tepe sagzabad, a site situated on the qazvin plain of north-central iran, was excavated from 1970 to 1998 by the institute ofarchaeology of tehran university. recent excavations by h. tala’i (1997-1999) yielded some metal artifacts dating to theearly iron age. ten of these copper-based samples were investigated using inductively coupled plasma optical emissionspectroscopy (icp-oes), scanning el...

In this work, copper micropillars and copper-carbon nanotube (CNT) composite micropillars were fabricated by incorporating an electrodeposition technique with a xurography process. In order to disperse carbon nanotubes in copper-CNT micropillars, various amounts of CNTs were added to the electroplating bath. Surface morphology and phase characterization of copper micropillars and copper-CNT com...

OWEN, CHARLES A., JR., and JANE B. HAZELRIG. Copper deJi&nc~ and copper toxicify in the rat. Am. J, Physiol. 215(Z) : 334-338. I968.-Changes in metabolism of an intravexmusly injected tracer dose of 64Cu were measured in Sprague-Dawley rats subjected to copper loading, by addition of cupric acetate to the drinking water, or made copper deficient, by use of a milk-powder diet and copper-free wat...

An experiment was conducted using a total of 420, 1-d-old, Arbor Acres commercial male chicks to compare copper sulfate and tribasic copper chloride (TBCC) as sources of supplemental copper for broilers. Chicks were randomly allotted to 1 of 7 treatments for 6 replicates of 10 birds each and were fed a basal corn-soybean meal diet (11.45 mg/kg copper) supplemented with 0, 150, 300, or 450 mg/kg...

Gulf toadfish were exposed to sublethal levels of copper (12.8 or 55.2 microM) for 30 days. Drinking in control fish averaged 1 ml kg(-1)h(-1) but exposure to 55.2 microM copper resulted in a complex biophasic pattern with initial (3 h and 1 day) inhibition of drinking rate, followed by an elevation of drinking rate from day 3 onwards. Drinking led to copper accumulation in the intestinal fluid...

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...