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PubMed2005

Effects of dissolved organic carbon on copper toxicity: implications for saltwater copper criteria.

During the past three decades, significant advances have been made in understanding how environmental factors modify the bioavailability and the toxicity of metals such as copper in aquatic environments. Several of these advances have led to the development of guidelines to indirectly account for modifying factors, adjustment of criteria on a site-specific basis, and direct changes to the U.S. Environmental Protection Agency (U.S. EPA) freshwater quality criteria. To date, most of this effort has focused on freshwater systems, although similar modifying factors exist in marine environments as well. This paper focuses on one such modifying factor, dissolved organic carbon (DOC), and describes a method to aid in risk assessments or to refine the saltwater copper criteria on a site-specific basis. The relationship between DOC and toxicity of copper to the most sensitive saltwater genus in the U.S. EPA criteria database, Mytilus, is extensively analyzed. Dissolved copper 50% effective concentrations (EC50s) are highly correlated (r2 = 0.71, n=54, p < 0.001) across a wide range of sample DOC concentrations (0.3-10 mg carbon [C]/L) and are explained by the equation EC50 = 11.53DOC(0.54). Two equations based on DOC are proposed for consideration as a means for deriving site-specific final chronic criteria (FCC) and final acute criteria (FAC) for copper in marine and estuarine environments (Copper FCC(DOC) = 3.71DOC(0.54) and Copper FAC(DOC) = 5.843DOC(0.54).

Animals↗

PubMed1983

Effect of copper or insulin in diabetic copper-deficient rats.

The effects of copper and insulin on lipogenesis and glucose tolerance were studied using diabetic, copper-deficient rats. Diabetes was induced by intraperitoneal injection of 50 mg streptozotocin/kg body weight to rats fed a sucrose-copper deficient diet for 7 weeks. Five days later the rats were injected intraperitoneally with [14C]glucose with either saline, insulin, copper, or copper plus insulin. The disappearance of serum [14C]glucose at 30, 60, and 120 min postinjection and the incorporation of [14C]glucose into lipid of epididymal fat 2 hr after administration were determined. The combined effect of copper and insulin significantly decreased peak blood glucose at 30 min and increased the incorporation of [14C]glucose into lipid in the epididymal fat pad when compared to either copper or insulin alone. The enhancement of glucose utilization may be due to a formation of a more stable complex which will increase insulin binding and/or decrease its degradation.

Adipose Tissue↗

PubMed2001

A comparison of the kinetics of low-density lipoprotein oxidation induced by copper or by gamma-rays: influence of radiation dose-rate and copper concentration.

The oxidation of low-density lipoproteins is the first step in the complex process leading to atherosclerosis. The aim of our study was to compare the kinetics of low density lipoprotein oxidation induced by copper ions or by oxygen free radicals generated by 60Co gamma-rays. The effects of copper concentration and irradiation dose-rate on LDL peroxidation kinetics were also studied. The oxidation of LDL was followed by the measurement of conjugated diene, hydroperoxides, and thiobarbituric acid reactive substance formation as well as alpha-tocopherol disappearance. In the case of gamma irradiation, the lag-phase before the onset of lipid peroxidation was inversely correlated to the radiation dose-rate. The radiation chemical rates (nu) increased with increasing dose-rate. Copper-induced LDL peroxidation followed two kinetic patterns: a slow kinetic for copper concentrations between 5-20 microM, and a fast kinetic for a copper concentration of 40 microM. The concentration-dependent oxidation kinetics suggest the existence of a saturable copper binding site on apo-B. When compared with gamma-rays, copper ions act as drastic and powerful oxidants only at higher concentrations (> or = 40 microM).

Adult↗

PubMed1990

A review of the biochemical roles, toxicity and interactions of zinc, copper and iron: II. Copper.

Copper is an essential nutrient for living matter. Through its cuproenzymes, copper displays a variety of metabolic functions. Atomic absorption spectrophotometry, radioisotope studies and establishment of cell and molecular biology have provided the necessary tools to study copper absorption, metabolism, physiology and biochemistry. The vital role of metallothionein in copper homeostasis is examined. Ceruloplasmin represents the molecular link between copper and iron metabolism. The genetic predisposition of copper toxicity has been attributed to the cause of Wilson's disease in humans. The interrelationships between copper and other dietary factors is addressed.

Animals↗

PubMed1990

Effect of ostertagiasis on copper status in sheep: a study involving use of copper oxide wire particles.

Lambs infected with Ostertagia circumcincta larvae and uninfected controls were either doses with 5 g copper oxide wire particles (COWP) or remained undosed. The change in abomasal pH was monitored from duodenal digesta and that in liver copper concentration from initial liver biopsy samples and liver obtained at necropsy after 22 days. Infection increased the pH of digesta from 2.5 to 4.5. The change in liver copper content in sheep not treated with COWP was +6.1 mg (12.6 per cent) and -6.8 mg (13.8 per cent) in control and infected sheep, respectively. Significantly greater amounts of COWP were recovered from the abomasa of infected than from control animals (3.6 +/- 0.23 and 1.6 +/- 0.55 g, respectively) and hepatic uptake of copper from COWP was 0.7 and 1.8 per cent of the dose, respectively. There were significant relationships between the pH of duodenal contents and COWP retained, soluble copper concentration in duodenal digesta and hepatic uptake of copper. It was concluded that, through causing an increase in pH in abomasal and duodenal digesta, gastrointestinal nematodes interfere with copper metabolism.

Abomasum↗

PubMedDate not supplied

Mineralization procedure for determination of copper in aerosols using photometric method based on copper-BPKQH complex.

A mineralization procedure is proposed for copper aerosols in which samples are mineralized by wet-ashing with HNO3 + HCIO4 mixture. Copper content is determined by a photometric method based on formation of a complex between copper and benzyl 2-pyridyl ketone 2-quinolylhydrazone (BPKQH). The influence of pH, ethanol content, and reagent concentration is studied. Copper determination at pH = 7.3, in the range 0.05 to 3 ppm is proposed. Mineralization with HNO3 is carried out in different conditions of evaporation (with or without dryness) and manipulation. Analysis of variance by the (ANOVA) single factor method shows that digestion conditions significantly increase the variability of results. Repeatability assays suggest that nitric acid alone gives low precision. Recovery assays reveal that the HNO3 digestion process causes copper loss by volatilization. Mineralization with HNO3 + HCIO4 is optimized on the basis of the accuracy and precision obtained. The ANOVA method suggests that mineralization conditions significantly increase total variability of results and also that results of the photometric method are not significantly different from those of the AAS method. The optimum mineralization procedure gave an RSD of 0.63% and a copper recovery of 98.4%. The combined digestion and quantification method was applied to determination of copper in aerosol samples obtained during leaf spraying operations of olive trees in the field.

Aerosols↗

PubMed1987

[Experimental study on rat hepatic injury by copper--effect of copper overload on the cholestatic liver induced by bile duct ligation].

In the cases of protracted obstructive jaundice, it is reported that there was a positive correlation between the hepatic copper concentration and the severity of destruction of the bile ducts. The author produced the model of obstructive jaundice in rats by common bile duct ligation and investigated whether additional copper overload can cause injury on the liver. The simple ligating procedure induced a significantly increased level of the copper concentration (p less than 0.001). The copper concentration of the group with the additional copper overload showed about an eighteen-fold increase in comparison with the group of the only ligation (p less than 0.005). Histologically, the group with the overload alone exhibited no significant finding. The groups with the ligation showed bile duct proliferation with subsequent fibrosis around portal areas (pericholangiolar fibrosis); however, the fibrosis in the group with an additional overload was more prominent than that without an additional overload. By the orcein stain, the positive granules in the group with the ligation alone were preferentially present in the liver cells around the proliferated bile ducts. The group with the additional overload exhibited diffuse and more pronounced staining. Ultrastructurally, the liver cells in the group with the additional overload contained lysosomes with electron-dense material, some of which showed a feature consistent with focal interruption of their membranes. By X-ray microanalysis, these lysosomes were revealed to include copper as well as sulfur. The sulfur was considered to represent copper-binding protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1979

Copper, zinc and iron levels in the cerebrospinal fluid of copper poisoned sheep.

Copper, zinc and iron levels were measured in cerebrospinal fluid (CSF) of normal and copper poisoned sheep. Copper values were within the range recorded for humans but zinc levels were six to 20 times and iron levels were 20 to 30 times higher than values reported for humans. The amount of copper, zinc and iron in the CSF did not increase in sheep dosed with copper and hence it is unlikely that the level of copper in the CSF is related to the changes in the nervous system that have been reported in copper poisoned sheep.

Animals↗

PubMed1984

Electron probe X-ray analysis on human hepatocellular lysosomes with copper deposits: copper binding to a thiol-protein in lysosomes.

Livers of eight patients with chronic liver diseases were investigated by energy dispersive x-ray analysis. First, three kinds of preparations (osmium-Epon sections, glutaraldehyde-frozen sections, and unfixed-frozen sections) were compared for element detectability at a subcellular level. The glutaraldehyde-frozen sections were satisfactory as far as copper, sulfur, and phosphorus were concerned. Five patients (one patient with Wilson's disease, one chronic cholestasis, one chronic hepatitis, and two asymptomatic primary biliary cirrhosis) yielded x-ray images of copper and sulfur consistent with hepatocellular lysosomes. Second, the glutaraldehyde-frozen sections were utilized for a study of copper deposits in the patients' livers. There was a significant correlation between copper and sulfur contents in the lysosomes of all patients studied but no correlation in the remainder of the cytoplasm. Zinc was not detected in the lysosomes. Whatever the content of copper in the lysosomes, the ratio of delta copper to phosphorus (weight/weight) to delta sulfur to phosphorus was 0.60. These data indicate that most lysosomal copper binds to a thiol protein, probably metallothionein, in the liver.

Adolescent↗

PubMed1984

Performance and tissue copper concentrations of control and Ascaris suum-infected pigs fed excess dietary copper.

Ninety-eight crossbred growing-finishing swine were used in 2 experiments to investigate the interaction between naturally occurring Ascaris suum infections and excess copper ingestion. In both experiments, pigs were fed a 14% crude protein basal diet or the basal diet + 250 ppm copper. These 2 dietary groups were subsequently divided into 2 additional treatment groups (A. suum-infected or uninfected) based on worm recovery from the intestine or from fecal egg counts. Excess dietary copper improved pig performance slightly, but it dramatically increased liver, kidney and lung copper levels. The A. suum infection did not affect pig performance, but it tended (not significantly) to reduce tissue copper levels. Serum copper was not affected by dietary copper or by A. suum infection.

Animals↗

PubMed1977

Cytochemical methods for copper. Semiquantitative screening procedure for identification of abnormal copper levels in liver.

Three previously described histochemical methods for the localization of copper were examined for applicability in the semiquantitative evaluation copper levels in human tissue. Liver tissue obtained at autopsy was stained using dimethylaminobenzylidene rhodanine, rubeanic acid, and diethyldithiocarbamate procedures. The effects of method and time of fixation, staining, incubation time, and variations in procedures were evaluated. Copper levels in tissues examined were determined using atomic absorption spectroscopy. Each staining method was evaluated for sensitivity, reproducibility, and linearity. The rhodanine method was found to produce the most reproducible results, and a linear relationship between microscopical evaluation of the stain and actual tissue copper levels was observed. It was concluded that the rhodanine copper method is applicable for the semi-quantitative evaluation of tissue copper and provides a satisfactory screening method for the identification of abnormal tissue copper levels.

Copper↗

PubMed1982

Changes in the liver copper content of Welsh mountain sheep after the injection of organic compounds of copper.

Subcutaneous injections of copper methionate, copper calcium edetate and copper oxyquinoline sulphonate were given to Welsh ewes in doses which provided amounts of copper ranging from 0 . 3 to 4 . 0 mg/kg bodyweight. The effect on the liver copper content was studied by analysing serial biopsy samples. The results suggest that a safer use of copper calcium edetate and a more efficacious use of copper oxyquinoline sulphate might be achieved by a reduction in the recommended dose of the former and an increase of the latter.

Animals↗

PubMed2000

Formation of copper oxychloride and reactive oxygen species as causes of uterine injury during copper oxidation of Cu-IUD.

The lining of the uterus and cervix might be injured by a variety of oxidation products of Cu in a Cu-IUD, including cuprous ions, dissolved and precipitated cupric ions, and reactive oxygen species such as superoxide radicals, hydrogen peroxide, and hydroxyl radicals. In this study, the human amnious WISH cell line was employed as a model of uterine cells in the presence of copper. The cell viability was decreased by elemental copper, which was alleviated up to 70% by the addition of catalase. The addition of copper oxychloride caused cell death in a dose-dependent manner. Hydroxyl radicals in the presence of copper were determined by the formation of malondialdehyde. Soluble cuprous chloride complexes are formed in the uterus by slowly entering oxygen. The complexes are partly oxidized to insoluble copper oxychloride. which damages the endometrium. Unoxidized cuprous ions migrate to the oxygen-rich cervix and are oxidized to copper oxychloride, causing cervix damage.

Catalase↗

PubMed2006

Structure of human Wilson protein domains 5 and 6 and their interplay with domain 4 and the copper chaperone HAH1 in copper uptake.

Human Wilson protein is a copper-transporting ATPase located in the secretory pathway possessing six N-terminal metal-binding domains. Here we focus on the function of the metal-binding domains closest to the vesicular portion of the copper pump, i.e., domain 4 (WLN4), and a construct of domains 5 and 6 (WLN5-6). For comparison purposes, some experiments were also performed with domain 2 (WLN2). The solution structure of apoWLN5-6 consists of two ferredoxin folds connected by a short linker, and (15)N relaxation rate measurements show that it behaves as a unit in solution. An NMR titration of apoWLN5-6 with the metallochaperone Cu(I)HAH1 reveals no complex formation and no copper exchange between the two proteins, whereas titration of Cu(I)HAH1 with WLN4 shows the formation of an adduct that is in fast exchange on the NMR time scale with the isolated protein species as confirmed by (15)N relaxation data. A similar interaction is also observed between Cu(I)HAH1 and WLN2; however, the relative amount of the adduct in the protein mixture is lower. An NMR titration of apoWLN5-6 with Cu(I)WLN4 shows copper transfer, first to WLN6 then to WLN5, without the formation of an adduct. Therefore, we suggest that WLN4 and WLN2 are two acceptors of Cu(I) from HAH1, which then somehow route copper to WLN5-6, before the ATP-driven transport of copper across the vesicular membrane.

Adenosine Triphosphatases↗

PubMed2002

Syntheses, crystal structures, and physical properties of dinuclear copper(I) and tetranuclear mixed-valence copper(I,II) complexes with hydroxylated bipyridyl-like ligands.

Four copper complexes with hydroxylated bipyridyl-like ligands, namely [Cu(2)(ophen)(2)] (1), [Cu(4)(ophen)(4)(tp)] (2), [Cu(4)(obpy)(4)(tp)] (3), and [Cu(4)(obpy)(4)(dpdc)].2H(2)O (4), (Hophen=2-hydroxy-1,10-phenanthroline, Hobpy=6-hydroxy-2,2'-bipyridine, tp=terephthalate, dpdc=diphenyl-4,4'-dicarboxylate) have been synthesized hydrothermally. X-ray single-crystal structural analyses of these complexes reveal that 1,10-phenanthroline (phen) or 2,2'-bipyridine (bpy) ligands are hydroxylated into ophen or obpy during the reaction, which provides structural evidence for the long-time argued Gillard mechanism. The dinuclear copper(I) complex 1 has three supramolecular isomers in the solid state, in which short copper-copper distances (2.66-2.68 A) indicate weak metal-metal bonding interactions. Each of the mixed-valence copper(i,ii) complexes 2-4 consists of a pair of [Cu(2)(ophen)(2)](+) or [Cu(2)(obpy)(2)](+) fragments bridged by a dicarboxylate ligand into a neutral tetranuclear dumbbell structure. Dinuclear 1 is an intermediate in the formation of 2 and can be converted into 2 in the presence of additional copper(II) salt and tp ligands under hydrothermal conditions. In addition to the ophen-centered pi-->pi* excited-state emission, 1 shows strong emissions at ambient temperature, which may be tentatively assigned as an admixture of copper-centered d-->s,p and MLCT excited states.

Journal Article↗

PubMed1987

Kinetic studies of the copper nitrite reductase from Achromobacter cycloclastes and its interaction with a blue copper protein.

Transient state, burst and steady state kinetics of reactions of the blue copper nitrite reductase (NIR) and blue copper protein from Achromobacter cycloclastes are investigated. The two copper-containing species are reacted with each other and where possible with dithionite, ascorbate and nitrite. Both copper proteins are fully reduced by dithionite with both S2O4(2-) and SO2-. species active. NIR is only partially reduced by ascorbate in an unusual biphasic reaction consistent with complete reduction of type-one copper followed by partial reduction of type-two copper. The rate of reduction of the type-one copper is accelerated using phenazine methosulfate as mediator. Nitrite can oxidize dithionite-reduced NIR but cannot reduce oxidized NIR. Rate constants were determined for all observed reactions.

Alcaligenes↗

PubMed2003

Copper-selenium interactions: influence of alkane spacer and halide anion in the synthesis of unusual polynuclear copper(I) complexes with bis(diphenylselenophosphinyl)alkanes.

The reactions of copper(I) halides with bis(diphenylselenophosphinyl)alkanes, namely Ph(2)P(Se)-(CH(2))(n)-P(Se)Ph(2) [n = 1-4], in acetonitrile are described. The ligand 1,3-bis(diphenylselenophosphinyl)propane [dppp-Se,Se] with copper(I) bromide and copper(I) iodide formed two unusual infinite coordination polymers, namely [Cu(2)Br(2)(mu(2)-dppp-Se-Se)(2)](n), 1, and [Cu(3)I(3)(mu(2)-dppp-Se,Se)(2)](n), 2. Selenium bridged dinuclear complexes, [Cu(2)Br(2)((mu(3)-dppm-Se,Se)(2)], 3, and [Cu(2)I(2)(dppm-Se,Se)(2)], 4, were formed using 1,1-bis(diphenylselenophosphinyl)methane [dppm-Se,Se]. Similarly, 1,2-bis(diphenylselenophosphinyl)ethane [dppe-Se,Se] and 1,4-bis(diphenylselenophosphinyl)butane [dppb-Se,Se] formed complexes, Cu(2)Br(2)(dppe-Se,Se)(2), 5, and Cu(2)I(2)(dppb-Se,Se), 6. These have been characterized with the help of analytical data, infrared spectroscopy, and, for compounds 1-3, X-ray crystallography. Compound 2, [Cu(3)I(3(dppp-Se,Se)(2)](n), has two dppp-Se,Se molecules coordinating to two copper(I) atoms of the dinuclear Cu(mu-I)(2)Cu core in unidentate fashion, with two pendant Ph(2)P(Se)- moieties in trans orientation, and one of these groups is coordinated to another copper(I) iodide moiety, thus forming the repeat unit (A), -CuI(mu-dppp-Se,Se)Cu(mu-I)(2)Cu(mu-dppp-Se,Se)-. This repeat unit (A) combined with another unit, and this process continued and finally formed the infinite polymer 2. In this polymer, the mononuclear CuISe(2) and dinuclear Cu(2)(mu-I)(2)Se(2) cores have distorted trigonal planar geometries around Cu centers. The Cu(2)...Cu(2)* separation of 2.643(1) A is less than twice the van der Waals radius of Cu, 2.80 A. The structure of polymer 1 is similar to that of 2, except that it has only mononuclear trigonal planar CuBrSe(2) units bridged by Se atoms of dppp-Se,Se ligand, and the repeat unit is -CuBr(mu(2)-dppp-Se,Se)CuBr(mu(2)(-)dppp-Se,Se)-. The formation of zigzag one-dimensional copper(I) coordination polymers (1 and 2), with trigonal planar copper(I) centers, provides the first examples of this type in tertiary phosphine chalcogenide chemistry. In contrast, the decrease in methylene chain length, from -(CH(2))(3)- to -(CH(2))-, resulted in chelation by the dppm-Se,Se ligand, forming CuBr(dppm-Se,Se), which dimerized via Se donor atoms and formed [Cu(2)Br(2)(mu(3)-dppm-Se,Se)(2)], 3. It has a relatively less common central kernel, Cu(mu-Se)(2)Cu, and each Cu atom is further bonded to one terminal Br and one Se atoms, and the geometry around each Cu center is distorted tetrahedral (bond angles, ca. 101-121 degrees).

Journal Article↗

PubMed2000

Helical-chain copper(II) complexes and a cyclic tetranuclear copper(II) complex with single syn-anti carboxylate bridges and ferromagnetic exchange interactions.

Tridentate Schiff-base carboxylate-containing ligands, derived from the condensation of 2-imidazolecarboxaldehyde with the amino acids beta-alanine (H2L1) and 2-aminobenzoic acid (H2L5) and the condensation of 2-pyridinecarboxaldehyde with beta-alanine (HL2), D,L-3-aminobutyric acid (HL3), and 4-aminobutyric acid (HL4), react with copper(II) perchlorate to give rise to the helical-chain complexes [[Cu(mu-HL1)(H2O)](ClO4)]n (1), [[Cu(mu-L2)(H2O)](ClO4).2H2O]n (2), and [[Cu(mu-L3)(H2O)](ClO4).2H2O]n (3), the tetranuclear complex [[Cu(mu-L4)(H2O)](ClO4)]4 (4), and the mononuclear complex [Cu(HL5)(H2O)](ClO4).1/2H2O (5). The reaction of copper(II) chloride with H2L1 leads not to a syn-anti carboxylate-bridged compound but to the chloride-bridged dinuclear complex [Cu(HL1)(mu-Cl)]2 (6). The structures of these complexes have been solved by X-ray crystallography. In complexes 1-4, roughly square-pyramidal copper(II) ions are sequentially bridged by syn-anti carboxylate groups. Copper(II) ions exhibit CuN2O3 coordination environments with the three donor atoms of the ligand and one oxygen atom belonging to the carboxylate group of an adjacent molecule occupying the basal positions and an oxygen atom (from a water molecule in the case of compounds 1-3 and from a perchlorate anion in 4) coordinated in the apical position. Therefore, carboxylate groups are mutually cis oriented and each syn-anti carboxylate group bridges two copper(II) ions in basal-basal positions with Cu...Cu distances ranging from 4.541 A for 4 to 5.186 A for 2. In complex 5, the water molecule occupies an equatorial position in the distorted octahedral environment of the copper(II) ion and the Cu-O carboxylate distances in axial positions are very large (>2.78 A). Therefore, this complex can be considered as mononuclear. Complex 6 exhibits a dinuclear parallel planar structure with Ci symmetry. Copper(II) ions display a square-pyramidal coordination geometry (tau = 0.06) for the N2OCl2 donor set, where the basal coordination sites are occupied by one of the bridging chlorine atoms and the three donor atoms of the tridentate ligand and the apical site is occupied by the remaining bridging chlorine atom. Magnetic susceptibility measurements indicate that complexes 1-4 exhibit weak ferromagnetic interactions whereas a weak antiferromagnetic coupling has been established for 6. The magnetic behavior can be satisfactorily explained on the basis of the structural data for these and related complexes.

Journal Article↗