THE THREE-DIMENSIONAL RECONSTRUCTION OF THE XY CHROMOSOMAL PAIR IN HUMAN SPERMATOCYTES

The spatial reconstruction of the XY pair of chromosomes from human spermatocytes has been made by the study of serial sections 1000 A in thickness. The sex pair during zygotene-pachytene forms a condensed mass of chromatin that has two filamentous, electron-opaque cores: the long and the short core. During early pachytene both cores have a common ending region, about 0.4–0.8 µ long. This common end is a synaptonemal complex, and each of the cores forms a lateral element of that complex. The cores become more convoluted during middle pachytene forming "ringlike bodies." Nucleoli from spermatocytes have three distinct regions: (a) granular; (b) dense fibrillar; and (c) clear intermediate. Occasional association of the XY pair and the heteropycnotic "basal knobs" results in apparent association of nucleoli and the sex pair in a minority of cells. The evidence presented is interpreted as a strong support of the hypothesis of homologous regions in the human XY pair.

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Three-Dimensional Reconstruction Using Stereo Pairs from Serial Thick Sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100080249 ◽

1977 ◽

Vol 35 ◽

pp. 562-563

Author(s):

Robert Glaeser ◽

Thomas Bauer ◽

David Grano

Keyword(s):

Three Dimensional ◽

Dimensional Structure ◽

Serial Sections ◽

Thin Sections ◽

3 Dimensional ◽

Transmission Electron ◽

Freeze Dried ◽

Dimensional Reconstruction ◽

Stereo Imagery ◽

Whole Mounts

In transmission electron microscopy, the 3-dimensional structure of an object is usually obtained in one of two ways. For objects which can be included in one specimen, as for example with elements included in freeze- dried whole mounts and examined with a high voltage microscope, stereo pairs can be obtained which exhibit the 3-D structure of the element. For objects which can not be included in one specimen, the 3-D shape is obtained by reconstruction from serial sections. However, without stereo imagery, only detail which remains constant within the thickness of the section can be used in the reconstruction; consequently, the choice is between a low resolution reconstruction using a few thick sections and a better resolution reconstruction using many thin sections, generally a tedious chore. This paper describes an approach to 3-D reconstruction which uses stereo images of serial thick sections to reconstruct an object including detail which changes within the depth of an individual thick section.

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Three-dimensional reconstruction of brain images from serial sections using the Possum framework

Frontiers in Neuroinformatics ◽

10.3389/conf.fninf.2016.20.00053 ◽

2016 ◽

Vol 10 ◽

Author(s):

Majka Piotr ◽

W�jcik Daniel

Keyword(s):

Three Dimensional ◽

Serial Sections ◽

Three Dimensional Reconstruction ◽

Brain Images ◽

Dimensional Reconstruction

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

Canadian Journal of Botany ◽

10.1139/b91-178 ◽

1991 ◽

Vol 69 (6) ◽

pp. 1384-1395 ◽

Cited By ~ 2

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.

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