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Wyszukujesz frazę "DNA double-strand breaks" wg kryterium: Temat


Wyświetlanie 1-5 z 5
Tytuł:
Metoda znajdowania komórek i zliczania ognisk występowania histonu γ-H2AX w obrazach na potrzeby detekcji dwuniciowych pęknięć DNA
Method for cell finding and histone γ-H2AX foci counting in images for detecting DNA double-strand breaks
Autorzy:
Wojciechowski, P.
Bal, A.
Powiązania:
https://bibliotekanauki.pl/articles/154831.pdf
Data publikacji:
2012
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
γ-H2AX
dwuniciowe pęknięcia DNA
przetwarzanie obrazów
obrazy biomedyczne
segmentacja wododziałowa
double-strand breaks (DSB)
image processing
biomedical images
watershed segmentation
Opis:
Niniejsza praca opisuje algorytm automatyzujący proces zliczania ognisk histonu γ-H2AX w obrazach mikroskopowych. Ogniska te są miejscami, w których doszło do fosforylacji białka histonu H2AX w pozycji seryny 139 wskutek dwuniciowych pęknięć DNA. Propono-wana metoda działa dwuetapowo. Najpierw w obrazie mikroskopowym selekcjonowane są obiekty uznawane za komórki, a następnie na obszarze tych obiektów poszukiwane są miejsca wyznakowane barwnikiem fluorescencyjnym związanym z przeciwciałem anty-γ-H2AX - miejsca te wskazują na lokalizację ognisk γ-H2AX.
This paper describes an algorithm for automating the process of counting foci of histone γ-H2AX in microscope images. Foci are the places where there occurred H2AX protein phosphorylation on Ser139 site in response to DNA double-strand breaks (DSBs). In a γ-H2AX genotoxic test the number of foci per a single cell is counted. The proposed method works in two stages. The first stage is segmentation of a microscopic image (Fig. 1a) for selecting cell regions. For this purpose fusion of binarization methods is used - for the each pixel the result is obtained by comparison of the results from the Otsu method, the triangle method and the method in which the threshold is equal to the image average brightness. The pixel is classified as an object's pixel when at least two methods give such results. For improving segmentation results a morphological filter is used. The results (Fig. 1b) usually comprise regions representing single cells (Fig. 1c) and a set of agglomerated cells (Fig. 1d). A modified watershed segmentation and region classify method is used for separation of agglomerated cells into regions representing only one cell. The final result (Fig.1e) contains only regions representing single cells. In the second stage for each single cell region the foci (which are marked with a fluorescent indicator joined with anti- γ-H2AX antibody) are found (Fig. 3) with use of watershed segmentation on the pseudogradient image (which is obtained by aggregation of the results of cell image binarization with different thresholds; Fig. 2). The final results in form of foci number as a function of time after irradiation (Fig. 4) are similar to the test results of non-lethal DNA damages founded in the literature (e.g. [5]) - this allows stating that the presented method gives good results.
Źródło:
Pomiary Automatyka Kontrola; 2012, R. 58, nr 4, 4; 387-390
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intranuclear trafficking of plasmid DNA is mediated by nuclear polymeric proteins lamins and actin
Autorzy:
Ondřej, Vladan
Lukášová, Emilie
Krejčí, Jana
Kozubek, Stanislav
Powiązania:
https://bibliotekanauki.pl/articles/1040744.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
plasmid DNA
DNA double-strand breaks
nuclear actin
lamin A/C
Opis:
Functions of nuclear polymeric proteins such as lamin A/C and actin in transport of plasmid DNA were studied. The results show that the lamina plays an important role in plasmid DNA's entry into the cell nucleus from the cytoplasm. Selective disruption of lamin A/C led to a halt in plasmid DNA transport through the nuclear envelope. Inside the nucleus, plasmid DNA was frequently localized at sites with impaired genome integrity, such as DNA double-strand breaks (DSBs), occurring spontaneously or induced by ionizing radiation. Polymeric actin obviously participates in nuclear transport of plasmid DNA, since inhibition of actin polymerization by latrunculin B disturbed plasmid transport inside the cell nucleus. In addition, precluding of actin polymerization inhibited plasmid co-localization with newly induced DSBs. These findings indicate the crucial role of polymeric actin in intranuclear plasmid transport.
Źródło:
Acta Biochimica Polonica; 2008, 55, 2; 307-315
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-homologous DNA end joining.
Autorzy:
Pastwa, Elżbieta
Błasiak, Janusz
Powiązania:
https://bibliotekanauki.pl/articles/1043360.pdf
Data publikacji:
2003
Wydawca:
Polskie Towarzystwo Biochemiczne
Tematy:
Ku proteins
DNA-PK
homologous recombination
non-homologous end joining
DSB; DNA repair
DNA ligase IV
DNA double-strand breaks
NHEJ
Opis:
DNA double-strand breaks (DSBs) are a serious threat for the cell and when not repaired or misrepaired can result in mutations or chromosome rearrangements and eventually in cell death. Therefore, cells have evolved a number of pathways to deal with DSB including homologous recombination (HR), single-strand annealing (SSA) and non-homologous end joining (NHEJ). In mammals DSBs are primarily repaired by NHEJ and HR, while HR repair dominates in yeast, but this depends also on the phase of the cell cycle. NHEJ functions in all kinds of cells, from bacteria to man, and depends on the structure of DSB termini. In this process two DNA ends are joined directly, usually with no sequence homology, although in the case of same polarity of the single stranded overhangs in DSBs, regions of microhomology are utilized. The usage of microhomology is common in DNA end-joining of physiological DSBs, such as at the coding ends in V(D)J (variable(diversity) joining) recombination. The main components of the NHEJ system in eukaryotes are the catalytic subunit of DNA protein kinase (DNA-PKcs), which is recruited by DNA Ku protein, a heterodimer of Ku70 and Ku80, as well as XRCC4 protein and DNA ligase IV. A complex of Rad50/Mre11/Xrs2, a family of Sir proteins and probably other yet unidentified proteins can be also involved in this process. NHEJ and HR may play overlapping roles in the repair of DSBs produced in the S phase of the cell cycle or at replication forks. Aside from DNA repair, NHEJ may play a role in many different processes, including the maintenance of telomeres and integration of HIV-1 genome into a host genome, as well as the insertion of pseudogenes and repetitive sequences into the genome of mammalian cells. Inhibition of NHEJ can be exploited in cancer therapy in radio-sensitizing cancer cells. Identification of all key players and fundamental mechanisms underlying NHEJ still requires further research.
Źródło:
Acta Biochimica Polonica; 2003, 50, 4; 891-908
0001-527X
Pojawia się w:
Acta Biochimica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Histone H2AX in DNA repair
Autorzy:
Lewandowska, H.
Szumiel, I.
Powiązania:
https://bibliotekanauki.pl/articles/147030.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
DNA double strand breaks
DNA repair
histone gamma-H2AX
ionising radiation
Opis:
The paper reviews the recent reports on the role of the phosphorylated histone H2AX (gamma-H2AX). The modification of this histone is an important part of the cellular response to the induction of DNA double strand breaks (DSB) by ionising radiation and other DSB-generating factors. In irradiated cell the modification is carried out mainly by ATM (ataxia- -telangiectasia mutated) kinase, the enzyme that starts the alarm signalling upon induction of DSB. gamma-H2AX molecules are formed within 1 3 min after irradiation and form foci at the sites of DSB. This seems to be necessary for the recruitment of repair factors that are later present in foci of damaged nuclei. Modification of a constant percentage of H2AX molecules per DSB takes place, corresponding to chromatin domains of megabase pairs of DNA.
Źródło:
Nukleonika; 2002, 47, 4; 127-131
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modified neutral comet assay for human lymphocytes
Autorzy:
Wojewódzka, M.
Grądzka, I.
Buraczewska, I.
Powiązania:
https://bibliotekanauki.pl/articles/147130.pdf
Data publikacji:
2002
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
DNA double strand breaks
human lymphocyte
neutral comet assay
Opis:
Comet assay under neutral conditions allows the detection of DNA double-strand breaks, considered to be the biologically relevant radiation-induced lesion. In this report we describe modifications of the neutral comet method, which simplify and facilitate its use for estimation of DNA double strand breaks in human lymphocytes irradiated with doses of 60Co gamma-rays (from 10 to 100 Gy). The analysis carried out according to this protocol takes less time than those published so far. Also, the use of lysis at 50°C is avoided; this is important in view of the presence of heat-labile sites in the DNA of irradiated cells, recently reported by Rydberg [12]. The comets have well defined, sharp limits, are suitable for computer image analysis and chromatin of the control cells remains condensed.
Źródło:
Nukleonika; 2002, 47, 1; 1-5
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
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