Search results for "Polyploid"
showing 10 items of 59 documents
Activation of self-renewal and meiotic genes in tumour cell lines resistant to genotoxic treatment
2014
Pašatjaunošanās un meijotisko gēnu aktivācija pēc genotoksiskas apstrādes rezistentās audzēju šūnu līnijās Šajā darbā tika pētīta iespējamā saistība starp poliploīdijas un dzimumšūnu līnijai raksturīgo gēnu indukciju pēc pretvēža apstrādes atkarībā no TP53 statusa un audzēju šūnu rezistence pret DNS bojājumu. Pirmo reizi tika atrasta un citoloģiski raksturota galveno cilmestības transkripcijas faktoru OCT4, NANOG un SOX2 ekspresijas aktivācija, kas izraisīta pārkāpjot tetraploīdo barjeru pēc DNS bojājuma TP53 mutantās, bet ne funkcionālās audzēja šūnas, kā arī galvenā mejotiskā kohezīna REC8 ekspresija somatisko audzēja šūnu līnijās, kas apstrādātas ar jonizējošo starojumu vai topoizomeraze…
ENDOPOLYPLOIDY OF ENDANGERED PLANT SPECIES LIGULARIA SIBIRICA IN DIFFERENT ENVIRONMENTS
2017
The goal of this study was to detect endopolyploidy of Ligularia sibirica from populations existed in different ecological conditions. This is important step to elaborate the appropriate protection measures of rare and endangered species, which should be based on understanding of ongoing processes in populations. From this point of view the knowledge of genetic diversity, including endopolyploidy level between and within populations, is crucial. L. sibirica is endangered and protected plant species in Latvia which is included in the protected plants list of EU Habitat directive 92/43/EEK Annexes 2 and 4. Perennial herbaceous plant L. sibirica is one of two species of genus Ligularia in Euro…
The geography of hybrid speciation in plants
2015
Nuclear DNA content variation inHalimiumandXolantha(Cistaceae)
2008
Abstract Chromosome numbers and nuclear DNA contents were determined in several taxa of two genera of Cistaceae, Halimium and Xolantha. The diploid chromosome number 2n = 18 is stable within the genus Halimium. In Xolantha, the diploid chromosome number 2n = 14 was confirmed in X. tuberaria, and hexaploid (2n = 36) and octoploid (2n = 48) cytotypes were found in X. guttata. DNA amounts, first reported here for these genera, were determined by flow cytometry of propidium iodide-stained nuclei. Within Halimium there is a more than twofold difference in genome size between H. calycinum (7.61 pg DNA) and H. atriplicifolium (3.66 pg DNA). Within the genus Xolantha, absolute genome sizes of 7.3 a…
“Mitotic Slippage” and Extranuclear DNA in Cancer Chemoresistance: A Focus on Telomeres
2020
Mitotic slippage (MS), the incomplete mitosis that results in a doubled genome in interphase, is a typical response of TP53-mutant tumors resistant to genotoxic therapy. These polyploidized cells display premature senescence and sort the damaged DNA into the cytoplasm. In this study, we explored MS in the MDA-MB-231 cell line treated with doxorubicin (DOX). We found selective release into the cytoplasm of telomere fragments enriched in telomerase reverse transcriptase (hTERT), telomere capping protein TRF2, and DNA double-strand breaks marked by γH2AX, in association with ubiquitin-binding protein SQSTM1/p62. This occurs along with the alternative lengthening of telomeres (ALT) and DNA repa…
Karyological data of three Hieracium (Asteraceae) from Sicily and South Italy
2021
Chromosome numbers are given for three endemic Hieracium taxa from Sicily and Campania (Southern Italy). All the examined taxa resulted triploid (2n = 3x = 27). The triploid chromosome set found in the population of H. pallidum from Rocche dell’Argimusco (Peloritani Mountains, NE-Sicily) differs from the previous counts (2n = 4x = 36) reported for the same species from its locus classicus (Mt. Etna).
Conditions in Home and Transplant Soils Have Differential Effects on the Performance of Diploid and Allotetraploid Anthericum Species
2015
Due to increased levels of heterozygosity, polyploids are expected to have a greater ability to adapt to different environments than their diploid ancestors. While this theoretical pattern has been suggested repeatedly, studies comparing adaptability to changing conditions in diploids and polyploids are rare. The aim of the study was to determine the importance of environmental conditions of origin as well as target conditions on performance of two Anthericum species, allotetraploid A. liliago and diploid A. ramosum and to explore whether the two species differ in the ability to adapt to these environmental conditions. Specifically, we performed a common garden experiment using soil from 6 …
p27Kip1participates in the regulation of endoreplication in differentiating chick retinal ganglion cells
2015
Nuclear DNA duplication in the absence of cell division (i.e. endoreplication) leads to somatic polyploidy in eukaryotic cells. In contrast to some invertebrate neurons, whose nuclei may contain up to 200,000-fold the normal haploid DNA amount (C), polyploid neurons in higher vertebrates show only 4C DNA content. To explore the mechanism that prevents extra rounds of DNA synthesis in these latter cells we focused on the chick retina, where a population of tetraploid retinal ganglion cells (RGCs) has been described. We show that differentiating chick RGCs that express the neurotrophic receptors p75 and TrkB while lacking retinoblastoma protein, a feature of tetraploid RGCs, also express p27K…
Near-Haploidy in a Malignant Sacrococcygeal Teratoma
1999
Cytogenetic analysis of a malignant sacrococcygeal teratoma in an adult patient revealed near-haploid (77%), near-diploid (19%), and polyploid (4%) cells. The near-haploid cells had a karyotype of 25,XX,der(5)t(5;7)(p15;p13),+7,der(9)t(6;9)(p21;q34),r(17)(p13q25) . In the near-diploid and polyploid cells identical copies of the structural chromosomal changes were found. Although some of the anomalies observed appear unique to this case, a common breakpoint in chromosome 6 was previously reported as specific in a subgroup of extragonadal germ cell tumors of adults.