scholarly journals THE FINE STRUCTURE OF ASTROCYTES IN THE CEREBRAL CORTEX AND THEIR RESPONSE TO FOCAL INJURY PRODUCED BY HEAVY IONIZING PARTICLES

1965 ◽  
Vol 25 (2) ◽  
pp. 141-157 ◽  
Author(s):  
David S. Maxwell ◽  
Lawrence Kruger
Keyword(s):  
Cerebral Cortex ◽  
Fine Structure ◽  
Electron Microscope ◽  
Reactive Astrocytes ◽  
Lipid Bodies ◽  
Particle Irradiation ◽  
Fibrous Astrocytes ◽  
Primitive Forms ◽  
Focal Injury ◽  
Glycogen Particles

Normal and reactive astrocytes in the cerebral cortex of the rat have been studied with the electron microscope following focal alpha particle irradiation. The presence of glycogen and approximately 60-A fibrils identify astrocyte cytoplasm in formalin-perfused tissue. The glycogen particles facilitate the identification of small processes and subpial and perivascular end-feet. Both protoplasmic and fibrous astrocytes contain cytoplasmic fibrils and should be distinguished on the basis of the configuration of their processes and their distribution. Acutely reactive astrocytes are characterized by a marked increase in the number of glycogen granules and mitochondria from the first day after irradiation. These cells later hypertrophy and accumulate lipid bodies and increased numbers of cytoplasmic fibrils. The glial "scar" consists of a greatly expanded volume of astrocyte cytoplasm filled with fibrils and displays no signs of astrocyte death, reversion to primitive forms, or extensive multiplication.

Uredospore development in Puccinia graminis

1969 ◽  
Vol 47 (12) ◽  
pp. 2061-2064 ◽  
Author(s):  
M. A. Ehrlich ◽  
H. G. Ehrlich
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Electron Microscope ◽  
Wall Layer ◽  
Tangential Section ◽  
Puccinia Graminis ◽  
Lipid Bodies ◽  
External Wall ◽  
Additional Information ◽  
Spine Development

The present paper reports a number of electron microscope observations on the protoplasm and walls of developing spores which provide additional information on uredospore wall and spine development and on the fine structure of organelles, particularly of mitochondria and endoplasmic reticulum and of lipid bodies in developing spores. Micrographs of partially extracted uredospore walls and of chromium-shadowed extracted sections demonstrate the architecture of the wall as seen in cross and tangential section. Three distinct wall zones are clearly visible with the external wall layer forming the boundary of the germinal pore.

scholarly journals AN ELECTRON MICROSCOPIC STUDY OF THE DEVELOPMENT OF SYNAPSES IN CULTURED FETAL MOUSE CEREBRUM CONTINUOUSLY EXPOSED TO XYLOCAINE

1971 ◽  
Vol 49 (2) ◽  
pp. 362-371 ◽  
Author(s):  
Pat G. Model ◽  
Murray B. Bornstein ◽  
Stanley M. Crain ◽  
George D. Pappas
Keyword(s):  
Cerebral Cortex ◽  
Fine Structure ◽  
Electron Microscope ◽  
Impulse Activity ◽  
Morphological Differentiation ◽  
Bioelectric Activity ◽  
Electron Microscopic ◽  
Fetal Mouse ◽  
Electrical Impulse ◽  
Mouse Cerebral Cortex

Explants of fetal mouse cerebral cortex, continuously exposed to the local anesthetic Xylocaine from the time of explantation to the time of fixation, were examined in the electron microscope to determine whether morphologically normal synapses and potentially functional interneuronal synaptic networks can form in the absence of electrical impulse activity. Morphological differentiation of complex synaptic networks proceeds normally, and the drug does not alter the fine structure of the formed synapses. These observations are consonant with the electrophysiological data which show that the potential for complex bioelectric activity can develop in the absence of its expression. The development and maturation of functional synaptic networks, then, is not contingent upon prior electrical impulse activity. These data support the concept that organized neuronal assemblies are formed in forward reference to their ultimate function.

A Study on the Fine Structure of the Lateral Line Organ of the Sea Eel

1973 ◽  
Vol 31 ◽  
pp. 648-649
Author(s):  
K. Hama
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Lateral Line ◽  
Low Frequency ◽  
Sensory Cells ◽  
Apical Surface ◽  
Voltage Electron ◽  
Sensory Epithelia ◽  
Low Frequency Vibration ◽  
Transmission Electron

The lateral line organs of the sea eel consist of canal and pit organs which are different in function. The former is a low frequency vibration detector whereas the latter functions as an ion receptor as well as a mechano receptor.The fine structure of the sensory epithelia of both organs were studied by means of ordinary transmission electron microscope, high voltage electron microscope and of surface scanning electron microscope.The sensory cells of the canal organ are polarized in front-caudal direction and those of the pit organ are polarized in dorso-ventral direction. The sensory epithelia of both organs have thinner surface coats compared to the surrounding ordinary epithelial cells, which have very thick fuzzy coatings on the apical surface.

Fine Structure of Interdental Cells in the Mouse Cochlea

1970 ◽  
Vol 28 ◽  
pp. 140-141
Author(s):  
Roberta M. Bruck
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Young Adult ◽  
Uranyl Acetate ◽  
Ground Substance ◽  
Tectorial Membrane ◽  
Lead Citrate ◽  
Unusual Structure ◽  
Thin Sections ◽  
Collagenous Fibers

An unusual structure in the cochlea is the spiral limbus; this periosteal tissue consists of stellate fibroblasts and collagenous fibers embedded in a translucent ground substance. The collagenous fibers are arranged in vertical columns (the auditory teeth of Haschke). Between the auditory teeth are interdental furrows in which the interdental cells are situated. These epithelial cells supposedly secrete the tectorial membrane.The fine structure of interdental cells in the rat was reported by Iurato (1962). Since the mouse appears to be different, a description of the fine structure of mouse interdental cells' is presented. Young adult C57BL/6J mice were perfused intervascularly with 1% paraformaldehyde/ 1.25% glutaraldehyde in .1M phosphate buffer (pH7.2-7.4). Intact cochlea were decalcified in .1M EDTA by the method of Baird (1967), postosmicated, dehydrated, and embedded in Araldite. Thin sections stained with uranyl acetate and lead citrate were examined in a Phillips EM-200 electron microscope.

Fine structure of the retina of the giant scallop, Placopecten magellanicus

1984 ◽  
Vol 42 ◽  
pp. 312-313
Author(s):  
C.V.L. Powell
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Light Intensity ◽  
Scanning Electron Microscope ◽  
Eye Development ◽  
Preliminary Observation ◽  
Columnar Epithelium ◽  
Placopecten Magellanicus ◽  
Environmental Light ◽  
Scanning Electron

The overall fine structure of the eye in Placopecten is similar to that of other scallops. The optic tentacle consists of an outer columnar epithelium which is modified into a pigmented iris and a cornea (Fig. 1). This capsule encloses the cellular lens, retina, reflecting argentea and the pigmented tapetum. The retina is divided into two parts (Fig. 2). The distal retina functions in the detection of movement and the proximal retina monitors environmental light intensity. The purpose of the present study is to describe the ultrastructure of the retina as a preliminary observation on eye development. This is also the first known presentation of scanning electron microscope studies of the eye of the scallop.

Ultrastructure of primary spermatocyte in fish (Tilapia: Oreochromis niloticus): The synaptonemal complex

1986 ◽  
Vol 44 ◽  
pp. 288-289
Author(s):  
T. Guha ◽  
A. Q. Siddiqui ◽  
P. F. Prentis
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Synaptonemal Complex ◽  
Oreochromis Niloticus ◽  
Short Communication ◽  
Primary Spermatocyte ◽  
Mitotic Division ◽  
Meiotic Cell ◽  
Electron Microscope Level ◽  
Homologous Chromosomes

The Primary Spermatocytes represent a stage in spermatogenesis when the first meiotic cell division occurs. They are derived from Spermatogonium or Stem cell through mitotic division. At the zygotene phase of meiotic prophase the Synaptonemal complex appears in these cells in the space between the paired homologous chromosomes. Spermatogenesis and sperm structure in fish have been studied at the electron microscope level in a few species? However, no work has yet been reported on ultrastructure of tilapia, O. niloticus, spermatozoa and spermatogenetic process. In this short communication we are reporting the Ultrastructure of Primary Spermatocytes in tilapia, O. niloticus, and the fine structure of synaptonemal complexes seen in the spermatocyte nuclei.

Some Aspects of Exelfs Analysis in the Electron Microscope

1980 ◽  
Vol 38 ◽  
pp. 118-119
Author(s):  
D. E. Johnson ◽  
S. Csillag
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Energy Loss ◽  
Analytical Electron Microscopy ◽  
Interference Effects ◽  
Interatomic Distances ◽  
X Ray ◽  
Structure Information ◽  
Microanalytical Technique ◽  
Analytical Electron

Recently, the applications area of analytical electron microscopy has been extended to include the study of Extended Energy Loss Fine Structure (EXELFS). Modulations past an ionization edge in the energy loss spectrum (EXELFS), contain atomic fine structure information similar to Extended X-ray Absorbtion Fine Structure (EXAFS). At low momentum transfer the main contribution to these modulations comes from interference effects between the outgoing excited inner shell electron waves and electron waves backscattered from the surrounding atoms. The ability to obtain atomic fine structure information (such as interatomic distances) combined with the spatial resolution of an electron microscope is unique and makes EXELFS an important microanalytical technique.

scholarly journals DNA AND THE FINE STRUCTURE OF SYNAPTIC CHROMOSOMES IN THE DOMESTIC ROOSTER (GALLUS DOMESTICUS)

1964 ◽  
Vol 23 (1) ◽  
pp. 63-78 ◽  
Author(s):  
James R. Coleman ◽  
Montrose J. Moses
Keyword(s):  
Electron Microscopy ◽  
Heavy Metal ◽  
Fine Structure ◽  
Electron Microscope ◽  
Meiotic Prophase ◽  
Gallus Domesticus ◽  
Feulgen Staining ◽  
Synaptinemal Complex ◽  
Relationship Of ◽  
The Relationship

The indium trichloride method of Watson and Aldridge (38) for staining nucleic acids for electron microscopy was employed to study the relationship of DNA to the structure of the synaptinemal complex in meiotic prophase chromosomes of the domestic rooster. The selectivity of the method was demonstrated in untreated and DNase-digested testis material by comparing the distribution of indium staining in the electron microscope to Feulgen staining and ultraviolet absorption in thicker sections seen with the light microscope. Following staining by indium, DNA was found mainly in the microfibril component of the synaptinemal complex. When DNA was known to have been removed from aldehyde-fixed material by digestion with DNase, indium stainability was also lost. However, staining of the digested material with non-selective heavy metal techniques demonstrated the presence of material other than DNA in the microfibrils and showed that little alteration in appearance of the chromosome resulted from DNA removal. The two dense lateral axial elements of the synaptinemal complex, but not the central one to any extent, also contained DNA, together with non-DNA material.

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.

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