scholarly journals AN ELECTRON MICROSCOPE STUDY OF CANINE CARDIAC MYOSIN AND SOME OF ITS AGGREGATES

1966 ◽  
Vol 28 (2) ◽  
pp. 375-389 ◽  
Author(s):  
John A. Carney ◽  
Arnold L. Brown

The morphology of the canine cardiac myosin molecule has been investigated in the electron microscope with Hall's mica-replica technique. The molecule is an elongated rod (shaft) of nonuniform diameter with a globular expansion (head) on one end. Statistical analysis of the lengths of 1908 molecules showed that the mean length was 1610 ± 250 A; the mean length of the head was 210 ± 20 A; and the diameter of the head and that of the shaft were 35 to 40 and 15 to 20 A, respectively. About one-third of the molecules had single or multiple, fairly sharp, angulations along their shafts. Rarely, some details of the substructure of the molecule have been observed. Large, spindle-shaped aggregates, measuring 0.5 to 1 µ in length and 50 to 100 A in diameter, were produced by dilution of the myosin solutions. These aggregates were readily visualized in the electron microscope by means of Huxley's negative-staining technique. Projections often were visible along the length of the aggregates except at a central zone where they were frequently absent. The aggregates resembled the thick myofilaments of the myocardium and appeared similar to those produced by Huxley from skeletal myosin solutions.

2015 ◽  
Vol 74 (6) ◽  
pp. 718-721 ◽  
Author(s):  
Corrado Rubino ◽  
Vittorio Mazzarello ◽  
Mario Faenza ◽  
Andrea Montella ◽  
Fabio Santanelli ◽  
...  

1949 ◽  
Vol 90 (4) ◽  
pp. 283-290 ◽  
Author(s):  
E. De Robertis ◽  
F. O Schmitt

Sciatic nerves of rhesus monkeys infected with CAM and Wis. '45 strains of human poliomyelitis virus were fixed in formalin, sectioned, fragmented, and examined in the electron microscope. Most of the neurotubules of nerves infected with the CAM strain have normal appearance but a very small number show the presence of dense particles irregularly aligned within the edges of the neurotubules. The diameters of the particles range between 160 and 500 Å, the mean being 330 Å. The particles were found in regions along the nerve which varied with the time after infection, indicating a central movement of the morphological alteration of the order of 2 mm. per hour. Relatively abundant dense particulate material was found in nerves infected with Wis. '45 strain virus and the particles were chiefly attached to the edges of the neurotubules and in the adjacent areas of the field. The dense particles appear to be associated with the virus infection but no further characterization is possible at this time.


An electron microscope study of evaporating liquid lead particles, formed on carbon substrates by nucleation from the vapour, has led to a confirmation of the Kelvin equation which relates equilibrium vapour pressure to surface curvature. Observations of the same kind made on particles of evaporating solid silver have produced evaporation curves similar to those for lead. Interpretation of these curves in terms of the Kelvin equation for solids has yielded a value for the mean surface energy of silver of 1.20 ± 0.06 J m -2 (1200 ± 60 erg cm -2 ) at 1005 ± 25 K.


Author(s):  
O. E. Bradfute ◽  
R. E. Whitmoyer ◽  
L. R. Nault

A pathogen transmitted by the eriophyid mite, Aceria tulipae, infects a number of Gramineae producing symptoms similar to wheat spot mosaic virus (1). An electron microscope study of leaf ultrastructure from systemically infected Zea mays, Hordeum vulgare, and Triticum aestivum showed the presence of ovoid, double membrane bodies (0.1 - 0.2 microns) in the cytoplasm of parenchyma, phloem and epidermis cells (Fig. 1 ).


Author(s):  
A. Campos ◽  
J. Vilches ◽  
J. Gomez

Microgranules have been described with different names in keratinized and in nonkeratinized epithelium. In keratinized epithelium it seems clear that the microgranules are lamellated bodies bounded by a membrane which empty their contents into the intercellular space. Their existence in nonkeratinized epithelium is more debatable. Until now the so-called microgranules have been described in nonkeratinized bucal, lingual and cervical epithelium. In the present work we describe the morphology and nature of such structures in human vaginal epithelium.Biopsies from the midlevel of the vaginal mucosa were taken from voluntary fertile women. The specimens were divided into three groups with four vaginal specimens. The first group was obtained in the folicular phase; those of the second in the postovulatory phase and, finally, the last group corresponded to the secretory phase.


Author(s):  
Werner J. Niklowitz

After intoxication of rabbits with certain substances such as convulsant agents (3-acetylpyridine), centrally acting drugs (reserpine), or toxic metal compounds (tetraethyl lead) a significant observation by phase microscope is the loss of contrast of the hippocampal mossy fiber layer. It has been suggested that this alteration, as well as changes seen with the electron microscope in the hippocampal mossy fiber boutons, may be related to a loss of neurotransmitters. The purpose of these experiments was to apply the OsO4-zinc-iodide staining technique to the study of these structural changes since it has been suggested that OsO4-zinc-iodide stain reacts with neurotransmitters (acetylcholine, catecholamines).Domestic New Zealand rabbits (2.5 to 3 kg) were used. Hippocampal tissue was removed from normal and experimental animals treated with 3-acetylpyridine (antimetabolite of nicotinamide), reserpine (anti- hypertensive/tranquilizer), or iproniazid (antidepressant/monamine oxidase inhibitor). After fixation in glutaraldehyde hippocampal tissue was treated with OsO4-zinc-iodide stain and further processed for phase and electron microscope studies.


Author(s):  
P. Dayanandan ◽  
P. B. Kaufman

A three dimensional appreciation of the guard cell morphology coupled with ultrastjuctural studies should lead to a better understanding of their still obscure dynamics of movement. We have found the SEM of great value not only in studies of the surface details of stomata but also in resolving the structures and relationships that exist between the guard and subsidiary cells. We now report the isolation and SEM studies of guard cells from nine genera of plants.Guard cells were isolated from the following plants: Psilotum nudum, four species of Equisetum, Cycas revoluta, Ceratozamia sp., Pinus sylvestris, Ephedra cochuma, Welwitschia mirabilis, Euphorbia tirucalli and Allium cepa.


Author(s):  
T. C. Tisone ◽  
S. Lau

In a study of the properties of a Ta-Au metallization system for thin film technology application, the interdiffusion between Ta(bcc)-Au, βTa-Au and Ta2M-Au films was studied. Considered here is a discussion of the use of the transmission electron microscope(TEM) in the identification of phases formed and characterization of the film microstructures before and after annealing.The films were deposited by sputtering onto silicon wafers with 5000 Å of thermally grown oxide. The film thicknesses were 2000 Å of Ta and 2000 Å of Au. Samples for TEM observation were prepared by ultrasonically cutting 3mm disks from the wafers. The disks were first chemically etched from the silicon side using a HNO3 :HF(19:5) solution followed by ion milling to perforation of the Au side.


Sign in / Sign up

Export Citation Format

Share Document