Anions: Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.Anion Transport Proteins: Membrane proteins whose primary function is to facilitate the transport of negatively charged molecules (anions) across a biological membrane.Organic Anion Transporters: Proteins involved in the transport of organic anions. They play an important role in the elimination of a variety of endogenous substances, xenobiotics and their metabolites from the body.Organic Anion Transporters, Sodium-Independent: A subclass of ORGANIC ANION TRANSPORTERS that do not rely directly or indirectly upon sodium ion gradients for the transport of organic ions.Voltage-Dependent Anion Channels: A family of voltage-gated eukaryotic porins that form aqueous channels. They play an essential role in mitochondrial CELL MEMBRANE PERMEABILITY, are often regulated by BCL-2 PROTO-ONCOGENE PROTEINS, and have been implicated in APOPTOSIS.Voltage-Dependent Anion Channel 1: Voltage-dependent anion channel 1 is the major pore-forming protein of the mitochondrial outer membrane. It also functions as a ferricyanide reductase in the PLASMA MEMBRANE.Superoxides: Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to METHEMOGLOBIN. In living organisms, SUPEROXIDE DISMUTASE protects the cell from the deleterious effects of superoxides.Chlorides: Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.Anion Exchange Resins: High-molecular-weight insoluble polymers that contain functional cationic groups capable of undergoing exchange reactions with anions.Bromides: Salts of hydrobromic acid, HBr, with the bromine atom in the 1- oxidation state. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Voltage-Dependent Anion Channel 2: Voltage-dependent anion channel 2 is a low abundance mammalian isoform of VDAC that interacts with the inactive form of BAK PROTEIN.4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid: An inhibitor of anion conductance including band 3-mediated anion transport.p-Aminohippuric Acid: The glycine amide of 4-aminobenzoic acid. Its sodium salt is used as a diagnostic aid to measure effective renal plasma flow (ERPF) and excretory capacity.4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid: A non-penetrating amino reagent (commonly called SITS) which acts as an inhibitor of anion transport in erythrocytes and other cells.Bicarbonates: Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.SLC4A Proteins: Bicarbonate transporters that move BICARBONATE IONS in exchange of CHLORIDE IONS or SODIUM IONS across membranes. They regulate acid-base HOMEOSTASIS, cell volume and intracellular pH. Members include CHLORIDE-BICARBONATE ANTIPORTERS (SLC4A1, 2, 3, and 9); SODIUM-COUPLED BICARBONATE TRANSPORTERS (SLC4A4 and 5, 7, 8 and 10); and a sodium borate cotransporter (SLC4A11 protein).Sulfates: Inorganic salts of sulfuric acid.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Sulfobromophthalein: A phenolphthalein that is used as a diagnostic aid in hepatic function determination.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Probenecid: The prototypical uricosuric agent. It inhibits the renal excretion of organic anions and reduces tubular reabsorption of urate. Probenecid has also been used to treat patients with renal impairment, and, because it reduces the renal tubular excretion of other drugs, has been used as an adjunct to antibacterial therapy.Chloride Channels: Cell membrane glycoproteins that form channels to selectively pass chloride ions. Nonselective blockers include FENAMATES; ETHACRYNIC ACID; and TAMOXIFEN.Organic Anion Transport Polypeptide C: An organic anion transporter found in human liver. It is capable of transporting a variety organic anions and mediates sodium-independent uptake of bile in the liver.Kinetics: The rate dynamics in chemical or physical systems.Iodides: Inorganic binary compounds of iodine or the I- ion.Ion Channels: Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.Calixarenes: Phenolic metacyclophanes derived from condensation of PHENOLS and ALDEHYDES. The name derives from the vase-like molecular structures. A bracketed [n] indicates the number of aromatic rings.Ion Exchange: Reversible chemical reaction between a solid, often one of the ION EXCHANGE RESINS, and a fluid whereby ions may be exchanged from one substance to another. This technique is used in water purification, in research, and in industry.Thiocyanates: Organic derivatives of thiocyanic acid which contain the general formula R-SCN.Cations: Positively charged atoms, radicals or groups of atoms which travel to the cathode or negative pole during electrolysis.Superoxide Dismutase: An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC 1.15.1.1.Nitrates: Inorganic or organic salts and esters of nitric acid. These compounds contain the NO3- radical.Acid-Base Imbalance: Disturbances in the ACID-BASE EQUILIBRIUM of the body.Membrane Potentials: The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).Cell Membrane Permeability: A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.Acid-Base Equilibrium: The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance.Ions: An atom or group of atoms that have a positive or negative electric charge due to a gain (negative charge) or loss (positive charge) of one or more electrons. Atoms with a positive charge are known as CATIONS; those with a negative charge are ANIONS.Biological Transport, Active: The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.Carbonates: Salts or ions of the theoretical carbonic acid, containing the radical CO2(3-). Carbonates are readily decomposed by acids. The carbonates of the alkali metals are water-soluble; all others are insoluble. (From Grant & Hackh's Chemical Dictionary, 5th ed)Free Radicals: Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Sodium: A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.Estrone: An aromatized C18 steroid with a 3-hydroxyl group and a 17-ketone, a major mammalian estrogen. It is converted from ANDROSTENEDIONE directly, or from TESTOSTERONE via ESTRADIOL. In humans, it is produced primarily by the cyclic ovaries, PLACENTA, and the ADIPOSE TISSUE of men and postmenopausal women.Chromatography, Ion Exchange: Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.Hypotonic Solutions: Solutions that have a lesser osmotic pressure than a reference solution such as blood, plasma, or interstitial fluid.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Perchlorates: Compounds that contain the Cl(=O)(=O)(=O)O- structure. Included under this heading is perchloric acid and the salts and ester forms of perchlorate.Electric Conductivity: The ability of a substrate to allow the passage of ELECTRONS.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Oxalates: Derivatives of OXALIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are derived from the ethanedioic acid structure.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Phosphates: Inorganic salts of phosphoric acid.Xanthine Oxidase: An iron-molybdenum flavoprotein containing FLAVIN-ADENINE DINUCLEOTIDE that oxidizes hypoxanthine, some other purines and pterins, and aldehydes. Deficiency of the enzyme, an autosomal recessive trait, causes xanthinuria.Free Radical Scavengers: Substances that influence the course of a chemical reaction by ready combination with free radicals. Among other effects, this combining activity protects pancreatic islets against damage by cytokines and prevents myocardial and pulmonary perfusion injuries.Uricosuric Agents: Gout suppressants that act directly on the renal tubule to increase the excretion of uric acid, thus reducing its concentrations in plasma.Cystic Fibrosis Transmembrane Conductance Regulator: A chloride channel that regulates secretion in many exocrine tissues. Abnormalities in the CFTR gene have been shown to cause cystic fibrosis. (Hum Genet 1994;93(4):364-8)Taurocholic Acid: The product of conjugation of cholic acid with taurine. Its sodium salt is the chief ingredient of the bile of carnivorous animals. It acts as a detergent to solubilize fats for absorption and is itself absorbed. It is used as a cholagogue and cholerectic.Hydroxides: Inorganic compounds that contain the OH- group.Tetraphenylborate: An anionic compound that is used as a reagent for determination of potassium, ammonium, rubidium, and cesium ions. It also uncouples oxidative phosphorylation and forms complexes with biological materials, and is used in biological assays.Kidney: Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.Potassium: An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.NADPH Oxidase: A flavoprotein enzyme that catalyzes the univalent reduction of OXYGEN using NADPH as an electron donor to create SUPEROXIDE ANION. The enzyme is dependent on a variety of CYTOCHROMES. Defects in the production of superoxide ions by enzymes such as NADPH oxidase result in GRANULOMATOUS DISEASE, CHRONIC.Multidrug Resistance-Associated Proteins: A sequence-related subfamily of ATP-BINDING CASSETTE TRANSPORTERS that actively transport organic substrates. Although considered organic anion transporters, a subset of proteins in this family have also been shown to convey drug resistance to neutral organic drugs. Their cellular function may have clinical significance for CHEMOTHERAPY in that they transport a variety of ANTINEOPLASTIC AGENTS. Overexpression of proteins in this class by NEOPLASMS is considered a possible mechanism in the development of multidrug resistance (DRUG RESISTANCE, MULTIPLE). Although similar in function to P-GLYCOPROTEINS, the proteins in this class share little sequence homology to the p-glycoprotein family of proteins.Neutrophils: Granular leukocytes having a nucleus with three to five lobes connected by slender threads of chromatin, and cytoplasm containing fine inconspicuous granules and stainable by neutral dyes.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Adenosine Triphosphate: An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.Hydrogen Peroxide: A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.Carboxylic Acids: Organic compounds containing the carboxy group (-COOH). This group of compounds includes amino acids and fatty acids. Carboxylic acids can be saturated, unsaturated, or aromatic.Molecular Structure: The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.Organic Anion Transporters, Sodium-Dependent: A subclass of ORGANIC ANION TRANSPORTERS whose transport of organic anions is driven either directly or indirectly by a gradient of sodium ions.Xenopus laevis: The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.Osmolar Concentration: The concentration of osmotically active particles in solution expressed in terms of osmoles of solute per liter of solution. Osmolality is expressed in terms of osmoles of solute per kilogram of solvent.Phenolsulfonphthalein: Red dye, pH indicator, and diagnostic aid for determination of renal function. It is used also for studies of the gastrointestinal and other systems.Stilbenes: Organic compounds that contain 1,2-diphenylethylene as a functional group.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Kidney Tubules, Proximal: The renal tubule portion that extends from the BOWMAN CAPSULE in the KIDNEY CORTEX into the KIDNEY MEDULLA. The proximal tubule consists of a convoluted proximal segment in the cortex, and a distal straight segment descending into the medulla where it forms the U-shaped LOOP OF HENLE.Patch-Clamp Techniques: An electrophysiologic technique for studying cells, cell membranes, and occasionally isolated organelles. All patch-clamp methods rely on a very high-resistance seal between a micropipette and a membrane; the seal is usually attained by gentle suction. The four most common variants include on-cell patch, inside-out patch, outside-out patch, and whole-cell clamp. Patch-clamp methods are commonly used to voltage clamp, that is control the voltage across the membrane and measure current flow, but current-clamp methods, in which the current is controlled and the voltage is measured, are also used.Oocytes: Female germ cells derived from OOGONIA and termed OOCYTES when they enter MEIOSIS. The primary oocytes begin meiosis but are arrested at the diplotene state until OVULATION at PUBERTY to give rise to haploid secondary oocytes or ova (OVUM).

The stimulatory effects of Hofmeister ions on the activities of neuronal nitric-oxide synthase. Apparent substrate inhibition by l-arginine is overcome in the presence of protein-destabilizing agents. (1/2355)

A variety of monovalent anions and cations were effective in stimulating both calcium ion/calmodulin (Ca2+/CaM)-independent NADPH-cytochrome c reductase activity of, and Ca2+/CaM-dependent nitric oxide (NO.) synthesis by, neuronal nitric oxide synthase (nNOS). The efficacy of the ions in stimulating both activities could be correlated, in general, with their efficacy in precipitating or stabilizing certain proteins, an order referred to as the Hofmeister ion series. In the hemoglobin capture assay, used for measurement of NO. production, apparent substrate inhibition by L-arginine was almost completely reversed by the addition of sodium perchlorate (NaClO4), one of the more effective protein-destabilizing agents tested. Examination of this phenomenon by the assay of L-arginine conversion to L-citrulline revealed that the stimulatory effect of NaClO4 on the reaction was observed only in the presence of oxyhemoglobin or superoxide anion (generated by xanthine and xanthine oxidase), both scavengers of NO. Spectrophotometric examination of nNOS revealed that the addition of NaClO4 and a superoxide-generating system, but neither alone, prevented the increase of heme absorption at 436 nm, which has been attributed to the nitrosyl complex. The data are consistent with the release of autoinhibitory NO. coordinated to the prosthetic group of nNOS, which, in conjunction with an NO. scavenger, causes stimulation of the reaction.  (+info)

Reactivity of cyanate with valine-1 (alpha) of hemoglobin. A probe of conformational change and anion binding. (2/2355)

The 3-fold increase in the carbamylation rate of Val-1 (alpha) of hemoglobin upon deoxygenation described earlier is now shown to be a sensitive probe of conformational change. Thus, whereas this residue in methemoglobin A is carbamylated at the same rate as in liganded hemoglobin, upon addition of inositol hexaphosphate its carbamylation rate is enhanced 30% as much as the total change in the rate between the CO and deoxy states. For CO-hemoglobin Kansas in the presence of the organic phosphate, the relative increase in the carbamylation rate of this residue is about 50%. These results indicate that methemoglobin A and hemoglobin Kansas in the presence of inositol hexaphosphate do not assume a conformation identical with deoxyhemoglobin but rather form either a mixture of R and T states or an intermediate conformation in the region around Val-1 (alpha). Studies on the mechanism for the rate enhancement in deoxyhemoglobin suggest that the cyanate anion binds to groups in the vicinity of Val-1 (alpha) prior to proton transfer and carbamylation of this NH2-terminal residue. Thus, specific removal with carboxypeptidase B of Arg-141 (alpha), which is close to Val-1 (alpha) in deoxyhemoglobin, abolishes the enhancement in carbamylation. Chloride, which has the same valency as cyanate, is a better competitive inhibitor of the carbamylation of deoxyhemoglobin (Ki = 50 mM) compared with liganded hemoglobin. Nitrate and iodide are also effective inhibitors of the carbamylation of Val-1 (alpha) of deoxyhemoglobin (Ki = 35 mM); inorganic phosphate, sulfate, and fluoride are poor competitive inhibitors. The change in pKa of Val-1 (alpha) upon deoxygenation may be due to its differential interaction with chloride.  (+info)

Distinct sensitivities of OmpF and PhoE porins to charged modulators. (3/2355)

The inhibition of the anion-selective PhoE porin by ATP and of the cation-selective OmpF porin by polyamines has been previously documented. In the present study, we have extended the comparison of the inhibitor-porin pairs by investigating the effect of anions (ATP and aspartate) and positively charged polyamines (spermine and cadaverine) on both OmpF and PhoE with the patch-clamp technique, and by comparing directly the gating kinetics of the channels modulated by their respective substrates. The novel findings reported here are (1) that the activity of PhoE is completely unaffected by polyamines, and (2) that the kinetic changes induced by ATP on PhoE or polyamines on OmpF suggest different mechanisms of inhibition. ATP induces a high degree of flickering in the PhoE-mediated current and appears to behave as a blocker of ion flow during its presumed transport through PhoE. Polyamines modulate the kinetics of openings and closings of OmpF, in addition to promoting a blocker-like flickering activity. The strong correlation between sensitivity to inhibitors and ion selectivity suggests that some common molecular determinants are involved in these two properties and is in agreement with the hypothesis that polyamines bind inside the pore of cationic porins.  (+info)

Regulation of a volume-sensitive anion channel in rat pancreatic beta-cells by intracellular adenine nucleotides. (4/2355)

1. The patch-clamp technique in the whole-cell configuration was used to measure the effects of intracellular adenine nucleotides on activity of the volume-sensitive anion channel in single, isolated rat pancreatic beta-cells. 2. In the absence of intracellular nucleotides, swelling of cells with a hypertonic pipette solution failed to activate the conductance. Addition of ATP over the range 2-10 mM maintaining the same degree of hypertonicity caused a progressive activation of the conductance. An increase in ATP produced a similar activation of the conductance in non-swollen cells, albeit with reduced current amplitudes. 3. Activation of the conductance was also observed in the presence of ATPgammaS, adenylyl imidophosphate (AMP-PNP), ADP, diadenosine tetraphosphate and GTPgammaS. Neither ADP nor GDPbetaS inhibited activation of the conductance by ATP. 4. It is concluded that activity of the beta-cell volume-sensitive anion channel can be modulated by changes in intracellular concentrations of ATP within the physiological concentration range by a mechanism that does not require nucleotide hydrolysis. Activity of the channel does not appear to be modulated by a G protein-coupled mechanism.  (+info)

Phospholipid-subclass-specific partitioning of lipophilic ions in membrane-water systems. (5/2355)

Herein, we systematically investigate phospholipid-subclass-specific alterations in the partitioning of both cationic and anionic amphiphiles to identify the importance of ester, ether and vinyl ether linkages at the sn-1 position of phospholipids in the partitioning of charged amphiphiles. The results demonstrated that the membrane-water partition coefficient of a prototypic cationic amphiphile (i.e. 3,3'-dipropylthiadicarbocyanine iodide) was approximately 2.5 times higher in membranes comprised of plasmenylcholine in comparison with membranes comprised of either phosphatidylcholine or plasmanylcholine. In striking contrast, the membrane-water partition coefficient of a prototypic anionic amphiphile [i.e. bis-(1,3-dibutylbarbituric acid)trimethine oxonol] in membranes comprised of plasmenylcholine was approximately 2.5 times lower than that manifest in membranes comprised of phosphatidylcholine or plasmanylcholine. Utilizing theseexperimentally determined partition coefficients,the relative membrane dipole potential of membranes comprised of plasmenylcholine was calculated and found to be approximately 25 mV lower than in membranes comprised of phosphatidylcholine or plasmanylcholine. This lower membrane dipole potential in membranes comprised of plasmenylcholine is equivalent to the membrane potential induced by incorporation of approximately 25 mol% of anionic phospholipids in membranes comprised of phosphatidylcholine. Collectively, these results demonstrate that phospholipid-subclass-specific differences in the membrane dipole potential contribute to alterations in the partitioning of lipophilic ions in membrane bilayers comprised of distinct phospholipid subclasses. Moreover, they suggest that these physicochemical differences can be exploited to facilitate the targeting of charged lipophilic drugs to specific cells and subcellular membrane compartments.  (+info)

Evidence for an anion exchange mechanism for uptake of conjugated bile acid from the rat jejunum. (6/2355)

Absorption of conjugated bile acids from the small intestine is very efficient. The mechanisms of jejunal absorption are not very well understood. The aim of this study was to clarify the mechanism of absorption of conjugated bile acid at the apical membrane of jejunal epithelial cells. Brush-border membrane vesicles from intestinal epithelial cells of the rat were prepared. Absorption of two taurine-conjugated bile acids that are representative of endogenous bile acids in many variate vertebrate species were studied. In ileal, but not jejunal brush-border membrane vesicles, transport of conjugated bile acids was cis-stimulated by sodium. Transport of conjugated bile acids was trans-stimulated by bicarbonate in the jejunum. Absorption of conjugated dihydroxy-bile acids was almost twice as fast as of trihydroxy-bile acids. Coincubation with other conjugated bile acids, bromosulfophthalein, and DIDS, as well as by incubation in the cold inhibited the transport rate effectively. Absorption of conjugated bile acids in the jejunum from the rat is driven by anion exchange and is most likely an antiport transport.  (+info)

Anion efflux from cytotrophoblast cells derived from normal term human placenta is stimulated by hyposmotic challenge and extracellular A23187 but not by membrane-soluble cAMP. (7/2355)

The regulation of placental anion transport influences fetal accretion and placental homeostasis. We investigated whether efflux of 125I- or 36Cl- from multinucleated cytotrophoblast cells derived from human term placenta is regulated by one of three stimuli: (a) the calcium ionophore A23187, (b) a 'cocktail' of agents designed to raise intracellular levels of cAMP, (c) a hyposmotic solution. After loading with the appropriate isotope for 2 h and thorough washing, cells were exposed to sequential aliquots of buffer applied and removed each minute. Following an equilibration period of 5 min one of the stimuli was applied at room temperature At the end of the experiment the cells were lysed to give a lysate count which was used to express the count obtained from each aliquot as percentage efflux of that possible for that minute. The cAMP 'cocktail' and A23187 were applied for 5 min; the hyposmotic solution was applied for 10 min. The results for 125I- at 7 min showed that the mean efflux in the presence of hyposmotic shock was greater than control (5.7 +/- 1.0% min-1 versus 2.2 +/- 0.1% min-1, respectively; mean +/- S.E.M., n = 4 placentas). Similarly mean efflux at 6 min in the presence of A23187 was also significantly greater than control (6.5 +/- 1.9% min-1 versus 2.6 +/- 1.0% min-1, respectively, n = 3 placentas). The mean efflux in the presence of the cAMP cocktail was not different from control at any time point. The results were qualitatively the same if 36Cl- was used in the place of 125I- and when the experiment was performed with 36Cl- in a HCO3- buffer gassed with CO2. Mean 125I- efflux at 6 min in response to hyposmotic challenge was 33% less (P < 0.01) in the presence of 1 mM 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid (DIDS) and 37% less (P < 0.005) in the presence of 10 microM tamoxifen but no different if the hyposmotic solution was nominally calcium free. We conclude that there are differential effects of second messengers on anion efflux from the differentiated cytotrophoblast cells.  (+info)

Thermodynamic studies on anion binding to apotransferrin and to recombinant transferrin N-lobe half molecules. (8/2355)

Equilibrium constants for the binding of anions to apotransferrin, to the recombinant N-lobe half transferrin molecule (Tf/2N), and to a series of mutants of Tf/2N have been determined by difference UV titrations of samples in 0.1 M Hepes buffer at pH 7.4 and 25 degrees C. The anions included in this study are phosphate, sulfate, bicarbonate, pyrophosphate, methylenediphosphonic acid, and ethylenediphosphonic acid. There are no significant differences between anion binding to Tf/2N and anion binding to the N-lobe of apotransferrin. The binding of simple anions like phosphate appears to be essentially equivalent for the two apotransferrin binding sites. The binding of pyrophosphate and the diphosphonates is inequivalent, and the studies on the recombinant Tf/2N show that the stronger binding is associated with the N-terminal site. Anion binding constants for phosphate, pyrophosphate, and the diphosphonates with the N-lobe mutants K206A, K296A, and R124A have been determined. Anion binding tends to be weakest for the K296A mutant, but the variation in log K values among the three mutants is surprisingly small. It appears that the side chains of K206, K296, and R124 all make comparable contributions to anion binding. There are significant variations in the intensities of the peaks in the difference UV spectra that are generated by the titrations of the mutant apoproteins with these anions. These differences appear to be related more to variations in the molar extinction coefficients of the anion-protein complexes rather than to differences in binding constants.  (+info)

  • 5.1 Ion chromatography provides for both qualitative and quantitative determination of seven common anions, F − , Cl − , NO 2 − , HPO 4 −2 , Br − , NO 3 − , and SO 4 −2 , in the milligram per litre range from a single analytical operation requiring only a few millilitres of sample and taking approximately 10 to 15 min for completion. (astm.org)
  • 5.2 Anion combinations such as Cl − /Br − and NO 2 − /NO 3 − , which may be difficult to distinguish by other analytical methods, are readily separated by ion chromatography. (astm.org)
  • NOE enhancements in the presence of anions revealed that anion-receptor complexes favour the syn-syn conformation of the C2 and C7 substituents. (soton.ac.uk)
  • eng] Several sandwich complexes of hexafluorobenzene, trifluorobenzene, s-triazine, and trifluoro-s-triazine with halides, nitrate, and carbonate anions have been optimized at the RI-MP2/6-31++G** (full and frozen core), B3LYP/6-31++G**, and MPWB1K/6-31++G** levels of theory. (uib.es)
  • All possible combinations of the π-systems and anions (to generate the sandwich π anion π0 complexes) have been computed and analyzed using the aforementioned levels of theory. (uib.es)
  • This allows us to evaluate the reliability and the performance of the MPWB1K functional to compute the binding energies of the anion π complexes and to analyze the additivity of the interaction in π anion π0 complexes where the aromatic rings are of different nature (π-acidity). (uib.es)
  • 名倉葉 1990, ' Reaction of (η^1, η^2-But-3-En-1-YL) Tricarbonyliron (0) Anion Complexes with Carbon Electrophiles ', 中央研究院化學研究所集刊 , vol. 48, no. 37. (ntnu.edu.tw)
  • It is possible to predict whether an element will form a cation or anion by determining how many protons an element has. (reference.com)
  • When two elements are mixed, the amount of ionization energy determines whether the new substance will turn into a cation or anion. (reference.com)
  • When combining two elements, it is necessary to identify the atomic number of the elements to determine if the mix will result in a cation or anion. (reference.com)
  • The conformational preorganization and anion-induced conformational changes of indole-based receptors functionalized with an amide group at the 2-position and a variety of amide, urea and thiourea moieties at the 7-position have been studied by the means of NMR spectroscopy. (soton.ac.uk)
  • NOE experiments showed that anti-anti orientation across C2-C2 and C7-N7 bonds is preferred for receptors 1-4 in acetone solution in the absence of anions. (soton.ac.uk)
  • Anions such as low molecular weight organic acids (formate, acetate, propionate, etc.) that are conductive coelute with fluoride and would bias fluoride quantitation in some drinking waters and most wastewaters. (astm.org)
  • 1.6 Using alternate separator column and eluents may permit additional anions such as acetate, formate, or citrate to be determined. (astm.org)
  • Acetate anions also interact strongly with indole and urea NH donor groups, whereas nitrate anions interact solely with H7 and H7 urea/thiourea protons. (soton.ac.uk)
  • In 2,7-bis-carboxamido functionalized indoles the interaction with chloride and bromide anions primarily occurs at the indole H1 proton. (soton.ac.uk)
  • Discussion.Discussion.SLC26A3 and congenital chloride diarrhoea (Pia Hö glund).Discussion.Expression, regulation and the role of SLC26 Cl-/HCO3- exchangers in kidney and gastrointestinal tract (Manoocher Soleimani).Discussion.Anion exchangers in flux: functional differences between human and mouse SLC26A6 polypeptides (Seth L. Alper, Andrew K. Stewart, Marina N. Chernova,Alexander S. Zolotarev, Jeffrey S. Clark and David H. Vandorpe). (find-more-books.com)
  • Interaction of prestin (SLC26A5) with monovalent intracellular anions (Dominik Oliver, Thorsten Schä chinger and Bernd Fakler).Discussion. (find-more-books.com)
  • Herein, a pathway is presented for the multifold increase of the practical discharge power of these batteries by tailoring the tripartite interactions between the salt cation and anion and the solvent. (pnas.org)
  • Tetracholorodecaoxygen anion acts by killing bacteria and increasing the oxygen supply to the affected site thereby stimulating wound healing. (1mg.com)
  • Shaped like shallow bowls, the molecules have a strong affinity for binding with large anions such as certain borate, chlorate and phosphate ions. (innovations-report.com)
  • 1. A collection of particles comprising a crystalline composition with a phosphate anion, the collection of particles having an average particle size less than about 1000 nm. (freepatentsonline.com)
  • This application note shows the determination of phosphate, HEDP (etidronic acid) and pyrophosphate in a biocide sample using anion chromatography with conductivity detection after sequential suppression. (selectscience.net)
  • Also, anions are among the most pervasive of all known pollutants (e.g., nitrate, phosphate). (utexas.edu)
  • concentrations of the nitrile anion must be high to mitigate processes involving self-condensation, such as the Thorpe-Ziegler reaction. (wikipedia.org)
  • Plasmid DNA remains tightly bound to the DEAE groups over a wide range of salt concentrations (see figure Separation of nucleic acids at neutral pH on QIAGEN anion-exchange resin ). (qiagen.com)
  • In contrast, conventional anion-exchangers, based on cellulose, dextran, or agarose, have separation ranges only up to 0.4 M salt, so that binding and elution of all substances is limited to a narrow range of salt concentrations. (qiagen.com)
  • 1.4 Concentrations as low as 0.01 mg/L were determined depending upon the anions to be quantified, in single laboratory work. (astm.org)
  • A physical association of AE and carbonic anhydrase II (CAII) might explain how local HCO 3 - concentrations on the luminal side of the apical membrane can reach levels satisfying the thermodynamical conditions necessary for anion exchange. (biologists.org)
  • Electrochemical potential for the apical anion exchange (AE) process calculated assuming intracellular Cl - concentration and apical membrane potential of 30 mmol l -1 and -100 mV, respectively, and using luminal Cl - and HCO 3 - concentrations from unfed gulf toadfish ( Taylor and Grosell, 2006a ) and different intracellular HCO 3 - concentrations ranging from 1.5 to 40 mmol l -1 (indicated by different symbols). (biologists.org)
  • It is now being recognized that intestinal anion exchange is responsible for high luminal HCO 3 - and CO 3 2- concentrations while at the same time contributing substantially to intestinal Cl - and thereby water absorption, which is vital for marine fish osmoregulation. (biologists.org)
  • This webinar will cover monitoring of anion concentrations in flowback and produced waters generated from fracking processes. (acs.org)
  • We will present on the typical constituents reported for Marcellus Shale fracking operations as well as measurements of anion concentrations in water from impoundments used for recycling. (acs.org)
  • Since the Cation and Anion resin capacities are in Na and Cl meq/l respectively, I converted the feed water anionic and cationic concentrations from ppm CaCO3 to meq/L. (eng-tips.com)
  • Concentrations of nitrite, as low as 100 nmol/L, induced a significant increase in PgR mRNA, suggesting that physiologically and environmentally relevant doses of the anion activate ERα. (aacrjournals.org)
  • Protein involved in the exchange of anions across a membrane. (uniprot.org)
  • Despite an obvious cholesterol elevation, most excretory kidney functions, including organic anion excretion rate, are not influenced by the free cholesterol accumulation in proximal tubule cells, whereas some reabsorptive functions such as protein endocytosis and glucose reabsorption by the apical membrane appear to be vulnerable. (thefreedictionary.com)
  • When at least one group is CH.sub.2N(CH.sub.3).sub.3Br, the material functions as an anion exchange membrane. (osti.gov)
  • The composition can be used as anion-exchange membranes and as an electrode binder material in anion exchange membrane fuel cells. (osti.gov)
  • With a goal of developing a new anion exchange membrane technology with applications to fuel cells, electrolyzers, flow batteries and other energy conversion devices, they will evaluate new concepts in anion exchange membranes with low-cost polymer backbones and novel cations. (eurekalert.org)
  • Method and apparatus for analysis, by ion chromatography, of anions, in a sample solution, wherein accurate analysis of anions in the sample solution is obtained by passing carbonic acid, through a prescribed membrane, into the sample solution, thereby completely eliminating or sharply lessening the so-called water dip effect. (patentgenius.com)
  • The method and apparatus are further directed to enabling anions in the sample solution to be accurately analyzed by passing prescribed cations, through a prescribed membrane, into the sample solution, thereby depriving the sample solution of interfering anions otherwise abundantly present therein. (patentgenius.com)
  • The recent development and market introduction of a new type of alkaline stable imidazole-based anion exchange membrane and related ionomers by Dioxide Materials is enabling the advancement of new and improved electrochemical processes which can operate at commercially viable operating voltages, current efficiencies, and current densities. (frontiersin.org)
  • The first process is the direct electrochemical generation of pure formic acid in a three-compartment cell configuration using the alkaline stable anion exchange membrane and a cation exchange membrane. (frontiersin.org)
  • The CO 2 cell consists of a two-compartment design utilizing the alkaline stable anion exchange membrane to separate the anode and cathode compartments. (frontiersin.org)
  • The third process is an alkaline water electrolysis cell process, where the alkaline stable anion exchange membrane allows stable cell operation in 1 M KOH electrolyte solutions at current densities of 1 A/cm 2 at about 1.90 V. The cell has demonstrated operation for thousands of hours, showing a voltage increase in time of only 5 μV/h. (frontiersin.org)
  • In this paper, we discuss the detailed technical aspects of these three technologies utilizing this unique anion exchange membrane. (frontiersin.org)
  • 3) Electron-poor aromatic compounds undergo nucleophilic aromatic substitution in the presence of nitrile anions. (wikipedia.org)
  • Electron transfer dissociation of peptide anions. (nih.gov)
  • Ion/ion reactions of multiply deprotonated peptide anions with xenon radical cations result in electron abstraction to generate charge-reduced peptide anions containing a free-radical site. (nih.gov)
  • Electron anions (center green blob) pair up in the center of molecular cages and lower the temperature at which glass forms in C12A7 electride. (flickr.com)
  • The pyrenylboronic acid derivatives showed fluorescence quenching or enhancement due to photoinduced electron transfer originating from anion binding. (frontiersin.org)
  • One-electron oxidation of the anions yields the corresponding radicals. (google.com)
  • Multiply-charged anions derived from electrospray (ES) ionization of the oligonucleotide 5'-d(GTCTTAGCGCTAAGAC)-3' have been subjected to electron transfer reactions with ionized xenon in a quadrupole ion trap and found to undergo minimal fragmentation. (rti.org)
  • This observation stands in contrast with electron transfer to rare gases from anions of smaller oligonucleotides which have been shown to undergo extensive fragmentation. (rti.org)
  • The present results are attributed to longer anion lifetimes for the larger oligonucleotide anions (following highly exothermic electron transfer) which then allow for collisional cooling by the helium bath gas. (rti.org)
  • Transition metal anions come with electron configurations ( n +1)s 2 n d 10 ( n +1)p 0 , ( n +1)s 2 n d 10 ( n +1)p 1 , and ( n +1)s 2 n d 10 ( n +1)p 2 . (wiley.com)
  • In new work, researchers show how C12A7 components called electron anions help to transform crystalline C12A7 into semiconducting glass. (phys.org)
  • They suspected components of the electride known as electron anions were responsible. (phys.org)
  • Electron anions are essentially freely moving electrons in place of the much-larger negatively charged oxygen atoms that urge the oxide to form a tidy crystal. (phys.org)
  • The team simulated Hosono's lab experiments using molecular dynamics software that could capture the movement of both the atoms and the electron anions in both the melted material and glass. (phys.org)
  • The team found that that the negatively-charged electron anions paired up between positively charged aluminum or calcium atoms, replacing the negatively charged oxygen atoms that would typically be found between the metals. (phys.org)
  • The bonds that the electron anions formed between the metal atoms were weaker than bonds between metal and oxygen atoms. (phys.org)
  • This movement allowed a small number of electron anions to have a greater effect on the glass transition temperature than much larger quantities of minerals typically used as additives in glasses. (phys.org)
  • Low cost, durable, commercially viable polymer-based anion exchange membranes are the focus of a $2,300,000 grant from the U.S. Department of Energy to an industry, government, university collaboration including Penn State. (eurekalert.org)
  • This important university, industry, government lab collaboration has the potential to move the field forward in new anion exchange membranes," said Hickner. (eurekalert.org)
  • Some of the most elegant examples come from Kubik and co-workers who have developed a new class of anion receptor based on cyclic peptide subunits. (rsc.org)
  • Herein, a pathway is presented for the multifold increase of the practical discharge power of these batteries by tailoring the tripartite interactions between the salt cation and anion and the solvent. (pnas.org)
  • I am trying to develop a spreadsheet that will calculate the service time of both cation and anion exchangers based on the feed water quality. (eng-tips.com)
  • When it reacts with the I 3 - anion, the nitrite ion reduces itself to nitric oxide. (wikibooks.org)
  • To determine whether nitrite or nitrate was the active anion, diphenyleneiodonium was used to inhibit oxidation/reduction reactions in the cell. (aacrjournals.org)
  • The ability of diphenyleneiodonium to block the effects of nitrate, but not nitrite, on the induction of PgR mRNA and the activation of exogenously expressed ERα suggests that nitrite is the active anion. (aacrjournals.org)
  • Nitrite activated the chimeric receptor Gal-ER containing the DNA-binding domain of GAL-4 and the ligand-binding domain of ERα and blocked the binding of estradiol to the receptor, suggesting that the anion activates ERα through the ligand-binding domain. (aacrjournals.org)
  • Thus, the separation and purification qualities of QIAGEN resin, as well as its ease of use surpass those of conventional anion-exchange resins. (qiagen.com)
  • This invention relates to resins suitable for the removal of anions from fluid media and to processes of purifying fluid media by means of such resins. (freepatentsonline.com)
  • Batch decolorization experiments were conducted with the crude filtered vancomycin broth by adding 1g (based on dry weight) of various anion exchange resins to 20mL of broth, and shaking the contents for four hours. (thefreedictionary.com)
  • QIAGEN-tips contain a unique, patented anion-exchange resin which eliminates the need for expensive equipment and reagents such as ultracentrifuges, HPLC/FPLC‚ or CsCl. (qiagen.com)
  • The key advantage of QIAGEN anion-exchange resin arises from its exceptionally high charge density. (qiagen.com)
  • The separation range of QIAGEN resin is extremely broad, extending from 0.1 M to 1.6 M salt (see figure Separation of nucleic acids at neutral pH on QIAGEN anion-exchange resin ), and DNA can be efficiently separated from RNA and other impurities. (qiagen.com)
  • SDS and other anionic detergents interfere with the binding of nucleic acids to QIAGEN resin by competing for binding to the anion-exchange groups. (qiagen.com)
  • An improved chromatographic analytical column, the column containing a pellicular type (agglomerated) anion-exchange packing, comprising: Component A, which comprises a pressure packed bed of substrate particles of insoluble synthetic resin, having cation-exchanging sites at least on their available. (google.com)
  • Still another object of the present invention is to prepare an anion active resin from epichlorohydrin and a polyamine. (freepatentsonline.com)
  • The second object is attained by contacting a fluid containing anions with an insoluble resin prepared in the manner described above. (freepatentsonline.com)
  • The inorganic P extracted with anion exchange resin ([Pi. (thefreedictionary.com)
  • 2. Anion resin in the Cl- form will only remove nitrates. (eng-tips.com)
  • Organic anion transporters play important roles in the elimination of a variety of endogenous substances, xenobiotics and their metabolites from the body. (nih.gov)
  • OATs are multispecific organic anion transporters, the substrates of which include both endogenous (e.g. cyclic nucleotides, prostaglandins, urate, dicarboxylates) and exogenous anions (various anionic drugs and environmental substances). (nih.gov)
  • The OAT family represents the renal secretory pathway for organic anions and is also involved in the distribution of organic anions in the body. (nih.gov)
  • The realisation that very simple organic compounds can function as selective and effective anion receptor systems has led to work on studying the ability of simple off-the-shelf compounds such as catechol , 16 and of a wide range of commercially available compounds containing NH and OH hydrogen bond donor groups, 19 as selective anion sensors. (rsc.org)
  • It facilitates the efflux of organic anions including monoanionic bile acid and anti-cancer reagents such as etoposide and paclitaxel from liver and small intestine into blood (4-7). (cellsignal.com)
  • A mathematic approximation of the difference between unmeasured anions (PO4-, SO4-, proteins and organic acids) and unmeasured cations (Ca2+, Mg2+), with the former usually exceeding the latter. (thefreedictionary.com)
  • This chapter will discuss the efforts of our group and our collaborators in the areas of recognition and sensing of anionic species and of the roles of anions in assembly processes in solut ion and in the solid state. (springer.com)
  • Effective design has allowed neutral hydrogen bond donor receptor species to bind anions in aqueous solution, so overcoming the enthalpic penalty that must be paid to dehydrate even the most strongly hydrated anionic guest prior to complexation. (rsc.org)
  • The amphoteric metals of groups VB ( vanadium , niobium , and tantalum ) and VIB ( chromium , molybdenum , and tungsten ) in the +5 and +6 oxidation states, respectively, form weak acids that readily condense (polymerize) to form anions containing several molecules of the acid anhydride . (britannica.com)
  • A tricarboxylic acid anion obtained by deprotonation of at least one of the carboxy groups of citric acid. (ebi.ac.uk)
  • A carboxylic acid anion formed when the carboxy group of a monocarboxylic acid is deprotonated. (ebi.ac.uk)
  • Measured standard BE level was significantly less as compared to unmeasured anion effect on BE, in both the groups.Simplified Fencl-Stewart equation is effective in identifying a mixed acid-base disorder, which otherwise would remain undetected. (tripdatabase.com)
  • The reaction below indicates that the addition of an acid (HA, where H + is combined with an unmeasured anion A - ) results in the consumption of HCO 3 - with an addition of anions that will account for the increase in the AG. (medscape.com)
  • Clinical utility of anion gap in deciphering acid-base disorders. (medscape.com)
  • The separated anions in their acid form are measured using an electrical-conductivity cell. (emsl.com)
  • An anion gap blood test is a way to check the levels of acid in your blood. (medlineplus.gov)
  • Your health care provider may have ordered an anion gap blood test if you have signs of an imbalance in your blood acid levels. (medlineplus.gov)
  • The anion gap blood test can provide important information about the acid and base balance in your blood. (medlineplus.gov)
  • The serum anion gap in the evaluation of acid-base disorders: What are its limitations and can its effectiveness be improved? (medlineplus.gov)
  • Activity is inhibited by 4,4'-Di-isothiocyanatostilbene-2,2'-disulfonic acid (DIDS - an inhibitor of several anion channels and transporters). (uniprot.org)
  • A novel fluorescence chemosensor array composed of pyrenylboronic acid-based probes for multi- anion detection has been developed. (frontiersin.org)
  • However, to the best of our knowledge, general methods to distinguish the multiple anions simultaneously using simple boronic acid-based chemosensors have not been established owing to the complex interference among analytes. (frontiersin.org)
  • The anion exchange activity in vivo is likely most pronounced in the anterior segment and results in net intestinal acid absorption. (biologists.org)
  • A high anion gap means you have more acid in your blood than normal. (verywellhealth.com)
  • A low anion gap means you have a lower amount of acid in your blood than normal, but this result is uncommon and usually due to a lab error. (verywellhealth.com)
  • I started my work with the synthesis of ZnO nanostructures focusing on the effect of different anions of zinc salts on the morphology and crystallinity of ZnO nanostructures. (diva-portal.org)
  • A novel anion concept of pseudo-delocalized anions, anions with distinct positive and negative charge regions, has been studied by a computer aided synthesis using DFT calculations. (chalmers.se)
  • Supramolecular Chemistry of Anions , A. Bianchi, K. Bowman-James, and E. García-España Eds. (springer.com)
  • Except in the case of the very few of them that have been prepared by classical reactions of aqueous chemistry, such as K 2 H 5 (PO 4 )(P 2 O 7 ) and K 2 H 8 (PO 4 )2(P 2 O 7 ), there are no rules for the chemical preparation of these mixed-anion phosphates. (springer.com)
  • I want to get the latest chemistry news from C&EN in my inbox every week. (acs.org)
  • The field of anion receptor chemistry initiated in the late 1960s by Shriver and Biallas 1 and by Park and Simmons 2 was slow to develop in the subsequent two decades. (rsc.org)
  • The invention relates to the field of chemistry, and in particular to substituted and derivatized polyhedral borate and carborate anions and radicals useful in a variety of applications, for example, as weakly nucleophilic anions and/or as oxidizing agents. (google.com)
  • We observed that the medium containing zinc nitrate anions yields the nanorods, in a medium containing zinc acetate anions nano-candles are obtained. (diva-portal.org)
  • In contrast, decreased free radical scavenging properties of the vasculature in prolonged hyperglycemia and in later stages of diabetes might promote NO degradation by an overshoot of superoxide anions, resulting in an attenuation of endothelium-dependent vasodilation. (nih.gov)
  • 1.6 Using alternate separator column and eluents may permit additional anions such as acetate, formate, or citrate to be determined. (astm.org)
  • measured and used to derive [HCO3(-)], BE, anion gap (AG), AG adjusted for albumin (AGadj), strong ion difference, strong ion gap (SIG) and SIG corrected for water excess /deficit (SIGcor). (tripdatabase.com)
  • The anion gap is the difference between the sum of the most abundant measured serum anions (Cl-- and HCO3-) and serum cations (Na+, K+). (thefreedictionary.com)
  • Substituted borate and carborate anions having unusual properties of being exceptionally weakly nucleophilic and being soluble in non-polar solvents. (google.com)
  • There has been a consistent effort to develop anions that are very weakly nucleophilic. (google.com)
  • None of the known weakly nucleophilic anions meet these criteria. (google.com)
  • Among the known anions displaying some of the above properties, certain deltahedral closo-carborate anions (CB 11 H 12 1- ) have been shown to be both weakly coordinating and weakly nucleophilic (Reed, C. A. et al. (google.com)
  • There is also described (a) anion-exchangers having high breakthrough capacities, (b) a screening method and (c) a desalting protocol. (google.com)
  • Handbook of Anion Determination is a guidebook that details various methods that can be employed in determining anions. (worldcat.org)
  • To provide an analytical method for the quantitative determination of perchlorate anion in fruits, vegetables, milk, low moisture foods, infant foods, and water. (fda.gov)
  • Use a strong anion-exchange column with the Thermo Scientific™ DNASwift™ SAX-1S Oligonucleotide Column that provides exceptionally high resolution for the purification of oligonucleotides. (fishersci.com)
  • Exchange reactions of anions, especially ferrocyanide and carbonate, with layered double hydroxides (LDHs) were investigated in relation to the origin of life on the early Earth. (unt.edu)
  • Two parallel systems, the Na + , Cl - and the Na + ,K + ,2Cl - cotransporters account for Na + , K + and a portion of Cl - absorption, with the remaining Cl - uptake occurring via anion exchange (AE). (biologists.org)
  • The basolateral H + extrusion is critical for the apical anion exchange and relies on the Na + gradient established by the Na + -K + -ATPase. (biologists.org)
  • Anion exchange may also be used chromatographically, to separate anions, and, medicinally, to remove an anion (for example, Cl - ) from gastric contents or bile acids in the intestine. (thefreedictionary.com)
  • Anion exchange may also be used chromatographically, to separate anions, and medicinally, to remove an anion (e.g. (thefreedictionary.com)
  • Throughout specific ranges of pH and other conditions, most solutions of heteropolymolybdates and heteropolytungstates appear to contain predominantly one distinct species of anion, many of which are remarkably stable and nonlabile. (britannica.com)
  • A single protonable residue, a histidine, plays a key role by tran-siently protonating the transported anion to allow an uncharged species to pass the hydrophobic barrier. (biomedsearch.com)
  • Anions are important species in the natural world and are critically involved in almost the full range of known chemical process. (utexas.edu)
  • The compound's anion-sequestering abilities could find applications in environmental remediation of perchlorate and molecular sensing of biological phosphates. (acs.org)
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