scholarly journals The molecular structure of the DNA fragments eliminated during chromatin diminution in Cyclops kolensis

2004 ◽  
Vol 14 (11) ◽  
pp. 2287-2294 ◽  
Author(s):  
S. Degtyarev
Keyword(s):  
Molecular Structure ◽  
Dna Fragments ◽  
Chromatin Diminution ◽  
Cyclops Kolensis

Chromatin Diminution in Cyclops kolensis Lill. (Copepoda, Crustacea) as a Radical Way to Inactivate Redundant Genome in Somatic Cells

2018 ◽  
Vol 156 (3) ◽  
pp. 165-172 ◽  
Author(s):  
Andrey K. Grishanin ◽  
Maxim V. Zagoskin
Keyword(s):  
Chromosome Number ◽  
Repetitive Sequences ◽  
Early Embryogenesis ◽  
Chromosome Size ◽  
Chromatin Diminution ◽  
Elimination Process ◽  
Dna Elimination ◽  
Molecular Studies ◽  
Cyclops Kolensis

Chromatin diminution (CD) is a phenomenon of programmed DNA elimination which takes place in early embryogenesis in some eukaryotes. The mechanism and biological role of CD remain largely unknown. During CD in the freshwater copepod Cyclops kolensis, the genome of cells of the somatic lineage is reorganized and reduced in size by more than 90% without affecting the genome of germline cells. Although the diploid chromosome number is unchanged, chromosome size is dramatically reduced by CD. The eliminated DNA consists primarily of repetitive sequences and localizes within granules during the elimination process. In this review, we provide an overview of CD in C. kolensis including both cytological and molecular studies.

Electronic and molecular structure of M-DNA fragments

2010 ◽  
Vol 17 (5) ◽  
pp. 997-1006 ◽  
Author(s):  
Yury V. Rubin ◽  
Leonid F. Belous ◽  
Аnatolij А. Yakuba
Keyword(s):  
Molecular Structure ◽  
Dna Fragments

Chromatin diminution in the copepod Mesocyclops edax: elimination of both highly repetitive and nonhighly repetitive DNA

Genome ◽  
2013 ◽  
Vol 56 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Christian McKinnon ◽  
Guy Drouin
Keyword(s):  
Repetitive Dna ◽  
Tandem Repeats ◽  
Repetitive Sequences ◽  
Embryonic Cells ◽  
Chromatin Diminution ◽  
Developmentally Regulated ◽  
Dna Elimination ◽  
Eukaryotic Species ◽  
Cyclops Kolensis ◽  
Mesocyclops Edax

Chromatin diminution, a developmentally regulated process of DNA elimination, is found in numerous eukaryotic species. In the copepod Mesocyclops edax, some 90% of its genomic DNA is eliminated during the differentiation of embryonic cells into somatic cells. Previous studies have shown that the eliminated DNA contains highly repetitive sequences. Here, we sequenced DNA fragments from pre- and postdiminution cells to determine whether nonhighly repetitive sequences are also eliminated during the process of chromatin diminution. Comparative analyses of these sequences, as well as the sequences eliminated from the genome of the copepod Cyclops kolensis, show that they all share similar abundances of tandem repeats, dispersed repeats, transposable elements, and various coding and noncoding sequences. This suggests that, in the chromatin diminution observed in M. edax, both highly repetitive and nonhighly repetitive sequences are eliminated and that there is no bias in the type of nonhighly repetitive DNA being eliminated.

scholarly journals Study of chromatin diminution in Cyclops kolensis (Copepoda, Crustacea) by radiobiological methods

2021 ◽  
Vol 15 (4) ◽  
pp. 329-338
Author(s):  
Andrey Grishanin ◽  
Oksana Chinyakova
Keyword(s):  
Experimental Results ◽  
Chromatin Diminution ◽  
Cell Stage ◽  
Cytoplasmic Factors ◽  
Cyclops Kolensis ◽  
Copepoda Cyclopoida

The experimental results show that at doses of 20 Gy and 100 Gy, the development of Cyclops kolensis Lilljeborg, 1901 (Copepoda, Cyclopoida) embryos ceases at the 16-cell stage, without affecting the course of chromatin diminution. A dose of 200 Gy terminated the process of chromatin diminution in some of the embryos. These results support the hypothesis that cytoplasmic factors in the egg play an important role in the process of chromatin diminution.

Molecular Structure of the Outermost Cell Wall Component of Spirillum Serpens

1977 ◽  
Vol 35 ◽  
pp. 342-343
Author(s):  
Wah Chiu ◽  
David Grano
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Outer Membrane ◽  
Gel Electrophoresis ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Cell Wall Component ◽  
Protein Components ◽  
Exposure Technique ◽  
Structural Aspects

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.

On the relation between isotope effects on vapour pressure and molecular structure

1963 ◽  
Vol 60 ◽  
pp. 52-55
Author(s):  
István Kiss ◽  
Lajos Matus ◽  
István Opauszky
Keyword(s):  
Molecular Structure ◽  
Vapour Pressure ◽  
Isotope Effects
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