Showing papers on "Vanadate published in 2008"
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01 Jan 2008
TL;DR: In this article, the authors present a method for the analysis of Vanadium-Carbon Bond and Vanadate-dependent Haloperoxidases in biological systems, using 51V NMR Spectroscopy and optical spectroscopy.
Abstract: Preface. 1. Introduction and Background. 1.1. History. 1.2. Occurrence, Distribution and Impact. 2. Inorganic and Coordination Compounds of Vanadium. 2.1. Inorganic Aspects of the Function of Vanadium in Biological Systems. 2.2. Interaction of Aqueous Vanadate and Vanadyl with Biogenic Ligands. 2.3. Vanadium Coordination Compounds. 2.4. The Vanadium-Carbon Bond. 3. Physico-chemical Methods for the Characterisation of Native and Model Vanadium Compounds. 3.1. 51V NMR Spectroscopy. 3.2. NMR of Other Nuclei. 3.3. EPR Spectroscopy. 3.4. ESEEM and ENDOR Spectroscopies. 3.5. Optical Spectroscopies. 3.6. X-ray Absorption Spectroscopy. 4. Naturally Occurring Vanadium Compounds. 4.1 Vanadium in Ascidians and Polychaeta Worms. 4.2. Amavadin. 4.3. Vanadate-dependent Haloperoxidases. 4.4. Vanadium and the Nitrogen Cycle. 4.5. Vanadate as Energiser for Bacteria, and Vanadophores. 5. Inferences of Vanadium Compounds on Cellular Functions. 5.1. Medicinal Aspects of Vanadium. 5.2. Interaction of Vanadium with Proteins and Protein Substrates. 6. Epilogue. References. Index.
351 citations
TL;DR: Findings call for a reassessment of conclusions on the role of the PTP in cell death that are based on the effects of CsA or of CyP-D ablation, as well as a rethink of current treatments for PTP desensitization.
169 citations
TL;DR: Ultrasensitive surface-enhanced Raman scattering signals of four typical analytes were observed on Ag nanoparticles from beta-silver vanadate and copper, even though the concentrations of these Analytes were as low as 1 x 10(-16) M (Rhodamine 6G or crystal violet) and 1x 10(-15)M (trinitrotoluene or bovine serum albumin).
114 citations
TL;DR: Different spectroscopic methods were applied to study the effects of the interaction of vanadyl and vanadate species with BSA, considered as the most abundant plasma protein.
98 citations
TL;DR: The effects of equal doses of two different metals intravenously injected in the same fish species and upon the same exposure period are described for the first time to understand the mechanisms of vanadate and cadmium toxicity in fish cardiac muscle.
Abstract: Several biological studies associate vanadium and cadmium with the production of reactive oxygen species (ROS), leading to lipid peroxidation and antioxidant enzymes alterations. The present study aims to analyse and compare the oxidative stress responses induced by an acute intravenous exposure (1 and 7 days) to a sub-lethal concentration (5 mM) of two vanadium solutions, containing different vanadate n -oligomers ( n = 1–5 or n = 10), and a cadmium solution on the cardiac muscle of the marine teleost Halobatrachus didactylus (Lusitanian toadfish). It was observed that vanadium is mainly accumulated in mitochondria (1.33 ± 0.26 μM), primarily when this element was administrated as decameric vanadate, than when administrated as metavanadate (432 ± 294 nM), while the highest content of cadmium was found in cytosol (365 ±231 nM). Indeed, decavanadate solution promotes stronger increases in mitochondrial antioxidant enzymes activities (catalase: + 120%; superoxide dismutase: + 140%) than metavanadate solution. On contrary, cadmium increases cytosolic catalase (+ 111%) and glutathione peroxidases (+ 50%) activities. It is also observed that vanadate oligomers induce in vitro prooxidant effects in toadfish heart, with stronger effects induced by metavanadate solution. In summary, vanadate and cadmium are differently accumulated in blood and cardiac subcellular fractions and induced different responses in enzymatic antioxidant defence mechanisms. In the present study, it is described for the first time the effects of equal doses of two different metals intravenously injected in the same fish species and upon the same exposure period allowing to understand the mechanisms of vanadate and cadmium toxicity in fish cardiac muscle.
97 citations
TL;DR: Nuclear magnetic resonance (NMR) measurements were made on aqueous vanadate solutions to characterize speciation as a function of pH and vanadates concentration as mentioned in this paper, and potentiodynamic polarization measurements were carried out on Al alloy 2024-T3 in 50 mM NaCl solutions.
Abstract: Nuclear magnetic resonance NMR measurements were made on aqueous vanadate solutions to characterize speciation as a function of pH and vanadate concentration. Additionally, potentiodynamic polarization measurements were carried out on Al alloy 2024-T3 in 50 mM NaCl solutions in which pH and vanadate concentration were systematically varied. Results showed that inhibition by vanadates occurred mainly in alkaline solutions where tetrahedrally coordinated vanadates, metavanadate and pyrovanadate, were abundant. Inhibition was not observed in solutions where octahedrally coordinated decavanadates predominated. Anodic inhibition, in the form of increased pitting potential, was observed in both aerated and deaerated solutions. In contrast, cathodic inhibition was observed only in aerated solutions acting primarily through the suppression of oxygen reduction. Energydispersive spectroscopy, used to collect chemical maps from aluminum coupons exposed to vanadate solutions, showed the suppression of Al2CuMg particle dissolution compared to vanadate-free solutions. NMR measurements were also used to track changes in vanadate speciation with time, pH adjustment, and with exposure to metallic aluminum surfaces. NMR showed noninhibiting octahedrally coordinated decavanadates rapidly decompose into inhibiting tetrahedrally coordinated metavanadates and pyrovanadates after alkaline pH adjustment. While decomposition begins immediately upon pH adjustment, equilibrium may not be reached even after significant time periods. © 2008 The Electrochemical Society. DOI: 10.1149/1.2907772 All rights reserved.
87 citations
TL;DR: All experiments indicate that boron stimulates an electrogenic transport system in the plasma membranes which is sensitive to vanadate and has a pH optimum around 7, i.e. the plasma membrane H+-ATPase.
Abstract: The stimulation of the plasma membrane (PM) H+-ATPase by boric acid was studied on a microsomal fraction (MF) obtained from ungerminated, boron-dependent pollen grains of Lilium longiflorum Thunb. which usually need boron for germination and tube growth. ATP hydrolysis and H+ transport activity increased by 14 and 18%, respectively, after addition of 2-4 mM boric acid. The optimum of boron stimulation was at pH 6.5-8.5 for ATP hydrolysis and at pH 6.5-7.5 for H+ transport. No boron stimulation was detected when vanadate was added to the MF, whereas an increase of 10-20% in ATP hydrolysis and H+ transport was still measured in the presence of inhibitors specific for V -type ATPase (nitrate and bafilomycin) and F-type ATPase (azide), respectively. A vanadate-sensitive increase in ATP hydrolysis activity was also observed in partially permeabilized vesicles (0.001%[w/v] Triton X-100) suggesting a direct interaction between borate and the PM H+-ATPase rather than a weak acid-induced stimulation. Additionally, we measured the effect of boron on membrane voltage (Vm) of ungerminated pollen grains and observed small hyperpolarizations in 48% of all experiments. Exposing pollen grains to a more acidic pH of 4 caused a depolarization, followed in some experiments by a repolarization (21%). In the presence of 2 mM boron such hyperpolarizations, perhaps caused by an enhanced activity of the H+-ATPase, were measured in 58% of all tested pollen grains. The effects of boron on Vm may be reduced by additional stimulation of a K+ inward current of opposite direction to the H+-ATPase. All experiments indicate that boron stimulates an electrogenic transport system in the plasma membrane which is sensitive to vanadate and has a pH optimum around 7, i.e. the plasma membrane H+-ATPase. A boron-increased PM H+-ATPase activity in turn may stimulate germination and growth of pollen tubes.
67 citations
TL;DR: In conclusion, VO43– induces eryptosis at least partially through increase of cytosolic Ca2+ concentration, an effect presumably contributing to the development of anemia in chronic renal failure.
Abstract: Vanadium, a trace element, as vanadate (VO43–) is known to interfere with a wide variety of enzymes including Ca2+ ATPase and Na+/K+ ATPase. VO
59 citations
TL;DR: The present account is a focused and critical review of the current knowledge of the interplay of bacteria and other primitive forms of life (cyanobacteria, algae, fungi and lichens) with vanadium, with the aim of provide perspectives for applications and further investigations.
Abstract: The two predominant forms of vanadium occurring in the geo-, aqua- and biosphere, soluble vanadate(V) and insoluble oxovanadium(IV) (vanadyl), are subject to bacterial activity and transformation. Bacteria belonging to genera such as Shewanella, Pseudomonas and Geobacter can use vanadate as a primary electron acceptor in dissimilation or respiration, an important issue in the context of biomineralisation and soil detoxification. Azotobacter, which can employ vanadium as an essential element in nitrogen fixation, secretes a vanadophore which enables the uptake of vanadium(V). Siderophores secreted by other bacteria competitively (to ferric iron) take up vanadyl and thus interfere with iron supply, resulting in bacteriostasis. The halo-alkaliphilic Thioalkalivibrio nitratireducens possibly uses vanadium as a constituent of an alternative, molybdopterin-free nitrate reductase. Marine macro-algae can generate a variety of halogenated organic compounds by use of vanadate-dependent haloperoxidases, and a molecular vanadium compound, amavadin, from Amanita mushrooms has turned out to be an efficient catalyst in oxidation reactions. The present account is a focused and critical review of the current knowledge of the interplay of bacteria and other primitive forms of life (cyanobacteria, algae, fungi and lichens) with vanadium, with the aim to provide perspectives for applications and further investigations.
57 citations
TL;DR: Investigation of the toxicity to neonatal rat ventricular myocytes of two vanadate solutions containing different oligovanadates distribution found mitochondrial membrane depolarization was an early event in decavanadates- and monovanadate-induced necrotic cell death of cardiomyocytes.
Abstract: Besides the well-known inotropic effects of vanadium in cardiac muscle, previous studies have shown that vanadate can stimulate cell growth or induce cell death. In this work, we studied the toxicity to neonatal rat ventricular myocytes (cardiomyocytes) of two vanadate solutions containing different oligovanadates distribution, decavanadate (containing decameric vanadate, V 10) and metavanadate (containing monomeric vanadate and also di-, tetra-, and pentavanadate). Incubation for 24 h with decavanadate or metavanadate induced necrotic cell death of cardiomyocytes, without significant caspase-3 activation. Only 10 microM total vanadium of either decavanadate (1 microM V 10) or metavanadate (10 microM total vanadium) was needed to produce 50% loss of cell viability after 24 h (assessed with MTT and propidium iodide assays). Atomic absorption spectroscopy showed that vanadium accumulation in cardiomyocytes after 24 h was the same when incubation was done with decavanadate or metavanadate. A decrease of 75% of the rate of mitochondrial superoxide anion generation, monitored with dihydroethidium, and a sustained rise of cytosolic calcium (monitored with Fura-2-loaded cardiomyocytes) was observed after 24 h of incubation of cardiomyocytes with decavanadate or metavanadate concentrations close to those inducing 50% loss of cell viability produced. In addition, mitochondrial membrane depolarization within cardiomyocytes, monitored with tetramethylrhodamine ethyl esther or with 3,3',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolcarbocyanine iodide, were observed after only 6 h of incubation with decavanadate or metavanadate. The concentration needed for 50% mitochondrial depolarization was 6.5 +/- 1 microM total vanadium for both decavanadate (0.65 microM V 10) and metavanadate. In conclusion, mitochondrial membrane depolarization was an early event in decavanadate- and monovanadate-induced necrotic cell death of cardiomyocytes.
57 citations
TL;DR: The results show that two simple coordination complexes with known insulin enhancing effects can invoke a response in calcium homeostasis and the regulation of muscle contraction through the SR Ca (2+)-ATPase.
Abstract: The general affinity of the sarcoplasmic reticulum (SR) Ca 2+ -ATPase was examined for three different classes of vanadium coordination complexes including a vanadium(V) compound, pyridine-2,6-dicarboxylatodioxovanadium(V) (PDC-V(V)), and two vanadium(IV) compounds, bis(maltolato)oxovanadium(IV) (BMOV), and an analogue of amavadine, bis(N-hydroxylamidoiminodiacetato)vanadium(IV) (HAIDA-V(IV)). The ability of vanadate to act either as a phosphate analogue or as a transition-state analogue with enzymes’ catalysis phosphoryl group transfer suggests that vanadium coordination compounds may reveal mechanistic preferences in these classes of enzymes. Two of these compounds investigated, PDC-V(V) and BMOV, were hydrolytically and oxidatively reactive at neutral pH, and one, HAIDA-V(IV), does not hydrolyze, oxidize, or otherwise decompose to a measurable extent during the enzyme assay. The SR Ca 2+ -ATPase was inhibited by all three of these complexes. The relative order of inhibition was PDC-V(V) > BMOV > vanadate > HAIDA-V(IV), and the IC50 values were 25, 40, 80, and 325 µM, respectively. Because the observed inhibition is more potent for PDC-V(V) and BMOV than that of oxovanadates, the inhibition cannot be explained by oxovanadate formation during enzyme assays. Furthermore, the hydrolytically and redox stable amavadine analogue HAIDA-V(IV) inhibited the Ca 2+ -ATPase less than oxovanadates. To gauge the importance of the lipid environment, studies of oxidized BMOV in microemulsions were performed and showed that this system remained in the aqueous pool even though PDC-V(V) is able to penetrate lipid interfaces. These findings suggest that the hydrolytic properties of these complexes may be important in the inhibition of the calcium pump. Our results show that two simple coordination complexes with known insulin enhancing effects can invoke a response in calcium homeostasis and the regulation of muscle contraction through the SR Ca 2+ -ATPase.
TL;DR: The two structure types found in the (AX)2M-(VO3)2 series differ in the propagation direction of the metavanadate chains which is thought to be due to the presence (or absence) of a Jahn-Teller distortion of the metal.
Abstract: Three unique structure types of the vanadate-based mixed-metal oxide systems (salt)·MnII-Vv-O and (salt)·CuII-Vv-O are presented, with a focus on the role of the asym. vanadate units. Lattice parameters were obtained for (CsCl)2Mn(VO3)2, (CsBr)2Mn(VO3)2, (RbCl)2Mn(VO3)2, (CsCl)2Cu(VO3)2, (CsCl)Mn2(V2O7), (KCl)2Cu(VO3)2, (RbCl)2Cu(VO3)2 and (CsBr)2Cu(VO3)2. The two structure types found in the (AX)2M-(VO3)2 series differ in the propagation direction of the metavanadate chains which is thought to be due to the presence (or absence) of a Jahn-Teller distortion of the metal (d9 Cu2+ vs. d5 Mn2+) ion.
TL;DR: Vanadate administration could protect against direct action of lipid peroxidation on brain AChE and in this way, it might be useful in the prevention of cholinergic neural dysfunction, which is one of the major complications in diabetes.
TL;DR: In this paper, the performance of HK-40m alloy obtained from electrochemical noise technique and polarization curves during 24-hour exposure in high sulfate (80,mol% Na 2 SO 4 −20 ǫmol% V 2 O 5 ) and high vanadate ( 80,mol%, V 2O 5 −20 Ôm Na 2 S 4 ) molten salts at 700 õC were reported.
TL;DR: The copper vanadate deposited on ZSM-5 by the hydrothermal method evidences the best performance in the oxidation of toluene, and can be associated with the smaller size and higher dispersion of the particles on the support, which was confirmed by their better reducibility and higher band gap energy value compared with the other series of studied catalysts.
TL;DR: In this paper, the ammonium vanadates were synthesized by a simple hydrothermal method without the presence of catalysts or templates, and the final products were NH4V4O10 nanobelts, NH42V6O16·1.5H2O nanowires, and (NH4)6V10O28·6H 2O nanobundles, respectively, when the pH of the growth solution varied from 2.5 to 1.5.
TL;DR: Results corroborate the finding that the reductive EMF of VO(2+) is increased by the availability of a 7-coordinate V(III) product and constitute the new field of vanadium redox enzymology.
TL;DR: A cross-linked enzyme aggregate (CLEA) of 3-phytase was synthesised, which was incubated with vanadate and tested as a biocatalyst in the asymmetric sulfoxidation of thioanisole using hydrogen peroxide as the oxidant and showed a similar efficiency and asymmetric induction as the free enzyme.
TL;DR: A series of vanadate substituted hydroxyapatite was directly prepared by a simple hydrothermal method at low temperature (110-200 ǫ) in NaOH solutions for 14h.
TL;DR: It is concluded that chronic treatment with both vanadate solutions stimulated fish VSa13 cells proliferation and prevented ECM mineralization, representing a good alternative to mammalian systems.
Abstract: Vanadium, a trace metal known to accumulate in bone and to mimic insulin, has been shown to regulate mammalian bone formation using in vitro and in vivo systems. In the present work, short- and long-term effects of metavanadate (containing monomeric, dimeric, tetrameric and pentameric vanadate species) and decavanadate (containing decameric vanadate species) solutions on the mineralization of a fish bone-derived cell line (VSa13) were studied and compared to that of insulin. After 2 h of incubation with vanadate (10 μM in monomeric vanadate), metavanadate exhibited higher accumulation rates than decavanadate (6.85 ± 0.40 versus 3.95 ± 0.10 μg V/g of protein, respectively) in fish VSa13 cells and was also shown to be less toxic when applied for short periods. In longer treatments with both metavanadate and decavanadate solutions, similar effects were promoted: stimulation of cell proliferation and strong impairment (75%) of extracellular matrix (ECM) mineralization. The effect of both vanadate solutions (5 μM in monomeric vanadate), on ECM mineralization was increased in the presence of insulin (10 nM). It is concluded that chronic treatment with both vanadate solutions stimulated fish VSa13 cells proliferation and prevented ECM mineralization. Newly developed VSa13 fish cells appeared to be appropriate in the characterization of vanadate effects on vertebrate bone formation, representing a good alternative to mammalian systems.
TL;DR: In this paper, the catalysts were composed of different crystalline phases, namely ziesite, fingerite, blossite and other copper vanadium oxides, and the best catalytic performance was obtained with the material calcined at 320 and 400°C.
TL;DR: In this paper, the authors measured the heat conduction of laser vanadate crystals and their solid solutions in the temperature interval from 50 to 350 K. The empirical dependences of the Heat conduction along the crystallographic axes 100 and 001 on the composition of rare-earth vanadates Re'1-xRe''xVO4, are obtained.
Abstract: The heat conduction of laser vanadate crystals GdVO4 and YVO4 and their solid solutions is measured in the temperature interval from 50 to 350 K. Mixed rare-earth vanadates have the common chemical formula Re'1-xRe''xVO4, where Re' and Re'' are two or more types of ions from a series La3+, Pr3+, Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, Tm3+, Yb3+, Lu3+, Sc3+, Y3+. The heat conduction of Nd:YVO4 measured at room temperature proved to be more than twice higher than that reported in the literature and in certificate characteristics of laser Nd:YVO4 elements manufactured by numerous commercial companies. The empirical dependences of the heat conduction along the crystallographic axes 100 and 001 on the composition of rare-earth vanadates Re'1-xRe''xVO4, are obtained in the temperature interval from 200 to 350 K.
TL;DR: The data suggest that vanadate impairs ECM mineralization not only by interfering with regulatory pathways but also by inhibiting enzymatic activity of ALP, providing additional evidence for the conservation, throughout evolution, of mechanisms regulating chondrocyte proliferation and differentiation.
TL;DR: In the vanadate-inhibited phosphatases - structural analogs of the transition state in phosphoester hydrolysis by the native enzymes - the position of the axial histidine can also be taken by cysteinate or serinate, a fact which has implications for the insulin-mimetic potential ofVanadate.
TL;DR: This work shows that the rheological properties of the system depend on electrostatic interactions between [H(2)V(10)O(28)](4-) and positively charged gelatin chains, and proposes to analyze these results by considering that triple helix aggregates should persist because of decavanadate bridging, and that the nucleation of an extended triple helIX network may induce a strong modification of the vanadate cross-linker distribution in the system, or both.
Abstract: The influence of polyoxovanadate clusters ([H2V10O28]4−) on the thermo-reversible gelation of porcine skin gelatin solution (type A, Mw ≈ 40 000 g·mol−1, pH = 3.4 ≪ isoelectric point (IEP) ≈ 8) has been investigated as a function of temperature and vanadate concentration by combining rheology and microcalorimetry. This work shows that the rheological properties of the system depend on electrostatic interactions between [H2V10O28]4− and positively charged gelatin chains. In a first stage, we describe the renaturation of the gelatin triple helices in the presence of decavanadate clusters. We reveal that, when gelatin chains are in coil conformation (30 °C < T < 50 °C), the inorganic clusters act as physical cross-linkers that govern the visco-elastic properties of the mixture with an exponential dependence of the (G′, G′′) modulus with the vanadate concentration. Below 30 °C, we show that gelatin triple helix nucleation is slightly favored by the presence of vanadate, but above a helix concentration of 0.01...
TL;DR: The result suggesting that vanadium-induced amelioration of the diabetic state appears to be secondary to the preservation of a functional portion of the pancreatic beta-cells which initially survived STZ-toxicity provides new insight into the therapeutic treatment of diabetics with vanadium compounds.
TL;DR: A directed assembly process to form C4-symmetric, vanadate-centered quadruplexes, for the first time, from a given chiral oxidovanadium(V) complex allows for highly efficient K+- and Ag+-specific transport from aqueous phase containing three other alkali metal cations into organic solvents.
Abstract: A directed assembly process to form C4-symmetric, vanadate-centered quadruplexes, for the first time, from a given chiral oxidovanadium(V) complex allows for highly efficient K+- and Ag+-specific transport from aqueous phase containing three other alkali metal cations into organic solvents, reminiscent of the K+ specific transport exerted by four homochiral glycine residues of the opening site in KcsA membrane protein.
TL;DR: Yor1p also confers resistance to rhodamine 6G and to doxorubicin and protects cells, although weakly, against tetracycline, verapamil, eosin Y and ethidium bromide, and possible hypotheses accounting for substrate inhibition, rather than stimulation, of ATP hydrolysis by the membrane preparation are inspected.
TL;DR: The impermeant agent DIDS and suramin, an antagonist of P2 purinoreceptors and inhibitor of some ecto-ATPases, decreased the enzymatic activity in a dose-dependent manner, confirming the external localization of this enzyme.
TL;DR: A set of new diperoxovanadate(V) complexes with the dipeptides glycyl-glycine or glycyl−leucine as ancillary ligands of the type, A[VO(O2)2(peptide)(H2O)]· H2O, A = Na or K have been synthesized and characterized by elemental analysis, thermal analysis, magnetic susceptibility and spectral studies as mentioned in this paper.
Abstract: A set of new diperoxovanadate(V) complexes with the dipeptides glycyl–glycine or glycyl–leucine as ancillary ligands of the type, A[VO(O2)2(peptide)(H2O)] · H2O, A = Na or K have been synthesized and characterized by elemental analysis, thermal analysis, magnetic susceptibility and spectral studies. The complexes contain side-on bound peroxo groups and a dipeptide zwitterion as co-ligand, binding the metal center unidentately through O (carboxylate) atom. The compounds are highly stable toward decomposition in solutions of acidic as well as physiological pH and serve as weak substrates to catalase, undergoing degradation in the presence of the enzyme at a rate much slower than H2O2. The compounds stoichiometrically oxidize GSH to GSSG. On comparing the GSH oxidizing ability of these compounds with those of previously reported peroxotungsten compounds containing similar co-ligands, a significant difference was noted. The compounds induce a strong inhibitory effect on alkaline phosphatase activity with a potency higher than that of the free peptides, vanadate, or peroxovanadate.