scholarly journals A rapid method for the preparation of relatively pure metabolically competent synaptosomes from rat brain

1978 ◽  
Vol 176 (2) ◽  
pp. 365-370 ◽  
Author(s):  
R F G Booth ◽  
J B Clark
Keyword(s):  
Electron Microscopy ◽  
Rat Brain ◽  
Rapid Method ◽  
Sucrose Gradient ◽  
Enzyme Assays ◽  
Marker Enzyme ◽  
Flotation Technique

A rapid (less than 2h) method is described for the preparation of synaptosomes from rat brain by using a discontinuous Ficoll/sucrose gradient by a flotation technique. These synaptosomes are metabolically active and minimally (less than 5%) contaminated with ‘free’ mitochondria as judged by marker-enzyme assays and electron microscopy.

scholarly journals Sialic acid in crude myelin fractions from rat brain

1975 ◽  
Vol 148 (3) ◽  
pp. 375-380 ◽  
Author(s):  
O K Langley
Keyword(s):  
Electron Microscopy ◽  
Sialic Acid ◽  
Rat Brain ◽  
Satellite Cell ◽  
Plasma Membranes ◽  
Enzyme Assays ◽  
Marker Enzyme ◽  
Cellular Membranes ◽  
Cell Plasma ◽  
Ultrastructural Appearance

Protein- and lipid-bound sialic acid was assayed in myelin fractions isolated by four different methods from rat brain homogenates. The extent to which non-myelin cellular membranes contaminate these fractions was assessed by electron microscopy and marker-enzyme assays. Small amounts of sialic acid found in the least contaminated myelin fractions are considered to be constituents of axonal and satellite cell plasma membranes known to be present. The data are discussed with reference to the ultrastructural appearance of myelin.

20 alpha-Hydroxysteroid dehydrogenase and 17 beta-estradiol dehydrogenase localize in cytosol of human term placenta

1982 ◽  
Vol 242 (3) ◽  
pp. E178-E183
Author(s):  
R. C. Strickler ◽  
B. Tobias
Keyword(s):  
Electron Microscopy ◽  
Dehydrogenase Activity ◽  
Hydroxysteroid Dehydrogenase ◽  
Subcellular Fractions ◽  
Enzyme Assays ◽  
Marker Enzyme ◽  
Differential Centrifugation ◽  
Experimental Conditions ◽  
Human Term Placenta ◽  
Term Placenta

The 20 alpha-hydroxysteroid dehydrogenase activity in human term placenta has been localized by different investigators to nuclear, mitochondrial, microsomal, and cytosolic subcellular fractions. Furthermore, in the cytosol, 20 alpha-hydroxysteroid dehydrogenase activity may be a second function of the enzyme that mediates 17 beta-estradiol dehydrogenase activity. To search for a unique 20 alpha-hydroxysteroid dehydrogenase, human placental villous tissue, homogenized in three different buffer systems, was fractionated by differential centrifugation, and the 17 beta- and 20 alpha-activities were measured by radioisotope conversion assay. The enrichment and purity of the subcellular fractions were shown by marker enzyme assays and electron microscopy studies. Under all experimental conditions, 20 alpha-hydroxysteroid dehydrogenase activity was identified only in the 105,000 g placental cytosol: intact, osmotically ruptured, and acetone-extracted mitochondria, nuclei, and microsomes did not convert progesterone to 20 alpha-dihydroprogesterone. Furthermore, because 17 beta-estradiol dehydrogenase activity was in large part soluble in the cytosol, these localization studies are consistent with the hypothesis that the 20 alpha- and 17 beta-oxidoreductase activities in human placenta reside on one soluble protein.

scholarly journals A sensitive method for measuring polymerized and depolymerized forms of tubulin in tissues.

1977 ◽  
Vol 74 (2) ◽  
pp. 341-350 ◽  
Author(s):  
D G Pipeleers ◽  
M A Pipeleers-Marichal ◽  
P Sherline ◽  
D M Kipnis
Keyword(s):  
Electron Microscopy ◽  
Rat Brain ◽  
Rapid Method ◽  
Binding Assay ◽  
Fed State ◽  
Stabilizing Solution ◽  
Rat Liver Cells ◽  
Wet Weight ◽  
Brain Tubulin ◽  
Sensitive Method

A rapid method for measuring polymerized and depolymerized forms of tubulin in tissues has been developed. The procedure consists of homogenization and centrifugation of the tissue in a microtubule-stabilizing solution and depolymerization of the precipitated microtubules; polymerized and depolymerized forms of tubulin are quantitated by a colchicine-binding assay. The validity of the technique was assessed by electron microscopy and recovery studies with labeled and unlabeled preparations of polymerized and depolymerized forms of rat brain tubulin. The sensitivity of this technique allows quantitation of tubulin in 150 micrograms of tissue, wet weight. The method demonstrated that both the polymerized and depolymerized forms of tubulin were present in rat liver cells, and that in the fed state 31.3 +/-0.7% of the total tubulin pool was in the polymerized form.

scholarly journals A simple and rapid method for the preparation of adenosine triphosphatase from submitochondrial particles

1975 ◽  
Vol 148 (3) ◽  
pp. 533-537 ◽  
Author(s):  
R B Beechey ◽  
S A Hubbard ◽  
P E Linnett ◽  
A D Mitchell ◽  
E A Munn
Keyword(s):  
Electron Microscopy ◽  
Rapid Method ◽  
Adenosine Triphosphatase ◽  
Pure Form ◽  
Heart Mitochondria ◽  
Polyacrylamide Gels ◽  
Submitochondrial Particles ◽  
Bovine Heart

An almost pure form of the bovine heart mitochondrial adenosine triphosphatase (ATPase) is released from the membrane by shaking submitochondrial particles with chloroform. Analyses on polyacrylamide gels and by electron microscopy, and also sensitivity to inhibitors, show that the chloroform-released enzyme is similar to other ATPase preparations from bovine heart mitochondria.

Formation of chlamydospores in Gilbertella persicaria

1981 ◽  
Vol 59 (5) ◽  
pp. 908-928 ◽  
Author(s):  
Martha J. Powell ◽  
Charles E. Bracker ◽  
David J. Sternshein
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Light And Electron Microscopy ◽  
Multivesicular Bodies ◽  
Marker Enzyme ◽  
Transparent Layer ◽  
Thiamine Pyrophosphatase ◽  
Gilbertella Persicaria

The cytological events involved in the transformation of vegetative hyphae of the zygomycete Gilbertella persicaria (Eddy) Hesseltine into chlamydospores were studied with light and electron microscopy. Thirty hours after sporangiospores were inoculated into YPG broth, swellings appeared along the aseptate hyphae. Later, septa, traversed by plasmodesmata, delimited each end of the hyphal swellings and compartmentalized these hyphal regions as they differentiated into chlamydospores. Nonswollen regions adjacent to chlamydospores remained as isthmuses. Two additional wall layers appeared within the vegetative wall of the developing chlamydospores. An alveolate, electron-dense wall formed first, and then an electron-transparent layer containing concentrically oriented fibers formed between this layer and the plasma membrane. Rather than a mere condensation of cytoplasm, development and maturation of the multinucleate chlamydospores involved extensive cytoplasmic changes such as an increase in reserve products, lipid and glycogen, an increase and then disappearance of vacuoles, and the breakdown of many mitochondria. Underlying the plasma membrane during chlamydospore wall formation were endoplasmic reticulum, multivesicular bodies, vesicles with fibrillar contents, vesicles with electron-transparent contents, and cisternal rings containing the Golgi apparatus marker enzyme, thiamine pyrophosphatase. Acid phosphatase activity was localized cytochemically in a cisterna which enclosed mitochondria and in vacuoles which contained membrane fragments. Tightly packed membrane whorls and single membrane bounded sacs with finely granular matrices surrounding vacuoles were unique during chlamydospore development. Microbodies were rare in the mature chlamydospore, but endoplasmic reticulum was closely associated with lipid globules. As chlamydospores developed, the cytoplasm in the isthmus became highly vacuolated, lipid globules were closely associated with vacuoles, mitochondria were broken down in vacuoles, unusual membrane configurations appeared, and eventually the membranes degenerated. Unlike chlamydospores, walls of the isthmus did not thicken, but irregularly shaped appositions containing numerous channels formed at intervals on the inside of these walls. The pattern of cytoplasmic transformations during chlamydospore development is similar to events leading to the formation of zygospores and sporangiospores.

A rapid method for the regional dissection of the rat brain

1980 ◽  
Vol 13 (3) ◽  
pp. 453-456 ◽  
Author(s):  
Thomas G. Heffner ◽  
John A. Hartman ◽  
Lewis S. Seiden
Keyword(s):  
Rat Brain ◽  
Rapid Method
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