151 research outputs found
On Possibility of Asteroids Taxonomy Classification Based on Multicolor Photometry in the LYRA-B Space Experiment
Possibility of carrying out of asteroids taxonomy classification has been analyzed based on the LYRA-B space experiment data about multicolor photometry in 10 spectral bands in the range from 175 to 1050 nm. Estimations of integral fluxes have obtained for the bands which overlapped with the range of the Bus-DeMeo taxonomy that is from 450 to 2450 nm. Drew a conclusion that the multicolor photometry data allow to carry out of asteroids taxonomy classification for main spectral classes.Анализируется возможность проведения таксономической классификации астероидов на основе данных космического эксперимента «Лира-Б» о многоцветной фотометрии в 10 полосах в диапазоне от 175 до 1 050 нм. Получены оценки интегральных потоков в полосах, перекрывающихся с диапазоном, применяемым в таксономии Бас-ДеМео от 450 до 2 450 нм. Сделан вывод, что данные многоцветной фотометрии позволят выполнить таксономическую классификацию астероидов для основных спектральных классов.Работа выполнена при поддержке постановления №211 Правительства Российской Федерации (контракт №02.A03.21.0006) и Министерства образования и науки Российской Федерации (базовая часть государственного задания, РК № AAAA–A17–117030310283–7)
Correctability of thyroid dysfunction by interm ittent hypobaric hypoxia
The work is devoted to studying the effect of intermittent hypobaric hypoxia on thyroid dysfunction. Simulation of thyroid dysfunction by oral introduction of levothyroxine sodium in a dose of 50 mg/kg body weight of the animal is accompanied by an increase in the concentration thyroid hormones and decreased levels of TSH in the blood, decrease blood supply to the thyroid gland and the structural changes, characteristic of reducing its functional activity. The use of intermittent hypobaric hypoxia reduces recovery time of hormonal imbalance in the pituitary gland-thyroid gland, structural, functional and microvascular disturbances in the thyroid gland.Работа посвящена изучению влияния прерывистой гипобарической гипоксии натиреоидную дисфункцию. Моделирование тиреоидной дисфункции путем перорального введения левотироксина натрия в дозе 50 мкг/кг массы тела животного сопровождается увеличением концентрации тиреоидных гормонов и снижением уровня ТТГ в крови, уменьшением кровоснабжения щитовидной железы и структурными изменениями, характерными для понижения её функциональной активности. Применение прерывистой гипобарической гипоксии сокращает сроки восстановления гормонального дисбаланса в системе гипофиз-щитовидная железа, структурно-функциональных и микрососудистых наррений в щитовидной железе
The possibility to decrease biological activity of chrysotile-asbestos
The paper presents a study of natural chrysotile and 15 samples modified using different temperature and pressure. The morphology, dimensions, chemical composition, crystalline structure, and technologic characteristics of the samples studied were similar. The numbers of negatively charged centers on the surface of fibers were about the same in all the samples. In two modified asbestos samples the number of positively charged centers was less than in the native one. In these samples the energy of interaction of charged centers with macromolecules of rodamin and eozin was also less than in the sample of natural chrysotile. It directly correlated with cytotoxicity and mutagenicity of them. The principal possibility to decrease the biological activity of asbestos has been discussed
A NEW METHOD TO ASSESS FUNCTIONAL ACTIVITY OF SERUM COMPLEMENT SYSTEM
Complement system is an important component of innate immunity, providing primary protection against pathogens invading the body. In addition, it was shown that the complement system is associated with many diseases, not only autoimmune and infectious, but also mental disorders. In this regard, it is necessary to develop affordable and fast method of measuring activity of the complement system in real-time mode. We present a new semi-automated method for assessment of serum complement activity. The assay is based on cytolytic action of complement system upon the ciliate organism Tetrahymena pyriformis. This method consists in repeated counting of live Tetrahymena motile cells by means of specially developed Biolat device, which consists of two video cameras, light sources, and movable round plate. The plate has two rows of holes. The device also includes microprocessor control unit based on AutoCiliata software, intended for control of operation module and counting the surviving cell. The calculations are based on fixation of two sequential video-frames, with subsequent software image processing. Cell death events were observed upon incubation in triethanolamine (TEA) buffer containing 5% of blood serum. We have also compared complement activity in different buffers, i.e., standard medium for culturing of ciliates, Veronal-Medinalum buffer, and the TEA buffer. TEA buffer was found superior to the Veronal buffer when applied in the test system. The time of cell death in the TEA-buffered medium containing 5% serum was < 15 minutes for all the sera studied. The parameters denoting serum complement activity were as follows: a half-life time for the moving cells (TLD50), and a similar value for 100% cell inactivation (1/TLD50, functional activity of the complement system, ACS). The sensitivity of this assay was calculated from dependencies between TLD50 and ACS, and actual serum concentrations. We have suggested an opportunity for evaluation of an integral complement activity, and interrelations between the intensity of synthesis and consumption of its major effector proteins. In the course of this study, we have tested different concentrations of Ca++ and Mg++ ions in the incubation buffer, with optimal physiological concentrations of2.5 mMand1.5 mM, respectively. We have also estimated statistical precision characteristics for pre-analytical and analytical steps of the method. The average coefficients of variation (CV) were 3.9% and 2.7%, respectively, thus satisfying the reliability criteria in research. A short performance time of the study suggests its potential application in clinical practice, including online examination regimens. A method for semi-automatic measurement of serum complement activity could be applicable in daily clinical practice, including the online performance
Permitted Oxygen Abundances and the Temperature Scale of Metal-Poor Turn-Off Stars
We use high quality VLT/UVES published data of the permitted OI triplet and
FeII lines to determine oxygen and iron abundances in unevolved (dwarfs,
turn-off, subgiants) metal-poor halo stars. The calculations have been
performed both in LTE and NLTE, employing effective temperatures obtained with
the new infrared flux method (IRFM) temperature scale by Ramirez & Melendez,
and surface gravities from Hipparcos parallaxes and theoretical isochrones. A
new list of accurate transition probabilities for FeII lines, tied to the
absolute scale defined by laboratory measurements, has been used. We find a
plateau in the oxygen-to-iron ratio over more than two orders of magnitude in
iron abundance (-3.2 < [Fe/H] < -0.7), with a mean [O/Fe] = 0.5 dex (sigma =
0.1 dex), independent of metallicity, temperature and surface gravity.
According to the new IRFM Teff scale, the temperatures of turn-off halo stars
strongly depend on metallicity, a result that is in excellent qualitative and
quantitative agreement with stellar evolution calculations, which predict that
the Teff of the turn-off at [Fe/H] = -3 is about 600-700 K higher than that at
[Fe/H] = -1.Comment: In press, Ap
HEMITSELLYULOZA AND THEIR NANOBIOCOMPOSITES - PERSPECTIVE NANOSTRUCTURED SINBIOTICS
Natural nanocomposites hemicellulose arabinogalactan and flavonoids isolated (from Siberian larch) and characterized. Additionally nitro- and sulfo-esters of arabinogalactan and its calcium salt are synthesized and. characterized. All of the derivatives of the beta-hemicellulose arabinogalactan. are water-soluble and are promising prebiotics on the example test-strain Bifidobacterium bifidum. (except for the nitrate esters of arabinogalactan)
Transcriptome-Wide Binding Sites for Components of the Saccharomyces cerevisiae Non-Poly(A) Termination Pathway: Nrd1, Nab3, and Sen1
RNA polymerase II synthesizes a diverse set of transcripts including both protein-coding and non-coding RNAs. One major difference between these two classes of transcripts is the mechanism of termination. Messenger RNA transcripts terminate downstream of the coding region in a process that is coupled to cleavage and polyadenylation reactions. Non-coding transcripts like Saccharomyces cerevisiae snoRNAs terminate in a process that requires the RNA–binding proteins Nrd1, Nab3, and Sen1. We report here the transcriptome-wide distribution of these termination factors. These data sets derived from in vivo protein–RNA cross-linking provide high-resolution definition of non-poly(A) terminators, identify novel genes regulated by attenuation of nascent transcripts close to the promoter, and demonstrate the widespread occurrence of Nrd1-bound 3′ antisense transcripts on genes that are poorly expressed. In addition, we show that Sen1 does not cross-link efficiently to many expected non-coding RNAs but does cross-link to the 3′ end of most pre–mRNA transcripts, suggesting an extensive role in mRNA 3′ end formation and/or termination
Genome-wide search for breast cancer linkage in large Icelandic non-BRCA1/2 families
Abstract
Introduction:
A significant proportion of high-risk breast cancer families are not explained by mutations in known genes. Recent genome-wide searches (GWS) have not revealed any single major locus reminiscent of BRCA1 and BRCA2, indicating that still unidentified genes may explain relatively few families each or interact in a way obscure to linkage analyses. This has drawn attention to possible benefits of studying populations where genetic heterogeneity might be reduced. We thus performed a GWS for linkage on nine Icelandic multiple-case non-BRCA1/2 families of desirable size for mapping highly penetrant loci. To follow up suggestive loci, an additional 13 families from other Nordic countries were genotyped for selected markers.
Methods:
GWS was performed using 811 microsatellite markers providing about five centiMorgan (cM) resolution. Multipoint logarithm of odds (LOD) scores were calculated using parametric and nonparametric methods. For selected markers and cases, tumour tissue was compared to normal tissue to look for allelic loss indicative of a tumour suppressor gene.
Results:
The three highest signals were located at chromosomes 6q, 2p and 14q. One family contributed suggestive LOD scores (LOD 2.63 to 3.03, dominant model) at all these regions, without consistent evidence of a tumour suppressor gene. Haplotypes in nine affected family members mapped the loci to 2p23.2 to p21, 6q14.2 to q23.2 and 14q21.3 to q24.3. No evidence of a highly penetrant locus was found among the remaining families. The heterogeneity LOD (HLOD) at the 6q, 2p and 14q loci in all families was 3.27, 1.66 and 1.24, respectively. The subset of 13 Nordic families showed supportive HLODs at chromosome 6q (ranging from 0.34 to 1.37 by country subset). The 2p and 14q loci overlap with regions indicated by large families in previous GWS studies of breast cancer.
Conclusions:
Chromosomes 2p, 6q and 14q are candidate sites for genes contributing together to high breast cancer risk. A polygenic model is supported, suggesting the joint effect of genes in contributing to breast cancer risk to be rather common in non-BRCA1/2 families. For genetic counselling it would seem important to resolve the mode of genetic interaction
Microprocessor mediates transcriptional termination of long noncoding RNA transcripts hosting microRNAs
MicroRNA (miRNA) play a major role in the post-transcriptional regulation of gene expression. Mammalian miRNA biogenesis begins with co-transcriptional cleavage of RNA polymerase II (Pol II) transcripts by the Microprocessor complex. While most miRNA are located within introns of protein coding genes, a substantial minority of miRNA originate from long non coding (lnc) RNA where transcript processing is largely uncharacterized. Here, by detailed characterization of liver-specific lnc-pri-miR-122 and genome-wide analysis, we show that most lnc-pri-miRNA do not use the canonical cleavage and polyadenylation (CPA) pathway but instead use Microprocessor cleavage to terminate transcription. Microprocessor inactivation leads to extensive transcriptional readthrough of lnc-pri-miRNA and transcriptional interference with downstream genes. Consequently we define a novel RNase III-mediated, polyadenylation-independent mechanism of Pol II transcription termination in mammalian cells
Successful Expansion but Not Complete Restriction of Tropism of Adeno-Associated Virus by In Vivo Biopanning of Random Virus Display Peptide Libraries
Targeting viral vectors to certain tissues in vivo has been a major challenge in gene therapy. Cell type-directed vector capsids can be selected from random peptide libraries displayed on viral capsids in vitro but so far this system could not easily be translated to in vivo applications. Using a novel, PCR-based amplification protocol for peptide libraries displayed on adeno-associated virus (AAV), we selected vectors for optimized transduction of primary tumor cells in vitro. However, these vectors were not suitable for transduction of the same target cells under in vivo conditions. We therefore performed selections of AAV peptide libraries in vivo in living animals after intravenous administration using tumor and lung tissue as prototype targets. Analysis of peptide sequences of AAV clones after several rounds of selection yielded distinct sequence motifs for both tissues. The selected clones indeed conferred gene expression in the target tissue while gene expression was undetectable in animals injected with control vectors. However, all of the vectors selected for tumor transduction also transduced heart tissue and the vectors selected for lung transduction also transduced a number of other tissues, particularly and invariably the heart. This suggests that modification of the heparin binding motif by target-binding peptide insertion is necessary but not sufficient to achieve tissue-specific transgene expression. While the approach presented here does not yield vectors whose expression is confined to one target tissue, it is a useful tool for in vivo tissue transduction when expression in tissues other than the primary target is uncritical
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