Evolution, Composition and Regulation of Supernumerary B Chromosomes

Supernumerary B chromosomes (Bs) are dispensable genetic elements found in thousands of species of plants and animals, and some fungi [...

Sustainable development of education: mutual links of technology and pedagogy

Целью работы является сопоставление трендов развития информационно-коммуникационной среды, глобального образовательного пространства и педагогических идей, явно или опосредованно влияющих на применение ИКТ в образовании. Материалом послужили результаты форсайтов и содержание публикаций в интернете, посвященных перспективам устойчивого развития образования в контексте Инчхонской Декларации ЮНЕСКО «Образование 2030». На основе контент-анализа педагогических публикаций установлено, что современное понимание знания апеллирует к его обобществлению и распространению в глобальной сетевой информационной среде, технологический базис которой стремительно развивается. Учебный процесс в обществе обучения рассматривается как распределенный среди отдельных формальных учебных заведений («университетов мира для одного») и сообществом контента кураторов, в функции которого входит поставлять комментарии, обобщать и содействовать новой информации, которая поддерживает неоформальные образовательные потребности различных пользователей глобальной сети. Описана модель связей субъектов информационного образовательного пространства, включающая кроме преподавателей и студентов также кураторов контента. Аргументирована необходимость развития гуманитарного потенциала человека в информационно-коммуникационной среде и формирования в ней креативного класса людей, делящихся своим экзистенциональным опытом, знаниями и мудростью. Сделан вывод, что без межличностного взаимодействия, без присутствия учащихся в сетевом сообществе, развитие потенциала каждого члена общества в роботизированной среде искусственного интеллекта будет ущербным. Поэтому, в развитии аппаратной и программной базы технологий образования необходимо учитывать психолого-педагогические теории коннективизма, социального обучения, множественного интеллекта и других. The purpose of the paper is to compare the development trends of information and communication environment, the global educational space and pedagogical ideas, which directly or indirectly affect the application of ICT in education. The study has been based on the foresight results and the content of the Internet publications on the prospects for sustainable development of education in the context of UNESCO Incheon Declaration for Education 2030. The content analysis of pedagogical publications has demonstrated that the current understanding of knowledge appeals to its socialization and dissemination in the global network environment, whose technological basis is rapidly growing. The educational process in the Learning Society is regarded as a distributed one among some formal education establishments (“universities of the world for one”) and the community of content curators. The function of content curators is to deliver comments, generalize and promote new information that supports learning needs of different global network users. The relation model of the subjects of the informational and educational space has been described. The model includes lecturers and learners as well as the content curators. The necessity of humanitarian potential development in the informational and communicational environment has been argued as well as the development of a creative class of people who share their existential experience, knowledge and wisdom. The development of every society member in the robot-based artificial intelligence environment has been considered to be defective without any interpersonal interaction and learners’ activity in the online community. Thus, the psychological and pedagogical theories of connectionism, social learning, multiple intelligences, and some others are to be recognized in the development of hardware and software base for education technologies

Effect of nanosized filler on mechanical properties of epoxy compositesafter electron irradiation

Введение нанодисперсных наполнителей в полимеры является перспективным способом получения материалов с улучшенными характеристиками и может способствовать повышению радиационнойстойкости. В данной работе приготовлены образцы из эпоксидной смолы без наполнителя и с наполнителем - нанодисперсным алюминием (0,35 мас. %).Изучены механические характеристики образцов после облучения потоком электронов дозами 30, 100 и 300 кГр. Введение нанопорошка алюминия в эпоксидную смолу привело к повышению устойчивости полимера к радиационному воздействию.The introduction of nanosized fillers in polymers is a promising way to obtain materials with improvedproperties and can enhance the radiation resistance. In this study, the samples were prepared from the epoxy resinwithout filler and filled with nanodispersed aluminum (0.35 wt.%).The mechanical characteristics of the samplesafter irradiation with an electron beam of doses 30, 100 and 300 kGy were studied. The introduction of aluminumnanopowder in epoxy resin resulted in increased resistance to radiation

Cytogenetic Characterization of the TM4 Mouse Sertoli Cell Line. II. Chromosome Microdissection, FISH, Scanning Electron Microscopy, and Confocal Laser Scanning Microscopy

The chromosomes and interphase cell nuclei of the permanent mouse Sertoli cell line TM4 were examined by chromosome microdissection, FISH, scanning electron microscopy, and confocal laser scanning microscopy. The already known marker chromosomes m1-m5 were confirmed, and 2 new large marker chromosomes m6 and m7 were characterized. The minute heterochromatic marker chromosomes m4 and m5 were microdissected and their DNA amplified by DOP-PCR. FISH of this DNA probe on TM4 metaphase chromosomes demonstrated that the m4 and m5 marker chromosomes have derived from the centromeric regions of normal telocentric mouse chromosomes. Ectopic pairing of the m4 and m5 marker chromosomes with the centromeric region of any of the other chromosomes (centromeric associations) was apparent in ∼60% of the metaphases. Scanning electron microscopy revealed DNA-protein bridges connecting the centromeric regions of normal chromosomes and the associated m4 and m5 marker chromosomes. Interphase cell nuclei of TM4 Sertoli cells did not exhibit the characteristic morphology of Sertoli cells in the testes of adult mice as shown by fluorescence microscopy and confocal laser scanning microscopy

Functional divergence of microtubule-associated TPX2 family members in Arabidopsis thaliana

TPX2 (Targeting Protein for Xklp2) is an evolutionary conserved microtubule-associated protein important for microtubule nucleation and mitotic spindle assembly. The protein was described as an activator of the mitotic kinase Aurora A in humans and the Arabidopsis AURORA1 (AUR1) kinase. In contrast to animal genomes that encode only one TPX2 gene, higher plant genomes encode a family with several TPX2-LIKE gene members (TPXL). TPXL genes of Arabidopsis can be divided into two groups. Group A proteins (TPXL2, 3, 4, and 8) contain Aurora binding and TPX2_importin domains, while group B proteins (TPXL1, 5, 6, and 7) harbor an Xklp2 domain. Canonical TPX2 contains all the above-mentioned domains. We confirmed using in vitro kinase assays that the group A proteins contain a functional Aurora kinase binding domain. Transient expression of Arabidopsis TPX2-like proteins in Nicotiana benthamiana revealed preferential localization to microtubules and nuclei. Co-expression of AUR1 together with TPX2-like proteins changed the localization of AUR1, indicating that these proteins serve as targeting factors for Aurora kinases. Taken together, we visualize the various localizations of the TPX2-LIKE family in Arabidopsis as a proxy to their functional divergence and provide evidence of their role in the targeted regulation of AUR1 kinase activity

Phosphorilation of histone H3 in plants - a dynamic affair

Histones are the main protein components of chromatin: they undergo extensive post-translational modifications, particularly acetylation, methylation, phosphorylation, ubiquitination and ADP-ribosylation which modify the structural/functional properties of chromatin. Posttranslational modifications of the N-terminal tails of the core histones within the nucleosome particle are thought to act as signals from the chromatin to the cell, for various processes. Thus, in many ways histone tails can be viewed as complex protein–protein interaction surfaces that are regulated by numerous post-translational modifications. Histone phosphorylation has been linked to chromosome condensation/segregation, activation of transcription, apoptosis and DNA damage repair. In plants, the cell cycle dependent phosphorylation of histone H3 has been described; it is hyperphosphorylated at serines 10/28 and at threonines 3/11 during both mitosis and meiosis in patterns that are specifically coordinated in both space and time. Although this post-translational modification is highly conserved, data show that the chromosomal distribution of individual modifications can differ between groups of eukaryotes. Initial results indicate that members of the plant Aurora kinase family have the capacity to control cell cycle regulated histone H3 phosphorylation, and in addition we describe other potential H3 kinases and discuss their functions

Quantum dots – a versatile tool in plant science?

An optically stable, novel class of fluorophores (quantum dots) for in situ hybridisation analysis was tested to investigate their signal stability and intensity in plant chromosome analyses. Detection of hybridisation sites in situ was based on fluorescence from streptavidin-linked inorganic crystals of cadmium selenide. Comparison of quantum dots (QDs) with conventional detection systems (Alexa 488) in immunolabeling experiments demonstrated greater sensitivity than the conventional system. In contrast, detection of QDs in in situ hybridisation of several plant chromosomes, using several high-copy sequences, was less sensitve than Alexa 488. Thus, semiconductor nanocrystal fluorophores are more suitable for immunostaining but not for in situ hybridisation of plant chromosomes

Changing local recombination patterns in Arabidopsis by CRISPR/Cas mediated chromosome engineering

Chromosomal inversions are recurrent rearrangements that occur between different plant isolates or cultivars. Such inversions may underlie reproductive isolation in evolution and represent a major obstacle for classical breeding as no crossovers can be observed between inverted sequences on homologous chromosomes. The heterochromatic knob (hk4S) on chromosome 4 is the most well-known inversion of Arabidopsis. If a knob carrying accession such as Col-0 is crossed with a knob-less accession such as Ler-1, crossovers cannot be recovered within the inverted region. Our work shows that by egg-cell specific expression of the Cas9 nuclease from Staphylococcus aureus, a targeted reversal of the 1.1 Mb long hk4S-inversion can be achieved. By crossing Col-0 harbouring the rearranged chromosome 4 with Ler-1, meiotic crossovers can be restored into a region with previously no detectable genetic exchange. The strategy of somatic chromosome engineering for breaking genetic linkage has huge potential for application in plant breeding

Transcriptionally active heterochromatin in rye B chromosomes

B chromosomes (Bs) are dispensable components of the genomes of numerous species. Thus far, there is a lack of evidence for any transcripts of Bs in plants, with the exception of some rDNA sequences. Here, we show that the Giemsa bandingpositive heterochromatic subterminal domain of rye (Secale cereale) Bs undergoes decondensation during interphase. Contrary to the heterochromatic regions of A chromosomes, this domain is simultaneously marked by trimethylated H3K4 and by trimethylated H3K27, an unusual combination of apparently conflicting histone modifications. Notably, both types of B-specific high copy repeat families (E3900 and D1100) of the subterminal domain are transcriptionally active, although with different tissue type–dependent activity. No small RNAs were detected specifically for the presence of Bs. The lack of any significant open reading frame and the highly heterogeneous size of mainly polyadenylated transcripts indicate that the noncoding RNA may function as structural or catalytic RNA