It is generally believed that sphingomyelin- and cholesterol-enriched microdomains can be isolated as detergent-resistant membranes (DRMs) from plasma membrane and organelle membranes. Here, we describe the isolation and characterization of microdomains from sarcoplasmic reticulum (SR) membranes. These SR-derived detergent-resistant membranes (SR-DRMs) enriched in sphingomyelin and cholesterol ...

Purified plasma membrane fractions from lactating bovine mammary glands and membranes of milk fat globules from the same source were similar in distribution and fatty acid composition of phospholipids. The sphingomyelin content of the phospholipid fraction of both membranes was higher than in these fractions from other cell components, beta-carotene, a constituent characteristic of milk fat, wa...

Biologically active preparations of 125I-thyrotropin, [3H]thyrotropin, and the [3H]exophthalmogenic factor derived from thyrotropin by partial pepsin digestion have been used to study the binding properties of the thyrotropin receptor on guinea pig retro-orbital tissue plasma membranes. In regard to the optimal conditions of binding, pH, buffer, salt concentrations, and temperature, these prope...

Purified plasma membranes, smooth and rough endoplasmic reticulum, and nuclei were prepared from the livers of rats made either hyperinsulinemic with insulin injections or hypoinsulinemic with streptozotocin. Plasma membranes from insulin-treated animals bound 46% less lz51-insulin, and membranes from diabetic animals 33% more labeled hormone, than membranes from controls. Binding plots indicat...

Peak-to-peak distances between two dense lines of the unit membranes of cell organelles were measured on electron micrographs. These distances were compared with corresponding measurements on the plasma membrane and assigned a percentage value. The comparison between organelle and plasma membrane was always carried out with the same negative, in order to exclude as far as possible errors due to...

The effect of the local anesthetic dibucaine on the membrane ultrastructure of sterol-manipulated Tetrahymena pyriformis (NT-1 strain) was studied by freeze-fracture electron microscopy. Dibucaine-treated, ergosterol-replaced Tetrahymena cells had marked alterations in their plasma membranes. IMP-free small depressions (exoplasmic fracture face) and protrusions (protoplasmic fracture face) were...

the gas separation performance of commercial ceramic titania and hybrid silica (hybsi®) membranes was assessed using the gas permeation and permporometry methods. results indicated that the hybsi® membranes have a hybrid surface containing regions covered by a polymeric matrix and others with inorganic pores. these membranes have high h2 selectivity, which increases significantly with temperatu...

Purified plasma membranes were prepared from L1210 ascites tumor cells and analyzed for their protein and carbohydrate composition. Conditions were developed for treating the isolated plasma membranes with Vibrio cholerae neuraminidase (VCN) so that 88% of the N-acetylneuraminic acid was removed without changing membrane proteins or other membrane carbohydrate constituents. The VCN-induced modi...