Chromatin elimination in the hypotrichous ciliate Stylonychia mytilus

Chromosoma ◽  
1980 ◽  
Vol 77 (3) ◽  
pp. 285-297 ◽  
Author(s):  
G. F. Meyer ◽  
H. J. Lipps
Keyword(s):  
Chromatin Elimination ◽  
Stylonychia Mytilus

Разработка интегративного критерия безопасности продуктов питания

2015 ◽  
pp. 14-21
Author(s):  
Валерий Васильевич Воробьев
Keyword(s):  
Tetrahymena Pyriformis ◽  
Stylonychia Mytilus

В статье рассматриваются ускоренные методы определения токсичности пищевого сырья и продуктов питания на основе использования инфузорий Tetrahymena pyriformis и Stylonychia mytilus. Показано, что применение экспресс-метода с использованием стилонихий по определению общей токсичности лососевой икры, пресервов из соленой кеты, горбуши и сельди с различными консервантами, по сравнению с методикой определения уровня токсичности с помощью тетрахимены, позволяет сократить продолжительность констатации в 5 – 16 раз.

scholarly journals Boon and Bane of DNA Double-Strand Breaks

2021 ◽  
Vol 22 (10) ◽  
pp. 5171
Author(s):  
Ingo Schubert
Keyword(s):  
Negative Impact ◽  
Biological Effects ◽  
Double Strand Breaks ◽  
Immunoglobulin Gene ◽  
Dna Double Strand Breaks ◽  
Endogenous Factors ◽  
Strand Breaks ◽  
Chromatin Elimination ◽  
Evolutionary Consequences ◽  
Cell Lethality

DNA double-strand breaks (DSBs), interrupting the genetic information, are elicited by various environmental and endogenous factors. They bear the risk of cell lethality and, if mis-repaired, of deleterious mutation. This negative impact is contrasted by several evolutionary achievements for DSB processing that help maintaining stable inheritance (correct repair, meiotic cross-over) and even drive adaptation (immunoglobulin gene recombination), differentiation (chromatin elimination) and speciation by creating new genetic diversity via DSB mis-repair. Targeted DSBs play a role in genome editing for research, breeding and therapy purposes. Here, I survey possible causes, biological effects and evolutionary consequences of DSBs, mainly for students and outsiders.

Synthese und Abbau der Nucleins�uren w�hrend der Entwicklung des Makronukleus von Stylonychia mytilus (Protozoa, Ciliata)

Chromosoma ◽  
1968 ◽  
Vol 25 (2) ◽  
pp. 107-120 ◽  
Author(s):  
Dieter Ammermann
Keyword(s):  
Stylonychia Mytilus

Microsurgically generated discontinuities provoke heritable changes in cellular handedness of a ciliate, Stylonychia mytilus

Development ◽  
1991 ◽  
Vol 111 (2) ◽  
pp. 337-356
Author(s):  
X.B. Shi ◽  
Z.I. Qiu ◽  
W. He ◽  
J. Frankel
Keyword(s):  
Large Scale ◽  
Mirror Image ◽  
The Other ◽  
Left Edge ◽  
Left Handed ◽  
Specific Manner ◽  
The Right ◽  
Anteroposterior Polarity ◽  
Posterior Anterior ◽  
Stylonychia Mytilus

Stylonychia mytilus is a dorsoventrally flattened ciliate with compound ciliary structures arranged in a specific manner on the cell surface. In mirror-image (MI) doublets of this ciliate, two nearly complete sets of ciliary structures are arrayed side-by-side, one in a normal or ‘right-handed’ (RH) arrangement, the other in a reversed or ‘left-handed’ (LH) arrangement. MI-doublets exist in two forms, one with the RH component on the right, the LH component on the left, and feeding structures near the center (‘buccal-adjoining MI-doublet’); the other with the RH component on the left, the LH component on the right, and feeding structures on the lateral edges (‘buccal-opposing MI-doublet’). We describe an operation that can generate either type of MI-doublet. This operation interchanges large anterior and posterior regions of the cell, transposing the original posterior region anteriorly (P—A) and the original anterior region posteriorly (A—P), while retaining the original anteroposterior polarity of each region. Two sets of new ciliary structures then are formed in mirror-image arrangement, with the set in the P—A region oriented normally and the set in the A—P region undergoing a reversal of polarity along its anteroposterior axis. This sometimes creates end-to-end MI forms, but more commonly produces side-by-side MI-doublets through a folding together of the P—A and A—P regions. This folding occurs because one lateral edge of the cell had been removed during the operation; if the left edge was removed, the complex folds to the left and forms a buccal-adjoining MI-doublet, whereas if the right edge was removed, the complex folds to the right and forms a buccal-opposing MI-doublet. Both types can reorganize and later divide true-to-type, although the ‘buccal-opposing’ type is by far the more stable of the two. The generation of mirror-image forms is dependent on the prior abnormal juxtaposition of regions from opposite ends of the cell, and involves a coordinated respecification of large-scale organization. We interpret this response to be a consequence of intercalation of missing intervening positional values in the zone of posterior-anterior abutment.

Chromatin Elimination Induced by the B Chromosome of Maize

1973 ◽  
Vol 64 (1) ◽  
pp. 13-18 ◽  
Author(s):  
M. M. RHOADES ◽  
ELLEN DEMPSEY
Keyword(s):  
B Chromosome ◽  
Chromatin Elimination

Electron-Microscopic Observations on the Macronuclear Development of Stylonychia Mytilus and Tetrahymena Pyriformis (Ciliophora-Protozoa)

1973 ◽  
Vol 13 (2) ◽  
pp. 479-509 ◽  
Author(s):  
K. G. MURTI
Keyword(s):  
Dna Synthesis ◽  
Nuclear Membrane ◽  
Fibrous Material ◽  
Structural Changes ◽  
Degradation Products ◽  
Polytene Chromosomes ◽  
Tetrahymena Pyriformis ◽  
Nucleotide Sequences ◽  
Macronuclear Development ◽  
Stylonychia Mytilus

This report describes an ultrastructural investigation of macronuclear development following conjugation in Stylonychia mytilus (a spirotrichous ciliate) and Tetrahymena pyriformis (a holotrichous ciliate). In S. mytilus, polytene chromosomes are formed in the young macronucleus (macronuclear Anlage). They are subsequently broken between the bands by ‘membranous’ partitions; the assembly of the membranes appears to be concomitant with the formation of the polytene chromosomes. The membranes in the Anlage appear to originate from fibrous material seen in the early Anlage. This fibrous material in the earlier stages is seen concentrated at several points along the border of the inner nuclear membrane. In the later stages it is seen in the interior of the Anlage, outlining the developing polytene chromosomes. As the chromosomes reach the maximum degree of polyteny, the fibrous material condenses to acquire a membranous appearance and extends into the interband regions. The Anlage throughout this period shows a progressive increase in size. Subsequently, the membranes enclose individually each band plus portions of the 2 adjacent interband regions of the polytene chromosomes to form a large number of vesicles. After vesicle formation the Anlage shrinks, and the chromatin inside the vesicles shows degradative changes. Finally, the vesicles disappear, the membrane degradation products appear at the nuclear membrane, and the Anlage now contains nucleoli. The Anlage increases its DNA content by multiple rounds of replication to become a mature macronucleus. The ultra-structural changes observed in the Anlage support the idea of genetic diminution (i.e. extensive DNA synthesis, elimination of many DNA nucleotide sequences, and amplification of the remaining DNA nucleotide sequences in a second period of DNA synthesis) proposed earlier on the basis of cytochemical, biochemical, and limited electron-microscope studies. In T. pyriformis, the macronuclear development differs substantially from that of Stylonychia. Features such as the formation and degradation of polytene chromosomes are absent in the macronuclear development of Tetrahymena; the young macronucleus in this cell becomes a mature macronucleus by progressive increment in size and chromatin content with no apparent genetic diminution. These observations agree with cytochemical studies on the macronuclear development of Tetrahymena.

Loss of electrical excitability during encystment of the hypotrichous ciliate Stylonychia mytilus

1987 ◽  
Vol 74 (3) ◽  
pp. 140-142 ◽  
Author(s):  
J. W. Deitmer
Keyword(s):  
Electrical Excitability ◽  
Stylonychia Mytilus

Persistent hyperthermia induces adaptive modulations in the cytology of ciliates Stylonychia mytilus and Euplotes aediculatus

1989 ◽  
Vol 14 (2) ◽  
pp. 75-81 ◽  
Author(s):  
Sunil C. Kaul ◽  
G.R. Sapra
Keyword(s):  
Stylonychia Mytilus

Die Paarungsreaktion von Stylonychia mytilus Müller

1951 ◽  
Vol 6 (1) ◽  
pp. 45-47 ◽  
Author(s):  
Karl G . Grell
Keyword(s):  
Stylonychia Mytilus

Abstract Bei Stylonychia mytilus geht der Konjugation ein eigenartiges "Paarungsspiel" voraus, das zum Unterschied von der bei Paramaecium-Arten beschriebenen "agglutinative reaction" in einzelnen, regelmäßig aufeinanderfolgenden Phasen besteht und mehrfach wiederholt wird, bevor sich die beiden Partner endgültig vereinigen.

scholarly journals Electron microscopy of chromatin elimination in Cidaria (Lepidoptera)

Hereditas ◽  
2009 ◽  
Vol 80 (1) ◽  
pp. 35-39 ◽  
Author(s):  
MARJA SORSA ◽  
ESKO SUOMALAINEN
Keyword(s):  
Electron Microscopy ◽  
Chromatin Elimination
Sign in / Sign up

Export Citation Format

Share Document