High Concentrations Of Sodium Ions Research Articles

Effect of Exogenous Fatty Acids on the Cellular Fatty Acid Composition and Neomycin Formation in a Mutant Strain of Streptomyces fradiae

A mutant of Streptomyces fradiae which requires oleic acid for neomycin formation was isolated and the effects of exogenous fatty acids and other additives on the formation of neomycin were studied. Palmitic acid and high concentration of sodium ions could replace oleic acid in neomycin formation. The fatty acid spectrum of the mutant strain ST–5B was quite different from that of the parent strain 3123. The major fatty acid components of the mutant and the parent were anteiso 15:0 and iso 16: 0, respectively. However the fatty acid composition of the mutant was changed from the anteiso 15: 0-type to the parental iso 16: 0-type by the supplement of oleic acid or high concentration of sodium ions in the medium. In the case of palmitic acid, the major fatty acid component of the mutant cells was changed from anteriso 15: 0 to normal 16:0. The role of these additives in neomycin formation by the mutant is discussed.

The effect of salt on protein synthesis in the halophyte Suaeda maritima

An amino acid-incorporating microsomal fraction has been isolated from the leaves of the halophyte Suaeda maritima and the characteristics of the incorporation described. There were no differences in the properties of the microsomes isolated from plants grown in saline and non-saline conditions. The incorporation was severely inhibited by high concentrations of sodium or potassium ions. The results are discussed in relation to the mechanism of salt tolerance in halophytes and the localization of salt in the cells.

The composition of the haemolymph of the New Zealand earwig, Anisolabis littorea

The haemolymph of the maritime earwig, Anisolabis littorea, has been analysed for inorganic and organic components. The inorganic fraction has a high sodium ion concentration and osmotic pressure but a relatively lower chloride ion concentration. The organic fraction has a high amino acid content—the principal ones being proline, alanine, glutamic acid, and glutamine, and tyrosine. In contrast to the high aminoacidemia there is a very low carbohydrate content and no detectable trehalose in the haemolymph. The evolution of the composition of insect blood is discussed.

Activation by Adenosine Triphosphate in the Phosphorylation Kinetics of Sodium and Potassium Ion Transport Adenosine Triphosphatase

The steady state kinetics of sodium and potassium ion transport adenosine triphosphatase (EC 3.6.1.3) suggests an activating action of adenosine triphosphate in addition to its action as a phosphate donor. This action might be an acceleration of dissociation of K+ or its congeners from the enzyme. To test this possibility transient kinetics of the phosphoenzyme was investigated. In membranes from guinea pig kidney the enzyme was phosphorylated in the presence of magnesium ion and sodium ion with adenosine triphosphate which was radioactive in the terminal phosphate group. To this phosphoenzyme were added congeners of potassium ion, namely, rubidium ion or lithium ion at concentrations which produced an equal acceleration of dephosphorylation. At these same concentrations in the steady state, the level of dephosphoenzyme was higher in the presence of rubidium ion than in the presence of lithium ion. Rephosphorylation was relatively inhibited in the presence of rubidium ion. Rubidium ion appeared to combine with the phosphoenzyme, split off the phosphate group, and remain with the dephosphoenzyme in a relatively stable complex. This complex was isolated kinetically by addition of a high concentration of sodium ion with oligomycin. The isolated complex was less stable following an increase in the concentration of adenosine triphosphate. It was concluded that adenosine triphosphate was activating the enzyme in a fashion functionally distinct from its action as a phosphate donor, since adenosine triphosphate does not phosphorylate the enzyme in the presence of rubidium ion without sodium ion and since the concentration of adenosine triphosphate required for activation was much higher than that required for phosphorylation. The relatively stable complex of rubidium ion with the dephosphoenzyme was interpreted as evidence for a closed or occluded conformation of the active site for translocation of potassium ion across the membrane. Toxic agents altered this complex of the dephosphoenzyme; phlorizin increased and tetraphenyl boron decreased its stability. This kinetic mechanism provides an interpretation for a paradoxical feature in the p-nitrophenyl phosphatase activity of this enzyme system.

The molecular mechanism of cardiac glycoside action

The sequence of events leading to cardiac muscle contraction is: (1) passive diffusion of sodium ions intracellularly and potassium ions extracellularly ( depolarization), (2) release of bound calcium ions from the sarcoplasmic reticulum, (3) formation of a calcium-troponin-tropomyosin complex which frees acceptor sites on actin for interaction with the cross-bridges on myosin, (4) myosin ATPase induces the interaction of actin and myosin thereby causing a contraction, (5) active pumping mechanism—“sodium pump”—for the cellular removal of sodium ions and the cellular reentry of potassium ions by cell membrane ATPase ( repolarization occurs during this process), and (6) active pumping of calcium ions from the actomyosin complex—followed by muscle relaxation. Cardiac glycosides interfere with the sequence of events leading to cardiac muscle contraction by inhibiting cell membrane ATPase (“sodium pump”). This results in: (1) a high intracellular sodium ion concentration, (2) the prevention of the intracellular influx of potassium ions, and (3) an apparent increase in the “free” intracellular calcium ion concentration thereby causing a net increase in myocardial contraction through the interaction of calcium ions and the contractile proteins.

The role of sodium in promoting ventricular arrhythmia during selective coronary arteriography.

Conclusions have been drawn in past experimentation that myocardial toxicity of contrast media during selective cardiac vessel studies is related to high sodium ion concentration and/or the prophylactic effect of methylglucamine salts.This paper evaluates the incidence of cardiac arrhythmias during human and canine selective coronary arteriography using 2 formulations of renografin 76 per cent which have sodium concentrations of approximately 0.19 mEq./ml. and 0.04 mEq./ml.Five marked ventricular arrhythmias associated with contrast agent were noted in 79 selective coronary artery injections in 30 patients for an incidence of 6.3 per cent. Only one of these—a transient asystole— followed the use of an agent with the higher sodium content. Nineteen randomized selective coronary arteriography studies in dogs produced 9 cases of ventricular fibrillation.All fibrillations occurred during right coronary artery injection, and all but 1 occurred while using the agent with the lower sodium content. Thus, a purer ...

The effect of enzymatic depolymerization of arterial mucopolysaccharides on sodium ion content and vessel reactivity.

1. The presence of mucopolysaccharides within arterial walls may be associated with the high concentration of sodium ions within this tissue. These polyanions are sensitive to enzymatic depolymerization which results in a loss of the cation binding properties of the molecule. 2. In this study testicular hyaluronidase perfused through isolated arterial segments resulted in a decrease in reactivity of the artery to 65% that of control arteries. Associated with this finding was a 33% decrease in the sodium ion content of the stimulated hyaluronidase-treated artery. When a variety of other sympathetically innervated tissues were treated with hyaluronidase there was no decrease in reactivity or sodium ion content.

Synaptic potentials recorded by the sucrose-gap method from the rabbit superior cervical ganglion.

1. Compound ganglionic potentials evoked by stimulation of the preganglionic nerves to the superior cervical ganglion of the rabbit were recorded by the sucrose-gap method.2. When the distal part of the ganglion was bathed in flowing isotonic sucrose solution or sodium-deficient solutions, ganglionic action potentials were no longer evoked, only large synaptic potentials.3. The compound synaptic potential, which remained unaltered for more than 1 h, originated in a population of cells at the interface between the Krebs and sucrose solutions. Hexamethonium reduced the size but did not alter the time course of the synaptic potential.4. It is suggested that a higher concentration of sodium ions is required for the generation of ganglionic action potentials than for either conduction in the postganglionic axons or production of synaptic potentials.5. When lithium replaced sodium in the solution bathing the distal part of the ganglion, the synaptic potential was greatly reduced in amplitude. Impulse propagation in the postganglionic axons was only slightly impaired when lithium replaced sodium in the solution bathing the axons.6. A quantitative assessment of the potency of the ganglion-blocking drugs nicotine, pentolinium, hexamethonium and pempidine was made by measuring the depression of the synaptic potentials produced by bathing the distal part of the ganglion in flowing isotonic sucrose solution. The concentrations which produced a 50% depression were 8.1 muM nicotine, 26.5 muM pentolinium, 111 muM hexamethonium and 22.2 muM pempidine.

A study of the cell envelope of the halobacteria.

SUMMARY: Electron microscopy on thin sections of three different extremely halophilic Halobacterium species showed that their cell envelopes were of similar general construction: an inner membrane and an outer layer. The outer layer stains most strongly in the outermost part. When the NaCl concentration of the environment was lowered from the optimal of 4·3 m to 2·2 m the outer layer of the cell envelope of Halobacterium salinarium strain 1 became frayed; in many cells a release of material from the outer layer appeared to take place. When the cells were exposed to distilled water the outer layer of the envelope appeared to dissolve completely and the cell membrane disintegrated into tiny flakes. Fragments of the cell envelope produced by mechanical disintegration of the cells in 4·3 m-NaCl formed closed vesicles very rapidly; some of the cytoplasmic material became trapped inside the vesicles. Detergents appeared to slow down the closing of the vesicles and also to cause a release of material from the outer layer of the cell envelope. The cell envelope vesicles were mainly composed of protein and lipid; their content of amino sugar was low compared with the cell envelope of other Gram-negative bacteria. The cell envelope vesicle also contained nucleic acids; most of these were probably parts of the cytoplasmic material trapped inside the vesicles. The amino acid composition showed that the protein of the cell envelope vesicles was quite acidic, consistent with the contention that high concentrations of sodium ions stabilize the cell envelopes of these organisms by neutralizing the negative charges of the protein. Upon centrifugation at high speed of the lysate obtained by dialysis of the cell envelope vesicles against distilled water, the fragments of the cell membrane sedimented whereas most of the protein, presumably from the outer layer of the cell envelope, stayed in the supernatant fraction. Carotenoids and cytochromes were contained in the sediment with the membrane fragments. Most of the amino sugar-containing components stayed in the supernatant fraction; in the presence of 10–25 m salt most of the amino sugar-containing components sediment with the membrane fragments.

Inhibition of respiration in submitochondrial particles by N,N'-dicyclohexylcarbodiimide: the effect of sodium, potassium, and antibiotics which alter membrane permeability.

NADH oxidation catalyzed by submitochondrial particles produced by sonic treatment (ETPH) is inhibited by N,N′-dicyclohexylcarbodiimide. The inhibition of electron-transfer activity is released by uncouplers of oxidative phosphorylation, but not by ADP nor by potassium or sodium ions, either in the presence or absence of valinomycin or tyrocidin. Low concentrations of potassium or sodium (0–30 mM) either in the presence or absence of valinomycin or tyrocidin do not significantly increase the rate of NADH oxidation by ETPH. High concentrations of sodium or potassium ions (30–120 mM) cause a significant increase in the rate of NADH oxidation by ETPH. It is suggested that the metal ion transport system is a property of the oriented inner mitochondrial membrane, and that high concentrations of metal ion are required to overcome the low permeability of the ETPH membrane in the inward direction in order to transport the metal ion actively in the outward direction.

Electric fields at the surface and interface of SiO 2 films on silicon

At solid surfaces and interfaces the potential energy of electrons has a sharp discontinuity with respect to the adjacent bulk phases. This change of potential give rise to parallel opposing layers of charged defects or ions within insulating or semiconducting solids. The concentration of charge and the electric field depend not only on the interfacial potential drop, but also on the potential and concentration of electron donor or acceptor sites in the interfacial region. At the surface of thin silicon oxide films grown on silicon, oxide ions provide a layer of negative charge; an equal positive charge (usually sodium ions) is concentrated in the oxide within about 200 Å of the surface. A similar double layer develops at the interface with silicon, where electrons donated to the silicon provide a negative charge having an adjacent positive charge layer in the oxide. Both positive charge layers exhibit a Poisson-Boltzmann distribution, with a potential drop at the surface always about three times greater than at the interface. Sodium oxide impurities are the dominant electron-donors; these supply the electrons for the negative surface and interfacial layers (as well as for any competing electron-acceptor sites). A high density of acceptor sites can be introduced into silicon dioxide by conditions tending to produce oxygen vacancies, and when the electrons from sodium oxide donors are trapped by such acceptor sites the sodium ions are localized near the trapped electrons. Under these conditions few electrons and sodium ions reach the surface or interface. Since a high surface density of oxide ions requires a high concentration of sodium ions, it is not surprising that the rate of oxidation of silicon increases with sodium content.

Axonal function and ionic regulation in the central nervous system of a phytophagous insect (Carausius morosus).

ABSTRACT Experiments using intracellular and extracellular recording techniques indicate that, despite the specialized ionic composition of the haemolymph, the axons in the nerve cord of Carausius are conventional in that the action current is largely carried by sodium ions. This effect is achieved by an appreciable regulation of the concentrations of inorganic ions in the extracellular fluid bathing the axon surfaces. The extra-axonal regulation does not appear to result from any significant restriction in the accessibility of cations to the general extracellular system, but from a local regulation which appears to maintain a relatively high concentration of sodium ions at the axon surfaces. It is suggested that such a regulation may be achieved by an extrusion of sodium ions from the glial cells into the restricted extra-axonal spaces demonstrated in the electron micrographs of this preparation.

Effect of novocain on electrical activity of a single node of ranvier in solutions with high and low sodium ion concentrations

Effect of novocain on electrical activity of a single node of ranvier in solutions with high and low sodium ion concentrations

Inhibition of choline acetyltransferase by excess cysteine.

THE first demonstrations of an enzyme that would synthesize acetylcholine (ACh)—originally designated choline acetylase but now called choline acetyltransferase (acetyl-CoA: choline-O-acetyltransferase, EC 2.3.1.6.)—depended on the presence in the tissues of other endogenous enzymes which would synthesize acetyl-CoA. Even when the substrate role of acetyl-CoA had been appreciated, however, it was found that in order to realize the maximal activity of the enzyme, provision had to be made to couple it with another enzyme system which would produce acetyl-CoA continuously from suitable precursors. Compared with the production from such coupled systems the amount of ACh produced from added synthetic acetyl-CoA was as little as 20 per cent in the experiments of Reisberg1 and about 50 per cent in those of Smallman2 and of Morris and Tucek3. However, McCaman and Hunt4 have obtained proportionately much higher yields of ACh in a buffer-substrate system containing synthetic acetyl-CoA, choline, eserine, magnesium sulphate, bovine plasma albumin and a high concentration of sodium chloride. Their incubations were conducted at pH 7.4. These authors considered that their higher yields of ACh depended on the replacement of potassium with a high concentration of sodium ions, but it appears that other factors may be more important.

The ribosomes of the extremely halophilic bacterium, Halobacterium cutirubrum

The ribosomes of Halobacterium cutirubrum, a micro-organism that grows in saturated sodium chloride and probably has an internal concentration of potassium chloride near saturation, exist as 70 s particles when isolated in saturated potassium chloride containing 0·1 M -magnesium chloride at pH 7. These particles are stable in concentrations of magnesium ions as high as 0·4 M . If the potassium ion concentration is below about 4 M , or the magnesium ion concentration below 0·1 M , the ribosomes dissociate into 52 s and 31 s subunits. The requirement by the 70 s particles for potassium ions is specific; in high concentrations of ammonium or caesium ions, many of the ribosomes dissociate into subunits, while in high concentrations of sodium ions, they dissociate and aggregate in a complex way. About 53% of the RNA of the cell is accounted for by the ribosomes, which consist of 60% RNA and 40% protein. The estimated molecular weights of the ribosome and its subunits are in the ratio 3 : 2 : 1. At low concentrations of magnesium ions in the absence of potassium ions, the ribosomes lose low molecular weight RNA and up to 75% of their protein, to produce a labile 42 s component and more stable 33 s and 22 s particles, which contain about 80% RNA. It is suggested that the 42 s, 33 s and 22 s components, with molecular weights in the ratio 3 : 2 : 1, represent essentially the RNA moieties of the whole 70 s ribosome and of the 52 s and 31 s subunits respectively, together with some structural protein. Gel electrophoresis showed that the proteins which are lost are acidic. It is concluded that in these ribosomes, the stability of the ribonucleoprotein depends on potassium ions which shield negative groups, and on magnesium ions, which provide ionic cross-links between RNA and protein.

On the Structural Transformations and Lysis of Halobacterium salinarium in Hypotonic and Isotonic Solution s

SUMMARY When the NaCl concentration of a suspension of Halobacterium salinarium is gradually lowered by adding water, the rod-shaped organisms are converted to spheres which lyse. The organisms do not change in size when transformed from rods to spheres. Chemicals which do not possess a strong net charge in aqueous solutions do not protect the structure of the organism when they replace NaCl in iso-osmolar concentions. The rod shape of the organisms is only maintained by very high concentrations of ions which interact weakly with common proteins; lithium and ammonium ions are exceptions to this rule. Ions which display strong interactions with common proteins, and chemicals which are believed to break secondary bonds between protein molecules, effect a transformation of rods to spheres, and frequently a lysis of the spheres, when brought in contact with organisms suspended in strong NaCl solution. The changes in structure in hypotonic and isotonic solutions are not affected by metabolic inhibitors. Isolated cell-wall fragments disintegrate into smaller units when exposed to conditions under which whole organisms lyse. It is concluded that the structural transformations and lysis of H. salinarium in hypotonic solutions are not caused by the action of enzymes and that osmotic phenomena play no, or only a minor, role. The observations support the contention that the globular lipoprotein particles, which constitute the bulk of the material of the cell wall of these bacteria, are bound together mainly by electrostatic forces and secondary bonds. When the cells are exposed to hypotonic solutions, or to ions which bind strongly to proteins, or to chemicals which are believed to break secondary bonds between protein molecules, the linkages binding the lipoprotein particles together are weakened so that the wall structure disintegrates. Only in the presence of high concentrations of sodium and chloride ions, or other ions which bind loosely to proteins, is it possible for the proteinaceous particles of the cell wall to associate in an orderly array.

The metabolism of pyruvic oxime by extracts of Tetrahymena pyriformis S

An enzyme capable of hydrolyzing pyruvic oxime to hydroxylamine and pyruvic acid has been purified 14-fold from extracts of the ciliated protozoan, Tetrahymena pyriformis. The enzyme also hydrolyzes α-ketoglutaric oxime at all stages of purification. Activity toward pyruvic oxime is inhibited by small amounts of zinc, cobaltous and ferric ions, as well as by azide. High concentrations of potassium, magnesium, and calcium ions are also inhibitory. Enzymic activity is unaffected by high concentrations of sodium or cuprous ions, or by iodoacetate or p-chloromercuriphenylsulfonic acid. The enzyme shows optimal activity over the pH range 6.1–7.8.

An ion exchange method of determining carnosine, anserine and their precursors in animal tissue.

ALTHOUGH elegant procedures have been described for the separation of the neutral and acidic amino-acids by elution from sulphonated polystyrene resins, the quantitative separation of the basic amino-acids has proved more difficult1,2. For example, when the pH of the eluting buffer is more than 7 their recoveries rarely exceed 80 per cent. It is for this reason that buffers of pH less than 7 and relatively high sodium ion concentration have previously been used in their separation, although such conditions greatly reduce the sensitivity of the method.

Geochemistry and Migration of Meteoric and Connate Waters as Related to Geologic Structure: ABSTRACT

Data obtained during geologic and geochemical studies in several areas of the Sacramento Valley have suggested correlation between subsurface structure and the occurrence of a type of saline water in the shallow water-bearing deposits. Sufficient data have been collected to permit construction of subsurface contours on the base of fresh water. These contours, which reflect general structure in the Sacramento-San Joaquin Delta area, represent the interface between fresh water and a specific type of saline water. This connate water contains high concentrations of sodium and chloride ions, low concentrations of sulphate and nitrate ions, and approximately equal concentrations of iodide and bromide. Under hydrodynamic conditions, fresh water in the foothills with considerable head has apparently flushed the saline waters out of a part of the marine sediments. In the Delta area this connate water has been forced upward from the marine sediments to the surface along faults and from truncated marine sediments on anticlinal structures. There are numerous other ground-water anomalies which may indicate the presence of buried structural features. A characteristic type of water apparently associated with faulting may be noted in the shallow water-bearing deposits. This water commonly has higher temperatures and greater concentrations of silica and boron than the normal ground water. Further geochemical studies of this type may be of value to the petroleum industry. End_of_Article - Last_Page 431------------

A Method for Predicting the Tendency of Oil Field Waters to Deposit Calcium Sulfate

Abstract A graphic method was developed which can be used to predict the tendency of oil field waters to precipitate calcium sulfate under a variety of conditions. Application of this method is made to the prediction of sulfate scale formation in heater treaters, boilers, oil wells, cooling systems and water injection wells. Introduction A solution may be said to be in equilibrium with respect to a given salt when the concentration of that salt is equal to its solubility. If for any reason the concentration of the salt is increased or its solubility decreased, the equilibrium is upset and precipitation of the salt takes place. Thus, if the concentration of a salt in a particular solution is known and its solubility can be calculated for a given set of conditions, the tendency of this salt to form a precipitate under these conditions can be predicted. Based on these principles a method has been developed for determining the tendency of oil field waters to form calcium sulfate precipitates under various conditions. The Solubility Diagram Calcium sulfate precipitation most frequently occurs when two waters are mixed; one containing calcium ions, and the other sulfate ions. As one of these waters is added to the other a point may be reached where the concentration of calcium sulfate is greater than its solubility, thus causing the formation of a precipitate. The solubility diagram is a graphic device for determining the location of such points, thereby making possible a prediction of the tendency of such a system to deposit sulfate scale. A similar diagram can be used to solve many other problems involving the precipitation of calcium sulfate. Fig. 1 shows a solubility diagram representing the mixing of two waters. Water "A" contains a high concentration of sodium, magnesium, and sulfate ions together with a small amount of calcium. Water "B" contains a high concentration of calcium ions together with sodium, magnesium and a small amount of sulfate ions.