Enzymes involved in biosynthesis and degradation of poly-[alpha]2,8-sialic acid : structure-function relationships

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Open Educational Resources als neue Aufgabe für Wissenschaftliche Bibliotheken

Open Educational Resources (OER) sind sich in Deutschland bisher hauptsächlich im Bereich der schulischen Bildung im Gespräch. Ihr Potential innerhalb der deutschen Hochschullehre wurde zwar bereits erkannt, wird aber bisher noch nicht genutzt. Die Arbeit gibt einen Überblick über die terminologischen Grundlagen von OER und ihren Entwicklungsmöglichkeiten im Hochschulbereich. In einer Zusammenfassung werden die Förderung von OER durch die Europäische Kommission und in Deutschland, sowie ihre Entwicklung im deutschen Hochschulbereich dargestellt. In einem theoretischen Abgleich aktueller Studien und Fachliteratur wird eine Bestandsaufnahme zu neuen Aufgabenbereichen für Wissenschaftlicher Bibliotheken durch OER durchgeführt. Eine Expertenbefragung, die beispielhaft unter Lehrenden der Leibniz Universität Hannover (LUH) durchgeführt wurde, gibt Aufschluss über deren aktuellen Nutzungsstand von OER. Die wird ergänzt durch eine Untersuchung zweier Sharingdienste (Zenodo und SlideShare) nach freien Lehrmaterialien von Angehörigen der LUH. Abschließend werden auf der Basis der theoretischen Möglichkeiten sowie der individuellen Bedürfnisse der Lehrenden Empfehlungen für neue Dienstleistungen und Serviceangebote Wissenschaftlicher Bibliotheken zur Unterstützung der Hochschulen bei der Einführung, Herstellung und Verbreitung von OER am Beispiel der Technischen Informationsbibliothek Hannover (TIB) gegeben, sowie neue Aufgabenbereiche für Hochschulbibliotheken skizziert, die sich daraus ergeben

Open Education an (Hochschul-)Bibliotheken: Ideen und Strukturen

Workshop 7: Open Educational Resources als gemeinsames Zukunftsprojekt für Hochschulen und Bibliotheken: Potentiale und Strategie

Das #vBIB20-Experiment: spontan, agil und virtuell

After the cancellation of the 109th German Librarians' Day in Hannover, the #vBIB20 took place from 26-28 May 2020 as an alternative planned at short notice, which was conducted as a web conference. The article briefly examines from the point of view of the organisation (TIB Hannover, Association of Information and Library Professionals BIB) the challenges and experiences in the implementation of the pure online conference, which was unprecedented in the German-speaking library community on this scale.Nach Absage des 109. Deutschen Bibliothekartags in Hannover fand als kurzfristig geplante Alternative vom 26.-28. Mai 2020 die #vBIB20 statt, welche als Webkonferenz durchgeführt wurde. Der Artikel beleuchtet kurz aus Sicht der Organisation (TIB Hannover, Berufsverband Information Bibliothek BIB) die Herausforderungen und Erfahrungen in der Umsetzung der reinen Online-Tagung, welche in der deutschsprachigen bibliothekarischen Fachcommunity in dieser Größenordnung noch ohne Beispiel war

Das #vBIB20-Experiment: spontan, agil und virtuell

Nach Absage des 109. Deutschen Bibliothekartags in Hannover fand als kurzfristig geplante Alternative vom 26.-28. Mai 2020 die #vBIB20 statt, welche als Webkonferenz durchgeführt wurde. Der Artikel beleuchtet kurz aus Sicht der Organisation (TIB Hannover, Berufsverband Information Bibliothek BIB) die Herausforderungen und Erfahrungen in der Umsetzung der reinen Online-Tagung, welche in der deutschsprachigen bibliothekarischen Fachcommunity in dieser Größenordnung noch ohne Beispiel war. After the cancellation of the 109th German Librarians' Day in Hannover, the #vBIB20 took place from 26-28 May 2020 as an alternative planned at short notice, which was conducted as a web conference. The article briefly examines from the point of view of the organisation (TIB Hannover, Association of Information and Library Professionals BIB) the challenges and experiences in the implementation of the pure online conference, which was unprecedented in the German-speaking library community on this scale

A Multivalent Adsorption Apparatus Explains the Broad Host Range of Phage phi92: a Comprehensive Genomic and Structural Analysis

Bacteriophage phi92 is a large, lytic myovirus isolated in 1983 from pathogenic Escherichia coli strains that carry a polysialic acid capsule. Here we report the genome organization of phi92, the cryoelectron microscopy reconstruction of its virion, and the re-investigation of its host specificity. The genome consists of a linear, double-stranded 148,612-bp DNA sequence containing 248 potential open reading frames and 11 putative tRNA genes. Orthologs were found for 130 of the predicted proteins. Most of the virion proteins showed significant sequence similarities to proteins of myoviruses rv5 and PVP-SE1, indicating that phi92 is a new member of the novel genus of rv5-like phages. Reinvestigation of phi92 host specificity showed that the host range is not limited to polysialic acid-encapsulated Escherichia coli but includes most laboratory strains of Escherichia coli and many Salmonella strains. Structure analysis of the phi92 virion demonstrated the presence of four different types of tail fibers and/or tail-spikes, which enable the phage to use attachment sites on encapsulated and nonencapsulated bacteria. With this report, we provide the first detailed description of a multivalent, multispecies phage armed with a host cell adsorption apparatus resembling a nanosized Swiss army knife. The genome, structure, and, in particular, the organization of the baseplate of phi92 demonstrate how a bacteriophage can evolve into a multi-pathogen-killing agent

Geometrical principles of homomeric β-barrels and β-helices: Application to modeling amyloid protofilaments

Examples of homomeric β-helices and β-barrels have recently emerged. Here we generalise the theory for the shear number in β-barrels to encompass β-helices and homomeric structures. We introduce the concept of the “β-strip”, the set of parallel or antiparallel neighbouring strands, from which the whole helix can be generated giving it n-fold rotational symmetry. In this context the shear number is interpreted as the sum around the helix of the fixed register shift between neighbouring identical β-strips. Using this approach we have derived relationships between helical width, pitch, angle between strand direction and helical axis, mass per length, register shift, and number of strands. The validity and unifying power of the method is demonstrated with known structures including α-haemolysin, T4 phage spike, cylindrin, and the HET-s(218-289) prion. From reported dimensions measured by X-ray fibre diffraction on amyloid fibrils the relationships can be used to predict the register shift and the number of strands within amyloid protofilaments. This was used to construct models of transthyretin and Alzheimer β(40) amyloid protofilaments that comprise a single strip of in-register β-strands folded into a “β-strip helix”. Results suggest both stabilisation of an individual β-strip helix as well as growth by addition of further β-strip helices involves the same pair of sequence segments associating with β-sheet hydrogen bonding at the same register shift. This association would be aided by a repeat sequence. Hence understanding of how the register shift (as the distance between repeat sequences) relates to helical dimensions, will be useful for nanotube design

Morphogenesis of the T4 tail and tail fibers

Remarkable progress has been made during the past ten years in elucidating the structure of the bacteriophage T4 tail by a combination of three-dimensional image reconstruction from electron micrographs and X-ray crystallography of the components. Partial and complete structures of nine out of twenty tail structural proteins have been determined by X-ray crystallography and have been fitted into the 3D-reconstituted structure of the "extended" tail. The 3D structure of the "contracted" tail was also determined and interpreted in terms of component proteins. Given the pseudo-atomic tail structures both before and after contraction, it is now possible to understand the gross conformational change of the baseplate in terms of the change in the relative positions of the subunit proteins. These studies have explained how the conformational change of the baseplate and contraction of the tail are related to the tail's host cell recognition and membrane penetration function. On the other hand, the baseplate assembly process has been recently reexamined in detail in a precise system involving recombinant proteins (unlike the earlier studies with phage mutants). These experiments showed that the sequential association of the subunits of the baseplate wedge is based on the induced-fit upon association of each subunit. It was also found that, upon association of gp53 (gene product 53), the penultimate subunit of the wedge, six of the wedge intermediates spontaneously associate to form a baseplate-like structure in the absence of the central hub. Structure determination of the rest of the subunits and intermediate complexes and the assembly of the hub still require further study