Digital transformation of general education–some problems and risks of the current stage of implementation

Статья посвящена анализу текста стратегии «Цифровая трансформация образования». Отмечаются концептуальные недостатки в оценке и учете результатов предшествующих этапов цифровизации, отсутствие научного осмысления текущих проблем. Приводятся примеры противоречий между различными регламентирующими документами, расхождения межу целями и результатами текущего этапа цифровой трансформации образования. Отмечаются некоторые риски, неучтённые при разработке стратегии.The article is devoted to the analysis of the text of the strategy "Digital transformation of education". There are conceptual shortcomings in assessing and taking into account the results of previous stages of digitalization, the lack of scientific understanding of current problems. Examples of contradictions between various regulatory documents, discrepancies between the goals and results of the current stage of the digital transformation of education are given. There are some risks that are not taken into account when developing a strategy

Practical and reliable FRET/FLIM pair of fluorescent proteins

Background: In spite of a great number of monomeric fluorescent proteins developed in the recent years, the reported fluorescent protein-based FRET pairs are still characterized by a number of disadvantageous features, complicating their use as reporters in cell biology and for high-throughput cell-based screenings. Results: Here we screened some of the recently developed monomeric protein pairs to find the optimal combination, which would provide high dynamic range FRET changes, along with high pH- and photo-stability, fast maturation and bright fluorescence, and reliable detection in any fluorescent imaging system. Among generated FRET pairs, we have selected TagGFP-TagRFP, combining all the mentioned desirable characteristics. On the basis of this highly efficient FRET pair, we have generated a bright, high contrast, pH- and photo-stable apoptosis reporter, named CaspeR3 (Caspase 3 Reporter). Conclusion: The combined advantages suggest that the TagGFP-TagRFP is one of the most efficient green/red couples available to date for FRET/FLIM analyses to monitor interaction of proteins of interest in living cells and to generate FRET-based sensors for various applications. CaspeR3 provides reliable detection of apoptosis, and should become a popular tool both for cell biology studies and high throughput screening assays

Conversion of red fluorescent protein into a bright blue probe

We used a red chromophore formation pathway, in which the anionic red chromophore is formed from the neutral blue intermediate, to suggest a rational design strategy to develop blue fluorescent proteins with a tyrosine-based chromophore. The strategy was applied to red fluorescent proteins of the different genetic backgrounds, such as TagRFP, mCherry, HcRed1, M355NA, and mKeima, which all were converted into blue probes. Further improvement of the blue variant of TagRFP by random mutagenesis resulted in an enhanced monomeric protein, mTagBFP, characterized by the substantially higher brightness, the faster chromophore maturation, and the higher pH stability than blue fluorescent proteins with a histidine in the chromophore. The detailed biochemical and photochemical analysis indicates that mTagBFP is the true monomeric protein tag for multicolor and lifetime imaging, as well as the outstanding donor for green fluorescent proteins in Forster resonance energy transfer applications

The Structure of Ca2+ Sensor Case16 Reveals the Mechanism of Reaction to Low Ca2+ Concentrations

Here we report the first crystal structure of a high-contrast genetically encoded circularly permuted green fluorescent protein (cpGFP)-based Ca2+ sensor, Case16, in the presence of a low Ca2+ concentration. The structure reveals the positioning of the chromophore within Case16 at the first stage of the Ca2+-dependent response when only two out of four Ca2+-binding pockets of calmodulin (CaM) are occupied with Ca2+ ions. In such a “half Ca2+-bound state”, Case16 is characterized by an incomplete interaction between its CaM-/M13-domains. We also report the crystal structure of the related Ca2+ sensor Case12 at saturating Ca2+ concentration. Based on this structure, we postulate that cpGFP-based Ca2+ sensors can form non-functional homodimers where the CaM-domain of one sensor molecule binds symmetrically to the M13-peptide of the partner sensor molecule. Case12 and Case16 behavior upon addition of high concentrations of free CaM or M13-peptide reveals that the latter effectively blocks the fluorescent response of the sensor. We speculate that the demonstrated intermolecular interaction with endogenous substrates and homodimerization can impede proper functioning of this type of Ca2+ sensors in living cells

Single fluorescent protein-based Ca2+ sensors with increased dynamic range

<p>Abstract</p> <p>Background</p> <p>Genetically encoded sensors developed on the basis of green fluorescent protein (GFP)-like proteins are becoming more and more popular instruments for monitoring cellular analytes and enzyme activities in living cells and transgenic organisms. In particular, a number of Ca²⁺sensors have been developed, either based on FRET (Fluorescence Resonance Energy Transfer) changes between two GFP-mutants or on the change in fluorescence intensity of a single circularly permuted fluorescent protein (cpFP).</p> <p>Results</p> <p>Here we report significant progress on the development of the latter type of Ca²⁺sensors. Derived from the knowledge of previously reported cpFP-based sensors, we generated a set of cpFP-based indicators with different spectral properties and fluorescent responses to changes in Ca²⁺concentration. Two variants, named Case12 and Case16, were characterized by particular high brightness and superior dynamic range, up to 12-fold and 16.5-fold increase in green fluorescence between Ca²⁺-free and Ca²⁺-saturated forms. We demonstrated the high potential of these sensors on various examples, including monitoring of Ca²⁺response to a prolonged glutamate treatment in cortical neurons.</p> <p>Conclusion</p> <p>We believe that expanded dynamic range, high brightness and relatively high pH-stability should make Case12 and Case16 popular research tools both in scientific studies and high throughput screening assays.</p

Long-term (trophic) purinergic signalling: purinoceptors control cell proliferation, differentiation and death

The purinergic signalling system, which uses purines and pyrimidines as chemical transmitters, and purinoceptors as effectors, is deeply rooted in evolution and development and is a pivotal factor in cell communication. The ATP and its derivatives function as a 'danger signal' in the most primitive forms of life. Purinoceptors are extraordinarily widely distributed in all cell types and tissues and they are involved in the regulation of an even more extraordinary number of biological processes. In addition to fast purinergic signalling in neurotransmission, neuromodulation and secretion, there is long-term (trophic) purinergic signalling involving cell proliferation, differentiation, motility and death in the development and regeneration of most systems of the body. In this article, we focus on the latter in the immune/defence system, in stratified epithelia in visceral organs and skin, embryological development, bone formation and resorption, as well as in cancer. Cell Death and Disease (2010) 1, e9; doi:10.1038/cddis.2009.11; published online 14 January 201

Ion access pathway to the transmembrane pore in P2X receptor channels

P2X receptors are trimeric cation channels that open in response to the binding of adenosine triphosphate (ATP) to a large extracellular domain. The x-ray structure of the P2X4 receptor from zebrafish (zfP2X4) receptor reveals that the extracellular vestibule above the gate opens to the outside through lateral fenestrations, providing a potential pathway for ions to enter and exit the pore. The extracellular region also contains a void at the central axis, providing a second potential pathway. To investigate the energetics of each potential ion permeation pathway, we calculated the electrostatic free energy by solving the Poisson-Boltzmann equation along each of these pathways in the zfP2X4 crystal structure and a homology model of rat P2X2 (rP2X2). We found that the lateral fenestrations are energetically favorable for monovalent cations even in the closed-state structure, whereas the central pathway presents strong electrostatic barriers that would require structural rearrangements to allow for ion accessibility. To probe ion accessibility along these pathways in the rP2X2 receptor, we investigated the modification of introduced Cys residues by methanethiosulfonate (MTS) reagents and constrained structural changes by introducing disulfide bridges. Our results show that MTS reagents can permeate the lateral fenestrations, and that these become larger after ATP binding. Although relatively small MTS reagents can access residues in one of the vestibules within the central pathway, no reactive positions were identified in the upper region of this pathway, and disulfide bridges that constrain movements in that region do not prevent ion conduction. Collectively, these results suggest that ions access the pore using the lateral fenestrations, and that these breathe as the channel opens. The accessibility of ions to one of the chambers in the central pathway likely serves a regulatory function