Ultrastructural organization of cytoplasmic nucleoprotein in the exocrine pancreas cells

Hanzon, V.; Hermodsson, Lars; Toschi, G.

doi:10.1016/s0022-5320(59)90016-4

Cited by 50 publications

(8 citation statements)

References 16 publications

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“…The ribosomes that remain attached to the membrane complex under these conditions are not degraded, perhaps because they are present in the more diffuse state suggested by Hanzon, Hermodsson & Toschi (1959) to be the true physiological form of the ribosome. However, the electron micrographs of sections of both the whole cell and membrane complex show large numbers of particles 100-150A in diameter, and they can be obtained in the usual dense form after lysis.…”

Section: Discussionmentioning

confidence: 89%

Cellular components of Bacillus megaterium and their role in protein biosynthesis

Godson¹,

Hunter²,

Butler³

1961

Biochemical Journal

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0*5M-phosphate-salts medium, diluted with 1*5 vol. of water and vigorously shaken by hand until no whole protoplasts could be seen under the microscope. When the weight of protoplasts was smaller (0.2-0-5 g.), the pellet yeast was kindly provided by Brain's Brewery, Cardiff. Salmon (Saimo salar) liver was obtained from the fishmarket. Frogs (Rana temporaria) were kindly supplied by the Department ofZoology. Taka-diastase (lactose-free) was a gift from Parke, Davis and Co. Ltd., and acetone-dried cells of Alcaligenes metalcaligenes (see Dodgson, Melville, Spencer & Williams, 1954) were prepared at the M.R.C. Antibiotic Research Station, Clevedon.

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Section: Discussionmentioning

confidence: 89%

Cellular components of Bacillus megaterium and their role in protein biosynthesis

Godson¹,

Hunter²,

Butler³

1961

Biochemical Journal

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“…The almost complete absence of the 150 A particles in thin sections of unstained material is assumed to be due to lack of contrast, for the thickness of the line seen in such sections is sufficient to accommodate both the particles and the protein layer to which they are attached. The existence of the characteristic 150 A particles within the cytoplasm of the living cell has recently been questioned on the basis of results obtained with freeze-drying (13,30). Hanzon et al (13) state that the RNP particles are artifacts arising from fixation or homogenization.…”

Section: Discussionmentioning

confidence: 99%

“…The existence of the characteristic 150 A particles within the cytoplasm of the living cell has recently been questioned on the basis of results obtained with freeze-drying (13,30). Hanzon et al (13) state that the RNP particles are artifacts arising from fixation or homogenization. Since the time that Palade demonstrated them with the electron microscope (17) and he and Siekevitz showed them to be morphologically similar to the particles attached to the microsomal fraction of liver (18) and pancreas (19), there has been mtmh effort devoted to characterizing the particles biochemically and physically.…”

Section: Discussionmentioning

confidence: 99%

“…Although it is equally satisfactory, the technic of freeze-substitution (28) has been used less frequently. There have been attempts to freeze-dry tissue for electron microscopy (10,23,29) and good results have been obtained recently (13,30). Since the freeze-substitution method of Fern~ndez-Morfin (6,8) has also been successfully applied to the preparation of tissues for electron microscopy, it was used on mouse pancreas in the present study.…”

Section: Introductionmentioning

confidence: 99%

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The Staining of Thin Sections of Mouse Pancreas Prepared by the Fernández-Morán Helium Ii Freeze-Substitution Method

Bullivant

1960

The Journal of Cell Biology

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Small pieces of mouse pancreas were rapidly frozen in helium II, substituted in methanol at --75 ° C., and embedded in methacrylate by ultraviolet polymerization in the cold. The unstained cells show a structure similar to that after OsO4 fixation, except that the RNP particles have little or no contrast and the mitochondria and Golgi zones appear as grey areas without internal structure. After staining the sections by floating them on solutions of lead acetate or osmium tetroxide, there is an increase in contrast of RNP particles, ergastoplasmic membranes, and zymogen granules. Mitochondrial and Golgi membranes, zymogen granule membranes, and a membrane along the outside of the ergastoplasmic cisterna appear in negative contrast. The structure of the ergastoplasm, the existence of RNP particles, and the production of negative contrast are discussed. A modification of Gomori's method for acid phosphatase produces a lead deposit around the periphery of the zymogen granules. Possibly this deposit does not represent the true site of the enzyme, but the results show the feasibility of histochemistry at the level of resolution of the electron microscope.

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“…While techniques and instruments are not available to do this at present, a suitable method of rapid freezing has been developed (Van Harreveld and Crowell, 1964), and very promising results have been obtained by impregnating tissue with gelatin solutions and then sectioning it at low temperature (Bernhard and Nancy, 1964). Freezing as a fixation method has been extensively explored in a number of ways (Gersh, 1956;SjOstrand and Baker, 1958;Hanzon et al, 1959;SjOstrand and Elfvin, 1964;Fern~ndez-Mor~n, 1957, 1960Bullivant, 1960Bullivant, , 1965Rebhun, 1961Rebhun, , 1965Van Harreveld and Crowell, 1964;Van Harreveld et al, 1965). With all these methods the removal of water was followed by embedding in a plastic; although the preservation obtained was good, it had no better claim to reality than that of chemically fixed tissue.…”

Section: Introductionmentioning

confidence: 99%

A Simple Freeze-Fracture Replication Method for Electron Microscopy

Bullivant

Ames

1966

The Journal of Cell Biology

152

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A simple method to achieve results similar to the freeze-etching technique of Moor et al. (1961) is described. The frozen tissue is cut under liquid nitrogen with a razor blade outside the evaporator rather than inside with a cooled microtome. The conditions of the experiment do not favor sublimation, and it is proposed that the structure of the replica be explained by local faults in the cleavage plane which leaves structures, such as membranes, standing above the ice. Micrographs of replicas of glycerol-protected frozen small intestine of mouse prepared by the method are presented and the structural details they show are discussed. The problem of vapor-deposited contamination is discussed. It is concluded that this is a practical method for obtaining electron micrographs that are relatively free of artifact, and that further improvements may be expected from the use of rapidly frozen fresh tissue and a clean vacuum system, possibly of the ion-pumped type.

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Ultrastructural organization of cytoplasmic nucleoprotein in the exocrine pancreas cells

Cited by 50 publications

References 16 publications

Cellular components of Bacillus megaterium and their role in protein biosynthesis

Cellular components of Bacillus megaterium and their role in protein biosynthesis

The Staining of Thin Sections of Mouse Pancreas Prepared by the Fernández-Morán Helium Ii Freeze-Substitution Method

A Simple Freeze-Fracture Replication Method for Electron Microscopy

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