Freeze etching electron microscopy

Conventional electron microscopy (Devine et al 1972) and freeze-etch (Somlyo Franzini-Armstrong 1985) of VSMCs reveals that the jSR is separated from overlying PL by a 12—15nm cytosolic space that is traversed by electron-dense structures. These structures appear similar to the foot processes of cardiac and skeletal muscle (Franzini-Armstrong et al 1998). Indeed, there is striking structural similarity between these PL—jSR regions in VSMC and the diads and triads of cardiac and skeletal muscle (Franzini-Armstrong et al 1998). Moreover,... 

Verkleij, A.J., Zwaal, R.F., Roelofsen, B., Comfurius, P., KasteUjn, D. and van Deenen, L.L.M., 1973, The asymmetric distribution ofphosphoUpids in the human red cell membrane. A combined study using phospholipases and freeze-etch electron microscopy. 

These results were confirmed by an electron microscopy study using a freeze-etching replication technique (1 ). The aim of this technique was to conserve the real gel structure by blocking any diffusion processes in the gel sample by the freezing action of liquid nitrogen. The three-dimensional network is then recovered... 

Fig. 8 Different views of T. foetus hydrogenosomes ( ) after field-emission scanning electron microscopy (FESEM) (a) and freeze-etching (b,c). An isolated hydrogenosome obtained from T. foetus observed by FESEM, where details of its surface can be seen, b A calcium deposit in the peripheral vesicle (asterisk) c shows that the peripheral vesicle (arrow) presents a smooth surface, distinct from the organelle body. Bars = 50 nm. (From Benchimol 2000)...

Figure 18-2 (A) Schematic diagram of mitochondrial structure. (B) Model showing organization of particles in mitochondrial membranes revealed by freeze-fracture electron microscopy. The characteristic structural features seen in the four half-membrane faces (EF and PF) that arise as a result of fracturing of the outer and inner membranes are shown. The four smooth membrane surfaces (ES and PS) are revealed by etching. From Packer.8...

Various electron microscopy techniques have been used to study the structures of whippable emulsions such as normal and cryo-scanning electron microscopy or transmission electron microscopy using various preparation methods such as freeze fracturing, freeze etching, etc. The literature is quite extensive, and only a few important papers will be discussed in this chapter. 

Hanson PI, Roth R, Morisaki H, Jahn R, Heuser JE (1997) Structure and conformational changes in NSF and its membrane receptor complexes visualized by quick-freeze/deep-etch electron microscopy. Cell 90 523-35... 

The most thorough study of the formation of artificial casein micelles is that of Schmidt and co-workers (1977 1979 Schmidt and Koops, 1977 Schmidt and Both, 1982 Schmidt and Poll, 1989), who not only studied the properties of the casein aggregates but also attempted to relate them to the solution conditions under which they were formed. In the precipitation of calcium phosphate from solution, the means by which solutions are mixed together is of crucial importance Schmidt et al. (1977) described a method in which four solutions were pumped simultaneously into a reaction vessel while keeping the pH constant. As a result of careful, slow mixing, the reproducibility of the size distributions of particles, measured by electron microscopy on freeze-fractured and freeze-etched specimens, was very good. In the first series of experiments, the objective was to produce milk like concentrations of the most important ions while... 

The surface layer of the fat globule may act as a catalytic impurity (e.g., when it contains mono-glycerides or di-glycerides with long-chain fatty acid residues) however, there is still some uncertainty as to whether this process actually occurs (see Walstra, 1995). Although concentric layers of apparently crystalline fat have been observed in electron micrographs of freeze-etched or freeze-fractured milk or cream samples (Buchheim, 1970 Henson et al., 1971), these observations could not be confirmed by other microscopy techniques. Noda and Yamamoto (1994) reported that it is thermodynamically more favorable for fat crystals to be located at the oil/water interface, rather than in the interior of the droplet, which may explain the presence of fat crystals at the membrane. 

Freeze-etch electron microscopy of P pili revealed that they are composite fibers consisting of two distinct structures (Kuehn et ai, 1992) (see later. Fig. 8). The stalk of the pilus is composed of repeating monomers... 

Ghadially EN, Lock CJL, Lalonde JMA, Ghadially R. Platinosomes produced in synovial membrane by platinum coordination complexes. Virchows Arch., B, Cell Pathol. 1981 35 123-131. Beretta GL, Righetti SC, Lombardi L, Zunino F, Perego P. Electron microscopy analysis of early localization of cisplatin in ovarian carcinoma cells. Ultrastruct. Pathol. 2002 26 331-334. Ruben GC. Ultrathin (Inm) vertically shadowed platinum-carbon replicas for imaging individual molecules in freeze-etched biological DNA and material science metal and plastic specimens. J. Electron. Microsc. Tech. 1989 13 335-354. 

Bailey, A. and Bisalputra, T., 1970. A preliminary account of the application of thinsec-tioning, freeze-etching, and scanning electron microscopy to the study of coralline algae. Phycologia, 9 83—101. 

Further evidence for the light-driven proton translocation by bacteriorhodopsin was obtained by Racker and Stoeckenius who carried out reconstitution ofthe purple membrane into phospholipid vesicles. In the light, the reconstituted vesicles took up protons from the exterior at a rate of 50-200 ng per mg of bacteriorhodopsin, and released them in the dark. The rate of proton uptake in the fight and release in the dark was accelerated by the addition ofvalinomycin, while uncouplers of oxidative phosphorylation abolished the uptake of protons altogether. Note that the direction of proton transport from outside to the inside of the vesicle reported by the authors was opposite to that observed in intact cells, the possibility that bacteriorhodopsin might be oppositely oriented in cells and vesicles, was subsequently confirmed by freeze-etch electron microscopy. 

Transmission electron microscopy thin-sectioning, negative staining, freeze etching, mica-technique, cryo-TEM Atomic force microscopy... 

J. H. M. Willison and A. J. Rowe, Replica, Shadowing and Freeze-etching Techniques , in Practical Methods in Electron Microscopy, Vol. 8 (ed. A. M. Glauert), North-Holland, Amsterdam, 1980, pp. 31-55. 

The presence of liquid-crystalline material at the emulsion interface has been shown by electron microscopy using the freeze-etching technique 18). Typical liquid-crystalline structures are shown in Figure 16. These liquid-crystalline compositions are viscous, and the lamellar phase displays pseudoplastic rheology. The lamellar phase is the most important of all liquid-crystalline phases for emulsion stability. The presence of a liquid-crystalline phase causes a reduction of the available London-van der Waals forces for coalescence 16). As a consequence of the reduction of the influence of these dispersion forces and the high viscosity of the liquid-crystal layer, the time for coalescence is increased dramatically. 

H. Gong, J. Ruberti, D. Overby, M. Johnson, T.F. Freddo, A new view of the human trabecular meshwork using quick-freeze, deep-etch electron microscopy, Exp. Eye Res. 75 (2002) 347-358. 

The structure of this type of L2 phase has been analyzed by electron microscopy and by X-ray diffraction [6]. The results indicate that flexible disk-shaped water micelles occur, separated by lipid bilayers. The X-ray data are in agreement with electron micrographs of freeze-etched freeze-fractured samples. An analysis of the X-ray scattering results at a weight ratio of monoglyceride to water of 8 2 gave these results ... 

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