178 research outputs found

    Biosensor Based on Ultrasmall MoS2 Nanoparticles for Electrochemical Detection of H2O2 Released by Cells at the Nanomolar Level

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    Monodispersed surfactant-free MoS2 nanoparticles with sizes of less than 2 nm were prepared from bulk MoS2 by simple ultrasonication and gradient centrifugation. The ultrasmall MoS2 nanoparticles expose a large fraction of edge sites, along with their high surface area, which lead to attractive electrocatalytic activity for reduction of H2O2. An extremely sensitive H2O2 biosensor based on MoS2 nanoparticles with a real determination limit as low as 2.5 nM and wide linear range of 5 orders of magnitude was constructed. On the basis of this biosensor, the trace amount of H2O2 released from Raw 264.7 cells was successfully recorded, and an efficient glucose biosensor was also fabricated. Since H2O2 is a byproduct of many oxidative biological reactions, this work serves as a pathway for the application of MoS2 in the fields of electrochemical sensing and bioanalysis.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000326711400047&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, AnalyticalSCI(E)EIPubMed75ARTICLE2110289-102958

    Estimations of effectiveness of applications of the methods of lymphogeneous detoxication at a syndrome of abolition of opioids

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    The aim of this paper was an estimation of effectiveness of application of lymphotropic and ozone and lymphotropic and absorbtion technologies at a syndrome of abolition of opioids. The object of research was 142 patients distributed in three homogeneous groups. The control group has been got the standard therapy, the main first group - additionally to it - a complex of lymphotropic therapy and ozone therapy, the main second group - a complex of lymphotropic therapy and enteroabsorbtion. The comparative estimation of the results has shown that the lymhotropic and ozone technology has influenced more actively on the parameters of immune system and syndrome of labilization of the cellular membranes, the lymphotropic and absorbtion technology - on a purification of organism from endogeneous metabolits. The purposive combination of lymphotropic therapy and ozone therapy and enteroabsorbtion taking into account the leading mechanisms of endotoxemia, allows to provide the effective correction of endogeneous intoxication and improve a quality of standard therapy significantly.Цель работы: Целью работы настоящей явилась оценка эффективности применения лимфотропно-озоновой и лимфотропно-сорбционной технологий при синдроме отмены опиоидов. Объектом исследования явились 142 больных, распределенных на три однородные группы. Контрольная группа получала стандартную терапию, 1 -я основная дополнительно к ней комплекс лимфотропной терапии и озонотерапии, 2-я основная - лимфотропной терапии и энтеросорбции. Сравнительная оценка полученных результатов показала, что лимфотропно-озоновая технология боле активно влияла на параметры иммунной системы и синдрома лабилизации клеточных мембран, лимфотропно-сорбционная технология - на очищение организма от эндогенных метаболитов. Целенаправленное сочетание лимфотропной терапии с озонотерапией и энтеросорбцией, учитывающее ведущие механизмы эндотоксемии, позволяет обеспечить эффективную коррекцию эндогенной интоксикации и существенно улучшить качество патогенетической терапии

    Whacked and Rab35 polarize dynein-motor-complex-dependent seamless tube growth

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    Seamless tubes form intracellularly without cell–cell or autocellular junctions. Such tubes have been described across phyla, but remain mysterious despite their simple architecture. In Drosophila, seamless tubes are found within tracheal terminal cells, which have dozens of branched protrusions extending hundreds of micrometres. We find that mutations in multiple components of the dynein motor complex block seamless tube growth, raising the possibility that the lumenal membrane forms through minus-end-directed transport of apical membrane components along microtubules. Growth of seamless tubes is polarized along the proximodistal axis by Rab35 and its apical membrane-localized GAP, Whacked. Strikingly, loss of whacked (or constitutive activation of Rab35) leads to tube overgrowth at terminal cell branch tips, whereas overexpression of Whacked (or dominant-negative Rab35) causes formation of ectopic tubes surrounding the terminal cell nucleus. Thus, vesicle trafficking has key roles in making and shaping seamless tubes

    Intracellular lumen extension requires ERM-1-dependent apical membrane expansion and AQP-8-mediated flux

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    SUMMARY Many unicellular tubes such as capillaries form lumens intracellularly, a process that is not well understood. Here we show that the cortical membrane organizer ERM-1 is required to expand the intracellular apical/lumenal membrane and its actin undercoat during single-cell C.elegans excretory canal morphogenesis. We characterize AQP-8, identified in an ERM-1 overexpression (ERM-1[++]) suppressor screen, as a canalicular aquaporin that interacts with ERM-1 in lumen extension in a mercury-sensitive manner, implicating water-channel activity. AQP-8 is transiently recruited to the lumen by ERM-1, co-localizing in peri-lumenal cuffs interspaced along expanding canals. An ERM-1[++]-mediated increase in the number of lumen-associated canaliculi is reversed by AQP-8 depletion. We propose that the ERM-1-AQP-8 interaction propels lumen extension by translumenal flux, suggesting a direct morphogenetic effect of water-channel-regulated fluid pressure

    γCOP Is Required for Apical Protein Secretion and Epithelial Morphogenesis in Drosophila melanogaster

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    Background: There is increasing evidence that tissue-specific modifications of basic cellular functions play an important role in development and disease. To identify the functions of COPI coatomer-mediated membrane trafficking in Drosophila development, we were aiming to create loss-of-function mutations in the γCOP gene, which encodes a subunit of the COPI coatomer complex. Principal Findings: We found that γCOP is essential for the viability of the Drosophila embryo. In the absence of zygotic γCOP activity, embryos die late in embryogenesis and display pronounced defects in morphogenesis of the embryonic epidermis and of tracheal tubes. The coordinated cell rearrangements and cell shape changes during tracheal tube morphogenesis critically depend on apical secretion of certain proteins. Investigation of tracheal morphogenesis in γCOP loss-of-function mutants revealed that several key proteins required for tracheal morphogenesis are not properly secreted into the apical lumen. As a consequence, γCOP mutants show defects in cell rearrangements during branch elongation, in tube dilation, as well as in tube fusion. We present genetic evidence that a specific subset of the tracheal defects in γCOP mutants is due to the reduced secretion of the Zona Pellucida protein Piopio. Thus, we identified a critical target protein of COPI-dependent secretion in epithelial tube morphogenesis. Conclusions/Significance: These studies highlight the role of COPI coatomer-mediated vesicle trafficking in both general and tissue-specific secretion in a multicellular organism. Although COPI coatomer is generally required for protein secretion, we show that the phenotypic effect of γCOP mutations is surprisingly specific. Importantly, we attribute a distinct aspect of the γCOP phenotype to the effect on a specific key target protein

    A Systematic Screen for Tube Morphogenesis and Branching Genes in the Drosophila Tracheal System

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    Many signaling proteins and transcription factors that induce and pattern organs have been identified, but relatively few of the downstream effectors that execute morphogenesis programs. Because such morphogenesis genes may function in many organs and developmental processes, mutations in them are expected to be pleiotropic and hence ignored or discarded in most standard genetic screens. Here we describe a systematic screen designed to identify all Drosophila third chromosome genes (∼40% of the genome) that function in development of the tracheal system, a tubular respiratory organ that provides a paradigm for branching morphogenesis. To identify potentially pleiotropic morphogenesis genes, the screen included analysis of marked clones of homozygous mutant tracheal cells in heterozygous animals, plus a secondary screen to exclude mutations in general “house-keeping” genes. From a collection including more than 5,000 lethal mutations, we identified 133 mutations representing ∼70 or more genes that subdivide the tracheal terminal branching program into six genetically separable steps, a previously established cell specification step plus five major morphogenesis and maturation steps: branching, growth, tubulogenesis, gas-filling, and maintenance. Molecular identification of 14 of the 70 genes demonstrates that they include six previously known tracheal genes, each with a novel function revealed by clonal analysis, and two well-known growth suppressors that establish an integral role for cell growth control in branching morphogenesis. The rest are new tracheal genes that function in morphogenesis and maturation, many through cytoskeletal and secretory pathways. The results suggest systematic genetic screens that include clonal analysis can elucidate the full organogenesis program and that over 200 patterning and morphogenesis genes are required to build even a relatively simple organ such as the Drosophila tracheal system
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