An electron-microscope study of centrioles in differentiating motor neuroblasts

Development ◽  
1968 ◽  
Vol 20 (3) ◽  
pp. 343-354
Author(s):  
Katherine M. Lyser
Keyword(s):  
Nineteenth Century ◽  
Fine Structure ◽  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Morphological Differentiation ◽  
Nerve Cells ◽  
Electron Microscopic ◽  
Mitotic Apparatus ◽  
Mature Neurons

Mature neurons with centrioles were first described at the end of the nineteenth century and have been observed in many animals (see Cajal, 1911; Ariëns Kappers, Huber & Crosby, 1936). As mitosis rarely, if ever, occurs after morphological differentiation of the neuroblast begins, the function of the centrioles in nerve cells posed a problem which has yet to be resolved. Held (1909) described centrosomes in differentiating neuroblasts as being associated with the ‘fibrillogenous zone’, which suggests a role for the centriole in the differentiation of neurofibrils. Recently, electron-microscopic observations have refocused attention on the possibility of morphological and functional association between the centrioles of nerve cells and the fibrillar elements, especially neurotubules, which appear to be similar in fine structure to microtubules of other types of cells and to spindle tubules of the mitotic apparatus.

An Electron Microscope study of a Small Free-living Amoeba (Hartmanella astronyxis)

1959 ◽  
Vol s3-100 (49) ◽  
pp. 13-15
Author(s):  
K. DEUTSCH ◽  
M. M. SWANN
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Cell Membrane ◽  
Nuclear Membrane ◽  
Layered Structure ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Honeycomb Structure ◽  
Free Living ◽  
Free Living Amoeba

The fine structure of a species of small free-living amoeba, Hartmanella astronyxis, has been investigated. The mitochondria resemble those of other species of amoeba. Structureless bodies of about the same size as mitochondria are sometimes found in association with them. Double membranes are common in the cytoplasm, and may show granules along their outer borders. The nuclear membrane is a double-layered structure, with a honeycomb structure evident in tangential sections. The cell membrane is also double-layered, or occasionally multi-layered.

scholarly journals An Electron Microscope Study of the Source and Distribution of Ferritin in Hepatic Parenchymal Cells of the Newborn Rabbit

Blood ◽  
1960 ◽  
Vol 15 (4) ◽  
pp. 480-490 ◽  
Author(s):  
JAMES C. HAMPTON
Keyword(s):  
Electron Microscope ◽  
Microscope Study ◽  
Light Microscope ◽  
Electron Microscope Study ◽  
Hepatic Cell ◽  
Cell Cytoplasm ◽  
Electron Microscopic ◽  
Newborn Rabbit ◽  
Blue Reaction ◽  
Parenchymal Cells

Abstract Evidence that erythrocytes are phagocytized and dismantled by hepatic parenchymal cells in the newborn rabbit is presented. It is concluded that in these cells iron is recovered from disintegrating erythrocytes, synthesized into ferritin and released into the hepatic cell cytoplasm and into the biliary passages. These conclusions are based upon observations on the distribution of material giving the Prussian blue reaction in sections of liver as revealed by the light microscope and upon electron microscopic images of particles displaying the size, density and configuration of the ferritin molecule.

An electron-microscope study of the structure of Domiati cheese

1973 ◽  
Vol 40 (1) ◽  
pp. 113-117 ◽  
Author(s):  
M. H. Abd El-Salam ◽  
Safinaz El-Shibiny
Keyword(s):  
Electron Microscope ◽  
Internal Structure ◽  
Microscopic Examination ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Electron Microscopic Examination ◽  
Spherical Particles ◽  
Electron Microscopic ◽  
Ultrathin Sections ◽  
Large Spherical

SummaryA technique is described for preparing ultrathin sections from cheese for electron-microscopic examination. The internal structure of fresh Domiati cheese was found to be composed of a framework of large, spherical casein aggregates held by bridges and enclosing fat.After pickling, the casein aggregates were partly disintegrated into small spherical particles forming a loose structure.

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.

Electron microscope study on the glial filaments of astrocytes in the rat brain

1978 ◽  
Vol 36 (2) ◽  
pp. 618-619
Author(s):  
S. Mori ◽  
K. Furukawa ◽  
H. Abe
Keyword(s):  
Body Weight ◽  
Electron Microscope ◽  
Glial Cells ◽  
Microscope Study ◽  
Phosphate Buffer ◽  
Electron Microscope Study ◽  
Gold Chloride ◽  
Electron Microscopic ◽  
New Knowledge ◽  
Microscopic Studies

With the electron microscope, it was demonstrated that the glial filaments existed in astrocytes and could be impregnated by Cajal's gold chloride sublimate solution. By this conspicuous structure of glial filaments, thus, the astrocytes have long been differentiated from other glial cells from the classical light microscopic studies till the recent electron microscopic observations. Further investigations could add the new knowledge on this important component of glial cells in this laboratory that the actin- like filaments might be contained among the glial filaments. It will be shown in this report that glial filaments of astrocytes are consisted of the heterogenous groups of filaments, and some of them can bind with the heavy meromyosins (HMM).Normal rats (about 120 g body weight) were anesthetized with Nembutal and fixed by perfusion through the heart for 30 minutes with the fixative. This fluid was consisted of 3 % glutaraldehyde, 2 % paraformaldehyde, 4 % sucrose and 0. 5 mM CaCl2 in 0. 1 M phosphate buffer at PH 7. 4.

Thrombin and Reptilase Induced Fibrin Structures in the Presence of Dextran: A Quantitative Electron Microscope Study

1975 ◽  
Author(s):  
W. H. Krause ◽  
P. Zimmermann
Keyword(s):  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Microscopic Analysis ◽  
Electron Microscopic Analysis ◽  
Segment Length ◽  
Electron Microscopic ◽  
Fibrin Network ◽  
Significant Difference ◽  
Microscopic Studies

The present study describes an electron microscopic analysis, using a quantitative morphometric method, of fibrin network obtained by thrombin and reptilase in the presence of dextran. The thickness of the thrombin induced fibrin meshwork show a significant difference compared to fibrin formed by reptilase. The segment length of reptilase fibrin are reduced to 25% and the thickness of the fibers are reduced to 75% in comparison with thrombin fibrin.The thickness of the fibrin meshwork obtained by thrombin and/or reptilase in the presence of dextran ( w 40,000) is significantly diminished compared to saline controls (p < 0.001). Segment length and thickness of fibers in the clots with dextran showed different results when thrombin or reptilase were used as enzyme.The investigation indicates that the fibrin meshwork formed by thrombin and/or reptilase in the presence or absence of dextran result in a significantly different fibrin morphylogy. The results are different to the so far descriptive electron microscopic studies.

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