scholarly journals Fine Structures of Cell Envelopes of Chlamydia Organisms as Revealed by Freeze-Etching and Negative Staining Techniques

1973 ◽  
Vol 116 (3) ◽  
pp. 1355-1363 ◽  
Author(s):  
Akira Matsumoto
Keyword(s):  
Negative Staining ◽  
Freeze Etching ◽  
Staining Techniques ◽  
Fine Structures ◽  
Cell Envelopes

scholarly journals IDENTIFICATION OF CHLOROPLAST COUPLING FACTOR BY FREEZE-ETCHING AND NEGATIVE-STAINING TECHNIQUES

1974 ◽  
Vol 63 (1) ◽  
pp. 24-34 ◽  
Author(s):  
Melvin P. Garber ◽  
Peter L. Steponkus
Keyword(s):  
Outer Surface ◽  
Complete Removal ◽  
Coupling Factor ◽  
Negative Staining ◽  
Chloroplast Coupling Factor ◽  
Freeze Etching ◽  
Staining Techniques ◽  
Spinach Leaves

Identification of chloroplast coupling factor particles, by the freeze-etching and negative-staining techniques, was made utilizing chloroplast thylakoids isolated from spinach leaves. Complete removal of particles, comparable in diameter to purified coupling factor particles, from the outer surface of freeze-etched thylakoids was achieved by treatment with 0.8% silicotungstate. Reappearance of particles, comparable in diameter to purified coupling factor particles, on the outer surface of freeze-etched thylakoids was demonstrated by combining silicotungstate-treated thylakoids with purified chloroplast coupling factor. Negative-staining results were in agreement with the freeze-etch data. The results demonstrate that the chloroplast coupling factor particles are exposed on the outer surface.

Polymer Morphology Revealed by Staining Techniques

1981 ◽  
Vol 39 ◽  
pp. 340-341
Author(s):  
A. C. Reimschuessel ◽  
V. Kramer
Keyword(s):  
Polymer Melt ◽  
Nylon 6 ◽  
Morphological Features ◽  
Negative Staining ◽  
Polymer Morphology ◽  
Crystallizable Polymer ◽  
Staining Techniques ◽  
Long Chain

Staining techniques can be used for either the identification of different polymers or for the differentiation of specific morphological domains within a given polymer. To reveal morphological features in nylon 6, we choose a technique based upon diffusion of the staining agent into accessible regions of the polymer.When a crystallizable polymer - such as nylon 6 - is cooled from the melt, lamellae form by chainfolding of the crystallizing long chain macromolecules. The regions between adjacent lamellae represent the less ordered amorphous domains into which stain can diffuse. In this process the lamellae will be “outlined” by the dense stain, giving rise to contrast comparable to that obtained by “negative” staining techniques.If the cooling of the polymer melt proceeds relatively slowly - as in molding operations - the lamellae are usually arranged in a radial manner. This morphology is referred to as spherulitic.

Evidence For Four Classes of Microtubules in Individual Cells

1967 ◽  
Vol 2 (2) ◽  
pp. 169-192
Author(s):  
O. BEHNKE ◽  
A. FORER
Keyword(s):  
Colchicine Treatment ◽  
Negative Staining ◽  
The Other ◽  
Pepsin Digestion ◽  
Sperm Tail ◽  
Staining Techniques ◽  
Cytoplasmic Microtubules ◽  
Experimental Treatments

Experiments were performed on crane-fly spermatids (Nephrotoma suturalis Loew), ratsperm, and rat tracheal cilia to test whether all microtubules respond in the same way to different treatments. Crane-fly spermatids contain cytoplasmic microtubules, accessory tubules, and the 9 + 2 complex of tubules; rat sperm and rat tracheal cilia contain only the 9 + 2 tubules. Crane-fly spermatid tubules responded to the experimental treatments as follows. After colchicine treatment, or storage at 0 °C, the cytoplasmic microtubules disappeared, while the 9 + 2 tubules were normal. After storage at 50 °C the cytoplasmic microtubules disappeared, and then the 9 + 2 tubules were affected: first the central tubules and B-tubules were affected, and later the A-tubules. After brief pepsin treatment, the 9 doublet tubules disappeared, while the other tubules appeared normal; after prolonged pepsin treatment the accessory, central, and cytoplasmic tubules disappeared. After negative staining at pH 7, the cytoplasmic microtubules were never seen, the central tubules were only sometimes seen, the B-tubules were sometimes fragmented, and the A-tubules were intact. On the basis of these responses, it was concluded that there are 4 classes of tubules in crane-fly spermatids, namely cytoplasmic microtubules; accessory tubules and central tubules (of the 9 + 2 complex); B-tubules (of the 9 + 2 complex); and A-tubules (of the 9 + 2 complex). At least some of the different responses appeared to be due to intrinsic physical and/or chemical differences between the tubules themselves. Pepsin digestion and negative staining of rat sperm tails gave results similar to those with crane-fly spermatids. In addition, the 9 + 2 tubules responded differently to pepsin digestion at different points along their length. This gradient of sensitivity was attributed to synthesis of new tubules occurring at one end of the sperm tail. Pepsin digestion and negative staining of rat tracheal cilia gave results similar to those with crane-fly spermatids and rat sperm tails. All the tubules had a similar substructure, as revealed by negative-staining techniques. It was concluded that microtubules are proteinaceous, at least in part, and that microtubules are different in composition from membranes. It is suggested that the walls of the B-tubules are composed of two materials--(1) the portions adjacent to the A-tubules, and (2) the remaining portion.

Two distinct negative staining patterns of halobacterium cell envelopes

1987 ◽  
Vol 45 ◽  
pp. 740-741
Author(s):  
Martin Kessel ◽  
E. Loren Buhle ◽  
Simone Cohen ◽  
Ueli Aebi
Keyword(s):  
Hexagonal Lattice ◽  
Dead Sea ◽  
Uranyl Acetate ◽  
Negative Staining ◽  
Freezing And Thawing ◽  
True Negative ◽  
Shadow Casting ◽  
High Resolution Analysis ◽  
Resolution Analysis ◽  
Cell Envelopes

The cell walls of Halobacteria are comprised of a 200,000MW sulphated glycoprotein, and by shadow casting are seen as a periodic hexagonal lattice of morphological units with a center to center spacing of approximately 140A. Preparations ot virtually salt tree envelopes from Halobacterium volcanii isolated from the Dead Sea, obtained by freezing and thawing the cells and suspension in 10mM CaCl2, have enabled high resolution analysis of the wall morphological units by negative staining.Envelopes of H. volcanii negatively stained with 1% uranyl acetate or 0.75% uranyl formate both at pH 4.5, have consistently resulted in two different images irrespective ot the stain used: a more prevalent “honeycomb” appearance of strong stain accumulating centers surrounded by regions ot stain exclusion (fig. 1 and fig. 3B); and a less common “true” negative staining with stain excluding rings (morphological units) and their stain accumulating centers lying in pools ot stain (Fig. 2 and 3A).

scholarly journals A FINE STRUCTURAL ANALYSIS OF INTERCELLULAR JUNCTIONS IN THE MOUSE LIVER

1970 ◽  
Vol 45 (2) ◽  
pp. 272-290 ◽  
Author(s):  
Daniel A. Goodenough ◽  
Jean Paul Revel
Keyword(s):  
Gap Junctions ◽  
Mouse Liver ◽  
Intercellular Junctions ◽  
Uranyl Acetate ◽  
Bile Canaliculus ◽  
Negative Staining ◽  
En Bloc ◽  
Intact Mouse ◽  
Zonula Occludens ◽  
Staining Techniques

Zonulae occludentes and gap junctions were examined both in the intact mouse liver and in a junction-rich membrane fraction from homogenized mouse liver. These preparations were visualized with the techniques of uranyl acetate staining en bloc, staining with colloidal lanthanum, negative staining with phosphotungstate, and freeze-cleaving. The zonula occludens is arranged as a meshwork of branching and anastomosing threadlike contacts sealing the lumen of the bile canaliculus from the liver intercellular space. The gap junction is characterized in section by a 20 A gap between the apposed junctional membrane outer leaflets, and permeation of this space with lanthanum or phosphotungstate reveals a polygonal lattice of subunits with a center-to-center spacing of 90–100 A. Freeze-cleaved gap junctions show a similar lattice. Extraction of junction-rich fractions with 60% aqueous acetone results in a disappearance of the 20 A gap in sectioned pellets and an inability to demonstrate the polygonal lattice with either the freeze-cleave or negative staining techniques. Extraction of the membranes with 50% acetone does not produce this effect. Thin-layer chromatography of the acetone extracts reveals a group of phospholipids in the 60% extract that are not detectable in the 50% extract. Acetone does not cause any detectable change in the structure of the zonula occludens, but the occluding junction becomes leaky to lanthanum following acetone treatment. The effects of other reagents on the junctions are reported.

Observation of a Central Subunit in Annelid Extracellular Hemoglobins using the Stem Digital Image Processing Techniques

1982 ◽  
Vol 40 ◽  
pp. 704-705
Author(s):  
M. Ohtsuki ◽  
A. V. Crewe
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Digital Image Processing ◽  
Digital Image ◽  
Negative Staining ◽  
Image Processing Techniques ◽  
Staining Techniques ◽  
Processing Techniques

Extracellular hemoglobins of annelids consist of 12 subunits with appearance of superposed hexagons. So far, electron microscopy using negative staining techniques indicated that only the hemoglobins of Nephtys and Oenone contain an additional central subunit.

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