138 research outputs found
Improved detection of differentially represented DNA barcodes for high-throughput clonal phenomics
Cellular DNA barcoding has become a popular approach to study heterogeneity of cell populations and to identify clones with differential response to cellular stimuli. However, there is a lack of reliable methods for statistical inference of differentially responding clones. Here, we used mixtures of DNA-barcoded cell pools to generate a realistic benchmark read count dataset for modelling a range of outcomes of clone-tracing experiments. By accounting for the statistical properties intrinsic to the DNA barcode read count data, we implemented an improved algorithm that results in a significantly lower false-positive rate, compared to current RNA-seq data analysis algorithms, especially when detecting differentially responding clones in experiments with strong selection pressure. Building on the reliable statistical methodology, we illustrate how multidimensional phenotypic profiling enables one to deconvolute phenotypically distinct clonal subpopulations within a cancer cell line. The mixture control dataset and our analysis results provide a foundation for benchmarking and improving algorithms for clone-tracing experiments
Principles and methods of comparative analysis of artistic concepts by future artist-teachers
The article presents an example of the implementation of an independent art history analysis of the work of three different artists, who, despite the external differences, have a certain similarity in the creative pictorial concept. Attention is drawn to the importance of the issue of improving the skills of the future teacher of the fine arts using art historical analysis. The main research methods are the study of art history materials, methods of comparative analysis, deduction, theoretical and methodological approaches. Based on the research within the framework of the article, it was concluded that comparative art history analysis is part of the creative process on the path of improving the future teacher. The article is recommended for bachelors and undergraduates of artistic and pedagogical directions.Осуществлен самостоятельный искусствоведческий анализ творчества трех разных художников, имеющих, несмотря на внешние различия, определенную схожесть в творческой живописной концепции. Обращается внимание на важность совершенствования мастерства будущего педагога изобразительного искусства посредством проведения искусствоведческого анализа. Основные методы исследования - изучение соответствующих материалов, методы сравнительного анализа, дедукции, теоретико-методологические подходы. На основе исследования в рамках статьи сделан вывод о том, что сравнительный искусствоведческий анализ - часть творческого процесса на пути совершенствования будущего педагога. Статья рекомендована бакалаврам и магистрантам художественно-педагогических направлений
Primary carbonatite melt from deeply subducted oceanic crust
Partial melting in the Earth's mantle plays an important part in generating the geochemical and isotopic diversity observed in volcanic rocks at the surface. Identifying the composition of these primary melts in the mantle is crucial for establishing links between mantle geochemical 'reservoirs' and fundamental geodynamic processes. Mineral inclusions in natural diamonds have provided a unique window into such deep mantle processes. Here we provide experimental and geochemical evidence that silicate mineral inclusions in diamonds from Juina, Brazil, crystallized from primary and evolved carbonatite melts in the mantle transition zone and deep upper mantle. The incompatible trace element abundances calculated for a melt coexisting with a calcium-titanium-silicate perovskite inclusion indicate deep melting of carbonated oceanic crust, probably at transition-zone depths. Further to perovskite, calcic-majorite garnet inclusions record crystallization in the deep upper mantle from an evolved melt that closely resembles estimates of primitive carbonatite on the basis of volcanic rocks. Small-degree melts of subducted crust can be viewed as agents of chemical mass-transfer in the upper mantle and transition zone, leaving a chemical imprint of ocean crust that can possibly endure for billions of years.4 page(s
The Second Transmembrane Domain of P2X7 Contributes to Dilated Pore Formation
Activation of the purinergic receptor P2X7 leads to the cellular permeability of low molecular weight cations. To determine which domains of P2X7 are necessary for this permeability, we exchanged either the C-terminus or portions of the second transmembrane domain (TM2) with those in P2X1 or P2X4. Replacement of the C-terminus of P2X7 with either P2X1 or P2X4 prevented surface expression of the chimeric receptor. Similarly, chimeric P2X7 containing TM2 from P2X1 or P2X4 had reduced surface expression and no permeability to cationic dyes. Exchanging the N-terminal 10 residues or C-terminal 14 residues of the P2X7 TM2 with the corresponding region of P2X1 TM2 partially restored surface expression and limited pore permeability. To further probe TM2 structure, we replaced single residues in P2X7 TM2 with those in P2X1 or P2X4. We identified multiple substitutions that drastically changed pore permeability without altering surface expression. Three substitutions (Q332P, Y336T, and Y343L) individually reduced pore formation as indicated by decreased dye uptake and also reduced membrane blebbing in response to ATP exposure. Three others substitutions, V335T, S342G, and S342A each enhanced dye uptake, membrane blebbing and cell death. Our results demonstrate a critical role for the TM2 domain of P2X7 in receptor function, and provide a structural basis for differences between purinergic receptors. © 2013 Sun et al
Neuroinflammation, Mast Cells, and Glia: Dangerous Liaisons
The perspective of neuroinflammation as an epiphenomenon following neuron damage is being replaced by the awareness of glia and their importance in neural functions and disorders. Systemic inflammation generates signals that communicate with the brain and leads to changes in metabolism and behavior, with microglia assuming a pro-inflammatory phenotype. Identification of potential peripheral-to-central cellular links is thus a critical step in designing effective therapeutics. Mast cells may fulfill such a role. These resident immune cells are found close to and within peripheral nerves and in brain parenchyma/meninges, where they exercise a key role in orchestrating the inflammatory process from initiation through chronic activation. Mast cells and glia engage in crosstalk that contributes to accelerate disease progression; such interactions become exaggerated with aging and increased cell sensitivity to stress. Emerging evidence for oligodendrocytes, independent of myelin and support of axonal integrity, points to their having strong immune functions, innate immune receptor expression, and production/response to chemokines and cytokines that modulate immune responses in the central nervous system while engaging in crosstalk with microglia and astrocytes. In this review, we summarize the findings related to our understanding of the biology and cellular signaling mechanisms of neuroinflammation, with emphasis on mast cell-glia interactions
Slab melting as a barrier to deep carbon subduction
Interactions between crustal and mantle reservoirs dominate the surface inventory of volatile elements over geological time, moderating atmospheric composition and maintaining a lifesupporting planet1. While volcanoes expel volatile components into surface reservoirs, subduction of oceanic crust is responsible for replenishment of mantle reservoirs2,3. Many natural, ‘superdeep’ diamonds originating in the deep upper mantle and transition zone host mineral inclusions, indicating an affinity to subducted oceanic crust4–7. Here we show that the majority of slab geotherms will intersect a deep depression along the melting curve of carbonated oceanic crust at depths of approximately 300 to 700 kilometres, creating a barrier to direct carbonate recycling into the deep mantle. Low-degree partial melts are alkaline carbonatites that are highly reactive with reduced ambient mantle, producing diamond. Many inclusions in superdeep diamonds are best explained by carbonate melt–peridotite reaction. A deep carbon barrier may dominate the recycling of carbon in the mantle and contribute to chemical and isotopic heterogeneity of the mantle reservoir
Micro-Raman study of crichtonite group minerals enclosed into mantle garnet
We report the first comprehensive micro-Raman study of crichtonite group minerals (CGM) as inclusions in pyropic garnet grains from peridotite and pyroxenite mantle xenoliths of the Yakutian kimberlites as well as in garnet xenocrysts from the Aldan shield lamprophyres (Russia). The CGM form (i) morphologically oriented needles, lamellae, and short prisms and (ii) optically unoriented subhedral to euhedral grains, either single or intergrown with other minerals. We considered common mantle-derived CGM species (like loveringite, lindsleyite, and their analogues), with Ca, Ba, or Sr dominating in the dodecahedral A site and Zr or Fe in the octahedral B site. The Raman bands at the region of 600–830 cm−1 are indicative of CGM and their crystal-chemical distinction, although the intensity and shape of the bands appear to be dependent on laser beam power and wavelength. The factor-group analysis based on the loveringite crystal structure showed the octahedral and tetrahedral cation groups with 18f and 6c Wyckoff positions, namely, dominantly TiO6 and to a lower extent CrO6, MgO4, and FeO4 groups, to be the major contributors to the Raman spectral features. The ionic groups with dodecahedral (M0) and octahedral (M1) coordination are inactive for Raman scattering while active in infrared absorption. A number of observed Raman modes in the CGM spectra are several times lower than that predicted by the factor group analysis. The noticed broadening of modes in the CGM Raman spectra may result from a combining of bands at the narrow frequency shift regions. Solid solution behavior, luminescence, and partial metamictization of the CGM may exert additional influence on the Raman band shape. The Raman spectral features showed CGM to be accurately identified and distinguished from other Ti-, Fe-, Cr-, and Zr-containing oxides (e.g., ilmenite or those of spinel and magnetoplumbite groups) occurring as accessory mantle minerals. © 2020 The Authors. Journal of Raman Spectroscopy published by John Wiley & Sons LtdRussian Science Foundation, RSF: 18‐77‐10062Council on grants of the President of the Russian FederationThis study was supported by the Russian Science Foundation (Grant 18‐77‐10062). The equipment of the Ural Center for Shared Use «Modern Nanotechnology», Ural Federal University, and the Analytical Center for Multi‐elemental and Isotope Research, IGM, was used. Sampling was supported by the Russian Federation state assignment project of IGM. We are grateful to Nikolai V. Sobolev for Samples O‐173, O‐39, and O‐264. Vladimir N. Korolyuk, Elena N. Nigmatulina (IGM), and Allan Patchen (UT) are highly appreciated for the help with EMP analyses. We express our sincere thanks to F. Nestola and an anonymous reviewer for their thorough reviews and helpful suggestions, and to C. Marshall for regardful editorial handling of the manuscript on every stage of its revision
Antiviral Properties of Chemical Inhibitors of Cellular Anti-Apoptotic Bcl-2 Proteins
Viral diseases remain serious threats to public health because of the shortage of effective means of control. To combat the surge of viral diseases, new treatments are urgently needed. Here we show that small-molecules, which inhibit cellular anti-apoptotic Bcl-2 proteins (Bcl-2i), induced the premature death of cells infected with different RNA or DNA viruses, whereas, at the same concentrations, no toxicity was observed in mock-infected cells. Moreover, these compounds limited viral replication and spread. Surprisingly, Bcl-2i also induced the premature apoptosis of cells transfected with viral RNA or plasmid DNA but not of mock-transfected cells. These results suggest that Bcl-2i sensitizes cells containing foreign RNA or DNA to apoptosis. A comparison of the toxicity, antiviral activity, and side effects of six Bcl-2i allowed us to select A-1155463 as an antiviral lead candidate. Thus, our results pave the way for the further development of Bcl-2i for the prevention and treatment of viral diseases.Peer reviewe
An oribatid mite (Arachnida: Acari) from the Oxford Clay (Jurassic: Upper Callovian) of South Cave Station Quarry, Yorkshire, UK
A single specimen of a new species of oribatid mite belonging to the genus Jureremus Krivolutsky, in Krivolutsky and Krassilov 1977, previously described from the Upper Jurassic of the Russian Far East, is described as J. phippsi sp. nov. The mite is preserved by iron pyrite replacement, and was recovered by sieving from the Oxford Clay
Formation (Jurassic: Upper Callovian) of South Cave, Yorkshire. It is the first record of a pre-Pleistocene mite, and the second species record of the family Cymbaeremaeidae, from the British Isles; also, it is only the third record of Acari from the Jurassic Period. The presence of a terrestrial mite in a sedimentary sequence of open marine origin is noteworthy, and suggestions for its mode of transport to the site of deposition are discussed
ОСОБЕННОСТИ СВЯЗЫВАНИ Я БИС -(3′,5′)-ЦИКЛИЧЕСКОГО ДИМЕРНОГО ГУАНОЗИНМОНОФОСФАТА С ТЕТРАМЕРАМИ ГЕМОГЛОБИНА ЧЕЛОВЕКА
Molecular modeling complexes of bis-(3′, 5′)-cyclic dimeric guanosine monophosphate (c-di-GMP) with human oxyhemoglobin HbA1 and the analysis of the cyclic diguanylic acid inhibitory effect on the binding of 1,8-ANS to HbA1 carried out by the steady-state fluorescence spectroscopy showed that the most specific binding site of c-di-GMP in hemoglobin oligomers is the central regulatory region of this protein (competitive inhibition constant is 2.91 ± 0.54·10−5 М). At high concentrations of 1,8-ANS c-di-GMP inhibitory effect on the probe binding is non-competitive (non-competitive inhibition constant is 0.79 ± 0.11·10−4 М), indicating the ability of c-di-GMP interact with less specific surface areas of human oxyhemoglobin.Молекулярные модели комплексов бис-(3′,5′)-циклического димерного гуанозинмонофосфата (c-di-GMP) с гемоглобином человека в R-состоянии показали, что c-di-GMP связывается с тетрамерами гемоглобина со стороны b-входа в центральную полость гемопротеида в DPG-связующем сайте белка.Анализ ингибирующего действия дигуанилата на связывание 1,8-ANS с тетрамерами гемопротеида, выполненный методом стационарной флуоресцентной спектроскопии, показал, что наиболее специфическим сайтом связывания c-di-GMP в олигомерах данного белка является его центральная регуляторная область (константа конкурентного ингибирования 2,91 ± 0,54·10−5 М). При высоких концентрациях 1,8-ANS ингибирующее действие циклического дигуанилата на связывание зонда становится неконкурентным (константа для неконкурентного ингибирования 0,79 ± 0,11·10−4 М), указывая на способность c-di-GMP взаимодействовать и с менее специфическими поверхностными участками оксигемоглобина человека
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