Erythrocyte contamination of leukocyte populations following density-gradient centrifugation results in artificially high levels of human leukocyte HMG-CoA reductase activity

Production of butyrate by the holotrich protozoon Dasytricha ruminantium involves the enzymes of glycolysis, pyruvate:ferredoxin oxidoreductase, acetyl-CoA:acetyl-CoA C-acetyltransferase, 3-hydroxybutyryl-CoA dehydrogenase, 3-hydroxyacyl-CoA hydro-lyase, 3-hydroxyacyl-CoA reductase, phosphate butyryltransferase and butyrate kinase. Subcellular fractionation by differential and density-gradient centrifugation on sucrose gradients indicated that all those enzymes except pyruvate:ferredoxin oxidoreductase were non-sedimentable at 6 × 10(6) g-min. Butyrate kinase and phosphate butyryltransferase were associated with the large- and small-granule fractions. Thus, although metabolic reactions necessary for butyrate production proceed predominantly in the cytosol, hydrogenosomes play a key role in the conversion of pyruvate into acetyl-CoA.

Download Full-text

Measurement of human leukocyte microsomal HMG-CoA reductase activity.

The Journal of Lipid Research ◽

10.1016/s0022-2275(20)37733-6 ◽

1984 ◽

Vol 25 (9) ◽

pp. 967-978 ◽

Cited By ~ 5

Author(s):

H J Harwood ◽

M Schneider ◽

P W Stacpoole

Keyword(s):

Reductase Activity ◽

Human Leukocyte ◽

Hmg Coa Reductase ◽

Coa Reductase

Download Full-text

Uranyl Acetate and Rotary Shadowing to Increase the Contrast of Small Aggregated Virus Particles

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100064037 ◽

1969 ◽

Vol 27 ◽

pp. 424-425

Author(s):

Lee F. Ellis ◽

Richard M. Van Frank ◽

Walter J. Kleinschmidt

Keyword(s):

Electron Microscopy ◽

Tissue Culture ◽

Density Gradient ◽

Density Gradient Centrifugation ◽

Gradient Centrifugation ◽

Uranyl Acetate ◽

Interferon Inducer ◽

Virus Particles ◽

Staining Methods ◽

Rotary Shadowing

The extract from Penicillum stoliniferum, known as statolon, has been purified by density gradient centrifugation. These centrifuge fractions contained virus particles that are an interferon inducer in mice or in tissue culture. Highly purified preparations of these particles are difficult to enumerate by electron microscopy because of aggregation. Therefore a study of staining methods was undertaken.

Download Full-text

The Combining Ability of Glycoproteins IIb, IIIa and Ca2+ in EDTA-Treated Nonaggregable Platelets

Thrombosis and Haemostasis ◽

10.1055/s-0038-1665326 ◽

1983 ◽

Vol 50 (04) ◽

pp. 848-851 ◽

Cited By ~ 11

Author(s):

Marjorie B Zucker ◽

David Varon ◽

Nicholas C Masiello ◽

Simon Karpatkin

Keyword(s):

Density Gradient ◽

Combining Ability ◽

Density Gradient Centrifugation ◽

Gradient Centrifugation ◽

Electrophoretic Pattern ◽

Sucrose Density Gradient ◽

Irreversible Loss ◽

Sucrose Density Gradient Centrifugation ◽

Crossed Immunoelectrophoresis ◽

Triton X

SummaryPlatelets deprived of calcium and incubated at 37° C for 10 min lose their ability to bind fibrinogen or aggregate with ADP when adequate concentrations of calcium are restored. Since the calcium complex of glycoproteins (GP) IIb and IIIa is the presumed receptor for fibrinogen, it seemed appropriate to examine the behavior of these glycoproteins in incubated non-aggregable platelets. No differences were noted in the electrophoretic pattern of nonaggregable EDTA-treated and aggregable control CaEDTA-treated platelets when SDS gels of Triton X- 114 fractions were stained with silver. GP IIb and IIIa were extracted from either nonaggregable EDTA-treated platelets or aggregable control platelets with calcium-Tris-Triton buffer and subjected to sucrose density gradient centrifugation or crossed immunoelectrophoresis. With both types of platelets, these glycoproteins formed a complex in the presence of calcium. If the glycoproteins were extracted with EDTA-Tris-Triton buffer, or if Triton-solubilized platelet membranes were incubated with EGTA at 37° C for 30 min, GP IIb and IIIa were unable to form a complex in the presence of calcium. We conclude that inability of extracted GP IIb and IIIa to combine in the presence of calcium is not responsible for the irreversible loss of aggregability that occurs when whole platelets are incubated with EDTA at 37° C.

Download Full-text