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Biomedical subjects

G N Ling

Publications and source records attributed to G N Ling.

At least 91 records · Page 5Linked to original sources
PubMed1977

K+ localization in muscle cells by autoradiography, and identification of K+ adsorbing sites in living muscle cells with uranium binding sites in electron micrographs of fixed cell preparations.

Localization of K+-adsorption sites on two peripheral regions of the A band and the Z line in frog voluntary muscle cells has been demonstrated with the aid of autoradiography and radioactive 134Cs and 204 Tl. The findings confirm the association-induction hypothesis, according to which intracellular K+ is adsorbed on the beta- and gamma-carboxyl groups of intracellular proteins.

Adsorption↗
PubMed1976

What retains water in living cells?

Three types of evidence are presented showing that the retention of cell water does not necessarily depend on the possession of an intact cell membrane. The data agree with the concept that water retention in cells is due to multilayer adsorption on proteins and that the maintenance of the normal state of water relies on the presence of adenosine triphosphate as a cardinal adsorbent, controlling the protein conformations.

Adenosine Triphosphate↗
PubMed1976

Studies on insulin action. V. Structural requirements of primers for subsequent accumulation of D-glucose at 0 degrees C in insulinized frog muscles.

Systematic analysis was made of structural requirements for possible priming action of D-glucose and 40 related compounds in the presence of insulin to enhance subsequent labeled D-glucose uptake at 0 degrees C. It was concluded that a major portion if not all of the H-bonding groups on the D-glucose molecules are involved although their relative importance varies. Free OH and H on C-1, and upward orientation of OH and downward orientation of H on C-3, are the most important. Orientation of OH, H, and CH2OH on C-2, C-4, and C-5 are also important, but their perturbations are not nearly as detrimental to the priming action as those on C-1 and C-3.

Animals↗
PubMed1976

Na+ and K+ levels in living cells: do they depend on the rate of outward transport of Na+?

At 25 degrees C, frog sartorius muslces rapidly gained Na+ and lost K+ in iodoacetamide and pure nitrogen. Beginning at normal levels, the concentrations of these ions in the cells reached those in the surrounding Ringer solution in 140 min. Yet during that time the Na+ efflux rate showed no sign of the slowing down demanded by Na-pump theory. The data support the view that maintenance and alterations of N1+ levels in frog muslce cells reflect adsorption on protein sites and the solubility property of bulk phase water and are independent of the rate at which Na+ leaves the cell surface.

Animals↗
PubMed1975

Simultaneous efflux of K+ and Na+ from frog sartorius muscle freed of extracellular fluids: evidence for rapidly exchanging Na+ from the cells.

After removal of radioactivity trapped in the extracellular space and correcting for the contribution of connective tissue elements, the K+ -efflux curve of frog sartorius muscles becomes a perfect straight line in a semilogarithmic plot. The simultaneously recorded Na+-efflux curve from the same muscles remains strongly curved, and can be resolved into a slow fraction (which conventionally has been regarded as representing the entire cell Na+) and at least one fast fraction. The fast fraction of Na+ could not have originated from a sarcoplasmic reticulum or any other extracellular space extensions; otherwise a similar fast fraction should exist for K+. The data agree with the interpretation that it is the fast fraction that is rate limiting by cell permeability and the slow fraction by desorption from intracellular adsorption sites.

Adsorption↗
PubMed1975

The mechanism for the exclusion of sugars from the water in a model of the liveing cell: the ion-exchange resin: pore size or water structure?

The equilibrium distribution coefficients (p-value) of D-arabinose between the water in sulfonate ion-exchange resin and the external aqueous solution vary with the nature of the five alkali metal counterions studied. The strongest exclusion (lowest p-value) is found in the Li+ resin and the least exclusion (highest p-value) in the Cs+ resin. The p-value decreases with the increasing atomic weights for the alkali-metal ions: pCs+ greater than or equal to pRb+ greater than or equal to pRb+ greater than or equal to pK+ greater than pNa+ greater than pLi+. The water contents of these resins, on the other hand, vary in the opposite direction, being highest for the Li+ resin and lowest for the Cs+ resin. These data disprove the pore size theory but fully substantiate the predictions of the association-induction hypothesis.

Arabinose↗
PubMed1973

Mobility of potassium ion in frog muscle cells, both living and dead.

The diffusion coefficient of potassium ion (DK) in frog muscles was studied by a new method. In normal cytoplasm DK averaged one-eighth of the value in the free solution. Arrest of metabolism or injury caused an increase in DK. In muscles killed with iodoacetate, DK rose to three-quarters of the value in free solution. The data support the association-induction hypothesis.

Animals↗
PubMed1973

What component of the living cell is responsible for its semipermeable properties? Polarized water or lipids?

A close correlation (r = +0.96) exists between the permeability (at 0 degrees , 4 degrees , and 25 degrees C) of H(2)O and nine other hydroxylic nonelectrolytes through reversed frog skin and through synthetic cellulose-acetate sheets. By the method of least squares, the data yield the following relation: log (P(frog skin)) = 0.9900 log (P(cellulose acetate)) -0.1659. Both the reversed frog skin and the cellulose-acetate sheets are semipermeable (while the lipoid membrane is not), showing higher permeability to water than to any other solute used in this series. The data offer support for the theory that it is not lipid, but water polarized in multilayers by cellular proteins, that provides the living cell with its selective surface barrier.

Alcohols↗