scholarly journals AN ELECTRON MICROSCOPIC CHARACTERIZATION OF CLASSES OF SYNAPTIC VESICLES BY MEANS OF CONTROLLED ALDEHYDE FIXATION

1970 ◽  
Vol 44 (1) ◽  
pp. 115-124 ◽  
Author(s):  
David Bodian
Keyword(s):  
Spinal Cord ◽  
Synaptic Vesicles ◽  
Osmium Tetroxide ◽  
Sodium Cacodylate ◽  
Electron Microscopic ◽  
Osmium Tetroxide Solution ◽  
Aldehyde Fixation ◽  
Cacodylate Buffer ◽  
Peripheral Axon

Examination of variables of aldehyde fixation that may affect the shape of agranular synaptic vesicles has revealed that even brief storage of aldehyde-perfused nervous tissue pieces in cacodylate buffer, prior to hardening in osmium tetroxide, has an unusually severe flattening effect on agranular vesicles of a particular type. These are the vesicles of peripheral cholinergic axon endings, and of certain central synaptic bulbs. Types of synaptic bulbs can now be further defined on the basis of shape of agranular synaptic vesicles under controlled conditions of aldehyde fixation. Previously described "S" bulbs in the spinal cord contain uniformly spheroid vesicles, which are wholly resistant to flattening. Previously described "F" bulbs contain somewhat smaller agranular vesicles that are flattened after aldehyde fixation, even when this is followed by prompt hardening in osmium tetroxide solution. A third type, previously characterized as having irregularly round agranular vesicles after the above treatment, contains only severely flattened vesicles when the osmium tetroxide hardening is preceded by even a brief wash with sodium cacodylate buffer containing sucrose. Moreover, the "third" type is characteristic of all cholinergic peripheral axon endings examined, as well as the large axosomatic ("L") synaptic bulbs of the spinal cord.

Oligodendrocytes in Developing Hameter Cerebral Cortex

1976 ◽  
Vol 34 ◽  
pp. 126-127
Author(s):  
MB. Tank Buschmann
Keyword(s):  
Cerebral Cortex ◽  
Optic Nerve ◽  
Frontal Cortex ◽  
Osmium Tetroxide ◽  
Sodium Cacodylate Buffer ◽  
Sodium Cacodylate ◽  
Tissue Samples ◽  
Cacodylate Buffer ◽  
Layer V ◽  
Adult Hamster

Development of oligodendrocytes in rat corpus callosum was described as a sequential change in cytoplasmic density which progressed from light to medium to dark (1). In rat optic nerve, changes in cytoplasmic density were not observed, but significant changes in morphology occurred just prior to and during myelination (2). In our study, the ultrastructural development of oligodendrocytes was studied in newborn, 5-, 10-, 15-, 20-day and adult frontal cortex of the golden hamster (Mesocricetus auratus).Young and adult hamster brains were perfused with paraformaldehyde-glutaraldehyde in sodium cacodylate buffer at pH 7.3 according to the method of Peters (3). Tissue samples of layer V of the frontal cortex were post-fixed in 2% osmium tetroxide, dehydrated in acetone and embedded in Epon-Araldite resin.

Opening images of synaptic vesicles and calcium localization by means of microwave fixation method

1990 ◽  
Vol 48 (2) ◽  
pp. 182-183
Author(s):  
Vinci Mizuhira ◽  
Hiroshi Hasegawa
Keyword(s):  
Synaptic Vesicles ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Sampling Procedure ◽  
Fixation Method ◽  
Potassium Oxalate ◽  
X Ray ◽  
Cacodylate Buffer ◽  
Ultrathin Sections ◽  
Microwave Fixation

Microwave irradiation (MWI) was applied to 0.3 to 1 cm3 blocks of rat central nervous system at 2.45 GHz/500W for about 20 sec in a fixative, at room temperature. Fixative composed of 2% paraformaldehyde, 0.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.4, also contained 2 mM of CaCl2 , 1 mM of MgCl2, and 0.1% of tannic acid for conventional observation; and fuether 30-90 mM of potassium oxalate containing fixative was applied for the detection of calcium ion localization in cells. Tissue blocks were left in the same fixative for 30 to 180 min after MWI at room temperature, then proceeded to the sampling procedure, after postfixed with osmium tetroxide, embedded in Epon. Ultrathin sections were double stained with an useal manner. Oxalate treated sections were devided in two, stained and unstained one. The later oxalate treated unstained sections were analyzed with electron probe X-ray microanalyzer, the EDAX-PU-9800, at 40 KV accelerating voltage for 100 to 200 sec with point or selected area analyzing methods.

TEM comparison of osmium vs osmium with potassium ferricyanide secondary fixatives and the impact of secondary fixative temperature on tissue preservation/contrast quality

1996 ◽  
Vol 54 ◽  
pp. 910-911
Author(s):  
J. W. Horn ◽  
B. J. Dovey-Hartman ◽  
V. P. Meador
Keyword(s):  
Osmium Tetroxide ◽  
Potassium Ferricyanide ◽  
Electron Microscopic ◽  
Transmission Electron ◽  
Microscopic Evaluation ◽  
Cacodylate Buffer ◽  
Transmission Electron Microscopic ◽  
Glutaraldehyde Solution ◽  
Temperature Impact ◽  
The Impact

Osmium tetroxide (OsO4) is a universally used secondary fixative for routine transmission electron microscopic evaluation of biological specimens. Use of OsO4 results in good ultrastructural preservation and electron density but several factors, such as concentration, length of exposure, and temperature, impact overall results. Potassium ferricyanide, an additive used primarily in combination with OsO4, has mainly been used to enhance the contrast of lipids, glycogen, cell membranes, and membranous organelles. The purpose of this project was to compare the secondary fixative solutions, OsO4 vs. OsO4 with potassium ferricyanide, and secondary fixative temperature for determining which combination gives optimal ultrastructural fixation and enhanced organelle staining/contrast.Fresh rat liver samples were diced to ∼1 mm3 blocks, placed into porous processing capsules/baskets, preserved in buffered 2% formaldehyde/2.5% glutaraldehyde solution, and rinsed with 0.12 M cacodylate buffer (pH 7.2). Tissue processing capsules were separated (3 capsules/secondary fixative.solution) and secondarily fixed (table) for 90 minutes. Tissues were buffer rinsed, dehydrated with ascending concentrations of ethanol solutions, infiltrated, and embedded in epoxy resin.

Development of iron granules in honey bee oenocytes

1984 ◽  
Vol 42 ◽  
pp. 744-745
Author(s):  
Deborah A. Kuterbach
Keyword(s):  
Honey Bee ◽  
Honey Bees ◽  
Osmium Tetroxide ◽  
Developmental Stages ◽  
Iron Particles ◽  
Sodium Cacodylate ◽  
Ultrastructural Examination ◽  
Brood Comb ◽  
Cacodylate Buffer ◽  
Rich Material

Foraging honey bees are believed to use the earth's magnetic field, among other cues, in order to home. It has been reported that the abdomen of the honey bee contains magnetite and iron particles have been localized within abdominal oenocytes. Light microscopic investigations reveal that morphologically detectable iron granules are present only in adult animals older than six days after eclosion (emergence from the comb). This is a report of an ultrastructural examination of the oenocytes during the development of the worker honey bee (Apis mellifera) with particular emphasis on the time of appearance, number, and size of iron granules within the cells.Specimens of the different developmental stages were removed from brood comb, fixed in 2.5% glutaraldehyde in 5mM sodium cacodylate buffer pH 7.3, washed, and post-fixed with 1% osmium tetroxide. In order to preserve the lipid-rich material, rapid dehydration was accomplished by three changes of 50% acetone and two changes of 100% acetone before embedding in Polybed 812 epoxy resin.

Bacterioids in the Rectal Organ of the Lantern Dug Pyrops Candelaria Linn (Homoptera: Fulgoridae)

1996 ◽  
Vol 54 ◽  
pp. 806-807
Author(s):  
W.W.K. Cheung ◽  
J.B. Wang
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Sodium Cacodylate Buffer ◽  
Lead Citrate ◽  
Sodium Cacodylate ◽  
Special Pair ◽  
Adult Females ◽  
Cacodylate Buffer

The lantern bug harbours three symbionts, namely a, x and i in its body. These microorganisms are supposed to be transmitted transovarially to the future progeny. The x-symbionts are found in a special pair of organs called the x-organ which bulges to form a rectal organ in adult females. The purpose of this study is to investigate into the fine structure of the x-symbionts. This will serve as a basis for understanding the interactions of this microorganism with its host.The rectum of the lantern bug Pyrops candelaria Linn, was dissected out in buffered insect saline and fixed in 2.5% glutaradehyde in 0.1M sodium cacodylate buffer (pH 7.2) for 1 hr. The rectal organ was subsequently post-fixed in 1% osmium tetroxide (pH 7.2) and dehydrated in alcohol/acetone series. These were blocked in Spurr resin and cut with a Reichert Ultratome. Sections were stained with uranyl acetate and lead citrate and examined with a JEOL JEM-1200EX electron microscope. Thick sections (1 μn) were stained with 1% toluidine blue and examined under a Nikon Optiphot light microscope.

Are there structural alterations in synapses related to functioning?

1968 ◽  
Vol 171 (1024) ◽  
pp. 319-323 ◽  
Keyword(s):  
Visual System ◽  
Random Sampling ◽  
Synaptic Vesicles ◽  
Osmium Tetroxide ◽  
Considerable Increase ◽  
Structural Alterations ◽  
Axon Terminals ◽  
Osmium Tetroxide Solution ◽  
Synaptic Process ◽  
Exposed Animal

One would like to know whether synapses change structurally during learning or as a result of increased use, or disuse. The difficulties lie in deciding where learning takes place, how to produce a considerable increase in the amount of learning, or of use, or disuse, and how to produce such a change uniformly throughout a piece of tissue which can be examined anatomically. In recent years it has been found that exposure of light-reared animals to darkness, or of dark-reared animals to light, has effect on the cellular structure of the visual system that can be measured by light microscopy (see review by Riesen 1966). I have tried to extend this work by looking at synapses in the visual system with electron microscopy. This technique allows one to estimate the area of the synaptic profiles, to calculate the density of the axon terminals in the tissue, to measure the length of thickened apposition with the post-synaptic process and to look at the density and size of the synaptic vesicles within the synaptic profiles. Local variations in these parameters necessitate random sampling of the tissue, and this is provided by examination of several small blocks obtained by chopping the formalin-perfused tissue in osmium tetroxide solution. At all stages of the preparation from the living animal to the measurement of synapses it is essential to maintain strict pairing and identical treatment of the tissues to be compared. Sections from the light- and dark-exposed animals were mounted on opposite sides of finder grids, and batches of six plates were made from each kind of tissue alternately. The material was photographed and measured without knowing at the time whether it came from a light- or a dark-exposed animal.

Morphological Characteristics of the Abdominal Paraganglia (Extraadrenal Chromaffin Tissue) in the Rhesus Monkey

1977 ◽  
Vol 35 ◽  
pp. 642-643
Author(s):  
J.A. Mascorro ◽  
P.M. Klara ◽  
R.D. Yates
Keyword(s):  
Electron Microscopy ◽  
Rhesus Monkeys ◽  
Potassium Dichromate ◽  
Morphological Characteristics ◽  
Sodium Cacodylate Buffer ◽  
Sodium Cacodylate ◽  
Electron Microscopic ◽  
Dense Granules ◽  
Cacodylate Buffer ◽  
Chromaffin Tissue

The abdominal paraganglia represent extraadrenal chromaffin organs rich in catecholamines. Earlier work indicated that the organs degenerate soon after birth. More recently, however, investigators have reported the distribution and persistence of this extraadrenal chromaffin system in higher mammals, including man . The present work reports the occurrence of paraganglia in Rhesus monkeys and illustrates their ultrastruotural morphology.Two young adult Rhesus monkeys weighting approximately 6 kg. were anesthetized with Nembutal and perfused routinely with glutaraldehyde/ paraformaldehyde in 0.1M sodium cacodylate buffer. The paraganglia were stained and localized by immersing the retroperitoneal tissue block in glutaraldehyde/potassium diahromate and subsequently processed for electron microscopy via rapid dehydration and embedding.Potassium dichromate tracing produced a gross chromaffin reaction that initially identified the paraganglia as catecholamine containing organs. Correlative electron microscopic observations revealed that the organs were characterized by groups of cells whose cytoplasm contained conspicuous and voluminous accumulations of dense granules.

Fine Structure of Laser Induced Lesions of Rhesus Monkey Retina

1977 ◽  
Vol 35 ◽  
pp. 628-629
Author(s):  
Robert V. Blystone ◽  
William H. Bowie
Keyword(s):  
Rhesus Monkey ◽  
Osmium Tetroxide ◽  
Laser Pulses ◽  
Post Treatment ◽  
Pulse Power ◽  
Sodium Cacodylate ◽  
Train Duration ◽  
Adjacent Marker ◽  
Cacodylate Buffer ◽  
Visible Laser

The retinas of a rhesus monkey were exposed to mode-locked visible laser pulses operated under the following exposure conditions: pulse train duration, lOmsecj pulse width, ∽250 psec; pulse repetition rate,∽104 mHz; wavelength, 514.5 nm. Two threshold levels were determined on the basis of ophthalmoscopically observed lesions at one hour post treatment and at 24 hours post treatment. One hour lesion threshold was∽430 mW peak pulse power and 24 hour lesion threshold was ∽210 mW peak pulse power. A grid of 16 exposures ranging from 282 to 1587 mW were placed in the macula region of the retina with adjacent marker lesions used for co-ordinate calibration. After six months post treatment, the animal was sacrificed and perfused with 3% glutaraldehyde in 0.1 M sodium cacodylate buffer. The eyes were post fixed in buffered 1% osmium tetroxide, dehydrated and embedded in Spurr plastic.

Application of Polyethylene Glycol (PEG) Embedding and Rotary-Replication Techniques to the Study of Photoreceptor Synaptic Ribbon Ultrastructure

1988 ◽  
Vol 46 ◽  
pp. 268-269
Author(s):  
D. Howard Dickson ◽  
Stephan C. WhitefieLd ◽  
Christine A. Morrison
Keyword(s):  
Synaptic Vesicles ◽  
Freeze Substitution ◽  
Major Advance ◽  
Ice Crystal ◽  
Synaptic Ribbon ◽  
Sodium Cacodylate ◽  
Embedding Technique ◽  
Intimate Association ◽  
Cacodylate Buffer ◽  
The Cost

Synaptic ribbons (SRs) are electron-dense, LameLLar specializations found in the retina, inner ear and pineal. Although it has been suggested that SRs may have a functional role in the maintenance of synaptic terminal shape or in orienting synaptic vesicles to the presynaptic membrane neither hes been confirmed. Their intimate association with synaptic vesicles has however supported the Latter hypothesis. Controversy also exists with respect to diurnal rhythmicity of these organelles. Recently, a major advance in our knowledge of SR structure was achieved through the application of freeze-slamming and freeze-substitution techniques. However, the cost and complexity of these techniques, together with the Limitations imposed by freezing rate and ice-crystal damage has Led us to explore the use of the PEG-embedding technique to further our study of SRs in retina and pineal.Chick retinas were prepared following the technique of Kondo. Tissues were fixed in 2.5% glutaraldehyde in 0.1 M sodium cacodylate buffer containing 0.5% tannic acid at pH 7.4 for 2 hr, washed in buffer and postfixed in 1% OsO4 for 1 hr.

Site of hemocyanin synthesis in the terrestrial isopod, Armadillidiom vulgare

1989 ◽  
Vol 47 ◽  
pp. 970-971
Author(s):  
L. Faso ◽  
E. Rappa ◽  
G. Vernon ◽  
R. Witkus
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Blood Cells ◽  
Osmium Tetroxide ◽  
Oxygen Binding ◽  
Sodium Cacodylate Buffer ◽  
Sodium Cacodylate ◽  
Astacus Astacus ◽  
Transmission Electron ◽  
Cacodylate Buffer

Although hemocyanin, an oxygen binding protein, is found freely dissolved in the hemolymph of isopods its site of synthesis is still unknown.Circulating blood cel Is such as granular hemocytes have been implicated in hemocyanin synthesis in a number of arthropods including Astacus astacus and Homarus vulgaris. Circulating blood cells of Armadillidium vulgare were examined using a transmission electron microscope (TEM) for evidence of hemocyanin synthesis.For each experiment hemolymph was collected from twenty adult A. vulgare and fixed for 1 hour in 200 uL of 3.5% glutaraldehyde in 0.1M sodium cacodylate buffer pH 7.4 with 0.05% calcium chloride added. Hemolymph was then centrifuged at 3000 rpm in an IEC-DPR-6000 centrifuge for 15 minutes at 15 degrees centigrade. The supernatant was removed, and the resulting pellet was washed with three changes of sodium cacodylate buffer. Postfixation of the pellet was done in 1% osmium tetroxide for 1 hour.

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