Studies on osmotic equilibrium and on the kinetics of osmosis in living cells by a diffraction method

PROTOPLASMA ◽  
1936 ◽  
Vol 25 (1) ◽  
pp. 157-158
Keyword(s):  
Diffraction Method ◽  
Living Cells ◽  
Osmotic Equilibrium ◽  
Kinetics Of

scholarly journals STUDIES ON OSMOTIC EQUILIBRIUM AND ON THE KINETICS OF OSMOSIS IN LIVING CELLS BY A DIFFRACTION METHOD

1935 ◽  
Vol 19 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Balduin Lucké ◽  
Martin G. Larrabee ◽  
H. Keffer Hartline
Keyword(s):  
Cell Surface ◽  
Osmotic Pressure ◽  
Diffraction Pattern ◽  
Monochromatic Light ◽  
Diffraction Method ◽  
Living Cells ◽  
Individual Variability ◽  
Concentration Difference ◽  
Osmotic Equilibrium ◽  
Kinetics Of

1. Osmotic equilibrium and kinetics of osmosis of living cells (unfertilized eggs of Arbacia punctulata) have been studied by a diffraction method. This method consists of illuminating a suspension of cells by parallel monochromatic light and measuring, by means of telescope and scale, the angular dimensions of the resulting diffraction pattern from which the average volume of the cells may be computed. The method is far less laborious and possesses several advantages over direct measurement of individual cells. The average size of a large number of cells is obtained from a single measurement of the diffraction pattern and thus individual variability is averaged out. The observations can be made at intervals of a few seconds, permitting changes in volume to be followed satisfactorily. During the measurements the cells are in suspension and are constantly stirred. 2. Volumes of cells in equilibrium with solutions of different osmotic pressure have been determined. In agreement with our previous experiments, based upon direct microscope measurements, we have confirmed the applicability of the law of Boyle-van't Hoff to these cells; that is to say, the product of volume and pressure has been found to be approximately constant if allowance be made for the volume of osmotically inactive material of the cell contents. The volume of osmotically inactive material was found to be, on the average, 12 per cent of the initial cell volume; in eggs from different animals this value ranged from 6 to 20 per cent. 3. Permeability to water of the Arbacia egg has been found to average, at 22°C., 0.106 cubic micra of water per square micron of cell surface, per minute, per atmosphere of difference in osmotic pressure. 4. Permeability to ethylene glycol has been found to average, at 24°C., 4.0 x 10–15 mols, per square micron of cell surface, per minute, for a concentration difference of 1 mol per liter. This is in agreement with the values reported by Stewart and Jacobs.

scholarly journals THE KINETICS OF EXOSMOSIS OF WATER FROM LIVING CELLS

1927 ◽  
Vol 10 (5) ◽  
pp. 659-664 ◽  
Author(s):  
Morton McCutcheon ◽  
Baldwin Lucke
Keyword(s):  
Osmotic Pressure ◽  
Salt Concentration ◽  
Driving Force ◽  
Temperature Characteristic ◽  
Living Cells ◽  
Velocity Constant ◽  
Osmotic Equilibrium ◽  
Kinetics Of

1. The rate of exosmosis of water was studied in unfertilized Arbacia eggs, in order to bring out possible differences between the kinetics of exosmosis and endosmosis. 2. Exosmosis, like endosmosis, is found to follow the equation See PDF for Equation, in which a is the total volume of water that will leave the cell before osmotic equilibrium is attained, x is the volume that has already left the cell at time t, and k is the velocity constant. 3. The velocity constants of the two processes are equal, provided the salt concentration of the medium is the same. 4. The temperature characteristic of exosmosis, as of endomosis, is high. 5. It is concluded that the kinetics of exosmosis and endosmosis of water in these cells are identical, the only difference in the processes being in the direction of the driving force of osmotic pressure.

An infrared assay of the kinetics of phosphate-release from physiological substrates in living cells

2014 ◽  
Author(s):  
Ren Zhongyuan ◽  
Do Leduy ◽  
Saida Mebarek ◽  
Nermin Keloglu ◽  
Saandia Ahamada ◽  
...  
Keyword(s):  
Living Cells ◽  
Phosphate Release ◽  
Kinetics Of ◽  
Physiological Substrates

Spectrochemical Behavior of Carcinogenic Polycyclic Aromatic Hydrocarbons in Biological Systems. Part II: A Theoretical Rate Model for BaP Metabolism in Living Cells

1996 ◽  
Vol 50 (11) ◽  
pp. 1352-1359 ◽  
Author(s):  
Ping Chiang ◽  
Kuang-Pang Li ◽  
Tong-Ming Hseu
Keyword(s):  
Rate Constant ◽  
Living Cells ◽  
Rate Model ◽  
Number Density ◽  
Order Process ◽  
Irreversible Reaction ◽  
First Order ◽  
Metabolism Rate ◽  
Polycyclic Aromatic ◽  
Kinetics Of

An idealized model for the kinetics of benzo[ a]pyrene (BaP) metabolism is established. As observed from experimental results, the BaP transfer from microcrystals to the cell membrane is definitely a first-order process. The rate constant of this process is signified as k1. We describe the surface–midplane exchange as reversible and use rate constants k2 and k3 to describe the inward and outward diffusions, respectively. The metabolism is identified as an irreversible reaction with a rate constant k4. If k2 and k3 are assumed to be fast and not rate determining, the effect of the metabolism rate, k4, on the number density of BaP in the midplane of the microsomal membrane, m3, can be estimated. If the metabolism rate is faster than or comparable to the distribution rates, k2 and k3, the BaP concentration in the membrane midplane, m3, will quickly be dissipated. But if k4 is extremely small, m3 will reach a plateau. Under conditions when k2 and k3 also play significant roles in determining the overall rate, more complicated patterns of m3 are expected.

scholarly journals SIMILARITY OF THE KINETICS OF INVERTASE ACTION IN VIVO AND IN VITRO. II

1932 ◽  
Vol 16 (2) ◽  
pp. 233-242 ◽  
Author(s):  
B. G. Wilkes ◽  
Elizabeth T. Palmer
Keyword(s):  
Physiological Activity ◽  
Outer Region ◽  
Living Cells ◽  
Yeast Cells ◽  
Live Cells ◽  
Intracellular Enzyme ◽  
Relationship Of ◽  
Kinetics Of

1. The pH-activity relationship of invertase has been studied in vivo and in vitro under identical external environmental conditions. 2. The effect of changing (H+) upon the sucroclastic activity of living cells of S. cerevisiae and of invertase solutions obtained therefrom has been found, within experimental error, to be identical. 3. The region of living yeast cells in which invertase exerts its physiological activity changes its pH freely and to the same extent as that of the suspending medium. It is suggested that this may indicate that this intracellular enzyme may perform its work somewhere in the outer region of the cell. 4. In using live cells containing maltase, no evidence of increased sucroclastic activity around pH 6.9, due to the action of Weidenhagen's α-glucosidase (maltase), was found.

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