Computer-Assisted Analysis and Display of Nuclear Structures

Author(s):  
P.B. Moens

Quantitative electron microscopy of cells, organelles, or chromosomes gives information on the numbers, sizes, distribution and organization of the structures in question. In the case of the nucleus, quantitative information can be obtained on nuclear pores, spindle pole bodies, kinetochores, centromeres, microtubules, chromosomes, synaptonemal complexes, and nucleoli. Scanning electron microscopy of fractured specimens and transmission electron microscopy of spread preparations and high voltage TKM can give some of the information, but total information can best be obtained from a complete series of sections of the material. The analysis of photographic records, however, is cumbersome and the relevant information is often not readily visible. In this report some of the methods ia compiling quantitative information on the nucleus and its components are described.

Author(s):  
G. E. Korte ◽  
M. J. Song

While examining thin sections of regenerating rabbit retinal pigment epithelium (RPE) we observed profound changes in ultrastructure as the cells matured. To assist in studying this problem serial thick sections (0.25 μm) through regenerating RPE cells were studied by highvoltage electron microscopy (HVEM) and a computer program (STERECON) used to generate stereo reconstructions.Tissue was obtained from rabbits that received sodium iodate iv -- which destroys large expanses of RPE and permits examination of regeneration from surviving cells. One-two weeks after iodate administration the rabbits were euthanized, the eyes removed and tissue processed for transmission electron microscopy by routine procedures. Serial sections 0.25 μm thick were mounted on Formvar coated slot grids, stained with uranyl acetate and lead citrate and examined with an AEI EM7 1.2 MV HVEM at 1000 kV. Figure 1 illustrates observations made on six sections through the cell seen in Fig. 2. The cell was photographed at 5000x and printed as a montage at 15,000x.


2017 ◽  
Vol 15 (02) ◽  
pp. 1650041 ◽  
Author(s):  
M. Sh. Barkovskaya ◽  
A. G. Bogomolov ◽  
N. Yu. Knauer ◽  
N. B. Rubtsov ◽  
V. A. Kozlov

Telomere length is an important indicator of proliferative cell history and potential. Decreasing telomere length in the cells of an immune system can indicate immune aging in immune-mediated and chronic inflammatory diseases. Quantitative fluorescent in situ hybridization (Q-FISH) of a labeled (C3TA[Formula: see text] peptide nucleic acid probe onto fixed metaphase cells followed by digital image microscopy allows the evaluation of telomere length in the arms of individual chromosomes. Computer-assisted analysis of microscopic images can provide quantitative information on the number of telomeric repeats in individual telomeres. We developed new software to estimate telomere length. The MeTeLen software contains new options that can be used to solve some Q-FISH and microscopy problems, including correction of irregular light effects and elimination of background fluorescence. The identification and description of chromosomes and chromosome regions are essential to the Q-FISH technique. To improve the quality of cytogenetic analysis after Q-FISH, we optimized the temperature and time of DNA-denaturation to get better DAPI-banding of metaphase chromosomes. MeTeLen was tested by comparing telomere length estimations for sister chromatids, background fluorescence estimations, and correction of nonuniform light effects. The application of the developed software for analysis of telomere length in patients with rheumatoid arthritis was demonstrated.


2006 ◽  
Vol 12 (4) ◽  
pp. 302-310 ◽  
Author(s):  
Yung-Ching Chien ◽  
Alfonso Mucci ◽  
Jeanne Paquette ◽  
S. Kelly Sears ◽  
Hojatollah Vali

The bulk morphology and surface features that developed upon precipitation on micrometer-size calcite powders and millimeter-size cleavage fragments were imaged by three different microscopic techniques: field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) of Pt-C replicas, and atomic force microscopy (AFM). Each technique can resolve some nanoscale surface features, but they offer different ranges of magnification and dimensional resolutions. Because sample preparation and imaging is not constrained by crystal orientation, FE-SEM and TEM of Pt-C replicas are best suited to image the overall morphology of microcrystals. However, owing to the decoration effect of Pt-C on the crystal faces, TEM of Pt-C replicas is superior at resolving nanoscale surface structures, including the development of new faces and the different microtopography among nonequivalent faces in microcrystals, which cannot be revealed by FE-SEM. In conjunction with SEM, Pt-C replica provides the evidence that crystals grow in diverse and face-specific modes. The TEM imaging of Pt-C replicas has nanoscale resolution comparable to AFM. AFM yielded quantitative information (e.g., crystallographic orientation and height of steps) of microtopographic features. In contrast to Pt-C replicas and SEM providing three-dimensional images of the crystals, AFM can only image one individual cleavage or flat surface at a time.


1986 ◽  
Vol 80 (1) ◽  
pp. 253-268
Author(s):  
K. Tanaka ◽  
T. Kanbe

Nuclear division in Schizosaccharomyces pombe has been studied in transmission electron micrographs of sections of cells fixed by a method of freeze-substitution. We have found cytoplasmic microtubules in the vicinity of the spindle pole bodies and two kinds of microtubules, short discontinuous ones and long, parallel ones in the intranuclear mitotic spindle. For most of the time taken by nuclear division the spindle pole bodies face each other squarely across the nuclear space but early in mitosis they briefly appear twisted out of alignment with each other, thereby imparting a sigmoidal shape to the bundle of spindle microtubules extending between them. This configuration is interpreted as indicating active participation of the spindle in the initial elongation of the dividing nucleus. It is proposed that mitosis is accompanied by the shortening of chromosomal microtubules simultaneously with the elongation of the central pole-to-pole bundle of microtubules of the intranuclear spindle. Daughter nuclei are separated by the sliding apart of interdigitating microtubules of the spindle at telophase. Some of the latter bear dense knobs at their ends.


Author(s):  
G. Pereira

Previous electron microscopic observations of the spleen have revealed the white pulp to be completely separated from the extravasated blood in the surrounding marginal zone by a strategically-located, double layer of reticular cells ensheathing a coarse reticular fiber. Similarly, a single reticular cell layer has been observed to form a continuous investment for all white pulp capillaries. To test the significance of this apparent isolation of the splenic white pulp from the blood, the distribution and composition of silver deposits in the spleen of argyric rats were determined by transmission and scanning electron microscopy coupled with computer-assisted x-ray analysis.Young male albino rats were made argyric by supplying them for many months with drinking water to which 1.5gm per liter of silver nitrate had been added. Specimens from the spleens of control and argyric animals were prepared for conventional transmission electron microscopy by glutaraldehyde-osmium fixation. For scanning electron microscopy, other specimens were fixed in buffered glutaraldehyde, freeze-dried in vacuo, coated with a thin film of gold- palladium and examined in a Cambridge Stereoscan Mark II.


2014 ◽  
Vol 50 (93) ◽  
pp. 14494-14497 ◽  
Author(s):  
Ashley Wragg ◽  
Martin R. Gill ◽  
Christopher J. Hill ◽  
Xiaodi Su ◽  
Anthony J. H. M. Meijer ◽  
...  

Dinuclear osmium(ii) complexes are excellent easy-to-handle probes for transmission electron microscopy, facilitating high-resolution intracellular imaging of sub-nuclear structures.


Sign in / Sign up

Export Citation Format

Share Document