A Note on the Effects of some Cytotoxic Substances on Amphibian Embryos

Development ◽  
1958 ◽  
Vol 6 (2) ◽  
pp. 363-364
Author(s):  
C. H. Waddington
Keyword(s):  
Cell Division ◽  
Giant Cells ◽  
Nitrogen Mustards ◽  
Restitution Nucleus ◽  
Avian Embryos ◽  
Cellular Degeneration ◽  
Amphibian Embryos

In connexion with the experiments of Jurand (1958) on the action of TEM on avian embryos, it seems worthwhile describing very shortly some observations on the effects of this substance, and also of Myleran, on early amphibian embryos. Bodenstein (1954 and earlier) has described some of the cytological results of the administration of various ‘radio-mimetic’ substances to amphibian embryos, including nitrogen mustards and TEM. The effects on the development of the eye were particularly considered, and they have also been discussed and illustrated by Töndury (1955). Two main types of damage were noted, the formation of giant cells, and of cellular degeneration accompanied by nuclear breakdown and the formation of deeply staining cytoplasmic lumps. The giant cells presumably arise from the suppression of cell-division followed by the formation of a restitution nucleus. These nuclei stain rather palely, and appear to be lacking in DNA.

scholarly journals Endopolyploidy in irradiated p53-deficient tumour cell lines: Persistence of cell division activity in giant cells expressing Aurora-B kinase

2008 ◽  
Vol 32 (9) ◽  
pp. 1044-1056 ◽  
Author(s):  
Jekaterina Erenpreisa ◽  
Andrei Ivanov ◽  
Sally P. Wheatley ◽  
Elizabeth A. Kosmacek ◽  
Fiorenza Ianzini ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Lines ◽  
Tumour Cell ◽  
Giant Cells ◽  
Aurora B ◽  
Aurora B Kinase ◽  
Tumour Cell Lines

scholarly journals Arabidopsis sepals: A model system for the emergent process of morphogenesis

2021 ◽  
Vol 2 ◽  
Author(s):  
Adrienne H. K. Roeder
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Cell Division ◽  
Slow Growth ◽  
Expression Patterns ◽  
Giant Cells ◽  
Model System ◽  
Gene Expression Patterns ◽  
Emergent Properties ◽  
Correct Size

Abstract During development, Arabidopsis thaliana sepal primordium cells grow, divide and interact with their neighbours, giving rise to a sepal with the correct size, shape and form. Arabidopsis sepals have proven to be a good system for elucidating the emergent processes driving morphogenesis due to their simplicity, their accessibility for imaging and manipulation, and their reproducible development. Sepals undergo a basipetal gradient of growth, with cessation of cell division, slow growth and maturation starting at the tip of the sepal and progressing to the base. In this review, I discuss five recent examples of processes during sepal morphogenesis that yield emergent properties: robust size, tapered tip shape, laminar shape, scattered giant cells and complex gene expression patterns. In each case, experiments examining the dynamics of sepal development led to the hypotheses of local rules. In each example, a computational model was used to demonstrate that these local rules are sufficient to give rise to the emergent properties of morphogenesis.

scholarly journals Virus-induced cell gigantism and asymmetric cell division in archaea

2021 ◽  
Vol 118 (15) ◽  
pp. e2022578118 ◽  
Author(s):  
Junfeng Liu ◽  
Virginija Cvirkaite-Krupovic ◽  
Diana P. Baquero ◽  
Yunfeng Yang ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Transcriptional Repression ◽  
Asymmetric Cell Division ◽  
Cell Cycle Control ◽  
Evolutionary Relationship ◽  
Giant Cells ◽  
Endosomal Sorting ◽  
Infected Cells ◽  
Cellular Dna

Archaeal viruses represent one of the most mysterious parts of the global virosphere, with many virus groups sharing no evolutionary relationship to viruses of bacteria or eukaryotes. How these viruses interact with their hosts remains largely unexplored. Here we show that nonlytic lemon-shaped virus STSV2 interferes with the cell cycle control of its host, hyperthermophilic and acidophilic archaeon Sulfolobus islandicus, arresting the cell cycle in the S phase. STSV2 infection leads to transcriptional repression of the cell division machinery, which is homologous to the eukaryotic endosomal sorting complexes required for transport (ESCRT) system. The infected cells grow up to 20-fold larger in size, have 8,000-fold larger volume compared to noninfected cells, and accumulate massive amounts of viral and cellular DNA. Whereas noninfected Sulfolobus cells divide symmetrically by binary fission, the STSV2-infected cells undergo asymmetric division, whereby giant cells release normal-sized cells by budding, resembling the division of budding yeast. Reinfection of the normal-sized cells produces a new generation of giant cells. If the CRISPR-Cas system is present, the giant cells acquire virus-derived spacers and terminate the virus spread, whereas in its absence, the cycle continues, suggesting that CRISPR-Cas is the primary defense system in Sulfolobus against STSV2. Collectively, our results show how an archaeal virus manipulates the cell cycle, transforming the cell into a giant virion-producing factory.

scholarly journals A tensile ring drives tissue flows to shape the gastrulating amniote embryo

Science ◽  
2020 ◽  
Vol 367 (6476) ◽  
pp. 453-458 ◽  
Author(s):  
Mehdi Saadaoui ◽  
Didier Rocancourt ◽  
Julian Roussel ◽  
Francis Corson ◽  
Jerome Gros
Keyword(s):  
Cell Division ◽  
Simple Model ◽  
Large Scale ◽  
Fluid Motion ◽  
Primitive Streak ◽  
Early Embryo ◽  
Tissue Morphogenesis ◽  
Mesoscopic Scale ◽  
Avian Embryos ◽  
Embryonic Disk

Tissue morphogenesis is driven by local cellular deformations that are powered by contractile actomyosin networks. How localized forces are transmitted across tissues to shape them at a mesoscopic scale is still unclear. Analyzing gastrulation in entire avian embryos, we show that it is driven by the graded contraction of a large-scale supracellular actomyosin ring at the margin between the embryonic and extraembryonic territories. The propagation of these forces is enabled by a fluid-like response of the epithelial embryonic disk, which depends on cell division. A simple model of fluid motion entrained by a tensile ring quantitatively captures the vortex-like “polonaise” movements that accompany the formation of the primitive streak. The geometry of the early embryo thus arises from the transmission of active forces generated along its boundary.

scholarly journals The abrogation of condensin function provides independent evidence for defining the self-renewing population of pluripotent stem cells

2017 ◽  
Author(s):  
Alvina G. Lai ◽  
Nobuyoshi Kosaka ◽  
Prasad Abnave ◽  
Sounak Sahu ◽  
A. Aziz Aboobaker
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Division ◽  
Cell Function ◽  
Giant Cells ◽  
The Self ◽  
Stem Cell Population ◽  
Self Renewal ◽  
Independent Evidence

AbstractHeterogeneity of planarian neoblast stem cells has been categorised on the basis of single cell expression analyses and subsequent experiments to demonstrate lineage relationships. Some data suggest that despite gene expression heterogeneity amongst cells in the cell cycle, in fact only one sub-population, known as sigma neoblasts, can self-renew. Without the tools to perform live in vivo lineage analysis, we instead took an alternative approach to provide independent evidence for defining the self-renewing stem cell population. We exploited the role of highly conserved condensin proteins to functionally assay neoblast self-renewal properties. Condensins are involved in forming properly condensed chromosomes to allow cell division to proceed during mitosis, and their abrogation inhibits mitosis and can lead to repeated endoreplication of the genome in cells that make repeated attempts to divide. We find that planarians possess only the condensin I complex, and that this is required for normal stem cell function. Abrogation of condensin function led to rapid stem cell depletion accompanied by the appearance of giant cells with increased DNA content. Using previously discovered markers of heterogeneity we show that enlarged cells are always from the sigma-class of the neoblast population and we never observe evidence for endoreplication for the other neoblast subclasses. Overall, our data establish that condensins are essential for stem cell maintenance and provide independent evidence that only sigma-neoblasts are capable of multiple rounds of cell division and hence self-renewal.

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