scholarly journals THE INFLUENCE OF DEVELOPMENT ON THE NUMBER AND APPEARANCE OF SILVER GRAINS IN ELECTRON MICROSCOPIC RADIOAUTOGRAPHY

1967 ◽  
Vol 15 (9) ◽  
pp. 501-515 ◽  
Author(s):  
BEATRIX MARKUS KOPRIWA
Keyword(s):  
Resolving Power ◽  
Silver Bromide ◽  
Grain Development ◽  
Electron Microscopic ◽  
Duration Of Action ◽  
Small Grains ◽  
Silver Grains ◽  
Electron Microscopic Radioautography ◽  
Selection Of ◽  
Duration Of Development

Under conditions similar to those in electron microscopic radioautography, the development of three different nuclear track emulsions—Ilford L4, Gevaert 307 and Kodak NTE—was investigated by varying the type of developer, duration of action and temperature. These three factors influence: (1) the number of silver grains produced from exposed silver bromide crystals and, therefore, the sensitivity of the emulsion; (2) the production of a few silver grains from silver bromide crystals, unexposed to radiation from the specimen, that is, the background fog; and (3) the size and shape of the developed silver grains, thus influencing the resolving power. The developed silver grains increase in number and in size with increasing duration of development. After complete development in most developers, the silver grains consist of highly convoluted silver filaments and are 2 or 3 times as large as the original silver bromide crystals. However, small grains may be obtained by brief development in Loveland's and p-phenylenediamine developers, in which case only development centers are revealed. Such small grain development improves resolving power, but decreases the number of developed silver grains, thus reducing sensitivity. The most satisfactory emulsion-developer combination under the conditions of the experiment appears to be Gevaert 307 emulsion developed for 2 min in D-19b. Data are also presented to facilitate the selection of the optimal emulsion-developer combination for various experimental situations.

scholarly journals A SEMIAUTOMATIC INSTRUMENT FOR THE RADIOAUTOGRAPHIC COATING TECHNIQUE

1966 ◽  
Vol 14 (12) ◽  
pp. 923-928 ◽  
Author(s):  
BEATRIX MARKUS KOPRIWA
Keyword(s):  
Silver Bromide ◽  
Electron Microscopic ◽  
Simple Method ◽  
Nuclear Track Emulsion ◽  
Withdrawal Speed ◽  
Emulsion Layer ◽  
Semiautomatic Instrument ◽  
Mechanical Coating ◽  
Electron Microscopic Radioautography ◽  
Selection Of

By means of a mechanical coating instrument a fast, simple method to coat specimens with liquid nuclear track emulsion has been devised for quantitative light and electron microscopic radioautography. In both cases, the section is mounted on a glass slide. After the vertically held slide has been immersed in the melted emulsion, the instrument withdraws it at a slow, constant speed. As a result, the specimen is coated with a thin, uniform emulsion layer composed of homogeneously distributed silver bromide crystals. The thickness of the emulsion coat may be standardized by selection of an optimal combination of emulsion dilution, temperature and withdrawal speed.

scholarly journals LIGHT AND ELECTRON MICROSCOPIC RADIOAUTOGRAPHY OF HEPATIC CELL NUCLEOLI IN MICE TREATED WITH ACTINOMYCIN D

1967 ◽  
Vol 33 (3) ◽  
pp. 489-496 ◽  
Author(s):  
J. C. H. de Man ◽  
N. J. A. Noorduyn
Keyword(s):  
Orotic Acid ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
Electron Microscopic ◽  
Granular Component ◽  
Hepatic Cells ◽  
Progressive Loss ◽  
Nucleolar Rna ◽  
Silver Grains ◽  
Electron Microscopic Radioautography

Nucleolar partition induced by actinomycin D was used to demonstrate some aspects of nucleolar RNA synthesis and release in mouse hepatic cells, with light and electron microscopic radioautography. The effect of the drug on RNA synthesis and nucleolar morphology was studied when actinomycin D treatment preceded labeling with tritiated orotic acid. Nucleolar partition, consisting of a segegration into granular and fibrillar parts was visible if a dosage of 25 µg of actinomycin D was used, but nucleolar RNA was still synthesized. After a dosage of 400 µg of actinomycin D, nucleolar RNA synthesis was completely stopped If labeling with tritiated orotic acid preceded treatment with 400 µg of actinomycin D, labeled nucleolar RNA was present 15 min after actinomycin D treatment while high resolution radioautography showed an association of silver grains with the granular component. At 30 min after actinomicyn D treatment all labeling was lost. Since labeling was associated with the granular component the progressive loss of label as a result of actinomycin D treatment indicated a release of nucleolar granules. The correlation between this release and the loss of 28S RNA from actinomycin D treated nucleoli as described in the literature is discussed.

scholarly journals LA SYNTHÈSE DE L'ADN MITOCHONDRIAL CHEZ TETRAHYMENA PYRIFORMIS

1968 ◽  
Vol 39 (2) ◽  
pp. 369-381 ◽  
Author(s):  
Renée Charret ◽  
Jean André
Keyword(s):  
Mitochondrial Dna ◽  
Great Majority ◽  
Tetrahymena Pyriformis ◽  
Logarithmic Phase ◽  
Time Interval ◽  
Electron Microscopic ◽  
Mitochondrial Population ◽  
A Cell ◽  
Silver Grains ◽  
Electron Microscopic Radioautography

Electron microscopic radioautography has been used to study the synthesis of mitochondrial DNA after incorporation of thymidine-3H by cultures in logarithmic phase of Tetrahymena pyriformis during periods ranging from 15 min to 12 hr. The great majority of silver grains are distributed over the macronuclei, the micronuclei, and the mitochondria. The intensity of the label over the entire mitochondrial population is a function of the length of the incubation period within the time interval considered. The intensity of the mitochondrial label was compared with that of the nuclear label. Mitochondria incorporate at the same rate whether the nuclei are synthesizing or not. This persistence of mitochondrial incorporation in the absence of nuclear incorporation excludes the hypothesis of a nuclear origin for mitochondrial DNA. We are not able to determine whether the apparent continuity of synthesis in the entire mitochondrial population of a cell actually represents a series of asynchronous discontinuities.

scholarly journals Appendix: Radioautographic localization of labelled proteins after incubation of guinea-pig islets of Langerhans with [3H]tryptophan

1974 ◽  
Vol 140 (1) ◽  
pp. 22-23 ◽  
Author(s):  
S. L. Howell ◽  
C. Hellerström ◽  
M. Whitfield
Keyword(s):  
B Cells ◽  
Guinea Pig ◽  
B Cell ◽  
Islets Of Langerhans ◽  
Electron Microscopic ◽  
Storage Granules ◽  
Silver Grains ◽  
Electron Microscopic Radioautography ◽  
Significant Concentration

An analysis was made by electron-microscopic radioautography of the distribution of silver grains over storage granules of A2 and B cells after incubation of isolated guinea-pig islets of Langerhans for 17h in the presence of [3H]tryptophan. A significant concentration of labelled proteins was present in the A2 cell, but not in the B-cell granules.

Electron microscopic radioautographic study of glycoprotein biosynthesis and renewal in the renal glomeruli of the rat

1978 ◽  
Vol 36 (2) ◽  
pp. 476-477
Author(s):  
A. Haddad ◽  
J-J. Lachat ◽  
R. P. Gonçalves
Keyword(s):  
Renal Cortex ◽  
Mesangial Cells ◽  
Electron Microscopic ◽  
Time Intervals ◽  
Light Microscope Level ◽  
Thin Sections ◽  
Main Site ◽  
Renal Glomeruli ◽  
Silver Grains ◽  
Electron Microscopic Radioautography

Biosynthesis, migration and renewal of glycoproteins were studied by radioautography in the renal glomeruli after administering L-3H-fucose to rats which were killed at several time intervals after injection, by perfusion of glutaraldehyde through the abdominal aorta. Small pieces of the kidney were post fixed in 0s04, dehydrated and embedded in Epon 812. Semithin and thin sections of the renal cortex were processed for light and electron microscopic radioautography, respectively. At the light microscope level (Fig. 1) it was observed that the main site of incorporation of 3H-fucose into glycoproteins was the paranuclear region of the visceral epithelial cells (podocytes). Weak paranuclear radioautographic reactions were also observed in endothelial and mesangial cells at 10 minutes after injection. At the longer time intervals these paranuclear reactions disappeared and the silver grains were mostly overlying the several components of the capillary wall. Silver grain counts showed that the peak of the silver grain density over the glomeruli occurred at 4 hours after injection; by 14 days the radioautographic reactions were almost negligible.

Preparatory Procedures for Electron Microscopic Analysis at the Molecular Level of Resolution

1978 ◽  
Vol 36 (3) ◽  
pp. 516-520
Author(s):  
F.J. Sjostrand
Keyword(s):  
Electron Microscope ◽  
Molecular Level ◽  
Microscopic Analysis ◽  
Resolving Power ◽  
Cellular Structures ◽  
Electron Microscopic ◽  
Systematic Analysis ◽  
Technical Developments ◽  
Thin Sectioning ◽  
Obvious Reason

In the 1940's and 1950's electron microscopy conferences were attended with everybody interested in learning about the latest technical developments for one very obvious reason. There was the electron microscope with its outstanding performance but nobody could make very much use of it because we were lacking proper techniques to prepare biological specimens. The development of the thin sectioning technique with its perfectioning in 1952 changed the situation and systematic analysis of the structure of cells could now be pursued. Since then electron microscopists have in general become satisfied with the level of resolution at which cellular structures can be analyzed when applying this technique. There has been little interest in trying to push the limit of resolution closer to that determined by the resolving power of the electron microscope.

A simplified method of emulsion coating and development for quantitative electron microscopic radioautography

1978 ◽  
Vol 36 (2) ◽  
pp. 64-65
Author(s):  
K. Yoshida ◽  
F. Murata ◽  
S. Ohno ◽  
T. Nagata
Keyword(s):  
Mass Production ◽  
Identical Condition ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Simplified Method ◽  
Complicated Process ◽  
Critical Problems ◽  
Electron Microscopic Radioautography ◽  
Quantitative Radioautography

IntroductionSeveral methods of mounting emulsion for radioautography at the electron microscopic level have been reported. From the viewpoint of quantitative radioautography, however, there are many critical problems in the procedure to produce radioautographs. For example, it is necessary to apply and develop emulsions in several experimental groups under an identical condition. Moreover, it is necessary to treat a lot of grids at the same time in the dark room for statistical analysis. Since the complicated process and technical difficulties in these procedures are inadequate to conduct a quantitative analysis of many radioautographs at once, many factors may bring about unexpected results. In order to improve these complicated procedures, a simplified dropping method for mass production of radioautographs under an identical condition was previously reported. However, this procedure was not completely satisfactory from the viewpoint of emulsion homogeneity. This paper reports another improved procedure employing wire loops.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Distribution of newly formed hepatic glycogen in adrenalectomized rats as observed by radioautography after injection of 3H-galactose

1984 ◽  
Vol 42 ◽  
pp. 228-229
Author(s):  
J. E. Michaels ◽  
J. T. Hung ◽  
E. L. Cardell ◽  
R. R. Cardell
Keyword(s):  
Glycogen Synthesis ◽  
Hepatic Glycogen ◽  
Electron Microscopic ◽  
Routine Procedures ◽  
Silver Grains ◽  
Synthetic Glucocorticoid ◽  
Adrenalectomized Rats

In order to study early events of glycogen synthesis, we have used adrenalectomized (ADX) rats fasted overnight and injected with the synthetic glucocorticoid dexamethasone (DEX) to stimulate glycogen synthesis. Rats were given DEX 0-5 hr prior to sacrifice and injected with 2 mCi 3H-galactose 1 hr prior to sacrifice. Liver was prepared for light (LM) and electron microscopic (EM) radioautography by routine procedures.The concentration of silver grains over hepatic cytoplasm was measured in LM radioautographs using a Zeiss Videoplan. The hepatocytes were categorized as unlabeled if no silver grains (gr) were present, lightly labeled (<10gr/100 μm2 cytoplasm) or intensely labeled (>10 gr/1002 μm cytoplasm). Although very few hepatocytes showed heavy labeling after 1 hr treatment with DEX, by 2 hr after DEX treatment 8% of the cells distributed throughout the lobule were intensely labeled.

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