135 research outputs found

    GeoTwain: Geospatial Analysis and Visualisation for Researchers in Transcultural Studies

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    In our research cluster on transculturality many projects deal with georeferenced data. This paper offers an introduction to the new project GeoTwain that works on visualization techniques for such data. Based on an analysis of the global telegraph network as an example of transcultural research using georeferenced data, the paper derives user requirements by combining experiences gained from previous projects and specifies a set of solutions. It is the aim of GeoTwain to provide easy visualization of 4-Dinformation based on Google Earth and to grasp spatial relationships embedded in historical evidence to analyse, recombine and disaggregate geo-referenced historical data without having to use more specialized and highly complex GIS Tools. Envisioned visualization with GeoTwain allows for fast and efficient assessment of georeferencing’s analytical potential in any given case; it also allows the user to carefully weigh further investments in data enrichment in relation to expected findings. Both the development and application of GeoTwain are embedded in the broader research environment infrastructure called Heidelberg Research Architecture (HRA)

    FIM4R Position Paper on the Desired Evolution of EOSC Authentication and Authorisation Infrastructures

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    Authored by: the FIM4R Community The European Open Science Cloud (EOSC) will soon enter the next phase of integration and consolidation with the establishment of a common service portal listing underpinning services that enable distributed resources in the areas of computation, data, open access, and above-the-net collaboration services. The existing e-Infrastructures that are anticipated to be part of the EOSC each provide their own capabilities in terms of trust and identity management, integrity protection and risk management, as well as capabilities to support business continuity and disaster recovery in case of security incidents. There are also specific trust, collaboration management, and security services that are jointly managed by multiple e-Infrastructures for the benefit of (but in many cases not exclusively) the European research and collaboration community as a whole. These include for instance the glue between the EOSC AAI suite of services that each implement the AARC Blueprint Architecture (AARC BPA), i.e. the AAI services such as those from both national and pan-European Infrastructures as well as components such as credential translation bridge services

    Whitepaper der ZKI AG edu-ID zur Verortung des Konzepts einer edu-ID in der aktuellen Landschaft digitaler Identitäten in Deutschland und Europa

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    Ziel dieses Dokuments ist die Einordnung des edu-ID-Konzepts gegenüber anderen Initiativen, Projekten und den jeweiligen Konzepten digitaler Identitäten. Hierbei geht es nicht alleine um die Abgrenzung gegenüber solchen Konzepten, sondern auch um die Identifizierung von Anknüpfungspunkten und möglichen Synergien. Ausgehend von dieser Positionierung werden in einem weiteren Schritt Empfehlungen zu Funktionsumfang, Reichweite und Zielgruppen eines zukünftigen auf dem edu-ID Konzept basierenden Dienstes erarbeitet. Weiterhin werden Überlegungen zum weiteren Vorgehen bei der Entwicklung des Dienstes angestellt

    Federated Identity Management for Research Collaborations

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    This white-paper expresses common requirements of Research Communities seeking to leverage Identity Federation for Authentication and Authorisation. Recommendations are made to Stakeholders to guide the future evolution of Federated Identity Management in a direction that better satisfies research use cases. The authors represent research communities, Research Services, Infrastructures, Identity Federations and Interfederations, with a joint motivation to ease collaboration for distributed researchers. The content has been edited collaboratively by the Federated Identity Management for Research (FIM4R) Community, with input sought at conferences and meetings in Europe, Asia and North America

    Linkage between fitness of yeast cells and adenylate kinase catalysis

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    Enzymes have evolved with highly specific values of their catalytic parameters kcat and KM. This poses fundamental biological questions about the selection pressures responsible for evolutionary tuning of these parameters. Here we are address these questions for the enzyme adenylate kinase (Adk) in eukaryotic yeast cells. A plasmid shuffling system was developed to allow quantification of relative fitness (calculated from growth rates) of yeast in response to perturbations of Adk activity introduced through mutations. Biophysical characterization verified that all variants studied were properly folded and that the mutations did not cause any substantial differences to thermal stability. We found that cytosolic Adk is essential for yeast viability in our strain background and that viability could not be restored with a catalytically dead, although properly folded Adk variant. There exist a massive overcapacity of Adk catalytic activity and only 12% of the wild type kcat is required for optimal growth at the stress condition 20°C. In summary, the approach developed here has provided new insights into the evolutionary tuning of kcat for Adk in a eukaryotic organism. The developed methodology may also become useful for uncovering new aspects of active site dynamics and also in enzyme design since a large library of enzyme variants can be screened rapidly by identifying viable colonies

    Variation in Molybdenum Content Across Broadly Distributed Populations of Arabidopsis thaliana Is Controlled by a Mitochondrial Molybdenum Transporter (MOT1)

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    Molybdenum (Mo) is an essential micronutrient for plants, serving as a cofactor for enzymes involved in nitrate assimilation, sulfite detoxification, abscisic acid biosynthesis, and purine degradation. Here we show that natural variation in shoot Mo content across 92 Arabidopsis thaliana accessions is controlled by variation in a mitochondrially localized transporter (Molybdenum Transporter 1 - MOT1) that belongs to the sulfate transporter superfamily. A deletion in the MOT1 promoter is strongly associated with low shoot Mo, occurring in seven of the accessions with the lowest shoot content of Mo. Consistent with the low Mo phenotype, MOT1 expression in low Mo accessions is reduced. Reciprocal grafting experiments demonstrate that the roots of Ler-0 are responsible for the low Mo accumulation in shoot, and GUS localization demonstrates that MOT1 is expressed strongly in the roots. MOT1 contains an N-terminal mitochondrial targeting sequence and expression of MOT1 tagged with GFP in protoplasts and transgenic plants, establishing the mitochondrial localization of this protein. Furthermore, expression of MOT1 specifically enhances Mo accumulation in yeast by 5-fold, consistent with MOT1 functioning as a molybdate transporter. This work provides the first molecular insight into the processes that regulate Mo accumulation in plants and shows that novel loci can be detected by association mapping

    Identification and characterization of secreted and pathogenesis-related proteins in Ustilago maydis

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    Interactions between plants and fungal pathogens require a complex interplay at the plant–fungus interface. Extracellular effector proteins are thought to play a crucial role in establishing a successful infection. To identify pathogenesis-related proteins in Ustilago maydis we combined the isolation of secreted proteins using a signal sequence trap approach with bioinformatic analyses and the subsequent characterization of knock-out mutants. We identified 29 secreted proteins including hydrophobins and proteins with a repetitive structure similar to the repellent protein Rep1. Hum3, a protein containing both, a hydrophobin domain and a repetitive Rep1-like region, is shown to be processed during passage through the secretory pathway. While single knock-outs of hydrophobin or repellent-like genes did not affect pathogenicity, we found a strong effect of a double knock-out of hum3 and the repetitive rsp1. Yeast-like growth, mating, aerial hyphae formation and surface hydrophobicity were unaffected in this double mutant. However, pathogenic development in planta stops early after penetration leading to a complete loss of pathogenicity. This indicates that Hum3 and Rsp1 are pathogenicity proteins that share an essential function in early stages of the infection. Our results demonstrate that focusing on secreted proteins is a promising way to discover novel pathogenicity proteins that might be broadly applied to a variety of fungal pathogens

    Structural analysis of an eIF3 subcomplex reveals conserved interactions required for a stable and proper translation pre-initiation complex assembly

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    Translation initiation factor eIF3 acts as the key orchestrator of the canonical initiation pathway in eukaryotes, yet its structure is greatly unexplored. We report the 2.2 Å resolution crystal structure of the complex between the yeast seven-bladed β-propeller eIF3i/TIF34 and a C-terminal α-helix of eIF3b/PRT1, which reveals universally conserved interactions. Mutating these interactions displays severe growth defects and eliminates association of eIF3i/TIF34 and strikingly also eIF3g/TIF35 with eIF3 and 40S subunits in vivo. Unexpectedly, 40S-association of the remaining eIF3 subcomplex and eIF5 is likewise destabilized resulting in formation of aberrant pre-initiation complexes (PICs) containing eIF2 and eIF1, which critically compromises scanning arrest on mRNA at its AUG start codon suggesting that the contacts between mRNA and ribosomal decoding site are impaired. Remarkably, overexpression of eIF3g/TIF35 suppresses the leaky scanning and growth defects most probably by preventing these aberrant PICs to form. Leaky scanning is also partially suppressed by eIF1, one of the key regulators of AUG recognition, and its mutant sui1G107R but the mechanism differs. We conclude that the C-terminus of eIF3b/PRT1 orchestrates co-operative recruitment of eIF3i/TIF34 and eIF3g/TIF35 to the 40S subunit for a stable and proper assembly of 48S pre-initiation complexes necessary for stringent AUG recognition on mRNAs

    Residues Clustered in the Light-Sensing Knot of Phytochrome B are Necessary for Conformer-Specific Binding to Signaling Partner PIF3

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    The bHLH transcription factor, PHYTOCHROME INTERACTING FACTOR 3 (PIF3), interacts specifically with the photoactivated, Pfr, form of Arabidopsis phytochrome B (phyB). This interaction induces PIF3 phosphorylation and degradation in vivo and modulates phyB-mediated seedling deetiolation in response to red light. To identify missense mutations in the phyB N-terminal domain that disrupt this interaction, we developed a yeast reverse-hybrid screen. Fifteen individual mutations identified in this screen, or in previous genetic screens for Arabidopsis mutants showing reduced sensitivity to red light, were shown to also disrupt light-induced binding of phyB to PIF3 in in vitro co-immunoprecipitation assays. These phyB missense mutants fall into two general classes: Class I (eleven mutants) containing those defective in light signal perception, due to aberrant chromophore attachment or photoconversion, and Class II (four mutants) containing those normal in signal perception, but defective in the capacity to transduce this signal to PIF3. By generating a homology model for the three-dimensional structure of the Arabidopsis phyB chromophore-binding region, based on the crystal structure of Deinococcus radiodurans phytochrome, we predict that three of the four Class II mutated phyB residues are solvent exposed in a cleft between the presumptive PAS and GAF domains. This deduction suggests that these residues could be directly required for the physical interaction of phyB with PIF3. Because these three residues are also necessary for phyB-imposed inhibition of hypocotyl elongation in response to red light, they are functionally necessary for signal transfer from photoactivated phyB, not only to PIF3 and other related bHLH transcription factors tested here, but also to other downstream signaling components involved in regulating seedling deetiolation
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