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The metabolism-independent metal binding characteristics of Ulva lactuca were investigated using both freeze-dried thalli and cell walls stripped of intracellular material by incubation in Triton-X followed by methanol. Biosorption of Cd, Zn, Cu and Co by freeze-dried thallus was concentration-dependent and followed Freundlich and Langmuir isotherms. The Freundlich plot suggested that freeze-dried...
Three non-identical Zn-resistant strains of Neurospora crassa have been isolated. ZNR-1 and ZNR-2 strains were obtained after repeated subculturing of wild type N. crassa on Zn-containing agar media (8mM and 16mM), while ZNR-3 was isolated after mutagenesis with diethyl sulfate, followed by selection on Zn agar plates (16mM). All three ZNR strains showed two- to threefold resistance to Zn in liquid...
Exogenously administered zinc compounds have been shown to possess antiulcer activity in the development of gastric lesions. The aim of this study was to investigate the effects of zinc sulphate pretreatment of rats on cysteamine-induced duodenal ulcers and to correlate them with changes in zinc serum and tissue levels. Atomic absorption spectrophotometry was used to determine zinc serum and tissue...
The excretion of mercury, copper and zinc in urine, and mercury in whole blood andplasma, was determined in 40 chloralkali workers exposed to mercury vapour and 40age-matched referents. The Hg concentrations in whole blood, plasma and urine werehigher in the exposed group (35 nmol l, 30 nmol l,and 11.5 nmol mmol creatinine, respectively) in comparison with thereference group (15 nmol l, 6.3 nmol l,...
Autopsied liver tissue samples collected from 42 males and 31 females were analyzed for copper, manganese and zinc using atomic absorption spectrometry (AAS). With the exception of two liver samples for which the copper levels were determined to be 74.8 and 104.0 μg/g (dry weight), hepatic copper concentrations were found to range from 1.7 to 32.4 μg/g with a mean concentration of 14.2 μg/g and standard...
Acute or chronic zinc administration may cause hyperglycemia in experimental animals. These findings are attributed to permissive actions of glucocorticoids and glucagon upon hepatic gluconeogenesis and glycogenolysis. The effect of Zn++ on plasma glucose, C-peptide, glucagon, and cortisol was investigated in healthy and insulin-dependent diabetes mellitus (IDDM) patients. Ten normal individuals (5...
The aim of this study was to measure the distribution of mercury, in tissues of rats exposed to amalgam over a two months period. Possible interaction of mercury with copper and zinc in organs was also evaluated. Rats were either exposed to mercury from 4 dental amalgams, or fed the diet containing powdered amalgam during two months. Mercury was measured in the kidney, liver and brain, copper in kidney...
The uptake, intracellular distribution and cytotoxicity of high doses of extracellular zinc was investigated in C6 rat glioma cells. Net zinc uptake occurred only above certain thresholds in time and concentration, below them no alterations of the intracellular zinc level were observed. These results were obtained by measurements with the fluorescent dye Zinquin and by atomic absorption spectrometry,...
Zinc is an essential trace element for the immune system, but also very important in other organ systems. Every highly proliferating cell system is dependent on sufficient availability of zinc. During the last decades the influence of zinc on various cell systems have been investigated. Multiple effects of exogenously added zinc have been described in in vitro culture systems and in in vivo systems...
The essential role of zinc in embryogenesis was identified through studies of its presence in eggs and embryos, the effects of its deficiency and its role in metallo proteins required for organ development and formation. The Xenopus laevis oocyte zinc content varies during oogenesis. It increases from 3 to 70 ng zinc/oocyte as it progresses from stage I to VI. The oocyte zinc is derived from the maternal...
The biological role of the zinc(II) ion has been recognized in DNA and RNA synthesis, apoptosis, gene expression, or protein structure and function. Therefore, development of useful zinc(II) sensors has recently been attracting much interest. Chemistry for selective and efficient detection of trace Zn2+ is a central issue. Recently, various types of zinc-fluorophores are emerging, comprising bio-inspired...
In addition to its diverse role in many physiological systems, zinc (Zn) has now been shown to be an important regulator of apoptosis. The purpose of this review is to integrate previously published knowledge on Zn and apoptosis with current attempts to elucidate the mechanisms of action of this biometal. This paper begins with an introduction to apoptosis and then briefly reviews the evidence relating...
Zinc metabolism in higher eukaryotes is complex, being controlled by uptake, efflux, and storage in individual cells, as well as in peripheral tissues and organs. Recently there have been advances in the understanding of the genes involved in these processes and their regulation. Metal-response element-binding transcription factor-1 (MTF-1) functions as a cellular zinc sensor which coordinates the...
Measurement of free zinc levels and imaging of zinc fluxes remains technically difficult due to low levels and the presence of interfering cations such as Mg and Ca. We have developed a series of fluorescent zinc indicators based on the superb sensitivity and selectivity of a protein, human apo-carbonic anhydrase II, for Zn(II). These indicators transduce the level of free zinc as changes in intensity,...
Zinc is essential for cell proliferation and differentiation, especially for the regulation of DNA synthesis and mitosis. On the molecular level, it is a structural constituent of a great number of proteins, including enzymes of cellular signaling pathways and transcription factors. Zinc homeostasis in eukaryotic cells is controlled on the levels of uptake, intracellular sequestration in zinc storing...
The last ten years have witnessed major advances in our understanding of zinc transporters and their regulation in eukaryotic organisms. Two families of transporters, the ZIP (Zrt-, Irt-like Protein) and CDF (Cation Diffusion Facilitator) families, have been found to play a number of important roles in zinc transport. These are ancient gene families that span all phylogenetic levels. The characterized...
Zn2+ homeostasis in bacteria is achieved by export systems and uptake systems which are separately regulated by their own regulators. Three types of Zn2+ export systems that protect cells from high toxic concentrations of Zn2+ have been identified: RND multi-drug efflux transporters, P-type ATPases, and cation-diffusion facilitators. The RND type exporters for Zn2+ are only found in a few gram-negative...
The induction of apoptotic cell death by cadmium was investigated in eight mammalian cell lines. Great differences in the cytotoxicity of cadmium were found with different cell lines: Rat C6 glioma cells turned out to be most sensitive with an IC50-value of 0.7 μM, while human A549 adenocarcinoma cells were relatively resistant with an IC50-value of 164 μM CdCl2. The mode of cadmium-induced cellular...
The maintenance of Mg2+ homeostasis in the plant is essential for viability. This review describes Mg2+ functions and balancing in plants, with special focus on the existing knowledge of the involved transport mechanisms. Mg2+ is essential for the function of many cellular enzymes and for the aggregation of ribosomes. Mg2+ concentrations also modulate ionic currents across the chloroplast and the...
Zinc gets into the brain parenchyma across the blood-brain and the blood-cerebrospinal fluid barriers, while cadmium hardly gets into the brain parenchyma. Because histidine may be involved in zinc transport across the brain barrier systems, the binding to histidine was compared between zinc and cadmium to understand the difference in brain permeability to both metals. Sephadex G-10 gel filtration...
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