Freeze-etching technique

Riehie U and Hdchii M 1973 The theory and technique of high pressure freezing Freeze-Etching Technique and Appiications ed E L Benedetti and P Favard (Paris Societe Frangaise de Microscopie Eiectronique) pp 31-61... 

Schmidt, D.G., Buchheim, W., Koops, J. 1971. An electron-microscopic study of fat-protein complexes in evaporated milk, using the freeze-etching technique. Neth. Milk Dairy J. 25, 200-216. 

In addition to being able to fit in the evaporator, the sample must tolerate the conditions required for the vacuum evaporation of the metal film and carbon backing. The specimen must be virtually dry, i.e., it must not give off appreciable or uncontrolled amounts of water vapor in the evaporator. This can be accomplished by either drying the specimen or keeping the entrained water frozen at a temperature that precludes significant sublimation [discussed under freeze-etch techniques (see Section 2.4.5.4)]. 

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. 

The cell wall in yeast contains some D-glucan and D-mannans that form fibrillar strands (see p. 302). Investigation of yeast cells by the freeze-etching technique (see p. 338) provided the first evidence for the formation of microfibrils by plasmalemma. During this... 

Freeze-etching Technique in which water is evaporated under vacuum from the freeze-fractured surface of a specimen before the observation with electron microscopy. 

The morphology of the capsule of a strain of E. coli has been examined by freeze-etching techniques. The effects of increasing concentrations of antibodies on the capsular structure, the location of the sites of synthesis of the capsular polysaccharide, and the export of the capsular polysaccharide were reported for a temperature-sensitive mutant. In addition to a Iiis-linked gene, a frp-Iinked gene is required for the synthesis of the complete K27(A) capsular polysaccharide of E. coli 08 K27. ... 

J. H. M. Willison and A. J. Rowe, Replica, Shadowing and Freeze-etching Techniques , in Practical 264. 

An alternative method is the freeze-etching technique [24, 25], which consists of producing platinum shadowed replicas of fractures created in rapidly frozen biological systems or lyotropic liquid crystals. The fracture orientation is somewhat haphazard, but occurs preferentially within the paraffinic level of the bilayers. These methods offer the possibility of viewing bilayers directly and preparing stereoviews. Beautiful pictures of liquid crystalline DNA, both cholesteric and hexagonal, have been obtained, but individual molecules are not easily resolved. However, the director distribution can be deduced from the images [26],... 

Microtomy and freeze-etching techniques have revealed many similarities between liquid crystals and a large series of biological materials, which show the same symmetries as nematic, smectic and cholesteric phases, but without being fluid [27-34]. The biological materials are stabilized... 

Benedetti, E.L., and Favaerd, R, Freeze Etching Techniques and Applications, Soci6t6 Franpaise de Microscopie Electronique, 1973. 

On the basis of X-ray diffraction studies, the ultrastructure of chloroplast membrane has been analyzed by Kreutz - s, and the subject reviewed by him. Using the freeze-etching technique, Muehlethaler has suggested a picture for the thylakoid membrane based upon the bimolecular leaflet model. The salient feature in all these proposed models lies in their oriented bilayer lipid core, onto which other important cellular constituents, such as proteins and pigments, may interact through either ionic or van der Waals attraction, or both. Muehlethaler s interpretation is of special interest, in view of the experiments using the pigmented... 

---