scholarly journals Intercellular Attachment in the Epithelium of Hydra As Revealed by Electron Microscopy

1959 ◽  
Vol 6 (3) ◽  
pp. 343-352 ◽  
Author(s):  
R. L. Wood
Keyword(s):  
Electron Microscopy ◽  
Intercellular Space ◽  
Epoxy Resins ◽  
Phosphotungstic Acid ◽  
Internal Environment ◽  
Prominent Feature ◽  
Cell Surfaces ◽  
Intercellular Spaces ◽  
Two Peaks ◽  
Plasma Unit

In Hydra adjacent epithelial cells are bound firmly to each other by desmosomes of a type not described in detail hitherto. The most prominent feature of these desmosomes is the presence of a series of parallel lamellae which bridge the intercellular space and connect the two apposed cell surfaces directly. These structures, here termed intercellular attachment lamellae, display two peaks of density about 50 A apart. These dense lines appear in some instances to be continuous with the outer dense components of the plasma unit membranes of the attached cells. The presence of prominent lamellae in intercellular attachments is sufficiently distinctive to deserve special terminology; accordingly, the term septate desmosome is proposed. It is noted that septate desmosomes may have been seen in other animals in instances where published electron micrographs show cross-striations or prominent connections in regions of intercellular attachment. It is suggested that septate desmosomes in Hydra, in addition to binding cells firmly to each other, form barriers to the movement of water into intercellular spaces and thus help to protect the organism's internal environment. Observations on the use of phosphotungstic acid for improving contrast in materials embedded in epoxy resins are also recorded.

scholarly journals MEMBRANE-COATING GRANULES OF KERATINIZING EPITHELIA

1965 ◽  
Vol 24 (2) ◽  
pp. 297-307 ◽  
Author(s):  
A. Gedeon Matoltsy ◽  
Paul F. Parakkal
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Epithelial Cells ◽  
Cell Envelope ◽  
Cell Periphery ◽  
Cell Surfaces ◽  
Intercellular Spaces ◽  
Cytoplasmic Granules ◽  
Coated Cell ◽  
Membrane Coating

The purpose of this study has been to obtain information on the development of the envelop of horny cells that resists the action of keratinolytic agents. Toward this end the epidermis, oral mucosa, and tongue epithelium of various vertebrates, as well as the isolated envelopes of horny cells, were examined by electron microscopy. It was found that small cytoplasmic granules (1,000 to 5,000 A) that develop within differentiating epithelial cells move toward the cell periphery, and after fusion with the plasma membrane, empty their contents into the intercellular spaces. The content of the granules spreads over the cell surfaces, and subsequently a thickened and coated cell envelope is formed that resists the action of keratinolytic agent. The membrane-coating granule is regarded as a specific differentiation product of the keratinizing epithelium. It contains numerous inner membranes and is assumed to engage in synthetic activities such as, perhaps, the formation of polysaccharides.

A Unique Cell Contact in the Adrenal Cortex

1971 ◽  
Vol 29 ◽  
pp. 504-505
Author(s):  
Daniel S. Friend
Keyword(s):  
Intercellular Space ◽  
Plasma Membranes ◽  
Phosphotungstic Acid ◽  
Cell Contact ◽  
Zona Fasciculata ◽  
Adrenocorticotrophic Hormone ◽  
Cell Surfaces ◽  
Cortical Cells ◽  
Unique Cell ◽  
Lateral Cell

A unique periodic structure exists between cortical cells in all zones of the mature rat, guinea pig, and human adrenal gland. This singular zonule is most highly developed between the lateral cell surfaces and between the basilar, perisinusoidal, interdigitating microvilli in the zona fasciculata and occasionally occurs between microvilli of the same cell. In the rat, its fine structure is not appreciably altered by hypophysectomy or adrenocorticotrophic hormone stimulation.In views which crisply reveal the unit membrane architecture of the smoothly parallel plasma membranes, the 250-350-Å intercellular space is bisected by a series of circles 80-150 Å in diameter varying widely in center-to-center spacing (160-400 Å). This area of contact resembles the zonula continua in its appearance after aldehyde, OsO4, and aldehyde-OsO4-phosphotungstic acid fixation and in its facile digestibility by protease in Epon sections.

Fine structure of the lumbosacral neural folds in the mouse embryo

Development ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 279-290
Author(s):  
Doris B. Wilson ◽  
Laurel A. Finta
Keyword(s):  
Electron Microscopy ◽  
Mouse Embryo ◽  
Intercellular Space ◽  
Intercellular Spaces ◽  
Lumbosacral Region ◽  
Transmission Electron ◽  
Junctional Complexes ◽  
Pass Through ◽  
Means Of Transmission ◽  
Gap Junctional

The neural folds in the lumbosacral region of the normal 8-day and 9-day mouse embryo were studied by means of transmission electron microscopy with and without lanthanum treatment. The cells showed an abundance of ribosomes, microtubules arranged parallel to the long axes of the cells, and microfilaments extending across the apices. At the luminal border junctional complexes were common, and an occasional midbody was seen stretching between adjacent cells nearing the end of telophase. In the 8-day embryos, gap junctional vesicles (annular nexuses) bounded by layered membranes and containing cytoplasm with ribosome-like material were commonly observed; at 9 days the vesicles were relatively rare. The lanthanum-treated material demonstrated that the tracer was able to pass through the subluminal junctional complexes and throughout the intercellular spaces. However, the space between the membranes of the gap junctional vesicles lacked lanthanum and thus apparently did not communicate with the intercellular space.

Electron microscopy of endocardial cell populations

1978 ◽  
Vol 36 (2) ◽  
pp. 486-487
Author(s):  
T. G. Sarphie ◽  
C. R. Comer ◽  
D. J. Allen
Keyword(s):  
Electron Microscopy ◽  
Plasma Membrane ◽  
Cellular Transformation ◽  
Cell Populations ◽  
Cell Surfaces ◽  
Kb Cells ◽  
Dna Viruses ◽  
Cell Cycles ◽  
Ultrastructural Studies ◽  
Endocardial Cell

Previous ultrastructural studies have characterized surface morphology during norma cell cycles in an attempt to associate specific changes with specific metabolic processes occurring within the cell. It is now known that during the synthetic ("S") stage of the cycle, when DNA and other nuclear components are synthesized, a cel undergoes a doubling in volume that is accompanied by an increase in surface area whereby its plasma membrane is elaborated into a variety of processes originally referred to as microvilli. In addition, changes in the normal distribution of glycoproteins and polysaccharides derived from cell surfaces have been reported as depreciating after cellular transformation by RNA or DNA viruses and have been associated with the state of growth, irregardless of the rate of proliferation. More specifically, examination of the surface carbohydrate content of synchronous KB cells were shown to be markedly reduced as the cell population approached division Comparison of hamster kidney fibroblasts inhibited by vinblastin sulfate while in metaphase with those not in metaphase demonstrated an appreciable decrease in surface carbohydrate in the former.

Effect of ADH on Rat Renal Papilla, an Ultrastructural and Cytochemical Study

1973 ◽  
Vol 31 ◽  
pp. 410-411
Author(s):  
C. N. Sun ◽  
H. J. White ◽  
E. J. Towbin
Keyword(s):  
Electron Microscopy ◽  
Diabetes Insipidus ◽  
Renal Papilla ◽  
Milk Diet ◽  
Intercellular Spaces ◽  
Cytochemical Study ◽  
Collecting Tubule ◽  
Concentrate Urine ◽  
Staining Techniques ◽  
Collecting Tubules

Diabetes insipidus and compulsive water drinking are representative of two categories of antidiuretic hormone (ADH) lack. We studied a strain of rats with congenital diabetes insipidus homozygote (DI) and normal rats on an isocaloric fortified dilute milk diet. In both cases, the collecting tubules could not concentrate urine. Special staining techniques, Alcian Blue-PAS for light microscopy and lanthanum nitrate for electron microscopy were used to demonstrate the changes in interstitial mucopolysaccharides (MPS). The lanthanum staining was done according to the method of Khan and Overton.Electron microscopy shows cytoplasmic lesions, vacules, swelling and degenerating mitochondria and intercellular spaces (IS) in the collecting tubule cells in DI and rats on milk diet.

The Morphology of Vacuolated Cells in the Liver Following Administration of Vitamin A.

1973 ◽  
Vol 31 ◽  
pp. 408-409
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Electron Microscopy ◽  
Body Weight ◽  
Vitamin A ◽  
Light And Electron Microscopy ◽  
Liver Cells ◽  
Prominent Feature ◽  
Vascular Space ◽  
Vacuolated Cell ◽  
Vacuolated Cells ◽  
Vacuolated Cytoplasm

Vacuolated cells in the liver of young rats were studied by light and electron microscopy following the administration of vitamin A (200 units per gram of body weight). Their characteristics were compared with similar cells found in untreated animals.In rats given vitamin A, cells with vacuolated cytoplasm were a prominent feature. These cells were found mostly in a perisinusoidal location, although some appeared to be in between liver cells (Fig. 1). Electron microscopy confirmed their location in Disse's space adjacent to the sinusoid and in recesses between liver cells. Some appeared to be bordering the lumen of the sinusoid, but careful observation usually revealed a tenuous endothelial process separating the vacuolated cell from the vascular space. In appropriate sections, fenestrations in the thin endothelial processes were noted (Fig. 2, arrow).

Preservation of Plant Cell Surfaces For Scanning Electron Microscopy

1973 ◽  
Vol 31 ◽  
pp. 472-473
Author(s):  
Linda M. Sicko ◽  
Thomas E. Jensen
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Critical Point ◽  
Filter Paper ◽  
Freeze Drying ◽  
Cell Surfaces ◽  
Air Drying ◽  
Popular Method ◽  
Critical Point Drying ◽  
Scanning Electron

The use of critical point drying is rapidly becoming a popular method of preparing biological samples for scanning electron microscopy. The procedure is rapid, and produces consistent results with a variety of samples. The preservation of surface details is much greater than that of air drying, and the procedure is less complicated than that of freeze drying. This paper will present results comparing conventional air-drying of plant specimens to critical point drying, both of fixed and unfixed material. The preservation of delicate structures which are easily damaged in processing and the use of filter paper as a vehicle for drying will be discussed.

Comparison of Choriocarcinoma and Normal Placenta

1971 ◽  
Vol 29 ◽  
pp. 324-325
Author(s):  
John C. Garancis ◽  
Roland A. Pattillo ◽  
Robert O. Hussa ◽  
Jon V. Straumfjord
Keyword(s):  
Cell Lines ◽  
Small Cells ◽  
Tissue Cultures ◽  
Glycogen Depletion ◽  
Cell Surfaces ◽  
Intercellular Spaces ◽  
Concomitant Increase ◽  
Gestational Choriocarcinoma ◽  
Cytoplasmic Glycogen ◽  
Normal Placenta

Two different cell lines (Be-Wo and Jar) of human gestational choriocarcinoma have been maintained in continuous tissue culture for a period of four and two years respectively without losing the ability to elaborate human chorionic gonadotropin (HCG). Tissue cultures, as revealed by electron microscopy, consisted of small cells with single nuclei. In some instances cell surfaces were provided with microvilli but more often the intercellular spaces were narrow and bridged by desmosomes. However, syncytium was not formed. Endoplasmic reticulum (ER) was poorly developed in both cell lines, except in some Be-Wo cells it was prominent. Golgi complex, lysosomes and numerous free ribosomes, as well as excessive cytoplasmic glycogen, were present in all cells (Fig. 1). Glycogen depletion and concomitant increase of ER were observed in many cells following a single dose of 10 ugm/ml of adrenalin added to medium (Fig. 2).

Epoxy Resin Embedment

1968 ◽  
Vol 26 ◽  
pp. 100-101
Author(s):  
J. G. Adams ◽  
M. M. Campbell ◽  
H. Thomas ◽  
J. J. Ghldonl
Keyword(s):  
Electron Microscopy ◽  
Electron Beam ◽  
Epoxy Resin ◽  
Light Microscope ◽  
Epoxy Resins ◽  
Image Contrast ◽  
Tissue Preservation ◽  
Resin System ◽  
Excellent Quality

Since the introduction of epoxy resins as embedding material for electron microscopy, the list of new formulations and variations of widely accepted mixtures has grown rapidly. Described here is a resin system utilizing Maraglas 655, Dow D.E.R. 732, DDSA, and BDMA, which is a variation of the mixtures of Lockwood and Erlandson. In the development of the mixture, the Maraglas and the Dow resins were tested in 3 different volumetric proportions, 6:4, 7:3, and 8:2. Cutting qualities and characteristics of stability in the electron beam and image contrast were evaluated for these epoxy mixtures with anhydride (DDSA) to epoxy ratios of 0.4, 0.55, and 0.7. Each mixture was polymerized overnight at 60°C with 2% and 3% BDMA.Although the differences among the test resins were slight in terms of cutting ease, general tissue preservation, and stability in the beam, the 7:3 Maraglas to D.E.R. 732 ratio at an anhydride to epoxy ratio of 0.55 polymerized with 3% BDMA proved to be most consistent. The resulting plastic is relatively hard and somewhat brittle which necessitates trimming and facing the block slowly and cautiously to avoid chipping. Sections up to about 2 microns in thickness can be cut and stained with any of several light microscope stains and excellent quality light photomicrographs can be taken of such sections (Fig. 1).

Stain contamination and embedding in electron microscopy

1986 ◽  
Vol 44 ◽  
pp. 50-53
Author(s):  
Hilton H. Mollenhauer
Keyword(s):  
Electron Microscopy ◽  
Information Retrieval ◽  
Epoxy Resins ◽  
Image Contrast ◽  
Sample Preservation ◽  
Factors Associated ◽  
Amount Of Information ◽  
Electron Microscopical ◽  
Contrast Information

Many factors (e.g., resolution of microscope, type of tissue, and preparation of sample) affect electron microscopical images and alter the amount of information that can be retrieved from a specimen. Of interest in this report are those factors associated with the evaluation of epoxy embedded tissues. In this context, informational retrieval is dependant, in part, on the ability to “see” sample detail (e.g., contrast) and, in part, on tue quality of sample preservation. Two aspects of this problem will be discussed: 1) epoxy resins and their effect on image contrast, information retrieval, and sample preservation; and 2) the interaction between some stains commonly used for enhancing contrast and information retrieval.

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