211,291 research outputs found
YscP, a key player in the type three secretion system of "Yersinia enterocolitica"
No full textThe Yersinia injectisome needle has a constant length of around 60nm. Mutants affected in the yscP gene display abnormally long needles, suggesting that needle length is genetically controlled and that YscP is involved in this process. First, both N- and C-term of YscP were shown to be required for proper needle length control. In contrast, the central part could be shortened or lengthened without loss of function, but giving a needle length strictly proportional to the number of residues of YscP. This led us to assign the function of a ruler to YscP. In addition to its role in the determination of the needles length, YscP is required for Yop secretion. The C-term part of YscP, required for proper needle length control, was shown to be also crucial for Yop secretion. Thus it is probably involved in the substrate-specificity switch of the machinery, from the needle component YscF to Yops. The study of this region by Hydrophobic Cluster Analysis led to a characterization of a new domain that we called T3S4 (TypeSecretion SubstrateSpecificity Switch) and which can be found in all counterparts of YscP in other injectisomes but also in flagellum. The conservation of the T3S4 structure suggests a similar function for all these proteins. The T3S4 domains found in injectisomes happened to be partially exchangeable. The overall structure of the domain seems to be the critical point. This is further supported by the fact that single alaninereplacement of the few conserved amino acids not affecting the structure, did not impact the functions. Since YscP is secreted by the injectisome, we analyzed whether its export is necessary for its functions. Two original export signals were found in YscP: one in the N-term (aa 1-35) and one more central (aa 97-137). These two signals exactly correspond to the N-term regions involved in needle length control. When YscP is deprived from its export signals, it still switches the substrate specificity but it cannot control needle length any more. These data suggest a model in which YscP export is linked to needle length control. Having evolved such a complex process for length control stresses the necessity of a certain length. Indeed, the length has evolved to match specific structures at the bacterial and host cell surfaces
Biological Carbon Sequestration and Carbon Trading Re-Visited
No full textUnder Kyoto, biological activities that sequester carbon can be used to create CO2 offset credits that could obviate the need for lifestyle-changing reductions in fossil fuel use. Credits are earned by storing carbon in terrestrial ecosystems and wood products, although CO2 emissions are also mitigated by delaying deforestation, which accounts for one-quarter of anthropogenic CO2 emissions. However, nonpermanent carbon offsets from biological activities are difficult to compare with each other and with emissions reduction because they differ in how long they prevent CO2 from entering the atmosphere. This is the duration problem; it results in uncertainty and makes it difficult to determine the legitimacy of biological activities in mitigating climate change. While there is not doubt that biological sink activities help mitigate climate change and should not be neglected, in this paper we demonstrate that these activities cannot be included in carbon trading schemes.carbon offset credits, climate change, duration of carbon sinks, Environmental Economics and Policy,
The discovery of SycO reveals a new function for type three secretion effector chaperones
No full textThe Type Three Secretion (T3S) system is a device used by many Gram-negative pathogens that allows bacteria to deliver effector proteins straight into the eukaryotic cell cytosol. These effectors interfere with various signaling pathways to subvert the host cell functions. The secretion machinery of the T3S system consist of a basal body spanning the bacterial inner and outer membrane followed by a stiff hollow needle outside the bacterium. The fully assembled secretion apparatus constitute a continuous hollow conduit that connects the bacteria to the eukaryotic target cell. After cell contact, virulence proteins -called effectors- are injected directly into the cytosol of the host cell via the T3S apparatus. Several effectors of the T3S system require the assistance of specific cytosolic chaperones to be efficiently exported. There are three classes of T3S chaperones. Effector proteins are assisted by Class I chaperones. Although Class I chaperones are well characterized, their main function is still a matter of controversy. In this thesis, we demonstrate that orf155 encodes a specific chaperone for the effector YopO that we called SycO. We showed that SycO enhances YopO secretion in vitro and is required for translocation of YopO into infected cells. By pulldown assay we demonstrated that residues 20 to 77 of YopO are required and sufficient for SycO binding. Using crosslinking experiments and size exclusion chromatography analysis, we determined the stoichiometry of purified SycO and YopO-SycO complexes. SycO alone forms dimers in solution and the YopO-SycO complex has a 1:2 stoichiometry. These results suggested that SycO is a typical chaperone of the Class I. YopO is a serine/theronine kinase that interacts with Rho and Rac and disrupts the cytoskeleton of the target cells. YopO has been shown to localize at the cell plasma-membrane. By transfection of YopO-EGFP hybrid proteins into HEK293T cells, we demonstrated that the chaperone-binding domain (CBD) coincides with the membrane localization domain of YopO. Nevertheless, the CBD was not needed for the kinase activity of YopO. By ultracentrifugation, we also showed that the CBD causes YopO aggregation in the bacteria, when SycO does not cover it. Further, we show that the CBD of YopE and YopT also caused aggregation in the bacteria in the absence of SycE and SycT respectively. YopE, YopT and T3S effectors in other systems also act at the membrane of the eukaryotic host cell. We propose a new hypothesis concerning the role of T3S chaperones. The sub-cellular localization domain of effectors is aggregation-prone and creates the need for a chaperone inside bacteria. We propose that masking such aggregation-prone localization domains may be a general function for type III effector chaperones
Ryhiner-Kartensammlung / 10 Carte de l'Asie
No full textcorrigée, et augmentée, dessus toutes les aultres cy deuant faictes par P. Bertius ; Cornelis Danckerts schulpsitTitelkartusche oben rechts, leere Kartusche oben linksUrsprungswerk: "Les cartes generales de toutes les provinces de France" von Christophe Tassin (Paris, 1634
Modelling Turbulent Combustion Coupled with Conjugate Heat Transfer in OpenFOAM
No full textThis paper verifies a mathematical model that is developed for the open source CFD-toolbox OpenFOAM, which couples turbulent combustion with conjugate heat transfer. This feature already exists in well-known commercial codes. It permits the prediction of the flame’s characteristics, its emissions, and the consequent heat transfer between fluids and solids via radiation, convection, and conduction. The verification is based on a simplified 2D axisymmetric cylindrical reactor. In the first step, the combustion part of the solver is compared against experimental data for an open turbulent flame. This shows good agreement when using the full GRI 3.0 reaction mechanism. Afterwards, the flame is confined by a cylindrical wall and simultaneously conjugate heat transfer is activated and analysed. It is shown that the combustion and conjugate heat transfer are successfully coupled.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Numerical AnalysisMathematical Physic
A Direct Projection to Low-Order Level for p-Multigrid Methods in Isogeometric Analysis
No full textIsogeometric Analysis (IgA) can be considered as the natural extension of the Finite Element Method (FEM) to high-order B-spline basis functions. The development of efficient solvers for discretizations arising in IgA is a challenging task, as most (standard) iterative solvers have a detoriating performance for increasing values of the approximation order p of the basis functions. Recently, p-multigrid methods have been developed as an alternative solution strategy. With p-multigrid methods, a multigrid hierarchy is constructed based on the approximation order p instead of the mesh width h (i.e. h-multigrid). The coarse grid correction is then obtained at level p = 1, where B-spline basis functions coincide with standard Lagrangian P1 basis functions, enabling the use of well known solution strategies developed for the Finite Element Method to solve the residual equation. Different projection schemes can be adopted to go from the high-order level to level p = 1. In this paper, we compare a direct projection to level p = 1 with a projection between each level 1 ≤ k ≤ p in terms of iteration numbers and CPU times. Numerical results, including a spectral analysis, show that a direct projection leads to the most efficient method for both single patch and multipatch geometries.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Numerical Analysi
Dataset and code supporting Cornelis et al. 2023. Stuck in the weeds: Invasive grasses reduce tiger snake movement
No full textData and code used in the publication:
Cornelis, J., Cooper, C. E., Lettoof, D. C., Mayer, M., Marshall, B. M. 2023 Stuck in the weeds: Invasive grasses reduce tiger snake movement. bioRxiv 2023.03.06.531246; doi: https://doi.org/10.1101/2023.03.06.531246
Includes telemetry data, aKDE, dBBMM, and Bayesian model specification and results, code to reproduce analysis and generate figure
Proefsleuvenonderzoek Kindcentrum Cornelis te Uitgeest
No full textIn mei 2021 is door Archeologenbureau Argo een inventariserend veldonderzoek in de vorm van proefsleuven uitgevoerd in het plangebied Kindcentrum Cornelis te Uitgeest. Bij het onderzoek zijn twee proefsleuven aangelegd. Onder recente ophogingen werden Oer-IJ afzettingen aangetroffen met daarin enkele sporen. De aangetroffen sporen bestaan uit twee greppels, één prieltje en één gedempte sloot. Het prieltje dateert mogelijk uit de 9 de of 10 de eeuw. De rest van de sporen dateert uit de Nieuwe Tijd. De vondsten bestonden uit 19 e en 20 e eeuws keramiek en bouwmateriaal en één vroegmiddeleeuwse scherf. Hoewel er sporen van menselijke activiteit zijn gevonden tijdens dit proefsleuvenonderzoek, zijn er geen duidelijke bewoningssporen aangetroffen en is er geen sprake van een behoudenswaardige vindplaats. Dit vormt de aanleiding tot het volgende advies. Voor het plangebied Kindcentrum Cornelis te Uitgeest wordt geadviseerd geen vervolgonderzoek te doen en het plangebied wat betreft archeologie vrij te geven voor de constructie van de geplande nieuwbouw
Das Dreimäderlhaus : Singspiel in drei Teilen
No full textvon A. M. Willner und Heinz Reichert. Musik nach Franz Schubert. Bearb. von Heinrich Berté. Für den Rundfunk eingerichtet von Cornelis BronsgeestTextbuc
Vermaekelyken almanak voor het jaer M. DCC. LXXXIX. ... /
No full textDatum uit titelAchteraan: Catalogus van boeken te koop bij Cornelis de MoorEuropeana-GoogleBook
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