Intramembrane Particles in the Postsynaptic Membranes of the S-, F-, and C-Type Synapses by Freeze-Fracturing, and Deep-Etching Studies on the Xenopus Spinal Cord

1991 ◽  
pp. 349-354
Author(s):  
Hiroshi Watanabe ◽  
Hiroshi Washioka ◽  
Akira Tonosaki
Keyword(s):  
Spinal Cord ◽  
Freeze Fracturing ◽  
Deep Etching ◽  
Intramembrane Particles

scholarly journals Cross-linking of erythrocyte membrane proteins by periodate and intramembrane particle distribution

1978 ◽  
Vol 171 (3) ◽  
pp. 683-686 ◽  
Author(s):  
C G Gahmberg ◽  
I Virtanen ◽  
J Wartiovaara
Keyword(s):  
Human Erythrocyte ◽  
Particle Distribution ◽  
Sodium Periodate ◽  
Erythrocyte Membranes ◽  
Cross Linking ◽  
Freeze Fracturing ◽  
Intramembrane Particle ◽  
Intramembrane Particles ◽  
Human Erythrocyte Membranes ◽  
Erythrocyte Membrane Proteins

Treatment of isolated human erythrocyte membranes at pH 7.4 with 0.1-0.5 mM-sodium periodate specifically cross-linked some of the spectrin polypeptides. Treatment with 2 mM-periodate resulted in complete cross-linking of spectrin and partial cross-linking of other polypeptides. The latter treatment also caused aggregation of the intramembrane particles made visible by freeze-fracturing. When membranes that had been treated with 2 mM-periodate were depleted of spectrin by treatment with 0.1 mM-EDTA, extensive aggregation of the intramembrane particles occurred.

Mobility of Chloroplast Coupling Factor 1 (CF1) at the Thylakoid Surface as Revealed by Freeze-Etching after Antibody Labelling

1974 ◽  
Vol 29 (11-12) ◽  
pp. 694-699 ◽  
Author(s):  
Richard Berzborn ◽  
Friedrich Kopp ◽  
Kurt Mühlethaler
Keyword(s):  
Outer Surface ◽  
Coupling Factor ◽  
Freeze Fracturing ◽  
Deep Etching ◽  
Chloroplast Coupling Factor ◽  
Freeze Etching ◽  
Chloroplast Coupling Factor 1 ◽  
Number Of Particles ◽  
Antibody Labelling

Abstract Freeze-Etching Freeze-fracturing and 60 sec deep-etching of isolated chloroplast thylakoid systems exposed large areas of the outer surface (matrix side) of the thylakoids. If the thylakoid systems were first treated with antisera against chloroplast coupling factor 1 (CF1), the 14 nm particles at the outer surface appeared aggregated. Between clusters these particles were absent. Since there is no change in the number of particles/area after treatment with antibodies, it is concluded that the 14 nm particles are mobile within the surface of the thylakoid. The antisera contained only anti­bodies against CF1 ; therefore the 14 nm particles at the outer surface are identified to be CF1 . The implication of a mobile ATP-synthetase (CF1) for the mechanisms of photophosphorylation is discussed.

Freeze-fracturing of presynaptic membranes in the central nervous system

1971 ◽  
Vol 261 (839) ◽  
pp. 387-387 ◽  
Keyword(s):  
Spinal Cord ◽  
Optic Tectum ◽  
Synaptic Vesicles ◽  
Nerve Terminals ◽  
Rat Spinal Cord ◽  
Freeze Fracturing ◽  
Membrane Surfaces ◽  
Frozen Tissue ◽  
The Central Nervous System ◽  
Presynaptic Nerve Terminals

That synaptic vesicles with a diameter of about 50 nm could be demonstrated by the freeze-fracturing technique was an important contribution to the knowledge of synaptic fine structure (Moor, Pfenninger & Akert 1969; Akert, Moor, Pfenninger & Sandri 1969). The finding u spheric profiles (figures 1, 3 a, c) in rapidly frozen tissue renders an artefactual origin of vesicles very unlikely. However, the chief advantage of freeze-fracturing lies in the visualization of membrane surfaces which are of special interest in presynaptic nerve terminals. The present micrographs were obtained from freeze-fractured monkey, cat, and rat spinal cord, cerebral cortex, and subfornical organ as well as from pigeon optic tectum. Special attention was paid to areas in which large pieces of membranes remained attached to the surfaces of nerve cells (figures 1, 3 a ). This situation suggests a special type of affinity between the two elements, and the association of one of the membranes with clusters of synaptic vesicles indicates that presynaptic membranes may be involved.

Identification of Intramembrane Particles by Pre- and Post-Fracture Labelling Techniques: A Progress Report

1980 ◽  
Vol 38 ◽  
pp. 692-695
Author(s):  
J. E. Rash ◽  
T. J. A. Johnson ◽  
C. S. Hudson ◽  
D. S. Copio ◽  
W. F. Graham ◽  
...  
Keyword(s):  
Neuromuscular Junctions ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Glycerol Solution ◽  
Protein Markers ◽  
Replica Technique ◽  
Deep Etching ◽  
Intramembrane Particles ◽  
Membrane Surfaces ◽  
Macromolecular Architecture

Conventional freeze-fracture replicas provide for high resolution, three-dimensional replication of the internal macromolecular architecture of cell membranes, but they have the distinct disadvantage that no biologically rele¬vant macromolecules remain for subsequent in situ labelling and positive identification. Recently, several ingenious freeze-fracture techniques have been devised to localize biochemical components before the tissues are diges-ted away. These methods include (a) freeze-fracture autoradiography of the frozen whole mount preparation (1, 2) and (b) deep etching (freeze-drying) to expose immunoglobins or other large protein markers attached to membrane surfaces (3). However, freeze-fracture autoradiography has insufficient resolution to permit localization of labels to individual intramembrane particles (IMPs) exposed by the cleaving process, while deep etching to reveal membrane surfaces does not reveal IMPs. To overcome some of these difficulties, we recently introduced the "sectioned replica technique" to provide a method for direct and unambiguous correlation of freeze-fracture and thin section images within a single electron micrograph (4). The fractured and replicated tissues are thawed, but instead of digesting the tissues, the replica-tissue sandwich is post-fixed in 30% buffered glycerol solution con-taining 1% OsO4, post-stained, embedded in plastic, and sectioned parallel to the replica-tissue interface. Using this sectioned-replica technique, we have been able to obtain (a) pre-fracture radioisotope-labelled mouse neuromuscular junctions and (b) pre- and post-fracture immunoferritin and colloidal gold-labelled membrane fragments and intact neuromuscular junctions.

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