gramicidin-a and primycin

In this paper the authors present a comparative study of the actions of the antibiotics primycin and gramicidin on the erythrocyte membrane permeability. It has been found that both antibiotics have a nonlinear effect on the membrane permeability. Above a threshold antibiotic concentration, which is characteristic of the type of the antibiotic, the cation permeability of the erythrocyte membranes increases sharply. In the range of nonlinearity the transport-kinetic curves level off before achieving the equilibrium radioactive ion distribution between the extra- and intracellular spaces. A stochastic model of the cooperative and aspecific incorporation of antibiotic molecules into the membrane explains the experimental findings. The authors conclude that membrane permeability increases at the places where two or more antibiotic molecules form aggregates in the membrane.

Topics: Anti-Bacterial Agents; Biological Transport; Cations; Cesium Radioisotopes; Chemical Phenomena; Chemistry; Erythrocyte Membrane; Extracellular Space; Gramicidin; Hematocrit; Humans; In Vitro Techniques; Kinetics; Macrolides; Models, Biological; Potassium Radioisotopes; Rubidium Radioisotopes

Data are presented on the interaction of gramicidin, primycin and valinomycin with red blood cell membranes and compared with those obtained for artificial lipid bilayer membranes. The channel forming antibiotics gramicidin and primycin show specific kinetic behaviour in living cell membranes. It could be shown that the penetration of these antibiotics into the red blood cell membrane is a cooperative process resulting in the occurrence of aggregates in the lipid lattice of the membrane.

Topics: Anti-Bacterial Agents; Erythrocyte Membrane; Gramicidin; Humans; Ion Channels; Kinetics; Lactones; Lipid Bilayers; Macrolides; Models, Biological; Valinomycin

A comparative study of the actions of antibiotics primycin and gramicidin on tracer exchange of red blood cells at steady state salt distribution was carried out. The equilibrium radioactive ion distribution was not achieved at definite concentrations of either antibiotics. A development of Adam's statistical mechanical model for cooperative transitions in membranes are presented to explain the results obtained.

Topics: Anti-Bacterial Agents; Biological Transport, Active; Cations; Cesium; Erythrocytes; Gramicidin; Humans; Kinetics; Lactones; Macrolides; Mathematics; Models, Biological; Potassium; Rubidium