scholarly journals STUDIES BY ELECTRON MICROSCOPY OF THIN SECTIONS OF INFECTIOUS MYXOMATOSIS IN RABBITS

1952 ◽  
Vol 96 (4) ◽  
pp. 347-354 ◽  
Author(s):  
B. Epstein ◽  
Magdalena Reissig ◽  
E. De Robertis
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Host Cell ◽  
Internal Structure ◽  
Myxoma Virus ◽  
Intercellular Spaces ◽  
Thin Sections

Rabbits were inoculated with the C.P.M. strain of myxoma virus and the resulting subcutaneous tumors were fixed, embedded, and sectioned for observation with the electron microscope. Both round cells and the typical stellate myxomatous cells were observed in addition to changes in the collagen pattern at the intercellular spaces. The cytoplasm of the cells showed a great number of bodies of varying size and density, the largest of them having the size and other characteristics of the elementary bodies of the virus. Some of the bodies showed an internal structure, being formed by the tight clumping of small dense particles. Distribution curves of the diameter of the elementary bodies and of the smaller internal particles are presented. The morphological problems involved in the virus-host cell relationship are discussed in the case of the myxoma virus.

The morphogenesis of avian tendon

1956 ◽  
Vol 144 (917) ◽  
pp. 556-572 ◽  
Keyword(s):  
Electron Microscopy ◽  
Average Diameter ◽  
Relative Volume ◽  
Morphological Features ◽  
Collagen Fibrils ◽  
Intercellular Spaces ◽  
Intercellular Substance ◽  
Thin Sections ◽  
Cellular Components ◽  
Development Proceeds

Observations by electron microscopy on thin sections of the metatarsal tendon of embryonic fowls show that in the 8-day embryo the earliest definable collagen fibrils of 80 Å in diameter are intimately associated with the cytoplasm of the compact, apparently syncytial, cells of which the tendon rudiment is composed. As development proceeds, some intracytoplasmic groups of fibrils are distinguishable, but intercellular spaces also develop and these gradually become filled with fibrils; finally, bundles are formed and lie packed between the adjacent cells. Soon the extracellular organization predominates until at 20days the average diameter of the fibrils is 400 Å and the normal 640 Å periodicity of collagen has been achieved. The morphological features demonstrated have been correlated with histochemical data, and the possible function of the various cellular components in the formation of the intercellular substance has been discussed. By the use of sections in which fibrils have been cut exactly transverse to the bundle axis it has been shown that each fibril is invested by interfibrillar material. As the diameter of the fibrils increases with age the relative volume of interfibrillar material within a bundle diminishes; it is therefore concluded that this material must contain either collagen or the necessary precursors in order to account for the enlargement of the fibrils. Thus the interfibrillar material is of fundamental importance to the formation and growth of the collagen fibrils.

scholarly journals An Effective Method of Preparing Sections of Bacillus polymyxa Sporangia and Spores for Electron Microscopy

1960 ◽  
Vol 7 (2) ◽  
pp. 373-376 ◽  
Author(s):  
Pauline E. Holbert
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Epoxy Resins ◽  
Bacillus Polymyxa ◽  
Thin Sections ◽  
Similar Images ◽  
Embedding Medium ◽  
First Time ◽  
Diamond Knife

Bacillus polymyxa sporangia and spores were prepared for examination in the electron microscope by methods whose critical features were apparently: judicious use of vacuum, to encourage complete penetration of the embedding medium; the use of epoxy resins as embedding media; and cutting of the thin sections with a diamond knife. Electron micrographs of material prepared in this manner exhibit undeformed sporangial sections. Some of the structures revealed have been shown before, though perhaps less distinctly; other structures are revealed here for the first time. While this single study does not pretend to elucidate all the complexities of sporulation in bacteria, these and similar images should make this possible, and some mention of the preparatory techniques that lead to them seems advisable at this time.

Development of intercellular junctions in the pulmonary epithelium of the foetal lamb

1978 ◽  
Vol 32 (1) ◽  
pp. 307-324
Author(s):  
E.E. Schneeberger ◽  
D.V. Walters ◽  
R.E. Olver
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Tight Junctions ◽  
Lung Development ◽  
Light And Electron Microscopy ◽  
Intercellular Junctions ◽  
Intercellular Spaces ◽  
Thin Sections ◽  
Epithelial Tight Junctions ◽  
Foetal Lamb

The integrity of epithelial tight junctions in foetal mammalian lungs is essential to maintain the unique ionic composition of lung liquid, and to prevent leakage of serum proteins into peripheral air spaces. In the present study the development of intercellular junctions of the lining epithelium of foetal lamb lungs during gestation was examined by light and electron microscopy. Both thin sections and freeze-fracture replicas were examined by electron microscopy. By 39 days of gestation, epithelial tight junctions consist of a minimum of 3.1 +/− 1.6 (s.D.) and a maximum of 5.8 +/− 2.0 discontinuous rows of particles and short segments of strands on P face ridges and in complementary E face grooves, while from 58 to 76 days they are composed of a network of 4.3 +/− 1.6 to 7.7 +/− 1.9 focally interrupted P face strands. Complementary replicas show that many of the discontinuities on the P face are due to separation of junctional particles on to the E face during fracturing, and not to an absence of junctional particles. From 76 days to term, epithelial tight junctions (exclusive of upper airway epithelium which was not examined) resemble those of adult lungs, and consist of a continuous network of 4.5 +/− 2.0 to 7.5 +/− 2.5 P face strands and complementary particle-free grooves. Permeability measurements, published elsewhere, indicate that the epithelium is functionally ‘tight’ from 69 days onwards. Tight junctions in peripheral air-space epithelium, therefore, are structurally continuous and functionally ‘tight’ early in foetal lung development, and form seals at one end of long, narrow intercellular spaces; these features may be important for coupled ion and water transport. When the bounding epithelial cells become flattened, these narrow intercellular spaces remain intact as a result of complex interdigitations of adjacent cell membranes. Desmosomes were present throughout gestation near the abluminal side of the tight junctions and occasionally near the base of the intercellular space. These junctions may serve to connect cells to each other at a time when tight junctions may be mechanically weak. In addition, gap junctions are associated with tight junctions from the glandular through the canalicular stages of lung development. They disappear by 120 days when the epithelial cells are differentiated.

Electron microscope studies of the development of structure in Cheddar cheese

1974 ◽  
Vol 41 (3) ◽  
pp. 389-396 ◽  
Author(s):  
Alwyn M. Kimber ◽  
B. E. Brooker ◽  
D. G. Hobbs ◽  
J. H. Prentice
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Water Content ◽  
Cheddar Cheese ◽  
Incomplete Fusion ◽  
Casein Micelles ◽  
Thin Sections ◽  
Fat Globules ◽  
Granular Mass

SummaryThe development of structure in Cheddar cheese was followed using electron microscopy, of both thin sections and freeze-etched preparations. The casein micelles, at first separate, were seen to aggregate into a network, coalesce and finally form a granular mass. The fat globules, also separate at first, were gradually forced into clumps as a result of shrinkage of the casein network and incomplete fusion took place during ripening. Starter bacteria were seen trapped in the casein near the fat–casein interface, which was shown to be the region of highest water content in the mature cheese.

scholarly journals IDENTIFICATION OF GLYCOGEN IN ELECTRON MICROGRAPHS OF THIN TISSUE SECTIONS

1960 ◽  
Vol 8 (3) ◽  
pp. 575-589 ◽  
Author(s):  
Jean Paul Revel ◽  
Leonard Napolitano ◽  
Don W. Fawcett
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Animal Species ◽  
Short Exposure ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Microscopic Appearance ◽  
Tissue Sections ◽  
Lead Hydroxide ◽  
Electron Microscopic Appearance

The electron microscopic appearance of glycogen has been studied in the organs of several animal species. Glycogen almost always appears as roughly circular granules from 150 to 400 A in diameter. The intrinsic electron density of glycogen varies from tissue to tissue; however, treatment with lead hydroxide as described by Watson deeply stains the granules. Glycogen pellets were isolated from some of the tissues studied by centrifugation. Such pellets were shown to be glycogen by chemical and histochemical criteria. When thin sections of the pellet are examined under the electron microscope they can be seen to consist of densely packed granules similar to those found in the intact tissues. Such pellets are also stained for electron microscopy by short exposure to lead hydroxide.

Modification for Electron Miscroscopy of the Corbett Ammoniacal Silver Stain

1971 ◽  
Vol 29 ◽  
pp. 484-485
Author(s):  
Robert L. Corbett
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Light Microscopy ◽  
Low Power ◽  
Light And Electron Microscopy ◽  
Glass Slide ◽  
Silver Stain ◽  
Thin Sections ◽  
Silver Deposits ◽  
Ammoniacal Silver

The ammoniacal silver stain for light microscopy of plastic embedded sections has been adapted for use in electron microscopy. Since the silver will stain even very thin sections, i.e., silver and gold for light microscopy, and silver deposits are sufficiently electron dense to be seen in the electron microscope, the results are very useful for correlating light and electron microscopy. Compared to the conventional stains for electron microscopy which usually take over one-half hour, the silver procedure can be done in five minutes or less and thus provides a quick look at sections This stain has more contrast, so it is especially good for low power electron microscopy. The ability of the silver to stain very thin sections enables a correlation between light and electron microscopy in three ways. First, thin sections can be stained with silver on a glass slide and compared with immediately adjacent thin sections on grids stained the usual way for electron microscopy.

The Effect of Electron Microscopy on Pathological Diagnosis of Neoplasm

1990 ◽  
Vol 48 (3) ◽  
pp. 248-249
Author(s):  
Xiaojun Zhou ◽  
Taihe Zhang
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Frozen Section ◽  
Protein A ◽  
Functional Classification ◽  
Lead Citrate ◽  
Thin Sections ◽  
Tumor Tissues ◽  
Frozen Section Diagnosis

Although electron microscopy (EM) has contributed enormously to an understanding of the structural intricacies of tumor cells, the usefulness of EM in pathological diagnoses of neoplasms has not been readily appreciated by general pathologists. In the present study, 223 tumors submitted for EM diagnosis were analyzed in an attempt to gain further information concerning the contribution of EM to tumor diagnosis.223 neoplasms were submitted to EM for their final diagnoses when histopathological diagnoses were obscure, which represented about of the total number of surgical tumor specimens. Most specimens were taken at the time of frozen section diagnosis and a small number of tissues were originally fixed informaldehyde. All of tissues were fixed with buffered glutaradehyde, postfixed with osmium tetroxide and embedded in Epon 812. Ultrasections were made after semith in sections were examined to verify that representative tumor tissues were present. Thin sections were stained with uranium acetate and lead citrate, and examined under JEM-1200 EX electron microscope. In selected cases, mainly with neuroendocrine tumors, nickel grid-mounted sections were subjected to post embedding immunoelectron microscopy (IEM) using protein A-gold for more detailed functional classification. Protein A-gold probes were prepared as Wang and co-workers described.

An electron microscope study of the internal structure of casein micelles

1964 ◽  
Vol 31 (1) ◽  
pp. 121-123 ◽  
Author(s):  
P. D. Shimmin ◽  
R. D. Hill
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Internal Structure ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Casein Micelles ◽  
Thin Sections

SummaryA study of casein micelles was made with the electron microscope, using very thin sections cut from micelles embedded in Araldite. The micelles appear to be built up of units that are approximately spherical, about 100 Å in diameter and of about 300000 molecular weight.

Spermiogenesis of Eledone cirrhosa Lamarck (Cephalopoda, Octopoda)

1974 ◽  
Vol 186 (1083) ◽  
pp. 181-190 ◽  
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Vas Deferens ◽  
Mature Male ◽  
Axial Filament ◽  
Thin Sections ◽  
Sperm Tail ◽  
Mature Gamete ◽  
Microtubular System

Spermiogenesis in a mature male Eledone cirrhosa has been studied by means of phase con­trast and electron microscopy. Material from the testis was either studied alive or by means of thin sections. Material from the vas deferens and spermatophores was either studied live, in thin sections or in negatively stained preparations for the electron microscope. The spherical spermatid cells each become modified to give an elongate mature gamete. The gamete is remarkable in the size and complexity of its spiral head, the small size of the mid-piece and the length of the sperm tail. The acrosome is simple but helical. The flagellum originates in a single centriole; the ‘proximal’ centriole is lost. The axial filament consists of a ‘normal’ 9 + 2 microtubular system together with 9 accessory γ fibres; the γ fibres form a centriolar ring at their point of origin. Cytochemical tests show that there is a loosely packed deposit of glycogen throughout the length of the tail. There are no glycogen deposits within the mid-piece or the head.

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