Freeze-fracture cytochemistry: A goal set by Russell Steere in 1957

1993 ◽  
Vol 51 ◽  
pp. 60-61
Author(s):  
Nicholas J Severs
Keyword(s):  
Chemical Nature ◽  
Biological Systems ◽  
Freeze Fracture ◽  
Structural Components ◽  
Major Goal ◽  
Membrane Biology ◽  
Routine Application ◽  
The Future ◽  
Freeze Etching

In his pioneering demonstration of the potential of freeze-etching in biological systems, Russell Steere assessed the future promise and limitations of the technique with remarkable foresight. Item 2 in his list of inherent difficulties as they then stood stated “The chemical nature of the objects seen in the replica cannot be determined”. This defined a major goal for practitioners of freeze-fracture which, for more than a decade, seemed unattainable. It was not until the introduction of the label-fracture-etch technique in the early 1970s that the mould was broken, and not until the following decade that the full scope of modern freeze-fracture cytochemistry took shape. The culmination of these developments in the 1990s now equips the researcher with a set of effective techniques for routine application in cell and membrane biology.Freeze-fracture cytochemical techniques are all designed to provide information on the chemical nature of structural components revealed by freeze-fracture, but differ in how this is achieved, in precisely what type of information is obtained, and in which types of specimen can be studied.

Low temperature SEM comparisons of adjacent freeze-fractured and freeze-etched areas on frozen, hydrated samples

1995 ◽  
Vol 53 ◽  
pp. 1066-1067
Author(s):  
William P. Wergin ◽  
Eric F. Erbe ◽  
Robert W. Yaklich
Keyword(s):  
Low Temperature ◽  
Biological Samples ◽  
Freeze Fracture ◽  
Structural Components ◽  
Freeze Fracturing ◽  
Water Ice ◽  
Virus Particles ◽  
Structural Details ◽  
Freeze Etching ◽  
Sem Imaging

Most biological samples contain 70-95% water, consequently cryofixation and freeze-fracturing result in relatively smooth surfaces that exhibit few structural details. Freeze-etching, a technique that solved this problem, was initially developed for TEM observations of virus particles by Steere nearly 40 years ago. The technique, which sublimes water-ice from the surface of a fractured sample, produces surface topography that corresponds to the structural components on the freeze-etched face. This technique was further enhanced by recovering the complementary halves of a fractured sample, etching one of the surfaces and then comparing the complementary replicas from the freeze-fractured and freeze-etched faces. Recently, similar techniques were used on frozen, hydrated samples to examine complementary halves of freeze-fractured, freeze-etched specimens by low temperature SEM. Imaging complementary images of frozen, hydrated specimens in the SEM was faster than imaging complementary replicas in the TEM, however the procedure required specialized holders and was technically demanding.To simplify comparisons of freeze-fracture, freeze-etch images, samples were frozen, fractured and etched in the prechamber of an Oxford CT 1500 HF Cryotrans system that was attached to a Hitachi S-4100 FESEM.

Freeze-Fracture Replication of Frozen Outer Segments of Rat Retinal Rods

1969 ◽  
Vol 27 ◽  
pp. 392-393
Author(s):  
Thomas S. Leeson ◽  
C. Roland Leeson
Keyword(s):  
Electron Microscopy ◽  
Cross Section ◽  
Outer Segment ◽  
Freeze Fracture ◽  
X Ray Diffraction ◽  
X Ray ◽  
Outer Segments ◽  
Retinal Rods ◽  
Temperature Electron ◽  
Freeze Etching

Numerous previous studies of outer segments of retinal receptors have demonstrated a complex internal structure of a series of transversely orientated membranous lamellae, discs, or saccules. In cones, these lamellae probably are invaginations of the covering plasma membrane. In rods, however, they appear to be isolated and separate discs although some authors report interconnections and some continuities with the surface near the base of the outer segment, i.e. toward the inner segment. In some species, variations have been reported, such as longitudinally orientated lamellae and lamellar whorls. In cross section, the discs or saccules show one or more incisures. The saccules probably contain photolabile pigment, with resulting potentials after dipole formation during bleaching of pigment. Continuity between the lamina of rod saccules and extracellular space may be necessary for the detection of dipoles, although such continuity usually is not found by electron microscopy. Particles on the membranes have been found by low angle X-ray diffraction, by low temperature electron microscopy and by freeze-etching techniques.

Rate of Sublimation of Ice by Radiative Heating in Freeze-Etching

1980 ◽  
Vol 38 ◽  
pp. 618-619
Author(s):  
Yeshayahu Talmon
Keyword(s):  
Heat Flux ◽  
Freeze Fracture ◽  
Constant Heat Flux ◽  
Radiative Heating ◽  
Constant Heat ◽  
Entire Sample ◽  
Simplified Method ◽  
Freeze Etching ◽  
Sublimation Rates ◽  
Fractured Surface

To bring out details in the fractured surface of a frozen sample in the freeze fracture/freeze-etch technique,the sample or part of it is warmed to enhance water sublimation.One way to do this is to raise the temperature of the entire sample to about -100°C to -90°C. In this case sublimation rates can be calculated by using plots such as Fig.1 (Talmon and Thomas),or by simplified formulae such as that given by Menold and Liittge. To achieve higher rates of sublimation without heating the entire sample a radiative heater can be used (Echlin et al.). In the present paper a simplified method for the calculation of the rates of sublimation under a constant heat flux F [W/m2] at the surface of the sample from a heater placed directly above the sample is described.

scholarly journals Understanding Hydrogen Sulfide in Inflammation: Opportunities and Challenges

2019 ◽  
Author(s):  
Madhav Bhatia
Keyword(s):  
Hydrogen Sulfide ◽  
Tissue Damage ◽  
Adaptive Response ◽  
Inflammatory Diseases ◽  
Biological Systems ◽  
Future Prospects ◽  
Disease Research ◽  
The Future

Inflammation is an adaptive response to injury, but uncontrolled inflammation can lead to tissue damage and disease. Research in our laboratory (since confirmed in different laboratories worldwide) has shown that hydrogen sulfide (H2S) acts as a mediator of inflammation in different disease conditions. Learning about a novel mediator of inflammation results in unique opportunities with which to approach inflammatory diseases. At the same time, the complexity of biological systems and translation of research from the bed to the bedside also presents challenges. This Editorial aims to discuss the opportunities and challenges in relation to the role of H2S in inflammation, and the future prospects for this research.

Dynamics of changes in the structural components of the mucosa and cartilage of the larynx of rats at the end of 28th and 35th days of experimental opioid exposure

2021 ◽  
pp. 79-88
Author(s):  
Khrystyna P. Ivasivka ◽  
Evgeniy V. Paltov ◽  
Zoryana Z. Masna ◽  
Yuri Ya. Kryvko ◽  
Maryana B. Cherkes
Keyword(s):  
Mucous Membrane ◽  
Structural Components ◽  
Fundamental Study ◽  
The Future ◽  
And Cartilage

In our work we aimed to conduct a fundamental study of the process of morphological disorganization of the structural components of the mucous membrane and cartilage of the larynx at the end of the 28 and 35 days of experimental opioid effects at the microstructural level. This information in the future will allow to form a pathomorphological base, which will be used to compare the components of the mucous membrane and cartilage of the larynx in the norm with the dynamics of their changes as a result of experimental opioid effects at different times.

7. The lawless pursuit of biological systems

2020 ◽  
pp. 108-122
Author(s):  
Eberhard O. Voit
Keyword(s):  
Systems Biology ◽  
Biological Systems ◽  
Large Classes ◽  
The Future

The laws of physics are a prerequisite for us to make reliable predictions regarding our surroundings. By extension, making reliable predictions in biology requires laws of biology. The problem is that such laws are almost non-existent, because biological systems are hugely complex and diverse. As a consequence, it is difficult to make true statements covering all organisms on Earth—or even large classes of organisms. This difficulty translates directly into the challenge of identifying rules that govern biological systems. What would such biological rules or laws even look like? ‘The lawless pursuit of biological systems’ considers the future of systems biology and discusses how it might evolve as it matures as a field of investigation.

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