387 research outputs found

    The competency levels of disabled students who study in university

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    The article is devoted to the problem of inclusive education of students with disabilities at the university. The article analyses the study of the readiness of students with disabilities to research activitie

    The Impact of the Functional Layer Composition of Glucose Test-Strips on the Stability of Electrochemical Response

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    Herein, the impact of the chemical stability of RedOx mediator ferricyanide, K3 [Fe(CN)6 ] (FC), a type of buffer solution used for bioreceptor preparation, gel composition (carboxymethylcellulose, CMC, Aerosile, AS, and alginate, ALG) on the long term stability of glucose test-strips and their analytical performance was examined. By simple addition of ALG to the functional gel aiming to improve its viscosity, we managed to enhance the sensitivity of conventional CMC-containing amperometric glucose test-strips from 3.3 µA/mM to 3.9 µA/mM and extend their shelf life from 8 months to 1.7 years. Moreover, during the course of investigations, it was revealed that the activity of enzyme in dependence with the used buffer did not linearly correlate with its activity in a dried functional layer, and the entire long-term electrochemical signal of glucose test-strips was determined by RedOx mediator FC chemical stability. The most stable and sensitive test-strips were obtained by the screen-printing approach from a gel containing 24 mg/mL GOx prepared in citrate buffer with pH 6, 200 mg/mL of FC and 10 mg/mL of CMC supplemented with 25 mg/mL of ALG

    THE BIOSYNTHESIS REGULATION OF POTATO STEROIDAL GLYCOALKALOIDS

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    Potato steroidal glycoalkaloids (SGAs) compose a part of plant immunity. Some of their modified variants are toxic to humans. In the course of potato domestication, plants with a lower SGA level were selected. The advent of approaches for manipulation with the regulation of metabolic pathways provides an opportunity to overcome the undesirable direct relationship between the potato resistance to pests and the toxicity of its tubers. However, for such a fine regulation, a deep knowledge of the regulatory network of potato SGA biosynthesis is required. The purpose of this review is to summarize the information on the known SGA biosynthesis genes in plants and the results of the investigation of these genes in potato, as well as to consider the mechanisms of the SGA protective toxic action against pathogens and pests. The SGA biosynthesis is realized via the cytosolic mevalonate pathway and consists of three stages. The first two stages are required for the synthesis of primary metabolites, and lead to cycloartanol and cholesterol, respectively. Twelve enzymes are involved in the biosynthesis, and the half of them are involved in the biosynthesis of phytosterols, which is a branch of the first stage of this metabolic pathway. In the potato leaves with an excess of phytosterols, the synthesis switches to SGAs, increasing the content of the latter. In tubers, with an excess of SGA precursors, they are involved in the synthesis of lanosterol, supporting in this way the stable level of SGA. The importance of structural genes encoding the enzymes of the first two stages of biosynthesis does not allow us to consider them as a target for knockout in order to reduce the level of SGAs. However, information about the tissue-specific mechanisms of switching between the pathways of synthesis of SGA and other compounds having common precursors with SGAs can be used to manipulate the tissue-specific level of steroidal glycoalkaloids. At the third stage (the synthesis of glycoalkaloids from cholesterol), about 20 enzymes participate. In the potato genome, 14 corresponding genes were identified, 8 of which were studied in detail using reverse genetics approaches. As a promising target for reducing SGA levels in tubers, the genes encoding PGA enzymes (belonging to the CYP72 subfamily cytochrome-P450-dependent monooxygenases catalyzing the conversion of hydrocholesterol to trihydrocholesterol) and SGT (SGA glycosyltransferases that catalyze the conversion of solanidine to its toxic glycosylated derivatives α-solanine and α-chaconine) are considered. Cis-regulatory elements in the promoter regions of some glycoalkaloid biosynthesis genes, including elements responsible for tissue-specific expression, are described. The accumulated information provides the base for creating potato genotypes with tissue-specific regulation of SGAs, in which high levels of SGAs in leaves will remain to protect against pathogens and pests and, at the same time, the synthesis of toxic substances in tubers will be suppresse

    Current achievements in modifying crop genes using CRISPR/Cas system

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    With the advent of the new genome editing tool of target-specifically customizable endonucleases, a huge variety of novel opportunities have become feasible. The crop improvement is one of the main applications of genome editing in plant science and plant biotechnology. The amount of publications referring to genome editing and CRISPR/Cas system based molecular tools application in crops is permanently growing. The aim of this study is the systematization and cataloging of these data. Earlier we published the first catalog of targeted crop genome modifications as of February 10, 2017. The current review is an update of the catalog; it covers research papers on crop genome modifications from February 10, 2017 to August 17, 2018, found by searching 47 crop names in the Scopus database. Over one year and a half, 377 articles mentioning CRISPR/Cas and crop names have been published, of which 131 articles describe an experimental application of this tool for editing 193 genes in 19 crops, including rice with the largest number of genes modified (109 genes). Editing 50 of 193 genes was aimed at crop improvement. The catalog presented here includes these 50 genes, specifying the cultivars, each gene and gene product function, modification type and delivery method used. The current full list of genes modified with CRISPR/Cas with the aim of crop improvement is 81 in 16 crops (for 5 years from August 2013 to August 2018). In this paper, we also summarize data on different modifications types in different crops and provide a brief review of some novel methods and approaches that have appeared in crop genome editing research over the reviewed period. Taken together, these data provide a clear view on current progress in crop genome modifications and traits improvement using CRISPR/Cas based genome editing technology

    New records of lichens and allied fungi from the Leningrad Region, Russia. VIII

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    Thirteen species and one variety of lichens, nine lichenicolous and two saprobic fungi are reported for the first time for St. Petersburg, the whole Leningrad Region or its western or eastern parts. The lichens Bacidina brandii, B. neosquamulosa, Porina leptalea, Rinodina aspersa and the lichenicolous fungus Scutula dedicata are reported for the first time for Russia, lichenicolous fungus Lichenoconium aeruginosum – for European Russia, the lichen Tetramelas chloroleucus, lichenicolous fungi Lichenoconium pyxidatae and Tremella cetrariicola are new for the North-Western European Russia. The most interesting records are briefly discussed.

    Arctic and tundra soils on the new digital soil map of Russia, 1 : 2.5 M scale

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    V.V. Dokuchaev Soil Science Institute has initiated a project on compilation of a new Digital Soil Map of Russia on the basis of the Soil Map of the Russian Federation (SMRF) 1 : 2.5 M scale (1988) revised and interpreted in ideology and nomenclature of the new substantive-genetic Classification System of Russian Soils (CSRS). The first stage implies the conversion of soil mapping units on the original map into the CSRS with a corresponding renaming of soils in the attribute database to the digitized version of the map for each soil polygon. During the second stage, a new digital model of the soil cover is developed with the use of digital soil mapping technologies, basic soil map, and new materials, including satellite images and digital elevation models. The legend section “Tundra Soils” contains 16 soil units forming their own areas or found in various combinations (soil complexes). As a result of the reclassification and careful analysis of each soil polygon, the soils of Arctic and Subarctic tundra have obtained a more detailed and differential representation on the new map, and their diagnostics based on the morphology of the profiles and major soil properties have been specified. The most significant changes in the initial content of the map concern the soils referred to as gley soils on the SMRF. A separate group of cryozemic soils has been specified. Weakly developed soils (petrozems, psammozems, and pelozems) and lithozems have been introduced on the map for the first time. Differential decisions are suggested for the soils of “spotty tundra” with sorted and nonsorted circles and for the soils of cryogenic fissures and cracks. The results of the study have made it possible to refine the diagnostics and nomenclature of soils in the CSRS

    Hanbury Brown and Twiss interferometry at a free-electron laser

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    We present measurements of second- and higher-order intensity correlation functions (so-called Hanbury Brown and Twiss experiment) performed at the free-electron laser (FEL) FLASH in the non-linear regime of its operation. We demonstrate the high transverse coherence properties of the FEL beam with a degree of transverse coherence of about 80% and degeneracy parameter of the order 10^9 that makes it similar to laser sources. Intensity correlation measurements in spatial and frequency domain gave an estimate of the FEL average pulse duration of 50 fs. Our measurements of the higher-order correlation functions indicate that FEL radiation obeys Gaussian statistics, which is characteristic to chaotic sources.Comment: 19 pages, 6 figures, 1 table, 40 reference

    Current trends in soil micromorphology: bibliometric approach

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    The analysis of publications has shown that the period of intensive development of several spheres in micromorphology in the second half of the XX century was followed by a period when micromorphology became more required in applied research. Addressing micromorphology for solving pedogenetic and taxonomic questions became reduced both in Russia and in the world. Further progress of traditional micromorphology in Russia is expected owing to application of sophisticated equipment, participation in hierarchical morphogenetic studies, as well as to the possibility for students and professionals to work with a “database” - collection of thin sections representing a broad array of soils. This work is initiated at V.V. Dokuchaev Soil Science Institute, where many thin sections are already accumulated, and most specialists worked and are now working there

    Crop genes modified using CRISPR/Cas system

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    The CRISPR/Cas system is the most promising among genome editing tools. It can provide the development of modified nontransgenic plants with the possibility of simultaneous multiple targeted mutations. The purpose of this review is to analyze published papers describing the utilization of the CRISPR/Cas system for crop gene modification in order to assess the potential of this technology as a new plant breeding technique. The search for “CRISPR & crop name” within article titles, abstracts and keywords in the Scopus database was carried out for 45 crops. Among a total of 206 search results, only 88 have been recognized as original articles describing editing crop genes with the CRISPR/Cas system. A total of 145 target genes of 15 crops are described in these 88 articles, including rice with the largest number of genes modified (78 genes). In these studies, the ability to get transgene-free modified plants was widely demonstrated. However, in most cases research was aimed at the approbation of the technology or was to elucidate target gene function, while modification of just 37 target genes was related with crop improvement. We present here a catalogue of these genes. In most of these cases, modifications resulted in knockout of the genes such as negative growth and development regulators or negative regulators of plant resistance. In most cases, the phenotype of modified plants was assessed, and the presence of desired changes was shown. However, since the estimated number of “negative regulators” is limited in plant genomes, the CRISPR-directed gene knockout has a restricted potential for crop improvement. Intensive application of the CRISPR/Cas system for more complicate modifications such as replacement of defect alleles by functional ones or insertion of a desired gene is required (so far reports about such modifications are very rare in crops). In addition, to provide a basis for broad practical application of CRISPR/Cas-based genome editing, more cultivars of crop species should be involved in ongoing studies. Just a few genotypes of crop species have been used for gene modifications thus far. Nevertheless, in spite of the restrictions mentioned, essential success has been achieved over a short period (3.5 years since the first publications on CRISPR/Cas application in plants)

    Transformation of the reproduction of human capital in the context of the digital economy

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    The goal of the article is to study transformation processes and to identify the main characteristics of the reproduction of human capital in the context of digital and technological transformatio
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