The process of infection of lupin nodule cells by rhizobia was examined using thin-section and freeze-fracture electron-microscopic techniques to characterize the properties of different membranes and to establish relationships between them. The membranes of the Golgi bodies and the endoplasmic reticulum stained with zinc iodide-osmium tetroxide but not with phosphotungstic acid or silver. By c...

The apical plasma membrane of differentiated superficial urothelial cells is characterised by the presence of asymmetric unit membrane (AUM). Cyclophosphamide (CP) metabolites cause perforation of these thickened membranes. In this study, apical plasma membranes were examined after CP injection by electron microscopy. The immediate effect of the CP metabolites was observed as small round holes ...

The cell surface complex (Detering et al., 1977, J. Cell Biol. 75, 899-914) of the sea urchin egg consists of two subcellular organelles: the plasma membrane, containing associated peripheral proteins and the vitelline layer, and the cortical vesicles. We have now developed a method of isolating the plasma membrane from this complex and have undertaken its biochemical characterization. Enzymati...

We have utilized wheat germ agglutinin conjugated to iron/dextran particles in conjunction with high gradient magnetic affinity chromatography (HIMAC) to prepare plasma membranes from cultured cells. Membrane-impermeable succinimidyl esters inactivate alkaline phosphodiesterase 1 (APDE-1) and were used to establish the proportion of APDE-1 expressed at the cell surface. The yield of inhibitable...

Both thyroid-stimulating hormone (TSH) and long-acting thyroid stimulator (LATS) stimulated adenyl cyclase activity in plasma membranes obtained from bovine thyroid glands. The stimulation induced by LATS was much less than that obtained with maximal amounts of TSH. LATS inhibited TSH stimulation of adenyl cyclase activity while an equivalent amount of normal human gamma-globulin did not influe...

Eukaryotic cell membranes are organized into functional lipid and protein domains, the most widely studied being membrane rafts. Although rafts have been associated with numerous plasma membrane functions, the mechanisms by which these domains themselves are regulated remain undefined. Bile acids (BAs), whose primary function is the solubilization of dietary lipids for digestion and absorption,...

The membranes of Acanthamoeba palestinensis were studied by examination in fixed cells, and then by following the movements of glycerol-(3)H-labeled phospholipids by cell fractionation. Two previously undescribed structures were observed: collapsed cytoplasmic vesicles of cup shape, and plaques in food vacuole and plasma membrane similar in size to the collapsed vesicles. It appeared that the p...