THE EMBRYOLOGY OF LYTTA VIRIDANA LE CONTE (COLEOPTERA: MELOIDAE): II. THE STRUCTURE OF THE VITELLINE MEMBRANE

1967 ◽  
Vol 45 (4) ◽  
pp. 497-503 ◽  
Author(s):  
R. G. Gerrity ◽  
J. G. Rempel ◽  
P. R. Sweeny ◽  
N. S. Church
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Microscope ◽  
Three Dimensional ◽  
Apparent Porosity ◽  
Vitelline Membrane ◽  
Sperm Penetration

This paper deals with the structure of the vitelline membrane of Lytta viridana as seen through the light microscope and the electron microscope. Through the light microscope, the vitelline membrane of a freshly laid egg appears to be porous. This condition persists for 15–30 min. During this time the pores become progressively smaller until the membrane becomes solid and continuous. The electron microscope reveals that the vitelline membrane of the freshly laid egg is actually composed of a three-dimensional membranous system which condenses into a homogeneous membrane after 15–30 min. The apparent porosity of the membrane as seen through the light microscope is interpreted in terms of its fine structure, and the belief is expressed that solidification of the membranous system is initiated by sperm penetration.

The Ultra-fine Structure of Lipid Globules in the Neurones of Helix aspersa

1958 ◽  
Vol s3-99 (46) ◽  
pp. 279-284
Author(s):  
J.T. Y. CHOU ◽  
G. A. MEEK
Keyword(s):  
Methylene Blue ◽  
Fine Structure ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Light Microscope ◽  
Helix Aspersa

The three kinds of lipid globules recognizable in the living neurones of Helix aspersa have been examined under the electron microscope. The globules of the kind that can be stained blue with methylene blue during life are seen in electron micrographs as spheres or spheroids, with concentric lamination, after calcium-osmium fixation. After fixation with sucrose-osmium laminated crescentic bodies are seen instead; these appear to be formed by distortion of the ‘blue’ globules. The yellow globules contain electrondense material, and sometimes appear reticular. It is possible that the yellow globules may originate by transformation of some of the ‘blue’ globules. The colourless globules generally appear as crenated objects; this appearance may be a shrinkage artifact. Apart from the mitochondria and the three kinds of lipid globules described, no other object large enough to be identified with the light microscope has been seen in the cytoplasm.

scholarly journals FINE STRUCTURE OF MEMBRANOUS AND MICROFIBRILLAR SYSTEMS IN THE CORTEX OF PARAMECIUM CAUDATUM

1971 ◽  
Vol 49 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Richard D. Allen
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Three Dimensional ◽  
Paramecium Caudatum ◽  
Fibrillar Material ◽  
Muscular Function ◽  
Branching System

An electron microscope study of the cortex of Paramecium caudatum has revealed new details pertinent to several unresolved problems. The lateral boundaries of the alveoli do not regularly follow the crests of the polygonal ridges and thus their staining with silver cannot account for the external lattice seen by light microscopists. A granulo-fibrillar material is present, however, within the peaks of the ridges, which would account for the external lattice if so stained. Perforations are present between adjacent alveoli which make the whole mosaic of alveolar sacs within the cell's cortex continuous—both the membranes and the lumen. A microfibrillar system exhibiting a cross-striated pattern lies in the superficial cortex. These bands are inserted at their ends in the epiplasm and have a fine structure and arrangement suggesting a muscular function. The infraciliary lattice is a branching system of fibers with electron-opaque posts at the center of each branching locus. This system is distinct from the striated bands in morphology and in space. The epiplasm is discontinuous along the crests of the ridges, which may account for the pellicles' disposition to tear along these lines. A three-dimensional drawing is presented to show the interrelationships between the above membranous and microfibrillar systems.

scholarly journals THE FINE STRUCTURE OF THE RAT CEREBELLUM

1964 ◽  
Vol 23 (2) ◽  
pp. 277-293 ◽  
Author(s):  
Robert M. Herndon
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Microscope ◽  
Osmium Tetroxide ◽  
Granule Cells ◽  
Cell Types ◽  
Bergmann Glia ◽  
Rat Cerebellum

This paper describes the fine structure of the granule cells, stellate neurons, astrocytes, Bergmann glia, oligodendrocytes, and microglia of the rat cerebellum after fixation by perfusion with buffered 1 per cent osmium tetroxide. Criteria are given for differentiating the various cell types, and the findings are correlated with previous light microscope and electron microscope studies of the cerebellum.

The Use of the Scanning Electron Microscope for the Examination of Sectioned Tissue

1967 ◽  
Vol 25 ◽  
pp. 254-255
Author(s):  
L.W. McDonald ◽  
R.F.W. Pease ◽  
T.L. Hayes
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Light Microscope ◽  
Secondary Electron ◽  
Three Dimensional ◽  
Paraffin Section ◽  
Intact Cells ◽  
Dimensional Image ◽  
Electron Mode ◽  
Scanning Electron

In previous studies from this laboratory the scanning electron microscope has been used to examine biological materials in the cathodo-luminescense and secondary electron modes. In these studies intact cells or even entire insects have been examined, some in the living state. Epithelial surfaces have been exposed and examined. Prior to the work to be described, no reports of the examination of tissue sections in the scanning electron microscope have been found, although sufaces of solid one millimeter cubes of tissue have been examined.In the present work blocks of solid tissue fixed in buffered aldehyde have been dehydrated in graded alcohols, embedded in paraffin, section at 4μ and examined successfully in the scanning electron microscope. These sections have been over 1 cm square and have been stained for subsequent comparative examination with the light microscope. With the scanning electron microscope in the secondary electron mode, magnifications of X5,000 have been found useful. In addition to the increased resolution as compared to the light microscope, a three dimensional image is obtained. An advantage over the conventional electron microscope is that tissue areas 1,000 times greater may be examined in the large sections without any obscuring grid bars, again with the three dimensional image. With the cathode ray display tube used, magnifications range from X30 to over X20,000

The distribution and fine structure of the integumentary papillae of the cercaria ofHimasthla secunda(Nicoll)

Parasitology ◽  
1970 ◽  
Vol 61 (2) ◽  
pp. 219-227 ◽  
Author(s):  
H. D. Chapman ◽  
R. A. Wilson
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Spatial Distribution ◽  
Fine Structure ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Silver Nitrate ◽  
Light Microscope ◽  
Transmission Electron ◽  
Scanning Electron

The distribution of the integumentary papillae of the cercaria ofHimasthla secundahas been studied by a variety of techniques. Structures stained by silver nitrate and visible under the light microscope correspond in their spatial distribution with papillae observed under the scanning electron microscope. The tegumentary papillae described with the light and scanning electron microscope are correlated with the specialized nerve endings in the tegument as seen in transmission electron microscopy. The ultrastructure of these papillae is examined by conventional transmission electron microscopy and the probability that these structures are sensory is discussed.

The fine structure of the body wall of Polymorphus minutus (Goeze, 1782) (Acanthocephala)

Parasitology ◽  
1965 ◽  
Vol 55 (2) ◽  
pp. 357-364 ◽  
Author(s):  
D. W. T. Crompton ◽  
D. L. Lee
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Microscope ◽  
Body Wall ◽  
Technical Assistance ◽  
The Body ◽  
Parasitic Nematodes ◽  
Surface Layers ◽  
Longitudinal Muscles

The body wall of Polymorphus minutus has been studied with the electron microscope and the structure of the various layers has been described.The layers are the same in number as those seen with the light microscope, and pores have been found which penetrate the cuticle. Thus, the structure of the surface layers is such as would facilitate the absorption of nutrients.It has been found that the cuticle and striped layer extend over the trunk spines, a feature which increases the area of the absorptive surface of the parasite.The structure of the striped layer of the praesoma supports the theory that the praesoma body wall and lemnisci are involved in the absorption of fat.Mitochondria have been detected in the felt and radial layers of the body wall and in the circular and longitudinal muscles.The body wall of this acanthocephalan worm is entirely different from the body wall of trematodes, cestodes and parasitic nematodes.We are grateful to Dr P. Tate for helpful discussions, Dr R. J. Skaer for criticism of the manuscript and to Professor J. D. Boyd for permission to use the electron microscope in the Department of Anatomy. Thanks are also due to Mr A. J. Page for technical assistance.

Considerations in Making Stereo Micrographs With the Scanning Electron Microscope

1973 ◽  
Vol 31 ◽  
pp. 234-235
Author(s):  
E. R. Walter
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Three Dimensional ◽  
Spatial Relationships ◽  
Additional Information ◽  
Electron Microscopes ◽  
Scanning Electron Microscopes ◽  
Scanning Electron

The information obtainable with the scanning electron microscope can often be increased severalfold through the use of stereomicrograph pairs. Not only is the detail which can be observed the equivalent of a 2X increase in magnification over that apparent in a single micrograph, but, threedimensional spatial relationships are more accurately preserved. This is especially true where protruding or pyramided fine structure and/or gross reentrance exists. Since stereo micrographs are conveniently obtained with most scanning electron microscopes, it is generally desirable to add the additional information they offer whenever the three-dimensional relationships present in the specimen'are not readily apparent.

The Fine Structure of the Membranes which Cover the Egg of the Grasshopper, Melanoplus Differentialis, with Special Reference to the Hydropyle

1963 ◽  
Vol s3-104 (67) ◽  
pp. 321-334
Author(s):  
ELEANOR H. SLIFER ◽  
SANT S. SEKHON
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Special Reference ◽  
Outer Surface ◽  
Vitelline Membrane ◽  
Homogeneous Layer ◽  
Dense Layer ◽  
Melanoplus Differentialis ◽  
Pore Canals

Electron-microscope studies have shown that the epicuticle of the hydropyle consists of 2 layers. The inner is complexly folded and the outer consists of a meshwork of fine fibrils which fills the spaces between the folds. The endocuticle is laminated, penetrated by pore canals, and contains many wax-canal filaments. The filaments are especially abundant immediately before diapause. During diapause a dense, homogeneous layer is present at the outer surface of the hydropyle. It is absent before diapause and discontinuous or absent in eggs which are developing without diapause, or after diapause has been prevented or broken. The results confirm the conclusions, based on earlier studies, that the hydropyle is waterproofed by a waxy coating during diapause and that this material is absent or discontinuous in eggs which are developing. The vitelline membrane is an excessively thin, dense layer which lies below the chorion and lines the micropyles. It is less resistant at the posterior end of the egg than elsewhere. During development it is incorporated into the cuticle, which is secreted by the serosa. It is now believed that the ‘resistant endochorion’ described earlier for this species is identical with the vitelline membrane which Salt described in 1952 for the eggs of Melanoplus bivittatus.

The fine structure of the trunk and praesoma wall of Acanthocephalus ranae (Schrank, 1788), Lühe, 1911

Parasitology ◽  
1967 ◽  
Vol 57 (3) ◽  
pp. 475-486 ◽  
Author(s):  
R. A. Hammond
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Electron Microscope ◽  
Light Microscope ◽  
Body Wall ◽  
Technical Assistance ◽  
The Body ◽  
The Other ◽  
Fat Excretion ◽  
Research Grant

The wall of the trunk, that of the praesoma, and the lemnisci of Acanthocephalus ranae have been studied by electron microscopy. Striations visible in sections of the body wall under the light microscope do not correspond with the ‘striped layer’ revealed by the electron microscope.A new region, the ‘canal layer’, has been described. This contains canals running into the body wall from cuticular pores.Structurally the wall of the trunk and that of the praesoma are similar. The lemnisci resemble the ‘inner layer’ of the praesoma wall. However, it is suggested that the wall of the trunk differs physiologically from that of the praesoma, and from the lemnisci. The possible roles of the wall of the praesoma and the lemnisci in fat excretion or uptake have been discussed.The body wall of A. ranae has been compared with that of the other acantho-cephalans studied with the electron microscope.Grateful acknowledgement is made to D.S.I.R. (now S.R.C.) for a research grant to the Department of Zoology for the purchase of a Huxley ultramicrotome, a vacuum coating unit, and an AEI EM 6 electron microscope.I am grateful to Dr D. A. Erasmus for reading and criticizing the manuscript, and to Mr T. Davies for valuable technical assistance.

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