extensive review of gallium radiopharmaceutical chemistry has recently appeared and can be consulted for a more in-depth treatment of this topic

  4. [Effects of copper and zinc cations bound by gamma-globulin fraction in Staphylococcus aureus culture].

    Science.gov (United States)

    Cheknev, S B; Vostrova, E I; Piskovskaia, L S; Vostrov, A V

    2014-01-01

    AIM. Evaluation of Staphylococcus aureus culture growth dynamics in the presence of gamma-globulin: metal-complexes formed with copper and zinc cations as well as cations of metals used in isolation during the first 24 hours of exposition. . Samples of human gamma-globulin metal-complexes with copper or zinc cations at a final concentration of 0.5 microg/ml were introduced into S. aureus bacteria suspensions containing approximately 10(3) CFU/ml. Suspension at the volume of 5.0 ml was incubated at 37 degrees C for 24 hours with sampling and CFU calculation in the culture at various exposure periods. An accepted micromethod for determination of viability of bacteria was used. The protein transformed by copper cation binding realizes bacteriostatic activity in the logarithmic growth phase of S. aureus culture from 3.0 to 6.0 hours of incubation. Free copper cations inhibit bacterial reproduction at a higher degree than the metal-complex. The protein transformed by zinc cation binding realizes bacteriostatic activity at 1.5 hours of S. aureus incubation. Free zinc cations do not have bacteriostatic effect against S. aureus. Proteins of the gamma-globulin fraction in the range of physiological concentrations forming metal-complexes with copper and zinc cations may be factors that have cytostatic effect against S. aureus bacteria. Zinc cations realize bacteriostatic activity only in gamma-gloulin bound state whereas copper cations--also in the free state.

  5. Lactoferrin binding molecules in human seminal plasma.

    Science.gov (United States)

    Thaler, C J; Vanderpuye, O A; McIntyre, J A; Faulk, W P

    1990-10-01

    During ejaculation, the iron binding protein lactoferrin binds to sperm and forms a major component of sperm-coating antigens. Physicochemical properties of lactoferrin in seminal plasma (SP) and on sperm differ from those of purified lactoferrin. These differences have been attributed to the binding of unknown seminal macromolecules to lactoferrin. We have studied lactoferrin binding molecules in SP. The SP samples were coated onto microtiter plates and tested for binding of biotinylated lactoferrin. SP was found to specifically bind biotinylated lactoferrin. This binding was competitively inhibited by coincubation with unlabeled lactoferrin but was not affected by control incubations done with human IgG or transferrin. Lactoferrin binding molecules in SP were biochemically characterized by using SDS-PAGE and ligand blotting. Biotinylated lactoferrin bound to SP molecules of approximately 120, 60 and 30 kDa. No binding was observed with biotinylated transferrin. The presence of molecules that associate with lactoferrin in SP was further studied by using crossed immunoelectrophoresis. Lactoferrin in SP immunoprecipitated as two peaks, one of which corresponded to purified lactoferrin. These results suggest that some lactoferrin molecules in SP are free and that others are associated with lactoferrin binding molecules. Binding of lactoferrin to lactoferrin binding molecules appears to change its physicochemical properties and thus could influence its biologic activity and its affinity to sperm.

  6. Copper transporters and the cellular pharmacology of the platinum-containing cancer drugs.

    Science.gov (United States)

    Howell, Stephen B; Safaei, Roohangiz; Larson, Christopher A; Sailor, Michael J

    2010-06-01

    Multiple lines of evidence indicate that the platinum-containing cancer drugs enter cells, are distributed to various subcellular compartments, and are exported from cells via transporters that evolved to manage copper homeostasis. The cytotoxicity of the platinum drugs is directly related to how much drug enters the cell, and almost all cells that have acquired resistance to the platinum drugs exhibit reduced drug accumulation. The major copper influx transporter, copper transporter 1 (CTR1), has now been shown to control the tumor cell accumulation and cytotoxic effect of cisplatin, carboplatin, and oxaliplatin. There is a good correlation between change in CTR1 expression and acquired cisplatin resistance among ovarian cancer cell lines, and genetic knockout of CTR1 renders cells resistant to cisplatin in vivo. The expression of CTR1 is regulated at the transcriptional level by copper via Sp1 and at the post-translational level by the proteosome. Copper and cisplatin both trigger the down-regulation of CTR1 via a process that involves ubiquitination and proteosomal degradation and requires the copper chaperone antioxidant protein 1 (ATOX1). The cisplatin-induced degradation of CTR1 can be blocked with the proteosome inhibitor bortezomib, and this increases the cellular uptake and the cytotoxicity of cisplatin in a synergistic manner. Copper and platinum(II) have similar sulfur binding characteristics, and the presence of stacked rings of methionines and cysteines in the CTR1 trimer suggest a mechanism by which CTR1 selectively transports copper and the platinum-containing drugs via sequential transchelation reactions similar to the manner in which copper is passed from ATOX1 to the copper efflux transporters.

  7. [Solubility of metal components into tissue culture medium from dental amalgams (author's transl)].

    Science.gov (United States)

    Kawahara, H; Yamada, T; Nakamura, M; Tomoda, T; Kobayashi, H; Saijo, A; Kawata, Y; Hikari, S

    1981-10-01

    Solubility of metal components into tissue culture medium, YLH, from various dental amalgams including high copper, conventional and copper amalgam was measured with atomic absorption spectrometry. The results obtained were as follows.: 1. Mercury solubility was found much in all the dental amalgams after one day extraction. This was followed by gradual increase in solubility in the high copper amalgams until after seven days. On the otherhand, initial high solubility was maintained in conventional and copper amalgams through the whole experimental period. 2. Higher solubility of silver and copper was recorded in the high copper amalgams. 3. Zinc was only found in Dispersalloy and copper amalgam. 4. Tin was unable to be measured in all the amalgams examined. It was considered that the present results could shed a light on the mechanism for cytotoxicity yielding of the dental amalgams.

  8. Multi-Copper Oxidases and Human Iron Metabolism

    Science.gov (United States)

    Vashchenko, Ganna; MacGillivray, Ross T. A.

    2013-01-01

    Multi-copper oxidases (MCOs) are a small group of enzymes that oxidize their substrate with the concomitant reduction of dioxygen to two water molecules. Generally, multi-copper oxidases are promiscuous with regards to their reducing substrates and are capable of performing various functions in different species. To date, three multi-copper oxidases have been detected in humans—ceruloplasmin, hephaestin and zyklopen. Each of these enzymes has a high specificity towards iron with the resulting ferroxidase activity being associated with ferroportin, the only known iron exporter protein in humans. Ferroportin exports iron as Fe2+, but transferrin, the major iron transporter protein of blood, can bind only Fe3+ effectively. Iron oxidation in enterocytes is mediated mainly by hephaestin thus allowing dietary iron to enter the bloodstream. Zyklopen is involved in iron efflux from placental trophoblasts during iron transfer from mother to fetus. Release of iron from the liver relies on ferroportin and the ferroxidase activity of ceruloplasmin which is found in blood in a soluble form. Ceruloplasmin, hephaestin and zyklopen show distinctive expression patterns and have unique mechanisms for regulating their expression. These features of human multi-copper ferroxidases can serve as a basis for the precise control of iron efflux in different tissues. In this manuscript, we review the biochemical and biological properties of the three human MCOs and discuss their potential roles in human iron homeostasis. PMID:23807651

  9. Non-destructive micro-analytical differentiation of copper pigments in paint layers of works of art using laboratory-based techniques.

    Science.gov (United States)

    Svarcová, Silvie; Cermáková, Zdeňka; Hradilová, Janka; Bezdička, Petr; Hradil, David

    2014-11-11

    An unambiguous identification of pigments in paint layers of works of art forms a substantial part of the description of a painting technique, which is essential for the evaluation of the work of art including determination of the period and/or region of its creation as well as its attribution to a workshop or an author. Copper pigments represent a significant group of materials used in historic paintings. Because of their substantial diversity and, on the other hand, similarity, their identification and differentiation is a challenging task. An analytical procedure for unambiguous determination of both mineral-type (azurite, malachite, posnjakite, atacamite, etc.) and verdigris-type (copper acetates) copper pigments in the paint layers is presented, including light microscopy under VIS and UV light, electron microscopy with elemental microanalysis, Fourier transformed infrared micro-spectroscopy (micro-FTIR), and X-ray powder micro-diffraction (micro-XRD). Micro-Raman measurements were largely hindered by fluorescence. The choice of the analytical methods meets the contemporary requirement of a detailed description of various components in heterogeneous and minute samples of paint layers without their destruction. It is beneficial to use the combination of phase sensitive methods such as micro-FTIR and micro-XRD, because it allows the identification of both mineral-type and verdigris-type copper pigments in one paint layer. In addition, preliminary results concerning the study of the loss of crystallinity of verdigris-type pigments in proteinaceous binding media and the effect of lead white and lead tin yellow as highly absorbing matrix on verdigris identification in paint layers are reported. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Copper tailings in stucco mortars

    Directory of Open Access Journals (Sweden)

    Osvaldo Pavez

    Full Text Available Abstract This investigation addressed the evaluation of the use of copper tailings in the construction industry in order to reduce the impact on the environment. The evaluation was performed by a technical comparison between stucco mortars prepared with crushed conventional sand and with copper tailings sand. The best results were achieved with the stucco mortars containing tailings. The tailings presented a fine particles size distribution curve different from that suggested by the standard. The values of compressive strength, retentivity, and adherence in the stucco mortars prepared with copper tailings were much higher than those obtained with crushed sand. According to the results from this study, it can be concluded that the preparation of stucco mortars using copper tailings replacing conventional sand is a technically feasible alternative for the construction industry, presenting the benefit of mitigating the impact of disposal to the environment.

  11. Hereditary iron and copper deposition

    DEFF Research Database (Denmark)

    Aaseth, Jan; Flaten, Trond Peder; Andersen, Ole

    2007-01-01

    Hereditary deposition of iron (primary haemochromatosis) or copper (Wilson's disease) are autosomal recessive metabolic disease characterized by progressive liver pathology and subsequent involvement of various other organs. The prevalence of primary haemochromatosis is approximately 0.5%, about...

  12. Distribution and chemical forms of copper in the root cells of castor seedlings and their tolerance to copper phytotoxicity in hydroponic culture.

    Science.gov (United States)

    Kang, Wei; Bao, Jianguo; Zheng, Jin; Hu, Hongqin; Du, Jiangkun

    2015-05-01

    The subcellular localization and chemical forms of copper in castor (Ricinus communis L.) seedlings grown in hydroponic nutrient solution were identified by chemical extraction, transmission electron microscopy, and Fourier transform infrared spectroscopy. The wild castor seeds were harvested from an abandoned copper mine in Tonglu Mountain, Daye City of Hubei Province, China. The results revealed that (1) the seedlings grew naturally in MS liquid medium with 40.00 mg kg(-1) CuSO4, in which the seedling growth rate and biomass index were 0.14 and 1.23, respectively, which were the highest values among all the treatments. The copper content in castor seedlings increased along with elevated CuSO4 concentration in the medium, reaching a maximum value of 16 570.12 mg kg(-1)(DW) when exposed to 60.00 mg L(-1) CuSO4, where 91.31% of the copper was accumulated in roots. (2) The copper existed in various chemical forms in the roots of the castor seedlings. Copper of 67.66% was extracted from the components of cell walls, such as exchangeable acidic polar compounds, cellulose and lignin, protein and pectin, and less concentrated in cell cytoplasm and nuclei. (3) Furthermore, the root cell walls were thickened when the castor seedlings exposed to CuSO4, with a large amount of high-density electron bodies, attached to the thickened cell walls. In the cell walls, most copper was bound to the carboxyl (-COOH) and hydroxyl (-OH) groups of acidic polar compounds, cellulose, hemicellulose, and polysaccharides. The conclusion showed that castor exhibited a strong tolerance to copper, the copper were accumulated mainly in the root cell, the root cell walls of castor were the major location of patience and detoxification in copper stress.

  13. Crystal structure of a copper-transporting PIB-type ATPase

    DEFF Research Database (Denmark)

    Gourdon, Pontus Emanuel; Liu, Xiang-Yu; Skjørringe, Tina

    2011-01-01

    Heavy-metal homeostasis and detoxification is crucial for cell viability. P-type ATPases of the class IB (PIB) are essential in these processes, actively extruding heavy metals from the cytoplasm of cells. Here we present the structure of a PIB-ATPase, a Legionella pneumophila CopA Cu......(+)-ATPase, in a copper-free form, as determined by X-ray crystallography at 3.2 Å resolution. The structure indicates a three-stage copper transport pathway involving several conserved residues. A PIB-specific transmembrane helix kinks at a double-glycine motif displaying an amphipathic helix that lines a putative...... copper entry point at the intracellular interface. Comparisons to Ca(2+)-ATPase suggest an ATPase-coupled copper release mechanism from the binding sites in the membrane via an extracellular exit site. The structure also provides a framework to analyse missense mutations in the human ATP7A and ATP7B...

  14. Copper atomic-scale transistors

    Directory of Open Access Journals (Sweden)

    Fangqing Xie

    2017-03-01

    Full Text Available We investigated copper as a working material for metallic atomic-scale transistors and confirmed that copper atomic-scale transistors can be fabricated and operated electrochemically in a copper electrolyte (CuSO4 + H2SO4 in bi-distilled water under ambient conditions with three microelectrodes (source, drain and gate. The electrochemical switching-on potential of the atomic-scale transistor is below 350 mV, and the switching-off potential is between 0 and −170 mV. The switching-on current is above 1 μA, which is compatible with semiconductor transistor devices. Both sign and amplitude of the voltage applied across the source and drain electrodes (Ubias influence the switching rate of the transistor and the copper deposition on the electrodes, and correspondingly shift the electrochemical operation potential. The copper atomic-scale transistors can be switched using a function generator without a computer-controlled feedback switching mechanism. The copper atomic-scale transistors, with only one or two atoms at the narrowest constriction, were realized to switch between 0 and 1G0 (G0 = 2e2/h; with e being the electron charge, and h being Planck’s constant or 2G0 by the function generator. The switching rate can reach up to 10 Hz. The copper atomic-scale transistor demonstrates volatile/non-volatile dual functionalities. Such an optimal merging of the logic with memory may open a perspective for processor-in-memory and logic-in-memory architectures, using copper as an alternative working material besides silver for fully metallic atomic-scale transistors.

  15. The copper deposits of Michigan

    Science.gov (United States)

    Butler, B.S.; Burbank, W.S.

    1929-01-01

    The copper district of Keweenaw Point, in the northern peninsula of Michigan, is the second largest producer of copper in the world.  The output of the district since 1845 has been more than 7,500,000,000 pounds and showed a rather steady and consistent increase from the beginning of production to the end of the World War in 1918, since which there has been a marked decrease.

  16. Atmospheric corrosion effects on copper

    International Nuclear Information System (INIS)

    Franey, J.P.

    1985-01-01

    Studies have been performed on the naturally formed patina on various copper samples. Samples have been obtained from structures at AT and T Bell Laboratories, Murray Hill, NJ (40,2,1 and <1 yr) and the Statue of Liberty (100 yr). The samples show a distinct layering effect, that is, the copper base material shows separate oxide and basic sulfate layers on all samples, indicating that patina is not a homogeneous mixture of oxides and basic sulfates

  17. Fusaric acid induces a notochord malformation in zebrafish via copper chelation.

    Science.gov (United States)

    Yin, Emily S; Rakhmankulova, Malika; Kucera, Kaury; de Sena Filho, Jose Guedes; Portero, Carolina E; Narváez-Trujillo, Alexandra; Holley, Scott A; Strobel, Scott A

    2015-08-01

    Over a thousand extracts were tested for phenotypic effects in developing zebrafish embryos to identify bioactive molecules produced by endophytic fungi. One extract isolated from Fusarium sp., a widely distributed fungal genus found in soil and often associated with plants, induced an undulated notochord in developing zebrafish embryos. The active compound was isolated and identified as fusaric acid. Previous literature has shown this phenotype to be associated with copper chelation from the active site of lysyl oxidase, but the ability of fusaric acid to bind copper ions has not been well described. Isothermal titration calorimetry revealed that fusaric acid is a modest copper chelator with a binding constant of 4.4 × 10(5) M(-1). These results shed light on the toxicity of fusaric acid and the potential teratogenic effects of consuming plants infected with Fusarium sp.

  18. Sorption of copper(II) from aqueous phase by waste biomass

    Energy Technology Data Exchange (ETDEWEB)

    Nagendra Rao, C.R. (Government Polytechnic, Anantapur (India)); Iyengar, L.; Venkobachar, C. (Indian Inst. of Tech., Kanpur (India))

    The objective of the present investigation is to compare three biomasses for copper uptake under different experimental conditions so as to choose the most suitable one for scaleup purposes. Ganoderma lucidum is a macrofungi, growing widely in tropical forests. Sorbent preparation requires its collection from the field. Asperigillus niger is obtained as a waste biomass from the fermentation industry. Activated sludge biomass is available from the biological waste treatment plants. The results of their potential to remove copper are presented. The copper uptake by biosorbents though, varied significantly, showed an increased trend in the range of pH 4 to 6. The increase in metal binding after alkali treatment was marginal for G. lucidum, significant for A. niger, and dramatic for sludge. Copper sorption capacities of M and M[sub c] were much higher than for other sorbents at pH 5.0. The effect of anionic ligands, like acetate and tartrate on copper uptake by raw and alkali treated biosorbents, was negligible as the predominant species in the presence of these ligands is divalent copper ion. Pyrophosphate, citrate, and EDTA had varying degrees of adverse effects on metal uptake. Thus, among the sorbents G. lucidum in its raw form is best suited for the practical application of copper removal from industrial effluents.

  19. Fluorescence-based determination of the copper concentration in drinking water

    Science.gov (United States)

    Hötzer, Benjamin; Scheu, Timo; Jung, Gregor; Castritius, Stefan

    2013-05-01

    Copper is a heavy metal, which is used in heat and electrical conductors and in a multitude of alloys in the technical context. Moreover, it is a trace element that is essential for the life of organisms but can cause toxic effects in elevated concentrations. Maximum limits in water and beverages exist. Here, the decrease of the fluorescence lifetime of green fluorescent protein (GFP) by Förster resonance energy transfer is used to measure the copper ion concentration in drinking water. Therefore, a system is developed that is based on a GFP sample in a predefined concentration. The GFP mutant can be excited with blue light. For binding of copper ions, a His-tag is included in the GFP. After measuring the fluorescence lifetime of pure GFP, the copper determination of the sample is performed by lifetime measurement. Therefore, the lifetime can be assigned to the copper concentration of the GFP-doped drinking water sample. In summary, a method for the quantification of copper ions based on changes of the fluorescence lifetime of GFP is developed, and the measurement of the copper concentration in water samples is performed.

  20. Genome Sequences of Two Copper-Resistant Escherichia coli Strains Isolated from Copper-Fed Pigs

    DEFF Research Database (Denmark)

    Lüthje, Freja L.; Hasman, Henrik; Aarestrup, Frank Møller

    2014-01-01

    The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances.......The draft genome sequences of two copper-resistant Escherichia coli strains were determined. These had been isolated from copper-fed pigs and contained additional putative operons conferring copper and other metal and metalloid resistances....

  1. Utilization of Polyethylene Waste and Polypropylene Wastes for Formation of Fine Copper Ore Concentrates

    Science.gov (United States)

    Szyszka, Danuta; Więckowska, Jadwiga

    2016-10-01

    The possibilities for utilization of polyethylene waste and polypropylene waste as a binding material for formation of fine grain of copper ore concentrate in Hake Rheomix were examined. The optimum parameters of the formation processes were established. Strength, thermal and microscopic properties the products obtained were determined.

  2. Synthesis, molecular structures and ESI-mass studies of copper(I ...

    Indian Academy of Sciences (India)

    PPh3)2Cu(µ-N,S-SCN)2. Cu(PPh3)2] 4 in each case (figure 4). Here, in these reactions also, the thio-ligands pySH (or pymSH) gave red precipitate with copper(I) thiocyanate suggesting binding to metal center, but the addition of PPh3 de-.

  3. Yeast CUP1 protects HeLa cells against copper-induced stress

    Energy Technology Data Exchange (ETDEWEB)

    Xie, X.X. [Department of Animal Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai (China); Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai (China); College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou (China); Ma, Y.F.; Wang, Q.S.; Chen, Z.L.; Liao, R.R.; Pan, Y.C. [Department of Animal Sciences, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai (China); Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai (China)

    2015-06-12

    As an essential trace element, copper can be toxic in mammalian cells when present in excess. Metallothioneins (MTs) are small, cysteine-rich proteins that avidly bind copper and thus play an important role in detoxification. YeastCUP1 is a member of the MT gene family. The aim of this study was to determine whether yeast CUP1 could bind copper effectively and protect cells against copper stress. In this study,CUP1 expression was determined by quantitative real-time PCR, and copper content was detected by inductively coupled plasma mass spectrometry. Production of intracellular reactive oxygen species (ROS) was evaluated using the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay. Cellular viability was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the cell cycle distribution of CUP1 was analyzed by fluorescence-activated cell sorting. The data indicated that overexpression of yeast CUP1 in HeLa cells played a protective role against copper-induced stress, leading to increased cellular viability (P<0.05) and decreased ROS production (P<0.05). It was also observed that overexpression of yeast CUP1 reduced the percentage of G1 cells and increased the percentage of S cells, which suggested that it contributed to cell viability. We found that overexpression of yeast CUP1 protected HeLa cells against copper stress. These results offer useful data to elucidate the mechanism of the MT gene on copper metabolism in mammalian cells.

  4. Spectroscopic characterization of a green copper site in a single-domain cupredoxin.

    Science.gov (United States)

    Roger, Magali; Biaso, Frédéric; Castelle, Cindy J; Bauzan, Marielle; Chaspoul, Florence; Lojou, Elisabeth; Sciara, Giuliano; Caffarri, Stefano; Giudici-Orticoni, Marie-Thérèse; Ilbert, Marianne

    2014-01-01

    Cupredoxins are widespread copper-binding proteins, mainly involved in electron transfer pathways. They display a typical rigid greek key motif consisting of an eight stranded β-sandwich. A fascinating feature of cupredoxins is the natural diversity of their copper center geometry. These geometry variations give rise to drastic changes in their color, such as blue, green, red or purple. Based on several spectroscopic and structural analyses, a connection between the geometry of their copper-binding site and their color has been proposed. However, little is known about the relationship between such diversity of copper center geometry in cupredoxins and possible implications for function. This has been difficult to assess, as only a few naturally occurring green and red copper sites have been described so far. We report herein the spectrocopic characterization of a novel kind of single domain cupredoxin of green color, involved in a respiratory pathway of the acidophilic organism Acidithiobacillus ferrooxidans. Biochemical and spectroscopic characterization coupled to bioinformatics analysis reveal the existence of some unusual features for this novel member of the green cupredoxin sub-family. This protein has the highest redox potential reported to date for a green-type cupredoxin. It has a constrained green copper site insensitive to pH or temperature variations. It is a green-type cupredoxin found for the first time in a respiratory pathway. These unique properties might be explained by a region of unknown function never found in other cupredoxins, and by an unusual length of the loop between the second and the fourth copper ligands. These discoveries will impact our knowledge on non-engineered green copper sites, whose involvement in respiratory chains seems more widespread than initially thought.

  5. Spectroscopic characterization of a green copper site in a single-domain cupredoxin.

    Directory of Open Access Journals (Sweden)

    Magali Roger

    Full Text Available Cupredoxins are widespread copper-binding proteins, mainly involved in electron transfer pathways. They display a typical rigid greek key motif consisting of an eight stranded β-sandwich. A fascinating feature of cupredoxins is the natural diversity of their copper center geometry. These geometry variations give rise to drastic changes in their color, such as blue, green, red or purple. Based on several spectroscopic and structural analyses, a connection between the geometry of their copper-binding site and their color has been proposed. However, little is known about the relationship between such diversity of copper center geometry in cupredoxins and possible implications for function. This has been difficult to assess, as only a few naturally occurring green and red copper sites have been described so far. We report herein the spectrocopic characterization of a novel kind of single domain cupredoxin of green color, involved in a respiratory pathway of the acidophilic organism Acidithiobacillus ferrooxidans. Biochemical and spectroscopic characterization coupled to bioinformatics analysis reveal the existence of some unusual features for this novel member of the green cupredoxin sub-family. This protein has the highest redox potential reported to date for a green-type cupredoxin. It has a constrained green copper site insensitive to pH or temperature variations. It is a green-type cupredoxin found for the first time in a respiratory pathway. These unique properties might be explained by a region of unknown function never found in other cupredoxins, and by an unusual length of the loop between the second and the fourth copper ligands. These discoveries will impact our knowledge on non-engineered green copper sites, whose involvement in respiratory chains seems more widespread than initially thought.

  6. Serous carcinomatous component championed by heparin-binding EGF-like growth factor (HB-EGF) predisposing to metastasis and recurrence in stage I uterine malignant mixed mullerian tumor.

    Science.gov (United States)

    Zhang, Lei; Shimizu, David; Killeen, Jeffrey L; Honda, Stacey A; Lu, Di; Stanoyevitch, Alexander; Lin, Fritz; Wang, Beverly; Monuki, Edwin S; Carbone, Michele

    2016-07-01

    The stage I uterine malignant mixed mullerian tumor (MMMT) shows different potential for progression. We reason that MMMTs with high-grade carcinomatous component and positivity for HB-EGF are prone to recurrence/metastasis in the early stage. A retrospective clinical and histopathologic review with immunohistochemical staining for HB-EGF, EGFR, and integrin-α5 was performed for 62 surgically staged MMMT cases. Recurrence/metastasis (RM) is 6/18 (33%) in stage I disease. Of all the clinicopathologic variables and biomarkers analyzed for stage I MMMT, serous carcinomatous component (83% [5/6] versus 17% [1/12], P = .0015) and HB-EGF expression (100% [6/6] versus 50% [6/12], P=.0339) were significantly different between groups with RM and without RM. The presence of serous carcinoma in all stages was 83% (5/6) in stage I with RM, 8% (1/12) in stage I without RM, 20% (1/5) in stage II, 36.4% (8/22) in stage III and 64.7% (11/17) in stage IV; this was paralleled by HB-EGF expression of 100% (6/6), 50% (6/12), 40% (2/5), 50% (11/22) and 71% (12/17) with a correlation coefficient r=0.9131 (P=.027). HB-EGF and integrin-α5 were highly expressed in MMMTs bearing serous carcinoma component, compared to endometrioid and unclassifiable/miscellaneous subtypes (84.6%/47.6%/33.3%, P=.025 for HB-EGF; and 61.5%/42.9%/20.0%, P=.021 for integrin-α5). The EGFR positivity was comparable among the three subtypes (48.1%, 47.6% and 26.7%, P=.326). This study indicates that serous carcinomatous component championed by expression of HB-EGF predisposes to recurrence/metastasis in stage I MMMT. This process might involve integrin-α5 and does not seem to require overexpression of EGFR. Further study is required. Published by Elsevier Inc.

  7. Magnetic Interactions in the Copper Complex (L-Aspartato)(1,10-phenanthroline)copper(II) Hydrate. An Exchange-Coupled Extended System with Two Dissimilar Copper Ions.

    Science.gov (United States)

    Brondino, Carlos D.; Calvo, Rafael; Atria, Ana María; Spodine, Evgenia; Nascimento, Otaciro R.; Peña, Octavio

    1997-07-02

    We report EPR measurements in single-crystal samples at the microwave frequencies 9.8 and 34.3 GHz and magnetic susceptibility measurements in polycrystalline samples for the ternary complex of copper with aspartic acid and phenanthroline, (L-aspartato)(1,10-phenanthroline)copper(II) hydrate. The crystal lattice of this compound is composed of two dissimilar copper ions identified as Cu(A) and Cu(B), which are in two types of copper chains called A and B, respectively, running parallel to the b crystal axis. The copper ions in the A chains are connected by the aspartic acid molecule, and those in the B chains by a chemical path that involves a carboxylate bridge and a hydrogen bond. Both chains are held together by a complex network of hydrogen bonds and by hydrophobic interactions between aromatic amines. Magnetic susceptibility data indicate a Curie-Weiss behavior in the studied temperature range (2-300 K). The EPR spectra at 9.8 GHz display a single exchange collapsed resonance for any magnetic field orientation, in the so-called strong exchange regime. Those at 34.3 GHz are within the so-called weak exchange regime and display two resonances which belong to each type of copper ion chain. The decoupling of the spectra at 34.3 GHz using a theory based on Anderson's model for the case of two weakly exchange coupled spins S = (1)/(2) allows one to obtain the angular variation of the squares of the g-factor and the peak-to-peak line width of each resonance. This model also allows one to evaluate the exchange parameter |J(AB)/k| = 2.7(6) mK associated with the chemical path connecting dissimilar copper ions. The line width data obtained for each component of the spectra at 34.3 GHz are analyzed in terms of a model based on Kubo and Tomita's theory, to obtain the exchange parameters |J(A)/k| = 0.77(2) K and |J(B)/k| = 1.44(2) K associated with the chemical paths connecting the similar copper ions of types A and B, respectively.

  8. Copper slag as a catalyst for mercury oxidation in coal combustion flue gas.

    Science.gov (United States)

    Li, Hailong; Zhang, Weilin; Wang, Jun; Yang, Zequn; Li, Liqing; Shih, Kaimin

    2018-04-01

    Copper slag is a byproduct of the pyrometallurgical smelting of copper concentrate. It was used in this study to catalyze elemental mercury (Hg 0 ) oxidation in simulated coal combustion flue gas. The copper slag exhibited excellent catalytic performance in Hg 0 oxidation at temperatures between 200 °C and 300 °C. At the most optimal temperature of 250 °C, a Hg 0 oxidation efficiency of 93.8% was achieved under simulated coal combustion flue gas with both a high Hg 0 concentration and a high gas hourly space velocity of 128,000 h -1 . Hydrogen chloride (HCl) was the flue gas component responsible for Hg 0 oxidation over the copper slag. The transition metal oxides, including iron oxides and copper oxide in the copper slag, exhibited significant catalytic activities in the surface-mediated oxidation of Hg 0 in the presence of HCl. It is proposed that the Hg 0 oxidation over the copper slag followed the Langmuir-Hinshelwood mechanism whereby reactive chlorine species that originated from HCl reacted with the physically adsorbed Hg 0 to form oxidized mercury. This study demonstrated the possibility of reusing copper slag as a catalyst for Hg 0 oxidation and revealed the mechanisms involved in the process and the key factors in the performance. This knowledge has fundamental importance in simultaneously reducing industrial waste and controlling mercury emissions from coal-fired power plants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. NID Copper Sample Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kouzes, Richard T.; Zhu, Zihua

    2011-02-01

    The current focal point of the nuclear physics program at PNNL is the MAJORANA DEMONSTRATOR, and the follow-on Tonne-Scale experiment, a large array of ultra-low background high-purity germanium detectors, enriched in 76Ge, designed to search for zero-neutrino double-beta decay (0νββ). This experiment requires the use of germanium isotopically enriched in 76Ge. The DEMONSTRATOR will utilize 76Ge from Russia, but for the Tonne-Scale experiment it is hoped that an alternate technology under development at Nonlinear Ion Dynamics (NID) will be a viable, US-based, lower-cost source of separated material. Samples of separated material from NID require analysis to determine the isotopic distribution and impurities. The MAJORANA DEMONSTRATOR is a DOE and NSF funded project with a major science impact. DOE is funding NID through an SBIR grant for development of their separation technology for application to the Tonne-Scale experiment. The Environmental Molecular Sciences facility (EMSL), a DOE user facility at PNNL, has the required mass spectroscopy instruments for making these isotopic measurements that are essential to the quality assurance for the MAJORANA DEMONSTRATOR and for the development of the future separation technology required for the Tonne-Scale experiment. A sample of isotopically separated copper was provided by NID to PNNL for isotopic analysis as a test of the NID technology. The results of that analysis are reported here.

  10. Renal cortex copper concentration in acute copper poisoning in calves

    Directory of Open Access Journals (Sweden)

    Luis E. Fazzio

    2012-01-01

    Full Text Available The aim of this study was to estimate the diagnostic value of renal cortex copper (Cu concentration in clinical cases of acute copper poisoning (ACP. A total of 97 calves that died due to subcutaneous copper administration were compiled in eleven farms. At least, one necropsy was conducted on each farm and samples for complementary analysis were taken. The degree of autolysis in each necropsy was evaluated. The cases appeared on extensive grazing calf breeding and intensive feedlot farms, in calves of 60 to 200 kg body weight. Mortality varied from 0.86 to 6.96 %, on the farms studied. The first succumbed calf was found on the farms between 6 and 72 hours after the susbcutaneous Cu administration. As discrepancies regarding the reference value arose, the local value (19.9 parts per million was used, confirming the diagnosis of acute copper poisoning in 93% of the analyzed kidney samples. These results confirm the value of analysis of the cortical kidney Cu concentration for the diagnosis of acute copper poisoning.

  11. Copper metallurgy at the crossroads

    Directory of Open Access Journals (Sweden)

    Habashi F.

    2007-01-01

    Full Text Available Copper technology changed from the vertical to the horizontal furnace and from the roast reaction to converting towards the end of the last century. However, the horizontal furnace proved to be an inefficient and polluting reactor. As a result many attempts were made to replace it. In the past 50 years new successful melting processes were introduced on an industrial scale that were more energy efficient and less polluting. In addition, smelting and converting were conducted in a single reactor in which the concentrate was fed and the raw copper was produced. The standing problem in many countries, however, is marketing 3 tonnes of sulfuric acid per tonne of copper produced as well as emitting large amounts of excess SO2 in the atmosphere. Pressure hydrometallurgy offers the possibility of liberating the copper industry from SO2 problem. Heap leaching technology has become a gigantic operation. Combined with solvent extraction and electrowinning it contributes today to about 20% of copper production and is expected to grow. Pressure leaching offers the possibility of liberating the copper industry from SO2 problem. The technology is over hundred years old. It is applied for leaching a variety of ores and concentrates. Hydrothermal oxidation of sulfide concentrates has the enormous advantage of producing elemental sulfur, hence solving the SO2 and sulfuric acid problems found in smelters. Precipitation of metals such as nickel and cobalt under hydrothermal conditions has been used for over 50 years. It has the advantage of a compact plant but the disadvantage of producing ammonium sulfate as a co-product. In case of copper, however, precipitation takes place without the need of neutralizing the acid, which is a great advantage and could be an excellent substitute for electrowinning which is energy intensive and occupies extensive space. Recent advances in the engineering aspects of pressure equipment design open the door widely for increased

  12. Silane pre-treatments on copper and aluminium

    International Nuclear Information System (INIS)

    Deflorian, F.; Rossi, S.; Fedrizzi, L.

    2006-01-01

    A large part of aluminium products are coated with an organic layer in order to improve the corrosion resistance. Copper surfaces are also sometimes protected with an organic coating to improve the durability or the aesthetic properties. Examples of industrial applications are household appliances and heat exchanger components. For these applications it is not rare to have the industrial need to treat at the same time components made of aluminium and copper. In order to extend the service life of the organic coated copper a specific surface pre-treatment is often required. Nevertheless, probably because of the limited market of this application, no specific pre-treatments for copper are industrially developed, with the exception of cleaning procedures, but simply extensions of existing pre-treatments optimised for other metals (aluminium, zinc) are used. The application of silane pre-treatments as adhesion promoters for organic coated metals is remarkably increasing in the last decade, because silanes offer very good performance together with high environmental compatibility. The idea is therefore to try to develop a specific silane based pre-treatment for copper. The starting point is the existing silane products for aluminium, optimising the composition and the application conditions (concentration, temperature, pH of the bath, etc.) in order to develop a high performance copper alloy pre-treatment increasing the protective properties and the adhesion of a successively applied organic coating. Moreover these pre-treatments could be used for aluminium alloys too and therefore could be suggested for multi-metals components. The deposits were analysed using FTIR spectroscopy and optical and electron microscopic observations. A careful electrochemical characterisation, mainly by electrochemical impedance spectroscopy measurements (EIS) was carried out to highlight the presence of silane and to evaluate the performance of the different deposits. In order to study an

  13. Crystal Structures of Copper-depleted and Copper-bound Fungal Pro-tyrosinase

    Science.gov (United States)

    Fujieda, Nobutaka; Yabuta, Shintaro; Ikeda, Takuya; Oyama, Takuji; Muraki, Norifumi; Kurisu, Genji; Itoh, Shinobu

    2013-01-01

    Tyrosinase, a dinuclear copper monooxygenase/oxidase, plays a crucial role in the melanin pigment biosynthesis. The structure and functions of tyrosinase have so far been studied extensively, but the post-translational maturation process from the pro-form to the active form has been less explored. In this study, we provide the crystal structures of Aspergillus oryzae full-length pro-tyrosinase in the holo- and the apo-forms at 1.39 and 2.05 Å resolution, respectively, revealing that Phe513 on the C-terminal domain is accommodated in the substrate-binding site as a substrate analog to protect the dicopper active site from substrate access (proteolytic cleavage of the C-terminal domain or deformation of the C-terminal domain by acid treatment transforms the pro-tyrosinase to the active enzyme (Fujieda, N., Murata, M., Yabuta, S., Ikeda, T., Shimokawa, C., Nakamura, Y., Hata, Y., and Itoh, S. (2012) ChemBioChem. 13, 193–201 and Fujieda, N., Murata, M., Yabuta, S., Ikeda, T., Shimokawa, C., Nakamura, Y., Hata, Yl, and Itoh, S. (2013) J. Biol. Inorg. Chem. 18, 19–26). Detailed crystallographic analysis and structure-based mutational studies have shown that the copper incorporation into the active site is governed by three cysteines as follows: Cys92, which is covalently bound to His94 via an unusual thioether linkage in the holo-form, and Cys522 and Cys525 of the CXXC motif located on the C-terminal domain. Molecular mechanisms of the maturation processes of fungal tyrosinase involving the accommodation of the dinuclear copper unit, the post-translational His-Cys thioether cross-linkage formation, and the proteolytic C-terminal cleavage to produce the active tyrosinase have been discussed on the basis of the detailed structural information. PMID:23749993

  14. Production of bio-oil with low contents of copper and chlorine by fast pyrolysis of alkaline copper quaternary-treated wood in a fluidized bed reactor

    International Nuclear Information System (INIS)

    Koo, Won-Mo; Jung, Su-Hwa; Kim, Joo-Sik

    2014-01-01

    Fast pyrolysis of ACQ (alkaline copper quaternary)-treated wood was carried out in a bench-scale pyrolysis plant equipped with a fluidized bed reactor and char separation system. This study focused on the production of a bio-oil with low copper and chlorine contents, especially by adopting the fractional condensation of bio-oil using water condensers, an impact separator and an electrostatic precipitator. In addition, various analytical tools were applied to investigate the physicochemical properties of the pyrolysis products and the behavior of the preservative during pyrolysis. The bio-oil yield was maximized at 63.7 wt% at a pyrolysis temperature of 411 °C. Highly water-soluble holocellulose-derived components such as acetic acid and hydroxyacetone were mainly collected by the condensers, while lignin-derived components and levoglucosan were mainly observed in the oils collected by the impact separator and electrostatic precipitator. All the bio-oils produced in the experiments were almost free of copper and chlorine. Most copper in ACQ was transferred into the char. - Highlights: • ACQ(alkaline copper quaternary)-treated wood was successfully pyrolyzed in a bench-scale fluidized bed. • Bio-oils separately collected were different in their characteristics. • Bio-oils were free of didecyldimethylammonium chloride. • Bio oils were almost free of copper and chlorine. • The concentration of levoglucosan in a bio-oil was 24–31 wt%

  15. Water binding in legume seeds

    Science.gov (United States)

    Vertucci, C. W.; Leopold, A. C.

    1987-01-01

    The physical status of water in seeds has a pivotal role in determining the physiological reactions that can take place in the dry state. Using water sorption isotherms from cotyledon and axis tissue of five leguminous seeds, the strength of water binding and the numbers of binding sites have been estimated using van't Hoff analyses and the D'Arcy/Watt equation. These parameters of water sorption are calculated for each of the three regions of water binding and for a range of temperatures. Water sorption characteristics are reflective of the chemical composition of the biological materials as well as the temperature at which hydration takes place. Changes in the sorption characteristics with temperature and hydration level may suggest hydration-induced structural changes in cellular components.

  16. Component Rhinoplasty

    OpenAIRE

    Mohmand, Muhammad Humayun; Ahmad, Muhammad

    2014-01-01

    BACKGROUND According to statistics of American Society of Plastic Surgeons, cosmetic rhinoplasty was the second most frequently performed cosmetic surgery. This study shares the experiences with component rhinoplasty. METHODS From 2004 to 2010, all patients underwent aesthetic nasal surgery were enrolled. The patients requiring only correction of septal deviation and those presenting with cleft lip nasal deformity were excluded. All procedures were performed under general anaesthesia with ope...

  17. Hyperfrequency components

    Science.gov (United States)

    1994-09-01

    The document has a collection of 19 papers (11 on technologies, 8 on applications) by 26 authors and coauthors. Technological topics include: evolution from conventional HEMT's double heterojunction and planar types of pseudomorphic HEMT's; MMIC R&D and production aspects for very-low-noise, low-power, and very-low-noise, high-power applications; hyperfrequency CAD tools; parametric measurements of hyperfrequency components on plug-in cards for design and in-process testing uses; design of Class B power amplifiers and millimetric-wave, bigrid-transistor mixers, exemplifying combined use of three major types of physical simulation in electrical modeling of microwave components; FET's for power amplification at up to 110 GHz; production, characterization, and nonlinear applications of resonant tunnel diodes. Applications topics include: development of active modules for major European programs; tubes versus solid-state components in hyperfrequency applications; status and potentialities of national and international cooperative R&D on MMIC's and CAD of hyperfrequency circuitry; attainable performance levels in multifunction MMIC applications; state of the art relative of MESFET power amplifiers (Bands S, C, X, Ku); creating a hyperfrequency functions library, of parametrizable reference cells or macrocells; and design of a single-stage, low-noise, band-W amplifier toward development of a three-stage amplifier.

  18. New Aspects of the Interplay between Penicillin Binding Proteins,murM, and the Two-Component System CiaRH of Penicillin-Resistant Streptococcus pneumoniae Serotype 19A Isolates from Hungary.

    Science.gov (United States)

    Schweizer, Inga; Blättner, Sebastian; Maurer, Patrick; Peters, Katharina; Vollmer, Daniela; Vollmer, Waldemar; Hakenbeck, Regine; Denapaite, Dalia

    2017-07-01

    The Streptococcus pneumoniae clone Hungary 19A -6 expresses unusually high levels of β-lactam resistance, which is in part due to mutations in the MurM gene, encoding a transferase involved in the synthesis of branched peptidoglycan. Moreover, it contains the allele ciaH232 , encoding the histidine kinase CiaH (M. Müller, P. Marx, R. Hakenbeck, and R. Brückner, Microbiology 157:3104-3112, 2011, https://doi.org/10.1099/mic.0.053157-0). High-level penicillin resistance primarily requires the presence of low-affinity (mosaic) penicillin binding protein (PBP) genes, as, for example, in strain Hu17, a closely related member of the Hungary 19A -6 lineage. Interestingly, strain Hu15 is β-lactam sensitive due to the absence of mosaic PBPs. This unique situation prompted us to investigate the development of cefotaxime resistance in transformation experiments with genes known to play a role in this phenotype, pbp2x , pbp1a , murM , and ciaH , and penicillin-sensitive recipient strains R6 and Hu15. Characterization of phenotypes, peptidoglycan composition, and CiaR-mediated gene expression revealed several novel aspects of penicillin resistance. The murM gene of strain Hu17 ( murM Hu17 ), which is highly similar to murM of Streptococcus mitis , induced morphological changes which were partly reversed by ciaH232. murM Hu17 conferred cefotaxime resistance only in the presence of the pbp2x o f strain Hu17 ( pbp2x Hu17 ). The ciaH232 allele contributed to a remarkable increase in cefotaxime resistance in combination with pbp2x Hu17 and pbp1a of strain Hu17 ( pbp1a Hu17 ), accompanied by higher levels of expression of CiaR-regulated genes, documenting that ciaH232 responds to PBP1a Hu17 -mediated changes in cell wall synthesis. Most importantly, the proportion of branched peptides relative to the proportion of linear muropeptides increased in cells containing mosaic PBPs, suggesting an altered enzymatic activity of these proteins. Copyright © 2017 Schweizer et al.

  19. Functionally specified protein signatures distinctive for each of the different blue copper proteins

    Directory of Open Access Journals (Sweden)

    Anishetty Sharmila

    2004-09-01

    Full Text Available Abstract Background Proteins having similar functions from different sources can be identified by the occurrence in their sequences, a conserved cluster of amino acids referred to as pattern, motif, signature or fingerprint. The wide usage of protein sequence analysis in par with the growth of databases signifies the importance of using patterns or signatures to retrieve out related sequences. Blue copper proteins are found in the electron transport chain of prokaryotes and eukaryotes. The signatures already existing in the databases like the type 1 copper blue, multiple copper oxidase, cyt b/b6, photosystem 1 psaA&B, psaG&K, and reiske iron sulphur protein are not specified signatures for blue copper proteins as the name itself suggests. Most profile and motif databases strive to classify protein sequences into a broad spectrum of protein families. This work describes the signatures designed based on the copper metal binding motifs in blue copper proteins. The common feature in all blue copper proteins is a trigonal planar arrangement of two nitrogen ligands [each from histidine] and one sulphur containing thiolate ligand [from cysteine], with strong interactions between the copper center and these ligands. Results Sequences that share such conserved motifs are crucial to the structure or function of the protein and this could provide a signature of family membership. The blue copper proteins chosen for the study were plantacyanin, plastocyanin, cucumber basic protein, stellacyanin, dicyanin, umecyanin, uclacyanin, cusacyanin, rusticyanin, sulfocyanin, halocyanin, azurin, pseudoazurin, amicyanin and nitrite reductase which were identified in both eukaryotes and prokaryotes. ClustalW analysis of the protein sequences of each of the blue copper proteins was the basis for designing protein signatures or peptides. The protein signatures and peptides identified in this study were designed involving the active site region involving the amino acids

  20. Chemical Speciation of Copper in a Salt Marsh Estuary and Bioavailability to Thaumarchaeota

    Directory of Open Access Journals (Sweden)

    Hannah Whitby

    2017-06-01

    Full Text Available The concentrations of dissolved copper (Cud, copper-binding ligands, thiourea-type thiols, and humic substances (HSCu were measured in estuarine waters adjacent to Sapelo Island, Georgia, USA, on a monthly basis from April to December 2014. Here we present the seasonal cycle of copper speciation within the estuary and compare it to the development of an annually occurring bloom of Ammonia Oxidizing Archaea (AOA, which require copper for many enzymes. Two types of complexing ligands (L1 and L2 were found to dominate with mean complex stabilities (log KCuL′ of 14.5 and 12.8. Strong complexation resulted in lowering the concentration of free cupric ion (Cu2+ to femtomolar (fM levels throughout the study and to sub-fM levels during the summer months. A Thaumarchaeota bloom during this period suggests that this organism manages to grow at very low Cu2+ concentrations. Correlation of the concentration of the L1 ligand class with a thiourea-type thiol and the L2 ligand class with HSCu provide an interesting dimension to the identity of the ligand classes. Due to the stronger complex stability, 82–99% of the copper was bound to L1. Thiourea-type thiols typically form Cu(I species, which would suggest that up to ~90% copper could be present as Cu(I in this region. In view of the very low concentration of free copper (pCu > 15 at the onset and during the bloom and a reputedly high requirement for copper, it is likely that the Thaumarchaeota are able to access thiol-bound copper directly.

  1. Experimental comparison on heat transfer-enhancing component of metal hydride bed

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Hyun-goo, E-mail: hgkang@nfri.re.kr; Chung, Dong-you; Oh, Yun Hee; Chang, Min Ho; Yun, Sei-Hun

    2016-11-01

    Highlights: • Two small ZrCo metal hydride beds were developed. • Copper foam or fin as heat transfer-enhancing component are experimentally compared. • Copper foam bed is more efficient for uniform and rapid heating of metal hydride. • Copper foam bed is more efficient in removal of reaction heat during absorption. - Abstract: Metal hydride bed will be one of the key components for safe handling of tritium in fusion fuel cycle. In case of normal or emergency shutdown of fuel cycle, metal hydride bed installed in storage and delivery system (SDS) of tritium plant will absorb tritium gas in the system as soon as possible. Supply of hydrogen isotope gas to fueling system of fusion reactor will start from the metal hydride beds. Rapid delivery, rapid recovery including rapid heating and cooling are key issues. For better performance of metal hydride bed, various forms of heat transfer enhancing component or design can be applied. This study aims to help the selection of heat transfer enhancing component. Two small ZrCo beds with copper foam and copper fin were developed and experimented with hydrogen gas. Recovery and delivery performance, heating and cooling performance are compared. Experimental results show metal hydride bed with copper foam has improved performance. Uniform heating of metal hydride during desorption and removal of reaction heat during absorption are more efficient with copper foam bed than copper fin bed.

  2. Variance Components

    CERN Document Server

    Searle, Shayle R; McCulloch, Charles E

    1992-01-01

    WILEY-INTERSCIENCE PAPERBACK SERIES. The Wiley-Interscience Paperback Series consists of selected books that have been made more accessible to consumers in an effort to increase global appeal and general circulation. With these new unabridged softcover volumes, Wiley hopes to extend the lives of these works by making them available to future generations of statisticians, mathematicians, and scientists. ". . .Variance Components is an excellent book. It is organized and well written, and provides many references to a variety of topics. I recommend it to anyone with interest in linear models.".

  3. Binding energy of protonium ions

    Science.gov (United States)

    Assad Abdel-Raouf, Mohamed

    2009-11-01

    The goal of the present work is to calculate the binding energy of the protonium ions bar PPe+ and bar PPe- using Rayleigh- Ritz variational method. It is indicated that an employment of 21 components of the trial wavefunction yields -0.08793 eV as the ground state energy of these ions. Our result agrees quite well with recently obtained results based on elaborate Monte Carlo approximations. It confirms the possible formation of these ions in laboratory.

  4. Biliary copper excretion by hepatocyte lysosomes in the rat. Major excretory pathway in experimental copper overload

    International Nuclear Information System (INIS)

    Gross, J.B. Jr.; Myers, B.M.; Kost, L.J.; Kuntz, S.M.; LaRusso, N.F.

    1989-01-01

    We investigated the hypothesis that lysosomes are the main source of biliary copper in conditions of hepatic copper overload. We used a rat model of oral copper loading and studied the relationship between the biliary output of copper and lysosomal hydrolases. Male Sprague-Dawley rats were given tap water with or without 0.125% copper acetate for up to 36 wk. Copper loading produced a 23-fold increase in the hepatic copper concentration and a 30-65% increase in hepatic lysosomal enzyme activity. Acid phosphatase histochemistry showed that copper-loaded livers contained an increased number of hepatocyte lysosomes; increased copper concentration of these organelles was confirmed directly by both x ray microanalysis and tissue fractionation. The copper-loaded rats showed a 16-fold increase in biliary copper output and a 50-300% increase in biliary lysosomal enzyme output. In the basal state, excretory profiles over time were similar for biliary outputs of lysosomal enzymes and copper in the copper-loaded animals but not in controls. After pharmacologic stimulation of lysosomal exocytosis, biliary outputs of copper and lysosomal hydrolases in the copper-loaded animals remained coupled: injection of colchicine or vinblastine produced an acute rise in the biliary output of both lysosomal enzymes and copper to 150-250% of baseline rates. After these same drugs, control animals showed only the expected increase in lysosomal enzyme output without a corresponding increase in copper output. We conclude that the hepatocyte responds to an increased copper load by sequestering excess copper in an increased number of lysosomes that then empty their contents directly into bile. The results provide direct evidence that exocytosis of lysosomal contents into biliary canaliculi is the major mechanism for biliary copper excretion in hepatic copper overload

  5. Leaching of Copper Ore by Thiobacillus Ferrooxidans.

    Science.gov (United States)

    Lennox, John; Biaha, Thomas

    1991-01-01

    A quantitative laboratory exercise based upon the procedures copper manufacturers employ to increase copper production is described. The role of chemoautotrophic microorganisms in biogeologic process is emphasized. Safety considerations when working with bacteria are included. (KR)

  6. Electrochemical behaviour of alkaline copper complexes

    Indian Academy of Sciences (India)

    cyanide- plating bath for copper has been developed using alkaline trisodium citrate and triethanolamine solutions5. The present investigation presents cyclic voltammetric studies on the electrochemical behaviour of alkaline copper complexes, ...

  7. Testing Corrosion Inhibitors for the Conservation of Archaeological Copper and Copper Alloys

    Directory of Open Access Journals (Sweden)

    Robert B. Faltermeier

    1997-11-01

    Full Text Available This is a synopsis of the Ph.D. research undertaken at the Institute of Archaeology, University College London. The aim was to evaluate corrosion inhibitors for use in the conservation of copper and copper alloy archaeological artefacts. The objective of this work was to acquire an insight into the performance of copper corrosion inhibitors, when applied to archaeological copper.

  8. Copper tolerance of Trichoderma species

    Directory of Open Access Journals (Sweden)

    Jovičić-Petrović Jelena

    2014-01-01

    Full Text Available Some Trichoderma strains can persist in ecosystems with high concentrations of heavy metals. The aim of this research was to examine the variability of Trichoderma strains isolated from different ecosystems, based on their morphological properties and restriction analysis of ITS fragments. The fungal growth was tested on potato dextrose agar, amended with Cu(II concentrations ranging from 0.25 to 10 mmol/l, in order to identify copper-resistant strains. The results indicate that some isolated strains of Trichoderma sp. show tolerance to higher copper concentrations. Further research to examine the ability of copper bioaccumulation by tolerant Trichoderma strains is needed. [Projekat Ministarstva nauke Republike Srbije, br. TR 31080 i br. III 43010

  9. Mechanochemical reduction of copper sulfide

    DEFF Research Database (Denmark)

    Balaz, P.; Takacs, L.; Jiang, Jianzhong

    2002-01-01

    The mechanochemical reduction of copper sulfide with iron was induced in a Fritsch P-6 planetary mill, using WC vial filled with argon and WC balls. Samples milled for specific intervals were analyzed by XRD and Mossbauer spectroscopy. Most of the reaction takes place during the first 10 min...... of milling and only FeS and Cu are found after 60 min. The main chemical process is accompanied by phase transformations of the sulfide phases as a result of milling. Djurleite partially transformed to chalcocite and a tetragonal copper sulfide phase before reduction. The cubic modification of FeS was formed...... first, transforming to hexagonal during the later stages of the process. The formation of off-stoichiometric phases and the release of some elemental sulfur by copper sulfide are also probable....

  10. Laser sintering of copper nanoparticles

    International Nuclear Information System (INIS)

    Zenou, Michael; Saar, Amir; Ermak, Oleg; Kotler, Zvi

    2014-01-01

    Copper nanoparticle (NP) inks serve as an attractive potential replacement to silver NP inks in functional printing applications. However their tendency to rapidly oxidize has so far limited their wider use. In this work we have studied the conditions for laser sintering of Cu-NP inks in ambient conditions while avoiding oxidation. We have determined the regime for stable, low-resistivity copper (< ×3 bulk resistivity value) generation in terms of laser irradiance and exposure duration and have indicated the limits on fast processing. The role of pre-drying conditions on sintering outcome has also been studied. A method, based on spectral reflectivity measurements, was used for non-contact monitoring of the sintering process evolution. It also indicates preferred spectral regions for sintering. Finally, we illustrated how selective laser sintering can generate high-quality, fine line (<5 µm wide) and dense copper circuits. (paper)

  11. Membrane Lipid Peroxidation in Copper Alloy-Mediated Contact Killing of Escherichia coli

    Science.gov (United States)

    Hong, Robert; Kang, Tae Y.; Michels, Corinne A.

    2012-01-01

    Copper alloy surfaces are passive antimicrobial sanitizing agents that kill bacteria, fungi, and some viruses. Studies of the mechanism of contact killing in Escherichia coli implicate the membrane as the target, yet the specific component and underlying biochemistry remain unknown. This study explores the hypothesis that nonenzymatic peroxidation of membrane phospholipids is responsible for copper alloy-mediated surface killing. Lipid peroxidation was monitored with the thiobarbituric acid-reactive substances (TBARS) assay. Survival, TBARS levels, and DNA degradation were followed in cells exposed to copper alloy surfaces containing 60 to 99.90% copper or in medium containing CuSO4. In all cases, TBARS levels increased with copper exposure levels. Cells exposed to the highest copper content alloys, C11000 and C24000, exhibited novel characteristics. TBARS increased immediately at a very rapid rate but peaked at about 30 min. This peak was associated with the period of most rapid killing, loss in membrane integrity, and DNA degradation. DNA degradation is not the primary cause of copper-mediated surface killing. Cells exposed to the 60% copper alloy for 60 min had fully intact genomic DNA but no viable cells. In a fabR mutant strain with increased levels of unsaturated fatty acids, sensitivity to copper alloy surface-mediated killing increased, TBARS levels peaked earlier, and genomic DNA degradation occurred sooner than in the isogenic parental strain. Taken together, these results suggest that copper alloy surface-mediated killing of E. coli is triggered by nonenzymatic oxidative damage of membrane phospholipids that ultimately results in the loss of membrane integrity and cell death. PMID:22247141

  12. Structural models of the human copper P-type ATPases ATP7A and ATP7B

    DEFF Research Database (Denmark)

    Gourdon, Pontus Emanuel; Sitsel, Oleg; Karlsen, Jesper Lykkegaard

    2012-01-01

    The human copper exporters ATP7A and ATP7B contain domains common to all P-type ATPases as well as class-specific features such as six sequential heavy-metal binding domains (HMBD1-HMBD6) and a type-specific constellation of transmembrane helices. Despite the medical significance of ATP7A and ATP7B......, allowing protein-specific properties to be addressed. Furthermore, the mapping of known disease-causing missense mutations indicates that among the heavy-metal binding domains, HMBD5 and HMBD6 are the most crucial for function, thus mimicking the single or dual HMBDs found in most copper-specific P...

  13. Copper removal from acid mine drainage-polluted water using glutaraldehyde-polyethyleneimine modified diatomaceous earth particles

    Directory of Open Access Journals (Sweden)

    Mikael Larsson

    2018-02-01

    Full Text Available Mine waters and tailings generated from mining and mineral processing activities often have detrimental impact on the local environment. One example is acid mine drainage, in which sulphides in the mining waste react with water and oxygen to produce an acidic environment that subsequently dissolves host rock minerals from the waste containing toxic metals and trace elements. Copper is one such metal of significance, as it is mined at large volumes in sulphide containing ores. It has strong biocidal activity that greatly affects ecosystems. We have previously reported that glutaraldehyde (GA-crosslinked polyethyleneimine (PEI has strong affinity and selectivity for copper and that diatomaceous earth (DE particles can be modified with the material to form a copper-extraction resin. In this study, the copper uptake of GA-PEI-DE particles was investigated from synthetic and real acid mine drainage samples under different pHs and their copper removal performance was compared with that of selected commercial resins. The results revealed that copper could effectively and preferentially bind to the material at pH 4, and that the copper could be completely eluted by lowering of the pH. In addition, effective copper uptake and elution was demonstrated using real legacy acid mine drainage water from Mount Lyell in Tasmania.

  14. Copper removal from acid mine drainage-polluted water using glutaraldehyde-polyethyleneimine modified diatomaceous earth particles.

    Science.gov (United States)

    Larsson, Mikael; Nosrati, Ataollah; Kaur, Simarpreet; Wagner, Jochen; Baus, Ulf; Nydén, Magnus

    2018-02-01

    Mine waters and tailings generated from mining and mineral processing activities often have detrimental impact on the local environment. One example is acid mine drainage, in which sulphides in the mining waste react with water and oxygen to produce an acidic environment that subsequently dissolves host rock minerals from the waste containing toxic metals and trace elements. Copper is one such metal of significance, as it is mined at large volumes in sulphide containing ores. It has strong biocidal activity that greatly affects ecosystems. We have previously reported that glutaraldehyde (GA)-crosslinked polyethyleneimine (PEI) has strong affinity and selectivity for copper and that diatomaceous earth (DE) particles can be modified with the material to form a copper-extraction resin. In this study, the copper uptake of GA-PEI-DE particles was investigated from synthetic and real acid mine drainage samples under different pHs and their copper removal performance was compared with that of selected commercial resins. The results revealed that copper could effectively and preferentially bind to the material at pH 4, and that the copper could be completely eluted by lowering of the pH. In addition, effective copper uptake and elution was demonstrated using real legacy acid mine drainage water from Mount Lyell in Tasmania.

  15. Refining processes in the copper casting technology

    OpenAIRE

    Rzadkosz, S.; Kranc, M.; Garbacz-Klempka, A.; Kozana, J.; Piękoś, M.

    2015-01-01

    The paper presents the analysis of technology of copper and alloyed copper destined for power engineering casts. The casts quality was assessed based on microstructure, chemical content analysis and strength properties tests. Characteristic deoxidising (Logas, Cup) and modifying (ODM2, Kupmod2) formulas were used for the copper where high electrical conductivity was required. Chosen examples of alloyed copper with varied Cr and Zr content were studied, and the optimal heat treatment parameter...

  16. Impairment of interrelated iron- and copper homeostatic mechanisms in brain contributes to the pathogenesis of neurodegenerative disorders

    Directory of Open Access Journals (Sweden)

    Tina eSkjørringe

    2012-09-01

    Full Text Available Iron and copper are important co-factors for a number of enzymes in the brain, including enzymes involved in neurotransmitter synthesis and myelin formation. Both shortage and an excess of iron or copper will affect the brain. The transport of iron and copper into the brain from the circulation is strictly regulated, and concordantly protective barriers i.e. the blood-brain barrier (BBB and the blood-cerebrospinal fluid (CSF barrier (BCB have evolved to separate the brain environment from the circulation. The uptake mechanisms of the two metals interact. Both iron deficiency and overload lead to altered copper homeostasis in the brain. Similarly, changes in dietary copper affect the brain-iron homeostasis. Moreover, the uptake routes of iron and copper overlap each other which affect the interplay between the concentrations of the two metals in the brain. The divalent metal transporter-1 (DMT1 is involved in the uptake of both iron and copper. Furthermore, copper is an essential co-factor in numerous proteins that are vital for iron homeostasis and affects the binding of iron-response proteins to iron-response elements in the mRNA of the transferrin receptor, DMT1 and ferroportin, all highly involved in iron transport. Iron and copper are mainly taken up at the BBB, but the BCB also plays a vital role in the homeostasis of the two metals, in terms of sequestering, uptake and efflux of iron and copper from the brain. Inside the brain, iron and copper are taken up by neurons and glia cells that express various transporters

  17. Application of a generalized linear mixed model to analyze mixture toxicity: survival of brown trout affected by copper and zinc.

    Science.gov (United States)

    Iwasaki, Yuichi; Brinkman, Stephen F

    2015-04-01

    Increased concerns about the toxicity of chemical mixtures have led to greater emphasis on analyzing the interactions among the mixture components based on observed effects. The authors applied a generalized linear mixed model (GLMM) to analyze survival of brown trout (Salmo trutta) acutely exposed to metal mixtures that contained copper and zinc. Compared with dominant conventional approaches based on an assumption of concentration addition and the concentration of a chemical that causes x% effect (ECx), the GLMM approach has 2 major advantages. First, binary response variables such as survival can be modeled without any transformations, and thus sample size can be taken into consideration. Second, the importance of the chemical interaction can be tested in a simple statistical manner. Through this application, the authors investigated whether the estimated concentration of the 2 metals binding to humic acid, which is assumed to be a proxy of nonspecific biotic ligand sites, provided a better prediction of survival effects than dissolved and free-ion concentrations of metals. The results suggest that the estimated concentration of metals binding to humic acid is a better predictor of survival effects, and thus the metal competition at the ligands could be an important mechanism responsible for effects of metal mixtures. Application of the GLMM (and the generalized linear model) presents an alternative or complementary approach to analyzing mixture toxicity. © 2015 SETAC.

  18. Growth of Copper Production: Determinants and Empirical Evidence

    Directory of Open Access Journals (Sweden)

    Teodoro M. Santos

    2001-12-01

    Full Text Available From the 1950s to 1980, the copper mining industry exhibited a phenomenal growth rate. However, beginning in the early 1980s through 1997, growth rate turned negative without any sign of reversal. In order to restore the important role the industry used to play in the economy, policy makers, and decision makers must understand the factors responsible for the rapid growth from the 1950s until 1980 and the equally rapid decline during the 1980s and the 1990s.Growth of the copper mining industry is examined within the framework of a production function to identify the determinants of growth and their roles. The explanatory variables of growth are: copper resources, risk capital or investments, development in the world’s copper market, technology, human capital in mining, and domestic social, legal, and political environment. Except for copper resources, which has been supportive of positive growth, all the variables have components that supported the growth of the copper mining industry during the 1950s-1980s period and contributed to its decline thereafter.Availability of foreign capital, introduction of bulk mining technology, favorable copper prices and demand, and a conducive domestic social, political, and legal environment were responsible for the impressive growth experienced during the period from the 1950s to 1980. On the other hand, lack of foreign investment, declining market demand and prices, inadequate experience of local executives in the functions of top technical and managerial positions after 1974, arbitrary fiscal policies, lack of mining laws from 1986 to 1995, contradictory laws thereafter, and an uncertain domestic political, social, and legal environment caused the negative growth rates in the 1980s and 1990s. The 1995 Mining Code, which allows 100 percent foreign investments in mining under the financial and technical assistance mode of mineral disposition, could have revived the industry after 1995 were it allowed to

  19. Disorder effect on heat capacity, self-diffusion coefficient, and choosing best potential model for melting temperature, in gold–copper bimetallic nanocluster with 55 atoms

    International Nuclear Information System (INIS)

    Taherkhani, Farid; Akbarzadeh, Hamed; Feyzi, Mostafa; Rafiee, Hamid Reza

    2015-01-01

    Molecular dynamics simulation has been implemented for doping effect on melting temperature, heat capacity, self-diffusion coefficient of gold–copper bimetallic nanostructure with 55 total gold and copper atom numbers and its bulk alloy. Trend of melting temperature for gold–copper bimetallic nanocluster is not same as melting temperature copper–gold bulk alloy. Molecular dynamics simulation of our result regarding bulk melting temperature is consistence with available experimental data. Molecular dynamics simulation shows that melting temperature of gold–copper bimetallic nanocluster increases with copper atom fraction. Semi-empirical potential model and quantum Sutton–Chen potential models do not change melting temperature trend with copper doping of gold–copper bimetallic nanocluster. Self-diffusion coefficient of copper atom is greater than gold atom in gold–copper bimetallic nanocluster. Semi-empirical potential within the tight-binding second moment approximation as new application potential model for melting temperature of gold–copper bulk structure shows better result in comparison with EAM, Sutton–Chen potential, and quantum Sutton–Chen potential models

  20. Tunable synthesis of copper nanotubes

    International Nuclear Information System (INIS)

    Kaniukov, E; Yakimchuk, D; Kozlovsky, A; Shlimas, D; Zdorovets, M; Kadyrzhanov, K

    2016-01-01

    Simple method of tunable synthesis of copper nanotubes based on template synthesis was developed. A comprehensive study of the structural, morphological and electrical characteristics of the obtained nanostructures was carried out. Characterization of structural features was made by methods of scanning electron microscopy, energy dispersive spectroscopy and X-ray diffractometry analysis. Evaluation of wall thickness is made by methods of gas permeability. Electrical conductivity of nanotubes was define in the study of their current-voltage characteristics. The possibility to control of copper nanotubes physical properties by variation of the deposition parameters was shown. (paper)

  1. Electrical conduction in composites containing copper core–copper ...

    Indian Academy of Sciences (India)

    Unknown

    of Mott's small polaron hopping conduction model. ... sample exhibited a metallic conduction confirming the formation of a percolative chain of ..... value of εp. Also the oxide layer formation on the initially unoxidized copper particles will increase the resistivity level of the nanocomposite. This is borne out by results shown in ...

  2. Joining of alumina via copper/niobium/copper interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Marks, Robert A.; Chapman, Daniel R.; Danielson, David T.; Glaeser, Andreas M.

    2000-03-15

    Alumina has been joined at 1150 degrees C and 1400 degrees C using multilayer copper/niobium/copper interlayers. Four-point bend strengths are sensitive to processing temperature, bonding pressure, and furnace environment (ambient oxygen partial pressure). Under optimum conditions, joints with reproducibly high room temperature strengths (approximately equal 240 plus/minus 20 MPa) can be produced; most failures occur within the ceramic. Joints made with sapphire show that during bonding an initially continuous copper film undergoes a morphological instability, resulting in the formation of isolated copper-rich droplets/particles at the sapphire/interlayer interface, and extensive regions of direct bonding between sapphire and niobium. For optimized alumina bonds, bend tests at 800 degrees C-1100 degrees C indicate significant strength is retained; even at the highest test temperature, ceramic failure is observed. Post-bonding anneals at 1000 degrees C in vacuum or in gettered argon were used to assess joint stability and to probe the effect of ambient oxygen partial pressure on joint characteristics. Annealing in vacuum for up to 200 h causes no significant decrease in room temperature bend strength or change in fracture path. With increasing anneal time in a lower oxygen partial pressure environment, the fracture strength decreases only slightly, but the fracture path shifts from the ceramic to the interface.

  3. Structure transitions between copper-sulphate and copper-chloride ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Structure transitions between copper UPD adlayers on Au(111)–(1 × 1) in sulfuric acid and chloride containing electrolyte were investigated by in situ scanning tunnelling microscopy. We demon- strate that co-adsorbed sulphate ions in the (√3 × √3)R30° UPD adlayer are replaced by chloride ions and,.

  4. Two different modes for copper(II ion coordination to quinine-type ligands

    Directory of Open Access Journals (Sweden)

    Rey Nicolás A.

    2006-01-01

    Full Text Available Three new copper(II complexes with the ligands quinuclidine [Cu(C7H13N2(OH2Cl]Cl.2H 2O (1, quinine [Cu(C20H23O2N2(OH 22]ClO4 (2, and hydroquinidine [Cu(C20H27O2N2(OH 2 Cl2]Cl.fraction one-halfH2O (3 have been isolated and characterized. The binding sites were assigned on the basis of vibrational spectroscopy, electron paramagnetic resonance, and thermal analysis results. The possibility of the involvement of the quinuclidinic nitrogen in the coordination was evidenced in complex 1, in which copper(II is coordinated to two quinuclidine molecules. In the case of quinine-type ligands, if the starting material is deprotonated in both nitrogens, copper(II coordination occurs through the quinuclidinic nitrogen, as in complex 2. In contrast, if the starting material is protonated in the quinuclidinic nitrogen the binding site is the quinolinic nitrogen, as in complex 3. Therefore, both nitrogens of quinine-type ligands constitute binding sites for copper(II ions.

  5. Is there a link between selectivity and binding thermodynamics profiles?

    Science.gov (United States)

    Tarcsay, Ákos; Keserű, György M

    2015-01-01

    Thermodynamics of ligand binding is influenced by the interplay between enthalpy and entropy contributions of the binding event. The impact of these binding free energy components, however, is not limited to the primary target only. Here, we investigate the relationship between binding thermodynamics and selectivity profiles by combining publicly available data from broad off-target assay profiling and the corresponding thermodynamics measurements. Our analysis indicates that compounds binding their primary targets with higher entropy contributions tend to hit more off-targets compared with those ligands that demonstrated enthalpy-driven binding. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. A copper vapor laser by using a copper-vapor-complex reaction at a low temperature

    OpenAIRE

    Kano, Toshiyuki; Taniguchi, Hiroshi; Saito, Hiroshi

    1987-01-01

    A copper vapor laser performance by using ametal-vapor-complex reaction (Cu+AlBr3) is reported. The laser operation is obtained at a low temperature without externalheating because of the AlBr3 vapors evaporating at a room temperature. The copper vapor laser using this metal-vapor-complex reaction has an advantage of deposition-free of a metallic copper to the laser tube wall, which is different from the copper halide and the organometallic copper lasers.

  7. Durability evaluation of superhydrophobic copper foams for long-term oil-water separation

    Science.gov (United States)

    Zhu, Haiyan; Gao, Lin; Yu, Xinquan; Liang, Caihua; Zhang, Youfa

    2017-06-01

    Superhydrophobic three-dimensional porous composites with good mechanical stability and high efficiency are promising candidates for oil-water separation application. Hence, several superhydrophobic copper foams were fabricated via the in situ growth of patterned Cu(OH)2 nanoneedles or ZnO nanocrystals (e.g. ZnO nanocones and ZnO nanorods) on the skeleton and followed by chemically modification. All the superhydrophobic copper foams showed efficient oil-water separation ability, especially the samples with ZnO nanorods arrays on the pre-nanostructured skeleton. The durability of superhydrophobic copper foams were then evaluated. Although the superhydrophobic samples kept separation efficiency higher than 95% after cycled evaluation, the pre-roughened copper foams exhibited the best performance against various damage among the samples. Microstructural evolution revealed that the coverage of the copper skeleton became from smooth swelling micro-crystals into rough nano-crystals after the pre-treatment of electrodepositing copper nanoparticles. The rough nanocrystals could not only avoid the formation of loose hierarchical structure, but also improve the binding force between patterned nanorods and the matrix. The fabricated closely-patterned ZnO nanorods could thus remain stable under the damage compared to others, presenting great mechanical robustness. Furthermore, we achieved a long-term efficient oil-water separation using the durable foams by periodic removal of residual oil in nanostructure gaps.

  8. Utilizing NMR and EPR spectroscopy to probe the role of copper in prion diseases

    KAUST Repository

    Emwas, Abdul-Hamid M.

    2013-02-24

    Copper is an essential nutrient for the normal development of the brain and nervous system, although the hallmark of several neurological diseases is a change in copper concentrations in the brain and central nervous system. Prion protein (PrP) is a copper-binding, cell-surface glycoprotein that exists in two alternatively folded conformations: a normal isoform (PrPC) and a disease-associated isoform (PrPSc). Prion diseases are a group of lethal neurodegenerative disorders that develop as a result of conformational conversion of PrPC into PrPSc. The pathogenic mechanism that triggers this conformational transformation with the subsequent development of prion diseases remains unclear. It has, however, been shown repeatedly that copper plays a significant functional role in the conformational conversion of prion proteins. In this review, we focus on current research that seeks to clarify the conformational changes associated with prion diseases and the role of copper in this mechanism, with emphasis on the latest applications of NMR and EPR spectroscopy to probe the interactions of copper with prion proteins. Copyright © 2013 John Wiley & Sons, Ltd.

  9. Copper absorption from human milk, cow's milk, and infant formulas using a suckling rat model

    International Nuclear Information System (INIS)

    Loennerdal, B.B.; Bell, J.G.; Keen, C.L.

    1985-01-01

    Since copper deficiency is known to occur during infancy, it becomes important to assess copper uptake from various infant diets. The authors have investigated the uptake of copper from human milk, cow's milk, cow's milk formulas, cereal/milk formula and soy formula, compensating for the decay of 64 Cu and using the suckling rat as a model. Radiocopper was added to the diet in trace amounts. Ultracentrifugation, ultrafiltration, and gel filtration were used to show that the added 64 Cu bound to milk fractions and individual binding compounds in a manner analogous to the distribution of native copper, thus validating the use of extrinsically labeled diets. Labeled diets were intubated into 14-day-old suckling rats. Animals were killed after 6 h and tissues removed and counted. Liver copper uptake was 25% from human milk, 23% from cow's milk formula, 18% from cow's milk, 17% from premature (cow's milk based) infant formula, 17% from cereal/milk formula and 10% from soy formula. These results show that the rat pup model may provide a rapid, inexpensive, and sensitive method to assay bioavailability of copper from infant foods

  10. Use of ancient copper slags in Portland cement and alkali activated cement matrices.

    Science.gov (United States)

    Nazer, Amin; Payá, Jordi; Borrachero, María Victoria; Monzó, José

    2016-02-01

    Some Chilean copper slag dumps from the nineteenth century still remain, without a proposed use that encourages recycling and reduces environmental impact. In this paper, the copper slag abandoned in landfills is proposed as a new building material. The slags studied were taken from Playa Negra and Púquios dumps, both located in the region of Atacama in northern Chile. Pozzolanic activity in lime and Portland cement systems, as well as the alkali activation in pastes with copper slag cured at different temperatures, was studied. The reactivity of the slag was measured using thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), electrical conductivity and pH in aqueous suspension and Fourier Transform Infrared Spectroscopy (FTIR). Furthermore, copper slag-Portland cement mortars with the substitution of 25% (by weight) of cement by copper slag and alkali-activated slag mortars cured at 20 and 65 °C were made, to determine the compressive strength. The results indicate that the ancient copper slags studied have interesting binding properties for the construction sector. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Species dependence of [64Cu]Cu-Bis(thiosemicarbazone) radiopharmaceutical binding to serum albumins

    International Nuclear Information System (INIS)

    Basken, Nathan E.; Mathias, Carla J.; Lipka, Alexander E.; Green, Mark A.

    2008-01-01

    Introduction: Interactions of three copper(II) bis(thiosemicarbazone) positron emission tomography radiopharmaceuticals with human serum albumin, and the serum albumins of four additional mammalian species, were evaluated. Methods: 64 Cu-labeled diacetyl bis(N 4 -methylthiosemicarbazonato)copper(II) (Cu-ATSM), pyruvaldehyde bis(N 4 -methylthiosemicarbazonato)copper(II) (Cu-PTSM) and ethylglyoxal bis(thiosemicarbazonato)copper(II) (Cu-ETS) were synthesized and their binding to human, canine, rat, baboon and porcine serum albumins quantified by ultrafiltration. Protein binding was also measured for each tracer in human, porcine, rat and mouse serum. Results: The interaction of these neutral, lipophilic copper chelates with serum albumin is highly compound- and species-dependent. Cu-PTSM and Cu-ATSM exhibit particularly high affinity for human serum albumin (HSA), while the albumin binding of Cu-ETS is relatively insensitive to species. At HSA concentrations of 40 mg/ml, '% free' (non-albumin-bound) levels of radiopharmaceutical were 4.0±0.1%, 5.3±0.2% and 38.6±0.8% for Cu-PTSM, Cu-ATSM and Cu-ETS, respectively. Conclusions: Species-dependent variations in radiopharmaceutical binding to serum albumin may need to be considered when using animal models to predict the distribution and kinetics of these compounds in humans

  12. Copper-induced immunotoxicity involves cell cycle arrest and cell death in the spleen and thymus

    International Nuclear Information System (INIS)

    Mitra, Soham; Keswani, Tarun; Dey, Manali; Bhattacharya, Shaswati; Sarkar, Samrat; Goswami, Suranjana; Ghosh, Nabanita; Dutta, Anuradha; Bhattacharyya, Arindam

    2012-01-01

    Copper is an essential trace element for human physiological processes. To evaluate the potential adverse health impact/immunotoxicological effects of this metal in situ due to over exposure, Swiss albino mice were treated (via intraperitoneal injections) with copper (II) chloride (copper chloride) at doses of 0, 5, or 7.5 mg copper chloride/kg body weight (b.w.) twice a week for 4 wk; these values were derived from LD 50 studies using copper chloride doses that ranged from 0 to 40 mg/kg BW (2×/wk, for 4 wk). Copper treated mice evidenced immunotoxicity as indicated by dose-related decreases and increases, respectively, in thymic and splenic weights. Histomorphological changes evidenced in these organs were thymic atrophy, white pulp shrinkage in the spleen, and apoptosis of splenocytes and thymocytes; these observations were confirmed by microscopic analyses. Cell count analyses indicated that the proliferative functions of the splenocytes and thymocytes were also altered because of the copper exposures. Among both cell types from the copper treated hosts, flow cytometric analyses revealed a dose related increase in the percentages of cells in the Sub-G 0 /G 1 state, indicative of apoptosis which was further confirmed by Annexin V binding assay. In addition, the copper treatments altered the expression of selected cell death related genes such as EndoG and Bax in a dose related manner. Immunohistochemical analyses revealed that there was also increased ubiquitin expression in both the cell types. In conclusion, these studies show that sublethal exposure to copper (as copper chloride) induces toxicity in the thymus and spleen, and increased Sub G 0 /G 1 population among splenocytes and thymocytes that is mediated, in part, by the EndoG–Bax–ubiquitin pathway. This latter damage to these cells that reside in critical immune system organs are likely to be important contributing factors underlying the immunosuppression that has been documented by other

  13. Marine Microcosm Experiments on Effects of Copper and Tributylin-Based Antifouling Paint Leachates

    Science.gov (United States)

    1988-06-01

    SPC-4 treatment. The increased aggregation of diatoms was attributed to potential binding effects of a higher than normal secretion of mucilage by the...Technical Report 1060 June 1988 00 Marine Microcosm Experiments on 2TiC’ Effects of Copper kE LECTE wm% and Tributyltin-Based Antifouling Paint D... EFFECTS OF COPPER AND TRIBUTYLTIN-BASED ANTIFOUALING PAINT LEACHATES 12. PERSONAL AUTHOR (S) R. Scott Henderson F4DT 5PG ON13a. TYPE OF REPORT 13b TIME

  14. Controlled synthesis of water-dispersible faceted crystalline copper nanoparticles and their catalytic properties.

    Science.gov (United States)

    Wang, Yanfei; Biradar, Ankush V; Wang, Gang; Sharma, Krishna K; Duncan, Cole T; Rangan, Sylvie; Asefa, Tewodros

    2010-09-17

    We report a solution-phase synthetic route to copper nanoparticles with controllable size and shape. The synthesis of the nanoparticles is achieved by the reduction of copper(II) salt in aqueous solution with hydrazine under air atmosphere in the presence of poly(acrylic acid) (PAA) as capping agent. The results suggest that the pH plays a key role for the formation of pure copper nanoparticles, whereas the concentration of PAA is important for controlling the size and geometric shape of the nanoparticles. The average size of the copper nanoparticles can be varied from 30 to 80 nm, depending on the concentration of PAA. With a moderate amount of PAA, faceted crystalline copper nanoparticles are obtained. The as-synthesized copper nanoparticles appear red in color and are stable for weeks, as confirmed by UV/Vis and X-ray photoemission (XPS) spectroscopy. The faceted crystalline copper nanoparticles serve as an effective catalyst for N-arylation of heterocycles, such as the C--N coupling reaction between p-nitrobenzyl chloride and morpholine producing 4-(4-nitrophenyl)morpholine in an excellent yield under mild reaction conditions. Furthermore, the nanoparticles are proven to be versatile as they also effectively catalyze the three-component, one-pot Mannich reaction between p-substituted benzaldehyde, aniline, and acetophenone affording a 100% conversion of the limiting reactant (aniline).

  15. Lead, copper and zinc biosorption from bicomponent systems modelled by empirical Freundlich isotherm

    Energy Technology Data Exchange (ETDEWEB)

    Sag, Y.; Kaya, A.; Kutsal, T. [Dept. of Chemical Engineering, Hacettepe Univ., Beytepe, Ankara (Turkey)

    2000-07-01

    The biosorption of lead, copper and zinc ions on Rhizopus arrhizus has been studied for three single-component and two binary systems. The equilibrium data have been analysed using the Freundlich adsorption model. The characteristic parameters for the Freundlich adsorption model have been determined and the competition coefficients for the competitive biosorption of Pb(II)-Cu(II) at pH 4.0 and 5.0, and Pb(II)-Zn(II) at pH 5.0 have been calcualted. For the individual single-component isotherms, lead has the highest biosorption capacity followed by copper, then zinc. The capacity of lead in the two binary systems is always significantly greater than those of the other metal ions, in agreement with the single-component data. Only a partial selectivity for copper ions has been obtained at pH 4.0. (orig.)

  16. on THICKNESS OF COPPER (|) OXIDE

    African Journals Online (AJOL)

    2006-12-20

    Dec 20, 2006 ... semiconductor devices. The oxide is. Observed to be an attractive starting material for the production of solar cells for low cost terrestrial conversion of solar energy to electricity. Copper (I) oxide is one Of the earliest known photovoltaic materials and the first in which the photovOltaic effect was successfully ...

  17. Evaluation of Cu(i) binding to the E2 domain of the amyloid precursor protein - a lesson in quantification of metal binding to proteins via ligand competition.

    Science.gov (United States)

    Young, Tessa R; Wedd, Anthony G; Xiao, Zhiguang

    2018-01-24

    The extracellular domain E2 of the amyloid precursor protein (APP) features a His-rich metal-binding site (denoted as the M1 site). In conjunction with surrounding basic residues, the site participates in interactions with components of the extracellular matrix including heparins, a class of negatively charged polysaccharide molecules of varying length. This work studied the chemistry of Cu(i) binding to APP E2 with the probe ligands Bcs, Bca, Fz and Fs. APP E2 forms a stable Cu(i)-mediated ternary complex with each of these anionic ligands. The complex with Bca was selected for isolation and characterization and was demonstrated, by native ESI-MS analysis, to have the stoichiometry E2 : Cu(i) : Bca = 1 : 1 : 1. Formation of these ternary complexes is specific for the APP E2 domain and requires Cu(i) coordination to the M1 site. Mutation of the M1 site was consistent with the His ligands being part of the E2 ligand set. It is likely that interactions between the negatively charged probe ligands and a positively charged patch on the surface of APP E2 are one aspect of the generation of the stable ternary complexes. Their formation prevented meaningful quantification of the affinity of Cu(i) binding to the M1 site with these probe ligands. However, the ternary complexes are disrupted by heparin, allowing reliable determination of a picomolar Cu(i) affinity for the E2/heparin complex with the Fz or Bca probe ligands. This is the first documented example of the formation of stable ternary complexes between a Cu(i) binding protein and a probe ligand. The ready disruption of the complexes by heparin identified clear 'tell-tale' signs for diagnosis of ternary complex formation and allowed a systematic review of conditions and criteria for reliable determination of affinities for metal binding via ligand competition. This study also provides new insights into a potential correlation of APP functions regulated by copper binding and heparin interaction.

  18. A Study of Protection of Copper Alloys

    International Nuclear Information System (INIS)

    Kim, E. A.; Kim, S. H.; Kim, C. R.

    1974-01-01

    Volatile treatment of high capacity boiler water with hydrazine and ammonia is studied. Ammonia comes from the decomposition of excess hydrazine injected to treat dissolved oxygen. Ammonia is also injected for the control of pH. To find an effect of such ammonia on the copper alloy, the relations between pH and iron, and ammonia and copper are studied. Since the dependence of corrosion of iron on pH differs from that of copper, a range of pH was selected experimentally to minimize the corrosion rates of both copper and iron. Corrosion rates of various copper alloys are also compared

  19. Chronic copper toxicity in a dairy herd

    OpenAIRE

    Perrin, David J.; Schiefer, H. Bruno; Blakley, Barry R.

    1990-01-01

    The addition of excessive copper to a commercially prepared dairy ration caused chronic copper toxicity in a dairy herd. A formulation error by a feed company resulted in copper levels of 800 to 1,000 mg/kg in the “as fed concentrate,” amounting to about 400-500 mg copper/kg of the whole ration. Five animals died with typical signs of acute copper toxicity, including intravascular hemolysis and methemoglobinemia. A further 39 cows died on the farm from a combination of debilitation and second...

  20. Oral Fusobacterium nucleatum subsp. polymorphum binds to human salivary α-amylase.

    Science.gov (United States)

    Zulfiqar, M; Yamaguchi, T; Sato, S; Oho, T

    2013-12-01

    Fusobacterium nucleatum acts as an intermediate between early and late colonizers in the oral cavity. In this study, we showed that F. nucleatum subsp. polymorphum can bind to a salivary component with a molecular weight of approximately 110 kDa and identified the protein and another major factor of 55 kDa, as salivary α-amylase by time-of-flight mass spectrometry and immuno-reactions. Salivary α-amylase is present in both monomeric and dimeric forms and we found that formation of the dimer depends on copper ions. The F. nucleatum adhered to both monomeric and dimeric salivary α-amylases, but the numbers of bacteria bound to the dimeric form were more than those bound to the monomeric form. The degree of adherence of F. nucleatum to four α-amylases from different sources was almost the same, however its binding to β-amylase was considerably decreased. Among four α-amylase inhibitors tested, acarbose and type 1 and 3 inhibitors derived from wheat flour showed significant activity against the adhesion of F.nucleatum to monomeric and dimeric amylases, however voglibose had little effect. Moreover F. nucleatum cells inhibited the enzymatic activity of salivary α-amylase in a dose-dependent manner. These results suggest that F. nucleatum plays more important and positive role as an early colonizer for maturation of oral microbial colonization. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Control of biofouling on titanium condenser tubes with the use of electroless copper plating

    International Nuclear Information System (INIS)

    Anandkumar, B.; George, R.P.; Kamachi Mudali, U.; Ramachandran, D.

    2015-01-01

    In sea water environments titanium condenser tubes face serious issues of biofouling and biomineralization. Electroless plating of nanocopper film is attempted inside the tubes for the control of biofilm formation. Using advanced techniques like AFM, SEM, and XPS, electroless copper plated flat Ti specimens were characterized. Examination of Cu coated Ti surfaces using AFM and SEM showed more reduction in the microroughness compared to anodized Ti surface. Cu 2p 3/2 peak in XPS spectral analysis showed the shift in binding energy inferring the reduction of the hydroxide to metallic copper. Tubular specimens were exposed to sea water up to three months and withdrawn at monthly intervals to evaluate antibacterial activity and long term stability of the coating. Total viable counts and epifluorescence microscopy analyses showed two orders decrease in bacterial counts on copper coated Ti specimens when compared to as polished control Ti specimens. Molecular biology techniques like DGGE and protein expression analysis system were done to get insight into the community diversity and copper tolerance of microorganisms. DGGE gel bands clearly showed the difference in the bacterial diversity inferring from the 16S rRNA gene fragments (V3 regions). Protein analysis showed distinct protein spots appearing in electroless copper coated Ti biofilm protein samples in addition to protein spots common to both the biofilms of Cu coated and as polished Ti. The results indicated copper accumulating proteins in copper resistant bacterial species of biofilm. Reduced microroughness of the surface and toxic copper ions resulted in good biofouling control even after three months exposure to sea water. (author)

  2. Effects induced by LHC high energy beam in copper structures

    CERN Document Server

    Peroni, L; Dallocchio, A

    2011-01-01

    This study is performed in order to estimate the damage on copper components due to the impact of a 7 TeV proton beam in the Large Hadron Collider. The case study represents an accidental case consequent to an abnormal release of the beam, in which eight bunches impact directly the copper. The energy delivered on the components is calculated by the FLUKA Team at CERN using their Monte-Carlo code for calculation of particle transport and interactions with matter. The energy maps are used by the authors as input for the structural simulations carried out via the FEM code LS-DYNA. The evolution of the phenomenon is quite similar to what might happen during an explosion. The impacted part of the component reaches extremely high values of pressure and temperature and undergoes changes of state. The sudden increase in pressure originates outgoing shockwaves that, travelling through the component, lead to a substantial density reduction in the impacted part. The energy delivered on the component is sufficient to sev...

  3. Effects of light and copper ions on volatile aldehydes of milk and milk fractions

    Energy Technology Data Exchange (ETDEWEB)

    Jeno, W.; Bassette, R.; Crang, R.E.

    1988-09-01

    Raw, laboratory-pasteurized and plant-pasteurized homogenized milks were exposed to copper ions (5 ppm), to sunlight or fluorescent light and the effects determined on the composition of volatile aldehydes. The greatest change due to copper treatment was an increase in n-hexanal; acetaldehyde showed the least response in each of the sources of milk. The responses were similar from all three sources of milk with laboratory-pasteurized milk samples showing the greatest responses for each aldehyde analyzed. Similar milk samples exposed to sunlight also showed an increase in volatile aldehydes from all milk sources but with the greatest response being acetaldehyde and n-pentanal components. The milk fraction most susceptible to changes in the presence of light was neutralized whey, whereas resuspended cream was most susceptible to copper exposure. Overall, dialyzed whey appeared to be influenced more than other milk fractions by both light and copper ions.

  4. Structure and mechanical properties of a hybrid material with copper matrix and steel fibers after ECAP

    Science.gov (United States)

    Stanislav, Rogachev; Sergey, Nikulin; Vladimir, Khatkevich; Alexey, Molyarov; Alexander, Komissarov; Kseniya, Utkina

    2017-12-01

    The structure and mechanical properties of a hybrid material with a copper matrix and steel fibers subjected to ECAP were studied. C12200 pure copper and AISI 304 steel were used as hybrid material components. A mixed submicrocrystalline grain-subgrain structure with a high dislocation density is formed in the copper matrix of the hybrid material as a result of ECAP that leads to an increase in strength by ~20% while maintaining a high value of the relative elongation. The strength of the steel fibers of the hybrid material after ECAP was significantly increased primarily due to the process of intensive deformation twinning and increase in the dislocation density. At the same time, the presence of a ductile copper matrix around the steel fibers makes it difficult for them to shear strain during ECAP, which slows down the process of a developed ultrafine-grained structure formation.

  5. Copper-cadmium interaction in mice: effects of copper status on retention and distribution of cadmium after cadmium exposure

    International Nuclear Information System (INIS)

    Bourcier, D.R.

    1982-01-01

    The role of increased dietary copper in altering the accumulation of cadmium and other metals in tissues, was investigated. Female Swiss-Webster mice were pretreated with cadmium or copper in drinking water for three weeks prior to cadmium exposure for an additional nine weeks, with sub groups from each dose level receiving Cu additions to the Cd supplemented water. In Cd pretreated animals, a significant decrease was observed in Cd concentrations in liver and kidney when Cu was added to Cd in drinking water. Cadmium levels in soluble protein fractions of liver of animals administered 5 ppm Cd were approximately three fold greater than that for the same Cd dose when Cu was added. The same was the case for the metallothionein-like protein fraction (MTP) of the liver cytosol. In copper pretreated animals similar trends were noted in that brain, spleen, liver (but not kidney) Cd levels were decreased in animals receiving Cu additions to the Cd dose. Increased binding of Cd to the MTP fraction was observed after both in vivo and in vitro exposure of intestinal mucosal cells to cadmium

  6. Total iron binding capacity

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003489.htm Total iron binding capacity To use the sharing features on this page, please enable JavaScript. Total iron binding capacity (TIBC) is a blood test to ...

  7. Serum copper and ceruloplasmin levels and urinary copper excretion in thermal injury.

    Science.gov (United States)

    Boosalis, M G; McCall, J T; Solem, L D; Ahrenholz, D H; McClain, C J

    1986-12-01

    Conflicting reports regarding copper status in thermal injury patients have been published. We determined serial serum-copper and serum-ceruloplasmin levels and 24-h urinary excretion of copper in 23 patients with second- and third-degree thermal burns. Throughout hospitalization, mean serum-copper concentration was significantly depressed; lowest levels were found in patients with greater than 40% total body surface area burns. Serum ceruloplasmin was also depressed, an unexpected finding because this protein is a positive acute-phase reactant poststress. Mean urinary excretion of copper was elevated, reaching 2.5 times the upper limit of normal 2 wk postburn. Depressed serum-copper levels paralleled the serum-ceruloplasmin levels rather than the increased urinary-copper losses. Further studies are required to determine the mechanism(s) of this altered copper metabolism and whether physiological or biochemical evidence of copper deficiency accompanies the observed hypocupremia.

  8. Variations of serum copper values in pregnancy

    Directory of Open Access Journals (Sweden)

    Vukelić Jelka

    2012-01-01

    Full Text Available Introduction. Copper is essential micronutrient and has an important role in the human body. The serum copper increases during pregnancy and is doubled at full term. Lower levels of serum copper in pregnancy are connected with some pathological conditions. Objective. The aim of this study was to estimate the levels of serum copper in normal and pathological pregnancies, comparing them with values of serum copper in non-pregnant women, to determine if serum copper is lower in some pathological pregnancies and if this is of some importance. Methods. A total of 2170 plasma samples for copper analyses were made in the following groups: healthy non-pregnant women; healthy pregnant women from the 5th-40th gestational week, during the first delivery stage and during the first three postpartum weeks, in pregnant women with habitual abortion, imminent abortion, abortion in progress, missed abortion (9th-24th weeks, missed labour and premature rupture of membranes (29th-40th weeks. Levels of serum copper were determined by colorimetric technique of bathocuproin with disulphate as a chromogen. Results. Serum copper values in non-pregnant women range from 11.6-25.8 μmol/L. In healthy pregnant women, there is a constant trend of the increase of serum copper. The mean serum copper values revealed three significant peaks at the 22nd, 27th and 35th gestational week. Serum copper values in the patients with some pathological pregnancies in relation to the serum copper values of the healthy pregnant women were significantly lower. Conclusion. Serum copper values can be used as an indicator of some pathological pregnancies.

  9. Recycling of copper used in fusion power plants

    International Nuclear Information System (INIS)

    Forty, C.B.A.; Butterworth, G.J.; Turner, A.D.; Junkison, A.J.

    1997-04-01

    One of the major safety and environmental advantages of fusion power is a limited waste management burden on future generations. In this connection, the ability to recycle end-of-service materials from fusion power plant is beneficial both in terms of the conservation of natural resources and the minimisation of the volumes of activated wastes. After 100 years, the residual activity of near-plasma copper components exceeds that permitted for free release or contact handling. The presence of silver as a common impurity in copper may exacerbate this problem, through generation of 108m Ag. Removal of the silver impurity in a separate refining step prior to use of the copper in a fusion plant obviates the problems associated with formation of 108m Ag. Two alternative desilveration processes have been demonstrated; one involving the segregation of silver as AgBr and the other the absorption of Ag + by ion exchange. The present study demonstrates that conventional electrorefining techniques can be adapted to recover used copper in a single refining stage, with sufficient decontamination to permit its reuse in fusion power plants or, with a second stage, unrestricted release. Shielding requirements for the processing of scrap copper in conventional hot cells indicate a decay storage period of 50-100 years. To maximise the cost of savings of reclamation over direct geological disposal, the activation products may be separated out and disposed of in a metallic form. A substantial reduction in the overall volume of active waste should thus be achievable, especially if supercompaction can be applied to the product. (Author)

  10. Recycling of copper used in fusion power plants

    International Nuclear Information System (INIS)

    Butterworth, G.J.; Forty, C.B.A.

    1998-01-01

    One of the major safety and environmental advantages of fusion power is a limited waste management burden on future generations. In this connection, the ability to recycle end-of-service materials from fusion power plants is beneficial both in terms of the conservation of natural resources and the minimisation of the volume of activated wastes. After 100 years, the residual activity of near-plasma copper components exceeds that permitted for free release or contact handling. The presence of silver as a common impurity in copper may exacerbate this problem, through generation of 108m Ag. Removal of the silver impurity in a separate refining step prior to use of the copper in a fusion plant obviates the problems associated with formation of 108m Ag. Two alternative desilverisation processes have been demonstrated; one involving the segregation of silver as AgBr and the other the absorption of Ag + by ion exchange. The present study demonstrates that conventional electrorefining techniques can be adapted to recover used copper in a single refining stage, with sufficient decontamination to permit its reuse in fusion power plants or, with a second stage, unrestricted release. Shielding requirements for the processing of scrap copper in conventional hot cells indicate a decay storage period of 50-100 years. To maximise the cost savings of reclamation over direct geological disposal, the activation products may be separated out and disposed of in a metallic form. A substantial reduction in the overall volume of active waste should thus be achievable, especially if supercompaction can be applied to the product. (orig.)

  11. Synthetic LPS-Binding Polymer Nanoparticles

    Science.gov (United States)

    Jiang, Tian

    Lipopolysaccharide (LPS), one of the principal components of most gram-negative bacteria's outer membrane, is a type of contaminant that can be frequently found in recombinant DNA products. Because of its strong and even lethal biological effects, selective LPS removal from bioproducts solution is of particular importance in the pharmaceutical and health care industries. In this thesis, for the first time, a proof-of-concept study on preparing LPS-binding hydrogel-like NPs through facile one-step free-radical polymerization was presented. With the incorporation of various hydrophobic (TBAm), cationic (APM, GUA) monomers and cross-linkers (BIS, PEG), a small library of NPs was constructed. Their FITC-LPS binding behaviors were investigated and compared with those of commercially available LPS-binding products. Moreover, the LPS binding selectivity of the NPs was also explored by studying the NPs-BSA interactions. The results showed that all NPs obtained generally presented higher FITC-LPS binding capacity in lower ionic strength buffer than higher ionic strength. However, unlike commercial poly-lysine cellulose and polymyxin B agarose beads' nearly linear increase of FITC-LPS binding with particle concentration, NPs exhibited serious aggregation and the binding quickly saturated or even decreased at high particle concentration. Among various types of NPs, higher FITC-LPS binding capacity was observed for those containing more hydrophobic monomers (TBAm). However, surprisingly, more cationic NPs with higher content of APM exhibited decreased FITC-LPS binding in high ionic strength conditions. Additionally, when new cationic monomer and cross-linker, GUA and PEG, were applied to replace APM and BIS, the obtained NPs showed improved FITC-LPS binding capacity at low NP concentration. But compared with APM- and BIS-containing NPs, the FITC-LPS binding capacity of GUA- and PEG-containing NPs saturated earlier. To investigate the NPs' binding to proteins, we tested the NPs

  12. Intercalation processes of copper complexes in DNA

    Science.gov (United States)

    Galindo-Murillo, Rodrigo; García-Ramos, Juan Carlos; Ruiz-Azuara, Lena; Cheatham, Thomas E.; Cortés-Guzmán, Fernando

    2015-01-01

    The family of anticancer complexes that include the transition metal copper known as Casiopeínas® shows promising results. Two of these complexes are currently in clinical trials. The interaction of these compounds with DNA has been observed experimentally and several hypotheses regarding the mechanism of action have been developed, and these include the generation of reactive oxygen species, phosphate hydrolysis and/or base-pair intercalation. To advance in the understanding on how these ligands interact with DNA, we present a molecular dynamics study of 21 Casiopeínas with a DNA dodecamer using 10 μs of simulation time for each compound. All the complexes were manually inserted into the minor groove as the starting point of the simulations. The binding energy of each complex and the observed representative type of interaction between the ligand and the DNA is reported. With this extended sampling time, we found that four of the compounds spontaneously flipped open a base pair and moved inside the resulting cavity and four compounds formed stacking interactions with the terminal base pairs. The complexes that formed the intercalation pocket led to more stable interactions. PMID:25958394

  13. Nitric acid recycling and copper nitrate recovery from effluent.

    Science.gov (United States)

    Jô, L F; Marcus, R; Marcelin, O

    2014-01-01

    The recycling of nitric acid and copper nitrate contained in an industrial effluent was studied. The experiments conducted on such a medium showed that the presence of copper nitrate significantly improves nitric acid-water separation during distillation in an azeotropic medium. At the temperature of the azeotrope, however, this metal salt starts to precipitate, making the medium pasty, thus inhibiting the nitric acid extraction process. The optimisation of parameters such as column efficiency and adding water to the boiler at the azeotrope temperature are recommended in this protocol in order to collect the various components while avoiding the formation of by-products: NOx compounds. Thus, the absence of column, along with the addition of a small volume of water at a temperature of 118 °C, significantly increases the yield, allowing 94 % nitric acid to be recovered at the end of the process, along with the residual copper nitrate. The resulting distillate, however, is sufficiently dilute to not be used as is. Rectification is required to obtain concentrated nitric acid at 15 mol·l(-1), along with a weakly acidic distillate from the distillation front. This latter is quenched using potassium hydroxide and is used as a fertiliser solution for horticulture or sheltered market gardening. This process thus allows complete recycling of all the medium's components, including that of the distillate resulting from the nitric acid rectification operation.

  14. Druggability of methyl-lysine binding sites

    Science.gov (United States)

    Santiago, C.; Nguyen, K.; Schapira, M.

    2011-12-01

    Structural modules that specifically recognize—or read—methylated or acetylated lysine residues on histone peptides are important components of chromatin-mediated signaling and epigenetic regulation of gene expression. Deregulation of epigenetic mechanisms is associated with disease conditions, and antagonists of acetyl-lysine binding bromodomains are efficacious in animal models of cancer and inflammation, but little is known regarding the druggability of methyl-lysine binding modules. We conducted a systematic structural analysis of readers of methyl marks and derived a predictive druggability landscape of methyl-lysine binding modules. We show that these target classes are generally less druggable than bromodomains, but that some proteins stand as notable exceptions.

  15. Copper scandium zirconium phosphate

    DEFF Research Database (Denmark)

    Bond, Andrew David; Warner, Terence Edwin

    2013-01-01

    The title compound, with nominal formula Cu(2)ScZr(PO(4))(3), has a beige coloration and displays fast Cu(+) cation conduction at elevated temperatures. It adopts a NASICON-type structure in the space group R3c. The examined crystal was an obverse-reverse twin with approximately equal twin...... components. The [Sc(III)Zr(IV)(PO(4))(3)](2-) framework is composed of corner-sharing Sc/ZrO(6) octahedra and PO(4) tetrahedra. The Sc and Zr atoms are disordered on one atomic site on a crystallographic threefold axis. The P atom of the phosphate group lies on a crystallographic twofold axis. Nonframework...... Cu(+) cations occupy three positions. Two of the Cu(+) positions generate an approximately circular distribution around a site of 3 symmetry, referred to as the M1 site in the NASICON-type structure. The other Cu(+) position is situated close to the twofold symmetric M2 site, displaced...

  16. Vitamin B12 Phosphate Conjugation and Its Effect on Binding to the Human B12 -Binding Proteins Intrinsic Factor and Haptocorrin

    DEFF Research Database (Denmark)

    Ó Proinsias, Keith; Ociepa, Michał; Pluta, Katarzyna

    2016-01-01

    and its limitations examined. The resulting derivatives, particularly those bearing terminal alkyne and azide groups, were isolated and used in copper-catalyzed alkyne-azide cycloaddition reactions (CuAAC). Their sensitivity towards light revealed their potential as photocleavable molecules. The binding...

  17. Superhydrophobic Copper Surfaces with Anticorrosion Properties Fabricated by Solventless CVD Methods.

    Science.gov (United States)

    Vilaró, Ignasi; Yagüe, Jose L; Borrós, Salvador

    2017-01-11

    Due to continuous miniaturization and increasing number of electrical components in electronics, copper interconnections have become critical for the design of 3D integrated circuits. However, corrosion attack on the copper metal can affect the electronic performance of the material. Superhydrophobic coatings are a commonly used strategy to prevent this undesired effect. In this work, a solventless two-steps process was developed to fabricate superhydrophobic copper surfaces using chemical vapor deposition (CVD) methods. The superhydrophobic state was achieved through the design of a hierarchical structure, combining micro-/nanoscale domains. In the first step, O 2 - and Ar-plasma etchings were performed on the copper substrate to generate microroughness. Afterward, a conformal copolymer, 1H,1H,2H,2H-perfluorodecyl acrylate-ethylene glycol diacrylate [p(PFDA-co-EGDA)], was deposited on top of the metal via initiated CVD (iCVD) to lower the surface energy of the surface. The copolymer topography exhibited a very characteristic and unique nanoworm-like structure. The combination of the nanofeatures of the polymer with the microroughness of the copper led to achievement of the superhydrophobic state. AFM, SEM, and XPS were used to characterize the evolution in topography and chemical composition during the CVD processes. The modified copper showed water contact angles as high as 163° and hysteresis as low as 1°. The coating withstood exposure to aggressive media for extended periods of time. Tafel analysis was used to compare the corrosion rates between bare and modified copper. Results indicated that iCVD-coated copper corrodes 3 orders of magnitude slower than untreated copper. The surface modification process yielded repeatable and robust superhydrophobic coatings with remarkable anticorrosion properties.

  18. Electrochemical in-situ impregnation of wood using a copper nail as source for copper

    DEFF Research Database (Denmark)

    Ottosen, Lisbeth M.; Block, Thomas; Nymark, Morten

    2011-01-01

    A new method for copper impregnation of wood in structures was suggested and tested in laboratory scale with specimen of new pine sapwood. A copper nail and a steel screw were placed in the wood, and an electric direct current field was applied, so the copper nail was anode and the screw...... was cathode. At the anode, copper ions were generated. The copper ions were transported into the wood by electromigration (movement of ions in an applied electric field) towards the cathode, and a volume between the two electrodes was thereby impregnated. Copper also moved to a lesser degree in the opposite...

  19. Ammonia leaching of copper smelter dust and precipitation as copper sulphide

    International Nuclear Information System (INIS)

    Morales, A.; Hevia, J. F.; Cifuentes, G.

    2009-01-01

    The effect of ammonia on the leaching of copper smelter dust and copper precipitation from these solutions as sulphide using sulfur and sulfur dioxide was studied. The precipitation was done in ammoniacal media because this solution produced more satisfactory results at room temperature that a sulphuric media. A solid was precipitated containing 60 % of copper of the dust smelter. The other waste generated contained around 80 % of the arsenic of the original copper smelter dust. Based on the preliminary results obtained in this work it will propose a procedure for the recovery of copper as sulphide from copper smelter dust with parallel confinement of arsenic. (Author) 14 refs.

  20. Experimental Investigation on the Mechanism of Chelation-Assisted, Copper(II) Acetate-Accelerated Azide-Alkyne Cycloaddition

    Science.gov (United States)

    Kuang, Gui-Chao; Guha, Pampa M.; Brotherton, Wendy S.; Simmons, J. Tyler; Stankee, Lisa A.; Nguyen, Brian T.; Clark, Ronald J.; Zhu, Lei

    2011-01-01

    A mechanistic model is formulated to account for the high reactivity of chelating azides (organic azides capable of chelation-assisted metal coordination at the alkylated azido nitrogen position) and copper(II) acetate (Cu(OAc)2) in copper(II)-mediated azide-alkyne cycloaddition (AAC) reactions. Fluorescence and 1H NMR assays are developed for monitoring the reaction progress in two different solvents – methanol and acetonitrile. Solvent kinetic isotopic effect and pre-mixing experiments give credence to the proposed different induction reactions for converting copper(II) to catalytic copper(I) species in methanol (methanol oxidation) and acetonitrile (alkyne oxidative homocoupling), respectively. The kinetic orders of individual components in a chelation-assisted, copper(II)-accelerated AAC reaction are determined in both methanol and acetonitrile. Key conclusions resulting from the kinetic studies include (1) the interaction between copper ion (either in +1 or +2 oxidation state) and a chelating azide occurs in a fast, pre-equilibrium step prior to the formation of the in-cycle copper(I)-acetylide, (2) alkyne deprotonation is involved in several kinetically significant steps, and (3) consistent with prior experimental and computational results by other groups, two copper centers are involved in the catalysis. The X-ray crystal structures of chelating azides with Cu(OAc)2 suggest a mechanistic synergy between alkyne oxidative homocoupling and copper(II)-accelerated AAC reactions, in which both a bimetallic catalytic pathway and a base are involved. The different roles of the two copper centers (a Lewis acid to enhance the electrophilicity of the azido group and a two-electron reducing agent in oxidative metallacycle formation, respectively) in the proposed catalytic cycle suggest that a mixed valency (+2 and +1) dinuclear copper species be a highly efficient catalyst. This proposition is supported by the higher activity of the partially reduced Cu(OAc)2 in

  1. Characterisation of the interactions between substrate, copper(II) complex and DNA and their role in rate acceleration in DNA-based asymmetric catalysis.

    Science.gov (United States)

    Draksharapu, Apparao; Boersma, Arnold J; Browne, Wesley R; Roelfes, Gerard

    2015-02-28

    Interactions of the azachalcone derived substrate Aza with copper(II) complexes in the presence and absence of st-DNA were studied in detail by UV/Vis absorption, EPR and Raman and (UV and vis) resonance Raman spectroscopies. The binding of Aza to the Lewis acidic copper(II) complexes, which results in activation of the substrate, was established spectroscopically. It was shown that the binding of Aza differs between Cu(II)dmbpy and Cu(II)terpy, consistent with the observed differences in catalytic asymmetric Diels-Alder reactions with regard to both the rate and enantiomeric preference. Finally, it was shown that DNA has a major beneficial effect on the binding of Aza to the copper(II) complex due to the fact that both bind to the DNA. The result is a high effective molarity of both the copper complexes and the Aza substrate, which leads to a significant increase in binding of Aza to the copper(II) complex. This effect is a key reason for the observed rate acceleration in the catalyzed reactions brought about by the presence of DNA.

  2. High performance 3D printed electronics using electroless plated copper

    Directory of Open Access Journals (Sweden)

    Jin Rong Jian

    2017-03-01

    Full Text Available This paper presents design and performance validation of 3D printed electronic components, 3D toroidal air-core inductors, fabricated by multi-material based Fused Deposition Modelling (FDM 3D printing technology and electroless copper plating. Designs of toroidal inductor is investigated with different core shapes and winding numbers; circular and half-circular cores with 10 and 13 turns of windings. Electroless plated copper thin film ensures 3D printed toroidal plastic structures to possess inductive behaviors. The inductance is demonstrated reliably with an applied source frequency from 100 kHz to 2 MHz as designs vary. An RL circuit is utilized to test the fabricated inductors’ phase-leading characteristics with corresponding phase angle changes.

  3. Carboranedithiols: building blocks for self-assembled monolayers on copper surfaces.

    Science.gov (United States)

    Baše, Tomáš; Bastl, Zdeněk; Havránek, Vladimír; Macháček, Jan; Langecker, Jens; Malina, Václav

    2012-08-28

    Two different positional isomers of 1,2-dicarba-closo-dodecaboranedithiols, 1,2-(HS)(2)-1,2-C(2)B(10)H(10) (1) and 9,12-(HS)(2)-1,2-C(2)B(10)H(10) (2), have been investigated as cluster building blocks for self-assembled monolayers (SAMs) on copper surfaces. These two isomers represent a convenient system in which the attachment of SH groups at different positions on the skeleton affects their acidic character and thus also determines their reactivity with a copper surface. Isomer 1 exhibited etching of polycrystalline Cu films, and a detailed investigation of the experimental conditions showed that both the acidic character of SH groups and the presence of oxygen at the copper surface play crucial roles in how the surface reaction proceeds: whether toward a self-assembled monolayer or toward copper film etching. We found that each positional isomer requires completely different conditions for the preparation of a SAM on copper surfaces. Optimized conditions for the former isomer required the exposure of a freshly prepared Cu surface to vapor of 1 in vacuum, which avoided the presence of oxygen and moisture. Adsorption from a dichloromethane solution afforded a sparsely covered Cu(0) surface; isomer 1 effectively removes the surface copper(I) oxide, forming a soluble product, but apparently binds only weakly to the clean Cu(0) surface. In contrast, adsorption of the latter, less volatile isomer proceeded better from a dichloromethane solution than from the vapor phase. Isomer 2 was even able to densely cover the copper surface cleaned up by the dichloromethane solution of 1. Both isomers exhibited high capacity to remove oxygen atoms from the surface copper(I) oxide that forms immediately after the exposure of freshly prepared copper films to ambient atmosphere. Isomer 2 showed suppression of Cu film oxidation. A number of methods including X-ray photoelectron spectroscopy (XPS), X-ray Rutherford back scattering (RBS), proton-induced X-ray emission (PIXE) analysis

  4. Spectroscopic studies on the interaction of DNA with the copper complexes of NSAIDs lornoxicam and isoxicam.

    Science.gov (United States)

    Goswami, Sathi; Ray, Suhita; Sarkar, Munna

    2016-12-01

    Non Steroidal Anti-inflammatory Drugs (NSAIDs) form the most common class of anti-inflammatory and analgesic agents. They also show anticancer properties for which they exert their effects by interacting at the protein but not at the genomic level. This is because most NSAIDs are anions at physiological pH, which prohibit their approach to the polyanionic DNA backbone. Complexing NSAIDs with bioactive metal like copper obliterates this disadvantage. Here, copper complexes of two oxicam NSAIDs, Lornoxicam (Lx) and Isoxicam (Isx) have been chosen to study their interaction with calf thymus (ct) DNA and have been synthesized as per reported protocols. UV-vis absorption showed that DNA binding to Cu(II)-Lx complex alters the absorption spectra indicating changes in the electronic environment of the complex, whereas, for Cu(II)-Isx there was only small changes. Hence, UV-vis absorption was used to determine the binding constant, stoichiometry and thermodynamic parameters of Cu(II)-Lx. However, UV-melting studies and CD difference spectra showed that both Cu(II)-Lx and Cu(II)-Isx can interact with the DNA backbone albeit with different binding modes. The probable binding mode was determined by kinetics of EtBr displacement and viscosity measurements. Our results point to an intercalative mode of binding for Cu(II)-Lx and external groove binding for Cu(II)-Isx. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Canine Models for Copper Homeostasis Disorders

    Directory of Open Access Journals (Sweden)

    Xiaoyan Wu

    2016-02-01

    Full Text Available Copper is an essential trace nutrient metal involved in a multitude of cellular processes. Hereditary defects in copper metabolism result in disorders with a severe clinical course such as Wilson disease and Menkes disease. In Wilson disease, copper accumulation leads to liver cirrhosis and neurological impairments. A lack in genotype-phenotype correlation in Wilson disease points toward the influence of environmental factors or modifying genes. In a number of Non-Wilsonian forms of copper metabolism, the underlying genetic defects remain elusive. Several pure bred dog populations are affected with copper-associated hepatitis showing similarities to human copper metabolism disorders. Gene-mapping studies in these populations offer the opportunity to discover new genes involved in copper metabolism. Furthermore, due to the relatively large body size and long life-span of dogs they are excellent models for development of new treatment strategies. One example is the recent use of canine organoids for disease modeling and gene therapy of copper storage disease. This review addresses the opportunities offered by canine genetics for discovery of genes involved in copper metabolism disorders. Further, possibilities for the use of dogs in development of new treatment modalities for copper storage disorders, including gene repair in patient-derived hepatic organoids, are highlighted.

  6. Thermal conductivity of glass copper-composite

    International Nuclear Information System (INIS)

    Kinoshita, Makoto; Terai, Ryohei; Haidai, Haruki

    1980-01-01

    Glass-metal composites are to be one of the answers for promoting thermal conduction in the glassy solids containing high-level radioactive wastes. In order to investigate the effect of metal addition on thermal conductivity of glasses, glass-copper composites were selected, and the conductivities of the composites were measured and discussed in regards to copper content and microstructure. Fully densified composites were successfully prepared by pressure sintering of the powder mixtures of glass and copper at temperatures above the yield points of the constituent glasses if the copper content was not so much. The conductivity was measured by means of a comparative method, in which the thermal gradient of the specimen was compared with that of quartz glass as standard under thermally steady state. Measurements were carried out at around 50 0 C. The thermal conductivity increased with increasing content of copper depending on the kind of copper powder used. The conductivities of the composites of the same copper content differed considerably each another. Fine copper powder was effective on increasing conductivity, and the conductivity became about threefold of that of glass by mixing the fine copper powder about 10 vol%. For the composites containing the fine copper powder less than 5 vol%, the conductivity obeyed so-called logarithmic rule, one of the mixture rules of conductivity, whereas for composites containing more than 5 vol%, the conductivity remarkably increased apart from the rule. This fact suggests that copper becomes continuous in the composite when the copper content increased beyond 5 vol%. For the composites containing coarse copper powder, the conductivity was increased not significantly, and obeyed an equation derived from the model in which conductive material dispersed in less conductive one. (author)

  7. Evaluation of copper resistant bacteria from vineyard soils and mining waste for copper biosorption.

    Science.gov (United States)

    Andreazza, R; Pieniz, S; Okeke, B C; Camargo, F A O

    2011-01-01

    Vineyard soils are frequently polluted with high concentrations of copper due application of copper sulfate in order to control fungal diseases. Bioremediation is an efficient process for the treatment of contaminated sites. Efficient copper sorption bacteria can be used for bioremoval of copper from contaminated sites. In this study, a total of 106 copper resistant bacteria were examined for resistance to copper toxicity and biosorption of copper. Eighty isolates (45 from vineyard Mollisol, 35 from Inceptisol) were obtained from EMBRAPA (Empresa Brasileira de Pesquisa Agropecuária) experimental station, Bento Gonçalves, RS, Brazil (29°09'53.92″S and 51°31'39.40″W) and 26 were obtained from copper mining waste from Caçapava do Sul, RS, Brazil (30°29'43.48″S and 53'32'37.87W). Based on resistance to copper toxicity and biosorption, 15 isolates were identified by 16S rRNA gene sequencing. Maximal copper resistance and biosorption at high copper concentration were observed with isolate N2 which removed 80 mg L(-1) in 24 h. Contrarily isolate N11 (Bacillus pumilus) displayed the highest specific copper biosorption (121.82 mg/L/OD unit in 24 h). GenBank MEGABLAST analysis revealed that isolate N2 is 99% similar to Staphylococcus pasteuri. Results indicate that several of our isolates have potential use for bioremediation treatment of vineyards soils and mining waste contaminated with high copper concentration.

  8. LEP Radio Frequency Copper Cavity

    CERN Multimedia

    The pulse of a particle accelerator. 128 of these radio frequency cavities were positioned around CERN's 27-kilometre LEP ring to accelerate electrons and positrons. The acceleration was produced by microwave electric oscillations at 352 MHz. The electrons and positrons were grouped into bunches, like beads on a string, and the copper sphere at the top stored the microwave energy between the passage of individual bunches. This made for valuable energy savings as it reduced the heat generated in the cavity.

  9. Ecology of subtropical, shallow water environments: chemistry of copper and chlorine introduced into marine systems during energy production

    International Nuclear Information System (INIS)

    1980-01-01

    During the last three contract years, we have been involved in the study of the chemistry of the copper binding compounds occurring in coastal seawater. Initially our efforts were oriented towards the study of the complexing capacity of waters collected at various locations in the Miami, Florida area. Our study then shifted towards the concentration and the elucidation of these chelators

  10. 113Cd-NMR investigation of a cadmium-substituted copper, zinc-containing superoxide dismutase from yeast

    DEFF Research Database (Denmark)

    Kofod, Pauli; Bauer, Rogert; Danielsen, Eva

    1991-01-01

    113Cd nuclear magnetic resonance spectroscopy has been used to investigate the metal binding sites of cadmium-substituted copper,zinc-containing superoxide dismutase from baker's yeast. NMR signals were obtained for 113Cd(II) at the Cu site as well as for 113Cd(II) at the Zn site. The two subunits...

  11. Molecular genetics and transport analysis of the copper-resistance determinant (pco) from Escherichia coli plasmid pRJ1004.

    Science.gov (United States)

    Brown, N L; Barrett, S R; Camakaris, J; Lee, B T; Rouch, D A

    1995-09-01

    The copper-resistance determinant (pco) of Escherichia coli plasmid pRJ1004 was cloned and sequenced. Tn1000 transposon mutagenesis identified four complementation groups, mutations in any of which eliminated copper resistance. DNA sequence analysis showed that the four complementation groups contained six open reading frames, designated pco-ABCDRS. The protein product sequences derived from the nucleotide sequence show close homology between this copper-resistance system and the cop system of a plasmid pPT23D of Pseudomonas syringae pv. tomato. The PcoR and PcoS protein sequences show homology to the family of two-component sensor/responder phosphokinase regulatory systems. A seventh reading frame (pcoE) was identified from DNA sequence data, and lies downstream of a copper-regulated promoter. Transport assays with 64Cu(II) showed that the resistant cells containing the plasmid had reduced copper accumulation during the log phase of growth, while increased accumulation had previously been observed during stationary phase. Chromosomal mutants defective in cellular copper management were obtained and characterized. In two of these mutants pco resistance was rendered totally inactive, whilst in another two mutants pco complemented the defective genes. These data indicate that plasmid-borne copper resistance in E. coli is linked with chromosomal systems for copper management.

  12. NMR backbone resonance assignments of the N, P domains of CopA, a copper-transporting ATPase, in the apo and ligand bound states.

    Science.gov (United States)

    Meng, Dan; Bruschweiler-Li, Lei; Zhang, Fengli; Brüschweiler, Rafael

    2015-04-01

    Copper-transporting ATPase, a member of P-type ATPase family, plays a key role in the homeostasis of cellular copper levels. Here, the backbone assignments of the directly connected N and P domains (292 residues, 31 kDa) of Cu-transporting ATPase in the ligand free and the AMPPCP-bound states are reported in solution. The NMR assignments pave the way for binding and dynamics studies of this enzyme to better understand its function.

  13. Effect of Copper Treatment on the Composition and Function of the Bacterial Community in the Sponge Haliclona cymaeformis

    KAUST Repository

    Tian, R.-M.

    2014-11-04

    Marine sponges are the most primitive metazoan and host symbiotic microorganisms. They are crucial components of the marine ecological system and play an essential role in pelagic processes. Copper pollution is currently a widespread problem and poses a threat to marine organisms. Here, we examined the effects