Volume changes for mixing the major sea salts: Equations valid to ionic strength 3.0 and temperature 95�C

1989 ◽  
Vol 18 (11) ◽  
pp. 1007-1017 ◽  
Author(s):  
Leslie M. Connaughton ◽  
Frank J. Millero ◽  
Kenneth S. Pitzer
Keyword(s):  
Ionic Strength ◽  
Volume Changes ◽  
Sea Salts

PVT properties of concentrated aqueous electrolytes. III. Volume changes for mixing the major sea salts at I=1.0 and 3.0 at 25�C

1985 ◽  
Vol 14 (12) ◽  
pp. 837-851 ◽  
Author(s):  
Frank J. Millero ◽  
Leslie M. Connaughton ◽  
Faina Vinokurova ◽  
Peter V. Chetirkin
Keyword(s):  
Aqueous Electrolytes ◽  
Pvt Properties ◽  
Volume Changes ◽  
Sea Salts

scholarly journals THE VARIATION IN THE STRUCTURE OF ERYTHROCYTE NUCLEI WITH FIXATION

1962 ◽  
Vol 14 (3) ◽  
pp. 445-458 ◽  
Author(s):  
Howard G. Davies ◽  
Michael Spencer
Keyword(s):  
Electron Microscope ◽  
Ionic Strength ◽  
Divalent Cation ◽  
Volume Change ◽  
Chromatin Structure ◽  
Molecular Interaction ◽  
Calcium Ion ◽  
Volume Changes ◽  
Charged Macromolecules

Observations have been made on the role of a divalent cation (calcium ion) during OsO4 fixation of nuclei of frog erythrocytes, mainly after isolation from cells. The volume of the nucleus depends partly on the molecular interaction of charged macromolecules, is controlled by the ionic strength of the medium, and hence may be used as a guide in attempts to preserve structure. When the isolation and fixation media contain 0.01 M calcium at pH 6.3 the volume changes, in the light microscope, during processing are small. When the fixative does not contain these ions, reversible volume changes occur during fixation and dehydration. The chromatin of nuclei processed with minimal volume change appears, in the electron microscope, to contain fine dots and lines about 20 to 40 A in diameter, relatively close together. The chromatin structure of nuclei in which volume changes have occurred consists of dense irregularly shaped patches, relatively far apart, and ranging in diameter from about 200 A down to the limits of visibility (20 to 30 A). It is suggested that the latter structure is a precipitation artefact.

Influence of extracellular media’s ionic strength on the osmotic stability of Sahel goat erythrocytes

2015 ◽  
Vol 26 (2) ◽  
Author(s):  
Nanacha Afifi Igbokwe ◽  
Ikechukwu Onyebuchi Igbokwe
Keyword(s):  
Ionic Strength ◽  
Osmotic Fragility ◽  
Ionic Concentration ◽  
Fragility Curve ◽  
Osmotic Resistance ◽  
Volume Changes ◽  
Erythrocyte Osmotic Fragility ◽  
Osmotic Stability ◽  
Osmotic Lysis ◽  
Sahel Goat

AbstractHeparinised blood was exposed to osmotic lysis in hypotonic buffered saline to evaluate erythrocyte membrane stability. When KThe erythrocyte osmotic fragility curve in saline was hyperbolic even when the ionic concentration was reduced by 50% with saccharides. Haemolysis was higher with EDTA than heparinised blood at saline concentrations of 90 and 150–180 mosmol/L. The fragility curve was sigmoidal and shifted to the left when saline was completely substituted with a saccharide. The non-ionic saccharides increased erythrocyte osmotic resistance linearly (r=0.88; p<0.02) from median to minimal hyposmolarities (150–300 mosmol/L) and reduced the osmolyte concentration at median fragility by 36%. No effect occurred at <30–120 mosmol/L and >90% fragility; and saccharide concentrations were almost non-lytic at comparable saline concentrations evoking <10% haemolysis. Fragilities were neither affected by period (30–60 min) of incubation nor the type of saccharide used.In this study, the variation in osmotic stability of caprine erythrocytes was linked to ionic strength of the suspending extracellular media which seemed to exert an influence through transmembrane ion fluxes and regulatory volume changes in erythrocytes.

Sea cucumber mimicking bacterial cellulose composite hydrogel with ionic strength-sensitive mechanical adaptivity

2018 ◽  
Vol 54 (80) ◽  
pp. 11320-11323 ◽  
Author(s):  
Chen Qian ◽  
Taka-Aki Asoh ◽  
Hiroshi Uyama
Keyword(s):  
Ionic Strength ◽  
Bacterial Cellulose ◽  
Sea Cucumber ◽  
Composite Hydrogel ◽  
Volume Changes ◽  
Significant Volume ◽  
Cellulose Composite

A novel sea cucumber-mimicking bacterial cellulose composite hydrogel shows stiffness changes in response to ionic strength without significant volume changes.

Swelling activation of transport pathways in erythrocytes: effects of Cl−, ionic strength, and volume changes

1999 ◽  
Vol 276 (1) ◽  
pp. C210-C220 ◽  
Author(s):  
Hélène Guizouarn ◽  
René Motais
Keyword(s):  
Ionic Strength ◽  
External Medium ◽  
Ionic Composition ◽  
Volume Changes ◽  
Salt Accumulation ◽  
Transport Pathways ◽  
Large Loss ◽  
A Cell ◽  
Negative Modulator ◽  
Broad Specificity

If swelling of a cell is induced by a decrease in external medium tonicity, the regulatory response is more complex than if swelling of similar magnitude is due to salt uptake. The present results provide an explanation. In fish erythrocytes, two distinct transport pathways were swelling activated: a channel of broad specificity and a K+-Cl−cotransporter. Each was activated by a specific signal: the channel by a decrease in intracellular ionic strength and the K+-Cl−cotransporter by cell enlargement. A decrease in ionic strength also affected K+-Cl−cotransport activity, but by acting as a negative modulator of the cotransport. Thus cells swollen by salt accumulation respond by activating exclusively the K+-Cl−cotransport, leading to a Cl−-dependent K+ loss. By contrast, cells swollen by electrolyte dilution respond by activating both pathways, leading to a reduced loss of electrolytes and a large loss of taurine. Thus two swelling-sensitive pathways, differently regulated, would allow control of the ionic composition of a cell exposed to different volume perturbations.

Effect of shape-volume changes on uptake of CO and O2 by hemoglobin in erythrocytes

1963 ◽  
Vol 18 (1) ◽  
pp. 171-174 ◽  
Author(s):  
John A. Sirs
Keyword(s):  
Ionic Strength ◽  
Membrane Permeability ◽  
Molar Concentration ◽  
Volume Changes ◽  
Effect Of Ph ◽  
Gas Concentration ◽  
Optimum Rate ◽  
Cyclic Variations ◽  
Predominant Factor ◽  
Ph Variations

Spectrophotometric measurements have been made of the effect of variation of the ionic strength, and equivalent molar concentration of sucrose, on the rate of uptake of CO and O2 by reduced erythrocytes. Cyclic variations of the rate of uptake by as much as 30% have been observed as the ionic strength is altered. The rate of uptake under these conditions is not proportional to the gas concentration. An analysis of these effects suggests the predominant factor is shape-volume changes which alter the membrane permeability. Similar observations have been made on the effect of pH variations. An optimum rate of uptake occurs at pH 7.4. Submitted on September 21, 1961

The ionic strength dependence of chromatin folding

1978 ◽  
Vol 36 (2) ◽  
pp. 220-221
Author(s):  
F. Thoma ◽  
TH. Koller
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Ionic Strength ◽  
Specimen Preparation ◽  
Preparation Technique ◽  
Carbon Supports ◽  
Ionic Strength Dependence ◽  
Chromatin Folding ◽  
Strength Dependence ◽  
Preparation Techniques

Under a variety of electron microscope specimen preparation techniques different forms of chromatin appearance can be distinguished: beads-on-a-string, a 100 Å nucleofilament, a 250 Å fiber and a compact 300 to 500 Å fiber.Using a standardized specimen preparation technique we wanted to find out whether there is any relation between these different forms of chromatin or not. We show that with increasing ionic strength a chromatin fiber consisting of a row of nucleo- somes progressively folds up into a solenoid-like structure with a diameter of about 300 Å.For the preparation of chromatin for electron microscopy the avoidance of stretching artifacts during adsorption to the carbon supports is of utmost importance. The samples are fixed with 0.1% glutaraldehyde at 4°C for at least 12 hrs. The material was usually examined between 24 and 48 hrs after the onset of fixation.

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