scholarly journals The Biological Action of Ions and the Concentration of Ions at Surfaces

1944 ◽  
Vol 20 (2) ◽  
pp. 167-176
Author(s):  
J. F. DANIELLI
Keyword(s):  
Complex Formation ◽  
Cell Surface ◽  
Sea Water ◽  
Biological Action ◽  
Mass Action ◽  
Colloidal Iron ◽  
Electrode Potentials ◽  
Concentration Of Ions ◽  
The Individual ◽  
Environmental Fluid

1. It is pointed out that at the surface of a cell the absolute concentration of ions, and the ratios of the concentrations of the individual ions, are usually different from the corresponding quantities in the environmental fluid. It is suggested that the necessity for a Na:Ca ratio of the order of 50:1 in a physiologically balanced fluid is found because such a ratio in the environmental fluid produces a Na:Ca ratio of the order of unity at the cell surface. 2. The concentrations of calcium and sodium ions at the surface of ovalbumin molecules are calculated. It is shown that calcium is bound (a) by electrostatic forces, (b) by formation of apparently unionized complexes with carboxyl groups. The complex formation obeys the law of mass action. 3. The ratio, total Na:total Ca at the surface of various cells in physiological media is calculated from the electrokinetic potentials of the cells. The calculated ratio is of the order of unity. In two cases calculation of the maximum possible total Ca at the cell surface by two other independent methods gives values of the same order of magnitude as the calculation from electrokinetic potentials. 4. It is shown that, where the toxic action of ions is due to complex formation with anions present at a surface, the logarithms of the equitoxic concentrations of the metals should be a linear function of the standard electrode potentials of the metals. 5. Calculations show that the concentration of colloidal Fe at the surface of organisms in sea-water should be far greater than the concentration in the environment: it is suggested that marine plants derive their iron from this layer of adsorbed colloidal iron. 6. A mechanism is suggested which provides for intense adsorption of drugs at specific surfaces.

Anion effect on alkali ion-crown complex formation in a moderately concentrated solutions: A sensitive probe of hidden interionic interactions operating in dissociating protic solvents

1990 ◽  
Vol 55 (5) ◽  
pp. 1149-1161
Author(s):  
Jiří Závada ◽  
Václav Pechanec ◽  
Oldřich Kocián
Keyword(s):  
Hydrogen Bond ◽  
Complex Formation ◽  
Charge Density ◽  
Macrocyclic Ligand ◽  
Simple Explanation ◽  
Anion Effect ◽  
Protic Solvents ◽  
The Individual ◽  
Alkali Salts ◽  
Alkali Ion

A powerful anion effect destabilizing alkali ion-crown complex formation has been found to operate in moderately concentrated protic (H2O, CH3OH, C2H5OH) solution, following the order HO- > AcO- > Cl- > Br- > NO3- > I- > NCS-. Evidence is provided that the observed effect does not originate from ion-pairing. A simple explanation is provided in terms of concordant hydrogen bond bridges of exalted stability between the gegenions, M+···OR-H···(OR-H)n···OR-H···A-. It is proposed that encapsulation of alkali ion by the macrocyclic ligand leads to a dissipation of the cation charge density destroying its ability to participate in the hydrogen bond bridge. An opposition against the alkali ion-crown complex formation arises accordingly in the solution in dependence on strength of the hydrogen bridge; for a given cation, the hydrogen bond strength increases with increasing anion charge density from NCS- to HO-(RO-). It is pointed out, at the same time, that the observed anion effect does not correlate with the known values of activity coefficients of the individual alkali salts which are almost insensitive to anion variation under the investigated conditions. As a resolution of the apparent paradoxon it is proposed that, in absence of the macrocyclic ligand, the stabilizing (concordant) bonding between the gegenions is nearly balanced by a destabilizing (discordant) hydrogen bonding between the ions of same charge (co-ions). Intrinsic differences among the individual salts are thus submerged in protic solvents and become apparent only when the concordant bonding is suppressed in the alkali ion-crown complex formation.

scholarly journals Specific Binding of Rubidium in Chlorella

1962 ◽  
Vol 45 (5) ◽  
pp. 959-977 ◽  
Author(s):  
Dan Cohen
Keyword(s):  
Active Transport ◽  
Binding Sites ◽  
Specific Binding ◽  
High Concentration ◽  
External Concentration ◽  
Specific Binding Sites ◽  
Dense Suspension ◽  
Concentration Of Ions ◽  
The Individual ◽  
A Site

Specific binding sites for potassium, which may be components of the carriers for active transport for K in Chlorella, were characterized by their capacity to bind rubidium. A dense suspension was allowed to take up Rb86 from a low concentration of Rb86 and a high concentration of ions which saturate non-specific sites. The amount bound was derived from the increase in the external concentration of Rb86 following addition of excess potassium. The sites were heterogeneous. The average affinity of Rb and various other ions for the sites was determined by plotting the degree of displacement of Rb86 against log molar concentration of the individual ions. Interpolation gave the concentration for 50 per cent displacement of Rb, which is inversely related to affinity. The order of affinity was not changed when the cells were frozen, or boiled either in water or in 70 per cent ethanol. The affinity is maximal for ions with a crystalline radius of 1.3 to 1.5 A and a high polarizability, and is not related to the hydrated radius or valency. It is suggested that binding groups in a site are rigidly arranged, the irregular space between them being 2.6 to 3.0 A across, so that affinity is high for ions of this diameter and high polarizability.

Localization and expression of msp130, a primary mesenchyme lineage-specific cell surface protein in the sea urchin embryo

Development ◽  
1987 ◽  
Vol 101 (2) ◽  
pp. 255-265 ◽  
Author(s):  
J.A. Anstrom ◽  
J.E. Chin ◽  
D.S. Leaf ◽  
A.L. Parks ◽  
R.A. Raff
Keyword(s):  
Cell Surface ◽  
Sea Urchin ◽  
Sea Water ◽  
Surface Protein ◽  
Specific Cell ◽  
Cell Surface Protein ◽  
Sea Urchin Embryo ◽  
A Cell ◽  
Mesenchyme Cells ◽  
Primary Mesenchyme Cells

In this report, we use a monoclonal antibody (B2C2) and antibodies against a fusion protein (Leaf et al. 1987) to characterize msp130, a cell surface protein specific to the primary mesenchyme cells of the sea urchin embryo. This protein first appears on the surface of these cells upon ingression into the blastocoel. Immunoelectronmicroscopy shows that msp130 is present in the trans side of the Golgi apparatus and on the extracellular surface of primary mesenchyme cells. Four precursor proteins to msp130 are identified and we show that B2C2 recognizes only the mature form of msp130. We demonstrate that msp130 contains N-linked carbohydrate groups and that the B2C2 epitope is sensitive to endoglycosidase F digestion. Evidence that msp130 is apparently a sulphated glycoprotein is presented. The recognition of the B2C2 epitope of msp130 is disrupted when embryos are cultured in sulphate-free sea water. In addition, two-dimensional immunoblots show that msp130 is an acidic protein that becomes substantially less acidic in the absence of sulphate. We also show that two other independently derived monoclonal antibodies, IG8 (McClay et al. 1983; McClay, Matranga & Wessel, 1985) and 1223 (Carson et al. 1985), recognize msp130, and suggest this protein to be a major cell surface antigen of primary mesenchyme cells.

scholarly journals Thermodynamic Aspects of Homeopathy

2020 ◽  
Author(s):  
Mihael Drofenik
Keyword(s):  
Thermodynamic Model ◽  
Healthy Person ◽  
Mass Action ◽  
Molecular Crowding ◽  
Science And Art ◽  
Healthy State ◽  
The Law ◽  
Definition Of ◽  
The Individual ◽  
Necessary And Sufficient

The well-known definition of disease, which Samuel Hahnemann presented in a tentative theory for his new science and art of healing, is used as the starting point for the thermodynamic model of homeopathy. The Le Chatelier principle was applied to the biochemical equilibrium compartmentalized in the individual human cells of an ill person to explain the curing based on the re-establishment of the starting equilibrium of a healthy person when using a remedy. It is revealed that a high dilution accompanied by succession is required to release the remedies to their constituent molecular species in order to increase their activity when taking part in the biochemical equilibrium that is essential for healing. In addition, a single remedy reaction-product species, when it is in excess, as well as satisfying the kinetic equilibrium, is a necessary and sufficient condition to force the new biochemical equilibrium in the direction of the basic original equilibrium associated with a healthy state. In addition, homeopathic aggravation is considered on the basis of the Law of Mass Action and the role of the small remedy concentration in some high-profile models is revisited. The second elementary law of homeopathy, the Law of the Infinitesimals, was explained based on a kinetic model. When a remedy occurs in the human cell of a healthy person and forms a reaction product (Simillimum) that induces the finest medical symptoms of an ill person, then remedies entering the cell of the ill person will form identical Simillimum molecules and re-establish the initial equilibrium of the healthy state and cure the ill person. However, this will also induce a molecular crowding in the cells of the ill person. For kinetic reasons, this will aggravate the re-establishment of the initial equilibrium and consequently worsen or even interrupt the medical treatment. At a low remedy concentration, the molecular crowding becomes negligible while the formation of the Simillimum and the re-establishment of the initial equilibrium will take place continuously and cure the person who is ill. The final understanding of the Simillimum in the thermodynamic model was illuminated and wide-opened its duality with the ill person’s key compound.

scholarly journals Glycosaminoglycans on fibroblasts accelerate thrombin inhibition by protease nexin-1

1987 ◽  
Vol 245 (2) ◽  
pp. 543-550 ◽  
Author(s):  
D H Farrell ◽  
D D Cunningham
Keyword(s):  
Complex Formation ◽  
Cell Surface ◽  
Plasma Membranes ◽  
Chondroitin Sulphate ◽  
Human Fibroblasts ◽  
Heparan Sulphate ◽  
Order Rate Constant ◽  
Subsequent Treatment ◽  
Protease Nexin ◽  
Inhibition Of Thrombin

Protease nexin-1 (PN-1) is a proteinase inhibitor that is secreted by human fibroblasts in culture. PN-1 inhibits certain regulatory serine proteinases by forming a covalent complex with the catalytic-site serine residue; the complex then binds to the cell surface and is internalized and degraded. The fibroblast surface was recently shown to accelerate the rate of complex-formation between PN-1 and thrombin. The present paper demonstrates that the accelerative activity is primarily due to cell-surface heparan sulphate, with a much smaller contribution from chondroitin sulphate. This conclusion is supported by the effects of purified glycosaminoglycans on the second-order rate constant for the inhibition of thrombin by PN-1. Also, treatment of 35SO4(2-)-labelled cells with heparitin sulphate lyase or chondroitin sulphate ABC lyase demonstrated two discrete pools of 35S-labelled glycosaminoglycans; subsequent treatment of plasma membranes with these glycosidases showed that heparitin sulphate lyase treatment abolished about 80% of the accelerative activity and chondroitin sulphate ABC lyase removed the remaining 20%. These results show that two components are responsible for the acceleration of PN-1-thrombin complex-formation by human fibroblasts. Although dermatan sulphate is also present on fibroblasts, it did not accelerate the inhibition of thrombin by PN-1.

The Mechanical Properties of the Cell Surface

1955 ◽  
Vol 32 (4) ◽  
pp. 734-750 ◽  
Author(s):  
J. M. MITCHISON ◽  
M. M. SWANN
Keyword(s):  
Cell Surface ◽  
Young’S Modulus ◽  
Sea Water ◽  
Young's Modulus ◽  
Contractile Ring ◽  
A Value ◽  
Sudden Rise ◽  
Slow Rise ◽  
Stage Yield ◽  
Sperm Aster

1. Measurements with the cell elastimeter on the stiffness of the cell membrane of fertilized sea-urchin eggs show the following general features. There is a sudden rise at fertilization, followed by a fall during the early sperm aster stage to the lowest value reached during development (a Young's modulus of about 0.58 x 104 dynes/cm.2). The stiffness rises slowly until metaphase, after which it rises rapidly to reach a maximum during late anaphase and early cleavage (6.81 x 104 dynes/cm.2). During the later stages of cleavage the stiffness falls again and reaches a value in the second interphase which is about twice as high as in the first interphase. Masurements on naked eggs in calcium-free sea water indicate that the slow rise in metaphase is due to the development of the hyaline layer. 2. Measurements on swollen and shrunken eggs at cleavage indicate that there is no interal pressure in the eggs at this stage, but similar experiments with eggs at the sperm aster stage yield anomalous results. Observations on the wrinkling point in shrunken eggs show that the maximum possible internal pressure is 19 dynes/cm.2 for sperm aster eggs and 500 dynes/cm.2 for cleaving eggs. 3. The bearing of these results on various theories of the mechanism of cleavage is briefly discussed. The rise in Young's modulus of the whole cell surface at cleavage argues against theories depending on the action of the spindle and asters, and against theories proposing a contractile ring in the surface. The rise is, however, what might be expected on the basis of the expanding membrane theory.

scholarly journals THE PHYSIOLOGY OF THE RESPIRATION OF FISHES IN RELATION TO THE HYDROGEN ION CONCENTRATION OF THE MEDIUM

1922 ◽  
Vol 4 (3) ◽  
pp. 305-317 ◽  
Author(s):  
Edwin B. Powers
Keyword(s):  
Optimum Condition ◽  
Sea Water ◽  
Close Correlation ◽  
Marine Fishes ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Alkaline Reserve ◽  
The Individual ◽  
Low Tension

1. The ability of marine fishes to absorb oxygen at low tension from the sea water is more or less dependent upon the hydrogen ion concentration of the water. 2. The ability of fishes to withstand wide variations in the range of hydrogen ion concentration of the sea water can be correlated with their habitats. The fishes that are most resistant to a wide variation in the hydrogen ion concentration are most cosmopolitan in their habitat. Those that are least resistant to a variation in the hydrogen ion concentration are the most restricted in their range of habitat. 3. There is a close correlation between the optimum condition of the sea water for the absorption of oxygen at low tension by the herring (Clupea pallasii), the condition of the sea water to which they react positive and that in which they are found most abundantly. 4. It is suggested that the variation in the ability to absorb oxygen at low tension at a given pH of individuals of a species is dependent upon the alkaline reserve of the blood of the individual fish.

scholarly journals Identification of the integrin-binding site on coagulation factor VIIa required for proangiogenic PAR2 signaling

Blood ◽  
2018 ◽  
Vol 131 (6) ◽  
pp. 674-685 ◽  
Author(s):  
Andrea S. Rothmeier ◽  
Enbo Liu ◽  
Sagarika Chakrabarty ◽  
Jennifer Disse ◽  
Barbara M. Mueller ◽  
...  
Keyword(s):  
Complex Formation ◽  
Cell Surface ◽  
Binding Site ◽  
Factor Viia ◽  
Coagulation Factor ◽  
Binding Motif ◽  
Integrin Β1 ◽  
Key Points ◽  
Integrin Binding Site ◽  
Recycling Pathway

Key Points The FVIIa integrin-binding motif is required for TF-FVIIa complex formation with integrin β1 and proangiogenic signaling. The arf6 integrin recycling pathway controls TF-FVIIa signaling and cell surface availability for procoagulant activity.

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