BioMetals
A cobalt-resistant strain of Neurospora crassa (cor) was obtained by repeated subculturing of the wild type on cobalt-containing agar medium. N. crassa cor is twentyfold more resistant to cobalt ions compared with the wild type. Resistance was stable on repeated subculturing of cor on cobalt-free media. N. crassa cor is also cross-resistant to nickel (fourfold), but not to zinc or copper. Higher concentrations...
Aluminium uptake from blood into tissues of control and homozygous hypotransferrinaemic (hpx/hpx) mice, following continuous intravenous infusion of Al and Ga, has been compared with that of gallium, a proposed tracer for aluminium. Al uptake into tissues of control (hpx/+ and +/+) mice occurred in the order (expressed as a space): bone 464.7ml 100g; renal cortex 102.9ml 100g; liver 13.0ml 100g; spleen...
Most siderophores are catabolism resistant because of their non-peptidic or cyclic peptide chemical structures. Siderophore degradation is thus a rare event, and one which has received little attention. Based on literature precedence and the generation of monohydroxamic acid(s) by cell-free extracts of a deferrioxamine B degrading bacterium, a catabolic scheme of the siderophore is proposed. Data...
Extracts from the unicellular green alga Selenastrum capricornutum exhibit high superoxide dismutase activity, but only traces of catalase activity. The excess hydrogen peroxide (HO) generated by the superoxide dismutase in S. capricornutum may be degraded by a unique peroxidase. This peroxidase has a high specificity for ascorbate as its electron donor. The enzyme has an optimum pH at 8, is insensitive...
Isothermal remanent magnetization (IRM) acquisition and alternating field (A.F.) demagnetization analyses were performed on human heart, spleen and liver samples resected from cadavers. The magnetic properties of the samples were measured both at 77K and at 273K. A.F. demagnetization was performed at 273K. Results from the analyses of the tissue indicate the presence of ferromagnetic, fine-grained,...
The Al site structure of serum transferrin and lactoferrin is investigated using X-ray absorption near edge structure (XANES) spectroscopy. Al K-edge spectra in the mono- and dialuminum forms of the proteins have been recorded for the first time. Our results show that the aluminium ion is hexa-coordinated in an octahedral-like symmetry and that the monoaluminum form, where only the C-terminal binding...
Nicotinic acid has functional groups capable of forming complexes with trace metals. The present study examines the effect of nicotinic acid supplementation on absorption and utilization of zinc and iron. In vitro zinc uptake by human erythrocytes was studied using blood samples of 10 healthy subjects. It was found that 8 μmoles nicotinic acid or NADP increased 65Zn uptake by 38.9% and 43.1% in fasting,...
The dependence on pH of the absorption and circular dichroic spectra of iron(III), cobalt(III) and copper(II) transferrins has been (re)investigated. In the alkaline region, the CD profiles of iron(III) and cobalt(III) transferrin are essentially pH independent up to pH 11; only for very high pH values (pH > 11) is breakdown of the cobalt(III) and iron(III) transferrin derivatives observed, without...
Effects of Pb2+, Ni2+, Hg2+ and Se4+ on cultured human glioma U-343MG cells were investigated considering uptake, toxicity and, in combination with radiation, clonogenic cell survival. The cells were exposed to 0-100 μm of the metals for a week before the evaluation. The tests showed a tendency to toxicity with 10 μm nickel although not significant (P > 0.05). Selenium, lead and mercury exerted...
A copper-deprived form of the enzyme Cu, Zn superoxide dismutase was identifiedin the liver of rats made copper-deficient by dietary restriction. In homogenates ofsuch livers Cu, Zn superoxide dismutase presents a dis-homogeneous electrophoreticprofile with respect to the native enzyme. When rat liver extracts were treated withexogenous copper an electrophoretic pattern resembling the native one was...
The influence of application of skin-lightening creams and dental amalgam fillings on the urinary mercury (Hg) level was evaluated in 225 females (ages 17 to 58 years) living in Riyadh, capital of Saudi Arabia. The arithmetic mean of the urinary Hg level was 6.96 ± 20.43 μg l, in the range 0 to 204.8 μg l. The mean urinary Hg level adjusted by creatinine (Cr) was 11.22 ± 37.23 μg g Cr, in the range...
Oysters display a diversity of uptake mechanisms for metallic elements and distribution in the target organs, namely gills and the digestive gland. Various tissues of the flat oyster, Ostrea edulis, were studied following experimental exposure to 0.025 μm (5 μg l) of mercury, for up to 34 days. All animals survived the treatment. Data indicate Hg accumulation in gill tissue with a maximum concentration...
The use of the iron chelator deferiprone (L, CP20, 1,2-dimethyl-3-hydroxypyrid-4-one) for the treatment of diseases of iron overload and other disorders is problematic and requires further evaluation. In this study the efficacy, toxicity and mechanism of action of orally administered L were investigated in the guinea pig using the carbonyl iron model of iron overload. In an acute trial, depletion...
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...
Spectroscopic techniques were used to investigate the interaction between vanadate and human erythrocyte ghosts. Direct evidence from 51V nuclear magnetic resonance (NMR) studies suggested that the monomeric and polymeric vanadate species may bind to the anion binding sites of band 3 protein of the erythrocyte membrane. The results of 51V NMR studies and the quenching effect of vanadate on the intrinsic...
The effects of three recently synthesized zinc-saccharide complexes (zinc-fructose, zinc-galactose and zinc-glucose) on blood δ-aminolevulinic acid dehydratase (ALAD) activity, glutathione (GSH), zinc-protoporphyrin (ZPP) and urinary δ-aminolevulinic acid (ALA) levels have been investigated to ascertain the utility of these complexes as zinc supplements and as preventive agents against lead intoxication...
An attenuation (or reversion) of the prolytic effect of lead on neonatal red cells is observed in iso- or hypotonic low ionic strength media. This effect correlates neither with concomitant activation of K+ (Ca2+ or Pb2+) channels nor with volume reduction. Neonatal erythrocytes were used in this study owing to their greater cellular density, as compared with adult red cells, for the above mentioned...
Twenty-four brands of commercial infant milk formula were collected and analysed for selenium by inductively coupled plasma spectrometry with the hydride t-system after an acid digestion procedure. The mean selenium concentration was 49.0 ± 11.55 μg l, with a range from 26-68 μg l, resulting in an adequate daily selenium intake for infants aged from zero to six months consuming 0.75 l milk daily as...