202 research outputs found

    VirE2: A Unique ssDNA-Compacting Molecular Machine

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    The translocation of single-stranded DNA (ssDNA) across membranes of two cells is a fundamental biological process occurring in both bacterial conjugation and Agrobacterium pathogenesis. Whereas bacterial conjugation spreads antibiotic resistance, Agrobacterium facilitates efficient interkingdom transfer of ssDNA from its cytoplasm to the host plant cell nucleus. These processes rely on the Type IV secretion system (T4SS), an active multiprotein channel spanning the bacterial inner and outer membranes. T4SSs export specific proteins, among them relaxases, which covalently bind to the 5' end of the translocated ssDNA and mediate ssDNA export. In Agrobacterium tumefaciens, another exported protein—VirE2—enhances ssDNA transfer efficiency 2000-fold. VirE2 binds cooperatively to the transferred ssDNA (T-DNA) and forms a compact helical structure, mediating T-DNA import into the host cell nucleus. We demonstrated—using single-molecule techniques—that by cooperatively binding to ssDNA, VirE2 proteins act as a powerful molecular machine. VirE2 actively pulls ssDNA and is capable of working against 50-pN loads without the need for external energy sources. Combining biochemical and cell biology data, we suggest that, in vivo, VirE2 binding to ssDNA allows an efficient import and pulling of ssDNA into the host. These findings provide a new insight into the ssDNA translocation mechanism from the recipient cell perspective. Efficient translocation only relies on the presence of ssDNA binding proteins in the recipient cell that compacts ssDNA upon binding. This facilitated transfer could hence be a more general ssDNA import mechanism also occurring in bacterial conjugation and DNA uptake processes

    CMS physics technical design report : Addendum on high density QCD with heavy ions

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    A Roadmap for HEP Software and Computing R&D for the 2020s

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    Particle physics has an ambitious and broad experimental programme for the coming decades. This programme requires large investments in detector hardware, either to build new facilities and experiments, or to upgrade existing ones. Similarly, it requires commensurate investment in the R&D of software to acquire, manage, process, and analyse the shear amounts of data to be recorded. In planning for the HL-LHC in particular, it is critical that all of the collaborating stakeholders agree on the software goals and priorities, and that the efforts complement each other. In this spirit, this white paper describes the R&D activities required to prepare for this software upgrade.Peer reviewe

    Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

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    A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació

    stairs and fire

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    Dissertatio Medica Inavgvralis, De Aphthis

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    Quam Præside Supremo Numine, Consensv Et Avctoritate Magnifici & Gratiosißimi Medicorum Ordinis In celebri & perantiqua Ravracorvm Academia, Pro summis in Artis Medicæ Honoribus & Privilegiis Doctoralibus Legitimè capessendis, Publico Examini submittit Jacobvs Hegnervs, Helveto-Vitoduranus. Ad Diem ... Februarii Anno MDCCIV. H.L.Q.S.Enthält 32 ThesenDruckvariante 2Zwei Druckvarianten: Variante 1: Titelblatt verso blank, Variante 2: Titelblatt verso mit Widmung "Viris Vrbis Vitoduranæ Inclytæ ... Dn. Johanni Steinero, ..."Datum auf Titelblatt handschriftlich ergänzt: "26"Dissertation Medizinische Fakultät der Universität Basel 170

    De indicatione vitali et remediis huic satisfacientibus

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    quam ... pro summis in medicina honoribus atque privilegiis doctoralibus legitime impetrandis publico eruditorum examini submittit Ioh. Iacobus Hegner, Vitoduranus. Ad diem 20. Maii, M D C C XLVI. ...Enthält 27 ThesenDiss. med. Univ. Basel, 174

    Stoicheiologian Ad Helvetiam Applicatam

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    Search for narrow resonances using the dijet mass spectrum in pp collisions at s√=8  TeV

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    Results are presented of a search for the production of new particles decaying to pairs of partons (quarks, antiquarks, or gluons), in the dijet mass spectrum in proton-proton collisions at s√=8  TeV. The data sample corresponds to an integrated luminosity of 4.0  fb−1, collected with the CMS detector at the LHC in 2012. No significant evidence for narrow resonance production is observed. Upper limits are set at the 95% confidence level on the production cross section of hypothetical new particles decaying to quark-quark, quark-gluon, or gluon-gluon final states. These limits are then translated into lower limits on the masses of new resonances in specific scenarios of physics beyond the standard model. The limits reach up to 4.8 TeV, depending on the model, and extend previous exclusions from similar searches performed at lower collision energies. For the first time mass limits are set for the Randall–Sundrum graviton model in the dijet channel

    DMSO Chemically Alters Cell Membranes to Slow Exocytosis and Increase the Fraction of Partial Transmitter Released

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    Dimethyl sulfoxide (DMSO) is frequently used as a solvent in biological studies and as a vehicle for drug therapy; but the side effects of DMSO, especially on the cell environment, are not well understood, and controls with DMSO are not neutral at higher concentrations. Herein, electrochemical measurement techniques are applied to show that DMSO increases exocytotic neurotransmitter release, while leaving vesicular contents unchanged. In addition, the kinetics of release from DMSOtreated cells are faster than that of untreated ones. The results suggest that DMSO has a significant influence on the chemistry of the cell membrane, leading to alteration of exocytosis. A speculative chemical mechanism of the effect on the fusion pore during exocytosis is presented
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