Information Regarding both Molecular‐Weight Distribution and Density Distribution in a Polymer Subjected to Density‐Gradient Centrifugation

1963 ◽  
Vol 38 (3) ◽  
pp. 597-600 ◽  
Author(s):  
J. J. Hermans
Keyword(s):  
Molecular Weight ◽  
Density Distribution ◽  
Density Gradient ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation

scholarly journals Evidence that platelet density depends on the alpha-granule content in platelets

Blood ◽  
1984 ◽  
Vol 63 (2) ◽  
pp. 482-485 ◽  
Author(s):  
BA van Oost ◽  
AP Timmermans ◽  
JJ Sixma
Keyword(s):  
Density Distribution ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Platelet Rich Plasma ◽  
Gradient Centrifugation ◽  
Buoyant Density ◽  
Adenosine Diphosphate ◽  
Density Gradients

Abstract The relation between platelet buoyant density and beta-thromboglobulin (beta-TG), a marker for platelet alpha-granule content, was assessed by three independent approaches. (1) Platelets were separated on iso- osmolar discontinuous Stractan density gradients into five fractions, ranging in density from 1.061 g/ml to 1.091 g/ml (20 degrees C). The beta-TG content (mean +/- SD, n = 17) increased with the platelet density from 27.8 +/- 8.6 micrograms beta-TG/10(9) cells (20% less- dense platelets) up to 65.6 +/- 15.5 micrograms beta-TG/10(9) cells (15% most-dense platelets). (2) Activation of platelets in platelet- rich plasma with thrombin, adenosine diphosphate, collagen, or epinephrine resulted in a decreased density of the platelets. This was only seen when there was simultaneous secretion of beta-TG. (3) The less-dense and the more-dense platelet fractions, after isolation by density gradient centrifugation, were separately treated with thrombin. After complete degranulation, the density distribution of the originally less-dense and more-dense platelets were identical and were much narrower than the density distribution of resting platelets.

scholarly journals Evidence that platelet density depends on the alpha-granule content in platelets

Blood ◽  
1984 ◽  
Vol 63 (2) ◽  
pp. 482-485
Author(s):  
BA van Oost ◽  
AP Timmermans ◽  
JJ Sixma
Keyword(s):  
Density Distribution ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Platelet Rich Plasma ◽  
Gradient Centrifugation ◽  
Buoyant Density ◽  
Adenosine Diphosphate ◽  
Density Gradients

The relation between platelet buoyant density and beta-thromboglobulin (beta-TG), a marker for platelet alpha-granule content, was assessed by three independent approaches. (1) Platelets were separated on iso- osmolar discontinuous Stractan density gradients into five fractions, ranging in density from 1.061 g/ml to 1.091 g/ml (20 degrees C). The beta-TG content (mean +/- SD, n = 17) increased with the platelet density from 27.8 +/- 8.6 micrograms beta-TG/10(9) cells (20% less- dense platelets) up to 65.6 +/- 15.5 micrograms beta-TG/10(9) cells (15% most-dense platelets). (2) Activation of platelets in platelet- rich plasma with thrombin, adenosine diphosphate, collagen, or epinephrine resulted in a decreased density of the platelets. This was only seen when there was simultaneous secretion of beta-TG. (3) The less-dense and the more-dense platelet fractions, after isolation by density gradient centrifugation, were separately treated with thrombin. After complete degranulation, the density distribution of the originally less-dense and more-dense platelets were identical and were much narrower than the density distribution of resting platelets.

scholarly journals Purification and characterization of kynurenine-2-oxoglutarate aminotransferase from the liver, brain and small intestine of rats

1975 ◽  
Vol 151 (2) ◽  
pp. 399-406 ◽  
Author(s):  
T Noguchi ◽  
Y Minatogawa ◽  
E Okuno ◽  
M Nakatani ◽  
M Morimoto ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Weight ◽  
Small Intestine ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Sucrose Density Gradient ◽  
Sucrose Density Gradient Centrifugation ◽  
Ph Optimum ◽  
Wide Range

1. Kynurenine-2-oxoglutarate aminotransferase (isoenzyme 1) was purified to homogeneity from the liver, brain and small intestine of rats by the same procedure. The three enzyme preparations had nearly identical pH optima, substrate specificities and molecular weights. Isoenzyme 1 was active with 2-oxoglutarate but not with pyruvate as amino acceptor, and utilized a wide range of amino acids as amino donors. Amino acids were effective in the following order to activity: L-aspartate greater than L-tyrosine greater than L-phenylalanine greater than L-tryptophan greater than 5-hydroxy-L-tryptophan greater than L-kynurenine. The molecular weight was approximately 88 000 as determined by sucrose-density-gradient centrifugation. The pH optimum was between 8.0 and 8.5. On the basis of substrate specificity, substrate inhibition, subcellular distribution and polyacrylamide-disc-gel electrophoresis, it is suggested that liver, brain and small intestinal kynurenine-2-oxoglutarate aminotransferase (isoenzyme 1) is identical with mitochondrial tyrosine-2-oxoglutarate aminotransferase and also with mitochondrial aspartate-2-oxoglutarate aminotransferase. 2. An additional kynurenine-2-oxoglutarate aminotransferase (isoenzyme 2) was purified from the liver. This enzyme was specific for 2-oxoglutarate and L-kynurenine. Sucrose-density-gradient centrifugation gave a molecular weight of approximately 100 000. The pH optimum was between 6.0 and 6.5. This enzyme was not detected in the brain or small intestine.

Characterization of proteins associated with nuclear ribonucleoprotein particles by two-dimensional polyacrylamide gel electrophoresis

1979 ◽  
Vol 57 (1) ◽  
pp. 32-42 ◽  
Author(s):  
D. Suria ◽  
C. C. Liew
Keyword(s):  
Molecular Weight ◽  
Density Gradient ◽  
Density Gradient Centrifugation ◽  
Gradient Centrifugation ◽  
Two Dimensional ◽  
Molecular Weights ◽  
Electrophoretic Patterns ◽  
Phenol Extraction ◽  
Chromatin Proteins ◽  
Nuclear Ribonucleoprotein

Rat liver nuclear ribonucleoprotein particles were prepared by two different methods and defined as 40S ribonucleoprotein (40S RNP) and heterogeneous nuclear ribonucleoprotein (HnRNP) particles. The RNP particles were either solubilized in 8 M urea – 6 mM 2-mercaptoethanol – 20 mM glycine – 20 mM Tris–HCl (pH 8.4) or subjected to removal of RNA by phenol extraction prior to solubilizing the proteins in the urea buffer. The proteins associated with 40S RNP and HnRNP were heterogeneous and very similar in their electrophoretic patterns when analyzed by two-dimensional PAGE, except a protein with molecular weight of 62 000 and an isoelectric point (pI) of 6.2 was present only in HnRNP particles. At least 12 major and 22 minor components could be identified in both preparations. The major proteins were found at pI values varying from 6.0 to 8.5 and with molecular weights from 32 000 to 42 000, and a group of proteins with molecular weight approximately 65 000 were more prominent in HnRNP than in 40S RNP. The other components were found mainly at pI ranges from 5.0 to 6.5 with molecular weights from 43 000 to 65 000. The phenol method extracted essentially all proteins associated with either 40S RNP and HnRNP, but was less effective in extracting a group of proteins with pI values from 5.0 to 5.5 and more efficient for proteins with pI values from 7.5 to 8.5. When chromatin proteins isolated by phenol extraction were compared with HnRNP particle proteins isolated by the same method, the electrophoretic mobilities of the HnRNP particle proteins were found to be identical with a fraction of nonhistone chromatin proteins. The 40S RNP particles were further purified by metrizamide isopycnic density gradient centrifugation. The electrophoretic patterns of these proteins were very similar to those prepared by sucrose density gradient centrifugation. Therefore, we concluded that the proteins of RNP particles constituted part of the chromatin proteins.

scholarly journals Studies on the polydispersity and heterogeneity of cartilage proteoglycans. Identification of 3 proteoglycan structures in bovine nasal cartilage

1975 ◽  
Vol 151 (3) ◽  
pp. 581-594 ◽  
Author(s):  
J J Hopwood ◽  
H C Robinson
Keyword(s):  
Molecular Weight ◽  
Density Gradient ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Chondroitin Sulphate ◽  
Relative Proportion ◽  
Average Molecular Weight ◽  
Nasal Cartilage ◽  
Cscl Density Gradient ◽  
Gradient Fractionation

1. Three chondroitin sulphate components were isolated from adult bovine nasal cartilage after treatment with alkaline NaB3H4. Average molecular weights of 13000, 18 600 and 28 000 were obtained for chondroitin sulphate species representing 10, 52 and 38% (w/w) of the total chondroitin sulphate respectively. Each chondroitin sulphate pool has a narrow molecular-weight distribution. 2. A proteoglycan subunit preparation, isolated from one nasal cartilage by extraction and density-gradient fractionation in dissociative solvents, partitioned on a CsCl density gradient according to size and composition. Variation of proteoglycan molecular weight across the gradient was directly related to the average chondrotin sulphate chain length, which in turn reflected the relative proportion of the three chondroitin sulphate pools in each proteoglycan fraction. Consideration of proteoglycan molecular parameters, compositions and behaviour on sedimentation leads to a proposal that nasal cartilage contains 3 distinct proteoglycan pools, each of which has a constant number of chondroitin sulphate side chains of different average molecular weight. 3. Molecular-weight distribution parameters for these proteoglycan preparations indicate that all serine residues on the protein core capable of initiating chondroitin sulphate biosynthesis are occupied and that proteoglycan polydispersity results directly from the polydispersity of the attached chondroitin sulphate component.

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

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.

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

1983 ◽  
Vol 50 (04) ◽  
pp. 848-851 ◽  
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.

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