Search results for "Ploidy"

Somatic embryogenesis and flow cytometric assessment of nuclear genetic stability for Sansevieria spp.: an approach for in vitro regeneration of orna…

2023

Sansevieria Thunb. species are traditionally known as succulent ornamental plants worldwide. They are also cultivated for medicinal, fodder, soil conservation and fiber uses, and for their capacity to reduce environmental pollution. Sansevieria sexual propagation is limited by the lack of viable seeds, and reproduction is largely made via vegetative propagation by suckers or cuttings. For these reasons, genetic improvement by conventional breeding is limited. To overcome this problem and to address the increasing demand from customers for novel Sansevieria varieties, many commercial companies regularly use in vitro propagation, as is the case in the breeding process of several ornamental pl…

Anther culture in Citrus clementina: a way to regenerate tri-haploids

2005

Abstract. Regenerants from anther culture of Citrus clementina Hort. ex Tan. cvv. Nules, SRA 63, and Monreal were obtained in different experiments from 1994 to 2002. Genetic analysis of 37 such regenerants was carried out using 4 microsatellite markers that were heterozygous in the parental genotypes. The results showed that in all cases but one the regenerants carried only one or the other allele of the parental genotype, and were therefore homozygous and produced through a process of gametophytic embryogenesis. Ploidy analysis by flow cytometry of 94 regenerants showed that as many as 82% of them were tri-haploids, rather than haploids or doubled-haploids as expected, with other ploidy …

Comparative genomics among Saccharomyces cerevisiae x Saccharomyces kudriavzevii natural hybrid strains isolated from wine and beer reveals different…

2012

Abstract Background Interspecific hybrids between S. cerevisiae × S. kudriavzevii have frequently been detected in wine and beer fermentations. Significant physiological differences among parental and hybrid strains under different stress conditions have been evidenced. In this study, we used comparative genome hybridization analysis to evaluate the genome composition of different S. cerevisiae × S. kudriavzevii natural hybrids isolated from wine and beer fermentations to infer their evolutionary origins and to figure out the potential role of common S. kudriavzevii gene fraction present in these hybrids. Results Comparative genomic hybridization (CGH) and ploidy analyses carried out in thi…

Aneiploīdija, dzimumhromosomu izmaiņas un mejotisko gēnu ekspresija vīriešu ļaundabīgajos audzējos: Iespējamā mejotiskā izcelsme

2017

Novērots, ka vairākos vēža tipos DNS sadalījums para-triploīdajā diapazonā (ap 69 hromosomām) ir bieži saistīts ar lielāku ļaundabīgumu, paaugstinātu rezistenci pret ķīmijterapiju un nelabvēlīgu prognozi pacientam. Šobrīd vadošā teorija uzskata, ka triploīdās vēža šūnas veidojas no tetraploīdajām nejaušo anomālo mitožu sērijas rezultātā. Tomēr jaunākie novērojumi liecina, ka triploīdijas rašanās var nebūt pilnīgi nejauša un ka tā varētu būt iesaistīta vēža attīstības svarīgākajās stadijās. Sakarā ar jaunākajiem novērojumiem par to, kādu lomu spēlē vēža cilmes šūnas audzēju pašatjaunošanās procesā, zinātnieki sāka atkārtoti pievērsties 19. gadsimta teorijai, kura uzskata, ka vēža šūnu evolūc…

Bisphenol A Effects on the Growing Mouse Oocyte Are Influenced by Diet1

2009

Growing evidence suggests that exposure to bisphenol A (BPA) has the ability to disrupt several different stages of oocyte development. To date, most attention has focused on the effects of BPA on the periovulatory oocyte, and considerable variation is evident in the results of these studies. In our own laboratory, variation in the results of BPA studies conducted at different times appeared to correlate with changes in mill dates of animal feed. This observation, coupled with reports by others that dietary estrogens in feed are a confounding variable in studies of endocrine-disrupting chemicals, prompted us to evaluate the effect of diet on the results of BPA studies of the periovulatory o…

Does the evidence matter in medicine? The retinoblastoma paradigm.

2007

Retinoblastoma (Rb) is the most common intraocular malignant tumour in childhood, with an incidence of 1 in 15,000 live births. Complete information on this rare tumour can be easily accessed through the internet, although many aspect concerning the aetiology and pathogenesis of the disease, are still controversial. The "two hit" theory, formulated in 1971 to explain the variegated clinical expression of the disease, is based on the idea that single gene mutation may determine the development of cancer. However, this view does not take into account the most recent evidences showing the role of aneuploidy and chromosome instability in cancer. Also, a number of other genes and epigenetic mech…

Evolution and ecological aspects of parthenogenetic and sexual bagworm moths (Lepidoptera: Psychidae: Naryciinae)

2012

Seasonal feeding strategies of subarctic zooplankton

2012

TP53 mutations and S-phase fraction but not DNA-ploidy are independent prognostic indicators in laryngeal squamous cell carcinoma

2005

To prospectively evaluate the prognostic significance of TP53, H-, K-, and N-Ras mutations, DNA-ploidy and S-phase fraction (SPF) in patients affected by locally advanced laryngeal squamous cell carcinoma (LSCC). Eight-one patients (median follow-up was 71 months) who underwent resective surgery for primary operable locally advanced LSCC were analyzed. Tumor DNA was screened for mutational analysis by PCR/SSCP and sequencing. DNA-ploidy and SPF were performed by flow cytometric analyses. Thirty-six patients (44%) had, at least, a mutation in the TP53 gene. Of them, 22% (8/36) had double mutations and 3% (1/36) had triple mutations. In total, 46 TP53 mutations were observed. The majority (41…