Specific chromosome breakage at meiosis in C-heterochromatin mutants of the grasshopper Euchorthippus pulvinatus

1985 ◽  
Vol 27 (6) ◽  
pp. 644-649 ◽  
Author(s):  
J. L. Santos ◽  
N. Henriques-Gil ◽  
P. Arana
Keyword(s):  
Sister Chromatid ◽  
Meiotic Division ◽  
Chromosome Breakage ◽  
Specific Chromosome ◽  
Weak Point ◽  
Weak Points ◽  
Chromosome Breakages ◽  
Mutant Chromosome

Three males of Euchorthippus pulvinatus gallicus (Acrididae, Orthoptera) were found to be heterozygous for an enlarged interstitial C-block on the megameric chromosome, which usually has only small C-bands. These individuals exhibited a syndrome of chromosome breakages during the first meiotic division, the presence of the mutant C-bands being associated with the formation of specific weak points, as well as to an increase in sister chromatid cohesiveness. The pattern of breakage observed depends on the location of chiasmata relative to that of weak points and the enlarged C-block.Key words: C-heterochromatin mutant, chromosome breakage, weak point, sister chromatid cohesiveness.

Ethical-cultural Maps of Classical Greek Philosophy: the Contradiction between Nature and Civilization in Ancient Cynicism

Cultura ◽  
2019 ◽  
Vol 16 (1) ◽  
pp. 39-53
Author(s):  
Vytis VALATKA ◽  
Vaida ASAKAVIČIŪTĖ
Keyword(s):  
Swot Analysis ◽  
Greek Philosophy ◽  
Ancient Greek ◽  
Positive Aspect ◽  
Weak Point ◽  
Dio Chrysostom ◽  
Weak Points ◽  
Cultural Maps ◽  
Classical Greek Philosophy ◽  
Ancient Cynicism

This article restores the peculiar ethical-cultural cartography from the philosophical fragments of Ancient Greek Cynicism. Namely, the fragments of Anthistenes, Diogenes of Sinope, Crates, Dio Chrysostom as well as of the ancient historians of philosophy (Diogenes Laertius and Joanes Stobaeus) are mainly analyzed and interpreted. The methods of comparative analysis as well of rational restoration are applied in this article.The authors of the article concentrate on the main characteristics of the above mentioned cartography, that is, the contradiction between maps of nature and civilization. The article comes to the conclusion that the basis of this contradiction is the concept of the main value as well as virtue in the above mentioned cynicism, namely, natural radical temperance. According to ancient cynics, this virtue is absolutely incompatible with pleasure-driven civilization, as the latter annihilates the former. Therefore, cynics interpreted the whole territory of the world known at that time as divided between maps of nature and civilization that never overlap or even intersect. Moreover, according to ancient cynics, the territory covered by maps of civilization is considerably smaller than that enframed by the maps of nature. Moreover, the areas of nature are continuously being diminished, as civilization resolutely goes ahead. In such a situation that threatens survival of human nature the only possible way out is a return to the natural value of radical temperance. After cynics, the only effective strategy of achieving that challenging goal is askesis as excercises of temperance dedicated both to body and spirit.The authors of the article also give a certain SWOT analysis of the above mentioned cartography in the context of contemporary society. According to them, such a cartography possesses both strong and weak points. The main weak point is the contradiction itself between maps of culture and civilization. As a matter of fact, civilization does not annihilate the possibility of natural temperance, whereas a human being, according to his/her nature, is a creator of culture and civilization. On the other hand, the main positive aspect is an emphasis on virtue of temperance, which is actual, significant and relevant in any epoch, culture and civilization, and which is pretty much forgotten nowadays.

scholarly journals Chromosome breakage in yeast caused by sister-chromatid recombination in an integrated 2-micron plasmid

1982 ◽  
Vol 47 (6) ◽  
pp. 355-369 ◽  
Author(s):  
Steen Holmberg ◽  
Torsten Nilsson-Tillgren ◽  
Morten C. Kielland-Brandt ◽  
Jens G. Litske Petersen
Keyword(s):  
Sister Chromatid ◽  
Chromosome Breakage ◽  
2 Micron Plasmid ◽  
Sister Chromatid Recombination

Riyadh Chromosome Breakage Syndrome: Mental Retardation With Depigmentation of the Skin and Hair

1992 ◽  
Vol 7 (1_suppl) ◽  
pp. S79-S82 ◽  
Author(s):  
Pinar T. Ozand ◽  
Manjula Waghray ◽  
Jay D. Cook ◽  
Kirtikant Sheth ◽  
Generoso G. Gascon
Keyword(s):  
Mental Retardation ◽  
Sister Chromatid ◽  
Chromosome Breakage ◽  
Hair Color ◽  
Γ Irradiation ◽  
Exchange Frequency ◽  
Chromosome Breaks ◽  
Chromosome Breakage Syndrome ◽  
Sister Chromatid Exchange Frequency ◽  
Spontaneous Chromosome

A 20-month-old infant with "silvery-blond" hair color, widespread confettilike depigmentation of the skin, and mental retardation was found to have, in lymphocytes and fibroblast cultures, increased spontaneous chromosome breaks and breaks induced by both mitomycin and γ-irradiation. The sister chromatid exchange frequency was normal. This child probably represents a new chromosome breakage syndrome. (J Child Neurol 1992;7(Suppl):S79-S82.)

scholarly journals Structure-Specific Endonucleases and the Resolution of Chromosome Underreplication

Genes ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 232 ◽  
Author(s):  
Benoît Falquet ◽  
Ulrich Rass
Keyword(s):  
Sister Chromatid ◽  
Replication Fork ◽  
Genome Stability ◽  
Molecular Mechanisms ◽  
Chromosome Breakage ◽  
Repair Synthesis ◽  
Daughter Cells ◽  
Oncogene Activation ◽  
Dna Repair Synthesis ◽  
Replication Intermediates

Complete genome duplication in every cell cycle is fundamental for genome stability and cell survival. However, chromosome replication is frequently challenged by obstacles that impede DNA replication fork (RF) progression, which subsequently causes replication stress (RS). Cells have evolved pathways of RF protection and restart that mitigate the consequences of RS and promote the completion of DNA synthesis prior to mitotic chromosome segregation. If there is entry into mitosis with underreplicated chromosomes, this results in sister-chromatid entanglements, chromosome breakage and rearrangements and aneuploidy in daughter cells. Here, we focus on the resolution of persistent replication intermediates by the structure-specific endonucleases (SSEs) MUS81, SLX1-SLX4 and GEN1. Their actions and a recently discovered pathway of mitotic DNA repair synthesis have emerged as important facilitators of replication completion and sister chromatid detachment in mitosis. As RS is induced by oncogene activation and is a common feature of cancer cells, any advances in our understanding of the molecular mechanisms related to chromosome underreplication have important biomedical implications.

scholarly journals Chromosome Breakage and Sister Chromatid Exchange Frequencies in Scleroderma

1981 ◽  
Vol 24 (11) ◽  
pp. 1409-1413 ◽  
Author(s):  
Glenn K. Sherer ◽  
Barbara B. Jackson ◽  
E. Carwile Leroy
Keyword(s):  
Sister Chromatid ◽  
Sister Chromatid Exchange ◽  
Chromosome Breakage

scholarly journals ENVIROMENT-FRIENDLY FARMING PROJECTS IN LATGALE

2001 ◽  
Vol 1 ◽  
pp. 75
Author(s):  
Eduards Matisāns ◽  
Semjons Ivanovs
Keyword(s):  
Natural Resources ◽  
Social Development ◽  
Weak Point ◽  
The North ◽  
North Eastern ◽  
Weak Points ◽  
North Eastern Part

By evaluating the strong and the weak points o f the Latgale region we can assert that its power lies in its natural resources which are luxurious in their mild modesty, with the best-preserved environmental originality in the north-eastern part o f Eutrope. The weak point of Latgale is the poverty of the population and disarrayed infrastructure. To eliminate the weakness, balanced education o f the population is needed, as well as profitable farming projects and support investments. A co-operation project was worked out by the Latvian Council o f Science “Optimisation o f the economic and social development of Latgale During four years “Foundations o f farming in Latgale ” have been developed. This report deals with what has been done; in monographs, available just here, the members of the conference can obtain detailed information.

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