Comments on: Effect of turgor pressure on water permeability ofAllium cepa epidermis cell membranes

1978 ◽  
Vol 41 (1) ◽  
pp. 87-91 ◽  
Author(s):  
Ernst Steudle ◽  
Ulrich Zimmermann ◽  
J. P. Palta ◽  
E. J. Stadelmann
Keyword(s):  
Water Permeability ◽  
Cell Membranes ◽  
Turgor Pressure ◽  
Ofallium Cepa ◽  
Epidermis Cell

Water permeability of apical and basolateral cell membranes of rat inner medullary collecting duct

1990 ◽  
Vol 259 (6) ◽  
pp. F986-F999 ◽  
Author(s):  
B. Flamion ◽  
K. R. Spring
Keyword(s):  
Water Flow ◽  
Water Permeability ◽  
Cell Membranes ◽  
Apical Membrane ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Volume Regulatory Decrease ◽  
Water Permeation ◽  
Inner Medullary Collecting Duct ◽  
Medullary Collecting Duct

To quantify the pathways for water permeation through the kidney medulla, knowledge of the water permeability (Posmol) of individual cell membranes in inner medullary collecting duct (IMCD) is required. Therefore IMCD segments from the inner two thirds of inner medulla of Sprague-Dawley rats were perfused in vitro using a setup devised for rapid bath and luminal fluid exchanges (half time, t1/2, of 55 and 41 ms). Differential interference contrast microscopy, coupled to video recording, was used to measure volume and approximate surface areas of single cells. Volume and volume-to-surface area ratio of IMCD cells were strongly correlated with their position along the inner medullary axis. Transmembrane water flow (Jv) was measured in response to a variety of osmotic gradients (delta II) presented on either basolateral or luminal side of the cells. The linear relation between Jv and delta II yielded the cell membrane Posmol, which was then corrected for membrane infoldings. Basolateral membrane Posmol was 126 +/- 3 microns/s. Apical membrane Posmol rose from a basal value of 26 +/- 3 microns/s to 99 +/- 5 microns/s in presence of antidiuretic hormone (ADH). Because of amplification of basolateral membrane, the ADH-stimulated apical membrane remained rate-limiting for transcellular osmotic water flow, and the IMCD cell did not swell significantly. Calculated transcellular Posmol, expressed in terms of smooth luminal surface, was 64 microns/s without ADH and 207 microns/s with ADH. IMCD cells in anisosmotic media displayed almost complete volume regulatory decrease but only partial volume regulatory increase.

scholarly journals Water Permeability of Chlorella Cell Membranes by Nuclear Magnetic Resonance

1978 ◽  
Vol 62 (1) ◽  
pp. 146-151 ◽  
Author(s):  
Darryl G. Stout ◽  
Peter L. Steponkus ◽  
Larry D. Bustard ◽  
Robert M. Cotts
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Water Permeability ◽  
Cell Membranes ◽  
Chlorella Cell ◽  
Nuclear Magnetic

Osmotic water permeability of cell membranes from Mesembryanthemum crystallinum leaves: effects of age and salinity

2003 ◽  
Vol 118 (2) ◽  
pp. 232-239 ◽  
Author(s):  
Marina S. Trofimova ◽  
Inna M. Zhestkova ◽  
Valentina P. Kholodova ◽  
Igor M. Andreev ◽  
Evgeny M. Sorokin ◽  
...  
Keyword(s):  
Water Permeability ◽  
Cell Membranes ◽  
Mesembryanthemum Crystallinum ◽  
Osmotic Water Permeability ◽  
Osmotic Water

scholarly journals Turgor Pressure Sensing in Plant Cell Membranes

1976 ◽  
Vol 58 (5) ◽  
pp. 636-643 ◽  
Author(s):  
Hans G. L. Coster ◽  
Ernst Steudle ◽  
Ulrich Zimmermann
Keyword(s):  
Plant Cell ◽  
Cell Membranes ◽  
Turgor Pressure ◽  
Pressure Sensing ◽  
Plant Cell Membranes

scholarly journals Tetrameric assembly of CHIP28 water channels in liposomes and cell membranes: a freeze-fracture study.

1993 ◽  
Vol 123 (3) ◽  
pp. 605-618 ◽  
Author(s):  
J M Verbavatz ◽  
D Brown ◽  
I Sabolić ◽  
G Valenti ◽  
D A Ausiello ◽  
...  
Keyword(s):  
Water Permeability ◽  
Cho Cells ◽  
Cell Membranes ◽  
Plasma Membranes ◽  
Single Channel ◽  
Water Channel ◽  
Freeze Fracture ◽  
Water Channels ◽  
Straight Tubules ◽  
Tetrameric Assembly

Channel forming integral protein of 28 kD (CHIP28) functions as a water channel in erythrocytes, kidney proximal tubule and thin descending limb of Henle. CHIP28 morphology was examined by freeze-fracture EM in proteoliposomes reconstituted with purified CHIP28, CHO cells stably transfected with CHIP28k cDNA, and rat kidney tubules. Liposomes reconstituted with HPLC-purified CHIP28 from human erythrocytes had a high osmotic water permeability (Pf0.04 cm/s) that was inhibited by HgCl2. Freeze-fracture replicas showed a fairly uniform set of intramembrane particles (IMPs); no IMPs were observed in liposomes without incorporated protein. By rotary shadowing, the IMPs had a diameter of 8.5 +/- 1.3 nm (mean +/- SD); many IMPs consisted of a distinct arrangement of four smaller subunits surrounding a central depression. IMPs of similar size and appearance were seen on the P-face of plasma membranes from CHIP28k-transfected (but not mock-transfected) CHO cells, rat thin descending limb (TDL) of Henle, and S3 segment of proximal straight tubules. A distinctive network of complementary IMP imprints was observed on the E-face of CHIP28-containing plasma membranes. The densities of IMPs in the size range of CHIP28 IMPs, determined by non-linear regression, were (in IMPs/microns 2): 2,494 in CHO cells, 5,785 in TDL, and 1,928 in proximal straight tubules; predicted Pf, based on the CHIP28 single channel water permeability of 3.6 x 10(-14) cm3/S (10 degrees C), was in good agreement with measured Pf of 0.027 cm/S, 0.075 cm/S, and 0.031 cm/S, respectively, in these cell types. Assuming that each CHIP28 monomer is a right cylindrical pore of length 5 nm and density 1.3 g/cm3, the monomer diameter would be 3.2 nm; a symmetrical arrangement of four cylinders would have a greatest diameter of 7.2 nm, which after correction for the thickness of platinum deposit, is similar to the measured IMP diameter of approximately 8.5 nm. These results provide a morphological signature for CHIP28 water channels and evidence for a tetrameric assembly of CHIP28 monomers in reconstituted proteoliposomes and cell membranes.

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