scholarly journals Rearrangements of integral membrane components during in vitro aging of sheep erythrocyte membranes

1977 ◽  
Vol 74 (2) ◽  
pp. 389-398 ◽  
Author(s):  
HU Lutz ◽  
AJ Lomant ◽  
P McMillan ◽  
E Wehrli
Keyword(s):  
Membrane Proteins ◽  
Particle Density ◽  
Sheep Erythrocyte ◽  
Freeze Fracture ◽  
Erythrocyte Membranes ◽  
Intramembranous Particles ◽  
In Vitro Aging ◽  
Membrane Components ◽  
Fracture Electron

In vitro aged sheep erythrocytes and sheep erythrocyte ghosts spontaneously release vesicles that consist of long protrusions affixed to flattened headlike structures. The intramembranous particles seen on the protoplasmic face of freeze fracture electron micrographs of vesicle protrusions are arranged in paired particle rows. On the equivalent fracture face of headlike structures, the particle density is low; if particles are present, they are clustered along the rim of the flattened headlike structure and at the junction with the protrusion. The released vesicles are depleted of the intramembranous particles seen on the exoplasmic face of ghost but retain almost exclusively particles of the protoplasmic face. Correspondingly, the exoplasmic face of ghosts that have released vesicles reveals a 28 percent higher density of intramembranous particles than that of fresh ghosts. Purified vesicles are depleted of spectrin but retain integral membrane proteins, with one of an apparent mol wt of 160,000 accounting for nearly 50 percent of the total protein (Lutz, H.U.,R. Barber, and R.F. McGuire. 1976. J. Biol. Chem. 251:3500-3510). When vesicles are modified with the cleavable cross-linking reagent [(35)S]dithiobis (succinimidyl propionate)at 0 degrees C, the 160,000 mol wt protein is rapidly converted to disulfide-linked dimers and higher oligomers. Exposure of intact ghosts to the reagent in the same way fails to yield equivalent polymers. A comparison of the morphological and biochemical aspects of ghosts and vesicles suggest that a marked rearrangement of membrane proteins accompanies the supramolecular redistribution of intramembranous particles during spontaneous vesiculation. The results also suggest that the paired particles of the protoplasmic face of vesicle protrusions are arranged in paired helices and contain the 160,000 mol wt protein as dimers.

External electrostatic field induced changes of rat erythrocyte membranes

2015 ◽  
Vol 34 (4) ◽  
pp. 1054-1062
Author(s):  
G.V. Sahakyan ◽  
G.G. Artsruni ◽  
G.A. Poghosyan
Keyword(s):  
Membrane Proteins ◽  
Electrostatic Field ◽  
Membrane Surface ◽  
Erythrocyte Membranes ◽  
Physical Parameters ◽  
Content Type ◽  
Membrane Components ◽  
Induced Changes

Purpose – The purpose of this paper was to reveal the possible changes in membrane physical parameters, such as surface charge, ξ-potential and molecular interactions of membrane components due to the in vitro and in vivo influences of ESF. Design/methodology/approach – The in vitro and in vivo (one hour) influences of 200 kV/m external electrostatic field (ESF) on the erythrocyte membranes of white outbred rats were investigated by spectrofluorometric, spectral and electrophoretic methods. Findings – It was shown that the in vivo influence of ESF leads to the intermolecular reconstructions and decrease of the positive charged groups in membrane surface layer. At the same time, the increases of the negative charged groups of membrane proteins after the field influence, is revealed. The charge redistribution in membranes due to the in vitro influence of ESF is observed. Originality/value – The analysis of literature data and generalization of data obtained allow us concluding that in parallel with the polarization of lipid component of bilayer the changes in the structural state of membrane proteins take place due to the ESF influence on the erythrocyte membranes. These changes can be the reason and/or the result of the ESF induced redistribution of membrane charge.

Image Analysis of Intramembrane Particles in Freeze-Fractured Biomembranes Using Computer Simulation Techniques

1975 ◽  
Vol 33 ◽  
pp. 214-215
Author(s):  
D.J. Benefiel ◽  
R.S. Weinstein
Keyword(s):  
Membrane Proteins ◽  
Freeze Fracture ◽  
Integral Membrane Proteins ◽  
Systematic Evaluation ◽  
Intramembrane Particles ◽  
Modeling Methods ◽  
Simulation Techniques ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron ◽  
Computer Simulation Techniques

Intramembrane particles (IMP or MAP) are components of most biomembranes. They are visualized by freeze-fracture electron microscopy, and they probably represent replicas of integral membrane proteins. The presence of MAP in biomembranes has been extensively investigated but their detailed ultrastructure has been largely ignored. In this study, we have attempted to lay groundwork for a systematic evaluation of MAP ultrastructure. Using mathematical modeling methods, we have simulated the electron optical appearances of idealized globular proteins as they might be expected to appear in replicas under defined conditions. By comparing these images with the apearances of MAPs in replicas, we have attempted to evaluate dimensional and shape distortions that may be introduced by the freeze-fracture technique and further to deduce the actual shapes of integral membrane proteins from their freezefracture images.

scholarly journals Reversible particle movements associated with unstacking and restacking of chloroplast membranes in vitro.

1976 ◽  
Vol 71 (1) ◽  
pp. 136-158 ◽  
Author(s):  
L A Staehelin
Keyword(s):  
Plasma Membranes ◽  
Structural Changes ◽  
Freeze Fracture ◽  
Chloroplast Membranes ◽  
Ps Ii ◽  
Membrane Particles ◽  
Intramembranous Particles ◽  
Membrane Surfaces ◽  
Ps Ii Activity

Freeze-fracture and freeze-etch techniques have been employed to study the supramolecular structure of isolated spinach chloroplast membranes and to monitor structural changes associated with in vitro unstacking and restacking of these membranes. High-resolution particle size histograms prepared from the four fracture faces of normal chloroplast membranes reveal the presence of four distinct categories of intramembranous particles that are nonrandomly distributed between grana and stroma membranes. The large surface particles show a one to one relationship with the EF-face particles. Since the distribution of these particles between grana and stroma membranes coincides with the distribution of photosystem II (PS II) activity, it is argued that they could be structural equivalents of PS II complexes. An interpretative model depicting the structural relationship between all categories of particles is presented. Experimental unstacking of chloroplast membranes in low-salt medium for at least 45 min leads to a reorganization of the lamellae and to a concomitant intermixing of the different categories of membrane particles by means of translational movements in the plane of the membrane. In vitro restacking of such experimentally unstacked chloroplast membranes can be achieved by adding 2-20 mM MgCl2 or 100-200 mM NaCl to the membrane suspension. Membranes allowed to restack for at least 1 h at room temperature demonstrate a resegregation of the EF-face particles into the newly formed stacked membrane regions to yield a pattern and a size distribution nearly indistinguishable from the normally stacked controls. Restacking occurs in two steps: a rapid adhesion of adjoining stromal membrane surfaces with little particle movement, and a slower diffusion of additional large intramembranous particles into the stacked regions where they become trapped. Chlorophyll a:chlorophyll b ratios of membrane fraction obtained from normal, unstacked, and restacked membranes show that the particle movements are paralleled by movements of pigment molecules. The directed and reversible movements of membrane particles in isolated chloroplasts are compared with those reported for particles of plasma membranes.

In vitro human skin barrier perturbation by oleic acid: Thermal analysis and freeze fracture electron microscopy studies

1997 ◽  
Vol 293 (1-2) ◽  
pp. 77-85 ◽  
Author(s):  
Hanafi Tanojo ◽  
Anita Bos-van Geest ◽  
Joke A. Bouwstra ◽  
Hans E. Junginger ◽  
Harry E. Boodé
Keyword(s):  
Electron Microscopy ◽  
Thermal Analysis ◽  
Oleic Acid ◽  
Human Skin ◽  
Freeze Fracture ◽  
Skin Barrier ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron

scholarly journals Changes in erythrocyte membrane proteins during in vitro aging

1987 ◽  
Vol 43 ◽  
pp. 95
Author(s):  
Kenji Yamamoto ◽  
Miho Yamada ◽  
Eiko Ueno ◽  
Haruki Uemura ◽  
Yuzo Kato
Keyword(s):  
Membrane Proteins ◽  
Erythrocyte Membrane ◽  
In Vitro Aging ◽  
Erythrocyte Membrane Proteins

The mobility and reactivity of maleimide-binding proteins in the rat erythrocyte membrane. Effects of dietary zinc deficiency and incubation with zinc in vitro

1988 ◽  
Vol 66 (1) ◽  
pp. 66-71 ◽  
Author(s):  
Stan J. Kubow ◽  
William J. Bettger
Keyword(s):  
Membrane Proteins ◽  
Erythrocyte Membrane ◽  
Zinc Deficiency ◽  
Binding Proteins ◽  
Thermal Sensitivity ◽  
Erythrocyte Membranes ◽  
Resonance Spectroscopy ◽  
Dietary Zinc ◽  
Membrane Effects

Erythrocyte ghosts, prepared from rats fed zinc-deficient diets, were analyzed for the mobility of membrane proteins by electron spin resonance spectroscopy of the sulfhydryl-binding spin probe, 4-maleimido-2,2,6,6-tetramethylpiperidine-N-oxyl. Compared with erythrocyte membranes from rats fed zinc-adequate diets ad libitum or pair-fed, erythrocyte membranes from zinc-deficient rats had a significantly increased ratio of weakly immobilized to strongly immobilized probe-binding proteins. This suggests that dietary zinc deficiency causes a conformational change in erythrocyte membrane proteins. Dietary zinc deficiency did not significantly affect N-ethylmaleimide (NEM)-induced thermal sensitivity or NEM-induced mechanical fragility in rat erythrocytes; however, the addition of zinc in vitro to red cells significantly inhibits NEM-induced mechanical fragility.

scholarly journals Studies on the mechanism of polyethylene glycol-mediated cell fusion using fluorescent membrane and cytoplasmic probes.

1983 ◽  
Vol 96 (1) ◽  
pp. 151-159 ◽  
Author(s):  
J W Wojcieszyn ◽  
R A Schlegel ◽  
K Lumley-Sapanski ◽  
K A Jacobson
Keyword(s):  
Polyethylene Glycol ◽  
Cell Fusion ◽  
Cultured Cells ◽  
Membrane Lipids ◽  
Freeze Fracture ◽  
Water Soluble ◽  
Erythrocyte Membranes ◽  
Adjacent Cell ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron

The mechanism by which polyethylene glycol (PEG) mediates cell fusion has been studied by examining the movements of membrane lipids and proteins, as well as cytoplasmic markers, from erythrocytes to monolayers of cultured cells to which they have been fused. Fluorescence and freeze-fracture electron microscopy and fluorescence recovery after photobleaching have yielded the following results: (a) In the presence of both fusogenic and nonfusogenic PEG membranes are brought together at closely apposed contact regions. (b) Fluorescent lipid probes quickly spread from the membranes of erythrocytes to cultured cells in the presence of both fusogenic and nonfusogenic PEG. (c) Proteins of the erythrocyte membranes were never observed to diffuse into the cultured cell membrane. (d) Water-soluble proteins did not diffuse from the erythrocyte interior into the target cell cytoplasm until the PEG was removed. These data suggest that the coordinate action of two distinct components is necessary for fusion as mediated by PEG. Presumably, the polymer itself promotes close apposition of the adjacent cell membranes but the fusion stimulus is provided by the additives contained in commercial PEG.

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