scholarly journals Transmembrane migration (‘flip-flop’) of cholesterol in erythrocyte membranes

1977 ◽  
Vol 168 (3) ◽  
pp. 575-577 ◽  
Author(s):  
C J Kirby ◽  
C Green
Keyword(s):  
Bile Salt ◽  
Erythrocyte Membrane ◽  
Specific Radioactivity ◽  
Plasma Lipoproteins ◽  
Erythrocyte Membranes ◽  
Half Time ◽  
Salt Solutions ◽  
Flip Flop ◽  
Two Sides

After exchange with [14C]cholesterol-labelled plasma lipoproteins for 0.5-4h, erythrocytes were extracted with bile-salt solutions. The extracted cholesterol (mainly from the outside of the erythrocyte membrane) had the same specific radioactivity as the residual sterol. Thus cholesterol equilibrates rapidly (half-time less than 1 h) between the two sides of the membrane.

scholarly journals Transport of fluorescent phospholipid analogues from the erythrocyte membrane to the parasite in Plasmodium falciparum-infected cells.

1989 ◽  
Vol 108 (6) ◽  
pp. 2183-2192 ◽  
Author(s):  
K Haldar ◽  
A F de Amorim ◽  
G A Cross
Keyword(s):  
Plasmodium Falciparum ◽  
Erythrocyte Membrane ◽  
Infected Erythrocyte ◽  
Lucifer Yellow ◽  
Lipid Transport ◽  
Membrane Properties ◽  
Erythrocyte Membranes ◽  
Flip Flop ◽  
Host Membrane ◽  
Infected Cells

The asexual development of the human malaria parasite Plasmodium falciparum is largely intraerythrocytic. When 1-palmitoyl-2-[6-[(7-nitro-2-1,3-benzoxadiazole-4-yl)amino]caproyl] phosphatidylcholine (NBD-PC) was incorporated into infected and uninfected erythrocyte membranes at 0 degrees C, it remained at the cell surface. At 10 degrees C, the lipid was rapidly internalized in infected erythrocytes at all stages of parasite growth. Our results indicate that the internalization of NDB-PC was not because of endocytosis but rapid transbilayer lipid flip-flop at the infected erythrocyte membrane, followed by monomer diffusion to the parasite. Internalization of the lipid was inhibited by (a) depleting cellular ATP levels; (b) pretreating the cells with N-ethyl maleimide or diethylpyrocarbonate; and (c) 10 mM L-alpha-glycerophosphorylcholine. The evidence suggests protein-mediated and energy dependent transmembrane movement of the PC analogue. The conditions for the internalization of another phospholipid analogue N-4-nitrobenzo-2-oxa-1,3-diazoledipalmitoyl phosphatidylethanolamine (N-NBD-PE) were distinct from that of NBD-PC and suggest the presence of additional mechanism(s) of parasite-mediated lipid transport in the infected host membrane. In spite of the lack of bulk, constitutive endocytosis at the red cell membrane, the uptake of Lucifer yellow by mature infected cells suggests that microdomains of pinocytotic activity are induced by the intracellular parasite. The results indicate the presence of parasite-induced mechanisms of lipid transport in infected erythrocyte membranes that modify host membrane properties and may have important implications on phospholipid asymmetry in these membranes.

scholarly journals Effect of Hyperglycemia on the Total Surface Charge of the Erythrocyte Membrane in Patients with Metabolic Syndrome

2019 ◽  
Vol 15 (3) ◽  
pp. 322-327
Author(s):  
V. I. Podzolkov ◽  
T. V. Koroleva ◽  
M. G. Kudryavtseva
Keyword(s):  
Metabolic Syndrome ◽  
Surface Charge ◽  
Erythrocyte Membrane ◽  
Negative Charge ◽  
Fasting Blood Glucose ◽  
Microvascular Blood Flow ◽  
Erythrocyte Membranes ◽  
Vascular Changes ◽  
Group 2 ◽  
Group 1

Aim. To study the effect of hyperglycemia on the total surface charge of the erythrocyte membrane (SCEM) in patients with metabolic syndrome (MS).Material and methods. 112 MS patients were examined (45 men and 67 women) (mean age 61.4±7.2 years, average MS duration 8.7±5.2 years). The level of SCEM was determined by adsorption of a positive cationic dye (cationic blue O) on the surface of the plasma membrane of erythrocytes to completely neutralize their negative charge, followed by photometry of the solution and calculation of the number of charges on the cell surface of erythrocytes.Results. In the main group of patients with MS, abdominal obesity was observed in 100% of patients, arterial hypertension – in 73%, hyperglycemia – in 75%, dyslipidemia – in 80%. The level of glycated hemoglobin (HbA1c) was determined in all patients with MS, which was 7.3±1.9%. Patients with MS were conditionally divided according to the level of HbA1c into 2 groups (group 1 – HbA1c from 6.6 to 7.8%, group 2 – more than 7.8%). In MS patients with hyperglycemia, the SCEM values were significantly lower than in the group of patients without hyperglycemia (1.58±0.05×107 and 1.64±0.03×107, respectively; p=0.001)., Significant negative correlations between SCEM and the fasting blood glucose level, hyperglycemia duration, HbA1c level were found in patients with MS.Conclusion. SCEM indices reliably depended on the presence, severity and duration of hyperglycemia, which indicated the effect of impaired carbohydrate metabolism on the state of electric charge of erythrocyte membranes and, therefore, on the mechanisms of microvascular blood flow, thereby contributing to the development of vascular changes in patients with MS.

scholarly journals Multidrug resistance protein 1 regulates lipid asymmetry in erythrocyte membranes

2000 ◽  
Vol 350 (2) ◽  
pp. 531-535 ◽  
Author(s):  
David W. C. DEKKERS ◽  
Paul COMFURIUS ◽  
Rein G. J. VAN GOOL ◽  
Edouard M. BEVERS ◽  
Robert F. A. ZWAAL
Keyword(s):  
Multidrug Resistance ◽  
Erythrocyte Membrane ◽  
Erythrocyte Membranes ◽  
Multidrug Resistance Protein ◽  
Multidrug Resistance Protein 1 ◽  
Lipid Asymmetry ◽  
Appreciable Change ◽  
Outer Leaflet ◽  
Resistance Protein ◽  
Phospholipid Distribution

The role of multidrug resistance protein 1 (MRP1) in the maintenance of transbilayer lipid asymmetry in the erythrocyte membrane was investigated. The transbilayer distribution of endogenous phospholipids and [(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]hexanoyl (NBD)-labelled lipid analogues was compared in the absence and the presence of inhibitors of MRP1. At equilibrium the transbilayer distribution of the NBD analogues (in the absence of MRP1 inhibitors) was very similar to that of the endogenous lipids. Inhibition of MRP1 by verapamil or indomethacin resulted in a shift in the amount of probe that was internalized: approx. 50% of NBD-labelled phosphatidylcholine (PtdCho) and 9% of NBD-sphingomyelin (NBD-Spm) were no longer extractable by BSA in cells treated with inhibitor, in comparison with 25% and 3% for control cells respectively. To verify whether inhibition of MRP1 also affected the distribution of the endogenous phospholipids, phospholipase A2 and sphingomyelinase were used to assess the amount of each of the various lipid classes present in the membrane outer leaflet. No shift in phospholipid distribution was observed after 5h of incubation with verapamil or indomethacin. However, after 48h of incubation with these inhibitors, significantly smaller amounts of PtdCho and Spm were present in the outer membrane leaflet. No appreciable change was observed in the distribution of phosphatidylethanolamine or phosphatidylserine. Decreased hydrolysis of PtdCho and Spm was not due to endovesicle formation, as revealed by electron microscopy. This is the first report to show that MRP1 has a role in the maintenance of the outwards orientation of endogenous choline-containing phospholipids in the erythrocyte membrane.

scholarly journals Novel pathogenic XK mutations in McLeod syndrome and interaction between XK protein and chorein

2019 ◽  
Vol 5 (3) ◽  
pp. e328 ◽  
Author(s):  
Yuka Urata ◽  
Masayuki Nakamura ◽  
Natsuki Sasaki ◽  
Nari Shiokawa ◽  
Yoshiaki Nishida ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Erythrocyte Membrane ◽  
Molecular Analysis ◽  
Cultured Cells ◽  
Immunoblot Analysis ◽  
Erythrocyte Membranes ◽  
Onset Age ◽  
Novel Mutations ◽  
Erythrocyte Membrane Proteins ◽  
Normal Controls

ObjectiveTo identify XK pathologic mutations in 6 patients with suspected McLeod syndrome (MLS) and a possible interaction between the chorea-acanthocytosis (ChAc)- and MLS-responsible proteins: chorein and XK protein.MethodsErythrocyte membrane proteins from patients with suspected MLS and patients with ChAc, ChAc mutant carriers, and normal controls were analyzed by XK and chorein immunoblotting. We performed mutation analysis and XK immunoblotting to molecularly diagnose the patients with suspected MLS. Lysates of cultured cells were co-immunoprecipitated with anti-XK and anti-chorein antibodies.ResultsAll suspected MLS cases were molecularly diagnosed with MLS, and novel mutations were identified. The average onset age was 46.8 ± 8 years, which was older than that of the patients with ChAc. The immunoblot analysis revealed remarkably reduced chorein immunoreactivity in all patients with MLS. The immunoprecipitation analysis indicated a direct or indirect chorein-XK interaction.ConclusionsIn this study, XK pathogenic mutations were identified in all 6 MLS cases, including novel mutations. Chorein immunoreactions were significantly reduced in MLS erythrocyte membranes. In addition, we demonstrated a possible interaction between the chorein and XK protein via molecular analysis. The reduction in chorein expression is similar to that between Kell antigens and XK protein, although the chorein-XK interaction is a possibly noncovalent binding unlike the covalent Kell-XK complex. Our results suggest that reduced chorein levels following lack of XK protein are possibly associated with molecular pathogenesis in MLS.

Postprandial intestinal hyperemia: role of bile salts in the ileum

1981 ◽  
Vol 241 (6) ◽  
pp. G469-G477 ◽  
Author(s):  
P. R. Kvietys ◽  
J. M. McLendon ◽  
D. N. Granger
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Bile Salt ◽  
Bile Salts ◽  
Dependent Manner ◽  
Salt Solutions ◽  
Dose Dependent ◽  
Oxygen Difference ◽  
Artificial Pressure

In an autoperfused dog ileum preparation, artificial pressure, venous outflow pressure, blood flow, and arteriovenous oxygen difference were measured while bile and bile salt solutions, at physiological concentrations, were placed in the lumen. Intraluminal placement of endogenous bile, synthetic bile, or bile salt solutions increased ileal blood flow (99 +/- 10, 94 +/- 20, and 104 +/- 17%, respectively) and oxygen uptake (30 +/- 5, 36 +/- 9, and 28 +/- 5%, respectively). Endogenous bile pretreated with cholestyramine, a bile salt-sequestering resin, did not alter ileal blood flow, yet increased ileal oxygen uptake by 11 +/- 3%, a response similar to that observed while Tyrode's solution (the vehicle) was in the lumen. Intra-arterial infusion of bile salts increased ileal blood flow in a dose-dependent manner, while not significantly altering ileal oxygen uptake. The results of the present study indicate that bile salts play an important role in the functional (postprandial) hyperemia in the ileum by 1) directly dilating the ileal vasculature and 2) enhancing ileal metabolism during their active absorption.

Notizen: Fluorescence and Membrane-Action of Tetracaine

1977 ◽  
Vol 32 (1-2) ◽  
pp. 135-136 ◽  
Author(s):  
J. G. R. Elferink
Keyword(s):  
Erythrocyte Membrane ◽  
Alkyl Chain ◽  
Erythrocyte Membranes ◽  
Membrane Action

Abstract Tetracaine, Fluorescence, Erythrocyte Membrane The fluorescence of tetracaine depends on the micro-environment of the molecule and increases with increasing hydrophobicity. The presence of erythrocyte membranes strongly enhances tetracaine fluorescence. The results support the view that the alkyl chain and aromatic part of tetracaine is embedded in apolar regions of the lipid or protein phase of the membrane.

Protective Effect of Quaternary Piperidinium Salts on Lipid Oxidation in the Erythrocyte Membrane

1999 ◽  
Vol 54 (5-6) ◽  
pp. 424-428 ◽  
Author(s):  
Halina Kleszczyńska ◽  
Małgorzata Oświęcimska ◽  
Janusz Sarapuk ◽  
Stanisław Przestalski ◽  
Stanisław Witek
Keyword(s):  
Lipid Oxidation ◽  
Chain Length ◽  
Erythrocyte Membrane ◽  
Alkyl Chain ◽  
Alkyl Chain Length ◽  
Erythrocyte Membranes ◽  
Negative Consequences ◽  
Rosa Rugosa ◽  
Antioxidant Efficiency ◽  
Comparison Of The Results

Abstract A new series of amphiphilic compounds with incorporated antioxidant functional group has been investigated. Piperidinium bromides, differing in the alkyl chain length (8, 10, 12, 14 and 16 carbon atoms in the chain) were synthesised to protect biological and/or model membranes against peroxidation and following negative consequences. Their antioxidant activity was studied with erythrocytes subjected to UV radiation. The salts used inhibited lipid oxidation in the erythrocyte membrane. The degree of this inhibition depended on the alkyl chain length of the bromide used and increased with increasing alkyl chain length. A comparison of the results obtained for piperidinium bromides with those obtained for the widely used antioxidant 3,5-di-t-butyl-4-hydroxytoluene (BHT) revealed that only two shortest alkyl chain salts were less efficient than BHT in protecting erythrocyte membranes. A similar comparison with antioxidant efficiency of flavonoids extracted from Rosa rugosa showed that they protected the membranes studied more weakly than the least effective eight-carbon alkyl chain piperidinium bromide. The three compounds of longest alkyl chains were the most active antioxidants. Their activities did not differ significantly.

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