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Olga N. Danilevskaya Dmitri A. Petrov Maria N. Pavlova Akihiko Koga Elena V. Kurenova Daniel L. Hartl 《Chromosoma》1992,102(1):32-40
He-T sequences are a complex repetitive family of DNA sequences in Drosophila that are associated with telomeric regions, pericentromeric heterochromatin, and the Y chromosome. A component of the He-T family containing open reading frames (ORFs) is described. These ORF-containing elements within the He-T family are designated T-elements, since hybridization in situ with the polytene salivary gland chromosomes results in detectable signal exclusively at the chromosome tips. One T-element that has been sequenced includes ORFs of 1,428 and 1,614 bp. The ORFs are overlapping but one nucleotide out of frame with respect to each other. The longer ORF contains cysteine-histidine motifs strongly resembling nucleic acid binding domains of gag-like proteins, and the overall organization of the T-element ORFs is reminiscent of LINE elements. The T-elements are transcribed and appear to be conserved in Drosophila species related to D. melanogaster. The results suggest that T-elements may play a role in the structure and/or function of telomeres.by W. Hennig 相似文献
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Anna-Karin Gustavsson Rajarshi P. Ghosh Petar N. Petrov Jan T. Liphardt W. E. Moerner 《Molecular biology of the cell》2022,33(6)
Chromatin organization and dynamics are critical for gene regulation. In this work we present a methodology for fast and parallel three-dimensional (3D) tracking of multiple chromosomal loci of choice over many thousands of frames on various timescales. We achieved this by developing and combining fluorogenic and replenishable nanobody arrays, engineered point spread functions, and light sheet illumination. The result is gentle live-cell 3D tracking with excellent spatiotemporal resolution throughout the mammalian cell nucleus. Correction for both sample drift and nuclear translation facilitated accurate long-term tracking of the chromatin dynamics. We demonstrate tracking both of fast dynamics (50 Hz) and over timescales extending to several hours, and we find both large heterogeneity between cells and apparent anisotropy in the dynamics in the axial direction. We further quantify the effect of inhibiting actin polymerization on the dynamics and find an overall increase in both the apparent diffusion coefficient D* and anomalous diffusion exponent α and a transition to more-isotropic dynamics in 3D after such treatment. We think that in the future our methodology will allow researchers to obtain a better fundamental understanding of chromatin dynamics and how it is altered during disease progression and after perturbations of cellular function. 相似文献
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Elke EM Brouwers Alwin DR Huitema Jos H Beijnen Jan HM Schellens 《BMC clinical pharmacology》2008,8(1):7
Background
The aim of this study was to evaluate long-term platinum retention in patients treated with cisplatin and oxaliplatin. 相似文献27.
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Spreading of mesenchymal cells of human embryo on plastic and on type I collagens (from rat, sheep, and ox) was studied. Spreading of the cells on collagens was stronger than that in control, but no differences between different collagens were revealed. The cell perimeter, the spreading coefficient, and the cell projection area on the substrate were used as morphometric parameters. The spreading of cells was monitored for 0.5–2 h after plating. During the spreading both on plastic and on collagen, groups of small cells were revealed as separate subpopulations. As a whole, such cells accounted for 9% of the cell population in control and for 2% in experiment. We assume that this cell type is associated with a special independent functional state of the cells that precedes cell spreading. 相似文献
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E. A. Azizov A. V. Babarykin A. V. Voronin V. K. Gusev A. Yu. Malyshev V. K. Markov A. A. Petrov V. G. Petrov Yu. V. Petrov V. V. Rozhdestvenskii N. V. Sakharov 《Plasma Physics Reports》2004,30(5):422-431
A weeping pulsed radar reflectometer designed for measuring the spatial electron density distribution in the Globus-M spherical tokamak with a minor plasma radius of a=24 cm, a major radius of R=36 cm, a toroidal field of B T=0.5 T, a plasma current of I p=200 kA, and an average density of n=(3–10)×1013 cm?3 is described. The reflectometer operation is based on the reflection of microwaves with a carrier frequency f from a plasma layer with the critical density n=(0.0111f)2, where n is the electron density in units of 1014 cm?3 and f is the microwave frequency in GHz. By simultaneously probing the plasma at different frequencies, it is possible to recover the electron density profile. Microwave pulses with different frequencies are obtained by frequency sweeping. To increase the range of measured densities, channels with fixed frequencies are also used; as a result, the instrument has eleven frequency channels: a 19.5-GHz channel, eight channels in the 26-to 40-GHz frequency range, a 51.5-GHz channel, and a 60-GHz channel, which corresponds to eleven points in the density profile: 0.47×1013 cm?3, eight points in the (0.8–1.95)×1013-cm?3 range, 3.27×1013 cm?3, and 4.5×1013 cm?3. The reflectometer allows detailed measurements of the density profile with a time resolution of several tens of microseconds, which can be useful, in particular, in studying the processes related to the formation of an internal transport barrier in plasma. The first results obtained using this reflectometer in the Globus-M tokamak under various operating conditions are discussed. 相似文献