66 research outputs found
Organic cultivation in autumn 2016 - Varieties, Seeds and Crop management
The leaflet addresses organic arable farmers and contains a broad overview of varieties. Relevant characteristics of varieties for organic farming and the availability of organic seeds are listed. Additionally, the results of field trials all over the country with winter wheat, winter spelt, winter rye, winter triticale and winter barley are presented
Exploration of Shared Genetic Architecture Between Subcortical Brain Volumes and Anorexia Nervosa
Capturing Relational Schemas and Functional Dependencies in RDFS
Mapping relational data to RDF is an important task for the development of the Semantic Web. To this end, the W3C has recently released a Recommendation for the so-called direct mapping of relational data to RDF. In this work, we propose an enrichment of the direct mapping to make it more faithful by transferring also semantic information present in the relational schema from the relational world to the RDF world. We thus introduce expressive identification constraints to capture functional dependencies and define an RDF Normal Form, which precisely captures the classical Boyce-Codd Normal Form of relational schemas
Changing the Protease Specificity for Activation of a Flavivirus, Tick-Borne Encephalitis Virusâ–ż
The infectivity of flavivirus particles depends on a maturation process that is triggered by the proteolytic cleavage of the precursor of the M protein (prM). This activation cleavage is naturally performed by ubiquitous cellular proteases of the furin family, which typically recognize the multibasic sequence motif R-X-R/K-R. Previously, we demonstrated that a tick-borne encephalitis virus (TBEV) mutant with an altered cleavage motif, R-X-R, produced immature, noninfectious particles that could be activated by exogenous trypsin, which cleaves after single basic residues. Here, we report the adaptation of this mutant to chymotrypsin, a protease specific for large, hydrophobic amino acid residues. Using selection pressure in cell culture, two different mutations conferring a chymotrypsin-dependent phenotype were identified. Surprisingly, one of these mutations (Ser85Phe) occurred three positions upstream of the natural cleavage site. The other mutation (Arg89His) arose at the natural cleavage position but involved a His residue, which is not a typical chymotrypsin cleavage site. Efficient cleavage of protein prM and activation by the heterologous protease were confirmed using various recombinant TBEV mutants. Mutants with only the originally selected mutations exhibited unimpaired export kinetics and were genotypically stable during at least six cell culture passages. However, in contrast to the wild-type virus or trypsin-dependent mutants, chymotrypsin-dependent mutants were not neurovirulent in suckling mice. Our results demonstrate that flaviviruses with altered protease specificities can be generated and suggest that this approach can be used for the construction of viral mutants or vectors that can be activated on demand and have restricted tissue tropism and virulence
Dengue Virus Non-structural Protein 1 Modulates Infectious Particle Production via Interaction with the Structural Proteins.
Non-structural protein 1 (NS1) is one of the most enigmatic proteins of the Dengue virus (DENV), playing distinct functions in immune evasion, pathogenesis and viral replication. The recently reported crystal structure of DENV NS1 revealed its peculiar three-dimensional fold; however, detailed information on NS1 function at different steps of the viral replication cycle is still missing. By using the recently reported crystal structure, as well as amino acid sequence conservation, as a guide for a comprehensive site-directed mutagenesis study, we discovered that in addition to being essential for RNA replication, DENV NS1 is also critically required for the production of infectious virus particles. Taking advantage of a trans-complementation approach based on fully functional epitope-tagged NS1 variants, we identified previously unreported interactions between NS1 and the structural proteins Envelope (E) and precursor Membrane (prM). Interestingly, coimmunoprecipitation revealed an additional association with capsid, arguing that NS1 interacts via the structural glycoproteins with DENV particles. Results obtained with mutations residing either in the NS1 Wing domain or in the β-ladder domain suggest that NS1 might have two distinct functions in the assembly of DENV particles. By using a trans-complementation approach with a C-terminally KDEL-tagged ER-resident NS1, we demonstrate that the secretion of NS1 is dispensable for both RNA replication and infectious particle production. In conclusion, our results provide an extensive genetic map of NS1 determinants essential for viral RNA replication and identify a novel role of NS1 in virion production that is mediated via interaction with the structural proteins. These studies extend the list of NS1 functions and argue for a central role in coordinating replication and assembly/release of infectious DENV particles
Expressive Identification Constraints to Capture Functional Dependencies in Description Logics ⋆
an enormous growth of the Semantic Web through initiatives like Open Linked Data [5] and Open Government Data [14, 25]. As was noted by He et al. [13] and Madhavan et al. [17], to a large extent, the data accessible on the web still originates from relational databases. The design of these databases often follows specific principles, called normal forms, developed in the beginnings of relational database research, see, e.g., [11, 12]. The goal of this work is to transfer these principles, in particular the Boyce-Codd Normal Form (BCNF), to RDF graphs enhanced with RDFS statements. To establish and justify this normal form for RDF graphs, we need the following: (1) A mapping of relational databases to RDF graphs and (2) identification constraints that capture functional dependencies (FDs) over RDF graphs. For (1), W3C has recognized the importance of a standardized mapping of relational data to the Semantic Web data format RDF. To this end, the so-called direct mapping has been released as a W3C Recommendation [2]. Note that the direct mapping to RDF does not transfer the semantic information that ma
A Benchmark Collection of Hypergraphs
<p>2191 hypergraph instances containing hypergraphs that originate in CQs and CSPs instances from various sources.</p>
<p>See Johannes K. Fichte, Markus Hecher, Neha Lodha, and Stefan Szeider: An SMT Approach to Fractional Hypertree Width, Proceedings of the 24th International Conference on Principles and Practice of Constraint Programming (CP2018) for details on the original sources of the benchmarks.</p
Secretion kinetics and ultrastructural characterization of ΔNS1<sup>TCP</sup>-infected helper cell lines.
<p>(<b>A</b>–<b>B</b>) <i>Kinetics of DVR2A</i><sup><i>ΔNS1</i></sup><i>TCPs secretion from helper cell lines</i>. (A) Schematic representation of the experimental setting. DVR2A<sup>ΔNS1</sup> TCPs produced in VeroE6_NS1<sup>WT</sup> cells (ΔNS1-WT<sup>TCP</sup>) were used to infect (MOI = 1) control or helper cell lines expressing different forms of NS1. Culture supernatants were collected 24, 48 and 72 h later, and virus titers were determined by Focus forming unit (FFU) assay on VeroE6_NS1<sup>WT</sup> cells, using an E-specific mouse monoclonal antibody. Cell lysates and culture supernatants were analyzed by western blot. (B) FFU titers were determined as specified in panel (A). As reference, naïve VeroE6 cells were infected with DVR2A. The dashed line indicates the limit of detection of the assay. The lower panel shows representative images of foci morphologies of each trans-complemented NS1 variant. (<b>C</b>) <i>Expression levels of intra- and extra-cellular NS1 in DVR2A</i><sup><i>ΔNS1</i></sup><i>TCP infected cells</i>. NS1 expression and secretion were evaluated by western-blotting using cell lysates (Intra-) or clarified supernatants (Extra-) from (B) and NS1-, NS5- or GAPDH specific antibodies. (<b>D</b>, <b>E</b>) <i>Ultrastructural characterization of cells infected with DVR2A</i><sup><i>ΔNS1</i></sup><i>TCPs</i>. VeroE6_NS1<sup>HA</sup> cells were infected with 1 MOI of DVR2A<sup>ΔNS1</sup> TCPs. Forty-eight hours later, cells were fixed, processed and analyzed by transmission electron microscopy as described in materials and methods. Representative images of the perinuclear area (D) or plasma membrane (E) of infected cells are shown. Black arrowheads indicate Vesicle packets (VPs), red arrowheads indicate virion bags. Electron-dense virus particles in proximity to or at the plasma membrane are indicated with black arrows. Boxed areas on the left panels are shown at higher magnification on the right. Black or white scale bars represent 500 or 200 μm, respectively.</p
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