Although it is well known that chromosomes are non-randomly organized during interphase, it is not completely clear whether higher-order chromatin structure is transmitted from mother to daughter cells. Therefore, we addressed the question of how chromatin is rearranged during interphase and whether heterochromatin pattern is transmitted after mitosis. We additionally tested the similarity of chromatin arrangement in sister interphase nuclei. We noticed a very active cell rotation during interphase, especially when histone hyperacetylation was induced or transcription was inhibited. This natural phenomenon can influence the analysis of nuclear arrangement. Using photoconversion of Dendra2-tagged core histone H4 we showed that the distribution of chromatin in daughter interphase nuclei differed from that in mother cells. Similarly, the nuclear distribution of heterochromatin protein 1β (HP1β) was not completely identical in mother and daughter cells. However, identity between mother and daughter cells was in many cases evidenced by nucleolar composition. Moreover, morphology of nucleoli, HP1β protein, Cajal bodies, chromosome territories, and gene transcripts were identical in sister cell nuclei. We conclude that the arrangement of interphase chromatin is not transmitted through mitosis, but the nuclear pattern is identical in naturally synchronized sister cells. It is also necessary to take into account the possibility that cell rotation and the degree of chromatin condensation during functionally specific cell cycle phases might influence our view of nuclear architecture.

• MeSH
• buněčné jadérko účinky léků   genetika   ultrastruktura   MeSH
• buněčné linie MeSH
• Cajalova tělíska účinky léků   genetika   ultrastruktura   MeSH
• chromozomální proteiny, nehistonové genetika   metabolismus   MeSH
• daktinomycin farmakologie   MeSH
• fluorescenční barviva MeSH
• fluorescenční mikroskopie MeSH
• fotochemické procesy MeSH
• heterochromatin účinky léků   genetika   ultrastruktura   MeSH
• histony genetika   metabolismus   MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory histondeacetylas farmakologie   MeSH
• inhibitory syntézy proteinů farmakologie   MeSH
• interfáze účinky léků   genetika   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• messenger RNA biosyntéza   MeSH
• mitóza účinky léků   genetika   MeSH
• myši MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• CBX1 protein, human MeSH Prohlížeč
• Cbx1 protein, mouse MeSH Prohlížeč
• chromozomální proteiny, nehistonové MeSH
• daktinomycin MeSH
• fluorescenční barviva MeSH
• heterochromatin MeSH
• histony MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory histondeacetylas MeSH
• inhibitory syntézy proteinů MeSH
• kyseliny hydroxamové MeSH
• messenger RNA MeSH
• trichostatin A MeSH Prohlížeč

Methotrexate (MTX) released from bone cement showed a useful local effect in animal models of bone tumours. However, local toxic reactions such as impaired wound healing were observed in areas surrounding the MTX-loaded implant. Therefore, we hypothesised that MTX released from bone cement would have harmful effects on human mesenchymal stem cells (MSC)-one of the basic components of bone marrow and tissue reparatory processes. Moreover, elution of MTX was calculated from implants prepared either with liquid or powdered MTX. During the 28-day incubation, the cement compounded with liquid MTX showed the highest elution rate of the drug. MTX released from pellets produced a significant decrease in proliferation of MSC as a consequence of a blockade of their cell cycle in the S/G2 phase. These findings indicate impairment of stem cell function in marginal areas surrounding the MTX-loaded cement and may help to explain problems with regeneration of tissues in these locations.

Le Methotrexate (MTX) libéré par le ciment acrylique a un effet certain sur les tumeurs osseuses développées sur un modèle animal. Cependant, des réactions toxiques locales telles que défauts de cicatrisation ont été observées à proximité de l’implantation de ce ciment. Nous faisons donc l’hypothèse que le Methotrexate MTX libéré par le ciment a un effet nocif néfaste sur les cellules mésenchyméteuses humaines MSC qui sont l’un des composants de base de la moelle osseuse et des phénomènes de la réparation tissulaire. De plus, la dynamique de pénétration du méthotrexate a été analysée à partir d’implants préparés avec du liquide ou de la poudre de méthotrexate. Au cours des 28 jours d’incubation, le ciment préparé avec du méthotrexate liquide montre un taux important de pénétration de la drogue. Le méthotrexate libéré des billes de ciment entraîne une diminution significative de la prolifération des cellules mésenchyméteuses avec un bloquage cellulaire à la phase S/G2. Ces travaux montrent que la fonction cellulaire est altérée au voisInage du méthotrexate pouvant expliquer les problèmes de régénétration tissulaire.

• MeSH
• buňky kostní dřeně účinky léků   patologie   MeSH
• interfáze účinky léků   MeSH
• kostní cementy chemie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• methotrexát aplikace a dávkování   chemie   MeSH
• mezenchymální kmenové buňky účinky léků   patologie   MeSH
• proliferace buněk účinky léků   MeSH
• protinádorové antimetabolity aplikace a dávkování   chemie   MeSH
• viabilita buněk účinky léků   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kostní cementy MeSH
• methotrexát MeSH
• protinádorové antimetabolity MeSH

The effect of the toxic metal ions, aluminium (Al3+), nickel (Ni2+), and copper (Cu2+), on both the actin and tubulin cytoskeleton of the green alga Spirogyra decimina was studied. Batch cultured cells were grown for different time intervals at concentrations of 10, 15, 40 and 100 microM of aluminium as AlCl3, nickel as NiCl2 and copper as CuSO(4).5H2O. The impact of copper on the morphology of both MTs and AFs was much more prominent than the other two metals. A rapid irreversible depolymerization of cytoskeletal structures occurred, whereas in the presence of aluminium or nickel, changes in the cytoskeleton were slight and reversible to some extent. Nickel changed the orientation of cortical MTs, which turned from a transverse to a skewed or longitudinal direction. Aluminium caused slight depolymerization of the cytoskeleton, which reverted spontaneously to the normal cytoskeletal state (in AlCl3 free nutrient solution). Copper exerted a strong effect on both the MT and AF cytoskeleton, which fragmented and disorganized rapidly. The extent of cytoskeletal damage by copper was dosage and time dependent and AFs were slightly more sensitive than MTs.

• MeSH
• aktiny analýza   MeSH
• časové faktory MeSH
• chemické látky znečišťující vodu toxicita   MeSH
• chlorid hlinitý MeSH
• chloridy toxicita   MeSH
• Chlorophyta cytologie   účinky léků   fyziologie   MeSH
• cytoskelet chemie   účinky léků   MeSH
• interfáze účinky léků   MeSH
• mikrotubuly účinky léků   metabolismus   MeSH
• nikl toxicita   MeSH
• síran měďnatý toxicita   MeSH
• sloučeniny hliníku toxicita   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• aktiny MeSH
• chemické látky znečišťující vodu MeSH
• chlorid hlinitý MeSH
• chloridy MeSH
• nickel chloride MeSH Prohlížeč
• nikl MeSH
• síran měďnatý MeSH
• sloučeniny hliníku MeSH

In human cells ribosomal genes are organized as clusters, NORs, situated on the short arms of acrocentric chromosomes. It was found that essential components of the RNA polymerase I transcription machinery, including UBF, can be detected on some NORs, termed "competent" NORs, during mitosis. The competent NORs are believed to be transcriptionally active during interphase. However, since individual NORs were not observed in the cell nucleus, their interphase status remains unclear. To address this problem, we detected the competent NORs by two commonly used methods, UBF immunofluorescence and silver staining, and combined them with FISH for visualization of rDNA and/or specific chromosomes. We found that the numbers of competent NORs on specific chromosomes were largely conserved in the subsequent cell cycles, with certain NOR-bearing homologues displaying a very stable pattern of competence. Importantly, those and only those NORs that were loaded with UBF incorporated bromo-uridine in metaphase after stimulation with roscovitine and in telophase, suggesting that competent and only competent NORs contain ribosomal genes transcriptionally active during interphase. Applying premature chromosome condensation with calyculin A, we visualized individual NORs in interphase cells, and found the same pattern of competence as observed in the mitotic chromosomes.

• MeSH
• barvení stříbrem MeSH
• buněčný cyklus * účinky léků   MeSH
• genetická transkripce * účinky léků   MeSH
• HeLa buňky MeSH
• hybridizace in situ fluorescenční MeSH
• interfáze účinky léků   MeSH
• karyotypizace MeSH
• lidé MeSH
• lidské chromozomy genetika   MeSH
• metafáze účinky léků   MeSH
• organizátor jadérka účinky léků   genetika   MeSH
• puriny farmakologie   MeSH
• roskovitin MeSH
• telofáze účinky léků   MeSH
• transkripční iniciační komplex Pol1 - proteiny metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• puriny MeSH
• roskovitin MeSH
• transcription factor UBF MeSH Prohlížeč
• transkripční iniciační komplex Pol1 - proteiny MeSH

The effects of the histone deacetylase inhibitors (HDACi) trichostatin A (TSA) and sodium butyrate (NaBt) were studied in A549, HT29 and FHC human cell lines. Global histone hyperacetylation, leading to decondensation of interphase chromatin, was characterized by an increase in H3(K9) and H3(K4) dimethylation and H3(K9) acetylation. The levels of all isoforms of heterochromatin protein, HP1, were reduced after HDAC inhibition. The observed changes in the protein levels were accompanied by changes in their interphase patterns. In control cells, H3(K9) acetylation and H3(K4) dimethylation were substantially reduced to a thin layer at the nuclear periphery, whereas TSA and NaBt caused the peripheral regions to become intensely acetylated at H3(K9) and dimethylated at H3(K4). The dispersed pattern of H3(K9) dimethylation was stable even at the nuclear periphery of HDACi-treated cells. After TSA and NaBt treatment, the HP1 proteins were repositioned more internally in the nucleus, being closely associated with interchromatin compartments, while centromeric heterochromatin was relocated closer to the nuclear periphery. These findings strongly suggest dissociation of HP1 proteins from peripherally located centromeres in a hyperacetylated and H3(K4) dimethylated environment. We conclude that inhibition of histone deacetylases caused dynamic reorganization of chromatin in parallel with changes in its epigenetic modifications.

• MeSH
• apoptóza účinky léků   MeSH
• buněčné jádro účinky léků   enzymologie   genetika   metabolismus   MeSH
• buněčné linie MeSH
• buněčný cyklus účinky léků   MeSH
• buňky HT-29 MeSH
• chromatin metabolismus   MeSH
• chromozomální proteiny, nehistonové antagonisté a inhibitory   metabolismus   MeSH
• histondeacetylasy metabolismus   MeSH
• histony metabolismus   MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory enzymů farmakologie   MeSH
• inhibitory histondeacetylas * MeSH
• interfáze účinky léků   MeSH
• kyselina máselná farmakologie   MeSH
• kyseliny hydroxamové farmakologie   MeSH
• lidé MeSH
• malobuněčný karcinom enzymologie   metabolismus   patologie   MeSH
• nádorové buněčné linie MeSH
• nádory plic enzymologie   metabolismus   patologie   MeSH
• nádory tračníku enzymologie   metabolismus   patologie   MeSH
• plod MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• chromatin MeSH
• chromozomální proteiny, nehistonové MeSH
• histondeacetylasy MeSH
• histony MeSH
• homolog proteinu s chromoboxem 5 MeSH
• inhibitory enzymů MeSH
• inhibitory histondeacetylas * MeSH
• kyselina máselná MeSH
• kyseliny hydroxamové MeSH
• trichostatin A MeSH Prohlížeč

The effect of gentamycin on bone marrow cells in unirradiated and irradiated mice was investigated by 3H-dTh incorporation into DNA using microautoradiography. Gentamycin was injected in vivo at 20 mg base/kg body weight at 8-h intervals during three days. In mice exposed to 4.78 Gy the injections of gentamycin were started on the 7th day after irradiation. In granulopoietic and erythropoietic cells the inhibition of entry of cells into S phase and the retardation of DNA replication was about 20%. The roughly 30% inhibition of entry of cells into S phase observed when the bone marrow cell population has been evaluated as a whole is discussed in terms of increased sensitivity of the young blast-like cells.

• MeSH
• buňky kostní dřeně * MeSH
• gentamiciny farmakologie   MeSH
• interfáze účinky léků   MeSH
• kostní dřeň účinky záření   MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• replikace DNA účinky léků   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• gentamiciny MeSH