Anions (Total 61968 Papers Found)

Anions (61968 Papers Found)
Organic anion-transporting polypeptides (Oatps) are a rapidly growing gene family of polyspecific membrane transporters. In rat brain, Oatp1 (gene symbol Slc21a1) and Oatp2 (Slc21a5) are localized at the apical and basolateral domains, respectively, of the choroid plexus epithelium. Furthermore, Oatp2 is strongly expressed at the rat blood-brain barrier (BBB). This study localizes the human OATP (now called OATP-A; SLC21A3) at the BBB in humans. Furthermore, with the Xenopus laevis oocyte system ...
A method for the detection of trehalose-6-phosphate (T6P) in tissue of the model plant Arabidopsis thaliana is presented. Liquid-liquid extraction (LLE) and mixed mode solid-phase extraction (SPE) were used for sample pretreatment followed by anion exchange chromatography (AEC) coupled with electrospray ionization mass spectrometry (MS) for highly selective quantitative analysis. LLE of plant material was performed with chloroform/acetonitrile/water (3:7:16, v/v/v) followed by SPE with Oasis MAX ...
Vertebrate hemoglobins are tetramers made of two pairs of alpha and beta subunits each containing a hydrophobic pocket where a heme molecule binds tightly and allows for the reversible binding of oxygen. Both tertiary and quaternary structures are ideally suited for the loading and unloading of oxygen necessary for the metabolic requirements of the organisms. Starting from a single ancestor hemoglobin subunit, evolutionary processes have led to heterologous tetramers exhibiting a moderate oxygen ...
meso-Octamethyloctafluorocalixpyrrole, a simple tetrapyrrolic macrocycle, has been shown to function as both a chloride/nitrate and a chloride/bicarbonate antiport agent for lipid bilayer transmembrane anion transport. This is the first example of a synthetic macrocyclic pyrrole-based receptor capable of transmembrane bicarbonate transport. ...
Reactive oxygen species (ROS) are reactive derivatives of O2 metabolism, including superoxide anion, hydrogen peroxide, hydroxyl radical and nitric oxide. All types of vascular cells produce ROS, primarily via cell membrane-associated NAD(P)H oxidase. Cardiovascular diseases, such as hypertension, are associated with increased ROS formation (oxidative stress). Oxidative excess in the vasculature reduces levels of the vasodilator nitric oxide, causes tissue injury, promotes protein oxidation and ...
A suite of formation-water samples from Silurian-Devonian reservoirs in the Illinois basin has been analyzed for major, minor, and trace element concentrations and for H, 0, and Sr isotopic compositions in order to interpret origin of salinity and geochemical evolution of brine compositions in this evaporiteand shale-poor cratonic basin. Although chloride concentrations range from 2000 to 137,000 mg/L, Cl/Br ratios (29 1 Ifr 18) are consistent with those of seawater or seawater evaporated short ...
The success of recombinant protein expression/purification in Escherichia coli depends on a high-fidelity system rendering purified proteins free of confounding contaminants such as endotoxin. Here we report on the expression and purification of a cryptic plasminogen-derived domain, kringle 5, which was previously reported to specifically inhibit endothelial cell growth and, therefore, angiogenesis. Using a histidine (HIS)-tag expression and Ni(+)-NTA agarose purification system identical to pre ...
PURPOSE Mutations in SLC4A11, a member of the SLC4 superfamily of bicarbonate transporters, give rise to corneal endothelial cell dystrophies. SLC4A11 is a putative Na⁺ borate and Na⁺:OH⁻ transporter. Therefore we ask whether SLC4A11 in corneal endothelium transports borate (B[OH]₄⁻), bicarbonate (HCO3⁻), or hydroxyl (OH⁻) anions coupled to Na⁺. METHODS SLC4A11 expression in cultured primary bovine corneal endothelial cells (BCECs) was determined by semiquantitative PCR, SDS-PA ...
Histamine is stored in granules of mast cells and basophils and released by inflammatory mediators. It has the potential to intercept some of the HOCl generated by the neutrophil enzyme, myeloperoxidase, to produce histamine chloramine. We have measured rate constants for reactions of histamine chloramine with methionine, ascorbate, and GSH at pH 7.4, of 91 M(-1)s(-1), 195 M(-1)s(-1), and 721 M(-1)s(-1), respectively. With low molecular weight thiols, the reaction was with the thiolate and rates ...
1. The aim of this study was to assess the effects of treatment with isoproterenol (ISO, 0.3 mg kg-1 day-1, s.c.) for 7 days on the vascular reactivity of rat-isolated aortic rings. Additionally, potential mechanisms underlying the changes that involved the endothelial modulation of contractility were investigated. 2. Treatment with ISO induced cardiac hypertrophy without changes in haemodynamic parameters. Aortic rings from ISO-treated rats showed an increase in the contraction response to phen ...
Volume-regulated channels for anions (VRAC) / organic osmolytes (VSOAC) play essential roles in cell volume regulation and other cellular functions, e.g. proliferation, cell migration and apoptosis. LRRC8A, which belongs to the leucine rich-repeat containing protein family, was recently shown to be an essential component of both VRAC and VSOAC. Reduced VRAC and VSOAC activities are seen in drug resistant cancer cells. ANO1 is a calcium-activated chloride channel expressed on the plasma membrane ...
Cisplatin holds an illustrious position in the history of chemistry most notably for its role in the virtual cure of testicular cancer. Here we describe a role for this small molecule in cyanide detoxification in vivo. Cyanide kills organisms as diverse as insects, fish, and humans within seconds to hours. Current antidotes exhibit limited efficacy and are not amenable to mass distribution requiring the development of new classes of antidotes. The binding affinity of the cyanide anion for the p ...
Dichloroacetic acid (DCA) is a contaminant found in treated drinking water due to chlorination. DCA has been shown to be a complete hepatocarcinogen in both mice and rats. In this study we developed a rapid and sensitive high-performance liquid chromatography (HPLC) method to simultaneously detect DCA and its metabolites, oxalic acid, glyoxylic acid and glycolic acid in blood and urine samples of animals sub-chronically administered with DCA (2 g/l) in drinking water. Both urine and plasma sampl ...
The structures of deoxypeganine (DOP) hydrochloride and oxalate were solved by x-ray structure analysis. An infinite chain along the crystallographic c axis was formed in the crystal structure of DOP oxalate. A molecular framework consisting of Cl anions and DOP cation protonated at N1 was found in the structure of unhydrated DOP hydrochloride. The molecular packing of the “host” (DOP cation) was pseudoisostructural in the studied ion-molecular crystals but differed from other known DOP salt ...
Supporting-electrolyte solutions comprise chemically inert cations and anions, produced by salt dissolution, together with a reactive ionic species that may be consumed and generated on bounding ion-selective surfaces (e.g., electrodes or membranes). Upon application of an external voltage, a Faraday current is thereby established. It is natural to analyze this ternary-system process through a one-dimensional transport problem, employing the thin Debye-layer limit. Using a simple model of ideal ...
The hydroxide-mediated cleavage of ketones into alkanes and carboxylic acids has been reinvestigated and the substrate scope extended to benzyl carbonyl compounds. The transformation is performed with a 0.05 M ketone solution in refluxing xylene in the presence of 10 equiv of potassium hydroxide. The reaction constitutes a straightforward protocol for the synthesis of certain phenyl-substituted carboxylic acids from 2-phenylcycloalkanones. The mechanism was investigated by kinetic experiments wh ...
A new series of homo- and heterometallic oxalato-bridged dinuclear compounds of formulas [Et4N]4[MM'(ox)(NCS)8] ([Et4N]+ = [(C2H5)4N]+; ox = C2O4(2-)) with MM' = Cr(III)-Cr(III) (1), Fe(III)-Fe(III) (2), and Cr(III)-Fe(III) (3) is reported. They have been structurally characterized by infrared spectra and single-crystal X-ray diffraction. The three compounds are isostructural and crystallize in the orthorhombic space group Cmca with Z = 8, a = 16.561(8) A, b = 13.481(7) A, and c = 28.168(8) A fo ...
Carbanions are one of the most important reagents in synthetic organic chemistry. They act as a carbon nucleophile to form a carbon–carbon bond as a consequence of the highly polarized carbon–metal bonds (C M). The properties of polar carbon–metal bonds in a carbanionic species depend on the metallic counterpart, such as lithium, magnesium, copper, and zinc. The first two organometallic compounds directly attack the carbonyl group of a,b-unsaturated ketones, whereas the latter two react by ...
In order to elucidate active oxygen in liver diseases, activities, electrophoretic profiles and immunolocalization of superoxide dismutase (SOD) in human liver specimens were investigated. Activities and electrophoresis were studied using liver homogenates in 41 cases and immunolocalization of Cu, Zn SOD was observed in 87 cases. Total SOD activity in acute viral hepatitis (AVH) and fatty liver (FL) groups was significantly lower than that in non-specific reactive hepatitis (NSRH) group. Cu, Zn ...
  • Kwang Ha,
  • Acta crystallographica. Section E, Structure reports online
  • 2011
The asymmetric unit of the title compound, [MnI(C(8)H(6)N(4))(2)(H(2)O)]I·H(2)O, consists of a cationic Mn(II) complex, an I(-) anion and a solvent water mol-ecule. In the complex, the Mn(II) ion is six-coordinated in a distorted octa-hedral environment defined by four N atoms of the two chelating 2,2'-bipyrimidine (bpym) ligands, one I(-) anion and one O atom of a water ligand. The dihedral angle between the least-squares planes of the two bpym ligands [maximum deviation = 0.092 (7) Å] is ...
Many therapeutic proteins require appropriate glycosylation for their biological activities and plasma half life. Coagulation factor VIII (FVIII) is a glycoprotein which has extensive post-translational modification by N-linked glycosylation. The terminal sialic acid in the N-linked glycans of FVIII is required for maximal circulatory half life. The extent of FVIII sialylation can be determined by high pH anion-exchange chromatography coupled with a pulse electrochemical detector (HPAEC-PED), bu ...
Chagas' disease, a vector-transmitted infectious disease, is caused by the protozoa parasite Trypanosoma cruzi. Drugs that are currently available for the treatment of this disease are unsatisfactory, making the search for new chemotherapeutic agents a priority. We recently described the trypanocidal action of (-)-elatol, extracted from the macroalga Laurencia dendroidea. However, nothing has been described about the mechanism of action of this compound on amastigotes that are involved in the ch ...
Bursts of emissions of low-energy electrons, including interatomic Coulomb decay electrons and Auger electrons (0-1000 eV), as well as X-ray fluorescence produced by irradiation of large-Z element nanoparticles by either X-ray photons or high-energy ion beams, is referred to as the nanoradiator effect. In therapeutic applications, this effect can damage pathological tissues that selectively take up the nanoparticles. Herein, a new nanoradiator dosimetry method is presented that uses probes for ...
The dependence of the blockage of amphotericin B channel conductance on the concentration of inorganic anions is shown. A model of the interaction of amphotericin B channel with blocker ion is proposed. According to the model the blocker ion is bound to the charged groups of the channel entrance. The inorganic anions also interact with these groups and affect the blocker concentration near the channel entrance. ...
A reproducible Romanowsky-Giemsa staining (RGS) can be carried out with standardized staining solutions containing the two dyes azure B (AB) and eosin Y (EY). After staining, cell nuclei have a purple coloration generated by DNA-AB-EY complexes. The microspectra of cell nuclei have a sharp and intense absorption band at 18,100 cm-1 (552 nm), the so called Romanowsky band (RB), which is due to the EY chromophore of the dye complexes. Other absorption bands can be assigned to the DNA-bound AB cati ...
The present study was planned to study the effect of priming of BALB/c mice peritoneal polymorphs (PMNLs) by viable, heat killed and formaline fixed promastigotes of L. donovani and soluble extract of proteins of L. donovani promastigotes on their capacity to produce toxic oxygen radicals (TOR). TOR production was measured by superoxide dismutase (SOD), inhibitable cytochrome C reduction and nitroblue tetrazolium reduction tests. No significant stimulation or inhibition in SOD inhibitable cytoch ...
Ab initio, semiempirical, and HMO perturbation calculations were employed to assess the relative positioning of the closely situated low-lying unoccupied pi MOs a(2)(chi) and b(1)(psi) in 1,10-phenanthroline (phen) and its 3,4,7,8-tetramethyl (tmphen) and four symmetrical diaza derivatives (n,m-dap). Compared to a(2)(chi), the b(1)(psi) pi MO is distinguished by markedly higher MO coefficients at the chelating nitrogen pi centers in 1,10-positions; eventually, a higher Coulomb integral value at ...
We have elucidated excimer-mediated intramolecular electron transfer in cofacially stacked PBIs tethered by two phenylene-butadiynylene loops. The electron transfer between energetically equivalent PBIs is revealed by the simultaneous observation of the PBI radical anion and cation bands in the transient absorption spectra. The fluorescence decay time of the excimer states is in good agreement with the rise time of PBI radical bands in transient absorption spectra suggesting that the electron tr ...
Surface films play a key role in corrosion and osteointegration processes of titanium-based orthopedic implants. The influence of niobium and vanadium as alloying elements on titanium alloy passivity have been investigated in Hanks' Balanced Salt Solution (HBSS), at 37 degrees C and pH 6.9.Ti6Al4V and Ti6Al6Nb have been considered. The excellent passivating properties of the anodically formed Ti(IV)-based surface oxide film and high corrosion resistance of the Ti6Al6Nb alloy have been attributed ...
With regard to the stability of the NO. radical as a chemical entity, it is without doubt able to serve as an intra- as well as an intercellular messenger. The radical O2-., in contrast, does not seem to be suited to far-range signalling in the vascular system. Its short chemical half-life, which is limited by the presence of various reactive blood constituents to below 50 ms, results in a free diffusion path length of less than 40 microns, i.e. only the distance between just a few cells. While ...
Renal tubular acidosis (RTA) is a tubulopathy characterized by metabolic acidosis with normal anion gap secondary to abnormalities of renal acidification. RTA can be classified into four main subtypes: distal RTA, proximal RTA, combined proximal and distal RTA, and hyperkalemic RTA. Distal RTA (type 1) is caused by the defect of H(+) secretion in the distal tubules and is characterized by the inability to acidify the urine below pH 5.5 during systemic acidemia. Proximal RTA (type 2) is caused by ...
Laser photodissociation spectroscopy of the I-·thymine (I-·T) and I-·cytosine (I-·C) nucleobase clusters has been conducted for the first time across the regions above the electron detachment thresholds to explore the excited states and photodissociation channels. Although photodepletion is strong, only weak ionic photofragment signals are observed, indicating that the clusters decay predominantly by electron detachment. The photodepletion spectra of the I-·T and I-·C clusters display a pr ...
Structures and energetics of o-, m-, and p-quinonimide anions (OC6H4N-) and quinoniminyl radicals have been investigated by using negative ion photoelectron spectroscopy. Modeling of the photoelectron spectrum of the ortho isomer shows that the ground state of the anion is a triplet, while the quinoniminyl radical has a doublet ground state with a doublet-quartet splitting of 35.5 kcal/mol. The para radical has doublet ground state, but a band for a quartet state is missing from the photoelectro ...
This report is the summary of presentations at the symposium sponsored by the American Society for Pharmacology and Experimental Therapeutics, April 26-30, at Experimental Biology 2014 in San Diego, CA. The presentations focused on the role of transporters in imaging in health and disease and on assessing transporter function in vivo. Imaging is an important diagnostic tool in clinics and is a novel tool for in vivo visualization of transporter function. Many imaging substrates and endogenous ma ...
Americium-241 and plutonium determinations will become of greater importance over the coming decades as 137Cs and 241Pu decay. The impact of 137Cs on environmental chronology has been great, but its potency is waning as it decays and diffuses. Having 241Am and Pu as unequivocal markers for the 1963 weapon fallout maximum is important for short time scale environmental work, but a fast and reliable procedure is required for their separation. The developed method described here begins by digesting ...
Dienelactone hydrolase (DLH), an enzyme from the beta-ketoadipate pathway, catalyses the hydrolysis of dienelactone to maleylacetate. DLH is unusual because it is the only known naturally occurring enzyme which contains the catalytic triad Cys ... His ... Asp. This triad has previously been created artificially in the mutant serine proteases, thiol subtilisin and thiol trypsin. In both cases the mutant enzymes exhibited activities several orders of magnitude lower than the wild type enzymes; the ...
Protonation of trans-1,2-bis(4-pyridyl)ethylene (4,4'-bpe) with dilute sulfuric acid (33 %) afforded a protonated adduct [{4,4'-bpe⋅2 H+ }2 {HSO4 }-2 {SO4 }-2 {H2 O}2 ] (1). The neighboring olefinic bond in 1 is in a suitable range (3.931-4.064 Å) to undergo a photochemical [2+2] cycloaddition reaction. Upon irradiation with UV light (365 nm), 1 undergoes a molecular sliding involving the 4,4'-bpe⋅2 H+ units, affording 2, stabilized through OSO4 ⋅⋅⋅π interactions. Heating 1 ...
Glycosaminoglycans (GAGs) are a family of linear heteropolysaccharides made up of repeating disaccharide units that are found on the surface and extracellular matrix of animal cells. They are known to play a critical role in a wide range of cellular processes including proliferation, differentiation and invasion. To elucidate the mechanism of action of these molecules, it is essential to quantify their disaccharide composition. Analytical methods that have been reported involve either chemical o ...
A hydrotalcite with Mg/Al molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500 degrees C, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type. The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite (HTC-500) was ...
We have studied the photodissociation and recombination dynamics of the diatomic anions X(2)(-) and XY(-) designed to mimic I(2)(-) and ICl(-), respectively, by using a one-electron model in size-selected N(2)O clusters. The one-electron model is composed of two nuclei and an extra electron moving in a two-dimensional plane including the two nuclei. The main purpose of this study is to explain the salient features of various dynamical processes of molecular ions in clusters using a simple theore ...
Reactions of the arene-linked bis(pyrazolyl)methane ligands m-bis[bis(1-pyrazolyl)methyl]benzene, (m-[CH(pz)2]2C6H4, Lm), p-bis[bis(1-pyrazolyl)methyl]benzene, (p-[CH(pz)2]2C6H4, Lp), and 1,3,5-tris[bis(1-pyrazolyl)methyl]benzene (1,3,5-[CH(pz)2]3C6H3, L3) with AgX salts (pz = 1-pyrazolyl; X = BF4- or PF6-) yield two types of molecular motifs depending on the arrangement of the ligating sites about the central arene ring. Reactions of the m-phenylene-linked Lm with AgBF4 and AgPF6 afford complex ...
The multidrug resistance (+associated) protein (MRP) is one of two ATP-dependent transport molecules which have been shown to be a cause of multidrug resistance in mammalian cells. The protein is ubiquitously expressed in human tissues and in a range of tumor types. In addition to a range of neutral or cationic cytotoxic drugs, MRP also transports heavy metals and organic anions including glutathione (GSH)-conjugates and glucuronate conjugates. In cells depleted of GSH, the activity of MRP towar ...
The kinetic properties of the chemical oxidation of aqueous polysulfide solutions have been studied in phosphate-buffered systems at pH 7-12, at temperatures between 20 and 40 degrees C, and ionic strength between 0.05 and 0.50 M. Polysulfide solutions were mixed with a buffer solution of known dissolved oxygen concentration, after which the decrease in the oxygen concentration of the solution was measured in time. The rate of oxygen consumption can be described by the empirical relation d[O2]/d ...
The thermally induced evolution mechanisms of various interactions in ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, bmimBF(4)) and water mixtures have been investigated in this paper. In the near-infrared (NIR) spectroscopy, we focus mainly on nu(OH) and nu(CH) overtone regions. During heating of bmimBF(4) and water mixtures, the nu(OH) overtone peak shows a significant blue shift, and the area of this peak shows different changes in three heating regions. By using the perturbati ...
Four heteroleptic copper(I) complexes containing phenanthroline and monoanionic nido-carborane-diphosphine ligands have been prepared and structurally characterized by various spectroscopic techniques and X-ray diffraction. These complexes exhibit intense absorptions in the visible range and excited-state lifetimes on the microsecond scale. Their application in visible-light-induced cross-dehydrogenative coupling reactions was investigated. Preliminary studies showed that one of the four copper( ...
The genome of the pathogenic bacterium Vibrio cholerae encodes for three carbonic anhydrases (CAs, EC 4.2.1.1) belonging to the α-, β- and γ-classes. Here we report and anion inhibition study of the β-CA, VchCAβ with anions and other small molecules which inhibit metalloenzymes. The best VchCAβ anion inhibitors were sulfamide, sulfamate, phenylboronic acid and phenylarsonic acid, which showed KIs in the range of 54-86μM. Diethyldithiocarbonate was also an effective VchCAβ inhibitor, with ...
Homogenization of hexadecane in water at pH 9 gives the same surface charge density in the presence of 0.2 mM thiocyanate or acetate anions as in the presence of chloride, indicating that these dipolar anions are not preferentially adsorbed at the oil/water interface. The decrease in the zeta potential of the emulsion droplets as the sodium salts of iodate, thiocyanate, or acetate are added from 0.1 to 10 mM is the same as that when sodium chloride is added, leading to the same conclusion. Incre ...
Complexation of copper(II) by calix[6]arene-based ligands bearing either two or three N-benzylimidazole coordinating arms under basic conditions has been studied. Whereas the tris(imidazole) derivative stabilizes dicationic 5-coordinate aqua complexes in a mononuclear state with an intracavity bound guest, in the presence of hydroxide ions, the latter undergo dimerization. An X-ray structure revealed decoordination of one imidazole arm and formation of a bis(hydroxo) bridged Cu(II) core with a s ...
Eukaryotic initiation factor 2-associated glycoprotein, p67, plays important roles in the regulation of eIF2alpha phosphorylation and thus maintains cell growth and proliferation. The p67 sequence can be divided into two segments, the N-terminal segment of amino acids 1-107 (p26) and the downstream segment of amino acids 108-480 (p52). Comparison of the amino acid sequences of p67 from lower to higher organisms suggests that there is a progressive addition of several unique domains at the N-term ...
Synthesis and structural characterization of an octanuclear Cu(I) cluster [Cu(8){Se(2)P(O(i)Pr)(2)}(6)](PF(6))(2) (1) with an empty Cu(8) cubic core involving diisopropyl diselenophosphate (dsep) ligand has been demonstrated despite its high tendency to abstract anions even from the traces of impurities in the solvent. Reaction of 1 with anion sources (Bu(4)NF for F(-); NaBH(4) for H(-), and NaSH for S(2-)) in a 1:1 ratio produced anion-centered Cu(8) clusters with a formula [Cu(8)(X){Se(2)P(O(i ...