ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02079.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02080.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SYNOPSISA procedure for the application of cytochemical techniques directly on ultrathin sections for electron microscopy has been developed with the use of water‐soluble plastics, which act both as dehydrating agents and embedding media. Our approach has been to selectively extract proteins and nucleic acids from ultrathin sections of cells and viruses by specific enzyme hydrolysis. Glycol methacrylate is particularly useful as a component of the embedding medium because it enhances the penetrability of the enzyme into the section and preserves the biological materials in such a way that they remain susceptible to enzymic digestion. Various degrees of morphological preservation of ultrastructure are obtained with the aldehyde fixatives, formalin, acrplein, and glutaraldehyde, followed by. embedding in glycol methacrylate and the choice of fixative, at present, depends on the system which is to be studied. It is believed that the proposed method can be developed further and be used for other approaches to ultrastructural cytochemistr

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02081.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

So far autoradiography has mainly been used at the level of light microscopy and the theory of autoradiography was developed for this type of work. Whatever the intended application, the problems involved can be grouped under (a) resolving power, (b) sensitivity, and (c) technique.An autoradiograph is prepared by bringing a specimen containing some radioactive material in contact with a photographic emulsion and storing the preparation in the dark for exposure. During the time of exposure some of the radioactive material will decay and the ionizing radiations emitted will produce latent images in the emulsion. After photographic processing the developed image will appear as an accumulation of silver grains which are seen as round black spots under the light microscope and as filamentous structures in the electron microscope.

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02082.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SYNOPSISObservations made on the influence of the fixative on staining of thin tissue sections for electron microscopy permit the following statements:After acrolein fixation it is possible to demonstrate basic proteins of the chromatin by silver impregnation. The staining appears to be mediated by the product of the reaction between the fixative and the imidazole groups of histidine.In the absence of reduced osmium (fixation by formol or acrolein or preliminary oxidation of sections of osmium‐fixed tissue) conventional lead methods result in a selective staining of the ribonucleoproteins. Under the same conditions, a selective staining of the plasma membrane (or an associated substance) can be achieved by phosphotungstic acid.After formol or acrolein fixation, uranyl acetate (at pH 4.5 to 5) stains the desoxyribonucleoproteins more intensely than the ribonucleoproteins. The strongest differentiation between the nucleoproteins is found to occur after formol‐osmium fixat

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02083.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02084.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

SYNOPSISThe localization and transformation of the immobilization antigens ofParamecium aureliawere studied with the use of ferritin‐conjugated antibody. The reaction was extremely specific, ferritin granules being found only on the pellicle and cilia of homologous animals. In the transformation from one antigenic type to another, ferritin granules, conjugated with antibody specific for the “new” antigen, appeared initially on the pellicle and subsequently on the cilia.An electron‐dense counterstain, of potassium permanganate and uranyl acetate, not only increased the detail of the structure of the organism, but also stained the absorbed globulin of the specific antibody as a thick fuzz on pellicle and cilia. This fuzz, unlike the ferritin granules, was clearly visible at very low magnifications of the electron microscope. This gave a quick scanning method, especially useful in transformation experiments, when various stages could be quickly scanned for the first appearance of globul

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02085.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Asatisfactorytechnique has been developed which allows sections through selected mitotic cells of human or newt tissue cultures to be examined by electron microscopy. The cells are grown on carbon‐coated cover‐slips, selected, fixed, and marked whilst being observed in the phase‐contrast light microscope, and embedded in Araldite. The cover‐slip is stripped off when the Araldite block has hardened. The required cell is identified again under phase contrast, and then sectioned using a diamond knife which allows serial sections beginning at the block face to be cut with assurance. Sections are picked up on special grids with a large central hole permitting the whole of several serial sections to be viewed without obstruction. The chromosomes are stained by immersing the grids in 2 p.c. aqueous uranyl acetate, often followed by further staining with lead hydroxide. Some features of their morphology were described, but they show little evidence of highly organized fine structure immediately below the limit of resolution of the light mic

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02086.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

Autoradiographyat the ultrastructural level has made considerable progress during the past year and soon it will be one of the routine techniques of electron microscopy. We wish to present here a few theoretical and technical considerations. In the theoretical domain we shall propose a geometrical model, which suggests certain reflections on the power of resolution and sensitivity. In the technical domain we shall present the details of the method which we now employ routinely, and introduce a new small‐grain photographic emulsion which improves considerably the resolving power of electron autoradiograph

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02087.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY

摘要:

AbstractInextending cytochemical staining methods for enzyme localization to the subcellular level, more exacting conditions have to be met than those adequate for light microscopy, since in addition to preserving enzymic activity, cellular fine structure has to be maintained during preparation and staining of specimens. In addition, the stain must be able to resist dissolution or displacement by dehydrating and embedding media and be sufficiently electron‐scattering to be detectable in the electron microscope.Standard osmium‐tetroxide fixation seriously inhibits the activity of many enzymes and causes differential inhibition in some cases (Holt&Hicks, 1962b), thus leading to false localization of activity. Both buffered formol‐sucrose (Holt&Hicks, 1961a) and other aldehydes, such as glutaraldehyde (Sabatini, Bensch&Barrnett, 1962) give good preservation of fine structure and of the activity of several enzymes, but it is necessary to post‐fix aldehyde‐fixed tissues in osmium tetroxide before embedding for electron m

ISSN:0368-3974    

DOI:10.1111/j.1365-2818.1963.tb02088.x

出版商:Blackwell Publishing Ltd    

年代:1963

数据来源: WILEY