The limits of copper homeostatic regulation in humans are not known, making it difficult to define the milder effects of early copper excess. Furthermore, a robust assay to facilitate the detection of early stages of copper excess is needed. To address these issues, we assessed changes in relative mRNA abundance of methallothionein 2A (MT2A), prion (PrP), amyloid precursor-like protein 2 (APLP2...

The effect of copper on photoinhibition of photosystem II in vivo was studied in bean (Phaseolus vulgaris L. cv Dufrix). The plants were grown hydroponically in the presence of various concentrations of Cu2+ ranging from the optimum 0.3 &mgr;m (control) to 15 &mgr;m. The copper concentration of leaves varied according to the nutrient medium from a control value of 13 mg kg-1 dry weight to 76 mg...

The basic amino acid histidine inhibited yeast cell growth more severely than lysine and arginine. Overexpression of CTR1, which encodes a high-affinity copper transporter on the plasma membrane, or addition of copper to the medium alleviated this cytotoxicity. However, the intracellular level of copper ions was not decreased in the presence of excess histidine. These results indicate that hist...

The ctpA (ccoI) gene product, a putative inner membrane copper-translocating P1B-type ATPase present in many bacteria, has been shown to be involved only in the cbb(3) assembly in Rhodobacter capsulatus and Bradyrhizobium japonicum. ctpA was disrupted in Rubrivivax gelatinosus, and the mutants showed a drastic decrease in both cbb(3) and caa(3) oxidase activities. Inactivation of ctpA results a...

Copper is an essential ion that forms part of the active sites of many proteins. At the same time, an excess of this metal produces free radicals that are toxic for cells and organisms. Fish have been used extensively to study the effects of metals, including copper, present in food or the environment. It has been shown that different metals induce different adaptive responses in adult fish. Ho...

INTRODUCTION There have been many reports and papers on deficient, normal and high levels of copper in patients with thalassemia major. The aim of this study is to evaluate copper status in a series of more than 300 patients with thalassemia major and determine the degree of copper deficiency or excess. METHODS Three hundred and seventy patients with thalassemia major over 5 years of age were...

Drosophila melanogaster MTF-1 (dMTF-1) is a copper-responsive transcriptional activator that mediates resistance to Cu, as well as Zn and Cd. Here, we characterize a novel cysteine-rich domain which is crucial for sensing excess intracellular copper by dMTF-1. Transgenic flies expressing mutant dMTF-1 containing alanine substitutions of two, four or six cysteine residues within the sequence (54...

Copper is an essential micronutrient for most living organisms, serving as a redox-active cofactor for important enzymes such as the terminal respiratory oxidases and superoxide dismutase. However, in excess copper can be extremely toxic, due in part to this same redox-activity by which copper ions can catalyse the production of deleterious reactive oxygen species (ROS), and also due to its pro...

Iost toxic diseases can be divided into those which result from consumption or exposure to toxic chemicals or poisonous plants. They can be prevented by limiting access to these chemicals and plants. Copper Toxicity, Causes— (a) excessive copper ingestion, (b) absence of sufficient molybdenum in diet, (c) injury to liver tissue from plant alkaloids enabling the liver to store excess copper, (d)...