BioMetals
Cells of the root nodule bacterium Rhizobium leguminosarum bv. viciae WSM710 were cultured in a medium containing 20 μM 57Fe. Mössbauer spectra of the cells at 5.5 and 3.7 K indicated that the major form of iron present in the cells was in the form of polynuclear iron(III) clusters. At 5.5 K the spectral component associated with these clusters was in the form of a superposition of a broad feature...
The redox properties of the copper in particulate methane monooxygenase from Methylosinus trichosporium OB3b were investigated. The ESR spectrum of the pMMO-containing membranes from M. trichosporium OB3b indicated a typical type II copper (II) signal (g∥ = 2.24, A∥ = 18.4 mT, g⊥ = 2.06, α2= 0.84). By anaerobic addition of excess amounts of duroquinol, an optimum reductant of pMMO, the ESR spectra...
Isothermal remanent magnetization was measured in 14 Wistar and five Porton rat brains. Results indicate that magnetic iron biominerals are present in most of the samples and the formation of these minerals in the rat brain is influenced by transfusion and dietary iron loading when compared to control samples. The high level of consistency in the concentrations and the lack of magnetic material in...
Fourteen samples of human hippocampal tissue were resected during amygdalo-hippocampectomies performed on patients suffering from Mesial Temporal Lobe Epilepsy (MTLE). In addition, eight tissue samples from the hippocampus, cortex basalganglia, cerebellum and leptomeninges were resected from cadavers during routine autopsy and were not chemically fixed. All samples were preserved in liquid nitrogen...
Recovery of metal values from sulfide ores by use of acidophilic microorganisms is gaining importance. A number of commercial/pilot plants are setup to find out the techno-economic feasibility of the overall process. The main drawback in the process is the slow kinetics of dissolution of metal values from the sulfide ores. To make the technology e attractive the kinetics should be improved considerably...
Metallothionein (MT) and cadmium (Cd) contents were determined in the subcellular fractions of the liver and kidneys of bank voles exposed for 6 weeks to elevated levels of dietary Cd-40 and 80 μg g-1 dry weight. Hepatic and renal MT was detected exclusively in the cytosol, while Cd was found in the cytosol (73–79% of the total content), nuclei (14–18%) and particulates (4–9%). The concentration of...
p-azidobenzoyloxy desferriferricrocin (AF) 2, a photoactivatable analog of ferrichrome, was prepared by selective acylation of the serine group of ferricrocin 1 in two steps: transesterification of ferricrocin followed by demetallation. A model compound, (L) 2-benzyloxycarbonylamino-3-p-azidobenzoyloxy N-isopropyl propionamide 8, was separately synthesized in order to set up optimal transesterification...
Arsenic is ubiquitous in the biosphere and frequently reported to be an environmental pollutant. Global cycling of arsenic is affected by microorganisms. This paper describes a new bacterial strain which is able to efficiently oxidize arsenite (As[III]) into arsenate (As[V]) in liquid medium. The rate of the transformation depends on the cell density. Arsenic species were separated by high performance...
The kinetic properties of the Mg2+-activated and Mn2+-activated glutamine synthetase (GS) of Azospirillum brasilense in the biosynthetic reaction were studied. The Mg2+-supported and Mn2+-supported GSs in an average state of adenylylation varied in pH optimum, maximum activity, saturation functions for ammonium and glutamate, affinity to substrates, and in the Me2+-ATP ratio required for the optimal...
Reverse transcription (RT) PCR technique was used to investigate the mechanism of apoptosis induced by Cd and the change of its related genes in testes and prostate of rats. Adult male rats were given a single (s.c.) injection of CdC l2 0, 2.5, 5.0, 10 μmol/kg. 48 h and 72 h after administration of Cd, animals were sacrificed. The results indicated that Cd can induce apoptosis in testes via p53-independent...
Female Porton rats have been treated with either parenteral iron (intraperitoneal red cells) or dietary iron (carbonyl iron) for up to 12 months or 22 months respectively. In the parenteral iron loaded animals, the liver iron concentration rose from approximately 2 mg g-1 dry wt at 2 months to 21 mg g-1 dry wt at 12 months, while for the dietary iron loaded animals, this value rose from 14 to 48 mg...
The effect of iron ions on particulate methane monooxygenase was studied by using the EDTA-treated membranes from Methylosinus trichosporium OB3b. When the membrane was treated with EDTA the activity remained 82% of the as-isolated membranes, and the activity of the EDTA-treated membranes was strongly influenced by the addition of metal ions. Among the metal ions, ferric, ferrous and cupric ions stimulated...
Copper(II) complexes of diclofenac with interesting anti-inflammatory profiles have been prepared and studied by infrared and electronic spectroscopy. In the solid state and in polar and coordinating solvents, all the complexes are solvated binuclear carboxylato-bridged complexes, [Cu(L)2(S)]2, where L is monodeprotonated diclofenac and S is the axially bonded solvent. The effect of the copper(II)...
From the culture medium of Ralstonia (formerly Burkholderia or Pseudomonas) pickettii DSM 6297 grown under iron-limited conditions an iron complexing compound (siderophore) could be isolated. The structure of the isolated polycarboxylate siderophore was determined by spectroscopic methods as S,S-rhizoferrin, the enantiomer of R,R-rhizoferrin produced by fungi (Zygomycetes). Transport experiments with...
The purpose of this study was to investigate if the intestinal absorption of copper in drinking water is altered in the presence of complexing agents from a fulvic acid mixture and an infant formula powder. Ten to twelve day old rat pups were given a single oral dose of radio-labeled Cu in deionized water (0.93 mg Cu/l), in water containing fulvic acids (10 mg/l), in infant formula mixed with deionized...
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...
With a view to using bile acids as shuttles for delivering platinum-related cytostatic drugs to liver tumors, a chenodeoxycholylglycinato(CDCG)-derivative of platinum(II) has been synthesized. The complex - named Bamet-M2- was chemically characterized by elemental analysis, FT-IR, NMR, FAB-MS, and UV spectroscopy. The results indicate the following composition: C26H42N2O5Cl2NaPt(II), the metal Pt(II)...
The biological activity of six synthetic siderophore analogues (two dihydroxamates, two trihydroxamates, one tetrahydroxamate and one 3-hydroxy-4(1H)pyridinone) has been studied in Escherichia coli, Morganella morganii 13 and Proteus mirabilis 8993 strains by using growth promotion tests. Various transport-deficient mutants of E. coli were used to study the route of entry into gram-negative bacteria...
Intrinsic steady-state fluorescence of lactoperoxidase (LPO) and its ligand-bound complexes has been characterized as a structural probe of its structure in solution. On excitation at 295 nm, a broad emission maximum is observed around 338 nm for LPO and for its ligand-bound complexes. The quantum yield is 0.0185±0.0005 for LPO and indicates tryptophan → heme energy transfer. Tryptophan residues are...
The metal-binding ability of Aspergillus niger mycelial waste was improved by chemical modification. The latter was performed by introducing additional carboxy groups using oxidation methods or the introduction of the ethyldiamino group first by chlorination of A. niger using mesyl chloride and subsequent reaction of the product with ethylene diamine. Metal binding abilities of the products for Cd...