Cu In Tissues Research Articles

Role of myo-inositol supplementation against toxicity of excessive dietary copper in Pacific white shrimp Litopenaeus vannamei

Raw materials for making dried shrimp (a type of foodstuff) are mostly from farmed shrimp and preliminary findings indicated that head copper (Cu) concentrations in some commercial dried shrimp products exceeded the safe limit specified in pollution-free aquatic products (50 mg/kg), which may influence food safety. Therefore, a 63-day feeding trial was conducted to explore effects of dietary Cu concentrations on accumulation of Cu in tissues, growth performance, immune response and antioxidant status of Pacific white shrimp (Litopenaeus vannamei). Moderating effect of myo-inositol (MI, adding 200 mg/kg diet) on the adverse impacts caused by excessive dietary Cu was also investigated. 600 shrimp (initial weight: 0.89 ± 0.00 g) were divided into five groups: 37.08 mg Cu/kg diet group (control group), 62.57 mg Cu/kg diet group, 125.99 mg Cu/kg diet group, 63.41 mg Cu/kg diet group (supplemented with MI) and 119.19 mg Cu/kg diet group (supplemented with MI). The results showed that dietary Cu concentrations increased from 37.08 to over 62.57 mg/kg, hepatopancreas Cu concentrations raised from 29.04 to 233.43–263.65 mg/kg, and muscle Cu concentrations only increased from 6.22 to 6.99–8.39 mg/kg. Report to control group, excessive Cu concentration (125.99 mg/kg) didn’t significantly affect growth performance, but it notably reduced whole body lipid content and immune response, induced oxidative stress and damaged the hepatopancreas structure, which was ameliorated by MI supplementation. The results suggested that consuming shrimp head and its processed products weren’t recommended. Cu concentrations of commercial feeds for Pacific white shrimp should be controlled below 62.57 mg/kg. Additionally, MI supplementation mitigated the negative impacts induced by excessive dietary Cu.

The Function of ATPase Copper Transporter ATP7B in Intestine

Wilson disease is a disorder of copper (Cu) misbalance caused by mutations in ATP7B. ATP7B is highly expressed in the liver-the major site of Cu accumulation in patients with Wilson disease. The intestine also expresses ATP7B, but little is known about the contribution of intestinal ATP7B to normal intestinal copper homeostasis or to Wilson disease manifestations. We characterized the role of ATP7B in mouse intestinal organoids and tissues. We collected intestinal tissues from ATP7B-knockout (Atp7b-/-) and control mice, and established 3-dimensional enteroids. Immunohistochemistry and x-ray fluorescence were used to characterize the distribution of ATP7B and Cu in tissues. Electron microscopy, histologic analyses, and immunoblotting were used to determine the effects of ATP7B loss. Enteroids derived from control and ATP7B-knockout mice were incubated with excess Cu or with Cu-chelating reagents; effects on cell fat content and ATP7B levels and localization were determined by fluorescent confocal microscopy. ATP7B maintains a Cu gradient along the duodenal crypt-villus axis and buffers Cu levels in the cytosol of enterocytes. These functions are mediated by rapid Cu-dependent enlargement of ATP7B-containing vesicles and increased levels of ATP7B. Intestines of Atp7b-/- mice had reduced Cu storage pools inintestine, Cu depletion, accumulation of triglyceride-filled vesicles in enterocytes, mislocalization of apolipoprotein B, and loss of chylomicrons. In primary 3-dimensional enteroids, administration of excess Cu or Cu chelators impaired assembly of chylomicrons. ATP7B regulates vesicular storage of Cu in mouse intestine. ATP7B buffers Cu levels in enterocytes to maintain a range necessary for formation of chylomicrons. Misbalance of Cu and lipid in the intestine could account for gastrointestinal manifestations of Wilson disease.

Efficiency of Polychaete Nereis (Neanthes) Succinea as Biomonitor for Heavy Metals Pollution in the Red Sea, Egypt

Polychaetes nereids groups are the most common in shallow marine habitats and abundant in benthic communities. This group was proved to tolerate a high burden of heavy metals within their tissues. The current work assesses the effect of water criteria; sea water temperature, hydrogen ion concentration (pH), dissolved oxygen concentration, turbidity, conductivity and salinity on the uptake and storage of four heavy metals; Mn,, Pb, Cd and Cu in tissues of the marine polychaete worm Nereis succinea collected from two sites at Hurghada, Red sea; the Marine Biological Station (MBS) and the Fishing Port at Sakala (FPS). Bioaccumulation Factors (BAFs) were determined to evaluate the capability of the investigated annelid worm to accumulate heavy metals, so as to be used as sentinel species for monitoring metal pollutants. Population density of the investigated polychaete was determined at both studied sites as related to water criteria. ANOVA statistical analysis has indicated significant higher concentration of Mn, Pb, Cd and Cu in water at FBS than MBS (P<0.01) and high tissue concentration of Mn, Cd, Pb and Cu at individuals collected from FBS (P<0.01). The highest value of annual mean of BAF at <i>Nereis</i> tissues were recorded for Cu (1023.09±816.55), while the lowest BAF was for Pb (162.97±118.03). Polychaete abundance was significantly higher at MBS. Significant effect was found for water criteria on metal bioaccumulation and population density of <i>Nereis</i>. Data were discussed to evaluate the sensitivity of <i>N. succinea</i> to heavy metal pollutants and its possible use as biological monitor for metal contaminants at marine habitats.

Some trace element content in tissues honeybees under feeding, sugar syrup, meal soya and citrate Co and Ni

The results of studies of the effect feeding bees sugar syrup with the addition of flour from soybeans varieties Chernivtsi–9, and various amounts of «nanoakvatsytrats» Co and Ni in terms thermostat on the content of Fe, Co, Cu, Zn, Ni, Cd and Pb in tissues honeybees. In the first period studies found significantly higher levels of Co and Zn Cu amid falling in the tissues of bees III –term groups fed meal from soybeans (25 g) and citrate Co (СоNTs) at a dose of 2 mg Co and Zn in II –s group. Under the influence soybean meal with addition of citrate Ni (NiNTs) at a dose of 1 mg Ni in group IV –s reduced content in tissues Fe, Co, Cu and Zn and rose – Ni and Pb. Citrate complex combination of Ni and Co in doses of 2 mg 1 mg Co and Ni in the V –s experimental group was accompanied by a decrease in content of Fe and Cu in tissues of bees against the background of the content of Co and Ni. Given the addition to the sugar syrup (SS) soybean meal (II gr.) and «nanoakvatsytrats» Co and Ni (III, IV and V g.) in the second period of research in the tissues of bees II gr. decreased levels of Fe, Co and Ni, and III of th (Co 2 mg) increased the content of Zn and Pb on the background of reduction of Ni. Noted lower content of Fe, Co and Zn in the tissues of bees IV and V groups and Cu – V group only against the back ground of these groups content Ni.

Concentrations of Heavy Metals in Commercially Important Oysters from Goa, Central-West Coast of India.

The major beds of oyster along the central-west coast of India are exposed to different anthropogenic activities and are severely exploited for human consumption. In this viewpoint, tissues of oyster Crassostrea madrasensis, C. gryphoides and Saccostrea cucullata were analyzed for Cu, Ni, Cd and Pb concentrations (dry weight) from Chicalim Bay, Nerul Creek and Chapora Bay in pre-monsoon, monsoon and post-monsoon seasons. A higher concentration of Cu (134.4-2167.9mg kg-1) and Cd (7.1-88.5mg kg-1) was found, which is greater than the recommended limits in all the three species (and sites). Moreover, significant (p < 0.05) variations were observed for all the metals concentrations among the species, seasons and sites. The high concentrations of Cd and Cu in tissues of edible oyster pose a threat to human health. Therefore, continuous monitoring, people awareness and a stringent government policy should be implemented to mitigate the metal pollution along the studied sites.

Copper Bioaccumulation and Depuration in Common Carp (Cyprinus carpio) Following Co-exposure to TiO2 and CuO Nanoparticles.

Metal oxide nanoparticles (NPs), such as TiO2 and CuO, are widely applied in an increasing number of products and applications, and therefore their release to the aquatic ecosystems is unavoidable. However, little is known about joint toxicity of different NPs on tissues of aquatic organisms, such as fish. This study was conducted to assess the uptake and depuration of Cu following exposure to CuO NPs in the presence of TiO2 NPs in the liver, intestine, muscle, and gill of common carp, Cyprinus carpio. Carps with a mean total length of 23±1.5cm and mean weight of 13±1.3g were divided into 6 groups of 15 each (1 control group) and exposed to TiO2 NPs, CuO NPs, and a mixture of TiO2 and CuO NPs for periods of 20days for uptake and 10days for depuration. The determination of total Cu concentration was carried out by an ICP-OES. The order of Cu uptake in different tissues of the carps was liver>gill>muscle>intestine in both levels of CuO NPs alone; results showed that the total Cu concentrations in the presence of TiO2 nanoparticles were increased and were in the sequence of liver>gill>intestine>muscle. In depuration period, Cu concentrations were decreased in all treatments in the sequence of gill>intestine>muscle>liver. Uptake of Cu in different tissues of common carp increased with increasing concentration and time and was tissues- and time-dependent. In conclusion, this study suggested that the uptake of Cu in the tissues of common carp increased in the joint presence of TiO2 NPs.

Impact of copper (Cu) at the dose of 50 mg on haematological and biochemical blood parameters in turkeys, and level of Cu accumulation in the selected tissues as a source of information on product safety for consumers.

The current state-of the art points to a positive impact of copper (Cu) supplements on the general health status in poultry. Copper induces beneficial changes in the haematological and biochemical blood parameters. It also displays immunostimulating properties and helps maintain a proper microbiological balance in the digestive tract. The objective of this study was to investigate the impact of Cu at the dose of 50 mg/kg BW, administered in organic and inorganic form, on the haematological and biochemical blood parameters and level of Cu bioaccumulation in the liver and pectoral muscle. The study was carried out on 45 BUT-9 turkeys which had been were reared for 16 weeks. They were divided into 3 experimental groups: I - the control group; II - fed with CuSO4 at the dose of 50 mg Cu•dm (-3) H2O; III - received a Cu chelate with lysine at the same dose. The administration of Cu at the dose exceeding the nutritional recommendations did not induce beneficial changes in the examined birds. This indicates that it is not necessary to administer Cu doses higher than the recommended levels. The extent of Cu accumulation in the pectoral muscle increased by 40% compared to the control group, whereas in the liver it was higher by 30-35% than in the birds without Cu administration. The level of Cu in tissues does not pose a risk to consumers. The supplementation of Cu at the dose of 50 mg has a negative impact on the level of the analyzed parameters. The results of the presented study indicate that the administered Cu dose exceeds birds' demand for this element.

Heavy metal-induced oxidative damage is reduced by β-estradiol application in lentil seedlings

The protective effect of β-estradiol (E) application against heavy metal (HM) toxicity in lentil (Lens culinaris) seedlings was investigated. Seeds were treated with distilled water (control) or aqueous solutions of 100 μM CdCl2, 200 μM CuCl2 and 1 μM E singly or in combinations (1 μM E+100 μM CdCl2 and 1 μM E+200 μM CuCl2). HM treatments resulted in increase in the activities of antioxidative enzymes, including superoxide dismutase (SOD), catalase (CAT), guaicol peroxidase and ascorbate peroxidase. In a similar manner, Cd and Cu affected significantly oxidative injury indicators measured as electrolyte leakage (electrical conductivity of germination medium), lipoxygenase (LOX) activity and contents of malondialdehyde (MDA; lipoperoxidation marker), carbonyl groups (protein oxidation marker) and hydrogen peroxide (a reactive oxygen species). However, E was effective in reducing HM-induced toxicity. The steroid (1) alleviated HM-induced increase in the electrolyte leakage, LOX activity and contents of MDA, carbonyl and H2O2 and (2) improved the activities of SOD and CAT, but not the peroxidase ones, as compared to treatments with HM singly. In addition, E application prevented HM-induced decrease in dry weight production, but did not reduce the accumulation of Cd and Cu in tissues. Results of the present study suggest that E is able to protect lentil from HM-induced oxidative damage most likely by avoidance of H2O2 generation and improving antioxidative enzyme activities and, thereby, decreasing oxidative stress injury, but not by reducing Cd and Cu uptake.

Potential ofIgniscum sachalinensisL. andSalix viminalisL. for the Phytoremediation of Copper-Contaminated Soils

The potential ofSalix viminalisL. andIgniscum sachalinensisL. for phytoremediation of copper- (Cu-) contaminated soils was studied under greenhouse conditions. Approximately 5 kg of potted agricultural and sewage amended soils sampled from the top 0 to 20 cm depth in Neuruppin, Germany, was treated with CuSO4at concentrations 0 (control), 250, 750, and 1250 mg Cu kg−1soil and ethylenediaminetetraacetic acid (EDTA) at 1000 mg kg−1soil, respectively. Each plant species was grown on four replicates of each soil treatment. Copper accumulated in aboveground tissues tends to increase with increasing soil Cu concentration and was the lowest in stem and leaf of both plant species grown on control soils. At 750 and 1250 mg Cu kg−1soil, Cu accumulated in stem and leaf ofI. sachalinensisincreased by over 12- and 20-fold, respectively, whereas there was no vegetative growth inS. viminalisbeyond 250 mg Cu kg−1soil. Application of EDTA to sewage amended soils increased Cu accumulated in the stem and leaf, especially inI. sachalinensis. In general,I. sachalinensisseems to have the potential to tolerate high soil Cu content and simultaneously bioaccumulate Cu in tissues and thus may have better prospects for phytoremediation.

Alteration of benthic communities associated with copper contamination linked to boat moorings

AbstractAlthough copper (Cu) is an essential element for life, leaching from boat paint can cause excess environmental loading in enclosed marinas. The effects of copper contamination on benthic macrofaunal communities were examined in three San Diego Bay marinas (America's Cup, Harbor Island West and East) in Southern California, USA. The distribution of Cu concentration in sediments exhibited a clear spatial gradient, with hotspots created by the presence of boats, which in two marinas exceeded the effect range medium (ERM). Elevated sediment Cu was associated with differences in benthic assemblages, reduced species richness and enhanced dominance in America's Cup and Harbor Island West, whereas Harbor Island East did not appear to be affected. At sites without boats there were greater abundances of some amphipods such as the species Desdimelita sp., Harpinia sp., Aoroides sp., Corophium sp., Podocerus sp., bivalves such as Lyonsia californica, Musculista senhousia, Macoma sp., and polychaetes such as Diplocirrus sp. In contrast, at sites with boats, densities of Pseudopolydora paucibranchiata, Polydora nuchalis, Euchone limnicola, Exogone lourei, Tubificoides spp. were enhanced. The limited impact on Harbor Island East suggests not only lower Cu input rates and increased water flushing and mixing, but also the presence of adequate defense mechanisms that regulate availability and mitigate toxic impacts. At all three marinas, Cu in tissues of several macrobenthic species exhibited Cu bioaccumulation above levels found in the surrounding environment. The annelids Lumbrineris sp. and Tubificoides spp., and the amphipod Desdimelita sp. contained high levels of Cu, suggesting they function as Cu bioaccumulators. The spionid polychaetes Polydora nuchalis and Pseudopolydora paucibranchiata had much lower Cu concentrations than surrounding sediments, suggesting they function as Cu bioregulators. The macrobenthic invertebrates in San Diego Bay marinas that tolerate Cu pollution (e.g. P. nuchalis, P. paucibranchiata, Euchone limnicola, Typosyllis sp., Tubificoides sp.) may function as indicators of high‐Cu conditions, whereas the presence of Cu‐sensitive species (e.g. Podocerus sp., Aoroides sp., Harpinia sp., Macoma sp., Lyonsia californica) may indicate healthier conditions (less Cu‐stressed). Parallel responses by faunas of Shelter Island Yacht Basin, also in San Diego Bay, suggest potential for development of regional Cu contamination assessment criteria, and call for functional comparisons with other marinas and coastal water bodies.

The Role of Antioxidative Enzymes in Copper Tolerance Strategy of Mimosaceace prosopis farcta Growing in a Copper Mine

In this study, we determined the accumulation levels of copper in tissues and the status of antioxidant enzyme activities in Mimosa­ceace prosopis fracta against Cu-toxicity in a copper mine. We measured the level of chlorophyll and the activities of superoxide dismutase, glutathione peroxidase and catalase by spectrometry, malondialdehyde and dityrosine by HPLC and the levels of Cu in tissues and soils by atomic absorption spectrometry. Total and available copper were at toxic levels for plants growing in contaminated soil (zone 1). However, there were no visual or conspicuous symptoms of Cu-toxicity in plant species. Excess copper was transferred into C. ambrosioides tissues. The Mimosaceace prosopis fracta accumulated Cu in roots and then in leaves, in which the leaves’ chloroplasts stored Cu to approximately two times that of vacuoles. In zone 1, the chlorophyll levels increased significantly in leaves of Mimosaceace prosopis fracta with respect to the same plant growing in uncontaminated soil (zone 2). The studied plants in zone 1 revealed a significant increase in tissue antioxidant enzyme activities in comparison with the same plants in zone 2. The levels of oxidative damage biomarkers of lipids, such as MDA and proteins such as dityrosine, were higher in tissues of Mimo­saceace prosopis fracta that were grown in zone 1 as compared to the same plant species in zone 2, though this difference was not significant. The levels of these biomarkers were higher in roots, stems and leaves, respectively, in both zones. There were significant differences between roots and leaves for these parameters. We concluded that elevation of antioxidative enzyme activities was a tolerance strategy in the studied plants that protected them against copper toxicity.

The copper tolerance strategies and the role of antioxidative enzymes in three plant species grown on copper mine

This study was undertaken to identify the strategies and the status of antioxidant enzyme activities involved in three plant species tolerance against Cu-toxicity in copper mine. The following methods were used for evaluations in three wild type species; Datura stramonium, Malva sylvestris and Chenopodium ambrosioides. The level of chlorophyll and the activities of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) by spectrometry, malondialdehyde (MDA) and dityrosine by HPLC and the levels of Cu in tissues and soils by atomic absorption spectrometry (AAS). Analysis showed that total and available copper were at toxic levels for plants growing on contaminated soil (zone 1). However, there were not any visual and conspicuous symptoms of Cu toxicity in plant species. Among three species, excess copper was transferred only into the D. stramonium and C. ambrosioides tissues. The C. ambrosioides accumulated Cu in roots and then in leaves, in which the leaves chloroplasts stored Cu around two times of vacuoles. In D. stramonium most of Cu was accumulated in leaves in which the storage rate in vacuoles and chloroplasts were 42% and 8%, respectively. In zone 1, the chlorophyll levels increased significantly in leaves of C. ambrosioides with respect to the same plant growing on uncontaminated soil (zone 2). There was insignificant decrease in chlorophyll content of D. stramonium leaves, collected from zone 1 with respect to zone 2. The D. stramonium and C. ambrosioides in zone 1, both revealed significant increase in their tissues antioxidant enzyme activities in comparison with the same samples of zone 2. There was significant elevation in oxidative damage biomarkers; MDA and dityrosine, when the aerial parts of D. stramonium in zone 1 were compared with the same parts of zone 2. We concluded that there were different tolerance strategies in studied plant species that protected them against copper toxicity. In M. sylvestris, exclusion of Cu from the roots or its stabilization in the soil restricted Cu toxicity effects. On the other hand D. stramonium and C. ambrosioides, elevated their antioxidative enzyme activities in response to cu-toxicity. In addition, the species D. stramonium accumulated excess of Cu in leaves vacuoles.

Comparing Copper Requirements of Faba Bean, Chickpea, and Lentil with Spring Wheat

The copper (Cu) requirement of four crop species was measured in a glasshouse experiment using yield of dried shoots and Cu content (Cu concentration multiplied by yield of dried shoots) of 62 day old plants grown in two different alkaline soils. The species compared were faba bean (Vicia faba L. cv. Fiord), chickpea (Cicer arietinum L. cv. Tyson), lentil (Lens culinaris Medik cv. Digger), and spring wheat (Triticum aestivum L. cv. Stretton). The comparative Cu requirement of the species was determined from yields of dried shoots when no Cu fertilizer was applied, the amount of applied Cu required to produce the same percentage of the maximum (relative) yield of dried shoots, and the Cu content of dried shoots. The concentration of Cu in youngest tissue and in dried shoots was used to determine critical concentrations of Cu in tissue associated with 90% of the maximum yield. Faba bean used indigenous soil Cu more effectively than wheat, followed by chickpea and then lentil. As measured using both shoot yield and Cu content in shoots, the Cu requirement was lowest for faba bean, and increased in the order faba bean < wheat < chickpea < lentil. Copper concentration in dried youngest tissue and in dried shoots increased with an increase in the amount of added Cu. The critical Cu concentration in the youngest tissue was (mg Cu/kg): 4.6 for lentil, 2.6 for chickpea, 1.5 for wheat, and 2.8 for faba bean; corresponding values for dried shoots (mg Cu/kg) were 6.3 for lentil, 3.3 for chickpea, 2.8 for wheat, and 3.0 for faba bean.

Forms of Cd, Cu, Pb, and Zn in soil and their uptake by cereal crops when applied jointly as carbonates

The cereal crops (barley -Hordeum vulgare L., maize -Zea mays L., wheat -Triticum vulgare L.) were grown in a greenhouse using a sandy soil type treated with various doses of cadmium carbonate (salt), copper carbonate (malachite), lead carbonate (cerussite), and zinc carbonate (smithsonite), added jointly. The following levels of these metals were used: Cd − 5, 10, 50μg g−1 soil; Cu and Pb - 50,100, 500 μg g−1 soil; Zn-150, 300, 1500 μg g-1 soil. Sequential extraction was adopted to partition the metals into five operationally-defined fractions: exchangeable, carbonate, Fe-Mn oxides, organic, and residual. The residual was the most abundant fraction in the untreated (control) soil for all the metals studied (50 to 60% of the total metal content). The concentrations of exchangeable Cd, Cu, Pb, and Zn were relatively low in untreated soil but increased (over the three year period) in treated soils for Cd, Zn, and Cu, whereas only small changes were observed for Ph. This experiment showed a significant increase in Cd, Zn, and Cu in tissue of plants grown on the treated soil, but a non-significant change in plant tissue with respect to Pb concentration.

Concentrations and distribution of Fe, Zn and Cu in tissues of the white sucker (Catostomus commersoni) in relation to elevated levels of metals and low pH

Concentrations and distribution of Fe, Zn and Cu in tissues of the white sucker (Catostomus commersoni) in relation to elevated levels of metals and low pH

Studies of the changes in systemic copper metabolism and excretion produced by the intravenous administration of trithiomolybdate in sheep

1. The effects of intravenous trithiomolybdate administration on the fate of 64Cu and on stable Cu metabolism were examined in sheep held in metabolism cages and fed on a low-Cu diet supplying 2.95 mg Cu/animal per d. 2. In Expt 1 the injection of trithiomolybdate, 30 mg molybdenum/sheep per d for 5 d, greatly increased plasma Cu levels and more than doubled the faecal Cu excretion. Urinary Cu excretion was unaffected. The disappearance from plasma of 64Cu injected during the trithiomolybdate administration was slowed although faecal 64Cu excretion was increased more than threefold. 3. In Expt 2 trithiomolybdate, 10 and 30 mg Mo/sheep per d for 3 d, was administered 22 h after the injection of 64Cu. Radioactivity reappeared immediately in plasma and faecal 64Cu excretion was increased. 4. In both experiments the 64Cu and the increased stable Cu in plasma were associated with albumin. 5. The experiments explain the effectiveness of thiomolybdates as 'decoppering' agents and provide a model for some of the systemic effects seen in ruminants exposed to increased dietary Mo. The experiments support the view that the thiomolybdates, by causing the appearance of new ligands, alter the distribution of Cu in tissues and cause an overall depletion.

Metabolic interactions between lead and copper in rats ingesting lead acetate

The effects of Pb ingestion with and without concurrent dietary Cu supplementation were determined on parameters associated with Cu deficiency in rats fed a nutritionally adequate diet. Groups of weanling male Sprague-Dawley rats were fed a purified (AIN-′76) diet and given Pb (0 or 500 ppm) and Cu (0, 6, or 12 ppm) as the acetate salt in deionized drinking water for 5 wk. A Pb-induced Cu deficiency resulted that was characterized by decreased levels of Cu in tissue and blood, decreased activities of the Cu-dependent enzymes, ceruloplasmin (serum) and Superoxide dismutase (erythocytes), and increased concentration of Fe in liver. These effects of Pb were prevented completely or in part by concurrent Cu supplementation. The Pb-induced decrease in hemoglobin and hematocrit values and the decrease in weight gain were not prevented by Cu supplementation of the diet and can therefore be assumed to be the direct result of a toxic effect of Pb. Although Pb ingestion resulted in decreased concentration of Cu in blood and tissue, additional dietary Cu had no effect on Pb levels.

Interactions between cadmium and zinc in cytoplasm of duck liver and kidney

Ducks were collected from a marine environment known to be polluted with heavy metals. Gel elution profiles were determined for both liver and kidney tissue using Sephadex G-75 gel. Zn increased linearly on the high molecular weight protein pool until this pool was apparently Zn saturated; saturation levels were 0.06 μmole cytoplasmic Zn/g kidney (wet wt.) and 0.14 μmole cytoplasmic Zn/g liver (wet wt.). Seventy-five percent of cytoplasmic Cd was found on the high molecular weight protein pool unless it was Zn saturated. If this pool was Zn saturated, then excesses of Zn and up to 75% of cytoplasmic Cd appeared on metallothionein. Results are discussed in terms of a competition of Cd and Zn for Zn binding sites on metalloenzymes. Cu increased linearly on both the high molecular weight protein pool and metallothionein, with increases of Cu in tissue.