scholarly journals Human meiosis I. The human pachytene karyotype analyzed by three dimensional reconstruction of the synaptonemal complex

1977 ◽  
Vol 42 (4) ◽  
pp. 283-323 ◽  
Author(s):  
Preben Bach Holm ◽  
Søren Wilken Rasmussen
Keyword(s):  
Synaptonemal Complex ◽  
Three Dimensional ◽  
Three Dimensional Reconstruction ◽  
Dimensional Reconstruction ◽  
Pachytene Karyotype ◽  
Meiosis I

The synaptonemal complexes of Achlya recurva (Oomycetes): karyotype analysis and three-dimensional reconstruction of pachytene nuclei in antheridia and oogonia

1991 ◽  
Vol 69 (6) ◽  
pp. 1384-1395 ◽  
Author(s):  
Hobart R. Williamson ◽  
Pesach Ben Yitzchak
Keyword(s):  
Synaptonemal Complex ◽  
Organizer Region ◽  
Nucleolar Organizer Region ◽  
Nucleolus Organizer Region ◽  
Three Dimensional ◽  
Central Element ◽  
Three Dimensional Reconstruction ◽  
Synaptonemal Complexes ◽  
Sequence Of Events ◽  
Dimensional Reconstruction

Fifteen synaptonemal complexes, as determined by three-dimensional reconstruction of serial, ultrathin sections, were present within both antheridial and oogonial zygotene and pachytene nuclei of the oomyceteous fungus Achlya recurva, thus n = 15. The present study represents the first complete reconstruction of synaptonemal complexes in the genus Achlya. The occurrence of both zygonema and pachynema was simultaneous in antheridia and oogonia. Pachytene nuclei of antheridia and oogonia are small, 13 μm3 in volume, and the average length of the synaptonemal complexes ranged from 1.9 to 4.4 μm. Lateral elements at zygotene ranged from 1.2 to 4.7 μm. Both ends of each synaptonemal complex were attached randomly to the nuclear envelope, so a bouquet formation was not observed at pachytene. In A. recurva, the dimensions of the synaptonemal complex were as follows: overall width = 270 nm; the lateral elements = 75 nm each in width and the central region = 120 nm. There was no central element and associated transverse filaments, which may be associated with development of alternative reproductive strategies other than amphimixis, as in nematodes. Of the 15 synaptonemal complexes present, only the one carrying the nucleolus organizer region could be clearly identified from one nucleus to the next. The nucleolar organizer region was on the average 0.75 μm from the telomere in both zygotene and pachytene nuclei. There were an average of three recombination nodules in each nucleus. Synaptonemal complexes have been reported in over 80 different species of fungi and related protista. Karyotypic evolution in the oomycetes and fungi may be the result of poly-ploidization, followed by cytogenetic diversification involving aneuploidy and differing degrees of polyploidy. Such a sequence of events could explain the apparent polyphyletic formation of this group. Key words: karyotype, Oomycetes, pachytene, synaptonemal complexes, three-dimensional reconstruction.

An ultrastructural pachytene karyotype for Puccinia graminis f.sp. tritici

1992 ◽  
Vol 70 (2) ◽  
pp. 401-413 ◽  
Author(s):  
E. W. A. Boehm ◽  
J. C. Wenstrom ◽  
D. J. McLaughlin ◽  
L. J. Szabo ◽  
A. P. Roelfs ◽  
...  
Keyword(s):  
Key Words ◽  
Synaptonemal Complex ◽  
Electron Micrographs ◽  
Three Dimensional ◽  
Chromosome Length ◽  
Epifluorescence Microscopy ◽  
Puccinia Graminis ◽  
Morphological Markers ◽  
Dimensional Reconstruction ◽  
Pachytene Karyotype

The karyotype for Puccinia graminis f.sp. tritici was determined from reconstructions of electron micrographs of serially sectioned pachytene nuclei. Epifluorescence microscopy was used to select DAPI-stained, pachytene nuclei in teliospore protoplasts from which walls were mechanically removed. Selection increased the probability that pachytene nuclei could be found in the absence of morphological markers. Six pachytene nuclei were reconstructed from four geographically disparate North American isolates. One nucleus was used to obtain a computer-enhanced, three-dimensional reconstruction that could be rendered as rotatable colorized stereo pairs. A karyotype of n = 18 was determined for all six nuclei. The 18 bivalents varied only slightly in size, each ranging from 3.0 to 8.8% of the total length of the genome. Total genomic lengths also proved highly comparable among isolates. Centromeres were not found, precluding use of the centromeric index as an aid in karyotyping. Only the nucleolus-associated bivalent could be cross-correlated among the six reconstructed nuclei. Heterogeneity in length among, but not within, isolates was observed for this bivalent, suggesting that chromosome length may be polymorphic in P. graminis f.sp. tritici, despite a constant total number of chromosomes. Key words: chromosomes, heterobasidiomycete, synaptonemal complex, Uredinales.

Methods for three-dimensional reconstruction of cellular components within a thick section

1986 ◽  
Vol 44 ◽  
pp. 18-21
Author(s):  
J. Frank ◽  
B. F. McEwen ◽  
M. Radermacher ◽  
C. L. Rieder
Keyword(s):  
Tilt Angle ◽  
Tomographic Reconstruction ◽  
3D Structure ◽  
Three Dimensional ◽  
Thick Section ◽  
Three Dimensional Reconstruction ◽  
Axis Ratio ◽  
Dimensional Reconstruction ◽  
Cellular Components

The tomographic reconstruction from multiple projections of cellular components, within a thick section, offers a way of visualizing and quantifying their three-dimensional (3D) structure. However, asymmetric objects require as many views from the widest tilt range as possible; otherwise the reconstruction may be uninterpretable. Even if not for geometric obstructions, the increasing pathway of electrons, as the tilt angle is increased, poses the ultimate upper limitation to the projection range. With the maximum tilt angle being fixed, the only way to improve the faithfulness of the reconstruction is by changing the mode of the tilting from single-axis to conical; a point within the object projected with a tilt angle of 60° and a full 360° azimuthal range is then reconstructed as a slightly elliptic (axis ratio 1.2 : 1) sphere.

Three-Dimensional Reconstruction of Native Androctonus Australis Hemocyanin

1990 ◽  
Vol 48 (1) ◽  
pp. 452-453
Author(s):  
Nicolas Boisset ◽  
Jean-Christophe Taveau ◽  
Jean Lamy ◽  
Terence Wagenknecht ◽  
Michael Radermacher ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid Body ◽  
Body Surface ◽  
Three Dimensional ◽  
Staining Technique ◽  
Three Dimensional Reconstruction ◽  
Dimensional Reconstruction ◽  
View Reconstruction ◽  
Surface Representations ◽  
Top View

Hemocyanin, the respiratory pigment of the scorpion Androctonus australis is composed of 24 kidney shaped subunits. A model of architecture supported by many indirect arguments has been deduced from electron microscopy (EM) and immuno-EM. To ascertain, the disposition of the subunits within the oligomer, the 24mer was submitted to three-dimensional reconstruction by the method of single-exposure random-conical tilt series.A sample of native hemocyanin, prepared with the double layer negative staining technique, was observed by transmisson electron microscopy under low-dose conditions. Six 3D-reconstructions were carried out indenpendently from top, side and 45°views. The results are composed of solid-body surface representations, and slices extracted from the reconstruction volume.The main two characters of the molecule previously reported by Van Heel and Frank, were constantly found in the solid-body surface representations. These features are the presence of two different faces called flip and flop and a rocking of the molecule around an axis passing through diagonnally opposed hexamers. Furthermore, in the solid-body surface of the top view reconstruction, the positions and orientations of the bridges connecting the half molecules were found in excellent agreement with those predicted by the model.

Three-Dimensional Reconstruction of Two Forms of the Chaperonin GRO EL

1990 ◽  
Vol 48 (1) ◽  
pp. 258-259
Author(s):  
J.L. Carrascosa ◽  
G. Abella ◽  
S. Marco ◽  
M. Muyal ◽  
J.M. Carazo
Keyword(s):  
Three Dimensional ◽  
The Other ◽  
Two Dimensional ◽  
Series Method ◽  
Three Dimensional Reconstruction ◽  
Structural Components ◽  
E Coli ◽  
Dimensional Reconstruction ◽  
Morphogenetic Factors ◽  
Tilt Series

Chaperonins are a class of proteins characterized by their role as morphogenetic factors. They trantsiently interact with the structural components of certain biological aggregates (viruses, enzymes etc), promoting their correct folding, assembly and, eventually transport. The groEL factor from E. coli is a conspicuous member of the chaperonins, as it promotes the assembly and morphogenesis of bacterial oligomers and/viral structures.We have studied groEL-like factors from two different bacteria:E. coli and B.subtilis. These factors share common morphological features , showing two different views: one is 6-fold, while the other shows 7 morphological units. There is also a correlation between the presence of a dominant 6-fold view and the fact of both bacteria been grown at low temperature (32°C), while the 7-fold is the main view at higher temperatures (42°C). As the two-dimensional projections of groEL were difficult to interprete, we studied their three-dimensional reconstruction by the random conical tilt series method from negatively stained particles.

247: Three Dimensional Reconstruction of Nervature in Prostate: Confirming Cancer Related Axonogenesis

2006 ◽  
Vol 175 (4S) ◽  
pp. 82-82
Author(s):  
Gustavo Ayala ◽  
Rile Li ◽  
Hong Oai ◽  
Mohammad Sayeeddudin ◽  
Timothy C. Thompson ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Three Dimensional Reconstruction ◽  
Dimensional Reconstruction
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