scholarly journals Optical-rotatory-dispersion studies of compounds related to cholesterol in liposomes and the membranes of erythrocyte ‘ghosts’

1973 ◽  
Vol 135 (1) ◽  
pp. 63-71 ◽  
Author(s):  
Jonathan R. Green ◽  
Peter A. Edwards ◽  
Colin Green
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Optical Rotatory Dispersion ◽  
Rotatory Dispersion ◽  
Erythrocyte Membranes ◽  
Optical Rotatory ◽  
Erythrocyte Ghosts ◽  
Polar Solvents ◽  
Human Erythrocyte Membranes ◽  
Do So

1. Steroid molecules containing the α,β-unsaturated oxo group in various positions were incorporated with egg phosphatidylcholine into liposomes and into human erythrocyte membranes. 2. The liposomes formed contained 0.3–0.94mol of steroid/mol of phospholipid and the steroids replaced 19–76% of the erythrocyte membrane sterol. 3. The optical rotatory dispersion (o.r.d.) spectra of the steroids in these structures were compared with those obtained in solvents of different polarity. 4. The o.r.d. spectra of cholesta-4,6-dien-3-one and 3-hydroxycholest-3-en-2-one in liposomes resembled those obtained with polar solvents such as ethanol or triethyl phosphate–water (1:1, v/v). 5. The o.r.d. spectra of 3-hydroxycholest-7-en-6-one and 3-hydroxycholest-5-en-7-one in liposomes resembled those obtained with moderately polar solvents such as dioxan. 6. The o.r.d. spectrum of 3-hydroxycholest-8(14)-en-15-one in liposomes resembled those obtained with non-polar solvents such as cyclohexane. 7. 3-Hydroxycholest-3-en-2-one did not exchange with erythrocyte membrane cholesterol, but the other steroids did do so and the o.r.d. spectra of the membranes containing them closely resembled those obtained with liposomes. 8. From the results, the position of sterol molecules with respect to the phospholipid molecules in liposomes and membranes of human erythrocyte ‘ghosts’ can be deduced.

scholarly journals Membrane glycopeptides from old and young human erythrocytes (Short Communication)

1974 ◽  
Vol 140 (3) ◽  
pp. 557-560 ◽  
Author(s):  
Cesare Balduini ◽  
Carlo Luigi Balduini ◽  
Edoardo Ascari
Keyword(s):  
Sialic Acid ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Short Communication ◽  
Chemical Characterization ◽  
Erythrocyte Membranes ◽  
Main Peak ◽  
Human Erythrocyte Membranes ◽  
Papain Digestion

Glycopeptides were extracted by papain digestion from old and young human erythrocyte membranes and fractionated on DEAE-Sephadex A-25. Chemical characterization of the unfractionated samples and of the main peak eluted from the column indicates that glycoproteins of the erythrocyte membrane undergo significant decreases in sialic acid and galactosamine content with aging.

scholarly journals Electron microscope study of reassociation of spectrin and actin with the human erythrocyte membrane

1981 ◽  
Vol 90 (1) ◽  
pp. 70-77 ◽  
Author(s):  
S Tsukita ◽  
S Tsukita ◽  
H Ishikawa ◽  
S Sato ◽  
M Nakao
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Erythrocyte Membranes ◽  
Human Erythrocyte Membrane ◽  
Thin Sections ◽  
Fixation Treatment ◽  
Human Erythrocyte Membranes ◽  
Inside Out

Reassociation of spectrin and actin with human erythrocyte membranes was studied by stereoscopic electron microscopy of thin sections combined with tannic acid- glutaraldehyde fixation. Treatment of the erythrocyte membrane with 0.1 mM EDTA (pH 8.0) extracted more than 90 percent of the spectrin and actin and concomitantly removed filamentous meshworks underlying the membranes, followed by fragmentation into small inside-out vesicles. When such spectrin-depleted vesicles were incubated with the EDTA extract (crude spectrin), a filamentous meshwork, similar to those of the original membranes, was reformed on the cytoplasmic surface of the vesicles. The filamentous components, with a uniform thickness of 9 nm, took a tortuous course and joined one another often in an end-to-end fashion to form a irregular but continuous meshwork parallel to the membrane. Purified spectrin was also reassociated with the vesicles in a population density of filamentous components almost comparable to that of the crude spectrin-reassociated vesicles. However, the meshwork formation was much smaller in extent, showing many independent filamentous components closely applied to the vesicle surface. When muscle G-actin was added to the crude spectrin- or purified spectrin- reassociated vesicles under conditions which favor actin polymerization, actin filaments were seen to attach to the vesicles through the filamentous components. Two modes of association of actin filaments with the membrane were seen: end-to-membrane and side-to- membrane associations. In the end-to-membrane association, each actin filament was bound with several filamentous components exhibiting a spiderlike configuration, which was considered to be the unit of the filamentous meshwork of the original erythrocyte membrane.

Coisolation of glycophorin A and polyphosphoinositides from human erythrocyte membranes

1978 ◽  
Vol 56 (5) ◽  
pp. 349-351 ◽  
Author(s):  
J. Thomas Buckley
Keyword(s):  
Membrane Protein ◽  
Erythrocyte Membrane ◽  
Lipid Composition ◽  
Human Erythrocyte ◽  
Erythrocyte Membranes ◽  
Glycophorin A ◽  
Firm Conclusion ◽  
Membrane Phospholipids ◽  
Human Erythrocyte Membranes ◽  
Significant Enrichment

The lipid composition of purified erythrocyte membrane glycophorin was measured. Diphosphoinositide, triphosphoinositide, and phosphatidylserine are the major phospholipids in glycophorin preparations. Nearly all of the radioactive diphosphoinositide and triphosphoinositide extracted from erythrocyte membranes by lithium diiodosalicylate are recovered in purified glycophorin. There appeared to be no significant enrichment of other acidic membrane phospholipids in the protein. The results do not permit a firm conclusion as to whether the polyphosphoinositides are associated specifically with the membrane protein or whether fortuitous binding has occurred during purification.

scholarly journals Whole-grain rye and wheat alkylresorcinols are incorporated into human erythrocyte membranes

2005 ◽  
Vol 93 (1) ◽  
pp. 11-13 ◽  
Author(s):  
Anna-Maria Linko ◽  
Herman Adlercreutz
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Erythrocyte Membranes ◽  
Wheat Bread ◽  
Whole Grain ◽  
Phenolic Lipids ◽  
Human Erythrocyte Membranes ◽  
Wheat Products ◽  
Grain Products

Alkylresorcinols (AR), a group of phenolic lipids, exist in the human diet in whole-grain rye and wheat. They are absorbed by humans and have been quantified in plasma. In this 2-week study we assessed AR incorporation into human erythrocyte membranes. Nine subjects attended the study; four avoided whole-grain products for 1 week and then included whole-grain rye and wheat bread in the diet for the second week, four included whole-grain rye and wheat products in the diet during the whole follow-up and one followed a gluten-free diet. Plasma and erythrocyte membrane AR were analysed after weeks 1 and 2. Erythrocyte membrane AR concentrations increased an average of 231 nmol/l of packed erythrocytes (P=0·036) after consumption of whole-grain rye and wheat products. Plasma AR levels increased an average of 175 nmol/l (P=0·058) When intake of whole-grain products was constant, erythrocyte membrane and plasma AR levels remained stable. Long-chain AR were incorporated into erythrocyte membranes in a higher proportion compared to shorter-chain AR. This preliminary study shows that AR are incorporated into human erythrocyte membranesin vivo.

scholarly journals Identification of a sialoglycopeptide released by self-digestion from human erythrocyte membranes

1976 ◽  
Vol 158 (2) ◽  
pp. 497-500 ◽  
Author(s):  
A Brovelli ◽  
G Pallavicini ◽  
F Sinigaglia ◽  
C L Balduini ◽  
C Balduini
Keyword(s):  
Amino Acids ◽  
Chemical Composition ◽  
Human Erythrocyte ◽  
Molecular Size ◽  
Erythrocyte Membranes ◽  
Erythrocyte Ghosts ◽  
Human Erythrocyte Membranes

Membranes from human O Rhesus-positive erythrocyte ‘ghosts’ were tested in vitro for their ability to digest their own glycoproteins. ‘Ghost’ membranes incubated in Tris/HCl buffer, pH 7.4, release a sialoglycopeptide, which contains glucosamine, galactosamine, galactose and mainly polar amino acids. Chemical composition, molecular size and aggregation properties suggest that this glycopeptide may be a fragment of glycophorin.

scholarly journals Are polyphosphoinositides associated with glycophorin in human erythrocyte membranes?

1979 ◽  
Vol 179 (2) ◽  
pp. 441-444 ◽  
Author(s):  
S D Shukla ◽  
R Coleman ◽  
J B Finean ◽  
R H Michell
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Erythrocyte Membranes ◽  
Human Erythrocyte Membrane ◽  
Human Erythrocyte Membranes ◽  
Partition Method ◽  
Triton X

Glycophorin prepared by a lithium di-iodosalicylate-extraction/phenol-partition method was rich in polyphosphoinositides (phosphatidyl-myo-inositol 4-phosphate and phosphatidyl-myo-inositol 4,5-bisphosphate), but glycophorin extracted by Triton X-100 showed no such enrichment. The enrichment observed in the former preparations appeared not to be caused by pre-existing association between glycophorin and polyphosphoinositides in the human erythrocyte membrane, but to be largely a consequence of the preparative procedures.

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