The permeability of red cells to water and ions

Cation transport in Escherichia coli. II. Intracellular chloride concentration

The intracellular Cl concentration in E. coli has been studied as a function of the Cl concentration in the growth medium and the age of the bacterial culture. The ratio of extracellular to intracellular Cl concentration is shown to be 3.0 in the logarithmic phase and 1.13 in the stationary phase, both ratios being independent of the extracellular Cl concentration. If it may be assumed that Cl is passively distributed in this organism, these results are consistent with a transmembrane P.D. of 29 mv, interior negative, during the logarithmic phase, and 3 mv, interior negative, in the stationary phase.

Effect of antibody and complement on permeability control in ascites tumor cells and erythrocytes

Rabbit antibody + complement alters the permeability properties of mouse Krebs ascites tumor cells and erythrocytes. When antibody + C' acts on ascites tumor cells in a low protein medium, intracellular K⁺ is lost from the cells at a rate far greater than the normal leak rate. At the same time the cells lose amino acids and ribonucleotides and become fully permeable to the Na⁺ of the medium. When antibody + C' acts in a low protein medium, the cells swell extensively and lose most of their macromolecules to the medium (hemoglobin from erythrocytes, protein and RNA from the ascites tumor cells). If the antibody + C' acts in a medium containing protein in sufficient concentration to balance the colloid osmotic pressure of the cells, the swelling is prevented; no macromolecules are then lost from the cells, but the loss of K⁺ and entrance of Na⁺ are not altered, and the loss of amino acids and ribonucleotides is only slightly affected. It therefore appears that the action of antibody + C' is to produce functional "holes" in the animal cell membrane which permit the equilibration of cations and small molecules between cell and medium. This leads to an increase in the osmotic pressure of the cell and a rapid influx of water. The cell membrane and its "holes" are thereby stretched, permitting macromolecules to escape from the cell.