Isolation Of A Golgi Apparatus-Rich Fraction From Rat Liver: I. Method and Morphology
TL;DR: Examination of sections of purified fractions by electron microscopy showed fields of morphologically intact units of Golgi apparatus consisting of stacks of parallel flattened cisternae, secretory vesicles, and small vesicular profiles.
Abstract: Golgi apparatus were released without fixatives from rat hepatocytes by gentle homogenization, concentrated by differential centrifugation, and purified by sucrose gradient centrifugation. Examination of sections of purified fractions by electron microscopy showed fields of morphologically intact units of Golgi apparatus consisting of stacks of parallel flattened cisternae, secretory vesicles, and small vesicular profiles. Negative staining of unfixed pellets revealed a complex network of anastomotic tubules continuous with platelike structures and secretory vesicles. These structures corresponded, respectively, to the small vesicular profiles and parallel flattened cisternae with attached secretory vesicles of sectioned material. Small fragments of granular endoplasmic reticulum were often closely associated with the peripheral tubules, suggesting sites of continuity in intact hepatocytes.
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TL;DR: The title of the Nobel Lecture of George Palade (1 August, p. 347) should have been "Intracellular aspects of the process of protein secretion."
Abstract: The title of the Nobel Lecture of George Palade (1 August, p. 347) should have been "Intracellular aspects of the process of protein secretion."
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TL;DR: Rat liver microsomal fractions have been equilibrated in various types of linear density gradients and four groups of constituents have been classified, in the order of increasing median density, into four groups labeled a, b, c, and d.
Abstract: Rat liver microsomal fractions have been equilibrated in various types of linear density gradients. 15 fractions were collected and assayed for 27 constituents. As a result of this analysis microsomal constituents have been classified, in the order of increasing median density, into four groups labeled a, b, c, and d. Group a includes: monoamine oxidase, galactosyltransferase, 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase, and cholesterol; group b: NADH cytochrome c reductase, NADPH cytochrome c reductase, aminopyrine demethylase, cytochrome b(5), and cytochrome P 450; group c: glucose 6-phosphatase, nucleoside diphosphatase, esterase, beta-glucuronidase, and glucuronyltransferase; group d: RNA, membrane-bound ribosomes, and some enzymes probably adsorbed on ribosomes: fumarase, aldolase, and glutamine synthetase. Analysis of the microsomal fraction by differential centrifugation in density gradient has further dissociated group a into constituents which sediment more slowly (monoamine oxidase and galactosyltransferase) than those of groups b and c, and 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase, and the bulk of cholesterol which sediment more rapidly (group a2). The microsomal monoamine oxidase is attributed, at least partially, to detached fragments of external mitochondrial membrane. Galactosyltransferase belongs to the Golgi complex. Group a2 constituents are related to plasma membranes. Constituents of groups b and c and RNA belong to microsomal vesicles derived from the endoplasmic reticulum. These latter exhibit a noticeable biochemical heterogeneity and represent at the most 80% of microsomal protein, the rest being accounted for by particles bearing the constituents of groups a and some contaminating mitochondria, lysosomes, and peroxisomes. Attention is called to the operational meaning of microsomal subfractions and to their cytological complexity.
366 citations
TL;DR: Cerium appears to be a better capture agent for inorganic phosphate than lead in that reaction product is usually more uniform and more consistently reproducible when cerium is used.
Abstract: Cerium ions have been used as the capture agent for inorganic phosphate released during the enzymatic hydrolysis of phosphate-containing substrates by a variety of phosphatases. Cerium phosphate reaction product accumulation is proportional to the amount of enzyme present in a cell-free model system. Ultrastructurally, cerium phosphate reaction product appears as a very fine electron-dense precipitate. Cerium appears to be a better capture agent for inorganic phosphate than lead in that reaction product is usually more uniform and more consistently reproducible when cerium is used. Furthermore, nonspecific deposits of reaction product that are commonly encountered in lead-based phosphatase reactions are virtually nonexistent when cerium is the capture agent.
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TL;DR: The results obtained allowed us to assess the importance of knowing the carrier and removal status of canine coronavirus, as a source of infection for other animals, not necessarily belonging to the same breeds.
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Journal Article•
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TL;DR: The Golgi apparatus or some functional equivalent has been established as a general feature of the eucaryotic plant cell and can be isolated and subjected to physiological and biochemical study.
Abstract: Secretion (90, 139, 140), used in the context of this review, refers to the process by which substances produced in the cytoplasm are segregated and transferred to the cell's exterior. Studies of secretion have provided an inte grated view of structure and function where the metabolic systems are local ized in several cell components (39, 57, 80,90, 117, 132, 138, 140, 147, 173, 181, 188,208) . These components include sites of synthesis (ER), sites of con centration and modification (Golgi apparatus), and vehicles for transport to the extracytoplasmic environment (secretion vesicles). Discussions of the early controversy regarding plant Golgi apparatus can be found in the review by Nahm (127) and the articles by Whaley, Kephart & Mollenhauer (207) , and Hrsel (83). In the past decade, however, the Golgi apparatus or some functional equivalent (73) has been established as a general feature of the eucaryotic plant cell (29, 76, 8 1 , 111 , 165, 200, 207). This participant in the integrated processes of cellular secretion can be isolated and subjected to physiological and biochemical study.
257 citations
"Isolation Of A Golgi Apparatus-Rich..." refers methods in this paper
...Detailed studies on the chemistry and enzymology of Golgi apparatus have been hindered by lack of reproducible isolation and purification procedures that permit development of viable cell-free systems (12).Progress was reported with epididymis (7, 22) and later with plants ( 12 , 17, 18), liver (4, 14), and kidney(14),but these preparations have not been subjected to extensive biochemical characterization . Our procedure for rat liver is ......
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...Detailed studies on the chemistry and enzymology of Golgi apparatus have been hindered by lack of reproducible isolation and purification procedures that permit development of viable cell-free systems ( 12 ).Progress was reported with epididymis (7, 22) and later with plants (12, 17, 18), liver (4, 14), and kidney(14),but these preparations have not been subjected to extensive biochemical characterization . Our procedure for rat liver is ......
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TL;DR: The isolated perfused rat liver was used to study the 300-800 A electron-opaque bodies and it was concluded that they are, in all likelihood, very low density lipoproteins and that their formation is blocked by puromycin, presumably through interference with the synthesis of their apoprotein.
215 citations
TL;DR: A Golgi apparatus-rich fraction isolated from rat liver catalyzed the transfer of galactose from UDP-galactose to N-acetylglucosamine with the formation of N-acetylaminolactose as well as the transfer
187 citations
Journal Article•
155 citations