High resolution metal replication, quantified by image processing of periodic test specimens

Gross, Heinz; Müller, Tobias; Wildhaber, Ivo; Winkler, Hanspeter

doi:10.1016/0304-3991(85)90098-1

Cited by 69 publications

(36 citation statements)

References 35 publications

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“…3A). This was predictable; grain size increases with increased coating temperature (Gross et al, 1985), and structural alterations may have occurred due to complete hydration before coating. The optimal thickness of the metal layer decreased with the lowering of temperature.…”

Section: Discussionmentioning

confidence: 98%

High resolution biological scanning electron microscopy: A comparative study of low temperature metal coating techniques

Hermann¹,

Müller²

1991

J. Elec. Microsc. Tech.

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Structural information on the surface of biological specimens can be resolved within molecular dimensions by "in-lens" field emission scanning electron microscopes when cryo-methods are used to adequately preserve the native state of the specimen. The visual definition of molecular surface structures depends largely on the metal coating. The thickness of the coating, as well as the temperature at which it is deposited, are among the most important parameters affecting visual definition. These were evaluated on T4 polyheads and T4D phages using chromium double-axis rotary shadowing (DARS). Micrographs of optimally DARS coated T4 polyheads and T4D phages were compared with chromium planar-magnetron sputtering (PMS) and unidirectional shadowing with platinum/carbon. Metal deposition was carried out at low temperatures during all three procedures. Optimal visual definition of structural details on the surface of DARS coated T4 polyheads and T4D phages (capsomeres of T4 polyheads and their subunits with diameters of 8 and 3 nm; T4D phage tail fibres with a thickness of 3 nm) is achieved at a thickness of the chromium film greater than the minimum required for metal film coalescence. Chromium DARS coating at room temperature resulted in poor structural definition, whereas DARS at specimen temperatures of -85 degrees C and -150 degrees C, with the chromium thickness optimized for each temperature, yielded good visual detail of polyhead substructures. The visual definition was slightly reduced when DARS coating was carried out at a specimen temperature of -250 degrees C. Adequate structural visibility of T4D phage and T4 polyhead surface structures was achieved with the three coating techniques tested.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 98%

High resolution biological scanning electron microscopy: A comparative study of low temperature metal coating techniques

Hermann¹,

Müller²

1991

J. Elec. Microsc. Tech.

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“…Gross et al (1985) suggest that it is wise to apply both replication modes in combination, as they provide complementary information. With rotary replication, the rotation speed should be adjusted so that the deposition rate is not greater than 0.05 nm/sec (Gross et al, 1985).…”

Section: Replication Methodsmentioning

confidence: 97%

“…4,6,7,8) gives a finer grain than platinumkarbon (Pt/C) replication (Figs. 3, 5, 9, lo), as reported by Bachmann et al (1969Bachmann et al ( , 1985 and Gross et al (1985). Ta/W replicas are on average 0.2 nm thick (i.e., 10-20% of the thickness of PtlC replicas as measured by a quartz crystal monitor).…”

Section: Replication Methodsmentioning

confidence: 99%

Freeze‐Fracture, Deep‐Etch, and Freeze‐Substitution Studies of Olfactory Epithelia, With Special Emphasis on Immunocytochemical Variables

Menco

1995

Microscopy Res & Technique

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Freeze-fracturing and deep-etching are a well-suited set of methods to study membrane and cytoplasmic features. Various approaches are available. Possible variables include tissue preparation, fracturing only or fracturing followed by etching, modes and materials of replication, and various ways of combining freeze-fracturing and/or deep-etching with (immuno)cytochemistry. Freeze-substitution, in particular combined with embedding in methacrylate resins such as the Lowicryls, is becoming rather widely accepted for purposes of ultrastructural (immuno)cytochemistry. Most investigators active in this field agree that this combination yields superior results compared to (immuno)cytochemistry combined with more conventional means of thin section transmission electron microscopy. Yet relatively little information is available on the variations that can occur with different approaches of freeze-substitution immunocytochemistry. This review deals with some of the variations in freeze-fracturing, freeze-etching, and freeze-substitution as applied to olfactory epithelial structures and with the effectiveness of observations obtained by application of the above sets of methods in relating the special morphology of olfactory epithelial cellular structures with those obtained by other approaches. Indeed, the data obtained continue to provide an integral image in which that morphology can be related to the special biochemistry, cell and molecular biology, and electrophysiology of olfactory epithelial structures.

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“…To circumvent problems with the interpretation of images often caused by the negative stain method, the octamer's surface topography was replicated by evaporation of heavy metal at low object temperature [18]. Unidirectional shadowing led to the perspective impression of the surface of the octamer with its four hill-like quadrants.…”

Section: Structure Of the Mi-ck Octamer By Electron Microscopymentioning

confidence: 99%

The structure of mitochondrial creatine kinase and its membrane binding properties

Schnyder¹,

Rojo

Furter³

et al. 1994

Mol Cell Biochem

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The biochemical and biophysical characterization of the mitochondrial creatine kinase (Mi-CK) from chicken cardiac muscle is reviewed with emphasis on the structure of the octameric oligomer by electron microscopy and on its membrane binding properties. Information about shape, molecular symmetry and dimensions of the Mi-CK octamer, as obtained by different sample preparation techniques in combination with image processing methods, are compared. The organization of the four dimeric subunits into the Mi-CK complex as apparent as apparent in the end-on projections is discussed and the consistently observed high binding affinity of the four-fold symmetric end-on faces towards many support films and towards each other is outlined. A study on the oligomeric state of the enzyme in solution and in intact mitochondria, using chemical crosslinking reagents, is presented together with the results of a search for a possible linkage of Mi-CK with the adenine nucleotide translocator (ANT). The nature of Mi-CK binding to model membranes, demonstrating that rather the octameric than the dimeric subspecies is involved in lipid interaction and membrane contact formation, is resumed and put into relation to our structural observations. The findings are discussed in light of a possible in vivo function of the Mi-CK octamer bridging the gap between outer and inner mitochondrial membranes at the contact sites.

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High resolution metal replication, quantified by image processing of periodic test specimens

Cited by 69 publications

References 35 publications

High resolution biological scanning electron microscopy: A comparative study of low temperature metal coating techniques

High resolution biological scanning electron microscopy: A comparative study of low temperature metal coating techniques

Freeze‐Fracture, Deep‐Etch, and Freeze‐Substitution Studies of Olfactory Epithelia, With Special Emphasis on Immunocytochemical Variables

The structure of mitochondrial creatine kinase and its membrane binding properties

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