scholarly journals A species-non-specific liver plasma-membrane antigen and its involvement in chronic active hepatitis

1980 ◽  
Vol 186 (3) ◽  
pp. 679-685 ◽  
Author(s):  
T A De Kretser ◽  
I G McFarlane ◽  
A L Eddleston ◽  
R Williams

Rabbit liver plasma membranes were isolated and purified by using an aqueous two-phase polymer system. Examination of these preparations with respect to electron-microscopical appearance, distribution of marker enzymes and gross biochemical composition revealed them to be free from contamination by intracellular components. Sera from ten patients with chronic active hepatitis, four with and six without hepatitis B viral markers (HBsAg) in their sera, produced a single precipitin line on immunodiffusion against a detergent extract of the isolated plasma membranes. Sera from HBsAg-positive and HBsAg-negative patients reacted against the same antigen. This antigen was enriched in the plasma membrane preparations compared with whole-liver homogenates and was identical with a species-non-specific antigen in a macromolecular fraction of normal human liver, which has been previously described as liver-specific lipoprotein.

1990 ◽  
Vol 68 (1) ◽  
pp. 138-144
Author(s):  
J.-M. Touze-Soulet ◽  
J. D. Weete ◽  
M. Sancholle ◽  
J. Rami ◽  
R. Dargent

Subfractions of microsomal membranes from the biotin heteroauxotroph Hypomyces chlorinus Tul., cultured in media containing optimal or suboptimal levels of the vitamin, were isolated using a two-phase polymer system and characterized as plasma membrane-enriched on the basis of absence of Zn2+-induced aggregation, enrichment of appropriate enzyme markers, and phosphotungstic acid – chromic acid staining. The protein/lipid ratio of membranes from the biotin-sufficient and -deficient cultures was 2; the phospholipid content was 126 and 181 μg/mg protein; and the sterol/phospholipid molar ratios were 0.38 and 0.16, respectively, with ergosterol as the predominant sterol. The lipids were qualitatively similar in the plasma membrane fractions from the two treatments. Ergosterol content of the membrane fractions from mycelium cultured in low biotin medium was 40–100% less than that from the corresponding biotin-sufficient cultures. A nonphosphorus glycolipid was the predominant lipid of the plasma membranes from both treatments.Key words: Hypomyces, plasma membrane, sterols, biotin deficiency, ergosterol.


1975 ◽  
Vol 53 (8) ◽  
pp. 914-920 ◽  
Author(s):  
R. L. Juliano ◽  
E. Gagalang

Plasma membranes were prepared from cultured Chinese hamster ovary cells utilizing a two-phase polymer system and were characterized by enzymatic and chemical assay, and by electron microscopy. The usual degree of purification of presumptive membrane markers such as Na+–K+ ATPase (ATP phosphohydrolase, EC 3.6.1.3) ranged from three-to eightfold. Gel electrophoresis in SDS revealed several polypeptides and two glycopeptides which were enriched in the plasma membrane fraction.


2014 ◽  
Vol 63 (3-4) ◽  
pp. 309-314 ◽  
Author(s):  
Grażyna Kłobus ◽  
Jolanta Marciniak ◽  
Józef Buczek

The biochemical comparison between two forms of nitrate reductase from cucumber roots: the soluble enzyme and the plasma membrane-associated one was made. Soluble nitrate reductase was purified on the blue-Sepharose 4B. The nitrate reductase bound with plasma membranes was isolated from cucumber roots by partition of microsomes in the 6.5% dextran-PEG two phase system. The molecular weight of native enzyme estimated with HPLC was 240 kDa and 114 kDa for the soluble and membrane bounded enzyme, respectively. Temperature induced phase separation in Triton X-114 indicated a huge difference in hydrophobicity of the plasma membrane associated nitrate reductase and soluble form of enzyme. Small differences were observed in partial activities of plasma membrane nitrate reductase and soluble nitrate reductase. Also experiments with polyclonal antiserum raised against the native nitrate reductase showed some differences in the immunological properties of both forms of the nitrate reductase. The above results indicated that in cucumber roots two different forms of the nitrate reductase are present.


1990 ◽  
Vol 115 (2) ◽  
pp. 274-277 ◽  
Author(s):  
Gene Lester

Using an aqueous polymer two-phase [polyethylene glycol (PEG) 3400/dextran T500, 6.2%: 6.2%, w/w] partitioning procedure combined with isopycnic fractionation, plasma membranes derived from muskmelon (Cucumis melo L. var. reticulates Naud.) leaf blades have been isolated and examined for marker enzyme activity, density, and molecular composition. After aqueous polymer partitioning, plasma membranes were centrifuged on a linear sucrose density gradient, and a single band was found at the 31% (w/w) sucrose (1.13 g-cm-3). Identification of plasma membranes was performed by the combination of K+-stimulated ATPase, pH 6.5, vanadate inhibition of ATPase and KNO3-insensitive ATPase activity. Plasma membranes from seedling leaves grown for 5 days at 15C had the highest concentration of total phospholipids, the lowest concentration of proteins, and a total sterol concentration not significantly different from leaves grown at 30C. The total sterol to total phospholipid ratio of the plasma membrane from leaves grown for 5 days at 15C was ≈1:1; from leaves grown for 10 days at 15C or 5 days at 30C the ratio was ≈2:1; and from leaves grown for 10 days at 30C the ratio was ≈3:1. The plasma membrane phospholipid saturated to unsaturated fatty acid ratio from leaves grown for 5 days at 15C was ≈0.8:1.0; from leaves grown for 10 days at 15C or 5 days at 30C the ratio was ≈1.0:1.0; and from leaves grown for 10 days at 30C it was 1.4:1.0.


1984 ◽  
Vol 62 (9) ◽  
pp. 831-836 ◽  
Author(s):  
Dominick Pallotta ◽  
Anne Barden ◽  
Rémi Martel ◽  
Josée Kirouac-Brunet ◽  
François Bernier ◽  
...  

Two methods are described for preparing plasma membranes from Physarum polycephalum plasmodia. In the first method Plasmodia were broken in homogenizing medium (250 mM sucrose, 1 mM ZnCl2, 10 mM Tris (pH 8.0)), and the nuclei were removed by low speed centrifugation. A crude membrane fraction was collected and the membranes were purified by centrifugation in a linear 30–65% (w/w) sucrose gradient. The membranes sedimented in a single band at a density of 1.26 g/cm3. In the second method the plasmodia were broken in the same homogenizing medium and a crude membrane fraction was prepared by differential centrifugation. The membranes were purified by the Dextran – polyethylene glycol aqueous two-phase system. Membranes from both preparations were found by enzymatic assay and by electron microscopy to be virtually free of contaminating cell organelles. Analyses by one- and two-dimensional polyacrylamide gel electrophoresis showed a great similarity in the proteins from two-phase and sucrose gradient prepared membranes, indicating that either technique can be used to prepare membranes for protein studies. An analysis by two-dimensional gel electrophoresis of plasma membrane proteins from amoebae and plasmodia showed differences in some of the major proteins, indicating that changes occur in plasma membrane proteins during differentiation.


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