scholarly journals FINE STRUCTURAL CHANGES IN THE FLAGELLUM OF THE SPERMATID IN EXPERIMENTAL CRYPTORCHIDISM OF THE RAT

1963 ◽  
Vol 18 (2) ◽  
pp. 337-344 ◽  
Author(s):  
Toshio Nagano
Keyword(s):  
Electron Microscope ◽  
Cross Sections ◽  
Osmium Tetroxide ◽  
Structural Changes ◽  
Abdominal Cavity ◽  
Main Axis ◽  
The Other ◽  
Experimental Conditions ◽  
Fibrous Sheath ◽  
Axial Filament

Rat testes were confined to the abdominal cavity by operation. After 1 to 26 days they were excised, fixed with osmium tetroxide, sectioned, and examined with the electron microscope. Changes in the axial filament complex of the spermatid flagellum appeared 2 days after operation, and the arrangement of filaments in the middle- and main pieces of some spermatid tails was disordered as compared to the 9 + 2 filament arrangement in the tails of the control spermatids and in other flagella and cilia. In cross-sections, the filaments in the experimental material were nine or less in number, and each of them was single and dense. Occasionally some were double, and in those instances one filament was dense and the other was light and tubular. The central filaments were obscure. In longitudinal sections,the filaments were not parallel to the main axis of the flagella or to each other. It was assumed that the central filaments were more sensitive to the experimental conditions than the peripheral pairs of filaments. Furthermore, the light filaments of the peripheral pairs were more sensitive than the dense filaments. Besides the axial filament complex, the fibrous sheath which surrounds it in the main piece was also changed. The plasma membrane of the changed flagella disappeared or became fragmented.

scholarly journals THE SUBCELLULAR LOCALIZATION OF CALCIUM ION IN MAMMALIAN MYOCARDIUM

1969 ◽  
Vol 41 (2) ◽  
pp. 401-423 ◽  
Author(s):  
Marianne J. Legato ◽  
Glenn A. Langer
Keyword(s):  
Electron Microscope ◽  
Calcium Ion ◽  
Muscle Function ◽  
Osmium Tetroxide ◽  
Vascular Supply ◽  
The Other ◽  
Papillary Muscles ◽  
Mammalian Myocardium ◽  
Tissue Sodium ◽  
Potassium Pyroantimonate

This study was designed to investigate the proposition that subcellular calcium is sequestered in specific sites in mammalian myocardium. 29 functioning dog papillary muscles were fixed through the intact vascular supply by means of osmium tetroxide containing a 2% concentration of potassium pyroantimonate (K2H2Sb2O7·4H2O). Tissue examined in the electron microscope showed a consistent and reproducible localization of the electron-opaque pyroantimonate salts of sodium and calcium to distinct sites in the tissue. Sodium pyroantimonate was found exclusively in the extracellular space and clustered at the sarcolemmal membrane. Calcium pyroantimonate, on the other hand, identified primarily by its susceptibility to removal by chelation with EGTA and EDTA, was consistently found densely concentrated in the lateral sacs of the sarcoplasmic reticulum and over the sarcomeric I bands. M zones were virtually free of precipitate. The implications of these findings with respect to various parameters of muscle function are discussed.

Microscopical Characterization of Grafted Cotton Fibers

1971 ◽  
Vol 29 ◽  
pp. 230-231
Author(s):  
Wilton R. Goynes
Keyword(s):  
Electron Microscope ◽  
Cross Sections ◽  
Structural Changes ◽  
Cotton Fibers ◽  
Transmission Electron ◽  
Hardy Cross ◽  
Radiation Induced ◽  
Physical Tests ◽  
Ultrathin Sections ◽  
Recovery Angle

Radiation induced graft polymerization of the cellulose of cotton fibers with various other polymers produces textile fibers with new properties. Chemical analysis and physical tests are used to determine changes in such properties as breaking strength, wrinkle recovery angle, and resistance to abrasion. While such tests give reliable evaluations of the overall nature of any improvement, they give little information on what changes actually occurred in the fiber itself. One means of obtaining this information is through microscopical observations.Penetration and reaction of the polymer within yarns and fibers can be tested by cutting Hardy cross sections of the fibers after they have been dyed with a stain specific for the reacted polymer. More detailed information can be obtained from ultrathin sections, using the transmission electron microscope. Structural changes often occur which are obvious from comparison of cross sections of untreated and treated fibers. Use of the scanning electron microscope permits evaluation of changes in surface features of fabrics and individual fibers.

scholarly journals Electron Microscopy of Retinal Photoreceptors

1960 ◽  
Vol 7 (3) ◽  
pp. 493-497 ◽  
Author(s):  
Arnaldo Lasansky ◽  
Eduardo de Robertis
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Electron Microscope ◽  
Outer Segment ◽  
Osmium Tetroxide ◽  
The Other ◽  
Rod Outer Segments ◽  
Outer Segments ◽  
Retinal Photoreceptors ◽  
L1 And L2

The fine structure of the cone and rod outer segments of the toad was studied under the electron microscope after fixation in osmium tetroxide and fixation in formaldehyde followed by chromation. In the OsO4-fixed specimens, the rod outer segment appears to be built of a stack of lobulated flattened sacs, each of which is made of two membranes of about 40 A separated by an innerspace of about 30 A. The distance between the rod sacs is about 50 A. The sacs in the cone outer segment are originated by the folding of a continuous membrane. The thickness of the membranes and width of the spaces between the cone sacs is the same as in rod, but the sac innerspace is slightly narrower in the cone (∼ 20 A). After fixation in formaldehyde and chromation, two different dense lines (l1 and l2) separated by spaces of less density appear. One of the lines, l1, has a thickness of 70 A and is less dense than the other, l2, which is 30 A thick. The correlation of the patterns obtained with both fixatives is considered and two possible interpretations are given. The possibility that l2 is related to a soluble phospholipid component is discussed. It is suggested that the outer segments have a paracrystallin organization similar to that found in myelin.

scholarly journals FINE STRUCTURE OF THE CILIARY EPITHELIUM OF THE RABBIT, WITH PARTICULAR REFERENCE TO "INFOLDED MEMBRANES," "VESICLES," AND THE EFFECTS OF DIAMOX

1963 ◽  
Vol 17 (3) ◽  
pp. 641-659 ◽  
Author(s):  
John Mcd. Tormey
Keyword(s):  
Osmium Tetroxide ◽  
Plasma Membranes ◽  
Structural Changes ◽  
Secretory Activity ◽  
Structural Features ◽  
Ciliary Epithelium ◽  
Albino Rabbit ◽  
Serial Sections ◽  
Experimental Conditions ◽  
Tubular Endoplasmic Reticulum

The structure of the ciliary epithelium of the adult albino rabbit has been studied by electron microscopy. Material was fixed in osmium tetroxide and embedded in epoxy resins. Two hitherto unappreciated features of the non-pigmented epithelial layer are described. First, the "infolded plasma membranes" described by previous workers are shown by serial sections to be projections or interdigitations from adjacent cells. Second, the "rows of vesicles" described by previous workers are shown by serial sections to be part of an unusual form of smooth-surfaced tubular endoplasmic reticulum. The tubules are highly convoluted and extensively interconnected. They are arranged in sheets, so that a cross-section through a sheet gives the appearance of a row of vesicles. The other structural features of the ciliary epithelium are also described. Previous workers have reported that Diamox, which inhibits the secretory activity of the epithelium, causes profound structural changes. An effort has been made to confirm these reports under carefully controlled experimental conditions. It was found that secretion could be inhibited by a maximally effective dose of Diamox without the occurrence of any detectable structural changes. The physiological significance of these findings is discussed.

X-ray microanalytical and enzyme-cytochemical study on vesical malacoplakia

1978 ◽  
Vol 36 (2) ◽  
pp. 646-647
Author(s):  
Masami Hokano ◽  
Tsunao Oh-I ◽  
Yoshie Narita ◽  
Hiroshi Sassa ◽  
Saburo Suzuki
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Granulomatous Inflammation ◽  
Uranyl Acetate ◽  
The Other ◽  
Lead Citrate ◽  
Cytochemical Study ◽  
X Ray ◽  
Ultrathin Sections

Malacoplakia is a kind of granulomatous inflammation and characterized by the presence of calcium-stain positive granules (Michaelis-Gutmann bodies, hereinafter abbreviated as M-G bodies ) in the macrophages.In this report we want to say about the following articles:the ultrastruc tural findings in four cases of vesical malacoplakia;the ultrastructural morphogenesis of the M-G bodies;X-ray microanalytical studies which examine the change of the chemical component of M-G bodies, according to their developing stages; andacid phosphatase activity of lysosome within the malacoplakic macrophages.Biopsy materials taken from four cases with vesical malacoplakia were divided into 2 parts; one for a light microscopy and the other for an electron microscopy. The specimen for an electron microscopy was fixed in glutaraldehyde and osmium tetroxide, dehydrated in ethanol and then embedded in Epon 812. Ultrathin sections were doublestained with lead citrate and uranyl acetate and then subjected to routin TEM observation. For X-ray microanalysis was mounted an energy dispersive X-ray microanalyzer on a JEM-100 C type electron microscope. Ultrathin sections for microanalysis were cut 100-200nm thich and not stained.

scholarly journals Assessment of the Effect of Secondary Fixation on the Structure of Meat Products Prepared for Scanning Electron Microscopy

Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 487
Author(s):  
Hana Běhalová ◽  
Bohuslava Tremlová ◽  
Ludmila Kalčáková ◽  
Matej Pospiech ◽  
Dani Dordevic
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Microscope ◽  
Connective Tissue ◽  
Scanning Electron Microscope ◽  
Osmium Tetroxide ◽  
Structural Changes ◽  
Meat Products ◽  
Chemical Fixation ◽  
Scanning Electron

The aim of the research was to verify the necessity of secondary fixation with osmium tetroxide in various types of meat products and evaluation of structural changes of products using different fixation procedures. The material for the study consisted of 11 types of meat products that were analyzed using a scanning electron microscope (SEM) with two different methods of chemical fixation. The first method included the usual processing of biological samples: glutaraldehyde primary fixation, the use of a buffer, secondary fixation by osmium tetroxide (OsO4), buffer, and dehydration using ethanol of increasing concentrations. The second method comprised the glutaraldehyde primary fixation and dehydration using the ethanol of increasing concentrations only. The results unambiguously suggest that the main difference between these methods is in fixation and visibility of fat. Our analysis principally suggests that fixation of the product with OsO4 allows the tracking of all components (fat droplets, muscle fibers, connective tissue) in meat products. At the same time, our results also support the possibility that the secondary fixation can be skipped during the analysis, where the main objection is an observation of lipid-free structures of the meat products (e.g., connection between muscle and starches or spices) or meat products with an insignificant amount of fat.

The bandicoot spermatozoon: an electron microscope study of the tail

1959 ◽  
Vol 150 (938) ◽  
pp. 24-42 ◽  
Keyword(s):  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Minor Axis ◽  
The Other ◽  
Morphological Evidence ◽  
Axial Filament ◽  
Middle Piece ◽  
Tail Sheath ◽  
Axial Ring

An electron microscope study has been made of the tail of the bandicoot spermatozoon ( Perameles nasuta Geoffroi). The shape of the sperm head makes it possible to define dorsal, ventral, right and left surfaces on the head. The orientation of structures in the middle piece and tail relative to these head surfaces permits identification of the corresponding middle piece and tail surfaces. Dorso-ventral and transverse axes may be assigned to the spermatozoon. Major and minor axes are recognizable in transverse sections of the middle piece and tail. The tail contains two groups of fibrils, the axial filament complex and the peripheral fibrils. The axial filament complex consists of two central fibrils lying in the transverse axis of the head which are surrounded by an axial ring of nine fibrils not equidistant from each other. The axis of symmetry of the axial filament complex is in the dorso-ventral axis of the spermatozoon. The much thicker peripheral fibrils, of which there are nine, are found at varying but considerable distances from the axial ring of fibrils. They also are not equidistant from one another. Two of them differ from the other seven in shape and lie on the minor axis of the tail; four of the remaining seven lie on the dorsal half and three on the ventral half of the tail. Seven of the peripheral fibrils are connected with the homologous members of the axial filament complex by connecting laminae, which consist of laminar filaments passing between the two types of fibrils. One lamina has only one set of filaments. The other six have two sets of parallel filaments. The tail fibrils are enclosed by a spiral sheath which shows pronounced thickenings at both ends of the minor axis of the tail. Vacuoles, arranged in a characteristic way, are located within these thickenings. Thin processes connect the spiral sheath with two of the fibrils in the axial filament complex. A trilaminar membrane separates the spiral sheath from the tail sheath, which is an electron-transparent structure bounded by a single membrane. The possibility of establishing a functional relationship between the tail structures and sperm movement is discussed. The morphological evidence suggests that the tail beat is in the dorso-ventral plane.

Evaluation of single-electron movies of glutamine synthetase molecules

1983 ◽  
Vol 41 ◽  
pp. 280-281
Author(s):  
W. Kunath ◽  
E. Zeitler ◽  
M. Kessel
Keyword(s):  
Electron Microscope ◽  
Glutamine Synthetase ◽  
Electron Irradiation ◽  
Structural Damage ◽  
Structural Changes ◽  
Single Electron ◽  
Continuous Series ◽  
Digital Recording ◽  
Recording Device ◽  
Low Exposure

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.

The Alteration of the Pore Spaces in Sandstones

1973 ◽  
Vol 31 ◽  
pp. 210-211
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
The Other ◽  
Coarse Grained ◽  
Depositional Fabric ◽  
Soluble Components ◽  
Scanning Electron ◽  
Shape And Size

The pore spaces in sandstones are the result of the original depositional fabric and the degree of post-depositional alteration that the rock has experienced. The largest pore volumes are present in coarse-grained, well-sorted materials with high sphericity. The chief mechanisms which alter the shape and size of the pores are precipitation of cementing agents and the dissolution of soluble components. Each process may operate alone or in combination with the other, or there may be several generations of cementation and solution.The scanning electron microscope has ‘been used in this study to reveal the morphology of the pore spaces in a variety of moderate porosity, orthoquartzites.

Further Observations on the Virus of Epizootic Diarrhea of Infant Mice. An Electron Microscopic Study

1967 ◽  
Vol 25 ◽  
pp. 110-111
Author(s):  
W. G. Banfield ◽  
G. Kasnic ◽  
J. H. Blackwell
Keyword(s):  
Electron Microscope ◽  
Infected Cell ◽  
Microscopic Study ◽  
Intestinal Epithelium ◽  
Ultrastructural Study ◽  
Osmium Tetroxide ◽  
Lead Citrate ◽  
Electron Microscopic ◽  
Virus Particles ◽  
Infected Cells

An ultrastructural study of the intestinal epithelium of mice infected with the agent of epizootic diarrhea of infant mice (EDIM virus) was first performed by Adams and Kraft. We have extended their observations and have found developmental forms of the virus and associated structures not reported by them.Three-day-old NLM strain mice were infected with EDIM virus and killed 48 to 168 hours later. Specimens of bowel were fixed in glutaraldehyde, post fixed in osmium tetroxide and embedded in epon. Sections were stained with uranyl magnesium acetate followed by lead citrate and examined in an updated RCA EMU-3F electron microscope.The cells containing virus particles (infected) are at the tips of the villi and occur throughout the intestine from duodenum through colon. All developmental forms of the virus are present from 48 to 168 hours after infection. Figure 1 is of cells without virus particles and figure 2 is of an infected cell. The nucleus and cytoplasm of the infected cells appear clearer than the cells without virus particles.

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