Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
enabled [disable] Abstract
Number of results

Results found: 4

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  DNA METHYLATION
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
EN
Cryopreservation is important for the long-term conservation of plant genetic resources, especially for the species producing recalcitrant seeds and clonally propagated crops which are proliferated through grafting or as vegetative cuttings, suckers, roots, tubers and bulbs. Despite the fact that in liquid nitrogen temperature the cell division and metabolism are arrested, the factors associated with cryotreatment, cryostorage or plant recovery could be a source of somaclonal variations. The lecture assesses an attempt of attained knowledge within the influence of cryopreservation on the genetic integrity of regenerated plants or recovered tissue. Assessment of genetic and epigenetic stability of the recovered plants derived from cryopreserved plant material is an important step to success of any storage protocol. Until now, from among 64 published papers, only 7 have shown genetic changes in plantlets regenerated after cryopreservation, and 3 - variability in tissue recovered after cryostorage without consequences in regenerants. Epigenetic changes were described using isoschisomers and MSAP, AMP or RAPD methods in 9 works. It was suggested that the processes of cryoprotection and cryostorage had an impact on DNA methylation status, it could lead to alterations in chromatin structure and changes in gene expression. However, majority of the works reported on the insignificant or any influence of cryopreservation on the plant material.
EN
A body of evidence accumulated over the past decade suggests that epigenetic mechanisms play an essential role in maintaining important cellular functions. Changes in epigenetic patterns (mainly DNA hyper- and hypomethylation and, more recently, histone modifications) may contribute to the development of cancer. Aberrant epigenetic events expand thorough tumor progression from the earliest to latest stages, therefore they can serve as convenient markers for detection and prognosis of cancer. The potential reversibility of epigenetic states in the tumor cell is an attractive target for cancer therapy. Much of our current knowledge on epigenetic alternations in cancer comes from studies on gastrointestinal malignancies, mainly on colorectal cancer, which currently serves as a model for epigenetic tumorigenesis. This review summarizes the current knowledge of epigenetic changes in gastrointestinal cancers and how this relates directly to disease progression and prognosis.
EN
Plant genomes are dynamic structures having both the system to maintain and accurately reproduce the information encoded therein and the ability to accept more or less random changes, which is one of the foundations of evolution. Crop improvement and various uncontrolled stress factors can induce unintended genetic and epigenetic variations. In this review it is attempted to summarize factors causing such changes and the molecular nature of these variations in transgenic plants. Unintended effects in transgenic plants can be divided into three main groups: first, pleiotropic effects of integrated DNA on the host plant genome; second, the influence of the integration site and transgene architecture on transgene expression level and stability; and third, the effect of various stresses related to tissue handling, regeneration and clonal propagation. Many of these factors are recently being redefined due to new researches, which apply modern highly sensitive analytical techniques and sequenced model organisms. The ability to inspect large portions of genomes clearly shows that tissue culture contributes to a vast majority of observed genetic and epigenetic changes. Nevertheless, monitoring of thousands transcripts, proteins and metabolites reveals that unintended variation most often falls in the range of natural differences between landraces or varieties. We expect that an increasing amount of evidence on many important crop species will support these observations in the nearest future.
EN
We report on a 13-month-old girl showing dysmorphic features and a delay in psychomotor development. She was diagnosed with a balanced de novo translocation 46,X,t(X;13)(p11.2;p13) and non-random inactivation of the X chromosome. FISH analysis, employing the X chromosome centromere and XIST-region-specific probes, showed that the XIST locus was not involved in the translocation. Selective inactivation of paternal X, which was involved in translocation, was revealed by the HUMARA assay. The pattern of methylation of 5 genes located within Xp, which are normally silenced on an inactive X chromosome, corresponded to an active (unmethylated) X chromosome. These results revealed that in our proband the X chromosome involved in translocation (Xt) was preferentially inactivated. However, genes located on the translocated Xp did not include XIST. This resulted in functional Xp disomy, which most probably accounts for the abnormal phenotype in our patient.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.