scholarly journals Modeling Apoptotic Chromatin Condensation in Normal Cell Nuclei

2002 ◽  
Vol 277 (24) ◽  
pp. 21683-21690 ◽  
Author(s):  
Piotr Widlak ◽  
Olena Palyvoda ◽  
Slawomir Kumala ◽  
William T. Garrard
Keyword(s):  
Normal Cell ◽  
Chromatin Condensation ◽  
Cell Nuclei

Nuclear envelope removal/maintenance determines the structural and functional remodelling of embryonic red blood cell nuclei in activated mouse oocytes

Zygote ◽  
1998 ◽  
Vol 6 (1) ◽  
pp. 65-73 ◽  
Author(s):  
Daniel Szöllösi ◽  
Renata Czołowska ◽  
Ewa Borsuk ◽  
Maria S. Szöllösi ◽  
Pascale Debey
Keyword(s):  
Nuclear Envelope ◽  
Transcriptional Activity ◽  
Chromatin Condensation ◽  
Oocyte Activation ◽  
Cell Nuclei ◽  
Nuclear Envelope Breakdown ◽  
Mouse Oocytes ◽  
Female Pronucleus ◽  
Mouse Fetuses

SummaryNuclei of embryonic red blood cells (e-RBC) from 12-day mouse fetuses are arrested in Go phase of the cell cycle and have low transcriptional activity. These nuclei were transferred with help of polyethylene glycol (PEG)-mediated fusion to parthenogenetically activated mouse oocytes and heterokaryons were analysed for nuclear structure and transcriptional activity. If fusion proceeded 25–45 min after oocyte activation, e-RBC nuclei were induced to nuclear envelope breakdown and partial chromatin condensation, followed by formation of nuclei structurally identical with pronuclei. These ‘pronuclei’, similar to egg (female) pronuclei, remained transcriptionally silent over several hours of in vitro culture. If fusion was performed 1 h or later (up to 7 h) after activation, the nuclear envelope of e-RBC nuclei remained intact and nuclear remodelling was less spectacular (slight chromatin decondensation, formation of nucleolus precursor bodies). These nuclei, however, reinforced polymerase-II-dependent transcription within a few hours of in vitro culture. Our present experiments, together with our previous work, demonstrate that nuclear envelope breakdown/maintenance are critical events for nuclear remodelling in activated mouse oocytes and that somatic dormant nuclei can be stimulated to renew transcription at a time when the female pronucleus remains transcriptionally silent.

scholarly journals Influence of extract from shoots of Taxus baccata var. elegantissima on ultrastructure and tubulin cytoskeleton of meristematic cells of Allium cepa L. roots

2014 ◽  
Vol 71 (3) ◽  
pp. 211-221 ◽  
Author(s):  
Agnieszka Majewska ◽  
Mirosława Furmanowa ◽  
Kazimierz Głowniak ◽  
Joanna Guzewska ◽  
Alicja Zobel ◽  
...  
Keyword(s):  
Allium Cepa ◽  
Chromatin Condensation ◽  
Preprophase Band ◽  
Taxus Baccata ◽  
Cell Nuclei ◽  
Root Tips ◽  
Meristematic Cells ◽  
Allium Cepa L ◽  
Interphase Cells ◽  
Average Size

We investigated the influence of extract from <em>Taxus baccata</em> var. Elegantissima (TbE) shoots in 1:8 dilution, containing paclitaxel in concentration of 81,6 µg/g fresh mass on ultrastructure and tubulin cytoskeleton of meristematic cells of <em>Allium cepa</em> L. root tips. Incubation time 3, 6, 12 and 24 h was followed with postincubation in water for 12 and 24 h. During shorter incubation (till 12 h) the surface of the cell nuclei decreased and chromatin became condensed (in comparison to control) but after 24 h the average surface increased and chromatin condensation decreased. In the course of incubation the average size of plastids and vacuoles increased. Moreover, after treatment mitochondria and plastids showed degradation of ultrastructure, which was reversed after 12 h of postincubation. Immunocytochemical assays demonstrated that in the course of incubation in the ThE extract, the tubulin cytoskeleton became partially disorganised. In most interphase cells, cortical microtubules (MTs) lost their oval transverse orientation. The preprophase band (PPB) position in the cell was often asymmetrical. The MTs array of the karyokinetic spindle and phragmoplast was also disturbed. These alterations were completely reversed during postincubation.

Particles in bulk milk capable of causing falsely high electronic cell counts

1982 ◽  
Vol 49 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Alan W. Hill ◽  
Kenneth G. Hibbitt ◽  
Jonathon Davies
Keyword(s):  
Cell Count ◽  
Normal Cell ◽  
The Other ◽  
Cell Nuclei ◽  
Casein Micelles ◽  
Cell Counts ◽  
Bulk Milk ◽  
Milking Machine

SUMMARYBulk milk with an apparently high electronic cell count (ECC) was found to have a normal cell count when the latter was determined directly with a microscope or when cell nuclei were counted with a Fossomatic apparatus. Particles in the form of collapsed spheres formed by aggregated casein micelles were found in bulk milk which accounted for the falsely high ECC values. The ECC value agreed with the values obtained by the other methods if the milk was heated to 55 °C for 15 min before fixation. The shape of the particles and the fact that they were only present after the milk had passed through the milking machine suggested that they may be produced as vacuum vacuoles arising from cavitation in the pump.

scholarly journals Inheritance of gene density–related higher order chromatin arrangements in normal and tumor cell nuclei

2003 ◽  
Vol 162 (5) ◽  
pp. 809-820 ◽  
Author(s):  
Marion Cremer ◽  
Katrin Küpper ◽  
Babett Wagler ◽  
Leah Wizelman ◽  
Johann v. Hase ◽  
...  
Keyword(s):  
Tumor Cell ◽  
Cell Lines ◽  
Radial Distribution ◽  
Normal Cell ◽  
Cell Types ◽  
Higher Order ◽  
Gene Density ◽  
Tumor Cell Lines ◽  
Cell Nuclei ◽  
Significant Difference

A gene density–related difference in the radial arrangement of chromosome territories (CTs) was previously described for human lymphocyte nuclei with gene-poor CT #18 located toward the nuclear periphery and gene-dense CT #19 in the nuclear interior (Croft, J.A., J.M. Bridger, S. Boyle, P. Perry, P. Teague, and W.A. Bickmore. 1999. J. Cell Biol. 145:1119–1131). Here, we analyzed the radial distribution of chromosome 18 and 19 chromatin in six normal cell types and in eight tumor cell lines, some of them with imbalances and rearrangements of the two chromosomes. Our findings demonstrate that a significant difference in the radial distribution of #18 and #19 chromatin is a common feature of higher order chromatin architecture in both normal and malignant cell types. However, in seven of eight tumor cell lines, the difference was less pronounced compared with normal cell nuclei due to a higher fraction of nuclei showing an inverted CT position, i.e., a CT #18 located more internally than a CT #19. This observation emphasizes a partial loss of radial chromatin order in tumor cell nuclei.

scholarly journals Cadmium (II)-Induced Oxidative Stress Results in Replication Stress and Epigenetic Modifications in Root Meristem Cell Nuclei of Vicia faba

Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 640
Author(s):  
Aneta Żabka ◽  
Konrad Winnicki ◽  
Justyna Teresa Polit ◽  
Mateusz Wróblewski ◽  
Janusz Maszewski
Keyword(s):  
Oxidative Stress ◽  
Cell Cycle ◽  
Dna Replication ◽  
Nuclear Dna ◽  
Chromatin Condensation ◽  
Replication Stress ◽  
Root Apical Meristem ◽  
H2o2 Production ◽  
Cell Nuclei ◽  
Meristem Cell

Among heavy metals, cadmium is considered one of the most toxic and dangerous environmental factors, contributing to stress by disturbing the delicate balance between production and scavenging of reactive oxygen species (ROS). To explore possible relationships and linkages between Cd(II)-induced oxidative stress and the consequent damage at the genomic level (followed by DNA replication stress), root apical meristem (RAM) cells in broad bean (V. faba) seedlings exposed to CdCl2 treatment and to post-cadmium recovery water incubations were tested with respect to H2O2 production, DNA double-strand breaks (γ-phosphorylation of H2AX histones), chromatin morphology, histone H3S10 phosphorylation on serine (a marker of chromatin condensation), mitotic activity, and EdU staining (to quantify cells typical of different stages of nuclear DNA replication). In order to evaluate Cd(II)-mediated epigenetic changes involved in transcription and in the assembly of nucleosomes during the S-phase of the cell cycle, the acetylation of histone H3 on lysine 5 (H3K56Ac) was investigated by immunofluorescence. Cellular responses to cadmium (II) toxicity seem to be composed of a series of interlinked biochemical reactions, which, via generation of ROS and DNA damage-induced replication stress, ultimately activate signal factors engaged in cell cycle control pathways, DNA repair systems, and epigenetic adaptations.

scholarly journals DNA and heterochromatin cycles in male gamete development of Oedogonium

2014 ◽  
Vol 50 (1-2) ◽  
pp. 349-352
Author(s):  
S. P. Shpilevaya
Keyword(s):  
Optical Density ◽  
Cell Nucleus ◽  
Mother Cell ◽  
Chromatin Condensation ◽  
Male Gamete ◽  
Cell Nuclei ◽  
Optimal Density ◽  
Gamete Formation ◽  
Two Peaks ◽  
Oedogonium Cardiacum

In antheridial nuclei of <em>Oedogonium cardiacum</em> (Hass.) Wittr. during male gamete formation, the DNA presynthetic period is shortened, the synthetic and postsynthetic periods are lengthened (G<sub>1</sub> - 15%, S - 58%, G<sub>2</sub> - 29%) as compared with those in vegetative cells (G<sub>1</sub> - 31%, S - 44%, G<sub>2</sub> - 25%). Differences in the ratio of the relative amounts of eu- and heterochromatin in the antheridial mother cell (AMC) nucleus and antheridial cell nucleus were determined. Hydrolysis curves revealed two peaks of higher optical density (3.5 and 8.5 h hydrolysis with 5N HCl at 23°C), corresponding to eu- and heterochromatin. Heterochromatin in antheridial cell nuclei was characterized by a greater optical density than that of heterochromatin in AMC nuclei. The presence of two local optimal density maxima is considered as facultative and constitutive increasing of chromatin condensation in the process of male cell development.

scholarly journals A fractionated cell-free system for analysis of prophase nuclear disassembly.

1986 ◽  
Vol 103 (6) ◽  
pp. 2073-2081 ◽  
Author(s):  
F A Suprynowicz ◽  
L Gerace
Keyword(s):  
Chromatin Condensation ◽  
Chinese Hamster ◽  
Nuclear Lamina ◽  
Biochemical Properties ◽  
Nuclear Pore ◽  
Nuclear Pore Complexes ◽  
Cell Nuclei ◽  
Free System ◽  
Cell Free System

We describe a cell-free system in which a postribosomal supernatant (s140) from metaphase Chinese hamster ovary (CHO) cells induces prophase-like changes in isolated CHO cell nuclei, including chromatin condensation, and nuclear envelope and lamina disassembly. These events are strongly promoted by gamma-S-ATP and an ATP-regenerating system, and do not take place with an s140 derived from G2-phase cells. The metaphase cell s140 also induces disassembly of an isolated nuclear lamina fraction that is depleted of membranes, chromatin, and nuclear pore complexes. Disassembly of the isolated lamina is accompanied by phosphorylation of the major lamina proteins (lamins A, B, and C) to levels characteristic of metaphase cells. Kinetic analysis of lamina depolymerization indicates that cooperativity may be involved in this process. The biochemical properties of in vitro lamina disassembly suggest that the activity that depolymerizes the lamina during mitosis is soluble in metaphase cells, and support the notion that this activity is a lamin protein kinase.

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