Scanning Microscopy


Nonionic detergents, Triton X-100 and Brij 58, removed, within 2-5 minutes, lipid membrane of suspended thymus lymphocytes and monolayer H-50 cells grown in culture. Studies of hydration, ionic asymmetry, and ionic and protein release kinetics were conducted on these membraneless cellular preparations. The hydration of nuclei isolated by Triton X-100 procedures appears to be influenced strongly by the monovalent ionic concentration of the buffer bathing the organelles. The putative monovalent ionic concentration of the cellular aqueous phase (i.e., 150 meq/L) caused nuclei to swell and coalesce. Monovalent ionic concentrations of 30 meq/L or less caused minimal changes in volume and in morphology. Triton X-100 treatment led to rapid mobilization and solubilization of membrane and cytoplasmic lipids and proteins, and the cellular potassium was reduced to very low levels. Brij 58 treatment of the lymphocytes for 5 minutes led to loss of membrane structure. Potassium, however, was retained at significant levels for over 10 minutes. Potassium and protein release kinetic studies in the H-50 monolayer cells following Brij treatment revealed that potassium and the detergent mobilized proteins may be co-compartmentalized and that 10 minutes or more are required before their release is completed. These results support the view that most of the potassium and "diffusible" proteins are not fully dissolved in the cellular water. Furthermore, the integrity of the membranes does not appear to be essential for the retention of the ions and the proteins.

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