nuclear fragmentation Dotaz Zobrazit nápovědu
At present, nuclear condensation and fragmentation have been estimated also using Hoechst probes in fluorescence microscopy and flow cytometry. However, none of the methods used the Hoechst probes for quantitative spectrofluorometric assessment. Therefore, the aim of the present study was to develop a spectrofluorometric assay for detection of nuclear condensation and fragmentation in the intact cells. We used human hepatoma HepG2 and renal HK-2 cells cultured in 96-well plates treated with potent apoptotic inducers (i.e. cisplatin, staurosporine, camptothecin) for 6-48 h. Afterwards, the cells were incubated with Hoechst 33258 (2 µg/mL) and the increase of fluorescence after binding of the dye to DNA was measured. The developed spectrofluorometric assay was capable to detect nuclear changes caused by all tested apoptotic inducers. Then, we compared the outcomes of the spectrofluorometric assay with other methods detecting cell impairment and apoptosis (i.e. WST-1 and glutathione tests, TUNEL, DNA ladder, caspase activity, PARP-1 and JNKs expressions). We found that our developed spectrofluorometric assay provided results of the same sensitivity as the TUNEL assay but with the advantages of being fast processing, low-cost and a high throughput. Because nuclear condensation and fragmentation can be typical markers of cell death, especially in apoptosis, we suppose that the spectrofluorometric assay could become a routinely used method for characterizing cell death processes.
- MeSH
- apoptóza účinky léků MeSH
- bisbenzimidazol chemie MeSH
- buněčná smrt účinky léků MeSH
- buněčné jádro účinky léků metabolismus MeSH
- buněčné linie MeSH
- buňky Hep G2 MeSH
- cisplatina farmakologie MeSH
- fluorescenční mikroskopie metody MeSH
- fluorescenční spektrometrie metody MeSH
- fragmentace DNA účinky léků MeSH
- kamptothecin farmakologie MeSH
- lidé MeSH
- protinádorové látky farmakologie MeSH
- průtoková cytometrie metody MeSH
- reprodukovatelnost výsledků MeSH
- staurosporin farmakologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- bisbenzimidazol MeSH
- cisplatina MeSH
- kamptothecin MeSH
- protinádorové látky MeSH
- staurosporin MeSH
The great complexity of extracellular freezing stress, involving mechanical, osmotic, dehydration and chemical perturbations of the cellular milieu, hampers progress in understanding the nature of freezing injury and the mechanisms to cope with it in naturally freeze-tolerant insects. Here, we show that nuclear DNA fragmentation begins to occur in larval haemocytes of two fly species, Chymomyza costata and Drosophila melanogaster, before or at the same time as the sub-zero temperature is reached that causes irreparable freezing injury and mortality in freeze-sensitive larval phenotypes. However, when larvae of the freeze-tolerant phenotype (diapausing-cold acclimated-hyperprolinemic) of C. costata were subjected to severe freezing stress in liquid nitrogen, no DNA damage was observed. Artificially increasing the proline concentration in freeze-sensitive larvae of both species by feeding them a proline-enriched diet resulted in a decrease in the proportion of nuclei with fragmented DNA during freezing stress. Our results suggest that proline accumulated in diapausing C. costata larvae during cold acclimation may contribute to the protection of nuclear DNA against fragmentation associated with freezing stress.
- Klíčová slova
- Comet assay, DNA fragmentation, Freeze tolerance, Insects, Proline,
- MeSH
- aklimatizace MeSH
- Drosophila melanogaster * MeSH
- hmyz * MeSH
- larva MeSH
- nízká teplota MeSH
- prolin MeSH
- zmrazování MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- prolin MeSH
PURPOSE: In carbon ion beam radiation therapy, fragmentation processes within the patient lead to changes in the composition of the particle field with increasing depth. Consequences are alterations of the resulting dose distribution and its biological effectiveness. To enable accurate treatment planning, the characteristics of the ion spectra resulting from fragmentation processes need to be known for various ion energies and target materials. In this work, we present a novel method for ion type identification using a small and highly flexible setup based on a single detector and designed to simplify measurements and overcome current shortages in available fragmentation data. MATERIALS AND METHODS: The presented approach is based on the pixelated, semiconductor detector Timepix. The large number of pixels with small pitch, all individually calibrated for energy deposition, enables detection and visualization of single particle tracks. For discrimination among different ion species, the pattern recognition analysis of the detector signal is used. Fragmentation spectra resulting from a primary carbon ion beam at various depths of tissue-equivalent material were studied to identify different ion species in mixed particle fields. The performance of the method was evaluated quantitatively using reference data from an established technique. RESULTS: All ion species resulting from carbon ion fragmentation in tissue-equivalent material could be separated. For measurements behind a 158-mm-thick water tank, the relative fractions of H, He, Be, and B ions detected agreed with corresponding reference data within the limits of uncertainty. For the relatively rare lithium ions, the agreement was within 2.3 Δref (uncertainty of reference). CONCLUSION: For designated configurations, the presented ion type identification method enables studies of therapeutic carbon ion beams with a simple, small, and configurable detection setup. The technique is promising to enable online fragmentation studies over a wide range of beam and target parameters in the future.
- Klíčová slova
- carbon ion beam therapy, detector Timepix, ion type identification, nuclear fragmentation, pattern recognition analysis, pixel,
- Publikační typ
- časopisecké články MeSH
Cellular senescence, induced by genotoxic or replication stress, is accompanied by defects in nuclear morphology and nuclear membrane-heterochromatin disruption. In this work, we analyzed cytological and molecular changes in the linker of nucleoskeleton and cytoskeleton (LINC) complex proteins in senescence triggered by γ-irradiation. We used human mammary carcinoma and osteosarcoma cell lines, both original and shRNA knockdown clones targeting lamin B receptor (LBR) and leading to LBR and lamin B (LB1) reduction. The expression status and integrity of LINC complex proteins (nesprin-1, SUN1, SUN2), lamin A/C, and emerin were analyzed by immunodetection using confocal microscopy and Western blot. The results show frequent mislocalization of these proteins from the nuclear membrane to cytoplasm and micronuclei and, in some cases, their fragmentation and amplification. The timing of these changes clearly preceded the onset of senescence. The LBR deficiency triggered neither senescence nor changes in the LINC protein distribution before irradiation. However, the cytological changes following irradiation were more pronounced in shRNA knockdown cells compared to original cell lines. We conclude that mislocalization of LINC complex proteins is a significant characteristic of cellular senescence phenotypes and may influence complex events at the nuclear membrane, including trafficking and heterochromatin attachment.
- Klíčová slova
- LINC complex proteins, SUN1/2, heterochromatin-nuclear membrane disconnection, lamin B receptor, nesprin-1, γ-irradiation,
- MeSH
- časoprostorová analýza MeSH
- jaderný obal metabolismus MeSH
- lidé MeSH
- membránové proteiny metabolismus MeSH
- receptor laminu B MeSH
- receptory cytoplazmatické a nukleární genetika MeSH
- stárnutí buněk genetika MeSH
- záření gama terapeutické užití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- membránové proteiny MeSH
- receptory cytoplazmatické a nukleární MeSH
Nuclear transfer experiments in mammals have attempted to reprogram a donor nucleus to a state equivalent to the zygotic one. Reprogramming of the donor nucleus is, among other features, indicated by a synthesis of ribosomal RNA (rRNA). The initiation of rRNA synthesis is simultaneously reflected in nuclear morphology as a transformation of the nucleolus precursor body into a functional rRNA synthesising nucleolus with a characteristic ultrastructure. We examined nucleolar ultrastructure in bovine in vitro produced (control) embryos and in nuclear transfer embryos reconstructed from a MII phase (nonactivated) or S phase (activated) cytoplasts. Control embryos were fixed at the two-, four-, early eight- and late eight-cell stages; nuclear transfer embryos were fixed at 1 and 3 hr post fusion and at the two-, four-, and eight-cell stages. Control embryos possessed a nucleolar precursor body throughout all three cell cycles. In the eight-cell stage embryo, a primary vacuole appeared as an electron lucid area originating in the centre of the nucleolar precursor body. In nuclear transfer embryos reconstructed from nonactivated cytoplasts, the nuclear envelope was fragmented or completely broken down at 1 hr after fusion and, by 3 hr after fusion, it was restored again. At this time, the reticulated fibrillo-granular nucleolus had an almost round shape. The nucleolar precursor body seen in the two-cell stage nuclear transfer embryos consisted of intermingled filamentous components and secondary vacuoles. A nucleolar precursor body typical for the two-cell stage control embryos was never observed. None of the reconstructed embryos of this group reached the eight-cell stage. Nuclear transfer embryos reconstructed from activated cytoplasts, in contrast, exhibited a complete nuclear envelope at all time intervals after fusion. In the two-cell stage nuclear transfer embryo, the originally reticulated nucleolus of the donor blastomere had changed into a typical nucleolar precursor body consisting of a homogeneous fibrillar structure. A primary vacuole appeared in the four-cell stage nuclear transfer embryos, which was one cell cycle earlier than in control embryos. Only nuclear transfer embryos reconstructed from activated cytoplasts underwent complete remodelling of the nucleolus. The reorganisation of the donor nucleolar architecture into a functionally active nucleolus was observed as early as in the four-cell stage nuclear transfer embryo. These ultrastructural observations were correlated with our autoradiographic data on the initiation of RNA synthesis in nuclear transfer embryos.
The level of the Epstein-Barr virus (EBV)-determined nuclear antigen (EBNA-1) encoded by the Bam HI-K fragment of EBV DNA remained unchanged in P3HR-1 cells after induction of the productive cycle of virus replication by sodium-n-butyrate and 12-o-tetradecanoylphorbol-13-acetate (TPA). This was shown by the same capacity of cell-free extracts from untreated and treated P3HR-1 cells to absorb anti-EBNA-1 antibody from a known human serum.
- MeSH
- antigeny virové analýza genetika MeSH
- DNA virů genetika MeSH
- lidé MeSH
- nádorové buňky kultivované imunologie mikrobiologie MeSH
- replikace viru * MeSH
- virus Epsteinův-Barrové - jaderné antigeny MeSH
- virus Epsteinův-Barrové genetika imunologie fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- antigeny virové MeSH
- DNA virů MeSH
- virus Epsteinův-Barrové - jaderné antigeny MeSH
Somatic cell nuclear transfer (SCNT) is a very promising cloning technique for reconstruction of endangered animals. The aim of the present research is to implement the interspecific SCNT (iSCNT) technique to sturgeon; one fish family bearing some of the most critically endangered species. We transplanted single cells enzymatically isolated from a dissociated fin-fragment of the Russian sturgeon (Acipenser gueldenstaedtii) into non-enucleated eggs of the sterlet (Acipenser ruthenus), two species bearing different ploidy (4n and 2n, respectively). Up to 6.7% of the transplanted eggs underwent early development, and one feeding larva (0.5%) was successfully produced. Interestingly, although this transplant displayed tetraploidism (4n) as the donor species, the microsatellite and species-specific analysis showed recipient-exclusive homozygosis without any donor markers. Namely, with regards to this viable larva, host genome duplication occurred twice to form tetraploidism during its early development, probably due to iSCNT manipulation. The importance of this first attempt is to apply iSCNT in sturgeon species, establishing the crucial first steps by adjusting the cloning-methodology in sturgeon's biology. Future improvements in sturgeon's cloning are necessary for providing with great hope in sturgeon's reproduction.
- MeSH
- druhová specificita MeSH
- genotyp MeSH
- haploidie MeSH
- homozygot MeSH
- klonování organismů metody MeSH
- mikrosatelitní repetice MeSH
- ohrožené druhy MeSH
- ryby embryologie genetika růst a vývoj MeSH
- techniky jaderného přenosu * MeSH
- tetraploidie MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Geografické názvy
- Rusko MeSH
Plant DNA is often contaminated by chloroplast DNA. The contamination was used here with advantage to check restriction endonuclease cleavage of plant DNA. This method is based on hybridization of Southern blots of digested plant DNA with cloned fragments of chloroplast DNA as a probe. Advantages of this method are demonstrated.
We applied the nuclear DNA Diffusion Assay, described as an accurate tool to estimate apoptotic and necrotic cells [N.P. Singh, A simple method for accurate estimation of apoptotic cells, Exp. Cell Res. 256 (2000) 328-337] to tobacco root and leaf cells. In this assay, isolated nuclei are embedded in an agarose microgel on a microscope slide and low molecular-weight DNA fragments diffuse into the microgel. Exposure of the roots to hydrogen peroxide significantly increased the average nuclear area of isolated nuclei. After 4 and 24 h of recovery, all DNA damage was repaired. The data clearly demonstrate that the manifestation of diffused nuclei upon exposure to hydrogen peroxide is not the result of non-repairable apoptotic or necrotic DNA fragmentation, but represents repairable genotoxin-induced DNA damage. In contrast, treatment with the alkylating agent ethyl methanesulphonate (EMS) followed by 24 h of recovery produced a significant increase in the average nuclear area. The contribution of apoptosis to this increase cannot be excluded. Heat treatment of leaves at 50 degrees C for 1-15 min leading to necrosis, and treatment of isolated nuclei with DNase-I, which digests DNA to nucleosome-sized fragments as during apoptosis, also led to a dose-dependent increase in the nuclear area. The use of different fluorochromes (ethidium bromide, DAPI or YOYO-1) for DNA staining yielded similar results in the DNA Diffusion Assay. As all types and sizes of diffused nuclei were observed after EMS and hydrogen peroxide treatments, we were unable to differentiate, on the basis of the structure of the nuclei, between apoptotic or necrotic DNA fragmentation and other types of genotoxin-induced DNA damage in plants.
- MeSH
- apoptóza * MeSH
- buněčné jádro účinky léků ultrastruktura MeSH
- deoxyribonukleasa I farmakologie MeSH
- DNA rostlinná účinky léků MeSH
- DNA účinky léků MeSH
- ethylmethansulfonát toxicita MeSH
- kořeny rostlin účinky léků genetika MeSH
- listy rostlin účinky léků genetika MeSH
- mutageny toxicita MeSH
- nekróza * MeSH
- poškození DNA * MeSH
- tabák účinky léků genetika MeSH
- testy genotoxicity metody MeSH
- voda farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- hodnotící studie MeSH
- práce podpořená grantem MeSH
- srovnávací studie MeSH
- Názvy látek
- deoxyribonukleasa I MeSH
- DNA rostlinná MeSH
- DNA MeSH
- ethylmethansulfonát MeSH
- mutageny MeSH
- voda MeSH
