scholarly journals Evaluation of mitotic activity in tapetal cells of grapevine (Vitis L.)

2021 ◽  
Vol 49 (2) ◽  
pp. 11975
Author(s):  
Neiva Izabel PIEROZZI ◽  
Mara FERNANDES MOURA
Keyword(s):  
Mitotic Activity ◽  
Meiotic Stage ◽  
Polyploid Cells ◽  
Cytogenetic Studies ◽  
Tapetal Cells ◽  
Diploid Cells ◽  
Chromosome Spreading ◽  
Interesting Alternative ◽  
Large Nucleolus

The knowledge with reference to the grapevine tapetum has been centered on its anatomy/morphology and hardly anything at all is known about its mitotic activity throughout the microsporogenesis. The aim of this study was to ascertain the mitotic activity in tapetal cells of some grapevines (Vitis L.) broadening knowledge about this tissue and simultaneously corroborating the viability of its use as an alternative tissue for further cytogenetic studies. Young buds of 12 grapevine varieties at different meiotic stages were squashed and tapetal cells a prometaphase/metaphase scored in each meiotic stage. Mitotic activity was observed since the beginning of microsporogenesis, where it was more intense, decreasing toward tetrad. Polyploid tapetal cells arose through endomitosis while the microsporogenesis advanced. Two types of polyploid cells were evidenced, those with two or more individualized diploid chromosome groups and those with only one polyploid group. The percentage of diploid cells and of polyploid cells with two or more individualized diploid groups was higher during the first stage of microsporogenesis, though decreasing and giving way to cells with one large polyploid group as microsporogenesis moved toward tetrad. The nucleolus number was scored at interphase at different stages. Two and four nucleoli prevailed in tapetal cells at all stages except at tetrad where one large nucleolus was seen. The results showed that despite of the squashing technique applied, grapevine tapetum has a substantial amount of cells with mitotic activity with a satisfactory chromosome spreading therefore establishing an interesting alternative and promising tissue for later cytomolecular studies.

scholarly journals The expanding implications of polyploidy

2015 ◽  
Vol 209 (4) ◽  
pp. 485-491 ◽  
Author(s):  
Kevin P. Schoenfelder ◽  
Donald T. Fox
Keyword(s):  
Cell Size ◽  
Recent Progress ◽  
Environmental Stresses ◽  
Polyploid Cells ◽  
Diploid Cells ◽  
Metabolic Output

Polyploid cells, which contain more than two genome copies, occur throughout nature. Beyond well-established roles in increasing cell size/metabolic output, polyploidy can also promote nonuniform genome, transcriptome, and metabolome alterations. Polyploidy also frequently confers resistance to environmental stresses not tolerated by diploid cells. Recent progress has begun to unravel how this fascinating phenomenon contributes to normal physiology and disease.

scholarly journals Transcriptome analysis of tetraploid cells identifies cyclin D2 as a facilitator of adaptation to genome doubling in the presence of p53

2016 ◽  
Vol 27 (20) ◽  
pp. 3065-3084 ◽  
Author(s):  
Tamara A. Potapova ◽  
Christopher W. Seidel ◽  
Andrew C. Box ◽  
Giulia Rancati ◽  
Rong Li
Keyword(s):  
Gene Expression ◽  
Transcriptome Analysis ◽  
Cell Cycle Progression ◽  
Target Genes ◽  
Single Cells ◽  
Cyclin D2 ◽  
Genome Doubling ◽  
Polyploid Cells ◽  
Diploid Cells ◽  
P53 Target Genes

Tetraploidization, or genome doubling, is a prominent event in tumorigenesis, primarily because cell division in polyploid cells is error-prone and produces aneuploid cells. This study investigates changes in gene expression evoked in acute and adapted tetraploid cells and their effect on cell-cycle progression. Acute polyploidy was generated by knockdown of the essential regulator of cytokinesis anillin, which resulted in cytokinesis failure and formation of binucleate cells, or by chemical inhibition of Aurora kinases, causing abnormal mitotic exit with formation of single cells with aberrant nuclear morphology. Transcriptome analysis of these acute tetraploid cells revealed common signatures of activation of the tumor-suppressor protein p53. Suppression of proliferation in these cells was dependent on p53 and its transcriptional target, CDK inhibitor p21. Rare proliferating tetraploid cells can emerge from acute polyploid populations. Gene expression analysis of single cell–derived, adapted tetraploid clones showed up-regulation of several p53 target genes and cyclin D2, the activator of CDK4/6/2. Overexpression of cyclin D2 in diploid cells strongly potentiated the ability to proliferate with increased DNA content despite the presence of functional p53. These results indicate that p53-mediated suppression of proliferation of polyploid cells can be averted by increased levels of oncogenes such as cyclin D2, elucidating a possible route for tetraploidy-mediated genomic instability in carcinogenesis.

scholarly journals Polyploidy in the adult Drosophila brain

2019 ◽  
Author(s):  
Shyama Nandakumar ◽  
Olga Grushko ◽  
Laura A. Buttitta
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Protective Role ◽  
Adult Brain ◽  
Exogenous Dna ◽  
Damage Response ◽  
Polyploid Cells ◽  
Drosophila Brain ◽  
Accumulation Of Damage ◽  
Diploid Cells

AbstractLong-lived cells such as terminally differentiated postmitotic neurons and glia must cope with the accumulation of damage over the course of an animal’s lifespan. How long-lived cells deal with ageing-related damage is poorly understood. Here we show that polyploid cells accumulate in the ageing adult fly brain and that polyploidy protects against DNA damage-induced cell death. Multiple types of neurons and glia that are diploid at eclosion, become polyploid with age in the adult Drosophila brain. The optic lobes exhibit the highest levels of polyploidy, associated with an elevated DNA damage response in this brain region with age. Inducing oxidative stress or exogenous DNA damage leads to an earlier onset of polyploidy, and polyploid cells in the adult brain are more resistant to DNA damage-induced cell death than diploid cells. Our results suggest polyploidy may serve a protective role for neurons and glia in ageing Drosophila melanogaster brains.

scholarly journals Polyploidy in the adult Drosophila brain

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Shyama Nandakumar ◽  
Olga Grushko ◽  
Laura A Buttitta
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Protective Role ◽  
Adult Brain ◽  
Exogenous Dna ◽  
Damage Response ◽  
Polyploid Cells ◽  
Drosophila Brain ◽  
Accumulation Of Damage ◽  
Diploid Cells

Long-lived cells such as terminally differentiated postmitotic neurons and glia must cope with the accumulation of damage over the course of an animal’s lifespan. How long-lived cells deal with ageing-related damage is poorly understood. Here we show that polyploid cells accumulate in the adult fly brain and that polyploidy protects against DNA damage-induced cell death. Multiple types of neurons and glia that are diploid at eclosion, become polyploid in the adult Drosophila brain. The optic lobes exhibit the highest levels of polyploidy, associated with an elevated DNA damage response in this brain region. Inducing oxidative stress or exogenous DNA damage leads to an earlier onset of polyploidy, and polyploid cells in the adult brain are more resistant to DNA damage-induced cell death than diploid cells. Our results suggest polyploidy may serve a protective role for neurons and glia in adult Drosophila melanogaster brains.

scholarly journals CYTOGENETIC STUDIES IN NORTH AMERICAN MINNOWS (CYPRINIDAE). IV. SOMATIC POLYPLOIDY IN GILA BICOLOR

1977 ◽  
Vol 19 (4) ◽  
pp. 657-662 ◽  
Author(s):  
John C. Avise ◽  
John R. Gold
Keyword(s):  
North American ◽  
Kidney Tissue ◽  
Single Individual ◽  
Somatic Polyploidy ◽  
Polyploid Cells ◽  
Cytogenetic Studies ◽  
Cytological Mechanism ◽  
In Cells

The kidney tissue of a single individual of the California minnow Gila bicolor (Girard) contained polyploid cells in about 1.7% frequency. Chromosome spreads of triploid, tetraploid, hexaploid, octaploid, and dodecaploid cells were observed and may have arisen through endoreduplication of ancestral diploid and triploid cells. The cytological mechanism producing the triploid cells is unknown. Diplochromosomes were not present. The distribution of ploidy in cells of this individual is not random. In particular, cells having undergone one round of chromosomal increase appear increasingly susceptible to additional rounds of chromosomal gain.

scholarly journals The structure of heterochromatic DNA is altered in polyploid cells of Drosophila melanogaster.

1997 ◽  
Vol 17 (3) ◽  
pp. 1254-1263 ◽  
Author(s):  
R L Glaser ◽  
T J Leach ◽  
S E Ostrowski
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Dna Sequences ◽  
Dna Molecules ◽  
Restriction Fragments ◽  
General Consequence ◽  
Polyploid Cells ◽  
Chromosome Formation ◽  
Chromosome Iii ◽  
Diploid Cells

DNA sequences within heterochromatin are often selectively underrepresented during development of polyploid chromosomes, and DNA molecules of altered structure are predicted to form as a consequence of the underrepresentation process. We have identified heterochromatic DNAs of altered structure within sequences that are underrepresented in polyploid cells of Drosophila melanogaster. Specifically, restriction fragments that extend into centric heterochromatin of the minichromosome Dp(1;f)1187 are shortened in polyploid cells of both the ovary and salivary gland but not in the predominantly diploid cells of the embryo or larval imaginal discs and brains. Shortened DNA molecules were also identified within heterochromatic sequences of chromosome III. These results suggest that the structure of heterochromatic DNA is altered as a general consequence of polyploid chromosome formation and that the shortened molecules identified form as a consequence of heterochromatic underrepresentation. Finally, alteration of heterochromatic DNA structure on Dp(1;f)1187 was not correlated with changes in the variegated expression of the yellow gene located on the minichromosome.

Polysomaty and somatic reduction in Phaseolus coccineus L.

Genome ◽  
1988 ◽  
Vol 30 (5) ◽  
pp. 671-676 ◽  
Author(s):  
A. Cavallini ◽  
R. Cremonini ◽  
G. Cionini ◽  
P. G. Cionini
Keyword(s):  
De Novo ◽  
Root Apex ◽  
Phaseolus Coccineus ◽  
Homologous Chromosomes ◽  
Chromosome Endoreduplication ◽  
Early Embryos ◽  
Pertinent Data ◽  
Polyploid Cells ◽  
Diploid Cells ◽  
Shoot Meristems

By means of karyological, cytophotometric, and autoradiographic analyses it has been shown that, owing to alterations in the DNA synthesis – mitosis sequence, cells with different nuclear conditions are continuously formed de novo and proliferate in Phaseolus coccineus meristems. Besides diploid cells, the following also occur: (i) polyploid cells as the result of chromosome endoreduplication followed by mitosis; (ii) haploid cells as the result of the separation of the two groups of homologous chromosomes in cells that have omitted DNA reduplication; and (iii) since haploid cells undergo chromosome endoreduplication and divide, isogenic cells can be produced. Diploid mitoses alone are present in the meristems of early embryos; haploid mitoses first appear in both root and shoot meristems with increasing embryo development, followed later by cells undergoing chromosome endoreduplication. The study of the root apex has shown that neither polyploid nor reduced cells occur with the same frequency in its various portions. These results are discussed in relation to pertinent data in the literature and the mechanisms responsible for the occurrence of polysomaty and somatic reduction are suggested.Key words: isogenic cells, Phaseolus coccineus, polysomaty, somatic reduction.

THE DEVELOPMENT AND SUPPRESSION OF POLYPLOIDY IN THE DEVELOPING AND SUPPRESSED DECIDUOMA IN THE RAT

1955 ◽  
Vol 12 (2) ◽  
pp. 146-151 ◽  
Author(s):  
LEO SACHS ◽  
M. C. SHELESNYAK
Keyword(s):  
Mitotic Activity ◽  
Histamine Stimulation ◽  
Limited Life ◽  
Decidual Cells ◽  
Polyploid Cells ◽  
Cytological Changes ◽  
Stimulation Of

SUMMARY Pseudopregnant rats were used to study cytological changes in the endometrium following mechanical or chemical (histamine) stimulation of the mucosa. Normal deciduomata, and decidual growths suppressed by topical intra-lumen application of the anti-histamine drug Benadryl, were examined at intervals from 1 to 216 hr after mucosal stimulation. Results showed no mitotic activity in either the normal or suppressed horn for the first 18 hr followed by diploid activity from 18½ to 27 hr. After 27 hr, the suppressed horn showed no more mitoses, and no development of polyploidy; the normal deciduoma showed diploid mitoses for a longer period, and then the development of polyploidy. In the developing deciduoma polyploidy appeared 36 hr after stimulation. There was an increase in the amount of polyploid cells with the continued development of the deciduoma. It is concluded that (a) the suppression of deciduomata by anti-histamine is effected by the suppression of development of the deciduoma and not by a gross destruction of tissue; (b) polyploidy develops in the deciduoma, possibly involving all the decidual cells; (c) the extensive existence of polyploid cells which cannot reproduce normally or persist is a possible basis for the limited life of the deciduoma.

Homologous chromosome pairing in wheat

1999 ◽  
Vol 112 (11) ◽  
pp. 1761-1769 ◽  
Author(s):  
E. Martinez-Perez ◽  
P. Shaw ◽  
S. Reader ◽  
L. Aragon-Alcaide ◽  
T. Miller ◽  
...  
Keyword(s):  
Chromosome Pairing ◽  
Meiotic Prophase ◽  
Homologous Chromosome ◽  
Wild Type ◽  
Sister Chromatids ◽  
Homologous Chromosome Pairing ◽  
Tapetal Cells ◽  
Telomere Cluster ◽  
Diploid Cells ◽  
Degree Of Association

Bread wheat is a hexaploid (AABBDD, 2n=6x=42) containing three related ancestral genomes, each having 7 chromosomes, giving 42 chromosomes in diploid cells. During meiosis true homologues are correctly associated in wild-type wheat, but a degree of association of related chromosomes (homoeologues) occurs in a mutant (ph1b). We show that the centromeres are associated in non-homologous pairs in all floral tissues studied, both in wild-type wheat and the ph1b mutant. The non-homologous centromere associations then become homologous premeiotically in wild-type wheat in both meiocytes and the tapetal cells, but not in the mutant. In wild-type wheat, the homologues are colocalised along their length at this stage, but the telomeres remain distinct. A single telomere cluster (bouquet) is formed in the meiocytes only by the onset of leptotene. The sub-telomeric regions of the homologues associate as the telomere cluster forms. The homologous associations at the telomeres and centromeres are maintained through meiotic prophase, although, during leptotene, the two homologues and also the sister chromatids within each homologue are separate along the rest of their length. As meiosis progresses, first the sister chromatids and then the homologues associate intimately. In wild-type wheat, first the centromere grouping, then the bouquet disperse by the end of zygotene.

scholarly journals Metabolism-Induced Oxidative Stress and DNA Damage Selectively Trigger Genome Instability in Polyploid Cells

2018 ◽  
Author(s):  
Gregory J. Thomson ◽  
Claire Hernon ◽  
O.P. Nicanor Austriaco ◽  
Rebecca S. Shapiro ◽  
Peter Belenky ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Genome Stability ◽  
Metabolic Flux ◽  
Genome Instability ◽  
Chromosome Instability ◽  
Sporulation Medium ◽  
Pathogenic Yeast ◽  
Polyploid Cells ◽  
Diploid Cells

AbstractUnderstanding the forces impacting genome stability is important for diverse processes such as tumorigenesis and reproductive biology. The pathogenic yeastCandida albicansdisplays unusual genome dynamics in which tetraploid cells, but not diploid cells, become unstable when grown on a glucose-rich ‘pre-sporulation’ medium. Here, we reveal thatC. albicanspolyploid cells are metabolically hyperactive on this medium as evidenced by increased expression of metabolic genes as well as higher rates of fermentation and oxidative respiration. These cells also show elevated levels of reactive oxygen species (ROS), activate the ROS-responsive transcription factor Cap1, and accrue DNA double-strand breaks. Suppression of ROS levels reduced oxidative stress, DNA damage and chromosome instability. These studies reveal how metabolic flux can generate endogenous ROS, triggering DNA damage and genome instability in polyploid, but not diploid, cells. We discuss parallels with metabolism-induced instability in cancer cells and propose that ROS-induced DNA damage could have facilitated ploidy cycling in eukaryotes prior to the evolution of meiosis.

Sign in / Sign up

Export Citation Format

Share Document