scholarly journals Water Permeability of a Characean Internodal Cell with Special Reference to Its Polarity

1966 ◽  
Vol 19 (3) ◽  
pp. 399 ◽  
Author(s):  
M Tazawa ◽  
N Kamiya
Keyword(s):  
Hydraulic Conductivity ◽  
Special Reference ◽  
Cell Volume ◽  
Normal Level ◽  
Water Permeability ◽  
Forward Osmosis ◽  
External Concentration ◽  
Internodal Cell ◽  
Final Level ◽  
Transcellular Osmosis

Water permeability (hydraulic conductivity) of the Nitella internode was studied by means of transcellular osmosis with special reference to its polarity. It was shown that the change in turgor or in cell volume involved in transcellular osmosis is ahnost over within 5 sec after the onset of both forward and backward osmoses. What is different with respect to turgor between the two osmoses is its final level. In forward osmosis the turgor drops down to a definite level depending on the external concentration, while in backward osmosis the turgor invariably comes back to the normal level.

Enhancing Water Permeability with Super-hydrophilic Metal-Organic Frameworks and Hydrophobic Straight Pores

2021 ◽  
Author(s):  
Mehdi Habibollahzadeh ◽  
Juran Noh ◽  
Liang Feng ◽  
Hong-Cai Zhou ◽  
Ahmed Abdel-Wahab ◽  
...  
Keyword(s):  
Osmotic Pressure ◽  
Water Permeability ◽  
Metal Organic Frameworks ◽  
Water Flux ◽  
Forward Osmosis ◽  
High Water ◽  
Metal Organic

High water flux and salt selectivity have been the most demanding goals for osmosis-based membranes. Osmotic pressure differences across membranes are particularly important in emerging forward osmosis and pressure retarded...

CHROMOSOME DIFFERENTIATION IN POLYPLOID SPECIES OF ELYTRIGIA, WITH SPECIAL REFERENCE TO THE EVOLUTION OF DIPLOID-LIKE CHROMOSOME PAIRING IN POLYPLOID SPECIES

1981 ◽  
Vol 23 (2) ◽  
pp. 287-303 ◽  
Author(s):  
J. Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Special Reference ◽  
Normal Level ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Triticum Aestivum L ◽  
Polyploid Species ◽  
Chromosome Differentiation

Triticum aestivum L. em Thell ditelosomics 7AL and 7DS and T. aestivum-Elytrigia elongata (Host) Holub (2n = 2x = 14) ditelosomic additions were crossed with "E. elongata 4x" (2n = 4x = 28), E. caespitosa (C. Koch) Nevski (2n = 4x = 28), and E. intermedia (Host) Nevski (2n = 6x = 42). The effect of each Elytrigia genotype on homoeologous (heterogenetic) chromosome pairing was assessed by comparing the pairing frequencies of T. aestivum cv. Chinese Spring telosomes 7AL and 7DS in the hybrids with the pairing frequency of telosome 7AL in haploid Chinese Spring. The genotype of "E. elongata 4x" had no effect on heterogenetic pairing in the hybrids. Although some genotypes of E. caespitosa and E. intermedia promoted heterogenetic pairing in the hybrids, others had no effect. Telosome VS of E. elongata interacted in a complementary fashion with the genotype of "E. elongata 4x," but not with the genotypes of Chinese Spring and E. caespitosa, and it promoted heterogenetic pairing. In hybrids in which the wheat diploidizing genes were active at the normal level, the E. elongata telosomes paired with chromosomes of "E. elongata 4x" in 5.8% to 24.6% of the cells, with chromosomes of E. caespitosa in 0.0% to 1.0% of the cells, and with chromosomes of E. intermedia in 0.0% to 2.8% of the cells. A model of chromosome differentiation is discussed and special attention is devoted to the origin of diploid-like pairing in polyploid species.

scholarly journals Controlled aquaporin-2 expression in the hypertonic environment

2009 ◽  
Vol 296 (4) ◽  
pp. C641-C653 ◽  
Author(s):  
Udo Hasler
Keyword(s):  
Cell Volume ◽  
Water Permeability ◽  
Driving Force ◽  
Collecting Duct ◽  
Urine Concentration ◽  
Functional Change ◽  
Cell Phenotype ◽  
Renal Cells ◽  
Water Reabsorption ◽  
Principal Cells

The corticomedullary osmolality gradient is the driving force for water reabsorption occurring in the kidney. In the collecting duct, this gradient allows luminal water to move across aquaporin (AQP) water channels, thereby increasing urine concentration. However, this same gradient exposes renal cells to great osmotic challenges. These cells must constantly adapt to fluctuations of environmental osmolality that challenge cell volume and incite functional change. This implies profound alterations of cell phenotype regarding water permeability. AQP2 is an essential component of the urine concentration mechanism whose controlled expression dictates apical water permeability of collecting duct principal cells. This review focuses on changes of AQP2 abundance and trafficking in hypertonicity-challenged cells. Intracellular mechanisms governing these events are discussed and the biological relevance of altered AQP2 expression by hypertonicity is outlined.

scholarly journals Water Permeability in Resting and Stimulated Crayfish Nerve

1969 ◽  
Vol 54 (4) ◽  
pp. 462-478 ◽  
Author(s):  
B. Gunnar Wallin
Keyword(s):  
Hydrostatic Pressure ◽  
Hydraulic Conductivity ◽  
Water Permeability ◽  
Calcium Concentration ◽  
Procambarus Clarkii ◽  
Silicone Oil ◽  
Ionic Conductance ◽  
Volume Increase ◽  
External Calcium

The hydraulic conductivity, Lp, was determined in single axons of the crayfish, Procambarus clarkii, by injecting a hypertonic sample between two drops of silicone oil and photographing the volume increase of the sample. The method has the advantage of minimizing errors due to hydrostatic pressure differences across the membrane. In resting axons an Lp of 0.236 x 10-8 cm/ sec per cm H2O was found and similar values were obtained with low external calcium concentration and when the nerve was continuously stimulated at 20–30 impulses/sec. Thus the experiments have failed to demonstrate any change of water permeability in cases in which the ionic conductance is known to change. Some possible implications of this are discussed.

19. Intracellular freezing behavior under conditions of altered water permeability and initial cell volume

Cryobiology ◽  
2007 ◽  
Vol 55 (3) ◽  
pp. 329-330
Author(s):  
Ken Muldrew ◽  
Chris Barnsdale ◽  
Joel Lockwood ◽  
Richard Wan
Keyword(s):  
Cell Volume ◽  
Water Permeability ◽  
Freezing Behavior ◽  
Initial Cell

The effect of pH and ABA on the hydraulic conductivity of Nitella membranes

1977 ◽  
Vol 55 (1) ◽  
pp. 1-4 ◽  
Author(s):  
G. N. St.G. Ord ◽  
I. F. Cameron ◽  
D. S. Fensom
Keyword(s):  
Hydraulic Conductivity ◽  
Hydraulic Permeability ◽  
Effect Of Ph ◽  
Transcellular Osmosis

The method of transcellular osmosis was used to compare the hydraulic permeability (LP) of Nitella membranes at different pH's. LP did not change when the pH ranged from 5.0 to 7.0 but dropped slightly when the pH was 4.4 or below. Tris(hydroxymethyl)aminomethane buffer and abscissic acid (ABA) both increased LP significantly.

Sign in / Sign up

Export Citation Format

Share Document