scholarly journals The Effect of Amphotericin B on the Water and Nonelectrolyte Permeability of Thin Lipid Membranes

1969 ◽  
Vol 53 (2) ◽  
pp. 133-156 ◽  
Author(s):  
Thomas E. Andreoli ◽  
Vincent W. Dennis ◽  
Ann M. Weigl
Keyword(s):  
Amphotericin B ◽  
Lipid Membranes ◽  
Permeability Coefficient ◽  
Circular Cylinders ◽  
Osmotic Water Permeability ◽  
Polyene Antibiotic ◽  
Water Permeability Coefficient ◽  
Osmotic Water ◽  
Membrane Bound ◽  
Nonelectrolyte Permeability

This paper reports the effects of amphotericin B, a polyene antibiotic, on the water and nonelectrolyte permeability of optically black, thin lipid membranes formed from sheep red blood cell lipids dissolved in decane. The permeability coefficients for the diffusion of water and nonelectrolytes (PDDi) were estimated from unidirectional tracer fluxes when net water flow (Jw) was zero. Alternatively, an osmotic water permeability coefficient (Pf) was computed from Jw when the two aqueous phases contained unequal solute concentrations. In the absence of amphotericin B, when the membrane solutions contained equimolar amounts of cholesterol and phospholipid, Pf was 22.9 ± 4.6 µsec-1 and PDDHDH2O was 10.8 ± 2.4 µsec-1. Furthermore, PDDi was < 0.05 µsec-1 for urea, glycerol, ribose, arabinose, glucose, and sucrose, and σi, the reflection coefficient of each of these solutes was one. When amphotericin B (10-6 M) was present in the aqueous phases and the membrane solutions contained equimolar amounts of cholesterol and phospholipid, PDDHDH2O was 18.1 ± 2.4 µsec-1; Pf was 549 ± 143 µsec-1 when glucose, sucrose, and raffinose were the aqueous solutes. Concomitantly, PDDi varied inversely, and σi directly, with the effective hydrodynamic radii of the solutes tested. These polyene-dependent phenomena required the presence of cholesterol in the membrane solutions. These data were analyzed in terms of restricted diffusion and filtration through uniform right circular cylinders, and were compatible with the hypothesis that the interactions of amphotericin B with membrane-bound cholesterol result in the formation of pores whose equivalent radii are in the range 7 to 10.5 A.

scholarly journals The Water and Nonelectrolyte Permeability Induced in Thin Lipid Membranes by the Polyene Antibiotics Nystatin and Amphotericin B

1970 ◽  
Vol 56 (1) ◽  
pp. 125-145 ◽  
Author(s):  
Ronald Holz ◽  
Alan Finkelstein
Keyword(s):  
Amphotericin B ◽  
Lipid Membranes ◽  
Permeability Coefficient ◽  
Membrane Conductance ◽  
Red Cell Membrane ◽  
Water Permeability Coefficient ◽  
Permeability Increase ◽  
Hydrophilic Solutes ◽  
Human Red Cell Membrane ◽  
Nonelectrolyte Permeability

Nystatin and amphotericin B increase the permeability of thin (<100 A) lipid membranes to ions, water, and nonelectrolytes. Water and nonelectrolyte permeability increase linearly with membrane conductance (i.e., ion permeability). In the unmodified membrane, the osmotic permeability coefficient, Pf, is equal to the tagged water permeability coefficient, (Pd)w; in the nystatin- or amphotericin B-treated membrane, Pf/(Pd)w ≈ 3. The unmodified membrane is virtually impermeable to small hydrophilic solutes, such as urea, ethylene glycol, and glycerol; the nystatin- or amphotericin B-treated membrane displays a graded permeability to these solutes on the basis of size. This graded permeability is manifest both in the tracer permeabilities, Pd, and in the reflection coefficients, σ (Table I). The "cutoff" in permeability occurs with molecules about the size of glucose (Stokes-Einstein radius ≊ 4 A). We conclude that nystatin and amphotericin B create aqueous pores in thin lipid membranes; the effective radius of these pores is approximately 4 A. There is a marked similarity between the permeability of a nystatin- or amphotericin B-treated membrane to water and small hydrophilic solutes and the permeability of the human red cell membrane to these same molecules.

Cell osmotic water permeability of isolated rabbit proximal straight tubules

1982 ◽  
Vol 242 (4) ◽  
pp. F321-F330 ◽  
Author(s):  
E. Gonzalez ◽  
P. Carpi-Medina ◽  
G. Whittembury
Keyword(s):  
Surface Area ◽  
Water Flow ◽  
Water Permeability ◽  
Permeability Coefficient ◽  
Osmotic Water Permeability ◽  
Water Permeability Coefficient ◽  
Osmotic Water ◽  
Straight Tubules ◽  
Tubular Surface ◽  
Set Up

Proximal straight tubules were dissected and mounted in a chamber with their lumina occluded. The well-stirred bath could be 95% changed within 84 ms to set up osmotic gradients (delta Coi) across the peritubular cell aspect. Volume changes (less than or equal to 10 pl/mm) were estimated from continuous records of diameter changes (error less than 0.1 micrometers). delta Coi greater than or equal to 2-3 mosM could be discerned. delta Coi values from 10 to 44 mosM were used to evaluate Posc, the cell osmotic water permeability coefficient, and extrapolated to delta Coi = 0. Posc = 25.1 (+/- 2.3) X 10(-4) cm3.s-1.osM-1.cm2 tubular surface area-1. These values are lower than those reported for Pose, the transepithelial osmotic water permeability coefficient, and become lower if corrected for the real (infolded) peritubular cell surface area. Thus, for a given osmotic difference, transcellular water flow finds a higher resistance than paracellular water flow. Experiments were also performed with delta Coi greater than 100 mosM, but interpretation of these data is difficult because of the presence of volume regulatory phenomena and other undesirable effects.

scholarly journals Osmosis in Cortical Collecting Tubules

1974 ◽  
Vol 64 (2) ◽  
pp. 201-228 ◽  
Author(s):  
James A. Schafer ◽  
Clifford S. Patlak ◽  
Thomas E. Andreoli
Keyword(s):  
Steady State ◽  
Water Permeability ◽  
Permeability Coefficient ◽  
Osmotic Water Permeability ◽  
Osmotic Flow ◽  
Unstirred Layers ◽  
Water Permeability Coefficient ◽  
Osmotic Water ◽  
In Series ◽  
Collecting Tubules

This paper reports a theoretical analysis of osmotic transients and an experimental evaluation both of rapid time resolution of lumen to bath osmosis and of bidirectional steady-state osmosis in isolated rabbit cortical collecting tubules exposed to antidiuretic hormone (ADH). For the case of a membrane in series with unstirred layers, there may be considerable differences between initial and steady-state osmotic flows (i.e., the osmotic transient phenomenon), because the solute concentrations at the interfaces between membrane and unstirred layers may vary with time. A numerical solution of the equation of continuity provided a means for computing these time-dependent values, and, accordingly, the variation of osmotic flow with time for a given set of parameters including: Pf (cm s–1), the osmotic water permeability coefficient, the bulk phase solute concentrations, the unstirred layer thickness on either side of the membrane, and the fractional areas available for volume flow in the unstirred layers. The analyses provide a quantitative frame of reference for evaluating osmotic transients observed in epithelia in series with asymmetrical unstirred layers and indicate that, for such epithelia, Pf determinations from steady-state osmotic flows may result in gross underestimates of osmotic water permeability. In earlier studies, we suggested that the discrepancy between the ADH-dependent values of Pf and PDDw (cm s–1, diffusional water permeability coefficient) was the consequence of cellular constraints to diffusion. In the present experiments, no transients were detectable 20–30 s after initiating ADH-dependent lumen to bath osmosis; and steady-state ADH-dependent osmotic flows from bath to lumen and lumen to bath were linear and symmetrical. An evaluation of these data in terms of the analytical model indicates: First, cellular constraints to diffusion in cortical collecting tubules could be rationalized in terms of a 25-fold reduction in the area of the cell layer available for water transport, possibly due in part to transcellular shunting of osmotic flow; and second, such cellular constraints resulted in relatively small, approximately 15%, underestimates of Pf.

scholarly journals Effect of Osmolality on the Hydraulic Permeability Coefficient of Red Cells

1968 ◽  
Vol 52 (6) ◽  
pp. 941-954 ◽  
Author(s):  
G. T. Rich ◽  
R. I. Sha'afi ◽  
A. Romualdez ◽  
A. K. Solomon
Keyword(s):  
Permeability Coefficient ◽  
Water Movement ◽  
Red Cells ◽  
Hydraulic Permeability ◽  
Outer Face ◽  
Bathing Medium ◽  
Water Permeability Coefficient ◽  
Osmotic Water ◽  
Similar Decrease ◽  
Human Red Cells

The osmotic water permeability coefficient, Lp, for human and dog red cells has been measured as a function of medium osmolality, and found to depend on the osmolality of the bathing medium. In the case of human red cells Lp falls from 1.87 x 10-11 cm3/dyne sec at 199 mOSM to 0.76 x 10-11 cm3/dyne sec at 516 mOSM. A similar decrease was observed for dog red cells. Moreover, Lp was independent of the direction of water movement and the nature of the solute used to provide the osmotic pressure gradient; it depended only on the final osmolality of the medium. Furthermore, Lp was not affected by pH in the range of 6 to 8 nor by the presence of drugs such as valinomycin (1 x 10-6 M) and tetrodotoxin (3.2 x 10-6 M). The instantaneous nature of the response to changes in external osmolality suggests that the hydraulic conductivity of the membrane is controlled by a thin layer at the outer face of the membrane.

Membrane organization and function of M1 and M23 isoforms of aquaporin-4 in epithelial cells

2004 ◽  
Vol 287 (3) ◽  
pp. F501-F511 ◽  
Author(s):  
Claudia Silberstein ◽  
Richard Bouley ◽  
Yan Huang ◽  
Pingke Fang ◽  
Nuria Pastor-Soler ◽  
...  
Keyword(s):  
Water Permeability ◽  
Single Channel ◽  
Phosphorylation Site ◽  
Freeze Fracture ◽  
Parietal Cells ◽  
Aquaporin 4 ◽  
Osmotic Water Permeability ◽  
Cellular Expression ◽  
Water Permeability Coefficient ◽  
Osmotic Water

Aquaporin-4 (AQP4) water channels exist as heterotetramers of M1 and M23 splice variants and appear to be present in orthogonal arrays of intramembraneous particles (OAPs) visualized by freeze-fracture microscopy. We report that AQP4 forms OAPs in rat gastric parietal cells but not in parietal cells from the mouse or kangaroo rat. Furthermore, the organization of principal cell OAPs in Brattleboro rat kidney is perturbed by vasopressin (arginine vasopressin). Membranes of LLC-PK1 cells expressing M23-AQP4 showed large, abundant OAPs, but none were detectable in cells expressing M1-AQP4. Measurements of osmotic swelling of transfected LLC-PK1 cells using videomicroscopy, gave osmotic water permeability coefficient ( Pf) values (in cm/s) of 0.018 (M1-AQP4), 0.019 (M23-AQP4), and 0.003 (control). Quantitative immunoblot and immunofluorescence showed an eightfold greater expression of M1- over M23-AQP4 in the cell lines, suggesting that single-channel pf (cm3/s) is much greater for the M23 variant. Somatic fusion of M1- and M23-AQP4 cells ( Pf = 0.028 cm/s) yielded OAPs that were fewer and smaller than in M23 cells alone, and M1-to-M23 expression ratios (∼1:4) normalized to AQP4 in M1 or M23 cells indicated a reduced single-channel pf for the M23 variant. Expression of an M23-AQP4-Ser111E mutant produced ∼1.5-fold greater single-channel pf and OAPs that were up to 2.5-fold larger than wild-type M23-AQP4 OAPs, suggesting that a putative PKA phosphorylation site Ser111 is involved in OAP formation. We conclude that the higher-order organization of AQP4 in OAPs increases single-channel osmotic water permeability by one order of magnitude and that differential cellular expression levels of the two isoforms could regulate this organization.

scholarly journals The Interaction of Polyene Antibiotics with Thin Lipid Membranes

1968 ◽  
Vol 52 (2) ◽  
pp. 300-325 ◽  
Author(s):  
Thomas E. Andreoli ◽  
Marcia Monahan
Keyword(s):  
Amphotericin B ◽  
Lipid Membranes ◽  
Sheep Erythrocyte ◽  
Cholesterol Content ◽  
Transference Numbers ◽  
Ionic Selectivity ◽  
Antibiotic Concentration ◽  
Polyene Antibiotics ◽  
Cyclic Polyene ◽  
Membrane Bound

Optically black, thin lipid membranes prepared from sheep erythrocyte lipids have a high dc resistance (Rm ≅ 108 ohm-cm2) when the bathing solutions contain NaCl or KCl. The ionic transference numbers (Ti) indicate that these membranes are cation-selective (TNa ≅ 0.85; TCl ≅ 0.15). These electrical properties are independent of the cholesterol content of the lipid solutions from which the membranes are formed. Nystatin, and probably amphotericin B, are cyclic polyene antibiotics containing ≈36 ring atoms and a free amino and carboxyl group. When the lipid solutions used to form membranes contained equimolar amounts of cholesterol and phospholipid, these antibiotics reduced Rm to ≈102 ohm-cm2; concomitantly, TCl became ≅0.92. The slope of the line relating log Rm and log antibiotic concentration was ≅4.5. Neither nystatin (2 x 10-5 M) nor amphotericin B (2 x 10-7 M) had any effect on membrane stability. The antibiotics had no effect on Rm or membrane permselectivity when the lipids used to form membranes were cholesterol-depleted. Filipin (10-5 M), an uncharged polyene with 28 ring atoms, produced striking membrane instability, but did not affect Rm or membrane ionic selectivity. These data suggest that amphotericin B or nystatin may interact with membrane-bound sterols to produce multimolecular complexes which greatly enhance the permeability of such membranes for anions (Cl-, acetate), and, to a lesser degree, cations (Na+, K+, Li+).

Water and nonelectrolyte permeability in brain synaptosomes isolated from normal and uremic rats

1986 ◽  
Vol 250 (2) ◽  
pp. R306-R312 ◽  
Author(s):  
A. S. Verkman ◽  
C. L. Fraser
Keyword(s):  
Light Scattering ◽  
Permeability Coefficient ◽  
Time Course ◽  
Scattered Light ◽  
Volume Ratio ◽  
High Energy ◽  
Urea Transport ◽  
Water Permeability Coefficient ◽  
Osmotic Water ◽  
Water Efflux

Water and nonelectrolyte permeabilities of synaptosomes isolated from the brain of normal and uremic rats were measured by stopped-flow light scattering. Intensity of scattered light (550 nm) increased linearly with decreasing synaptosome size in the range of normal size to 30% of normal size. In response to a 250-mM inwardly directed gradient of an impermeant solute (mannitol or sucrose), there was a 100- to 500-ms time course of increased light scattering resulting from osmotic water efflux. In response to an inwardly directed urea gradient, light scattering first increased (water efflux) and then decreased (urea influx) over a 2- to 10-s time course. Based on an average synaptosome surface-to-volume ratio of 86,000 cm-1, determined by electron microscopy, the permeability coefficient for osmotic water transport (Pf) is 4.5 X 10(-3) cm/s and for urea transport (Purea) is 1.5 X 10(-6) cm/s (23 degrees C); temperature-dependent studies gave an activation energy for Pf of 18 (greater than 16 degrees C) and 3 kcal/mol (less than 16 degrees C) and for Purea of 9.8 kcal/mol (10-55 degrees C). Osmotic water and urea transport were not inhibited by 2 mM p-chloromercuribenzene sulfonate, 120 microM phloretin, and 10 microM phenylurea or by exposure to high-energy radiation (0-10 Mrad). Diffusional water permeability coefficient is approximately 4 X 10(-4) cm/s based on the time course of light scattering after mixture of synaptosomes in D2O buffer with isosmotic H2O buffer. Water and urea transport properties of synaptosomes isolated from uremic rats were not significantly different from those of normal rats.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Molecular Aspects of Polyene- and Sterol-Dependent Pore Formation in Thin Lipid Membranes

1970 ◽  
Vol 55 (3) ◽  
pp. 375-400 ◽  
Author(s):  
Vincent W. Dennis ◽  
Nancy W. Stead ◽  
Thomas E. Andreoli
Keyword(s):  
Amphotericin B ◽  
Lipid Membranes ◽  
Free Sterol ◽  
Pore Formation ◽  
Membrane Resistance ◽  
Ionic Selectivity ◽  
Ring Compounds ◽  
Permeability Changes ◽  
Membrane Bound ◽  
Molecular Aspects

Amphotericin B modifies the permeability properties of thin lipid membranes formed from solutions containing sheep red cell phospholipids and cholesterol. At 10-6 M amphotericin B, the DC membrane resistance fell from ≈108 to ≈102 ohm-cm2, and the membranes became Cl--, rather than Na+-selective; the permeability coefficients for hydrophilic nonelectrolytes increased in inverse relationship to solute size, and the rate of water flow during osmosis increased 30-fold. These changes may be rationalized by assuming that the interaction of amphotericin B with membrane-bound sterol resulted in the formation of aqueous pores. N-acetylamphotericin B and the methyl ester of N-acetylamphotericin B, but not the smaller ring compounds, filipin, rimocidin, and PA-166, produced comparable permeability changes in identical membranes, and amphotericin B and its derivatives produced similar changes in the properties of membranes formed from phospholipid-free sterol solutions. However, amphotericin B did not affect ionic selectivity or water and nonelectrolyte permeability in membranes formed from solutions containing phospholipids and no added cholesterol, or when cholesterol was replaced by either cholesterol palmitate, dihydrotachysterol, epicholesterol, or Δ5-cholesten-3-one. Phospholipid-free sterol membranes exposed to amphotericin B or its derivatives were anion-selective, but the degree of Cl- selectivity varied among the compounds, and with the aqueous pH. The data are discussed with regard to, first, the nature of the polyene-sterol interactions which result in pore formation, and second, the functional groups on amphotericin B responsible for membrane anion selectivity.

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