Dimyristoylphosphatidylcholine (DMPC) particles of different sizes were prepared by a short sonication of the lipid followed by fractionation on a Sepharose CL-4B column. Column fractions were pooled to give DMPC multilamellar liposomes, and vesicles ranging in average diameters from 300 to 220 A. These particles were used to prepare complexes with bovine apolipoprotein A-I (apo A-I). Reaction ...

Depending on their phospholipid composition, liposomes are endocytosed by, or fuse with, the plasma membrane, of Acanthamoeba castellanii. Unilamellar egg lecithin vesicles are endocytosed by amoeba at 28 degrees C with equal uptake of the phospholipid bilayer and the contents of the internal aqueous space of the vesicles. Uptake is inhibited almost completely by incubation at 4 degrees C or ...

The push-pull solvatochromic pyrene derivatives PA and PK have been applied to the study of model membrane vesicles, cells purified human serum lipoproteins, using both confocal fluorescence microscopy spectroscopy. These polarity-sensitive probes provide information similar that obtained by Laurdan or Prodan, i.e. mainly lipid order in biomembranes, but they essential advantage being excitable...

We have used computer-assisted reconstructions of continuous serial sections to study the cytoplasmic organization of growth cones in vivo. Optic tecta from 6.25-6.5-d-old chicken embryos were quick-frozen and then freeze-substituted in acetone-osmium tetroxide or, for comparison, prepared by conventional fixation. Images of eight freeze-substituted and two conventionally fixed growth cones wer...

Disruption of autophagy leads to accumulation of intracellular multilamellar inclusions morphologically similar to organised smooth endoplasmic reticulum (OSER) membranes. However, the relation of these membranous compartments to autophagy is unknown. The purpose of this study was to test whether OSER plays a role in the autophagic protein degradation pathway. Here, GFP-LC3 is shown to localise...

Detergent-resistant membrane raft fractions have been prepared from human, goat, and sheep erythrocyte ghosts using Triton X-100. The structure and thermotropic phase behaviour of the fractions have been examined by freeze-fracture electron microscopy and synchrotron X-ray diffraction methods. The raft fractions are found to consist of vesicles and multilamellar structures indicating considerab...

UNLABELLED All positive-strand RNA viruses induce membrane structures in their host cells which are thought to serve as suitable microenvironments for viral RNA synthesis. The structures induced by enteroviruses, which are members of the family Picornaviridae, have so far been described as either single- or double-membrane vesicles (DMVs). Aside from the number of delimiting membranes, their ex...

The experiments reported here were designed to test the hypothesis that the two-electron quinone reductase DT-diaphorase [NAD(P)H:(quinone-acceptor) oxidoreductase, EC 1.6.99.2] functions to maintain membrane-bound coenzyme Q (CoQ) in its reduced antioxidant state, thereby providing protection from free radical damage. DT-diaphorase was isolated and purified from rat liver cytosol, and its abil...