A simple fracturing device for obtaining complementary replicas of freeze‐fractured and freeze‐etched suspensions and tissue fragments

Abstract

SUMMARY Techniques for obtaining complementary replicas have already been shown to be valuable in aiding the interpretation of electron micrographs of replicas of specimens prepared by freeze‐etching and freeze‐fracturing techniques, and in the recognition of artefacts. This paper describes a simple and efficient method of obtaining complementary pairs of replicas of all types of specimen. Ordinary hollow brass rivets are used as specimen holders and are frozen in an end‐to‐end position using a special pair of forceps. Up to six rivets are placed in a device consisting of a hinged plate held together with clamps against the force of small springs. When the clamps are released, the pair of rivets are separated, fracturing the specimens. The device is easily adapted for use in any type of freeze‐etching or high vacuum apparatus. On the example of Saccharomyces cerevisiae the application of the technique to the detection of artefacts in complementary replicas are described. It was shown that the fibrils observed on cross‐fractured cell walls are produced by plastic deformation of cell wall components.

S-layer based biomolecular imprinting

“…Moreover, it has to be noted that, contrary to SbpA, also the NIP shows an Anti-Sauerbrey behavior. [46][47][48] (ii) Moreover, in case the polymer does not absorb the residual water contained in the pores and cavities of the S-layer protein lattice, a "deep" imprint of the S-layer in the polymer will not be possible since the S-layer will be squeezed by the water lm and just the upper part of the protein lattice may contribute to the imprint. It is likely, that such "rigid" molecular thin lms affect the transverse motion of the sensor surface due to their moments of inertia more severely than single molecules.…”

A method for adapting the Leybold device for obtaining complementary replicas to the Balzers unit

“…The Leybold device for preparing complementary replicas and its mode of operation were described in detail by Sleytr & Umrath (1974a). The device ( Fig.…”

“…The technical problem of obtaining replicas of complementary fracture planes has been solved in different ways in a number of laboratories. The various methods in use can be divided into two groups: freeze-cleaving is done either under vacuum conditions (Steere & Moseley, 1970;Wehrli, Miihlethaler & Moor, 1970;Sleytr & Umrath, 1974a;Tonosaki & Yamamoto, 1974) or under the surface of a liquid gas such as nitrogen (Chalcroft & Bullivant;Sleytr, 1970a, b) or liquid helium (Sleytr, 1974;Sleytr & Umrath, 1974b).…”

“…We reported earlier on a new complementary replica devicet for freezecleaving under vacuum (Sleytr & Umrath, 1974a); it has the following advantages (1) Ordinary hollow rivets of different size are used as specimen holders, thus avoiding the use of complicated and expensive object carriers.…”

Freeze‐Fracturing of Biological Material With A New Specimen Table

“…This communication describes the preparation of various biological specimens sandwiched between two regular gold carriers and the fracturing with the aid of a new specimen table (Balzers P T 301). This method is similar to the technique used by other authors for freeze-fracturing monolayers of tissue cultures (Chiquet et al, 1975;Pfenninger & Rinderer, 1975;Collins et al, 1975;Pauli et ~1.~1977) and the production of complementary replicas (Miihlethaler et al, 1973;Sleytr & Umrath, 1974). Prior to freezing, all samples were sandwiched between two gold carriers in slightly different ways (Fig.…”