30 research outputs found

    Paucity and preferential suppression of transgenes in late replication domains of the D. melanogaster genome

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    <p>Abstract</p> <p>Background</p> <p>Eukaryotic genomes are organized in extended domains with distinct features intimately linking genome structure, replication pattern and chromatin state. Recently we identified a set of long late replicating euchromatic regions that are underreplicated in salivary gland polytene chromosomes of <it>D. melanogaster</it>.</p> <p>Results</p> <p>Here we demonstrate that these underreplicated regions (URs) have a low density of <it>P</it>-<it>element </it>and <it>piggyBac </it>insertions compared to the genome average or neighboring regions. In contrast, <it>Minos</it>-based transposons show no paucity in URs but have a strong bias to testis-specific genes. We estimated the suppression level in 2,852 stocks carrying a single <it>P</it>-<it>element </it>by analysis of eye color determined by the mini-<it>white </it>marker gene and demonstrate that the proportion of suppressed transgenes in URs is more than three times higher than in the flanking regions or the genomic average. The suppressed transgenes reside in intergenic, genic or promoter regions of the annotated genes. We speculate that the low insertion frequency of <it>P-elemen</it>ts and <it>piggyBac</it>s in URs partially results from suppression of transgenes that potentially could prevent identification of transgenes due to complete suppression of the marker gene. In a similar manner, the proportion of suppressed transgenes is higher in loci replicating late or very late in Kc cells and these loci have a lower density of <it>P-elements </it>and <it>piggyBac </it>insertions. In transgenes with two marker genes suppression of mini-<it>white </it>gene in eye coincides with suppression of <it>yellow </it>gene in bristles.</p> <p>Conclusions</p> <p>Our results suggest that the late replication domains have a high inactivation potential apparently linked to the silenced or closed chromatin state in these regions, and that such inactivation potential is largely maintained in different tissues.</p

    Fizikalni mehanizmi i metode u tumorskim terapijama i prijenosu lijekova do tumora

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    In addition to several well-known drug delivery strategies developed to facilitate effective chemotherapy with anticancer agents, some new approaches have been recently established, based on specific effects arising from the applications of ultrasound, magnetic and electric fields on drug delivery systems. This paper gives an overview of newly developed methods of drug delivery to tumors and of the related anticancer therapies based on the combined use of different physical methods and specific drug carriers. The conventional strategies and new approaches have been put into perspective to revisit the existing and to propose new directions to overcome the threatening problem of cancer diseases.Osim dobro poznatih metoda prijenosa lijekova u kemoterapijskom pristupu liječenja tumora, nedavno su otkriveni novi načini prijenosa koji se zasnivaju na specifičnim mehanizmima uzrokovanim upotrebom ultrazvuka, magnetskih i električnih polja. Članak sadrži prikaz fizikalnih mehanizama na kojima se temelje ove nove metode, kao i pregled novootkrivenih prijenosnika lijekova (Pluronske micele, magnetoliposomi, magnetski fluidi), novih terapija tumora (magnetska hipertermija, elektrokemoterapija) i najnovijih istraživanja temeljenih na fizikalnom pristupu ovoj problematici

    Alien and keystone mammal species in ecosystems: report on the XХІII Theriological School-Workshop

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    The XXIII Theriological school-workshop «Alien and keystone mammal species in ecosystems» was held in 26 September to 1 October 2016. It was organized by the Ukrainian Theriological Society, Slobozhanskyi National Park and Research Institute of Biology at V.N. Karazin Kharkiv National University. In the workshop participated 20 zoologists from 13 institutions at different regions of Ukraine. The workshop was held concerning a few topics: plenary reports, reports and discussions about alien and keystone mammal species, information section, round table discussions and master classes, sightseeing day and «New names in theriology» session. The Odesa was recommended as the venue of the next Theriological School

    Synthesis And Investigation Of Magnetic Properties Of Substituted Ferrite Nanoparticles Of Spinel System Mn1-XZnX[Fe2-YLY]O4

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    Superparamagnetic nanoparticles of the spinel ferrite four-element system Mn1-xZnx[Fe2-yLy]O4 (where L:Gd3+, La3+, Ce3+, Eu3+, Dy3+, Er3+,Yb3+) were synthesized by the co-precipitation method. The magnetic moments of the 10 nm diameter nanoparticles were comparable to the ones of Fe3O4 nanoparticles. A comparatively low TC (∼52-72 °C) was observed for some of the compositions. The heating mechanism of the superparamagnetic particles in the AC magnetic field at radiofrequency range is discussed and especially the absence of the hysteresis loop in the M-H curve at room temperature. One possible explanation-spontaneous particle agglomeration-was experimentally verified. © 2006 Elsevier B.V. All rights reserved

    Terahertz Spectroscopy Of Tnt For Explosive Detection

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    Transmittance spectra of solid and vapor samples of trinitrotoluene (TNT) in the spectral range 0.6 to 10 THz at resolutions up to 1 GHz are reported. Uniform solid samples of ∼100 μrn thickness gave stronger absorption and more resolved structure than previous studies. New absorption lines for TNT solid below 100 cm-1 are reported. A heated 10 m multpass White cell was used for spectroscopy of the vapor. Strong absorption bands yield unexpectedly large absorption cross sections for the anticipated saturated vapor pressure at the cell temperature, leaving their assignment to TNT in doubt. These results indicate that path lengths exceeding 10 m and temperatures higher than 40 C, or significantly higher instrumental sensitivity, are needed for sensing of TNT vapor in the spectral range 0.6 to 10 THz

    Far Infrared Spectroscopy Of Carbonate Minerals

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    This study presents far infrared spectra in the range 650-70 cm -1 of 18 common and rare carbonate minerals. Mineral samples of known provenance are selected and physically characterized to determine the purity of the crystalline phase and their composition. The fine ground mineral powders are embedded in polyethylene pellets, and their transmittance spectra are collected with a Fourier spectrometer. The far infrared spectra of different carbonate minerals from the same structural group have well-defined similarities. Observed shifts generally manifest the mass effect of the constituent metal cations. Remarkable spectral differences occur for different carbonates in the far IR region and may serve as fingerprints for mineral identification and are more useful identifiers of carbonate species than those in any other infrared range. For some of the minerals studied here, like kutnohorite, artinite, gaylussite, and trona, no far infrared spectra to that extend (up to 70 cm-1) have been found in literature

    Evaluation of ferromagnetic #uids and suspensions for the site-speci&quot;c radiofrequency-induced hyperthermia of MX11 sarcoma cells in vitro

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    Abstract Seventeen di!erent ferromagnetic #uids and suspensions were prepared and evaluated for application in radiofrequency-induced hyperthermia. Speci&quot;c power absorption rates were measured at 0.88 MHz to range from 0 to 240 W per gram of iron for di!erent preparations. Survival of MX11 cells mixed with ferro#uids and subjected to radiofrequency was much lower than with RF without ferro#uid or ferro#uid alone
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