Cadmium accumulation and interactions with zinc, copper, and manganese, analysed by ICP-MS in a long-term Caco-2 TC7 cell model

The influence of long-term exposure to cadmium (Cd) on essential minerals was investigated using a Caco-2 TC7 cells and a multi-analytical tool: microwave digestion and inductively coupled plasma mass spectrometry. Intracellular levels, effects on cadmium accumulation, distribution, and reference concentration ranges of the following elements were determined: Na, Mg, Ca, Cr, Fe, Mn, Co, Ni, Cu, Zn, Mo, and Cd. Results showed that Caco-2 TC7 cells incubated long-term with cadmium concentrations ranging from 0 to 10 lmol Cd/l for 5 weeks exhibited a significant increase in cadmium accumulation. Furthermore, this accumulation was more marked in cells exposed long-term to cadmium compared with controls, and that this exposure resulted in a significant accumulation of copper and zinc but not of the other elements measured. Interactions of Cd with three elements: zinc, copper, and manganese were particularly studied. Exposed to 30 lmol/l of the element, manganese showed the highest inhibition and copper the lowest on cadmium intracellular accumulation but Zn, Cu, and Mn behave differently in terms of their mutual competition with Cd. Indeed, increasing cadmium in the culture medium resulted in a gradual and significant increase in the accumulation of zinc. There was a significant decrease in manganese from 5 lmol Cd/l exposure, and no variation was observed with copper. Abbreviation: AAS – Atomic absorption spectrometry; CRM– Certified reference material; PBS – Phosphate buffered saline without calcium and magnesium; DMEM – Dubelcco’s modified Eagle’s medium

Enhancement of stripping technique for copper(II) detection in water sample using N,N’-bis(2-hydroxy-4-methoxyacetophenone)ethylenediamine (BME)

A highly sensitive, rapid, simple and selective stripping assay for the determination of trace copper(II) is proposed. The selectivity and sensitivity of the electroanalytical process on a glassy carbon (GC) electrode were enhanced using the newly synthesized Schiff base N,N’-bis(2-hydroxy-4-methoxyacetophenone)ethylenediamine (BME). The methodology is based on the accumulation of copper(II)–BME complex onto the GC electrode, followed by electrochemical oxidation of the adsorbed species. The effect of experimental parameters such as pH, BME concentration, scan rate, accumulation time and accumulation potential on the sensitivity of copper(II) detection were investigated. Under the optimal conditions, BME has successfully enhanced the copper(II) detection using the GC electrode by nearly 95% with detection limit (LOD) of 2.6 ngL−1. The effects of interfering ions such as Cd(II), Zn(II), Fe(II), Cr(III) and Pb(II) were also investigated. The applicability of this technique was illustrated by the determination of copper(II) ion in tap water

Spin injection and spin accumulation in permalloy-copper mesoscopic spin valves

We study the electrical injection and detection of spin currents in a lateral spin valve device, using permalloy (Py) as ferromagnetic injecting and detecting electrodes and copper (Cu) as non-magnetic metal. Our multi-terminal geometry allows us to experimentally distinguish different magneto resistance signals, being 1) the spin valve effect, 2) the anomalous magneto resistance (AMR) effect and 3) Hall effects. We find that the AMR contribution of the Py contacts can be much bigger than the amplitude of the spin valve effect, making it impossible to observe the spin valve effect in a 'conventional' measurement geometry. However, these 'contact' magneto resistance signals can be used to monitor the magnetization reversal process, making it possible to determine the magnetic switching fields of the Py contacts of the spin valve device. In a 'non local' spin valve measurement we are able to completely isolate the spin valve signal and observe clear spin accumulation signals at T=4.2 K as well as at room temperature. We obtain spin diffusion lengths in copper of 1 micrometer and 350 nm at T=4.2 K and room temperature respectively.Comment: 8 pages (incl. figures), 7 figures, RevTex, conferenc

Single-crystal field-effect transistors based on copper phthalocyanine

Copper phthalocyanine (Cu-Pc) single crystals were grown by physical vapor transport and field effect transistors (FETs) on the surface of these crystals were prepared. These FETs function as p-channel accumulation-mode devices. Charge carrier mobilities of up to 1 cm2/Vs combined with a low field-effect threshold were obtained. These remarkable FET-characteristics, along with the highly stable chemical nature of Cu-Pc make it an attractive candidate for device applications

Copper-induced oxidative stress in three-spined stickleback : relationship with hepatic metal levels

International audienceThe aim of this study was to characterise biomarker responses in three-spined sticklebacks exposed to copper. For this purpose, adult sticklebacks were exposed for 3 weeks to copper sulphate at 0. 25 100 and 200 mug L-1 as Cu. At days 4, 8, 12 and 21. several parameters were measured including liver, gonad and spleen somatic indexes, hepatic biomarkers (catalase (CAT), superoxide dismutase (SOD). glutathione peroxidase (GPx), glutathione (GSH), glutathione-S-transferase (GST) and 7-ethoxyresorufin-O-deethylase (EROD)) and hepatic copper and zinc concentrations. Copper induced a rapid and transient increase of antioxidant enzymes and a depletion of gluiathione content during the first 8 days of exposure. Significant copper and zinc accumulation in fish liver were observed for the two higher exposure concentrations after 8 and 12 days, respectively. This study showed that copper induced an oxidative stress in fish liver before significant metal accumulation in the liver could be detected, suggesting the involvement of differential mechanisms in copper uptake and metabolism. Three-spined stickleback appears to be a sensitive model to stud), oxidative stress induced by metals

Heavy metal bioaccumulation by the important food plant, olea europaea L., in an ancient metalliferous polluted area of Cyprus

Aspects of the bioaccumulation of heavy metals are reviewed and possible evidence of homeostasis is highlighted. Examination and analysis of olive (Olea europaea L.) trees growing in close proximity to a copper dominated spoil tip dating from at least 2000 years BP, on the island of Cyprus, revealed both bioaccumulation and partitioning of copper, lead and zinc in various parts of the tree. A factor to quantify the degree of accumulation is illustrated and a possible seed protective mechanism suggested

Genome wide association mapping of grain arsenic, copper, molybdenum and zinc in rice (Oryza sativa L.) grown at four international field sites

Peer reviewedPublisher PD

Cu2+ uptake by Chlorococcum hemicolum - A Xeric Chlorophycean Alga

Bioremediation of copper by xeric chlorophycean bioremediator, Chlorococcum hemicolum was investigated. The growth rates at various concentrations of Cu2+ were assessed in terms of protein level and 8 mg L-1 (37.67 % level in growth kinetics) is the tolerance limit. Absorption/adsorption kinetics was estimated after 240 hrs of Cu2+ treatments. Absorptions were higher than adsorption with maximum accumulation factor (AF) of 1.40. The Cu2+ concentration and absorption were linearly related (r = 0.99; p>0.01). Other biochemical parameters like total sugar, chlorophyll and carotenoids were also quantified to correlate the state of metabolism and these exhibited reduction due to heavy metal stress