A saturable and temperature-dependent copper uptake pathway has been identified in Chlamydomonas reinhardtii. The uptake system has a high affinity for copper ions (Km approximately 0.2 microM) and is more active in cells that are adapted to copper deficiency than to cells grown in a medium containing physiological (submicromolar to micromolar) copper ion concentrations. The maximum velocity of...

Here, we present further characterization of cryptococcal CUF1 in copper homeostasis. We demonstrated that CUF1 was involved both in copper acquisition and in copper detoxification in response to copper variation. This was verified by direct measurement of the quantity of intracellular copper with flame atomic absorption spectrometry (FAAS) and molecular evidence. In copper-limited growth, the ...

Copper is an essential but potentially toxic trace element. In Drosophila, the metal-responsive transcription factor (MTF-1) plays a dual role in copper homeostasis: at limiting copper concentrations, it induces the Ctr1B copper importer gene, whereas at high copper concentrations, it mainly induces the metallothionein genes. Here we find that, despite the downregulation of the Ctr1B gene at hi...

The cop operon of Enterococcus hirae controls cytoplasmic copper levels. It encodes two copper ATPases, a repressor, and the CopZ metallochaperone. Transcription of these genes is induced by copper. However, at higher copper concentrations, CopZ is degraded by a copper-activated proteolytic activity. This specific proteolysis of CopZ can also be demonstrated in vitro with E. hirae extracts. Gro...

Any metal in excess can be toxic; therefore, metal homeostasis is critical to bacterial survival. Bacteria have developed specialized metal import and export systems for this purpose. For broadly toxic metals such as copper, bacteria have evolved only export systems. The copper export system (cop operon) usually consists of the operon repressor, the copper chaperone, and the copper exporter. In...

Copper kills bacteria rapidly by a mechanism that is not yet fully resolved. The antibacterial property of copper has raised interest in its use in hospitals, in place of plastic or stainless steel. On the latter surfaces, bacteria can survive for days or even weeks. Copper surfaces could thus provide a powerful accessory measure to curb nosocomial infections. We here investigated the effect of...

the main aim of this research is to determine optimal leaching conditions; eh, ph and complexing agent concentrations, for recovery of copper from hydroxide sludges such as those produced by electroplating shops, metal finishers, treatment of acid mine drainage, and industrial wastewater in general. this has been preceded by a theoretical approach and numerical and computer calculation. potenti...

In plants, copper is an essential micronutrient required for photosynthesis. Two of the most abundant copper proteins, plastocyanin and copper/zinc superoxide dismutase, are found in chloroplasts. Whereas plastocyanin is essential for photo-autotrophic growth, copper/zinc superoxide dismutase is dispensable and in plastids can be replaced by an iron superoxide dismutase when copper is limiting....

Despite increased interest in the role of copper deficiency in clinical problems and an increased understanding of the physiological roles of copper, the diagnosis of a marginal deficiency has not been perfected. The use of non-standardized procedures and the effects of factors other than copper nutriture have impeded identification of the "ideal" indicator of copper nutritional status in adult...

Copper is essential but can be toxic even at low concentrations. Coping with this duality requires multiple pathways to control intracellular copper availability. Three copper-inducible promoters, controlling expression of six copper tolerance genes, were recently identified in Escherichia coli. The cue system employs an inner membrane copper transporter, whereas the cus system includes a tripa...