The Degradation of the Rhinovirion as Studied By High Resolution Stereo Electron Microscopy

Author(s):  
Jerry D. Reeves ◽  
Heather D. Mayor

Picornaviruses, a group of small RNA-containing viruses are further divided into two sub-groups, the enteroviruses which are acid stable, and the rhinoviruses which suffer marked loss of infectivity at acid pH. We have found a ninety per cent decrease in infectious titer after subjection to pH 5.5 as compared to the titer of the original material at pH 7. 0. Considerable morphological degradation of the virion, as monitored by electron microscopy, has also occurred by pH 5. 5. It appears that capsid breakdown proceeds through loss of a vertex capsomere group followed by release of the viral genome in the form of a ribonucleoprotein strand (Fig. 1). However, the conventional flattened electron microscopic image produced by these small virus particles makes further interpretation at a high resolution extremely difficult.

2016 ◽  
Vol 22 (4) ◽  
pp. 887-901 ◽  
Author(s):  
Elier Ekberg Neri-Torres ◽  
Jorge J. Chanona-Pérez ◽  
Hector A. Calderón ◽  
Neil Torres-Figueredo ◽  
German Chamorro-Cevallos ◽  
...  

AbstractThe objective of this work was to obtain Spirulina (Arthrospira maxima) nanoparticles (SNPs) by using high-impact mechanical milling and to characterize them by electron microscopy and spectroscopy techniques. The milling products were analyzed after various processing times (1–4 h), and particle size distribution and number mean size (NMS) were determined by analysis of high-resolution scanning electron microscopic images. The smallest particles are synthesized after 3 h of milling, had an NMS of 55.6±3.6 nm, with 95% of the particles being smaller than 100 nm. High-resolution transmission electron microscopy showed lattice spacing of ~0.27±0.015 nm for SNPs. The corresponding chemical composition was obtained by energy-dispersive X-ray spectroscopy, and showed the presence of Ca, Fe, K, Mg, Na, and Zn. The powder flow properties showed that the powder density was higher when the average nanoparticle size is smaller. They showed free flowability and an increase in their specific surface area (6.89±0.23 m2/g) up to 12–14 times larger than the original material (0.45±0.02 m2/g). Fourier transform infrared spectroscopy suggested that chemical damage related to the milling is not significant.


Author(s):  
E, R. Walker ◽  
N. O. Olson ◽  
M. H. Friedman

An unidentified virus, responsible for an arthritic-like condition in chickens was studied by electron microscopy and other methods of viral investigation. It was characterized in chorio-allantoic membrane (CAM) lesions of embryonating chicken eggs and in tissue culture as to: 1) particle size; 2) structure; 3) mode of replication in the cell; and 4) nucleic acid type.The inoculated virus, coated and uncoated, is first seen in lysosomal-like inclusions near the nucleus; the virions appear to be uncoated in these electron dense inclusions (Figure 1), Although transfer of the viral genome from these inclusions is not observable, replicating virus and mature virus crystals are seen in the cytoplasm subsequent to the uncoating of the virions.The crystals are formed in association with a mass of fibrils 50 to 80 angstroms in diameter and a ribosome-studded structure that appears to be granular endoplasmic reticulum adapted to virus replication (Figure 2). The mature virion (Figure 3) is an icosahedral particle approximately 75 millimicrons in diameter. The inner core is 45 millimicrons, the outer coat 15 millimicrons, and the virion has no envelope.


Author(s):  
J. A. Pollock ◽  
M. Martone ◽  
T. Deerinck ◽  
M. H. Ellisman

Localization of specific proteins in cells by both light and electron microscopy has been facilitate by the availability of antibodies that recognize unique features of these proteins. High resolution localization studies conducted over the last 25 years have allowed biologists to study the synthesis, translocation and ultimate functional sites for many important classes of proteins. Recently, recombinant DNA techniques in molecular biology have allowed the production of specific probes for localization of nucleic acids by “in situ” hybridization. The availability of these probes potentially opens a new set of questions to experimental investigation regarding the subcellular distribution of specific DNA's and RNA's. Nucleic acids have a much lower “copy number” per cell than a typical protein, ranging from one copy to perhaps several thousand. Therefore, sensitive, high resolution techniques are required. There are several reasons why Intermediate Voltage Electron Microscopy (IVEM) and High Voltage Electron Microscopy (HVEM) are most useful for localization of nucleic acids in situ.


Clay Minerals ◽  
1985 ◽  
Vol 20 (2) ◽  
pp. 255-262 ◽  
Author(s):  
S. Mann ◽  
R. M. Cornell ◽  
U. Schwertmann

Aluminium-substituted goethites are found in many soils and can also be synthesised readily in the laboratory. In recent years, synthetic substituted goethites have been examined by various techniques including XRD, IR, TEM and dissolution kinetics (Thiel, 1963; Jonas & Solymar, 1970; Fey & Dixon, 1981; Fysh & Fredericks, 1983; Schulze & Schwertmann, 1984; Schwertmann, 1984). Transmission electron microscopy (TEM) studies have shown that as Al substitution rises above 10%, the goethite needles become shorter and also thicker in the a direction. Furthermore, crystals which at zero substitution consist of domains parallel to the c axis become less domainic with increasing Al substitution (Schulze & Schwertmann, 1984).


1997 ◽  
Vol 3 (S2) ◽  
pp. 353-354
Author(s):  
William R. McManus ◽  
Donald J. McMahon

Models for the structure of the bovine casein micelle have been proposed in the past (1,2,3,4). These models are based on the chemical and physical properties of the micelles and fall into two general catagories, framework and submicelle models. Electron Microscopy techniques were one of the tools used in the development of these models. However, no definative model has been established. We have developed a new electron microscopy method and it is being applied to the re-examination of the protein structure of the casein micelle, with the goal of establishing a definative model for the structure of the casein micelle.High resolution scannning electron microscopy has proven unsuccessful in revealing the protein structure in the casein micelle (Fig 1). To create high resolution scanning electron microscopic images, fine metal coatings are required in the 5 to l0nm range. Following the application of these coatings, images of casein micelles resemble a melting lumpy sphere. This is due to the metal layer obscuring the proteins from view.


2004 ◽  
Vol 12 (1) ◽  
pp. 3-7
Author(s):  
Stephen W. Carmichael ◽  
Jon Charlesworth

The use of fluorescent probes is becoming more and more common in cell biology. It would be useful if we were able to correlate a fluorescent structure with an electron microscopic image. The ability to definitively identify a fluorescent organelle would be very valuable. Recently, Ying Ren, Michael Kruhlak, and David Bazett-Jones devised a clever technique to correlate a structure visualized in the light microscope, even a fluorescing cell, with transmission electron microscopy (TEM).Two keys to the technique of Ren et al are the use of grids (as used in the TEM) with widely spaced grid bars and the use of Quetol as the embedding resin. The grids allow for cells to be identified between the grid bars, and in turn the bars are used to keep the cell of interest in register throughout the processing for TEM. Quetol resin was used for embedding because of its low auto fluorescence and sectioning properties. The resin also becomes soft and can be cut and easily peeled from glass coverslips when heated to 70°C.


Author(s):  
Ronald Glaser ◽  
Ross Farrugia

Several laboratories have reported that simian virus 40 (SV40) was rescued from transformed cells when the nonproducing cells were cocultivated or fused in the presence of ultraviolet inactivated Sendai virus (UV-SV), to potentially susceptible cells. Evidence obtained from studies in which nuclei from heterokaryons were isolated and separated on density gradients, indicated that rescued virus was first detected in the transformed nuclei of the heterokaryons formed during cell fusion. The present study was performed to determine how long after fusion SV40 virus particles could be found in the nuclei of the heterokaryons and to investigate the site of rescue by electron microscopy.


2012 ◽  
Vol 18 (S5) ◽  
pp. 3-4 ◽  
Author(s):  
M. C. Proença ◽  
J. F. Moura Nunes ◽  
A. P. Alves de Matos

Automatic image processing of transmission electron microscopy images (TEM) is a utopia often pursued, considering the thousands of images necessary to ensure a high resolution 3D reconstruction of virus particles or other macromolecular machines.


1967 ◽  
Vol 33 (3) ◽  
pp. 679-708 ◽  
Author(s):  
Tsuranobu Shirahama ◽  
Alan S. Cohen

The ultrastructural organization of the fibrous component of amyloid has been analyzed by means of high resolution electron microscopy of negatively stained isolated amyloid fibrils and of positively stained amyloid fibrils in thin tissue sections. It was found that a number of subunits could be resolved according to their dimensions. The following structural organization is proposed. The amyloid fibril, the fibrous component of amyloid as seen in electron microscopy of thin tissue sections, consists of a number of filaments aggregated side-by-side. These amyloid filaments are approximately 75–80 A in diameter and consist of five (or less likely six) subunits (amyloid protofibrils) which are arranged parallel to each other, longitudinal or slightly oblique to the long axis of the filament. The filament has often seemed to disperse into several longitudinal rows. The amyloid protofibril is about 25–35 A wide and appears to consist of two or three subunit strands helically arranged with a 35–50-A repeat (or, less likely, is composed of globular subunits aggregated end-to-end). These amyloid subprotofibrillar strands measure approximately 10–15 A in diameter.


1994 ◽  
Vol 126 (4) ◽  
pp. 901-910 ◽  
Author(s):  
T J Deerinck ◽  
M E Martone ◽  
V Lev-Ram ◽  
D P Green ◽  
R Y Tsien ◽  
...  

A simple method is described for high-resolution light and electron microscopic immunolocalization of proteins in cells and tissues by immunofluorescence and subsequent photooxidation of diaminobenzidine tetrahydrochloride into an insoluble osmiophilic polymer. By using eosin as the fluorescent marker, a substantial improvement in sensitivity is achieved in the photooxidation process over other conventional fluorescent compounds. The technique allows for precise correlative immunolocalization studies on the same sample using fluorescence, transmitted light and electron microscopy. Furthermore, because eosin is smaller in size than other conventional markers, this method results in improved penetration of labeling reagents compared to gold or enzyme based procedures. The improved penetration allows for three-dimensional immunolocalization using high voltage electron microscopy. Fluorescence photooxidation can also be used for high resolution light and electron microscopic localization of specific nucleic acid sequences by in situ hybridization utilizing biotinylated probes followed by an eosin-streptavidin conjugate.


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