Search results for "polyploidy"

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…

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…

An updated catalogue of chromosome numbers in the genus Isoetes L. (Isoetaceae, Lycopodiophyta)

2010

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 …

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.

Past climate changes facilitated homoploid speciation in three mountain spiny fescues (Festuca, Poaceae)

2016

Apart from the overwhelming cases of allopolyploidization, the impact of speciation through homoploid hybridization is becoming more relevant than previously thought. Much less is known, however, about the impact of climate changes as a driven factor of speciation. To investigate these issues, we selected Festuca picoeuropeana, an hypothetical natural hybrid between the diploid species F. eskia and F. gautieri that occurs in two different mountain ranges (Cantabrian Mountains and Pyrenees) separated by more than 400 km. To unravel the outcomes of this mode of speciation and the impact of climate during speciation we used a multidisciplinary approach combining genome size and chromosome coun…

Autotetraploid Emergence via Somatic Embryogenesis in Vitis vinifera Induces Marked Morphological Changes in Shoots, Mature Leaves, and Stomata

2021

Polyploidy plays an important role in plant adaptation to biotic and abiotic stresses. Alterations of the ploidy in grapevine plants regenerated via somatic embryogenesis (SE) may provide a source of genetic variability useful for the improvement of agronomic characteristics of crops. In the grapevine, the SE induction process may cause ploidy changes without alterations in DNA profile. In the present research, tetraploid plants were observed for 9.3% of ‘Frappato’ grapevine somatic embryos regenerated in medium supplemented with the growth regulators β-naphthoxyacetic acid (10 µM) and N6-benzylaminopurine (4.4 µM). Autotetraploid plants regenerated via SE without detectable changes in the …

Impact of endopolyploidy on seed coat development and cell expansion in Medicago truncatula

2013

Growth of the seed coat is regulated by genetic interactions between maternal and filial tissues that ultimately establish seed size. However, endopolyploidy is one of the welldocumented factors controlling organ size. During seed development, the arrest of cell division at 4 DAP in the expanding seed coat is compensated for by cell elongation. Thus, the ploidy status of seed coat nuclei was assessed in order to determine if there is any correlation of endopolyploidy with cell elongation. In 10 DAP seed sections, the DAPI-integrated fluorescence, which correlates to DNA quantity, was measured in the seed coat parenchyma nuclei using the diploid embryo nuclei as internal control. Significant…

High and uneven levels of 45S rDNA site-number variation across wild populations of a diploid plant genus (Anacyclus, Asteraceae)

2017

The nuclear genome harbours hundreds to several thousand copies of ribosomal DNA. Despite their essential role in cellular ribogenesis few studies have addressed intrapopulation, interpopulation and interspecific levels of rDNA variability in wild plants. Some studies have assessed the extent of rDNA variation at the sequence and copy-number level with large sampling in several species. However, comparable studies on rDNA site number variation in plants, assessed with extensive hierarchical sampling at several levels (individuals, populations, species) are lacking. In exploring the possible causes for ribosomal loci dynamism, we have used the diploid genus Anacyclus (Asteraceae) as a suitab…

Factors influencing survival after resection of pancreatic cancer. A DNA analysis and a histomorphologic study

1994

BACKGROUND The influence of DNA content on prognosis in stomach cancer has been investigated rarely, and the results are controversial. METHOD The prognostic relevance of the DNA content and histomorphologic parameters was evaluated in 41 patients after resection of pancreatic cancer. RESULTS In the univariate analysis, the DNA content, tumor size, lymph node status, tumor stage, nuclear grade, and type of resection had a statistically significant influence on the prognosis. No association was found between the DNA content and the histomorphologic features. Apart from the operative procedure, the DNA content was the strongest indicator of prognosis in the multivariate analysis. CONCLUSIONS …