The membrane permeability of nonelectrolytes and carbohydrate metabolism of Amazon fish red cells

1978 ◽  
Vol 56 (4) ◽  
pp. 863-869 ◽  
Author(s):  
Hyun Dju Kim ◽  
R. E. Isaacks
Keyword(s):  
Membrane Permeability ◽  
Carbohydrate Metabolism ◽  
Diffusion Mechanism ◽  
Red Cells ◽  
Facilitated Diffusion ◽  
Metabolic Substrates ◽  
Urea Permeability ◽  
Arapaima Gigas ◽  
Electric Eel ◽  
Order Of Magnitude

The membrane permeability to nonelectrolytes and carbohydrate metabolism were examined in red cells obtained from the Amazon fishes including the electric eel (Electrophorus electrocus), the arawana (Osteoglossum bicirrhosum), the pirarucu (Arapaima gigas), the lungfish (Lepidosireti paradoxa), and the armored catfish (Pterygoplichthys). Glucose permeability was fastest in the electric eel, followed by the lungfish. The red cells of the arawana were only slightly permeable to glucose. Both the armored catfish and the pirarucu red cells were found to be totally impermeable to glucose. There was no evidence for the presence of the facilitated diffusion mechanism for glucose transport in any of these fish red cells. In sharp contrast with glucose, red cells of all five species were quite permeable to ribose and urea. Urea permeability of red cells decreased in order of magnitude with the lungfish > the electric eel > the arawana > the armored catfish [Formula: see text] the pirarucu. The urea permeability of the lungfish was inhibited in the presence of phloretin.Of the two metabolic substrates, glucose but not ribose was metabolized to lactate with a concomitant contribution to ATP maintenance by the lungfish red cells. Even though the glucose-impervious pirarucu cells could not utilize glucose, ribose was readily metabolized by the pirarucu cells.

The osmotic fragility and critical hemolytic volume of red blood cells of Amazon fishes

1978 ◽  
Vol 56 (4) ◽  
pp. 860-862 ◽  
Author(s):  
Hyun Dju Kim ◽  
R. E. Isaacks
Keyword(s):  
Red Blood Cells ◽  
Blood Cells ◽  
Osmotic Fragility ◽  
Human Cells ◽  
Red Cells ◽  
Distilled Water ◽  
Arapaima Gigas ◽  
Electric Eel ◽  
Amazon Fish ◽  
Human Red Cells

The osmotic fragility and critical hemolytic volume were determined in red cells obtained from common Amazon fishes including the arawana (Osteoglossum bicirrhosum), the armored catfish (Pterygoplichthys), the electric eel (Electrophorus electrocus), the pirarucu (Arapaima gigas), and the lungfish (Lepidosiren paradoxa). The red cells of the pirarucu and the electric eel displayed the osmotic fragility profile remarkedly akin to human red cells, whereas the red cells of the armored catfish were considerably more resistant to hemolysis than human cells. The arawana cells exhibited a broad shoulder in the region of 120 mM to 70 mM followed by a complete hemolysis near 40 mM NaCl as in other fishes. Unexpectedly, the lungfish red cells were found to be extraordinarily resistant to hemolysis. A 15-min and a 1-h exposure of the lungfish cells to distilled water resulted in hemolysis of 55 and 80%, respectively. The critical hemolytic volume of Amazon fish red cells thus far examined was of the order of 1.83–2.03, except the pirarucu red cells which had a low value of 1.25.

scholarly journals Red Cell Membrane Permeability Deduced from Bulk Diffusion Coefficients

1974 ◽  
Vol 64 (6) ◽  
pp. 706-729 ◽  
Author(s):  
W. R. Redwood ◽  
E. Rall ◽  
W. Perl
Keyword(s):  
Cell Membrane ◽  
Membrane Permeability ◽  
Diffusion Coefficients ◽  
Bulk Diffusion ◽  
Red Cells ◽  
Cell Membrane Permeability ◽  
Red Cell ◽  
Cell Column ◽  
Red Cell Membrane ◽  
One Dimensional

The permeability coefficients of dog red cell membrane to tritiated water and to a series of[14C]amides have been deduced from bulk diffusion measurements through a "tissue" composed of packed red cells. Red cells were packed by centrifugation inside polyethylene tubing. The red cell column was pulsed at one end with radiolabeled solute and diffusion was allowed to proceed for several hours. The distribution of radioactivity along the red cell column was measured by sequential slicing and counting, and the diffusion coefficient was determined by a simple plotting technique, assuming a one-dimensional diffusional model. In order to derive the red cell membrane permeability coefficient from the bulk diffusion coefficient, the red cells were assumed to be packed in a regular manner approximating closely spaced parallelopipeds. The local steady-state diffusional flux was idealized as a one-dimensional intracellular pathway in parallel with a one-dimensional extracellular pathway with solute exchange occurring within the series pathway and between the pathways. The diffusion coefficients in the intracellular and extracellular pathways were estimated from bulk diffusion measurements through concentrated hemoglobin solutions and plasma, respectively; while the volume of the extracellular pathway was determined using radiolabeled sucrose. The membrane permeability coefficients were in satisfactory agreement with the data of Sha'afi, R. I., C. M. Gary-Bobo, and A. K. Solomon (1971. J. Gen. Physiol. 58:238) obtained by a rapid-reaction technique. The method is simple and particularly well suited for rapidly permeating solutes.

Osmotic stability of red cells in renal circulation requires rapid urea transport

1988 ◽  
Vol 254 (5) ◽  
pp. C669-C674 ◽  
Author(s):  
R. I. Macey ◽  
L. W. Yousef
Keyword(s):  
Lipid Bilayers ◽  
Physiological Role ◽  
Renal Medulla ◽  
Red Cells ◽  
Facilitated Diffusion ◽  
Urea Transport ◽  
Permeability Characteristics ◽  
Cortex Cell ◽  
Cell Stability ◽  
Michaelis Constants

Urea transport by the human erythrocyte occurs via an asymmetric-facilitated diffusion system with high Michaelis constants and high maximal velocities; the equivalent permeability in the limit of zero urea concentration is approximately 10(-3) cm/s (J. Gen. Physiol. 81: 221-237, 239-253, 1983). A physiological role for this system is revealed by numerical integration of the appropriate equations that show that rapid urea transport is essential for red cell stability in passing through the renal medulla. The calculation compares two cells. Cell A transports urea with permeability characteristics of normal red cells; cell B has urea permeability similar to lipid bilayers. On entering the hypertonic medulla, both cells shrink, but only B swells on leaving the medulla. The osmotic stress for cell B is greater than for A. Cell B is close to hypertonic hemolysis in the medulla and to hypotonic hemolysis in the cortex. Cell B remains swollen for some time after its exit; the resulting decreased deformability presents a hazard if B reenters the microcirculation. Furthermore, cell B removes a significant fraction of the filtered load of urea and compromises the osmotic gradients in the medulla.

scholarly journals PnuT uses a facilitated diffusion mechanism for thiamine uptake

2017 ◽  
Vol 150 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Michael Jaehme ◽  
Rajkumar Singh ◽  
Alisa A. Garaeva ◽  
Ria H. Duurkens ◽  
Dirk-Jan Slotboom
Keyword(s):  
Substrate Binding ◽  
Diffusion Mechanism ◽  
Vitamin B1 ◽  
Pyridine Nucleotide ◽  
Thiamine Pyrophosphate ◽  
Facilitated Diffusion ◽  
Nicotinamide Riboside ◽  
Thiamine Transport ◽  
Shewanella Woodyi ◽  
Thiamine Analogues

Membrane transporters of the bacterial pyridine nucleotide uptake (Pnu) family mediate the uptake of various B-type vitamins. For example, the PnuT transporters have specificity for vitamin B1 (thiamine). It has been hypothesized that Pnu transporters are facilitators that allow passive transport of the vitamin substrate across the membrane. Metabolic trapping by phosphorylation would then lead to accumulation of the transported substrates in the cytoplasm. However, experimental evidence for such a transport mechanism is lacking. Here, to determine the mechanism of thiamine transport, we purify PnuTSw from Shewanella woodyi and reconstitute it in liposomes to determine substrate binding and transport properties. We show that the electrochemical gradient of thiamine solely determines the direction of transport, consistent with a facilitated diffusion mechanism. Further, PnuTSw can bind and transport thiamine as well as the thiamine analogues pyrithiamine and oxythiamine, but does not recognize the phosphorylated derivatives thiamine monophosphate and thiamine pyrophosphate as substrates, consistent with a metabolic trapping mechanism. Guided by the crystal structure of the homologous nicotinamide riboside transporter PnuC, we perform mutagenesis experiments, which reveal residues involved in substrate binding and gating. The facilitated diffusion mechanism of transport used by PnuTSw contrasts sharply with the active transport mechanisms used by other bacterial thiamine transporters.

scholarly journals Real sequence effects on the search dynamics of transcription factors on DNA

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Maximilian Bauer ◽  
Emil S. Rasmussen ◽  
Michael A. Lomholt ◽  
Ralf Metzler
Keyword(s):  
Transcription Factors ◽  
Target Detection ◽  
Diffusion Mechanism ◽  
Coli Strain ◽  
Dna Looping ◽  
Real Sequence ◽  
Facilitated Diffusion ◽  
E Coli ◽  
Sliding Motion ◽  
Sequence Effects

Abstract Recent experiments show that transcription factors (TFs) indeed use the facilitated diffusion mechanism to locate their target sequences on DNA in living bacteria cells: TFs alternate between sliding motion along DNA and relocation events through the cytoplasm. From simulations and theoretical analysis we study the TF-sliding motion for a large section of the DNA-sequence of a common E. coli strain, based on the two-state TF-model with a fast-sliding search state and a recognition state enabling target detection. For the probability to detect the target before dissociating from DNA the TF-search times self-consistently depend heavily on whether or not an auxiliary operator (an accessible sequence similar to the main operator) is present in the genome section. Importantly, within our model the extent to which the interconversion rates between search and recognition states depend on the underlying nucleotide sequence is varied. A moderate dependence maximises the capability to distinguish between the main operator and similar sequences. Moreover, these auxiliary operators serve as starting points for DNA looping with the main operator, yielding a spectrum of target detection times spanning several orders of magnitude. Auxiliary operators are shown to act as funnels facilitating target detection by TFs.

scholarly journals THE MECHANISM OF THE INFLAMMATORY PROCESS

1928 ◽  
Vol 11 (6) ◽  
pp. 743-756 ◽  
Author(s):  
Harold A. Abramson
Keyword(s):  
Magnetic Force ◽  
Marked Change ◽  
Polymorphonuclear Leucocyte ◽  
Red Cells ◽  
Fibrin Gels ◽  
Gelatin Gels ◽  
Order Of Magnitude ◽  
And Migration ◽  
Soft Gels ◽  
Mechanical Nature

1. Quartz particles and certain other particles move cataphoretically in certain soft gelatin gels, with the same velocity as in the sol. The speed is a function of the true viscosity of the sol or gel, and it is See PDF for Structure apparently not altered in these soft gels by the presence of gel structure. It is proportional to the applied difference of potential. 2. This finding is compatible with the fact that certain sols undergo gelation with no increase of the true viscosity although a marked change in the apparent viscosity takes place. 3. Red cells in soft gelatin-serum gels show a distinct difference in behavior. They migrate through the sol or gel with a speed that is about twice as great as the leucocytes and quartz particles, which latter particles migrate with the same velocity. This ratio has been found to hold for serum and plasma. The absolute velocities are comparatively slightly decreased by the presence of the gel. 4. In more concentrated or stiffer gels, leucocytes, red cells and quartz particles all move at first with the same velocity. By producing mechanical softening of these gels (shearing from cataphoretic movement of the micells within the cell) the red cells presently resume their previous property of independent migration through the gel. 5. The movements of particles in gelatin gels produced by a magnetic force or the force of gravity are of a different nature than those movements produced by cataphoresis. 6. The mechanical nature of obstruction to the cataphoretic migration of leucocytes and red cells in fibrin gels is briefly described. 7. The correlation of cataphoresis of microscopic particles in gels with the order of magnitude and nature of the potential differences in the capillary wall, lends additional evidence to the theory that polymorphonuclear leucocyte emigration and migration are dependent upon these potential differences.

scholarly journals Analytical Review: Leaky Red Cells

Blood ◽  
1965 ◽  
Vol 26 (3) ◽  
pp. 367-382 ◽  
Author(s):  
JAMES H. JANDL
Keyword(s):  
Membrane Permeability ◽  
Active Transport ◽  
Hereditary Spherocytosis ◽  
Metabolic Stress ◽  
Glucose Deprivation ◽  
Red Cells ◽  
Osmotic Swelling ◽  
Permeability Changes ◽  
Metabolic Conditions ◽  
Analytical Review

Abstract The normal survival of red cells requires maintained regulation of cell size and shape. This regulation is to a large extent dependent upon membrane permeability and the active transport of cations. Agents such as C' that affect permeability markedly by creating large holes in the membrane lead to rapid cell death. Most hemolytic disorders thus far studied involve lesser increases in membrane permeability and hemolysis occurs more gradually by the sequence of colloid osmotic swelling, loss of cell surface, and spherocytosis. With very mild permeability changes, as in hereditary spherocytosis, the cell may compensate for an increased leak-rate for cations by increased active transport. This compensation requires increased glycolysis and optimal metabolic conditions, however, and the cell rapidly decompensates during glucose deprivation or metabolic stress. The interaction between reticuloendothelial tissues and red cells provides such a stress for leaky cells and hastens their destruction.

scholarly journals The Uptake of Divalent Manganese Ion by Mature Normal Human Red Blood Cells

1960 ◽  
Vol 44 (2) ◽  
pp. 301-314 ◽  
Author(s):  
Robert I. Weed ◽  
Aser Rothstein
Keyword(s):  
Red Cells ◽  
Metabolic Inhibitors ◽  
Entry And Exit ◽  
Permeability Constant ◽  
Manganese Ion ◽  
Human Red Blood Cells ◽  
Metabolic Substrates ◽  
Normal Human ◽  
High Concentrations ◽  
Mn Concentration

At physiological pH and concentrations of Mn++ in excess of 5 x 10-4 M, study of the Mn++ ion movement into human red cells is complicated by physicochemical alterations of the ion itself. At concentrations below 5 x 10x4 M, the rate of uptake bears a linear relationship to the Mn++ concentration. The permeability constant for inward movement of Mn++ is 2.87 ± 0.13 (S.E.) x 10-9 cm./sec. The rate is not influenced by the addition of metabolic substrates such as glucose or adenosine or the metabolic inhibitors iodoacetate or fluoride. Co++, Ca++, and Mg++ do not appear to compete with Mn++ for entry, but at high concentrations relative to Mn++, they reduce the rate of entry. Ca++ is far more effective than Co++ or Mg++ in this regard. The permeability constant for outward Mn++ movement is 1.38 ± 0.21 (S.E.) x 10-9 cm./sec., about half of that for entry. This slower rate of outward movement is consistent with the finding that 40 to 60 per cent of the Mn++ taken up by the red cells is non-ultrafilterable. Less than 5 to 10 per cent of the Mn++ appears to be bound to the stroma. It is concluded that entry and exit of Mn++ is a process of passive diffusion involving no carriers, transport, or metabolic linkage.

The Effect of Plasma from Schizophrenic Patients on the Chicken Erythrocyte System

1963 ◽  
Vol 109 (459) ◽  
pp. 231-234 ◽  
Author(s):  
A. Mangoni ◽  
R. Balazs ◽  
A. J. Coppen
Keyword(s):  
Carbohydrate Metabolism ◽  
Normal Subjects ◽  
Aerobic Metabolism ◽  
Red Cells ◽  
Chicken Erythrocyte ◽  
Schizophrenic Patients ◽  
Lactate And Pyruvate ◽  
Pyruvate Ratio

Frohman et al. (1960a, 1960b, 1961, 1962) have investigated the effect of plasma of schizophrenic patients on carbohydrate metabolism. They measured the production of lactate and pyruvate by the nucleated red cells of the chicken after incubation with patients' plasma. After incubation with plasma from schizophrenic patients, the lactate/pyruvate ratio was raised significantly above the ratio found after incubation with plasma from normal subjects. This observation was interpreted as evidence of an inhibition of aerobic metabolism induced by the plasma of schizophrenic patients. We report here an attempt to confirm these findings.

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